Non-oriented Electrical Steel Sheet Coating Composition

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Solution Overview

Problem

Non-oriented electrical steel sheets face challenges in achieving high insulating properties, heat resistance, and corrosion resistance while maintaining weldability and adherence, especially as the coating thickness increases, which deteriorates other properties like stacking factor and heat resistance.

Innovation Solution

A non-oriented electrical steel sheet adhesive coating composition comprising a soluble epoxy resin with inorganic nanoparticles (SiO2, TiO2, or ZnO) and an inorganic additive like sodium hydroxide, where the nanoparticles are substituted in the terminal substituent group of the epoxy resin, providing a multifunctional epoxy resin with improved high temperature adhesive and oil-resistant properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coating thickness is increased to improve insulating property, then the insulating property between layers is improved, but the weldability, heat resistance, and stacking factor are deteriorated

Engineering Contradiction:
Improveinsulating propertyVSAvoidheat resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite coating composition containing epoxy resin, phenolic resin, and rubber particles. This multi-component composite system provides both excellent insulating properties and maintained heat resistance, resolving the contradiction between insulation and thermal performance that plagues single-material coatings.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the thickness parameter to a specific range (3-8 μm) and controls the composition ratios of coating materials. By precisely adjusting these parameters, the coating achieves high insulating property while maintaining adequate heat resistance and weldability, avoiding the deterioration that occurs with excessive thickness.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the coating thickness is increased to improve insulating property, then the insulating property between layers is improved, but the stacking factor is deteriorated

Engineering Contradiction:
Improveinsulating propertyVSAvoidstacking factor
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the coating thickness parameter to a specific range (3-8 μm) that provides sufficient insulation while minimizing the volume occupied by coating material. This precise parameter control ensures high stacking factor (above 97%) is maintained while achieving excellent insulating properties.

Inventive Principle:
Principle #35Parameter changes

3Strength

If conventional coupling methods are used to join steel sheets, then the structural integrity is improved, but the vibration and noise are increased

Engineering Contradiction:
Improvestructural integrityVSAvoidvibration and noise
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mechanical coupling methods (screws, welds, clips) with a chemical bonding system using the epoxy-phenolic-rubber coating composition. This coating creates a strong adhesive bond between steel sheets that eliminates mechanical contact points, thereby reducing vibration and noise while maintaining structural integrity.

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

Solution Approach 2:

The multi-component coating system (epoxy resin + phenolic resin + rubber particles) provides both strong adhesion for structural integrity and vibration-damping properties to reduce noise, replacing the need for conventional mechanical coupling methods.

Inventive Principle:
Principle #40Composite materials

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 enhances the insulating, anti-corrosive, and close-contacting properties, improves adherence, and maintains thermal resistance and oil-resistant properties, thereby improving motor efficiency and reducing vibration and noise by omitting conventional coupling methods.

Implementation Method 1

the inorganic nanoparticle is substituted in a terminal substituent group of the soluble epoxy resin

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

an insulating property, by which the performance of motor can be maximized by minimizing eddy current loss

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 3

high functionality (high insulating property, high heat resistance, and high corrosion resistance)

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Data Source

PatentEP3075882B1Composition for non-oriented electrical steel sheet, method of manufacturing non-oriented electrical steel sheet product, and non-oriented electrical steel sheet product
Publication Date: 2021.03.03 POHANG IRON & STEEL CO LTD
  • EP3075882B1 patent drawingFigure 1
  • EP3075882B1 patent drawingFigure 2

AI summary

A non-oriented electrical steel sheet composition, a manufacturing method of the non-oriented electrical steel sheet product, and a non-oriented electrical steel sheet product are provided, and the non-oriented electrical steel sheet composition includes a first composition including a soluble epoxy resin and an inorganic nanoparticle of SiO2, TiO2, ZnO, or combinations thereof, and an inorganic additive of phosphoric acid (H3PO4), sodium hydroxide (NaOH), or a combination thereof, wherein the inorganic nanoparticle is substituted in a terminal substituent group of the soluble epoxy resin, and the epoxy resin is a multifunctional epoxy resin in which there are three or more epoxy groups.