JPH04361615A - Fiber having moisture-absorbing and permeating property - Google Patents

Abstract

PURPOSE:To provide the subject fiber having a new sheath-core conjugate structure and improved in the deterioration of the quality thereof at a low cost by melt-spinning nylon 4 and some other thermoplastic polymer in the sheath- core structure so that the nylon 4 is exposed on the surface of the fiber. CONSTITUTION:(A) A thermoplastic polymer comprising nylon 4 and (B) some other thermoplastic polymer (preferably nylon 6 or a polyester) are melt-spun in a volume ratio of 70/30 to 1/90 into a sheath-core structure to provide the objective fiber wherein the component A is exposed on the surface of the fiber so as to occupy >=50% of the whole cross-sectional circumferential length of the fiber.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cool-feeling fiber with excellent moisture absorption and moisture permeability, and more particularly to a novel moisture absorption and moisture permeability yarn having a core-sheath structure using polyamide 4, which has excellent moisture absorption, as a sheath component.

0002

[Prior Art] General-purpose synthetic fibers such as polyamide 6 and 66, polyester, and polyacrylonitrile have low hygroscopicity and water absorption, and as a result, they are used as clothing materials because of the high discomfort (stuffiness) caused by sweating in the summer. desired.

[0003] Methods for increasing moisture absorption include changing the polymer skeleton, such as nylon 4, nylon 2T, and piperazine-based polyamides, and blending and spinning hydrophilic compounds, but each method does not improve water absorption to a sufficient degree. If added, the spinning properties are poor, the cost is high and it is not practical, and the quality of the thread (dyeability, setting property) is not sufficient for use in clothing, so it is not practical. As a post-processing method, there is also a method of grafting a hydrophilic compound onto polyamide-6 and polyester to absorb moisture. This method causes severe deterioration of fiber quality (strength, dyeability, dimensional stability) due to grafting, and there are many problems in practical application.

[0004] On the other hand, methods for improving water absorption are based on the physical structure or surface attachment of a hydrophilic agent without changing the chemical structure of the polymer skeleton. As for the physical structure, there are methods to create fine pores inside the polymer or to change the cross-sectional shape of the fibers to create fine lines on the fiber surface to allow water to migrate through capillary action. However, this method has problems in that the quality of the fibers (strength, elongation) is insufficient and the dyeing lacks sharpness and transparency due to diffuse reflection of light. Furthermore, there is a method of attaching a hydrophilic substance to the fiber surface, but this method often has the disadvantage that the durability of the attachment is poor.

[0005]

[Problems to be Solved by the Invention] Although many methods have been devised for making these general-purpose synthetic fibers hygroscopic and water-absorbing, they have not yet been able to satisfy all aspects of spinnability, cost, and performance. An object of the present invention is to provide an inexpensive moisture-absorbing/water-permeable yarn that can improve the deterioration in yarn spinnability (deterioration of yarn quality) that always occurs in methods of increasing moisture-absorbing properties.

[0006]

[Means for Solving the Problems] The present inventors have developed a method using conventional technology, which has high hygroscopicity and has a chemical structure similar to that of nylon 6, which is currently widely used, and which has a similar chemical structure to that of nylon 6, which is highly hygroscopic and has a chemical structure similar to that of nylon 6, which is currently widely used. This invention was completed by focusing on nylon 4, which is the most practical among the various moisture-absorbing and water-absorbing polymers listed in the above section.

That is, the present invention provides a fiber made by bonding two or more thermoplastic polymers, in which at least one component is nylon 4, at least a portion of which is exposed on the surface of the fiber, and the other component is nylon 4. This is a fiber containing a thermoplastic polymer other than No. 4.

As the nylon 4 used in the present invention, a polymer obtained by polymerizing 2-pyrrolidone using a known method can be used. In order to perform spinning stably, it is necessary to use 2-pyrrolidone and CO2 rather than a polymer obtained using an N-acyl type polymerization initiator such as N-acetyl-2-pyrrolidone.
Polymers using adducts of as initiators are more suitable because they have higher molecular weights, narrower molecular weight distributions, and superior heat resistance.

As for the molecular weight of nylon 4, a polymer having an intrinsic viscosity of 1 to 8 as measured with a 0.5% by weight hexafluoroisopropanol solution is used. This value is not limited to this value as long as it has a molecular weight that is compatible with the polymer other than nylon 4 to be joined. As long as spinnability does not deteriorate due to yarn bending on the spindle surface, etc., it can be appropriately selected and used depending on the viscosity of the polymers to be joined.

