JP2932721B2 - Polyester fiber and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a brilliant and unique gloss, opacity, dry touch, sharpness, tension,
The present invention relates to a polyester fiber having a polygonal hollow section suitable for a woven or knitted fabric for high-grade clothing, which is excellent in waist, lightness, and has a natural color of marbling by dyeing, and a method for producing the same.

[0002]

2. Description of the Related Art There have been many proposals to use fibers of irregular cross-section or hollow fibers to impart high-grade feeling such as glossiness, dry touch and light weight to woven or knitted fabric for polyester clothing. T, Y, and T
For example, the fiber having a hollow cross section includes a hollow round cross section. These woven and knitted fabrics having irregular cross-section fibers and hollow cross-section fibers have characteristic glossiness, texture, and lightness as compared with the round cross-section, and are preferably used for clothing. In addition, some fibers have been proposed which combine the two properties of the excellent texture properties of the modified cross-section fibers and the lightweight properties of the hollow cross-section fibers. For example, Japanese Patent Publication No. 44-1892
No. 3 proposes a polygonal section fiber having a hollow portion, and Japanese Patent Publication No. 57-49650 proposes a hollow fiber section having a hollow section. However, since these modified cross-section fibers are all produced by single-component spinning, the apex of the fiber cross section is rounded due to the effect of surface tension during the cooling process after discharging from the die, and a cross-sectional shape having a sharp portion is obtained. Absent. Therefore, these characteristics are not satisfied in the field of clothing that requires a glossiness, a sense of fashion, and the like.

[0003] In recent years, under various demands, there have been proposed several modified cross-section fibers having a sharp apex portion to which a composite spinning technique is applied. For example, Japanese Unexamined Patent Publication No. 56-159316 proposes a method of obtaining a modified cross-section fiber having a sharp edge by hydrolyzing one component of a multi-layered composite yarn. Although the technology such as dry touch has excellent texture, the cross-sectional shape with unevenness does not provide a high-quality, brilliant luster, and also leaves some components that are highly hydrolyzable. After dyeing the knit, it also has drawbacks such as easy spotting.

Further, Japanese Patent Publication No. 58-4092 discloses that
A hemp-like irregular shaped hollow fine fiber has been proposed and emits good marbling, but lacks sharp apexes and lacks texture such as squatting feeling, tension and waist. Is not preferred.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a unique and brilliant luster, excellent opacity and a waxy feeling, which could not be achieved by the above-mentioned prior arts or their combination. An object of the present invention is to provide a fiber suitable for woven or knitted fabrics for high-grade clothing, which has excellent dry touch, smooth feeling, tightness and waist, light weight feeling, and has a marbling natural color tone by dyeing, and a method for producing the same.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to change the cross-sectional area in the direction of the fiber axis so that the thickness ratio is 1.2 to 1.2.
2.2, and the hollow ratio in one hollow portion is 10 to 4
A fiber having a hollow portion which is 0% , and a radius of curvature of a vertex in a cross section of the fiber satisfies the following range;
A polyester fiber characterized by being a polygon of not less than a triangle and not more than a hexagon in which a variation rate of a side portion between adjacent apexes is 10% or less. r ≦ d ^0.5 r: radius of curvature (μm) at the apex of the fiber cross section d: single fiber fineness (denier)

Hereinafter, the present invention will be described in detail. Fiber of the present invention, each single fiber has a change in cross-sectional area in the fiber axis direction,
Its thickness ratio must be between 1.2 and 2.2. When the thickness ratio is less than 1.2, there is almost no natural unevenness originally caused by the difference in the cross-sectional area, so that only a feeling that is not much different from that of ordinary polyester fibers can be obtained. On the other hand, if the thickness / thickness ratio exceeds 2.2, problems often arise in terms of handling of fibers, and fibers having sufficient strength cannot be produced from the relationship with the birefringence. Preferably, the thickness ratio is 1.3 to 2.0, and more preferably, 1.4 to 1.8. In addition, the thickness ratio of the fiber referred to in the present invention is the ratio of the cross-sectional area including the hollow portion of the thick portion and the thin portion in the fiber axis direction (thick fineness portion / fine fineness portion). This is a value calculated using the average value.

