JP2003055838A - Polyester-based hollow crimped fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aromatic polyester-based fiber having both of excellent heat-insulating performance and bulky performance. SOLUTION: This polyester-based hollow crimped fiber has 3-8 hollow parts continuing in the fiber-axis direction, total area of these hollow parts in an amount of 25-60% based on an area surrounded by the outer peripheral part of fiber cross section and three-dimensional crimp based on anisotropy of cross section.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester-based hollow crimped fiber having a plurality of hollow portions continuous in the longitudinal direction and a method for producing the same.

[0002]

2. Description of the Related Art Polyester fibers represented by polyethylene terephthalate are widely used mainly for clothing and industrial applications because they are excellent in mechanical strength, chemical resistance and heat resistance. Among them, like cotton quilts,
In applications where heat retention and bulkiness are required, a method of hollowing the fiber and imparting a three-dimensional crimp to the fiber is generally adopted. In this application, attempts have been made to increase the ratio of the total area of the hollow portions in the cross-section of the fiber to the total cross-sectional area of the fiber (hereinafter referred to as the hollow ratio) in order to improve the heat retention and bulkiness of the fiber. However, a hollow fiber having a large hollow ratio is easily crushed during the processing of the fiber or the use as a product, and the heat retaining property and bulkiness of the fiber are often lost. To prevent this hollow collapse, porous hollow polyester fibers having a plurality of hollow portions in the fiber cross section have been proposed as disclosed in US Pat. No. 5,104,725. However, when attempting to obtain a porous hollow fiber having three or more hollow parts by a melt spinning method, the discharged polymer yarn flow must be cooled quickly, so the polymer temperature before discharge from the spinneret is set low. In addition, the fiber must be cooled immediately below the surface of the spinneret. Under such melt-spinning conditions, the temperature of the spinneret surface decreases, and polymer ejection failure and yarn breakage frequently occur. Further, the hollow ratio of the porous hollow fiber produced in this way was at most 20%.

Further, as a method for providing a three-dimensional crimped fiber to an aromatic polyester fiber, for example, Japanese Patent Publication No. 38-
No. 7511, Japanese Patent Publication No. 44-20497, Japanese Patent Publication No. 45-36330, etc.
Immediately after being discharged from the spinneret, the polymer yarn flow is asymmetrically cooled in the cross-sectional direction (hereinafter referred to as anisotropic cooling) to cause cross-section anisotropy in the yarn, which is taken up by spinning and relaxed after stretching. A method of developing a three-dimensional crimp by heat treatment is known. However, even though the aromatic polyester fiber produced by any method has three-dimensional crimpability, a porous hollow fiber having three or more hollow portions and having a hollow ratio of more than 20% cannot be obtained. not exist. As described above, an aromatic polyester fiber having sufficient heat retention performance and having three-dimensional crimp has not yet been provided.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an aromatic polyester fiber having sufficient heat insulating performance and having a three-dimensional crimp, and a method for stably producing the fiber. .

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a hollow hollow fiber having 3 to 8 hollow portions continuous in the fiber axis direction has a cross section of The present invention found a polyester-based hollow crimped fiber having a total area of the hollow portion in 25 to 60% with respect to the area surrounded by the outer peripheral portion of the cross section and having a three-dimensional crimp based on the cross sectional anisotropy.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The aromatic polyester of the present invention is composed of polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate homopolyester, copolyester or a polyester obtained by mixing a third component with these polyesters, and particularly 90 repeating units. Polyesters having mol% or more ethylene terephthalate units are preferred, and homopolyethylene terephthalate is most preferred. As the copolymerization component that can be copolymerized at 10 mol% or less, as the acid component, aromatic dicarboxylic acid such as isophthalic acid, 5-sodium sulfoisophthalic acid, diphenyldicarboxylic acid, naphthalenedicarboxylic acid, oxalic acid,
Aliphatic dicarboxylic acids such as adipic acid, sebacic acid and dodecanedioic acid, and oxycarboxylic acids such as P-oxybenzoic acid and P-β-hydroxyethoxybenzoic acid can be mentioned, and the diol component is 1,3-propane. Diol,
Examples thereof include aliphatic diols such as 1,6-hexanediol and neopentyl glycol, aromatic diols such as 1,4-bis (β-hydroxyethoxy) benzene, and polyalkylene glycols such as polyethylene glycol and polybutylene glycol. . These third components may be copolymerized alone or in combination of two or more.

