TWI683655B - Absorbent article - Google Patents

Abstract

The front sheet (2) includes a nonwoven fabric (1) having a concave-convex structure in which stripe-shaped convex stripe portions (13) and concave stripe portions (14) extending in the longitudinal direction are alternately arranged in the width direction Y. The front sheet (2) is joined to the adjacent lower sheet (6) at the recessed portion (14). The nonwoven fabric (1) uses at least high-elongation fiber as a raw material. The lower sheet (6) contains an aggregate of fibers of thermoplastic resin. The convex strip part (13) has a hollow structure. The fiber density of the side region (14c) of the convex strip part (13) is lower than either of the fiber density of the top region (13a) and the fiber density of the bottom region (13b).

Description

Absorbent article

The invention relates to an absorbent article such as menstrual sanitary napkin or disposable diaper.

As a front sheet of an absorbent article, there is known a concavo-convex structure having stripe-shaped convex stripe portions and concave stripe portions extending in one direction alternately arranged in the width direction. For example, the present applicant proposes a front sheet formed by forming a plurality of fold-like portions parallel to each other and forming a concave-convex sheet for linear connection between the fold-like portions to a base material sheet (see Patent Document 1) .

Patent Document 2 describes a front sheet formed of a liquid-permeable fiber nonwoven fabric and shaped into a wave shape. The wave shape is continuously formed along the longitudinal direction of the front sheet. The top and bottom of the wave shape extend in a direction crossing the longitudinal direction of the front sheet. The fiber density of the wall region between the top region and the bottom region of the wave shape is lower than that of the top region or the bottom region.

Patent Document 3 describes a front sheet having ridge-shaped convex portions that are continuous in the longitudinal direction of the absorbent article at specific intervals in the width direction of the absorbent article. On both sides of each convex portion, at intervals in the longitudinal direction of the absorbent article, dot-shaped concave embossments are alternately applied to the right-side adjacent position and the left-side adjacent position, and the concave embossments are arranged in a staggered manner as a whole.

[Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2002-165830

Patent Document 2: Japanese Patent Laid-Open No. 2008-113866

Patent Document 3: Japanese Patent Laid-Open No. 2013-244256

According to the front sheet of Patent Document 1, a liquid having a relatively high viscosity absorbed between fold-like portions can be isolated from the wearer's skin. However, it is desired to further improve the absorbability when a large amount of urine or a relatively low-viscosity liquid is supplied. Also, in the technology described in Patent Document 2, since the convex and concave portions extending in the width direction of the absorbent article are formed on the front sheet, when a large amount of liquid is supplied, there are leakages from both ends in the width direction (The so-called side leakage) may cause sticky feeling on the wearer's skin.

Furthermore, in the technology described in each of the above patent documents, since the convex and concave portions extending in either the longitudinal direction or the width direction of the absorbent article are formed on the front sheet, the air permeability in this direction is ensured, But with regard to the direction orthogonal to it, the convex portion becomes a barrier to ventilation. In this way, in the prior art, it is difficult to ensure sufficient air permeability in both the longitudinal direction and the width direction on the skin facing side of the absorbent article.

The present invention provides an absorbent article having a liquid-permeable front sheet, a back sheet, and an absorber interposed between these two sheets that form a skin contact surface, and has a longitudinal direction and a width direction.

The front surface sheet includes a nonwoven fabric of a concave-convex structure in which stripe-shaped convex stripe portions and concave stripe portions extending in the longitudinal direction are alternately arranged in the width direction, and the adjacent lower sheet material is joined to the concave stripe portion.

The nonwoven fabric is made of at least high-elongation fiber as a raw material.

The lower sheet contains an aggregate of fibers of thermoplastic resin.

The ridge portion has a hollow structure between the non-woven fabric and the lower sheet.

The non-woven fabric has a top area, a bottom area, and a side portion between them In the region, the top of the convex strip part is formed by the top region, and the bottom of the concave strip part is formed by the bottom region.

The fiber density of the side region is lower than any of the fiber density of the top region and the fiber density of the bottom region.

1‧‧‧nonwoven

1a‧‧‧fiber sheet

1b‧‧‧fiber web

2‧‧‧Front sheet

3‧‧‧Back sheet

4‧‧‧Absorber

4a‧‧‧Side edge

6‧‧‧Lower sheet

6a‧‧‧Non-joined part

6'‧‧‧winding

7‧‧‧Perimeter

8‧‧‧Leak proof flanging

8a‧‧‧free end

8b‧‧‧Fixed area

8c‧‧‧Elastic member

8d‧‧‧elastic zone

10‧‧‧Sanitary pad

10A‧‧‧front area

10B‧‧‧ Rear area

10C‧‧‧Central area

11‧‧‧ Fiber

12‧‧‧Fusion Department

13‧‧‧Projection

13a‧‧‧Top area

13b‧‧‧Bottom area

13c‧‧‧Side area

14‧‧‧recessed part

14s‧‧‧Joint

16‧‧‧small diameter part

17‧‧‧ Major Diameter Department

18‧‧‧ change point

40‧‧‧absorbent core

41‧‧‧Package chips

42‧‧‧absorbent sheet

43‧‧‧High Density Department

44‧‧‧Low Density Department

100‧‧‧Manufacturing device

200‧‧‧Web forming department

201‧‧‧Net forming device

300‧‧‧Hot Air Treatment Department

301‧‧‧ cover

302‧‧‧Conveyor belt

400‧‧‧Extension

401‧‧‧Convex roller

402‧‧‧Convex roller

403‧‧‧Large diameter convex

404‧‧‧Large diameter convex

500‧‧‧Lower sheet joint

501‧‧‧Smooth roller

a, b‧‧‧ both sides

A‧‧‧Liquid

B‧‧‧Liquid

AT‧‧‧Region

BT‧‧‧Region

CT‧‧‧Central area

H‧‧‧ Height

L3‧‧‧Length

L5‧‧‧Total length

t‧‧‧Pressing amount

T‧‧‧Interval

w‧‧‧Interval

X‧‧‧length direction

Y‧‧‧Width direction

Z‧‧‧thickness direction

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

FIG. 2 is an enlarged cross-sectional view taken along line II-II of FIG. 1.

Fig. 3 is a cross-sectional view of an absorbent body used in the sanitary pad shown in Fig. 1.

4 is a partially broken perspective view showing an enlarged main part of the skin facing side of the sanitary pad shown in FIG. 1.

FIG. 5 is an enlarged schematic view of the main part in FIG. 4.

FIG. 6 is a diagram illustrating a state where constituent fibers constituting the nonwoven fabric shown in FIG. 4 are fixed to each other by a heat fusion part.

7 is a plan view of the opposite side of the skin of the sanitary pad shown in FIG. 1.

FIG. 8 is a schematic view showing a manufacturing apparatus preferably used for manufacturing the nonwoven fabric shown in FIG. 4.

9 is a cross-sectional view taken along line IX-IX shown in FIG. 8.

10(a), 10(b), and 10(c) are explanatory diagrams illustrating a case where a plurality of small-diameter portions and large-diameter portions are formed in one constituent fiber between adjacent fusion-bonding portions.

11 is a perspective view showing an incontinence pad as another embodiment of the present invention.

FIG. 12(a) is an enlarged cross-sectional view taken along the line II-II of FIG. 11, and FIG. 12(b) is a view showing the back surface (the surface on the non-skin contact surface side) of the absorbent body of the incontinence pad shown in FIG.

Fig. 13 is a partially broken perspective view showing the main part of the incontinence pad shown in Fig. 11 enlarged.

14 is an enlarged plan view showing a partial selection of the skin contacting surface of the incontinence pad showing an arrangement example of the junction of the concave portion of the front sheet and the joint of the lower sheet.

FIG. 15 is a partially enlarged plan view showing another example of the absorber forming the arrangement of the compressed portion of the high-density portion.

16 is an explanatory diagram of the effect of the present invention.

Hereinafter, the present invention will be described based on its preferred embodiments with reference to the drawings.

FIG. 1 shows a perspective view of a sanitary pad 10 (hereinafter, also simply referred to as "sanitary pad 10") as an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view taken along line II-II of FIG. 1.

As shown in FIGS. 1 and 2, the sanitary pad 10 includes a liquid-permeable front sheet 2 forming a skin contact surface, a liquid-impermeable back sheet 3, and the two sheets 2 interposed therebetween. 3间的absorbing body 4. Liquid impermeability includes liquid impermeability. The sanitary pad 10 has a vertically long shape, and has a longitudinal direction X and a width direction Y. The longitudinal direction X coincides with the front and back directions of the wearer when wearing the sanitary pad 10, and the width direction Y is a direction orthogonal to the longitudinal direction X when the sanitary pad 10 is viewed from above. The sanitary pad 10 has an elliptical shape in a plan view tapered at the center in the longitudinal direction.

The portions of the front sheet 2 and the back sheet 3 extending from the peripheral edge of the absorber 4 are joined to each other at the peripheral edge portion 7 of the sanitary pad 10. On the surface (non-skin-contacting surface) of the back pad 3 side of the sanitary pad 10, an adhesive portion (not shown) for fixing to underwear such as shorts is provided. The skin contact surface is the surface of the absorbent article or its constituent members that faces the wearer's skin when worn, and the non-skin contact surface is the opposite of the absorbent article or its constituent members that faces the wearer's skin when worn The side (usually the side of the underwear).

The absorbent body 4 of the sanitary pad 10 includes an absorbent sheet 42. More specifically, the absorbent sheet 42 includes a laminate in which two or more layers are stacked. A laminate with two or more layers may be a sheet in which an absorbent sheet is folded as shown in FIG. 3 and the layers are joined together to form a laminate, or a single sheet of absorbent sheet may be laminated to a plurality of sheets And those who are layering. In addition, it is also possible to arrange additional absorbent sheets between two or more layers of the laminate to form a single The part is a thick-walled absorber.

In the sanitary pad 10, as the absorbent sheet 42, an absorbent sheet containing a fiber material and a water-absorbing polymer is used. As the absorbent sheet, it is preferable to use the following, that is, the adhesive force generated by the water-absorbent polymer in a wet state, or an additional adhesive agent or adhesive agent such as adhesive fibers to make the inter-fiber or inter-composition The fiber and the water-absorbing polymer are combined to form a sheet. In addition, as the absorbent sheet, an absorbent sheet manufactured by the method described in Japanese Patent Laid-Open No. 8-246395 can also be used; after the pulverized pulp and water-absorbing polymer supplied with the air flow are accumulated ，Apply hot-melt adhesive to dry sheet, paper or non-woven fabric solidified by adhesive (such as vinyl acetate adhesive, PVA (polyvinyl alcohol) etc.), and then spread An absorbent sheet obtained from a super absorbent polymer; an absorbent sheet obtained by blending a super absorbent polymer in the manufacturing step of spunbond or meltblown nonwoven fabric, etc. These absorbent sheets may be used in the form of an absorbent body having a single-layer structure without being laminated in two or more layers. In addition, the layers may not be connected in the case of layering.

The thickness of the absorber 4 is preferably 0.1 mm or more, more preferably 0.5 mm or more, and more preferably 5 mm or less, more preferably 2 mm or less, and further preferably 0.1 mm or more and 5 mm or less, and more preferably 0.5 mm above 2mm. The thickness of the absorber 4 is measured by the following method.

The thickness T was measured using a micrometer with two parallel pressing surfaces (fixed pressing surface and movable pressing surface), that is, a PEACOCK-type precision measuring device (model R1-C). The measurement was carried out under the condition that the diameter of the movable pressing surface of the probe was 5 mm and the pressure was 100 kPa or less. The size of the test piece for measurement is set to be larger than the size of the following flat plate. Place a 20mm×20mm flat plate (mass 5.4g) on the test piece, operate the movable pressure surface of the probe at a speed of 2mm/s, and abut the flat plate to read the value immediately after stabilization. The pressure between the pressurized surfaces (pressure applied to the test piece) becomes 1.3 kPa or less.

As the forming material of the back sheet 3, it can be used without particular limitation for the previous absorption Various materials such as the back sheet of the sexual article, for example, a liquid-impermeable or water-repellent resin film, a laminated sheet of a resin film and a non-woven fabric, etc. can be used.

As shown in FIGS. 2 and 4, the front sheet 2 in the sanitary pad 10 of the present embodiment includes stripe-shaped convex stripe portions 13 and concave stripe portions 14 extending in one direction alternately arranged in the width direction The non-woven fabric 1 of the uneven structure. As shown in FIGS. 2 and 4, the front sheet 2 is joined to the adjacent lower sheet 6 at the joining portion 14 s at the concave strip portion 14 thereof, and the convex strip portion 13 is between the nonwoven fabric 1 and the lower sheet 6 Has a hollow structure. As shown in FIG. 6 below, 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. 4 shows a perspective view of the nonwoven fabric 1 (hereinafter also referred to as "nonwoven fabric 1") used as the front sheet 2 in the sanitary pad 10 of the present embodiment. FIG. 5 is a schematic view showing a cross section of the nonwoven fabric 1 shown in FIG. 4 in the thickness direction. FIG. 6 is an enlarged schematic view of the constituent fibers 11 of the non-woven fabric 1 shown in FIG. 4. As shown in FIG. 4, the non-woven fabric 1 is a non-woven fabric having plural fusion portions 12 (see FIG. 6) formed by thermally fusing the intersections of the constituent fibers 11. In addition, in the non-woven fabric 1, as shown in FIG. 4, the "one direction" in which the convex strip portion 13 and the concave strip portion 14 extend is the same direction as the longitudinal direction X of the sanitary pad 10, and is also expressed as a direction (X direction).

More specifically, as shown in FIG. 5, the non-woven fabric 1 has a plurality of convex strip parts 13 whose cross-sectional shapes of the front and back surfaces a and b are convex toward the upper direction of the thickness direction (Z direction); and concave The strip part 14 is located between the adjacent convex strip parts 13 and 13. The concave strip portion 14 is a concave shape in which the cross-sectional shapes of the front and back surfaces a and b are both upward toward the thickness direction (Z direction) of the nonwoven fabric. In other words, the cross-sectional shapes of both the front and back surfaces a and b of the concave strip portion 14 are convex toward the downward direction of the thickness direction (Z direction) of the nonwoven fabric. Moreover, the plurality of convex strip portions 13 continuously extend in one direction (X direction) of the nonwoven fabric 1, and the plurality of concave strip portions 14 also have a groove shape continuously extending in one direction X of the nonwoven fabric 1. The convex stripe portion 13 and the concave stripe portion 14 are parallel to each other, and are alternately arranged in a direction (Y direction) orthogonal to the above-mentioned one direction (X direction).

As shown in FIG. 5, when the non-woven fabric 1 is cross-sectionally viewed in the thickness direction Z, the non-woven fabric 1 includes a top region 13 a, a bottom region 13 b, and a side region 13 c located therebetween. The top region 13a, the bottom region 13b, and the side region 13c extend continuously in one direction (X direction) of the nonwoven fabric 1. When the nonwoven fabric 1 is cross-sectionally observed in the thickness direction Z, the top region 13a, the bottom region 13b, and the side region 13c divide the thickness of the nonwoven fabric 1 in the Z direction into three equal parts, and the portion above the thickness direction Z is set as the top region 13a, the central part is set as the side region 13c, and the lower part is set as the bottom region 13b. The top of the convex strip 13 is formed by the top region 13a. The bottom of the concave strip 14 is formed by the bottom region 13b.

