TW202212658A - Composite fiber, hollow fiber and multifilament - Google Patents

Abstract

The present invention relates to a composite fiber wherein: two or more kinds of polymers, which are different from each other in the dissolution rate in a solvent, are stacked from the center of the fiber in the direction toward the fiber surface in a cross-section of the fiber; the innermost layer comprising the center of the fiber contains an easily soluble polymer; and two or more kinds of poorly soluble polymers, which have different melting points, are unevenly distributed in at least one layer other than the innermost layer.

Description

Composite fibers, hollow fibers and multifilaments

The present invention relates to conjugate fibers, hollow fibers, and multifilaments suitable for use as textile materials for clothing having excellent wearing comfort.

Synthetic fibers composed of polyester, polyamide, etc. have excellent mechanical properties and dimensional stability, and are therefore widely used in clothing applications to non-clothing applications. However, today's diversified human life demands a better life and expects fibers with higher tactile sensations and functions.

Especially in textile materials for clothing that come into contact with human skin, excellent wearing comfort is required in many cases, and fibers having a texture that is directly related to human wearing feel like natural fibers are strongly demanded. The reason for this is that natural fibers such as hemp, wool, cotton, and silk have an excellent balance of texture and function, and the complex appearance and texture woven from these fibers can make people feel attractive and luxurious.

Focusing on the technical examples that can achieve a texture with a good feel by such a natural fiber, various proposals have been made to form a void structure containing air in the fabric by focusing on the cross section of the synthetic fiber, thereby showing a moderate rebound and fluffy. soft texture and other technologies.

In the hollow fiber proposed in Patent Document 1, a hollow fiber obtained by using a hollow spinning nozzle is subjected to a false twisting process, and the hollow cross-section is deformed and flattened by imparting crimping, thereby imparting a flat hollow cross-section similar to cotton. Shape and twist. The flat hollow fiber can obtain a cotton-like texture with a fluffy and bouncy feeling.

Furthermore, the hollow fiber proposed in Patent Document 2 is a core-sheath composite fiber in which an alkali-soluble polymer is used as a core component, an alkali-hardly soluble polymer is used as a sheath component, and a part of the core component is exposed on the fiber surface. False twisting is performed, and then the core component is eluted by alkali treatment, thereby forming a C-shaped cross-sectional shape having a continuous hollow portion and an opening portion in the fiber axis direction. When the core-sheath composite fiber is made into a woven fabric, it can have a light-weight feeling and a moderate rebound feeling due to the effect of the C-shaped hollow, and can provide a soft texture and the like.

Furthermore, the bulky and lightweight multifilament proposed in Patent Document 3 has a fiber cross section in which an outermost layer, an intermediate layer, and an innermost layer are formed by laminating two or more kinds of polymers having different dissolution rates in a solvent in the cross-sectional direction. The polymer forming the outermost layer and the innermost layer is a readily soluble polymer, and the intermediate layer is formed by mixing two or more types of monofilaments having different cross-sectional shapes. The bulky and lightweight multifilament system is composed of easily soluble polymer not only inside the fiber but also on the surface of the fiber, so that after the soluble polymer is eluted, voids can be formed inside and outside the fiber, and different fibers are mixed after the dissolution. The cross-section can prevent the inter-fiber voids from collapsing, and can form a fabric with a soft texture in addition to lightness and bulk. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 54-151650 [Patent Document 2] Japanese Patent Laid-Open No. 01-052839 [Patent Document 3] Japanese Patent Laid-Open No. 2019-167646

(The problem that the invention intends to solve)

As in Patent Document 1, if a hollow fiber is subjected to a false twisting process to provide a void structure inside and outside the fiber, it is possible to reproduce a texture like natural fiber cotton to some extent. However, the technical idea of Patent Document 1 is that fibers are densely bundled by false twisting, and the hollow portion is collapsed and deformed, and when worn as clothing, there is a case where a comfortable bulky or bouncy texture is insufficient.

Furthermore, as in Patent Document 2, a method of applying false twisting to a core-sheath composite fiber having an alkali-soluble polymer as a core component and an alkali-insoluble polymer as a sheath component is performed by weaving and knitting. After the alkali treatment is performed, the core component can be eluted to form a hollow portion, so that the hollow portion does not collapse due to the false twisting process, and a high hollow ratio and inter-fiber voids in a crimped form can be formed. However, in order to prevent uneven elution of the core component, a C-shaped cross-sectional shape with large openings may not only cause the adjacent fibers to get caught in the openings and the texture will become stiff, but also feel lightweight due to continuous use. with a reduced sense of rebound.

In addition, both Patent Document 1 and Patent Document 2 adopt a false twist process in which a multifilament yarn is subjected to heat setting in a state where the multifilament is twisted, and then untwisted to give crimping. Therefore, it is easy to cause fatigue due to crimping due to heat treatment during advanced processing, and there is a case where a comfortable bulky feeling when worn as clothing is insufficient. In addition, because the crimp of each fiber in the multifilament is uniform, the texture obtained when used as a textile raw material is also monotonous. Other materials of fiber are mixed fiber, etc.

On the other hand, as in Patent Document 3, a method of forming inter-fiber voids by elution of the fiber surface is effective from the viewpoint of flexibility, but suppresses the collapse of inter-fiber voids obtained by mixing different fiber cross-sections. There is a limit to the effect, and it is difficult to say that it can show the thick inter-fiber space that can feel fluffy.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to provide: by controlling the void structure inside and between fibers, it is suitable for obtaining a soft texture with moderate rebound and fluffy texture and excellent wearing comfort. Raw materials of composite fibers, hollow fibers and multifilaments. (Technical means to solve problems)

The object of the present invention is achieved by the following means. (1) a composite fiber, which is attached to the cross section of the fiber, and is laminated with two or more kinds of polymers having different dissolving velocities to the solvent from the center of the fiber toward the surface of the fiber; The innermost layer comprising the above-mentioned fiber center contains a readily soluble polymer; In at least one layer other than the innermost layer described above, two types of poorly soluble polymers with different melting points are distributed unevenly. (2) The conjugate fiber according to (1), wherein, in the cross section of the fiber, the relationship between the inscribed circle diameter RA and the circumscribed circle diameter RB of the fiber is 1.2≦RB/RA≦2.4. (3) The conjugate fiber according to (1) or (2), wherein, in the cross section of the fiber, the easily soluble polymer system is continuous from the center of the fiber to the surface of the fiber, and the fiber is connected widely less than 10% of the diameter. (4) The conjugate fiber according to any one of (1) to (3), wherein, in the fiber cross section, the outermost layer contains the easily soluble polymer. (5) A hollow fiber in which the easily soluble polymer is removed from the conjugate fiber according to any one of (1) to (4). (6) a multifilament, which is a multifilament containing flat hollow fibers; The coefficient of variation CV of the rotation angle of the long axis of the flat hollow fiber is 15 to 50%. (7) The multifilament according to (6), wherein the flatness of the cross-section of the flat hollow fiber-based fiber is 1.2 or more. (8) The multifilament according to (6) or (7), wherein the flat hollow fiber is composed of at least two kinds of polymers having different melting points in the fiber cross section. (9) The multifilament according to any one of (6) to (8), wherein the flat hollow fiber has an opening from the center of the fiber toward the fiber surface; The width of the above-mentioned opening is 10% or less of the fiber diameter. (10) A fiber product containing, in part, the conjugate fiber according to any one of (1) to (4), the hollow fiber according to (5), or any one of (6) to (9). Multifilament as described. (Compared to the efficacy of the prior art)

The conjugated fibers, hollow fibers and multifilaments of the present invention have the above-mentioned characteristics, and can densely control the void structure between the fibers and between the fibers, and can obtain a soft texture with a moderate rebound feeling and a bulky feeling and excellent wearing comfort. Textile raw materials.

Hereinafter, the preferred embodiments of the present invention will be described in detail.

Analysis of the void structure of cotton, which has been widely developed as a natural material with a fluffy and soft texture, shows that in addition to the hollow portion inside the flat fibers, there are large and small inter-fiber voids. This phenomenon is caused by the twist of each fiber in cotton. By bundling the fibers with the twist, complex voids and irregularities will be formed when used as textile raw materials, and it is believed that a specific tactile and texture.

In order to realize the formation of such complex voids unique to nature, the inventors of the present invention have conducted intensive research and found that by performing high-level processing such as weaving and then making the fibers appear crimped, twisting the fibers bundled in a plurality of branches in the fabric can be achieved. There are inter-fiber voids of various sizes. In addition, by elution of the readily soluble polymer inside the fiber to form a hollow portion inside the fiber, a complex void structure that is difficult to obtain with conventional synthetic fibers and processed yarns utilizing the same can be achieved, and the so far achieved There is no moderate rebound feeling and soft texture with fluffy feeling, and this situation becomes the core of the present invention.

Specifically, the requirements of the present invention are that in the cross section of the fiber, two or more kinds of polymers having different dissolution rates with respect to the solvent are laminated from the center of the fiber toward the surface of the fiber, and the innermost layer including the center of the fiber contains an easily soluble polymer two kinds of poorly soluble polymers with different melting points exist unevenly in at least one layer other than the innermost layer.

In the present invention, the polymer having a relatively fast dissolving rate in the solvent used for the dissolving treatment is referred to as a readily soluble polymer, and the polymer having a relatively slow dissolving rate is referred to as a poorly soluble polymer. In addition, considering the simplification of the dissolution treatment and the shortening of the time during high-level processing, the dissolution rate ratio (easy-to-dissolve polymer/low-to-dissolve polymer) is preferably 100 or more and more based on the poorly soluble polymer. More than 1000 of the best system. If the dissolving rate ratio is 1000 or more, the dissolving treatment can be completed in a short time, so in addition to increasing the step rate, the poorly soluble polymer is not degraded unnecessarily, and a higher-quality fabric can be obtained.

In the composite fiber of the present invention, in order to be able to stably form a hollow portion inside the fiber without being affected by weaving or the like, it is necessary to laminate 2 materials having different dissolving rates with respect to the solvent in the fiber cross section from the fiber center toward the fiber surface. more than one polymer, and the innermost layer including the fiber center contains a readily soluble polymer. Moreover, it is preferable that this innermost layer consists of an easily soluble polymer.

When forming the textile raw material, by stably forming a hollow part inside the fiber, not only the fluffy and light feeling of the textile raw material can be improved, but also by the existence of an air layer inside the fiber, each fiber can have a moderate rebound feeling. Softly deformed to obtain a soft texture with moderate rebound feeling and bulkiness, which is the object of the present invention.

Furthermore, when the hollow ratio inside the fiber is increased, a lighter feeling and softness can be clearly felt. Therefore, in the conjugate fiber of the present invention, the area ratio occupied by the innermost layer including the fiber center is preferably 10% or more. , Better than 20%. In addition, the higher the area ratio of the innermost layer, the better it is from the viewpoint of light weight, but on the other hand, the strength reduction and the collapse of the hollow part are likely to occur due to excessive elution of the innermost layer, which impairs the feeling of rebound. Therefore, the substantial upper limit of the area ratio is 50%.

The key point of the composite fiber of the present invention is that after high-level processing such as weaving is performed, the fiber exhibits a crimped shape. By the fibers in the fabric being crimped and twisted respectively, the adjacent fibers and crimped forms can be entangled to present inter-fiber spaces of various sizes. It has functions such as water absorption and quick-drying due to the capillary phenomenon of the voids between the fine fibers, and stretchability due to the coiled crimping form.

When high-level processing such as weaving is performed to make the fibers crimped, it is preferable to use a composite cross-section with latent crimping properties that are crimped by heat treatment, and the cross-sections of the fibers are arranged in such a way that their centers of gravity are different. For polymers with poor shrinkage, after heat treatment, the fibers will be greatly bent toward the side of the high-shrinkage polymer, and by continuing this situation, a three-dimensional helical structure can be formed.

That is, in order to achieve the object of the present invention, it is important to arrange polymers with different shrinkage differences in the fiber cross section so as to maintain a sufficient distance between the centers of gravity. In the conjugate fiber of the present invention, at least one layer other than the innermost layer is required. There are two kinds of insoluble polymers with different melting points.

Here, in the present invention, the term “insoluble polymers with different melting points” means that in the straight line passing through the center of the fiber and dividing the fiber cross section into two equal parts, the following straight lines exist: In the cross section, the area ratio of the insoluble polymer on the high melting point side and the insoluble polymer on the low melting point side is 100:0~70:30 in any fiber cross section, and is 100:0~70:30 in the other fiber cross section. A straight line in the range of 30:70 to 0:100 (for example, straight line I in Fig. 1(a)).

The composite structure of the composite fiber of the present invention is not particularly limited on the premise that poorly soluble polymers having different melting points are present. The composite structure can be, for example, the side-by-side type as shown in Fig. 1(a) and Fig. 1(c), the sea-island type as shown in Fig. 1(b), the eccentric core-sheath type as shown in Fig. 1(d), etc. . Among these, from the viewpoint of increasing the distance between the centers of gravity and increasing the crimping force, a side-by-side type in which poorly soluble polymers having different melting points are completely separated is preferable.

When joined in a side-by-side type, since the interface of the poorly soluble polymers with different melting points is small, the distance between the centers of gravity of the polymers in the composite cross-section can be expanded to the maximum limit, and the curling force can be exerted to the maximum limit. In addition, it is preferable that the crimped form has a fine spiral structure, since excellent stretchability can also be imparted, and pressure-free wearing comfort can be obtained with a fabric having moderate expansion and contraction.

