KR20140108869A - Method for manufacturing copolymer latex, and copolymer latex - Google Patents

Abstract

A method for manufacturing a copolymer latex comprises the steps of emulsion polymerization wherein 1,3-butadiene and monomer composition including another monomer which is capable of polymerizing the 1,3-butadiene are polymerized under unsaturated hydrocarbon with one unsaturated binding; and mixing oil compounds including unsaturated hydro carbon obtained by distilling the copolymer latex after polymerizing in previous steps of manufacturing copolymer latex in the current emulsion polymerization so that the rates of the monomer compound, unused unsaturated hydro carbon and 4-phenyl cyclohexane are less than equal to 600 ppm for the total weight of the oil compound.

Description

METHOD FOR MANUFACTURING COPOLYMER LATEX, AND COPOLYMER LATEX,

The present invention relates to a process for producing a copolymer latex and a copolymer latex obtained by the process.

The latex of copolymer based on butadiene copolymer (copolymer latex comprising 1,3-butadiene as a main component) is widely used as a binder in paper coating field, carpet back sizing, wood-based adhesive, battery electrode, .

In the production of the butadiene-based copolymer latex, hydrocarbons may be used in addition to monomers, emulsifiers, polymerization initiators, molecular weight regulators, and the like.

As a method for producing such a copolymer latex, for example, Patent Document 1 discloses a process for emulsion polymerization of an aliphatic conjugated diene monomer and other monomers copolymerizable therewith by adding a branched alkane having 5 to 10 carbon atoms Is disclosed.

Further, Patent Document 2 discloses a method of performing emulsion polymerization in the presence of cyclic unsaturated hydrocarbons having an unsaturated bond in a ring selected from cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene and 1-methylcyclohexene .

Patent Document 3 discloses a method for emulsion polymerization of an aliphatic conjugated diene monomer, an ethylenically unsaturated carboxylic acid monomer, and other monomers copolymerizable therewith, in the presence of a chain unsaturated hydrocarbon having one unsaturated bond.

Japanese Unexamined Patent Application Publication No. 5-112604 Japanese Patent No. 2961207 Japanese Patent No. 2879121

In order to industrialize the emulsion polymerization using the hydrocarbon as described above, it is necessary to examine a method of reducing the manufacturing cost.

These hydrocarbons are usually volatilized and removed from the copolymer latex together with a monomer or the like remaining unreacted as an oil-based mixture by a method such as steam distillation after completion of the emulsion polymerization.

Therefore, in order to reduce the manufacturing cost, it is considered that the removed hydrocarbon is recovered and reused for the next emulsion polymerization.

However, if the removed oil-based mixture is reused as it is, there is a problem that the productivity of the copolymer latex is decreased or the productivity is deteriorated due to pollution of the polymerization system.

It is an object of the present invention to provide a process for producing an unsaturated monomer having one unsaturated bond in the case of emulsion polymerization of 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene in the presence of an unsaturated hydrocarbon having one unsaturated bond The present invention also provides a method for producing a copolymer latex which can obtain a copolymer latex having a small amount of aggregates, even when an oily mixture containing a hydrocarbon is reused.

The method for producing the copolymer latex of the present invention is a method for producing a copolymer latex by copolymerizing a monomer composition comprising 1,3-butadiene and other monomer copolymerizable with 1,3-butadiene in the presence of an unsaturated hydrocarbon having one unsaturated bond A method for producing a copolymer latex to be polymerized comprising the steps of mixing an oleaginous mixture containing unsaturated hydrocarbons obtained by distilling copolymer latex after polymerization in the preparation of a prior copolymer latex in a total amount of monomer composition, unused unsaturated hydrocarbon and oily mixture Vinylcyclohexene in the emulsion polymerization system of this time so that the ratio of the 4-vinylcyclohexene to the 4-vinylcyclohexene is 600 ppm or less.

The method for producing the copolymer latex of the present invention is also characterized in that a monomer composition comprising 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene is added to a monomer composition containing an unsaturated hydrocarbon having one unsaturated bond Which is obtained by distilling a copolymer latex after polymerization in the production of the former copolymer latex, with a monomer mixture containing an unsaturated hydrocarbon containing an unsaturated hydrocarbon and an unmodified unsaturated hydrocarbon and an oily mixture Vinylcyclohexene derived from an oil-based mixture to the total amount is 600 ppm or less.

