CN106794082B - Absorbent article - Google Patents

Abstract

The absorbent article of the present invention has a liquid-permeable front sheet (2) forming a skin contact surface, a back sheet (3), and an absorbent body (4) interposed between the two sheets, and has a longitudinal direction (X) and a width direction (Y), wherein the front sheet (2) includes a nonwoven fabric (1) having a concavo-convex structure in which stripe-shaped ridges (13) and grooves (14) extending in the longitudinal direction are alternately arranged in the width direction (Y), the grooves (13) are joined to adjacent lower side sheets (6), and the ridges (13) have a hollow structure between the ridges and the lower side sheets (6). The nonwoven fabric (1) comprises fibers having a large diameter section (17) and a small diameter section (15) having different fiber diameters, and the absorbent body (4) has high flexibility regions (5) having lower flexural rigidity than other portions at a plurality of locations in the width direction.

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article.

Background

As a topsheet of an absorbent article such as a sanitary napkin for menstrual period, various structures having an uneven structure on a skin contact surface have been proposed. For example, the present applicant has proposed a front surface sheet in which an uneven portion forming sheet having a plurality of parallel pleats is linearly joined to a base sheet between the pleats (patent document 1).

Further, the present applicant proposed a technique concerning a nonwoven fabric manufactured in such a manner that: a method for producing a nonwoven fabric having a low-elongation inelastic fiber includes arranging a web containing inelastic fibers on one surface of a web containing elastic fibers, subjecting the web to a hot air treatment of an air-through method to thermally weld intersections between the fibers, integrating the web, extending a fiber sheet formed in this manner to elongate the inelastic fibers having a low-elongation, and then releasing the extension of the fiber sheet (patent document 2). In the method for producing a nonwoven fabric described in patent document 2, a stretching device having a pair of concavo-convex rollers capable of meshing with each other is used for stretching a fiber sheet.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2002-165830

Patent document 2: japanese patent laid-open No. 2008-7924

Disclosure of Invention

The present invention provides an absorbent article having a liquid-permeable front sheet forming a skin contact surface, a back sheet, and an absorbent body interposed between the two sheets, and having a longitudinal direction and a width direction, wherein the front sheet comprises a nonwoven fabric having a concavo-convex structure in which stripe-shaped ridges and grooves extending in the longitudinal direction are alternately arranged in the width direction, the ridges are joined to an adjacent lower sheet at the ridges, the ridges have a hollow structure between the ridges and the lower sheet, the nonwoven fabric comprises fibers having large-diameter portions and small-diameter portions having different fiber diameters, and the absorbent body has high-flexibility regions having lower flexural rigidity than other portions at a plurality of locations in the width direction.

Drawings

Fig. 1 is a perspective view showing an incontinence pad as an embodiment of the present invention.

Fig. 2(a) is an enlarged sectional view taken along line II-II in fig. 1, and fig. 2(b) is a view showing the back surface (surface on the non-skin contact surface side) of the absorbent body of the incontinence pad shown in fig. 1.

Fig. 3 is a perspective view showing a nonwoven fabric used for the front sheet of the incontinence pad shown in fig. 1.

Fig. 4 is a schematic view showing a cross section in the thickness direction of the nonwoven fabric shown in fig. 3.

Fig. 5 is a view illustrating a state in which constituent fibers constituting the nonwoven fabric shown in fig. 3 are fixed to each other at a heat-fusion bonded portion.

Fig. 6 is a partially extracted enlarged plan view of the skin contact surface of the incontinence pad showing an example of the arrangement of the concave portions of the front sheet and the joining portions of the lower side sheet.

Fig. 7 is a diagram illustrating the operation and effect of the present invention.

Fig. 8 is a cross-sectional view showing an incontinence pad as another embodiment of the invention (corresponding to fig. 2 (a)).

FIG. 9 is a schematic view showing a manufacturing apparatus which is preferably used for manufacturing the nonwoven fabric shown in FIG. 3.

Fig. 10 is a cross-sectional view D-D of fig. 9.

Fig. 11(a) to 11(c) are explanatory views illustrating a state where a plurality of small diameter portions and large diameter portions are formed in one constituent fiber between adjacent fusion-spliced portions.

Fig. 12(a) to 12(c) are partially enlarged plan views of absorbent bodies showing another example of the arrangement of compressed parts forming highly flexible regions.

Fig. 13 is a sectional view showing another absorber that can be used in the present invention.

Detailed Description

According to the topsheet of patent document 1, effects such as excellent skin touch and an effect of preventing stuffiness can be achieved. The nonwoven fabric produced by the production method described in patent document 2 is formed so as to include elastic fibers and inelastic fibers having different thicknesses in the longitudinal direction. Thus, the thickness of the inelastic fiber varies to improve the skin feel.

However, there is a demand for absorbent articles that further improve the quality such as the texture of the skin.

The present invention addresses the problem of providing an absorbent article that can eliminate the disadvantages of the prior art described above.

Hereinafter, the present invention will be described in accordance with preferred embodiments thereof with reference to the accompanying drawings.

Fig. 1 shows a perspective view of an incontinence pad 10 (hereinafter simply referred to as "incontinence pad 10") as an embodiment of the invention. Fig. 2(a) is an enlarged sectional view II-II of fig. 1, and fig. 2(b) is a view showing the back surface (surface on the non-skin contact surface side) of the absorbent body of the incontinence pad 10 shown in fig. 1.

As shown in fig. 1 and 2(a), the incontinence pad 10 has a liquid-permeable front sheet 2 forming a skin-contacting surface, a liquid-impermeable back sheet 3, and an absorbent body 4 interposed between the two sheets 2, 3. Liquid impermeability includes liquid impermeability. Incontinence pad 10 has a longitudinal shape with a longitudinal direction X and a width direction Y. The longitudinal direction X coincides with the front-rear direction of the wearer when the incontinence pad 10 is worn, and the width direction Y is a direction orthogonal to the longitudinal direction X in a plan view of the incontinence pad 10. Incontinence pad 10 has an oblong shape in plan view.

The front sheet 2 and the back sheet 3 extend from the periphery of the absorbent member 4. An adhesive portion (not shown) for fixing to underwear such as shorts is provided on the surface (non-skin contact surface) of the incontinence pad 10 on the back sheet 3 side. The skin contact surface is a surface of the absorbent article or a component thereof that faces the skin side of the wearer when worn, and the non-skin contact surface is a surface of the absorbent article or a component thereof that faces the side opposite to the skin side of the wearer when worn (usually, the underwear side).

The absorbent body 4 of the incontinence pad 10 comprises an absorbent core 40 and a core sheet 41 enclosing the absorbent core 40. The absorbent core 40 may be formed of a fiber laminate of liquid-absorbent fibers such as pulp, or a mixed fiber laminate of the liquid-absorbent fibers and a water-absorbent polymer. Examples of the liquid-absorbent fibers constituting the absorbent core 40 include cellulose-based hydrophilic fibers such as pulp fibers, rayon fibers, cotton fibers, and cellulose acetate fibers. In addition to cellulose-based hydrophilic fibers, polyolefin-based fibers such as polyethylene and polypropylene, and polycondensation-based fibers such as polyester and polyamide can be included. Examples of the water-absorbent polymer include sodium polyacrylate, an acrylic acid-vinyl alcohol copolymer, a crosslinked sodium polyacrylate, a starch-acrylic acid graft copolymer, an isobutylene-maleic anhydride copolymer, a saponified product thereof, and polyaspartic acid. The fibers and the water-absorbent polymer can be used in combination of one or more kinds, respectively.

As the core-spun sheet 41, a water-permeable fiber sheet such as tissue paper or nonwoven fabric is preferably used. The core sheet 41 may be formed by wrapping the entire absorbent core 40 with one sheet, may be formed by wrapping the entire absorbent core 40 with 2 or more core sheets, and may be formed by wrapping the skin contact surface side and the non-skin contact surface side of the absorbent core 40 with different sheets, for example.

The thickness of the absorbent body 4 is preferably 1mm or more, more preferably 2mm or more, and further preferably 15mm or less, more preferably 10mm or less, and further preferably 1mm or more and 15mm or less, and further preferably 2mm or more and 10mm or less.

The thickness of the absorbent body 4 was measured by the following method.

In the measurement of the thickness T, a peacock precision measuring instrument (model R1-C) as a micrometer having 2 parallel pressing surfaces (a fixed pressing surface and a movable pressing surface) was used, and the measurement was performed under conditions in which the diameter of the movable pressing surface of the measuring probe was 5mm and the pressure was 100kPa or less, and the size of the test piece for measurement was set to the size of the plate described below or more. A20 mm X20 mm plate (weight: 5.4g) was placed on the test piece, and the movable pressure surface of the measuring element was brought into contact with the plate at a speed of 2mm/s, and the value immediately after stabilization was read. The pressure between the pressing surfaces (the pressure applied to the test piece) is 1.3kPa or less.

As a material for forming the back sheet 3, various materials conventionally used for back sheets of absorbent articles can be used without particular limitation, and for example, a liquid-impermeable or water-repellent resin film, a laminate of a resin film and a nonwoven fabric, or the like can be used.

Leakage preventing cuffs 8 extending in the longitudinal direction are provided on both sides in the width direction Y of the skin contact surface side of the incontinence pad 10. The leakage preventing cuffs 8 include free ends 8a and fixing regions 8b extending in the lengthwise direction, respectively. The fixing region 8b is located on the front sheet 2. The leakage preventing cuffs 8 are fixed to the front sheet 2 at fixing regions 8 b. The fixing region 8b of the leakage preventing cuff 8 extends outward in the width direction Y, and its extending portion is joined to the extending portion in the width direction of the back sheet 3 to form the flap 7. In the leakage preventive cuff 8, an elastic member 8c extending in the longitudinal direction X is attached in an extended state to a position at or near the free end 8 a. A plurality of elastic members 8c are arranged substantially parallel to each other. The portions to which the plurality of elastic members 8c are attached form a planar elastic region 8 d. The planar elastic region 8d has a specific length in the width direction Y and extends in the longitudinal direction X at least at a position corresponding to a wearer's excretory part. The planar elastic region 8d can expand and contract along the longitudinal direction X. By contraction of the elastic member 8c, the position between the free end 8a and the fixed region 8b of the leakage prevention cuff 8 rises in a substantially L-shape toward the body of the wearer, and the planar elastic region 8d abuts against the skin of the wearer to prevent liquid leakage.

As shown in fig. 3, the front sheet 2 of the incontinence pad 10 of the present embodiment includes a nonwoven fabric 1 having an uneven structure in which stripe-shaped ridges 13 and grooves 14 extending in the longitudinal direction X are alternately arranged in the width direction. As shown in fig. 2, the front sheet 2 is joined to the adjacent lower sheet 6 at the concave portion 14 thereof, and the convex portion 13 has a hollow structure between itself and the lower sheet 6. As shown in fig. 5, the nonwoven fabric 1 constituting the front sheet 2 includes fibers 11 having large diameter portions 17 and small diameter portions 16 and 16 having different fiber diameters.

