JP6627572B2 - Polyamide fiber and fabric comprising the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a polyamide fiber containing a pigment and a fabric using the same.

  Polyamide fibers such as polycapramid and polyhexamethylene adipamide are widely used in clothing and industrial materials because of their excellent mechanical properties, chemical resistance and heat resistance. In particular, due to its excellent strength, abrasion resistance, deep dyeability, and the like, it is used in many garment applications. In recent years, the diversification of fashion and the expansion of applications have been progressing, and there is a demand for a chambray-like fabric with high designability even in innerwear, sportswear, casual wear, and the like.

  As a method of producing a fabric having a chambray feeling, a method of combining a polyamide fiber and a polyester fiber, or a combination of a polyamide fiber dyed with a normal anionic dye and a polyamide fiber dyed with a cationic dye, and dyeing with a different dye is generally used. Is known. However, dyeing with dyes with different dyeing conditions complicates the dyeing process, increases the production cost and increases the environmental load due to the waste dyeing liquor.Therefore, polyamide fibers that exhibit a chambray effect with a single dye are desired. ing. As a method for expressing the chambray feeling with such a single dye, a method using a polyamide fiber containing a pigment in the fiber has been studied. As a polyamide fiber containing a pigment, Patent Document 1 proposes a polyamide spun fiber containing carbon black in the fiber.

  Generally, in order to stabilize the quality of a fabric, the yarn is entangled with the purpose of imparting a bundle property to the yarn in order to prevent the generation of slack and fluff of a single yarn during fabric production. The optimization of the entangled state of the fiber at this time is described in Patent Document 2 and Patent Document 3, in which the polyamide fiber which defines the mutual relation such as the number of entangled portions of the fiber, the length of the entangled portion, and the length of the non-entangled portion is described. Has been proposed.

JP 2015-71839 A JP 2007-126796 A JP 2006-265743 A

  However, the fiber containing the carbon black pigment described in Patent Literature 1 has low friction because the pigment is precipitated on the fiber surface and the fiber surface has irregularities. Therefore, during fiber production, when the fiber is stretched between two rollers, the fiber is likely to slip on the roller, causing poor stretching and partially lacking fiber uniformity. When this fiber is used in a woven fabric, it becomes uneven or streaked, which causes a reduction in product quality. In particular, fibers containing pigments have unevenness and streaks more conspicuous than fibers not containing or containing a very small amount, so that there remains a problem in product quality.

  The entangled state described in Patent Literature 2 is a low friction yarn particularly in the case of a fiber containing a pigment. Therefore, the entanglement is loosened in a state where the yarn is under tension (flying state) during weaving and weaving. Would. That is, since the entanglement retention rate is low, there is a problem that unevenness and streaks occur in the woven fabric.

  Further, in the entanglement method described in Patent Document 3, since strong entanglement is performed before stretching, and particularly in the case of a fiber containing a pigment, the entangled portion has a further low friction. On the other hand, slip tends to occur continuously, causing poor stretching and lacking uniformity of the whole fiber. Therefore, when this fiber is used for a woven fabric, there is a problem that unevenness and streaks are generated.

  Therefore, the present invention is intended to solve the above-mentioned problems, and does not cause defects such as unevenness when fabric is produced, and a polyamide-dipped fiber which can obtain a product quality excellent in uniformity of physical properties. The task is to provide.

The above problem can be solved by the following configuration.
(1) The fineness variation rate is 1.0% or less, the difference between the maximum fineness and the minimum fineness in the fineness variation rate measurement is 10% or less of the average fineness, and the length L1 of the fiber opening portion is 5 to 100 mm. When the dispersion of the length distribution of the fiber spread portion is 60% or less, and the degree of entanglement N is defined by the following equation (1) using the length L of the fiber spread portion, The ratio N2 / N1 of the degree of entanglement N1 determined from the length L1 of the spread portion and the degree of entanglement N2 determined from the length L2 of the spread portion of the fiber after applying a load of 1.0 cN / dtex to the fiber is 0.8. A polyamide fiber as described above, wherein the fiber contains a pigment.
N = 1000 / L (1)
(2) The polyamide fiber according to (1), wherein the fiber has a tensile strength of 4.0 cN / dtex or more.
(3) The polyamide fiber according to (1) or (2), which contains 0.1% by weight or more of a pigment.
(4) The polyamide fiber as described in (1) to (3), further comprising carbon black as a pigment.
(5) A cloth comprising at least a part of the polyamide fiber according to (1) to (4).

