KR810000396B1 - Mercaptan activation by acid in the copolymerization of acrylonitrile - Google Patents

Abstract

Acid-activated mercaptans are used as chain transfer agents in the copolymn. of acrylonitrile(I), giving high conversions to polymers with high nitrile content and good processability. Thus, 75 parts I and 25 parts Me acrylate were added to compn. contg. Na dioctyl sulfosuccinate 0.85, poly (vinylpyrrolidone) 0.30, water 205, nitrile rubber(added as latex) 9, and H3PO4 0.067 parts. The polymn. mixt. was heated to 54≰C, treated with 0.06 parts K2S2O8 and 1.2 parts pentaerythritol tetrakis(3-mercaptopropionate) and polymd. 3.5h, giving a polymer with av. mol. wt. 126,885 and Brabender torgue at 230≰ and 35 rpm 2/20m-g after 10 min

Description

Polymerization Reaction with Acid Activated Mercaptan

The present invention provides a method for acid activation of mercaptans used as molecular weight modifiers when copolymerizing acrylonitrile with other monomas, in particular using an acid-activated mercaptan chain transfer systym to provide a nitrile copolymer having an appropriate molecular weight. It relates to a production method for obtaining a high polymer material.

Until the present invention has been made, there is no known method for acid activation of mercaptans used as molecular weight regulators when copolymerizing nitrile monomas such as acrylonitrile. When mercaptans, which have conventionally been used as a slow cause of copolymerization due to a low conversion rate, are treated by the method of the present invention, a desired nitrile polymer compound can be promptly produced in high yield.

The high molecular compounds to be applied to the present invention include monomers which can be mainly copolymerized with olefinically unsaturated nitriles and copolymerized with them, and optionally those made of rubber components.

The polymer of the present invention may be added to monomas and other components by batching, continuous or intermittent operation by any one of known polymerization methods such as bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, and the like. The reaction can proceed. Among them, a method of emulsion polymerization or suspension polymerization in a water-soluble medium is preferable. The polymerization is preferably carried out in the absence of molecular oxygen at a temperature of 0 ° to 100 ° C in the presence of an emulsifier or suspending agent and a polymerization initiator which generates free radicals in an aqueous medium.

The present invention uses preformed diene rubbers which can form homopolymers in water-soluble emulsions, for example, mainly using unsaturated monomer nitriles such as acrylonitrile and copolymerizing with nitriles in small amounts. It is suitable for the preparation of polymers made by polymerization in the presence of conjugated dienemonomas.

Conjugated diene monomars used in the present invention include butadiene-1,3-isopurene, chlorofurene, bromoprene, cyanoprene, 2,3-dimethylbutadiene-1,3,2-ethylbutadiene-1, 3,2,3-diethylbutadiene-1,3 and the like. Among the above monomas, butadiene-1,3- and isoprene which are most easily available and have excellent polymerization tendency are preferable.

(여기에서 R은 수소, C_1-4알킬, 할로겐)으로 표시되는 α―, β―올레핀성 불포화 모노니트릴류를 의미한다.In addition, the olefinic unsaturated nitrile used in the present invention is a structural formula

(Where R is hydrogen, C _1-4 alkyl, halogen) means α-, β-olefinically unsaturated mononitriles.

Such compounds include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like. Of these, the most suitable olefinically unsaturated nitriles for the present invention include acrylonitrile and methacrylonitrile and mixtures of both.

Olefinic unsaturated nitriles and other monovinyl monomer components copolymerizable with conjugated dienes include olefinic unsaturated carboxylic acid esters, vinyl esters, vinyl ethers, α-olefins, and vinylaromatic monomas.

류의 구조를 갖는 화합물이 있다.The above-mentioned olefinically unsaturated carboxyl esters

There is a compound having a class of structures.

Wherein R ¹ is hydrogen, C _1-4 alkyl, or halogen and R ₃ is C _1-6 alkyl. Examples of such compounds include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, Hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, methyl alpha chloro acrylate, ethyl alpha chloro acrylate and the like. Among the above compounds, methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate are most suitable for the present invention.

