Biconstituent polypropylene/polyethylene fibers

Claim 2

A blend of highly crystalline polypropylene and LLDPE, said blend being in the form of biconstituent fibers produced in a fiber-making process which uses and intensive mixer-extruder in melt-blending and melt-extruding said blend of highly crystalline polypropylene and LLDPE, said LLDPE being characterized as having a melt flow rate in the range of about 12 to about 120 gms/10 min. as measured in accordance with ASTM D-1238(E), said polypropylene being characterized as being a constant rheology grade, with the ratio of polypropylene/LLDPE being within the range of about 78/22 to about 55/45, and wherein said fibers have a size less than about 30 denier.

Claim 3

The blend of claim 1 wherein the LLDPE has a melt flow rate of about 50+20 gms/10 min.

Claim 4

The blend of claim 1 wherein the LLDPE is a copolymer of ethylene/1-octene wherein the 1-octene comprises about 3 to about 20 percent by weight of the copolymer.

Claim 5

The blend of claim 1 wherein the ratio of polypropylene/LLDPE is in the range of about 75/25 to about 35/65.

Claim 6

The blend of claim 1 wherein the ethylene comprises about 25 to about 35 weight percent ratio of polypropylene/LLDPE is in the range of about 72/28 to 68/32.

Claim 7

The blend of claim 1 wherein the LLDPE is a copolymer of ethylene and 1-octene and comprises about 28 to about 32 weight percent of the total.

Claim 8

The biconstituent fibers of claim 1 wherein the size is in the denier range of about 0.5 to about 15.

Claim 9

The biconstituent fibers of claim 1 wherein the size is in the denier range of about 1 to about 5.

Claim 10

The blend of claim 1 wherein the LLDPE has a density in the range of about 0.92 to about 0.94 gms/cc.

Claim 11

The blend of claim 1 wherein the LLDPE has a density of about 0.925 gms/cc.

Claim 12

The biconstituent fibers of claim 1 comprising a polypropylene continuous phase of the fibers, and LLDPE dispersed in the polypropylene as a discontinuous phase in the form of fibrils wherein said fibrils are predominantly of a diameter of less than about 0.05 microns.

Claim 13

The biconstituent fibers of claim 1 wherein the tenacity of the fibers is greater than either of the constituents taken alone.

Claim 14

The biconstituent fiber of claim 1 wherein the softness is better than the polypropylene constituent taken alone.

Claim 15

A biconstituent fiber consisting essentially of highly crystalline polypropylene as a continuous phase, having distributed therein 22 to about 45 percent by weight of polyethylene fibrils as a dispersed phase arrayed in a substantially omni-directionally splayed manner, wherein said polyethylene is LLDPE having a melt flow rate in the range of about 20 to about 100 gms/10 min., a density in the range of about 0.92 to about 0.94 gms/cc, and an alkylene comonomer content in the range of about 3 to about 20 percent by weight of the LLDPE, and wherein the biconstituent fiber has a denier size of less than about 30, said biconstituent fiber having been produced in a fiber-making process which uses an intensive mixer-extruder in melt-blending and melt-extruding the polypropylene and LLDPE.

Claim 16

A biconstituent fiber consisting essentially of highly crystalline polypropylene as a continuous phase, having distributed therein 22 to about 45 percent by weight of polyethylene fibrils as a dispersed phase arrayed in a substantially omni-directionally splayed manner, wherein said polyethylene is LLDPE having a melt flow rate in the range of about 20 to about 100 gms/10 min., a density in the range of about 0.92 to about 0.94 gms/cc, and an alkylene comonomer content in the range of about 3 to about 20 percent by weight of the LLDPE, and wherein the biconstituent fiber has a denier size of less than about 30, said biconstituent fiber having been produced in a fiber-making process which uses an intensive mixer-extruder in melt-blending and melt-extruding the polypropylene and LLDPE.

Claim 17

The biconstituent fiber of claim 14 having a denier size in the fine denier range of about 0.5 to about 15.

Claim 18

The biconstituent fiber of claim 14 having a fine denier size in the range of about 1 to about 5.

Claim 19

The biconstituent fiber of claim 14 wherein the LLDPE has a melt flow rate of about 50±20 gms/10 min.

Claim 20

The biconstituent fiber of claim 14 wherein the LLDPE fibrils are predominantly of a diameter of less than about 0.05 microns.

Claim 21

The biconstituent fiber of claim 14 wherein the said alkylene comonomer is 1-octene.