JPH07292523A - Polyester hollow fiber with good shrinkage and gloss - Google Patents

Abstract

(57) [Summary] [Structure] The composition is made of a copolyester in which the copolymerization amount and the intrinsic viscosity (IV) of the high-shrinkability-imparting component are specified, and the fiber has a circular cross section and a hollow portion at the center of the fiber cross section. A polyester hollow fiber having a good shrinkage and gloss with the hollow ratio of the hollow portion and the thickness of the thinnest portion of the hollow portion within a predetermined range. [Effect] The polyester hollow fiber of the present invention is a fiber having excellent shrinkage and gloss which are not present in conventional hollow fibers, being lightweight, excellent in heat retention and repulsion, and having a fiber cross-section that is hard to be crushed. Therefore, the fiber of the present invention is useful as a material for clothing, a material for interior products, an interior material for vehicles, etc., especially when it is compounded or mixed with other fibers having low shrinkage, it has high quality and high quality with bulge and repulsion. Can be a textile product.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hollow polyester fiber having good shrinkability and gloss. More specifically, it is not only suitable as a lightweight material, heat insulating material or light weight / heat insulating material for general clothing and industrial construction, but also has better shrinkability and luster than conventional products, and the fiber cross section is difficult to collapse. , High quality, high quality polyester hollow fiber. In particular, when it is used as a composite or mixed fiber with another fiber having low shrinkage, it can be used as a fiber which can impart not only light weight and heat retention but also resilience.

[0002]

2. Description of the Related Art Polyester fibers are widely used for general clothing and industrial construction due to their excellent properties such as mechanical properties, chemical properties, easy care and gloss. In particular, recently, a unique product which is not found in other fibers has been developed by applying the excellent properties of polyester fiber. In addition, diversifying consumer needs and needs for individualized sensibilities, various performances of higher quality such as lighter weight products, textile products with more heat-retaining function or products with better texture Is required.

Most of the high-quality polyester fiber products in recent years are not only a single type of fiber yarn to be used but also a so-called composite or mixture of two or more types of fibers having different characteristics. In many cases, a composite yarn or a mixed fiber is used, and various techniques such as a mixed fiber of different fineness, a mixed fiber of different shapes, and a mixed fiber of different shrinkage have been proposed. Many techniques, such as a mixed yarn of different fineness and different shape, have been proposed by combining these. Among these, many techniques for combination with different shrinkage mixed yarn have been proposed. For example, it is a mixed yarn of different fineness and different shrinkage.

Techniques for the different shrinkage mixed yarns include, for example, Japanese Patent Publication No. 55-22586 and Japanese Patent Laid-Open No. 58-12081.
Japanese Unexamined Patent Publication No. 6 and the like discloses a technique capable of simultaneously imparting swelling, softness, and drapeability to a silky-tone woven or knitted fabric using a different shrinkage mixed yarn. In these techniques, the shrinkage difference between the low shrinkage yarn and the high shrinkage yarn is as large as 40%, and the high shrinkage yarn has a shrinkage ratio considerably higher than that of a normal yarn.

Further, Japanese Patent Application Laid-Open No. 3-59130 and Japanese Patent Application Laid-Open No. 3-64543 disclose techniques of differently contracted mixed yarns, and in these techniques, a group of fibers constituting the differently contracted mixed yarns. There is disclosed a technique of polyester different shrinkage mixed filament yarn suitable for a thin woven or knitted fabric in which a transparent material of the woven or knitted fabric is prevented from being transparent by including a matting agent in all of the above. Even in these techniques, the shrinkage difference between the low shrinkage yarn and the high shrinkage yarn is quite large, and the high shrinkage yarn has a considerably high shrinkage ratio. As mentioned above, there are many disclosures of the technology relating to fibers having high shrinkability.

On the other hand, in order to achieve the weight reduction and heat retention of the polyester fiber product, it is possible to attain a certain level by increasing the bulkiness of the yarn or devising the structure of the woven or knitted fabric. To further reduce the weight, it is necessary to reduce the weight of the fiber itself. As one of the means, it is known to use apparently lightweight hollow fibers. As the hollow fiber, for example, Japanese Examined Patent Publication No. 42-2928.
The publication discloses a method for producing a hollow fiber having a hollow ratio of 50% or less, and many other patent publications disclose a hollow fiber and a method for producing the fiber.