The nonwoven fabric 1 constituting the front sheet 2 will be described in more detail.

Fig. 3 is a perspective view of a nonwoven fabric 1 (hereinafter referred to as "nonwoven fabric 1") used as a top sheet 2 in an incontinence pad 10 of the present embodiment. Fig. 4 is a schematic view showing a cross section in the thickness direction of the nonwoven fabric 1 shown in fig. 3. Fig. 5 is an enlarged schematic view of the constituent fibers 11 of the nonwoven fabric 1 shown in fig. 3. As shown in fig. 3, the nonwoven fabric 1 is a nonwoven fabric having a plurality of fusion portions 12 (see fig. 5) formed by thermally fusing intersections of the constituent fibers 11. In the nonwoven fabric 1 constituting the topsheet 2, the "one direction" in which the ridges 13 and the valleys 14 extend is the same direction as the longitudinal direction X of the incontinence pad 10, and the "one direction" in which the ridges 13 and the valleys 14 extend in the nonwoven fabric 1 is also referred to as the X direction.

More specifically, as shown in fig. 4, the nonwoven fabric 1 includes a plurality of convex portions 13 each having a cross-sectional shape of both the front and back surfaces a, b formed in a convex shape upward in the thickness direction (Z direction), and concave portions 14 located between the adjacent convex portions 13, 13. Both the front and back surfaces a, b of the concave portion 14 have a concave shape in cross section toward the upper side in the thickness direction (Z direction) of the nonwoven fabric. In other words, both the front and back surfaces a and b of the concave portions 14 have a convex cross-sectional shape extending downward in the thickness direction (Z direction) of the nonwoven fabric. The plurality of ridges 13 each extend continuously in one direction (X direction) of the nonwoven fabric 1, and the plurality of grooves 14 are also formed in a groove shape extending continuously in the one direction X of the nonwoven fabric 1. The ridges 13 and the valleys 14 are alternately arranged in parallel with each other in a direction (Y direction) orthogonal to the one direction (X direction).

As described below, the nonwoven fabric 1 is produced by embossing the fiber sheet 1a using a pair of embossing rollers 401 and 402 that mesh with each other. The one direction (X direction) of the nonwoven fabric 1 is the same direction as the machine direction (MD, traveling direction) when the nonwoven fabric 1 is manufactured by embossing the fiber sheet 1a, and the direction (Y direction) orthogonal to the one direction (X direction) of the nonwoven fabric 1 is the same direction as the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, traveling direction).

The constituent fibers 11 of the nonwoven fabric 1 include high-elongation fibers. Here, the high-elongation fibers included in the constituent fibers 11 mean not only fibers having high elongation at the stage of the raw material fibers but also fibers having high elongation at the stage of the produced nonwoven fabric 1. Examples of the "high-elongation fiber" include, in addition to elastic fibers (elastic bodies) which stretch and contract, heat-extensible fibers which are obtained by melt-spinning at a low speed to obtain composite fibers and then subjecting the composite fibers to a heat treatment and/or a crimping treatment without stretching treatment as described in paragraph [0033] of Japanese patent laid-open No. 2010-168715 and which are elongated by heating to change the crystalline state of the resin, fibers produced under conditions where the relative spinning speed is low using a resin such as polypropylene or polyethylene, fibers produced by spinning a polyethylene-polypropylene copolymer having a low crystallinity, or a polyethylene dry-blended with polypropylene. Among these fibers, the high-elongation fiber is also preferably a core-sheath composite fiber having heat fusion properties. The core-sheath composite fiber may be concentric core-sheath type, or eccentric core-sheath type, or side-by-side type, or hetero-type, but concentric core-sheath type is particularly preferable. The fineness of the high-elongation fiber is preferably 1.0dtex or more and 10.0dtex or less, and more preferably 2.0dtex or more and 8.0dtex or less at the stage of the raw material, from the viewpoint that a nonwoven fabric or the like which is soft and excellent in touch feeling or the like can be produced in any form of the fiber.

The constituent fibers 11 of the nonwoven fabric 1 may be formed of other fibers in addition to the high-elongation fibers, but are preferably formed of only the high-elongation fibers. Examples of the other fibers include a non-heat-extensible core-sheath heat-fusible composite fiber obtained by stretching a fiber containing 2 kinds of components having different melting points, and a fiber not originally having heat-fusible properties (for example, a natural fiber such as cotton or pulp, rayon, acetate fiber, or the like). When the nonwoven fabric 1 is configured to include other fibers in addition to the high-elongation fibers, the ratio of the high-elongation fibers in the nonwoven fabric 1 is preferably 50 mass% or more and 100 mass% or less, and more preferably 80 mass% or more and 100 mass% or less.

The thermally extensible fiber as the high-extensibility fiber is a composite fiber which is subjected to non-extension treatment or weak extension treatment at the stage of raw material, and for example, has a first resin component constituting the core portion and a second resin component including polyethylene resin constituting the sheath portion, and the first resin component has a higher melting point than the second resin component. The first resin component is a component exhibiting thermal extensibility of the fiber, and the second resin component is a component exhibiting thermal fusion bonding. The finely cut fiber sample (sample weight: 2mg) was thermally analyzed at a temperature increase rate of 10 ℃/min using a differential scanning calorimeter (DSC 6200 manufactured by Seiko electronics Co., Ltd.), the melting peak temperatures of the respective resins were measured, and the melting points of the first resin component and the second resin component were defined by the melting peak temperatures. When the melting point of the second resin component cannot be clearly measured by this method, this resin is defined as a "resin having no melting point". At this time, as the temperature at which molecules of the second resin component start to flow, a temperature at which the second resin component is welded to a degree at which the strength of the weld point of the fiber can be measured is used as the softening point, and this softening point is used instead of the melting point.

As the second resin component constituting the sheath portion, polyethylene resin is included as described above. Examples of the polyethylene resin include Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), and Linear Low Density Polyethylene (LLDPE). A density of 0.935g/cm is particularly preferred³Above and 0.965g/cm³The following high density polyethylene. The second resin component constituting the sheath portion is preferably a polyethylene resin monomer, and other resins may be mixed. Examples of the other resins to be mixed include polypropylene resins, ethylene-vinyl acetate copolymers (EVA), ethylene-vinyl alcohol copolymers (EVOH), and the like. However, the second resin component constituting the sheath portion is preferably a polyethylene resin in an amount of 50% by mass or more, particularly preferably 70% by mass or more and 100% by mass or less, of the resin components of the sheath portion. The polyethylene resin preferably has a crystallite size of 10nm to 20nm, more preferably 11.5nm to 18 nm.

As the first resin component constituting the core portion, a resin component having a higher melting point than the polyethylene resin as the resin constituting the sheath portion can be used without particular limitation. Examples of the resin component constituting the core include polyolefin resins (other than polyethylene resins) such as polypropylene (PP), polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), and the like. Further, a polyamide-based polymer, a copolymer having 2 or more resin components, or the like can also be used. In this case, the melting point of the core portion is set to the melting point of the resin having the highest melting point. From the viewpoint of ease of production of the nonwoven fabric, the difference between the melting point of the first resin component constituting the core portion and the melting point of the second resin component constituting the sheath portion (the former-the latter) is preferably 20 ℃ or more, and further preferably 150 ℃ or less.

The preferred orientation index of the first resin component in the thermally extensible fibers as the high-elongation fibers naturally varies depending on the resin used, and when the first resin component is a polypropylene resin, for example, the orientation index is preferably 60% or less, more preferably 40% or less, and still more preferably 25% or less. When the first resin component is a 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 orientation index of the second resin component is preferably 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 chains of the resin constituting the fiber.

The orientation indexes of the first resin component and the second resin component are determined by the methods described in paragraphs [0027] to [0029] of Japanese patent application laid-open No. 2010-168715. Further, methods for achieving the above orientation index of each resin component in the thermally extensible conjugate fiber are described in paragraphs [0033] to [0036] of Japanese patent laid-open No. 2010-168715.

The elongation of the high-elongation fiber is preferably 100% to 800%, more preferably 200% to 500%, and still more preferably 250% to 400% at the stage of the raw material. By using the high-elongation fiber having an elongation in this range, the fiber is smoothly elongated in the elongation device, and the change point from the small diameter portion to the large diameter portion described above is adjacent to the welded portion, so that the skin feel is good.

The elongation of the high-elongation fiber is measured in accordance with JIS L-1015 under the conditions of measuring the ambient temperature and humidity of 20 + -2 ℃, 65 + -2% RH, the clamping interval of a tensile testing machine of 20mm, and the drawing speed of 20 mm/min. When fibers are collected from a nonwoven fabric produced and the elongation is measured, the measurement cannot be performed with the nip interval set to 10mm or 5mm when the nip interval is set to 20mm, that is, when the measured length of the fibers is less than 20 mm.

The ratio (mass ratio, former: latter) of the first resin component to the second resin component in the high-elongation fiber is preferably 10: 90-90: 10, more preferably 20: 80-80: 20, particularly preferably 50: 50-70: 30. the fiber length of the high-elongation fiber is suitably used in accordance with the method for producing the nonwoven fabric. For example, when a nonwoven fabric is produced by a carding 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 in the stage of the raw material according to the specific use of the nonwoven fabric. When a nonwoven fabric is used as a component of an absorbent article such as a topsheet of an absorbent article, a structure of 10 μm or more and 35 μm or less is preferably used, and a structure of 15 μm or more and 30 μm or less is particularly preferably used. The fiber diameter was measured by the following method.

[ measurement of fiber diameter of fiber ]

The fiber diameter (μm) of the fiber was measured by observing the cross section of the fiber at 200 to 800 times magnification using a scanning electron microscope (JCM-5100, manufactured by japan electronics). The cross section of the fiber was obtained by cutting the fiber with a Feather razor (product No. FAS-10, manufactured by Feather safety razor (strand)). The fiber diameter of the drawn 1 fiber was measured at 5 positions in the case of an approximate circle, and the average of the values at 5 positions obtained by the measurement was defined as the fiber diameter.

As the heat-extensible fibers which are high-extensible fibers at the stage of the raw material, fibers described in Japanese patent No. 4131852, Japanese patent application laid-open No. 2005-350836, Japanese patent application laid-open No. 2007-303035, Japanese patent application laid-open No. 2007-204899, Japanese patent application laid-open No. 2007-204901, and Japanese patent application laid-open No. 2007-204902 can be used in addition to the above-mentioned heat-extensible fibers.

