JPH0369611A - Special conjugate fiber and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having hydrophilic property and excellent softness and bulkiness by individually subjecting saponified specific ethylene-vinyl acetate copolymer and crystalline thermoplastic polymer to melt extrusion, making to laminar conjugate shape and spinning with dividing and distributing in specific condition. CONSTITUTION:(A) Saponified ethylene-vinyl acetate copolymer of 30-70mol% ethylene content and >=95% degree of saponification and (B) crystalline thermoplastic polymer having fiber-forming property and >=150 deg.C melting point respectively having >=400 poise melt viscosity at 290 deg.C and at zero-shearing stress and melt viscosities etaA and etaB satisfying formula I are individually subjected to melt extrusion and made to laminar conjugate flow with a weight ratio of A:B=10:90-90:10 within 5min after contact of the both, then resultant flow is radially re-divided and redistributed to a dividing numbers less than the number of nozzle holes, thus spun from multi-hole spinning nozzle to afford the aimed fiber having randomly different conjugated shape between each single fiber in spite of same shape in longitudinal direction and having average value x of contact length of the both to average peripheral length y in fiber cross section satisfying formula II or formula III (a and b are wt.% of the components A and B).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is soft, has excellent bulkiness, and has hydrophilicity.
This article relates to synthetic fibers that have a good texture not seen in conventional synthetic fibers, and a method for producing the same. More specifically, the ethylene content is 30 to 70 mol%, and the composite shape of two types of polymers, a saponified product (hereinafter sometimes abbreviated as EVAL) and a crystalline polymer, is substantially the same in the length direction of the fiber. However, the single fibers differ randomly, and the single fibers have a composite shape in which one component forms a layered divided layer, and a composite shape in which one component forms an independent island component. A new composite filament with natural irregularities and soft texture resembling natural fibers, which is a mixture of composite filaments and composite filaments that form a kind of bonded structure in which two components are unevenly distributed. The present invention relates to a composite staple and a method for manufacturing the same.

(Prior Art) Conventionally, fiber structures such as woven fabrics, knitted fabrics, and non-woven fabrics made of filaments of synthetic fibers, such as polyester and polyamide, have a monotonous single filament denier and a monotonous cross-sectional shape. Compared to natural fibers, the texture and luster are monotonous and cold, and the quality of the fiber structure is 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.
However, the current situation is that the purpose has not been fully achieved. For example, JP-A-56-165015, JP-A-57-
No. 5921, JP-A-58-98425, JP-A-61-
No. 239010, etc., a composite fiber of easily soluble polymer and polyester is formed, and then post-processing gives the woven or knitted fabric a dry-touch texture and unique luster. Special Public Service 51-72
No. 07, JP-A-58-70711, JP-A-62-13
As shown in No. 3118, etc., a method of improving the texture by imparting unevenness in the length direction of the fibers, Meri is a method of improving the texture of the fibers.
As shown in Japanese Patent Publication No. 3-35633 and Japanese Patent Publication No. 56-16231, methods of fibrillating synthetic fibers to improve the texture, and methods of improving the texture of synthetic fibers, such as false twisting and fusion, as proposed in Japanese Patent Publication No. 45-18072. A method of creating a bound yarn and giving it a crisp feel using a loosening machine, or a method of creating a mixed fiber fused yarn as in JP-A No. 63-6123, or a method of creating a mixed fiber fused yarn as in JP-A No. 63-6123.
Various methods have been proposed, such as a fibrillation method as in No. 3-6161. However, it has not been sufficient to impart a texture similar to that of natural fibers to synthetic fibers, and in particular, it has been insufficient to impart a texture similar to natural hemp fibers or natural cotton fibers. In addition, synthetic fibers such as polyester have insufficient hydrophilic properties, so they are inferior to cotton in terms of comfort.

(Problems to be Solved by the Invention) The present invention imparts hydrophilicity to conventional synthetic fibers by compounding them with a polymer having water tR groups (OH groups),
Furthermore, as a result of intensive studies aimed at imparting a soft texture similar to natural fibers such as cotton or silk, as well as natural unevenness between single fibers, the present invention was achieved. .