In the fiber cross section of the composite fiber of the present invention, the relationship between the inscribed circle diameter RA of the fiber and the circumscribed circle diameter RB is preferably 1.2≦RB/RA≦2.4.

Here, the "inscribed circle diameter RA" and "circumscribed circle diameter RB" of the present invention are obtained by encapsulating the fibers with an entrapment agent such as epoxy resin, and using scanning electron microscopy for the cross-section of the fibers in the direction perpendicular to the fiber axis. The microscope (SEM) was obtained by taking a magnification image at a magnification that can observe fibers of 10 or more single filaments.

The fibers randomly selected in the same image from each of the captured images are analyzed using image analysis software, and the fibers are incised at at least two points (eg, a1 and a2 in Fig. 2(a)) on the surface of the fibers, and exist only in In the range where the circumference of the inscribed circle inside the fiber does not intersect with the fiber surface, the diameter of the circle with the largest diameter (for example, A in Fig. 2(a)) is calculated, and the result is applied to 10 monofilaments accordingly. A simple number average was obtained, and the value rounded up to the decimal point was used as the inscribed circle diameter RA.

Furthermore, in the range where the circumference of the circumscribed circle that is circumscribed with the fiber surface at at least two points (for example, b1 and b2 in Fig. 2(a)) and exists only outside the fiber and does not intersect the fiber surface, it is calculated that the The diameter of the circle with the smallest diameter (for example, B in Fig. 2(a) ) is obtained by calculating the simple number average from the results performed on 10 monofilaments, and the value rounded to the nearest decimal point is set as the circumscribed circle diameter RB.

In addition, the so-called "RB/RA" is calculated by dividing the RB obtained by the above-mentioned fibers by the RA, and then calculating the simple number average of the results performed on 10 monofilaments, and dividing the second decimal point. The rounded value is set as RB/RA.

The cross-sectional shape of the conjugated fiber of the present invention is not limited, but the key point is that after high-level processing such as weaving, the fibers are respectively crimped and twisted, and adjacent fibers are entangled with the crimped shape to present inter-fiber spaces of various sizes. From this point of view, if the cross-section of the fiber is of a variant cross-section, the inter-fiber space that occurs when the fiber is twisted can be more complicated and increased, so the ratio of the inscribed circle diameter RA of the fiber to the circumscribed circle diameter RB RB/ RA (variability) is preferably 1.2 or more.

Furthermore, if RB/RA is set to 1.5 or more, the crimping phase between adjacent fibers is not uniform, the inter-fiber space can be stably formed, and the fabric can have a uniform appearance without unevenness such as streaks. can be described as a better range. In addition, although the larger RB/RA is, the more stable the inter-fiber space can be formed, but on the other hand, not only the light reflected by the fiber surface may be dazzling depending on the situation, but also due to the edge cross-sectional shape. When the flexural rigidity is increased more than necessary and the flexibility is impaired, the substantial upper limit of RB/RA is 2.4.

When the cross-sectional shape of the conjugated fiber of the present invention is a variant cross-section, for example, all variant cross-sections such as flat shape, multi-lobed shape, polygonal shape, gear shape, flower shape, and star shape can be adopted. From the viewpoint of rebound feeling and flexibility, the fiber shape is preferably a flat shape as shown in FIG. 2( a ) or a multi-lobed shape as shown in FIG. 2( b ). With the flat shape shown in Fig. 2(a), a sense of rebound due to high bending rigidity can be obtained when bending along the plane perpendicular to the long axis of the flat cross section, and when bending along the plane perpendicular to the short axis, the Softness due to low flexural rigidity is obtained, so that a texture having moderate rebound feeling and softness can be obtained.

Furthermore, in the case of a multifilament yarn, when the fibers are twisted in a crimped form, not only the inter-fiber space due to the three-dimensional obstacle increases, but also the moderate rebound feeling and bulkiness can be further improved, and due to the partiality of the long axis direction of the flat fiber cross section. Alignment, when the textile material is made, the difference between the gap and the unevenness occurs at the aligned and unaligned positions of the cross-sectional long axis direction between the adjacent fibers, and complex voids and unevenness can be formed between the fibers. Therefore, the flat shape is still preferable from the viewpoint of being able to express a touch specific to a natural product.

On the other hand, if the multi-lobed shape as shown in FIG. 2( b ) is used, by imparting irregularities to the fiber surface, it is possible to suppress glare due to light scattering and to improve the water absorption and quick-drying properties due to the voids between the fine fibers. From the point of view, it is better. However, if the number of the concavo-convex portions is too large, the interval between the concave-convex portions becomes narrow, and this effect gradually decreases. Therefore, in the present invention, the substantial upper limit of the convex portions included in the multi-lobed shape is 20.

Furthermore, if it is a flat shape and a multi-lobed shape as shown in FIG. 2( c ), the characteristics of the flat shape and the multi-lobed shape can be combined. Therefore, from the viewpoint of having a soft texture with moderate rebounding and bulkiness when used as a textile material, which is the object of the present invention, and combining functions such as water absorption and quick-drying, it is more preferably flat and multi-lobed.

In the fiber cross section of the composite fiber of the present invention, preferably, there is a connecting portion in which the easily soluble polymer is connected from the center of the fiber to the surface of the fiber.

In the conjugated fiber of the present invention, in order to stably form a hollow portion inside the fiber, it is necessary to elute the easily soluble polymer in the innermost layer. Then, since the easily soluble polymer is gradually removed from the surface of the fiber by the dissolution and removal by the solvent, if a connecting portion from the fiber surface to the innermost layer can be provided, not only can the easily soluble polymer be dissolved in a short period of time. The water absorption and water retention caused by the capillary phenomenon can also be imparted to the opening formed by the dissolution of the easily soluble polymer. From this point of view, the readily soluble polymer is preferably connected from the center of the fiber to the surface of the fiber.

It is preferable that the communication width by the easily soluble polymer is 10% or less of the fiber diameter. Here, the "fiber diameter" of the present invention refers to encapsulating the composite fibers with an encapsulating agent such as epoxy resin, and with respect to the fiber cross-section in the direction perpendicular to the fiber axis, 10 or more monofilaments can be observed using a scanning electron microscope (SEM). The magnification of the fiber is obtained by taking an image. Fibers were randomly selected within the same image from each of the captured images, the diameter was measured in μm to the first decimal place, and a simple number average was obtained from the results performed on 10 monofilaments, and the first decimal place was rounded off. The value of is set as the fiber diameter (μm). Here, when the fiber cross section in the direction perpendicular to the fiber axis is not a perfect circle, the area is measured, and the diameter value obtained by converting to a perfect circle is used.

Furthermore, when obtaining the connection width of the present invention, firstly, the composite fibers of the present invention are encapsulated by occluding agents such as epoxy resins, and the cross-section of the fibers in the direction perpendicular to the fiber axis is analyzed by a transmission electron microscope (TEM) according to the The images were taken at a magnification of more than 10 fibers. Then, for the composite fiber of the obtained image, when the easily soluble polymer is connected from the center of the fiber to the surface of the fiber, the image analysis software is used for analysis, whereby the distance between the fibers passing through the center G of the fiber and parallel to the connecting part is analyzed. The shortest width calculated in units of μm within the width W (eg, W in FIG. 3( c )) of the connecting portion in the vertical direction of the straight line S (eg, S in FIG. 3( c )). A simple number average was obtained from the results performed on 10 monofilaments in this manner, and the value rounded to the second decimal place was set as the "connection width".

In addition, calculate the value obtained by dividing the segment width obtained by each filament by the fiber diameter, and multiplying it by 100. From the result of applying this to 10 filaments, a simple number average is obtained, and the decimal point is calculated. The following rounded-off value is the ratio (%) of the connection width to the fiber diameter.

If the communication width formed by the easily soluble polymer is set to be 10% or less of the fiber diameter, it is possible to prevent excessive expansion of the opening formed after removing the easily soluble polymer, which may lead to the engagement between fibers or the deviation of the opening. The collapse of the hollow part caused by the displacement can prevent damage to the moderate rebound feeling and the soft texture with bulkiness.

Furthermore, if the communication width is set to be 5% or less of the fiber diameter, not only can the fibrillation caused by the abrasion of the fibers caused by the openings formed after the elution of the easily soluble polymer be suppressed, but also the functional agent is applied. In the case of post-processing such as coating, the functional agent entering the hollow part can be prevented from falling off due to washing, etc., and the performance durability of the functional agent can be greatly improved, so it belongs to a better range. However, if the communication width is too narrow, the easily soluble polymer is not easily dissolved, so the substantial lower limit of the communication width is 1% of the fiber diameter.

In the fiber cross section of the composite fiber of the present invention, it is preferable that the outermost layer contains a readily soluble polymer, and it is more preferable that the outermost layer is composed of a readily soluble polymer. Here, the term "outermost layer" in the present invention refers to a layer including 80% or more of the fiber surface.

If the outermost layer is made of a readily soluble polymer, the inter-fiber space will naturally expand when the easily soluble polymer is removed, and flexibility due to the fibers fixed at the knitted fabric bundling points becoming movable, and high voids can be obtained. The effect of reducing the apparent density caused by the rate and improving the feeling of lightness.

From this point of view, in the fiber cross section of the composite fiber, the higher the area ratio of the outermost layer, the better. If the area ratio is set to 10% or more, flexibility and lightness can be sufficiently obtained regardless of the fabric structure. The effect of improving the sense of volume, so it belongs to the better range. However, if the area ratio is too high, the rebound feeling may be reduced due to the reduction in bending rigidity, so the practical upper limit is 30%.

Using the composite fiber of the present invention, after first performing high-level processing such as weaving, and then heat treatment to make it appear crimped, and then removing the easily soluble polymer in the innermost layer, a hollow material composed of only a poorly soluble polymer can be obtained. A fiber, and a multifilament composed of the hollow fiber. From the multifilament yarn, a soft texture with moderate rebound and bulkiness due to its specific fiber cross-sectional shape and inter-fiber space, combined with functions such as water absorption, quick-drying, and stretchability, can be obtained as a textile material excellent in wearing comfort .

Furthermore, in order to maximize the peculiar touch and texture caused by the formation of complex voids and concavities and convexities that are unique to natural products when making multifilament yarns, the inventors of the present invention have conducted intensive research and found that by controlling the thickness of the flat fibers. By twisting and appropriately integrating the long-axis direction of the cross-section, complex voids and irregularities that are difficult to obtain in conventional synthetic fibers and processed yarns utilizing them can be formed.

That is, in a multifilament composed of flat fibers without twist, since all the major axis directions of the fiber cross-sections are aligned, the voids obtained are small, and the unevenness is also flat. On the other hand, in the case of a multifilament composed of flat fibers to which twists have been imparted by false twisting, since the twist per fiber is uniform, and the major axis directions of the cross-sections are respectively oriented in different directions during untwisting, it is possible to obtain the twist. There are voids and bumps, but there are cases where it becomes monotonous.

On the other hand, if the twist is controlled so that the long axis direction of the cross section of the flat fibers in the multifilament is partially aligned, when it is used as a textile material, the long axis direction of the cross section between adjacent fibers is aligned, and the position is not aligned. Differences between voids and concavities and convexities are generated, and complex voids and concavities and convexities can be formed between fibers. In this way, in addition to the unique tactile feeling unique to natural products, hollow parts are provided inside the fibers, and the complex voids or concavities and convexities between the fibers can be combined to present a soft texture with moderate rebound feeling and bulkiness.

The present invention is constituted by designing fibers based on this concept. Specifically, the multifilament system of the present invention includes flat hollow fibers. The multifilament of the present invention is preferably composed of flat hollow fibers, and the requirement of the present invention is that the coefficient of variation CV of the rotation angle of the long axis of the flat hollow fibers in the multifilament is 15 to 50%.

The important point of the present invention is that the fibers constituting the textile raw material are flat hollow fibers.

If the fiber cross section is a flat cross section as shown in Fig. 5(a), when bending along the plane perpendicular to the long axis of the flat cross section, a sense of rebound due to high bending rigidity can be obtained. When bending, flexibility due to low bending rigidity can be obtained, so that a texture having both moderate rebound feeling and softness can be obtained.

In order to exhibit the above-mentioned effects, the flatness is preferably 1.2 or more, and more preferably the flatness is 1.5 or more. By setting it as this range, the interfiber space|gap is formed by the three-dimensional obstacle when a flat hollow fiber is twisted, and a bulky feeling can also be obtained when it is used as a textile raw material.

In addition, the higher the flatness, the more stable the formation of inter-fiber spaces, but on the other hand, not only does the light reflected from the surface of the fibers may cause uneven appearance (dazzle) depending on the situation, there are also reasons for this. The cross-sectional shape with an edge may increase the bending rigidity more than necessary and impair the flexibility, so the upper limit of the flatness of the present invention is set to 2.4.

Here, the so-called "flatness" in the present invention refers to the use of epoxy resin and other entrapment agents to encapsulate the multifilament, and for the cross section of the fiber in the direction perpendicular to the fiber axis, 10 monofilaments can be observed using a scanning electron microscope (SEM). The above fiber magnifications were obtained by taking images. Fibers are randomly selected in the same image from each captured image, and analyzed using image analysis software. As shown in Fig. 5(a), the two points (c1, c2) that are farthest from any point on the periphery of the fiber are connected. The straight line (c1-c2) of , is set as the major axis, the straight line (d1-d2) passing through the midpoint of the major axis and orthogonal to the major axis is set as the minor axis, and the length of the major axis divided by the length of the minor axis is calculated. Such calculation was performed for 10 fibers, the simple number average of the results was obtained, and the value rounded to the second decimal place was defined as the flatness.