When hollow fibers are used as a component of the above-mentioned different shrinkage mixed yarn, the woven or knitted fabric obtained therefrom is reduced in weight by the amount corresponding to the hollow portions of the hollow fibers, and at the same time, it corresponds to the hollow portions. There is an effect that heat retention is improved by the amount. Moreover, when the hollow fiber is used as the high shrinkage component of the different shrinkage mixed yarn, when the different shrinkage mixed yarn or the woven or knitted fabric is heat-treated, the hollow fiber is more central than the different shrinkage mixed yarn or the woven or knitted fabric. It is possible to manufacture the different shrinkage mixed yarn or the woven or knitted fabric thereof, which is located in the above position and exhibits the resilience of the hollow fiber. Therefore, a polyester hollow fiber imparted with high shrinkability is strongly desired.

However, in addition to such high shrinkage, a polyester hollow fiber of high quality and high quality, which has better luster than that of conventional products, is lightweight and has excellent heat retention, and has a fiber cross-section that is not easily crushed, is produced. The reality is that it has not been obtained yet.

[0009]

DISCLOSURE OF THE INVENTION The object of the present invention is to have better shrinkability and luster than the conventional polyester hollow fibers as described above, to be lightweight and excellent in heat retention, and to have a fiber cross section. To provide a high-quality, high-quality polyester hollow fiber that is hard to be crushed.

[0010]

The above object of the present invention is to form a highly shrinkable component by copolymerization in an amount of 2 to 20 mol% and to form a copolymerized polyester having an intrinsic viscosity (IV) of 0.60 or more. The outer shape of the fiber cross section is circular, and a hollow portion is provided at the center of the fiber cross section. The thickness (NA) of the thinnest portion of the non-hollow portion satisfies the following formula, It can be achieved by a polyester hollow fiber having good shrinkage and gloss characterized by a hollowness of 10 to 50%. NA (micron) ≧ 2.1 × d ^1/2 where NA is the thickness of the thinnest part in the non-hollow part (micron) d is the fineness of the fiber (denier) Hereinafter, the present invention will be described in detail. To do. First, the polyester hollow fiber of the present invention contains 2 to 20 mol% of a high shrinkage imparting component.
It is necessary to copolymerize and form a copolymerized polyester having an intrinsic viscosity (IV) of 0.60 or more.

The copolymerized polyester used in the present invention is obtained by copolymerizing the high shrinkability imparting component in an amount of 2 to 20 mol%, preferably 4 to 17 mol%, as described above. When the copolymerization rate of the high shrinkability-imparting component is less than 2 mol%, the effect of improving the shrinkability is insufficient, and when the copolymerization rate exceeds 20 mol%, the shrinkability becomes sufficiently high, but during melt spinning. The spinnability of No. 1 is remarkably deteriorated, and the hollow fiber is not easily formed in the hollow portion, so that only hollow fibers having irregular cross-sectional shapes can be obtained.

The term "high-shrinkability-imparting component" as used herein means a polyester fiber produced by copolymerizing the high-shrinkability-imparting component into polyester to produce a high-shrinkability-imparting component which has not been copolymerized. Also means a compound exhibiting a high boiling water shrinkage (hereinafter, simply referred to as shrinkage). Specific examples thereof include dicarboxylic acids such as oxalic acid, sebacic acid, phthalic acid, and isophthalic acid, glycols such as diethylene glycol, polyethylene glycol, neopentyl glycol, and bisphenol A.
Examples thereof include ethylene oxide adducts and ethylenoxide adducts of bisphenol sulfone. Of these, isophthalic acid and bisphenol A ethylene oxide adducts are preferable from the viewpoints of price and yarn operability.

These high-shrinkability-imparting components may be used either individually or in combination of two or more. In particular, the above-mentioned isophthalic acid and bisphenol A ethylene oxide adduct are preferably used in combination. At that time, isophthalic acid and bisphenol A
When the former is used in an amount of 3 mol% or more and the latter is used in an amount of 1 mol% or more, the soft feeling of the fiber product can be further improved.

