(19)

(11)

EP 0 956 335 A1

(12)

(43) Date of publication: 17.11.1999 Bulletin 1999/46 (21) Application number: 97945973.0 (22) Date of filing: 28.11.1997

(51) International Patent Classification (IPC):  C12H 1/ 04( . ) C12H 1/ 044( . ) C01B 33/ 12( . ) (86) International application number: PCT/GB1997/003281 (87) International publication number: WO 1998/028401 (02.07.1998 Gazette 1998/26)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 20.12.1996 GB 19960026611 (71) Applicant: CROSFIELD LIMITED Warrington, Cheshire WA5 1AB (GB)	(72) Inventors: McKEOWN, Ian, Patrick Liverpool L19 3QZ (GB) GLEAVES, Michael, Thomas London N5 2BJ (GB) (74) Representative: Collingwood, Anthony Robert, et al  ICI Group Intellectual Property P.O. Box 11 The Heath Runcorn Cheshire WA7 4QE Runcorn Cheshire WA7 4QE (GB)