Multilayer Pressure Sensitive Adhesive Sheet with Controlled Thickness Variation

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Solution Overview

Problem

Pressure sensitive adhesive sheets with multilayer structures often face issues with interlayer adhesion and film strength due to differences in materials between layers, leading to deteriorated performance.

Innovation Solution

A pressure sensitive adhesive sheet with a resin layer structured in a multilayer format, comprising layers (Xα), (Y1), and (Xβ) where the thickness variations of (Xα) and (Y1) are controlled to specific values, ensuring excellent interlayer adhesion and film strength by maintaining non-uniform thicknesses and incorporating different constitutional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pressure sensitive adhesive layer is formed as a multilayer structure with two or more layers to enhance adhesive capability and impart particular functions, then the pressure sensitive adhesive capability is improved, but the interlayer adhesion (interface strength) between the two layers is deteriorated

Engineering Contradiction:
Improvepressure sensitive adhesive capabilityVSAvoidinterlayer adhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a multilayer structure where each layer has specific local characteristics - the first layer (Xα) has pressure-sensitive adhesive properties with controlled thickness variation (3.00 μm or more difference between max and min), the second layer (Y1) has different constitutional components and larger thickness variation (5.00 μm or more), and the third layer (Xβ) provides additional functionality. This localized differentiation of properties within the multilayer structure enhances overall adhesive capability while maintaining interlayer adhesion through controlled thickness variations that prevent delamination.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining multiple layers with different constitutional components into a unified pressure sensitive adhesive layer. The first layer contains specific adhesive components, the second layer contains different components (as defined by the condition that at least one constitutional component differs from the first and third layers), and the third layer provides additional functionality. This composite structure achieves enhanced adhesive capability for specific applications while maintaining interlayer adhesion through controlled thickness variations and material compatibility.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a pressure sensitive adhesive layer is formed as a multilayer structure with two or more layers to enhance adhesive capability, then the pressure sensitive adhesive capability is improved, but the film strength of the pressure sensitive adhesive layer is deteriorated

Engineering Contradiction:
Improvepressure sensitive adhesive capabilityVSAvoidfilm strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a multilayer structure where each layer has specific local characteristics - the first layer (Xα) has pressure-sensitive adhesive properties with controlled thickness variation (3.00 μm or more difference between max and min), the second layer (Y1) has different constitutional components and larger thickness variation (5.00 μm or more), and the third layer (Xβ) provides additional functionality. This localized differentiation of properties within the multilayer structure enhances overall adhesive capability while maintaining interlayer adhesion through controlled thickness variations that prevent delamination.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining multiple layers with different constitutional components into a unified pressure sensitive adhesive layer. The first layer contains specific adhesive components, the second layer contains different components (as defined by the condition that at least one constitutional component differs from the first and third layers), and the third layer provides additional functionality. This composite structure achieves enhanced adhesive capability for specific applications while maintaining interlayer adhesion through controlled thickness variations and material compatibility.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If the thickness of each layer in the multilayer structure is made uniform, then the manufacturing precision is improved, but the interlayer adhesion and film strength are deteriorated

Engineering Contradiction:
Improvethickness uniformityVSAvoidinterlayer adhesion and film strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent applies parameter changes by intentionally controlling the thickness parameter of each layer to be non-uniform within specific ranges. The first layer (Xα) has a thickness difference between maximum and minimum values of 3.00 μm or more, and the second layer (Y1) has a thickness difference of 5.00 μm or more. These controlled parameter variations enhance interlayer adhesion and film strength by creating mechanical interlocking and stress distribution, while still maintaining manufacturing precision through defined tolerances and consistent constitutional composition within each layer.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3357979B1Adhesive sheet and method for producing adhesive sheet
Publication Date: 2024.11.20 LINTEC CORP
  • EP3357979B1 patent drawingFigure 1(a)~1(d)
  • EP3357979B1 patent drawingFigure 2~3
  • EP3357979B1 patent drawingFigure 4~5

AI summary

Provided is a pressure sensitive adhesive sheet including a resin layer that is a multilayer structure containing at least a layer (Xβ), a layer (Y1), and a layer (Xα) laminated in this order, a surface (α) of the layer (Xα) of the resin layer having pressure sensitive adhesiveness, at least a constitutional component contained in the layer (Y1) being different from constitutional components contained in the layer (Xα) and the layer (Xβ), on the prescribed cross section (P1) of the pressure sensitive adhesive sheet, in a range of 250 µm in a horizontal direction freely-selected, a difference between a maximum value and a minimum value of the layer (Xα) being 3.00 µm or more, and a difference between a maximum value and a minimum value of the layer (Y1) being 5.00 µm or more.