JP7023045B2 - Absorbent article - Google Patents

Description

The present disclosure relates to absorbent articles, in particular to absorbent articles such as disposable diapers, incontinence pads, menstrual napkins and the like.

Absorbent articles such as sanitary napkins and disposable diapers are required to have excellent absorbency and rewetability. For example, in Patent Document 1, protruding absorption portions scattered in the plane direction discontinuously on the non-skin contact surface side of the absorber, and recessed in the thickness direction from the non-skin contact surface side arranged between them. It has a liquid-permeable structure formed by groove-shaped recesses and has a specific density, which is intended to provide the wearer with an excellent dry feeling. In Patent Document 2, a plurality of penetrating or non-penetrating slits are formed in the absorbent core extending in the longitudinal direction, and a wide portion having a wide slit width is formed at a position different from the bi-folded or tri-folded position of the product. By providing the above, it is taught to control the bending in the longitudinal direction and the width direction of the absorbent core so as not to deteriorate the performance of the absorbent core.

JP2012-130365 (Patent No. 5581192) Japanese Patent Application Laid-Open No. 2012-157380 (Patent No. 5783734)

In Patent Document 1, protruding absorption portions having high absorbency are scattered discontinuously, and the periphery thereof is surrounded by groove-shaped recesses which have liquid permeability but do not have active liquid transport capacity. In Patent Document 1, although the flexibility of the absorber is increased by the groove-shaped recess, the liquid absorption due to the capillary phenomenon is limited to the periphery of each protruding absorption portion, and the area used by the absorber is not widened. Is prone to peaking out. In Patent Document 2, a wide portion is provided in the slit of the absorbent core, and even if there is a crease, the fit due to the slit in the longitudinal direction is well developed, and leakage prevention is obtained through the improvement of the fit. However, in Patent Document 2, although the slit portion improves the fit, it only prevents the absorption performance from being impaired and does not improve the absorption function.

Therefore, it is an object of the present disclosure to provide an absorbent article having excellent absorbency and rewetability.

The non-limiting aspects of the present disclosure that solve the above problems are as follows.
<Aspect 1> An absorbent article comprising an absorption core having a longitudinal direction, a lateral direction and a thickness direction, wherein the absorption core has one surface and the other surface; the absorption core is The one surface has a plurality of ridges extending in the longitudinal direction and a plurality of grooves extending in the longitudinal direction, and the ridges and the grooves are alternately present in the lateral direction. The ridges are wider than the narrow portions between the narrow portions and the narrow portions that are intermittently narrowed in the lateral direction along the longitudinal direction. It has a plurality of wide portions, and the constriction ratio, which is the ratio of the minimum dimension of the narrow portion in the lateral direction to the maximum dimension of the wide portion in the lateral direction, is 10% or more and 50% or less. An absorbent article characterized by being present.

In the absorbent article according to aspect 1, the excreted liquid, particularly urine, is transported far in the longitudinal direction of the absorption core through the groove and absorbed in a wider area, so that the absorption performance of the entire absorption core is achieved. (Penetration rate) is improved. Since the liquid is transported from the excretion site, there is little decrease in the absorption capacity of the absorption core near the excretion site. In addition, since it has excellent permeability at the excretion site, there is little rewetting. In the absorption core using the liquid passage structure of the absorption core as described above, increasing the number of grooves increases the area of the groove wall surface of the absorption core, but surprisingly, rather than simply increasing the number of grooves in the longitudinal direction. It has been found that when the ridges between the grooves are made to have a liquid-passing structure having a specific constricted shape, the absorption performance and the re-wetting property are more excellent than those of the conventional liquid-passing structure. Further, in the case of the lattice-shaped liquid passage structure, since the ridges are not continuous in the longitudinal direction, the liquid transport capacity in the longitudinal direction is low, and the absorption core cannot be used in a wide area. When the ridges are provided with a constriction, the ridges are continuous in the longitudinal direction, but when the amount of discharged liquid is large, it is possible to move from the groove side with a large amount of liquid to the groove side with a small amount of liquid. It is considered that the absorption performance of the absorption core can be improved by diffusing in the longitudinal direction using the entire width direction of the absorption core.

