KR101550960B1 - Hygroscopic fibre, and manufacturing method for same - Google Patents

Abstract

The present invention relates to a hygroscopic fiber having a? MD of 3.0% or more, which is a fiber comprising a polyamide 56 resin. Also disclosed is a method for producing a polyamide 56 fiber by a direct radial stretching method in which a polyamide 56 fiber discharged from a spinneret is cooled and solidified by cooling wind, (1) to (2). (2) The product of the draw speed and the draw ratio is 3900 or more and 4500 or less
The present invention provides a hygroscopic synthetic fiber having high moisture absorptivity and a high added value without deteriorating the properties of polyamide such as strength, chemical resistance and heat resistance, and a process for producing the same.

Description

HYGROSCOPIC FIBER, AND MANUFACTURING METHOD FOR SAME [0002]

The present invention relates to highly hygroscopic fibers comprising a polyamide 56 resin.

BACKGROUND OF THE INVENTION Synthetic fibers including thermoplastic resins such as polyamide and polyester are widely used for medical (clothing) applications and industrial applications because of their excellent strength, chemical resistance and heat resistance.

In particular, polyamide fibers are widely used for innerwear, sportswear and the like, taking advantage of their unique softness, high tensile strength, coloring property during dyeing, and high heat resistance.

[Prior Art Literature]

[Patent Literature]

Patent Document 1 proposes a method of imparting a moisture absorbent to the surface of a fiber in a post-processing step of forming a fiber of polyamide.

Further, a method of imparting hygroscopicity to fibers by making the polyamide resin itself hydrophilic is also attempted. For example, Patent Document 2 proposes a method of producing a fiber by using a polyamide resin obtained by copolymerizing a hydrophilic component such as polyoxyalkylene glycol or the like.

Patent Document 3 proposes a method of ensuring compatibility between moisture absorption performance and mechanical properties by making the structure of the fiber a core shell structure in which a highly hygroscopic thermoplastic resin is used as a core portion and a thermoplastic resin having excellent mechanical properties is used as a shell portion.

In addition to the chemical modification of these fiber-forming thermoplastic resins, physical modification, that is, elutable components are mixed, the eluted components are extracted after fiber formation to form fibrils and voids, and the hygroscopic surface area is increased to increase the moisture absorption rate A method aimed at increasing the moisture absorption rate has been proposed. For example, in Patent Document 4, a blend composite of a fiber-forming thermoplastic resin compatible with an alcohol-soluble polyamide and an alcohol-soluble polyamide is melt-spun, and a part of the alcohol-soluble polyamide is eluted therefrom, A method of obtaining hygroscopic fibers has been proposed.

A method of adding a hydrophilic compound to a polyamide fiber has been generally studied most. For example, Patent Document 1 proposes a method of improving moisture absorption performance by blending polyvinylpyrrolidone as a hydrophilic polymer with polyamide and spinning it.

(Patent Document 1) Japanese Patent Laid-Open No. 9-188917

(Patent Document 2) Japanese Patent Laid-Open Publication No. 5-209316

(Patent Document 3) JP-A-3-213519

(Patent Document 4) Japanese Unexamined Patent Publication (Kokai) No. 60-246818

Conventional polyamide fibers have lower hygroscopicity than natural fibers, so they are subject to sweating or tackiness due to sweating from the skin, resulting in deterioration of the natural fibers in terms of comfort.

Thus, there has been proposed a method of imparting a moisture absorbent to the fiber surface in the post-processing step of forming polyamide fibers.

However, when durability against washing is deteriorated and a large amount of a moisture absorber is added in order to obtain high hygroscopicity, there is a disadvantage in that the surface of the fiber is wetted with moisture to cause discomfort.

According to the method of Patent Document 2, in order to achieve a sufficient hygroscopicity, it is necessary to increase the copolymerization ratio, while the mechanical properties such as strength and elongation of the yarn are significantly impaired, Is not obtained.

The composite fiber of Patent Document 3 has a disadvantage in that the cost is increased because the production apparatus is complicated. From the difference in the absorption ability of the polymer used for the core portion and the shell portion, the hygroscopic resin of the core portion becomes water There is a drawback that the polymer surface of the core portion is eluted due to generation of cracks on the fiber surface.

