Absorbent article and method for manufacturing absorbent body for absorbent article

Abstract

An elongated absorbent article includes a skin-side top sheet, a non-skin-side back sheet, and an absorbent body disposed between the top sheet and the back sheet, in which the absorbent body has a middle basis weight portion and a low basis weight portion adjacent to the middle basis weight portion, the low basis weight portion having a lower basis weight than the middle basis weight portion, and the low basis weight portion having a lower basis weight than the middle basis weight portion. The low basis weight portion includes a front low basis weight portion and a rear low basis weight portion, the rear low basis weight portion has a narrower width than the front low basis weight portion, and the length of the front low basis weight portion in the longitudinal direction is 40%-120% of the length of the absorber in the transverse direction.

Description

Technical Field

[0001] The present invention relates to an absorbent article and a method for producing an absorbent body for the absorbent article. Background Art

[0002] As absorbent articles such as sanitary napkins for menstruation, there is known a product that is used for long periods of time or at night, and the product is long in total length so as to face the back of the wearer's buttocks. In such absorbent articles, a structure for preventing body fluids from leaking out is discussed, which enables the main body to fit the shape of the body and to be closely attached to the back.

[0003] For example, Patent Document 1 describes an absorbent article in which a middle region extending in the width direction is formed at the rear side of the center of the wings in the front-to-back direction and at the front side of the rear end edge of the absorbent core, and the basis weight of the absorbent material in the middle region is lower than that of the first and second regions in front and behind the middle region. It is also described that this structure can prevent body fluids from leaking out to the rear when the wearer is lying on his back.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-67820 Summary of the invention

[0005] [Problems to be solved by the present invention]

[0006] However, even with the above-mentioned conventional structure, when the wearer makes a large movement while wearing the garment, the garment cannot be kept in close contact with the body, and there is still a concern about leakage of body fluids. Therefore, it is desired to maintain close contact with the body during movement.

[0007] Therefore, an object of one aspect of the present invention is to provide an absorbent article which has excellent fit across the front and back of a wearer's body and can prevent leakage of body fluids.

[0008] [Methods used to solve the problem]

[0009] One aspect of the present invention is an elongated absorbent article comprising a top sheet on the skin side, a back sheet on the non-skin side, and an absorbent body arranged between the top sheet and the back sheet, wherein the absorbent body has a middle basis weight portion and a low basis weight portion adjacent to the middle basis weight portion, the low basis weight portion has a basis weight lower than that of the middle basis weight portion, the low basis weight portion comprises a front low basis weight portion and a rear low basis weight portion, the rear low basis weight portion has a width narrower than that of the front low basis weight portion, and the longitudinal length of the front low basis weight portion is 40% to 120% of the transverse length of the absorbent body.

[0010] [Effects of the Invention]

[0011] According to one aspect of the present invention, it is possible to provide an absorbent article which has excellent fit across the front and back of a wearer's body and can prevent leakage of body fluids. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a plan view of the absorbent article according to one embodiment as viewed from the skin side.

[0013] Figure 2 It is along Figure 1 Cross-sectional view of line II.

[0014] Figure 3 It is along Figure 1 Cross-sectional view along line II-II.

[0015] Figure 4 yes Figure 1 A top view of an absorbent article with the absorbent body exposed.

[0016] Figure 5 yes Figure 4 A partial enlarged view of the absorber shown.

[0017] Figure 6 It is a schematic cross-sectional view showing a state where the absorbent article is worn.

[0018] Figure 7 It is a diagram showing other changes in the planar shape of the low basis weight portion.

[0019] Figure 8 It is a top view of the absorbent article according to the modified example in a state where the absorbent body is exposed.

[0020] Fig. 9 yes Figure 8 A partial enlarged view of .

[0021] Fig.10 This is a schematic diagram showing an apparatus for manufacturing absorbent articles.

[0022] Fig.11 It is a top view of the absorbent body mold used in the manufacturing method of the absorbent article of this embodiment.

[0023] Fig.12 yes Fig.11 A local enlarged view (an enlarged view of part P1 and part P2).

[0024] Fig.13 yes Fig.11 Cross-sectional view of .

[0025] Fig.14 This is a plan view of an absorbent body mold used in a method for manufacturing an absorbent article according to a modified example.

[0026] Fig.15 yes Fig.14 A local enlarged view (enlarged view of part P3).

[0027] Fig.16 yes Fig.14 Cross-sectional view of .

[0028] Fig.17 It is a top view used to illustrate the position of the fold line when individual packaging is performed.

[0029] Fig.18 It is along Fig.17 Schematic diagram of the cross section of line III-III.

[0030] Fig.19 It is Fig.17 Schematic diagram of a cross-section of an individually packaged absorbent article obtained in a state of. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that in each of the drawings, the same or corresponding structures are given the same reference numerals and their description is omitted unless otherwise specified.

[0032] <Basic structure of absorbent articles>

[0033] The absorbent article according to the present embodiment may be a sanitary napkin, a diaper, a pad for light incontinence, etc. The basic structure of the absorbent article according to the present embodiment is described below by taking a sanitary napkin for nighttime use or long-term use as an example. Figure 1 is a top view showing the absorbent article 1. In addition, Figure 2 It means along Figure 1 The cross-sectional diagram of line II, Figure 3 It means along Figure 1 Cross-sectional view along line II-II.

[0034] like Figures 1 to 3 As shown, the absorbent article 1 has: a liquid-permeable top sheet 3, which is arranged on the side facing the skin of the wearer when wearing, that is, the skin side; and a liquid-impermeable back sheet 2, which is arranged on the non-skin side (underwear side) of the side opposite to the above-mentioned skin side. Furthermore, an absorbent (absorbent core) 4 is arranged between the back sheet 2 and the top sheet 3. These back sheets 2, absorbents 4 and top sheets 3 are laminated to form a main body (absorbent article main body) 8. The absorbent 4 is configured so that it will not extend from the back sheet 2 and the top sheet 3 when viewed from above. In addition, the edge of the back sheet 2 and the edge of the top sheet 3 can be joined by an adhesive, heat sealing, etc. at both ends of the length direction D1.

[0035] As shown in the figure, the absorbent article 1 is in the shape of an elongated pad (a shape in which the thickness is smaller than the width and length). In this specification, the longitudinal direction (front-back direction) of the absorbent article 1 is set as D1, and the transverse direction (left-right direction or width direction) orthogonal to the longitudinal direction D1 is set as D2. The longitudinal direction D1 is a direction corresponding to the front-back direction of the body of the wearer when wearing the absorbent article 1; the transverse direction D2 is a direction corresponding to the left-right direction of the body.

[0036] exist Figures 1 to 3 In the embodiment shown, the main body 8 has a plan view shape that is substantially line-symmetrical with respect to the center line (center line in the length direction) CL extending in the length direction D1, but the shape of the main body 8 is not necessarily line-symmetrical. In addition, the structure of the absorbent article 1 and the main body 8 other than the shape (including the thickness and density of the absorbent body 4, the size and position of the compressed groove, the shape and size of the flap extending from the main body 8 in the transverse direction D2, etc.) may be substantially symmetrical with the center line CL as the axis of symmetry, or may be asymmetrical.

[0037] The back sheet 2 can be a sheet material having at least water-blocking property, for example, a sheet material made of olefin resins such as polyethylene and polypropylene. In addition, a laminated nonwoven fabric laminated with nonwoven fabric on a polyethylene sheet, etc., and a laminated sheet of a nonwoven fabric that is substantially liquid-impermeable by a waterproof film therebetween can be used. In addition, it is more desirable to use a sheet material having moisture permeability from the viewpoint of preventing dampness. As such a water-blocking and moisture permeable sheet material, a microporous sheet obtained by extending in one or two axial directions after melting and mixing an inorganic filler in an olefin resin such as polyethylene or polypropylene and molding a sheet can be used. The back sheet 2 can be a sheet material having the same outer shape as the outer shape of the absorbent article 1.

[0038] The top sheet 3 is a liquid-permeable sheet that allows body fluids such as menstrual blood, leucorrhea, and urine to penetrate rapidly. As the top sheet 3, a nonwoven fabric with holes or holes or a porous plastic sheet can be appropriately used. As the raw material fiber constituting the nonwoven fabric, for example, the following materials can be used alone or in combination of two or more: synthetic fibers such as olefins such as polyethylene, polypropylene, polyester, and polyamide, regenerated fibers such as rayon and cuprammonium fibers, and blended fibers thereof, and natural fibers such as cotton. In addition, as the processing method of the nonwoven fabric, spunlace, spunbond, hot bond, meltblown, and needle punch are listed. Among these processing methods, it is preferred from the viewpoint that the spunlace can manufacture nonwoven fabrics rich in softness, the spunbond can manufacture nonwoven fabrics rich in drapability, and it is preferred from the viewpoint that the hot bond can manufacture bulky and soft nonwoven fabrics. In addition, composite fibers such as core-sheath type fibers, side-by-side fibers, and split fibers with a high melting point fiber as the core and a low melting point fiber as the sheath can also be used.

