JP7350518B2 - Pants-type absorbent article - Google Patents

Description

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

Pants-type disposable diapers are known as pants-type absorbent articles. For example, Patent Document 1 discloses a pants-shaped diaper 10 having an absorbent main body 20 including an exterior portion 30, a waist elastic member 33, and an absorbent core 22. The absorbent main body 20 (absorbent core 22) is joined to the exterior body 30 so as to extend from the ventral side part A to the dorsal side part B so as to match the longitudinal direction of the diaper 10.

Japanese Patent Application Publication No. 2013-255558

In the diaper 10 of Patent Document 1, the force of the waist elastic member 33 to expand and contract in the width direction is reduced by overlapping and joining the exterior portion 30 and the absorbent core 22. Therefore, there is a difference in rigidity between the area where the absorbent cores 22 are overlapped and the area where the absorbent cores 22 are not overlapped, and the elasticity of the exterior part 30 between the area where the absorbent cores 22 are overlapped and the area where they are not overlapped. Since there are also differences in coefficients, when worn, the shape of the body and the ability to follow body movements differ across the upper end of the absorbent core 22, which may give the wearer a sense of discomfort.

The present invention has been made in view of the above-mentioned problems, and its purpose is to prevent the waist region and the absorbent core from overlapping in the region where the waist region and the absorbent core overlap. It is an object of the present invention to provide a pants-type absorbent article that reduces the sense of discomfort given to a wearer due to the difference in followability between the absorbent article and the worn region.

The main invention for achieving the above purpose is:
It has a vertical direction, a horizontal direction, and a front-back direction that intersect with each other,
an absorbent main body including an absorbent core arranged along the vertical direction and bent in the front-back direction at a lower end in the vertical direction;
an exterior part including a pair of waist circumference parts and located on the non-skin side of the absorbent main body;
A pants-type absorbent article having
In the lower end portion, the side edges in the left and right direction of the absorbent main body are located outside the side edges in the left and right direction of the exterior part,
In at least one of the pair of waist portions,
comprising a non-stretchable sheet and a stretchable sheet that stretches in the left-right direction,
The non-stretchable sheet and the stretchable sheet are welded in the front-rear direction by a plurality of welded parts,
In the extended state,
having a low area ratio region in which the area ratio of the welded part per unit area is a predetermined value, and a high area ratio area in which the area ratio of the welded part per unit area is larger than the low area ratio region,
Of the one girth part,
An area that does not overlap with the absorbent core in the low area ratio area is defined as a first area,
A region where the low area ratio region and the absorbent core overlap is a second region,
If the region where the high area ratio region and the absorbent core overlap is defined as a third region,
In the center part in the left-right direction,
The second region is provided between the first region and the third region in the vertical direction ,
If the area where the high area ratio area and the absorbent core do not overlap is defined as a fourth area,
The fourth region is adjacent to the third region from the outside of the third region in the left-right direction,
The first region is a pants-type absorbent article characterized in that the first region is adjacent to the fourth region from the outside of the fourth region in the left-right direction .
Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

According to the present invention, the second region provided between the first region and the third region, which have a large difference in followability when worn, reduces the difference in followability between the first region and the third region when worn. It becomes easier to cushion the wearer, and it is possible to reduce the possibility that the wearer may feel uncomfortable due to the difference in followability between the first region and the third region when worn.

1 is a perspective view of a pants-type disposable diaper 1. FIG. FIG. 2 is a schematic plan view of the diaper 1 in an expanded and stretched state, viewed from the skin side. 3 is a schematic cross-sectional view taken along line II in FIG. 2. FIG. FIG. 4A is a schematic plan view of the absorbent main body 10 in an expanded and stretched state, viewed from the skin side. FIG. 4B is a sectional view taken along line AA in FIG. 4A. 1 is a schematic plan view of the diaper 1 in an expanded and stretched state, and is a diagram illustrating the positional relationship between various elastic regions and an absorbent core 11. FIG. FIG. 2 is a plan view of the absorbent core 11 viewed from the skin side. FIG. 3 is a schematic perspective view illustrating deformation of the absorbent core 11 when the diaper 1 is worn. FIG. 3 is a diagram illustrating regions in which the followability of the diaper 1 in the unfolded and stretched state differs. FIG. 3 is a diagram illustrating each welding area of the diaper 1 in an expanded and stretched state.

From the description of this specification and the attached drawings, at least the following matters will become clear.
It has a vertical direction, a horizontal direction, and a front-back direction that intersect with each other, and includes a pair of girth parts and an absorbent core arranged along the vertical direction, and is bent in the front-back direction at the lower end of the vertical direction. a pants-type absorbent article, comprising: a non-stretchable sheet; and a stretchable sheet that stretches in the left-right direction in at least one of the pair of waist regions; The non-stretchable sheet and the stretchable sheet are welded in the front-rear direction by a plurality of welded parts, and in the stretched state, the area ratio of the welded parts per unit area is a low area ratio of a predetermined value. and a high area ratio area in which the ratio of the area of the welded portion per unit area is larger than the low area ratio area, and of the one waistline part, the low area ratio area and the absorbent core are A non-overlapping region is defined as a first region, a region where the low area ratio region and the absorbent core overlap is defined as a second region, and a region where the high area ratio region and the absorbent core overlap is defined as a third region, Pants-type absorbent article, characterized in that the second region is provided in the center part in the left-right direction between the first region and the third region in the vertical direction. It is a type absorbent article.

According to such a pants-type absorbent article, the second region provided between the first region and the third region, which has a large difference in conformability when worn, has a large difference in followability when the first region and the third region are worn. This makes it easier to buffer the difference in followability between the first region and the third region, and reduces the possibility that the wearer will feel uncomfortable due to the difference in followability between the first region and the third region when worn.

In such a pants-type absorbent article, it is preferable that the absorbent core has a low basis weight region in the second region where the average basis weight is lower than the surrounding area.