As described below, the non-woven fabric 1 is manufactured by performing uneven processing on the fiber sheet 1a using one pair of uneven rollers 401 and 402 that mesh with each other. The longitudinal direction X of the non-woven fabric 1 refers to the same direction as the machine direction (MD, flow direction) when the non-woven fabric 1 is produced by performing uneven processing on the fiber sheet 1a (see FIG. 8), and is orthogonal to the X direction of the non-woven fabric 1 The direction Y refers to the same direction as the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction).

As shown in FIG. 5, when the nonwoven fabric 1 is viewed in the thickness direction Z, the fiber density of the side region 13c becomes lower than the fiber density of the top region 13a and the fiber density of the bottom region 13b. The fiber density refers to the number of fibers per unit area of the cross section of the non-woven fabric 1. Therefore, the number of fibers in the side region 13c is less than that in the top region 13a and the bottom region 13b (the distance between the fibers is large), and becomes a loose region. Therefore, the air permeability of the side region 13c is higher than that of the top region 13a and the bottom region 13b. As a result, when the sanitary pad of the present embodiment using the non-woven fabric 1 as the front sheet 2 is in its worn state, air flows along the concave strip portion 14 and in the convex strip portion 13, the air passes along the side region 13c It circulates in a direction orthogonal to the convex strip 13. In this way, the sanitary pad of the present embodiment has a structure in which air flows in either the longitudinal direction X and the width direction Y on the opposite side of the skin. Therefore, the air permeability on the opposite side of the skin is good, and the wearing state is unlikely to occur. It's sultry. And, by Since the convex stripe portions 13 and the concave stripe portions 14 including the non-woven fabric 1 are alternately formed, when the sanitary pad 10 is worn, the concave-convex structure of the front sheet 2 easily follows the action of the wearer, and the skin feels good.

In particular, as shown in FIG. 1, each side edge of the sanitary pad 10 is formed into a combined curve shape, and in the longitudinal front area 10A and rear area 10B, each side edge is convexly curved outward in the width direction, and In the central region 10C in the longitudinal direction, each side edge is convexly curved toward the inner side in the width direction, thereby narrowing the width in the central region 10C in the longitudinal direction to the narrowest, thereby easily and efficiently discharging toward the outer side in the width direction Y steam. Thereby, it is not easy to cause sultry when the sanitary pad 10 is worn.

Fiber density region 13c of the side portions (D _13c) with respect to the fiber density (D _13a) top region 13a of, or fiber density (D _13b) of the region 13b of the bottom of the ratio _{(D 13c / D 13a, D} 13c / D 13b) It is preferably 0.15 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less. Specifically, regarding the value of the fiber density of the nonwoven fabric 1, the fiber density (D _13a ) of the top region 13a is preferably 90 fibers/mm ² or more and 200 fibers/mm ² or less, and more preferably 100 fibers/mm ² or more And 180 pieces/mm ² or less. In addition, the fiber density (D _13b ) of the bottom region 13b is preferably 80 fibers/mm ² or more and 200 fibers/mm ² or less, and more preferably 90 fibers/mm ² or more and 180 fibers/mm ² or less. The fiber density (D _13a ) of the side region 13c is preferably 30 fibers/mm ² or more and 80 fibers/mm ² or less, and more preferably 40 fibers/mm ² or more and 70 fibers/mm ² or less. The measuring method of fiber density is as follows.

[Method of Measuring Fiber Density of Top Area 13a, Bottom Area 13b, and Side Area 13c]

The nonwoven fabric was cut in the thickness direction Z using a Feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.). Regarding the fiber density of the top region 13a, using a scanning electron microscope, the top region 13a, which is the upper part when the thickness of the cut surface of the nonwoven fabric is divided into three equal parts in the Z direction, is magnified and observed (adjusted to the fiber cross section to measure 30 ~~60 pieces of magnification, 150~500 times), count the number of cross-sections of the fiber cut by the cut surface per fixed area (about 0.5mm ² ). Next, it is converted into the number of fiber cross sections per 1 mm ² , and this is set as the fiber density of the top region 13a. The measurement was performed on three locations, and the average value was taken as the fiber density of the sample. Similarly, regarding the fiber density of the bottom region 13b, the lower part when the thickness of the cut surface of the nonwoven fabric is divided into three equal parts in the Z direction is measured and obtained. Similarly, regarding the fiber density of the side region 13c, the center portion when the thickness of the cut surface of the nonwoven fabric is divided into three equal parts in the Z direction is measured and obtained. In addition, as the scanning electron microscope, JCM-5100 (trade name) manufactured by JEOL Ltd. was used.

As described above, the fiber density (D _13c ) of the side region 13c of the convex strip portion 13 is preferably 30 pieces/mm ² or more and 80 pieces/mm ² or less, and more preferably 40 pieces/mm ² or more and 70 pieces /mm ² or less. That is, although the fiber density of the side region 13c is preferably lower than the fiber density of the top region 13a and the bottom region 13b, the fiber density of the side region 13c is preferably not zero. In other words, the fiber density of the side region 13c is preferably more than 0 fibers/mm ² . The fact that the fiber density of the side region 13c is zero means that a through hole is formed in the side region 13c. Therefore, in this embodiment, it is preferable that no through hole is formed in the side region 13c. When the fiber density of the side region 13c is zero, that is, when a through hole is formed in the side region 13c, liquid return is likely to occur through the through hole, or the convex strip 13 is easily crushed. If the number of through-holes formed is reduced so as not to cause such defects caused by the formation of the through-holes, the air circulation in the direction orthogonal to the convex strip 13 is reduced. In this way, there are various problems when forming the through hole in the side region 13c. On the other hand, if the fiber density of the side region 13c is reduced as in the present embodiment, there is a possibility of preventing backflow or flattening of the ridge portion 13, In addition, it has the advantage of ensuring the air circulation in the direction orthogonal to the convex strip portion 13.

The uneven structure of the nonwoven fabric 1 including the convex strip portion 13 and the concave strip portion 14 is preferably formed at least in the central region of the sanitary pad 10 in the width direction Y. In this way, the concave-convex structure can be provided in the part most likely to come into contact with the wearer's skin, so that the above-mentioned sultry prevention effect or the follow-up effect on the wearer's movement can be surely exerted. In particular, to make these effects more obvious In terms of surface, it is preferable that the front sheet 2 has a concave-convex structure in the entire region of the inner side of the peripheral edge portion 7 (see FIG. 1 ).

In the sanitary pad 10 of the present embodiment, preferably, at least in the central region 10C in the longitudinal direction, each side edge 4a of the absorber 4 is linear, and the extending direction of the side edge 4a is set to The above-mentioned uneven structure, that is, the extending direction of the convex stripe portion 13 and the concave stripe portion 14 is substantially parallel. Thereby, at the side edge 4a of the absorber 4, the front sheet 2 is easily bent, reducing the wearing discomfort of the sanitary pad 10. The so-called "substantially parallel" includes completely parallel cases and crosses within an angle of 3 degrees.

The constituent fibers 11 of the nonwoven fabric 1 include high-elongation fibers. Here, the high-elongation fiber included in the constituent fiber 11 means not only a fiber having a high elongation at the stage of the raw material fiber, but also a fiber having a high elongation at the stage of the manufactured nonwoven fabric 1. Examples of the "high-elongation fiber" include stretchable fibers that have elasticity (elastomers) and expand and contract. For example, Japanese Patent Laid-Open No. 2010-168715 paragraph [0033] describes melting at low speeds. After spinning to obtain a composite fiber, heat treatment and/or crimping treatment is performed without drawing treatment, thereby obtaining a heat-extensible fiber whose length is elongated by changing the crystal state of the resin by heating; Fibers made of resins such as propylene or polyethylene, with relatively low spinning speeds; or dry blended with polyethylene-polypropylene copolymer or polypropylene with low crystallinity for spinning Fiber made of silk. Among these fibers, the high-elongation fiber is preferably a core-sheath composite fiber having heat fusion properties. The core-sheath type composite fiber may be a concentric core-sheath type, an eccentric core-sheath type, a side-by-side type, or an abnormity type, especially a concentric core-sheath type. From the viewpoint of producing nonwoven fabrics that are soft and have good skin feel regardless of the form of the fiber, the fineness of the high-elongation fiber is preferably 1.0 dtex or more and 10.0 dtex or less at the raw material stage, more Preferably, it is 2.0dtex or more and 8.0dtex or less.

The constituent fibers 11 of the nonwoven fabric 1 may include other fibers in addition to the high-elongation fibers, but it is preferably composed of only the high-elongation fibers. As other fibers, for example Examples include non-heat-extensible core-sheath heat-fusible composite fibers that contain two components with different melting points and are processed by stretching, or fibers that are not originally heat-fusible (such as natural fibers such as cotton or pulp, and rayon) Or acetate, etc.). When the nonwoven fabric 1 includes high-elongation fibers and other fibers, the ratio of the high-elongation fibers in the nonwoven fabric 1 is preferably 50% by mass or more and 100% by mass or less, and more preferably 80% by mass Above and below 100% by mass.

The heat-extensible composite fiber as a high-elongation fiber is a composite fiber that has been subjected to unstretching treatment or weakly stretching treatment at the raw material stage, for example, it has a first resin component constituting the core and a second resin-containing polyethylene resin constituting the sheath The resin component, the first resin component has a higher melting point than the second resin component. The first resin component is a component expressing the thermal elongation of the fiber, and the second resin component is a component expressing thermal fusion. The melting points of the first resin component and the second resin component were measured using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Co., Ltd.) at a heating rate of 10° C./min to finely cut fiber samples (sample weight 2 mg) Thermal analysis is performed to determine the melting peak temperature of each resin, and the melting peak temperature is defined. When the melting point of the second resin component cannot be clearly determined by this method, the resin is defined as "a resin having no melting point". In this case, the temperature at which the molecules of the second resin component start to flow is set, and the temperature at which the second resin component is fused to the extent that the strength of the fusion point of the fiber can be measured is taken as the softening point, and this is used instead of the melting point.

As the second resin component constituting the sheath portion, a polyethylene resin is contained as described above. Examples of the polyethylene resin include low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE). In particular, high-density polyethylene having a density of 0.935 g/cm ³ or more and 0.965 g/cm ³ or less is preferable. The second resin component constituting the sheath portion is preferably a polyethylene resin alone, but other resins may be blended. Examples of other resins to be blended include polypropylene resins, ethylene-vinyl acetate copolymers (EVA), and ethylene-vinyl alcohol copolymers (EVOH). However, the second resin component constituting the sheath portion is preferably 50% by mass or more, particularly 70% by mass or more and 100% by mass or less of the resin component of the sheath portion is a polyethylene resin. In addition, the crystallite size of the polyethylene resin is preferably 10 nm or more and 20 nm or less, and more preferably 11.5 nm or more and 18 nm or less.

As the first resin component constituting the core portion, a resin component of polyethylene resin which is a constituent resin having a melting point higher than that of the sheath portion can be used without particular limitation. Examples of the resin component constituting the core include polyolefin resins such as polypropylene (PP) (excluding polyethylene resins), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). ) And other polyester resins. Furthermore, a polyamide-based polymer or a copolymer having two or more resin components can also be used. It can also be used by blending multiple resins. In this case, the melting point of the core is set to the melting point of the resin with the highest melting point. In terms of ease of manufacturing 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° C. or higher, and more preferably Below 150℃.

The preferred alignment index of the first resin component in the heat-extensible composite fiber that is a high-elongation fiber naturally differs depending on the resin used. For example, when the first resin component is a polypropylene resin, the alignment index is preferably 60% or less, more preferably 40% or less, and further preferably 25% or less. When the first resin component is polyester, the alignment index is preferably 25% or less, more preferably 20% or less, and still more preferably 10% or less. On the other hand, the alignment index of the second resin component is preferably 5% or more, more preferably 15% or more, and still more preferably 30% or more. The alignment index becomes an indicator of the degree of alignment of the polymer chain of the resin constituting the fiber. In addition, when the alignment indexes of the first resin component and the second resin component are respectively the above-mentioned values, the heat-extensible composite fiber is elongated by heating.

The alignment index of the first resin component and the second resin component is obtained by the method described in paragraphs [0027] to [0029] of Japanese Patent Laid-Open No. 2010-168715. In addition, the method for achieving the alignment index of each resin component in the heat-extensible composite fiber is described in paragraphs [0033] to [0036] of Japanese Patent Laid-Open No. 2010-168715.

In addition, the elongation of the high-elongation fiber in the raw material stage is preferably 100% or more, particularly preferably 200% or more, and particularly preferably 250% or more. Also, the elongation of high elongation fiber is The raw material stage is preferably 800% or less, particularly preferably 500% or less, and particularly preferably 400% or less. Specifically, the elongation of the high-elongation fiber in the raw material stage 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. By using a high-elongation fiber with an elongation in this range, the fiber is smoothly drawn in the stretching device. The change point from the small-diameter portion to the large-diameter portion described above is adjacent to the fusion portion and the skin touches The feeling becomes good.

The elongation of high-elongation fiber is based on JISL-1015, measured under the conditions of measuring the environmental temperature and humidity of 20±2℃, 65±2%RH, the interval of the clamp of the tensile testing machine is 20mm, and the stretching speed is 20mm/min. Benchmark. In addition, starting from the measurement of elongation by taking fibers from a nonwoven fabric that has been manufactured, when the distance between the clamps cannot be 20 mm, that is, the length of the measured fiber is less than 20 mm, the clamp interval is set to 10 mm or 5 mm. Perform the measurement.

The ratio of the first resin component to the second resin component (mass ratio, the former: the latter) in the heat-extensible composite fiber as a high-elongation fiber is preferably 10:90 to 90:10 in the raw material stage, and particularly preferably 20 : 80~80:20, especially 50:50~70:30. The fiber length of the heat-extensible composite fiber corresponds to the method of manufacturing the nonwoven fabric, and an appropriate length is used. When the nonwoven fabric is manufactured by the carding method as described below, for example, it is preferable to set the fiber length to about 30 to 70 mm.

The fiber diameter of the heat-extensible composite fiber as the high-elongation fiber is appropriately selected according to the specific application of the nonwoven fabric in the raw material stage. When a nonwoven fabric is used as a constituent member of an absorbent article such as a front sheet of an absorbent article, it is preferably 10 μm or more and 35 μm or less, especially 15 μm or more and 30 μm or less. The fiber diameter is measured by the following method.

[Determination of fiber diameter of fibers]

As the fiber diameter of the fiber, use a microscope VH-8000 (manufactured by Keyence) to enlarge the cross section of the fiber to 200 to 800 times to observe and measure the fiber Diameter (μm). The cross section of the fiber is obtained by cutting the fiber using a Feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.). Regarding one fiber extracted, the fiber diameter at the time of approximately a circle was measured at five locations, and the average value of 5 points of the measured values was taken as the fiber diameter.

In the raw material stage, as the heat-extensible composite fiber that is a high-elongation fiber, in addition to the above-mentioned heat-extensible composite fiber, Japanese Patent No. 4131852, Japanese Patent Laid-Open No. 2005-350836, and Japanese Patent Laid-Open 2007 can also be used. -303035, Japanese Patent Laid-Open No. 2007-204899, Japanese Patent Laid-Open No. 2007-204901, Japanese Patent Laid-Open No. 2007-204902 and other fibers described in fiber.