In the method according to Patent Document 4, if the elution component is small, a sufficient hygroscopic property can not be obtained. Conversely, if the elution component is large, the physical properties such as the strength of the fiber become insufficient and whitening or fibrillation of the fiber product occurs And it is difficult to satisfy both the moisture absorption performance and the physical properties.

The method of Patent Document 1 is superior as a hygroscopic fiber, but polyvinylpyrrolidone is added as a polyamide based on polyamide 6, and therefore, for example, in recent years, wearing a tight-fitting T-shirt or the like as a fashion trend As the demand for mold bras that do not affect the outerwear with the increasing number of women increases, the heat resistance to mold processing was not sufficient. Further, when polyvinylpyrrolidone is added based on polyamide 66 having a high melting point, there is a problem that the spinning temperature of polyamide 66 is high and polyvinylpyrrolidone is thermally degraded and can not be stably radiated.

As described above, there has been a demand for a yarn having a hygroscopic property that does not deteriorate the properties of polyamide fibers and is not inferior to natural fibers.

It is an object of the present invention to provide a hygroscopic synthetic fiber having a high moisture absorptivity and a high added value without impairing the properties of polyamide such as strength, chemical resistance and heat resistance by overcoming the problems of the prior art.

The above object of the present invention is achieved by a hygroscopic fiber having a? MD of 3.0% or more, which is a fiber comprising a polyamide 56 resin.

It is also an object of the present invention to provide a polyamide 56 fiber which is obtained by cooling and solidifying polyamide 56 fibers discharged from a spinneret by cooling air, (1) to (2), wherein the hygroscopic fiber is produced by a method of producing hygroscopic fibers satisfying the following conditions (1) to (2).

(1) The speed at which the wire is discharged is 14 m / min or more and 30 m / min or less

(2) The product of the draw speed and the draw ratio is 3900 or more and 4500 or less

The object of the present invention is also achieved by a fiber product made using the hygroscopic fiber.

The object of the invention is also achieved by a fiber structure comprising said textile product.

Absorbent fibers of the present invention it is preferred that the birefringence of the fiber at least 30 × 10 ^-3 40 × 10 ^-3 or less. It is preferable that the fiber product of the present invention is a fiber product using the hygroscopic fiber and includes a molded part by molding.

In the fibrous structure of the present invention, it is preferable that the fibrous structure is innerwear.

According to the present invention, it is possible to obtain a hygroscopic synthetic fiber having high moisture absorptivity and high added value without impairing the properties of polyamide such as strength, chemical resistance and heat resistance.

1 is a schematic view showing an example of a process for producing a synthetic fiber according to the present invention.

The polyamide 56 fiber of the present invention is a fiber comprising a polyamide 56 resin having 1,5-diaminopentane unit and adipic acid unit as main constituent units.

The polyamide 56 fibers of the present invention are preferably composed of 1,5-diaminopentane units using biomass because they are excellent in environmental adaptability. It is preferable that at least 50% of the 1,5-diaminopentane units constituting the polyamide 56 contain 1,5-diaminopentane obtained by using the biomass in view of superior environmental adaptability. , More preferably at least 75%, and most preferably at least 100%.

The polyamide 56 in the present invention is preferably a polymer having 98% sulfuric acid relative viscosity of 2.4 or more and 2.6 or less in order to effectively exhibit the effect of the present invention. When the relative viscosity of 98% sulfuric acid is in the above-mentioned preferable range, it becomes easy to obtain sufficient strength when made into a fiber, and on the other hand, the degree of crystallization when formed into a fiber is appropriate and sufficient hygroscopicity can be obtained, The extrusion pressure and the aging speed of the extrusion pressure are appropriate, so that it is unnecessary to add excess to the production facility or to shorten the exchange period of the detention, and high productivity is maintained.

Here, the 98% sulfuric acid relative viscosity refers to a value measured at 25 ° C using an Oswald viscometer after dissolving 25 g of the fibers in 25 ml of 98% sulfuric acid.

The polyamide 56 in the present invention may be copolymerized or mixed with the second and third components in addition to the main component within a range not deviating from the object of the present invention. The copolymerization component may include, for example, a structural unit derived from an aliphatic carboxylic acid, an alicyclic dicarboxylic acid, or an aromatic dicarboxylic acid.

