JP2016079529A - Nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric with improved touch.SOLUTION: A nonwoven fabric 1 according to this invention has multiple fusion parts 12 formed by thermal fusion bonding of intersections between constituent fibers 11. The constituent fibers 11 contain high-elongation fiber. A piece of constituent fiber 11 has a large diameter part 17 with large fiber diameter, which is sandwiched between two small diameter parts 16, 16 with small fiber diameter, between adjacent fusion parts 12, 12. A change point 18 from the small diameter part 16 adjacent to the fusion part 12 to the large diameter part 17 is arranged within a range of 1/3 of a space T between the adjacent fusion parts 12, 12 from the fusion part 12.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a nonwoven fabric.

  The applicant previously arranged a web containing low-stretch non-elastic fibers on one side of the web containing elastic fibers, and subjected the air-through hot air treatment to these webs to intersect the fibers. Proposed a technique relating to a non-woven fabric produced by stretching a fiber sheet formed by integrating these webs to stretch the low-elasticity non-elastic fiber, and then releasing the stretching of the fiber sheet. (Patent Document 1). In the method for producing a nonwoven fabric described in Patent Document 1, when a fiber sheet is stretched, a stretching apparatus including a pair of concavo-convex rolls that can be engaged with each other is used. The technique of extending | stretching using such an extending | stretching apparatus provided with such a pair of uneven | corrugated roll is described also in patent documents 2-4 other than patent document 1, for example.

JP 2008-7924 A JP 2013-189745 A JP 2010-119861 A JP 2012-67426 A

  The nonwoven fabric manufactured by the manufacturing method described in Patent Document 1 is formed to include elastic fibers and non-elastic fibers whose thickness along the longitudinal direction is not uniform. Thus, when the thickness of the non-elastic fiber is not uniform, the touch is good. However, there was a need to improve the feel.

  Moreover, in patent document 2, it is essential to use a stretchable fiber, ie, an elastic fiber. And in patent document 2, although there exists description of making the fiber diameter of a fiber thin with an extending | stretching apparatus, the part with a thin fiber diameter and the part with a large fiber diameter are formed in one fiber, and fiber There is no description on what position the boundary between the narrow diameter part and the thick part is arranged.

  Moreover, in patent document 3, nothing is described regarding using a high elongation fiber. In addition, Patent Document 3 does not describe anything about reducing the fiber diameter of the fiber by a drawing device, and includes a portion having a small fiber diameter and a portion having a large fiber diameter in one fiber. No assumptions are made about the formation.

  Moreover, in patent document 4, nothing is described regarding using a high elongation fiber. In addition, Patent Document 4 describes that the fiber sheath diameter is reduced by performing a core-sheath peeling using a stretching device, but in what position the boundary between the thin fiber portion and the thick portion is disposed. Is not described at all.

  Therefore, the subject of this invention is providing the nonwoven fabric which can eliminate the fault which the prior art mentioned above has.

  The present invention is a nonwoven fabric provided with a plurality of fusion parts formed by heat-sealing the intersections of the constituent fibers, and the constituent fibers include high elongation fibers and focus on one of the constituent fibers. The constituent fiber has a large-diameter portion with a large fiber diameter sandwiched between two small-diameter portions with a small fiber diameter between the adjacent fusion portions, and the fusion portion The present invention provides a nonwoven fabric in which the change point from the adjacent small-diameter portion to the large-diameter portion is arranged within 1/3 of the interval between the adjacent fused portions from the fused portion.

  According to the present invention, the touch can be further improved.

FIG. 1 is a perspective view showing an embodiment of the nonwoven fabric of the present invention. FIG. 2 is a schematic diagram showing a cross section in the thickness direction of the nonwoven fabric shown in FIG. FIG. 3 is a diagram illustrating a state in which the constituent fibers constituting the nonwoven fabric shown in FIG. 1 are fixed at the heat-sealing portion. FIG. 4 is a schematic view showing a manufacturing apparatus suitably used for manufacturing the nonwoven fabric shown in FIG. FIG. 5 is a schematic diagram illustrating an extending portion included in the manufacturing apparatus illustrated in FIG. 4. 6 is a cross-sectional view taken along line VI-VI shown in FIG. Fig.7 (a)-FIG.7 (c) are explanatory drawings explaining a mode that a several small diameter part and a large diameter part are formed in one constituent fiber between adjacent fusion | melting parts.

The present invention will be described below based on preferred embodiments with reference to the drawings.
FIG. 1 shows a perspective view of a nonwoven fabric 1 (hereinafter also referred to as “nonwoven fabric 1”) which is an embodiment of the present invention. FIG. 2 is a schematic diagram showing a cross section in the thickness direction of the nonwoven fabric 1 shown in FIG. FIG. 3 is an enlarged schematic view of the constituent fibers 11 of the nonwoven fabric 1 shown in FIG. As shown in FIG. 1, the nonwoven fabric 1 is a nonwoven fabric provided with a plurality of fusion portions 12 (see FIG. 3) formed by thermally fusing the intersections of the constituent fibers 11. And in this embodiment, as shown in FIG. 1, the nonwoven fabric 1 is a nonwoven fabric with a concavo-convex structure in which streaky ridges 13 and ridges 14 extending in one direction (X direction) are alternately arranged. is there. Specifically, as shown in FIG. 2, the nonwoven fabric 1 is adjacent to a plurality of ridges 13 in which the cross-sectional shapes of both the front and back surfaces a and b are convex upward in the thickness direction (Z direction). It has the concave line part 14 located between the convex line parts 13 and 13 which fit. The concave stripe part 14 has a concave shape in which the cross-sectional shapes of the front and back surfaces a and b are both upward in the thickness direction (Z direction) of the nonwoven fabric. In other words, as for the concave strip part 14, the cross-sectional shape of front and back both surfaces a and b has comprised the convex shape toward the downward direction of the thickness direction (Z direction) of a nonwoven fabric. Each of the plurality of ridges 13 extends continuously in one direction (X direction) of the nonwoven fabric 1, and each of the plurality of ridges 14 extends continuously in one direction X of the nonwoven fabric 1. I am doing. The ridges 13 and the ridges 14 are parallel to each other and are alternately arranged in a direction (Y direction) orthogonal to the one direction (X direction).

  In addition, the nonwoven fabric 1 has the top part area | region 13a, the bottom part area | region 13b, and the side part area | region 13c located between these 13a, 13b in the cross sectional view of the nonwoven fabric 1 as shown in FIG. And the top part of the protruding item | line part 13 is formed from the top part area | region 13a, and the bottom part of the grooved part 14 is formed from the bottom part area | region 13b. The top region 13a, the bottom region 13b, and the side region 13c extend continuously in one direction (X direction) of the nonwoven fabric 1. As shown in FIG. 2, the top region 13a, the bottom region 13b, and the side region 13c are cross-sectional views of the nonwoven fabric 1, and the thickness in the Z direction of the nonwoven fabric 1 is divided into three equal parts. Are divided into a top region 13a, a central region in the thickness direction (Z direction) as a side region 13c, and a lower region in the thickness direction (Z direction) as a bottom region 13b. The said division is measured by the following method.

[Method of dividing top region 13a, bottom region 13b, and side region 13c]
The non-woven fabric 1 was cut in the Y direction using a feather razor (part number FAS-10, manufactured by Feather Safety Razor Co., Ltd.) and measured with a scanning electron microscope (JCM-5100 (trade name) manufactured by JEOL Ltd.). The portion to be expanded is enlarged to a size (10 to 100 times) that can be sufficiently measured and measured, the thickness in the Z direction of the nonwoven fabric 1 is divided into three equal parts, and the upper portion in the thickness direction (Z direction) is the top region 13a. The central portion in the thickness direction (Z direction) is distinguished as a side region 13c, and the lower portion in the thickness direction (Z direction) is distinguished as a bottom region 13b.
When analyzing from a commercially available diaper or the like, a cold spray is sprayed on the target diaper or the like to solidify the hot melt adhesive. Then, each material is carefully peeled off to obtain a target nonwoven fabric, which is cut and measured as described above.

  As will be described later, the nonwoven fabric 1 is manufactured by subjecting the fiber sheet 1a to a concavo-convex process using a pair of concavo-convex rolls 401 and 402 meshing with each other. One direction (X direction) of the nonwoven fabric 1 described above is the same direction as the machine direction (MD, flow direction) when the nonwoven fabric 1 is manufactured by performing uneven processing on the fiber sheet 1a. The direction (Y direction) orthogonal to the direction (X direction) is the same direction as the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction).

  The constituent fiber 11 of the nonwoven fabric 1 includes high elongation fibers. Here, the high elongation fiber included in the constituent fiber 11 means not only a fiber having a high elongation at the raw material fiber stage, but also a fiber having a high elongation at the stage of the produced nonwoven fabric 1. As the “high elongation fiber”, excluding stretchable fibers that have elasticity (elastomer) and expand and contract, for example, as described in paragraph [0033] of JP 2010-168715, melt spinning is performed at a low speed to form a composite After obtaining the fiber, the heat-extensible fiber, which is obtained by changing the crystal state of the resin by heating and / or crimping without stretching, or polypropylene or polyethylene Fibers manufactured under relatively low spinning speeds using resins such as polyethylene, polypropylene-polypropylene copolymers with low crystallinity, or fibers manufactured by dry blending polyethylene into polypropylene and spinning, etc. Is mentioned. Among these fibers, the high elongation fiber is preferably a core-sheath type composite fiber having heat-fusibility. The core-sheath type composite fiber may be a concentric core-sheath type, an eccentric core-sheath type, a side-by-side type, or a deformed type, but is preferably a concentric core-sheath type. Whatever form the fiber takes, from the viewpoint of producing a nonwoven fabric that is soft and soft to the touch, the fineness of the high elongation fiber may be 1.0 dtex or more at the raw material stage. Preferably, it is 2.0 dtex or more, more preferably 10.0 dtex or less, more preferably 8.0 dtex or less, specifically, 1.0 dtex or more and 10.0 dtex or less. Preferably, it is 2.0 dtex or more and 8.0 dtex or less.

