(19)

(11)

EP 0 604 452 A1

(12)

(43) Date of publication: 06.07.1994 Bulletin 1994/27 (21) Application number: 92916647.0 (22) Date of filing: 03.08.1992

(51) International Patent Classification (IPC):  C22B 1/ 244( . ) (86) International application number: PCT/GB1992/001432 (87) International publication number: WO 1993/003189 (18.02.1993 Gazette 1993/05)

(84) Designated Contracting States: NL SE (30) Priority: 02.08.1991 GB 19910166983 (71) Applicant: ALLIED COLLOIDS LIMITED Bradford, West Yorkshire BD12 0JZ (GB)	(72) Inventors: FIELD, John, Rodney 2 Leyburn Avenue Hipperholme West Yorkshire HX3 8NX (GB) ALLEN, Anthony, Peter Shipley West Yorkshire BD18 3EZ (GB) (74) Representative: Lawrence, Peter Robin Broughton  GILL JENNINGS & EVERY, Broadgate House, 7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)