JP7263778B2 - latent crimp yarn - Google Patents

Description

TECHNICAL FIELD The present invention relates to a latently crimped yarn in which eccentric core-sheath fibers with different fiber diameters are uniformly dispersed and mixed in a yarn bundle.

Fibers made from thermoplastic polymers such as polyester and polyamide have various excellent properties such as mechanical properties and dimensional stability. It is used and the required characteristics are becoming more diverse.

Considering the recent trends in textiles for apparel, there is a high demand for stretch materials that appeal to fit and movement when worn. Textiles are being actively developed. In particular, the provision of bulkiness expresses a soft touch with a swelling of the fine voids that exist between the yarn bundles and excellent heat retention due to the heat insulation effect of the enclosed air. It can be used widely from general clothing such as outerwear to sports clothing.

Various methods have been proposed for imparting stretch to the raw yarns that make up the fabric. There is a method of mixing polyurethane fibers, but there have been problems such as lack of stretchability and the complication of the dyeing process due to the mixing of other materials.

In order to solve these problems, there is a disclosure of a technology related to latent crimp-developing yarn in which different polymers are laminated side-by-side and a spiral structure is developed by the difference in shrinkage.

In Patent Document 1, a side-by-side type composite yarn of polyethylene terephthalate (PET) having an intrinsic viscosity difference or an intrinsic viscosity difference, and in Patent Document 2, a latent crimp yarn such as a side-by-side type composite yarn using polytrimethylene terephthalate (PTT) and PET. is proposed. The latent crimped yarn referred to here is a yarn that is crimped into a three-dimensional spiral structure due to the difference in contraction rate between the polymers laminated on the left and right sides by applying heat treatment or the like. By stretching and shrinking, it becomes a fiber with stretchability.

Further, Patent Documents 3 and 4 propose techniques for increasing the bulkiness of latently crimped yarns.

In Patent Document 3, the conjugate ratio between the single fibers is changed to express the variation in the curvature of the polymer interface. The crimps form independently without intermeshing. For this reason, it is described that inter-fiber voids are developed in the yarn bundle according to the difference in crimp configuration, and a fabric made of this fiber can have both stretchability and bulkiness.

Patent Document 4 proposes a mixed filament yarn composed of three or more types of side-by-side composite yarns having different finenesses. In Patent Document 4, since a plurality of types of crimps according to the fineness of single fibers are mixed, in addition to the inter-fiber voids generated by the crimped structures of different sizes, the inter-fiber voids generated by the difference in crimp configuration give a feeling of fullness. It is described to be a fabric with

Japanese Patent Publication No. 44-2504 (Claims) Japanese Patent Application Laid-Open No. 2005-113369 (Claims) Japanese Patent Application Laid-Open No. 2000-212838 (Claims) Japanese Patent Application Laid-Open No. 2002-285428 (Claims)

In the latently crimped yarn proposed in Patent Document 1 and Patent Document 2, since all the constituent single fibers have the same composite cross section, the crimp form such as the size of the crimp that the single fiber naturally develops varies. Adjacent single fibers are similar. Therefore, single fibers having crimps of the same size may be entangled so as to mesh with each other, resulting in a latently crimped yarn with low bulkiness, such as a twisted yarn of a plurality of single fibers. Since the single fibers are bundled together in such a multifilament yarn bundle, when it is used as a cloth as it is, it is unlikely to be bulky, and the surface quality and touch may be deteriorated due to embossing. there were.

In addition, in the latent crimped yarn in which the composite ratio is changed for each fiber as proposed in Patent Document 3, if the fiber cross section is not designed precisely, there is no significant difference in the crimp shape for each single fiber. It is very difficult to express it, and the expected bulkiness may not be obtained. For this reason, the crimp phase is almost aligned as in Patent Documents 1 and 2, and when it is made into a fabric, it is less likely to be bulky, and the surface quality and tactile feel are reduced due to embossing and the like. there was a case.

On the other hand, in Patent Document 4, although there is a possibility that a difference in crimp shape depending on the single fiber fineness can be expressed, since all the single fiber cross sections are flat cross sections, the directionality of the single fibers tends to be uniform, Even in this case, it becomes difficult to form good gaps between the yarn bundles. For this reason, in order to obtain the latent crimped yarn having the bulkiness demanded in recent years, it was necessary to perform complicated high-order processing and the like. In addition, in Patent Document 4, due to the flat cross section, single fibers tend to form groups for each fiber diameter, and when they are separated in the yarn bundle, roughness, streak defects, etc. occur. There was a problem that it was difficult to obtain the texture and surface quality of the fabric.

The above objects are achieved by the following means. i.e.
(1) Two or more types of eccentric core-sheath composite fibers with different fiber diameters are dispersed and mixed in the yarn bundle, and the maximum value (Dmax) and the minimum value (Dmax) of the central fiber diameter of the single fibers constituting the yarn bundle Dmin) ratio (Dmax/Dmin) of 1.20 or more .
(2) The latently crimped yarn according to (1), wherein all fibers contained in the yarn bundle have an irregularity of less than 1.20.
(3) The latently crimped yarn according to (1) or (2), wherein all the fibers contained in the yarn bundle have the same area ratio of the core component to the single fiber cross section.
(4) A textile product at least partially containing the latently crimped yarn according to any one of (1) to (3).
is.

In the latently crimped yarn of the present invention, eccentric core-sheath fibers having different fiber diameters are evenly dispersed and mixed in the yarn bundle. When crimps are developed, eccentric core-sheath fibers with different fiber diameters weave crimps with various sizes to form specific inter-fiber voids in the yarn bundle, which are different in size. By adding the effect of crimping, it expresses excellent bulkiness and flexible elongation characteristics that have not existed in the past.

The woven or knitted fabric obtained from the latently crimped yarn of the present invention has a smooth surface due to the characteristic gaps between the fibers of the yarn bundle, and has a bulky and flexible elongation property, and is used in a wide range of applications. It becomes a textile for comfortable clothing that is possible.

It is an example of a single fiber constituting the latently crimped yarn of the present invention, and is a fiber cross section for explaining the center of gravity position in the fiber cross section. It is an example of the thin skin eccentric core-sheath cross section of the present invention, and is a fiber cross section for explaining the minimum thickness (S) in the fiber cross section. BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the schematic of the fiber cross section of the latent crimp yarn of this invention. 1 is a schematic diagram of an example of the fiber diameter distribution of single fibers that constitute the latently crimped yarn of the present invention. FIG. It is an example of the distribution hole arrangement in the final distribution plate for obtaining the latently crimped yarn having the eccentric core-sheath cross section of the present invention. Fig. 3 is an embodiment of the distribution hole arrangement in the final distribution plate for obtaining the thin-skinned eccentric core-sheath section of the present invention; It is an example of the ejection hole arrangement in the ejection plate for obtaining the latently crimped yarn of the present invention.

The present invention will be described in detail below along with preferred embodiments.

A first requirement of the latently crimped yarn of the present invention is that two or more types of eccentric core-sheath composite fibers with different fiber diameters are dispersed and mixed in the yarn bundle.

The eccentric core-sheath cross section referred to in the present invention is illustrated in FIG. The center of gravity is the center of gravity a, and the center of the single fiber cross section is the center point c.

