CN113924073A

CN113924073A - Underpants-type absorbent article

Info

Publication number: CN113924073A
Application number: CN202080038122.3A
Authority: CN
Inventors: 笹山贤一; 村上圭; 永山唯; 近藤大贵
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2019-05-29
Filing date: 2020-03-26
Publication date: 2022-01-11
Also published as: JP7350518B2; JP2020192123A; WO2020241024A1

Abstract

The non-stretchable sheet (213) and the stretchable sheet (215) are bonded to each other in the front-rear direction by a plurality of bonding sections (25), and in an extended state, the ratio of the area of a low area ratio region (X) having a ratio of the area of the bonding section per unit area of a predetermined value to the area of the bonding section per unit area is larger than the ratio of the area of a high area ratio region (Y) having a low area ratio region (Y) having a ratio of the area of the bonding section per unit area of a lower area ratio region (F1) to the area of the bonding section per unit area of the non-stretchable sheet (215), and when a region of one waist portion where the low area ratio region (X) and the absorbent core do not overlap is defined as a first region (F1), a region where the low area ratio region and the absorbent core (11) overlap is defined as a second region (F2), and a region where the high area ratio region (Y) and the absorbent core overlap is defined as a third region (F3), the second region (F2) is provided between the first region (F1) and the third region (F3) in the vertical direction at the center in the left-right direction.

Description

Underpants-type absorbent article

Technical Field

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

Background

As a pants-type absorbent article, a pants-type disposable diaper is known. For example, patent document 1 discloses a pant-type diaper 10 having an outer cover 30, a waist elastic member 33, and an absorbent body 20 provided with an absorbent core 22. The absorbent body 20 (absorbent core 22) is joined to the outer package 30 so as to extend from the front side portion a to the back side portion B along the longitudinal direction of the diaper 10.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-255558

Disclosure of Invention

Problems to be solved by the invention

In the diaper 10 of patent document 1, the force based on the expansion and contraction in the width direction of the waist elastic member 33 is reduced by the overlapping and joining of the outer cover 30 and the absorbent core 22. Therefore, since a difference in rigidity occurs between the region where the absorbent core 22 is superposed and the region where the absorbent core 22 is not superposed, and there is also a difference in elastic modulus between the exterior section 30 between the region where the absorbent core 22 is superposed and the region where the absorbent core is not superposed, there is a possibility that the shape of the body and the following ability to the body movement are different at the upper end of the absorbent core 22 during wearing, and the wearer may feel uncomfortable.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a pant-type absorbent article that reduces discomfort given to a wearer due to poor conformability between a region where a waist portion and an absorbent core do not overlap and a region where the waist portion and the absorbent core overlap.

Means for solving the problems

The main invention for achieving the above object is a pant-type absorbent article having a vertical direction, a horizontal direction, and a front-back direction intersecting each other, and having: a pair of waist portions; and an absorbent main body including an absorbent core arranged in the vertical direction and bent in the vertical direction at a lower end portion of the vertical direction, wherein at least one of the pair of waist portions includes a non-stretchable sheet and a stretchable sheet stretchable in the horizontal direction, the non-stretchable sheet and the stretchable sheet are welded to each other in the vertical direction by a plurality of welding portions, and in an extended state, a ratio of a low area ratio region having a ratio of an area of the welding portion per unit area of a predetermined value to an area of the welding portion per unit area is larger than a ratio of an area of a high area ratio region of the low area ratio region, a region of the one waist portion where the low area ratio region does not overlap with the absorbent core is set as a first region, and a region of the low area ratio region overlapping with the absorbent core is set as a second region, when a region where the high area ratio region overlaps with the absorbent core is set as a third region, the second region is provided between the first region and the third region in the vertical direction at a central portion in the left-right direction.

Other features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the second region provided between the first region and the third region having a large difference in the following performance when worn can easily absorb the difference in the following performance when worn between the first region and the third region, and can reduce the fear of discomfort given to the wearer due to the difference in the following performance when worn between the first region and the third region.

Drawings

Fig. 1 is a perspective view of a pants-type disposable diaper 1.

Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state as viewed from the skin side.

Fig. 3 is a schematic sectional view taken along line I-I of fig. 2.

Fig. 4A of fig. 4 is a schematic plan view of the absorbent body 10 in an expanded and stretched state as viewed from the skin side. Fig. 4B is a sectional view a-a of fig. 4A.

Fig. 5 is a schematic plan view of the diaper 1 in an unfolded and stretched state, and is a diagram illustrating the positional relationship between various stretchable regions and the absorbent core 11.

Fig. 6 is a plan view of the absorbent core 11 viewed from the skin side.

Fig. 7 is a schematic perspective view illustrating deformation of the absorbent core 11 when the diaper 1 is worn.

Fig. 8 is a view for explaining the regions of different sizes of the followability of the diaper 1 in the unfolded and extended state.

Fig. 9 is a view illustrating each welded region of the diaper 1 in an unfolded and extended state.

Detailed Description

At least the following matters will be made clear from the description of the present specification and the drawings.

A pant-type absorbent article having a vertical direction, a horizontal direction, and a front-back direction intersecting each other, comprising: a pair of waist portions; and an absorbent main body including an absorbent core arranged in the vertical direction and bent in the vertical direction at a lower end portion of the vertical direction, wherein at least one of the pair of waist portions includes a non-stretchable sheet and a stretchable sheet stretchable in the horizontal direction, the non-stretchable sheet and the stretchable sheet are welded to each other in the vertical direction by a plurality of welding portions, and in an extended state, a ratio of a low area ratio region having a ratio of an area of the welding portion per unit area of a predetermined value to an area of the welding portion per unit area is larger than a ratio of an area of a high area ratio region of the low area ratio region, a region of the one waist portion where the low area ratio region does not overlap with the absorbent core is set as a first region, and a region of the low area ratio region overlapping with the absorbent core is set as a second region, when a region where the high area ratio region overlaps with the absorbent core is set as a third region, the second region is provided between the first region and the third region in the vertical direction at a central portion in the left-right direction.

According to such a pant-type absorbent article, the second region provided between the first region and the third region, which has a large difference in the following performance when worn, can easily absorb the difference in the following performance when worn between the first region and the third region, and can reduce the fear of discomfort given to the wearer due to the difference in the following performance when worn between the first region and the third region.

