JPWO2019211974A1 - Statistical copolymer latex and its uses, and method for producing polymer latex - Google Patents

Abstract

To provide a technique for improving the dispersion stability of an antiaging agent in a chloroprene polymer latex and improving the heat resistance when the chloroprene polymer latex is dried.
A statistical copolymer latex containing a chloroprene monomer unit and an unsaturated nitrile monomer unit, wherein the unsaturated nitrile monomer unit is 5 to 20% by mass.
The statistical copolymer latex was diluted with a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0% by mass with respect to 100% by mass of the statistical copolymer latex. The ratio of the antiaging agent concentration in the liquid level sampling solution and the bottom surface sampling solution after centrifuging the statistical copolymer latex at 14000 rpm for 20 minutes (liquid level sampling solution / bottom surface sampling solution) is Provided are statistical copolymer latex, which is 0.6 to 1.2.

Description

The present invention relates to statistical copolymer latex and its use, and a method for producing the polymer latex.

In order to improve the heat resistance of chloroprene polymer latex, the method of adding an anti-aging agent has been used as a general method for a long time (see, for example, Patent Document 1).

Most anti-aging agents are solid at room temperature and require some ingenuity in the method of addition. There are three specific addition methods: (1) direct addition, (2) addition as an aqueous dispersion using a surfactant, and (3) addition after dissolving in an organic solvent. The method is known as a prior art (see Patent Document 2).

For example, in Patent Document 1 and Patent Document 3, an antiaging agent is added by using the method (2) of adding a surfactant as an aqueous dispersion. This method is the most common addition method as an antiaging agent and an addition method in the method for producing a chloroprene polymer latex from the viewpoint of convenience and the like.

Further, in Patent Document 4, in the production of rubber latex, the method of adding as an aqueous dispersion using the above-mentioned (2) surfactant and the method of adding after dissolving in the above-mentioned (3) organic solvent are combined. , Techniques for adding anti-aging agents are described.

Japanese Unexamined Patent Publication No. 48-178 Japanese Unexamined Patent Publication No. 2000-256512 JP-A-2007-2700057 WO2008 / 117620

As described above, in the production of rubber latex, generally three methods are used as the method of adding the antiaging agent, but in the production of chloroprene polymer latex, in general, the above (1) direct addition is used. The method or (2) the method of adding as an aqueous dispersion using a surfactant is used.

However, in the method of (1) direct addition, when the antiaging agent is water-insoluble, there is a problem that it cannot be dispersed or dissolved in latex and precipitates and precipitates as agglomerates.

Further, in the method of (2) adding as an aqueous dispersion using a surfactant, the water-insoluble antiaging agent, which is the problem of (1) above, can also be added to the latex, but water as an antiaging agent. If the difference between the particle size of the dispersion liquid and the particle size of the latex is large, the water dispersion stability of the anti-aging agent in the latex deteriorates, and there is a problem that the latex and the anti-aging agent are separated. In addition, the sedimentation rate of particles in the latex is proportional to the square of the particle size and inversely proportional to the viscosity according to Stokes' law. Therefore, when the latex has a low viscosity and the particle size of the aqueous dispersion of the antiaging agent is particularly large. , There was a problem that a large amount of anti-aging agent settled.

As described above, if the antiaging agent is settled in the latex, there is a problem that the physical properties such as elongation at break during the heat resistance test of the obtained film or the like are deteriorated.

Therefore, it is a main object of the present invention to provide a technique for improving the dispersion stability of an antiaging agent in a chloroprene polymer latex and improving the heat resistance when the chloroprene polymer latex is dried. ..

That is, the present invention is as follows.
(1) A statistical copolymer latex containing a chloroprene monomer unit and an unsaturated nitrile monomer unit having an unsaturated nitrile monomer unit content of 5 to 20% by mass.
The statistical copolymer latex was diluted with a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0% by mass with respect to 100% by mass of the statistical copolymer latex. The ratio of the antiaging agent concentration in the liquid level sampling solution and the bottom surface sampling solution after centrifuging the statistical copolymer latex at 14000 rpm for 20 minutes (liquid level sampling solution / bottom surface sampling solution). Statistical copolymer latex with a value of 0.6 to 1.2.
(2) A polymer obtained by drying the statistical copolymer latex at room temperature has a breaking elongation of 500% or more after heat treatment at 140 ° C. for 24 hours measured in accordance with JIS K6251. (1) Statistical copolymer latex described in.
(3) An RFL film obtained by drying an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the statistical copolymer latex at room temperature. The statistical copolymer latex according to (1) or (2), wherein the elongation at break after heat treatment at 140 ° C. for 24 hours, which was measured in accordance with JIS K6251, is 150% or more.
(4) The statistical copolymer latex according to any one of (1) to (3), wherein the anti-aging agent is an aromatic secondary amine-based anti-aging agent.
(5) The statistical copolymer latex according to any one of (1) to (4), wherein the content of the volatile organic solvent is 200 ppm or less.
(6) Volume change rate (ΔV) and weight change after immersion in engine oil at 140 ° C. for 72 hours, the polymer obtained by drying the statistical copolymer latex at room temperature, measured according to JIS K6258. The statistical copolymer latex according to any one of (1) to (5), wherein the value of the rate (ΔW) is in the range of −10 to + 10%.
(7) An RFL film obtained by drying an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the statistical copolymer latex at room temperature. The value of the volume change rate (ΔV) and the weight change rate (ΔW) after being immersed in the engine oil at 140 ° C. for 72 hours was in the range of -10 to + 10%, which was measured according to JIS K6258 (1). ) To (6). The statistical copolymer latex according to any one of (6).
(8) The statistical copolymer latex according to any one of (1) to (7), which is used for RFL adhesives, dipping products, adhesives, or films.
(9) An RFL adhesive, a dipping product, an adhesive, or a film using the statistical copolymer latex according to any one of (1) to (7).
(10) A polymerization step of performing emulsion polymerization using at least a chloroprene monomer unit, and
An anti-aging agent addition step of adding a water emulsified solution of an organic solvent solution containing an anti-aging agent, and
It is a method for producing a polymer latex containing
The anti-aging agent is substantially added by a hydroemulsified solution.
The polymer latex was diluted in a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0% by mass with respect to 100% by mass of the polymer latex, and the polymer. The ratio of the antiaging agent concentration in the liquid level sampling solution and the bottom surface sampling solution (liquid level sampling solution / bottom surface sampling solution) after centrifugation of the latex at 14,000 rpm for 20 minutes is 0.6 to 1.2. , A method for producing polymer latex. (11) The method for producing a polymer latex according to (10), wherein an aqueous emulsion in which an organic solvent solution containing an antioxidant, a polymerization inhibitor and an aqueous surfactant solution is added when the emulsion polymerization reaction is stopped.
(12) The method for producing a polymer latex according to (10) or (11), which comprises an organic solvent removing step of removing the organic solvent after the antiaging agent addition step.
(13) The polymer latex according to any one of (10) to (12), wherein emulsion polymerization is carried out using a chloroprene monomer unit and an unsaturated nitrile monomer unit in the polymerization step. Production method.
(14) The method for producing a polymer latex according to (13), wherein in the polymerization step, a chloroprene monomer is continuously added or intermittently added 10 times or more after the start of the polymerization reaction.
(15) A polymerization step in which emulsion polymerization is carried out using a chloroprene monomer unit and an unsaturated nitrile monomer unit, and a step in which the chloroprene monomer is continuously added or intermittently added 10 times or more after the start of the polymerization reaction.
When the polymerization reaction is stopped, a step of adding a water emulsified solution in which an organic solvent solution containing an aromatic secondary amine-based antiaging agent, a polymerization inhibitor, and an aqueous surfactant solution is added.
Including the step of removing the organic solvent.
The anti-aging agent is obtained substantially by a method of being added by a hydroemulsified solution.
Statistical copolymer latex having an unsaturated nitrile monomer unit content of 5 to 20% by mass.
In this specification, room temperature means 23 ° C. unless otherwise specified.

That is, in the present invention, first, the content of the unsaturated nitrile monomer unit is 5 to 20% by mass, preferably 6 to 17% by mass, and the chloroprene monomer unit and the unsaturated nitrile monomer unit are used. Statistical copolymer latex containing
The statistical copolymer latex was diluted with a tetrohydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0 with respect to 100% by mass of the statistical copolymer latex. By mass%, preferably 1.0 to 4.5 mass%, the antiaging agent in the liquid level sampling solution and the bottom surface sampling solution after centrifuging the statistical copolymer latex at 14000 rpm for 20 minutes. Provided are statistical copolymer latex having a concentration ratio (liquid level sampling solution / bottom surface sampling solution) of 0.6 to 1.2.
The statistical copolymer latex according to the present invention is a polymer obtained by drying the statistical copolymer latex at room temperature, and the elongation at break after heat treatment at 140 ° C. for 24 hours measured according to JIS K6251 is performed. It can be 500% or more.
The statistical copolymer latex according to the present invention is an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the statistical copolymer latex. The RFL film obtained by drying the polymer at room temperature can have a breaking elongation of 150% or more after heat treatment at 140 ° C. for 24 hours measured in accordance with JIS K6251.
In the present invention, an aromatic secondary amine-based antiaging agent can be used as the antiaging agent.
The statistical copolymer latex according to the present invention can have a volatile organic solvent content of 200 ppm or less.
The statistical copolymer latex according to the present invention is obtained by immersing the polymer obtained by drying the statistical copolymer latex at room temperature in engine oil at 140 ° C. for 72 hours, measured according to JIS K6258. The values of the volume change rate (ΔV) and the weight change rate (ΔW) can be in the range of −10 to + 10%, preferably in the range of −5 to + 5%.
The statistical copolymer latex according to the present invention is an RFL adhesive of resorcin (R) / formarin (F) / latex (L) = 10/5/85 (mass ratio) using the statistical copolymer latex. The RFL film obtained by drying the latex at room temperature was measured according to JIS K6258, and the values of the volume change rate (ΔV) and the weight change rate (ΔW) after being immersed in the engine oil at 140 ° C. for 72 hours were set to −10 to 10. It can be in the range of + 10%, preferably in the range of −5 to + 5%.

