WO2024111550A1 - Panty-type sanitary pad and package of panty-type sanitary pad - Google Patents

Abstract

A panty-type sanitary pad (1) comprises: an absorbent body (10) including an absorbent core (11); a belly-side trunk portion (20); and a back-side trunk portion (30) which is a separate member from the belly-side trunk portion (20). When a menstrual blood dropping test of dropping artificial menstrual blood onto a central part in the longitudinal direction and the lateral direction of the absorbent core (11) in a developed and extended state is conducted, the thickness of the central part of the panty-type sanitary pad (1) after the test is smaller than the thickness of the central part of the panty-type sanitary pad (1) before the test.

Description

Shorts-type napkin and packaging for shorts-type napkin

The present invention relates to a shorts-type napkin and a package for the shorts-type napkin.

Patent Document 1 discloses a pants-type wearable article for adults, which includes a front waist panel that forms a front waist region, a rear waist panel that forms a rear waist region, and an absorbent panel with an absorbent body. This pants-type wearable article is intended as a diaper for light incontinence for adults, and so the absorbent body has a water retention capacity of 150 to 400 g. In order to ensure this water retention capacity while allowing the user to wear the diaper without feeling any resistance (so that the user is not aware that they are wearing a diaper), slim absorbent cores are given as examples, including one that contains wood fluff pulp and superabsorbent polymer particles (SAP) and one that is made only of SAP.

JP 2017-47148 A

On the other hand, it is desired that shorts-type napkins fit closely to the wearer's excretory opening and buttocks crease and prevent menstrual blood from leaking along the skin. Furthermore, shorts-type napkins are primarily intended for absorbing menstrual blood, which has a higher viscosity and tends to spread easily on the top sheet, and is excreted in smaller amounts, compared to the urine absorbed by diapers such as those in Patent Document 1. For this reason, if the diaper in Patent Document 1 is used as a shorts-type napkin as is, the SAP that has absorbed the excreted liquid (menstrual blood, sweat, etc.) will cause the absorbent core to swell, which can easily form unevenness on the skin side, reducing the adhesion to the wearer and making it more likely to leak along the skin.

The present invention was made in consideration of the above-mentioned problems with the conventional technology, and its purpose is to provide a shorts-type napkin that is likely to remain in close contact with the wearer's excretory opening, buttocks, etc., even after absorbing excretory fluids such as menstrual blood and sweat.

The main invention for achieving the above-mentioned object is a shorts-type napkin having an absorbent main body with an absorbent core containing water-retentive fibers, a ventral waist portion, and a dorsal waist portion constructed as a separate member from the ventral waist portion, which, in an unfolded and stretched state, has a longitudinal direction, a lateral direction, and a thickness direction that are perpendicular to each other, and which is characterized in that when a menstrual blood drop test is conducted in which artificial menstrual blood is dropped into the central portion of the absorbent core in the longitudinal direction and the lateral direction, the thickness of the central portion of the shorts-type napkin after the menstrual blood drop test is conducted is smaller than the thickness of the central portion of the shorts-type napkin before the menstrual blood drop test is conducted.
Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings.

The present invention provides a shorts-type napkin that is likely to remain in close contact with the wearer's excretory opening, buttocks, etc., even after absorbing excretory fluids such as menstrual blood and sweat.

FIG. 1 is a front view of a shorts-type napkin 1. FIG. 2 is a plan view of the shorts-type napkin 1 in an unfolded and extended state, as viewed from the skin side. 3A is a schematic cross-sectional view taken along a first center line CL1 in FIG. 2, and FIG. 3B is a schematic cross-sectional view taken along a second center line CL2 in FIG. FIG. 13 is a partial plan view of a modified shorts-type napkin 1 in an unfolded and extended state. FIG. 1 is a diagram illustrating a menstrual blood drop test and a saline solution drop test. 3 is an explanatory diagram of a constricted portion 11D of the absorbent core 11. FIG. FIG. 2 is a side view of the shorts-type napkin 1 in a folded state. FIG. 2 is a front view of a package 50 of the shorts-type napkin 1. 9A and 9B are front views of packages 60, 70 of the shorts-type napkin 1 in modified examples.

At least the following points will become apparent from the description of this specification and the accompanying drawings.
(Aspect 1)
A shorts-type napkin having an absorbent main body with an absorbent core containing water-retentive fibers, a ventral waist portion, and a dorsal waist portion constructed as a separate member from the ventral waist portion, wherein, in an unfolded and stretched state, the shorts-type napkin has a longitudinal direction, a lateral direction, and a thickness direction which are perpendicular to each other, and when a menstrual blood drop test is conducted in which artificial menstrual blood is dropped into the central portion of the absorbent core in the longitudinal direction and the lateral direction, the thickness of the central portion of the shorts-type napkin after the menstrual blood drop test is conducted is smaller than the thickness of the central portion of the shorts-type napkin before the menstrual blood drop test is conducted.

The shorts-type napkin described in aspect 1 has better breathability than, for example, a napkin equipped with an integrated outer member that is continuous from the ventral waistband to the rear waistband. In addition, since the ventral waistband and the rear waistband are separate, when the napkin is pulled up to put it on, the pulling force is likely to concentrate on the joints between the waistband and the absorbent body, and the absorbent body is likely to adhere to the wearer's crotch area. In addition, since the absorbent body is less affected by the movement of the body around the waist during wear compared to an integrated outer member, the fit is likely to be maintained. In addition, since the central part of the napkin that contacts the wearer's excretory opening does not expand in thickness after absorbing menstrual blood, it is possible to prevent unevenness from being formed on the skin side, and the napkin is likely to be maintained in close contact with the wearer's excretory opening. As a result, it is possible to prevent menstrual blood from flowing through the gap that occurs between the wearer and the napkin.

(Aspect 2)
A shorts-type napkin having an absorbent main body with an absorbent core containing water-retentive fibers, a ventral waist portion, and a back waist portion constructed as a separate member from the ventral waist portion, wherein when unfolded and stretched, the shorts-type napkin has a longitudinal direction, a lateral direction, and a thickness direction which are perpendicular to each other, and when the absorbent core is divided into three parts in the longitudinal direction, a saline solution is dropped onto a back center portion, which is the center portion in the longitudinal direction and the lateral direction, of the back region, and the thickness of the back center portion of the shorts-type napkin after the saline solution drop test is performed is smaller than the thickness of the back center portion of the shorts-type napkin before the saline solution drop test is performed.

The shorts-type napkin described in aspect 2 has better breathability than, for example, a napkin equipped with an integrated outer member that is continuous from the ventral waistband to the rear waistband. In addition, since the ventral waistband and rear waistband are separate, when the napkin is pulled up to put it on, the pulling force is likely to concentrate on the joints between the waistband and the absorbent body, and the absorbent body is likely to fit closely to the wearer's buttocks. In addition, since the absorbent body is less affected by the movement of the body around the waist compared to an integrated outer member, the fit is likely to be maintained even while wearing it. In addition, the wearer's rear side is more likely to sweat than the ventral side, and sweating is particularly likely to occur when lying on one's back, but since the thickness of the rear center does not expand after absorbing sweat (saline solution), the napkin is likely to be kept in close contact (entered) with the wearer's buttocks. As a result, menstrual blood can be prevented from leaking along the buttocks.

(Aspect 3)
A shorts-type napkin having an absorbent main body with an absorbent core containing water-retentive fibers, a ventral waist portion, and a rear waist portion constructed as a separate member from the ventral waist portion, wherein in an unfolded and extended state, the shorts-type napkin has a longitudinal direction, a lateral direction, and a thickness direction which are perpendicular to one another, and wherein when a menstrual blood drop test is performed in which artificial menstrual blood is dropped onto the central portion of the absorbent core in the longitudinal direction and the lateral directions, the thickness of the central portion of the shorts-type napkin after the menstrual blood drop test is smaller than the thickness of the central portion of the shorts-type napkin before the menstrual blood drop test is performed, and when a saline drop test is performed in which physiological saline is dropped onto the rear central portion, which is the central portion in the longitudinal direction and the lateral directions of the rear region of the absorbent core when divided into three in the longitudinal direction, the thickness of the rear central portion of the shorts-type napkin after the saline drop test is smaller than the thickness of the rear central portion of the shorts-type napkin before the saline drop test.