The eccentric core-sheath composite fiber has a single fiber cross section composed of two types of polymers, the polymer B which is the sheath component completely covers the polymer A which is the core component, and the position a of the center of gravity of the core component is the single fiber It means a fiber having an eccentric core-sheath composite cross section different from the cross-sectional center c.

When a fiber having such an eccentric core-sheath type cross section is subjected to heat treatment or the like, the single fiber is greatly curved according to the shrinkage difference of the core/sheath component, and a three-dimensional spiral crimp like a coil is obtained. is expressed, and good stretchability is expressed by this spiral crimp.

Regarding the degree of spiral crimping, the larger the center-to-center distance, which is the distance between the center of gravity a and the center point c in the cross section of the conjugate fiber, the finer the crimp. In order to obtain a latently crimped yarn having bulkiness and flexible elongation properties, it is preferable to have a thin eccentric core-sheath cross-section that allows a longer center-of-gravity distance between the core and the sheath.

The thin-skinned eccentric core-sheath cross section referred to here means an eccentric core-sheath cross section that satisfies the following requirements.
(A) The ratio S/D of the minimum thickness S of the sheath component covering the core component to the fiber diameter D of the single fiber is 0.01 to 0.10.
(B) The perimeter portion having a thickness within 1.05 times the minimum thickness S occupies 30% or more of the total perimeter of the cross section of the single fiber.

FIG. 2 illustrates the eccentric core-sheath cross section of the thin skin. Horizontal hunting is the sheath component, 30 deg hunting is the core component, S is the minimum thickness of the sheath component, and D is the fiber diameter of the single fiber.

The fiber diameter D, the minimum thickness S of the sheath component, and the ratio S/D between the minimum thickness S of the sheath component and the fiber diameter D of the single fiber are obtained as follows.

That is, the latently crimped yarn is embedded in an embedding agent such as epoxy resin as a yarn bundle, and the cross section of this is imaged with a scanning electron microscope (SEM) or the like at a magnification at which 10 or more single fibers can be observed. to shoot. In each photographed image, the cross-sectional area Af of the single fiber is measured using the image analysis software "WinROOF2015" manufactured by Mitani Shoji Co., Ltd., and the diameter of the perfect circle having the same area as this area Af is calculated. A value obtained by rounding μm to the second decimal place is the fiber diameter D referred to in the present invention.

In addition, using the image obtained by measuring the fiber diameter D of the single fibers, the minimum thickness S of the sheath component covering the core component for 10 single fibers is the minimum thickness S referred to in the present invention. be. Furthermore, the fiber diameter D and the minimum thickness S of these single fibers are measured in units of μm, and S/D is calculated for the same single fiber. The above operation is calculated for 10 single fibers, a simple numerical average value is obtained, and the value is obtained by rounding to the second decimal place.

The second important requirement for the latently crimped yarn of the present invention is that "at least two types of eccentric core-sheath composite fibers having different fiber diameters are mixed in the yarn bundle". An example of a yarn bundle cross section is illustrated in FIG.

In the present invention, the state in which two or more types of eccentric core-sheath composite fibers with different fiber diameters are present in the yarn bundle means that when all the single fibers are evaluated with the above-described fiber diameter in the yarn bundle cross section, there are two or more If two types of eccentric core-sheath composite fibers with different fiber diameters are present in the yarn bundle, there are two fiber diameter distributions (4-( Take a) and (c)).

That is, a single fiber group having a fiber diameter falling within each distribution range (distribution width) is defined as "one type", and in the measurement results of all the single fibers constituting the latently crimped yarn, this fiber diameter distribution is shown in FIG. The presence of two or more as in the present invention means that "two or more types of eccentric core-sheath composite fibers with different fiber diameters are present in the yarn bundle". The fiber diameter distribution width (4-(e), (f)) referred to here means the median fiber diameter (4-(b), (d )) within a range of ±5%.

When the eccentric core-sheath composite fiber used in the present invention is subjected to heat treatment or the like to develop crimp, the single fiber takes a crimped form depending on the fiber diameter. A plurality of crimps of different sizes coexist within the yarn bundle. From a local point of view, crimps of different sizes do not mesh with each other and produce an effect of mutually excluding each other between single fibers. It is preferable to set a large difference in crimp shape between the single fibers in order to obtain the desired product.

This can be evaluated by the relationship between the maximum value (Dmax) and the minimum value (Dmin) of the central fiber diameter of the single fibers constituting the yarn bundle, and the ratio of Dmax to Dmin (Dmax/Dmin) must be 1.20 or more. Within this range, crimp phase shift occurs between single fibers, fine inter-fiber voids are developed in the yarn bundle, and the object of the present invention can be satisfactorily achieved.

On the other hand, if it is only the phase shift effect, the higher the Dmax/Dmin, the more effective it becomes, but the more difficult it is for the single fibers to get caught, and the more favorable the removal effect is, the more Dmax/Dmin A more preferable range is 1.30 to 2.00 times, and within such a range, the difference in crimp configuration between the single fiber groups is expanded, resulting in a crimp phase shift effect. can be obtained more remarkably, so excellent bulkiness can be obtained.

In a yarn bundle containing eccentric core-sheath fibers with different fiber diameters as described above, in order to more effectively reduce the effect of expulsion between single fibers and each crimp to stretchability, it is necessary to use fibers with different fiber diameters as yarns. It is important that they are uniformly mixed in the bundle, and in the present invention, it is necessary that two or more types of eccentric core-sheath composite fibers with different fiber diameters are dispersed and mixed in the yarn bundle. This dispersed and mixed state means that at least one kind of single fibers among the single fibers having different fiber diameters are evenly present in the yarn bundle when the cross section of the yarn bundle is observed. means

As described above, in a yarn bundle in which fibers with different fiber diameters are present evenly and uniformly, a single fiber with a different fiber diameter exists around a certain single fiber. When heat treatment or the like is applied, the single fibers independently develop crimps, and the phase alignment of the crimped structure is suppressed between the single fibers surrounding the single fibers, and the single fiber-to-single fiber It is possible to exhibit the elimination effect of

This effect is especially excellent when the latently crimped yarn of the present invention is crimped by heat treatment or the like. That is, in contrast to the prior art in which crimping occurs in such a manner that single fibers entwine adjacent single fibers, the elimination effect between single fibers may be reduced as a whole, the latently crimped yarn of the present invention Since fibers with different fiber diameters are basically adjacent to each other, their crimping behaviors are different, so that biting and strong entanglement between single fibers are greatly suppressed. In addition, after the yarn bundle is crimped, fibers with a small fiber diameter are present between fibers with a large fiber diameter, so that even after crimping, the single fibers are suppressed from being caught. By having a spiral structure with different sizes, there is a larger gap between the single fibers, and it has a pleasant rebound feeling not only in the fiber axis direction (stretching direction) but also in the cross-sectional direction (compression direction), and can be repeatedly compressed. Even during deformation, by continuing to eliminate between single fibers, good stretch and bulkiness can be maintained with high durability.

The state in which two or more types of eccentric core-sheath composite fibers with different fiber diameters are dispersed and mixed in the yarn bundle, which is a requirement for exhibiting the effects of the present invention, is at least It can be evaluated by observing the adjacent filament group ratio of one type of single fiber.