  The constituent fibers 11 of the nonwoven fabric 1 may be configured to include other fibers in addition to the high elongation fibers, but are preferably composed only of inelastic fibers, and are composed only of high elongation fibers. More preferably. Other fibers include, for example, a non-heat-extensible core-sheath-type heat-fusible composite fiber containing two components having different melting points, or a fiber that does not inherently have heat-fusibility ( Examples thereof include natural fibers such as cotton and pulp, rayon and acetate fibers). When the nonwoven fabric 10 includes other fibers in addition to the high elongation fibers, the proportion of the high elongation fibers in the nonwoven fabric 10 is preferably 50% by mass or more, and more preferably 80% by mass or more. And preferably 100% by mass or less, more preferably 100% by mass or less, specifically preferably 50% by mass or more and 100% by mass or less, and more preferably 80% by mass. % Or more and 100% by mass or less is preferable.

  The heat-extensible fiber, which is an example of a high-stretch fiber, is a composite fiber that has been subjected to an unstretched or weakly stretched treatment at the raw material stage. For example, a first resin component that constitutes a core portion and a sheath portion And a second resin component containing a polyethylene resin, the first resin component having a higher melting point than the second resin component. A 1st resin component is a component which expresses the heat | fever extensibility of this fiber, and a 2nd resin component is a component which expresses heat-fusibility. The melting points of the first resin component and the second resin component were determined by thermal analysis of a finely cut fiber sample (sample weight 2 mg) using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.) at a heating rate of 10 ° C./min. The melting peak temperature of each resin is measured and defined by the melting peak temperature. When the melting point of the second resin component cannot be clearly measured by this method, the resin is defined as “resin having no melting point”. In this case, the temperature at which the second resin component is fused to such an extent that the strength of the fusion point of the fiber can be measured is used as the temperature at which the molecular flow of the second resin component begins, and this is used instead of the melting point.

As above-mentioned, as a 2nd resin component which comprises a sheath part, the polyethylene resin is included. Examples of the polyethylene resin include low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE). In particular, a high density polyethylene having a density of 0.935 g / cm ³ or more and 0.965 g / cm ³ or less is preferable. The second resin component constituting the sheath is preferably a polyethylene resin alone, but other resins can also be blended. Other resins to be blended include polypropylene resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and the like. However, as for the 2nd resin component which comprises a sheath part, it is preferable that 50 mass% or more in the resin component of a sheath part is 70 to 100 mass% especially polyethylene resin. The polyethylene resin preferably has a crystallite size of 10 nm or more and 20 nm or less, and more preferably 11.5 nm or more and 18 nm or less.

  As a 1st resin component which comprises a core part, the resin component whose melting | fusing point is higher than the polyethylene resin which is a constituent resin of a sheath part can be especially used without a restriction | limiting. Examples of the resin component constituting the core include polyolefin resins such as polypropylene (PP) (excluding polyethylene resin), polyester resins such as polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Furthermore, polyamide-based polymers, copolymers having two or more resin components, and the like can also be used. A plurality of types of resins can be blended and used. In this case, the melting point of the core is the melting point of the resin having the highest melting point. Since the production of the nonwoven fabric becomes easy, the difference (the former-the latter) between the melting point of the first resin component constituting the core part and the melting point of the second resin component constituting the sheath part is 20 ° C. or higher. It is preferable that it is 150 degrees C or less.

  The preferred orientation index of the first resin component in the thermally stretchable fiber, which is an example of a high elongation fiber, is naturally different depending on the resin used. For example, when the first resin component is a polypropylene resin, the orientation index is 60% or less. More preferably, it is 40% or less, More preferably, it is 25% or less. When the first resin component is polyester, the orientation index is preferably 25% or less, more preferably 20% or less, and still more preferably 10% or less. On the other hand, the second resin component preferably has an orientation index of 5% or more, more preferably 15% or more, and still more preferably 30% or more. The orientation index is an index of the degree of orientation of the polymer chain of the resin constituting the fiber.

  The orientation index of the first resin component and the second resin component is determined by the method described in paragraphs [0027] to [0029] of JP2010-168715A. Moreover, the method in which each resin component in the heat-extensible fiber achieves the orientation index as described above is described in paragraphs [0033] to [0036] of JP-A No. 2010-168715.

  Further, the elongation of the high elongation fiber is preferably 100% or more at the raw material stage, more preferably 200% or more, still more preferably 250% or more, and 800% or less. It is preferably 500% or less, more preferably 400% or less, specifically preferably 100% or more and 800% or less, more preferably 200% or more and 500% or less, Preferably they are 250% or more and 400% or less. By using a high elongation fiber having an elongation in this range, the fiber is successfully stretched in a stretching apparatus, and a change point 18 from a small diameter portion 16 to a large diameter portion 17 described later becomes a fusion portion 12. Adjacent and good touch.

  The elongation of the high elongation fiber conforms to JISL-1015, and the measurement is based on the measurement environment temperature and humidity of 20 ± 2 ° C, 65 ± 2% RH, the tensile tester gripping distance of 20mm, and the tensile speed of 20mm / min. And In addition, when collecting fibers from an already manufactured non-woven fabric and measuring the elongation, when the gripping interval cannot be 20 mm, that is, when the length of the fiber to be measured is less than 20 mm, the gripping interval is set. Measure by setting to 10 mm or 5 mm.

  The ratio (mass ratio, the former: latter) of the first resin component and the second resin component in the high elongation fiber is 10:90 to 90:10, particularly 20:80 to 80:20, especially in the raw material stage. It is preferable that it is 50: 50-70: 30. As the fiber length of the high elongation fiber, one having an appropriate length is used according to the method for producing the nonwoven fabric. For example, when the nonwoven fabric is manufactured by the card method as described later, the fiber length is preferably about 30 to 70 mm.

  The fiber diameter of the high elongation fiber is appropriately selected depending on the specific use of the nonwoven fabric at the raw material stage. When a nonwoven fabric is used as a constituent member of an absorbent article such as a surface sheet of an absorbent article, it is preferable to use one having a thickness of 10 μm or more, particularly preferably 15 μm or more, and one having a thickness of 35 μm or less. It is preferable to use a material having a thickness of 30 μm or less, and specifically, a material having a thickness of 10 μm to 35 μm, particularly 15 μm to 30 μm is preferable. The fiber diameter is measured by the following method.

[Measurement of fiber diameter]
As the fiber diameter of the fiber, the diameter (μm) of the fiber is measured by observing the cross section of the fiber at 200 to 800 times using a scanning electron microscope (JCM-5100 manufactured by JEOL Ltd.). The cross section of the fiber is obtained by cutting the fiber using a feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.). For each extracted fiber, the fiber diameter when approximated to a circle is measured at five locations, and the average value of the five measured values is taken as the fiber diameter.

  In the raw material stage, in the case of using a heat-extensible fiber, which is an example of a high-stretch fiber, in addition to the above-described heat-extensible fiber, Japanese Patent No. 4131852, Japanese Patent Laid-Open No. 2005-350836, Japanese Patent Laid-Open No. 2007 The fibers described in JP-303035, JP2007-204899, JP2007-204901, JP2007-204902, and the like can also be used.

.
As shown in FIG. 3, the nonwoven fabric of the present invention focuses on one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, and the constituent fiber 11 is between adjacent fusion portions 12, 12. In addition, a large-diameter portion 17 having a large fiber diameter sandwiched between two small-diameter portions 16 and 16 having a small fiber diameter is provided. Specifically, as shown in FIG. 3, paying attention to one of the constituent fibers 11 of the constituent fibers 11 of the nonwoven fabric 1, a fusion formed by heat-sealing the intersection with the other constituent fibers 11. A small diameter portion 16 having a small fiber diameter extends from the landing portion 12 with substantially the same fiber diameter. Then, paying attention to the single constituent fiber 11, the large-diameter portion 17 having a fiber diameter larger than that of the small-diameter portion 16 between the small-diameter portions 16 and 16 extending from the adjacent fusion portions 12 and 12. Are extended with substantially the same fiber diameter. Specifically, the non-woven fabric 1 focuses on one constituent fiber 11 and moves from one fused part 12 to the other fused part 12 of the adjacent fused parts 12, 12. It has constituent fibers 11 arranged in the order of a small diameter portion 16 on the side of the attachment portion 12, one large diameter portion 17, and a small diameter portion 16 on the side of the other fusion portion 12. In addition, as shown in FIG. 3, the nonwoven fabric 1 focuses on one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, and has a large diameter portion 17 between the adjacent fusion portions 12, 12. The constituent fiber 11 is provided with a plurality of (two in the nonwoven fabric 1). Specifically, the non-woven fabric 1 focuses on one constituent fiber 11 and moves from one fused part 12 to the other fused part 12 of the adjacent fused parts 12, 12. Constituent fibers arranged in the order of the small-diameter portion 16 on the bonding portion 12 side, the first large-diameter portion 17, the small-diameter portion 16, the second large-diameter portion 17, and the small-diameter portion 16 on the other fused portion 12 side. 11. As described above, the low-rigidity small-diameter portion 16 is adjacent to the fused portion 12 where the rigidity of the nonwoven fabric 1 is increased, so that the flexibility of the nonwoven fabric 1 is improved and the touch is improved. Moreover, the softness | flexibility of the nonwoven fabric 1 improves further and the touch becomes still more favorable, so that the small diameter part 16 with low rigidity is provided in the component fiber 11 in multiple numbers. The nonwoven fabric 1 pays attention to one constituent fiber 11, and preferably has one large-diameter portion 17 between adjacent fused portions 12, 12 from the viewpoint of improving the touch and reducing the strength of the nonwoven fabric. More, more preferably 1 or more, and preferably 5 or less, more preferably 3 or less, specifically preferably 1 or more and 5 or less, more preferably 1 or more and 3 Has less than one.