According to such a pants-type absorbent article, the rigidity of the second region can be reduced by the low basis weight region provided in the second region. The first region can be made larger than the first region, and the difference in followability between the first region and the third region when worn can be easily buffered.

In such a pants-type absorbent article, it is preferable that the absorbent core has a low basis weight area in the third area as well, where the average basis weight is lower than the surrounding area.

According to such a pants-type absorbent article, the low basis weight regions provided in the second region and the third region can reduce the overall rigidity of one of the waist portions of the absorbent core. , it is possible to further reduce the difference in followability between the first region and the third region when worn.

In this pants-type absorbent article, a plurality of low basis weight regions provided in the third region are provided at intervals in the left-right direction, and in the left-right direction, an upper end of the third region It is desirable that the number of the low basis weight regions provided at the lower end of the third region is greater than the number of the low basis weight regions provided at the lower end of the third region.

According to such a pants-type absorbent article, by making the rigidity of the upper end portion of the third region closer to the second region lower than the rigidity of the lower end portion, the stiffness of the upper end portion of the third region from the second region to the lower end portion of the third region is lowered. This makes it easier to reduce the followability in stages, and it becomes easier to reduce the discomfort caused to the wearer due to the difference in followability when worn.

In such a pants-type absorbent article, the low basis weight regions include 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. It is desirable to have

According to such a pants-type absorbent article, the upper and lower low basis weight regions and the left and right low basis weight regions tend to become bending points, making it easy for the absorbent core to deform in the vertical and horizontal directions, causing damage to the wearer's body and It becomes easier to shape according to movement.

In such a pants-type absorbent article, in a region adjacent to the third region from the left and right direction , a fourth region that is a region that does not overlap with the absorbent core in the high area ratio region is the third region. It is desirable that the first region adjoins the third region from the outside of the region in the left-right direction, and the first region adjoins the fourth region from the outside of the fourth region in the left-right direction.

According to such a pants-type absorbent article, in a region that overlaps with the third region in the left-right direction, the fourth region can easily buffer the difference in followability between the first region and the third region when worn. Therefore, it is possible to reduce the possibility that the wearer may feel uncomfortable due to the difference in stress in the left and right direction caused by the difference in followability between the first region and the third region when worn.

In such a pants-type absorbent article, each of the pair of waist portions has the welded portion, the first region, the second region, and the third region, and is located at the center in the left-right direction, and In the extended state, it is desirable that the length of the second region of the dorsal waistline portion in the vertical direction is longer than the length of the second region of the ventral waistline portion in the vertical direction.

According to such a pants-type absorbent article, on the back side, stress caused by the difference in followability when the first region and the third region are worn tends to concentrate on the unevenness of the buttocks and waist, so By providing a wide second region that buffers the difference in followability between the first region and the third region, it is possible to reduce the stress caused by the difference in circumferential force between the first region and the third region.

===Embodiment===
EMBODIMENT OF THE INVENTION Hereinafter, an embodiment will be described using a pants-type disposable diaper 1 for adults (hereinafter also referred to as "diaper 1") as an example of the "pants-type absorbent article" of the present invention. However, the pants-type absorbent article of the present invention can also be used as, for example, disposable diapers for children, sanitary products (shorts-type napkins), and the like.

<<Overall configuration 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, viewed from the skin side. FIG. 3 is a schematic cross-sectional view taken along line II in FIG. 2. FIG. 4A is a schematic plan view of the absorbent main body 10 in an expanded and stretched state, viewed from the skin side. CC in FIG. 2 and the like indicates the center in the left-right direction. FIG. 4B is a sectional view taken along line AA in FIG. 4A. Note that in FIG. 4B, for the sake of simplification of explanation, a low basis weight region 30 (described later) provided in the absorbent core 11 is not shown. In addition, the "stretched state" of the diaper 1 is a state in which the diaper 1 is stretched without wrinkles, and the dimensions of each member constituting the diaper 1 (for example, the exterior part 20, etc. described later) match the dimensions of that member alone. Or, it is in a state where it has been expanded until it reaches a length close to that length. “Natural state” is defined as follows. First, after taking out the diaper 1 packaged as a product from the package, pull the left and right ends of the diaper 1 outward in the left and right direction until the length matches or is close to the dimensions of each component alone. Stretch it. After continuing this stretched state for 15 seconds, the diaper 1 is released from the stretched state and placed on a flat surface such as a desk. The diaper 1 is in its natural state after being placed on this flat surface for 5 minutes. In FIGS. 4 to 9, the absorbent core 11, the low basis weight region 30, etc. are not visible from the outside, but are shown by solid lines for convenience.

The diaper 1 has an up-down direction, a left-right direction, and a front-back direction that intersect with each other, and has a thickness direction in which each member is laminated, as shown in FIG. In the vertical direction, the side that is the wearer's torso side is the upper side, and the side that is the wearer's crotch side is the lower side. In the front-back direction, the side that is on the ventral side of the wearer is the front side, and the side that is on the back side of the wearer is the back side. In the thickness direction, the side in contact with the wearer's body is the skin side, and the opposite side is the non-skin side. Moreover, in the unfolded state of FIG. 2, the diaper 1 has a longitudinal direction and a width direction that intersect with each other. The longitudinal direction is a direction along the up-down direction, and the width direction is the same direction as the left-right direction.

The diaper 1 includes an absorbent body 10 having a rectangular shape in plan view, and an exterior portion 20 located on the non-skin side of the absorbent body 10. The exterior part 20 includes a ventral exterior part (also referred to as "ventral girth part") 21 located on the front side in the anteroposterior direction in FIG. ) 22, and an inseam exterior part 23 that connects them. The members adjacent to each other in the thickness direction are joined with adhesive or the like.

