Touch Panel Adhesive Composition Sebum Resistance

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Solution Overview

Problem

Adhesives for touch panels face challenges in providing excellent chemical resistance, durability under high-temperature and high-humidity conditions, and superior adhesion and wettability, while also resisting sebum and preventing damage to sensors.

Innovation Solution

An adhesive composition comprising a partially polymerized acrylic resin, a multifunctional crosslinking agent, and urethane acrylate, with specific formulations and properties to achieve high gel content and controlled sebum permeation, ensuring excellent adhesion and chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pressure-sensitive adhesives are used, then basic adhesion is achieved, but chemical resistance to sebum and durability under high-temperature/high-humidity conditions deteriorate

Engineering Contradiction:
Improvechemical resistanceVSAvoidsebum permeation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesive composition uses a composite system combining acrylic polymer (with specific molecular weight 400,000-1,600,000), multifunctional crosslinking agent, and urethane acrylate. This composite formulation creates a chemically resistant network structure that blocks sebum permeation while maintaining adhesion to touch panel substrates under high-temperature and high-humidity conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges: acrylic polymer molecular weight (400,000-1,600,000), crosslinking agent amount (0.01-10 parts by weight per 100 parts polymer), and urethane acrylate content. These parameter optimizations transform the adhesive's chemical resistance and sebum barrier properties while ensuring durability in severe environmental conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If adhesive formulation is optimized for chemical resistance, then sebum resistance improves, but adhesion and wettability to various substrates may deteriorate

Engineering Contradiction:
Improvesebum resistanceVSAvoidadhesion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The adhesive composition achieves different functional properties in different regions of its molecular structure: the acrylic polymer backbone provides adhesion and wettability to substrates, while the crosslinked network formed by multifunctional crosslinking agent and urethane acrylate creates a chemically resistant, sebum-impermeable barrier. This local differentiation of material properties resolves the contradiction between adhesion and chemical resistance.

Inventive Principle:
Principle #3Local quality

3Reliability

If crosslinking agent amount is increased to improve chemical resistance, then gel content increases, but adhesion and flexibility may deteriorate

Engineering Contradiction:
Improvechemical resistanceVSAvoidadhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent precisely controls the crosslinking agent amount at 0.01-10 parts by weight per 100 parts acrylic polymer, with urethane acrylate also within specific ranges. This parameter optimization ensures sufficient crosslinking for chemical resistance and sebum resistance while maintaining adhesion strength and substrate flexibility, preventing the deterioration that would result from excessive crosslinking.

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 adhesive composition achieves superior chemical resistance, durability, and adhesion to various substrates, preventing sebum permeation and extending the life of touch panels.

Implementation Method 1

an adhesive composition for a touch panel includes: a partially polymerized acrylic resin; a multifunctional crosslinking agent in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the partially polymerized acrylic resin; and an urethane acrylate

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

X 2 is the distance of artificial sebum permeating a lateral side of a sample measured after soaking the sample in artificial sebum

Methodology Applied
Scientific EffectPermeation resistance: Permeation

Data Source

PatentEP2644676B1Adhesive composition for touch panel, adhesive film, and touch panel
Publication Date: 2015.08.12 LG HAUSYS LTD
  • EP2644676B1 patent drawingFigure 1~3
  • EP2644676B1 patent drawingFigure 4
  • EP2644676B1 patent drawing

AI summary

The present invention relates to an adhesive composition for a touch panel, and adhesive film, and to a touch panel. When the adhesive composition of the present invention is applied to the touch panel, for example, to an electrostatic capacitance-type touch panel, the present invention has superior durability under high-temperature and high-humidity conditions and superior wettability and adhesiveness to various objects to be adhered, and can provide the adhesive composition and the adhesive film having excellent durability to chemicals, such as resistance to sebum.