KR20210004950A - Polyamide fiber and woven fabric, and method for producing polyamide fiber - Google Patents

Abstract

An object of the present invention is to provide a polyamide fiber having good color development and excellent dyeing fastness. To achieve this purpose, polyamide fibers are polyamide fibers containing an aliphatic polyamide as a main component, and the amount of amino terminal groups in the aliphatic polyamide is 7×10 ^-5 mol/g or more and 10.0×10 ^-5 mol/ It is a polyamide fiber in which g or less and the rigid amorphous amount required for the polyamide fiber is 40% or more.

Description

Polyamide fiber and woven fabric, and method for producing polyamide fiber

The present invention relates to a polyamide fiber excellent in color development and dyeing fastness.

Polyamide fibers, such as those represented by polycapramid and polyhexamethyleneadipamide, are widely used in medical applications, industrial materials, etc. because they have excellent mechanical properties, chemical resistance, and heat resistance. In particular, it is used in many medical applications due to its excellent strength and abrasion resistance. In addition, in recent years, the diversification of fashion and the expansion of use are in progress, and performance improvement is required for inner wear, sports wear, casual wear, and the like. In particular, in recent years, the demand for polyamide fibers excellent in color development properties, particularly matt tone color development properties, is increasing.

Until now, various proposals have been made as a technique for improving the dyeability of polyamide fibers. For example, Patent Document 1 proposes a multicolored bulky yarn composed of synthetic fibers with different dyeing properties, and as an example, a polymer with a large amount of NH ₃ end groups that are well stained with acid dyes and the amount of NH ₃ end groups slightly stained with an acid dye. Fewer polymer combinations have been described. In addition, in Patent Document 2, a polyamide fiber having 3 to 6.5% titanium oxide and an amount of terminal amino groups of 4×10 ^{-5 to} 8×10 ^-5 mol/g is proposed.

Since the polyamide fiber has an amide bond or an amino terminal group capable of forming an ionic bond with a dye molecule in the fiber structure, it is dyed with good color development by an ion-binding dye (such as an acid dye). Therefore, as described in Patent Literatures 1 and 2, the more the amino terminal group is, the more dyeing seats of the dye are, and thus, a technique for improving dyeing properties and color development properties is being developed.

Japanese Patent Laid-Open No. Hei 7-189067 Japanese Patent Publication No. 2004-292982

However, although the polyamide exemplified in Patent Document 1 is described as a polymer having a large amount of NH ₃ end groups that are well stained with acid dyes, there is no specific disclosure of the amount of NH ₃ end groups, but it can be inferred that the color development properties will be improved. In addition, polyamide fibers before multicolor bulky processing for carpet applications have a problem that dyeing fastness is inferior from the viewpoint of fiber structure for partial oriented yarns. In addition, the oriented yarn is one with few amorphous parts, but the partial oriented yarn is a yarn in which the oriented part is partial.

Dyeing fastness is the degree of robustness of dyeing against various external conditions such as sunlight, washing, sweat, friction, acid, and iron. Practically, it is expressed by light fastness and washing fastness. In addition, the polyamide fiber described in Patent Document 2 improves color development by defining the amount of amino terminal groups for medical use, but as the amount of titanium oxide, which is a white pigment, is increased, the color development property decreases, the fiber orientation tends to become loose, and the fiber structure From the viewpoint of, there was a problem that the dyeing fastness was inferior.

Thus, while the polyamide fiber disclosed in Patent Documents 1 and 2 obtains a polyamide fiber having excellent color development properties, there has been a problem in that dyeing fastness is inferior in the polyamide fiber for medical use with strict dye fastness standards.

Therefore, it is an object of the present invention to provide a polyamide fiber excellent in color development and fastness.

The above problem can be solved by the following configuration.

(1) A polyamide fiber containing an aliphatic polyamide as a main component, wherein the amount of amino terminal groups in the aliphatic polyamide is 7.0×10 ^-5 mol/g or more and 10.0×10 ^-5 mol/g or less, and a polyamide fiber A polyamide fiber having 40% or more of the rigid amorphous amount required for.

(2) The polyamide fiber according to (1), containing 0.1 to 10.0% by weight of titanium oxide based on the total amount of the fiber.

(3) The polyamide fiber according to (1) or (2), having a total fineness of 5 to 235 dtex.

(4) Medical woven fabric comprising the polyamide fiber according to any one of (1) to (3).

