JP7304753B2 - Adhesive copolymer latex and adhesive composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a copolymer latex for adhesives, more specifically to a copolymer latex for adhesives that bonds rubber and fibers, and an adhesive composition containing the copolymer latex for adhesives.

Copolymer latexes for adhesives containing 50 to 90% by mass of copolymer latex (A) and 10 to 50% by mass of copolymer latex (B) are conventionally known.

Copolymer latex (A) is a monomer composition ( It is obtained by emulsion polymerization of a). Copolymer latex (B) contains 3 to 25% by mass of butadiene monomer, 0 to 5% by mass of vinylpyridine monomer, 55 to 97% by mass of styrene monomer, and 0 ethylenically unsaturated carboxylic acid. 10% by mass and 0 to 20% by mass of another copolymerizable monomer is obtained by emulsion polymerization of the monomer composition (b) (see, for example, Patent Document 1 below).

International Publication No. 2011/102003

However, with the adhesive copolymer latex described in Patent Document 1, it is difficult to achieve both adhesive strength and flexibility of the tire cord.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a copolymer latex for adhesives and an adhesive composition that can achieve both adhesive strength and flexibility of tire cords.

The present invention [1] comprises a butadiene monomer of 35% by mass or more and 75% by mass or less, a vinylpyridine monomer of 10% by mass or more and 30% by mass or less, and a styrene monomer of 10% by mass or more and 55% by mass or less. A copolymer latex (A) that is an emulsion polymer of the monomer composition (a) containing It contains a copolymer latex (B) that is an emulsion polymer, and the copolymer latex ( B) has a solid content of 5% by mass or more and 15% by mass or less, and the number-based average particle size of the latex particles in the copolymer latex (B) is 150 nm or more. Contains polymer latex.

In the present invention [2], the monomer composition (b) further contains 50% by mass or more and 85% by mass or less of the styrene monomer and 30% by mass or less of the vinylpyridine monomer. The adhesive copolymer latex of [1] above is included.

The present invention [3] includes the copolymer latex for adhesives of the above [1] or [2], wherein the monomer composition (a) contains 50% by mass or more of the butadiene monomer. .

The present invention [4] is the above-mentioned [1 ] to [3] any one copolymer latex for adhesives.

The present invention [5] comprises a butadiene monomer of 35% by mass or more and 75% by mass or less, a vinylpyridine monomer of 10% by mass or more and 30% by mass or less, and a styrene monomer of 10% by mass or more and 55% by mass or less. A copolymer latex (A) that is an emulsion polymer of the monomer composition (a) containing Copolymer latex (B), which is an emulsion polymer, and resorcin-formalin resin, relative to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) The solid content of the copolymer latex (B) is 5% by mass or more and 15% by mass or less, and the number-based average particle size of the latex particles in the copolymer latex (B) is 150 nm or more. , including an adhesive composition.

According to the adhesive copolymer latex and the adhesive composition of the present invention, it is possible to achieve both adhesive strength and flexibility of the tire cord.

1. Adhesive Copolymer Latex The adhesive copolymer latex contains a copolymer latex (A) and a copolymer latex (B). The adhesive copolymer latex preferably consists of a copolymer latex (A) and a copolymer latex (B).

(1) Copolymer latex (A)
Copolymer latex (A) is an emulsion polymer of monomer composition (a). Monomer composition (a) contains butadiene monomer, vinylpyridine monomer, and styrene monomer. In other words, the latex particles in the copolymer latex (A) have a structural unit derived from a butadiene monomer, a structural unit derived from a vinylpyridine monomer, and a structural unit derived from a styrene monomer. have.

Examples of butadiene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene and the like. The butadiene monomer is preferably 1,3-butadiene. Monomer composition (a) may comprise one type of butadiene monomer. The monomer composition (a) may contain multiple kinds of butadiene monomers.

Examples of vinylpyridine monomers include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine and 2-methyl-5-vinylpyridine. The vinylpyridine monomer is preferably 2-vinylpyridine. Monomer composition (a) may contain one vinylpyridine monomer. The monomer composition (a) may contain multiple types of vinylpyridine monomers.

Examples of styrene monomers include styrene, α-methylstyrene, monochlorostyrene and the like. The styrene monomer is preferably styrene. Monomer composition (a) may contain one type of styrene monomer. The monomer composition (a) may contain multiple types of styrene monomers.