As shown in fig. 5, 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 has a large diameter portion 17 having a large fiber diameter sandwiched between 2 small diameter portions 16, 16 having a small fiber diameter between adjacent fusion-bonded portions 12, 12. Specifically, as shown in fig. 5, focusing on one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, a small diameter portion 16 having a small fiber diameter is formed to extend with substantially the same fiber diameter from a fusion portion 12 formed by thermally fusing an intersection with the other constituent fiber 11. Focusing on this one constituent fiber 11, between the small diameter portions 16, 16 extending from the adjacent fusion-spliced portions 12, respectively, a large diameter portion 17 having a larger fiber diameter than the small diameter portion 16 is formed to extend with substantially the same fiber diameter. More specifically, the nonwoven fabric 1 has the constituent fibers 11 formed as follows: when focusing on one constituent fiber 11, a small diameter portion 16 on the side of one welded portion 12, 1 large diameter portion 17, and a small diameter portion 16 on the side of the other welded portion 12 are arranged in this order from one welded portion 12 to the other welded portion 12 in the adjacent welded portions 12, 12.

As described above, the small diameter portion 16 having low rigidity is present adjacent to the welded portion 12 having high rigidity of the nonwoven fabric 1, so that the nonwoven fabric 1 has improved flexibility and a good texture. In addition, the nonwoven fabric 1 has a plurality of large diameter portions 17, that is, the smaller diameter portions 16 having a lower rigidity are present as the constituent fibers 11 are more increased in flexibility, and the texture is more favorable.

As shown in fig. 5, when focusing attention on one constituent fiber 11 of the constituent fibers 11 of the nonwoven fabric 1, the nonwoven fabric 1 has a plurality of (2 in the nonwoven fabric 1) large diameter portions 17 of the constituent fibers 11 between adjacent fusion-bonded portions 12 and 12. To describe in detail, the nonwoven fabric 1 includes the constituent fibers 11 formed in the following manner: when focusing on one constituent fiber 11, a small diameter portion 16 on the side of one welded portion 12, a first large diameter portion 17, a small diameter portion 16, a second large diameter portion 17, and a small diameter portion 16 on the side of the other welded portion 12 are arranged in this order from one welded portion 12 to the other welded portion 12 of the adjacent welded portions 12, 12. In the nonwoven fabric 1, when focusing on one constituent fiber 11, it is preferable that 1 or more and 5 or less large diameter portions 17 are provided between adjacent welded portions 12, and it is more preferable that 1 or more and 3 or less large diameter portions 17 are provided, from the viewpoint of improvement in the texture and reduction in the strength of the nonwoven fabric.

The fiber diameter (diameter L) of the small diameter portion 16₁₆) Fiber diameter (diameter L) relative to the large diameter portion 17₁₇) Ratio (L) of₁₆/L₁₇) Preferably 0.5 to 0.8, and more preferably 0.55 to 0.7. Specifically, the fiber diameter (diameter L) of the small diameter portion 16 is such that the tactile sensation of the skin is improved₁₆) Preferably 5 to 28 μm, and more preferably 6.5 μmAnd 20 μm or less, and particularly preferably 7.5 μm or more and 16 μm or less. From the viewpoint of improving the tactile sensation to the skin, the fiber diameter (diameter L) of the large diameter portion 17₁₇) Preferably 10 to 35 μm, more preferably 13 to 25 μm, and particularly preferably 15 to 20 μm.

Fiber diameters (diameter L) of the small diameter portion 16 and the large diameter portion 17₁₆、L₁₇) The measurement was carried out in the same manner as the measurement of the fiber diameter of the fiber described above.

As shown in fig. 5, when one of the constituent fibers 11 of the nonwoven fabric 1 is focused on, the point of change 18 from the small diameter portion 16 adjacent to the welded portion 12 to the large diameter portion 17 is disposed within 1/3 of the interval T between the adjacent welded portions 12, 12 from the welded portion 12. Here, the change point 18 of the nonwoven fabric of the present invention does not include a portion where the fiber diameter changes gradually and 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 or a portion where the fiber diameter changes continuously in a plurality of stages, but means a portion where the fiber diameter changes extremely in one stage. When the one constituent fiber 11 is a thermally extensible conjugate fiber, the change point 18 of the nonwoven fabric of the present invention does not include a state in which the fiber diameter changes due to peeling between the first resin component constituting the core portion and the second resin component constituting the sheath portion, but always means a portion in which the fiber diameter changes due to stretching.

The arrangement of the change points 18 within the range of 1/3 of the interval T between the adjacent welded parts 12, 12 from the welded part 12 means that the constituent fibers 11 of the nonwoven fabric 1 are randomly extracted, and as shown in fig. 5, the constituent fibers 11 are enlarged to a size (100 to 300 times) that allows observation between the adjacent welded parts 12, 12 of the constituent fibers 11 using JCM-5100 (trade name) manufactured by japan electronics corporation as a scanning electron microscope. Next, the interval T between the centers of the adjacent welded parts 12, 12 is divided into three equal parts, i.e., a region AT on the side of one welded part 12, a region BT on the side of the other welded part 12, and a central region CT. The change point 18 is disposed in the area AT or the area BT. The nonwoven fabric 1 in which the change points 18 are arranged within 1/3 of the interval T between the adjacent welded parts 12, 12 from the welded part 12 means a nonwoven fabric in which 20 constituent fibers 11 of the nonwoven fabric 1 are randomly extracted, and the constituent fibers 11 in which the change points 18 are arranged in the region AT or the region BT have AT least 1 or more out of 20 constituent fibers 11. Specifically, from the viewpoint of improving the tactile sensation to the skin, the number of the cells is preferably 1 or more, more preferably 5 or more, and particularly preferably 10 or more.

The nonwoven fabric 1 includes a top region 13a, a bottom region 13b, and a side region 13c therebetween when the nonwoven fabric 1 is viewed in cross section along the thickness direction Z as shown in fig. 4. The top region 13a, the bottom region 13b, and the side regions 13c extend continuously in one direction (X direction) of the nonwoven fabric 1. When the nonwoven fabric 1 is viewed in cross section along the thickness direction Z, the top region 13a, the bottom region 13b, and the side regions 13c are distinguished by bisecting the thickness of the nonwoven fabric 1 in the Z direction, defining the upper portion in the thickness direction Z as the top region 13a, the central portion as the side region 13c, and the lower portion as the bottom region 13 b. In the nonwoven fabric 1, the top portions of the raised strips 13 are formed by the top regions 13a, and the bottom portions of the recessed strips 14 are formed by the bottom regions 13 b.

As shown in fig. 4, when the nonwoven fabric 1 is viewed in the thickness direction Z, the fiber density of the side regions 13c is lower than the fiber density of the top region 13a and the fiber density of the bottom region 13 b. The fiber density is the number of fibers per unit area in the cross section of the nonwoven fabric 1. Therefore, the side regions 13c are sparse regions having a smaller number of fibers (a larger distance between fibers) than the top regions 13a and the bottom regions 13b, and the air permeability of the nonwoven fabric 1 as a whole is improved and the liquid permeability is also improved. Further, since the fiber density of the side region 13c is minimized, the projected strips 13 can easily follow the movement of the wearer's body, and a good skin feel can be achieved. In order to impart the fiber density to the side regions 13c as described above, the nonwoven fabric 1 may be produced by a production method described later.

Fiber density (D) of the side region 13c_13c) Fiber density (D) relative to the top region 13a_13a) Or the fiber density of the bottom region 13b(D_13b) Ratio (D)_13c/D_13a，D_13c/D_13b) Preferably 0.15 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less. Specifically, regarding a specific value of the fiber density of the nonwoven fabric 1, the fiber density (D) of the top region 13a_13a) Preferably 90 roots/mm²Above and 200 pieces/mm²The number of the cells is preferably 100/mm or less²Above 180 pieces/mm²The following. Furthermore, the fiber density (D) of the bottom region 13b_13b) Preferably 80 roots/mm²Above and 200 pieces/mm²Less than 90 pieces/mm is more preferable²Above 180 pieces/mm²The following. Further, the fiber density (D) of the side region 13c_13c) Preferably 30 roots/mm²Above 80 roots/mm²The number of the cells is preferably 40/mm or less²Above 70 roots/mm₂The following. The fiber density was measured as follows.

[ method for measuring fiber Density in the Top region 13a, bottom region 13b, and side region 13c ]

The nonwoven fabric was cut in the thickness direction Z using a Feather razor (product number FAS-10, manufactured by a Feather safety razor (strand)). The fiber density of the top region 13a was observed by magnifying (adjusting to a magnification of about 150 to 500 times that of about 30 to 60 fibers in cross section) the top region 13a, which is an upper part of the thickness of the cut surface of the nonwoven fabric when trisected in the Z direction, using a scanning electron microscope, and counting a certain unit area (0.5 mm)²Left and right) of the number of cross sections of the fiber cut by the cut surface. Then, the conversion is made to 1mm per unit²The number of cross sections of the fibers in (2) is set as the fiber density of the top region 13 a. The fiber density of the sample was determined at 3 sites and averaged. Similarly, the fiber density of the bottom region 13b is determined by measuring a portion below the cut surface of the nonwoven fabric, which is trisected in the Z direction. Similarly, the fiber density of the side regions 13c is determined by measuring the central portion of the nonwoven fabric in which the thickness of the cut surface is trisected in the Z direction. In addition, as the scanning electron microscope, manufactured by japan electronics (stock) corporation was usedJCM-5100 (trade name).

In addition, the nonwoven fabric 1 of the present embodiment is formed such that the number of fibers having the change points in the constituent fibers constituting the side regions 13c is larger than the number of fibers having the change points 18 in the constituent fibers constituting the top regions 13a and the number of fibers having the change points 18 in the constituent fibers constituting the bottom regions 13 b. The number of fibers having a change point (N) among the fibers constituting the side region 13c_13c) The number of fibers having the change points 18 (N) among the constituent fibers constituting the top region 13a_13a) Or the number of fibers having the change points 18 among the constituent fibers constituting the bottom region 13b (N)_13b) Ratio (N)_13c/N_13a，N_13c/N_13b) Preferably 2 to 20, and more preferably 5 to 20. Specifically, regarding the specific value of the number of fibers having the change points 18 in the nonwoven fabric 1, the number of fibers having the change points 18 (N) among the fibers constituting the top region 13a_13a) Preferably 1 to 15, and more preferably 5 to 15. Further, the number of fibers having the change points 18 (N) among the constituent fibers constituting the bottom region 13b_13b) Preferably 1 to 15, and more preferably 5 to 15. Further, the number of fibers having the change points 18 (N) among the constituent fibers constituting the side regions 13c_13c) Preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less. The number of fibers having the change points 18 is measured as follows.