That is, the present invention has investigated what kind of material should be used and what kind of configuration and conditions should be used in order to obtain the above-mentioned fiber. , degree of saponification 9
Saponified product (A
11i11) and a crystalline thermoplastic polymer with a melting point of 150°C or higher (component B),
A composite shape in which the component and BfFC component is substantially the same in the length direction of the fiber but differs randomly between single fibers, and one component forms a layered divided layer; The fibers are randomly formed with a mixture of fibers with a composite shape in which the components form independent island-like components and fibers with a composite shape resembling a bonded structure in which the two components are unevenly distributed. Moreover, it is a special composite fiber characterized in that the contact length at the interface between component A and component B satisfies a certain condition.

Polyvinyl alcohol (hereinafter abbreviated as PVA) R fibers produced from saponified vinyl acetate polymers are not satisfactory in terms of morphological stability and durability in a water-containing state. This is an essential drawback of hydrophilic fibers like cotton and rayon. Hydrophobic m-fibers such as polyester and polyester are excellent in this respect, but their quality is inferior to hydrophilic fibers in terms of hydrophilicity and plastic feel.

As is well known, in an attempt to provide an ideal fiber that complements the length and shortness of the above-mentioned conventional fibers, our predecessors have used methods such as polymer modification and copolymerization, but these methods alone cannot satisfy both characteristics. I haven't gotten anything. Furthermore, in order to obtain a composite form, hydrophobic fibers must be melt-spun, and hydrophilic fibers must be spun by wet or dry spinning, and therefore composite spinning of both is considered difficult according to common knowledge in the art.

The present inventors solved these problems and established a method for producing synthetic fibers that are soft, have an excellent bulky feel, are hydrophilic, and have no plastic texture.

Saponified ethylene vinyl acetate copolymer as component A (
The most suitable material (EVAL) is one with a high saponification degree of 95 or more and an ethylene content of 30 to 70 moles, that is, a vinyl alcohol component of 30 to 70 moles. If the vinyl alcohol component content in EVAL is lower, properties such as hydrophilicity will naturally decrease due to the decrease in hydroxyl groups (OH), and as will be discussed in detail later, it will not be possible to achieve the desired natural fiber-like appearance. It is no longer possible to obtain a good match, and m1 is not good. ! If the content of the vinyl alcohol component is too high, the meltability will decrease, and after composite spinning with component B, the stringiness will be poor and there will be many single yarn breakages and yarn breaks. , B is an example of an unfavorable case.
When polyester is used as a component, the spinning temperature is 25
It is also unsuitable because its heat resistance at temperatures above 0°C is insufficient. Therefore, it can be said that EVAL with a high saponification degree and a vinyl alcohol component content of 30 to 70 mol φ is suitable for obtaining the fiber of the present purpose. Polymer A is produced by saponifying the copolymerization of ethylene and vinyl acetate using caustic soap, and the degree of saponification at this time is preferably 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 polymer tends to soften, causing problems in the processing process and the resulting fiber structure. The texture of the object also deteriorates, which is not desirable.

In the present invention, the B polymer having a melting point of 150°C or higher includes:
Any polymer having a melting point of 150° C. or higher and good fiber-forming properties may be used. Preferably, m1 is polyester containing polyethylene terephthalate or polybutylene terephthalate as a main component, or polyamide containing nylon 6 or nylon 66 as a main component.

Examples of the polyester include terephthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, phthalic acid, α,β-(4-carboxyphenoxy)ethane,
．． Aromatic dicarboxylic acids such as 4-dicarboxydiphenyl, pentasodium sulfoisophthalic acid or aliphatic dicarboxylic acids such as adipic acid, sebacic acid, or their esters, ethylene glycol, diethylene glycol, 1゜4-butanediol, neo It is a fiber-forming polyester formed from a diol compound such as pentyl glycol, cyclohexane 1,4-dimethanol, polyethylene glycol, polytetramethylene glycol, etc., and the constituent units have 80 moles or more, especially 90 moles or more. A polyester having polyethylene terephthalate units or polybutylene terephthalate units is 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 is a polyamide containing nylon 12 as a main component, and may also be a polyamide containing a small amount of a third component. These may contain small amounts of additives, fluorescent brighteners, stabilizers, etc.

