Process of applying an insulating layer
US4756933A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1986 |
| Grant date | Jul 12, 1988 |
| Priority date | — |
| Expiry date | Jul 16, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A process is disclosed for applying to sheet steel an electrically insulating layer which permits mainly a satisfactory welding of the sheets when they have been blanked and stacked. The sheet steel is contacted with a treating liquor which contains a resin that is adapted to be diluted in an alkaline aqueous medium and also contains a fluoride of a polyvalent metal, particularly aluminum fluoride, in an amount of 0.1 to 80 parts by weight per 100 parts by weight resin. The treating liquor is subsequently dried and the sheet is subjected to a stress-relieving annealing, if required. In preferred embodiments of the invention a treating liquor is employed which additionally contains borates and/or dispersed particles comprising silicate and/or polymers and which is applied by means of rollers and is dried at 120.degree. to 350.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.