Elastomer Laminate Intermediate Layer Adhesion

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Solution Overview

Problem

The adhesion between weakly unsaturated diene rubber compositions used in tire treads and highly unsaturated natural rubber underlayers is insufficient, leading to potential separation issues in tire applications.

Innovation Solution

A diene rubber composition with a diene unit mass ratio greater than 50% is used as an intermediate layer between the tread and underlayer, enhancing the laminate's resistance to separation by acting as a bonding gum, thereby improving the adhesion between the two compositions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a weakly unsaturated elastomeric matrix (less than 10% diene unit) is used in the tread composition, then the tread exhibits good wear resistance and stability, but the adhesion to the underlayment becomes insufficient

Engineering Contradiction:

Improveadhesion between tread and underlaymentVSAvoidseparation resistance during tire lifespan

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent introduces an intermediate layer with high diene unit content (greater than 50% by mass) between the weakly unsaturated tread composition and the highly unsaturated natural rubber underlayment. This intermediate layer acts as a mediator that provides sufficient adhesion to both layers, with the diene units forming crosslinks with the underlayment while the ethylene units provide compatibility with the tread composition.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the diene unit content parameter of the intermediate layer to be greater than 50% by mass, which is significantly higher than the weakly unsaturated tread (less than 10%) and the highly unsaturated natural rubber underlayment. This parameter change enables the intermediate layer to provide sufficient adhesion points through crosslinking while maintaining compatibility with both adjacent layers.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If a highly unsaturated natural rubber is used in the underlayment, then the underlayment provides good flexibility and adhesion potential, but the adhesion to weakly unsaturated tread compositions is insufficient

Engineering Contradiction:

Improveflexibility of underlaymentVSAvoidadhesion to tread

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The intermediate layer with high diene unit content serves as a mediator between the highly unsaturated natural rubber underlayment and the weakly unsaturated tread. The intermediate layer's high diene content allows it to form strong crosslinks with the underlayment, while its composition provides compatibility with the tread, thereby transmitting the adhesion benefit of high unsaturation to the underlayment without compromising tread adhesion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If no intermediate bonding layer is used between tread and underlayment, then the structure is simpler, but the adhesion between layers is insufficient leading to separation

Engineering Contradiction:

Improvenumber of layers in laminateVSAvoidbonding strength between compositions

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The patent introduces an intermediate layer as a mediator to achieve sufficient bonding strength between the tread and underlayment. This intermediate layer with high diene unit content provides the necessary adhesion points through crosslinking, resolving the adhesion insufficiency problem that would otherwise require a much thicker or more complex bonding layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite laminate structure with three distinct layers, each having specific compositional characteristics. The intermediate layer with high diene unit content (greater than 50%) forms a composite material that bridges the weakly unsaturated tread and highly unsaturated underlayment, providing both adhesion and structural integrity.

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 use of a diene rubber composition with a high diene unit mass ratio as an intermediate layer significantly improves the adhesion between the tread and underlayer, enhancing the laminate's resistance to separation and ensuring durability throughout the tire's lifespan.

Implementation Method 1

The underlayer generally adheres to the tread through physical or chemical phenomena, such as the phenomena of interpenetration, entanglement or crosslinking of the diene rubber compositions constituting respectively the tread and the underlayment to the tread.

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentEP3227106B1Elastomer laminate comprising three layers

Publication Date: 2019.01.02 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

The invention relates to an elastomer laminate comprising three layers, the first layer consisting of a diene rubber composition comprising a first elastomer matrix; the second layer consisting of a diene rubber composition comprising a second elastomer matrix, which second elastomer matrix comprises a second elastomer comprising ethylene units and diene units comprising a carbon-carbon double bond, the units being statistically distributed within the second elastomer; the third layer consisting of a diene rubber composition comprising a third diene elastomer with a diene unit mass rate greater than 50%, the second layer being disposed between the first layer and the third layer. A laminate of this type has good resistance to separation of its constituent layers.