[0010] As the thermoplastic polymer other than nylon 4 used in the present invention, any material having spinnability can be used, but polyesters such as polyamides such as nylon 6 and nylon 66 and polyethylene terephthalate are particularly suitable. In particular, nylon 6 and nylon 66 are more advantageous than polyester because of their higher hygroscopicity.

Examples of polyamides include nylon 6, nylon 66, nylon 6-10, nylon 6-12, nylon 11, nylon 12, polyhexamethylene isophthalamide (nylon 6T), polymethaxylylene adipamide (MDX-6), Polymethaxylylene sebacamide (MD
X-10), and copolyamides thereof, such as copolymers of nylon 6 and nylon 66, copolymers of nylon 66 and nylon 6-10, ternary copolymers of nylon 6, nylon 66, and nylon 6-10, Copolymer of nylon 6 and polyhexamethylene isophthalamide, copolymer of nylon 6 and polymethaxylylene adipamide, nylon 6
A copolymer of and polymethaxylylene sebacamide is used.

[0012] In the present invention, the melted nylon 4 and thermoplastic polymers other than nylon 4 are each melted and weighed separately, and are simultaneously discharged from the same spinning hole of a well-known composite spinneret, cooled, and then wound up.

[0013] The bonding form of nylon 4 and thermoplastic polymers other than nylon 4 can be either core-sheath type or side-by-side type, as long as a part of nylon 4 is exposed on the fiber surface, and is a sandwich in which one component is sandwiched between other components. It may be of any shape, and both components may be arranged symmetrically or asymmetrically. For example, if it has a core-sheath type structure, it may be concentric or eccentric.

The bonding ratio (volume ratio) of nylon 4/thermoplastic elastomer other than nylon 4 is preferably 70/30 to 1/90. When nylon 4 is 70% by volume or more, the amount of moisture absorbed by the yarn increases proportionally with the increase in nylon 4, but the amount of moisture that moves and radiates through the fabric knitted using the yarn is almost negligible at 70% by volume or more. Moreover, using more than 70% by volume will increase the cost of the yarn and is not necessary. On the other hand, if nylon 4 is less than 1% by volume, it is not possible to form a uniform thin film using current spinning technology, and even if a thin film with discontinuous tears is obtained, it is difficult to produce it stably over a long period of time. Further, at 1% by volume or less, the amount of moisture absorbed and the amount of moisture released are substantially the same as other thermoplastic polymers other than nylon 4, and there is no merit in compositing nylon 4.

Even when nylon 4 and a thermoplastic polymer other than nylon 4 are bonded together, nylon 4 must be exposed on the surface of the thread. If nylon 4 is completely covered with a low hygroscopic thermoplastic polymer other than nylon 4, the amount of moisture absorption can be obtained additively depending on the amount of nylon 4 bonded, but the comfort when wearing the fabric will decrease.・There is no movement or dissipation of moisture, which determines discomfort, so it is impractical. On the other hand, when nylon 4 is exposed on the fiber surface, moisture transfers through the exposed polymer layer of nylon 4, and when worn as a fabric, moisture transfers smoothly from the side in contact with the skin to the outside air side. It has the effect of reducing the amount of moisture between the skin and reducing discomfort.

Furthermore, when a thin film of nylon 4 was formed on the surface of the yarn, the amount of moisture absorbed by the yarn increased proportionally depending on the bonding ratio of nylon 4, but the amount of moisture released through the fabric was different from the amount of moisture absorbed. It exhibited a specific behavior, and as the volume ratio of nylon 4 increased, it showed a value larger than the value calculated proportionally from the moisture release amount of nylon 4 alone and the moisture release amount of thermoplastic polymers other than nylon 4 alone. When the actual fabric comes into contact with the skin, it is not necessarily the case that the moisture absorption amount of the yarn is greater for moisture release through the fabric, but rather the larger the moisture absorption amount of the yarn is, the more moisture can pass through from the skin side to the outside air side in the water-absorbing polymer layer. This is considered to be a larger value because water is more efficiently dissipated into the outside air through the water-absorbing polymer layer.

[0017]

[Examples] A more detailed explanation will be given below using examples. The nylon 4 polymer used in the Examples was prepared by the method described below, and the "moisture absorption", "moisture permeability", and "spunability" were measured by the methods described below.

