JPS63101404A - Production of resin - Google Patents

Abstract

PURPOSE:To produce a resin with good productivity and workability, by copolymerizing a maleimide monomer with another monomer in the presence (absense) of a rubbery polymer in the presense of a specified emulsifier. CONSTITUTION:The emulsion polymerization of at most 20wt% of 3-60pts.wt. maleimide monomer (B), 97-40pts.wt. at least one monomer (C) selected from among an aromatic vinyl monomer, an unsaturated nitrile monomer and an unsaturated carboxylic acid (ester) monomer and 0-50pts.wt. monomer (D) copolymerizable therewith is started in the presence (absence) of a rubbery polymer (A) (e.g., polybutadiene) in an aqueous medium (E) of pH<=8, containing an emulsifier (F) comprising at most 50% of 0.4-1.4pts.wt., per 100pts.wt. total of components A-D, sulfuric ester salt and/or sulfonate. The polymerization is continued for 2-15hr at 50-150 deg.C and pH of the aqueous phase of the polymerization system kept at 8 or below while at least 80wt% of component B and at least 50wt% of component F are being continuously added to the polymerization system.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing a resin with improved productivity.

<Prior Art> In recent years, in order to improve the heat resistance of AS resins, ABS resins, etc., maleimide monomers have been introduced as copolymer components to develop phosphor resins.

As one of the manufacturing methods of this resin, for example, JP-A-57-1
67341, JP-A-58-206657, JP-A-5Q-
135210, JP-A-59-184243, JP-A-60
As disclosed in No. 4544, etc., emulsion is used to stabilize emulsification.

<The problem that the invention is trying to solve> However,
Generally, the amount of emulsifier used in the above emulsion superposition is 1100i of the total monomer mixture for stabilizing the polymerization.
! The amount of U is 91.5 to 4 M@ parts, and it is used in a relatively large amount. For this reason, the following problems occur particularly in the step of recovering the polymer from the polymer latex.

That is, when a large amount of emulsifier is added, productivity and workability are significantly inferior due to the following problems.

(1) In the salting out and dewatering processes, the wastewater foams violently, which requires the addition of multiple antifoaming agents. (2)
The latex has poor coagulability during salting out, and fine particles are likely to be produced, and as a result, clogging of the filtration device is likely to occur during the dehydration process of the salting out slurry. (3) The separated wet cake has a high moisture content and has poor drying efficiency. Furthermore (4
) After drying, the powder contains many fine particles, which reduces the yield due to scattering and makes it difficult to handle.

<Means for Solving the Problems> In order to solve the problems listed in items (1) to (4) above, the present inventors have sought to improve productivity and workability as well as to stabilize polymerization. As a result of extensive research into a method for producing a resin based on the formulation and conditions, the present invention was achieved.

That is, the present invention provides 3 to 60 parts by weight of a maleimide monomer, an aromatic vinyl monomer, an unsaturated nitrile monomer, and an unsaturated carboxylic acid in the presence or absence of a rubbery polymer. and its ester spinning wheel combination'n
A monomer mixture consisting of 97 to 40 parts by weight of two or more monomers and 0 to 50 parts by weight of a monomer copolymerizable with these monomers is emulsion polymerized. In the method of
As an emulsifier, a sulfuric acid ester salt and/or a sulfonic acid salt are used in the total amount of the monomer and the rubbery heavy substance. r
, provides a method for producing a resin, characterized in that 0.4 to 1.4 or more is continuously added to Dobe, and polymerization is carried out while maintaining the total pH of the polymerized water phase at 8 or less. .

The method of the present invention will be explained in detail below.