[0039] The absorbent 4 is not limited, as long as it is a material that can absorb and retain body fluids, and preferably includes cotton pulp and absorbent polymers. As absorbent polymers, superabsorbent polymer granular powder (superabsorbent polymer (SAP)), superabsorbent polymer fiber (superabsorbent fiber (SAF)) and combinations thereof can be used. As pulp, pulp composed of cellulose fibers such as chemical pulp and dissolving pulp obtained from wood, rayon, acetate and other artificial cellulose fibers can be listed. As raw materials for chemical pulp, broadleaf wood, coniferous wood, etc. can be used, but coniferous wood is suitable for use in terms of long fiber length and other aspects.

[0040] Synthetic fibers may also be mixed in the absorbent 4. As synthetic fibers, fibers mixed from two or more of the following materials can be used: polyolefins such as polyethylene or polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, and copolymers thereof. In addition, composite fibers such as core-sheath type fibers, parallel type fibers, and split type fibers having a core with a fiber having a high melting point and a sheath with a fiber having a low melting point can also be used. In addition, hydrophilic agents can be used to surface-treat hydrophobic fibers to add fibers with affinity for body fluids. Preferably, the absorbent 4 is manufactured by fiber accumulation or airlaid method.

[0041] In the absorbent body 4, a plurality of absorbent body compression portions that are recessed from the top sheet 3 side to the back sheet 2 side may also be partially formed, and they are separated from each other when viewed from above. In addition, the absorbent body 4 may also be wrapped with a wrapping sheet formed of colored or non-colored (white) crepe paper or non-woven fabric to prevent it from folding and breaking or preventing the spillage of polymer particles. The specific structure of the absorbent body 4 and the preferred manufacturing method will be described in detail later.

[0042] On both sides of the absorbent article 1, that is, on the side in the transverse direction D2, side panels 7, 7 are arranged on the skin side along the length direction D1. The side panels 7 can be made of raw materials that have been subjected to appropriate water-repellent treatment or hydrophilic treatment in whole or in part to prevent the penetration of body fluids or to correspond to the purpose of improving the touch of the skin. The side panels 7 preferably contain natural fibers, synthetic fibers, regenerated fibers, etc., or are non-woven fabrics composed of these fibers. When the side panels 7 are non-woven fabrics, they can be hot air non-woven fabrics, spunlace non-woven fabrics, spunbond non-woven fabrics, melt-blown non-woven fabrics, etc., and are preferably hot air non-woven fabrics from the perspective of being difficult to attach creases, difficult to produce wrinkles, and being soft and capable of improving the touch of the skin. It should be noted that for the side panels 7, water-repellent treatment can also be performed with water-repellent agents such as silicone and paraffin.

[0043] The side piece 7 may also be folded back on the inner side in the transverse direction D2 to form a multi-layered belt-shaped portion extending along the side of the main body 8. It should be noted that elastic stretchable components may be arranged in an extended state along the length direction D1 between the multi-layers to form wrinkles. The description of the folding back and wrinkle structure of the side piece 7 is omitted in this specification, and the illustration is also omitted in the drawings.

[0044] The absorbent article 1 may include: a body fluid discharge outlet facing region C, which faces the body fluid discharge outlet (the example shown is the vaginal opening) of the wearer when worn; a front region F, which is adjacent to the front of the body fluid discharge outlet facing region C and is a region extending to the front end of the absorbent article 1; a perineum facing region (middle region) M, which is adjacent to the rear of the body fluid discharge outlet facing region C and is facing the vicinity of the perineum of the wearer when worn; and a buttocks facing region B, which is adjacent to the rear of the perineum facing region M, is a region extending to the rear end of the absorbent article 1, and faces the buttocks of the wearer when worn. Furthermore, the buttocks facing region B includes: a front buttocks facing region B1, which is adjacent to the perineum facing region M; and a rear buttocks facing region B2, which is adjacent to the rear of the front buttocks facing region B1. The front buttocks facing region B1 is mainly a region facing the gluteal groove (groove of the buttocks), that is, a region facing the part including the anus. The rear buttocks facing area B2 may be a portion behind the gluteal groove or further behind the rear end of the gluteal groove, and in particular, may be a portion facing the boundary between the buttocks and the legs that is further behind the gluteal groove (above when standing). It should be noted that the description of the facing relationship between the area of ​​the main body 8 and the wearer's body can be set as a general range when the wearer wears the absorbent article in the usual wearing manner when lying down, and is only a rough reference.

[0045] The length D1 of the region C facing the body fluid discharge outlet can be 50 to 120 mm, and the length D1 of the region B facing the buttocks can be 90 to 230 mm. In addition, according to the structure of the present embodiment, for example, the total length of the perineum facing region M and the buttocks facing region B is preferably the length of the buttocks facing region B in the length direction D1, which is larger than the length of the wing WF in the length direction D1 and is longer at the rear. In addition, the length D1 of the front buttocks facing region (gluteal groove facing region) B1 in the length direction D1 can be 40 to 100 mm, and the length D1 of the rear buttocks facing region B2 in the length direction D1 can be 40 to 120 mm. In addition, the total length of the absorbent article 1 in the length direction D1 can be 250 to 450 mm.

[0046] The absorbent article 1 may have a pair of wings WF, WF, which extend outward in the transverse direction D2 from the two side portions of the region C facing the body fluid discharge port. On the non-skin side of the wings WF, WF, a deviation prevention material (not shown) may be provided. When worn, the wings WF, WF can be folded back toward the non-skin side and attached to the underwear through the deviation prevention material, so that the wings WF, WF and the main body 8 can be used to clamp the underwear. In this way, the absorbent article 1 is reliably fixed to the underwear. The wings WF, WF are formed by joining the extension portions of the side panels 7, 7 extending outward in the transverse direction D2 to the extension portions of the back panel 2 extending outward in the transverse direction D2.

[0047] In addition, a pair of buttocks retaining sheets HF, HF may be formed, which extend from the perineum facing area M to the buttocks facing area B and extend outward from the side of the main body 8 in the transverse direction D2. The buttocks retaining sheets HF, HF prevent body fluids from leaking out from the rear of the absorbent article 1 and expand the contact area with the buttocks, thereby also having the function of making the entire absorbent article 1 less likely to shift relative to the underwear, especially less likely to shift in the transverse direction D2, and stabilizing the wearing position of the absorbent article 1. The buttocks retaining sheets HF, HF may also be formed by joining the extension portions of the side sheets 7, 7 extending outward in the transverse direction D2 and the extension portions of the back sheet 2 extending outward in the transverse direction D2.

[0048] <Specific structure of absorber>

[0049] Figure 4 It means self Figure 1 FIG. 1 is a top view of the absorbent article 1 with the top sheet 3 and the side sheets 7, 7 removed and the absorbent body 4 exposed. Figure 4As shown, the basis weight of the absorbent body 4, specifically, the pulp basis weight is not uniform as a whole, but varies according to different parts. The absorbent body 4 mainly includes: a middle basis weight portion 4M having a medium basis weight; a high basis weight portion 4H having a higher basis weight than the middle basis weight portion 4M; and a low basis weight portion 4L having a lower basis weight than the middle basis weight portion 4M. The low basis weight portion 4L includes: a front low basis weight portion 4Lf having the same width as the absorbent body 4 arranged in the perineum-facing region M; and a rear low basis weight portion 4Lb elongated in the length direction D1, which is arranged in the gluteal groove-facing region B1. Preferably, the rear low basis weight portion 4Lb is formed in the center of the transverse direction D2 in a manner spanning the center line in the length direction. In addition, the middle basis weight portion 4M may include: a front middle basis weight portion 4Mf, which is mainly formed in the body fluid discharge port facing region C; and a rear middle basis weight portion 4Mb, which is mainly formed in the rear buttocks facing region B2. It should be noted that the absorbent body 4 contains pulp (or a fibrous material mainly composed of pulp) and a water-absorbent polymer as described above, and preferably the basis weight of the water-absorbent polymer is the same as that of the entire absorbent body 4. At this time, the magnitude relationship of the pulp basis weight is reflected in the magnitude relationship of the basis weight.

[0050] The basis weight of the low basis weight portion 4L is preferably 200 to 500 gsm, more preferably 300 to 400 gsm. The basis weight of the medium basis weight portion 4M is preferably 300 to 600 gsm, more preferably 400 to 500 gsm. The basis weight of the high basis weight portion 4H is preferably 500 to 850 gsm, more preferably 600 to 750 gsm. It should be noted that in order to exert the effect produced by the low basis weight portion 4L in this embodiment, the basis weight of the low basis weight portion 4L can be 60 to 90% of the basis weight of the medium basis weight portion 4M. The above basis weight can adopt a pulp basis weight.

[0051] The low basis weight portion 4L, the middle basis weight portion 4M and the high basis weight portion 4H may be basis weight uniform areas with almost uniform basis weight in each part. If the basis weight in a specified part or specified area is almost uniform, it means that even if there are parts with slightly different basis weights, the difference from the average basis weight in the specified part or specified area is less than 20% of the average basis weight, preferably less than 10%, and more preferably less than 5%. The front low basis weight portion 4Lf and the rear low basis weight portion 4Lb may have different basis weights and have almost uniform basis weights respectively. At this time, the basis weight of the rear low basis weight portion 4Lb may be slightly smaller than that of the front low basis weight portion 4Lf.