Further, it is preferable that the method for producing the copolymer latex of the present invention is further distilled by heating the oil-based mixture to a temperature at which the unsaturated hydrocarbons are evaporated.

Further, in the process for producing the copolymer latex of the present invention, it is preferable that the unsaturated hydrocarbon is cyclohexene.

In addition, the copolymer latex of the present invention is characterized in that it is produced by the method for producing the copolymer latex.

According to the method for producing a copolymer latex of the present invention, it is possible to reduce the production cost by reusing unsaturated hydrocarbons, and to produce a copolymer latex having a small amount of aggregates.

Further, by reusing the unsaturated hydrocarbon, the amount of the unsaturated hydrocarbon to be discarded can be greatly reduced, and the environmental load can be reduced.

In the method for producing the copolymer latex of the present invention, a monomer composition comprising 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene is emulsified in the presence of an unsaturated hydrocarbon having one unsaturated bond Polymerize.

The monomer composition comprises, for example, from 10 to 90% by weight of 1,3-butadiene.

On the other hand, 1,3-butadiene may contain unreacted 1,3-butadiene which is recovered by steam distillation described later.

Examples of other monomers copolymerizable with 1,3-butadiene include aromatic monomers such as an alkenyl aromatic monomer, a cyanized vinyl monomer, an unsaturated carboxylic acid monomer, an unsaturated carboxylic acid alkyl ester monomer, an unsaturated monomer containing a hydroxyalkyl group, an unsaturated carboxylic acid amide monomer, .

Other monomers copolymerizable with 1,3-butadiene are blended in the monomer composition in a proportion of, for example, 10 to 90% by weight.

Examples of the alkenyl aromatic monomer include styrene,? -Methylstyrene, methyl? -Methylstyrene, vinyltoluene and divinylbenzene.

Among these alkenyl aromatic monomers, styrene is preferable.

Examples of the cyanoized vinyl monomers include acrylonitrile, methacrylonitrile,? -Chloroacrylonitrile,? -Ethyl acrylonitrile, and the like.

Of these cyanide vinyl monomers, acrylonitrile and methacrylonitrile are preferable.

Examples of the unsaturated carboxylic acid monomer include monobasic acids such as acrylic acid, methacrylic acid and crotonic acid, and dibasic acids (or anhydrides thereof) such as maleic acid, fumaric acid and itaconic acid.

Examples of the unsaturated carboxylic acid alkyl ester monomers include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, Fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, dimethyl itaconate, monomethyl fumarate, and monoethyl fumarate.

Among these unsaturated carboxylic acid alkyl ester monomers, 2-ethylhexyl acrylate and methyl methacrylate are preferable.

As the unsaturated monomer containing a hydroxyalkyl group, for example,? -Hydroxyethyl acrylate,? -Hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl Hydroxyethyl methacrylate, di- (ethylene glycol) maleate, di- (ethylene glycol) itaconate, 2-hydroxyethyl maleate, bis (2- Ethyl) maleate, 2-hydroxyethyl methyl fumarate, and the like.

Of these unsaturated monomers containing a hydroxyalkyl group, preferably? -Hydroxyethyl acrylate.

Examples of the unsaturated carboxylic acid amide monomer include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide and N, N-dimethyl acrylamide.

Of these unsaturated carboxylic acid amide monomers, acrylamide and methacrylamide are preferable.

As other monomers copolymerizable with 1,3-butadiene, monomers used in ordinary emulsion polymerization such as ethylene, propylene, vinyl acetate, vinyl propionate, vinyl chloride, and vinylidene chloride may also be used.

These other monomers copolymerizable with 1,3-butadiene may be used singly (only one type), or two or more types may be used in combination.

Examples of unsaturated hydrocarbons having one unsaturated bond include cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene, 1-methylcyclohexene, 1-pentene, , 2,4,4-trimethyl-1-pentene, and 1-octene.

Of these unsaturated hydrocarbons, cyclohexene is preferable.

These unsaturated hydrocarbons may be used singly (only one type), or two or more types may be used in combination.

These unsaturated hydrocarbons can be recovered from the copolymer latex after completion of the polymerization in the production of the copolymer latex, and can be reused in the production after the next cycle.

In order to recover the unsaturated hydrocarbon after completion of the polymerization of the copolymer latex, the unsaturated hydrocarbon is recovered from the copolymer latex together with the remaining unreacted monomers by distillation or the like.

