Process for producing propylene block copolymer

Propylene is copolymerized with ethylene in solvent-free polymerization in two steps where a resinous polymer is produced in the first step and a rubbery polymer is produced in the second step over a Ziegler catalyst whose solid catalyst component has undergone preliminary polymerization of an .alpha.-olefin in the absence of an organoaluminum compound. The solid catalyst components is specified. Less sticky polymer powder is obtainable.

BACKGROUND OF THE INVENTION 
1. Technical Field 
This invention relates to a process for producing propylene block 
copolymers under the conditions where substantially no solvent is used in 
an improved yield, which polymers have high rigidity and high impact 
strength with good powder flowability. 
2. Related Art 
Crystalline polypropylene, while having excellent characteristics, of 
rigidity and heat resistance, had on the other hand the problem .of low 
impact strength, particularly low impact strength at a low temperature. 
As the method for improving this point, there have been already known a 
method of forming a block copolymer by polymerizing stepwise propylene and 
ethylene or another olefin (Japanese Patent Publications Nos. 11230/1968, 
16668/1969, 20621/1969, 24593/1974, 30264/1974, Japanese Laid-open Patent 
Publications Nos. 25781/1973, 115296/1975, 35789/1978 and 110072/1979). 
However, when propylene and ethylene are polymerized in two stages or 
multiple stages, although impact resistance may be improved, there ensues 
on the other hand the problem that polymers of low crystallinity are 
formed in a large amount, because the product contains copolymer portions. 
Also, for improvement of impact strength of a block copolymer, it has been 
generally practiced to increase an amount of a rubbery copolymer formed in 
the block copolymerization. However, formation of by-products may be 
increased, and the polymer particles tend to have increased tackiness with 
the increase of rubbery copolymers, whereby sticking between polymer 
particles or sticking of the polymer particles onto the device inner wall 
may occur, whereby it becomes frequently difficult to perform stable 
running of a polymer production device for a long term. 
More particularly, poor fluidity of the polymer particles due to sticking 
of polymer particles will present a serious problem to operation of a 
process wherein no solvent is used, such as, e.g. gas-phase 
polymerization. 
Accordingly, it has been desired to develop technology by which sticking of 
polymer particles is prevented when the content of a rubbery polymer is 
increased thereby to increase process stability. 
SUMMARY OF THE INVENTION 
The present inventors have studied intensively in order to solve the 
problems as mentioned above, and consequently found that the above 
problems can be solved by use of a specific catalyst whereby the present 
invention has been obtained. 
More specifically, the present invention presents a process for producing 
propylene block copolymers which comprises practicing Polymerization step 
(1) and Polymerization step (2) in the substantial absence of a solvent 
and in the presence of a catalyst which comprises Catalyst component (A) 
and Catalyst component (B) thereby to produce a propylene block copolymer 
which contains a rubbery copolymer of propylene which is a fraction of the 
propylene block copolymer soluble in xylene at 20.degree. C. in a quantity 
of 10 to 70% by weight of the block copolymer: 
Catalyst component (A) being a contact product of Sub-components (i), (ii) 
undergone contact with an .alpha.-olefin of 1 to 20 carbon atoms in the 
absence of an organometal compound of a metal of Groups I to III of the 
Periodic Table; 
Sub-component (i) being a solid catalyst component for a Ziegler catalyst 
comprising titanium, magnesium and a halogen atom as essential components, 
Sub-component (ii) being a silicon compound represented by a formula 
EQU R.sup.1 R.sup.2.sub.3-n Si(OR.sup.3).sub.n 
wherein R.sup.1 indicates a branched hydrocarbyl group of 3 to 20 carbon 
atoms, R.sup.2 which may be the same as or different from R.sup.1 
indicates a hydrocarbyl group of 1 to 20 carbon atoms, R.sup.3 which may 
be the same as or different from R.sup.1 and/or R.sup.2 indicates a 
hydrocarbyl group of 1 to 4 carbon atoms, and n is a number satisfying an 
equation 1.ltoreq.n.ltoreq.3, and 
Sub-component (iii) being an organometal compound of a metal of the Group I 
to III of the Periodic Table, and 
Catalyst component (B) being an organoaluminum compound; 
Polymerization step (1) being a process where propylene or a mixture of 
propylene with ethylene is polymerized in a single or a multiple step to 
form a propylene homopolymer or a propylene copolymer with ethylene of an 
ethylene content of no higher than 7% by weight in a quantity of 10 to 90% 
by weight of the total quantity of the block copolymer produced; and 
Polymerization step (2) being a process wherein a mixture of propylene with 
ethylene is polymerized in a single or multiple step in the presence of at 
least a part of the process product of the Polymerization step (1) to form 
a rubbery copolymer of propylene with ethylene of a proportion by weight 
of propylene to ethylene of 90/10 to 10/90 in a quantity of 90 to 10% by 
weight of the total quantity of the block copolymer produced. 
Polymerization of propylene together with ethylene into a block copolymer 
with the catalyst according to the present invention in the substantial 
absence of a solvent results in a propylene block copolymer having high 
rigidity and high impact strength in a high yield (per catalyst used). 
Also, according to the present invention, even when the weight of rubbery 
copolymer components may become much (e.g. 10% by weight or more), 
tackiness of polymer particles is little, and therefore the trouble in 
running operation which has been a problem in the prior art can be solved. 
Still further, the catalyst activity during the step where a rubbery 
component of a block copolymer is produced, namely the polymerization step 
(2), is high. Most of known catalysts may suffer from reduced catalyst 
activity when they are used in the step for producing a rubbery component 
of a block copolymer, and the catalyst in accordance with the present 
invention which is free of this disadvantage is advantageous for use in 
commercial production of block copolymers. 
It is also pointed out that use of a catalyst in accordance with the 
present invention will produce polymers endowed with improved powder or 
granulometric characteristics. Polymers produced by the present invention 
may have, for example, a bulk density of 0.45 g/cc or more, or 0.50 g/cc 
or more in sometime. 
DETAILED DESCRIPTION OF THE INVENTION 
[I] Catalyst 
The catalyst of the present invention comprises a combination of specific 
components (A) and (B). Here, the wording "comprises" does not mean that 
the components are limited only to those mentioned (namely, A and B), and 
does not exclude presence of other components compatible with or suited 
for the use of the components (A) and (B) in accordance with the present 
invention. 
Sub-component (i) 
The component (A) of the catalyst of the present invention is a contact 
product with an .alpha.-olefin in the substantial absence of an 
organometal compound of a metal of Groups I to III of the Periodic Table 
of a solid component obtained by contact of Sub-components (i), (ii) and 
(iii) with each other. Here, the wording "a solid component obtained by 
contact of Sub-components (i), (ii) and (iii) with each other" includes a 
solid component obtained by contact solely of the Sub-components (i), (ii) 
and (iii) and those containing any suitable additional components. 
