Modified polyolefin fibres
Polyolefin material comprising a core portion composed of at least one of polypropylene produced using a Ziegler-Natta catalyst, isotactic homopolymer or random copolymer of propylene produced using a metallocene catalyst or polyethylene, preferably linear low density polyethylene, and an external layer composed of the core portion material additionally blended with a syndiotactic polypropylene, the syndiotactic polypropylene including at least one particulate material or chemical additive.
1 - 17 . (canceled)
18 . A polyolefin fiber product comprising:
(a) a core portion of said fiber product formed of a first polyolefin component selected from a group consisting of a propylene polymer produced with a Ziegler-Natta catalyst, a propylene polymer produced with a metallocene catalyst, a polyethylene resin and mixtures thereof; and
(b) an external surface layer of said fiber product formed of a blend of said first polyolefin component and a syndiotactic propylene polymer incorporating at least one filler additive selected from a group consisting of particulate material, a chemical additive and mixtures thereof.
19 . The polyolefin fiber product of claim 18 wherein said filler additive is an anti-microbial agent.
20 . The polyolefin fiber product of claim 18 wherein said filler additive is a flame retardant agent.
21 . The polyolefin fiber product of claim 18 wherein said filler additive is an anti-static agent.
22 . The polyolefin fiber product of claim 18 wherein said filler additive is an anti-ultraviolet agent.
23 . The polyolefin fiber product of claim 18 wherein said filler additive is an anti-algae agent.
24 . The polyolefin fiber product of claim 18 wherein said syndiotactic propylene polymer is present in said external surface layer blend in an amount within the range of 1-20 wt. %.
25 . The polyolefin fiber product of claim 19 wherein said syndiotactic propylene polymer is present in said external surface layer blend in an amount of no more than 15 wt. %.
26 . The fiber product of claim 18 wherein said first polyolefin component comprises a metallocene-produced polyethylene or a linear low-density polyethylene.
27 . The fiber product of claim 26 wherein said first polyolefin component is a linear low density polypropylene.
28 . The fiber product of claim 18 wherein said first polyolefin component comprises a polypropylene prepared with a Ziegler-Natta catalyst or prepared with a metallocene catalyst.
29 . The fiber product of claim 18 wherein said syndiotactic propylene polymer has a racemic pentad content of at least 70%.
30 . The fiber product of claim 29 wherein said syndiotactic propylene polymer has a bimodal molecular weight distribution.
31 . The polyolefin fiber product of claim 18 wherein said filler additive is a particulate material.
32 . The fiber product of claim 31 wherein the predominant portion of particulate material in said fiber product is in the external surface layer of said fiber product.
33 . The fiber product of claim 32 wherein said particulate material comprises electrically conductive particles in a concentration in said surface layer at least as great as the percolation threshold for electrical conductivity.
34 . The fiber product of claim 32 wherein said particulate material comprises heat conductive particles in a concentration in said surface layer at least as great as the percolation threshold for thermal conductivity.
35 . The fiber product of claim 32 wherein said particulate material has a density greater than the density of said syndiotactic propylene polymer.
36 . The fiber product of claim 32 wherein said particulate material is selected from the group consisting of glass fibers, carbon fibers, alumina particles, calcium carbonate particles, carbon black particles, silicon particles, graphite particles and mixtures thereof.
37 . A process for producing a polyolefin fiber product comprising:
(a) providing a core polymer material portion of said fiber product comprising a polyolefin component selected from a group consisting of a propylene polymer produced with a Ziegler-Natta catalyst, an isotactic propylene polymer produced with a metallocene catalyst, a polyethylene resin and mixtures thereof;
(b) providing a syndiotactic propylene polymer incorporating a particulate material;
(c) dry blending said syndiotactic propylene polymer with said core material polymer to produce a blend; and
(d) extruding said blend to produce a polymer fiber product comprising a core layer and a surface layer with said surface layer containing from 50-90 wt. % of the syndiotactic propylene polymer in said fiber product.
38 . The process of claim 37 wherein said polyolefin component comprises a metallocene-produced polyethylene or a linear low-density polyethylene.
39 . The process of claim 38 wherein said polyolefin component is a linear low density polypropylene.
40 . The process of claim 37 wherein said syndiotactic propylene polymer has a racemic pentad content of at least 70%.
41 . The process of claim 40 wherein said syndiotactic propylene polymer has a bimodal molecular weight distribution.