Patent Publication Number: US-3880793-A

Title: Emulsifiers for emulsion polymerization of vinyl monomers

Description:
United States Patent 1191 Nakayama 1 Apr. 29, 1975 l l EMULSIFIERS FOR EMULSION POLYMERIZATION OF VINYL MONOMERS [75] Inventor: Yasuhara Nakayama.Hiratsuka.  
 Japan [73] Assignee: Kansai Paint Company Limited, Hyogo. Japan [22] Filed: Mar. 30, 1972 [21] Appl. No.: 239.733  
 [52] U.S. Cl.. 260/29.6 RW; 252/356. 260/296 BE; 260/296 R; 260/296 WB; 260/297 UA;  
 260/297 UP; 260/297 W; 260/95 R [51] Int. C1...... 301i 17/52; C08d 3/04; COSd 1/09; C08f 1/13 158] Field of Search ..260/29.6 MH. 2.96 XA, 260/297 W, 29.7 UP, 78.4 D. 29.7 H, 95 R. 260/296 R. 29.6 RW, 29.6 BE, 29.6 WB.  
 3.434.989 3/1969 Fantl et al 260/297 H 3.511.816 5/1970 Dickakian 260/784 1) 3.532.663 10/1970 Nicks ct al 260/342 3.609.110 9/1971 Kumanotani 260/297 H 3.637.565 1/1972 Shectz 260/297 H 3.654.203 4/1972 Daimer et a1 260/297 H 3.689.446 9 1972 Furuya m 211 260/297 H OTHER PUBLICATIONS Alfrey e1; 31.. High Polymers. V01. Vlll. pp. 81-83. (Interscience. 1952) [OD 281 P6A5c] Blackley. High Polymer Lactices, Vol. 1. pp. 268-274. (Applied Science Pub. Ltd.. London. 1966) [TSl890 B54] Primary Examiner--Melvin Goldstein Assistant E.\&#39;uminer-T. DeBenedictis, Sr. Armrney. Agent, or Firm-Larson. Taylor and Hinds l5 7] ABSTRACT An emulsifier for emulsion polymerization of a vinyl monomer comprises an addition product. neutralized with a base. of a butadiene polymer having a number average molecular weight of 200 to 40.000 and at least one of maleic acid and maleic anhydride. said addition product having an acid value of 20 to 350&#39;. and a method for polymerizing a vinyl monomer in an aqueous medium. characterized in that the above emulsifier is used for the polymerization.  
 2 Claims, No Drawings EMULSIFIERS FOR EMULSION POLYMERIZATION OF VINYL MONOMERS This invention relates to an emulsifier for emulsion polymerization of vinyl monomers, more particularly to a high molecular weight emulsifying agent for emulsion polymerization of vinyl monomers and a method for polymerizing vinyl monomers in aqueous medium in the presence of said emulsifying agent to produce vinyl polymer emulsions. Further the present invention pertains to aqueous emulsion of vinyl polymers useful as a vehicle for paints. adhesive. etc.  
  In general. emulsion polymerization of vinyl monomers has mainly been conducted using an emulsifying agent of a low molecular weight. When the polymer emulsion obtained by the above method is employed as a coating composition, however, the coating film obtained therefrom will be poor in water resistance. It has been proposed, on the other hand, to carry out the emulsion polymerization of vinyl monomers in the presence of a high molecular weight emulsifying agent having a hydrophilic side chain bonded ton an oleophilic main chain, such as polyacrylic acid, polymethacrylic acid, polyvinyl pryidine, etc. However, no re port has been made yet as to the use of the resultant emulsion as a coating composition and as to the characteristics of the coating film obtained therefrom.  
  An object of the invention is to provide a novel kind of a high molecular weight emulsifying agent for emulsion polymerization of vinyl monomers.  
 Another object of the invention is to provide a method for emulsion polymerization of vinyl monomers using a high molecular weight emulsifying agent, the resultant polymer emulsion thereby obtained being useful as vehicles for paints. adhesives and compositions for resin treatment.  
  Another object of the invention is to provide an aqueous emulsion of vinyl polymers capable of producing a coating film having a high order of hardness. water resistance and mechanical strengths with a smooth continuous surface.  
  These and other objects and advantages of the inven tion will be apparent from the following description.  
  The emulsifier of the present invention comprises an addition product. neutralized with a base, of a butadiene polymer having a number average molecular weight of 200 to 40.000 and at least one of maleic acid and maleic anhydride, said addition product having an acid value of to 350.  
  According to the researches of the present inventors it has been found that the above specific emulsifying agent, i.e., maleinized butadiene polymer, can be employed efficiently for emulsion polymerization ofa certain kind of vinyl monomers and that the aqueous emulsion ofvinyl polymers obtained by using the above emulsifier of the invention can be effectively used as a vehicle for paint to produce a glossy coating film having a high order of hardness, water resistance and mechanical strengths with a smooth continuous surface free from undesired tackiness. The reason why such an excellent coating film can be produced from the polymer emulsion obtained by using the above emulsifier of the present invention is attributable to tie fact that the molecules of the maleinized butadiene polymer used as an emulsifier and contained in the resultant aqueous emulsion of vinyl polymers will react with each other to form a three-dimensional network structure during film forming step. Further. the polymer emulsion is so excellent in pigment dispersibility that the pigment used never separates therefrom during film-forming step, making it possible to obtain a coating film having excellent gloss. The polymer emulsion obtained by the present invention is, further. useful as an adhesive and composition for resin treatment.  
