Patent Publication Number: US-5159022-A

Title: Crystalline block copolymer and process for producing the same

Description:
This application is a continuation of application Ser. No. 07/342,653 filed on Apr. 25, 1989, which is a continuation of application Ser. No. 07/017,235 filed on Feb. 20, 1987, both now abandoned. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a novel block copolymer comprising a conjugated diene and a vinylaromatic compound and a process for producing the same. More specifically, the present invention relates to a block copolymer containing at least a set of 1,4-transconjugated diene polymer block having crystallinity at 25° C. sandwiched, between two or more vinylaromatic hydrocarbon polymer blocks each having a glass transition temperature of not lower than 50° C. and a process for producing the same. 
     BACKGROUND ART 
     A preparation technique of using an I A  metal compound such as organic lithium, etc., as the polymerization catalyst can give a block copolymer of a vinylaromatic monomer and a conjugated diene monomer. This technique is accomplished by utilizing its living anion polymerization characteristic of successively polymerizing a vinylaromatic monomer and a conjugated diene monomer, and also, if necessary, performing the terminal coupling reaction. These block copolymers, when containing a relatively small amount of the vinylaromatic compound, have an elasticity at normal temperatures similar to vulcanized natural rubber or synthetic rubber, and yet can be processed at higher temperatures similarly as thermoplastic resins. For this reason, they are called thermoplastic elastomers, and have been widely used in the field of plastic modifiers, tackifiers, etc. On the other hand, when the content of the vinylaromatic compound is relatively high, thermoplastic resins excellent in transparency and impact resistance can be obtained and they have been widely utilized, primarily in the field of packaging vessels for foods. However, the trans-linkage content at the conjugated diene portion of the polymer obtained according to such a process will generally never exceed 60%, and thus no block copolymer having a crystalline trans-conjugated diene polymer block have ever been obtained. 
     On the other hand, conjugated diene polymers having higher trans-1,4-linkage content have been known to have been produced according to the three techniques shown below. 
     (1) The preparation technique of using a Ziegler catalyst containing a transition metal as the main component. 
     (2) The preparation technique of using an anion polymerization catalyst system comprising an alkaline earth metal compound as the main component. 
     (3) The preparation technique of using a catalyst system comprising a rare earth metal compound as the main component. 
     The first technique which comprises using a transition metal such as nickel, cobalt, titanium, vanadium, etc., as the main component has been known to effect a high degree of stereoregular polymerization of a conjugated diene monomer. However, due to low living polymerization activity and low copolymerizability with a vinylaromatic monomer, it has been difficult to produce a block copolymer of a conjugated diene monomer and a vinylaromatic monomer according to these preparation techniques. 
     As to the second technique, there is an example in which an organometal compound of II A  metal is used as the polymerization catalyst, but an organometallic compound of II A  metal other than beryllium, magnesium can be generally synthesized but only with difficulty, and their polymerization activities were also markedly low. While organometallic compounds of beryllium and magnesium can be synthesized with relative ease, polymerization activity for conjugated dienes cannot be exhibited except for special reaction conditions, and only polymers having low molecular weight could be obtained. In contrast, as the method in which a II A  metal salt of an organic acid of metals such as barium and strontium is combined with other organometallic compounds, the methods have been known in which polymerization of a conjugated diene monomer is conducted by using barium-di-tert-butoxide and an organolithium (U.S. Pat. No. 3,992,561), barium-ditert -butoxide and an organomagnesium (U.S. Pat. No. 3,846,385) or an organic compound of barium or strontium, an organolithium and an organometallic compound of II B  or III A  metal (U.S. Pat. No. 4,092,268), etc. In these methods, using a composite catalyst containing an II A  metal compound, polymers having high molecular weight can be obtained and further copolymerization of a conjugated diene monomer with a vinylaromatic monomer is possible. However, when it is desired to obtain a polymer exhibiting crystallinity with high stereoregularity having a trans-linkage content at the conjugated diene portion exceeding 80%, the polymerization temperature is required to be made lower, whereby polymerization activity becomes lower. Particularly, when it is desired to subject a conjugated diene monomer and a vinylaromatic monomer to block copolymerization, the reaction is required to be completed for each block of polymerization reaction, and therefore high living characteristic is demanded for the active terminals. Accordingly, although there is an example in which a diblock copolymer of butadiene and styrene with a relatively lower molecular weight is obtained (U.S. Pat. No. 4,355,156), there is no block copolymer obtained with a structure as intended by the present invention. 
     Further, as to the third technique, there has been known a polymerization catalyst comprising an organoneodymium salt of Versatic Acid and an organomagnesium (European Patent 0091287). According to this technique, although a crystalline butadiene polymer having high trans-linkage content can be obtained, polymerization activity, particularly copolymerizability with a vinylaromatic monomer such as styrene, etc., is remarkably low, and no block copolymer of a conjugated diene monomer and vinylaromatic monomer has been obtained. 
     In the techniques using the polymerization catalysts of the prior art as described above, problems are involved in their catalyst characteristics, and therefore no block copolymer containing a crystalline conjugated diene polymer block having a trans-linkage content at the conjugated diene portion of 80% or higher sandwiched between two or more polymer blocks of vinylaromatic compounds as purposed for by the present invention has been obtained, and no such kind of polymer has been known up to date. 
     Under such a situation, the present inventors have investigated intensively about the method for preparation of a copolymer containing a crystalline trans-conjugated diene polymer block and vinylaromatic compound polymer blocks and consequently developed a process for producing the same, and found that the copolymer obtained has extremely specific properties which enables the present invention to be accomplished. 
    
    
     BRIEF DESCRIPTION OF DRAWING 
     FIG. 1 is a graph showing the GPC measurement results of the polymer prepared in Example 1. 
    