According to the shorts-type napkin of the third aspect, the napkin has better breathability than, for example, a napkin having an integrated outer member that is continuous from the ventral waistline to the rear waistline. Also, since the ventral waistline and rear waistline are separate, when the napkin is pulled up to put on, the pulling force tends to concentrate on the joints between the waistline and the absorbent body, and the absorbent body tends to fit closely to the wearer's crotch and buttocks. Also, compared to an integrated outer member, the absorbent body is less susceptible to the movement of the body around the waist during wear, so that the fit is easily maintained.
In addition, the central portion of the napkin that comes into contact with the wearer's excretory opening does not expand in thickness after absorbing menstrual blood, which prevents the formation of unevenness on the skin side and helps the napkin to stay in close contact with the wearer's excretory opening, thereby preventing menstrual blood from leaking through the gap between the wearer and the napkin.
In addition, the wearer's back is more susceptible to sweating than the abdomen, especially when lying on one's back, but since the central back portion does not expand in thickness after absorbing sweat (saline solution), the napkin tends to remain in close contact with (enter) the wearer's buttocks, thereby preventing menstrual blood from leaking along the buttocks.

(Aspect 4)
A shorts-type napkin according to any one of aspects 1 to 3, characterized in that in the region between the ventral waist portion and the rear waist portion in the unfolded and stretched state, no elastic member is present outside the absorbent body in the left-right direction.

The shorts-type napkin described in aspect 4 has no elastic members on the left and right outside of the absorbent body in the areas where the wearer's legs come into contact, and the materials do not adhere closely to the body, reducing discomfort around the legs and improving breathability.

(Aspect 5)
A shorts-type napkin according to any one of aspects 1 to 4, wherein the absorbent core has a constricted portion on the inside in the left-right direction in the crotch portion of the shorts-type napkin, which is located under the crotch of a wearer when worn, and wherein, in an unfolded and extended state, when the absorbent core is divided into three in the longitudinal direction, the back region has a greater total weight of the water-retentive fiber than the central region.

The shorts-type napkin described in aspect 5 can reduce the discomfort felt when the absorbent core is pinched between the wearer's legs. In addition, the high total weight of the water-retentive fibers in the back region can effectively absorb sweat generated in the back portion and menstrual blood that flows to the rear. In addition, the wide absorbent core in the back portion can provide a sense of security to the wearer who is worried about rear leakage.

(Aspect 6)
A shorts-type napkin as described in any one of aspects 1 to 5, wherein the absorbent core has a constricted portion on the inside in the left-right direction in the crotch portion of the shorts-type napkin, which is located under the crotch of a wearer when worn, the constricted portion and areas adjacent to the constricted portion on both outsides in the left-right direction contain superabsorbent polymer, and the total weight of the superabsorbent polymer in the adjacent areas is less than that of the constricted portion.

The shorts-type napkin described in aspect 6 can reduce the discomfort (foreign body sensation) felt when the absorbent core is pinched between the wearer's legs. In the constricted portion where the excretory opening abuts, the high total weight of the superabsorbent polymer can firmly absorb and retain menstrual blood. In addition, the low total weight of the superabsorbent polymer located in the area adjacent to the constricted portion can absorb sweat around the legs while preventing discomfort around the legs caused by swelling of the superabsorbent polymer.

(Aspect 7)
A shorts-type napkin according to any one of Aspects 1 to 6, wherein the absorbent core does not contain a superabsorbent polymer.

In the shorts-type napkin described in aspect 7, the highly absorbent polymer does not swell after absorbing excretory fluid (menstrual blood or sweat), and even after the napkin has absorbed the excretory fluid, unevenness is unlikely to form on the skin side, making it easier for the napkin to remain in close contact with the wearer.

(Aspect 8)
A shorts-type napkin according to any one of aspects 1 to 7, characterized in that the absorbent body has a liquid-permeable top sheet, and when the areas of the ventral waistline portion and the dorsal waistline portion located outside the absorbent body in the left-right direction are folded in the left-right direction with the ventral side facing inward, the top sheet is visible through the leg openings.

In the shorts-type napkin described in aspect 8, the pair of leg openings are not covered by the rear waistband, so an air passage is formed that connects the outside and inside of the napkin, making it difficult for moisture to build up inside the napkin. This ensures a comfortable feeling when wearing the napkin.

(Aspect 9)
A shorts-type napkin as described in any one of aspects 1 to 6 and aspect 8, wherein the absorbent core contains a superabsorbent polymer, and has a constricted portion constricted on the inside in the left-right direction in the crotch portion of the shorts-type napkin which is located under the crotch of a wearer when worn, the constricted portion has a narrowest portion which has the shortest length in the left-right direction, and the basis weight of the superabsorbent polymer is lower in the portion of the absorbent core which is located outside the narrowest portion in the left-right direction than in the portion which overlaps with the narrowest portion in the left-right direction.

The shorts-type napkin described in aspect 9 can reduce the discomfort (foreign body sensation) felt when the absorbent core is held between the wearer's legs. In addition, in the area that overlaps with the narrowest part in the left-right direction and abuts the excretory opening, the high basis weight superabsorbent polymer can firmly absorb and retain excreted liquid. Meanwhile, in the four corners outside the narrowest part of the absorbent core, the formation of irregularities due to swelling of the superabsorbent polymer can be suppressed, the absorbent core inside can be stably supported, and the absorbent core can be easily maintained in a tight fit.

(Aspect 10)
A shorts-type napkin according to any one of aspects 1 to 6 and aspects 8 to 9, wherein the absorbent body has a liquid-permeable top sheet, the ventral waist portion and the back waist portion each have a skin-side sheet, a non-skin-side sheet, and a waist elastic member arranged between them that stretches in the left-right direction, the absorbent core contains a superabsorbent polymer, the top sheet has a larger basis weight and thickness than the skin-side sheet, and the total weight of the superabsorbent polymer contained in the absorbent core is lighter than the total weight of the top sheet.

The shorts-type napkin described in aspect 10 improves the feel and cushioning of the top sheet compared to when the top sheet has a smaller basis weight and thickness than the skin-side sheet. This improves the comfort of the top sheet for wearers who experience sensitivity around the vaginal opening during menstruation. Meanwhile, by reducing the total weight of the highly absorbent polymer, the total weight of the absorbent body can be reduced without unnecessarily increasing the water retention capacity of the absorbent body. This prevents the absorbent body from sagging due to its own weight, making it easier for the napkin to remain in close contact with the wearer.

(Aspect 11)
A shorts-type napkin as described in any one of aspects 1 to 6 and aspects 8 to 10, characterized in that the absorbent core has a surface covered with a liquid-permeable core wrap sheet and contains a highly absorbent polymer, and the combined weight of the core wrap sheet and the absorbent core is less than half the weight of the shorts-type napkin.

The shorts-type napkin described in aspect 11 reduces the weight of the core wrap sheet and absorbent core, which affect the water retention capacity of the absorbent body, and the total weight of the absorbent body can be reduced without unnecessarily increasing the water retention capacity of the absorbent body. This prevents the absorbent body from sagging due to its own weight, making it easier for the napkin to remain in close contact with the wearer.

(Aspect 12)
A shorts-type napkin package comprising the shorts-type napkin described in any one of aspects 1 to 11 and a packaging material, the shorts-type napkin package having a vertical direction and a horizontal direction perpendicular to each other, the packaging material being folded to contain the shorts-type napkin, the opposing packaging materials being intermittently joined at least one of a pair of side ends in the horizontal direction, and the left-right direction of the shorts-type napkin contained in the packaging material being aligned along the horizontal direction.

