JPH0577684B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for recovering a polymer from a polymer latex. More specifically, the present invention relates to a method for continuously recovering a copolymer latex containing a maleimide monomer component, which has few fine particles and has good powder properties, under specific conditions. <Prior Art> In recent years, for the purpose of improving the heat resistance of AS resins, ABS resins, etc., the development of resins in which maleimide monomers are introduced as copolymer components has been progressing. As one of the manufacturing methods of this resin, for example, JP-A-57-
167341, JP-A-58-206657, JP-A-59-135210,
As disclosed in JP-A-59-184243 and JP-A-60-4544, sulfate ester salts and sulfonates such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate are used as emulsifiers to stabilize emulsion polymerization. Emulsion polymerization methods are known. In addition, as a method for recovering the polymer from the polymer latex obtained by the emulsion polymerization method, there is a method in which the latex is coagulated using a metal salt coagulant such as magnesium sulfate or calcium chloride, and the polymer is separated and recovered. It has been adopted. <Problems to be Solved by the Present Invention> However, when coagulating a polymer latex obtained by using the above-mentioned sulfuric acid ester salt or sulfonic acid salt as an emulsifying agent with a metal salt, it is necessary to continuously coagulate it especially for the purpose of increasing productivity. When treated, coagulated particles of the polymer become very small due to poor coagulation properties.
As a result, the following problems arise in the process of recovering the polymer. In other words, if very small coagulated particles are generated in the polymer latex coagulation process, the filter equipment is likely to be clogged in the next polymer separation process, and the separated wet cake has a high moisture content, which reduces drying efficiency. Furthermore, since the powder after drying has many fine particles, there are problems of poor productivity and workability, such as a decrease in yield due to scattering and difficulty in handling. <Means for Solving the Problems> The present invention solves the above-mentioned problems and provides a method for continuously recovering a polymer having very little fine powder and good powder properties from a polymer latex. In order to achieve this objective, the present inventors conducted extensive studies on the coagulation conditions for polymer latex, and found that the objective could be achieved by coagulating under specific conditions, leading to the present invention. Ivy. 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. 97 to 40 parts by weight of one or more monomers selected from ester monomers and 0 to 50 parts by weight of a monomer copolymerizable with these monomers are added to a sulfuric acid ester salt and /or Copolymer latex (A) obtained by emulsion polymerization using a sulfonate as an emulsifier
Selected from 10 to 100 parts by weight (solid content equivalent) and 10 to 90 parts by weight of a rubbery polymer, an aromatic vinyl monomer, an unsaturated nitrile monomer, and an unsaturated carboxylic acid and its ester monomer. Graft copolymer latex (B) 0 to 90 parts by weight of one or more monomers and 0 to 50 parts by weight of a monomer copolymerizable with these monomers. In a method for continuously recovering a polymer from a polymer latex consisting of parts by weight (in terms of solid content), the solid content concentration of the polymer latex is adjusted to 5 to 30% by weight, and this is added to divalent and/or trivalent polymer latex. In the presence of a water-soluble metal salt coagulant, the average temperature is 25°C lower than the glass transition temperature (Tg) of the copolymer in the copolymer latex (A) (Tg - 25°C) or higher (but 120°C or higher). The present invention provides a method for continuously recovering a polymer having few fine particles and good powder properties from a polymer latex, which is characterized in that the treatment is carried out at a residence time of 0.1 to 100 minutes. The method of the present invention will be explained in detail below. Γ Copolymer latex (A) Copolymer latex used in the present invention
