Tire Reinforcing Coating Rubber Composition for Heat-Aging Adhesion

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Solution Overview

Problem

Conventional rubber compositions for tire reinforcing members exhibit improved adhesion with increasing cobalt compound content, but this leads to decreased thermal degradation resistance.

Innovation Solution

A coating rubber composition comprising a rubber component with 60-100% isoprene skeleton rubber, carbon black with a specific DBP absorption number, and an amine-based antioxidant, along with a cobalt compound at optimal concentrations, to enhance adhesion and thermal degradation resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the content of the cobalt compound in the rubber composition increases, then the adhesion of the rubber composition to the reinforcing member improves, but the thermal degradation resistance of the rubber composition decreases

Engineering Contradiction:

Improveadhesion to reinforcing memberVSAvoidthermal degradation resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent optimizes the content parameter of the cobalt compound to a specific range (0.21-0.6 parts by mass per 100 parts by mass of rubber component) to achieve the best balance between adhesion improvement and thermal degradation resistance maintenance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite rubber composition system combining isoprene skeleton rubber (60-100 mass%), carbon black, cobalt compound, and amine-based antioxidant, where the synergistic interaction of components achieves both good adhesion and thermal degradation resistance

Inventive Principle:

Principle #40Composite materials

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 thermal degradation resistance and durability for tire reinforcing members, maintaining adhesion while improving thermal stability.

Implementation Method 1

the amine-based antioxidant is represented by the following general formula (1): [formula where R1 and R2 are each independently a monovalent saturated hydrocarbon group], and a content of the amine-based antioxidant is 0.1 parts by mass or more per 100 parts by mass of the rubber component

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

although the adhesion of a rubber composition to a reinforcing member improves as the content of the cobalt compound in the rubber composition increases

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS20250002744A1Coating rubber composition for tire reinforcing members, and tire

Publication Date: 2025.01.02 BRIDGESTONE CORP

AI summary

The present disclosure provides a coating rubber composition for tire reinforcing members having excellent thermal degradation resistance, including a rubber component, carbon black, a cobalt compound, and an amine-based antioxidant. The rubber component contains 60 to 100 mass % of an isoprene skeleton rubber. The content of the cobalt compound in cobalt equivalent is 0.21 parts by mass or more and 0.6 parts by mass or less per 100 parts by mass of the rubber component. The amine-based antioxidant is represented by the following general formula (1):where R1 and R2 are each independently a monovalent saturated hydrocarbon group. The content of the amine-based antioxidant is 0.1 parts by mass or more per 100 parts by mass of the rubber component.