In the shorts-type napkin packaging described in aspect 12, a pair of leg openings located on both sides of the napkin in the left-right direction and the intermittent joints of the packaging are aligned horizontally (left-right), forming an air passage. This makes it difficult for moisture to build up inside the napkin or packaging, ensuring a comfortable feeling when wearing the napkin.

(Aspect 13)
A shorts-type napkin package comprising the shorts-type napkin described in any one of aspects 1 to 11 and a packaging material, the shorts-type napkin package having a vertical direction and a horizontal direction perpendicular to each other, the packaging material being folded to contain the shorts-type napkin, the opposing packaging materials being intermittently joined at least one of a pair of side ends in the horizontal direction, and the left-right direction of the shorts-type napkin contained in the packaging material being aligned along the vertical direction.

In the shorts-type napkin packaging described in aspect 13, a pair of leg openings located on both sides of the napkin in the left-right direction and the intermittent joints of the packaging are not aligned in the same direction. Therefore, outside air that enters the packaging through the intermittent joints is less likely to pass through the leg openings of the napkin and to come into contact with the inside of the napkin (the skin side). Therefore, the napkin can be stored hygienically until the packaging is opened.

====Embodiment===
<<Basic configuration of shorts-type napkin 1>>
Fig. 1 is a front view of a shorts-type napkin 1. Fig. 2 is a plan view of the shorts-type napkin 1 in an unfolded and extended state, as viewed from the skin side. Fig. 3A is a schematic cross-sectional view taken along the first center line CL1 in Fig. 2, and Fig. 3B is a schematic cross-sectional view taken along the second center line CL2 in Fig. 2. Fig. 4 is a diagram showing a part of the plan view of a modified shorts-type napkin 1 in an unfolded and extended state. In the following description, the shorts-type napkin will also be simply referred to as a "napkin." The first center line CL1 is a line extending in the left-right direction at a center point that divides the product in half in the longitudinal direction, and the second center line CL2 is a line extending in the longitudinal direction at a center point that divides the product in half in the left-right direction.

The developed state of the shorts-type napkin 1 refers to a state in which the napkin 1 is opened and developed in a plane by separating a pair of side joining portions 2 provided on both sides of the napkin 1.
The stretched state of the shorts-type napkin 1 refers to a state in which the napkin 1 has been stretched to such an extent that wrinkles in the napkin 1 are no longer visible. Specifically, it refers to a state in which the napkin 1 has been stretched until the dimensions of each component constituting the napkin 1 match or are close to the dimensions of the component alone.

The shorts-type napkin 1 has a vertical direction, a horizontal direction, and a front-to-back direction that are perpendicular to one another, and has a waist opening BH and a pair of leg openings LH. The upper side in the vertical direction corresponds to the waist opening BH side, and the lower side corresponds to the crotch side. The front side in the front-to-back direction corresponds to the wearer's abdomen side, and the rear side corresponds to the wearer's back side. Also, as shown in Figures 3A and 3B, the direction in which the materials that make up the napkin 1 are layered is referred to as the thickness direction. In the thickness direction, the side that comes into contact with the wearer's skin is referred to as the skin side, and the opposite side is referred to as the non-skin side.

The shorts-type napkin 1 also has an absorbent body 10, a ventral waist portion 20 that covers the ventral side of the wearer, and a posterior waist portion 30 that covers the posterior side of the wearer. As shown in FIG. 2, in the unfolded state, the shorts-type napkin 1 has a longitudinal direction, a left-right direction, and a thickness direction that are perpendicular to one another. The longitudinal direction in the unfolded state corresponds to the up-down direction in the shorts-type state.

In the unfolded napkin 1, the ventral waist section 20 and the rear waist section 30 are positioned in a line with a gap between them in the longitudinal direction, and the absorbent body 10 is suspended between them in the longitudinal direction. Each longitudinal end of the absorbent body 10 is joined and fixed to the skin side of the nearest ventral waist section 20 or rear waist section 30. From this state, the absorbent body 10 is folded in half in the longitudinal direction, and the opposing ventral waist section 20 and rear waist section 30 are joined at both left and right sides by a pair of side joints 2 to form a shorts-type napkin 1. Examples of joining methods using the side joints 2 include heat welding, ultrasonic welding, and joining methods using adhesives.

The absorbent body 10 has an absorbent core 11 that absorbs and retains excreted liquids such as menstrual blood, a liquid-permeable surface sheet 12 (e.g., nonwoven fabric, perforated film, etc.) arranged closer to the skin than the absorbent core 11, a liquid-impermeable back sheet 13 (e.g., resin film, etc.) arranged closer to the skin than the absorbent core 11, and a side sheet 14 (e.g., hydrophobic nonwoven fabric, etc.). In addition, the outer periphery of the absorbent core 11 may be covered with a liquid-permeable core wrap sheet 15 such as tissue paper or nonwoven fabric.

A pair of leak-proof walls 3 are provided along the longitudinal direction of the absorbent body 10 on both left and right sides of the absorbent body 10. The leak-proof walls 3 are formed by side sheets 14. Specifically, the side sheets 14 are folded at multiple locations on the left and right sides of the skin side of the top sheet 12 while covering the non-skin side of the back sheet 13, and the leak-proof walls 3 are formed on both left and right sides of the skin side of the top sheet 12. A leak-proof wall elastic member 16 (e.g., rubber thread) is attached to the leak-proof wall 3 in a stretched state along the longitudinal direction. The leak-proof wall 3 stands up on the wearer's skin side based on the stretchability of the leak-proof wall elastic member 16.

The ventral waist section 20 and the dorsal waist section 30 each have a skin- side sheet 21, 31, a non-skin- side sheet 22, 32 laminated on the non-skin side of the skin- side sheet 21, 31, and multiple waist elastic members 23, 33 (e.g. rubber thread) that stretch in the left-right direction. The multiple waist elastic members 23, 33 are arranged in a line in the up-down direction between the skin- side sheet 21, 31 and the non-skin- side sheet 22, 32, and are attached in a stretched state in the left-right direction. The stretchability of the waist elastic members 23, 33 allows the ventral waist section 20 and the dorsal waist section 30 to fit the waist of the wearer.

In addition, cover sheets 24, 34 may be provided to cover the upper end of the absorbent body 10 from the skin side. Examples of the cover sheets 24, 34 include soft nonwoven fabrics. The cover sheets 24, 34 can prevent the upper edge of the absorbent body 10 from digging into the wearer's skin and prevent the absorbent body 10 from opening up.

Also, as shown in FIG. 2, the ventral waistline portion 20 and the back waistline portion 30 have different planar shapes in the unfolded and stretched state. The ventral waistline portion 20 has a vertical length that is roughly the same as the side joint portion 2, and is rectangular in shape that is long in the left-right direction. The back waistline portion 30 has a rectangular waist side portion 30A that overlaps with the ventral waistline portion 20, and a substantially trapezoidal crotch side portion 30B that extends below it (below the side joint portion 2). The crotch side portion 30B is wider from the bottom to the top, and the crotch side portion 30B can cover the wearer's buttocks. This reduces the wearer's anxiety that liquid may leak sideways around the buttocks.

Also, an inclined elastic member 35 (e.g., rubber thread) is provided at the lower end of the back waist portion 30 (the area extending from the lower end of the side joint 2 to the crotch side portion 30B). The inclined elastic member 35 is arranged so as to roughly follow the lower outer edge of the back waist portion 30, and has a portion that inclines downward from both sides of the back waist portion 30 in the left-right direction toward the center, and a portion that extends in the left-right direction at the center of the back waist portion 30. The inclined elastic member 35 is also attached in a stretched state between the skin side sheet 31 and the non-skin side sheet 32, and the stretchability of the inclined elastic member 35 makes it easier for the crotch side portion 30B of the back waist portion 30 to fit the wearer's buttocks and makes it less likely to roll up from the buttocks. Note that, in FIG. 2, three rubber threads are shown as an example of the inclined elastic member 35, but the number of rubber threads is not particularly limited. The inclined elastic member 35 may also be a sheet-like elastic member (such as a stretchable nonwoven fabric or a stretchable film).

