(19)

(11)

EP 0 506 681 A1

(12)

(43) Date of publication: 07.10.1992 Bulletin 1992/41 (21) Application number: 90917071.0 (22) Date of filing: 31.10.1990

(51) International Patent Classification (IPC):  D01F 9/ 21( . ) D01F 9/ 30( . ) D02G 1/ 20( . ) D01F 9/ 22( . ) D02G 1/ 00( . ) (86) International application number: PCT/US1990/006312 (87) International publication number: WO 1992/007981 (14.05.1992 Gazette 1992/11)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (71) Applicant: THE DOW CHEMICAL COMPANY Midland, Michigan 48640 (US)	(72) Inventors: McCULLOUGH, Francis, P., Jr. Lake Jackson, TX 77566 (US) SNELGROVE, R., Vernon Damon, TX 77430 (US) PATTON, Robert, T. Lake Jackson, TX 77566 (US) (74) Representative: Smulders, Theodorus A.H.J., Ir., et al  Vereenigde Octrooibureaux Nieuwe Parklaan 97 NL-2587 BN 's-Gravenhage NL-2587 BN 's-Gravenhage (NL)