Polyester Pressure-Sensitive Adhesive for Surface Protection

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Solution Overview

Problem

Current pressure-sensitive adhesive sheets for surface protection, such as those used on electronic devices, face challenges with high costs, poor wettability, and staining issues due to the use of silicone-based and acryl-based adhesives, and require environmentally friendly alternatives that are cost-effective and provide good peelability and anti-staining properties.

Innovation Solution

A polyester-based pressure-sensitive adhesive composition is developed using plant-derived raw materials, comprising a polyester obtained by condensation polymerization of a dicarboxylic acid and a tricarboxylic acid with a specific weight ratio, combined with a diol component and a crosslinking agent, which forms a pressure-sensitive adhesive sheet with excellent wettability, light peelability, and anti-staining properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silicone-based pressure-sensitive adhesive is used, then wettability to adherend is improved, but cost increases

Engineering Contradiction:
ImprovewettabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by using polyester-based adhesive with specific molecular weight (5000-150000) and controlled hydroxyl value (5-50 mg KOH/g) to achieve good wettability without relying on expensive silicone-based materials. This parameter optimization allows the adhesive to spread properly on display surfaces while maintaining cost-effectiveness.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If acryl-based pressure-sensitive adhesive is used, then cost is reduced, but plasticizer bleeding and staining occur

Engineering Contradiction:
ImprovecostVSAvoidstaining
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent replaces expensive silicone-based adhesives with cost-effective polyester-based adhesives that do not require plasticizers, thereby eliminating the staining problem associated with acryl-based adhesives while maintaining affordability. The polyester composition provides inherent stability without harmful bleeding components.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite polyester-based adhesive system combining polyols with specific molecular weights and hydroxyl values to achieve both cost-effectiveness and stain-free performance. This composite approach eliminates the need for separate plasticizer additives that cause staining in acryl-based systems.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If polyester-based pressure-sensitive adhesive from plant-derived materials is used, then environmental friendliness is improved, but cost increases

Engineering Contradiction:
Improveenvironmental impactVSAvoidcost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent optimizes parameters including polyester molecular weight (5000-150000), hydroxyl value (5-50 mg KOH/g), and carboxyl value (10-50 mg KOH/g) to achieve environmentally friendly plant-derived materials at competitive costs. These parameter controls ensure the adhesive performs well while maintaining economic viability.

Inventive Principle:
Principle #35Parameter changes

4Object-generated harmful factors

If polyester-based pressure-sensitive adhesive is used, then anti-staining property is improved, but wettability may be compromised

Engineering Contradiction:
Improveanti-staining propertyVSAvoidwettability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent carefully balances parameters including hydroxyl value (5-50 mg KOH/g) and molecular weight (5000-150000) to ensure the polyester-based adhesive maintains both anti-staining properties and adequate wettability. This parameter optimization prevents staining while ensuring proper spreading on adherends.

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 provides a cost-effective, environmentally friendly pressure-sensitive adhesive sheet that maintains excellent wettability and peelability while preventing adhesive residues and staining, suitable for surface protection applications.

Implementation Method 1

a crosslinking agent, wherein the carboxylic acid component contains a dicarboxylic acid having a side chain in an amount of 50 to 90% by weight and a tricarboxylic acid having a side chain in an amount of 10 to 50% by weight

Methodology Applied
Scientific EffectCrosslinking reaction: Chemical Bonding

Implementation Method 2

having adhesive strength proper for light peeling at the time of peeling off

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS9902886B2Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet
Publication Date: 2018.02.27 NITTO DENKO CORP

AI summary

A polyester-based pressure-sensitive adhesive composition which can be produced even from plant-derived raw materials with no need of using a costly silicone-based pressure-sensitive adhesive or the like and which is usable for producing a pressure-sensitive adhesive sheet excellent in wettability to an adherend, light peelability (removability), anti-staining property (little adhesive residues), and workability, and to provide a pressure-sensitive adhesive sheet using the composition. A polyester-based pressure-sensitive adhesive composition comprising a polyester obtained by condensation polymerization of at least a carboxylic acid component and a diol component, and a crosslinking agent, wherein the carboxylic acid component contains a dicarboxylic acid having a side chain in an amount of 50 to 90% by weight and a tricarboxylic acid having a side chain in an amount of 10 to 50% by weight, and wherein the polyester has a weight average molecular weight of 5000 to 150000.