(5) A polyamide resin raw material is melted, the polyamide resin is discharged from a detent, cooled and solidified to form a yarn, and the yarn is stretched and heat treated, and then wound up to produce a polyamide fiber. A polyvalent aliphatic polyamide is included, and the amount of the amino terminal group in the aliphatic polyamide is 7.0×10 ^-5 mol/g or more and 10.0×10 ^-5 mol/g or less, and the following steps (a) to (d) A method for producing a polyamide fiber comprising a.

(a) The discharge process in which the take-up speed is 1300m/min to 2400m/min.

(b) A stretching step in which the thread is stretched by the draft ratio of the take-up roller and the stretching roller, and the temperature of the stretching roller is 150 to 190°C and the draw ratio is 1.7 to 3.0 times.

(c) After the stretching treatment, the thread is relaxed between the stretching roller and the take-up roller, and the relaxation treatment step is 0 to 2.0%.

(d) A winding process in which the winding speed is 3000 to 4500 m/min.

(Effects of the Invention)

According to the present invention, it is possible to provide a polyamide fiber excellent in color development and dyeing fastness.

Hereinafter, the polyamide fiber of the present invention will be described in detail.

The polyamide used in the polyamide fiber of the present invention is a high molecular weight substance in which a so-called hydrocarbon group is connected to the main chain through an amide bond, and may be prepared by polycondensation reaction using aminocarboxylic acid or cyclic amide as raw materials, or dicarboxyl Acid and diamine may be used as raw materials by a polycondensation reaction. Hereinafter, the raw materials for these high molecular weight substances are referred to as monomers. The monomer is not limited, such as a petroleum-derived monomer, a biomass-derived monomer, a mixture of a petroleum-derived monomer and a biomass-derived monomer. Such polyamides are not particularly limited, but examples include polycaproamide, polyundecanolactam, polylauryllactam or polyhexamethylene adipamide, polyhexamethylene sebacamide, polyhexamethylenedodecanediamide, and the like. Among these, polycaproamide is preferable because it has excellent yarn spinning properties and mechanical properties, and is difficult to gelatinize.

In the polyamide fiber of the present invention, in addition to the monomer components most included (for example, cyclic amide or dicarboxylic acid and diamine), the second and third components are copolymerized or You may mix it. As a copolymerization component, structural units derived from aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, aromatic dicarboxylic acid, aliphatic diamine, alicyclic diamine, and aromatic diamine can be contained, for example.

In the present invention, the "polyamide fiber containing an aliphatic polyamide as a main component" is a polyamide copolymer fiber containing an aliphatic polyamide component as a main component. Here, the meaning of the main component means that the proportion of the aliphatic polyamide to the total polyamide component is 90% by weight or more. In addition, when both the main monomer and the monomer to be copolymerized form an aliphatic polyamide, the total amount may be 90% by weight or more.

The viscosity of the polyamide in the present invention may be selected from a common sense range for producing medical 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. By setting it as such a range, practical yarn strength is obtained. In addition, since the tension at the time of optimal stretching and heat setting is applied, crystallization or orientation of the polyamide proceeds, the amount of rigid amorphous is increased, and thus an appropriate value is obtained, and the color fastness is improved. On the other hand, if the relative viscosity of sulfuric acid is 4.0 or less, it is possible to produce a melt viscosity suitable for spinning, and is preferable.

In addition, the polyamide fiber of the present invention includes various additives, such as chlorine, flame retardant, antioxidant, ultraviolet absorber, infrared absorber, nucleating agent, fluorescent whitening agent, antistatic agent, moisture absorbent (polyvinylpyrrolidone, etc.), antibacterial agent. (Silver zeolite, zinc oxide, etc.) may be added as necessary in an amount between 0.001 to 10% by weight of the total polyamide fiber.

The amount of amino terminal groups of the polyamide fibers of the present invention is 7.0×10 ^-5 mol/g or more. Since the amino terminal group becomes a dye conjugation, when the amount of the amino terminal group is 7.0 × 10 ^-5 mol/g or more, color development suitable for medical use is obtained. If it is less than 7.0 × 10 ^-5 mol/g, since the amino terminal group on which the dye is seated is insufficient, color development is inferior and development to medical use is difficult. Further, the larger the amount of the amino terminal group is, the more preferable it is, but the upper limit value in the present invention is about 10×10 ^-5 mol/g. It is preferably 7.5×10 ^-5 mol/g or more, more preferably 8.0×10 ^-5 mol/g or more.

Rigid amorphous is an amorphous whose amount is required by the method described in the section of the embodiment, in the intermediate state between crystal and mobile amorphous (conventional complete amorphous), even above the glass transition temperature (Tg). Molecular motion is frozen, and it is amorphous that becomes fluid at a temperature higher than Tg (for example, Minoru Tokito, 「DSC(3)-Glass Transition Behavior of Polymer」, Journal of the Textile Sciences (Fiber and Industry), Vol. 65, No. 10 (2009)). The rigid amorphous amount (rate) is meant as 100%-crystallinity-moving amorphous amount.

