Solid Insulation Material

Abstract

Various embodiments may include a solid insulation material, e.g. in tape form, the use thereof in a vacuum impregnation process, and/or an insulation system produced therewith and also an electrical machine having the insulation system, for the medium- and high-voltage sector. Some examples include rotating electrical machines in the medium- and high-voltage sector and also semifinished products for electrical switchgear. The solid insulation material and the insulation system produced therewith are characterized in that it can be produced in an anhydride-free manner, wherein the curing catalyst is, for example, an adduct of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups.

Claims

1. A solid insulation material for use with an anhydride-free impregnating agent for the preparation of an insulation system in a vacuum impregnation process, the solid insulation material comprising: a carrier; a barrier material; a curing catalyst; and a tape adhesive; wherein the curing catalyst and the tape adhesive are inert to one another; at a pressure and a temperature associated with the vacuum impregnation process, the curing catalyst and the tape adhesive react with an anhydride-free impregnating agent with gelling times of 1 to 15 hours; and the curing catalyst is obtained by reaction of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups.

2. The insulation material as claimed in claim 1, wherein the compound containing oxirane groups has 1 to 4 oxirane functionalities per molecule.

3. The insulation material as claimed in claim 1, wherein the compound containing oxirane groups comprises a glycidyl compound.

4. The insulation material as claimed in claim 1, wherein the compound containing oxirane groups is liquid at room temperature.

5. The insulation material as claimed in claim 1, wherein the curing catalyst comprises an adduct of one or more 1H-acid dinitrogen heterocycles and/or 1H-acid trinitrogen heterocycles with a compound containing oxirane groups.

6. The insulation material as claimed in claim 1, wherein the compound containing oxirane groups is a compound selected from the following group of compounds: monoglycidyl ether and/or ester compound (n=1), diglycidyl ether and/or ester compound (n=2), triglycidyl ether and/or ester compound (n=3), tetraglycidyl ether and/or ester compound (n=4), and mixtures thereof.

7. The insulation material as claimed in claim 1, wherein the curing catalyst has a nitrogen density D in a range from 1 to 15 mmol/g.

8. The insulation material as claimed in claim 1, wherein the curing catalyst comprises a compound containing oxirane groups and an adduct of at least one of the following: 1H-2-methylimidazole (CAS no. 693-98-1), 1H-2-ethylimidazole (CAS no. 1072-62-4), 1H-4-ethyl-2-phenylimidazole, 1H-3,5-dimethylpyrazole, 1H-imidazole (CAS no. 288-32-4), 1H-4(5)-methylimidazole (CAS no. 822-36-6), 1H-2-ethyl-4-methylimidazole (CAS no. 931-36-2), 1H-4-methyl-2-phenylimidazole (CAS no. 827-43-0), 1H-4-phenylimidazole (CAS no. 670-95-1), 1H-5-methyl-2-phenylimidazole-4-methanol (CAS no. 13682-32-1), 1H-pyrazole (CAS no. 288-13-1), 1H-3-phenylpyrazole (CAS no. 2458-26-6), 1H-5-methylpyrazole, 1H-3,4-dimethylpyrazole (CAS no. 2820-37-3), 1H-3,5-dimethylpyrazole (CAS no. 67-51-6), 1H-3-tert-butylpyrazole (CAS no. 15802-80-9), and/or 1H-4-ethylpyrazole (CAS no. 17072-38-7).

9. The insulation material as claimed in claim 1, wherein the curing catalyst comprises 1-4 covalently bonded hydroxyl groups per molecule.