(여기에서 R'과 R＂은 C_1-7의 알킬이다)과 같은 구조를 가지며 그 탄소수는 4내지 10이다. 구체적으로는 이소부틸렌, 2-메틸부텐-1,2-메틸펜텐-1,2-메틸헥센-1,2-메틸헵텐-1,2-메틸옥텐-1,2-에틸부텐-1,2-프로필부텐-1등이 있으며, 이중에서도 이소부틸렌이 가장 바람직하다.Α-olepins used in the present invention

(Where R 'and R' are C _1-7 alkyl) and have 4 to 10 carbon atoms. Specifically isobutylene, 2-methylbutene-1,2-methylpentene-1,2-methylhexene-1,2-methylheptene-1,2-methyloctene-1,2-ethylbutene-1,2 -Propyl butene-1 and the like, of which isobutylene is most preferred.

In addition, the vinyl ethers mentioned above include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, methyl isopropylphenyl ether, ethyl isopropenyl ether, and the like. Above all, methyl ether, ethyl vinyl ether, propyl vinyl ether and butyl vinyl ether are particularly preferable.

The vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl acetate is most preferred.

Moreover, as vinyl aromatic monomer, styrene, (alpha) -methylstyrene, vinyltoluene, vinyl xylene, etc. are especially preferable among these.

The polymer useful in the present invention is 100% by adding 10 to 40% of (B) selected from 60 to 90% of (A) and (1) to (5) in the presence of 0 to 40 parts of (C). It is manufactured by polymerizing a part.

으로 표시되는 적어도 한가지의 니트릴, (B)는 다음의 (1)내지 (5)까지의 화합물중에서 선택 : (1) R₁과 R₂가 전술한 바와 같은 구조식

의 에스테르 (2)R'과 R＂가 전술한 바와 같은 구조식

Where (A) is a structural formula as described above for R

At least one nitrile represented by (B) is selected from the following compounds (1) to (5): (1) R ₁ and R ₂ are as described above

Esters of formula (2) wherein R 'and R'

(3) Vinyl ether selected from methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether and butyl vinyl ether

(4) vinyl acetate

(5) styrene

의 니트릴 모노머 및 R₁과 R₂가 전술한 바와 같은

의 에스테르그룹중에서 선택된 코모노머로 이루어진 고무 중합체로서 이 고무중합체의 성분을 50내지 100%의 중합된 공액 디엔화합물 및 0내지 50%의 코모노머로 이루어진다.(C) is a comonomer consisting of a conjugated diene monomer selected from a buradiene and an isoprene group and optionally styrene, wherein R is a structural formula

Nitrile monomers and R ₁ and R ₂ are

A rubber polymer consisting of a comonomer selected from the ester groups of which consists of 50 to 100% of a polymerized conjugated diene compound and 0 to 50% of a comonomer.

In the polymerization reaction of the present invention, a polymer chain regulator and an acid are used. The chain control agent is added to the polymerization only after 1 to 10% by weight of the monomers have been converted to the polymer. Note: United States Patent No. 3,891,722

In the present invention, the terms "chain transfer agent", "polymer molecular weight modifier", "polymer chain modifier" and "regulator" all have the same meaning. Used. In practice, the chain transfer agent refers to a compound that exhibits a function of reducing the molecular weight of a polymer formed when it is added to the polymerization reaction of free radicals. The most commonly used chain transfer agents are mercaptans. The chain transfer agents used in the present invention include primary, secondary and tertiary alkyl mercaptans having 4 to 16 carbon atoms, and examples thereof include n-dodecyl mercaptan, t-dodecyl mercaptan, n-dodecylthiol acetate, and penta. Tetramercapto esters of erythritol and betamercapto propionic acid, limonene dimercaptan and other known compounds (US Pat. No. 3,891,722). The polymerization regulator is used in an amount of 0.01 to 3% by weight of the monoma to be polymerized.