The basic structure of the napkin 1 has been described above, but the above-described structure of the napkin 1 is merely an example and is not intended to be limiting.
For example, a liquid-permeable intermediate sheet may be provided between the top sheet 12 and the core wrap sheet 15 .
In addition, the back waist portion 30 may not have the crotch side portion 30B or the inclined elastic member 35 and may have the same planar shape as the ventral waist portion 20, or the ventral waist portion 20 may have a portion extending toward the crotch side.

4, a stretchable sheet may be disposed between the skin side sheets 21, 31 and the non-skin side sheets 22, 32, and the laminated sheets may be intermittently joined, instead of some of the thread-like waistline elastic members 23, 33. In this case as well, the ventral waistline portion 20 and the dorsal waistline portion 30 exhibit stretchability and fit the waistline of the wearer.
4, the length of the portion of the back waist portion 30 extending outward in the left-right direction beyond the inclined elastic member 35 may be shorter than that of the napkin 1 shown in FIGS.

<<About the Fit of the Shorts-type Sanitary Napkin 1>>
In the shorts-type napkin 1 of this embodiment, the ventral waist portion 20 and the rear waist portion 30 are configured as separate members. Therefore, in the shorts-type napkin 1 in an unfolded and stretched state (FIG. 2), the ventral waist portion 20 and the rear waist portion 30 are spaced apart in the longitudinal direction.

Therefore, unlike the present embodiment, the absorbent body 10 has better breathability and is more comfortable to wear than when a single exterior member (e.g., an exterior member having a roughly hourglass-shaped planar shape) that is continuous from the ventral waist portion to the posterior waist portion is provided on the non-skin side of the absorbent body 10. In addition, since the ventral waist portion 20 and the posterior waist portion 30 are separate, when pulling up the napkin 1 to put it on, the pulling force tends to concentrate on the joints between the waist portions (20, 30) and the absorbent body 10, making it easier for the absorbent body 10 to fit closely to the wearer's crotch and buttocks. In addition, compared to an integrated exterior member, the absorbent body 10 is less susceptible to the movement of the body around the waist during wear, so it is easier to maintain a tight fit.

Furthermore, the shorts-type napkin 1 is primarily intended to absorb menstrual blood, which is more viscous than the urine absorbed by diapers, and less is excreted into the napkin 1 (menstrual blood is excreted than urine). Therefore, in the napkin 1, the absorbent core 11 is less likely to sag due to its own weight even after absorbing the excreted liquid, and the absorbent main body 10 remains in close contact with the wearer even without being supported by an exterior member that runs from the ventral waistband to the posterior waistband. As a result, menstrual blood, which is more viscous than urine and tends to spread over the top sheet, can be prevented from leaking through gaps that form between the napkin and the wearer.

Furthermore, it is preferable that there is no exterior member connecting the ventral waist portion 20 and the posterior waist portion 30, which are separate members, at the crotch portion, and that the non-skin side of the absorbent body 10 is exposed at the crotch portion. This further improves the breathability of the absorbent body 10. Also, because there is no material on the outside of the absorbent body 10 in the left-right direction at the crotch portion of the napkin 1, discomfort around the legs is reduced, the wearer is comfortable to wear, and the wearer can move their legs more easily.

In addition, as shown in FIG. 2, in the region (crotch portion 1B) between the ventral waist portion 20 and the posterior waist portion 30 in the unfolded and stretched state, it is preferable that no elastic member is present outside the absorbent body 10 in the left-right direction.

In this case, since there is no elastic member around the wearer's legs (crotch portion 1B), even if materials are present laterally outside the absorbent body 10, the materials do not adhere closely to the wearer's body. This reduces discomfort around the legs, improves comfort, makes it easier for the wearer to move their legs, and improves breathability around the legs. In addition, since the amount of menstrual blood excreted into the napkin 1 is less than the amount of urine excreted into the diaper, there is little risk of leakage from the legs even without the above-mentioned elastic member, which leads to a reduction in materials (lower costs).

In addition, if materials or elastic members are present laterally outboard of the absorbent body 10 in the crotch portion 1B of the napkin 1, the fit of the absorbent body 10 on the laterally outboard side will be improved, but the central portion of the absorbent body 10 in the laterally inboard direction will be less likely to be pressed against the skin by the elastic members or the like. Therefore, by not providing elastic members laterally outboard of the absorbent body 10, leakage due to sagging of the napkin 1 near the vaginal opening can be suppressed. Although not present in this embodiment, an elastic member extending longitudinally may be provided in the central portion of the absorbent body 10 in the laterally inboard direction, away from the skin, than the absorbent core 11. This will improve adhesion to the vaginal opening.

FIG. 5 is a diagram for explaining the menstrual blood drop test and the saline drop test.
Furthermore, in the case of the shorts-type napkin 1 of this embodiment, when a menstrual blood drop test is conducted in which artificial menstrual blood is dropped onto the longitudinal and lateral central portion R1 of the absorbent core 11 in the unfolded and extended state (Figure 5), the thickness of the central portion R1 of the shorts-type napkin 1 after the menstrual blood drop test is smaller than the thickness of the central portion R1 of the shorts-type napkin 1 before the menstrual blood drop test is conducted.

In the menstrual blood dripping test, a scene in which the napkin 1 is actually used is simulated, and artificial menstrual blood is dripped onto the longitudinal and lateral center R1 of the absorbent core 11, where the wearer's excretory opening (vaginal opening) comes into contact. The amount of artificial menstrual blood dripped was set to 10 ml, which is the average amount discharged into the napkin 1 as a result of the applicant's research.

Unlike this embodiment, in napkins in which the thickness of the central portion R1 is thicker after the menstrual blood drop test, unevenness is more likely to form on the skin side after absorbing menstrual blood. This is thought to be because, compared to when the space between the water-retentive fibers becomes smaller and the thickness becomes thinner due to menstrual blood absorption, when the water-retentive fibers widen and the superabsorbent polymer swells due to menstrual blood absorption, the way the thickness changes (how it swells) is more likely to vary due to various causes (such as the distribution of the constituent materials of the absorbent core 11 and the degree of diffusion of menstrual blood). It is also thought that as the thickness increases, unevenness (thickness difference) also increases.

In contrast, in the napkin 1 of this embodiment, the swelling of the central portion R1 after the menstrual blood drop test is suppressed, and the thickness is reduced. Therefore, even after absorbing menstrual blood, it is possible to avoid the formation of unevenness on the skin-side surface of the napkin 1 at the position where it contacts the excretory opening and its surrounding area. This makes it easier for the napkin 1 to maintain a state in which it is in close contact with the wearer's excretory opening and its surrounding area. As a result, it is possible to suppress leakage of menstrual blood through gaps that occur between the napkin and the wearer.

Here, the method of the "menstrual blood drop test" will be explained.
(1) First, the side seam 2 of the shorts-type napkin 1 to be measured is torn, and the napkin 1 is laid out and stretched, and then fixed with the skin side facing up (see FIG. 2).
(2) Next, a center position P1 (see FIG. 5) is determined as the intersection of a line that divides the absorbent core 11 in half at its maximum length in the longitudinal direction and a line that divides the absorbent core 11 in half at its maximum width in the lateral direction. A circular region R1 having a diameter of 8 cm and centered at the center position P1 is determined as the longitudinal and lateral central portion R1 of the absorbent core 11.
(3) Next, the thickness of the entire napkin 1 is measured at five points in the central region R1, and the average value of the thicknesses at these five points is calculated. This average value is the thickness of the central region R1 of the shorts-type napkin 1 before the menstrual blood dropping test.
(4) Next, a cylindrical jig 40 (outer diameter 8 cm, inner diameter 7 cm, thickness (outer radius - inner radius) 0.5 cm, weight 200 g) is placed in the center R1. 10 ml of artificial menstrual blood is dropped inside the jig 40, and after the artificial menstrual blood permeates the absorbent body, the jig 40 is removed and left for 1 hour.
(5) After the artificial menstrual blood is dripped and left for one hour, the thickness of the entire napkin 1 is measured at five points within the inner (hollow) region of the central portion R1 where the jig 40 was placed, and the average value of the thicknesses at these five points is calculated. This average value is the thickness of the central portion R1 of the shorts-type napkin 1 after the menstrual blood dripping test, and is then compared with the thickness before the test.