In the present invention, the polyamide fiber includes a crystalline portion, a rigid amorphous portion, and a movable amorphous portion.

And the amount of rigid amorphousness required in the polyamide fiber is 40% or more. When the rigid amorphous amount is 40% or more, the dye blended in the movable amorphous part is suppressed, and since the dye is selectively seated at the amino terminal group, excellent color development and excellent color fastness are expressed. When the rigid amorphous amount is less than 40%, since many dyes are mixed in the movable amorphous part, the dye is removed from the movable amorphous part in the fastness evaluation, and excellent dyeing fastness cannot be obtained. Further, the larger the rigid amorphous amount is, the more preferable it is, but it is preferably 42% or more, and more preferably 45% or more. The upper limit in the present invention is about 50% from the viewpoint of productivity. Compared with the movable amorphous portion that the dye is easily removed from the rigid amorphous portion, the dye retains and excellent dyeing fastness is obtained.

It is preferable that the polyamide fiber of the present invention contains 0.1 to 10.0% by weight of titanium oxide based on the total amount of the fiber. Titanium oxide is known as an excellent white pigment, and is widely used in synthetic fibers as a chlorine agent. Because of its white pigment, when it is contained in the fiber, the appearance of the medical product becomes pale and it is difficult to obtain a dark color. When the content of titanium oxide is increased, a color with high whiteness (pastel tone) tends to be obtained, and the dyeability decreases. In particular, the polyamide fiber of the present invention has an amino terminal group amount of 7 × 10 ^-5 mol/g or more, so that even if titanium oxide is contained, there are many dyes that can be seated at the amino terminal group. The effect appears more remarkably and is preferable. The amount of titanium oxide based on the total amount of fibers is preferably 0.3 to 5.0% by weight, more preferably 1.5 to 3.0% by weight. As the titanium oxide, an inert one generally used as a white pigment is preferred, and titanium oxide having an average particle diameter of 1 mu m or less is preferably used in order to prevent deterioration of the physical properties of the fiber.

It is preferable that the polyamide fiber of the present invention has a tensile strength of 2.5 cN/dtex or more. More preferably, it is 3.0 cN/dtex or more. By setting it as such a range, it becomes possible to provide medical treatment excellent in strength that can withstand actual use in medical applications mainly for inner medical use or sports medical use.

It is preferable that the polyamide fiber of the present invention has an elongation of 35% or more. The preferred range is 35 to 50%. By setting it as such a range, it has color development property and color fastness, and a fiber suitable for medical use can be obtained, and it is preferable. Further, the process passability in higher-order processes such as weaving, knitting, and twisting becomes good.

Considering that the polyamide fiber of the present invention is used as a medical long fiber material, the total fineness as a multifilament is 5 to 235 decitex, and the number of filaments is preferably 1 to 144 filaments. If the single yarn fineness is made thin, softness can be obtained, but the appearance of the medical article becomes whitish due to diffuse reflection of light, making it difficult to obtain a dark color, and the dye is easily removed from the amorphous portion. It is preferable that the total fineness is 5 to 235 decitex from the viewpoint of the touch, color development, and color fastness required as a medical product. In particular, the polyamide fiber of the present invention has an amino terminal group amount of 7×10 ^-5 mol/g or more and a stiff amorphous amount of 40% or more, so that even if the single yarn fineness is reduced, the dye is selectively seated at the amino terminal group. By suppressing the dye blended in the movable amorphous part, the effect of color development and color fastness is more pronounced. More preferably, the total fineness is 5 to 110 decitex.

The cross-sectional shape of the polyamide fiber of the present invention is preferably circular, triangular, flat, lenticular (flat convex), beans-shaped (flat concave), Y-shaped, cross-shaped, and star-shaped.

Next, a method for producing the aliphatic polyamide fiber of the present invention will be described.

The method for producing the polyamide polymer used for the polyamide fiber of the present invention is not particularly limited. A polyamide having a desired amino group amount and titanium oxide content can be produced by adding a diamine as an amino terminal group amount modifier and a chlorinated titanium oxide to the polyamide monomer and performing known polycondensation. Diamine and titanium oxide may be added in the raw material stage or added during the polycondensation reaction. Further, by blending two or more of the produced polyamide polymers, the desired amount of amino groups and titanium oxide content can be obtained. The blending method is not particularly limited, and melt mixing using an extruder or the like, dry blending of mixing pellets, and the like may be mentioned.

