JP7634145B2 - Pants-type absorbent article - Google Patents

Description

The present invention relates to a pants-type absorbent article.

Various proposals have been made for pants-type absorbent articles. Patent Document 1 discloses a pants-type absorbent article that includes an absorbent body and an exterior body that supports the absorbent body, the exterior body being composed of a ventral part, a dorsal part, and a crotch part interposed between them, and includes a welded region between the side edge of the ventral part and the side edge of the dorsal part, which includes a welded joint that forms a waist opening and a leg opening, and an elastic stretchable member that is disposed around almost the entire circumference of each peripheral part of the waist opening and the leg opening and forms continuous gathers, and the welded joint has a non-welded part with a length of 1 cm or more at approximately the center in the width direction. It is described that the pants-type absorbent article has a good fit while maintaining a good wearing feeling and texture (paragraph 0022).

However, the continuous gathers mentioned above characterize the appearance of pants-type absorbent articles such as disposable diapers, and result in a significant difference in appearance from underwear made of cloth or the like. The elastic threads visible through the gathered portions, particularly around the stomach and buttocks, and the numerous large wrinkles around them, do not exist in cloth underwear. For wearers who do not want third parties to know that they are using a pants-type absorbent article, such differences in appearance are undesirable, and there is a demand for pants-type absorbent articles that have an appearance closer to that of cloth underwear.

In order to improve the appearance problems of pants-type absorbent articles, a composite sheet that is a laminate of a nonwoven fabric, which is a surface material, and an elastic film has been proposed as an exterior body. Patent Document 2 discloses an elastic composite sheet that is a laminate having biaxial elastic stretchability and breathability, which includes a breathable elastic film containing one or more polymers selected from polyurethane, polyether amide, and polyester elastomer, and a spunbonded nonwoven fabric that is bonded to the elastic film and can be stretched in two perpendicular directions, and further discloses an exterior body of a diaper and a personal care product that uses the elastic composite sheet.

In addition, in pants-type absorbent articles, an absorbent body that absorbs bodily fluids is fixed to the skin-side surface of the outer body so that it abuts against the wearer's crotch. However, conventional absorbent fiber-type absorbents that contain absorbent fibers such as fluff pulp and superabsorbent polymers (hereinafter also referred to as "SAP") become relatively thick after absorbing bodily fluids once, making the wearer's crotch area feel cramped and reducing the wearing comfort, and are not suitable for absorbing bodily fluids multiple times, which is the current trend in absorbent articles. Simply making the absorbent fiber-type absorbent body thinner will result in gaps between the absorbent body and the leg area of the outer body, making it easier for bodily fluids to leak and reducing the amount of bodily fluid absorbed. Therefore, the use of a thin absorbent sheet that contains two hydrophilic nonwoven fabrics and a superabsorbent polymer fixed between them with an adhesive has been considered, and various proposals have been made.

Patent Document 3 discloses an absorbent sheet as an absorbent body, which includes a first sheet, a second sheet disposed opposite the first sheet, and SAP disposed between the first and second sheets, the first sheet having an adhesive-coated surface facing the second sheet, the second sheet having an adhesive-coated surface facing the first sheet, and the SAP intermittently bonded in stripes to the adhesive-coated surface of the first sheet and/or the second sheet in the width direction, and both sides in the width direction are sealed by bonding the adhesive-coated surfaces of the first sheet and the second sheet together. Patent Document 2 describes that the absorbent body can be made smaller while ensuring the absorption performance of the absorbent body (paragraph 0012).

Japanese Patent Application Publication No. 10-137287 JP 2008-279774 A JP 2006-158676 A

When the elastic composite sheet described in Patent Document 2 is used as an outer body, if the entire surface of the absorbent body is fixed to the elastic composite sheet in the usual manner, the elastic film impedes breathability at the fixed portion between the absorbent body and the elastic composite sheet (hereinafter also simply referred to as the "fixed portion"), which makes the product prone to becoming stuffy when worn. In addition, the fixed portion becomes hard, and the overall feel of the pants-type absorbent article deteriorates. In order to improve breathability, it is possible to increase the number of fixed portions per unit area by dotting small areas of the absorbent body rather than fixing the entire surface of the absorbent body, but even in this case, the problem of the outer body feeling hard is not sufficiently solved.

The absorbent sheet described in Patent Document 3 is thin, but has the problem that repeated absorption is poor (slow) because the SAP absorbs and swells the first body fluid, causing gel blocking and blocking the passage of the body fluid. Furthermore, conventional absorbent sheets have the problem that the SAP is densely arranged, making the absorbent sheet hard and reducing the comfort of wearing it, and the nonwoven fabric made of plastic resin that makes up the absorbent sheet does not have the function to instantly receive the body fluid before the SAP starts to absorb it, so it cannot absorb the first body fluid, resulting in leakage or backflow.

The object of the present invention is to provide a pants-type absorbent article that uses a stretchable composite sheet as an exterior body, has excellent stretchability, breathability, and texture, has a good appearance, and prevents leakage of body fluids.

As a result of intensive research conducted by the inventors to solve the above problems, they discovered that by integrating a nonwoven fabric and a stretchable film by interposing a plurality of mutually spaced joints having a predetermined shape in a plan view between the nonwoven fabric and the stretchable film, it is possible to obtain a stretchable composite sheet that has a predetermined airflow resistance value, good stretchability, is pleasant to the touch, and can be suitably used as an exterior body for a pants-type absorbent article, and further that by combining the stretchable composite sheet with a predetermined absorbent sheet as an absorbent body, a desired pants-type absorbent article can be obtained, thus completing the present invention. That is, the present invention relates to the following pants-type absorbent article.

(1) A pants-type absorbent article comprising an exterior body divided into a ventral side portion, a crotch portion, and a back side portion, and an absorbent body that is supported mainly by the crotch portion of the exterior body and absorbs body fluids,
The absorbent body includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent sheet disposed therebetween, the absorbent sheet including a hydrophilic nonwoven fabric that diffuses bodily fluids in a surface direction and a thickness direction, and a highly absorbent polymer layer that absorbs bodily fluids, and a pulp sheet that temporarily retains bodily fluids on the side closest to the wearer's skin,
The exterior body includes a composite sheet including a plurality of nonwoven fabrics, a stretchable film disposed between the nonwoven fabrics, and a plurality of joints spaced apart from each other in a surface direction to integrate the nonwoven fabrics and the stretchable film,
The composite sheet has an air flow resistance value in the range of 0.01 kPa·s/m or more and 0.5 kPa·s/m or less when stretched 250% in the stretch direction,
Each of the joints has a shape in plan view that has corners derived from a rectangle and partial arc portions derived from a circle,
The pants-type absorbent article further has waist gathers, which are arranged circumferentially along a waist opening formed by joining both widthwise ends of the abdominal side portion and both widthwise ends of the back side portion, and which include an elastic stretchable member.
(2) A pants-type absorbent article according to (1) above, which has a boxer-shorts-type appearance.
(3) The pants-type absorbent article according to (1) or (2) above, wherein the composite sheet has an elongation rate in the stretch direction of 150% or more and 270% or less.
(4) The pants-type absorbent article according to any one of (1) to (3) above, wherein the number of the elastically stretchable members is 3 or more and 8 or less.
(5) A pants-type absorbent article according to any one of (1) to (4) above, wherein the absorbent sheet is a first absorbent sheet formed by layering, from the wearer's skin side, a first hydrophilic nonwoven fabric, a first highly absorbent polymer layer, a second hydrophilic nonwoven fabric, a second highly absorbent polymer, and a pulp sheet.
(6) A pants-type absorbent article according to any one of (1) to (4) above, wherein the absorbent sheet is a second absorbent sheet formed by stacking, in order from the wearer's skin side, the first hydrophilic nonwoven fabric, the first superabsorbent polymer layer, the second hydrophilic nonwoven fabric, the second superabsorbent polymer, the third hydrophilic nonwoven fabric, the third superabsorbent polymer layer, and the pulp sheet.
(7) A pants-type absorbent article of any of (1) to (6) above, wherein the absorbent sheet has an embossed groove extending from its skin-side surface to the skin-side surface of the pulp sheet, the embossed groove including a first embossed groove extending longitudinally through the widthwise center of the skin-side surface of the absorbent sheet, and a second embossed groove including a plurality of embossed grooves intersecting or contacting the first embossed groove at an acute angle.
(8) The absorbent article of (7) above, wherein the second embossed groove is provided on the skin-facing surface of the absorbent sheet in an X-shape when viewed in a plane, and the intersection of the X-shape is located on the first embossed groove.
(9) The pants-type absorbent article according to any one of (1) to (8) above, wherein the absorbent sheet has a thickness of 0.5 mm or more and 5 mm or less.
(10) The pants-type absorbent article according to any one of (1) to (9), wherein the hydrophilic nonwoven fabric has a basis weight of 10 g/ ^m2 or more and 40 g/ ^m2 or less and a thickness of 0.05 mm or more and 0.3 mm or less.
(11) The pants-type absorbent article according to any one of (1) to (10) above, wherein the pulp sheet has a basis weight of 10 g/ ^m2 or more and 40 g/ ^m2 or less and a thickness of 0.05 mm or more and 0.5 mm or less.