    
     DISCLOSURE 
     More specifically, the present invention relates to a crystalline block copolymer containing at least a triblock chain represented by the formula A-B-C or at least a radial structure represented by the formula (D-E) n  X in the polymer chain and a process for producing the same. In the formula, A, C and D each represents a block of a homopolymer of a vinylaromatic compound or a copolymer of a vinylaromatic compound with another vinylaromatic compound or a conjugated diene compound having a glass transition temperature (tg) of not lower than 50° C. and having a weight average molecular weight in the range of from 2,000 to 100,000; B and E each represent a block comprising a homopolymer of a conjugated diene compound or a copolymer of a conjugated diene compound with another diene compound or a copolymer of a conjugated diene compound having less than 20 wt. % of a vinylaromatic compound having a 1,4-trans linkage content at the conjugated diene portion of 80% or higher, having weight average molecular weights in the range of from 25,000 to 1,000,000 and from  10,000 to 500,000 respectively, a glass transition temperature of not higher than 10° C. and crystallinity at 25° C.; X is a terminal coupling agent; and n is an integer of from 2 to 10. 
     Such crystalline block copolymers exhibit different characteristics depending primarily on their composition ratios of conjugated diene and vinylaromatic compound. 
     The following cases may be included. 
     (1) In the case where the content of the vinylaromatic compound is relatively small, and since the conjugated diene block portion tends to be remarkably oriented and crystallized, a thermoplastic resin which is remarkably high in hardness and strength and excellent in resilience is obtained. 
     Particularly, when the content of the vinylaromatic compound in the crystalline block copolymer is 5 to 60 wt. %, preferably 20 to 40 wt. %, and the melting point of the conjugated block is 25° C. or higher and lower than the glass transition temperature of the vinylaromatic hydrocarbon block, preferably lower by 10° C. or more than the glass transition temperature, the polymer exhibits an excellent shape memorizing characteristic. 
     For example, when a sample of such a polymer molded at a temperature exceeding the glass transition temperature of the vinylaromatic hydrocarbon block is deformed at a temperature lower than the glass transition temperature of the vinylaromatic hydrocarbon block and at which most of the conjugated diene block is melted and cooled to near the room temperature, and whereby this shape is frozen and retained, and when this is again heated to the temperature used during deformation of the conjugated diene block, the shape of the sample molded can be rapidly restored, thus showing an excellent shape memorizing characteristic. 
     (2) In the case, when the content of the vinylaromatic compound is relatively higher, a thermoplastic resin having high hardness and strength and excellent impact resistance can be obtained. 
     Thus, an object of the present invention is to provide a crystalline block copolymer having various excellent characteristics as mentioned above. 
     An object of the present invention is to provide a crystalline block copolymer containing at least a triblock chain represented by the formula A-B-C in the polymer chain, or a crystalline block copolymer containing at least a radial structure represented by the formula (D-E) n  X in the polymer chain. 
     In the above formulae, A, C and D each represent a block comprising a homopolymer of a vinylaromatic compound or a copolymer of a vinylaromatic compound with another vinylaromatic compound or a conjugated diene compound having a glass transition temperature of not lower than 50° C. and a weight average molecular weight in the range of from 2,000 to 100,000. 
     If the glass transition temperature of the blocks of A, C and D is lower than 50° C., the physical properties such as strength and elongation, etc., of the copolymer obtained will be undesirably lowered remarkably. Also, if the weight average molecular weight is less than 2,000, the physical properties such as strength and elongation, etc., of the copolymer will be undesirably lowered. On the other hand, if the molecular weight exceeds 100,000, processability of the copolymer will be undesirably remarkably lowered. The blocks of A, C and D should preferably be a homopolymer of a vinylaromatic compound or a copolymer of a vinylaromatic compound with another vinylaromatic compound, but it may be also a random or tapered copolymer of a vinylaromatic compound with less than 50 wt. % of a conjugated diene compound. 
     The blocks of B and E have respective weight average molecular weights in the range of 25,000 to 1,000,000 and from 10,000 to 500,000, having a glass transition temperature not higher than 10° C. and crystallinity at 25° C., which is a homopolymer of a conjugated diene compound, or a copolymer of a conjugated diene compound with another conjugated diene compound or a copolymer of a conjugated diene compound and less than 20 wt. % of a vinylaromatic compound respectively having a 1,4-trans linkage content at the conjugated diene portion of 80% or higher. 
     If the weight average molecular weight of the block B is less than 25,000 or the weight average molecular weight of the block E is less than 10,000, the physical properties such as elongation and resilience, etc., of the copolymer obtained will be undesirably lowered. If the respective weight average molecular weights of the blocks B and E exceed 1,000,000 or 500,000, processability of the copolymer obtained will be undesirably remarkably lowered. 
     Also, if the glass transition temperature of the blocks of B and E exceeds 10° C., the resilience or shape memorizing characteristic of the copolymer obtained will be undesirably lowered. 
     The blocks of B and E must have crystallinity at 25° C. That is, its melting point must be 25° C. or higher. Blocks of B and E have preferably a melting point of 25° C. or higher, which are lower than the glass transition temperature of the block of the corresponding blocks A, C or D, preferably lower by 10° C. or lower than the glass transition temperature. 
     When the blocks of B and E has no crystallinity at 25° C., the resultant copolymer will be lowered in hardness and strength, and its shape memorizing characteristic will be undesirably remarkably lowered. 
     Also, if the 1,4-trans-linkage content at the conjugated diene portion in the blocks of B and E is less than 80%, the resultant copolymer will be lowered in strength and elongation, and the shape memorizing characteristic will be undesirably remarkably lowered. 
     Further, the block of B and E are each a homopolymer of a conjugated diene compound, a copolymer of a conjugated diene compound with another conjugated diene compound or a copolymer of a conjugated diene compound having less than 20 wt. % of a vinylaromatic compound, and a content of the vinylaromatic compound in the block in excess of 20 wt. % will result in undesirable lowering in resilience or a shape memorizing characteristic of the copolymer obtained. The mode of copolymerization may be either random copolymerization or tapered copolymerization. 
     In the crystalline block copolymer of the present invention, other than the above blocks of A, B, C or the blocks of D and E, blocks having structures not defined in the present invention such as conjugated diene polymer blocks having less than 80% of 1,4-trans-linkage content, etc., may also be contained between the respective blocks or outside of the blocks in the polymer chain, to the extent which does not lose the basic characteristics of the polymer of the present invention. 
     In the formula representing the structure of the crystalline block copolymer of the present invention, n is an integer of 2 or more, and 10 or less. If n is 1, the physical properties such as strength, elongation, etc., of the polymer obtained will be remarkably lowered, and also the shape memorizing characteristic will be undesirably lowered. On the other hand, if n is 11 or higher, processability will be undesirably remarkably lowered. X shows a terminal coupling agent, and may be selected generally from the coupling agents used in the terminal coupling reaction in anion polymerization of conjugated dienes. 
     Examples of the monomers constituting the crystalline block copolymer of the present invention may include, as vinylaromatic compounds, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-tert-butylstyrene, dimethylstyrene, vinylnaphthalene, etc., and, as conjugated diene compounds, butadiene, isoprene, piperylene, etc. Particularly preferable monomers are styrene and butadiene, respectively. 
     The crystalline block copolymer of the present invention may also contain, in addition to the triblock copolymer of the above formula A-B-C and the radial block copolymer of the formula (D-E) n  X, impurities formed as a matter of course during polymerization, such as 1,4-trans-conjugated diene polymer, vinylaromatic compound polymer, diblock copolymer comprising 1,4-transconjugated diene polymer block and a vinylaromatic compound block. However, also in this case, the effect of the present invention cannot be fully exhibited, unless 30 wt. % or more of the A-B-C triblock copolymer or the (D-B) n  X radial block copolymer is contained. 
     The crystalline block copolymer of the present invention can be used alone, but it may be sometimes preferably used as a mixture with other polymers for further improvement of softening temperature, rigidity, strength, resilience, moldability, etc., of the polymer depending on the use. However, also in this case, the effect of the present invention intended by the present invention cannot be fully exhibited unless at least 30% or more of the crystalline block copolymer is contained as the polymer component. Particularly preferable examples which can be mixed may include crystalline polymers having low melting points within the range of from 25° C. to 150° C. such as transbutadiene polymers, transisoprene polymers, ε-caprolactone polymers, etc., and polymers having aromatic nuleus such as styrene polymers, styrene-butadiene copolymers, α-methylstyrene polymers, cumarone-indene resins, polyphenylene ether, etc. 
     Further, other than the above polymeric components, inorganic fillers or plasticizers can be also formulated if desired for controlling rigidity or plasticity, etc. Also, stabilizers, pigments, etc., which are general additives to be added in polymeric resin materials can be also added conveniently similarly as in the prior art resin materials. 
     The amount of inorganic fillers to be used may be 5 to 100 parts by weight per 100 parts by weight of the polymeric components. Examples of inorganic fillers may include titanium oxide, calcium carbonate, clay, talc, mica, bentonite, silica, carbon, etc. Use of inorganic fillers in excess of 100 parts by weight will undesirably lower the impact strength of the polymeric resin material obtained. 
     The amount of the plasticizers used may be generally within the range of from 1 to 20 parts by weight per 100 parts by weight of the polymeric components. Examples of the plasticizers may include dibutyl phthalate, di-(2-ethylhexyl) phthalate, di-(2-ethylhexyl) adipate, diethylene glycol dibenzoate, butyl stearate, butylepoxy stearate, tri-(2-ethylhexyl) phosphate, various petroleum oils, etc. 
     The crystalline block copolymer of the present invention can be mixed easily by an extruder, a kneader, rolls, etc. These devices can be set at temperatures which can be freely selected within the range of from 60° to 200° C., but preferably from 80° to 180° C. Also, they can be mixed in a solution by dissolving in a suitable solvent. 
     The polymer or the polymer composition thus obtained can be utilized for various resin materials by making avail of the specific features thereof, namely the specific features in the physical properties such as shape memorizing characteristic, rigidity, strength, impact strength, etc., and processability such as injection moldability, low temperature workability, reworkability, etc. 
     For example, (1) they can be utilized for fixing materials of affected portions for medical purposes such as splint, plaster cast, etc., and protector materials for various sports by making avail of specific features primarily of rigidity, impact resistance and low temperature workability, (2) for heat-shrinkable films, laminates provided with heat shrinkability by application of previous stretching treatment, (3) for toys, dolls, artificial flowers or heat-sensitive sensors by making avail of its excellent shape memorizing characteristic, (4) for heat-shrinkable sleeve, coupling device, insulating material of wires in electrical products by utilizing, securing or coating by heating shrinkage, (5) for various frame work materials, frame work material of head portion for wigs, by making avail of the specific feature of fitness to the mold surface by heat shrinkage and possibility of heated working and modification at fine portions. 
     Another object of the present invention is to provide a process for preparing a novel copolymer comprising vinylaromatic hydrocarbon polymer blocks and crystalline trans-1,4 conjugated diene polymer block having various excellent characteristics as described above. The preparation techniques are classified and described in detail below. (1) A crystalline block copolymer containing the triblock chain represented by the formula of A-B-C can be prepared, by using a composite catalyst comprising the catalyst components (a), (b) and (c), or (a), (b), (c) and (d) as shown below, and by polymerizing successively the monomers selected from vinylaromatic monomers, conjugated diene monomers or mixtures thereof, wherein 
     (a) is an organic compound of barium or strontium; 
     (b) is an organic compound of lithium; 
     (c) is an organomagnesium compound; 
     (d) is an organoaluminum or organozinc compound. 
     The essential catalyst components in the process of the present invention are (a), (b) and (c), whereby the object of the present invention can be fully accomplished, but the catalyst component (d) can also be used in combination if desired. By using the catalyst component (d) in combination, sometimes there may be the effect of improvement of catalytic activity or increase of the trans-linkage content at the conjugated diene portion. 
     The amount of the organomagensium which is the catalyst component (c) to be used, which may also depend on the molecular weight of the desired polymer, may be generally within the range of from 0.1 to 50 mmols per 100 g of the total monomers, preferably from 0.5 to 5 mmol. If the amount of the organomagnisium used is less than 0.1 mmol, the polymerization activity of the catalyst will be generally remarably lowered , and the molecular weight of the polymer obtained will be remarkably increased to make processability difficult. On the other hand, at an amount of the organomagnesium content in excess of 50 mmols, the molecular weight of the polymer obtained will become undesirably lower. 
     The amount of the organic compound of lithium which is the catalyst component (b) to be used may be within the range of from Li/Mg=0.1 to 10 as represented in terms of molar ratio of lithium to magnesium, preferably from 0.5 to 2. At a lithium content of less than Li/Mg=0.1, polymerization activity, particularly polymerization initiation rate will be undesirably lowered remarkably. On the other hand, at a lithium content over Li/Mg=10, at the stage of polymerization of the conjugated diene monomer, the ratio of 1,4-trans linkage of the conjugated diene will be lowered to a great extent, whereby the polymer obtained becomes non-crystalline and the object of the present invention cannot be accomplished. 