[ method for measuring the number of fibers having the change points 18 among the fibers constituting the top region 13a, the bottom region 13b, or the side regions 13c ]

The number of fibers having the change points 18 among the constituent fibers 11 constituting the top region 13a is observed by magnifying (adjusting to a magnification capable of measuring about 30 to 60 fiber cross sections, 50 to 500 times) the vicinity of the apex of the top region 13a, which is an upper portion when the thickness of the nonwoven fabric is trisected in the Z direction, using a scanning electron microscope, and 20 of the constituent fibers 11 constituting the top region 13a are randomly extracted, and the number of fibers having the change points 18 among 20 of the constituent fibers 11 is counted. This is the number of fibers having the change points 18 among the constituent fibers constituting the top region 13 a. The number of fibers having the change points 18 among the fibers constituting the top region 13a of the sample was measured at 3 sites and averaged. Similarly, the number of fibers having the change points 18 among the constituent fibers 11 constituting the bottom region 13b is determined by measuring the bottom region 13b in the vicinity of the bottom point, which is a lower portion when the thickness of the nonwoven fabric is trisected in the Z direction. Similarly, the number of fibers having the change points 18 among the constituent fibers 11 constituting the side regions 13c is determined by measuring the central portion of the nonwoven fabric when the thickness thereof is trisected in the Z direction. In addition, as the scanning electron microscope, JCM-5100 (trade name) manufactured by japan electronics (stock) corporation was used.

Regarding the thickness of the nonwoven fabric 1, the overall thickness of the nonwoven fabric 1 in side view is defined as a sheet thickness T_SThe thickness of a part of the non-woven fabric 1 bent in a concavo-convex manner is set as a layer thickness T_L. Sheet thickness T_SPreferably 0.5mm or more and 7mm or less, and more preferably 1.0mm or more and 5mm or less. By setting the range, the body fluid absorption rate at the time of use is high, liquid return from the absorbent body can be suppressed, and appropriate cushioning properties can be achieved.

Layer thickness T_LThe layer thickness T of the top region 13a may be different at different positions in the nonwoven fabric 1_L1Preferably 0.1mm or more and 3.0mm or less, and more preferably 0.2mm or more and 2.0mm or less. Layer thickness T of the base region 13b_L2Preferably 0.1mm or more and 3.0mm or less, and more preferably 0.2mm or more and 2.0mm or less. Layer thickness T of the side region 13c_L3Preferably 0.1mm or more and 3.0mm or less, and more preferably 0.2mm or more and 2.0mm or less. Thickness T of each layer_L1、T_L2、T_L3By setting the relationship (a) to (b) in this range, the body fluid absorption rate in use is high, liquid return from the absorbent body can be suppressed, and appropriate cushioning properties can be achieved.

Sheet thickness T_SSum layer thickness T_LThe measurement was carried out by the following method.

Sheet thickness T_SThe measurement method (2) was carried out by using a thickness measuring instrument while applying a load of 0.05kPa to the nonwoven fabric 1. The thickness measuring device used was a laser displacement meter manufactured by OMRON corporation. Thickness measurements were made at 10 and their average was calculated as the thickness.

Layer thickness T_LThe thickness of each layer was measured by enlarging the cross section of the sheet approximately 20 times using a digital microscope VHX-900 manufactured by KEYENCE.

The pitch between the tops of the ridges 13 adjacent in the Y direction is preferably 1mm to 15mm, and more preferably 1.5mm to 10mm, in a plan view of the nonwoven fabric 1. The height H of the raised ridge portions 13 (see fig. 2 (a)) is preferably 0.5mm to 5mm, and more preferably 1mm to 3 mm. The height H was measured under a no-load condition by observing a cross section of the nonwoven fabric 1 in the thickness direction Z with a microscope.

Further, the grammage of the nonwoven fabric 1 is preferably 15g/m when calculated as an average value of the entire sheet²Above and 50g/m²Hereinafter, more preferably 20g/m²Above and 40g/m²The following.

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

As a method for adhering the fiber treatment agent to the surface of the constituent fiber 11, various known methods can be employed without particular limitation. Examples of the coating include coating by spray coating, coating by a slot coater, coating by roll transfer, and dipping in a fiber treatment agent. These treatments can be performed on the fibers before they are formed into a web, or they can be performed after the fibers are formed into a web by various methods. However, the treatment must be performed before the hot air blowing treatment described later. The fibers having the fiber treatment agent adhered to the surface thereof are dried by, for example, a hot air blowing type dryer at a temperature far lower than the melting point of the polyethylene resin (for example, 120 ℃ or lower).

As shown in fig. 2(a), in the topsheet 2 of the incontinence pad 10 of the present embodiment, the concave portions 14 of the nonwoven fabric 1 constituting the topsheet 2 and the adjacent lower sheet 6 are joined by thermal fusion. The nonwoven fabric 1 includes fibers having a large diameter portion and a small diameter portion having different fiber diameters from each other, and is joined to the adjacent lower sheet 6, thereby having excellent deformation following the movement of the wearer. The lower sheet 6 in the present embodiment is a second sheet 6 including a nonwoven fabric disposed between the topsheet 2 and the absorbent body 4.

The concave portions 14 of the top sheet 2 are continuously joined to the second sheet 6 in the longitudinal direction of the incontinence pad 10, and the joined portions 14s may be formed continuously in the longitudinal direction X of the incontinence pad 10 or may be formed at intervals in the longitudinal direction X as shown in fig. 6, but the joined portions 14s are preferably formed at intervals in the longitudinal direction X from the viewpoint of the following ability to the skin and the feeling of the skin. In the example shown in fig. 6, the joint portions 14s are formed at equal intervals in the longitudinal direction X.

Instead of bonding the top sheet 2 to the lower sheet 6 such as the second sheet by thermal welding, the top sheet may be bonded to the second sheet 6 (lower sheet) by another bonding method such as bonding with an adhesive such as a hot-melt adhesive.

As the nonwoven fabric constituting the second sheet 6, nonwoven fabrics produced by various production methods can be used, and for example, various nonwoven fabrics such as a hot-air nonwoven fabric in which thermal fusion points between fibers are formed by a hot-air method using a fiber web obtained by a carding method or an air-laid method, a hot-roll nonwoven fabric in which thermal fusion points between fibers are formed by a hot-roll method using a fiber web obtained by a carding method, a hot-embossing nonwoven fabric, a spunlace nonwoven fabric, and a needle-punched nonwoven fabric can be used.

In the absorbent body 4 of the incontinence pad 10 of the present embodiment, as shown in fig. 2(b), the compressed portions 43 obtained by embossing are formed in a scattered manner, and thereby a plurality of high-flexibility regions 5 having lower flexural rigidity than other portions are formed in the absorbent body 4 so as to extend in the longitudinal direction X.

More specifically, in the absorbent body 4, a plurality of compressed part rows R in which the compressed parts 43 are arranged in series at a predetermined pitch at intervals in the longitudinal direction X are formed in the width direction Y. The positions of the compressed portions 43 in the longitudinal direction X in the adjacent compressed portion rows R are shifted by a distance of half a pitch.

[ measurement method of flexural rigidity ]

Measurement of flexural rigidity manufactured by (strand) production suitable for JIS L1096 (general textile test method, confirmation 2004) rigid-soft E method: HOM-2 softness tester. On a sample stage of the testing machine in which the gap between the slits was adjusted to 30mm, a test piece (main body of the absorbent article) was horizontally arranged such that a measurement portion of the test piece was located at the center between the slits and a direction along the longitudinal direction of the main body was aligned with a direction along the gap. The test piece is not fixed on the sample table. The plate adjusted so as to be lowered to a position below 8mm from the surface of the sample stage (lowermost position) was moved from above the test piece at a constant speed: the 200mm/min drops. The maximum value (cN) indicated by an indicator (load meter) when the test piece is pressed back and forth in the longitudinal direction by the plate is read. The flexural rigidity was determined by taking 3 measurements on different test pieces and calculating the average value.

The compressing sections 43 in the present embodiment are formed by pressing between an embossing roll having cylindrical pressing projections on the peripheral surface and an anvil roll having a smooth surface, and the thickness of the absorbent body 4 is thinner in each compressing section 43 than in other sections. The surface of the absorbent body 4 on the non-skin contact surface side is the embossing roller side, and the compressed portion 43 has a concave portion in a planar shape corresponding to the shape of the distal end surface of the pressing projection on the surface of the absorbent body 4 on the non-skin contact surface side.

A region between a straight line L1 connecting one ends of the plurality of compressed parts 43 in the width direction and a straight line L2 connecting the other ends thereof in each compressed part row R becomes the high flexibility region 5. More specifically, in the absorbent body 4, a plurality of 2 types of compressed part rows R having different positions in the longitudinal direction X of the compressed parts 43 are alternately formed in the width direction Y, and the high flexibility regions 5a corresponding to one compressed part row R and the high flexibility regions 5b corresponding to the other compressed part row R are formed.

In the high flexibility region 5(5a, 5b), both end positions in the width direction of the absorbent body 4 in which the rigidity changes, that is, the position of the straight line L1 and the position of the straight line L2, are easily bent, and the high flexibility region 5 also includes both end positions in the width direction (the position of the straight line L1 and the position of the straight line L2).

The compressed portion 43 for forming the high flexibility region 5 may be formed only by pressing, or may be formed by heating simultaneously with pressing.

The number of the high flexibility regions 5 formed in the width direction Y of the absorbent body 4 is plural, preferably 5 or more, more preferably 8 or more, and further preferably 10 or more.

The length of the compression portion 43 and the high flexibility region 5 in the width direction Y is preferably 0.2mm or more, more preferably 0.5mm or more, and further preferably 10mm or less, more preferably 5mm or less. When the compressed portions 43 for forming the high flexibility region 5 are formed at intervals in the longitudinal direction X, the interval L3 between adjacent compressed portions 43 is preferably 2mm or more, more preferably 5mm or more, and further preferably 20mm or less, more preferably 10mm or less. The pitch P between the compressed part rows R adjacent in the width direction Y of the absorbent body 4 and the center positions of the high flexibility regions 5 is preferably 1mm or more, more preferably 3mm or more, and further preferably 10mm or less, more preferably 5mm or less.

As shown in fig. 2(a), the position of the concave portions 14 of the nonwoven fabric 1 constituting the topsheet 2 coincides with the position of the high flexibility regions 5 at a plurality of locations in the width direction Y in the absorbent body 4.

