Solid Insulation Material with Dual-Catalyst Epoxy Impregnation
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Solution Overview
Problem
Current insulation materials for medium- and high-voltage electrical machines face challenges with storage stability and impregnation efficiency due to the interplay between tape adhesives, curing catalysts, and impregnating agents, leading to suboptimal crosslinking and potential cavities in the insulation system.
Innovation Solution
A formulation using a low-viscosity cycloaliphatic epoxy resin with a first curing catalyst in the solid insulation material and a second curing catalyst in the impregnating agent, where the first catalyst is reactive with the epoxy resin but inert with the tape adhesive, ensuring storage stability and efficient impregnation, and the second catalyst activates at higher temperatures for complete curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a curing catalyst is added to the solid insulation material to accelerate impregnation, then impregnation efficiency is improved, but storage stability deteriorates due to premature reaction with the tape adhesive
Solution Approach 1:
The patent divides the curing catalyst into two separate components: a first curing catalyst incorporated into the solid insulation material and a second curing catalyst incorporated into the impregnating agent. This segmentation prevents premature reaction during storage while enabling complete curing during the impregnation process, thus resolving the contradiction between impregnation efficiency and storage stability.
Solution Approach 2:
The patent introduces a multi-catalyst system where the first curing catalyst (in the solid insulation material) and second curing catalyst (in the impregnating agent) work in sequence. The first catalyst initiates gelation during impregnation, while the second catalyst completes curing at higher temperatures, serving as an intermediary mechanism to achieve both storage stability and impregnation efficiency.
2Manufacturing precision
If a highly reactive curing catalyst is used to achieve complete curing, then crosslinking optimization is improved, but storage stability deteriorates due to premature gelation
Solution Approach 1:
The patent segments the curing catalyst functionality into two parts with different reactivity levels: the first curing catalyst provides initial reactivity for gelation during impregnation, while the second curing catalyst provides higher reactivity for complete curing at elevated temperatures. This segmentation allows optimization of crosslinking without compromising storage stability.
Solution Approach 2:
The patent changes the temperature parameter during the curing process, using the first curing catalyst at impregnation temperature for gelation and then activating the second curing catalyst at higher temperatures (above 100°C) for complete curing. This parameter change enables controlled crosslinking progression that maintains storage stability while achieving optimal crosslinking density.
3Productivity
If the impregnating agent is made more mobile for better penetration, then impregnation efficiency is improved, but gelation control deteriorates leading to premature gelation
Solution Approach 1:
The patent segments the gelation process into two stages controlled by different catalysts: the first curing catalyst in the solid insulation material provides initial gelation control as the mobile impregnating agent penetrates, while the second curing catalyst in the impregnating agent ensures complete gelation after penetration is complete. This segmentation maintains gelation control reliability even with highly mobile impregnating agents.
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
This approach results in a stable insulation system with optimized crosslinking, reduced cavities, and extended lifetime of the electrical machine insulation, while maintaining storage stability and achieving high glass transition temperatures without the use of acid anhydrides.
Implementation Method 1
the impregnating resin is a cycloaliphatic epoxy resin which reacts with a first curing catalyst deposited in the solid insulation material
Implementation Method 2
the second curing catalyst only lights off at higher temperatures, for example at above 100° C.
Implementation Method 3
the air in the cavities of the windings and especially in the groove gaps of the stator laminate stack is eliminated
Data Source
AI summary
The present disclosure relates to insulation. Various embodiments thereof may include a solid insulation material and/or a formulation for production of an insulation system. For example, a formulation for an impregnating agent may include: an impregnating resin comprising a cycloaliphatic epoxy resin having a viscosity of less than 1500 mPas at impregnation temperature; and a curing catalyst deposited in the solid insulation material. The curing catalyst may be reactive toward the cycloaliphatic epoxy groups of the cycloaliphatic epoxy resin in the formulation of the impregnating agent but be sufficiently reactively inert with respect to the functional groups of the tape adhesive likewise present in the solid insulation material to confer storage stability to the solid insulation material.