Formulations for insulation systems, use thereof and molded bodies

Abstract

The present invention relates generally to the field of insulation, in particular to formulations for high temperature insulation at operating temperatures of 200 DEG C and higher. The insulation is used for insulation of the electrical conductor. The invention therefore relates to an insulation system for an electric machine, in particular a rotary electric machine with a stator, such as an electric motor and / or a generator, having an improved temperature resistance of the polymer composition of the insulation system, and / or an insulation coating for additively manufactured conductors or parts thereof, bus bars, connecting bars and / or terminal boxes. Pouring materials, powder coatings and / or formulations for wet coatings are disclosed for the first time, comprising high performance thermoplastics as fillers, in which these fillers have been shown to significantly increase heat resistance and provide better thermomechanical properties in insulation systems made therefrom.

Description

[0001] The present invention relates generally to the field of insulation and in particular to a formulation for high-temperature insulation at maximum operating temperatures of up to 200° C. and higher. The formulation, in the form of a molded body obtainable therefrom by curing, serves as an insulation system, as an insulating coating for an electrical conductor and / or as a part thereof, respectively. For example, the present invention also relates to a molded body which is at least a part of an insulation system of an electrical machine, in particular a rotating electrical machine with a stator, such as an electric motor and / or a generator, which has an improved temperature resistance of the polymer component of the insulation system. Similarly, the present invention relates to a molded body which is part of an insulating coating or forms the entire insulating coating, in particular an insulating coating for an electrical conductor, an insulating coating for a busbar, an insulating coating for a connecting strip and / or an insulating coating for a terminal box, for example produced by additive manufacturing.

[0002] The electric machines of drive systems are usually equipped with stators, such as in the case of electric motors and generators in the medium and high voltage range, and contain electrical conductors, primary insulation, conductor insulation, such as wire insulation with sub-conductor insulation, and a stator laminated core. The purpose of the primary insulation is to electrically insulate the phases from each other, from the grounded stator laminated core and from the environment.

[0003] Conductor insulation insulates the conductors of the coils from each other. Electric motors are usually operated at the highest possible current density. Traction motors operate at high temperatures, for example up to 220°C for heat-resistant grades of polymer-based plastics. The polymer plastics suitable for this purpose are therefore limited to a few polymer types.

[0004] On the other hand, wound insulation systems contain not only surface insulation material and / or insulating tapes, but also impregnation resins. Due to various requirements, surface insulation materials - which form, for example, slot liners and / or insulating tapes - have been based to date on meta-aramids and / or polyimides in addition to mica and glass. Due to the high heat resistance class resulting from the low processing temperature, thermosetting materials with polyesterimides and / or silicones are often used as impregnation resins in traction motors. In industrial high-voltage motors, epoxies are often used.

[0005] In the case of insulation systems with mica tapes, the paper is bonded to a glass fabric carrier and / or a PET and / or PI film and cut into narrow rolls, which are subsequently formed into insulation tapes and wound around conductors or coils, for example.

[0006] In the case of extruded conductor insulation and / or in the case of spun tape conductor insulation - less frequently in the case of solvent-containing wire enamels - it is customary to use PEEK, PI, PAI, PPS, PEI, polyesterimides (thermosetting materials) and similar synthetic resins. In particular, thermosetting wire enamels optimized with regard to partial discharge resistance are commercially available for conductor insulation.

[0007] "Hairpin technology" is a winding technology for stators in electric motors and generators, which is a subcategory of wave winding. It is used in particular for traction motors in electric vehicles. In contrast to form-wound winding technology, wave winding technology is based on windings of wires that are inserted individually into the stator slots of a laminated core, not in combination as coils. These inserted coils, so-called hairpins, wavy hairpins ("continuous hairpins") and / or I-pins, are enameled and / or extruded flat copper wires that are bent into wavy, U-shaped or I-shaped bends.