According to the present invention, it is possible to provide a polyamide fiber that does not cause defects such as unevenness when fabric is produced and that can provide a fabric product having excellent physical properties.

FIG. 1 is a schematic view showing one example of a production process of a polyamide fiber according to the present invention.

Hereinafter, the polyamide fiber of the present invention will be described in detail.
The polyamide used for the polyamide fiber of the present invention is a high molecular weight product in which a so-called hydrocarbon group is connected to the main chain via an amide bond, and may be produced by a polycondensation reaction using aminocarboxylic acid or cyclic amide as a raw material. Alternatively, it may be produced by a polycondensation reaction using dicarboxylic acids and diamines as raw materials. Hereinafter, these raw materials are collectively referred to as monomers. Examples of the monomer include, but are not limited to, petroleum-derived monomers, biomass-derived monomers, and mixtures of petroleum-derived monomers and biomass-derived monomers. Such polyamides are not particularly limited, but examples include polycaprolactam, polyundecanolactam, polylauryl lactam or polyhexamethylene adipamide, polyhexamethylene sebacamide, polyhexamethylene dodecanediamide, and the like. Among them, polycaprolactam is preferred because it has excellent spinning properties and mechanical properties and is hard to gel.

  The polyamide in the present invention may be copolymerized or mixed with the second and third components in addition to the main component without departing from the object of the present invention. The copolymerization component can include, for example, a structural unit derived from an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid, an aromatic dicarboxylic acid, an aliphatic diamine, an alicyclic diamine, or an aromatic diamine. Is preferably 10 mol% or less, more preferably 5 mol% or less, as the monomer amount of the copolymer component based on the total monomer amount.

  The viscosity of the polyamide in the present invention may be selected within the range of common sense for producing clothing fibers, but it is preferable to use a polymer having a relative viscosity of 98% sulfuric acid of 2.0 or more and 4.0 or less. . If it is 2.0 or more, sufficient strength can be obtained when it is made into fibers, and if it is 4.0 or less, the extrusion pressure of the molten polymer during spinning and the rate of increase over time can be suppressed, and the production equipment This is preferable because an excessive load on the base and extension of the base replacement cycle can be achieved and productivity can be secured. In addition, when a fabric is produced using the fibers obtained in such a range, it is possible to obtain a fabric having a product strength of the fabric, for example, a tear strength, which is strong enough for practical use.

The polyamide fiber of the present invention is characterized by containing a pigment. Examples of the pigment used for the polyamide fiber of the present invention include inorganic pigments, organic pigments, natural pigments, and synthetic pigments, and are not particularly limited.
The polyamide fiber of the present invention preferably contains carbon black as a pigment. Carbon black is classified according to the production method, and examples thereof include acetylene black and thermal black produced by a pyrolysis method, and lamp black and furnace black produced by an incomplete combustion method. The type of carbon black contained in the polyamide fiber of the present invention is not particularly limited. However, furnace black is easy to control because of the effects on manufacturing costs, environmental impact, and particle size of carbon black. It is preferable that

The content of the pigment in the polyamide fiber of the present invention is preferably 0.1% by weight or more. By setting the content to 0.1% by weight or more, a polyamide fiber having a deep color unique to a pigment can be obtained. The upper limit of the content of the pigment is not particularly limited. However, since the yarn breakage during the production of the polyamide fiber can be suppressed, and the strength, which is the mechanical property of the polyamide fiber, can be increased, the upper limit is 5% by weight or less. Is more preferable. The content of the pigment may be identified by appropriately selecting a measurement method according to the pigment used. For example, when the polyamide fiber contains carbon black, the temperature range is from room temperature to 900 using TG-DTA. C., temperature rise rate: 100 ° C./min, air flow rate 20 ml / min, the weight change of the polyamide fiber was measured, and the value calculated from the ratio reduced in the region of 650 to 900 ° C. was regarded as the disappearance of carbon black. , The carbon black content in the polyamide fiber.
In addition, as long as the amount and type of the range do not impair the object of the present invention, additives for improving productivity such as heat resistance may be blended, and functions such as moisture absorption, antibacterial, ultraviolet shielding, and heat retention may be included. May be blended. The content of these additives is preferably in the range of 0.001 to 1% by weight based on the polyamide.
The polyamide fiber of the present invention needs to have a fineness variation of 1.0% or less. The fineness variation rate of the fiber was determined by measuring U% (Half) at a sample length of 500 m and measuring yarn speed of 100 m / min using USTER TESTER 5CX manufactured by Zellweger Uster, and obtaining the obtained U% (Half) value. did. The fineness variation rate of the fiber indicates unevenness of the fiber diameter of the entire fiber, and the smaller the fineness variation rate, the more uniform the fiber diameter. That is, by setting the fineness variation rate to 1.0% or less, unevenness and streaks do not occur in the woven fabric, and a product excellent in quality can be obtained. Preferably, the fineness variation rate is 0.6% or less.

