(19)

(11)

EP 0 611 401 A1

(12)

(43) Date of publication: 24.08.1994 Bulletin 1994/34 (21) Application number: 92923892.0 (22) Date of filing: 20.11.1992

(51) International Patent Classification (IPC):  C25B 1/ 30( . ) C25B 1/ 13( . ) C25B 9/ 06( . ) C02F 1/ 461( . ) C25B 9/ 00( . ) C25B 15/ 02( . ) (86) International application number: PCT/GB1992/002157 (87) International publication number: WO 1993/011281 (10.06.1993 Gazette 1993/14)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL SE (30) Priority: 03.12.1991 GB 19910025680 (71) Applicant: IMPERIAL CHEMICAL INDUSTRIES PLC London SW1P 3JF (GB)	(72) Inventor: BULLEN, Shaun Northwich Cheshire CW8 1AP (GB) (74) Representative: Collingwood, Anthony Robert  Intellectual Property Department ICI Chemicals & Polymers Ltd P.O. Box 11 The Heath Runcorn Cheshire WA7 4QE Runcorn Cheshire WA7 4QE (GB)