<Aspect 2> The groove portion includes a plurality of main groove portions extending in the longitudinal direction and a plurality of slave groove portions extending in the lateral direction from the main groove portion, and the main groove portions adjacent to each other in the lateral direction. The sub-grooves extending from each of the grooves in the lateral direction face each other, and the narrow portion of the ridge is formed between the facing sub-grooves, and the narrow portion of the ridge is formed. The absorbent article according to aspect 1, wherein the portion other than the portion is the wide portion.

<Aspect 3> The groove portion has a zigzag shape or a corrugation in the longitudinal direction, and the groove portions adjacent to each other in the lateral direction have zigzag shape or corrugated protrusions approaching each other and facing each other. The absorbent article according to aspect 1, wherein the narrow portion of the ridge is formed between the protrusions, and a portion of the ridge other than the narrow portion is the wide portion.

Aspects 2 and 3 are absorbent articles that specifically realize the predetermined constricted structure of Aspect 1.

<Aspect 4> Any one of aspects 1 to 3, wherein the dimension of each of the wide portions in the longitudinal direction is 1.0 to 2.0 times the average dimension of each of the wide portions in the lateral direction. The absorbent article described in the section. In the absorbent article according to the fourth aspect, when the dimension in the longitudinal direction of the wide portion is 1.0 times or more the dimension in the lateral direction, the transport of the liquid through the groove portion can be increased. When it is 0 times or less, the area of the ridge portion in contact with the groove portion becomes large, and the absorption performance can be improved.

<Aspect 5> The absorbent article according to any one of aspects 1 to 4, wherein the groove is three or more. In the absorbent article according to the fifth aspect, when the number of main grooves is 3 or more, more preferably 4 or more, it is preferable to transport a larger amount of liquid in the longitudinal direction of the absorbing core.

<Aspect 6> The absorbent article according to any one of aspects 1 to 5, wherein the width of the groove is 1 to 3 times the thickness of the absorption core. In the absorbent article according to aspect 6, the width of the groove is 1 to 3 times the thickness of the absorption core, so that the liquid is efficiently transported through the groove.

The disclosure further includes the following aspects:
<Aspect 7> The absorbent article according to any one of aspects 1 to 6, wherein the wide portion has an average dimension of 10 to 30 mm, more preferably 12 to 25 mm, and further 14 to 22 mm in the lateral direction. .. The absorbent article according to aspect 7 can be excellent in the ability of the absorbing core to absorb and retain the liquid.

<Aspect 8> The absorbent article according to any one of aspects 1 to 7, wherein the wide portion has an average dimension of 12 to 30 mm, more preferably 15 to 25 mm, and further 18 to 22 mm in the longitudinal direction. In the absorbent article according to aspect 8, the liquid transport capacity of the absorbent core can be excellent.

According to the present disclosure, it is possible to provide an absorbent article having improved absorption performance and excellent rewetability as compared with the conventional case. In addition, the absorbent article of the present disclosure is also excellent in fit.

FIG. 1 is a plan view of the absorbent article 1 according to the first embodiment. FIG. 2 is a plan view of the absorber 7 of the absorbent article 1 according to the first embodiment. FIG. 3 is a plan view of the absorption core 9 of the absorbent article 1 according to the first embodiment. FIG. 4 is a perspective view showing a part of the absorption core 9 of the absorbent article 1 according to the first embodiment. 5 is a cross-sectional view showing a part of the absorption core 9 in the line segment VV in FIGS. 5 and 2. FIG. 6 is a cross-sectional view showing a part of the absorption core 9 in the line segment VI-VI in FIG. 7 (a) and 7 (b) are partial plan views of an absorption core 9 corresponding to FIG. 3 for explaining a state in which the absorbent article 1 according to the first embodiment absorbs a liquid. FIG. 8 is a plan view of the absorber 7 of the absorbent article 1 according to the second embodiment. FIG. 9 is an enlarged plan view of a part of the absorption core 9 of FIG. FIG. 10 is a cross-sectional view of the absorption core 9 of the third embodiment corresponding to FIG. FIG. 11 is a cross-sectional view of the absorption core 9 of the third embodiment corresponding to FIG.