A ventral exterior part 21 is located at one end of the absorbent body 10 in the longitudinal direction, and a back exterior part 22 is located at the other end of the absorbent body 10 in the longitudinal direction. In the longitudinal direction of the absorbent main body 10, the side where the ventral exterior part 21 is located is the front side, and the side where the back exterior part 22 is located is the rear side. That is, the ventral exterior part 21 is located at the front upper end of the absorbent main body 10, and the back exterior part 22 is located at the rear upper end of the absorbent main body 10. Further, the crotch member 23 is located closer to the skin than the ventral exterior part 21 and the dorsal exterior part 22.

In addition, in the diaper 1 of this embodiment, the exterior part 20 is comprised from three members, but it is not limited to this. For example, the ventral exterior portion 21, the dorsal exterior portion 22, and the crotch portion 23 may be one member. Alternatively, a configuration without the crotch portion 23 or a configuration in which a member different from the exterior portion 20 is further laminated on the non-skin side of the exterior portion 20 may be used.

In the unfolded diaper 1 shown in FIG. 2, the absorbent main body 10 is folded in two at a predetermined position CL in the longitudinal direction, and both sides of the ventral exterior part 21 in the left and right direction and both sides of the back exterior part 22 in the left and right direction are folded in half. By joining them by welding or the like, the pants shape shown in FIG. 1 is obtained. That is, the longitudinal direction of the absorbent main body 10 is along the up-down direction of the diaper 1, and the ventral exterior part 21 and the dorsal exterior part 22 are connected in an annular manner to form the waist opening 1a and the pair of leg openings 1b. . Hereinafter, the area where the ventral exterior part 21 and the dorsal exterior part 22 are joined will be referred to as an end joining area 24.

In addition, in this specification, of the absorbent main body 10 (absorbent core 11) that is bent at a predetermined position CL, the portion that is bent toward the front side is referred to as the “ventral portion 10F”, and the portion that is bent toward the rear side is referred to as “ventral portion 10F”. is referred to as "dorsal part 10R". That is, in the longitudinal direction of FIG. 2, the area in front of the predetermined position CL of the absorbent main body 10 (absorbent core 11) is called the "ventral part 10F", and the area behind the predetermined position CL is called the "dorsal part 10F". It may be called "side part 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 backsheet 13 has a two-layer structure including a liquid-impermeable sheet 13a and a hydrophobic sheet 13b disposed on the non-skin side. As the liquid-impermeable sheet 13a, for example, a resin film is used, and as the hydrophobic sheet 13b, for example, a flexible hydrophobic nonwoven fabric or the like is used. Note that the back sheet 13 may have a single layer structure of a liquid-impermeable sheet 13a.

Side seats 14 are provided on both sides of the back seat 13 in the left-right direction. This side sheet 14 extends outward in the left-right direction from both ends 11es and 11es in the left-right direction of the absorbent core 11, and is located inside and thickly in the left-right direction with both ends 10es and 10es in the left-right direction of the absorbent body 10 being folded back positions. A pair of leak-proof wall portions 40 are formed by being folded back toward the skin side in the longitudinal direction. Leak-proof wall elastic members 41 and 42, such as thread rubber, are fixed to the leak-proof wall portion 40 in a stretched state along the longitudinal direction (vertical direction) of the absorbent main body 10. By contracting the leak-proof wall elastic members 41 and 42 in the longitudinal direction, the pair of leak-proof walls 40 rises toward the skin at both ends of the absorbent main body 10 in the left-right direction, and the leak-proof walls (legs) of the diaper 1 rise. function as side gathers). Note that the leak-proof wall portion 40 may be formed by not providing the side sheet 14 and extending the back sheet 13 (liquid permeable sheet 13b) to the outside of the absorbent core 11 in the left-right direction. .

As shown in FIG. 3, the ventral exterior part 21 and the dorsal exterior part 22 each include skin-side sheets 213, 223 located on the skin side, and non-skin-side sheets 214, 224 located on the non-skin side. , and elastic sheets 215 and 225 located between them and having elasticity at least in the left-right direction of the diaper 1.

The skin-side sheets 213, 223 and the non-skin-side sheets 214, 224 are preferably flexible sheets, and for example, spunbond nonwoven fabric, SMS nonwoven fabric, or the like is used. The skin-side sheets 213, 223 and the non-skin-side sheets 214, 224 are non-stretchable sheets having lower stretchability than the stretchable sheets 215, 225.

The stretchable sheets 215 and 225 include, for example, a polyurethane elastomer which is an elastic thermoplastic elastomer fiber, and polypropylene (PP) which is a polyolefin resin which is an inelastic thermoplastic resin fiber. It is a stretchable nonwoven fabric that has been subjected to an appropriate stretching process such as gear stretching. As a result of this stretching process, the stretchable sheets 215 and 225 have elasticity in a predetermined direction. Note that the stretching process may be performed in directions perpendicular to each other, or may be performed only in a predetermined direction. If stretching is performed only in a predetermined direction, stretchability will occur in the predetermined direction, but since not all fibers are oriented along the predetermined direction, stretchability will also occur in the direction orthogonal to the predetermined direction. is expressed.

The skin-side sheets 213, 223, the non-skin-side sheets 214, 224, and the stretchable sheets 215, 225 are joined by a plurality of welded parts 25 (FIG. 9) scattered about. The welded portion 25 is, for example, a region subjected to welding treatment such as ultrasonic welding or thermal welding. Since the sheets are joined by welds, the sheets are softer to the touch than, for example, when they are joined using a hardening adhesive. Furthermore, when the stretchable sheets 215, 225 contract between the welded parts 25, the skin-side sheets 213, 223 and the non-skin-side sheets 214, 224 swell between the welded parts 25, causing wrinkles. This makes it softer to the touch and gives the user a visually softer impression. Details of the welded portion 25 will be described later.