In the pant-type absorbent article, the absorbent core preferably has a low basis weight region in the second region, the low basis weight region having a lower average basis weight than the surrounding region.

According to such a pant-type absorbent article, since the rigidity of the second region can be reduced by the low basis weight region provided in the second region, the second region can be made to have greater conformability when worn than the third region, and a difference in conformability between the first region and the third region when worn can be easily buffered.

In the pant-type absorbent article, it is preferable that the absorbent core also has a low basis weight region having a lower average basis weight than the surroundings in the third region.

According to such a pant-type absorbent article, the rigidity of the absorbent core on one waist region side can be reduced as a whole by the low basis weight regions provided in the second region and the third region, and therefore the difference in followability when worn between the first region and the third region can be further reduced.

In the pant-type absorbent article, it is preferable that a plurality of low basis weight regions provided in the third region are provided at intervals in the left-right direction, and the number of low basis weight regions provided in an upper end portion of the third region is larger than the number of low basis weight regions provided in a lower end portion of the third region in the left-right direction.

According to such a pant-type absorbent article, the rigidity of the upper end portion of the third region near the second region is made lower than the rigidity of the lower end portion, so that the followability is easily reduced stepwise from the second region toward the lower end portion of the third region, and the discomfort to the wearer due to the difference in followability when worn is easily reduced.

In the pant-type absorbent article, the low basis weight regions preferably have upper and lower low basis weight regions having a first length in the up-down direction and left and right low basis weight regions having a second length in the left-right direction.

According to such a pant-type absorbent article, the upper and lower low basis weight regions and the left and right low basis weight regions are likely to become bending starting points, and the absorbent core is likely to deform in the upper and lower directions and the left and right directions, and is likely to have a shape corresponding to the body and exercise of the wearer.

In the pant-type absorbent article, it is preferable that, regarding a region overlapping the third region in the left-right direction, a fourth region where the high area ratio region and the absorbent core do not overlap is adjacent to the third region from outside of the third region in the left-right direction, and the first region is adjacent to the first region from outside of the fourth region in the left-right direction.

According to such a pant-type absorbent article, the fourth region easily absorbs the difference in the following performance between the first region and the third region in the region overlapping the third region in the left-right direction, and the fear of discomfort to the wearer due to the difference in the left-right direction stress caused by the difference in the following performance between the first region and the third region when worn can be reduced.

In the pant-type absorbent article, the pair of waist portions preferably have the welded portion, the first region, the second region, and the third region, respectively, and a length in the vertical direction of the second region of the back-side waist portion is preferably longer than a length in the vertical direction of the second region of the abdomen-side waist portion at a center in the horizontal direction and in the extended state.

According to such a pant-type absorbent article, since the stress due to the difference in the following performance when the absorbent article is worn tends to concentrate on the back side due to the irregularities of the buttocks and the waist, by providing the second region that absorbs the difference in the following performance when the absorbent article is worn between the first region and the third region to be large, the stress due to the difference in the circumferential principal force between the first region and the third region can be reduced.

Detailed description of the preferred embodiments

Hereinafter, as the "pant-type absorbent article" of the present invention, a pant-type disposable diaper 1 for adult use (hereinafter, also referred to as "diaper 1") will be described as an example of an embodiment. However, the pant-type absorbent article of the present invention can be used as, for example, a disposable diaper for children, a sanitary product (pants-type sanitary napkin), or the like.

[ integral Structure of diaper 1 ]

Fig. 1 is a schematic perspective view of a diaper 1. Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state as viewed from the skin side. Fig. 3 is a schematic sectional view taken along line I-I of fig. 2. Fig. 4A is a schematic plan view of the absorbent body 10 in an expanded and stretched state as viewed from the skin side. C-C in FIG. 2 etc. indicates the center in the left-right direction. Fig. 4B is a sectional view a-a of fig. 4A. In fig. 4B, a low basis weight region 30 (described later) provided in the absorbent core 11 is not shown for simplicity of explanation. The "extended state" of the diaper 1 is a state in which the diaper 1 is extended without wrinkles, and is a state in which the dimensions of each member (for example, an exterior portion 20 described later) constituting the diaper 1 are extended to a length that matches or is close to the dimensions of the member alone. The "natural state" is defined as follows. First, after the diaper 1 packaged as a product is taken out from the package, the end portions of the diaper 1 in the left-right direction are stretched to both outer sides in the left-right direction, and are extended to lengths corresponding to or close to the dimensions of the respective members alone. After the extended state is continued for 15 seconds, the diaper 1 is released from the extended state and placed on a flat surface such as a table. Then, the state in which 5 minutes has elapsed with the diaper 1 placed on the flat surface is the natural state of the diaper 1. In fig. 4 to 9, the absorbent core 11, the low basis weight region 30, and the like are not visually recognized from the appearance, but are indicated by solid lines for convenience.

The diaper 1 has a vertical direction, a horizontal direction, and a front-rear direction intersecting each other, and has a thickness direction in which each member is laminated as shown in fig. 3. In the vertical direction, the side to be the waist side of the wearer is defined as the upper side, and the side to be the crotch side of the wearer is defined as the lower side. In the front-rear direction, the side that becomes the abdominal side of the wearer is referred to as the front side, and the side that becomes the back side of the wearer is referred to as the back side. In the thickness direction, the side that contacts the body of the wearer is referred to as the skin side, and the opposite side is referred to as the non-skin side. In the developed state of fig. 2, the diaper 1 has a longitudinal direction and a width direction intersecting each other. The longitudinal direction is a direction along the vertical direction, and the width direction is the same direction as the horizontal direction.

The diaper 1 has an absorbent body 10 having a rectangular shape in a plan view, and an exterior portion 20 positioned on the non-skin side of the absorbent body 10. The exterior 20 includes: an abdomen-side exterior portion (also referred to as "abdomen-side waist portion") 21 located on the front side in the front-rear direction of fig. 1; a back-side exterior portion (also referred to as "back-side waistline portion") 22 located on the back side in the front-back direction; and a crotch outer cover 23 connecting them. The above members adjacent in the thickness direction are joined by an adhesive or the like.

