Formulation for an insulation system, use of same and moulded body

Abstract

The invention relates generally to the field of insulation, more particularly to a formulation for a high-temperature insulation at operating temperatures of 200°C and higher. The insulation is used to insulate electric conductors. The invention thus relates to an insulation system for an electric machine, more particularly a rotating electric machine with a stator, such as an electric motor and / or a generator with improved temperature resistance of the polymer insulation system components and / or an insulating coating for generatively manufactured conductors or parts thereof, busbars, connecting bars and / or terminal boxes. The present invention discloses for the first time a compound, powder coating and / or formulation for a wet coating, which comprises high-performance thermoplastics as fillers, wherein it has been shown that these fillers can considerably increase the thermal resistance and provide even better thermomechanical properties in an insulation system produced therefrom.

Description

[0001] Description

[0002] Formulation for an insulation system, use therefor and shaped body

[0003] The invention relates generally to the field of insulation, in particular to a formulation for high-temperature insulation at maximum operating temperatures of up to 200 °C and more. The formulation, in the form of the shaped body obtainable therefrom by curing, serves as an insulation system, as an insulating coating for electrical conductors and / or as a part thereof. Thus, the invention also relates to a shaped body which is at least part of an insulation system for an electrical machine, in particular a rotating electrical machine with a stator, such as an electric motor and / or a generator, with improved temperature resistance of the polymeric insulation system components.The invention also relates to a shaped body as part of an insulating coating or as a whole forming an insulating coating, in particular the insulating coating of - for example - electrical conductors produced in an additive process, of busbars, of connecting rails and / or the insulating coating of terminal boxes.

[0004] Electrical machines for drive systems generally are equipped with a stator, as in medium- and high-voltage motors and generators, and include electrical conductors, main insulation, conductor insulation (such as wire insulation with partial conductor insulation), and the stator core. The main insulation serves the purpose of electrically insulating the phases from each other, from the grounded stator core, and from the environment.

[0005] The conductor insulation insulates the coil conductors from each other. Electrical machines are generally operated at the highest possible current densities. Traction motors operate at high temperatures—e.g., the thermal class of polymer-based plastics can reach up to 220°C. Therefore, the polymer plastics suitable for this purpose are limited to a few types.

[0006] A wound insulation system, on the other hand, includes not only surface insulation materials and / or insulating tapes, but also impregnating resin. Due to a wide variety of requirements, the surface insulation materials—which, for example, form the slot lining and / or the insulating tapes—are based primarily on mica and glass, but also on m-aramid and / or polyimide. Due to their high thermal performance and low processing temperature, thermosets with polyesterimide and / or silicone are typically used as impregnating resin in traction motors. Epoxies are typically used in industrial high-voltage motors.

[0007] In insulation systems with mica tapes, the paper is combined with a glass fabric carrier and / or a PET and / or PI film and cut into narrow rolls, which then form the insulation tapes and are wound - e.g. around the conductor or the coil.

[0008] For extruded conductor insulation and / or braided, tape-like conductor insulation – less so for solvent-based wire enamels – PEEK, PI, PAI, PPS, PEI, polyesterimide (thermosetting resins), and similar synthetic resins are conventionally used. Thermosetting wire enamels, which have been optimized for PD resistance, are particularly commercially available for conductor insulation.

[0009] Hairpin technology is a winding technology for stators in electric motors and generators, which represents a subgroup of wave windings. It is used particularly in traction motors for electric vehicles. In contrast to pre-formed coil winding technology, wave winding technology is based on wire windings which are inserted individually and not combined as coils into the stator slots of the laminated core. These plug-in coils, so-called hairpins, corrugated hairpins (“continuous hairpins”) and / or I-pins are wave-shaped, U- or I-shaped, varnished and / or extruded flat copper wires.

[0010] I-pins, for example, are straight-lined flat copper wires. With the "Continuous Hairpin" wave winding concept, so-called winding mats are manufactured and then inserted into the laminated core from the inside. Compared to U-pin and I-pin technology, this requires significantly less effort in the connection technology of the individual pins.

