JP4705321B2 - Non-woven - Google Patents

Description

This invention is elastically extensible, and about good nonwoven slip against the skin.

  The elastically extensible web described in Japanese Patent Application Laid-Open No. 06-184897 (Patent Document 1) includes a fiber layer made of an elastically extensible polymer and a fiber made of an inelastically extensible polymer. It is formed by overlapping the layers.

  The elastically stretchable non-woven fabric described in JP-T-09-512313 (Patent Document 2) is also a fiber layer made of an elastically stretchable polymer and a fiber made of an inelastically stretchable polymer The layers are superimposed on each other.

  The elastically stretchable composite yarn described in Japanese Patent Laid-Open No. 04-11021 (Patent Document 3) is made of a core-sheath type composite fiber, and the core fiber is made of elastically stretchable urethane. The sheath fiber is made of inelastically stretchable polyamide.

  The stretchable fabric described in Japanese Patent Application Laid-Open No. 09-316748 (Patent Document 4) has a core made of an elastomer and a sheath made of a non-elastomeric material. The forming filament is used for the weft.

  Japanese Patent No. 3262803 (Patent Document 5) describes an invention relating to a melt-spun multicomponent thermoplastic continuous filament, a product formed therefrom, and a forming method therefor. According to this invention, splittable multicomponent thermoplastic filaments that have been extruded from an extruder and passed through a quench chamber enter the Lurgi tube. The Lurgi tube is fed with compressed air, in which the filaments are drawn and separated. Thereafter, the separated filaments are collected on a collecting surface made of a porous screen or the like to form a nonwoven fabric.

Japanese Patent Application Laid-Open No. 09-291454 (Patent Document 6) discloses an invention relating to a stretchable elastic nonwoven fabric. According to this invention, the elastic elastic nonwoven fabric is formed by using an elastic elastic conjugate fiber having a hard elastic component made of crystalline polypropylene as a first component and a thermoplastic elastomer as a second component. As this composite fiber, a side-by-side type or a sheath-and-core type is used. The composite fiber is processed into a nonwoven fabric by a spunbond method, a thermal bond method, or the like.
Japanese Patent Laid-Open No. 06-184897 JP-T 09-512313 Japanese Patent Laid-Open No. 04-11021 JP 09-316748 A Japanese Patent No. 3262803 JP 09-291454 A

  In the webs and nonwoven fabrics described in Documents 1 and 2, a fiber layer made of an elastically stretchable polymer forms the surface of the nonwoven fabric. Since fibers made of this type of polymer generally have a large coefficient of friction, the nonwoven fabric on which the fiber layer forms the surface has poor slipping when touched to the skin. Moreover, in the nonwoven fabric obtained by superimposing two fiber layers, the thickness tends to be thick.

  The composite yarns and fabrics described in References 3 and 4 are elastically stretched by using a core-sheath type composite fiber, using an elastomer for the core fiber, and using a non-elastomer for the sheath fiber. Elastomers, which are possible polymers, do not touch the skin directly. Such composite yarns and fabrics have good slippage when touching the skin. However, the sheath fibers having accordion-like wrinkles hinder the elastic contraction of the core fiber, and the amount of elastic expansion and contraction of the composite yarn and fabric is reduced. In addition, since the composite fiber has a bellows-like sheath and has a large diameter, it is difficult to obtain a soft touch peculiar to a fiber having a small fineness in these composite yarns and fabrics.

  According to document 5, a non-woven fabric is formed after a splittable multi-component thermoplastic filament is split into a plurality of thin filaments in a Lurgi tube. On the surface of this nonwoven fabric, each component in the multi-component thermoplastic filament forms a thin filament according to the proportion of the component. If one of the multicomponents is a thermoplastic elastomer, the filaments appear on the surface of the nonwoven fabric according to the proportion of the filaments made of thermoplastic elastomer in the multicomponent, and the nonwoven fabric is affected by the elastomer. On the other hand, it may be slippery.