  The butadiene polymer used as a starting material for producing the emulsifier of the invention includes homopolymers of butadiene, copolymers of butadiene with other copolymerizable monomers and modified products of these homopolymers and copolymers. The homopolymer of butadiene polymer can have any structure of 1,2-vinyl bond, trans 1,4-bond, cis 1,4- bond and mixture thereof. Particularly, polybutadiene containing more than 30% of 1,2-vinyl bond is preferable. When an emulsion polymerization is carried out using the emulsifying agent of the invention obtained by maleinization of a polybutadiene containing such a large amount of l,2-vinyl bond, graft polymerization of the vinyl monomer with the maleinized butadiene polymer occurs effectively during the polymerization step, whereby the coating film obtained from the resultant polymer emulsion can be cured sufficiently without using curing agent to produce a cured film having higher order of water resistance.  
  The copolymers of butadiene are those containing at least 10 wt.%. preferably at least 40 wt.&#39;7( of butadiene. The monomers to be copolymerized with butadiene include, for example, olefins having 2 to 6 carbon atoms&#34;, dienes such as isoprene. chloroprene. cyclopentadiene. etcx, acrylic acid. methacrylic acid and alkyl (C, to C esters thereof; styrene compounds such as styrene. a-methyl styrene, vinyl toluene, etc.; and acrylonitrile and methacrylonitrile.  
  The modified products of the homopolymer and copolymer of butadiene include, for example, partially hydrogenated butadiene polymers, cyclized butadiene polymers, hydroxyl butadiene polymers and epoxidized butadiene polymers. It is preferable that the modified butadiene polymer retains more than 60% of the double bond contained in the original butadiene polymer.  
  The butadiene polymers used in the invention are those having a number average molecular weight of 200 to 40,000. When the number average molecular weight thereof is less than 200. the emulsifying agent obtained therefrom fails to produce a vinyl polymer emulsion having a good storage stability and capable of producing a coating film having excellent properties. ln the case ofthe butadiene polymers having a number average molecular weight of more than 40,000, the viscosity thereof is too high to effect the subsequent maleinization reaction. Preferable number average molecular weight of the butadiene polymer is in the range of 500 to 10,000.  
  In the invention the butadiene polymer is maleinized with maleic acid and/or anhydride thereof to produce the emulsifier of the invention, i.e., an addition product of both compounds. The amount of maleic acid or anhydride thereof used may vary over a wide range in accordance with a kind of butadiene polymer, but it is necessary to use maleic acid or anhydride thereof in an amount sufficient to produce a maleinized butadiene polymer having an acid value ranging from 20 to 350. Usually such amount is in the range of 1.7 to 200 weight parts, preferably 3.5 to lOO weight parts, based on weight parts of the butadiene polymer. The maleinization reaction can be carried out with stirring in an inert gas atmosphere. using an organic solvent, if desired. Examples of the solvents are aromatic hydrocarbons such as benzene, toluene, xylene, etc., ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc, esters such as ethyl acetate. methyl acetate, butyl acetate, etc., ethers such as dioxane, tetrahydrofuran, dipropyl ether, etc. Preferable reaction temperature is in the range of 150 to 250C. The reaction usually is completed within 0.5 to 48 hours.  
  The addition product of butadiene polymer and maleic anhydride is then subjected to a ring-opening reac tion conventional in the art, using water, alcohols or amines. The use of water results in dicarboxylic acid compounds, alcohols in half estters and amines in half amides. Alcohols used are, for example, aliphatic monohydric alcohols having I to [8 carbon atoms, ethylene glycol, propylene glycol, polyethylene glycol having a molecular weight of not more than 1500 and polypropylene glycol having a molecular weight of not more than 2000, and amines used include, for example, methyl amine, ethyl amine, dimethyl amine and diethyl amine.  
  The acid value of the resultant addition product should be in the range of to 350. The addition product having a low acid value less than 20 fails to display sufficient effect as an emulsifier, while that of a high acid value more than 350 results in the production of a coating film having poor water resistance. Preferable acid value thereof is in the range of 20 to 200.  
  The addition product is neutralized with a base to produce emulsifying agent of the invention. The base used includes, for example, ammonia, alkali metal hydroxides, alkali metal oxides, alkali metal carbonates, alkali metal bicarbonates, and amines such as methyl amine, ethyl amine, propyl amine, butyl amine, stearyl amine. methanol amine and like primary amines, dimethyl amine, diethyl amine, methyl ethyl amine, diethanol amine and like secondary amines, and trimethyl amine, triethyl amine, tricthanol amine, morphorine and like tertiary amines,  
  In the invention the addition product neutralized with a base is useful as an emulsifying agent for emulsion polymerization of hydrophobic vinyl monomers having a Q value of at least 0.1 determined by Q-e scheme. The Qe scheme is a theory representing an addition reaction velocity constant of a monomer with a radical, formulated by Alfrey and Price in [947, and &#34;Q value is a constant showing the general reactivity of the monomer in question and increases as reactivity of the monomer with a radical becomes higher. Representatives of such vinyl monomers have a structural formula of wherein R. is hydrogen or methyl and R is an alkyl of l to [8 carbon atoms. Examples of the vinyl monomers are alkyl esters of acrylic or methacrylic acid, glycidyl acrylate. glycidyl methacrylate, methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, allyl acrylate, allyl methacrylate, hydroxypropyl methacrylate, diethylaminoethyl methacrylate. allyloxyethyl acrylate, allyloxyethyl methacrylate, styrene, a-methyl styrene. vinyl toluene. vinyl pyridine. butadiene, isoprene, chloroprene. acrylonitrile. methacrylonitrile, etc. Preferable examples of the vinyl monomers are alkyl (C to C,,) esters of acrylic or methacrylic acid and styrene. These vinyl monomers can be used alone or in admixture with one another. When vinyl monomer, such as vinyl acetate, having a Q value of less than 0.1 is subjected to emulsion polymerization using the present emulsifier, the polymerization reaction of the vinyl monomers can not proceed effectively, since the radical produced from the monomer is so active to easily react with maleinized butadiene polymer used as an emulsifier.  