The present invention provides a pants-type absorbent article that uses a stretchable composite sheet as an exterior body, has excellent stretchability, breathability, and texture, has a good appearance, and prevents leakage of bodily fluids.

FIG. 1 is a perspective view showing a schematic appearance of a pants-type absorbent article according to an embodiment of the present invention. FIG. 2 is a schematic development view of the pants-type absorbent article shown in FIG. 1 . 3 is a schematic cross-sectional view in the width direction taken along the line XX in FIG. 2. 1 is a schematic plan view showing a joint, in which (a) shows the main dimensions of the joint, (b) shows the main angles when the joint is arranged, and (c) shows the main arrangement pattern of the joint. 1A is a schematic side view showing all steps of a composite sheet manufacturing method according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing an enlarged view of a third step (adhesion step). FIG. 2 is a schematic cross-sectional view showing the configuration of an absorbent sheet precursor before embossed grooves are formed. FIG. 4 is a cross-sectional view showing a schematic configuration of an absorbent sheet precursor in another embodiment. FIG. 2 is a plan view showing a schematic configuration of embossed grooves in an absorbent sheet. 9A and 9B are schematic cross-sectional views in the width direction of the absorbent sheet shown in Fig. 8. Fig. 9A is a schematic cross-sectional view taken along the X ₁ -X ₁ cutting line shown in Fig. 7, and Fig. 9B is a schematic cross-sectional view taken along the X ₂ -X ₂ cutting line shown in Fig. 7.

In this specification, wearing the pants-type absorbent article 50 refers to the state in which it is attached to the wearer's body, regardless of whether it is before or after absorbing bodily fluids. The longitudinal direction of the pants-type absorbent article 50 is the direction indicated by Y in the figure, which extends from front to back through the wearer's crotch when the absorbent article 50 is worn, the width direction is the direction indicated by X in the figure, which is approximately perpendicular to the longitudinal direction, and the thickness direction is the direction indicated by Z in the figure in which the components are stacked. The skin-side surfaces of the pants-type absorbent article 50 and each of its components are the surfaces that contact the wearer's skin or face the skin, and the non-skin-side surfaces are the surfaces that contact the wearer's clothing or face the clothing. Body fluids refer to liquids discharged from the body to the outside, such as urine, blood, and water in loose stools.

<Pants-type absorbent article>
Hereinafter, the pants-type absorbent article 50 of this embodiment will be described with reference to the drawings. Figs. 1 to 4 show the pants-type absorbent article 50. Fig. 5 shows a manufacturing method of the composite sheet constituting the exterior body 1 of the pants-type absorbent article 50. Figs. 6 and 7 show absorbent sheet precursors 20A and 25A, respectively. Figs. 8 and 9 show an absorbent sheet used as the absorbent sheet 20. The figures do not specify the shape of the absorbent article 50 and each of the components, the size relationship, etc. of the absorbent article 50 and each of the components. The pants-type absorbent article 50 of this embodiment can be suitably used as a pants-type paper diaper for infants, adults, and the elderly.

As shown in Figs. 1 to 3, the pants-type absorbent article 50 of this embodiment includes an exterior body 1 that forms a boxer-short outer shape, and an absorbent body 51 that is supported mainly by the exterior body 1 and absorbs body fluids. The longitudinal dimension of the pants-type absorbent article 50 when unfolded as shown in Fig. 2 is, for example, in the range of 600 mm to 1000 mm, and the width dimension is, for example, in the range of 450 mm to 900 mm. In addition, the width dimension of the crotch portion 4 when unfolded, which will be described later, is, for example, in the range of 90 mm to 150 mm, or in the range of 90 mm to 110 mm.

The pants-type absorbent article 50 having the unfolded dimensions described above can be made into pants-type absorbent articles 50 without gathers in various sizes, such as S size, M size, and L size, after arranging elastic stretchable members in predetermined areas as necessary. Furthermore, in order to alleviate the cramped feeling in the crotch area of the wearer, even if the unfolded width direction dimension of the crotch area 4 is narrowed as described above, the outer shape of the pants-type absorbent article 50 can be made into a boxer shorts type that covers the legs, and leakage can be suppressed by eliminating the gap between the absorbent body 51 and the legs.

The pants-type absorbent article 50 of this embodiment includes an exterior body 1 that forms a boxer-short-type outer shape, and an absorbent body 51 that is supported on the skin-side surface of the exterior body 1 and has a generally belt-like shape in the front-to-rear direction that covers the wearer's crotch region from the front and rear. The exterior body 1 includes a ventral side portion 2 that mainly contacts the wearer's abdomen, a back side portion 3 that mainly contacts the wearer's back, and a crotch portion 4 that is located between the ventral side portion 2 and the back side portion 3 and mainly contacts the wearer's crotch region. The exterior body 1 supports the absorbent body 51 mainly on the skin-side surface of the crotch portion 4, and is arranged so that a part or all of the absorbent body 51 overlaps the crotch portion 4. The absorbent body 51 absorbs and retains the wearer's bodily fluids.

<Exterior body>
As shown in Figs. 1 and 2, the exterior body 1 of this embodiment has an abdominal side portion 2 and a back side portion 3 that are substantially symmetrical about a virtual center line extending in the width direction at the center of the longitudinal direction of the crotch portion 4, and the absorbent body 51 is also disposed substantially symmetrically with respect to the virtual center line. The absorbent body 51 is folded in half about the virtual center line so that it is on the inside, and a waist opening 9A and a pair of leg openings 9B are formed by side seal parts 80 that join both side edges in the width direction of the abdominal side portion 2 and the back side portion 3, respectively. In addition, the waist opening 9A is provided with a waist gather 7 in the circumferential direction, which gives the pants-type absorbent article 50 an appropriate feeling of tightness. An elastic stretch member is disposed in the waist gather 7, and the elastic stretch member may be, for example, a thread-like, string-like, or band-like member made of natural rubber, synthetic rubber, polyurethane, or the like. The number of elastic stretch members is not particularly limited, but is, for example, 3 to 8. By setting the number of members to be disposed within the above-mentioned range, an appropriate tightening can be obtained.

In the pants-type absorbent article 50 of this embodiment, although the waist opening 9A has waist gathers 7, there is no need to provide elastic stretchable members around the leg openings 9B, and the waist gathers 7 stretch when worn so that the gathers are not noticeable, so that the pants-type absorbent article 50 has almost no gathers on its outer surface and can have an appearance almost the same as that of cloth underwear. In addition, since at least the abdominal side portion 2 and the dorsal side portion 3 use a composite sheet 8 described later, which contains a resin stretchable film 6, even if a relatively narrow side seal portion 80 is formed, the side seal portion 80 has a bonding strength that does not cause problems in use, and in this respect, the appearance of the pants-type absorbent article 50 can be made closer to that of cloth underwear.

(Composite sheet)
A composite sheet 8 is used as the exterior body 1 in the abdominal portion 2 and the back portion 3. By using the composite sheet 8, the appearance of the pants-type absorbent article 50 can be made closer to that of, for example, cloth underwear by reducing gathers on the surface as shown in FIG. 1. In particular, if there are many gathers on the surface, even if a jacket is put on, the shape of the gathers will appear on the surface of the jacket, so that there is a risk that others will notice that the pants-type absorbent article 50 is being worn. In contrast, in this embodiment, the amount of gathers on the surface can be greatly reduced by using the composite sheet 8. Therefore, the possibility that others will notice that the pants-type absorbent article 50 is being worn is greatly reduced. Furthermore, since the composite sheet 8 arranged on the abdominal portion 2 and the back portion 3 has good breathability, the pants-type absorbent article 50 itself has excellent breathability, and stuffiness is very unlikely to occur even when worn for a long time, and a good wearing feeling is obtained.

