JPH03234816A - Conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain a conjugate fiber having excellent feeling, gloss and hygroscopicity like a natural fiber and having excellent opaque property and chromophoric property comprising respectively specific amounts of saponified copolymer of ethylene vinyl acetate and crystalline thermoplastic polymer in a specific range of conjugating ratio. CONSTITUTION:The objective fiber is a conjugate fiber composed of A- component and B-component in which a polymer comprising the A-component is a saponified copolymer of ethylene-vinyl acetate having 25-70mol% ethylene content and >=95% degree of saponification and the B-component is a crystalline thermoplastic polymer (preferably polyethylene terephthalate or nylon-6, etc.) containing >=1.5wt.%, preferably >=2.5wt.% inert fine particles (preferably silica, titanium oxide or barium sulfate) having <=5mu, preferably <=1mu averaged particle diameter and having >=150 deg.C melting point. A conjugating ratio of A:B is (10:90) to (90:10).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to an ethylene vinyl acetate material that has a good texture similar to natural fibers, good gloss and hygroscopicity, and has excellent opacity and color development. It relates to a saponified copolymer composite fiber, more specifically, a saponified ethylene-vinyl acetate copolymer polymer = 1 (component polymer) and crystals containing inert fine particles for imparting opacity. The present invention relates to a composite fiber characterized in that it is composited with a thermoplastic polymer (component B polymer).

(Prior art) Natural fibers, both cellulose-based and protein-based, contain water and other liquids in cell tissue.1. The solid polymer component remains by removing the foreign matter, and the fine structure of the cell tissue gives it moisture absorption performance and the good glossy texture of natural fibers, while also being opaque without a plastic feel. It is thought that it gives sex.

On the other hand, conventionally, polyester fibers are hydrophobic, so
The disadvantage is that the fiber itself is poor in water absorption and moisture absorption. Time 47-23134 is a technology for polyester fibers containing polyalkylene glycol to improve water absorption.
No. 47-11280, No. 47-43772, etc. have been proposed.

However, with these techniques, the tear strength of the resulting fabric is low, the appearance is dull, it has a unique plastic-like flat gloss, and the light fastness of the dyed product is poor and the product value is unsatisfactory. be.

In addition, as a recent trend in clothing needs, there is an increasing demand for tennis wear used in leisure sports, and white coats used in the medical field, but this is insufficient to provide desirable opacity. . There is also a method of processing fabrics to make them opaque, but this has the problem of hardening the fabrics, and also has the disadvantage that the opacity imparted by the process disappears when washed. On the other hand, there is a method of making the fiber itself opaque by adding fine particles to impart opacity to the synthetic fiber, but simply adding fine particles to the fiber-forming polymer results in a dull whitish color. However, the brightness of the colors is not satisfactory.

In addition, fiber structures such as woven, knitted, and nonwoven fabrics made of synthetic fibers, such as polyester and polyamide filaments, are compared to natural fibers such as cotton and linen because their constituent filaments have a monotonous single denier and a monotonous cross-sectional shape. The texture and luster were monotonous and cold, and the quality as a fiber structure was low.

In recent years, various attempts have been made to improve these drawbacks, such as making the fiber cross section irregular, crimping, and composite fibers.
The current situation is that the objective has not yet been fully achieved.

Moreover, synthetic fibers such as polyester have insufficient hydrophobicity, so they are inferior to cotton in terms of comfort.

(Problems to be Solved by the Invention) The present invention provides opacity to synthetic fibers, prevents poor color development (that is, a dull whitish color) that occurs when opacity is imparted, and The purpose is to give fibers a texture and moisture absorption similar to those of natural fibers, as well as a luster with a good natural feel, and for this purpose, the polymer design and manufacturing conditions that do not cause trouble in the fiberization process are developed. This has been investigated.

(Another Means to Solve the Problems) The present invention has an ethylene content of 25 to 70 mole, a degree of saponification of 9
A saponified product of 4-mer ethylene-vinyl acetate copolymer having a modulus of 5 or higher (component A) and a crystalline thermoplastic polymer having a melting point of 150°C or higher containing inert fine particles (component B)
It is a composite fiber characterized by consisting of.