The fiber of the present invention has a hollow ratio of 10-4.
Must be in the range of 0%. If the hollow ratio is less than 10%, not only the effect as a lightweight material is reduced, but also the opacity is impaired. The hollow ratio is 40%
When the ratio exceeds, the shape retention is remarkably deteriorated, so that the hollow portion is crushed and the cross section is deformed in the steps after weaving, so that the object of the present invention cannot be achieved. For the reasons described above, the optimum hollow ratio is in the range of 20 to 35%.

Next, the curvature radius of the apex portion and the variation rate of the side portion in the cross section of the fiber of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a fiber for explaining the cross-sectional shape of the fiber of the present invention, wherein 1 is a fiber, 2 is a hollow portion,
Is a quadrangular hollow cross section fiber consisting of a vertex portion and 4 a side portion. First, the radius of curvature r of the vertex 3 in the cross section of the fiber of the present invention must be d ^0.5 μm or less. For example, if the single fiber fineness d is 1 denier, the radius of curvature r of the apex portion 3 is 1.0 μm or less, and if it is 3 denier, it is about 1.7 μm.
It is as follows. This is because the cross-sectional shape formed by gentle vertexes having a radius of curvature r exceeding d ^0.5 μm cannot sufficiently exhibit dry touch and sense of smear. Preferably, the radius of curvature r at the vertex is (d / 2) ^0.5 μ
m, and more preferably (d / 3) ^0.5 μm or less.

Next, in the present invention, the variation rate of the side portion between the adjacent vertices is important. In FIG. 1, a reference line L is drawn on each side between the adjacent vertices 3. The reference line L is L
Is drawn so as to minimize the area of the side portion formed by adding the concave portion and the convex portion. At this time, the reference line L
Let T be the point farthest away from T and t be the distance between T and L.
On the other hand, in the reference line L corresponding to the side where T is present, when the length between the intersections with the adjacent reference line L is s, the variation rate of the side in the cross section of the fiber is determined by the following equation. . Fluctuation rate (%) = (t / s) × 100 In the cross section of the fiber of the present invention, the fluctuation rate of the side portion between the adjacent vertices must be 10% or less. The variation rate is closely related to glossiness and surface touch, and a cross-sectional shape having a side having a variation rate of more than 10% does not exhibit a distinctive gloss. The volatility is preferably 8
%, More preferably 5% or less.

FIG. 2 is a cross-sectional view showing an example of the cross-sectional shape of the fiber of the present invention. 2A is a triangle, and FIG.
Is an example of a square, FIG. 2C is an example of a pentagon, and FIG. 2D is an example of a hexagon. In order to exhibit the effect of the present invention, it is necessary to have a polygonal cross section of a triangle or more and a hexagon or less. If the cross section is a polygon of a heptagon or more, the vertex in the cross section is not sharp, so that the dry touch and the sense of smear, which are the objects of the present invention, cannot be satisfied. Further, in order to further exhibit the above-mentioned characteristics, the shape is preferably a pentagon or less.

Next, a specific example of the method for producing a fiber of the present invention will be described in detail. In producing the fiber of the present invention, first, a hollow conjugate fiber comprising an outer layer and an inner layer is obtained, and then the outer layer of the conjugate fiber is dissolved and removed. The outer layer component of the conjugate fiber used in the present invention needs to copolymerize 1.5% by mole or more of 5-sodium sulfoisophthalic acid component with polyethylene terephthalate. This is because it is necessary to provide a dissolution rate difference between the inner layer component and the outer layer component in order to leave the inner layer component polyethylene terephthalate as it is and dissolve and remove only the outer layer component. At this time, an alkaline solution (for example, a hot aqueous solution of sodium hydroxide) is used as a solvent for dissolving only the outer layer component. However, if the copolymerization amount is less than 1.5 mol%, the alkali solution with the inner layer component is used. Since the difference in dissolution rate with respect to the solution is small, the top portion of the inner layer portion is dissolved and rounded, and the cross-sectional shape intended by the present invention cannot be obtained. The copolymerization rate is preferably at least 2.0 mol%, more preferably at least 3.0 mol%. On the other hand, if the copolymerization ratio is too high, not only the strength of the conjugate fiber is significantly reduced, but also
The copolymerization ratio is preferably 6.0 mol% or less, since it has disadvantages such as increased solubility in hot water and generation of sticking between single fibers in the production process.

