Low Surface Energy Hard-Coat Lens for Welding Visors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polycarbonate lenses used in personal protection equipment are prone to scratching, chemical fracture, and staining, which affects their durability and visibility, and existing hard-coat solutions do not adequately address stain resistance and cleanability.
Innovation Solution
A low surface energy hard-coat layer is applied to the lenses, comprising a reaction product of perfluoropolyether urethane with hydrolysable silane groups and a silsesquioxane-based hard coat composition, providing improved scratch, chemical, and stain resistance, as well as easy cleanability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective hard-coat composition is applied to polycarbonate lenses, then scratch resistance and chemical resistance are improved, but stain resistance and cleanability deteriorate
Solution Approach 1:
The patent applies a composite coating system consisting of a silsesquioxane-based hard-coat layer combined with a fluoropolymer topcoat. The hard-coat provides scratch and chemical resistance, while the fluoropolymer layer provides low surface energy for stain resistance and easy cleanability. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The coating system applies different functional properties to different layers of the coating structure. The lower hard-coat layer provides mechanical protection, while the upper fluoropolymer layer provides surface energy modification for stain resistance. This local differentiation of functional qualities allows simultaneous achievement of durability and cleanability.
2Reliability
If a protective hard-coat composition is applied to polycarbonate lenses, then chemical resistance is improved, but stain resistance deteriorates
Solution Approach 1:
The patent combines a silsesquoxane-based hard-coat composition with a fluoropolymer coating. The hard-coat layer provides chemical resistance by forming a protective barrier, while the fluoropolymer topcoat provides low surface energy that prevents paint and other materials from adhering to the lens surface, thereby providing stain resistance.
Solution Approach 2:
The fluoropolymer coating changes the surface energy parameter of the lens surface to a low value, which fundamentally alters the wetting and adhesion characteristics. This parameter change causes paint and other materials to bead up rather than spread and adhere, providing stain resistance while the underlying hard-coat maintains chemical resistance.
3Ease of operation
If solvents are used to clean stained lenses, then stain removal is improved, but hard-coat durability deteriorates
Solution Approach 1:
The fluoropolymer-coated surface provides self-cleaning properties by preventing paint and other materials from adhering in the first place. Contaminants remain on the surface as discrete beads that can be easily removed with mild cleaning agents or even rain, eliminating the need for aggressive solvent cleaning that would damage the hard-coat layer.
Solution Approach 2:
The low surface energy of the fluoropolymer coating converts what would normally be adhesive contamination into easily removable surface beads. This transforms the potential harm of staining into a beneficial easy-clean surface that repels contaminants rather than absorbing them.
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 low surface energy hard-coat layer prevents paint and chemicals from adhering to the lens, allowing for easy cleaning without solvents, extending the lens's service life and maintaining unobstructed vision.
Implementation Method 1
The hard-coat layer preferably exhibits low surface energy. The low surface energy hard-coat layer prevents paint and chemicals from adhering to the lens
Implementation Method 2
an additive that includes at least one of i) a perfluoropolyether urethane that includes hydrolysable silane groups
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A personal safety protective device that includes a lens and a support structure onto which the lens is secured. The lens includes a substrate and a hard-coat layer located on the substrate of the lens. The hard-coat layer has a low surface energy outer surface that is derived from a) an additive that includes at least one of i) a perfluoropolyether urethane that includes hydrolysable silane groups, and ii) an acrylate polymer that includes at least one perfluoropolyether moiety and at least one hydrolysable silane group, and b) a silsesquioxane-based hard-coat composition. The provision of such a lens on a personal safety protective device enables the lens to be durable to abrasion and to be easily cleaned without use of solvents that could shorten the service life of the lens.