As the diamine of the amino terminal group regulator, for example, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8- Diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1, 14-diaminotetradecane, 1,15-diaminopentadecane, 1,16-diaminohexatecan, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminonona Aliphatic diamines such as decane, 1,20-diaminoechoic acid, 2-methyl-1,5-diaminopentane, cyclohexanediamine, alicyclic diamines such as bis-(4-aminohexyl)methane, and xylenediamine Aromatic diamines and the like.

The relative viscosity of the polyamide polymer used for the polyamide fiber of the present invention is the relative viscosity at 25° C. of a 98% sulfuric acid solution having a sample concentration of 0.01 g/mL, preferably 2.0 or more. It is more preferably 2.05 to 7.0, particularly preferably 2.1 to 6.5, and most preferably 2.15 to 6.0. If the relative viscosity is 2.0 or more, the yarn strength of the polyamide fiber can be expressed, and if it is 8.0 or less, the melt spinning property is not difficult, and thus it is preferable.

The polyamide polymer used in the polyamide fiber of the present invention can further contain a known end sealant because of molecular weight control. Monocarboxylic acid is preferable as the end capping agent. In addition, acid anhydrides such as phthalic anhydride, monoisocyanates, monocarboxylic acid halides, monoesters, and monoalcohols may be mentioned. The monocarboxylic acid that can be used as the end sealant is not particularly limited as long as it has reactivity with an amino group, but for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid , Myristic acid, palmitic acid, stearic acid, pivalic acid, aliphatic monocarboxylic acids such as isobutylic acid, alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid, benzoic acid, toluic acid, α-naphthalene carboxyl And aromatic monocarboxylic acids such as acids, β-naphthalene carboxylic acid, methylnaphthalene carboxylic acid, and phenylacetic acid. In the present invention, one or more of these monocarboxylic acids may be used.

The polyamide fiber of the present invention can be produced by a known melt spinning device. As an example of known melt spinning, pellets of polyamide resin, etc., are melted, metered and transported by a gear pump, discharged from the spinneret, and cooled to room temperature by blowing cooling air with a thread cooling device such as a chimney. It is a trend. The thread is lubricated by the oil supply device and converges, entangled by the fluid interlocking nozzle device, and passes through the take-up roller and the stretching roller. At that time, it is stretched in accordance with the ratio of the circumferential speed of the take-up roller and the stretching roller. Further, heat treatment is performed on the yarn by heating the drawing roller, and the polyamide fiber can be produced by winding it up with a winder (winding device).

The polyamide fiber of the present invention has a sulfuric acid relative viscosity of 2.0 to 4.0 of the polyamide polymer used for melt spinning, and the melting temperature of the melt spinning is higher than 20°C and lower than 85°C with respect to the melting point of the polyamide. , In order to keep the atmosphere temperature under detention at a high temperature, the heater temperature of the steam seal should be set to 200℃ or higher, the starting distance of cooling should be 30 to 170 mm to slowly cool the polyamide polymer from the discharge hole under the detention, and the take-up roller It can be manufactured by setting the speed of 1300 to 2400 m/min, the draw ratio of 1.7 to 3.0 times, and the winding speed of 3000 m/min or more and 4500 m/min or less of spinning conditions.

In particular, when the take-up roller is taken out in a low-speed region (1300 to 2400 m/min), orientation relaxation before stretching proceeds, and appropriate orientation and crystallization proceed during stretching. Further, it is preferable to heat-treat the stretching roller as a heating roller, and the heat treatment temperature is preferably 150 to 190°C. It is preferable that the relaxation rate between the heating roller and the winder is 0 to 2.0%. This is because in such a range, by controlling the tension during heat treatment, proper orientation and crystallization proceeds, and it becomes possible to control the rigid amorphous amount of the polyamide fiber to 40% or more.

In addition, in order to slowly cool the polyamide polymer from the discharge hole under the detention, the amount of rigid amorphous can be made higher by promoting orientation relaxation with a cooling start distance of 30 to 170 mm. More preferably, a heating tube is provided between the spinneret and the thread cooling device, and the amount of stiffness amorphous can be further increased by promoting the relaxation of orientation by setting the atmosphere temperature in the cylinder in the range of 100 to 300°C.

The fabric of the present invention can be referred to as a fabric by woven by a commercial method. The warp fibers are placed side by side on a krill and wound around a beam, and the fibers wound around the beam are then glued and dried to prepare warp. Subsequently, the warp is passed through the lead of the loom, and the weft is driven into the fabric. There are types of looms such as shuttle looms, air jet room looms, water jet room looms, rapier looms, and gripper shuttle looms, but any loom may be manufactured. In addition, there are several weaving structures, such as a flat structure, a quarter structure (twill), and a runner structure (satin), depending on the purpose of the weft.