With such a configuration, the ventral exterior part 21 and the dorsal exterior part 22 have elasticity in the left-right direction (and up-down direction) of the diaper 1 as a whole. FIG. 5 is a schematic plan view of the diaper 1 in an expanded and stretched state, and is a diagram illustrating the positional relationship between various elastic regions and the absorbent core 11. As shown in FIG. 5, the region in the ventral exterior portion 21 that exhibits elasticity in the left-right direction is the front stretchable region 21s, and the region in the dorsal exterior portion 22 that exhibits stretchability in the left-right direction is the rear region. This is the side elastic region 22s (shaded area in FIG. 5).

Note that a stretchable film may be used as the stretchable sheets 215 and 225 instead of a stretchable nonwoven fabric. However, since the elastic film has a substantially uniform thickness, the bulges of the skin-side sheets 213, 223 and the non-skin-side sheets 214, 224 between the welded portions 25a, 25b are likely to collapse. On the other hand, since the elastic sheets 215, 225 made of elastic non-woven fabric increase in thickness between the welded parts 25a, 25b, the bulges of the skin-side sheets 213, 223 and the non-skin-side sheets 214, 224 are difficult to collapse, and the texture is smooth. The softness and aesthetics can be maintained.

In addition, in the ventral side exterior part 21 and the dorsal side exterior part 22, a plurality of waist elastic members 26 such as thread rubber are arranged in the region along the waist opening 1a. Similarly, a plurality of leg elastic members 27 such as thread rubber are arranged in the region along the leg opening 1b. In other words, the waist and legs of the diaper 1 are firmly attached to the wearer's body by the waist elastic members 26 and leg elastics 27, thereby preventing the diaper 1 from slipping off or leaking from the legs. On the other hand, the elastic sheets 215 and 225 gently fit the entire surface of the other parts to the wearer's body, reducing the feeling of tightness.

The crotch member 23 has a substantially hourglass shape in plan view, which is curved inward in the left-right direction at the central portion in the longitudinal direction. Further, 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 is located between them in the vertical direction of the diaper 1. It has an elastic sheet 233 that imparts elasticity in the longitudinal direction of the absorbent main body 10. These sheets 231 to 233 are joined by a plurality of welds (not shown). In the crotch member 23, a region exhibiting stretchability along the vertical direction is defined as a crotch stretchable region 23s (see the shaded area in FIG. 5).

By providing the crotch elastic region 23s, the absorbent core 11 can be brought into close contact with the wearer's crotch area, and even if the weight of the absorbent core 11 increases due to excretion, the diaper 1 can be prevented from sagging. Further, a plurality of crotch elastic members 28 are disposed in a region of the crotch member 23 along the leg opening 1b, so that the crotch member 23 comes into close contact with the wearer's leg.

As shown in FIG. 3, the absorbent main body 10 includes an absorbent core 11, a top sheet 12 located on the skin side of the absorbent core 11, and a back sheet 13 located on the non-skin side of the absorbent core 11. have.

The absorbent core 11 is a member that absorbs and retains excretory liquid such as urine, and is formed of liquid-absorbing fibers such as pulp fibers mixed with superabsorbent polymer (SAP), for example. The absorbent core 11 of this embodiment has a constriction part 11c between the front end and the rear end in the longitudinal direction, and the width in the left-right direction is narrower, as seen in a plan view as shown in FIG. 4A. It has a roughly hourglass shape. Furthermore, a low basis weight region 30 is formed in the absorbent core 11, which is a region having a lower basis weight than the surrounding area. Further, the outer peripheral surface of the absorbent core 11 may be covered with a liquid-permeable sheet such as tissue paper or nonwoven fabric.

The low basis weight regions 30 (31, 32) can make it easier for the absorbent core 11 (absorbent main body 10) to deform 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, when worn, the absorbent core 11 is placed in a "lower abdominal region 11A" located in the lower abdomen of the wearer, an "inseam region 11B" located in the lower crotch of the wearer, and a "crotch region 11B" located in the wearer's buttocks. It has a "buttock region 11C" located therein. In FIG. 6, the region that overlaps with the ventral exterior portion 21 is the lower abdominal region 11A, the region that overlaps with the dorsal exterior portion 22 is the buttock region 11C, and the area between them is the crotch region 11B. That is, the lower abdominal region 11A is a region located on the ventral side portion 10F of the diaper 1, and the buttock region 11C is a region located on the dorsal side portion 10R of the diaper 1. The crotch region 11B is located at the lower end of the pants-shaped diaper 1 in the vertical direction, and is a region provided across the predetermined position CL and between the ventral part 10F and the dorsal part 10R.

A plurality of low basis weight regions 31 are provided at intervals in the left-right direction at each of the lower abdominal region 11A, the crotch region 11B, and the buttocks region 11C. Further, the low basis weight region 31 includes a vertical low basis weight region 31h having a predetermined length (first length) dh in the vertical direction and a predetermined length in the left and right direction along the left and right direction. It has left and right low basis weight regions 31s having a length (second length) ds. Note that 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 can be set arbitrarily, and they do not need to be the same length, and may be different lengths. good. Further, one low basis weight region 31 does not necessarily need 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 of them. Furthermore, a low basis weight region 31 having an inclined shape such as that provided in the lower abdominal region 11A may be provided.

The "basis weight" of the absorbent core 11 is the mass (g/m ² ) of the absorbent core 11 (for example, liquid absorbent fiber mixed with SAP) per unit area. Comparison of the basis weights of the absorbent core 11 between the low basis weight region 30 and the surrounding area may be performed using a well-known method. For example, there is a method of visual comparison. In addition, there is a method in which a target region is cut out as a sample from the absorbent core 11, the mass and area of each sample are measured, and the mass per unit area is calculated and compared.

The absorbent core 11 tends to bend starting from the low basis weight area 30 due to the difference in rigidity between the low basis weight area 30 and its surroundings. Therefore, when the diaper 1 is worn, the absorbent core 11 bends starting from the low basis weight region 31, thereby easily deforming to match the unevenness of the wearer's body, and easily fitting the wearer's body. That is, it becomes easier to bend up and down along the upper and lower low basis weight regions 31h, and it becomes easier to bend up and down along the left and right low basis weight regions 31s.