[0008] The I-pin is a flat copper wire that is shaped into a straight line, for example, and in the case of the "continuous hairpin" wave winding concept, a so-called winding mat is produced and then inserted into the laminated core from the inside. Compared to the U-pin and I-pin technology, this has a significantly lower complexity in the connection method of the individual pins.

[0009] The construction of a hairpin stator differs from a conventional stator only in the nature of the winding system - the other components of the stator remain essentially unchanged. The winding in the form of an insulated winding wire is achieved by means of inserted coils in the hairpin stator.

[0010] New and more cost-effective methods are being tested in hairpin technology, which represents advanced technology for stators in electric machines. For example, flat copper wires with typical hairpin geometry are introduced into the slots of a laminated core in a forming-based assembly method. However, the soldered or welded connection points of the individual hairpins must be insulated from one another with a coating, since they are not protected by the conductor insulation. However, the heat resistance of the lacquers currently used is limited to thermal class 180 (H).

[0011] Here, it is provided that the windings, wires and / or hairpins are preferably additionally fixed in the slots by casting, dipping, dripping, impregnation and / or injection molding with synthetic resin to produce the finished insulation system. Alternatively, the sub-conductors insulated by wire extrusion can be fixed in the slots by injection molding.

[0012] There is still a need for improved technology for the production of insulation systems and / or insulation coatings, which are particularly also suitable for the above-mentioned applications - including for plug-in coil technology and / or wave winding technology - such as can be used, for example, in traction motors of rail vehicles, passenger vehicles, heavy-duty vehicles, and / or for insulation coatings of conductors and / or coils for additive manufacturing, for example, as well as busbars or connecting strips.

[0013] The object of the present invention is therefore to provide formulations for insulating coatings and / or insulation systems for rotating electrical machines, in particular for use at maximum operating temperatures above 170° C., in particular above 200° C., preferably even up to above 220° C., which also applies to plug-in coil and / or wave winding technology.

[0014] This object is achieved by the subject matter of the invention as disclosed in the claims, the description and the examples.

[0015] The subject matter of the present invention is therefore a preparation for an insulation system and / or an insulation coating in the form of a casting material, a powder coating and / or a solvent-containing wet coating, which comprises at least a component B, wherein

[0016] It also preferably comprises component A, ie a liquid or solid base resin in uncrosslinked form, which contains the curing agent and / or accelerator required for curing,

[0017] and

[0018] Component B is in the form of a PFT, ie in the form of a polymer filler which is solid under standard conditions at room temperature and has a high relative temperature index, in particular above 160° C., wherein

[0019] Based on 100% of the solvent-free preparation, component A is present in an amount of 0 to 99% by mass, and component B is present in an amount of 1 to 100% by mass.

[0020] The invention further provides a shaped body obtainable by curing the above-described preparation, wherein the shaped body forms an insulation system or part of an insulation system and / or an electrically insulating coating or part of an electrically insulating coating.

[0021] Finally, the invention provides for the use of a formulation as described above for producing insulation systems, insulation coatings and / or conductor insulation by powder coating, fluidized bed coating, wet coating and / or casting.

[0022] “Relative temperature index” in this context refers to the relative temperature index “TI” according to IEC 60216 or DIN EN 60216. This corresponds to the temperature value in ° C. derived from the thermal resistance long-term relationship at 5% mass loss for 20,000 hours.

[0023] The formulation according to the invention forms an insulation system in the form of a conductor insulation material and / or a portion of a conductor insulation material after curing. The formulation can be processed, for example, but not limited to, by powder coating, pouring coating, fluidized bed coating and / or wet coating of the conductor, the portion of the conductor and / or the associated housing. The molded body is preferably cured thermally and / or by radiation, in particular UV curing.

[0024] The molded body formed from the formulation can then, for example, partially or completely form one or more individual strips of insulation, the insulation of a winding head and / or the insulation of a switching zone of a winding head and / or even the insulation of an entire wire winding. Furthermore, it can serve as a subconductor insulation and / or as an individual strip of insulation for other conductor elements in plug-in coils, wave winding technology, and / or as an insulating coating for generatively manufactured, in particular additively manufactured, conductor elements.

