JP2000034641A - Polyamide-based yarn fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material for clothing and a product having excellent process stability in a spinning process and an after-processing process, showing a natural wood appearance by thickness and thinness irregularity in dyeing, providing a dry and smooth touch due to fine unevenness on the surface and excellent fastness to dyeing. SOLUTION: This yarn fabric comprises a multifilament constituted of monofilaments having a change in cross-section area in the fiber axis direction. The multifilament constituting a yarn fabric has 2-20% Uster irregularity by a normal test and >=10 peaks/m U% variation number. The multifilament has difference in cross-section area among the monofilaments in the direction of the cross section of the multifilament and has >=1.2 the maximum value of the thickness and thinness ratio in the direction of the cross section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry and smooth texture with a small difference in shading and color due to thick and thin spots.
The present invention provides a polyamide fiber fabric having a natural heather-like appearance, and is a material that can be widely used especially for sports outerwear, skiing, shirting, and the like.

[0002]

2. Description of the Related Art Conventionally, polyamide fiber fabrics have been used not only for clothing but also for various fields such as industrial use and interior use due to their excellent fabric properties. However, the fabrics made of polyamide fibers such as nylon 6, 66 and the like had poor dry feeling and smooth feel as compared with fiber fabrics made of natural fibers such as silk and hemp.

[0003] Means for imparting a dry feeling to polyamide fibers include deforming the fiber cross section, modifying the polymer,
Various attempts have been made, such as adding particles to a polymer, and in recent years, a method of giving a dry and mottled feel to a fabric by giving a fineness in the fiber axis direction has been studied. However, polyester fiber fabrics represented by polyethylene terephthalate are all commercialized.

Japanese Patent Publication No. 22576/1972 and Japanese Patent Publication No. 44/1988 discloses a method for imparting thickness with polyamide fibers.
No. 7744, a method of generating melt fracture utilizing abnormal flow in a spinneret,
No. 15573, JP-A-55-122017,
Japanese Patent Application Laid-Open No. 58-362107 discloses a method of spinning a mixture of different kinds of polymers. However, any of these methods is liable to cause yarn breakage, resulting in unstable yarn production and poor productivity.

Further, Japanese Patent Application Laid-Open No. Sho 62-191510,
Japanese Patent Application Laid-Open No. 63-21335 discloses a polyamide-based thick and thin yarn whose cross-sectional area fluctuates in the fiber axis direction.
These thick and thin yarns only have a long and thin cycle length of several tens of centimeters in the longitudinal direction of the yarn. When formed into a fiber fabric, they lack dryness. Since the degree of heat setting was increased, the heat setting property in the high-order processing step was poor.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a polyamide fiber which has a small difference in shades of color due to dyeing, has a natural spot feeling, and has a fine unevenness on the surface of the fabric to give a dry and smooth texture. It is intended to obtain a fabric.

[0007]

In order to solve the above-mentioned problems, the polyamide fiber cloth of the present invention mainly has the following constitution. That is, a fabric made of a multifilament composed of a single fiber having a change in cross-sectional area in the fiber axis direction, wherein the wool spots of the multifilament constituting the fabric are 2 to 20% in a normal test, and a U% fluctuation peak. The number is 10 / m or more, and the cross-sectional area differs between single fibers in the cross-sectional direction of the multifilament,
A polyamide fiber cloth, wherein the maximum value of the thickness ratio in the cross-sectional direction is 1.2 or more.

The method for producing a polyamide fiber fabric of the present invention mainly has the following constitution. That is, the polyamide multifilament undrawn yarn obtained by melt spinning,
Stretch false twisting under the conditions of a stretching ratio and a heat setting temperature of 50 to 200 ° C. as shown in the following formula, and is substantially non-crimpable and has a crystallinity of 35%.
After obtaining a polyamide-based thick and thin yarn of less than 1, the fabric is heat-set at 160 ° C. or higher in a pre-dyeing process, and the crystallinity of the multifilament constituting the fabric is adjusted to 35% or higher.
This is a method for producing a polyamide fiber cloth, which is characterized by dyeing. Stretching ratio = 1 + (constant tension elongation area elongation × K) / 100 0.6 ≦ K ≦ 1.6

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The multifilament constituting the polyamide fiber fabric of the present invention has a worst spot in the length direction of 2 to 20% in a normal test. If the Worcester spots are less than 2% in a normal test, the appearance when dyed is a uniform synthetic fiber unique to spots, and the dry feeling, which is the object of the present invention,
Smooth texture does not appear. On the other hand, if the worcester spots exceed 20% in the normal test, the difference in shades of light and shade when the dyed fabric is used is excessively emphasized. In order to further provide a dry and smooth texture, the value of Worcester spots is preferably 3 to 15%, more preferably 5 to 12%.

