# US 12,006,593 B2 · Method of manufacture of curly fibers

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- Number: US 12,006,593 B2
- Document ID: US12006593B2
- Status: Granted
- Kind: B2
- Application number: 17/295,070
- Filed: 2019-11-20
- Published: 2022-07-21
- Granted: 2024-06-11
- Earliest claimed: 2018-11-20
- Assignees: Dow Global Technologies LLC
- Applicants: Dow Global Technologies LLC
- Inventors: Akanksha Garg; Yinglong Chen; Yijian Lin; Sanjib Biswas; Pavan Kumar Valavala; Fabricio Arteaga Larios; Jill Martin
- Web page: https://patentgrep.com/patent/US12006593B2

## CPC

- D01D 5/22: with a crimped or curled structure; with a special structure to simulate wool (producing crimped or curled effects in filaments or threads after formation D02G1/00)
- D01D 5/30: Conjugate filaments; Spinnerette packs therefor
- D01F 8/06: with at least one polyolefin as constituent
- D04H 1/4291: Olefin series
- D04H 1/435: Polyesters
- D04H 1/43835: {Mixed fibres, e.g. at least two chemically different fibres or fibre blends}
- D10B 2321/022: polypropylene
- D10B 2331/04: polyesters, e.g. polyethylene terephthalate [PET]
- D10B 2401/06: Load-responsive characteristics
- D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B)
- D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES

## Abstract

A process comprising forming fibers having at least a first region and a second region wherein the first region comprises an ethylene/alpha olefin interpolymer composition characterized by: density in the range of 0.930 to 0.965 g/cm3; melt index (I2) in the range of from 10 to 60 g/10 minutes; molecular weight distribution in the range of from 1.5 to 2.6; tan delta at 1 radian/second of at least 45; a low temperature peak and a high temperature peak on an elution profile via improved comonomer composition distribution (ICCD) procedure; and full width at half maximum of the high temperature peak is less than 6.0° C. and stretching the fibers to an elongation of at least 20% thereby increasing curl of the fiber. The process may further include forming a non-woven from the fibers and the stretching of the fibers may occur before or after forming of the non-woven.

## Claims

### Claim 1

A process comprising
forming fibers each having at least a first region and a second region wherein the first region comprises an ethyl ene/alpha olefin interpolymer composition characterized by a density in the range of 0.930 to 0.965 g/cm3, a melt index (12) in the range of from 10 to 60 g/10 minutes, wherein the 12 is measured according to ASTM D1238, 190C, 2.16 kg, a molecular weight distribution, expressed as the ratio of the weight average molecular weight to number average molecular weight (MW(GPC)/Mn(GPC)) as determined by GPC in the range of from 1.5 to 2.6, a tan delta at 1 radian/second of at least 45, a low temperature peak and a high temperature peak on an elution profile via improved comonomer composition distribution (ICCD) procedure, and a full width at half maximum of the high temperature peak is less than 6.0° C. stretching the fibers to an elongation of at least 20% thereby increasing curl of the fiber.

### Claim 2 (depends on 1)

The process of claim 1 wherein the ethylene/alpha olefin interpolymer composition is further characterized by one or more of the following: the density is in the range of 0.930 to 0.940 g/cm3, the ethylene/alpha-olefm interpolymer composition has a peak temperature of the low temperature peak in a range of 60 to 80° C. a weight fraction of the low temperature peak of 25 to 65%, a peak temperature of the high temperature peak of greater than 90° C., and a weight fraction of the high temperature peak of 35 to 75%.

### Claim 3 (depends on 1)

The process of claim 1 wherein the first region has a first 2% secant modulus, E1, and a first yield stress, σy1, and the second region has a second 2% secant modulus, E2, a second yield stress, σy2 and the first 2% secant modulus, E1, is different from the second 2% secant modulus, E2, or the first yield strength, σy1, is different from the second yield strength, σy2, or both.

### Claim 4 (depends on 3)

The process of claim 3 wherein a difference in the yield stress of the materials of the first and second regions divided by the yield stress of the second region is at least 0.4.

### Claim 5 (depends on 3)

The process of claim 3 wherein a difference in the 2% secant modulus of the materials of the first and second regions divided by the 2% secant modulus of the second region is at least 0.4.

### Claim 6 (depends on 3)

The process according to claim 3 wherein |σy1/E1-σy2/E2|/(σy2/E2), is at least 0.01.

### Claim 7 (depends on 1)

The process of claim 1 wherein the second region comprises a polyolefin different from the ethylene/alpha olefin interpolymer composition of the first region or a polyester.

### Claim 8 (depends on 7)

The process of claim 7 wherein the second region comprises a polypropylene.

### Claim 9 (depends on 8)

The process of claim 8 wherein the first region is a sheath around a core of the second region or the second region is a sheath around a core of the first region.

### Claim 10 (depends on 8)

The process of claim 8 wherein the stretching occurs at a temperature which is in the range of 5 to 90° C.

### Claim 11 (depends on 8)

The process of claim 8 wherein the fibers are formed into a non-woven web.

### Claim 12 (depends on 11)

The process of claim 11 wherein the stretching occurs after forming the non-woven web.

### Claim 13 (depends on 1)

The process of claim 1 wherein the first region is a sheath around a core of the second region or the second region is a sheath around a core of the first region.

### Claim 14 (depends on 1)

The process of claim 1 further comprising heating the fibers before or after stretching.

### Claim 15 (depends on 1)

The process of claim 1 wherein the stretching occurs at a temperature which is in the range of 5 to 90° C.

### Claim 16 (depends on 1)

The process of claim 1 wherein the fibers are formed into a non-woven web.

### Claim 17 (depends on 16)

The process of claim 16 wherein the stretching occurs after forming the non-woven web.

### Claim 18 (depends on 16)

The method of claim 16 wherein the loft of the non-woven increases after stretching by at least 10%.