The copolyester used in the present invention has an intrinsic viscosity (IV) of 0.60 or more, preferably 0.6.
3-0.9 is required. Intrinsic viscosity (IV) is 0.60
If it is less than the above value, the hollow fiber is not formed in a hollow portion at the time of melt spinning, and the cross-sectional shape of the fiber becomes uneven.
In addition, the strength and elongation of the fiber are lowered, and yarn breakage frequently occurs in the fiber manufacturing process, and troubles such as fluff generation and yarn breakage frequently occur in the fiber product manufacturing process.

In the copolymerized polyester used in the present invention, if a large amount of matting agent is contained, it becomes difficult to obtain fibers having good gloss. Therefore, the amount of the matting agent in the polyester is preferably 0.1% by weight or less, more preferably 0.07% by weight or less, most preferably 0.05% by weight or less.
Further, the copolyester as referred to herein is a copolyethylene terephthalate based on polyethylene terephthalate.

Next, the polyester hollow fiber of the present invention is required to have a circular fiber cross section. That is, if the outer shape of the fiber cross section is extremely irregular, yarn breakage frequently occurs during spinning, and yarn breakage or fluffing often occurs during drawing. It is most preferable that the circular shape here is a perfect circle, but it does not necessarily have to be a perfect circle as long as it is a substantially perfect circle. Specifically, the diameter of a circle or an ellipse varies within 10% between the long diameter and the short diameter, or the distance R ₁ to the point on the outer periphery farthest from the yarn center of gravity and the outer periphery closest to the yarn center of gravity. The relationship of the distance R ₂ to the upper point is [(R ₁ −
R ₂ ) / R ₁ ] × 100 ≦ 10 may be satisfied.

Further, the polyester hollow fiber of the present invention must have a hollow portion, preferably a triangular hollow portion, at the center of the fiber cross section. That is, the fact that the hollow portion of the fiber cross section is at the center means that the hollow portion is not substantially eccentric. The presence of the hollow portion allows the weight of the fiber to be reduced, and the weight of the woven or knitted fabric can be reduced accordingly. Also, good gloss can be obtained by forming the hollow portion into a triangular hollow fiber. The reason why good gloss is obtained is not clear, but when the hollow fiber is exposed to light, the content of the delusterant usually remains small, so most of the light enters the hollow part, and the light It is considered that the inner wall of the triangular hollow portion again reflects the light to enhance the gloss, and that it exhibits good gloss. Furthermore, because the hollow part is in the center of the fiber and the hollow part is triangular,
Crushing of the hollow portion, that is, reduction of the hollow ratio during stretching and the high-order processing step is reduced. Generally, in the production of hollow fibers and their higher-order processing steps, hollow fibers are subjected to lateral pressure on the fibers due to the yarn contact pressure with rollers, frictional force in guides, or other external force It collapses into an elliptical shape or a flat shape, and the hollow rate comes to decrease. This phenomenon is more likely to occur in hollow fibers having a higher hollow ratio. Moreover,
If the hollow ratio exceeds a certain level, it tends to occur when the outer shape of the fiber and the hollow portion are circular. In addition, if the hollow portions are unevenly distributed in the center of the fiber, that is, if the hollow portions are partially present, it tends to occur. On the other hand, the polyester hollow fiber of the present invention has a hollow portion at the center of the fiber cross section as described above, and thus is difficult to be crushed.

A triangular shape as a preferable shape of the hollow portion of the polyester hollow fiber of the present invention will be described with reference to FIG. FIG. 1 is a view for explaining the shape of the hollow portion of the polyester hollow fiber of the present invention. That is,
The three triangular vertices of the hollow portion of the hollow fiber are defined as a, b, and c, and the three sides of the triangle connecting the three points with straight lines are defined as ab, bc, and ca. A perpendicular line cd is drawn from the point c to the side ab, and an intersection point with the hollow wall on the extension of the perpendicular line cd is defined as e. Sides bc and c from points a and b, respectively
A perpendicular line is also drawn on a, and points f, g, h,
Determine point i. The hollow hollow portion of the polyester hollow fiber of the present invention preferably has a triangular shape, more preferably an equilateral triangular shape, but may have a rice ball shape as shown in FIG. The preferable shape of the hollow portion is summarized as follows. (1) The lengths of the line segments ab, bc, and ca on the sides are preferably equal, but may change within 20%. (2) The respective values of the line segment ag / line segment af, the line segment bi / line segment bh, and the line segment ce / line segment cd are preferably 1.0 to
1.3, and more preferably 1.0 to 1.2.