The outer layer component must have an intrinsic viscosity [η] of at least 0.34. If the intrinsic viscosity [η] of the outer layer component is too low, not only does the yarn-forming property such as yarn breakage during spinning deteriorate, but also, if possible, yarn breakage is likely to occur in higher-order processing.

The intrinsic viscosity [η] of polyethylene terephthalate, which is an inner layer component of the conjugate fiber used in the present invention, must be 0.70 or more. As described later,
In the fiber of the present invention, the hollow portion plays a large role in improving the feeling of the fabric. At the stage of forming this hollow part,
In order to obtain a higher hollow ratio, it is necessary to increase the melt viscosity of the polymer in the spinning stage. Further, in the process of producing the fiber of the present invention, a high rate of weight reduction processing is performed in the state of the fabric, but at this stage, there is a problem that the strength of the fabric is remarkably reduced and the tear strength is low. Therefore, it is necessary to increase the intrinsic viscosity [η] of the inner layer in order to maintain the tear strength which does not pose a practical problem even after the outer layer is eluted. For the above two reasons, the intrinsic viscosity [η] needs to be 0.70 or more, preferably 0.72 or more, and more preferably 0.75 or more. Also, if the intrinsic viscosity [η] is too high, various problems such as a high pressure loss in the spinning stage occur, so the intrinsic viscosity [η] is preferably 1.0 or less.

The two kinds of polymers composed of the inner layer component and the outer layer component described above are separately melted and weighed to obtain hollow composite fibers. FIG. 3 is a longitudinal sectional view of a main part of a composite die device preferably used in the present invention. FIG. 4 is a bottom view of a base showing an example of a base hole shape used in the present invention. FIG. 5 is a bottom view of the base for explaining the base hole shape of FIG. 3 to 5, reference numeral 5 denotes an upper introduction plate, 6 denotes a lower introduction plate, 7 denotes a base, and 8 denotes a slit. The polymer A of the inner layer component is introduced from the upper introduction plate 5, and the polymer B of the outer layer component is introduced.
Is introduced from the lower introduction plate 6, becomes a combined flow of the inner and outer layers at the base 7, and is discharged from the slit 8.

As described above, two kinds of polymers are discharged from the slit 8 as an inner / outer layer composite flow. In the present invention, the melt viscosity of the inner layer component is set to be 1.2 to 6 times the outer layer component. There is a need. By making the melt viscosity of the inner layer component higher than that of the outer layer component, the composite flow of polymer discharged from each slit bends toward the inside of the slit, and both ends collide and fuse with each other to join, and the inner layer portion This forms a conjugate fiber having a hollow cross section having a polygonal cross section.

By the way, in order to ensure that the composite polymer flow discharged from each slit collides and fuses and to stably produce the intended inner layer having a sharp cross section, the melt viscosity of the inner and outer layer components is required. Need to be optimized. If the melt viscosity of the inner layer component is less than 1.2 times the melt viscosity of the outer layer component, the sides in the cross section of the fiber obtained after eluting the outer layer components will swell in an arc shape, and the apex will also be rounded. In addition, lack of dry touch, tension and waist, and glossiness is also difficult. Furthermore, in order to make the apex portion in the cross section of the fiber of the present invention sharper and to improve the linearity of the side portion, it is more preferable that the melt viscosity of the inner layer component is 1.5 times or more the outer layer component. . When the melt viscosity of the inner layer component exceeds 6 times that of the outer layer component, collision and fusion of the polymer composite flow immediately below the mouthpiece become unstable, and as a result, a composite abnormality occurs and the cross section changes with time. Therefore, it is impossible to obtain the desired fiber having a polygonal hollow cross-sectional shape. For more stable production, the melt viscosity of the inner layer component is preferably 5 times or less, more preferably 4 times or less, the melt viscosity of the outer layer component.