The term "adjacent filament group" as used in the present invention means a set of eight or more monofilaments having the same fiber diameter, which are adjacently connected in the cross section of the latent crimped yarn. When the total number of single fibers constituting a group is Ns and the total number of single fibers of the fiber is N, it is represented by Ns/N. 3-(a) and 3-(b) in FIG. There is no single fiber having a fiber diameter of . In addition, when eight or more filaments are arranged adjacent to each other as in section 3-(c), the group is defined as an adjacent filament group. Furthermore, when a plurality of adjacent filament groups exist in the cross section of the latently crimped yarn, the total number of single fibers constituting the adjacent filament groups is the total number Ns of single fibers constituting the adjacent filament groups.

That is, the adjacent filament group ratio referred to in the present invention is 10 images randomly extracted on the yarn bundle based on the results of classifying the yarn cross-section images taken when obtaining the fiber diameter and classifying them according to the fiber diameter. counts the number of single fibers that constitute a group of adjacent filaments having a certain fiber diameter. From this measurement result, the adjacent filament group ratio=(the number of single fibers constituting the adjacent filament group)/(the total number of single fibers having the fiber diameter of interest)×100 (%) is calculated. The value obtained by rounding off the first decimal place of the simple number average of the measurement results of 10 images was used as the adjacent filament group ratio referred to in the present invention.

When single fibers with different fiber diameters are not uniformly mixed and the existence ratio of one type of single fiber in the cross section of the yarn bundle is biased, which is sometimes seen in the conventional technology, the adjacent filament group ratio is Although the value is high, in the present invention, the adjacent filament group ratio is in the range of 10 to 80%. The state in which the conjugate fibers are dispersed and mixed in the yarn bundle).

Promoting this idea, in the present invention, it is preferable that the value of the adjacent filament group ratio is low, and it is a more preferable range that the adjacent filament group ratio is 10 to 60%. Single fibers having different fiber diameters are present around the single fibers dispersed in the space.

In this way, the good bulkiness due to the inter-fiber voids, which is a feature of the present invention and could not be achieved by the conventional technology, is achieved by the uniform presence of single fibers with different fiber diameters at any location in the yarn bundle. It is preferable that the single fibers are in a dispersed state, and in the process of applying heat treatment or the like to develop crimps or assuming smoothness in yarn processing, the single fibers should have a cross section close to a circle. Specifically, it is preferable that the irregularity of the single fibers constituting the yarn bundle is less than 1.20.

The degree of irregularity referred to here is obtained as follows.

That is, when obtaining the fiber diameter in the cross section of the fiber bundle, the image of the cross section of the fiber bundle is used, and the circumscribed circle diameter, which is the diameter of the perfect circle that circumscribes the single fiber, and the inscribed circle diameter, which is the diameter of the perfect circle that inscribes the single fiber. was calculated as irregularity = diameter of circumscribed circle/diameter of inscribed circle. It should be noted that the closer the value of the irregularity measured by the above method to 1.00, the closer the shape of the single fiber cross section to a perfect circle.

In the case of fibers with irregularity, in the movement within the yarn bundle and the development of a spiral structure that develops crimps, it naturally moves in a direction depending on its cross section. While fibers with similar diameters tend to gather together, fibers with different sizes move freely in all directions around the fiber, creating a state in which they are evenly distributed in the yarn bundle. is suitable for Furthermore, in the present invention, since the fibers constituting the yarn bundle are latently crimped yarns that develop crimps, it is effective that the fibers can move freely in all directions around the fibers. This makes it easier to create a state in which single fibers with different fiber diameters are evenly dispersed. In addition, the closer the single fiber cross section is to a perfect circle, the easier the single fiber will diffuse when receiving a force in the direction perpendicular to the fiber axis, and the better the dispersibility will be. Therefore, it is preferable that all single fibers have an irregularity of less than 1.20.

Promoting this idea, in the present invention, it is preferable that the irregularity of the single fibers is low, and the irregularity of all the single fibers is 1.10 or less as a more preferable range. In addition, within this range, when applied to textiles for clothing, the cross section of the single fiber is close to a circular cross section, so the fabric has excellent appearance such as smoothness of the surface of the fabric and mild gloss due to diffuse reflection of light. As a range in which mild luster and smooth texture are more preferably expressed, a range in which the irregularity of single fiber breakage is 1.05 or less can be mentioned as a particularly preferable range.

In addition, in a yarn bundle in which different single fibers are uniformly dispersed as described above, since the crimp expression of a certain single fiber is restrained by other fibers arranged around it, all the single fibers in the yarn bundle can be treated well. It is preferable that all the single fibers contained in the yarn bundle have the same area ratio of the core component in the cross section in order to develop the crimp effectively and to create good inter-fiber gaps in the yarn bundle.

In the eccentric core-sheath composite yarn, the larger the area ratio of the high-shrinkage component, the higher the force to develop the crimped structure. A single fiber having a low ratio and a low crimp development force may not be able to sufficiently develop a crimped structure due to restraint by other single fibers.

For this reason, the composite ratio (area ratio of the core component) of all the single fibers that make up the latent crimped yarn is the same, and the crimp development force of each single fiber is the same, so that the single fibers are uniform in the yarn bundle. Each single fiber can be crimped even in the form of yarn dispersed in a wide area, and a latently crimped yarn containing many inter-fiber voids between the desired yarn bundles can be obtained.

The fact that all the single fibers constituting the latent crimped yarn have the same area ratio of the core component means that when the area ratio fc of the core component is evaluated for all the single fibers constituting the yarn bundle, fc It means that the variation is 15.0% or less.

The area ratio fc of the core component referred to here is obtained as follows.

That is, the cross section of the latent crimped yarn is photographed in the same manner as for the fiber diameter described above. From the photographed image, using the image analysis software "WinROOF2015" manufactured by Mitani Shoji Co., Ltd., the cross-sectional area Af of the single fiber and the area Ac of the core component were measured in μm ² , and fc = Ac / Af × 100 (% ) is rounded off to the second decimal place.

Furthermore, the fc variation referred to here means that fc is measured for all single fibers constituting the latent crimped yarn by the method described above, and based on the measurement results, fc variation (fcCV%) = (standard deviation of fc /fc)×100(%), and rounded to the second decimal place. If the fc variation is within the range, it can be considered that all the single fibers in the latently crimped yarn have the same fc.

The latently crimped yarn of the present invention preferably has a certain or more toughness in consideration of the processability in higher processing and practical use when processed into a fabric, and the strength at the time of fiber breakage and It is preferable that the elongation is as follows.

The strength of the present invention is the value obtained by dividing the load value at break by the initial fineness obtained by obtaining the load-elongation curve of the fiber under the conditions shown in JIS L1013 (2010), and the elongation is the elongation at break. is the value obtained by dividing by the initial test length. Here, the initial fineness means a value obtained by calculating the weight per 10,000 m from the simple average value obtained by measuring the weight of the unit length of the fiber multiple times.

The strength and elongation referred to here are preferably adjusted by controlling the conditions of the manufacturing process described later according to the intended use, etc., but the standard of the latently crimped yarn of the present invention is the strength is 0.5 to 10.0 cN/dtex and elongation is 5 to 700%, which can be cited as preferred ranges.

