Rubber Composition with Liquid Resin for Tire Dispersion
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Solution Overview
Problem
Current rubber compositions for tires face challenges in achieving balanced improvements in handling stability, fuel economy, wet grip performance, elongation at break, and abrasion resistance due to poor dispersibility of fine particle silica and sulfur, which affects uniform cross-linking and polymer distribution.
Innovation Solution
A rubber composition comprising diene rubber, silica with a specific BET surface area, sulfur, and a liquid resin with a specific softening point, particularly a coumarone-indene resin, which enhances dispersibility and cross-linking, improving handling stability, fuel economy, wet grip performance, and abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fine particle silica is added to improve grip performance and fuel economy, then fuel economy and wet grip performance are improved, but dispersibility deteriorates leading to reduced elongation at break
Solution Approach 1:
The patent uses a silane coupling agent as an intermediary substance that mediates between the fine particle silica and the rubber matrix. The silane coupling agent contains both hydrolyzable groups that bond to silica surface hydroxyl groups and organic groups that are compatible with the rubber polymer, thereby improving dispersibility without compromising fuel economy benefits
Solution Approach 2:
The patent controls the surface treatment parameters of fine particle silica by adjusting the silane coupling agent composition and treatment conditions. This modifies the surface properties of silica to reduce agglomeration tendency while maintaining the high surface area needed for fuel economy improvement
2Stability of the object's composition
If modified polymer with end modification for silica is used to improve dispersibility, then dispersibility is improved, but polymer bonds to silica before sufficient dispersion occurs
Solution Approach 1:
The patent applies preliminary surface treatment to the silica particles using silane coupling agents before mixing with the rubber matrix. This preliminary action creates a surface layer on silica that prevents premature bonding with the polymer, allowing uniform dispersion to occur first, and then enabling proper cross-linking during vulcanization
3Strength
If sulfur is added to achieve cross-linking, then cross-linking is achieved, but uniform dispersion in diene rubber deteriorates due to polarity mismatch
Solution Approach 1:
The patent employs organic sulfur compounds or sulfur donor compounds as intermediaries that facilitate cross-linking. These compounds have better compatibility with the non-polar diene rubber matrix compared to elemental sulfur, enabling uniform dispersion while still achieving effective cross-linking during vulcanization
4Stability of the object's composition
If sulfur-containing hybrid cross-linking agent is used to reduce S8 sulfur, then sulfur dispersibility is improved, but cost increases
Solution Approach 1:
The patent optimizes the composition and concentration of sulfur-containing hybrid cross-linking agents to achieve sufficient dispersibility and cross-linking at lower costs. By adjusting the molecular structure and dosage of the hybrid cross-linking agent, the patent balances performance requirements with cost effectiveness
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 composition achieves excellent handling stability, fuel economy, wet grip performance, elongation at break, and abrasion resistance while maintaining a balance between these properties by ensuring uniform dispersion and cross-linking of silica and sulfur within the rubber matrix.
Implementation Method 1
silica having a BET specific surface area measured in accordance with ASTM D3037-81 of 170 to 270 m²/g
Implementation Method 2
sulfur, and a liquid resin with a specific softening point
Implementation Method 3
a liquid resin with a specific softening point, particularly a coumarone-indene resin
Data Source
AI summary
The present invention provides a rubber composition for tires capable of improving handling stability, fuel economy, wet grip performance, elongation at break, and abrasion resistance together while maintaining the balance between them. The present invention also provides a pneumatic tire including the rubber composition. The present invention relates to a rubber composition for tires containing a diene rubber, silica having a BET specific surface area of 170 to 270 m2/g, sulfur, and a liquid resin having a softening point of -20 to 45°C, wherein the amount of the liquid resin is 0.5 to 20 parts by mass, and the amount of the silica is 40 to 120 parts by mass, each per 100 parts by mass of the rubber component of the rubber composition.