JP2005075920A - Copolymer latex for adhesive of rubber and fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copolymer latex hardly causing reduction of cord strength after heat treatment, and having good adhesive force between a rubber (especially ethylene-propylene-based rubber) and a fiber. <P>SOLUTION: The copolymer latex for an adhesive of the rubber and the fiber comprises (A) 10-90 pts. wt. copolymer latex obtained by subjecting 90-100 t.% aliphatic conjugated dienic monomer and 0-10 wt.% other monomers copolymerizable therewith (except an ethylenic unsaturated carboxylic acid monomer) to emulsion polymerization, and (B) 10-90 pts. wt. copolymer latex obtained by subjecting 5-50 wt.% aliphatic conjugated dienic monomer, 5-25 wt.% vinylpyridine-based monomer and 25-90 wt.% other monomers copolymerizable therewith to the emulsion polymerization [with the proviso that the total of the components (A) and (B) is 100 pts. wt.]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a copolymer latex for rubber and fiber adhesives. More particularly, the present invention relates to an improved copolymer latex for an adhesive of rubber and fiber suitable for bonding of fiber and rubber contained in rubber products such as tires, belts and hoses.

Conventionally, fibers such as nylon, polyester and aramid are widely used as rubber reinforcing fibers in rubber products such as tires, belts and hoses.
These fibers used for rubber reinforcement themselves have poor adhesion to rubber, and the vinylpyridine-butadiene copolymer latex alone or a mixture thereof with other rubber latex and resorcin-formalin resin (hereinafter referred to as RF range). In general, an adhesive composition (hereinafter referred to as RFL) is used for practical use.
The vinylpyridine-butadiene copolymer latex used in this RFL is a copolymer obtained by emulsion polymerization of 15% by weight of 2-vinylpyridine, 70% by weight of 1,3-butadiene and 15% by weight of styrene. Combined latex is common.

In any of these fibers, when it is intended to obtain a good adhesive strength with rubber, after the fiber is immersed in RFL and dried, the nylon fiber is 170 ° C. or higher, and the polyester fiber or aramid fiber is 220 ° C. or higher. Although it is necessary to heat-treat, there is a problem in this step that the strength of the fiber itself before the treatment is lowered.
In order to minimize the decrease in fiber strength, if the heat treatment is performed at a relatively low temperature, the adhesive strength with the rubber is reduced. Conversely, if the heat treatment is performed at a higher temperature in order to obtain a higher adhesive strength with the rubber. The strength of the fiber decreases. For this reason, there has been a demand for the development of a copolymer latex for an adhesive that can reduce the strength of the fiber after heat treatment and can provide high adhesive strength.

For this reason, the improvement examination about the vinylpyridine-butadiene-type copolymer latex used for RFL is performed, and Japanese Patent Publication No. 1-49308 (patent document 1) and Japanese Patent Publication No. 1-49309 (patent document 2). JP-B-2-24314 (Patent Document 3) and JP-A-11-158289 (Patent Document 4) propose a copolymer latex composed of copolymer particles having a specific monomer composition and structure. ing. However, even when these copolymer latexes are used in RFL, the severe quality demands for adhesive strength and fiber strength in recent years cannot be sufficiently satisfied, and further improvements are desired. These are particularly noticeable when ethylene-propylene rubbers such as EP rubber and EPDM are used as the rubber to be adhered, but these documents do not describe improvement in adhesion to ethylene-propylene rubber.
Japanese Examined Patent Publication No. 1-449308 Japanese Patent Publication No. 1-49309 Japanese Patent Publication No. 2-24314 JP-A-11-158289

The present invention solves the above-mentioned problems, and provides a copolymer latex that has a small decrease in cord strength after heat treatment and has good adhesion between rubber (particularly ethylene-propylene rubber) and fibers. It is the purpose.

The present invention is characterized by using a copolymer latex obtained by mixing two specific types of copolymer latex at a specific ratio.

The adhesive composition using the copolymer latex of the present invention has little decrease in the strength of the cord after heat treatment, and gives a good adhesive force between rubber (especially ethylene-propylene rubber) and fiber.

The present invention includes 90 to 100% by weight of an aliphatic conjugated diene monomer and 0 to 10% by weight of another monomer copolymerizable therewith (excluding an ethylenically unsaturated carboxylic acid monomer). 10 to 90 parts by weight (in terms of solid content) of copolymer latex (A) obtained by emulsion polymerization, 5 to 50% by weight of aliphatic conjugated diene monomer, 5 to 25% by weight of vinylpyridine monomer and It consists of 10 to 90 parts by weight (in terms of solid content) of copolymer latex (B) obtained by emulsion polymerization of 25 to 90% by weight of other monomers copolymerizable with these (however, (A) and ( A total of 100 parts by weight of B) is provided. A copolymer latex for an adhesive of rubber and fiber is provided.

