Silane-Polysiloxane Coating for Pyrolysis-Resistant Metal Surfaces

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Solution Overview

Problem

Existing coating systems for metal components in cooking appliances fail to provide adequate thermal stability, anti-corrosion, and anti-tarnish protection, often resulting in porosity, emissions, and unsatisfactory aesthetic outcomes when exposed to high temperatures and chemical stress during pyrolytic cleaning.

Innovation Solution

A sol-based coating solution composed of a mixture of silane and polysiloxane, alkali or alkaline-earth oxide/hydroxide, and optionally nanoscale SiO2 particles, which forms a dense, impermeable, and decorative layer through hydrolysis and condensation, preventing tarnishing and corrosion while ensuring mechanical stability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a glass coat is applied wet-chemically by means of a coating finish produced by the sol-gel process, then the small layer thickness minimizes the tendency to flake off, but the porosity of the hitherto known coats leads to diffusion of food constituents during pyrolysis, resulting in clearly visible staining of the coating

Engineering Contradiction:
Improvecoating adhesionVSAvoidstaining
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the coating system by introducing a specific silane-polysiloxane mixture with controlled ratios, and adjusting the water content and pH conditions during sol-gel processing. These parameter changes result in a coating with optimized pore structure that prevents food constituent diffusion while maintaining adhesion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system combining silane and polysiloxane components in specific ratios, forming a hybrid material structure that integrates the benefits of both materials: silane provides adhesion and network formation, while polysiloxane contributes to thermal stability and reduced porosity

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If one attempts to use inexpensive types of high-grade steel for components in the oven field, then the cost is reduced, but the steel tarnishes and/or severely corrodes when subjected to thermal stress

Engineering Contradiction:
ImprovecostVSAvoidthermal stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies a relatively thin coating layer (compared to bulk material modification) that provides protective functionality without requiring expensive stainless steel substrates. The coating acts as a sacrificial or protective barrier that can be applied cost-effectively to ordinary steel components

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

Solution Approach 2:

The patent creates a composite structure combining the steel substrate with the silane-polysiloxane coating layer, where the coating provides the thermal and chemical resistance properties that the base steel lacks, achieving reliable performance at lower material costs

Inventive Principle:
Principle #40Composite materials

3Reliability

If the coating thickness is increased to provide better protection, then the protective effect is improved, but the coating becomes more prone to cracking and defects during thermal cycling

Engineering Contradiction:
Improveprotective effectVSAvoidcoating integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the coating thickness parameter within a specific range and controls the sol-gel processing parameters (water content, pH, temperature) to achieve a coating that is thick enough for protection but maintains flexibility and adhesion to prevent cracking during thermal cycling

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 coating solution achieves a critical thickness that prevents staining and emissions, maintains mechanical stability, and provides long-lasting aesthetic appeal, with enhanced thermal stability up to 500°C and resistance to scratches and impacts.

Implementation Method 1

A sol-based coating solution composed of a mixture of silane and polysiloxane, which can be cured by hydrolysis and condensation on a substrate

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

A sol-based coating solution composed of a mixture of silane and polysiloxane, which can be cured by hydrolysis and condensation on a substrate

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

If one attempts to apply a glass coat wet-chemically by means of a coating finish produced by the sol-gel process

Methodology Applied
Scientific EffectSol-gel process: Sol

Implementation Method 4

the critical coating thickness being unsatisfactorily low, however. According to the invention, critical coating thickness is taken to mean the coating thickness up to which, after drying and densification of the coating system applied to the substrate

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS8003723B2Pyrolysis resistant coating finish
Publication Date: 2011.08.23 BSH HAUSGERATE GMBH

AI summary

A coating solution made from a mixture of at least one silane and at least one polysiloxane which can be hardened on a substrate by hydrolysis and condensation to give a coating on the substrate, wherein the at least one silane is of general formula RxSi(OR′)4-x and the at least one polysiloxane is of general formula [R2SiO]y or R3Si—(O—SiR2)Y—O—SiR3, where R independently=alkyl, aryl, arylalkyl, alkylaryl or H, Rprime independently=H, methyl, ethyl, n- or i-propyl, n-, iso-, sec.- or tert.-butyl, x=0 or 1 (for the first silane), x=0, 1, 2, 3 or 4 (for each further silane) and y=a whole number of at least 2, wherein the coating solution includes at least one alkali or earth alkali oxide or hydroxide.