Furthermore, by having hollow parts inside the fibers, not only the bulkiness and lightness of the textile material can be improved, but also each fiber has a moderate rebound feeling and can be deformed softly, which can make the effect caused by the flat cross section more obvious.

Furthermore, if the hollow ratio inside the fiber is increased, bulkiness and lightness can be clearly felt. Therefore, in the flat hollow fiber in the multifilament of the present invention, the area ratio of the hollow portion including the center of the fiber is preferably 10%. above. In addition to increasing the porosity of the fiber bundle and making the feeling of light weight more pronounced, when making the fabric more flexible, the area ratio of the hollow portion is more preferably 20% or more. In the case of this range, in the case of the aforementioned flat cross-section, the deformation of the single fiber produces directionality, and by exhibiting the twisted shape characteristic of the present invention, the fiber bundle becomes a complex deformation, which is unprecedented in conventional silk processing. The feel is good to the touch.

It is preferable from the viewpoint that the higher the area ratio of the hollow portion, the more obvious the lightness of the fiber bundle and the textile material. However, when the thickness of the polymer constituting the fiber is reduced, the strength is reduced and the hollow part is likely to collapse, and there is a possibility that a part of the good feeling of rebound which is the object of the present invention cannot be fully exhibited. Therefore, the hollow part of the present invention is The substantial upper limit of the area ratio of the portion is set to 50%.

Here, the so-called "hollow ratio" in the present invention refers to the use of epoxy resin and other entrapment agents to encapsulate the multifilament, and for the fiber cross-section in the direction perpendicular to the fiber axis, 10 monofilaments can be observed by scanning electron microscope (SEM). The above fiber magnifications were obtained by taking images. When fibers randomly selected in the same image from each of the captured images have a hollow portion such as H in Fig. 5(a), use image analysis software to analyze and obtain the outer shape of the fiber including the hollow portion. The area and the hollow area were calculated by dividing the hollow area by the area obtained from the outer shape of the fiber including the hollow, and multiplying the value by 100. The simple number average was calculated|required from the result performed with respect to 10 fibers in this way, and the value rounded to the 1st decimal place was made into the hollow ratio (%).

Furthermore, the fiber cross-sectional shape is preferably combined with a cross-sectional shape having a convex portion on the fiber surface (a multilobal shape, a polygonal shape, a gear shape, a flower shape, a star shape, etc.) in addition to the flat shape shown in Fig. 5(a). This is because the appearance unevenness (dazzle) caused by light scattering can be suppressed and the water absorption caused by the voids between the fine fibers can be improved. However, if the number of convex portions is too large, this effect is gradually reduced, so the substantial upper limit of the convex portions is limited to 20.

In the present invention, if the twist is controlled in such a way that the cross-sections of the flat fibers in the multifilament are partially aligned in the long-axis direction, when used as a textile material, between adjacent fibers, the cross-section long-axis directions are aligned and misaligned. The difference between voids and bumps is created. As a feature of the present invention, the complex voids formed between the fibers and the requirements for the formation of irregularities on the surface of the textile raw material, the main point is that the coefficient of variation CV of the rotation angle of the long axis of the flat hollow fibers in the multifilament is 15~ 50%.

In the present invention, the "variation coefficient of the rotation angle of the long axis" refers to the cross-section of the fabric perpendicular to the longitudinal direction of the fabric and the direction of the multifilament fiber axis in the fabric composed of the multifilament, using a scanning electron microscope (SEM) Obtained by taking images at a magnification at which more than 20 fibers can be observed. In the fiber in the obtained image, if the fiber has a flat cross-section, it is analyzed using image analysis software, and as shown in Fig. 5(b), a straight line ( c1-c2) are set as the long axis, and the straight line passing through the midpoint of the long axis of the flat hollow fiber and parallel to the bottom of the captured image is rotated counterclockwise around the midpoint of the long axis, and the rotation angle when the long axis and the slope of the straight line are consistent is evaluated. (θ).

This evaluation was performed on 20 fibers ((1) to (20) in Fig. 5(b)) randomly selected from the multifilaments of the same image, and the standard deviation and average value of the results were calculated to calculate the standard deviation. The deviation is divided by the average value and multiplied by a value of 100, and the value rounded to the first decimal place is set as the coefficient of variation CV (%) of the rotation angle of the major axis.

In the present invention, the coefficient of variation CV of the rotation angle of the long axis of the flat hollow fibers in the multifilament must be 15% or more. By setting this range, the surface of the textile raw material appears due to the misalignment of the long axis direction of the cross section. The unevenness of the cloth will present a refreshing touch caused by the large friction fluctuation when it touches the surface of the cloth. In addition, complex voids are formed between the fibers, and in cooperation with the hollow portion inside the fibers, a soft texture with moderate rebound feeling and bulky feeling can also be exhibited.

The "variation coefficient CV of the rotation angle of the long axis" of the present invention is preferably 25 to 40%. If it is within this range, the distance between the concave and convex is narrowed, and not only the refreshing touch tends to be obvious, but also due to the increase of the space between the fibers, it is regarded as a The apparent density of the fabric is reduced, and it also has the effect of increasing the fluffy. On the other hand, if the coefficient of variation CV is too large, the unevenness will be too fine and the frictional variation will be reduced, resulting in a monotonous touch. Therefore, the substantial upper limit of the coefficient of variation CV is 50%.

For controlling the coefficient of variation of the rotation angle of the long axis of the flat hollow fibers in the multifilament, for example, a method of producing flat hollow fibers with different twists by false twisting or the like, and then mixing and bundling them by interlacing or the like can be considered. In addition, if a flat hollow fiber having latent crimping properties such as being crimped by heat treatment is used, and the flat hollow fiber can be in a crimped state after high-level processing such as weaving, when the crimping occurs, localized formation of The crimp phase difference between fibers can easily make the coefficient of variation CV of the rotation angle of the long axis of the flat hollow fiber in the multifilament within the target range.

From this point of view, in the flat hollow fiber in the multifilament of the present invention, it is preferable that the fiber cross-section is made of at least two kinds of polymers having different melting points in order to be a fiber having latent crimpability that can be crimped by heat treatment. composition. If it is composed of polymers with different melting points, the fibers will bend toward the high shrinkage polymer after heat treatment due to the difference in shrinkage caused by the difference in melting point.

In order to improve the crimping force, it is better to set the composite cross-section so that the polymers with different melting points maintain a sufficient distance between the centers of gravity. From this point of view, it is better to join the polymers with different melting points as shown in Fig. 6(a). side-by-side type shown. That is, since the interface of the polymers with different melting points is small, the distance between the centers of gravity between the polymers of the composite cross-section can be enlarged to the maximum limit, and the curling force can be exerted to the maximum limit.

Furthermore, by forming a fine spiral structure by the crimped form, excellent stretchability can also be imparted, and a pressure-free wearing comfort can be obtained by using a fabric with moderate expansion and contraction.

Furthermore, the flat hollow fibers in the multifilaments are particularly preferably set to have a random cross-sectional shape in the direction (angle) of the joining surfaces of the polymers with different melting points in each single fiber (the four types shown in FIG. 9 are examples of the cross-sectional shape). ), using the difference in the distance between the centers of gravity, the crimping shape presented by the heat treatment can be different for each single fiber, and the crimping phase difference between the fibers can also be improved. With this effect, the coefficient of variation (CV) of the rotation angle of the long axis of the flat hollow fiber in the multifilament can be brought closer to the optimum range.

In the multifilament of the present invention, it is preferable that the coefficient of variation of the rotation angle of the long axis of the flat hollow fiber in the multifilament is within the target range, and the hollow portion of the flat hollow fiber can be stably formed without being affected by the structure such as weaving. The following conjugated fibers were used. That is, it is preferable to use two or more kinds of polymers having different dissolving rates with respect to the solvent layered from the center of the fiber toward the surface of the fiber in the cross-section of the fiber. At least one layer other than the layers is a conjugate fiber composed of two types of poorly soluble polymers having different melting points.

After high-level processing such as weaving is performed on the composite fiber, a crimped shape is obtained by heat treatment, and the easily soluble polymer in the innermost layer is removed, so that the hollow part can be stably formed without collapsing during high-level processing. The multifilament formed by the flat hollow fiber can be used to exhibit crimping, and the coefficient of variation of the rotation angle of the long axis of the flat hollow fiber in the multifilament can be set within the target range.

The flat hollow fibers in the multifilament of the present invention preferably have a crimped form in which the number of crimped threads is 5 threads/cm or more when the crimped form is formed by heat treatment.

Here, the so-called "number of crimped teeth" in the present invention can be obtained by the following method. That is, in a fabric composed of multifilaments, the multifilaments are extracted from the fabric so that plastic deformation does not occur, and one end of the multifilaments is fixed. After applying a load of 1 mg/dtex to the other end for 30 seconds or more, marking was performed at any point where the distance between two points was 1 cm in the direction of the fiber axis of the multifilament.

Then, the fibers were separated from the multifilaments so that no plastic deformation would occur, and the distance between the marks marked in advance was adjusted to the original 1 cm, and the fibers were fixed on the mounting glass. An image of this sample was taken with a digital microscope at a magnification that enables observation of a 1 cm mark. In the photographed image, when the multifilament has the crimped shape of the fiber twist as shown in Fig. 11, the number of crimped teeth existing between the marks is obtained. This operation was performed for 10 fibers made of the same polymer, and a simple number average was obtained from the results, and the numerical value rounded to the first decimal place was set as the number of crimping teeth (teeth/cm).

In the crimped form with a crimping number of 5 threads/cm or more, the rotation of the long axis of the flat hollow fibers in the multifilament can be made by locally generating a crimp phase difference between fibers when crimping occurs. The variation coefficient CV of the angle is set within the target range.

In addition, if the number of crimps is set to 10 threads/cm or more, not only the inter-fiber space is increased by the effect of the excluded volume between the fibers, but also the bulkiness improvement effect is obtained, and the crimp form becomes a fine spiral structure, so that stretching can also be imparted. sex, so it belongs to the better range.

From the viewpoint of imparting stretchability, it is preferable to increase the number of crimps, but if the number of crimps is too large, the coefficient of variation CV of the rotation angle of the long axis of the flat hollow fibers in the multifilament also increases, depending on the The texture of weave or the like may become monotonous to the touch. Therefore, in the present invention for the purpose of presenting a better tactile sensation, the substantial upper limit of the number of crimped teeth is 50 teeth/cm.

In the flat hollow fiber in the multifilament of the present invention, it is preferable to have an opening from the center of the fiber toward the surface of the fiber. If there is an opening connected to the hollow part, not only the water absorption is exhibited by the capillary phenomenon of the opening, but also by increasing the surface area of the fiber, the effective area of the functional agent is also increased when post-processing such as coating the functional agent is performed. Improve the performance of functional agents.

In addition, the width of the opening is preferably 10% or less of the fiber diameter. Here, the "fiber diameter" of the present invention refers to covering the multifilaments with an entrapment agent such as epoxy resin, and with respect to the cross-section of the fiber in the direction perpendicular to the fiber axis, 10 or more single filaments can be observed using a scanning electron microscope (SEM). The magnification of the fiber is obtained by taking an image. Randomly select fibers within the same image from each of the captured images, measure the fiber area, and measure the diameter obtained by converting a perfect circle to the first decimal place in μm. A simple number average was taken, and the value rounded to the first decimal place was taken as the fiber diameter (μm). Here, when there is a hollow portion in the fiber cross-section in the direction perpendicular to the fiber axis, the fiber area is also added to the area of the hollow portion.

Furthermore, the width of the opening of the present invention can be obtained by the following method. That is, the multifilaments are covered with an encapsulating agent such as epoxy resin, and the cross-section of the fiber in the direction perpendicular to the fiber axis is taken with a transmission electron microscope (TEM) at a magnification at which more than 10 single-filament fibers can be observed. In the fiber of the obtained image, when there is an opening from the center of the fiber to the surface of the fiber, the image analysis software is used to analyze it, and the line S' ( For example, in the width W' (eg, W' of FIG. 6(b) ) of the opening in the vertical direction S') in FIG. 6(b), the shortest width is calculated in units of μm. The simple number average was calculated|required from the result performed with respect to 10 monofilaments in this way, and the value which rounded off the 2nd decimal place was made into the opening part width. Also, calculate the numerical value obtained by dividing the opening width obtained by each monofilament by the fiber diameter and multiplying it by 100, and then obtain the simple number average of the results obtained by applying this to 10 monofilaments, and round up to the nearest decimal point. The value is referred to as "the ratio (%) of the width of the opening to the fiber diameter" in the present invention.

In the present invention, the width of the opening is preferably 10% or less of the fiber diameter. That is, within this range, it is possible to prevent the hollow portion from collapsing due to inter-fiber engagement or deviation of the opening portion due to an excessively wide opening portion, and to prevent loss of the texture of the lightweight feeling and moderate rebounding feeling.