The abdomen-side exterior portion 21 is located at one end side in the longitudinal direction of the absorbent body 10, and the back-side exterior portion 22 is located at the other end side in the longitudinal direction of the absorbent body 10. In the longitudinal direction of the absorbent body 10, the side where the abdomen-side exterior portion 21 is located is defined as the front side, and the side where the back-side exterior portion 22 is located is defined as the rear side. That is, the stomach-side exterior covering 21 is located at the front upper end of the absorbent body 10, and the back-side exterior covering 22 is located at the rear upper end of the absorbent body 10. The crotch member 23 is positioned closer to the skin than the abdomen-side exterior cover 21 and the back-side exterior cover 22.

In the diaper 1 of the present embodiment, the exterior portion 20 is constituted by 3 members, but is not limited thereto. For example, the abdomen-side outer cover 21, the back-side outer cover 22, and the crotch portion 23 may be 1 member. Further, a structure in which a member different from the outer cover 20 is further stacked on the non-skin side of the outer cover 20 may be adopted without the crotch portion 23.

In the diaper 1 in the developed state shown in fig. 2, the absorbent body 10 is folded in two at a predetermined position CL in the longitudinal direction, and both left and right side portions of the abdomen-side outer cover 21 and both left and right side portions of the back-side outer cover 22 are joined by welding or the like, thereby forming a pant-like shape shown in fig. 1. That is, the longitudinal direction of the absorbent body 10 is along the vertical direction of the diaper 1, and the abdomen-side outer cover 21 and the back-side outer cover 22 are connected in a loop to form the waist opening 1a and the pair of leg openings 1 b. Hereinafter, a region where the ventral-side exterior portion 21 and the dorsal-side exterior portion 22 are joined is referred to as an end joining region 24.

In the present description, the portion of the absorbent body 10 (absorbent core 11) that is bent at the predetermined position CL and is bent to the front side is referred to as the "ventral portion 10F", and the portion that is bent to the rear side is referred to as the "back portion 10R". That is, in the longitudinal direction of fig. 2, a region of the absorbent main body 10 (absorbent core 11) on the front side of the predetermined position CL may be referred to as a "stomach side portion 10F", and a region on the rear side of the predetermined position CL may be referred to as a "back side portion 10R".

The top sheet 12 is a liquid-permeable sheet, and for example, a hydrophilic air-through nonwoven fabric, a spunbond nonwoven fabric, or the like is used. The back sheet 13 has a two-layer structure of a liquid-impermeable sheet 13a and a water-repellent sheet 13b disposed on the non-skin side thereof. For example, a resin film or the like is used as the liquid-impermeable sheet 13a, and a flexible hydrophobic nonwoven fabric or the like is used as the hydrophobic sheet 13 b. Further, the backsheet 13 may be a one-layer structure of the liquid-impermeable sheet 13 a.

Side sheets 14 are provided on both sides of the chassis 13 in the left-right direction. The side sheet 14 extends outward in the left-right direction from both ends 11es, 11es in the left-right direction of the absorbent core 11, and is folded back inward in the left-right direction and toward the skin in the thickness direction with both ends 10es, 10es in the left-right direction of the absorbent main body 10 as folded-back positions, thereby forming 1 pair of leakage preventing wall portions 40. Leakage preventing wall

elastic members

41, 42 made of rubber or the like are fixed to the leakage preventing wall 40 in a state of extending along the longitudinal direction (vertical direction) of the absorbent body 10. The leakage preventing wall

elastic members

41 and 42 are contracted in the longitudinal direction, so that the pair of leakage preventing wall portions 40 rise toward the skin side at both ends in the lateral direction of the absorbent main body 10, and function as leakage preventing walls (leg side gathers) of the diaper 1. The leakage preventing wall 40 may be formed by extending the chassis 13 (liquid-permeable sheet 13b) to the outside in the lateral direction of the absorbent core 11 without providing the side sheet 14.

As shown in fig. 3, each of the abdomen-side outer cover 21 and the back-side outer cover 22 includes a skin-

side sheet

213, 223 positioned on the skin side, a non-skin-

side sheet

214, 224 positioned on the non-skin side, and a

stretchable sheet

215, 225 positioned therebetween and having stretchability at least in the left-right direction of the diaper 1.

The

skin side sheets

213 and 223 and the

non-skin side sheets

214 and 224 are preferably soft sheets, and for example, spunbond nonwoven fabrics, SMS nonwoven fabrics, and the like are used. The

skin side sheets

213 and 223 and the

non-skin side sheets

214 and 224 are non-stretchable sheets having lower stretchability than the

stretchable sheets

215 and 225.

The

stretchable sheets

215 and 225 are, for example, a stretchable nonwoven fabric having a polyurethane elastomer as an elastic thermoplastic elastomer fiber and a polypropylene (PP) as a polyolefin resin as an inelastic thermoplastic resin fiber, and subjected to an appropriate stretching treatment such as gear stretching. The

stretchable sheets

215 and 225 have stretchability in a predetermined direction by the stretching treatment. The stretching treatment may be performed in directions orthogonal to each other, or may be performed only in a predetermined direction. When the stretching treatment is performed only in the predetermined direction, the stretchability in the predetermined direction is exhibited, but the orientation of all the fibers is not limited to the predetermined direction, and therefore, the stretchability is also exhibited in a direction perpendicular to the predetermined direction.

The

skin side sheets

213 and 223, the

non-skin side sheets

214 and 224, and the

stretchable sheets

215 and 225 are joined by a plurality of welding portions 25 (fig. 9) that are scattered. The welded portion 25 is a region to which welding treatment such as ultrasonic welding or thermal welding is applied. Since the sheets are joined to each other by the welded portion, the touch feeling is soft as compared with a case where the sheets are joined by, for example, a cured adhesive. Further, the

stretchable sheets

215 and 225 are contracted between the welded parts 25, and the

skin side sheets

213 and 223 and the

non-skin side sheets

214 and 224 bulge between the welded parts 25 to form wrinkles, so that the skin feel becomes softer, and a soft impression can be visually given to the user. The welded portion 25 will be described in detail later.

