(19)

(11)

EP 0 523 169 A1

(12)

(43) Date of publication: 20.01.1993 Bulletin 1993/03 (21) Application number: 91908049.0 (22) Date of filing: 03.04.1991

(51) International Patent Classification (IPC):  C01B 15/ 10( . ) C11D 7/ 54( . ) C11D 17/ 06( . ) C11D 3/ 39( . ) C11D 17/ 00( . ) D06L 3/ 02( . ) (86) International application number: PCT/US1991/002308 (87) International publication number: WO 1991/015423 (17.10.1991 Gazette 1991/24)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 06.04.1990 US 19900505800 (71) Applicant: FMC Corporation Philadelphia Pennsylvania 19103 (US)	(72) Inventors: COPENHAFER, William, Clark Yardley, PA 19067 (US) GUILIANO, Basil, Anthony Lawrenceville, NJ 08648 (US) HILLS, William, Avery Lawrenceville, NJ 08648 (US) JUELKE, Charles, Vincent Belle Mead, NJ 08502 (US) TOMKO, Stephen Trenton, NJ 08619 (US) (74) Representative: W.P. Thompson & Co.  Coopers Building, Church Street Liverpool L1 3AB Liverpool L1 3AB (GB)