Here, the shape of the base hole to be finally discharged will be described with reference to FIG. 5 which illustrates a base hole formed of four divided slits in FIG. 4B. The radius of curvature h of the slit 8 is
From the hole center Q to the slit center P (slit length x
It is preferable that the annular arrangement is 0.8 to 1.2 times the distance (hereinafter, referred to as a die radius i) to the intermediate point in the width w. This is because, when the shape of the slit is within the above-mentioned range, when viewed at the stage of the conjugate fiber, the outer peripheral shape of the cross section is circular, for example, when dissolving and removing the outer layer component after knitting and weaving, the conjugate fiber becomes Even if the cross section of the fiber becomes polygonal after dissolving the outer layer components, it is arranged in a random state in the knitted fabric, so that the knitted fabric is naturally This is because it gives a natural texture.

The above-mentioned four-divided slits are preferably formed by arranging four slits having the same hole shape and the same size in a point-symmetrical manner, as shown in FIGS. In the case of division, three slits as shown in FIG. 4 (a), in the case of five divisions, five slits as shown in FIG. 4 (c), and in the case of six divisions, FIG. 6 as shown
The slits are arranged point-symmetrically.

It is essential that the number of slits constituting a single hole is 3 or more and 6 or less. The number of apexes and sides of the polygonal hollow cross-section fiber is equal to the number of slits forming a single hole, so that if it is divided into three, it becomes a triangular hollow cross-section fiber, and if it is divided into six, it becomes a hexagonal hollow cross-section fiber. is there. Therefore, if the number of slits constituting a single hole is not in this range, the polygonal hollow cross section fiber aimed at by the present invention cannot be obtained.

Further, as described above, the two kinds of polymers are discharged in each slit in the state of the inner and outer layers. It is necessary that the compounding ratio of the inner layer portion at the time of ejection be 40% by weight or more and 75% by weight or less in order to keep the variation rate of the side portion in a desired range and sharpen the top portion. Preferably, the composite ratio of the inner layer portion is in the range of 45 to 65% by weight.

The spinning speed at the time of spinning is preferably 1800 to 3500 m / min.
The effect of this spinning speed will be clearly described in Examples, but if the spinning speed is less than 1800 m / min, the degree of orientation in the thick portion after drawing at a low magnification to form a fine fiber, that is, in the undrawn portion, is reduced. Due to the low crystallization, the fibers become brittle by crystallization in a finishing step or a dyeing step after forming the knitted fabric, so that they are easily broken by an external force and are difficult to use in practical use. On the other hand, when the spinning speed exceeds 3500 m / min, it is difficult to obtain a fiber having a desired thick / fine ratio due to a small thickness / thin ratio between a thick portion and a thin portion even when drawing at a low magnification.

The conjugate fiber obtained by the above-mentioned method must be drawn at the following draw ratio. Stretching ratio = 1 + (constant tension elongation area elongation × K) / 100 0.6 ≦ K ≦ 1.2 Here, if the coefficient K is less than 0.6, there are many unoriented portions with low orientation. After dyeing the knitted fabric, most of the dark-colored portions are occupied, and the natural color tone aimed at by the present invention cannot be obtained. On the other hand, if the coefficient K has a stretching ratio exceeding 1.2, the thick portion hardly exists, so that the color tone of marbling does not appear after dyeing,
The object of the present invention cannot be achieved. The above-described constant tension elongation region elongation is a value measured by a low-speed tensile tester, and is an elongation (%) from a measurement start point M to a point N at which necking elongation is completed in the tension-elongation curve of FIG. Is shown.

In addition, the composite thin fibers obtained by the above-mentioned method are eluted by a solvent treatment of the outer layer component in an appropriate step thereafter, and the inner layer component is left by leaving the inner layer component.
When the bases of (a), (b), (c) and (d) are used, polygons as shown in (a), (b), (c) and (d) of FIG. A hollow section fiber can be obtained. As the solvent in this case, an alkaline solution is preferably used, and particularly preferably, a hot aqueous sodium hydroxide solution. This treatment may be performed in any step, but is preferably performed after weaving or knitting in view of production stability.