In addition, the width of the opening is preferably set to be 5% or less of the fiber diameter, so that fibrillation due to fiber abrasion due to the opening can be suppressed, and post-processing such as coating a functional agent can be performed. The functional agent entering the hollow part is prevented from falling off due to washing, etc., and the performance durability of the functional agent can be greatly improved. However, if the width of the opening is too narrow, the water absorption due to the capillary phenomenon of the opening may become weak, and the functional agent may not fully enter the hollow part when the functional agent is applied. The substantial lower limit is 1% of the fiber diameter.

The polymers constituting the flat hollow fibers among the conjugate fibers, hollow fibers, and multifilaments of the present invention are preferable because they are thermoplastic polymers because they are excellent in processability. The polymer group constituting the fiber is preferably a polyester-based, polyethylene-based, polypropylene-based, polystyrene-based, polyamide-based, polycarbonate-based, polymethylmethacrylate-based, polyphenylene sulfide-based isopolymer groups and their copolymers.

In particular, from the viewpoint of imparting high interfacial affinity and obtaining fibers with no abnormality in the composite cross-section, the thermoplastic polymer used in the conjugate fiber, hollow fiber, and flat hollow fiber of the multifilament of the present invention is preferably all are the same group of polymers and their copolymers.

Furthermore, the polymer may also contain inorganic substances such as titanium oxide, silicon dioxide, barium oxide, etc.; colorants such as carbon black, dyes, pigments, etc.; flame retardants, fluorescent whitening agents, antioxidants, or ultraviolet absorbers, etc. various additives. Particularly preferably, the poorly soluble polymer contains 1.0 mass % or more of titanium oxide. In this way, when the easily soluble polymer is dissolved, the titanium oxide precipitated on the surface of the poorly soluble polymer also falls off, and irregularities are formed on the surface, which not only suppresses the increase in reflection caused by light scattering and the light incident angle. (dazzling), make the appearance better, and can also use the titanium oxide inside the fiber to obtain the functions of anti-penetration and ultraviolet shielding.

The readily soluble polymer is preferably melt-formable from polyester and its copolymers, polylactic acid, polyamide, polystyrene and its copolymers, polyethylene, polyvinyl alcohol, etc., and is more easily soluble than other components choice of polymers.

Furthermore, from the viewpoint of simplification of the elution process of the easily soluble polymer, the easily soluble polymer is preferably a copolyester, polylactic acid, or polyvinyl alcohol that exhibits ease of dissolution in an aqueous solvent, hot water, or the like. Wait. In particular, in order to exhibit easy dissolution to aqueous solvents such as alkaline aqueous solutions while maintaining the crystallinity, even if a false twisting process such as wiping is performed under heating, the smoothness of high-level processing such as fusion between conjugate fibers does not occur. In terms of, preferably, the polyester of 5mol%～15mol% of isophthalic acid-5-sodium sulfonate is copolymerized, and in addition to the aforementioned isophthalic acid-5-sodium sulfonate, the weight-average molecular weight is still 500～500～ Polyester of 3000 polyethylene glycol copolymerized in the range of 5 mass % to 15 mass %.

The term "insoluble polymers with different melting points" in the present invention refers to polymers from polyester series, polyethylene series, polypropylene series, polystyrene series, polyamide series, polycarbonate series, and polymethyl methacrylate series. , polyphenylene sulfide series and other melt-molded thermoplastic polymers and their copolymers, polymers with a melting point difference of 10°C or more are combined.

The flat hollow fibers among the conjugate fibers, hollow fibers, and multifilaments of the present invention are intended to take advantage of the difference in shrinkage of poorly soluble polymers having different melting points to exhibit a crimped form. Therefore, as a combination of poorly soluble polymers having different melting points, it is preferable to set one of them as a low-melting polymer with high shrinkage and the other as a high-melting polymer with low shrinkage. In particular, from the viewpoints of preventing peeling and imparting stability to high-level processing and imparting service durability to fabrics, the combination of polymers is more preferably from the main chain such as polyester with ester bonds and polyamide with amide bonds. All bonds present are selected from the same same polymer group.

The combination of the low-melting-point polymer and the high-melting-point polymer in the same polymer group, as a polyester system, for example: copolymerized polyethylene terephthalate/polyethylene terephthalate, Polybutylene terephthalate/polyethylene terephthalate, polytrimethylene terephthalate/polyethylene terephthalate, thermoplastic polyurethane/polyethylene terephthalate Diester, polyester-based elastomer/polyethylene terephthalate, polyester-based elastomer/polybutylene terephthalate, examples of polyamide-based systems include nylon 66/nylon 610, nylon 6-nylon 66 copolymer/nylon 6 or 610, PEG copolymerized nylon 6/nylon 6 or 610, thermoplastic polyurethane/nylon 6 or 610, as polyolefins, for example: ethylene-propylene rubber microfiber Various combinations of dispersed polypropylene/polypropylene, propylene-alpha olefin copolymer/polypropylene, etc. are available.

Among these, from the viewpoint of suppressing the collapse of the hollow portion inside the fiber due to high flexural rigidity and obtaining good color development during dyeing, the poorly soluble polymers having different melting points are preferably a combination of polyesters .

In addition, the copolymerization component system of copolymerized polyethylene terephthalate includes, for example, succinic acid, adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, cis-butane Oleic acid, phthalic acid, isophthalic acid, isophthalic acid-5-sodium sulfonate, etc., but from the viewpoint of maximizing the shrinkage difference with polyethylene terephthalate, it is preferable to use Polyethylene terephthalate in which isophthalic acid is copolymerized at 5-15 mol%.

Furthermore, since environmental problems have attracted attention, from the viewpoint of reducing the environmental load, the present invention is also suitable for the use of plant-derived biopolymers or regenerated polymers. Recycled polymers that are recycled by any method such as property recovery, material recovery, and thermal recycling.

In the case of using a biopolymer or a regenerated polymer, the polymer properties of the polyester-based resin are such that the characteristics of the present invention can be distinguished, as described above, the collapse of the hollow portion inside the fiber due to the high bending rigidity can be suppressed, and the dyeing can be performed. Good color development is obtained. From these viewpoints, recycled polyester is preferably used in the present invention.

In the flat hollow fiber of the composite fiber, hollow fiber and multifilament of the present invention, the area ratio of the insoluble polymer on the low melting point side to the insoluble polymer belonging to the high melting point polymer is preferably low melting point/high melting point In the range of 70/30~30/70. If it is within this range, it will not be affected by pore plugs and texture hardening caused by the high shrinkage of the low-melting polymer due to heat treatment, and the crimped form caused by the difference in shrinkage can be fully manifested, and a coarser interfiber space can be obtained. .

The flat hollow fibers among the conjugate fibers, hollow fibers, and multifilaments of the present invention preferably have a fiber diameter of 20 μm or less from the viewpoint of making the texture softer. Within this range, in addition to flexibility, a sufficient sense of rebound can be obtained, which is a range suitable for clothing applications such as trousers and shirts that require a texture with elastic resilience.

In addition, the fiber diameter is preferably 15 μm or less. Accordingly, the fiber bundles or the fabrics composed of the fiber bundles are more flexible, and are suitable for use in clothing such as linings and blouses that come into contact with the skin. However, when the fiber diameter is less than 8 μm, since the fiber diameter is too small, a portion where the bending recovery property is lowered may occur, or the color developing property may also be lowered. Therefore, the fiber diameter of the fibers of the present invention is preferably 8 μm or more.

Furthermore, at least a part of the fiber product of the present invention containing the conjugate fiber, hollow fiber, and multifilament of the present invention, when used as a fiber product, voids and concavities and convexities are generated between adjacent fibers in the longitudinal direction of the cross-section at the aligned and unaligned positions. The difference between the fibers can form complex voids and concavities and convexities between the fibers, which can present a specific refreshing touch. In addition, by providing a hollow portion inside the fiber, it is possible to obtain a textile material excellent in wearing comfort that also achieves a moderate rebound feeling and a soft texture with a bulky feeling by cooperating with the complex voids or unevenness between the fibers.

Therefore, the conjugated fibers, hollow fibers and multifilaments of the present invention can be applied to general clothing such as jackets, skirts, trousers, underwear, etc., as well as sports clothing and clothing materials, and can also be used in interiors such as carpets and sofas by taking advantage of their comfort. Products; vehicle interior parts such as car seats; and various fiber products for daily use such as cosmetics, cosmetic masks, and health products.

An example of the manufacturing method of the conjugated fiber, hollow fiber, and multifilament of the present invention will be described in detail below.

The method for producing the conjugate fiber, hollow fiber, and multifilament of the present invention includes, for example, a melt spinning method for the purpose of producing long fibers, a solution spinning method such as a wet method and a wet-dry method, and a method capable of obtaining a sheet-like fiber structure. Melt blowing, spunbonding, and the like are preferably melt spinning from the viewpoint of improving productivity.

Furthermore, in the case of the melt spinning method, it can be produced by using a composite spinning nozzle to be described later. The spinning temperature at this time is preferably set to be a high melting point or high viscosity polymer that exhibits fluidity among the types of polymers used. temperature. The temperature at which the fluidity is exhibited varies depending on the molecular weight, but if it is set between the melting point of the polymer and the melting point +60°C, stable production can be achieved.

The spinning speed is preferably about 500 to 6000 m/min, and can be changed according to the physical properties of the polymer and the purpose of use of the fiber. In particular, from the viewpoint of forming a high orientation and improving the mechanical properties, it is preferable to set it to 500 to 4000 m/min, and then by stretching, the uniaxial orientation of the fibers can be promoted, so it is preferable. At the time of stretching, it is preferable to appropriately set the preheating temperature with the softenable temperature such as the glass transition temperature of the polymer as an index. The upper limit of the preheating temperature is preferably set to a temperature that does not cause disorder of the guide wire path due to self-elongation of the fiber during the preheating process. For example, in the case of PET (polyethylene terephthalate) having a glass transition temperature in the vicinity of 70°C, the preheating temperature is usually about 80 to 95°C.

Furthermore, the conjugate fiber, hollow fiber and multifilament of the present invention can be produced stably if the discharge rate per single hole of the spinning nozzle is about 0.1 to 10 g/min per hole. After the discharged polymer flow is cooled and solidified, an oil agent is applied, and it is pulled by a roller having a predetermined peripheral speed. Then, it is stretched with a heating roll to obtain desired conjugate fibers, hollow fibers, and multifilaments.

Furthermore, in the conjugate fiber of the present invention composed of two or more kinds of polymers, by setting the melt viscosity ratio of the polymers used to be less than 5.0 and the difference in solubility parameter value to be less than 2.0, the composite fiber can be stably formed. The polymer flow is preferred because it can obtain fibers with a good composite cross-section.

When producing the conjugate fiber of the present invention composed of two or more kinds of polymers, it is preferable to use the conjugate spinning nozzle described in, for example, Japanese Patent Laid-Open No. 2011-208313.

The composite spinning nozzle shown in FIG. 12 of the present invention is assembled in a spin pack in a state in which roughly three components, such as a metering plate 1, a distribution plate 2, and a discharge plate 3, are stacked from the top, and then used for spinning. Incidentally, FIG. 12 shows an example in which three types of polymers, namely, A polymer, B polymer, and C polymer, are used. It is difficult to compound three or more kinds of polymers in a conventional compound spinning nozzle, and it is preferable to use a compound spinning nozzle using a fine flow path as illustrated in FIG. 12 .

In the spinning nozzle member illustrated in FIG. 12 , the amount of polymer per hole in each discharge hole and the amount of polymer per hole in each distribution hole are measured by the measuring plate 1 . The measured polymer flow is arranged into a composite cross-section of single fibers by the distribution plate 2 , and the composite polymer flow formed by the distribution plate 2 is compressed and discharged by the discharge plate 3 .

In order to avoid the complicated description of the composite spinning nozzle, although not shown in the figure, the components layered above the metering plate 1 can be used as long as the components that form the flow path are used in conjunction with the spinning machine and the spinneret assembly. By designing the metering plate 1 in accordance with the existing flow path components, the existing spinneret assembly and its components can be directly applied.

Therefore, it is not necessary to specialize the spinning machine especially for the spinning nozzle. In fact, a plurality of flow path plates may be laminated between the flow path and the measuring plate or between the measuring plate 1 and the distribution plate 2 . The purpose of this is to provide a configuration in which a flow path capable of efficiently transferring the polymer is provided in the cross-sectional direction of the spinning nozzle and the cross-sectional direction of the single fiber, and is introduced into the distribution plate 2 . The composite polymer stream discharged from the discharge plate 3 is cooled and solidified in accordance with the above-mentioned production method, and then an oil is applied, and then pulled by a roller having a predetermined peripheral speed. Then, it is extended|stretched by heating rolls, and becomes a desired conjugated fiber.

In order to elute the easily soluble polymer in the innermost layer from the conjugate fiber of the present invention and obtain a hollow fiber composed only of the poorly soluble polymer, it is only necessary to immerse the conjugate fiber in a solvent or the like that can dissolve the easily soluble polymer. , remove the easily soluble polymer. When the easily soluble polymer is copolymerized polyethylene terephthalate or polylactic acid, such as sodium isophthalate-5-sulfonate or polyethylene glycol, etc., an aqueous sodium hydroxide solution can be used. Equal alkaline solution.