(A) is obtained by emulsion polymerizing the above monomer using the above emulsifier in the presence or absence of a rubbery polymer. Here, the maleimide monomers include maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-laurylmaleimide, N-cyclohexyl Maleimide, N-glycidylmaleimide, N-phenylmaleimide, N-2,3 or 4-methylphenylmaleimide, N-2,3 or 4-ethylphenylmaleimide, N-2,3
or 4-butylphenylmaleimide, N-2,
6-dimethylphenylmaleimide, N-2,3 or 4-chlorophenylmaleimide, N-2,3
or 4-bromophenylmaleimide, N-2,
5-dichlorophenylmaleimide, N-3,4-
Dichlorophenylmaleimide, N-2,5-dibromophenylmaleimide, N-3,4-dibromophenylmaleimide, N-2,4,6-trichlorophenylmaleimide, N-2,4,6-tribromo Phenylmaleimide, N-2,3 or 4-
Hydroxyphenylmaleimide, N-2,3 or 4-methoxyphenylmaleimide, N-2,3
or 4-carboxyphenylmaleimide, N-
4-Nitrophenylmaleimide, N-4-diphenylmaleimide, N-1-naphthylphenylmaleimide, N-4-cyanophenylmaleimide, N
-4-phenoxyphenylmaleimide, N-4-
Benzylphenylmaleimide, N-2-methyl-
Examples include 5-chlorophenylmaleimide and N-2-methoxy-5-chlorophenylmaleimide, and one or more types can be used. Among these, N-aryl-substituted maleimides are particularly preferred. In addition, aromatic vinyl monomers that can form copolymers with maleimide monomers include styrene, α-methylstyrene, α-chlorostyrene, pt-butylstyrene, and p-methylstyrene. , O-chlorostyrene, p-chlorostyrene, 2,5-dichlorostyrene, 3,4-dichlorostyrene, p-bromostyrene, O-bromostyrene, 2,5-dibromostyrene, 3,4-
Examples include dibromostyrene, and one or two
More than one species can be used. Among these, styrene or α-methylstyrene is usually preferred. Examples of unsaturated nitrile monomers include acrylonitrile, methacrylonitrile, maleonitrile,
Examples include fumaronitrile, and one or more types can be used. Among these, acrylonitrile is usually preferred. Examples of unsaturated carboxylic acids and their ester monomers include (meth)acrylic acid and its methyl,
(meth)acrylic acid ester monomers such as ethyl, propyl, butyl, lauryl, cyclohexyl, 2-hydroxyethyl, glycidyl and dimethylaminoethyl, and maleic anhydride,
Examples include itaconic anhydride, citraconic anhydride, hymic anhydride, and mono- and dialkyl esters thereof. One or more types of these can be used. Among these, methacrylic acid, methyl methacrylate, maleic anhydride, etc. are usually preferred. Furthermore, monomers that can be copolymerized with the above monomers include ethylene, propylene, butene-1, pentene-1,4-methylpentene-1, vinyl chloride, vinylidene chloride, butadiene, acrylamide, methacrylamide, acetic acid. vinyl, vinylpyrrolidone, vinylpyridine, vinylcarbazole,
Examples include vinyl ether, vinyl ketone, coumaron, indene, acenaphthylene, and 2-isopropenylnaphthalene. In addition, the copolymer latex (A) in the present invention also means a graft copolymer latex obtained by copolymerizing the above monomers in the presence of a rubbery polymer. . Examples of the rubbery polymer constituting the graft copolymer include polybutadiene, styrene-butadiene random or block copolymer, hydrogenated styrene-butadiene random or block copolymer,
Acrylonitrile-butadiene copolymer, neoprene rubber, chloroprene rubber, isobutylene rubber, natural rubber, ethylene-propylene rubber, ethylene-propylene-conjugated diene rubber, chlorinated polyethylene, chlorinated ethylene-propylene-conjugated diene rubber, acrylic rubber, ethylene-acetic acid Vinyl copolymer, ethylene-methyl (meth)acrylate,
Examples include (meth)acrylic acid ester copolymers such as ethyl, propyl, butyl, glycidyl or dimethylaminoethyl, ethylene-vinyl acetate-glycidyl methacrylate copolymers, and ethylene-methyl acrylate-glycidyl methacrylate copolymers. It will be done. Both crosslinked and non-crosslinked materials can be used, or a mixture of two or more of these can be used. These rubbery polymers are manufactured by emulsion polymerization, or by emulsifying a solution of the rubbery polymer in a solvent in an aqueous medium in the presence of an emulsifier, and then removing or removing the solvent. Those that do not are used. Further, the content of the rubbery polymer in the copolymer is generally preferably in the range of 5 to 70% by weight. When producing the copolymer latex (A), the amount of maleimide monomer is limited to a range of 3 to 60 parts by weight. If the amount of maleimide monomer is less than 3 parts by weight, the effect of improving the heat resistance of the copolymer is small;
If it exceeds 60 parts by weight, the processability of the copolymer will deteriorate. A particularly preferable range of the maleimide monomer is 5
