KR102254669B1 - Modified cross-section fiber - Google Patents

Abstract

In particular, it is an object of the present invention to provide a modified single-sided fiber that can be divided and used thereby efficiently producing fine composite fibers. The present invention is more than (1) a plurality of pieces of a composite fiber structure comprising a first thermoplastic resin and a second thermoplastic resin having a lower melting point or softening point than the first thermoplastic resin, and (2) the second thermoplastic resin A modified cross-sectional fiber comprising a connector comprising a third thermoplastic resin having a high melting point or softening point, wherein in any fiber cross section, at least two pieces of the composite fiber structure are connected to the modified cross-sectional fiber connected by the connector. About.

Description

Modified cross-section fiber {MODIFIED CROSS-SECTION FIBER}

The present invention relates to a particular modified cross-sectional fiber. More specifically, the present invention relates to a deformed cross-sectional fiber that is excellent in splitting ability and, after being split, its fine conjugate fiber structure can be individually and independently derived as a fine conjugate fiber structure.

Studies on various dividable composite fibers have been conducted so far. For example, in PTL 1, 1 to 30% by weight of an ethylene-vinyl alcohol copolymer having a degree of saponification of 95% or more as a component of a polyolefin-based resin in the dividable composite fiber formed of a polyolefin-based resin. It is suggested that the dividing ability is improved by using a resin containing PTL 2 suggests that a thermoplastic resin containing two components having different heat shrinkage is used to easily divide the resin by taking advantage of the difference in heat shrinkage during heat treatment. However, in both PTL 1 and PTL 2, the fiber after splitting has a single component, the points thermally bonded during forming the non-woven fabric are reduced, and the strength of the non-woven fabric becomes insufficient.

In PTL 3, a single component (A) and component (B) are splittable composite fibers having an alternating cross-sectional structure having a conjugate structure formed of a core component and a sheath component, and a part is even Fibers that exist in the form of a sheath-core composite structure even after division are presented. Accordingly, fibers with a composite structure are partially present after division.

Citation list

Patent literature

PTL 1: JP 2002-088583 A

PTL 2: JP 2006-328628 A

PTL 3: JP 2011-009150 A

However, in the dividable conjugate fiber according to PTL 3, the periphery of the fiber cross section perpendicular to the main axis direction of the dividable conjugate fiber is circular, and the fiber must have a basically large bonding area between component A and component B. Structure, etc., and thus, high external stress, such as a jet of a high-pressure water stream, etc., has to be applied during the dividing, and thus further improvement of the dividing ability is desired.

Accordingly, it is an object of the present invention to provide a deformed single-sided fiber capable of efficiently producing fine conjugated fibers, in particular by being divided and used later.

The inventors have been diligently conducting research continuously in order to solve the above-described problems, and as a result, a modified cross-sectional fiber having a configuration in which at least two composite fiber structures are connected by a connector can achieve the desired object. It was found that there is, and accordingly, the present invention was completed.

In more detail, the present invention has the configurations described below.

[1] (1) a plurality of pieces of a conjugate fiber structure comprising a first thermoplastic resin and a second thermoplastic resin having a lower melting point or softening point than the first thermoplastic resin; And

(2) As a modified cross-section fiber comprising a connected body comprising a third thermoplastic resin having a higher melting point or softening point than the second thermoplastic resin,

In any fiber cross-section, at least two pieces of the composite fiber structure are connected by the connector.

[2] The modified cross-sectional fiber according to [1], wherein the connector further comprises the second thermoplastic resin, and a peripheral portion of the third thermoplastic resin is covered with the second thermoplastic resin. .

[3] The modified cross-sectional fiber according to [1] or [2], wherein the cross-sectional shape of the composite fiber structure is substantially circular or polygonal.

[4] The modified single-sided fiber according to any one of [1] to [3] above, comprising two to six pieces of the composite fiber structure.

[5] The modified single-sided fiber according to any one of [1] to [4] above, wherein the first thermoplastic resin and the third thermoplastic resin are the same resin.

[6] The modified single-sided fiber according to any one of [1] to [5] above, wherein the second thermoplastic resin occupies the surface of the composite fiber structure except for a portion connected to the connector.