The composite sheet 8 of this embodiment includes two nonwoven fabrics 5, an elastic film 6 interposed between the two nonwoven fabrics 5, and a plurality of joints 70 interposed between the nonwoven fabrics 5 and the elastic film 6, spaced apart from each other in the planar direction, and integrating the nonwoven fabrics 5 and the elastic film 6. The joints 70 are the portions where the nonwoven fabrics 5 and the elastic film 6 are bonded. In this specification, the integration of the nonwoven fabrics 5 and the elastic film 6 means that the nonwoven fabrics 5 and the elastic film 6 are bonded to each other, and this adhesion is maintained at least until the pants-type absorbent article 50 is consumed. The joints 70 have a predetermined planar shape, which will be described later. In addition, it is preferable to use a method such as heat fusion or ultrasonic bonding to integrate the nonwoven fabrics 5 and the elastic film 6. By using these methods, the joints 70 having a predetermined planar shape can be easily formed. The integration method will also be described later.

On the other hand, the crotch portion 4 may be made of a composite sheet 8 similar to the abdominal portion 2 and the back portion 3, or may be made of a nonwoven fabric as in the past. When a nonwoven fabric is used as the exterior body of the crotch portion 4, it is preferable to use a laminate of two or more layers of nonwoven fabric as in the past exterior bodies. The laminate of two or more layers is a laminate of an exterior nonwoven fabric sheet, an interior nonwoven fabric sheet, and an auxiliary nonwoven fabric sheet (all not shown), and each of them is a nonwoven fabric such as a thermal bonded nonwoven fabric, an air-through nonwoven fabric, or a spunbonded nonwoven fabric, preferably a spunbonded nonwoven fabric, which is made of a thermoplastic resin such as polypropylene, polyester, or polyethylene. When these nonwoven fabrics are used, the basis weight is, for example, in the range of 10 g/m ² to 40 g/m ² .

The composite sheet 8 is not limited to this embodiment, and may be an integrated product formed by bonding portions 70 of a laminate of three or more sheets of nonwoven fabric 5 and two or more sheets of stretchable film 6 arranged between each of the nonwoven fabrics 15. Examples of the three-dimensional shape of the composite sheet 8 include a three-dimensional shape having a layered shape extending in one direction in cross section and a flat surface, and a three-dimensional shape having a wavy shape extending in one direction in cross section and having regular irregularities on the surface. The latter three-dimensional shape is preferred from the viewpoints of texture, feel, cushioning, etc.

(Air flow resistance value)
The composite sheet 8 has an airflow resistance value in the range of 0.01 kPa·s/m to 0.5 kPa·s/m, preferably 0.05 kPa·s/m to 0.35 kPa·s/m, measured after stretching 250% in the stretch direction. When the composite sheet 8 has the above-mentioned airflow resistance value, the composite sheet 8 constituting the abdominal side portion 2 and the back side portion 3 maintains good air permeability even when the absorbent body 51 is fixed to the skin-side surface of the crotch portion 4. If the airflow resistance value is less than 0.01 kPa·s/m, the heat retention of the pants-type absorbent article 50 tends to decrease and the wearing comfort tends to decrease. If the airflow resistance value exceeds 0.5 kPa·s/m, the air permeability of the pants-type absorbent article 50 tends to decrease and the pants-type absorbent article 50 tends to become stuffy when worn.

(Elongation in the stretch direction)
The composite sheet 8 has an elongation percentage in the stretch direction in the range of, for example, 150% to 270%, or 160% to 260%. Here, the elongation percentage in the stretch direction is the ratio of the length increased by stretching to the natural length in a non-stretched state. The elongation percentage can be measured, for example, using an autograph manufactured by Shimadzu Corporation. By having the elongation percentage in the stretch direction of the composite sheet 8 in the above-mentioned range, a pants-type absorbent article 50 is obtained that is easy for the wearer to put on and take off, has a comfortable fit with appropriate tightness, and is less likely to slip down, giving a sense of security.

(Stretching load)
The composite sheet 8 has an elongation load when elongated 120% in the stretch direction, for example, in the range of 0.8 N/50 mm to 2.0 N/50 mm, and an elongation load when elongated 150% in the stretch direction, for example, in the range of 2.0 N/50 mm to 3.5 N/50 mm. The elongation rate varies depending on the body type of the wearer, so the elongation loads of 120% and 150% are specified. In this way, the fit does not differ depending on the body type. In addition, the composite sheet 8 has an elongation rate in the stretch direction of 200% to 270%. As a result, it is possible to elongate the pants-type absorbent article 50 by 200% or more compared to the conventional method, so that the pants-type absorbent article 50 is easy to put on and take off for the wearer. Here, the elongation rate in the stretch direction is the ratio of the length increased by the stretch to the natural length in the unstretched state, as when the pants-type absorbent article 50 is stretched 120% in the stretch direction. The elongation load can be measured, for example, using an autograph manufactured by Shimadzu Corporation.

(Elongation at break)
The breaking strength of the composite sheet 8 is, for example, in the range of 210% to 280% in the stretching direction. The breaking elongation is expressed as follows: where L1 is the length of the composite sheet 8 in its natural length in an unstretched state, and L2 is the length of the composite sheet 8 when stretched in the stretching direction and broken. If the breaking elongation is in the above-mentioned range, the pants-type absorbent article 50 is unlikely to be stretched or torn even if it is widely stretched when putting on or taking off. The breaking elongation can be measured, for example, using an autograph manufactured by Shimadzu Corporation.

(Nonwoven fabric)
As the nonwoven fabric 5 constituting the composite sheet 8, any nonwoven fabric conventionally used for the outer casing of pants-type absorbent articles can be used, for example, a thermal bonded nonwoven fabric, an air-through nonwoven fabric, a spunbonded nonwoven fabric, a laminate of two or more of these, etc. The laminate of two or more types is bonded, for example, by a hot melt adhesive, heat welding, ultrasonic welding, etc. In a preferred embodiment, the nonwoven fabric 5 contains fibers made of a thermoplastic resin such as polyethylene, polypropylene, or polyethylene as constituent fibers. When the composite sheet 8 contains a plurality of nonwoven fabrics 5, the nonwoven fabrics 5 may be of different or the same type. From the viewpoint of obtaining a composite sheet 8 having a predetermined air resistance value and an elongation rate in the stretch direction, the basis weight of the nonwoven fabric 5 is, for example, in the range of 15 g/m ² to 40 g/m ² , or in the range of 18 g/m ² to 40 g/m ² .

(Stretchable film)
The elastic film 6 constituting the composite sheet 8 is included in the composite sheet 8 in a state in which it is stretched in the stretch direction (a state in which the elongation rate in the stretch direction is within a predetermined range). The elastic film 6 is not particularly limited as long as it has elasticity, but a film made of a synthetic resin that shows elasticity when made into a film is preferable. Examples of the synthetic resin include polyester-based elastomers, polyolefin-based elastomers, polyurethane-based resins, polyamide-based resins, and alloys of two or more of these. Among these, from the viewpoint of cost and elastic performance, a film containing a polyurethane-based resin is preferable, and a film made of a polyurethane-based resin is more preferable. From the viewpoint of obtaining a composite sheet 8 having a predetermined air resistance value and elongation rate in the stretch direction, the thickness of the elastic film 6 is, for example, in the range of 8 μm to 40 μm, and the elongation rate in the stretch direction of the elastic film 6 is, for example, in the range of 100% to 350%.

(Joint)
The composite sheet 8 is integrated by a plurality of joints 70 having a predetermined shape in plan view. The shape in plan view may have one or more corners derived from a rectangle and one or more partial arcs derived from a circle. More specifically, the joints 70 have a shape in plan view in which arc-shaped convex portions protrude outward from two long sides facing each other in the width direction of a rectangle that is long in one direction, as shown in FIG. 4. This figure has four corners and two partial arcs. The composite sheet 8 integrated by a plurality of joints 70 having such a shape in plan view unexpectedly has a good airflow resistance value, is very breathable, and has appropriate mechanical strength, stretchability, and tightening properties, so that there is no need to provide an elastic stretch member in a conspicuous area such as around the leg openings 9B, and continuous gathers are not formed on the exterior surface, making it very suitable as the outer body 1 of the pants-type absorbent article 50. In contrast, when a composite sheet joined at a joint whose planar shape is a rectangle or a circle is used as an outer body, the physical properties of the composite sheet, such as its air resistance value, are not improved, and a pants-type absorbent article having the same problems as conventional ones is obtained.