The thickness of the napkin 1 is measured, for example, using a spring-loaded thickness gauge (Peacock JB) manufactured by Ozaki Manufacturing Co., Ltd., or an equivalent device (the pressure during measurement is determined by the jig of the gauge). When the napkin 1 has a compressed portion (embossed) that is partially compressed in the planar direction, the thickness of the non-compressed portion is measured.
The artificial menstrual blood is prepared by adding 80 g of glycerin, 8 g of sodium carboxymethylcellulose, 10 g of sodium chloride, 4 g of sodium bicarbonate, 8 g of Red No. 102, 2 g of Red No. 2, and 2 g of Yellow No. 5 to 1 L of ion-exchanged water and thoroughly stirring the mixture.

Shorts-type napkin samples (Examples A to D, Comparative Example A) were actually prepared and subjected to a menstrual blood drip test. Table 1 shows the results of the menstrual blood drip test for the shorts-type napkin 1 of this embodiment (Examples A to D) and Comparative Example A.
As shown in Table 1, the absorbent core 11 of each sample had the following configuration: Example A did not contain SAP (super absorbent polymer) in the pulp fibers (basis weight 145 g/m ² ), Example B contained SAP in the pulp fibers (basis weight 145 g/m ² ) at a total weight of 1.3 g and a basis weight of 20.4 g/m ² , Example C contained SAP in the pulp fibers (basis weight 145 g/m ² ) at a total weight of 1.95 g and a basis weight of 30.6 g/m ² , Example D contained SAP in the pulp fibers (basis weight 145 g/m ² ) at a total weight of 2.6 g and a basis weight of 40.8 g/m ² , and Comparative Example A contained SAP in the pulp fibers (basis weight 145 g/m ² ) at a total weight of 8.5 g and a basis weight of 133.4 g/m ² .
The top sheet 11 is made of hydrophilic air-seal nonwoven fabric (basis weight 25 g/ ^m2 ), the core wrap sheet 15 is made of tissue (basis weight 15 g/ ^m2 ), the back sheet 13 is made of breathable resin film (basis weight 20 g/ ^m2 ), and the side sheets are made of hydrophobic SMS nonwoven fabric (basis weight 15 g/ ^m2 ).

From the results in Table 1, it was found that in Examples A to D, the thickness after the menstrual blood dropping test was smaller than the thickness before the test. It was also found that as the basis weight of the SAP contained in the absorbent core 11 decreases, the rate at which the thickness decreases also tends to increase (the value of (thickness after dropping)/(thickness before dropping) becomes smaller).

Table 2 shows the results of the reference test of the menstrual blood dripping test. As a reference test, a shorts-type napkin having an absorbent core (pulp fiber, basis weight 145 g/ ^m2 ) containing no SAP was manufactured, and the absorbent core of Reference Example A, which was subjected to the menstrual blood dripping test, was flat-pressed (a process of uniformly compressing the entire surface of the absorbent core) during manufacture. The absorbent core of Reference Example B was an absorbent core that was not flat-pressed, but was left as it was after the pulp fibers layered in the mold were released.

The results in Table 2 show that in Reference Example A, where the absorbent core was flat-pressed, the thickness after the menstrual blood drop test was greater than the thickness before the test. On the other hand, in Reference Example B, where the absorbent core was not flat-pressed, the thickness after the menstrual blood drop test was smaller than the thickness before the test. Therefore, it was found that the pressure applied in the thickness direction during the manufacture of the absorbent core also affects the thickness of the absorbent core (napkin 1) after absorbing menstrual blood.

From the above results, by adjusting the amount of SAP contained in the absorbent core 11 and the strength of the pressure applied during the manufacture of the absorbent core 11, it is possible to manufacture the napkin 1 of this embodiment in which the swelling of the central portion R1 of the napkin 1 after absorbing menstrual blood is suppressed.

Furthermore, when the napkin 1 is in an unfolded and stretched state (Figure 5), if a saline solution drop test is conducted in which saline solution is dropped onto the back center portion R2, which is the center portion in the longitudinal and lateral directions of the back region 11C when the absorbent core 11 is divided into three longitudinal portions, it is desirable that the thickness of the back center portion R2 of the shorts-type napkin 1 after the saline solution drop test is smaller than the thickness of the back center portion R2 of the shorts-type napkin 1 before the saline solution drop test.

In the saline solution drip test, a scenario is assumed in which the wearer sweats on the back while sleeping (lying on their back), and saline solution (artificial sweat) is dripped onto the back center R2 of the absorbent core 11, the position where the wearer's back comes into contact. As a result of the applicant's research, the amount of saline solution dripped was set to 30 ml, which is the average amount of sweat produced while sleeping (for 8 hours).

Unlike diapers, which require space for the buttocks to accommodate feces, the napkin 1 is preferably inserted into the groove of the wearer's buttocks, and this can prevent back leakage caused by menstrual blood running down the groove of the buttocks. Therefore, as with the napkin 1 of this embodiment, by preventing the thickness of the back center portion R2 of the napkin 1 from expanding after absorbing sweat (saline solution), the napkin 1 is more likely to maintain a state in which it is in close contact with the groove of the buttocks (a state in which it is inserted). In addition, by reducing the thickness of the back center portion R2 of the napkin 1, it is possible to prevent unevenness from being formed on the skin side of the napkin 1, and therefore it can be said that the napkin 1 is more likely to maintain a state in which it is in close contact with the back side (buttocks) of the wearer. As a result, back leakage caused by menstrual blood running down the groove of the buttocks can be prevented. In particular, back leakage can be prevented even when the buttocks are prone to sweating while sleeping.

Here, we will explain the method of the "saline drop test", focusing mainly on the differences from the menstrual blood drop test.
(1) First, the shorts-type napkin 1 to be measured is laid out and stretched, and fixed with the skin side facing up.
(2) Next, the back region 11C is determined from the regions (11A to 11C) obtained by dividing the absorbent core 11 into three at its maximum length in the longitudinal direction, and a back center position P2 (see FIG. 5) is determined as the intersection of a line dividing the back region 11C in two at its maximum width in the longitudinal direction and a line dividing the back region 11C in two at its maximum width in the left-right direction. A region R2 of a circle having a diameter of 8 cm and centered at the back center position P2 is determined as the back center portion R2 of the back region 11C, which is the center in the longitudinal direction and the left-right direction.
(3) Next, the thickness of the entire napkin 1 is measured at five points in the rear center portion R2, and the average value of the thicknesses at the five points is calculated. This average value is the thickness of the rear center portion R2 of the shorts-type napkin 1 before the saline solution drop test.
(4) Next, a cylindrical jig 40 (same as that used in the menstrual blood drop test) is placed in the back center R2. 30 ml of saline solution is dropped inside the jig 40, and after the saline solution has permeated the absorbent body, the jig 40 is removed and the garment is left for one hour. 0.9% saline solution was used.
(5) After the saline solution is dripped and left for one hour, the thickness of the entire napkin 1 is measured at five points within the inner (hollow) area of the back center portion R2 where the jig 40 was placed, and the average value of the thicknesses at the five points is calculated. This average value is the thickness of the back center portion R2 of the shorts-type napkin 1 after the saline solution drip test. It is then compared with the thickness before the test.