The knitted fabric of the present invention can be referred to as a knitted fabric by knitting by a commercial method. There are types of knitting machines such as flat knitting machines, circular knitting machines, and warp knitting machines, but any knitting machine may be used. In addition, by knitting, there are several knitting structures such as flat knitting, rib knitting, pearl knitting, interlock (double-sided knitting) and warp knitting in the case of circular and flat knitting, such as atlas structure, denby structure, and cord structure. You can choose either.

In addition, it is necessary to use at least a part of the polyamide fiber of the present invention for the yarn used for the woven fabric. Other fibers are not particularly limited, such as natural fibers and chemical fibers.

Subsequently, dyeing is performed by a known method. In general, it is finished by refining, intermediate set, dyeing, and finishing set. There are various types of dyeing machines such as liquid dyeing machine, jigger dyeing machine, beam dyeing machine, and Wins dyeing machine, but you may dye with any dyeing machine. Polyamide dyes include disperse dyes, acid dyes, complex dyes, acid mordant dyes, reactive dyes, etc., but from the viewpoint of overall fastness such as dyeing, washing, sunlight, friction, and from the viewpoint of leveling properties, acid dyes, A metal complex salt acidic dye can be preferably used, and it is carried out by treating at a temperature of 90°C or higher for about 30 to 90 minutes. Further, in order to prevent color loss after dyeing, a fixing treatment with synthetic tannin, tannin/soil tin, or the like may be performed.

After dyeing, functional processing for the purpose of imparting functions may be performed. For example, in the case of a down jacket base fabric, calendering and water repelling are performed as a function imparting function. The calendering process may be performed on one side or both sides, and may be performed at any stage of the dyeing process, but is preferably carried out after the dyeing process. In the water-repellent processing, a water-repellent agent such as paraffin-based, fluororesin-based, or silicone-based resin is used, and resin processing or the like is performed by pad, coating, absorption, lamination, or the like.

The polyamide fibers and woven fabrics of the present invention are not limited in their use, but can be used as various medical products such as sports, casual wear, women's and men's medical care, and inner wear such as windbreaker, down jacket, colp wear, rainwear, etc. I can.

Example

The present invention will be described in detail with examples. In addition, the following method was used as a measurement method in an Example.

A. Sulfuric acid relative viscosity

0.25 g of a sample was dissolved to 1 g with respect to 100 ml of sulfuric acid having a concentration of 98% by weight, and the flow time (T1) at 25°C was measured using an Oswald type viscometer. Subsequently, the flow time (T2) of only sulfuric acid having a concentration of 98% by weight was measured. The ratio of T1 to T2, that is, T1/T2, was referred to as the relative viscosity of sulfuric acid.

B. Total fineness

The total fineness was determined as the total fineness (dtex) by measuring the quantitative fineness with a predetermined load of 0.045 cN/dtex according to the JIS L 1013 (2010) 8.3.1A method. The single fiber fineness is a value obtained by dividing the total fineness by the number of filaments as single fiber fineness (dtex).

The sample is wound 200 times in a detector with a frame circumference of 1.125m, dried in a hot air dryer (10 ⁵ ± 2℃ × 60 minutes), and then the weight of the skein is measured by means of a measure and the fineness is multiplied by the process moisture content. Calculated. The measurement was performed 4 times, and the average value was called fineness. In addition, a value returned by dividing the obtained fineness by the number of filaments was referred to as single fiber fineness.

C. Strength and elongation

Using the "TENSILON" UCT-100 manufactured by Orientec Corporation as a measuring instrument, it was measured under the constant-speed elongation conditions shown in JIS L1013 (enacted in 1953, revised in 2010 (chemical fiber filament yarn test method)). The strength was obtained from the elongation of the point showing the maximum strength in the curve, and the strength was the value obtained by dividing the maximum strength by the fineness, and the measurement was performed 10 times, and the average value was called strength and elongation.

D. Stiffness amorphous amount

The rigid amorphous amount was measured using Q1000 manufactured by TA Instruments as a measuring instrument. The difference between the heat of fusion and the heat of cold crystallization (ΔHm-ΔHc) obtained from the differential scanning calorimetry measurement (hereinafter, abbreviated as DSC), the specific heat difference (ΔCp) obtained from the temperature modulated DSC measurement, and the polyamide is 100% determined (completely Crystalline) and the theoretical value of 100% amorphous polyamide (completely amorphous). Here, ΔHm ⁰ is the amount of heat of melting of the polyamide (complete crystal). In addition, ΔCp ⁰ is the specific heat difference before and after the glass transition temperature (Tg) of the polyamide (completely amorphous).