[0011] The design of a hairpin stator differs from conventional stators only in the type of winding system; the other components of the stator remain largely unchanged. The windings, in the form of insulated winding wire, are realized in the hairpin stator using plug-in coils.

[0012] Hairpin technology, a modern technology for stators in electrical machines, is testing new, more cost-effective methods. The flat copper wire with typical hairpin geometry is inserted into the slots of the laminated core using a forming-based assembly process. However, it is essential to insulate the soldered or welded connections between the individual hairpins with a coating, as these are not protected by the conductor insulation. The thermal resistance of the varnishes currently used is limited to temperature class 180 (H). To produce the finished insulation system, the winding, wire and / or hairpin is preferably also fixed in the slot by casting, impregnating, dripping, dipping and / or injection molding with a synthetic resin.On the other hand, a partial conductor insulated by wire extrusion can be fixed in the groove by injection molding.

[0013] There is still a need for an improved technology for a formulation for producing an insulation system and / or an insulating coating, in particular also suitable for the above-mentioned applications - also for use in plug-in coil and / or wave winding technology - for example applicable e.g. in traction motors for rail vehicles, passenger cars, trucks and / or for insulating coating, for example of terminal boxes, additively manufactured conductors and / or coils, as well as power or connecting rails.

[0014] The object of the present invention is therefore to provide a formulation for an insulating coating and / or an insulation system for an electrical rotating machine, in particular for use at maximum operating temperatures of more than 170 ° C, in particular of 200 ° C and above, preferably even of a maximum of 220 ° C and above, which is also suitable for use in plug-in coils and / or wave winding technology.

[0015] This object is achieved by the subject matter of the present invention as disclosed in the claims, the description and the examples.

[0016] The invention therefore relates to a formulation for an insulation system and / or an insulating coating, in the form of a casting, powder coating and / or solvent-containing wet coating, comprising at least one component B, wherein component A, an uncrosslinked, liquid or solid base resin with the hardener and / or accelerator required for curing, is also preferably contained, and component B is in the form of a PFT, i.e. in the form of a polymeric filler which is solid at room temperature under normal conditions and has a high relative temperature index, in particular greater than 160 ° C, wherein component A is present in the range from 0% to 99% by mass and component B is present in the range from 1% to 100% by mass, based on 100% of the solvent-free formulation.

[0017] The present invention also relates to a shaped body obtainable by curing the formulation described above, wherein the shaped body forms an insulation system or parts of an insulation system and / or an electrically insulating coating or parts of an electrically insulating coating.

[0018] Finally, the invention relates to the use of a formulation as described above for producing an insulation system, an insulating coating and / or a conductor insulation by powder coating, fluidized bed coating, wet painting and / or potting.

[0019] The "relative temperature index" here refers to the relative temperature index according to IEC 60216 or DIN EN 60216 "TI". This corresponds to the numerical value of the temperature in °C, which is derived from the long-term thermal relationship for a period of 20,000 hours at 5% mass loss.

[0020] After curing, a formulation according to the invention forms an insulation system in the form of a conductor insulation and / or parts of a conductor insulation. The formulation is processed, for example, but not exclusively, by means of powder coating, potting, fluidized-bed, and / or wet coating of conductors, parts of conductors, and / or housings. Curing to form the shaped body is preferably carried out thermally and / or via radiation, in particular UV curing.

[0021] A molded body made from the formulation can then, for example, partially or completely form the insulation of one or more individual rods, of the winding head and / or of the switching area of ​​a winding head and / or even the insulation of an entire wire winding. It can also function as partial conductor insulation and / or as individual rod insulation of a plug-in coil, of another conductor element using wave winding technology, and / or as an insulating coating of a generatively, in particular additively, manufactured conductor element.

[0022] Finally, the formulation may represent, in whole or in part, an insulating coating of current and / or connecting rails and / or terminal boxes.