Next, the characteristics of the fiber of the present invention will be explained with reference to actual photographs. FIG. 1 shows an example of a cross-sectional photograph of the fiber of the present invention.

FIG. 2 shows a model diagram of a typical cross-sectional shape as an example.

The one shown in Figure 1 has an ethylene component of 4 as the A component.
It was spun at a weight ratio of 30:70 using polyethylene terephthalate as the B component and EVAL having a saponification degree of 4 mole and a saponification degree of 99. The composite shape of the A component and the B component varies randomly between single fibers, and the A component may form a layered divided layer, or an independent island-like component; As shown in Figure (a), there are cases where the A and B components are extremely unevenly distributed, forming a composite shape resembling a bonded structure, and it is possible that a multifilament is formed in a state where they are mixed. Recognize. Because these various composite shapes are mixed, some of them cause a shrinkage strain difference due to the strain difference between the A component and the B component. When made into a product, a non-clustered coil crimp with a phase different from that of other single fibers appears, resulting in bulkiness, and in the case of Figure 2 (b), some separation occurs at the interface between component A and component B. In the final fiber product, fibrillar ultrafine fibers are randomly generated in the form of branches from the single fiber surface layer, and this is the point that gives the product a soft feel when it comes into contact with the product. In addition, in the case of the fiber forming the shape shown in Figure 2 (c), one of the components has several rather large island-like independent layers, so the fiber cannot be obtained as a complete core-sheath fiber. Brings natural softness. In this way, the composite shapes between single fibers vary randomly, and the shapes are mixed, as represented by the model shapes shown in Figure 2 (a), (b), and (c). For the first time, it has become possible to express the natural mottling and texture similar to fibers, especially the bulkiness and softness to the touch, as well as the overall softness of the fiber aggregate. The method for obtaining fibers with such a composite shape will be explained in detail later, but by creating a fiber aggregate with the composite shape described above, it is possible to create a texture resembling that of natural fibers for the first time. It became possible to express it.

Another major feature is that the average contact length X at the interface between component A and component B applied to the fiber cross section is expressed by the relationship shown in the following equation with respect to the average circumference y of the fiber cross section.

A major feature is that a mixture of fibers exists in a composite state in which the boundary between the average circumference y of the single fiber cross section, the Aff component, and the B component is distributed over a wide range. For example, when the weight ratio of the A component and the B component is 1:1, to explain it in terms of a model, in the bonded cross section as shown in FIG. 6(d), x/y is 0.3 to 0.4. It is about A as shown in Figure 6 (E).
In the cross section where the component, Be, and the component form 5 layers, x/y is 1.08 to 1.10 (rather, and the larger A component and B component in Figure 6 (f) form 10 layers. x/
y is about 1.8 to 2.1. On the other hand, some of the fibers of the present invention have a small X value of 0.50,
There are some with a large x/y of about 4.0, and the contact interface between the two components ranges from small to large 1, and fibers with various composite shapes are mixed in a very wide range. I understand. A major feature is that x/y is distributed over a wide range from small to large cases, and is a major factor why the fibers of the present invention exhibit natural unevenness and a feel similar to natural fibers. 0 The contact length of the A component and B component applied to the fiber cross section was measured by randomly sampling 100 single fibers and A,! : The contact length of B was measured and expressed as the average value. The specific contact length can be measured accurately by image analysis using a computer, but it is convenient to enlarge the fiber cross-sectional photograph to a high magnification, place a grid on it, and draw the two-component boundary line. It is possible to do this by reading the number of rows in the 2-component boundary line, or by rotating and scanning the two traveling gears on the curve of the two-component boundary line using a map measure. The numerical values in the examples described in the present invention are explained using numerical values measured using a map measure.

Next, an example of manufacturing the fiber of the present invention will be described.