[0025]

The present invention will be described in more detail with reference to the following examples. Each characteristic value in the examples was obtained by the following method. A. Hollow ratio The hollow ratio was calculated by the following formula from the cross-sectional photograph after the raw yarn as a sample was treated with a 4% by weight hot aqueous solution of sodium hydroxide to dissolve and remove the outer layer. Hollow ratio (%) = cross-sectional area of hollow part / fiber cross-sectional area including hollow part × 100 Strength after Elution of Outer Layer Components After treating the raw yarn as a sample with a 4% by weight hot aqueous solution of sodium hydroxide to dissolve and remove the outer layer, a tensile test was conducted with Tensilon UCT-100 manufactured by Orientec Co., Ltd. The strength was calculated based on the fineness after elution of. (Strength after elution of outer layer portion) = (tensile strength) / (fineness of inner layer portion) (g / d) Elongation at constant tension elongation range Unstretched yarn to be used as a sample is Orientec Tensilon U
A tensile test was performed using CT-100, and the elongation (%) from the measurement start point M to the point N at which necking elongation was completed was measured as the elongation (%) in the constant tension elongation region. D. Feeling characteristics (coolness, glossiness, lightness, color tone) For each item, a sensory test was performed by a pairwise comparison of the sample with a reference sample, and evaluated on a four-point scale. And when they are comprehensively evaluated, "Excellent" is ◎, "Excellent"
Is ○, inferiority is △, and “extremely inferior” is ×
Indicated by The reference sample is a Y-section polyester fiber having the same fineness and the same number of filaments as the sample original yarn used as a standard product, and is woven and processed in the same manner as the sample. " E. FIG. Melt Viscosity The melt viscosity is a value measured by a melt indexer type MX-101-B manufactured by Takara Kogyo Co., Ltd. at a shear rate of 30 (1 / SEC) at the same temperature as the spinning temperature.

Example 1 Polyethylene terephthalate having an intrinsic viscosity [η] of 0.72 was used as an inner layer component, and a 5-sodium sulfoisophthalic acid component having an intrinsic viscosity [η] of 0.42 was used as an outer layer component. 3 using a core-sheath composite spinneret shown in FIG. 3 at a spinning temperature of 295 ° C. using a conventional composite spinning machine, using the modified polyester copolymerized in an amount of 0.2 mol%, and from the center of the die hole shown in FIG. The inner layer is discharged at a composite ratio of 60% by weight from an annular four-slit hollow hole having a distance i of 0.6 mm and a slit radius of curvature h of 0.6 mm at a spinning speed of 2500 m / min. Wound up. Inner layer components,
The melt viscosity of each single polymer of the outer layer component is 4200 pois
e, 1600 poise, and the viscosity ratio was about 2.6 times. Further, the elongation at a constant tension elongation region was 78%. This undrawn yarn is woven as a warp and a weft by drawing a multifilament conjugate fiber obtained by drawing the undrawn yarn at a drawing temperature of 80 ° C. and a draw ratio of 1.7 by a usual drawing machine, relaxed scouring at 98 ° C., and intermediate at 180 ° C. After setting, the mixture was treated with a 4% by weight aqueous solution of sodium hydroxide at 98 ° C. to elute the outer layer components.
A 5-denier 36 filament was prepared and set at 170 ° C. to obtain a habutae.

The obtained samples were subjected to a sensory evaluation. As a result, the texture was unattainable with the conventional woven fabric using a modified cross-section polyester fiber, and all of the texture characteristics were extremely excellent. The results are shown in Tables 1 and 2.

Example 2 The spinning speed was set to 180, with the composite ratio of the inner layer being 75% by weight.
Example 1 except that 0 m / min and the draw ratio were 2.1 times.
The same conditions were used. The results of the obtained samples are shown in Tables 1 and 2. The sample of Example 2 is better than the conventional product in that it has a moderate feeling of smoothness, tension and waist, glossiness and lightness, and the color tone after dyeing is very good in a natural marbling state. Was.

Example 3 Example 3 was carried out under the same conditions as in Example 1 except that the spinning speed was 3500 m / min and the draw ratio was 1.3. The results of the obtained samples are shown in Tables 1 and 2. The sample of Example 3 had excellent texture characteristics. Also,
The color tone after dyeing was also better than the conventional product.