[7] The modified single-sided fiber according to any one of [2] to [6] above, wherein the third thermoplastic resin occupies 20% or more of the cross-section of the connecting body.

[8] The molded cross section according to any one of [2] to [7], wherein the second thermoplastic resin included in the connecting body and the second thermoplastic resin included in the composite fiber structure are melted and integrated. fiber.

[9] The three pieces of the composite fiber structure according to any one of [1] to [8] above, arranged at substantially equal intervals around one piece of the composite fiber structure positioned at the center, are located at the center. And a structure in which each piece of the conjugated fiber structure is connected by the connector.

[10] One piece of the composite fiber structure according to any one of [1] to [9] above, wherein the length of the connected portion between the conjugate fiber structure and the connector in an arbitrary fiber cross section of the deformed cross-sectional fiber is In the relationship between the and one piece of the connecting body connected thereto, 65% or less of the length of the periphery of the composite fiber structure, the modified cross-sectional fiber.

The modified single-sided fiber according to the present invention has excellent glossiness and hiding properties of the fiber, and excellent moisture discharging properties. In particular, by using the modified single-sided fiber of the present invention after dividing, fine conjugated fibers can be efficiently produced. Further, a nonwoven fabric having high strength can be obtained by using conjugated fibers derived from the divided, deformed cross-sectional fibers.

1(a) to 1(f) are schematic views of a fiber cross-section perpendicular to the main axis direction of the deformed cross-section fiber according to the present invention.
FIG. 2 is a fluorescence micrograph (magnification: 20) of a fiber cross section perpendicular to the main axis direction of the deformed cross-section fiber obtained in Example 1. FIG.
3 is a SEM photograph (array: 1,000) showing the divided state of the deformed cross-sectional fiber obtained in Example 1.

The invention will be described in more detail below.

The fiber according to the present invention is a modified cross-sectional fiber having a plurality of pieces of a composite fiber structure to be processed into a plurality of pieces of fine composite fibers by being divided.

The modified single-sided fiber according to the present invention comprises a plurality of pieces of a composite fiber structure comprising (1) a first thermoplastic resin and a second thermoplastic resin having a lower melting point or softening point than the first thermoplastic resin, and (2) the first thermoplastic resin. 2 It comprises a connector comprising a third thermoplastic resin having a higher melting point or softening point than the thermoplastic resin, and in any fiber cross section, at least two pieces of the composite fiber structure are connected by the connector.

In the present invention, a cross section perpendicular to the direction of the major axis of the fiber is referred to as a “cross section” or “fiber section”.

The modified shape of the modified cross-sectional fiber is not particularly limited when the fiber has the above-described configuration. However, in order to facilitate understanding of the present invention, examples of cross-sections of the modified cross-sectional fibers of the present invention are shown in Figs. 1(a) to 1(f).

Specific examples of the modified single-sided fibers according to the present invention include modified single-sided fibers 1A, 1B, 1C, 1D, 1E and 1F as shown in Figs. 1(a) to 1(f), respectively. A second thermoplastic resin 12 having a melting point or softening point lower than the melting point or softening point of the first thermoplastic resin 11 and the first thermoplastic resin 11 in any fiber cross section of the modified cross-sectional fibers 1A to 1F. The plurality of pieces of the composite fiber structure 14 are connected by a connecting body 15 comprising a third thermoplastic resin 13 having a melting point or softening point higher than that of the second thermoplastic resin 12 or softening point. In variant cross-sectional fibers, the shape of the fiber cross-section may be mechanically or mechanically symmetrical or asymmetrical.

In Figs. 1(a) to 1(f), the number of conjugated fiber structures 14 is 2 to 4, but the number of conjugated fiber structures is not particularly limited in the present invention, and may be 2 or more. From the point of view of the structure of the spinneret used for the production of deformed cross-sectional fibers and to maintain the deformed cross-sectional structure during spinning, the number of composite fiber structures 14 is preferably 2 to 6, and more It is preferably 3 to 6.

In particular, as shown in Figs. 1(c) and 1(f), three pieces of a composite fiber structure 14 arranged at substantially equal intervals around one piece of a centrally located composite fiber structure Particularly preferred are deformed cross-sectional fibers 1C and 1F having a structure connected to one piece of the composite fiber structure 14 centered by the connector 15, because the fibers easily maintain the deformed shape, This is because the division ability improves.