The Sub-component (i) of the catalyst of the present invention is a solid 
component comprising titanium, magnesium and a halogen as the essential 
components. Here, the wording "comprising as the essential components" 
indicates that it can also contain other elements suited for the purpose 
than the three components mentioned, that these elements can exist in any 
desired compound suited for the purpose respectively, and also that these 
elements can also exist in the form mutually bonded together. Solid 
components comprising titanium, magnesium and a halogen are known per se. 
For example, those as disclosed in Japanese Laid-open Patent Publications 
Nos. 45688/1978, 3894/1979, 31092/1979, 39483/1979, 94591/1979, 
118484/1979, 131589/1979, 75411/1980, 90510/1980, 90511/1980, 127405/1980, 
147507/1980, 155003/1980, 18609/1981, 70005/1981, 72001/1981, 86905/1981, 
90807/1981, 155206/1981, 3803/1982, 34103/1982, 92007/1982, 121003/1982, 
5309/1983, 5310/1983, 5311/1983, 8706/1983, 27732/1983, 32604/1983, 
32605/1983, 67703/1983, 117206/1983, 127708/1983, 183708/1983, 
183709/1983, 149905/1984 and 149906/1984 may be employed. 
As the magnesium compound which is the magnesium source to be used in the 
present invention, magnesium dihalides, dialkoxymagnesiums, 
alkoxymagnesium halides, magnesium oxyhalides, dialkylmagnesiums, 
magnesium oxide, magnesium hydroxide, carboxylates of magensium, etc. are 
exemplified. Among these magnesium compounds, magnesium dihalides, 
particularly MgCl.sub.2, are preferred. 
As the titanium compound which is the titanium source, compounds 
represented by the formula 
EQU Ti(OR.sup.4).sub.4-n X.sub.n 
(wherein R.sup.4 is a hydrocarbyl group, preferably having about 1 to 10 
carbon atoms, X represents a halogen atom and n is an integer of 
0.ltoreq.n.ltoreq.4) and polymers of a titanium tetraalkoxide. Specific 
examples may include: 
titanium tetrahalides such as TiCl.sub.4, TiBr.sub.4 and the like; 
alkoxytitanium halides such as 
Ti(OC.sub.2 H.sub.5)Cl.sub.3, 
Ti(OC.sub.2 H.sub.5).sub.2 Cl.sub.2, 
Ti(OC.sub.2 H.sub.5).sub.3 Cl, 
Ti(O--iC.sub.3 H.sub.7)Cl.sub.3, 
Ti(O--nC.sub.4 H.sub.9)Cl.sub.3, 
Ti(O--nC.sub.4 H.sub.9).sub.2 Cl.sub.2, 
Ti(OC.sub.2 H.sub.5)Br.sub.3, 
Ti(OC.sub.2 H.sub.5)(OC.sub.4 H.sub.9).sub.2 Cl, 
Ti(O--nC.sub.4 H.sub.9).sub.3 Cl, 
Ti(O--C.sub.6 H.sub.5)Cl.sub.3, 
Ti(O--iC.sub.4 H.sub.9).sub.2 Cl.sub.2, 
Ti(OC.sub.5 H.sub.11)Cl.sub.3, 
Ti(OC.sub.6 H.sub.13)Cl.sub.3, and the like; 
and titanium tetraalkoxides such as 
Ti(OC.sub.2 H.sub.5).sub.4, 
Ti(O--iC.sub.3 H.sub.7).sub.4, 
Ti(O--nC.sub.3 H.sub.7).sub.4, 
Ti(O--nC.sub.4 H.sub.9).sub.4, 
Ti(O--iC.sub.4 H.sub.9).sub.4, 
Ti(O--nC.sub.5 H.sub.11).sub.4, 
Ti(O--nC.sub.6 H.sub.13).sub.4, 
Ti(O--nC.sub.7 H.sub.15).sub.4, 
Ti(O--nC.sub.8 H.sub.17).sub.4, 
Ti[OCH.sub.2 CH(CH.sub.3).sub.2 ].sub.4, 
Ti[OCH.sub.2 CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9 ].sub.4, and the like. 
TiCl.sub.4, Ti(OEt).sub.4, Ti(OBu).sub.4, and Ti(OBu)Cl.sub.3 are 
preferable. 
Polymers of a titanium tetraalkoxide may include those represented by the 
following formula: 
##STR1## 
Here, R.sup.6 14 R.sup.9 represent the same or different hydrocarbyl 
groups, preferably aliphatic hydrocarbyl group having 1 to 10 carbon atoms 
or aromatic hydrocarbyl groups, particularly aliphatic hydrocarbyl groups 
having 2 to 6 carbon atoms. n represents a number of 2 or more, 
particularly a number up to 20. The value of n should be desirably 
selected so that the polytitanate itself or as a solution can be provided 
in a liquid state for the contact step with other components. A suitable n 
selected in view of ease of handling may be about 2 to 14, preferably 2 to 
10. Specific examples of such polytitanates may include 
n-butylpolytitanate (n=2 to 10), hexylpolytitanate (n=2 to 10), 
n-octylpolytitanate (n=2 to 10), and the like. Among them, 
n-butylpolytitanate is preferred. 
It is also possible to use, as the titanium compound for the titanium 
source, a molecular compound obtained by reacting an electron donor as 
described below with a compound TiX'.sub.4 (where X' represents a 
halogen). Specific examples may include: 
TiCl.sub.4 .multidot.CH.sub.3 COC.sub.2 H.sub.5, 
TiCl.sub.4 .multidot.CH.sub.3 CO.sub.2 C.sub.2 H.sub.5, 
TiCl.sub.4 .multidot.C.sub.6 H.sub.5 NO.sub.2, 
TiCl.sub.4 .multidot.CH.sub.3 COCl, 
TiCl.sub.4 .multidot.C.sub.6 H.sub.5 COCl, 
TiCl.sub.4 .multidot.C.sub.6 H.sub.5 CO.sub.2 C.sub.2 H.sub.5, 
TiCl.sub.4 .multidot.ClCOC.sub.2 H.sub.5, 
TiCl.sub.4 .multidot.C.sub.4 H.sub.4 O, and the like. 
It is also possible to use, as the titanium compound for the titanium 
source, a titanocene compound, for example dicyclopentadienyldichloro 
titanium, dicyclopentadienyldimethyl titanium, bisindenyldichlorotitanium, 
and the like. 
Among these titanium compounds, preferable are: TiCl.sub.4, Ti(OEt).sub.4, 
Ti(OBu).sub.4, and Ti(OBu)Cl.sub.3. TiCl.sub.4 and Ti(OBu)4 are more 
prefered. 
As to the halogen source, it is a common practice to supply the halogen 
from the halide compounds of magnesium and/or titanium as described above, 
but it can be also supplied from non halogenating agents such as halogen 
compounds of aluminum, halogen compounds of silicon, halogen compounds of 
phosphorus, and the like. 