~50 parts by weight. The emulsifiers used in emulsion polymerization are sulfate ester salts and/or sulfonate salts. Sulfate ester salts generally include alkali metal salts such as higher alcohol sulfates having 10 to 20 carbon atoms, higher alkyl ether sulfates, alkyl phenyl ether sulfates, sulfated fatty acid esters, sulfated fatty acids, sulfated olefins, and ammonium salts. Salt is an example. Of these,
Sodium or ammonium salts of lauryl sulfate and polyoxyethylene nonyl phenyl ether sulfate are preferably used. Examples of the sulfonic acid salt include alkali metal salts such as alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, alkyldiphenyl ether disulfonic acid, α-olefin sulfonic acid, and sulfosuccinic acid diester. Of these,
Sodium dodecylbenzenesulfonate is preferred. The appropriate amount of these emulsifiers to be added is generally in the range of 0.4 to 2 parts by weight per 100 parts by weight of the total copolymerization components. If the amount is less than 0.4 parts by weight, polymerization stability will be poor, while if it exceeds 2 parts by weight, coagulation properties will be poor when recovering the polymer from the polymer latex. Moreover, if the amount of emulsifier is large, the foaming of the wastewater will become intense when the polymer is recovered from the latex. A particularly preferred range of the amount of emulsifier is 0.5 to 1.4 parts by weight. Emulsion polymerization is generally carried out in an aqueous medium in the presence of an inorganic water-soluble radical generator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, or an organic water-soluble radical generator such as t-butyl hydroperoxide or cumene hydroperoxide. Performed at ~150°C. In this case, polymerization can also be carried out in the presence of an inorganic or organic reducing agent. Further, the weight ratio of copolymer component/water is preferably in the range of 1/0.8 to 2.
In addition, the pH of the polymerization system should be 8 or less in terms of polymerization stability.
In particular, it is desirable to set it to 7 or less. Γ Graft copolymer latex (B) The graft copolymer latex (B) used in the present invention consists of the above-mentioned components. Here, rubber-like polymers, aromatic vinyl monomers, unsaturated nitrile monomers, unsaturated carboxylic acids and their ester monomers, and monomers copolymerizable with these monomers are The same ones mentioned in the section on copolymer latexes above can be used. The type of emulsifier contained in the graft polymer latex is not particularly limited, but its content is preferably in the range of 0.5 to 2 parts by weight based on 100 parts by weight of the solid content of the graft copolymer. Recovery of Γ Polymer In the present invention, the above-mentioned copolymer latex
The polymer is recovered from a polymer latex consisting of (A) 10 to 100 parts by weight (in terms of solid content) and graft copolymer latex (B) 0 to 90 parts by weight (in terms of solid content). If the latex (A) is less than 10 parts by weight (the graft copolymer latex (B) is more than 90 parts by weight), a polymer with excellent heat resistance cannot be obtained. In addition, when recovering the polymer, the solid content concentration of the polymer latex is 5 to 30% by weight, preferably
It is necessary to adjust the content to 10-25% by weight. If this concentration is less than 5% by weight, productivity will be poor, while if it exceeds 30% by weight, there will be a tendency for coarse particles to be produced and a large amount of coagulated matter to adhere to the inside of the coagulation device. As a coagulant for the polymer latex, divalent and/or trivalent water-soluble metal salts are used. Examples of these metal salts include sulfates and hydrochlorides of magnesium, calcium, zinc, and aluminum, and one or more of them can be used. The amount of these metal salts added depends on the amount of emulsifier contained in the polymer latex, but is usually in the range of 1 to 10 parts by weight per 100 parts by weight of the solid content of the polymer latex. Note that these metal salt coagulants are generally added as an aqueous solution. In the presence of the above-mentioned water-soluble metal salt coagulant, the polymer latex is heated to a temperature (Tg) 25°C lower than the glass transition temperature (Tg) of the copolymer in the copolymer latex (A).