0 Monoedic acid maleimide monomers include maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, and N-lauryl. Maleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-2,3 or 4-methylphenylmaleimide, N-2,3 or 4-ethylphenylmaleimide, N-2,3 or 4-methylphenylmaleimide, N -2,6-dimethylphenylmaleimide, N-2,
3 or 4-chlorophenylmaleimide, N-2,3-
1 or 4-bromophenylmaleimide, N-2,5-dichlorophenylmaleimide), N-3,4-,:)chlorophenylmaleimide, N-2,s-dichlorophenylmaleimide, N- 3,4-dibromophenylmaleimide, N-2,4,6-) lJ dichlorohenylmaleimide, N-2,4-6-1J bromophenylmaleimide, N-2,3-! or 4-hydroxyphenylmaleimide, N-2゜3 or 4-methoxyphenylmaleimide, N-2,34-carboxyphenylmaleimide, N-4-nitrophenylmaleimide, N-4-diphenylmaleimide, N- 1-naphthylphenylmaleimide, N-4-cyanophenylmaleimide, N-4-phenoxyphenylmaleimide, N-4-benzylphenylmaleimide, N-2-methyl-5chlorophenylmaleimide, N-2-methoxy5-chlorophenylmaleimide Examples include n, and one or more types can be used. Among these, N-aryl[converted maleimide] is particularly preferred.

Examples of aromatic vinyl monomers include styrene, α-methylstyrene, α-chlorostyrene, pt-butylstyrene, p~methylstyrene, 0-chlorostyrene, p-1
Examples include O-rostyrene, 2,5-dichlorostyrene, 3,4-dichlorostyrene, P-7'lomostyrene, O-7'lomostyrene, 2,5-dipromostyrene, 3,4-dipromostyrene, etc. , one type or two or more types can be used.

Examples of unsaturated IJ monomers include acrylonitrile, metacyclonitrile, maleonitrile, and fumaronitrile, and one or more of them can be used. Among these, acrylonitrile is usually preferred.

Examples of unsaturated carboxylic acids and their ester monomers include (meth)acrylic acids such as (meth)acrylic acid and its methyl, ethyl, furoyl, butyl, lauryl, cyclohexyl, 2-hydroxyethyl, glycidyl, and dimethylaminoethyl; Examples include ester monomers and mono- and alkyl esters of maleic anhydride, itaconic anhydride, citraconic anhydride, hymic anhydride, and the like.

One or more types of these can be used. Among these, methacrylic acid, methyl methacrylate,
Maleic anhydride and the like are preferred. Furthermore, monomers capable of co-M association with the above monomers include ethylene, propylene, butene-1°pentene-1,4-
Methylpentene-1, vinyl chloride, vinylidene chloride, butadiene, acrylamide, methacrylamide, vinyl acetate, vinylpyrrolidone, vinyl ketone, vinyl chloride, vinyl ether, vinyl ketone, coumaron, indene, acenaphthylene, 2-impropenylnaphthalene, etc. Ru.

The addition ratio of the above polymer is 3 to 6 maleimide monomers.
0 parts by weight and one or more monomers selected from aromatic vinyl monomers, unsaturated nitrile monomers, unsaturated carboxylic acids and their ester monomers97-
The range is 40 parts by weight and 0 to 50 parts by weight of monomers that can be copolymerized with these monomers. If the amount of the maleimide monomer is less than 3M parts, the effect of improving the heat resistance of the resin will be small;
On the other hand, if it exceeds 60 parts by weight, processability deteriorates and is not practical. A particularly preferable amount of maleimide monomer is 5 to 5
All ON.

0 Rubbery Polymer Rubbery polymers include polybutadiene, styrene-butadiene random or block copolymer, hydrogenated styrene-butadiene random or block copolymer,
Acrylonitrile-butadiene copolymer, neoprene rubber, chloroprene rubber, inbutylene rubber, natural rubber,
Ethylene-propylene rubber, ethylene-propylene-conjugated diene rubber, chlorinated polyethylene, chlorinated ethylene-
Propylene-conjugated diene rubber, acrylic rubber, ethylene-vinyl acetate copolymer, ethylene-methyl (meth)acrylate, ethyl, propyl, butyl, glycidyl ti is a (meth)acrylic acid ester copolymer such as dimethylaminoethyl, ethylene -Vinyl acetate-glycidyl methacrylate copolymer, ethylene-methyl acrylate-glycidyl methacrylate copolymer, polyvinyl butyral, polyester elastomer, polyamide elastomer, and the like. Both crosslinked and uncrosslinked materials can be used, and mixtures of two or more types can also be used.