[0025] Finally, the formulation can completely or partially form the insulating coating of busbars and / or connection bars and / or terminal boxes.

[0026] Conductor insulation is the electrical insulation of, for example, individual conductor windings of a coil from one another and / or from the conductors of a line winding and / or from the environment and / or from ground, for example an electric machine.

[0027] Fluidized bed coating is understood to mean coating the conductor in a fluidized bed filled with a powder coating formulation. In particular, powders made from compounds that are solid under standard conditions are used here, i.e. in addition to the particle-shaped thermoplastics that are in solid form anyway, the base resin is preferably also in solid form here.

[0028] Powder coating, in particular electrostatic powder coating, is carried out, for example, by spraying and / or a fluidized bed process. Powders made of solids are used here, ie, in addition to the particle-shaped thermoplastics which are in any case in solid form, the base resin is also present as a solid.

[0029] Wet coating is carried out, for example, by painting, brushing, dipping, spraying, spin coating and / or dip coating. The formulation dissolved in a solvent is applied to the conductor, the solvent is then at least partially removed, and the formulation is cured. In addition, the base resin can be present as a solid and / or as a liquid.

[0030] Casting is carried out with solvent-free liquid formulations, in which, in contrast to formulations used as powder coatings, the base resin is present as a liquid under standard conditions.

[0031] "Standard conditions" - particularly with regard to processing conditions and storage stability - mean room temperature of 25°C, ambient air and standard pressure.

[0032] The general finding of the present invention is that the addition of plastic filler particles which are present in solid and polymer form and have a high relative temperature index - polymer fillers with a high relative temperature index or "PFT" - in formulations for casting materials, fluidized bed powder forms, powder coating forms and / or wet coatings for the production of electrical insulation systems and / or insulating coatings has advantages with regard to thermomechanical stability and in particular with regard to temperature stability.

[0033] This is particularly advantageous in the case of an increase in the power density of the electrical conductor, since an increase in the power density is always accompanied by an increase in the operating temperature.

[0034] The PFT according to the invention has a high temperature index "TI", which is in particular above 160° C., preferably above 170° C., particularly preferably above 180° C., most preferably above 190° C. The PFT used is preferably those with a high glass transition temperature. This is in particular the case for thermoplastic, elastomeric and / or thermosetting particles having a glass transition temperature of greater than or equal to 130° C., preferably greater than or equal to 150° C., preferably mixed with component A (comprising the base resin in still uncrosslinked form, curing agent and / or accelerator), wherein the presence of the PFT achieves significant mechanical and / or thermomechanical advantages and / or a significant increase in the temperature resistance of the resulting insulation system and / or insulation coating.

[0035] The thermoplastic, elastomeric and / or thermosetting PFT of component B are identical or different, for example with regard to material, surface treatment, surface coating, crystallinity, amorphism, particle size, particle shape and / or fiber reinforcement. The PFT is preferably in deagglomerated form.

[0036] Component B contains PFT and its mass in the dry preparation is 1 to 99 mass%, particularly 10 to 60 mass%, very particularly preferably 20 to 50 mass%, particularly preferably 20 to 30 mass%, based on 100 mass% of the solvent-free preparation.

[0037] The "base resin" including optional curing agents, accelerators, additives, auxiliary substances, additional fillers then forms the remainder up to 100% by mass of the solvent-free formulation.

[0038] The term "base resin" in the sense of "main component of the preparation" is no longer suitable for the present invention, since in certain cases where component B represents more than 50% by mass of the preparation, this resin serves only as a binder or, for example in the case of powder coating preparations, is no longer used at all.