The joint 70 of this embodiment is a shape that integrates a square 71 extending perpendicular to the stretch direction Y of the composite sheet 8 with a circle 72, where the intersection of the diagonals of the square 71 and the center of the circle 72 coincide (overlap), and the diameter of the circle 72 is longer than the short side of the square 71 and shorter than the long side. The joint 70 has four corners derived from the square 71 and two partial arc-shaped convex parts derived from the circle 72, one of which protrudes in one direction of the stretch direction Y and the other in the other direction of the stretch direction Y (Figure 4 (a)). The square 71 part of the joint 70 extends in a direction that is approximately perpendicular to the stretch direction Y (the inclination angle with respect to the perpendicular direction is 0°), but is not limited to this, and the extension direction of the square 71 part may be inclined at an angle of, for example, 45°, 90°, 135°, etc. with respect to the perpendicular direction (Figure 4 (b)). Such joints 70 are arranged in a predetermined pattern along the stretch direction of the composite sheet 8. For example, the pattern is a combination of an X array and a Y array as shown in FIG. 4(c). The X arrays and Y arrays are arranged alternately in a direction perpendicular to the stretch direction to form an array pattern. X arrays include X1 arrays and X2 arrays, and Y arrays include Y1 arrays and Y2 arrays. The X1 array and X2 array are arranged with a regular phase shift in the stretch direction, and similarly, the Y1 array and Y2 array are arranged with a regular phase shift in the stretch direction. Each of the X arrays and Y arrays may be used alone or in combination of two or more types as shown in FIG. 4(c).

In FIG. 4, an example of each dimension of the joint 70 is shown. The dimension (length in the stretch direction) of the rectangular 71 portion of the joint 70, indicated by the symbol "A", is, for example, in the range of 0.2 mm to 0.4 mm when stretched 250% in the stretch direction Y, the dimension of the joint 70 in the direction approximately perpendicular to the stretch direction Y, indicated by the symbol "B", is, for example, in the range of 0.8 mm to 2.0 mm, and the diameter of the circle 41 of the joint 70, indicated by the symbol "C", is, for example, in the range of 0.3 mm to 0.8 mm.

In FIG. 4C, the shortest distance D1 in the stretching direction between a joint 70 having an inclination angle of 0 degrees in the stretching direction in the arrays X1 and X2 and a joint 70 adjacent to the aforementioned joint 70 having an inclination angle of 90 degrees in the stretching direction is, for example, 1.0 mm to 3.0 mm when the composite sheet 8 is stretched 250% in the stretching direction Y. In addition, in the arrays Y1 and Y2, the shortest distance D1 in the stretching direction between a joint 70 having an inclination angle of 135 degrees in the stretching direction in the arrays Y1 and Y2 and a joint 70 adjacent to the aforementioned joint 70 having an inclination angle of 90 degrees in the stretching direction in the arrays Y1 and Y2 is, for example, 1.0 mm to 3.0 mm when the composite sheet 8 is stretched 250% in the stretching direction Y. The shortest distance D2 in the stretching direction between a joint 70 having an inclination angle of 45° is, for example, in the range of 2.0 mm or more and 5.0 mm or less when the composite sheet 8 is stretched 250% in the stretching direction Y, and the shortest distance D3 in the direction perpendicular to the stretching direction between a joint 70 having an inclination angle of 90 degrees in the stretching direction X1 and a joint 70 having an inclination angle of 135° in the stretching direction Y1 in the arrangement X1, Y1 is, for example, in the range of 1.0 mm or more and 3.0 mm or less.
By setting the dimensions of the joints 70 and the shortest distance between the joints within the above-mentioned ranges, the breathability of the composite sheet 8 is further improved and the decrease in durability of the stretchable film 6 is mitigated.

The composite sheet 8 has an adhesive area ratio of the joints 70 in the range of, for example, 4% to 18%. Here, the adhesive area ratio is the ratio of the total area of the joints 70 present in a unit area of the composite sheet 8 expressed as a percentage. If the adhesive area ratio is less than 4%, the breathability of the composite sheet 8 tends to decrease. On the other hand, if the adhesive area ratio exceeds 18%, the strength of the composite sheet 8 tends to decrease.

The composite sheet 8 can be produced, for example, by the manufacturing method shown in FIG. 5. FIG. 5 is a diagram that shows a schematic diagram of the manufacturing method of the composite sheet 8. FIG. 5(a) is a schematic side view showing all steps of the manufacturing method of the composite sheet 8. FIG. 5(b) is a schematic cross-sectional view showing an enlarged view of the third step (bonding step). The manufacturing method shown in FIG. 5 uses ultrasonic bonding, and includes the first to third steps in this order.

In the first step, the elastic film 6 wrapped around the feed roller 51 is conveyed while being subjected to a predetermined tension. The elastic film 6 is conveyed while being stretched in the conveying direction by the predetermined tension. The predetermined tension is a tension that stretches the elastic film 6 by 200% or more, more preferably by 250±30%.

In the second step following the first step, each nonwoven fabric 5 wound around two feed rollers 52 is laminated above and below the stretchable film 6 that is being transported in a stretched state, to obtain a pre-integrated laminate.

In the third step following the second step, the pre-integrated laminate obtained in the second step is passed through the pressing portion (hereinafter also referred to as the "nip portion") of the first and second joining rollers 53 and 54 to integrate the laminate so as to form a predetermined joint 70, thereby obtaining a composite sheet 8. The first joining roller 53 has a plurality of recesses 55 extending in the width direction and having a predetermined dimension and a predetermined internal space shape provided at a predetermined interval in the circumferential direction on its peripheral surface. The second joining roller 54 has a plurality of protrusions 56 extending in the width direction and having a predetermined dimension and a predetermined three-dimensional shape (a three-dimensional shape whose tip portion can be inserted into the recess 55 with the laminate interposed therebetween) provided at a predetermined interval in the circumferential direction on its peripheral surface. The first and second joining rollers 53 and 54 are engaged with each other so that the tip portion of the protrusion 56 can be inserted into the recess 55, and are pressed together with a predetermined pressure. In the nip portion of the first and second joining rollers 53 and 54, a seal line that is substantially continuous in the width direction of the roller periphery is formed at intervals of 0.5 mm to 2.0 mm in the stretching direction. Either or both of the first and second joining rollers 53 and 54 is equipped with an ultrasonic generator or a heater, and is configured to be able to apply ultrasonic waves or heat the inner wall surface of the recessed portion 55 or at least the tip portion of the protruding portion 56.

In the third step, the unintegrated laminate obtained in the second step is passed under pressure through the nip between the first and second bonding rollers 53 and 54, and ultrasonic waves or heat are applied to the seal line, which is the contact point between the inner wall surface of the recess 55 and the tip of the protrusion 56, to form multiple bonding parts 70 having a predetermined planar shape, and the nonwoven fabric 5 and the stretchable film 6 are integrated by the multiple bonding parts 70, resulting in a composite sheet 8 with few wrinkles on the surface and a smooth feel. That is, multiple bonding parts 70 having the planar shape shown in FIG. 4 are formed at the predetermined intervals shown in FIG. 4, and a composite sheet 8 in which the nonwoven fabric 5 and the stretchable film 6 are integrated is obtained.

<Absorbent>
3 includes a liquid-permeable top sheet 10 that is mainly supported on the skin-side surface of the crotch portion 4 and is located on the skin side, a liquid-impermeable back sheet 30 that is arranged opposite the top sheet 10 and is located on the non-skin side, a second sheet 60 that is arranged between the top sheet 10 and the absorbent sheet 20, the absorbent sheet 20 that is arranged between the second sheet 60 and the back sheet 30, and a pair of three-dimensional gathers 40 that are provided on the skin-side surface of the top sheet 10. The absorbent body 51 may be provided detachably mainly on the skin-side surface of the crotch portion 4 of the exterior body 1. The absorbent sheet 20 is constructed by stacking, in order from the wearer's skin side, a first hydrophilic nonwoven fabric 21, a first superabsorbent polymer layer (hereinafter also referred to as "SAP layer") 23, a second hydrophilic nonwoven fabric 21, a second SAP layer 23, and a pulp sheet 22 (Figure 6), and an embossed groove 15 is formed in a predetermined shape when viewed in a planar view, extending from the skin side surface of the absorbent sheet 20 to the surface of the pulp sheet 22 or its vicinity.