Also, aliphatic diamines such as ethylenediamine and cyclohexanediamine, alicyclic diamines such as bis- (4-aminocyclohexyl) methane, aromatic diamines such as xylylenediamine, 6-aminocaproic acid, , Amino acid such as 12-aminododecanoic acid and p-aminomethylbenzoic acid, and lactam such as? -Caprolactam and? -Laurolactam.

The polyamide 56 in the present invention may contain various additives such as a matting agent, a flame retardant, an antioxidant, an ultraviolet absorber, an infrared absorber, a nucleating agent, a fluorescent whitening agent and an antistatic agent in an amount of 0.001 to 10 wt% %, As required.

The cross-sectional shape of the short fibers of the polyamide 56 fibers of the present invention can adopt not only a round cross section, but also various cross-sectional shapes such as flat, Y, T, hollow, filament, A Y-shaped, a T-shaped, or a sperm-like cross-section is preferable in order to generate a gap between adjacent filaments and to exhibit absorbency by capillary phenomenon.

The moisture absorptive and desorptive parameter DELTA MR exhibiting a moisture absorbing property is preferably higher in order to provide better comfort at the time of wearing. Here, ΔMR is an index for obtaining comfort by releasing moisture in the clothes when wearing clothes, and is a temperature in a garment represented by 30 ° C. × 90% RH when subjected to light to heavy work or light to heavy work and , And the moisture absorption rate of the outside air temperature and humidity typified by 20 占 폚 占 65% RH. In the present invention, this? MR is used as a parameter as a measure of the hygroscopicity performance evaluation. The larger the? MR, the higher the moisture absorptive and desorptive ability, and the better the comfort at the time of wearing. Generally, polyamide fibers such as polyamide 6 and polyamide 66 have an? MR of about 1.5 to 2.0. On the other hand, the polyamide fiber of the present invention has a moisture absorbing and desorptive property with a DELTA MR of 3.0% or more. If the DELTA MR is less than 3.0%, the moisture absorbing and desorbing performance of the polyamide 6 or the polyamide 66 is equivalent to that of ordinary polyamide 6 or polyamide 66, and the comfort at the time of wearing is not high. There is no upper limit, but if it is too large, a large difference does not occur on the body, so it is sufficient that? MR is about 20%.

The moisture absorptive and desorptive ability of the polyamide fiber greatly depends on the crystal structure in the fiber. There are two cases of moisture absorption of the polyamide fibers, that is, when the moisture is bonded to the amide group of the polyamide, and when the polyamide fibers are introduced into the non-crystalline phase where the polyamide molecular chains in the fiber are randomly present, , The reversible moisture absorptive and desorptive ability depends largely on the ratio of the amorphous portion in the fiber. Therefore, in order to improve the DELTA MR of the polyamide fibers, it is important to increase the proportion of the amorphous portion within a range that does not impair spinnability and yarn quality.

Generally, the birefringence of crystalline synthetic fibers is large in fibers in which molecular chains are oriented and becomes small in fibers in which orientation is not progressed. The orientation of the molecular chains is an important parameter because it greatly affects the absorption rate of the fibers as described below. That is, there are two cases of moisture absorption of the polyamide fibers, that is, when the moisture binds to the amide group of the polyamide, and when the polyamide fibers are introduced into the non-crystalline region where the polyamide molecular chains in the fibers are randomly present. In particular, the ratio of the amorphous portion in the fiber greatly affects the? MR value.

In the polyamide fiber, the proportion of the crystalline portion is large, the proportion of the non-crystal portion capable of retaining moisture is small, and in the case where the crystalline portion is large, moisture of the fiber surface can not reach the vicinity of the amide group in the polyamide fiber.

The orientation of the molecular chains can be represented by birefringence. When the birefringence is large, the moisture absorption rate tends to become large. If the moisture absorption rate is too large, the radiation oil and moisture in the air are excessively absorbed. As a result, And the fluctuation of the fiber structure becomes large, and the quality is deteriorated. Further, when the birefringence is reduced, orientation of the molecular chains in the fibers is promoted to crystallization, and the moisture absorption rate tends to decrease.

