Acrylate Adhesive Composition for LCD Optical Member
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Solution Overview
Problem
Optical films in LCD display devices face issues with light leakage and durability due to excessive initial peeling force and light leakage, which are not adequately addressed by existing adhesive compositions.
Innovation Solution
An adhesive composition comprising a (meth)acrylate copolymer with specific weight ratios of C1-20 alkyl(meth)acrylate, aromatic group-containing, hydroxy group-containing, and carboxyl group-containing monomers, combined with a crosslinking agent and silane coupling agent, and a crosslinking catalyst, which forms a high-gel-fraction adhesive with improved storage elasticity and adhesion stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing adhesive compositions are used, then the adhesive provides basic bonding, but excessive initial peeling force and light leakage occur
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by using a (meth)acrylate copolymer with specific weight ratios of C1-20 alkyl(meth)acrylate (50-90 wt%), aromatic group-containing monomer (0.01-30 wt%), hydroxy group-containing monomer (0.01-10 wt%), and carboxyl group-containing monomer (0.01-10 wt%). This compositional parameter change optimizes the balance between peel strength and light leakage prevention
Solution Approach 2:
The patent creates a composite adhesive system combining multiple functional components: the (meth)acrylate copolymer base polymer, crosslinking agents (isocyanate and epoxy), silane coupling agents, and crosslinking catalysts. This composite material approach allows simultaneous optimization of mechanical bonding properties and optical properties to reduce light leakage
2Strength
If adhesive composition is formulated for strong adhesion, then peel strength improves, but gel fraction increases excessively
Solution Approach 1:
The patent precisely controls the gel fraction parameter by adjusting the crosslinking agent concentration (0.01-10 wt%), silane coupling agent concentration (0.01-5 wt%), and crosslinking catalyst amount (0.01-5 wt%). This parameter optimization ensures the gel fraction reaches 85% or more while maintaining compositional stability and preventing excessive crosslinking that would compromise adhesion
3Strength
If crosslinking agent amount is increased, then storage elasticity improves, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the crosslinking agent amount parameter within 0.01-10 wt% to achieve desired storage elasticity (0.2-0.5 MPa) while maintaining ease of manufacture. The specific range allows sufficient crosslinking for elastic properties without excessive complexity in formulation and processing
Solution Approach 2:
The patent introduces a silane coupling agent as an intermediary substance that facilitates controlled crosslinking between the (meth)acrylate copolymer chains and crosslinking agents. This intermediary mechanism enables achieving high storage elasticity through moderate crosslinking agent amounts, simplifying the manufacturing process while maintaining performance
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 a gel fraction of 85% or more, providing superior peel strength, reduced light leakage, and improved durability, ensuring uniform brightness across the optical member with a brightness difference of 0.5 or less between edge and center portions.
Implementation Method 1
about 0.01 to about 10 parts by weight of a crosslinking agent... about 0.01 to about 5 parts by weight of a crosslinking catalyst... the adhesive composition provides an adhesive having a gel fraction of about 85% or more
Implementation Method 2
about 0.01 to about 5 parts by weight of a silane coupling agent
Implementation Method 3
The aromatic group-containing monomer may have positive birefringence
Data Source
AI summary
An adhesive composition and an optical member using the same, the adhesive composition including about 100 parts by weight of a (meth)acrylate copolymer including repeating units derived from a C1-20 alkyl(meth)acrylate monomer, an aromatic group-containing monomer, and a carboxyl group-containing monomer; about 0.01 to about 10 parts by weight of a crosslinking agent; about 0.01 to about 5 parts by weight of a silane coupling agent; and about 0.01 to about 5 parts by weight of a crosslinking catalyst.