     The amount of the catalyst component (a) to be used, namely the organic compound of barium or strontium may be within the range of Me 1  /Mg=0.005 to 10 (Me 1  is barium or strontium metal) as represented in terms of molar ratio relative to magnesium, preferably from 0.1 to 1. At a ratio less than Me 1  /Mg=0.005, at the stage of polymerization of the conjugated diene monomer, the ratio of 1,4-trans linkage of the conjugated diene will be lowered to a great extent, whereby the polymer obtained becomes non-crystalline and the objects of the present invention cannot be accomplished. On the other hand, at a content over Me 1  /Mg=10, the polymerization activity of the composite catalyst will be undesirably remarkably lowered. 
     In the composite catalyst used in the preparation process of the present invention, further in addition to the above catalyst components (a), (b) and (c), an organoaluminum or organozinc may be also used as the catalyst component (d), if desired. The amount of the catalyst component (d) used may be Me 2  /Mg=50 or less (Me 2  represents aluminum or zinc metal), preferably Me 2  / Mg=5 or less, particularly preferably 1 or less. By addition of the catalyst component (d), the ratio of the 1,4-trans linkage at the conjugated diene portion can be increased, but the polymerization activity of the composite catalyst will be undesirably remarkably lowered at an amount in excess of Me 2  /Mg=50. 
     (2) A crystalline block copolymer containing the radial structure represented by the formula (D-E) n  X can be prepared according to a process, which comprises using the composite catalyst comprising the catalyst components (a), (b) and (c) or (a), (b), (c) and (d), polymerizing successively the monomers selected from vinylaromatic monomers, conjugated diene monomers or mixtures thereof, and thereafter carrying out the reaction with addition of a coupling agent, wherein 
     (a) is an organic compound of barium or strontium; 
     (b) is an organic compound of lithium; 
     (c) is an organomagnesium compound; 
     (d) is an organoaluminum or organozinc compound. 
     The essential catalyst components in the present preparation process are (a), (b) and (c), and the object can be accomplished by using these, but the catalyst component (d) can be also used if desired. Use of the catalyst component (d) in combination may sometimes have the effect of improving the catalyst activity or increasing the trans-linkage content at the conjugated diene portion. 
     The preferable amounts and composition of the catalyst components used and their effects are the same as described above. 
     As the coupling agent, there may be employed coupling agents generally used in the terminal coupling reaction in anion polymerization of conjugated dienes. Examples of useful coupling agents may include multiepoxide, multi-isocyanate, multi-imine, multi-aldehyde, multi-ketone, multi-acid anhydride, multi-ester, monoester, multihalide, carbon monoxide and carbon dioxide. Particularly preferable coupling agents are silicon multihalide compounds such as tetrachloro-silane, trichloromonomethylsilane, trichloromonoethylsilane, dichlorodiethylsilane, etc., tin multihalide compounds such as tetrachloro tin, trichloromonomethyl tin, etc., ester compounds such as diphenylcarbonate, methylbenzoate, ethylbenzoate, diethyladipate, etc. The amount of the coupling agent used may be considered to be optimum for maximum branching when used in an amount equivalent to the organic metal employed. However, depending on the degree of coupling desired, the amount within any range of a coupling agent may be available. Generally, the amount of a coupling agent used is in the amount of 0.1 to 1.5 equivalent of an organomagnesium. The coupling agent may be added alone or as a solution in an inert hydrocarbon. The coupling agent may be added at once, in divided portions or continuously. The coupling reaction may be conducted under conditions which may also differ, but generally the reaction is conducted at a temperature approximate to the polymerization temperature and for a period of several minutes to several hours. 
     (3) Another process for preparing the crystalline block copolymer containing the radial structure represented by the formula (D-E) n  X comprises, copolymerizing a vinylaromatic monomer or conjugated diene monomer by using a composite catalyst comprising the catalyst components (b) and (c), and then with addition of the catalyst component (e) homopolymerizing a conjugated diene monomer or copolymerizing with one or more of other conjugated diene monomers or aromatic vinyl monomers, and then carrying out the reaction with the addition of a coupling agent: 
     (b) is an organic compound of lithium; 
     (c) is an organomagnesium compound; and 
     (e) is a rare earth metal salt of an organic acid. 
     The amount of the organomagnesium employed, which may also depend on the molecular weight of the desired polymer, may generally be from 0.1 to 50 mmols, preferably 0.5 to 5 mmols, per 100 g of the total monomers. If the organomagnesium compound used is less than 0.1 mmol, the polymerization activity of the catalyst will be generally remarkably lowered and the molecular weight of the polymer obtained will be remarkably increased to ensue the problem such that processability of the polymer becomes undesirably difficult. On the other hand, if the content of organomagnesium is in excess of 50 mmols, rare earth metal the molecular weight of the polymer obtained becomes remarkably lower, which is generally undesirable. 
     On the other hand, the amount of the organic compound of lithium may be in the range of Li/Mg=0.1 to 10, preferably 0.5 to 2 as represented in terms of molar ratio of lithium to magnesium. At a lithium content less than Li/Mg=0.1, polymerization activity during polymerization of the vinylaromatic monomer prior to addition of the rare earth metal compound will be undesirably remarkably lowered. On the other hand, at a lithium content over Li/Mg=10, at the stage of polymerization of conjugated diene monomer by addition of the rare earth metal compound, the ratio of the 1,4-trans linkage of conjugated dienes will be lowered to a great extent, whereby the polymer obtained becomes non-crystalline and the objects of the present invention cannot be accomplished. 
     In the preparation process of the present invention, generally after polymerization of the block of vinylaromatic hydrocarbon polymers, a rare earth metal salt of an organic acid is added and after the reaction, the second stage polymerization of crystalline trans conjugated diene polymer block is carried out, and if necessary it is possible to obtain substantially the same results by simultaneous addition of the rare earth metal salt of an organic acid and the conjugated diene monomer. 
     The amount of the rare earth metal salt of an organic acid used may be within the range of Ln/Mg=0.01 to 1, preferably 0.05 to 0.5 in terms of molar ratio relative to the organomagnesium compound used. 
     If the amount of the organic acid salt of rare earth metal used is less than 0.01 of Ln/Mg, the ratio of the 1,4-trans linkage of conjugated diene will be lowered to a great extent, whereby the polymer obtained will undesirably become non-crystalline. On the other hand, if Ln/Mg is in excess of 1, the polymerization activity will be lowered to a great extent undesirably. 
     In adding the rare earth metal salt of an organic acid, further an organic compound of lithium, an organomagnesium or an organoaluminum or organozinc compound may be added to the polymerization system previously mixed with the rare earth metal salt of an organic acid or directly for increasing the 1,4-trans linkage of conjugated diene or promoting the living growth of the reaction terminals. 
     The types of coupling agents to be reacted and the reaction conditions to be used after polymerization are the same as described above. 
     After the reaction, stabilizers and antioxidants, known in this field of art, can be added to the polymer and further recovered according to the method known in this field of art. Particularly preferable examples of stabilizers and antioxidants may include 2,6-di-tert-butyl-4-methylphenol, tri-nonylphenylphosphate, phenyl-β-naphthylamine, N,N&#39;-dialkyldiphenylamine, N-alkyl-diphenylamine, etc. As the method for recovery of the polymer, steam stripping, heating drying, etc., may be employed. 
     Examples of the vinylaromatic monomer which can be used in the present invention may include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-tert-butylstyrene, dimethylstyrene, vinylnaphthalene, etc. Particularly preferable vinylaromatic monomer is styrene. 
     As the copolymerizable conjugated diene, butadiene, isoprene, piperylene, etc., may be employed. Particularly preferable conjugated diene is butadiene. 
     Polymerization can be practiced in the absence or presence of a solvent. In the latter case, useful solvents may include aliphatic or alicyclic hydrocarbons such as n-pentane, n-hexane, n-heptane, cyclohexane, etc., aromatic hydrocarbons such as benzene, toluene, etc. Also, the solvent may contain partially polar organic compounds containing no active hydrogen such as tertially amines and ethers for the purpose of accelerating the polymerization reaction, improving solubility of the catalyst, etc. 
     The polymerization temperature may be -30° C. to 150° C., preferably 50° C. to 120° C. 
     The polymerization reaction system is not particularly limited, but generally the batch method is preferred. 
     The organic compound of barium or strontium which is the catalyst component (a) of the composite catalyst to be used in the preparation process of the present invention may be selected from among those represented by the following formulae (I) to (VIII). ##STR1## (wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8  and R 9  each represent an aliphatic hydrocarbon group or an aromatic hydrocarbon group, a and b each represents an integer of 6 or less, c represents an integer of 2 to 8, X represents oxygen or sulfur atom, and Me represents a metal of barium or strontium). 
     Examples of the above formula (I) may include barium or strontium salts of alcohols, phenols, thioalcohols, or thiophenols such as ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, 2-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, cyclohexyl alcohol, allyl alcohol, cyclopentyl alcohol, benzyl alcohol, phenol, 1-naphthol, 2,6-ditert -butylphenol, 2,4,6-tri-tert-butylphenol, nonylphenol, 4-phenylphenol, ethanethiol, 1-butanethiol, thiophenol, cyclohexanethiol, 2-naphthalenethiol, etc. 
     Examples of the formula (II) may include barium or strontium salts of carboxylic acids or sulfur analogues such as isovaleric acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, cyclopentanecarboxylic acid, naphthenic acid, ethylhexanoic acid, pivalic acid, Versatic Acid (synthetic acid constituted of a mixture of isomers of C10 mono-carboxylic acids sold by Shell Chemical Co.), phenylacetic acid, benzoic acid, 2-naphthoic acid, hexanethionic acid, 2,2-dimethylbutanethionic acid, decanethionic acid, tetradecanethionic acid, thiobenzoic acid and the like. 
     Examples of the formula (III) may include barium or strontium salts of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, diethylene glycol monophenyl ether, etc. 
     Examples of the formula (IV) may include barium or strontium salts of dimethylaminoethanol, diethylaminoethanol, di-n-propylaminoethanol, etc. 
     Examples of the formula (V) may include barium or strontium salts of secondary amines such as dimethylamine, diethylamine, di-n-propylamine, di-isopropylamine, di-n-butylamine, di-n-hexylamine, and the like. 
     Examples of the formula (VI) may include barium or strontium salts of cyclic imines such as ethyleneimine, triethyleneimine, pyrrolidine, piperidine, hexamethyleneimine, and the like. 
     Examples of the formula (VII) may include barium or strontium salts of butanesulfonic acid, hexanesulfonic acid, decanesulfonic acid, tridecanesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, di-iso-propylnaphthalenesulfonic acid, n-hexylnaphthalenesulfonic acid, dibutylphenylsulfonic acid, and the like. 
     Examples of the formula (VIII) may include barium or strontium salts of sulfate esters of lauryl alcohol, oleyl alcohol, stearyl alcohol, and the like. 
     The organic compounds of lithium which is the catalyst component (b) in the composite catalyst to be used in the preparation process of the present invention may be selected from organolithium or lithium salts of an organic acid represented by the following formula (IX) to (XIV). ##STR2## (wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6  and R 7  each represents an aliphatic hydrocarbon group or an aromatic hydrocarbon group, a, b, c and d each represents an integer of 1 to 6, e represents an integer of 2 to 8, and X represents oxygen or sulfur atom). 
     Examples of the formula (IX) may include methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, isoamyllithium, sec-amyllithium, n-hexyllithium, n-octyllithium, allyllithium, benzylhexyllithium, phenyllithium, 1,1-diphenyllithium, tetramethylenedilithium, pentamethylenedilithium, 1,2-dilithio-1,1,2,2-tetraphenylethane, 1,3-bis(1-lithio-1,3-dimethylpentyl)benzene, and the like. 
     Examples of the formula (X) may include lithium salts of alcohols, phenols, thioalcohols and thiophenols such as ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, 2-butyl alcohol, tert-butyl alcohol, n-amyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, cyclohexyl alcohol, allyl alcohol, cyclopentyl alcohol, benzyl alcohol, phenol, 1-naphthol, 2,6-di-tert-butylphenol, 2,4,6-tri-tert-butylphenol, nonylphenol, 4-phenylphenol, ethanethiol, 1-butanethiol, thiophenol, cyclohexanethiol, 2-naphthalenethiol, and the like. 
     Examples of the formula (XI) may include lithium salts of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, diethylene glycol monophenyl ether, and the like. 
     Examples of the formula (XII) may include lithium salts of dimethylaminoethanol, diethylaminoethanol, di-n-propylaminoethanol, and the like. 
     Examples of the formula (XIII) may include lithium salts of secondary amines such as dimethylamine, diethylamine, di-n-propylamine, di-iso-propylamine, di-n-butylamine, di-n-hexylamine, and the like. 
     Examples of the formula (XIV) may include lithium salts of cyclic imines such as ethyleneimine, triethyleneimine, pyrrolidine, piperidine, hexamethyleneimine, and the like. 
     Particularly preferable organic compounds of lithium are alkyllithium having 2 to 10 carbon atoms such as n-butyllithium, sec-butyllithium and iso-amyllithium, etc. 
     The organomagnesium compound which is the catalyst component (C) in the composite catalyst to be used in the preparation process of the present invention is represented by the following formula (XV): ##STR3## (wherein R 1  and R 2  each represents an aliphatic hydro carbon group or an aromatic hydrocarbon group, which may be either the same or different). 
     Also, the organomagnesium compound may also contain a small amount of organoaluminum or organozinc, etc., for improvement of its solubility in hydrocarbon solvents. 
     Examples of such compounds may include preferably diethylmagnesium, di-n-propylmagnesium, di-isopropylmagnesium, di-n-butylmagnesium, n-butyl sec-butylmagnesium, di-sec-butylmagnesium, di-tertbutylmagnesium, di-n-hexylmagnesium, di-n-propylmagnesium, diphenylmagnesium, MAGALA-6E [Texas Alkyl Co., molecular formula 6(n-C 4  H 9 ) 2  Mg.(C 2  H 5 ) 3  Al], MAGALA-7.5E [Texas Alkyl Co., molecular formula 7.5(n-C 4  H 9 ) 2 . (C 2  H 5 ) 3  Al], more preferably diisopropylmagnesium, di-n-butylmagnesium, di-sec-butylmagnesium, MAGALA-6E, MAGALA-7.5E, etc. 
     As the catalyst component (d) in the composite catalyst to be used in the preparation process of the present invention, there may be employed an organometallic compound selected from organoaluminum or organozinc. 
     The organoaluminum to be used may be represented by the following formula (XVI). ##STR4## (wherein R 1 , R 2  and R 3  are selected from hydrogen, aliphatic hydrocarbon groups or aromatic hydrocarbon groups, which may be either the same or different, but all should not be hydrogen atoms at the same time). 
     Examples of such compounds may include triethylaluminum, tri-iso-butylaluminum, tri-n-propylaluminum, tri-iso-propylaluminum, tri-n-hexylaluminum, diethylaluminum monohydride, and the like. 
     The organozinc to be used is represented by the following formula (XVII). 
     
