Self-Crimped Multi-Component Fibers and Methods of Making the Same
Self-crimped multi-component fibers (SMF) are provided that include (i) a first component comprising a first polymeric material, in which the first polymeric material comprises a first melt flow rate (MFR) that is less than 50 g/10 min; and (ii) a second component comprising a second polymeric material, in which the second component is different than the first component. The SMF includes one or more three-dimensional crimped portions. Also provided are nonwoven fabrics comprising a plurality of SMFs. Methods of manufacturing SMFs and nonwoven fabrics including SMFs are also provided.
1 . A method of forming a plurality of self-crimped multi-component fibers (SMFs), comprising:
(i) separately melting at least the first polymeric material to provide a first molten polymeric material and a second polymeric material to provide a second molten polymeric material, wherein the first polymeric material has a first melt flow rate (MFR) less than 50 g/10 min;
(ii) separately directing the first molten polymeric material and the second molten polymeric material through a spin beam assembly equipped with a distribution plate configured such that the separate first molten polymeric material and the second molten polymeric material combine at a plurality of spinnerette orifices to form molten multi-component filaments containing both the first molten polymeric material and the second molten polymeric material;
(iii) extruding the molten multi-component filaments from the spinnerette orifices into a quench chamber;
(iv) directing quench air from at least a first independently controllable blower into the quench chamber and into contact with the molten multi-component filaments to cool and at least partially solidify the multi-component filaments to provide at least partially solidified multi-component filaments;
(v) directing the at least partially solidified multi-component filaments and the quench air into and through a filament attenuator and pneumatically attenuating and stretching the at least partially solidified multi-component filaments;
(vi) directing the at least partially solidified multi-component filaments from the attenuator into a filament diffuser unit and allowing the at least partially solidified multi-component filaments to form one or more three-dimensional crimped portions to provide the plurality of SMFs; and
(vii) directing the plurality of SMFs through the filament diffuser unit and depositing the plurality of SMFs randomly upon a moving belt.
2 . The method of claim 1 , wherein the second polymeric material has a second melt flow rate (MFR) less than 50 g/10 min.
3 . The method of claim 1 , wherein the plurality of SMFs are bicomponent spunbond fibers.
4 . The method of claim 1 , wherein the plurality of SMFs comprises an average free crimp percentage from about 30% to about 300%.
5 . The method of claim 1 , wherein the one or more three-dimensional crimped portions include at least one discrete zig-zag configured crimped portion, at least one discrete helically configured crimped portion, or a combination thereof.
6 . The method of claim 1 , wherein the plurality of SMFs comprises a sheath/core configuration, a side-by-side configuration, a pie configuration, an islands-in-the-sea configuration, a multi-lobed configuration, or any combinations thereof.
7 . The method of claim 6 , wherein the sheath/core configuration comprises an eccentric sheath/core configuration including a sheath component and core component; wherein the core component defines at least a portion of an outer surface of the SMF having the eccentric sheath/core configuration.
8 . The method of claim 1 , wherein the first polymeric material comprises a first polyolefin composition and the second polymeric material comprises a second polyolefin composition.
9 . The SMF of claim 8 , wherein the second polyolefin composition comprises a second MFR from about 20 to about 48 g/10 min; and wherein the plurality of SMFs comprises a side-by-side configuration having a round cross-section.
10 . The method of claim 8 , wherein the first polyolefin composition comprises a first polypropylene and the second polyolefin composition comprises a second polypropylene and/or a second polyethylene.
11 . The method of claim 10 , wherein the first polypropylene has a lower degree of crystallinity than the second polypropylene and/or a second polyethylene.
12 . The method of claim 10 , wherein the first polyolefin composition comprises a blend of a polyolefin fraction A and a polyolefin fraction B; wherein the polyolefin fraction A accounts for more than 50% by weight of the first polyolefin composition and has a polyolefin fraction A-MFR being less than a polyolefin fraction B-MFR of the polyolefin fraction B.
13 . The method of claim 12 , wherein the first polyolefin composition has a MFR-Ratio between the polyolefin fraction B-MFR and the polyolefin fraction A-MFR from about 15:1 to about 100:1.
14 . The method of claim 12 , wherein the polyolefin fraction B comprises a meltblown polypropylene resin.
15 . The method of claim 12 , wherein the first polyolefin composition has a polydispersity value from about 3 to about 10.
16 . The method of claim 10 , wherein the polyolefin fraction B comprises from about 0.5% by weight to about 20% by weight of the first polyolefin composition.
17 . A method of forming a nonwoven fabric, comprising:
(i) forming a plurality of self-crimped multi-component fibers (SMFs) according to claim 1 to provide a first disposable-high-loft (DHL) nonwoven web; and
(ii) consolidating the first DHL to provide a first DHL nonwoven layer.
18 . The method of claim 17 , wherein consolidating the first DHL comprises mechanically bonding the plurality of SMFs.
19 . The method of claim 17 , wherein consolidating the first DHL comprises thermally bonding the plurality of SMFs.
20 . The method of claim 17 , further comprising forming or providing a second nonwoven layer and directly or indirectly bonding a first side of the second nonwoven layer to the first DHL nonwoven layer.