First, the necessary requirements for the component A polymer will be explained in detail. The polymer must have a high degree of saponification of 95 or higher and an ethylene content of 25 to 70 moles, that is, a vinyl alcohol component of 30 to 70 moles. 75 moles is optimal. A
As the vinyl alcohol component content in the component polymer decreases, properties such as hydrophilicity naturally decrease due to a decrease in hydroxyl groups (OH) [-1, which will be described in detail later, will have the desired good hydrophilicity. This is undesirable because a texture similar to natural fibers cannot be obtained. However, if the vinyl alcohol component content increases, the melt formability decreases, and after composite spinning with component B, the spinnability may be poor when it is made into fibers, and wheel yarn breakage or breakage may occur during spinning or drawing. There will be a lot of thread, which is not desirable. Furthermore, as an example, when polyethylene terephthalate is used as component B, the heat resistance at the spinning temperature of 250 DEG C. or higher is also insufficient, which is also not appropriate. Therefore, it can be said that a fiber having a high saponification degree and a vinyl alcohol component content of 30 to 75 moles is suitable for obtaining the fiber of the present purpose.

The A-component polymer is produced by saponifying the copolymerization of ethylene and vinyl acetate using caustic soda, but the degree of saponification must be 95 or higher. When the saponification degree decreases, not only does the crystallinity of the polymer decrease and the fiber physical properties such as strength decrease, but also the A component polymer tends to soften, causing problems in the processing process and the resulting fiber. The texture of the structure is also bad, which is not desirable.

Another important requirement for obtaining the fiber of the present invention is B.
Melting point 1 containing a predetermined amount of inert fine particles as a component
A crystalline thermoplastic polymer having a temperature of 50° C. or higher is used.

The polymer for component B having a melting point of 150 DEG C. or higher in the present invention may be any polymer having a melting point of 150 DEG C. or higher and having good fiber-forming properties, such as polyester 6-ester, polyamide, polypropylene, and the like. Preferably, it is a polyester whose main constituent unit is ethylene terephthalate or butylene terephthalate, or a polyamide whose main constituent is nylon 12, nylon 6, or nylon 66.

Examples of the polyester include terephthalic acid, inphthalic acid, naphthalene 2,6-dicarboxylic acid, phthalic acid, α,β-(4-carboxyphenoxy)ethane,
, 4-dicarboxydiphenyl, aromatic dicarboxylic acids such as pentasodium sulfoiphthalic acid or adipic acid, tonoaliphatic dicarboxylic acids such as sebacic acid, or esters thereof, ethylene glycol, diethylene glycol, 1.4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane 1,4
- A fiber-forming polyester synthesized from a diol compound such as dimetazole, polyethylene glycol, or polytetramethylene glycol, in which 80 or more mole units, especially 90 or more mole units of the constituent units are ethylene terephthalate units or butylene ethylene phthalate units. Certain polyesters are preferred. The polyester may also contain small amounts of additives, fluorescent whitening agents, stabilizers, ultraviolet absorbers, and the like.

In addition, polyamides include nylon 6, nylon 66,
It may be a polyamide containing nylon 12 as a main component, or a polyamide containing a small amount of a third component. These may contain small amounts of additives, fluorescent brighteners, stabilizers, etc.

More importantly, the amount of inert fine particles in the component B polymer is 1.5 wt or more, more preferably 2 wt or more.
Qwt% or less, more preferably 2.5 wt% or more. Conventionally, incorporation of inert fine particles has been used as a method of imparting opacity to fibers, but as mentioned above, there was a problem in that the color development after dyeing was poor. However, by forming a composite fiber structure with a saponified ethylene-vinyl acetate copolymer, it was possible to obtain fibers with good color development and good opacity.

Examples of inert fine particles include alumina, zirconia,
Examples include barium sulfate, calcium carbonate, magnesium oxide, silica, titanium oxide, aluminum phosphate, calcium phosphate, zinc oxide, etc., but silica , titanium oxide, bread sulfate, more preferably 1 micron or less, and the reason for this is to improve process properties such as spinnability, stretchability, and false twistability.

It is currently unclear exactly why the cross-section of the present invention is able to have both good opacity and good color development properties, but perhaps the refractive index of the A-component polymer is higher than that of ordinary polyesters or polyamides. Due to the relatively low transparency of light when it passes through the A component polymer, the gloss and vividness of the color, which is commonly referred to as wet color development, is developed due to the inertness in the B component polymer. This is presumed to be because the reduction in color development due to fine particles is sufficiently compensated for.