Preparation of nylon 4 polymer: 30 g of 85% KOH was added to 6250 g of 2-pyrrolidone, and 1250 g of 2-pyrrolidone was distilled out in order to distill off the water produced by the reaction of 2-pyrrolidone and KOH and make the reaction system anhydrous. let Then add CO2 to 20% by volume in anhydrous N2.
Add a gas mixture of CO2 to give a concentration of 0.05 mol. After polymerization at 50° C. for 20 hours, the mixture was pulverized using a pulverizer, washed with water, and dried. Then, it was made into pellets using a melt extruder and subjected to spinning. The obtained pellets had an intrinsic viscosity of 1.5 (0.5% hexafluoroisopropanol solution).

Moisture absorption rate 10 g of drawn yarn obtained by bonding nylon 4 and a thermoplastic polymer other than nylon 4 was taken and dried in a vacuum dryer to a constant weight (
Ag). The yarn that has reached a constant weight is heated to 25℃
The sample was left standing in a constant temperature and humidity chamber at 45% RH and 25°C x 85% RH until it reached a constant weight (Bg), and the increase in weight was taken as the moisture absorption rate. Moisture absorption rate (%) = (B-A)/A x 100

Moisture permeability Ro paper (No. 5 manufactured by Toyo Ro Paper Co., Ltd.) impregnated with 100% water by weight was placed on a 10 cm x 10 cm hot plate whose surface temperature was controlled to 36°C. , on top of the measurement cloth (warp 70
d/18f drawn yarn, number of threads 105/inch, weft 7
After 15 minutes, measure the weight (Cg) of the rolled paper and calculate the amount of decrease from the weight (Dg) of the rolled paper immediately after starting the measurement. The moisture permeability rate was calculated using the following formula as the amount of moisture permeation. Moisture permeability (%)=(D-C)/D×100

Spinnable nylon 4 and thermoplastic elastomer other than nylon 4 are spun into 210d/18f or 24
Spun 0d/24f undrawn yarn at a spinning speed of 600 m/min, 8 minutes per spindle, and calculate the number of yarn breaks per spindle on the first day of spinning and after 7 consecutive days of spinning. It was used as a measure of gender.

Electron micrograph (2000x) of the sheath-forming yarn surface shows the uniform coverage of the sheath,
The state of damage was observed and evaluated.

Example 1 Concentric composite yarns with different core/sheath joining ratios were spun using the above-prepared nylon 4 as a sheath and nylon 6 (relative viscosity 2.80 in 98% sulfuric acid) as a core component. The formability, hygroscopicity of the spun yarn, moisture release amount, and spinnability were compared. That is, after separately melting prepared nylon 4 and nylon 6, the core/sheath ratio is 0.
/100,0.5/99.5,1/99,5/95,1
0/90, 30/70, 50/50, 70/30, 90
/10,100/0, 500 undrawn single yarns of 12 denier (18 filaments) were joined concentrically so that
It was rolled up at m/min. The undrawn yarn that was rolled up was heated to 27°C x 65°C.
After aging for 24 hours at %RH between two rollers (
The first roller of the two rollers is a heating roller (7
Each yarn of 70 d/18 f was obtained by drawing at a drawing speed of 600 m/min and a drawing ratio of 3.1.

Table 1 shows the hygroscopicity, moisture release rate, yarn breakage rate during spinning, and sheath formation property of each drawn yarn obtained, and the relationship between the sheath/core bonding ratio, moisture absorption rate, and moisture permeability rate is shown in Table 1. Shown in 1.

[0025]

[Table 1]

As is clear from FIG. 1, once the moisture absorption rates of the sheath nylon 4 and the sheath nylon 6 alone are determined, additive properties are established depending on the bonding ratio of each, and each sheath/core/weight ratio The moisture absorption rate is plotted on a straight line connecting the moisture absorption rates of the sheath nylon 4 and the core nylon 6 alone. On the other hand, the moisture permeability is plotted above the straight line connecting the moisture permeability of the nylon sheath 4 and the nylon core 6 alone, since additive properties do not hold. When moisture moves through the hygroscopic nylon 4 formed on the yarn surface and is released, it is better to release moisture through a short path through the yarn surface than through a long path through the center of the yarn. This shows that it has good moisture release properties. In particular, when the weight ratio of nylon 4 is 72% or more, the moisture permeability hardly increases even if the weight ratio of nylon 4 increases. Considering that the actual comfort and discomfort of wearing clothes is determined by how well moisture permeates rather than the moisture absorption rate, a sheath nylon 4 ratio of 72% or more will only lead to higher costs for the yarn. It is unnecessary for the purpose of the fiber to provide a cooling sensation, and it can be seen that a sheath nylon ratio of 70% is sufficient.

