HK1236797B - Absorbent article - Google Patents

Description

absorbent articles

Technical Field

The present invention relates to an absorbent article, in particular to a disposable diaper or absorbent pad.

Background Art

Various improvements have been made to absorbent articles such as disposable diapers (hereinafter, also simply referred to as "diapers") in an effort to enhance their functionality and wearing comfort.

Absorbent articles absorb most of the discharged body fluids through the absorbent body. Here, because diapers cover the abdomen, buttocks, and thighs, they are affected by various body movements, especially leg movements, such as walking, turning over, and babies crawling. In particular, the absorbent body is sometimes twisted, folded, or torn due to various body movements. This reduces the fit of the diaper to the crotch, which can easily cause fluid leakage. Therefore, in order to maintain the fit, the non-skin contacting side of the absorbent body is embossed, as shown in Patent Document 1. In this way, by embossing the absorbent body, the rigidity of the absorbent body is strengthened, and the absorbent body is not easily twisted or torn by the forces applied by body movements.

On the other hand, although the absorbent body of a disposable diaper is located under the wearer's entire crotch, during urination, urine diffuses from the vicinity of the urination site along the front sheet or the absorbent body. To promote this diffusion, Patent Document 2 describes the following method: two recesses are provided along the longitudinal direction of the absorbent body in the crotch portion of the absorbent body to utilize these recesses to diffuse urine.

Furthermore, there is also a diaper in which, as shown in Patent Document 3, the skin contacting surface of the absorbent body is provided with embossing of compressed grooves in a grid pattern extending obliquely with respect to the direction from the front piece to the back piece of the diaper.

By embossing the absorbent body in this manner, the diaper's fit around the crotch is improved, thereby suppressing bodily fluid leakage. In particular, the absorbent body embossed with a pattern having components extending in an oblique direction, as disclosed in Patent Document 3, follows the forward and backward movement of the legs and the roundness of the buttocks, thereby also improving fit around the crotch.

In addition, this embossing process is formed by rotating an embossing roller with a protruding embossed pattern on the surface on a long absorbent sheet. During diaper manufacturing, after the embossing roller is rotated on the long absorbent sheet, various sheets are stacked and cut into the required size.

Background Art Literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2014-69002

Patent Document 2: Japanese Patent Application Laid-Open No. 2012-143535

Patent Document 3: Japanese Patent Application Laid-Open No. 2015-16218

Summary of the Invention

Disposable diapers are typically worn by infants and elderly individuals who require care, who are unable to defecate on their own. Therefore, diaper changes are often made at the discretion of their caregivers, not the wearer's own will. Parents, caregivers, and other individuals may see or feel the diaper bulge from urine absorption and change it.

Furthermore, many diapers use a mixture of pulp and super absorbent polymer (hereinafter also referred to as "SAP") in the absorbent body. However, due to the influence of SAP, the diapers tend to swell after absorbing urine.

As disclosed in Patent Document 1, without liquid diffusion on the skin-contacting side of the absorber, urine often fails to diffuse rapidly throughout the absorber and remains near the urination site. In this case, even with a small amount of urine, such as a single urination, the urination site of the absorber bulges, necessitating replacement. Consequently, the entire absorber is discarded without being effectively utilized.

Furthermore, as disclosed in Patent Document 2, even if a recess is provided on the skin-contacting side of the absorbent body to promote urine diffusion on the absorbent body, the recess is formed solely by compression of the absorbent body, and thus may be crushed by the wearer's weight when standing up, for example. Furthermore, even if the recess is not crushed, if the absorbent body near the wall of the recess absorbs liquid (urine), the absorbent body in that area will significantly expand, narrowing the recess and making it difficult for urine to diffuse rapidly to adjacent absorbent bodies, thus preventing urine from moving away from the vicinity of the urination site.

This time, we discovered that the diffusion of liquid within the absorbent is significantly affected by its density. Specifically, if the absorbent is highly compressed and its density is too high, the spaces where liquid can accumulate become smaller, making absorption difficult. On the other hand, if the density is too low, while liquid can be absorbed, the presence of spaces within the absorbent prevents further diffusion from that area. As a result, urine accumulates in the less dense areas adjacent to the longitudinal recesses, creating a bulge in the crotch area.

As described above, if urine does not quickly diffuse throughout the entire absorbent body and stays near the urination site, the absorbent body in the urination site swells, causing it to become hot and sticky, and the wearer may feel uncomfortable.

In addition, although the diaper is in a state that can still absorb urine, the diaper is changed by the user because the vicinity of the urination part swells. Therefore, the absorbent body as a whole cannot be effectively utilized and the diaper is thrown away, which is uneconomical.

Furthermore, even if the person changing the diaper sees or touches the area near the urination site and does not change the diaper, the absorbent core, which has swelled due to absorption of water, will become more distorted or more likely to tear than when dry. Therefore, if the urine does not spread during the first urination and the absorbent core near the urination site swells significantly, subsequent body movements may cause the absorbent core to tear. Further urination in the torn area may cause urine to flow through the cracks, causing leakage.

A first object of the present invention is to provide an absorbent article that rapidly diffuses body fluids to effectively utilize the entire absorber, and that suppresses stuffiness and distortion after absorption of body fluids to reduce discomfort felt by the wearer.

However, in order to prevent the groove from collapsing even when subjected to pressure caused by the wearer's weight, the inventors compressed the front sheet together with the absorbent body from the side of the front sheet (top sheet) disposed on the skin-contacting side of the absorbent body, thereby forming a compressed groove that is less likely to collapse. In this case, as described above, the compressed groove is formed by rotating the embossing roller on the absorbent body after the front sheet is stacked. When the compressed groove is formed in this way, the front sheet located on a higher layer than the absorbent body sinks toward the groove due to the rotation of the embossing roller, and the front sheet becomes strongly stretched. In particular, an embossed pattern having a component extending in an oblique direction, such as an oblique grid, has a portion where the distance between the locations compressed at the same time, such as near the grid points, becomes shorter (the interval becomes narrower). If the distance between the locations compressed at the same time becomes shorter, the force that stretches the front sheet from both sides of the adjacent compressed locations acts strongly, and the front sheet is easily stretched.

Since the compressed grooves themselves are located lower than uncompressed areas, they don't come into direct contact with the wearer's skin. However, near the grid points, i.e., the corners of the grids, the topsheet and absorbent core are stretched and strongly tightened. Consequently, the powdered superabsorbent polymer (SAP) in the absorbent core sometimes comes into contact with the topsheet. As a result, the corners of the grids on the skin-contacting surface of the topsheet convey the uneven texture of the superabsorbent polymer, making it harder than other areas.

Because the corners of the lattice are located higher than the bottom of the compression grooves, they come into contact with the wearer's skin, giving the wearer a hard or uneven feel, which is undesirable. Diapers, in particular, require a soft feel to the skin because they come into contact with delicate skin, such as the crotch. If the corners of the lattice are hard, the feel of contact with the skin is unpleasant.

A second object of the present invention is to provide an absorbent article having an embossed pattern having components extending in an oblique direction by compressing a front sheet together with an absorbent body, which provides a soft touch to the wearer's skin even at portions where the components extending in the oblique direction intersect.

The absorbent article of the present invention is characterized in that it has a liquid-permeable front sheet, a liquid-impermeable back sheet, and an absorbent body arranged between the front sheet and the back sheet, and a plurality of compression columns extending on the front sheet side, wherein the compression columns are arranged with a plurality of recesses formed by compressing the front sheet and the absorbent body, and the plurality of compression columns form intersection areas that intersect with each other, and no compressed recesses are formed in the intersection areas.

The absorbent article of the present invention provides a concave portion with a higher compression density of the absorbent body in the flow channel for the circulation of body fluids such as urine. Even in the flow channel, the absorbent body has a compression density difference. Therefore, when a relatively large amount of body fluid is discharged at one time, the body fluid can be quickly diffused and absorbed through the flow channel, thereby effectively using the entire absorbent body.

Furthermore, the absorbent article of the present invention can provide an absorbent article that gives a soft touch to the wearer's skin even in the intersection region where a plurality of compressed rows intersect each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective projection diagram showing the appearance of an embodiment in which the absorbent article of the present invention is applied to an open-type disposable diaper.

FIG. 2 is a perspective projection diagram of the lower body of a person wearing the diaper shown in FIG. 1 , as viewed from the back.

FIG3 is a partially cutaway plan view of the diaper shown in FIG1 when it is unfolded and viewed from the skin contacting surface side.

FIG. 4 is a cross-sectional view of the diaper shown in FIG. 3 taken along line IV-IV.

FIG. 5 is a perspective projection diagram showing the diaper shown in FIG. 1 unfolded and exploded.

FIG. 6 is a partial top view of the absorbent body portion of the diaper shown in FIG. 1 as viewed from the top sheet side.

FIG. 7 is a partial enlarged top view showing an enlarged flow channel portion of the partial top view shown in FIG. 6 .

FIG8 is a cross-sectional view taken along line VIII-VIII of FIG7 .

FIG9 is a cross-sectional view taken along line IX-IX of FIG7 .

FIG. 10 is a diagram showing another example of the flow channel arrangement pattern.

FIG. 11 is a diagram showing another example of the flow channel arrangement pattern.

FIG. 12 is a diagram showing another example of the flow channel arrangement pattern.

FIG. 13 is a cross-sectional view showing another example of the diaper, taken along the same cutting line as line VIII-VIII in FIG. 7 .

FIG. 14 is a partial top view showing another example of the diaper of FIG. 1 , showing the absorbent body portion as viewed from the top sheet side.

FIG. 15 is a schematic partial plan view showing the oblique grid-shaped embossed pattern portion of FIG. 14 .

FIG. 16 is a partially enlarged plan view showing a portion of FIG. 15 .

FIG17 is a cross-sectional view taken along line XVII-XVII of FIG16 .

FIG18 is a cross-sectional view taken along line XVIII-XVIII of FIG16 .

FIG. 19 is a diagram illustrating a method of forming a recessed portion.

FIG. 20 is a diagram showing another example of a method for forming a recessed portion.

DETAILED DESCRIPTION

An embodiment of the absorbent article of the present invention will be described in detail with reference to FIG. 1 to FIG. 20 .

[First embodiment]

Regarding the appearance of a first embodiment of the present invention applied to an unfolded disposable diaper (so-called sheet-type disposable diaper), FIG1 shows a perspective view from the front side, and FIG2 shows a perspective view from the back side. FIG2 shows the lower body posture of an infant wearing this unfolded disposable diaper, as viewed from the back side. FIG3 shows a top view of the diaper shown in FIG1 unfolded and viewed from the skin-contacting side. FIG4 shows a cross-sectional view taken along line IV-IV of FIG3. Furthermore, FIG5 shows the unfolded disposable diaper shown in FIG1 and FIG2 in a divided state after being cut and unfolded.

The unfolded disposable diaper (hereinafter sometimes referred to as a "diaper") 10 of this embodiment includes a front body region 10F, a back body region 10R, and a crotch region 10C connecting the front body region 10F and the back body region 10R. Furthermore, a waist opening 10W is formed so that the front body region 10F and the back body region 10R surround the wearer's waist when worn. Similarly, a pair of left and right leg openings 10L are formed in the crotch region 10C at the lower ends of the front body region 10F and the back body region 10R, so that the crotch region 10C surrounds the wearer's thighs.

As shown in Figure 2, when worn, the front body region 10F is positioned on the wearer's ventral side, while the back body region 10R is positioned on the wearer's dorsal side. Furthermore, the crotch region 10C covers the wearer's crotch, allowing the wearer's legs to pass through a pair of left and right leg openings 10L. Therefore, the leg openings 10L are positioned anywhere along the wearer's legs, from the base of the legs to near the thighs.

When the diaper 10 is properly worn, a line running along the wearer's central body axis from head to crotch is referred to as an imaginary line P, which will be used as needed in the following description. As shown in Figures 1 and 2, the imaginary line P extends from the ventral side toward the dorsal side of the diaper 10 through the crotch. Specifically, if the waist of the diaper 10 is considered the top and the crotch is considered the bottom, the imaginary line P extends along the surface of the diaper 10 in a vertical direction, and also extends in a vertical direction on the dorsal side through the crotch. In other words, the vertical direction is along the wearer's central body axis from head to crotch, and the imaginary line P extends along the central body axis.

A pair of left and right fastening tapes 10A are attached to the left and right edge portions of the back body region 10R of the cover sheet 11 located on the outside of the diaper 10. These tapes overlap the left and right edge portions of the front body region 10F when worn, connecting them to form leg openings 10L. The fastening tapes 10A are attached to the front patch sheet 10B attached to the cover sheet 11 in the front body region 10F in a removable manner. Furthermore, an elastic sheet 10D is attached to the upper end of the back body region 10R of the cover sheet 11. This elastic sheet 10D extends along the width of the cover sheet 11 and is used to provide a comfortable fit around the wearer's waist.

As shown in Figures 3 to 5, the diaper 10 of this embodiment is formed by overlapping and joining, in order from the outside, a covering sheet 11, a backsheet 12, an absorbent body 13, and a topsheet 14 that contacts the wearer's skin. A pair of semicircular notches 11A, forming leg openings 10L, are formed on the left and right sides of the crotch region 10C of the covering sheet 11. The liquid-impermeable backsheet 12 is joined to the inner covering sheet 11B, and the absorbent body 13 is disposed between the backsheet 12 and the liquid-permeable topsheet 14. The topsheet 14 is joined to the backsheet 12 via the absorbent body 13. To achieve a good feel, rubber threads 15 for forming leg gathers are joined in an extended state between the outer covering sheet 11C and the inner covering sheet 11B, each formed of a relatively thin nonwoven fabric.

Liquid-impermeable side sheets 18 are bonded to the left and right edges of the liquid-permeable top sheet 14 of this embodiment. Rubber cords 19 for forming three-dimensional pleats are bonded to the inner edges of the left and right side sheets 18 in a stretched state. As shown in FIG3 , the side sheets 18 are stretched in the longitudinal direction by the expansion and contraction of the rubber cords 19. As shown in FIG4 , the three-dimensional pleats are formed, with the inner edges standing upright.

In the diaper 10 of this embodiment, the absorbent body 13 is elongated along an imaginary line P, with the longitudinal direction thereof being parallel to the imaginary line P. Furthermore, the direction perpendicular to the imaginary line P is defined as the width direction. The ratio of the longitudinal direction to the width direction of the diaper 10 is not limited to that of this embodiment. This ratio can be appropriately modified depending on the wearer's body shape.

FIG. 6 is a partial top view of the crotch portion of the diaper 10 as viewed from the topsheet 14 side.

In addition, the portion shown in the figure, that is, the top sheet 14 and the absorbent body 13 of the diaper 10 are collectively referred to as the "absorbent portion".

The absorbent body 13 of the present embodiment, which is located below the top sheet 14, mainly comprises pulp and super absorbent polymer (hereinafter also referred to as "SAP"). The amount of pulp per unit area of the absorbent body 13 of the present embodiment is 185 g/ ^m2 , and the amount of SAP is 228 g/ ^m2 . It is preferred to mix the pulp and SAP in such a way that the weight ratio of SAP in the weight of the absorbent body (the total weight of pulp and SAP) is greater than 20% and less than 80%. Since SAP can increase the amount of liquid absorbed without increasing the amount of pulp, a large amount of liquid can be absorbed by a thinner absorbent body 13 by adding SAP. However, if the amount of SAP is too much, gel blocks are easily generated due to the combination of the SAP that swells after absorbing the liquid, which is not good. On the contrary, if the amount of SAP is too little, the amount of liquid that can be absorbed is reduced, and therefore, liquid leakage is easily caused.

The absorber 13 is elongated and slender, extending across the front, crotch, and back sections. Furthermore, it is divided into three sections: the front section M1, the crotch section M2, and the back section M3. In the crotch section M2, a pair of arc-shaped notches 13A are formed to match the left and right leg openings 10L that surround the thighs of the legs. Furthermore, the notches 13A may be formed regardless of the size of the absorber 13. While the absorber 13 of this embodiment is provided with the notches 13A and is hourglass-shaped, with the width of the center portion being narrower than the front and rear ends, the shape of the absorber of the present invention is not limited to this. If the direction from the front section to the back section is defined as the front-to-back (up-down) direction, and the direction orthogonal to this front-to-back (up-down) direction is defined as the left-to-right direction, various shapes may be included, such as a shape with the corners of the front and rear (up-down) ends cut into circles, an elliptical shape extending along the front-to-back (up-down) direction, a circular shape, or a rectangular shape with the same lengths in the front-to-back (up-down) and rear sections.

In the diaper 10 of this embodiment, in order to quickly diffuse discharged urine and other body fluids from the discharge location, flow channels 21 are formed by embossing in the absorption portion, which is originally a flat portion. The flow channels 21 divide the flat portion into a plurality of flat partitions 24.

The flow channels 21 are formed by regularly embossing from the surface of the top sheet 14 toward the absorbent body 13, thereby forming a plurality of compressed recessed portions arranged therein, and extending in an oblique lattice pattern over the entire area of the absorbent portion.

The flow channel 21 has the following structure.

Fig. 7 is an enlarged view of a portion of the flow channel 21 extending obliquely in a lattice pattern, Fig. 8 is a view showing a cross section taken along line VIII-VIII of Fig. 7, and Fig. 9 is a view showing a cross section taken along line IX-IX of Fig. 7.

As shown in FIG7 , a plurality of recesses 22 are arranged in a flow channel 21 having a width Q1. The recesses 22 are formed by intermittently compressing the top sheet 14 and the absorbent body 13 from the surface of the top sheet 14 using an embossed pattern such as dots. As shown in FIG8 , by arranging the recesses 22 at certain intervals, the absorbent body 13 near the recesses 22 is pressed downward, and the surrounding absorbent portion is also pressed downward, forming a space 22b that is recessed in a flat partition (hereinafter also referred to as a "main absorbent area") 24 without an embossed pattern. Therefore, by forming the recesses 22 at fixed intervals, a flow channel 21 consisting of the recesses 22 and the recessed space 22b can be formed.

The recess 22 is formed by placing an adhesive between the top sheet 14 and the absorbent body 13 and compressing the top sheet 14 and the absorbent body 13 together from the surface of the top sheet 14. A portion of the fibers of the top sheet 14 engage with the surface fibers of the absorbent body 13 and are firmly fixed. The thickness of the absorbing portion of the bottom surface 22a of the recess 22 is about 1/6 of the thickness when not compressed. The compression of the absorbent body 13 by compression is preferably set to a thickness of about 1/3 to 1/7 of the thickness when not compressed. In addition, the thickness of the absorbing portion of the concave space 22b around the recess 22 is about 1/4.5 of the thickness when not compressed.

Therefore, regarding the absorbent body density, the absorbent body 13 is divided into three sections: a compressed, high-density portion 13A (i.e., the bottom 22a of the recess 22); a low-density portion 13C (i.e., the non-embossed portion 24); and a medium-density portion 13B (i.e., the wall portion of the recess 22 and flow channel 21). Specifically, the medium-density portion 13B is not a uniform density, but rather a density-varying portion where the density gradually decreases from the bottom 22a to the non-embossed portion 24. Figure 8 shows the color change according to the compressed density of the absorbent body 13, with the compressed density gradually changing toward the main absorbent region (flat subregion) 24, such that the black portion near the bottom 22a of the recess 22 becomes lighter.

As described above, the absorbent body 13 mainly comprises SAP and pulp, and its density is mainly related to the density of the pulp fibers. Therefore, the high-density portion 13A is a state where the pulp is compressed and the gaps between the pulp fibers are small, while the low-density portion 13C is a state where the gaps between the pulp fibers are larger than those in the high-density portion 13A.

Furthermore, because the recesses 22 are formed by compressing and bonding the synthetic fiber topsheet 14 and the absorbent core 13, whose primary component is pulp, the bottom surface 22a of the recesses 22 is thin and absorbs little liquid. Consequently, liquid is hardly absorbed by the bottom surface 22a of the recesses 22 and flows away. Consequently, the bottom surface of the flow channel 21 alternates between the recesses 22 and the adjacent recessed spaces 22b formed by pressing down on the recesses 22, where the compression density of the absorbent core 13 differs. This allows liquid to flow forward and be absorbed from the recessed spaces 22b.

Furthermore, the liquid applied to the surface of the liquid-absorbing top sheet 14 passes through the top sheet 14 in the main absorption region (flat partition) 24 and is absorbed by the absorbent body 13. On the other hand, the liquid applied to the flow channel 21 flows along the flow channel 21 as described because the bottom surface 22a of the recess 22 is in the form of a film. In this flow, the liquid in the flow channel 21 is not absorbed at the bottom surface 22a because the bottom surface 22a of the recess 22 is in the form of a film, but penetrates the top sheet 14 along the wall surface toward the medium-density portion 13B. Secondly, the liquid that cannot be retained in the voids of the medium-density portion 13B flows into the low-density portion 13C, which has a larger void. In this way, the liquid advances from the medium-density portion 13B to the low-density portion 13C and is absorbed into the main absorption region (flat partition) 24.

In the absorbent body 13, the portion facing the urination area absorbs liquid fully because liquid is also directly applied to the main absorption area (flat partition) 24. However, the portion not facing the urination area absorbs liquid transported from the urination area through the top sheet 14 or the absorbent body 13 because liquid is not directly applied. Here, the flow channel 21 plays the role of causing the liquid to flow farther from the portion facing the urination area. That is, in the flow channel 21, since the recesses 22 that become the high-density portion 13A that does not absorb much liquid are formed at fixed intervals, the liquid flows in the flow channel 21 and flows farther from the urination area, thereby diffusing the liquid to the entire absorbent body 13. Here, urine is used as an example, but of course the same diffusion effect can be obtained for other body fluids such as menstrual blood.

Therefore, discharged liquid spreads within the absorbent portion through rapid diffusion on the surface layer as it flows along the flow channel 21, and slow diffusion as it penetrates the interior of the absorbent core 13 and slowly travels along the fibers of the absorbent core 13. Thus, the flow channel 21 is not formed simply by compressing the absorbent core 13. Instead, by compressing the absorbent core 13 together with the synthetic fiber top sheet 14, the bottom surface 22a is formed into a thin film, effectively forming the flow channel 21 and preventing it from being crushed by load. Furthermore, since the bottom surface 22a is thin and absorbs little liquid, it does not expand due to liquid absorption and thus block the flow channel 21, thus improving diffusion.

In order to quickly diffuse liquid from the crotch portion M2 facing the urination site, it is ideal that the flow channel 21 spreads in all directions. In this embodiment, as shown in Figure 6, the flow channel 21 extends from the crotch portion M2 in a strip-like shape along the length of the absorbent body 13, thereby enabling liquid to quickly move toward the ventral and dorsal sides of the absorbent body.

On the other hand, since urination excretes a large amount of urine at a time, diffusion through the flow channel 21 alone is insufficient, and absorption must occur in the main absorption region (flat subregion) 24. However, as mentioned above, the absorbent body 13 contains SAP. Therefore, when liquid is absorbed, the SAP expands and the expanded SAP bonds with each other, causing the absorbent body 13 to gel. In the gelled area, the gel acts as a barrier, preventing liquid from penetrating the absorbent body 13 located in front of it. Therefore, if the flat subregion 24 is too narrow, the entire absorbent body 13 within the subregion will gel, hindering the diffusion of liquid from the absorbent body 13 to the adjacent flat subregion 24, that is, the slow diffusion through the absorbent body 13.

Therefore, the area of one flat section 24 is preferably between 0.5 ^cm² and 50.0 ^cm² . More preferably, it is between 2 ^cm² and 18 ^cm² . To achieve this area range, the length of the diagonal line L1 of the flat section 24 shown in Figure 7 is 2 < L1 < 6. This size allows each flat section 24 to be fully utilized, and urine does not stagnate solely in the urination area.

If the area of a single flat section 24 is less than 2 ^cm² , the intervals between the flow channels 21 become narrower. Consequently, the flow channels 21, which feel harder than the flat sections 24, come into contact with the skin, causing discomfort to the user. Furthermore, all absorbent bodies 13 within the flat sections 24 in the crotch area M2 become gelled, unable to absorb further urine and forming a gel mass, which stagnates the slow diffusion of urine into adjacent absorbent bodies 13.

On the other hand, if the area of one flat section 24 is too large, diffusion through the flow channel 21 becomes rough, and the flat section 24 cannot be fully utilized. As a result, the absorber 13 cannot be used efficiently, which is not ideal.

Furthermore, as shown in FIG6 , the flow channel 21 is arranged in an oblique lattice shape throughout the absorbent body 13, so it has a plurality of intersections (intersection areas of the flow channel 21) 21D. By using the flow channel 21 branching at the intersection 21D, the liquid is further dispersed and spreads in all directions. In order to make the diffusion through the flow channel 21 more efficient, in this embodiment, there is no recess 22 at the intersection 21D of the flow channel (refer to FIG7 and FIG9 ). Since the intersection 21D of the flow channel faces the four main absorption areas (flat partitions) 24, if the liquid flows from the intersection 21D to each main absorption area (flat partition) 24, the diffusion effect is greater. Therefore, the recess 22 is not provided at the intersection 21D, but an environment is set to make it easier for the liquid to be absorbed into the main absorption area (flat partition) 24. That is, as shown in FIG9 , the compression density of the absorbent body 13 is lower than that of the bottom surface 22a of the recess 22 at the intersection 21D, and the liquid is absorbed. Furthermore, since the liquid moves toward the main absorbent regions (flat subregions) 24 of the absorbent core 13, which have a lower compression density, the liquid reaching intersection 21D spreads toward the main absorbent regions (flat subregions) 24 facing intersection 21D, as indicated by arrow A. Since intersection 21D faces four main absorbent regions (flat subregions) 24, rapid absorption and diffusion over a wide area is possible. Furthermore, adjacent main absorbent regions (flat subregions) 24 are not separated by recesses 22 at intersection 21D, allowing for the expected absorption and diffusion of the liquid through the absorbent core 13.

That is, in the portion facing the plurality (four) main absorption regions (flat partitions) 24, called the intersection 21D, the liquid is rapidly diffused and absorbed in all directions, thereby making it possible to effectively utilize each absorption region 24. As shown in FIG6 , the main absorption region (flat partition) 24 is surrounded by the flow channel 21 on at least one side and almost on all four sides. In the main absorption region (flat partition) 24, the liquid moves from the wall surface of the flow channel 21, that is, the medium-density portion 13B. If the liquid also enters from the intersection 21D in addition, the number of places where the liquid enters can be increased. If the liquid enters the main absorption region (flat partition) 24 from multiple directions, the entire main absorption region (flat partition) 24 can be effectively utilized. In this way, since the liquid can enter from multiple directions, even if the area of one partition of the main absorption region (flat partition) 24 is increased, the liquid can be fully absorbed to the central part of the region, compared to the case where the recess 22 is provided at the intersection 21D.

As described above, by distributing the flow channels 21 throughout the entire absorbent body 13 of the diaper 10, urine can be rapidly diffused from the urination site along the flow channels 21 to the entire absorbent body 13, thereby preventing urine from stagnating only in the urination site. Furthermore, the flow channels 21 have discontinuous recesses 22, but are instead distributed at regular intervals. This allows the flow to flow even on the bottom surface of the flow channels 21 while absorbing some liquid. In other words, liquid diffusion occurs in two layers: from the top sheet 14 side, in other words, the upper layer on the flow channel 21 side, and from the lower layer on the absorbent body 13 side. Furthermore, the rate of liquid diffusion within the flow channels 21 (i.e., the upper layer) is significantly faster than that within the absorbent body 13 (i.e., the lower layer). Therefore, the flow channels 21 allow liquid to move quickly, preventing large amounts of liquid from accumulating in specific areas.

Furthermore, by not providing the recess 22 at the branch point, i.e., the intersection 21D, urine is quickly absorbed into the four main absorption areas (flat partitions) 24 adjacent to the intersection 21D. Therefore, urine discharged at the urination site can quickly move from the urination site to a more distant location along the flow channel 21, and during the movement, is gradually absorbed by the adjacent main absorption areas (flat partitions) 24 from the wall surface of the flow channel 21. Furthermore, urine not only branches to other flow channels 21 that intersect at each intersection 21D that appear midway along the path, but also diffuses to the adjacent main absorption areas (flat partitions) 24. In this way, the discharged urine quickly diffuses in all directions from the urination site, so that the urine does not stagnate at the urination site, but is absorbed in a wider area of the absorbent body 13. Therefore, it is possible to prevent the absorbent body 13 near the urination site from expanding significantly due to one urination, and to prevent the absorbent body 13 from being replaced even though the absorbent body 13 as a whole still has absorption capacity. Furthermore, since urine does not stagnate at the urination site, it is possible to prevent the urination site from becoming stuffy. Furthermore, since the area of each main absorbent region (flat region) 24 can be increased, the majority of the surface that contacts the skin can be provided with a smooth and soft surface of the main absorbent region (flat region) 24 without embossing. This allows urine to be quickly spread over a wider area while maintaining a good feel against the skin.

As described above, by dividing the absorption portion into a plurality of flat sections 24 using the flow channels 21, liquid diffusion is improved and absorption without leakage of liquid can be maintained. Therefore, it is possible to suppress the absorbent body 13 near the urination area from significantly expanding due to a single urination and replacing the absorbent body 13 even though the absorbent body 13 as a whole still has absorption capacity.

In other words, by covering the entire area of the absorbent body 13 of the diaper 10 with the flow channels 21, urine quickly diffuses from the urination site along the flow channels 21 to the entire absorbent body 13. Furthermore, since the flow channels 21 are formed by compressing the top sheet 14 and the absorbent body 13 together, with at least a portion of the bottom surface being formed into a thin film, the bottom surface is less likely to absorb liquid, thereby preventing blockage of the flow channels due to the absorbent body swelling after absorbing liquid, as would be the case if the absorbent body were simply compressed.

Furthermore, by adopting a two-layer diffusion structure with slow diffusion through the absorbent body 13, diffusion is achieved using the entire thickness direction of the absorbent body 13. In addition, the liquid diffusion rate in the flow channel 21 (i.e., the upper layer) is significantly faster than the liquid diffusion rate in the absorbent body 13 (i.e., the lower layer). Therefore, the flow channel 21 is used to quickly move the liquid and prevent a large amount of accumulation in a specific area. On the other hand, a large amount of urine discharged in one urination must be quickly absorbed without leaking from the diaper 10. By setting a partition of the main absorption area (flat partition) 24 to a specified area, a large amount of urine is quickly absorbed, and the absorbent body in the partition is prevented from being completely gelled and forming a gel block, thereby maintaining the diffusion effect through the absorbent body to the adjacent flat partition.

Furthermore, since the recessed portion 22 is not provided at the intersection 21D, which is a branch point, urine is quickly absorbed into the four main absorption regions (flat sections) 24 adjacent to the intersection 21D.

Furthermore, returning to FIG. 6 , the flow channel 21 of this embodiment includes a first flow channel 21a extending obliquely toward one side in the width direction of the absorbent body 13 (the right side when viewed from the front in the figure), and a plurality of second flow channels 21b extending obliquely toward the other side (the left side when viewed from the front in the figure). The imaginary line P on the absorbent body 13 extends from the upper end of the front body portion M1 toward the lower end of the back body portion M3. Specifically, as shown in FIG. 6 , when the absorbent body 13 is elongated, it extends in the longitudinal direction. The flow channel 21 extends obliquely relative to the imaginary line P. That is, relative to a direction along the side with the imaginary line P as the axis, such as the longitudinal direction, the first flow channel 21a is inclined toward one side at an angle α, and the second flow channel 21b is inclined toward the other side at an angle β. Angle α and angle β may be the same or different. Furthermore, in FIG. 6 , the plurality of first flow channels 21a are inclined at the same angle and are arranged at fixed intervals. That is, the first flow channels 21a are parallel and arranged at fixed intervals. However, the present invention is not limited thereto, and may include a case where the groove intervals are not constant or the grooves have different inclination angles, as long as the predetermined area can be ensured in the flat partition 24. The same applies to the second flow channel 21b.

The absorber 13 is not limited to an elongated shape, and may be a square shape having the same length in both vertical and horizontal directions. In this case, the first grooves 21a and the second grooves 21b also extend obliquely with respect to the direction along the side.

In addition, the flow channel 21 may not only be inclined but also extend in a sideways direction.

The flow channel 21 does not need to extend to the ends of the diaper 10. If the flow channel 21 is provided only at the ends of the diaper 10, there is a possibility of liquid leakage from there, which is not desirable. Therefore, the flow channel 21 is not provided at the ends of the diaper 10, namely, at the leg openings 10L and the waist opening 10W.

In addition, it is preferable that the flow channel 21 does not extend to the edge of the absorbent body 13. If the direction from the front body portion M1 to the back body portion M3 is set as the front-to-back direction, no flow channel is formed at the front and rear ends. Similarly, if the left-right direction orthogonal to the front-to-back direction is set as the width direction, the absorbent body 13 has a flow channel forming area N1 in the central part of the longitudinal direction and the width direction, and has flow channel non-forming areas N2 on both sides thereof. In Figure 6, the two ends in the width direction of the absorbent body 13 are flow channel non-forming areas N2, and the flow channel forming area N1 extends in a strip shape from one end of the longitudinal direction represented by the imaginary line P toward the other end in the central part. In addition, the flow channel 21 does not reach the two ends in the longitudinal direction. In this way, by not providing the flow channel 21 at the ends of the absorbent body 13, liquid leakage along the flow channel can be reliably prevented.

Next, an example of a flow path pattern formed by embossing will be described.

As shown in Figure 6, the flow channel pattern of this embodiment is a grid pattern consisting of connected dot-shaped recesses 22. The flow channels 21 are arranged so that the length of the diagonal line L1 of a square (roughly equivalent to L1 shown in Figure 7) is 42.4 mm (4.24 cm). Furthermore, as shown in Figure 7, the diameter Q2 of the recesses 22 is 2.0 mm, and the spacing Q3 (the distance between the centers of adjacent recesses 22) between the recesses 22 is 2.0 mm. Furthermore, the distance Q4 between the centers of adjacent recesses 22 at the intersection 21D is 6.0 mm.

The thickness of the absorbent body 13 and the top sheet 14 before embossing is 8.0 mm, and as shown in FIG. 8 , the depth Q5 of the recessed portion 22 is approximately 5.0 mm.

The thickness of the absorbent body 13 and the top sheet 14 before embossing is preferably 5.0 mm to 20.0 mm. Furthermore, with respect to the configuration of the absorbent body 13 and the top sheet 14, the diameter Q2 of the recesses 22 is preferably 1.0 mm to 4.0 mm, the arrangement interval Q3 is preferably 1.0 mm to 9.0 mm, and the depth Q5 is preferably 2.0 mm to 10.0 mm. Furthermore, the distance Q4 between the centers of adjacent recesses 22 at the intersection 21D is preferably 2.0 mm to 12.0 mm.

Next, a comparison experiment of the liquid diffusing properties of the diaper having the flow channel pattern according to the present embodiment and the diaper not having such a flow channel pattern will be described.

A diaper with a flow channel pattern (Example 1) and a diaper without a flow channel pattern (Comparative Example 1) were placed on a doll. 50cc of water was injected into the crotch area three times, and the liquid diffusivity was compared. Specifically, the diaper was divided equally along the imaginary line P into five areas: the abdominal end, the central abdominal area, the crotch, the central back, and the back end. The weight of each area after each injection was measured to measure the liquid diffusivity. Furthermore, the ratio of the weight of each area after the three injections to the total weight of the diaper was calculated.

The total weight of the diaper before filling was 31.7 g.

Table 1 shows the results of Example 1, and Table 2 shows the results of Comparative Example 1.

[Table 1]

Example 1 1st time (g) 2nd time (g) 3rd time (g) Weight ratio after 3 times (%) Abdominal end 0.3 3.3 8.0 5.3 Central abdomen 12.2 30.4 40.3 26.9 crotch 25.3 33.7 53.0 35.3 Central dorsal region 11.9 29.2 39.7 26.5 Back end 0.3 3.4 9.1 6.0

[Table 2]

Comparative Example 1 1st time (g) 2nd time (g) 3rd time (g) Weight ratio after 3 times (%) Abdominal end 0.0 0.4 0.9 0.6 Central abdomen 9.1 32.1 45.6 30.4 crotch 33.7 40.6 64.5 43.0 Central dorsal region 7.2 26.5 37.9 25.3 Back end 0.0 0.4 1.2 0.8

As shown in Table 1, the diaper with the flow channel pattern of Example 1, which is the present embodiment, disperses liquid to the abdominal and dorsal ends of the absorbent body, while the weight ratio of the crotch area is lower than that of the comparative example. Therefore, it can be understood that the injected water does not remain in the crotch area at the injection site, but is dispersed throughout the absorbent body.

(Variation Example)

In the first embodiment, the flow channel 21 is an embossed pattern in which the recesses 22 are intermittently arranged. However, the present invention is not limited thereto, and the flow channel 21 may be formed by continuous embossing, that is, by continuous recesses 22 .

The flow channels 21 may be honeycomb-shaped (variation 1) instead of the oblique lattice shape as shown in Fig. 10. In this case, the area of the flat sections 24 surrounded by each flow channel 21 is also 0.5 ^cm2 or more and 50.0 ^cm2 or less.

Furthermore, although the first embodiment and the first modification do not provide the recessed portion 22 at the intersection 21D of the flow channel 21 , the present invention is not limited thereto, and the recessed portion 22 may be provided.

Furthermore, as shown in Figures 11 and 12, the flow channel 21 can also be curved (Variations 2 and 3) rather than being limited to a straight line. Alternatively, as shown in Figure 11, a pattern can be formed in which the main absorption regions (flat subregions) 24A and 24B surrounded by the curved flow channel 21 have different areas. In this case, there is no recess 22 at the intersection 21D. In this way, by not only forming the flow channel 21 in an oblique lattice shape, but also forming the flow channel 21 in a honeycomb or curved shape, the design effect created by processing the flow channel 21 can be achieved, thereby improving the aesthetics.

Alternatively, the flow channel 21 may be formed using an embossed pattern, where the lines corresponding to the flow channel 21 are formed by light compression, and the portions corresponding to the recesses 22 are repeatedly compressed. This pattern is achieved by combining lines corresponding to the flow channel 21 with dots corresponding to the recesses 22. In this case, the portions 22b of the flow channel 21 outside the recesses 22 are also formed by compression. However, it is believed that the difference in compression strength results in a density difference between the bottom surface 22a and the absorbent body 13. While the absorption effect of the portions 22b of the flow channel 21 outside the recesses 22 is reduced, the flow of fluid through the flow channel 21 is reliably ensured.

Furthermore, the recessed portion 22 may be formed not only of a circular shape but also of various shapes such as a semicircular shape, a quadrilateral shape, and a triangle shape.

Furthermore, the top sheet 14 may be disposed not only directly on the absorbent body 13 but also after the absorbent body 13 is covered with the hydrophilic sheet 13S.

Alternatively, as shown in Figure 13, a liquid diffusion sheet 13T, which enhances liquid diffusivity, may be placed between the top sheet 14 and the hydrophilic sheet 13S. This sheet facilitates the diffusion of bodily fluids. Furthermore, the hydrophilic sheet 13S may be installed so as to cover the absorbent core 13, or it may be positioned without covering the ends of the absorbent core 13 and simply overlapped on the front and back surfaces. Furthermore, the liquid diffusion sheet 13T may be positioned between the hydrophilic sheet 13S and the absorbent core 13. This sheet facilitates the diffusion of bodily fluids.

[Second embodiment]

Next, the structure of the absorbent body portion according to the second embodiment of the present invention will be described.

FIG. 14 is a partial top view of the portion where the absorbent body 13 and the top sheet 14 are located, as viewed from the top sheet 14 side.

The absorbent body 13 of the present embodiment, which is located below the top sheet 14, mainly comprises pulp and super absorbent polymer (hereinafter also referred to as "SAP"). The absorbent body 13 is elongated in shape so as to extend over the front body, crotch, and back body. Furthermore, it is divided into three parts: the front body part M1, the crotch part M2, and the back body part M3. In the crotch part M2, a pair of notches 13A in the shape of an arc are formed to match a pair of left and right leg openings 10L that surround the thigh parts of the two legs. In addition, the notch 13A may also be formed regardless of the size of the absorbent body 13. In addition, the absorbent body 13 of the present embodiment is provided with the notch 13A, and is hourglass-shaped in that the width of the central part is narrower than that of the front and rear ends, but the shape of the absorbent body of the present invention is not limited thereto. If the direction from the front body part to the back body part is set as the front-to-back (up-down) direction, and the direction perpendicular to the front-to-back (up-down) direction is set as the left-to-right direction, then various shapes are included, such as a shape in which the corners of the front and back (up-down) ends are cut into circles, an ellipse extending along the front and back (up-down), a circle, a rectangle with the same length in the front, back, up, down, left and right directions.

The absorbent body 13 is covered by a core sheet (gauze) not shown. The core sheet is a thin hydrophilic sheet. In this embodiment, the absorbent body 13 covered by the core sheet is used, but the absorbent body of the present invention may not be covered by the core sheet.

Furthermore, as shown in Figures 14 and 15, the diaper 10 has a compression forming area (embossed pattern forming area) N1 formed by compression based on a regular embossing process from the surface of the top sheet 14 toward the absorbent body 13. A plurality of recesses 22 formed by compression are formed in the compression forming area N1, and a plurality of compression rows 23 are formed, which form a pattern that is obliquely grid-like when viewed from a distance due to the arrangement of these recesses. The recesses 22 of this embodiment are inclined relative to an imaginary line P along the central axis of the wearer's body when the diaper 10 is worn. Specifically, the recesses 22 are provided with a rightward recess 22c that is inclined at a predetermined angle α in a first direction, i.e., the right direction in the figure, relative to the imaginary line P, and a leftward recess 22d that is inclined at a predetermined angle β in a second direction, i.e., the left direction in the figure. Furthermore, the recesses 22 inclined in the same direction are arranged in a row with a predetermined interval L2 between them, and form an embossed pattern that is obliquely extended in a grid-like pattern when viewed from a distance. Although not shown in the figure, the recessed portion 22 is formed by compressing the core sheet and the absorbent body 13 from the surface of the top sheet 14 .

As shown in FIG14 , the embossed pattern is not formed at either end of the absorbent body 13. Therefore, the absorbent body 13 has non-compressed portion areas (non-embossed pattern areas) N2 on both sides of the compressed portion area (embossed pattern area) N1. This is to prevent bodily fluid from leaking out of the leg opening 10L along the embossed pattern.

As shown in Figure 14, the rows aligned to the right of the recess 22c are designated as first compressed rows 23a, and the rows aligned to the left of the recess 22d are designated as second compressed rows 23b. These compressed rows 23 are arranged in a straight line, inclined relative to the imaginary line P at the same angle as the inclination of the recess 22. A plurality of first compressed rows 23a are arranged parallel to each other with intervals S1 spaced therebetween. Furthermore, a plurality of second compressed rows 23b are arranged parallel to each other with intervals S2 spaced therebetween. By arranging the plurality of first compressed rows 23a and second compressed rows 23b in this manner, an oblique grid-like embossed pattern is formed. In this embodiment, intervals S2 and S3 are set to the same value, but they may also be different values.

Moreover, it can be understood from Figure 14 that each recess 22 is of a length sufficient to form a lattice grid. Here, the length of the recess 22 is shorter than the intervals S1 and S2 mentioned above. That is, as described above, a plurality of recesses 22 are arranged at a predetermined interval L2 to form a compressed column 23, but the length of the recess and the interval of the lattice are determined in such a way that there are no recesses in the intersection area 21D of the lattice. Therefore, the right recess 22c and the left recess 22d do not overlap, forming a non-compressed area where the top sheet 14 and the absorbent body 13 are not compressed in the intersection area 21D of the oblique lattice formed by each recess 22. Similarly, in the main absorption area 24, the inner area of the grid demarcated by each recess 22, also becomes a non-compressed area where the top sheet 14 and the absorbent body 13 are not compressed.

Fig. 16 is an enlarged schematic view of the vicinity of the intersection of the compressed rows in Fig. 15 , Fig. 17 is a view showing a cross section along line XVII-XVII in Fig. 16 , and Fig. 18 is a view showing a cross section along line XVIII-XVIII in Fig. 16 .

As shown in Figures 16 and 17, the recess 22 includes a first recess 221 that forms its outer shape, and circular second recesses 222 intermittently arranged within the first recess 221 and recessed deeper than the first recess 221. As shown in Figure 16, the first recess 221 is elongated, with a length U and a width V shorter than the grid side lengths S1 and S2. Specifically, its ends are arc-shaped. Furthermore, within the first recess 221, the circular second recesses 222 are staggered at predetermined intervals relative to the longitudinal center axis. The second recesses 222 are recessed deeper in the thickness direction of the absorbent body 13 than the first recess 221.

As shown in Figure 17, within the recess 22, the second recess 222 is at its deepest point, while the first recess 221 is located slightly above the bottom of the second recess 222. If the depth to the bottom of the second recess 222, the deepest point of the recess 22, is Q11, and the depth to the bottom of the first recess 221 is Q12, then the difference (Q13)—the difference between Q11 and Q12—is approximately 3.5% to 15.0% of the depth Q11 to the bottom of the second recess 222. Furthermore, if the thickness of the uncompressed region, including the absorbent body 13 and the top sheet 14, is Q14, then the depth Q11 to the bottom of the second recess 222 is approximately 42.5% to 97.5% of the thickness Q14. Furthermore, the depth Q12 to the bottom of the first recess 221 is approximately 37.5% to 95.0% of the thickness Q14. As described above, the recessed portion 22 of the present embodiment is formed by compressing the absorber 13 extremely deeply, and has a shape having two levels of depth.

The embossing process that forms the recesses 22 involves placing an adhesive between the top sheet 14 and the absorbent core 13 and compressing the top sheet 14 and the absorbent core 13 together from the surface of the top sheet 14. The recesses 22 are formed by compressing the top sheet 14 and the absorbent core 13 together from the surface of the top sheet 14 using a predetermined pattern formed on the embossing roller. Furthermore, the second recesses 222 are smaller circles with a smaller area. Therefore, during the compression by the embossing roller, pressure is concentrated in the second recesses 222, strongly compressing the absorbent core 13 and the top sheet 14. During this compression, the pulp fibers of the absorbent core 13 and the fibers of the top sheet 14 become tightly entangled, joining them in a single, integrated state. Furthermore, the first recesses 221 also experience the same compressive force during compression, but due to their larger area, the pressure is not as concentrated as in the second recesses 222. Therefore, the bond between the absorbent core 13 and the top sheet 14 is slightly weaker than in the second recesses 222, but sufficient to form the recessed shape. In this way, by strongly compressing the absorbent core 13 within the second recess 222 and tightly bonding the absorbent core 13 to the top sheet 14, the shape of the recess 22 is maintained. For example, even when the wearer sits down and pressure is applied to the surface of the absorbent core 13 by the wearer's weight, the recess 22 does not collapse and maintains its shape. Furthermore, even if the diaper 10 is strongly stretched due to various leg movements, the top sheet 14 and the absorbent core 13 remain tightly bonded, and the recess 22 maintains its shape. Here, it is also considered that the recess 22 is formed by applying a strong compressive force to the entire recess, rather than having a two-stage structure consisting of the first recess 221 and the second recess 222. In other words, during the embossing process, it is also considered that a mold with only a flat, roughly elliptical protrusion is used to compress the interior of the roughly elliptical protrusion that matches the first recess 221, rather than using a mold that protrudes the circular protrusion that matches the second recess 222. However, it is impossible to make a position where pressure is concentrated using this model. Therefore, if a stronger pressure is not applied as a whole, it is impossible to make a position where the front sheet 14 and the absorbent body 13 are joined in a state where the fibers are entangled with each other. Therefore, the required pressing force sometimes becomes very strong, causing the top sheet 14 to rupture. In addition, if the whole is compressed with a weaker pressing force, it is impossible to form a recess 22 that can withstand the wearer's weight or various actions. In this embodiment, a position where the top sheet 14 and the absorbent body 13 are tightly joined is made by arranging a protrusion corresponding to the second recess 222 in the embossed model, and preventing the top sheet 14 from rupturing during manufacturing. In addition, depending on the strength or compression amount of the top sheet 14, this two-stage compression structure can be used instead of using a structure such as intermittently arranging dot-shaped recesses to form a compression column.

Furthermore, in FIG16 , the area indicated by the dotted line surrounding the recess 22 is a quasi-compressed area 25. Specifically, the top sheet 14 and the absorbent core 13 are strongly compressed to form the recess 22. As a result, the top sheet 14 and the absorbent core 13 around the recess 22 are stretched and compressed. Therefore, the absorbent core 13 is compressed in the quasi-compressed area 25 compared to non-compressed areas such as the intersection area 21D and the main absorbent area 24.

As shown in Figure 17, the bottom portion of the second recess 222 in the absorbent core 13 is divided into a high-density portion 13A, where the density of the absorbent core 13 is the highest. Furthermore, the uncompressed areas, such as the main absorbent region 24, constitute a low-density portion 13D, where the density of the absorbent core 13 is the lowest. Furthermore, the bottom portion of the first recess 221 is divided into a medium-density portion 13B. The quasi-compressed region 25 constitutes a density variation portion 13C, where the density gradually decreases toward the uncompressed area.

As described above, the absorbent body 13 primarily comprises SAP and pulp, and its density is primarily related to the pulp fiber density. Therefore, the high-density portion 13A is a state where the pulp is compressed and the gaps between the pulp particles are small. Meanwhile, the low-density portion 13D is a state where the gaps between the pulp particles are larger than those in the high-density portion 13A.

Furthermore, because the recesses 22 are formed by compressing and bonding the synthetic fiber topsheet 14 and the absorbent core 13, whose primary component is pulp, the bottom surface 22a of the recesses 22 can be considered thin and absorbs almost no fluid. Therefore, bodily fluid discharged into the recesses 22 is absorbed by the density variation 13C, the sidewalls of the recesses 22, and transported to the main absorbent region 24.

Secondly, in this embodiment, recesses 22 are not provided in the intersection regions 21D of the oblique lattice-shaped embossed pattern. As described above, the recesses 22 are formed by rotating and pressing an embossing cylinder, whose surface is formed with a pattern that matches the recesses 22. As shown in Figure 15, when the embossing cylinder rotates and advances in the direction indicated by arrow W, all recesses 22 arranged in a direction perpendicular to the advancing direction W of the embossing cylinder are pressed simultaneously. In this embodiment, the size of the embossing cylinder is determined so that its circumference corresponds to the longitudinal length of the absorbent core 13, but this is not limiting.

Furthermore, in this embodiment, the advancing direction W of the embossing roller is parallel to the direction of the aforementioned imaginary line P when the diaper 10 is completed. As described above, after the top sheet 14 and the absorbent body 13 are compressed together by the embossing roller, other necessary sheets are stacked, etc., and then cut to the size of the diaper 10. Since the cutting is performed along the length of the front, crotch, and back pieces of the diaper 10, by also setting the advancing direction W of the embossing roller parallel to the imaginary line P, an oblique grid-like embossed pattern can be formed that is inclined relative to the imaginary line P.

Therefore, the rightward concave portion 22c is also inclined rightward relative to the advancing direction W, and the leftward concave portion 22d is inclined leftward. Therefore, as the embossing cylinder advances in the advancing direction W, the distance between the adjacent rightward concave portion 22c and the leftward concave portion 22d gradually shortens toward the intersection region 21D.

Here, as the embossing roller, which forms the recesses 22, is pressed, the top sheet 14 is stretched by being drawn into the recesses 22. Because the adjacent rightward recesses 22c and leftward recesses 22d are pressed simultaneously, the top sheet 14 located therebetween is stretched from both the left and right sides. In other words, in Figure 15 , the pulling force indicated by arrows B is applied simultaneously from both the left and right sides, stretching the top sheet 14. As the distance between the adjacent rightward recesses 22c and leftward recesses 22d decreases, the top sheet 14 has less room to stretch due to the pulling force A, and thus, the top sheet 14 gradually becomes strongly taut.

For example, if, when making lattices of the same size, the rightward recess 22c and the leftward recess 22d are formed so as to join at the lattice corners without leaving a gap L2, then near the lattice corners, the rightward recess 22c and the leftward recess 22d are arranged close together. Furthermore, their quasi-compressed regions 25 overlap. As a result, near the corners, the absorbent body 13 itself has a higher density and is in a relatively hard state. Furthermore, the pulling force of the adjacent left and right recesses 22d and 22c causes the top sheet 14 to be strongly stretched. Consequently, the top sheet 14 in the main absorbent region 24 near the corners is in contact with the absorbent body 13 in a strongly stretched state. The SAP in the absorbent body 13 contacts the top sheet 14, causing the surface of the top sheet 14 to have an uneven feel. This is irritating to the wearer's skin and is therefore undesirable.

Therefore, in this embodiment, the top sheet 14 is prevented from being strongly stretched by not compressing the intersections of the lattice where the distance between adjacent recesses 22 is less than the predetermined distance T, i.e., the corners of the lattice. In other words, the compression of the absorbent body 13 by the recesses 22 and the joining of the absorbent body 13 and the top sheet 14 are limited to a range within the main absorbent region 24 where the top sheet 14 can maintain a slightly stretched state. This prevents the uneven texture caused by SAP and the hardening of the lattice corners.

That is, as shown in Figures 15 and 16, the shortest distance between the rightward recess 22c and the leftward recess 22d is set to T, and the recess 22 is formed only in the portion where the distance between the two is greater than T. In other words, the recess 22 is formed only in the portion where the distance between the two sides forming the grid corner is greater than T, and no recess 22 is formed in the portion less than T. Therefore, the intersection area 21D (the corner portion of the grid and its vicinity) is not compressed and thus becomes a non-compressed area, and the thickness of the absorbent body 13 becomes the same as that of the main absorption area 24. In addition, the top sheet 14 is fixed in a loose state. In the figure, the distance T is recorded in a direction perpendicular to the forward direction W, but in a direction parallel to the forward direction W, problems caused by the hardening of the corner portion may also occur, so it is preferred to form each recess 22 by a distance greater than a fixed distance. In this embodiment, since the lengths of the rightward recess 22c and the leftward recess 22d are set equal and the intervals L2 therebetween are also set equal, the recesses 22 are also formed at a distance T or more in a direction parallel to the advancing direction W.

In other words, when determining the embossing pattern, the arrangement interval of each recess 22 is determined so that the distance between adjacent recesses becomes greater than T in a direction parallel to the diagonal line of the quadrilateral (grid) divided by the first compressed row 23a and the second compressed row 23b.

In addition, as described above, the pulling force A acts strongly in the direction perpendicular to the forward direction W of the embossing roller. Therefore, for the diagonal line parallel to the forward direction W of the embossing roller, even if the distance between adjacent recesses is slightly shorter than T, it can be said that its influence is small.

For example, in this embodiment, T is approximately 7 mm when the thickness of the absorbent body 13 is 8 mm and the depth Q12 of the first recess 221 is 6 mm. T also varies depending on the relationship between the amount of SAP and the amount of pulp fiber in the absorbent body 13, or the thickness of the top sheet 14. In the present invention, it is important to avoid forming the embossed pattern in areas where the spacing between adjacent recesses is narrowed when using an embossed pattern having an oblique component, such as an oblique lattice pattern.

As described above, in this embodiment, the shortest distance between adjacent recesses 22 is no less than T. Specifically, by employing an embossed pattern in which recesses 22 are spaced at least a distance apart (T), i.e., by not embossing near the intersections of the latticework, the skin-contacting surface is prevented from feeling hard. Furthermore, because the latticework corners are soft, just like the main absorbent regions 24, even with an oblique latticework embossed pattern, the latticework corners do not feel hard or sharp, providing a soft feel to the wearer's skin. Therefore, by omitting recesses 22 in the intersection region 21D between the first and second compressed rows 23a, 23b, the latticework corners do not feel hard or sharp. Furthermore, the thickness and height of the absorbent core 13 in the intersection region 21D are the same as those in the main absorbent regions 24. Therefore, even with an oblique latticework embossed pattern, the skin-contacting surface of the diaper 10 provides a soft feel to the wearer's skin, and the latticework corners do not irritate the skin.

In addition, in this embodiment, although the embossing process is described using an embossing roller, the present invention is not limited to this method. A plate-shaped embossing plate that matches the size of the diaper 10 may be used to press and emboss the diaper 10 in units of the size.

Next, details of an embodiment of an embossed pattern formed by embossing will be described.

As shown in Figure 15, the embossed pattern of this embodiment is composed of rightward concave portions 22c spaced apart by a distance L2 in the longitudinal direction, forming first compressed rows 23a. Leftward concave portions 22d spaced apart by a distance L2 in the longitudinal direction, forming second compressed rows 23b. The first compressed rows 23a are arranged in parallel rows at a distance S1, while the second compressed rows 23b are arranged in parallel rows at a distance S2. These first compressed rows 23a and second compressed rows 23b form an embossed pattern that, when viewed from a distance, resembles a diagonal grid, as shown in the figure.

In this embodiment, the length S1 and S2 of one side of the grid are equal and are 27.0 mm. The spacing between the grids is preferably greater than 13.0 mm and less than 54.0 mm. In addition, the length U of the recess 22 in the longitudinal direction is about 55% to about 85% of the length S1 and S2 of one side of the grid. In this embodiment, the length U is 19.0 mm. In addition, the width V of the recess 22 is 3.0 mm. The width V is preferably greater than 2.0 mm and less than 4.0 mm. In addition, the spacing L2 between the recesses 22 is 8.8 mm. The spacing L2 is preferably greater than 4.0 mm and less than 12.0 mm. By setting this relationship, the portion where the distance T between adjacent recesses 22 is less than 6.0 mm becomes a recess-free state.

In this embodiment, the thickness of the absorbent body 13 and top sheet 14 before embossing is 8.0 mm. As shown in FIG17 , the depth Q11 of the deepest portion of the recess 22 is 7.8 mm. The depth Q12 of the next deepest portion is 7.5 mm. Furthermore, the thickness Q14 of the uncompressed region is 8.0 mm.

The thickness of the absorbent body 13 and topsheet 14 before embossing is preferably 5.0 mm to 20.0 mm. Furthermore, the maximum depth Q11 of the portion compressed by the recesses 22 is preferably 3.0 mm to 8.0 mm. Furthermore, the difference Q13 between the maximum depth Q11 and the next deepest portion is preferably 0.1 mm to 0.5 mm. Furthermore, the thickness Q14 of the uncompressed region is preferably 5.0 mm to 20.0 mm.

By forming the recesses 22 at such depths and intervals, the grooves are maintained even when weight is applied, and the skin-contacting surface of the crotch portion of the diaper 10 maintains a soft feel. Therefore, the oblique grid-like embossed pattern prevents deformation of the diaper 10, such as twisting, caused by various leg movements, and maintains a soft feel to the skin, minimizing skin irritation.

Furthermore, in this embodiment, the outer shape of the recesses 22 is defined by the elongated, generally elliptical first recesses 221. However, the present invention is not limited thereto. Multiple recesses, such as those in the shape of a point or a parallelogram, may be intermittently arranged to form a compressed array in the shape of an oblique grid. Specifically, by spacing the recesses so that the corners (intersections) of the oblique grid squares are wider than the sides of the squares, the same effects as those of this embodiment can be achieved. In this case, the recesses are also arranged so that the distance between adjacent recesses parallel to the diagonal lines of the grid squares is greater than T.

In this embodiment, a single recess 22 forms one side of the grid. However, the longitudinal length of the recess 22 may be shortened, so that two or more recesses 22 form one side of the grid. Furthermore, the second recesses 222 within the first recess 221 are arranged in a staggered pattern on the outer sides in the width direction, but the present invention is not limited to this arrangement; any other configuration is also possible, such as a configuration in which the second recesses 222 are arranged in a row in the center. Furthermore, the shape of the second recesses 222 is not limited to that shown in this embodiment; various shapes such as a quadrilateral, an ellipse, or a triangle may be employed.

The disposable diaper 10 of this embodiment can be used for both adults and children. While this embodiment illustrates an unfolded diaper 10 (so-called sheet-type diaper), it can also be applied to pants-type diapers. Furthermore, the absorbent article of the present invention is not limited to diapers but can be applied to all other absorbent articles, such as absorbent pads. For example, as shown in FIG14 , the structure of the absorbent body 13 and the top sheet 14 indicates that the present invention can also be applied to articles that have the same functions and effects as diapers, such as absorbent pads.

Next, the relationship between the formation method of the recessed portion and the thickness of the intersection region will be described. The recessed portion 22 is formed by, for example, compressing the topsheet 14 and the absorber 13 from the topsheet 14 side of the disposable diaper 10 using a mold.

FIG19 illustrates a method for forming recesses when the distance between adjacent molds is wide. When the distance between adjacent molds 191, i.e., the distance Q4 between recesses 22 across intersection region 21D1, is wide, the thickness Q19 of intersection region 21D1 remains unchanged because little force is applied from either side of the surface of intersection region 21D1 between recesses 22 compressed by mold 191. Consequently, thickness Q19 of intersection region 21D1 is equal to thickness Q14 of main absorbent region 24.

Figure 20 illustrates a method for forming recesses when the distance between adjacent molds is narrow. When the distance between adjacent molds 201, i.e., the distance Q4 between recesses 22 across intersection region 21D2, is narrow, the topsheet 14 and absorber 13 on either side of intersection region 21D2 are compressed, and the topsheet 14 and absorber 13 in intersection region 21D2 are pressed inward. Thus, a recess is formed in intersection region 21D2, located between recesses 22 compressed by mold 201, despite not being directly compressed. Consequently, the thickness Q20 of intersection region 21D2 is thinner than the thickness Q14 of main absorbent region 24.

2 shows a standing state after wearing the diaper 10, but the present invention is not limited to the case of standing walking, but also has an overall effect on the forward and backward movement of the legs such as turning over or crawling of the baby.

The structure of the diaper subject to the present invention is not limited to the unfolded type described above, and any structure may be employed as long as the diaper comprises the absorbent article structure defined in the claims. For example, the present invention can also be applied to conventional shorts-type disposable diapers or urine leakage pads.

Furthermore, the present invention is not limited to diapers for infants and can also be applied to various absorbent articles such as diapers for adults and urine leakage pads.

The absorbent article of the present invention can also be an absorbent article having a liquid-permeable front sheet, a liquid-impermeable back sheet, and an absorbent body arranged between the front sheet and the back sheet, and the absorbent article has a flow channel forming area having multiple flow channels extending on the front sheet, and the flow channel has multiple recesses formed by compressing the front sheet and the absorbent body.

In the absorbent article of the present invention, the recessed portions may be intermittently arranged at the bottom of the flow channel.

In the absorbent article of the present invention, the recessed portion may not exist in an intersection region of the plurality of flow channels.

In the absorbent article of the present invention, the compression density of the topsheet and the absorbent body in the intersection area of the plurality of flow paths may be lower than the compression density of the topsheet and the absorbent body at the bottom of the recess.

In the absorbent article of the present invention, the flow channel may extend intermittently or continuously from one end to the other end of the flow channel forming region.

In the absorbent article of the present invention, the flow path forming region may not reach the edge of the absorbent body.

In the absorbent article of the present invention, the interval between adjacent recessed portions may be 10 mm to 70 mm.

The absorbent article of the present invention may be a disposable diaper having a size such that the absorbent body extends over the front piece, crotch, and back piece.

The absorbent article of the present invention can also be an absorbent article having a liquid-permeable front sheet, a liquid-impermeable back sheet, and an absorbent body arranged between the front sheet and the back sheet and containing pulp fibers and SAP, and the front sheet side of the absorbent article includes a flat portion and a plurality of recessed portions that integrally join the front sheet and the absorbent body, the plurality of recessed portions divide the flat portion into a plurality of flat partitions to form a plurality of flow channels for liquid circulation, and the area of the divided flat partitions is greater than 0.5 ^cm2 .

In the absorbent article of the present invention, the liquid permeability of the flow channel may be lower than the liquid permeability of the flat portion.

In the absorbent article of the present invention, the SAP amount per unit area of the absorbent body may be 100 g/cm ² or more.

In the absorbent article of the present invention, the width of the flow channel may be 1.0 mm or more and 6.0 mm or less.

In the absorbent article of the present invention, the area of the flat section may be 0.5 cm ² or more and 50.0 cm ² or less.

In the absorbent article of the present invention, the plurality of flow channels may extend intermittently or continuously in a lattice pattern.

In the absorbent article of the present invention, the flow channel may be formed by compressing the topsheet and the absorbent core together.

In the absorbent article of the present invention, the absorbent article may be a disposable diaper having a size extending over the front piece, crotch, and back piece.

The absorbent article of the present invention can also be an absorbent article, having a liquid-permeable front sheet, a liquid-impermeable back sheet, and an absorbent body arranged between the front sheet and the back sheet, and having a compression portion forming area with multiple compression columns, wherein the compression columns are arranged with multiple recessed portions formed by compressing the front sheet and the absorbent body, and the compression columns have: a first compression column, which extends obliquely to one side relative to an imaginary line extending from the wearer's abdomen through the crotch to the back when the absorbent article is worn; and a second compression column, which extends obliquely to the other side; the compression portion forming area arranges multiple of the first compression columns and the second compression columns in a grid shape, and there is no recessed portion at the intersection of the first compression column and the second compression column.

In the absorbent article of the present invention, the recessed portion may integrally join the topsheet and the absorbent core.

In the absorbent article of the present invention, the non-compressed regions of the absorbent body may all have the same thickness, and the intersection portion may be the non-compressed region.

In the absorbent article of the present invention, a distance between adjacent recessed portions in a direction parallel to a diagonal line of a quadrilateral defined by the first compressed rows and the second compressed rows may be 6 mm or more.

In the absorbent article of the present invention, the intervals between the plurality of first compressed rows and the intervals between the plurality of second compressed rows may be 13 mm or more and 54 mm or less.

In the absorbent article of the present invention, the recessed portion may include a first recessed portion and a second recessed portion further recessed within the first recessed portion.

The absorbent article of the present invention may be a disposable diaper having a size such that the absorbent body extends over the front piece, crotch, and back piece.

[Explanation of Symbols]

10. Disposable diapers

10A fastening strap

10B front patch sheet

10F Front Body Area

10R back body area

10C Crotch area

10W waist opening

10L leg opening

10D elastic sheet

11 Cover sheet

11A, 13A notch

11B inner cover sheet

11C External cover

12 bottom sheet (back sheet)

13 Absorber

13S hydrophilic sheet

13T liquid diffusion sheet

14 Top sheet (front sheet)

15, 19 rubber cord

18 side panels

21 runner

21a First flow channel

21b Second flow channel

21D, 21D1, 21D2 intersection area (intersection of flow channels)

22 recess

22a Bottom surface of recess

22b The portion other than the concave portion of the flow channel (recessed space)

22c Rightward concave portion (concave portion inclined toward the first direction)

22d Leftward concave portion (concave portion inclined toward the second direction)

221 First recess

222 Second concave portion (the portion forming the deepest bottom of the concave portion)

23 Compressed Columns

23a First compressed column

23b Second compressed column

24, 24A, 24B Main absorption area (flat partition)

25 Quasi-compression region

191, 201 mold

Q1 Width of flow channel

Q2 Diameter of recess

Q3 Arrangement interval of recesses 22

Q4 The distance between the centers of adjacent recesses in the intersection area

Q5 Depth of recess 22

Q11 Maximum depth of the concave portion to the bottom of the second concave portion

Q12 Depth to the bottom of the first recess

Q13 Difference in depth between the first concave portion and the second concave portion

Q14 Thickness of the non-compressed area (main absorption area)

Q19, Q20: The distance between adjacent recesses

L1 diagonal of 1 square

L2 Anterior-posterior spacing between adjacent concave portions of the compression row

S1 Formation interval of multiple first compression trains

S2: Interval between the formation of multiple second compression trains

T The shortest distance between adjacent recesses

Length of the U concave portion in the longitudinal direction

V The length (width) of the concave part in the short side direction

Claims (6)

1. An absorbent article, characterized by comprising: a liquid-permeable front sheet, a liquid-impermeable back sheet, and an absorbent disposed between the front sheet and the back sheet. Multiple compression columns extend from the front sheet side, and the compression columns are arranged with multiple flow channels. Each flow channel includes a recess formed by compressing the front sheet and the absorbent, and a recessed space formed by pressing down the absorbent near the recess through the compression. The multiple compressed columns form intersecting regions. The absorber is located between the bottom of the recess and the back sheet, and The compressive density of the front sheet and the absorber in the entire area of the intersection region is lower than that of the front sheet and the absorber in the recess. 2. The absorbent article according to claim 1, wherein the thickness of the cross region is the same as the thickness of the main absorbent region surrounded by the plurality of compression columns. 3. The absorbent article according to claim 1, wherein the thickness of the intersecting region is thinner than the thickness of the main absorbent region surrounded by the plurality of compression columns. 4. The absorbent article according to claim 1, characterized in that: the area of the main absorbent region surrounded by the plurality of compression columns is 0.5 ^cm² or more. 5. The absorbent article according to claim 1, characterized in that: the plurality of compressed columns extend in a lattice pattern intermittently or continuously. 6. The absorbent article according to claim 1, wherein the recess comprises a first recess and a second recess formed by further recessing within the first recess.