In the polyester hollow fiber of the present invention, the area occupied by the hollow portion in the fiber cross section, that is, the hollow rate of the fiber must be within the range of 10 to 50%. Hollow rate is 10%
When the amount is less than the above, the effect of reducing the weight of clothing is small, and the heat retaining effect is also small. The warmth of the woven or knitted fabric can be increased to some extent by using a structure that contains air between fibers or tissues as described above, but if a structure that contains too much air is used, the air warmed by body temperature causes convection. It raises, and heat retention falls. Since the hollow fiber encloses air in the fiber itself, there is no convection and heat retention can be improved. The higher the hollow rate, the greater the effect of weight saving and heat retention of the fiber product, which is preferable.However, if the hollow rate is too high, the fiber cross section is likely to be crushed in the high-order processing process, and it is not suitable for clothing. Since the hollowness of the yarn cannot be maintained and the fiber cross section is crushed even when the clothing is worn, the hollowness needs to be 50% or less. The hollow ratio is preferably 15 to 40% from the viewpoints of the effect of reducing the weight, the effect of keeping heat, and the crushability of the fiber cross section during wearing.

Further, in the polyester hollow fiber of the present invention, it is necessary that the thickness (NA) of the thinnest part in the non-hollow part in the fiber cross section satisfies the following expression. NA (micron) ≧ 2.1 × d ^1/2 However, NA is the thickness of the thinnest part in the thickness of the non-hollow part (micron) d is the fineness of the fiber (denier) For example, in the case of 3 denier fiber, It is necessary to set the NA to 3.6 microns or more. The wall thickness referred to here is the length of the fiber upper portion in the line segment connecting the center of gravity of the hollow fiber and the fiber surface. The wall thickness of the non-hollow portion is determined by the fineness of the hollow fiber, the hollow ratio, and the shape of the hollow portion. In any case, it is essential that the wall thickness satisfies the above formula in order to prevent the collapse of the fiber cross section. is there.

Further, the polyester hollow fiber of the present invention preferably has a shrinkage of 15% or more, but if the shrinkage is too high, the woven or knitted fabric is likely to become coarse and hard.
It is better to be less than or equal to%. Furthermore, in the polyester hollow fiber of the present invention, the presence or absence of fluff in the raw yarn stage, that is, the presence or absence of fluff in the yarn that is spun, drawn and wound, is greatly related to the quality of the higher-order processability, and its influence is not Larger than polyester fiber. Therefore, the number of fluffs of the wound thread is 0.
20co / 10 ⁴ m or less is preferable, 0.10co / 10 ⁴
m or less is more preferable, and 0.05 co / 10 ⁴ m or less is most preferable.

Next, a production example of the polyester hollow fiber of the present invention will be described. That is, FIG. 2a is a cross-sectional example of the discharge hole of the spinneret for polyester hollow fibers of the present invention, and FIGS. 2b to 2d are cross-sectional examples of the discharge holes of conventionally known spinnerets for polyester hollow fibers. 3a is an example of a fiber cross section spun from the discharge hole of the hollow fiber spinneret of FIG. 2a, and is an example of a fiber cross section spun from the discharge hole of the hollow fiber spinneret of FIGS. 3b-d. is there.

The polyester hollow fiber of the present invention is a copolyester obtained by adding, for example, 10.0 mol% of isophthalic acid as a high shrinkage imparting component in the polyester polymerization step (direct polymerization) (the content of the matting agent is Is, for example, 0.05
2% by weight) is melt-spun from a spinneret having three slit type polymer discharge holes as shown in FIG. 2a,
It can be obtained by applying an oil agent to obtain an unstretched yarn, winding the yarn once, or subsequently stretching it. At this time, forcible cooling of the melt-spun yarn is carried out under the spinneret surface 3-1.
It is preferable to start blowing the cooling air at a distance of 5 cm in order to reduce the variation in hollow ratio. Further, at the time of stretching, using a hot roll-hot roll type stretching machine, preheating to 75 to 100 ° C. with the first hot roll,
A method of stretching with the second hot roll is preferable in order to reduce generation of fluff. The temperature of the second hot roll may be appropriately set so as to match the target shrinkage characteristic of the yarn to be obtained. The cross-sectional shape of the resulting fiber is similar to that shown in Figure 3a.