[0052] Figure 5 Indicated in Figure 4 An enlarged view of the area including the low basis weight portion 4L. Figure 4 and Figure 5As shown, the rear low base weight portion 4Lb is surrounded by the middle base weight portion 4M on both sides and the rear. The rear low base weight portion 4Lb is easier to bend than the surroundings, and when a force is applied from the outside in the lateral direction D2, the rear low base weight portion 4Lb can be easily raised toward the top sheet 3. It should be noted that a narrow mountain portion can also be formed to fit the narrow position of the gluteal groove. In addition, as Figure 4 and Figure 5 As shown, a middle basis weight portion 4M having a higher basis weight is arranged behind the rear low basis weight portion 4Lb. That is, the rearward extension range of the rear low basis weight portion 4Lb is closer to the front than the rear end of the absorbent body 4, preferably to the vicinity of the boundary between the gluteal groove facing region B1 and the rear buttocks facing region B2. Therefore, it is possible to suppress the mountain portion formed by the rear low basis weight portion 4Lb from continuing to, for example, the rear end of the absorbent body 4. Therefore, it is easy to make the rear buttocks facing region B2 fit the shallower part of the wearer's gluteal groove, or the relatively flat part closer to the rear than the end position of the gluteal groove.

[0053] It should be noted that the two sides and the rear of the rear low basis weight portion 4Lb are composed of the middle basis weight portion 4M, so the side portion of the gluteal groove facing area B1 in the transverse direction D2 has a higher rigidity than the center of the transverse direction D2, so it is not easy to produce unwanted wrinkles and folds even when deformed. Therefore, it is easy to make the middle basis weight portion 4M of the gluteal groove facing area B1 fit the surface of the buttocks on the side of the gluteal groove. In addition, when the absorbent article 1 is folded during individual packaging, it is not easy to cause creases even if the fold line is located at the middle basis weight portion 4M, and it can be quickly unfolded along the underwear during wearing.

[0054] In addition, the length D1 of the front low basis weight portion 4Lf is 40 to 120% of the length of the absorbent in the transverse direction, and can be flexibly deformed over a wide range. Therefore, for example, even when the wearer opens and closes the legs or moves forward and backward, the absorbent article body 8 can deform to follow the shape change of the body part under the crotch, and can effectively prevent leakage. In particular, when the mountain portion generated by the bulge of the above-mentioned rear low basis weight portion 4Lb is relatively deep in the gluteal groove, the gluteal groove facing area B1 of the body is not easy to move, so under its influence, the perineum facing area M that is closer to the front than the gluteal groove facing area B1 is also not easy to deform. In contrast, the front low basis weight portion 4Lf extending in the transverse direction D2 can be flexibly deformed as described above, so that the front low basis weight portion 4Lf can be deformed to follow the shape change of the body part in front of the gluteal groove while maintaining the state of being closely attached to the gluteal groove through the rear low basis weight portion 4Lb. As described above, according to this embodiment, a wide range along the front-back direction of the body, particularly high fit from the perineum to the rear of the gluteal groove can be obtained, and this fit can be maintained even during movement.

[0055] Figure 6 Schematically shows a cross-sectional view of the absorbent article 1 when being worn, cut along the transverse direction D2. Figure 6 (a) is a schematic cross-sectional view of the absorbent article 1 cut at the perineum-facing region M. Figure 6 (b) is a schematic cross-sectional view of the absorbent article 1 cut at the gluteal groove facing region B1. Figure 6 (c) is a schematic cross-sectional view of the absorbent article 1 cut at the rear buttocks facing region B2. Figure 6 As shown in (a), the perineum facing area M is located between the legs Lg and faces the perineum. Even if the legs Lg are brought together and moved forward and backward from this state, the perineum facing area M can follow the perineum and the surrounding body parts and adhere to them tightly because the perineum facing area M includes the highly flexible front low basis weight portion 4Lf. Figure 6 As shown in (b), the rear low basis weight portion 4Lb is included in the gluteal groove facing area B1, so the rear low basis weight portion 4Lb can bulge to form a mountain and enter the cleft (gluteal groove) of the buttocks Den and adhere closely. Figure 6 As shown in (c), the middle base weight portion 4M is included in the entire lateral direction D2 in the rear buttocks facing area B2, so it can be closely attached to the relatively flat surface of the body part with a shallow gluteal groove or no gluteal groove. That is, according to this embodiment, it is possible to provide an absorbent article that can be deformed in a manner that fits the shape of various parts of the front and back of the body.

[0056] It should be noted that the length x of the front low basis weight portion 4Lf in the lateral direction D2 is f It is preferably 30 to 110 mm, and more preferably 60 to 100 mm. In addition, from the viewpoint of the flexibility of the lifting body 8 in the lateral direction D2, the length x of the front low basis weight portion 4Lf in the lateral direction D2 is f The length y in the longitudinal direction D1 is 70% or more, preferably 80% or more, and more preferably equal to the length in the transverse direction D2 of the absorber 4. f It is preferably 55 to 80 mm, and more preferably 60 to 70 mm. f The length y is 40 to 120%, more preferably 50 to 110%, and even more preferably 60 to 100%, of the length of the absorbent body 4 in the transverse direction D2. f The low base weight portion can cover the area facing the perineum, while ensuring flexibility to follow movements such as opening and closing of the legs.

[0057] The length x of the rear low basis weight portion 4Lb in the transverse direction D2 bIt is preferably 5 to 30 mm, and more preferably 10 to 20 mm. Furthermore, the length x of the rear low basis weight portion 4Lb in the lateral direction D2 is b It may be 5 to 25% of the length (width) in the transverse direction D2 of the absorbent body 4. b The mountain formed by the bulge of the rear low base weight portion 4Lb can be set to an appropriate size to enter the gluteal groove and fit closely therewith. In addition, the length y of the length direction D1 of the rear low base weight portion 4Lb is b It is preferably 40 to 80 mm, and more preferably 50 to 70 mm. b The mountain portion formed when worn can be formed with an appropriate length corresponding to the gluteal groove, and can be suppressed from continuing to an area corresponding to a portion where the gluteal groove is shallow or has no gluteal groove.

[0058] The length y of the rear low basis weight portion 4Lb in the longitudinal direction D1 is b The length x of its transverse direction D2 b The ratio (y b / x b ) may be 2 to 8. By using this ratio, the mountain portion formed by the bulge of the rear low basis weight portion 4Lb can be set to an appropriate size so as to enter the gluteal groove and closely adhere thereto.

[0059] It should be noted that from the perspective of flexible deformation, although it is also considered to form slits (linear or strip-shaped gaps running through the thickness direction) in the absorbent 4 to replace the low basis weight portion 4L, unlike the slits, the low basis weight portion 4L can ensure the existence of the absorbent to enhance the absorption and retention of body fluids, and is therefore preferred.

[0060] From the viewpoint of obtaining flexibility along the longitudinal center line CL from the perineum-facing region M to the gluteal groove-facing region B1, it is preferable to Figure 4 As shown, the front low basis weight portion 4Lf and the rear low basis weight portion 4Lb are made continuous. On the other hand, as long as the above-mentioned effects of the two parts are not hindered, the front low basis weight portion 4Lf and the rear low basis weight portion 4Lb may be made discontinuous, for example, the middle basis weight portion 4M may be arranged between the front low basis weight portion 4Lf and the rear low basis weight portion 4Lb.

[0061] like Figure 1 As shown, the high basis weight portion 4H is formed at the center in the transverse direction D2 of the body fluid discharge outlet facing region C. This portion is in contact with the body fluid discharge outlet (vaginal opening, etc.). Figure 1 In the example shown, the high basis weight portion 4H is surrounded by the front middle basis weight portion 4Mf, but may be in contact with the front low basis weight portion 4Lf located at the rear. The high basis weight portion 4H may have a greater thickness than the surrounding front middle basis weight portion 4Mf.

[0062] Figure 7 4L shows a modified example of the low basis weight portion 4L. Figure 4 and Figure 5 In the example shown, the front low basis weight portion 4Lf has a rectangular shape with long sides in the lateral direction D2 when viewed from above, and the rear low basis weight portion 4Lb has a rectangular shape with long sides in the longitudinal direction D1 when viewed from above. Figure 7 In the example shown in (a), the width of the front of the rear low basis weight portion 4Lb gradually widens as it goes forward, and at the position connected to the front low basis weight portion 4Lf, it has a transverse direction D2 length equal to the transverse direction D2 length of the front low basis weight portion 4Lf. In this shape, the width of the front of the mountain portion formed by the bulge of the rear low basis weight portion 4Lb becomes wider, so that it becomes easy to fit near the starting position of the gluteal groove.