More specifically, the high flexibility region 5 extending in the longitudinal direction X is formed in a plurality of rows in the width direction Y, and the positions of the concave portions 14 and the positions of the high flexibility region 5 are continuously overlapped in the longitudinal direction X at a plurality of positions in the width direction Y. Here, the position of the concave portion 14 is the sheet thickness T of the nonwoven fabric 1_SThe bottom portion region 13c, which is the lower portion in the thickness direction in the trisection, is determined as the concave portion 14. The number of the concave portions 14 overlapping the high flexibility region 5 is plural, preferably 3 or more, more preferably 5 or more, and further preferably 8 or more.

According to the incontinence pad 10 of the present embodiment, since the absorbent body 4 is provided with the plurality of high flexibility regions 5 along the longitudinal direction X at intervals in the width direction Y, the front sheet 2 is easily bent in the width direction Y along the concave portions 14, and accordingly, as shown in fig. 7, the incontinence pad 10 is easily deformed so as to conform to the shape of the skin surface S of the wearer, and is excellent in the following property to the shape change of the skin surface S accompanying the movement of the wearer. Further, unlike the case where the absorbent body 4 is simply thinned and easily deformed, wrinkles are not easily generated in the absorbent body 4, and walking wrinkles are not easily generated in the skin contact surface including the topsheet 2, and therefore, a feeling of discomfort when worn is not easily generated.

Further, since the ridges 13 of the front sheet 2 of the incontinence pad 10 are hollow and easily swing in the width direction Y with the concave portions 14 joined to the lower sheet 6 as base points following the movement of the skin, and the nonwoven fabric 1 forming the ridges 13 is a nonwoven fabric including constituent fibers having a plurality of portions with different fiber diameters, when the ridges 13 are pressed by the skin, stress concentrates on the small-diameter portions and the portions of the ridges 13 are also deformed flexibly.

The incontinence pad 10 of the present embodiment is excellent in the following deformability with respect to the movement of the wearer, the uneasiness of the uncomfortable feeling, the feeling of the skin, and the like by the above-described action.

In the incontinence pad 10 of the present embodiment, as shown in fig. 6, the concave portions 14 of the topsheet 2 and the joining portions 14s of the lower side sheet 6 such as the second sheet are formed at intervals in the longitudinal direction X, so that the joining portions 14s and the non-joining portions 14t, that is, the portions of the topsheet 2 that are not joined to other members, are alternately formed in the longitudinal direction X, and it is preferable that at least some of the compressed portions 43 (see fig. 2(b) and the like) of the plurality of absorbent bodies 4 in the high flexibility region 5 of the absorbent body 4 are present at the same positions as the non-joining portions 14t in the topsheet 2. That is, the incontinence pad 10 preferably has an overlapping portion of the non-joined portion 14t of the topsheet 2 and the compressed portion 43 of the absorbent body 4 in a plan view as shown in fig. 6. In particular, regarding the high flexibility region 5 that coincides with the position of the concave portion 14 in the width direction Y, it is preferable that at least a part of the compressed portion 43 included in the high flexibility region 5 is present at the same position as the non-joined portion 14 t. Since the incontinence pad 10 has such an overlapping portion, the flexibility originally possessed by the high-flexibility region 5 is easily maintained, as compared with a case where, for example, most of the compressed portion 43 is present at the same position as the joint portion 14s, and therefore, the deformation of the incontinence pad 10 shown in fig. 7 can be more reliably achieved.

From the viewpoint of more reliably exhibiting the above-described operational effects due to the overlapping of the non-joined portions 14t of the topsheet 2 and the compressed portions 43 of the absorbent body 4, the ratio (the latter/former) × 100, preferably 50% or more, and more preferably 80% or more, of the total number of the compressed portions 43 formed in the absorbent body 4 (the total number of the compressed portions 43 formed on each surface when the compressed portions 43 are formed on both the skin contact surface and the non-skin contact surface of the absorbent body 4) is the number of the compressed portions 43 present at the same position as the non-joined portions 14t of the topsheet 2. In particular, the ratio is preferably 100%, that is, the mode in which all the compressed parts 43 of the absorbent body 4 overlap the non-joined parts 14t of the topsheet 2 (or do not overlap the joined parts 14 s).

Further, according to the incontinence pad 10 of the present embodiment, since the positions of the concave portions 14 coincide with the positions of the highly flexible regions 5 at a plurality of locations in the width direction Y in the absorbent body 4, "rubbing stimulus" in which the skin of the wearer is rubbed and stimulated during the skin movement of the wearer can be further reduced.

Further, since the compressed part rows 43 are formed in the absorbent body 4 to form the high flexibility regions 5, the absorbent body 4 having the high flexibility regions 5 can be easily manufactured, and an increase in the cost of the absorbent body 4 and the absorbent article due to the formation of the high flexibility regions 5 can be suppressed.

Further, since the lower sheet 6 to which the concave portions 14 of the top sheet 2 are joined is the second sheet 6 made of nonwoven fabric, the absorbent body 4 deformed by the high-flexibility regions 5 is easily restored to the original state, and the following ability to the movement of the skin is further excellent. From the above viewpoint, the nonwoven fabric constituting the second sheet 6 preferably has a three-dimensional network structure obtained by bonding short fibers, and is preferably a through-air nonwoven fabric, for example.

From the viewpoint of the follow-up deformability with respect to the movement of the skin, the grammage of the second sheet 6 is preferably 10g/m²Above and 40g/m²Hereinafter, more preferably 15g/m²Above and 30g/m²The following.

The second sheet 6 and the absorbent body 4, the layers of the absorbent sheet constituting the absorbent body 4, and the absorbent body 4 and the back sheet 3 are preferably bonded together with an adhesive. When the members are joined together with the adhesive, the entire coating may be performed by a slit coater or the like, but pattern coating is preferable. Preferable examples of the application pattern to be applied in a pattern include a spiral pattern, a dot pattern, a stripe pattern (striped pattern), a lattice pattern, and a checkered pattern.

Furthermore, as shown in fig. 5, when one of the constituent fibers 11 is focused on, the change point 18 that changes from the small diameter portion 16 adjacent to the welded portion 12 to the large diameter portion 17 is disposed within the range of 1/3 of the interval T between the adjacent welded portions 12, 12 from the welded portion 12, and therefore, the fiber is soft and has a good texture. In particular, when focusing attention on one constituent fiber 11, if a plurality of small diameter portions 16 are formed between adjacent welded portions 12, the tactile sensation of the skin becomes more favorable. From the viewpoint of easily exerting such an effect, the constituent fibers 11 are preferably composed of only high-elongation fibers (heat-extensible composite fibers).

The nonwoven fabric 1 has an uneven structure, and the fiber density of the wall portion 15 is formed to be smaller than the fiber density of the top portion of the convex portion 13 and the fiber density of the bottom portion of the concave portion 14. Therefore, the distance between fibers of the wall portion 15 is larger than the distance between fibers of the top of the convex portion 13 and the bottom of the concave portion 14, and therefore the air permeability of the nonwoven fabric 1 as a whole is improved. Further, the capillary force at the top of the raised portions 13 and the bottom of the recessed portions 14 is higher than that of the wall portions 15, and therefore, the moisture absorption is improved.

Next, another embodiment of the present invention will be described.

In the incontinence pad 10A shown in fig. 8, the nonwoven fabric 1 constituting the front sheet 2 is the same nonwoven fabric as the nonwoven fabric constituting the front sheet of the incontinence pad 10, but differs in that the lower sheet of the concave portion 14 joining the front sheet 2 is a core sheet 41. The present embodiment is the same as the incontinence pad 10 described above, and the description thereof is applied as appropriate.

In the incontinence pad 10A, the entire absorbent core 40 may be wrapped with one sheet of the core sheet 41, or the entire absorbent core 40 may be wrapped with 2 or more core sheets, and for example, the skin contact surface side and the non-skin contact surface side of the absorbent core 40 may be wrapped with different sheets.

The incontinence pad 10A can also exhibit the same effects as those of the incontinence pad 10 described above. As a covering sheet for covering the skin contact surface side of the absorbent core 40, a covering sheet having a grammage of 10g/m is preferably used²Above and 30g/m²The following sheet is more preferably used in a grammage of 15g/m²Above and 20g/m²The following tablets.

The nonwoven fabric used as the front sheet in the present invention is produced by a method for producing a nonwoven fabric, comprising the steps of: a fusion step of fusion-bonding intersection points of constituent fibers of a fiber mesh cloth including high-elongation fibers at a fusion-bonded portion to form a fiber sheet; and an extending step of extending the fiber sheet in one direction. An embodiment of a method for producing a nonwoven fabric used as a front sheet in the present invention will be described with reference to fig. 9, taking a preferred method for producing the nonwoven fabric 1 as an example. Fig. 9 schematically shows a preferred manufacturing apparatus 100 used in the method for manufacturing the nonwoven fabric 1. The manufacturing apparatus 100 is preferably applied to the manufacture of a hot-air nonwoven fabric. The manufacturing apparatus 100 includes a web forming portion 200, a hot air processing portion 300, an extending portion 400, and a lower sheet joining portion 500 in this order from the upstream side to the downstream side of the manufacturing step.

As shown in fig. 9, a web forming device 201 is disposed in the web forming portion 200. As the web forming device 201, a carding machine is used. As the carding machine, the same carding machine as that generally used in the technical field of absorbent articles can be used without particular limitation. Other web manufacturing devices, such as air laying devices, may also be used instead of carding machines, depending on the specific use of the nonwoven fabric 1.

As shown in fig. 9, the hot air processing unit 300 includes a cover 301. Inside the cover 301, hot air can be blown in a ventilation manner. The hot air processing unit 300 includes an endless conveyor belt 302 including an air-permeable net. The conveyor belt 302 rotates within the shroud 301. The conveyor belt 302 is formed of a resin such as polyethylene terephthalate or a metal.

The temperature and the heat treatment time of the hot air blown into the cover 301 are preferably adjusted so that the intersection points of the high-elongation fibers included in the constituent fibers 11 of the fiber mesh cloth 1b are thermally welded. More specifically, the temperature of the hot air is preferably adjusted to a temperature higher by 0 to 30 ℃ than the melting point of the resin having the lowest melting point in the constituent fibers 11 of the fiber mesh cloth 1 b. The heat treatment time is preferably adjusted to 1 second to 5 seconds depending on the temperature of the hot air. In addition, from the viewpoint of promoting further entanglement of the constituent fibers 11, the wind speed of the hot wind is preferably about 0.3 m/sec to 1.5 m/sec. The conveying speed is preferably about 5m/min to 100 m/min.

