Rubber Composition Balancing Low Tg and Tread Rigidity

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Solution Overview

Problem

Existing rubber compositions for tire treads face a challenge in balancing glass transition temperature and rigidity, as reducing glass transition temperature to improve grip in cold weather leads to reduced rigidity and increased tread wear.

Innovation Solution

A rubber composition comprising a highly saturated diene elastomer copolymer of ethylene and 1,3-butadiene, combined with carbon black and a specific aliphatic diacid dialkyl ester plasticizer, such as diisooctyl sebacate, to maintain rigidity while lowering glass transition temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an oil with a low glass transition temperature is added to reduce the glass transition of the mixture, then the grip in cold weather is improved, but the rigidity of the mixture is reduced and tread wear increases

Engineering Contradiction:

Improveglass transition temperatureVSAvoidrigidity

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters by replacing conventional oil plasticizers with a specific aliphatic diacid dialkyl ester plasticizer having controlled molecular structure (specific chain length and branching), thereby achieving lower glass transition temperature while preserving rigidity through optimized molecular parameters

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite plasticizer system combining aliphatic diacid dialkyl ester with the highly saturated diene elastomer matrix, where the specific interaction between the plasticizer molecules and polymer chains achieves both temperature reduction and rigidity maintenance through synergistic material composition

Inventive Principle:

Principle #40Composite materials

2Reliability

If the glass transition temperature is reduced to improve grip in cold weather, then the tire grip is improved, but the tread wear increases due to reduced rigidity

Engineering Contradiction:

Improvetire gripVSAvoidtread wear

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the plasticizer molecular parameters (chain length, branching structure) to achieve optimal balance between glass transition temperature reduction for grip improvement and rigidity preservation for wear resistance, thereby simultaneously improving reliability and extending service life

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of reduced rigidity (which would increase wear) into a benefit by selecting a plasticizer that maintains adequate rigidity while achieving the desired glass transition temperature reduction, thus improving grip without the intended negative consequence of increased wear

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4267672B1Rubber composition comprising a highly saturated diene elastomer

Publication Date: 2025.01.22 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

The present invention relates to a rubber composition based on at least one elastomer matrix mainly comprising a highly saturated diene elastomer, carbon black, and an aliphatic diacid dialkyl ester, wherein the highly saturated diene elastomer is a copolymer of ethylene and a 1,3-diene, in which the ethylene units represent at least 50 mol % of the monomer units of the copolymer.