Furthermore, it is essential that the number of U% fluctuation peaks when the Wooster spot is measured by a normal test is 10 or more per 1 m of yarn length in order to realize the target texture of the present invention. Here, the number of U% fluctuation peaks is U%
The magnitude of each peak in the chart is read as the difference between the upper and lower ends of the peak, and the difference is a value obtained by counting the peaks of 6% or more. The higher the number of U% fluctuation peaks, the thicker and thinner the thinner pitch is, so that the effect of the neck (constriction) existing at the boundary between the thick portion and the fine portion gives a dry and smooth texture. The number of U% fluctuation peaks is preferably at least 12 / m, more preferably at least 15 / m.

Further, the cross-sectional area of the multifilament constituting the polyamide fiber fabric of the present invention varies between single fibers in the cross-sectional direction. As with conventional thick and thin yarn, if there is no thick and thin in the cross-sectional direction but only in the longitudinal direction of the yarn, the thick and thin as a multifilament becomes large, and the color difference when dyed fabric is used Too much emphasis.

The multifilament constituting the polyamide fiber fabric of the present invention has a maximum thickness ratio of 1.2 or more in the cross-sectional direction. When the maximum value of the thickness ratio is less than 1.2, the surface unevenness effect due to the thickness is hardly exhibited, and the dry and smooth feeling desired by the present invention is not exhibited. In addition,
The thin-to-fine ratio between single fibers in the cross-sectional direction in the present invention is the ratio of the cross-sectional area of a thick single fiber to a thin single fiber in the cross-sectional direction (cross-sectional area of a thick single fiber / cross-sectional area of a thin single fiber). Yes, a cross section is photographed using an optical microscope every 10 cm in the length direction of the multifilament, and the cross section is calculated by the area ratio of the cross section of the thick single fiber to the thin single fiber in each cross section. In addition, the maximum value of the thickness ratio between the single fibers in the cross section direction is the ratio of the cross-sectional area of the thickest single fiber to the thinnest single fiber (the thickest single fiber) among all the single fibers constituting the cross section. Fiber / finest single fiber).

The multifilament constituting the polyamide fiber fabric of the present invention preferably has a crystallinity of 35% or more. As in the present invention, in the case of a polyamide-based thick and thin yarn that is stretched in the vicinity of the natural stretching ratio, the fastness of the dyed product is likely to be low because the fiber structure of the thick fineness portion is loose, and the dyeing fastness is high. It is not possible to expand into fields that require a degree. Therefore, it is necessary to heat-set the polyamide-based fiber cloth at a high temperature before dyeing it to densify the fiber structure of the multifilament constituting the fiber cloth and increase the fixing level of the dye. The crystallinity is one of the indices indicating the denseness of the fiber structure, and the higher the crystallinity, the denser the fiber structure, and the higher the crystallinity, the higher the color fastness.

In the present invention, the crystallinity was determined by the following equation by measuring the yarn density by a density gradient tube method. Abbreviations in the following formula are as follows. Xc: crystallinity (%), d:
Measured yarn density (g / cm ³ ), dc: density of complete crystal part (g / c
m ³ ), da: density of completely amorphous portion (g / cm ³ ) Xc [%] = {dc × (d−da)} /｝ d × (dc
−da)｝ × 100 Here, in the case of nylon 6, dc: 1.23 g / cm ³ , da: 1.0
9 g / cm ³ , dc for nylon 66: 1.24 g / cm ³ , da:
Use 1.09 g / cm ³ .