If necessary, various additives such as matting agents, heat stabilizers, defoaming agents, color stabilizers, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers and fluorescent enhancers. Whitening agent,
Color pigments and the like can be added as necessary.

The aromatic polyester hollow crimped fiber of the present invention has a fiber cross-sectional shape as shown in FIGS. 1 (a) and 1 (b), and has a hollow portion (1 in FIG. 1) continuous in the fiber axial direction. ) Is a porous hollow fiber having 3 to 8 and a hollowness of 25.
-60% and have a three-dimensional crimp based on cross-section anisotropy.

When the number of hollow portions which are continuous in the axial direction of the fiber is 1 to 2, the hollow portions are likely to be crushed during processing of the fiber or during use as a product, and when the fiber is used as cotton, heat retention is exhibited. In addition, bulkiness is significantly reduced. 8 hollow parts
If the number exceeds the number, it is difficult to increase the hollow rate to 25% or more, and sufficient heat retention cannot be secured.
The number of hollow portions is more preferably 4 to 7 in terms of the balance between bulkiness and heat retention.

When the hollow ratio is less than 25%, when the fiber is used as cotton, the heat retaining property is not exhibited and the bulkiness is significantly reduced. When the hollow ratio exceeds 60%, even in the case of a porous hollow fiber having a support in the cross section of the fiber, hollow collapse is likely to occur due to external force, heat retention is not exhibited, and bulkiness is significantly reduced. In addition, the passability in the card process is reduced. The range of the more preferable hollow ratio is 30 to 4
It is 0%.

Further, the aromatic polyester hollow crimped fiber of the present invention must have a three-dimensional crimp based on cross sectional anisotropy. Hollow fibers having such three-dimensional crimps, in the state of cotton or opened tow, have excellent thermal insulation properties, as well as high resilience and recoverability (that is, less sagging) and high bulk performance. Demonstrate. Such bulky performance can be quantitatively evaluated by measuring compressive elasticity (compression rate and recovery rate) and bulkiness (specific volume) by the method described in JIS-L1097.

The aromatic polyester hollow crimped fiber of the present invention can be produced, for example, by the following method. In the present invention, the polymer yarn flow discharged from the spinneret is 1 to 5% by weight, more preferably 2%.
It must be in a state of containing a polyester whose main component is polylactic acid in the range of 3 wt%. Here, the polyester containing polylactic acid as a main component means a polyester containing lactic acid as a main repeating unit, and is a polymer having 50% by weight or more of L-lactic acid and / or D-lactic acid component, and poly L
-Lactic acid homopolymer, poly D-lactic acid homopolymer, L-
Lactic acid / D-lactic acid copolymers and their copolymerization and / or mixture with 50% or less of the second or third component are included. Examples of the copolymerization component include diols such as ethylene glycol, butanediol, hexanediol, octanediol and decanediol, dicarboxylic acids such as succinic acid, adipic acid and sebacic acid, aliphatic alkyls such as hydroxyalkylcarboxylic acid, pivalolactone and caprolactone. Examples include lactone and polyethylene glycol. The molecular weight is 100,000 to 300,000.
Those in the range of are preferably mentioned.

The aromatic polyester as the substrate polymer of the present invention and the polyester containing polylactic acid as a main component (hereinafter referred to as polymer B) may be mixed in a solid state with each other before the melting step. Alternatively, the melts may be joined together after they are separately melted.

