Antifogging Epoxy Resin Layer for Automotive Glass

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Solution Overview

Problem

Existing antifogging articles and automobile glasses face challenges in achieving a balance between good antifogging properties, peel resistance, and maintaining a clear appearance without discoloration, as previous solutions often result in a trade-off between these factors.

Innovation Solution

An antifogging article and automobile glass design featuring a transparent base with an antifogging layer made of epoxy resin cured material containing silicon and aluminum atoms, along with a foundation layer that includes a silicon atom bonded with three electron-withdrawing groups, using a composition of water-soluble epoxy resin, aluminum compounds, and alkoxysilane compounds to enhance water absorption, abrasion resistance, and appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a water-absorbing resin layer is made thicker to improve antifogging property, then water absorbing property is improved, but stress between the resin and base increases causing peel resistance to deteriorate

Engineering Contradiction:
Improveantifogging propertyVSAvoidpeel resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention changes the chemical composition parameters of the resin by incorporating specific ratios of hydrophilic monomers (5-50 mass%), hydrophobic monomers (50-95 mass%), and crosslinking agents (1-20 mass%). This parameter optimization allows the resin to achieve sufficient water absorption capability while controlling expansion stress to maintain peel resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite resin system combining multiple components: hydrophilic monomers (e.g., polyethylene glycol diacrylate), hydrophobic monomers (e.g., polyethylene glycol dimethacrylate), and crosslinking agents. This composite approach balances water absorption with structural integrity, resolving the contradiction between antifogging property and peel resistance.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a curing agent or curing catalyst is blended to inhibit yellowing, then appearance is improved, but film properties such as abrasion resistance deteriorate

Engineering Contradiction:
Improveappearance qualityVSAvoidabrasion resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention optimizes the concentration parameter of yellowing-preventive additives, limiting them to 1-20 mass% of the total resin composition. This controlled parameter change prevents excessive yellowing while avoiding the degradation of film properties and abrasion resistance that would result from higher concentrations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies different functional components in specific proportions: hydrophilic monomers (5-50 mass%) for water absorption, hydrophobic monomers (50-95 mass%) for structural stability, and crosslinking agents (1-20 mass%) for network formation. This localized quality distribution ensures that appearance quality is improved without compromising abrasion resistance.

Inventive Principle:
Principle #3Local quality

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 provides an antifogging article and automobile glass with an antifogging time of eighty seconds or more in a 35°C steam test, low haze variation after Taber abrasion, and minimal yellowness index change after heat resistance testing, ensuring effective fog prevention while maintaining transparency and appearance.

Implementation Method 1

a water-absorbing resin expands to have a stress difference from the base when it absorbs water

Methodology Applied
Scientific EffectHydrophilic interaction: Hydrophile

Implementation Method 2

an antifogging layer made of an epoxy resin cured material

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

a foundation layer... having a structure in which a silicon atom and three electron-withdrawing groups are bonded

Methodology Applied
Scientific EffectThermal expansion control: Thermal Expansion

Data Source

PatentEP3351381B1Antifogging article and automobile glass
Publication Date: 2020.11.18 AGC INC
  • EP3351381B1 patent drawingFigure 1~3

AI summary

There are provided an antifogging article and automobile glass that not only satisfy a good antifogging property and abrasion resistance but also have a good appearance. An antifogging article includes: a transparent base; and an antifogging layer which is provided on the transparent base and which made of an epoxy resin cured material containing a silicon atom and an aluminum atom, wherein, in the antifogging layer, an antifogging time (T35) in a 35°C steam test as measured by a predetermined method is eighty seconds or more, a variation ΔH in haze after a Taber abrasion test stipulated in Japan Industrial Standard (JIS) R3212 is 4.0% or less, and a variation ΔYI in a yellowness index stipulated in JIS K7373 after the antifogging layer is kept at 100°C for 500 hours is 3 or less.