[0039] According to an advantageous embodiment of the invention, present as component A in the formulation is a base resin in the form of a thermosetting resin which has not yet been crosslinked and which comprises one or more compounds selected from epoxy resins, polyurethane resins, polyisocyanate resins, polyimide resins, polyesterimide resins and / or polyester resins as any desired mixtures, blends and / or copolymers. For example, the uncrosslinked thermosetting synthetic resin in the formulation comprises compounds such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, novolac resins, aliphatic epoxy resins and / or aromatic epoxy resins. In the case of solvent-free use as a casting material and / or as a solvent-containing wet coating, the base resin can also be in liquid form under standard conditions, and in the case of use as a powder coating, it is a powder, i.e. a solid.

[0040] Furthermore, a curing agent such as an anhydride-based compound, an imidazole-based compound, a bisphenol-based compound and / or a dicyandiamide-based compound is contained in component A accordingly, ie in a stoichiometrically suitable amount and in a suitable chemistry relative to the base resin.

[0041] In order to initiate curing after the formulation is applied (for example, after the powder coating is sprayed) to the body to be insulated (for example, an inserted coil in the case of hairpin technology), a small amount of accelerator, for example 0.3% to 2% by mass, may also be contained in component A. Accelerators for this application are known to those skilled in the art; examples of useful accelerators include ureas such as dimethyl urea, 1,1-dimethyl-3-phenyl urea, toluene bis-1,1-dimethyl urea, 3-(3-trifluoromethylphenyl)-1,1-dimethyl urea, 2-phenylimidazole and / or benzyldimethylamine.

[0042] Powder coatings can also be used particularly advantageously for the insulation of individual strips in hairpin technology, wave winding technology and / or plug-in coil technology. Here, the individual strips can be coated or sprayed with powder coating, for example automatically, for example in a conveyor belt method, and then thermally and / or UV-cured.

[0043] As a wet coating, the preparation is in the form of a solution in a solvent. Examples of suitable solvents are: acetone, isopropanol, ethyl acetate, methyl ethyl ketone, butyl acetate in any desired mixture and / or combination. In addition, the wet coating may also be admixed with conventional thixotropic agents.

[0044] According to another advantageous embodiment, the PFT of component B has a particle size of 1 nm to 3 mm, preferably 0.1 μm to 1000 μm. The PFT in component B can be identical or different in terms of their particle size and particle shape. In particular, different thermosetting materials and / or thermoplastics and / or plastics of different particle sizes can also be present as a mixture.

[0045] It has been found to be particularly advantageous to incorporate at least one average particle size d50 A particle fraction of 500 nm to 300 μm, in particular 1 μm to 200 μm, for example 2 to 100 μm, for example 2.5 μm to 10 μm.

[0046] For example, a multimodal mixture of particles of different particle sizes is present in component B so that the coarser and finer fractions complement each other, especially in terms of mechanical properties when the formulation is processed. For example, it is known that smaller particle fractions can act as ball bearings for larger particles in terms of flowability of the formulation.

[0047] The PFT of component B can be present in the formulation - as desired - in amorphous form, in partially crystalline form, in a form containing crystalline parts and in any desired mixtures of the above variants. Some or all of the PFT of component B can also be present in reinforced form, in particular fiber-reinforced form. All types of non-conductive fillers can be incorporated, so that component B can contain, for example, aramid fiber-reinforced, glass fiber-reinforced thermoplastic particles.

[0048] The PFT comprises solid polymer filler particles, for example made of a material such as a high performance plastic, preferably having a relative temperature index of greater than 190° C., preferably greater than 200° C.

[0049] Thermoplastic polyimide (TPI), see also formulas I to III,

[0050] Polyetherimide (PEI),

[0051] Polybenzimidazole (PBI),

[0052] Thermoplastic silicones in the form of polymer filler particles which are in solid form after suitable frost treatment,

[0053] Polyamide-imide (PAI),

[0054] Polyetherketones, e.g.

[0055] Polyetheretherketone (PEEK),

[0056] Polyetherketoneketone (PEKK),

[0057] Polyetherketoneetherketoneketone (PEKEKK),

[0058] Polyetherketone (PEK),

[0059] Polymeric sulphur compounds, e.g.