Preferred polymerization regulators for the purposes of the present invention are organic mercapto compounds containing one or more mercapto groups per molecule, such as limonene dimercaptans and tetraesters of pentaerythritol and betamercapto propionic acid.

In the case of using low molecular weight monomercaptan, an unpleasant odor and taste remain, whereas a resin prepared using a polymercaptopolymerization regulator has little smell, and thus is particularly preferable. Resin used in food or beverage packaging must be odorless or tasteless.

Acids used in the present invention include both inorganic and organic acids. Useful inorganic acids include, but are not limited to, halogenated acids such as phosphoric acid, sulfuric acid, hydrochloric acid or bromic acid; Nitric acids and useful organic acids include carboxylic acids such as acetic acid, propionic acid, citric acid, 3-mercapto propionic acid; Ascorbic acid, phosphoric acid having at least one acidic hydrogen, and the like. Most suitable acids for the present invention include acetic acid, citric acid, phosphoric acid, 3-mercapto propionic acid and esters of phosphoric acid. Phosphoric acid and its ester derivatives and salts are most useful because they prevent the polymer and other reactive components from agglomerating as the polymer forms in the polymerization reactor.

The polymerization reaction of the present invention should essentially be carried out at pH 6.5 or below.

The invention is described in more detail in the following examples, where the content of components is expressed in parts by weight unless otherwise specified.

Example 1

A. The following is described for the purpose of comparing conventional resin production methods that do not belong to the scope of the present invention.

* The amount of each component means the amount per 100 parts of monomer (phm).

A mixture of 0.85phm sodium dioctyl sulfosuccinate (70% active) and 0.30phm polyvinyl pyrrolidone in 205phm water is placed in a stainless steel polymerization vessel. To this mixture was added butadiene: acrylonitrile (70:30) elastomer latex containing 9phm of elastomer, and the total water content of the mixture was 230phm. Be sure to To this is added 75phm acrylonitrile and 25phm methyl acrylate. This mixture (pH6.8) is stirred in a stream of nitrogen and the temperature of the mixture is heated to 54 ° C.

Here, 0.06phm potassium persulfate is added.

At this point, 1.2 phm of pentaerythritol tetra-3-mercaptopropionate is added and the addition is continued over the first 80 minutes of the polymerization. The prepolymerization time is about 3.5 hours. The reaction mixture is cooled down and the conversion is 75% by total solids analysis. A portion of the resulting latex is condensed in warm water (72-74 ° C.) containing alum. The coagulated resin is washed with water and dried in vacuo. The molecular weight of the resin is 335.784 (weight average). The 10 minute Brabender plasticoder torque (230 ° C., 35 rpm) is 5000 metagrams.

B. Resin belonging to the scope of the present invention is prepared by the following method.

The same procedure as in Example 1A was carried out, but 0.067phm of phosphoric acid was added before the acrylonitrile and methylethyl acrylate monomers were added. The pH of the polymerization starting mixture is 3.2. The conversion in this case is 92% of theory and the resulting resin has a molecular weight of 126,885 and a Brabender torgue of 230 ° C., 35 rpm and 10 minutes is 2120 metagrams. Therefore, this resin has a molecular weight that can be easily applied to the operations commonly used to handle thermoplastic materials, while the resins described in A above have a molecular weight that is too large for application.

C. Follow the same procedure as in B of this example, but add 0.1phm phosphoric acid instead of 0.067phm phosphoric acid.

The pH of the polymerization mixture is 3 or less. The conversion rate is 89% and the resulting resin has a molecular weight of 120,% 7 and Bravenda torque after 230 ° C., 35 rpm and 10 minutes is 1440 metagrams. The small amounts of prefloc formed in B and C of this embodiment are soft, brittle and easily removable from the stainless steel interior of the reactor, whereas the prefloc formed in A of this embodiment is hard, unwieldy and reactive. It is attached to the inside of the stainless steel of the house.