The absorbent articles of the present disclosure will be described in detail below.

[First Embodiment]
1 to 7 are diagrams for explaining an absorbent article 1 according to one of the embodiments of the present disclosure (first embodiment), specifically, a disposable diaper. FIG. 1 is a plan view of the absorbent article 1 according to the first embodiment. FIG. 2 is a plan view of the absorber 7 of the absorbent article 1 according to the first and third embodiments. FIG. 3 is a plan view of the absorption core 9 of the absorbent article 1 according to the first embodiment. FIG. 4 is a perspective view showing a part of the absorption core 9 of the absorbent article 1 according to the first embodiment.

As shown in FIG. 1, the absorbent article 1 shown in the first embodiment is between the liquid permeable sheet 3, the liquid permeable sheet 5, and the liquid permeable sheet 3 and the liquid permeable sheet 5. Includes the absorber 7 and. In the first embodiment, as shown in FIG. 1, the absorbent article 1 is fixed to fix the pair of leak-proof walls 101 including the elastic member 103 and the leak-proof wall 101 to the liquid-permeable sheet 3. It has a portion 105, an elastic member 107, a tape fastener 109, and the like, but since these are known in the art, description thereof will be omitted.

As shown in FIG. 2, the absorber 7 has an absorption core 9 (see FIG. 3) having a longitudinal direction Y and a lateral direction X, a skin facing surface 15 and a non-skin facing surface (clothing side surface) 17. , A core wrap 11 (see FIGS. 5 and 6) arranged on the skin facing surface 15 side and the non-skin facing surface 17 side of the absorption core 9. Further, a diffusion sheet (not shown) can be provided between the skin facing surface 15 of the absorption core 9 and the core wrap 11 arranged on the skin facing surface 15 side. In the first embodiment, the absorbent article 1 has the same longitudinal direction Y and lateral direction X as the absorber 7.

As shown in FIGS. 3 to 4, one of the skin facing surface 15 and the non-skin facing surface 17, for example, the non-skin facing surface 17 is recessed in the thickness direction of the absorption core 9 and extends in the longitudinal direction Y. A groove 18 is provided. The groove portion 18 includes a plurality of main groove portions 19 extending in the longitudinal direction Y. In a strict sense, the main groove portion 19 does not need to extend in the longitudinal axis direction, and may be substantially in the longitudinal axis direction of the absorption core 9, and may be, for example, within ± 30 degrees from the longitudinal axis direction. Further, the main groove portion 19 does not have to be linear in a strict sense, and it is sufficient that the main groove portion 19 extends in the longitudinal direction Y as a whole even if the line is swayed to some extent.

As shown in FIGS. 3 to 4, the groove portion 18 includes a plurality of sub-groove portions 21 that are recessed in the thickness direction of the absorption core 9 and extend in the lateral direction X from the non-skin facing surface 17. As shown in FIGS. 2 to 4, each of the slave groove portions 21 extends in an intersecting direction with each of the plurality of main groove portions 19 as a base end and has an end. In a strict sense, the slave groove portion 21 does not need to extend in the short axis direction, and may be substantially in the short axis direction of the absorption core 9, for example, within ± 30 degrees from the short axis direction. .. The slave groove portions 21 are usually formed on both sides of each of the main groove portions 19, but in the main groove portions 19 at both ends on the outermost side of the absorption core 9, the slave groove portions 21 outside the main groove portions 19 are omitted. Is also possible.