The non-woven fabric 1 is preferably, as shown in FIG. 6, when focusing on one of the constituent fibers 11 of the non-woven fabric 1, the constituent fiber 11 has a fiber diameter sandwiched between adjacent fusion portions 12 and 12 The smaller two small-diameter portions 16, 16 have a larger fiber diameter 17 than the larger fiber diameter. Specifically, as shown in FIG. 6, when focusing on one of the constituent fibers 11 of the nonwoven fabric 1, since the fusion portion 12 formed by thermally fusing the intersection with other constituent fibers 11, the fiber diameter is small The small-diameter portion 16 is formed with substantially the same fiber diameter extended. Furthermore, when focusing on the one constituent fiber 11, between the small-diameter portions 16, 16 extending from each of the adjacent fusion portions 12, 12, the fiber diameter is smaller than the diameter portion 16 and the large-diameter portion 17 is larger. It is formed with approximately the same fiber diameter. In detail, when focusing on one constituent fiber 11, the non-woven fabric 1 has a small diameter from the fusion part 12 of one of the adjacent fusion parts 12 and 12 toward the other fusion part 12, and a fusion part 12 side is sequentially arranged The constituent fibers 11 of the portion 16, one large-diameter portion 17, and the small-diameter portion 16 on the side of the other fusion portion 12 are.

As described above, by the presence of the small-diameter portion 16 of low rigidity adjacent to the fusion portion 12 where the rigidity of the nonwoven fabric 1 is increased, the softness of the nonwoven fabric 1 is improved and the skin feel is improved. In addition, the more the plurality of large-diameter portions 17 are provided, in other words, the more low-rigidity small-diameter portions 16 exist in the constituent fibers 11, the softer the non-woven fabric 1 is, the better the skin feel becomes.

As shown in FIG. 6, when focusing on one of the constituent fibers 11 of the non-woven fabric 1, the non-woven fabric 1 has a plurality of adjacent fusion portions 12, 12 (two of the non-woven fabric 1) The large-diameter portion 17 constitutes the fiber 11. In detail, when focusing on one constituent fiber 11, the non-woven fabric 1 has a small diameter from the fusion part 12 of one of the adjacent fusion parts 12 and 12 toward the other fusion part 12, and a fusion part 12 side is sequentially arranged The constituent fibers 11 of the portion 16, the first large-diameter portion 17, the small-diameter portion 16, the second large-diameter portion 17, and the small-diameter portion 16 on the other fusion portion 12 side. Regarding the non-woven fabric 1, when focusing on one constituent fiber 11, from the viewpoint of improving the skin touch and preventing the non-woven fabric from decreasing in strength, it is preferable to provide one or more between adjacent fusion parts 12, 12 In addition, from the viewpoint of improving the skin feel and reducing the strength of the nonwoven fabric, five or less large-diameter portions 17 are more preferably one or more and three or less.

The small-diameter portion 16 of the fiber diameter (L ₁₆₎ with respect to the large diameter portion 17 of the fiber diameter (L ₁₇₎ of the ratio (L ₁₆ / L ₁₇₎ is preferably 0.5 or more and 0.8 or less, and further preferably 0.55 or more And below 0.7. Specifically, from the viewpoint of improving skin feel, the fiber diameter (diameter L ₁₆ ) of the small-diameter portion 16 is preferably 5 μm or more and 28 μm or less, and more preferably 6.5 μm or more and 20 μm or less, particularly preferably 7.5 μm or more and 16μm or less. From the viewpoint of improving skin feel, the fiber diameter (diameter L ₁₇ ) of the large-diameter portion 17 is preferably 10 μm or more and 35 μm or less, more preferably 13 μm or more and 25 μm or less, and particularly preferably 15 μm or more and 20 μm or less.

The fiber diameters (diameters L ₁₆ and L ₁₇ ) of the small-diameter portion 16 and the large-diameter portion 17 are measured in the same manner as the measurement of the fiber diameter of the above fiber.

As shown in FIG. 6, regarding the non-woven fabric 1, when focusing on one of the constituent fibers 11 of the non-woven fabric 1, the point of change 18 from the small-diameter portion 16 adjacent to the fusion portion 12 to the large-diameter portion 17 Preferably, it is arranged within a range of 1/3 of the interval T between the fusion portion 12 and the adjacent fusion portions 12 and 12. Here, the change point 18 of the non-woven fabric 1 does not include the continuous gradual change from the small diameter portion 16 extending with a smaller fiber diameter to the large diameter portion 17 extending with a fiber diameter larger than the small diameter portion 16 Part or continuously changing over multiple stages Location, but refers to the location where the fiber diameter changes extremely in a period. In addition, in the case where the above-mentioned one constituent fiber 11 is a heat-extensible composite fiber, the change point 18 of the non-woven fabric 1 is not included between the first resin component constituting the core portion and the second resin component constituting the sheath portion The state where peeling occurs and the fiber diameter changes, but refers to the part where the fiber diameter always changes due to elongation.

In addition, the so-called change point 18 is arranged in the range of 1/3 of the interval T between the fusion part 12 and the adjacent fusion parts 12, 12 and the constituent fibers 11 of the nonwoven fabric 1 are randomly extracted and used as shown in FIG. 6 as Scanning electron microscope JCM-5100 (trade name) manufactured by Nippon Electronics Co., Ltd. is conducted on the constituent fibers 11 so that the adjacent fusion parts 12, 12 of the constituent fibers 11 can be observed (100 times to 300 times) Zoom in and observe. Then, the interval T between the centers of the adjacent fusion parts 12 and 12 is divided into three equal parts, and is divided into a region AT on the side of one fusion part 12, a region BT on the side of the other fusion part 12, and a central region CT. In addition, it means that the change point 18 is arranged in the above-mentioned area AT or the above-mentioned area BT. In addition, the change point 18 is arranged in the nonwoven fabric 1 within the range of 1/3 of the interval T between the fusion part 12 and the adjacent fusion parts 12, 12 when the constituent fibers 11 of 20 nonwoven fabrics 1 are randomly extracted. The constituent fibers 11 in which the change point 18 is arranged in the above-mentioned area AT or the above-mentioned area BT have at least one nonwoven fabric among 20 constituent fibers 11. Specifically, from the viewpoint of improving the feel of the skin, it is preferably 1 or more, more preferably 5 or more, and particularly preferably 10 or more.

The non-woven fabric 1 is formed such that the number of fibers having change points 18 among the constituent fibers 11 constituting the side region 13c is higher than the number of fibers having change points 18 among the constituent fibers 11 constituting the top region 13a, and the bottom region 13b Among the constituent fibers 11, there are many fibers with change points 18. The number of fibers (N _13c ) having a change point 18 in the constituent fibers 11 constituting the side region 13c relative to the number of fibers (N _13a ) having a change point 18 among the constituent fibers 11 constituting the top region 13a, or the configuration The ratio of the number of fibers (N _13b ) (N _13c /N _13a , N _13c /N _13b ) of the fibers 11 having the change point 18 in the constituent fibers 11 of the bottom region 13b is preferably 2 or more and 20 or less, and more preferably 5 Above and below 20. Specifically, regarding the specific value of the number of fibers having the change point 18 of the nonwoven fabric 1, the number of fibers (N _13c ) having the change point 18 among the constituent fibers 11 constituting the side region 13c is preferably 5 or more And 20 or less, and more preferably 10 or more and 20 or less. The number of fibers (N _13a ) having change points 18 among the constituent fibers 11 constituting the top region 13a is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less. In addition, the number of fibers (N _13b ) having change points 18 among the constituent fibers 11 constituting the bottom region 13b is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less. The method of measuring the number of fibers having a change point 18 is as follows.

[Method for measuring the number of fibers having a change point 18 among the constituent fibers constituting the top region 13a, the bottom region 13b, or the side region 13c]

Regarding the number of fibers having a change point 18 among the constituent fibers 11 constituting the top region 13a, a scanning electron microscope is used to enlarge the upper part when the thickness of the nonwoven fabric is divided into 3 equal parts in the Z direction, that is, near the vertex of the top region 13a Observe (adjusted to a fiber cross-section that can measure a magnification of about 30 to 60 fibers, 50 to 500 times), randomly extract 20 component fibers 11 that constitute the top region 13a, and change the number of fibers 18 that have a change point 18 in the 20 component fibers 11 Count. Let this be the number of fibers having a change point 18 among the constituent fibers constituting the top region 13a. The measurement was performed at three locations, and the average value was taken as the number of fibers having a change point 18 among the constituent fibers constituting the top region 13a of the sample. Similarly, regarding the number of fibers having a change point 18 among the constituent fibers 11 constituting the bottom region 13b, the lower part when the thickness of the nonwoven fabric is divided into 3 equal parts in the Z direction, that is, the vicinity of the bottom point of the bottom region 13b is measured And find out. Similarly, regarding the number of fibers having a change point 18 among the constituent fibers 11 constituting the side region 13c, the center portion when the thickness of the nonwoven fabric is divided into 3 equal parts in the Z direction is measured and obtained. In addition, as the scanning electron microscope, JCM-5100 (trade name) manufactured by JEOL Ltd. was used.

Regarding the thickness of the non-woven fabric 1, the thickness of the entire non-woven fabric 1 when viewed from the side is defined as the sheet thickness T _S , and the thickness of a portion of the non-woven fabric 1 whose irregularities are curved is defined as the layer thickness T _L. The sheet thickness T _S may be appropriately adjusted depending on the application. When used as a front sheet or sublayer of an absorbent article, it is preferably 0.5 mm or more and 7 mm or less, and more preferably 1.0 mm or more and 5 mm or less. By setting to this range, the absorption speed of body fluid during use is relatively fast, and the liquid return from the absorber can be suppressed, thereby achieving moderate cushioning. In addition, even if a load is applied, the shape of the convex strip 13 can be maintained.

The layer thickness _TL may also be different in each part of the non-woven fabric 1, and may be adjusted appropriately according to the application. The layer thickness T _{L1 of the} top region 13a is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.2 mm or more and 2.0 mm or less. The layer thickness T _{L2 of the} bottom region 13b is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.2 mm or more and 2.0 mm or less. The layer thickness T _{L3 of the} side region 13c is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.2 mm or more and 2.0 mm or less. By setting the relationship between the thicknesses of each layer _TL1 , _TL2 , and _TL3 to this range, the body fluid absorption speed during use is relatively fast, which can suppress the liquid return from the absorber, thereby achieving moderate cushioning.

The sheet thickness T _S and the layer thickness _TL are measured by the following method.

The measuring method of the sheet thickness T _S is measured using a thickness measuring device in a state where a load of 0.05 kPa is applied to the nonwoven fabric 1. The thickness gauge is a laser displacement meter manufactured by OMRON. Thickness measurement is to measure 10 points, and calculate the average of these to be the thickness.

The measurement method of the layer thickness _TL is to enlarge the cross section of the sheet by about 20 times by a digital microscope VHX-900 manufactured by KEYENCE, thereby measuring the thickness of each layer.

When the nonwoven fabric 1 is viewed from above, the distance between the tops of the convex strips 13 adjacent in the Y direction is preferably 1 mm or more and 15 mm or less, and more preferably 1.5 mm or more and 10 mm or less. The height H (see FIG. 4) of the convex strip part 13 is preferably 0.5 mm or more and 5 mm or less, and more preferably 1 mm or more and 3 mm or less. The height H is a cross section of the thickness direction Z of the nonwoven fabric 1 observed with a microscope, and measured under no load.

The basis weight of the nonwoven fabric 1 is preferably 15 g/m ² or more and 50 g/m ² or less, and more preferably 20 g/m ² or more and 40 g/m ² or less based on the average value of the whole.

On the surface of the constituent fibers 11 of the nonwoven fabric 1, a small amount of fiber treatment agents such as fiber colorants, antistatic properties agents, lubricants, hydrophilic agents, etc. may be attached at the raw material stage.

As a method for attaching the fiber treatment agent to the surface constituting the fiber 11, various known methods can be used without particular limitation. For example, application by spraying, application by a slit coater, application by transfer, dipping in a fiber treatment agent, etc. may be mentioned. These treatments can be performed on the fibers before meshing, or after meshing the fibers by various methods. However, the treatment must be performed before the hot air blowing treatment described below. The fiber with the fiber treatment agent attached to the surface is dried at a temperature (for example, 120° C. or lower) sufficiently lower than the melting point of the polyethylene resin by a hot air blow dryer.

As shown in FIGS. 2 and 4, the front sheet 2 in the sanitary pad 10 of the present embodiment is each of the concave strip portions 14 of the non-woven fabric 1 constituting the front sheet 2 by thermal fusion to the adjacent lower side The sheets 6 are joined. In this embodiment, the lower sheet 6 is the second sheet 6 that is an aggregate of fibers including thermoplastic resin and is disposed between the front sheet 2 and the absorber 4. As an aggregate of fibers of thermoplastic resin, a non-woven fabric is generally used.

The concave strip portion 14 of the front sheet 2 is continuously joined to the second sheet 6 in the longitudinal direction of the sanitary pad 10, and the joint portion 14s extends across the seal portions 7 at both ends in the longitudinal direction, and can The longitudinal direction X of the sanitary pad 10 is formed intermittently. By intermittently joining the front sheet 2 and the second sheet 6, the air permeability between the two sheets can be ensured, and the stuffiness of the sanitary pad 10 in the wearing state can be further reduced. However, the front sheet 2 and the second sheet 6 may be continuously joined over the entire area in the longitudinal direction X.

The joining of the front sheet 2 and the second sheet 6 is not limited to the above-mentioned heat fusion, and other joining methods such as joining using an adhesive such as a hot-melt adhesive may also be used. The length of the second sheet 6 in the longitudinal direction X and the width direction Y can be made shorter than that of the front sheet 2. Alternatively, the length of the second sheet 6 in the longitudinal direction X and the width direction Y may be the same as the front sheet 2.

By joining the front sheet 2 having a concave-convex structure and the flat second sheet 6, the concave-convex structure of the front sheet 2 becomes a structure in which the hollow structure of the convex strip portion 13 is not easily crushed even if a load is applied thereto. For example, it is preferable to apply a load of 4 g/cm ² to the sanitary pad 10 from the front sheet 2 side, the convex portion can maintain a hollow structure, and it is more preferable to apply a load of 20 g/cm ² In this state, the convex strip part can maintain the hollow structure. The so-called "sustainable hollow structure" means that after the load is applied, there is also a space inside the convex strip portion 13, allowing the shape of the space to be deformed before the load is applied. Whether or not there is a space inside the convex strip part 13 is confirmed by cutting the joined body of the front sheet and the second sheet 6 in the thickness direction Z to form a cross section, and observing the cross section with a microscope. The load of 4 g/cm ² assumes that the sanitary pad 10 is mounted on shorts, and the pressure applied to the sanitary pad 10 when wearing the shorts. The load of 20 g/cm ² is assumed to be the pressure applied to the sanitary pad 10 when the wearer sits on a chair while the sanitary pad 10 is worn.

When the constituent fiber of the nonwoven fabric 1 is a high-elongation fiber, it also helps the convex strip portion 13 not to be easily crushed against the load. In detail, in the manufacturing method of the nonwoven fabric 1 described below, when the fiber sheet 1a (refer to FIG. 8) is stretched to manufacture the nonwoven fabric 1, if the fiber is cut due to the extension, even if the convex portion 13 is formed, the The intensity of compression is also reduced. In this regard, by using high-elongation fibers, the fibers are less likely to be cut during the extension of the fiber sheet 1a, the above-mentioned low fiber density side regions 13c can be formed smoothly, and the ridges can be effectively prevented The intensity of 13 is reduced.

As the aggregate of the fibers of the thermoplastic resin constituting the second sheet 6, non-woven fabrics obtained by various production methods can be used. For example, it is possible to use a hot-air nonwoven fabric that uses the hot-air method to form the thermal fusion point of the fibers with the fiber web obtained by the carding method or the air spinning method, and uses the hot-roller method to form the heat between the fibers with the fiber web obtained by the carding method Various non-woven fabrics such as hot roll non-woven fabric, hot-embossed non-woven fabric, spunlace non-woven fabric, needle-punched non-woven fabric, resin bonded non-woven fabric, etc. at the fusion point.