When the latently crimped yarn of the present invention is used for general clothing such as innerwear and outerwear, it is preferable that the strength is 1.0 to 4.0 cN/dtex and the elongation is 20 to 40%. In addition, in applications such as sports clothing in which the use environment is severe, it is preferable to set the strength to 3.0 to 5.0 cN/dtex and the elongation to 10 to 40%.

The latently crimped yarn of the present invention can be made into various fiber products as various intermediates such as fiber winding packages, tows, cut fibers, cotton, fiber balls, cords, piles, woven and knitted fabrics, and nonwoven fabrics. . The textile products referred to here can be used for general clothing such as jackets, skirts, pants and underwear, sports clothing, clothing materials, interior products such as carpets, sofas and curtains, and vehicle interiors such as car seats. .

Next, a preferred method for producing the latently crimped yarn of the present invention will be described.

The latently crimped yarn of the present invention must form a state in which two or more types of single fibers having different fiber diameters are dispersed and mixed. This yarn bundle form can be applied by precisely controlling so-called post-mixing, in which separately spun yarns are mixed with an air nozzle or the like. It is preferable to use a spinning mixed fiber method in which the fiber is discharged from the fiber and wound at the same time. In this spinning mixed fiber method, since multiple types of single fibers are bundled at the same time during winding, each single fiber is easily dispersed in the latent crimped yarn, and the discharge hole corresponding to each single fiber on the spinneret It is also possible to change the degree of dispersion in the latently crimped yarn by changing the number and arrangement of . Furthermore, in addition to being able to omit the post-processing step by spinning and mixing, in order to create the yarn bundle form required in the present invention by the post-fiber mixing method, for example, excessive air or the like is injected into the entangling nozzle. It is necessary to replace the fiber arrangement and mix the fibers, and in this process, the yarn may be subjected to unnecessary rubbing, which may cause single fiber breakage. In particular, in the case of the present invention, the single fibers are crimped to develop bulkiness and stretchability in the fabric. May cause pilling. On the other hand, in the case of the mixed spun yarn preferably used in the present invention, the latent crimped yarn can be obtained without such concerns, and the quality of the fabric is also excellent.

When such a spinning and mixing method is used, in the present invention, it is preferable to use a spinneret in which the diameter of the ejection holes formed in the ejection plate positioned most downstream of the spinneret is varied for each hole. When polymer is discharged from such a nozzle, the flow rate of polymer flowing into each hole is adjusted according to the diameter of the discharge hole so that the pressure loss during discharge is the same for all holes. Fibers can be manufactured with the same spinneret. In this spinneret, the pressure loss is calculated based on the polymer flow rate per discharge hole corresponding to each fiber diameter and the viscosity of the polymer used, and the combination of discharge hole diameters is determined so that the pressure loss is the same for all discharge holes. It is possible to easily and precisely control the fiber diameter without using a special spinneret technique.

At this time, it is preferable that all the ejection holes formed in the ejection plate are round holes. By setting the shape of the discharge hole as described above, it is possible to control the irregularity of all the single fibers constituting the yarn bundle to be low, so that the single fibers of two or more types of fibers can be uniformly dispersed in the yarn bundle. It becomes possible.

In order to obtain the latently crimped yarn of the present invention using the spinneret as described above, it is possible to precisely control the distance between the center of gravity points in the cross section of the single fiber for each single fiber. -208313 and JP-A-2012-136804, a method using a distribution plate is preferably used. In this case, even if the discharge amount changes for each discharge hole, there is no decrease in the distance between the centers of gravity, which causes whitening of the fabric due to friction or impact, exposure of the core component that causes fluff, and deterioration of crimp development. , the eccentric core-sheath composite cross-section required in the present invention can be stably manufactured.

In the method using such distribution plates, the cross-sectional form of the single fibers can be controlled by arranging the distribution holes in the final distribution plate, which is installed most downstream among the plurality of distribution plates. That is, the cross-sectional shape can be controlled by the arrangement of the distribution holes of the polymer A forming the core component and the polymer B forming the sheath component. Specifically, as exemplified in FIG. 5, a distribution hole 5 of the polymer B forming the sheath component is arranged so as to surround the distribution hole 5-(a) of the polymer A forming the core component in the eccentric core-sheath type composite cross section. By arranging -(b), it is possible to form the eccentric core-sheath composite cross section required in the present invention. Here, by adjusting the arrangement and number of distribution holes forming the core and sheath components and changing the discharge rate of the polymer per distribution hole, the cross-sectional shape such as the thickness of the sheath component can be adjusted. Thus, it is possible to stably form an eccentric core-sheath composite cross section without defects even when the amount is changed.

Furthermore, in order to achieve the thin eccentric core-sheath cross section that is preferably used in the present invention, the distribution holes 5-(a) forming the core component in the eccentric core-sheath composite cross section are arranged along the outline of the single fiber, It is preferable to dispose the component distribution holes 5-(b) so as to thinly surround it. When a fiber is produced using a distribution plate with such a distribution hole arrangement, as illustrated in FIG. 6, a thin-skinned eccentric core-sheath composite yarn in which a part of the sheath component in the cross section of the single fiber is a uniform thin skin. is obtained. In the thin-skinned eccentric core-sheath yarn, the ratio S/D of the minimum thickness S of the sheath component covering the core component and the fiber diameter D of the single fiber is 0.01 to 0.10. It is particularly preferable that the peripheral length portion (S ratio) having a thickness within 1.05 times the minimum thickness S occupies 30% or more of the total peripheral length of the cross section of the single fiber. By setting it to such a range, it is possible to set the distance between the center-of-gravity points, which affects crimping, to be longer, and obtain a latently crimped yarn having excellent bulkiness and flexible elongation characteristics, which are the objects of the present invention. of.

In the thin-skin eccentric core-sheath cross section as described above, the number of distribution holes 6-(b) of the polymer B forming the thin skin is preferably 6 or more from the viewpoint of complete coverage of the core component. In addition, the S/D and the length of the minimum thickness can be controlled by adjusting the number of the distribution holes 6-(b) that form the thin skin and the discharge amount of the polymer around the distribution holes. It is possible.

Further, in the case of the above-described thin-skinned eccentric core-sheath cross-section, all the constituent single fiber cross-sections completely cover the A component with the B component as shown in FIG. It is possible to suppress the bending of the ejected polymer (kneeing phenomenon) that occurs because of the above. This is because the presence of the sheath component causes a force in the direction opposite to the bending direction of the polymer flow, resulting in a force in the direction perpendicular to the spinning line caused by the difference in flow velocity between the two types of polymers during ejection from the spinneret. can be suppressed. Such a phenomenon (suppression of extruded polymer bending) is a useful technical feature for stably producing a fiber in which two or more types of single fibers having different fiber diameters are mixed by a spinning mixed fiber method. This finding, which was obtained at the end of the study by the inventors, has led to the achievement of a latent crimped yarn that could not be achieved with the prior art.

In the spun mixed fiber adopted in the present invention, the discharge line bending is suppressed, so that the arrangement of the discharge holes of each single fiber can be designed with a high degree of freedom. It is also possible to control fabric properties such as stretchability.