Example 2

Following the method of Example 1, 0.85phm of dioctyl sodium sulfosuccinate, 0.3phm of polyvinylpyrrolidone, 0.05phm of phosphate of ethylene diaminetetraacetic acid, 0.1phm of phosphoric acid and 230phm of water were Stirring in a steel polymerization vessel and bringing the temperature of the reaction solution to 40 ° C. An elastomer, potassium persulfate and monoma are added as described in Example 1 (pH 3) and the temperature is 54 ° C. Pentaerythritol tetra-3-mercapto propionate 1.2 phm) is added to the mixture over the first 30 minutes. After 3.25 hours of polymerization, the temperature of the mixture is raised to 57 ° C and the total polymerization time is 6.5 hours. The conversion is 79% of theory, the molecular weight of the separated resin is 126,675 and the Bravenda torque is 1460 metagrams. Small amounts of prefloc are soft and crumb and do not stick to the interior of the reactor or the stirrer.

Example 3

A. 0.85phm of dioctyl sodium sulfosuccinate, 0.3phm of polyvinyl pyrrolidone, 204phm of water, 0.08phm of ascorbic acid and 0.07phm of sodium dihydrogen phosphate monohydrate are placed in a stainless steel polymerization reactor. Add. The mixture is stirred under a stream of nitrogen and heated to a temperature of 40 ° C. At this time, a latex made of 70:30 butadiene: acrylonitrile elastomer of 10.3 phm (based on solids) is added to make the total water content of the mixed solution be 230 phm. Monomer and reaction initiator (0.06phm potassium persulfate) are added as in Example 1A.

The mixture (pH5.7) is brought to 54 ° C and 1.3 phm of chain transfer agent, pentaethistitol tetra-3-mercaptopropionate, is continuously added to the polymerization mixture over the initial 30 minutes. The total polymerization time is 3.5 hours. After removal of the latex, only 0.25% by weight of prefloc is obtained and the solid material is soft, brittle and easily separated from the stainless steel reactor. The conversion rate is 77% of theory. The resulting resin had a molecular weight of 126,176 and a Brabender torque of 230 ° C., 35 rpm, and 15 minutes was 1290 metagrams.

B. Perform the same procedure as in Example A, but do not include 0.08phm of ascorbic acid (pH6.6). The conversion is 84% of theory and the resulting resin has a molecular weight of 193,336 and the Bravenda torque after 230 ° C., 35 rpm and 15 minutes is 2860 metagrams. However, the resin is not manufactured by the acid activity method and has too high molecular weight and high brabender torque and thus is not included in the scope of the present invention.

Example 4

A. Gapac RE 0-610 emulsifier is a mixture of phosphate esters consisting of tanol in nonyl phenoxy poly (ethyleneoxy) which is acidic because it has been replaced by phosphoric acid. Dissolve 1.25phm of Gapark RE-610 in 205phm of water.

To this mixture is added 9phm latex (based on rubber solids) consisting of 70:30 butadiene: acrylonitrile elastomer. The latex contains a sufficient amount of water so that the total water content of the mixture is 230phm. The pH of the distillate was adjusted to 3.7 by adding rare water potassium hydroxide and the resulting mixture was added to the stainless steel polymerization vessel. Monoma (75phm of acrylonitrile and 25phm of methylacrylate) is added to the reactor and heated and stirred under a stream of nitrogen to bring the initial temperature to 57 ° C. Initiate the polymerization by adding 0.06phm potassium persulfate and 1.6phm of pentaerythritol tetra-3-mercapto propionate is continuously added to the reaction solution over 75 minutes. After reacting for 4 hours, the resulting latex is cooled and separated from the reactor. The conversion rate is 85%, the resulting resin has a molecular weight of 104,030 and Brabenda Torque is 870 metagrams.

B. Repeat operation A of this example, but adjust the pH of the Gapark RE-610 emulsifier-water-elastic mixture to 4.2 with dilute potassium hydroxide solution. The conversion is 80% of theory and the Bravenda Torque of the resulting resin is 1540 metagrams.