In addition, as shown in FIG. 6, the absorbent core 11 is located above the lower end of the diaper 1 in the vertical direction (see FIG. 1) and on the front side in the front-rear direction (abdominal part 10F) compared to the surrounding area. The core 11 has a central low basis weight region 32 which is a region where the basis weight is low. The central low basis weight region 32 is disposed along the vertical direction (longitudinal direction) in the center portion of the absorbent core 11 in the left and right direction, and the basis weight of the absorbent core 11 is lower than that of the surrounding area. It is a substantially rectangular area that is longer in the vertical direction than in the vertical direction. Similarly, a central low basis weight region 32 is also provided above the lower end of the diaper 1 in the up-down direction and on the rear side (back side portion 10R) in the front-back direction. In this embodiment, it is assumed that the absorbent core 11 does not exist 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 penetrates in the thickness direction.

Deformation of the absorbent core 11 when the diaper 1 is worn will be specifically 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, the absorbent core 11 penetrates through the central low basis weight region 32 in the thickness direction and has the lowest rigidity, so the absorbent core 11 is most likely to bend and deform in the central low basis weight region 32. Therefore, when the diaper 1 is worn, if the absorbent core 11 is pinched between the wearer's legs in the crotch region, the absorbent core 11 will move vertically (in the longitudinal direction of the absorbent core 11) in the central low basis weight region 32. Bend left and right along. As a result, in the crotch region 11B between the central low basis weight regions 32 in the longitudinal direction, the absorbent core 11 deforms into a convex shape toward the wearer's skin along the longitudinal direction, as shown in FIG. 11t is formed. By convexly deforming the absorbent core 11 toward the skin side at the crotch region 11B, the convex portion 11t easily fits along the wearer's excretory opening and buttocks crevice, improving the absorbency of excrement in the crotch region. I can do it. In the abdominal part 10F, the absorbent core 11 rises along the curved shape of the wearer's abdomen from the crotch region 11B to the lower abdomen region 11A. On the other hand, in the back side portion 10R, the absorbent core 11 rises along the curved shape of the wearer's buttocks from the crotch region 11B to the buttock region 11C. As a result, when the diaper 1 is worn, the absorbent core 11 deforms into a shape as shown in FIG. 7 .

<<About the expansion/contraction rate of diaper 1>>
The magnitude of followability on the ventral side of the diaper 1 is different in the first ventral region F1, the second ventral region F2, the third ventral region F3, and the fourth ventral region F4. Moreover, the magnitude of followability on the back side of the diaper 1 is different between the first back region R1, the second back region R2, the third back region R3, and the fourth back region R4. FIG. 8 is a diagram illustrating regions in which the followability of the diaper 1 in the unfolded and stretched state differs. FIG. 9 is a diagram illustrating each welding area of the diaper 1 in the unfolded and stretched state. In FIGS. 8 and 9, the boundaries of each area are shown by solid lines for convenience.

In the diaper 1, the degree of followability in each region depends on the elastic modulus of the exterior portion 20 and the presence or absence of the absorbent core 11. The elastic modulus of the exterior portion 20 refers to a force for expanding a unit area of the exterior portion 20 by a predetermined length. Stretchable sheets 215 and 225 are arranged on the ventral side and back side of the diaper 1, respectively, over substantially the entire area.

In conventional pants-type disposable diapers, the absorbent core has high rigidity, so the outer part and the absorbent core overlap in the thickness direction (front-to-back direction), and the outer part and the absorbent core overlap in the thickness direction. There will be a difference in rigidity between the parts that are not covered. If the elastic modulus of the exterior portion of the portion that overlaps with the absorbent core is smaller than the elastic modulus of the portion that does not overlap with the absorbent core, the followability when worn is There is a big difference between the part where the outer part and the absorbent core overlap and the part where the outer part and the absorbent core do not overlap, and the degree to which the product follows the shape of the body and body movements is different. , there was a risk that the wearer would feel uncomfortable.

In this regard, on the ventral side of the diaper 1, a second ventral region F2 is provided as a buffer region for buffering the difference in followability between the first ventral region F1 and the third ventral region F3 in FIG. The second ventral region F2 has a lower followability than the first ventral region F1, and a greater followability than the third ventral region F3. Similarly, on the back side of the diaper 1, a second back region R2 is provided as a buffer region for buffering the difference in followability between the first back region R1 and the third back region R3. The second dorsal region R2 has a lower followability than the first dorsal region R1, and a greater followability than the third dorsal region R3. Each area will be explained below.

The ratio of the area of the welded portion 25 per unit area on the ventral side and the dorsal side of the diaper 1, respectively, contributes to the magnitude of the elastic modulus of the exterior portion 20 that expands and contracts in the left-right direction. Specifically, the larger the ratio of the area of the welded portion 25 per unit area, the lower the elasticity of the elastic sheets 215 and 225, and the lower the elasticity of the elastic sheets 215 and 225 is. Each elastic modulus of the back side exterior portion 22 having the above-described structure becomes smaller. As shown in FIG. 9, the ventral side of the diaper 1 is provided with a welded area (low area ratio area) X, welded area (high area ratio area) Y, and welded area P, and the back side of the diaper 1 is provided with A welding area (low area ratio area) X, a welding area (high area ratio area) Y, a welding area P, and a welding area Q are provided. In addition, in the following description, the ratio of the area of the welded part 25 per unit area shall be considered with respect to the diaper 1 in a stretched state.