[0060] Polysulfone (PSU),

[0061] Polyphenylene sulfide (PPS),

[0062] Polyethersulfone (PES),

[0063] Polyphenylsulfone (PPSU),

[0064] Each is present in the particles individually or in any desired mixtures, blends and / or copolymers.

[0065] For example, component B comprises a PFT made from a thermoplastic polyimide (TPI) corresponding to formula I and / or formula II:

[0066] Structural Formula I

[0067]

[0068] Structural formula II

[0069]

[0070] in

[0071] -Applicable to both structural formula I and II-

[0072] n = 1 to 10,000

[0073] R are identical or different and are any desired aliphatic and / or aromatic organic, hydrocarbon-based, optionally heteroatom-substituted organic radicals having any desired functional groups.

[0074] Thus, it is possible that R = alkyl, aryl, O,S-alkyl, O,S-aryl, N,P-aryl, N,P-alkyl with any desired functional group such as acid, ester, ether, etc.

[0075] According to another embodiment, component B comprises PFT, for example made from TPI, which - at least as a component - comprises the structural formula III:

[0076] Structural formula III

[0077]

[0078] Likewise, n is 1 to 10,000.

[0079] However, thermoplastic compounds comprising elements of structure III can also be present in component B as a constituent of any desired copolymers and / or blends as PFT.

[0080] Particles made of thermoplastic high-performance plastics of the abovementioned formulae I to III can have a glass transition temperature Tg of, for example, up to 350° C.

[0081] For example, the thermoplastic high-performance plastics used as PFT can be in pure form, but can also be present in the PFT of component B as any desired blends and / or copolymers.

[0082] Component B comprises, for example, different particle fractions, each of which contains a different high-performance plastic.

[0083] The PFT of component B is in some cases in coated or uncoated form.

[0084] The PFT of component B is, for example, in surface-treated form, wherein one possible way for the surface treatment is chemical and / or physical functionalization of the surface with a view to achieving better bonding with the thermosetting resin.

[0085] Preferably, component B comprises at least one PFT particle fraction having fiber-reinforced particles. In addition to component B, the formulation may also contain further fillers, such as quartz powder, fused quartz, mica, siloxanes, either alone or in any desired mixtures.

[0086] Furthermore, the formulations may additionally contain customary additives for casting materials, powder coatings or wet coatings, such as leveling agents, degassing agents and any other desired known additives for electrical insulation systems.

[0087] The present invention is explained in more detail below with reference to several examples.

[0088] Embodiment 1:

[0089] Base resin, bisphenol A: 46.5%

[0090] Curing agent, dicyandiamide: 0.5%

[0091] Accelerator, toluene bis-1,1-dimethylurea: 0.5%

[0092] Filler, quartz powder: 20%

[0093] Filler 2, siloxane / polyimide copolymer: 10%

[0094] Polymer filler with high temperature index (PFT), polyimide, structure II: 20% Additive, leveling agent: 1%

[0095] Additive, degassing agent: 1.5%

[0096] Embodiment 2:

[0097] Base resin, bisphenol A: 55.5%

[0098] Curing agent, dicyandiamide: 1%

[0099] Accelerator, toluene bis-1,1-dimethylurea: 1%

[0100] PFT, polyimide, structural formula II: 40%

[0101] Additives, anti-crater and leveling agent: 1.5%

[0102] Additive, degassing agent: 1%

[0103] By adding PFT to component B, an increase in the temperature index from 154° C. for the pure DGEBA / DICY formulation to 183° C. for the formulation with 30% of component B in the form of PFT based on thermoplastic polyimide can be measured.

[0104] By the invention disclosed herein, there are provided insulation formulations for insulation systems and insulation coatings which exhibit significant improvements over the prior art, particularly base resins which do not contain PFT, because they exhibit both:

[0105] -Excellent resistance to environmental influences,

[0106] - Excellent storage stability at room temperature - 3 months or longer,

[0107] - improved thermomechanical behavior of insulation systems and insulation coatings made therefrom, and

[0108] -Good processability as casting material, powder coating or wet coating.

