Anti-fog Visor Coating Resolving Tackiness and Delamination

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Solution Overview

Problem

Existing anti-fogging visor coatings using hydrophilic polyurethanes suffer from tackiness, delamination, and compromised transparency and hardness, making them unsuitable for flexible composite visors.

Innovation Solution

A novel anti-fog coating composition comprising a cross-linkable network of three different polymers: an adhesive polymer, a hard polymer, and a hydrophilic polymer, which provides enhanced mechanical strength, adhesion, and transparency, preventing delamination and tackiness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrophilic polyurethane coating is used to provide anti-fogging effects, then anti-fogging performance is improved, but the coating becomes soft and tacky leading to delamination and sticking to surfaces

Engineering Contradiction:
Improveanti-fogging performanceVSAvoidcoating hardness and adhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite coating system consisting of multiple layers: a hydrophilic polyurethane layer for anti-fogging performance, a polyurethane acrylate layer for hardness and scratch resistance, and a silane-crosslinked polyurethane layer for adhesion. This multi-layer composite structure allows each layer to contribute its specific properties, resolving the contradiction between anti-fogging performance and coating strength

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition and crosslinking density of the polyurethane coating by incorporating silane groups and acrylate functionality. These parameter changes enable the coating to achieve both hydrophilicity for anti-fogging and crosslinked network structure for enhanced hardness and adhesion, eliminating the tackiness problem

Inventive Principle:
Principle #35Parameter changes

2Reliability

If hydrophilic polyurethane coating is used to improve anti-fogging properties, then anti-fogging performance is improved, but transparency and haze are negatively affected

Engineering Contradiction:
Improveanti-fogging performanceVSAvoidtransparency and haze
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies different functional properties to different layers of the coating system. The hydrophilic polyurethane layer provides anti-fogging performance, while the polyurethane acrylate layer provides optical clarity and scratch resistance. This local differentiation of quality allows the coating to achieve both anti-fogging performance and high transparency without compromising either property

Inventive Principle:
Principle #3Local quality

3Reliability

If hydrophilic polyurethane coating is used to provide anti-fogging effects, then anti-fogging performance is improved, but the coating sticks to various surfaces causing delamination

Engineering Contradiction:
Improveanti-fogging performanceVSAvoidcoating application and assembly
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces a silane-crosslinked polyurethane layer as an intermediary between the hydrophilic polyurethane anti-fog layer and the substrate. This intermediary layer provides excellent adhesion to the substrate while preventing the hydrophilic layer from sticking to other surfaces, thus facilitating easy coating application and assembly operations

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves excellent adhesion, non-tackiness, high transparency, and maintains anti-fogging performance under repeated flexing and humid conditions, addressing the limitations of traditional coatings.

Implementation Method 1

a crosslinkable network comprising an adhesive polymer, a hard polymer, and a hydrophilic polymer wherein the adhesive polymer, hard polymer, and hydrophilic polymer are different from one another

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

a crosslinkable network comprising an adhesive polymer, a hard polymer, and a hydrophilic polymer

Methodology Applied
Scientific EffectHydrophilicity: Hydrophile

Data Source

PatentEP3013921B1Flexible visor having Anti-fogging properties and Anti-fogging coating compositions
Publication Date: 2020.03.11 SAINT GOBAIN PERFORMANCE PLASTICS CORP
  • EP3013921B1 patent drawingFigure 1~2

AI summary

The present disclosure is directed to transparent composites having anti-fogging properties and anti-fog coating compositions for providing anti-fogging properties. The anti-fogging layers can contain an adhesive polymer, a hard polymer, and a hydrophilic polymer, wherein the adhesive polymer, hard polymer, and hydrophilic polymers are different. In further embodiments, composites are described including a substrate layer; a first adhesive layer; a first transparent layer; a second adhesive layer; a second transparent layer; and an anti-fog layer.