In the polyamide fiber of the present invention, it is preferable that the birefringence less than 30 × 10 ^-3 or more and 40 × 10 ^-3, by the polyamide without impairing the high spinning work efficiency and the yarn quality of the fibers 56 in such a range A polyamide 56 fiber having moisture absorptive and desorptive properties can be obtained.

In the polyamide fiber of the present invention, by setting the DELTA MR within the above-mentioned range, it is possible to obtain a medical treatment with good comfort at the time of wearing.

The polyamide fiber of the present invention can be produced by the following method.

An example of a method of stretching a polyamide fiber of the present invention will be described concretely with reference to Fig. 1 is a schematic view showing an example of a process for producing a synthetic fiber according to the present invention.

The molten polyamide is metered and transported by a gear pump, discharged from the spinneret 2, cooled by a yarn cooler 3 such as a chimney to cool the yarn to room temperature, And is entangled in the first fluid mixing nozzle device 5 to pass through the draw roller 6 and the draw roller 7. At this time, the draw roller 6 and the draw roller 7 It is stretched according to the ratio of the main speed. Further, the yarn is thermally set by a stretching roller 7 and wound by a winder (winding device) 8.

In the method for producing a polyamide fiber of the present invention, the wire discharge linear velocity is 14 m / min to 30 m / min. Here, the nailing discharge linear velocity is a value obtained by dividing the discharge volume per unit time of the polymer in the nipping hole that discharges the nested yarn by the nipping hole area, and is a parameter that determines the degree of orientation of the yarn-like polymer discharged from the nipping hole. When the take-out line speed is low, the take-up roller speed and the speed ratio of the take-up roller 6 become large when the take-up roller 6 is pulled by the take-up roller 6 and an excessive stretching tension is applied to the filament during take- It can not be stabilized. If the take-off wire speed is too high, the fiber is pulled by the take-up roller 6, and the orientation of the fiber after being stretched by the stretching roller 7 continues too much, resulting in a fiber having a low moisture absorption rate.

The product of the pulling speed (m / min) of the yarn pulled by the pulling roller 6 and the drawing magnification which is the value of the main speed ratio of the pulling roller 6 to the drawing roller 7 is 3900 to 4500 To set the condition. This figure shows that the polymer discharged from the spinneret has a total elongation amount elongated from the nip discharge line speed to the main speed of the take-up roller 6 and from the main speed of the draw roller 6 to the main speed of the elongating roller 7 If this value is too small, the degree of orientation of the fibers is low, and the fiber becomes too large a moisture absorbing rate, so that it absorbs too much of the radiation oil and moisture in the air, and as a result, the yarn becomes swollen and can not be stably radiated. If this value is too large, the orientation of the fibers will proceed too much, resulting in a fiber having a low moisture absorptivity.

It is preferable that the radial emulsion imparted by the oil feed device 4 is a non-hydrodynamic emulsion. When the non-hydrotreated emulsion is added, there is no possibility that the water is absorbed by the polyamide 56 during the emulsion application, so that swelling of the polyamide does not occur, and therefore the fiber length fluctuation during the production is not present, and stable winding is possible.

The polyamide fibers of the present invention preferably have a tensile strength of 3.5 cN / dtex or more. By setting the tensile strength of the fibers to 3.5 cN / dtex or more, practical strength of medical textile products such as innerwear, which is the main use of polyamide 56 fiber products, can be realized. More preferably 4.0 cN / dtex or more.

The polyamide fiber of the present invention preferably has an elongation of 35% or more. By setting the elongation of the fibers to 35% or more, the processability in high-order processes such as weaving, knitting, and false twisting is improved. And more preferably 40 to 65%.

The fineness of the polyamide fibers of the present invention is preferably not more than 100 dtex, more preferably not more than 60 dtex in terms of the thickness when processed into a fiber product. The single fiber fineness is preferably 4.0 dtex or less, more preferably 2.0 dtex or less in terms of softness when processed into a fiber product.

The structure of the hygroscopic fiber obtained as described above is not limited to those described above, and may be either filament or staple, and may be selected depending on the application. The form of the fiber product can be selected according to the purpose such as a fabric, a knitted fabric, and a nonwoven fabric, and includes medical treatment. It is processed after knitting by a usual method and sewed to various medical products such as innerwear, pantyhose, and tights. Among them, the fiber product of the present invention is preferably a fiber product including a molded part by performing mold processing in view of combinability of heat resistance and water absorbability, which were difficult to achieve in conventional polyamide fibers. Specifically, the fabric structure of the present invention is fabricated by using innerwear or a mold processing section such as a cup, panty, girdle, waist or hip portion of a brassiere, such as a concave portion, a convex portion, As an innerwear.

