(19)

(11)

EP 1 189 846 A1

(12)

(43) Date of publication: 27.03.2002 Bulletin 2002/13 (21) Application number: 00936210.4 (22) Date of filing: 23.05.2000

(51) International Patent Classification (IPC)7: C03C 13/00 (86) International application number: PCT/US0014/155 (87) International publication number: WO 0073/231 (07.12.2000 Gazette 2000/49)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 28.05.1999 US 136538 P (71) Applicant: PPG Industries Ohio, Inc. Cleveland, OH 44111 (US)	(72) Inventor: WALLENBERGER, Frederick, T. Allison Park, PA 15101 (US) (74) Representative: Sternagel, Fleischer, Godemeyer & PartnerPatentanwälte  Braunsberger Feld 29 51429 Bergisch Gladbach 51429 Bergisch Gladbach (DE)