In order to develop the composite shaped fiber structure of the present invention, two polymer components, polymer A and polymer B, are mixed heterogeneously under certain conditions during spinning, and an average-mixed polymer flow is applied to each nozzle hole under different conditions. Distribution is important, and an example of the spinning method is shown in FIGS. 3 and 4. Third
The process can be completed by spinning using a composite spinneret device as shown in Fig. 4. The polymer melt streams of A polymer and B polymer each extruded by separate melt extrusion modes are:
After each predetermined meal is weighed separately using a weighing machine, it is filtered in the filtration section 8 of the sandbox 1, and then passed through the filters 6. After being mixed at the bottom and distributed radially through the distribution channel 7 of the distribution plate 3, the polymer flows into the circumferential groove 9 and is then spun out from the die plate 10.

Here, it is very important to appropriately select the number of mixing elements in the static mixer 5 in order to achieve a non-uniform mixing state of the two polymers. There are several types of static mixers currently in use, but for example, a static mixer made by Kenics that divides the mixer into 2n layers when passed through n elements with 1800 left and right twisted blades arranged at a 900 degree offset is used. If the number of elements is 3 to 1
It needs to be in the range of 8. Furthermore, m1 is optimally in the range of 4 to 6. When the number of polymers is 8 or more, the miscibility of polymer A and polymer B becomes too good and the mixture becomes close to uniform, making it difficult to form fibers and develop the desired fiber structure.

Also, if the number of elements becomes too large, if polyester or polyamide is used as the EVAL%B polymer for AyN remer, the polyester or polyamide and EVAL will be mixed too uniformly, resulting in ester bonds in polyester and amide bonds in polyamide forming during melt mixing. A chemical reaction between EVAL polymer's hydroxyl groups partially progresses, and EV
It was found that gelled products of three-dimensional crosslinking caused by the reaction of AL were rapidly generated, and spinning became impossible. In order to prevent the formation of gelled products, polyester or polyamide and EVAL are mixed immediately before spinning, and mixing them unevenly in a single period of time and extruding them from the spinning nozzle reduces the possibility of a gelation reaction between the two component polymers. It turned out to be a very effective method from this point of view.

Even if an appropriate number of elements is set, if the residence time at 1, which is discharged from the nozzle hole, is too long after the two component polymers start contacting, the EVAL and polyester or polyamide
The reaction tends to proceed easily, and the viscosity decreases during spinning, and the coloring of the fibers progresses, which is undesirable. It is preferable to discharge within 5 minutes, more preferably within ml or 3 minutes after both component polymers start contacting. In order to reduce the residence time, the polymer channels in the distribution plate 3 need to be adequately spaced.

Another important thing to obtain the fiber of the present invention is: The structure of the distribution plate 3 is very important. Figure 4 is a detailed drawing of the distribution plate seen from the plane shown in Figure 3X-.What is important about this distribution plate is that the two-component polymer flows out in a multilayered state through a static mixer, resulting in non-uniform mixing. This method divides the flow by the number of radial distribution channels to divide the heterogeneous mixed flow radially.

The number of distribution channels needs to be smaller than the number of nozzle holes. Preferably, the ratio between the number of distribution channels and the number of nozzle holes should be in the range of 1:1.5 to 1:5. The example shown in FIG. 4 is an example in which 12 distribution paths are set for a 24-hole nozzle.

To explain in more detail using a model the flow of two-component polymers in a non-uniformly mixed state when they are discharged from a static mixer through a distribution channel through a nozzle hole, for example, the flow of two-component polymers after passing through a four-element static mixer. As shown in FIG. 5, a laminar polymer flow with 8 layers for the A component and 8 layers for the B component results in a total of 16 layers. When the polymer flow is passed through a distribution plate having 12 distribution channels, such as the fourth factor, each distribution To the road (1) - (
(12) is distributed in the state of polymer flow, (1), (12)
), (6), (7) blocks have an extremely small number of layers, and (
3), (4), (10), and (9) are in the state with the largest number of layers, and (2), (5), (8), and (11) are in the middle state in the nozzle upper circumferential groove. reach.

After that, when two or more nozzle holes are arranged in the bath block, the polymer flow from both blocks flows into the nozzle holes existing at the boundary of the block, (1), (12)
, (6), (7) and (3), (4), (9), (10)
Because the difference in the mixing state between the
As a result, the fibers shown in FIG. 2 (a), (b), and (c) are obtained in which complex shapes of complex shapes are mixed among the single fibers.