As shown in fig. 9 and 10, the extension 400 has a pair of concave- convex rollers 401 and 402 capable of engaging with each other. The pair of uneven rollers 401 and 402 are formed to be heatable, and the large-diameter convex portions 403 and 404 and the small-diameter concave portions (not shown) are alternately arranged in the roller axis direction. The uneven rollers 401 and 402 may or may not be heated, and the heating temperature when heating the uneven rollers 401 and 402 is preferably equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature in the high-elongation fibers and equal to or lower than the melting point of the resin having the lowest melting point in the high-elongation fibers, from the viewpoint of facilitating the elongation of the high-elongation fibers included in the constituent fibers 11 of the fiber sheet 1a described later. More preferably, the temperature is higher by 10 ℃ than the glass transition temperature of the fiber and lower by 10 ℃ than the melting point, and further preferably higher by 20 ℃ than the glass transition temperature of the fiber and lower by 20 ℃ than the melting point. For example, when the fibers of the core/sheath structure are heated using a PE (sheath) having a glass transition temperature of 67 ℃, a melting point of 258 ℃ in PET (core)/glass transition temperature of-20 ℃ and a melting point of 135 ℃, the temperature is preferably increased to 67 ℃ to 135 ℃, more preferably 77 ℃ to 125 ℃, and still more preferably 87 ℃ to 115 ℃.

In the manufacturing apparatus 100, as shown in fig. 10, the interval (pitch) between the large-diameter convex portions 403 and 403 adjacent to each other in the roller axis direction of the concavo-convex roller 401 and the interval (pitch) between the large-diameter convex portions 404 and 404 adjacent to each other in the roller axis direction of the concavo-convex roller 402 are the same interval (pitch) w, and the interval (pitch) w is preferably 1mm or more and 10mm or less, and particularly preferably 1.5mm or more and 8mm or less, from the viewpoint that the high-elongation fibers included in the constituent fibers 11 of the fiber sheet 1a are smoothly elongated in the elongation device, and the aforementioned change point from the small-diameter portion to the large-diameter portion is adjacent to the welded portion and the feel of the skin is good. From the same viewpoint, as shown in fig. 10, the press-fitting amount t (the distance between the apex of the large-diameter convex portion 403 and the apex of the large-diameter convex portion 404 adjacent to each other in the roller axis direction) of the pair of uneven rollers 401 and 402 is preferably 1mm or more and 3mm or less, and particularly preferably 1.2mm or more and 2.5mm or less. From the same viewpoint, the mechanical elongation ratio 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 lower sheet joining part 500 includes a concavo-convex roller 402 and a flat roller 501 having a smooth surface, and joins the nonwoven fabric 1 having the concavo-convex shape and the lower sheet by heating and pressing between the large-diameter convex part 404 of the concavo-convex roller 402 and the peripheral surface of the flat roller 501.

A method for producing the nonwoven fabric 1 using the production apparatus 100 having the above-described structure will be described.

First, as shown in fig. 9, a fiber web 1b is formed by a web forming device 201, which is a carding machine, using short-fiber constituent fibers 11 having high-elongation fibers as a raw material by a web forming portion 200 (web forming step). The fiber web 1b manufactured by the web forming device 201 is in a state in which the constituent fibers 11 thereof are loosely entangled with each other, and shape retention as a sheet has not yet been obtained.

Next, as shown in fig. 9, the intersection points of the constituent fibers 11 of the fiber mesh cloth 1b including the high-elongation fibers are heat-welded at the welding portion 12 to form the fiber sheet 1a (welding step). Specifically, the fiber web 1b is conveyed on the conveyor belt 302, and hot air is blown by the hot air processing unit 300 while passing through the cover 301. When the hot air is blown in the air flow manner, the constituent fibers 11 of the fiber mesh cloth 1b are further entangled with each other, and the intersections of the entangled fibers are thermally fused (see fig. 11 a), thereby producing the fiber sheet 1a having a sheet-like shape retention property.

Next, as shown in fig. 9, the fiber sheet 1a after welding is stretched in one direction (stretching step). Specifically, a fused fiber sheet 1a having shape retention as a sheet is conveyed between a pair of concavo- convex rollers 401 and 402, and as shown in fig. 11(a) to 11(c), the fiber sheet 1a is extended, a large diameter portion 17 having a large fiber diameter is formed between 2 small diameter portions 16 and 16 having a small fiber diameter in one constituent fiber 11 between adjacent fusion-joined portions 12 and 12, and a change point 18 is formed in a range of 1/3 of a distance T between the adjacent fusion-joined portions 12 and 12 from the fusion-joined portion 12, which is shifted from the small diameter portion 16 to the large diameter portion 17. More specifically, the fiber sheet 1a in which the intersections of the constituent fibers 11 shown in fig. 11(a) are heat-fused at the fusion-spliced portion 12 is conveyed between the pair of uneven rollers 401 and 402, and the fiber sheet 1a is extended in the direction (CD, roll axis direction) orthogonal to the machine direction (MD, traveling direction). When the fiber sheet 1a extends in the orthogonal direction (CD, roll axis direction), the region between the adjacent fusion-spliced portions 12, 12 shown in fig. 11(a) that fix the constituent fibers 11 to each other is actively extended in the orthogonal direction (CD, roll axis direction). In particular, as shown in fig. 11(b), local contraction is likely to occur first in the vicinity of each fusion-bonded portion 12 that fixes the constituent fibers 11 to each other, and 2 small diameter portions 16, 16 are formed at both ends of one constituent fiber 11 between the adjacent fusion-bonded portions 12, and a portion sandwiched by the 2 small diameter portions 16, 16 becomes a large diameter portion 17, and a large diameter portion 17 sandwiched by the 2 small diameter portions 16, 16 is formed. Since local contraction is likely to occur first in the vicinity of each welded portion 12 in this manner, the change point 18 from the small diameter portion 16 to the large diameter portion 17 is formed within the range of 1/3 of the interval T between the adjacent welded portions 12, 12 from the welded portion 12.

As shown in fig. 11 c, one constituent fiber 11 between some adjacent fusion-bonded portions 12, 12 extends in the orthogonal direction (CD, roll axis direction) while leaving a space (extension range) in which the fiber can be extended, and a large diameter portion 17 between the adjacent fusion-bonded portions 12, 12 extends, and a plurality of small diameter portions 16 are formed in the large diameter portion 17.

As described above, according to the method for producing the nonwoven fabric 1 using the production apparatus 100, the nonwoven fabric 1 having the constituent fibers 11 shown in fig. 5 can be produced continuously and efficiently. The nonwoven fabric 1 thus produced is directly conveyed to the sheet joining portion of the lower sheet joining portion 500 in a state of being deformed into an uneven shape by the uneven roller 402. The band-shaped nonwoven fabric 6 for the second sheet, which is unwound from the roll-shaped wound product 6', is supplied to the sheet merging portion, and the uneven nonwoven fabric 1 is introduced between the uneven roller 402 and the flat roller 501 in a state of being overlapped with the band-shaped nonwoven fabric 6. Between the concave-convex roller 402 and the flat roller 501, the concave portions of the concave-convex nonwoven fabric 1 and the belt-like nonwoven fabric 6 are bonded by heating and pressing between the large-diameter convex portions 404 of the concave-convex roller 402 and the peripheral surface of the flat roller 501. In this way, a belt-shaped composite sheet 8 is obtained in which the front sheet 2 including the nonwoven fabric 1 is joined to the lower sheet 6 at the concave portions 14. The strip-shaped composite sheet 8 is introduced into the production line of the incontinence pad 10 after being wound or introduced into the production line of the incontinence pad 10 without being wound.

The incontinence pad 10 is obtained by arranging the absorbent body 4 having the compressed portions 43 formed by embossing between the belt-shaped composite sheet 8 and the belt-shaped back sheet 3 such that the positions of the highly flexible regions formed by the compressed portions 43 coincide with the positions of the concave portions of the front sheet 2, and then cutting the absorbent body into the shape of each article.

The absorbent article of the present invention is not limited to the above-described embodiment, and can be modified as appropriate.

For example, the highly flexible region of the absorbent body 4 can also be formed by forming the compressed sections 43 in the absorbent body 4 in the pattern shown in fig. 12(a) to 12 (c). In fig. 12(a), the compressed portions 43 are configured such that the length in the longitudinal direction X of the incontinence pad 10 is longer than the interval L3 between adjacent compressed portions 43. In fig. 12(b), the compressed portion 43 is formed continuously in the longitudinal direction X of the incontinence pad 10. In fig. 12(c), the shape of the compressed portion 43 is the same as the dot shape in the present embodiment described above, but the positions in the longitudinal direction X of the compressed portions 43 in the adjacent compressed portion rows R (high flexibility regions 5) are the same.

Furthermore, the absorbent article of the invention may also be a catamenial tampon or panty liner instead of an incontinence pad. The length of the absorbent article including the second sheet 6 of nonwoven fabric in one or both of the longitudinal direction X and the width direction Y may be the same as that of the topsheet 2 or may be shorter than that of the topsheet 2. Further, the absorbent article may not have the leakage preventing cuffs.

The absorbent body in the present invention may be constituted by an absorbent sheet 42 as in the absorbent body 4 shown in fig. 13. The absorbent member 4 shown in fig. 13 includes a laminate in which 2 or more layers of absorbent sheets 42 are laminated. The laminate having 2 or more layers may be a laminate obtained by folding one absorbent sheet and bonding these layers, or may be a laminate obtained by laminating a plurality of individual absorbent sheets. Further, an absorbent sheet added between layers or on one surface of a laminate having 2 or more layers may be used as the absorbent body, which is partially formed thick. As the absorbent sheet, an absorbent sheet comprising a fibrous material and a water-absorbent polymer is preferably used. Further, as the absorbent sheet, a sheet-like structure can be preferably used in which the constituent fibers are bonded to each other or to each other and the constituent fibers and the water-absorbent polymer are bonded to each other by using the adhesive force of the water-absorbent polymer in a wet state or a separately added adhesive or a binder such as an adhesive fiber. As the absorbent sheet, there can be used an absorbent sheet produced by the method described in japanese unexamined patent publication No. 8-246395, a dry sheet in which pulverized pulp supplied with an air stream and a water-absorbent polymer are stacked and fixed with an adhesive (for example, a vinyl acetate-based adhesive, PVA, or the like), an absorbent sheet in which a highly water-absorbent polymer is dispersed after a hot-melt adhesive or the like is applied between paper or nonwoven fabric, an absorbent sheet in which a highly water-absorbent polymer is blended in a spun-bonded or melt-blown nonwoven fabric production step, or the like. These absorbent sheets can also be used as an absorbent body having a single-layer structure without stacking 2 or more layers. Further, the layers may not be joined at the time of lamination.

The following absorbent article is further disclosed with respect to the above embodiment.