The statistical copolymer latex according to the present invention can be used for RFL adhesives, dipping products, adhesives, or films.

In the present invention, next, a polymerization step of performing emulsion polymerization using at least a chloroprene monomer unit, and
An anti-aging agent addition step of adding a water emulsified solution of an organic solvent solution containing an anti-aging agent, and
It is a method for producing a polymer latex containing
The anti-aging agent is substantially added by a hydroemulsified solution.
The polymer latex was diluted with a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0% by mass with respect to 100% by mass of the polymer latex, and the polymer. The ratio of the antiaging agent concentration in the liquid level sampling solution and the bottom surface sampling solution (liquid level sampling solution / bottom surface sampling solution) after centrifugation of the latex at 14,000 rpm for 20 minutes is 0.6 to 1.2. , Provide a method for producing a polymer latex.
In the method for producing a polymer latex according to the present invention, when the emulsion polymerization reaction is stopped, a water emulsified solution obtained by mixing an organic solvent solution containing an antioxidant, a polymerization inhibitor and an aqueous surfactant solution can be added.
In the method for producing a polymer latex according to the present invention, an organic solvent removing step of removing the organic solvent can be performed after the antiaging agent addition step.
In the method for producing a polymer latex according to the present invention, emulsion polymerization using a chloroprene monomer unit and an unsaturated nitrile monomer unit can be performed in the polymerization step.
In this case, in the polymerization step, the chloroprene monomer can be continuously added or intermittently added 10 times or more after the start of the polymerization reaction.

In the present invention, further, a polymerization step of performing emulsion polymerization using a chloroprene monomer unit and an unsaturated nitrile monomer unit, and chloroprene monomer are continuously added or intermittently added 10 times or more after the start of the polymerization reaction. Process and
When the polymerization reaction is stopped, a step of adding a water emulsified solution in which an organic solvent solution containing an aromatic secondary amine-based antiaging agent, a polymerization inhibitor, and an aqueous surfactant solution is added.
Including the step of removing the organic solvent.
The anti-aging agent is obtained substantially by a method of being added by a hydroemulsified solution.
Provided are statistical copolymer latex having an unsaturated nitrile monomer unit content of 5 to 20% by mass.

In the present invention, "JIS" means Japanese Industrial Standards (Japanese Industrial Standards).

In the present invention, the "statistical copolymer" is defined as J. C. Randall "POLYMER SEQUENCE DETERMINATION, Carbon-13 NMR Monomer" Academic Press, New York, 1977, 71-78, by Bernoulli statistical model, or by a primary or secondary Markov statistical model. It means that it is a copolymer whose monomer chain distribution can be described. The statistical copolymer containing the chloroprene monomer unit and the unsaturated nitrile monomer unit of the present embodiment is not particularly limited, but when it is composed of a binary monomer, it is not particularly limited. below Mayo-Lewis formula (I), the reactivity ratios _r 1, _{r 2} when the chloroprene monomer and M1, _{r 1} in the range of 0.3-3,000, _{r 2} is 1 × 10-5~ It can take a range of 3.0. From yet another point of view, the "statistical copolymer" in the present invention is a copolymer obtained by radical polymerization using a plurality of types of monomers. This "statistical copolymer" is a concept that includes substantially random copolymers.

According to the present invention, the dispersion stability of the antiaging agent in the chloroprene polymer latex can be improved, and the heat resistance when the chloroprene polymer latex is dried can be improved.

Hereinafter, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the embodiments described below.

<Statistical copolymer latex>
The statistical copolymer latex of the present embodiment is a statistical copolymer latex containing a chloroprene monomer unit and an unsaturated nitrile monomer unit.

The unsaturated nitrile content of the statistical copolymer latex is 5 to 20% by mass, preferably 6 to 17% by mass. Within such a range, a statistical copolymer suitable for obtaining a rubber having practically useful oil resistance, mechanical strength as a rubber, and low temperature characteristics can be obtained. If the unsaturated nitrile content is lower than this range, the oil resistance is insufficient, and if it is higher than this range, the mechanical strength of the rubber may be lowered, or the low temperature characteristics such as low temperature compression set may be lowered.

The molecular structure of the statistical copolymer is not particularly limited, but the toluene insoluble content is preferably in the range of 50 to 100% by mass. By setting the content to 50% by mass or more, it is possible to prevent a decrease in mechanical strength when the latex is dried.

Examples of the statistical copolymer latex of the present embodiment include chloroprene-acrylonitrile statistical copolymer latex, chloroprene-methacrylonitrile statistical copolymer latex, chloroprene-etacrylonitrile statistical copolymer latex, and chloroprene. -Phenylacrylonitrile Statistical copolymer latex and the like can be mentioned. Among these, chloroprene-acrylonitrile statistical copolymer latex is preferable from the viewpoint of ease of production, oil resistance, and mechanical strength.

The statistical copolymer latex according to the present embodiment is diluted with a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography is 1.0 to 100% by mass based on the statistical copolymer latex. It is 6.0% by mass, preferably 1.0 to 4.5% by mass, and is contained in the liquid level sampling solution and the bottom surface sampling solution after the statistical copolymer latex is centrifuged at 14000 rpm for 20 minutes. The anti-aging agent concentration ratio (liquid level sampling solution / bottom surface sampling solution) is 0.6 to 1.2.

In the statistical copolymer latex according to the present embodiment, the ratio of the antioxidant concentration in the liquid surface sampling solution and the bottom surface sampling solution is within this range, so that the antiaging agent is dispersed in the statistical copolymer latex. Good sex. As a result, the heat resistance of the statistical copolymer latex when it is dried can be improved.

Specifically, the statistical copolymer latex according to the present embodiment has a polymer obtained by drying the polymer at room temperature, and the elongation at break after heat treatment at 140 ° C. for 24 hours measured in accordance with JIS K6251. It is 500% or more, and has very high heat resistance when made into a film.

Further, as the statistical copolymer latex according to the present embodiment, an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the same is dried at room temperature. The RFL film thus obtained was measured in accordance with JIS K6251 and had a breaking elongation of 150% or more after being heat-treated at 140 ° C. for 24 hours, and the heat resistance of the RFL film was very high.

Further, the statistical copolymer latex according to the present embodiment has a volume change rate after immersion in engine oil at 140 ° C. for 72 hours, which is a polymer obtained by drying the polymer at room temperature in accordance with JIS K6258. The values of (ΔV) and the weight change rate (ΔW) are in the range of −10 to + 10%, preferably in the range of −5 to + 5%, and the oil resistance when formed into a film is also very high.

In addition, as the statistical copolymer latex according to the present embodiment, an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the same is applied at room temperature. The RFL film obtained by drying was measured according to JIS K6258, and the values of volume change rate (ΔV) and weight change rate (ΔW) after immersion in engine oil at 140 ° C. for 72 hours were -10 to + 10%. It is in the range of -5 to + 5%, and the oil resistance when made into an RFL film is also very high.

As the anti-aging agent that can be used in the present embodiment, one or two or more known anti-aging agents can be freely selected and used as long as the effects of the present technology are not impaired. For example, phenolic and imidazole antiaging agents can be mentioned. Among these, in particular, in the present embodiment, it is preferable to use an aromatic secondary amine-based antiaging agent. As for the aromatic secondary amine-based anti-aging agent that can be used in the present embodiment, one or more known aromatic secondary amine-based anti-aging agents are free as long as the effects of the present technology are not impaired. For example, N-phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonyl). Amid) Diphenylamine, N, N'-di-2-naphthyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl- Examples thereof include N'-(1,3-dimethylbutyl) -p-phenylenediamine, N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, and the like.

The statistical copolymer latex according to the present embodiment preferably has a volatile organic solvent content of 200 ppm or less. By suppressing the content of the volatile organic solvent within this range, it is possible to prevent adverse effects on the human body and reduce the environmental load.

<Use of statistical copolymer latex>
The statistical copolymer latex according to the present embodiment can be suitably used for RFL adhesives, dipping products, adhesives, or films by utilizing its high heat resistance and the like. Further, the statistical copolymer latex according to the present embodiment is obtained after adjusting the pH and making a statistical copolymer through steps such as freeze-coagulation, washing with water, and hot air drying in a conventional method. The polymer is suitably used as a material for rubber products used for transmission belts, conveyor belts, air springs, seals, packings, anti-vibration materials, hoses, rubber rolls, wipers, boots, rubberized cloths, sponge products, rubber linings, etc. can do.