In the method of treating the conjugate fiber of the present invention with an alkaline aqueous solution, for example, after a fiber structure composed of the conjugate fiber is prepared, it may be immersed in the alkaline aqueous solution. At this time, it is preferable to heat the alkaline aqueous solution to 50° C. or higher, since the hydrolysis can be accelerated. Moreover, if a fluid dyeing machine etc. are used, since a large amount can be processed at one time, it is preferable from an industrial point of view. [Example]

Hereinafter, the conjugate fibers and hollow fibers of the present invention will be specifically described by way of examples.

The following evaluation was performed about the Example and the comparative example. A. Melt viscosity of polymer Fragmented polymer was made into a water content of 200 ppm or less by a vacuum dryer, and the melt viscosity was measured by changing the strain rate stepwise by a capillary rheometer by Toyo Seiki Seiki Co., Ltd. In addition, the measurement temperature is the same as the spinning temperature, and the time from the time the sample was put into the heating furnace to the start of the measurement under nitrogen atmosphere was set to 5 minutes, and the value at the shear rate of 1216 s ⁻¹ was set to the melting of the polymer. viscosity and evaluated.

B. Melting point of polymer The fragmented polymer was made to have a moisture content of 200 ppm or less in a vacuum dryer, and weighed about 5 mg. Using a differential scanning calorimeter (DSC) Q2000 model manufactured by TA Instruments, the temperature was increased from 0 °C to 300 °C at a heating rate of 16 °C/min. DSC measurement was performed after holding at 300°C for 5 minutes. Melting points were calculated from the melting peaks observed during the ramp-up. The measurement system was performed three times per sample, and the average value was taken as the melting point. In addition, when a plurality of melting peaks were observed, the melting peak top on the highest temperature side was taken as the melting point.

C. Fineness The weight of 100 m of fibers was measured, and a value 100 times the value was calculated. This operation is repeated 10 times, and the value rounded to the second decimal place of the average value is set as the fineness (dtex).

D. Section parameters of composite fibers (RB/RA) The composite fibers are encapsulated with an encapsulating agent such as epoxy resin, and the cross-section of the fibers in the direction perpendicular to the fiber axis is obtained by photographing an image with a scanning electron microscope (SEM) manufactured by HITACHI at a magnification at which more than 10 filaments can be observed. Fibers were randomly selected in the same image from each of the captured images, and analyzed using WinROOF, a computer software made by Mitani Shoji. The fibers were incised at at least 2 points (such as a1 and a2 in Fig. 2(a)) on the surface of the fiber, and only In the range where the circumference of the inscribed circle existing inside the fiber does not intersect the fiber surface, the diameter of the circle having the largest diameter (for example, A in FIG. 2( a )) is calculated. The simple number average was calculated|required from the result performed with respect to 10 monofilaments in this way, and the value rounded to the nearest decimal point was made into the inscribed circle diameter RA.

Furthermore, in the range where the circumference of the circumscribed circle that is circumscribed on the fiber surface at at least two points (for example, b1 and b2 in Fig. 2(a)) and exists only outside the fiber does not intersect the fiber surface, it is calculated that the The diameter of the circle with the smallest diameter (for example, B in Fig. 2(a) ) is obtained by calculating a simple number average from the results of the 10 monofilaments, and the value rounded to the nearest decimal point is used as the circumscribed circle diameter RB. The quotient obtained by dividing RB obtained from each fiber by RA was calculated, and a simple number average was obtained from the results obtained by applying this to 10 monofilaments, and the value rounded to the second decimal place was set as RB/RA.

E. Fiber diameter The composite fibers and multifilaments are covered with entrapment agents such as epoxy resin, and the cross-section of the fiber in the direction perpendicular to the fiber axis is obtained by using a scanning electron microscope (SEM) at a magnification that can observe more than 10 single fibers. . Randomly select fibers within the same image from each of the captured images, measure the area, measure the diameter obtained by converting a perfect circle in μm to the first decimal place, and obtain the simple result from the results of 10 monofilaments. The number was averaged, and the value rounded to the first decimal place was used as the fiber diameter (μm). Here, when there is a hollow portion in the fiber cross-section perpendicular to the fiber axis, the fiber area is also added to the area of the hollow portion.

F. Connected width The composite fibers are covered with an entrapment agent such as epoxy resin, and the cross section of the fiber in the direction perpendicular to the fiber axis is photographed with a transmission electron microscope (TEM) at a magnification that can observe more than 10 fibers. In the composite fiber of the obtained image, when the easily soluble polymer is connected from the fiber center to the fiber surface, it is analyzed using WinROOF made by Mitani Shoji, a computer software. The shortest width is calculated in units of μm in the connecting portion width W (eg, W in FIG. 3( c )) in which the straight line S (eg, S in FIG. 3( c )) is in the vertical direction. A simple number average was obtained from the results performed on 10 monofilaments in this manner, and the value rounded to the second decimal place was defined as the connection width. In addition, divide the segment width obtained from each monofilament by the fiber diameter, and multiply the value by 100 to calculate the value obtained by multiplying by 100. From the result of applying this to 10 monofilaments, a simple number average is obtained, and the number is rounded up to the decimal point. The value of is the ratio (%) of the connection width to the fiber diameter.

G. Flatness The multifilaments are covered with an entrapment agent such as epoxy resin, and the cross-section of the fiber in the direction perpendicular to the fiber axis is obtained by photographing an image with a scanning electron microscope (SEM) manufactured by HITACHI at a magnification at which more than 10 single filaments can be observed. Fibers are randomly selected in the same image from each of the captured images and analyzed using image analysis software. As shown in Figure 5(a), a straight line connecting the two points (c1, c2) that are farthest apart from any point on the periphery of the fiber (c1-c2) was set as the major axis, and a straight line (d1-d2) passing through the midpoint of the major axis and orthogonal to the major axis was set as the minor axis, and a value obtained by dividing the major axis length by the minor axis length was calculated. The simple number average was calculated|required from the result performed with respect to 10 fibers in this way, and the value which rounded off the 2nd decimal place was made into flatness.

H. Hollow ratio The multifilaments are covered with an entrapment agent such as epoxy resin, and the cross-section of the fiber in the direction perpendicular to the fiber axis is obtained by photographing an image with a scanning electron microscope (SEM) manufactured by HITACHI at a magnification at which more than 10 single filaments can be observed. When fibers randomly selected in the same image from each of the captured images have a hollow portion, use image analysis software to analyze and obtain the area obtained from the outer shape including the fiber hollow portion and the area of the hollow portion, respectively. The portion area was divided by the area obtained from the outer shape including the fiber hollow portion, and the value multiplied by 100 was calculated. The simple number average was calculated|required from the result performed with respect to 10 fibers in this way, and the value rounded to the 1st decimal place was made into the hollow ratio (%).

I. Opening width The multifilaments are covered with an entrapment agent such as epoxy resin, and the cross-section of the fiber in the direction perpendicular to the fiber axis is taken with a transmission electron microscope (TEM) at a magnification that can observe more than 10 fibers. When the fiber in the obtained image has an opening from the center of the fiber to the surface of the fiber, the image analysis software is used to analyze it, so that it is relative to the straight line S' that passes through the center G of the fiber and is parallel to the opening (for example, Fig. 6 ). (b) S') of the width W' of the opening in the vertical direction (for example, W' in FIG. 6(b) ), the shortest width is calculated in units of μm. The simple number average was calculated|required from the result performed with respect to 10 monofilaments in this way, and the value which rounded off the 2nd decimal place was made into the opening part width. In addition, the opening width obtained from each filament was divided by the fiber diameter, and the value multiplied by 100 was calculated, and the simple number average was obtained from the result of applying this to 10 filaments, and the value was rounded up to the decimal point. Let it be the ratio of the opening width to the fiber diameter (the opening ratio) (%).

J. Number of crimped teeth (tooth/cm) For fabrics composed of multifilaments, the multifilaments are extracted from the fabrics in a manner that does not cause plastic deformation, and the single ends of the multifilaments are fixed. A load of 1 mg/dtex was applied to the other end, and after 30 seconds or more, a mark was made at any point where the distance between the two points in the fiber axis direction of the multifilament became 1 cm. Then, the fibers were separated from the multifilaments so that plastic deformation would not occur, and the distance between the marks marked in advance was adjusted to the original 1 cm state, and the fibers were fixed on the carrier glass. An image of this sample was taken with a digital microscope at a magnification that enables observation of a 1 cm mark. In the photographed image, when the multifilament has a twisted crimp shape of the fiber as shown in Fig. 11, the number of crimps existing between the marks is obtained. This operation was performed for 10 fibers made of the same polymer, and a simple number average was obtained from the results, and the numerical value rounded to the first decimal place was set as the number of crimping teeth (teeth/cm).

K. Variation coefficient CV of the rotation angle of the long axis In the fabric composed of multifilaments, the cross section of the fabric perpendicular to the longitudinal direction of the fabric and perpendicular to the axis direction of the multifilament fibers is imaged with a scanning electron microscope (SEM) manufactured by HITACHI at a magnification at which more than 20 fibers can be observed. Among the fibers in the obtained image, when the fiber has a flat cross-section, the image analysis software is used to analyze it, and as shown in Fig. 5(b), the two points (c1, c2) that are farthest from any point on the fiber periphery are connected. The straight line (c1-c2) is set as the long axis, and the straight line passing through the midpoint of the long axis of the flat hollow fiber and parallel to the bottom of the captured image is rotated counterclockwise around the midpoint of the long axis, and the evaluation of the long axis and the straight line slope are consistent. Rotation angle (θ). This evaluation was performed on 20 fibers randomly selected from the multifilaments, and the standard deviation and average value of the results were calculated. The standard deviation was divided by the mean value, and the value multiplied by 100 was calculated, and the value rounded to the first decimal place was used as the coefficient of variation CV (%) of the rotation angle of the major axis.

L. Texture evaluation (lightness, softness, rebound, smoothness, roughness) Adjust the fiber count so that the coverage factor (CFA) in the warp direction becomes 800 and the coverage factor (CFB) in the weft direction becomes 1200. Count to make 3/1 twill. Among them, the so-called "CFA" and "CFB" here refer to the measurement of the warp density and weft density of the fabric according to JIS-L-1096: 2010 8.6.1, according to the 2.54cm interval, from CFA = warp density × (warp yarn fineness) ^{1 /2} , CFB=Weft density×(Weft fineness) ^1/2 The value obtained by the formula. The obtained fabric was subjected to scouring, wet heat treatment, alkali treatment, and heat setting, and then five textures including lightness, softness, rebound, smoothness, and roughness were evaluated using the following methods.

The feeling of lightness was evaluated by the following method. That is, the thickness (cm) of a 20cm×20cm fabric was measured under a certain pressure (0.7kPa) using a standard load thickness gauge (PG-14J) manufactured by TECLOCK, and after the fabric volume was calculated, the fabric weight (g) was divided by The quotient of the obtained volume is set as the apparent density (g/cm ³ ) of the fabric. From the obtained apparent densities, the feeling of lightness was determined in three stages according to the following criteria.

◎: Excellent in light weight (apparent density≦0.34) ○: Lightweight feeling is good (0.34＜apparent density≦0.44) ×: Poor lightweight feel (0.44 < apparent density)

The flexibility was evaluated by the following method using a pure bending tester (KES-FB2) manufactured by KATO TECH. That is, a fabric of 20 cm×20 cm is grasped according to the effective sample length of 20 cm×1 cm, and is bent under the condition of maximum curvature ±2.5 cm ⁻¹ in the direction of the weft. Calculate the quotient obtained by dividing the difference in bending moment (gf·cm/cm) per unit width between the curvatures of 0.5cm ^-1 and 1.5cm ^-1 at this time by the difference in curvature of 1cm ^-1 , and the curvature of -0.5cm ^-1 The average value of the quotient of the difference in bending moment per unit width (gf·cm/cm) from -1.5 cm ^-1 divided by the difference in curvature of 1 cm ^-1 . This action is performed 3 times for each point, and a total of 10 points are performed. The simple number average of the results is obtained, and the quotient of the 4th decimal point is rounded off and divided by 100 as the bending hardness B×10 ^-2 (gf・cm ² /cm). From the obtained bending hardness B×10 ⁻² , the flexibility was determined in three stages according to the following criteria, respectively.

◎: Excellent flexibility (flexural hardness B×10 ^-2 ≦1.0) ○: Good flexibility (1.0＜flexural hardness B×10 ^-2 ≦2.0) ×: Poor flexibility (2.0＜flexural hardness B×10 ^-2 )

The rebound feeling was evaluated by the following method. That is, using a pure bending tester (KES ^- FB2) manufactured by KATO TECH, hold a 20cm×20cm fabric according to the effective sample length of 20cm×1cm, and calculate the hysteresis width ( gf・cm/cm). This action is performed 3 times per one place, and a total of 10 actions are performed, the simple number average of the results is obtained, and the quotient obtained by rounding off the fourth decimal place and dividing by 100 is set as the bending recovery 2HB× ^10-2 (gf・cm/cm). From the obtained bending recovery 2HB×10 ⁻² , the rebound feeling was determined in three stages according to the following criteria, respectively.