Table 3 shows the results of the saline drop test for the shorts-type napkin 1 of this embodiment (Examples A to D) and Comparative Example A. The saline drop test was conducted on samples (Examples A to D, Comparative Example A) having the same configuration as the shorts-type napkin sample that was subjected to the menstrual blood drop test described above. From the results in Table 3, it was found that in Examples A and B, the thickness after the saline drop test was smaller than the thickness before the test. On the other hand, in Examples C, D, and Comparative Example A, which have a larger basis weight of SAP than Examples A and B, the thickness after the saline drop test was larger than the thickness before the test. As in the menstrual blood drop test, it was found that the smaller the basis weight of the SAP contained in the absorbent core 11, the greater the proportion of thickness reduction (the smaller the value of (thickness after drop)/(thickness before drop)).

Table 4 shows the results of the reference test for the saline solution drip test. A similar test was also conducted for the reference test (a test in which saline solution was dripped onto a shorts-type napkin having an absorbent core that does not contain SAP). As a result, as shown in Table 4, in Reference Example A, in which the absorbent core was flat-pressed, the thickness after the saline solution drip test was greater than the thickness before the test, and in Reference Example B, in which the absorbent core was not flat-pressed, the thickness after the saline solution drip test was smaller than the thickness before the test. Therefore, it was found that the pressure applied in the thickness direction during the manufacture of the absorbent core also affects the thickness of the absorbent core (napkin 1) after absorbing saline solution.

From the above results, by adjusting the amount of SAP contained in the absorbent core 11 and the strength of the pressure applied during the manufacture of the absorbent core 11, a napkin 1 of this embodiment (Example A, Example B) can be obtained that suppresses swelling that occurs in the back part (buttocks) after absorbing sweat.

The absorbent core 11 of this embodiment contains water-retentive fibers, and does not include areas where water-retentive fibers are not present (e.g. areas where only SAP is present). There are no particular limitations on the water-retentive fibers, so long as they are fibers that have the property of absorbing and retaining moisture, and examples of such fibers include cellulosic fibers (e.g. pulp fibers, non-wood fibers such as cotton and hemp, and regenerated fibers such as rayon).

The absorbent core 11 does not have to contain a superabsorbent polymer (SAP). Superabsorbent polymers swell when they absorb liquid. Therefore, by not containing a superabsorbent polymer, unevenness is less likely to form on the skin side of the absorbent core 11 even after absorbing menstrual blood and sweat, making it easier for the napkin 1 to remain in close contact with the wearer, and preventing leakage.

In addition to the above, the absorbent core 11 may contain a superabsorbent polymer. For example, a superabsorbent polymer may be mixed into an aggregate of water-retentive fibers. In this case, the water retention capacity of the absorbent core 11 can be ensured. In addition, since the superabsorbent polymer firmly holds the absorbed liquid, rewetting of the excreted liquid (returning onto the top sheet 12) can be suppressed.

However, the napkin 1 does not need to retain as much water as a diaper.
Therefore, it is preferable that the ratio of the total weight (g) of the superabsorbent polymer contained in the absorbent core 11 to the total weight (g) of the water-retentive fibers contained in the absorbent core 11 (SAP/water-retentive fibers) is 1/5 or less.
By doing so, compared to when the ratio is greater than 1/5, unevenness is less likely to form on the skin side of the napkin 1 even after absorbing excrement, and the napkin 1 is more likely to be maintained in close contact with the wearer.

It is also preferable that the surface sheet 12 has a larger basis weight (g/ ^m2 ) and thickness than the skin side sheets 21, 31, and that the total weight (g) of the superabsorbent polymer contained in the absorbent core 11 is lighter than the total weight (g) of the surface sheet 12 of the napkin 1.
In this case, the feel and cushioning of the top sheet 12 are improved compared to when the basis weight (g/ ^m2 ) and thickness of the top sheet 12 are smaller than those of the skin side sheets 21, 31. This improves the comfort of the top sheet 12 for wearers who have sensitive areas around the vaginal opening during menstruation. Meanwhile, by reducing the total weight of the superabsorbent polymer, the water retention capacity of the absorbent body 10 does not increase unnecessarily, and the total weight of the absorbent body 10 can be reduced. This prevents the absorbent body 10 from sagging due to its own weight, and makes it easier for the napkin 1 to maintain its close contact with the wearer.

The thickness of the skin side sheets 21, 31 and the top sheet 12 can be compared by known methods, for example, by the same method as that used to measure the thickness of the napkin 1 in the menstrual blood drop test described above. It is also advisable to cut out multiple samples from each of the target sheets (21, 31, 12) separated from the napkin 1, and compare the average basis weight and average thickness of the multiple samples for each sheet.

Furthermore, when the absorbent core 11 contains a superabsorbent polymer, it is preferable that the combined weight (g) of the core wrap sheet 15 and the absorbent core 11 (i.e., the water-retaining fibers and superabsorbent polymer present in the core wrap sheet 15) is lighter than half the weight (g) of the entire shorts-type napkin 1.
By doing so, the weight of the materials (core wrap sheet 15 and absorbent core 11) that affect the water retention capacity of the absorbent body 10 is reduced, and the water retention capacity of the absorbent body 10 is not unnecessarily large, and the total weight of the absorbent body 10 can be reduced. Therefore, sagging of the absorbent body 10 due to its own weight can be suppressed. Therefore, the napkin 1 can be easily maintained in close contact with the wearer.

Furthermore, when the absorbent core 11 contains a superabsorbent polymer (SAP), it is preferable that the water retention capacity of the absorbent body 10 is less than 150 g and the total weight of the absorbent core 11 (excluding the core wrap sheet 15) is 20 g or less.
This prevents the water retention capacity of the absorbent core 11 from becoming unnecessarily large, and allows the total weight of the absorbent body 10 to be reduced. Furthermore, compared to when the total weight of the absorbent core 11 is greater than 20 g, sagging of the absorbent body 10 due to its own weight can be suppressed, and the napkin 1 can be more easily maintained in close contact with the wearer.

FIG. 6 is an explanatory diagram of the constricted portion 11D of the absorbent core 11. As shown in FIG.
In the crotch portion 1B (the region from the lower end of the ventral waist portion 20 to the lower end of the dorsal waist portion 30) of the shorts-type napkin 1, which is located under the wearer's crotch when worn, it is preferable that the absorbent core 11 has a constricted portion 11D that is constricted on the inside in the left-right direction.
This makes it less stiff when the wearer pinches the constricted portion 11D of the absorbent core 11 between the legs (reducing the feeling of a foreign object), improving comfort. Also, the width of the absorbent core 11 is wider behind the constricted portion 11D. This provides a sense of security to users who are worried about rear leakage when sleeping, etc.

Furthermore, when the shorts-type napkin 1 is in an unfolded and extended state (see Figure 6), it is preferable that when the absorbent core 11 is divided into three in the longitudinal direction, the back region 11C has a greater total weight (g) of water-retentive fibers than the central region 11B.
By doing so, while menstrual blood tends to flow to the rear side during sleep, the many water-retentive fibers in the rear region 11C can absorb the menstrual blood well and prevent rear leakage. In addition, the many water-retentive fibers in the rear region 11C can absorb sweat from the rear side, which is more likely to sweat than the ventral side. This can prevent the wearer from feeling uncomfortable or getting a skin rash due to sweat.

Even if the basis weight of the water-retentive fiber is constant between the central region 11B and the rear region 11C of the absorbent core 11, the rear region 11C has a larger planar area (width) of the absorbent core 11, so the total weight of the water-retentive fiber can be increased. Furthermore, the basis weight of the water-retentive fiber may be greater in the rear region 11C than in the central region 11B.

Furthermore, when the absorbent core 11 has a constricted portion 11D, as shown in FIG. 6, the constricted portion 11D and the region 11E adjacent to the constricted portion 11D on both the left and right outer sides may contain a superabsorbent polymer. It is preferable that the total weight (g) of the superabsorbent polymer in the adjacent region 11E is smaller than that of the constricted portion 11D. The region 11E adjacent to the constricted portion 11D overlaps with the constricted portion 11D in the longitudinal direction, and is the region from the left and right side ends of the absorbent core 11 to the side ends of the absorbent body 10.