(RFL adhesive, adhesive)
Chloroprene polymer latex is used as an RFL adhesive for surface treatment by immersing reinforcing fibers in order to enhance the adhesiveness with rubber. Belt applications, which are the applications of reinforcing fibers, require particularly excellent durability in addition to adhesiveness, and there is a high demand for mechanical strength, oil resistance, and heat resistance. Therefore, the development of chloroprene polymer latex, which exhibits even better mechanical strength, oil resistance, and heat resistance, is eagerly desired. In addition, chloroprene polymer latex is used as an adhesive for a wide range of materials such as civil engineering, plywood, furniture, shoes, wet suits, and automobile interior materials because it has contact properties and is excellent in initial adhesive strength. Among these, the demand as a one-component adhesive for polyurethane foam, which is widely used as a material for furniture and automobile interior materials, is expanding significantly. In particular, for automobile interior materials, it is desired to develop a chloroprene polymer latex having excellent heat resistance that can withstand a temperature rise in an automobile interior.

The statistical copolymer latex of the present embodiment can increase the heat resistance of the adhesive. This makes it possible to produce an RFL adhesive or an adhesive that is superior to the conventional chloroprene polymer latex.

(Immersion product)
Rubber latex containing natural rubber and synthetic rubber such as chloroprene polymer, isoprene rubber, and nitrile butadiene rubber is dip-molded for medical surgical gloves, inspection gloves, industrial gloves, balloons, catheters, rubber boots, reinforcing fibers, etc. Used as a raw material for products. In particular, rubber latex for medical surgical gloves, inspection gloves, industrial gloves, and household gloves is made of chloroprene polymer, isoprene rubber, and nitrile butadiene rubber in order to avoid the problem of shock symptoms (anaphylactic) due to allergies to natural rubber. Synthetic rubber such as, is preferred. Among them, the chloroprene polymer has an excellent balance of flexibility and mechanical strength and exhibits high chemical resistance, so that it is used for industrial gloves having resistance to various chemicals. In recent years, the demand for chemical-resistant gloves that can withstand use in high-temperature environments and low-temperature environments has increased, and the development of chloroprene polymer latex having better heat resistance than before has been desired.

The statistical copolymer latex of the present embodiment can enhance the heat resistance of the immersed product. This makes it possible to manufacture industrial gloves that can withstand use in a high temperature environment, which was difficult with conventional CR.

(Transmission belt and conveyor belt)
Specific examples of the transmission belt and the conveyor belt include a flat belt, a conveyor belt, a timing belt, a V belt, a rib belt, and a round belt. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, bending fatigue resistance, and heat resistance of the transmission belt and the conveyor belt. As a result, it is possible to manufacture a belt that can withstand use in an environment exposed to scattered oil and a high temperature environment, which was difficult with conventional materials.

(Air spring)
The air spring is a spring device that utilizes the elasticity of compressed air, and is used for air suspensions of automobiles, buses, trucks, and the like. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, durable fatigue resistance, settling resistance (low compression set resistance), and heat resistance of the air spring. As a result, it is possible to manufacture an air spring that can withstand use in an environment with a lot of oil stains and a high temperature environment, which was difficult with conventional materials.

(Seal and packing)
Seals are parts that prevent liquid and gas leaks and dust and foreign matter such as rainwater and dust from entering the inside of machines and devices.Specifically, gaskets used for fixing purposes and moving parts There is packing used for moving parts. In gaskets in which the seal portion is fixed with bolts or the like, various materials are used for soft gaskets such as O-rings and rubber sheets according to the purpose. In addition, packing is used for a shaft of a pump or a motor, a rotating part such as a moving part of a valve, a reciprocating part such as a piston, a connecting part of a coupler, and a water stop part of a water faucet. The statistical copolymer of the present embodiment can enhance the mechanical strength and oil resistance of the seal. This makes it possible to produce seals for non-polar fluids such as engine oils and gear oils, which was difficult with conventional materials. In addition to the above, the statistical copolymer of the present embodiment also provides good settling resistance (low compression set resistance) and heat resistance, so that it can be sealed even when used for a long period of time or in a high temperature environment. The shape of the is hard to change and good sealing performance can be obtained. In particular, settling resistance (low compression set resistance) at low and high temperatures is important for this application.

(Vibration isolation material)
Anti-vibration material is rubber that prevents the transmission and spread of vibration. Specifically, it is a torsional damper and engine mount for absorbing vibration when driving an engine for automobiles and various vehicles to prevent noise. , Muffler hanger, etc. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, bending fatigue resistance, and heat resistance of the vibration isolator. As a result, it is possible to produce anti-vibration rubber that can withstand use in an environment where oil is scattered or in a high temperature environment, which was difficult with conventional materials.

(hose)
The hose is a bendable pipe, and specifically, there are high / low pressure hoses for water supply, oil supply, air supply, steam, and hydraulic pressure. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, sag resistance (low compression set resistance), and heat resistance of the hose. This makes it possible to manufacture a hose that comes into direct contact with a non-polar fluid, which was difficult with conventional materials, and a hose that can withstand use in a high temperature environment.

(Rubber roll)
A rubber roll is a roll manufactured by adhesively coating a metal core such as an iron core with rubber. Specifically, it is used for papermaking, various metal manufacturing, printing, general industrial use, paddy shaving, and other agricultural machinery. There are rubber rolls that meet the required characteristics of various applications such as for use and food processing. It is used in an environment where oil adheres when manufacturing industrial materials and products for iron making and paper making, and when plating products such as gold, silver, nickel, chromium and zinc, acid is used. It may be exposed to alkali. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, settling resistance (low compression set resistance), and heat resistance of the rubber roll. This makes it possible to manufacture a rubber roll that can withstand use in an environment where oil adheres or in a high temperature environment, which was difficult with conventional CR.

(Wiper)
Specifically, the wiper is used for windshields, rear glasses, etc. of automobiles, trains, aircraft, ships, construction machinery, and the like. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, durable fatigue resistance, settling resistance (low compression set resistance), and heat resistance of the wiper. This makes it possible to manufacture a wiper that can withstand use in an environment with a lot of oil stains and a high temperature environment, which was difficult with conventional materials.

(boots)
Boots are bellows-shaped members whose outer diameter gradually increases from one end to the other. Specifically, boots and balls for constant velocity joint covers for protecting drive parts such as automobile drive systems. There are boots for joint covers (dust cover boots), boots for rack and pinion gear, etc. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, and endurance fatigue resistance of the boot. This makes it possible to manufacture boots that are more reliable against non-polar liquids such as oil and grease contained inside than conventional materials. Further, since the statistical copolymer of the present embodiment has excellent settling resistance (low compression set resistance) and heat resistance, a caulked portion for preventing leakage of oil contained inside such as a metal band. Deformation is unlikely to occur.

(Rubber cloth)
Rubberized cloth is a composite material of rubber and cloth woven fabric (fiber), which is made by sticking rubber to cloth. Specifically, it is widely used for rubber boats, tent materials, clothing such as rain feathers, waterproof sheets for construction, cushioning materials, etc. It is used. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, and heat resistance of the rubberized cloth. This makes it possible to produce a rubberized cloth that can withstand use in an environment where oil is scattered or in a high temperature environment, which was difficult with conventional materials.

(Sponge product)
The sponge is a porous substance having innumerable fine holes inside, and specific examples thereof include anti-vibration members, sponge seal parts, wet suits, and shoes. The statistical copolymer of the present embodiment can enhance the mechanical strength, oil resistance, and heat resistance of the sponge product. As a result, it is possible to manufacture a sponge product that is less likely to cause swelling deformation and discoloration due to oil, which was difficult with conventional materials, and can withstand use in a high temperature environment.

(Rubber lining)
The rubber lining is used for the purpose of preventing metal corrosion by adhering a rubber sheet to a metal surface such as a pipe or a tank. Rubber linings are also used in places where electricity resistance, wear resistance, and heat resistance are required. The statistical copolymer of the present embodiment can enhance the oil resistance and heat resistance of the rubber lining. This makes it possible to prevent corrosion of pipes and tanks with oil, which was difficult with conventional materials.

<Manufacturing method of polymer latex>
The method for producing a polymer latex according to the present embodiment is a method in which (1) a polymerization step and (2) an antiaging agent addition step are at least performed. Further, (3) the step of removing the organic solvent and other steps generally used in the method for producing the polymer latex can also be performed. Hereinafter, each step will be described in detail.

(1) Polymerization Step In the polymerization step, emulsion polymerization is carried out using at least 2-chloro-1,3-butadiene (hereinafter abbreviated as "chloroprene") monomer unit. More specifically, in this polymerization step, chloroprene homopolymerization or copolymerization with one or more monomers copolymerizable with chloroprene is performed.