         R.sup.1 --Zn--R.sup.2                                      (XVII) 
    
     (wherein R 1  and R 2  are selected from hydrogen, aliphatic hydrocarbon groups or aromatic hydrocarbon groups which may be either the same or different, but both of R 1  and R 2  are not hydrogen). 
     Examples of such compounds may include diethylzinc, di-n-propylzinc, di-iso-amylzinc, di-iso-butylzinc, and the like. 
     The rare earth metal salt of an organic acid which is a catalyst component (e) in the composite catalyst to be used in the preparation process of the present invention is a salt of an organic acid represented by the following formulae (XVIII) to (XXV). ##STR5## (wherein R 1  and R 2  and R 5  -R 8  each represents a hydrocarbon group or an aromatic hydrocarbon group, R 3  represents an aromatic hydrocarbon group, R 4  represents an aliphatic hydrocarbon group, R 9  -R 12  each represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an alkoxy group or a phenoxy group; X represents an oxygen atom or a sulfur atom; and a, b, c and d each represents an integer of 1 to 6). 
     The above formula (XVIII) represents alcohols, thioalcohols, phenols or thiophenols. Examples of these may include methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, tert-butyl alcohol, tert-amyl alcohol, n-hexyl alcohl, cyclohexyl alcohol, alyl alcohol, 2-butenyl alcohol, 3-hexenyl alcohol, 2,5-decadienyl alcohol, benzyl alcohol, phenol, catechol, 1-naphthol, 2-naphthol, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tri-tert-butylphenol, 4-phenylphenol, ethanethiol, 1-butanethiol, 2-pentane thiol, 2-iso-butanethiol, thiophenol, 2-naphthalenethiol, cyclohexanethiol, 3-methylcyclohexanethiol, 2-naphthalenethiol, benzenemethanethiol, 2-naphthalenemethanethiol, and the like. 
     The formula (XIX) represents carboxylic acids or sulfur analogues thereof. Examples of these may include isovaleric acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, cyclopentanecarboxylic acid, naphthenic acid, ethylhexanoic acid, pivalic acid, Versatic Acid (synthetic acid constituted of a mixture of isomers of C10 monocarboxylic acids sold by Shell Chemical Co.), phenylacetic acid, benzoic acid, 2-naphthoic acid, hexanethionic acid, 2,2-dimethylbutane-thionic acid, decanethionic acid, tetradecanethionic acid, thiobenzoic acid, and the like. 
     The formula (XX) represents alkylallylsulfonic acids. Examples may include dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, n-hexylnaphthalenesulfonic acid, dibutylphenylsulfonic acid, and the like. 
     The formula (XXI) represents monoalcohol esters of sulfuric acid. Examples of these may include sulfuric acid monoesters of lauryl alcohol, oleyl alcohol, stearyl alcohol, and the like. 
     The formula (XXII) represents phosphoric acid diesters of ethylene oxide adducts of alcohol or phenol. Examples of these may include phosphoric acid diester of ethylene oxide adduct of dodecyl alcohol, phosphoric acid diester of ethylene oxide adduct of octyl alcohol, phosphoric acid diester of ethylene oxide adduct of stearyl alcohol, phosphoric acid diester of ethylene oxide adduct of oleyl alcohol, phosphoric acid diester of ethylene oxide adduct of nonylphenol, phosphoric acid ester of ethylene oxide adduct of dodecylphenol, and the like. 
     The formula (XXIII) represents phosphite diesters of ethylene oxide adducts of alcohol or phenol. Examples of these may include phosphite diester of ethylene oxide adduct of dodecyl alcohol, phosphite diester of ethylene oxide adduct of stearyl alcohol, phosphite diester of ethylene oxide adduct of stearyl alcohol, phosphite diester of ethylene oxide adduct of nonylphenol, phosphite diester of ethylene oxide adduct of dodecylphenol, and the like. 
     The formula (XXIV) represents pentavalent organic phosphoric acid compounds. Examples of these may include dibutylphosphate, dipentylphosphate, dihexylphosphate, diheptylphosphate, dioctylphosphate, bis(1methylheptyl)phosphate, bis(2-ethylhexyl)phosphate, dilaurylphosphate, dioleylphosphate, diphenylphosphate, bis(p-nonylphenyl)phosphate, (butyl)(2-ethylhexyl)phosphate, (1-methylheptyl)(2-ethylhexyl)phosphate, (2-ethylhexyl)(p-nonylphenyl)phosphate, monobutyl-2-ethyl-hexylphosphonate, mono-2-ethylhexylphenylphosphonate, mono-2-ethylhexyl-2-ethylhexylphosphonate, mono-p-nonyl-phenyl-2-ethylhexylphosphonate, dibutylphosphinic acid, bis(2-ethylhexyl)phosphinic acid, bis(1-methylheptyl)-phosphinic acid, dilaurylphosphinic acid, dioleyl-phosphinic acid, diphenylphosphinic acid, bis(p-nonyl-phenyl)phosphinic acid, butyl(2-ethylhexyl)phosphinic acid, (2-ethylhexyl)(1-methylheptyl)phosphinic acid, (2-ethylhexyl)(p-nonylphenyl)phosphinic acid, and the like. 
     The formula (XXV) represents trivalent phosphoric acid compounds. Examples of these may include bis(2-ethylhexyl)phosphate, bis(1-methylheptyl)phosphate, mono-2-ethylhexyl-2-ethylhexylphosphonate, bis(2-ethylhexyl)phosphinic acid, and the like. 
     Useful rare earth metals are lanthanide elements of the atomic numbers 57 to 71, preferably elements of the atomic numbers 57 to 64, particularly preferably lanthanum, and cerium. These rare earth metals are not required to be particularly of high purity, but they may be a mixture with other rare earth elements, or may also contain a small amount of metal elements other than rare earth metals. The rare earth metal salt of an organic acid may also contain a small amount of unreacted organic acid. 
     As described in detail above, the present invention provides a novel crystalline block copolymer containing vinylaromatic hydrocarbon polymer block and crystalline trans-conjugated diene polymer blocks having various excellent characteristics---for example, various characteristics useful as excellent resin such as hardness, strength, resilience, etc. (and also having useful properties as shape memorizing resin) and further excellent impact resistance--and a process for preparation thereof. 
     EXAMPLES 
     The present invention is described in detail by referring to the following Examples, by which the scope of the present invention is not limited. 
     EXAMPLE 1 
     A polymerization reactor of 10 liter volume equipped with a stainless steel stirrer internally replaced with nitrogen gas is charged with 1.5 kg of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried, and then 0.0113 mol of dibutyl magnesium (produced by Lithium Corp.; n-butyl : s-butyl about 1 : 1), 0.0113 mol of sec-butyl lithium as the catalyst components and 0.034 mol of tetrahydrofuran (THF) as the polymerization accelerator are added, followed by polymerization at 65° C. for 3 hours. At this point, a small amount of the polymerized solution is sampled from the reactor for analysis. As the result, the polymerization conversion by gas chromatograph analysis is 100%, the number average molecular weight by gel permeation chromatography (GPC) is Mn=8,900, with the molecular weight distribution represented by the ratio ralative to the weight average molecular weight being Mw/Mn=1.16. The GPC measurement conditions are shown below. 
     (a) GPC=LC-6A produced by Shimazu Seisakusho 
     (b) Eluent=THF 
     (c) Column temperature=40° C. 
     Subsequently, after 0.0023 mol pf bis(2-ethylhexyl)phosphate of lanthanum metal is added into the polymerized solution, 3.5 kg of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged, followed further by polymerization at 65° C. for 3 hours. At this point, a part of the polymerized solution is sampled for analysis to find that polymerization conversion of butadiene is 98%. Further, the polymer at this point is found to be a mixture of polymers containing a large amount of styrene-butadiene diblock polymer as clearly seen from the GPC measurement results shown in Table 1. The bound styrene concentration distribution in FIG. 1 is calculated by measuring the molecular weight distribution from the refractive index in GPC with styrene concentration correction and also measuring the styrene concentration from UV-ray absorbance. The polymer as a whole is found to have Mn=32,600, and Mw/Mn=1.40. 
     Also, from FIG. 1, it can be seen that most of the polymers are styrene-butadiene diblock polymers, although containing small amounts of styrene homopolymers and butadiene homopolymers. The polymer content of the diblock polymer calculated from these GPC measurement results is 87%. 
     The polymerized solution is further subjected to the reaction at 65° C. for 1 hour by charging diphenylcarbonate as the terminal coupling agent in an amount of equal mols to the magnesium amount remaining in the reactor. As the result of the coupling reaction, the molecular weight of the polymer became Mn=64,000, Mw/Mn=1.45, thus indicating a great extent of increase in molecular weight. The final polymer recovery is 97%. 
     EXAMPLE 2 
     Example 1 was repeated except that 2.0 kg of a cyclohexane solution containing 20 wt. % of styrene and 3.0 kg of a cyclohexane solution containing 20 wt. % of 1,3-butadiene are used as the monomers. 
     EXAMPLE 3 
     Example 1 is repeated except that 1.0 kg of a cyclohexane solution containing 20 wt. % of styrene and 4.0 kg of a cyclohexane solution containing 20 wt. % of 1,3-butadiene were used as the monomers. 
     EXAMPLE 4 
     Example 1 is repeated except that the polymerization conditions of 1,3-butadiene are changed to 50° C. and 24 hours. 
     EXAMPLE 5 
     Example 1 is repeated except that 0.0085 mol of dibutylmagnesium and 0.017 mol of sec-butyllithium are used as the catalyst components. 
     EXAMPLE 6 
     A polymerization reactor of 10 liter volume equipped with a stainless steel stirrer internally replaced with nitrogen gas is charged with 0.5 kg of a cyclohexane solution containing 20 wt. % of previously purified and dried 1,3-butadiene and 1.5 kg of a cyclohexane solution containing 20 wt. % of purified and dried styrene, and then 0.0113 mol of dibutylmagnesium and 0.0113 mol of sec-butyllithium as the catalyst components, and 0.034 mol of tetrahydrofuran (THF) as the polymerization accelerator were added, followed by polymerization at 65° C. for 3 hours. 
     Subsequently, after 0.0023 mol of bis(2ethylhexyl)phosphate of lanthanum metal is added into the polymerized solution, 3.5 kg of cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged, followed further by polymerization at 65° C. 3 hours. 
     The polymerized solution is further subjected to the reaction at 65° C. for 1 hour by charging diphenylcarbonate as the terminal coupling agent in an amount of equal mols to the magnesium amount remaining in the reactor. 
     EXAMPLE 7 
     A polymerization reactor of 10 liter volume equipped with a stainless steel stirrer internally replaced with nitrogen gas is charged with 1.5 kg of a cyclohexane solution containing 20 wt. % of purified and dried styrene, and then 0.0113 mol of dibutylmagnesium and 0.0113 mol of sec-butyllithium as the catalyst components, and 0.034 mol of tetrahydrofuran (THF) as the polymerization accelerator are added, followed by polymerization at 65° C. for 3 hours. 
     Subsequently, after 0.0023 mol gf bis(2ethylhexyl)phosphate of lanthanum metal is added into the polymerized solution, 3.3 kg of cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene and 0.2 kg of a cyclohexane solution containing 20 wt. % of purified and dried isoprene is charged, followed further by polymerization at 65° C. for 3 hours. 
     The polymerized solution is further subjected to the reaction at 65° C. for 1 hour by charging diphenylcarbonate as the terminal coupling agent in an amount of equal mols to the magnesium amount remaining in the reactor. 
     EXAMPLE 8 
     A polymerization reactor of 10 liter volume equipped with a stainless steel stirrer replaced internatally with nitrogen is charged with 0.7 kg of a cyclonally hexane solution containing 20 wt. % of styrene previously purified and dried, and then 0.0038 mol of barium dinonyl phenoxide, 0.0057 mol of dibutylmagnesium, 0.0057 mol of sec-butyllithium and 0.008 mol of triethylaluminum are added, followed by polymerization at 70° C. for 2 hours. At this point, a small amount of the polymerized solution is sampled from the reactor for analysis. As the result, polymerization conversion by gas chromatograph analysis is 97%, the number average molecular weight Mn by gel permeation chromatography (GPC) analysis is 9,600, and the molecular weight distribution represented by the ratio relative to the weight average molecular weight is Mw/Mn=1.16. 
     Next, into the polymerized solution is charged 3.5 kg of a cyclohexane solution containing 20 wt. % of, purified and dried 1,3-butadiene, and polymerization is further conducted at 65° C. for 3 hours. Also, at this point, a part of the polymerized solution is sampled for analysis to find that the polymerization conversion of butadiene is 90%. The polymer as a whole at this point is found to have Mn=58,000, Mw/Mn=1.23. 
     Into the polymerized solution is further added 0.8 kg of a cyclohexane solution containing 20 Wt.% of purified and dried styrene, and polymerization is further continued at 70° C. for 3 hours. When a part of the polymerized solution is simpled for analysis, the final conversion of butadiene is found to be 99%, and the whole conversion of styrene 87%. 
     COMPARATIVE EXAMPLE 1 
     Example 1 was repeated except that no bis(2ethylhexyl)phosphate of lanthanum metal is added during polymerization. 
     COMPARATIVE EXAMPLE 2 
     Example 8 is repeated except that only 0.017 mol of sec-butyllithium is used as the catalyst component. 
     COMPARATIVE EXAMPLE 3 
     Example 1 is repeated except that 0.0067 mol of dibutylmagnesium, 0.0067 mol of sec-butyllithium and 0.0014 mol of bis(2-ethylhexyl)phosphate of lanthanum metal are used as the polymerization catalyst, and 0.020 mol of tetrahydrofuran is used as the polymerization accelerator, and no diphenylcarbonate which is the terminal coupling agent is used. 
     The structures of the polymers obtained in Examples 1-8, Comparative Examples 1-3, and the polymer characteristics by using test strips press molded at 150° C. are shown in Table 1. 
     