According to the absorbent body 51 shown in FIG. 3 of this embodiment, firstly, by providing multiple thin SAP layers 23 while maintaining the advantage of the thinness of the absorbent sheet 20, gel blocking is prevented in each layer, improving the body fluid absorption capacity, and preventing the hardness caused by the superabsorbent polymer 12 from appearing, improving the wearing comfort of the absorbent body 51; secondly, by arranging the pulp sheet 22 on the side closest to the skin of the absorbent sheet 20, leakage of body fluids and liquid return are prevented; and thirdly, by providing a predetermined embossed groove 15 extending from the skin side surface of the absorbent sheet 20 to the skin side surface of the pulp sheet 22, the body fluid diffusion of the entire absorbent sheet 20 is improved, and the absorption speed and absorption rate are maintained at a high level even after multiple body fluid absorptions.

The absorbent body 51 has a top sheet 10, an absorbent sheet 20, and a back sheet 30 as basic constituent units, and various known modifications can be made, such as the provision of three-dimensional gathers 40 as described above, and the placement of a second sheet 60 between the top sheet 10 and the absorbent sheet 20. Below, the constituent members of the absorbent body 51 of this embodiment will be described in more detail in the order of the top sheet 10, the second sheet 60, the absorbent sheet 20, the back sheet 30, and the three-dimensional gathers 40.

(Top sheet)
The top sheet 10 is a liquid-permeable sheet-like substrate that quickly passes bodily fluids toward the absorbent sheet 20 and diffuses the bodily fluids in the surface direction of the absorbent sheet 20. The top sheet 10 is preferably a substrate that is soft to the touch and does not irritate the skin so that it may be directly in contact with the wearer's skin. Examples of the substrate include hydrophilic sheets, composite nonwoven fabrics that are laminates of the same or different hydrophilic sheets, open-ended films such as open-ended polyethylene films, and foamed films such as polyethylene foam and urethane foam. Examples of hydrophilic sheets include air-through nonwoven fabrics, thermal bond nonwoven fabrics, spunlace nonwoven fabrics, spunbond nonwoven fabrics, and the like, which are made using synthetic fibers made of synthetic resins such as polypropylene and polyethylene, regenerated fibers such as rayon, and natural fibers such as cotton. Among these, each nonwoven fabric is preferable.

The top sheet 10 may be embossed or perforated on its surface in order to improve liquid permeability. The top sheet 10 may contain one or more of lotions, antioxidants, anti-inflammatory components, pH adjusters, antibacterial agents, moisturizers, etc. in order to reduce irritation to the skin. The basis weight of the top sheet 10 is, for example, in the range of 15 g/ ^m2 to 40 g/ ^m2 in terms of strength, processability, and liquid return. The shape of the top sheet 10 is not particularly limited, and may be any shape that covers a part or all of the absorbent sheet 20, which is necessary to guide bodily fluids to the absorbent sheet 20 without leakage.

(Second seat)
The second sheet 60 is disposed on the non-skin side of the top sheet 10, more specifically, between the top sheet 10 and the absorbent sheet 20. Disposing the second sheet 60 increases cushioning properties, improves fit and wearing comfort, and enables bodily fluids that have permeated the top sheet 10 to be diffused almost uniformly throughout the absorbent sheet 20.

The base material of the second sheet 60 is, for example, a bulky nonwoven fabric that has a faster permeation rate of bodily fluids than the top sheet 10 and quickly diffuses bodily fluids into the absorbent sheet 20. Air-through nonwoven fabrics, spunbond nonwoven fabrics, etc. are preferred as the nonwoven fabric. The thickness of the second sheet 60 is, for example, in the range of 0.1 mm to 4 mm, and the basis weight is, for example, in the range of 20 g/m ² to 60 g/m ² , or in the range of 22 g/m ² to 37 g/m ^2. If the thickness is less than 0.1 mm, or the basis weight is less than 20 g/m ² or more than 60 g/m ² , bodily fluids do not sufficiently diffuse over the entire skin-side surface of the absorbent sheet 20, and the wearing comfort of the absorbent body 51 tends to decrease. In addition, the shape of the second sheet 60 is not particularly limited, but in a preferred embodiment, it is a shape that can completely cover the surface of the absorbent sheet 20.

(Absorbent sheet)
The absorbent sheet 20 has a longitudinal dimension (maximum length) in the range of, for example, 100 mm to 800 mm, 150 mm to 500 mm, or 270 mm to 500 mm. The widthwise dimension (maximum width) of the absorbent sheet 20 is, for example, in the range of 50 mm to 105 mm. When the planar shape of the absorbent sheet 20 is an hourglass shape, the longitudinal dimension is, for example, in the range of 180 mm to 800 mm, the widthwise dimensions of the region supported by the ventral side portion 2 and the dorsal side portion 3 of the exterior body 1 are both, for example, in the range of 60 mm to 400 mm, and the widthwise dimension of the region supported by the crotch portion 4 of the exterior body 1 is, for example, in the range of 90 mm to 250 mm. Examples of the planar shape of the absorbent sheet 20 include an hourglass shape, an I-shape, a rectangle, a rounded rectangle with rounded corners, an oval, and the like.

The absorbent sheet 20 includes a hydrophilic nonwoven fabric 21 that diffuses bodily fluids in the surface direction and thickness direction, and a superabsorbent polymer layer 23 that absorbs bodily fluids and is supported by the hydrophilic nonwoven fabric 21. The absorbent sheet 20 includes a pulp sheet 22 on the most non-skin side that temporarily stores bodily fluids when the bodily fluids are discharged, and does not include absorbent fibers. Specific examples of the absorbent sheet 20 of this embodiment include the absorbent sheet precursor 20A shown in FIG. 6 and the absorbent sheet precursor 25A shown in FIG. 7. In this embodiment, an embossed groove 15 is formed, which is a groove portion that extends from the skin side surface of the absorbent sheet precursors 20A and 25A to the skin side surface of the pulp sheet 22 or its vicinity, but this is not necessary. The embossed groove 15 will be described later.

The absorbent sheet precursor 20A shown in FIG. 6 is an absorbent sheet formed by stacking a first hydrophilic nonwoven fabric 21, a first SAP layer 23, a second hydrophilic nonwoven fabric 21, a second SAP layer 23, and a pulp sheet 22 in order from the wearer's skin side. The absorbent sheet precursor 25A shown in FIG. 7 is an absorbent sheet formed by stacking a first hydrophilic nonwoven fabric 21, a first SAP layer 23, a second hydrophilic nonwoven fabric 21, a second SAP layer 23, a third hydrophilic nonwoven fabric 21, a third SAP layer 23, and a pulp sheet 22 in order from the wearer's skin side. The thickness of the absorbent sheet 20 is, for example, in the range of 0.5 mm to 5 mm. The superabsorbent polymer 12 is fixed in the first, second, and third SAP layers 23, for example, by a hot melt adhesive.

(hydrophilic nonwoven fabric)
The first, second, and third hydrophilic nonwoven fabrics 21, for example, diffuse body fluids in the surface direction and thickness direction of the absorbent sheet 20. As the hydrophilic nonwoven fabric 21, any hydrophilic nonwoven fabric having excellent diffusibility of body fluids can be used without any particular limitation, and examples thereof include air-through nonwoven fabrics and spunbond nonwoven fabrics containing one or more types of fibers made of synthetic resins such as polyethylene, polypropylene, and polyester. Among these, from the viewpoint of making the absorbent sheet 20 or the absorbent sheets 20A and 25A thinner, for example, spunbond nonwoven fabrics can be used. The basis weight of the hydrophilic nonwoven fabric 21 is, for example, in the range of 10 g/m ² or more and 40 g/m ² or less. The thickness of the hydrophilic nonwoven fabric 21 is, for example, in the range of 0.05 mm or more and 0.3 mm or less. The first, second, and third hydrophilic nonwoven fabrics 21 can be made of the same or different hydrophilic nonwoven fabrics.

(Pulp sheet)
The pulp sheet 22 is located on the closest side to the skin of the absorbent sheet 20 or absorbent sheet 20A, 25A, and supports, for example, the second or third SAP layer 23, and when bodily fluid is discharged, temporarily stores and holds the bodily fluid before the superabsorbent polymer 12 starts absorbing the bodily fluid, thereby preventing leakage, return of the bodily fluid, etc. Since the pulp sheet 22 holds the bodily fluid faster than the superabsorbent polymer 12 absorbs the bodily fluid, when the superabsorbent polymer 12 starts absorbing the bodily fluid, the bodily fluid held in the pulp sheet 22 is absorbed by the superabsorbent polymer 12. The pulp sheet 22 is not particularly limited as long as it is a sheet containing pulp fibers (cellulose fibers), and examples thereof include crepe paper made of cellulose fibers, crepe paper containing a wet strength agent, tissue, etc. In order to fully exert the above-mentioned functions of the pulp sheet 22, the basis weight of the pulp sheet 22 is, for example, in the range of 10 g/ ^m2 or more and 30 g/ ^m2 or more, and the thickness is, for example, in the range of 0.05 mm or more and 0.2 mm or less.

