Storage-stable impregnating resins and electrical insulating tapes

1. An anhydride-free impregnating resin for an electrical insulation body, wherein the impregnating resin comprises:

an epoxy resin, a hardener and nanosize and/or microsize inorganic particles,

wherein the hardener is selected from the group consisting of a substituted guanidine, an aromatic diamine, an N-acylimidazole, a metal salt complex of an imidazole, a carboxylic hydrazide, a triazine derivative, melamine, a melamine derivative, a cyanoacetyl compound, an N-cyanoacylamide compound, an acylthiopropylphenol, a urea derivative, an aliphatic diamine, a cycloaliphatic diamine, an aliphatic polyamine, a cycloaliphatic polyamine and mixtures thereof,

wherein the hardener is suspended in a solid state in the epoxy resin.

2. The impregnating resin as claimed in claim 1 ,

wherein the substituted guanidine is dicyandiamide.

3. The impregnating resin as claimed in claim 1 ,

wherein the hardener is suspended in the form of particles in the epoxy resin.

4. The impregnating resin as claimed in claim 1 ,

wherein the hardener is present in an amount of 1% by weight-15% by weight based on the epoxy resin.

5. The impregnating resin as claimed in claim 1 ,

wherein the inorganic particles comprise aluminum oxide, aluminum hydroxide, silicon dioxide, titanium dioxide, rare earth oxide, alkali metal oxide, metal nitride and/or sheet silicates, in particular exfoliated or partially exfoliated sheet silicates.

6. The impregnating resin as claimed in claim 1 ,

wherein the inorganic particles are present in an amount of 15% by weight-25% by weight based on the epoxy resin.

7. The impregnating resin as claimed in claim 3 ,

wherein the hardener is suspended in the form of particles having a particle size of 1 μm-100 μm in the epoxy resin.

8. The impregnating resin as claimed in claim 4 ,

wherein the hardener is present in an amount of 4% by weight-10% by weight based on the epoxy resin.

9. The impregnating resin as claimed in claim 6 ,

wherein the inorganic particles are present in an amount of 17% by weight based on the epoxy resin.

10. An impregnatable electrical insulation tape for an electrical insulation body, comprising:

a hardener in a solid state applied to the electrical insulation tape.

11. The electrical insulation tape as claimed in claim 10 ,

wherein the hardener has been applied to a first side of the electrical insulation tape and a catalyst has been applied to a second side of the electrical insulation tape which faces away from the first side.

12. The electrical insulation tape as claimed in claim 11 ,

wherein the catalyst is selected from the group consisting of zinc naphthenate, cobalt naphthenate, zinc octoate, cobalt octoate, an imidazole, a tertiary amine, an aluminum trisalkylacetoacetate, aluminum trisacetylacetonate, aluminum alkoxide, aluminum acylate, a tetralkylammonium benzoate and mixtures thereof.

13. The electrical insulation tape as claimed in claim 10 ,

wherein the hardener is selected from the group consisting of a substituted guanidine, an aromatic diamine, an N-acylimidazole, a metal salt complex of an imidazole, a carboxylic hydrazide, a triazine derivative, melamine, a melamine derivative, a cyanoacetyl compound, an N-cyanoacylamide compound, an acylthiopropylphenol, a urea derivative, an aliphatic diamine, a cycloaliphatic diamine, an aliphatic polyamine, a cycloaliphatic polyamine and mixtures thereof.

14. The impregnatable electrical insulation tape of claim 10 , further comprising a hardener-free liquid resin impregnated into the impregnatable electrical insulation tape, forming a solid/liquid two-phase system of hardener/resin in the impregnatable electrical insulation tape.

15. A process for producing an electrical insulation body, comprising:

a1) wrapping an electrical insulation tape around an electrical conductor,

b) impregnating the electrical insulation tape of step a1) with an impregnating resin to form a solid/liquid two-phase system of hardener/resin in the electrical insulation tape; and

c) curing the impregnating resin.

16. The process as claimed in claim 15 , further comprising:

a2) mixing the epoxy resin with the inorganic particles;

wherein the impregnating resin is produced in step b) by contacting the mixture from step a2) with the electrical insulation tape from step a1).

17. The process of claim 15 , further comprising:

prior to step a1), applying the hardener to the electrical insulation tape, and

impregnating the electrical insulation tape in step b) with a hardener-free impregnating resin.

18. The process of claim 17 , further comprising:

applying the hardener to the electrical insulation tape in a liquid state, and

allowing the hardener to transform to a solid state prior to step a1).