10. The insulation material as claimed in claim 1, wherein the tape adhesive comprises an addition product of a bisphenol, diol, triol, and/or higher alcohol (A(OH).sub.n), with a cyclohexene oxide and/or a cyclohexene oxide derivative (Cy), wherein A(OH).sub.n comprises at least one compound selected from the following group of compounds: monoethylene glycol (C.sub.2H.sub.4)(OH).sub.2, butanediols (C.sub.4H.sub.8)(OH).sub.2, butenediols (C.sub.4H.sub.6)(OH).sub.2, butynediol (C.sub.4H.sub.4)(OH).sub.2, polyethylene glycols H(OC.sub.2H.sub.4).sub.x(OH).sub.2 with x=1 to 5000, propylene glycol (C.sub.3H.sub.6)(OH).sub.2, polypropylene glycols H(OC.sub.3H.sub.6).sub.x(OH).sub.2 with x=1 to 5000, diethylene glycol (C.sub.2H.sub.8O)(OH).sub.2, propanediols (C.sub.3H.sub.6)(OH).sub.2, neopentyl glycol (C.sub.5H.sub.10)(OH).sub.2, cyclopentanediols (C.sub.5H.sub.8)(OH).sub.2, cyclopentenediols (C.sub.5H.sub.6)(OH).sub.2, glycerol (C.sub.3H.sub.5)(OH).sub.3, pentanediols (C.sub.5H.sub.10)(OH).sub.2, pentaerythritol (C.sub.5H.sub.8(OH).sub.4, hexanediols (C.sub.6H.sub.12)(OH).sub.2, hexylene glycols (C.sub.6H.sub.12)(OH).sub.2, heptanediols (C.sub.7H.sub.14)(OH).sub.2, octanediols (C.sub.8H.sub.16)(OH).sub.2, polycaprolactone diols, polycaprolactone triols, hydroquinone (C.sub.6H.sub.4)(OH).sub.2, resorcinol (C.sub.6H.sub.4)(.sub.OH).sub.2, (pyro)catechol (C.sub.6H.sub.4)(OH).sub.2, rucinol (C.sub.10H.sub.12)(OH).sub.2, triethylene glycol (C.sub.6H.sub.12)(OH).sub.2 fully aromatic, partially hydrogenated and/or fully hydrogenated bisphenol A (C.sub.15H.sub.14)(OH).sub.2, (C.sub.15H.sub.28)(OH).sub.2, bisphenol F (C.sub.13H.sub.10)(OH).sub.2, bisphenol S (C.sub.12H.sub.8O.sub.2S)(OH).sub.2 tricyclodecane dimethanol (C.sub.12H.sub.18)(OH).sub.2, and glycerol carbonate (C.sub.4H.sub.5)(OH).sub.1.

11. The insulation material as claimed in claim 1, wherein the tape adhesive comprises a compound selected from the following group of compounds: tricyclomethane dimethanol (CAS no. 26896-48-0 or 26160-83-8), trimethylolpropane (CAS no. 77-99-6), dendritic, hydroxy-functional polymers (CAS no. 326794-48-3 or 462113-22-0), polycaprolactone triols (CAS no. 37625-56-2), and polycaprolactone tetrols (CAS no. 35484-93-6).

12. The insulation material as claimed in claim 1, wherein the curing catalyst is present in an amount of less than 10 wt %.

13. The insulation material as claimed in claim 1, wherein the tape adhesive is present in an amount in a range from 1 to 30 wt %.

14. The insulation material as claimed in claim 1, wherein the carrier comprises a film, a woven material, and/or a nonwoven material.

15. The insulation material as claimed in claim 1, wherein the carrier comprises a perforated film.

16. The insulation material as claimed in claim 1, further comprising a particulate barrier material.

17. The insulation material as claimed in claim 1, wherein the particulate barrier material comprises platelet-shaped barrier material particles.