With such a configuration, the entire abdomen-side outer cover 21 and the back-side outer cover 22 have stretchability in the lateral direction (and the vertical direction) of the diaper 1. Fig. 5 is a schematic plan view of the diaper 1 in an unfolded and stretched state, and is a diagram illustrating the positional relationship between various stretchable regions and the absorbent core 11. As shown in fig. 5, a region in which the right-and-left directional stretchability is exhibited in the abdomen-side outer cover 21 is referred to as a front stretchable region 21s, and a region in which the right-and-left directional stretchability is exhibited in the back-side outer cover 22 is referred to as a back stretchable region 22s (a mesh portion in fig. 5).

In addition, as the

stretchable sheets

215 and 225, a stretchable film may be used instead of the stretchable nonwoven fabric. However, since the thickness of the stretchable film is substantially uniform, the swelling of the

skin side sheets

213 and 223 and the

non-skin side sheets

214 and 224 between the welded

portions

25a and 25b is likely to be squashed. On the other hand, since the

stretchable sheets

215 and 225 made of a stretchable nonwoven fabric have an increased thickness between the welded

portions

25a and 25b, the

skin side sheets

213 and 223 and the

non-skin side sheets

214 and 224 are less likely to bulge and collapse, and thus softness and beauty of the skin feel can be maintained.

In the abdomen-side exterior portion 21 and the back-side exterior portion 22, a plurality of linear rubber elastic members 26 are arranged in a region along the waist opening 1 a. Similarly, a plurality of leg hole elastic members 27 such as thread rubber are arranged in the region along the leg hole opening 1 b. That is, since the waist and leg circumferences of the diaper 1 are firmly attached to the body of the wearer by the waist elastic member 26 and the leg elastic members 27, the diaper 1 can be prevented from being displaced and leaking from the leg circumferences. On the other hand, the other portions are smoothly fitted to the body of the wearer over the entire surface by the

stretchable sheets

215 and 225, so that the feeling of tightness can be reduced.

The crotch member 23 has a substantially hourglass shape in plan view, curved inward in the lateral direction at the center in the longitudinal direction. As shown in fig. 3, the crotch member 23 includes a skin-side sheet 231 located on the skin side, a non-skin-side sheet 232 located on the non-skin side, and an extensible sheet 233 located therebetween and providing extensibility in the vertical direction of the diaper 1 (the longitudinal direction of the absorbent body 10). These pieces 231 to 233 are joined by a plurality of welding portions (not shown). In the crotch member 23, a region in which stretchability in the vertical direction is exhibited is referred to as a crotch stretch region 23s (see a hatched portion in fig. 5).

By providing this crotch stretch region 23s, the absorbent core 11 can be brought into close contact with the wearer's crotch, and sagging of the diaper 1 can be suppressed even if the weight of the absorbent core 11 increases due to excretion. In addition, a plurality of crotch elastic members 28 are disposed in the crotch member 23 in regions along the leg hole openings 1b, and the crotch member 23 is in close contact with the leg holes of the wearer.

As shown in fig. 3, the absorbent body 10 has an absorbent core 11, a top sheet 12 positioned on the skin side of the absorbent core 11, and a back sheet 13 positioned on the non-skin side of the absorbent core 11.

The absorbent core 11 is a member that absorbs and retains excretory fluid such as urine, and is formed of liquid absorbent fibers such as pulp fibers mixed with a Super Absorbent Polymer (SAP), for example. The absorbent core 11 of the present embodiment has a constricted portion 11c having a laterally narrowed width between the front side end and the rear side end in the longitudinal direction, and has a substantially hourglass shape in plan view as shown in fig. 4A. The absorbent core 11 is formed with a low basis weight region 30, which is a region having a lower basis weight than the surrounding regions. The absorbent core 11 may be covered on the outer peripheral surface with a liquid-permeable sheet such as crepe paper or nonwoven fabric.

The low basis weight region 30(31, 32) can easily deform the absorbent core 11 (absorbent body 10) in accordance with the movement of the wearer's body when the diaper 1 is worn. Fig. 6 is a plan view of the absorbent core 11 viewed from the skin side.

As shown in fig. 6, the absorbent core 11 has a "lower abdominal region 11A" located in the lower abdominal region of the wearer, a "lower crotch region 11B" located in the lower crotch region of the wearer, and a "hip region 11C" located in the hip region of the wearer when worn. In fig. 6, a region overlapping the abdomen-side outer cover 21 is referred to as an abdomen-lower region 11A, a region overlapping the back-side outer cover 22 is referred to as a hip region 11C, and a crotch region 11B is provided therebetween. That is, the lower abdomen portion 11A is a portion located in the abdomen-side portion 10F of the diaper 1, and the hip portion 11C is a portion located in the back-side portion 10R of the diaper 1. The crotch region 11B is a region located at the lower end in the vertical direction of the pant-shaped diaper 1 and is provided across the front side portion 10F and the back side portion 10R across a predetermined position CL.

The low basis weight regions 31 are provided in plurality at intervals in the left-right direction at each of the lower abdomen region 11A, the crotch region 11B, and the hip region 11C. The low basis weight regions 31 include upper and lower low basis weight regions 31h having a predetermined length (first length) dh in the up-down direction and left and right low basis weight regions 31s having a predetermined length (second length) ds in the left-right direction. The length dh of the upper and lower low basis weight regions 31h and the length ds of the left and right low basis weight regions 31s may be arbitrarily set, and may be different lengths without being equal to each other. The 1 low basis weight region 31 does not necessarily have to include both the upper and lower low basis weight regions 31h and the left and right low basis weight regions 31s, and may include either one. The low basis weight region 31 may be provided in an inclined shape such as the lower abdominal region 11A.

The "basis weight" of the absorbent core 11 means the mass (g/m) of the absorbent core 11 (e.g., liquid absorbent fibers mixed with SAP) per unit area²). The comparison of the basis weight of the low basis weight region 30 with the basis weight of the surrounding absorbent core 11 can be performed by a known method. For example, there is a method of performing comparison by visual observation. Further, there is a method of: the target site was cut out from the absorbent core 11 as a sample, the mass of each sample and the area of each sample were measured, and the mass per unit area was calculated and compared.

The absorbent core 11 is easily folded from the low basis weight region 30 due to the difference in rigidity between the low basis weight region 30 and its surroundings. Therefore, when the diaper 1 is worn, the absorbent core 11 is bent from the low basis weight region 31, and is easily deformed in accordance with the irregularities of the wearer's body, and is easily attached to the wearer's body. That is, the upper and lower low basis weight regions 31h and the left and right low basis weight regions 31s are easily folded up and down.