The monomer composition (a) contains butadiene monomer in an amount of 35% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more and 75% by mass or less, preferably 70% by mass or less. contains. In other words, the latex particles in the copolymer latex (A) contain structural units derived from a butadiene monomer in an amount of 35% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, and 75% by mass. % by mass or less, preferably 70% by mass or less.

When the proportion of the butadiene monomer in the monomer composition (a) is 35% by mass or more and 75% by mass or less, both adhesive strength and flexibility of the tire cord can be achieved.

Here, the adhesive force is the adhesive force between the rubber and the tire cord treated with the adhesive composition containing the adhesive copolymer latex. The adhesive composition will be explained later. Adhesive strength is initial adhesive strength and heat resistant adhesive strength. Initial adhesion and heat resistance adhesion are measured by ASTM D2138-67 (H PULL Test).

The tire cord flexibility is the flexibility of the tire cord treated with the adhesive composition containing the adhesive copolymer latex.

When the ratio of the butadiene monomer in the monomer composition (a) is 50% by mass or more and 75% by mass or less, the flexibility of the tire cord can be improved. When the proportion of the butadiene monomer in the monomer composition (a) is less than 35% by mass, the initial adhesive strength is lowered and the flexibility of the tire cord is lowered. When the proportion of the butadiene monomer in the monomer composition (a) exceeds 75% by mass, the heat-resistant adhesive strength is lowered.

Further, the monomer composition (a) contains 10% by mass or more, preferably 15% by mass or more and 30% by mass or less, preferably 25% by mass or less of a vinylpyridine monomer. In other words, the latex particles in the copolymer latex (A) contain 10% by mass or more, preferably 15% by mass or more and 30% by mass or less, preferably 25% by mass of structural units derived from a vinylpyridine monomer. % by mass or less.

When the monomer composition (a) contains 10% by mass or more and 30% by mass or less of the vinylpyridine monomer, it is possible to achieve both adhesive strength and flexibility of the tire cord. On the other hand, when the proportion of the vinylpyridine monomer in the monomer composition (a) is less than 10% by mass, the initial adhesive strength is lowered. When the proportion of the vinylpyridine monomer in the monomer composition (a) exceeds 30% by mass, the initial adhesive strength and heat-resistant adhesive strength are lowered, and the flexibility of the tire cord is lowered.

Further, the monomer composition (a) contains 10% by mass or more and 55% by mass or less, preferably 50% by mass or less, more preferably 30% by mass or less of a styrene monomer. In other words, the latex particles in the copolymer latex (A) contain a structural unit derived from a styrene monomer, for example, 10% by mass or more and 55% by mass or less, preferably 50% by mass or less, more preferably , 30% by mass or less.

When the ratio of the styrene monomer in the monomer composition (a) is 10% by mass or more and 55% by mass or less, both adhesive strength and flexibility of the tire cord can be achieved. Furthermore, when the ratio of the styrene monomer in the monomer composition (a) is 10% by mass or more and 30% by mass or less, the flexibility of the tire cord can be improved. On the other hand, when the proportion of the styrene monomer in the monomer composition (a) is less than 10% by mass, the heat-resistant adhesive strength is lowered.

The monomer composition (a) may contain other monomers copolymerizable with butadiene monomers, vinylpyridine monomers and styrene monomers.

Other monomers include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid. Ethylenically unsaturated carboxylic acid alkyl ester monomers such as methyl methacrylate, ethyl acrylate and butyl acrylate, for example ethylenically unsaturated carboxylic acid hydroxyalkyl esters such as β-hydroxyethyl acrylate and β-hydroxyethyl methacrylate Examples of monomers include amide monomers such as acrylamide and methacrylamide. Monomer composition (a) may contain one other monomer. The monomer composition (a) may contain multiple types of other monomers.

Monomer composition (a) preferably consists of butadiene monomer, vinylpyridine monomer and styrene monomer.

The number-based average particle size of the latex particles in the copolymer latex (A) is, for example, 50 nm or more, preferably 90 nm or more, and for example, 200 nm or less, preferably 150 nm or less.