Mold processing is a process in which a fiber product such as a woven fabric, a woven fabric, or a nonwoven fabric is put into a mold (metal mold), heat treatment is applied, and rounding is applied. As the heat treatment conditions, the surface temperature of the mold is usually 160 to 230 占 폚, preferably 170 to 220 占 폚, and more preferably 190 to 200 占 폚. The treatment time is preferably 0.5 to 3 minutes.

<Examples>

The present invention will be described in detail in the following examples. In the measurement methods in Examples, the following methods were used.

[How to measure]

A. Relative Viscosity of Sulfuric Acid

0.25 g of the sample was dissolved in an amount of 1 g per 100 ml of sulfuric acid having a concentration of 98% by weight, and the dropping time (T1) at 25 캜 was measured using an Oswald-type viscometer. Subsequently, the dropping time (T2) of sulfuric acid alone at a concentration of 98% by weight was measured. The ratio of T1 to T2, that is, T1 / T2, was defined as the relative relative viscosity of sulfuric acid.

B. Amino end group concentration

1 g of the sample was dissolved in 50 mL of a phenol / ethanol mixed solution (phenol / ethanol = 80/20) at 30 ° C with shaking to make a solution. The solution was neutralized with 0.02 N hydrochloric acid to obtain 0.02 N hydrochloric acid Respectively. Further, only the phenol / ethanol mixed solvent (the same amount as the above) is neutralized with 0.02N hydrochloric acid, and the amount of 0.02N hydrochloric acid consumed is obtained. From the difference, the amount of the amino terminal group per 1 g of the sample was determined.

C. Melting point (Tm)

10 mg of a sample was measured at a heating rate of 15 캜 / minute using a differential scanning calorimeter DSC-7 manufactured by Perkin-Elmer. The peak indicating the extreme value on the heat absorption side was determined as a melting peak, The temperature to be provided was defined as the melting point Tm (占 폚). When a plurality of extremum values exist, the extremum on the high temperature side is defined as the melting point.

D. Hygroscopicity (ΔMR)

The sample was weighed in a weighing bottle of about 1 to 2 g, held at 110 ° C for 2 hours, dried and weighed (W _O ), and then the material was held at 20 ° C and 65% relative humidity for 24 hours The weight is measured (W ₆₅ ). Then, after maintaining this at 30 DEG C and 90% relative humidity for 24 hours, the weight is measured ( _W90 ). Then, calculation is performed according to the following equation.

E. Birefringence

A birefringent index was measured and averaged by measuring the retardation and the diameter of two short staple fibers taken out from the fiber using a P0H-type polarizing microscope manufactured by Nippon Gohaku Kogyo Co., Ltd. and using white light as a light source.

F. Total fineness, monofilament fineness

10 revolutions were made with a calibrator around 1 m / circumference to prepare five loops of 10 turns and used as a sample for weight measurement. Likewise, a loop-like reel of 10 turns is manufactured in the same manner, and five loop-like reels are prepared by connecting the end portions of the reel so that they are not loosened. First, a total of 10 specimens were humidity-conditioned by leaving them in a load-free state at 25 ° C and RH 55% for 48 hours. Thereafter, under the same environment, the weight of the loop-like reel for weight measurement was measured to obtain an average value A (g). Next, the reel length of the loop upper reel for measuring the sample length was measured under the same conditions. The length of the reel was measured by attaching a loop upper reel for measuring the sample length to the hook and applying a load of 0.05 cN / dtex to the loop upper reel. When determining the load, the apparent fineness (= A (g) × 10,000 / 10) of the sample was used. The average length B (m) of the five sample lengths was obtained. Then, A was divided by B, and then the total fineness was determined by 10,000 times. The single fiber fineness was obtained by dividing the total fineness by the number of filaments.