-25℃) or above (but above 120℃) with an average residence time of 0.1 to 100 minutes. Depending on these processing conditions (concentration, temperature, time), it is possible to recover a polymer containing few fine particles and having an appropriate particle size. The processing temperature is the glass transition temperature (Tg) of the copolymer.
Temperatures lower than 25℃ (＜Tg−
25) is unsuitable because it increases the amount of fine coagulated particles produced. On the other hand, if the treatment temperature is too high than the glass transition temperature (Tg) of the copolymer, the formation of coarse particles and the adhesion of the polymer to the inside of the treatment equipment will increase, which is undesirable. A particularly preferred treatment temperature ranges from 20°C lower than the glass transition temperature of the copolymer (A) to 30°C higher than the glass transition temperature ("Tg-20" to "Tg+").
The average residence time also depends on the processing temperature of the polymer latex, but if it is less than 0.1 minutes, the coagulated particles of the latex will be small, while if it is processed for more than 100 minutes, there will be no further effect. Productivity decreases.
A particularly preferred range of average residence time is 0.2 to 60 minutes. In addition, when coagulating polymer latex, treating it in the presence of a sparingly water-soluble inorganic or water-soluble polymeric suspension stabilizer can suppress the adhesion of coagulated substances to the inner walls of the processing equipment. is effective. Furthermore, if the treatment liquid or separated waste water foams, it is effective to add a silicone-based or polyalkylene glycol-based antifoaming agent. As the equipment for coagulating the polymer latex, for example, one or more stirring tanks, a tubular device, etc. are used. Polymer latex and coagulant are continuously fed to these processing equipment. The processing liquid is heated by directly blowing steam into the processing apparatus or by a jacket heating method.
Note that unreacted monomers remaining in the polymer during treatment can also be removed by distillation. In addition, when processing polymer latex,
If you want to recover powder with good properties at as low a temperature as possible within the temperature range specified in the present invention, add a polymerization terminator at a stage when the residual monomer remains at about 7% or less in the process of producing polymer latex. Alternatively, a solvent that is insoluble in water but has an affinity for the polymer (such as toluene, xylene, or ethylbenzene) may be added to the polymer latex to lower the softening temperature of the polymer. There is a way to handle it. In this case, residual monomers and solvents can be removed by steam stripping after coagulating the polymer, or in subsequent processing steps, for example, by using an extruder equipped with a devolatilization device. Furthermore, there is no restriction on the pressure during treatment. The slurry obtained by coagulating the polymer latex can be dehydrated and washed using a belt filter or centrifugal dehydrator. The dehydrated wet cake can be dried using a rotary dryer, flash dryer, fluidized fluid dryer, etc., and recovered as a powder. It can also be recovered as pellets using an extruder for dehydration and granulation. In addition, antioxidants, heat stabilizers, light stabilizers, lubricants, plasticizers, antistatic agents, inorganic and organic colorants, flame retardants, surface gloss improvers, Various additives can be added, such as quenching agents, inorganic and organic fillers. Depending on the type of additive, these additives can be added during the latex production process, polymer recovery process, or subsequent processing process.