[0063] exist Figure 7 In the example shown in (b), Figure 7 Similarly to the example shown in (a), the width of the front of the rear low basis weight portion 4Lb gradually widens toward the front, thereby obtaining the same advantages. Figure 7 In the example shown in (b), the contour line is formed as a gentle curve near the boundary between the front low basis weight portion 4Lf and the rear low basis weight portion 4Lb. In addition, the contour line in front of the front low basis weight portion 4Lf is also formed as a gentle curve at the end in the transverse direction D2. If there is a curved portion, the stress that may be generated due to the difference in basis weight can be reduced.

[0064] <Compression groove>

[0065] Refer again Figures 1 to 3 In the main body 8 of the absorbent article 1 of the present embodiment, a compression groove (also called fit embossing) formed by compressing at least the top sheet 3 and the absorbent body 4 from the top sheet 3 side can be formed. The compression groove has the function of introducing and retaining body fluids, so it can be beneficial to prevent the spread of body fluids or induce body fluids. In the illustrated example, the compression groove may include a plurality of compression grooves (illustrated by the reference numerals 10, 11, 12, and 13). The compression groove can be formed to be linearly symmetrical with the longitudinal center line CL of the absorbent article 1 as the symmetry line when viewed from above, but it does not necessarily have to be linearly symmetrical. The compression groove can be formed, for example, by passing a laminate formed by laminating at least the top sheet 3 and the absorbent body 4 between a pair of pressure rollers. At this time, by arranging a roller having a convex portion corresponding to the compression groove on the surface on the top sheet 3 side of the above-mentioned laminate, arranging a roller without concave and convex on the surface on the absorbent body 4 side of the laminate, and clamping it by two rollers, it is possible to apply pressure. It should be noted that the compression groove may include a low compression portion and a high compression portion, wherein the high compression portion is compressed at a higher pressure than that in the low compression portion. In the drawings, the high compression portion is indicated in black.

[0066] like Figure 1 As shown, the pair of central compressed grooves 10, 10 mainly extend along the longitudinal direction D1 from the body fluid outlet facing region C to the perineum facing region M. The pair of central compressed grooves 10, 10 are arranged to be separated from each other on both sides of the longitudinal centerline CL and do not overlap with the high basis weight portion 4H. The separation distance between the pair of central compressed grooves 10, 10 in the transverse direction D2 can also be constant or variable. For example Figure 1 As shown, it can be set to be small near the boundary between the body fluid outlet facing area C and the perineum facing area M, and set to be large again behind it, and it decreases as it goes to the back. The pair of central compression grooves 10, 10 have the function of preventing leakage to the outside in the transverse direction D2 in the body fluid outlet facing area C and guiding the body fluid in the longitudinal direction D1. In addition, it can promote the deformation of the center of the transverse direction D2 of the body fluid outlet facing area C to bulge toward the skin side.

[0067] A first rear compression groove 11 is formed behind a pair of central compression grooves 10, 10, and the first rear compression groove 11 is separated from the pair of central compression grooves 10, 10. The first rear compression groove 11 is formed in the buttocks facing region B, mainly in the buttocks facing region B1. The first rear compression groove 11 is formed across the lengthwise center line CL, and has a shape that bulges backward as a whole. More specifically, the first rear compression groove 11 may have a shape including a horseshoe-shaped compression groove 11h and lateral compression grooves 11s, 11s, wherein the horseshoe-shaped compression groove 11h has a horseshoe shape (or a shape in which the ends are close to each other in a U-shaped shape) that overlaps the lengthwise center line CL, and the lateral compression grooves 11s, 11s branch from the side of the horseshoe-shaped compression groove 11h and extend forward.

[0068] A second rear compression groove 12 may be formed behind the first rear compression groove 11, and the second rear compression groove 12 is separated from the first rear compression groove 11. The second rear compression groove 12 is a groove extending along the transverse direction D2 and has a shape protruding toward the rear. In addition, a front compression groove 13 is formed in front of the pair of central compression grooves 10, 10. Figure 1 In the example shown, the front compressed groove 13 has a closed shape formed by combining compressed grooves that are convex and curved forward with different radii of curvature.

[0069] like Figure 1 and Figure 4 As shown, a pair of central compression grooves 10, 10 ( Figure 4The pair of central compression grooves 10, 10 are mainly arranged in the low basis weight portion 4L, and the rear ends 10bt, 10bt of the pair of central compression grooves 10, 10 are located in the middle basis weight portion 4M, which has a higher basis weight than the low basis weight portion 4L.

[0070] Generally speaking, when the compression groove is formed in a region with a lower basis weight than the absorbent body, the compressive force that can be applied is weaker than in other regions, and the compression groove may not be properly formed due to insufficient compression. In addition, when the compression of the front end of the compression groove is insufficient, the compressed but unjoined portion in the thickness direction may peel off (lift up), and the compression groove may not be able to perform its function. Figure 1 and Figure 4 As shown, if the rear ends 10bt, 10bt of a pair of central compression grooves 10, 10 extend rearwardly beyond the rear end of the front low base weight portion 4Lf and into the rear middle base weight portion 4Mb, the compression grooves can be reliably formed, so that warping can be prevented from occurring at the ends of the central compression grooves 10, 10.

[0071] The rear ends 10bt, 10bt of the pair of central compression grooves 10, 10 are formed in a manner from the perineum facing region M to the gluteal groove facing region B1, and face the part of the body shape that changes from the perineum to the gluteal groove when worn. Therefore, force is easily applied to the rear ends 10bt, 10bt of the pair of central compression grooves 10, 10, and it is easy to cause warping. From this point of view, it is preferred that the rear ends 10bt, 10bt of the pair of central compression grooves 10, 10 are located in the rear middle base weight portion 4Mb.

[0072] It should be noted that the rear ends 10bt, 10bt of the pair of central compression grooves 10, 10 may partially overlap with the rear low basis weight portion 4Lb, but from the viewpoint of preventing the compression groove from warping, it is preferred that the rear low basis weight portion 4Lb ( Figure 5 ), or only a small portion overlaps.

[0073] <Deformation of the absorber>

[0074] Figure 8 2 shows an absorbent body 4' according to a modified example. Figure 8 is corresponding to Figure 4 , which is a diagram of a state in which the top sheet 3 and the side sheets 7, 7 are removed from the self-absorbent article 1. Figure 8 In the example shown, Figure 4Similarly to the example shown, the absorbent body 4' has a low basis weight portion 4L, a middle basis weight portion 4M and a high basis weight portion 4H, but in this example, a basis weight changing portion 4V is formed between the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb. The basis weight changing portion 4V is located between the rear end of the front low basis weight portion 4Lf and the front end of the rear middle basis weight portion 4Mb, whereby the rear low basis weight portion 4Lb is sandwiched between the basis weight changing portion 4V and the rear middle basis weight portion 4Mb from the transverse direction D2. The basis weight changing portion 4V has a basis weight that is higher than the low basis weight portion 4L and lower than the middle basis weight portion 4M. Furthermore, the basis weight of the basis weight changing portion 4V increases gradually or in stages from the front toward the rear, that is, as it approaches the rear middle basis weight portion 4Mb.

[0075] By forming the basis weight change portion 4V, a sharp change in the basis weight in the length direction D1 can be avoided. In the case where the difference between the basis weight of the front low basis weight portion 4Lf and the basis weight of the rear middle basis weight portion 4Mb is large, or unnecessary stress is generated at the boundary between the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb, and the desired deformation of the main body 8 cannot be obtained, or the difference in the thickness of the absorbent body 4' is too large to cause discomfort, but this embodiment can prevent such undesirable conditions. In the top view shape of the low basis weight portion 4L of this embodiment, the sum of the lengths of the boundary lines between the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb is relatively long, and is 75 to 95% of the length of the absorbent body 4' in the transverse direction D2 according to the situation, so the above-mentioned undesirable conditions are easily highlighted. Therefore, especially in the case where the difference between the basis weight of the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb is large, it is preferred to set the basis weight change portion 4V between the two.

[0076] Fig. 9 Indicated in Figure 8 4 is an enlarged view of the area containing the low basis weight portion 4L. Fig. 9 In the example shown, the basis weight changing portion 4V is composed of a portion whose basis weight is different in two stages, namely, a first portion 4V1 and a second portion 4V2. However, the basis weight changing portion 4V may be composed of a portion whose basis weight is different in three or four stages, or may be a portion whose basis weight is gradually changed as described above.

[0077] Of the first portion 4V1 and the second portion 4V2, the first portion 4V1 disposed in the front and adjacent to the front low basis weight portion 4Lf has a basis weight lower than the second portion 4V2 disposed in the rear and adjacent to the rear medium basis weight portion 4Mb. v It can be 2 to 15 mm, and can be the length y of the length direction D1 of the rear low basis weight portion 4Lb. b 5-20% of the total.

