Cap Tread Composition Balancing Fuel Economy and Abrasion

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Solution Overview

Problem

Existing tires face challenges in achieving a well-balanced improvement in fuel economy and abrasion resistance, as these performance metrics are generally contradictory.

Innovation Solution

A tire design featuring a cap tread with a styrene-butadiene rubber component and sulfur, where the styrene content is 20% by mass or lower, and the sulfur content is between 0.5 to 1.5 parts by mass per 100 parts by mass of the rubber component, with a cap tread thickness of less than 10.5 mm and a specific ratio of SWELL to (sulfur content times tread thickness) of 21 or higher.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the cap tread thickness is reduced to improve fuel economy, then fuel economy is improved, but abrasion resistance deteriorates

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

Solution Approach 1:

The patent applies parameter changes by precisely controlling the sulfur content (0.5-1.5 parts by mass per 100 parts by mass of rubber component) and styrene-butadiene rubber content (5-100% by mass) to achieve optimal cross-linking density. This allows the cap tread to maintain high abrasion resistance even with reduced thickness, thereby improving fuel economy without sacrificing durability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining styrene-butadiene rubber with specific sulfur content to create a cap tread composition that achieves both low rolling resistance (improving fuel economy) and high abrasion resistance. The specific formulation creates a composite structure that balances these contradictory properties

Inventive Principle:
Principle #40Composite materials

2Reliability

If the sulfur content is increased to improve abrasion resistance, then abrasion resistance is improved, but fuel economy deteriorates

Engineering Contradiction:
Improveabrasion resistanceVSAvoidfuel economy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the sulfur content to a specific range (0.5-1.5 parts by mass per 100 parts by mass of rubber component). This precise parameter control achieves the optimal cross-linking density that simultaneously provides high abrasion resistance and low rolling resistance, thereby improving both durability and fuel economy

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the styrene content is increased to improve abrasion resistance, then abrasion resistance is improved, but fuel economy deteriorates

Engineering Contradiction:
Improveabrasion resistanceVSAvoidfuel economy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by controlling the styrene content in styrene-butadiene rubber to 20% by mass or lower. This parameter optimization reduces the glass transition temperature and improves the elastic properties of the rubber, thereby reducing rolling resistance and improving fuel economy while maintaining adequate abrasion resistance through the optimized sulfur cross-linking system

Inventive Principle:
Principle #35Parameter changes

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 tire achieves excellent overall performance in terms of both fuel economy and abrasion resistance, effectively addressing the balance between these two contradictory metrics.

Implementation Method 1

a cap tread containing a rubber component and sulfur, the cap tread containing a styrene-butadiene rubber

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Data Source

PatentEP4566837A1tire
Publication Date: 2025.06.11 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4566837A1 patent drawingFigure 1
  • EP4566837A1 patent drawingFigure 2
  • EP4566837A1 patent drawing

AI summary

Provided is a tire having excellent overall performance in terms of fuel economy and abrasion resistance. The tire includes a cap tread containing a rubber component and sulfur, the cap tread containing a styrene-butadiene rubber having a styrene content of 20% by mass or lower in an amount Lc of 5% by mass or more and 100% by mass or less based on 100% by mass of the rubber component and the sulfur in an amount Sc of 0.5 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the rubber component, the cap tread having a thickness T of less than 10.5 mm, the cap tread having a ratio (SWELL/(Sc × T)) of SWELL (%) of the cap tread to a value of "the amount Sc (parts by mass) of the sulfur per 100 parts by mass of the rubber component × the thickness T (mm) of the cap tread" of 21 or higher.