JPH05279911A - Production of special hollow fiber and fiber bulk material therefrom - Google Patents

Abstract

(57) [Summary] [Object] To provide a hollow fiber suitable for obtaining a fiber product that is lightweight and has a good balance between heat retention and water absorption and excellent anti-pill property. [Structure] A hollow fiber in which a void portion communicating the hollow portion and the fiber surface exists continuously in the fiber axial direction, and the minimum width of the void portion is 4.5√Dr (Dr is the hollow fiber Hollow fiber having a single fiber fineness of not more than μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber having a good balance between heat retention and water absorption and excellent anti-pill property, and a method for producing a fiber product comprising the fiber.

[0002]

2. Description of the Related Art Polyester fibers have been widely used for clothing, production, interior use and the like. However, there is a problem that pilling occurs depending on the application due to the inherent high strength of polyester, which has the drawback of impairing the appearance. Therefore, many proposals have been made regarding the anti-pill technology of polyester fibers, for example, Japanese Patent Laid-Open No. 50-13533.
As disclosed in JP-A-1 and JP-A-61-47818, a polyester having a phosphate ester bond introduced therein is made into a fiber and then hydrothermally treated to hydrolyze the phosphate ester bond to form a fiber. The strength is reduced to impart anti-pill property, or the polyester fiber to which a phosphorus compound is added or copolymerized as disclosed in Japanese Patent Publication No. 58-18447 is heat treated to lower the fiber strength and improve the anti-pill property. Measures such as measuring are made. On the other hand, it has been proposed to make the fiber cross-section hollow as a method of imparting heat retention to the polyester fiber, but when conventional hollow fibers are used, the fibers are subjected to various external forces in the process of reaching the final fiber product. At the stage of making a fiber product, the hollow part is crushed and the heat retaining property is reduced, and it is not possible to expect sufficient water absorption in the fiber product having such a structure. Thus, conventionally,
It is difficult to produce a fiber having a good balance between heat retention and water absorption, and in the present situation, a fiber having excellent pill resistance has not been obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hollow fiber suitable for obtaining a fiber product which is lightweight and has a good balance between heat retention and water absorption and which has an excellent anti-pill property. is there.

[0004]

That is, the present invention is a hollow fiber characterized in that a gap portion communicating the hollow portion and the fiber outer peripheral surface is preferably continuous in the axial direction of the fiber, A fiber assembly composed of such hollow fibers is composed of two thermoplastic polymers having different dissolution rates or decomposition rates,
A fiber assembly comprising a core-sheath type composite fiber in which a polymer having a slower dissolution rate or a lower decomposition rate constitutes a sheath component, and the sheath component has a void portion communicating from the fiber surface in the core component direction. It is produced by subjecting the body to a treatment for dissolving or decomposing and removing substantially only the polymer constituting the core component of the conjugate fiber.

The hollow fiber of the present invention has a void portion that communicates the hollow portion with the fiber surface, and is, for example, a fiber having a cross section as shown in FIG. The presence of the minute gaps provides well-balanced heat retention and water absorption. Conventional hollow fibers with no gaps have good heat retention but are poor in water absorption. On the other hand, when the width of the gap is too wide, it becomes like a conventional U-shaped cross-section fiber and heat retention is improved. Inferiorly, the water absorption also decreases in a cross section having a wide opening, which is not preferable. Therefore, the minimum width of the gap is 4.5√Dr (Dr is the single fiber fineness of the hollow fiber) μ
It is preferably m or less, and particularly preferably 3.0√Dr μm or less. Further, in order to develop a better water absorption property, it is desirable that the gaps are continuous in the fiber direction. The term "continuous" as used herein means that the distance is 5 mm or more, particularly preferably 1 cm or more. The gap may be present at two or more places in the cross section of the fiber when the cross section of the fiber is arbitrarily observed, but it is preferably at one place in view of the morphological stability of the fiber. The hollow ratio of the hollow fiber of the present invention is preferably 15 to 70%, and if it is less than 15%, the anti-pill property, heat retaining property and water absorption may not be sufficiently exhibited, while if it exceeds 70%, Although the pill property, heat retention and water absorption are increased, the fiber strength becomes too low to cause a problem, and the hollow portion is apt to be punctured, which is not preferable. Therefore, the hollow ratio is especially 20 to 60.
% Is preferable. Further, the hollow fiber of the present invention,
Various single fiber fineness can be obtained depending on the use, but it is preferably about 0.5 to 3 denier. Further, the fiber cross section may be a flat cross section or a polygonal cross section in addition to the round cross section.