G. Moldability

A stretchable fiber product was fixed in a relaxed state without loosening between two 2 cm fixtures cut out with a diameter of 15 cm and a hemispherical thermal steel ball having a diameter of 10 cm heated to a surface temperature of 200 캜 was pressed into a fiber product And pressurized to a depth of 10 cm. Immediately after 60 seconds, the hot iron ball is taken out. For the shape of the shaped lump-shaped part surface, the appearance before and after the processing is evaluated by the following criteria.

Good: Almost no change.

Inadequate: The surface is rough and not suitable as a commodity.

H. Wear assessment of absorbent stretch letters (knitted fabric)

A sample of a T-shirt sewn in a letter was knitted using the yarns of Example 1 and Comparative Example 1, Comparative Example 5, and Comparative Example 7, and sewn to fit the body. Subjects performed a jogging exercise of 12 Km / s for 5 minutes while these T-shirts were worn. Then, the stickiness of the subject's self-report upon self-report was evaluated based on the following evaluation criteria.

Excellent: Comfortable without feeling sticky

Good: No stickiness

Normal: sticky but tolerable

Insufficient: I feel sticky and uncomfortable.

Also, regarding the mood of the fiber product at the time of wearing, five subjects were self-reported and compared based on the following evaluation criteria.

Good: Soft, comfortable to wear

Poor: Stiff, stiff

I. Radiation stability

The radiation stability was evaluated by the number of spinning yarn breaks when two packages per one winder were wound for one hour under the spinning condition described later.

Good: less than 1 time

Poor: more than 2 times.

Production Example 1 (Production of polyamide 56 resin)

17.7 kg of adipic acid (manufactured by KAKKAI CO., LTD.) Was added in small amounts to an aqueous solution prepared by dissolving 12.3 kg of 1,5-diaminopentane in 30.0 kg of ion-exchanged water while stirring in an ice bath. In the vicinity of the neutralization point, 60.0 kg of a 50 wt% aqueous solution of 1,5-diaminopentane and adipic acid having a pH of 8.32 was prepared by warming in a water bath at 40 캜 and an internal temperature of 33 캜. 86.4 g of this aqueous solution, 1,5-diaminopentane and 28.2 g of a slurry in which titanium dioxide was dispersed in ion-exchanged water so as to have a concentration of 20% were mixed with a stirrer having double helical ribbon blades and a heating medium jacket L batch polymerization can. After thoroughly purging the polymerization can with nitrogen, heating was started at 260 캜 with stirring. The concentration was started at the time when the internal pressure reached 0.2 MPa (gauge pressure), and the degree of opening of the pressure-proof valve was adjusted so that the internal pressure of the polymerization can be kept constant. When the flow rate reached 24.7 kg, the pressure-proof valve was closed and the heating temperature was changed to 285 ° C. After the pressure in the can reached 1.7 MPa (gauge pressure), the pressure in the can was maintained. After the internal temperature reached 255 占 폚, the pressure was gradually reduced to atmospheric pressure over 50 minutes, then nitrogen gas was flowed at 5 L / min, and the inside of the can was blown for 15 minutes. Thereafter, a nitrogen pressure of 0.4 MPa (gauge pressure) was applied to the can, and the polymer discharged in a water bath was pelletized with a strand cutter. The obtained polyamide 56 resin had a sulfuric acid relative viscosity of 2.54 and an amino terminal group content of 2.77 × 10 ^-5 mol / g. The Tm measured by differential scanning calorimetry was 254 ° C.

Production Example 2 (Production of polyamide 66 resin)

A solution obtained by dissolving 30.0 kg of hexamethylenediammonium adipate (Rhodia) in 30.0 kg of ion-exchanged water, 140.4 g of adipic acid (manufactured by KAKKAI CO., LTD.), And 20% concentration of titanium dioxide 28.5 g of the slurry dispersed in ion-exchanged water was placed in an internal 80 L batch-type polymerization can equipped with a stirrer having double helical ribbon blades and a heating medium jacket. After thoroughly purging the polymerization can with nitrogen, heating was started at 260 캜 with stirring. The concentration was started at the time when the internal pressure reached 0.2 MPa (gauge pressure), and the degree of opening of the pressure-proof valve was adjusted so that the internal pressure of the polymerization can be kept constant. When the flow rate reached 24.7 kg, the pressure-proof valve was closed and the heating temperature was changed to 295 ° C. After the internal pressure of the can reaches 1.7 MPa (gauge pressure), the internal pressure of the can is maintained. After the internal temperature reached 255 DEG C, the pressure was gradually reduced to atmospheric pressure over a period of 50 minutes, then nitrogen gas was flowed at 5 L / min, and the inside of the can was blown for 10 minutes. Thereafter, a nitrogen pressure of 0.4 MPa (gauge pressure) was applied to the can, and the polymer discharged in a water bath was pelletized with a strand cutter. The obtained polyamide 66 resin had a sulfuric acid relative viscosity of 2.52 and an amino terminal group content of 2.88 x 10 ^-5 mol / g. The Tm measured by differential scanning calorimetry was 262 ° C.

