Coil and electrical strip or electrical sheet

Patent metadata

Field	Value
Publication number	US-2018122573-A1
Application number	US-201615561284-A
Country	US
Kind code	A1
Filing date	Mar 24, 2016
Priority date	Mar 24, 2015
Publication date	May 3, 2018
Grant date	—

Abstract

A coil and an electrical strip or electrical sheet with at least one heat-hardening hotmelt varnish, namely a baked enamel layer, provided on its flat sides, which has an epoxy resin base, at least one hardener, and at least one filler, are disclosed. In order to achieve a high storage stability and long-term temperature stability, the proposal is made for the filler of the baked enamel layer to have a metal carbonate, sulfate, sulfide, silicate, or phosphate or any mix of a plurality of these.

First claim

1 . An electrical strip or electrical sheet, comprising:
at least one heat-hardening hotmelt varnish, namely a baked enamel layer, provided on flat sides of the electrical strip or electrical sheet, which has an epoxy resin base, at least one hardener, and at least one filler, wherein the at least one filler of the baked enamel layer contains at least one of the group consisting of: a metal carbonate, sulfate, sulfide, silicate, phosphate and any combination thereof.

2 . The electrical strip or electrical sheet according to claim 1 , wherein the heat-hardening baked enamel layer contains 5 to 25% by volume of filler.

3 . The electrical strip or electrical sheet according to claim 2 , wherein the heat-hardening baked enamel layer contains:
6 to 10% by volume of hardener; and 74 to 85% by volume of epoxy resin as a base.

4 . The electrical strip or electrical sheet according to claim 1 , wherein the metal carbonate is calcium carbonate (CaCO 3 ).

5 . The electrical strip or electrical sheet according to claim 1 , wherein the metal sulfate is barium sulfate (BaSO 4 ).

6 . The electrical strip or electrical sheet according to claim 1 , wherein:
the metal sulfide is zinc sulfide (ZnS), the metal silicate is magnesium silicate (MgO 3 Si) or aluminum silicate, the metal phosphate is zinc phosphate Zn 3 (PO 4 ) 2 , or the mixture is lithopone.

7 . The electrical strip or electrical sheet according to claim 1 , wherein the filler has an average grain size of 0.6 to 3 μm.

8 . The electrical strip or electrical sheet according to claim 1 , wherein the hardener has a dicyandiamide base.

9 . The electrical strip or electrical sheet according to claim 1 , wherein the baked enamel layer has at least two hardeners that have different reactivities with the epoxy resin base.

10 . The electrical strip or electrical sheet according to claim 1 , wherein the epoxy resin base is bisphenol A.

11 . The electrical strip or electrical sheet according to claim 1 , wherein the electrical strip or electrical sheet has the heat-hardening baked enamel layer on both of its flat sides.

12 . A coil comprising the electrical strip or electrical sheet according to claim 1 , wherein the electrical strip or electrical sheet is wound.

13 . A method of increasing dimensional stability of a coil, comprising:
using at least one of the group consisting of: a metal carbonate, sulfate, sulfide, silicate, phosphate, and any combination thereof as a filler in a heat-hardening hotmelt varnish, namely a baked enamel layer, with an epoxy resin base and a hardener to coat an electrical strip or electrical sheet on at least one of its flat sides; and forming the coil from the coated electrical strip or electrical sheet.

14 . A method of increasing long-term temperature resistance of a laminated core; comprising:
using at least one of the group consisting of: a metal carbonate, sulfate, sulfide, silicate, phosphate, and any combination thereof as a filler in a heat-hardening hotmelt varnish, namely a baked enamel layer, with an epoxy resin base and a hardener to coat an electrical strip or electrical sheet on at least one of its flat sides; and forming the laminated core from the coated electrical strip or electrical sheet.

15 . The method according to claim 13 , comprising using 5 to 25% by volume of metal carbonate, sulfate, sulfide, silicate, phosphate or any mix of a plurality of these.

Assignees

• Voestalpine Stahl Gmbh

Inventors

• Fluch Ronald
• Tiefenthaller Roman

Classifications

• C21D8/1277

  involving a particular surface treatment (C21D8/1294 takes precedence) · CPC title

• C09D163/00

  Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins · CPC title

• C08G59/4021

  Ureas; Thioureas; Guanidines; Dicyandiamides · CPC title

• H01F5/02

  wound on non-magnetic supports, e.g. formers · CPC title

• H01F41/04 Primary

  for manufacturing coils {(coils for transformer or inductances H01F27/28)} · CPC title