As described above, the hollow polyester fiber of the present invention is a hollow fiber having a specific cross-sectional shape of the fiber, which is obtained by copolymerizing a high shrinkability-imparting component in a specific amount and having an intrinsic viscosity of a predetermined value or more. By using a fiber, it is possible to provide a high-quality polyester hollow fiber having good shrinkability and gloss not required for conventional hollow fibers, being lightweight and excellent in heat retention, and having a fiber cross section that is not easily crushed. it can. Further, the polyester hollow fiber of the present invention can be sufficiently used alone in a woven or knitted fabric, but when other fibers are used as a low shrinkage yarn in a composite or mixed fiber, swelling and repulsion are imparted. From the viewpoint, it is particularly preferable and effective. When composited or mixed, the difference in shrinkage value between the high shrinkage yarn and the low shrinkage yarn is preferably at least 5% or more, more preferably 8% or more. In addition,
The mixed yarn in the present invention means a yarn obtained by using two or more kinds of fibers by using a known mixing treatment device, and the composite yarn means a yarn obtained by not mixing two or more kinds of fibers. Refers to the article.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples. The physical properties in this example were measured as follows. A. Shrinkage rate After measuring the sample length (L ₀ ) under a load of 0.1 g / d, the yarn is subjected to boiling water treatment for 15 minutes under no load and without tension. After the boiling water treatment, the sample length (L ₁ ) was measured under a load of 0.1 g / d and calculated by the following formula. Shrinkage rate = ((L ₀ −L ₁ ) / L ₀ ) × 100 (%) B. Hollow ratio Calculated by the following formula from a cross-sectional photograph of the fiber. Hollow ratio (%) = (Cross-sectional area of hollow part / Cross-sectional area of fiber) × 1
00 C. Intrinsic viscosity (IV) Dissolve 0.8 g of a sufficiently dried sample by washing thoroughly to remove oils and the like, and dissolving in 10 c.c of orthochlorophenol,
It measured at 25 degreeC with the Ostwald viscometer. D. Glossiness Using an automatic colorimetric color difference meter manufactured by Suga Test Instruments, the standard value was adjusted using a magnesium oxide standard gloss board under the conditions of irradiation 45 degrees and light reception 44 degrees, and then the fiber was applied to the sample yarn wound on the aluminum plate. The glossiness was measured by irradiating and receiving light in the axial direction. E. Using a multi-fly counter type F of Toray Engineering Co., Ltd., 5 drawn fibers were run at a speed of about 400 m / min to measure 5 × 10 ⁴ m each, and the number of fluff was calculated from the total number counted. Number of fluffs (co / 10 ⁴ m) = (total number of counts / 25 × 10
⁴ m) × 10,000 Example 1 7 levels of copolyester obtained by changing the copolymerization rate (mol%) in the polyester production step (direct polymerization) of the high shrinkage imparting component (dioxide as a matting agent (Titanium content is 0.05% by weight), the spinning temperature was 285 ° C., and a spinneret having 24 discharge holes as shown in FIG. After cooling by applying cooling air at a constant speed, the smoothing-providing oil agent was applied while controlling the oil content to be 1.2% by weight, and then wound at a spinning speed of 1650 m / min. The intrinsic viscosity of each level of copolyester is approximately 0.65 (0.61
.About.0.63).

The obtained undrawn yarn is preheated by a hot roll-hot roll type drawing machine with the first hot roll set to 88 ° C., and the drawn yarn elongation is 35 ± 2 with the second hot roll. %, While heat-treated at a second hot roll temperature of 120 ° C while stretching at a draw ratio of 800%, and a winding speed of 800 m / min.
It was wound up with a hollow fiber filament of 75 denier 24 filaments. The cross section of the obtained fiber is almost the same as that of FIG. 3a, and the hollow portion is triangular and the center portion of the fiber is present. The thinnest portion of the non-hollow portion has a thickness (NA) of 4.6 microns. It was The number of fluffs of the obtained fiber yarn was 0.10 co / 10 ⁴ m or less at all levels. The hollow ratio of those fibers is in the range of 20 to 23%. Table 1 shows the evaluation results of the glossiness and shrinkage of the fiber.