Production Example 3 (Production of polyamide 6 resin)

Epsilon caprolactam containing 1% by weight of water was continuously fed in an amount of 30 kg / hr to a first polymerization reactor having a volume of 0.2 m ³ equipped with a thermometer and polymerization was carried out at a heating temperature of 270 ° C . From the lower part of the first polymerization reactor, the polymerization intermediate corresponding to the feed amount was discharged and fed to a second polymerization reactor having a volume of 0.08 m ³ equipped with a condenser and a thermometer. The heating temperature of the second polymerization reactor was set at 250 캜 and continuous polymerization was carried out under normal pressure to start discharging polycarbamide as a polymerization reaction product. From the point of time when 竜 -caprolactam of 1.5 times the capacity of the first polymerization reactor was fed, pellet tires were obtained to obtain a polycapramide-based product.

The resulting polycarbamide-based product was treated with hot water at 95 캜 for 16 hours to remove low molecular weight components. The obtained polyamide 6 resin had a sulfuric acid relative viscosity of 2.60 and an amino terminal group content of 5.10 x 10 ^-5 mol / g. The Tm measured with a differential scanning calorimeter was 230 deg.

[Example 1]

The melt-spinning, stretching and heat treatment were continuously carried out by using the direct radiation-drawing apparatus shown in Fig. 1 to obtain polyamide 56 fibers.

First, the polyamide 56 resin obtained in Production Example 1 was humidified to have a moisture content of 0.11%, and then introduced into a radiator. The polymer is then metered and discharged by the gear pump 1, guided to the spinneret 2 set at 290 ° C, and discharged to the spinneret 2 at 290 ° C. A round hole having a hole diameter of 0.25 mm and a hole length of 0.5 mm was discharged from the spinneret 2 having 24 holes.

At this time, the number of revolutions of the gear pump 1 was selected so that the total fineness of the obtained polyamide 56 fibers was 78 dtex, and the discharge amount was 31.2 g / min. Then, the yarn is cooled and solidified by the yarn cooler 3, the non-tropic emulsifier is lubricated by the oil feeder 4, then entangled in the first fluid entanglement nozzle device 5, The main speed of the stretching roller 6 was 2,066 m / min, the main speed of the stretching roller 7 of the second roll was 4,123 m / min, and the winding speed was 4,000 m / min. In the same manner as above, a 78 dtex 24 filament polyamide 56 fiber obtained by one step of spinning, stretching and heat treatment was obtained. Table 1 shows the physical properties of the obtained fibers. Further, a tricot letter was knitted from the obtained fibers, and mold processing evaluation was carried out. The evaluation results are shown in Table 1.

[Example 2]

Except that the discharge amount of the gear pump 1 was 34.1 g / min, the first roll main speed was 4,250 m / min, the second roll main speed was 4,463 m / min, and the winding speed was 4,400 m / min. Polyamide 56 fibers of 78 dtex and 24 filaments were obtained in the same manner. Table 1 shows the physical properties of the obtained fibers. Further, a tricot letter was knitted from the obtained fibers, and mold processing evaluation was carried out. The evaluation results are shown in Table 1.

[Example 3]

The spinneret was made into a spinneret having 68 holes having a discharge hole diameter of 0.20 mm and a hole length of 0.4 mm. The discharge amount of the gear pump 1 was 30.42 g / min, the first roll main speed was 3,600 m / A polyamide 56 fiber of 78 dtex 68 filaments was obtained in the same manner as in Example 1 except that the roll main speed was 3,960 m / min and the winding speed was 3,900 m / min. Table 1 shows the physical properties of the obtained fibers. Further, a tricot letter was knitted from the obtained fibers, and mold processing evaluation was carried out. The evaluation results are shown in Table 1.