The presence of the superabsorbent polymer in the constricted portion 11D, which is the portion that the wearer's excretory opening contacts, allows menstrual blood to be firmly absorbed and retained, suppressing rewetting and leakage. In addition, since the region 11E adjacent to the constricted portion 11D is a portion located around the wearer's legs, the presence of the superabsorbent polymer there allows sweat around the legs to be absorbed, improving comfort and suppressing skin rashes. On the other hand, it is preferable that the total weight (g) of the superabsorbent polymer in the region 11E adjacent to one side of the constricted portion 11D in the left-right direction and the total weight (g) of the superabsorbent polymer in the region 11E adjacent to the other side in the left-right direction be less than the total weight (g) of the superabsorbent polymer in the region 11E. This can suppress swelling caused by the superabsorbent polymer in the adjacent region 11E absorbing sweat, reducing discomfort (foreign body sensation) around the legs.

Furthermore, when the absorbent core 11 has a superabsorbent polymer and a constricted portion 11D, it is preferable that the following is satisfied. The constricted portion 11D has a narrowest portion 11F that has the shortest length in the left-right direction, and it is preferable that a portion 11G of the absorbent core 11 located outside the narrowest portion 11F in the left-right direction has a lower basis weight (average basis weight) of the superabsorbent polymer than a portion that overlaps with the narrowest portion 11F in the left-right direction (an inner portion of 11G).

By doing so, the basis weight of the superabsorbent polymer is increased in the area that overlaps with the narrowest part 11F in the left-right direction and where the wearer's excretory opening comes into contact, so menstrual blood is firmly absorbed and retained, and rewetting and leakage can be suppressed. Also, in the area 11G (the four corners of the absorbent core 11) outside the narrowest part 11F, the formation of unevenness due to liquid absorption can be avoided, and the four corners (11G) of the absorbent core 11 can stably support the absorbent core 11 inside it, making it easier for the absorbent core 11 inside it to remain in close contact with the wearer.

The weight and basis weight of each of the materials described above (water-retentive fibers, superabsorbent polymers, etc.) can be compared using well-known methods.

Fig. 7 is a side view of the shorts-type napkin 1 in a folded state. The shorts-type napkin 1 is generally often stored in an individual wrapping body or package with the portions of the waistline portion (20, 30) that extend outward in both the left and right directions from the absorbent main body 10 folded. Therefore, as shown in Fig. 7, it is preferable that the top sheet 12 is visible from the leg openings LH when the portions of the ventral waistline portion 20 and the dorsal waistline portion 30 located outward in the left and right directions from the absorbent main body 10 are folded in the left and right directions with the ventral side facing inward. The top sheet 12 is the sheet that is located closest to the skin at least in the center of the absorbent main body 10 in the left and right directions and the longitudinal direction.

In other words, it is preferable that the leg openings LH are not covered by the back waist portion 30 (particularly the crotch side portion 30B covering the buttocks), and the inside of the napkin 1 (top sheet 12) is visible from the outside. This allows the inside of the napkin 1 to communicate with the outside via the leg openings LH, making it difficult for moisture to build up inside the napkin 1 before use. In addition, an air passage that connects a pair of leg openings LH in the left and right directions is easily formed, making it difficult for moisture to build up inside the napkin 1 before use. This ensures a comfortable feeling when the wearer puts on the napkin 1.

<<Panties-type napkin packaging body 50>>
Fig. 8 is a front view of a package 50 of shorts-type napkins 1. Figs. 9A and 9B are front views of packages 60, 70 of shorts-type napkins 1 in modified examples. It is preferable that one or more shorts-type napkins 1 are packaged in a package 51. This makes it easy for the user to carry the shorts-type napkins 1 when going out and allows them to be stored hygienically.

In this embodiment, the packaging body 50 is exemplified by folding the packaging material 51, which is rectangular in the unfolded state, into thirds (twice) in the longitudinal direction while enclosing the shorts-type napkin 1. As shown in FIG. 7, the shorts-type napkin 1 may be encased in the packaging material 50 with the waist portion (20, 30) extending outward in the lateral direction from the absorbent body 10 folded inward in the lateral direction, or further folded in half in the vertical direction. The packaging body 50 has a vertical direction and a horizontal direction that are perpendicular to each other, and the longitudinal direction of the packaging material 51 (rectangle) corresponds to the vertical direction, and the short side direction of the packaging material 51 (rectangle) corresponds to the horizontal direction. At a pair of side ends in the lateral direction, a plurality of joints 52 are provided in which the opposing packaging materials 51 are intermittently joined. Examples of the joining method at the joints 52 include welding and adhesives. Note that it is not necessary to provide intermittent joints 52 on both of the pair of side ends in the horizontal direction, as long as intermittent joints 52 are provided on at least one side.

In the above-mentioned package 50, it is preferable that the left-right direction of the shorts-type napkin 1 contained in the packaging material 51 is aligned with the horizontal direction of the package 50. In this way, inside the package 50, a pair of leg openings LH located on both sides of the left-right direction of the napkin 1 are aligned horizontally (left-right) with the intermittent joints 52 of the package 50. Therefore, an air passage is formed that connects the outside and inside of the package 50 and the inside of the napkin 1. Specifically, the air passage passes from the outside of the package 50 through the gaps between the intermittent joints 52 (non-jointed parts), through the leg openings LH of the napkin 1, through the inside of the napkin 1, and further through the joints 52 on the opposite side to the outside of the package 50. Therefore, moisture is less likely to accumulate inside the napkin 1 before use, and a comfortable feeling is ensured when the wearer puts on the napkin 1.

However, the packaging form of the napkin 1 with the packaging material is not particularly limited. For example, as shown in Fig. 9A, a joint (welded part) 63 extending continuously in the vertical direction may be provided at one side end in the horizontal direction of a tubular packaging material 61 extending in the horizontal direction. Then, the napkin 1 may be inserted into the bag-shaped packaging material 61 with a bottom (welded part 63) formed therein, and a plurality of joints 62 may be provided by intermittently joining the opposing packaging materials 61 at the side end on the opposite side in the horizontal direction.
Also, for example, as shown in FIG. 9B , an intermittent joint 72 may be provided at one lateral side end of a tubular bag material 71 whose back surface (not shown) has been joined using a pillow packaging machine, and after the napkin 1 is inserted, an intermittent joint 72 may also be provided at the opposite lateral side end.
9A and 9B, there is no opening end of the packaging material 51 as in the case where the packaging material 51 is folded in three as shown in Fig. 8. Therefore, it is preferable to provide perforations 64, 73 in the packaging material 60, 70, which makes it easier for the user to remove the napkin 1 from the packaging material 60, 70. The positions of the perforations 64, 73 are not limited to those shown in the drawings.

In addition, in Fig. 8, in a package 50 in which intermittent joints 52 are provided at a pair of side ends in the horizontal direction, the left-right direction of the napkin 1 runs along the horizontal direction of the package 50. However, conversely, as shown in Figs. 9A and 9B, in packages 60, 70 in which opposing packaging materials 61, 71 are intermittently joined at least one of a pair of side ends in the horizontal direction, the left-right direction of the napkin 1 may run along the vertical direction.

In this case, the pair of leg openings LH located on both left and right sides of the napkin 1 and the intermittent joints 62, 72 of the packaging bodies 60, 70 are not aligned in the same direction. Therefore, outside air that enters the packaging bodies 60, 70 through the intermittent joints 62, 72 is less likely to pass through the leg openings LH of the napkin 1 and is less likely to come into contact with the inside of the napkin 1 (the skin side). Therefore, the napkin 1 can be stored hygienically until the packaging bodies 60, 70 are opened.

===Other embodiments===
Although the embodiment of the present invention has been described above, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. Furthermore, the present invention may be modified or improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

For example, the thickness of the central portion R1 of the shorts-type napkin 1 after the menstrual blood drop test is smaller than the thickness of the central portion R1 of the shorts-type napkin 1 before the menstrual blood drop test, but the thickness of the back central portion R2 of the shorts-type napkin 1 after the saline solution drop test may be greater than or equal to the thickness of the back central portion R2 of the shorts-type napkin 1 before the saline solution drop test (Examples C and D in Table 3).