(Superabsorbent polymer)
The superabsorbent polymer 12 used in each of the first, second and third SAP layers 23 is not particularly limited as long as it can absorb body fluids and prevent backflow, and examples of the superabsorbent polymer 12 include polyacrylates, polyaspartates, (starch-acrylic acid) graft copolymers, (acrylic acid-vinyl alcohol) copolymers, (isobutylene-maleic anhydride) copolymers and saponification products thereof. Among these, from the viewpoint of the absorption amount per weight, polyacrylates are preferred, alkali metal polyacrylates are more preferred, and sodium polyacrylate is even more preferred. The superabsorbent polymer 12 may be used alone or in combination of two or more types.

The superabsorbent polymer 12 is used in the form of particles, fibers, etc., but is preferably used in the form of particles from the viewpoint of ease of handling, etc. In this case, by avoiding the use of a fine powder of superabsorbent polymer 12 that has poor fluidity as a powder and using a superabsorbent polymer 12 having a medium particle size, it is possible to improve the basic absorption performance and reduce the rough feel caused by the absorbent sheet 20 hardening after absorbing body fluids. The medium particle size of the superabsorbent polymer 12 is, for example, in the range of 50 μm to 600 μm or in the range of 100 μm to 500 μm.

From the viewpoint of preventing gel blocking, the basis weight of the superabsorbent polymer 12 in the first, second, and third SAP layers 23 is, for example, in the range of 150 g/m ² to 800 g/m ² or in the range of 200 g/m ² to 700 g/m ^2. By setting the basis weight of the SAP within the above-mentioned numerical range, gel blocking in the first, second, and third SAP layers 23 can be prevented and the absorbent sheet 20 can be made to have a soft feel. In addition, the thickness of the first, second, and third SAP layers 23 is, for example, in the range of 0.5 mm to 10.0 mm or in the range of 0.5 mm to 6.0 mm. The basis weight and thickness of the first, second, and third SAP layers 23 may be the same or different.

The hot melt adhesive used to fix the superabsorbent polymer 12 in the first, second, and third SAP layers 23 may be any hot melt adhesive having a melting point of 100° C. or higher and 180° C. or lower, and examples of such hot melt adhesives include synthetic rubber hot melt adhesives such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers, and olefin hot melt adhesives such as ethylene-vinyl acetate copolymers. Known methods for applying the hot melt adhesive include a curtain coat method or a spiral method in which the hot melt adhesive in a molten state is applied from a nozzle in a non-contact manner, and a slot method in which the hot melt adhesive is applied in a contact manner. The content of the hot melt adhesive is, for example, in the range of 10 g/m ² or less from the viewpoint of not impairing the absorbency of the superabsorbent polymer 12 and the feel on the skin when worn.

<Method for producing absorbent sheet precursor>
The absorbent sheet precursor 20A can be manufactured according to a known method. For example, the manufacturing method includes a first step of applying a hot melt adhesive to the non-skin side surface of the first hydrophilic nonwoven fabric 21, and further spraying a predetermined amount of superabsorbent polymer 12 to form a first SAP layer 23, a second step of superposing a second hydrophilic nonwoven fabric 21 on the first SAP layer 23 (non-skin side surface) and forming a second SAP layer 23 on the non-skin side surface of the second hydrophilic nonwoven fabric in the same manner as in the first step, and a third step of superposing a pulp sheet 22 on the second SAP layer 23 (non-skin side surface) to obtain the absorbent sheet precursor 20A. The absorbent sheet precursor 20A may be subjected to a pressurizing treatment or a pressurizing and heating treatment as necessary. The absorbent sheet 20 used in this embodiment is obtained by subjecting the absorbent sheet precursor 20A to an embossing process. The absorbent sheet precursor 25A can be manufactured in the same manner.

(embossed groove)
The skin side surface of the absorbent sheet 20 may be provided with an embossed groove 15, which is a groove portion extending from the skin side surface to the skin side surface of the pulp sheet 22 or its vicinity, and includes a first embossed groove 16 extending in the longitudinal direction through the width center of the skin side surface, and a second embossed groove 17 including a plurality of embossed grooves intersecting or contacting the first embossed groove 16 at an acute angle. A specific example of such an embossed groove 15 is the embossed groove 15 shown in Fig. 8. The embossed groove 15 shown in Fig. 8 includes a first embossed groove 16 extending in the longitudinal direction through the width center of the skin side surface of the absorbent sheet 20, and a second embossed groove 17 that is provided in an X-shape in a plan view on the skin side surface of the absorbent sheet 20, with the intersection of the X-shape being located on the first embossed groove 16. In the _X1 - _X1 cross section of Fig. 8, only the first embossed groove 16 can be seen as shown in Fig. 9(a), and in the _X2 - _X2 cross section of Fig. 8, it can be seen that the second embossed groove 17 is disposed on both sides in the width direction of the first embossed groove 16 as shown in Fig. 9(b). The embossed groove 15 can be formed on the skin-side surface of the absorbent sheet 20 by utilizing, for example, heat embossing, ultrasonic embossing, high-frequency embossing, etc.

In this embodiment, the width dimension of the opening of the first embossed groove 16 (hereinafter also simply referred to as the "width dimension of the first embossed groove 16") is formed to be slightly larger than or the same width as the width dimension of the opening of the second embossed groove 17 (hereinafter also simply referred to as the "width dimension of the second embossed groove 17"); for example, the width dimension of the first embossed groove 16 is in the range of 3 mm to 8 mm, and the width dimension of the second embossed groove 17 is in the range of 3 mm to 8 mm.

In addition, in this embodiment, multiple second embossed grooves 17 are arranged in the longitudinal direction of the absorbent sheet. That is, three X-shaped second embossed grooves 17 are arranged in the longitudinal direction with the intersections of the Xs on a line (first embossed groove 16). The number of second embossed grooves 17 is not limited to this embodiment, and may be one or more. In a preferred embodiment, the distance V (FIG. 5) between one second embossed groove 17 and another adjacent second embossed groove 17 may be 0 mm, and when they are separated from each other, it is, for example, in the range of 0 mm to 20 mm. When V is greater than 20 mm, the second embossed grooves 17 are too far apart in the longitudinal direction, and the improvement in bodily fluid diffusion tends to be insufficient.

In another preferred embodiment of the present invention, a virtual figure surrounded by two lines A extending in the width direction from both longitudinal ends of the first embossed portion 16 and two lines B extending in the longitudinal direction from the outermost point in the width direction on both widthwise sides of the second embossed portion 17 is a figure with a minimum area that contains the entire embossed groove 15 and is similar to the planar shape of the absorbent sheet. At this time, the distance between the edge of the virtual figure and the edge of the absorbent sheet 20 is shown in FIG. 8 as L1, L2, which are the lengthwise distances, and W1, W2, which are the widthwise distances, but these are all the same and may be 0 mm (when the virtual figure and the planar shape of the absorbent sheet match), and when there is a distance, it is, for example, in the range of 0 mm to 3 mm. According to this embodiment, the discharged body fluid is smoothly absorbed into the absorbent sheet 20 through the embossed portion 15. If the distance between the edge of the virtual figure and the edge of the absorbent sheet exceeds 3 mm, some of the body fluid diffused from the embossed portion 15 will not be instantly absorbed by the absorbent sheet 20, and will tend to overflow onto the skin-facing surface and cause leakage. Note that this is not limited to the present embodiment, and L1, L2, W1, and W2 may each be varied independently within a range of, for example, 0 mm or more and 3 mm or less.

In another preferred embodiment, the minimum distance W3 (FIG. 5) in the width direction of the absorbent sheet 20 from one end of the first embossed groove 16 in the width direction to the tip of the second embossed groove 17 in the same width direction is, for example, in the range of 3 mm to 8 mm. According to this embodiment, the effect of improving the bodily fluid diffusion by forming the embossed groove 15 is stably exhibited. If the minimum distance W3 is less than 3 mm, the bodily fluid diffusion tends to be insufficient. If the minimum distance W3 exceeds 8 mm, a thick flow of bodily fluids tends to occur, which may cause leakage.

