(19)

(11)

EP 0 511 261 A1

(12)

(43) Date of publication: 04.11.1992 Bulletin 1992/45 (21) Application number: 91902313.0 (22) Date of filing: 15.01.1991

(51) International Patent Classification (IPC):  C11D 3/ 12( . ) C11D 17/ 00( . ) (86) International application number: PCT/GB1991/000052 (87) International publication number: WO 1991/010720 (25.07.1991 Gazette 1991/17)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 15.01.1990 GB 19900000833 12.11.1990 GB 19900024563 (71) Applicant: S.B. CHEMICALS LIMITED Lisburn, Antrim BT27 5QB (GB)	(72) Inventors: HALL, Sean, Geoffrey Hillsborough Co. Down BT26 8HS (GB) McCULLINS, John, Thomas Belfast BT6 0NJ (GB) (74) Representative: Eyles, Christopher Thomas  W.P. THOMPSON & CO. Celcon House 289-293 High Holborn London WC1V 7HU London WC1V 7HU (GB)