[0023] Conductor insulation is, for example, the electrical insulation of the individual conductor turns of a coil against each other and / or the conductors of a wire winding and / or against the environment and / or against ground, e.g. of the electrical machine.

[0024] Fluidized-bed coating is the coating of a conductor in a fluidized bed filled with a powder coating formulation. In this process, a powder made of compounds that are solid under normal conditions is used. This means that, in addition to the thermoplastic, which is already solid in particle form, the base resin is also preferably in solid form.

[0025] Powder coating, in particular electrostatic powder coating, is carried out by spraying and / or using a fluidized bed process, for example. A powder made of solids is used, which means that in addition to the thermoplastic, which is already solid in particle form, the base resin is also present as a solid. Wet painting is carried out by, for example, painting, brushing, dipping, spraying, spin coating and / or dipping processes. The formulation is applied to the conductor in a solution in a solvent. The solvent is then at least partially removed and the formulation is cured. The base resin can be in solid and / or liquid form.

[0026] Casting is carried out with a liquid formulation without solvents, whereby the base resin, in contrast to the formulation which is used as a powder coating, is present as a liquid under normal conditions.

[0027] "Normal conditions" - a particularly relevant aspect with regard to processing conditions and storage stability - are defined as 25 °C room temperature, ambient air and normal pressure.

[0028] The general finding of the invention is that in a formulation for a casting, as a fluidized bed powder, as a powder coating and / or for a wet coating for producing an electrical insulation system and / or an insulating coating, the incorporation of solid and polymeric plastic filler particles with a high relative temperature index, polymer filler with a high relative temperature index "PET", brings advantages with regard to thermomechanical stability and in particular with regard to temperature stability.

[0029] This is particularly advantageous when the power density of the electrical conductors is increased, because an increase in power density always also results in an increase in operating temperatures.

[0030] The PFTs according to the invention have a high temperature index "TI", which is in particular above 160 ° C, preferably above 170 ° C, particularly preferably above 180 ° C and very particularly preferably above 190 ° C. PFTs with a high glass transition temperature are preferably used. This is particularly the case with thermoplastic, elastomeric and / or thermosetting particles with a glass transition temperature greater than or equal to 130 ° C, preferably greater than or equal to 150 ° C, preferably in a mixture with component A, with a base resin, hardener and / or accelerator that is still uncrosslinked, where the presence of PFTs achieves clear mechanical and / or thermomechanical advantages and / or a significant increase in the temperature resistance of the resulting insulation system and / or the insulating coating.

[0031] The thermoplastic, elastomeric, and / or thermosetting PFTs of component B are identical or different, for example, with regard to material, surface treatment, surface coating, crystallinity, amorphousness, grain size, particle shape, and / or fiber reinforcement. The PFTs are preferably deagglomerated.

[0032] Component B contains the PFTs and is present in the dry formulation in a mass fraction based on 100 parts by mass of solvent-free formulation in the range from 1% to 99% by mass, in particular from 10% to 60% and very particularly preferably from 20% to 50% and particularly preferably in the range from 20% to 30% by mass based on 100 parts by mass of solvent-free formulation.

[0033] The "base resin" with, if necessary, hardener, accelerator, additives, supplements, and other fillers then forms the remainder of the 100% by mass of the solvent-free formulation.

[0034] The term “base resin” in the sense of “main constituent of the formulation” no longer applies according to this invention because, if component B represents more than 50% by mass of the formulation, the resin is sometimes only used as a binder or, for example, in a powder coating formulation, not used at all. According to an advantageous embodiment of the invention, the base resin is present in the formulation as component A in the form of a not yet crosslinked thermoset resin which comprises one or more compounds selected from the group consisting of epoxy resin, polyurethane resin, polyisocyanate resin, polyimide resin, polyesterimide resin and / or polyester resin in any desired mixtures, blends and / or copolymers. For example, the thermoset uncrosslinked synthetic resin in the formulation comprises compounds such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, novolak, aliphatic epoxy resin and / or aromatic epoxy resin.When used solvent-free as a casting compound and / or as a solvent-containing wet paint, the base resin can be liquid even under normal conditions; when used as a powder paint, it is a powder, i.e. a solid.