The halogen contained in the catalyst components may be fluorine, chlorine, 
bromine, iodine or a mixture of these, particularly preferably chlorine. 
The solid component to be used in the present invention can also comprise, 
in addition to the above essential components: a silicon compound such as 
SiCl.sub.4, CH.sub.3 SiCl.sub.3, and the like; a polymeric silicon 
compound which will be shown in detail hereinlater; an aluminum compound 
such as Al(OiC.sub.3 H.sub.7).sub.3, AlCl.sub.3, AlBr.sub.3, Al(OC.sub.2 
H.sub.5).sub.3, Al(OCH.sub.3).sub.2 Cl; and a boron compound such as 
B(OCH.sub.3).sub.3, B(OC.sub.2 H.sub.5).sub.3, B(OC.sub.6 H.sub.5).sub.3 ; 
WCl.sub.6 and MoCl.sub.5. 
These optional compounds may remain in the solid component as the 
components of silicon, aluminum and boron. 
Further, in preparing the solid sub-component (i), use can also be made of 
an electron donor as what is called "an inside donor". 
Examples of the electron donor or the inside donor which can be used for 
preparation of the solid component may include oxygen-containing electron 
donors such as alcohols, phenols, ketones, aldehydes, carboxylic acids, 
esters of an organic acid or an inorganic acid, ethers, acid amides, acid 
anhydrides, and the like; and nitrogen-containing electron donors such as 
ammonia, amines, nitriles, isocyanates, and the like. 
More specifically, there may be included: (a) alcohols having 1 to 18 
carbon atoms, such as methanol, ethanol, propanol, pentanol, hexanol, 
octanol, dodecanol, octadecyl alcohol, benzyl alcohol, phenylethyl 
alcohol, cumyl alcohol, isopropylbenzyl alcohol and the like; (b) phenols 
having 6 to 25 carbon atoms which may or may not have an alkyl group, such 
as phenol, cresol, xylenol, ethylphenol, propylphenol, cumylphenol, 
nonylphenol, naphthol and the like; (c) ketones having 3 to 15 carbon 
atoms, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, 
acetophenone, benzophenone and the like; (d) aldehydes having 2 to 15 
carbon atoms, such as acetaldehyde, propionaldehyde, octylaldehyde, 
benzaldehyde, tolualdehyde, naphthaldehyde and the like; (e) organic acid 
esters having 2 to 20 carbon atoms, such as methyl formate, methyl 
acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, 
cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valerate, 
ethyl stearate, methyl chloroacetate, ethyl dichloroacetate, methyl 
methacrylate, ethyl crotonate, ethyl cyclohexanecarboxylate, methyl 
benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, 
cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, methyl toluylate, 
ethyl toluylate, amyl toluylate, ethyl ethylbenzoate, methyl anisate, 
ethyl anisate, ethyl ethoxybenzoate, diethyl phthalate, dibutyl phthalate, 
diheptyl phthalate, .gamma.-butyrolactone, .alpha.-valerolactone, 
coumarine, phthalide, ethylene carbonate, cellosolve ethyl acetate, 
cellosolve isobutyrate and cellosolve ethyl benzoate, etc.; (f) inorganic 
acid esters, such as silicates and borate such as ethyl silicate, butyl 
silicate, phenyltriethoxysilane, methyl borate, ethyl borate, phenyl 
borate, etc.; (g) acid halides having 2 to 15 carbon atoms, such as acetyl 
chloride, benzoyl chloride, toluyloic chloride, anisic chloride, phthaloyl 
chloride, phthaloyl isochloride and the like; (h) ethers having 2 to 20 
carbon atoms, such as methyl ether, ethyl ether, isopropyl ether, butyl 
ether, amyl ether, tetrahydrofuran, anisole, diphenyl ether and the like; 
(i) acid amides, such as acetic amide, benzoic amide, toluyloic amide and 
the like; (j) amines, such as monomethylamine, monoethylamine, 
diethylamine, tributylamine, piperidine, tribenzylamine, aniline, 
pyridine, picoline, tetramethylethylenediamine and the like; and (k) 
nitriles, such as acetonitrile, benzonitrile, tolunitrile and the like. 
One or more of these electron donors can be used in preparing the solid 
catalyst component. Among them, preferred are organic acid esters, 
inorganic acid esters and organic acid halides, particularly preferably 
phthalic acid esters, silicates, phthalic acid halides and cellosolve 
acetate. 
The amounts of the above respective components used may be at any desired 
level, so long as the advantages inherent in the present invention can be 
attained, but, generally speaking, the following ranges are preferred. 
The amount of the titanium compound used may be within the range of 
1.times.10.sup.-4 to 1000, preferably 0.01 to 10, in terms of molar ratio 
relative to the amount of the magnesium compound used. When a compound as 
the halogen source is used, its amount used may be within the range of 
1.times.10.sup.-2 to 1000, preferably 0.1 to 100, in terms of a molar 
ratio relative to magnesium used, irrespectively of whether the titanium 
compound and/or the magnesium compound may contain a halogen or not. 
The amount of the silicon, aluminum or boron compound used may be within 
the range of 1.times.10.sup.-3 to 100, preferably 0.01 to 1, in terms of a 
molar ratio to the amount of the above magnesium compound used. 
The amount of the electron donor compound used may be within the range of 
1.times.10.sup.-3 to 10, preferably 0.01 to 5, in terms of a molar ratio 
relative to the amount of the above magnesium compound used. 
The solid Sub-component (i) for preparing the component (A) may be prepared 
from the titanium source, the magnesium source and the halogen source, and 
further optionally other components such as an electron donor according to 
methods mentioned below. 
(a) A method in which a magnesium halide optionally together with an 
electron donor is contacted with a titanium compound. 
(b) A method in which alumina or magnesia is treated with a phosphorus 
halide compound, and the product is contacted with a magnesium halide, an 
electron donor, and a titanium compound containing a halogen. 
(c) A method in which the solid component obtained by contacting a 
magnesium halide with a titanium tetraalkoxide and a polymeric silicon 
compound is contacted with a titanium halide compound and/or a silicon 
halide compound. 
As the polymeric silicon compound, those represented by the following 
formula are suitable: 
##STR2## 
wherein R is a hydrocarbyl group having about 1 to 10 carbon atoms, n is a 
degree of polymerization such that the viscosity of the polymeric silicon 
compound may be 1 to 100 centistokes. 
Among them, methylhydrogenpolysiloxane, 
1,3,5,7-tetramethylcyclotetrasiloxane, 
1,3,5,7,9-pentamethylcyclopentacycloxane, ethylhydrogenpolysiloxane, 
phenylhydrogenpolysiloxane, and cyclohexylhydrogenpolysiloxane are 
preferred. 
