Polysiloxane-Modified Insulating Varnish for Wire Lubricity

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Solution Overview

Problem

Existing electrical insulating varnishes for wires lack sufficient lubricity, which hinders high packing density and efficient winding, leading to mechanical stress and suboptimal induction performance.

Innovation Solution

A modified electrical insulating varnish featuring a base polymer from polyamideimide or similar, combined with two different polysiloxanes of varying Si unit lengths, providing enhanced sliding properties and mechanical/thermal performance without external lubricants, achieved through specific viscosity and solids content adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional electrical insulating varnishes are used, then the wires can be coated with insulation, but the lubricity of the coated wires is insufficient

Engineering Contradiction:
ImprovelubricityVSAvoidmechanical and thermal properties
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies composite materials by combining a base polymer (polyamideimide, polyesterimide, polyester, polyamide, polyurethane, polyimide, polyesteramideimide, or polyepoxide) with two different polysiloxane modification units having different chain lengths. This composite structure provides both excellent lubricity from the polysiloxane components and maintains mechanical/thermal properties through the base polymer matrix, resolving the contradiction between ease of operation and reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by incorporating two different polysiloxane modification units with different chain lengths (10-30 weight% of total polymer) into specific positions within the polymer structure. The shorter-chain polysiloxane (65-110 Si units) and longer-chain polysiloxane (140-200 Si units) are distributed to create localized lubricating regions that enhance sliding properties while the base polymer maintains structural integrity and thermal-mechanical performance.

Inventive Principle:
Principle #3Local quality

2Productivity

If high packing density is achieved through improved sliding, then wire winding efficiency increases, but the varnish formulation becomes more complex

Engineering Contradiction:
Improvewinding speedVSAvoidvarnish formulation
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the number of silicon units in the polysiloxane modification units (shorter-chain: 65-110 Si units, longer-chain: 140-200 Si units) and their proportion (10-30 weight% of total polymer). These parameter optimizations enable high sliding properties and winding speeds while maintaining a manageable formulation complexity through defined compositional ranges rather than arbitrary combinations.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the varnish has high sliding properties, then wire damage during winding is reduced, but achieving sufficient lubricity compromises mechanical strength

Engineering Contradiction:
Improvesliding propertiesVSAvoidmechanical strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent uses composite materials where the base polymer provides mechanical strength and thermal stability, while the polysiloxane modification units (10-30 weight%) provide lubricating properties. This composite structure ensures that the coating has both excellent sliding properties to reduce wire damage and sufficient mechanical strength to protect the wire, resolving the contradiction between ease of operation and strength.

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 varnish enables high-speed winding with reduced friction, achieving high packing density and optimal induction performance while maintaining mechanical and thermal resistance, with self-structuring phase separation contributing to excellent sliding properties.

Implementation Method 1

self-structuring phase separation contributing to excellent sliding properties

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 2

The varnish enables high-speed winding with reduced friction, achieving high packing density and optimal induction performance while maintaining mechanical and thermal resistance, with self-structuring phase separation contributing to excellent sliding properties

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3168268B1Electro-insulating varnish and method for producing same
Publication Date: 2018.09.26 SCHWERING & HASSE ELEKTRODRAHT

AI summary

Electrical insulating varnish, particularly for coating wires, wherein the varnish comprises a base polymer from the group consisting of polyamide-imide, polyester-imide, polyester, polyamide, polyurethane, polyimide, polyester-amide-imide, and polyepoxide, the base polymer being modified with polymeric modification units in the form of at least two different polysiloxanes. The two polysiloxanes have different numbers of silicon units, with the number of silicon units in the longer-chain siloxane being 1.5 to 2.5 times greater than the number of silicon units in the shorter-chain polysiloxane. The longer-chain polysiloxane has 120 to 300 silicon units, and the shorter-chain polysiloxane has 50 to 150 silicon units. The viscosity of the ready-to-use varnish is 650 to 1500 mPa s.