Examples of the monomer copolymerizable with chloroprene in the present embodiment include 2,3-dichloro-1,3-butadiene, 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, and methylmethacrylate. Ethylmethacrylate, propylmethacrylate (total isomer), butylmethacrylate (total isomer), 2-ethylhexylmethacrylate, isobornylmethacrylate, methacrylic acid, benzylmethacrylate, facrylic acidate , Ethyl acrylate, propyl acrylate (total isomer), butyl acrylate (total isomer), 2-ethylhexyl acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate, phenyl acrylic Acids, styrene, and glycidylmethacrylate, 2-hydroxyethylmethacrylate, hydroxypropylmethacrylate (total isomer), hydroxybutylmethacrylate (total isomer), N, N-dimethylaminoethylmethacrylate Salt, N, N-diethylaminoethyl methacrylate, triethylene glycol methacrylate, itaconic anhydride, itaconic acid, glycidyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate (total isomer), Hydroxybutyl acrylate (total isomer), N, N-dimethylaminoethyl acrylate, N, N-path ethyl aminoethyl acrylate, triethylene glycol acrylate, methacrylamide, N-methylacrylamide, N , N-Dimethylacrylamide, N-tertiary butylmethacrylicamide, Nn-butylmethacrylicamide, N-methylolmethacrylicamide, N-ethylolmethacrylicamide, N-ternarybutylacrylamide, Nn-butyl Acrylamide, N-methylol acrylamide, N-ethylol acrylamide, vinyl benzoic acid (total isomer), diethylaminocitylene (total isomer), alpha-ethylvinyl benzoic acid (total isomer), diethylaminoalpha-methylstyrene (total isomer) Body), p-vinylbenzenesulfonic acid, p-vinylbenzenesulfonic acid sodium salt, trimethoxysilylpropylmethacrylate, triethoxysilylpropylmethacrylate, tributoxysilylpropylmethacrylate, dimethoxymethylsilylpropylmethacrylate, Diethoxymethylsilylpropylmethacrylate, dibutoxymethylsilylpropylmethacrylate Luate, diisopropoxymethylsilylpropylmethacrylate, dimethoxysilylpropylmethacrylate, diethoxysilylpropylmethacrylate, dibutoxysilylpropylmethacrylate, diisopropoxysilylpropylmethacrylate, trimethoxysilylpropyl Acrylate, triethoxysilylpropyl acrylate, tributoxysilylpropyl acrylate, dimethoxymethylsilylpropyl acrylate, diethoxymethylsilylpropyl acrylate, dibutoxymethylsilylpropyl acrylate, diisopropoxymethyl Cyrilpropyl acrylate, dimethoxysilylpropyl acrylate, diethoxysilylpropyl acrylate, dibutoxysilylpropyl acrylate, diisopropoxysilylpropyl acrylate, vinyl acetate, vinyl butyrate, vinyl benzoate, vinyl chloride , Vinyl fluoride, vinyl bromide, maleic anhydride, N-phenylmaleimide, N-butylmaleimide, N-vinylpyrrolidone, N-vinylcarbazole, ethylene, propylene, unsaturated nitrile monomer (acrylonitrile, methacrylonitrile, (Etacrylonitrile, phenylacrylonitrile, etc.) and the like can be mentioned.

The polymerization method is not particularly limited, but the raw material monomer may be polymerized by a generally used emulsion polymerization method in the presence of a surfactant, a polymerization initiator, a molecular weight modifier and the like.

The surfactant (emulsification / dispersant) that can be used in the present embodiment is not particularly limited as long as the effect of the present technology is not impaired, and the anion type, nonion type, etc. used in the usual emulsion polymerization of chloroprene. Various types such as cation type can be used. Anionic surfactants are preferred because of the stability of the resulting latex, for example rosinates, alkyl sulfonate salts having 8 to 20 carbon atoms, alkyl sulfate salts, alkylaryl sulfate salts, sodium naphthalene sulfonate and formaldehyde. , Alkyldiphenyl ether disulfonate sodium and the like. Among the anionic surfactants, it is particularly preferable to use an alkali metal rosinate because the latex is particularly stable. Rosinic acid is a mixture of resin acids, fatty acids and the like. Resin acids include abietic acid, neoavietic acid, palastolic acid, pimaric acid, isopimaric acid, dehydroabietic acid, dihydropimaric acid, dihydroisopimaric acid, secodehydroabietic acid, dihydroabietic acid, etc., and fatty acids include dihydroabietic acid. , Oleic acid, linoleic acid, etc. are included. The composition of these components changes depending on the difference in the rosin collection method classified into gum rosin, wood rosin, and tall rosin, the origin and species of pine trees, distillation purification, and disproportionation (disproportionation) reaction, and is limited in the present invention. Not done. Considering emulsion stability and ease of handling, the use of sodium salt or potassium salt is preferable.

The amount of the surfactant added is preferably 0.2 to 20 parts by mass, more preferably 2 to 10 parts by mass, based on 100 parts by mass of the total of the chloroprene monomer and other monomers. When the amount is 0.2 parts by mass or more, the monomer can be sufficiently emulsified, and when the amount is 20 parts by mass or less, it is possible to prevent the surfactant from blooming on the surface of the obtained film.

As the polymerization initiator that can be used in the present embodiment, one or more known polymerization initiators can be freely used as long as the effects of the present technology are not impaired. For example, potassium persulfate, ammonium persulfate, benzoyl peroxide, sodium persulfate, hydrogen peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl peroxyoctate, t-butyl peroxyneodecanoate, t. -Butyl peroxyisobutyrate, t-amylperoxypivalate, t-butylperoxypivalate, di-isopropylperoxydicarbonate, dicyclohexylperoxydicarbonate, dicumyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, potassium peroxydisulfate, Organic peroxides such as ammonium peroxydisulfate, butyl di-t-hydroxide, dicumyl hyponitrate, 2,2-azobis (isobutyronitrile), 2,2'-azobis (2-cyano-2-butane) ), Dimethyl 2,2'-azobisdimethylisobutyrate, 4,4'-azobis (4-cyanopentanoic acid), 1,1'-azobis (cyclohexanecarbonitrile), 2- (t-butylazo) -2 -Cyanopropane, 2,2'-azobis [2-methyl-N- (1,1) -bis (hydroxymethyl) -2-hydroxyethyl] propionamide, 2,2'-azobis [2-methyl-N- Hydroxyethyl)]-propionamide, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis ( N, N'-dimethylene isobutylamine), 2,2'-azobis (2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide), 2,2'-azobis (2-Methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2-azobis (Isobutylamide) dihydrate), azo-based initiators such as 2,2'-azobis (2,2,4-trimethylpentane) and 2,2'-azobis (2-methylpropane) can be mentioned.

In the case of emulsion polymerization, it is also possible to use a polymerization co-catalyst. The polymerization co-catalyst that can be used in the present embodiment is not particularly limited as long as the effects of the present invention are not impaired, and one or more known polymerization co-catalysts can be freely used. For example, L-ascorbic acid, tartrate acid, sodium bisulfite, zinc-or sodium-formaldehyde-sulfoxylate longalite, formdiamine sulfinic acid, glucose, formalin, sodium anthraquinone β-sulfonate, ferrous sulfate, copper sulfate, etc. Examples thereof include sodium bisulfite and thiourea.

In the production method of this embodiment, a chain transfer agent can be used to control the molecular weight. The chain transfer agent that can be used in the present embodiment is not particularly limited as long as the effects of the present invention are not impaired, and one or more known chain transfer agents can be freely used. For example, long-chain alkyl mercaptans such as n-dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl mercaptan, xanthogen compounds such as diisopropylxantogen disulfide and diethylxanthogen disulfide, iodoform, benzyl1-pyrrol dithiocarbamate (also known as benzyl1-pyrrole). Carbodithioate), 1-benzyl-N, N dimethyl-4-aminodithiobenzoate, 1-benzyl-4-methoxydithiobenzoate, 1-phenylethylimidazole dithiocarbamate (also known as 1-phenylethylimidazole carbodithioate), benzyl -1- (2-Pyrrolidinone) dithiocarbamate (also known as benzyl-1- (2-pyrrolidinone) carbodithioate), benzylphthalimidyldithiocarbamate (also known as benzylphthalimidylcarbodithioate), 2-cyanoprop-2-yl -1-pyrroledithiocarbamate (also known as 2-cyanoprop-2-yl-1-pyrrolecarbodithioate), 2-cyanobut-2-yl-1-pyrroledithiocarbamate (also known as 2-cyanobut-2-yl-1-pyrrole) Benzyl-1-imidazole dithiocarbamate (also known as benzyl-1-imidazole carbodithioate), 2-cyanoprop-2-yl-N, N-dimethyldithiocarbamate, benzyl-N, N-diethyldithiocarbamate, Cyanomethyl-1- (2-pyrrolidone) dithiocarbamate, 2- (ethoxycarbonylbenzyl) prop-2-yl-N, N-diethyldithiocarbamate, benzyldithioate, 1-phenylethyldithiobenzoate, 2-phenylprop-2 -Ildithiobenzoate, 1-acetic acid-1-yl-ethyldithiobenzoate, 1- (4-methoxyphenyl) ethyldithiobenzoate, benzyldithioacetate, ethoxycarbonylmethyldithioacetate, 2- (ethoxycarbonyl) prop-2- Ildithiobenzoate, 2-cyanoprop-2-yldithiobenzoate, dithiobenzoate, tert-butyldithiobenzoate, 2,4,4-trimethylpent-2-yldithiobenzoate, 2- (4-chlorophenyl) -prop-2- Ildithiobenzoate, 3-vinylbenzyldithiobenzoate, 4-vinylbenzyldithiobenzoate, benzyldiethoxyphosphite Nildithioformate, tert-butyltrithioperbenzoate, 2-phenylprop-2-yl-4-chlorodithiobenzoate, naphthalene-1-carboxylic acid-1-methyl-1-phenyl-ethyl ester, 4-cyano-4 -Methyl-4-thiobenzylsulfanylbutyric acid, dibenzyltetrathioterephthalate, carboxymethyldithiobenzoate, poly (ethylene oxide) having a dithiobenzoate terminal group, 4-cyano-4-methyl-4-thiobenzylsulfanylbutyric acid terminal group Poly (ethylene oxide), 2-[(2-phenylethanthi oil) sulfanyl] propanoic acid, 2-[(2-phenylethanthi oil) sulfanyl] succinic acid, 3,5-dimethyl-1H-pyrazol- 1-Carbodithioate Potassium, Cyanomethyl-3,5-dimethyl-1H Pyrazole-1-Carbodithioate, Cyanomethylmethyl- (phenyl) dithiocarbamate, benzyl-4-chlorodithiobenzoate, Phenylmethyl-4-chlorodithiobenzoate , 4-Nitrobenzyl-4-chlorodithiobenzoate, phenylprop-2-yl-4-chlorodithiobenzoate, 1-cyano-1-methylethyl-4-chlorodithiobenzoate, 3-chloro-2-butenyl-4- Chlorodithiobenzoate, 2-chloro-2-butenyl dithiobenzoate, benzyldithioacetate, 3-chloro-2-butenyl-1H pyrrol-1-dithiocarboxylic acid, 2-cyanobutane-2-yl 4-chloro-3,5 -Dimethyl-1H-pyrazole-1-carbodithioate, cyanomethylmethyl (phenyl) carbamodithioate, 2-cyano-2-propyldodecyltrithiocarbonate, dibenzyltrithiocarbonate, butylbenzyltrithiocarbonate , 2-[[(Butylthio) thioxomethyl] thio] propionic acid, 2-[[(dodecylthio) thioxomethyl] thio] propionic acid, 2-[[(butylthio) thioxomethyl] thio] succinic acid, 2-[[(dodecylthio)) Thioxomethyl] thio] succinic acid, 2-[[(dodecylthio) thioxomethyl] thio] -2-methylpropionic acid, 2,2'-[carbonothio oil bis (thio)] bis [2-methylpropionic acid], 2- Amino-1-methyl-2-oxoethylbutyltrithiocarbonate, benzyl2-[(2-hydroxyethyl) amino] -1-methyl-2- Oxoethyltrithiocarbonate, 3-[[[(tert-butyl) thio] thioxomethyl] thio] propionic acid, cyanomethyldodecyltrithiocarbonate, diethylaminobenzyltrithiocarbonate, dibutylaminobenzyltrithiocarbonate, etc. Known chain transfer agents such as thiocarbonyl compounds can be used.