  In the polyamide fiber of the present invention, the difference between the maximum fineness and the minimum fineness in the measurement of the fineness variation of the fiber is required to be 10% or less of the average fineness. The difference between the maximum fineness and the minimum fineness in the measurement of the fineness variation rate of the fiber is obtained by measuring U% (Normal) at a sample length of 500 m and a measuring yarn speed of 100 m / min using USTER TESTER 5CX manufactured by Zellweger Uster. Was the difference between the maximum and minimum values. The difference between the maximum fineness and the minimum fineness indicates unevenness generated in a part of the fiber. The smaller the difference between the maximum fineness and the minimum fineness, the more uniform the fiber diameter. When the difference between the maximum fineness and the minimum fineness is 10% or less, unevenness and streaks do not occur in the woven fabric, and a product having excellent quality can be obtained. Preferably, the difference between the maximum fineness and the minimum fineness is 5% or less of the average fineness.

  In the polyamide fiber of the present invention, the length L1 of the fiber opening portion needs to be 5 to 100 mm. By adopting such a range, the fibers are not separated for each single yarn during weaving, and the flight state of the yarn at the time of yarn driving when used as a weft becomes uniform, and unevenness and streaks do not occur in the woven fabric. , A product of excellent quality can be obtained. Preferably it is 5-70 mm.

  In the polyamide fiber of the present invention, the variation in the length L1 of the fiber opening portion needs to be 60% or less. Since the variation in the length of the fiber opening part is consistent with the variation in the manner in which the fibers are entangled, the convergence of the fibers is made uniform by setting the range, so that the individual yarns do not vary during weaving. In addition, when the yarn is used as a weft, the flight state of the yarn at the time of yarn driving becomes uniform, and unevenness and streaks do not occur in the woven fabric, so that a product with excellent quality can be obtained. Preferably it is 50% or less.

In the polyamide fiber of the present invention, when the degree of entanglement N is defined by the following formula (1) using the length L of the fiber spread portion, the degree of entanglement N1 obtained from the length L1 of the fiber spread portion and the fiber It is necessary that the ratio N2 / N1 of the degree of entanglement N2 obtained from the length L2 of the spread portion of the fiber after applying a load of 1.0 cN / dtex is 0.8 or more.
N = 1000 / L (1)
The load of 1.0 cN / dtex is equivalent to the tension applied to the fibers during weaving, and the ratio N2 / N1 of the degree of entanglement is a retention rate of entanglement of the fibers during weaving, that is, the ratio N2 / N1 of the degree of entanglement is 1. The closer the distance is, the more difficult it is to eliminate the entanglement of the fibers due to the tension applied to the fibers during weaving, and the more the entanglement imparted during the fiber production can be maintained. When tension is applied to the fibers due to warp warp or weft driving during weaving, the entanglement of the single yarns at the entangled portions of the fibers is released, and the length of the fiber spread portion becomes longer. As the length of the fiber opening increases, the fibers woven into the fabric tend to disperse from one fiber to another, causing single yarn breakage due to interference between adjacent fibers, and the rupture strength and tear strength of the woven fabric. Causes a decrease in Therefore, by increasing the entanglement retention during weaving, a woven fabric having excellent physical properties can be obtained. In other words, by setting the ratio N2 / N1 of the degree of entanglement N1 before applying a load of 1.0 cN / dtex to the fiber and the degree of entanglement N2 after applying the load to the fiber, the physical properties such as tear strength are excellent. A fabric can be obtained. More preferably, it is 0.9 or more.

  The polyamide fiber of the present invention preferably has a tensile strength in a fiber tensile test of 4.0 cN / dtex or more. By setting the content in such a range, a fabric excellent in physical properties such as tear strength can be obtained. More preferably, it is 4.5 cN / dtex or more.

  The elongation of the polyamide fiber of the present invention may be appropriately set according to the application, but is preferably 35 to 60% from the viewpoint of workability when processing into a fabric.

