Sol-Gel Decorative Coating for Glass Cooktops

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Solution Overview

Problem

Decorative coatings on glass and glass-ceramic articles face challenges in achieving high temperature resistance, adhesion, scratch resistance, and impermeability to fluids and gases, particularly in high-stress environments like cooktops, where existing sol-gel processes often result in inadequate layer properties due to sensitive pigment composition ratios.

Innovation Solution

A sol-gel process using a specific ratio of platelet-shaped pigment particles and solid lubricants (10:1 to 1:1 by weight) within the decorative layer, combined with a curing process that forms a metal oxide network, enhances adhesion, impermeability, and scratch resistance, while allowing for various shades and optical effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a first coloring layer is applied directly to the transparent glass/glass-ceramic article, then adhesion and scratch resistance are improved, but tightness against the passage of liquid or gaseous media deteriorates

Engineering Contradiction:
Improveadhesion and scratch resistanceVSAvoidtightness against passage of liquid or gaseous media
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The coating system is divided into two separate layers: a first coloring layer applied directly to the substrate for adhesion and scratch resistance, and a second sealing layer applied over it for impermeability. This segmentation allows each layer to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite coating system combining two different material compositions: the first layer contains coloring substances and basic protective components, while the second layer contains sealing agents and impermeability-enhancing components. This composite structure achieves both mechanical strength and chemical/physical barrier properties simultaneously.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the decorative coating is designed for high temperature resistance, then thermal stability is improved, but adhesion strength deteriorates

Engineering Contradiction:
Improvetemperature resistanceVSAvoidadhesive strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The adhesion problem is segmented by creating a first coloring layer that provides strong bonding to the substrate at lower temperatures, and a second sealing layer that provides thermal stability. The first layer acts as an adhesive foundation while the second layer provides heat resistance, preventing the coating from tearing off during high-temperature operation.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If the coating composition includes sulfur oxides from gas combustion, then chemical resistance is improved, but adhesion strength and substrate integrity deteriorate

Engineering Contradiction:
Improvechemical resistance to sulfur oxidesVSAvoidadhesive strength and substrate integrity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The second sealing layer is specifically designed to convert the harmful effect of sulfur oxides into a beneficial protective barrier. The sealing layer contains components that react with or resist sulfur oxides, transforming the corrosive chemical environment into a controlled interface that protects both the substrate and coating from acid attack.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of manufacture

If the pigment composition ratio is not optimized, then manufacturing simplicity is improved, but layer properties such as adhesion and impermeability deteriorate

Engineering Contradiction:
Improvecoating application simplicityVSAvoidlayer properties including adhesion and impermeability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The pigment composition is segmented into two separate layers with different requirements: the first layer uses standard coloring pigments for aesthetic purposes, while the second layer uses specifically formulated pigments optimized for impermeability and chemical resistance. This segmentation allows each layer to have its pigment ratio optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

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 method produces decorative layers with superior adhesion, impermeability, and scratch resistance, maintaining stability under high thermal stresses and preventing optical changes, even after prolonged exposure to high temperatures, thus ensuring the integrity and appearance of glass and glass-ceramic surfaces.

Implementation Method 1

The functional glass-like layers are produced by hydrolysis and condensation, e.g. on the basis of a sol-gel process, from hydrolyzable silanes, organosilanes

Methodology Applied
Scientific EffectSol-gel process: Sol

Implementation Method 2

The functional glass-like layers are produced by hydrolysis and condensation

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

The functional glass-like layers are produced by hydrolysis and condensation

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

The coating of a mixture of these components is applied to a substrate and thermally consolidated into a vitreous layer

Methodology Applied
Scientific EffectThermal consolidation: Heating

Implementation Method 5

thermally consolidated into a vitreous layer

Methodology Applied
Scientific EffectVitrification: Vitrification

Implementation Method 6

solid lubricant in a certain weight percent ratio as decorative pigments

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP2141133B1Decorative coating for glass and ceramic-glass items
Publication Date: 2012.02.22 SCHOTT AG
  • EP2141133B1 patent drawingFigure 1~2

AI summary

In the production of decorative layers on glass or glass ceramic substrates by a sol-gel method, where decorative pigments and fillers are added to the sol and the mixture is hardened by firing to form the decorative layer, the decorative pigment component to be added is a combination of platelet-form pigment particles and solid lubricant in a weight ratio of 1-10:1 (preferably 1-5:1, especially 1.5-3:1). An independent claim is included for glass or glass ceramic articles with a decorative coating (preferably produced by the above process), comprising a glass or glass ceramic substrate with a decorative layer containing a hardened sol-gel binder (forming a metal oxide network), decorative pigments and optionally filler, where the decorative pigment component is as above.