(d) A method in which a magnesium compound is dissolved in a titanium 
tetraalkoxide and an electron donor, and the solid component precipitated 
from the solution upon addition thereto of a halogenating agent or a 
titanium halide compound is contacted with a titanium compound. Examples 
of halogenating agents include silicon halides, aluminium halides and 
halogen compounds of phosphorus. 
(e) A method in which an organomagnesium compound such as Grignard reagent, 
etc. is reacted with a halogenating agent, a reducing agent, etc., and 
then the reaction product is contacted with an electron donor and a 
titanium compound. 
(f) A method in which an alkoxy magnesium compound is contacted with a 
halogenating agent and/or a titanium compound in the presence or absence 
of an electron donor. 
(g) A method in which a magnesium dihalide and a titanium tetraalkoxide 
and/or a polymer thereof are contacted, and subsequently contacted with a 
polymeric silicon compound is contacted. 
Among these methods, methods (c) and (d) are preferable. 
Contact of the three components can be effected in the presence of a 
dispersing medium. As the dispersing medium in that case, hydrocarbons, 
halogenated hydrocarbons, dialkylsiloxanes, etc. may be exemplified. 
Examples of hydrocarbons may include hexane, heptane, toluene, cyclohexane 
and the like; examples of halogenated hydrocarbons include n-butyl 
chloride, 1,2-dichloroethylene, carbon tetrachloride, chlorobenzene, etc.; 
and examples of dialkylpolysiloxane include dimethylpolysiloxane, 
methylphenylpolysiloxane and the like. 
Sub-component (ii) 
Sub-component (ii) for preparing the Component (A) is a silicon compound 
expressed by a formula 
EQU R.sup.1 R.sup.2.sub.3-n Si(OR.sup.3).sub.n 
wherein R.sup.1 is a branched hydrocarbyl group, R.sup.2 is a hydrocarbyl 
group which is the same as or different from R.sup.1, R.sup.3 is a 
hydrocarbyl group which is the same as or different from R.sup.1 and/or 
R.sup.2, and n is a number satisfying an equation 1.ltoreq.n.ltoreq.3. 
It is preferable that R.sup.1 has a branch at the carbon atom adjacent to 
the silicon atom. The branch may preferably be an alkyl group and 
cycloalkyl group. More preferably, the carbon atom adjacent to the silicon 
atom, namely .alpha.-carbon atom, is a secondary or tertiary carbon atom. 
Most preferably, the carbon atom connected with the silicon atom is a 
tertiary carbon atom. 
R.sup.1 may have 3 to 20, preferably 4 to 10, carbon atoms. 
R.sup.2 may have 1 to 20, preferably 1 to 10, most preferably 1 to 4, 
carbon atoms and may be in a branched or straight configuration. 
R.sup.3 may be an aliphatic hydrocarbyl group, and preferably is a linear 
aliphatic hydrocarbyl group of 1 to 4 carbon atoms. 
Specific examples may include: 
##STR3## 
(CH.sub.3).sub.3 CSi(CH.sub.3)(OCH.sub.3).sub.2, (CH.sub.3).sub.3 
CSi(HC(CH.sub.3).sub.2)(OCH.sub.3).sub.2, 
(CH.sub.3).sub.3 CSi(CH.sub.3)(OC.sub.2 H.sub.5).sub.2, 
(C.sub.2 H.sub.5).sub.3 CSi(CH.sub.3)(OCH.sub.3).sub.2, 
(CH.sub.3)(C.sub.2 H.sub.5)CHSi(CH.sub.3)(OCH.sub.3).sub.2, 
((CH.sub.3).sub.2 CHCH.sub.2).sub.2 Si(OCH.sub.3).sub.2, 
(C.sub.2 H.sub.5)(CH.sub.3).sub.2 CSi(CH.sub.3)(OCH.sub.3).sub.2, 
(C.sub.2 H.sub.5)(CH.sub.3).sub.2 CSi(CH.sub.3)(OC.sub.2 H.sub.5).sub.2, 
##STR4## 
(CH.sub.3).sub.3 CSi(OCH.sub.3).sub.3, (CH.sub.3).sub.3 CSi(OC.sub.2 
H.sub.5).sub.3, 
(C.sub.2 H.sub.5).sub.3 CSi(OC.sub.2 H.sub.5).sub.3, 
(CH.sub.3)(C.sub.2 H.sub.5)CHSi(OCH.sub.3).sub.3, 
(C.sub.2 H.sub.5)(CH.sub.3).sub.2 CSi(OCH.sub.3).sub.3, 
(C.sub.2 H.sub.5)(CH.sub.3).sub.2 CSi(OC.sub.2 H.sub.5)3. 
The preferable are those having R.sup.1 which is a branched chain 
hydrocarbyl group of 3 to 20 carbon atoms whose .alpha.-carbon is 
secondary or tertiary, more preferably those having R.sup.1 which is a 
branched hydrocarbyl group of 4 to 10 carbon atoms whose .alpha.-carbon is 
tertiary. 
Sub-component (iii) 
Sub-component (iii) for preparing a solid catalyst component (A) in 
accordance with the present invention is an organometal compound of a 
metal of the Group I to III of the Periodic Table. 
The compounds are organometal compounds and thus have at least one organic 
radical-metal bonding. The organic radical may typically be a hydrocarbyl 
group of 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. 
The remaining valence of the metal in question other than those satisfied 
by an organic radical, if any, can be satisfied by a hydrogen atom, a 
halogen atom, hydrocarbyloxy group of 1 to 10, preferably 1 to 6, carbon 
atoms, or the metal itself with an oxygen bridge such as 
##STR5## 
when the compounds are alkylaluminoxanes where R is a lower alkyl. 
Specific examples of such organometal compounds may include: (a) 
organolithium compounds, e.g. methyllithium, n-butyllithium, 
sec-butyllithium, tert-butyllithium and the like; (b) organomagnesium 
compounds, e.g. diethylmagnesium, ethylbutylmagnesium, dibutylmagnesium, 
dihexylmagnesium, hexylethylmagnesium, ethylmagnesium chloride, 
ethylmagnesium bromide, butylmagnesium chloride, tert-butylmagnesium 
bromide, and the like; (c) organozinc compounds, e.g. diethylzinc, 
dimethylzinc, dibutylzinc, and the like; (d) organoaluminum compounds, 
e.g. trimethylaluminum, triethylaluminum, triisobutylaluminum, 
tri-n-hexylaluminum, diethylaluminum chloride, diethylaluminum hydride, 
diethylaluminum ethoxide, ethylaluminum sesquichloride, ethylaluminum 
dichloride, methylaluminoxane, and the like. 
Among these, organoaluminum compounds including alkylaluminoxanes are 
preferable. Further examples of organoaluminum compounds may be found in 
the examples of organoaluminum compounds as the Component (B) which will 
be given hereinbelow. 