On the other hand, the thickness of the central portion R1 of the shorts-type napkin 1 after the menstrual blood drop test is greater than or equal to the thickness of the central portion R1 of the shorts-type napkin 1 before the menstrual blood drop test, but the thickness of the back central portion R2 of the shorts-type napkin 1 after the saline solution drop test is smaller than the thickness of the back central portion R2 of the shorts-type napkin 1 before the saline solution drop test may be the same.

1. Shorts-type napkins,
2 side joint, 3 leak-proof wall,
10 Absorbent body,
11 absorbent core, 12 top sheet, 13 back sheet,
14 Side sheet, 15 Core wrap sheet,
16 Leak-proof wall elastic member,
20 ventral waist portion,
21 skin side sheet, 22 non-skin side sheet,
23 waist elastic member, 24 cover sheet,
30 back waist portion,
31 skin side sheet, 32 non-skin side sheet,
33 waist elastic member, 34 cover sheet,
35 inclined elastic member,
40 Jig,
50. Shorts-type napkin packaging;
60 Shorts-type napkin packaging,
70 Shorts-type napkin packaging,

Claims (13)

1. an absorbent body having an absorbent core including water-retentive fibers;
   A ventral waist portion;
   A back side waist portion configured as a separate member from the ventral side waist portion;
   A shorts-type napkin having
   In the deployed and extended state,
   The substrate has a longitudinal direction, a left-right direction, and a thickness direction which are perpendicular to each other,
   When a menstrual blood drop test was conducted in which artificial menstrual blood was dropped onto the central portion of the absorbent core in the longitudinal direction and the left-right direction,
   The thickness of the central portion of the shorts-type napkin after the menstrual blood drop test is
   A shorts-type napkin, characterized in that the thickness of the shorts-type napkin at the central portion is smaller than the thickness of the shorts-type napkin at the central portion before the menstrual blood drop test is conducted.
2. an absorbent body having an absorbent core including water-retentive fibers;
   A ventral waist portion;
   A back side waist portion configured as a separate member from the ventral side waist portion;
   A shorts-type napkin having
   In the deployed and extended state,
   The substrate has a longitudinal direction, a left-right direction, and a thickness direction which are perpendicular to each other,
   When the absorbent core is divided into three parts in the longitudinal direction, a saline solution drop test is performed in which physiological saline solution is dropped on a central part of the back side, which is a central part in the longitudinal direction and the left-right direction, of the back side region.
   The thickness of the back center part of the shorts-type napkin after the saline solution drop test is
   A shorts-type napkin, characterized in that the thickness is smaller than the thickness of the central portion of the back side of the shorts-type napkin before the saline solution drop test is performed.
3. an absorbent body having an absorbent core including water-retentive fibers;
   A ventral waist portion;
   A back side waist portion configured as a separate member from the ventral side waist portion;
   A shorts-type napkin having
   In the deployed and extended state,
   The substrate has a longitudinal direction, a left-right direction, and a thickness direction which are perpendicular to each other,
   When a menstrual blood drop test was conducted in which artificial menstrual blood was dropped onto the central portion of the absorbent core in the longitudinal direction and the left-right direction,
   The thickness of the central portion of the shorts-type napkin after the menstrual blood drop test is
   the thickness of the central portion of the shorts-type napkin before the menstrual blood drop test is conducted;
   When the absorbent core is divided into three parts in the longitudinal direction, a saline solution drop test is performed in which physiological saline solution is dropped on a central part of the back side, which is a central part in the longitudinal direction and the left-right direction, of the back side region.
   The thickness of the back center part of the shorts-type napkin after the saline solution drop test is
   A shorts-type napkin, characterized in that the thickness is smaller than the thickness of the central portion of the back side of the shorts-type napkin before the saline solution drop test is performed.
4. A shorts-type napkin according to any one of claims 1 to 3,
   A shorts-type napkin, characterized in that in a developed and stretched state, in a region between said ventral waist portion and said rear waist portion, no elastic members are present outside said absorbent main body in the left-right direction.
5. A shorts-type napkin according to any one of claims 1 to 3,
   the absorbent core has a constricted portion constricted on the inside in the left-right direction in a crotch portion of the shorts-type napkin that is located under the crotch of a wearer when worn,
   A shorts-type napkin characterized in that, in an expanded and extended state, the absorbent core is divided into three in the longitudinal direction, and the total weight of the water-retentive fibers is greater in the back region than in the central region.
6. A shorts-type napkin according to any one of claims 1 to 3,
   the absorbent core has a constricted portion constricted on the inside in the left-right direction in a crotch portion of the shorts-type napkin that is located under the crotch of a wearer when worn,
   the constricted portion and the regions adjacent to the constricted portion and both outer sides in the left-right direction contain a highly water-absorbent polymer;
   A shorts-type napkin, characterized in that the total weight of the superabsorbent polymer in the adjacent region is smaller than that in the waisted portion.
7. A shorts-type napkin according to any one of claims 1 to 3,
   A shorts-type napkin, wherein the absorbent core does not contain a superabsorbent polymer.
8. A shorts-type napkin according to any one of claims 1 to 3,
   The absorbent body has a liquid-permeable top sheet,
   This shorts-type napkin is characterized in that when the portions of the ventral waistband and the dorsal waistband located outside the absorbent body in the left-right direction are folded in the left-right direction with the ventral side inward, the top sheet is visible through the leg openings.
9. A shorts-type napkin according to any one of claims 1 to 3,
   the absorbent core comprises a highly absorbent polymer, and has a constricted portion constricted on the inside in the left-right direction in a crotch portion of the shorts-type napkin that is located under the crotch of a wearer when worn,
   The constricted portion has a narrowest portion having a shortest length in the left-right direction,
   A shorts-type napkin, characterized in that the basis weight of the superabsorbent polymer is lower in a portion of the absorbent core that is located outside the narrowest portion in the left-right direction than in a portion that overlaps the narrowest portion in the left-right direction.
10. A shorts-type napkin according to any one of claims 1 to 3,
    The absorbent body has a liquid-permeable top sheet,
    The ventral waist portion and the back waist portion each have a skin side sheet, a non-skin side sheet, and a waist elastic member arranged therebetween that is stretchable in the left-right direction,
    The absorbent core comprises a superabsorbent polymer;
    The shorts-type napkin is characterized in that the surface sheet has a larger basis weight and thickness than the skin side sheet, and the total weight of the highly absorbent polymer contained in the absorbent core is lighter than the total weight of the surface sheet.
11. A shorts-type napkin according to any one of claims 1 to 3,
    The absorbent core has a surface covered with a liquid-permeable core wrap sheet and has a highly water-absorbent polymer;
    A shorts-type napkin, characterized in that the combined weight of said core wrap sheet and said absorbent core is less than half the weight of said shorts-type napkin.
12. A package for a shorts-type napkin comprising the shorts-type napkin according to any one of claims 1 to 3 and a packaging material,
    having a vertical direction and a horizontal direction perpendicular to each other,
    the packaging material is folded to enclose the shorts-type napkin therein;
    At least one of a pair of side ends in the lateral direction is intermittently joined to the opposing packaging materials,
    A package of shorts-type napkins, characterized in that the left-right direction of the shorts-type napkins contained in the packaging material is aligned with the lateral direction.
13. A package for a shorts-type napkin comprising the shorts-type napkin according to any one of claims 1 to 3 and a packaging material,
    having a vertical direction and a horizontal direction perpendicular to each other,
    the packaging material is folded to enclose the shorts-type napkin therein;
    At least one of a pair of side ends in the lateral direction is intermittently joined to the opposing packaging materials,
    A package of shorts-type napkins, characterized in that the left-right direction of the shorts-type napkins contained in the packaging material is aligned with the vertical direction.

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