Sol-Gel Hybrid Coating for Glass Cooktops

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Solution Overview

Problem

Existing semi-transparent coatings for glass and glass ceramics used in cooking surfaces face challenges in achieving high scratch resistance and maintaining sharp, high-contrast displays while preventing a view into the device's interior, as they either scatter light or have low temperature stability and are expensive due to the use of precious metals.

Innovation Solution

A sol-gel hybrid polymer coating system with nanoparticles and nanoscale pigments/dyes is used, which absorbs little to no visible light, providing high scratch resistance and opacity, and can be applied in a locally structured manner using screen printing, incorporating inorganic SiO2 nanoparticles and specific pigments for improved temperature stability and display clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If coatings with high light absorption capacity and high scattering are used to achieve high opacity, then the view into the interior is prevented, but the displays become blurred and low-contrast

Engineering Contradiction:
ImproveopacityVSAvoiddisplay sharpness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the particle size parameter of the pigment from conventional sizes to nanometer range (1-200 nm, preferably 5-50 nm). This parameter change eliminates light scattering while maintaining absorption, thereby preventing interior views without blurring displays.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different properties to different parts of the coating system: nanoscale pigments for opacity without scattering, and specific binder compositions for adhesion and flexibility. This local differentiation of properties resolves the contradiction between opacity and display sharpness.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If precious metals are used for non-scattering coatings, then display sharpness and contrast are maintained, but the manufacturing cost increases significantly

Engineering Contradiction:
Improvedisplay sharpnessVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent replaces expensive precious metals with cheap inorganic nanoscale pigments (metal oxides, metal carbides, metal nitrides). These inexpensive materials achieve the same optical performance without the high cost of noble metals.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite coating material combining inorganic nanoscale pigments with organic or inorganic binders. This composite approach achieves precious metal-level performance at fraction of the cost by combining different material classes synergistically.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If organic paint systems based on polyurethane are used for semi-transparency, then application ease is improved, but scratch resistance and temperature stability decrease to around 140°C

Engineering Contradiction:
Improveapplication easeVSAvoidtemperature stability
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent develops hybrid polymer systems combining organic polymers with inorganic sol-gel matrices and nanoscale pigments. This composite structure provides both the application ease of organic systems and the high temperature stability of inorganic materials, exceeding 140°C limitation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the binder from purely organic polyurethane to hybrid systems containing sol-gel components and inorganic precursors. This compositional change enables temperature stability while maintaining processability.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If conventional pigments with grain size distribution are used, then color coverage is achieved, but light scattering occurs due to particles larger than 200 nm

Engineering Contradiction:
Improvecolor coverageVSAvoidlight scattering
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent strictly controls the particle size parameter of all pigments to the nanometer range (1-200 nm, preferably 5-50 nm). This uniform nanoscale parameter eliminates scattering from large particles while maintaining effective color coverage through high surface area to volume ratio.

Inventive Principle:
Principle #35Parameter changes

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 achieves a semi-transparent coating with high scratch resistance, preventing interior views while maintaining sharp, high-contrast displays, even at elevated temperatures, without the high cost of precious metals, by using a sol-gel hybrid polymer matrix with non-scattering nanoparticles and temperature-stable pigments.

Implementation Method 1

nanoparticles and nanoscale pigments and/or dyes, in particular organic dyes, are added to the matrix... non-scattering nanoparticles that absorb little or nothing in the visible wavelength range

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

The hybrid polymeric precursor can be reacted with a tetra-alkoxysilane in a hydrolysis and condensation reaction in the presence of H2O

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

The condensation reaction is preferably carried out at a pH of 5-1, preferably 3-1. HCl or para-toluenesulfonic acid can be used as the acid.

Methodology Applied
Scientific EffectCondensation reaction: Condensation

Implementation Method 4

The coating material can be applied by a printing process... According to a preferred embodiment, the printing process can be a screen printing process

Methodology Applied
Scientific EffectScreen printing deposition: Deposition (physical)

Implementation Method 5

After coating, the color layers can be thermally cured or UV cured

Methodology Applied
Scientific EffectUV curing: Photopolymerisation

Implementation Method 6

After coating, the color layers can be thermally cured or UV cured. If inorganic, ceramic ink is used, the coating can be burned in after printing at temperatures of >500°C, preferably >700°C

Methodology Applied
Scientific EffectThermal curing: Heat Treatment

Data Source

PatentEP2718239A1Semi-transparent coating material
Publication Date: 2014.04.16 SCHOTT AG

AI summary

The invention relates to a semi-transparent coating material for coating glass or glass-ceramic, and in particular a glass or glass-ceramic cooking surface. According to the invention, the coating material contains at least one sol-gel hybrid-polymer coating system that comprises a hybrid-polymer sol-gel-based matrix, or an inorganic sol-gel-based matrix, to which nanoparticles and nanoscale pigments and/or dyes are added. According to the invention, the coating material is additionally produced, as a screen-printable, dual-component coating with a hybrid-polymer base, from a mixture of a first and a second component mixture. The first component mixture comprises the hybrid-polymer, and the second component mixture comprises nanoparticles and nanoscale pigments.