(1), (6)% (7), (12) blocks mainly develop fibers with a composite shape similar to (a) or (o) K (3)% (4), (9 )% (1
Fibers with a composite shape mainly centered on ()9 are developed from the 0) block, and (2), (5), (8), (10
) Fibers are obtained from the block, with fibers mainly having a composite shape mainly centered on (B) and fibers having a composite shape similar to (A) or (C) mixed together to some extent.

However, since the polymer stream flows steadily in the same mixing state in the time direction, the fibers maintain substantially the same composite shape in the longitudinal direction of the fibers.

2n even when using a static mixer manufactured by Kenix Co., Ltd.
There is no need to say that it is necessary to use a mixer set to a number of elements that resonate more than layer division. For Hi-Mixer manufactured by Toshisha and Ross ISG mixer manufactured by Charles & Roas, the number of layer divisions when passing through n elements is 4n layers, so the number of elements is 2. It is preferable to set the number of elements to 4 or more elements.

The composite ratio of A polymer and B polymer is 10:90-90
It is necessary to keep it in the range of 1O. If either component is less than 15 times i4, the aggregation state of the component with a low ratio becomes small, and even if the desired composite shape is obtained, the fiber will not exhibit the housing characteristics, which is undesirable. It is desirable that the optimum mixing ratio be selected within the range of A:B from 10:90 to 90:10, based on a comprehensive judgment based on the desired texture, processability, yarn properties, etc.

Furthermore, in order to form the desired composite shape, it is necessary to use a polymer with a melt viscosity within an appropriate range. That is, each of Polymer A and Polymer B has a melt viscosity of 400 poise or more under zero shear stress at 290°C, and the relationship between the melt viscosity η of Polymer A and the melt viscosity η8 of Polymer B is expressed by the following formula (8). need to be met.

ηB≦20×ηA・・・・・・・・・(3) η9; 1st
Melt viscosity of component (A) under zero shear stress at 290°C η8; Melt viscosity of second component (B) under zero shear stress at 290°C Melt viscosity under zero shear stress described here η( The measurement of BOYS) was carried out using a Toyo Seiki ■ cavilograph. Calculate the shear stress when changing the shear rate for the polymer in a cell heated to 290°C, calculate the apparent melt viscosity, and calculate the value under zero shear stress from the relationship between the shear rate and the apparent melt viscosity. The melt viscosity was extrapolated. There are various methods for extrapolating the melt viscosity under zero shear stress, but here we use the reciprocal (1) of the apparent melt viscosity (ηa).
Plot the relationship between /η8) and the sliding speed (~) on a graph, and from the obtained linear relationship, calculate the 1/η8 value at 7W → 0 and 1
/η and calculated the value of η under zero shear stress. In addition, for ease of measurement, a pellet-like polymer was used as the measurement sample, so the melt viscosity at the time of actual spinning during fiberization was determined by measuring [η] of the fiber after fiberization. Judgment was made with reference to η measurement data using four-dimensional [η] polymer pellets.

If the η of the A polymer is less than 400 voids, the spinnability will be extremely reduced, which is not preferable. This is believed to be based on the basic polymer material due to the stringiness of the A polymer. It is necessary to set the degree of polymerization of the A polymer so that η9 at 290° C. is 400 voids or more. It is preferable that the degree of polymerization is about 200 or more in number average molecular weight.

In addition, it is necessary that η3 of polymer B is 20 times or less than η.If η8 exceeds 20 times, η during composite spinning
Otherwise, the difference in melt viscosity in η8 becomes too large and the balance tends to be lost, which is undesirable because single yarn breakage and yarn breakage due to diagonal orientation, screws, etc. during spinning increase. It has been found that spinnability is improved by setting η8 to 20 times or less of η9. It goes without saying that it is necessary to set the degree of polymerization of the A polymer to an appropriate value so as to satisfy the above conditions.