[0078] In addition, if Fig. 9As shown, it is preferred that the pair of central compression grooves 10, 10 also extend on the basis weight change portion 4V. Furthermore, it is preferred that the pair of central compression grooves 10, 10 extend beyond the rear end of the basis weight change portion 4V to the rear middle basis weight portion 4Mb. That is, it is preferred that the central compression grooves 10, 10 extend in the length direction D1 in a manner spanning the basis weight change portion 4V, and the rear ends 10bt, 10bt of the central compression grooves 10, 10 are arranged in the rear middle basis weight portion 4Mb. Thus, the portion near the rear end of the central compression grooves 10, 10 is arranged in the region where the basis weight gradually or stage-by-stage changes from the low basis weight portion 4L to the middle basis weight portion 4M. Since the compression portion can be formed more reliably by compressing the area with a high basis weight as described above, the portion near the rear end of the central compression grooves 10, 10 is compressed gradually or stagewise, that is, gradually more reliably and deeply, as it moves toward the end (rear end) 10bt, 10bt, thereby preventing peeling (warping) near the rear end and preventing discomfort when touching the compression groove.

[0079] <Method for producing absorbent body>

[0080] Next, a method for producing the absorbent body 4 will be described. Fig.10 Schematically shows a manufacturing device 60 for manufacturing an absorbent body 4. In this device, the absorbent material to be the absorbent body is supplied to an absorbent body mold having a plurality of suction openings on the bottom surface for fiber accumulation and demolding to obtain the absorbent body 4. Fig.10 As shown in FIG. 6 , a pulp supply section 61 is provided upstream of the manufacturing device 60, and mainly supplies a fiber material including pulp. The pulp supply section 61 may be provided with a defibrator, and the pulp sheet or the like is defibrated by the defibrator and supplied to the duct 62. A polymer particle introduction section 63 may be provided in the middle of the duct 62 to supply super absorbent polymer particles. Therefore, in the duct 62, the pulp and the super absorbent polymer particles are mixed, and the mixed absorbent material is supplied to the fiber accumulation drum 65.

[0081] On the outer peripheral surface of the fiber accumulation drum 65, a plurality of absorbent molds 50 are arranged to be separated in the circumferential direction. The fiber accumulation drum 65 rotates, so that the absorbent molds 50, 50, ... can sequentially receive and contain the absorbent material. The bottom surface of the absorbent mold 50 is formed of a porous plate or a mesh plate, and is configured to attract gas through the openings to gather the absorbent material on the bottom surface of the absorbent mold 50. In addition, the gas is discharged through the openings, so that the absorbent 4 can be supplied to a conveying member 66 such as a conveyor belt. A negative pressure chamber and a positive pressure chamber are provided inside the fiber accumulation drum 65, and it is configured so that the gas can be attracted and discharged separately by each chamber.

[0082] A brush roller (or brush) 64 may be provided at a downstream position in the duct 62. The brush roller 64 can scrape off excess absorbent material after fiber accumulation, and can make the surface of the absorbent material accumulated in the absorbent mold 50 uniform.

[0083] The absorbent body 4 supplied to the conveying member 66 can be compressed in the thickness direction by the compressing member 67. The compressing member 67 may be Fig.10 The pair of rollers shown may be a pair of pressing members approaching from both sides of the absorbent body 4. The compression members 67 improve the shape retention of the absorbent body 4.

[0084] Fig.11 1 is a top view showing an example of an absorbent body mold 50 provided on a fiber accumulation drum 65. Fig.12 (a) means Fig.11 An enlarged view of part P1, Fig.12 (b) means Fig.11 This is an enlarged view of part P2. Fig.13 (a) means Fig.11 The Y1-Y1 section, Fig.13 (b) means Fig.11 Y2-Y2 section. Figures 11 to 13 The absorbent body mold 50 shown is used to manufacture the absorbent body 4 ( Figures 1 to 5 The longitudinal direction of the absorbent mold 50 corresponds to the longitudinal direction D1 of the absorbent 4 to be obtained, and the transverse direction of the absorbent mold 50 corresponds to the transverse direction D2 of the absorbent 4. Therefore, in the drawings, the longitudinal direction and transverse direction of the absorbent mold 50 are respectively indicated by the reference numerals D1 and D2.

[0085] like Fig.11 and Fig.13 As shown, the absorbent mold 50 is formed as a concave shape that can collect the absorbent material. In this example, the bottom surface of the absorbent mold 50 is formed as a porous plate, that is, a plurality of openings 55, 55, ... are formed on the bottom surface of the absorbent mold 50. Fig.12 ). The opening pattern is not uniform throughout the absorbent mold 50, and the opening area ratio, that is, the ratio of the total area of ​​the openings per unit area of ​​the bottom surface, varies depending on the location. More specifically, the bottom surface of the absorbent mold 50 has a low concentration area Z L (low opening area ratio), and the front middle cluster area Z Mf and the rear middle cluster area Z Mb (Sometimes collectively referred to as "Z M ”) (opening area ratio is lower than that of the low concentration zone Z L The opening area ratio is high). The front middle gathering area Z Mf and the rear middle cluster area ZMb The opening area ratio and structure may be the same or different. If they are the same, it is preferred because the complexity of making the absorbent mold 50 can be reduced. It should be noted that the bottom surface of the absorbent mold 50 may also be formed by a mesh plate composed of a combination of wires.

[0086] Low agglomeration area Z L 、Z in the front middle cluster area Mf and the rear middle cluster area Z Mb Corresponding to the obtained absorbent 4 ( Figure 4 The front low base weight portion 4Lf, the front middle base weight portion 4Mf and the rear middle base weight portion 4Mb are located in the front middle concentration area Z. Mf A recessed portion 51 ( Fig.13 ), this concave portion 51 corresponds to the high basis weight portion 4H of the absorbent body 4 ( Figure 4 In the front middle gathering area Z Mf When a concave portion 51 is formed in the middle, the opening area ratio of the bottom surface of the concave portion 51 may be the same as or different from the opening area ratio of the surrounding area. Mf By making the opening area ratio of the bottom surface of the recessed portion 51 in the middle larger, the amount of absorbent material accumulated in the recessed portion 51 can be further increased. This structure is suitable for the case where the basis weight difference between the high basis weight portion 4H and the front middle basis weight portion 4Mf is to be increased in order to further increase the basis weight of the high basis weight portion 4H. Mb A non-porous convex component 52 is provided inside, and this non-porous convex component 52 corresponds to the rear low basis weight portion 4Lb of the absorbent body 4. This non-porous convex component 52 can also be formed by arranging a component formed separately from the absorbent body mold 50 in the rear middle accumulation zone Z Mb It can also be arranged in the rear middle gathering area Z when the absorbent mold 50 is formed. Mb The bottom surface of the absorbent body mold 50 is formed in such a way that non-hole convex portions are formed therein.

[0087] like Fig.12 (a) and Fig.12 As shown in (b), the shape of an opening 55 on the bottom surface of the absorbent mold 50 is a square when viewed from above. However, the shape of the opening 55 is not limited to the shape shown in the figure, and can also be a quadrilateral other than a square, a polygon other than a quadrilateral, a circle, an ellipse, etc. In addition, in this example, the front middle accumulation area Z Mf (Z M ) has a shape and area that is similar to that of the low concentration zone Z L The shape and area of ​​one opening 55 in the Fig.12 (a) and (b)). Therefore, in the low agglomeration area Z Land the front middle cluster area Z Mf (Z M ) between the opening area ratios becomes the difference in density or density of the openings 55. It should be noted that in the middle clustering zone Z M The shape and area of ​​the opening 55 formed on the bottom surface of the low concentration zone Z can also be different from L The shape and area of ​​the opening 55 formed on the bottom surface of the M The open area ratio is lower than that of the low concentration area Z L However, when the shape and area of ​​one opening are the same as a whole, the complexity of making the absorbent mold 50 can be reduced, so it is preferred.

[0088] It should be noted that the middle agglomeration area Z M (Z in the middle agglomeration area ahead Mf and the rear middle cluster area Z Mb ) can have an opening area ratio of 25 to 50%. L The opening area ratio can be 5 to 20%.

[0089] In the absorbent body mold 50 used in this embodiment, Figure 4 The area corresponding to the front low basis weight portion 4Lf (i.e., the low concentration area Z L ) is larger than the opening area ratio of the bottom surface of the middle base weight portion 4M (i.e., the middle clustering area Z M ) has a small opening area ratio on the bottom surface. In other words, the low basis weight of the front low basis weight portion 4Lf is obtained by reducing the opening area ratio on the bottom surface. Here, generally speaking, in order to form regions with different basis weights according to the locations within the absorbent body 4, there is also a means of reducing the thickness of the accumulated absorbent material by making the bottom surface level (bottom surface height) different by locally forming depressions and projections on the bottom surface of the absorbent mold. This means that the basis weight can be reliably made different, but if the bottom surface level is made different, steps will be generated between regions, so if a wide range of low basis weight portions is to be formed, the absorbent material is easily broken at the edge of the steps. Therefore, in the manufacturing process of the absorbent body 4, for example, in the process of scraping the material by the brush roller 64, the absorbent body may be easily discontinuous at the steps, and the absorbent body 4 may be broken into many small segments, or the desired thickness of the absorbent body 4 cannot be obtained. In particular, the front low basis weight portion 4Lf ( Figure 4 and Figure 5 The length of the lateral direction D2 is relatively long, and there is a relatively long boundary line (a boundary line along the lateral direction D2) between the middle base weight portion 4M, so it is easy to be broken into many small sections due to steps. Fig.11 and Fig.13As shown, the opening area ratio of the bottom surface is made different from that of the surrounding area, thereby obtaining a low basis weight for the front low basis weight portion 4Lf, and in the low accumulation area Z L With the middle agglomeration area Z M There is no step at the boundary between them (the bottom surface is at the same level). Therefore, it is possible to prevent the undesirable situation that the front low basis weight part 4Lf and the middle basis weight part 4M are broken into many small sections.