The method for producing the hollow fiber of the present invention is not limited as long as it has the above-mentioned structure, but in order to surely form a gap for communicating the hollow portion and the fiber surface, As shown in FIG. 2, it is desirable to use a spinneret that does not completely surround the core component discharge holes as shown in FIG. The size of this gap is not particularly limited as long as it can achieve the object of the present invention. For example, the center point of the spinneret is set to O in FIG. When the two points corresponding to the outer circumference are X and Y, and the angle formed by XOY is the opening angle α, α may be a die having a gap of about 10 to 40 °, preferably about 15 to 35 °. desirable. The gap portion may be parallel [FIG. 2 (A)] from the outer periphery of the die to the inside, may be narrow [FIG. 2 (B)], or may be widened. May be If a spinneret having an opening angle α of less than 10 ° is used, the sheath component is likely to adhere during spinning, and it becomes difficult for the alkali compound to enter the core during alkali reduction treatment, making it difficult to obtain a hollow fiber having a desired shape. On the other hand, if the opening angle α is too wide, the morphological stability of the fiber after alkali treatment is poor and the fiber does not have a clean hollow cross-section, and it also causes a significant decrease in heat retention.

The fiber assembly comprising the hollow fiber of the present invention is
Two kinds of thermoplastic polymers having different dissolution rates or decomposition rates are placed on the sheath component by using the above-mentioned spinneret, and the polymer having the slower dissolution rate or decomposition rate is placed in the sheath component. A polymer is placed in a core component, and a core-sheath type composite fiber is spun according to a conventional method, a fiber assembly is formed using the obtained composite fiber, and the composite fiber of the composite fiber is substantially added to the fiber assembly. It can be produced by subjecting only the polymer constituting the core component to a treatment for dissolving or decomposing and removing it, and in the fiber assembly thus obtained, the hollow portions of the individual fibers exist without being crushed. Therefore, it is possible to exhibit extremely good heat retention. Incidentally, in the present invention, the fiber assembly, a woven fabric containing the hollow fiber of the present invention,
It refers to knitted fabrics, non-woven fabrics, and composites thereof.

In the present invention, as a combination of the above-mentioned thermoplastic polymers, for example, polyester having ethylene terephthalate units or butylene terephthalate units as a sheath component as a main component can be mentioned, and polyethylene terephthalate is particularly preferable. Examples of the core component include the polyester modified with a third component such as isophthalic acid, 5 alkali metal sulfoisophthalic acid (hereinafter abbreviated as SIP), polyalkylene glycol and the like. Particularly, a polyester copolymerized with SIP is preferably used as the core component. In this case, the SIP copolymerization rate is preferably 2.5 to 7.5 mol%, and more preferably 4.5 to 5.5 mol%. Or 100 parts by weight of this copolyester has a molecular weight of
0 to 20,000 polyalkylene glycol 0.3 to
Polymers containing 3 parts by weight are also preferably used. The reason for such a modification rate is that if the SIP content is less than 2.5 mol%, the core component cannot be sufficiently removed in the subsequent alkali treatment for forming the hollow portion, and the target hollow fiber form is formed. This is because it is difficult, and when it exceeds 7.5 mol%, the thickening effect at the time of melting becomes large, so that it becomes difficult to form a composite fiber at the time of spinning, and the molecular weight of the polyalkylene glycol is 10 or less.
If it is less than 00, the compatibility with the polyester is improved and the shape of the sheath component to be left when the alkali is reduced may be impaired. On the other hand, when the molecular weight exceeds 20,000, the heat resistance and light resistance of the polyalkylene glycol itself are deteriorated, which is not preferable. If the amount of polyalkylene glycol added is less than 0.3% by weight, it does not play a role of accelerating the weight reduction rate when reducing the alkali. 3% by weight
If it exceeds, light resistance deteriorates, which is not desirable. Although it is a portion to be reduced and removed later, if a portion remains, the appearance of the product may be impaired, which is not preferable.