As shown in fig. 6, the absorbent core 11 has a central low basis weight region 32, which is a region in which the basis weight of the absorbent core 11 is lower than the surrounding regions, on the upper side of the lower end (see fig. 1) of the diaper 1 in the vertical direction and on the front side (the stomach-side portion 10F) in the front-rear direction. The central low basis weight region 32 is a substantially rectangular region which is disposed in the vertical direction (longitudinal direction) at the central portion in the horizontal direction of the absorbent core 11, has a lower basis weight of the absorbent core 11 than the periphery, and is longer in the vertical direction than the horizontal direction of the diaper 1. Similarly, the central low basis weight region 32 is also provided on the upper side of the lower end of the diaper 1 in the vertical direction and on the rear side (the back side portion 10R) in the front-rear direction. In the present embodiment, the absorbent core 11 is not present in the central low basis weight region 32. That is, the central low basis weight region 32 is a hole through which the absorbent core 11 passes in the thickness direction.

Specifically, the deformation of the absorbent core 11 when the diaper 1 is worn is explained. Fig. 7 is a schematic perspective view illustrating deformation of the absorbent core 11 when the diaper 1 is worn.

In the diaper 1, since the central low basis weight region 32 is penetrated by the absorbent core 11 in the thickness direction and has the lowest rigidity, the absorbent core 11 is most likely to be subjected to bending deformation in the central low basis weight region 32. Therefore, when the absorbent core 11 is sandwiched between the legs in the crotch of the wearer when the diaper 1 is worn, the absorbent core 11 is folded right and left in the vertical direction (the longitudinal direction of the absorbent core 11) at the portion of the central low basis weight region 32. As a result, in the crotch region 11B between the central low basis weight regions 32 in the longitudinal direction, the absorbent core 11 is deformed into a convex shape toward the skin of the wearer along the longitudinal direction, forming convex portions 11t, as shown in fig. 7. The absorbent core 11 is deformed to protrude toward the skin side at the crotch portion 11B, so that the convex portions 11t are easily attached along the excretory opening of the wearer and the cleft of the buttocks, and the absorption of excrement can be improved at the crotch portion. In the abdomen portion 10F, the absorbent core 11 rises along the curved surface shape of the wearer's abdomen from the crotch portion 11B to the lower abdomen portion 11A. On the other hand, in the back portion 10R, the absorbent core 11 rises along the curved surface shape of the wearer's buttocks from the crotch portion 11B to the buttocks portion 11C. As a result, the absorbent core 11 is deformed into the shape shown in fig. 7 when the diaper 1 is worn.

[ expansion/contraction ratio of diaper 1 ]

The magnitude of the ventral conformability of the diaper 1 differs in each of the ventral first region F1, the ventral second region F2, the ventral third region F3, and the ventral fourth region F4. The sizes of the followability of the back side of the diaper 1 are different in the back side first region R1, the back side second region R2, the back side third region R3, and the back side fourth region R4, respectively. Fig. 8 is a view for explaining the regions of different sizes of the followability of the diaper 1 in the unfolded and extended state. Fig. 9 is a view illustrating each welded region of the diaper 1 in an unfolded and extended state. In fig. 8 and 9, the boundaries of the respective regions are indicated by solid lines for convenience.

In the diaper 1, the magnitude of the followability of each region is caused by the elastic coefficient of the outer cover 20 and the presence or absence of the absorbent core 11. The elastic coefficient of the exterior portion 20 is a force for extending a unit area region of the exterior portion 20 by a predetermined length.

Stretchable sheets

215 and 225 are disposed over substantially the entire region on the front and back sides of the diaper 1.

In a conventional pant-type disposable diaper, since the absorbent core has high rigidity, a difference occurs in rigidity between a portion where the outer cover and the absorbent core overlap in the thickness direction (front-back direction) and a portion where the outer cover and the absorbent core do not overlap in the thickness direction. When the elastic coefficient of the outer cover portion in the portion overlapping the absorbent core is smaller than the elastic coefficient of the portion not overlapping the absorbent core, the followability in wearing is largely different in the portion where the outer cover portion and the absorbent core overlap and the portion where the outer cover portion and the absorbent core do not overlap, with the upper end of the absorbent core as a boundary, and the degree of followability to the body and the movement of the body are different, and there is a possibility that the wearer feels uncomfortable.

In this regard, the abdomen-side second region F2 is provided as a buffer region for buffering the difference in followability between the abdomen-side first region F1 and the abdomen-side third region F3 in fig. 8 on the abdomen side of the diaper 1. The abdomen-side second region F2 is a region that has smaller followability than the abdomen-side first region F1 and larger followability than the abdomen-side third region F3. Similarly, the back-side second region R2 is provided on the back side of the diaper 1 as a cushion region for cushioning a difference in the followability between the back-side first region R1 and the back-side third region R3. The back-side second region R2 is a region that is smaller in followability than the back-side first region R1 and larger in followability than the back-side third region R3. Each region will be described below.

The ratio of the area of the welded part 25 per unit area in the abdomen side and the back side of the diaper 1 contributes to the magnitude of the elastic coefficient of the outer cover 20 which expands and contracts in the right-left direction. Specifically, the greater the ratio of the area of the welded portion 25 per unit area, the lower the stretchability of the

stretchable sheets

215 and 225, and the lower the respective elastic coefficients of the abdomen-side outer cover 21 including the stretchable sheet 215 and the back-side outer cover 22 including the stretchable sheet 225. As shown in fig. 9, a welded region (low area ratio region) X, a welded region (high area ratio region) Y, and a welded region P are provided on the ventral side of the diaper 1, and a welded region (low area ratio region) X, a welded region (high area ratio region) Y, a welded region P, and a welded region Q are provided on the back side of the diaper 1. In the following description, the diaper 1 in the extended state is examined with respect to the ratio of the area of the weld 25 per unit area.