[0090] On the other hand, as described above, in the area corresponding to the square low base weight portion 4Lb, a non-hole convex member 52 ( Fig.11 and Fig.13 ). By having the non-porous convex component 52, the thickness of the accumulated absorbent material is thinned by an amount corresponding to the thickness of the non-porous convex component 52, so the basis weight can be reliably reduced. In this way, unlike the above-mentioned front low basis weight portion 4Lf, the low basis weight of the rear low basis weight portion 4Lb can be obtained by changing the bottom surface level (the height of the bottom surface). In the case of the rear low basis weight portion 4Lb that is short in length (narrow in width) and small in area in the transverse direction D2, it is preferred to use the non-porous convex component 52 as described above, rather than by reducing the area ratio of the openings. The reasons are listed below. When two areas with different opening area ratios are adjacent to each other, when fiber accumulation is performed, fibrous materials such as pulp are accumulated in a cross-border manner, so the boundary between the above-mentioned two areas will not be very clear. Therefore, if the non-porous convex member 52 is used to form a low basis weight by reducing the opening area ratio of the bottom surface in the area corresponding to the rear low basis weight portion 4Lb, the boundary between the rear low basis weight portion 4Lb and the rear middle basis weight portion 4Mb surrounding the rear low basis weight portion 4Lb will be unclear, and there is a possibility that the area of ​​the rear low basis weight portion 4Lb with a narrow width cannot be ensured. In contrast, according to this embodiment using the non-porous convex member 52, the thickness of the accumulated absorbent material can be reduced and the amount of accumulation can be reliably reduced, so the low basis weight area can be more reliably ensured.

[0091] Thus, in this embodiment, the front low basis weight portion and the rear low basis weight portion are formed by different means corresponding to the shape of each low basis weight portion (particularly the length in the transverse direction D2). Therefore, the area of ​​the low basis weight portion can be reliably ensured without causing the absorbent body to be broken into many small sections.

[0092] <Modification of absorbent body mold>

[0093] Figures 14 to 16 An absorbent body mold 50 ′ according to a modified example is shown. Fig.14 is a top view of the absorbent mold 50', and corresponds to Fig.11 In addition, Fig.15 express Fig.14 An enlarged view of part P3. Fig.16(a) means Fig.14 The Y1'-Y1' section, Fig.16 (b) means Fig.14 Y2'-Y2' section. Figures 14 to 16 The absorbent body mold 50' shown is a modified example for manufacturing the absorbent body 4' ( Figure 8 and Fig. 9 )The mold used.

[0094] The basic structure of the absorbent mold 50' is Figures 11 to 13 The absorbent mold 50' is the same as the absorbent mold 50 shown in the figure. The absorbent mold 50' is overall formed into a concave shape capable of collecting the absorbent material, and the bottom surface of the absorbent mold 50' is also formed by a porous plate. Figures 11 to 13 ) Similarly, the bottom surface of the absorbent mold 50' has a low concentration area Z L (the area ratio of the opening is low), and the front middle gathering area Z Mf and the rear middle cluster area Z Mb (Z M ) (Opening area ratio in the low concentration zone Z L However, in the absorbent mold 50', in the low concentration area Z L and the rear middle cluster area Z Mb There is a change cluster zone Z between V . Change Cluster Z V This is the area corresponding to the basis weight change portion 4V. V With a lower concentration area Z L High opening area ratio, and has a higher concentration area Z than the rear Mb The opening area ratio is low, and it increases towards the rear, that is, from the low concentration zone Z L Starting from the rear, towards the central gathering area Z Mb The area ratio of the opening increases gradually or in stages.

[0095] Fig.15 yes Fig.14 Part P3, that is, across the low concentration area Z L , Change Cluster Zone Z V and the rear middle cluster area Z Mb In the absorbent mold 50', the shapes and areas of the openings 55, 55, ... in each region are equal, and the opening area ratios are different by different densities or concentrations of the openings 55, 55, ... Fig.15 As shown, the change cluster area Z V Contains low concentration area Z L Adjacent first zone Z V1 , and the rear middle cluster area ZMb Adjacent second zone Z V2 In the first zone Z V1 The opening area ratio of the second zone Z V2 The opening area ratio is small. V1 The first part 4V1 (corresponding to the absorbent body 4') Fig. 9 etc.), Zone 2 Z V2 Corresponding to the second 4V2 ( Fig. 9 In the example shown in the figure, the change cluster area Z V The opening area ratio is formed in the first zone Z along the length direction of the absorbent mold 50'. V1 and the second zone Z V2 The two-stage change, but the change agglomeration area Z V The opening area ratio may also change in three or more stages, or may change gradually along the length direction D1.

[0096] Thus, in order to form the front low basis weight portion 4Lf, by L and the rear middle cluster area Z Mb The opening area ratio in the length direction changes in the concentration zone Z V , so that the concentration of absorbent material from the low concentration area Z L Towards the rear central gathering area Z Mb The basis weight of the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb is gradually changed, so that a sharp change in the basis weight in the middle of the absorbent body can be prevented, thereby improving the continuity of the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb. Therefore, when the basis weight difference between the front low basis weight portion 4Lf and the rear middle basis weight portion 4Mb is large, it is possible to prevent the occurrence of a discontinuous portion of the absorbent body.

[0097] Furthermore, one aspect of the present invention may be a method of manufacturing an absorbent article using the absorbent body manufactured by the above-mentioned manufacturing method.

[0098] <Relationship between absorbent article and folding of individual package>

[0099] The folding position when the absorbent article according to the present embodiment is individually packaged with a packaging sheet is also described below. When a single package of the absorbent article (individually packaged absorbent article) is obtained, the absorbent article is placed on the inner surface of the packaging sheet, and the absorbent article and the packaging sheet are folded at least three times inwardly (top sheet side) in the length direction. Fig.17 Indicates that Figure 1 The absorbent article 1 shown is placed in the packaging sheet 20. Fig.18 Schematically indicates along Fig.17 The cross section of line III-III. In addition, Fig.19 The absorbent article 100 and the packaging sheet 20 are Fig.18 FIG. 1 is a diagram of a state in which the absorbent article is folded into a single package.

[0100] like Fig.17 As shown, the absorbent article 1 and the packaging sheet 20 are folded at three fold lines (FL1, FL2 and FL3) extending along the transverse direction D2. That is, it is folded into four. When folding, after the end of the absorbent article 1 is folded back at the third fold line FL3 near the boundary between the front buttocks facing area (gluteal groove facing area) B1 and the rear buttocks facing area B2, the rear part is folded back at the second fold line FL2 passing through the perineum facing area M. Furthermore, the front part is folded back at the first fold line FL1 near the boundary between the front area F and the body fluid discharge outlet facing area C. It should be noted that the adhesive tape 22 is arranged after the absorbent article 1 is folded and packaged together with the packaging sheet 20. Fig.17 and Fig.18 The figure also shows the position of the adhesive tape 22. It should be noted that the wing pieces WF, WF and the buttocks holding pieces HF, HF are preferably folded back along the folding lines (not shown) in the longitudinal direction D1 before folding along the three folding lines (FL1, FL2 and FL3).

[0101] exist Fig.18 and Fig.19 The schematic diagram also shows the positions of the front middle basis weight portion 4Mf, the high basis weight portion 4H, the front low basis weight portion 4Lf, the rear low basis weight portion 4Lb and the rear middle basis weight portion 4Mb. The basis weight may not necessarily be reflected in the thickness according to the process after the absorbent is manufactured, but Fig.18 and Fig.19 In the schematic diagram of FIG. , the basis weight is reflected in the thickness. Fig.18 As shown, in this embodiment, the folding line is set at a position avoiding the high basis weight portion 4H, so that the folding process becomes easy. Furthermore, the second folding line FL2 passes through the front low basis weight portion 4Lf, and the third folding line FL3 passes through the rear end of the rear low basis weight portion 4Lb, preferably passing through the rear low basis weight portion 4Lb, thereby further improving the folding ease.

[0102] In addition, if Fig.19As shown, in the state of the absorbent article 100 in a single package, the adhesive tape 22 overlaps the front low basis weight portion 4Lf, rather than the area containing the rear low basis weight portion 4Lb and the rear middle basis weight portion 4Mb. The rear low basis weight portion 4Lb may become concave in the center of the transverse direction D2, so there will be a situation where it is not easy to attach the adhesive tape 22 that is also configured in the center of the transverse direction D2. In contrast, according to this embodiment, the adhesive tape 22 is overlapped on the front low basis weight portion 4Lf having a uniform basis weight throughout the transverse direction D2 in a manner that does not overlap the rear low basis weight portion 4Lb, thereby enabling the adhesive tape 22 to be attached more reliably.