         TABLE 1
  Example No. Comparative Example No. 1 2 3 4 5 6 7 8 1 2 3
   Polymer structure             Polymer chain structure  (D-E).sub.3--X
 same as same as same as same as same as same as A-B-C (straight (D-E).sub
 .3--X A-B-C (straight A-B   (radial) left left left left left left chain
 triblock) (radial) chain triblock) (diblock) 1,4-Trans content at *1 (%)
 87 87 89 92 82 83 89 84 53 52 88 butadiene portion Bound styrene *1 (wt
 %)   30.4   40.7   20.1   30.9   30.3   30.1   30.3   26.2   29.8   30.0
   30.2 content Weight average *2 (× 10.sup.4)   9.3   9.5   9.5
 9.2   9.3   9.7   9.4   8.2   7.9   9.1   6.1 molecular weight Molecular
 weight *2 (--Mw/--Mn)    1.45    1.47    1.41    1.50    1.43    1.43
 1.46    1.27    1.24    1.15
  1.40 distribution Polymer characteristics M.P. of butadiene *3 (°
 C.) 65 71 80 86 45 74 52 55 (none) (none) 75 portion Glass transition *3
 (°C.) -91  -92  -92  -93  -89  -89  -92  -90  -94  -94  -91
 temp. of butadiene portion Glass transition *3 (°C.) 97 98 94 98
 95 88 95 85 95 94 97 temp. of styrene portion M I *4 (g/10 min.)   1.7
 2.1   1.1   2.3   1.2   1.5   1.9   2.1   2.4   1.7   3.4 Hardness *5
 (JIS-A) 92 94 97 99 86 89 92 86 82 80 92 Strength *5 (kg/cm.sup.2) 340
 380  300  380  280  210  260  220  190  150  120  Elongation *5 (%) 700
 520  720  550  750  580  740  780  650  580  180  Residual elongation *5
 (%) 560  400  580  420  480  450  500  550  40 30 90 at break Resilience
 *6 (%) 58 56 60 60 57 57 56 56 54 53 56 Shape recovery *7 (°C.)
 60 65 70 80 40 65 45 50 shape not shape not not temp.          fixed
 fixed recovered Shape recovery *7 (%) 95 90 95 85 80 90 95 90 -- --
 Note:
 *1 Measured according to the Hampton method by using IRspectrophotometer.
 *2 Measured by gel permeation chromatography.
 *3 Measured by differential scanning calorimeter.
 190° Test temperature 192° C., test load 2.16 kg.
 *5 Measured according to JIS K6301.
 *6 Measured by Dunlop Flexometer at 25° C.
 *7 A test strip of 5 mm × 2 mm × 10 cm is bent at an angle of
 180° at a temperature of 80° C., and quenched as such to
 20° C. to fix the shape. Next, the temperature of the test strip i
 gradually raised and the temperature at which the angle becomes 90.degree
 is defined as the shape recovery temperature. Further, the temperature is
 raised to 80° C., and the restoration degree of the bent angle is
 expressed as the restoration percentage.
 
    
     EXAMPLE 9 
     Polymerization is carried out in the same manner as in Example 1 except for using isoprene in place of butadiene. Styrene conversion after completion of polymerization is found to be 100%, and isoprene conpolymerization version 84%. The structure of the polymer obtained and the polymer characteristics by using a test strip press molded at 150° C. are shown in Table 2. 
     
                       TABLE 2                                                     
______________________________________                                    
Polymer structure                                                         
Polymer chain structure       (D-E ) .sub.3--X                            
1,4-Trans content at isoprene *1                                          
                   (%)        94                                          
portion                                                                   
Bound styrene content *1                                                  
                   (wt %)       31.2                                      
Weight average molecular *2                                               
                   (× 10.sup.4)                                     
                                8.8                                       
weight                                                                    
Molecular weight *2                                                       
                   (-- Mw/-- Mn)                                          
                                 1.47                                     
distribution                                                              
Polymer characteristics                                                   
M.P. of isoprene portion *3                                               
                   (°C.)                                           
                              46                                          
Glass transition temp. of *3                                              
                   (°C.)                                           
                              95                                          
styrene portion                                                           
M I *4             (g/10 min.)                                            
                                2.0                                       
Hardness *5        (JIS-A)    85                                          
Strength *5        (kg/cm.sup.2)                                          
                              220                                         
Elongation *5      (%)        580                                         
Residual elongation at *5                                                 
                   (%)        470                                         
break                                                                     
Resilience *6      (%)        54                                          
Shape recovery temp. *7                                                   
                   (°C.)                                           
                              35                                          
Shape recovery *7  (%)        85                                          
______________________________________                                    
 Note:                                                                    
 *1 Measured by NMR                                                       
 *2˜7 Are the same as in Examples 1˜8.                        
 
    
     EXAMPLES 10-13 
     A pressure glass bottle of 700 ml volume internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next, as the catalyst components, 0.5 mmol of barium dinonyl phenoxide, 0.67 mmol of dibutylmagnesium, 0.67 mmol of sec-butyllithium, and 0.89 mmol of triethylaluminum are added and polymerization is carried out at 70° C. under stirring for 3 hours. At this point, a small amount of the polymerized solution is sampled for analysis. Next, 280 g of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, followed further by polymerization at 65° C. for 3 hours. After the polymerization, the compound as shown in Table 3 is added as the terminal coupling agent in the amount shown in the same Table, and the reaction is carried out at 65° C. for 1 hour. After the reaction, the reaction is stopped by addition of 1 ml of methanol, and 0.3 parts of di-tert butylhydroxytoluene (hereinafter called BHT) is added per, 100 parts by weight of the polymer and the solvent is evaporated to recover the polymer. The results a shown in Table 3. 
     
                                           TABLE 3                                 
__________________________________________________________________________
                  Monomer conversion                                      
                                  Polymer characteristics                 
                                                        Polymer           
Coupling agent    Styrene conversion                                      
                            Final             Trans-linkage               
                                                        composition       
Ex-          Amount                                                       
                  on completion                                           
                            butadiene                                     
                                  Molecular   content at                  
                                                        Coupling          
ample        added                                                        
                  of styrene                                              
                            conversion                                    
                                  weight, etc.                            
                                              butadiene                   
                                                     M.P.                 
                                                        polymer           
No. Compound (m mol)                                                      
                  polymerization (%)                                      
                            (%)   -- Mw (× 10.sup.4)                
                                         -- Mw/-- Mn                      
                                              portion (%)                 
                                                     (°C.)         
                                                        content           
__________________________________________________________________________
                                                        (%)               
10  tetrachlorosilane                                                     
             0.50 100       92    13.5   1.31 84     68 84                
11  tetrachlorotin                                                        
             0.50 100       94    12.1   1.29 83     65 84                
12  ethyl adipate                                                         
             0.50 100       92    12.7   1.27 83     63 80                
13  diphenyl  0.335                                                       
                  100       93     8.2   1.45 83     62 57                
    carbonate                                                             
__________________________________________________________________________
 
    
     Polymerization conversions of styrene and butadiene are determined by analysis by gas chromatography, the molecular weights, the molecular weight distributions and the polymer compositions by analysis according to gel permeation chromatography (GPC) under the conditions shown in Example 1, the content of trans-1,4 linkage at the butadiene portion in the polymer by analysis by an IR-spectrophotometer and calculation according to the Hampton method and the melting point according to analysis by differential scanning calorimeter (DSC). 
     The polymer characteristics of the polymers obtained in Examples 10-13 by using the test strips pressmolded at 150° C. are shown in Table 4. 
     The measuring conditions are the same as in Table 1. 
     