These rubbery M bodies are produced by the emulsification M e method, or by suspending a solution of the rubbery N bodies dissolved in a solvent in water in the presence of an emulsifier, and then removing or not removing the solvent. Furthermore, when a rubbery polymer is used, it is suitably used in an amount of 70 to 2 parts by weight based on 100M parts in total of the rubbery polymer and monomer.

. Emulsifier The emulsifier used in emulsion polymerization is a sulfate ester salt and/or a sulfonate salt.

Sulfuric ester salts generally include alkali metal salts and ammonium salts of higher alcohol sulfuric esters having 10 to 20 carbon atoms, higher alkyl ether sulfuric esters, alkylphenyl ether sulfuric esters, sulfated fatty acid esters, sulfated fatty acids, sulfated olefins, etc. Salt is an example.

Among these, sodium salt or ammonium salt of lauryl sulfate and polyoxyethylene nonylphenyl ether sulfate are preferably used. Also,
Sulfonate salts include alkylbenzenesulfonic acid,
Alkali metal salts such as alkylnaphthalene sulfonic acid, alkyldiphenyl ether disulfonic acid, α-olefin sulfonic acid, and sulfosuccinic acid diester are mentioned.
Ru. Among these, sodium dodecylbenzenesulfonate is usually preferably used.

The amount of these emulsifiers added is 0.4 to 1.4 parts by weight based on the total amount of monomers and rubbery polymers (ioo parts by weight). If the amount is less than 0.4 parts by weight, the stability is poor,
On the other hand, if it exceeds 1.4 parts by weight, many of the problems described above will occur, which is not preferable. A particularly preferred amount of the emulsifier added is 0.5 to 1.21 parts.

In addition, when emulsion polymerization is carried out in an alkaline system using an alkali metal salt of a higher fatty acid or an alkali metal salt of dehydroabietic acid, which are generally used as emulsifiers, a chemical reaction occurs due to hydrolysis of maleimide monomers. However, the use of these fatty acid salts is unsuitable due to poor polymerization stability.

0 Emulsion polymerization The emulsion polymerization of the present invention is generally carried out in an aqueous medium using an inorganic system such as potassium persulfate, ammonium persulfate, or hydrogen peroxide as a polymerization initiator. or using an organic radical generator such as t-butyl hydroperoxide or cumene hydroperoxide at 50 to 150°C for 2 to 15 hours.
Ru.

The polymerization can also be carried out in situ in the presence of an organic or inorganic reducing agent. In addition, the copolymer component/water'M volume ratio 1
The range of 10.8 to 2 is preferable.

A mixture of maleimide monomer and other monomers is charged all at once at the start of polymerization, and depending on the monomer charge ratio, a copolymer with a non-uniform composition may be formed. The presence of maleimide monomers instead of silica increases the polymerization rate very quickly.Especially when polymerization is carried out in industrial-scale polymerization equipment, the use of a relatively small amount of coloring agent stabilizes the polymerization. This can be resolved by adding a substance. The emulsifier and polymerization initiator are added as an aqueous solution, and the pH of the polymerization aqueous phase in emulsion polymerization must be maintained at 8 or less during polymerization. When the pH exceeds 8, polymerization stability deteriorates.

The preferred pH range of the aqueous phase is 2 to 7.0°. Also, emulsification! It is also possible to add interfacial tension modifiers such as pH modifiers and water-soluble metal salts in the process.Recovery of 0-0-1 polymerization Silatex obtained by emulsion polymerization, generally has a solid content of 5 to 30% by weight. %, a coagulant is added and coagulated, followed by dehydration, washing with water, separation, and drying to recover the co-N placed body. This operation can be carried out either batchwise or continuously.