The present invention is described in detail below. In principle, the difference between the copolymer latex (A) and the copolymer latex (B) is clearly indicated, and the common points will be described at the same time.

Examples of the aliphatic conjugated diene monomer used in the copolymer latex (A) or (B) of the present invention include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3- Examples thereof include dimethyl-1,3-butadiene, and these can be used alone or in combination of two or more. 1,3-butadiene is particularly preferable.

When the aliphatic conjugated diene monomer used in the copolymer latex (A) is less than 90% by weight, the initial adhesive strength is lowered.
Further, if the aliphatic conjugated diene monomer used in the copolymer latex (B) is less than 5% by weight, the initial adhesive strength is lowered, and if it exceeds 50% by weight, the cord strength and the heat resistant adhesive strength are lowered. Preferably, it is 5-45 weight%, More preferably, it is 5-35 weight%.

Examples of other copolymerizable monomers (excluding ethylenically unsaturated carboxylic acid monomers) used in the copolymer latex (A) include styrene, α-methylstyrene, and monochlorostyrene. Aromatic vinyl monomers, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, and ethylenically unsaturated carboxylic acid alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl acrylate Monomers, unsaturated monomers containing a hydroxyalkyl group such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, and unsaturated carboxylic acid amide monomers such as acrylamide and methacrylamide. Two or more species can be used. In particular, styrene and acrylonitrile are preferable.

Examples of the vinylpyridine monomer used in the copolymer latex (B) of the present invention include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, and the like. One or more of these can be used. 2-vinylpyridine is particularly preferable.
When the vinylpyridine monomer used in the copolymer latex (B) is less than 5% by weight, both initial adhesive strength and heat resistant adhesive strength are reduced. If it exceeds 25% by weight, the initial adhesive strength is lowered. Preferably it is 5 to 20 weight%, More preferably, it is 7 to 18 weight%.

Other copolymerizable monomers that can be used in the copolymer latex (B) of the present invention include aromatic vinyl monomers such as styrene, α-methylstyrene, and monochlorostyrene, acrylonitrile, and methacrylate. Vinyl cyanide monomers such as nitrile, ethyl (meth) acrylate, ethyl (meth) acrylate, ethylenically unsaturated carboxylic acid alkyl ester monomers such as 2-ethylhexyl acrylate, β-hydroxyethyl acrylate, β -Unsaturated monomer containing hydroxyalkyl group such as hydroxyethyl methacrylate Unsaturated carboxylic acid amide monomer such as acrylamide and methacrylamide and ethylenically unsaturated carboxylic acid such as methacrylic acid, itaconic acid and fumaric acid Body, etc., each one or more It is possible. In particular, styrene and methyl methacrylate are preferable.

Among the monomers used in the copolymer latex (B), if the other copolymerizable monomer is less than 25% by weight, the cord strength and the heat-resistant adhesive strength are lowered, and if it exceeds 90% by weight, initial adhesion is achieved. Both strength and heat-resistant adhesive strength are reduced. Preferably it is 35-90 weight%, More preferably, it is 50-90 weight%.

The ratio of the copolymer latex (A) of the copolymer latex of the present invention to the weight part (in terms of solid content) of the copolymer latex (B) is (A) / (B) = 10 to 90/90 to 10 ( However, the sum of (A) and (B) is 100 parts by weight). Outside this range, the effect of improving the cord strength, initial adhesive strength and heat resistant adhesive strength is small. Preferably it is 20-80 / 20-80, More preferably, it is 30-70 / 30-70.

The copolymer latex of the present invention is produced by a known method. That is, there is no particular limitation on the method for adding the monomer used in the copolymer latex during the polymerization, and any of a batch addition method, a divided addition method, a continuous addition method, and the like can be adopted.

In the polymerization of the copolymer latex used in the present invention, as an emulsifier, rosin acid soap, fatty acid soap, sulfate ester of higher alcohol, alkylbenzene sulfonate, alkyl diphenyl ether sulfonate, aliphatic sulfonate, fat Nonionic surfactants such as aromatic carboxylates, anionic surfactants such as sulfate salts of nonionic surfactants, or the alkyl ester type, alkylphenyl ether type, and alkyl ether type of polyethylene glycol, etc. 1 type, or 2 or more types can be used.

In the emulsion polymerization method of the present invention, conventionally known chain transfer agents, polymerization initiators, electrolytes, polymerization accelerators, chelating agents, and the like, and further hydrocarbon solvents can be used.