The main component of the polyamide fiber fabric of the present invention is not particularly limited as long as it is polyamide, but nylon 6 and nylon 66 are preferred in view of fiber forming ability and mechanical properties. The polyamide-based fiber fabric of the present invention also includes sodium polyacrylate, poly (N-vinylpyrrolidone), polyacrylic acid and its copolymer, polymethacrylic acid and its copolymer, polyvinyl alcohol and its copolymer, A moisture-absorbing / water-absorbing substance such as a polyethylene oxide-based polymer or a general-purpose thermoplastic resin such as polyamide, polyester, or polyolefin may be contained within a range not to impair the object of the present invention. Further, in addition to pigments such as titanium oxide and carbon black, conventionally known antioxidants, coloring inhibitors, light stabilizers, antistatic agents, and the like may be contained as long as the object of the present invention is not impaired.

The cross-sectional shape of the multifilament constituting the polyamide fiber fabric of the present invention may be a round cross-section, a triangular cross-section, a multi-lobal cross-section, a flat cross-section, an H-shaped cross-section, a π-shaped cross-section, a C-shaped cross-section, or other known deformed shapes. It may be a cross section. Among them, 3-8 in terms of silky texture, gloss and high water absorption
A multi-lobal cross section having a degree of irregularity of 1.3 or more and having the same number of concave portions and convex parts is preferable, and a degree of irregularity of 1.6 or more is more preferable. Here, the degree of irregularity is, as shown in FIG. 1, a radius ratio R1 / R of a circumscribed circle R1 of an irregular cross section and an inscribed circle R2.
Say 2. Further, a hollow portion may be provided inside the fiber.
Further, a cross-section mixed multifilament obtained by mixing two or more types of irregular cross sections may be used.

The form of the fabric can be appropriately selected depending on the purpose, such as a woven fabric, a knitted fabric, or a nonwoven fabric. However, in order to effectively produce thick and thin surface irregularities, the fabric is preferably used. Further, the fabric of the present invention may be subjected to a water-repellent treatment.
The water-repellent agent and the water-repellent processing method are not particularly limited, and conventionally known processing agents and processing methods can be used.

Next, an example of the method for producing the polyamide fiber fabric of the present invention will be described with reference to FIG.

First, an undrawn yarn is obtained by a melt spinning method,
Once wound into package 1. When the yarn released from the package 1 is stretched at a low magnification between the supply roller 2 and the stretching roller 5, the fluid swirling nozzle 3 for false twisting is installed in the stretching zone, and the articulated balloon is attached to the running yarn. generate. At this time, the temperature of the slit heater 4 was set to 50 to 200.
Heat to ° C. By the combination of the balloon generated by the swirl nozzle and the heated slit heater,
In the yarn, single fibers are separately drawn, and furthermore, a thin pitch yarn having a short pitch, which cannot be achieved by the prior art, is formed by the vibration of the balloon. In other words, the articulated balloon has an effect of eliminating large and thin portions having a long cycle length, and finely dispersing the thick portion and details in the length direction and the cross-sectional direction of the multifilament by the balloon vibration. As described above, since the thick part and the details of the multifilament are mixed and dispersed at a short pitch, the fabric appearance after dyeing gives a natural spot feeling.

FIG. 3 shows a method for obtaining a thick and thin yarn by directly spinning and drawing a melt-spun undrawn yarn without winding it once. After applying an oil agent to the melt-spun undrawn yarn 7 by an oil supply device 8, a fluid swirling nozzle 10 is installed between the first godet roller 9 and the second godet roller 12 to generate a knotted balloon on the running yarn. The film is stretched at a low magnification on the heated slit heater 11 to produce a thick and thin yarn.

In the above-mentioned production method, it is necessary to set the stretching ratio in the following range in order to form an appropriate thick and thin object of the present invention.

Stretching ratio = 1 + (constant tension elongation area elongation × K) / 100 0.6 ≦ K ≦ 1.6 Here, if the coefficient K is less than 0.6, low orientation unstretched Due to the presence of many parts, when dyeing a fiber fabric, most of the deeply dyed parts are occupied, and the natural color tone intended for the present invention cannot be obtained. On the other hand, if the coefficient K exceeds 1.6, the thickness ratio becomes small, resulting in a lack of dryness and dryness. The above-described constant tension elongation region elongation is a value measured by a low-speed tensile tester, and is a value from the measurement start point (a) to the point (b) where necking elongation is completed in the tension-elongation curve of FIG. Indicates the elongation (%).