  It is possible in the invention to copolymerize the hydrophobic vinyl monomers having a Q value of at least 0.1 with lower than 10 wt.7r, based on the above vinyl monomer, of water-soluble or hydrophilic other vinyl monomers. The examples of the latter are, for example, acrylic acid, methacrylic acid, itaconic acid, acrylam ide, N-methyl acrylamide, N-ethylacrylamide, methacryl amide, dimethylaminoethyl methacrylate, N- methylol acrylamide, N-methylol methacrylamide, N- methylol acrylamide butyl ether, Z-hydroxyethyl acrylate, Z-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, Z-hydroxypropyl methacrylate, acrolein, etc.  
  In the invention the vinyl monomer is polymerized in an aqueous medium in the presence of the maleinized butadiene polymer emulsifier. Such emulsifier is used in such an amount that theoretical acid value relative to the total solids contained in the resultant vinly polymer emulsion will be in the range of 5 to 150. &#34;Theoretical acid value relative to the total solid is determined by the following equation:  
 wherein A is acid value of maleinized butadiene polymer used, B is total weight in grams of maleinized butadiene polymer and vinyl monomers charged to the polymerization system and C is weight in grams of maleinized butadiene polymer charged to the polymerization system. When the amount of emulsifier is too small to achieve the above theoretical acid value of less than 5, emulsion polymerization can not proceed effectively. When the amount is so large as to give the theoretical acid value of over [50, the coating film obtained from the resultant polymer emulsion will tend to exhibit poor water resistance. Preferable amount of maleinized butadiene polymer emulsifier used is such an amount that the theoretical acid value relative to the total solids in the resultant polymer emulsion will be in the range of 15 to [20,  
  The emulsion polymerization of the vinyl monomers can be conducted under the same conditions as in the conventional emulsion polymerization thereof. For example. emulsion polymerization can be conducted in an aqueous medium in the absence or presence of a radical initiator or under irradiation of radiations. The polymerization is carried out at a temperature higher than freezing point of water but lower than boiling point of water under the reaction conditions. Stirring is preferable for the polymerization reaction, but it is possible to carry out the polymerization reaction without stirring when vinyl monomer is emulsified in aqueous medium prior to the polymerization reaction. lnitiators to be used are, for example, organic or inorganic peroxides, sulfides. sulfines, sulfinic acids, sulfones, azo compounds. diazo compounds, nitroso compounds. persulfates. perchlorates. wateror oil-soluble Redox initiators. etc. Besides. there may be used actinic light. photosensitizer, electric radiation. y-rays. x-rays. ultrasonic waves. etc. singly or in combination with the above or- 5 ganic or inorganic initiators.  
  To the polymer emulsion obtained in accordance with the present invention can be added various additives in accordance with the use of the emulsion. For example. when the emulsion is used as a vehicle for paint, pigments. plasticizers, extenders. dispersants. coalesing agents. other water-soluble polymers. etc. can be added to the emulsion. Further the polymer emulsion is also useful as adhesives. resin treating com positions, etc.. and in such a case plasticizers. coalesing agents. extenders. other vinyl monomers and the like can be added thereto. as required.  
  When the polymer emulsion is used as a vehicle for paint. the resultant paint can be applied to various substrates by conventional coating methods. such as spray coating. brush coating. roll coating, etc. The coated film can be cured at room temperature or elevated temperatures.  
 Reference Example I 150 g of polybutadiene having a number average molecular weight of l90O and consisting of 72% pf cis 1.4- bond. 27% of trans 1.4-bond and i7! of l.2-vinyl-bond (hereinafter referred to as polybutadiene A), 20 g of maleic anhydride and 75 ml of xylene were placed into an autoclave and reacted in a nitrogen gas atmosphere by heating at l90 to 200C for 5 hours with vigorous stirring.  
  After reaction. the resulting product was thoroughly washed with water. 60 ml of butyl cellosolve was then added to the product and water was removed therefrom by an evaporator to obtain maleinized polybutadiene solution. The resultant maleinized polybutadiene had an acid value of 93 and the solution thereof had a concentration of 85.6 wt.%.  
 Reference Examples 2 to Predetermined amounts of polybutadiene A. maleic anhydride and xylene were reacted at a given temperature for a given period of time to produce maleinized polybutadiene in the same manner as in Reference Example l. The amounts of the compounds. reaction conditions and properties of the resulting products are shown in Table l.  
  Products of Reference Examples 2. 3. 5. 9 and lo in Table l were obtained in the following manner. In Ref erence Example 8. methyl isobutylketone was used in place of xylene. ln Reference Examples 2. 3 and 9:  
  After the reaction. methanol was added to the product and the mixture was left to stand for 2 days to produce half ester. To the product thoroughly washed with methanol was added butyl cellosolve and methanol was removed from the resulting mixture by an evaporator. In Reference Example 5:  
  After the reaction. an excess amount of diethylamine was added to the product and the mixture was dissolved in methanol. The solution was then added to acetone to cause precipitation and the precipitate was separated and taken out. Ethyl cellosolve was added to the separated product. Acetone and methanol were removed from the mixture by an evaporator. To determine the acid value of the product. a portion of the sample was taken out after reaction and added to methanol for precipitation. The product thus purified was used for the determination. ln Reference Example 10:  
  After the reaction. the product was precipitated in methanol and the supernatant liquid was removed. ml of butyl cellosolve was added to the precipitate and methanol was removed from the mixture by an evaporator.  