Examples of chain transfer agents include n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-stearyl mercaptan, and other alkyl mercaptans, dimethylxanthogen disulfide, diisopropylxanthogen disulfide, etc. Xanthogen compounds, thiuram compounds such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, phenol compounds such as 2,6-di-t-butyl-4-methylphenol, styrenated phenol, allyl alcohol, etc. Allyl compounds, halogenated hydrocarbon compounds such as dichloromethane, dibromomethane, carbon tetrabromide, α-benzyloxystyrene, α-benzyloxya Examples include vinyl ethers such as acrylonitrile and α-benzyloxyacrylamide, triphenylethane, pentaphenylethane, acrolein, methacrolein, thioglycolic acid, thiomalic acid, 2-ethylhexyl thioglycolate, terpinolene, and the like. Two or more types can be used.
These chain transfer agents are usually used at 0 to 10 parts by weight with respect to 100 parts by weight of the monomer.

As the polymerization initiator, water-soluble polymerization initiators such as potassium persulfate, sodium persulfate, and ammonium persulfate, redox polymerization initiators, and oil-soluble polymerization initiators such as benzoyl peroxide can be appropriately used. In particular, the use of a water-soluble polymerization initiator is preferred.

In the polymerization, saturated hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane and cycloheptane, and unsaturated hydrocarbons such as pentene, hexene, heptene, cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene and 1-methylcyclohexene. Hydrocarbon compounds such as aromatic hydrocarbons such as benzene, toluene and xylene may be used.

The mixture of the copolymer latex (A) and the copolymer latex (B) of the present invention is a rubber-fiber adhesive copolymer latex, for example, mixed with a resorcin-formalin resin to bond rubber and fiber. An agent composition is obtained. Usually, it is preferable to use 5 to 100 parts by weight (solid content) of resorcin-formalin resin with respect to 100 parts by weight (solid content) of the mixture of copolymer latex (A) and copolymer latex (B).

Further, this adhesive composition includes isocyanate, blocked isocyanate, ethylene urea, 2,6-bis (2,4-dihydroxyphenylmethyl) -4-chlorophenol, a condensation product of sulfur monochloride and resorcin, and resorcin- Addition of adhesives such as modified resorcin-formalin resin such as mixture with formalin condensate, polyepoxide, modified polyvinyl chloride, carbon black, filler, crosslinking agent, vulcanizing agent, vulcanization accelerator, etc. There is no problem.

Examples of the fibers targeted in the present invention include nylon fibers, polyester fibers, aramid fibers, etc., but are not particularly limited thereto, and these fibers are any of cords, cables, woven fabrics, canvases, short fibers, etc. It may be a form.

In addition, the fibers treated with the adhesive composition and the rubber to be used for adhesion include ethylene-propylene rubber such as EP rubber and EPDM rubber, CSM rubber, natural rubber, SBR, NBR, chloroprene rubber, and polybutadiene rubber. Polyisoprene rubbers and various modified rubbers thereof may be mentioned. In particular, the present invention exhibits a remarkable improvement effect on ethylene-propylene rubbers such as EP rubber and EPDM rubber.

In addition, if necessary, a part of the adhesive composition containing the mixture of the copolymer latex (A) and the copolymer latex (B) of the present invention may be converted into a styrene-butadiene copolymer latex or a carboxy-modified styrene-butadiene. Copolymer latex, acrylonitrile-butadiene copolymer latex, carboxy-modified acrylonitrile-butadiene copolymer latex, chloroprene latex, EPDM latex, CSM latex, isoprene latex, etc. may be substituted, but the amount used is all It is preferable that it is less than 50 weight% among solid content of copolymer latex. More preferably, it is less than 30% by weight.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, all parts and% mean parts by weight and% by weight unless otherwise specified.

Production of copolymer latex (A) In an autoclave equipped with a stirrer, 170 parts of water, 0.1 part of sodium hydroxide and 2.5 parts of sodium rosinate are added and dissolved. Next, the monomers shown in Table 1 and 0.5 part of t-dodecyl mercaptan are charged and emulsified. Next, 0.3 part of potassium persulfate is added, the whole is kept at 70 ° C., and polymerization is carried out. When the polymerization conversion rate reaches 95% of all monomers, the polymerization is stopped. Unreacted monomers were removed from the obtained copolymer latex by distillation under reduced pressure to obtain copolymer latexes A-1 to A-4.

