Self-Healing Polythiolene Coating for Optical Substrates
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Solution Overview
Problem
Current self-healing coatings for organic glasses do not adequately improve the final scratch resistance after healing, necessitating a combination of specific self-healing and abrasion-resistant coatings for enhanced performance.
Innovation Solution
A two-layer coating system comprising a transparent optical polymer substrate with an intermediate abrasion-resistant coating obtained from epoxysilane via sol-gel process and a transparent outer self-healing coating made from a polythiol-ene matrix, incorporating conductive colloids, which is cured to achieve a specific glass transition temperature and thickness range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a self-healing coating is applied to organic glass, then the coating can repair scratches through thermal or UV treatment, but the final scratch resistance after healing is not adequately improved
Solution Approach 1:
The patent applies a composite coating structure consisting of an inner abrasion-resistant coating layer and an outer self-healing coating layer. The inner layer provides durable scratch resistance through crosslinked polymer networks, while the outer layer enables scratch repair through shape memory effects or capsule-based healing mechanisms. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The coating system is segmented into functionally distinct layers: an inner abrasion-resistant layer and an outer self-healing layer. Each layer is optimized for its specific function, with the inner layer providing structural durability and the outer layer providing repair capability. This segmentation allows each layer to perform its specialized function without compromising the other.
2Reliability
If multiple coating layers are applied to provide both self-healing and abrasion resistance, then scratch resistance is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies the inner abrasion-resistant coating first and allows it to cure and form a stable substrate before applying the outer self-healing coating. This preliminary action ensures that each layer is properly established and bonded before the next layer is applied, simplifying the overall manufacturing process while maintaining high scratch resistance.
Solution Approach 2:
The patent combines the application of multiple coating layers into a integrated manufacturing process where the inner and outer coatings are applied in sequence and cured together or in a coordinated manner. This merging of steps reduces process complexity compared to applying and curing each layer separately.
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 combination significantly enhances scratch resistance and transparency, maintaining optical clarity while effectively repairing scratches upon heating, as demonstrated by reduced haze and improved resistance in testing.
Implementation Method 1
a transparent intermediate abrasion-resistant coating obtained from at least one epoxysilane by a sol-gel process
Implementation Method 2
a transparent intermediate abrasion-resistant coating obtained from at least one epoxysilane by a sol-gel process
Implementation Method 3
a transparent outer coating comprising a polythiol-ene matrix obtained by curing a liquid monomer mixture comprising at least one polyfunctional thiol and at least one polyfunctional allyl monomer
Implementation Method 4
said cured polythiol-ene matrix having a glass transition temperature comprised in the range from 40° C. to 70° C.
Implementation Method 5
a transparent outer coating comprising a polythiol-ene matrix obtained by curing a liquid monomer mixture comprising at least one polyfunctional thiol and at least one polyfunctional allyl monomer, said cured polythiol-ene matrix having a glass transition temperature comprised in the range from 40° C. to 70° C.
Data Source
AI summary
The present invention is drawn to an optical article comprising: (a) a transparent optical polymer substrate, (b) a transparent intermediate abrasion-resistant coating obtained from at least one epoxysilane by a sol-gel process, and (c) a transparent outer coating comprising a polythiolene matrix obtained by curing a liquid monomer mixture comprising at least one polyfunctional thiol and at least one polyfunctional allyl monomer, said cured polythiol-ene matrix having a glass transition temperature comprised in the range from 40° C. to 70° C. and a thickness from 3.5 μm to less than 10 μm. It is also drawn to a method for preparing such an optical article and to a method for repairing scratches in such an optical article by heating.