Preparation of the Component (A) 
The contacting conditions of the Sub-components (i)-(iii) and proportions 
can be as desired, so long as the advantages inherent in the present 
invention can be attained, but generally the following conditions are 
preferred. 
The quantitative ratio of the Sub-components (i) to (iii) can be any 
desired one, so long as the advantages inherent in the present invention 
can be attained, but generally preferred to be within the following 
ranges. 
The quantitative ratio of the Sub-component (i) to (ii) may be within the 
range of 0.01 to 1000, preferably 0.1 to 100, in terms of the atomic ratio 
(silicon/titanium) of the silicon of the Sub-component (ii) to the 
titanium component constituting the Sub-component (i). 
The Sub-component (iii) is used in an amount within the range of 0.01 to 
100, preferably 0.1 to 30, in terms of the atomic ratio of the metals 
{metal in the organometal compound (Sub-component 
(iii)/titanium(Sub-component (i)}. 
The contacting order and the contacting time of the Sub-components (i) to 
(iii) in preparing the component (A) of the present invention may be any 
desired one, so long as the advantages inherent in the present invention 
are attained. 
Specific orders of such contact may include those as shown below, where the 
symbol "+" indicates a contact between the components flanking the symbol, 
and a washing or rinsing processing can be interposed between the 
contacts. 
(a) {Sub-component (i)+Sub-component (ii)}+Sub-component (iii); 
(b) {Sub-component (i)+Sub-component (iii)}+Sub-component (ii); 
(c) Sub-component (i)+({(Sub-component (ii)+Sub-component 
(iii)}+{Sub-component (ii)+Sub-component (iii)}; 
(d) {(Sub-component (i)+Sub-component (iii)}+Sub-component (ii); and 
(e) Sub-component (i)+Sub-component (ii)+Sub-component (iii). 
The contact temperature may be about -50.degree. to 200.degree. C., 
preferably 0.degree. to 100.degree. C. As the contacting method, there may 
be employed a mechanical method wherein a rotating ball mill, a vibrating 
ball mill, a jet mill, a medium stirring pulverizer or the like is used 
and the method in which contact is effected with stirring under the 
presence of an inert diluent. As the inert diluent to be used, aliphatic 
or aromatic hydrocarbons and halohydrocarbons, polysiloxane, etc. may be 
exemplified. The contact can be effected in the presence of any additional 
compounds, provided that the advantages inherent in the present invention 
are not impaired, such as methylhydrogen polysiloxane, ethyl borate, 
aluminum triisopropoxide, aluminum trichloride, silicon tetrachloride, a 
titanium compound of a formula: Ti(OR).sub.4-n X.sub.n wherein n is a 
number of an equation 0.ltoreq.n.ltoreq.4, R is a hydrocarbyl group and X 
indicates a halogen atom, a tri-valent titanium compound, wolfram 
hexachloride, molybdenum pentachloride and the like. 
The catalyst component (A) in accordance with the present invention is such 
that the product of contact of the Sub-components (i), (ii) and (iii) has 
undergone contact with an .alpha.-olefin, in the substantial absence of an 
organometal compound of a metal of Group I to III of the Periodic Table. 
The expression "in the substantial absence" indicates that the contact 
product of Sub-components (i), (ii) and (iii) is washed with an inert 
solvent such as hydrocarbon repeatedly so that the washings will show no 
free organometal compound detected therein. 
When a titanium-containing solid catalyst component is contacted with an 
.alpha.-olefin to carry out the preliminary polymerization, it is a 
conventional practice to perform the preliminary polymerization in the 
presence of an organometal compound of a metal of Group I to III of the 
Periodic Table. 
In the present invention, however, the advantages inherent in the present 
invention would not be obtained at all if the preliminary polymerization 
is carried out in the presence of the organometal compound as evidenced in 
the Comparative Example given hereinlater. 
The reason why Component (A) which is obtained through the contact of the 
contact product of Sub-components (i)-(iii) with an .alpha.-olefin in the 
substantial absence of an organometal compound is advantageous in the 
present invention has not yet been fully elucidated, but analysis of 
Component (A) so obtained showed that Component (A) has a lower bulk 
density, a larger specific surface area upon determination by means of a 
porosimeter and a larger pore volume than similar prior solid products 
produced in the same way except for the contact with an .alpha.-olefin in 
the presence of a free organometal compound, whereby it is shown that 
Component (A) is porous in comparison with the prior solid products, and 
this nature of Component (A) is assumed to be one of the reasons for the 
advantage inherent in the present invention. 
Reaction conditions for the contact of the contact product of the 
Sub-components (i)-(iii) with an .alpha.-olefin may be any suitable ones 
as long as the advantages inherent in the present invention are attained, 
but following is preferable. 
The temperature may be -5.degree. to +200.degree. C., preferably 0.degree. 
to 100.degree. C. 
The contact may be performed in the absence or presence of an inert diluent 
such as an aliphatic or aromatic hydrocarbon under stirring. 
Examples of the .alpha.-olefin include those having 2 to 20 carbon atoms, 
preferably 2 to 10 carbon atoms, such as ethylene, propylene 1-butene, 
1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 
1-decene. 
The quantity of the .alpha.-olefin polymerized may be 0.001 to 500 grams, 
preferably 0.1 to 50 grams, per 1 gram of the contact product of the 
sub-components (i) to (iii). 
Component (B) 
The component (B) is an organoaluminum compound. Specific examples may 
include those represented by R.sup.5.sub.3-n AlX.sub.n or R.sup.6.sub.3-m 
Al(OR.sup.7).sub.m (wherein R.sup.5 and R.sup.6, which may be the same or 
different, are each hydrocarbyl groups having about 1 to 20 carbon atoms 
or hydrogen atom, R7 is a hydrocarbyl group, X is a halogen atom, n and m 
are respectively numbers of 0.ltoreq.n&lt;3, 0 &lt;m&lt;3). 
Specifically, there may be included (a) trialkylaluminums such as 
trimethylaluminum, triethylaluminum, triisobutylaluminum, 
trihexylaluminum, trioctylaluminum, tridecylaluminum, and the like; (b) 
alkylaluminum halides such as diethylaluminum monochloride, 
diisobutylaluminum monochloride, ethylaluminum sesquichloride, 
ethylaluminum dichloride, and the like; (c) dialkylaluminum hydrides such 
as diethylaluminum hydride, diisobutylaluminum hydride and the like; (d) 
aluminum alkoxides such as diethylaluminum ethoxide, diethylaluminum 
phenoxide, and the like. 
The organoaluminum compounds of (a) to (c) can be used in combination with 
alkylaluminum alkoxides, such as, for example, alkylaluminum alkoxides 
represented by the formula: R.sup.8.sub.3-a Al(OR.sup.9).sub.a (wherein 
1.ltoreq.a.ltoreq.3, R.sup.8 and R.sup.9, which may be either the same or 
different, are each hydrocarbyl groups having about 1 to 20 carbon atoms). 