For example, when monofilaments having different fiber diameters are arranged in a staggered pattern as shown in FIG. 7-(a), the monofilaments are well dispersed in the latently crimped yarn. For this reason, each of the single fibers independently crimps, so that a soft and comfortable feeling of resilience with bulkiness and stretchability due to the crimped structure can be obtained. In addition, if the single fibers having different fiber diameters are grouped and arranged as shown in FIG. The crimped structure is locally meshed to form a crimped structure having converged portions, and the converged portions provide a stretch material with elasticity.

In addition, by suppressing the bending of the discharge line, interference between single fibers on the spinning line can be suppressed, and the number of discharge holes per spinneret can be increased. It enables the improvement of

When melt spinning is selected for the production of the latently crimped yarn of the present invention, the polymer used for the core component and the sheath component is preferably a fiber-forming thermoplastic polymer, such as polyethylene terephthalate or its copolymer, polyethylene Melt moldable polymers such as naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, polypropylene, polyolefins, polycarbonates, polyacrylates, polyamides, polylactic acid, thermoplastic polyurethanes, and the like. In particular, polycondensation polymers represented by polyesters and polyamides have high melting points and are more preferable. When the melting point of the polymer is 165° C. or higher, the heat resistance is good, which is more preferable.

In addition, various additives such as inorganic substances such as titanium oxide, silica, and barium oxide, carbon black, colorants such as dyes and pigments, flame retardants, fluorescent brighteners, antioxidants, and ultraviolet absorbers may be added to the above polymers. Agents may be included in the polymer.

Regarding the combination of polymers used in the latently crimped yarn of the present invention, the core and sheath components may be selected according to the intended use. It is preferable to use a combination that produces a difference. For example, by changing the molecular weight of the polymer described above, the A component in 5-(a) of FIG. 5 is a high molecular weight polymer, and the B component is a low molecular weight polymer, or one is a homopolymer and the other is a copolymer can also Also, for combinations with different polymer compositions, for example, component A/component B is preferably polybutylene terephthalate/polyethylene terephthalate, polytrimethylene terephthalate/polyethylene terephthalate, thermoplastic polyurethane/polyethylene terephthalate, or polytrimethylene terephthalate/polybutylene terephthalate. Examples include:

The spinning temperature is preferably a temperature at which, of the two or more types of polymers used in the latently crimped yarn, mainly the high-melting-point or high-viscosity polymer exhibits fluidity. Although the temperature at which this fluidity is exhibited varies depending on the molecular weight, the melting point of the polymer serves as a guideline, and may be set at the melting point plus 60° C. or lower. If it is less than this, the polymer will not be thermally decomposed in the spinning head or the spinning pack, and unnecessary deterioration of the polymer will be suppressed.

When spinning the latently crimped yarn of the present invention, the discharge rate can be stably discharged in a range of 0.1 g/min/hole to 20.0 g/min/hole per discharge hole. It is preferable to determine from the range according to the desired fiber diameter, taking into consideration the winding conditions, the draw ratio, and the like.

Further, in the present invention, it is preferable to set the discharge amounts of the core component and the sheath component so that the area ratio fc of the core component to the cross section of the single fiber is 30 to 70%. By setting the area ratio of the core component within this range, it is possible to reduce the difference in elongational deformation between the polymers in the spinning line, and to obtain a good quality yarn with small yarn diameter unevenness in the fiber axis direction.

The composite polymer flow, which is discharged while the discharge rate and cross section are precisely controlled by the composite spinneret as described above, is cooled and solidified by the cooling air whose speed and temperature are kept constant. The speed and temperature of the cooling air may be determined in consideration of the cooling efficiency of the yarn and the stabilization of the atmosphere at the solidification point. When considering spinning mixed fibers, the degree of deflection on the spinning line varies depending on the type of single fibers that make up the latent crimped yarn. It is preferable to determine the cooling method in consideration of such factors as to prevent interference.

The cooled and solidified threads are bundled at the same time and oiled. Here, each single fiber diffuses into the latently crimped yarn when it is bundled. are preferably bundled at the same time. As for the oil to be used, the lubricating method, adhesion amount, and type may be determined in consideration of the winding conditions, advanced processing, process passability, and the like. Furthermore, in order to promote uniform adhesion of the oil agent, an interlace nozzle or the like may be used to impart a slight degree of entanglement that does not impair the object of the present invention.

The yarn to which the oil agent has been applied becomes a latently crimped yarn by being taken up by a roller with a specified peripheral speed. Here, the take-up speed may be determined from the discharge amount, the target fiber diameter, the high-order processing process, etc., but in order to stably produce the latently crimped yarn of the present invention, it is in the range of 100 to 7000 m / min. It is preferable to From the viewpoint of achieving high orientation and improving mechanical properties, the film may be stretched after being once wound up, or may be stretched continuously without being once wound up.

As for the drawing conditions, for example, in a drawing machine consisting of a pair or more of rollers, in the case of a fiber made of a thermoplastic polymer that can be melt spun in general, a first roller set at a temperature higher than the glass transition temperature and lower than the melting point is used. Due to the peripheral speed ratio of the second roller corresponding to the crystallization temperature, the fiber is naturally stretched in the fiber axis direction, heat-set and wound. In the case of a polymer that does not show glass transition, the dynamic viscoelasticity measurement (tan δ) of the composite fiber is performed, and a temperature equal to or higher than the peak temperature on the high temperature side of the obtained tan δ is selected as the preheating temperature. Here, from the viewpoint of increasing the draw ratio and improving the mechanical properties, it is also a suitable means to apply this drawing step in multiple stages.

As described above, the method for producing the latently crimped yarn of the present invention has been described based on the general melt spinning method, but it goes without saying that it can also be produced by the meltblown method and the spunbond method. It is also possible to manufacture by a solution spinning method such as a formula.

The latently crimped yarn of the present invention produced as described above is made into a fiber product such as a woven or knitted fabric, and then subjected to a heat treatment to develop crimps in single fibers, thereby exhibiting the effects of the present invention.

At this time, from the viewpoint of actualizing the crimp expression of each single fiber, the heat treatment temperature is based on the Tg of the polymer having the higher glass transition temperature (Tg) among the two or more types of polymers used in the latently crimped yarn. , Tg+10 to Tg+100°C.

Furthermore, in the heat treatment step, it is preferable to apply a relax heat treatment in which the heat treatment is performed in a state in which tension is not applied to the yarn bundle in order to make the single fiber crimped well.

In the present invention, by setting the heat treatment conditions as described above, all the single fibers in the yarn bundle can be satisfactorily crimped, and a suitable yarn form including many interfiber voids between the desired yarn bundles can be expressed. of.

The latently crimped yarn of the present invention will be specifically described below with reference to examples. Examples and comparative examples were evaluated as follows.

(1) Total Fineness of Yarn Bundle The weight of 100 m of fiber to be evaluated was measured and multiplied by 100 to calculate the fineness. This was repeated 10 times, and the fineness was obtained by rounding off the simple average value to the second decimal place.

(2) Fiber strength and elongation at break A tensile tester ("TENSILON" UCT-100 manufactured by Orientec) under constant speed elongation conditions shown in JIS L1013 (2010) 8.5.1 standard time test It was measured. At this time, the gripping distance was 20 cm, the pulling speed was 20 cm/min, and the number of tests was 10. The elongation at break was obtained from the elongation at the point showing the maximum strength in the SS curve.

