Polyester fiber
An object of the present invention is to improve spinnability, productivity, and tensile strength of a polyester fiber containing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). By spinning the polyester resin containing the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) at a high spinning velocity, the spinnability, productivity, and tensile strength of the polyester fiber can be improved.
1. A polyester fiber produced by spinning a polyester resin comprising poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) at a spinning velocity of from 1,500 to 7,000 m/min,
wherein the polyester fiber has a ratio I β /I α of not less than 0.02, where I α denotes a diffraction intensity from α-crystals, I β denotes a diffraction intensity from β-crystals, and an influence on I α and I β caused by an amorphous phase in the polyester fiber is removed when measuring I α and I β .
2. The polyester fiber according to claim 1 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) comprises 3-hydroxybutyrate as a monomer in an amount of from 99.5 to 88.5 mol %.
3. The polyester fiber according to claim 1 , wherein the spinning of the polyester resin comprises extruding the polyester resin from a spinning die at a resin temperature of from 145 to 190° C.
4. The polyester fiber according to claim 1 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) has a weight-average molecular weight of from 150,000 to 1,500,000.
5. The polyester fiber according to claim 1 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) has a weight-average molecular weight of from 200,000 to 1,000,000.
6. The polyester fiber according to claim 1 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) comprises 3-hydroxybutyrate as a monomer in an amount of from 99 to 93 mol %.
7. The polyester fiber according to claim 1 , wherein the polyester resin comprises not less than 70 wt % of the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).
8. The polyester fiber according to claim 1 , wherein the polyester resin further comprises at least one of a lubricant and a plasticizer.
9. A method for producing a polyester fiber, comprising:
spinning a polyester resin comprising poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) at a spinning velocity of from 1,500 to 7,000 m/min such that a polyester fiber is produced and that the polyester fiber has a ratio I β /I α of not less than 0.02, where I α denotes a diffraction intensity from α-crystals, I β denotes a diffraction intensity from β-crystals, and an influence on I α and I β caused by an amorphous phase in the polyester fiber is removed when measuring I α and I β .
10. The method according to claim 9 , wherein the spinning of the polyester resin comprises extruding the polyester resin from a spinning die at a resin temperature of from 145 to 190° C.
11. The method according to claim 9 , wherein the spinning of the polyester resin comprises extruding the polyester resin from a spinning die at a resin temperature of from 150 to 190° C.
12. The method according to claim 9 , wherein the spinning die has an opening having an area of from 0.15 mm 2 to 3.5 mm 2 .
13. The method according to claim 9 , wherein, in the spinning, the spinning velocity is from 2,000 to 7,000 m/min.
14. The method according to claim 9 , further comprising:
culturing a microorganism such that the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) is accumulated in the microorganism.
15. The method according to claim 9 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) comprises 3-hydroxybutyrate as a monomer in an amount of from 99.5 to 88.5 mol %.
16. The method according to claim 9 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) has a weight-average molecular weight of from 150,000 to 1,500,000.
17. The method according to claim 9 , wherein the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) comprises 3-hydroxybutyrate as a monomer in an amount of from 99 to 93 mol %.
18. The method according to claim 9 , wherein the polyester resin comprises not less than 70 wt % of the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).
19. The method according to claim 9 , wherein the polyester resin further comprises at least one of a lubricant and a plasticizer.
20. The method according to claim 9 , further comprising:
stretching the polyester fiber within 120 minutes after the spinning of the polyester resin is completed.
21. A polyester fiber produced by spinning a polyester resin comprising poly(3-hydroxybutyrate-co-3-hydroxyhexanoate),
wherein the polyester fiber has a ratio I β /I α of not less than 0.02, where I α denotes a diffraction intensity from α-crystals, I β denotes a diffraction intensity from β-crystals, and an influence on I α and I β caused by an amorphous phase in the polyester fiber is removed when measuring I α and I β .
22. The polyester fiber of claim 21 , wherein a spinning velocity is not less than 1,500 m/min.