The average particle size is obtained by dyeing the copolymer latex with osmium tetroxide, taking a transmission electron microscope photograph, and using an image analysis processing device (device name: IP-1000PC manufactured by Asahi Kasei Co., Ltd.) for 1000 particles. measured by measuring the diameter of the

(2) Copolymer latex (B)
Copolymer latex (B) is an emulsion polymer of monomer composition (b). The monomer composition (b) contains a butadiene monomer, a styrene monomer, and optionally a vinylpyridine monomer. In other words, the latex particles in the copolymer latex (B) have a structural unit derived from a butadiene monomer, a structural unit derived from a styrene monomer, and, if necessary, a structure derived from a vinylpyridine monomer. with units. The monomer composition (b) may also contain other monomers copolymerizable with butadiene monomers, vinylpyridine monomers and styrene monomers. Preferably, the monomer composition (b) consists of butadiene monomer, styrene monomer and vinylpyridine monomer.

The butadiene monomer, styrene monomer, vinylpyridine monomer, and other monomers include the same monomers as those listed in copolymer latex (A), respectively.

The monomer composition (b) contains 3% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more and 30% by mass or less of butadiene monomer. In other words, the latex particles of the copolymer latex (B) contain structural units derived from a butadiene monomer in an amount of 3% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, and 30% by mass. % or less.

When the proportion of the butadiene monomer in the monomer composition (b) is 3% by mass or more and 30% by mass or less, both adhesive strength and flexibility of the tire cord can be achieved. On the other hand, when the proportion of the butadiene monomer in the monomer composition (b) is less than 3% by mass, the initial adhesive strength is lowered. When the proportion of the butadiene monomer in the monomer composition (b) exceeds 30% by mass, the heat-resistant adhesive strength is lowered.

Further, the monomer composition (b) contains, for example, 50% by mass or more, preferably 55% by mass or more, and for example, 85% by mass or less, preferably 82% by mass or less of a styrene monomer. In other words, the latex particles of the copolymer latex (B) contain a structural unit derived from a styrene monomer, for example, 50% by mass or more, preferably 55% by mass or more, for example, 85% by mass or less, preferably , 82% by mass or less.

When the ratio of the styrene monomer in the monomer composition (b) is 50% by mass or more and 85% by mass or less (that is, 50 to 85% by mass), both adhesive strength and flexibility of the tire cord are achieved. can be achieved.

Further, when the monomer composition (b) contains a vinylpyridine monomer, the vinylpyridine monomer is, for example, 30% by mass or less, preferably 15% by mass or less, for example, 3% by mass or more. contains. In other words, the latex particles of the copolymer latex (B) contain, for example, 30% by mass or less, preferably 15% by mass or less, for example 3% by mass or more, of structural units derived from a vinylpyridine monomer. .

When the proportion of the vinylpyridine monomer in the monomer composition (b) is 30% by mass or less, both adhesive strength and flexibility of the tire cord can be achieved.

The number-based average particle size of the latex particles in the copolymer latex (B) is different from the number-based average particle size of the latex particles in the copolymer latex (A). The number-based average particle size of the latex particles in the copolymer latex (B) is larger than the number-based average particle size of the latex particles in the copolymer latex (A). The number-based average particle size of the latex particles in the copolymer latex (B) is 150 nm or more, for example, 250 nm or less, preferably 200 nm or less, more preferably 180 nm or less.

When the number-based average particle size of the latex particles in the copolymer latex (B) is 150 nm or more, both adhesive strength and flexibility of the tire cord can be achieved. On the other hand, when the number-based average particle size of the latex particles in the copolymer latex (B) is less than 150 nm, the adhesive strength (initial adhesive strength and heat-resistant adhesive strength) decreases.

(3) Blending ratio of copolymer latex (A) and copolymer latex (B) The ratio of the solid content of the copolymer latex (A) to the total amount of the solid content of the copolymer latex (A) is 85% by mass or more, preferably 88% by mass or more and 95% by mass or less, preferably 92% by mass or less.

In the adhesive copolymer latex, the ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is 5. % by mass or more, preferably 8% by mass or more and 15% by mass or less, preferably 12% by mass or less.

When the ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is 5% by mass or more and 15% by mass or less, It is possible to achieve both adhesive strength and flexibility of the tire cord. Furthermore, the ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is 10% by mass or more and 15% by mass or less. And the flexibility of the tire cord can be improved. On the other hand, when the ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is less than 5% by mass, heat-resistant adhesion power is reduced. When the ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) exceeds 15% by mass, the flexibility of the tire cord is reduced. decreases.