  Next, a load of 1.0 cN / dtex is applied to the above-described fineness variation rate, the difference between the maximum fineness and the minimum fineness when measuring the fineness variation rate, the length of the spread portion, the variation in the length distribution of the spread portion, and the fiber. A preferred embodiment for satisfying the retention rate of the confounding degree at the time will be described.

  An example of the method for producing a polyamide fiber of the present invention will be specifically described with reference to FIG. FIG. 1 is a schematic view showing one example of a production process of a synthetic fiber according to the present invention.

  A steam ejection device 2 in which the melted polyamide chips are measured and transported by a gear pump, discharged from the spinneret 1, and steam is jetted toward a spinneret surface provided immediately below the spinneret; The yarn is cooled and solidified to room temperature by passing through a region provided with the cooling air from the cooling device 3 and provided downstream of the cooling device 2, and then the oil is supplied by the oil supply device 4 to bundle the yarn, and Pre-entanglement is applied by the fluid entanglement nozzle device 5, and is passed through the take-up roller 6 and the stretching roller 7. At this time, the yarn is drawn according to the ratio of the peripheral speeds of the take-up roller 6 and the drawing roller 7. Further, the yarn is heat-set by heating the drawing roller 7, the main entanglement is given by a second fluid entanglement nozzle device 8 provided below the drawing roller, and the yarn is wound by a winder (winding device) 9. In order to obtain the polyamide fiber of the present invention, as shown in FIG. 1, the pre-entanglement by the first fluid entanglement nozzle device before the take-up roller and the main entanglement by the second fluid entanglement nozzle device after the drawing roller. , Making the pressure of the fluid at the time of applying the pre-entanglement and the main entanglement an appropriate range, preferably controlling the spinning draft, and setting the oil supply device 4 for adhering the oil agent to the fiber at an appropriate position. That is, the single fiber fineness of the fiber is set in an appropriate range. These will be described in detail.

  As shown in FIG. 1, the method for producing a polyamide fiber according to the present invention includes the pre-entanglement by the first fluid entanglement nozzle device before the take-up roller and the main entanglement by the second fluid entanglement nozzle device after the drawing roller. It is important to give

  The polyamide fiber of the present invention contains a pigment in the fiber, and since this pigment is exposed on the fiber surface, the coefficient of friction between the fiber surface and various rollers is lower than that of the fiber containing no pigment. When the coefficient of friction between the various rollers is reduced, the force of the rollers for gripping the fibers is reduced. When the fiber gripping force of the roller decreases in this way, the tension of the fiber increases during drawing between the take-up roller and the drawing roller, so that the fiber slips particularly at the take-up roller. Here, if fiber slip occurs in the take-up roller, the running speed of the fiber in the portion where the slip occurs becomes faster than the circumferential speed of the take-up roller, and therefore, the draw ratio calculated from the ratio of the circumferential speed of the take-up roller and the draw roller. Since the actual stretching ratio is further reduced, stretching becomes poor. When the slip occurs and the stretching is poor, the fiber diameter of the stretch-defective portion becomes large. For this reason, a difference in fiber diameter occurs between the normal portion and the poorly stretched portion, and the fineness variation rate increases.If the fiber including the poorly stretched portion is used in the woven fabric, the poorly stretched portion becomes uneven or streaked, and the quality of the woven fabric decreases. Let it.

  Further, in the above-described method for producing a polyamide fiber, poor stretching due to slipping by the take-off roller tends to occur particularly at the entangled portion of the fiber. In the entangled portion of the fibers, the single yarns are entangled with each other, and the surface area of the fiber is smaller than that in the opened portion. Therefore, the entangled portion of the fiber has a lower coefficient of friction with the take-off roller and the stretching roller than the opened portion. When the friction coefficient is reduced in the entangled portion of the fiber, the entangled portion of the fiber locally slips due to the tension applied to the fiber between the take-up roller and the drawing roller, and a local poor stretch portion occurs in the fiber. That is, the fiber diameter locally increases, the fiber variation rate deteriorates, and the difference between the maximum fineness and the minimum fineness in the measurement of the fiber fineness variation rate increases. Thereby, when it is made into a woven fabric, it becomes uneven or streaked, and the quality of the woven fabric is reduced. Furthermore, since the polyamide fiber of the present invention contains a pigment and has a lower coefficient of friction than a fiber containing no pigment, it has been found that local fiber slip is likely to occur at the entangled portion.