In particular, as the nonwoven fabric, it is preferable to use a fluffy nonwoven fabric having an apparent density of 0.005 g/cm ³ or more and 0.5 g/cm ³ or less, particularly 0.01 g/cm ³ or more and 0.1 g/cm ³ or less. By using fluffy non-woven fabric as the second sheet 6, the second sheet 6 functions as a spacer that separates the absorber 4 and the front sheet 2, and promotes the circulation of air between the absorber 4 and the front sheet 2. Thereby, the stuffyness of the sanitary pad 10 in the wearing state is further prevented. As the fluffy nonwoven fabric, for example, hot air nonwoven fabric, air-spun nonwoven fabric, resin bonded nonwoven fabric, etc. can be preferably used.

In addition, at least the central region 10C in the longitudinal direction of the sanitary pad 10 makes the width of the absorber 4 narrower than any of the width of the front sheet 2 and the width of the second sheet 6, thereby making it easy to maintain the front sheet The dry state of the width of the material 2 and the portion of the left and right side portions of the second sheet 6 extending outward from the side edge 4a (see FIG. 2) of the absorber 4 in the width direction. As a result, even after the absorber 4 absorbs the liquid, the water vapor permeability of the left and right side portions of the sanitary pad 10 is not easily damaged. Therefore, the sultry heat in the wearing state is further reduced.

In the sanitary pad 10 of the present embodiment, the non-woven fabric 1 used as the front sheet 2 is preferably manufactured by a manufacturing method of the non-woven fabric including the following steps: a fusion step, which uses the fusion portion to include a high elongation The intersections of the constituent fibers of the fiber web of the fibers are thermally fused to form a fiber sheet; and an extension step is to extend the fiber sheet in one direction. With regard to one embodiment of the method for manufacturing the nonwoven fabric 1 used as the front sheet 2, the above-mentioned preferred method for manufacturing the nonwoven fabric 1 can be cited as an example, and the description will be made with reference to FIG. 8. FIG. 8 schematically shows a preferred manufacturing apparatus 100 used for the manufacturing method of the nonwoven fabric 1. The manufacturing apparatus 100 is preferably used for a manufacturer of hot air non-woven fabric. The manufacturing apparatus 100 includes a web forming section 200, a hot air treatment section 300, an extending section 400, and a lower sheet joining section 500 in order from the upstream side toward the downstream side in the manufacturing process.

As shown in FIG. 8, the net forming unit 200 includes a net forming device 201. As the net forming device 201, a carding machine is used. As the carding machine, it can be used without limitation in the same way as the general user in the technical field of absorbent articles. Instead of a carding machine, other net manufacturing devices, such as an air spinning device, can also be used.

As shown in FIG. 8, the hot air treatment unit 300 includes a cover 301. In the cover 301, hot air can be blown by hot air. In addition, the hot air treatment unit 300 has a ring shape including a breathable mesh 状的驱动带302. The conveyor belt 302 surrounds the cover 301. The conveyor belt 302 is formed of resin or metal such as polyethylene terephthalate.

The temperature of the hot air blown in the cover 301 and the heat treatment time are preferably adjusted in such a manner that the intersection of the high-elongation fibers contained in the constituent fibers 11 of the fiber web 1b is thermally fused. More specifically, the temperature of the hot air is preferably adjusted to a temperature higher than the melting point of the resin having the lowest melting point in the constituent fibers 11 of the fiber web 1b by 0°C to 30°C. The heat treatment time is preferably adjusted to 1 second to 5 seconds according to the temperature of the hot air. In addition, from the viewpoint of promoting further entanglement between the constituent fibers 11, the wind speed of the hot air is preferably about 0.3 m/sec to 1.5 m/sec. Moreover, the conveying speed is preferably about 5 m/min to 100 m/min.

As shown in FIGS. 8 and 9, the extending portion 400 includes a pair of uneven rollers 401 and 402 that can mesh with each other. The pair of concavo-convex rollers 401 and 402 are formed to be heatable, and are formed by alternately arranging large-diameter convex portions 403 and 404 and small-diameter concave portions (not shown) in the roller axis direction. The uneven rollers 401 and 402 may or may not be heated. Regarding the heating temperature when heating the uneven rollers 401 and 402, it is easy to extend the high-elongation fibers contained in the constituent fibers 11 of the following fiber sheet 1a It is preferably higher than the glass transition point of the resin with the highest glass transition point in the high-elongation fiber and below the melting point of the resin with the lowest melting point in the high-elongation fiber. More preferably, the temperature is higher than the glass transition point of the fiber by 10°C and lower than the melting point by 10°C, and further preferably the temperature is higher than the glass transition point of the fiber by 20°C and lower than the melting point by 20°C . For example, when using PET (core) with a glass transition point of 67°C and a melting point of 258°C/PE (sheath) with a glass transition point of -20°C and a melting point of 135°C as the fiber in the core/sheath structure, heating is performed, It is preferably heated to 67°C or higher and 135°C or lower, more preferably heated to 77°C or higher and 125°C or lower, and further preferably heated to 87°C or higher and 115°C or lower.

Further, as shown in FIG. 9, in the manufacturing apparatus 100, the interval (pitch) between the large-diameter convex portions 403 and 403 adjacent to each other in the roller axis direction of the uneven roller 401 is different from that in the roller axis direction of the uneven roller 402. The intervals (pitch) between adjacent large-diameter convex portions 404 and 404 are the same interval (between Distance) w, with regard to the interval (pitch) w, the high-elongation fibers contained in the constituent fibers 11 of the fiber sheet 1a are smoothly drawn in the stretching device, from the small-diameter portion to the large-diameter portion as described above From the viewpoint that the change point is adjacent to the fusion part and the skin feels good, it is preferably 1 mm or more and 10 mm or less, and particularly preferably 1.5 mm or more and 8 mm or less. From the same point of view, as shown in FIG. 9, the pressing amount t of the pair of uneven rollers 401 and 402 (the distance between the apex of the large-diameter convex portion 403 and the apex of the large-diameter convex portion 404 adjacent to each other in the roller axis direction) ) Is preferably 1 mm or more and 3 mm or less, and particularly preferably 1.2 mm or more and 2.5 mm or less. Furthermore, from the same viewpoint, the mechanical extension 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 portion 500 includes an uneven roller 402 and a smooth roller 501 having a smooth surface. Between the large-diameter convex portion 404 of the uneven roller 402 and the peripheral surface of the smooth roller 501, the uneven non-woven fabric 1 and the lower sheet 6 Join by heating and pressing.

The manufacturing method of the nonwoven fabric 1 using the manufacturing apparatus 100 having the above configuration will be described.

First, as shown in FIG. 8, in the web forming section 200, short fiber-like constituent fibers 11 having heat-extensible composite fibers as high-elongation fibers are used as raw materials, and the web forming device 201 as a carding machine The fiber web 1b is formed (web forming step). The fiber web 1b manufactured by the net forming device 201 is in a state where its constituent fibers 11 are sparsely intertwined with each other, and the shape retention as a sheet material is not obtained.

Next, as shown in FIG. 8, the fusion section 12 fuses the intersections of the constituent fibers 11 of the fiber web 1b containing high-elongation fibers to form a fiber sheet 1a (fusion step). Specifically, the fiber web 1b is transported on the conveyor belt 302, and the hot air treatment unit 300 is used to blow hot air in a hot air manner while passing through the cover 301. If the hot air is blown in this way, the constituent fibers 11 of the fiber web 1b are further entangled with each other, and at the same time, the intersection of the intertwined fibers is thermally fused (see FIG. 10(a)) to produce a sheet-shaped shape-retaining shape. Fiber sheet 1a.

Next, as shown in FIG. 8, the fused fiber sheet 1a is extended in one direction (stretching step). Specifically, the fused fiber sheet 1a having the shape retention property as a sheet is transported between a pair of uneven rollers 401, 402, as shown in FIGS. 10(a) to 10(c), and the fiber sheet The material 1a extends, and one constituent fiber 11 between adjacent fusion portions 12, 12 forms a large-diameter portion 17 with a large fiber diameter sandwiched between two small-diameter portions 16, 16 with a small fiber diameter, The change point 18 from the small-diameter portion 16 to the large-diameter portion 17 is formed in a range of 1/3 of the interval T between the fusion portion 12 and the adjacent fusion portions 12 and 12. As described in detail, the fiber sheet 1a that is thermally fused by the fusion section 12 at the intersection of the constituent fibers 11 shown in FIG. 10(a) is transported between the pair of uneven rollers 401, 402 to make the fiber sheet 1a It extends in an orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction). When the fiber sheet 1a extends in the orthogonal direction (CD, roll axis direction), the region between the fusion parts 12, 12 adjacent to each other, which constitutes the fixed constituent fibers 11 shown in FIG. 10(a), is orthogonal The direction (CD, roll axis direction) is actively stretched. In particular, as shown in FIG. 10(b), in the vicinity of each fusion portion 12 that fixes the constituent fibers 11, the local shrinkage is likely to occur first. With regard to one constituent fiber 11 between the adjacent fusion portions 12, 12, Two small-diameter portions 16, 16 are formed at both ends, and a portion sandwiched between the two small-diameter portions 16, 16 becomes a large-diameter portion 17, and a large-diameter portion 17 sandwiched between the two small-diameter portions 16, 16 is formed. In this way, in the vicinity of each fusion part 12, local shrinkage is likely to occur first, so the change point 18 from the small-diameter part 16 to the large-diameter part 17 is formed at the interval between the fusion part 12 and the adjacent fusion parts 12 and 12. Within 1/3 of T.

In addition, as for one of the constituent fibers 11 between a part of the adjacent fusion parts 12 and 12, as shown in FIG. 10( c ), in a state where there is room for extensible (room for extension), the cross-section is further orthogonal The direction (CD, roller axis direction) extends, and the large diameter portion 17 between the adjacent fusion portions 12 and 12 extends, and a plurality of small diameter portions 16 are formed in the large diameter portion 17.

In the stretching step, while forming the small-diameter portion 16 and the large-diameter portion 17 from high-elongation fibers, the fiber sheet 1a is located between the large-diameter convex portion 403 of the concavo-convex roller 401 and the large-diameter convex portion 404 of the concavo-convex roller 402. Some parts are longer than others. In this case, due to the fiber sheet The constituent fiber of 1a is a high-elongation fiber, so it will not be cut even if it is stretched, so that it is smoothly drawn. Since the portion of the fiber sheet 1a between the large-diameter convex portion 403 of the concavo-convex roller 401 and the large-diameter convex portion 404 of the concavo-convex roller 402 is the side region 13c of the convex strip portion 13 in the nonwoven fabric 1 targeted, By the above drawing, the fibers are not cut in the side region 13c, and the distance between the fibers is increased compared to before the extension. As a result, the fiber density of the side region 13c is lower than other parts, and the air permeability is improved. Furthermore, since the fibers constituting the side region 13c are not cut, the strength of the convex strip 13 is maintained at a high level. As a result, even if a load is applied to the convex strip portion 13, the convex strip portion 13 is not easily crushed.

The non-woven fabric 1 manufactured as described above is directly transferred to the sheet joining portion of the lower sheet joining portion 500 by the uneven roller 402 in a state of being deformed into an uneven shape. The sheet-shaped nonwoven fabric 6 for the second sheet material wound out from the roll-shaped winding 6'is supplied to the sheet confluence section, and the uneven-shaped nonwoven fabric 1 is in a state of overlapping with the belt-shaped nonwoven fabric 6 and is introduced into the unevenness Between the roller 402 and the smoothing roller 501. Between the concave-convex roller 402 and the smoothing roller 501, the concave portion of the uneven-shaped non-woven fabric 1 and the band-shaped non-woven fabric 6 are heated between the large-diameter convex portion 404 of the uneven-convex roller 402 and the peripheral surface of the smoothing roller 501 And pressurized and joined. In this way, a strip-shaped composite sheet 8 including the front sheet 2 including the nonwoven fabric 1 and the lower strip 6 is joined to the concave strip portion 14. The strip-shaped composite sheet 8 is introduced into the manufacturing line of the sanitary pad 10 after being wound up, or is introduced into the manufacturing line of the sanitary pad 10 without being wound up.

FIG. 11 shows a perspective view of an incontinence pad 10 (hereinafter, also simply referred to as "incontinence pad 10") as another embodiment of the present invention. FIG. 12(a) is an enlarged cross-sectional view taken along the line II-II of FIG. 11, and FIG. 12(b) is a view showing the back surface (the surface on the non-skin-contacting surface side) of the absorber of the incontinence pad 10 shown in FIG. In addition, with respect to the embodiments shown in FIGS. 11 to 16 described below, with respect to the aspects that are not particularly described, the descriptions in detail of the embodiments shown in FIGS. 1 to 10 are appropriately applied. In addition, in FIGS. 11 to 16, the same members as those shown in FIGS. 1 to 10 are denoted by the same symbols.

As shown in FIGS. 11 and 12(a), the incontinence pad 10 is provided with a liquid penetrating surface forming a skin contact surface Passive front sheet 2, liquid-impermeable back sheet 3, and absorber 4 interposed between these two sheets 2, 3. Liquid impermeability includes liquid impermeability. The incontinence pad 10 has a vertically long shape, and has a longitudinal direction X and a width direction Y. The longitudinal direction X is consistent with the front and back directions of the wearer when wearing the incontinence pad 10, and the width direction Y is a direction orthogonal to the longitudinal direction X when the incontinence pad 10 is viewed from above. The incontinence pad 10 has an elliptical shape in plan view.

The front sheet 2 and the back sheet 3 extend from the periphery of the absorber 4. An adhesive portion (not shown) for fixing to panties such as shorts is provided on the surface (non-skin-contacting surface) of the back sheet 3 side of the incontinence pad 10.

The absorbent body 4 of the incontinence pad 10 includes an absorbent core 40 and a chip-wrapped material 41 covering the absorbent core 40. The absorbent core 40 may include a fiber pile of liquid-absorbent fibers such as pulp, or a mixed fiber pile of the liquid-absorbent fibers and a water-absorbing 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. In addition to the cellulose-based hydrophilic fibers, polyolefin-based fibers such as polyethylene and polypropylene, and condensation-based fibers such as polyester and polyamide may be included. Examples of the water-absorbing polymer include sodium polyacrylate, (acrylic acid-vinyl alcohol) copolymer, sodium polyacrylate crosslinked body, (starch-acrylic acid) graft copolymer, (isobutylene-maleic anhydride) copolymer And its saponification, polyaspartic acid and so on. The fiber and the water-absorbent polymer can be used in combination of one kind or two or more kinds. As the core wrapping material 41, a water-permeable fiber sheet such as toilet paper or non-woven fabric is preferably used. In addition, the chip-wrapped material 41 may cover the entire absorbent core 40 with one sheet, or more than two pieces of chip-wrapped material, for example, may be covered with different sheets The skin contact surface side and the non-skin contact surface side of the absorbent core 40.

The thickness of the absorber 4 is preferably 1 mm or more, more preferably 2 mm or more, and more preferably 15 mm or less, more preferably 10 mm or less, and further preferably 1 mm or more and 15 mm or less, and further preferably 2 mm or more and 10 mm the following. The thickness of the absorber 4 is measured by the method described above.