The ratio (L ₁₆ / L ₁₇ ) of the fiber diameter (diameter L ₁₆ ) of the small diameter part 16 to the fiber diameter (diameter L ₁₇ ) of the large diameter part 17 is preferably 0.5 or more, more preferably 0.55 or more. And preferably it is 0.8 or less, More preferably, it is 0.7 or less, Specifically, Preferably it is 0.5 or more and 0.8 or less, More preferably, it is 0.55 or more and 0.7 or less. Specifically, the fiber diameter (diameter L ₁₆ ) of the small-diameter portion 16 is preferably 5 μm or more, more preferably 6.5 μm or more, particularly preferably 7.5 μm or more from the viewpoint of improving the touch and reducing the strength of the nonwoven fabric. And preferably 28 μm or less, more preferably 20 μm or less, particularly preferably 16 μm or less, specifically preferably 5 μm or more and 28 μm or less, more preferably 6.5 μm or more and 20 μm or less, particularly preferably 7. It is 5 μm or more and 16 μm or less. The fiber diameter (diameter L ₁₇ ) of the large diameter portion 17 is preferably 10 μm or more, more preferably 13 μm or more, particularly preferably 15 μm or more, preferably 35 μm or less, more preferably 25 μm or less, from the viewpoint of improving the touch. The thickness is particularly preferably 20 μm or less, specifically, preferably 10 μm or more and 35 μm or less, more preferably 13 μm or more and 25 μm or less, and particularly preferably 15 μm or more and 20 μm or less.
The fiber diameters (the diameters L ₁₆ and L ₁₇ ) of the small diameter part 16 and the large diameter part 17 are measured in the same manner as the fiber diameter measurement described above.

  In addition, as shown in FIG. 3, the nonwoven fabric of the present invention pays attention to one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, and a small diameter portion 16 to a large diameter portion 17 adjacent to the fused portion 12. The change point 18 is arranged within a range of ３ of the interval T between the fusion parts 12, 12 adjacent to the fusion part 12. Here, the change point 18 of the nonwoven fabric of the present invention is continuously from the small diameter portion 16 extending with a small fiber diameter to the large diameter portion 17 extending with a fiber diameter larger than the small diameter portion 16. It means a portion where the fiber diameter changes extremely without including a gradually changing portion or a portion that continuously changes over a plurality of stages. When the one constituent fiber 11 is a core-sheath type composite fiber, the change point 18 of the nonwoven fabric of the present invention is the first resin component constituting the core part and the second resin constituting the sheath part. It does not include a state in which the fiber diameter is changed by peeling between the components, and it means a part where the fiber diameter is changed by stretching.

  Further, the fact that the changing point 18 is arranged within a range of 1/3 of the interval T between the adjacent fused portions 12 and 12 from the fused portion 12 means that the constituent fibers 11 of the nonwoven fabric 1 are randomly extracted. As shown in FIG. 3, the constituent fiber 11 is made of JCM-5100 (trade name) manufactured by JEOL Ltd. as a scanning electron microscope. Enlarge it so that it can be observed (100 to 300 times). Next, the interval T between the centers of the adjacent fused portions 12 and 12 is divided into three equal parts, and the region AT on the side of one fused portion 12, the region BT on the side of the other fused portion 12, and the center region CT Break down. This means that the change point 18 is arranged in the area AT or the area BT. Further, the non-woven fabric 1 in which the changing point 18 is disposed within a range of 1/3 of the interval T between the adjacent fused portions 12, 12 from the fused portion 12 is the number of the constituent fibers 11 of the non-woven fabric 1 20. When extracted randomly, the constituent fiber 11 in which the change point 18 is arranged in the region AT or the region BT means a nonwoven fabric in which at least one of the 20 constituent fibers 11 is present. Specifically, from the viewpoint of improving touch, it is preferably 1 or more, more preferably 5 or more, and particularly preferably 10 or more.

  As will be described later, the nonwoven fabric 1 of the present embodiment extends not only the side region 13c but also the top region 13a that is the top of the ridge 13 and the bottom region 13b that is the bottom of the recess 14 by stretching, The fiber density of the whole nonwoven fabric is lower than the raw material nonwoven fabric before stretching. Thereby, the liquid permeability and air permeability of the nonwoven fabric 1 are improved. Among the top region 13a, the bottom region 13b, and the side region 13c, the side region 13c is particularly easy to be stretched and the fiber density is likely to decrease. In the side region 13c, liquid permeability and air permeability are particularly good. It has improved.

  The nonwoven fabric 1 of the present embodiment is formed such that the fiber density of the side region 13c is smaller than the fiber density of the top region 13a that is the top of the ridge 13 and the fiber density of the bottom region 13b that is the bottom of the recess 14. Has been. Here, the fiber density is the mass of the fiber per unit volume of the nonwoven fabric 1. High fiber density means that the amount of fibers present per unit volume of the nonwoven fabric 1 is large and the distance between fibers is small. Low fiber density means that the amount of fibers present per unit volume of the nonwoven fabric 1 is small and the distance between fibers is large. In addition, the site | part with a high fiber density has high capillary force, and the site | part with a low fiber density has low capillary force.

  As shown in FIG. 2, when the nonwoven fabric 1 is viewed in cross-section, the nonwoven fabric 1 is a fiber in a side region 13 c between the top of the ridge 13 (top region 13 a) and the bottom of the recess 14 (bottom region 13 b). The density is the smallest. Accordingly, in the side region 13c, the amount of fibers present per unit volume of the nonwoven fabric 1 is the smallest and the inter-fiber distance is the largest. As a whole, the nonwoven fabric 1 has improved air permeability and liquid permeability. improves. Furthermore, when the fiber density of the side region 13c is formed to be the smallest, the ridge portion 13 can easily follow the movement of the wearer's skin, and good skin contact can be realized. In order to give such a fiber density to the side region 13c, the nonwoven fabric 1 may be manufactured according to the manufacturing method described later.

The ratio (D ₁₅ / D ₁₃ , D ₁₅ / D ₁₄ ) of the fiber density (D ₁₅ ) of the side region 13c to the fiber density (D ₁₃ ) in the top region 13a or the fiber density (D ₁₄ ) in the bottom region 13b. ) Is preferably 0.15 or more, more preferably 0.2 or more, and preferably 0.9 or less, more preferably 0.8 or less, and specifically preferably 0.15 or more. 0.9 or less, more preferably 0.2 or more and 0.8 or less. The specific value of the fiber density of the nonwoven fabric 1 is such that the fiber density (D ₁₃ ) in the top region 13a is preferably 80 / mm ² or more, more preferably 90 / mm ² or more, and Preferably it is 200 / mm ² or less, more preferably 180 / mm ² or less, specifically, preferably 80 / mm ² or more and 200 / mm ² or less, more preferably 90 / mm ² or more. 180 pieces / mm ² or less. Also, the fiber density _{(D 14)} of the bottom area 13b, preferably 80 present / mm ² or more, more preferably 90 present / mm ² or more, and preferably 200 present / mm ² or less, more preferably 180 / mm ² or less, specifically, preferably 80 / mm ² or more and 200 / mm ² or less, more preferably 90 / mm ² or more and 180 / mm ² or less. The fiber density of the side region 13c _{(D 15)} is preferably 30 present / mm ² or more, more preferably 40 present / mm ² or more, and preferably 80 present / mm ² or less, more preferably 70 / mm ² or less, specifically, preferably 30 / mm ² or more and 80 / mm ² or less, more preferably 40 / mm ² or more and 70 / mm ² or less. The fiber density of the top region 13 a is measured at a position near the top of the ridge 13. The fiber density of the bottom region 13b is measured at a position near the bottom point of the concave strip portion 14. The method for measuring the fiber density is as follows.

[Measuring method of fiber density in top region 13a, bottom region 13b or side region 13c]
The nonwoven fabric was cut using a feather razor (part number FAS-10, manufactured by Feather Safety Razor Co., Ltd.), and the fiber density in the top area 13a was obtained by dividing the thickness of the cut surface of the nonwoven fabric into three equal parts in the Z direction. The vicinity of the top of the ridge 13 that is the upper part is magnified and observed using a scanning electron microscope (adjusted to a magnification capable of measuring 30 to 60 fiber cross-sections; 150 to 500 times), and per fixed area (0.5 mm). ² ) Count the number of cross-sections of the fibers cut by the cut surface. Next, it converts into the number of cross sections of the fiber per 1 mm < ² >, and makes this the fiber density in the top region 13a. The measurement is performed at three locations, and the average is the fiber density of the sample. Similarly, the fiber density in the bottom region 13b is obtained by measuring the vicinity of the bottom point of the concave portion 14 which is a lower portion when the thickness of the cut surface of the nonwoven fabric is equally divided into three in the Z direction. Similarly, the fiber density of the side region 13c is determined by measuring the central part when the thickness of the cut surface of the nonwoven fabric is equally divided into three in the Z direction. As a scanning electron microscope, JCM-5100 (trade name) manufactured by JEOL Ltd. is used.