(3) Fiber diameter and median fiber diameter ratio (Dmax/Dmin)
The latent crimped yarn is embedded in an embedding agent such as epoxy resin, and all single fibers are observed with a VE-7800 scanning electron microscope (SEM) made by Keyence at a magnification that allows 10 or more single fibers to be observed. I took a picture of. In each photographed image, the cross-sectional area Af of the single fiber is measured using the image analysis software "WinROOF2015" manufactured by Mitani Shoji Co., Ltd., and the diameter of the perfect circle having the same area as this area Af is measured in μm. The fiber diameter was calculated by rounding off to the second decimal place. All the single fibers that make up the latent crimped yarn are subjected to the above measurements, and the fiber diameter distribution shown in FIG. 4 is created from the results. The center-to-centroid distance, which is the most abundant peak value in the single fiber group, was determined. Based on this result, the ratio of the distance between the center of gravity points (Dmax/Dmin) was calculated using the maximum (Dmax) and the minimum (Dmin) between the center of gravity points among the latent crimped yarns.

(4) Adjacent filament group ratio In the same manner as the fiber diameter described above, all single fiber cross sections of the latent crimped yarn are photographed two-dimensionally, and based on the results of classification by fiber diameter, randomly selected from the image The number of single fibers constituting adjacent filament groups was counted for each single type of extracted single fiber. Based on this measurement result, the adjacent filament group ratio=(the number of single fibers constituting the adjacent filament group)/(the total number of single fibers of interest)×100 (%) was calculated. The above measurements were carried out at 10 or more points of the latently crimped yarn, and the adjacent filament group ratio of the yarn bundle was evaluated by rounding off the simple number average of the measurement results to the first decimal place.

(5) Irregularity In the same manner as for the fiber diameter described above, the single fiber cross section is photographed two-dimensionally, and the circumscribed circle diameter corresponding to the diameter of the circumscribed circle diameter of the single fiber and the diameter of the perfect circle inscribed in the single fiber The inscribed circle diameter was measured. From these results, the degree of irregularity was calculated as follows: diameter of circumscribed circle/diameter of inscribed circle, and calculated to the third decimal place. The above measurements were performed on 10 single fibers randomly extracted from the image, and the irregularity was evaluated by rounding off the simple number average of the measurement results to the third decimal place.

(6) Area ratio fc of the core component in the single fiber cross section and fc variation In the same manner as for the fiber diameter described above, the single fiber cross section is two-dimensionally photographed, and from the photographed image, image analysis software manufactured by Mitani Shoji Co., Ltd. Using "WinROOF2015", the cross-sectional area Af of the single fiber and the area Ac of the core component were measured in μm ² . From these results, fc was calculated by rounding off the value calculated by fc=Ac/Af×100 (%) to the second decimal place. The above measurements were performed for all the single fibers constituting the latent crimped yarn, and based on the measurement results, (fcCV%) = (standard deviation of fc/average of fc) x 100 (%) was calculated. Then, the fc variation was evaluated with the value rounded off to the second decimal place.

(7) Evaluation of bulkiness of latent crimped yarn (width of yarn bundle)
The bulkiness was evaluated by measuring the width of the yarn bundle after boiling water treatment of the latently crimped yarn.

First, the produced latently crimped yarn was deskeined and immersed in boiling water under substantially no load for 15 minutes. After sufficiently drying the treated thread, it was attached to a slide glass with an adhesive or the like while a load of 0.2 mg/dtex was applied. Ten treated threads were attached in parallel on the same slide glass by the above method without overlapping, and a cover glass was covered so as to cover all the attached treated threads. Then, a weight is placed on the cover glass such that the mass of the cover glass is 0.25 mg/dtex, and the distance between the upper surface of the slide glass and the lower surface of the cover glass after 30 seconds is measured using a vernier caliper. was measured to the first decimal place. The above measurements were performed on five different samples, and the bulkiness was evaluated by the yarn bundle width obtained by rounding off the simple number average of the measurement results to the second decimal place.

(8) Fabric evaluation (bulkiness, stretchability)
Latent crimped yarns are used for the weft and warp yarns to produce a plain weave with a weft density of 90 / inch, refine at 80 ° C for 20 minutes, relax at 120 ° C for 20 minutes, and then heat to 180 ° C. 1 minute mid-set.

The fabric samples prepared above were examined by 10 skilled workers, and the bulkiness of the fabric (determined by ◎, ○, ×) and the elongation when stretched in the weft direction were evaluated by the feel of the fabric when the fabric was deformed. The stretchability was evaluated (determined by ⊚, ◯, and ×).

For bulkiness and stretchability, ◎ is 5 points, ○ is 2 points, × is 0 points, ◎ when the total score of 10 people is 30 points or more, ○ when 10 points to 29 points, 9 points or less Time x.

Example 1
Polybutylene terephthalate (PBT) with a melt viscosity of 160 Pa·s was used as the core component of all single fibers constituting the latently crimped yarn, and polyethylene terephthalate (PET1) with a melt viscosity of 30 Pa·s was used as the sheath component.

In Example 1, a distribution plate having distribution holes illustrated in FIG. 6 was used, and a spinneret incorporating a discharge plate having two types of discharge holes with different diameters was used. After the polymers were individually melted, they were metered by a pump so that the core/sheath discharge rate ratio was 50/50, introduced into the spinneret, and discharged at a spinning temperature of 280°C.

The distribution plate used in Example 1 had a composite cross section ( 2). All the holes are circular (irregularity: 1.00), with 36 holes each having a diameter of 0.18 and 0.23 mm. A spinneret with a houndstooth hole arrangement as shown in FIG. 7-(a) was used, in which discharge holes with a small hole diameter corresponding to the large fiber diameter and discharge holes with a large hole diameter corresponding to the large fiber diameter were alternately arranged.

After cooling, the discharged composite polymer stream was oiled, wound up at a speed of 1000 m/min, and an undrawn yarn of 170 dtex-72 filaments was collected.

The distribution plate shown in FIG. 6 is used to precisely control the flow of the composite polymer during discharge, so that the bending of the flow of the discharged polymer observed directly below the nozzle surface is suppressed to an extremely small value, resulting in excellent discharge stability. rice field.

The wound undrawn yarn was drawn 3.0 times between rollers heated to 70° C. and 130° C. at a drawing speed of 600/min to obtain a latent crimped yarn of the present invention of 56 dtex-72 filaments.

The resulting latently crimped yarn had a strength of 3.3 cN/dtex and an elongation of 33%, which were sufficient for practical use. was 0. Further, when the cross section of the yarn bundle was observed, the yarn bundle contained two types of single fibers with different fiber diameters. Dmax/Dmin) was 1.57. The adjacent filament group ratio was 36%, and the single fibers having a fineness difference that could sufficiently exhibit the effect of eliminating the single fibers due to the difference in crimp configuration were well dispersed within the yarn bundle.

Therefore, the yarn width after the boiling water treatment was 855 μm, and the two types of well-dispersed single fibers formed good crimps, resulting in excellent bulkiness.

When the latently crimped yarn is used as a fabric and heat-treated, single fibers of different sizes are uniformly dispersed in the yarn bundle and crimps are developed. By having a feeling of repulsion against compression in the direction, there was swelling, and it had a repulsion feeling when compressed, which was not conventional (bulkyness: ⊚). Furthermore, the single fibers formed crimps individually, so that the fabric was flexible and stretched well (stretchability: ⊚). Table 1 shows the results.

