Perfluoropolyether Hardcoat for Polycarbonate Substrates
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Solution Overview
Problem
Existing optical display hardcoats face challenges in providing durable, stain-repellent, and easy-to-clean surfaces while maintaining transparency and resistance to abrasion and solvents, particularly on substrates like polycarbonate and acrylic that are prone to swelling or cracking with conventional solvents.
Innovation Solution
A polymerizable composition comprising a perfluoropolyether urethane material with ethylene oxide repeat units and a non-fluorinated binder precursor, combined with inorganic oxide particles, is applied to form a surface layer that is photocurable and provides a tough, abrasion-resistant, and stain-repellent coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional solvents are used in hardcoat formulations, then the coating can be applied to substrates, but the substrates (polycarbonate and acrylic) are prone to swelling or cracking
Solution Approach 1:
The patent changes the solvent parameter from conventional organic solvents to alcohol-based solvents, which have different chemical properties that prevent substrate swelling and cracking while still allowing proper coating application and curing
Solution Approach 2:
The perfluoropolyether urethane material acts as an intermediary component that bridges the solvent and substrate interaction, providing a coating formulation that is compatible with alcohol-based solvents and protects the substrate from damage
2Reliability
If hardcoat formulations use conventional binder precursors, then the coating can be cured, but the surface lacks stain-repellent properties and easy cleanability
Solution Approach 1:
The patent creates a composite coating system combining perfluoropolyether urethane material with inorganic oxide particles and alcohol-based solvents, where the perfluoropolyether component provides stain-repellent properties and easy cleanability while the inorganic particles provide durability
Solution Approach 2:
The perfluoropolyether urethane material provides localized fluorinated properties at the coating surface that specifically enhance stain resistance and cleanability, while the bulk coating maintains structural integrity and durability
3Strength
If inorganic oxide particles are added to hardcoat, then abrasion resistance improves, but the coating complexity increases
Solution Approach 1:
The perfluoropolyether urethane material serves multiple functions simultaneously: it acts as a binder for inorganic oxide particles, provides stain-repellent properties, ensures compatibility with alcohol-based solvents, and contributes to coating durability, thereby simplifying the overall formulation despite the presence of multiple components
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 results in a surface layer with enhanced durability, low lint attraction, and easy cleanability, maintaining optical clarity and resistance to scratches and solvents, with improved compatibility with alcohol-based solvents that do not cause substrate damage.
Implementation Method 1
a perfluoropolyether (e.g. urethane) material comprising at least two free-radically polymerizable groups
Implementation Method 2
at least one free-radically polymerizable groups and at least one photoinitiator
Data Source
AI summary
Presently is described a free-radically polymerizable composition comprising a mixture of reaction products of i) at least one polyisocyanate; ii) at least one isocyanate reactive perfluoropolyether compound; iii) at least one isocyanate reactive compound comprising greater than 6 repeat units of ethylene oxide; and iv) at least one isocyanate reactive non-fluorinated crosslinker comprising at least two free-radically polymerizable groups.