[Comparative Example 1]

The discharge amount of the gear pump 1 was set at 30.9 g / min, the spinneret was set at φ0.30 and the hole length was set at 0.6 mm, and 13 holes were drilled at a first roll main speed of 1,500 m / min and a second roll main speed of 4,440 m / Min, and the winding speed was 4,050 m / min, polyamide 56 fibers of 78 dtex 13 filaments were obtained in the same manner as in Example 1. Table 1 shows the physical properties of the obtained fibers. Further, a tricot letter was knitted from the obtained fibers, and mold processing evaluation was carried out. The evaluation results are shown in Table 1.

[Comparative Example 2]

Except that the discharge amount of the gear pump 1 was 35.1 g / min, the first roll main speed was 4,400 m / min, the second roll main speed was 4,600 m / min, and the winding speed was 4,550 m / min. Polyamide 56 fibers of 78 dtex and 24 filaments were obtained in the same manner. Table 1 shows the physical properties of the obtained fibers.

[Comparative Example 3]

Except that the discharge amount of the gear pump 1 was 28.9 g / min, the first roll main speed was 2,000 m / min, the second roll main speed was 3,730 m / min, and the winding speed was 3,700 m / min. Melt spinning was carried out in the same manner, but spinning yarn breakage occurred frequently, and stable spinning could not be achieved.

[Comparative Example 4]

The melt spinning was carried out in the same manner as in Example 1 except that the spinneret had a spinneret having 24 holes of round holes with a diameter of 0.40 and a hole length of 0.8 mm.

[Comparative Example 5]

A polyamide 66 fiber was obtained in the same manner as in Example 1 except that the polyamide 66 resin prepared in Preparation Example 2 was used in place of the polyamide 56 resin. Table 1 shows the physical properties of the obtained fibers. Further, a tricot letter was knitted from the obtained fibers, and mold processing evaluation was carried out. The evaluation results are shown in Table 1.

[Comparative Example 6]

Except that a mixed resin obtained by blending 5% by weight of polyvinylpyrrolidone with the polyamide 66 resin prepared in Preparation Example 2 was used instead of the polyamide 56 resin, and melt spinning was carried out in the same manner as in Example 1, So that stable radiation could not be achieved.

[Comparative Example 7]

Except that a mixed resin obtained by blending 5 wt% of polyvinylpyrrolidone with the polyamide 6 resin prepared in Preparation Example 3 was used in place of the polyamide 56 resin and the melting temperature and the pelletizing temperature were changed to 260 ° C. Polyamide 6 fibers were obtained in the same manner. Table 1 shows the physical properties of the obtained fibers. Further, a tricot letter was knitted from the obtained fibers, and mold processing evaluation was carried out. The evaluation results are shown in Table 1.

1: Gear pump
2: spinning detention
3: Dust cooling system
4: Lubrication device
5: First fluid interflow nozzle device
6: Draw rollers
7: Stretch roller
8: Winder
&Lt; Industrial applicability >
According to the present invention, it is possible to obtain a hygroscopic synthetic fiber having high moisture absorptivity and high added value without impairing the properties of polyamide such as strength, chemical resistance and heat resistance.
Therefore, the hygroscopic synthetic fiber of the present invention is suitable for medical use, particularly in innerwear, sportswear, and the like.

Claims (7)

A hygroscopic fiber having a? MD of 3.0% or more and a birefringence of 30 x 10 &lt; ^-3 &gt; to 40 x 10 &lt; ^-3 &gt; A process for producing a polyamide 56 fiber by direct radial stretching method in which a polyamide 56 fiber discharged from a cigarette is cooled and solidified by cooling wind, ) To (2).
(1) The speed at which the wire is discharged is 14 m / min or more and 30 m / min or less
(2) The product of drawing speed and drawing magnification is 3900 m / min or more and 4500 m / min or less A fiber product comprising the hygroscopic fiber according to claim 1. A fiber product comprising the hygroscopic fiber according to claim 1, and comprising a molded part by molding. A fiber structure comprising the fiber product according to claim 3 or 4. The fibrous structure according to claim 5, wherein the fibrous structure is innerwear. delete

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