The absorption core 9 has a ridge portion 20 as a portion extending in the longitudinal direction Y between the main groove portions 19 extending in the longitudinal direction Y. The ridges 20 extending in the longitudinal direction Y and the main groove 19 alternately exist in the lateral direction X. The ridge portion 20 forms a narrow portion 20-2 of the ridge portion 20 between the ends of the opposing groove portions 21 extending from the main groove portion 19 on both sides of the ridge portion 20 toward the ridge portion 20 and has a width. The remaining portion of the narrow portion 20-2 forms a wide portion 20-1 sandwiched between the main groove portions 19. It should be noted that the secondary groove portions 21 extending from each of the main groove portions 19 that are in contact with each of the ridges 20 on both sides toward the inside of the ridges 20 and forming a narrow portion 20-2 between them need to face each other. The secondary groove portions 21 on both sides of the main groove portion 19 do not need to extend from the same position of the main groove portion 19 to both sides.

FIG. 4 is a perspective view showing a part of the absorption core 9 as viewed from the non-skin surface side. There are a plurality of main groove portions 19 extending in the longitudinal direction Y of the absorption core 9 arranged side by side in the lateral direction X, and between the main groove portions 19 the ridge portions 20 extending in the longitudinal direction Y (wide portion 20-1 and narrow portion). 20-2). From the main groove portion 19, intermittent follow-groove portions 21 extend to both sides in the lateral direction X. The slave groove portions 21 extending from the adjacent main groove portions 19 toward the ridges 20 between them face each other, and the narrow portions 20-2 of the ridge portions 20 are between the slave groove portions 21. Is forming. The wide portions 20-1 of the ridges 20 adjacent to each other in the longitudinal direction are continuous as the ridges 20 via the narrow portions 20-2 in between.

FIG. 5 is a cross-sectional view taken along the line segment VV in FIG. 2, and represents a part of a cross section of the absorption core 9 cut by a line segment in the lateral direction X in the wide portion 20-1. FIG. 6 is a cross-sectional view of the line segment VI-VI in FIG. 2, and shows a part of a cross section of the absorption core 9 cut by a line segment in the lateral direction X in the narrow portion 20-2. In FIG. 5, there is a main groove portion 19 between the wide portions 20-1, and in FIG. 6, the narrow portion 20-2 is in contact with the slave groove portions 21 extending on both sides of the main groove portion 19. FIG. 5 shows the width W ₁ of the wide portion 20-1 and the width W _m of the main groove portion 19 (both are dimensions in the lateral direction X). FIG. 6 shows the width W ₁ of the wide portion 20-1, the width W _m of the main groove portion 19, the length L _s of the slave groove portion 21, and the width W ₂ of the narrow portion 20-2 (all are short). It is the dimension of the hand direction X). In the present disclosure and the following, the dimensions of various members are generally average values when the dimensions are not specified as the maximum value, the minimum value, etc. in the context.

In the first embodiment, the minimum width dimension of the narrow portion 20-2 (dimension in the lateral direction X; the same as the width of the narrow portion 20-2 in this example) W ₂ is the maximum width of the wide portion 20-1. It has _a predetermined relationship with the dimension (dimension in the lateral direction X; the same as the width of the wide portion 20-1 in this example) W1. Specifically, the width of the narrow portion 20-2 is 50% or less and 10% or more of the width of the wide portion 20-1, preferably less than 50% and 10% or more, 40% or less and 15% or more, and 40%. The dimensions are less than 15% or more, more preferably 36% or less and 20% or more. When the width of the narrow portion 20-2 is within this range, the liquid can be diffused in a well-balanced manner in both the longitudinal direction and the lateral direction, and the absorption performance of the absorption core after repeated absorption can be excellent. Further, although not limited, the width (dimension of X in the lateral direction) W ₂ of the narrow portion 20-2 is preferably 2 to 15 mm, more preferably 2 mm or more and less than 10 mm, and 4 to 8 mm. Is preferable. In the present disclosure, the minimum and maximum values of the width of the ridges are contoured with smooth lines along the outer shape of the ridges in a plan view in order to avoid the influence of unnecessarily minute dimensional changes. It is possible to draw and adopt the value of the part where the dimension is the minimum and the maximum. In this example, the minimum width dimension of the narrow portion 20-2 and the maximum width dimension of the wide portion 20-1 are the narrow portion. The width (average value) of 20-2 and the width (average value) of the wide portion 20-1 can be used.