In the welding region X (the lower right diagonal portion in fig. 9), a welding portion 25a is provided at a predetermined ratio (for example, 2.22%) of the area of the welding portion 25 per unit area. The welded portion 25a is a circular welded portion 25, and a plurality of welded portions are arranged in a staggered manner. In welding region Y (the mesh portion in fig. 9), welding portion 25b is provided such that the proportion of the area of welding portion 25 per unit area is higher than the proportion (for example, 4.44%) of welding region X. That is, the elasticity coefficient of the exterior 20 of the welded region Y is smaller than the elasticity coefficient of the welded region X. The welded portions 25b are formed by arranging a plurality of substantially rectangular welded portions 25 inclined at 45 degrees or-45 degrees with respect to the left-right direction in a staggered manner.

Welding portions

25c and 25d are provided in welding region P (a sandy portion in fig. 9) and welding region Q (a diagonal portion at the lower left in fig. 9), respectively. Weld 25c is a circular weld 25, weld 25d is a rectangular weld 25, and the ratio of the area of weld 25 per unit area is 1.42% and 7.77%, respectively. The ratio of the area of the welded portion 25 per unit area of the welded region P and the welded region Q can be appropriately changed according to the elastic coefficient and the material of the exterior portion 20 of each portion.

The welded region P is a region where the leg hole elastic members 27 are arranged. The welded region Q is a region of the lower end portion of the region of the back side of the diaper 1 where the back-side exterior member 22 and the absorbent body 10 overlap in the thickness direction. The abdomen-side welded region Y of the diaper 1 is a region other than the upper end portion of the region where the abdomen-side outer cover 21 and the absorbent main body 10 overlap in the thickness direction. The welded region Y on the back side of the diaper 1 is a region other than the region of the upper end portion and the welded region Q in the region where the back-side exterior 22 and the absorbent body overlap in the thickness direction. The welded region X is substantially the entire region of the exterior member 20 except for the welded region Y, the welded region P, the welded region Q, and the region where the waist elastic member 26 is arranged. In the diaper 1, the welded portions 25 are not disposed in the regions where the waist elastic members 26 are disposed, but the welded portions 25 may be provided in the regions. When the welded portions 25 are provided in the regions where the waist elastic members 26 are arranged, the welded portions 25 are more preferably arranged so as not to cut the waist elastic members 26.

In the abdomen-side portion of the diaper 1, the first abdomen-side region F1 is a region where the welded region X does not overlap the absorbent core 11 (a lower right diagonal line portion in fig. 8), the second abdomen-side region F2 is a region where the welded region X overlaps the absorbent core 11 (a lower left diagonal line portion in fig. 8), the third abdomen-side region F3 is a region where the welded region Y overlaps the absorbent core 11 (a thin mesh portion in fig. 8), and the fourth abdomen-side region F4 is a region where the welded region Y does not overlap the absorbent core 11 (a thick mesh portion in fig. 8).

The following properties in the left-right direction of each of the ventral first region F1, the ventral second region F2, and the ventral third region F3 were compared. The abdomen-side first region F1 does not overlap the absorbent core 11 in the thickness direction, and the outer cover 20 in the welded region X has a high modulus of elasticity, and therefore has high conformability when worn. On the other hand, the abdomen-side second region F2 and the abdomen-side third region F3 overlap the absorbent core 11 in the thickness direction, and therefore the followability is lower than the abdomen-side first region F1 when worn.

Assuming that the ratios of the areas of the weld portions per unit area in the weld region X and the weld region Y are the same, the elastic coefficients of the abdomen-side exterior 21 corresponding to the abdomen-side second region F2 and the abdomen-side third region F3 are the same, and therefore, the conformability to the abdomen-side second region F2 and the abdomen-side third region F3 during wearing is approximately the same. Accordingly, the difference in the following performance when worn between the abdomen-side second region F2 and the abdomen-side third region F3 and the abdomen-side first region F1 becomes large.

Therefore, the ratio of the area of the weld 25 per unit area in the abdomen-side second region F2 is made equal to the ratio of the area of the weld 25 per unit area in the abdomen-side first region F1, and the ratio of the area of the weld 25 per unit area in the abdomen-side third region F3 is made larger than the ratio of the area of the weld 25 per unit area in the abdomen-side first region F1. Thus, the elastic modulus of the exterior 20 in the abdomen-side second region F2 of the abdomen-side exterior 21 is larger than the elastic modulus of the exterior 20 in the abdomen-side third region F3. The abdomen-side second region F2 provided with the abdomen-side exterior 21 having a larger elastic modulus has greater followability when worn than the abdomen-side third region F3. Further, by disposing the abdomen-side second region F2 between the abdomen-side first region F1 and the abdomen-side second region F2 in the vertical direction, the followability during wearing can be gradually reduced from the abdomen-side first region F1 toward the abdomen-side third region F3. That is, the abdomen-side second region F2 is a buffer region between the abdomen-side first region F1 and the abdomen-side third region F3 on the abdomen side of the diaper 1, and the difference in conformability between the abdomen-side first region F1 and the abdomen-side third region F3 when worn is gradually reduced, so that discomfort such as stickiness felt by the wearer can be easily reduced.

Similarly, with respect to the back side of the diaper 1, the back side first region R1 is a region where the welded region X does not overlap the absorbent core 11 (a right descending hatched portion in fig. 8), the back side second region R2 is a region where the welded region X overlaps the absorbent core 11 (a left lower hatched portion in fig. 8), the back side third region R3 is a region where the welded region Y overlaps the absorbent core 11 (a thin mesh portion in fig. 8), and the back side fourth region R4 is a region where the welded region Y does not overlap the absorbent core 11 (a thick mesh portion in fig. 8).

In the back side portion of the diaper 1, the ratio of the area of the weld 25 per unit area of the back-side second region R2 is set to be the same as that of the back-side first region R1, and the ratio of the area of the weld 25 per unit area of the back-side third region R3 is set to be greater than that of the back-side first region R1. Thus, the back-side second region R2 of the back-side exterior 22 has a higher elastic coefficient than the back-side third region R3, and therefore the back-side second region R2 having a higher elastic coefficient has greater followability when worn than the back-side third region R3. In addition, by disposing the back-side second region R2 between the back-side first region R1 and the back-side second region R2 in the vertical direction, the following ability during wearing can be gradually reduced from the back-side first region R1 toward the back-side third region R3. That is, the back-side second region R2 is a buffer region between the back-side first region R1 and the back-side third region R3 on the back side of the diaper 1, and the back-side second region R2 is likely to absorb a difference in followability when worn. Further, it is easy to reduce the fear of giving the wearer a sense of discomfort due to the difference in followability when the back-side first region R1 and the back-side third region R3 are worn.

