Thermoformable Hardcoat Silane Composition for Flexible Coatings
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Solution Overview
Problem
Current hardcoating compositions for transparent thermoplastics are not suitable for demanding thermoforming applications due to lack of flexibility, leading to micro-cracking and reduced weatherability, as they are either too rigid or provide insufficient mar and abrasion resistance.
Innovation Solution
A thermoformable hardcoat composition comprising silane-containing oligomers, silanes, metal oxides, and a condensation catalyst, with a specific T3 to T2 ratio, that can be hydrolytically condensed to achieve flexibility, mar resistance, and weather resistance, while maintaining compatibility with other components and allowing for complex shape thermoforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional hardcoating compositions are used to improve abrasion resistance, then mar resistance is improved, but flexibility deteriorates leading to micro-cracking during thermoforming
Solution Approach 1:
The patent applies parameter changes by precisely controlling the T3/T2 ratio of silane components in the coating composition. By adjusting the molecular structure parameters of the silane oligomers and controlling the hydrolytic condensation process, the coating achieves optimal balance between flexibility and mar resistance, enabling successful thermoforming without micro-cracking.
Solution Approach 2:
The patent uses composite materials by combining silane-containing oligomers with specific T3/T2 ratios, metal oxides, and condensation catalysts. This composite approach creates a coating that integrates both flexibility (from controlled silane structure) and hardness/mar resistance (from metal oxide content), resolving the contradiction between these opposing properties.
2Adaptability or versatility
If difunctional silane is added to improve flexibility, then flexibility is improved, but weatherability deteriorates due to random deployment and stress
Solution Approach 1:
The patent controls the T3/T2 ratio parameter to ensure proper molecular structure of the silane network. This controlled structure allows flexibility without random crosslinking, and the resulting coating has reduced internal stress that would otherwise compromise weatherability. The parameter control ensures both flexibility and long-term durability.
Solution Approach 2:
The patent employs feedback by monitoring and controlling the T3/T2 ratio during coating formulation and application. This feedback mechanism ensures that the silane structure achieves the optimal balance between flexibility and weatherability, preventing the random deployment issues that plague conventional approaches.
3Adaptability or versatility
If colloidal silica with small particle size is used to improve flexibility, then flexibility is improved, but abrasion resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the T3/T2 ratio and silane oligomer structure rather than relying on colloidal silica particle size. This approach achieves flexibility through molecular structure control while maintaining abrasion resistance through proper crosslinking density, avoiding the trade-off inherent in using small particle size colloidal silica.
4Strength
If rigid hardcoating compositions are used to achieve hardness, then abrasion resistance is improved, but adaptability to thermoforming deteriorates
Solution Approach 1:
The patent resolves this contradiction by changing the structural parameters of the silane network through T3/T2 ratio control. The resulting coating has a molecular structure that provides both the hardness needed for abrasion resistance and the flexibility required for thermoforming, eliminating the need to choose between these properties.
Solution Approach 2:
The patent creates a composite coating system that combines controlled silane oligomers with metal oxides. This composite structure provides the hardness and abrasion resistance of metal oxides while the silane matrix maintains flexibility and thermoformability, resolving the contradiction between rigidity and adaptability.
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 composition provides a flexible cured coating with enhanced hardness, mar resistance, and weather resistance, exhibiting less than 20% delta haze after taber abrasion testing and greater than 5% strain without cracking or delamination, suitable for glazing and solar cell applications, meeting ANSI Z26.1 standards for automotive glazing.
Implementation Method 1
components (A), (B) and (C) are hydrolytically condensed in the presence of component (D) to achieve a T3 to T2 ratio of from about 0.3 to about 2.5
Data Source
AI summary
A coating composition suitable for providing a thermoformable hardcoat is disclosed. The composition contains a silane-containing oligomer (A), a silane (B) having the general formula R3cSiX(4-d) wherein each occurrence of R3 is independently a C1-C8 alkyl, C2-C8 alkenyl or C6-C20 aryl, each occurrence of X is a halogen atom, C1-C6 alkoxy, C1-C6 acyloxy, C1-C6 alkenoxy or hydroxide; d is 0, 1 or 2, a metal oxide (C) and a condensation catalyst (D) wherein components (A), (B) and (C) are hydrolytically condensed in the presence of component (D) to achieve a T3 to T2 ratio of from about 0.3 to about 2.5.