Further, if the number of conjugated fiber structures 14 is too high, the structure of the deformed cross-sectional fiber becomes complex, and high external stress must be applied during division in many cases.

In the present invention, as the composite fiber structure 14, the first thermoplastic resin 11 is contained as a core component, and the second thermoplastic resin 12 is contained as a covering part, a coated-core composite fiber, or a second thermoplastic resin ( A side-by-side type (parallel type) in which 12) occupies 30% or more of the periphery of the fiber is preferred. When the composite fiber structure 14 is a coated-core composite fiber, the second thermoplastic resin 12 only needs to occupy the periphery of the composite fiber, and the composite fiber may have a concentric shape or an eccentric shape.

Further, the composite fiber structure 14 is preferably substantially circular or polygonal in cross-sectional shape. When the fiber cross section is substantially circular or polygonal, the bonding area may be increased during thermal bonding processing of the first thermoplastic resin 11 and the second thermoplastic resin 12.

The structure of the connector 15 is not particularly limited, and may be formed of only a third thermoplastic resin 13, as shown in FIGS. 1(a) to 1(c), or FIGS. 1(d) to As shown in Fig. 1(f), it may be formed of a third thermoplastic resin 13 and any other thermoplastic resin, for example, a second thermoplastic resin 12. In particular, from the viewpoint of melting and uniting with the composite fiber structure 14, any other thermoplastic resin preferably comprises a second thermoplastic resin.

When the connector 15 is formed of the third thermoplastic resin 13 and any other thermoplastic resin (the second thermoplastic resin 12), the connector 15 is preferably the second thermoplastic resin 12 It has a structure covering the periphery of the third thermoplastic resin 13.

When the connector 15 includes the third thermoplastic resin 13 and the second thermoplastic resin 12, in particular, the connector 15 is the second thermoplastic resin 12 When having a structure covering the circumference, the connector 15 is a structure in which the third thermoplastic resin 13 and the second thermoplastic resin 12 contact on the interface at an arbitrary cross section perpendicular to the main axis direction of the deformed cross-section fiber. . In the cross section of the connector 15, the third thermoplastic resin 13 preferably occupies 20% or more. The proportion of the third thermoplastic resin 13 in the cross section of the connector 15 is more preferably 60 to 100%, and most preferably 80 to 100%. When the ratio is in the above-described range, the dividing ability between the composite fiber structure 14 and the connector 15 is improved, and accordingly, the deformed cross-sectional fibers 1A to 1F can be easily divided.

When the connector 15 includes the third thermoplastic resin 13 and the second thermoplastic resin 12, the second thermoplastic resin 12 included in the composite fiber structure 14, and the connector 15 The included second thermoplastic resin 12 is preferably melted and integrated on its contact surface. When the composite fiber structure 14 and the connector 15 are melted and integrated on the contact surface, the processing stability during spinning becomes satisfactory.

The length of the connecting body 15 is not particularly limited. For example, in the case of a fiber having a fineness of 5 to 30 dtex in an unstretched fiber, the length is in the range of 2 to 10 micrometers, taking into account the spinning ability and maintenance of the shaped cross-sectional shape. , And preferably in the range of 4 to 8 micrometers. When the length is in the above-described range, the processing stability during spinning becomes satisfactory, and thus such a length is preferred.

Further, in the present invention, when the resins on the contact surface between the composite fiber structure 14 and the connector 15 are melted and integrated, two composite fiber structures 14 in a cross section perpendicular to the main axis direction of the deformed cross-section fiber. The length of the third thermoplastic resin 13 connecting them is defined as the length of the connecting body in the direction toward the composite fiber structure 14. Also, in the connector, the direction towards the composite fiber structure may sometimes be referred to below as the "longitudinal direction of the connector".

It is preferable that the bonding area between the composite fiber structure 14 and the connector 15 is smaller than from the viewpoint of the dividing ability. Since the bonding area between the composite fiber structure 14 and the connector 15 is smaller, only a smaller external stress is desired while dividing, and the dividing is facilitated.