The polymerization temperature in the emulsion polymerization is not particularly limited, but is preferably 0 to 59 ° C, particularly preferably 5 to 55 ° C. By setting the polymerization temperature to 5 ° C. or higher, the thickening of the emulsion and the efficiency of the initiator can be further improved. In addition, since the boiling point of chloroprene is about 59 ° C. under normal pressure, by setting the polymerization temperature to 55 ° C. or lower, the reaction solution suddenly boils without catching up with the heat removal even when heat is generated due to abnormal polymerization or the like. The situation can be avoided. More preferably, by keeping the polymerization temperature at 30 to 45 ° C., a polymer having excellent mechanical properties can be obtained.

When emulsion polymerization is carried out using a chloroprene monomer unit and an unsaturated nitrile monomer unit in the polymerization step, the chloroprene monomer may be continuously added or intermittently added 10 times or more after the start of the polymerization reaction. preferable. Chloroprene has a faster reaction rate than unsaturated nitriles. Therefore, in the polymerization system, the chloroprene monomer is consumed faster than the unsaturated nitrile monomer. If the ratio of the chloroprene monomer to the unsaturated nitrile monomer is significantly biased, the oil resistance of the statistical copolymer produced may decrease. In the production method of the present embodiment, the chloroprene monomer and the unsaturated nitrile monomer in the polymerization system are simply added by continuously adding the chloroprene monomer reduced by the polymerization reaction or by intermittently adding the chloroprene monomer 10 times or more. The ratio of the monomers can be kept constant. The statistical copolymer produced by the production method of the present embodiment is also excellent in mechanical strength.

In the production method of the present embodiment, in the case of intermittent addition of 10 times or more, the amount of the chloroprene monomer added after the start of the polymerization reaction is the total of the chloroprene monomer and the unsaturated nitrile monomer. It is preferably 10 parts by mass or less with respect to 100 parts by mass. In the case of intermittent addition, the addition rate is preferably 2 parts by mass / minute or less. Within such a range, a statistical copolymer having excellent oil resistance and mechanical strength can be obtained. Here, keeping the ratio of the unreacted chloroprene monomer and the unsaturated nitrile monomer in the polymerization solution constant during the polymerization is not suitable for the total amount of the chloroprene monomer and the unsaturated nitrile monomer. The mass ratio of the saturated nitrile monomer is preferably within ± 10% of the target value. For example, when the mass ratio of the unsaturated nitrile monomer to the total of the unreacted chloroprene monomer and the unsaturated nitrile monomer in the polymerization solution is kept at 0.50 during the polymerization, it is preferably 0.45-0. It means to keep it in the range of .55.

In the production method of the present embodiment, the polymerization rate (polymerization conversion rate) is preferably in the range of 60 to 100%. The polymerization reaction is stopped by adding a polymerization inhibitor. By setting the polymerization rate to 60% or more, the strength of the obtained film or the like can be improved.

The polymerization inhibitor that can be used in the present embodiment is not particularly limited as long as the effect of the present invention is not impaired, and one or more known polymerization inhibitors can be freely used. For example, thiodiphenylamine, 4-tert-butylcatechol, 2,2-methylenebis-4-methyl-6-tertiary butylphenol, diethylhydroxylamine and the like can be mentioned.

In the production method of the present embodiment, the unreacted monomer may be removed and concentrated by a known method such as heating under reduced pressure.

Further, in the polymer latex obtained by the production method of the present embodiment, a freeze stabilizer, an emulsion stabilizer, a viscosity modifier, an antioxidant, a preservative, etc. are optionally added after polymerization as long as the effects of the present invention are not impaired. Can be added to.

(2) Anti-aging agent addition step The anti-aging agent addition step is a step of adding a water emulsified solution of an organic solvent solution containing an anti-aging agent. In the production method of the present invention, the anti-aging agent is substantially added by the hydroemulsified liquid. Here, substantially means that 70% by mass or more, preferably 95% by mass or more, and most preferably 100% by mass of the total anti-aging agent is added as a water emulsion.

The organic solvent that can be used in the antiaging agent addition step is not particularly limited as long as the effect of the present technology is not impaired, and one or more known organic solvents can be freely used. For example, aromatic hydrocarbon solvents such as benzene, toluene and xylene; alicyclic hydrocarbon solvents such as cyclopentane, cyclopentene and cyclohexane; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; chloroprene, methylene chloride, chloroform, etc. Examples thereof include halogenated hydrocarbon solvents such as ethylene dichloride; ether solvents such as diethyl ether, tetrahydrofuran and tetrahydropyran; and the like.

The amount of the organic solvent used in the process of adding the anti-aging agent is not particularly limited as long as the effect of the present technology is not impaired, and can be freely set as long as the anti-aging agent to be used can be completely dissolved.

The anti-aging agent that can be used in the process of adding the anti-aging agent is not particularly limited as long as the effect of the present technology is not impaired, and one or more known anti-aging agents can be freely used. Since the specific type is the same as the antiaging agent that can be used for the statistical copolymer latex described above, the description thereof is omitted here.

The amount of the anti-aging agent added in the process of adding the anti-aging agent is preferably 2.0 to 9.0 parts by mass with respect to 100 parts by mass in total of the chloroprene monomer and other monomers. By setting the amount to 2.0 parts by mass or more, the heat resistance of the obtained film can be improved. By setting the content to 9.0 parts by mass or less, it is possible to prevent the anti-aging agent from blooming on the surface of the obtained film and deteriorating physical properties such as elongation at break.

The surfactant used for emulsifying an organic solvent solution containing an antiaging agent is not particularly limited as long as the effect of the present technology is not impaired, and one or more known surfactants may be freely used. it can. Since the specific type is the same as that of the surfactant used for the statistical copolymer latex described above, the description thereof is omitted here.

The anti-aging agent addition step can be performed after the above-mentioned polymerization step, but when the emulsion polymerization reaction is stopped in the polymerization step, an organic solvent solution containing an anti-aging agent, a polymerization inhibitor and a surfactant aqueous solution are mixed. It is more preferable to add a water emulsion. By adding an organic solvent solution containing an antioxidant when the polymerization is stopped, the polymerization can be stopped and the antiaging agent can be dispersed in the latex at the same time, shortening the manufacturing process and reducing the amount of the organic solvent used. be able to.

(3) Organic Solvent Removal Step The organic solvent removing step is a step of removing the organic solvent used for adding the anti-aging agent in the anti-aging addition step. When the emulsion polymerization reaction is stopped and the water emulsion of the organic solvent solution containing the antiaging agent is added at the same time, the unreacted monomer and the organic solvent can be removed at the same time in this step. By performing the organic solvent removing step, it is possible to prevent the produced polymer latex from adversely affecting the human body and reduce the environmental load.

The method for removing the organic solvent is not particularly limited as long as the effect of the present technology is not impaired, and one or more known removal methods can be freely used. For example, methods such as vacuum distillation, atmospheric distillation, and steam distillation can be adopted. The content of the organic solvent is preferably 200 ppm or less in the latex.

The polymer latex produced by the production method of the present embodiment is diluted with a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography is 1.0 to 6 with respect to 100% by mass of the polymer latex. It is 0.0% by mass, preferably 1.0 to 4.5% by mass, and the concentration of the antioxidant in the liquid level sampling solution and the bottom surface sampling solution after the polymer latex is centrifuged at 14000 rpm for 20 minutes. The ratio (liquid level sampling solution / bottom surface sampling solution) is 0.6 to 1.2. Here, the liquid level sampling liquid is a latex liquid carefully collected with a syringe from the liquid surface of the centrifuge tube after centrifugation, and the bottom sampling liquid is a syringe carefully collected from the bottom surface of the tube after centrifugation. It is a latex liquid collected in.