  In Document 6, a stretchable elastic composite fiber having a hard elastic component made of polypropylene as a first component and a thermoplastic elastomer as a second component, and a stretchable elastic nonwoven fabric obtained by fusing between the entanglement points of the composite fiber, Since the surface of the composite fiber is composed of a portion occupied by polypropylene and a portion occupied by elastomer, the slippage against the skin is suppressed as compared with the case where the entire surface is occupied by the elastomer. However, if the elastomer is present on the surface of the composite fiber, it will also appear on the surface of the stretchable elastic nonwoven fabric, so that the slippage of the nonwoven fabric against the skin becomes worse. Further, in the example of this document 6, a sheath-and-core type composite fiber having a first component polypropylene as a sheath and an elastomer made of an ethylene-α-olefin copolymer as a core is disclosed. The elastic extensibility of such a composite fiber is dominated by the extensibility of the hard elastic component made of polypropylene, and the inherent extensibility of the elastomer may be suppressed.

In this invention, while making it possible to enlarge the amount of elastic expansion | extension and shrinkage | contraction, it is making the subject the provision of the nonwoven fabric which can adjust the slipperiness with respect to skin.

The present invention for solving the above-described problems is directed to an elastically stretchable first fiber formed by the first polymer and an inelastically stretchable second fiber formed by the second polymer. It is an elastically stretchable nonwoven fabric formed by fibers.

In such a nonwoven fabric, the invention is characterized as follows. The nonwoven fabric has a first surface and a second surface that are parallel to each other in the thickness direction. The second polymer has a crystallinity of 30% or less based on the DSC method, and the second fiber is the first fiber at each of the joint portions intermittently formed on the first fiber. And is separated from the first fibers between the adjacent bonding sites on the first fibers and the bonding sites. The second fibers in the separated state have a length longer than the length of the first fibers, and the number of the second fibers is formed in a ratio of 1 to 16 with respect to one first fiber. Yes. The sliding angle of at least one of the first surface and the second surface is in the range of 25 ° to 40 °, and the sliding angle is measured by a tester that attaches the nonwoven fabric between the upper surface of the plate and the lower surface of the block. The upper surface of the plate has a surface roughness specified in JIS B 0601 of 12.5 s, and the block exerts a surface pressure of 10 g / cm ² . A nonwoven fabric having such a sliding angle is suitable for use in a worn article or the like.

The present invention has the following preferred embodiments.
(1) In any one of the first and second surfaces, the first fibers are positioned on the inner side in the thickness direction, and the second fibers are positioned on the outer side in the thickness direction. , The second fibers intersect. In the non-woven fabric in which the first fiber is in such an embodiment, when this is used for a wearing article, there is generally little chance of contact between the first fiber having a rubbery touch and the skin of the wearer of the article. Become.
(2) On the surface of the first fiber, a first curved surface portion that protrudes from the central portion in the radial direction of the first fiber toward the outside of the first fiber, and a convex portion that protrudes from the outside toward the central portion. And the second curved surface portions that are alternately repeated in the circumferential direction of the first fiber, and the first curved surface portions that are located between the first curved surface portions that are adjacent to each other in the circumferential direction and the first curved surface portions. The two curved surface portions cooperate to form a groove portion extending in the length direction of the first fiber, and the second curved surface portion forms the bottom of the groove portion. In the nonwoven fabric in which the first fiber is in such an embodiment, when the first fiber is used for a worn article, only the first curved surface portion of the first fiber contacts the skin of the wearer. There are fewer opportunities for contact.
(3) The first polymer is either a thermoplastic polyurethane or a thermoplastic polyurethane containing a lubricant, and the second polymer is either a polyolefin polymer or a polyamide polymer. These polyolefin-based polymers and polyamide-based polymers are suitable for obtaining inelastically extendable second fibers.

Method for producing said first fibers which elastically extensible made of the first polymer, the inelastically formed by the extendable second fibrous elastically stretchable nonwoven fabric made of a second polymer, It is as follows .

The surface of the first fiber component of fibrous formed by the first polymer, second fiber component fibrous extending parallel to the first fiber component is formed by the second polymer is bonded in a separable By supplying a plurality of composite fibers formed in the machine direction, a web having a basis weight of 10 to 500 g / m ² made of the composite fibers is formed. In the web, a plurality of portions where the conjugate fibers are joined in an inseparable manner are intermittently formed in at least one of the machine direction and the crossing direction with respect to the machine direction. Thereafter, the web is stretched in at least one direction within an elastic deformation range of the first fiber component and at an elongation equal to or lower than the breaking elongation of the second fiber, The first fiber component and the second fiber component are separated between each other, and the second fiber component is permanently deformed. Furthermore, after that, the web is contracted by the elastic restoring force of the first fiber component, the first fiber from the first fiber component, the second fiber from the second fiber component, and the web from the web A non-woven fabric is obtained.

