Adhesive Coating Composition for Electrical Steel Sheets

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Solution Overview

Problem

Existing adhesive coating compositions for electrical steel sheets deteriorate in high-temperature stress relief annealing processes, leading to loss of adherence and surface characteristics such as insulation, corrosion resistance, and adhesion.

Innovation Solution

An adhesive coating composition comprising 15-70 wt% of an organic resin and organic/inorganic composite with inorganic nanoparticles, 20-80 wt% of metal phosphate and phosphoric acid, and 1-10 wt% of a coupling agent, which forms a thermally-bonded layer between electrical steel sheets, maintaining bonding force even after stress relief annealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If organic adhesive coating composition is used for bonding electrical steel sheets, then bonding force is initially achieved, but adherence deteriorates after stress relief annealing process due to decomposition of organic material at high temperature

Engineering Contradiction:
Improvebonding forceVSAvoidadherence after stress relief annealing
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive coating by incorporating specific inorganic materials (metal phosphates, colloidal silica, water glass) that remain stable at high temperatures during stress relief annealing, replacing or supplementing organic materials that decompose at these temperatures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive coating system combining organic resins with inorganic materials (metal phosphates, colloidal silica, water glass, and other inorganic compounds) to achieve both initial bonding strength and high-temperature stability during stress relief annealing

Inventive Principle:
Principle #40Composite materials

2Strength

If low melting point glass frit or water glass is used as inorganic component, then bonding is achieved, but compatibility with thermoplastic resins is poor and bonding force deteriorates rapidly due to resin decomposition after stress relief annealing

Engineering Contradiction:
Improvebonding forceVSAvoidcompatibility and bonding stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical composition by selecting specific metal phosphates (calcium, zinc, magnesium, aluminum, cobalt) and controlling their particle size, distribution, and concentration to achieve optimal compatibility with thermoplastic resins and maintain bonding stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses coupling agents as intermediary substances that facilitate bonding between the inorganic metal phosphate particles and the organic thermoplastic resin matrix, improving interfacial adhesion and preventing rapid bonding force deterioration

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If conventional fastening methods (welding, clamping, interlocking) are used instead of adhesive coating, then structural strength is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvestructural strengthVSAvoidfastening method complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces mechanical fastening systems (welding, clamping, interlocking) with a chemical bonding system using adhesive coating composition, simplifying the manufacturing process while maintaining structural integrity of the electrical steel sheet laminate

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 enhances oil resistance, close contacting properties, corrosion resistance, and insulation, while improving adherence and magnetic properties of electrical steel sheets without requiring conventional fastening methods like welding or clamping.

Implementation Method 1

an adhesive coating composition... which forms a thermally-bonded layer between electrical steel sheets

Methodology Applied
Scientific EffectThermal bonding:

Implementation Method 2

stress relief annealing process that restores the magnetic characteristic by removing the processing stress of the steel sheet

Methodology Applied
Scientific EffectStress relief annealing: Annealing

Implementation Method 3

1 to 10 wt % of a coupling agent

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS12018181B2Adhesive coating composition for electrical steel sheet, electrical steel sheet laminate and method for manufacturing electrical steel sheet product
Publication Date: 2024.06.25 POHANG IRON & STEEL CO LTD

AI summary

An exemplary embodiment of the present invention provides: an adhesive coating composition enabling adherence (coupling) of an electrical steel sheet without using conventional coupling methods such as welding, clamping, and interlocking; an electrical steel sheet laminate to which the same is applied; and a method for manufacturing the same.An adhesive coating composition for an electrical steel sheet, according to an exemplary embodiment of the present invention, includes, on the basis of 100 wt % of total solids: 15 to 70 wt % of a first composition containing an organic resin and an organic/inorganic composite in which inorganic nanoparticles are substituted for an organic resin; 20 to 80 wt % of a second composition containing a metal phosphate and phosphoric acid; and 1 to 10 wt % of a coupling agent.The coupling agent may contain one or more of a silane-based coupling agent, a titanate-based coupling agent, and an aluminate-based coupling agent.