[0035] For this purpose, component A contains a hardener corresponding to the base resin, i.e. in a stoichiometrically suitable amount and chemically matching to the base resin, which is based, for example, on anhydride, imidazole, bisphenol and / or dicyanamide.

[0036] To initiate the curing after application - e.g. spraying of the powder coating - of the formulation onto the body to be insulated, for example a plug-in coil in hairpin technology, component A can also contain an accelerator in a small amount, e.g. in the range from 0.3 to 2% by mass. Accelerators for this application are known to the person skilled in the art; for example, urea such as dimethyl urea, 1,1-dimethyl-3-phenylurea, toluyl-bis-1,1-dimethylurea, 3-(3-trifluoromethylphenyl)-1,1-dimethylurea, 2-phenylimidazole and / or benzyldimethylamine can be used as an accelerator.

[0037] Powder coating can also be used particularly advantageously for individual rod insulation using hairpin, wave winding, and / or plug-in coil technology. Individual rods can be coated or sprayed with powder coating, e.g., in an automated process, using an assembly line, and then subjected to thermal and / or UV curing.

[0038] As a wet paint, the formulation is dissolved in a solvent. Suitable solvents include: acetone, isopropanol, ethyl ester, methyl ethyl ketone, butyl acetate, in any mixture and / or combination. A common thixotropic agent may also be added to the wet paint.

[0039] According to a further advantageous embodiment, the PFTs of component B are present in particle sizes ranging from 1 μm to 3 mm, preferably from 0 μm to 1000 μm. The PFTs in component B can be identical or different in terms of their particle size and shape. In particular, different thermosets and / or thermoplastics and / or different particle sizes of a plastic can be present in a mixture.

[0040] The incorporation of at least one particle fraction with an average grain size d50 in the range from 500 nm to 300 pm, in particular from 1 pm to 200 pm and for example in the range from 2 to 100 pm, for example between 2.5 pm and 10 pm, has proven particularly advantageous.

[0041] For example, component B contains a multimodal mixture of particles of various grain sizes, so that coarser and finer fractions complement each other, particularly with regard to the mechanical properties during processing of the formulation. It is known that smaller particle fractions can act like ball bearings for coarser particles with regard to the flowability of the formulation.

[0042] The PFTs of component B can be present in the formulation, as required, in amorphous, semi-crystalline, with crystalline portions, or in any mixture of the aforementioned modifications. Some or all of the PFTs of component B can also be reinforced, particularly fiber-reinforced. All types of non-electrically conductive fillers can be incorporated; for example, aramid fiber-reinforced or glass fiber-reinforced thermoplastic particles can be included in component B.

[0043] The PFTs include, for example, polymeric solid filler particles made of materials such as high-performance plastics - preferably with a relative temperature index greater than 190°C and preferably greater than 200°C - such as

[0044] Thermoplastic polyimides - TPI-, see also structural formulas I to III, polyetherimide - PEI-, polybenzimidazole -PBI-, thermoplastic silicone, in the form of solid polymeric filler particles after appropriate frost treatment, polyamideimide -PAI-, polyether ketones such as

[0045] Polyetheretherketone -PEEK-, polyetherketoneketone -PEKK-, polyetherketoneetherketoneketone -PEKEKK- polyetherketone -PEK-, polymeric sulfur compounds, such as polysulfone -PSU-, polyphenylene sulfide -PPS-, polyethersulfone -PES-, polyphenylenesulfone -PPSU-, each alone or in any mixtures, blends and / or copolymers present in the particle.

[0046] For example, component B comprises PFTs made of a thermoplastic polyimide - TPI-, which corresponds to the structural formula I: Structural formula I and / or structural formula II

[0047] Structural formula II with

[0048] - applies to both structural formulas I and II - n = 1 to 10 000

[0049] R is the same or different and represents any aliphatic and / or aromatic organic, hydrocarbon-based, optionally heteroatom-substituted, organic radicals with any functional groups.

