Fabric-Backed PSA Sheet Structure for High Peel Strength

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Solution Overview

Problem

Existing PSA sheets laminated on fabric sheets, such as nonwoven fabrics, face challenges in achieving high peel strength to adherends.

Innovation Solution

A PSA sheet comprising a fabric sheet with specific thickness and bulk density, laminated with a PSA layer containing a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound, and a tackifier resin with varying softening points, enhances peel strength by reinforcing the fabric sheet and preventing rupture-peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a PSA layer is laminated on a conventional fabric sheet, then the PSA sheet can be manufactured, but the peel strength to adherends is insufficient

Engineering Contradiction:
Improvepeel strengthVSAvoidadhesion performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the physical parameters of the fabric sheet, specifically controlling thickness to 15-50 μm and bulk density to 0.35 g/cm³ or higher. These parameter modifications optimize the fabric's mechanical properties to prevent rupture during peeling while maintaining structural integrity, thereby achieving peel strength of 4 N/20mm or greater to stainless steel plates.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure consisting of a PSA layer combined with a specifically engineered fabric sheet. This composite material integrates the adhesive properties of the PSA with the mechanical reinforcement of the optimized fabric, resulting in enhanced overall performance that neither component could achieve alone.

Inventive Principle:
Principle #40Composite materials

2Strength

If the fabric sheet thickness is increased to prevent rupture, then structural integrity is improved, but the flexibility and conformability to adherends deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent optimizes the fabric sheet thickness parameter to a specific range of 15-50 μm. This controlled thickness provides sufficient structural integrity to prevent rupture during application and peeling, while simultaneously maintaining adequate flexibility to conform to various adherend surfaces. The bulk density parameter is also controlled at 0.35 g/cm³ or higher to enhance mechanical strength without excessive thickening.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If a tackifier resin with high softening point is used, then heat resistance is improved, but the initial tack and adhesion at room temperature deteriorates

Engineering Contradiction:
Improveheat resistanceVSAvoidinitial tack
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent carefully controls the softening point parameter of the tackifier resin within the range of 80-150°C. This optimized parameter range ensures that the resin maintains appropriate softness at room temperature for good initial tack and adhesion, while providing sufficient heat resistance for practical applications. The base polymer and tackifier resin are also balanced in specific proportions to achieve this compromise.

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 PSA sheet achieves a 180° peel strength of 4 N/20mm or greater to stainless steel plates, suitable for bonding and fixing parts, by optimizing the fabric sheet's properties and incorporating a tailored tackifier resin composition.

Implementation Method 1

pressure-sensitive adhesive (PSA) exists as a soft solid (a viscoelastic material) in a room temperature range and has a property to adhere easily to an adherend with some pressure applied

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a polymer that shows rubberlike elasticity at room temperature as the base polymer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

reinforcing the fabric sheet and preventing rupture-peeling

Methodology Applied
Scientific EffectMechanical reinforcement: Mechanical Force

Data Source

PatentEP3936335B1Pressure-sensitive adhesive sheet
Publication Date: 2026.01.07 NITTO DENKO CORP
  • EP3936335B1 patent drawingFigure 1
  • EP3936335B1 patent drawing

AI summary

Provided is a PSA sheet comprising a fabric sheet and a PSA layer laminated on the fabric sheet. The PSA layer comprises a base polymer and a tackifier resin. The base polymer is a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound. The tackifier resin comprises a tackifier resin having a softening point below 120 °C and a tackifier resin having a softening point of 120 °C or higher. The fabric sheet has a thickness of 15 µm or greater and 50 µm or less as well as a bulk density of 0.25 g/cm3 or higher and 0.50 g/cm3 or lower.