Acryl-Based Adhesive Composition for LCD Durability and Rework
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Solution Overview
Problem
Adhesive compositions used in liquid crystal displays face challenges in maintaining adhesive durability under high temperature and humidity conditions while ensuring reworkability, as they often experience excessive adhesive strength increases or residue issues during peeling.
Innovation Solution
An adhesive composition with a specific ratio of initial adhesive strength to increased temperature adhesive strength of 2.0 or lower, formulated with an acryl-based copolymer and silane-based compounds, along with a tolylene diisocyanate-based cross-linking agent and anti-static agents, to balance durability and reworkability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a silane-based compound having an epoxy group is used as adhesive, then adhesive strength increases, but adhesive durability deteriorates under high temperature and humidity conditions
Solution Approach 1:
The patent changes the chemical parameters of the adhesive composition by combining silane-based compounds with epoxy groups, cyano acetyl groups, and acetoacetyl groups in specific proportions. This parameter optimization allows the adhesive to achieve both high initial strength and maintained durability under high temperature and humidity conditions, resolving the contradiction between strength and reliability
Solution Approach 2:
The patent creates a composite adhesive system by combining multiple silane-based compounds with different functional groups (epoxy, cyano acetyl, acetoacetyl) with acryl-based polymers. This composite approach leverages the complementary properties of each component: epoxy for initial strength, and cyano acetyl/acetoacetyl for heat resistance and reworkability, achieving both high strength and durability simultaneously
2Reliability
If adhesive strength is increased for better durability, then reworkability deteriorates due to excessive strength increase under high temperature and humidity
Solution Approach 1:
The patent optimizes the ratio parameters of different silane-based compounds in the adhesive composition. By controlling the proportions of epoxy group compounds (0.01-5 parts), cyano acetyl group compounds (0.1-5 parts), and acetoacetyl group compounds (0.1-5 parts) relative to the acryl-based polymer, the adhesive achieves balanced performance with controlled strength increase under heat and humidity, maintaining reworkability while improving durability
Solution Approach 2:
The patent introduces cross-linking agents as intermediary substances that mediate between the silane-based compounds and the acryl-based polymer. These cross-linking agents facilitate controlled cross-linking reactions that enhance durability without causing excessive strength increase, thereby preserving reworkability. The cross-linking agent acts as a buffer that moderates the adhesive strength response to temperature and humidity changes
3Strength
If adhesive strength is increased to prevent peeling, then adhesive residue on substrate increases during peeling
Solution Approach 1:
The patent adjusts the chemical composition parameters by incorporating silane-based compounds with specific functional groups that provide controlled adhesion. The cyano acetyl and acetoacetyl groups contribute to adhesive strength while maintaining clean peeling characteristics, preventing excessive residue on substrates even when high strength is achieved
Solution Approach 2:
The patent employs acryl-based polymers as the primary adhesive matrix that provides initial bonding strength but is designed to peel cleanly without excessive residue. The silane-based compounds enhance durability without compromising the clean-peel特性 of the acryl-based system, allowing the adhesive to function effectively during use and then separate cleanly when needed
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 excellent adhesive durability and reworkability by controlling adhesive strength ratios, preventing excessive increases under high temperature and humidity, and ensuring the adhesive does not remain on substrates during peeling.
Implementation Method 1
The cross-linkage of the acryl-based adhesive employs the linkage of a cross-linking agent with a functional monomer of the acryl-based polymer
Implementation Method 2
an adhesive composition containing a silane-based compound having an epoxy group has been known as an adhesive
Implementation Method 3
an adhesive composition containing a silane-based compound having a cyano acetyl group
Data Source
AI summary
Provided is an adhesive composition whose initial adhesive strength (A) and adhesive strength at increased temperature (B) satisfy a ratio (B/A) of 2.0 or lower, wherein the (A) value is measured through a peeling test after a sample is left for 24 hours at 23° C. and 50% relative humidity, and the (B) value is measured through a peeling test after a sample is left for 48 hours at 50° C. and 50% RH; the sample is prepared by laminating an adhesive-attached polarizing plate having a size of 25 mm×100 mm on a substrate at a pressure of 0.25 MPa and treating the laminate in an autoclave, the adhesive being formed from the adhesive composition; andthe peeling test is performed by peeling the adhesive from the glass substrate at a peeling rate of 300 mm/min and a peeling angle of 180° using a universal testing machine.