The manufacturing method includes the following preferred embodiments.
(1) On the surface of the first fiber component in the conjugate fiber, a first surface portion that protrudes from the center in the radial direction of the first fiber component toward the outside of the first fiber component, and from the outside The second surface portion that is convex toward the center portion alternately repeats in the circumferential direction of the first fiber component, and the first surface portions that are adjacent in the circumferential direction and the first surface portions are adjacent to each other. The second surface portion located therebetween cooperates to form a groove portion extending in the length direction of the first fiber component on the surface, and the second fiber component is in the groove portion and It extends parallel to the first fiber component.
(2) On the peripheral surface of the composite fiber, a portion of the peripheral surface composed of the second fiber component occupies 40 to 90% of the peripheral length of the composite fiber.
(3) In the composite fiber, the second fiber component is formed in a ratio of 1 to 16 with respect to one first fiber component.
(4) The first polymer is either a thermoplastic polyurethane or a thermoplastic polyurethane containing a lubricant, and the second polymer is either a polyolefin polymer or a polyamide polymer.

  In this invention, the slip angle of a nonwoven fabric is measured using the apparatus shown in FIG. Details of the measurement method are included in the description of FIG.

  Even if the nonwoven fabric according to the present invention has elastic fibers, by disposing at least one inelastic fiber having a length longer than that elastic fiber in the vicinity of one elastic fiber, The slipperiness can be adjusted to be close to that of the non-elastic fiber. In the nonwoven fabric according to the present invention, when a plurality of non-elastic fibers are arranged in the vicinity of one elastic fiber and one elastic fiber is surrounded by these non-elastic fibers, the non-woven fabric slips particularly. It will be good. The length of the non-elastic fiber is longer than the length of the elastic fiber between the portions where the non-elastic fiber is bonded to the elastic fiber, so that the elastic fiber and the nonwoven fabric are not hindered from being elastically stretched.

  According to the method for producing a nonwoven fabric according to the present invention, by separating the composite fiber in which the fibrous non-elastic fiber component is separably bonded to the surface of the fibrous elastic fiber component into the respective fiber components, the fineness is increased. It is possible to obtain a thin nonwoven fabric having a structure in which a small non-elastic fiber surrounds an elastic fiber having a large fineness and elastically expands and contracts. In the nonwoven fabric produced by such a manufacturing method, at least one of the two surfaces can be made to have a soft touch peculiar to non-elastic fibers having a small fineness, not to the touch of elastic fibers having a high fineness.

  The details of the nonwoven fabric and its manufacturing method according to the present invention will be described with reference to the accompanying drawings.

  The piece of the non-woven fabric 1 having a substantially hexahedron shown in a perspective view in FIG. 1 has an upper surface 2 and a lower surface 3 parallel to each other, and cut surfaces 4a, 4b, Side surfaces are formed by 4c and 4d. Non-woven fabric 1 includes elastic fibers 11 having elastic extensibility formed by a first thermoplastic polymer, non-elastic fibers 12 having inelastic extensibility formed by a second thermoplastic polymer, and These two fibers 11 and 12 are in contact with each other in parallel in the length direction, and have a composite fiber portion 13 joined at the contact portion. In the nonwoven fabric 1, these fibers 11, 12 and the composite fiber portion 13 are not substantially separated from each other by being welded, bonded, or mechanically entangled with each other at the plurality of joint portions 16. It is united with. The elastic fiber 11 and the non-elastic fiber 12 are formed by a method of manufacturing the nonwoven fabric 1 described later, which are fiber components 21 and 22 (see FIG. 2), which are components forming the composite fiber 13a having substantially the same structure as the composite fiber portion 13. It is formed by separating into components. In the figure, the composite fiber portion 13 exists mainly in the vicinity of the joining portion 16.