In the center line C-C in the left-right direction of the diaper 1 in the extended state shown in fig. 8 and the like, the length dr2 in the up-down direction of the back-side second region R2 is preferably longer than the length df2 in the up-down direction of the abdomen-side second region F2 (df2 < dr 2). The back side of the diaper 1 is a portion that comes into contact with the buttocks and waist of the wearer, and therefore needs to be deformed into a shape corresponding to the shape of the body. However, if the difference in the following performance between the back-side first region R1 and the back-side third region R3 when worn becomes large, there is a possibility that the wearer may be easily given a sense of incongruity. In contrast, by making the length dr2 in the vertical direction of the back-side second region F2 longer, the following performance when worn tends to be gradually reduced from the back-side first region R1 toward the back-side third region R3, and the back-side second region F2 more easily buffers the difference in the following performance when worn between the back-side first region R1 and the back-side third region R3, as compared to the case where the length df2 in the vertical direction of the abdomen-side second region F2 is equal to or less than. Further, in the diaper 1, the vertical length dr3 of the back-side third region R3 is longer than the vertical length df3 of the stomach-side third region F3 on the center line in the left-right direction.

In addition, the absorbent core 11 preferably has the low basis weight regions 30 in the ventral second regions F2. Likewise, it is preferred to have low basis weight regions 30 in the backside second regions R2. As described above, the low basis weight region 30 serves as a bending start point of the absorbent core 11, and the absorbent core 11 is easily deformed. That is, the low basis weight region 30 is provided in order to form a shape that matches the body of the wearer, but the low basis weight region 30 is also effective in order to improve the fit of the absorbent core 11. As shown in fig. 8 and the like, a plurality of low basis weight regions 31 are provided in the ventral second region F2 at intervals in the left-right direction. That is, the low basis weight region 31 is a region having a lower basis weight than the surroundings, and therefore has lower rigidity than the surroundings. Therefore, by providing the low basis weight regions 31 in the abdomen-side second region F2 (back-side second region R2), the following performance when the abdomen-side second region F2 (back-side second region R2) is worn is increased, the difference in following performance when the abdomen-side third region F3 (back-side third region R3) is easily increased, the difference in following performance when the abdomen-side first region F1 is easily decreased, and the following performance when the abdomen-side third region F3 (back-side third region R3) is easily reduced more gradually from the abdomen-side first region F1 (back-side first region R1) toward the abdomen-side third region F3 (back-side third region R3).

Further, it is preferable that the absorbent core 11 has the low basis weight regions 30 in the ventral third regions F3. As shown in fig. 8 and the like, the low basis weight regions 31 are provided in plurality in the ventral third region F3 at intervals in the left-right direction. The absorbent core 11 has the low basis weight region 31 not only in the abdomen-side second region F2 but also in the abdomen-side third region F3, and thus the rigidity of the absorbent core 11 itself overlapping with the abdomen-side outer cover 21 can be further reduced. This can further reduce the difference in the following performance between the abdomen-side first region F1 and the abdomen-side third region F3 when worn, and thus can easily reduce the discomfort given to the wearer. Likewise, it is preferable that the absorbent core 11 has the low basis weight regions 31 in the back-side third regions R3.

The number of the low basis weight regions 30 in the left-right direction of the low basis weight regions 31 provided in the front-side third region F3 or the back-side third region R3 is more preferably larger at the upper end than at the lower end. Specifically, in the diaper 1 shown in fig. 8 and the like, the number of the low basis weight regions 31 provided at the upper end portion of the third abdominal region F3 is 6, the number of the low basis weight regions 31 provided at the lower end portion is 2, and the number of the low basis weight regions 32 is 1, which is 3 in total. The number of the low basis weight regions 31 provided at the upper end portion of the back-side third region R3 is 6, and the number of the low basis weight regions 30 provided at the lower end portion is 5. Thus, the upper end of the abdomen-side third region F3 closer to the abdomen-side second region F2 can have greater conformability than the lower end of the abdomen-side third region F3. That is, since the followability during wearing can be gradually reduced from the upper end portion to the lower end portion in the abdomen-side third region F3, the difference in followability during wearing between the abdomen-side second region F2 and the abdomen-side third region F3 can be reduced, and the followability during wearing can be easily gradually reduced from the abdomen-side first region F1 toward the abdomen-side third region F3. This reduces the discomfort felt by the wearer due to the difference in the conformability between the abdominal-side first region F1 and the abdominal-side third region F3 when worn. The number of the low basis weight regions 30 in the back-side third region R3 is also preferably greater at the upper end than at the lower end, as is the number of the low basis weight regions 30 in the front-side third region F3.

Since the abdomen-side fourth region F4 is a region where the welded region Y does not overlap the absorbent core 11, the contraction force in the left-right direction of the abdomen-side fourth region F4 is larger than the contraction force in the left-right direction of the abdomen-side third region F3, which is a region where the welded region Y overlaps the absorbent core 11. Since the abdomen-side fourth region F4 is the welded region Y and overlaps the absorbent main body 10, the dressing-time followability of the abdomen-side fourth region F4 is smaller than the dressing-time followability of the abdomen-side first region F1. In the front side of the diaper 1, the front side fourth region F4 is adjacent to the front side third region F3 from the outside of the front side third region F3 in the left-right direction, and the front side first region F1 is adjacent to the front side fourth region F4 from the outside of the front side fourth region F4 in the left-right direction, with respect to the region overlapping the front side third region F3 in the left-right direction. Accordingly, the region overlapping with the abdomen-side third region F3 in the left-right direction has a smaller contractile force than the abdomen-side first region F1, gradually decreases in the left-right direction from the abdomen-side first region F1 toward the abdomen-side third region F3, and the abdomen-side fourth region F4 having a greater followability during wearing than the abdomen-side third region F3 is easily cushioned, so that discomfort given to the wearer due to a difference in followability during wearing between the abdomen-side first region F1 and the abdomen-side third region F3 can be reduced.

