Optical Adhesive Composition for Display Panels
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Solution Overview
Problem
Existing optical adhesives face challenges in achieving optimal adhesion, minimal curing contraction, and sufficient elongation while avoiding bubble formation between ITO films and glass window layers, which affects the reliability and visibility of display panels.
Innovation Solution
An optical adhesive composition incorporating a urethane (meth)acrylate resin with hydroxyl and vinyl groups, specifically formulated with a curing contraction ratio of 0-3% and adhesion of 30-80 kgf, including a photocurable monomer, photoinitiator, UV absorber, and antioxidant, to ensure stable bonding and minimal stress on substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional optical adhesives are used, then adhesion is achieved, but curing contraction is excessive causing stress on substrates
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive by incorporating specific ratios of urethane polymer (1-10 parts), polyol (5-20 parts), and (meth)acrylic monomer (1-10 parts) to control the curing contraction ratio within 0-5% and maintain adhesion strength of 30-80 kgf
Solution Approach 2:
The patent creates a composite adhesive system combining urethane polymer, polyol, and (meth)acrylic monomer in specific proportions to achieve both low curing contraction and high adhesion, preventing substrate stress while maintaining bonding strength
2Strength
If adhesive formulation is optimized for adhesion, then bonding strength improves, but elongation becomes insufficient
Solution Approach 1:
The patent adjusts the molecular weight and compositional parameters of the adhesive components, specifically using polyol with molecular weight 500-5000 and controlling the equivalence ratio between polyol and isocyanate (1.05-1.2:1) to simultaneously achieve high adhesion and sufficient elongation (200-800%)
3Stress or pressure
If curing contraction is minimized, then substrate stress is reduced, but adhesion may be compromised
Solution Approach 1:
The patent develops a composite adhesive formulation where urethane polymer (1-10 parts) provides adhesion, polyol (5-20 parts) provides flexibility and elongation, and (meth)acrylic monomer (1-10 parts) controls curing contraction, achieving a balance of 0-5% contraction with 30-80 kgf adhesion
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 provides improved adhesion, reduced curing contraction, and enhanced elongation, preventing bubble formation and stress on substrates, thereby enhancing the reliability and outdoor visibility of display panels.
Implementation Method 1
a copolymer of a urethane polymer having at least one hydroxyl group and a (meth)acrylic monomer having an isocyanate and a vinyl group
Implementation Method 2
The optical adhesive composition may further include a photocurable monomer, a photoinitiator, a UV absorber, and an antioxidant
Data Source
AI summary
An optical adhesive composition includes a urethane (meth)acrylate resin having at least one hydroxyl group and at least one vinyl group, the urethane (meth)acrylate resin having a curing contraction ratio expressed by Equation 1 of about 0 to about 3%; and an adhesion of about 30 to about 80 kgf:Curing contraction ratio (%)=(A−B)/A×100, [Equation 1]where A is a specific gravity of the optical adhesive composition before curing, and B is a specific gravity of the solid optical adhesive composition after curing.