CN-121991421-A - Tire tread rubber composition and preparation method thereof

Abstract

The invention relates to the technical field of rubber materials, and provides a tire tread rubber composition and a preparation method thereof, wherein the tire tread rubber composition comprises, by weight, 30-50 parts of total of left-handed polylactic acid grafted modified styrene-butadiene rubber and right-handed polylactic acid grafted modified styrene-butadiene rubber, 50-70 parts of star solution polymerized styrene-butadiene rubber, 65-75 parts of white carbon black, 10-18 parts of monomer resin, 5.2-7.0 parts of silane coupling agent, 2.8-4.2 parts of vulcanization system, 7.5 parts of rubber auxiliary agent, alpha-methyl styrene as the monomer resin, si-69 as the silane coupling agent, sulfur and accelerator as the vulcanization system, and zinc oxide, stearic acid and anti-aging agent as the rubber auxiliary agent. Two reinforcing networks with different properties exist in the composition at the same time, and the two reinforcing networks complement each other in structure and function and act together, so that the traditional restriction relation between the rolling resistance and the grip of the tire is successfully broken, and the cooperative improvement of the two reinforcing networks is realized.

Inventors

• ZHANG YULIANG
• YANG ZHENGUO
• Xie Haisu
• ZHAO RUIQING
• CHEN JIANJUN
• WANG YEJING
• XIAO SHENGLONG
• Xie Xiaohou
• WANG LING

Assignees

• 山东华盛橡胶有限公司
• 山东宏盛橡胶科技有限公司

Dates

Publication Date

20260508

Application Date

20260410

Claims (9)

1. 1. The tire tread rubber composition is characterized by comprising, by weight, 30-50 parts of total of left-handed polylactic acid grafted modified styrene-butadiene rubber and right-handed polylactic acid grafted modified styrene-butadiene rubber, 50-70 parts of star-shaped solution polymerized styrene-butadiene rubber, 65-75 parts of white carbon black, 10-18 parts of monomer resin, 5.2-7.0 parts of silane coupling agent, 2.8-4.2 parts of vulcanization system, 7.5 parts of rubber auxiliary agent, wherein the monomer resin is alpha-methylstyrene, the silane coupling agent is Si-69, the vulcanization system comprises sulfur and an accelerator, and the rubber auxiliary agent comprises zinc oxide, stearic acid and an anti-aging agent.
2. 2. The tire tread rubber composition according to claim 1, wherein the mass ratio of the left-handed polylactic acid graft-modified styrene-butadiene rubber to the right-handed polylactic acid graft-modified styrene-butadiene rubber is 0.8-1.2:1.
3. 3. The tire tread rubber composition of claim 1, wherein the grafting ratio of the L-polylactic acid grafted modified styrene-butadiene rubber is 5-15%, and the grafting ratio of the L-polylactic acid grafted modified styrene-butadiene rubber is 5-15%.
4. 4. The tire tread rubber composition according to claim 1, wherein the mass ratio of the total amount of the left-handed polylactic acid graft-modified styrene-butadiene rubber and the right-handed polylactic acid graft-modified styrene-butadiene rubber to the star-shaped solution-polymerized styrene-butadiene rubber is 0.8:1.
5. 5. The tire tread rubber composition according to claim 1, wherein the mass ratio of the star-shaped solution polymerized styrene-butadiene rubber to the white carbon black is 6:7.
6. 6. The tire tread rubber composition of claim 1, wherein the branched center point of the star solution polymerized styrene-butadiene rubber contains an alkoxysilane functional group.
7. 7. A preparation method of the tire tread rubber composition according to any one of claims 1 to 6 is characterized by comprising the steps of (1) respectively carrying out ring-opening polymerization reaction on levorotatory lactide and dextrorotatory lactide and hydroxyl-terminated styrene-butadiene liquid rubber in the presence of a catalyst to prepare levorotatory polylactic acid grafted modified styrene-butadiene rubber and dextrorotatory polylactic acid grafted modified styrene-butadiene rubber, (2) premixing the levorotatory polylactic acid grafted modified styrene-butadiene rubber and the dextrorotatory polylactic acid grafted modified styrene-butadiene rubber at a temperature of 80-100 ℃, 3) adding star-shaped solution polymerized styrene-butadiene rubber, monomer resin, white carbon black and a silane coupling agent for one-stage mixing, adding zinc oxide, stearic acid and an anti-aging agent for two-stage mixing, and (4) cooling a sizing material to a temperature of below 110 ℃ and adding a vulcanization system for final mixing.
8. 8. The method according to claim 7, wherein the catalyst in the ring-opening polymerization is stannous octoate, the reaction temperature is 110-130 ℃, and the reaction time is 12-24 hours.
9. 9. The method according to claim 7, wherein the first-stage kneading temperature is 140 to 160 ℃, the second-stage kneading temperature is 125 to 135 ℃, and the final-stage kneading temperature is 90 to 95 ℃.

