KR20050044234A - Rubber composition for tread of snow tire - Google Patents

Abstract

The present invention provides a rubber composition for a snow tire tread comprising 1 to 10 parts by weight of a blowing agent, and 1 to 25 parts by weight of a core-shell rubber having a structure of at least one rigid core and at least one rigid shell, based on 100 parts by weight of raw rubber. As it provides, it is possible to obtain the effect of improving the wear resistance due to the addition of the core-shell rubber while maintaining the ice sheet braking performance due to the foamed rubber.

Description

Rubber composition for tread of snow tires {Rubber composition for tread of snow tire}

The present invention relates to a rubber composition for a snow tire tread, and more particularly, to a snow tire tread having improved wear resistance while maintaining ice braking performance, including a core-shell rubber having one flexible core and at least one rigid shell. It relates to a rubber composition.

In order to improve ice braking performance, foamed rubber is generally used, but foamed rubber has a disadvantage in that the block rigidity of the tire is reduced to deteriorate running stability and wear resistance.

In addition, the thermoplastic resin particles incorporating a thermosetting liquid or a solid is used to prevent the block deformation of the tire while improving ice braking performance. The method of forming a bubble inside is also used. Using this method, the ice sheet braking performance and the block rigidity of the tire can be improved, but the hollow thermoplastic resin particles exhibit a very low impact resistance at low temperatures, thereby degrading the durability and wear resistance of the tire tread rubber.

As a method for improving wear resistance while maintaining ice braking performance of a conventional tire, a method of adding a high hardness material to the tread rubber composition, that is, ceramic fine powder, short fibers, and metals is added, but the hardness of rubber and the loss of flexibility are increased. And other problems exist.

Therefore, the inventors of the present invention are looking for a method of improving the wear resistance while maintaining the ice sheet braking performance, which is a required property of the rubber composition for snow tire treads. As a result of the addition of a core-shell rubber having a flexible core and at least one rigid shell structure, it has been found that the abrasion resistance can be improved while maintaining ice braking performance.

Accordingly, an object of the present invention is to provide a rubber composition for a snow tire tread that can improve wear resistance while maintaining ice-break braking performance.

The rubber composition for snow tire tread of the present invention for achieving the above object includes a raw material rubber and a rubber compounding agent, based on 100 parts by weight of the raw material rubber 1 to 10 parts by weight of the blowing agent and one flexible core and at least one It is characterized in that it comprises 1 to 25 parts by weight of the core-shell rubber having a structure of the above rigid shell.

Referring to the present invention in more detail as follows.

The core-shell rubber included in the rubber composition for snow tire tread of the present invention has a structure of one flexible core and at least one rigid shell.

The flexible core is generally formed by polymerizing one or more selected from butadiene, isoprene, alkylacrylates, alkylmethacrylates or siloxane comonomers, where one or more monomers selected from graftable vinyl monomers are grafted onto the rubber This is a core-shell structure.

The vinyl monomers used in the production of the shell may be selected from one or more selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, acrylic ester monomers and maleimide monomers.

Here, as the aromatic vinyl monomer, styrene, t-butyl styrene, methyl styrene, vinyl toluene, monochloro styrene, dichloro styrene, dibromostyrene, ethyl styrene, vinyl naphthalene, divinyl benzene and the like can be used. Acrylonitrile, methacrylonitrile, ethacrylonitrile, etc. may be used as the vinyl cyanide monomer, and as the acrylic ester monomer, methyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, Butyl acrylate, glycidyl methacrylate, etc. can be used. The maleimide monomers include maleimide, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-dichlorohexylmaleimide, N-phenylmaleimide and N-trimaleimide Etc. can be used.

It is preferable to use a core-shell type rubber whose ratio of a core composition and a shell composition is a ratio of 1: 9-9: 1 weight ratio, or 3: 7-8: 2.

The core-shell rubber having such a role may be used in an amount of 1 to 25 parts by weight, preferably 5 to 15 parts by weight, based on 100 parts by weight of the raw material rubber.

On the other hand, the rubber composition for snow tire tread of the present invention contains a blowing agent to maintain the ice sheet braking performance.

Examples of the blowing agent include dinitrosopentamethylene tetraamine (DTP), azodicarbonamide (ADCA), oxybisbenzenesulfonylhydride (OBSH), and the like, and among them, oxybisbenzenesulfonylhydride is preferable. Do.

The content of the blowing agent is 1 to 10 parts by weight, preferably 2 to 8 parts by weight based on 100 parts by weight of the raw material rubber.

In addition, the rubber composition for snow tire tread of the present invention, of course, includes the raw material rubber, compounding agent used in the rubber composition for snow tire tread.

As the raw material rubber, natural rubber, butadiene rubber, styrene-butadiene rubber and the like can be used.

As the compounding agent, carbon black, silica, silica coupling agents, zinc oxide, stearic acid, oils, antioxidants, waxes, resins, sulfur, vulcanization accelerators and the like can be added.

Hereinafter, the present description will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Examples 1 to 3 and Comparative Example 1

The rubber sheet before vulcanization was mixed with the rubber and the additive by the conventional mixing method in the mixing ratio shown in Table 1 below, and the mixed rubber was vulcanized at 160 ° C. for 20 minutes to prepare a test specimen. The physical properties of the rubber composition thus prepared are shown in Table 2 below.

Compounding agent Example 1 Example 2 Example 3 Comparative Example 1 Natural rubber 100 100 100 100 Carbon black 70 70 70 70 Core-Shell Rubber 5 10 15 - Zinc oxide 3 3 3 3 Stearic acid 2 2 2 2 Aromatic oils 25 25 25 25 Anti-aging 3 3 3 3 Wax 2 2 2 2 brimstone 2 2 2 2 Vulcanization accelerator One One One One blowing agent 5 5 5 5 (1) Natural rubber: Dark brown to yellow ribbed smoke sheet according to international standard sample with diene natural rubber. (2) Carbon black: N2SA value is 95-m2 / g, dibutyl phthalate oil absorption 90- (3) Core-shell rubber: Core-shell rubber with methyl methacrylate monomer grafted to butadiene rubber, Paraloid EXL-2602 from Kureha, Japan

Properties Example 1 Example 2 Example 3 Comparative Example 1 Hardness (Shore A) 58 59 59 57 300% modulus (kgf / ㎠) 82 85 87 80 Elongation at Break (%) 480 475 470 490 Tensile strength (kgf / ㎠) 140 140 135 145 Rambon Wear Index 102 103 105 100 -20 ℃ G '(Mpa) 24.9 25.1 25.2 24.8

From the results of Table 2, the rubber compositions according to Examples 1 to 3, the G 'value of -20 ℃ is equal to or more than Comparative Example 1, the Rambon wear index can be seen that the index value is large, as a result It can be seen that wear resistance was improved while maintaining ice braking performance.

As described in detail above, the foamed rubber composition comprising a core-shell rubber having a flexible core and at least one rigid shell according to the present invention has improved wear resistance while maintaining ice braking performance, thereby improving snow tire tread rubber. Suitable as.

Claims (2)

In the rubber composition for snow tire tread containing the raw material rubber and rubber compounding agent, Rubber composition for snow tire treads, characterized in that it comprises 1 to 10 parts by weight of the blowing agent, and 1 to 25 parts by weight of the core-shell rubber having a structure of at least one rigid core and at least one rigid shell with respect to 100 parts by weight of the raw rubber. . The rubber composition for a snow tire tread according to claim 1, wherein the core-shell rubber is a core-shell rubber in which a methyl methacrylate monomer is grafted to a butadiene rubber.