CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2019-0060499, filed on May 23, 2019, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a rubber composition for tire tread and a tire manufactured by using the same, and more specifically, to a rubber composition for tire tread, the rubber composition which improves rolling resistance and abrasion resistant performance and improves handling performance and braking performance on wet, and ice and snow road surfaces at the same time, and a tire manufactured by using the same.

2. Description of Related Art

Environmental issues due to global warming, fine dust, and others in addition to the problem of high oil prices due to oil exhaustion have been globally considered as big issues. Accordingly, much effort has been made in an automotive industry to improve such environmental issues. In order to improve fuel efficiency and reduce environmental pollutant discharge amount, automobile manufacturers have been developing and released hybrid vehicles and electric vehicles, and new electric vehicle manufacturers instead of existing automobile manufacturers have also been created. A tire industry is trying to increase fuel efficiency of vehicles by reducing energy losses due to rolling resistance of tires.

According to the labelling system that has been globally enforced started in Europe since 2012, grades for braking performance, fuel efficiency performance and noises on a wet road surface are provided to consumers in a state that the grades are marked, and a domestic market has also been enforcing an energy consumption efficiency grade system in line with such a global trend.

Therefore, since the tire industry has been focusing on developing labelled performance-oriented products, there is a trade-off tendency in which the other performance becomes unfavorable to improve one performance. Such performances include abrasion resistant performance which may have an effect on purchase cycle of consumers, snow performance affecting ice and snow braking performance and handling performance in the wintertime, and fatigue resistant performance determining long-term stability.

A tire industry in European market is divided into summer tires and winter tires, while North American and domestic primary sales markets are mainly a market for all season tires. Recently, a market environment that had been divided into two markets for the summer tires and winter tires has been gradually grown into a market environment that is the market for all season tires with the development of the North American market. Since the all-season tires are used in the wintertime as well as the summertime without replacing the tires, the all-season tires require braking performance on an ice and snow road surface as well as braking performance and abrasion resistance performance on a wet road surface. However, since such braking performance on the ice and snow road surface as well as braking performance and abrasion resistance performance on the wet road surface are performances conflicting with each other, physical properties showing the braking performance on the wet road surface of the rubber composition are improved while the braking performance on the ice and snow road surface is deteriorated when increasing glass transition temperature of a rubber composition or increasing content of a reinforcing agent to improve the braking performance on the wet road surface.

General tires are used in a wide temperature range from −20° C. to 40° C. However, when conducting an operation of driving a vehicle for a long time on a high temperature asphalt of which temperature is increased up to 40° C. in the middle of summer, a tire use temperature range may allow synthetic oil, which is used for facilitating processing of rubber, to flow out to the outside from the inside of a tread, and may finally cause a change in elastic properties of rubber. Therefore, the tire use temperature range has been recognized as a risk factor in tire driving stability.

In order to overcome such a problem of an existing technique, it is necessary to develop a technology for a rubber composition for tire tread, the rubber composition which is capable of improving rolling resistance, abrasion resistant performance, and handling and braking performances on a wet road surface and an ice and snow road surface at the same time.

RELATED ART DOCUMENT

Patent Document

(Patent document 1) Korean Patent Laid-Open Publication No. 10-2016-0124822 (Oct. 28, 2016)

SUMMARY OF THE INVENTION

An objective of the present disclosure is to provide a rubber composition for tire tread, the rubber composition which improves rolling resistance and abrasion resistant performance and improves handling and braking performances on a wet road surface and an ice and snow road surface at the same time.

The other objective of the present disclosure is to provide a tire manufactured by using the rubber composition for tire tread.

Technical Solution

A rubber composition for tire tread according to an aspect of the present disclosure is provided, the rubber composition for tire tread comprises 100 parts by weight of raw rubber and 70 to 120 parts by weight of a reinforcing filler, wherein the raw rubber includes 0 to 50 parts by weight of natural rubber, 20 to 100 parts by weight of a melt grafting-functionalized styrene butadiene rubber, and 0 to 30 parts by weight of butadiene rubber.

In the rubber composition for tire tread, the melt grafting-functionalized styrene butadiene rubber may introduce a peroxide and an acrylate-based or methacrylate-based functional group using an emulsion-polymerized or solution-polymerized styrene butadiene rubber.

In the rubber composition for tire tread, the melt grafting-functionalized styrene butadiene rubber may include 20 to 50 wt % of styrene, and have 10 to 40 wt % of vinyl contained in butadiene.

In the rubber composition for tire tread, the melt grafting-functionalized styrene butadiene rubber may have a glass transition temperature of −50 to −10° C., and may include 10 to 40 parts by weight of oil with respect to 100 parts by weight of the melt grafting-functionalized styrene butadiene rubber.

In the rubber composition for tire tread, the acrylate-based functional group may be selected from the group consisting of 2-carboxyethyl acrylate, methyl acrylate, ethyl acrylate, ethylene glycol methyl ether acrylate, vinyl acrylate, 2-hydroxyethyl acrylate, isooctyl acrylate, octyl acrylate, and combinations thereof, and the methacrylate-based functional group may be selected from the group consisting of methyl methacrylate, 2-(diethylamino)ethyl methacrylate, polymethylmethacrylate, poly(ethylene glycol)methacrylate, hydroxypropyl methacrylate, ethylene glycol methyl ether methacrylate, 2-(dimethylamino)ethyl methacrylate, 2-(diethylamino)ethyl methacrylate, glycidyl methacrylate, and combinations thereof.

In the rubber composition for tire tread, the butadiene rubber may include 90 wt % or more of cis-1,4-butadiene and may have a glass transition temperature of −100 to −120° C.

In the rubber composition for tire tread, the reinforcing filler may include 5 to 20 parts by weight of carbon black and 65 to 100 parts by weight of silica.

In the rubber composition for tire tread, the silica may be high dispersibility silica having a nitrogen adsorption specific surface area of 160 to 180 m2/g and a CTAB adsorption specific surface rea of 150 to 170 m2/g.

Furthermore, a tire according to the other aspect of the present disclosure manufactured by using the rubber composition for tire tread is provided.

A rubber composition for tire tread according to the present disclosure may provide a tire which improves rolling resistance and abrasion resistant performance and has improved handling and braking performances on a wet road surface and an ice and snow road surface at the same time.