18. The insulation material as claimed in claim 16, wherein the particles of the barrier material include a coating.

19. The insulation material as claimed in claim 18, wherein the coating comprises a metal oxide.

20. The insulation material as claimed in claim 18, wherein the coating comprises doping.

21-22. (canceled)

Description

DETAILED DESCRIPTION

[0063] Some embodiments of the teachings herein may include a solid insulation material which can be used together with an anhydride-free impregnating agent for the preparation of an insulation system in a vacuum impregnation process, wherein said solid insulation material comprises a carrier, a barrier material, a curing catalyst and a tape adhesive, the curing catalyst and the tape adhesive being inert to one another but, under the conditions of the vacuum impregnation, reacting with an anhydride-free impregnating agent with gelling times of 1 h to 15 h at the impregnation temperature, the curing catalyst being obtainable by reaction of at least one 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups. Some embodiments may include the use of the insulation system produced in this way in electrical machines, e.g., in rotating electrical machines in the medium- and high-voltage sector, and also in electrical switchgear, medium- and high-voltage applications, bushings, transformer bushings, generator bushings and/or HVDC bushings, and in corresponding semifinished products. Finally, electrical machines in the medium- and high-voltage sector and electrical switchgear, medium- and high-voltage applications, bushings, transformer bushings, generator bushings and/or HVDC bushings, and corresponding semifinished products, may include such an insulation system.

[0064] Although the curing catalyst can be obtained by reaction at least of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups, it can also be produced according to other desired synthesis routes. The curing catalyst is for example merely the adduct of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups. In some embodiments, the curing catalyst, which is for example an adduct of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups, has a nitrogen density D in the range from, for example, 1 to 15 mmol/g; D is especially in the range from

1.Math.10.sup.3mol/g<D<13.Math.10.sup.3 mol/g,

from 2.5*10.sup.3mol/g to 10*10.sup.3 mol/g and from 4.5.Math.10.sup.3 mol/g to 9.Math.10.sup.3 mol/g. The molar nitrogen density D, that is mass-specific and capable of polymerization, given here is defined by the unit 10.sup.3=mol/g (corresponding to a thousandth of a mole per gram), which gives the content of nitrogen atoms with non-aromatic and concurrently non-bonding electron pairs per molecule. For example, the nitrogen density of the following compound, which discloses a curing catalyst according to the prior art,

##STR00001##

Structure I: Conventional Curing Catalyst According to the Prior Art

[0065] can be determined as follows: the molar mass of the molecule depicted, which represents a conventional curing catalyst according to the prior art, is M=638.89 g/mol. It has 3 nitrogen electron pairs capable of polymerization and hence for example the reference nitrogen density of 3 mol/638.89 g=4.7.Math.10.sup.3 mol/g.

[0066] In some embodiments, a curing catalyst is an adduct of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups. It is possible to produce a curing catalyst in mica papers containing binder which can be modified such that it becomes vacuum-stable at temperatures from 50-80 C. For example, such a curing catalyst has a vapor pressure of less than 10.sup.4 mbar at 70 C., and also a suitable dynamic viscosity.

[0067] In some embodiments, the curing catalyst exhibits a dynamic viscosity in the range from 1 to 10000 Pa.Math.s, especially from 5 to 5000 Pa.Math.s, or in the range from 10 to 3000 Pa.Math.s.

[0068] In some embodiments, the curing catalyst exhibits a vapor pressure at the impregnation temperature of less than 10.sup.1 mbar, especially at 70 C. in the range from 10.sup.2 mbar to 10.sup.8 mbar, from 10.sup.3 mbar to 10.sup.7 mbar, or from 10.sup.4 mbar to 10.sup.6 mbar.

[0069] A curing catalyst can be obtained by reaction at least of a 1H-imidazole and/or 1H-imidazole derivative with a compound containing oxirane groups, such as obtained via an addition reaction, as represented schematically below:

##STR00002##

Reaction Equation I: Imidazole Derivative Addition Reaction

[0070] Wherein, n=1-4; R.sub.1, R.sub.2, R.sub.3=hydrogen, alkyl and/or aryl; R is the molecular radical of the compound containing oxirane groups, i.e. for example a glycidyl reactant compound.

