(19)
(11) EP 0 056 675 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
04.08.1982 Bulletin 1982/31

(43) Date of publication A2:
28.07.1982 Bulletin 1982/30

(21) Application number: 82200062

(22) Date of filing: 19.01.1982
(84) Designated Contracting States:
AT BE DE FR GB IT NL SE

(30) Priority: 19.01.1981 JP 702881

(71) Applicant: Nippon Paint Co., Ltd.
 ()

(72) Inventors:
  • Nakatani, Nobuo
     ()
  • Tsuzuki, Tooru
     ()
  • Shimizu, Hideo
     ()

   


(54) Pretreatment composition for phosphatising ferrous metals, and method of preparing the same


(57) An aqueous composition for the treatment of ferrous metal surfaces is a solution comprising:

(a) titanium compound in amount from 1 to 100 parts per million by weight, measured as titanium;

(b) phosphate and/or acid phosphate in amount totalling from 50 to 1500 parts per million by weight, measured as PO4;

(c) pyrophosphate in amount from 10 to 300 parts per million by weight, measured as P2O7; and

(d) carbonate and/or acid carbonate in amount totalling 20 to 1500 parts per million by weight, measured as C03;


the solution having a pH from 8.5 to 9.5.





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