JP7318347B2 - latex adhesive composition - Google Patents

Description

The present invention provides a latex adhesive composition containing polychloroprene rubber latex, more specifically, a latex adhesive capable of achieving both excellent adhesive strength and flexibility in adhesion between foams or between foams and textiles. It relates to compositions.

Various foams are used as adherends in the manufacture of wet suits, supporters, insoles for sports shoes, shock absorbers, and the like. Conventionally, solvent-based adhesives based on polychloroprene rubber or the like have been used for these adhesions. However, volatilization of the organic solvents used in these adhesives causes health problems for workers and fires in the workplace. I came

Further, conventional polychloroprene rubber latex has a problem of insufficient adhesive strength. As a method for solving this problem, an adhesive composition containing polychloroprene latex as a main component and a water-dispersed polyisocyanate as a cross-linking agent and a method for bonding the same are known in adhesion to foam (for example, See Patent Documents 1 and 2.). However, since the adhesive composition film is cured by isocyanate, although the adhesive strength is improved, there is a problem that the flexibility of the foam after adhesion is impaired. As a method for solving this problem, an adhesive composition containing polychloroprene latex as a main component and a water-dispersed carbodiimide compound as a cross-linking agent and a method for bonding the same are known in adhesion to foam (for example, , see Patent Document 3). However, although the flexibility is good, there is a problem that the adhesive strength is insufficient and the toluene resistance required especially in the wet suit manufacturing process is insufficient.

Japanese Patent Application Laid-Open No. 2000-104028 Japanese Unexamined Patent Application Publication No. 2003-27024 JP 2018-168327 A

The present invention has been made in view of this problem. To provide a latex adhesive composition having good adhesive strength and flexibility in adhesion between foams used as materials for goods and wet suits, or between foams and textiles.

In view of this background, the present inventors have made intensive studies to solve the above problems, and have found that by mixing a non-aqueous dispersion type isocyanate with polychloroprene rubber latex, adhesion of polychloroprene rubber latex as a main component can be achieved. The inventors have found that it is possible to improve the adhesive strength between the agent composition and the foam, and have completed the present invention.

That is, the present invention provides a latex adhesive composition containing 2.0 to 8.0 parts by weight of a non-aqueous dispersion type isocyanate compound and 7.0 parts by weight or less of a water-soluble carbodiimide compound per 100 parts by weight of polychloroprene rubber latex. It is a thing.

The present invention will be described in detail below.

The latex adhesive composition of the present invention contains 2.0 to 8.0 parts by weight of a non-aqueous dispersion type isocyanate compound per 100 parts by weight of polychloroprene rubber latex.

Various products of polychloroprene rubber latex are commercially available. There are latexes of copolymers with monomers and the like. Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, fumaric acid and maleic acid, and examples of hydroxyl group-containing monomers include hydroxyethyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

The polychloroprene latex is not particularly limited, but polychloroprene rubber latex containing a copolymer with one or more monomers is preferred because polychloroprene rubber hardens due to crystallization at low temperatures.

The latex adhesive composition of the present invention must contain a non-water-dispersible isocyanate compound in order to achieve both sufficient adhesive strength and flexibility.

The isocyanate compound is a compound having a functional group represented by -N=C=O, and some of them are water-dispersible (dispersion type) that can be dispersed in water by modification treatment or the like. A non-aqueous dispersion type that has not been treated is used. Although the content of isocyanate groups (NCO) is not particularly limited, it is generally 12 to 23%, preferably 15 to 21% from the balance of cost and pot life. As the skeleton of the isocyanate compound, those having a trimer-type or allophanate-type skeleton are known, and although either type can be used in the present invention, the trimer-type generally has better adhesive strength. The allophanate type is superior in terms of flexibility.

The adhesive composition of the present invention can increase adhesive strength by containing a carbodiimide compound. A carbodiimide compound is a compound having a functional group represented by -N=C=N- and is generally synthesized by a decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidation catalyst. The NCN content is generally about 5 to 15%, preferably 10% or more because of its high reactivity. A carbodiimide compound is partially hydrophilized or emulsified with an emulsifier or the like to take various forms such as water-based, emulsified, and water-dispersed types, and various commercial products exist. Among these, the water-soluble type is preferable from the viewpoint of toluene resistance and flexibility, and the emulsified type and water-dispersible type are preferably not used because they impair the flexibility.

