Tread Rubber Composition for Fuel-Efficient Wear-Resistant Tires

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Solution Overview

Problem

The challenge is to develop a tire that balances fuel economy, abrasion resistance, and handling stability while minimizing the use of carbon black and silica, as reducing these fillers compromises the strength and rigidity of the tread rubber.

Innovation Solution

A tire with a tread rubber composition comprising isoprene-based rubber, polybutadiene rubber, and styrene-butadiene rubber, where the isoprene-based rubber content exceeds both polybutadiene and styrene-butadiene rubber content, and silica content is equal to or greater than carbon black content, ensuring specific tan δ and negative ratio values to enhance performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the amount of carbon black or silica as filler is reduced to improve fuel economy, then fuel economy is improved, but the strength of the tread rubber is reduced, resulting in deteriorated chipping resistance and abrasion resistance

Engineering Contradiction:
Improvefuel economyVSAvoidtread rubber strength
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The patent applies parameter changes by establishing specific quantitative relationships between rubber components and fillers. Relationship (1) requires isoprene-based rubber content to exceed styrene-butadiene rubber content, relationship (2) requires isoprene-based rubber content to exceed polybutadiene rubber content, and relationship (3) requires silica content to be greater than or equal to carbon black content. These parameter constraints optimize the balance between fuel economy and tread strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple rubber components (isoprene-based rubber, polybutadiene rubber, styrene-butadiene rubber) with fillers (silica and carbon black) in specific proportions. This composite approach allows the tread rubber to achieve both reduced filler content for fuel economy and maintained strength through optimized material composition

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If the amount of carbon black or silica as filler is reduced to improve fuel economy, then fuel economy is improved, but abrasion resistance is reduced

Engineering Contradiction:
Improvefuel economyVSAvoidabrasion resistance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by establishing specific quantitative relationships between rubber components and fillers. Relationship (1) requires isoprene-based rubber content to exceed styrene-butadiene rubber content, relationship (2) requires isoprene-based rubber content to exceed polybutadiene rubber content, and relationship (3) requires silica content to be greater than or equal to carbon black content. These parameter constraints optimize the balance between fuel economy and abrasion resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple rubber components (isoprene-based rubber, polybutadiene rubber, styrene-butadiene rubber) with fillers (silica and carbon black) in specific proportions. This composite approach allows the tread rubber to achieve both reduced filler content for fuel economy and maintained abrasion resistance through optimized material composition

Inventive Principle:
Principle #40Composite materials

3Use of energy by moving object

If the amount of carbon black or silica as filler is reduced to improve fuel economy, then fuel economy is improved, but the rigidity of the tread portion is reduced, resulting in deteriorated handling stability

Engineering Contradiction:
Improvefuel economyVSAvoidhandling stability
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by establishing specific quantitative relationships between rubber components and fillers. Relationship (1) requires isoprene-based rubber content to exceed styrene-butadiene rubber content, relationship (2) requires isoprene-based rubber content to exceed polybutadiene rubber content, and relationship (3) requires silica content to be greater than or equal to carbon black content. These parameter constraints optimize the balance between fuel economy and handling stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining multiple rubber components (isoprene-based rubber, polybutadiene rubber, styrene-butadiene rubber) with fillers (silica and carbon black) in specific proportions. This composite approach allows the tread rubber to achieve both reduced filler content for fuel economy and maintained rigidity for handling stability through optimized material composition

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4074520B1tire
Publication Date: 2023.08.23 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4074520B1 patent drawingFigure 1
  • EP4074520B1 patent drawingFigure 2
  • EP4074520B1 patent drawing

AI summary

Provided is a tire that provides improved overall performance in terms of fuel economy, abrasion resistance, and handling stability. Included is a tire which includes a tread including a rubber composition, the rubber composition containing rubber components including an isoprene-based rubber, a polybutadiene rubber, and a styrene-butadiene rubber, and fillers including silica and carbon black, the rubber composition satisfying the following relationships (1) to (3): (1) Isoprene-based rubber content > Styrene-butadiene rubber content; (2) Isoprene-based rubber content > Polybutadiene rubber content; and (3) Silica content ≥ Carbon black content, the tire satisfying the following relationships (4) and (5) with respect to the tan δ at 30°C of the rubber composition and the negative ratio N (%) of the tread: (4) tan δ at 30°C < 0.10; and (5) tan δ at 30°C x N < 4.0.