  In order to reduce the slip at the entangled portion of the fiber, it is necessary to reduce the entanglement given to the fiber before drawing by the first fluid entanglement nozzle device. As a method of reducing the degree of entanglement before stretching, a method of reducing the ejection pressure of the fluid in the first fluid entanglement nozzle device is useful. On the other hand, when the ejection pressure of the fluid in the first fluid entanglement nozzle device is reduced, the length L1 of the fiber spread portion increases, and the variation in the length L1 of the fiber spread portion increases. When the obtained fiber is used as a fabric, the fabric becomes uneven or streaked, and the quality of the fabric is deteriorated.

  For the above reasons, as shown in FIG. 1, the method for producing a polyamide fiber of the present invention employs the pre-entanglement by the first fluid entanglement nozzle device before the take-up roller and the second fluid entanglement nozzle device after the drawing roller. It is important to give confounding in this confounding. In the first fluid entanglement nozzle device, entanglement is provided so that the fibers do not slip on the take-off roller, so that variation in the target fiber opening length L1 and the fiber opening portion length L1 can be obtained. Is entangled with a second fluid entanglement nozzle device after the stretching roller.

  It is preferable that the ejection pressure of the fluid when applying the pre-entanglement by the first fluid entanglement nozzle device is 0.05 MPa or more and 0.20 MPa or less. As described above, by setting the ejection pressure in such a range, it is possible to suppress the slip of the fiber at the take-off roller, and to prevent the occurrence of poor drawing, the fineness variation rate, the maximum fineness at the time of the fineness variation rate measurement and The difference in the minimum fineness is appropriate, and when stretching between the take-up roller and the stretching roller, the yarn does not break apart for each single yarn and breakage does not occur. Excellent product can be obtained. More preferably, it is 0.05 MPa or more and 0.15 MPa or less.

  Further, it is preferable that the ejection pressure of the fluid at the time of applying the main entanglement by the second fluid entanglement nozzle device is 0.15 MPa or more and 0.30 MPa or less. By setting the ejection pressure in such a range, the degree of entanglement of the fibers can be increased. On the other hand, since the fiber strength does not decrease due to contact with the entanglement nozzle device, unevenness and streaks do not occur in the woven fabric, and the quality is high. Excellent product can be obtained. More preferably, it is 0.15 MPa or more and 0.20 MPa or less.

  In the production of the polyamide fiber of the present invention, the spinning draft represented by the ratio of the linear speed of the die discharge to the speed of the take-up roller 6 is preferably 70 or more and less than 200. Here, the die discharge linear velocity is a value obtained by dividing the discharge volume per unit time of the polymer discharged from the discharge hole of the spinning die 1 by the cross-sectional area of the die discharge hole. The spinning draft has a correlation with the tension applied to the fiber from the time when the spinning draft is discharged from the discharge hole of the spinneret 1 to the time when the spinning draft is cooled by the pulling roller 6, and the larger the spinning draft, the higher the draft is drawn by the pulling roller 6. Up to the fiber. As the tension applied to the fiber before being taken up by the take-up roller 6 is larger, the pre-entanglement is less likely to be given to the fiber by the first fluid entanglement nozzle device 5, while the tension applied to the fiber until the take-up roller 6 takes up the fiber The smaller the smaller, the easier the pre-entanglement is imparted to the fiber by the first fluid entanglement nozzle device 5. That is, by controlling the spinning draft in such a range, the preliminary entanglement imparted by the first fluid entanglement nozzle device 5 becomes appropriate, the fiber does not slip on the take-off roller 6, and the fineness variation rate, the fineness variation rate The difference between the maximum fineness and the minimum fineness at the time of measurement is appropriate, and the fibers are not separated into single yarns at the time of drawing, and there is no breakage in drawing. Product can be obtained. More preferably, it is 100 or more and less than 180.

  In the production of the polyamide fiber of the present invention, it is preferable that the diameter is 600 mm or more and 2000 mm or less from the spinneret surface of the oil supply device 4 for applying an oil agent to the fiber. By setting the position of the lubricating device 4 to the range, the pre-entanglement provided by the first fluid entanglement nozzle device 5 becomes appropriate, the fiber does not slip on the take-off roller 6, the fineness variation rate, the fineness variation rate The difference between the maximum fineness and the minimum fineness at the time of measurement is appropriate, and the fibers are not separated into single yarns at the time of drawing, and there is no breakage in drawing. Product can be obtained. More preferably, it is 1000 mm or more and 1500 mm or less.