2. Production of Copolymer Latex for Adhesives (1) Production of Copolymer Latex To produce copolymer latex for adhesives, copolymer latex (A) and copolymer latex (B) are first manufacture.

To obtain the copolymer latex (A), the monomer composition (a) is emulsion polymerized. To obtain the copolymer latex (B), the monomer composition (b) is emulsion polymerized.

For emulsion polymerization of the monomer composition (a) or the monomer composition (b), for example, the monomer composition (a) or the monomer composition (b), water, and if necessary The monomer composition (a) or the monomer composition (b) is emulsified by mixing with an emulsifier.

Examples of emulsifiers include nonionic surfactants such as polyethylene glycol alkyl esters, alkylphenyl ethers, and alkyl ethers, rosinates, fatty acid salts, higher alcohol sulfates, alkylbenzenesulfonates, Anionic surfactants such as alkyldiphenyl ether sulfonates, aliphatic sulfonates, aliphatic carboxylates, sulfate salts of nonionic surfactants, and formalin condensates of naphthalenesulfonates, preferably Examples include anionic surfactants, more preferably formalin condensates of alkylbenzenesulfonates, rosinates and naphthalenesulfonates. One type of emulsifier may be used, or a plurality of types may be used.

The emulsifier may be added to the polymerization system by any method of batch addition, continuous addition, or divided addition, and is added not only at the beginning of the polymerization, but also during or after the polymerization, taking into account the stability during polymerization. be able to.

Next, a polymerization initiator is added to the monomer composition (a) or the emulsion of the monomer composition (b).

The polymerization initiator is a radical polymerization initiator, for example, water-soluble polymerization initiators such as potassium persulfate, sodium persulfate, ammonium persulfate, cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide. , acetyl peroxide, diisopropylbenzene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide. Preferably, water-soluble polymerization initiators include potassium persulfate, sodium persulfate and ammonium persulfate, and oil-soluble polymerization initiators include cumene hydroperoxide.

In addition, in the emulsion polymerization of the monomer composition (a) or the monomer composition (b), if necessary, a reducing agent, a chain transfer agent, a hydrocarbon solvent, and other additives may be added.

Examples of reducing agents include sulfite, hydrogen sulfite, pyrosulfite, nitrite, nitionate, thiosulfate, formaldehyde sulfonate, benzaldehyde sulfonate, L-ascorbic acid, erythorbic acid. , tartaric acid, citric acid and the like and salts thereof, reducing sugars such as dextrose and saccharose, and amines such as dimethylaniline and triethanolamine. Carboxylic acids and salts thereof are preferred, and L-ascorbic acid and erythorbic acid are more preferred.

Examples of chain transfer agents include alkylmercaptans such as n-hexylmercaptan, n-octylmercaptan, t-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan and n-stearylmercaptan, dimethylxanthogen disulfide, diisopropyl xanthogen compounds such as xanthogen disulfide, thiuram compounds such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, such as 2,6-di-t-butyl-4-methylphenol, styrenated phenol, etc. phenolic compounds, for example, allyl compounds such as allyl alcohol, for example, dichloromethane, dibromomethane, halogenated hydrocarbon compounds such as carbon tetrabromide, for example, α-benzyloxystyrene, α-benzyloxyacrylonitrile, α-benzyloxy Vinyl ethers such as acrylamide, for example, triphenylethane, pentaphenylethane, acrolein, methacrolein, thioglycolic acid, thiomalic acid, 2-ethylhexylthioglycolate, α-methylstyrene dimer, etc., preferably alkyl mercaptan. and more preferably n-octylmercaptan and t-dodecylmercaptan. One type of chain transfer agent may be used, or a plurality of types may be used.

The chain transfer agent is added in a proportion of, for example, 10 parts by mass or less, preferably 7 parts by mass or less, for example, 0.05 parts by mass or more, relative to 100 parts by mass of the monomer composition (a). be.

Examples of hydrocarbon solvents include saturated hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane, and cycloheptane, and pentene, hexene, heptene, cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene, and 1-methylcyclohexene. and unsaturated hydrocarbons such as, preferably cyclohexene. Cyclohexene has a low boiling point and can be easily recovered and reused by steam distillation or the like after completion of polymerization, and is suitable from the viewpoint of environmental load.

Other additives include, for example, electrolytes such as sodium hydroxide, sodium carbonate, potassium carbonate and sodium hydrogen carbonate, polymerization inhibitors such as hydroquinone, polymerization accelerators such as chelating agents, and the like.