                       TABLE 4                                                     
______________________________________                                    
               Example No.                                                
               10    11      12      13                                   
______________________________________                                    
Polymer characteristics                                                   
Glass transition                                                          
           (°C.)                                                   
                     96      97    95    97                               
temp. of styrene                                                          
portion                                                                   
M I        (g/10 min.)                                                    
                       0.8     1.1   1.0   2.5                            
Hardness   (JIS-A)   87      86    86    85                               
Strength   (kg/cm.sup.2)                                                  
                     360     370   350   240                              
Elongation (%)       700     680   700   580                              
Residual elonga-                                                          
           (%)       560     540   550   460                              
tion at break                                                             
Resilience (%)       60      58    58    57                               
Shape recovery                                                            
           (°C.)                                                   
                     60      60    60    55                               
temp.                                                                     
Shape recovery                                                            
           (%)       95      95    95    85                               
______________________________________                                    
 
    
     EXAMPLES 14-24 
     The crystalline block copolymers shown in Example 1 are kneaded with other polymers, inorganic fillers or plasticizers at the compositions shown in Table 5 by a Laboplastmil (produced by Toyo Seiki Seisakusho K.K.) at 150° C. and a screw rotational number of 50 rpm for 5 minutes, and the physical properties of the respective compositions are evaluated. The results obtained are shown in Table 5. 
     
                                           TABLE 5                                 
__________________________________________________________________________
                  Example No.                                             
                  14 15 16 17 18 19 20 21 22 23 24                        
__________________________________________________________________________
Crystalline block *1                                                      
              (parts)                                                     
                  70 70 50 30 70 70 100                                   
                                       100                                
                                          100                             
                                             100                          
                                                100                       
copolymer                                                                 
Trans-butadiene polymer *2                                                
              (parts)                                                     
                  30 -- -- -- -- -- -- -- -- -- --                        
ε-caprolactone *3                                                 
              (parts)                                                     
                  -- 30 50 70 -- -- -- -- -- -- --                        
polystyrene *4                                                            
              (parts)                                                     
                  -- -- -- -- 30 -- -- -- -- -- --                        
polyphenyleneoxide *5                                                     
              (parts)                                                     
                  -- -- -- -- -- 30 -- -- -- -- --                        
titanium oxide *6                                                         
              (parts)                                                     
                  10 10 10 10 10 10 -- -- 50 70 50                        
talc *7       (parts)                                                     
                  -- -- -- -- -- --  10                                   
                                       -- -- -- --                        
silica *8     (parts)                                                     
                  -- -- -- -- -- -- --  10                                
                                          -- -- --                        
dibutyl phthalate                                                         
              (parts)                                                     
                  -- -- -- -- -- -- -- -- 10 20 --                        
butyl stearate                                                            
              (parts)                                                     
                  -- -- -- -- -- -- -- -- -- -- 10                        
Hardness      (JIS-                                                       
                  92 94 95 97 94 94  91                                   
                                        94                                
                                          96 96 96                        
              A)                                                          
Strength      (kg/                                                        
                  260                                                     
                     280                                                  
                        250                                               
                           190                                            
                              320                                         
                                 340                                      
                                    220                                   
                                       260                                
                                          200                             
                                             160                          
                                                190                       
              cm.sup.2)                                                   
Elongation    (%) 610                                                     
                     700                                                  
                        710                                               
                           700                                            
                              650                                         
                                 630                                      
                                    700                                   
                                       580                                
                                          480                             
                                             380                          
                                                460                       
Residual elongation                                                       
              (%) 450                                                     
                     560                                                  
                        560                                               
                           570                                            
                              510                                         
                                 500                                      
                                    570                                   
                                       430                                
                                          400                             
                                             320                          
                                                390                       
at break                                                                  
Shape recovery temp.                                                      
              (°C.)                                                
                  60 60 58 55 65 65  60                                   
                                        65                                
                                          65 70 65                        
Shape recovery                                                            
              (%) 85 90 85 75 85 90  90                                   
                                        85                                
                                          85 80 85                        
__________________________________________________________________________
 Note:                                                                    
  *1 Polymer shown in Example 1                                           
 *2 Butadiene polymer having a 1,4trans linkage content of 84%, a weight  
 average molecular weight of 79000, and a molecular weight distribution   
 (--Mw/--Mn) of 1.18                                                      
 *3 Placcel H7 (produced by Dicel Kagaku Kogyo K.K.)                      
 *4 Styrene polymer having a weight average molecular weight of 42000, and
 a molecular weight distribution (--Mw/--Mn) of 1.24                      
 *5 Polyphenylene oxide having a weight average molecular weight of 12000 
 *6 Titanium white A100 (produced by Ishihara Sangyo K.K.)                
 *7 Fine powder talc                                                      
 *8 Nipsil VN3 (produced by Nippon Silica Kogyo K.K.)                     
 
    
     EXAMPLES 25-33 
     A pressure glass bottle of 700 ml volume which is internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Then, 0.50 mmol of a barium salt of an organic acid shown in Table 6, 0.67 mmol of dibutylmagnesium (produced by Lithium Corp., n-Butyl : s-Butyl=about 1 : 1), 0.67 mmol of sec-butyllithium, and 0.89 mmol of triethylaluminum are added, and polymerization is carried out at 70° C. for 3 hours. At this point, a small amount of the polymerized solution is sampled for analysis. Next, 280 g of cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, and polymerization is further carried out at 65° C. for 3 hours. Then, with addition of 0.67 mol of purified and dried methylbenzoate, the reaction is carried out at 65° C. for 30 minutes. After the reaction, polymerization is stopped with addition of 1 ml of methanol, and 0.3 parts by weight of BHT was added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The analyticla method is the same as in Example 1. The results are shown in Table 6. 
     The polymerization conversions of styrene and butadiene are determined by analysis according to gas chromatography, the molecular weight, molecular weight distribution and the composition of the polymers by analysis according to gel permeation chromatography (GPC) under the conditions in Example 1, the trans-1,4 linkage content at the butadiene portion in the polymer by analysis according to IR-spectrophotometer, calculation according to the Hampton method, and the melting point by analysis according to differential scanning calorimeter (DSC). 
     
                                           TABLE 6                                 
__________________________________________________________________________
          Monomer conversion                                              
                     Polymer characteristics                              
          Styrene                                                         
                 Final           Trans-                                   
          conversion on                                                   
                 buta-           linkage  Polymer composition             
Ex-       completion of                                                   
                 diene           content at                               
                                          Coupling                        
                                               Diblock                    
                                                    Butadiene             
                                                          Styrene         
am-       styrene                                                         
                 con-                                                     
                     Molecular   butadiene                                
                                          polymer                         
                                               copoly-                    
                                                    homo- homo-           
ple       polymeriza-                                                     
                 version                                                  
                     weight, etc.                                         
                                 portion                                  
                                       M.P.                               
                                          content                         
                                               mer  polymer               
                                                          polymer         
No.                                                                       
   Organic acid                                                           
          tion (%)                                                        
                 (%) -- Mw (× 10.sup.4)                             
                            -- Mw/-- Mn                                   
                                 (%)   (°C.)                       
                                          (%)  (%)  (%)   (%)             
__________________________________________________________________________
25 n-amyl 100    93  8.3    1.31 84    70 84   8    6     2               
   alcohol                                                                
26 n-butane thiol                                                         
          100    94  8.5    1.33 84    68 85   7    5     3               
27 Versatic                                                               
          100    94  8.1    1.32 84    69 83   9    5     3               
   acid *1                                                                
28 ethylene                                                               
          100    95  8.2    1.29 85    72 85   8    5     2               
   glycol                                                                 
   monbutyl                                                               
   ether                                                                  
29 diethylamino-                                                          
          100    95  7.7    1.27 85    71 83   10   5     2               
   ethanol                                                                
30 di-n-butyl-                                                            
          100    95  7.8    1.28 84    68 83   9    6     2               
   amine                                                                  
31 piperidine                                                             
          100    94  8.4    1.30 83    62 84   8    6     2               
32 tridecane-                                                             
           98    88  9.0    1.41 82    52 75   12   9     4               
   sulfonic acid                                                          
33 dodecyl-                                                               
           97    90  9.1    1.44 82    56 77   11   8     4               
   benzene-                                                               
   sulfonic acid                                                          
__________________________________________________________________________
 Note: *1 Carboxylic acid mixture produced by Shell Chemical Co. (Versatic
 10)                                                                      
 
    
     EXAMPLE 34 
     The experiment is practiced in quite the same manner as in Examples 25 to 33 except for using strontium dinonylphenoxide at the catalyst component (a). The results are shown in Table 7. 
     
                                           TABLE 7                                 
__________________________________________________________________________
Monomer conversion Polymer characteristics                                
Styrene                        Trans-                                     
conversion on                  linkage  Polymer composition               
     completion of                                                        
             Final             content at                                 
                                        Coupling   Butadiene              
                                                         Styrene          
     styrene butadiene                                                    
                   Molecular   butadiene                                  
                                        polymer                           
                                             Diblock                      
                                                   homo- homo-            
Example                                                                   
     polymerization                                                       
             conversion                                                   
                   weight, etc.                                           
                               portion                                    
                                     M.P.                                 
                                        content                           
                                             copolymer                    
                                                   polymer                
                                                         polymer          
No.  (%)     (%)   -- Mw (× 10.sup.4)                               
                          -- Mw/-- Mn                                     
                               (%)   (°C.)                         
                                        (%)  (%)   (%)   (%)              
__________________________________________________________________________
34   99      94    7.9    1.37 82    61 81   10    7     2                
__________________________________________________________________________
 
    
     EXAMPLES 35-43 AND COMPARATIVE EXAMPLES 4 AND 5 
     A pressure glass bottle of 700 ml volume which is internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next, as the catalyst components, 0.5 mmol of barium dinonyl phenoxide, the organic magnesium and the organic compound of lithium as shown in Table 8 are added in the amounts shown in the same Table, and further 0.89 mmol of triethylaluminum is added, followed by polymerization at 70° C. while stirring for 3 hours. At this point, a small amount of the polymerized solution is sampled for analysis. Then, 280 g of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, followed further by polymerization at 65° C. for 3 hours. Next, 0.67 mmol of purified and dried methylbenzoate is added and the reaction is carried out at 65° C. for 30 minutes. After the reaction, polymerization is stopped by addition of 1 ml of methanol and 0.3 parts by weight of BHT are added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The results are shown in Table 8. The analytical methods are the same as shown in Examples 25-33. 
     