[0109] The present invention relates generally to the field of insulation, and in particular to formulations for high temperature insulation at operating temperatures of 200° C. and above. The insulation serves as insulation for electrical conductors. For example, the present invention relates to insulation systems for electrical machines, in particular rotating electrical machines with stators, such as motors and / or generators, with improved temperature resistance of the polymer components of the insulation system, and / or to insulating coatings for producing manufactured conductors or parts thereof, busbars, connecting bars and / or terminal boxes.

[0110] The invention discloses for the first time formulations for powder coatings, for fluidized bed powders, for casting resins and / or for wet coatings, which contain PFT, i.e. a high-performance plastic in fully cured, polymerized and - even in the case of thermoplastics - solid form, as component B, wherein it has been found that the PFT can significantly increase the heat resistance of the resulting material while also introducing improved thermomechanical properties in insulation systems made therefrom and / or insulation coatings made therefrom. The invention is used for the production of insulation systems for rotating electrical machines. Other fields of application of the formulations according to the invention are, for example, the production of insulation coatings for manufactured conductors, busbars and / or connecting bars and the coating of terminal boxes.

Claims

1. A preparation for an insulation system and / or an insulation coating in the form of a casting material, a powder coating and / or a solvent-containing wet coating, comprising at least component B, wherein It also preferably comprises component A, ie a liquid or solid base resin in uncrosslinked form, which contains the curing agent and / or accelerator required for curing, and Component B is in the form of a PFT, ie in the form of a polymer filler which is solid under standard conditions at room temperature and has a high relative temperature index, in particular above 160° C., wherein Based on 100% of the solvent-free preparation, component A is present in an amount of 0 to 99% by mass, and component B is present in an amount of 1 to 100% by mass.

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

3. The formulation according to any one of claims 1 or 2, wherein the curing agent comprises a compound which is an anhydride-based compound, an imidazole-based compound and / or a dicyandiamide-based compound, and any desired derivatives and / or mixtures of these compounds.

4. A formulation according to any one of the preceding claims, wherein component A comprises an accelerator.

5. Formulation according to any of the preceding claims, comprising further fillers, such as fused quartz, quartz powder and / or silicones, alone or in any desired mixtures and combinations.

6. The formulation according to any of the preceding claims in the form of a wet coating in a solvent such as acetone, isopropanol, ethyl acetate, methyl ethyl ketone, butyl acetate in any desired mixtures and / or combinations.

7. A formulation according to any one of the preceding claims, comprising in component B a PFT having a particle size of from 1 nm to 3 mm.

8. A formulation according to any one of the preceding claims, comprising in component B PFT having a particle size of 0.1 μm to 1000 μm.

9. The preparation according to any of the preceding claims, comprising in component B at least two different PFT particle fractions having a particle size of 1 nm to 3 mm.

10. A formulation according to any one of the preceding claims, wherein component B comprises a PFT made of a high-performance plastic, such as Thermoplastic polyimide (TPI), see also formulas I to III, Polyetherimide (PEI), Polybenzimidazole (PBI), Polysiloxane, Polyamide-imide (PAI), Polyetherketone, e.g. Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherketoneetherketoneketone (PEKEKK), Polyetherketone (PEK), Polymeric sulphur compounds, e.g. Polysulfone (PSU), Polyphenylene sulfide (PPS), Polyethersulfone (PES), Polyphenylsulfone (PPSU), Each is present in the particles individually or in any desired mixtures, blends and / or copolymers.

11. The formulation according to any of the preceding claims, wherein component B comprises different PFT particle fractions, each containing a different high-performance plastic.

12. The formulation according to any one of the preceding claims, wherein the component B comprises a plurality of different particle fractions having PFT of different crystallinity, ie PFT in amorphous form, partially crystalline form and / or crystalline form.

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

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

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

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