For example, there may be included combinations of triethylaluminum with 
diethylaluminum ethoxide; of diethylaluminum monochloride with 
diethylaluminum ethoxide; of ethylaluminum dichloride with ethylaluminum 
diethoxide; and of triethylaluminum, diethylaluminum ethoxide and 
diethylaluminum chloride. 
The amount of the component (B) used may be 0.1 to 1000, preferably 1 to 
100, in terms of weight ratio of the component (B)/component (A). 
Component (C) (optional) 
The catalyst in accordance with the present invention comprises Component 
(A) and Component (B), and can contain another component which is 
compatible with the present invention as described hereinabove. 
One of such a compatible component is a boron alkoxide having a bond of the 
formula B--OR.sup.10, R.sup.10 being an aliphatic or aromatic hydrocarbyl 
group having about 1 to 20, preferably about 1 to 8 carbon atoms. The 
balance of the valence of boron is preferably satisfied with the same or 
different OR.sup.10 group, an alkyl group (preferably about C.sub.1 to 
C.sub.10), a halogen atom (preferably chlorine), or a cyclic hydrocarbyl 
group of about C.sub.6 to C.sub.10. 
Specific examples of such boron compounds may include: 
B(OCH.sub.3).sub.3, 
B(OC.sub.2 H.sub.5).sub.3, 
B(OC.sub.3 H.sub.7).sub.3, 
B(OiC.sub.3 H.sub.7).sub.3, 
B(O--nC.sub.4 H.sub.9).sub.3, 
B(OC.sub.6 H.sub.13).sub.3, 
B(OC.sub.6 H.sub.5).sub.3, 
B(OC.sub.6 H.sub.4 (CH.sub.3)).sub.3, 
B(OC.sub.2 H.sub.5).sub.2 Cl, 
B(OCH.sub.3).sub.2 Cl, 
(C.sub.2 H.sub.5)B(OC.sub.2 H.sub.5).sub.2, 
B(C.sub.6 H.sub.5)(OCH.sub.3).sub.2, 
B(OC.sub.4 H.sub.9)Cl.sub.2, and the like. 
Among them, preferable are B(OCH.sub.3).sub.3, B(OC.sub.2 H.sub.5).sub.3 
and B(O--nC.sub.4 H.sub.5).sub.3. 
The amount of the component (C) used may be within the range of 0.1 to 40, 
preferably 1 to 20, in terms of molar ratio relative to the titanium 
constituting the component (A). The optional component (C) can be used in 
such a way that it is added to polymerization. 
[II] Polymerization process 
The polymerization process conducted in the presence of the above-described 
catalyst components, Components (A), (B) and (C), Component (C) being 
optional, is conducted in multi-steps, and at least two steps, i.e. step 
(1) and step (2), two steps being preferred, and the order of step (1) and 
then step (2) being preferred. 
Both the steps (1) and (2) are conducted in the substantial absence of a 
solvent, and in such a way, as is found in the conventional block 
copolymer production, that the later step (2) is conducted in the presence 
of at least a part of the process product of the former step (1). 
Making up of a catalyst 
The catalysts in accordance with the present invention may be made up by 
contacting Components (A) and (B) or (A), (B) and (C) each other at once, 
or stepwisely or portion-wisely, within or outside a polymerization 
vessel. 
Components (A) and (B), and (C) when used, can be supplemented during 
polymerization and/or to one or each of the steps (i) and (ii). This is 
especially true to Component (B), and it can be supplemented at the step 
(ii). 
Step (1) polymerization 
The step (1) polymerization is a process wherein propylene as it is or in 
admixture with a small quantity of ethylene is contacted with a catalyst 
comprising Components (A) and (B) or Components (A), (B) and (C) at once, 
or step-wisely or portion-wisely, thereby to produce a homopolymer of 
propylene or a copolymer of propylene with ethylene of an ethylene content 
of no higher than 7% by weight, preferably no higher than 3.0% by weight, 
more preferably no higher than 0.5% by weight, in a quantity of 10 to 90% 
by weight, preferably 20 to 80% by weight, of the total polymer produced. 
The polymers produced in the step (1) which contain ethylene in excess of 
7% by weight will result in the total copolymers produced such that the 
bulk density is undesirably low and quantity of low crystalline byproduct 
polymers is considerably high. When the polymers produced in the step (1) 
comprise less than 10% by weight of the total polymer produced, quantity 
of the low crystalline by-product polymers in the final copolymer is 
increased, too. When the polymers produced in the step (1) comprise more 
than 90% by weight of the total polymer produced, on the other hand, no 
advantage inherent in the present invention such as improvement in impact 
strength of the polymer produced inherent in block copolymers of this 
nature nor improvement in the spiral flow of the polymers produced which 
is inherent in the present invention will be attainable. 
The step (1) of polymerization in accordance with the present invention may 
be conducted at a temperature of e.g. 30.degree. to 95.degree. C., 
preferably 50.degree. to 85.degree. C., and under a pressure of 1 to 50 
kg/cm.sup.2.G. It is preferable to conduct the step (1) in the presence of 
hydrogen gas or another molecular weight controlling agent so as to obtain 
the final polymer of a higher melt flow rate. 
Step (2) polymerization 
The later step polymerization is conducted, according to conventional 
production of propylene block copolymers, in the presence of at least 
portion of or preferably all of the product produced in the former step 
polymerization. 
More particularly and typically, a mixture of propylene with ethylene is 
further introduced in a single batch or portion-wisely into the 
polymerization vessel in which the step (1) polymerization has taken place 
or into another polymerization vessel to which the process product of the 
step (1) has been transferred, thereby to produce propylene/ethylene 
copolymers of the propylene/ethylene ratio by weight of 90/10 to 10/90, 
preferably 70/30 to 30/70. The copolymers produced in the step (2) of 
polymerization comprise the rest of the total polymer produced, namely 90 
to 10% by weight, preferably 80 to 20% by weight, of the total polymer 
produced. 
The step (2) polymerization is designed for producing elastomeric polymers, 
and another .alpha.-olefin such as 1-butene, 1-pentene or 1-hexene can 
optionally and additionally be copolymerized. 
The step (2) polymerization may be conducted at a temperature of e.g. 
30.degree. to 90.degree. C., preferably 50.degree. to 80.degree. C., and 
under a pressure of e.g. 1 to 50 kg/cm.sup.2.G. 
It is preferable to operate the former step (1) polymerization and the 
later step polymerization so that the gaseous components present at the 
end of the former step polymerization such as propylene gas or 
propylene/ethylene gas and hydrogen if used are purged from the 
polymerization before the later step polymerization is initiated. 
The later step polymerization is conducted in the presence of at least a 
portion of the product produced in the former step polymerization, which 
is still catalytically active, and the catalyst used for the former step 
polymerization is used for continuing polymerization in the later step 
polymerization. It is, however, possible to supplement Component (A), (B) 
and/or (C) upon necessity. 