The SIP is, for example, 3,5-
Sodium (or potassium or lithium) di (carbomethoxy) benzenesulfonate, 3,5-di (β
-Hydroxyethoxycarbonyl) benzenesulfonate sodium (or potassium or lithium), 3,
5-di (β-hydroxybutoxycarbonyl) benzenesulfonate sodium (or potassium or lithium) and the like can be mentioned. In order to produce a copolyester in which such SIP is copolymerized, SIP may be added to the reaction system at any stage before the completion of polyester synthesis.

The above-mentioned polyalkylene glycol is used when it is necessary to improve the fluidity depending on the amount of SIP added, and is not particularly limited, and examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol. Etc. and two or more of these random or block copolymers can be used. These may be copolymerized with polyester or may have a copolymerizability lost by end-capping. Furthermore, a hindered phenol-based antioxidant, a phosphite-based antioxidant or the like may be used in combination with the polyalkylene glycol. In that case, the method of adding the polyalkylene glycol and the antioxidant may be at any stage from the start of polyester synthesis to the time of spinning, but considering thermal decomposition, it is preferable to add them at a step close to spinning, particularly from an extruder at spinning. It is preferable to add in the line leading to the spinning head.

The ratio of the core component to the sheath component in the composite fiber is 5/95 to 50/50, preferably 10/90 to 30 /.
70 is good. Outside this range, the core /
It is difficult to adjust the sheath ratio, and the process passability decreases even in the stretching process. In the present invention, the method for removing the core component may be carried out by dissolution or decomposition. When the SIP modified polyester as described above is used as the core component, the hollow fiber is formed by treating the composite fiber with an aqueous solution of an alkali compound. can do. Alkali treatment can be performed at any stage after spinning, but after spinning, the fiber undergoes various external forces before the fiber product is deformed and its cross section is deformed. In order to achieve the above, it is preferable that the alkali treatment is carried out as a post process. As a result, the heat retention and water absorption of the cloth and the like can be made extremely higher than those of conventional hollow fibers. Particularly in the present invention, it is preferable to add a hydrophilizing agent in an amount of about 0.1 to 2% by weight in order to further improve water absorption. Examples of the hydrophilizing agent include permalose and SR-1000.
Etc. can be used.

As the alkali compound used for the alkali treatment, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate and the like can be used. Of these, sodium hydroxide and potassium hydroxide are particularly preferable. In addition, an alkali weight loss accelerator such as an alkyl quaternary ammonium salt may be appropriately used. The aqueous solution concentration of the alkali compound varies depending on the kind of the alkali compound, the treatment method and the like, but is usually 0.01 to 40% by weight, and particularly preferably 0.1 to 30% by weight. The processing temperature ranges from room temperature to 160 ° C, and the processing time is 30 seconds to
It may be carried out within a range of 4 hours. The alkali reduction treatment step may be performed independently as a single step, or may be performed in combination with other steps. In the latter case, for example, the dye washing and the alkali treatment can be simultaneously performed in the reduction washing step or soaping step after dyeing with the disperse dye or the cationic dye.

The hollow fiber of the present invention obtained in this manner exists in the final fiber product without crushing the hollow portion, so that high heat retention and water absorption can be developed in a well-balanced manner and high resistance can be obtained. It has a pill property and is very suitable for various clothing fabrics using short fibers. Also,
It can be used in the field of long fibers and other fields of short fibers where heat retention and water absorption are required, and is suitable as a material for various fillings such as futon.

[0014]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.