As the coagulant, a divalent or trivalent water-soluble metal salt is used. Examples of these metal salts include magnesium,
Examples include sulfates and chlorides of calcium, zinc, and aluminum, and one or more of them can be used. The amount of these coagulants to be added is usually within the range of 1 to 100 parts of the solid content of the heavy latex.

The coagulation temperature of the latex is preferably a temperature corresponding to the glass transition temperature of the copolymer in order to reduce the amount of fine powder produced.

In addition, antioxidants, heat stabilizers, light stabilizers, lubricants, plasticizers, antistatic agents, inorganic and organic colorants, and difficult-to-understand additives may be added to the rt resin produced by the method of the present invention. Various additives such as repellents, surface gloss improvers, matting agents, inorganic and organic fillers, etc. can be added. Depending on the type of additive, these additives can be added in the latex manufacturing process, the Mzx body recovery process, or the subsequent processing process. Furthermore, it is also possible to completely distribute various polymers.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

It should be noted that the number of tomo portions and chi shown in the examples are all based on N meals.

70 parts of pure water, 0.02 part of potassium persulfate, and 0.1 part of dodecylbenzenesulfonic acid were charged into a reactor equipped with a turbine-type stirring blade and a plate baffle in groove 1001, and the inside of the reactor was flushed with nitrogen gas. After replacing, 140
The pH of the aqueous phase was 3.8 at the start of the 'itoM reaction, which was heated to 70°C with stirring at rpm. To this, a solution consisting of 30 parts of N-phenylmaleimide, 15 parts of acrylonitrile, 55 parts of styrene and 0.2 parts of t-dodecylmercaptan, as well as 0.2 parts of potassium persulfate and 0.4 parts of sodium dodecylsulfonate. An aqueous solution consisting of 50 parts of pure water and 50 parts of pure water was continuously added over 5 hours. after that,
The temperature was raised to 80°C and held for 2 hours, and the polymerization rate was 97.9cm, P
I got latex from H2 and 7.

Pure water was added to this latex to adjust the solid content concentration to 20%, and the mixture was charged into the 1001 reactor described above, purged with nitrogen, and then heated to 130° C. with stirring. Add 15% calcium chloride aqueous solution to 100 parts of latex solid content!
1140 parts were added over 10 minutes and then maintained at 130°C for 10 minutes. After cooling, the N combined material was centrifuged from the slurry, washed with water, and dried.

Example 2 80 parts of pure water, 0.05 part of potassium persulfate, and 0.2 part of sodium lauryl sulfate were charged into the reactor used in Example 1, and after replacing the inside of the reactor with nitrogen gas, the mixture was heated with stirring. When the temperature reached 70°C, a solution consisting of 1 part of N-phenylmaleimide, 2 parts of acrylonitrile, and 7 parts of α-methylstyrene was added, and then the temperature was raised to 75°C at the start of zero overlaying. The pH of the aqueous phase is 3.6, which is hot. Next, a solution consisting of 9 parts of N-phenylmaleimide, 18 parts of acrylonitrile, 63 parts of α-methylstyrene and 0.6 parts of t-dodecylmercaptan, 0.3 parts of potassium persulfate, and 1.0 parts of sodium lauryl sulfate were added. An aqueous solution consisting of 1 part and 40 parts of pure water was added continuously over 6 hours. Thereafter, the temperature was raised to 80°C and maintained for 2 hours to obtain a latex with an M content of 97.8% and a pH of 2.6.

Pure water was added to this latex to adjust the solid content concentration to 20%, and the above 1001! After charging the reactor and purging it with nitrogen, the temperature was raised to 125° C. while stirring. Add a 10% aqueous solution of magnesium sulfate and calcium chloride (magnesium sulfate/calcium chloride = 171) to 60 parts per 100 parts of solid content of e-latex. After cooling for 10 minutes, centrifuge the stacked body from the slurry. , washed with water and dried.