The later step polymerization may be conducted in the absence of hydrogen 
or another molecular weight controlling agent, but it is possible to use 
such. 
Polymerization mode 
The process for producing the copolymer according to the present invention 
can be practiced according to any of the batch-wise mode, the continuous 
mode and the semibatch-wise mode. These polymerization modes may be 
practiced by a method in which polymerization is carried out with the 
monomer used itself as a polymerization medium or dispersant, a method in 
which polymerization is carried out in gaseous monomers without use of any 
polymerization medium added, or a method in which polymerization is 
carried out in combination of these. 
A preferable polymerization method is such that polymerization is carried 
out in the atmosphere of gaseous monomers wherein a fluidized bed of the 
particles of the polymer produced is utilized or the particles of the 
polymer produced are agitated in the polymerization vessel. 
[III] Propylene block copolymers produced 
The propylene block copolymers produced in the substantial absence of a 
solvent in accordance with the present invention comprise a rubbery 
polymer of propylene in a quantity of 10 to 70% by weight, preferably 20 
to 70% by weight, more preferably 35 to 60% by weight. The "rubbery 
polymer of propylene" means a fraction of polymer (of the block copolymer) 
which is soluble in xylene at 20.degree. C. 
The present invention is concerned with production of propylene block 
copolymers. It should be understood that the wording "block copolymer" 
does not necessarily mean (a) a block copolymer of an ideal state such 
that the block formed in the step (1) and the block formed in the step (2) 
are in the same and common molecule chain, but include as is conventional 
in the art those which are (b) mixtures of the polymers formed in each 
step and those which are mixtures in any proportion of the ideal block 
copolymer (a) and the mixture of the polymers (b). 
[IV] Experimental Examples

EXAMPLE-1 
[Preparation of component (A)] 
Into a flask thoroughly purged with nitrogen was introduced 200 ml of 
dehydrated and deoxygenated n-heptane, and subsequently 0.1 mol of 
MgCl.sub.2 and 0.2 mol of Ti(O--nC.sub.4 H.sub.9).sub.4 and the reaction 
was carried at 95.degree. C. for 2 hours. After completion of the 
reaction, the temperature was lowered to 40.degree. C., followed by 
addition of 12 ml of methylhydropolysiloxane (of 20 centistokes) and the 
reaction was carried out for 3 hours. The solid product formed was washed 
with n-heptane. 
Subsequently into a flask thoroughly purged with nitrogen was introduced 50 
ml of n-heptane purified similarly as described above, and the solid 
product synthesized above was introduced in an amount of 0.03 mol as 
calculated on Mg atom. Then, a mixture of 25 ml of n-heptane with 0.05 mol 
of SiCl.sub.4 was introduced into the flask at 30.degree. C. over 30 
minutes, and the reaction was carried out at 70.degree. C. for 3 hours. 
After completion of the reaction, the product was washed with n-heptane. 
A mixture of 25 ml of n-heptane with 0.003 mole of phthaloyl chloride was 
added to the flask at 90.degree. C. for 30 minutes, and the reaction was 
carried out at 95.degree. C. for 1 hour. After the reaction, the solid 
product was washed with n-heptane, and 5 ml of SiCl.sub.4 and 80 ml of 
n-heptane were then added thereto and the reaction was carried out at 
90.degree. C. for 4 hours. After the reaction, the solid product was 
washed with n-heptane. The solid thus obtained was found to contain 1.78% 
by weight of titanium. This was used as the Sub-component (i). 
Into a flask amply purged with nitrogen was introduced 80 ml of amply 
purified n-heptane, and then 5 g of the solid product obtained above, 
Sub-component (i), was introduced. Next, 2.0 ml of (CH.sub.3).sub.3 
CSi(CH.sub.3)(OCH.sub.3).sub.2 as the Sub-component (ii), and 4.5 g of 
triethylaluminum as the Sub-component (iii) were respectively introduced 
and contacted at 30.degree. C. for 2 hours. After completion of the 
contact, the product was amply washed with n-heptane to provide a solid 
product. The washing with n-heptane was conducted so that no free 
organoaluminum compound was detected in the washings. 
The solid product obtained was then subjected to contact with propylene. 
Into a vessel of capacity of 1.5 liter equipped with agitation means were 
added 400 ml of amply purified n-heptane, the solid product and then 60 ml 
of hydrogen gas. Introduction into the vessel of propylene was started at 
20.degree. C. and stopped after 1 hour. The solid product thus obtained 
was amply washed with n-heptane to give the Component (A). The quantity of 
propylene polymerized was 10.3 g per 1 g of the solid product. 
[Copolymerization of propylene] 
According to the process disclosed in Japanese Patent Publication No. 
33721/1986, copolymerization of propylene was carried out wherein a 
horizontal biaxial gas phase polymerization vessel of 13-liter volume was 
used. 
After replacement of the polymerization vessel inside with amply purified 
nitrogen, 400 g of an amply dehydrated and deoxygenated polymer carrier 
was added. Subsequently, 500 mg of triethylaluminum as the component (B) 
and 820 mg of the above synthesized component (A) were introduced. In the 
polymerization step (1), after introduction of 1000 ml of hydrogen, at a 
temperature controlled to 75.degree. C., propylene was introduced at a 
constant rate of 1.3 g/min. The stirring rotation of the polymerization 
vessel was 350 r.p.m. The polymerization temperature was maintained at 
75.degree. C. and, after 3 hours and 40 minutes, introduction of propylene 
was stopped. Polymerization was continued at 75.degree. C., and when the 
polymerization pressure became 1 Kg/cm.sup.2 G, a small amount of the 
polymer sample was collected. 
Then, 500 ml of H.sub.2 was added to initiate the second stage 
polymerization. The second stage polymerization (the polymerization step 
(2)) was carried out by introducing 0.59 g/min. of propylene and 0.40 
g/min. of ethylene respectively at constant rates at 70.degree. C. for 1 
hour and 36 minutes. Introduction of propylene and ethylene was stopped, 
and polymerization under the residual pressure was carried out until the 
polymerization pressure became 1 Kg/cm.sup.2 G. After completion of 
polymerization, the polymer was taken out after purging to give 381 g of a 
polymer. The polymer formed had an MFR of 8.2 g/10 min., a polymer bulk 
density (B.D.) of 0.43 g/cc, and a polymer falling speed of 5.7 sec. The 
weight of the rubbery copolymer was 23.6% by weight. No polymer adhesion 
to the polymerization vessel was found, and the intermediate polymer 
sampled had an MFR of 18.3 g/10 min. 
The "polymer falling speed" means a time required for dropping 50 g of a 
polymer powder from an opening of 1.0 cm.sup.2. 
EXAMPLE-2 
[Preparation of component (A)] 
As in Example-1, MgCl.sub.2, Ti(O--nC.sub.4 H.sub.9).sub.4 and 
methylhydropolysiloxane were caused to react to form a solid product, 
which was washed with n-heptane. 