The non-aqueous dispersion type isocyanate compound used in the present invention is 2.0 to 8.0 parts by weight, preferably 3.0 to 7.0 parts by weight, more preferably 4.0 parts by weight, based on 100 parts by weight of polychloroprene rubber. ~5.0 parts by weight. If the amount of the non-aqueous-dispersible isocyanate compound is less than 2 parts by weight, the adhesion property is lowered, and if it exceeds 8.0 parts by weight, the flexibility of the adherend is lowered. Water-soluble carbodiimide compound is 7.0 parts by weight or less per 100 parts by weight of polychloroprene rubber, more preferably 2.0 to 6.0 parts by weight, more preferably 3.0 parts by weight per 100 parts by weight of polychloroprene rubber. ~5.0 parts by weight. By setting the amount of the water-dispersible carbodiimide compound to 7.0 parts by weight or less, the adhesive composition has good adhesion properties and coatability.

The viscosity of the latex adhesive composition is controlled by various thickeners, such as water-soluble polymers such as polyalkylene oxide, polyvinyl alcohol, hydrophobized cellulose, associative nonionic surfactants, and carboxyl group-containing polymers. The desired viscosity can be adjusted by adding a soluble thickener, a silicate compound such as hectorite, or the like. At this time, it is preferable to use polyethylene oxide because the coatability is good at the time of coating by roll coating. Polyethylene oxide is preferably contained in an amount of 0.05 to 1.0 parts by weight per 100 parts by weight of polychloroprene rubber latex. If necessary, tackifying resins such as rosin esters, terpene phenols, petroleum resins and coumarone resins, anti-aging agents, preservatives, anti-freezing agents, film-forming aids, plasticizers, pH adjusters, etc. can be

The adhesive composition of the present invention is used for bonding foams to each other, or foams and textiles, which are materials for sports goods, wet suits, and the like.

Sporting goods and other foams may include foams molded from polychloroprene rubber, ethylene-vinyl acetate copolymer, chlorosulfonated polyethylene, styrene-butadiene rubber, and the like. On the other hand, polychloroprene rubber and the like are used as foams for wet suits.

Textiles include synthetic fibers such as nylon and polyester, and non-woven fabrics made of natural fibers such as cotton and silk. For wet suits, jerseys with water-repellent properties are used.

The adhesive composition of the present invention exhibits excellent adhesive strength between foams and between foams and textiles, and the adhesive maintains excellent flexibility and toluene resistance.

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited only to these examples.

The room-temperature peel strength and flexibility in the examples were measured and evaluated by the following methods.
<Measurement of normal temperature peel strength>
After curing the adhered sample at 23° C. for 1 day in a constant temperature room, it was punched out with a cutting machine of 25 mm×150 mm to prepare a test piece. The end of each adherend was attached to a Tensilon tensile tester, and a 180° peel test was conducted at 23°C at a tensile speed of 20 mm/min to observe the state of peeling.

The peeling state was judged as follows.

(Good) Material failure (material failure) > Cohesive failure (cohesion) > Interfacial failure (interface) (Poor)
<Measurement of toluene resistance>
After the adhered sample was cured in a constant temperature room at 23° C. for 7 days, a normal-temperature peeling test was carried out using a Tensilon tensile tester while toluene was dripped onto the sample, and the state of peeling was observed. The peel strength was measured when the material did not break.

The peeling state was judged as follows.

(Good) Material failure (material failure) > Cohesive failure (cohesion) > Interfacial failure (interface) (Poor)
<Measurement of flexibility>
After curing the adhered sample at 23° C. for 7 days in a constant temperature room, it was punched out with a cutting machine of 25 mm×150 mm to prepare a test piece. Both ends of the test piece were attached to a Tensilon tensile tester, and tensile stress at 60% elongation at 23° C. was measured at a tensile speed of 100 mm/min.

Example 1
Polychloroprene rubber latex (manufactured by Tosoh Corporation, chloroprene-methacrylic acid copolymer, trade name: Skyprene GFL-890) 100 parts by weight, non-aqueous dispersion type isocyanate compound A (manufactured by Tosoh Corporation, trade name: Coronate C -2793, NCO 16.4%) 4 parts by weight, water-soluble carbodiimide compound (manufactured by Nisshinbo Chemical Co., Ltd., trade name: Carbodilite V-04, active ingredient 40%) 10 parts by weight (pure content 4 parts by weight), association type 2.5 parts by weight of a viscosity modifier (manufactured by Adeka Co., Ltd., trade name: ADEKA NOL UH-438) and a 10% aqueous solution of a polyethylene oxide compound (manufactured by Sumitomo Seika Co., Ltd., trade name: PEO-1, white powder) An adhesive composition was prepared by uniformly mixing 1 part by weight with a homomixer. About 80 g/m ² (wet) of the adhesive composition was applied to a sponge piece made of chloroprene rubber, water-repellent nylon jersey was layered so as not to cause wrinkles, and an iron plate weighing about 10 kg was placed on it for 90 seconds in an oven at 100°C. Pressure dried.

In the peeling test, the sponge material was mainly broken, and in the toluene resistance test, the room temperature peeling strength was high, the tensile stress of the test piece was low, and the flexibility was good.