Leak-proof cuffs 8 extending in the longitudinal direction are provided at the positions of both sides of the incontinence pad 10 on the skin-contacting surface side in the width direction Y, respectively. The leak-proof flanging 8 has a free end 8a and a fixed end 8b respectively extending in the longitudinal direction. The fixed end 8b is located on the front sheet 2. Furthermore, the leak-proof flange 8 is fixed to the front sheet 2 at the fixed end 8b. In addition, the fixed end 8b of the leak-proof flange 8 extends outward in the width direction Y, and the extended portion is joined to the extended portion in the width direction of the back sheet 3 to form the side flap 7. An elastic member 8c extending in the longitudinal direction X is attached to the free end 8a or its vicinity in the leak-proof flange 8 in an extended state. A plurality of elastic members 8c are arranged substantially parallel to each other. A portion where the plural elastic members 8c are mounted forms a planar elastic region 8d. The planar elastic region 8d has a specific length in the width direction Y, and extends in the length direction X at least at the position where the wearer's excretory portion is opposed. Moreover, the planar elastic region 8d can expand and contract in the longitudinal direction X. By contracting the elastic member 8c, the position between the free end 8a and the fixed end 8b of the leak-proof flanging 8 stands up in a substantially L shape toward the body side of the wearer, and the planar elastic region 8d abuts the wearer Skin, prevent side leakage of liquid.

As shown in FIGS. 12(a) and 13, the front sheet 2 in the incontinence pad 10 of the present embodiment includes stripe-shaped convex stripe portions 13 and concave stripe portions 14 extending in the longitudinal direction alternately arranged in the width direction The non-woven fabric 1 of the uneven structure. Also, as shown in FIGS. 12(a) and 13, the front sheet 2 is joined to the adjacent second sheet 6 (lower sheet) at the joining portion 14s at the concave portion 14 thereof, and the convex portion 13 is joined to the There is a hollow structure between the second sheets 6. As shown in FIG. 6 described above, 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. 13 shows a perspective view of the nonwoven fabric 1 used as the front sheet 2 in the incontinence pad 10 of the present embodiment. As shown in FIG. 13, the non-woven fabric 1 includes a plurality of non-woven fabrics having fusion portions 12 (see FIG. 6) formed by thermally fusing the intersections of the constituent fibers 11. In addition, in the nonwoven fabric 1 constituting the front sheet 2, as shown in FIG. 13, the convex stripe portion 13 and the concave stripe portion 14 extend The "one direction" is the same direction as the longitudinal direction X of the incontinence pad 10, and the "one direction" in which the convex strip portion 13 and the concave strip portion 14 of the nonwoven fabric 1 extend is also expressed as the X direction.

More specifically, as shown in FIG. 5 described above, the non-woven fabric 1 has a plurality of convex strip parts 13 whose cross-sectional shapes of the front and back surfaces a and b are convex upward in the thickness direction (Z direction) Shape; and concave strip portion 14, which is located between adjacent convex strip portions 13, 13 each other. The concave strip portion 14 is a concave shape in which the cross-sectional shapes of the front and back surfaces a and b are both upward toward the thickness direction (Z direction) of the nonwoven fabric. In other words, the cross-sectional shapes of both the front and back surfaces a and b of the concave strip portion 14 are convex toward the downward direction of the thickness direction (Z direction) of the nonwoven fabric. Moreover, the plurality of convex strip portions 13 continuously extend in one direction (X direction) of the nonwoven fabric 1, and the plurality of concave strip portions 14 also have a groove shape continuously extending in one direction X of the nonwoven fabric 1. The convex stripe portion 13 and the concave stripe portion 14 are parallel to each other, and are alternately arranged in a direction (Y direction) orthogonal to the one direction (X direction).

The uneven structure of the non-woven fabric 1 including the convex strip portion 13 and the concave strip portion 14 is preferably formed at least in the central region of the incontinence pad 10 in the width direction Y. In this way, the concave-convex structure can be provided in the part most likely to come into contact with the wearer's skin, so that the above-mentioned anti-sticky effect can be more surely exerted.

The constituent fibers 11 of the nonwoven fabric 1 include high-elongation fibers. In addition, the constituent fibers 11 of the nonwoven fabric 1 may include other fibers in addition to the high-elongation fibers, and it is preferably composed of only the high-elongation fibers. Examples of high-elongation fibers and other fibers are as described above.

As shown in FIG. 3 described above, the top of the non-woven fabric 1 is formed by the top region 13 a of the convex strip part 13, and the bottom of the concave strip part 14 is formed by the bottom region 13 b. Therefore, the rib portions 13 of the nonwoven fabric 1 constituting the front sheet 2 have side regions 13c on both sides of the top region 13a, respectively, and a fiber density is formed between the top region 13a and the joint 14s. 13a is the lower side region 13c. Since the fiber density of the side region 13c is lower than that of the top region 13a, or the top region 13a and the bottom region 13b, the liquid entering between the convex strip parts 13c The body is transferred to the hollow space under the convex strip 13 or the second sheet 6 through the side area 13c, and the transferred liquid is not easily returned to the top area 13a forming the surface contacting the skin. In this way, the unpleasantness caused by the contact of the excretory fluid with the wearer's skin can be more reliably prevented.

The nonwoven fabric 1 is formed such that the number of fibers having change points among the constituent fibers constituting the side region 13c is higher than the number of fibers having change points 18 among the constituent fibers constituting the top region 13a, and the constituent fibers constituting the bottom region 13b The number of fibers with a change point of 18 is large. The number of fibers having change points (N _13c ) among the constituent fibers constituting the side region 13c relative to the number of fibers (N _13a ) having change points 18 among the constituent fibers constituting the top region 13a, or the bottom region 13b The ratio of the number of fibers (N _13b ) (N _13c /N _13a , N _13c /N _13b ) having a change point 18 among the constituent fibers is preferably 2 or more and 20 or less, and more preferably 5 or more and 20 or less . Specifically, regarding the specific value of the number of fibers having a change point 18 of the nonwoven fabric 1, the number of fibers having a change point 18 (N _13a ) among the constituent fibers constituting the top region 13a is preferably 1 or more and 15 Roots or less, and more preferably 5 or more and 15 or less. The number of fibers (N _13b ) having a change point 18 among the constituent fibers constituting the bottom region 13b is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less. The number of fibers (N _13c ) having a change point 18 among the constituent fibers constituting the side region 13c is preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less. The method of measuring the number of fibers having a change point 18 is as follows.

As shown in FIGS. 12 and 13, the front sheet 2 in the incontinence pad 10 of the present embodiment is formed by the heat fused and adjacent to each of the concave strips 14 of the non-woven fabric 1 constituting the front sheet 2. The second sheets 6 of the side sheets are joined. In this embodiment, the lower side sheet is the second sheet 6 which is an aggregate of fibers containing thermoplastic resin and is disposed between the front sheet 2 and the absorber 4. As an aggregate of fibers of thermoplastic resin, a non-woven fabric is generally used.

As shown in FIG. 13, the concave strip portion 14 of the front sheet 2 and the nonwoven fabric 1 containing fibers of thermoplastic resin are continuously joined to the second sheet 6 along the length of the incontinence pad 10. The lengthwise portion of the portion where the material 2 and the second sheet 6 overlap. Such as As shown in FIG. 14, by continuously joining the concave strip portion 14 of the front sheet 2 and the second sheet 6, the liquid transferred onto the second sheet 6 under the convex strip portion 13 can be prevented from projecting to the side convex strip The portion 13 is transferred downward, and the above-mentioned liquid is efficiently diffused in the longitudinal direction X. Therefore, it is possible to more reliably suppress the unpleasant sensation caused by the contact of the excretory fluid with the wearer's skin, and to utilize the absorption capacity of the absorbent body 4 in a wider range in the longitudinal direction more effectively. However, the front sheet 2 and the second sheet 6 may be formed intermittently in the longitudinal direction X.

In the incontinence pad 10, the front sheet 2 and the second sheet 6, more specifically, the non-woven fabric 1 constituting the front sheet 2 and the aggregate of the fibers constituting the second sheet 6 respectively include fibers of a thermoplastic resin. In the above-mentioned joining portion 14s, the concave strip portion 14 of the front sheet 2 and the second sheet 6 are integrally heated and pressurized by heat sealing to perform thermal fusion.

In the bonding portion 14s by thermal fusion, it is preferable that the constituent fibers of the nonwoven fabric 1 constituting the front sheet 2 and the constituent fibers of the assembly of fibers constituting the second sheet 6 do not maintain the form of the fibers. In order not to maintain the shape of the fiber, it is preferable to set the heating temperature of the heat seal to the melting point of the constituent fibers of one or both of the nonwoven fabric and the fiber assembly. In the case of composite fibers containing two components with different melting points and different temperatures, the melting point of the constituent fibers is set to the melting point of the component with the lowest melting point.

With the configuration of the joint portion 14s, the liquid transferred to the second sheet 6 under the convex strip portion 13 can be prevented from transferring to the downward convex strip portion 13 and the liquid can be efficiently diffused in the longitudinal direction X. Therefore, it is possible to more reliably suppress the unpleasant sensation caused by the contact of the excretory fluid with the wearer's skin, and to utilize the absorption capacity of the absorbent body 4 in a wider range in the longitudinal direction more effectively.

In addition, it is preferable that the joining portion 14s of the concave strip portion 14 and the second sheet 6 (lower sheet) is liquid-impermeable. Here, the liquid impermeability means that the liquid does not pass through the front sheet 2 or the second sheet 6.

As a method of forming the liquid-impermeable joint 14s, there may be mentioned a method in which the front sheet 2 and the second sheet 6 are thermally fused in such a manner that the constituent fibers of the two do not maintain the form of the fibers Law etc.

Instead of joining the front sheet 2 and the lower sheet such as the second sheet 6 by heat fusion, other joining methods such as joining with an adhesive such as a hot-melt adhesive and the second sheet 6 ( Lower sheet) joined.

The joining of the front sheet 2 and the second sheet 6 is not limited to the above-mentioned heat fusion, and other joining methods such as joining using an adhesive such as a hot-melt adhesive may also be used. The second sheet 6 can make the length in the longitudinal direction X and the width direction Y shorter than the front sheet 2. Alternatively, the length of the second sheet 6 in the longitudinal direction X and the width direction Y may be the same as the front sheet 2.

As the non-woven fabric constituting the second sheet 6, a long-fiber non-woven fabric in which fibers are aligned in the longitudinal direction X is preferable. The long-fiber non-woven fabric refers to a non-woven fabric including long fibers, and examples thereof include spun-bonded non-woven fabric and spunlace non-woven fabric.

In addition, as the nonwoven fabric constituting the second sheet 6, nonwoven fabrics other than long fiber nonwoven fabrics can be used. For example, various nonwoven fabrics such as hot roll nonwoven fabrics, hot embossed nonwoven fabrics, spunlace nonwoven fabrics, etc., which constitute fibers aligned in the longitudinal direction X, can also be used. . Regarding these nonwoven fabrics, whether or not the constituent fibers are aligned in the longitudinal direction X can be determined by the following method.

The degree of fiber alignment is measured in the form of MOR (modulus of rupture) value by microwave molecular alignment meter MOA-6004 (manufactured by Oji Scientific Instruments). The degree of fiber alignment is the average of 5 points of the sample.

By aligning the constituent fibers of the second sheet 6 along the longitudinal direction X, the liquid transferred to the hollow space under the convex strip part 13 or the liquid of the second sheet 6 does not transfer to the convex strip part under the convex strip part 13 13 times, and easy to spread along the length direction, less likely to produce side leakage or sticky feeling.

In the incontinence pad 10 of the present embodiment, the fiber density of the aggregate of fibers constituting the second sheet 6 is higher than the fiber density of the nonwoven fabric 1 constituting the front sheet 2.

When the nonwoven fabric 1 used in the present embodiment has a plurality of regions with different fiber densities in the thickness direction, the fiber density (D _13a ) of the nonwoven fabric constituting the front sheet 2 is set as the fiber density at the top of the convex strip 13 . In addition, the fiber density (D ₆ ) of the aggregate of the fibers constituting the second sheet 6 is set to the fiber density of the non-joint portion 6 a that is not joined to the nonwoven fabric constituting the front sheet 2.

The fiber density (D _13a ) at the top of the ridge portion 13 is measured in the same manner as the fiber density at the top region 13a. The fiber density (D ₆ ) of the assembly of fibers constituting the second sheet 6 is to use the Feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.) to align the assembly of fibers constituting the second sheet 6 Cut in the thickness direction Z, and observe the cut surface of the non-joined part of the fiber assembly in an enlarged manner, in addition to the fiber density of the above [top region 13a, bottom region 13b, and side region 13c Measurement method] Measure in the same way. The fiber density of the non-joining portion 6a of the second sheet 6 is preferably measured by observing the cut surface of the portion of the second sheet 6 facing the top (top area 13a) of the convex strip portion 13.

The second sheet material fiber density (D _{6) 6} with respect to the top (top region 13a) of the protruding strip portion of the fiber density (D _13a) of the ratio (D ₆ / D _13a) is preferably 1.1 or more, and further preferably 2 or more.

In the absorber 4 of the incontinence pad 10 of the present embodiment, as shown in FIGS. 12(a) and 12(b), high-density portions are formed in a plurality of positions in the width direction Y by embossing 43. The density of the high-density portion 43 is higher than that of the portions 44 and 44 (hereinafter also referred to as low-density portions 44) located on both sides in the width direction, and is formed to extend in the longitudinal direction X, respectively. That is, in the absorber 4, the high-density portions 43 and the low-density portions 44 are alternately arranged side by side.

Further, as shown in FIG. 12( a ), each of the high-density portions 43 is formed at a position overlapping the top of the convex strip portion 13. As described in detail, the high-density portion 43 extends in the longitudinal direction X and forms a plurality of rows in the width direction Y. Each of the high-density portions 43 continuously overlaps the top of the convex strip portion 13 in the longitudinal direction X.

The high-density portion 43 in this embodiment is formed by applying pressure between an embossing roller having a convex portion and a groove portion extending alternately in the circumferential direction or axial direction on the circumferential surface and an anvil roller having a smooth surface, and forming In the high-density part 43, the thickness of the absorber 4 becomes thinner than other parts. In addition, the surface of the absorber 4 on the non-skin-contacting surface side is the surface on the embossing roller side, and the high-density portion 43 absorbs The surface of the body 4 on the non-skin-contacting surface side has a concave portion corresponding to the convex portion of the peripheral surface of the embossing roller.

The high-density portion 43 may be formed only by pressing, or may be formed by heating while pressing.

The number of high-density portions 43 formed along the width direction Y of the absorber 4 and overlapping the top of the convex strip portion 13 of the front sheet 2 is plural, preferably 3 or more, more preferably 5 or more, and It is preferably 8 or more.

The length of the high-density portion 43 in the width direction Y is preferably 20 mm or more, and more preferably 50 mm or more. The length of the high-density portion 43 continuous in the longitudinal direction X is preferably 30% or more, more preferably 50% or more, and more preferably 100% with respect to the total length of the absorber 4 in the same direction.

In addition, the high-density portion 43 may be a high-density portion 43 that is long in the longitudinal direction X and is continuously formed along the longitudinal direction X of the absorber 4 or may be formed in the longitudinal direction X as shown in FIG. 15 The long-shaped high-density portion 43 is formed intermittently along the longitudinal direction X of the absorber 4. In this case, the length L3 of the high-density portion 43 in the longitudinal direction X is preferably 0.5 mm or more, and more preferably 1 mm or more, and the length L3 of the high-density portion 43 is the length L3 and the longitudinal direction X The total length L5 of the lengths of the adjacent high-density portions 43 and 43 is preferably 5% or more, and more preferably 30% or more.