 Reference Example 1 1 In the same manner as in Reference Example I, 150 g of polybutadiene A. 15 g of maleic anhydride and 75 ml of xylene were reacted at 175 to lC for 4 hours and then cooled. The product was thoroughly washed with water and residual water was removed by an evaporator. The resulting maleinized butadiene polymer had an acid value of 89.6 and was free from water.  
 Reference Example l2 in the same manner as in Reference Example I. g of polybutadiene A. 30 g of maleic anhydride and 50 ml of xylene were reacted at 170 to 190C for 4 hours and then cooled. The resulting product was washed with water and then with methanol. A small amount of water was further added to the product. this being followed by removal of methanol by an evaporator. The maleinized butadiene polymer obtained had an acid value of 140. This mixture contained 15.3 wt.% of water.  
 Table l Reference Example Nos. 2 3 4 5 6 7 8 9 l0 Pol hutadiene A (3) I50 l5() l5(] I50 I00 50 50 200 Starting Ma cic anhydride (g) 30 45 I2 30 30 30 5() 15 60 compounds Xylene (ml) 75 75 75 75 75 5O 50* 25 [U0 Heating I7()- 180- lRO- I73- l7()- l7()- l 75- Hit)- temperature (C) 185 I90 I90 I86 185 I85 180 I85 I85 Reaction Heating time (hr) 5 4 5 5 4 4 5 5 4.. conditions Methyl cellosolve (ml) 50 Solvent used u y cellosolve (ml) 50 fill 60 6U 4U 4U 2O 8O Acid value 76 lie 49 76 I ll I44 3lll I I5 l2l Properties Concentration (wt. &#39;r&#39;) 76.3 76.4 83.5 75.&#34; Ken 83.5 61.0 82.0 7h.&#34;  
 A methyl isohul \lkelune used in place of Xylene Reference Examples l3 to In the same manner as in Reference Example l. maleinized butadiene polymer was prepared. The amounts of starting compounds. reaction conditions and properties of the reaction product are given in Table 2.  
  ln Reference Example l4 in Table 2. the treatment after the reaction was conducted as follows. After cooling. 50 ml of glycerine was added to the product and the mixture was left to stand overnight to produce half ester. The resulting product was washed with methanol and butyl cellosolve was then added to the washed product. this being followed by removal of methanol by an evaporator.  
  The polybutadienes B and C listed in Table 2 were: Polybutadiene B; Polybutadiene having a number average molecular weight of 3000 to 4000 and consisting of 82.2% of cis l.4-bond. 15.47r of trans l.4-bond and 2.4% l.2-vinyl-bond.  
 Polybutadiene C: Polybutadiene having a number average molecular weight of i300 and consisting of 50% cis 1.4-bond. 4871 of trans l,4-bond and 27: of 1.2-vinylbond.  
 Reference Example I6 The maleinized butadiene polymer solution obtained in Reference Example 3 was washed with water and with methanol three times respectively. The washed solution was then left to stand in water for 3 days to completely release water-soluble components into water and the water was discarded. The resulting maleinized butadiene polymer is a mixture of 6.10 wt.% of water and 39.0 wt.% of maleinized polybutadiene (solid).  
 Reference Example 17 about 50 wt.7z ofmethanol and about 50 WLQP ofmaleinized polybutadiene (solid).  
 Reference Example 18 50g of polybutadiene A. 25 g of maleic acid and 25 ml of xylene were pleaced into an autoclave. which was then sealed. in the same manner as in Reference Example l, the mixture was heated at l90 to 225C for 5 hours under vigorous stirring for reaction. To the product thoroughly washed with water and methanol was added ml of butyl cellosolve. An evaporator was used to remove water and methanol. The resulting substance was precipitated in water again and thoroughly washed and left to stand in water for l day. Water was removed to obtain a mixture of maleinized butadiene polymer and water. The maleinized butadiene polymer was a mixture of 54.7 wt.7z of water and 45.3 wt.7r of maleinized polybutadiene (solid) and had an acid value of [20.  
 Reference Example [9 250 g of polybutadiene D (having a number average molecular weight of [420, with terminal carboxyl group having an acid value of 66.3 and consisting 10.2% of trans L l-bond and 89.8% of l.2-vinyl bond). g of maleic anhydride. ml of methyl isobutylketone and 150 ml of xylene were placed in an autoclave and reacted in a nitrogen gas atmosphere by heating at l to 190C for 4 hours with vigorous stirring. After the reaction, the resulting product was washed with water and then with methanol. ml of butyl cellosolve was added to the washed product, this being fol lowed by removel of methanol by an evaporator to obtain maleinized butadiene polymer solution. The maleinized butadiene polymer had an acid value of 89 and concentration of 77.4 wt.7r.  
 Reference Examples 20 to 23 In the same manner as in Reference Example l9, maleinized butadiene polymer prepared. The amounts of the starting compounds, reaction conditions and properties of the products are given in Table 3.  