Since the ratio of the anti-aging agent concentration in the liquid surface sampling liquid and the bottom surface sampling liquid is within this range, the dispersibility of the anti-aging agent in the polymer latex produced by the production method of the present embodiment is good. As a result, the heat resistance when the polymer latex is dried can be improved.

Specifically, the polymer latex produced by the production method of the present embodiment is obtained by drying the polymer at room temperature, and the polymer is measured in accordance with JIS K6251 at 140 ° C. and stretched at break after heat treatment for 24 hours. However, it is 500% or more, and the heat resistance when made into a film is very high.

Further, the polymer latex produced by the production method of the present embodiment contains an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the same. The RFL film obtained by drying at room temperature has a breaking elongation of 150% or more after being heat-treated at 140 ° C. for 24 hours measured in accordance with JIS K6251, and the heat resistance of the RFL film is also very high.

Hereinafter, the present invention will be described in more detail based on examples. The examples described below show examples of typical examples of the present invention, and the present invention is not limited to the following examples.

<Manufacturing of polymer latex>
[Example 1]
20 parts by mass of chloroprene monomer, 20 parts by mass of acrylonitrile monomer, 150 parts by mass of pure water, potassium disproportionate (Harima Kasei Co., Ltd.) in a polymerization can with an internal volume of 3 liters equipped with a heating / cooling jacket and a stirrer. (Manufactured) 5.0 parts by mass, potassium hydroxide 0.4 parts by mass, and sodium salt of β-naphthalene sulfonate formalin condensate (manufactured by Kao Co., Ltd.) 1.0 part by mass were added. 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out at a polymerization temperature of 40 ° C. under a nitrogen stream. The chloroprene monomer is divided into specific densities of 0.989, 0.993, 1.000, 1.007, 1.013, 1.020, 1.026, 1.032, 1.038 and 1.042. When 1.046 and 1.050 were reached, 5.0 parts by mass of each were added 12 times in total. When the polymerization rate with respect to the total amount of chloroprene and acrylonitrile reached 82%, a water emulsified solution (polymerization terminator solution) of an organic solvent solution containing an antioxidant was added to terminate the polymerization. The water emulsified solution (polymerization terminator) of the organic solvent solution contains 0.1 parts by mass of thiodiphenylamine, which is a polymerization terminator, 0.1 parts by mass of diethylhydroxylamine, and 4,4'-bis (α,) which is an antioxidant. 4.8 parts by mass of α-dimethylbenzyl) diphenylamine was completely dissolved in 9.6 parts by mass of chloroprene, which is an organic solvent, and 0.2 parts by mass of sodium lauryl sulfate, which is a surfactant, and β-naphthalene sulfonate formarin condensate. It was prepared by emulsification using 0.2 parts by mass of sodium salt and 4.0 parts by mass of pure water.
Next, the unreacted monomer and the organic solvent were removed and concentrated by vacuum distillation to adjust the solid content of the polymer latex to 50% by mass.

During the polymerization, the polymerization solution was sampled 10 times or more periodically to measure the unreacted chloroprene monomer and acrylonitrile monomer contained in the polymerization solution. The mass ratio of acrylonitrile monomer to total body was always within ± 10% of the target value.

<Recovery of copolymer by freeze-drying>
After freezing 12 g of the polymer latex produced above at −30 ° C. for 3 hours or longer, it was dried at room temperature 23 ° C. for 16 hours or longer using a vacuum dryer to obtain a solid copolymer.

<Measurement of the amount of monomer in the polymerization solution>
1.0 g of the polymer solution sampled in a 25 ml volumetric flask was weighed, diluted with tetrahydrofuran to 25 ml, and the sample obtained by stirring was used, and the measurement was performed by a usual quantitative analysis method using a gas chromatograph and a calibration curve. (Hereafter, the same applies).
(Measurement conditions for gas chromatograph)
The gas chromatograph was performed under the following measurement conditions.
・ Equipment: GC-2010 (manufactured by Shimadzu Corporation)
-Column used: DB-1, 0.25 mm x 60 m
-Carrier gas: Helium-Column temperature: Raise from 50 ° C to 100 ° C at 5 ° C / min-Inlet temperature: 270 ° C
・ Detector: FID
・ Detector temperature: 300 ℃
・ Injection volume: 1 μL

The polymerization rate of the chloroprene-acrylonitrile statistical copolymer from the start of polymerization to a certain time was calculated from the dry weight (solid content concentration, the same applies hereinafter) by heating and air-drying the chloroprene-acrylonitrile statistical copolymer latex. .. Specifically, it was calculated from the following general formula (II). The dry weight during the polymerization was determined by adding a small amount of a polymerization inhibitor that does not affect the dry weight to the latex. In the formula, the solid content concentration was determined by heating 2 g of the sampled emulsion polymerization solution at 130 ° C. to remove the solvent (water), volatile chemicals and raw materials, and then removing the volatile content from the weight change before and after heating. Minute concentration (% by mass). The total amount charged and the evaporation residue were calculated from the polymerization formulation. The total amount charged is the total amount of raw materials, reagents, and solvent (water) charged in the polymerization can from the start of polymerization to a certain time. The evaporation residue represents the weight of the chemicals and raw materials charged from the start of polymerization to a certain time, which remain as solids together with the polymer without volatilizing under the condition of 130 ° C. The amount of the monomer charged is the total amount of the monomer initially charged in the polymerization can and the amount of the monomer divided from the start of the polymerization to a certain time. The monomer referred to here is the total amount of the chloroprene monomer and the acrylonitrile monomer.

Polymerization rate [%] = {(total charge amount [g] x solid content concentration [mass%] / 100)-(evaporation residue [g])} / monomer charge amount [g] x 100 ... ( II)

[Example 2]
In a polymerization can with an internal volume of 3 liters equipped with a heating / cooling jacket and a stirrer, 15 parts by mass of chloroprene monomer, 35 parts by mass of acrylonitrile monomer, 200 parts by mass of pure water, potassium disproportionate (Harima Kasei Co., Ltd.) (Manufactured) 5.0 parts by mass, potassium hydroxide 0.4 parts by mass, and sodium salt of β-naphthalene sulfonate formalin condensate (manufactured by Kao Co., Ltd.) 1.0 part by mass were added. 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out at a polymerization temperature of 40 ° C. under a nitrogen stream. The addition of chloroprene monomers has specific densities of 0.981, 0.987, 0.992, 0.997, 1.002, 1.007, 1.012, 1.017, 1.022, 1.027. When 1.032 and 1.037 were reached, 5.0 parts by mass of each were added 12 times in total. When the polymerization rate with respect to the total amount of chloroprene and acrylonitrile reached 77%, a water emulsified solution (polymerization terminator solution) of an organic solvent solution containing an antioxidant was added to terminate the polymerization. The water emulsified solution (polymerization terminator) of the organic solvent solution contains 0.1 parts by mass of thiodiphenylamine, which is a polymerization terminator, 0.1 parts by mass of diethylhydroxylamine, and 4,4'-bis (α,) which is an antioxidant. 4.8 parts by mass of α-dimethylbenzyl) diphenylamine was completely dissolved in 9.6 parts by mass of chloroprene, which is an organic solvent, and 0.2 parts by mass of sodium lauryl sulfate, which is a surfactant, and β-naphthalene sulfonate formarin condensate. It was prepared by emulsification using 0.2 parts by mass of sodium salt and 4.0 parts by mass of pure water.
Next, the unreacted monomer and the organic solvent were removed and concentrated by vacuum distillation to adjust the solid content of the polymer latex to 50% by mass.

During the polymerization, the polymerization solution was sampled 10 times or more periodically to measure the unreacted chloroprene monomer and acrylonitrile monomer contained in the polymerization solution. The mass ratio of acrylonitrile monomer to total body was always within ± 10% of the target value.

[Examples 3 to 5]
A chloroprene-acrylonitrile statistical copolymer latex was obtained in the same manner as in Example 1 except that the formulations were changed to the respective formulations shown in Table 1 below. During the polymerization, the polymerization solution was sampled 10 times or more periodically to measure the unreacted chloroprene monomer and acrylonitrile monomer contained in the polymerization solution. The mass ratio of acrylonitrile monomer to total body was always within ± 10% of the target value.