[0027]

[Table 1] As is clear from Table 1, the experiment No. The fibers of Nos. 3 to 8 (product of the present invention) had a good glossiness of 70% or more, and the shrinkage ratio thereof was also No.
The level of shrinkage was several percent or more higher than that of No. 1 (comparative product), which was good. In addition, the experiment No. No. 6 (invention product) was a copolymer of isophthalic acid and an ethylene oxide adduct of bisphenol A as a component for imparting high shrinkage, and this yarn and the knitted fabric were copolymerized with 10 mol% of isophthalic acid. Experiment No. It was much richer in softness than that of No. 5 (the product of the present invention). Experiment No. 1
The fiber of (Comparative product) had a poor shrinkage rate and was poor because it did not copolymerize the high shrinkability imparting component. Experiment No. Two
The fiber of (Comparative product) had a low shrinkage rate and was unsatisfactory because the amount of the high shrinkage imparting component was small. Experiment No. The fiber of No. 9 (comparative product) has a large amount of the high shrinkage imparting component, so that the hollow part forming property during melt spinning is poor and the fiber cross-sectional shape is not uniform, and the spinnability and drawability are remarkably inferior. Not only that, but the gloss of the fiber was also low.

Example 2 Example 1, Experiment No. According to Example 1, except that the polymer of No. 6 was used and the inner diameter of the slit arranged in a ring shape at the die discharge hole of Fig. 2a was changed, a hollow fiber yarn with a changed hollow ratio was obtained. It was The number of fluffs of the obtained yarn is 0.
Were less than 10 U / 10 ⁴ m. Further, the thinnest part of the non-hollow part has a wall thickness (NA) of 3.4 to 6.0.
It was the thinnest in the micron range (Experiment No. 13; 3.7 microns, Experiment No. 14; 3.4 microns). Table 2 shows the results of evaluation of the obtained hollow fiber yarn and the knitted tubular knitted fabric according to Example 1.

[0029]

[Table 2] In Table 2, the experiment No. The knitted fabric of No. 10 (comparative product) had a small hollow ratio and thus had a small effect of lightness, which was not much different from that of the ordinary round cross-section yarn. Experiment No. In the knitted fabric of No. 14 (comparative product), the fibers were often crushed during knitting, and the hollow ratio in the knitted fabric was small. The thickness of the thinnest portion in thickness of the portion not hollow section (NA) ^{is, 2.1 × 3 1/2 =} 3.6
It was less than (micron), and the fibers were often crushed and the crushing degree was large. The shrinkage rate was good at 17% or more at each level. Furthermore, in terms of lightweight and maintaining the shape of the fiber cross-section during post-processing, Experiment No. The fibers of 11, 12, and 13 (all of the present invention) are excellent and can be effectively used as various fiber products.

Example 3 Example 1, Experiment No. 2b, 2
Example 1 except that a die having a die discharge hole of c was used.
According to the above, a hollow fiber yarn having a modified fiber cross section was obtained and evaluated. The cross section of the obtained fiber was almost the same as that shown in FIGS. 3b and 3c. The evaluation results are shown in Experiment N of Example 1.
o. The results are shown in Table 3 in comparison with No. 6.

As shown in FIG. 3b, the hollow fiber yarn having a trilobal outer shape in the fiber cross section (Experiment No. 15; comparative product, hollow ratio 15.1%) had 15 yarn breaks during spinning. The amount of fluff generated during drawing was as high as 3.8 k / 10 ⁴ m, and the yarn breakage rate was as high as 13%. The hollow fiber yarn having an eccentric hollow portion as shown in FIG. 3c (Experiment No. 16; comparative product) had a hollow ratio of 20.3%, but the change in cross section was large when knitted, and Crushing occurred and the hollow ratio was reduced to 13.0%.

[0032]

[Table 3] Example 4 Example 1, Experiment No. 2 polymer, using the polymer of FIG.
Using a die having a die discharge hole of d, the hollow rate is about 35.
According to Example 1, except that the content was adjusted to 100%, hollow fiber yarns in which the shapes of the hollow portions of the fibers were compared were obtained and evaluated. The cross section of the resulting fiber was similar to that shown in Figures 3a and 3d. The evaluation results are shown in Table 4.