Furthermore, various polymers can also be blended. The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Note that all parts and percentages shown in the examples are based on weight. Reference example 1 Copolymer latex (A) Reference example 1-1 70 parts of pure water, 0.02 part of potassium persulfate, and 0.1 part of sodium dodecylbenzenesulfonate were charged into a turbine-type reactor equipped with stirring blades, and the inside of the reactor was filled with nitrogen gas. After replacing the mixture with To this is added a solution consisting of 30 parts of N-phenylmaleimide, 15 parts of acrylonitrile, 55 parts of styrene and 0.3 parts of t-dodecylmercaptan, and a solution consisting of 0.2 parts of potassium persulfate, 0.7 parts of sodium dodecylbenzenesulfonate and 50 parts of pure water. was added continuously over 5 hours. Then 80℃
The temperature was raised to 2 hours and the polymerization rate was 97.8%, pH 2.7.
of latex was obtained. Reference Example 1-2 80 parts of pure water, 0.05 part of potassium persulfate, and sodium lauryl sulfate were added to the reactor used in Reference Example 1-1.
After charging 0.2 parts of N-phenylmaleimide, purging the inside of the reactor with nitrogen gas, and heating it with stirring, the internal temperature reached 50°C. The solution was then heated to 75°C. To this is added a solution each consisting of 9 parts of N-phenylmaleimide, 18 parts of acrylonitrile, 63 parts of α-methylstyrene, and 0.4 parts of t-dodecylmercaptan, as well as 0.2 parts of potassium persulfate and sodium lauryl sulfate.
A solution consisting of 1.2 parts and 40 parts of pure water was added continuously over 6 hours. After that, raise the temperature to 80℃ and
After holding for a period of time, a latex with a polymerization rate of 97.4% and a pH of 2.6 was obtained. Reference Example 1-3 90 parts of pure water, 0.01 part of potassium persulfate, and 0.1 part of sodium dodecylbenzenesulfonate were charged into the reactor used in Reference Example 1-1, and after purging the inside of the reactor with nitrogen gas, the mixture was stirred. was heated to 75°C.
To this was added a solution consisting of 40 parts of N-phenylmaleimide, 15 parts of acrylonitrile, 45 parts of styrene and 0.4 parts of t-dodecylmercaptan, and a solution consisting of 0.1 part of potassium persulfate, 1.2 parts of sodium dodecylbenzenesulfonate and 40 parts of pure water. The addition was continued over a period of 5 hours. Thereafter, the temperature was raised to 80°C and maintained for 2 hours, resulting in a latex with a polymerization rate of 98.5% and a pH of 2.6. Reference Example 1-4 The method of Reference Example 1-1 was repeated except that the amount of sodium dodecylbenzenesulfonate that was continuously added was changed to 2 parts. As a result, a latex with a polymerization rate of 98.3% and a pH of 2.7 was obtained. Reference Example 1-5 In the reactor used in Reference Example 1-1, a latex consisting of 20% acrylonitrile and 80% butadiene [solid content 45%, weight average particle diameter 0.24 μm, gel content 85%,
Emulsifier sodium dodecylbenzenesulfonate
1.7% (based on solids), PH6.2] in terms of solid content, 100 parts of pure water, 0.45 parts of sodium pyrophosphate, and 0.005 parts of ferrous sulfate were added, and the inside of the reactor was flushed with nitrogen gas. The mixture was replaced and heated to 70° C. with stirring. To this was added a solution consisting of 20 parts of N-phenylmaleimide, 20 parts of acrylonitrile, 60 parts of styrene and 0.4 parts of t-dodecylmercaptan;
- A solution consisting of 0.4 parts of butyl hydroperoxide, 1.1 parts of sodium dodecylbenzenesulfonate and 30 parts of pure water was continuously added over 6 hours. Thereafter, the temperature was raised to 80°C and maintained for 2 hours. As a result, a latex with a polymerization rate of 98.7% and a pH of 2.8 was obtained. Reference Example 1-6 Into the reactor used in Reference Example 1-1, 80 parts of pure water, 0.1 part of potassium persulfate, 0.1 part of sodium dodecylbenzenesulfonate, and ammonium polyoxyethylene nonyl phenyl ether sulfate were added.