 Table 3 Reference Example Nos. 2| 22 23 Polybutadicnc D (g) 250 Polybutadicnc E (g) 50 Polybutadicnc F (g) 125 Starting Polybutadicnc G (g) 300 compounds Malcic anhydridc (g) 75 50 50 l80 Xylene (ml) I80 80 200 Methyl isobutyl- 70 50 50 I50 kctonc (ml) Heating Temperature (Tl l90-200 l75-l 85 175-[85 IRS-I95 Reaction Heating time (hrs) 5 4 4 4.5 conditions Solvent used (butyl ccllosolvc. ml) [00 40 50 I20 Acid value l5l 283 l62 I90 Properties Concentration (wt. )l l 8] 59 92 B3 Polybutadiene E. F and G in Table 3 were: Polybutadiene E: Poly-butadiene having a number average molecular weight of l l50 and consisting of 8.7% of trans [.4- bond and 9l.37r of l.2-vinyl bond. Polybutadiene F: Polybutadiene having a number average molecular weight of 500 to 1000 with phenyl end group and consisting of I07: of cis l.4-bond. 457: of trans l.4-bond and 45% of 1.2-vinyl bond.  
 Polyhutadiene G: Polybutadiene having a number average molecular weight of l l00 and consisting of 89.2% of LIZ-vinyl bond and l0.87r of trans 1,4-bond.  
 Reference Example 24 200 g of polybutadiene H (having a number average molecular weight of 4040 and consisting of 8% of cis 1.4-bond and 9271 of 1.2-vinyl bond), 80 g of maleic anhydride. 100 ml of methyl isobutylketone and 150 ml of xylene were placed in an autoclave and reacted in a nitrogen gas atomosphere by heating at l85 to 195C for 5 hours with vigorous stirring. After the reaction, the product was divided into two equal portions. One portion was thoroughly washed with water and then precipitated in methanol. The other portion was directly precipitated in methanol. 40 ml of butyl cellosolve was added to both portions respectively, this being followed by removal of methanol with an evaporator to obtain maleinized polybutadiene solutions. The former was designated as Reference Example 24 l. with the latter as Reference Example 24-2. The product of Reference Example 24 1 had an acid value of I30 and solution concentration of 74 wt.7. while that of Reference Example 24 2 had an acid value of 86 and solution concentration of 80 wt.%.  
 Reference Example 25 100 g of styrene-butadiene copolymer (having a number average molecular weight of 2000 to 2400 and containing of butadiene polymer and 707r of 1.2- vinyl bond), l00 g of maleic anhydride. ml of methyl isobutylketone and I50 ml of xylene were placed in an autoclave and reacted in a nitrogen gas stream by heating at to l90C for 7 hours with vig orous stirring. After the reaction. the product was thoroughly washed with water and then precipitated in methanol. The supernatant liquid was removed and 40 ml of butyl cellosolve was added to the remaining substance. By removing methanol therefrom with an evaporator. a solution of maleinized butadiene copolymer was obtained. The copolymer had an acid value of I62 and concentration of 89.5 wt.%.  
 Reference Example 26 200 g of isobutylene-butadiene copolymer (having a number average molecular weight of 450 to 500, 3 to 4 unsaturated bonds per molecule and an iodine value of 150 to 200 g of maleic anhydride. 100 ml of methyl isobutylketone and l50 ml of xylene were placed in an autoclave and reacted in a nitrogen gas atomosphere by heating at l80to C for 7 hours with vigorous stirring. After the reaction. the product was thoroughly washed with water. 80 ml of butyl cellosolve was then added to the washed product. By removing water therefrom with an evaporator. a solution of maleinized butadiene copolymer was obtained. The copolymer had an acid value of I I6 and concentration of 87.2 wtf7r.  
 Reference Example 27 Partially cyclized polybutadiene having a molecular weight of i000 to I500 and represented by the formula H CH 78 l H CH CH was thoroughly washed with 20 wtT/r NaOH aqueous solution for a day in a nitrogen gas atomosphere and further washed with water and methanol. The polybutadiene was then dried.  
 no change in 3 hours water drop test.  
  The particle size measurement and water drop test were carried out in the following manner:  
 Particle size 200 g of this substance. 200 g of maleic anhydride. 200 ml of methyl isobutylketone and 300 ml of xylene Visible rays of a wave length of 430 p. and 700 a was were placed in an autoclave and reacted in a nitrogen irradiated to the polymer emulsion to be tested to meagas atomosphere by heating at 185 to 195C for 5 sure turbidity, and particle size was determined therehours with vigorous stirring. After the reaction. the from by Sakurada et al&#39;s method disclosed in Bull. Inst. product was thoroughly washed with water. 80 ml of 11) Chem Research (Kyoto Univ.) 42 (2 3) 145 (1964). butyl cellosolve was added to the Washed product. By v Water drop test L1I1U\ mg methanol therefrom with an evaporator. a solution of maleinized butadiene polymer was obtained. Polymer emulsion was applied to a glass plate and The polymer had an acid value of 193 and concentradried to produce a cured coating film. On the coating tion of 81.7 wtfil. film was placed water drop at room temperature to observe the changes of the film.  