Into a flask purged with nitrogen gas were added 50 ml of n-heptane 
similarly purified and 0.03 mole of the above solid product. A mixture of 
25 ml of n-heptane with 11.6 ml of SiCl.sub.4 was added to the flask at 
30.degree. C. over 30 minutes, and caused to react at 90.degree. C. for 1 
hour. After the reaction, the solid product obtained was washed with 
n-heptane. 
To the solid product obtained in the flask were then added 2.4 ml of 
(CH.sub.3).sub.3 CSi(CH.sub.3)(OCH.sub.3).sub.2 as the Sub-component (ii) 
and 6.0 g of triethylaluminum as the Sub-component (iii) for contact at 
30.degree. C. for 2 hours. After the contact, the solid product formed was 
amply washed with n-heptane. The washing with n-heptane was conducted so 
that no free organoaluminum compound was detected in the washings. 
The solid product thus obtained was subjected to contact with propylene as 
in Example-1. The contact temperature was, however, changed from 
20.degree. C. to 30.degree. C. The quantity of propylene polymerized was 
10.8 g per 1 g of the solid product. 
[Copolymerization of propylene] 
The procedure as set forth in Example-1 for copolymerization of propylene 
was followed except for the polymerization times for the steps (1) and (2) 
were changed respectively to 3 hours and 10 minutes and 1 hour and 50 
minutes. 380 g of a polymer were obtained, which had MFR of 7.3 g/10 min, 
bulk density of 0.44 g/cc, polymer falling speed of 6.2 sec., and rubbery 
copolymer content of 35.2% by weight. No polymer adhesion to the 
polymerization vessel was found. 
EXAMPLE-3 
[Preparation of Component (A)] 
As in Example-1, the sub-components (i) to (iii) were caused to contact to 
form a solid product, which was subjected as in Example-1 to contact with 
propylene to provide Component (A) which had propylene polymerized in a 
quantity of 11.3 g per 1 g of the solid product. 
[Copolymerization of propylene] 
The procedure as set forth in Example-1 for copolymerization of propylene 
was followed except for the polymerization times for the steps (1) and (2) 
were changed respectively to 1 hour and 58 minutes and 3 hours and 49 
minutes and 77 mg of B(OCH.sub.3).sub.3 were added at the beginning of the 
step (2). 381 g of a polymer were obtained, which had MFR of 6.1 g/10 min, 
bulk density of 0.43 g/cc, polymer falling speed of 5.5 sec., and rubbery 
copolymer content of 57.8% by weight. No polymer adhesion to the 
polymerization vessel was found. 
EXAMPLE-4 
[Preparation of Component (A)] 
As in Example-2, the Sub-components (i) to (iii) were caused to contact to 
form a solid product, which was subjected as in Example-2 to contact with 
ethylene to provide Component (A) which had ethylene polymerized in a 
quantity of 9.7 g per 1 g of the solid product. 
[Copolymerization of propylene] 
The procedure as set forth in Example-1 for copolymerization of propylene 
was followed. 379 g of a polymer were obtained, which had MFR of 7.9 g/10 
min, bulk density of 0.41 g/cc, polymer falling speed of 6.1 sec., and 
rubbery copolymer content of 23.8% by weight. No polymer adhesion to the 
polymerization vessel was found. 
COMATIVE EXAMPLE-1 
[Preparation of Component (A)] 
As in Example-1, the Sub-components (i) to (iii) were caused to contact to 
form a solid product, which was subjected to contact with propylene as in 
Example-1 except for the use of 1.5 g of triethylaluminum at the contact 
with propylene to provide Component (A). 
[Copolymerization of propylene] 
The procedure as set forth in Example-1 for copolymerization of propylene 
was followed. 380 g of a polymer were obtained, which had MFR of 9.9 g/10 
min, bulk density of 0.25 g/cc, and rubbery copolymer content of 23.5% by 
weight. No determination of polymer falling speed was possible since no 
falling took place. Remarkable polymer adhesion to the polymerization 
vessel was found. 
EXAMPLES 5 TO 7 
The procedure for preparing Component (A) set forth in Example-1 was 
followed except for the quantity of propylene polymerized at the 
preliminary polymerization step changed to those set forth in Table-1 
given hereinbelow. The procedure for the copolymerization of propylene set 
forth in Example-1 was followed except for the polymerization time which 
was changed, in Examples 6 and 7, to 3 hours and 30 minutes for the 
step(1) and to 1 hour and 50 minutes for the step (2). 
The results obtained are set forth in Table -1. 
TABLE 1 
__________________________________________________________________________ 
Polypropylene (pp) 
at preliminary Rubbery 
polymerization 
Polymer polymer 
Polymer 
Falling 
Example 
(g .multidot. pp/g. solid 
formed 
MFR (% by 
B.D. speed 
No. component) 
(g) (g/10 min.) 
weight) 
(gg/cc) 
(sec.) 
__________________________________________________________________________ 
5 1.1 381 8.0 23.8 0.44 5.4 
6 0.13 382 7.6 30.1 0.43 5.8 
7 0.002 380 7.7 29.8 0.44 5.3 
__________________________________________________________________________ 
EXAMPLE 8 
The procedure for preparing Component (A) set forth in Example-2 was 
followed except for the quantity of propylene polymerized at the 
preliminary polymerization step changed to 0.003 g per g of the solid 
component. The procedure for polymerization of propylene was followed 
except for the polymerization time changed to 2 hours and 56 minutes for 
the step (1) and to 2 hours and 33 minutes for the step (2). 
383 g of a polymer was obtained, which had MFR of 6.9 g/10 min., a polymer 
bulk density (B.D.) of 0.43 g/cc, and polymer falling speed of 6.1 sec. 
The quantity of a rubbery polymer was 39.9 % by weight. 
Comparative Example-2 
The procedure for preparing Component (A) set forth in Example-1 was 
followed except for the preliminary polymerization which was not 
conducted. The procedure of copolymerization of propylene set forth in 
Example-1 was followed. 
380 g of a polymer was obtained, which had MFR of 8.4 g/10 min., a polymer 
B.D. of 0.38 g/cc, and a polymer falling speed of 7.9 sec. The quantity of 
a rubbery polymer was 24.4 % by weight. 
COMATIVE EXAMPLE-3 
The procedure for preparing Component (A) set forth in Example-1 except for 
the use of triethylaluminum for the preliminary polymerization in an 
amount of 2.5 g. The quantity of polypropylene at the preliminary 
polymerization was 0.11 g per g of the solid component. The procedure for 
copolymerization of propylene set forth in Example-1 was followed. 
377 g of a polymer was obtained, which had MFR of 10.1 g/10min., a polymer 
B.D. of 0.28 g/cc and a polymer falling speed which was not determinable 
due to non-falling.