Block Copolymer Rubber Composition for Tire Tread
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Solution Overview
Problem
Current rubber compositions for tire treads face challenges in achieving a balance between low rolling resistance, wet skid resistance, mechanical strength, and wear resistance, particularly when using silica or carbon black as fillers, and existing solutions do not adequately address these requirements.
Innovation Solution
A rubber composition incorporating a block copolymer with distinct glass transition temperatures, specifically a polymer block derived from a conjugated diene compound and an aromatic vinyl compound, combined with other rubber components and fillers like silica or carbon black, to create a homogeneous and high-performance rubber elastic body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rubber composition uses silica or carbon black as filler to reduce rolling resistance, then low rolling resistance is improved, but wet skid resistance and mechanical strength deteriorate
Solution Approach 1:
The invention uses a composite rubber composition containing both silica and carbon black as fillers, along with specific rubber components (modified conjugated diene polymer, block copolymer, and natural rubber) to achieve a balance between low rolling resistance and wet skid resistance. The composite structure allows synergistic effects of different fillers and polymers to improve both properties simultaneously.
Solution Approach 2:
The invention optimizes the glass transition temperatures of the rubber components, specifically using a block copolymer with a low glass transition temperature (-80°C to -40°C) to improve wet skid resistance while maintaining low rolling resistance. The specific parameter optimization of Tg values allows the rubber to exhibit desirable properties at different service temperatures.
2Loss of energy
If a rubber composition uses silica or carbon black as filler to improve low rolling resistance, then mechanical strength deteriorates
Solution Approach 1:
The invention employs a composite system with both silica and carbon black fillers combined with specific rubber polymers. The carbon black provides reinforcement for mechanical strength while silica contributes to low rolling resistance, creating a synergistic composite that achieves both goals simultaneously.
Solution Approach 2:
The invention assigns different functional roles to different components: carbon black primarily provides mechanical strength and abrasion resistance, while silica primarily reduces rolling resistance. The block copolymer with specific Tg range provides wet skid resistance. This local functional differentiation allows each component to excel at its specific function without compromising overall performance.
3Loss of energy
If a rubber composition uses silica or carbon black as filler to reduce rolling resistance, then wear resistance deteriorates
Solution Approach 1:
The composite rubber composition utilizing both silica and carbon black fillers, combined with耐磨 rubber components, creates a synergistic effect where carbon black provides abrasion resistance and silica reduces rolling resistance, achieving both wear resistance and low rolling resistance simultaneously.
Solution Approach 2:
The invention optimizes the glass transition temperature parameters of the rubber components, particularly using a block copolymer with Tg of -80°C to -40°C, to enhance the rubber's durability and wear resistance while maintaining low rolling resistance properties through controlled molecular mobility and energy dissipation characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a rubber elastic body with excellent low rolling resistance, wet skid resistance, mechanical strength, and wear resistance, suitable for tire treads, by ensuring the fillers are evenly distributed and the block copolymer's functional groups enhance compatibility and properties.
Implementation Method 1
a polymer block (a-2) comprising a structural unit derived from a conjugated diene compound... at least one functional group selected from the group consisting of an amino group, an imino group, a pyridyl group, a piperazyl group, and a thiol group... the block copolymer's functional groups enhance compatibility
Implementation Method 2
a glass transition temperature of the polymer block (a-2) is lower than a glass transition temperature of the polymer block (a-1)... two glass transition temperatures separated from each other by 5°C or more within a range of -100 to 20°C
Data Source
AI summary
A rubber composition by which a rubber elastic body having both of excellent low rolling resistance and wet skid resistance and also having excellent mechanical strength and wear resistance can be obtained, a rubber elastic body, a tire, and a block copolymer are provided. The rubber composition of the present invention comprises a block copolymer (A) comprising a block (a-1) of a conjugate diene and an aromatic vinyl and a block (a-2) of a conjugate diene or the diene and an aromatic vinyl, a specific polymer (B) other than the copolymer, and a filler (C), wherein the block copolymer (A) has a specific functional group; the block copolymer (A) has two glass transition temperatures separated from each other by 5°C or more within a range of -100 to 20°C in measurement in accordance with ASTM D3418; and the ratio of the block copolymer (A) is 10% by mass or more when the sum of the block copolymer (A) and the polymer (B) is taken as 100% by mass.