Tread Rubber Composition Balancing Block Chipping and Wear

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Solution Overview

Problem

Heavy-duty tires face challenges in achieving both excellent block chipping resistance and wear resistance, particularly in large-size vehicles like trucks and buses, where conventional tread designs fall short in providing sufficient durability and longevity.

Innovation Solution

A tread rubber composition comprising isoprene-based rubber, butadiene rubber, and styrene-butadiene rubber, combined with specific carbon black, is formulated to enhance hardness and elongation at break, resulting in improved block chipping and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional tread designs are used, then manufacturing cost and simplicity are maintained, but block chipping resistance and wear resistance are insufficient

Engineering Contradiction:
Improveblock chipping resistance and wear resistanceVSAvoidtread design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a composite rubber composition containing isoprene-based rubber, butadiene rubber, and styrene-butadiene rubber with specific carbon black (average particle diameter ≤20 nm or CTAB ≥130 m²/g). This composite material approach provides enhanced block chipping resistance and wear resistance through synergistic interactions between different rubber phases and carbon black reinforcement, resolving the contradiction between reliability improvement and design complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise compositional parameters: isoprene-based rubber 40-80 parts, butadiene rubber 10-50 parts, styrene-butadiene rubber 5-30 parts, and carbon black 20-60 parts per 100 parts rubber component. These controlled parameter changes optimize the balance between wear resistance, block chipping resistance, and elongation properties without requiring complex structural modifications.

Inventive Principle:
Principle #35Parameter changes

2Strength

If rubber composition is optimized for hardness, then wear resistance improves, but elongation at break deteriorates

Engineering Contradiction:
Improvewear resistanceVSAvoidelongation at break
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent controls the compositional parameters within specific ranges to achieve optimal balance: the rubber component composition and carbon black content are precisely regulated to provide both sufficient hardness for wear resistance and adequate elongation (EB ≥450%) for flexibility and crack resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The multi-phase rubber composite with carbon black reinforcement creates a synergistic structure where the carbon black network provides hardness and wear resistance, while the rubber phases maintain elasticity and elongation capability, resolving the contradiction between strength and compositional stability.

Inventive Principle:
Principle #40Composite materials

3Reliability

If carbon black particle size is reduced to enhance reinforcement, then processing difficulty and cost increase

Engineering Contradiction:
Improveblock chipping resistanceVSAvoidcarbon black dispersion and processing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies carbon black with average particle diameter not greater than 20 nm or CTAB not less than 130 m²/g, providing optimal reinforcement for block chipping resistance while maintaining manageable processing characteristics through controlled particle size and surface area parameters.

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 composition significantly enhances block chipping resistance and wear resistance by reinforcing the polymer network with styrene-butadiene rubber and dispersing carbon black at phase boundaries, inhibiting deformation, and ensuring good elongation, thereby improving tire durability.

Implementation Method 1

dispersing carbon black at phase boundaries

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

reinforcing the polymer network with styrene-butadiene rubber and dispersing carbon black

Methodology Applied
Scientific EffectReinforcement: Solid Solution Strengthening

Implementation Method 3

ensuring good elongation

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

dispersing carbon black at phase boundaries

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 5

improved block chipping and wear resistance

Methodology Applied
Scientific EffectWear resistance: Wear

Data Source

PatentEP4414183B1Tread rubber composition and tire
Publication Date: 2025.12.10 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4414183B1 patent drawingFigure 1
  • EP4414183B1 patent drawingFigure 2
  • EP4414183B1 patent drawingFigure 3

AI summary

A tread rubber composition and a tire that have excellent block chipping resistance and wear resistance are provided. The tread rubber composition contains a rubber component including an isoprene-based rubber, a butadiene rubber, and a styrene-butadiene rubber, and a carbon black having an average particle diameter not greater than 20 nm and/or a cetyltrimethylammonium bromide adsorption specific surface area not less than 130 m2/g, an amount of the isoprene-based rubber in 100% by mass of the rubber component is not less than 56% by mass, and the rubber composition satisfies hardness (Hs) ≥ 72 and elongation at break (EB) ≥ 420%.