[0050] Therefore, R can be alkyl, aryl, O,S-alkyl, O,S-aryl, N,P-aryl, N,P-alkyl with any functional groups, such as acid groups, ester groups, ether groups, etc.

[0051] According to another embodiment, component B comprises, for example, PFTs from a TPI comprising the structural formula III - at least as a component:

[0052] Structural formula III

[0053] Again with n in the range 1 to 10 000 .

[0054] A thermoplastic compound comprising an element with structure III can also be present as a component of any copolymers and / or blends as PET in component B.

[0055] Particles made of thermoplastic high-performance plastics with the above-mentioned structural formulas I to III can, for example, have glass transition temperatures Tgs of up to 350 ° C.

[0056] Thermoplastic high-performance plastics used as PET, for example, can be present in pure form but also in any blends and / or copolymers in PFTs of component B.

[0057] Component B includes, for example, various particle fractions, each containing different high-performance plastics.

[0058] PFTs of component B may be coated or uncoated.

[0059] PFTs of component B, for example, are surface-treated, whereby chemical and / or physical functionalization of the surface with a view to better bonding to the thermosetting resin represents one possible surface treatment.

[0060] Component B preferably comprises at least one particle fraction of PFTs that has fiber-reinforced particles. In addition to component B, the formulation may contain additional fillers such as quartz powder, fused silica, mica, or siloxane, alone or in any desired mixtures.

[0061] In addition, the formulation may also contain the usual additives for potting, powder coating or wet coating, such as flow aids, degassers and any other additives for electrical insulation systems that are notoriously well known in the art.

[0062] The invention is explained in more detail below using some examples.

[0063] Example 1 :

[0064] Base resin Bisphenol A: 46.5%

[0065] Hardener Dicyandiamide: 0.5%

[0066] Accelerator: Toluyl-bis-1,1-dimethylurea: 0.5%

[0067] Filler: Quartz flour: 20%

[0068] Filler 2: Siloxane-polyimide copolymer 10%

[0069] High temperature index polymer filler "PFT": Polyimide, structural formula II 20% Additive: Flow control agent 1%

[0070] Additive: Degasser 1.5

[0071] Example 2 :

[0072] Base resin Bisphenol A: 55.5%

[0073] Hardener Dicyandiamide: 1%

[0074] Accelerator: Toluyl-bis-1,1-dimethylurea: 1% PET: Polyimide, structural formula II 40%

[0075] Additive: Anti-crater and leveling agent 1.5%

[0076] Additive: Degasser 1%

[0077] By adding the PFTs in component B, an increase in the temperature index from 154 °C of the pure DGEBA / DICY formulation to 183 °C of the formulation containing 30% component B in the form of PFTs based on thermoplastic polyimide was measured.

[0078] The presently disclosed invention provides an insulation formulation for insulation systems as well as insulating coatings which shows a drastic improvement over the prior art, in particular the base resins without PFTs, because it simultaneously provides a

[0079] - excellent resistance to environmental influences,

[0080] - sufficient - 3 months or longer - storage stability at room temperature,

[0081] - Improved thermomechanical behavior of the insulation systems and insulating coatings produced from them and

[0082] - shows good processability as casting, powder coating or wet coating.

[0083] The invention relates generally to the field of insulation, in particular to a formulation for high-temperature insulation at operating temperatures of 200°C and more. The insulation serves as insulation for electrical conductors. Thus, the invention relates to an insulation system for an electrical machine, in particular a rotating electrical machine with a stator, such as an electric motor and / or a generator with improved temperature resistance of the polymeric insulation system components and / or an insulating coating for generatively manufactured conductors or parts thereof, busbars, connecting rails and / or terminal boxes.

