(19)

(11)

EP 0 643 763 A1

(12)

(43) Date of publication: 22.03.1995 Bulletin 1995/12 (21) Application number: 93910229.0 (22) Date of filing: 19.05.1993

(51) International Patent Classification (IPC):  C11D 3/ 39( . ) C11D 11/ 00( . ) C11D 3/ 395( . ) C11D 17/ 00( . ) (86) International application number: PCT/GB1993/001022 (87) International publication number: WO 1993/024604 (09.12.1993 Gazette 1993/29)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 29.05.1992 GB 19920011373 24.06.1992 GB 19920013342 (71) Applicant: BP Chemicals Limited London EC2M 7BA (GB)	(72) Inventors: LOVE, Barry Neil Beverley, North Humberside HU17 7ER (GB) YOUNG, Colin Hull HU8 8LH (GB) (74) Representative: Peet, Jillian Wendy  Gill Jennings & Every Broadgate House 7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)