The length (dimension of Y in the longitudinal direction) L ₁ of the wide portion 20-1 of the ridge 20 may be 0.8 times or more the width (dimension of X in the lateral direction) W ₁ of the wide portion 20-1. It is preferable, more preferably 1.0 times or more, still more preferably 1.05 times or more, and even more preferably 1.1 times or more. It may be 1.2 times or more. It is preferably 2.0 times or less, 1.5 times or less, and 1.3 times or less. Although not limited, the length L ₁ of the wide portion 20-1 is preferably 12 to 30 mm, more preferably 15 to 25 mm and 18 to 22 mm. The width W ₁ of the wide portion 20-1 is preferably 10 to 30 mm, more preferably 12 to 25 mm and 14 to 22 mm.

The width of the lateral side X of the entire region where the plurality of main groove portions 19 and the plurality of slave groove portions 21 are formed in the absorption core 9 (the slave groove portion 21 or the main groove portion 19 closest to the end in the lateral direction of the absorption core 9). The _Wg (distance between the ends) is preferably 50% or more, preferably 60% or more, 70% or more, and further 80% or more, 85 of the total width _W0 of the absorption core 9. % Or more is possible. It is preferable to utilize the effect of providing the main groove portion 19 and the sub-groove portion 21 in as much area as possible of the absorption core 9.

The dimension of the main groove 19 in the longitudinal direction Y is preferably twice or more, more preferably 2.5 times or more the total width of the absorption core 9 (dimension X in the lateral direction) W ₀ , and is preferably 2.5 times or more in the longitudinal direction of the absorption core 9. It may penetrate the entire length of Y. This is to effectively utilize the absorption performance of the absorption core 9 by the main groove portion 19 in the longitudinal direction.

The number of main groove portions 19 is preferably selected so that the width (X and dimension in the lateral direction) of the wide portion 20-1 of the ridge portion 20 is 10 to 30 mm, preferably 14 to 25 mm. In order to efficiently transport the liquid in the longitudinal direction of the absorption core, it is preferable that the number of main grooves is three or more, particularly four or more. 4 to 8 and 4 to 6 are preferable numbers.

The width of the main groove portion 19 (dimension of X in the lateral direction) W _m and the width of the slave groove portion 21 (dimension of Y in the longitudinal direction) W _s are 0.5 to 5 times the thickness of the absorption core 9, and further 1 to 1. It is preferably 3 times and 1.5 to 2.5 times. The width (dimension of X in the lateral direction) W _m of the main groove portion 19 and the width (dimension of Y in the longitudinal direction) W _s of the slave groove portion 21 are, for example, 2 to 10 mm, depending on the thickness of the absorption core 9. It is preferably 2 to 8 mm, more preferably 3 to 6 mm. The width (dimension of Y in the longitudinal direction) W _s of the slave groove portion 21 is preferably 0.5 to 2 times, more preferably 0.7 to 1.3 times, the width W _m of the main groove portion 19. Within this range, there is a good balance between the ease with which the liquid flows from the main groove portion 19 to the slave groove portion 21 and the flow of the liquid in the direction of the main groove portion 19.

The width (dimension of X in the lateral direction) W ₁ of the wide portion 20-1 of the ridge portion 20 may be 2.5 to 10 times, further 3.5 to 7 times, the width W _m of the main groove portion 19. preferable. Within this range, the liquid absorption performance can be excellent.

When the width of the slave groove portion 21 is Ws, the total length of the main groove portion 19 is Lm, and the number of the slave groove portions 21 provided on one side of one main groove portion 19 is n, 0.1 Lm / n ≦ Ws ≦ 0. It is preferable to satisfy .4 Lm / n, more preferably 0.2 Lm / n ≦ Ws ≦ 0.4 Lm / n. It is preferable to satisfy 0.1 Lm / n ≦ Ws ≦ 0.2 Lm / n. If the width of the slave groove is provided within a predetermined range, the liquid is easily absorbed into the ridges by the capillary phenomenon through the end of the slave groove, so that the absorbency of the absorption core ( In particular, it becomes easy to improve the absorption rate) and the suppression of liquid return.