◎: Excellent rebound feeling (bending recovery 2HB×10 ^-2 ≦1.0) ○: Good rebound feeling (1.0＜bending recovery 2HB×10 ^-2 ≦2.0) ×: Poor rebound feeling (2.0＜bending recovery 2HB×10 ^-2 )

The smoothness and roughness were evaluated according to the following methods. That is, using an automatic surface tester (KES-FB4) manufactured by KATO TECH, a load of 50 g was applied to a 1 cm × 1 cm terminal formed by winding a 10 cm × 10 cm area of a 20 cm × 20 cm fabric with a piano wire, and the slid at a rate of 1.0 mm/sec. , obtain the average friction coefficient MIU and the variation MMD of the average friction coefficient. This action is performed 3 times at each location, for a total of 10 performed. For the results, the average friction coefficient MIU was calculated as a simple number average, and the value rounded to the second decimal place was used as the friction coefficient. From the obtained friction coefficient, the smoothness was determined in three stages according to the following criteria.

◎: Excellent smoothness (coefficient of friction < 0.5) ○: Good smoothness (0.5≦Coefficient of friction＜1.0) ×: Poor smoothness (1.0≦friction coefficient)

In addition, the variation MMD system of the average friction coefficient was calculated|required as a simple number average, and the value rounded to the 4th decimal place was set as friction variation. From the obtained friction variation, roughness was judged in three stages according to the following criteria.

◎: Excellent roughness (0.9≦ friction variation) ○: Good roughness (0.5≦Coefficient of friction＜0.9) ×: Poor roughness (coefficient of friction < 0.5)

M. Functional Evaluation (Water Absorption, Fast Drying, Stretchability) The fiber count was adjusted so that the coverage factor (CFA) in the warp direction was 800 and the coverage factor (CFB) in the weft direction was 1200 to prepare a 3/1 twill fabric. Among them, the so-called "CFA" and "CFB" here refer to the measurement of the warp density and weft density of the fabric according to JIS-L-1096: 2010 8.6.1, according to the 2.54cm interval, from CFA = warp density × (warp yarn fineness) ^{1 /2} , CFB=Weft density×(Weft fineness) ^1/2 The value obtained by the formula. The obtained fabric was subjected to scouring, wet heat treatment, alkali treatment, and heat setting, and then the following methods were used to evaluate two functions, such as water absorption, quick-drying, and stretchability.

The water absorption quick-drying property was evaluated by the following method. That is, after dripping 0.1 cc of water on a 10cm×10cm fabric, in an environment of temperature 20°C and relative humidity 65RH%, the fabric weight is measured every 5 minutes, and the time (minutes) when the residual moisture content becomes 1.0% or less is obtained. This operation was performed for a total of 3 places, the simple number average of the results was obtained, and the value rounded to the nearest decimal point was set as the water diffusion time (minutes). From the obtained water diffusion time, the water absorption and quick-drying properties were determined in three stages according to the following criteria.

◎: Excellent water absorption and quick drying (water diffusion time ≦20) ○: Good water absorption and quick drying (20＜water diffusion time≦40) ×: Poor water absorption and quick drying (40＜water diffusion time)

The stretchability was evaluated by the following method. That is, it implemented according to the elongation ratio A method (constant-rate extension method) described in the item 8.16.1 of JIS L1096:2010. In addition, when using the load of 17.6N (1.8kg) by the strip method, the test conditions were set as the sample width 5cm x length 20cm, the clamp interval 10cm, and the tensile speed 20cm/min. In addition, the initial load is based on the method of JIS L1096:2010, and the weight corresponding to the sample width of 1 m is used. This test was performed three times in the weft direction of the fabric, the simple numerical average of the results was obtained, and the value rounded to the nearest decimal point was set as the fabric elongation (%). From the obtained fabric elongation, the stretchability was determined in three stages according to the following criteria.

◎: Excellent stretchability (15≦elongation) ○: Good stretchability (5≦elongation <15) ×: Poor stretchability (elongation <5)

N. Wear resistance A plain woven fabric was produced by adjusting the fiber count in such a manner that the cover factor (CFA) in the warp direction was 1100 and the cover factor (CFB) in the weft direction was 1100. The obtained fabric was dyed black using the disperse dye Sumikaron Black S-3B (10% owf). The dyed fabric was cut into a circle with a diameter of 10 cm, which was wetted with distilled water and then mounted on the disc. Then, the fabric cut into a 30cm square is fixed on a horizontal plate according to the dry state.

Make the disc with the fabric moistened with distilled water in contact with the fabric fixed on the horizontal plate horizontally, and make the disc move circularly for 10 minutes according to the load of 420g and the speed of 50rpm in the way that the center of the disc draws a circle with a diameter of 10cm. , rub the 2 pieces of fabric together. After rubbing, leave it for 4 hours. For the degree of discoloration and fading of the fabric installed on the disc, use the gray scale of discoloration, and implement a series judgment of 1 to 5 according to the 0.5-level scale. From the result of the obtained stage number determination, the abrasion resistance was determined in three stages according to the following criteria.

◎: Excellent in abrasion resistance (level judgment: 4 or more) ○: Good abrasion resistance (series judgment: 3 or 3.5) ×: Poor wear resistance (judgment of the number of stages: less than 3)

[Example 1] Polyethylene terephthalate (SSIA-PEG copolymerized PET, melt viscosity: 100Pa·s, melting point: 233℃). As the polymer 2, polyethylene terephthalate (IPA copolymerized PET, melt viscosity: 140 Pa·s, melting point: 232° C.) was prepared by copolymerizing 7 mol % of isophthalic acid. Polyethylene terephthalate (PET, melt viscosity: 130 Pa·s, melting point: 254° C.) was prepared as polymer 3 series.

After the polymers were melted at 290°C, the polymer 1/polymer 2/polymer 3 were measured in a weight ratio of 20/40/40, and then flowed into the spray nozzle assembled with the composite spinning nozzle shown in Figure 5. in the wire assembly. As shown in Fig. 3(a), the polymer 1 is arranged in the innermost layer and the connecting part from the center of the fiber to the fiber surface, and the outermost layer is composed of the polymer 2 and the polymer 3. In the side-by-side composite structure, the inflowing polymer is discharged from the discharge hole.

After cooling and solidifying the spouted composite polymer stream, an oil agent is given, and it is coiled at a spinning speed of 1500 m/min, and then stretched between rollers heated to 90°C and 130°C to produce 56dtex-36 pieces (fiber diameter). 12 μm) composite fibers.

The ratio RB/RA of the inscribed circle diameter RA to the circumscribed circle diameter RB of the obtained composite fiber was 1.8. In addition, the communication width was 0.5 μm, and the ratio was 4% with respect to the fiber diameter of 12 μm, and it was confirmed that it belongs to the conjugate fiber of the present invention.

The obtained conjugated fibers were woven, subjected to 80°C scouring treatment and 130°C wet heat treatment, and then treated in a 1 mass % sodium hydroxide aqueous solution (bath ratio 1:50) heated to 90°C, which is easily soluble polymerization. More than 99% of polymer 1 was removed. At this time, since there is a connecting portion from the center of the fiber to the surface of the fiber, the polymer 1 in the innermost layer is rapidly eluted within 10 minutes after the start of the elution treatment.

Then, heat-setting was performed at 180° C., as shown in FIG. 2( b ), a multifilament formed by a flat hollow fiber with a flatness of 1.8, a hollow ratio of 18%, and a crimp number of 17 teeth/cm was obtained. fabric. Moreover, this flat hollow fiber system has an opening part, and the opening part width is 0.5 micrometer, and the ratio with respect to the fiber diameter is 4%.

The coefficient of variation CV of the rotation angle of the long axis of the flat hollow fibers in the fabric-based multifilament composed of this multifilament was 27%. Therefore, the surface of the textile material is uneven due to the inconsistency of the long axis direction of the cross section. As a result, a smooth feeling (friction coefficient: 0.3) was obtained when contacting the cloth surface, and a refreshing touch due to a large rough feeling (friction variation: 0.9×10 ⁻² ) was felt. In addition, the fabric has complex voids between fibers, and cooperates with the hollow part inside the fibers, and has a moderate rebound feeling (bending recovery 2HB: 0.9 × 10 ^-2 gf·cm/cm), and a bulky feeling (appearance Density: 0.33 g/cm ³ ) soft texture (flexural hardness B: 0.9×10 ⁻² gf·cm ² /cm). In addition, this fabric system has excellent stretchability (fabric elongation: 16%) and water absorption and quick-drying (water diffusion time: 25 minutes) due to the presence of openings, and has a texture that is directly related to the feeling of wearing on the human body. A fabric with excellent wearing comfort and function.

Furthermore, due to the narrow opening of the fabric, not only the voids inside the fibers can be kept from collapsing after the fabric is processed, but also the functional agent entering the hollow part when the functional agent is applied will not fall off due to washing, etc., which can greatly improve the performance of the functional agent. Performance Durability. In addition, it was found that this fabric also has good abrasion resistance (white spot test: grade 4) that does not cause discoloration and discoloration due to fibrillation by the openings. The results are shown in the following table.

[Example 2, 3] Example 1 was carried out except that the cross-sectional shape was changed to a multi-lobed shape (Example 2) as shown in FIG. 3( b ) and a flat multi-lobed shape (Example 3) of FIG.

In Example 2, by forming unevenness on the fiber surface, light diffuse reflection can be used to suppress uneven gloss (dazzle) of the fabric, and the water absorption and quick-drying property can be improved by using fine inter-fiber spaces.

Example 3 is a flat and multi-lobed shape, the complex inter-fiber gaps generated by the flat and twisted, and the micro-fiber gaps of the uneven fiber surface caused by the multi-lobed shape cooperate with each other, which can further improve the light weight. Texture such as volume and rebound, and functions such as water absorption and quick drying. The results are shown in the following table.

[Example 4] As shown in FIG. 3( d ), the composite structure was carried out in accordance with Example 1, except that the structure in which the easily soluble polymer was present in the outermost layer was changed.

Example 4 is the effect of removing the inter-fiber voids generated when the soluble polymer in the outermost layer is removed, so that the fibers fixed at the bundle point of the woven fabric can be moved, thereby improving the flexibility, and reducing the high void ratio. The apparent density increases the sense of lightness. The results are shown in the following table.

[Example 5, 6] Except for changing the ratio RB/RA (variability) of the fiber inscribed circle diameter RA to the circumscribed circle diameter RB to RB/RA=1.3 (Example 5), RB/RA=1.0 in FIG. 1(c) (Example 6), the rest are implemented according to Example 1.

In Examples 5 and 6, as the degree of variation became smaller, the three-dimensional barrier effect during twisting became smaller, and the roughness was reduced. On the other hand, the crimped shape exhibited by the heat treatment became fine and close to the coil shape. Therefore, it can not only increase the stretchability, but also increase the fine inter-fiber space to improve the softness. The results are shown in the following table.

[Example 7] Except that the cross-sectional shape of the conjugate fiber is changed to a cross-section in which the joint surface and the connecting portion of the polymers with different melting points are located on a straight line, and the direction (angle) of the straight line is random (the four types in FIG. 10 are examples of the cross-sectional shape). , and the rest are implemented in accordance with Example 1.

In Example 7, the difference in the distance between the centers of gravity, the crimping shape presented by the heat treatment is different for each single fiber, and the coefficient of variation CV of the rotation angle of the long axis is also improved, not only because of the increased roughness and refreshing touch. Obviously, and by increasing the space between fibers, the feeling of lightness can also be improved. The results are shown in the following table.

[Comparative Example 1] Except that the polymer 2 was changed to the same PET as the polymer 3, the rest were carried out according to Example 1.

In Comparative Example 1, although a certain lightness can be obtained by utilizing the hollow portion inside the fiber, since it does not show a crimped shape, the surface of the textile material has no unevenness and lacks a rough feeling, and because there is no space between fibers, so Lack of softness and rebound. In addition, it does not have functions such as water absorption, quick-drying, and stretchability. The results are shown in the following table.

[Comparative Example 2] After stretching, except between rolls with a processing speed of 250 m/min and a stretching ratio of 1.05 times, while heating with a heater set at 180°C, a friction disc was used to make false twists 3000T/m. Except for the twisting process, all the others were carried out in accordance with Comparative Example 1.

In Comparative Example 2, although a crimped form was obtained by false twisting, the unevenness on the surface of the textile material was monotonous and lacked roughness. The results are shown in the following table.

[Comparative Example 3] Example 1 was carried out except that the composite structure was changed to a structure in which insoluble polymers having different melting points were layered from the center of the fiber toward the surface of the fiber as shown in FIG. 4( b ).

In Comparative Example 2, by removing the easily soluble polymer in the innermost layer to form voids inside the fiber, a certain lightness can be obtained, but because the poorly soluble polymer with different melting points does not exist in a concentrated manner, it is caused by heat treatment. The crimped shape of the product is almost not exhibited, so it lacks flexibility, rebound feeling, rough feeling, and also does not have functions such as water absorption, quick-drying, and stretchability. The results are shown in the following table.

[Comparative Example 4] Polyethylene terephthalate (IPA copolymerized PET, melt viscosity: 140 Pa·s, melting point: 232°C) prepared by copolymerizing 7 mol% of isophthalic acid was prepared as polymer 2 series, and polymer 3 series was prepared as polymer series. Ethylene terephthalate (PET, melt viscosity: 130 Pa·s, melting point: 254°C).

After the polymers were melted at 290°C, the polymer 2/polymer 3 were measured in a weight ratio of 50/50, and then the hollow composite fibers were formed as shown in Figure 4(a), with a hollow ratio of 20%. , the polymer 2 and the polymer 3 are joined to form a side-by-side composite structure, and the inflowing polymer is discharged from the discharge hole.