In this way, for the polymer yarn flow discharged from the spinneret including the polymer B and having the discharge holes having the shapes shown in FIGS. 2 (a) and 2 (b),
A cooling air flow having a flow velocity of 0.4 to 1.0 m / sec is blown from one side of the discharged polymer yarn flow within an angle range of +20 to -20 degrees with respect to a plane perpendicular to the traveling direction of the polymer yarn flow. When applied, a remarkable structural anisotropy occurs in the polyester fiber cross section after cooling and solidification, and an excellent three-dimensional crimp is developed after heat treatment. Further, surprisingly, when the polymer B is used, a fiber cross section having a hollow ratio of 25% or more can be stably produced.

When the mixing ratio of the polymer B exceeds 5%,
During spinning, the spinnability deteriorates and the yarn breaks frequently. When the mixing ratio of the polymer B is less than 1%, the hollow ratio cannot be 25% or more, and the anisotropic cooling effect is not sufficiently imparted.

Conventionally, in order to impart sufficient cross-sectional anisotropy to the fiber by spinning the aromatic polyester alone, for example, in the case of polyethylene terephthalate fiber, a cooling air flow having a flow velocity of 1.0 m / sec or more is used. It was necessary to spray from one side, and there was a phenomenon of poor spinnability due to the temperature decrease of the spinneret surface. On the other hand, in the method of the present invention using the polymer B, a sufficient anisotropic cooling effect is imparted by blowing cooling air at a flow rate of 0.4 m / sec or more. If the flow velocity of the cooling air exceeds 1.0 m / sec, a phenomenon of poor spinnability occurs due to the temperature drop of the surface of the spinneret and must be avoided. Further, by setting the flow velocity of the cooling air to 0.5 to 0.8 m / sec, the spinning operation can be performed in a more preferable state.

The cooling air stream must be blown onto the discharged polymer yarn stream at an angle of +20 to -20 degrees with respect to the plane perpendicular to the traveling direction of the discharged polymer yarn stream. If the angle at which the cooling airflow is blown exceeds +20 to -20 degrees with respect to the plane perpendicular to the traveling direction of the discharged polymer yarn flow, the running state of the polymer yarn flow is disturbed, frequent spinning breaks occur, and anisotropy occurs. The cooling effect is also reduced. In addition, it is more preferable to blow the cooling air substantially perpendicularly to the traveling direction of the polymer yarn flow.

The unstretched fibers that have been taken out after cooling and solidification are then stretched by a stretching device equipped with a hot water bath and the like, subjected to relaxation heat treatment in a state where there is less constraint between the fibers, and then cut into a predetermined length. A polyester hollow fiber having a spiral three-dimensional crimp is obtained.

In some cases, the polyester hollow crimped fiber of the present invention may be opened in a tow state without being cut into short fibers, and may be used for non-woven fabric, futon, etc.

[0020]

EXAMPLES Next, the present invention will be described in detail with reference to examples. Each item in the examples was measured by the following method. (1) Intrinsic viscosity Using orthochlorophenol as a solvent, the viscosity was measured with an Ubbelohde viscosity tube at a temperature of 35 ° C. (2) Hollow ratio The cut surface of the fiber is photographed, the area of the hollow part and the single fiber cross section is measured for 20 cross sections, and the average value of the area percentage (%) of the hollow part to the area of the single fiber cross section is calculated. The hollow rate was used. (3) Fineness, fiber length, number of crimps, and crimp rate were measured according to the method described in JIS-L1015. (4) Heat retention The short fibers obtained are passed through a card to make a web
Based on the flat plate comparison method described in A1412, the density of 0.
Thermal conductivity of card web of 01 g / cm ³ (W / (m ·
It was judged by measuring K)). The smaller the thermal conductivity, the better the heat retention. (5) Bulk high performance The obtained short fibers are passed through a card to make a web
The bulk performance (specific volume, compressibility and recovery rate) described in L1097 was measured. (6) Card passability The card was placed on 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 passing state when operating for 1 hour was observed. It was judged by. Level 1: Passing the card, there is no wrapping of fiber around the cylinder. Level 2: Passes through the card, but fiber winding around the cylinder is seen. Level 3: The web does not come out of the card. (7) Spinning stability The spinning machine was operated for 10 days, and the number of yarn breakages that occurred was recorded.