C. Repeat operation A of the present example, and adjust the pH of the Gapark RE-610 emulsifier-water-elastic mixture to 4.5 with dilute potassium hydroxide solution. The conversion was 85% of theory and the resulting resin had a molecular weight of 164,894 and Bravenda Torque at 230 ° C., 35 rpm and 15 minutes was 2280 metagrams. Therefore, simply increasing the pH of the polymerization mixture from 3.7 to 4.5 increases the molecular weight from 104,030 to 164,894 and the bravenda torque increases from 870 to 2280 metagrams.

D. Repeat the operation of Example 4A, but adjust the pH of the GaPark-water-elastomer mixture to 3.7 with rare water potassium hydroxide and do not use pentaerythritol tetra-3-mercaptopropionate. In this experiment, which is outside the scope of the present invention, it is necessary to add a small amount (0.1phm) of sodium metabisulfite and use 0.09phm of potassium persulfate to achieve 90.5% electrolysis rate. The bravenda torque of the isolated resin is 3470 metagrams after 230 ° C., 35 rpm and 15 minutes. The resin does not melt completely in Bravenda and has a molecular weight of 293,480.

E. Repeat the above operation D but change the pH to 4.5. The conversion rate is 92% and the resulting resin does not melt in Bravenda under 230 ° C. and 35 rpm conditions. The molecular weight of the resin is 371,092. It can be seen that mercaptan and low pH conditions are essential to properly control the molecular weight of the above-mentioned resins containing high concentrations of nitrile in D and E broth.

Example 5

This embodiment relates to a method of using citric acid with mercaptan to control the molecular weight of the resin to be produced.

A. 0.85phm of dioctylsodium sulfosuccinate, 0.5phm of polyvinyl pyrrolidone. A mixture of 210 phm of water, 9 phm of 70:30 butadiene: acrylonitrile rubber latex (containing sufficient water to have a total water content of 240 phm) and 0.035 phm of citric acid monohydrate is added to a stainless steel polymerization reactor. 75phm of acrylonitrile and 25phm of methyl acrylate are added thereto. 0.04 phm of citric acid monohydrate is added thereto, and the distillate (pH 4.2) is stirred under a nitrogen stream and heated to 57 ° C. 0.04 phm potassium persulfate is added and 1.6 phm of pentaerythritol tetra-3-mercapto propionate is added continuously over 16 minutes. The time required for the prepolymerization reaction at 57 ° C. was 3.75 hours. The conversion is 89% of theory and the resulting resin shows 860 metagrams of Bravenda torque after 230 ° C., 35 rpm, 15 minutes.

B. Similar to the method described in A of this example, but without the use of satric acid (pH 6.8) to cause polymerization. The conversion is 82% of theory and the resulting resin shows 1900 metagrams of Bravenda Torque.

Example 6

This example describes a method of using 3-mercaptopropionic acid as an activator for a mercaptan used for molecular weight control of a resin.

A. 0.85phm of dioctyl sodium sulfosuccinate, 0.3 polyvinyl pyrrolidone, 9phm (based on solids), 70:30 butadiene: acrylonitrile rubber and 240phm of water were added to a stainless-steel reactor, followed by 75phm Acrylonitrile and 25 phm of methyl acrylate are added. The mixture is stirred under a stream of nitrogen and heated to 57 ° C. and the polymerization reaction is initiated by adding 0.06phm potassium persulfate. After reacting for 20 minutes, 1.6 phm of 3-mercapto propionic acid and pentaerythritol tetra-3-mercapto propionate mixture having an acid value of 4.05 is continuously added to the polymerization mixture (pH 4.8) over 40 minutes. The total reaction time is 5 hours and the conversion is 78% of theory. The resulting resin exhibits 1670 metagrams of Bravenda torque after 230 ° C., 35 rpm and 15 minutes.

B. The operation A of this example was repeated but the acid value of the 3-mercapto propionic acid-mercaptan mixture used was 21.9.