  In the nonwoven fabric 1, the fineness of the elastic fiber 11 is in the range of 0.1 to 10 dtx, the fineness of the non-elastic fiber 12 is in the range of 0.05 to 2 dtx, and is preferably made smaller than the fineness of the elastic fiber 11. ing. Except for the vicinity of the joint portion 16, there are 1 to 16 non-elastic fibers 12 around one elastic fiber 11, and these non-elastic fibers 12 are adjacent to each other on the elastic fiber 11. It extends between the bonding sites 16, for example between the illustrated bonding sites 16a and 16b. In the illustrated nonwoven fabric 1, there are three non-elastic fibers 12a, 12b, and 12c as non-elastic fibers 12 around one elastic fiber 11a (see also FIG. 5). In addition, these non-elastic fibers 12a, 12b, and 12c extend so as to branch from the elastic fiber 11a in the vicinity of the joint portions 16a and 16b. The elastic fiber 11a and the non-elastic fibers 12a, 12b, and 12c repeat such joining and branching in the length direction of the elastic fiber 11a. Between the adjacent joint portions 16a and 16b, the lengths of the non-elastic fibers 12a, 12b, and 12c are longer than the length of the elastic fibers 11a, and the elastic fibers 11a extend almost linearly. The fibers 12a, 12b, and 12c are bent or curved into various shapes. These elastic fibers 11a and inelastic fibers 12a, 12b, and 12c appear on the upper surface 2 at a ratio of approximately 1: 3. In the preferred non-woven fabric 1, the elastic fiber 11a and the non-elastic fibers 12a, 12b, 12c also appear at a ratio of 1: 3 on the lower surface 3. The ratio of the number of end portions of the elastic fiber 11 and the non-elastic fiber 12 that can be seen on the cut surface 4a of the nonwoven fabric 1 is the ratio of the number of the elastic fiber 11a and the non-elastic fibers 12a, 12b, 12c. Is almost equal to

  The use of the nonwoven fabric 1 is not particularly limited, but it is a person who wears articles such as disposable diapers, disposable pants, disposable medical gowns, etc. or daily miscellaneous goods such as disposable wipes. When it is directed to an application that touches the skin, the linear distance between adjacent joint parts 16a and 16b on one elastic fiber 11a is in the range of 0.5 to 10 mm, and the joint part 16a and It is preferable that each length along the non-elastic fibers 12a, 12b, and 12c between 16b is in the range of 1.2 to 5 times the length along the elastic fibers 11a.

  When the nonwoven fabric 1 thus formed is held in a hand and pulled in the A direction or the B direction orthogonal to the A direction, the elastic fiber 11 is elastically stretched and bent or curved. The direction of the non-elastic fiber 12 is changed so as to extend toward the A direction or the B direction. When the hand is released from the nonwoven fabric 1, the state of FIG. 1 is restored by the elastic restoring force of the elastic fiber 11. The elastic fiber 11 that elastically expands and contracts generally has a rubbery touch, but in this nonwoven fabric 1, there are a plurality of non-elastic fibers 12 surrounding the elastic fiber 11, The touch of the surfaces 2 and 3 of the non-woven fabric 1 becomes a good slip similar to the touch of the non-elastic fibers 12. Further, the slipperiness of the nonwoven fabric 1 can be adjusted by the fineness and cross-sectional shape of the non-elastic fibers 12 arranged around the elastic fibers 11, the number of non-elastic fibers 12, and the like. When the fineness of the non-elastic fiber 12 is as small as possible, for example, about 0.5 to 1.5 dtx, the surfaces 2 and 3 have flexibility in addition to smoothness.

  2 and 3 are cross-sectional photographs of the composite fiber 13a used for manufacturing the nonwoven fabric 1, and a drawing obtained by tracing the composite fiber 13a in the photograph. Each of the plurality of composite fibers 13a shown in FIG. 2 is substantially the same having a diameter of 25 to 30 microns, and is composed of one fibrous elastic fiber component 21 and the surface of the elastic fiber component 21. In addition, it is formed with three fibrous inelastic fiber components 22 that are arranged at substantially equal intervals in the circumferential direction and are detachably joined to the elastic fiber component 21. The composite fiber 13a has the same composition and substantially the same structure as the composite fiber portion 13 in FIG. 1, and includes a thermoplastic first polymer that forms the elastic fiber component 21 and the non-elastic fiber component 22, respectively. The thermoplastic second polymer can be obtained by simultaneously extruding from a nozzle of a spinning extruder based on a well-known technique. On the peripheral surface of the elastic fiber component 21, the first surface portion 51 that protrudes outward from the center portion of the elastic fiber component 21 and the first surface portion 51, opposite to the first surface portion 51, protrude from the outside toward the center portion. The second surface portion 52 is formed so as to repeat alternately in the circumferential direction of the elastic fiber component 21. The first surface portion 51 adjacent in the circumferential direction and the second surface portion 52 located between the first surface portions 51 cooperate with each other so that the second surface portion 52 becomes the bottom. 53 is formed. The groove portion 53 includes three groove portions 53 a, 53 b, and 53 c and extends in the length direction of the elastic fiber component 21. The non-elastic fiber component 22 is composed of three non-elastic fiber components 22a, 22b, and 22c located in the respective groove portions 53a, 53b, and 53c, and extends in the length direction of the elastic fiber component 21.