In the production of copolymer latex (A) or copolymer latex (B), the polymerization method is not limited, and batch polymerization, semi-batch polymerization, seed polymerization and the like can be applied. Also, the method of adding various components is not limited, and a batch addition method, a divided addition method, a continuous addition method, a power feed method, and the like can be applied.

(2) Preparation of Copolymer Latex for Adhesive The copolymer latex for adhesive is prepared by mixing the copolymer latex (A) and the copolymer latex (B) in the above ratio. be. The adhesive copolymer latex may be prepared by diluting a mixture of the copolymer latex (A) and the copolymer latex (B) with water.

3. Adhesive Composition The adhesive copolymer latex is incorporated into the adhesive composition. The adhesive composition is preferably used to bond rubber and rubber reinforcing fibers.

The rubber is not particularly limited, and examples thereof include natural rubber, SBR, NBR, chloroprene rubber, polybutadiene rubber, polyisoprene rubber, and various modified rubbers thereof. In addition, known additives such as fillers, softening agents, vulcanizing agents, and vulcanization accelerators can be blended with the rubber.

Examples of rubber reinforcing fibers include nylon fibers, polyester fibers, and aramid fibers. Moreover, the form of these fibers is not particularly limited, and examples thereof include cords, cables, woven fabrics, canvas, short fibers, and the like.

The adhesive composition contains an adhesive copolymer latex and a resorcin-formalin resin. In other words, the adhesive composition contains copolymer latex (A), copolymer latex (B), and resorcin-formalin resin. The adhesive composition is prepared by mixing an adhesive copolymer latex and a resorcinol-formalin resin. The adhesive composition may be prepared by mixing the copolymer latex (A), copolymer latex (B), and resorcinol-formalin resin.

The proportion of the resorcinol-formalin resin in the adhesive composition is, in terms of solid content, relative to 100 parts by mass of the adhesive copolymer latex, for example, 5 parts by mass or more, for example, 100 parts by mass or less, preferably It is 90 parts by mass or less.

The adhesive composition may optionally contain isocyanate, blocked isocyanate, ethylene urea, 2,6-bis(2,4-dihydroxyphenylmethyl)-4-chlorophenol, condensation of sulfur monochloride and resorcinol. modified resorcinol-formalin resin such as a mixture with a compound and resorcinol-formalin condensate, polyepoxide, modified polyvinyl chloride, adhesion aids such as carbon black, fillers, cross-linking agents, vulcanizing agents, vulcanization accelerators, etc. You may

Then, in order to bond the rubber and the rubber reinforcing fibers, first, the rubber reinforcing fibers are treated with an adhesive composition.

Specifically, the adhesive composition is obtained by dipping rubber reinforcing fibers into the adhesive composition, for example, using a dipping machine or the like. Next, the rubber reinforcing fiber immersed in the adhesive composition is heated at, for example, 100° C. or higher, preferably 110° C. or higher, for example, 150° C. or lower, preferably 130° C. or lower, for example, for 80 seconds or longer. is dried for 100 seconds or more, for example 200 seconds or less, preferably 150 seconds or less. Thereafter, the dried rubber reinforcing fibers are dried at, for example, 180° C. or higher, preferably 200° C. or higher, for example, 300° C. or lower, preferably 260° C. or lower, for example, for 30 seconds or longer, preferably 50 seconds or longer. For example, it is heated (baked) for 100 seconds or less, preferably 80 seconds or less. This completes the treatment of the adhesive composition on the rubber reinforcing fibers.

After the treatment, the adhesive composition-treated rubber reinforcing fibers are brought into contact with the rubber, and the rubber and the rubber reinforcing fibers are bonded by heating and pressurizing the rubber and the rubber reinforcing fibers.

4. Effect The adhesive copolymer latex and adhesive composition described above contain the copolymer latex (A) and the copolymer latex (B). The copolymer latex (A) contains 35% by mass to 75% by mass of butadiene monomer, 10% by mass to 30% by mass of vinylpyridine monomer, and 10% by mass to 55% by mass of styrene monomer. It is an emulsion polymer of the monomer composition (a) containing and. Copolymer latex (B) is an emulsion polymer of monomer composition (b) containing 3% by mass or more and 30% by mass or less of butadiene monomer. The ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is 5% by mass or more and 15% by mass or less. and the number-based average particle size of the copolymer latex (B) is 150 nm or more.