         TABLE 8
  Monomer conversion    Styrene    Ex-  conversion  Polymer Characteristic
 s ample  Organic compound Polymerization on comple- Final  Trans-
 Polymer composition or Organic magnesium of lithium accelerator tion of
 buta-  linkage  Coupling Diblock Budadiene Styrene Comp.  Amount  Amount
  Amount Styrene diene Molecular content at  polymer co- homo- homo- Ex.
 added  added  added polymer- conver- weight, etc. butadiene M.P.*.sup.4
 content polymer polymer polymer No. name (mmol) Name (mmol) Name (mmol)
 ization (%) sion (%) --Mw (× 10.sup.4) --Mw/--Mn portion (%)
 (°C.) (%) (%) (%) (%)
   Ex.                  35 MAGALA-BEM*.sup.1 0.67 n- 0.67 -- 0 100 94 7.8
 1.35 84 69 83 9 5 3    butyl-    lithium 36 MAGALA-7.5E*.sup.2 0.67 n-
 0.67 -- 0 100 93 7.6 1.33 84 63 82  9 5 4    butyl-    lithium 37
 dibutyl*.sup.3 0.84 n- 0.33 -- 0  99 92 8.1 1.35 85 76 81 10 5 4
 magnesium  butyl-    lithium 38 dibutyl*.sup.3 0.67 n- 0.67 -- 0 100 94
 7.7 1.32 84 70 84  8 4 4  magnesium  butyl-    lithium 39 dibutyl*.sup.3
 0.50 n- 1.00 -- 0 100 90 8.3 1.34 81 55 84  8 4 4  magnesium  butyl-
 lithium 40 dibutyl*.sup.3 0.67 sec- 0.67 -- 0 100 95 7.9 1.33 83 63 83
 9 5 3  magnesium  butyl-    lithium 41 dibutyl*.sup.3 1.00 lithium 1.00
 -- 0 100 93 8.1 1.36 83 62 78 12 7 3  magnesium  iso-    propoxide 42
 dibutyl*.sup.3 0.67 sec- 0.67 tetra-   2.00 100 95 8.0 1.31 85 77 80 11
 6 3  magnesium  butyl-  hydro-    lithium  furan 43 dibutyl*.sup.3 0.67
 sec- 0.67 triethyl-   2.00 100 95 7.7 1.30 85 76 80 11 7 2  magnesium
 butyl-  amine    lithium Comp. Ex. 4 dibutyl*.sup.3 1.00 -- 0   -- 0 29
 62 2.9 1.99 83 32 -- -- -- --  magnesium 5 -- 0   n- 2.00 -- 0 77 52 3.6
 2.15 73 none -- -- -- --    butyl-    lithium
 Note:
 *.sup.1 produced by Texas Alkyl Co.; molecular structure: nC.sub.4 H.sub.
 MgC.sub.2 H.sub.5
 *.sup.2 produced by Texas Alkyl Co.; molecular structure: 7.5(n C.sub.4
 H.sub.9).sub.2 Mg(C.sub.2 H.sub.5).sub.3 Al; amount added shown in amount
 of magnesium component
  *.sup.3 produced by Lithium Corp.
 *.sup.4 measured by differential scanning calorimeter (DSC)
 
    
     EXAMPLES 44-49 
     A pressure glass bottle of 700 ml volume which is internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next, as the catalyst components, 0.5 mmol of barium dinonyl phenoxide, 0.67 mmol of dibutylmagnesium (produced by Lithium Corp., n-butyl : s-butyl=about 1 : 1) 0.67 mmol of sec-butyllithium and the organic aluminum or the organic zinc shown in Table 9 in the amounts shown in Table 9 were added, followed by polymerization at 70° C. while stirring for 3 hours. At this point, a small amount of the polymerized solution is sampled for analysis. Then, 280 g of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, followed further by polymerization at 65° C. for 3 hours. Next, 0.67 mmol of purified and dried methylbenzoate is added and the reaction is carried out at  65° C. for 30 minutes. After the reaction, reaction is stopped by addition of 1 ml of methanol and 0.3 parts by weight of BHT are added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The results are shown in Table 9. The analytical methods are the same as shown in Examples 25-33. 
     
                                           TABLE 9                                 
__________________________________________________________________________
              Monomer conversion                                          
                          Polymer characteristics                         
                                               Polymer composition        
              Styrene                                                     
                     Final            Trans-   Coupl-  Buta-              
                                                           Sty-           
              conversion on                                               
                     buta-            linkage  ing Di- dine               
                                                           rene           
Ex-                                                                       
   Catalyst system                                                        
              completion                                                  
                     diene            content at                          
                                               poly-                      
                                                   block                  
                                                       homo-              
                                                           homo-          
am-      Amount                                                           
              of styrene                                                  
                     conver-                                              
                          Molecular weight,                               
                                      butadiene                           
                                               mer copoly-                
                                                       poly-              
                                                           poly-          
ple      Added                                                            
              polymeriza-                                                 
                     sion etc.        portion                             
                                            M.P.                          
                                               content                    
                                                   mer mer mer            
No.                                                                       
   Name  (mmol)                                                           
              tion (%)                                                    
                     (%)  -- Mw (× 10.sup.4)                        
                                 -- Mw/-- Mn                              
                                      (%)   (°C.)                  
                                               (%) (%) (%) (%)            
__________________________________________________________________________
44 triisobutyl-                                                           
         0.89 100    95   7.8    1.33 84    65 84   9  5   2              
   aluminum                                                               
45 tri-n-                                                                 
         0.89 100    95   8.1    1.37 84    60 82  10  6   2              
   hexyl-                                                                 
   aluminum                                                               
46 tri-iso-                                                               
         0.89 100    94   8.3    1.31 84    62 82  10  6   2              
   propyl-                                                                
   aluminium                                                              
47 diethyl-                                                               
         0.59  96    91   8.0    1.41 82    51 78  12  7   3              
   aluminum                                                               
   mono-                                                                  
   hydride                                                                
48 diethylzinc                                                            
         1.34 100    90   8.1    1.40 83    56 72  14  10  4              
49 di-isobutyl-                                                           
         1.34 100    92   8.1    1.39 83    53 76  13  7   4              
   zinc                                                                   
__________________________________________________________________________
 
    
     EXAMPLES 50-57 
     A pressure glass bottle of 700 ml volume which is as internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next, as the catalyst components, 0.5 mmol of barium dinonyl phenoxide, 0.67 mmol of dibutylmagnesium (produced by Lithium Corp., n-butyl : s-butyl=about 1 : 1), 0.67 mmol of sec-butyllithium and 0.89 mmol of triethylaluminum were added, followed by polymerization at 70° C. while stirring for 3 hours. At this point, a small amount of the polymerized solution is sampled for analysis. Then, 280 g of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, followed further by polymerization at 65° C. for 3 hours. After the polymerization, the compound as shown in Table 10 is added as the terminal coupling agent in the amount shown in the same Table, and the reaction is carried out at 65° C. for one hour. After the reaction, reaction is stopped by addition of 1 ml of methanol and 0.3 parts by weight of BHT are added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The results are shown in Table 10. The analytical methods are the same as shown in Examples 25-33. 
     
                                           TABLE 10                                
__________________________________________________________________________
                  Monomer conversion                                      
                                  Polymer characteristics                 
                                                        Polymer           
Coupling agent    Styrene conversion                                      
                            Final             Trans-linkage               
                                                        Composition       
Ex-          Amount                                                       
                  on completion                                           
                            butadiene                                     
                                  Molecular   content at                  
                                                        Coupling          
ample        added                                                        
                  of styrene                                              
                            conversion                                    
                                  weight, etc.                            
                                              butadiene                   
                                                     M.P.                 
                                                        polymer           
No. Compound (mmol)                                                       
                  polymerization (%)                                      
                            (%)   -- Mw (× 10.sup.4)                
                                         -- Mw/-- Mn                      
                                              portion (%)                 
                                                     (°C.)         
                                                        content           
__________________________________________________________________________
                                                        (%)               
50  tetrachlorosilane                                                     
             0.50 100       92    13.5   1.31 84     68 84                
51  dimethyl-                                                             
             1.00 100       92     6.8   1.33 84     69 78                
    diethylsilane                                                         
52  tetrachlorotin                                                        
             0.50 100       94    12.1   1.29 83     65 84                
53  ethyl adipate                                                         
             0.50 100       92    12.7   1.27 83     63 80                
54  diphenyl  0.335                                                       
                  100       93     8.2   1.45 83     62 57                
    carbonate                                                             
55  diphenyl 0.50 100       93    10.1   1.27 83     64 82                
    carbonate                                                             
56  diphenyl 0.67 100       93    10.6   1.25 83     63 87                
    carbonate                                                             
57  diphenyl 1.34 100       92     9.4   1.39 82     57 72                
    carbonate                                                             
__________________________________________________________________________
 
    
     EXAMPLE 58 
     The experiment is practiced in quite the same manner as in Example 40 except for using isoprene as the conjugated diene monomer. The results are shown in Table 11. 
     
                                           TABLE 11                                
__________________________________________________________________________
Monomer conversion                                                        
Styrene            Polymer characteristics                                
conversion on                  1,4-Trans                                  
                                        Polymer composition               
     completion of                                                        
             Final             content at                                 
                                        Coupling   Isoprene               
                                                         Styrene          
     styrene isoprene                                                     
                   Molecular   isoprene polymer                           
                                             Diblock                      
                                                   homo- homo-            
Example                                                                   
     polymerization                                                       
             conversion                                                   
                   weight, etc.                                           
                               portion                                    
                                     M.P.                                 
                                        content                           
                                             copolymer                    
                                                   polymer                
                                                         polymer          
No.  (%)     (%)   -- Mw (× 10.sup.4)                               
                          -- Mw/-- Mn                                     
                               (%)   (°C.)                         
                                        (%)  (%)   (%)   (%)              
__________________________________________________________________________
58   100     89    8.7    1.37 89    42 81   9     7     3                
__________________________________________________________________________
 
    
     EXAMPLES 59-67 AND COMPARATIVE EXAMPLES 6 AND 7 
     A pressure glass bottle of 700 ml volume which is internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next as the catalyst components, the organic magnesium and the organic compound of lithium as shown in Table 12 are added in the amount shown in the same Table. At this point, small amount of the polymerized solution is sampled for analysis. Next, after addition of 0.15 mmol of bis(2-ethylhexyl)phosphate of lanthanum metal into the polymerized solution, 280 g of cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene into the polymerized solution, and polymerization is further carried out at 65° C. for 3 hours. Then, with addition of 0.67 mol of purified and dried methylbenzoate, the reaction is carried out at 65° C. for 30 minutes. After the reaction, polymerization is stopped with addition of 1 ml of methanol, and 0.3 parts by weight of BHT is added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The results are shown in Table 12. 
     The polymerization conversions of styrene and butadiene are determined by analysis according to gas chromatography, the molecular weight, molecular weight distribution and the composition of the polymers by analysis according to gel permeation chromatography (GPC) under the conditions in Example 1, the trans-1,4 linkage content at the butadiene portion in the polymer by analysis according to IR-spectrophotometer, calculation according to the Hampton method, and the melting point by analysis according to differential scanning calorimeter (DSC). 
     