##STR00003##

Reaction Equation II: Pyrazole Derivative Addition Reaction

[0071] wherein, n=1-4; R.sub.1, R.sub.2, R.sub.3=hydrogen, alkyl and/or aryl; R is the molecular radical of the compound containing oxirane groups, i.e. for example the glycidyl reactant compound.

[0072] The table below shows a summary of possible reactants for preparing the curing catalyst, for example according to one of the mechanisms shown in the reaction equations I and/or II. The rows in the table give exemplary reactants containing oxirane groups and the columns give exemplary 1H-imidazole and/or 1H-imidazole derivatives: In particular, the abbreviations used in the columns have the following meanings:

[0073] Im: 1H-imidazole;

[0074] 2m-Im: 1H-2-methylimidazole;

[0075] 2e-Im: 1H-2-ethylimidazole;

[0076] 2e-4m-Im: 1H-2-ethyl-4-methylimidazole;

[0077] 4e-2Ph-Im: 1H-4-ethyl-2-phenylimidazole, and

[0078] 3,5m-Pyr: 1H-3,5-dimethylpyrazole.

[0079] The numerical values given correspond in each case to the nitrogen density D of the curing catalyst, i.e. of the respective addition product, as described above. As compounds containing oxirane groups, for example glycidyl ether and/or glycidyl ester compounds are used. Exemplary compounds are listed in the following table, with ester derivatives and/or other derivatives of the compounds containing oxirane groups mentioned by way of example here that are obvious to those skilled in the art in all cases also being incorporated within.