Examples of the first polymer used for obtaining the elastic fiber component 21 in the composite fiber 13a include thermoplastic polyurethane, thermoplastic polyurethane containing a lubricant, and other thermoplastic elastomers. An example of a second polymer used to obtain the inelastic fiber component 22 is a thermoplastic polymer that is incompatible with the first polymer and extends inelastically. The incompatibility here means that in the composite fiber 13a of FIG. 2, the bonding force of the non-elastic fiber component 22 to the elastic fiber component 21 is weak, and when the composite fiber 13a expands, the non-elastic fiber component 22 is elastic fiber. Means easy separation from component 21. Examples of the second polymer having such properties include polyolefin polymers such as polyethylene and polypropylene, and polyamide polymers such as nylon. Polypropylene can be used whether it is a homopolymer or a copolymer. However, the polypropylene preferably has a crystallinity of 30% or less based on the DSC method, more preferably a crystallinity of 20% or less, and is not regarded as a hard elastic fiber. When the first polymer used for the elastic fiber component 21 contains a lubricant such as a fatty acid amide, the elastic fiber component 21 and the non-elastic fiber component 22 can be easily separated. Specific examples of the elastic fiber component 21 include thermoplastic polyurethane having a melt viscosity of 23 to 180 × 10 ³ poises as defined in JIS K 7311. Specific examples of the non-elastic fiber component 22 include 230 ° C., 2.16 kg / There is a polypropylene with an MFR (melt flow rate) of 30 in cm ² . The weight ratio of the elastic fiber component 21 and the non-elastic fiber component 22 in the composite fiber 13a is preferably in the range of 20:80 to 90:10. In the peripheral surface of the composite fiber 13a, it is preferable that the peripheral surface portion composed of the inelastic fiber component 22 occupies 40 to 90% of the peripheral length of the composite fiber 13a. In the radial cross section of the composite fiber 13a, the cross-sectional area and shape of the elastic fiber component 21 and the non-elastic fiber component 22 are such that the fineness of the elastic fiber 11 obtained from these components 21 and 22 is 0.1 to 10 dtx. The fineness of the non-elastic fiber 12 is smaller than that of the elastic fiber 11 and is formed to be 0.05 to 2 dtx. The non-elastic fiber component 22 has a flat cross-sectional shape such as an oval, and preferably has a flat cross-sectional shape even when the non-elastic fiber 12 is formed. The non-elastic fiber 12 having a flat cross-sectional shape preferably has a major axis larger than twice the minor axis and can be bent flexibly.

The nonwoven fabric 1 of FIG. 1 is manufactured as follows using such a conjugate fiber 13a. The composite fiber 13a is preferably made of continuous fiber, and the composite fiber 13a is continuously supplied in the machine direction to form a web having a basis weight of 10 to 500 g / m ² . In the process in which the web travels in the machine direction, the composite fiber 13a is welded or entangled inseparably with each other by subjecting the web to an embossing process under heating, a process of injecting a high-pressure columnar water stream, or a hot air blowing process. 1 is formed intermittently in at least one of the machine direction and the crossing direction with respect to this direction. Next, this web is within the range of elastic deformation of the elastic fiber component 21 in at least one of the directions in which the joining sites 16 are intermittently formed, and is equal to or less than the breaking elongation of the non-elastic fiber component 22. Thus, for example, the elongation is 70% or more. Thereafter, the web is contracted by the restoring force of the elastic fiber component 21 to obtain the nonwoven fabric 1 of FIG. When the web is stretched, the elastic fiber component 21 and the non-elastic fiber component 22 of the composite fiber 13a are adjacent to each other between the adjacent joint parts 16 on the composite fiber 13a, for example, between the joint parts 16a and 16b shown in FIG. In the meantime, it is separated into one elastic fiber 11 and three inelastic fibers 12. The stretched inelastic fiber component 22 is permanently deformed to increase its length and decrease its fineness. In the obtained nonwoven fabric 1, each elastic fiber 11 contracts so as to draw a straight line or a gentle curve between adjacent joining portions 16 a and 16 b, while the non-elastic fiber 12 is elastic fiber 11. It shrinks while drawing a curve that intersects the inelastic fibers 12.