Comparative Example 1 The operation was performed under the same conditions as in Example 1 except that the composite ratio of the inner layer was changed to 90% by weight. The results of the obtained samples are shown in Tables 1 and 2. The sample thus obtained has a rounded outer periphery with an arc-shaped bulge inward, and the vertex is also rounded, so that it has less stiffness, tension and stiffness than the sample of Example 1, and is inferior in glossiness. Was something.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the spinning speed was 1500 m / min and the draw ratio was 2.1 times. The results of the obtained samples are shown in Tables 1 and 2. The obtained sample had a large ratio of 2.3 to 2.3, and the orientation of the thick portion was low, so that it became brittle even at the stage of relaxing scouring, and was not practical.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the spinning speed was 4000 m / min and the draw ratio was 1.2 times. The results of the obtained samples are shown in Tables 1 and 2. The obtained sample had a small and large ratio of 1.15, and the color tone after dyeing was not much different from ordinary polyester fibers.

Comparative Example 4 The same procedure as in Example 1 was carried out except that the intrinsic viscosity [η] of the inner layer component was set to 0.60 and the intrinsic viscosity [η] of the outer layer component was set to 0.28. Table 1 shows the obtained results as Comparative Example 4.
And Table 2. The sample of Comparative Example 4 having a hollow ratio of 5% has smoothness but no tension or stiffness,
Both opacity and lightness were inferior to conventional products.

Comparative Example 5 Example 1 was repeated except that the composite ratio of the inner layer was 35% by weight.
The same conditions were used. The obtained results are shown in Tables 1 and 2 as Comparative Example 5. In the sample of Comparative Example 5 having a hollow ratio of 43%, fibrillation occurred on the entire surface of the woven fabric in the dyeing step, and all the textures were inferior to those of Example 1.

Comparative Examples 6 and 7 The same procedure as in Example 1 was carried out except that the draw ratio was 1.35 times and 2.1 times. The results of the obtained samples are shown in Tables 1 and 2. The sample of Comparative Example 6 was excellent in refreshing feeling such as squat feeling, tension and waist, but the color tone after dyeing showed a tendency to become darker overall due to the high ratio of unstretched parts, It was not very good. Further, since the sample of Comparative Example 7 has almost no unstretched portion,
The color tone after dyeing was not much different from ordinary polyester fiber.

Examples 4, 5 and 6 Except that the polymer composition and the degree of polymerization of the outer layer components were changed,
The operation was performed under the same conditions as in Example 1. Table 1 shows the obtained results.
And Table 2. Example 4 in which the ratio of the viscosity of the inner layer component to the outer layer component was 1.2 times that of the sample of Example 4 in which polyethylene terephthalate obtained by copolymerizing 1.8 mol% of 5-sodium sulfoisophthalic acid component was 1.2 times. Each of the samples had a refreshing feeling such as a feeling of shaking, tension and waist, and also had excellent properties such as a brilliant glossy feeling and a lightweight feeling. Further, the sample of Example 6 in which the ratio of the viscosity of the inner layer component to the outer layer component was 6 times was excellent in the sense of smell.

Comparative Example 8, Comparative Example 9, Comparative Example 10 The same procedure as in Example 1 was carried out except that the polymer composition and the degree of polymerization of the outer layer component were changed. The obtained results are shown in Tables 1 and 2. In the sample of Comparative Example 8 in which polyethylene terephthalate obtained by copolymerizing 1.2 mol% of 5-sodium sulfoisophthalic acid component was used as an outer layer component, the outer layer portion was completely treated by a 4% by weight sodium hydroxide 98 ° C. hot aqueous solution treatment after weaving. As a result, the apex of the cross section of the inner layer was also reduced, so that the apex was rounded, resulting in not only a feeling of shaking but also inferior tension and waist. In the sample of Comparative Example 9 in which the viscosity ratio of the inner layer component to the outer layer component was 1.1 times, the side portion of the inner layer section bulged inward in an arc shape, and the variation rate of the cross-sectional circumferential shape was as high as 15%. There was no feeling of shaking, and the texture was inferior with a glossy luster. Also,
In Comparative Example 10 having a viscosity ratio of 6.5 times, a composite abnormality occurred during spinning, and a sample could not be obtained because of poor spinning properties.

Embodiment 7 The base to be discharged is a slit having a distance i from the center of the base hole to the center of the slit shown in FIG. 4A of 0.6 mm and a radius of curvature h of the slit of 0.6 mm. The procedure was performed under the same conditions as in Example 1 except that the hollow holes were divided into three. The obtained results are shown in Tables 1 and 2. The sample has the cross-sectional shape shown in FIG. 2 (a), and has a distinctive glossiness that is even higher than that of the sample of Example 1, and is excellent in sense of shaking, tightness, waist, and opacity. It was.