The heat setting temperature is not clearly defined because the heat history varies depending on the shape of the heater to be used and the like. However, in the case of a heat roll or a hot plate in which the yarn is completely in contact with the heating element, the heat setting temperature is 50 to 50%. 150 ° C, a slightly higher 100 to 2 for non-contact type heaters such as slit heaters
By setting the temperature to 00 ° C., it is possible to form a thin film with a short pitch while suppressing an increase in crystallinity. Further, in the production method of the present invention, the crystallinity at the stage of producing the raw yarn is 3
It is necessary to keep the crystallinity to less than 5% and to increase the crystallinity to 35% or more in the heat-setting step before dyeing after fabricating. That is, in the polyamide-based fiber fabric that is more easily wrinkled, the heat setting property in the high-order processing greatly affects the quality of the final product thereafter. Therefore, in the raw yarn stage, prepare a greige machine with a low degree of crystallinity and good heat setting properties, and remove the wrinkles by heat setting before dyeing and increase the degree of crystallinity to dye with high quality. A fabric having good fastness can be obtained.

The heat setting temperature in the high-order process is determined by a balance between the color fastness of the obtained fabric (the higher the setting temperature, the better) and the yellowing of the product (the lower the setting temperature, the better). It is necessary that the temperature be 160 ° C. or higher in order to bring the temperature to a practical level.

In the present invention, after dyeing with an acid dye or the like, a fixing treatment may be performed using a dye fixing agent such as tannic acid. It is preferable to perform a soaping treatment for removing unfixed dyes. The soaping treatment in the present invention refers to a treatment for removing unfixed dyes or dyes which have been dyed with a weak bonding force and easily fall off after dyeing, and dyed with some unfixed dyes or a weak bonding force. This is different from the fix treatment in which the dyes contained in the fibers are confined. The soaping treatment is pH 6-13, and furthermore p
It is preferable to carry out with H8 to H13 since unfixed dyes can be removed and the fastness is improved. By adjusting the pH to 6 or more, it is possible to prevent a decrease in wet fastness, and to adjust the pH to 13 or less, it is possible to prevent the occurrence of discoloration. Also,
Another advantage of the soaping process is that the fiber structure has a good tactile sensation. In the case of the fix treatment, the dye fixing agent is fixed on the surface of the fibrous structure, so that a sticky feeling due to the effect of the dye fixing agent is produced. On the other hand, in the soaping treatment, the drug does not remain on the surface of the fibrous structure, so that the fiber has a dry and smooth touch inherent to the fiber.

[0026]

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. 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 to the completion of necking elongation was measured.

B. Worcester spots (Normal test) The unevenness of the thickness of the multifilament in the longitudinal direction of the yarn is determined by Uster Tester manufactured by Zellbeger Worcester Co., Ltd.
It was measured with R MONITOR C. The measurement conditions were as follows: yarn speed 8 m / min, twist: S1.5, yarn tension: 1.5, measurement time: 1 minute, measurement mode was normal and average deviation rate (U
%) Was measured.

C. Number of U% fluctuation peaks From the Worcester spot chart measured in section B, read the size of each peak of a fine pattern corresponding to a yarn length of 8 m as the difference between the upper end and the lower end of the peak, and the difference is 6% or more. And the number of peaks per 1 m was calculated.

D. Thickness ratio between single fibers in the cross section direction of the multifilament.
Photographs of the cross section were taken at five locations for each cm, and calculated by the following formula from the cross sectional area of the thick single fiber and the thin single fiber of each cross section.