After 0.1 part of the reactor was charged and the inside of the reactor was purged with nitrogen gas, it was heated to 70°C with stirring. To this, N-O-
A solution consisting of 25 parts of chlorophenylmaleimide, 75 parts of methyl methacrylate and 0.3 parts of terpinolene, along with 0.3 parts of potassium persulfate, 0.6 parts of sodium dodecylbenzenesulfonate, 0.6 parts of ammonium polyoxyethylene nonyl phenyl ether sulfate and 30 parts of pure water. A solution consisting of was continuously added over 7 hours. Thereafter, the temperature was raised to 80°C and maintained for 2 hours, resulting in a latex with a polymerization rate of 99.2% and a pH of 2.7. As a result of measuring the glass transition temperature of the copolymer obtained in Reference Example 1 using a differential scanning calorimeter, the following values were obtained. Copolymer Glass transition temperature (℃) Reference example 1-1 150 〃 1-2 146 〃 1-3 163 〃 1-4 149 〃 1-5 132 〃 1-6 143 Reference example 2 Graft copolymer latex (B ) Graft copolymer latexes each having the following components and characteristic values were used.

[Table] Example 1 Copolymer latex (A) produced in Reference Example 1-1
Pure water was added to adjust the solid content concentration to 15%. This was continuously charged into a stirring tank made of SUS316 equipped with a turbine-type stirring blade and heated to 135°C by blowing steam into the tank. The pressure inside the tank at this time is 2.3
Kg/cm ² (gauge pressure). Add a 20% calcium chloride aqueous solution to this to make the solid content of the copolymer latex.
While continuously adding 25 parts per 100 parts, solidification treatment was performed continuously at a treatment temperature of 135° C. and an average residence time of 30 minutes. The solidified slurry was cooled to 95°C through a jacketed pipe and then received in a receiving tank equipped with an agitator.
The polymer was separated from this slurry, washed with water, and dried. Example 2 The method of Example 1 was repeated except that the treatment temperature was 145° C. and the average residence time was 15 minutes. Example 3 Copolymer latex (A) produced in Reference Example 1-1
70 parts (in terms of solid content) and 30 parts (in terms of solid content) of the graft copolymer latex (B) shown in Reference Example 2-1 were mixed. To this, per 100 parts of solid content in the latex mixture, 0.3 part of trisnonylphenyl phosphite, 0.2 part of dilauryl-3,3'-thiodipropionate, triethylene glycol bis[3-t-butyl-5-methyl After adding an emulsion consisting of 0.2 parts of -4-hydroxyphenyl)propionate, 0.03 parts of sodium dodecylbenzenesulfonate, 0.1 parts of polyvinyl alcohol, and 5 parts of pure water, pure water was added to form an emulsion in the polymer mixed latex. The solid content concentration was adjusted to 20%. This was continuously charged into the stirring tank used in Example 1, and a stem was blown into the tank to heat it to 135°C. A 20% aqueous magnesium sulfate solution was continuously added thereto in an amount of 30 parts per 100 parts of the solid content of the polymer latex, and a coagulation treatment was continuously performed at an average residence time of 30 minutes. Thereafter, it was filtered, washed with water, and dried according to the method of Example 1. Example 4 Copolymer latex (A) produced in Reference Example 1-2
was used, the treatment temperature was 135℃, and the average residence time was
The method of Example 1 was repeated except for 40 minutes. Example 5 Copolymer latex (A) produced in Reference Example 1-3
60 parts (in terms of solid content) and 40 parts (in terms of solid content) of the graft copolymer latex (B) shown in Reference Example 2-1 were mixed. Hereinafter, the method of Example 3 was repeated except that the treatment temperature was 155°C. Example 6 Copolymer latex (A) produced in Reference Example 1-5
per 100 parts of solid content, 0.4 part of di(2,4-di-t-butylphenyl)pentaerythritol diphosphite, n-octadecyl-3(3',5'-di-
After adding an emulsion consisting of 0.2 part of t-butyl-4'-hydroxyphenyl) propionate, 0.1 part of dimyristyl-3,3'-thiodipropionate, 0.1 part of polyvinyl alcohol and 5 parts of pure water,
Add pure water to adjust the solids concentration of the copolymer latex.