The hollow fiber yarn (experiment No. 18; comparative product) having a hollow portion having a substantially perfect circular shape as shown in FIG. 3D had a hollow ratio of 36.0%. The change was large and the fibers were crushed, and the hollow ratio was reduced to 26.1%. Further, streak-like unevenness was generated in the crushed portion of the fiber in the knitted fabric, which markedly impaired the quality of the knitted fabric. The hollow fiber yarn (experiment No. 17; product of the present invention) having a substantially hollow shape as shown in FIG. 3a has a hollow ratio of 35.1%, and even if it is a knitted fabric, there is almost no collapse of the fiber and it is hollow. The rate was also 33.7%, and the quality of the woven fabric was extremely good.

[0034]

[Table 4] Example 5 Example 1, Experiment No. Example 1 except that the intrinsic viscosity (IV) was changed by changing the conditions at the time of polymerization with the polyester composition of 6 and the spinning temperature was changed so that melt spinning could be normally performed.
The hollow fiber yarn was obtained and evaluated according to the above. Table 5 shows the evaluation results
It was shown to.

[0035]

[Table 5] Experiment No. 1 having a low intrinsic viscosity (IV). 19 (comparative product) is
Yarn breakage is a lot stretchability also poor during spinning, fluff of the yarn occurs frequently with 3.9 U / 10 ⁴ m. Moreover, the hollow ratio was slightly low. Experiment No. In Nos. 20 to 22 (inventive products), the hollow ratio and the spinnability were good. However, the experiment No. No. 22 had some difficulty in spinning for a long time because of its high melt viscosity during spinning, but there was no problem in production. The shrinkage rate and other characteristics were satisfactory at each level.

[0036]

Industrial Applicability The polyester hollow fiber of the present invention is formed of polyester having an intrinsic viscosity of not less than a predetermined value by copolymerizing a predetermined amount of the high shrinkability-imparting component, and specifies the fiber cross section and hollow part shape. As a result, it is possible to provide a high-quality, high-quality polyester hollow fiber that has good shrinkability and luster that conventional hollow fibers do not have, is lightweight, has excellent heat retention and resilience, and has a fiber cross-section that does not easily collapse. it can. Therefore, the polyester hollow fiber of the present invention is useful as a material for clothing, a material for interior products, a vehicle interior material, and the like. In particular, when it is used as a composite or mixed fiber with other fibers having low shrinkage, it can be a high-quality, high-quality fiber product having bulge and repulsion.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the shape of a hollow portion of a polyester hollow fiber of the present invention.

FIG. 2a is a schematic cross-sectional view showing an example of the discharge hole of the spinneret for polyester hollow fibers of the present invention, and FIG.
2d is a schematic cross-sectional view showing an example of discharge holes of a conventionally known spinneret for polyester hollow fibers.

FIG. 3a is a schematic cross-sectional view of a hollow fiber through a discharge hole of the spinneret for hollow fiber of FIG. 2a, and FIGS. 3b to 3d show hollow fiber through a discharge hole of the spinneret for hollow fiber of FIGS. 2b to 2d. It is a schematic sectional drawing.

[Explanation of symbols]

a: Triangular apex of hollow fiber hollow part b: Triangular apex of hollow fiber hollow part c: Triangular apex of hollow fiber hollow part d: Point with respect to line segment ab of side of the above triangle An intersection of a perpendicular line drawn from c and a line segment ab h: An intersection of a perpendicular line drawn from the point b and a line segment ac with respect to the side line segment ac of the triangle f: A line segment bc of the side of the triangle The intersection of the perpendicular line drawn from the point a and the line segment bc e: The intersection of the extension line of the line segment cd of the above triangle and the side ab g: The intersection of the extension line of the line segment af of the above triangle and the side bc i: The intersection of the extension line of the above-mentioned triangular line segment bh and the side ac

Claims (1)

[Claims] 1. A high-shrinkability-imparting component is copolymerized in an amount of 2 to 20 mol%, and is formed of a copolyester having an intrinsic viscosity (IV) of 0.60 or more, and the cross-section of the fiber is circular and the fiber is It has a hollow part in the center of the cross section, the thinnest part of the non-hollow part has a wall thickness (NA) satisfying the following formula, and the hollow part has a hollowness of 10 to 50%. Polyester hollow fiber with good shrinkage and gloss. NA (micron) ≥ 2.1 x d ^1/2 where NA is the thickness of the thinnest part in the non-hollow part (micron) d is the fineness of the fiber (denier)