[0084] The present invention discloses for the first time a formulation for a powder coating, for a powder for a fluidized bed, for a casting resin and / or a formulation for a wet coating which comprises PFTs, i.e. high-performance plastics in fully cured, polymeric and - even in the case of thermoplastics - solid form, as component B. It has been shown that PFTs can considerably increase the thermal resistance of the resulting material and at the same time bring even improved thermomechanical properties to an insulation system and / or an insulating coating produced therefrom. The invention is used for the production of insulation systems for electrical rotating machines. Further fields of application of the formulation according to the invention are, for example, insulating coatings of generatively manufactured conductors, busbars and / or connecting rails and the coating of terminal boxes.

Claims

Patent claims 1. Formulation for an insulation system and / or an insulating coating, in the form of a casting, powder coating and / or solvent-containing wet coating, comprising at least one component B, wherein component A, an uncrosslinked, liquid or solid base resin with the hardener and / or accelerator required for curing, is also preferably included, and component B is in the form of a PFT, i.e. in the form of a polymeric filler which is solid at room temperature under normal conditions and has a high relative temperature index, in particular greater than 160°C, wherein component A is present in the range from 0% to 99% by mass and component B is present in the range from 1% to 100% by mass, based on 100% of the solvent-free formulation.

2. Formulation according to claim 1, wherein the base resin comprises one or more compounds selected from the group consisting of epoxy resin, polyurethane resin, polyisocyanate resin, polyimide resin, polyesterimide resin and / or polyester resin, alone or in any desired mixtures, blends and / or copolymers.

3. Formulation according to one of claims 1 or 2, wherein the hardener comprises a compound which is based on anhydride, imidazole and / or dicyanamide, as well as any derivatives and / or mixtures of these compounds. 4 . Formulation according to one of the preceding claims, wherein component A comprises an accelerator.

5. Formulation according to one of the preceding claims, which comprises further fillers such as fused silica, quartz powder and / or siloxane, alone or in any mixtures and combinations.

6. Formulation according to one of the preceding claims, which is present as a wet paint in a solvent such as acetone, isopropanol, ethyl ester, methyl ethyl ketone, butyl acetate in any mixtures and / or combinations.

7. Formulation according to one of the preceding claims, which comprises in component B PFTs with grain sizes of 1m to 3 mm.

8. Formulation according to one of the preceding claims, which comprises in component B PFTs with grain sizes of 0.1pm to 1000pm.

9. Formulation according to one of the preceding claims, which comprises in component B at least two different particle fractions of PFTs with grain sizes of 1m to 3 mm.

10. Formulation according to one of the preceding claims, wherein component B comprises PFTs made of high-performance plastic such as thermoplastic polyimides - TPI-, see also structural formulas I to III, Polyetherimide - PEI-, polybenzimidazole -PBI-, polysiloxane, polyamideimide -PAI-, polyether ketones such as polyether ether ketone -PEEK-, polyether ketone ketone -PEKK-, polyether ketone ether ketone ketone -PEKEKK- polyether ketone -PEK-, polymeric sulfur compounds such as polysulfone -PSU-, polyphenylene sulfide -PPS-, polyether sulfone -PES-, polyphenylene sulfone -PPSU-. each present alone or in any mixtures, blends and / or copolymers in the particle.

11. Formulation according to one of the preceding claims, wherein component B comprises various PFT particle fractions, each containing different high-performance plastics.

12. Formulation according to one of the preceding claims, wherein component B comprises several different particle fractions with PFTs of different degrees of crystallinity, i.e. amorphous, semi-crystalline and / or crystalline PFTs.

13. Formulation according to one of the preceding claims, wherein component B comprises at least one fiber-reinforced PFT particle fraction.

14. Shaped body obtainable by curing a formulation according to one of claims 1 to 13, wherein the shaped body forms an insulation system or parts of an insulation system and / or an electrically insulating coating or parts of an electrically insulating coating.

15. Use of a formulation according to any one of claims 1 to 13 for producing an insulation system and / or an insulating coating by casting, powder coating, fluidized bed coating, wet painting and / or conductor insulation.

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