The crystallinity (Xc) and the movable amorphous amount (Xma) were calculated based on the formulas (1) and (2). Further, the rigid amorphous amount (Xra) was calculated from the equation (3). In addition, the rigidity amorphous amount was calculated from the average value of these measurements twice.

(1) Xc(%) = (ΔHm-ΔHc)/ΔHm ⁰ ×100

(2) Xma(%) = ΔCp/ΔCp ⁰ ×100

(3) Xra(%) = 100-(Xc+Xma).

The measurement conditions of DSC and temperature modulated DSC are shown below.

(DSC measurement)

Measuring device: TA Instruments Q1000

Data processing: Universal Analysis 2000 by TA Instruments

Atmosphere: Nitrogen (50mL/min)

Sample amount: about 10 mg

Sample container: standard container made of aluminum

Temperature and calorie calibration: high purity indium (Tm=156.61℃, ΔHm=28.71J/g)

Temperature range: about -50 to 300℃

Temperature rise rate: 10°C/min 1st temperature rise process (first run)

(Temperature Modulated DSC Measurement)

Device: Q1000 made by TA Instruments

Data processing: Universal Analysis 2000 by TA Instruments

Atmosphere: Nitrogen (50mL/min)

Sample amount: about 5 mg

Sample container: standard container made of aluminum

Temperature and calorie calibration: high purity indium (Tm=156.61℃, ΔHm=28.71J/g)

Temperature range: about -50~210℃

Temperature rise rate: 2℃/min

E. Amino end group amount

1 g of a dried polyamide chip or fiber sample was accurately weighed, dissolved in 25 ml of a phenol-ethanol mixed solvent (83.5:16.5, volume ratio), and then the amount of amino terminal groups was determined by neutralization titration using 0.02N hydrochloric acid aqueous solution. Measured. In addition, the numerical value of the amount of amino terminal groups in the present specification is expressed as x10 ^-5 mol/g.

F. Titanium oxide content

The crucible is baked in an electric furnace at 800° C., cooled, and then accurately weighed (A1). A completely dried sample is measured and taken in this crucible (S), and the sample is carbonized while heating in an electric furnace. Samples are made from raw chips or fiber samples. Subsequently, the crucible is baked in an electric furnace at a constant temperature of 800° C., followed by cooling and regularization (A2). From the result of measuring in this way, the content rate of titanium oxide was calculated|required by the method shown below.

Titanium oxide content (%) = (A2-A1)/S×100.

G. Fabrication (preparation of samples in the measurement of items H. and I.)

Cylindrical knitting paper was created with two yarns using the cylindrical knitting machine NE450W made by Eiko Industrial Co., Ltd. After scouring the obtained cylindrical knitted fabric, it was intermediately set under conditions of 170°C x 1 minute, dyed and fixed under the conditions of 100°C x 30 minutes with an alloy dye (lanasyn black M-DL 1705% owf), and then 160°C. The set was performed after finishing under the conditions of x 1 minute.

H. Color development

The fabric obtained in the above G item was calculated from the average value obtained by measuring the L value three times using a color meter SM-T manufactured by Suga Test Instruments Co., Ltd. The L value relates to the brightness of an optical parameter, and the larger the L value is, the more white it becomes. It is preferable that the L value is small for evaluation of the dark color development property.

About the result judgment of the L value, C or more was taken as the pass based on the range shown below.

A: less than 13

B: 13 or more to less than 16

C: 16 or more to less than 19

D: 19 or more.

I. Fastness

The fabric obtained in the above item G was measured by the A-2 method shown in JIS L0844 (washing fastness test method), and a grade judgment was performed on discoloration. For the result judgment, grade 3 or higher was regarded as the pass.

(Example 1)

As a polyamide, the amount of the amino terminal group was adjusted to 9.0×10 ^-5 mol/g, and an 85% aqueous solution of ε-caprolactam was 175 kg, hexamethylenediamine 460 g, and titanium oxide in a polymerization reactor having a capacity of 200 liters. 12.5 kg of 20% aqueous solution was added and dissolved to obtain a uniform solution. After sealing the inside of the polymerization reaction apparatus with nitrogen, the temperature was raised in 1 hour until the internal pressure of the reaction apparatus became 0.98 MPa, and the temperature was continuously raised to 250°C while maintaining this pressure. After reaching 250° C., pressure was released over 40 minutes until it became atmospheric pressure. After that, after holding|maintaining at 250 degreeC for 50 minutes at atmospheric pressure, the polymer was discharged|discharged, and it cooled/cut|cut|cut and it was made into a pellet shape. The unreacted component in this pellet was extracted with hot water at 98 degreeC of 20 times amount with respect to the pellet, and it dried with a vacuum dryer. The sulfuric acid relative viscosity (abbreviated as ηr) of the obtained polyamide chip was 2.6, the amount of amino terminal groups was 9.0×10 ^-5 mol/g, The titanium oxide content was 1.85% by weight.