The single fiber fineness of the polyamide fiber of the present invention is preferably 0.8 dtex or more and 2.0 dtex or less. Since the thickness of the single-fiber fineness has a correlation with the ease with which entangling is provided, by selecting a single-fiber fineness in such a range, the degree of pre-entanglement by the first fluid entanglement nozzle device 5 becomes appropriate, and the take-up roller 6 The fibers do not slip at the same time, and the fineness variation rate, the difference between the maximum fineness and the minimum fineness when measuring the fineness variation rate are appropriate, and the fibers are separated into single yarns at the time of drawing, and the drawing breakage occurs. Nor. Furthermore, since the degree of imparting the main entanglement by the second fluid entanglement nozzle device 8 is also appropriate, the length of the fiber spread portion, the dispersion of the length distribution of the fiber spread portion, and the retention rate of the entanglement become appropriate. Therefore, it is possible to obtain a product having excellent quality without unevenness or streaks in the woven fabric. More preferably, it is 0.8 dtex or more and 1.5 dtex or less.
In addition, the cross-sectional shape of the polyamide fiber of the present invention can adopt not only a round cross-section but also a variety of cross-sectional shapes such as a flat shape, a Y-type, a T-type, a hollow type, a field type, and a well type.

The present invention will be described in detail with reference to examples. In addition, the following method was used for the measuring method in an Example.
[Measuring method]
A. Relative viscosity of sulfuric acid 0.25 g of a sample was dissolved in 100 ml of sulfuric acid having a concentration of 98 wt%, adjusted to a concentration of 1 g / l, and the falling time (T1) at 25 ° C. was measured using an Ostwald viscometer. Subsequently, the falling time (T2) of only 98 wt% sulfuric acid was measured. The ratio of T1 to T2, that is, T1 / T2, was defined as sulfuric acid relative viscosity.

B. Melting point (Tm)
Using a differential scanning calorimeter DSC-7 manufactured by Perkin Elmer, 20 mg of the sample polymer was used as the first RUN, and the temperature was raised from 20 ° C. to 270 ° C. at a temperature rising rate of 20 ° C./min and at a temperature of 270 ° C. for 5 minutes. After holding, the temperature was lowered from 270 ° C. to 20 ° C. at a temperature lowering rate of 20 ° C./min, held at a temperature of 20 ° C. for 1 minute, and further raised as 2nd RUN from 20 ° C. to 270 ° C. at a rate of 20 ° C./min. The temperature of the endothermic peak observed when heated was taken as the melting point.

C. A fineness sample was prepared into a 200-roll wrap with a measuring machine with a frame circumference of 1.125 m, dried with a hot air drier (105 ± 2 ° C x 60 minutes), weighed with a balance, and the official moisture content was determined. The fineness was calculated from the multiplied value. The measurement was performed four times, and the average value was defined as fineness. A value obtained by dividing the obtained fineness by the number of filaments was defined as a single fiber fineness.

D. Tensile Strength and Elongation Measured using "TENSILON" (registered trademark) UCT-100 manufactured by Orientec Co., Ltd. as a measuring device under constant-speed elongation conditions shown in JIS L1013 (Test method for chemical fiber filament yarn, 2010). . The elongation was determined from the elongation at the point showing the maximum strength in the tensile strength-elongation curve. The tensile strength was defined as the value obtained by dividing the maximum strength by the fineness. The measurement was performed 10 times, and the average value was defined as the tensile strength and elongation.

E. FIG. Carbon black content (% by mass)
Using TG-DTA (thermogravimeter SII TG / DTA 6200, manufactured by Nanotechnology) and 1.4 mg of a sample of black polyamide yarn, temperature range: room temperature to 900 ° C., heating rate: 100 ° C./min, atmosphere It is a value calculated by measuring a weight change of the polyamide fiber under the condition of a flow rate of 20 ml / min and reducing the weight in a region of 650 to 900 ° C.

F. Fineness variation rate U% (Half) was measured using a USTER TESTER 5CX manufactured by Zellweger Uster at a sample length of 500 m and a measuring yarn speed of 100 m / min, and the obtained value of U% (Half) was defined as the fineness variation rate. did.

G. FIG. Difference between the maximum fineness and the minimum fineness The difference between the maximum value and the minimum value in the U% (Normal) chart in the measurement of the fineness variation rate in the above section F was defined as the difference between the maximum fineness and the minimum fineness.