Further, in the nonwoven fabric 1 of the present embodiment, the number of fibers having the change points 18 in the constituent fibers constituting the side regions 13c is the number of fibers having the change points 18 in the constituent fibers constituting the top region 13a and the bottom region 13b. More are formed. Thereby, the top region 13a can easily follow the movement of the wearer's skin, and good skin contact can be realized. The side region 13c with respect to the number of fibers having the change point 18 in the constituent fibers constituting the top region 13a (N ₁₃ ) or the number of fibers having the change point 18 in the component fibers constituting the bottom region 13b (N ₁₄ ) The ratio (N ₁₅ / N ₁₃ , N ₁₅ / N ₁₄ ) of the number (N ₁₅ ) of fibers having the change point 18 in the constituent fibers constituting is preferably 2 or more, more preferably 5 or more, and preferably Is 20 or less, more preferably 20 or less. Specifically, it is preferably 2 or more and 20 or less, more preferably 5 or more and 20 or less. Moreover, regarding the specific value of the number of fibers having the change point 18 of the nonwoven fabric 1, the number (N ₁₃ ) of fibers having the change point 18 in the constituent fibers constituting the top region 13a is preferably one or more, and further Preferably it is 5 or more, and preferably 15 or less, more preferably 15 or less, specifically, preferably 1 or more and 15 or less, more preferably 5 or more and 15 or less. . The number (N ₁₄ ) of fibers having the change point 18 in the constituent fibers constituting the bottom region 13b is preferably 1 or more, more preferably 5 or more, and preferably 15 or less, more preferably Is 15 or less, and specifically, preferably 1 or more and 15 or less, more preferably 5 or more and 15 or less. The number (N ₁₅ ) of fibers having the change point 18 in the constituent fibers constituting the side region 13c is preferably 5 or more, more preferably 10 or more, and preferably 20 or less, The number is preferably 20 or less, specifically, preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less. The method for measuring the number of fibers having the change point 18 is as follows.

[Measurement method of the number of fibers having the change point 18 in the constituent fibers constituting the top region 13a, the bottom region 13b, or the side region 13c]
As for the number of fibers having the change point 18 in the constituent fibers 11 constituting the top region 13a, scanning electrons are scanned around the apex of the ridge 13 which is the upper part when the thickness of the nonwoven fabric is equally divided into three in the Z direction. Using a microscope, magnified observation (adjusted to a magnification capable of measuring 30 to 60 fiber cross-sections; 50 to 500 times), randomly extracted 20 constituent fibers 11 constituting the top region 13a, and 20 constituent fibers 11 The number of fibers having the change point 18 in the is counted. When there are one or more change points 18 between the fused portions, the number of fibers having the change points 18 is set, and when there are a plurality of change points 18, the number is also set to one. This is the number of fibers having the change point 18 in the constituent fibers constituting the top region 13a. The measurement is performed at three places, and the average is the number of fibers having the change point 18 in the constituent fibers constituting the top region 13a of the sample. Similarly, regarding the number of fibers having the change point 18 in the constituent fibers 11 constituting the bottom region 13b, the vicinity of the bottom point of the concave portion 14 which is a lower portion when the thickness of the nonwoven fabric is equally divided into three in the Z direction. Determine by measuring. Similarly, the number of fibers having the change point 18 in the constituent fibers 11 constituting the side region 13c is obtained by measuring the central portion when the thickness of the nonwoven fabric is equally divided into three in the Z direction. As a scanning electron microscope, JCM-5100 (trade name) manufactured by JEOL Ltd. is used.

  The nonwoven fabric 1 of this embodiment is a disposable diaper which has the surface sheet arrange | positioned at the skin opposing surface side, the back sheet arrange | positioned at the non-skin opposing surface side, and the absorber interposed between both said sheets, for example. Or it is used for absorbent articles, such as a sanitary napkin. In particular, among the constituent members of the absorbent article, the surface sheet is formed of the nonwoven fabric 1 or a liquid permeable sublayer disposed between the surface sheet and the absorbent body is formed of the nonwoven fabric 1. Can be. If the said surface sheet is formed with the nonwoven fabric 1, since the nonwoven fabric 1 is a nonwoven fabric of a concavo-convex structure, a contact area rate with skin will become low and it will become difficult to rub further. Moreover, when the said surface sheet or the said sublayer is formed with the nonwoven fabric 1, since the nonwoven fabric 1 is a nonwoven fabric of a concavo-convex structure, compression resistance improves, a feeling of cushion improves, and the return of body fluid can be prevented.

The thickness of the nonwoven fabric 1, the entire thickness of when the side view of the nonwoven fabric 1 and the sheet thickness T _S, the local thickness of the nonwoven fabric 1 that is curved to the irregularities and the layer thickness T _L. Sheet thickness _{T S} is may be adjusted as appropriate depending on the application, when used as a topsheet or sublayer of the absorbent article is preferably at least 0.5 mm, more preferably at least 1 mm, and preferably 7mm or less, 5 mm or less More specifically, 0.5 mm or more and 7 mm or less are preferable, and 1 mm or more and 5 mm or less are more preferable. By setting it as this range, the bodily fluid absorption speed | velocity at the time of use is quick, the liquid return from an absorber is suppressed, and also moderate cushioning property is realizable.

The layer thickness _TL may be different at each site in the nonwoven fabric 1 and may be appropriately adjusted depending on the application. When used as a surface sheet or sublayer of an absorbent article, the layer thickness T _L1 of the top region 13a is preferably 0.1 mm or more, more preferably 0.2 mm or more, and 3.0 mm or less. Is preferably 2.0 mm or less, specifically 0.1 mm or more and 3.0 mm or less, more preferably 0.2 mm or more and 2.0 mm or less. The layer thickness T _L2 of the bottom region 13b is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 3.0 mm or less, more preferably 2.0 mm or less. Is preferably from 0.1 mm to 3.0 mm, more preferably from 0.2 mm to 2.0 mm. The layer thickness T _L3 of the side region 13c is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 3.0 mm or less, more preferably 2.0 mm or less. Specifically, it is preferably from 0.1 mm to 3.0 mm, and more preferably from 0.2 mm to 2.0 mm. By setting it as this range, the bodily fluid absorption speed | velocity at the time of use is quick, the liquid return from an absorber is suppressed, and also moderate cushioning property is realizable.

The sheet thickness T _S and the layer thickness T _L are measured by the following methods.
Method of measuring the thickness of the sheet T _S is in a state of applying a load of 0.05kPa nonwoven 1 is measured using a thickness gauge. A laser displacement meter manufactured by OMRON Corporation is used for the thickness measuring instrument. Thickness is measured at 10 points, and the average value is calculated as the thickness.
Layer thickness T _L of assay, by expanding the cross section of the sheet by Keyence digital microscope VHX-900 by about 20 times, to measure the thickness of each layer.

  When the nonwoven fabric 1 is viewed in plan, the pitch between the top regions 13a adjacent to each other in the Y direction may be appropriately adjusted depending on the application, and is preferably 1 mm or more when used as a surface sheet or sublayer of an absorbent article. 5 mm or more is more preferable, 15 mm or less is preferable, 10 mm or less is more preferable, specifically, 1 mm or more and 15 mm or less is preferable, and 1.5 mm or more and 10 mm or less is more preferable.

The basis weight of the nonwoven fabric 1 depends on the specific use of the nonwoven fabric 1, but when used as a surface sheet or sublayer of an absorbent article, the average value of the entire sheet is preferably 15 g / m ² or more, and 20 g / m ^2. m ² or more is more preferable, and 50 g / m ² or less is preferable, 40 g / m ² or less is more preferable, specifically, 15 g / m ² or more and 50 g / m ² or less is preferable, and 20 g / m ² or more and 40 g. / M ² or less is more preferable.

  Further, a small amount of fiber treatment agent such as fiber colorant, antistatic property agent, lubricant, hydrophilic agent may be attached to the surface of the constituent fiber 11 of the nonwoven fabric 1 at the raw material stage.

  As a method for attaching the fiber treatment agent to the surface of the constituent fiber 11, various known methods can be employed without any particular limitation. For example, application by spraying, application by a slot coater, application by roll transfer, immersion in a fiber treatment agent, and the like can be mentioned. These treatments may be performed on the fibers before being made into a web, or after the fibers are made into a web by various methods. However, it is necessary to perform the process before the hot air blowing process described later. The fiber having the fiber treatment agent attached to the surface is dried at a temperature sufficiently lower than the melting point of the polyethylene resin (for example, 120 ° C. or less) by, for example, a hot air blowing type dryer.

  The nonwoven fabric of the present invention includes a fusion process in which a fiber sheet is formed by thermally fusing intersections of constituent fibers of a fiber web containing high elongation fibers at a fusion part, and the fiber sheet is stretched in one direction. It is manufactured by the manufacturing method of a nonwoven fabric provided with an extending process. One embodiment of the method for producing a nonwoven fabric of the present invention will be described with reference to FIG. FIG. 4 schematically shows a preferable manufacturing apparatus 100 used in the method for manufacturing the nonwoven fabric 1. The manufacturing apparatus 100 is suitably used for manufacturing an air-through nonwoven fabric. The manufacturing apparatus 100 includes a web forming unit 200, a hot air processing unit 300, and an extending unit 400 in this order from the upstream side to the downstream side of the manufacturing process.

