Antifog Optical Coating with Silicone Water-Repellent Layer
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Solution Overview
Problem
Conventional antifog coatings for optical articles, particularly those using water-absorbing layers, face challenges in maintaining visibility and durability due to surfactant loss, low slippage, and weather resistance, especially when exposed to water.
Innovation Solution
A water-absorbing layer primarily composed of urethane or acrylic resin with a polyoxyethylene chain is formed on a base material, followed by a water-repellent layer of amino-modified or mercapto-modified silicone, achieving a contact angle of 100 degrees or higher to enhance durability and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-absorbing layer is coated on a lens surface to prevent fogging, then antifog property is improved, but visibility is lowered when water-absorbing capacity is exceeded due to widened contact angle and light scattering
Solution Approach 1:
The antifog coating is divided into two functional layers: a water-absorbing layer (containing hydrophilic resin and surfactant) for fog prevention, and a water-repellent layer (containing fluorocarbon resin) for maintaining visibility. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between antifog property and visibility.
Solution Approach 2:
The coating uses a composite structure combining hydrophilic materials (for water absorption and antifogging) with hydrophobic materials (for water repellency and visibility maintenance). The composite material approach enables simultaneous achievement of antifog property and visibility by leveraging the complementary properties of different materials.
2Reliability
If surfactant is applied on lens surface to utilize wetting phenomenon, then antifog property is improved, but durability is reduced as surfactant comes off easily when wiped with water
Solution Approach 1:
The surfactant is incorporated into the water-absorbing layer during the coating formation process rather than being applied separately afterward. This preliminary incorporation ensures the surfactant is properly embedded and fixed in the coating matrix, preventing premature loss during wiping while maintaining its antifog function.
Solution Approach 2:
The surfactant is combined with hydrophilic resin and crosslinking agents in a composite water-absorbing layer. This composite structure provides a matrix that holds the surfactant in place, preventing it from coming off easily during wiping while maintaining the wetting phenomenon for antifogging.
3Reliability
If a water-absorbing layer is formed to prevent fogging, then antifog property is improved, but slippage and strength are reduced due to low surface slippage of water-absorbing materials
Solution Approach 1:
The coating is segmented into two layers with distinct functions: the water-absorbing layer provides antifogging, while the separate water-repellent layer provides surface strength and slippage. This segmentation allows optimization of each layer for its specific function without compromise.
Solution Approach 2:
The water-repellent layer acts as an intermediary protective layer on top of the water-absorbing layer. It provides the necessary surface strength and slippage properties, while allowing the underlying water-absorbing layer to perform its antifogging function. The intermediary layer protects the softer water-absorbing layer from mechanical damage.
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 effectively maintains antifog properties, improves visibility, and ensures high durability and weather resistance by forming a stable water-repellent layer on optical articles, even when wiped multiple times and exposed to water.
Implementation Method 1
coating a lens surface with water-absorbing resin
Implementation Method 2
a water-absorbing layer consisting primarily of urethane or acrylic resin having a polyoxyethylene chain
Implementation Method 3
a water-repellent layer consisting primarily of at least one of amino-modified silicone and mercapto-modified silicone is formed on a surface of the water-absorbing layer, and a contact angle with respect to water on a surface of the water-repellent layer is set equal to or larger than 100 degrees
Data Source
AI summary
[Problem to be Solved] To provide: an antifog optical article wherein a suitable water-repellent layer is formed in the process of application of antifog coating having a water-absorbing layer consisting primarily of urethane or acrylic resin having a polyoxyethylene chain on a base material; and a manufacturing method of the antifog optical article. [Solution] A water-absorbing layer consisting primarily of urethane or acrylic resin having a polyoxyethylene chain represented as - (CH2CH2O)n- is formed on a surface of a glass or plastic base material, a water-repellent layer consisting primarily of at least one of amino-modified silicone and mercapto-modified silicone is formed on a surface of the water-absorbing layer, and a contact angle with respect to water on a surface of the water-repellent layer is set equal to or larger than 100 degrees.