Acryl Adhesive Composition for Polarizing Plate Corrosion Prevention

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Solution Overview

Problem

Conventional acryl-based adhesive compositions used in polarizing plates for liquid crystal display devices can cause corrosion of touch panel electrodes due to the reaction of carboxylic acid components, leading to deterioration of physical properties over time.

Innovation Solution

An acryl-based adhesive composition formed by polymerizing a monomer mixture containing (meth)acryl-based monomers with an acetoacetyl group, hydroxy group, and an alicyclic group, along with a curing agent comprising a metal chelate compound and an isocyanate, which creates a strong cross-linking structure without relying on carboxylic acid components, thereby preventing electrode corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a monomer having a carboxy group is used to form a strong cross-linking structure in the adhesive composition, then durability is improved, but the carboxylic acid component reacts with the transparent electrode of the touch panel causing corrosion and deteriorating the physical properties of the touch panel

Engineering Contradiction:
ImprovedurabilityVSAvoidcorrosion of transparent electrode
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes the harmful carboxylic acid component (monomer with carboxy group) from the adhesive composition while maintaining the beneficial cross-linking structure through alternative means (using monomers with hydroxy groups and acetoacetyl groups instead), thereby eliminating electrode corrosion while preserving durability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a composite monomer system combining (meth)acryl-based monomers with hydroxy groups and acetoacetyl groups to achieve both durability and non-corrosiveness, replacing the single-component carboxylic acid-based system with a multi-component composite that provides multiple functional benefits

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If the adhesive composition is formulated to achieve high durability without carboxylic acid components, then electrode corrosion is prevented, but achieving strong cross-linking structure becomes more difficult

Engineering Contradiction:
Improveelectrode corrosion preventionVSAvoidcross-linking structure strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The invention changes the chemical parameters of the adhesive composition by replacing carboxylic acid groups with hydroxy groups and acetoacetyl groups, and adjusts the curing mechanism to achieve strong cross-linking without corrosive components, thereby maintaining strength while preventing corrosion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces metal chelate compounds as intermediaries that facilitate cross-linking between monomers containing hydroxy groups and acetoacetyl groups, enabling strong bond formation without requiring carboxylic acid components that would cause corrosion

Inventive Principle:
Principle #24Intermediary (Mediator)

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 high durability and excellent adhesive strength to the polarizing plate, preventing corrosion of touch panel electrodes and maintaining the physical properties of the touch panel, even when a carboxylic acid component is present in trace amounts, while achieving a high glass transition temperature.

Implementation Method 1

formed by polymerizing a monomer mixture that contains a (meth)acryl-based monomer having an acetoacetyl group, a (meth)acryl-based monomer having a hydroxy group

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 2

a curing agent containing a metal chelate compound and an isocyanate compound, in which the acryl-based adhesive composition has a glass transition temperature of −30° C. or greater after curing

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS11492523B2Acryl-based adhesive composition, polarizing plate, and display device
Publication Date: 2022.11.08 LG CHEM LTD

AI summary

The present invention relates to an acryl-based adhesive composition containing an acryl-based copolymer, which is formed by polymerization of a monomer mixture that contains a (meth)acryl-based monomer having an acetoacetyl group, a (meth)acryl-based monomer having a hydroxy group, a (meth)acrylate monomer having an alicyclic group, and an alkyl (meth) acrylate-based monomer; and a curing agent containing a metal chelate compound and an isocyanate compound, in which the acryl-based adhesive composition has a glass transition temperature of −30° C. or greater after curing; and a polarizing plate and a display device prepared using the same.