Star-Shaped Block Copolymer Rubber for Tire Tread
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Solution Overview
Problem
Current rubber materials struggle to achieve a balance between low rolling resistance, excellent wet skid resistance, and good abrasion resistance, with single rubbers often compromising on one property to improve another.
Innovation Solution
A copolymer rubber with a star-shaped block structure comprising styrene, isoprene, and butadiene monomers, along with a coupling agent, is developed, allowing for a balanced combination of properties through specific molecular weight ranges and linkage contents, and a proprietary polymerization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cis-1,4-polybutadiene rubber is used to achieve flexibility and abrasion resistance, then wet skid resistance deteriorates
Solution Approach 1:
The patent creates a composite rubber material integrating three different rubber phases (polybutadiene, polyisoprene, and styrene-butadiene copolymer) within a single molecular structure. This composite approach allows the material to simultaneously exhibit abrasion resistance from polybutadiene, flexibility from polyisoprene, and wet skid resistance from styrene-butadiene copolymer, resolving the contradiction between abrasion resistance and wet skid resistance.
Solution Approach 2:
The patent segments the rubber molecule into distinct blocks, each with specific functions: polybutadiene blocks for abrasion resistance, polyisoprene blocks for flexibility, and styrene-butadiene copolymer blocks for wet skid resistance. This segmentation allows each block to contribute its specific property without compromising the others, enabling simultaneous achievement of multiple contradictory properties.
2Reliability
If styrene butadiene rubber is used to achieve wet skid resistance, then rolling resistance worsens
Solution Approach 1:
The patent applies local quality by concentrating styrene-butadiene copolymer blocks specifically at the chain ends of the rubber molecule, where they provide wet skid resistance through their polar groups. The main chain body consists of polybutadiene and polyisoprene blocks that maintain low rolling resistance. This localized placement allows wet skid resistance improvement without significant increase in overall rolling resistance.
3Strength
If natural rubber is used to achieve moderate flexibility and rolling resistance, then wet skid resistance deteriorates
Solution Approach 1:
The patent merges natural rubber's polyisoprene structure with synthetic polybutadiene and styrene-butadiene copolymer blocks into a single copolymer molecule. This merging combines the flexibility advantage of natural rubber with the wet skid resistance of styrene-butadiene copolymer and the abrasion resistance of polybutadiene, achieving a balanced performance that natural rubber alone cannot provide.
Data Source
AI summary
Provided is a copolymer rubber, comprising a copolymer having a star-shaped block structure (SIB-PA)n-X, wherein SIB is a block comprising styrene, butadiene, and isoprene as constituent monomers; PA is a block comprising butadiene or isoprene as a constituent monomer; X is the residue of at least one coupling agent; and n=2-4. Also provided is a process for preparing the copolymer rubber and use thereof.