In yet another preferred embodiment, in the second embossed groove 17 shown in FIG. 8, the angles α, β, and γ (FIG. 8) formed by the "X" of the X-shaped shape in plan view of the second embossed groove 17 facing the widthwise edge of the absorbent sheet are 50° or more and 90° or less. According to this embodiment, the effect of improving the bodily fluid diffusion by forming the second embossed groove 17 is stably exhibited. If the angles α, β, and γ are less than 50° or more than 90°, the superabsorbent polymer 12 that has absorbed and swelled with bodily fluids tends to cause gel blocking, filling the second embossed groove 17, and reducing the bodily fluid diffusion. Note that when there are multiple second embossed grooves 17 as shown in FIG. 8, the angles α, β, and γ may be the same or different.

(Career sheet)
In this embodiment, the absorbent sheet 20 may be wrapped in a carrier sheet (not shown). The carrier sheet is a hydrophilic sheet, and wraps the absorbent sheet 20 entirely or partially. For example, the absorbent sheet 20 is placed in the widthwise center of the carrier sheet, and the carrier sheet and the absorbent sheet 20 are bonded together with a hot melt adhesive or the like as necessary, and then both ends of the carrier sheet in the widthwise direction are overlapped with the skin side of the absorbent sheet 20 and bonded together with a hot melt adhesive or the like as necessary, to obtain the absorbent sheet 20 folded in a C shape with the carrier sheet. As the carrier sheet, any hydrophilic sheet commonly used in this field can be used, and examples thereof include hydrophilic nonwoven fabrics such as thermal bond nonwoven fabrics, spun bond nonwoven fabrics, air laid nonwoven fabrics, air through nonwoven fabrics, and pulp-containing nonwoven fabrics, tissue paper, absorbent paper, and the like. Among hydrophilic nonwoven fabrics, hydrophilic nonwoven fabrics such as thermal bonded nonwoven fabrics, spunbonded nonwoven fabrics, air-through nonwoven fabrics, and pulp-containing nonwoven fabrics are more preferred, and air-through nonwoven fabrics, pulp-containing nonwoven fabrics, spunbonded nonwoven fabrics, etc. are even more preferred. The thickness of the carrier sheet is, for example, in the range of 0.10 mm to 0.25 mm, and the basis weight is, for example, in the range of 5 g/ ^m2 to 40 g/ ^m2 .

(Back seat)
The back sheet 30 may be formed using a liquid-impermeable substrate that prevents the body fluid held by the absorbent sheet 20 from wetting the wearer's clothing, and examples of the substrate include a resin film and a composite sheet that is a laminate of a resin film and a nonwoven fabric. The nonwoven fabric used in the composite sheet is not particularly limited in its manufacturing method, and examples thereof include single-layer nonwoven fabrics such as spunbond nonwoven fabric and meltblown nonwoven fabric, composite nonwoven fabrics such as spunbond nonwoven fabric/meltblown nonwoven fabric laminates, and composite materials thereof. Examples of the resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, and composite films of polyethylene and polypropylene.

The basis weight of the back sheet 30 is, for example, in the range of 15 g/ ^m2 to 60 g/ ^m2 in terms of strength and processability. In order to prevent stuffiness during wear, it is preferable that the back sheet 30 is breathable. In order to provide the back sheet 30 with breathability, for example, a filler may be blended into the resin film of the base material, or the back sheet 30 may be embossed. An example of the filler is calcium carbonate, and the blending method may be any known method without any restrictions.

(3D gathers)
The three-dimensional gathers 40 are fixed to the skin side of the top sheet 10 near both ends in the width direction of the absorbent body 51 along the longitudinal direction of the absorbent body 51 in order to prevent, for example, lateral leakage of bodily fluids excreted by the wearer of the absorbent body 51. The three-dimensional gathers 40 include an elastic stretch member 40a and a water-repellent and/or waterproof sheet member 40b.

The elastic stretch member 40a is disposed in the longitudinal direction near the free end (other end) of the sheet member 40b, imparting uprightness to the free end, and allowing the free end of the sheet member 40b and its neighboring area to be deformed to fit the wearer's body shape. In this embodiment, the sheet member 40b has one widthwise end (fixed end) fixed near both widthwise ends of the skin side of the back sheet 30, a middle part in the widthwise direction fixed near both widthwise ends of the skin side of the top sheet 10, and the other widthwise end being a free end having uprightness. The fixing position of the fixed end (one widthwise end) of the sheet member 40b is not limited to this embodiment, and may be, for example, the non-skin side of the back sheet 30, near both widthwise ends of the skin side or non-skin side of the joint of all or part of each edge of the top sheet 10 and the back sheet 30 with the absorbent sheet 20 stored therein, near both widthwise ends of the skin side of the top sheet 10, etc.

The sheet member 40b is a water-repellent and/or waterproof sheet, and is made of, for example, a nonwoven fabric. As the nonwoven fabric for the first sheet member, any water-repellent and/or waterproof (liquid-impermeable) nonwoven fabric formed of hydrophobic fibers can be used without any particular limitation, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, and composite nonwoven fabric (SMS nonwoven fabric) which is a spunbond nonwoven fabric/meltblown nonwoven fabric/spunbond nonwoven fabric laminate. The basis weight of the sheet member 40b is, for example, in the range of 13 g/m ² or more and 20 g/m ² or less. As the elastically stretchable member 40a, for example, a thread-like, string-like, or strip-like material made of natural rubber, synthetic rubber, polyurethane, or the like can be appropriately used.

<Method of manufacturing absorbent body>
The absorbent body 51 can be manufactured by a known manufacturing method, and examples of such manufacturing methods include a process of accommodating the absorbent sheet 20 between the top sheet 10 and the second sheet 60 and the back sheet 30, a process of fixing the edge of the top sheet 10 and the edge of the back sheet 30 partially or entirely around the periphery using a hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing, or the like, and a process of providing the three-dimensional gathers 40 at predetermined positions on the back sheet 30 and the top sheet 10. The absorbent body 51 is appropriately provided with leg gathers, waist gathers, side flaps, and the like as necessary. The absorbent body 51 thus obtained is folded to be manufactured into a product.

<Method of manufacturing pants-type absorbent article>
The pants-type absorbent article 50 can be produced in the same manner as conventional pants-type absorbent articles, except that a composite sheet 8 is used as the exterior body 1 of the abdominal portion 2 and the back portion 3, or the abdominal portion 2, the back portion 3 and the crotch portion 4. For example, the pants-type absorbent body 51 can be obtained by a manufacturing method including the steps of producing the abdominal portion 2 and the back portion 3 with the composite sheet 8, forming the crotch portion 4 with a laminate of conventional nonwoven fabrics, and joining these in the longitudinal direction in a predetermined order to obtain the exterior body 1, fixing the absorbent body 51 to a predetermined position (mainly the crotch portion 4) on the skin-side surface of the exterior body 1, and welding both ends in the width direction of the abdominal portion 2 and the back portion 3 to form a side seal portion 80. The pants-type absorbent body 51 thus obtained is folded in a predetermined order and packed into a bag to be commercialized.

Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that forms incorporating such modifications or improvements can also be included in the technical scope of the present invention.

The following describes this embodiment in more detail with examples.

<Examples 1 to 11 and Comparative Examples 1 to 10>
(Preparation of composite sheet)
A polyurethane stretch film (thickness 20 μm, stretch rate in stretch direction 250%) was placed between two polypropylene spunbond nonwoven fabrics (basis weight 20 g/m 2 ) and integrated with each other to produce a composite sheet, which had the planar shape and arrangement shown in Figure 4 (arrangement X and array Y alternately arranged in a direction perpendicular to the rows) and the dimensions shown in Table 1 (dimensions A, B, C, D1, D2, and D3 shown in Figure ⁴ ), and had the joints of each of the joint arrangement patterns (A) to (F) formed by ultrasonic bonding. Note that in Comparative Examples (D) to (F), composite sheets were produced in the same manner as for the joint arrangement patterns (A) to (C), except that the planar shape of the joints was a circle (joint arrangement pattern (D)) or a rectangle (joint arrangement patterns (E) and (F)).

The composite sheets thus produced were subjected to the following evaluation tests and sensory evaluation. The results are shown in Table 1.
(Breathability evaluation, stretchability evaluation)
The composite sheets having the joint arrangement patterns (A) to (F) were stretched once in the stretch direction by 250% and then released, and the air flow resistance value R (kPa·s/m) was measured using a breathability tester (product name: KES-F8, manufactured by Kato Tech Co., Ltd.) In addition, the elongation load (N/50 mm) was measured at 120% elongation and 150% elongation with a sample width of 50 mm (perpendicular to the stretch direction) using an autograph manufactured by Shimadzu Corporation.