H. Entanglement measurement method Using ENTANGLEMENT TESTERR-2040 manufactured by Rothschild (Switzerland), measurement speed: 2.5 m / min, trip tension level: 1.2 cN, yarn length: 0.5 m until next needle insertion after trip, and number of repetition measurements: 50 times And the sample was continuously measured. The yarn length from the needle piercing part to the measurement yarn to the trip tension level (1.2 cN) and tripping is considered as the spread length of the non-entangled part, and from the obtained 50 data, Determined by
(A) Length L of the spread portion
It was determined from the average of the obtained 50 data.
(B) Variation in the length of the spread part (CV)
Using the length L of the spread portion and the standard deviation S of the obtained 50 data, it was obtained from the following equation.
CV (%) = S / L × 100
(C) Degree of confounding N
Using the length L of the spread portion, it was obtained from the following equation.
N = 1000 / L.

I. After applying a load of 1.0 cN / dtex, the fiber is run at a speed of 100 m / min with a load of 1.0 cN / dtex applied between rollers having a mirror surface having two pairs of entanglement levels after a 1.0 cN / dtex weighting process, and then wound up. Perform processing. The entanglement degree of the above item H (c) is measured with the fiber after the weighting treatment.

J. Fabric Visual Inspection A polyamide fabric of the present invention was used for the weft to produce a woven fabric.Evaluation was made in the following three stages according to the state of unevenness and streaks per 50 m of the woven fabric by visual inspection. did.
A: The fabric has no streaks or unevenness and has excellent quality.

  ：: Slight streaks and unevenness occurred, but no problem for use as a product.

  ×: Streaks or unevenness occurred, and the product could not be used.

K. Tear strength of woven fabric The tear strength of woven fabric is determined according to the tear strength JIS method D method (wet grab method) specified in 8.18.1 of JIS L 1096 (Testing method of woven fabric and knitted fabric, 2010). Based on the measurement in the weft direction, when the tear strength was 6.0 N or more, it was judged that the fabric strength that could withstand practical use was obtained.

(Example 1)
(Manufacture of polyamide fiber)
As a base polymer, polycaprolactam having a titanium oxide content of 0.02% by weight (sulfuric acid relative viscosity: 2.60, melting point: 220 ° C.) was dried by a conventional method so as to have a water content of 0.03% by weight or less. The polycaprolactam was kneaded with a furnace method carbon black having a DBP lubrication amount of 180 ml / 100 g by a twin-screw kneader so that the content was 15% by weight with respect to the base polymer, and was discharged after passing through a 30 μm cut filter. Chips were manufactured and dried by a conventional method so as to have a water content of 0.03% by weight or less. The obtained polycaprolactam master chip containing carbon black and the polycaprolactam chip of the base polymer were blended at a ratio of 1:15 to obtain a polycaprolactam base chip containing 1.0% by weight of carbon black. The base chip was put into the spinning machine shown in FIG. 1, melted at a spinning temperature of 265 ° C., and spun from a spinneret 1 having 80 round holes with a discharge hole diameter of 0.16 mm and a hole length of 0.32 mm. The yarn is cooled and solidified by blowing cool air onto the yarn by the cooling device 3 and refueled by the oil supply device 4 installed at a position 1000 mm from the surface of the spinneret. Then, the first fluid entanglement nozzle device 5 reserves at a fluid ejection pressure of 0.05 MPa. Entangling was performed, and the peripheral speed (take-off speed) of the take-off roller 6 was taken out at 2180 m / min (set value). Subsequently, the yarn drawn by the take-off roller 6 is drawn by a draw roller 7 having a surface temperature of 155 ° C., so that the yarn is drawn at a draw ratio of 1.75 times between the rollers. The main entanglement was applied at a fluid ejection pressure of 0.15 MPa, and the film was wound by a winder 9 having a winding speed of 3700 m / min (set value) to obtain a polycaprolactam multifilament of 22 dtex-20 filaments.

(Manufacture of textiles)
A 22dtex-20 filament-free polycaproamide fiber is used for the warp, and the polyamide multifilament is used for the weft. The warp density is set to 188 / 2.54 cm and the weft density is set to 155 / 2.54 cm. Weaved.

