JP2002061024A - Crimped porous hollow fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crimped porous hollow fiber giving a soft touch feeling and good bulkiness to fabrics, and less in the collapse or breakage of the hollow parts and less in a loss of bulkiness during texturing processes or as a textile product. SOLUTION: This crimped porous hollow fiber consists of a polytrimethylene terephthalate polyester, being such that the cross section has at least two hollows and crimps are imparted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention is suitable for use in carpets, high piles, blankets, moquettes, woven or knitted fabrics for clothing, cotton filling, etc., and has a soft feel, excellent bulkiness and excellent bulk recovery. The present invention also relates to a crimped porous hollow fiber which is difficult to fibrillate.

[0002]

2. Description of the Related Art Polyester fibers, especially polyethylene terephthalate fibers, are excellent in mechanical strength, chemical resistance, heat resistance, etc., and are widely used in applications such as carpets, high piles, blankets, moquettes, woven and knitted fabrics for clothing, and cotton wadding. Used.

In such applications, many studies have been made to impart bulkiness to polyethylene terephthalate fibers. JP-A-55-142710, JP-A-62-20609 and the like propose that the bulkiness can be improved by using a porous hollow fiber.

[0004] However, although the above-mentioned porous hollow fiber is certainly improved in terms of bulkiness, not only the hollow is crushed by external force in the process of processing into a non-woven fabric, a cotton filling or a fabric, but also the hollow is broken and the fibril is broken. Problem. Further, when this porous hollow fiber is used for a certain period of time as a fiber product such as carpet, cotton filling, clothing, etc., as described above, the hollow of the fiber is crushed or the fiber is fibrillated to greatly reduce the bulk. However, there is a problem that the quality of such fiber products is reduced.

[0005] On the other hand, there is a demand for making the texture of such porous hollow fibers softer.

[0006]

SUMMARY OF THE INVENTION The present invention has been made on the background of the prior art, and its object is to provide a soft texture, a good bulkiness, and a fiber processing or product quality. It is an object of the present invention to provide a crimped porous hollow fiber which is less crushed or broken when used as a hollow fiber and has extremely little bulk set.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies and found that the above-mentioned object is made of a polytrimethylene terephthalate-based polyester, has a cross section of two or more hollow fibers, and has a crimp. The present inventors have found that this can be achieved by a crimped porous hollow fiber characterized by being imparted, and have reached the present invention.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polytrimethylene terephthalate-based polyester referred to in the present invention is a polyester having a main repeating unit of trimethylene terephthalate. The third component may be copolymerized in an amount of 15 mol% or less, preferably 5 mol% or less based on the weight of the third component.
Examples of preferably used copolymer components include acid components such as isophthalic acid, succinic acid, adipic acid, 2,6-naphthalenedicarboxylic acid, and metal sulfoisophthalic acid such as 5-sodium-sulfoisophthalic acid; 4
-Glycol components such as butanediol, 1,6 hexanediol, cyclohexanediol, and cyclohexanedimethanol.

The intrinsic viscosity of the above polyester is as follows:
0.35 to 1.20 is preferable from the viewpoint of the spinning property and the like.

If necessary, various additives such as a matting agent, a heat stabilizer, a defoaming agent, a coloring agent, a flame retardant, an antioxidant, an ultraviolet absorber, and a fluorescent enhancer may be added to the polyester. A whitening agent, a coloring pigment, and the like may be added.

In the present invention, the fiber of the present invention is made of the above-mentioned polytrimethylene terephthalate-based polyester, has a cross section of two or more hollow fibers, and is provided with crimped pores. It is important that the fibers are hollow fibers, which not only improves the bulkiness and heat retention, but also causes the fibers to be crushed or broken when processed into nonwoven fabrics or cotton fillings or when used as products. Can be reduced, and bulk set can be remarkably improved.

In the present invention, the cross section of a fiber having two or more hollows is defined, for example, by A to L in FIGS.
And a fiber having such a cross section can be obtained from a spinneret having nozzle cross-sectional shapes of A to L shown in FIGS. 1 and 2, respectively.