(The pH of the polymerization mixture is 3.8). The conversion rate is 79% of theory, and the bravenda torque of the produced resin is 840 metagrams after 230 ° C., 35 rpm and 15 minutes.

Example 7

This example describes a method of using acetic acid as an activator of mercaptan used as a molecular weight regulator of a resin.

The method of Example 6A is repeated but a mixture of 0.00858 phm of acetic acid and 1.6 phm of pentaerythritol tetra-3-mercaptopropionate is mixed using acetic acid instead of 3-mercapto propionic acid. The pH of the polymerization mixture is 5.8. The conversion rate is 84% of theory and the bravenda torque of the produced resin is 1240 metagrams after 230 ° C., 35 rpm, and 15 minutes.

Example 8

A. A mixture of 200phm water, 1.0phm sodium dioctyl sulfosuccinate and 0.5phm lecithin (50% activity) is added into the polymerization reactor. To this mixture are added 75phm of acrylonitrile, 25phm of methyl acrylate and 1.0phm of pentaerythritol tetra-3-mercapto propionate.

Divorce (pH 6.8) is aerated with nitrogen and 0.1phm potassium persulfate is added to it. The polymerization reaction is carried out for 15.5 hours with shaking at 60 ° C. The conversion rate is 95%. The bravenda torque of the produced resin was 300 metagrams after 230 ° C., 30 rpm, and 15 minutes.

This resin is too large to handle well and falls outside the scope of the present invention.

B. Repeat operation A but use 0.0379 phm of 3-mercaptopropionic acid as the polymerization composition (pH4.5). The conversion is 93% of theory, and the resulting resin exhibits 2080 metagrams of Bravenda torque after 230 ° C., 35 rpm, and 15 minutes.

Example 9

A. Add 250 phm of water and 2 phm of Gapark RE-60 emulsifier into the stainless-steel polymerization reactor. The pH of the mixture is 3.1. To the divorce was added 8.24% by weight of acrylonitrile-styrene monomer mixture and 10% by weight of limonene dimercaptan (total 0.1 phm). The mixture is stirred, ventilated through a stream of nitrogen, and heated to 70 ° C. at which time 0.1 pHm of azobisisobutyronitrile is added to initiate the reaction.

The rest of monoma-mercaptan mixture is added continuously over 5 hours. This mixed solution consists of 67.5 phm of acrylonitrile, 24.83 phm of styrene and 0.9 phm of limonene dimercaptan. In addition to the imanoma-mercaptan, the reaction is energized by adding 0.025phm of azobisisobutyronitrile at 1.5 and 3.0 hours after the start of the reaction.

After adding the mono-mercaptan mixture, the polymerization mixture is further heated at 70 ° C for 30 minutes. The conversion rate is 85%.

The resulting resin has a molecular weight of 88.550 and Bravenda torque is 950 metagrams.

B. Repeat operation A of this example and adjust the pH of the GaPark RE-610-water mixture to 7 with dilute potassium hydroxide before adding any component. The conversion is 88% of theory and the molecular weight of the resulting resin is 139,500, the bravenda torque is 2050 metagrams.

Example 10

A. Repeat the procedure of Example 9A but use 1.0 phm limonenedimercaptan instead of 1.0 phm t-butyl mercaptan. The pH-3.0 of GaPark RE-610 mixed solution is. The conversion is 80% of theory, the resulting resin has a molecular weight of 110,000 and its Brabendatorque is 1680 metagrams.

B. Repeat Example A operation but adjust the pH of the GaPark RE-610-water mixture to 7 with dilute potassium hydroxide before adding other compositions. The conversion is 83% of theory, the molecular weight of the resulting resin is 234,100 and Brabenda Torque is 3560 metagrams.

