Tread Rubber Composition Using Fine Carbon Black for Block Durability

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Solution Overview

Problem

Heavy-duty tires face challenges in achieving excellent block chipping resistance and wear resistance, particularly in environmental and performance contexts, with existing rubber compositions and tread designs.

Innovation Solution

A tread rubber composition comprising isoprene-based rubber, butadiene rubber, styrene-butadiene rubber, and specific carbon black with predetermined properties, such as average particle diameter and cetyltrimethylammonium bromide adsorption specific surface area, which enhances hardness and elongation at break, resulting in improved block chipping and wear resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional rubber compositions are used in heavy-duty tires, then manufacturing cost and ease of manufacture are maintained, but block chipping resistance and wear resistance are insufficient

Engineering Contradiction:
Improveblock chipping resistanceVSAvoidrubber composition complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite rubber composition comprising four specific rubber components (natural rubber, isoprene rubber, butadiene rubber, and styrene-butadiene rubber) in optimized proportions. This multi-component composite system synergistically enhances block chipping resistance and wear resistance while maintaining manufacturability through established rubber processing techniques.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameter ranges for each rubber component (natural rubber: 20-40 parts, isoprene rubber: 30-50 parts, butadiene rubber: 10-30 parts, styrene-butadiene rubber: 5-20 parts per 100 parts of total rubber) to achieve the desired balance between block chipping resistance, wear resistance, and ease of manufacture within conventional processing parameters.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If rubber composition is optimized for block chipping resistance, then reliability improves, but wear resistance may be compromised

Engineering Contradiction:
Improveblock chipping resistanceVSAvoidwear resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent utilizes a four-component rubber composite where natural rubber provides tear strength and block chipping resistance, isoprene rubber enhances elasticity and wear resistance, butadiene rubber improves abrasion resistance, and styrene-butadiene rubber contributes to overall durability. The synergistic interaction of these components simultaneously optimizes both block chipping resistance and wear resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent assigns specific functional roles to different rubber components within the composite: natural rubber and isoprene rubber primarily contribute to block chipping resistance through their elastic properties, while butadiene rubber and styrene-butadiene rubber enhance wear resistance through their abrasion-resistant characteristics, creating a locally optimized composite structure.

Inventive Principle:
Principle #3Local quality

3Reliability

If tread pattern with multiple block types is used, then block chipping resistance improves, but device complexity increases

Engineering Contradiction:
Improveblock chipping resistanceVSAvoidtread pattern complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the tread portion into multiple land portions (crown land, intermediate land, shoulder land) with different block configurations. Each land portion contains blocks of specific sizes and arrangements optimized for its functional requirements, allowing the overall tread pattern to achieve superior block chipping resistance through segmented design rather than uniform complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements different block size distributions and configurations in different tread regions: larger blocks in the crown land for primary load bearing, intermediate blocks in the intermediate land for transition, and smaller blocks in the shoulder land for flexibility. This local optimization reduces overall device complexity while maintaining high reliability across the entire tread.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3738998B1Tread rubber composition and tire
Publication Date: 2024.08.21 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3738998B1 patent drawingFigure 1
  • EP3738998B1 patent drawingFigure 2
  • EP3738998B1 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%.