The ratio (D ₃ /D ₄ ) of the density (D ₃ ) of the density (D ₃ ) of the density (D ₄ ) of the low-density portion 44 is preferably 1.5 or more, and more preferably 3 or more. The density of the high-density portion 43 and the low-density portion 44 is to use a Feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.), and cut out fine samples over the entire thickness direction from each part of the absorber 4, The mass of each sample is measured, and the measured mass is divided by the volume calculated by multiplying the thickness of the sample by the area in plan view. The thickness of the sample is measured under no load before cutting out from the absorber.

According to the incontinence pad 10 of the present embodiment, the front sheet 2 includes the nonwoven fabric 1 having the uneven structure of the convex strip portion 13 and the concave strip portion 14 extending in the longitudinal direction X, and constitutes the second The fiber density of the fiber assembly of the sheet 6 is higher than the fiber density of the non-woven fabric 1. Therefore, when the liquid A such as urine is supplied to the skin contact surface side, the liquid A quickly enters the convex portion 13 as shown in FIG. 16 Between each other, and from the both side portions of the top of the protruding strip portion 13, especially the above-mentioned side region 13c, is transferred to the second sheet 6 under the protruding strip portion 13.

Moreover, regarding the liquid B transferred to or in the second sheet 6 under the convex stripe portion 13, there is a density difference between the nonwoven fabric 1 and the second sheet 6, and the concave stripe portion 14 is joined to the second sheet 6 It is easy to maintain the hollow structure of the convex strip 13 during wearing, so the liquid B is not easy to return to the skin-contacting part of the convex strip 13. With this, the unpleasantness caused by the contact of the excretory fluid with the wearer's skin can be more surely suppressed.

From the viewpoint of exerting this effect, it is preferable that the second sheet 6 (lower sheet) has higher hydrophilicity than the front sheet 2. The hydrophilicity of the second sheet 6 and the hydrophilicity of the front sheet 2 are measured by the contact angle of water to the fibers constituting the second sheet 6 and the contact angle of water to the constituent fibers of the nonwoven fabric 1 constituting the front sheet 2 to determine The smaller the contact angle, the lower the hydrophilicity.

In addition, according to the incontinence pad 10 of the present embodiment, the portion of the absorber 4 that overlaps with the top (top region 13a) of the convex strip portion 13 of the nonwoven fabric 1 has the high-density portion 43, so it is transferred to the area under the convex strip portion 13 The liquid B on the second sheet 6 flows along the longitudinal direction X on the low-density portion 44 and is absorbed by the high-density portion 43.

Thereby, the unpleasant sensation caused by the contact of the excretory fluid with the wearer's skin can be reliably suppressed, and the absorption capacity of the wider range of the absorbent body 4 in the longitudinal direction can be effectively utilized.

Preferably, the second sheet 6 and the absorber 4, the layers of the absorbent sheet constituting the absorber 4, and the absorber 4 and the back sheet 3 are each joined by an adhesive. In the case where the members are joined by an adhesive, full coating using a slit coater or the like may also be used, preferably pattern coating. Preferred examples of the coating pattern for pattern coating include spiral patterns, dot patterns, stripe patterns (stripe patterns), grid patterns, and checkerboard patterns.

In the above, the present invention has been described based on its preferred embodiments, but the present invention The absorbent article is not subject to any limitation of the present embodiment described above, and can be appropriately changed. For example, the above embodiment is an example in which the present invention is applied to a sanitary pad or an incontinence pad. Alternatively, the present invention may be applied to other absorbent articles, such as menstrual sanitary napkins or disposable diapers.

In addition, in the embodiment shown in FIG. 11, the length of the second sheet 6 including the nonwoven fabric in one or both of the longitudinal direction X and the width direction Y of the incontinence pad 10 may be the same as that of the front sheet 2, It can also be shorter. In addition, the incontinence pad 10 may be a person who does not have a leak-proof flanging.

Regarding the above embodiment, the present invention further discloses the following absorbent articles.

<1>

An absorbent article comprising a liquid-permeable front sheet, a back sheet, and an absorber interposed between these two sheets, which has a longitudinal direction and a width direction. The sheet material includes a non-woven fabric with a concave-convex structure in which stripe-shaped convex stripe portions and concave stripe portions extending in the longitudinal direction are alternately arranged in the width direction, and is joined to the adjacent lower sheet at the concave stripe portion. If at least high-elongation fiber is used as the raw material, the lower sheet contains an aggregate of fibers of a thermoplastic resin, the convex portion has a hollow structure between the nonwoven fabric and the lower sheet, and the nonwoven fabric has a top region and a bottom Region, and a side region between them, the top of the convex strip part is formed by the top region, the bottom of the concave strip part is formed by the bottom region, the fiber density of the side region is higher than that of the fiber of the top region Either the density or the fiber density in the bottom region is low.

<2>

The absorbent article according to the above <1>, wherein the central region in the width direction of the absorbent article has at least the uneven structure.

<3>

The absorbent article as described in the above <1> or <2>, wherein the convex strip part can maintain a hollow structure in a state where a load of 4 g/cm ² is applied to the absorbent article from the front sheet side.

<4>

The absorbent article according to any one of the above <1> to <3>, wherein the joining of the front sheet and the lower sheet is intermittently performed in the direction in which the convex stripe extends.

<5>

The absorbent article according to any one of the above <1> to <4>, wherein the width of the absorber is at least at the center region in the longitudinal direction of the absorbent article compared to the width of the front sheet and the lower side sheet Either the width of the material is narrow, and in the central region of at least the longitudinal direction of the absorbent article, each side edge of the absorbent body is linear, and is approximately in the direction in which the convex stripe and the concave stripe extend parallel.

<6>

The absorbent article as described in any one of <1> to <4> above, wherein each side edge of the absorbent article is in the shape of a combined curve, and the absorbent article has a front area and a rear area in its longitudinal direction, Each side edge is convexly curved toward the outer side in the width direction, and in the central region in the longitudinal direction, each side edge is convexly curved toward the inner side in the width direction, whereby the width of the central region in the longitudinal direction becomes the narrowest.

<7>

The absorbent article according to any one of the above <1> to <6>, wherein the front sheet and the back sheet are joined at the peripheral edge of the absorbent article, and the front sheet is positioned more than the peripheral edge The entire area of the inner part of the part has the above-mentioned uneven structure.

<8>

The absorbent article as described in any one of <1> to <7> above, wherein the convex strip portion can be maintained in a state where a load of 20 g/cm ² is applied from the front sheet side to the absorbent article Its hollow structure.

<9>

The absorbent article as described in any one of <1> to <8> above, wherein the absorbent body includes an absorbent sheet containing a fiber material and a water-absorbing polymer.

<10>

The absorbent article according to the above <9>, wherein the absorbent body includes a laminate in which the absorbent sheet is laminated with two or more layers.

<11>

The absorbent article as described in any one of <1> to <10> above, wherein the thickness of the absorbent body is preferably 0.1 mm or more, more preferably 0.5 mm or more, and further preferably 5 mm or less, more preferably 2 mm or less, and preferably 0.1 mm or more and 5 mm or less, and more preferably 0.5 mm or more and 2 mm or less.

<12>

The absorbent article as described in any one of the above <1> to <11>, wherein the lower sheet contains an apparent density of 0.005 g/cm ³ or more and 0.5 g/cm ³ or less, especially 0.01 g/cm ³ or more ³ or less of the fluffy and 0.1g / cm nonwoven.

<13>

The absorbent article as described in any one of <1> to <12> above, wherein the nonwoven fabric includes fibers having large and small diameter portions having different fiber diameters.

<14>

The absorbent article as described in any one of <1> to <13> above, wherein the nonwoven fabric includes a plurality of fusion portions formed by thermally fusing intersections of constituent fibers.

<15>

The absorbent article according to any one of the above <1> to <14>, wherein the fiber density D _13c of the side region is relative to the fiber density D _{13a of} the top region, or the fiber density D _{13b of} the bottom region The ratio (D _13c /D _13a , D _13c /D _13b ) is preferably 0.15 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less.

<16>

As described above <1> to the absorbent article <15> according to any one of, wherein said top region of the fiber density D _13a is preferably 90 / mm ² or more and 200 / mm ² or less, and further preferably 100 pieces/mm ² or more and 180 pieces/mm ² or less.

<17>

As described above <1> of the absorbent article to <16> according to any one of, wherein the fiber density of the bottom of the area D _13b is preferably 80 / mm ² or more and 200 / mm ² or less, and further preferably 90 pieces/mm ² or more and 180 pieces/mm ² or less.

<18>

As described above <1> to <17> The absorbent article according to any of one of claims, wherein the fiber density of the side area 30 is preferably D _13c / ² or more and 80 mm / mm ² or less, and further preferably 40 pieces/mm ² or more and 70 pieces/mm ² or less.

<19>

The absorbent article as described in any one of <1> to <18> above, wherein the high-elongation fiber is a core-sheath composite fiber having heat fusion properties.

<20>

The absorbent article as described in any one of the above <1> to <19>, wherein the fineness of the high-elongation fiber is preferably 1.0 dtex or more and 10.0 dtex or less in the raw material stage, more preferably 2.0 dtex or more and 8.0 Below dtex.

<21>

The absorbent article as described in any one of <1> to <20> above, wherein the above The ratio of the high-elongation fiber in the nonwoven fabric is preferably 50% by mass or more and 100% by mass or less, and more preferably 80% by mass or more and 100% by mass or less.

<22>

The absorbent article as described in any one of <1> to <21> above, wherein when focusing on one of the constituent fibers of the nonwoven fabric, the constituent fibers have a sandwich between adjacent fusion parts The large-diameter part with the larger fiber diameter in the two small-diameter parts with the smaller fiber diameter.

<23>

The absorbent article according to the above <22>, wherein when focusing on one of the constituent fibers, a plurality of the large-diameter portions are provided between the adjacent fusion-bonding portions.

<24>

The absorbent article as described in the above <22> or <23>, wherein focusing on one of the above-mentioned constituent fibers, it is preferable to provide one or more and five or less of the above between the adjacent fusion parts It is more preferable to provide one or more and three or less large diameter parts.

<25>

As the above <22> to <24> The absorbent article according to any one of claims of which the small diameter portion 16 of the fiber diameter (L ₁₆₎ with respect to the large-diameter portion of the fiber diameter (L ₁₇₎ of the ratio ( L ₁₆ /L ₁₇ ) is preferably 0.5 or more and 0.8 or less, and more preferably 0.55 or more and 0.7 or less.

<26>

The absorbent article as described in any one of <22> to <25> above, wherein the fiber diameter (diameter L ₁₆ ) of the small-diameter portion is preferably 5 μm or more and 28 μm or less, and more preferably 6.5 μm or more and 20 μm or less, particularly preferably 7.5 μm or more and 16 μm or less.

<27>

The absorbent article according to any one of the above <22> to <26>, wherein the fiber diameter (diameter L ₁₇ ) of the large diameter portion is preferably 10 μm or more and 35 μm or less, and more preferably 13 μm or more and 25 μm Below, particularly preferably 15 μm or more and 20 μm or less.

<28>

The absorbent article as described in any one of <22> to <27> above, wherein when focusing on one of the constituent fibers, the point of change from the small diameter portion adjacent to the fusion portion to the large diameter portion is It is arranged within a range of 1/3 of the interval T between the fusion part and the adjacent fusion parts.

<29>

The absorbent article as described in any one of the above <1> to <28>, wherein the nonwoven fabric includes fibers having large and small diameter portions having different fiber diameters, and the nonwoven fabric is formed to constitute the side The number of fibers having a change point from the small diameter portion adjacent to the fusion portion to the large diameter portion of the constituent fibers in the partial area is higher than that of the fibers having the change point in the constituent fibers constituting the top area The number of fibers and the number of fibers having the above-mentioned change points among the constituent fibers constituting the bottom region are large.

<30>

The absorbent article as described in the above <29>, wherein the number of fibers (N _13c ) having the above-mentioned change point in the constituent fibers constituting the side region relative to those having the above-mentioned change point among the constituent fibers constituting the top region The ratio of the number of fibers (N _13a ) or the number of fibers (N _13b ) in the constituent fibers constituting the bottom region (N _13c /N _13a , N _13c /N _13b ) having the above change point is preferably 2 It is more than 20 and less than 20, More preferably, it is more than 5 and less than 20.

<31>

The absorbent article as described in the above <30>, wherein the number of fibers (N _13a ) having the above change point among the constituent fibers constituting the top region is preferably 1 or more and 15 or less, and more preferably 5 More than 15 roots.

<32>

The absorbent article as described in the above <30> or <31>, wherein the number of fibers (N _13b ) having the above change point among the constituent fibers constituting the bottom region is preferably 1 or more and 15 or less, and It is preferably 5 or more and 15 or less.

<33>

The absorbent article as described in any one of the above <30> to <32>, wherein the number of fibers (N _13c ) having the above change point among the constituent fibers constituting the side region is preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less.

<34>

The absorbent article as described in any one of the above <1> to <33>, wherein the sheet thickness T _{S of} the non-woven fabric is preferably 0.5 mm or more and 7 mm or less, more preferably 1.0 mm or more and 5 mm or less.

<35>

The absorbent article as described in any one of <1> to <34> above, wherein the layer thickness T _L1 of the top region of the nonwoven fabric is preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.2 mm or more and Below 2.0mm.

<36>

The absorbent article as described in any one of the above <1> to <35>, wherein the layer thickness T _L2 of the bottom region of the nonwoven fabric is preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.2 mm or more and Below 2.0mm.

<37>

The absorbent article as described in any one of <1> to <36> above, wherein the layer thickness T _L3 of the side region of the nonwoven fabric is preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.2 mm or more And below 2.0mm.

<38>

The absorbent article as described in any one of the above <1> to <37>, wherein the nonwoven fabric has an X direction, which is a direction in which the convex stripe portion and the concave stripe portion extend, and The orthogonal direction is the Y direction, and the distance between the tops of the protruding strip portions adjacent in the Y direction is preferably 1 mm or more and 15 mm or less, more preferably 1.5 mm or more and 10 mm or less.

<39>

The absorbent article according to any one of <1> to <38> above, wherein the height of the convex stripe portion is preferably 0.5 mm or more and 5 mm or less, more preferably 1 mm or more and 3 mm or less.

<40>

The absorbent article as described in any one of the above <1> to <39>, wherein the basis weight of the non-woven fabric is preferably 15 g/m ² or more and 50 g/m ² or less based on the overall average value, more preferably 20g/m ² or more and 40g/m ² or less.

<41>

The absorbent article as described in any one of <1> to <40> above, wherein the lower sheet is the first of the aggregates of fibers containing thermoplastic resin disposed between the front sheet and the absorber Two sheets.

<42>

The absorbent article as described in any one of <1> to <41> above, wherein the lower sheet contains an aggregate of fibers, and the fiber density of the aggregate of fibers is higher than that of the above constituting the front sheet Non-woven fiber density.

<43>

The absorbent article as described in <42> above, wherein the constituent fibers of the lower sheet are aligned in the longitudinal direction.

<44>

The absorbent article as described in the above <42> or <43>, wherein the lower sheet contains a long fiber nonwoven fabric.

<45>

The absorbent article as described in any one of <42> to <44> above, wherein the hydrophilicity of the lower sheet is higher than that of the front sheet.