Example 11

A. 205 phm of water and 1.25 phm. The pH of GaPark RE-610 mixture is adjusted to 5.2 by the addition of dilute potassium hydroxide solution. To the distillate in the polymerization reactor is added 9phm (solid basis) of 70:30 butadiene: acrylonitrile elastomer latex so that the total water content of the mixture is 230phm. 90% by weight of 75phm acrylonitrile-25phm methylacrylate mixture is added and the remaining 10% by weight of the monoma mixture is used as a solvent for mercaptan (1.2phm t-butyl mercaptan). Add 75 minutes after this begins. The polymerization reaction is started by adding 0.06phm potassium persulfate and stirring under nitrogen stream at 60 ° C. The total reaction time is 3.5 hours and the conversion is 95%. The resulting resin had a molecular weight of 118,000 and its Bravenda torque was 1750 metagrams.

B. Repeat piece A of this example, but neutralize GaPPAR RE-610-water mixture before adding other ingredients to adjust pH to 2.1. The conversion is 93%, the resulting resin has a molecular weight of 107.000 and its Bravenda torque is 1440 metagrams.

Example 12

A. A resin not falling within the scope of the invention is prepared by an aqueous suspension method with a pH of 7.0. 0.1 phm of hydroxyethyl cellulose and 300 phm of water mixture are added into the polymerization reactor. To this mixture is added 75phm of acrylonitrile, 2phm of styrene and 0.2phm of pentaerythritol tetra-3-mercaptopropionate. The mixture is heated to 60 ° C. with stirring under a stream of nitrogen, at which time 0.1 phm of Va 2052 (2,2 ′ azobis- (2,4-dimethylvaleronitrile) initiator is added. After 15 minutes, 23 phm of styrene 0.8 phm of pentaerythritol tetra-3-mercapto propionate mixture is continuously added over 3 hours, 0.05 hours of Vaso 52 initiator is added after 1.25 hours and 2.25 hours after the start of the reaction. After the completion of the mercaptan mixture, the reaction mixture is further stirred for 15 minutes at 60 ° C. The mixture is cooled to room temperature and the resulting resin is separated by filtration and washed with water The resin is dried under reduced pressure and at 50 ° C. for 48 hours. The conversion rate is 70% The bravenda torque of the dried resin is more than 4000 metagrams after 230 ° C., 35 rpm, and 15 minutes.

B. Repeat A of this example, but add enough phosphoric acid to the initial polymerization mixture of water and monoma to bring the pH to 5. Polymer conversion is 78%. This resin exhibits 1700 metagrams of Bravenda torque after 230 ° C., 35 rpm, and 15 minutes.

Claims (1)

By free radical-generating polymerization initiator in the aqueous medium in the substantial absence of molecular oxygen at about 0 to 100 ℃ (A) structural formula

Wherein R is hydrogen, a lower alkyl group having 1 to 4 carbon atoms, or halogen; 60 to 90% by weight of at least one nitrile based on the total weight of (A) and (B). (B) (i) structural formula

Wherein R ₁ is a lower alkyl group having 1 to 4 carbon atoms or a halogen, and R ₂ is an alkyl group having 1 to 6 carbon atoms, and (ii) a structural formula

(Where R ′ and R ″ are alkyl groups having 1 to 7 carbon atoms), (α) group consisting of methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, and butyl vinyl ether 10 to 40% by weight (based on the total weight of (A) and (B)) of at least 1 member selected from the group consisting of vinyl ether, (vinyl acetate) and (styrene) (C) conjugated diene monomer and styrene selected from the group of (C) butadiene and isoprene, structural formula

Nitrile monomer having the formula (wherein R is as described above)

(However, R ₁ and R ₂ are the same as described above) rubber-like polymer of the comonomer selected from the group of ester (however, this rubber-like polymer is 50 to 100% by weight polymerized conjugated diene and 0 to 50% by weight comonomer) In the method of polymerization in the presence of 0 to 40 parts by weight, the polymerization reaction is carried out at a pH of 6.5 or less in the presence of 0.01 to 3% by weight of mercaptan based on the total weight of the parts (A) and (B). The polymerization method characterized by the above-mentioned.