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US-20260125827-A1 - POLYHYDROXYALKANOATE-BASED FIBERS

US20260125827A1US 20260125827 A1US20260125827 A1US 20260125827A1US-20260125827-A1

Abstract

A synthetic fiber is disclosed, formed from a composition which is made of from about 1 to about 98 weight percent of at least one polyhydroxyalkanoate; from about 1 to about 10 weight percent of at least one nucleating agent selected from the group consisting of polyester waxes, behenamide, crodamide, stearamide, erucamide, pentaerythritol, dipentaerythritol, boron nitride, and mixtures thereof; and from about 0.1 to about 5 weight percent of at least one melt flow modifier selected from the group consisting of calcium stearate, zinc stearate, starch, diamide oligomers, organic peroxides, and mixtures thereof.

Inventors

  • Michael N. Mang
  • Mangaldeep Kundu
  • Karson Durie
  • Adam Johnson

Assignees

  • DANIMER IPCO, LLC

Dates

Publication Date
20260507
Application Date
20240130

Claims (20)

  1. 1 . A synthetic fiber formed from a composition comprising: from 30 to 65 weight percent of at least one polyhydroxyalkanoate; from 30 to 60 weight percent of at least one biopolymer selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, phenylbenzimidazole sulfonic acid, and mixtures thereof; from 1 to 10 weight percent of at least one nucleating agent selected from the group consisting of polyester waxes, behenamide, stearamide, erucamide, pentaerythritol, dipentaerythritol, boron nitride, and mixtures thereof; and from 0.1 to 5 weight percent of at least one melt flow modifier selected from the group consisting of calcium stearate, zinc stearate, starch, diamide oligomers, and mixtures thereof.
  2. 2 . The synthetic fiber of claim 1 , wherein the composition comprises from 1 to 97 weight percent of at least one polyhydroxyalkanoate copolymer or terpolymer and from 1 to 20 weight percent of polyhydroxybutyrate, based on a total weight of the polyhydroxyalkanoate in the composition.
  3. 3 . (canceled)
  4. 4 . The synthetic fiber of claim 1 , wherein the at least one polyhydroxyalkanoate comprises a polyhydroxyalkanoate copolymer.
  5. 5 . The synthetic fiber of claim 1 , wherein the at least one poly(hydroxyalkanoate) comprises from 1 to 25 mole percent monomer repeat units selected from the group consisting of 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof.
  6. 6 . The synthetic fiber of claim 1 , wherein the at least one polyhydroxyalkanoate comprises poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (P3HB-co-P3HHx), comprising from 2 to 8 mole percent monomer repeat units of 3-hydroxyhexanoate.
  7. 7 . The synthetic fiber of claim 1 , wherein the at least one polyhydroxyalkanoate comprises a polyhydroxyalkanoate terpolymer, wherein the terpolymer comprises from 75 to 99.8 mole percent monomer repeat units of 3-hydroxybutyrate, from 0.1 to 24.9 mole percent monomer repeat units of 3-hydroxyhexanoate, and from 0.1 to 24.9 mole percent monomer repeat units of a third 3-hydroxyalkanoate selected from the group consisting of 3-hydroxyhexanoate, 3-hydroxyoctanoate, and 3-hydroxydecanoate.
  8. 8 . The synthetic fiber of claim 1 , wherein the at least one polyhydroxyalkanoate has a weight average molecular weight from 50,000 to 1,500,000 Daltons, as determined by ASTM D5296-05.
  9. 9 . The synthetic fiber of claim 1 , wherein the at least one polyhydroxyalkanoate has a bimodal molecular weight distribution, having a first molecular weight peak centered at 100,000 to 175,000 Daltons and a second molecular weight peak centered at 200,000 to 300,000 Daltons, as determined by ASTM D5296-05.
  10. 10 . (canceled)
  11. 11 . The synthetic fiber of claim 1 , wherein the composition has a melting temperature from 140° C. to 150° C. as determined by ASTM D3418.
  12. 12 . The synthetic fiber of claim 1 , wherein the composition further comprises from 0.1 to 4.0 weight percent of at least one melt strength enhancer selected from the group consisting of carbodiimides, epoxides, and mixtures thereof.
  13. 13 . The synthetic fiber of claim 1 , wherein the fiber is filament spun, and the composition has a melt flow index from 5 to 30 grams/10 minutes when measured at a temperature of 175° C. with a 2.16 kg load in accordance with ASTM D1238.
  14. 14 . The synthetic fiber of claim 1 , wherein the fiber is post-treated with a fiber lubricant composition, which includes at least one lubricant selected from the group consisting of hydrophobic esters, mineral oils, silicon compositions, and mixtures thereof.
  15. 15 . A spunbond nonwoven fabric formed from the synthetic fiber of claim 1 , wherein the composition has a melt flow index from 50 to 100 grams/10 minutes when measured at a temperature of 175° C. with a 2.16 kg load in accordance with ASTM D1238.
  16. 16 . A melt-blown nonwoven fabric formed from the synthetic fiber of claim 1 , wherein the composition has a melt flow index from 500 to 1500 grams/10 minutes when measured at a temperature of 175° C. with a 2.16 kg load in accordance with ASTM D1238.
  17. 17 . A method for forming a plurality of synthetic fibers, comprising steps of: blending at least one polyhydroxyalkanoate, at least one nucleating agent, and at least one melt flow modifier in a first extruder to form a resin composition, wherein the resin composition comprises from 30 to 65 weight percent of at least one polyhydroxyalkanoate; from 30 to 60 weight percent of at least one biopolymer selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, phenylbenzimidazole sulfonic acid, and mixtures thereof; from 1 to 10 weight percent of at least one nucleating agent selected from the group consisting of polyester waxes, behenamide, stearamide, erucamide, pentaerythritol, dipentaerythritol, boron nitride, and mixtures thereof; and from 0.1 to 5 weight percent of at least one melt flow modifier selected from the group consisting of calcium stearate, zinc stearate, starch, diamide oligomers, and mixtures thereof; and melt processing the resin composition at a temperature from 165 to 185° C. and extruding the composition through a plurality of spinnerets to produce a plurality of fibers.
  18. 18 . The method of claim 17 , wherein the plurality of fibers comprise fiber filaments having a length of at least 300 mm, and wherein the resin composition has a melt flow index from 5 to 30 grams/10 minutes when measured at a temperature of 175° C. with a 2.16 kg load in accordance with ASTM D1238.
  19. 19 . (canceled)
  20. 20 . The method of claim 17 , further comprising collecting the plurality of fibers on a flat conveyer belt and bonding the fibers together to form a spunbond nonwoven web.