Welded portions 25a are provided in welded region X (the diagonally shaded portion downward to the right in FIG. 9) so that the ratio of the area of welded portions 25 per unit area is a predetermined ratio (for example, 2.22%). The welded parts 25a are circular welded parts 25, and a plurality of welded parts 25a are arranged in a staggered manner. Welded areas 25b are provided in welded area Y (shaded area in FIG. 9) in which the area ratio of welded areas 25 per unit area is higher than that of welded area X (for example, 4.44%). . That is, the elastic modulus of the exterior portion 20 in the welded region Y is smaller than the elastic modulus of the welded region X. In the welded portion 25b, a plurality of substantially rectangular welded portions 25 tilted at 45 degrees or -45 degrees with respect to the left-right direction are arranged in a staggered manner. The welding area P (the sandy area in FIG. 9) and the welding area Q (the diagonally shaded area downward to the left in FIG. 9) are provided with a welding part 25c and a welding part 25d, respectively. The welded portion 25c is a circular welded portion 25, and the welded portion 25d is a rectangular welded portion 25, and the area ratios of the welded portion 25 per unit area are 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 changed as appropriate depending on the elastic modulus and material of the exterior portion 20 at each location.

The welding area P is an area where the leg elastic member 27 is arranged. The welding region Q is a region at the lower end of the region on the back side of the diaper 1 where the back side exterior member 22 and the absorbent main body 10 overlap in the thickness direction. The welding region Y on the ventral side of the diaper 1 is the region where the ventral exterior portion 21 and the absorbent main body 10 overlap in the thickness direction, excluding the upper end portion. The welded area Y on the back side of the diaper 1 is the area where the back side exterior part 22 and the absorbent main body overlap in the thickness direction, excluding the upper end area and the welded area Q. The welding region X is approximately the entire area of the exterior member 20 excluding the welding region Y, the welding region P, the welding region Q, and the region where the waist elastic member 26 is arranged. Although the diaper 1 does not have the welded portion 25 in the area where the waist elastic member 26 is placed, the welded portion 25 may be provided in this area. When the welded part 25 is provided in the region where the waist elastic member 26 is arranged, it is more preferable to arrange the welded part 25 so that it does not cut the waist elastic member 26.

In the ventral side portion of the diaper 1, the ventral first region F1 is a region where the welded region The third region F3 on the ventral side is the region where the welding region The fourth ventral region F4 is a region where the welded region Y and the absorbent core 11 do not overlap (the coarsely shaded region in FIG. 8).

The followability in the left-right direction of each region of the first ventral region F1, the second ventral region F2, and the third ventral region F3 will be compared. The ventral first region F1 does not overlap the absorbent core 11 in the thickness direction, and the elastic modulus of the exterior portion 20 in the welded region X is large, so it has high followability when worn. On the other hand, since the second ventral region F2 and the third ventral region F3 overlap the absorbent core 11 in the thickness direction, they have lower followability when worn than the first ventral region F1.

If the ratio of the area of the welded portion per unit area in the welded region are the same, the followability of the second ventral region F2 and the third ventral region F3 when worn is approximately the same. In this case, the difference in followability between the second ventral region F2 and the third ventral region F3 and the first ventral region F1 when worn becomes large.

Therefore, the area ratio of the welded part 25 per unit area of the ventral second region F2 is set to be the same as the area ratio of the welded part 25 per unit area of the ventral first region F1, and the The ratio of the area of the welded part 25 per unit area is made larger than the ratio of the area of the welded part 25 per unit area of the ventral first region F1. As a result, the elastic modulus of the exterior portion 20 in the second ventral region F2 of the ventral exterior portion 21 becomes larger than the elastic modulus of the exterior portion 20 in the third ventral region F3. The followability when wearing the second ventral region F2, which includes the ventral exterior portion 21 having a larger elastic modulus, is greater than the followability when wearing the third ventral region F3. By arranging the second ventral region F2 between the first ventral region F1 and the second ventral region F2 in the vertical direction, the followability when worn is improved from the first ventral region F1 to the second ventral region F2. It is possible to gradually reduce the size toward the third area F3. That is, on the ventral side of the diaper 1, the ventral second region F2 becomes a buffer region between the ventral first region F1 and the ventral third region F3, and the ventral first region F1 and the ventral third region F3. By gradually reducing the difference in followability when worn, it is possible to easily reduce discomfort felt by the wearer, such as in tightness.

Similarly, on the back side of the diaper 1, the first back region R1 is a region where the welding region is a region where the welding region The fourth region R4 on the back side is a region where the welding region Y and the absorbent core 11 do not overlap (the coarsely shaded region in FIG. 8).

Regarding the back side of the diaper 1, the ratio of the area of the welded portion 25 per unit area of the second back region R2 is the same as that of the first back region R1, and the ratio of the area of the welded part 25 per unit area of the third back region R3 is the same as that of the first back region R1. The area ratio of the portion 25 is made larger than that of the first dorsal region R1. As a result, the elastic modulus in the second dorsal region R2 of the dorsal exterior portion 22 becomes larger than the elastic modulus in the third dorsal region R3, so the second dorsal region includes the dorsal exterior portion 22 having a larger elastic modulus. The followability when wearing R2 is greater than the followability when wearing the third dorsal region R3. By arranging the second dorsal region R2 between the first dorsal region R1 and the second dorsal region R2 in the vertical direction, the followability when worn is improved from the first dorsal region R1 to the dorsal side. It can be made smaller stepwise toward the third region R3. In other words, on the back side of the diaper 1, the second back region R2 becomes a buffer area between the first back region R1 and the third back region R3, and the difference in followability when worn is absorbed by the second back region R2. R2 becomes easier to buffer. Then, it becomes easier to reduce the possibility that the wearer may feel uncomfortable due to the difference in followability between the first dorsal region R1 and the third dorsal region R3 when worn.