Further, it is preferable that the end of the slave groove portion is present at 0.05 to 1 piece / cm2, more preferably 0.1 to 0.5 pieces / cm2 per unit area of the absorber. When the number of the ends of the slave groove portions is provided within a predetermined range, it becomes easy to improve the suppression of liquid return of the absorber for the same reason as described above.

The depth of the recess in the thickness direction of the main groove portion 19 and the slave groove portion 21 is preferably 0.2 to 1.0 times the thickness of the absorption core 9, but the dimension is 0.3 to 0.7 times. Is more preferable.

In the present specification, the thickness (mm) of the absorption core is measured as follows. Prepare FS-60DS [measurement surface 44 mm (diameter), measurement pressure 3 g / cm ² ] manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd. and absorb under standard conditions (temperature 23 ± 2 ° C, relative humidity 50 ± 5%). Five different parts of the core are pressurized, the thickness of each part after 10 seconds of pressurization is measured, and the average value of the five measured values is taken as the thickness of the absorber. The depth of the groove portion of the absorption core can be obtained by subtracting the thickness (average value) of the absorption core in the groove portion from the thickness (average value) of the absorption core in the ridge portion.

Further, in the present specification, various dimensions of the members of the absorbent article in a plan view can be measured with a ruler, but the average value is calculated from the measured values at any five points.

In the first embodiment, the main groove portion and the sub-groove portion have the above-mentioned shape and dimensions, but a part of the sub-groove portion may be different from the above-mentioned shape and dimensions. It is desirable that the ratio of the secondary groove portion different from the above shape and dimensions is zero, but it is acceptable if the area in the plan view is 30% or less, further 20% or less, and 10% or less of the total area of the secondary groove. May be done.

In the present embodiment, the absorbent core 9 includes a core wrap 11 made of a hydrophilic non-woven fabric, for example, a hydrophilic spunbonded non-woven fabric, which covers the skin facing surface and the non-skin facing surface, and as shown in FIGS. 5 and 6. On the non-skin facing surface, the core wrap 11 does not abut on the bottom of the main groove 19. However, in the absorbent article of the present disclosure, the core wrap may be arranged so as to be convex in the main groove portion on the non-skin facing surface. In such a case, the diffusivity of the body fluid in the main groove can be improved. Further, in the absorbent article of the present disclosure, the core wrap may be in contact with the main groove corresponding portion on the non-skin facing surface, or may be partially or continuously joined to the main groove corresponding portion by a squeezed portion or the like. You may. As the core wrap, a tissue may be used in addition to the hydrophilic non-woven fabric.

It will be described using the first embodiment that the absorbent article of the present disclosure is excellent in liquid absorption performance and rewetability, and is excellent in wearing feeling.

When the liquid 31 that has reached the absorption core 9 is present on the skin facing surface 15, it permeates the bottoms of the main groove portion 19 and the sub-groove portion 21. The liquid 31 that has reached the main groove portion 19 and the slave groove portion 21 is diffused in the longitudinal direction Y of the absorption core 9 through the main groove portion 19 and is also diffused in the longitudinal direction Y of the absorption core 9 and is connected to the main groove portion 19 and passes through the vacant slave groove portion 21 to pass through the absorption core 9 It is also diffused in the lateral direction X of the above, and penetrates into the inside of the absorption core 9 through the groove wall surface in contact with the main groove portion 19 and the slave groove portion 21. The liquid 31 that has penetrated into the absorption core 9 through the groove wall surface is absorbed by the absorption core 9 and forms the absorbed liquid 33. Therefore, even when the absorbent article 1 repeatedly absorbs the liquid, the liquid 31 that has reached the absorber 7 diffuses over a wide area of the absorber 7 through the main groove portion 19 and a wide range of the absorption core 9. Is absorbed by. As a result, in the absorbent article 1, the liquid absorbed by the absorbent core 9 does not easily return to the surface of the liquid permeable sheet 3, and the rewetability is excellent.