(Evaluation of elasticity, fit, and flexibility of exterior parts)
An absorbent body was produced by using a composite sheet with joint arrangement patterns (A) to (F) as an exterior body, an air-through nonwoven fabric with a basis weight of 30 g/ ^m2 as a top sheet, and a breathable polyethylene film with a basis weight of 32 g/ ^m2 as a back sheet, and an absorbent sheet having the configuration shown in Tables 2 to 4 was placed between the top sheet and the back sheet, and bonded with a hot melt adhesive to the skin side surface of the exterior body, mainly in the crotch area. In addition, waist gathers were bonded to the skin side surface of the exterior body at both ends in the longitudinal direction of the absorbent body, each of which was made of spunbond nonwoven fabric with six urethane rubber threads of 1240 decitex extending in the width direction and stretched to 300%, to produce pants-type absorbent articles of Examples 1 to 11 and Comparative Examples 1 to 10.

Twenty test subjects wore each of the pants-type absorbent articles using the composite sheets of the joint arrangement patterns (A) to (F) of Examples 1 to 11 and Comparative Examples 1 to 10, and conducted a sensory evaluation of the stretchability (ease of wearing), fit, and flexibility of the exterior body (softness of touch and texture). For each sensory evaluation, the subjects were surveyed with two choices between "good" and "bad," and the evaluation was based on the following criteria.
〇: When there are 12 to 20 people who choose "Good" △: When there are 5 to 11 people who choose "Good" ×: When there are no people who choose "Good" or when there are 1 to 4 people who choose "Good"

The following evaluations were carried out on the absorbents shown in Tables 3 and 4 of Examples 1 to 11 and Comparative Examples 1 to 10 before they were attached to an exterior body. The results are shown in Tables 3 and 4.
(Thickness of absorber)
The thickness of each of the absorbent bodies of Examples 1 to 11 and Comparative Examples 1 to 10 was measured at the center thereof using an ABS Digimatic Height Gauge HDS-HC (manufactured by Mitutoyo Corporation).
(Absorption rate 3 times method)
A measuring tool with a weight of 755.6 g and a hole with an inner diameter of 19 mm penetrating vertically in the center of a cylinder with a base area of 16.8 ^cm2 was placed on the center of the absorbent body in the longitudinal and width directions, and 40 ml of saline was dropped from the upper hole. The time was measured from the time the saline came into contact with the absorbent article to the time when the liquid was completely absorbed into the circumference of the center circle of the tool (first time). The same time was then measured after 3 minutes had elapsed (second time), and a third time was measured in the same manner. The total values for the three times are shown in Tables 3 and 4.
(45 degree leak test)
A 45-degree leakage test was conducted to check the temporary absorption of bodily fluids. Two acrylic plates measuring 250 mm x 400 mm x 8 mm were fixed, one horizontally and the other inclined at 45 degrees from the horizontally placed acrylic plate. The absorbent article prepared was attached to the acrylic plate inclined at 45 degrees from the horizontal. 20 mL of saline was poured toward the center of the absorbent body, and if no leakage occurred from the bottom of the absorbent article, it was evaluated as "○", and if leakage occurred, it was evaluated as "×".

From Table 1, it can be seen that the joint arrangement pattern used in the examples gives the resulting composite sheet with a lower air resistance value and excellent breathability, a smaller elongation load and less tightness, and the pants-type absorbent article using the composite sheet as an outer body has good stretchability, fit, and flexibility compared to the joint arrangement pattern used in the comparative examples.
From the results in Table 3, it can be said that the pants-type absorbent articles of Examples 1 to 11 have a high absorption rate of bodily fluids, good 45-degree leakage, no problems with temporary absorption, and are less likely to leak. On the other hand, the pants-type absorbent articles of Comparative Examples 1 to 10 in Table 4 had a slow absorption rate or poor 45-degree leakage, or both.
Therefore, according to this embodiment, it is possible to obtain an absorbent article which is less susceptible to gel blocking, has a high absorption rate, and is also excellent in temporary absorption.

REFERENCE SIGNS LIST 1 Exterior body 2 Abdominal portion 3 Dorsal portion 4 Crotch portion 5 Nonwoven fabric 6 Elastic film 7 Waist gathers 8 Composite sheet 9A Opening around waist 9A
9B Leg openings 10 Top sheet 12 Superabsorbent polymer 15 Embossed groove 16 First embossed groove 17 Second embossed groove 20 Absorbent sheet 20A, 25A Absorbent sheet precursor 21 First, second and third hydrophilic nonwoven fabrics 22 Pulp sheet 23 First, second and third superabsorbent polymer layers (SAP layers)
Reference Signs List 30 Back sheet 40 Three-dimensional gather 40a Elastically stretchable member 40b Sheet member 50 Pants-type absorbent article 51 Absorbent body 60 Second sheet 70 Joint portion 71 Rectangle 72 Circle 80 Side seal portion

Claims (11)

A pants-type absorbent article comprising an exterior body divided into a ventral side portion, a crotch portion, and a back side portion, and an absorbent body that is supported mainly by the crotch portion of the exterior body and absorbs body fluids,
The absorbent body includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent sheet disposed therebetween, the absorbent sheet including a hydrophilic nonwoven fabric that diffuses bodily fluids in a surface direction and a thickness direction, and a highly absorbent polymer layer that absorbs bodily fluids, and a pulp sheet that temporarily retains bodily fluids on the side closest to the wearer's skin,
The exterior body includes a composite sheet including a plurality of nonwoven fabrics, a stretchable film disposed between the nonwoven fabrics, and a plurality of joints spaced apart from each other in a surface direction to integrate the nonwoven fabrics and the stretchable film,
The composite sheet has an air flow resistance value in the range of 0.01 kPa·s/m or more and 0.5 kPa·s/m or less when stretched 250% in the stretch direction,
Each of the joints has a shape in plan view that has corners derived from a rectangle and partial arc portions derived from a circle,
The pants-type absorbent article further has waist gathers, which are arranged circumferentially along a waist opening formed by joining both widthwise ends of the abdominal side portion and both widthwise ends of the back side portion, and which include an elastic stretchable member. The pants-type absorbent article according to claim 1, having a boxer-short appearance. The pants-type absorbent article according to claim 1 or 2, wherein the composite sheet has an elongation rate in the stretch direction of 150% or more and 270% or less. The pants-type absorbent article according to any one of claims 1 to 3, wherein the number of the elastic stretch members is 3 or more and 8 or less. The pants-type absorbent article according to any one of claims 1 to 4, wherein the absorbent sheet is a first absorbent sheet in which the first hydrophilic nonwoven fabric, the first superabsorbent polymer layer, the second hydrophilic nonwoven fabric, the second superabsorbent polymer, and the pulp sheet are layered in this order from the wearer's skin side. The pants-type absorbent article according to any one of claims 1 to 4, wherein the absorbent sheet is a second absorbent sheet in which the first hydrophilic nonwoven fabric, the first superabsorbent polymer layer, the second hydrophilic nonwoven fabric, the second superabsorbent polymer, the third hydrophilic nonwoven fabric, the third superabsorbent polymer layer, and the pulp sheet are layered in this order from the wearer's skin side. The pants-type absorbent article according to any one of claims 1 to 6, wherein the absorbent sheet has embossed grooves extending from its skin-side surface to the skin-side surface of the pulp sheet, and the embossed grooves include a first embossed groove extending longitudinally through the widthwise center of the skin-side surface of the absorbent sheet, and a second embossed groove including a plurality of embossed grooves intersecting or contacting the first embossed groove at an acute angle. The absorbent article according to claim 7 , wherein the second embossed groove is arranged in an X-shape when viewed in a planar view on the skin-side surface of the absorbent sheet, and an intersection of the second embossed groove arranged in an X-shape when viewed in a planar view is located on the first embossed groove. The pants-type absorbent article according to any one of claims 1 to 8, wherein the absorbent sheet has a thickness of 0.5 mm or more and 5 mm or less. The pants-type absorbent article according to any one of claims 1 to 9, wherein each of the hydrophilic nonwoven fabrics has a basis weight of 10 g/ ^m2 or more and 40 g/ ^m2 or less, and a thickness of 0.05 mm or more and 0.3 mm or less. The pants-type absorbent article according to any one of claims 1 to 10, wherein the pulp sheet has a basis weight of 10 g/ ^m2 or more and 40 g/ ^m2 or less and a thickness of 0.05 mm or more and 0.5 mm or less.