(19)
(11) EP 0 425 271 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.03.1993 Bulletin 1993/09

(43) Date of publication A2:
02.05.1991 Bulletin 1991/18

(21) Application number: 90311659.8

(22) Date of filing: 24.10.1990
(51) International Patent Classification (IPC)5: C23C 22/83, C23F 11/14
(84) Designated Contracting States:
AT BE DE DK ES FR GB IT NL SE

(30) Priority: 25.10.1989 US 426355

(71) Applicant: PPG INDUSTRIES, INC.
Pittsburgh Pennsylvania 15272 (US)

(72) Inventor:
  • Gray, Ralph C.
    Allison Park, PA 15101 (US)

(74) Representative: Taylor, Phillip Kenneth et al
W.P. THOMPSON & CO. Coopers Building Church Street
Liverpool L1 3AB
Liverpool L1 3AB (GB)


(56) References cited: : 
   
       


    (54) Process for rinsing phosphate conversion coatings with compositions containing an S-triazine compound


    (57) The invention relates to an aqueous pretreating composition for application to a metal surface, characterised in that said composition has a pH of about 3.4 to 6.0 and comprises at least about .01 percent by weight based on the total weight of the composition of an S-triazine compound having at least one hydroxyl group on a carbon atom of the triazine ring.
    The invention also provides a process of pretreating a metal surface characterised by applying to the metal surface at a temperature of 30oC to 80oC an aqueous composition having a pH of about 3.4 to 6.0, said composition comprising at least 0.01 percent by weight based on the total weight of the composition of an S-triazine compound having at least one hydroxyl group on a carbon atom of the triazine ring. Preferably, the aqueous composition of the S-triazine compound is employed as a final rinse over a metal surface comprising a conversion coating such as a phosphate conversion coating.





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