Adjusted to 13%. Hereinafter, the method of Example 1 was repeated except that the treatment temperature was 125°C. Examples 7 and 8 Copolymer latex (A) produced in Reference Example 1-4
The method of Example 1 was repeated using 140° C. and 145° C., respectively. Example 9 Copolymer latex (A) produced in Reference Example 1-6
Pure water was added to adjust the solid content concentration to 15%. To this was added 5 parts of ethylbenzene per 100 parts of latex solids. This was continuously charged into the stirring tank used in Example 1 and heated to 125°C by blowing steam into the tank. Add a 15% aluminum sulfate aqueous solution to this to make the solid content of the copolymer latex.
Continuous solidification treatment was carried out with an average residence time of 25 minutes while continuously adding 20 parts per 100 parts. Thereafter, it was filtered, washed with water, and dried in the same manner as in Example 1. Example 10 Copolymer latex (A) produced in Reference Example 1-6
65 parts (in terms of solid content) and 35 parts (in terms of solid content) of the graft copolymer latex (B) shown in Reference Example 2-2 were mixed. Per 100 parts of solid content in the latex mixture, 0.2 parts of trisnonylphenyl phosphite and 0.2 parts of pentaerythritol-tetrakis-(β-lauryl-thiopropionate) are added.
part, 2-t-butyl-6-(3'-t-butyl-
An emulsion consisting of 0.2 parts of 5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 0.2 parts of sodium lauryl sulfate, and 5 parts of pure water was added, and then pure water was added to form a polymer latex mixture. The solid content concentration was adjusted to 17%. This was continuously charged into the stirring tank used in Example 1 and heated to 130°C by blowing steam into it. To this, a 15% aqueous solution consisting of a mixture of 50% calcium chloride and 50% magnesium sulfate was continuously added in an amount of 40 parts per 100 parts solid content of the polymer latex mixture, and a coagulation treatment was performed continuously at an average residence time of 30 minutes. .
Thereafter, it was filtered, washed with water, and dried in the same manner as in Example 1. Example 11 Copolymer latex (A) produced in Reference Example 1-1
Pure water was added to adjust the solid content concentration to 10%. This was heated to 95° C. while being continuously charged into a stirring tank equipped with a Foudler-type stirring blade. To this, 30 parts of a 20% aqueous calcium chloride solution was continuously added per 100 parts of solid content of the copolymer latex. This was continuously fed into the stirring tank used in Example 1, and a stem was blown into the tank to heat it to 140° C., where it was continuously treated with an average residence time of 30 minutes. Thereafter, the polymer was recovered in the same manner as in Example 1. Comparative Example 1 The method of Example 1 was repeated except that the treatment temperature was 110°C. Comparative Example 2 The method of Example 3 was repeated except that the treatment temperature was 100°C. Comparative Example 3 Copolymer latex (A) produced in Reference Example 1-2
Adjust the solid content concentration of 15% to 15%, charge it to the stirring tank used in Example 1, and blow steam into it to 135%.
heated to ℃. To this, add 20% calcium chloride aqueous solution at 25% per 100 parts solid content of copolymer latex.