  As shown in FIG. 4, the web forming unit 200 includes a web forming apparatus 201. A card machine is used as the web forming apparatus 201. As a card machine, the thing normally used in the technical field of an absorbent article can be used without a restriction | limiting in particular. Depending on the specific use of the nonwoven fabric 1, another web manufacturing apparatus, such as an airlaid apparatus, can be used instead of the card machine.

  As shown in FIG. 4, the hot air processing unit 300 includes a hood 301. Inside the hood 301, hot air can be blown by an air-through method. The hot air processing unit 300 includes an endless conveyor belt 302 made of a breathable net. The conveyor belt 302 circulates in the hood 301. The conveyor belt 302 is made of a resin such as polyethylene terephthalate or a metal.

  The temperature of the hot air blown in the hood 301 and the heat treatment time are preferably adjusted so that the intersections of the high elongation fibers included in the constituent fibers 11 of the fiber web 10 are thermally fused. Specifically, the temperature of the hot air is preferably adjusted to a temperature higher by 0 ° C. to 30 ° C. than the melting point of the resin having the lowest melting point among the constituent fibers 11 of the fiber web 10. The heat treatment time is preferably adjusted to 1 to 5 seconds according to the temperature of the hot air. Moreover, it is preferable that the wind speed of a hot air is about 0.3 m / sec-1.5 m / sec from a viewpoint of encouraging the further entanglement of the constituent fibers 11. Moreover, it is preferable that a conveyance speed is about 5 m / min-100 m / min.

  The extending | stretching part 400 is provided with a pair of uneven | corrugated roll 401,402 which can mesh | engage as shown in FIG. 4, FIG. The pair of concave and convex rolls 401 and 402 are formed so as to be heatable, and are formed by alternately arranging large-diameter convex portions 403 and 404 and small-diameter concave portions (not shown) in the roll axis direction. The uneven rolls 401 and 402 may or may not be heated, but the heating temperature when heating the uneven rolls 401 and 402 makes it easy to stretch the high elongation fibers included in the constituent fibers 11 of the fiber sheet 1a described later. From the viewpoint, it is preferable to be not less than the glass transition point of the resin having the highest glass transition point in the high elongation fiber and not more than the melting point of the resin having the lowest melting point in the high elongation fiber. More preferably, the temperature is 10 ° C. higher than the glass transition point of the fiber and 10 ° C. lower than the melting point, more preferably 20 ° C. higher than the glass transition point of the fiber and 20 ° C. lower than the melting point. It is. For example, when the core / sheath fiber is used as the fiber, PET (core) having a glass transition point of 67 ° C. and a melting point of 258 ° C./PE (sheath) having a glass transition point of −20 ° C. and a melting point of 135 ° C. is used. The temperature is preferably 67 ° C. or higher and 135 ° C. or lower, more preferably 77 ° C. or higher and 125 ° C. or lower, still more preferably 87 ° C. or higher and 115 ° C. or lower.

  In the manufacturing apparatus 100, as shown in FIG. 6, the interval (pitch) between the large-diameter convex portions 403, 403 adjacent to each other in the roll axis direction of the uneven roll 401 and the roll axis direction of the uneven roll 402 are adjacent to each other. The spacing (pitch) between the large-diameter convex portions 404 and 404 is the same spacing (pitch) w, and the spacing (pitch) w is such that the high elongation fibers included in the constituent fibers 11 of the fiber sheet 1a are successfully used in the stretching apparatus. From the viewpoint of extending and extending the previously described change point from the small-diameter portion to the large-diameter portion adjacent to the fused portion and improving the touch, it is preferably 1 mm or more, particularly preferably 1.5 mm or more. And preferably 10 mm or less, particularly preferably 8 mm or less, specifically, preferably 1 mm or more and 10 mm or less, particularly preferably 1.5 mm or more and 8 mm or less. That. From the same viewpoint, as shown in FIG. 6, the pushing amount t of the pair of concavo-convex rolls 401 and 402 (the distance between the apex of the large-diameter convex portion 403 and the apex of the large-diameter convex portion 404 adjacent in the roll axis direction) is The thickness is preferably 1 mm or more, particularly preferably 1.2 mm or more, and preferably 3 mm or less, particularly preferably 2.5 mm or less, and specifically preferably 1 mm or more and 3 mm or less. Especially preferably, it is 1.2 mm or more and 2.5 mm or less. From the same viewpoint, the mechanical stretch ratio is preferably 1.5 times or more, particularly preferably 1.7 times or more, and preferably 3.0 times or less, particularly preferably 2.8. More specifically, it is preferably 1.5 times or more and 3.0 times or less, and particularly preferably 1.7 times or more and 2.8 times or less.

The manufacturing method of the nonwoven fabric 1 using the manufacturing apparatus 100 which has the above structure is demonstrated.
First, as shown in FIG. 4, in the web forming part 200, the short web-like constituent fibers 11 having high elongation fibers are used as raw materials, and the fiber web 10 is formed by the web forming apparatus 201 which is a card machine ( Web forming step). The fiber web 10 manufactured by the web forming apparatus 201 is in a state where the constituent fibers 11 are loosely entangled with each other, and has not yet achieved shape retention as a sheet.

  Next, as shown in FIG. 4, the fiber sheet 1 a is formed by thermally fusing the intersections of the constituent fibers 11 of the fiber web 10 including the high elongation fibers at the fusion part 12 (fusing step). Specifically, the fiber web 10 is conveyed onto the conveyor belt 302, and hot air is blown in an air-through manner while passing through the hood 301 by the hot air processing unit 300. When hot air is thus blown by the air-through method, the constituent fibers 11 of the fiber web 10 are further entangled, and at the same time, the intersection of the entangled fibers is thermally fused (see FIG. 7 (a)) to form a sheet. A fiber sheet 1a having a shape-retaining property is manufactured.

  Next, as shown in FIG. 4, the fused fiber web 1a is stretched in one direction (stretching step). Specifically, the fused fiber web 1a having a shape-retaining property as a sheet is conveyed between a pair of concavo-convex rolls 401 and 402, as shown in FIGS. 7 (a) to 7 (c). In addition, the fiber web 1a is stretched, and a large fiber diameter is sandwiched between two small-diameter portions 16 and 16 having a small fiber diameter in one constituent fiber 11 between adjacent fusion portions 12 and 12. The large diameter portion 17 is formed, and the change point 18 from the small diameter portion 16 to the large diameter portion 17 is set to 1/3 of the interval T between the fusion portions 12, 12 adjacent to the fusion portion 12. Form within the range. Specifically, as shown in FIG. 7A, the fiber sheet 1a in which the intersections of the constituent fibers 11 are thermally fused at the fusion part 12 is conveyed between a pair of concave and convex rolls 401 and 402. Then, the fiber web 1a is stretched in the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction). When the fiber sheet 1a is stretched in the orthogonal direction (CD, roll axis direction), the adjacent fused portions 12, 12 fixing the constituent fibers 11 shown in FIG. Is actively stretched in the orthogonal direction (CD, roll axis direction). In particular, as shown in FIG. 7B, local contraction is likely to occur first in the vicinity of each fusion part 12 that fixes the constituent fibers 11, and 1 between the adjacent fusion parts 12, 12. With respect to the constituent fiber 11, two small-diameter portions 16, 16 are formed at both ends, and a portion sandwiched between the two small-diameter portions 16, 16 becomes a large-diameter portion 17. A large-diameter portion 17 sandwiched between 16 is formed. In this way, local contraction is likely to occur in the vicinity of each fusion part 12, so that the change point 18 from the small diameter part 16 to the large diameter part 17 is adjacent to the fusion part 12 adjacent to the fusion part 12. It is formed within a range of 1/3 of the interval T between the 12 pieces.

  Then, with respect to one constituent fiber 11 between some adjacent fused portions 12 and 12, as shown in FIG. 7 (c), in a state where there is a room for expansion (extension margin), It is stretched in the orthogonal direction (CD, roll axis direction), the large diameter portion 17 between the adjacent fused portions 12, 12 is stretched, and the small diameter portion 16 is formed in the large diameter portion 17. Become.

  As mentioned above, according to the manufacturing method of the nonwoven fabric 1 using the manufacturing apparatus 100, the nonwoven fabric 1 provided with the constituent fiber 11 shown in FIG. 3 can be manufactured efficiently continuously. As shown in FIG. 4, the manufactured nonwoven fabric 1 is once wound up and stored in the form of a roll, and then is unwound from the roll and used. Or in the post-process line of the manufacturing apparatus 100 of the nonwoven fabric 1, a process is given and the target product is manufactured continuously.

  As shown in FIG. 3, the nonwoven fabric 1 manufactured as described above pays attention to one constituent fiber 11 among the constituent fibers 11, and the small diameter portion 16 adjacent to the fused portion 12 to the large diameter portion 17. Since the change point 18 is arranged within a range of ３ of the interval T between the adjacent fused portions 12, 12 from the fused portion 12, it is soft and good in terms of touch. In particular, if a plurality of small-diameter portions 16 are formed between the adjacent fused portions 12 and 12 while paying attention to one constituent fiber 11, the touch is further improved. From the viewpoint of easily exhibiting such an effect, the constituent fibers 11 are preferably made of only high elongation fibers.