Nylon 4 has poor heat resistance stability compared to nylon 6, and when spinning for a long time, it deteriorates in the polymer retention area of the spinning channel system, reducing operability. However, in a composite yarn using nylon 6 in the core, nylon 6 has good heat resistance, and up to a weight ratio of nylon 4 of 70%, there is little spun yarn breakage and there is no problem in spinning operability. If the film thickness of the sheath part is thin, it cannot be made uniformly using current spinning technology (spinning technology), and the sheath/core joining ratio is limited to 1/99, and if the film thickness is less than that, tearing occurs.

Example 2 A monomer was produced under the same conditions as in Example 1, except that the core component nylon 6 was changed to polyethylene terephthalate (relative viscosity 1.67 in a phenol/tetrachloroethane = 6/4 vol ratio solution). A 10 denier (24 filament) undrawn yarn was wound at 500 m/min. After the rolled-up undrawn yarn was aged at 27°C x 65% RH for 24 hours,
Stretching speed is 600 m/min between two rollers (the first of the two rollers is a heating roller at 85°C, and a 30cm long plate heater with a surface temperature of 150°C is installed between the two rollers). The yarn was drawn at a draw ratio of 3.4 to obtain a drawn yarn of 75 d/24 f. Table 2 shows the hygroscopicity, moisture permeability, yarn breakage rate during spinning, and sheath formation properties of each of the obtained drawn yarns.

[0029]

[Table 2]

When polyethylene terephthalate is used for the core, the behavior of moisture absorption and moisture permeability is similar to that of nylon 6 shown in Example 1. The relationship between the sheath/core bonding ratio and the moisture absorption rate is based on the moisture absorption rate of nylon 4 and polyethylene terephthalate alone.The moisture absorption rate of each sheath/core ratio is additive, and the moisture absorption rate is proportional to the weight ratio of each sheath/core. It shows. On the other hand, there is no such tendency for moisture permeability, and when the sheath/core weight ratio is small, the sheath/core weight ratio is small.
The moisture permeability is greater than the value proportional to the core weight ratio. Further, when the sheath/core ratio is 75/25 or more, the moisture permeability tends to hardly increase, as in the case of the core nylon 6 of Example 1. Even if the spun yarn breaks, the nylon 4 in the sheath is 25.
If the amount exceeds 0.5% by weight, the increase will occur, causing an unfavorable operational situation.On the other hand, from the viewpoint of sheath component formation, the sheath will increase if the amount exceeds 0.5% by weight.
With the above method, a uniform thin film cannot be obtained and manufacturing is impossible. Therefore, even when polyethylene terephthalate is used for the core, the sheath/core weight ratio is preferably in the range of 1/90 to 70/30 in terms of moisture permeability, spinning operability, and sheath formation.

[0031]

Effects of the Invention As explained in the examples above, the yarn of the present invention has excellent moisture permeability, and the hygroscopic nylon 4 disposed in at least a part of the outermost layer of the yarn has good moisture permeability even in a thin film state. As shown, the composite structure has the effect of reducing moisture permeability even if the ratio of nylon 4 used is reduced.

[0032]

[Brief explanation of drawings]

FIG. 1 shows the relationship between the sheath/core weight ratio and the moisture absorption rate and moisture permeability of the composite yarn in a core-sheath concentric composite yarn in which nylon 4 is placed in the sheath portion and nylon 6 is placed in the core portion.

FIG. 2 shows various shapes in which nylon 4 is exposed and bonded to at least a portion of the fiber surface.

Claims (4)

[Claims] Claim 1: A fiber made by bonding two or more thermoplastic polymers, in which at least one component is nylon 4.
A fiber having a bonded shape in which at least a portion thereof is exposed on the fiber surface, and the other component is a thermoplastic polymer other than nylon 4. Claim 2: The bonding ratio (volume ratio) of nylon 4/thermoplastic polymer other than nylon 4 is 70/30 to 1/90.
The fiber according to claim 1. 3. The fiber according to claim 1, wherein the circumferential length of the nylon 4 exposed on the fiber surface in the yarn cross-sectional area accounts for 50% or more of the total circumferential length. 4. The fiber according to claim 1, wherein the thermoplastic polymer other than nylon 4 is nylon 6, nylon 66 or polyester.