FIELD: insulating coating production.
SUBSTANCE: inventions group relates to a method for producing a treatment solution for forming an insulating coating, a method for producing a steel sheet coated with an insulating coating and a device for producing said solution. A method for preparing a treatment solution for forming an insulating coating containing phosphoric acid and/or a phosphate salt and one or more particulate metal compounds includes mixing solution A and solution B, and stirring with a high-speed stator-type turbine stirrer such that the peripheral speed turbine reaches 10 m/s or more within 60 seconds after mixing solution A and solution B. Solution A contains, in terms of PO43-, 0.20 mol/L or more and 10 mol/L or less of phosphoric acid and/or phosphate salt and contains, in terms of metal, less than 0.50 mol/L of metal compounds in the form of particles. Solution B contains, in terms of metal, 0.50 mol/L or more and 20.0 mol/L or less of particulate metal compounds and contains, in terms of PO43-, less than 0.20 mol/L of phosphoric acid and/or phosphate salt.
EFFECT: invention provides a treatment solution to form an insulating coating having a high applied tension and resistance to moisture absorption.
17 cl, 3 dwg, 4 tbl, 4 ex
