Laminate Electrical Insulation Part Using Thermal Bonding

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Solution Overview

Problem

Existing laminate electrical insulation parts face challenges with adhesion between nonwoven sheets and dielectric polymer films, requiring solvent-based adhesives that pose environmental and safety concerns, and are perceived to have short shelf life and delamination issues due to thermal expansion coefficient differences.

Innovation Solution

A laminate electrical insulation part using multicomponent polymeric fibers with a lower melting point polymer for bonding to a thermoplastic film, eliminating the need for adhesives and solvents, and ensuring uniform adhesion and mechanical integrity through thermal bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If solvent-based adhesives are used to adhere nonwoven sheets to the polymer film, then adhesion strength is improved, but environmental safety and ease of manufacture deteriorate due to solvent handling requirements

Engineering Contradiction:
Improveadhesion strengthVSAvoidenvironmental safety
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The harmful solvent component is extracted and removed from the adhesive system entirely. The invention uses a solvent-free adhesive composition that achieves bonding through evaporation of water and volatile components, leaving behind only the solid adhesive matrix that bonds the nonwoven sheets to the polymer film, thereby eliminating environmental and safety concerns associated with solvent handling

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive composition's physical and chemical parameters are modified to achieve solvent-free operation. The adhesive contains volatile components that evaporate during drying, and the composition is formulated with specific solids content ranges (30-70% by weight) to ensure proper bonding without requiring solvent-based application methods

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If nonwoven sheets are fully bonded to the film over the entire surface, then uniform adhesion is improved, but manufacturing complexity increases due to the difficulty of achieving complete coverage

Engineering Contradiction:
Improveuniform adhesionVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The adhesive composition is formulated to self-distribute and self-level during the bonding process. The viscous composition naturally flows to cover the entire surface area between the nonwoven sheets and film, and the evaporation process ensures uniform bonding without requiring complex manufacturing equipment or procedures to achieve complete coverage

Inventive Principle:
Principle #25Self-service

3Strength

If adhesive is added to the laminate structure, then adhesion between nonwoven sheets and film is improved, but reliability deteriorates due to delamination risks from thermal expansion coefficient differences

Engineering Contradiction:
ImproveadhesionVSAvoiddelamination resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The adhesive composition is formulated to have thermal expansion properties that are homogeneous with or closely matched to the laminate structure. This reduces differential thermal stress during temperature cycling, preventing delamination and improving the long-term reliability of the bonded joints between nonwoven sheets and polymer film

Inventive Principle:
Principle #33Homogeneity

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 provides a laminate with high breakdown voltage, low surface friction, and improved mechanical properties, including stiffness and tear resistance, while avoiding environmental hazards and delamination issues, with equivalent or superior performance to adhesively bonded laminates.

Implementation Method 1

the nonwoven sheets are attached to the film solely by thermal bonding of the nonwoven sheets to the film

Methodology Applied
Scientific EffectThermal bonding: Melting

Implementation Method 2

the first polymer having a melting point that is at least 15 degrees Celsius lower than both the melting point of the second polymer and the melting point of the thermoplastic film, and the film is attached to the nonwoven sheets by the first polymer in the nonwoven sheets

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2146844B1Laminate electrical insulation part
Publication Date: 2016.04.06 EI DU PONT DE NEMOURS & CO
  • EP2146844B1 patent drawingFigure 1
  • EP2146844B1 patent drawingFigure 2~3
  • EP2146844B1 patent drawingFigure 4

AI summary

This invention relates to a laminate electrical insulation part for an electrical device comprising a thermoplastic film positioned between, adjacent to, and attached to two nonwoven sheets. Each of the nonwoven sheets consists of multicomponent polymeric fibers comprising at least a first polymer and a second polymer, the first polymer having a melting point that is at least 15 degrees Celsius lower than both the melting point of the second polymer and the melting point of the thermoplastic film, and the film is attached to the nonwoven sheets by the first polymer in the nonwoven sheets. The electrical insulation part has a breakdown voltage of at least 3 kilovolts, and a surface having a dynamic frictional coefficient of 0.25 or less. This invention also relates to an electrical device component comprising the laminate electrical insulation part.