In the cross section of the deformed cross-section fiber, the bonding length X between the composite fiber structure 14 and the connector 15 (see FIGS. 1(a) and 1(d)) is preferably a direction perpendicular to the longitudinal direction of the connector. In the maximum width Y of the composite fiber structure 14 (refer to Figs. 1(a) and 1(d)) (when the composite fiber structure is annular, its diameter) is less than or equal to. When the bonding length X is less than or equal to the maximum width Y of the composite fiber structure, division becomes easy. From the viewpoint of processing stability and ease of dividing ability during spinning, the bonding length X is preferably in the range of 50 to 95% of the maximum width Y of the composite fiber structure in the direction perpendicular to the longitudinal direction of the connecting body, and more preferably, It is in the range of 60 to 90%.

Further, in the present invention, in the relationship between one piece of the composite fiber structure 14 and one piece of the connector 15 connected thereto, the connected portion between the composite fiber structure 14 and the connector 15 in the fiber cross section The length Z of (see Figs. 1(a) and 1(d)) is preferably not more than 65% of the length of the periphery of the composite fiber structure 14, and more preferably 50 to 15% thereof. When the length Z of the connected portion is in the above-described range, division becomes easy, and thus, such a length is preferable. Here, the connected part means a contact part between the composite fiber structure 14 and the connecting body 15. In addition, the length Z of the connected part means the length of the contact part between the composite fiber structure 14 and the connector 15 in the fiber cross section. As shown in Fig.1(d), when the connecting body is formed of the third thermoplastic resin 13 and another thermoplastic resin, for example, the second thermoplastic resin 12, the length Z of the connected portion is the composite fiber structure (14) means the length of the connected part, assuming that it retains its original structure. The length of the periphery of the composite fiber structure 14 only refers to the estimated length when the composite fiber structure 14 is visible.

In the present invention, for all of the first thermoplastic resin, the second thermoplastic resin and the third thermoplastic resin, different resins may be used, but the third thermoplastic resin is preferably the first thermoplastic resin from the viewpoint of improving the processing ability and the dividing ability. Same as Suzy.

The second thermoplastic resin 12 has a melting point or softening point lower than the melting point or softening point of the first thermoplastic resin 11 as described above. Specifically, a resin having a melting point or softening point 15 to 150°C lower than the melting point of the first thermoplastic resin 11 is preferably used, and having a melting point or softening point 30 to 130°C lower than the melting point of the first thermoplastic resin 11 Resins are more preferably used. When the melting point or softening point is in the above-described temperature range, thermobonding processing using a difference in the melting point or softening point may be performed. In the present invention, the thermoplastic resin to be used is generally selected on the basis of the temperature of the melting point, but the softening point will be adopted for a resin that does not have a melting point.

The first to third thermoplastic resins used for the modified single-sided fibers according to the present invention are not particularly limited as long as these meet the requirements for a melting point or a softening point. Fiber-formable resins are preferably used, such as polyester resins; Polyamide resin (nylon); Polyolefin-based resins; ABS resin; AS resin; Polystyrene resin; Acrylic resin; Polycarbonate; Polyphenylene ether; Polyacetal; Polyphenylene sulfide; Polyetheretherketone; Liquid crystal polymer; Fluorocarbon resins; Urethane resin; And elastomers, and polyolefin resins or polyester resins are more preferably used. In addition, the thermoplastic resin can also be produced by combining a plurality of resins described above.

Specific examples of polyolefin-based resins that can be used for the modified single-sided fibers according to the present invention are described below, but the polyolefin-based resin is not particularly limited to these.

For example, polyethylene, polypropylene, polybutene-1, polyhexene-1, polyoctene-1, poly(4-methylpentene-1), polymethylpentene, 1,2-polybutadiene, 1,4-poly Butadiene, etc. can be used. In addition, as a copolymer component, a small amount of α-olefin, for example, ethylene, propylene, butene-1, hexene-1, octene-1, or 4-methylpentene-1 is a monomer in which α-olefin forms a homopolymer. It may be contained in the above-described homopolymer under conditions that are components other than those. In addition, small amounts of other ethylenically unsaturated monomers such as butadiene, isoprene, 1,3-pentadiene, styrene and α-methylstyrene may be contained as copolymer components. In addition, two or more classes of polyolefin-based resins may be mixed and used.