[Example 6]
20 parts by mass of chloroprene monomer, 20 parts by mass of acrylonitrile monomer, 150 parts by mass of pure water, potassium disproportionate (Harima Kasei Co., Ltd.) in a polymerization can with an internal volume of 3 liters equipped with a heating / cooling jacket and a stirrer. ) 5.0 parts by mass, 0.4 parts by mass of potassium hydroxide, and 1.0 part by mass of a sodium salt of β-naphthalene sulfonate formalin condensate (manufactured by Kao Co., Ltd.) were added. 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out at a polymerization temperature of 40 ° C. under a nitrogen stream. The chloroprene monomer is divided into specific densities of 0.989, 0.993, 1.000, 1.007, 1.013, 1.020, 1.026, 1.032, 1.038 and 1.042. , 1.046 and 1.050, 5 parts by mass each, 12 times in total. When the polymerization rate with respect to the total amount of chloroprene and acrylonitrile reached 82%, a water emulsified solution of an organic solvent solution was added to terminate the polymerization. In the water emulsified solution of the organic solvent solution, 0.1 part by mass of thiodiphenylamine and 0.1 part by mass of diethylhydroxylamine, which are polymerization terminators, are completely dissolved in 0.8 part by mass of chloroprene, which is an organic solvent, and a surfactant is used. It was prepared by emulsification using 0.01 part by mass of sodium lauryl sulfate, 0.01 part by mass of sodium salt of β-naphthalene sulfonic acid formalin condensate, and 0.4 part by mass of pure water.
Next, the unreacted monomer and the like and the organic solvent were removed and concentrated by vacuum distillation to adjust the solid content of the polymer latex to 50% by mass, and then 4,4'-bis (α, α), which is an antioxidant, was used. -Dimethylbenzyl) 4.8 parts by mass of diphenylamine is completely dissolved in 9.6 parts by mass of chloroprene, which is an organic solvent, 0.2 parts by mass of sodium lauryl sulfate, which is a surfactant, and sodium, which is a condensate of β-naphthalene sulfonate formalin. An emulsified solution of an organic solvent solution containing an antioxidant, which was emulsified with 0.2 parts by mass of salt and 4.0 parts by mass of pure water, was added. During the polymerization, the polymerization solution was sampled 10 times or more periodically to measure the unreacted chloroprene monomer and acrylonitrile monomer contained in the polymerization solution. The mass ratio of acrylonitrile monomer to total body was always within ± 10% of the target value.

[Example 7]
In a polymerization can with an internal volume of 3 liters equipped with a heating / cooling jacket and a stirrer, 100 parts by mass of chloroprene monomer, 150 parts by mass of pure water, 5.0 parts by mass of disproportionated potassium rosinate (manufactured by Harima Kasei Co., Ltd.), 0.4 parts by mass of potassium hydroxide and 1.0 part by mass of a sodium salt (manufactured by Kao Co., Ltd.) of β-naphthalene sulfonic acid formarin condensate were added. 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out at a polymerization temperature of 40 ° C. under a nitrogen stream. When the polymerization rate with respect to chloroprene reached 82%, a water emulsified solution (polymerization terminator solution) of an organic solvent solution containing an antiaging agent was added to terminate the polymerization. The water emulsified solution (polymerization terminator) of the organic solvent solution contains 0.1 parts by mass of thiodiphenylamine, which is a polymerization terminator, 0.1 parts by mass of diethylhydroxylamine, and 4,4'-bis (α,) which is an antioxidant. 4.8 parts by mass of α-dimethylbenzyl) diphenylamine was completely dissolved in 9.6 parts by mass of chloroprene, which is an organic solvent, and 0.2 parts by mass of sodium lauryl sulfate, which is a surfactant, and β-naphthalene sulfonate formarin condensate. It was prepared by emulsification using 0.2 parts by mass of sodium salt and 4.0 parts by mass of pure water.
Next, the unreacted monomer and the organic solvent were removed and concentrated by vacuum distillation to adjust the solid content of the polymer latex to 50% by mass.

[Comparative Example 1]
A chloroprene homopolymer latex was obtained in the same manner as in Example 7 except that the formulation was changed to the formulation shown in Table 2 below.

[Comparative Example 2]
A chloroprene-acrylonitrile statistical copolymer latex was obtained in the same manner as in Example 1 except that the formulation was changed to the formulation shown in Table 2 below.

[Comparative Example 3]
20 parts by mass of chloroprene monomer, 20 parts by mass of acrylonitrile monomer, 150 parts by mass of pure water, potassium disproportionate (Harima Kasei Co., Ltd.) in a polymerization can with an internal volume of 3 liters equipped with a heating / cooling jacket and a stirrer. (Manufactured) 5.0 parts by mass, potassium hydroxide 0.4 parts by mass, and sodium salt of β-naphthalene sulfonate formalin condensate (manufactured by Kao Co., Ltd.) 1.0 part by mass were added. 0.1 part by mass of potassium persulfate was added as a polymerization initiator, and emulsion polymerization was carried out at a polymerization temperature of 40 ° C. under a nitrogen stream. The chloroprene monomer is divided into specific densities of 0.989, 0.993, 1.000, 1.007, 1.013, 1.020, 1.026, 1.032, 1.038 and 1.042. , 1.046 and 1.050, 5 parts by mass each, 12 times in total. When the polymerization rate with respect to the total amount of chloroprene and acrylonitrile reached 81%, a water emulsified solution of an organic solvent solution was added to terminate the polymerization. In the water emulsified solution of the organic solvent solution, 0.1 part by mass of thiodiphenylamine and 0.1 part by mass of diethylhydroxylamine, which are polymerization terminators, are completely dissolved in 0.8 part by mass of chloroprene, which is an organic solvent, and a surfactant is used. It was prepared by emulsification using 0.01 part by mass of sodium lauryl sulfate, 0.01 part by mass of sodium salt of β-naphthalene sulfonic acid formalin condensate, and 0.4 part by mass of pure water.
Next, unreacted monomers and organic solvents were removed and concentrated by vacuum distillation to adjust the solid content of the polymer latex to 50% by mass, and then 4,4'-bis (α, α-dimethylbenzyl) diphenylamine. 4.8 parts by mass of sodium lauryl sulfate, 0.1 part by mass of sodium salt of β-naphthalene sulfonic acid formalin condensate and 11.2 parts by mass of pure water were used to disperse an antiaging agent. An aqueous dispersion was added.
During the polymerization, the polymerization solution was periodically sampled 10 times or more to measure the unreacted chloroprene monomer and acrylonitrile monomer contained in the polymerization solution. However, the chloroprene monomer and acrylonitrile monomer were measured. The mass ratio of the acrylonitrile monomer to the total weight was always within ± 10% of the target value.

[Comparative Examples 4 and 5]
A chloroprene-acrylonitrile statistical copolymer latex was obtained by the same method as in Example 1 according to the formulation shown in Table 2 below, and an aqueous dispersion of an antiaging agent was further added by the same method as in Comparative Example 3. It was.

<Measurement of unsaturated nitrile (acrylonitrile) content>
It was determined from the content of nitrogen atoms measured by an elemental analyzer (Sumigraph 220F: manufactured by Sumika Chemical Analysis Service, Inc.) using 100 mg of the polymer obtained by freeze-drying the polymer latex produced above. At this time, minute errors due to nitrogen atoms in the polymerization inhibitor and the antiaging agent were ignored. The electric furnace temperature was set to 900 ° C. for the reaction furnace, 600 ° C. for the reduction furnace, 70 ° C. for the column temperature, and 100 ° C. for the detector temperature, and 0.2 ml / min of oxygen was flowed as the combustion gas and 80 ml / min of helium was flowed as the carrier gas. .. The calibration curve was prepared using aspartic acid (10.52%) having a known nitrogen content as a standard substance.

<Measurement of toluene insoluble>
0.75 g of the solid polymer obtained by freeze-drying the polymer latex produced above is cut into 2 mm squares, placed in a conical beaker together with 123 g of toluene, and stirred with a magnetic stirrer at about 1 time / sec. It was dissolved at room temperature of 23 ° C. for 16 hours. Then, the gel content was separated using a 200 mesh wire mesh and dried at 110 ° C. for 60 minutes, and the weight was measured to calculate the toluene insoluble content.

<Measurement of chloroprene monomer amount>
Approximately 0.02 g of the polymer latex produced above was placed in a glass vial, sealed, heated in a headspace sampler, and the gas phase portion was injected into a gas chromatograph for measurement.
(Measurement conditions for gas chromatograph)
The gas chromatograph was performed under the following measurement conditions.
・ Equipment: GC-1700 (manufactured by Shimadzu Corporation)
TurboMatrix HS-40 (manufactured by PerkinElmer)
-Column used: Pora Plot-U 0.53 mmφ x 25 m (film thickness 20 μm)
Gas chromatograph ・ Vaporization chamber temperature: 180 ℃
-Column initial temperature: 130 ° C
・ Final temperature: 190 ℃
-Column temperature rise rate: 2.0 ° C / min
・ Detector: FID
・ Detector temperature: 190 ℃
Headspace sampler ・ Injection time: 0.04min
・ Oven temperature: 80 ℃
・ Needle temperature: 120 ° C
・ Transfer temperature: 150 ℃
・ Heat retention time: 30min
・ Pressurization time: 3.0 min
・ Injection amount: Total amount injection

<Measurement of anti-aging agent content in polymer latex>
Approximately 1 g of the polymer latex produced above was weighed, placed in a 25 mL volumetric flask, and then measured with a tetrahydrofuran solution, and then measured by the following gas chromatograph method.

<Ratio of anti-aging agent concentration in liquid level sampling liquid and bottom surface sampling liquid>
Approximately 40 g of the polymer latex produced above was placed in a 50 ml tube (stainless steel, diameter 35 mm, length 100 mm) for centrifugation in a centrifuge (H-200NR: manufactured by Kokusan Co., Ltd.) at 14,000 rpm for 20 minutes. Centrifugation treatment was performed at 15 ° C., and 2 g of a latex solution was carefully sampled from the liquid level surface of the tube after centrifugation as a liquid level sampling liquid with a syringe. Further, as a bottom surface sampling solution, 2 g of a latex solution was carefully collected from the bottom surface of the tube after centrifugation with a syringe. About 1 g of this liquid level sampling solution and the bottom surface sampling solution were weighed, placed in a 25 mL volumetric flask, and then messed up with a tetrahydrofuran solution, and then measured by the following gas chromatograph method.

