Tire Tread Rubber Composition Silica Dispersion

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Solution Overview

Problem

Current tire tread rubber compositions fail to achieve optimal rolling resistance, wet grip performance, and wear resistance due to poor silica dispersion, and there is a need for improved processability and safety features in tire manufacturing.

Innovation Solution

A tire tread rubber composition is developed using a diene rubber with a modified conjugated diene polymer and a specific conjugated diene rubber, combined with silica and a silane coupling agent, along with an aromatic modified terpene resin, to enhance silica dispersibility and improve the tire's performance characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silica is simply blended with rubber component, then the blending process is simple, but the silica is not dispersed properly leading to insufficient rolling resistance reduction and wet grip performance

Engineering Contradiction:
Improvesilica dispersibilityVSAvoidcompound composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a silane coupling agent as an intermediary substance between silica and rubber component. The silane coupling agent has affinity with both silica and rubber, facilitating proper dispersion of silica in the rubber matrix. This mediator resolves the incompatibility between silica and rubber, enabling effective silica dispersion without over-complicating the compound composition.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite material system consisting of rubber component, silica, and silane coupling agent. This composite approach combines materials with different properties (elastomeric rubber, inorganic silica, and coupling silane) to achieve superior dispersion and performance characteristics that none of the individual components could provide alone.

Inventive Principle:
Principle #40Composite materials

2Reliability

If silica content is increased to improve wet grip performance, then wet grip performance is improved, but rolling resistance reduction becomes insufficient due to poor dispersion

Engineering Contradiction:
Improvewet grip performanceVSAvoidrolling resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The silane coupling agent serves as a mediator that enables high silica content to be effectively dispersed in the rubber. By improving the interfacial interaction between silica and rubber, the coupling agent allows the system to utilize the full potential of high silica loading for wet grip enhancement without suffering from aggregation-related rolling resistance penalties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional rubber composition is used, then the manufacturing process is straightforward, but processability and wear resistance performance are insufficient

Engineering Contradiction:
Improvewear resistance performanceVSAvoidprocessability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical parameters of the rubber compound by introducing silane coupling agent and optimizing the silica-rubber-silane system. These parameter changes (chemical composition, interfacial properties, dispersion state) lead to improved wear resistance while maintaining manufacturability through controlled compound formulation and processing.

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 achieves excellent processability, wet grip performance, and wear resistance, leading to improved rolling characteristics and safety features when formed into a pneumatic tire.

Implementation Method 1

silica exhibits low affinity with rubber components, and the cohesiveness between silica components themselves is high; therefore, if silica is simply blended with a rubber component, the silica is not dispersed

Methodology Applied
Scientific EffectSilane coupling: Chemical Bonding

Implementation Method 2

the silica is not dispersed, and this leads to a problem of not being able to sufficiently achieve the effect of reducing rolling resistance

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

the modified conjugated diene polymer being a modified conjugated diene polymer obtained by modifying an active terminal of a conjugated diene polymer having a content of cis-1,4-bonds of 75 mol% or greater, using at least a hydrocarbyloxysilane compound

Methodology Applied
Scientific EffectChemical modification: Chemical Bonding

Implementation Method 4

the specific conjugated diene rubber being a conjugated diene rubber obtained by bonding an active terminal of a conjugated diene polymer chain and a polyorganosiloxane

Methodology Applied
Scientific EffectTerminal bonding: Chemical Bonding

Implementation Method 5

an aromatic modified terpene resin having a softening point of from 60 to 150°C

Methodology Applied
Scientific EffectResin modification:

Data Source

PatentEP3572460B1Tire tread rubber composition and pneumatic tire
Publication Date: 2021.11.24 THE YOKOHAMA RUBBER CO LTD
  • EP3572460B1 patent drawingFigure 1
  • EP3572460B1 patent drawingFigure 2
  • EP3572460B1 patent drawingFigure 3

AI summary

The purpose of an embodiment of the present invention is to provide a tire tread rubber composition having excellent processability and offering excellent wet grip performance, rolling characteristics, and wear resistance performance when formed into a tire; and to provide a pneumatic tire in which the tire tread rubber composition is used. The tire tread rubber composition of an embodiment of the present invention contains a diene rubber, silica, a silane coupling agent, and an aromatic modified terpene resin having a softening point of from 60 to 150°C. The content of the silica is from 50 to 150 parts by mass per 100 parts by mass of the diene rubber, and the content of the silane coupling agent is from 2 to 20 mass% with respect to the content of the silica. The diene rubber contains a specific modified conjugated diene polymer and a specific conjugated diene rubber, the content of the modified conjugated diene polymer in the diene rubber is from 10 to 50 mass%, and the content of the specific conjugated diene rubber in the diene rubber is from 50 to 90 mass%.