 EXAMPLE 1 EXAMPLES 2 9 1n 71.5 g of butyl methacrylate were dissolved 0.5 of Polymer emulsions were prepared in the same mancobalt naphthenate and 2.0 g of lead naphthenate. 1n 30 net as in Example l except that polymerization was an autoclave the resultant solution was placed in comconducted under the conditions shown in Table 4 bebination with 40 g of maleinized polybutadiene ob- 10W. tained in Reference Example 1, 10 ml of 28% ammonia a polymer m i r ta n d 11 E amples 2 t0 9 water. 100 ml of water and 200 mg of ammonium perwas applied to a glass plate and cured at room temperasulfate. The air in the autoclave was replaced with niture, whereby transparent and hard coating film was trogen gas by repeating the procedures of re r obtained. The coatings obtained from the emulsions of duction and nitrogen gas replacement alternately for Examples v v 7. 8 and 9 r u jected t Wat r minutes. Thereafter the mixture was heated with drop test one day after coating. but no change was ob&#39; stirring at 75 to 85C for 2 hours, whereby polymer served on respective coatings in 3 hours test. Further emulsion having 478% solid content was obtained. The 30 the coatings obtained from the emulsions of Examples particle size of the polymer in the emulsion was 0.14 to 3 and 5 were subjected to the same test 2 days and 7 0.18 a and theoretical acid value of the product was days after coating respectively. no change was ob- 30.0. on the assumption that butyl methacrylate was served on the coatings in 3 hours test. completely polymerized.  
 . 7 The resultant polymer emulsion was applied to a EXAMPLES 10 To glass plate and dri at m m emp ra ur wh re y Polymer emulsions were prepared in the same mantransparent and hard coating was obtained. The coatnor as in Example 1 except that polymerization was ing displayed such excellent water resistance that after du ted nder the conditions shown in Table 5 bebeing cured at room temperature for a day it showed 4) low.  
 Table 4 Example Nos. 2 3 4 5 b 7 8 9 Malcinized hutadiene polymer used (in 1 0 2 3 4 19 20 24-1 Reference Example Maleinizcd polybutadienc (g) 30 30 30 30 30 30 28% ammonia water (ml) 7 l0 10 10 10 7 10 10 Water (ml) 100 100 I05 I00 I10 105 100 110 Ammonium persulfatc (mg) 200 200 100 200 200 -l U1 Potassium persullatc (mg) lU IOU materials used 0 11 -uZOl&#39;tlSlMlhUlXtU- nitrile (mg) 200 Butyl me\hacry1atc(g) 71.5 71.5 71.5 71.5 71.5 71.5 71.5 71.5 Cobalt naphthtltt. (g) 0.5 0.5 0.5 0.5 0.5 0.5 0.2 0.: Lead naphthate (g) 2 2 1 2 2 2 2 Temperature (C| 7(1- (10- 53- 80 70- 60- Pol \meri/ation 85 75 )0 811 7U 7U conditions Timc (hr) 2 2 2 .1 2 2 3 3 Solid titlrllenl 47.5 47.3 45.3 44.8 48.1 45.0 40.1 42.0 (wtfli 1 Properties Particle size 1 014- (1.118 0.28 0.14 052 023 00s 0 05 (1,16 0.10 0.34 0.20 0.40 0.27 008 Acid value 24.0 9.3 24.0 28.1 18.3 22.0 18.3 30.3  
 Table Example Nos. 1&#39;; 11 1;: 13 1; 15 1 n M,  
 llaleinized butadiene polymer used (in Reference Example Nos. 5 Fl 9 1?. 1 15 p; a x  
 Maleinized butadiene 3o 54 2o ,0 30 2c 50 P 50 0 =0 polymer (g) 2873 rnmni 8 10 5 1o 10 1 1? 1o 10 Amgunr f &#39;Jatez&#39; 100 100 10C 19C l &#39;JO 1&#39;1) 1W 1?) 10? 110 II&#34; materials user. Ammonium persulfate (&#39;53) loo Potassium pemulrafie (as) 100 100 100 100 1m 100 100 i n methacrllflte 71.5 111. see 1.= 80.? P0. &#34;19&#39;- -1.= 1 r a r (g) I 5 1 7- 1. 1.  
  Ter&#39;pe &#39;oture C) 70- l5- 5E- 55- 55- 5 m 55- 55. g Polymeri- 5 3O 55 5 5 5 5 75 &#34;5 zetion condition: Time (hr) 1 2 2 2 2 2 2 2 2 Solid content (&#34;h 5- 3 7- 5- 7&#39; &#39;T 5-5 M2 4 1.0 Mi ,=.C  
 Propertie: 1e re 0.16- O. Bf- OJ-S- 3.l&#39;L &#39;f&#39; O.1 QJ U- O. 71- 9. &#34;1- &#39;I 0.1 OJ E 0.50 0.13 O. 9.71 0. 0. 0. :F&#34;  
 Acid value -5 98.5 57.1 29.3 57.9 273 37.6 55.1 51m .0.  
  in Example 19 polymerization reaction was conducted by further adding 5 ml of butylcellosolve to the system.  
  From polymer emulsions of these Examples were obtained transparent and hard coatings respectively.  
 EXAMPLES 21 TO 23 Polymer emulsions were prepared in the same manner as in Example 1 except that the polymerization was conducted under the conditions shown in Table 6 be- Water resistance of the coatings obtained from the emulsionsof Examples l0. l6. l8 and 19 was extremely (15 excellent. Particularly. the coatings ofExamples l8 and 19 showed no change in 20 hours in water drop test conducted on the coating films one day after coating.  
 EXAMPLES 24 TO 26 Polymer emulsions were prepared in the same manner as in Example l except that the polymerization was conducted under the conditions shown in Table 7 below.  
 Table 7 Example Nosv 24 25 26 Maleinized butadiene polymer used (in Reference Ex. Nos.) 25 26 27 Time (hr) Solid content lwtfii 46.0 44.5 46,0 Particle size (a) 0.10-0.20 0.06-0.08 0.05-0.10  
 Properties Acid value 44.3 31.2 49.2  
  EXAMPLES 27 TO 35 25 ner as in Example I using various vinyl monomers shown in Table 8 below. The polymerization conditions Polymer emulsions were prepared in the same man are also shown in Table 8.  