  If elastic fibers are contained in the constituent fibers 11, the nonwoven fabric is stretched while being contracted. Therefore, even if the manufacturing method of the nonwoven fabric 1 and the mechanical stretch ratio are the same, the fiber diameter hardly changes. Therefore, the change point 18 which is a part where the fiber diameter changes extremely is difficult when the elastic fiber is contained in the constituent fiber 11, and the part which changes gradually from the small diameter part 16 to the large diameter part 17 continuously. Is easily formed. The continuously and gradually changing portion formed in this way is not necessarily stretched locally near the fusion point because it contains elastic fibers, and is observed randomly rather than near the fusion point. Become so. In addition, it is preferable that the constituent fibers 11 do not include elastic fibers from the viewpoint of further improving the touch.

  Moreover, the nonwoven fabric 1 is a nonwoven fabric of uneven structure, and the fiber density of the side part area | region 13c is formed smaller than the fiber density of the top part area | region 13a, and the fiber density of the bottom part area | region 13b. Therefore, since the interfiber distance of the side area 13c is wider than the interfiber distance of the top area 13a and the bottom area 13b, the air permeability and liquid permeability of the nonwoven fabric 1 as a whole are improved. Furthermore, when the fiber density of the side region 13c is formed to be the smallest, the ridge portion 13 can easily follow the movement of the wearer's skin, and good skin contact can be realized.

  Moreover, the nonwoven fabric 1 is a nonwoven fabric with a concavo-convex structure, and the number of change points 18 of one constituent fiber 11 constituting the side region 13c is changed by one constituent fiber 11 constituting the top region 13a. More than the number of the change points 18 which the number of the points 18 and the one component fiber 11 which comprises the bottom region 13b have are formed. Therefore, it becomes easy for the ridge 13 to follow the movement of the wearer's skin, and there is an effect of realizing good skin contact.

The nonwoven fabric of this invention is not restrict | limited to the nonwoven fabric 1 of the above-mentioned this embodiment at all, and can be changed suitably.
Moreover, the manufacturing method of the nonwoven fabric of this invention is not restrict | limited at all to the manufacturing method of the above-mentioned embodiment, It can change suitably.

  For example, as shown in FIG. 1, the nonwoven fabric 1 is a nonwoven fabric having a concavo-convex structure in which streaky ridges 13 and ridges 14 extending in one direction (X direction) are alternately arranged. It may be a non-woven fabric having a three-dimensional concavo-convex structure that is arranged at regular intervals so as to form rows intermittently in each direction of the X direction and the Y direction and forms a staggered arrangement pattern. Further, from the viewpoint of improving the shape retention of the concavo-convex structure, the concavo-convex structure non-woven fabric may be disposed on another non-woven fabric and bonded, or the concavo-convex structure non-woven fabric may be embossed. Moreover, the nonwoven fabric 1 may be a nonwoven fabric with a flat structure instead of the uneven structure.

  Moreover, according to the manufacturing method of the nonwoven fabric 1 using the manufacturing apparatus 100 mentioned above, although the fiber web 1a is extended | stretched in the orthogonal direction (CD, roll axial direction) orthogonal to a machine direction (MD, flow direction). The film may be stretched in the machine direction (MD, flow direction). Thus, when extending | stretching to a machine direction (MD, a flow direction), the convex part with which a pair of uneven | corrugated roll 401,402 which meshes | engages mutually should just be distribute | arranged to the surrounding surface so that a rotating shaft direction may be followed.

  The following nonwoven fabric is further disclosed regarding the embodiment mentioned above.

<1>
A non-woven fabric provided with a plurality of fusion parts formed by heat-sealing the intersections of the constituent fibers,
The constituent fibers include high elongation fibers,
Paying attention to one of the constituent fibers, the constituent fiber has a large diameter portion having a large fiber diameter sandwiched between two small diameter portions having a small fiber diameter between the adjacent fused portions. And
A non-woven fabric in which a changing point from the small-diameter portion adjacent to the fused portion to the large-diameter portion is arranged within a range of 1/3 of the interval between the fused portions adjacent to the fused portion.

<2>
The ratio (L ₁₆ / L ₁₇ ) of the fiber diameter (diameter L ₁₆ ) of the small diameter portion to the fiber diameter (diameter L ₁₇ ) of the large diameter portion is preferably 0.5 or more, more preferably 0.55 or more, And it is preferably 0.8 or less, more preferably 0.7 or less, specifically, preferably 0.5 or more and 0.8 or less, more preferably 0.55 or more and 0.7 or less. Non-woven fabric according to 1>.
<3>
The fiber diameter (diameter L ₁₆ ) of the small diameter portion is preferably 5 μm or more, more preferably 6.5 μm or more, particularly preferably 7.5 μm or more, and preferably 28 μm or less, more preferably 20 μm or less, particularly Preferably, it is 16 μm or less, specifically, preferably 5 μm or more and 28 μm or less, more preferably 6.5 μm or more and 20 μm or less, and particularly preferably 7.5 μm or more and 16 μm or less. Any of the above <1> to <3> Or the nonwoven fabric according to 1.
<4>
The fiber diameter (diameter L ₁₇ ) of the large diameter portion is preferably 10 μm or more, more preferably 13 μm or more, particularly preferably 15 μm or more, preferably 35 μm or less, more preferably 25 μm or less, particularly preferably 20 μm or less. Specifically, the nonwoven fabric according to any one of <1> to <3>, which is preferably 10 μm or more and 35 μm or less, more preferably 13 μm or more and 25 μm or less, and particularly preferably 15 μm or more and 20 μm or less.
<5>
The change point is the nonwoven fabric according to any one of <1> to <4>, wherein the fiber diameter is changed by stretching.
<6>
The nonwoven fabric has one or more, preferably 5 or more, more preferably 10 or more of the constituent fibers having the change point in the 20 constituent fibers, any one of <1> to <5>. The nonwoven fabric described in 1.
<7>
The non-woven fabric is a non-woven fabric having a concavo-convex structure in which streaky ridges and ridges extending in one direction are alternately arranged,
The non-woven fabric has a top region, a bottom region, and a side region located therebetween,
The top of the ridge is formed from the top region, the bottom of the ridge is formed from the bottom region,
The side region with respect to the number (N ₁₃ ) of fibers having the change point in the constituent fibers constituting the top region, or the number (N ₁₄ ) of fibers having the change point in the constituent fibers constituting the bottom region The ratio (N ₁₅ / N ₁₃ , N ₁₅ / N ₁₄ ) of the number of fibers (N ₁₅ ) having the change point in the constituent fibers constituting the wall portion between and is preferably 2 or more, more preferably 5 Any of the above <1> to <6>, preferably 20 or less, more preferably 20 or less, specifically preferably 2 or more and 20 or less, more preferably 5 or more and 20 or less. Or the nonwoven fabric according to 1.
<8>
The number (N ₁₃ ) of fibers having the change point in the constituent fibers constituting the top region is preferably 1 or more, more preferably 5 or more, and preferably 15 or less, more preferably 15 The absorbent article according to the above <7>, which is not more than this, specifically preferably not less than 1 and not more than 15 and more preferably not less than 5 and not more than 15.
<9>
The number (N ₁₄ ) of fibers having the change point in the constituent fibers constituting the bottom region is preferably 1 or more, more preferably 5 or more, and preferably 15 or less, more preferably 15 The non-woven fabric according to the above <7> or <8>, which is not more than this, specifically preferably not less than 1 and not more than 15 and more preferably not less than 5 and not more than 15.
<10>
The number (N ₁₅ ) of fibers having the change point in the constituent fibers constituting the side region is preferably 5 or more, more preferably 10 or more, and preferably 20 or less, more preferably The non-woven fabric according to any one of <7> to <9>, which is 20 or less, specifically, preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less.
<11>
The high elongation fiber means not only a fiber having a high elongation at the raw material fiber stage, but also a fiber having a high elongation at the stage of the produced nonwoven fabric as described in <1> to <10>. The nonwoven fabric of any one.

<12>
The said constituent fiber is a nonwoven fabric any one of said <1>-<11> which consists only of an inelastic fiber.
<13>
As the high elongation fiber, except for elastic fiber that has elasticity (elastomer) and expands and contracts, it is melt-spun at low speed to obtain a composite fiber, and then heat treatment and / or crimping without performing a drawing process. A heat-extensible fiber whose length changes by changing the crystalline state of the resin by heating obtained by performing the treatment, or a fiber produced under a relatively low spinning speed using a resin such as polypropylene or polyethylene, Or the nonwoven fabric in any one of said <1>-<12> with which the fiber etc. which were produced by dry-blending and spinning polyethylene in a polyethylene-polypropylene copolymer or polypropylene with low crystallinity are mentioned. .
<14>
The fineness of the high elongation fiber is preferably 1.0 dtex or more, more preferably 2.0 dtex or more, and preferably 10.0 dtex or less at the raw material stage, and 8.0 dtex or less. The non-woven fabric according to any one of <1> to <13>, more preferably 1.0 dtex or more and 10.0 dtex or less, and more preferably 2.0 dtex or more and 8.0 dtex or less. .
<15>
The proportion of high elongation fibers in the nonwoven fabric is preferably 50% by mass or more, more preferably 80% by mass or more, and preferably 100% by mass or less, more preferably 100% by mass or less. Preferably, the nonwoven fabric according to any one of <1> to <14>, which is preferably 50% by mass or more and 100% by mass or less, and preferably 80% by mass or more and 100% by mass or less.
<16>
The elongation of the high elongation fiber is preferably 100% or more at the raw material stage, more preferably 200% or more, still more preferably 250% or more, and 800% or less. More preferably 500% or less, still more preferably 400% or less, specifically 100% to 800%, preferably 200% to 500%, more preferably 250% to 400%. The nonwoven fabric according to any one of <1> to <15>, which is the following.
<17>
The nonwoven fabric according to any one of <1> to <16>, wherein a plurality of the large-diameter portions are arranged between the adjacent fused portions, paying attention to one of the constituent fibers.
<18>
Focusing on one of the constituent fibers, <1> to <1>, wherein the large-diameter portion is provided between 1 and 5 or less, preferably 1 or more and 3 or less between the adjacent fused portions. The nonwoven fabric according to any one of <17>.

