Halogenated Polyisoprene Rubber Composition for Tire Crack Growth Resistance

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Solution Overview

Problem

Existing tire rubber compositions lack sufficient improvement in crack growth resistance and compression set performance.

Innovation Solution

A rubber composition that satisfies the relationship 0.42 ≤ Fw / Fa < 1.00, where Fa and Fw are averages of stresses detected in atmospheric air and water at 23°C using an atomic force microscope, indicating reversible bonding and hardness changes, enhancing crack growth resistance and compression set through the use of specific chemical blends and fillers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional diene rubbers and fillers are used in tire rubber compositions, then basic tire performance is maintained, but crack growth resistance and compression set performance are insufficient

Engineering Contradiction:

Improvecrack growth resistanceVSAvoidcompression set

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention changes the chemical composition parameters of the rubber blend by incorporating specific ratios of halogenated polyisoprene rubber (0.1-10 parts by mass per 100 parts by mass of total rubber) along with sulfur and metal oxide. This parameter change in composition enables simultaneous improvement of crack growth resistance and compression set properties that conventional diene rubbers cannot achieve alone.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite rubber material system combining halogenated polyisoprene rubber with sulfur and metal oxide components. This composite formulation produces a vulcanized rubber composition where the interaction between halogenated rubber, sulfur crosslinks, and metal oxide fillers synergistically improves both crack growth resistance and compression set performance beyond what single conventional rubbers can provide.

Inventive Principle:

Principle #40Composite materials

2Reliability

If existing rubber compositions are used, then manufacturing simplicity is maintained, but overall performance in crack growth resistance and compression set is insufficient

Engineering Contradiction:

Improveoverall performanceVSAvoidcomposition complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention specifies precise compositional parameters (halogenated polyisoprene rubber at 0.1-10 parts by mass per 100 parts by mass of total rubber, specific sulfur and metal oxide ratios) that can be directly implemented in manufacturing. These parameter specifications provide clear production guidelines that balance performance improvement with manufacturing feasibility, avoiding overly complex formulations.

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 rubber composition achieves improved overall performance in crack growth resistance and compression set by leveraging reversible bonds and chemical properties, providing enhanced resilience and strain recovery.

Implementation Method 1

Fa and Fw denote averages of stresses detected in atmospheric air at 23°C and water, respectively, using an atomic force microscope

Methodology Applied

Scientific EffectAtomic force microscopy: Scanning Probe Microscopy

Data Source

PatentEP4174132A1Rubber composition and tire

Publication Date: 2023.05.03 SUMITOMO RUBBER INDUSTRIES LTD

AI summary

Provided are a rubber composition and a tire which provide improved overall performance in terms of crack growth resistance and compression set. Included is a rubber composition which satisfies the following relationship (1): (1) 0.42 ≤ Fw/Fa < 1.00 wherein Fa and Fw denote the averages of stresses detected in atmospheric air at 23°C and water, respectively, using an atomic force microscope.