<46>

The absorbent article as described in any one of the above <42> to <45>, wherein the thickness of the above-mentioned absorber is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 15 mm or less, more preferably 10 mm Hereinafter, it is preferably 1 mm or more and 15 mm or less, and more preferably 2 mm or more and 10 mm or less.

<47>

The absorbent article as described in any one of <42> to <46> above, wherein the nonwoven fabric includes fibers having large and small diameter portions having different fiber diameters.

<48>

The absorbent article as described in any one of <42> to <47> above, wherein the non-woven fabric includes a plurality of fusion portions formed by thermally fusing intersections of constituent fibers.

<49>

The absorbent article as described in any one of <42> to <48> above, wherein the constituent fibers of the non-woven fabric include high-elongation fibers.

<50>

The absorbent article as described in <49> above, wherein the high-elongation fiber is a core-sheath composite fiber having heat fusion properties.

<51>

The absorbent article as described in the above <49> or <50>, wherein the fineness of the high-elongation fiber is 1.0 dtex or more and 10.0 dtex or less in the raw material stage, preferably 2.0 dtex or more and 8.0 dtex or less.

<52>

The absorbent article as described in any one of <49> to <51> above, wherein The ratio of the high-elongation fiber 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.

<53>

The absorbent article as described in any one of the above <42> to <52>, wherein when the constituent fibers of the non-woven fabric are focused on one constituent fiber, the diameter of the fiber is sandwiched between adjacent fusion parts. The small diameter of the two small diameter parts is the large diameter part with the larger diameter.

<54>

The absorbent article as described in the above <53>, wherein the one constituent fiber has a plurality of large-diameter portions between adjacent fusion portions.

<55>

The absorbent article as described in the above <53> or <54>, wherein when the constituent fibers of the non-woven fabric are focused on one constituent fiber 11, there are one or more and five or less between adjacent fusion parts The large-diameter portion is preferably provided with one or more and three or less.

<56>

The absorbent article as described in any one of the above <53> to <55>, wherein the ratio of the fiber diameter (diameter L ₁₆ ) of the small diameter portion to the fiber diameter (diameter L ₁₇ ) of the large diameter portion ( L ₁₆ /L ₁₇ ) is preferably 0.5 or more and 0.8 or less, and more preferably 0.55 or more and 0.7 or less.

<57>

The absorbent article as described in any one of <53> to <56> above, wherein the ratio of the fiber diameter (diameter L ₁₆ ) of the small diameter portion to the fiber diameter (diameter L ₁₇ ) of the large diameter portion ( L ₁₆ /L ₁₇ ) is preferably 0.5 or more and 0.8 or less, and more preferably 0.55 or more and 0.7 or less.

<58>

The absorbent article as described in any one of the above <53> to <57>, wherein the fiber diameter (diameter L ₁₆ ) of the small-diameter portion is preferably 5 μm or more and 28 μm or less, and more preferably 6.5 μm or more and 20 μm or less, particularly preferably 7.5 μm or more and 16 μm or less.

<59>

The absorbent article according to any one of <53> to <58>, wherein the fiber diameter (diameter L ₁₇ ) of the large-diameter portion is preferably 10 μm or more and 35 μm or less, and more preferably 13 μm or more and 25 μm Below, particularly preferably 15 μm or more and 20 μm or less.

<60>

The absorbent article as described in any one of <53> to <59> above, wherein the constituent fibers of the non-woven fabric change from a small diameter portion adjacent to the fusion portion to a large diameter portion when focusing on one constituent fiber The dots are arranged within a range of 1/3 of the interval T between the fusion part and the adjacent fusion parts.

<61>

The absorbent article as described in any one of <42> to <60> above, wherein the non-woven fabric has a top region, a bottom region, and a side region between them when viewed in cross section in the thickness direction Z, And the top of the convex strip part is formed by the top region, and the bottom of the concave strip part is formed by the bottom region.

<62>

The absorbent article according to the above <61>, 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.

<63>

The absorbent article as described in the above <61> or <62>, wherein the fiber density (D _13c ) in the side region is relative to the fiber density (D _13a ) in the top region, or the fiber density (D in the bottom region) The ratio of _13b ) (D _13c /D _13a , D _13c /D _13b ) is preferably 0.15 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less.

<64>

The absorbent article as described in any one of the above <61> to <63>, wherein the fiber density (D _13a ) of the top region 13a is preferably 90 pieces/mm ² or more and 200 pieces/mm ² or less, and It is preferably 100 pieces/mm ² or more and 180 pieces/mm ² or less.

<65>

The absorbent article as described in any one of <61> to <64> above, wherein the fiber density (D _13b ) of the bottom region 13b is preferably 80 pieces/mm ² or more and 200 pieces/mm ² or less, and It is preferably 90 pieces/mm ² or more and 180 pieces/mm ² or less.

<66>

The absorbent article as described in any one of <61> to <65> above, wherein the fiber density (D _13c ) of the side region 13c is preferably 30 pieces/mm ² or more and 80 pieces/mm ² or less, Furthermore, it is preferably 40 pieces/mm ² or more and 70 pieces/mm ² or less.

<67>

The absorbent article as described in any one of <60> to <66> above, is formed such that the number of fibers having a change point among the constituent fibers constituting the side region is higher than the constituent fibers constituting the top region The number of fibers with change points in the middle and the number of fibers with change points in the constituent fibers constituting the above-mentioned bottom region are large.

<68>

The absorbent article as described in any one of <62> to <67> above, wherein the number of fibers (N _13c ) having a change point among the constituent fibers constituting the side region is relative to the composition constituting the top region The number of fibers (N _13a ) with changing points in the fiber, or the ratio of the number of fibers (N _13b ) with changing points in the constituent fibers constituting the above-mentioned bottom region (N _13c /N _13a , N _13c /N _13b ) Is preferably 2 or more and 20 or less, and more preferably 5 or more and 20 or less.

<69>

The absorbent article as described in any one of the above <62> to <68>, wherein the specific value of the number of fibers of the non-woven fabric having a change point is a fiber having a change point among the constituent fibers constituting the top region The number (N _13a ) is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less.

<70>

The absorbent article as described in any one of the above <62> to <69>, wherein the specific value of the number of fibers of the non-woven fabric having a change point has a change point of 18 among the constituent fibers constituting the bottom region The number of fibers (N _13b ) is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less.

<71>

The absorbent article as described in any one of the above <62> to <70>, wherein the specific value of the number of fibers of the non-woven fabric having a change point has a change point of 18 in the constituent fibers constituting the side region The number of fibers (N _13c ) is preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less.

<72>

The absorbent article as described in any one of the above <42> to <71>, wherein the sheet thickness T _S of the non-woven fabric is 0.5 mm or more and 7 mm or less, preferably 1.0 mm or more and 5 mm or less.

<73>

The absorbent article as described in any one of <42> to <72> above, wherein the layer thickness T _L1 of the top region is 0.1 mm or more and 3.0 mm or less, preferably 0.2 mm or more and 2.0 mm or less.

<74>

The absorbent article as described in any one of <42> to <73> above, wherein the layer thickness T _L2 of the bottom region is 0.1 mm or more and 3.0 mm or less, preferably 0.2 mm or more and 2.0 mm or less.

<75>

The absorbent article as described in any one of the above <42> to <74>, wherein the layer thickness T _L3 of the side region is 0.1 mm or more and 3.0 mm or less, preferably 0.2 mm or more and 2.0 mm or less.

<76>

The absorbent article as described in any one of <42> to <75> above, wherein the distance between the tops of the ridge portions adjacent in the width direction Y is 1 mm or more and 15 mm or less, preferably 1.5 mm Above and below 10mm.

<77>

The absorbent article as described in any one of <42> to <76> above, wherein the height H of the convex stripe portion is 0.5 mm or more and 5 mm or less, preferably 1 mm or more and 3 mm or less.

<78>

The absorbent article as described in any one of <42> to <77> above, wherein it is more preferable that the basis weight of the nonwoven fabric is 15 g/m ² or more and 50 g/m ² or less based on the average value of the entire sheet , It is preferably 20 g/m ² or more and 40 g/m ² or less.

<79>

The absorbent article as described in any one of <42> to <78> above, wherein the lower sheet is spunbonded nonwoven fabric or spunlace nonwoven fabric.

<80>

The absorbent article as described in any one of the above <42> to <79>, wherein the fiber density (D ₆ ) of the lower sheet or the second sheet as the lower sheet is relative to the ridges The fiber density (D _13a ) ratio (D ₆ /D _13a ) of the top of the portion (top region 13a) is preferably 1.1 or more, and more preferably 2 or more.

<81>

The absorbent article as described in any one of the above <42> to <80>, wherein the absorbent body has a plurality of high-density portions having a higher fiber density than parts located on both sides in the width direction at a plurality of positions in the width direction, And each of the high-density parts is formed on the convex part The position where the top overlaps.

<82>

The absorbent article according to the above <81>, wherein the high-density portion extends along the longitudinal direction and forms a plurality of rows in the width direction, and each of the high-density portions is continuous with the top of the convex strip portion along the longitudinal direction地 overlapping.

<83>

The absorbent article as described in the above <81> or <82>, wherein the number of high-density portions formed along the width direction Y of the absorbent body and overlapping the top of the convex strip portion of the front sheet is plural, It is preferably 3 or more, more preferably 5 or more, and still more preferably 8 or more.

<84>

The absorbent article as described in any one of the above <81> to <83>, wherein the length of the high-density portion in the width direction Y is preferably 20 mm or more, and more preferably 50 mm or more.

<85>

The absorbent article according to any one of the above <81> to <84>, wherein as the high density portion, a high density portion having a shape elongated in the longitudinal direction X is continuously formed along the longitudinal direction X of the absorber .

<86>

The absorbent article according to any one of the above <81> to <85>, wherein the length of the high-density portion continuous in the longitudinal direction X is preferably 30% or more with respect to the total length of the absorbent body in the same direction, It is more preferably 50% or more, and further preferably 100%.

<87>

The absorbent article according to any one of the above <81> to <86>, wherein the high-density portion has a shape that is long in the longitudinal direction X, and a plurality of intermittently formed along the longitudinal direction X of the absorbent body 4 Pcs.

<88>

The absorbent article according to any one of the above <81> to <87>, wherein the length L3 of the high-density portion in the longitudinal direction X is preferably 0.5 mm or more, and more preferably 1 mm or more.

<89>

The absorbent article as described in any one of the above <81> to <88>, wherein the length L3 of the high-density portion is the length between the length L3 and the high-density portion adjacent in the longitudinal direction X The total length L5 is preferably 5% or more, and more preferably 30% or more.

<90>

The absorbent article as described in any one of the above <81> to <89>, wherein the ratio of the density (D ₄ ) of the density of the low density portion to the density (D ₃ ) of the above high density portion (D ₃ /D ₄ ) It is preferably 1.5 or more, and more preferably 3 or more.

<91>

The absorbent article as described in any one of the above <42> to <90>, wherein the front sheet and the lower sheet contain fibers of a thermoplastic resin, and the concave portion is thermally fused to the lower side The sheet is joined, and at this joined portion, the constituent fibers of the front sheet and the lower sheet do not maintain the form of the fibers.

<92>

The absorbent article as described in any one of <42> to <91> above, wherein the joining portion of the concave strip portion and the lower sheet is liquid-impermeable.

<93>

The absorbent article as described in any one of <42> to <92> above, wherein the joining portion is formed continuously along the longitudinal direction.

<94>

An absorbent article having a liquid-permeable front sheet, a back sheet and an absorber interposed between these two sheets, which has a longitudinal direction And the width direction, the front sheet includes a non-woven fabric of a concave-convex structure in which stripe-shaped convex stripe portions and concave stripe portions extending in the longitudinal direction are alternately arranged in the width direction, and on the concave stripe portion and the adjacent lower side Sheet joining, the convex strip portion has a hollow structure between the lower sheet, the lower sheet contains an aggregate of fibers, and the fiber density of the aggregate of fibers is higher than that of the nonwoven fabric constituting the front sheet The fiber density.

<95>

The absorbent article as described in the above <94>, wherein the constituent fibers of the lower sheet are aligned in the longitudinal direction.

<96>

The absorbent article as described in the above <94> or <95>, wherein the lower sheet contains a long fiber nonwoven fabric.

<97>

The absorbent article as described in any one of <94> to <96> above, wherein the hydrophilicity of the lower sheet is higher than that of the front sheet.

<98>

The absorbent article as described in any one of the above <94> to <97>, wherein the thickness of the absorber is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 15 mm or less, more preferably 10 mm Hereinafter, it is preferably 1 mm or more and 15 mm or less, and more preferably 2 mm or more and 10 mm or less.

<99>

The absorbent article as described in any one of <94> to <98> above, wherein the nonwoven fabric includes fibers having large and small diameter portions having different fiber diameters.

<100>

The absorbent article as described in any one of <94> to <99> above, in which The nonwoven fabric includes a plurality of fusion parts formed by thermally fusing the intersections of the constituent fibers.

<101>

The absorbent article as described in any one of <94> to <100> above, wherein the constituent fibers of the non-woven fabric include high-elongation fibers.

<102>

The absorbent article as described in <101> above, wherein the high-elongation fiber is a core-sheath composite fiber having heat fusion properties.

<103>

The absorbent article according to the above <101> or <102>, wherein the fineness of the high-elongation fiber is 1.0 dtex or more and 10.0 dtex or less in the raw material stage, preferably 2.0 dtex or more and 8.0 dtex or less.

<104>

The absorbent article as described in any one of <101> to <103> above, wherein the ratio of the high-elongation fiber 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.

<105>

The absorbent article as described in any one of the above <94> to <104>, wherein when the constituent fibers of the non-woven fabric are focused on one constituent fiber, the diameter of the fiber is sandwiched between adjacent fusion parts. The small diameter of the two small diameter parts is the large diameter part with the larger diameter.

<106>

The absorbent article as described in <105> above, wherein the one constituent fiber has a plurality of large-diameter portions between adjacent fusion portions.

<107>

The absorbent article as described in the above <105> or <106>, wherein the constituent fibers of the non-woven fabric focus on one constituent fiber 11 between adjacent fusion parts It is preferable to have one or more and five or less large diameter portions, preferably one or more and three or less.

<108>

The absorbent article as described in any one of <105> to <107> above, wherein the ratio of the fiber diameter (diameter L ₁₆ ) of the small diameter portion to the fiber diameter (diameter L ₁₇ ) of the large diameter portion ( L ₁₆ /L ₁₇ ) is preferably 0.5 or more and 0.8 or less, and more preferably 0.55 or more and 0.7 or less.

<109>

The absorbent article as described in any one of <105> to <108> above, wherein the ratio of the fiber diameter (diameter L ₁₆ ) of the small diameter portion to the fiber diameter (diameter L ₁₇ ) of the large diameter portion ( L ₁₆ /L ₁₇ ) is preferably 0.5 or more and 0.8 or less, and more preferably 0.55 or more and 0.7 or less.

<110>

The absorbent article as described in any one of <105> to <109> above, wherein the fiber diameter (diameter L ₁₆ ) of the small-diameter portion is preferably 5 μm or more and 28 μm or less, and more preferably 6.5 μm or more and 20 μm or less, particularly preferably 7.5 μm or more and 16 μm or less.

<111>

The absorbent article according to any one of <105> to <110>, wherein the fiber diameter (diameter L ₁₇ ) of the large-diameter portion is preferably 10 μm or more and 35 μm or less, and more preferably 13 μm or more and 25 μm Below, particularly preferably 15 μm or more and 20 μm or less.