Similarly, since the back-side fourth region R4 is a region where the welded region Y does not overlap the absorbent core 11, the back-side fourth region R4 has greater conformability to wear than the back-side third region R3, which is a region where the welded region Y overlaps the absorbent core 11. Since the back-side fourth region R4 is the welded region Y and overlaps the absorbent main body 10, the contraction force in the left-right direction of the back-side fourth region R4 is smaller than the followability of the back-side first region R1 when worn. In the back side portion 10R, as for the region overlapping the back-side third region R3 in the left-right direction, the back-side fourth region R4 is adjacent to the back-side third region R3 from the outside of the back-side third region R3 in the left-right direction, and the back-side first region R1 is adjacent to the back-side fourth region R4 from the outside of the back-side fourth region R4 in the left-right direction. Thus, the region overlapping the back-side third region R3 in the left-right direction has a smaller followability than the back-side first region R1, gradually decreases in the left-right direction from the back-side first region R1 toward the back-side third region R3, and the back-side fourth region R4 having a greater followability than the back-side third region R3 is more likely to absorb shock, so that discomfort to the wearer due to a difference in followability when worn between the back-side first region R1 and the back-side third region R3 can be reduced.

While the embodiments of the present invention have been described above, the above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. It is needless to say that the present invention can be modified or improved without departing from the gist thereof, and equivalents thereof are included in the present invention.

In the above embodiment, the first region (F1, R1), the second region (F2, R2), and the third region (F3, R3) are provided in the abdominal portion 10F and the back portion 10R, respectively, but the present invention is not limited thereto. Each region may be provided on either the ventral portion 10F or the dorsal portion 10R. The stress may be appropriately determined according to the magnitude of the elastic modulus acting on the exterior 20(21, 22) and the

stretchable sheets

215, 225 of the absorbent core 11.

In the above-described embodiment, the welded part 25 has a circular shape (25a, 25d) or a rectangular shape (25b, 25c), but the present invention is not limited thereto. The shape of each welded portion 25 may be any shape such as an ellipse or a polygon. Further, the welding portion 25 having a different shape may be provided in the same region.

Description of reference numerals

1-pants-type disposable diaper (diaper, pants-type absorbent article), 1A waist opening, 1B leg opening, 10 absorbent body, 10F abdomen side portion, 10R back side portion, 11 absorbent core, 11A abdomen portion, 11B crotch portion, 11C hip portion, 11C neckdown portion, 11t convex portion, 12 top sheet, 13 back sheet, 14 side sheet, 20 exterior portion, 21 abdomen side exterior portion (waist portion, abdomen side waist portion), 21s front side stretchable region, 213 skin side sheet (non-stretchable sheet), 214 non-skin side sheet (non-stretchable sheet), 215 stretchable sheet, 22 back side exterior portion (waist portion, back side exterior portion), 22s back side stretchable region, 223 skin side sheet (non-stretchable sheet), 224 non-skin side sheet (non-stretchable sheet), 225 stretchable sheet, 23 crotch exterior portion, 23s crotch stretchable region, 231 side sheet, 232 non-skin side sheet, A 233 stretchable sheet, a 24 end joining region, a 25 welded portion, 25a, 25b, 25c, 25d welded portions, 26 waist elastic members, 27 leg elastic members, 28 crotch elastic members, 30 low basis weight regions, 31h upper and lower low basis weight regions, 31s left and right low basis weight regions, 32 center low basis weight region, 40 leakage barrier portions, 41 leakage barrier elastic members, 42 leakage barrier elastic members, a CL predetermined position, a F1 ventral first region, a F2 ventral second region, a F3 ventral third region, a R1 dorsal first region, a R2 dorsal second region, a R3 dorsal third region, a P welded region, a Q welded region, an X welded region (low area ratio region), and a Y welded region (high area ratio region).

Claims

1. A pant-type absorbent article having a vertical direction, a horizontal direction, and a front-back direction intersecting each other, comprising:

a pair of waist portions; and

an absorbent body having an absorbent core disposed along the vertical direction and bent in the longitudinal direction at a lower end portion of the vertical direction,

it is characterized in that the preparation method is characterized in that,

at least one of the pair of waist units is provided with a non-stretchable sheet and a stretchable sheet stretchable in the left-right direction,

the non-stretchable sheet and the stretchable sheet are welded to each other in the front-rear direction by a plurality of welding portions,

in the state of being extended, the elastic element is in a non-elastic state,

a low area ratio region having a ratio of an area of the weld portion per unit area of a predetermined value and a high area ratio region having a ratio of an area of the weld portion per unit area of greater than that of the low area ratio region,

in the one waist portion, when a region where the low area ratio region does not overlap with the absorbent core is a first region, a region where the low area ratio region overlaps with the absorbent core is a second region, and a region where the high area ratio region overlaps with the absorbent core is a third region,

in the central portion in the left-right direction,

the second region is disposed between the first region and the third region in the up-down direction.

2. The pant-type absorbent article according to claim 1,

the absorbent core has a low basis weight region in the second region having a lower average basis weight than the surrounding.

3. The pant-type absorbent article according to claim 2,

the absorbent core also has a low basis weight region in the third region having a lower average basis weight than the surroundings.

4. The pant-type absorbent article according to claim 3,

a plurality of low basis weight regions provided in the third region are provided at intervals in the left-right direction,

the number of the low basis weight regions provided at the upper end portion of the third region is larger than the number of the low basis weight regions provided at the lower end portion of the third region in the left-right direction.

5. The pant-type absorbent article according to any one of claims 2 to 4,

the low basis weight regions have upper and lower low basis weight regions having a first length in the up-down direction and left and right low basis weight regions having a second length in the left-right direction.

6. The pant-type absorbent article according to any one of claims 1 to 5,

regarding the region overlapping with the third region in the left-right direction,

a fourth region where the high area ratio region and the absorbent core do not overlap is adjacent to the third region from the outside of the third region in the left-right direction,

the first region is adjacent to the first region from the outside of the fourth region in the left-right direction.

7. The pant-type absorbent article according to any one of claims 1 to 6,

the pair of waist portions each have the welded portion, the first region, the second region, and the third region,

at the center in the left-right direction and in the extended state,

the length in the up-down direction of the second region of the back-side waistline portion is longer than the length in the up-down direction of the second region of the abdomen-side waistline portion.