Optical Laminate Barrier Layer Adhesiveness
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Solution Overview
Problem
In liquid crystal display devices with horizontal electric field systems, the adhesiveness between the film substrate and the pressure sensitive adhesive layer is often compromised, leading to durability issues and suboptimal display performance due to the transfer of components from the adhesive layer.
Innovation Solution
An optical laminate configuration is developed, featuring a film substrate, a barrier layer with specific polymerizable groups, and a pressure sensitive adhesive layer, where the barrier layer is formed with a monomer having a polymerizable group, satisfying conditions such as the presence of a functional group that reacts with hydroxyl groups and minimal hydroxyl groups within half the barrier layer's thickness, ensuring excellent adhesiveness and preventing liquid crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer is provided between the film substrate and the pressure sensitive adhesive layer to improve durability and suppress component transfer, then the adhesiveness to the pressure sensitive adhesive layer deteriorates
Solution Approach 1:
The barrier layer is designed with non-uniform hydroxyl group distribution: concentrated at the film substrate interface and absent from the pressure sensitive adhesive layer interface. This local differentiation allows the barrier layer to provide durability while maintaining adhesiveness at the critical bonding surface.
Solution Approach 2:
The barrier layer uses a composite structure combining a cycloolefin-based polymer matrix with specifically positioned hydroxyl groups. This composite approach enables simultaneous achievement of barrier functionality (durability) and adhesive compatibility through strategic functional group placement.
2Reliability
If a barrier layer is provided to suppress transfer of components from the pressure sensitive adhesive layer, then the adhesiveness to the pressure sensitive adhesive layer deteriorates
Solution Approach 1:
The barrier layer exhibits spatially differentiated properties: it possesses component transfer suppression capability through its barrier material composition while maintaining adhesiveness through localized hydroxyl groups at the pressure sensitive adhesive layer interface.
3Strength
If the barrier layer contains hydroxyl groups to improve adhesiveness, then liquid crystallinity may occur in the barrier layer
Solution Approach 1:
Hydroxyl groups are localized specifically at the pressure sensitive adhesive layer interface rather than being uniformly distributed throughout the barrier layer. This localized placement provides adhesiveness while preventing the uniform molecular arrangement required for liquid crystallinity.
Solution Approach 2:
The concentration and spatial distribution of hydroxyl groups are precisely controlled within specific ranges and positions. By adjusting these parameters, the invention achieves optimal adhesiveness while maintaining isotropic composition that prevents liquid crystallinity.
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
This configuration enhances the adhesiveness between the barrier and pressure sensitive adhesive layers, improving the durability and display performance of liquid crystal display devices by maintaining the integrity of the adhesive layer and preventing liquid crystallinity in the barrier layer.
Implementation Method 1
a functional group that reacts with a hydroxyl group to form a covalent bond is present on a surface of the barrier layer on a pressure sensitive adhesive layer side
Implementation Method 2
the barrier layer is formed of a composition for forming a barrier layer, containing a monomer having a polymerizable group
Data Source
AI summary
An optical laminate having a barrier layer having excellent adhesiveness to a pressure sensitive adhesive layer, a polarizing plate, and an image display device. The optical laminate has a film substrate, a barrier layer, and a pressure sensitive adhesive layer in this order, in which the barrier layer is formed of a composition for forming a barrier layer, containing a monomer having a polymerizable group, and satisfies Condition 1: a functional group that reacts with a hydroxyl group to form a covalent bond is present on a surface of the barrier layer on a pressure sensitive adhesive layer side and Condition 2: no hydroxyl group other than the hydroxyl group included in the functional group is present in a region from the surface of the barrier layer on the pressure sensitive adhesive layer side to a half of a thickness of the barrier layer.