<112>

The absorbent article as described in any one of <105> to <111> above, wherein the constituent fibers of the non-woven fabric change from a small diameter portion adjacent to the fusion portion to a large diameter portion when focusing on one constituent fiber The dots are arranged within a range of 1/3 of the interval T between the fusion part and the adjacent fusion parts.

<113>

The absorbent article as described in any one of <94> to <112> above, wherein The non-woven fabric has a top region, a bottom region, and a side region between them when viewed in cross-section along the thickness direction Z, and the top of the convex strip part is formed by the top region, and the bottom of the concave strip part is formed by the bottom region form.

<114>

The absorbent article as described in the above <113>, 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.

<115>

The absorbent article as described in the above <113> or <114>, wherein the fiber density of the side region (D _13c ) relative to the fiber density of the top region (D _13a ) or the fiber density of the bottom region (D The ratio of _13b ) (D _13c /D _13a , D _13c /D _13b ) is preferably 0.15 or more and 0.9 or less, and more preferably 0.2 or more and 0.8 or less.

<116>

The absorbent article as described in any one of <113> to <115> above, wherein the fiber density (D _13a ) of the top region 13a is preferably 90 pieces/mm ² or more and 200 pieces/mm ² or less, and It is preferably 100 pieces/mm ² or more and 180 pieces/mm ² or less.

<117>

The absorbent article according to any one of the above <113> to <116>, wherein the fiber density (D _13b ) of the bottom region 13b is preferably 80 pieces/mm ² or more and 200 pieces/mm ² or less, and It is preferably 90 pieces/mm ² or more and 180 pieces/mm ² or less.

<118>

The absorbent article as described in any one of the above <113> to <117>, wherein the fiber density (D _13c ) of the side region 13c is preferably 30 pieces/mm ² or more and 80 pieces/mm ² or less, Furthermore, it is preferably 40 pieces/mm ² or more and 70 pieces/mm ² or less.

<119>

The absorbent article as described in any one of <112> to <118> above, is formed such that the number of fibers having a change point among the constituent fibers constituting the side region is more than the constituent fibers constituting the top region The number of fibers having change points in the middle and the number of fibers having change points constituting the fibers constituting the bottom region are large.

<120>

The absorbent article as described in any one of the above <114> to <119>, wherein the number of fibers (N _13c ) having change points among the constituent fibers constituting the side region is relative to the composition constituting the top region The number of fibers (N _13a ) with changing points in the fiber, or the ratio of the number of fibers (N _13b ) with changing points in the constituent fibers constituting the above-mentioned bottom region (N _13c /N _13a , N _13c /N _13b ) Is preferably 2 or more and 20 or less, and more preferably 5 or more and 20 or less.

<121>

The absorbent article as described in any one of the above <114> to <120>, wherein the specific value of the number of fibers of the non-woven fabric having a change point is a fiber having a change point among the constituent fibers constituting the top region The number (N _13a ) is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less.

<122>

The absorbent article as described in any one of the above <114> to <121>, wherein the specific value of the number of fibers of the non-woven fabric having a change point has a change point of 18 among the constituent fibers constituting the bottom region The number of fibers (N _13b ) is preferably 1 or more and 15 or less, and more preferably 5 or more and 15 or less.

<123>

The absorbent article as described in any one of the above <114> to <122>, wherein the specific value of the number of fibers of the nonwoven fabric having a change point has a change point 18 in the constituent fibers constituting the side region The number of fibers (N _13c ) is preferably 5 or more and 20 or less, and more preferably 10 or more and 20 or less.

<124>

The absorbent article according to any one of the above <94> to <123>, wherein the sheet thickness T _S of the nonwoven fabric is 0.5 mm or more and 7 mm or less, preferably 1.0 mm or more and 5 mm or less.

<125>

The absorbent article as described in any one of <94> to <124> above, wherein the layer thickness T _L1 of the top region is 0.1 mm or more and 3.0 mm or less, preferably 0.2 mm or more and 2.0 mm or less.

<126>

The absorbent article as described in any one of the above <94> to <125>, wherein the layer thickness T _L2 of the bottom region is 0.1 mm or more and 3.0 mm or less, preferably 0.2 mm or more and 2.0 mm or less.

<127>

The absorbent article as described in any one of the above <94> to <126>, wherein the layer thickness T _L3 of the side region is 0.1 mm or more and 3.0 mm or less, preferably 0.2 mm or more and 2.0 mm or less.

<128>

The absorbent article as described in any one of the above <94> to <127>, wherein the distance between the tops of the convex stripe portions adjacent in the width direction Y is 1 mm or more and 15 mm or less, preferably 1.5 mm Above and below 10mm.

<129>

The absorbent article as described in any one of <94> to <128> above, wherein the height H of the convex stripe portion is 0.5 mm or more and 5 mm or less, preferably 1 mm or more and 3 mm or less.

<130>

The absorbent article as described in any one of <94> to <129> above, more preferably, the basis weight of the non-woven fabric is 15 g/m ² or more and 50 g/m ² or less based on the average value of the entire sheet , It is preferably 20 g/m ² or more and 40 g/m ² or less.

<131>

The absorbent article as described in any one of <94> to <130> above, wherein the lower sheet is spunbonded nonwoven fabric or spunlace nonwoven fabric.

<132>

The absorbent article as described in any one of the above <94> to <131>, wherein the fiber density (D ₆ ) of the lower sheet or the second sheet as the lower sheet is relative to the ridges The fiber density (D _13a ) ratio (D ₆ /D _13a ) of the top of the portion (top region 13a) is preferably 1.1 or more, and more preferably 2 or more.

<133>

The absorbent article according to any one of the above <94> to <132>, wherein the absorbent body has a plurality of high-density portions having a higher fiber density than the portions located on both sides in the width direction in the plurality of positions in the width direction, Each of the high-density portions is formed at a position overlapping with the top of the convex portion.

<134>

The absorbent article as described in the above <133>, wherein the high-density portion extends along the longitudinal direction and forms a plurality of rows in the width direction, and each of the high-density portions is along the longitudinal direction and the top of the convex strip portion Continuously overlap.

<135>

The absorbent article as described in the above <133> or <134>, wherein the number of high-density portions formed along the width direction Y of the absorbent body and overlapping the top of the convex strip portion of the front sheet is a plurality, It is preferably 3 or more, more preferably 5 or more, and still more preferably 8 or more.

<136>

The absorbent article as described in any one of <133> to <135> above, wherein The length of the high-density portion in the width direction Y is preferably 20 mm or more, and more preferably 50 mm or more.

<137>

The absorbent article as described in any one of <133> to <136> above, wherein the high-density portion having a shape elongated in the longitudinal direction X as the high-density portion is continuous along the longitudinal direction X of the absorbent body form.

<138>

The absorbent article according to any one of the above <133> to <137>, wherein the length of the high-density portion continuous in the longitudinal direction X is preferably 30% or more with respect to the total length of the absorbent body in the same direction, It is more preferably 50% or more, and further preferably 100%.

<139>

The absorbent article according to any one of the above <133> to <138>, wherein the high-density portion has a shape that is long in the longitudinal direction X, and a plurality of intermittently formed along the longitudinal direction X of the absorbent body 4 Pcs.

<140>

The absorbent article as described in any one of the above <133> to <139>, wherein the length L3 of the high-density portion in the longitudinal direction X is preferably 0.5 mm or more, and more preferably 1 mm or more.

<141>

The absorbent article as described in any one of the above <133> to <140>, wherein the length L3 of the high-density portion is the length between the length L3 and the high-density portion adjacent in the longitudinal direction X The total length L5 is preferably 5% or more, and more preferably 30% or more.

<142>

The absorbent article as described in any one of <133> to <141> above, wherein the ratio of the density (D ₄ ) of the density of the low-density portion to the density (D ₃ ) of the above-mentioned high-density portion (D ₃ /D ₄ ) It is preferably 1.5 or more, and more preferably 3 or more.

<143>

The absorbent article as described in any one of <94> to <142> above, wherein the front sheet and the lower sheet contain fibers of a thermoplastic resin, and the recessed portion is thermally fused to the lower side The sheet is joined, and at this joined portion, the constituent fibers of the front sheet and the lower sheet do not maintain the form of the fibers.

<144>

The absorbent article as described in any one of <94> to <143> above, wherein the junction between the concave strip portion and the lower sheet is liquid-impermeable.

<145>

The absorbent article as described in any one of <94> to <144> above, wherein the joining portion is formed continuously along the longitudinal direction.

[Industry availability]

According to the present invention, a concave-convex structure of a front sheet material is easy to follow the action of a wearer, and the skin has good air permeability on the facing side, and is not likely to cause a hot stuffy absorbent article.

In addition, according to the absorbent article of the present invention, the unpleasant feeling caused by the contact of the excretory fluid with the skin of the wearer can be surely suppressed, and the absorption capacity of the absorbent body can be effectively used.

1‧‧‧nonwoven

2‧‧‧Front sheet

11‧‧‧ Fiber

13‧‧‧Projection

14‧‧‧recessed part

14s‧‧‧Joint

H‧‧‧ Height

X‧‧‧length direction

Y‧‧‧Width direction

Z‧‧‧thickness direction

Claims (30)

An absorbent article comprising a liquid-permeable front sheet, a back sheet, and an absorber interposed between these two sheets, which has a longitudinal direction and a width direction. The sheet material includes a non-woven fabric with a concave-convex structure in which stripe-shaped convex stripe portions and concave stripe portions extending in the longitudinal direction are alternately arranged in the width direction, and is joined to the adjacent lower sheet at the concave stripe portion. If at least high-elongation fiber is used as the raw material, the lower sheet contains an aggregate of fibers of a thermoplastic resin, the convex portion has a hollow structure between the nonwoven fabric and the lower sheet, and the nonwoven fabric has a top region and a bottom Region, and a side region between them, the top of the convex strip part is formed by the top region, the bottom of the concave strip part is formed by the bottom region, the fiber density of the side region is higher than that of the fiber of the top region Either the density or the fiber density of the bottom region is low, and the central region in the width direction of the absorbent article has at least the uneven structure. The absorbent article according to claim 1, wherein the convex portion can maintain a hollow structure in a state where a load of 4 g/cm ² is applied to the absorbent article from the front sheet side. The absorbent article according to claim 1, wherein the joining of the front sheet and the lower sheet is intermittently performed in the direction in which the convex stripe extends. The absorbent article according to claim 1, wherein the width of the absorbent body in the central region of at least the longitudinal direction of the absorbent article is greater than the width of the front sheet and the above Any one of the width of the lower sheet is narrow, and at least in the central region in the longitudinal direction of the absorbent article, each side edge of the absorbent body is linear and extends with the convex stripe and the concave stripe The directions are roughly parallel. The absorbent article according to claim 1, wherein each side edge of the above-mentioned absorbent article is in the shape of a combined curve, and each side edge of the above-mentioned absorbent article is convexly curved toward the outer side in the width direction in the longitudinal front area and the rear area And, in the central region in the longitudinal direction, each side edge is convexly curved toward the inner side in the width direction, whereby the width of the central region in the longitudinal direction becomes the narrowest. The absorbent article according to claim 1, wherein the front sheet and the back sheet are joined at the peripheral edge of the absorbent article, and the front sheet has the concave-convex structure in the entire region of the inner side of the peripheral edge . The absorbent article according to claim 1, wherein the convex portion can maintain a hollow structure in a state where a load of 20 g/cm ² is applied from the front sheet side of the absorbent article. The absorbent article according to claim 1, wherein the non-woven fabric includes fibers having large-diameter portions and small-diameter portions having different fiber diameters. The absorbent article according to claim 1, wherein the non-woven fabric includes a plurality of fusion parts formed by thermally fusing intersections of the constituent fibers. The absorbent article of the requested item 1, wherein the fiber density of the side area D _13c relative to the fiber density of said top area D _13a, or the ratio of fiber area density of said bottom i.e. the D _13b D _13c / D _13a or D _13c /D _13b is 0.15 or more and 0.9 or less. The absorbent article according to claim 1, where one of the constituent fibers of the non-woven fabric is focused on, the constituent fibers have a sandwich between adjacent fusion parts The large-diameter part with the larger fiber diameter in the two small-diameter parts with the smaller fiber diameter. The absorbent article according to claim 11, wherein when focusing on one of the constituent fibers, a plurality of the large-diameter portions are provided between the adjacent fusion-bonding portions. The absorbent article according to claim 11 or 12, wherein the ratio of the fiber diameter L ₁₆ of the small diameter portion to the fiber diameter L ₁₇ of the large diameter portion, that is, L ₁₆ /L ₁₇ is 0.5 or more and 0.8 or less. The absorbent article according to claim 11, wherein the fiber diameter L ₁₆ of the small-diameter portion is 5 μm or more and 28 μm or less. The absorbent article according to claim 11, wherein the fiber diameter L ₁₇ of the large-diameter portion is 10 μm or more and 35 μm or less. The absorbent article according to claim 11, wherein the non-woven fabric includes fibers having large-diameter portions and small-diameter portions having different fiber diameters, and in the non-woven fabric, the constituent fibers constituting the side regions have self-adjacent to the above The number of fibers at the change point from the small diameter portion of the fusion portion to the large diameter portion is greater than the number of fibers having the change point among the constituent fibers constituting the top region and the constituent fibers constituting the bottom region The number of fibers at the above change point is large. The absorbent article according to claim 1, wherein the lower sheet is a second sheet of an aggregate containing fibers of a thermoplastic resin disposed between the front sheet and the absorber. The absorbent article according to claim 1, wherein the lower sheet contains an aggregate of fibers, and the fiber density of the aggregate of fibers is higher than the fiber density of the nonwoven fabric constituting the front sheet. The absorbent article according to claim 1, wherein the constituent fibers of the above lower sheet are aligned in the longitudinal direction. The absorbent article according to claim 1, wherein the above-mentioned lower sheet contains long fiber nonwoven cloth. The absorbent article according to claim 1, wherein the hydrophilicity of the lower sheet is higher than that of the front sheet. The absorbent article according to claim 1, wherein the absorbent body has a plurality of high-density portions having a higher fiber density than the portions located on both sides in the width direction in the plurality of positions in the width direction, and each of the high-density portions is formed The position where the tops of the convex strips overlap. The absorbent article according to claim 22, wherein the number of the high-density portions formed in the width direction of the absorbent body overlapping the top of the convex strip portion of the front sheet is a plurality. The absorbent article according to claim 22 or 23, wherein, as the high-density portion, a high-density portion having a shape elongated in the longitudinal direction is continuously formed along the longitudinal direction of the absorbent body. The absorbent article according to claim 22, wherein the high-density portion has a shape that is long in the longitudinal direction, and a plurality of the intermittently formed along the longitudinal direction of the absorbent body. The absorbent article according to claim 22, wherein the high-density portion extends in the longitudinal direction and forms a plurality of rows in the width direction, and each of the high-density portions continuously overlaps the top of the convex strip portion in the longitudinal direction. The absorbent article according to claim 1, wherein the front sheet and the lower sheet include fibers of a thermoplastic resin, and the concave strip portion is joined to the lower sheet by thermal fusion, and at the joint portion, the front surface The constituent fibers of the sheet and the aforementioned lower sheet do not maintain the form of the fibers. The absorbent article according to claim 1, wherein the junction between the concave portion and the lower sheet is liquid-impermeable. The absorbent article according to claim 1, wherein the joint portion is continuously formed in the longitudinal direction to make. The absorbent article according to claim 1, wherein the ratio of the fiber density D ₆ of the lower sheet or the second sheet as the lower sheet to the fiber density D _13a of the top region is D ₆ /D _13a 1.1 or more.

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