The polyamide chip obtained as described above was melted at a spinning temperature of 260°C, and a circular hole having a discharge hole diameter of 0.20 mm and a hole length of 0.50 mm was discharged from a spinneret having 68 holes. A heating tube with a length of 50 mm is placed between the spinneret and the thread cooling device, and the cooling start distance is set to 169 mm, and the thread passed through the cylinder set at 300°C in the upper layer and 150°C in the lower layer is cooled by a cooling device. After cooling and solidification by blowing and lubricating with a lubrication device, fastening is provided with a fastening nozzle device, and stretched at 2.1 times the draw ratio between the take-up roller and the draw roller with a surface temperature of 155°C, and relaxes between the draw roller and the winder. It was wound with a winder with a rate of 1.0% and a winding speed of 4000 m/min to obtain a polyamide fiber of 44 dtex-34 filament.

About the obtained polyamide fiber, strength, elongation, rigid amorphous amount, amount of amino terminal groups, and amount of titanium oxide were measured, and dyeing property and fastness were evaluated with a cylindrical knitted paper. The results are shown in Table 1.

(Example 2)

A polyamide chip was obtained in the same manner as in Example 1, except that the amount of hexamethylenediamine was adjusted so that the amount of amino terminal groups of the polyamide was 7.7 mol/g.

Table 1 shows the results of performing the same measurement and evaluation of the polyamide fibers obtained in the same spinning conditions as in Example 1 on the polyamide chips obtained as described above.

(Example 3)

A polyamide chip was obtained in the same manner as in Example 1, except that the amount of hexamethylenediamine and the polymerization time were adjusted so that ηr of the polyamide was 3.3 and the amount of amino terminal groups was 7.9 mol/g.

Table 1 shows the results of performing the same measurement and evaluation of the polyamide fibers obtained under the same spinning conditions as in Example 1, except that the polyamide chips obtained as described above were set at 2.0 times the draw ratio and 1.6% relaxation ratio.

(Example 4)

A polyamide chip was obtained in the same manner as in Example 1, except that the amount of hexamethylenediamine was adjusted so that the amount of amino terminal groups of the polyamide was 7.0 mol/g.

Table 1 shows the results of performing the same measurement and evaluation of the polyamide fibers obtained under the same spinning conditions as in Example 1, except that the polyamide chips obtained as described above were set at 1.9 times the draw ratio and 0.8% relaxation ratio.

(Example 5)

Table 1 shows the results of performing the same measurement and evaluation under the same conditions as in Example 1, except that the relaxation rate was 1.5%.

(Example 6)

Table 1 shows the results of performing the same measurement and evaluation under the same conditions as in Example 1, except that the relaxation rate was 2.0%.

(Example 7)

In the same spinning conditions as in Example 1, except that the addition amount of titanium oxide was adjusted so that the titanium oxide content of the polyamide was 0.40% by weight, except that the polycaproamide obtained by the production method as in Example 1 was 1.8 times the draw ratio. Table 2 shows the results of performing the same measurement and evaluation of the obtained polyamide fibers.

(Example 8)

In the same spinning conditions as in Example 1, except that the addition amount of titanium oxide was adjusted so that the titanium oxide content of the polyamide was 5.00% by weight, except that the polycaproamide obtained by the production method as in Example 1 was 2.5 times the draw ratio. Table 2 shows the results of performing the same measurement and evaluation of the obtained polyamide fibers.

(Example 9)

In the same spinning conditions as in Example 1, except that the addition amount of titanium oxide was adjusted so that the titanium oxide content of the polyamide was 0.10% by weight, except that the polycaproamide obtained by the same production method as in Example 1 was made 1.7 times the draw ratio. Table 2 shows the results of performing the same measurement and evaluation of the obtained polyamide fibers.

(Example 10)

In the same spinning conditions as in Example 1, except that the addition amount of titanium oxide was adjusted so that the titanium oxide content of the polyamide was 9.00% by weight, except that the polycaproamide obtained by the production method as in Example 1 was made 2.8 times the draw ratio. Table 2 shows the results of performing the same measurement and evaluation of the obtained polyamide fibers.