The distillation method of the copolymer latex is not particularly limited, and a known method can be used. Preferably, steam distillation is carried out at 50 ° C to 100 ° C.

Herein, an oil-based mixture (hereinafter referred to as an "oil-based mixture") which is removed from the copolymer latex by distillation includes unsaturated hydrocarbons and volatile monomers, as well as 4-vinylcyclohexene (hereinafter, abbreviated as 4VC ).

In order to blend the oil-based mixture with 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene at the time of emulsion polymerization, the monomer composition, unused unsaturated hydrocarbons (that is, unsaturated hydrocarbons ) And the ratio of 4VC to the total amount of the oily mixture is, for example, 600 ppm or less, preferably 500 ppm or less, more preferably 400 ppm or less.

In addition, the oily mixture may also contain a proportion of 4VC derived from the oily mixture to the total amount of monomer composition, unused unsaturated hydrocarbons (i.e., unsaturated hydrocarbons in the oily mixture), and the oily mixture is, for example, 500 ppm or less, and more preferably 400 ppm or less.

If 4VC exceeding 600 ppm is carried into the emulsion polymerization system, the amount of aggregation is increased and the yield of the copolymer latex is lowered. In addition, the particle diameter of the resulting copolymer tends to increase, and the reproducibility of polymerization deteriorates.

As the method for controlling the amount of 4VC introduced into the emulsion polymerization system in the polymerization for reusing the oily mixture, the amount of 4VC in the oily mixture is measured, and the amount of 4VC introduced into the emulsion polymerization system is calculated to determine whether it can be reused as it is Can be determined.

At this time, the amount of 4VC contained in 1,3-butadiene used in the polymerization (which may contain unreacted 1,3-butadiene recovered by steam distillation) is also measured, and the amount of 4VC introduced into the emulsion polymerization system The amount of 4VC is calculated and added to the amount of 4VC transferred into the emulsion polymerization system from the oil-based mixture.

On the other hand, as a method for reducing the 4VC introduced into the emulsion polymerization system, for example, the oil-based mixture is further distilled by heating to a temperature at which the unsaturated hydrocarbon is evaporated to obtain a distillate containing an unsaturated hydrocarbon (hereinafter referred to as "distillate" For example, a method in which an oily mixture and a distillate are used in combination, for example, a method in which a new unsaturated hydrocarbon is used in combination with an oily mixture and / or a distillate. As for the distillate, the amount of 4VC in the distillate is measured in the same manner as in the case of the oily mixture, and the amount of 4VC introduced into the polymerization system is calculated according to the amount of the distillate to judge whether or not it can be reused.

By reusing the oily mixture and / or the distillate, the waste amount of the oily mixture containing the unsaturated hydrocarbons can be greatly reduced.

As the emulsion polymerization method in the present invention, a known method can be applied. That is, the method of adding monomers and other components is not particularly limited. Any of known methods may be adopted for the method of adding the monomers. In emulsion polymerization, known emulsifiers, polymerization initiators, chain transfer agents, electrolytes, chelating agents and the like can be used.

As the emulsifying agent, there may be mentioned, for example, sulfuric acid ester salts of higher alcohols, alkylbenzenesulfonates, alkyldiphenyl ether dodecylsulfonates, aliphatic sulfonates, aliphatic carboxylates, dehydroabietates, formalin condensates of naphthalenesulfonic acid, And anionic surfactants such as sulfuric acid ester salts of active agents, such as nonionic surfactants such as alkylester type, alkylphenylether type and alkylether type of polyethylene glycol.

These emulsifiers may be used alone (one type) or two or more types may be used in combination.

Examples of the polymerization initiator include water-soluble polymerization initiators such as lithium persulfate, potassium persulfate, sodium persulfate, and ammonium persulfate, such as cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide, acetyl peroxide, diisopropylbenzene hydroperoxide (Oil-soluble) polymerization initiator such as triphenylmethane, tripropylene glycol, tripropylene glycol, tripropylene glycol, tripropylene glycol, tripropylene glycol, tripropylene glycol, tripropylene glycol,

Of these polymerization initiators, potassium persulfate, sodium persulfate, cumene hydroperoxide and t-butyl hydroperoxide are preferably used.