Therefore, it is possible to achieve both adhesive strength and flexibility of the tire cord.

Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited by the following examples. In addition, the specific numerical values of the mixing ratio or content ratio used in the following description are the upper limit or lower limit of the corresponding mixing ratio or content ratio described in the above "Mode for Carrying Out the Invention" value can be substituted.

1. Production of Copolymer Latex (A) (1) Synthesis Examples 1 and 2 and Comparative Synthesis Examples 1-3
An autoclave equipped with a stirrer was charged with 130 parts by mass of water, and 1 part by mass of formalin condensate of sodium naphthalenesulfonate (emulsifier), 0.5 parts by mass of sodium hydroxide (electrolyte) and 4 parts by mass of potassium rosinate (emulsifier) were dissolved. let me

Next, the monomer composition (a) shown in Table 1 and 0.55 parts by mass of t-dodecylmercaptan (chain transfer agent) were added and emulsified.

Thereafter, 0.5 part by mass of potassium persulfate (polymerization initiator) was added to the emulsion, and the internal temperature was kept at 50° C. to polymerize the monomer composition (a).

When the polymerization conversion reaches 93%, 0.1 part by mass of hydroquinone (polymerization inhibitor) is added to terminate the polymerization, and then the unreacted monomer is removed by distillation under reduced pressure. 2 and the copolymer latexes (A) of Comparative Synthesis Examples 1 to 3 were obtained.

Table 1 shows the average particle size of the latex particles in the copolymer latex (A).

(2) Synthesis Example 3
An autoclave equipped with a stirrer was charged with 135 parts by mass of water, and 1 part by mass of formalin condensate of sodium naphthalenesulfonate, 0.5 parts by mass of sodium hydroxide and 5.0 parts by mass of potassium rosinate were dissolved.

Next, the first-stage monomer composition (a) shown in Table 1 and 0.3 parts by mass of t-dodecylmercaptan were added and emulsified.

Thereafter, 0.5 part by mass of potassium persulfate was added to the emulsion, and the internal temperature was kept at 55° C. to polymerize the first-stage monomer composition (a).

When the polymerization conversion rate of the first-stage monomer composition (a) reached 82%, the second-stage monomer composition (a) shown in Table 1 and 0.25 mass of t-dodecylmercaptan were added. parts were continuously added to continue the polymerization.

When the polymerization conversion rate reaches 93%, 0.1 part by mass of hydroquinone (polymerization inhibitor) is added to terminate the polymerization, and then the unreacted monomer is removed by distillation under reduced pressure. A copolymer latex (A) was obtained.

Table 1 shows the average particle size of the latex particles in the copolymer latex (A).

2. Production of copolymer latex (B) An autoclave equipped with a stirrer was charged with the amount of water shown in Table 2, and the amount of emulsifier (specifically, sodium dodecylbenzenesulfonate or sodium rosinate), electrolyte, A polymerization initiator (specifically, potassium persulfate) was added and stirred.

Then, the amount of monomer composition (b) shown in Table 2, a chain transfer agent (specifically, t-dodecylmercaptan), and a hydrocarbon solvent (specifically, cyclohexene) were added, and the internal temperature was was maintained at the temperature shown in Table 2, and the polymerization was terminated when the polymerization conversion rate reached 98%.

Then, after adjusting the pH to 8 by adding an aqueous sodium hydroxide solution, unreacted monomers and the like are removed by steam distillation, and the copolymer latexes (B) of Synthesis Examples 4 to 7 and Comparative Synthesis Examples 4 to 7 are obtained. got

Table 2 shows the average particle size of the latex particles in the copolymer latex (B).

3. Preparation of Adhesive Copolymer Latex Copolymer latex (A) and copolymer latex (B) were blended and mixed in the proportions shown in Tables 3 and 4, and each Example and each Comparative Example A copolymer latex for adhesives was obtained.

4. Preparation of Adhesive Composition After adding 4 parts by mass of 10% sodium hydroxide to 260 parts by mass of water and stirring, 7.9 parts by mass of resorcin and 8.6 parts by mass of 37% formalin were added and mixed by stirring. , and aged at 30° C. for 6 hours to synthesize a resorcin-formalin resin. The solid content (evaporation residue) of the resorcinol-formalin resin was 4.1% by mass.

