Tire Rubber Composition for Low Heat and Ozone Aging Resistance

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Solution Overview

Problem

Existing tires face deterioration in performance due to hardening over time, which affects durability and fuel efficiency, particularly in the tread and sidewall parts, leading to increased rolling resistance and reduced overall tire performance.

Innovation Solution

The tire is composed of a tread part and sidewall part made of a rubber composition containing hydrogenated styrene-butadiene rubber, with specific ratios of styrene content, land ratio, and thickness to minimize heat generation and ozone deterioration, using recovered carbon black to reduce friction and enhance fuel efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a tire uses conventional rubber composition in tread and sidewall parts, then initial performance is acceptable, but durability and fuel efficiency deteriorate over time due to hardening effect

Engineering Contradiction:
ImprovedurabilityVSAvoidperformance consistency over time
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies different rubber compositions to different parts of the tire. The tread part uses a rubber composition with specific styrene content (15-30 mass%) and the sidewall part uses a different composition, allowing each part to be optimized for its specific function while resisting the hardening effect over time

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the chemical composition parameters of the rubber, specifically controlling the styrene content within 15-30 mass% and using specific ratios of rubber components. This parameter optimization prevents the hardening effect that occurs with conventional rubber compositions, maintaining durability and fuel efficiency throughout the tire's service life

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If a tire is designed for fuel efficiency with reduced rolling resistance, then fuel consumption improves, but durability may be compromised due to material limitations

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

Solution Approach 1:

The patent uses composite rubber compositions combining multiple rubber components with specific styrene content and ratios. This composite approach achieves low rolling resistance for fuel efficiency while maintaining the durability required for reliable tire performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By optimizing the styrene content parameter within 15-30 mass% and controlling the ratio of rubber components, the patent achieves a balance between fuel efficiency (low rolling resistance) and durability, allowing the tire to maintain both properties throughout its service life

Inventive Principle:
Principle #35Parameter changes

3Strength

If styrene content is increased to improve wear resistance, then tread durability improves, but heat generation increases reducing fuel efficiency

Engineering Contradiction:
Improvewear resistanceVSAvoidheat generation
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent optimizes the styrene content parameter within the range of 15-30 mass%, finding the optimal balance point where wear resistance is sufficient but heat generation is minimized. This parameter control prevents excessive heat buildup while maintaining adequate tread durability

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4588689A1tire
Publication Date: 2025.07.23 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4588689A1 patent drawingFigure 1
  • EP4588689A1 patent drawingFigure 2
  • EP4588689A1 patent drawingFigure 3

AI summary

A tire comprising a tread part (1) and a sidewall part (32), wherein the tread part and the sidewall part are each composed of a rubber composition comprising a rubber component comprising a hydrogenated styrene-butadiene rubber, and wherein L is 0.60 or more and 0.90 or less, and (St1 +St2)×T×L / 100 is 1.4 or less, where St1 represents a total styrene amount, in % by mass, of a rubber component constituting the tread part, St2 represents a total styrene amount, in % by mass, of a rubber component constituting the sidewall part, L represents a land ratio, and T represents a thickness, in mm, of a rubber layer constituting the sidewall part.