Polarizing Plate Protective Layer Shrinkage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polarizing plates with pressure sensitive adhesives directly applied to polarizers face durability issues and light leakage due to differences in shrinkage rates and water resistance problems under high humidity conditions.
Innovation Solution
A polarizing plate with a protective layer formed from a radically curable composition containing a compound represented by [Chemical Formula 1], a vinyl ether compound, and a carboxylic acid compound, which provides superior water resistance and heat resistance through copolymerization, ensuring adhesion and durability even under high humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pressure sensitive adhesive is directly formed on the polarizer surface, then the polarizing plate structure is simplified and manufacturing is easier, but durability deteriorates and cracks are easily generated under severe conditions
Solution Approach 1:
The patent divides the adhesive system into two separate functional layers: a protective layer formed on the polarizer surface with controlled shrinkage properties, and a pressure sensitive adhesive layer formed on the protective layer. This segmentation allows each layer to perform its specific function optimally - the protective layer provides dimensional stability and prevents cracking, while the PSA layer provides bonding capability.
Solution Approach 2:
The protective layer acts as an intermediary layer between the polarizer and the pressure sensitive adhesive. It mediates the mechanical stress and shrinkage differences that would otherwise directly affect the polarizer, preventing crack propagation while maintaining adhesion through the PSA layer on its surface.
2Strength
If a protective film is attached using adhesive, then the polarizer is protected, but curling occurs due to difference in shrinkage rates between the protective film and adhesive
Solution Approach 1:
The patent changes the key parameter of shrinkage rate by selecting specific polymers for the protective layer with shrinkage rates matched to the polarizer (within ±5% of the polarizer's shrinkage rate). This parameter matching eliminates the shrinkage differential that causes curling, while the protective layer still provides necessary protection.
3Strength
If a hydroxyethyl acrylate resin is used as protective layer forming agent, then the protective layer provides basic protection, but water resistance and glass transition temperature properties are insufficient under high humidity conditions
Solution Approach 1:
The patent uses a composite polymer system in the protective layer comprising both hydroxyethyl acrylate resin and polymers with specific shrinkage rates (such as polyvinyl alcohol or cellulose derivatives). This composite approach combines the adhesion properties of hydroxyethyl acrylate with the dimensional stability and water resistance of the second polymer, achieving both protective function and humidity resistance.
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 polarizing plate maintains excellent durability and optical properties with high heat resistance and water resistance, reducing the risk of damage and light leakage, and improves manufacturing productivity.
Implementation Method 1
a protective layer formed on at least one surface of the polarizer, wherein the protective layer is formed of a cured product of a radically curable composition
Data Source
AI summary
The present disclosure relates to a polarizing plate excellent durability even under high humidity conditions and more particularly, to a polarizing plate including a polarizer and a protective layer formed on at least one surface of the polarizer, wherein the protective layer is formed of a cured product of a radically curable composition including a compound represented by the following [Chemical Formula 1]; a vinyl ether compound; a carboxylic acid compound including at least one unsaturated double bond; and a radical initiator.