Next, water was added to 100 parts by mass of the adhesive copolymer latex of each example and each comparative example so that the solid content concentration of the adhesive composition was 16.5% by mass, and the mixture was stirred. - The total amount (280.5 parts by mass) of formalin resin and 11.4 parts by mass of 28% aqueous ammonia were added and mixed with stirring.

The ratio of the resorcinol-formalin resin in the adhesive composition was 11.5 parts by mass in terms of solid content with respect to 100 parts by mass of the adhesive copolymer latex.

Then, 46.3 parts by mass of a 27% blocked isocyanate dispersion (SU-125F manufactured by Meisei Chemical Industry Co., Ltd.) was added and aged at 30° C. for 48 hours to obtain an adhesive composition.

5. Evaluation (1) Preparation of evaluation sample Using a test single cord dipping machine, a pretreated polyester tire cord (1500D/2) was immersed in the adhesive composition of each example and each comparative example. C. for 120 seconds and then baked at 240.degree. C. for 60 seconds.

(2) Measurement of Flexibility of Tire Cord The polyester tire cord treated with the adhesive composition of each example and each comparative example was cut to 11 cm and measured with a handleometer. The slit width of the handleometer was set to 20 mm. The average value of 10 lines was taken as flexibility.

Tables 3 and 4 show the results.

(3) Measurement of Adhesive Strength A polyester tire cord treated with the adhesive composition of each example and each comparative example was sandwiched between rubbers prepared according to the following formulation, and heated at 160° C. for 20 minutes (initial adhesive strength evaluation conditions), or vulcanization pressing was performed at 170° C. for 50 minutes (heat-resistant adhesion evaluation conditions).

<Rubber prescription>
Natural rubber 70 parts by mass SBR rubber 30 parts by mass FEF carbon 40 parts by mass Process oil 4 parts by mass Antigen RD (manufactured by Sumitomo Chemical Co., Ltd.) 2 parts by mass Stearic acid 1.5 parts by mass Zinc oxide 5 parts by mass Dibenzothiazyl disulfide 0.9 parts by mass Sulfur 2.7 parts by mass Antigen RD is a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline.

Initial adhesive strength and heat resistant adhesive strength between rubber and rubber reinforcing fiber were measured according to ASTM D2138-67 (H Pull Test).

Tables 3 and 4 show the results.

Claims (5)

A monomer composition containing 35% by mass or more and 75% by mass or less of a butadiene monomer, 10% by mass or more and 30% by mass or less of a vinylpyridine monomer, and 10% by mass or more and 55% by mass or less of a styrene monomer a copolymer latex (A) which is an emulsion polymer of (a);
and a copolymer latex (B) which is an emulsion polymer of the monomer composition (b) containing 3% by mass or more and 30% by mass or less of the butadiene monomer,
The ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is 5% by mass or more and 15% by mass or less. and
A copolymer latex for an adhesive, wherein the number-based average particle size of the latex particles in the copolymer latex (B) is 150 nm or more. The claim wherein the monomer composition (b) further contains 50% by mass or more and 85% by mass or less of the styrene monomer and 30% by mass or less of the vinylpyridine monomer. 2. Copolymer latex for adhesives according to 1. 3. The adhesive copolymer latex according to claim 1, wherein the monomer composition (a) contains 50% by mass or more of the butadiene monomer. Claims 1 to 3, characterized in that the ratio of the copolymer latex (B) to the total amount of the copolymer latex (A) and the copolymer latex (B) is 10% by mass or more. Item 4. The copolymer latex for adhesives according to any one of items 3. A monomer composition containing 35% by mass or more and 75% by mass or less of a butadiene monomer, 10% by mass or more and 30% by mass or less of a vinylpyridine monomer, and 10% by mass or more and 55% by mass or less of a styrene monomer a copolymer latex (A) which is an emulsion polymer of (a);
a copolymer latex (B) which is an emulsion polymer of the monomer composition (b) containing 3% by mass or more and 30% by mass or less of the butadiene monomer;
resorcinol-formalin resin,
The ratio of the solid content of the copolymer latex (B) to the total amount of the solid content of the copolymer latex (A) and the solid content of the copolymer latex (B) is 5% by mass or more and 15% by mass or less. and
The adhesive composition, wherein the number-based average particle size of the latex particles in the copolymer latex (B) is 150 nm or more.