E. Thickness ratio = cross sectional area of thick single fiber / cross sectional area of thin single fiber Crystallinity Measured according to the density gradient tube method of JIS L 1013 (Test method for chemical fiber filament yarn) 7.14.2. Note that tetrachloroethylene was used as the heavy liquid and toluene was used as the light liquid in the gradient tube. The crystallinity was determined by the following equation. Abbreviations in the following formula are as follows. Xc: crystallinity (%), d: measured yarn density, dc: density of complete crystal part, d
a: Density of completely amorphous part Xc [%] = {dc × (d−da)} / ｛d × (dc
−da)｝ × 100 Here, in the case of nylon 6, dc: 1.23 g / cm ³ , da: 1.0
9 g / cm ³ , dc for nylon 66: 1.24 g / cm ³ , da:
1.09 g / cm ³ was used.

F. Light fastness The light fastness was measured according to the method described in JIS L 0842 (dye fastness test method). The 10-hour irradiation was graded 3, the 20-hour irradiation was graded 4, and the 40-hour irradiation was graded 5. The fading of the sample was judged by the gray scale based on the fading of the blue scale.

G. Washing fastness JIS L 0844 (Dye fastness test method) A-2
After the treatment in accordance with the method described in 1 above, the degree of fading before and after washing was graded by gray scale according to the following criteria.

Grade 5: No fading is observed.

Grade 4: Almost no fading.

Grade 3: Slight fading is observed.

Second grade: Discoloration is observed.

Grade 1: Discoloration is severe.

Example 1 Relative viscosity ηr in sulfuric acid was 2.
70 nylon 6 polymer was melt spun at a spinning temperature of 260 ° C. and a spinning speed of 800 m / min to 200 dtex, 24
An undrawn yarn of three-filament cross section of filament was obtained. The elongation in the constant tension elongation region of this undrawn yarn was 100%, and the irregularity of the fiber cross section was 1.6. The undrawn yarn was fed to the drawing device shown in FIG.
At a fluid swirling nozzle pressure of 0.2 MPa, a 30 cm slit heater temperature of 140 ° C., and a stretching roller speed of 600 m / min (drawing ratio of 2 times, coefficient K = 1).
A non-crimpable multifilament having a thickness of 0 dtex and 24 filaments was obtained. Worcester spot (normal test) of the multifilament is 8.5%,
The number of% fluctuation peaks was 21 / m. In addition, the cross-sectional area of the single fiber in the cross-sectional direction of the multifilament is the total number (2
FIG. 5 shows the result of the measurement, and the maximum value of the thickness ratio was 2.0. The density of the multifilament was 1.129 (g / cm ³ ), and the crystallinity was 30.3%.

Next, the multifilament was woven as a warp and a weft, greige set at 180 ° C., refined by a conventional method, and then set at 170 ° C. in the middle. When the multifilament was extracted from the woven fabric after the intermediate setting and the density was measured, it was 1.136 (g / cm ³ ) and the crystallinity was 35.6%. Then use a commercially available acid dye for about 9
After immersion and dyeing at 0 ° C. for 60 minutes, Granup INA-5 manufactured by Sanyo Chemical Co., Ltd .: 5 g / L, sodium carbonate:
A soaping treatment was performed at 80 ° C. for 20 minutes in a chemical solution of 2 g / L, and finished at 170 ° C. to obtain a habutae.

The obtained sample was subjected to a sensory evaluation. As a result, it was found that the surface of the fabric had a natural appearance with a heather, and was a superior product having a dry and smooth feel.
In addition, both light fastness and washing fastness are 4th grade,
The color fastness was also good. Table 1 shows the evaluation results.

In Table 1, "woster spots"
"Worcester spots due to normal test in the length direction of multifilament", "number of fluctuation peaks", "U% fluctuation peak number in the length direction by normal test of multifilament", "thickness ratio" , "Maximum thickness ratio in the cross section direction of the multifilament", "raw / se" in the section of the fabric set, "great machine set temperature", "medium / se" means "intermediate set temperature" In the term of crystallinity, “medium / after” means “the degree of crystallinity of the multifilament after the intermediate setting”.

[0042]

[Table 1] (Examples 2 and 3) The supply roller speed was 235 m /
Min and 370 m / min, and the draw ratio is 2.5
The operation was performed under the same conditions as in Example 1 except that the magnification was 5 times and 1.62 times. The feed roller speed is set to 235 m / min (coefficient K =
The sample of Example 2 set to 1.55) had an appearance closer to plain dyeing as compared with Example 1, and was slightly inferior in dry feeling and dry feeling, but superior to the conventional product.
Further, the supply roller speed was set to 370 m / min (coefficient K = 0.
The sample of Example 3 described as 62) had an appearance in which the difference in density was slightly stronger than that of Example 1, but both the dry feeling and the dry feeling were excellent as in Example 1. . The evaluation results are also shown in Table 1.

