Tape Adhesive for High-Voltage Insulation Systems
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Solution Overview
Problem
The existing insulation systems for high-voltage electrical machines rely on anhydride-based impregnating resins, which pose health risks and require tape adhesives that are not inert enough, leading to storage stability issues with anhydride-free alternatives.
Innovation Solution
A tape adhesive composed of an addition product of bisphenol, diol, triol, and cyclohexene oxide derivatives, which reacts to form new hydroxyl groups, providing compatibility with anhydride-free impregnating resins and using accelerators that initiate anionic or cationic polymerization, ensuring stability and compatibility during the VPI process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anhydride-based impregnating resins are used, then reliable insulation performance is achieved, but health risks arise due to respiratory sensitization
Solution Approach 1:
The patent changes the chemical composition parameters of the impregnating resin by replacing anhydride-based formulations with oxirane-functional resins (epoxy resins). This substitution maintains the insulation performance while eliminating the respiratory sensitization hazards associated with anhydride compounds, directly resolving the contradiction between reliability and health safety.
2Stability of the object's composition
If conventional tape adhesives are used with anhydride-free impregnating resins, then storage stability is improved, but compatibility issues arise leading to premature gelation
Solution Approach 1:
The patent introduces a specifically designed tape adhesive as an intermediary component that is chemically compatible with oxirane-functional impregnating resins. This adhesive contains functional groups that do not trigger premature polymerization of the epoxy resin during storage, yet enable proper bonding and curing during the VPI process, thus resolving the contradiction between storage stability and insulation quality.
3Speed
If accelerator substances are added to initiate curing, then gelation speed is improved, but storage stability deteriorates due to premature reaction
Solution Approach 1:
The patent applies preliminary action by pre-coating the mica tape with an adhesive layer that is specifically formulated to be inert toward oxirane-functional resins under storage conditions. This preliminary preparation ensures that when the impregnating resin is later applied during VPI, the curing process can proceed at the desired speed without premature gelation, resolving the contradiction between gelation speed and storage stability.
4Strength
If the mica tape adhesive is made reactive with the impregnating resin, then bonding strength is improved, but storage stability of the tape deteriorates
Solution Approach 1:
The patent applies local quality by designing the tape adhesive with specific functional characteristics that differ from conventional adhesives. The adhesive contains functional groups that provide strong bonding to the mica tape substrate while being chemically inert toward the oxirane-functional impregnating resin during storage. During the VPI process, the local chemical environment changes to enable proper curing, thus resolving the contradiction between bonding strength and tape storage stability.
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 achieves long-term storage stability and compatibility with anhydride-free impregnating resins, ensuring defect-free insulation and extended electrical service life by controlling the reaction timing and networking of components during the impregnation process.
Implementation Method 1
having a dynamic viscosity of 1 - 100 Pas at impregnation temperature, comprising an addition product of a bisphenol, diol, triol and/or higher alcohol with cyclohexene oxide or a cyclohexene oxide derivative
Implementation Method 2
using accelerators that initiate anionic or cationic polymerization
Implementation Method 3
using accelerators that initiate anionic or cationic polymerization
Implementation Method 4
This achieves optimal cross-linking, bonding, compatibility, and ultimately, freedom from defects and voids
Data Source
AI summary
The invention relates to a tape adhesive for an insulating tape in an insulation system and to an insulation system, in particular an insulation system for electric machines in the high-voltage range from 1 kV, said tape adhesive having an anhydride-free impregnating resin, for example an impregnating resin having oxirane functionalities. By means of the invention, a tape adhesive for an insulation system, said tape adhesive being suitable for traditional impregnating methods and comprising solid insulating material such as mica, an anhydride-free impregnating resin, and an accelerator for the anhydride-free impregnating resin, is provided for the first time, wherein the tape adhesive is adjusted to the reactivity of an accelerator or curing catalyst of an anhydride-free impregnating resin with regard to the storage stability of the entire system.