The spouted composite polymer is cooled and solidified, and then given an oil agent, coiled at a spinning speed of 1500m/min, and then stretched between rollers heated to 90°C and 130°C to produce 56dtex-36 pieces (fiber diameter 13μm) of composite fibers.

The obtained conjugated fibers were woven, subjected to 80°C scouring treatment and 130°C moist heat treatment, and then heat-set at 180°C to obtain a fabric composed of the above conjugated fibers.

In Comparative Example 4, since the fiber had a hollow inside the fiber when it was produced, the hollow collapsed during the weaving process or when crimped by heat treatment, and when it was made into a fabric, it not only lost the lightness, but also lacked flexibility and rebound. feel. The results are shown in the following table.

[Example 8, 9] It carried out according to Example 1 except having changed the connection width by the easily soluble polymer to 8% (Example 8) and 16% (Example 9) with respect to the fiber diameter.

Examples 8 and 9 are poor, and the larger the opening formed after removing the easily soluble polymer, not only the friction coefficient increases due to the opening of the finger when touching with the hand, but also the surface area of the fiber that contacts the water droplet when the water droplet is dropped also increases. , so the water absorption and quick-drying properties are also improved. The results are shown in the following table.

[Example 10, 11] Example 1 was followed except that the weight ratio of polymer 2/polymer 3 was changed to 60/20 (Example 10) and 20/60 (Example 11).

In Examples 10 and 11, the higher the ratio of the polymer 2 belonging to the high shrinkage side, the stronger the crimped state is, and the lightness of the obtained fabric also increases. In addition, the more the polymer 3 belonging to the low shrinkage component, the more excellent the flexibility is, the better the flexibility is, the more pore clogging due to the high shrinkage rate on the high shrinkage side due to heat setting can be suppressed. The results are shown in the following table.

[Example 12, 13] Except for changing the weight ratio of polymer 1/polymer 2/polymer 3 to 10/45/45 (Example 12) and 30/35/35 (Example 13), the rest were carried out in accordance with Example 1.

In Examples 12 and 13, when the weight ratio of the polymer 3 was reduced and the hollow ratio was reduced, the bending hardness was increased, so that a touch with characteristic elasticity was obtained. In addition, when the weight ratio of the polymer 3 is increased and the hollow ratio is increased, the air contained in the fiber increases, which not only increases the lightweight feeling, but also has excellent flexibility and resilience. The results are shown in the following table.

[Example 14, 15] Example 1 was carried out except that the discharge amount was changed so that the fiber diameter was 17 μm (Example 14) and 24 μm (Example 15).

In Examples 14 and 15, by increasing the fiber diameter, the ring of the crimped shape exhibited by the heat treatment became larger, the roughness and lightness were improved, and the bending hardness was also increased, so that a touch with characteristic elasticity was obtained. feel. The results are shown in the following table.

[Example 16] The same procedure as in Example 1 was carried out except that the polymer 3 was changed to polyethylene terephthalate containing 5.0 mass % of titanium oxide (TiO ₂ contains PET).

In Example 16, when the easily soluble polymer was removed, the titanium oxide precipitated on the surface of the polymer 3 also fell off, and unevenness was formed on the surface, not only the light scattering can be used to suppress the damage caused by the incident angle of the light. The appearance of the fabric with increased reflection (dazzling) changes, and the titanium oxide inside the fiber can also be used to obtain functions such as anti-transmission and UV shielding. The results are shown in the following table.

[Example 17] Except that the polymer 2 was changed to polytrimethylene terephthalate (PPT), the rest were carried out according to Example 1.

In Example 17, in conjunction with the rubber elastic properties of PPT, not only a texture with a lighter feel and excellent softness is presented, but also the stretching function can be greatly improved. Moreover, since the refractive index of PPT is lower than that of PET, the color developing property of the obtained fabric is also excellent. The results are shown in the following table.

[Example 18] Polyethylene terephthalate (SSIA-PEG copolymerized PET, melt viscosity: 100Pa·s, melting point: 233°C), nylon 6-nylon 66 copolymer (N6-66 copolymer, melt viscosity: 240Pa·s, melting point: 195°C) was prepared as polymer 2 series, nylon was prepared as polymer 3 series 6 (N6, melt viscosity: 190Pa·s, melting point: 223℃).

After the polymers were melted at 280°C, the weight ratio of polymer 1/polymer 2/polymer 3 was 20/40/40 was measured, and then flowed into the spinneret assembled with the composite spinning nozzle shown in Figure 5. in the component. Like the flat composite fiber shown in Fig. 2(a), polymer 1 is arranged in the innermost layer, and polymer 2 and polymer 3 are joined to form a side-by-side composite structure in the outermost layer, and are discharged from the discharge hole. into the polymer.

After cooling and solidifying the spouted composite polymer stream, an oil agent is given, and it is coiled at a spinning speed of 1500m/min, and then stretched between rollers heated to 90°C and 130°C to produce 56dtex-36 pieces (fiber diameter 12μm). ) composite fibers.

The obtained conjugate fiber was woven, subjected to 80°C scouring treatment and 130°C wet heat treatment, and then treated in a 1 mass % sodium hydroxide aqueous solution (bath ratio 1:50) heated to 90°C, and it was easily soluble. Polymer 1 of polymer was removed by more than 99%. Then, heat setting was performed at 180° C. to obtain a fabric composed of multifilaments composed of flat hollow fibers having a flatness of 1.8, a hollow ratio of 20%, and a crimp number of 12 threads/cm as shown in FIG. 6( a ).

In Example 18, not only an excellent light-weight feeling but also a texture more excellent in softness can be obtained in conjunction with the nylon properties which are lower in density than polyester and low in elasticity. The results are shown in the following table.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 polymer Polymer 1 SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET Polymer 2 IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET Polymer 3 PET PET PET PET (melting point of polymer 3) - (melting point of polymer 2) 22℃ 22℃ 22℃ 22℃ Weight ratio (polymer 1/2/3) 20/40/40 20/40/40 20/40/40 30/35/35 composite fiber Section shape flat leafy flat leafy flat composite construction Figure 3(a) Figure 3(b) Figure 3(c) Figure 3(d) Variability (RB/RA) 1.8 1.2 1.7 1.7 Connected width (μm) 0.5 0.3 0.4 0.5 Fiber diameter (μm) 12 12 12 12 The ratio of connection width to fiber diameter (%) 4 3 4 4 hollow fiber Section shape Figure 6(b) Figure 7(b) Figure 6(c) Figure 6(b) Flatness 1.8 1.0 1.7 1.7 Hollow rate (%) 18 18 18 19 Opening width (μm) 0.5 0.4 0.4 0.5 Fiber diameter (μm) 12 12 12 12 Ratio of opening to fiber diameter (%) 4 3 4 4 Number of crimped teeth (tooth/cm) 17 19 17 14 Multifilament Variation coefficient CV (%) of the rotation angle of the long axis 27 - 25 29

[Table 2] Table 2 Example 5 Example 6 Example 7 Comparative Example 1 polymer Polymer 1 SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET Polymer 2 IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET PET Polymer 3 PET PET PET PET (melting point of polymer 3) - (melting point of polymer 2) 22℃ 22℃ 22℃ 0℃ Weight ratio (polymer 1/2/3) 20/40/40 20/40/40 20/40/40 20/40/40 composite fiber Section shape flat round flat flat composite construction Figure 3(a) Figure 1(c) Figure 10 Figure 3(a) Variability (RB/RA) 1.3 1.0 1.8 1.8 Connected width (μm) 0.4 0.4 0.4 0.5 Fiber diameter (μm) 12 12 12 12 The ratio of connection width to fiber diameter (%) 4 3 3 4 hollow fiber Section shape Figure 6(b) Figure 7(a) Figure 9 Figure 6(b) Flatness 1.3 1.0 1.8 1.8 Hollow rate (%) 18 18 18 18 Opening width (μm) 0.4 0.4 0.4 0.5 Fiber diameter (μm) 12 12 12 12 Ratio of opening to fiber diameter (%) 4 3 3 4 Number of crimped teeth (tooth/cm) 19 twenty one 12 0 Multifilament Variation coefficient CV (%) of the rotation angle of the long axis 31 - 38 6

[table 3] table 3 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 8 polymer Polymer 1 SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET - SSIA-PEG copolymerized PET Polymer 2 PET IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET Polymer 3 PET PET PET PET (melting point of polymer 3) - (melting point of polymer 2) 0℃ 22℃ 22℃ 22℃ Weight ratio (polymer 1/2/3) 20/40/40 20/40/40 20/40/40 20/40/40 composite fiber Section shape flat round round flat composite construction Figure 3(a) Figure 4(b) Figure 4(a) Figure 3(a) Variability [RB/RA) 1.8 1.0 1.8 1.8 Connected width (μm) 0.5 0.4 - 1.0 Fiber diameter (μm) 12 12 13 12 The ratio of connection width to fiber diameter (%) 4 3 - 8 hollow fiber Section shape Figure 6(b) Figure 8 Figure 4(a) Figure 6(b) Flatness 1.8 1.0 1.0 1.8 Hollow rate (%) 18 18 20 16 Opening width (μm) 0.5 0.4 - 1.0 Fiber diameter (μm) 12 12 12 12 Ratio of opening to fiber diameter (%) 4 3 - 8 Number of crimped teeth (tooth/cm) 54 0 twenty three 17 Multifilament Variation coefficient CV (%) of the rotation angle of the long axis 69 - - 26

[Table 4] Table 4 Example 9 Example 10 Example 11 Example 12 polymer Polymer 1 SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET Polymer 2 IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET Polymer 3 PET PET PET PET (melting point of polymer 3) - (melting point of polymer 2) 22℃ 22℃ 22℃ 22℃ Weight ratio (polymer 1/2/3) 20/40/40 20/60/20 20/20/60 10/45/45 composite fiber Section shape flat flat flat flat composite construction Figure 3(a) Figure 3(a) Figure 3(a) Figure 3(a) Variability (RB/RA) 1.8 1.8 1.8 1.8 Connected width (μm) 1.9 0.5 0.5 0.3 Fiber diameter (μm) 12 12 12 12 The ratio of connection width to fiber diameter (%) 16 4 4 2 hollow fiber Section shape Figure 6(b) Figure 6(b) Figure 6(b) Figure 6(b) Flatness 1.8 1.8 1.8 1.8 Hollow rate (%) 12 18 18 8 Opening width (μm) 1.9 0.5 0.5 0.3 Fiber diameter (μm) 12 12 12 12 Ratio of opening to fiber diameter (%) 16 4 4 2 Number of crimped teeth (tooth/cm) 17 twenty two 7 18 Multifilament Variation coefficient CV (%) of the rotation angle of the long axis 27 41 11 33

[table 5] table 5 Example 13 Example 14 Example 15 Example 16 polymer Polymer 1 SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET Polymer 2 IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET IPA copolymerized PET Polymer 3 PET PET PET TiO ₂ contains PET (melting point of polymer 3) - (melting point of polymer 2) 22℃ 22℃ 22℃ 22℃ Weight ratio (polymer 1/2/3) 30/35/35 20/40/40 20/40/40 20/40/40 composite fiber Section shape flat flat flat flat composite construction Figure 3(a) Figure 3(a) Figure 3(a) Figure 3(a) Variability (RB/RA) 1.8 1.8 1.8 1.8 Connected width (μm) 0.8 0.7 1.0 0.5 Fiber diameter (μm) 12 17 twenty four 12 The ratio of connection width to fiber diameter (%) 7 4 4 4 hollow fiber Section shape Figure 6(b) Figure 6(b) Figure 6(b) Figure 6(b) Flatness 1.8 1.8 1.8 1.8 Hollow rate (%) 27 18 18 18 Opening width (μm) 0.8 0.7 1.0 0 Fiber diameter (μm) 12 17 twenty four 12 Ratio of opening to fiber diameter (%) 6 4 4 4 Number of crimped teeth (tooth/cm) 15 12 10 17 Multifilament Variation coefficient CV (%) of the rotation angle of the long axis 25 18 16 27

[Table 6] Table 6 Example 17 Example 18 polymer Polymer 1 SSIA-PEG copolymerized PET SSIA-PEG copolymerized PET Polymer 2 PPT N6-66 copolymer Polymer 3 PET N6 (melting point of polymer 3) - (melting point of polymer 2) 21℃ 38℃ Weight ratio (polymer 1/2/3) 20/40/40 20/40/40 composite fiber Section shape flat flat composite construction Figure 3(a) Figure 2(a) Variability (RB/RA) 1.8 1.8 Connected width (μm) 0.5 - Fiber diameter (μm) 12 12 The ratio of connection width to fiber diameter (%) 4 - hollow fiber Section shape Figure 6(b) Figure 6(a) Flatness 1.8 1.8 Hollow rate (%) 17 20 Opening width (μm) 1 - Fiber diameter (μm) 12 12 Ratio of opening to fiber diameter (%) 4 - Number of crimped teeth (tooth/cm) twenty four 13 Multifilament Variation coefficient CV (%) of the rotation angle of the long axis 45 twenty two