Example 8 A die to be discharged is constituted by a slit having a distance i from the center of the die hole to the center of the slit shown in FIG. 4D of 0.6 mm and a radius of curvature h of the slit of 0.6 mm. The procedure was performed under the same conditions as in Example 1 except that the hollow holes were divided into six. The obtained results are shown in Tables 1 and 2. The sample has a cross-sectional shape shown in FIG.
The opacity, tightness and waist were good, and the texture was soft and favorable.

Comparative Example 11 The nozzle to be discharged was a seven-segment hollow hole formed by a slit having a distance i from the center of the die hole to the center of the slit of 0.6 mm and a radius of curvature h of the slit of 0.6 mm. Except for the above, the same conditions as in Example 1 were used. The obtained results are shown in Tables 1 and 2. Although the sample of Comparative Example 11 was a hollow fiber with a heptagonal cross section, it was poor in refreshing feeling such as shaking feeling, tension and waist, and had no characteristic.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

The present invention relates to a polyester fine fiber having a polygonal hollow section having a sharp apex and a high hollow ratio, which cannot be achieved by the prior art, and a method for producing the same. The fiber of the present invention has a unique glossy and opaque feeling that is brilliant, and also has excellent properties such as dry touch, shaping, tension and waist, light weight, and color tone after dyeing. It is most suitable as a refreshing material for clothing that could not be obtained with cross-section fibers.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a fiber for explaining a cross-sectional shape of the fiber of the present invention.

FIG. 2 is a cross-sectional view showing an example of a cross-sectional shape of the fiber of the present invention.

FIG. 3 is a vertical sectional view of a main part showing an example of a composite die device used in the present invention.

FIG. 4 is a bottom view of a base showing an example of a base hole shape used in the present invention.

FIG. 5 is a bottom view of the base for explaining the hole shape of FIG. 4;

FIG. 6 is a graph showing a tension-elongation curve of an undrawn yarn for explaining elongation in a constant tension elongation region in the present invention.

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI // D01F 8/14 D06M 5/02 G D06M 101: 32 F (56) References JP-A-2-74667 (JP, A) JP-A-61-132620 (JP, A) JP-A-4-257314 (JP, A) JP-A-54-50620 (JP, A) Patent 2569830 (JP, B2) JP-B-60-7723 (JP, B2) (58) Fields surveyed (Int.Cl. ⁶ , DB name) D01F 6/62 303 D01D 5/24 D01D 5/253 D06M 11/38 D01F 8/14

Claims (2)

(57) [Claims] 1. A hollow portion in one hollow portion having a change in cross-sectional area in a fiber axis direction and a thickness ratio of 1.2 to 2.2.
A fiber having a hollow portion having a modulus of 10 to 40% , a radius of curvature of a vertex in the cross section of the fiber satisfies the following range, and a variation rate of a side portion between adjacent vertices is 1
Polyester fiber characterized by having a polygon of not less than 0% and not less than a triangle and not more than a hexagon. r ≦ d ^0.5 r: radius of curvature at the apex of fiber cross section (μm) d: single fiber fineness (denier) 2. An outer layer component comprising polyethylene terephthalate having an intrinsic viscosity [η] of at least 0.34 and copolymerizing at least 1.5 mol% of 5-sodium sulfoisophthalic acid component,
A polyethylene terephthalate having an intrinsic viscosity [η] of 0.70 or more and a melt viscosity of 1.2 to 6 times the outer layer component as an inner layer component, and a composite ratio of an inner layer portion of 40 to 75% by weight. The laminar composite flow is discharged from an annular base hole composed of three or more and six or less slits,
Polyester characterized by joining a polymer composite stream immediately below a base and stretching a hollow cross-section composite fiber at a draw ratio in the following range, and then eluting an outer layer component with a solvent to form a polygonal hollow cross section. Fiber manufacturing method. Stretching ratio = 1 + (constant tension elongation area elongation × K) / 100 0.6 ≦ K ≦ 1.2