Laminated Product Adhesion Layer Shrinkage Control

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Solution Overview

Problem

Conventional laminated products with metal and resin bodies face challenges in maintaining strong joining strength due to thermal expansion differences, leading to stress absorption by adhesives, which limits durability.

Innovation Solution

Incorporating a thermoplastic resin or thermoplastic elastomer adhesion layer with controlled molding shrinkage not higher than 1.5% between the metal and resin bodies, enhancing stress absorption and adhesion strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal body and a resin body are joined together via an adhesive, then the laminated product can be formed, but the joining strength is insufficient due to thermal expansion differences causing stress on the adhesive

Engineering Contradiction:
Improvejoining strengthVSAvoiddurability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameters of the adhesion layer by selecting thermoplastic resins or thermoplastic elastomers with specific molding shrinkage characteristics (not higher than 1.5%). This parameter optimization allows the adhesion layer to better accommodate thermal expansion differences between metal and resin bodies, reducing stress concentration and improving both joining strength and durability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite adhesion layer structure combining thermoplastic resins or thermoplastic elastomers with controlled molding shrinkage. This composite material approach creates an intermediate layer that bridges the metal and resin bodies, providing both mechanical adhesion and thermal stress buffering, thereby enhancing the overall joining performance and reliability.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If the adhesion layer has high molding shrinkage, then the adhesion layer can be easily formed, but the joining strength between metal and resin bodies decreases due to increased thermal shrinkage stress

Engineering Contradiction:
Improveadhesion layer formationVSAvoidjoining strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent optimizes the molding shrinkage parameter of the adhesion layer to be not higher than 1.5%, finding the optimal balance between manufacturability and joining strength. This controlled shrinkage rate allows sufficient material flow during molding while minimizing thermal shrinkage stress that would compromise the joining strength between metal and resin bodies.

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 solution effectively improves the joining strength between metal and resin bodies, enhancing the durability of laminated products, such as airless tires, by reducing thermal shrinkage-induced stress and maintaining cohesive strength.

Implementation Method 1

a metal body and a resin body have different coefficients of thermal expansion. Thus, if the metal body and the resin body experience thermal shrinkage or the like, a stress is applied to a cured product of the adhesive therebetween

Methodology Applied
Scientific EffectThermal shrinkage: Thermal Contraction

Implementation Method 2

the adhesion layer has a molding shrinkage not higher than 1.5%

Methodology Applied
Scientific EffectMolding shrinkage:

Implementation Method 3

an adhesion layer disposed between the metal body and the resin body, and containing a thermoplastic resin or a thermoplastic elastomer

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4212353A1Laminated product, airless tire and manufacturing method therefor
Publication Date: 2023.07.19 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4212353A1 patent drawingFigure 1
  • EP4212353A1 patent drawingFigure 2(a)~2(c)
  • EP4212353A1 patent drawingFigure 3

AI summary

Provided is a laminated product in which the joining strength between a metal body and a resin body can be improved. The laminated product is a laminated product 1 in which a metal body 2 and a resin body 3 are joined together. The laminated product 1 includes: the metal body 2; the resin body 3; and an adhesion layer 4 disposed between the metal body 2 and the resin body 3, and containing a thermoplastic resin or a thermoplastic elastomer. The adhesion layer 4 has a molding shrinkage not higher than 1.5%.