Description

Tire tread rubber composition and preparation method thereof Technical Field The invention relates to the technical field of rubber materials, in particular to a tire tread rubber composition and a preparation method thereof. Background With the rapid development of the automobile industry and the continuous improvement of the global energy conservation and emission reduction requirements, the performance requirements of tires are increasingly stringent. The performance of the tire tread rubber, which is the part of the tire in direct contact with the road surface, directly affects the safety, economy and comfort of the vehicle. Rolling resistance and wet grip are two critical but mutually limiting performance indicators. The reduction of rolling resistance can improve the fuel economy of the automobile, and the improvement of the wet land grabbing force directly relates to driving safety. Conventional tire tread compound formulations often have difficulty optimizing both properties simultaneously, i.e., reducing rolling resistance while generally resulting in reduced grip and vice versa, a performance constraint that has long been a technical challenge for the tire industry. Solution polymerized styrene butadiene rubber (SSBR) has become the first choice of high performance tire tread rubber due to the advantages of strong designability of molecular structure, low rolling resistance, good wet skid resistance and the like. In the molecular design of SSBR, star-shaped solution polymerized styrene-butadiene rubber is of great interest because of its unique topology. Studies have shown that by synthesizing star polymers to reduce the number of free ends of molecular chains, hysteresis losses and heat generation can be significantly reduced, thereby reducing rolling resistance. The multi-arm structure of the star SSBR can form a more stable network structure in the mixing and vulcanization processes, and excellent mechanical property and dynamic property are endowed to the sizing material. In the aspect of a filler system, the white carbon black has become a main stream reinforcing filler of green tire tread rubber because of being capable of simultaneously reducing rolling resistance and improving wet skid resistance. However, silica-rich hydroxyl groups are present on the surface of white carbon black, the polarity is strong, agglomeration easily occurs in a nonpolar rubber matrix, and the dispersion is difficult. In order to improve dispersibility of the white carbon black, it is generally necessary to use a silane coupling agent for in-situ modification, and to link the white carbon black to a rubber molecular chain by a silylation reaction. In recent years, large tire enterprises and research institutions have developed extensive research and development efforts around low rolling resistance, high grip tire tread compounds. By adopting the composition of the modified solution polymerized styrene-butadiene rubber, white carbon black, high-performance resin and the like, the wet grip performance and the dry grip performance of the rubber material are improved on the premise of achieving the aim of ultralow rolling resistance. Despite the advances made in the art with respect to low roll resistance, high grip, the following deficiencies still remain: First, the conventional SSBR modification strategy mainly focuses on the functionalization modification of molecular chain ends, and the interface enhancement effect is limited by introducing a single functional group to interact with white carbon black. Although the star structure can reduce the number of free ends and hysteresis loss, there is still a great room for improvement in terms of further improving the bonding strength of the filler-rubber interface and constructing a reversible physical cross-linked network. Secondly, in the prior art, the interface effect of the white carbon black and the rubber matrix mainly depends on the chemical bonding of the silane coupling agent, and the single interface effect mode is easy to generate interface damage under dynamic load, so that the long-term durability is influenced. How to construct a multiple interface enhancement mechanism to enable a white carbon black reinforcement network and a rubber molecular chain to form a more stable interaction is a key for improving the comprehensive performance of tread rubber. Accordingly, the prior art is subject to further development. Disclosure of Invention Aiming at overcoming various defects in the prior art, in order to solve the problems, a tire tread rubber composition and a preparation method thereof are provided, and the following technical scheme is provided: The tire tread rubber composition comprises, by weight, 30-50 parts of total of left-handed polylactic acid graft modified styrene-butadiene rubber and right-handed polylactic acid graft modified styrene-butadiene rubber, 50-70 parts of star-shaped solution polymerized styrene-butadiene rubber, 65-75 parts of