Examples of the chain transfer agent include xanthene compounds such as alkylmercaptan, dimethylxanthogen disulfide, diisopropylxanthogen disulfide such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram Monosulfide, and the like, phenolic compounds such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol, allyl compounds such as allyl alcohol, for example, dichloromethane, Halogenated hydrocarbon compounds such as methane and carbon tetrabromide, for example, vinyl ethers such as? -Benzyloxystyrene,? -Benzyloxyacrylonitrile and? -Benzyloxyacrylamide such as triphenylethane, Ethane, acrolein, methacrolein, thioglycolic acid, thiomalic acid, 2-ethylhexylthioglycolate, terpinolene, alpha -methylstyrene dimer, Can.

These chain transfer agents may be used alone (only one), or two or more types may be used in combination.

The particle diameter of the copolymer latex obtained by the production method of the copolymer latex of the present invention is not particularly limited, and the average particle diameter by photon correlation method is, for example, 50 to 300 nm. When the average particle diameter of the copolymer latex is less than 50 nm, the viscosity of the copolymer latex becomes high and handling becomes difficult, which is not preferable. If the average particle diameter of the copolymer latex is larger than 300 nm, the surface area of the copolymer latex becomes small and the adhesive strength is lowered. The particle diameter of the copolymer latex can be adjusted by suitably changing various kinds of emulsifiers used in the polymerization of the copolymer latex, the type and amount of the polymerization initiator used, the addition method, and the ratio of the polymerized water (polymerization water) used .

The gel content of the copolymer latex in the present invention is not particularly limited, but is, for example, 30 to 100% by weight. If the gel content is less than 30% by weight, the adhesive strength tends to be lowered, which is not preferable.

In the polymerization of the copolymer latex of the present invention, known additives such as an oxygen supplement, a chelating agent, a dispersant, an antifoaming agent, an antioxidant, an antiseptic, an antibacterial agent, a flame retardant and an ultraviolet absorber may be used as necessary. These additives are not particularly limited in kind and amount to be used, and may be suitably used in appropriate amounts.

Example

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples unless they depart from the gist thereof. On the other hand, in the examples, parts and percentages representing percentages are by weight unless otherwise specified. The evaluation of various physical properties in the examples was based on the following method.

On the other hand, in this example, 1,3-butadiene containing 80 ppm of 4VC was used as "1,3-butadiene", cyclohexene not containing 4V (less than 1 ppm) as "cyclohexene" Used.

4VC contained in "1,3-butadiene" was quantified based on gas chromatograph measurement.

≪ Measurement condition of gas chromatograph of " 1,3-butadiene "

Sample volume: 0.5 μL

Detector: FID

Injection temperature: 250 ° C

Detector temperature: 250 ° C

Column: length / inner diameter / film thickness = 50 m / 0.53 mm / 50 탆 (GS-ALUMINA 115-3552)

Carrier gas: He 6 mL / min

Split ratio: 1/50

Column temperature: After being kept at 45 占 폚 for 3 minutes, the temperature was raised to 195 占 폚 at 6 占 폚 / min and held at 195 占 폚 for 15 minutes.

≪ Evaluation method of various physical properties &

1. Method for measuring the amount of aggregate in copolymer latex

After the completion of the polymerization, 1 kg of the copolymer latex was sampled as a sample before steam distillation, and the mixture was filtered through a 300 mesh wire net made of stainless steel. After the coagulum remaining on the wire mesh was dried, the weight was measured, and the ratio of the sample (in terms of solid content) was determined to obtain the coagulation rate. The incidence rate was evaluated by the following four steps.

⊚: less than 0.01% (very small)

?: Less than 0.01 to less than 0.02% (less)

?: Less than 0.02 to 0.05% (somewhat large)

X: 0.05% or more (large)

2. Method for the determination of 4-vinylcyclohexene in oily mixtures and distillates

As the gas chromatograph, GC-2014 model manufactured by Shimadzu Corporation was used.

(1) Creating a sample

The oil-based mixtures A to F (see each of the following examples) and the distillates A to F of the oily mixture (see each of the following examples) were directly used as measurement samples.

(2) Gas chromatograph measurement conditions

Sample volume: 1 μL

Detector: FID

Injection temperature: 170 ℃

Detector temperature: 250 ° C

Column: length / inner diameter / film thickness (liquid layer) = 30 m / 0.25 mm / 0.5 탆 (DB-WAX)

Carrier gas: He 1 mL / min

Split ratio: 1/40

After maintaining the column temperature at 70 占 폚 for 5 minutes, the temperature was raised to 170 占 폚 at 10 占 폚 / min, the temperature was further raised to 230 占 폚 at 20 占 폚 / min, and the temperature was maintained at 230 占 폚 for 10 minutes.