(Example 11)

300 kg of a 50% aqueous solution of an equimolar salt of adipic acid and hexamethylenediamine, 575 g of hexamethylenediamine, and 12.5 kg of a 20% aqueous solution of titanium oxide were added and dissolved in a polymerization reactor having a capacity of 200 L to obtain a homogeneous solution. After the inside of the polymerization reaction apparatus was sealed with nitrogen, the internal pressure of the reaction apparatus was maintained at 0.2 MPa, and the water in the solution was concentrated until 85 wt%. Thereafter, the temperature was raised in 1 hour until the internal pressure of the reaction apparatus became 1.7 MPa, and the temperature was continued to rise to 255°C while maintaining this pressure. After reaching 255°C, pressure was released over 60 minutes until the pressure reached atmospheric pressure. After that, the pressure in the cylinder was reduced to -13 kPa and held for 30 minutes to complete the polycondensation reaction. The polymer was discharged and cooled/cut to obtain a pellet shape. Ηr of the obtained polyamide chip was 2.7, the amount of amino terminal groups was 9.0×10 ^-5 mol/g, and the titanium oxide content was 1.85% by weight.

Table 2 shows the results of performing the same measurement and evaluation of the polyamide fibers obtained under the same spinning conditions as in Example 1, except that the polyamide chips obtained as described above were melted at a spinning temperature of 290°C.

(Comparative Example 1)

Table 3 shows the results of performing the same measurement and evaluation under the same conditions as in Example 1, except that the draw ratio was 2.4 times and the relaxation rate was 3.0%.

(Comparative Example 2)

It was obtained in the same manner as in Example 1, except that the amount of hexamethylenediamine was adjusted so that the amount of amino terminal groups of the polyamide was 5.1 × 10 ^-5 mol/g. Table 3 shows the results of performing the same measurement and evaluation of polycaproamide under the same conditions as in Example 1.

(Comparative Example 3)

Table shows the results of performing the same measurement and evaluation under the same conditions as in Example 1, except that the take-up roller speed was 4545 m/min, the draw ratio was 1.0 times, the relaxation rate was 1.0%, and the take-up speed was 4500 m/min without heating the draw roller. It is shown in 3.

(Comparative Example 4)

A polyamide chip was obtained in the same manner as in Example 1, except that the amount of hexamethylenediamine was adjusted so that the amount of amino terminal groups of the polyamide was 7.5×10 ^-5 mol/gmol/g. Table 3 shows the results of performing the same measurement and evaluation under the same conditions as in Example 1, except that polycaproamide was taken up at a roller speed of 3550 m/min, a draw ratio of 1.3 times, a relaxation rate of 2.5%, and a take-up speed of 4500 m/min. Show.

(Industrial availability)

Since the polyamide fiber of the present invention has good color development and excellent fastness, it can be used as various medical products such as sports, casual wear, women's and men's medicine, and inner wear.

Claims (5)

A polyamide fiber containing an aliphatic polyamide as a main component, wherein the amount of amino terminal groups in the aliphatic polyamide is 7.0×10 ^-5 mol/g or more and 10.0×10 ^-5 mol/g or less, and is required for polyamide fiber. Polyamide fiber with 40% or more of rigid amorphous amount. The method of claim 1,
Polyamide fibers containing 0.1 to 10.0% by weight of titanium oxide based on the total amount of fibers. The method according to claim 1 or 2,
Polyamide fiber with a total fineness of 5 to 235 dtex. A medical woven fabric containing the polyamide fiber according to any one of claims 1 to 3. A method for producing a polyamide fiber in which a raw material for a polyamide resin is melted, the polyamide resin is discharged from a detent, cooled and solidified to form a yarn, and the yarn is stretched and heat treated and then wound,
The polyamide resin raw material contains an aliphatic polyamide, and the amount of amino terminal groups in the aliphatic polyamide is 7.0×10 ^-5 mol/g or more and 10.0×10 ^-5 mol/g or less, and the following (a) to ( A method for producing a polyamide fiber comprising the step d).
(a) The discharge process in which the take-up speed is 1300m/min to 2400m/min.
(b) A stretching step in which the thread is stretched by the draft ratio of the take-up roller and the stretching roller, and the temperature of the stretching roller is 150 to 190°C and the draw ratio is 1.7 to 3.0 times.
(c) After the stretching treatment, the thread is relaxed between the stretching roller and the take-up roller, and the relaxation treatment step is 0 to 2.0%.
(d) A winding process in which the winding speed is 3000 to 4500 m/min.