(Comparative Examples 1 and 2) The same conditions as in Example 1 were used except that the supply roller speed was set to 215 m / min and 395 m / min, and the stretching ratio was set to 2.79 and 1.52, respectively. Carried out. Supply roller speed is 215m /
The Worcester spot (normal test) of the multifilament of Comparative Example 1, which was determined by the minute (coefficient K = 1.79), was 1.8%. The sample composed of the multifilament was close to solid color dyeing and had a uniform appearance unique to synthetic fiber. In addition, a dry feeling and a dry feeling were hardly exhibited, and the touch was rather slimy. Further, the supply roller speed is set to 395
m / min (coefficient K = 0.52), the multi-filament Worster's spot (normal test) of Comparative Example 2 was 21.
5%. Although the sample made of the multifilament had a dry feeling, the light and dark color difference due to thick and thin was excessively emphasized, and the quality of appearance was inferior. Further, the light fastness was grade 3 and the washing fastness was grade 3-4, which was poor in practicality. The evaluation results are also shown in Table 1.

Comparative Example 3 The temperature of the slit heater was set to 40
The procedure was performed under the same conditions as in Example 2 except that the temperature was changed to ° C.
In the multifilament of Comparative Example 3, the Worster spot (normal test) was 3.5%, and the U% fluctuation peak was 8 / m. Although the sample comprising the multifilament had a difference in shading depending on the thickness, the cycle of shading was long and the appearance quality was inferior. In addition, a dry feeling and a dry feeling were not so much expressed, and the touch was rather slimy.

(Comparative Example 4) A slit heater temperature of 22
The operation was performed under the same conditions as in Example 2 except that the temperature was changed to 0 ° C. The density of the multifilament of Comparative Example 4 was 1.136.
(G / cm ³ ) and the crystallinity was 35.6%. The woven fabric woven using the multifilament had a slightly less dry and smooth feel than that of Example 2. In addition, wrinkles remained on the surface of the woven fabric due to poor heat setting properties in the high-order processing, and the appearance quality was slightly inferior.
The evaluation results are also shown in Table 1.

(Comparative Example 5) The operation was performed under the same conditions as in Example 2 except that the fluid swirl nozzle was removed from the stretching apparatus.
The Worcester spot (normal test) of the multifilament of Comparative Example 5 was 2%. In addition, the maximum value of the thickness ratio of the multifilament in the cross-sectional direction was 1.1. The sample made of the multifilament had a slimy feel as in Comparative Example 1. The evaluation results are also shown in Table 1.

(Comparative Example 6) The operation was performed under the same conditions as in Example 3 except that the fluid swirl nozzle was removed from the stretching apparatus.
The Worcester spot (normal test) of the multifilament of Comparative Example 6 was 22.3%. In the sample of Comparative Example 6, the light and dark color difference due to thick and thin was excessively emphasized, and the appearance quality was inferior. The evaluation results are also shown in Table 1.

(Comparative Example 7) The same procedure as in Example 3 was carried out, except that the greige set and intermediate set temperatures in the higher-order processing were set at 140 ° C. The multifilament was extracted from the woven fabric after the intermediate setting, and the density was measured.
4 (g / cm ³ ), and the crystallinity was 34.1%.
Further, as a result of performing a dyeing process and a soaping process and performing a sensory evaluation, it was a dry and dry hand, but the light fastness was 3 grade, the washing fastness was 3-4 grade,
It was somewhat poorly practical. The evaluation results are also shown in Table 1.