After adding the sample for 2 seconds, immediately collect the sample from the sampling pipe into a container filled with cold water.
filtered, washed with water, and dried. Comparative Example 4 The method of Example 5 was repeated except that the solids concentration of the polymer latex mixture was 35%. However, during the process, the slurry extraction pipe became clogged with lumps, so the process was stopped. Further, there was also a large amount of polymer adhering to the inside of the stirring tank. Comparative Example 5 The method of Example 6 was repeated except that the treatment temperature was 105°C. Comparative Example 6 The method of Example 7 was repeated except that the treatment temperature was 95°C. Comparative Example 7 In Example 9, the method of Example 8 was repeated except that the treatment temperature was 115°C. Comparative Example 8 A polymer mixed latex prepared using the same recipe as in Example 10 was placed in the stirring tank used in Example 1, and heated to 130°C by blowing steam into it. This is an example
After adding 40 parts of a mixed aqueous solution of calcium chloride and magnesium sulfate prepared according to the same recipe as in 10 for 2 seconds per 100 parts of the solid content of the polymer latex mixture, a sample was immediately taken from the sampling pipe into a container filled with cold water. , filtered, washed with water, and dried. Example 12 A polymer mixed latex prepared using the same recipe as in Example 3 was placed in a stirring tank, and steam was blown into it.
Heated to 155°C. This latex was continuously fed into a SUS316 tube (with built-in static mixer) kept at 155°C with a jacket.
At the same time, 40 parts of a 15% aqueous calcium chloride solution per 100 parts of solid content of the polymer mixed latex was continuously added to the tube, and the treatment was carried out for an average residence time of 30 seconds. This treated slurry was cooled by adding cold water, filtered, washed with water, and dried. Comparative Example 9 The method of Example 11 was repeated except that the average residence time was 2 seconds. Comparative Example 10 The method of Example 11 was repeated except that the treatment temperature was 97°C. As described above, the physical properties of the coagulated polymer latexes obtained by processing in each of the Examples and Comparative Examples were measured. The results are shown in Table 1.

[Table] <Effects of the Invention> When latex is continuously coagulated under specific conditions according to the method of the present invention, a copolymer with a very small amount of fine particles and good powder properties is recovered. The effect is remarkable.

Claims (1)

[Claims] 1. 3 to 60 parts by weight of a maleimide monomer, an aromatic vinyl monomer, an unsaturated nitrile monomer, and an unsaturated carbon in the presence or absence of a rubbery polymer. 97 to 40 parts by weight of one or more monomers selected from acids and their ester monomers, and 0 to 50 parts by weight of monomers copolymerizable with these monomers.
10 to 100 parts by weight of a copolymer latex (A) obtained by emulsion polymerization using a sulfuric acid ester salt and/or a sulfonate as an emulsifier (in terms of solid content) and 10 to 90 parts by weight of a rubbery polymer. 90 to 10 parts by weight of one or more monomers selected from aromatic vinyl monomers, unsaturated nitrile monomers, unsaturated carboxylic acids and their ester monomers, and Graft copolymer latex (B) 0 consisting of the monomer and 0 to 50 parts by weight of a copolymerizable monomer
In a method for continuously recovering a polymer from a polymer latex consisting of ~90 parts by weight (in terms of solid content), the solid content concentration of the polymer latex is adjusted to 5 to 30% by weight, and this is divalent and/or trivalent. In the presence of a water-soluble metal salt coagulant having a high
℃ or higher) for an average residence time of 0.1 to 100 minutes. 2 The amount of the sulfuric ester salt and/or sulfonate added as an emulsifier when producing the copolymer latex (A) is 0.5 to 1.4 parts by weight based on 100 parts by weight of the total copolymerization components, and Divalent and/or trivalent coagulants for the combined latex
2. The method for continuous recovery of a polymer according to claim 1, wherein the amount of the water-soluble metal salt added is 1 to 10 parts by weight per 100 parts by weight of the solid content of the polymer latex.