  4 and 5 show elastic fibers 11a as examples of elastic fibers 11 and non-elastic fibers 12a, 12b and 12c as examples of non-elastic fibers 12 on the upper surface 2 of the nonwoven fabric 1 of FIG. It is a figure which shows the VV cut surface in an enlarged plan view and that top view. In FIG. 4, the elastic fiber component 21 and the non-elastic fiber component 22 of the composite fiber 13 a are not separated in the vicinity of the joint portions 16 a and 16 b, and the composite fiber 13 a remains as the composite fiber portion 13. While the elastic fibers 11a extend substantially linearly between the adjacent joint portions 16a and 16b on the elastic fibers 11a generated by separation, the inelastic fibers 12a, 12b, and 12c draw curves of various shapes. It extends. The elastic fiber 11a and the non-elastic fiber 12b intersect and overlap each other, and at the intersecting portion, the elastic fiber 11a is located inside the nonwoven fabric 1 in the thickness direction, and the non-elastic fiber 12b is outside the thickness direction. Is located. In the cut surface shown in FIG. 5, the non-elastic fibers 12a, 12b, and 12c are distributed around the fiber 11a so as to surround the elastic fiber 11a.

  FIG. 6 is an enlarged perspective view of the elastic fiber 11a in FIG. On the surface of the elastic fiber 11a, a first curved surface portion 61 having a small curvature radius that protrudes outward from the center portion of the elastic fiber 11a and a second curved surface portion 62 that protrudes from the outside toward the center portion. It is formed so as to repeat alternately in the circumferential direction of the elastic fiber 11. There is a second curved surface portion 62 between the first curved surface portions 61 adjacent to each other in the circumferential direction, and the first curved surface portions 61 and the second curved surface portion 62 cooperate to make the length of the elastic fiber 11a. A groove 63 extending in the direction is formed. Each of the first curved surface portion 61, the second curved surface portion 62, and the groove portion 63 is a portion corresponding to each of the first surface portion 51, the second surface portion 52, and the groove portion 53 in the conjugate fiber 13a of FIG.

  In the nonwoven fabric 1 having the elastic fiber 11 and the non-elastic fiber 12 shown in FIGS. 4, 5, and 6, the skin is easily in contact with the non-elastic fibers 12 a, 12 b, 12 c, and is not easily in contact with the elastic fiber 11 a, The non-woven fabric 1 tends to feel close to that of the non-elastic fiber 12 having good slip. When the number of the non-elastic fibers 12 that intersect the elastic fibers 11a increases as in the non-elastic fibers 12b in FIG. 4, the elastic fibers 11a that are rubbery on the upper surface 2 of the nonwoven fabric 1 and have a poor sliding property against the skin. Since it will be in the state embedded in the non-elastic fiber 12, the tendency will become strong. Further, as shown in FIG. 6, the elastic fiber 11a is in contact with the skin 69 indicated by the phantom line mainly in the vicinity of the first curved surface portion 61 and the second curved surface portion 62. Hardly touches the skin 69. Thus, since the peripheral surface of the elastic fiber 11a touches the skin 69 is only a part of the peripheral surface and is limited to a portion having a small radius of curvature, the elastic fiber 11a has a cross section having the same cross-sectional area as that. Compared with the case where the shape is circular, the contact area with the skin 69 tends to be smaller. The smaller the contact area between the elastic fiber 11 and the skin 69, the better the slip of the nonwoven fabric 1 with respect to the skin 69. Further, when the elastic fiber 11a and the skin 69 are in contact with each other, a gap may be generated between the skin 69 and the groove 63 of the elastic fiber 11a. In the nonwoven fabric 1 in such a state, the skin can be prevented from being stuffy by flowing air through the gap. In the nonwoven fabric 1 which concerns on this invention, it can replace with the upper surface 2, and the lower surface 3 can also be made into the aspect of the upper surface 2 of FIG. 1, or these both surfaces 2 and 3 can also be made into the aspect of FIG.