 Table 8 Example Nos.  
 Maleinized butadiene polymer used (in Reference Ex. Nos.) 3 7 l0 ll 20 2| 23 23 23 Maleinized hutadiene 20 30 30 4O 30 25 200 7 2 30 polymer l g) 2854 ammonia 7 l0 l0 l0 l0 I0 66 24 ll) water (ml) Amount of materials used Water (ml) l00 Ill) NM) NM) I00 737 240 I ll) Ammonium 200 300 3000 500 $00 persullatc (mg) Potassium 5O l 00 l ()0 200 persulfale (mg) Acrylic acid (3) 0.3  
 Ethyl ucrylate (g) 27 Butyl acrylute (g) 2-ethylhexyl aerylate (g) [g] Methyl melhaerylate (g) 220 7.2  
 Vinyl Ethyl monomers &amp; methaerylate (g) 8.2 amounts Butyl methacrylate (g) 67.2  
 Laulyl melhacrylulc lg) 220 Acrylamide (g) 5 Aerylonitrile (g) 3 Styrene (g) 28 38.2 72 72 Vinyltoluene lg) 30 Table 8 Continued Example Nos.  
 Maleinized butadicnc polymer used (in Reference .Ex. Nos.) 3 7 H] II 20 21 23 23 23 lsoprene lg] 3 (ilycidyl methaerylate (9.)  
  Temperature (C) 50-56 65-70 75-85 50-70 6070 70-80 70-30 56-75 70-85 Polymeri zation conditions Time (hr) 2 2 l l 2 6 2 5 (min) Solid content (wt. kl 43.0 47.0 38.0 47.0 45.5 42.0 41.0 40.0 34.0  
 Properties Particle size 0.48- 0.l l- 0.30- 0.l8- 0.50 0.50- 0.60- 0.60-  
 Acid value 20.2 33.7 34.8 38.0 48.4 52.0 57.0 56.0  
 In Examples 33 and 34 pressure reducing operation EXAMPLES 3 To 41 was not conducted prior to the polymerization reaction and in Examples 29 and pressure reducing operation was shortened by 5 minutes. After the reaction excess Polymer emulsions were prepared in the same manammonia was removed by an evaporator in Examples ner as in Example I. using various neutralizing agents 29, 33 and 34, and in Example 35 excess ammonia and 30 shown in Table 9. The reaction conditions are also unreaeted isoprene were removed. shown in Table 9.  
 Table 9 Example Nos. I 36 37 38 39 40 41 Malcinized hutadiene polymer used (in Reference Ex. Nos.) 5 6 6 7 20 24-l Maleinizcd butadienc 30 30 40 30 30 30 polymer (gl Water (ml) 120 I00 I10 I00 I00 I20 Potassium persulfate (mg) v 100 I00 tut) I00 I00 l on Styrene (g) 40 43.6 40  
 Amount of Butyl acrylate (g) 32.4 28.,8 32.4 materials used Butyl methacrylatc (g) 62.7 7L5 7|.5  
 Trimethyl amine (30 wt. 7? aq. soln.) (ml) 10 l5 &#39;lriethyl amine (ml) 4,5 Neutraliz- Ethyl amine ing (70 W117: aq. soln) (ml) 6 agent NaOH (g1 2.5 KOH (g) 3.0  
  Temperature (T) -66 -75 60-70 75-85 -80 70-80 Polymerization conditions Time (hr) 2 2 2 2 2 2 Solid Content 37.4 47.9 46.0 48.5 44.0 43.0 [wt/d I Properties Particle size (n) 0.43- 0.38- 0.1 l- 0.20- 0.12-  
 AClLl value l9.8 29.3 35.9 27.l 36.4 3 l .0  
 EXAMPLES 42 TO 47 Polymer emulsions were prepared in the same manner as in Example I. using various radical initiators carried out at room temperature and in Example 47 in the glass vessel placed in ice water. The polymerization conditions are also shown in Table 10.  
 Table l Example Nos. 42 43 44 45 46 47 Maleinized butadiene polymer used (in Reference Ex. Nos.) 12 11/12 U I) l) 20 Maleinized butadicne 40 20/20 4 30 30 30 polymer (g) 28% ammonia water (ml) l 7 B 7 Water (ml) I00 100 I2 I00 I00 )00 Butyl cellosolve (ml) l0 Methyl eellosolve (ml) 20 Amount of Butyl methaerylate (g) 7| .5 62.7 7.2 7L5 71.5 71.5  
 materials used Potassium 100 persulfate (mg) FeCl 0. l6  
  hydrogen initiators peroxide (ml) 1.0  
 a.a&#39;-azohisisohutyl nitrile (mg) I00 200 &#39;y-rays (r/hr) 2.5Xl0 2.5Xl0  
  Temperature (T) 50-65 70-80 Room 70-80 -65 0 Polymerization conditions Temp.  
 Time (hr) 2 2 l0 2 2 4 Solid content (wt. &#39;71) 45.5 40.9 42.2 45.0 450 45.0  
 Properties Particle size (4.4.) 0.24- 0.20- 0.36- 0428- 0.23-  
 Acid value 450 4) ,7 50.7 221) 22.0 380 EXAMPLES 48 TO 50 shown in Table l0 below, provided that in Examples 44 and 47 polymerization was conducted in a stationary state in glass vessel after the starting mixture was thor- Polymer emulsions were prepared in the same manner as in Example 1, except that the polymerization was conducted under the conditions shown in Table l 1 beoughly stirred. In Example 44 the polymerization was low.  