A fiber having a fiber cross section as described above is
When molded with polyethylene terephthalate, there is a problem that the hollow is crushed or broken and fibrillated, but when such a fiber is molded with polytrimethylene terephthalate-based polyester, the above-mentioned problem hardly occurs and the bulk settling property is remarkably reduced. It can be improved.

Further, the fiber of the present invention needs to be crimped, whereby the bulkiness can be improved.

In the present invention, it is more preferable that the crimp is a spiral three-dimensional crimp and / or a sine curve crimp.
The bulkiness can be improved, and the crimping performance does not decrease even if it is left in a bale shape by applying a strong compression pressure for packing etc., and the card passing property such as spinning, non-woven fabric processing, and cotton filling processing is improved. It can be further improved.

[0016] The fiber having the above-mentioned spiral three-dimensional crimp, when melt-spinning a polytrimethylene terephthalate polymer, blows a cooling air stream onto the yarn immediately after being discharged from the die surface to form a fiber. An undrawn yarn having a high degree of cross-sectional anisotropy in the degree of refraction is drawn, then the yarn is drawn, cut into short fibers, and subjected to a relaxation heat treatment in a state where the restraint between the fibers is reduced, thereby forming a spiral shape. It is obtained by expressing a three-dimensional crimp.

Further, the fiber having the sine curve crimp is obtained by stretching an undrawn yarn obtained in the same manner as described above.
Once indentation crimp is applied through the crimper,
What is obtained by expressing a sine curve-shaped crimp by performing a relaxation heat treatment in a state in which the indented crimp is applied in the toe state, that is, in a constrained state that partially retains the shape of the indented crimp It is.

In the case of a fiber having a fiber cross section as in the present invention, such a cross-sectional anisotropy is easily imparted. For example, the yarn discharged from the nozzle shown in FIG. A high degree of cross-sectional anisotropy can be easily provided by rapidly cooling one side of a fiber having a single hollow portion (E1 or E2) and having a cross-sectional shape as if they were joined.

On the other hand, in the case of a single hollow fiber obtained from a conventional round hollow fiber nozzle, even if cooling air is blown to cool only one surface, the cooling air is uniformly cooled because it goes around the leeward side. As a result, it is difficult to impart a high degree of anisotropy, and as a result, it is difficult to obtain fibers having good spiral three-dimensional crimps and / or sine curve crimps.

In the present invention, it is preferable that the fiber of the present invention has an appropriate number of crimps, a crimp rate and a crimp elastic modulus described below.

That is, if the number of crimps is too small, the bulkiness is lowered, while if it is too large, the passage of the card tends to decrease. Therefore, the range of 3 to 20 peaks / 25 mm is preferable. Preferably, it is in the range of 5 to 15 peaks / 25 mm.

On the other hand, if the crimp ratio is too low, the entanglement of the fibers becomes weak, and the card passing property and the spinning property decrease, and the bulkiness tends to decrease. On the other hand, if the crimping ratio is too high, the entanglement of the fibers becomes too strong and entanglement is likely to occur, and the resulting web or spun yarn tends to be non-uniform due to reduced card passage. For this reason, the crimp ratio is preferably in the range of 6 to 50%, more preferably 12%.
４０40%.

Further, the crimp modulus is preferably at least 60%, more preferably at least 65%. If the crimp elasticity is low, the settability of the crimp is large, so the workability when applied to the card machine or subsequent processes is reduced, it is easy to wind up on cylinders and rollers, there is a lot of cotton, and the web breaks Are likely to occur, and the bulkiness is undesirably reduced.

The hollow ratio of the crimped porous hollow fiber of the present invention is 5 to 5.
The range is preferably 80%, more preferably 10 to 50%.
Range. The "hollow ratio" here is a ratio of the total area of the hollow portion in the fiber cross section to the area surrounded by the outer peripheral portion of the cross section. Explaining more specifically with reference to FIG. 3e, the total area Se of the hollow portions is defined as the hollow portions E ′ and E1.
To E4, and the area surrounded by the outer peripheral portion of the cross section is the sum of the hollow area Se and the area Sp occupied by the polymer. That is, the hollow ratio is represented by the following equation.