  FIG. 7 is a view similar to FIG. 5 when the nonwoven fabric 1 is pulled in the direction A of FIG. When the nonwoven fabric 1 is pulled and the elastic fibers 11a extend in the direction A in FIG. 4, the non-elastic fibers 12a, 12b, and 12c in FIG. 5 move in the directions of arrows P, Q, and R, approach the elastic fibers 11a, and the fibers 11a It will be in the state of FIG. Since the degree of orientation of the inelastic fiber 12 in FIG. 7 is increased in the direction of arrow A in FIG. 4, the nonwoven fabric 1 has good sliding in the direction of arrow A.

  8 and 9 are drawings similar to FIGS. 2 and 3 showing an example of the composite fiber 13a used in the present invention. The composite fiber 13a has a diameter of about 15 microns, and is composed of an elastic fiber component 21 having a semicircular cross section and a non-elastic fiber component 22 having a similar semicircular cross section. The cross section of the composite fiber 13a is substantially circular, and the inelastic fiber component 22 appearing on the peripheral surface occupies about 50% of the peripheral length of the composite fiber 13a. Also in the nonwoven fabric 1 obtained by extending and shrinking the web made of the composite fiber 13a, the length of the non-elastic fiber generated from the non-elastic fiber component 22 is longer than the length of the elastic fiber generated from the elastic fiber component 21. . When such an inelastic fiber is bent or curved so as to intersect with the elastic fiber, the contact between the elastic fiber and the skin is hindered. Even if it is not as much as 1 non-woven fabric 1, the sliding against the skin is good.

  In this invention, the nonwoven fabric 1 is manufactured using the web which consists of the composite fiber 13a in which the elastic fiber component 21 has the groove part 53 shown by FIG. 3, and the non-elastic fiber component 22 exists in the groove part 53. Then, the fineness of the non-elastic fiber 12 can be easily reduced as compared with the fineness of the elastic fiber 11.

  FIG. 10 is a diagram illustrating a cross-sectional shape of the conjugate fiber 13a. The composite fiber 13a of (a) has a cross-sectional shape different from that of the composite fiber 13a of FIG. 9, and a single groove 53 is formed in the elastic fiber component 21. In (b), two grooves 53 are formed in the elastic fiber component 21. In (c), four groove portions 53 are formed in the elastic fiber component 21. In the present invention, 1 to 16 groove portions 53 can be formed in the elastic fiber component 21 in this manner.

FIG. 11 is a side view of a tester 70 used for evaluating the smoothness of the nonwoven fabric in the present invention. The tester 70 includes a plate 71 capable of increasing the inclination angle α with respect to the horizontal plane at a constant speed using a motor 73, and a block 72 for attaching a nonwoven fabric to be evaluated. The upper surface of the plate 71 is formed of stainless steel having a surface roughness specified in JIS B 0601 of 12.5 s. Block 72, a surface pressure of 10 g / cm ² is formed by the weight of the stainless steel so as to act on the nonwoven fabric 1. The nonwoven fabric is attached to the block 72 so as to cover the entire lower surface of the block 72. The plate 71 on which the block 72 is placed is swung around the shaft 74 so that the inclination angle α with respect to the horizontal plane increases at a speed of 2 ° / sec, and the inclination when the block 72 starts to slide on the upper surface of the plate 71. The angle α is obtained, and the value at that time is defined as the slip angle α _S. As the value of the slip angle alpha _S decreases, the nonwoven fabric is slippery against the skin. The sliding angle α _S of men's and women's underwear shirts and pants made of 100% cotton measured by the tester 70 is in the range of about 21 ° to 25 °.