In addition, EVAL made with A polymer has a melting point of 150 to 1
It is a polymer whose temperature is around 70°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 EVAL polymer is easily softened by the temperature at which the polyester fiber fabric is set, so that a certain level of EVAL in a non-uniform state may occur in the polyvarnish, such as the fibers of the present invention.
When a polymer aggregate is formed, a softening phenomenon occurs, leading to a sticking phenomenon between single fibers. If you want to adjust the hardness of the texture due to the sticking phenomenon,
The acetalization reaction of EVAL may be carried out using a monoaldehyde such as formaldehyde or a dialdehyde such as glyoxal or glutaraldehyde to impart hot water resistance, and then high-temperature dyeing treatment of a fabric such as polyester may be carried out. It is preferable to carry out the process as necessary.

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

It goes without saying that the same effect can be expected whether the fibers obtained by the invention are long fibers or short fibers.

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

The main uses of the fibers obtained in the present invention include staples for clothing, dry nonwoven fabrics, wet nonwoven fabrics, and the like. Of course, more than 100 fibers of the present invention may be used, or some of the fibers of the present invention may be blended with other fibers to create a nonwoven fabric or the like, and the effects of the fibers of the present invention can also be obtained. However, it is a matter of course that the effects described in the present invention cannot be fully obtained unless the fibers of the present invention are mixed in a certain proportion or more. In addition, the fibers of the present invention can be used as long fibers to provide a good texture, and are ideal for making into woven or knitted fabrics for outer garments and the like.

Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited thereto. In the hydrophilicity evaluation in the examples, water droplets are dropped on the fabric, and the spreading state is compared. A wicking property evaluation was conducted to compare the two. 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 uses orthochlorophenol 30
Measured under 'C. The saponified product of ethylene vinyl acetate copolymer was measured at 30°C using 85% hydrated phenol.

[Example 1] Polymer A was a saponified product of ethylene vinyl acetate copolymer with a degree of saponification of 99% and an ethylene content of 44 molφ, and a melt viscosity of about 120 under zero shear stress at 290°C.
A polymer having a degree of polymerization of 0 poise was used. In addition, as polymer B, the intrinsic viscosity during spinning is [η) 0.60 dt/liter, and the melt viscosity under zero shear stress at 290°C is approximately 250.
Polyethylene tele-7 tallate with 0 voids was used. Each was melt-extruded using separate extruders, weighed using a gear pump so that the weight ratio of polymer A and polymer B was 30:70, and then supplied to a spinning bag, and then
The device shown in the figure was used to spin Koenik's 4
Components A and B are formed into a layered divided polymer flow using an element static mixer, passed through a distribution plate having 12 distribution channels, and then discharged from a 24-hole round nozzle at a mouth temperature of 290°C and wound up. Melt spinning was performed at a speed of 1000 m/min.

The obtained spun yarn was drawn with a hot roller at 75°C and a hot plate at 12
Stretched at 0°C and a stretching ratio of 3.2 times, 75d-24
A multifilament of f was obtained.

The spinnability and stretchability were good and there were no problems.

Using the obtained composite fibers as warp and weft, the warp density was 8.
A plain weave fabric with a weft density of 5/ins and a weft density of 81/in was obtained. This fabric was subjected to polyalkali weight loss treatment for about 20 minutes, then dried and preset in a conventional manner, and then dyed under the following conditions. Thereafter, it was dried and finished and set using a conventional method.

The resulting plain woven fabric had a good texture similar to natural cotton fibers, which had a soft feel, bulkiness, and crispness. The fabric also had good hydrophilic properties.

[Examples 2 to 7] Using the same polymer as in Example 1, Example 2 had a composite ratio of A/B of 50/50, and Example 3 had A/B of 15/50.
85, and the other conditions were the same as in Example 1. Examples 4 and 5 were carried out under the same conditions as in Example 1 except that the number of elements in the static mixer was changed to 3 and 7, respectively. In Example 6, the number of distributions on the distribution plate was set to 8, and a round nozzle with 24 holes was used. In Example 7, the number of distributions on the distribution plate was set to 8.
The test was carried out using a 36-hole round nozzle, and the other conditions were the same as in Example 1. In all cases, fabrics with good processability, good hydrophilicity, and good texture were obtained. [Example 8.9] Ethylene content used as polymer: 30 to 70 mol%, saponified ethylene Fiberization was carried out in the same manner as in Example 1 except that the amount of copolymerization was changed. Example 8 was carried out with an ethylene content of 32 moles, and Example 9 was carried out with an ethylene content of 48 moles. In all cases, fabrics with good processability, good hand feel, and good hydrophilicity were obtained.

