α-Methylstyrene Elastomer Matrix for Lower Hysteresis Loss

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Solution Overview

Problem

Existing thermoplastic elastomers with poly(α-methylstyrene) blocks face challenges in reducing hysteresis, which affects rolling resistance and overall performance in applications such as tyres and other hysteretic materials.

Innovation Solution

A combination of a triblock thermoplastic elastomer with a central diene elastomer block and two terminal α-methylstyrene blocks, along with specific proportions of diblock and thermoplastic polymer containing α-methylstyrene units, is used to create an elastomer matrix that significantly reduces hysteresis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermoplastic elastomers with poly(α-methylstyrene) blocks are used to achieve high thermal strength, then the material exhibits high Tg and rigid thermoplastic blocks, but the hysteresis losses increase which worsens rolling resistance performance

Engineering Contradiction:
Improveglass transition temperature (Tg)VSAvoidhysteresis losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The invention changes the chemical composition parameters of the thermoplastic blocks by incorporating cyclicly aliphatic hydrocarbon units (C10-C20) alongside α-methylstyrene units. This compositional parameter change modifies the Tg and hysteresis characteristics, achieving a balance between thermal strength and energy loss reduction

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite thermoplastic block structure combining different types of hydrocarbon units (cyclicly aliphatic C10-C20 and α-methylstyrene) within the same polymer block. This composite approach allows synergistic effects where the cyclic structures reduce hysteresis while the α-methylstyrene maintains thermal strength

Inventive Principle:
Principle #40Composite materials

2Strength

If the content of thermoplastic chains comprising α-methylstyrene units is increased to improve thermal properties, then the rigid nodules provide better crosslinking behavior, but the material may become too rigid and lose elastomeric properties

Engineering Contradiction:
Improvemechanical strengthVSAvoidelastomeric properties
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention applies local quality by creating distinct regions within the thermoplastic blocks - the cyclicly aliphatic hydrocarbon units (C10-C20) provide flexible, elastomeric character while the α-methylstyrene units provide rigid, thermoplastic character. This local differentiation allows the material to exhibit both strength and elastomeric behavior

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention optimizes the ratio parameters of different hydrocarbon units in the thermoplastic blocks, specifically maintaining cyclicly aliphatic C10-C20 units at 5-50 mol% and α-methylstyrene units at 50-95 mol%. This parameter optimization ensures the material retains sufficient elastomeric properties while achieving desired mechanical strength

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 elastomer matrix achieves a substantial decrease in hysteresis, improving performance and rolling resistance while maintaining elastomeric properties, with optimal proportions of thermoplastic components between 10% to 55% by weight.

Implementation Method 1

the association of the rigid thermoplastic blocks with one another gives the material the behaviour of a crosslinked elastomer. This is because the rigid nodules, formed by the zones of associations of thermoplastic blocks with one another, play the role of crosslinking node

Methodology Applied
Scientific EffectCrosslinking:

Implementation Method 2

An ongoing objective of tyre manufacturers is the reduction in the rolling resistance. The improvement of the rolling resistance presupposes lowering the hysteresis losses

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Data Source

PatentUS20250270401A1Elastomer matrix comprising a thermoplastic elastomer
Publication Date: 2025.08.28 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

An elastomer matrix comprises: a triblock thermoplastic elastomer having a central diene elastomer block and two terminal thermoplastic blocks comprising a-methylstyrene units bonded to the diene elastomer block; from 2% to 20% by weight of a diblock thermoplastic elastomer having a diene elastomer block and a thermoplastic block comprising α-methylstyrene units; and more than 10% by weight of a thermoplastic polymer comprising α-methylstyrene units. The content of thermoplastic blocks is at least 10% by weight, with respect to the total weight of the triblock and diblock thermoplastic elastomers, the content of thermoplastic chains comprising a-methylstyrene units is at most 55% by weight, with respect to the total weight of the elastomer matrix, and the thermoplastic chains comprising α-methylstyrene units are constituted of the chains of the thermoplastic polymer comprising α-methylstyrene units and of the thermoplastic blocks of the triblock and diblock thermoplastic elastomers.