Examples 2 and 3
In Examples 2 and 3, latently crimped yarns of the present invention were obtained in the same manner as in Example 1, except that the arrangement of the ejection holes was changed as shown in Table 1.

The core-sheath discharge holes are arranged such that a group of discharge holes having a large diameter corresponding to the diameter of the thick fiber is surrounded by a group of discharge holes having a diameter corresponding to the diameter of the fine fiber, as illustrated in FIG. 7-(c). As shown in FIG. 7-(b), the grouping arrangement is such that ejection hole groups corresponding to each fiber diameter are arranged separately.

The evaluation results of the latently crimped yarns of Examples 2 and 3 are shown in Table 1. In both cases, similarly to Example 1, the bending of the discharged polymer flow observed directly below the nozzle surface was extremely small. It was excellent in ejection stability.

In the latently crimped yarn of Example 2, since the discharge hole arrangement is the core-sheath arrangement, although the same type of single fibers were slightly unevenly distributed in the center of the yarn bundle where the single fibers are difficult to diffuse, the adjacent filament group ratio was It was 59%, and the dispersibility of single fibers in the latent crimped yarn was good.

When this is heat-treated, it is excellent in bulkiness due to the effect of eliminating well-dispersed monofilaments, even though it is partially bundled at the center of the yarn bundle and crimps appear. It had a feeling of fullness and an elongation property with a feeling of resilience.

On the other hand, in the latently crimped yarn of Example 3, the discharge holes are arranged in groups, so that the single fibers of the same type are dispersed in the yarn bundle in a state of being appropriately close to each other, and some of them are converged. However, crimps were developed, so the bulkiness was slightly inferior, but it was at a level without problems.

When the fabric is made into a fabric and subjected to heat treatment or the like, it has a suitable bulging feeling, but also has a firm and stretchable property because the converging portion forms a large crimp. Table 1 shows the results.

Example 4
In Example 4, the latently crimped yarn of the present invention was prepared in the same manner as in Example 1, except that the ejection holes of the ejection plate used in Example 1 were made oval with the same area, and the irregularity was changed to 1.20. got The discharge hole was designed so that the longitudinal direction of the discharge hole coincided with the line connecting the center of the single fiber and the center of gravity of the core component.

In Example 4, since the degree of irregularity of the ejection holes was increased, the bending of the ejected polymer flow just below the nozzle surface was suppressed, and the ejection stability was excellent.

In the latently crimped yarn of Example 4, the measured irregularity of the single fibers was 1.15. As a result, although the dispersibility in the single fiber yarn bundle was low, when it was made into a fabric, it had a suitable bulging feeling and a unique surface feel due to the cross-sectional deformation.

Example 5
In Example 5, a latently crimped yarn of the present invention was obtained in the same manner as in Example 1, except that the core/sheath polymer discharge ratio was changed to 60/40.

In Example 5, since the ejection speed of the high-viscosity core polymer was improved, the flow bending of the ejected polymer directly below the nozzle surface was suppressed, and the ejection stability was particularly excellent.

In the latently crimped yarn of Example 5, the adjacent filament group ratio was small, and the single fibers in the yarn bundle were well dispersed. In addition, due to the change in pressure loss in the ejection plate accompanying the increase in the ejection ratio of the core polymer, the ejection ratio of the core/sheath polymer of the single fiber changes for each fiber diameter. The variation in fc was large.

For this reason, in the latently crimped yarn of Example 5, the single fibers having a fine fiber diameter with a low ratio of the core polymer were restrained from crimping due to the peripheral restraint, so that the effect of removing the single fibers from each other was reduced. The bulkiness was at a level without problems, and when made into a fabric, it had a suitable swelling feeling and elongation properties.

Examples 6 and 7
In Examples 6 and 7, latently crimped yarns of the present invention were obtained in the same manner as in Example 1, except that the ejection hole diameter of the ejection plate was changed so that the median fiber diameter was as shown in Table 1.

In Examples 6 and 7, although the bending degree of the discharged polymer flow just below the nozzle surface changed according to the change in the fiber diameter of the single fiber, in both cases, the composite polymer flow was discharged while being precisely controlled. It was excellent in ejection stability.

In addition, in the latently crimped yarns of Examples 6 and 7, the adjacent filament group ratio, which indicates the degree of dispersion of the single fibers in the yarn bundle, changes depending on the fiber diameter structure of the constituent single fibers. In this case as well, the dispersibility was good because the two types of single fibers were bundled together by the spinning and mixing method.

The latently crimped yarn of Example 6 increased the fiber diameter ratio between the single fibers, thereby increasing the difference in crimp configuration. . Furthermore, since the single fibers having a large fiber diameter form large-sized crimps, the fabric has a good swelling feeling and also has a suitable repulsive feeling when stretched.

On the other hand, the latently crimped yarn of Example 7 had a small fiber diameter ratio between the single fibers, and although the effect of eliminating the single fibers due to the difference in crimp configuration was slightly inferior, the bulkiness was at a satisfactory level. When it was made into a fabric, it had a feeling of swelling, and furthermore, it exhibited a smooth surface quality due to the small deviation of the crimp size between the single fibers.

Example 8
In Example 8, two types of ejection holes (hole diameters: 0.18 mm, 0.23 mm, all ejection hole shapes with an irregularity of 1.00) similar to those of the ejection plate of Example 1 were drilled for 12H each. Using. The holes were arranged in a zigzag arrangement in which ejection holes with different diameters were alternately arranged. The combination of polymers constituting the latent crimped yarn, the spinning temperature, and the polymer ejection ratio were the same as in Example 1. The composite polymer stream was cooled and solidified, then oiled, and wound at a spinning speed of 1000 m/min to obtain a 170 dtex- An undrawn fiber of 24 filaments was collected.

In Example 8, since the fiber diameter was increased, the bending of the discharged polymer flow observed directly below the nozzle surface was extremely small, and the discharge stability was excellent.

By drawing the wound undrawn fiber under the same conditions as in Example 1, a 56 dtex-24 filament latently crimped yarn of the present invention was obtained.

In the latently crimped yarn of Example 8, the overall fiber diameter increased and the number of filaments decreased, resulting in a slightly higher adjacent filament group ratio. Since it is large, the effect of removing between single fibers is increased, and it has excellent bulkiness. When made into a fabric, the yarn bundle contained many voids, and had an excellent feeling of swelling and a slightly high feeling of repulsion.

Examples 9 and 10
In Examples 9 and 10, the polymer was changed as shown in Table 2, the same spinneret as in Example 1 was used, and the spinning conditions were adjusted so that the elongation of the latently crimped yarn obtained in each example was 30 to 40%. and drawing conditions were set to obtain the latently crimped yarn of the present invention.

In Examples 9 and 10, the difference in melt viscosity between the two types of polymers constituting the latent crimped yarn was large, so the bending of the discharged polymer directly under the surface of the spinneret was large. It was excellent for

In the latently crimped yarn of Example 9, by using PPT as a high shrinkage component, the effect of removing single fibers from each other is reduced due to the low Young's modulus of PPT, but the adjacent filament group ratio is low and the number of single fibers is low. Since the dispersibility is good, the bulkiness is high, and when it is made into a fabric, it has a soft touch and good and soft stretchability.