Hollow ratio (%) = [Se / (Se + Sp)] × 100 When the hollow ratio exceeds 80%, the hollow portion is liable to be plastically deformed by an external force, and tends to be too soft.
If it is less than 3, there is a tendency that sufficient anisotropy in the cross-sectional direction cannot be provided.

The fineness of the fiber of the present invention can be in the range of 0.1 to 100 dtex in terms of imparting anisotropy. 1.5 to 40 dtex to give higher anisotropy
Is more preferred. More preferred is 4 to 30 dtex.
It is.

Further, the crimped porous hollow fiber of the present invention shows excellent workability even when it is spun alone or mixed with another fiber and passed through a carding machine, a drawing machine or the like, and has good spinnability. Examples of the other fibers mentioned here include natural fibers such as cotton and wool, semi-synthetic fibers such as acetate and rayon, and synthetic fibers such as polyamide, polyolefin, and polyester.

As a method for producing the crimped porous hollow fiber of the present invention, the following method can be preferably employed.

For example, when producing a fiber having the fiber cross section of FIG. 2A, the fiber is discharged from the nozzle shown in FIG. It can be manufactured by blowing cooling air having a wind speed of 0.2 m / sec or more. Here, if the direction in which the cooling air is blown is significantly inclined with respect to the running direction of the discharge yarn, or if the wind speed is less than 0.2 m / sec, one side of the fiber cannot be rapidly cooled, It becomes difficult to provide a suitable cross-sectional anisotropy.

The direction in which the cooling air is blown may be any direction as long as it is perpendicular to the running direction of the discharge yarn. Preferably, the direction of the arrow shown in FIG. It is better to spray from no direction. By doing so, the cooling air flowing to the leeward side can be reduced, so that the sectional anisotropy can be further increased.

The position where the cooling air is blown is more effective as the position is closer to the spinneret surface, but it is preferably 1 to 35 cm below the spinneret surface in order to maintain good operability.

Air is most economical as a cooling gas, but any gas may be used as long as it is inert to the polymer melt, and its temperature is preferably as low as possible. To 10 to 40 ° C is preferred. The undrawn yarn thus obtained is drawn and subjected to relaxation heat treatment, whereby a spiral three-dimensional shrinkage can be developed.

As the drawing conditions at this time, it is preferable to employ the conditions that maintain the high degree of cross-sectional anisotropy imparted in the spinning step. The stretching conditions are specifically described for the case of the polyester fiber of the present invention.
g ± 20 ° C. (Tg = glass transition point of polyester) is preferable.
~ 95% is preferred. The stretching method may be any method such as liquid bath stretching and pin stretching.

In the above-mentioned relaxation heat treatment, it is preferable that each single fiber constituting the drawn yarn is made as unrestricted as possible, and then heat-treated. Heat treatment temperature is 100-230 ° C
Is preferred. Such a relaxation heat treatment may be performed in any state such as a tow shape, a multifilament shape, and a staple shape, and a mechanical crimp may be applied before the relaxation heat treatment.

Further, after the above-mentioned undrawn yarn is stretched, the indented crimp is once applied through a crimper, and then the indented crimp is applied in the tow state in a state of 4 to 20 crests / 25 mm, that is, the indented crimp. The polyester fiber having a sine-curve crimp can be obtained by performing a relaxation heat treatment in a constrained state in which a part of the shape is maintained.

[0036]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, each value in an Example was calculated | required according to the following method. 1) Intrinsic Viscosity An orthochlorophenol solution was determined at 35 ° C. according to a conventional method. 2) Fineness, fiber length, number of crimps, crimp rate, crimp elasticity Measured according to the method described in JIS-L1015. 3) Specific volume, compression ratio, recovery ratio The obtained short fiber is passed through a card to make a web,
-Measured according to the method described in L1097. 4) Card Passability The card was passed through a card under the conditions that the surface speed of the doffer was 35 m / min and the basis weight of the spun web was 50 g / m ^2, and the card passability after running for 1 hour was evaluated. Indicated as defective.