The composite ratio of the A-component polymer and the B-component polymer is preferably 10 to 90% by weight of the A-component polymer. Naturally, a conjugate fiber containing the component A polymer and having a weight of 10 weight and a diameter of 1D loses properties such as hydrophilicity, which is one of the characteristics of the fiber, due to a decrease in hydroxyl groups. When the A component polymer content exceeds 90% by weight, the A component polymer, which has slightly poor spinnability, becomes rich, resulting in poor processing properties such as spinning and stretching. In addition, the A polymer becomes rich in the fiber surface layer, and the texture is often unfavorable, as the degree of single rooting between single i males becomes severe and the fiber becomes hard.

Next, examples of composite shapes of the composite fibers of the present invention will be shown.

Model diagrams of specific composite forms are shown in FIGS. 1 to 1 as representative examples. 1 and 2 are core-sheath type cross sections. FIGS. 3 and 4 are composite cross-sections of the bonded type. 5th to 7th
The figure shows a multilayered composite cross section, and depending on the selection conditions of the A-component polymer and the B-component polymer, it is possible to divide it into ultra-fine structures. Figures 8 to 11 show a type in which the fiber cross section is divided toward the center, and only the A component is divided, or only the B component is divided. FIG. 12 shows an example of a hollow cross-section fiber, which is of a type in which the A component and the B component are divided into annular shapes. FIG. 13 is an example of a type in which the A component and the B component are divided into two in the direction of the center of the fiber cross section. FIGS. 14 and 15 are examples of composite shapes of irregular cross-section fibers.

FIG. 16 is an example of a composite shape of non-uniform mixture of A component and B component. This can be obtained by appropriately dividing the A component and the B component into layers using a 4-8 element static mixer immediately before discharging them from a spinning nozzle, and then discharging them from a nozzle hole. FIG. 17 is an example of a core-sheath composite shape in which the core component is component B and the sheath component is a polymer blend component of components A and B.

In particular, in the present invention, whether the cross-sectional shape of the fiber is a core-sheath shape as shown in Figs.
Alternatively, as shown in Figure 3.8.10.14, fibers in which the majority of the fiber surface is covered with component A are extremely excellent in terms of color development. Of course, even if only a portion of the fiber surface is covered with the A component, or if the A component is not substantially present on the fiber surface, in a fabric made of such fibers as an aggregate, Improvement in color development can be obtained to some extent.

It goes without saying that the effects of the present invention can be expected from not only long fibers but also short fibers obtained by the present invention.

Furthermore, the fibers obtained by the present invention can be formed into shapes resembling pentagons or hexagons through high-order processing such as false-twisting and crimp processing, or into trilobal or hexagonal shapes through irregular cross-section nozzles during spinning. Even if the fiber is multi-lobed, such as T-shaped, four-lobed, six-lobed, eight-lobed, etc., or has various cross-sectional shapes, as long as it meets the requirements explained so far,
It is possible to obtain a fiber structure of the present invention that maintains good hand feel and good opacity.

Further, the component A polymer is a polymer with a melting point of around 150 to 180°C, and the phenomenon of melting point drop actually occurs in hot water, and it becomes easy to soften even below 150°C. Therefore, when polyester is used as the B polymer, the A component polymer easily softens under the normal dyeing conditions of polyester fiber fabrics and the setting temperature of the fabric. If the exposed surface area of the fiber is large, depending on the processing conditions, a softening phenomenon may occur, leading to a sticking phenomenon between the single fibers.

When it is desired to adjust the hardness of the texture due to the sticking phenomenon to some extent, the A component polymer is acetalized using a monoaldehyde such as formaldehyde or a dialdehyde such as glyoxal or glutaraldehyde to impart hot water resistance. A high-temperature dyeing treatment of a fabric such as polyester may be performed later. It is preferable to carry out the process as necessary.

An example of specific conditions for acetalizing the fibers of the present invention is that a strong acid such as sulfuric acid, formic acid, or hydrochloric acid is used as the acetalization reaction catalyst, and the concentration of the strong acid used is 0.
Set it to above the 05 standard and below the 2 standard. Tsuite, 0HC
-CnH2n-CHO (n=O-10) aldehyde at 0.2f'/j2 or more, 500'771. It is preferable to treat the fibers at a reaction temperature of 15° C. or higher and 135° C. or lower using a solution with the following concentration. When a dialdehyde is used as the aldehyde, acetalization with the dialdehyde may result in non-crosslinking free aldehydes in addition to crosslinking reactions, and this aldehyde may cause discoloration of the dyed material during heating. There may be cases where In order to prevent this, it is preferable to oxidize the free aldehyde with an oxidizing agent to convert it into a carboxylic acid or a carboxylate salt.

