Oleophobic-Hydrophobic Polymer Layer for Electric Machine Protection
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Solution Overview
Problem
Existing polymer-based potting compounds and adhesive structures for electric machines are prone to degradation due to moisture and oil penetration, leading to corrosion, swelling, and loss of mechanical properties, particularly in oil-cooled electric motors.
Innovation Solution
A polymer-based layer structure with an oleophobic-hydrophobic surface is developed, comprising a first layer of polymer, a second layer with fluoropolymer particles, and an outer layer with a fluorocarbon compound having functional groups, which creates a nanostructured surface that repels both water and oils, enhancing hydrophobicity and oleophobicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone-based potting compounds are used to provide mechanical protection and electrical insulation, then high thermostability and oxidation stability are achieved, but the material absorbs oil and swells, leading to loss of mechanical properties
Solution Approach 1:
The patent applies a dual-layer surface treatment where only the outer surface of the silicone potting compound receives the fluorocarbon coating, while the bulk material retains its original silicone properties. This localized modification allows the interior to maintain high thermostability and oxidation stability, while the exterior surface gains oil-repellent properties through the fluorocarbon layer with water contact angles exceeding 120 degrees.
Solution Approach 2:
The invention creates a composite structure combining silicone base material with fluorocarbon surface coating. The silicone provides mechanical protection, electrical insulation, and thermal stability, while the fluorocarbon layer contributes oil repellency. This composite approach resolves the contradiction by integrating materials with complementary properties rather than relying on a single material to provide all functions.
2Strength
If adhesive structures are used to join components, then mechanical bonding is achieved, but moisture penetration causes corrosion and decomposition, destroying the adhesive bond
Solution Approach 1:
The fluorocarbon coating is applied specifically to the adhesive structure's exposed surfaces where moisture contact occurs, while the bonded interfaces maintain their original adhesive properties. This localized protection allows the adhesive bond to achieve strong mechanical joining while the coated surfaces resist moisture penetration that would otherwise cause corrosion and decomposition.
Solution Approach 2:
The hydrophobic fluorocarbon coating is applied to the adhesive structure before the adhesive bond is put into service, creating a pre-established moisture barrier. This preliminary protective action prevents moisture from penetrating the adhesive structure and causing subsequent corrosion, decomposition, and bond failure, thereby preserving adhesive strength over time.
3Object-affected harmful factors
If conventional polymer coatings are applied for protection, then basic corrosion resistance is provided, but they lack sufficient hydrophobicity and oleophobicity to prevent media penetration
Solution Approach 1:
The patent fundamentally changes the surface energy parameters of the polymer coating by introducing fluorocarbon groups, which have extremely low surface energy. This parameter change transforms the surface from hydrophilic to hydrophobic with water contact angles exceeding 120 degrees, and simultaneously provides oleophobicity, creating a dual-repellent surface that effectively prevents both water and oil media penetration while maintaining underlying corrosion resistance.
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 oleophobic-hydrophobic surface significantly reduces oil absorption and swelling, maintaining mechanical properties and adhesive strength, even in contact with oils, thereby extending the longevity of polymer structures in electric machines.
Implementation Method 1
the fluorocarbon sections of this compound, together with the polymer basic material of the lower layers, concurrently give rise to a strong hydrophobicity (water-repellent effect)
Implementation Method 2
Due to the reactive groups of the fluorocarbon compound of the outer layer, on the hand, an oleophobic (oil-repellent) surface is created
Implementation Method 3
the fluoropolymer particles of the second layer and, if applicable, of the outer layer, have two different functions. First of all, they serve as coupling agents between the first polymer layer and the outer layer. Secondly, the particles give rise to a certain structuring of the surface, especially a nanostructure, which increases the oleophobicity as well as the hydrophobicity
Data Source
AI summary
A polymer-based layer structure with an oleophobic/hydrophobic surface for coating, sealing, and/or connecting technical components or parts of said components, comprising—a first layer which comprises a polymer, —a second layer that adjoins the first layer and comprises a polymer and particles which comprise a fluoropolymer and which are distributed in the silicone, and —an outer layer that adjoins the second layer and comprises a fluorocarbon compound with at least one reactive group and optionally particles which comprise a fluoropolymer and which are distributed in the fluorocarbon compound. The invention also relates to an electric machine which has the layer structure, said layer structure being provided in particular as a potting compound on a winding and/or on switching rings of the stator and/or as a magnet bonding adhesive of the rotor.