[0103] The present invention is described above based on the embodiments, but the present invention is not limited to these embodiments. It should be noted that the above embodiments can be variously changed, modified, replaced, added, deleted and combined within the scope of the patent application, which also belongs to the technical scope of the present invention.

[0104] Furthermore, specific aspects of the present invention are described below.

[0105] (Note 1)

[0106] The form of Note 1 is an elongated absorbent article, comprising a top sheet on the skin side, a back sheet on the non-skin side, and an absorbent body arranged between the top sheet and the back sheet, wherein the absorbent body has a middle basis weight portion and a low basis weight portion adjacent to the middle basis weight portion, the low basis weight portion has a basis weight lower than that of the middle basis weight portion, the low basis weight portion comprises a front low basis weight portion and a rear low basis weight portion, the rear low basis weight portion has a width narrower than that of the front low basis weight portion, and the length direction of the front low basis weight portion is 40% to 120% of the transverse length of the absorbent body.

[0107] According to the form of the above-mentioned supplementary note 1, when worn, the rear low basis weight portion with a short length in the transverse direction at the rear can be easily raised toward the top sheet side. Through this raising, a mountain portion with a size that fits the narrow position of the gluteal groove can be formed. Thus, the fit to the gluteal groove is improved, and leakage at the gluteal groove can be prevented, for example, body fluids can be transferred from the body fluid discharge outlet to the gluteal groove and backwards to leak out (also called downstream leakage).

[0108] In addition, in this form, a front low basis weight portion having a predetermined length in the longitudinal direction is formed. Therefore, the front part in the low basis weight portion can be flexibly deformed in a wide range. Therefore, for example, even when the wearer performs the opening and closing action of the legs or the action of moving forward and backward, the absorbent article body can be deformed as the shape of the part of the crotch in front of the gluteal groove changes. In particular, when the bulge of the above-mentioned rear low basis weight portion is relatively deep into the gluteal groove, the gluteal groove facing area of ​​the main body will be difficult to move and difficult to deform, so under this influence, there will be a situation where the area in front of the gluteal groove facing area is also difficult to deform. However, according to this form, a front low basis weight portion that can be flexibly deformed over a wide range is formed in front of the rear low basis weight portion, so that the absorbent article body is deeply and fits the gluteal groove, and excellent fit is obtained for the body part in front of the gluteal groove. In this way, according to this form, in a wide range along the front and back direction of the body, especially from the perineum to the back of the gluteal groove, high fit can be obtained, and the fit can also be maintained when performing actions.

[0109] (Note 2)

[0110] In the embodiment of Supplementary Note 2, the transverse length of the front low basis weight portion is equal to the transverse length of the absorbent body.

[0111] According to the embodiment of Supplementary Note 2, the front low basis weight portion can be further flexibly deformed in the lateral direction, so the fit during the movement of the wearer can also be improved.

[0112] (Note 3)

[0113] In the embodiment of Supplementary Note 3, the transverse length of the rear low basis weight portion is 5% to 25% of the transverse length of the absorbent body.

[0114] According to the embodiment of Supplementary Note 3, the width of the mountain portion formed by the rear low-base-weight portion can be set to an appropriate size to correspond to the deep part of the gluteal groove.

[0115] (Note 4)

[0116] In the form of Note 4, the middle base weight portion includes a front middle base weight portion and a rear middle base weight portion, the front middle base middle portion is adjacent to the front of the front low base weight portion, the rear middle base weight portion is adjacent to the rear of the front low base weight portion and is adjacent to both sides and the rear of the rear low base weight portion, at least in the top sheet and the absorbent body, there are compression grooves recessed from the top sheet side to the back sheet side, the compression grooves include a pair of central compression grooves, the pair of central compression grooves extend along the length direction of the area facing the body fluid discharge outlet of the wearer when worn, and the pair of central compression grooves extend rearward over the rear end of the front low base weight portion.

[0117] According to the embodiment of Supplementary Note 4, by forming a pair of central compression grooves, rapid diffusion of body fluid in the lateral direction can be suppressed, and body fluid can be guided along the longitudinal direction to prevent leakage. In addition, appropriate deformation of the area facing the body fluid discharge port can be promoted.

[0118] In addition, generally speaking, when the compression groove is formed in a region with a lower basis weight than the absorbent body, the compression force that can be applied is weaker than that in other regions, and the compression groove may not be reliably formed. In addition, when the compression of the front end of the compression groove is insufficient, there may be a case where the compression groove cannot function because of peeling (warping) in the compressed and non-joined portion in the thickness direction. In contrast, in this form, a pair of central compression grooves extend rearward over the rear end of the front low basis weight portion, that is, the rear end of the pair of central compression grooves extends to the rear middle basis weight portion adjacent to the rear of the front low basis weight portion, so that warping at the end of the central compression groove can be prevented, and the compression groove can function appropriately.

[0119] (Note 5)

[0120] In the form of Note 5, a basis weight changing portion is formed between the front low basis weight portion and the rear middle basis weight portion, and the basis weight of the basis weight changing portion is higher than the basis weight of the front low basis weight portion and lower than the basis weight of the rear middle basis weight portion, and gradually or stagewise increases toward the rear.

[0121] According to the embodiment of the above-mentioned supplementary note 5, the basis weight changing portion can avoid a sharp change in the basis weight in the length direction, so that no unnecessary stress is generated in the area between the front low basis weight portion and the rear middle basis weight portion, and the body shape can be deformed. Therefore, the flexible deformation of the area from the perineum facing area to the gluteal groove facing area can be promoted.

[0122] (Note 6)

[0123] In the form of Note 6, the absorbent body also has a high basis weight portion in the area facing the body fluid discharge outlet of the wearer when worn, and the high basis weight portion is surrounded by the front middle basis weight portion and has a higher basis weight than the front middle basis weight portion.

[0124] According to the embodiment of the above-mentioned supplementary note 6, by having a high basis weight portion in the area facing the body fluid discharge outlet, the absorbent article body can be closely attached to the body fluid discharge outlet to prevent leakage. In this embodiment, at least three areas with different basis weights (low basis weight portion, medium basis weight portion and high basis weight portion) are included.

[0125] (Note 7)

[0126] The form of Note 7 is a method for manufacturing an absorbent body, which is used in absorbent articles, wherein the absorbent body has a medium basis weight portion and a low basis weight portion adjacent to the medium basis weight portion, the low basis weight portion has a basis weight lower than that of the medium basis weight portion, the low basis weight portion includes a front low basis weight portion and a rear low basis weight portion, the rear low basis weight portion has a width narrower than that of the front low basis weight portion, and the length of the front low basis weight portion in the longitudinal direction is 40% to 120% of the transverse length of the absorbent body, the method for manufacturing the absorbent body includes the steps of fiberizing and demolding the absorbent material that will become the absorbent body in an absorbent body mold, the absorbent body mold is provided with a plurality of openings for suction on the bottom surface, the area ratio of the openings in the area corresponding to the front low basis weight portion is smaller than the area ratio of the openings in the area corresponding to the medium basis weight portion, and a non-hole convex part is provided in the area corresponding to the rear low basis weight portion.

[0127] According to the form of the above-mentioned note 7, an absorbent article having the same effect as the form of note 1 can be manufactured. In addition, in the absorbent mold used in the manufacturing method according to this form, the area ratio of the openings on the bottom surface of the absorbent mold in the area corresponding to the front low basis weight portion is smaller than the area ratio of the openings on the bottom surface in the area corresponding to the middle basis weight portion. That is, the difference in basis weight between the front low basis weight portion and the middle basis weight portion is obtained by making the area ratio of the openings on the bottom surface of the absorbent mold different. Generally speaking, in order to make the basis weight different in the absorbent, there is also a means of forming a convex portion and a concave portion locally on the bottom surface of the absorbent mold to make the bottom surface level different. By this means, the basis weight difference can be made relatively easily and reliably. However, making the bottom surface level different will produce steps between regions, so when a wide range of low basis weight portions is to be formed, it is easy to cause the absorbent material (especially fibrous materials such as pulp) to be broken at the edge of the step. Therefore, in the steps of fiber accumulation, material scraping, demoulding, etc. of the absorbent material, it may be broken into many small sections due to the steps, and the desired thickness of the absorbent may not be obtained. The front low basis weight portion in this form is a low basis weight portion with a relatively long length in the transverse direction (spreading over a wide range in the transverse direction), so the low basis weight is obtained by making the area ratio of the openings on the bottom surface different instead of making the bottom surface level different, thereby preventing the undesirable situation of being broken into many small sections between the middle basis weight portion.