[Example 10] The same polymer as in Example 1 was used as the A polymer, nylon 6 with a melt viscosity of 1900 poise was used as the B polymer, and composite spinning was carried out under the same conditions as in Example 1. The yarn was continuously drawn and heat treated without winding up to obtain a multifilament drawn yarn of 24 filaments of 75 denier.

Thereafter, a woven fabric was created and dyed under the following conditions. The fabric was easy to form into fibers, had a good texture, and had good hydrophilicity.

The sample after staining was processed by a conventional method.

[Example 11] The same polymer as in Example 1 was used as the A polymer, polybutylene terephthalate with a melt viscosity of 1000 voids was used as the B polymer, and the other conditions were the same as in Example 1. Fibers were formed into 24 filaments of 75 denier. A multifilament drawn yarn was obtained. Thereafter, a woven fabric was created and dyed under the same conditions as in Example 1. The fabric was easy to form into fibers, had a good texture, and had good hydrophilicity.

[Comparative Examples 1 and 2] Using the same polymer as in Example 1, Comparative Example 1 had an A/H composite ratio of 5795, Comparative Example 2 had an A/B composite ratio of 9515, and the others were the same as Example 1. Although the experiments were carried out under the same conditions, in both cases there was a lot of oblique orientation and dropped screws during discharge from the nozzle, and the spinnability was poor. The composite shape of the obtained fiber was similar to a sea-island structure and was a common composite shape. Moreover, the obtained fabric was also featureless.

[Comparative Example 3] Using the same polymer as in Example 1, element 2 in a static mixer was carried out. Although the spinnability and post-processability were good, the composite shape was randomly different among the single fibers targeted by the present invention, and one component formed an independent island component and the other consisted of a layered divided layer. However, it was not sufficient to form a bonded structure in which the two components were unevenly distributed in a state in which fibers were mixed and randomly formed. However, the fabrics obtained were rather nondescript and rare.

[Comparative Example 4] Using the same polymer as in Example 1, a static mixer with 12 elements was used. Although the fiberization processability was good, most of the composite shapes were close to seabird structures. The resulting fibers were colored yellow-brown, which was thought to be due to a partial reaction between polymer A and polymer B, and were not suitable for use as a textile product.

[Comparative Example 5] This experiment was carried out using EVAL having a melt viscosity of 350 voids as the A polymer, but the spinnability was extremely poor due to severe slanting during spinning, screw dropping, and nozzle fouling.

[Comparative Example 6] The experiment was carried out using EVAL having a melt viscosity of 600 voids as the A polymer and polyethylene tere-7 tallate having a melt viscosity of 15,000 voids as the B polymer. During spinning, there were severe oblique angles, screws falling off, etc., and the spinnability was extremely poor.

[Comparative Examples 7 and 8] Using polymer A with a different amount of ethylene copolymerization,
The other conditions were the same as in Example 1. In Comparative Example 7, the spinnability of Polymer A was poor and the spinnability was extremely poor. In addition, when spinning continues for a long time, the gelled product of polymer A clogs the spinning filter, and at the same time,
A large amount of gelled material is mixed into the fibers, further deteriorating spinnability.

The stretchability was also very poor, making it impossible to obtain a fabric whose texture could be evaluated.

Comparative Example 8l-jA A polymer containing 80 moles of ethylene copolymer was used, and although the fiberization process was good, the texture of the obtained fabric was unsatisfactory as it had another characteristic. At the same time, the hydrophilicity was also at an insufficient level.

[Comparative Examples 9 and 10] Ethylene content used as A polymer: 30 to 70
Tests were conducted using different mol% and degree of saponification of the saponified product. Comparative Example 9 used a saponification degree of about 90%, and Comparative Example 10 used a saponification degree of about 80.