Furthermore, when polyester is used as the B component polymer, it is possible to impart a softer feel to the fabric by subjecting the fabric to alkali weight loss treatment using a caustic soda solution.

Furthermore, when performing high-temperature, high-pressure dyeing using polyester as the B-component polymer, under high-temperature hot water conditions, a portion of the A-component polymer may be dyed (if undesirable shrinkage of the fabric occurs), it may be The presence of either a salt of a strong acid or a strong base or boric acid, either alone or in combination, can prevent undesirable shrinkage during dyeing.

The main uses of the fibers obtained in the present invention include stable fibers for clothing, dry nonwoven fabrics, wet nonwoven fabrics, and the like. Of course, 100 pieces of the fibers of the present invention may be used, or some of the fibers of the present invention may be blended with other fibers to produce a nonwoven fabric or the like to obtain the effects of the fibers of the present invention. However, it goes without saying that the effects described in the present invention cannot be fully obtained unless F# of the present invention and male are mixed in a certain ratio or more. Furthermore, the fibers of the present invention have a good texture even when they are long fibers, and are suitable for woven or knitted fabrics such as outer garments.

It was found that the fiber of the present invention thus obtained had excellent opacity without reducing color development. Two methods were used to evaluate opacity. One is to produce raw cotton from the fibers of the present invention with a single yarn denier of 2 deniers and a cut length of 51, and to apply heat-fusible fibers (the sheath component is formed from a polyethylene component) to the raw cotton. 710 type 2 denier 5
1st grade) was mixed with 20 weight mango cotton, and then passed through a miniature card with a basis weight of 405'/n? After that, a web was created and then hydroentangled at a speed of 5 m/min with a water flow of 30 m/d, air-dried, and then heat-treated in an auto dryer at 150°C and 50°C. It was made into a nonwoven fabric for use. Place the obtained non-woven fabric on white paper and place it on top of the area where the red circle mark was drawn with ink. Visually check how much the red circle on the white paper is visible through the non-woven fabric from above.
Graded evaluation.

The other method has a denier of 150d36f after stretching.
A multifilament was produced using the fiber of the present invention, and the multifilament was used as warp and weft to weave into a tack. The gray density was 80 warps/inch and 75 warps/inch under the same conditions and sifted, then the gray taffeta was changed to Actenol R-
A scouring treatment was performed at 80° C. for 20 minutes with an aqueous solution of Zoo (scouring agent) IP/2, and then heat setting was performed at 180° C. using a pin tenter to obtain a woven fabric for measurement. Next, measure L using a spectrophotometer on a white board (M20 reflectance 100%) and a blackboard (plastic reflectance 15 cm), and calculate the value A of L'(black)/L'' (white). Ta.

L"B; L value when running a fabric over a black base ~;
L" value when fabric material is layered on white base Black base; black plastic board L" value = 12 White base; standard white board L"
Value=100 It has been found that when the opacity A is 80 degrees or more, good opacity, which is not found in synthetic fibers and has an appearance extremely close to that of natural fibers, can be obtained.

The present invention will be described in detail below, and the present invention will be explained more specifically. However, the present invention is not limited to the scope of the following examples. The intrinsic viscosity of the polymer was measured using an Uebelohde viscometer in a constant temperature bath at 30° C. using a mixed solvent of equal amounts of phenol and tetrachloroethane for polyester. Polyamide was measured using orthochlorophenol at 30°C. The saponified product of ethylene vinyl acetate copolymer was measured at 30°C using 85-wound hydrated phenol.

Examples 1 to 2 Using methanol as a polymerization solvent, ethylene and vinyl acetate were radically polymerized at 60 °C to create a random polymer with an ethyl-17-lene content of 44 mol, followed by silica treatment with caustic soda. After doing this to obtain a saponified ethylene-vinyl acetate copolymer with a degree of saponification of 99 degrees or higher,
After repeatedly washing the wet polymer with pure water to which a small amount of a large excess of acetic acid has been added, the washing is repeated again with a large excess of pure water to remove alkali metal ions such as Na and My. , the alkaline earth metal ion content of Ca was reduced to about 10 pT) m or less, and then water was separated from the shiborimer using a dehydrator, and further vacuum drying was carried out at 100 °C or less to obtain an intrinsic viscosity [η ]=1.05
The A component polymer was dI2/f.