At the center line CC in the left-right direction of the diaper 1 in the stretched state shown in FIG. It is preferable that it is long (df2<dr2). Since the back side of the diaper 1 is the part that comes into contact with the buttocks and waist of the wearer, it needs to be deformed into a shape that corresponds to the shape of the body. However, if the difference in followability between the first dorsal region R1 and the third dorsal region R3 when worn increases, the wearer may feel uncomfortable. On the other hand, by making the length dr2 of the second dorsal region F2 in the vertical direction longer, the followability when worn is improved compared to when the length dr2 of the second ventral region F2 in the vertical direction is less than or equal to the length df2 of the ventral second region F2. It becomes easier to gradually reduce the size from the first dorsal region R1 to the third dorsal region R3, and the second dorsal region F2 follows the first dorsal region R1 and the third dorsal region R3 when worn. This makes it easier to buffer the difference between In addition, in the diaper 1, the length dr3 in the vertical direction of the third dorsal region R3 is longer than the length df3 in the vertical direction of the third ventral region F3 on the center line in the left-right direction.

Further, it is preferable that the absorbent core 11 has a low basis weight region 30 in the second ventral region F2. Similarly, it is preferable to have the low basis weight region 30 in the second back region R2. As described above, the provision of the low basis weight region 30 serves as a starting point for folding the absorbent core 11, making it easier to deform the absorbent core 11. That is, although the low basis weight region 30 is provided to have a shape that matches the wearer's body, the low basis weight region 30 is also effective for improving 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. In other words, the low basis weight region 31 is a region having a lower basis weight than the surrounding area, and therefore has lower rigidity than the surrounding area. Therefore, by providing the low basis weight region 31 in the second ventral region F2 (second dorsal region R2), the followability of the second ventral region F2 (second dorsal region R2) when worn is increased. This makes it easier to increase the difference in followability when wearing the ventral third region F3 (dorsal third region R3), and to reduce the difference between the followability when wearing the ventral first region F1. This makes it easier to reduce the followability during wearing more gradually from the ventral first region F1 (dorsal first region R1) toward the ventral third region F3 (dorsal third region R3).

Furthermore, it is preferable that the absorbent core 11 has a low basis weight region 30 in the third region F3 on the ventral side. As shown in FIG. 8 and the like, a plurality of low basis weight regions 31 are provided in the third ventral region F3 at intervals in the left-right direction. Since the absorbent core 11 has the low basis weight region 31 not only in the second ventral region F2 but also in the third ventral region F3, the rigidity of the absorbent core 11 itself, which overlaps with the ventral exterior portion 21, is further increased. It can be lowered. This makes it possible to further reduce the difference in followability between the first ventral region F1 and the third ventral region F3 when worn, making it easier to reduce the discomfort felt by the wearer. Similarly, it is preferable that the absorbent core 11 has a low basis weight region 31 in the third region R3 on the back side.

It is more preferable that the number of low basis weight regions 30 in the left-right direction of the low basis weight regions 31 provided in the third ventral region F3 or the third dorsal region R3 is greater at the upper end than at the lower end. Specifically, in the diaper 1 shown in FIG. 8 etc., the number of low basis weight regions 31 provided at the upper end of the third ventral region F3 is 6, and the number of low basis weight regions 31 provided at the lower end thereof is 6. is 2 and the low basis weight region 32 is 1, for a total of 3. The number of low basis weight regions 31 provided at the upper end of the third back region R3 is six, and the number of low basis weight regions 30 provided at the lower end is five. Thereby, the followability of the upper end portion of the third ventral region F3 that is closer to the second ventral region F2 can be made greater than the followability of the lower end portion of the third ventral region F3 that is closer to the third ventral region F3. In other words, since the followability when worn can be gradually reduced from the upper end to the lower end within the third ventral region F3, the followability when worn in the second ventral region F2 and the third ventral region F3 is The gender difference can be reduced, and it becomes easier to gradually reduce the followability when worn from the first ventral region F1 to the third ventral region F3. This can reduce the discomfort felt by the wearer due to the difference in followability between the first ventral region F1 and the third ventral region F3 when worn. Regarding the number of low basis weight regions 30 in the third dorsal region R3, it is more preferable that the number of low basis weight regions 30 is greater in the upper end than in the lower end, similarly to the number of low basis weight regions 30 in the third ventral region F3.

Regarding the fourth ventral region F4, since the welded region Y and the absorbent core 11 do not overlap, the contraction force in the left-right direction of the fourth ventral region F4 is the same as that between the welded region Y and the absorbent core 11. This is larger than the contractile force in the left-right direction of the third ventral region F3, which is the overlapping region. In addition, since the fourth ventral region F4 is the welding region Y and overlaps with the absorbent main body 10, the followability when wearing the fourth ventral region F4 is lower than that when wearing the first ventral region F1. It is smaller than the followability in time. On the ventral side of the diaper 1, regarding a region that overlaps with the third ventral region F3 in the left-right direction, the fourth ventral region F4 is adjacent to the third ventral region F3 from the outside of the third ventral region F3 in the left-right direction. , the first ventral region F1 is adjacent to the fourth ventral region F4 from the outside of the fourth ventral region F4 in the left-right direction. From this, it can be seen that the region that overlaps with the third ventral region F3 in the left-right direction has a smaller contractile force than the first ventral region F1, and in the left-right direction from the first ventral region F1 to the third ventral region F3. The ventral fourth region F4, which has a greater followability when worn than the ventral third region F3, can be made smaller in stages, making it easier to buffer the ventral fourth region F4, which has greater followability when worn than the ventral third region F3. It is possible to reduce the sense of discomfort given to the wearer due to the difference in followability when the wearer wears the wearer.

