US-12623490-B2 - Adhesive composition for tire cord, tire cord, and tire

Abstract

This invention relates to an adhesive composition for a tire cord, a tire cord including an adhesive layer formed from the adhesive composition, and a tire including the tire cord. According to the present disclosure, an environment-friendly adhesive composition for a tire cord that can not only improve adhesive strength between tire rubber and a tire cord, but can also improve strength of a tire cord is provided.

Inventors

• Sung Gyu LEE
• Il Chung
• Ok Hwa JEON
• Min Ho Lee

Assignees

• KOLON INDUSTRIES, INC.

Dates

Publication Date

20260512

Application Date

20210409

Priority Date

20200409

Claims (12)

1. 1 . An adhesive composition for a tire cord, comprising: a reaction product of an epoxy resin and a diol compound; an isocyanate compound; latex; water-dispersed polyurethane; an amine compound; and a solvent, wherein the reaction product is formed by reaction between the epoxy resin and the diol compound at a weight ratio of 1:0.1 to 1:5, and the reaction product has a weight average molecular weight of 700 to 1200 g/mol, wherein the diol compound comprises one or more selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, and 1,6-hexanediol.
2. 2 . The adhesive composition for a tire cord according to claim 1 , wherein the composition comprises: 0.5 to 10.0 wt % of the reaction product; 1.0 to 20.0 wt % of the isocyanate compound; 1.0 to 30.0 wt % of the latex; 0.5 to 10.0 wt % of the water-dispersed polyurethane; 0.1 to 10.0 wt % of the amine compound; and 60.0 to 85.0 wt % of the solvent.
3. 3 . The adhesive composition for a tire cord according to claim 1 , wherein the epoxy resin comprises one or more selected from the group consisting of a bisphenol-based epoxy resin, a novolac-based epoxy resin, and an oxazolidone-based epoxy resin.
4. 4 . The adhesive composition for a tire cord according to claim 1 , wherein the isocyanate compound comprises one or more selected from the group consisting of methylene diphenyl diisocyanate, toluene diisocyanate, and hexamethylene diisocyanate.
5. 5 . The adhesive composition for a tire cord according to claim 1 , wherein the latex comprises one or more selected from the group consisting of a vinylpyridine-styrene-butadiene-based copolymer latex and a modified latex thereof, a styrene-butadiene latex and a modified latex thereof, a natural rubber latex, an acrylic acid ester copolymer latex, a butyl rubber latex, and a chloroprene rubber latex.
6. 6 . The adhesive composition for a tire cord according to claim 1 , wherein the water-dispersed polyurethane comprises one or more selected from the group consisting of a polycarbonate-based urethane, a polyester-based urethane, a polyacryl-based urethane, a polytetramethylene-based urethane, a polycaprolactone-based urethane, a polypropylene-based urethane, and a polyethylene-based urethane.
7. 7 . The adhesive composition for a tire cord according to claim 1 , wherein the amine compound comprises one or more selected from the group consisting of an aliphatic amine and an alicyclic amine.
8. 8 . The adhesive composition for a tire cord according to claim 1 , wherein the solvent is water.
9. 9 . The adhesive composition for a tire cord according to claim 1 , wherein the composition has a relative viscosity measured using an Ubbelohde viscometer at 25° C. of 2.0 to 3.0.
10. 10 . A tire cord comprising: a fiber substrate; and an adhesive layer formed on the fiber substrate, and formed from the adhesive composition for a tire cord of claim 1 .
11. 11 . The tire cord according to claim 10 , wherein the fiber substrate is a raw cord comprising a polyester fiber.
12. 12 . A tire comprising the tire cord of claim 10 .

Description

CROSS REFERENCE TO RELATED APPLICATION(S) This application is a National Stage of International Application No. PCT/KR2021/004456 filed on Apr. 9, 2021 claiming the benefit of Korean Patent Application No. 10-2020-0043566 filed on Apr. 9, 2020, and Korean Patent Application No. 10-2021-0045707 filed on Apr. 8, 2021 in the Korean Intellectual Property Office, each of which is incorporated herein by reference in its entirety. TECHNICAL FIELD This invention relates to an adhesive composition for a tire cord, a tire cord including an adhesive layer formed from the adhesive composition, and a tire including the tire cord. BACKGROUND OF ART In order to reinforce the strength of rubber structures, fiber reinforcing materials are used. For example, in rubber tires, polyester fiber, polyamide fiber, aromatic polyamide fiber, polyvinyl alcohol fiber, and the like may be used as reinforcing materials. In some cases, adhesion between fiber and rubber is not good according to the fiber, and thus, an adhesive is coated on the surface of the fiber to supplement adhesion between the fiber and the rubber. For example, in order to improve adhesive strength between a raw cord for a tire cord and tire rubber, the adhesive is coated on the polyester fiber. In general, in the adhesive composition for the above purpose, rubber (or latex) including resorcinol-formaldehyde (hereinafter, referred to as “RF”) or a component derived therefrom is included. However, as RF resin is harmful to the human body and the environment, its use is being strictly regulated. Thus, studies on adhesive compositions that do not include RF resin are being constantly progressed. The adhesive composition may be provided on the fiber reinforcing material by dipping or spraying. Not only should the adhesive composition have appropriate flowability, but also the solid contents should be uniformly dispersed, so that property improvement effects according to the adhesive composition may be sufficiently and uniformly exhibited. Meanwhile, although the adhesive composition improves adhesive strength between the fiber reinforcing material and tire rubber, stiffness of the fiber reinforcing material may be changed due to the adhesive composition. In case stiffness of the fiber reinforcing material increases more than needed, strength of the fiber reinforcing material may decrease, and as a result, the properties of a tire including the same may be deteriorated. DETAILED DESCRIPTION OF THE INVENTION Technical Problem It is an object of the invention to provide an environment-friendly adhesive composition for a tire cord that can not only improve adhesive strength between tire rubber and the tire cord, but also improve strength of the tire cord. It is another object of the invention to provide a tire cord having high adhesive strength and improved strength. It is yet another object of the invention to provide a tire including the tire cord. Technical Solution Hereinafter, an adhesive composition for a tire cord, a tire cord, and a tire according to the embodiments of the invention will be explained in detail. Technical terms in the present specification are only for mentioning specific embodiments, and they are not intended to restrict the invention unless there is a particular mention about them. A singular expression includes a plural expression thereof, unless it is expressly stated or obvious from the context that such is not intended. As used herein, the terms “comprise” or “have”, etc. are intended to designate the existence of practiced characteristics, numbers, steps, constructional elements, or combinations thereof, and they are not intended to preclude the possibility of existence or addition of one or more other characteristics, numbers, steps, constructional elements, or combinations thereof. According to the results of continued studies of the inventors, a reaction product between an epoxy resin and a diol compound has a large molecule size compared to the original epoxy resin, and has a relatively high soft segment rate in the molecule. Thus, an adhesive composition for a tire cord including the reaction product may be applied to any fiber substrate to provide excellent adhesive strength and appropriate stiffness, and enable realization of improved strength. According to one embodiment of the invention, there is provided an adhesive composition for a tire cord, including: a reaction product of an epoxy resin and a diol compound;an isocyanate compound;latex;a water-dispersed polyurethane;an amine compound; anda solvent. The adhesive composition for a tire cord does not include the RF resin, and thus, it does not induce environmental pollution and enables improvement in a working environment. In the adhesive composition for a tire cord, a reaction product of an epoxy resin and a diol compound is included. The reaction product of an epoxy resin and a diol compound has epoxy functional groups, thus improving reactivity and adhesion of the adhesive composi