Ultrafine polyactic acid fibers and fiber structure, and process for their production

a technology of polylactic acid fibers and fibers, applied in the field of fibers, can solve the problems of large environmental load, poor heat resistance of ultrafine fibers referred to above, and limited use, and achieve excellent heat resistance and biodegradability, and small fiber diameter

Inactive Publication Date: 2007-07-26
TEIJIN LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0014] It is an object of the present invention to overcome the aforementioned problems of the prior art by providing fibers with a very small fiber diameter, and excellent heat resistance and biodegradability.

Problems solved by technology

Yet because 6-nylon, polyethylene terephthalate, polypropylene and the like used for conventional ultrafine fibers do not decompose in soil or compost, they must be incinerated or buried after use and therefore create a major environmental load due to atmospheric pollution or prolonged durability after burial.
However, the ultrafine fibers referred to above have poor heat resistance and their uses have therefore been limited.
However, hitherto obtained polylactic acid stereo complex fibers are mixtures of poly(L-lactic acid) single crystals and poly(D-lactic acid) single crystals, and their heat resistance has been insufficient.
Such fibers have large fiber diameters and the fiber structures formed from the fibers have exhibited inadequate flexibility (for example, see Patent documents 3 and 4).

Method used

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  • Ultrafine polyactic acid fibers and fiber structure, and process for their production
  • Ultrafine polyactic acid fibers and fiber structure, and process for their production
  • Ultrafine polyactic acid fibers and fiber structure, and process for their production

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0089] After mixing 500 pp m of tin octylate with D-lactide, polymerization was conducted in a stirrer-equipped reactor at 200° C. for 60 minutes under a nitrogen atmosphere, to obtain a poly(D-lactic acid) homopolymer with a weight-average molecular weight of 120,000.

[0090] There were prepared a solution of 1 part by weight of the obtained poly(D-lactic acid) in 9 parts by weight of methylene chloride and a solution of 1 part by weight of poly(L-lactic acid) (Lacty 9031™ by Shimadzu Corp., weight-average molecular weight: 168,000) in 9 parts by weight of methylene chloride, and both solutions were mixed at 5 parts by weight each.

[0091] Next, the apparatus shown in FIG. 2 was used for discharge of the solution for 5 minutes onto a filamentous substance-collecting electrode 5. The inner diameter of the ejection nozzle (1 in FIG. 2) was 0.8 mm, the voltage was 12 kV, the distance from the ejection nozzle (1 in FIG. 2) to the filamentous substance-collecting electrode (5 in FIG. 2) w...

example 2

[0093] There were mixed 6 parts by weight of a solution of 1 part by weight of the poly(D-lactic acid) in 9 parts by weight of methylene chloride and 4 parts by weight of a solution of 1 part by weight of poly(L-lactic acid) in 9 parts by weight of methylene chloride, and a fiber structure was obtained in the same manner as Example 1, except that the distance from the ejection nozzle to the filamentous substance-collecting electrode was 10 cm.

[0094] The mean fiber diameter of the obtained fiber structure was 4 μm, and no fibers were present with fiber lengths of less than 20 μm. The mean diameter of the depressions on the fiber surfaces was 0.2 μm, and the percentage of the fiber surface area occupied by the depressions was 22%. Scanning electron microscope photographs of the fiber structure are shown in FIGS. 5 and 6.

[0095] As a result of DSC measurement of the obtained fiber structure, the melting point was 218° C. and no endothermic peak was observed below 190° C.

example 3

[0105] A fiber structure was obtained in the same manner as Example 2, except that a methylene chloride / DMF mixed solvent (weight ratio: 8 / 2) was used instead of methylene chloride. The mean fiber diameter of the obtained fiber structure was 2 μm, and no fibers were present with fiber lengths of less than 20 μm. No fiber surface depressions were observed. Scanning electron microscope photographs of the fiber structure are shown in FIGS. 13 and 14.

[0106] As a result of DSC measurement of the obtained fiber structure, the melting point was 220° C. and no endothermic peak was observed below 190° C.

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Abstract

A fiber structure is obtained by spinning of a solution of an L-lactic acid condensate and a D-lactic acid condensate by electrospinning. It is possible to provide a fiber structure comprising fibers with extremely small fiber diameters, as well as excellent heat resistance and biodegradability.

Description

TECHNICAL FIELD [0001] The present invention relates to fibers comprising biodegradable polylactic acid as a constituent component, and more specifically it relates to ultrafine polylactic acid fibers and a fiber structure, and to a process for their production. BACKGROUND ART [0002] Ultrafine fibers have a soft feel and are therefore used for such purposes as woven and knitted fabrics or artificial leather, for clothing or interior goods. [0003] They are also used in the forms of sheets or nonwoven fabrics for such purposes as filters, insulating sheets, wipers, packing materials, sanitary goods and the like. [0004] In recent years it has been desirable to reduce environmental load from the standpoint of preserving the earth environment. Yet because 6-nylon, polyethylene terephthalate, polypropylene and the like used for conventional ultrafine fibers do not decompose in soil or compost, they must be incinerated or buried after use and therefore create a major environmental load due...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): D02G3/00D01D5/00D01D5/04D01F6/62D01F6/84D01F6/92D04H1/728
CPCD01D5/0038Y10T428/2929D01F6/84D01F6/625D01F6/62D04H1/435D01D5/00D04H1/56
Inventor MIYOSHI, TAKANORITOYOHARA, KIYOTSUNAMINEMATSU, HIROYOSHI
Owner TEIJIN LTD
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