         TABLE 12
  Monomer conversion    Styrene    Ex- Catalyst system conversion
 Polymer Characteristics ample  Organic compound Polymerization on
 comple- Final  Trans-  Polymer composition or Organic magnesium of
 lithium accelerator tion of buta-  linkage  Coupling Diblock Budadiene
 Styrene Comp.  Amount  Amount  Amount Styrene diene Molecular content at
  polymer co- homo- homo- Ex.  added  added  added polymer- conver-
 weight, etc. butadiene M.P.*.sup.4 content polymer polymer polymer No.
 name (mmol) Name (mmol) Name (mmol) ization (%) sion (%) --Mw (×
 10.sup.4) --Mw/--Mn portion (%) (°C.) (%) (%) (%) (%)
   Ex.                  59 MAGALA-BEM*.sup.1 0.67 n- 0.67 -- 0 100 91 9.6
 1.51 88 92 81 8 7 4    butyl-    lithium 60 MAGALA-7.5E*.sup.2 0.67 n-
 0.67 -- 0  90 89 9.2 1.55 88 93 79 8 9 4    butyl-    lithium 61
 dibutyl*.sup.3 0.84 n- 0.33 -- 0  96 94 10.1  1.53 89 96 79 9 8 4
 magnesium  butyl-    lithium 62 dibutyl*.sup.3 0.67 n- 0.67 -- 0 100 95
 9.5 1.49 88 92 80 10
   6 4  magnesium  butyl-    lithium 63 dibutyl*.sup.3 0.50 n- 1.00 -- 0
 100 97 8.9 1.52 85 74 83 8 6 3  magnesium  butyl-    lithium 64 dibutyl*.
 sup.3 0.67 sec- 0.67 -- 0 100 93 9.4 1.62 88 92 85 6 6 3  magnesium
 butyl-    lithium 65 dibutyl*.sup.3 1.00 lithium 1.00 --  0  98 97 9.0
 1.60 88 90 79 7 10  4  magnesium  iso-    propoxide 66 dibutyl*.sup.3
 0.67 sec- 0.67 tetra-   2.00 100 98 9.7 1.45 88 91 84 7 6 3  magnesium
 butyl-  hydro-    lithium  furan 67 dibutyl*.sup.3 0.67 sec- 0.67
 triethyl-   2.00 100 98 9.9 1.61 86 79 84 8 5 3  magnesium  butyl-
 amine    lithium Comp. Ex.  6 dibutyl*.sup.3 1.00 -- 0   -- 0  0 -- --
 -- -- --   -- --  magensium  butyl-    lithium  7 -- 0   n- 2.00 -- 0
 100 100
 Note:
 *.sup.1 produced by Texas Alkyl Co.; molecular structure: nC.sub.4 H.sub.
 MgC.sub.2 H.sub.5
 *.sup.2 produced by Texas Alkyl Co.; molecular structure: 7.5(n C.sub.4
 H.sub.9).sub.2 Mg(C.sub.2 H.sub.5).sub.3 Al; amount added shown in amount
 of magnesium component
 *.sup.3 produced by Lithium Corp.
 *.sup.4 measured by differential scanning calorimeter (DSC)
 
    
     EXAMPLES 68-74 
     A pressure glass bottle of 700 ml volume which is internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next, as the catalyst components, 0.67 mmol of dibutyl magnesium (produced by Lithium Corp., n-butyl : s-butyl=about 1 : 1), 0.67 mmol of sec-butyl lithium are added, followed by polymerization at 70° C. while stirring for 3 hours. At this point, small amount of the polymerized solution is sampled for analysis. Then, after addition of 0.15 mmol of bis(2ethylhexyl)phosphate of the rare earth metal shown in Table 13, 280 g of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, followed further by polymerization at 65° C. for 3 hours. Next, 0.67 mmol of purified and dried methylbenzoate is added and the reaction is carried out at 65° C. for 30 minutes. After the reaction, the reaction is stopped by addition of 1 ml of methanol and 0.3 parts by weight of BHT are added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The analytical methods are the same as shown in Examples 59-67. The results are shown in Table 13. 
     
                                           TABLE 13                                
__________________________________________________________________________
       Monomer conversion                                                 
                     Polymer characteristics                              
       Styrene                   Trans-                                   
       conversion on             linkage  Polymer composition             
Ex-    completion of                                                      
               Final             content at                               
                                          Coupling                        
                                               Diblock                    
                                                    Butadiene             
                                                          Styrene         
am-                                                                       
   Rare                                                                   
       styrene butadiene         butadiene                                
                                          polymer                         
                                               co-  homo- homo-           
ple                                                                       
   earth                                                                  
       polymerization                                                     
               conversion                                                 
                     Molecular weight, etc.                               
                                 portion                                  
                                       M.P.                               
                                          content                         
                                               polymer                    
                                                    polymer               
                                                          polymer         
No.                                                                       
   metal                                                                  
       (%)     (%)   -- Mw (× 10.sup.4)                             
                            -- Mw/-- Mn                                   
                                 (%)   (°C.)                       
                                          (%)  (%)  (%)   (%)             
__________________________________________________________________________
68 Ce  100     88    9.2    1.59 88    86 76   10   10    4               
69 Pr  100     79    8.2    1.57 83    61 72   12   11    5               
70 Nd  100     84    8.4    1.61 84    63 75   12    8    5               
71 Pm  100     82    7.9    1.73 82    56 71   11   13    5               
72 Sm  100     66    9.2    1.66 82    54 75   13   11    11              
73 Eu  100     87    9.5    1.69 81    44 73   14   14    9               
74 Gd  100     82    7.1    1.37 80    40 67   15   14    4               
__________________________________________________________________________
 
    
     EXAMPLES 75-83 
     Examples 68-74 are repeated except that the lanthanum metal salts of organic acids as shown in Table 14 are used as the organic acid salts of rare earth metals. The results are shown in Table 14. 
     
                                           TABLE 14                                
__________________________________________________________________________
           Monomer conversion                                             
                        Polymer characteristics                           
           Styrene                Trans-   Polymer composition            
           conversion on          linkage            Buta-                
Ex-        completion                                                     
                  Final Molecular weight,                                 
                                  content at                              
                                           Coupling                       
                                                Diblock                   
                                                     diene                
                                                          Styrene         
am-        of styrene                                                     
                  butadiene                                               
                        etc.      butadiene                               
                                           polymer                        
                                                co-  homo-                
                                                          homo-           
ple        polymeri-                                                      
                  conversion                                              
                        --Mw      portion                                 
                                        M.P.                              
                                           content                        
                                                polymer                   
                                                     polymer              
                                                          polymer         
No.                                                                       
   Organic acid                                                           
           zation (%)                                                     
                  (%)   (× 10.sup.4)                                
                             --Mw/--Mn                                    
                                  (%)   (°C.)                      
                                           (%)  (%)  (%)  (%)             
__________________________________________________________________________
75 ethylhexanoic                                                          
           100    92    9.3  1.62 88    91 75   9    11   5               
   acid                                                                   
76 Versatic acid*.sup.1                                                   
           100    90    9.3  1.67 88    90 78   8    9    5               
77 naphthenic acid                                                        
           100    91    9.5  1.71 87    83 74   10   10   6               
78 rosin acid                                                             
           100    87    8.5  1.77 87    85 74   10   10   6               
79 nonylphenol                                                            
           100    84    8.9  1.79 86    80 68   11   12   9               
80 decanethionic                                                          
           100    80    7.7  1.90 86    78 63   13   14   10              
   acid                                                                   
81 P.sub.1 *.sup.2                                                        
           100    96    8.6  1.61 88    91 80   8    9    3               
82 P.sub.2 *.sup.3                                                        
           100    96    8.8  1.61 88    93 80   8    9    3               
83 P.sub.3 *.sup.4                                                        
           100    95    8.5  1.58 88    94 81   9    7    3               
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 Note:                                                                    
 *.sup.1 Carboxylic acid mixture produced by Shell Chemical Co. (Versatic 
 10)                                                                      
 ##STR6##                                                                 
 ##STR7##                                                                 
 ##STR8##                                                                 
 
    
     EXAMPLES 84-91 
     A pressure glass bottle of 700 ml volume which is internally replaced with nitrogen gas and then stoppered is charged with 120 g of a cyclohexane solution containing 20 wt. % of styrene previously purified and dried. Next, as the catalyst components, 0.67 mmol of dibutylmagnesium, 0.67 mmol of sec-butyllithium are added, followed by polymerization at 65° C. while stirring for 3 hours. At this point, small amount of the polymerized solution is sampled for analysis. Then, after addition of 0.15 mmol of bis(2-ethylhexyl)phosphate of the rare earth metal shown in Table 15, 280 g of a cyclohexane solution containing 20 wt. % of purified and dried 1,3-butadiene is charged into the polymerized solution, followed further by polymerization at 65° C. for 3 hours. After polymerization, further the compound as shown in Table 15 is added as the terminal coupling agent in the amount shown in the same Table and the reaction is carried out at 65° C. for 1 hour. After the reaction, the reaction is stopped by addition of 1 ml of methanol and 0.3 parts by weight of BHT were added per 100 parts by weight of the polymer, followed by evaporation of the solvent to recover the polymer. The results are shown in Table 15. The analytical methods are the same as shown in Examples 59-67. 
     
                                           TABLE 15                                
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                  Monomer conversion                                      
                                  Polymer characteristics                 
                                                        Polymer           
Coupling agent    Styrene conversion                                      
                            Final            Trans-linkage                
                                                        composition       
Ex-          Amount                                                       
                  on completion                                           
                            butadiene                                     
                                  Molecular   content at                  
                                                        Coupling          
ample        added                                                        
                  of styrene                                              
                            conversion                                    
                                  weight, etc.                            
                                              butadiene                   
                                                     M.P.                 
                                                        polymer           
No. Compound (m mol)                                                      
                  polymerization (%)                                      
                            (%)   -- Mw (× 10.sup.4)                
                                         -- Mw/-- Mn                      
                                              portion (%)                 
                                                     (°C.)         
                                                        content           
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                                                        (%)               
84  tetrachlorosilane                                                     
             0.50 100       96    11.7   1.67 88     93 62                
85  dimethyl-                                                             
             1.00 100       94     6.9   1.75 88     93 51                
    diethylsilane                                                         
86  tetrachlorotin                                                        
             0.50 100       95    11.5   1.70 88     93 58                
87  ethyl adipate                                                         
             0.50 100       94    12.1   1.66 89     95 62                
88  diphenyl  0.335                                                       
                  100       95     8.9   1.69 88     93 54                
    carbonate                                                             
89  diphenyl 0.50 100       96    10.2   1.45 88     94 87                
    carbonate                                                             
90  diphenyl 0.67 100       97    11.6   1.46 89     96 85                
    carbonate                                                             
91  diphenyl 1.34 100       95     9.8   1.51 88     94 74                
    carbonate                                                             
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