  The obtained greige fabric was scoured with a solution containing 2 g of caustic soda (NaOH) per liter by an open soaper according to a conventional method, dried at 120 ° C. in a cylinder drier, and then preset at 170 ° C. Thereafter, the temperature was increased to 120 ° C. at a rate of 2.0 ° C./min by a pressure-resistant drum type dyeing machine, and dyeing was performed at a set temperature of 120 ° C. for 60 minutes. After dyeing, the fabric was washed with running water for 20 minutes, dehydrated, and dried to obtain a woven fabric having a density of 200 pieces / 2.54 cm and a weft density of 160 pieces / 2.54 cm. The number of occurrences of yokomura during the production of the fabric and the tear strength of the obtained fabric were evaluated by the above method. Table 1 shows the results.

(Example 2)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the fluid ejection pressure of the first fluid entanglement nozzle device 5 was set to 0.18 MPa. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 3)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the fluid ejection pressure of the second fluid entanglement nozzle device 8 was set to 0.22 MPa. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 4)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the position of the oiling device 4 was set at 800 mm from the spinneret surface. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 5)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the position of the oiling device 4 was 1800 mm from the spinneret surface. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 6)
A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that spinning was performed from a spinneret 1 having 80 holes with a discharge hole diameter of 0.14 mm and a hole length of 0.28 mm. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 7)
A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that spinning was performed from a spinneret 1 having 80 round holes with a discharge hole diameter of 0.20 mm and a hole length of 0.40 mm. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 8)
A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that spinning was performed from a spinneret 1 having 48 round holes with a discharge hole diameter of 0.20 mm and a hole length of 0.40 mm. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Example 9)
A polycaprolactam master chip containing carbon black and a base polymer polycaprolactam chip obtained by the method described in Example 1 were blended at a ratio of 1:30, and a polycaprolactam base chip containing 0.5% by weight of carbon black. A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the obtained chip was used. Table 1 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 1)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the fluid ejection pressure of the first fluid entanglement nozzle device 5 was set to 0.25 MPa. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 2)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the second fluid entangled nozzle device 8 was not used. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 3)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the fluid ejection pressure of the first fluid entangled nozzle device 5 was set to 0.25 MPa and the second fluid entangled nozzle device 8 was not used. Was. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 4)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the first fluid entangled nozzle device 5 was not used. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 5)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the position of the oiling device 4 was set at 500 mm from the spinneret surface. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 6)
A polycaprolactam multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that the position of the oiling device 4 was set at 3000 mm from the spinneret surface. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 7)
A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that spinning was performed from a spinneret 1 having 80 round holes with a discharge hole diameter of 0.10 mm and a hole length of 0.20 mm. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 8)
A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that spinning was performed from a spinneret 1 having 80 round holes with a discharge hole diameter of 0.25 mm and a hole length of 0.50 mm. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

(Comparative Example 9)
A multifilament and a woven fabric were obtained under the same conditions as in Example 1 except that spinning was performed from a spinneret 1 having 32 round holes with a discharge hole diameter of 0.25 mm and a hole length of 0.50 mm. Table 2 shows the evaluation results of the obtained multifilament and woven fabric.

It is possible to provide a polyamide fiber which does not cause defects such as unevenness when a fabric is produced and which can provide a fabric product having excellent physical properties.

1: spinneret 2: steam ejection device 3: cooling device 4: oil supply device 5: first fluid entanglement nozzle device 6: take-up roller 7: stretching roller 8: second fluid entanglement nozzle device 9: winder (winding device)

Claims (5)

The fineness variation rate is 1.0% or less, the difference between the maximum fineness and the minimum fineness in the fineness variation rate measurement is 10% or less of the average fineness, and the length L1 of the fiber opening portion is 5 to 100 mm; When the dispersion of the length distribution of the fiber spread portion is 60% or less and the degree of entanglement N is defined by the following equation (1) using the length L of the fiber spread portion, the fiber spread portion The ratio N2 / N1 of the degree of entanglement N1 determined from the length L1 of the fiber and the degree of entanglement N2 determined from the length L2 of the fiber spread portion after applying a load of 1.0 cN / dtex to the fiber is 0.8 or more. A polyamide fiber, characterized in that the fiber contains a pigment.
N = 1000 / L (1) The polyamide fiber according to claim 1, wherein the fiber has a tensile strength of 4.0 cN / dtex or more. The polyamide fiber according to claim 1, comprising a pigment in an amount of 0.1% by weight or more.   The polyamide fiber according to any one of claims 1 to 3, wherein the pigment contains carbon black. A fabric comprising at least a part of the polyamide fiber according to claim 1.

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