Rubber Composition for Tire Tread Using Hydrogenated SBR
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Solution Overview
Problem
Conventional rubber compositions for tire tread struggle to balance steering stability, wear resistance, and fracture properties, with methods to enhance hysteresis loss either failing to provide sufficient compatibility or compromising fracture properties.
Innovation Solution
A rubber composition comprising an aromatic vinyl compound-conjugated diene compound copolymer and a hydrogenated styrene-butadiene copolymer, with specific molecular weights and bound styrene content, is used to improve steering stability and wear resistance without compromising fracture properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid polymer with low molecular weight is used to increase hysteresis loss, then steering stability is improved, but the polymer crosslinks with matrix rubber reducing compatibility and sufficient hysteresis loss
Solution Approach 1:
The patent changes the molecular weight parameter of the liquid polymer to a specific range (5,000-50,000) and controls the hydrogenation ratio of double bonds (20-60%) to optimize both compatibility and hysteresis loss properties
Solution Approach 2:
The patent creates a composite rubber composition by combining liquid polymer with specific properties (controlled molecular weight and partial hydrogenation) with matrix rubber, achieving synergistic effects that resolve the contradiction between compatibility and hysteresis loss
2Stability of the object's composition
If hydrogenation ratio of double bonds in liquid polymer is increased to prevent crosslinking, then compatibility is improved, but fracture properties deteriorate
Solution Approach 1:
The patent optimizes the hydrogenation ratio parameter to a specific range (20-60%) rather than complete hydrogenation, maintaining enough double bonds for fracture resistance while achieving sufficient compatibility
3Reliability
If hysteresis loss is increased to improve steering stability, then steering stability is improved, but wear resistance and fracture properties are compromised
Solution Approach 1:
The patent develops a composite rubber composition using liquid polymer with controlled molecular weight (5,000-50,000) and partial hydrogenation (20-60%), achieving high hysteresis loss while maintaining wear resistance and fracture properties through optimized material composition
Solution Approach 2:
The patent changes multiple parameters including molecular weight range, hydrogenation ratio, and polymer content (5-50 parts by mass per 100 parts matrix rubber) to simultaneously achieve high hysteresis loss and maintain other critical properties
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 rubber composition achieves high hysteresis loss, excellent wear resistance, and maintained fracture properties, enhancing the overall performance of tires by improving steering stability and wear resistance while ensuring safety and economical efficiency.
Implementation Method 1
it is known that a loss characteristic above room temperature (tan δ) is an important indicator for developing the rubber composition for the steering stability of the tire. In order to improve the steering stability of the tire, it is effective to increase a hysteresis loss above room temperature of the rubber composition used as the tread rubber
Implementation Method 2
the amount of double bonds having a crosslinking property is large, and thus, a part of the liquid polymer is incorporated into a matrix rubber by crosslinking with the matrix
Implementation Method 3
a method to increase hysteresis loss of the rubber composition is proposed wherein the double bond in the liquid polymer is saturated by hydrogenation
Data Source
AI summary
A rubber composition comprises as a rubber component (A) an aromatic vinyl compound-conjugated diene compound copolymer polymerized with a lithium-based polymerization initiator and having a polystyrene-conversion weight average molecular weight of 3.0×105−3.0×106 as measured by a gel permeation chromatography and (B) 10-200 parts by mass, based on 100 parts by mass of the copolymer (A), of a hydrogenated styrene-butadiene copolymer having a polystyrene-conversion weight average molecular weight of 5.0×103−2.0×105 as measured by a gel permeation chromatography and a bound styrene content of 10-70 mass % in which 25-50% of double bonds in butadiene portion is hydrogenated.