Example 3 70 parts of pure water, 0.02 parts of potassium persulfate, and 0.2 parts of sodium lauryl sulfate were charged into the reactor used in Example 1, and after purging the inside of the reactor with nitrogen gas, the reactor was heated to 80% with stirring.
Heated to 0°C. The pH at the start of heavy loading was 3.7.

40 parts of N-phenylmaleimide, 15 parts of acrylonitrile, 45 parts of styrene, and 0.
From a solution consisting of 0.01 part and 0.3 part of t-dodecyl mercaptan and 0.1 part of potassium persulfate, 0.5 part of sodium lauryl sulfate, 0.3 part of ammonium polyoxyethylene nonylphenyl ether sulfate and 50 parts of pure water. The aqueous solution was added continuously over 5 hours. After that, it was held at 80°C for 1 hour, and the polymerization rate was 98.7%.
A latex with a pH of 2.5 was obtained.

After replacing the solid content concentration by adding pure water to the latex, the latex was heated to 150° C. with stirring. On 15% aqueous calcium chloride solution per 100 parts solids of total latex
After adding 0 parts over 10 minutes, the mixture was held at 150°C for 15 minutes. After cooling, the M-placed body was centrifuged from the slurry, washed with water, and dried.

Example 4 50 parts of pure water, 0.02 part of potassium persulfate, and 0.1 part of sodium dodecylbenzenesulfonate were completely charged into the reactor used in Example 1, and the inside of the reactor was replaced with nitrogen gas.
It was heated to 75° C. while stirring. The pH of the aqueous phase at the start of polymerization was 3.9.

Cot”lAlCN-0-chlorophenylmaleimide 25
parts, 75 parts of methyl methacrylate and 0.0 parts of turbilsin.
A solution consisting of 4 parts and an aqueous solution consisting of 0.7 parts of sodium dodecylbenzenesulfonate, 0.5 parts of potassium persulfate and 50 parts of pure water were added continuously over a total of 7 hours.

After that, it was kept at 75℃ for 3 hours.As a result, the weighting rate was 99.
, 1%, P H2,5 latex was obtained.

Pure water was added to this latex to adjust the solid content concentration to 20%, and the mixture was charged into the above reactor and purged with nitrogen, and then heated to 130° C. with stirring.

To this was added 30 parts of a 20% magnesium sulfate aqueous solution based on 100 parts of the solid content of the latex over a period of 15 minutes, and then the mixture was held at 130° C. for 10 minutes. After cooling, the polymer was centrifuged from the slurry, washed with water, and dried.

Example 5 After charging 0.05 parts of aluminum and purging the reactor with nitrogen gas, the temperature was raised to 65° C. with stirring. The pH of the aqueous phase was 3.9, 7t, 0k, 1 part of N-phenylmaleimide, 1 part of acrylonitrile, 1.5i of styrene,
α-methylstyrene 1. After charging a solution consisting of 0.02 parts of s and 0.02 parts of t-dodecyl mercaptan,
The temperature was raised to ℃. Here, 19 parts of AN-phenylmaleimide, 19 parts of acrylonitrile, 2 s of styrene,
s parts, 28.5 parts of α-methylstyrene, and 0.4 parts of t-dodecylmercaptan, and an aqueous solution of 0.3 parts of potassium persulfate, 1 part of sodium lauryl sulfate, and 40 parts of pure water over 6 hours. Added continuously. Thereafter, it was held at 75°C for 3 hours. As a result, a latex with a weighting rate of 97.7% and a pH of 2.7 was obtained. below,
The method of Example 1 was repeated and the N bodies were collected.