＜1＞

An absorbent article having a liquid-permeable front sheet and a back sheet forming a skin-contacting surface, and an absorbent body interposed between the two sheets, and having a longitudinal direction and a width direction, the absorbent article characterized in that:

the front sheet comprises a nonwoven fabric having a concavo-convex structure in which stripe-shaped ridges and valleys extending in the longitudinal direction are alternately arranged in the width direction, the valleys are joined to the adjacent lower side sheet, the ridges have a hollow structure between the ridges and the lower side sheet,

the nonwoven fabric comprises fibers having a large diameter portion and a small diameter portion having different fiber diameters,

the absorbent body has high flexibility regions having lower flexural rigidity than other portions at a plurality of locations in the width direction.

＜2＞

The absorbent article according to the above < 1 >, wherein the positions of the concave portions coincide with the positions of the high flexibility regions at a plurality of locations in the width direction.

＜3＞

The absorbent article according to the above < 2 >, wherein the high flexibility region extending in the longitudinal direction is formed in a plurality of rows in the width direction, and the positions of the concave portions and the positions of the high flexibility region are continuously overlapped in the longitudinal direction at a plurality of locations in the width direction.

＜4＞

The absorbent article according to any one of the above items < 1 > to < 3 >, wherein the high flexibility region is formed by compression of the absorbent body.

＜5＞

The absorbent article according to the above < 4 >, wherein a plurality of compressed sections of the absorbent body are formed in series in the longitudinal direction in the high flexibility region.

＜6＞

The absorbent article according to any one of the above items < 1 > to < 5 >, wherein, in the absorbent body, as the high flexibility region, a plurality of compressed part rows in which compressed parts are arranged in series at intervals in the longitudinal direction are formed in the width direction, and the positions of the compressed parts in the longitudinal direction in adjacent compressed part rows are shifted by half a pitch.

＜7＞

The absorbent article according to any one of the above < 1 > to < 5 >, wherein, in the absorbent body, as the high flexibility region, a plurality of compressed part rows in which compressed parts are arranged in series at intervals in the longitudinal direction are formed in the width direction, and the positions in the longitudinal direction of the compressed parts in the adjacent compressed part rows are the same.

＜8＞

The absorbent article according to any one of the above items < 5 > to < 7 >, wherein the length of the compressed portions in the longitudinal direction is greater than the interval between adjacent compressed portions in the longitudinal direction.

＜9＞

The absorbent article according to any one of the above items < 1 > to < 5 >, wherein the absorbent body has a compressed portion formed as the high flexibility region and continuous in the longitudinal direction.

＜10＞

The absorbent article according to any one of the above items < 1 > to < 9 >, wherein the number of the high flexibility regions formed in the width direction of the absorbent body is plural, preferably 5 or more, more preferably 8 or more, and still more preferably 10 or more.

＜11＞

The absorbent article according to any one of the above items < 1 > to < 10 >, wherein the length of the high flexibility region in the width direction is preferably 0.2mm or more, more preferably 0.5mm or more, and further preferably 10mm or less, more preferably 5mm or less.

＜12＞

The absorbent article according to any one of the above items < 1 > to < 11 >, wherein the compressed portions for forming the high flexibility region are formed at intervals in the longitudinal direction, and the interval between the compressed portions adjacent in the longitudinal direction is preferably 2mm or more, more preferably 5mm or more, and further preferably 20mm or less, more preferably 10mm or less.

＜13＞

The absorbent article according to any one of the above items < 1 > to < 12 >, wherein a pitch between central positions of the high flexibility regions adjacent in the width direction of the absorbent body is preferably 1mm or more, more preferably 3mm or more, and further preferably 10mm or less, more preferably 5mm or less.

＜14＞

The absorbent article according to any one of the above items < 1 > to < 13 >, wherein the number of the concave portions overlapping the high flexibility region is plural, preferably 3 or more, more preferably 5 or more, and still more preferably 8 or more.

＜15＞

The absorbent article according to any one of the above < 1 > to < 14 >, wherein the thickness of the absorbent body is preferably 1mm or more, more preferably 2mm or more, and further preferably 15mm or less, more preferably 10mm or less, and further preferably 1mm or more and 15mm or less, and further preferably 2mm or more and 10mm or less.

＜16＞

The absorbent article according to any one of the above items < 1 > to < 15 >, wherein the nonwoven fabric includes a plurality of fusion portions formed by thermally fusing intersections of the constituent fibers.

＜17＞

The absorbent article according to any one of the above items < 1 > to < 16 >, wherein the constituent fibers of the nonwoven fabric include high-elongation fibers.

＜18＞

The absorbent article according to the above < 17 >, wherein the high-elongation fiber is a core-sheath composite fiber having heat-fusion properties.

＜19＞

The absorbent article according to < 17 > or < 18 > above, wherein the fineness of the high-elongation fibers is 1.0dtex or more and 10.0dtex or less, preferably 2.0dtex or more and 8.0dtex or less at the stage of raw material.

＜20＞

The absorbent article according to any one of the above < 17 > to < 19 >, wherein the ratio of the high-elongation fibers in the nonwoven fabric is 50% by mass or more and 100% by mass or less, preferably 80% by mass or more and 100% by mass or less.

＜21＞

The absorbent article according to any one of the above < 17 > to < 20 >, wherein the elongation of the high-elongation fiber is preferably 100% or more and 800% or less, more preferably 200% or more and 500% or less, and further preferably 250% or more and 400% or less at the stage of the raw material.

＜22＞

The absorbent article according to any one of the above < 1 > to < 21 >, wherein, when attention is paid to one constituent fiber of the nonwoven fabric, a large diameter portion having a large fiber diameter is provided between adjacent fused portions, the large diameter portion being sandwiched between 2 small diameter portions having a small fiber diameter.

＜23＞

The absorbent article according to the above < 22 >, wherein the one constituent fiber has a plurality of large diameter portions between adjacent welded portions.

＜24＞

The absorbent article according to the above < 22 > or < 23 >, wherein the constituent fibers of the nonwoven fabric have 1 or more and 5 or less large diameter portions, preferably 1 or more and 3 or less large diameter portions, between adjacent fused portions when focusing attention on one constituent fiber.

＜25＞

The absorbent article according to any one of the above < 22 > to < 24 >, wherein the fiber diameter (diameter L) of the small diameter portion₁₆) The diameter of the fiber (diameter L) relative to the large diameter part₁₇) Ratio (L) of₁₆/L₁₇) Is 0.5 to 0.8 inclusive, and more preferably 0.55 to 0.7 inclusive.

＜26＞

The absorbent article according to any one of the above items < 22 > to < 25 >, wherein the fiber diameter (diameter L) of the small diameter portion₁₆) Preferably 5 to 28 μm, more preferably 6.5 to 20 μm, and particularly preferably 7.5 to 16 μm.

＜27＞

As aboveThe absorbent article according to any one of the above-mentioned items < 22 > to < 26 >, wherein the fiber diameter (diameter L) of the large diameter portion₁₇) Preferably 10 to 35 μm, more preferably 13 to 25 μm, and particularly preferably 15 to 20 μm.

＜28＞

The absorbent article according to any one of the above items < 22 > to < 27 >, wherein, when attention is paid to one constituent fiber, the change point at which the constituent fiber of the nonwoven fabric changes from the small-diameter portion adjacent to the welded portion to the large-diameter portion is disposed within a range of 1/3 of the interval between adjacent welded portions from the welded portion.

＜29＞

The absorbent article according to any one of the above items < 1 > to < 28 >, wherein the nonwoven fabric includes a top region, a bottom region, and a side region located therebetween when viewed in a cross section in the thickness direction.

＜30＞

The absorbent article according to the above < 29 >, wherein the fiber density of the side region is formed lower than the fiber density of the top region and the fiber density of the bottom region.

＜31＞

The absorbent article according to the above < 29 >, wherein the nonwoven fabric has a minimum fiber density in the side regions.

＜32＞

The absorbent article according to any one of the above items < 29 > to < 31 >, wherein the fiber density (D) of the side region_13c) Fiber density (D) relative to the top area_13a) Or the fiber density (D) of the above-mentioned bottom region_13b) Ratio (D)_13c/D_13a，D_13c/D_13b) Is 0.15 to 0.9 inclusive, and more preferably 0.2 to 0.8 inclusive.

＜33＞

The absorbent article according to any one of the above < 29 > to < 32 >, wherein the top region has a fiber density (D)_13a) Preferably 90 roots/mm²Above and 200 pieces/mm²The number of the cells is preferably 100/mm or less²Above 180 pieces/mm²The following.

＜34＞

The absorbent article according to any one of the above < 29 > to < 33 >, wherein the bottom region has a fiber density (D)_13b) Preferably 80 roots/mm²Above and 200 pieces/mm²Less than 90 pieces/mm is more preferable²Above 180 pieces/mm²The following.

＜35＞

The absorbent article according to any one of the above items < 29 > to < 34 >, wherein the fiber density (D) of the side region_13c) Preferably 30 roots/mm²Above 80 roots/mm²The number of the cells is preferably 40/mm or less²Above 70 roots/mm²The following.

＜36＞

The absorbent article according to any one of the above < 29 > to < 35 >, wherein the nonwoven fabric includes a fused portion formed by thermally fusing intersecting points of the constituent fibers,

the number of fibers having a change point from a small diameter portion adjacent to the welded portion to a large diameter portion among the constituent fibers constituting the side region is set to be larger than the number of fibers having the change point among the constituent fibers constituting the top region and the number of fibers having the change point among the constituent fibers constituting the bottom region.

＜37＞

The absorbent article according to any one of the above < 29 > to < 36 >, wherein the nonwoven fabric includes a fused portion formed by thermally fusing intersecting points of the constituent fibers,

the number of fibers having a change point from a small diameter portion adjacent to the welded portion to a large diameter portion (N) among the constituent fibers constituting the side region_13c) The number of fibers having the change point (N) among the constituent fibers constituting the top region_13a) Or the number of fibers having the change point (N) among the constituent fibers constituting the bottom region_13b) Ratio (N)_13c/N_13a，N_13c/N_13b) Is 2 to 20 inclusive.

＜38＞

The absorbent article according to any one of the above items < 29 > to < 37 >, wherein, regarding a specific value of the number of fibers having a change point in the nonwoven fabric, the number of fibers having a change point (N) in the constituent fibers constituting the top region_13a) Preferably 1 to 15, and more preferably 5 to 15.

＜39＞

The absorbent article according to any one of the above items < 29 > to < 38 >, wherein, regarding a specific value of the number of fibers having a change point in the nonwoven fabric, the number of fibers having a change point (N) in the constituent fibers constituting the bottom region_13b) Preferably 1 to 15, and more preferably 5 to 15.

＜40＞

The absorbent article according to any one of the above items < 29 > to < 39 >, wherein, regarding a specific value of the number of fibers having a change point in the nonwoven fabric, the number of fibers having a change point (N) in the constituent fibers constituting the side region_13c) Preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less.

