Cloud Point-Resistant Optical Clear Adhesives for Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optically clear adhesives (OCAs) used in optical displays, such as LCDs, tend to become hazy or 'white' due to cloud point issues when exposed to high temperature and humidity conditions, leading to optical clarity loss.
Innovation Solution
Incorporating hydrophilic moieties into the OCA matrix, specifically using precursors that include 75-95 parts by weight of alkyl acrylate, 0-5 parts of copolymerizable polar monomer, and 1-25 parts of hydrophilic polymeric compounds, or 60-95 parts of alkyl acrylate, 0-5 parts of copolymerizable polar monomer, and 5-50 parts of hydroxyl-containing monomers, to create cloud point-resistant adhesive compositions with high moisture-vapor transmission rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional OCAs are used in optical displays, then they provide basic adhesive functionality, but they become hazy or white due to cloud point issues when exposed to high temperature and humidity conditions
Solution Approach 1:
The patent modifies the chemical composition parameters of the OCA by incorporating hydrophilic polymeric compounds (1-25 parts by weight based on 100 parts alkyl acrylate) and hydroxyl-containing monomers (5-50 parts by weight with OH equivalent weight <400). These compositional changes enable the adhesive to maintain optical clarity by preventing water saturation and phase separation under high temperature and humidity conditions, thereby eliminating cloud point haze while preserving adhesive functionality
Solution Approach 2:
The patent creates a composite adhesive system by combining alkyl acrylate (75-95 parts by weight) with copolymerizable polar monomers (0-5 parts) and hydrophilic polymeric compounds or hydroxyl-containing monomers. This composite formulation integrates materials with complementary properties: the alkyl acrylate provides adhesive base properties, the polar monomers enhance polarity and water interaction, and the hydrophilic components prevent water saturation. The synergistic combination resolves the cloud point issue while maintaining bonding performance
2Reliability
If hydrophilic moieties are incorporated into the OCA matrix to prevent cloud point haze, then optical clarity is maintained under high temperature and humidity, but the adhesive composition becomes more complex
Solution Approach 1:
The patent establishes specific quantitative ranges for each component to balance performance and simplicity: 75-95 parts by weight of alkyl acrylate, 0-5 parts of copolymerizable polar monomer, and 1-25 parts of hydrophilic polymeric compound or 5-50 parts of hydroxyl-containing monomer. These parameter specifications provide a systematic framework that achieves cloud point resistance through controlled composition rather than arbitrary complexity, making the formulation both effective and manufacturable
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 resulting adhesive compositions remain clear and haze-free even after high temperature/humidity accelerated aging tests, maintaining optical clarity and bond strength, suitable for applications like laminating polarizers to LCDs and attaching optical films to mobile devices.
Implementation Method 1
the adhesive has a moisture-vapor transmission rate of at least 400 g/m2/day
Implementation Method 2
Incorporating hydrophilic moieties into the OCA matrix, specifically using precursors that include 75-95 parts by weight of alkyl acrylate, 0-5 parts of copolymerizable polar monomer, and 1-25 parts of hydrophilic polymeric compounds
Data Source
AI summary
Optically clear adhesives and laminates that include the adhesives are provided. The adhesives and laminates remain haze-free and are cloud point-resistant when placed in environments of high humidity and elevated temperature. The adhesives and laminates are useful in optical electronic display applications.