FIG. 7 is a diagram for explaining a state in which the absorbent article 1 according to the first embodiment has absorbed a liquid, and is a diagram corresponding to a part of FIG. Referring to FIG. 7A, when the liquid 31 that has reached the absorption core 9 is diffused through the main groove portion 19 and the slave groove portion 21, the main groove portion 19-1 having a large amount of liquid and the main groove portion having a small amount of liquid have a small amount of liquid. If there is 19-2, the liquid that has permeated from the slave groove portion 21-1 on the main groove portion 19-1 side with a large amount of liquid to the narrow portion 20-2 becomes a nominal liquid, and the main groove portion 19-2 side with a small amount of liquid It is possible to guide the liquid to the secondary groove portion 21-2 of the above. As a result, the absorption core 9 can exhibit liquid absorption performance (more efficient) by utilizing a wider width.

Referring to FIG. 7B, since the ridge 20 of the absorption core 9 is continuous in the longitudinal direction via the narrow portion 20-2, the liquid 33 in which the wide portion 20-1 of the ridge 20 is absorbed is absorbed. Even when the liquid 33 is filled with and the absorption capacity is lowered, the absorbed liquid 33 of the wide portion 20-1 can be diffused to the adjacent wide portion 20-1 in the longitudinal direction through the narrow portion 20-2. Therefore, the absorption capacity of the ridge 20 can be maintained. It is necessary that the absorption capacity does not decrease at the site where a large amount of liquid is received in order to fully exert the mechanism of liquid transport in the longitudinal direction using the main groove 19 in the case of repeatedly absorbing the liquid. It also contributes to the exertion of sexuality.

According to the shape and dimensions of the ridges and grooves of the first embodiment, the slave groove portion exists over the entire length of the absorption core 9 while keeping the width of the ridges 20 above a certain level, so that the absorption core 9 is flexible. It has a structure that can maintain its shape while having a structure, and is excellent in absorption performance and rewetability even after repeated absorption, so that the absorbent article 1 is excellent in wearing feeling.

In the absorbent article of the first embodiment, the absorbent core 9 and the core wrap 11 which are usually used in the art can be adopted without particular limitation. Examples of the absorbent core 9 include pulp fibers, highly absorbent polymers and the like, and examples of the core wrap include tissues.

The absorbent core 9 preferably contains water-absorbent fibers and a highly absorbent polymer and has an average basis weight of preferably 100 to 600 g / m ² , more preferably 200 to 500 g / m ² . The average basis weight of the water-absorbent fiber in the absorption core 9 is preferably 70 to 300 g / m ² , more preferably 100 to 250 g / m ² . The average basis weight of the highly absorbent polymer particles is preferably 30 to 300 g / m ² , and more preferably 100 to 250 g / m ² .

Each of the main groove portion 19 and the sub-groove portion 21, which is a low basis weight region as compared with the ridge portion 20, is preferably 5 to 80% by mass, more preferably 10 to 60% by mass, and further preferably 20 of the above average basis weight. It has a basis weight of ~ 40% by mass. Each of the main groove portion and the sub-groove portion, which is a low basis weight region, may have a basis weight of 0 g / m ² .

In the present specification, the average basis weight of the absorption core is obtained by cutting out five samples having a predetermined length and width from the absorption core (for example, 4 mm × 4 mm) and measuring the mass of each sample. Can be measured as the average value of the sample divided by the area of the sample.

[Second Embodiment]
The absorbent article of the second embodiment is the same disposable diaper as that of the first embodiment, but the shape and dimensions of the ridges and grooves provided in the absorbent core 9 are different from those of the first embodiment. Since the shape and dimensions of the ridges and grooves are the same as those of the first embodiment, the description thereof will be omitted.