＜41＞

The absorbent article according to any one of the above < 1 > to < 40 >, wherein the sheet thickness of the nonwoven fabric is 0.5mm or more and 7mm or less, preferably 1.0mm or more and 5mm or less.

＜42＞

The absorbent article according to any one of the above items < 1 > to < 41 >, wherein the layer thickness of the top region is 0.1mm or more and 3.0mm or less, preferably 0.2mm or more and 2.0mm or less.

＜43＞

The absorbent article according to any one of the above items < 1 > to < 42 >, wherein the layer thickness of the bottom region is 0.1mm or more and 3.0mm or less, preferably 0.2mm or more and 2.0mm or less.

＜44＞

The absorbent article according to any one of the above items < 1 > to < 43 >, wherein the layer thickness of the side region is 0.1mm or more and 3.0mm or less, preferably 0.2mm or more and 2.0mm or less.

＜45＞

The absorbent article according to any one of the above items < 1 > to < 44 >, wherein the pitch between the tops of the ridge portions adjacent in the width direction is 1mm or more and 15mm or less, preferably 1.5mm or more and 10mm or less.

＜46＞

The absorbent article according to any one of the above items < 1 > to < 45 >, wherein the grammage of the nonwoven fabric is 15g/m when expressed as an average value of the whole sheet²Above and 50g/m²Hereinafter, it is preferably 20g/m²Above and 40g/m²The following.

＜47＞

The absorbent article according to any one of the above items < 1 > to < 46 >, wherein the concave portions of the front sheet and the joining portions of the lower sheet are formed at intervals in the longitudinal direction of the absorbent article.

＜48＞

The absorbent article according to < 47 >, wherein the concave portions of the front sheet and the joined portions of the lower sheet are formed at intervals in the longitudinal direction, whereby the joined portions and the non-joined portions are alternately formed in the longitudinal direction in the front sheet, and a plurality of compressed portions of the absorbent body are formed in series in the longitudinal direction in the high flexibility region,

at least a part of the compressed parts of the plurality of absorbent bodies in the high-flexibility region are present at the same position as the non-joined part.

＜49＞

The absorbent article according to any one of the above items < 1 > to < 48 >, wherein a second sheet comprising a nonwoven fabric is disposed between the top sheet and the absorbent body, the second sheet being the lower sheet.

＜50＞

The absorbent article according to the above < 49 >, wherein the length of the second sheet in the longitudinal direction and the width direction is shorter than the topsheet.

＜51＞

The absorbent article according to the above < 49 > or < 50 >, wherein the nonwoven fabric constituting the second sheet has a three-dimensional network structure obtained by bonding short fibers.

＜52＞

The absorbent article according to any one of the above items < 49 > to < 51 >, wherein the grammage of the second sheet is 10g/m²Above and 40g/m²Hereinafter, it is preferably 15g/m²Above and 30g/m²The following.

＜53＞

An absorbent article according to any one of the above items < 1 > to < 48 >, wherein the absorbent body includes an absorbent core and a core-wrapped sheet wrapping the absorbent core, and the core-wrapped sheet is the lower side sheet.

＜54＞

The absorbent article according to < 53 > above, wherein the core-wrapped sheet has a grammage of 10g/m²Above and 30g/m²Hereinafter, it is preferably 15g/m²Above and 20g/m²The following.

Industrial applicability

The absorbent article of the present invention has excellent deformability following the movement of the wearer, less uncomfortable feeling generation property, and good texture.

Claims (31)

1. An absorbent article having a liquid-permeable front sheet and a back sheet forming a skin-contacting surface, and an absorbent body interposed between the two sheets, and having a longitudinal direction and a width direction, the absorbent article characterized in that:

the front sheet comprises a nonwoven fabric having a concavo-convex structure in which stripe-shaped ridges and valleys extending in the longitudinal direction are alternately arranged in the width direction, the valleys are joined to the adjacent lower side sheet, the ridges have a hollow structure between the ridges and the lower side sheet,

the nonwoven fabric comprises fibers having a large diameter portion and a small diameter portion which have different fiber diameters, the absorbent body has high flexibility regions having lower flexural rigidity than other portions at a plurality of locations in the width direction,

the nonwoven fabric includes a plurality of fusion parts formed by thermally fusing intersection points of the constituent fibers,

when focusing attention on one constituent fiber, the constituent fiber of the nonwoven fabric has the large diameter portion having a large fiber diameter sandwiched by the 2 small diameter portions having a small fiber diameter between the adjacent fusion-bonded portions.

2. The absorbent article of claim 1, wherein:

the position of the concave portion coincides with the position of the high flexibility region at a plurality of positions in the width direction.

3. The absorbent article of claim 2, wherein:

the high flexibility region extending in the longitudinal direction is formed in a plurality of rows in the width direction, and the positions of the concave portions and the positions of the high flexibility region are continuously overlapped in the longitudinal direction at a plurality of locations in the width direction.

4. The absorbent article according to any one of claims 1 to 3, wherein:

the highly flexible region is formed by compression of the absorbent body.

5. The absorbent article of claim 4, wherein:

in the high flexibility region, a plurality of compressed sections of the absorber are formed in series in the longitudinal direction.

6. The absorbent article of claim 5, wherein:

the concave portions of the front sheet and the joint portions of the lower sheet are formed at intervals in the longitudinal direction, so that the joint portions and the non-joint portions are alternately formed in the longitudinal direction in the front sheet, and at least some of the compressed portions of the plurality of absorbent bodies in the high-flexibility region are present at the same positions as the non-joint portions.

7. The absorbent article according to any one of claims 1 to 3, wherein:

in the absorbent body, as the high flexibility region, a plurality of compressed part rows in which compressed parts are arranged in series at intervals in the longitudinal direction are formed in the width direction, and the positions of the compressed parts in the adjacent compressed part rows in the longitudinal direction are shifted by a distance of half a pitch.

8. The absorbent article according to any one of claims 1 to 3, wherein:

in the absorbent body, as the high flexibility region, a plurality of compressed part rows in which the compressed parts are arranged in series at intervals in the longitudinal direction are formed in the width direction, and the positions in the longitudinal direction of the compressed parts in the adjacent compressed part rows are the same.

9. The absorbent article of claim 5, wherein:

the length of the compression parts in the longitudinal direction is greater than the interval between adjacent compression parts in the longitudinal direction.

10. The absorbent article according to any one of claims 1 to 3, wherein:

in the absorbent body, a compressed portion that is continuous in the longitudinal direction is formed as the high flexibility region.

11. The absorbent article according to any one of claims 1 to 3, wherein:

the number of the high flexibility regions formed in the width direction of the absorbent body is 5 or more.

12. The absorbent article according to any one of claims 1 to 3, wherein:

the length of the high flexibility region in the width direction is 0.2mm to 10 mm.

13. The absorbent article according to any one of claims 1 to 3, wherein:

the compressed portions for forming the high flexibility region are formed at intervals in the longitudinal direction, and the interval between adjacent compressed portions in the longitudinal direction is 2mm to 20 mm.

14. The absorbent article according to any one of claims 1 to 3, wherein:

the pitch between the center positions of the high flexibility regions adjacent in the width direction of the absorbent body is 1mm to 10 mm.

15. The absorbent article according to any one of claims 1 to 3, wherein:

the number of the concave portions overlapping the high flexibility region is 3 or more.

16. The absorbent article according to any one of claims 1 to 3, wherein:

the constituent fibers of the nonwoven fabric include high-elongation fibers.

17. The absorbent article of claim 16, wherein:

the extensibility of the high-extensibility fiber is more than 100% and less than 800% in the stage of raw material.

18. The absorbent article of claim 1, wherein:

the one constituent fiber has a plurality of the large diameter portions between the adjacent fusion-bonded portions.

19. The absorbent article of claim 1, wherein:

the fiber diameter (diameter L) of the small diameter part₁₆) A fiber diameter (diameter L) relative to the large diameter portion₁₇) Ratio (L) of₁₆/L₁₇) Is 0.5 to 0.8 inclusive.

20. The absorbent article of claim 1, wherein:

when focusing attention on one constituent fiber, the constituent fiber of the nonwoven fabric is arranged in the range of 1/3 of the interval between adjacent welded portions from the welded portion, at the point of change from the small diameter portion adjacent to the welded portion to the large diameter portion.

21. The absorbent article according to any one of claims 1 to 3, wherein:

the nonwoven fabric includes a top region, a bottom region, and side regions therebetween when viewed in cross section in the thickness direction.

22. The absorbent article of claim 21, wherein:

the fiber density of the side region is formed to be lower than the fiber density of the top region and the fiber density of the bottom region.

23. The absorbent article of claim 21, wherein:

the fiber density of the side regions in the nonwoven fabric is made to be the smallest.

24. The absorbent article of claim 21, wherein:

fiber density (D) of the side region_13c) Fiber density (D) relative to the top area_13a) Or the fiber density (D) of the bottom region_13b) Ratio (D)_13c/D_13a，D_13c/D_13b) Is 0.15 to 0.9 inclusive.

25. The absorbent article of claim 21, wherein:

the nonwoven fabric comprises a fusion part formed by fusion-bonding the intersection points of the fibers,

the number of fibers having a change point from a small diameter portion adjacent to the welded portion to a large diameter portion among the constituent fibers constituting the side region is made larger than the number of fibers having the change point among the constituent fibers constituting the top region and the number of fibers having the change point among the constituent fibers constituting the bottom region.

26. The absorbent article of claim 21, wherein:

the nonwoven fabric comprises a fusion part formed by fusion-bonding the intersection points of the fibers,

the number of fibers having a change point from a small diameter portion adjacent to the welded portion to a large diameter portion (N) among the constituent fibers constituting the side region_13c) Relative to the number (N) of fibers having the change point among the constituent fibers constituting the top region_13a) Or the number (N) of fibers having the change point among the constituent fibers constituting the bottom region_13b) Ratio (N)_13c/N_13a，N_13c/N_13b) Is 2 to 20 inclusive.

27. The absorbent article according to any one of claims 1 to 3, wherein:

the concave portions of the top sheet and the joining portions of the bottom sheet are formed at intervals in the longitudinal direction of the absorbent article.

28. The absorbent article according to any one of claims 1 to 3, wherein:

a second sheet including a nonwoven fabric is disposed between the front sheet and the absorbent body, and the second sheet is the lower sheet.

29. The absorbent article of claim 28, wherein:

the length of the second sheet in the longitudinal direction and the width direction is shorter than the front sheet.

30. The absorbent article of claim 28, wherein:

the nonwoven fabric constituting the second sheet has a three-dimensional network structure in which short fibers are bonded.

31. The absorbent article according to any one of claims 1 to 3, wherein:

the absorbent body includes an absorbent core and a core-spun sheet wrapping the absorbent core, the core-spun sheet being the lower side sheet.

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