Impregnating Composition for Electrical Wound Items

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Solution Overview

Problem

Current methods for impregnating electrical wound items using radically polymerizable compounds result in high vapour pressure emissions, toxicity, and hazardous by-products due to thermal curing, and existing alternatives like blocked isocyanates have low molecular product emissions and poor impregnation quality.

Innovation Solution

A composition comprising 5-95 wt% of resins with nucleophilic groups, 0-70 wt% of amide group-containing resins, and 0-95 wt% of organic solvent or water, containing α-carboxy-β-oxocycloalkyl carboxylic acid amide groups, which can be cured using high-energy radiation and thermal treatment to provide excellent adhesive and penetration properties without hazardous emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radically polymerisable compounds with high vapour pressure monomers are used for impregnation and thermal curing is applied, then the wound items are fixed and maintained, but environmental problems arise, materials have unpleasant odour and high toxicity, and disposal is necessary

Engineering Contradiction:
Improvefixing of wound itemsVSAvoidtoxicity and environmental harm
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by using resins with nucleophilic groups (OH, NHR, SH, carboxylate, or CH-acidic groups) that react with isocyanate groups to form urethane linkages. This chemical parameter change eliminates the need for high-vapour-pressure monomers while maintaining curing effectiveness, thereby reducing toxicity and environmental harm.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite impregnation composition containing multiple resin components with nucleophilic groups combined with isocyanate-containing resins. This composite material approach creates a synergistic system that achieves reliable wound item fixation without the harmful emissions and toxicity associated with traditional radically polymerisable compounds.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If blocked isocyanates are used for impregnation, then molecular product emissions are reduced, but impregnation quality becomes very low

Engineering Contradiction:
Improvemolecular product emissionsVSAvoidimpregnation quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent modifies the chemical reactivity parameters by using isocyanate groups that react with nucleophilic groups in the resins. This parameter change enables controlled crosslinking reactions that achieve high impregnation quality while maintaining low molecular emissions, overcoming the limitations of blocked isocyanate systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replicates the beneficial low-emission property of blocked isocyanates while copying and improving upon their curing mechanism. By using isocyanate groups that react with multiple nucleophilic groups, the system achieves both low emissions and high impregnation quality, effectively copying the best features while eliminating the drawbacks.

Inventive Principle:
Principle #26Copying

3Reliability

If high-temperature thermal curing is applied, then the impregnating composition is cured, but energy consumption increases and the process becomes time-consuming

Engineering Contradiction:
Improvecuring of compositionVSAvoidenergy consumption for curing
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent substitutes the thermal curing mechanism with a chemical crosslinking mechanism. Instead of relying on high-temperature thermal energy to drive polymerization, the system uses ambient or moderate temperature chemical reactions between isocyanate groups and nucleophilic groups, thereby eliminating the need for energy-intensive thermal curing equipment and processes.

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

Solution Approach 2:

The impregnation composition is formulated to undergo self-crosslinking at ambient or moderate temperatures through the spontaneous reaction between isocyanate groups and nucleophilic groups in the resins. This self-service curing mechanism eliminates the need for external high-temperature energy input, reducing energy consumption and simplifying the curing process.

Inventive Principle:
Principle #25Self-service

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 offers excellent adhesive and penetration properties for electrical wound items, reducing material losses and defects, and eliminates hazardous emissions, allowing for efficient curing without the need for high-temperature thermal treatment alone.

Implementation Method 1

curing the composition for fixing the wound items... Additionally cured by high-energy radiation simultaneously with or after thermal curing

Methodology Applied
Scientific EffectHigh-energy radiation curing: Photopolymerisation

Implementation Method 2

Curing is achieved by application of heat at temperatures of above 100°C in an oven... Before or, preferably, after application, it is possible to produce an elevated temperature by passing an electrical current through the wound items

Methodology Applied
Scientific EffectThermal curing: Heating

Implementation Method 3

produce an elevated temperature by passing an electrical current through the wound items

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2222806B9Use of a compostion for fixing wound items
Publication Date: 2013.05.22 EI DU PONT DE NEMOURS & CO

AI summary

A process for fixing wound items having wire windings of electrical equipment with an impregnating composition comprising the steps of a) impregnating said wound items by applying the composition comprising (A) 5 to 95 wt%, preferably 5 to 60 wt%, of at least one resin with nucleophilic groups selected from the group consisting of OH, NHR, SH, carboxylate and CH- acidic groups, (B) 0 to 70 wt%, preferably 1 to 50 wt%, of at least one amide group-containing resin, and (C) 0 to 95 wt%, optionally 0.1 to 40 wt%, of at least one organic solvent and/or water, wherein the resins of component (A) and/or component (B) contain a-carboxy-ß-oxocycloalkyl carboxylic acid amide groups, the wt% based on the total weight of the coating composition, and b) curing the applied impregnating composition. The process according to the invention provides excellent adhesive properties to the wound items as well as an excellent shrinkage and penetration.