(3) Quantitative method

4VC was diluted with cyclohexene to prepare a calibration curve, and the calibration curve was used to quantify 4VC contained in the sample.

3. Method for Measuring Average Particle Diameter of Copolymer Latex

The average particle diameter of the copolymer latex was measured as the average particle diameter by photon correlation method according to the dynamic light scattering method. On the other hand, FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) was used for the measurement.

4. Measurement of Gel Content of Copolymer Latex

The copolymer latex is dried at 80 캜 to produce a latex film. Thereafter, about 1 g of the latex film is weighed to obtain Xg. It is dissolved in 400 ml of toluene by swelling for 48 hours. Thereafter, it is filtered through a wire mesh made of stainless steel of 300 mesh, and then toluene is evaporated to dryness. After drying, the mesh weight is subtracted from the weight, and the weight of the sample after drying is weighed to Yg. The gel content (gel content) was calculated by the following formula.

Gel content (%) = Y / X * 100

≪ Examples and Comparative Examples &

Example 1

As the first polymerization, a pressure-resistant polymerization reactor equipped with a stirrer was charged with 150 parts of polymerization water, 1.5 parts of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of the monomer shown in Table 1, t-dodecylmercaptan And cyclohexene were charged, and the temperature was raised to 70 占 폚. Subsequently, the monomer shown in the second row of Table 1, t-dodecylmercaptan and cyclohexene were continuously added for 7 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%.

Subsequently, the obtained polymerization water was adjusted to pH 7 with potassium hydroxide and subjected to steam distillation at 80 占 폚. Thereby, the obtained polymerized water was separated into the copolymer latex A1 and the oil-based mixture A containing cyclohexene. A part of the obtained oily mixture A was distilled at 95 캜 to obtain a distillate A containing cyclohexene.

The concentration of 4VC in the oil-based mixture A was 3,502 ppm. Also, the concentration of 4VC in the distillate A was 2,110 ppm.

Thereafter, 150 parts of polymerized water, 1.5 parts of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of monomers shown in Table 1, t- Dodecyl mercaptan, cyclohexene, and distillate A were charged, and the temperature was raised to 70 ° C. Subsequently, the monomer shown in the second row of Table 1, t-dodecylmercaptan and the oily mixture A were continuously added for 7 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with potassium hydroxide and subjected to steam distillation at 80 캜 to obtain copolymer latex A2.

As polymerization for reuse 2, 150 parts of polymerization water, 1.5 parts of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of monomers shown in Table 1, t-dodecane Mercaptan and distillate A were charged and the temperature was raised to 70 ° C. Subsequently, the monomer shown in the second row of Table 1, t-dodecylmercaptan and the oily mixture A were continuously added for 7 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with potassium hydroxide and subjected to steam distillation at 80 ° C to obtain copolymer latex A3.

Example 2

As the first polymerization, a pressure-resistant polymerization reactor equipped with a stirrer was charged with 150 parts of polymerization water, 0.7 parts of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of the monomer shown in Table 1, t-dodecylmercaptan And cyclohexene were charged, and the temperature was raised to 68 占 폚. Subsequently, the monomer shown in the second row of Table 1 and t-dodecylmercaptan were continuously added for 8 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 97%. Subsequently, the obtained polymerization water was adjusted to pH 7 with potassium hydroxide and subjected to steam distillation at 80 占 폚. Thus, the obtained polymerized water was separated into a copolymer latex B1 and an oil-based mixture B containing cyclohexene. A part of the oil-based mixture B was distilled at 95 캜 to obtain a distillate B containing cyclohexene.

The concentration of 4VC in the oil-based mixture B was 13,119 ppm. Also, the concentration of 4VC in the distillate B was 6,074 ppm.

Thereafter, as polymerization for reuse, a pressure-resistant polymerization reactor equipped with a stirrer was charged with 150 parts of polymerization water, 0.7 part of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of monomers shown in Table 1, Mercaptan, cyclohexene and distillate B were charged and the temperature was raised to 68 ° C. Subsequently, the monomer shown in the second row of Table 1 and t-dodecylmercaptan were continuously added for 8 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 97%. Subsequently, the obtained polymerization water was adjusted to pH 7 using potassium hydroxide and subjected to steam distillation at 80 캜 to obtain a copolymer latex B2.

