Sol-Gel Iron Sole Plate Coating Without Oxide Interlayers

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Solution Overview

Problem

Existing iron sole plates face challenges in achieving low-friction, abrasion resistance, and easy cleaning while being cost-effective and applicable to a wide range of metallic base materials, with existing coatings requiring additional oxide layers and complex processes.

Innovation Solution

A sol-gel process using a monolayer coating composed of a hydrolysis and polycondensation product of methyl triethoxy silane, tetraethoxy silane, a metal precursor, and water, catalyzed by alkali hydroxide, directly adhering to the metallic base without an interlayer, providing a glass-like coating with improved mechanical and abrasive resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional coatings like AI-TiN or Teflon are applied to iron sole plates, then low friction and non-sticking properties are achieved, but the coating process becomes complex and costly

Engineering Contradiction:
Improvelow friction and non-sticking propertiesVSAvoidcoating process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention changes the chemical parameters of the coating material by using silane-based precursors that undergo hydrolysis and condensation reactions. This transforms the coating mechanism from physical deposition to chemical bonding, achieving durable low-friction surfaces through a simplified single-step sol-gel process without requiring complex PVD, CVD, or multi-layer applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention extracts and eliminates the intermediate oxide layer that is traditionally required between the metal substrate and the final coating. By using silane-based coatings that can directly bond to metal surfaces, the complex multi-layer structure (metal/oxide/coating) is reduced to a simpler (metal/coating) structure, reducing process complexity while maintaining coating performance

Inventive Principle:
Principle #2Taking out (Extraction)

2Strength

If sol-gel technique is used with multiple coating layers and oxide interlayers, then abrasion resistance is improved, but the manufacturing process becomes more complex and time-consuming

Engineering Contradiction:
Improveabrasion resistanceVSAvoidmanufacturing time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The invention merges multiple separate coating steps and intermediate oxide layer formation into a single sol-gel coating process. The silane-based coating is applied directly to the metal surface and undergoes in-situ hydrolysis and condensation to form a dense, cross-linked network structure that provides abrasion resistance without requiring sequential application of multiple layers or intermediate treatments

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention performs preliminary chemical modification of the silane precursors before application, preparing them in a sol state that facilitates uniform coating formation. The silane molecules are pre-hydrolyzed to a controlled extent and mixed with catalysts and additives, so that upon application and subsequent heating, the condensation reaction proceeds rapidly to form the final durable coating in a single step

Inventive Principle:
Principle #10Preliminary action

3Area of stationary object

If a thick sol-gel coating layer (30-40 μm) is applied, then coverage is improved, but cracks may form due to inner tensions

Engineering Contradiction:
Improvecoating coverageVSAvoidcoating integrity
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The invention applies local quality control by creating a coating with non-uniform density and cross-linking density through the sol-gel process. The coating structure transitions from a more porous sol state at the application stage to a dense, cross-linked gel state after heating, with the network formation occurring progressively from the substrate interface outward. This gradient structure accommodates thermal stresses and prevents crack formation while maintaining adequate coverage

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses a thin film approach with optimized coating thickness and flexible cross-linked silane networks that can accommodate thermal expansion and contraction stresses. The sol-gel derived coating forms a flexible, adherent film that maintains integrity under thermal cycling, avoiding the crack formation associated with thick, rigid coatings

Inventive Principle:
Principle #30Flexible shells and thin films

4Device complexity

If sol-gel coating is applied without an oxide interlayer, then process complexity is reduced, but adhesion to the base material may be compromised

Engineering Contradiction:
Improveprocess complexityVSAvoidcoating adhesion
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The invention replaces the mechanical/physical bonding mechanism (through oxide interlayers) with chemical bonding mechanisms. The silane precursors contain functional groups that can chemically interact with metal surface oxides and hydroxyl groups, forming strong covalent Si-O-Metal bonds. This chemical bonding mechanism eliminates the need for separate oxide interlayer formation while maintaining or improving adhesion strength

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 high mechanical and abrasive resistance, low friction, and easy cleaning, with improved adhesion and durability, outperforming conventional coatings like AI-TiN and Teflon in abrasion and friction tests, and demonstrating compatibility with both aluminum and stainless steel base materials.

Implementation Method 1

a coating layer covering said ironing surface wherein the coating is a hydrolysis and polycondensation product of a composition comprising: methyl triethoxy silane (MTEOS), tetraethoxy silane (TEOS), a metal precursor, and water

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

a coating layer covering said ironing surface wherein the coating is a hydrolysis and polycondensation product of a composition comprising: methyl triethoxy silane (MTEOS), tetraethoxy silane (TEOS), a metal precursor, and water

Methodology Applied
Scientific EffectPolycondensation:

Implementation Method 3

Sol-gel concept is known as a process comprising typically application of hydrolysable precursors such as oxides and alkoxides and a following heat treatment to obtain mechanically stable coating material with an enhanced density and hardness

Methodology Applied
Scientific EffectSol-gel process:

Implementation Method 4

catalyzed by alkali hydroxide

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP2844785B1Low-friction, abrasion resistant and easy-to-clean composite iron sole plate
Publication Date: 2016.04.27 EKSEN MAKINE SANAYI & TICARET
  • EP2844785B1 patent drawingFigure 1~2
  • EP2844785B1 patent drawingFigure 3a~3b
  • EP2844785B1 patent drawingFigure 3c~3d

AI summary

The present invention relates to a composite iron sole plate coated using sol-gel process with hydrolysis and condensation products of silanes with a metal precursor. The selected silanes are MTEOS and TEOS which give improved and tailored coatings for iron sole plates along with a metal precursor. The invention also relates to a novel method of producing iron sole plates having this coating, as well as an iron having such sole plate. The coating composition, when applied to an iron sole plate, found to be improving surface characteristics in terms of low friction, abrasion resistance, shine prevention and ease of cleaning due to its chemical stability and flatness.