The B component polymer was ethylene glycol (hereinafter abbreviated as EG) and barium sulfate (average particle size 0.58 μm).

(median diameter: 60 mm water paste) were mixed at a weight ratio of 1:1, and further mixed and crushed using a vibrating mill (Model MB-1 manufactured by Sanei Seisakusho) for 10 hours. This is mixed with terephthalic acid (hereinafter abbreviated as TA) and EG, and EG and T
A slurry was prepared so that the molar ratio of A was 1.5, and the barium sulfate content (wt%) in the polymer was 5% and 10%, respectively, and 5b2034 was added to this slurry.
00 ppm was added. This slurry was heated to an internal temperature of 240°.
The mixture was fed to the esterification tank C for 2 hours to carry out esterification, and then the temperature was raised to 270°C over 40 minutes to complete each reaction separately. Transfer and gradually reduce the pressure to below 1 am Hy for about 30 minutes.
The strands were polymerized for a period of time, extruded into water under nitrogen pressure, and cut into chips with [η]=0.65, which were used.

Component A and component B were melted and extruded separately using an extruder, and each was weighed separately using a gear pump to obtain a composite ratio of 5015.
0, composite spinning was performed with a core-sheath type cross section with component A as a sheath and component B as a core as shown in FIG. 1, and spinning was carried out at a spinning speed of 1000 m/min.

When evaluating a nonwoven fabric, the obtained spun yarn is
Stretched in a water bath at 5°C, then subjected to shrinkage treatment in water cooling at 95°C, subjected to mechanical crimping, then subjected to relaxation heat treatment at 150°C for 10 minutes, and then cut to a length of 51 am to obtain a single yarn denier of 2 denier. I made it into cotton. After that, 20% by weight of 2 denier 51 tone 2 denier 51 type (composite fiber whose sheath component is a polyethylene component and core component is a polyester component) made by Kuraray's heat-sealable fiber N-710 type is mixed and made into a fiber web through card and random Univer. The fibrous web is entangled with a high-pressure water jet of 30 kr/ctA from a nozzle, resulting in an average basis weight of 40! A fiber-entangled nonwoven fabric of P/ni'' was obtained and used as a sample for evaluation of opacity.

On the other hand, when evaluating a woven fabric, the stretching conditions were as follows: normal roller plate stretching was carried out, and spinning and stretching were carried out under conditions such that a 150 denier 36 filament was obtained after stretching. A plain weave fabric was obtained using the obtained 150 denier 36 filament multifilament as warp and weft.

The greige density is 80 warps/inch and 75 warps/inch, and after desizing this gray plain fabric with Actenol R-ioo 1y/2 at 80°C for 20 minutes, it contains 22/λ glutardialdehyde. Acetalization (hereinafter abbreviated as GA) treatment was carried out at 90° C. for 50 minutes in an aqueous solution of sulfuric acid concentration of 0 or 3N.

Next, the temperature was set at 180°C to obtain a fabric for evaluating opacity.

The process performance until obtaining the nonwoven fabric sample or the fabric sample was good and had no problems.

In addition, the evaluation results for opacity were good, indicating that transparent material is a suitable material for prevention.

Further, the obtained fabric was dyed under the following conditions, and then dried and finished and set by a conventional method.

The resulting plain woven fabric had good color development, soft feel, bulkiness, and crisp feel similar to natural cotton fiber.

Dyeing method 1 - Examples 3 to 7 Performed in the same manner as in Example 1, under the conditions shown in Table 1.
This was done by changing the weight ratio of polymer A and polymer B, and changing the cross-sectional shape. both#! Good fiber processing properties, l
... was found to have good opacity. It was found that the fabric obtained in No. 17 had good texture and color development.

Examples 8 to 12 Examples 8 to 12 were carried out in the same manner as in Example 1, except that the type and content of the inert fine particles in component B were changed. In Examples 8 and 9, Tio2 (
Example 1
Example 11 used dispersion of colloidal silica (average particle size 0.045μ), Example 11 used dispersion of calcium carbonate (average particle size 0.08μ), and Example 12 used alumina dispersion. (Average particle size 0
．． 2 μ) was used to prepare polymers with the contents shown in Table 1, and then Example 1
It was made into fibers in the same manner as above, and further evaluation was conducted.

All of them were found to have good fiberization process properties and good opacity. Furthermore, it was found that the obtained fabric had good texture and color development.