Example 3

The copolymer latex C1 in the first polymerization, the oil-based mixture C containing cyclohexene, the distillate C containing the cyclohexene C To obtain a copolymer latex C2 in the polymerization for reuse.

The concentration of 4VC in the oil-based mixture C was 4,188 ppm. Also, the concentration of 4VC in the distillate C was 1,962 ppm.

Example 4

As the first polymerization, a pressure-resistant polymerization reactor equipped with a stirrer was charged with 150 parts of polymerization water, 0.8 part of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of the monomer shown in Table 2, t-dodecylmercaptan And cyclohexene were charged, and the temperature was raised to 70 占 폚. Subsequently, the monomer shown in the second row of Table 2, t-dodecylmercaptan and cyclohexene were continuously added for 7 hours. Subsequently, the monomer shown in the third row of Table 2 and t-dodecylmercaptan were continuously added for 4 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with sodium hydroxide and subjected to steam distillation at 80 캜. Thus, the obtained polymerized water was separated into a copolymer latex D1 and an oil-based mixture D containing cyclohexene. The oily mixture D was distilled at 95 캜 to obtain distillate D containing cyclohexene.

The concentration of 4VC in the oil-based mixture D was 7,305 ppm. In addition, the concentration of 4VC in the distillate D was 5,162 ppm.

Thereafter, 150 parts of polymerized water, 0.8 part of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of the monomer shown in Table 1, t- Dodecyl mercaptan and cyclohexene were charged, and the temperature was raised to 70 占 폚. Subsequently, the monomer shown in the second row of Table 2, t-dodecylmercaptan and the oily mixture D were continuously added for 7 hours. Subsequently, the monomer shown in the third row of Table 2 and t-dodecylmercaptan were continuously added for 4 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with sodium hydroxide and subjected to steam distillation at 80 캜 to obtain a copolymer latex D2.

Further, in the polymerization of the copolymer latex B2 (see above Example 2), the polymerization was carried out in the same manner as in the polymerization of the re-use 2 except that cyclohexene was replaced with the oil-based mixture D and continuously added at the second stage, and the distillate B was replaced with the distillate D Except that the copolymer latex D3 was obtained by polymerization and steam distillation in the same manner.

Comparative Example 1

As the first polymerization, a pressure-resistant polymerization reactor equipped with a stirrer was charged with 150 parts of polymerization water, 0.8 part of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of the monomer shown in Table 1, t-dodecylmercaptan And cyclohexene were charged, and the temperature was raised to 68 占 폚. Subsequently, the monomer shown in the second row of Table 1 and t-dodecylmercaptan were continuously added for 8 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with sodium hydroxide and subjected to steam distillation at 80 캜. Thereby, the obtained polymerized water was separated into the copolymer latex E1 and the oil-based mixture E containing cyclohexene.

The oily mixture E was distilled at 95 캜 to obtain a distillate E containing cyclohexene.

The concentration of 4VC in the oil based mixture E was 9,950 ppm. Also, the concentration of 4VC in the distillate E was 4,135 ppm.

Thereafter, 150 parts of polymerized water, 0.8 part of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and 1 part of the monomer shown in Table 1, and a monomer of t-butyl acrylate shown in Table 3 were added to a pressure-resistant polymerization reactor equipped with a stirrer as re- Dodecyl mercaptan, cyclohexene, and an oily mixture E were charged, and the mixture was heated to 68 ° C. Subsequently, the monomer shown in the second row of Table 1 and t-dodecylmercaptan were continuously added for 8 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with sodium hydroxide and subjected to steam distillation at 80 캜 to obtain a copolymer latex E2.

In the same manner as in the polymerization of the copolymer latex A3 (see Example 1) except that the oily mixture E was used in place of the oily mixture A and the distilled product E was used in place of the distilled product A, Steam distillation yielded copolymer latex E3.

Comparative Example 2

As the polymerization for the first time, 150 parts of polymerization water, 0.9 part of dodecylbenzenesulfonic acid oxygen, 1 part of potassium persulfate, and a monomer shown in the first row of Table 3, t-dodecylmercaptan And cyclohexene were charged, and the temperature was raised to 70 占 폚. Subsequently, the monomer shown in the second row of Table 3 and t-dodecylmercaptan were continuously added for 8 hours. The polymerization was continued again, and the polymerization was terminated when the polymerization conversion rate exceeded 98%. Subsequently, the obtained polymerization water was adjusted to pH 7 with sodium hydroxide and subjected to steam distillation at 80 캜. Thus, the obtained polymerized water was separated into the copolymer latex F1 and the oil-based mixture F containing cyclohexene.