Production of copolymer latex (B) 130 parts of water, 1 part of sodium naphthalenesulfonate / formalin condensate, 0.5 part of sodium hydroxide and 4 parts of potassium rosinate are dissolved in an autoclave equipped with a stirrer. . Next, the monomer shown in Table 1 and 0.4 part of t-dodecyl mercaptan are charged and emulsified. Subsequently, 0.5 part of potassium persulfate is added, the whole is kept at 50 ° C., and polymerization is carried out. When the polymerization conversion rate reaches 95% of all monomers, 0.1 part of hydroquinone is added to stop the polymerization. Unreacted monomers were removed from the obtained copolymer latex by distillation under reduced pressure to obtain copolymer latexes B-1 to B-5.

Application example-1
(Adjustment of RFL solution)
After adding 3 parts of 10% sodium hydroxide to 236 parts of water and stirring, add 11 parts of resorcin and 16.2 parts of 37% formalin, stir and mix, and age at 25 ° C. for 6 hours to prepare an RF resin. . Next, the copolymer latex (A) and the copolymer latex (B) were mixed at a ratio (solid content) shown in Table 2 in 100 parts (solid content) of each of the copolymer latex (solid content). After adding water and stirring so that the partial concentration becomes 17%, the total amount of the obtained RF resin and 12.6 parts of 25% aqueous ammonia are added, mixed with stirring, and aged at 25 ° C. for 18 hours. a-1 to a-9 were obtained.
(Tire cord dipping treatment, cord strength and adhesive strength measurement)
Using a test single cord dipping machine, each 6-6 nylon tire cord (1890D / 2) was dipped in the obtained RFL solution, dried at 120 ° C. for 120 seconds, and then at 220 ° C. for 60 seconds. Baking was performed.
The cord strength of each tire cord subjected to the immersion treatment was measured according to JIS-L1017. The results are shown in Table 2. Each tire cord subjected to the immersion treatment was sandwiched with a rubber compound based on the compounding recipe in Table 3, and vulcanized and pressed at 160 ° C. for 20 minutes. Adhesion was measured according to ASTM D2138-67 (H Pull Test). The results are shown in Table 2.

Application example-2
(Adjustment of RFL solution)
After adding 4 parts of 10% sodium hydroxide to 260 parts of water and stirring, 7.9 parts of resorcin and 8.6 parts of 37% formalin are added and mixed by stirring, and aged at 25 ° C. for 6 hours. create. Next, the copolymer latex (A) and the copolymer latex (B) were mixed at the ratio (solid content) shown in Table 4 in 100 parts (solid content) of each of the copolymer latex (solid content). After adding water and stirring so that the partial concentration becomes 16.5%, the total amount of the obtained RF resin and 11.3 parts of 25% aqueous ammonia are added and mixed by stirring, and further 46.3 parts of 27% blocked isocyanate. The mixture was added, stirred and mixed, and aged at 25 ° C. for 18 hours to obtain RFL liquids b-1 to b-10.
(Tire cord dipping treatment, cord strength and adhesive strength measurement)
Using a test single cord dipping machine, each polyester cord (pretreated yarn 1500D / 2) was dipped in the obtained RFL solution, dried at 120 ° C. for 120 seconds, and then baked at 245 ° C. for 60 seconds. Went.
The cord strength of each tire cord subjected to the immersion treatment was measured according to JIS-L1017. The results are shown in Table 4. Further, each tire cord subjected to the immersion treatment was sandwiched with a rubber compound based on the formulation of Table 3, and vulcanized and pressed at 160 ° C. for 20 minutes and at 170 ° C. for 40 minutes. Adhesion was measured according to ASTM D2138-67 (H Pull Test). The results are shown in Table 4.

The present invention provides an improved copolymer latex for rubber and fiber adhesives suitable for bonding fibers and rubber (particularly ethylene-propylene rubber) contained in rubber products such as tires, belts and hoses.

Claims (2)

90 to 100% by weight of an aliphatic conjugated diene monomer and 0 to 10% by weight of another monomer copolymerizable therewith (excluding an ethylenically unsaturated carboxylic acid monomer) are emulsion-polymerized. 10 to 90 parts by weight (in terms of solid content) of the copolymer latex (A) obtained, 5 to 50% by weight of an aliphatic conjugated diene monomer, 5 to 25% by weight of a vinylpyridine monomer, and a copolymer thereof. Composed of 10 to 90 parts by weight (in terms of solid content) of copolymer latex (B) obtained by emulsion polymerization of 25 to 90% by weight of other possible monomers (however, the sum of (A) and (B) Is a copolymer latex for an adhesive of rubber and fiber. The copolymer latex according to claim 1, which is used for an adhesive between ethylene-propylene rubber and fiber.