[0128] On the other hand, in this form, a non-porous convex component is provided in the area corresponding to the rear low basis weight portion, and the low basis weight of the rear low basis weight portion is obtained by the non-porous convex component. The layer of absorbent material gathered on the non-porous convex component will be thinner than the surrounding area by an amount corresponding to the thickness of the non-porous convex component after the scraping step after fiber accumulation, so the low basis weight can be reliably obtained. Here, if the non-porous convex component is not used but the low basis weight is obtained by reducing the opening area ratio of the bottom surface of the absorbent mold in the same way as the front low basis weight portion, the absorbent materials gathered in the areas on both sides of the narrow non-porous convex component (corresponding to the areas of the middle basis weight on both sides in the transverse direction) overlap each other, resulting in unclear boundaries, so there is a possibility that the area of ​​the rear low basis weight portion cannot be ensured. However, this possibility can be avoided according to this form. In this way, in this form, the front low basis weight portion and the rear low basis weight portion are formed by different means corresponding to the shape of each low basis weight portion. Therefore, the region of the low basis weight portion can be reliably ensured without causing a problem such as the absorbent body being broken into a number of small pieces.

[0129] (Note 8)

[0130] In the form of Note 8, the middle base weight portion includes a front middle base weight portion and a rear middle base weight portion, the front middle base middle portion is adjacent to the front of the front low base weight portion, the rear middle base weight portion is adjacent to the rear of the front low base weight portion and to both sides and the rear of the rear low base weight portion, a base weight change portion is formed between the front low base weight portion and the rear middle base weight portion, the area ratio of the openings in the area corresponding to the base weight change portion is larger than the area ratio of the openings in the area corresponding to the front low base weight portion, and smaller than the area ratio of the openings in the area corresponding to the rear middle base weight portion, and gradually or stagewise increases toward the rear.

[0131] According to the form of the above-mentioned supplementary note 8, an absorbent article can be manufactured that has the same effect as the form of supplementary note 5. In addition, by changing the basis weight between the rear low basis weight portion and the rear middle basis weight portion, a sharp change in basis weight between the two can be avoided, thereby reducing the possibility of damage to the continuity in the longitudinal direction of the absorbent body.

[0132] (Note 9)

[0133] In the form of Note 9, the absorbent body also has a high basis weight portion in the area facing the body fluid outlet of the wearer when worn, and the high basis weight portion is surrounded by the front middle basis weight portion and has a higher basis weight than the front middle basis weight portion, and the area corresponding to the high basis weight portion is a recessed portion formed in the area corresponding to the front middle basis weight portion.

[0134] According to the form of the above-mentioned supplementary note 9, an absorbent article having the same effect as the form of supplementary note 6 can be manufactured. In addition, in the area of ​​the front middle basis weight portion, a high basis weight area, that is, a high basis weight portion is further formed. At this time, the opening area ratio on the bottom surface of the area corresponding to the high basis weight portion can be the same as the opening area ratio of the area corresponding to the front middle basis weight portion, or it can be made larger than the opening area ratio of the area corresponding to the front middle basis weight portion.

[0135] This application claims priority based on Japanese patent application No. 2022-088308 filed on May 31, 2022, the entire contents of which are incorporated herein by reference.

[0136] Description of Reference Numerals

[0137] 1. Absorbent articles (sanitary napkins)

[0138] 2 back piece

[0139] 3 Top sheet

[0140] 4.4' absorber

[0141] High basis weight of 4H absorbent

[0142] 4L low basis weight absorbent

[0143] 4Lb rear low basis weight section (slim low basis weight section)

[0144] 4Lf front low basis weight section

[0145] 4M absorbent mid-weight

[0146] 4Mb rear center base

[0147] 4Mf front center weight

[0148] 4V Basis Weight Change Unit

[0149] 4V1 Part 1

[0150] 4V2 Part 2

[0151] 7 side panels

[0152] 8 Main body (absorbent article main body)

[0153] 10 Central compression slot

[0154] 10bt rear end of central compression tank

[0155] 11First rear compression groove

[0156] 11h horseshoe shaped compression groove

[0157] 11s side compression slots

[0158] 12 Second rear compression slot

[0159] 13Front compression slot

[0160] 20 pack tablets

[0161] 22 Adhesive tape

[0162] 50, 50' absorber mold

[0163] 51 recess

[0164] 52 Non-hole convex parts

[0165] 55 opening

[0166] 60Absorbent manufacturing device

[0167] 61 Pulp Supply Department

[0168] 62 Pipe

[0169] 63 polymer particle introduction part

[0170] 64 brush roller

[0171] 65 fiber accumulation roller

[0172] 66Conveying parts

[0173] 67 compression parts

[0174] B Buttocks facing area

[0175] B1 Front buttocks facing area (gluteal groove facing area)

[0176] B2 rear buttocks facing area

[0177] C Area facing the body fluid discharge outlet

[0178] CL length direction center line

[0179] D1 length direction

[0180] D2 Horizontal direction

[0181] F front area

[0182] FL1, FL2, FL3 lines

[0183] HF hip retainer

[0184] M middle area (area facing the perineum)

[0185] WF Wing

[0186] Z Mf Front center gathering area

[0187] ZMb Rear middle gathering area

[0188] Z L Low agglomeration area

[0189] Z V Change agglomeration area.

Claims

1. An absorbent article, which is an elongated absorbent article and comprises a top sheet on the skin side, a back sheet on the non-skin side, and an absorbent body arranged between the top sheet and the back sheet, wherein: The absorbent body has a middle basis weight portion and a low basis weight portion adjacent to the middle basis weight portion, the low basis weight portion having a lower basis weight than the middle basis weight portion, The low basis weight portion includes a front low basis weight portion and a rear low basis weight portion, the rear low basis weight portion having a narrower width than the front low basis weight portion, The length of the front low basis weight portion in the longitudinal direction is 40% to 120% of the length of the absorbent body in the transverse direction.

2. The absorbent article according to claim 1, wherein The transverse length of the front low basis weight portion is equal to the transverse length of the absorbent body.

3. The absorbent article according to claim 1 or 2, wherein: The transverse length of the rear low basis weight portion is 5% to 25% of the transverse length of the absorbent body.

4. The absorbent article according to claim 1 or 2, wherein: The middle base weight portion includes a front middle base weight portion and a rear middle base weight portion, wherein the front middle base weight portion is adjacent to the front of the front low base weight portion, and the rear middle base weight portion is adjacent to the rear of the front low base weight portion and adjacent to both sides and the rear of the rear low base weight portion. At least in the top sheet and the absorbent body, a compression groove is formed which is recessed from the top sheet side to the back sheet side, and the compression groove includes a pair of central compression grooves, and the pair of central compression grooves extend along the length direction of the body fluid discharge outlet facing area facing the body fluid discharge outlet of the wearer when worn, The pair of central compression grooves extend rearwardly beyond the rear end of the front low basis weight portion.

5. The absorbent article according to claim 4, wherein: A basis weight changing portion is formed between the front low basis weight portion and the rear middle basis weight portion, The basis weight of the basis weight changing portion is higher than the basis weight of the front low basis weight portion and lower than the basis weight of the rear middle basis weight portion, and gradually or stepwise increases toward the rear.

6. The absorbent article according to claim 4, wherein: The absorbent body further includes a high basis weight portion in the body fluid outlet-facing region facing the body fluid outlet of the wearer when worn, and the high basis weight portion is surrounded by the front middle basis weight portion and has a higher basis weight than the front middle basis weight portion.

7. A method for producing an absorbent body for use in an absorbent article, wherein: The absorbent body has a middle basis weight portion and a low basis weight portion adjacent to the middle basis weight portion, the low basis weight portion having a lower basis weight than the middle basis weight portion, The low basis weight portion includes a front low basis weight portion and a rear low basis weight portion, the rear low basis weight portion having a narrower width than the front low basis weight portion, The longitudinal length of the front low basis weight portion is 40% to 120% of the transverse length of the absorbent body. The manufacturing method of the absorbent body comprises the steps of fiberizing and demoulding the absorbent body material to be the absorbent body in an absorbent body mold, The absorbent mold has a plurality of suction openings on the bottom surface, wherein the area ratio of the openings in the region corresponding to the front low basis weight portion is smaller than the area ratio of the openings in the region corresponding to the middle basis weight portion. A non-hole convex component is provided in a region corresponding to the rear low basis weight portion.

8. The method for producing an absorbent body according to claim 7, wherein: The middle base weight portion includes a front middle base weight portion and a rear middle base weight portion, wherein the front middle base weight portion is adjacent to the front of the front low base weight portion, and the rear middle base weight portion is adjacent to the rear of the front low base weight portion and adjacent to both sides and the rear of the rear low base weight portion. A basis weight changing portion is formed between the front low basis weight portion and the rear middle basis weight portion, The area ratio of the openings in the area corresponding to the basis weight change portion is larger than the area ratio of the openings in the area corresponding to the front low basis weight portion, and smaller than the area ratio of the openings in the area corresponding to the rear medium basis weight portion, and increases gradually or in stages toward the rear.

9. The method for producing an absorbent body according to claim 8, wherein: The absorbent body further comprises a high basis weight portion in the region facing the body fluid discharge outlet of the wearer when worn, the high basis weight portion being surrounded by the front middle basis weight portion and having a basis weight higher than that of the front middle basis weight portion. The region corresponding to the high basis weight portion is a recessed portion formed in a region corresponding to the front middle basis weight portion.

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