Foam Sheet Structure for Residue-Free Display Panel Peeling

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Solution Overview

Problem

Conventional pressure-sensitive adhesive tapes struggle to be easily peeled off without leaving residue on display panels, especially in large televisions with high-quality OLED panels, due to issues with tensile strength and flexibility, whether using foams with low or high expansion ratios.

Innovation Solution

A foam sheet with specific tensile and breaking strengths, thickness, and density ranges, combined with a core layer and optional outer layers, allowing easy peeling by slicing without leaving adhesive residue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a foam with low expansion ratio is used as the base material, then the base material maintains structural integrity, but it cannot be torn in the plane direction and loses flexibility, making it impossible to use for fixing panels

Engineering Contradiction:
Improvetensile strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the tensile strength within 1-9 MPa and breaking strength at 3.5 MPa or less. This quantitative parameter optimization allows the foam to achieve the optimal balance between maintaining structural integrity and enabling easy tearing for slicing operations, directly resolving the contradiction between strength and flexibility.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a foam with high expansion ratio is used as the base material, then it can be torn in the plane direction, but the foam is pulled and torn or shredded during peeling due to low tensile strength

Engineering Contradiction:
ImprovetearabilityVSAvoidtensile strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent resolves this contradiction by establishing specific parameter ranges: tensile strength of 1-9 MPa and breaking strength of 3.5 MPa or less. These controlled parameters ensure the foam can be torn for slicing while maintaining sufficient tensile strength to prevent shredding during peeling operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structure with a foam base material layer and a surface layer (foam or resin film) laminated on the foam. This composite structure enhances the overall tensile strength and peeling resistance while maintaining the tearability needed for slicing.

Inventive Principle:
Principle #40Composite materials

3Length of stationary object

If the pressure-sensitive adhesive tape is made thin, then it meets the design requirements for thin televisions, but it becomes difficult to peel off without leaving adhesive residue

Engineering Contradiction:
ImprovethicknessVSAvoidpeelability
Core Design Contradiction:
Length of stationary objectVSEase of operation

Solution Approach 1:

The patent applies parameter changes by controlling the overall thickness within 0.05-0.9 mm while simultaneously optimizing the foam's tensile strength (1-9 MPa) and breaking strength (3.5 MPa or less). This multi-parameter optimization enables thin tape design that maintains excellent peelability through controlled slicing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies segmentation by introducing a cutting step that divides the tape into sections before peeling. This segmentation allows the thin tape to be peeled off in manageable sections without leaving residue, overcoming the peeling difficulty inherent in thin adhesive tapes.

Inventive Principle:
Principle #1Segmentation

4Length of stationary object

If the foam sheet is made thinner, then it meets the requirements for thin electronic devices, but it may lose the ability to provide adequate step followability

Engineering Contradiction:
ImprovethicknessVSAvoidstep followability
Core Design Contradiction:
Length of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent resolves this contradiction by optimizing multiple parameters simultaneously: thickness (0.05-0.9 mm), tensile strength (1-9 MPa), and breaking strength (3.5 MPa or less). This multi-parameter optimization ensures that even thin foam sheets maintain sufficient flexibility and step followability while meeting the thickness requirements for modern thin electronic devices.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4692187A1Foam sheet and adhesive tape
Publication Date: 2026.02.11 SEKISUI CHEMICAL CO LTD
  • EP4692187A1 patent drawingFigure 1~2
  • EP4692187A1 patent drawingFigure 3
  • EP4692187A1 patent drawing

AI summary

A foam sheet has a tensile strength of from 1 to 9 MPa and a breaking strength of 3.5 MPa or less when an interlaminar strength is measured, wherein the foam sheet does not break when an interlaminar strength is measured and has an overall thickness of from 0.05 to 0.9 mm.