Siloxane Resin Composition for Touch Panel Hard Coating
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Solution Overview
Problem
Current hard coating materials for touch panels lack sufficient hardness, abrasion resistance, and pattern processability, particularly for capacitance type touch panels which require high hardness and are costly to produce due to high-temperature processing, and existing UV-curable compositions are not suitable for manufacturing processes.
Innovation Solution
A siloxane resin composition comprising polysiloxane with carboxyl and radical polymerizable groups, a photo-radical polymerization initiator, and a compound without Si-O-Si bonds, which allows for high hardness, excellent abrasion resistance, and pattern processability through UV and thermal curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UV-curable hard coating materials are used for touch panels, then productivity is improved due to short curing time, but hardness and abrasion resistance are insufficient
Solution Approach 1:
The patent uses a composite coating system comprising a base coat layer and a UV-curable hard coat layer. The base coat contains silane-modified polymer and silane crosslinking agent that form a hard, abrasion-resistant foundation through silane crosslinking. The UV-curable hard coat layer provides additional hardness and protection. This composite structure allows the final coating to achieve both high hardness/abrasion resistance and fast curing, resolving the contradiction between these properties.
2Strength
If inorganic hard coatings (SiO2 or SiNx) are used for capacitance type touch panels, then hardness is improved, but production cost increases due to high-temperature processing
Solution Approach 1:
The patent changes the curing parameter from high-temperature thermal processing (required for inorganic coatings like SiO2 or SiNx) to UV irradiation at lower temperatures. The UV-curable hard coat layer cures at temperatures suitable for capacitance type touch panels with ITO films, avoiding the need for high-temperature equipment and reducing production costs while maintaining high hardness.
Solution Approach 2:
The patent replaces the thermal curing mechanism (heat-based) with photo-polymerization (UV light-based). Instead of using thermal energy to cure inorganic coatings at high temperatures, the invention uses UV irradiation to initiate polymerization of the hard coat material, achieving similar or better hardness at lower temperatures and reduced cost.
3Strength
If inorganic hard coatings are formed by CVD or high-temperature treatment, then hardness is improved, but energy consumption increases
Solution Approach 1:
The patent changes the energy input parameter from thermal energy (high-temperature treatment or CVD) to electromagnetic energy (UV irradiation). UV curing occurs at lower temperatures and consumes less energy compared to high-temperature thermal processes, while still achieving high hardness in the protective coating.
Solution Approach 2:
The patent substitutes thermal energy-based curing mechanisms with photo-polymerization using UV light. This replacement dramatically reduces energy consumption since UV curing occurs at ambient or slightly elevated temperatures compared to the high temperatures required for CVD or thermal treatment of inorganic coatings.
4Manufacturing precision
If existing UV-curable compositions are used, then pattern processability is required, but manufacturing process compatibility is poor
Solution Approach 1:
The patent applies different materials with different properties to different layers: the base coat layer uses silane-modified polymer for adhesion and flexibility, while the UV-curable hard coat layer uses photo-polymerizable monomers and oligomers for hardness and pattern processability. This layered approach with localized material optimization allows the coating to achieve both manufacturing process compatibility and excellent pattern processability.
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 siloxane resin composition achieves high hardness, improved abrasion resistance, and efficient pattern processability, reducing production costs and energy consumption while maintaining high performance.
Implementation Method 1
a photo-radical polymerization initiator, and a compound without Si-O-Si bonds, which allows for high hardness, excellent abrasion resistance, and pattern processability through UV and thermal curing
Implementation Method 2
polysiloxane with carboxyl and radical polymerizable groups
Data Source
AI summary
To provide a siloxane resin composition which is superior in pattern processability and yields a cured film with high hardness and excellent abrasion resistance by means of UV curing and thermal curing. A siloxane resin composition including (A) polysiloxane having a carboxyl group and a radical polymerizable group, (B) a photo-radical polymerization initiator and (C) a compound having a radical polymerizable group and not having a Si-O-Si bond.