Patent ID: 11873408
Assignee: nan
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  H | IPC C  H

Claim 19:
20. A method for coating an electrical steel strip, comprising steps of:
applying a wet film of an aqueous chromium- and phosphate-free composition to at least a part of a surface of the electrical steel strip, which composition comprises one or more water glass solutions, each containing a silicate of the general empirical formula M2O·nSiO2, where n is a natural number of at least 2.5, but no greater than 4.5, and M is selected from sodium or potassium; the one or more water glass solutions comprising:
A) at least 15 wt. %, but no more than 40 wt. %, of silicates dissolved in water, calculated as SiO2; and
B) at least 4 wt. %, but no more than 15 wt. %, of sodium and/or potassium ions dissolved in water, calculated as Na and/or K;
the wet film further comprising
C) in total at least 1 wt. %, but no more than 10 wt. %, of water-insoluble oxide pigments, different from A) and B), selected from water-insoluble oxide pigments of the elements Mg, Al, Mn, Zn, Ti and/or Zr; and optionally further comprising water-insoluble oxide pigments of Ca and Si; and

drying the wet film on the surface of the electrical steel strip.