[Example 1] Polyethylene terephthalate chips having an intrinsic viscosity of 0.64 were used as Polymer B
Shimadzu Corporation “Lacty # 9020” chips (polylactic acid, weight average molecular weight 200,000, melting point 175 ° C.) 3
The mixture uniformly mixed by weight% was dried at 160 ° C. for 7 hours, then melted at 290 ° C., and discharged from a spinneret having 150 discharge holes having the shape shown in FIG.
Discharge in minutes, and the top of the outlet is 2 from the polymer discharge surface.
20 cm long and 20 c wide installed to be 0 mm
The cooling air of 25 ° C is 0.8 from the cooling air outlet of m.
The unstretched polyethylene terephthalate fiber was obtained by spraying from one side of the polymer stream at a flow rate of m / sec at an angle perpendicular to the direction of advance of the yarn, and spun off at a speed of 1200 m / min.

Next, the unstretched fibers obtained were aligned to a tow of 500,000 decitex, and then the first stage stretching temperature was 70.
℃, the second stage drawing temperature 90 ℃ hot water drawing 2.46 times,
After cutting into a fiber length of 64 mm, relaxation heat shrinkage treatment was performed at 135 ° C. to have a fiber cross section as shown in FIG. 1 (a), a fineness of 12.4 decitex, a hollow ratio of 38%, and a crimping number of 9. A polyethylene terephthalate hollow crimped fiber having 3 peaks / 25 mm and a crimping rate of 30.7% was obtained. The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

Comparative Example 1 A polyethylene terephthalate chip having an intrinsic viscosity of 0.64 was dried at 160 ° C. for 7 hours and then melted at 290 ° C. to form 150 discharge holes having the shape shown in FIG. From the spinning spinneret at a discharge rate of 480 g / min.
20 cm in length and 20 cm in width installed to be mm
Cooling air of 25 ° C from the cooling air outlet of
The unstretched polyethylene terephthalate fiber was obtained by spraying from one side of the polymer flow at an angle perpendicular to the yarn advancing direction at a flow rate of / sec and taking it off by spinning at a speed of 1200 m / min.

