Radically Curable Adhesive for Polarizing Plates
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Solution Overview
Problem
Current polarizing plate adhesives face challenges in maintaining adhesiveness and curing rate in high-humidity environments, leading to potential curling and deterioration of initial optical properties, and require additional pretreatment processes.
Innovation Solution
A radically curable adhesive composition comprising a compound represented by Formula 1, a vinyl ether-based compound, a carboxylic acid compound with unsaturated double bonds, and a radical initiator, which forms a composite through copolymerization to maintain adhesiveness and humidity resistance, and includes a photoacid generator for improved acidity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If aqueous adhesives are used for protective films other than TAC films, then the adhesive composition can be simple, but the adhesiveness becomes poor and curling appears after drying
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by using PVA-based resin with specific molecular weights (70,000-1,000,000) and incorporating crosslinking agents (glyoxal, glutaraldehyde, or dialdehyde starch) at controlled amounts (0.1-10 parts by weight per 100 parts resin). This transforms the adhesive from a simple aqueous solution to a chemically modified composition that maintains simplicity while achieving reliable adhesiveness across different protective film materials.
2Device complexity
If aqueous adhesives are used, then the adhesive composition can be simple, but the initial optical properties deteriorate due to curling after drying
Solution Approach 1:
The patent modifies the adhesive composition by incorporating crosslinking agents that create a three-dimensional network structure within the PVA-based resin. This chemical transformation prevents water evaporation-induced curling during the drying process, thereby maintaining the flatness and initial optical properties of the polarizing plate while keeping the composition relatively simple.
Solution Approach 2:
The patent creates a composite adhesive system by combining PVA-based resin with crosslinking agents (glyoxal, glutaraldehyde, or dialdehyde starch). This composite structure provides both the simplicity of an aqueous adhesive and the dimensional stability needed to prevent curling, thus preserving the initial optical properties of the polarizing plate.
3Device complexity
If aqueous adhesives are used, then the adhesive composition can be simple, but the defect rate increases due to differences in water permeability and thermal expansion during drying
Solution Approach 1:
The patent adjusts the adhesive composition by adding crosslinking agents that modify the physical and chemical properties of the PVA-based resin. This creates a more uniform adhesive layer with controlled water permeability and thermal expansion characteristics, reducing defects during the drying process while maintaining composition simplicity.
4Speed
If radically curable adhesives with acrylamide-based compounds are used, then the curing rate improves, but adhesiveness lowers in high-humidity environments
Solution Approach 1:
The patent changes the chemical composition by using PVA-based resin with specific molecular weight ranges (70,000-1,000,000) and incorporating crosslinking agents at optimized concentrations. This creates an adhesive system that maintains rapid curing characteristics while achieving high adhesiveness in humid environments through enhanced crosslinking density and hydrophobicity.
5Speed
If radically curable adhesives with acrylamide-based compounds are used, then the curing rate improves, but additional pretreatment processes are required
Solution Approach 1:
The patent modifies the adhesive composition to include PVA-based resin with specific molecular weights and crosslinking agents that enable direct application without pretreatment. The crosslinking agents (glyoxal, glutaraldehyde, or dialdehyde starch) provide sufficient reactivity to achieve rapid curing on the polarizer surface without requiring additional drying or plasma treatment steps, thus maintaining high curing speed while simplifying the manufacturing process.
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 maintains high adhesiveness and curing rate in high-humidity environments, enhancing the durability of polarizing plates and reducing the need for additional pretreatment processes, thereby improving manufacturing productivity and optical properties.
Implementation Method 1
a radical initiator, which forms a composite through copolymerization
Implementation Method 2
a compound including a hydroxy group, a vinyl ether-based compound, and a carboxylic acid compound
Data Source
AI summary
There are provided a radically curable adhesive composition maintaining adhesiveness thereof even in high-humidity environments, and a polarizing plate including the radically curable adhesive composition. The radically curable adhesive composition includes: a compound represented by Formula 1; a vinyl ether-based compound; a carboxylic acid compound having at least one unsaturated double bond; and a radical initiator.