TABLE-US-00001 TABLE 1 Examples of reactants used for preparing the curing catalyst CAS no. N density D in [10.sub.3 mol/g] product, when using Reactant compound Reactant Im 2m-Im 2e-Im 2e-4m-Im 4m-2Ph-Im 3,5m-Pyr 2-Ethylhexyl glycidyl ether 2461-15-6 3.93 3.73 3.54 3.37 2.90 3.54 Allyl glycidyl ether 106-92-3 7.99 7.19 6.53 5.98 4.65 6.53 Glycidyl isopropyl ether 4016-14-2 5.43 5.04 4.71 4.42 3.64 4.71 Glycidyl methyl ether 64491-70-9 6.40 5.88 5.43 5.04 4.06 5.43 Ethyl glycidyl ether 4016-11-9 5.88 5.43 5.04 4.71 3.84 5.04 Benzyl glycidyl ether 2930-05-4 4.31 4.06 3.84 3.64 3.10 3.84 tert.-Butyl glycidyl ether 7665-72-7 n-Butyl glycidyl ether 2426-08-6 5.04 4.71 4.42 4.16 3.47 4.42 Glycidyl-2-methylphenyl ether 2210-79-9 4.31 4.06 3.84 3.64 3.10 3.84 Furfuryl glycidyl ether 5380-87-0 4.50 4.23 4.00 3.78 3.20 4.00 tert.-Butyldimethylsilylglycidyl ether 124150-87-4 3.90 3.70 3.52 3.35 2.89 3.52 2-Biphenyly1 glycidyl ether 7144-65-2 3.40 3.24 3.10 2.97 2.60 3.10 Bisphenol A- 76002-91-0 2.34 2.27 2.20 2.13 1.94 2.20 (2,3-dihydroxypropyhglycidyl ether n-Octyl glycidyl ether 68609-96-1 3.93 3.73 3.54 3.37 2.90 3.54 n-Decyl glycidyl ether 3.54 3.37 3.22 3.08 2.69 3.22 Glycidyl propargyl ether 18180-30-8 5.55 5.15 4.80 4.50 3.70 4.80 Glycidyl-4-methoxyphenyl ether 2211-94-1 4.03 3.81 3.62 3.44 2.96 3.62 Glycidyl-4-nonylphenyl ether 6178-32-1 2.90 2.79 2.68 2.59 2.30 2.68 Glycidyl hexadecyl ether 15965-99-8 2.73 2.63 2.53 2.45 2.19 2.53 Glycidyl trityl ether 65291-30-7, 2.60 2.51 2.42 2.34 2.11 2.42 129940-50-7 Dodecyl glycidyl ether 68609-97-2 3.22 3.08 2.95 2.84 2.50 2.95 Tetradecyl ether 2.95 2.84 2.73 2.63 2.33 2.73 Phenyl glycidyl ether 122-60-1, 4.58 4.06 3.84 3.24 4.06 71031-02-2, 71031-03-3 Poly(ethylene glycol)diglycidyl ether 72207-80-8 3.14 3.01 2.89 2.78 2.45 2.89 (Mw~500) Glycidyl methacrylate 106-91-2 7.19 6.53 5.98 5.52 4.36 5.98 Resorcinol diglycidyl ether 101-90-6 5.58 5.18 4.83 4.52 3.71 4.83 Diethylene glycol diglycidyl ether 4206-61-5 5.64 5.23 4.87 4.56 3.74 4.87 Glycidyl butyrate 60456-26-0, 4.71 4.42 4.16 3.93 3.31 4.16 65031-96-1 Glycidyl acrylate 106-90-1 7.57 6.84 6.24 5.74 4.50 6.24 Glycidol 556-52-5 7.03 6.40 5.88 5.43 4.31 5.88 Neopentylglycol diglycidyl ether 17557-23-2 5.67 5.26 4.90 4.58 3.75 4.90 Diglycidyl ether 2238-07-5 7.51 6.79 6.20 5.71 4.48 6.20 Bisphenol A diglycidyl ether 1675-54-3 4.20 3.96 3.75 3.57 3.05 3.75 Glycerol diglycidyl ether 27043-36-3 5.88 5.43 5.04 4.71 3.84 5.04 1,2-Propanediol diglycidyl ether 16096-30-3 6.17 5.68 5.26 4.90 3.96 5.26 1,4-Butanediol diglycidyl ether 2425-79-8 5.91 5.46 5.07 4.73 3.86 5.07 1,4-Cyclohexanedimethanol diglycidyl ether 14228-73-0 5.10 4.76 4.46 4.20 3.49 4.46 Bisphenol F diglycidyl ether 2095-03-6 4.46 4.20 3.96 3.75 3.18 3.96 Poly(propylene glycol)diglycidyl ether 26142-30-3 3.87 3.68 3.49 3.33 2.87 3.49 (Mw~380) Trimethylolpropane triglycidyl ether 3454-29-3 5.92 5.47 5.08 4.74 3.86 5.08 Tris(4-hydroxyphenyl)methane triglycidyl ether 66072-38-6 4.51 4.24 4.01 3.79 3.21 4.01 Trimethylolethane triglycidyl ether 68460-21-9 6.09 5.61 5.20 4.85 3.93 5.20 Tris(2,3-epoxypropyhisocyanurate 2451-62-9 5.98 5.52 5.12 4.78 3.89 5.12 Triglycidyl-para-aminophenol 28768-32-3 6.23 5.73 5.30 4.94 3.99 5.30 triglycidyl-meta-aminophenol Pentaerythritol tetraglycidyl ether 3126-63-4 6.32 5.81 5.37 4.99 4.03 5.37 Tetraglycidyl-4,4-diaminodiphenylmethane 28768-32-3 5.76 5.33 4.96 4.63 3.79 4.96 3,4-Epoxycyclohexylmethyl-3,4- 2386-87-0 5.15 4.80 4.50 4.23 3.52 4.50 epoxycyclohexanecarboxylate

Example: Synthesis of the Trimethylolpropane Triglycidyl Ether-Tris-(1H-2-methylimidazole) Reactant

[0080] Technical grade trimethylolpropane triglycidyl ether in 5% molar deficiency relative to the 1H-imidazole derivative were added slowly dropwise by means of a dropping funnel, with stirring, into a three-necked flask with reflux condenser in which 5 g of 1H-2-methylimidazole had been initially charged in 20 ml toluene at room temperature and had been dissolved under reflux for 10 min at 130 C.