(Measurement conditions for gas chromatography)
The gas chromatograph was performed under the following measurement conditions.
・ Equipment: GC-2025 (manufactured by Shimadzu Corporation)
-Column used: DB-5 0.25 mmφ x 30 m (film thickness 1 μm)
-Column temperature: 325 ° C constant-Inlet temperature: 325 ° C
-Detector temperature: 325 ° C
-Column flow rate: He 1 mL / min (Split 1:50)
・ Injection volume: 1 μL (using autosampler)

<Production of film>
The polymer latex was poured into a horizontal stainless steel vat while filtering so that the thickness after drying was about 1.1 mm, and dried at room temperature for 3 days. Then, it was produced by heating and pressing at 140 ° C. for 15 minutes so that the thickness became about 1.0 mm.

<Making RFL film>
After mixing 11 g of resorcin (manufactured by Wako Pure Chemical Industries, Ltd.), 16 g of formaldehyde 37 mass% aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.), 3.0 g of 10% NaOH aqueous solution, and 250 g of pure water, and allowing to stand at room temperature for 20 hours, there. A mixed solution of 100 g of pure water, 200 g of polymerized latex, and 5.0 g of a 10% NaOH aqueous solution was added thereto, and the mixture was further allowed to stand at room temperature for 24 hours. This was prepared by pouring this into a horizontal glass plate so that the thickness after drying was about 0.2 mm, and drying at room temperature for 3 days.

<Heat resistance evaluation>
With respect to the film and RFL film produced above, the breaking strength and breaking elongation after heat treatment at 140 ° C. for 24 hours were measured according to JIS K6251.

<Oil resistance evaluation>
With respect to the film and RFL film produced above, the volume change rate (ΔV) and the weight change rate (ΔW) after being immersed in engine oil (10W-30) at 140 ° C. for 72 hours were measured according to JIS K6258.

<Result>
The results of Examples 1 to 7 are shown in Table 1 below, and the results of Comparative Examples 1 to 5 are shown in Table 2 below.

<Discussion>
Compared with Comparative Example 1 in which the chloroprene polymer latex containing no anti-aging agent was used, Example 7 in which the chloroprene polymer latex containing the anti-aging agent was used had better heat resistance (particularly, elongation at break). I was able to confirm that there was. Further, compared to Comparative Example 2 in which the chloroprene-acrylonitrile statistical copolymer latex containing no anti-aging agent was used, Example 1 in which the chloroprene-acrylonitrile statistical copolymer latex containing an anti-aging agent was used was better. It was confirmed that the heat resistance (particularly, elongation at break) was good.

In Comparative Examples 3 to 5 using the chloroprene-acrylonitrile statistical copolymer latex to which the anti-aging agent was added as an aqueous dispersion, the ratio of the anti-aging agent concentration after centrifugation (liquid level sampling solution / bottom surface sampling solution) was , Less than 0.6. This means that the anti-aging agent is precipitated. On the other hand, in Example 6 using the chloroprene-acrylonitrile statistical copolymer latex to which the anti-aging agent was added as the water emulsion of the organic solvent solution, the ratio of the anti-aging agent concentration after centrifugation (liquid level sampling). Liquid / bottom sampling liquid) was in the range of 0.6 to 1.2. This means that the anti-aging agent is evenly dispersed in the latex. Then, it was confirmed that the heat resistance (particularly, elongation at break) of Example 6 was better than that of Comparative Examples 3 to 5.

Comparing the examples, the case of Example 1 using the unsaturated nitrile-containing chloroprene-acrylonitrile statistical copolymer latex is compared with the case of Example 7 using the unsaturated nitrile-free chloroprene polymer latex. However, it was confirmed that the oil resistance was good. From this result, it was found that the oil resistance was further improved by using the unsaturated nitrile. The fact that the oil resistance of the films of Examples 1 and 2 had a negative volume change rate (ΔV) and weight change rate (ΔW) means that the surfactant in the film was extracted. It is thought that it is.

Furthermore, it was confirmed that Example 1 using an aromatic secondary amine-based anti-aging agent had better heat resistance and elongation at break than Example 5 using a bisphenol-based anti-aging agent. did it. From this result, it was found that the heat resistance was further improved by using the aromatic secondary amine-based antiaging agent.

Even when an emulsion obtained by mixing an organic solvent solution containing an antioxidant, a polymerization inhibitor and an aqueous surfactant solution is added at the time of stopping the polymerization, water containing the antioxidant is further added after the polymerization step. In Comparative Examples 4 and 5 to which the dispersion was added, precipitation of the antioxidant was observed as described above. From this result, when the step of adding the aqueous dispersion containing the anti-aging agent is performed, the dispersion stability of the anti-aging agent is lowered, and as a result, the heat resistance when the chloroprene polymer latex is dried is lowered. I found out.

Claims (15)

A statistical copolymer latex containing an unsaturated nitrile monomer unit and an unsaturated nitrile monomer unit having an unsaturated nitrile monomer unit content of 5 to 20% by mass.
The statistical copolymer latex was diluted with a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0% by mass with respect to 100% by mass of the statistical copolymer latex. The ratio of the antiaging agent concentration in the liquid level sampling solution and the bottom surface sampling solution after centrifuging the statistical copolymer latex at 14000 rpm for 20 minutes (liquid level sampling solution / bottom surface sampling solution). Statistical copolymer latex with a value of 0.6 to 1.2. The first aspect of claim 1, wherein the polymer obtained by drying the statistical copolymer latex at room temperature has a breaking elongation of 500% or more after heat treatment at 140 ° C. for 24 hours measured in accordance with JIS K6251. Statistical copolymer latex. JIS K6251 is an RFL film obtained by drying an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the statistical copolymer latex at room temperature. The statistical copolymer latex according to claim 1 or 2, wherein the elongation at break after heat treatment at 140 ° C. for 24 hours measured in accordance with the above is 150% or more. The statistical copolymer latex according to any one of claims 1 to 3, wherein the anti-aging agent is an aromatic secondary amine-based anti-aging agent. The statistical copolymer latex according to any one of claims 1 to 4, wherein the content of the volatile organic solvent is 200 ppm or less. The polymer obtained by drying the statistical copolymer latex at room temperature was measured according to JIS K6258, and the volume change rate (ΔV) and weight change rate (ΔW) after immersion in engine oil at 140 ° C. for 72 hours. The statistical copolymer latex according to any one of claims 1 to 5, wherein the value of) is in the range of −10 to + 10%. JIS K6258 is an RFL film obtained by drying an RFL adhesive of resorcin (R) / formalin (F) / latex (L) = 10/5/85 (mass ratio) using the statistical copolymer latex at room temperature. 1 to 6 in which the values of the volume change rate (ΔV) and the weight change rate (ΔW) after being immersed in the engine oil at 140 ° C. for 72 hours measured in accordance with the above are in the range of −10 to + 10%. The statistical copolymer latex according to any one of the above. The statistical copolymer latex according to any one of claims 1 to 6, which is used for an RFL adhesive, a dipping product, an adhesive, or a film. An RFL adhesive, a dipping product, an adhesive, or a film using the statistical copolymer latex according to any one of claims 1 to 7. A polymerization step in which emulsion polymerization is carried out using at least a chloroprene monomer unit, and
An anti-aging agent addition step of adding a water emulsified solution of an organic solvent solution containing an anti-aging agent, and
It is a method for producing a polymer latex containing
The anti-aging agent is substantially added by a hydroemulsified solution.
The polymer latex was diluted in a tetrahydrofuran solution, and the content of the antioxidant measured by gas chromatography was 1.0 to 6.0% by mass with respect to 100% by mass of the polymer latex, and the polymer. The ratio of the antiaging agent concentration in the liquid level sampling solution and the bottom surface sampling solution (liquid level sampling solution / bottom surface sampling solution) after centrifugation of the latex at 14,000 rpm for 20 minutes is 0.6 to 1.2. , A method for producing polymer latex. The method for producing a polymer latex according to claim 10, wherein a water emulsified solution obtained by mixing an organic solvent solution containing an antioxidant, a polymerization inhibitor, and an aqueous surfactant solution is added when the emulsion polymerization reaction is stopped. The method for producing a polymer latex according to claim 10 or 11, further comprising an organic solvent removing step of removing the organic solvent after the antiaging agent adding step. The method for producing a polymer latex according to any one of claims 10 to 12, wherein in the polymerization step, emulsion polymerization is carried out using a chloroprene monomer unit and an unsaturated nitrile monomer unit. The method for producing a polymer latex according to claim 13, wherein in the polymerization step, a chloroprene monomer is continuously added or intermittently added 10 times or more after the start of the polymerization reaction. A polymerization step in which emulsion polymerization is carried out using a chloroprene monomer unit and an unsaturated nitrile monomer unit, and a step in which the chloroprene monomer is continuously added or intermittently added 10 times or more after the start of the polymerization reaction.
When the polymerization reaction is stopped, a step of adding a water emulsified solution in which an organic solvent solution containing an aromatic secondary amine-based antiaging agent, a polymerization inhibitor, and an aqueous surfactant solution is added.
Including the step of removing the organic solvent.
The anti-aging agent is obtained substantially by a method of being added by a hydroemulsified solution.
Statistical copolymer latex having an unsaturated nitrile monomer unit content of 5 to 20% by mass.