The latent crimped yarn of Example 10 used PET2 (melt viscosity: 290 Pa s) as a high shrinkage component, so that the Young's modulus of the latent crimped yarn was large, and when it was made into a fabric, it had a stiff and stiff fabric texture. . On the other hand, the tension in the spinning process is high, and when the yarn bundle is bundled, the single fibers easily blend together. Since the exclusion effect between the single fibers is increased, the fabric has a good feeling of swelling when made into a fabric. Table 2 shows the results.

Example 11
Example 11 was the same as Example 1, except that a discharge plate was used in which 24H each of discharge holes having three different hole diameters, large, medium and small, were drilled so that the median fiber diameter was as shown in Table 1. to obtain the latently crimped yarn of the present invention. All of the discharge holes are round holes (irregularity: 1.00). A mouthpiece with concentric hole arrangement was used in which a group of discharge holes with a large hole diameter was surrounded by a group of discharge holes with a large hole diameter.

In Example 11, although the degree of bending of the extruded polymer directly below the nozzle surface varied for each ejection hole corresponding to each fiber diameter, in all cases the composite polymer flow was extruded while being precisely controlled, resulting in improved ejection stability. It was excellent.

In the latently crimped yarn of Example 11, all three types of single fibers are well dispersed in the yarn bundle, and the adjacent filament group ratio is extremely small, so the effect of eliminating between single fibers is extremely high and excellent. It had bulkiness. When it is made into a fabric, the single fibers of three different sizes, large, medium and small, are uniformly dispersed in the yarn bundle, so that the yarn bundle contains microscopic voids of various sizes. It had a particularly soft elasticity when crushed.

Example 12
In Example 12, a latently crimped yarn was obtained in the same manner as in Example 1, except that the core/sheath polymer discharge ratio was changed to 70/30.

When the fc variation of the single fiber cross section of the latently crimped yarn of Example 12 was measured, it was as large as 15.3%. Although the expression of crimp was suppressed by the restraint, the yarn bundle had suitable bulkiness. When made into a fabric, the bulkiness and elongation properties were slightly inferior, but they were at a satisfactory level.

Example 13
In Example 13, a latently crimped yarn was obtained in the same manner as in Example 1 except that the ejection hole diameter was changed so that the median fiber diameter was as shown in Table 2.

In the latently crimped yarn of Example 13, although the dispersibility of the single fibers in the yarn bundle was good, the difference in the crimp configuration of the single fibers was excessively expanded, resulting in the inter-fiber gap between the large size crimps. A filament form was obtained in which small-sized crimps were densely packed in the voids. For this reason, although the effect of removing the single fibers was sufficiently small, it was at a level of no problem. Although the bulkiness of the fabric was slightly inferior, it had a suitable feeling of elasticity when crushed and a good elongation property.

Comparative example 1
In Comparative Example 1, a latently crimped yarn was obtained in the same manner as in Example 1, except that a discharge plate having only discharge holes having the same hole diameter was used.

In the latently crimped yarn of Comparative Example 1, since all the single fibers formed crimps of the same size, the single fibers were crimped so as to mesh with each other and converged as a whole, resulting in low bulkiness. . Therefore, when it is made into a fabric, although it has stretchability, it is inferior in bulkiness, and the fabric aimed at by the present invention could not be obtained.

Comparative example 2
In Comparative Example 2, PBT and PET1 used in Example 1 were used. Latent crimp yarns of 36 filaments and 40 dtex-36 filaments were produced in separate steps. These latently crimped yarns were mixed with an interlace nozzle to obtain a latently crimped yarn (56 dtex-72 filaments, center fiber diameter ratio: 1.57, irregularity: 1.02).

In the latently crimped yarn of Comparative Example 2, the dispersibility of the single fibers in the yarn bundle was extremely poor compared to the latently crimped yarn of the present invention, and there were places where the existence probability of the same kind of single fibers was concentrated.

In addition, since the interlace nozzle provides entanglement, the dispersibility of the single fibers in the yarn bundle is improved in some areas at the entangled portions, but compared with Example 1, the dispersibility of the single fibers is insufficient. there were.

For this reason, the effect of removing the single fibers from each other was not sufficiently obtained, and the bulkiness of the fabric was inferior to that of Example 1, and the fabric aimed at by the present invention was not achieved.

Comparative example 3
In Comparative Example 3, a latently crimped yarn was obtained in the same manner as in Example 1, except that the ejection holes of the ejection plate used in Example 1 were made elliptical while maintaining the same area, and the irregularity was changed to 2.40. . The discharge hole was designed so that the longitudinal direction of the discharge hole coincided with the line connecting the center of the single fiber and the center of gravity of the core component.

When the irregularity of the single fiber cross section of the latently crimped yarn of Comparative Example 3 was measured, it was 2.10. was low. Furthermore, when heat treatment is applied, crimps develop while bundling single fibers of the same type, resulting in poor bulkiness. It had a rough surface texture.

a: Gravity center point of A component in cross section of single fibers constituting latent crimped yarn c: Center point of cross section of single fibers constituting latent crimped yarn S: Minimum thickness of B component D: Fiber diameter H _S : Discharge plate Out of the ejection holes, ejection holes H _L for ejecting single fibers with a small fiber diameter: Out of the ejection holes in the ejection plate, ejection holes 3-(a), (b) for ejecting single fibers with a large fiber diameter ): Example of monofilaments having the same fiber diameter that are adjacently connected in the cross section of the latent crimped yarn 3-(c): An example of a group of adjacent filaments in the cross section of the latent crimped yarn 4-(a): Constructing the latent crimped yarn Fiber diameter distribution of single fibers A 4-(b): Central fiber diameter of single fibers A constituting latent crimped yarn 4-(c): Fiber diameter distribution of single fibers B constituting latent crimped yarn 4-(d): Median fiber diameter of single fiber B constituting latent crimped yarn 4-(e): Distribution width of fiber diameter of single fiber A constituting latent crimped yarn 4-(f): Latent winding Distribution width 5-(a) of the fiber diameter of the single fibers B constituting the crimped yarn: Distribution hole 5-(b) of the A component forming the core component among the distribution holes in the final distribution plate: Distribution in the final distribution plate Of the holes, component B distribution hole 6-(a) that forms the sheath component: Of the distribution holes in the final distribution plate, component A distribution hole 6-(b): component B distribution hole 6 that forms the thin skin -(c): Of the distribution holes in the final distribution plate, the distribution holes for the B component other than 6-(b)

Claims (4)

Two or more types of eccentric core-sheath composite fibers with different fiber diameters are dispersed and mixed in the yarn bundle, and the maximum value (Dmax) and the minimum value (Dmin) of the central fiber diameter of the single fibers that make up the yarn bundle. A latently crimped yarn having a ratio (Dmax/Dmin) of 1.20 or more . 2. The latently crimped yarn according to claim 1, wherein all the fibers contained in the yarn bundle have an irregularity of less than 1.20. 3. The latently crimped yarn according to claim 1, wherein all the fibers contained in the yarn bundle have the same area ratio of the core component to the single fiber cross section. A textile product at least partially containing the latently crimped yarn according to any one of claims 1 to 3.

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