	US 11,859,316 B2
	Process for the production of fibers
Gaetan Henry, Bovesse (BE); Guillaume Pavy, Brussels (BE); John Bieser, Houston, TX (US); Hugues Haubruge, Walhain (BE); and Alain Standaert, Brussels (BE)
Assigned to TOTALENERGIES ONETECH BELGIUM, Seneffe (BE)
Filed by TOTALENERGIES ONETECH BELGIUM, Seneffe (BE)
Filed on Oct. 30, 2020, as Appl. No. 17/084,859.
Application 17/084,859 is a continuation of application No. 14/241,277, abandoned, previously published as PCT/EP2012/066677, filed on Aug. 28, 2012.
Claims priority of provisional application 61/528,910, filed on Aug. 30, 2011.
Claims priority of application No. 11182280 (EP), filed on Sep. 22, 2011.
Prior Publication US 2021/0047755 A1, Feb. 18, 2021
Int. Cl. C08F 2/02 (2006.01); C08F 4/6592 (2006.01); C08F 210/06 (2006.01); C08L 23/14 (2006.01); D01D 1/04 (2006.01); D01D 5/098 (2006.01); D01D 5/12 (2006.01); D01D 7/00 (2006.01); D04H 3/16 (2006.01); D01F 6/30 (2006.01); D01F 6/06 (2006.01); D01D 5/08 (2006.01); D04H 1/4291 (2012.01); D04H 3/007 (2012.01)

CPC D01F 6/30 (2013.01) [D01D 5/08 (2013.01); D01D 5/0985 (2013.01); D01F 6/06 (2013.01); D04H 1/4291 (2013.01); D04H 3/007 (2013.01); C08F 4/65922 (2013.01); C08F 4/65925 (2013.01); D10B 2321/022 (2013.01); Y10T 442/682 (2015.04)]

16 Claims

1. A process for the production of fibers comprising:

(a) polymerizing propylene and at least one comonomer in presence of a metallocene-based polymerization catalyst, to obtain a metallocene random copolymer of propylene and at least one comonomer;

(b) melt-extruding a polypropylene composition comprising the metallocene random copolymer obtained in step (a) to obtain a molten polypropylene stream;

(c) extruding the molten polypropylene stream of step (b) from capillaries of a spinneret, thus obtaining filaments of molten polypropylene; and

(d) subsequently rapidly reducing a diameter of the filaments to obtain a final diameter;

wherein said metallocene random copolymer has a comonomer content of from 1.2 wt % to 1.8 wt %, relative to a total weight of said metallocene random copolymer;

wherein the at least one comonomer is ethylene; and

wherein said metallocene random copolymer has a molecular weight distribution, defined as Mw/Mn and determined by gel permeation chromatography, of from 1.0 to 3.0, obtained without thermal or chemical degradation; a melt flow index of at least 25 dg/min and at most 50 dg/min, determined according to ISO 1133, condition L, at 230° C. and 2.16 kg; and a melting temperature T_melt, determined by Differential Scanning Calorimetry according to ISO 3146, of at most 140° C.