[Table 7] Table 7 Example 1 Example 2 Example 3 Example 4 texture evaluation Lightweight feeling (apparent density (g/cm ³ )) ◎(0.33) ◎(0.34) ◎(0.31) ◎(0.31) Flexibility (Bending hardness B×10 ^-2 (gf・cm ² /cm)) ◎(0.9) ◎(0.8) ◎(0.9) ◎(0.6) Rebound (bending recovery 2HB×10 ^-2 (gf・cm/cm)) ◎(0.9) ◎(1.0) ◎(0.8) ◎(1.0) Smoothness (Coefficient of Friction) ◎(0.3) ○(0.6) ○(0.7) ◎(0.4) Roughness (friction variation × 10 ^-2 ) ◎(0.9) ○(0.5) ◎(0.9) ◎(0.9) Functional evaluation Water absorption and quick drying (water diffusion time (min)) ○(25) ◎(20) ◎(15) ◎(20) Stretchability (fabric elongation (%)) ◎(16) ◎(17) ◎(16) ◎(17) Wear resistance ◎(Level 4) ◎(Level 4) ◎(Level 4) ◎(Level 4)

[Table 8] Table 8 Example 5 Example 6 Example 7 Comparative Example 1 texture evaluation Lightweight feeling (apparent density (g/cm ³ )) ○(0.36) ○(0.38) ◎(0.30) ○(0.44) Flexibility (Bending hardness B×10 ^-2 (gf・cm ² /cm)) ◎(0.8) ◎(0.7) ◎(0.8) ×(2.8) Rebound (bending recovery 2HB×10 ^-2 (gf・cm/cm)) ○(1.1) ○(1.2) ◎(1.0) ×(2.7) Smoothness (Coefficient of Friction) ◎(0.4) ○(0.5) ◎(0.3) ◎(0.2) Roughness (friction variation × 10 ^-2 ) ○(0.7) ○(0.5) ◎(1.1) ×(0.2) Functional evaluation Water absorption and quick drying (water diffusion time (min)) ○(25) 0(30) ◎(20) ×(45) Stretchability (fabric elongation (%)) ◎(20) ◎(24) 0(13) ×(0) Wear resistance ◎(Level 4) ◎(Level 4) ◎(Level 4) ◎(Level 4)

[Table 9] Table 9 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 8 texture evaluation Lightweight feeling (apparent density (g/cm ³ )) ◎(0.32) ○(0.44) ×(0.48) ○(0.36) Flexibility (Bending hardness B×10 ^-2 (gf・cm ² /cm)) ◎(0.8) ×(2.6) ×(2.0) ○(1.1) Rebound (bending recovery 2HB×10 ^-2 (gf・cm/cm)) ○(1.1) ×(2.4) ×(2.0) ○(1.3) Smoothness (Coefficient of Friction) ○(0.8) ○(0.3) ○(0.5) ○(0.6) Roughness (friction variation × 10 ^-2 ) ×(0.4) ×(0.2) ○(0.5) ◎(0.9) Functional evaluation Water absorption and quick drying (water diffusion time (min)) ○(25) ×(45) 0(30) 0(25) Stretchability (fabric elongation (%)) ○(10) ×(0) ◎(17) ○(14) Wear resistance ◎(Level 4) ◎(Level 4) ◎(Level 4.5) ○(Level 3.5)

[Table 10] Table 10 Example 9 Example 10 Example 11 Example 12 texture evaluation Lightweight feeling (apparent density (g/cm ³ )) ○(0.42) ○(0.38) ○(0.4) ○(0.38) Flexibility (Bending hardness B×10 ^-2 (gf・cm ² /cm)) ○(1.8) ○(1.9) ◎(0.8) ○(1.3) Rebound (bending recovery 2HB×10 ^-2 (gf・cm/cm)) ○(1.9) ○(1.6) ○(1.2) ○(1.4) Smoothness (Coefficient of Friction) ○(1.0) ◎(0.3) ◎(0.3) ◎(0.3) Roughness (friction variation × 10 ^-2 ) ◎(0.9) ○(0.6) ○(0.6) ◎(0.9) Functional evaluation Water absorption and quick drying (water diffusion time (min)) ◎(20) ○(25) ○(35) ○(25) Stretchability (fabric elongation (%)) ○(10) ○(14) ○(5) ◎(16) Wear resistance ○ (Level 3) ◎(Level 4) ◎(Level 4) ◎(Level 4.5)

[Table 11] Table 11 Example 13 Example 14 Example 15 Example 16 texture evaluation Lightweight feeling (apparent density (g/cm ³ )) ◎(0.33) ◎(0.31) ◎(0.29) ◎(0.33) Flexibility (Bending hardness B×10 ^-2 (gf・cm ² /cm)) ◎(0.9) ○(1.2) ○(1.8) ◎(0.9) Rebound (bending recovery 2HB×10 ^-2 (gf・cm/cm)) ◎(0.6) ◎(0.8) ◎(0.6) ◎(0.9) Smoothness (Coefficient of Friction) ◎(0.3) ○(0.5) ○(0.7) ○(0.4) Roughness (friction variation × 10 ^-2 ) ◎(0.9) ◎(1.0) ◎(1.1) ◎(0.9) Functional evaluation Water absorption and quick drying (water diffusion time (min)) ○(25) ○(25) ○(30) ○(25) Stretchability (fabric elongation (%)) ○(13) ○(14) ○(12) ◎(16) Wear resistance ○(Level 3.5) ◎(Level 4) ◎(Level 4) ◎(Level 4)

[Table 12] Table 12 Example 17 Example 18 texture evaluation Lightweight feeling (apparent density (g/cm ³ )) ◎(0.31) ◎0.28) Flexibility (Bending hardness B×10 ^-2 (gf・cm ² /cm)) ◎(0.6) ◎(0.6) Rebound (bending recovery 2HB×10 ^-2 (gf・cm/cm)) ○(1.6) ○(2.0) Smoothness (Coefficient of Friction) ○(0.5) ○(0.5) Roughness (friction variation × 10 ^-2 ) ○(0.6) ○(0.8) Functional evaluation Water absorption and quick drying (water diffusion time (min)) ◎(20) ○(35) Stretchability (fabric elongation (%)) ◎(27) ○(14) Wear resistance ◎(Level 4) ○(Level 3.5)

In addition, the meanings of the abbreviations in the table are as follows. PET: polyethylene terephthalate PEG: polyethylene glycol SSIA: sodium isophthalate-5-sulfonate IPA: isophthalic acid PPT: polyethylene terephthalate N6: nylon 6 N6-66 Copolymer: nylon 6-nylon 66 copolymer TiO ₂ : titanium oxide

The present invention has been described with reference to details and specific embodiments, but without departing from the spirit and scope of the present invention, various changes and corrections can be added, which can be easily conceived by those skilled in the art. This application is based on Japanese Patent Application (Japanese Patent Application No. 2020-137899) filed on August 18, 2020 and Japanese Patent Application (Japanese Patent Application No. 2020-194085) filed on November 24, 2020, Reference is made to its content and cited in this case. (Industrial Availability)

The conjugated fibers, hollow fibers and multifilaments of the present invention can obtain a textile material excellent in wearing comfort that achieves a soft texture with moderate rebound and bulkiness by densely controlling the void structure between the fibers and between the fibers. Therefore, the composite fibers, hollow fibers and multifilaments of the present invention can be applied to general clothing materials such as jackets, skirts, trousers, and underwear, as well as sports clothing and clothing materials. In addition, they can also be applied to interior products such as carpets and sofas by taking advantage of their comfort. ; Vehicle interior parts such as car seats; Various fiber products for daily use such as cosmetics, cosmetic masks, health products, etc.

x: easily soluble polymer y: Insoluble polymer on the low melting point side z: Insoluble polymer on the high melting point side a1, a2: the intersection of the fiber surface and the inscribed circle b1, b2: the intersection of the fiber surface and the circumcircle c1, c2: the 2 farthest points on the periphery of the fiber d1, d2: A straight line that passes through the midpoint of the straight line connected by the two farthest points on the outer periphery of the fiber and is orthogonal to the point of intersection with the fiber surface A: A circle having the largest diameter within the range where the circumference of the inscribed circle that is inscribed at least at two points on the fiber surface and exists only inside the fiber does not intersect the fiber surface B: A circle having the smallest diameter within a range where the circumference of a circumscribed circle that circumscribes the fiber surface at at least two points and exists only inside the fiber does not intersect the fiber surface G: Fiber Center H: hollow part 1: Within a straight line passing through the center of the fiber and dividing the fiber cross section into two equal parts, with the straight line as the boundary, in the left and right or up and down fiber cross sections, the difference between the insoluble polymer on the high melting point side and the insoluble polymer on the low melting point side The area ratio is a straight line in the range of 100:0 to 70:30 in either fiber cross section and 30:70 to 0:100 in the other fiber cross section S: a straight line passing through the fiber center G and parallel to the connecting part W: The width of the connecting portion in the vertical direction with respect to the straight line S S': a straight line passing through the fiber center G and parallel to the opening W': The width of the opening in the vertical direction with respect to the straight line S' 1: Metering board 2: Distribution board 3: Spit out board

In Fig. 1, Fig. 1(a), Fig. 1(b), Fig. 1(c), and Fig. 1(d) are schematic diagrams of the cross-sectional structure of the conjugate fiber of the present invention. In Fig. 2, Fig. 2(a), Fig. 2(b), and Fig. 2(c) are schematic diagrams of the cross-sectional structure of the conjugate fiber of the present invention. In Fig. 3 , Fig. 3(a), Fig. 3(b), Fig. 3(c), and Fig. 3(d) are schematic diagrams of the cross-sectional structure of the conjugate fiber of the present invention. In Fig. 4, Fig. 4(a) and Fig. 4(b) are schematic diagrams of the cross-sectional structure of a conventional conjugated fiber. Fig. 5 is a schematic diagram of the cross-sectional structure of the multifilament of the present invention; Fig. 5(a) is a diagram for understanding the flatness; Fig. 5(b) is for understanding the coefficient of variation CV of the rotation angle of the long axis of the fiber in the multifilament The dotted lines in the outer frame refer to the top, bottom, left, and right edges of the captured image. In Fig. 6, Fig. 6(a), Fig. 6(b), and Fig. 6(c) are schematic diagrams of cross-sectional structures of fibers constituting the multifilament of the present invention. In FIG. 7 , FIG. 7( a ) is a schematic view of the cross-sectional structure of the fiber constituting the multifilament of Example 6; FIG. 7( b ) is a schematic view of the cross-sectional structure of the fiber constituting the multifilament of Example 2. 8 is a schematic diagram of a cross-sectional structure of fibers constituting the multifilament of Comparative Example 3. FIG. Fig. 9 is a schematic diagram showing the cross-sectional structure of the fibers constituting the multifilament of the present invention. Fig. 10 is a schematic diagram showing a cross-sectional structure of an example of a conjugate fiber from which the multifilament of the present invention can be produced. Fig. 11 shows an example of the crimped form of the fibers constituting the multifilament of the present invention. Fig. 12 is a cross-sectional view illustrating a method for producing the conjugate fiber of the present invention.

x: easily soluble polymer

y: Insoluble polymer on the low melting point side

z: Insoluble polymer on the high melting point side

a1, a2: the intersection of the fiber surface and the inscribed circle

b1, b2: the intersection of the fiber surface and the circumcircle

A: A circle having the largest diameter within the range where the circumference of the inscribed circle that is inscribed at least at two points on the fiber surface and exists only inside the fiber does not intersect the fiber surface

B: A circle having the smallest diameter within a range where the circumference of a circumscribed circle that circumscribes the fiber surface at at least two points and exists only inside the fiber does not intersect the fiber surface

G: Fiber Center

S: a straight line passing through the fiber center G and parallel to the connecting part

W: The width of the connecting portion in the vertical direction with respect to the straight line S

Claims (10)

A composite fiber, in the cross section of the fiber, two or more kinds of polymers with different dissolving rates to solvents are laminated from the center of the fiber toward the surface of the fiber; The innermost layer comprising the above-mentioned fiber center contains a readily soluble polymer; In at least one layer other than the above-mentioned innermost layer, two types of poorly soluble polymers having different melting points exist unevenly. The conjugate fiber according to claim 1, wherein, in the cross section of the fiber, the relationship between the diameter of the inscribed circle RA and the diameter of the circumscribed circle RB of the fiber is 1.2≦RB/RA≦2.4. The conjugate fiber according to claim 1 or 2, wherein, in the cross section of the fiber, the easily soluble polymer is connected from the center of the fiber to the surface of the fiber, and the connecting width is 10% or less of the fiber diameter. The conjugate fiber according to any one of claims 1 to 3, wherein, in the cross section of the fiber, the outermost layer contains the easily soluble polymer. A hollow fiber in which the above-mentioned readily soluble polymer is removed from the conjugate fiber of any one of claims 1 to 4. A multifilament, which is a multifilament containing flat hollow fibers; The coefficient of variation CV of the rotation angle of the long axis of the flat hollow fiber is 15 to 50%. The multifilament according to claim 6, wherein the flatness of the cross section of the flat hollow fiber is 1.2 or more. The multifilament according to claim 6 or 7, wherein the flat hollow fiber-based fiber is composed of at least two kinds of polymers having different melting points in cross section. The multifilament according to any one of claims 6 to 8, wherein the flat hollow fiber has an opening from the center of the fiber to the direction of the fiber surface; The width of the above-mentioned opening is 10% or less of the fiber diameter. A fiber product, a part of which contains the conjugate fiber of any one of claims 1 to 4, the hollow fiber of claim 5, or the multifilament of any one of claims 6 to 9.

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