Description

FIELD This disclosure relates, in general, to synthetic fibers. More particularly, this disclosure relates to synthetic fibers made from polyhydroxyalkanoates combined with a second biopolymer. BACKGROUND Synthetic fibers are traditionally formed from petroleum-based polymers such as polypropylene or polyethylene terephthalate. Despite the good mechanical properties of these polymers, there is a growing demand for fibers formed from more environmentally friendly materials, such as polyhydroxyalkanoates (PHAs). However, PHA fibers have been found to be challenging to work on due to poor mechanical strength and/or thermal degradability compared to petroleum-based polymers. Thus, it would be desirable, and an object of the present disclosure, to provide synthetic fibers formed from PHA-based compositions having improved mechanical properties and resistance to thermal degradation. Preferably, the fibers formed from these PHA-based compositions would have mechanical properties comparable to those of fibers formed from petroleum-based polymers. It would also be desirable, and an object of the present disclosure, to provide methods for forming synthetic fibers from PHA-based compositions which preserve the molecular weight and mechanical properties of the PHA-based compositions. SUMMARY The above and other needs are met by synthetic fibers formed from PHA-based compositions, according to the present disclosure. In one aspect, the present disclosure provides a synthetic fiber. According to certain embodiments, the synthetic fiber is formed from a composition that is made of from about 1 to about 98 weight percent of at least one polyhydroxyalkanoate. The composition is also made of from about 1 at about 10 weight percent of at least one nucleating agent selected from the group consisting of polyester waxes, behenamide, crodamide, stearamide, erucamide, pentaerythritol, dipentaerythritol, boron nitride, and mixtures thereof and from about 0.1 at about 5 weight percent of at least one melt flow modifier selected from the group consisting of calcium stearate, zinc stearate, starch, diamide oligomers, organic peroxides and mixtures thereof and mixtures thereof. Preferably, the composition is made of from about 30 to about 70 weight percent of the at least one polyhydroxyalkanoate, from about 1 to about 5 weight percent of the at least one nucleating agent, and from about 0.1 to about 3 weight percent of the at least one melt flow modifier. Still, more preferably, the composition is made of from about 40 to about 60 weight percent of the at least one polyhydroxyalkanoate, from about 1.5 to about 3 weight percent of the at least one nucleating agent, and from about 0.2 to about 3 weight percent of the at least one melt flow modifier. In some embodiments, the composition may include a mixture of different polyhydroxyalkanoates. In some embodiments, for example, the composition may be made up of from about 1 to about 97 weight percent of at least one polyhydroxyalkanoate copolymer or terpolymer and from 1 to about 20 weight percent of polyhydroxybutyrate. Preferably, the composition is made up of from about 30 to about 70 the at least one polyhydroxyalkanoate copolymer or terpolymer, and from 5 to about 15 weight percent of the polyhydroxybutyrate. Still more preferably, the composition is made up of from about 40 to about 60 the at least one polyhydroxyalkanoate copolymer or terpolymer, and from 7 to about 12 weight percent of the polyhydroxybutyrate. In certain embodiments, other biodegradable polymer may be included, along with polyhydroxyalkanoates. For instance, the composition may include from about 30 to about 65 weight percent of at least one polyhydroxyalkanoate and from about 30 to about 60 weight percent of at least one biopolymer selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, phenylbenzimidazole sulfonic acid, and mixtures thereof. Preferably, the composition may include from about 35 to about 60 weight percent of the at least one polyhydroxyalkanoate and from about 30 to about 50 of the at least one biopolymer. Still, more preferably, the composition may include from about 40 to about 56 weight percent of the at least one polyhydroxyalkanoate and from about 30 to about 40 weight percent of the at least one biopolymer. In some embodiments, the at least one polyhydroxyalkanoate is made up of polyhydroxyalkanoate copolymer. According to certain embodiments, the at least one poly(hydroxyalkanoate) is made of from about 5 to about 20 mole percent monomer repeat units selected from the group consisting of 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, and mixtures thereof. Still, more preferably, the at least one poly(hydroxyalkanoate) is made of from about 10 to about 15 mole percent monomer repeat units. In some instances, the at least one polyhydroxyalkanoate is made up of poly-3-hydroxybutyrate-co-3-h