Example 1 120 parts per 100 parts by weight of a melt of copolymerized polyethylene terephthalate ([η] = 0.45) containing 5-sodium sulfoisophthalic acid in a proportion of 3 mol% based on the acid component.
After adding 2 parts by weight of polyethylene glycol having a molecular weight of 10,000 and heated at 0 ° C., and stirring and mixing, it was extruded into water to prepare raw material chips. Then, using the die shown in FIG. 2 (A) (opening angle α = 25 °), the raw material chip was used as a core component, while polyethylene terephthalate having an [η] of 0.65 was used as a sheath component, and a known composite Spinning temperature 285 ° C., discharge rate 350 g / min, core-sheath ratio 50:50,
An undrawn yarn was obtained at a winding speed of 1100 m / min. After this is bundled, it is stretched at a draw ratio of 2.5 times, and after crimp heat treatment, 5
It was cut into 1 mm to obtain 2.5 denier core-sheath type composite fibers.
A spun yarn of 40 / 2S was prepared according to a conventional method using 100% of this short fiber, and the spun yarn was used as a warp and a weft to prepare a plain woven fabric (weight per unit area: 300 g / m ↑ 2). Then 30
The woven fabric was dipped in a sodium hydroxide aqueous solution of g / liter and treated with alkali at 95 ° C. to obtain a fabric having a weight loss rate of 50%. When the woven fabric after the treatment is observed under a microscope, the core component of the composite fiber is cleanly removed, and there is a gap that connects the hollow portion and the fiber surface, and the minimum width of the gap is about 1 on average. It was 0.1 μm. Further, the hollow portion was not crushed at all, and a gap portion was continuously present on the fiber surface along the fiber axis. The strength of the treated fiber was 4.0 g.
Regarding the woven fabric obtained here, JISL-1076-1
Pilling test by A method of 978, JISL-109
6-1990, 6.26.1 B method (Bayrec method) water absorption and JIS L-1079-1976 heat retention were evaluated. The results are shown in Table 1. In the measurement of water absorption, SR-1000 was used as a measurement sample.
(Made by Takamatsu Yushi Co., Ltd.) with 0.5% adhered was used.

[0016]

[Table 1]

Examples 2 and 3 SIP copolymerization rate, amount of polyethylene glycol added,
Fiberizing was performed in the same manner as in Example 1 except that the core-sheath ratio, the opening angle of the spinneret and the single fiber fineness were changed as shown in Table 1, and a woven fabric was produced in the same manner as in Example 1, and various properties thereof were obtained. Was evaluated. The results are shown in Table 1.

COMPARATIVE EXAMPLE 1 Polyethylene terephthalate was used, the single fiber fineness was 3.5 denier, and the spacing between the openings in the fiber cross section was 12.
A woven fabric was prepared in the same manner as in Example 1 by using U-shaped cross-section fibers of μm, and various properties such as pilling property, heat retention property and water absorption property were evaluated. The results are shown in Table 1.

Comparative Example 2 Polyethylene terephthalate having a hollow ratio of 23
%, A single fiber fineness of 5 denier and a conventional hollow fiber having no gaps as in the present invention was used to prepare a woven fabric in the same manner as in Example 1, and the pilling property, heat retention property, water absorption property, etc. evaluated. The results are shown in Table 1.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a cross section of a hollow fiber of the present invention.

FIG. 2 is a diagram illustrating a cross section of a die for producing the hollow fiber of the present invention.

[Explanation of symbols]

 1 gap part 2 hollow part 3 minimum width of gap part 4 mouthpiece part for forming a gap part in fiber cross section 5 part discharged by sheath component 6 part discharged by core component

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Claims (5)

[Claims] 1. A hollow fiber, characterized in that there is a gap that connects the hollow portion and the fiber surface. 2. The hollow fiber according to claim 1, wherein the gap portion is continuously present in the fiber axis direction. 3. The hollow fiber according to claim 1, wherein the minimum width of the gap is 4.5√Dr (Dr is the single fiber fineness of the hollow fiber) μm or less. 4. A core-sheath type composite fiber comprising two kinds of thermoplastic polymers having different dissolution rates or decomposition rates, and the polymer having a slower dissolution rate or decomposition rate constitutes a sheath component. The fiber aggregate composed of the composite fiber having a gap communicating from the fiber surface in the core component direction is subjected to a treatment for dissolving or decomposing and removing substantially only the polymer constituting the core component of the composite fiber. The method for producing a fiber assembly comprising the hollow fiber according to any one of claims 1 to 3. 5. The manufacturing method according to claim 4, wherein the gaps are continuously present in the fiber axis direction.