[0081] The mixture was then refluxed for a few hours. Subsequently, an orange-colored, clear, highly viscous liquid was able to be obtained, which was dried under vacuum at 50-100 C.

[0082] A 5% (w/w) admixture to distilled Bisphenol A diglycidyl ether at 70 C. gave gelation and anionic curing. The same procedure was carried out with trimethylolpropane triglycidyl ether-tris(1H-2-ethyl-4-methylimidazole) reactant, neopentyl diglycidyl ether-bis(1H-2-ethyl-4-methylimidazole) reactant and bisphenol F diglycidyl ether-bis(1H-2-methylimidazole) reactant, with the distilled bisphenol F diglycidyl ether also being predissolved in toluene.

[0083] As tape adhesive, in the presence of the abovementioned reactants 1H-imidazole and/or 1H-imidazole derivatives with compounds containing oxirane groups as curing catalyst, use is preferably made of a tape adhesive as described in DE 102015205328.8, the disclosure content of which is hereby incorporated into the subject matter of the present description. Furthermore, for example a compound selected from the following group may be used in the solid insulation material:

[0084] tricyclomethane dimethanol (CAS no. 26896-48-0 or 26160-83-8),

[0085] trimethylolpropane (CAS no. 77-99-6),

[0086] dendritic, hydroxy-functional polymers (CAS no. 326794-48-3 or 462113-22-0),

[0087] polycaprolactone triols (CAS no. 37625-56-2), and/or

[0088] polycaprolactone tetrols (CAS no. 35484-93-6).

[0089] The tape adhesive connects the at least one carrier and the barrier material in the solid insulation material. It is present in the solid insulation material in an amount in the range from 1 to 30 wt %, 2 to 15 wt %, or 5 to 10 wt %. The carrier in the solid insulation material is in the form of a woven material, such as glass fiber woven material, or a nonwoven material, especially a polyester nonwoven, paper and/or film. The carrier may also be in the form of a perforated film.

[0090] In some embodiments, the particulate barrier material is located at, in and/or on this carrier in the solid insulation material. The barrier material may be at least partially in platelet form. Mica can especially be used as barrier material. In some embodiments, a coated particulate barrier material is used. This can especially be a metal oxide-coated particulate barrier material, for example tin oxide, zinc oxide or titanium oxide-coated particles.

[0091] In some embodiments, a doped coating of the particulate, especially platelet-shaped barrier material is provided. The tape adhesive connects the at least one carrier and the barrier material in the solid insulation material. It is present in the solid insulation material in an amount in the range from 1 to 30 wt %, 2 to 15 wt %, or 5 to 10 wt %.

[0092] In some embodiments, the curing catalyst, also referred to as tape curing catalyst or tape accelerator is present in the solid insulation material in a concentration of less than 10 wt %, for example from 0.001 wt % to 7.5 wt %, in the range from 0.01 wt % to 5 wt %, or from 0.1 wt % to 3.5 wt %, such that gelling times of several hours can be produced.

[0093] In some embodiments, the curing catalyst initiates the polymerization of the impregnation resin at temperatures in the range from 20 C. to 100 C., from 50 C. to 80 C., or from 55 C. to 75 C.

[0094] In order to achieve the targeted storage stability in the solid insulation material, for example at room temperature and especially for several hours of continuously maintained vacuum and impregnation temperature, the curing catalyst is comparatively inert to the tape adhesive material. This is especially also the case under the conditions of maintained vacuum and/or impregnation temperature, which are for example in the range between 20 C. and 100 C., between 50 C. to 80 C., or between 55 C. to 75 C. Suitable as tape adhesive are, for example, diols, triols and/or polyols.