Examples 1 and 2 Polytrimethylene terephthalate (PTT) chips having an intrinsic viscosity of 0.85 are shown in Table 1.
Melt-spinning at 290 ° C from a nozzle having the cross-sectional shape shown in
Winding was performed at 50 m / min to obtain an undrawn yarn having a single fiber fineness of 22 dtex. Cooling of the discharged yarn is 1.5 to 15
The cooling air at 25 ° C. was sprayed at a flow rate of 0.8 m / sec from a direction perpendicular to the traveling direction of the yarn at the position of cm. Next, the obtained undrawn yarn was made into a tow of 780,000 decitex, and then drawn 3.5 times by a two-stage hot water drawing method at 65 ° C × 90 ° C. This drawn yarn is 64 mm
And subjected to relaxation heat treatment in a 130 ° C. atmosphere to obtain crimped cotton having a spiral three-dimensional crimp. Further, the drawn yarn is passed through a crimper to give an appropriate indentation crimp, and then subjected to a relaxation heat treatment in an atmosphere at 130 ° C., and cut into a fiber length of 64 mm to obtain a crimped cotton having a sine curve-shaped crimp. This was designated as Example 2. The resulting crimped cotton was passed through a card to make a web, and as a futon, the cross-sectional shape of the fiber was observed, and the feel was evaluated by 10 persons who were arbitrarily selected. Table 1 shows the results.

Comparative Example 1 The same operation as in Example 1 was carried out except that polytrimethylene terephthalate (PTT) was changed to polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65. Table 1 shows the results.

[0039]

[Table 1]

[Examples 3 and 4] In the same manner as in Examples 1 and 2, except that the discharge amount during spinning was changed so that the fineness of the finally obtained crimped cotton was 3.3 dtex. hand,
The crimped cotton of Example 3 and Example 4 was obtained, respectively. The obtained crimped cotton was spun and the cloth after weaving the crimped cotton was observed for the cross-sectional shape of the fiber, and the feel was evaluated by 10 persons who were arbitrarily selected. Table 2 shows the results.

Comparative Example 2 The same operation as in Example 3 was carried out except that the intrinsic viscosity was changed to polyethylene terephthalate of 0.65. Table 2 shows the results.

[0042]

[Table 2]

[0043]

Industrial Applicability The crimped porous hollow fiber of the present invention is excellent in softness and bulkiness, and hardly breaks or collapses even when subjected to severe external force during post-processing or wearing. And an effect that bulk set is hard to be generated. In particular, a crimped porous hollow fiber having a spiral three-dimensional crimp or a sine curve crimp exhibits extremely high bulkiness and bulk settling, and is excellent in card passability. Therefore, the crimped porous hollow fiber of the present invention is a carpet, a high veil, a blanket, a moquette,
It can be suitably used for woven or knitted fabric for clothing, wadding, and the like.

[Brief description of the drawings]

FIG. 1 is an example of a nozzle cross-sectional shape of a spinneret that can be used for spinning a crimped porous hollow fiber of the present invention.

FIG. 2 is an example of a nozzle cross-sectional shape of a spinneret that can be used for spinning the crimped porous hollow fiber of the present invention.

FIG. 3 is an example of a cross section of a crimped porous hollow fiber of the present invention.

FIG. 4 is an example of a cross section of a crimped porous hollow fiber of the present invention.

Continuing from the front page (72) Inventor Mikio Tashiro 77-Family Kitayoshida-cho, Matsuyama-shi, Ehime F-term in Teijin Co., Ltd. Matsuyama Office (reference)

Claims (4)

[Claims] 1. A crimped porous hollow fiber comprising a polytrimethylene terephthalate-based polyester, having a cross section of two or more hollow fibers and being crimped. 2. The crimp is a spiral three-dimensional crimp and / or
2. The crimped porous hollow fiber according to claim 1, which is a sine curve crimp. 3. The crimp according to claim 1, wherein a crimp having a number of crimps of 3 to 30 peaks / 25 cm, a crimp rate of 6 to 50%, and a crimp elastic modulus of 60% or more is provided. Shrinkable hollow fiber. 4. The crimped porous hollow fiber according to claim 1, wherein the total area of the hollow portions in the cross section is 5 to 80% of the area surrounded by the outer peripheral portion of the cross section. 2. The crimped porous hollow fiber according to item 1.