As the resin, a polyolefin-based resin polymerized using a general Ziegler-Natta catalyst, as well as a polyolefin-based resin polymerized using a metallocene catalyst, and a copolymer thereof may be preferably used. . In addition, the melt mass flow rate (hereinafter, abbreviated as MFR) of the polyolefin-based resin that can be preferably used is not particularly limited when the MFR is in a range in which fibers can be spun, It is preferably in the range of 1 to 100 g/10 min, and more preferably in the range of 5 to 70 g/10 min.

The polyolefin-based resin that can be used for the modified single-sided fibers in the present invention preferably comprises at least one class of polyolefin-based resins selected from the group of copolymers containing polyethylene, polypropylene and propylene as main components. Specific examples thereof include high-density polyethylene, linear low-density polyethylene, low-density polyethylene, polypropylene (propylene homopolymer) as the main component, ethylene-propylene copolymer containing propylene, and ethylene-propylene-butene-1 copolymer containing propylene as the main component. Includes. The term "copolymer containing propylene as a main component" means a copolymer in which propylene units are contained in the largest amount among the copolymer components forming the copolymer.

Physical properties of polyolefins different from the MFR described above, such as Q value (number of weight average molecular weight/number of average molecular weights), Rockwell hardness, and number of branched methyl chains, are characterized by the physical properties. There is no particular limitation in the case of satisfying the requirements according to the present invention.

Polyester-based resins that can be used for the modified single-sided fibers according to the invention can be obtained by polycondensation of diols and dicarboxylic acids. Specific examples of dicarboxylic acids used for polycondensation for polyester resins include terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, adipic acid and sebacic acid. Specific examples of diols used include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol and 1,4-cyclohexanedimethanol.

As the polyester-based resin that can be used in the modified single-sided fiber of the present invention, polyethylene terephthalate, polypropylene terephthalate or polybutylene terephthalate may be preferably used. In addition, aliphatic polyesters can be used in addition to aromatic polyesters. Specific examples of preferred aliphatic polyesters include polylactic acid and polybutylene succinate. The polyester resin may be a homopolymer as well as a copolymerized polyester (copolyester). Sometimes, as the copolymerization component, a dicarboxylic acid component, such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid, a diol component, such as diethylene glycol and neopentyl glycol, Or optical isomers such as L-lactic acid can be used. Specific examples of such copolymers include polybutylene adipate terephthalate. In addition, two or more classes of polyester resins may be mixed and used. When the material cost and thermal stability of the obtained fiber are considered, as the resin used for the present composite fiber, an unmodified polymer formed only of polyethylene terephthalate is most preferred.

When additives such as antioxidants, light stabilizers, ultraviolet light absorbers, neutralizers, nucleating agents, epoxy stabilizers, lubricants, antibacterial agents, flame retardants, antistatic agents, pigments and plasticizers are required in the thermoplastic resin, the present invention It may be added as appropriate within a range that does not adversely affect the advantageous effect of.

An example of a combination of resins constituting the modified single-sided fiber according to the present invention is described below, but the combinations are not particularly limited thereto. The first thermoplastic resin and the third thermoplastic resin are preferably the same in consideration of processing capability. Further, when the connector includes the second thermoplastic resin and the third thermoplastic resin, the second thermoplastic resin included in the composite fiber structure and the second thermoplastic resin included in the connector are the same resin.

A specific example of a combination of (first thermoplastic resin and third thermoplastic resin)-(second thermoplastic resin) is, under the condition that the first thermoplastic resin and the third thermoplastic resin have a higher melting point compared to the second thermoplastic resin, Polypropylene-high density polyethylene, polypropylene-low density polyethylene, polypropylene-linear low density polyethylene, ethylene-propylene copolymer-high density polyethylene, ethylene-propylene copolymer-low density polyethylene, ethylene-propylene copolymer-linear low density polyethylene, polyethylene terephthalate -Ethylene-propylene copolymer, polyethylene terephthalate-polypropylene, polyethylene terephthalate-high density polyethylene, polyethylene terephthalate-linear low density polyethylene, polyethylene terephthalate-low density polyethylene, polybutylene terephthalate-high density polyethylene, polybutylene terephthalate -Low density polyethylene, polybutylene terephthalate-linear low density polyethylene, polybutylene terephthalate-polypropylene, polybutylene terephthalate-ethylene-propylene copolymer, and polybutylene terephthalate-polyethylene terephthalate. Among the combinations, more preferred combinations are polypropylene-high density polyethylene or polyethylene terephthalate-high density polyethylene.

When all of the first thermoplastic resin, the second thermoplastic resin and the third thermoplastic resin are different under the condition that the first thermoplastic resin has a higher melting point compared to the second thermoplastic resin, the combination (first thermoplastic resin)-(agent Specific examples of 2 thermoplastic resin)-(third thermoplastic resin) are polypropylene-high density polyethylene-polyethylene terephthalate, polypropylene-linear low-density polyethylene-high-density polyethylene, polypropylene-low-density polyethylene-high-density polyethylene, polypropylene-high-density polyethylene- Ethylene-propylene copolymer, polyethylene terephthalate-high density polyethylene-ethylene-propylene copolymer, polyethylene terephthalate-high density polyethylene-polypropylene, polyethylene terephthalate-low density polyethylene-polypropylene, polyethylene terephthalate-linear low density polyethylene-polypropylene, Polyethylene terephthalate-high density polyethylene-polybutylene terephthalate, polyethylene terephthalate-low density polyethylene-polybutylene terephthalate, polyethylene terephthalate-linear low density polyethylene-polybutylene terephthalate, polyethylene terephthalate-polypropylene-polybutylene Terephthalate, polybutylene terephthalate-high density polyethylene-ethylene-propylene copolymer, polybutylene terephthalate-low density polyethylene-ethylene-propylene copolymer, and polybutylene terephthalate-linear low density polyethylene-ethylene-propylene copolymer. Including, but the combination is not limited thereto.

A specific example of a method for producing a modified single-sided fiber according to the present invention is described below, but the method is not particularly limited thereto. A method for producing a modified single-sided fiber having a melting point 15°C higher than that of the second thermoplastic resin and the first thermoplastic resin and the third thermoplastic resin are the same, in which two classes of polyolefin-based resins having different melting points are combined An example of is described.

Two classes of polyolefin-based resins are processed into fibers by applying a melt spinning method and using spinning protrusions having a specific shape capable of producing deformed cross-sectional fibers. Upon spinning, the fibers are preferably spun at a spinning temperature of 180 to 350°C, and the taking-up speed is preferably adjusted to about 40 to 1500 m/min. As stretching, if necessary, multi-stage stretching may be performed, and the stretching ratio may be adjusted to about 3 to 9 times. Further, the obtained tow (fiber bundle) is crimped, if necessary, and then cut to a predetermined length to be processed into short fibers. In addition, the tow can be processed into long fibers without cutting.

The method of using the modified single-sided fiber according to the present invention is not particularly limited, but the modified single-sided fiber may be used as a release fiber or a dividable fiber, and preferably, may be suitably used depending on the field in which the fiber is used.

In the present invention, when the deformed sectional fiber according to the present invention is divided and used, the constituents derived by dividing the composite fiber from the deformed sectional fiber is referred to as a composite fiber structure, and when based on the composite fiber structure, it is divided from the structure. Fibers obtained by becoming and inducing are referred to as composite fibers and can be suitably used in many cases. The composite fiber obtained by being derived therefrom is not particularly limited, but may have a structure in which the connector and the composite fiber structure are completely detached or at least a part of the connector remains connected. The composite fibers derived therefrom may have a circular shape or a non-circular shape.

The method of dividing the deformed single-sided fiber is not particularly limited, and the dividing is performed by known methods such as needle punching and high-pressure fluid jet processing after the fibers are processed into webs and nonwovens. It can be carried out, or can be carried out by external stress such as a stretching process in the step of forming the fiber, or by fiber shrinkage in the heat treatment step.

The modified single-sided fiber according to the present invention is not particularly limited. For example, when the fiber is made of a two-component thermoplastic resin, the composite ratio is preferably in the range of 10/90 to 90/10, and more preferably in the range of 30/70 to 70/30 by volume ratio.

The single yarn fineness of the modified single-sided fibers before the fibers according to the invention are divided is preferably in the range of 0.6 to 10 dtex, and more preferably in the range of 1.0 to 6.0 dtex. In addition, when the deformed cross-section fiber is divided by high pressure fluid jet processing, etc., the average single yarn fineness of the single fiber in the ultra-fine conjugate fiber divided from the connector after being divided is preferably 0.5 dtex or less, and more preferably , 0.3 dtex or less.

The modified single-sided fiber according to the present invention can be formed into a fibrous formed body according to the application through high-order work processing, if necessary.

As the fibrous molded body herein, when the body has the form of a fabric, a fibrous molded body may be used, and the body is not particularly limited. Specific examples include woven fabrics, knitted fabrics, and nonwoven fabrics. In addition, the fibers according to the invention may also be mixed with any other fibers, mixed spinning, or processed into fibrous shaped bodies. In addition, the fibrous molded body can be laminated with a uniformed web-shaped material by a carding method, air-laid method or paper-making method, woven fabric, knitted fabric or non-woven fabric. I can.

The fibrous molded body according to the present invention can be used by mixing and spinning of any other fibers to the deformed single-sided fibers by mixing. Specific examples of any of these other fibers are synthetic fibers such as polyamide, polyester, polyolefin and acrylic fibers, natural fibers such as cotton, wool and hemp, recycled Fibers, such as rayon, cupra and acetate, and semisynthetic fibers.

In this step, after the fibers are spun, a surfactant is deposited on the surface of the fibers for the purpose of electrostatic protection of the fibers, thereby providing a fibrous molded body having smoothness to improve processing capability, etc. have. The form and concentration of the surfactant is appropriately adjusted according to the application. As the dipping method, a roller method, a dipping method, and the like can be applied. The surfactant may be deposited in any of the spinning, stretching and crimping steps. In addition, the surfactant may also be deposited in a step other than the spinning step, the stretching step and the crimping step, for example, after forming into a fibrous molded body in connection with short fibers or long fibers.

The length of the modified cross-sectional fiber according to the present invention is not particularly limited. When the web is manufactured using a carding machine, fibers having a length of 20 to 76 mm are generally used, and in the papermaking method or air-laid method, fibers having a length of 2 to 20 mm are preferred. Is used.

As an example of a method of manufacturing a fibrous molded article obtained from a deformed cross-sectional fiber according to the nonwoven fabric of the present invention, a specific example of a method of manufacturing a nonwoven fabric is described.

For example, short fibers produced by a method of producing a deformed cross-section fiber are used to produce a web having a desired basis weight by applying a carding method, an air-laid method or a papermaking method. The fibrous molded body can be obtained by dividing the web produced by the present method into fine fibers by known methods such as needle-punching method and high pressure fluid jet processing. In addition, the fibrous shaped body can also be processed by known working methods such as hot air or heating rolls.

The basis weight of the fibrous molded article according to the present invention is not particularly limited, but is preferably in the range of 10 to 200 g/m ² .

Products obtained using the modified single-sided fibers according to the present invention are excellent in gloss, concealing properties and moisture releasing properties, and thus are preferably used for absorbent products, e.g. diapers, napkins, and incontinence pads. I can. In addition, the nonwoven fabric manufactured using the composite fiber obtained by dividing the deformed cross-section fiber according to the present invention is a variety of textile products, for example, absorbent products including diapers, napkins and incontinence pads, gowns and surgical gowns. Medical and sanitary materials including, wall sheets, shoji paper and indoor interior materials including floor materials, cover cloth, cleaning wiper and kitchen waste cover Life-related materials including garbage cover, disposable toilets and toilet products including toilet seat covers, pet sheets, pet diapers and pets including pet towels Industrial materials including animal products, wiping materials, battery separators, electric windshield wipers, filters, cushioning materials, oil absorbents and absorbents for ink tanks, general medical materials, bedding It can be used in applications for (bed clothing) and nursing care products.

Example

The invention is described in more detail through examples, but the invention is not limited by the examples in any way.

(Thermoplastic resin)

The resin described below was used as a thermoplastic resin constituting the composite fiber.

First thermoplastic resin: propylene homopolymer (abbreviation: PP) having a MFR (at 230°C, load: 21.18 N) of 16 g/10 min and a melting point of 163°C.

Second thermoplastic resin: high-density polyethylene (abbreviation: PE) having a density of 0.96 g/cm ³ , an MFR (at 190°C, load: 21.18N) of 16 g/10 min, and a melting point of 130°C.

Third thermoplastic resin: The same propylene homopolymer as the first thermoplastic resin.

Example 1

(Production of modified single-sided fiber)

Using the first thermoplastic resin (PP), the second thermoplastic resin (PE), and the third thermoplastic resin (PP), the volume ratio of (the first thermoplastic resin and the third thermoplastic resin) to the second thermoplastic resin is 50/50 As shown in Figure 1 (f) through the spinning protrusion for the deformed cross-sectional fiber was spun. Deformed cross-sectional fibers having a microscopic view of 9.5 dtex and a cross-sectional shape shown in FIG. 2 were obtained.

Thereafter, as a surfactant, a fiber treatment agent containing an alkyl phosphate K salt as a main component was contacted with the spun fiber using an oiling roll, and deposited on the fiber.

The obtained unstretched fiber was stretched 6 times using a stretching machine with a stretching temperature set at 90°C, and the fiber was cut into short fibers using a cutter.

As shown in FIG. 3, in the fiber after stretching, a fine composite fiber having a fineness of 0.3 dtex was divided and derived from the fiber. The fibers were divided by stretching, and accordingly, it was confirmed that the modified cross-sectional fibers according to the present invention had a structure in which the fibers could be easily divided.

While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various modifications and modifications can be made in the present invention without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application No. 2014-073057 (filed on March 31, 2014), the contents of which are incorporated herein by reference.

Industrial applicability

The modified single-sided fiber according to the invention can be preferably used in the field of industrial materials, for example battery separators, electric windscreen wipers and filters, and in the field of hygiene materials, for example diapers and napkins.

1A, 1B, 1C, 1D, 1E and 1F: Deformed single-sided fibers
11: first thermoplastic resin
12: second thermoplastic resin
13: third thermoplastic resin
14: composite fiber structure
15: connector
X: length X between the composite fiber structure 14 and the connector 15
Y: maximum width Y of the composite fiber structure 14
Z: the connected portion between the composite fiber structure 14 and the connector 15

Claims (10)

(1) a plurality of pieces of a conjugate fiber structure comprising a first thermoplastic resin and a second thermoplastic resin having a lower melting point or softening point than the first thermoplastic resin; And
(2) As a modified cross-section fiber comprising a connected body comprising a third thermoplastic resin having a higher melting point or softening point than the second thermoplastic resin,
In any fiber cross section, at least two pieces of the composite fiber structure are connected by the connector,
A modified cross-sectional fiber having a structure in which a periphery of the third thermoplastic resin is covered with the second thermoplastic resin. (1) a plurality of pieces of a composite fiber structure comprising a first thermoplastic resin and a second thermoplastic resin having a lower melting point or softening point than the first thermoplastic resin; And
(2) A modified single-sided fiber comprising a connector comprising a third thermoplastic resin having a higher melting point or softening point than the second thermoplastic resin,
In any fiber cross section, at least two pieces of the composite fiber structure are connected by the connector,
In a fiber cross-section, a length of a bond between the composite fiber structure and the connector is less than or equal to the maximum width of the composite fiber structure in a direction perpendicular to the longitudinal direction of the connector. The modified cross-sectional fiber according to claim 1 or 2, wherein the cross-sectional shape of the composite fiber structure is circular or polygonal. The modified single-sided fiber according to claim 1 or 2, comprising 2 to 6 pieces of the composite fiber structure. The modified single-sided fiber according to claim 1 or 2, wherein the first thermoplastic resin and the third thermoplastic resin are the same resin. The modified single-sided fiber according to claim 1 or 2, wherein the second thermoplastic resin occupies the surface of the composite fiber structure except for a portion connected to the connector. The modified single-sided fiber according to claim 1 or 2, wherein the third thermoplastic resin occupies 20% or more of the cross-section of the connector. The modified single-sided fiber according to claim 1 or 2, wherein the second thermoplastic resin included in the connecting body and the second thermoplastic resin included in the composite fiber structure are melted and integrated. The one piece of the composite fiber structure according to claim 1 or 2, wherein three pieces of the composite fiber structure are arranged at equal intervals around the one piece of the composite fiber structure positioned at the center. Including a structure that is each connected by the connector, the heteromorphic cross-section fiber.
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