Example 6 70 parts of pure water was charged into the reactor used in Example 1, and after purging the entire reactor with nitrogen gas, the reactor was heated to 70° C. with stirring. Ammonia persulfate was added to this. The pH of the aqueous phase is 4,
It was 2. This, 25 parts of N-phenylmaleimide,
20 parts of metacyclonitrile, 55 parts of styrene and t-
A mixed solution consisting of 0.1 part of dodecyl mercaptan, 0.3 part of ammonium persulfate, 0.5 part of sodium dodecylbenzenesulfonate, 0.5 part of ammonium polyoxyethylene nonylphenyl ether sulfate, and 40 parts of pure water. The aqueous solution was added continuously over 5 hours. Thereafter, the temperature was raised to 75°C and maintained for 3 hours. As a result, a latex with a weighting rate of 97.6% and a pH of 2.7 was obtained.

Thereafter, the method of Example 1 was repeated to recover the polymer.

Example 7 Into the reactor used in Example 1, 60 parts of pure water and polybutadiene latex (M amount of rubber average particle diameter 047 μm 1 gel content 76%, solid content 42%, emulsifier sodium lauryl sulfate 1.7%/rubber, PI After charging 30 parts (solid content equivalent) of (4,7), 0.02 parts of ferrous sulfate heptahydrate, 0.1 part of sodium pyrophosphate, and 0.2 parts of dextrose were added.PH of aqueous phase was adjusted to 4.5 with phosphoric acid. After purging the inside of the reactor with nitrogen gas, it was heated to 70°C with stirring. To this, 0.01 part of t-butyl hydroperoxide and 2 parts of pure water were added. After charging the solution, a solution consisting of 21 parts of LN-phenylmaleimide, 10 parts of acrylonitrile, 39 parts of styrene, and 0.2 parts of t-dodecylmercaptan, 0.2 parts of t-butyl hydroperoxide, and lauryl was added. An aqueous solution consisting of 0.5 parts of sodium sulfate and 25 parts of pure water was added continuously over a total of 4 hours.Then, the temperature was raised to 75°C and maintained for 2 hours.As a result, the polymerization rate was 98.5%, PH3, 6
of latex was obtained.

Pure water was added to this latex to adjust the solid content concentration to 25%, and the mixture was charged into the above-mentioned reactor, the atmosphere was replaced with nitrogen, and the temperature was raised to 130° C. while stirring.

To this, 30 parts of a 20% aqueous magnesium sulfate solution (f) per 100 parts of latex solid content was added over a period of 10 minutes, followed by holding at 130°C for 10 minutes. After cooling, the entire polymer was centrifuged from the slurry and washed with water. , dried.

Example 8 Into the reactor used in Example 1, 50 parts of pure water and polybutyl acrylate latex (rubber weight average particle size 0.21
μm, gel content 72%, solid content 40%, emulsifier sodium dodecylbenzenesulfonate 1.5%/rubber, P H5
, 2) After charging 30 parts (solid content equivalent), 0.05 part of sodium dodecylbenzenesulfonate, 1st sulfuric acid
0.001 parts iron, 0.1 part sodium pyrophosphate and 2 parts dextrose were added. P Hk of aqueous phase
It was adjusted to 5.0 with IJ acid. After purging the reactor with nitrogen, a solution consisting of 1.4 parts of N-phenylmaleimide, 1.4 parts of acrylonitrile, and 4.2 parts of styrene was added under stirring, and the temperature was raised to 75°C. The pH at the start of heavy loading is 3
．． It was 7. KN-phenylmaleimide 12.6
12.6 parts of acrylonitrile, 37.8 parts of styrene, 0.1 part of t-dodecylmercaptan, 0.2 part of Kikomene hydroperoxide, 0.5 part of sodium dodecylbenzenesulfonate, and pure water. An aqueous solution of 30 parts was added continuously over a period of 3 hours. Thereafter, it was held at 75°C for 2 hours. As a result, the polymerization rate was 9
A latex of 8.6% and pH 3.8 was obtained. Thereafter, the method of Example 7 was repeated except that the temperature was set at 125° C. in the coagulation treatment of the latex, and the heavy isomer was recovered.

