Insulating Paper Adhesive Protrusion Prevention

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Solution Overview

Problem

Insulating paper for oil-immersed motors used in folded states lacks sufficient prevention of adhesive protrusion, which is critical for maintaining performance and durability under high temperatures and oil immersion.

Innovation Solution

The insulating paper comprises a polyester film laminated with heat-resistant aromatic polyamide sheets using an acrylic adhesive containing polyisocyanate and polybutyl acrylate, with a specific weight ratio and molecular weight, to prevent adhesive protrusion and enhance heat resistance and oil resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a urethane adhesive is used to laminate heat-resistant paper to polyester film, then heat resistance and oil resistance are improved, but adhesive protrusion occurs when the insulating paper is strongly folded

Engineering Contradiction:
Improveheat resistanceVSAvoidadhesive protrusion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the adhesive by specifying precise proportions of polyisocyanate (more than 3 parts by weight and 20 parts by weight or less based on 100 parts by weight of polybutyl acrylate) and polybutyl acrylate with specific molecular weight (400,000 or more). This parameter optimization resolves the contradiction by achieving both heat resistance and prevention of adhesive protrusion during folding

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive system combining polyisocyanate and polybutyl acrylate in specific proportions. This composite material approach allows the adhesive to simultaneously exhibit heat resistance (from the crosslinked structure) and flexibility (from the polyacrylate component), preventing adhesive protrusion while maintaining thermal stability

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the insulating paper is used in folded state, then ease of installation is improved, but adhesive protrusion occurs compromising performance

Engineering Contradiction:
Improveease of installationVSAvoidperformance stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By optimizing the molecular weight of polybutyl acrylate to 400,000 or more and controlling the polyisocyanate content within specific ranges, the adhesive achieves optimal balance between flexibility (for folding during installation) and structural integrity (for maintaining performance stability after installation)

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If high molecular weight polybutyl acrylate is used in the adhesive, then adhesive protrusion is prevented, but processing difficulty increases

Engineering Contradiction:
Improveadhesive protrusion preventionVSAvoidprocessing difficulty
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent specifies precise parameter ranges for polyisocyanate (more than 3 parts by weight and 20 parts by weight or less based on 100 parts by weight of polybutyl acrylate) to balance the high viscosity of high molecular weight polybutyl acrylate. This controlled formulation maintains processability while achieving the desired adhesive protrusion prevention

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 effectively prevents adhesive protrusion, maintains tensile strength and dielectric breakdown voltage at high temperatures, and improves the processing and durability of the insulating paper, ensuring stable performance in severe operating conditions.

Implementation Method 1

the polyester film and the heat resistant sheets being bonded with an acrylic adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2938493B1Insulating paper for oil-immersed motors
Publication Date: 2019.11.20 NITTO SHINKO KK
  • EP2938493B1 patent drawingFigure 1
  • EP2938493B1 patent drawingFigure 2
  • EP2938493B1 patent drawingFigure 3

AI summary

There is provided insulating paper for oil-immersed motors used in an oil-immersed motor in a state where folding is applied to the paper, the motor operating in a state where it is immersed in a cooling oil, the paper including a polyester film and heat resistant sheets made from aromatic polyamide laminated to both front and back surfaces of the polyester film, the polyester film and the heat resistant sheets being bonded with an acrylic adhesive, wherein the acrylic adhesive contains polyisocyanate and a polybutyl acrylate having a weight average molecular weight of 400,000 or more in a proportion of the polyisocyanate of more than 3 parts by weight and 20 parts by weight or less based on 100 parts by weight of the polybutyl acrylate.