Table 1, the nonwoven fabric of Example obtained by using composite fibers 13a in FIG. 2 and 3 according to the present invention, the slip angle alpha _S with nonwoven fabric as a comparative example is shown. The non-woven fabric in the examples is obtained by subjecting a web having a basis weight of 50 g / m ² to a heat embossing treatment in the machine direction and the direction crossing the direction. The composite fiber 13a is made of thermoplastic polyurethane and polypropylene, and the weight ratio of these both is in the range of 84.4: 15.6 to 67.9: 32.1. Among them, the polypropylene accounted for approximately 70 to 90%. The nonwoven fabric of the comparative example is obtained by subjecting a web made of thermoplastic polyurethane fiber or polypropylene fiber to a web having a basis weight of 50 g / m ² and the same hot embossing treatment as the web in the examples. In the heat embossing process in the example and the comparative example, a plurality of heated embossed areas of 0.3 mm ² were formed with a pitch of ² mm in the machine direction and the crossing direction for each web. As is apparent from Table 1, the sliding angle α _s of the nonwoven fabric 1 varies depending on the proportion of polypropylene as the inelastic fiber component 22 in the peripheral length of the composite fiber 13a. In other words, in this invention, the sliding angle α _s of the nonwoven fabric 1 can be adjusted by the ratio of the non-elastic fiber component 22 in the peripheral length of the composite fiber 13a. When the nonwoven fabric 1 is used for a wearing article, it is preferable to adjust the sliding angle α _S of the upper surface 2 and / or the lower surface 3 in the range of 25 ° to 40 °.

In this invention, in order to adjust the sliding angle α _S of the nonwoven fabric 1, in addition to those described as examples in Table 1 as the composite fiber 13a, the weight ratio of thermoplastic polyurethane to polypropylene is 20:80 to Those in the 90:10 range can be used. Moreover, what has the ratio of the polypropylene which occupies for the periphery length in the range of 40 to 90% can be used as the composite fiber 13a.

  The nonwoven fabric which concerns on this invention can be used for manufacture of disposable wearing articles etc. Such a nonwoven fabric can be produced by the production method according to the present invention.

The perspective view of a nonwoven fabric. A photograph showing a cross section of a composite fiber. The figure which traced the composite fiber of FIG. The elements on larger scale of FIG. The figure which shows the VV line | wire cut surface of FIG. The elements on larger scale of FIG. The figure similar to FIG. 5 when a nonwoven fabric is pulled. The same photograph as FIG. 2 which shows an example of an embodiment. The figure similar to FIG. 3 which shows an example of an embodiment. The figure which shows the composite fiber from which cross-sectional shape differs by (a), (b), (c). Side view of a tester.

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric 2 Surface 3 Surface 11, 11a 1st fiber (elastic fiber)
12, 12a, 12b, 12c Second fiber (inelastic fiber)
13a Composite fiber 16 Joining portion 21 First fiber component 22 Second fiber component

Claims (4)

In an elastically stretchable nonwoven formed by an elastically stretchable first fiber formed by a first polymer and an inelastically stretchable second fiber formed by a second polymer,
The nonwoven fabric has a first surface and a second surface parallel to each other in the thickness direction, and the second polymer has a crystallinity of 30% or less based on a DSC method, and the second fiber Are joined to the first fiber at each of the joint parts intermittently formed on the first fiber, and the first part between the joint part and the joint part adjacent to each other on the first fiber. In the state separated from the fiber, the length of the second fiber in the separated state is longer than the length of the first fiber, and the number of the second fibers is 1 with respect to the first fiber. The sliding angle of at least one of the first surface and the second surface is in the range of 25 ° to 40 °, and the sliding angle is between the upper surface of the plate and the lower surface of the block. By a tester that attaches the nonwoven fabric to The non-woven fabric is characterized in that the upper surface of the plate has a surface roughness defined by JIS B 0601 of 12.5 s and the block exerts a surface pressure of 10 g / cm ² . In any one of the first and second surfaces, the first fiber is positioned inside the thickness direction, and the second fiber is positioned outside the thickness direction. The nonwoven fabric according to claim 1, wherein the fibers intersect. On the surface of the first fiber, a first curved surface portion that protrudes from the central portion in the radial direction of the first fiber toward the outside of the first fiber, and a first convex portion that protrudes from the outside toward the central portion. The second curved surface portion that is alternately repeated in the circumferential direction of the first fiber and that is positioned between the first curved surface portions adjacent to each other in the circumferential direction and the first curved surface portion. The non-woven fabric according to claim 1 or 2, wherein a groove portion extending in a length direction of the first fiber is formed in cooperation with the first fiber, and the second curved surface portion forms a bottom of the groove portion. The first polymer is either a thermoplastic polyurethane or a thermoplastic polyurethane containing a lubricant, and the second polymer is either a polyolefin polymer or a polyamide polymer. Non-woven fabric.

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