Example 4 The relative viscosity ηr in sulfuric acid was 2.
Spinning was carried out under the same conditions as in Example 1 except that a nylon 66 polymer of No. 70 was melt-spun at a spinning temperature of 290 ° C. The elongation of the undrawn yarn in the constant tension elongation region was 110%, and the irregularity of the fiber cross section was 1.6. The unstretched yarn was subjected to sensory evaluation on a sample that had been drawn false twisted, woven, set, dyed, and post-treated under the same conditions as in Example 1 except that the coefficient K was 0.909. Similarly to the above, the fabric surface exhibited a natural appearance of heather, and was an excellent product having a dry and smooth feel. Further, the light fastness and the washing fastness were all at least 4 grades, and the dyeing fastness was also good.

The evaluation results are shown in Table 1.

Example 5 The post-treatment after dyeing was performed in the same manner as in Example 1 except that the fixing treatment was carried out by immersing in nylon fix 501 (manufactured by Senka Co., Ltd.) 3% owf at 80 ° C. for 20 minutes instead of the soaping treatment. The same conditions were used. The obtained sample was subjected to a sensory evaluation. As a result, the fabric surface had a natural appearance with a mottled feeling as in Example 1, but the dry feeling and the dry feeling were slightly inferior. In addition, the light fastness and the washing fastness were all good at class 4.

[0052]

[Effect of the Invention] Excellent in process stability in the spinning process and high-order processing process, and when dyed, presents a natural heather-like appearance due to large and thin spots, and has a fine unevenness on the surface, making it dry and dry The present invention provides a material and a product for clothing, which provide a soft touch and a good color fastness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a fiber for explaining the degree of heterogeneity of a fiber cross-section preferred in the present invention.

FIG. 2 is a schematic view of an example of a drawing apparatus for producing a multifilament constituting the polyamide fiber fabric of the present invention.

FIG. 3 is a schematic view of an example of a direct spinning and stretching apparatus for producing a multifilament constituting the polyamide fiber fabric of the present invention.

FIG. 4 is a diagram showing a tension-elongation curve of an undrawn yarn for explaining elongation at a constant tension elongation region.

FIG. 5 is a cross-sectional area of all single fibers (24 filaments) in the cross-sectional direction of the multifilament in Example 1.

[Explanation of symbols]

 1: Undrawn yarn package 2: Supply roller 3: Fluid swirl nozzle 4: Slit heater 5: Stretch roller 6: Spinneret 7: Unstretched yarn 8: Lubricator 9: First god roller 10: Fluid swirl nozzle 11 : Slit heater 12: Second god roller

Continued on the front page F term (reference) 4L036 MA06 MA33 PA03 PA15 PA18 RA27 UA01 UA08 UA12 UA30 4L045 AA05 BA03 BA33 CA25 DA08 DA09 DA42 DA44 DC02 4L048 AA24 AA36 AA37 AA47 AB07 AB11 DA01 DA03

Claims (5)

[Claims] 1. A fabric comprising a multifilament composed of a single fiber having a change in cross-sectional area in a fiber axis direction, wherein the wool spot of the multifilament constituting the fabric is 2 to 20% in a normal test, and U % Variation peak number is 10 pieces / m or more, and the cross-sectional area differs between single fibers in the cross section direction of the multifilament, and the maximum value of the thickness ratio in the cross section direction is 1.2 or more. Polyamide fiber cloth. 2. The polyamide fiber fabric according to claim 1, wherein the degree of crystallinity of the multifilament constituting the polyamide fiber fabric is 35% or more. 3. The polyamide fiber fabric according to claim 1, wherein the dye fixing agent does not adhere to the surface of the polyamide fiber cloth.
The polyamide fiber fabric according to the above. 4. A non-stretched polyamide multifilament yarn obtained by melt spinning is false-twisted under the conditions of a draw ratio shown below and a heat setting temperature of 50 to 200 ° C., and is substantially non-crimped and crystallized. After obtaining a polyamide-based thin yarn having a degree of crystallization of less than 35%, the cloth is heat-set at 160 ° C. or higher in a pre-dyeing process to make the degree of crystallization of the multifilaments constituting the cloth 35% or higher. A method for producing a polyamide-based fiber fabric, characterized by dyeing. Stretching ratio = 1 + (constant tension elongation area elongation × K) / 100 0.6 ≦ K ≦ 1.6 5. The method for producing a polyamide fiber fabric according to claim 4, wherein a soaping treatment is performed at a pH of 6 to 13 after the dyeing.