The oily mixture F was distilled at 95 캜 to obtain distillate F containing cyclohexene.

The concentration of 4VC in the oily mixture F was 14,473 ppm. Also, the concentration of 4VC in the distillate F was 6,208 ppm.

Thereafter, the copolymer latex F2 was obtained by polymerization and steam distillation in the same manner as in the polymerization of the copolymer latex F1 except that cyclohexene was changed to the oil-based mixture F as the polymerization for reuse 1.

In addition, copolymerization latex F3 was obtained by polymerization and steam distillation in the same manner as above except that cyclohexene was changed to distillate F in the polymerization of copolymer latex F1 as polymerization of reuse 2.

From the results shown in Tables 1 and 2, it can be seen that the examples of the present invention show that even when the cyclohexene is emulsion-polymerized by reuse as an oil-based mixture containing cyclohexene or an oil-based mixture as a distillate, The particle diameter of the resulting copolymer latex was almost the same as that of the first polymerization. It is clear that the productivity is good and the polymerization reproducibility is good.

From the results in Table 3, it can be seen that the amount of 4VC introduced into the polymerization system in any of Comparative Examples 1 and 2 exceeds the upper limit of the present invention, the generation rate of the aggregate is very large, and the productivity is poor. Further, the particle diameter of the copolymer latex obtained by reusing cyclohexene tends to be larger than that of the copolymer latex obtained at the first time, and it is clear that the reproducibility of the polymerization is also poor.

As described above, the method for producing the copolymer latex of the present invention is a method for producing a copolymer latex by copolymerizing 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene in the presence of an unsaturated hydrocarbon having one unsaturated bond The unsaturated hydrocarbon having one unsaturated bond is reused as the oil-based mixture itself or as a distillate of the oil-based mixture to obtain a copolymer latex having less aggregates. Therefore, the amount of the oily mixture to be discarded can be greatly reduced, and the environmental load and manufacturing cost can be greatly reduced. The copolymer latex thus obtained can be suitably used as a binder in the field of paper coating, back sizing of carpet, wood-based adhesive, electrode of battery, tire cord, etc., because the obtained copolymer latex has few aggregates as in the case of conventional copolymer latex Do.

On the other hand, the above description is provided as an example of the present invention, but this is merely an example, and should not be construed as limiting. Variations of the invention which will be apparent to those skilled in the art are included in the following claims.

Claims (8)

A process for producing a copolymer latex in which a monomer composition comprising 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene is subjected to emulsion polymerization in the presence of an unsaturated hydrocarbon having one unsaturated bond,
In the preparation of the former copolymer latex, an oleaginous mixture containing the unsaturated hydrocarbon obtained by distilling the copolymer latex after polymerization is subjected to distillation in the presence of 4-vinylcyclohexene to the total amount of the monomer composition, the unreacted unsaturated hydrocarbon and the oily mixture Is contained in the emulsion polymerization system of this time so that the proportion of the copolymer latex is 600 ppm or less. The method according to claim 1,
Wherein the oil-based mixture is further distilled by being heated to a temperature at which the unsaturated hydrocarbon is evaporated. The method according to claim 1,
Wherein the unsaturated hydrocarbon is cyclohexene. A copolymer latex characterized by being produced by the process for producing the copolymer latex according to claim 1. A process for producing a copolymer latex in which a monomer composition comprising 1,3-butadiene and other monomers copolymerizable with 1,3-butadiene is subjected to emulsion polymerization in the presence of an unsaturated hydrocarbon having one unsaturated bond,
In the preparation of the former copolymer latex, an oleaginous mixture comprising the unsaturated hydrocarbon obtained by distilling the copolymer latex after polymerization is obtained from the monomeric composition, the unused unsaturated hydrocarbon and the oily mixture in an amount based on the total amount of the oily mixture Wherein the ratio of 4-vinylcyclohexene to 4-vinylcyclohexene is 600 ppm or less. 6. The method of claim 5,
Wherein the oil-based mixture is further distilled by being heated to a temperature at which the unsaturated hydrocarbon is evaporated. 6. The method of claim 5,
Wherein the unsaturated hydrocarbon is cyclohexene. A copolymer latex produced by the process for producing the copolymer latex according to claim 5.