<19>
The non-woven fabric according to any one of <1> to <18>, wherein the non-woven fabric is a non-woven fabric having a concavo-convex structure in which streaky ridges and ridges extending in one direction are alternately arranged.
<20>
The non-woven fabric has a top region, a bottom region, and a side region located therebetween,
The top of the ridge is formed from the top region, the bottom of the ridge is formed from the bottom region,
The nonwoven fabric according to <19>, wherein the fiber density in the side region is smaller than the fiber density in the top region and the fiber density in the bottom region.
<21>
The non-woven fabric is a non-woven fabric having a concavo-convex structure in which streaky ridges and ridges extending in one direction are alternately arranged,
The non-woven fabric has a top region, a bottom region, and a side region located therebetween,
The top of the ridge is formed from the top region, the bottom of the ridge is formed from the bottom region,
Ratio (D ₁₅ / D ₁₃ ) of fiber density (D ₁₅ ) of the wall portion between the bottom region and the fiber density (D ₁₃ ) in the top region or the fiber density (D ₁₄ ) in the bottom region , D ₁₅ / D ₁₄ ) is preferably 0.15 or more, more preferably 0.2 or more, and preferably 0.9 or less, more preferably 0.8 or less. Specifically, The nonwoven fabric according to any one of <1> to <20>, which is 0.15 to 0.9, preferably 0.2 to 0.8.
<22>
Fiber density at the top region _{(D 13)} is preferably 80 present / mm ² or more, more preferably 90 present / mm ² or more, and preferably 200 present / mm ² or less, more preferably 180 lines / Mm ² or less, specifically, 80 / mm ² or more and 200 / mm ² or less, preferably 90 / mm ² or more and 180 / mm ² or less.
<23>
Fiber density at the bottom region _{(D 14)} is preferably 80 present / mm ² or more, more preferably 90 present / mm ² or more, and preferably 200 present / mm ² or less, more preferably 180 lines / mm ² or less, specifically, 80 present / mm ² or more 200 present / mm ² or less, preferably 90 present / mm ² or more 180 lines / mm ² or less is the <21> or <22> The nonwoven fabric described.
<24>
The fiber density (D ₁₅ ) in the bottom region is preferably 30 fibers / mm ² or more, more preferably 40 fibers / mm ² or more, and preferably 80 fibers / mm ² or less, more preferably 70 fibers / mm ^2. and mm ^{2 or} less, specifically, 30 present / mm ² or more eighty / mm ² or less, either preferably at forty / mm ² or more 70 yarns / mm ² or less wherein the <21> - <23> Or the nonwoven fabric according to 1.
<25>
The number of fibers having change points in the constituent fibers constituting the side region, the number of fibers having change points in the constituent fibers constituting the top region, and the change point in the constituent fibers constituting the bottom region The nonwoven fabric according to any one of the above <20> to <24>, which is more than the number of.

<26>
A fusing step of forming a fiber sheet by thermally fusing the intersections of the constituent fibers of the fiber web containing high elongation fibers at the fusing portion;
A method for producing a nonwoven fabric comprising a stretching step of stretching the fiber sheet in one direction,
In the stretching step, the fiber sheet is stretched, and the fiber having a large fiber diameter is sandwiched between two small-diameter portions having a small fiber diameter in one constituent fiber between the adjacent fused portions. A method for producing a nonwoven fabric, wherein a diameter portion is formed, and a change point from the small diameter portion to the large diameter portion is formed within a range of 1/3 of an interval between the fusion portions adjacent to the fusion portion.
<27>
The manufacturing apparatus used in the method for manufacturing the nonwoven fabric includes a stretching section,
The extending portion includes a pair of first concavo-convex rolls and second concavo-convex rolls that can be engaged with each other,
The interval (pitch) w between large-diameter convex portions adjacent to each other in the roll axis direction of the first concave-convex roll and the interval (pitch) w between large-diameter convex portions adjacent to each other in the roll axis direction of the second concave-convex roll are: It is preferably 1 mm or more, particularly preferably 1.5 mm or more, and preferably 10 mm or less, particularly preferably 8 mm or less, specifically 1 mm or more and 10 mm or less, preferably 1.5 mm or more. The manufacturing method of the nonwoven fabric as described in said <26> which is 8 mm or less.
<28>
The pushing amount t of the first concavo-convex roll and the second concavo-convex roll (the interval between the vertex of the large-diameter convex portion of the first concavo-convex roll adjacent to the roll axis direction and the vertex of the large-diameter convex portion of the second concavo-convex roll) is , Preferably 1 mm or more, particularly preferably 1.2 mm or more, and preferably 3 mm or less, particularly preferably 2.5 mm or less, specifically 1 mm or more and 3 mm or less, preferably 1 The method for producing a non-woven fabric according to any one of <26> or <27>, which is 2 mm or more and 2.5 mm or less.

<29>
The mechanical stretching ratio of the first uneven roll and the second uneven roll is preferably 1.5 times or more, particularly preferably 1.7 times or more, and preferably 3.0 times or less, Particularly preferably, it is 2.8 times or less, specifically, 1.5 times or more and 3.0 times or less, preferably 1.7 times or more and 2.8 times or less, <26> to <28 > The manufacturing method of the nonwoven fabric any one of.
<30>
The nonwoven fabric manufactured by the manufacturing method as described in said <26>-<29>.
<31>
An absorbent article having a top sheet disposed on the skin facing surface side, a back sheet disposed on the non-skin facing surface side, and an absorbent body interposed between the both sheets,
The said surface sheet is an absorptive article currently formed with the nonwoven fabric any one of said <1>-<25> or <30>.

  Hereinafter, the nonwoven fabric of the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by the examples.

[Example 1]
The nonwoven fabric of Example 1 of the form shown in FIG.1 and FIG.2 was manufactured using the manufacturing apparatus 100 shown in FIG. The constituent fibers supplied to the manufacturing apparatus 100 are shown in Table 1 below. As shown in Table 1, the constituent fiber is a fiber made of only high elongation fiber and having no elasticity (elastomer). Further, the high elongation fiber was a concentric core-sheath type composite fiber having a core part made of polyethylene terephthalate and a sheath part made of polyethylene. The elongation of the high elongation fiber was 350%. Moreover, regarding the manufacturing apparatus 100, the distance (pitch) between the large-diameter convex portions 404, 404 included in the pair of concave and convex rolls 401, 402 is 2 mm, and the pushing amount of the pair of concave and convex rolls 401, 402 is 1.2 mm. Yes, and the mechanical draw ratio was 1.9 times.

[Example 2]
Regarding the manufacturing apparatus 100 in Example 1, the amount of pushing of the pair of concave and convex rolls 401 and 402 is changed to 1.6 mm, and the mechanical stretching ratio is changed to 2.3 times, and the same as Example 1 is performed. A nonwoven fabric was produced.

Example 3
Regarding the manufacturing apparatus 100 in Example 1, the amount of pushing of the pair of concave and convex rolls 401 and 402 is changed to 2.0 mm, and the mechanical draw ratio is changed to 2.7 times, and the same as in Example 1 is performed. A nonwoven fabric was produced.

Example 4
Regarding the constituent fibers in Example 1, the nonwoven fabric of Example 4 was produced in the same manner as in Example 1 except that the elongation of the high elongation fiber was changed to 250%.

Example 5
Regarding the constituent fibers in Example 2, the nonwoven fabric of Example 5 was produced in the same manner as in Example 2 except that the elongation of the high elongation fiber was changed to 250%.

Example 6
Regarding the constituent fibers in Example 3, the nonwoven fabric of Example 6 was produced in the same manner as Example 3 except that the elongation of the high elongation fiber was changed to 250%.

[Comparative Example 1]
Regarding the constituent fiber in Example 1, it was changed to an already drawn conjugate fiber. Specifically, the elongation of the composite fiber was 80% drawn fiber. A nonwoven fabric of Comparative Example 1 was produced in the same manner as in Example 1 except that the fiber was changed.

[Comparative Example 2]
The constituent fiber in Example 3 was changed to a composite fiber that had already been drawn. Specifically, the elongation of the composite fiber was 80% drawn fiber. A nonwoven fabric of Comparative Example 2 was produced in the same manner as in Example 3 except that the fiber was changed.

[Comparative Example 3]
By the method according to the manufacturing method described in Patent Document 1, the nonwoven fabric of Comparative Example 3 was formed so as to include the high elongation fiber that is the constituent fiber in Example 4 and the elastic fiber. Note that the pressing amount and the mechanical stretching ratio of the pair of concave and convex rolls 401 and 402 are the same as those in Example 4.

[Comparative Example 4]
By the method according to the manufacturing method described in Patent Document 1, the nonwoven fabric of Comparative Example 4 was formed so as to include the high elongation fiber that is the constituent fiber in Example 6 and the elastic fiber. Note that the pressing amount of the pair of concave and convex rolls 401 and 402 and the mechanical stretching ratio are the same as those in Example 6.