Example 2
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the non-aqueous dispersion type isocyanate compound to be mixed was changed to the amount shown in Table 1. In the peeling test, the sponge material was mainly broken, and in the toluene resistance test, the room temperature peeling strength was high, the tensile stress of the test piece was low, and the flexibility was good.

Example 3
An adhesive composition was prepared and evaluated according to Example 1 except that the non-aqueous dispersion type isocyanate compound to be mixed was changed to isocyanate compound B (manufactured by Tosoh Corporation, trade name: Coronate C-2785, NCO 19.2%). did In the peel test, the sponge material was mainly broken, and both the room temperature peel strength and flexibility were good results.

Examples 4 and 5
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the water-soluble carbodiimide compound to be mixed was changed to the amount shown in Table 1. In the peel test, the sponge material was mainly broken, and both the room temperature peel strength and flexibility were good results.

Example 6
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the water-soluble carbodiimide compound to be mixed was changed to the amount shown in Table 1. The flexibility was good and the adhesive peel strength was high and good.

Reference example 7
An adhesive composition was prepared and evaluated according to Example 1, except that the water-soluble carbodiimide was not mixed. In the peel test, the sponge material was mainly broken, and both the room temperature peel strength and flexibility were good results.

Reference example 8
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the non-aqueous dispersible isocyanate compound to be mixed was changed to the amount shown in Table 1, and the water-soluble carbodiimide was not mixed. In the peel test, the sponge material was mainly broken, and both the room temperature peel strength and flexibility were good results.

Table 1 shows the compositions and evaluation results of the samples prepared in Examples 1 to 6 and Reference Examples 7 and 8.

Comparative example 1
An adhesive composition was prepared and evaluated according to Example 1, except that the isocyanate compound to be mixed was changed to a water-dispersible isocyanate compound (manufactured by Tosoh Corporation, trade name: Coronate AQ-140, NCO 18.0%). rice field. Adhesive physical properties at room temperature were good, but flexibility and toluene resistance were poor.

Comparative example 2
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the non-aqueous dispersion type isocyanate to be mixed was changed to the amount shown in Table 2. Flexibility was good, but adhesive physical properties were poor.

Comparative example 3
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the non-aqueous dispersion type isocyanate to be mixed was changed to the amount shown in Table 2. It was difficult to apply the adhesive composition, resulting in poor adhesion.

Comparative example 4
An adhesive composition was prepared and evaluated according to Example 1, except that the weight of the water-soluble carbodiimide compound to be mixed was changed to the amount shown in Table 2. It was difficult to apply the adhesive composition, resulting in poor adhesion.

Reference Example Polychloroprene rubber latex (manufactured by Tosoh Corporation, chloroprene-methacrylic acid copolymer, trade name: Skyprene GFL-890) 100 parts by weight, water-dispersible carbodiimide compound (manufactured by Nisshinbo Chemical Co., Ltd., trade name: Carbodilite E-05 (40% active ingredient) 4.0 parts by weight and 2.5 parts by weight of associative viscosity modifier (manufactured by Adeka Co., Ltd., trade name: ADEKA NOL UH-438) are uniformly mixed with a homomixer and adhered. A composition was prepared and tested under the conditions of Example 1. Adhesive physical properties and flexibility at room temperature were good, but toluene resistance was poor.

Table 2 shows the compositions and evaluation results of samples prepared in Comparative Examples 1 to 4 and Reference Example.

Claims (8)

Latex adhesion characterized by containing 2.0 to 8.0 parts by weight of a non-aqueous dispersion type isocyanate compound and 2.0 to 6.0 parts by weight of a water-soluble carbodiimide compound with respect to 100 parts by weight of polychloroprene rubber latex. agent composition. The polychloroprene rubber in the polychloroprene rubber latex is a copolymer of a chloroprene monomer and one or more monomers selected from carboxyl group-containing monomers and hydroxyl group-containing monomers. The latex adhesive composition of Claim 1. 3. The latex adhesive composition according to claim 1, wherein the content of the non-water-dispersible isocyanate compound is 3.0 to 7.0 parts by weight. 4. The latex adhesive composition according to any one of claims 1 to 3 , which does not contain an emulsifying dispersion type carbodiimide compound. The latex adhesive composition according to any one of claims 1 to 4, characterized by containing 0.05 to 1.0 parts by weight of polyethylene oxide with respect to 100 parts by weight of polychloroprene rubber latex. An adhesive body in which foams are bonded together or foams and textiles are bonded with the latex adhesive composition according to any one of claims 1 to 5 . 7. The adhesive body according to claim 6 , wherein the material of the foam is polychloroprene rubber. A wet suit comprising the adhesive body according to claim 6 or 7 .