In all cases, troubles such as adhesion between single yarns occurred during the drawing process, and phenomena such as severe sticking occurred during the fabric processing process, making it impossible to obtain fabrics that could be evaluated for texture.

The conditions and results for each of the above Examples and Comparative Examples are summarized in Table 1.

(Effects of the present invention) As described above, the present invention has an ethylene content of 30% that satisfies the specific conditions.
~70 mol% of two types of polymers, a saponified product and a crystalline thermoplastic resin with a melting point of 150°C or higher, are composite-spun by a method that satisfies predetermined conditions, and the composite shape is substantially in the length direction of the fibers. To provide a novel composite filament and a composite staple which have a special composite fiber having a round shape but with random differences between single fibers, and have natural mottling similar to natural fibers, a soft texture, and good hydrophilicity. There is a particular thing.

[Brief explanation of drawings]

FIG. 1 is an example of a photograph showing the cross-sectional structure of the fiber of the present invention. FIG. 2 is a model sketch of an example of a typical composite shape of the fiber of the present invention. FIG. 3 is a sectional view showing an example of a spinneret apparatus for producing fibers of the present invention, and FIG. 4 is a view of a distribution plate of an example of the spinneret apparatus as viewed from the X- plane. Figure 5 shows 2fR reaching the distribution plate. This is a model showing the polymer composite flow of each block when the polymer composite flow is distributed radially. FIG. 6 shows an example of a common composite fiber.

Claims (1)

[Claims] 1) Ethylene content 30 to 70 mol%, degree of saponification 95%
It is a composite fiber consisting of the above saponified ethylene-vinyl acetate copolymer (A polymer) and a crystalline thermoplastic polymer (B polymer) having a melting point of 150°C or more and having fiber formability, and the weight ratio of A polymer and B polymer. starts from 10:90
90:10, and the composite shape of the A component and the B component is substantially the same in the length direction of the fiber, but varies randomly between the single fibers, and the single fiber has one component that is layered. There are two types of composite shapes: one in which a divided layer is formed, one in which one component forms an independent island component, and one in which two components are unevenly distributed to form a bonded structure. In the mixed state, the average value x of the contact length at the interface between the A component and the B component in the fiber cross section of the single fiber is expressed by the following formula (1) or (2) with respect to the average circumference y of the fiber cross section.
) A special composite fiber characterized by being expressed by the relationship shown in 1.0×a/100≦x/y≦10.0×a/100 However, when a≦b...(1) 1.0×b/100≦x/y
≦10.0×b/100 However, when b≦a... (2) a
, b are weight percentages of polymer A and polymer B, respectively. 2) The special composite fiber according to claim 1, wherein polymer B is a polyester whose main component is polyethylene terephthalate or polybutylene terephthalate. 3) The special composite fiber according to claim 1, wherein the B polymer is a polyamide whose main component is nylon 6, nylon 66, or nylon 12. 4) Ethylene content 30-70 mol%, saponification degree 95%
Each of the saponified ethylene-vinyl acetate copolymer (A polymer) and the crystalline thermoplastic polymer (B) having a melting point of 150°C or higher and having fiber formability has a melt viscosity under zero shear stress at 290°C. It is more than 400 poise,
Moreover, the melt viscosity η_A of the A polymer and the melt viscosity η_B of the B polymer satisfy the following formula (3). η_B≦20×η_A (3) The A polymer and the B polymer are melted separately. extrusion, and then within 5 minutes of the start of contact between these two polymers, the weight ratio of A:B is in the range of 10:90 to 90:10, passed through a static mixer immediately before spinning, into a layered composite form, and then Thereafter, the layered polymer stream is divided and distributed again in a radial manner into a number smaller than the number of nozzle holes, and then spun using a multi-hole spinning nozzle. 5) The method for producing a special composite fiber according to claim 4, wherein the B polymer is a polyester whose main component is polyethylene terephthalate or polybutylene terephthalate. 6) The method for producing a special composite fiber according to claim 4, wherein the B polymer is a polyamide whose main component is nylon 6, nylon 66, or nylon 12.