(19)

(11)

EP 0 586 440 A1

(12)

(43) Date of publication: 16.03.1994 Bulletin 1994/11 (21) Application number: 92910427.0 (22) Date of filing: 22.05.1992

(51) International Patent Classification (IPC):  C11D 1/ 75( . ) C11D 17/ 00( . ) C11D 3/ 20( . ) (86) International application number: PCT/GB1992/000943 (87) International publication number: WO 1992/020772 (26.11.1992 Gazette 1992/29)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU MC NL (30) Priority: 24.05.1991 GB 19910011219 12.02.1992 GB 19920002884 (71) Applicant: IMPERIAL CHEMICAL INDUSTRIES PLC London SW1P 3JF (GB)	(72) Inventor: HEPWORTH, Paul Upper Poppleton, York YO2 6LH (GB) (74) Representative: Roberts, Jonathan Winstanley, et al  Intellectual Property Department ICI Chemicals & Polymers Ltd P.O. Box 11 The Heath Runcorn Cheshire WA7 4QE Runcorn Cheshire WA7 4QE (GB)