Example 9 70 parts of pure water was charged into the reactor used in Example 1, the inside of the reactor was purged with nitrogen gas, and then heated to 70° C. with stirring. To this was added an aqueous solution consisting of 0.01 part of potassium persulfate, 0.01 part of sodium lauryl sulfate, and 2 parts of pure water. The PHfds of the aqueous phase is 1 and 6. This AKN-
20 parts of phenylmaleimide, 20 parts of acrylonitrile,
A mixture of 50 parts of styrene, 10 parts of methacrylic acid, and 0.2 parts of 1-dodecylmercaptan, and an aqueous solution of 0.2 parts of potassium persulfate, 0.8 parts of sodium dodecylbenzenesulfonate, and 40 parts of pure water were mixed into 5 parts of pure water. O was added continuously over a period of time, and then the temperature was raised to 80°C and maintained for 2 hours.As a result, a latex with a polymerization rate of 97.2% and a pH of 1.4 was obtained. Hereinafter, the method of Example 1 was repeated to collect the overlying bodies.

Comparative Example 1 The method of Example 1 was repeated except that the amount of sodium dodecylbenzenesulfonate that was continuously added during the weighting was 3 parts in total.

As a result, a latex with a polymerization rate of 98.0% and a pH of 2.6 was obtained.

Comparative Example 2 The method of Example 1 was repeated except that the amount of sodium dodecylbenzenesulfonate continuously added during weighting was changed to 0.1. As a result, about 4 hours after polymerization, the emulsification system became unstable and became creamy, so polymerization was stopped.

Comparative Example 3 In Example 1, the method of Example 1 was repeated except that sodium dodecylbenzenesulfonate (0.5 parts in total) was added all at once at the beginning of N addition. As a result, the emulsification system became unstable and turned into a cream state about 3 hours after the start of the N-meeting, so the N-meeting was discontinued.

Comparative Example 4 70 parts of pure water, 0.1 part of potassium persulfate, and 0.1 vA k of potassium oleate were added to the reactor used in Example 1, and the pH was adjusted to 13. After purging the inside of the reactor with nitrogen gas, the reactor was heated to 70° C. while stirring at 140 rpm. The pH at the start of polymerization was 12.2. Today,
A solution consisting of 30 parts of f'LN-phenylmaleimide, 15 parts of acrylonitrile, 55 parts of styrene and 0.2 parts of t-dodecylmercaptan, as well as 0.1 part of potassium persulfate, 2 parts of potassium oleate and 50 parts of pure water. An aqueous solution consisting of was continuously added. As a result, about 30 minutes after the start of the polymerization, the emulsion system became unstable and lumps were precipitated, so the polymerization was stopped.

Comparative Example 5 The method of Example 7 was repeated except that the amount of sodium lauryl sulfate that was continuously added was changed to 3 parts. As a result, we obtained latex with a M attachment rate of 8.7 and a pH of 3.5, 0 or more, Example 1~! and Comparative Examples 1 to 5
The results are summarized in Table 1.

<Effects of the Invention> The superpositioned body produced by the method of the present invention has remarkable effects such as low foaming of the salting-out wastewater, low water content of the dehydrated cake, and small amount of fine powder produced. Moreover, the stability under load is also good.

Claims (1)

[Claims] In the presence or absence of a rubbery polymer, 3 to 60 parts by weight of a maleimide monomer, an aromatic vinyl monomer, an unsaturated nitrile monomer, an unsaturated carboxylic acid and its ester monomer Emulsion polymerization of a monomer mixture consisting of 97 to 40 parts by weight of one or more monomers selected from the group consisting of 97 to 40 parts by weight of one or more monomers and 0 to 50 parts by weight of a monomer copolymerizable with these monomers. In the method of A method for producing a resin, which comprises continuously adding at least 80% by weight of a maleimide monomer and 50% by weight or more of an emulsifier, and polymerizing while maintaining the pH of the polymerized aqueous phase at 8 or less. .