 Table l 1 Example Nos. 48 49 5O Maleinized hutadiene polymer used (in Reference Ex. Nos.) l6 I7 18 Malcinized butadienc 50 polymer (g) 28% ammonia water (ml) l0 l0 10 Water (ml) HO Amount of Butyl eellosolvc (g) l0 materials used Butyl methaerylate (mg) 7L5 7|.5 62.7  
 Ammonium persulfate (g) 200 200 200 Cobalt naphthenate (g) 0.5 0.5  
 Lead naphthenute (g) 2.0 0  
 Polymeri- Temperature (C) 65-75 (10-70 60-70 zation conditions Time (hr) 2 2 2 Table l 1 Continued Example Nos. 48 4&#39;4 50 Maleinized hutadiene polymer used (in Reference Ex. Nos.) I6 I7 l8 Solid content (wtffi) 42.9 43.4 34.0  
 Properties Particle size (at 0. l8- 028- (M2- Acid value 28.6 29.3 3 l .7  
 Note: Whole amount of the product obtained in Reference Example l EXAMPLE 51 In an autoclave were placed 30 g of maleinized polybutadiene obtained in Reference Example 3. 100 ml of water. 7 ml of 28% ammonia water. 7l.5 g of butyl methacrylate. 0.2 g of cobalt naphthenate. 0.3 ml of 30 wt. 71 hydrogen peroxide solution and 0.08 g of ferrous chloride. The air in the autoclave was replaced with nitrogen gas and the mixture was stirred at C for 4 hours for polymerization. During the stirring the temperature of system was increased up to 37C. Solid concentration of the resultant polymer emulsion was 45.5% and particle size of the polymer was 0. l 2 to 0. l 6 a. The theoretical acid value relative to the total solids of the emulsion was 28.0.  
  The polymer emulsion thus obtained was applied to glass plate and dried at room temperature for one 7 was used.  
  To the polymer emulsions obtained in Examples 1 to 9. l8 to I). 21 to 26. 37, 40 and 45 to 49 was added wt. 7! of titanium white of rutile structure. based on the solid weight in the emulsion and the mixture was thoroughly stirred to produce paint.  
  The paint was applied to a glass plate and dried at room temperature. The gloss, hardness and water resistance of the coating film were measured by the following methods. with the results shown in Table 12 below. ln Table I2 the properties of the coating film obtained in the same manner as above from commercial aeryl polymer emulsion are also shown for comparative purpose.  
 Specular gloss: ASTM D523-6ZT. (10  
 week. The resultant coating film had a pencile hardness, l &#39;F on each coating film dried of F and showed no change in 3.5 hours water drop a predetermined pfliud tesL w shown in Table 12.  
  flit-l Each polymer emulsion obtained &#34;&#39;1 Examples 10 to resistance. on the wing mm mud for 50 was applied to glass plate and dried at room tempera predetermined period shown ature. Thus it was found that each polymer emulsion in g l ggt gr g azzl xt these Examples except in Examples 28. 3 l 32 and 38 stand at a relative humidity gave a transparent and hard coating film. The coatings ll i i was shown in terms of the time of Examples 28, 31. 32 and 38 were cured at an elemun fmgcncmkm r blister vated temperature less than l00C to give a transparent (m the willingand hard film.  
 Table 12 Ex. Gloss 1 day 2 days 3 days 7 days Nos. Hardness Water Hardness Water Hardness Water Hardness Water resistance resistance resistance resistance 1 63 4B 4 hrs. 30 min. HB 12 hrs. HB 20 hrs. F 24 hrs. 2 59 3B 5 hrs. 10 min. HB 10 hrs. HB 24 hrs. F 2 days 3 74 68 I hr. 50 min. 3B 4 hrs. 30 min. B 6 hrs. HB 9 hrs. 4 bl 2B 4 hrs. HB 10 hrs. HB 24 hrs. F 24 hrs. 5 73 3B 30 min. B 1 hr. 30 min. H8 2 hrs F 3 hrs. 30 min. 6 63 (1B l2 hrs. B 24 hrs. HB 4 days B 6 days 7 66 3B 24 hrs. 33 3B 2B X 75 63 20 hrs. 48 4B 2B 9 88 38 24 hrs. 28 2B B IR 28 24 hrs. B B B I) so 38 24 hrs. B B B 21 88 3B 24 hrs. 38 3B 2B 22 78 48 24 hrs. 38 3B 3B 23 73 3B 20 hrs. 38 3B 3B 24 an e B a 2s 2s 2B 26 73 B HB 37 72 38 I0 min. 28 I7 min. HB 35 min HB 2 hrs 40 79 4B 10 hrs. 48 4B 3B 45 73 38 24 hrs. 3B 3B 3B 46 69 33 24 hrs. 38 3B 3B 47 75 38 24 hrs. 38 3B 3B 4H 78 48 i2 min. B 41 min. HH 2 hrs. H8 3 hrs. 30 min. 49 72 6B 3 hrs. 28 7 hrs. 8 l5 hrs. HB 24 hrs. (our pari- SI 38 7 min. 38 7 min. 38 I4 min. 38 40 min.  
 dition product being used in an amount such that the theoretical acid number relative to the total solids contained in the resultant polymer solution is in the range of 5 to 150.  
  2. The method according to claim I, in which said addition product is added to the polymerization system in the range of from l5 to in terms oftheoretical acid value relative to the total solids contained in the resultant polymer emulsion.