Example 13 The same polymer as in Example 1 was used as the A component polymer,
Composite spinning was carried out under the same conditions as in Example 1 except that nylon 6 with [η) of 1.01 was used as the B component polymer.

Barium sulfate was added to nylon 6 to produce pellets using a twin-screw kneading extruder. A fiber was obtained which had good root strength and good opacity.

The woven fabric was dyed under the following conditions, and a woven fabric with a good texture and good hydrophilicity was obtained.

The sample after staining was processed by a conventional method.

Example 14 The same polymer as in Example 1 was used as the A component polymer, and B
Polybutylene terephthalate with [η) of 0.85 was used as the component polymer, and fiberization was performed under the same conditions as in Example 1 except for the following. The addition of barium sulfate to the B component polymer is
After dispersing barium sulfate in 1,4-butanediol and then performing a dispersion treatment in the same manner as in Example 1,
A conventional buterene terephthalate polymer was obtained. The rest were made into fibers in the same manner as in Example 1, and further evaluation was performed. It was found that the fiberization process was good and also had good opacity. The dyed fabrics also had good color development and good texture.

Examples 15 to 16 Fiberization was carried out in the same manner as in Example 1, except that the saponified ethylene-vinyl acetate copolymer used as the component A polymer had a different amount of ethylene copolymerization. Example 15 had an ethylene content of 32 mol, and Example 16 had an ethylene content of 56 mol.
Ta. All of them were found to have good processability and good opacity. Furthermore, the dyed fabrics had good color development and good texture.

Comparative Example 1.2 Comparative Example 1 was carried out in the same manner as Example 1, except that 0.5% barium sulfate was added to the B component polymer, and Comparative Example 2 was carried out using 20.5% TlO added. . In all cases, the level of opacity was insufficient.

Comparative Example 3.4 The same polymer as in Example 1 was used, and the composite ratios of component A and component B were changed to 5/95 and 9515, respectively. In all cases, the spinnability was not very good. Furthermore, Comparative Example 4 had an insufficient level of opacity.

Comparative Example 5.6 The experiment was carried out in the same manner as in Example 1 except that the amount of ethylene copolymerized in the A component polymer was changed, and the other conditions were the same. In Comparative Example 5, the spinnability of the component A polymer was poor and the spinnability was extremely poor. Further, when spinning was continued for a long time, gelled substances of the component A polymer clogged the spinning filter, and at the same time, a large amount of gelled substances were mixed into the fibers, further deteriorating spinnability. The stretchability was also very poor, and no samples that could be evaluated were obtained.

In Comparative Example 6, 80 mol of ethylene copolymer was used as the A component polymer, and the fiberization processability was good, and the opacity was also at a good level. The characteristic color development and texture of the dyed product were at an unsatisfactory level.

Comparative Examples 7 to 8 Tests were conducted using the saponified ethylene-acetic acid 26-vinyl monoate copolymer used as the component A polymer, with different degrees of saponification. Comparative Example 7 used a saponification degree of about 90, and Comparative Example 8 used a saponification degree of about 80. In all cases, problems such as adhesion between single yarns occurred during the drawing process, and phenomena such as severe sticking during the textile processing process occurred, and samples suitable for evaluation could not be obtained.

Comparative Example 9 In Example 1, spinning and weaving were carried out by adding barium sulfate to the A-component polymer so that the content was 5.0%, without adding barium sulfate to the B-component polymer. As a result, color development was extremely poor.

(Effects of the Invention) As described above, the present invention provides a specific ethylene-vinyl acetate copolymer saponified product and a melting point 150°C containing specific inert fine particles.
By composite spinning the above crystalline thermoplastic resin within a range that satisfies the specified conditions, it has a soft and bulky feel with good color development and good hydrophilicity not seen in conventional synthetic fibers. The present invention provides a composite fiber characterized by having a texture similar to natural fibers and excellent opacity. Margin 4 below,

[Brief explanation of drawings]

1 to 17 are representative cross-sectional views of the composite fiber of the present invention.

Claims (1)

[Claims] 1) Composite fiber consisting of component A and component B, in which the polymer constituting component A is a saponified ethylene-vinyl acetate copolymer with an ethylene content of 25 to 70 mol% and a degree of saponification of 95% or more. Component B is a crystalline thermoplastic polymer with a melting point of 150° C. or higher containing 1.5 wt% or more of inert fine particles with an average particle size of 5 μ or less, and the composite ratio of A to B is 10:90 to 90:10. A composite fiber characterized by: