JP7140774B2 - Fiber structure and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fibrous structure that can be suitably used as a bandage or the like, and a method for producing the same.

BACKGROUND ART Conventionally, in fields such as medicine and sports, tapes such as various bandages and supporters have been used for the purpose of appropriately compressing, fixing, and protecting application sites such as limbs and affected areas. These tapes are required to have stretchability, followability, sweat absorption, air permeability, and the like, and also to have self-adhesive or adhesive fixability.

In general, a soft component such as rubber or acrylic latex is applied to the surface of the bandage for the purpose of achieving stretchability and fixing properties (Patent Documents 1 to 5). However, these soft components are not preferable from the viewpoint of safety because they may irritate the skin, cause stuffiness due to blockage of air permeability, and may even cause allergies.

For the purpose of reducing skin irritation, medical materials using low-protein natural rubber latex as an adhesive (Patent Document 6) and self-adhesive bandages using a specific acrylic polymer as an adhesive (Patent Document 7) is proposed. However, even in these medical materials and self-adhesive bandages, there is no change in the use of adhesives, and it is not a fundamental solution.

As a nonwoven fabric that can be self-adhered without applying an adhesive, a nonwoven fabric that has elasticity and can be easily cut by hand using a conjugate fiber that has latent heat crimpability (Patent Document 8), or a nonwoven fabric that can be easily cut by hand (Patent Document 8) A high stress type stretchable nonwoven fabric has been proposed (US Pat.

Japanese Patent Publication No. 48-000309 JP-A-63-068163 JP-A-63-260553 JP-A-01-19035 JP-A-11-089874 Japanese translation of PCT publication No. 2003-514105 JP 2005-095381 A WO2008/015972 WO2016/031818

However, it has been found that the nonwoven fabric described in Patent Document 8 is easily torn when it is tightly wound. In addition, since the nonwoven fabric described in Patent Document 9 has high stress, it has a characteristic that it is difficult to tear even when it is tightly wound. It turns out there is room.

Therefore, the present invention has a very low stress at low elongation and excellent initial conformability, but it has a very high stress at high elongation, can be tightly wound, and is easy to stretch but hard to break. The purpose is to provide a structure.

The inventors of the present invention have found that the nonwoven fabric described in Patent Document 8 has low strength and is easy to stretch because crimps are entangled with each other, but it is likely to break. In addition, in the nonwoven fabric obtained by entangling by the spunlace method or needle punching method described in Patent Document 9 and then treating with high-speed steam, the sheet itself is entangled, and the developed crimp cannot be utilized, resulting in shrinkage. was found to be difficult to obtain.

As a result of intensive studies to achieve the above object, the present inventors have found that the entangled portion (A) composed of the coiled crimped fibers (a) and the non-coiled crimped fibers (b) The fiber structure has two or more entangled portions (B), and the distance between at least one entangled portion (B) in the machine direction of the fiber structure is the apparent average fiber length of the coiled crimped fiber (a). It has been found that the above object can be achieved with a fibrous structure having a weight of less than .

That is, the present invention includes the following.
[1] A fibrous structure comprising coiled crimped fibers (a) and non-coiled crimped fibers (b), wherein the fibrous structure is entangled with the coiled crimped fibers (a) A fiber structure having a portion (A) and two or more entangled portions (B) composed of uncoiled crimped fibers (b), and between at least one entangled portion (B) in the machine direction of the fiber structure is less than the apparent average fiber length of the coiled crimped fibers (a).
[2] The fiber structure according to [1], wherein the ratio of the area of the entangled portion (A) to the surface area of the fiber structure is 20 to 85% on the surface of the fiber structure.
[3] The ratio of the thickness (T _A ) of the intertwined portion (A) to the thickness (T _B ) of the intertwined portion (B) is T _A /T _B =1.1 to 10, [ 1] or the fiber structure according to [2].
[4] The fiber structure according to any one of [1] to [3], wherein the stress at 50% elongation in the machine direction of the fiber structure is 15 N/5 cm or less and the stress at 80% elongation is 20 N/5 cm or more. fibrous structure.
[5] The ratio of the stress at 50% elongation to the stress at 80% elongation in the machine direction of the fiber structure, wherein the stress at 80% elongation/stress at 50% elongation is 2.7 or more, [1] to [4 ] The fiber structure according to any one of .
[6] The fiber according to any one of [1] to [5], wherein the coiled crimped fiber (a) is composed of composite fibers in which a plurality of resins having different heat shrinkage rates form a phase structure. Structure.
[7] The fiber structure according to any one of [1] to [6], which has a basis weight of 50 to 200 g/m ² .
[8] A bandage comprising the fiber structure according to any one of [1] to [7].
[9] A method for manufacturing a fiber structure according to any one of [1] to [8],
1) a step of web-forming the fibers;
2) entangling portions of the web by spraying or jetting water to form entangled portions (B); and 3) heating the web with high-temperature steam to form entangled portions (A). ,Production method.

INDUSTRIAL APPLICABILITY The fiber structure of the present invention can be suitably used for bandages and the like because it has excellent initial conformability and can be tightly wound.

FIG. 1 is a schematic diagram showing the arrangement pattern of the entangled portions (B) in the machine direction of the fiber structure obtained in Example 1. FIG. FIG. 2 is a schematic diagram showing a method of preparing a sample for measuring curved surface sliding stress. It is a cross-sectional schematic diagram which shows the sample for measuring curved-surface sliding stress. It is a schematic diagram which shows the measuring method of curved-surface sliding stress.

[Fibrous structure]
The fiber structure of the present invention (hereinafter also simply referred to as "fiber structure") is composed of the entangled portion (A) composed of the coiled crimped fibers (a) and the non-coiled crimped fibers (b). and an intertwined portion (B). The fiber structure of the present invention has a structure in which the coiled crimped fibers (a) are entangled with each other at the crimped coil portions and restrained or hooked at the entangled portion (A). On the other hand, in the entangled portion (B), the entangled portion is formed by compacting the fibers without crimping the non-coiled crimped fibers (b). The coiled crimped fibers (a) and the non-coiled crimped fibers (b) are preferably oriented in the machine direction of the fiber structure, and the coiled crimped fibers (a) are oriented along this orientation axis. It is preferably crimped into a coil shape.

The flow direction of the fiber structure is the flow direction (MD direction) of the fiber structure in the manufacturing process. is preferably In this case, the fiber structure, which is a bandage, can be wrapped around the application site while being stretched along its length direction. When the fiber structure has a length direction and a width direction, the CD direction, which is perpendicular to the MD direction, is preferably the width direction.

In the fiber structure of the present invention, since the fibers are relatively weakly entangled in the entangled portion (A), the stress is very low when stretched at a low level and the initial conformability is excellent. In addition, since the fibers are strongly entangled in the entangled portion (B), the stress becomes very high when the fiber is stretched at a high degree, and it becomes possible to wind the fiber.

In the fiber structure of the present invention, the distance between at least one entangled portion (B) in the machine direction of the fiber structure (hereinafter also simply referred to as "the distance between the entangled portions (B)") is a coiled winding. It is less than the apparent average fiber length of the crimped fibers (a). The distance between the entangled portions (B) in the flow direction of the fiber structure means the distance between any one entangled portion (B) of the fiber structure and the distance closest to this entangled portion (B) in the flow direction. It means the shortest distance in the flow direction between other existing entangled portions (B). When the distance between the entangled portions (B) is equal to or greater than the apparent average fiber length of the coiled crimped fibers (a), the distance between the entangled portions (B) is the crimped coil portion of the coiled crimped fibers (a). At high elongation, the entangled coil part is stretched and finally unraveled, so that it tends to be easily cut at the part. On the other hand, when the distance between the entangled portions (B) is less than the apparent average fiber length of the coiled crimped fibers (a), at least one end of the coiled crimped fibers (a) is entangled in the entangled portions (B). As a result, the coiled crimped fibers (a) do not unravel even when stretched at high speeds, and tend to exhibit high stress at high stretches. From the above viewpoint, it is preferable that both ends of at least part of the coiled crimped fibers (a) are entangled at the entangled portion (B).

The two entangled portions (B) forming the distance between the entangled portions (B) are arranged so that at least a portion thereof can be entangled with the coiled crimped fibers (a) oriented in the machine direction. preferably. When the entangled portion (B) is entangled with the coiled crimped fiber (a), high stress tends to be obtained during high elongation. As the number of coiled crimped fibers (a) that are entangled with the entangled portion (B) increases, there is a tendency that the entangled portion (B) and the coiled crimped fiber (a) are more likely to be strongly entangled. . When the fiber structure is in the form of a sheet, the entangled portions (B) may be formed regularly in the plane of the sheet. It can be arranged in a border-like pattern that is alternately arranged, or a planar lattice-like pattern in which intertwined portions (B) having a specific shape are regularly arranged, such as a square lattice pattern, an orthorhombic lattice pattern, a rectangular lattice pattern, or the like. preferable. FIG. 1 shows an entangled portion (B) 2, an entangled portion (A) 3, and a distance between the entangled portions (B) of a fiber structure 1 having an orthorhombic lattice pattern obtained in Example 1 described later. 4 is shown.

When the entangled portions (B) are arranged in a border-like pattern, the width (length in the machine direction) of the entangled portions (B) may be, for example, 0.5 to 30 mm, preferably 1 to 20 mm, more It is preferably 2 to 10 mm, more preferably 3 to 8 mm.

When the intertwined portions (B) are arranged in a planar lattice pattern, the interval in the direction perpendicular to the flow direction (interval in the direction perpendicular to the "distance between the intertwined portions (B)") is For example, it may be 0.5 to 30 mm, preferably 1 to 20 mm, more preferably 2 to 10 mm, even more preferably 3 to 8 mm.

When the intertwined portions (B) are arranged in a planar lattice pattern, the shape of the intertwined portions (B) is not particularly limited, but may be oval, elliptical, circular, square, rectangular, or the like. , preferably oblong. In the case of an oval shape, the length in the major axis direction may be, for example, 1 to 80 mm, preferably 5 to 60 mm, more preferably 10 to 40 mm, and the length in the minor axis direction is, for example, 1 to 80 mm. It is preferably 3 to 50 mm, more preferably 5 to 30 mm.

The fiber structure tends to exhibit high stress during high elongation as the proportion of the entangled portions (B) between the entangled portions (B) is less than the apparent average fiber length of the coiled crimped fibers (a). Therefore, in the fiber structure, for example, 10% or more of the entangled portions (B) in the machine direction of the fiber structure have a distance between them less than the apparent average fiber length of the coiled crimped fibers (a). is preferably 30% or more, more preferably 60% or more, still more preferably 90% or more, and particularly preferably 95% or more of the distance between the entangled portions (B) existing in the flow direction of the fiber structure. , the distance between them is less than the apparent average fiber length of the coiled crimped fibers (a).

The apparent average fiber length of the coiled crimped fibers (a) (hereinafter also simply referred to as "apparent average fiber length") is the fiber length obtained by stretching the coiled crimped fibers into a straight line (actual fiber length). Instead, it is the average value of the fiber length (apparent fiber length) in a coiled crimped state. Therefore, the apparent average fiber length is measured shorter than the actual fiber length. The apparent average fiber length is measured by an electron microscope on the surface of the fiber structure, and any of the coiled crimped fibers (a) existing per 1 cm ² of the surface of any entangled portion (A) of the fiber structure 100 selected apparent fiber lengths were measured, and the average value was obtained.

The apparent average fiber length may be, for example, 10 mm or longer, preferably greater than 10 mm, more preferably 11 mm or longer, still more preferably 12 mm or longer, and particularly preferably 13 mm or longer. On the other hand, the apparent average fiber length may be, for example, 70 mm or less, preferably 55 mm or less, more preferably 40 mm or less, still more preferably 30 mm or less, and particularly preferably 21 mm or less.

The distance between the entangled portions (B) may be, for example, 2.5 mm or more, preferably 3 mm or more, more preferably 3.5 mm or more. At least one of the distances between the entangled portions (B) may be, for example, 20 mm or less, preferably less than 20 mm, more preferably 15 mm or less, still more preferably 10 mm or less. When at least one of the distances between the entangled portions (B) is between the upper limit value and the lower limit value, the entangled portions (B) are entangled by the coiled crimped fibers (a), It becomes highly stressed at high elongation, and tends to be difficult to tear even when tightly wound.

In the present invention, the entangled portion (B) may contain a small amount of the coiled crimped fiber (a), for example, up to 3% by mass with respect to the total mass of the entangled portion (B). The entangled portion (A) may contain a small amount of non-coiled crimped fibers (b), for example up to 3% by weight relative to the total weight of the entangled portion (A). Also, one fiber may have a coiled crimped portion and a non-coiled crimped portion.

In the fiber structure, on the surface of the fiber structure, the ratio of the area of the entangled portion (A) to the surface area of the fiber structure may be, for example, 20 to 85%, preferably 30 to 83%, More preferably 40 to 81%. The area of the entangled portion (A) is a value determined by the measuring method described in the examples below. When the ratio of the area of the entangled portion (A) is within the above range, the stress during low elongation tends to be low and excellent conformability tends to be obtained.

In the fiber structure, the ratio T _A /T _B between the thickness (T _{A ) of the entangled portion (A} ) and the thickness (T _B ) of the entangled portion (B) may be, for example, 1.1 to 10. , preferably 2-7, more preferably 3-5. When the ratio T _A /T _B of the thickness (T _A ) of the entangled portion (A) to the thickness (T _B ) of the entangled portion (B) is within the above range, it is advantageous in terms of good balance between softness and strength. is.

The thickness (T _A ) of the entangled portion (A) may be, for example, 1 to 10 mm, preferably 1.5 to 7 mm, more preferably 2 to 5 mm.

The thickness (T _B ) of the entangled portion (B) may be, for example, 0.2 to 1 mm, preferably 0.3 to 0.9 mm, more preferably 0.4 to 0.8 mm.

The thickness (T _A ) of the entangled portion (A) and the thickness (T _B ) of the entangled portion (B) were measured in accordance with JIS L1913 "Test method for general staple fiber nonwoven fabric".

The fabric weight of the fiber structure is preferably 50-200 g/m ² , more preferably 70-180 g/m ² .

When the basis weight and thickness are within the above ranges, the fiber structure has a good balance of stretchability, flexibility, texture and cushioning properties. The densities (bulk densities) of the entangled portions (A) and (B) of the fiber structure can be values according to the basis weight and thickness. The density (bulk density) of the entangled portion (A) of the fiber structure may be, for example, 0.03-0.15 g/cm ³ , preferably 0.04-0.1 g/cm ³ . The density (bulk density) of the entangled portion (B) of the fiber structure can be a value according to the basis weight and thickness, for example 0.15 to 1.5 g/cm ³ , preferably 0.2. ˜1 g/cm ³ .

The fibrous structure may have a stress at 50% elongation in the machine direction of, for example, 15 N/5 cm or less, preferably 13 N/5 cm or less, more preferably 12 N/5 cm or less. When the stress at 50% elongation in the machine direction of the fiber structure is equal to or less than the above upper limit, the stress is low at low elongation, and the initial conformability tends to be excellent. Although the lower limit of the stress at 50% elongation in the machine direction of the fiber structure is not particularly limited, it may be, for example, 1 N/5 cm or more.

The fibrous structure may have a stress at 80% elongation in the machine direction of, for example, 20 N/5 cm or more, preferably 25 N/5 cm or more, and more preferably 30 N/5 cm or more. When the stress at 80% elongation in the machine direction of the fiber structure is the above value or more, the stress becomes high at high elongation, and there is a tendency that the fiber structure does not tear easily even when it is tightly wound. Although the upper limit of the stress at 80% elongation in the machine direction of the fiber structure is not particularly limited, it is usually, for example, 50 N/5 cm or less.

In the fiber structure, the ratio of the stress at 50% elongation to the stress at 80% elongation in the flow direction of the fiber structure may be, for example, 2.7 or more, It is preferably 3.0 or more, more preferably 3.2 or more. When the ratio of the stress at 50% elongation and the stress at 80% elongation in the flow direction of the fiber structure is equal to or higher than the above lower limit, the stress is low at low elongation, and the initial conformability is excellent, but at high elongation. It has a high stress and tends to be difficult to tear even when tightly wound. The ratio of the stress at 50% elongation and the stress at 80% elongation in the machine direction of the fiber structure is not particularly limited, but may be, for example, 10 or less, preferably 8. 5 or less, more preferably 5 or less.

The stress at 50% elongation and the stress at 80% elongation in the machine direction of the fiber structure respectively mean the stress at elongation immediately after stretching the fiber structure in the machine direction at an elongation rate of 50% and 80%, JIS L 1913 It can be measured by a tensile test conforming to the "general nonwoven fabric test method". The stress at 50% elongation and the stress at 80% elongation in the machine direction of the fiber structure of the present invention are values obtained using AG-IS manufactured by Shimadzu Corporation as a constant speed elongation type tensile tester.

The fiber structure may have a recovery rate after 50% elongation in at least one direction (hereinafter also referred to as a recovery rate after 50% elongation) of, for example, 70% or more, preferably 80% or more, more preferably 90%. % or more. Although the upper limit of the recovery rate after 50% elongation is not particularly limited, it is usually 100% or less. When the 50% elongation recovery rate is within the above range, the followability to elongation is improved. It is advantageous for improving self-adhesiveness due to friction between bodies. If the elongation recovery rate is excessively small, the fiber structure will not be able to follow the movement of the part where it is used if it has a complicated shape or if it moves during use, and the part that is deformed by the movement of the body. does not return to its original state, weakening the fixation of the wound fiber structure.

Said at least one direction is preferably the machine direction of said fibrous structure. If the fiber sheet has a length direction and a width direction, such as a bandage, the length direction of the fiber sheet is preferred.

The recovery rate after 50% elongation is the residual strain (%) after the test when the load is removed immediately after the elongation reaches 50% in a tensile test conforming to JIS L 1913 "General nonwoven fabric test method". is X, the following formula:
Recovery rate after 50% elongation (%) = 100-X
defined by

The recovery rate after 50% elongation in a direction other than the at least one direction of the fiber structure, such as the CD direction, or in the width direction when the fiber structure has a length direction and a width direction like a bandage is, for example, 70% or more. (100% or less), preferably 80% or more.

The fibrous structure preferably exhibits self-adhesion. As used herein, the term "self-adhesiveness" refers to the property that fibers on the surface of a fiber structure can be interlocked or fixed by overlapping (contacting) the fibers with each other. Having self-adhesion is advantageous when the fibrous structure is a bandage or the like. For example, when the fiber structure is a bandage, the bandage is wrapped around the application site, and then the ends of the bandage are overlapped on the underlying surface of the bandage, thereby stretching and pressing the wound fiber sheets together. The fiber structures are bonded and fixed to each other, and exhibit self-adhesiveness.

The self-adhesiveness of the fiber structure allows the formation of a layer of self-adhesive agents such as elastomers and adhesives on the surface of the fiber structure, and a separate stopper is prepared to fix the tip after winding. You don't have to do anything. The fiber structure is preferably composed only of a non-elastomeric material, and more specifically preferably composed only of fibers. For example, Japanese Patent Application Laid-Open No. 2005-095381 (Patent Document 7, Claim 1, paragraphs [0004] to [0006]) discloses that an acrylic polymer or latex is attached as a self-adhesive to at least one side of the bandage base material. is described. However, forming such a layer of elastomer on the surface of the fiber sheet may cause problems such as obstruction of blood circulation and pain when the fiber sheet is wrapped around the application site for a long time. In addition, a layer made of elastomer may induce skin irritation or allergy when wrapped around the application site.

The self-adhesiveness of the fiber structure can be evaluated by curved surface sliding stress. The fiber structure may have a curved surface sliding stress of, for example, 1 N/50 mm or more, preferably 3 N/50 mm or more, and the curved surface sliding stress is preferably greater than the breaking strength. When desired, the curved surface sliding stress is preferably 30 N/50 mm or less, more preferably 25 N/50 mm or less, because it is relatively easy to unwind the wound fiber structure. The curved surface sliding stress can be measured using a tensile tester according to the method described in the Examples section (FIGS. 2 to 4).

The fibrous structure preferably has hand tearability. As used herein, the term "hand tearability" refers to the property of being able to break (cut) by pulling by hand. The hand tearability of the fiber structure can be evaluated by breaking strength. When the fiber structure is sheet-like, the breaking strength in at least one direction in the plane is preferably 5 to 100 N/50 mm, more preferably 8 to 60 N/50 mm, more preferably 10 to 10 mm, from the viewpoint of hand tearability. It is 40N/50mm. When the breaking strength is within the above range, it is possible to impart good hand tearability so that it can be broken (cut) relatively easily by hand. If the breaking strength is too high, the hand-cutting property tends to be low, and it tends to be difficult to cut the fiber structure with one hand, for example. On the other hand, if the breaking strength is too low, the strength of the fiber structure will be insufficient and it will easily break, and the durability and handleability will tend to deteriorate. Breaking strength can be measured by a tensile test conforming to JIS L 1913 "General nonwoven fabric test method".

At least one direction in the plane of the sheet is the tensile direction when the fiber structure is cut by hand, preferably the flow direction of the fiber structure. If the fibrous structure has a length direction and a width direction, such as a bandage, the length direction of the fibrous structure is preferred. That is, when the fiber structure is used as a bandage, the bandage is usually stretched along its length direction and wound around the application site, and then broken in the length direction. is preferably in the longitudinal direction.

The breaking strength in a direction other than at least one direction in the plane of the sheet, such as the CD direction, or in the width direction when the fiber sheet has a length direction and a width direction like a bandage is, for example, 0.1 to 300 N/50 mm. It may be, preferably 0.5 to 100 N/50 mm, more preferably 1 to 20 N/50 mm.

From the standpoint of hand tearability, the fiber structure is preferably composed only of a non-elastomeric material, and more specifically preferably composed only of fibers. If a layer made of elastomer or the like is formed on the surface of the fiber structure, hand tearability may be lowered.

The fiber structure may have a breaking elongation of, for example, 50% or more, preferably 60% or more, and more preferably 80% or more in at least one direction in the sheet plane. A breaking elongation within the above range is advantageous for increasing the stretchability of the fiber structure. In addition, when the fiber structure is used as a bandage, it is possible to improve the followability when applying this to a portion such as a joint where there is a large amount of movement. The elongation at break in at least one direction in the plane of the sheet is usually 300% or less, preferably 250% or less. The elongation at break can also be measured by a tensile test conforming to JIS L 1913 "General test method for nonwoven fabrics".

At least one direction in the sheet plane is preferably the first direction. This first direction can be the MD direction, and is preferably the length direction of the fibrous structure if the fibrous structure has a length direction and a width direction, such as a bandage.

The breaking elongation in a direction other than at least one direction in the plane of the sheet, such as the CD direction, or in the width direction when the fiber structure has a length direction and a width direction like a bandage is, for example, 10 to 500%. preferably 100-350%.

The coiled crimped fiber (a) can be composed of a conjugate fiber (hereinafter also simply referred to as "conjugate fiber") having latent heat crimpability.

Composite fibers are composite fibers in which a plurality of resins with different coefficients of thermal shrinkage or thermal expansion form a phase structure. It is a fiber having a (so-called bimetallic) structure. Resins typically have different softening or melting points. The plurality of resins may be, for example, polyolefin resins (e.g., low-density, medium-density or high-density polyethylene, _polyC2-4 olefin resins such as polypropylene), acrylic resins (e.g., acrylonitrile-vinyl chloride copolymer, etc.). Acrylonitrile-based resins having acrylonitrile units, etc.), polyvinyl acetal-based resins (eg, polyvinyl acetal resins, etc.), polyvinyl chloride-based resins (eg, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, vinyl chloride-acrylonitrile copolymers, etc.) ), polyvinylidene chloride resins (eg, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-vinyl acetate copolymer, etc.), styrene resins (eg, heat-resistant polystyrene, etc.), polyester resins (eg, polyethylene terephthalate resin, polytri Poly C _2-4 alkylene arylate resins such as methylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, etc.), polyamide resins (eg, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, etc. Aliphatic polyamide resins, semi-aromatic polyamide resins, aromatic polyamide resins such as polyphenylene isophthalamide, polyhexamethylene terephthalamide, poly p-phenylene terephthalamide, etc.), polycarbonate resins (e.g., bisphenol A type polycarbonate, etc. ), polyparaphenylenebenzobisoxazole resin, polyphenylene sulfide resin, polyurethane resin, cellulose resin (for example, cellulose ester), and other thermoplastic resins. Furthermore, each of these thermoplastic resins may contain other copolymerizable units.

Among them, from the viewpoint that the fibers do not melt or soften even when heated with high-temperature steam, non-wet heat adhesive resins (or heat-resistant hydrophobic resins or non-aqueous resins) having a softening point or melting point of 100 ° C. or higher, For example, polypropylene-based resins, polyester-based resins and polyamide-based resins are preferable, and aromatic polyester-based resins and polyamide-based resins are more preferable in terms of excellent balance of heat resistance and fiber forming properties. In the present invention, the resin exposed on the surface of the composite fiber is preferably a non-wet heat adhesive fiber so that the fibers constituting the fiber structure are not fused even when treated with high-temperature steam.

A plurality of resins constituting the conjugate fiber may have different thermal shrinkage rates, and may be a combination of resins of the same type or a combination of different types of resins.

In the present invention, from the viewpoint of adhesiveness, it is preferable to use a combination of resins of the same type. In the case of a combination of resins of the same type, a combination of component (A) forming a homopolymer and component (B) forming a modified polymer (copolymer) is usually used. That is, for example, the homopolymer is modified by copolymerizing a copolymerizable monomer that lowers the crystallinity, melting point, softening point, etc., so that the crystallinity is lower than that of the homopolymer. Alternatively, it may be made amorphous and have a lower melting point or softening point than the homopolymer. Thus, by changing the crystallinity, melting point, or softening point, a difference in thermal shrinkage may be provided. The difference in melting point or softening point may be, for example, 5 to 150.degree. C., preferably 50 to 130.degree. C., more preferably 70 to 120.degree. The proportion of the copolymerizable monomer used for modification may be, for example, 1 to 50 mol%, preferably 2 to 40 mol%, more preferably 3 to 30 mol% ( In particular, it is about 5 to 20 mol %). The composite ratio (mass ratio) of the component forming the homopolymer and the component forming the modified polymer can be selected according to the structure of the fiber. , for example, 90/10 to 10/90, preferably 70/30 to 30/70, more preferably about 60/40 to 40/60.

From the viewpoint of facilitating the production of latent crimpable conjugate fibers, the conjugate fiber is a combination of aromatic polyester-based resins, particularly a combination of polyalkylene arylate-based resin (a) and modified polyalkylene arylate-based resin (b). may be The polyalkylene arylate resin (a) contains aromatic dicarboxylic acids (symmetrical aromatic dicarboxylic acids such as terephthalic acid and naphthalene-2,6-dicarboxylic acid) and alkanediol components (C _{2- 6} -alkanediol, etc.). Specifically, poly C _2-4 alkylene terephthalate resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are used. PET used for fibers is used.

On the other hand, in the modified polyalkylene arylate-based resin (b), the melting point or softening point of the polyalkylene arylate-based resin (a), a copolymerization component that lowers the degree of crystallinity, for example, an asymmetric aromatic dicarboxylic acid, an alicyclic A dicarboxylic acid component such as a dicarboxylic acid or an aliphatic dicarboxylic acid, an alkanediol component having a longer chain length than the alkanediol of the polyalkylene arylate resin (a), and/or an ether bond-containing diol component can be used.

These copolymer components can be used alone or in combination of two or more. Among these components, dicarboxylic acid components include asymmetric aromatic dicarboxylic acids (isophthalic acid, phthalic acid, 5-sodium sulfoisophthalic acid, etc.), aliphatic dicarboxylic acids (C _6-12 aliphatic dicarboxylic acids such as adipic acid, ) and the like are widely used, and as diol components, alkanediols (1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc., C _3-6 alkanediols, etc.), polyoxyalkylene Glycols (diethylene glycol, triethylene glycol, polyethylene glycol, polyoxy C _2-4 alkylene glycol such as polytetramethylene glycol, etc.) and the like are widely used. Among these, asymmetric aromatic dicarboxylic acids such as isophthalic acid and polyoxy C _2-4 alkylene glycols such as diethylene glycol are preferred. Furthermore, the modified polyalkylene arylate resin (b) may be an elastomer having C _2-4 alkylene arylates (ethylene terephthalate, butylene terephthalate, etc.) as hard segments and (poly)oxyalkylene glycol as soft segments. .

In the modified polyalkylene arylate resin (b), the dicarboxylic acid component for lowering the melting point or softening point (e.g., isophthalic acid) has a ratio of, for example, 1 to the total amount of the dicarboxylic acid component. It may be up to 50 mol %, preferably 5 to 50 mol %, more preferably about 15 to 40 mol %. As a diol component, the proportion of a diol component (e.g., diethylene glycol) for lowering the melting point or softening point may be, for example, 30 mol% or less, preferably 10 mol% or less ( For example, about 0.1 to 10 mol %). If the proportion of the copolymer component is too low, sufficient coil-like crimping will not develop, and the fiber structure will have reduced morphological stability and stretchability after crimping. On the other hand, if the proportion of the copolymer component is too high, the ability to develop coiled crimps increases, but stable spinning becomes difficult.

The modified polyalkylene arylate-based resin (b) may optionally contain polycarboxylic acid components such as trimellitic acid and pyromellitic acid, polyol components such as glycerin, trimethylolpropane, trimethylolethane, and pentaerythritol. It may be included as a monomer component.

The cross-sectional shape of the composite fiber (the cross-sectional shape perpendicular to the length direction of the fiber) is a general solid cross-sectional shape such as a round cross-section or an irregular cross-section [flat, elliptical, polygonal, 3-14 lobe-shaped, T-shaped, H-shaped, V-shaped, dogbone (I-shaped), etc.], and may have a hollow cross-section, etc., but usually has a round cross-section.

As the cross-sectional structure of the composite fiber, there are phase structures formed in multiple resins, such as core-sheath type, sea-island type, blend type, side-by-side type (side-by-side type or multi-layer lamination type), radial type (radial lamination type). ), hollow radiation type, block type, random composite type, and the like. Of these cross-sectional structures, from the viewpoint of facilitating spontaneous crimping by heating, a structure in which the phase portions are adjacent (so-called bimetallic structure) or a structure in which the phase structure is asymmetrical, such as an eccentric sheath-core type, A side-by-side structure is preferred.

In addition, when the composite fiber has a core-sheath structure such as an eccentric core-sheath type, if it can be crimped with a difference in heat shrinkage from the non-wet heat adhesive resin of the sheath located on the surface, the core is Composed of wet heat adhesive resin (e.g. vinyl alcohol polymer such as ethylene-vinyl alcohol copolymer or polyvinyl alcohol) or thermoplastic resin with low melting point or softening point (e.g. polystyrene or low density polyethylene) may have been

The average fineness of the conjugate fiber may be, for example, 1-5 dtex, preferably 1.3-4 dtex, more preferably 1.5-3 dtex. If the fineness is too fine, it will be difficult to manufacture the fiber itself, and it will also be difficult to secure the fiber strength. In addition, in the step of developing crimps, it becomes difficult to develop neat coiled crimps. On the other hand, if the fineness is too thick, the fibers become rigid and it becomes difficult to develop sufficient crimps.

The average fiber length (actual fiber length) of the conjugate fiber may be, for example, 20-70 mm, preferably 25-65 mm, more preferably 40-60 mm. If the fiber length is too short, it becomes difficult to form a fibrous web, and in addition, the entanglement of the fibers becomes insufficient in the process of developing crimps, making it difficult to ensure strength and stretchability. On the other hand, if the fiber length is too long, it becomes difficult to form a fibrous web with a uniform basis weight. It becomes difficult to develop stretchability. Furthermore, in the present invention, when the fiber length is within the above range, part of the fibers crimped on the surface of the fiber structure are exposed appropriately on the surface of the fiber structure, so that the self-adhesion of the fiber structure can be improved.

When the conjugate fiber is heat-treated, the crimp is expressed (actuated), and the fiber becomes a fiber having a substantially coil-like (helical or helical spring-like) three-dimensional crimp.

The number of crimps before heating (the number of mechanical crimps) may be, for example, 0 to 30/25 mm, preferably 1 to 25/25 mm, and more preferably 5 to 20/25 mm. The number of crimps after heating may be, for example, 20 to 120/25 mm, preferably 25 to 120/25 mm.

The coiled crimped fibers (a) have substantially coiled crimps as described above. The average radius of curvature of the circle formed by the coil of crimped fibers can be selected, for example, from a range of about 10 to 250 μm, for example, 20 to 200 μm (eg, 50 to 200 μm), preferably 50 to 160 μm (eg, 60 to 150 μm), more preferably about 70 to 130 μm. Here, the average radius of curvature is an index representing the average size of a circle formed by a coil of crimped fibers. When this value is large, the formed coil has a loose shape, in other words It means having a shape with a small number of crimps. In addition, when the number of crimps is small, entanglement between fibers is also reduced, which tends to be disadvantageous for exhibiting sufficient stretchability. Conversely, when coiled crimps with an average radius of curvature that is too small are developed, the fibers are not sufficiently entangled with each other, making it difficult to secure the web strength and causing such crimps. The production of latently crimped fibers also tends to be very difficult.

In the coiled crimped fiber (a), the average coil pitch is preferably 0.03 to 0.5 mm, more preferably 0.03 to 0.3 mm, still more preferably 0.05 to 0.2 mm.

The non-coiled crimped fibers (b) may be composed of the conjugate fibers used for the coiled crimped fibers (a) described above, or may be composed of fibers other than the conjugated fibers (non-conjugated fibers). . When the same composite fiber is used for the coiled crimped fiber (a) and the non-coiled crimped fiber (b), it tends to be advantageous from the standpoint of simplicity of the manufacturing process. In addition, regardless of the types of fibers that make up the coiled crimped fibers (a) and the non-coiled crimped fibers (b), the fiber structure has other fibers (non-composite fibers) in the entangled portion (A). and/or in the entangled portion (B) in an amount within the range that the object of the present invention is achieved.

Examples of non-composite fibers include fibers composed of the above-mentioned non-wet heat adhesive resin or wet heat adhesive resin, cellulosic fibers [e.g., natural fibers (cotton, wool, silk, linen, etc.), semi-synthetic fibers (acetate fiber such as triacetate fiber, etc.), regenerated fiber (rayon, polynosic, cupra, lyocell (eg, registered trade name: “Tencel”, etc.), etc.), etc.]. The average fineness and average fiber length of the non-composite fibers are similar to those of the composite fibers. These non-composite fibers can be used alone or in combination of two or more. Among these non-composite fibers, preferred are regenerated fibers such as rayon, semi-synthetic fibers such as acetate, polyolefin fibers such as polypropylene fibers and polyethylene fibers, polyester fibers, and polyamide fibers. In particular, in terms of blendability, the same type of fiber as the conjugated fiber may be used. For example, when the conjugated fiber is a polyester fiber, the non-conjugated fiber may also be a polyester fiber.

When the fiber structure contains conjugated fibers and non-conjugated fibers in the entangled portion (A) and/or the entangled portion (B), the ratio (mass ratio) of the conjugated fibers to the non-conjugated fibers is, for example, the conjugated fibers / non-composite fiber = 80/20 to 100/0 (eg, 80/20 to 99/1), preferably 90/10 to 100/0, more preferably about 95/5 to 100/0 be. By blending non-composite fibers, the strength of the fiber structure can be adjusted. However, if the ratio of conjugated fibers (latently crimped fibers) is too small, when the crimped fibers contract after crimping, the non-conjugated fibers resist the contraction, especially when the crimped fibers contract after elongation. It tends to be difficult to ensure stress.

The fiber structure (fiber web) further contains conventional additives such as stabilizers (heat stabilizers such as copper compounds, ultraviolet absorbers, light stabilizers, antioxidants, etc.), antibacterial agents, deodorants, Perfumes, colorants (dyes and pigments, etc.), fillers, antistatic agents, flame retardants, plasticizers, lubricants, crystallization rate retardants, and the like may be contained. These additives can be used alone or in combination of two or more. These additives may be carried on the fiber surface or contained in the fiber.
[Manufacturing method of fiber structure]
The method for producing a fiber structure of the present invention comprises: 1) a step of forming fibers into a web (hereinafter also referred to as a web forming step); 2) a part of the web is entangled by spraying or jetting water to ) (hereinafter also referred to as entanglement step 1), and 3) a step of heating the web with high-temperature steam to form an entangled portion (A) (hereinafter also referred to as entanglement step 2).

In the web-making process, as a method of forming a web, a conventional method such as a direct method such as a spunbond method or a melt-blown method, a card method using melt-blown fibers or staple fibers, or a dry method such as an air-lay method is used. can. Among these methods, a carding method using melt-blown fibers or staple fibers, particularly a carding method using staple fibers, is widely used. Webs obtained using staple fibers include, for example, random webs, semi-random webs, parallel webs, and crosslap webs.

Next, in the entangling step 1, part of the obtained fiber web is entangled by spraying or jetting water to form an entangled portion (B). The water to be sprayed or jetted may be sprayed from one surface of the fiber web or from both surfaces, but from the viewpoint of efficient strong entangling, it is preferable to spray from both surfaces. The portion to which water is sprayed becomes the entangled portion (B), and the portion to which water is not sprayed becomes the entangled portion (A) in the subsequent entangling step 2.

As a method for forming the entangled portion (B), for example, a plate-like object (perforated plate, slit plate, etc.) having a regular spray area or spray pattern formed with a plurality of holes, or a drum (perforated drum, slit drum etc.), a method of injecting water with a spray nozzle or the like, a method of forming the entangled portion (B) by switching on and off the spray of water from the spray nozzle, and a method of combining these. . According to the shape and size of the fiber web, the shape and arrangement pattern of the entangled portion (B) to be formed, etc., these methods include a method in which the spray nozzle is moved continuously or periodically, a method in which the fiber web is transferred to an endless conveyor, and the like. It is possible to appropriately select a method of continuously or periodically transporting by a belt conveyor, or a method of combining these. For example, the entangled portion (B) can be continuously formed by installing a spray nozzle in the drum described above, rotating the drum while spraying water, and transporting the fiber web. Materials constituting the plate-shaped object and the drum may be, for example, metal, plastic, wood, or the like.

When the entangled portions (A) and the entangled portions (B) form a border-like pattern in which the entangled portions (A) and the entangled portions (B) are arranged alternately with respect to the flow direction, the entangled portions (B) are arranged, for example, in a specific direction perpendicular to the flow direction. It can be formed by spraying water from a spray nozzle onto the fibrous web through a plate or drum having a slit in its width. The slit width may be, for example, 0.5 to 30 mm, preferably 1 to 20 mm, more preferably 2 to 10 mm, still more preferably 3 to 8 mm. The pitch of the slits is, for example, 2.5 mm or more, preferably 3 mm or more, more preferably 3.5 mm or more. On the other hand, the pitch of the slits may be, for example, 20 mm or less, preferably less than 20 mm, more preferably 15 mm or less, still more preferably 10 mm or less.

In the case of forming the border pattern, the entangled portion (B) sprays water by switching on and off from spray nozzles arranged linearly with respect to the flow direction, for example, while continuously moving the fiber web. It can also be formed by

When the entangled portions (B) having a specific shape form a plane grid pattern that is regularly arranged, the entangled portions (B) are, for example, a plate-like object or a drum in which a plurality of holes are regularly formed. can be formed by spraying water from a spray nozzle through the fibrous web.

The shape of the hole is not particularly limited, but may be, for example, oval, elliptical, circular, square, rectangular, etc., preferably oval. In the case of an oval shape, the length in the major axis direction is, for example, 1 to 80 mm, preferably 5 to 60 mm, more preferably 10 to 40 mm, and the length in the minor axis direction is, for example, 1 to 80 mm, preferably 3 to 40 mm. 50 mm, more preferably 5 to 30 mm. The plurality of holes may be arranged in a planar grid pattern, such as a square grid pattern, a rhombic grid pattern, a rectangular grid pattern, or the like. The pitch of the holes may be, for example, 2.5 mm or more, preferably 3 mm or more, and more preferably 3.5 mm or more. On the other hand, the pitch of the holes may be, for example, 20 mm or less, preferably less than 20 mm, more preferably 15 mm or less, even more preferably 10 mm or less.

The jet pressure of water may be, for example, 4 MPa or higher, preferably 8 MPa or higher, more preferably 10 MPa or higher, even more preferably 15 MPa or higher, and particularly preferably over 15 MPa. If the jet pressure of water is equal to or higher than the above lower limit, the fibers will be in a state of being compacted, and even if a steam jet is applied in the subsequent entangling step 2, the fibers will be fixed and will not move. However, since the coiled crimp is difficult to develop, the entangled portion (B) tends to be easily formed. On the other hand, the upper limit of the water ejection pressure may be, for example, 20 MPa or less.

The temperature of water is preferably 5 to 50°C, more preferably 10 to 40°C, still more preferably 15 to 35°C (normal temperature).

As a method of spraying or injecting water, a method of injecting water using a nozzle or the like having a regular spray area or spray pattern is preferable from the viewpoint of simplicity. Specifically, water can be sprayed onto the fibrous web transported by a belt conveyor such as an endless conveyor while the fibrous web is placed on the conveyor belt. The conveyor belt may be water permeable, and the back side of the fibrous web may also pass through the water permeable conveyor belt to inject water onto the fibrous web. When water is also sprayed from the back side of the fibrous web, it is preferable to spray water onto the fibrous web via a plate-like object or drum having a spray area or spray pattern also on the back side of the fibrous web. The fiber web may be pre-wet with a small amount of water in order to suppress scattering of the fibers due to jetting water. When transported by a conveyor, the transport speed may be, for example, 5 to 40 m/min, preferably 10 to 20 m/min.

The nozzle for spraying or injecting water uses a plate or die in which predetermined orifices are continuously arranged in the width direction according to the pattern of the entangled portion (B) to be formed, and the fiber web supplied with this orifices are arranged in the width direction of the One or more rows of orifices may be provided, and a plurality of rows may be arranged in parallel. Also, a plurality of nozzle dies having one row of orifices may be installed in parallel. The nozzle pitch may be, for example, 1.0-2.5 mm. Also, the nozzle diameter may be, for example, 0.2 to 0.5 mm.

In the entangling step 2, the fiber web is heated with high-temperature steam, and the conjugate fibers in the portion not sprayed with water in the above-described entangling step are crimped into a coil to form the entangled portion (A). become. In the high temperature steam treatment method, the fibrous web is exposed to a stream of high temperature or superheated steam (high pressure steam), which creates coil crimps in the bicomponent fibers (latently crimped fibers). Since the fiber web has air permeability, even if it is treated from one direction, high-temperature steam permeates into the interior, causing substantially uniform crimps in the thickness direction, and the fibers are evenly entangled with each other. . The temperature of the hot steam may be, for example, 50-150°C, preferably 40-130°C, more preferably 60-120°C.

The conjugate fibers in the portion not sprayed with water in the fiber web entangling step 1 shrink at the same time as the high-temperature steam treatment. Therefore, it is desirable that the fibrous web to be supplied is over-fed according to the area shrinkage rate of the intended fibrous structure immediately before being exposed to the high-temperature steam. The overfeed rate is preferably 110 to 250% with respect to the length of the target fiber structure.

A conventional steam jet device can be used to supply steam to the fibrous web. The steam injection device is preferably a device capable of spraying steam approximately uniformly over the entire width of the fiber web at a desired pressure and amount. The steam injection device may be provided only on one side of the fibrous web, or may be provided on the other side in order to steam-process the front and back of the fibrous web at once.

Since the high-temperature steam injected from the steam injection device is an air current, it enters the interior of the fiber web without significantly moving the fibers in the fiber web, unlike the hydroentanglement process or the needle punch process. Due to the entry action of the water vapor flow into the fiber web, the water vapor flow efficiently covers the surface of each fiber existing in the fiber web, enabling uniform thermal crimping. Moreover, compared with dry heat treatment, heat can be sufficiently conducted to the inside of the fiber web, so that the degree of crimping in the surface direction and the thickness direction becomes generally uniform.

As for the nozzle for injecting high-temperature steam, a plate or die in which predetermined orifices are continuously arranged in the width direction is used in the same manner as the above nozzle for hydroentanglement. They should be arranged side by side. One or more rows of orifices may be provided, and a plurality of rows may be arranged in parallel. Also, a plurality of nozzle dies having one row of orifices may be installed in parallel.

The pressure of the high-temperature steam used can be selected from the range of 0.1-2 MPa (eg, 0.2-1.5 MPa). If the steam pressure is too high, the fibers forming the fibrous web may move more than necessary, resulting in a disturbed formation or excessive entanglement of the fibers. If the pressure is too weak, the amount of heat required for developing fiber crimps cannot be applied to the fiber web, or water vapor cannot penetrate the fiber web, resulting in uneven fiber crimp development in the thickness direction. It's easy to do. The temperature of the high-temperature steam can be selected from the range of 70 to 180° C. (eg, 80 to 150° C.), although it depends on the material of the fibers and the like. The high-temperature steam treatment speed can be selected from a range of 200 m/min or less (eg, 0.1 to 100 m/min).

After the conjugate fibers in the fibrous web are crimped in this manner, moisture may remain in the fibrous structure, so a drying step for drying the fibrous structure may be provided as necessary. Drying methods include methods using drying equipment such as cylinder dryers and tenters; non-contact methods such as far-infrared irradiation, microwave irradiation, and electron beam irradiation; methods such as blowing hot air or passing hot air through it. can be mentioned.

The fiber structure of the present invention has excellent initial conformability, can be tightly wound, does not contain an adhesive, and has self-adhesion, so it is used for applications that come into contact with the human body, such as medical and sports fields. Suitable for tapes such as bandages and supporters used in Another subject of the invention is a dressing comprising the fibrous structure described above.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Each physical property value of the fiber structures obtained in Examples and Comparative Examples was measured by the following methods.
(1) Apparent ^average fiber length The surface of the fiber structure is measured with an electron microscope. 100 arbitrarily selected apparent fiber lengths were measured and the average value was obtained.
(2) Number of crimps Evaluated according to JIS L1015 "Testing methods for chemical fiber staples" (8.12.1).
(3) Fabric weight Measured in accordance with JIS L1913 "General staple fiber nonwoven fabric test method".
(4) Thickness (T _A ) of entangled portion (A) (height of convex portion)
The thickness was measured according to JIS L1913 "General short fiber nonwoven fabric test method".
(5) Thickness (T _B ) of entangled portion (B) (base height)
The thickness was measured according to JIS L1913 "General short fiber nonwoven fabric test method".
(6) Density of Entangled Portion (A) The density was calculated from the basis weight measured in (3) above and the thickness measured in (4).
(7) Density of Intertwined Portion (B) The density was calculated from the basis weight measured in (3) above and the thickness measured in (5).
(8) Area ratio of entangled portion (A) The area ratio of the entangled portion (A) existing per 0.5 cm ² of the fiber structure was determined as follows. The surface of the fibrous structure was observed over 0.5 cm ² with an electron microscope at a magnification of 300. For one field of view observed with an electron microscope, 1 is defined when only crimped fibers are visible, 0.5 when crimped fibers and other fibers are mixed, and 0 when no crimped fibers are present. The total was determined, and the total determined with respect to the observed number of fields was defined as the area ratio of the entangled portion (A).
(9) As a method for measuring the distance between the entangled portions (B), measure the distance between two points at the central portion of the entangled portion that is the furthest away using a ruler.
(10) 50% elongation recovery rate Measured in accordance with JIS L1096 "General Textile Test Methods". However, in the evaluation in the present invention, the recovery rate was uniform at an elongation of 50%, and after returning to the original position after elongation by 50%, the next operation was performed without waiting. In addition, the measurement was performed in the flow (MD) direction of the fiber structure. AG-IS manufactured by Shimadzu Corporation was used as a constant speed elongation type tensile tester.
(11) Elongation stress Measured in accordance with JIS L1096 "General Textile Testing Methods". Each elongation stress was measured at 50% and 80% elongation. AG-IS manufactured by Shimadzu Corporation was used as a constant speed elongation type tensile tester.
(12) Self-adhesiveness Curved surface sliding stress (N/50 mm) was measured by the following method. If it was 1 N/50 mm or more, it was assumed to have self-adhesiveness.

First, the fiber sheet was cut into a size of 50 mm width×600 mm length so that the MD direction was the length direction, and a sample 5 was obtained. Next, as shown in FIG. 2( a ), one end of the sample 5 was fixed with a single-sided adhesive tape 6 to a core 7 (pipe roll made of polypropylene resin with an outer diameter of 30 mm and a length of 150 mm). Using an alligator clip 8 (grip width 50 mm, 0.5 mm thick rubber sheet fixed with double-sided tape inside the mouth for use) on the other end of sample 5, uniform over the entire width of sample 5 A weight 9 of 150 g was attached so that a weight was applied to the .

Next, while the core 7 to which the sample 5 is fixed is lifted so that the sample 5 and the weight 9 are suspended, the core 7 is rotated five times so that the weight 9 does not shake greatly, and the sample 5 is wound up. 9 was lifted (see FIG. 2(b)). In this state, the contact point between the cylindrical portion of the outermost peripheral portion of the sample 5 wound around the core 7 and the planar portion of the sample 5 not wound around the core 7 (the portion of the sample 5 wound around the core 7 and the part of the sample 5 that is vertical due to the gravity of the weight 9) is set as a reference point 10, and the alligator clip 8 and the weight 9 are slowly moved so that this reference point 10 does not move and shift. Removed. Next, at a point 11 halfway (180°) along the sample 5 wound around the winding core 7 from this base point 10, the outermost peripheral portion of the sample 5 was cut with a razor blade so as not to damage the inner layer sample, A cut 12 was provided (see FIG. 3).

The curved surface sliding stress between the outermost layer portion of this sample 5 and the inner layer portion wound around the winding core 7 below (inner layer) was measured. For this measurement, a tensile tester (“Autograph” manufactured by Shimadzu Corporation) was used. The winding core 7 is fixed to a jig 13 installed on the fixed-side chuck pedestal of the tensile tester (see FIG. 4), and the end of the sample 5 (the end to which the alligator clip 8 was attached) is attached to the chuck 14 on the load cell side. and pulled at a tensile speed of 200 mm/min.
<Example 1>
As latent crimp fibers, a polyethylene terephthalate resin [component (A)] having an intrinsic viscosity of 0.65 and a modified polyethylene terephthalate resin [component (B)] obtained by copolymerizing 20 mol % of isophthalic acid and 5 mol % of diethylene glycol. Constructed side-by-side type composite staple fiber [manufactured by Kuraray Co., Ltd., "Sofit PN780", 1.7 dtex × 51 mm length, number of mechanical crimps 29 / 25 mm, number of crimps 29 / 25 mm after heat treatment at 130 ° C. × 1 minute ] was prepared. Using 100% by mass of this side-by-side type composite staple fiber, a carded web having a basis weight of 30 g/m ² was formed by a carding method.
(Entanglement step 1)
This card web is moved on a conveyor net and passed through a perforated drum having holes (elliptic shape) in an orthorhombic lattice with a long axis dimension of 50 mm, a short axis dimension of 5 mm, and a pitch of 15 mm. A water stream was sprayed at 10 MPa toward the web and the conveyor net through the fiber entanglement process.

Next, this card web was transferred to the entangling process 2 while overfeeding the web to about 200% so as not to inhibit the shrinkage in the entangling process 2 by steam.
(Entanglement step 2)
Next, the card web is introduced into a steam injection device provided on a belt conveyor, and water vapor of 0.5 MPa and a temperature of about 160° C. is jetted perpendicularly to the card web from the steam injection device to subject the card web to a steam treatment, and a latent winding is performed. A coiled crimp of the crimped fibers was developed and the fibers were entangled. This steam injection device had a nozzle installed in one of the conveyors so as to spray steam toward the card web through the conveyor belt. The hole diameter of the water vapor injection nozzle was 0.3 mm, and a device was used in which the nozzles were arranged in a row at a pitch of 2 mm along the width direction of the conveyor. The processing speed was 8.5 m/min, and the distance between the nozzle and the conveyor belt on the suction side was 7.5 mm. Finally, it was dried with hot air at 120° C. for 1 minute to obtain an elastic sheet-like fiber structure 1 .

Various measurements were performed on the obtained fiber structure 1 . Table 1 shows the results. FIG. 1 shows a schematic diagram of the arrangement pattern of the entangled portions (B) 2 in the machine direction of the obtained fiber structure 1 .

<Example 2>
A fiber structure was produced in the same manner as in Example 1, except that in the entangling step 1, the water flow was jetted at a water pressure of 20 MPa. Table 1 shows the evaluation results.

<Example 3>
In the entangling step 1, the same as Example 1 except that the long axis dimension was 50 mm, the short axis dimension was 10 mm, and the perforated drum was passed through a perforated drum having holes (oval shape) in an orthorhombic lattice with a pitch of 10 mm. Then, a fiber structure was produced. Table 1 shows the evaluation results.

<Example 4>
In the entangling step 1, the fiber structure was produced in the same manner as in Example 1 except that the fiber structure was passed through a perforated drum having border-like holes with a long axis dimension of 400 mm, a short axis dimension of 5 mm, and a pitch of 15 mm. made. Table 1 shows the evaluation results.

<Comparative Example 1>
A fiber structure was produced in the same manner as in Example 1, except that the entangling step 1 was not performed. Table 1 shows the evaluation results.

<Comparative Example 2>
Instead of performing the entangling step 1, the card web is moved on a conveyor net and passed through a perforated drum having holes (circular) in an orthorhombic lattice pattern with a diameter of 2 mmφ and a pitch of 2 mm. A water flow is sprayed at 0.8 MPa toward the web and the conveyor net from the inside of the fiber to perform an uneven distribution step of periodically forming low-density regions and high-density regions of the fibers. While transferring the card web to a belt conveyor equipped with a 76-mesh, 500-mm-wide resin endless belt, orifices with a diameter of 0.1 mm were arranged in a row at intervals of 0.6 mm in the width direction of the web. A fiber structure was produced in the same manner as in Example 1, except that water was jetted at a water pressure of 4 MPa. Table 1 shows the evaluation results.

Compared to Comparative Example 2, the fiber structures of Examples 1 to 3 had smaller stress at 50% elongation, excellent initial conformability, and excellent 50% elongation recovery rate. In addition, compared to Comparative Example 1, the fiber structures of Examples 1 to 3 have a higher stress at 80% elongation, and can be tightly wound. That is, the fiber structures of Examples 1 to 3, compared to Comparative Examples 1 and 2, had both the properties required for low elongation and high elongation in a well-balanced manner.

1 fiber structure, 2 entangled portion (B), 3 entangled portion (A), 4 distance between entangled portions (B), 5 sample, 6 single-sided adhesive tape, 7 winding core, 8 alligator clip, 9 weight, 10 base point, 11 half circle point from base point, 12 cut, 13 jig, 14 chuck.

Claims (9)

A fibrous structure comprising coiled crimped fibers (a) and non-coiled crimped fibers (b), wherein the fibrous structure comprises an entangled portion (A ) and two or more entangled portions (B) composed of non-coiled crimped fibers (b), and the distance between at least one entangled portion (B) in the machine direction of the fiber structure is , a fiber structure having an apparent average fiber length less than that of the coiled crimped fibers (a). 2. The fiber structure according to claim 1, wherein the ratio of the area of the entangled portion (A) to the surface area of the fiber structure is 20 to 85% on the surface of the fiber structure. The ratio of the thickness (T _A ) of the entangled portion (A) to the thickness (T _B ) of the entangled portion (B) is T _A /T _B =1.1 to 10, or 3. The fiber structure according to 2. The fiber structure according to any one of claims 1 to 3, wherein the stress at 50% elongation is 15 N/5 cm or less and the stress at 80% elongation is 20 N/5 cm or more in the machine direction of the fiber structure. Any one of claims 1 to 4, wherein the ratio of stress at 50% elongation to stress at 80% elongation in the machine direction of the fiber structure, stress at 80% elongation/stress at 50% elongation, is 2.7 or more. The fibrous structure described. The fiber structure according to any one of claims 1 to 5, wherein the coiled crimped fiber (a) is composed of a composite fiber in which a plurality of resins having different coefficients of thermal shrinkage or thermal expansion form a phase structure. body. The fiber structure according to any one of claims 1 to 6, which has a basis weight of 50 to 200 g/ ^m2 . A bandage comprising the fibrous structure according to any one of claims 1-7. A method for producing a fiber structure according to any one of claims 1 to 8,
1) a step of web-forming the fibers;
2) entangling portions of the web by spraying or jetting water to form entangled portions (B); and 3) heating the web with high-temperature steam to form entangled portions (A). ,Production method.

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