<Evaluation>
Regarding the nonwoven fabrics of Examples 1 to 6 and Comparative Examples 1 to 4, the existence ratio of the changing point 18 from the small diameter part 16 to the large diameter part 17 is evaluated by the following method. 18 positions were measured. Moreover, the fiber diameter of the small diameter part 16 and the large diameter part 17 was measured by the method mentioned above. The results are shown in Table 1 below.
Moreover, with respect to the nonwoven fabrics of Examples 1 to 6 and Comparative Examples 1 to 4, the fiber density in the top region 13a, the bottom region 13b or the side region 13c, and the top region 13a, the bottom region 13b or the side by the method described above. The number of change points 18 in the area 13c was measured. The results are shown in Table 1 below.
Moreover, about the nonwoven fabric of Examples 1-6 and Comparative Examples 1-4, the touch and liquid permeability were evaluated by the following method. The results are shown in Table 1 below.

[Evaluation of the ratio of change points 18]
The 20 constituent fibers of the nonwoven fabric were extracted at random, and each constituent fiber was magnified 110 times using a scanning electron microscope: JCM-5100 (trade name) manufactured by JEOL Ltd. The presence or absence of the changing point 18 from the large diameter portion 17 to the large diameter portion 17 was observed. The existence ratio was calculated as follows.
Abundance ratio (%) = number of fibers having changing point 18/20 fibers × 100
Here, as described above, the change point 18 is a part that continuously changes gradually from a small diameter part to a large diameter part or a part that continuously changes over a plurality of stages, and a core part of a constituent fiber. It means a part where the fiber diameter changes extremely without including the state in which the fiber diameter changes by peeling between the 1 resin component and the second resin component constituting the sheath.

[Evaluation of the position of the change point 18]
When there is a change point 18, the interval T between the adjacent fusion portions 12, 12 is divided into three equal parts, the region AT on one fusion portion 12 side, the region BT on the other fusion portion 12 side, The area is divided into a central area CT. And it observed that the change point 18 was distribute | arranged to any of said area | region AT, said area | region BT, or center area | region CT.
<Evaluation results>
A: Among fibers having change points, there are a plurality of fibers having change points in the region AT or the region BT and also in the center region CT.
B: Among fibers having changing points, there are a plurality of fibers having changing points only in the region AT or the region BT.
C: Among fibers having change points, there are a plurality of fibers having change points only in the central region CT.

[Evaluation of the feel of nonwoven fabric]
Twenty monitors were touched in a state where the nonwoven fabric was not visible, and the touches such as flexibility, softness, and cushioning properties were comprehensively evaluated according to the following five criteria. The results are shown as an average value of 20 people.
<Evaluation criteria>
5: Very good 4: Good 3: Normal 2: Bad 1: Very bad In addition, if the average evaluation result of 20 people is 4 or more, improvement of the touch is recognized by the user and high evaluation is obtained. Is a level that can be expected.

[Evaluation of liquid permeability of nonwoven fabric]
The liquid permeability of the nonwoven fabric was measured according to the “153.0-02 REPEATED Liquid Strike-Through Time” method of EDANA (European Nonwoven Fabric Manufacturers Association) using a strike-through time measuring device Lister manufactured by Lenzing Technik. Liquid Strike-Through Time indicates the time (seconds) required for a predetermined amount of physiological saline to pass from the front surface to the back surface of the nonwoven fabric. Specifically, ten sheets of dedicated filter paper were placed on the pedestal of the testing machine, and a nonwoven fabric was placed thereon. Next, a strike-through plate having electrodes was placed on the nonwoven fabric, and physiological saline (Otsuka Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd. 10 ml of the product name was put in, and then the tester was turned on.From the state in which the physiological saline touched the electrode, the physiological saline passed through the nonwoven fabric, the water level dropped, and the electrode was not in contact with the electrode. The average time was taken as the liquid permeation time of the nonwoven fabric, and the shorter the liquid permeation time, the better the liquid permeability.

  According to the results in Table 1, the non-woven fabrics of Examples 1 to 6 are different from the non-woven fabrics of Comparative Examples 1 to 4 in that the change point 18 from the small diameter portion 16 to the large diameter portion 17 is the region AT or the region. The presence of the small-diameter portion 16 having a low rigidity so as to be adjacent to the fused portion 12 that is present in the BT, in other words, increases the rigidity of the nonwoven fabric, thereby improving the flexibility of the nonwoven fabric and having a good touch. I understood. Furthermore, since the nonwoven fabrics of Examples 1 to 6 have many change points 18 in the side region 13c, the ridges 13 easily follow the movement of the wearer's skin and have a good touch. I understood. Moreover, since the nonwoven fabric of Example 1- Example 6 has many positions of the change point 18 in the side part area | region 13c, and the fiber density of the side part area | region 13c is low, it turned out that liquid permeability is favorable.

  Moreover, according to the result of Table 1, since the nonwoven fabric of Comparative Examples 1-2 uses the stretched fiber with low elongation, the 1st resin component which comprises the core part of a constituent fiber by extending | stretching, and a sheath part Peeling occurs between the constituent second resin components. For this reason, the peeled portion of the sheath is caught on the skin, and the touch is lowered. Since it is difficult to maintain the uneven shape and the core portion is exposed and water-repellent, the liquid passing time is reduced. Next, the nonwoven fabric of Comparative Example 3 has a configuration in which elastic fibers are contained in the nonwoven fabric of Example 4. As described above, when elastic fibers are contained, the nonwoven fabric is stretched while being contracted. Therefore, even when the mechanical draw ratio is the same, it is difficult to form a change point, and the fiber density is not easily lowered. Thereby, the nonwoven fabric of the comparative example 3 is hard to produce the effect of the improvement of touch and liquid permeability. Next, the nonwoven fabric of Comparative Example 4 has a configuration in which elastic fibers are contained in the nonwoven fabric of Example 6. As described above, when elastic fibers are contained, the nonwoven fabric is stretched while being contracted. Therefore, it is difficult to make a change point that is a part where the fiber diameter changes extremely in the present application, and from the small diameter portion 16 to the large diameter portion 17 continuously. A site that gradually changes is likely to be formed. In the nonwoven fabric of Comparative Example 4, the continuously and gradually formed portion formed therein is not observed near the fusion point because it contains elastic fibers and is not easily stretched locally near the fusion point. Thereby, the nonwoven fabric of the comparative example 4 is hard to produce the effect of the improvement of touch and liquid permeability.

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric 11 Constituent fiber 12 Fusion part 13 Convex part 14 Concave part 13a Top area 13b Bottom area 13c Side area 16 Small diameter part 17 Large diameter part 18 Change point 100 Manufacturing apparatus 200 Web formation part 201 Web formation apparatus 300 Hot air treatment Section 301 Hood 302 Conveyor belt 400 Stretched section 401, 402 Uneven roll 403, 404 Large diameter convex section

Claims (8)

A non-woven fabric provided with a plurality of fusion parts formed by heat-sealing the intersections of the constituent fibers,
The constituent fibers include high elongation fibers,
Paying attention to one of the constituent fibers, the constituent fiber has a large diameter portion having a large fiber diameter sandwiched between two small diameter portions having a small fiber diameter between the adjacent fused portions. And
A non-woven fabric in which a changing point from the small-diameter portion adjacent to the fused portion to the large-diameter portion is arranged within a range of 1/3 of the interval between the fused portions adjacent to the fused portion.   The non-woven fabric according to claim 1, wherein the constituent fibers are composed only of inelastic fibers.   The nonwoven fabric according to claim 1, wherein a plurality of the large-diameter portions are arranged between the adjacent fusion portions, paying attention to one of the constituent fibers.   The nonwoven fabric according to any one of claims 1 to 3, wherein the nonwoven fabric is a nonwoven fabric having a concavo-convex structure in which streak-like ridges and ridges extending in one direction are alternately arranged. The non-woven fabric has a top region, a bottom region, and a side region located therebetween,
The top of the ridge is formed from the top region, the bottom of the ridge is formed from the bottom region,
The nonwoven fabric according to claim 4, wherein the fiber density in the side region is smaller than the fiber density in the top region and the fiber density in the bottom region. The non-woven fabric has a top region, a bottom region, and a side region located therebetween,
The top of the ridge is formed from the top region, the bottom of the ridge is formed from the bottom region,
The number of fibers having change points in the constituent fibers constituting the side region, the number of fibers having change points in the constituent fibers constituting the top region, and the change point in the constituent fibers constituting the bottom region The nonwoven fabric according to claim 4 or 5, wherein the number of the nonwoven fabrics is greater than the number of the nonwoven fabrics. A fusing step of forming a fiber sheet by thermally fusing the intersections of the constituent fibers of the fiber web containing high elongation fibers at the fusing portion;
A method for producing a nonwoven fabric comprising a stretching step of stretching the fiber sheet in one direction,
In the stretching step, the fiber sheet is stretched, and the fiber having a large fiber diameter is sandwiched between two small-diameter portions having a small fiber diameter in one constituent fiber between the adjacent fused portions. A method for producing a nonwoven fabric, wherein a diameter portion is formed, and a change point from the small diameter portion to the large diameter portion is formed within a range of 1/3 of an interval between the fusion portions adjacent to the fusion portion. An absorbent article having a top sheet disposed on the skin facing surface side, a back sheet disposed on the non-skin facing surface side, and an absorbent body interposed between the both sheets,
The said surface sheet is an absorbent article formed with the nonwoven fabric of any one of Claims 1-6.

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