(19)

(11)

EP 0 433 423 A1

(12)

(43) Date of publication: 26.06.1991 Bulletin 1991/26 (21) Application number: 90910150.0 (22) Date of filing: 09.07.1990

(51) International Patent Classification (IPC):  C22B 1/ 16( . ) C22B 1/ 244( . ) C22B 1/ 20( . ) (86) International application number: PCT/GB1990/001054 (87) International publication number: WO 1991/000930 (24.01.1991 Gazette 1991/03)

(84) Designated Contracting States: BE DE GB NL SE (30) Priority: 07.07.1989 GB 19890015639 (71) Applicant: ALLIED COLLOIDS LIMITED Bradford, West Yorkshire BD12 0JZ (GB)	(72) Inventor: FIELD, John, Rodney Halifax West Yorkshire HX3 8NX (GB) (74) Representative: Lawrence, Peter Robin Broughton, et al  GILL JENNINGS & EVERY, Broadgate House, 7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)