Similarly, regarding the fourth dorsal region R4, since the welded region Y and the absorbent core 11 do not overlap, the followability of the fourth dorsal region R4 when worn is determined by the welded region Y and the absorbent core 11. The followability is greater than that of the third dorsal region R3, which is the region overlapping with No. 11, when worn. Furthermore, since the fourth dorsal region R4 is a welding region Y and overlaps with the absorbent main body 10, the contraction force of the fourth dorsal region R4 in the left-right direction is equal to that of the first dorsal region R1. It is smaller than the followability when worn. In the dorsal part 10R, in a region that overlaps with the third dorsal region R3 in the left-right direction, the fourth dorsal region R4 is adjacent to the third dorsal region R3 from the outside of the third dorsal region R3 in the left-right direction, The first dorsal region R1 is adjacent to the fourth dorsal region R4 from the outside of the fourth dorsal region R4 in the left-right direction. From this, it can be seen that the region that overlaps with the third dorsal region R3 in the left-right direction has a smaller followability than the first dorsal region R1, and in the left-right direction from the first dorsal region R1 to the third dorsal region R3. This makes it easier for the fourth dorsal region R4, which has greater followability than the third dorsal region R3, to provide a buffer, so that the distance between the first dorsal region R1 and the third dorsal region R3 It is possible to reduce the sense of discomfort given to the wearer due to the difference in followability when worn.

Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to be interpreted as limiting the present invention. Further, the present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

In the embodiment described above, the first region (F1, R1), the second region (F2, R2), and the third region (F3, R3) were provided in the ventral part 10F and the dorsal part 10R, respectively. Not limited to. Each region may be provided in either the ventral part 10F or the dorsal part 10R. It may be determined as appropriate depending on the stress acting on the exterior portion 20 (21, 22) and the absorbent core 11 depending on the magnitude of the elastic modulus of the stretchable sheets 215, 225.

Further, in the above embodiment, the welded portion 25 is circular (25a, 25d) or rectangular (25b, 25c), but is not limited to this. The shape of each welded portion 25 can be any shape such as an ellipse or a polygon. Further, welded portions 25 having different shapes may be provided even within the same area.

1 Pants-type disposable diaper (diaper, pants-type absorbent article), 1a Waist opening, 1b Leg opening, 10 Absorbent main body, 10F Ventral part, 10R Dorsal part, 11 Absorbent core, 11A Lower abdominal position, 11B Inseam Part, 11C buttock part, 11c waist part, 11t convex part, 12 top sheet, 13 back sheet, 14 side sheet, 20 exterior part, 21 ventral exterior part (waist part, ventral waist part), 21s front elastic area, 213 Skin-side sheet (non-stretchable sheet), 214 Non-skin-side sheet (non-stretchable sheet), 215 Stretchable sheet, 22 Back-side exterior part (waistline part, back-side waistline part), 22s Back-side stretchable area, 223 Skin-side sheet (non-stretchable sheet), 224 Non-skin-side sheet (non-stretchable sheet), 225 Elastic sheet, 23 Inseam exterior part, 23s Inseam elastic region, 231 Skin-side sheet, 232 Non-skin-side sheet, 233 Elastic elastic sheet, 24 end joining region, 25 welded portion, 25a, 25b, 25c, 25d welded portion, 26 waist elastic member, 27 leg elastic member, 28 inseam elastic member, 30 low basis weight region, 31 low basis weight region , 31h upper and lower low basis weight areas, 31s left and right low basis weight areas, 32 central low basis weight area, 40 leakage prevention wall section, 41 leakage prevention wall elastic member, 42 leakage prevention wall elastic member, CL predetermined position, F1 ventral side first 1 region, F2 ventral second region, F3 ventral third region, R1 dorsal first region, R2 dorsal second region, R3 dorsal third region, P welding region, Q welding region, X welding region ( (low area ratio area), Y welding area (high area ratio area)

Claims (6)

It has a vertical direction, a horizontal direction, and a front-back direction that intersect with each other,
an absorbent main body including an absorbent core arranged along the vertical direction and bent in the front-back direction at a lower end in the vertical direction;
an exterior part including a pair of waist circumference parts and located on the non-skin side of the absorbent main body;
A pants-type absorbent article having
In the lower end portion, the side edges in the left and right direction of the absorbent main body are located outside the side edges in the left and right direction of the exterior part,
In at least one of the pair of waist portions,
comprising a non-stretchable sheet and a stretchable sheet that stretches in the left-right direction,
The non-stretchable sheet and the stretchable sheet are welded in the front-rear direction by a plurality of welded parts,
In the extended state,
having a low area ratio region in which the area ratio of the welded part per unit area is a predetermined value, and a high area ratio area where the area ratio of the welded part per unit area is larger than the low area ratio region,
Of the one girth part,
An area that does not overlap with the absorbent core in the low area ratio area is defined as a first area,
A region where the low area ratio region and the absorbent core overlap is a second region,
If the region where the high area ratio region and the absorbent core overlap is defined as a third region,
In the center part in the left-right direction,
The second region is provided between the first region and the third region in the vertical direction ,
If the area where the high area ratio area and the absorbent core do not overlap is defined as a fourth area,
The fourth region is adjacent to the third region from the outside of the third region in the left-right direction,
The pants-type absorbent article is characterized in that the first region is adjacent to the fourth region from the outside of the fourth region in the left-right direction . The pants-type absorbent article according to claim 1,
The pants-type absorbent article is characterized in that the absorbent core has a low basis weight region in the second region where the average basis weight is lower than the surrounding area. The pants-type absorbent article according to claim 2,
The pants-type absorbent article is characterized in that the absorbent core has a low basis weight area in the third area as well, where the average basis weight is lower than the surrounding area. The pants-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,
In the left-right direction, the number of low basis weight regions provided at the upper end of the third region is greater than the number of low basis weight regions provided at the lower end of the third region. Pants-type absorbent article. The pants-type absorbent article according to any one of claims 2 to 4,
The pants-type absorbent is characterized in that the low basis weight region has a top and bottom low basis weight region having a first length in the vertical direction, and a left and right low basis weight region having a second length in the left and right direction. Sex items. The pants-type absorbent article according to any one of claims 1 to 5 ,
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,
A pants-type absorbent article, wherein the length of the second region of the dorsal waistline portion in the vertical direction is longer than the length of the second region of the ventral waistline portion.

Images