Next, the unstretched fibers obtained were aligned in a tow of 500,000 decitex, and then the first stage stretching temperature was 70.
℃, the second stage drawing temperature 90 ℃ hot water draw 2.40 times,
After cutting to a fiber length of 64 mm, it was subjected to relaxation heat shrinkage treatment at 135 ° C., and had a fiber cross section as shown in FIG. 1 (a), a fineness of 12.3 decitex, and a crimp number of 8.5 peaks / 25.
mm and a crimping rate of 28.6% were obtained as polyethylene terephthalate hollow crimped fibers. The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[Example 2] The content of the polymer B was 1.0.
1% decitex having a fiber cross section as shown in FIG. 1 (a), a hollow ratio of 30%, and a crimping number of 9.4 threads / 25 mm by the same manufacturing method as in Example 1 except that the weight% is used.
And polyethylene terephthalate hollow crimped fibers having a crimping rate of 29.4% were obtained. The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[Example 3] The content of the polymer B was 5.0.
1% decitex having a fiber cross section as shown in FIG. 1 (a), a hollowness of 35%, and a crimping number of 8.9 threads / 25 mm by the same manufacturing method as in Example 1 except that the weight% is used.
And polyethylene terephthalate hollow crimped fibers having a crimping rate of 32.2% were obtained. The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[Embodiment 4] FIG. 1 is manufactured by the same manufacturing method as in Embodiment 1 except that a spinneret having 150 discharge holes having the shape shown in FIG. 2B is used to discharge at a discharge rate of 480 g / min.
A polyethylene terephthalate hollow crimped fiber having a fineness of 12.3 decitex, a hollowness of 27%, a crimp number of 8.9 threads / 25 mm and a crimped rate of 29.3%, having a fiber cross section as shown in (b), was obtained. . The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[Comparative Example 2] [0028] The same manufacturing method as in Example 1 was repeated except that the spinneret having 150 discharge holes having the shape shown in Fig. 2C was used to discharge at a discharge rate of 480 g / min.
A polyethylene terephthalate hollow crimped fiber having a fineness of 12.5 decitex, a hollowness of 18%, a crimping number of 6.3 crests / 25 mm and a crimping rate of 18.2% having a fiber cross section as shown in (c) was obtained. . The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[Embodiment 5] The same manufacturing method as in Embodiment 3 was repeated except that cooling air was blown at a flow rate of 1.0 m / sec from one side of the polymer stream at an angle perpendicular to the traveling direction of the yarn. With a fiber cross section as shown in 1 (a), fineness 12.4 decitex, hollowness 55%, crimp number 8.9 threads / 25 mm
And polyethylene terephthalate hollow crimped fibers having a crimping rate of 31.5% were obtained. The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[Comparative Example 3] The content of the polymer B was 6.0.
1% decitex with a fiber cross section as shown in FIG. 1 (a), a hollowness of 65%, and a crimp number of 11.4 threads / 25 m by the same manufacturing method as in Example 5 except that the weight% was used.
m and a polyethylene terephthalate hollow crimped fiber having a crimping rate of 32.3% were obtained. The obtained fiber was passed through a card to form a web, and its heat retention performance and bulk performance were measured. The results of the implementation are summarized in Table 1.

[0031]

[Table 1]

[0032]

EFFECTS OF THE INVENTION The present invention provides a polyester type hollow hollow three-dimensional crimped fiber having a high hollow ratio, which is rich in bulkiness, has less sagging, and is excellent in heat retention.
At the same time, excellent process stability with less yarn breakage during spinning,
Provided is a method for producing a high hollow porosity three-dimensional crimped fiber.

[Brief description of drawings]

1A and 1B are schematic views for explaining a cross section of a polyester hollow crimped fiber of the present invention. (C) is a schematic diagram for demonstrating the cross section of the polyester hollow crimped fiber of the comparative example 2.

2 (a) and 2 (b) are schematic views showing an embodiment example of a discharge hole shape of a spinneret used in the present invention. FIG. 3C is a schematic view showing an embodiment example of the discharge hole shape of the spinneret used in Comparative Example 2.

[Explanation of symbols] 1: Hollow section of fiber 2: Spinneret discharge hole opening

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4L035 BB21 BB56 DD19 DD20                 4L036 MA05 MA19 MA35 PA01 PA03                       RA04 UA25                 4L045 AA05 BA03 BA24 CB08 CB18                       DA23

Claims (2)

[Claims] 1. A porous hollow fiber having 3 to 8 hollow portions continuous in the fiber axis direction, and the total area of the hollow portions in the cross section is 25 with respect to the area surrounded by the outer peripheral portion of the cross section.
Polyester hollow crimped fiber having a three-dimensional crimp based on cross-section anisotropy of 60% to 60%. 2. A spinneret having ejection holes capable of forming a porous hollow cross section by mixing aromatic polyester with polyester containing polylactic acid as a main component in a proportion of 1 to 5% by weight and then melting or mixing after melting. More discharge, 0.4-1.0
A cooling air flow having a flow rate of m / sec is discharged from one side of the polymer yarn flow by +20 with respect to a plane perpendicular to the traveling direction of the polymer yarn flow.
The method for producing a polyester-based hollow crimped fiber according to claim 1, wherein after being blown within a range of an angle of from -20 degrees, the unstretched fiber is taken out, and then the unstretched fiber is stretched and subjected to a relaxation heat treatment.