Moth-Eye Antireflection Film Protection Adhesive
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Solution Overview
Problem
Conventional protection films fail to maintain the antireflection properties of moth-eye films due to adhesive deposit issues when peeled off, leading to contamination and performance degradation, especially after autoclave or heat treatments.
Innovation Solution
A laminated body with a protection film featuring an adhesive layer formed by cross-linking a (meth)acrylic acid ester copolymer, where the copolymer has a weight-average molecular weight between 600,000 and 1,500,000, and specific monomer compositions to prevent adhesive deposit and ensure sufficient adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional protection film is applied to the moth-eye film, then the moth-eye film surface is protected from external factors, but adhesive deposit occurs on the moth-eye film when the protection film is peeled off, degrading the antireflection property
Solution Approach 1:
The patent applies parameter changes by carefully controlling the molecular weight of the adhesive polymer (10,000 to 1,000,000) and the heating temperature (50°C to 200°C) during lamination. These parameter adjustments optimize the adhesive's flow and bonding characteristics, allowing strong adhesion during application while enabling clean removal without deposit, thus resolving the contradiction between protection and adhesive residue.
Solution Approach 2:
The patent utilizes the dynamic properties of the adhesive layer by heating it to a temperature where it becomes sufficiently fluid to flow into and bond with the moth-eye structure's fine protrusions. This dynamic behavior allows the adhesive to dynamically adapt to the surface topology during bonding, then be dynamically removed by peeling when cooled, providing both strong bonding and clean removal without permanent deposit.
2Reliability
If the protection film is strongly bonded to the moth-eye film to prevent dirt deposition, then protection effectiveness increases, but the film becomes difficult to peel off without leaving adhesive residue
Solution Approach 1:
The patent employs parameter changes by optimizing the adhesive layer thickness (1 µm to 100 µm) and controlling the molecular weight and heating temperature. These parameter adjustments create an adhesive layer that achieves strong bonding for effective protection while maintaining the ability to be cleanly removed by peeling, thus resolving the contradiction between protection effectiveness and peeling ease.
3Strength
If the adhesive layer penetrates deeply into the moth-eye structure to achieve strong adhesion, then bonding strength increases, but adhesive deposit remains in the fine protrusions after peeling
Solution Approach 1:
The patent applies parameter changes by precisely controlling the adhesive layer thickness (1 µm to 100 µm) and the molecular weight (10,000 to 1,000,000). These parameter optimizations allow the adhesive to penetrate sufficiently into the moth-eye structure for strong bonding while limiting excessive penetration that would cause deposit, thus resolving the contradiction between adhesion strength and adhesive deposit prevention.
Solution Approach 2:
The patent applies partial action by controlling the adhesive layer to penetrate to an optimal depth into the moth-eye protrusions - sufficient to achieve strong bonding but not excessive to cause problematic deposit. This controlled partial penetration resolves the contradiction between needing strong adhesion and avoiding adhesive residue in the fine structure.
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 solution prevents adhesive deposit on the moth-eye film surface, maintaining the antireflection properties and ensuring easy peeling without contamination, even after heat treatments.
Implementation Method 1
an adhesive layer formed by cross-linking a (meth)acrylic acid ester copolymer
Implementation Method 2
The moth-eye structure allows the refractive index variation in the boundary between the external environment (air) and the surface of an article to be quasi-continuous
Data Source
Figure 1~3
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Figure 7~9
AI summary
The present invention provides a laminated body including an antireflection film onto the surface of which bonded is a protection film excellent in the temporary adhesiveness and hardly undergoing the occurrence of adhesive deposit after being peeling off. The laminated body of the present invention is a laminated body including: an antireflection film; and a protection film bonded onto the antireflection film, wherein the surface of the antireflection film includes a plurality of protrusions wherein the width between the tops of adjacent protrusions is equal to or less than the visible light wavelength; the protection film includes a supporting film and an adhesive layer in contact with the antireflection film; the adhesive layer is a layer constituted with a material formed by cross-linking, with a cross-linking agent (B), a (meth)acrylic acid ester copolymer (A); the weight-average molecular weight of the (meth)acrylic acid ester copolymer (A) is 600,000 or more and less than 1,500,000; the (meth)acrylic acid ester copolymer (A) is a copolymer formed by polymerizing monomer components including, in relation to the total amount of the monomer components set at 100% by mass, 70 to 98% by mass of a (meth)acrylic acid alkyl ester monomer (a) including a noncyclic alkyl group containing 4 to 9 carbon atoms, 1.5 to 25% by mass of a (meth)acrylic acid ester monomer (b) containing an aliphatic ring, and 0.5 to 5% by mass of a (meth)acrylic-based monomer (c) containing a functional group exhibiting reactivity with the cross-linking agent (B); and the area proportion of the components each having a molecular weight of 100,000 or less, obtained by gel permeation chromatography measurement, in relation to the area of the whole of the (meth)acrylic acid ester copolymer (A) set at 100%, is less than 3.0%.