FIG. 8 is a plan view of the absorption core 9 as viewed from the non-skin facing surface side, and FIG. 9 is an enlarged plan view of a part of FIG.

Referring to FIGS. 8 and 9, the ridges 20 extend in the longitudinal direction between the plurality of zigzag-shaped grooves 18 extending in the longitudinal direction Y of the absorption core 9, and the grooves 18 and the ridges 20 are in the lateral direction. Alternately present in X. The groove portion 18 has a width W _m , and the ridge portion 20 between the two groove portions 18 reaches from the narrowest portion to the widest portion by the zigzag-shaped groove portion 18 (dimension in the lateral direction X). Then, the change in width from the widest part to the narrowest part is repeated by the number of zigzags. _The width of the narrowest part is W2 _, and the width of the widest part is W3.

In the second embodiment, the narrowest portion of W ₂ is the narrow portion 20-2, and the other ridges 20 are the wide portions 20-1. In this example, the longitudinal dimension of the narrow portion 20-2 can be ignored, but in the second embodiment, the longitudinal dimension of the narrow portion 20-2 is the width of the groove portion at the maximum. In this example, the narrowest width W ₂ of the narrow portion 20-2 can be set as the minimum width of the narrow portion (dimension in the lateral direction X). Further, the length of the wide portion 20-1 ₍ dimension in the longitudinal direction Y) is the length L2 from the narrowest portion to the widest portion of the wide portion 20-1, and the narrowest portion from the widest portion. It is the sum of the length L ₂ to the part and is L ₁ . The width of the wide portion 20-1 (dimension in the lateral direction X) increases and decreases with a uniform inclination from W ₂ to W ₃ , and from W ₃ to W ₂ , and the maximum width is W ₃ . In the example of FIG. 9, the width of the wide portion 20-1 increases and decreases with a uniform slope from W ₂ to W ₃ and from W ₃ to W ₂ , so that the average value is (W ₂ + W). ₃ ) / 2 = W ₁ is calculated. In the present disclosure, as described above, the minimum and maximum values of the width of the ridges are smooth lines along the outer shape of the ridges in plan view to avoid the influence of unnecessarily minute dimensional changes. It is possible to draw a contour line and adopt the value of the part where the dimension is the minimum and the maximum.

In the second embodiment, for example, W _m is 4 mm, W ₂ is 6 mm, and W ₃ is 18 mm, which is the ratio of the minimum width of the narrow portion 20-2 to the maximum width of the wide portion 20-1. Is 6/18 = 33%. The length L ₁ of the wide portion 20-1 is 24 mm.

However, with the same shape as in FIG. 9, the widest width W ₃ of the wide portion 20-1 can be made wider than the above, for example, W _m can be 4 mm, W ₂ can be 6 mm, and W ₃ can be 30 mm. The constriction rate in that case is 6/30 = 20%.

Also in the second embodiment, the minimum width (dimension of X in the lateral direction) W ₂ of the narrow portion 20-2 has a predetermined relationship with the maximum width (dimension of X in the lateral direction) W ₃ of the wide portion 20-1. be. The second embodiment can be the same as the predetermined relationship described for the first embodiment. Further, in the second embodiment, the minimum width W ₂ of the narrow portion 20-2 has dimensions of 36% or less and 15% or more and 30% or less and 15% or more of the maximum width W ₃ of the wide portion 20-1. Is also preferable. Further, the minimum width (dimension of X in the lateral direction) W ₂ of the narrow portion 20-2 is preferably l2 to 15 mm, as in the first embodiment, and further is 2 mm or more and less than 10 mm, 4 to. It is preferably 8 mm.

In the second embodiment, the width, depth and number of grooves; the length, width and length / width ratio of the wide portion 20-1; the width of the narrow portion 20-2 (dimension in the lateral direction X). And the number, etc. can be selected in the same manner as the corresponding elements in the first embodiment, and the details thereof will not be described repeatedly, but such selection conditions are also preferable in the second embodiment.

In the second embodiment, the groove portion has a straight zigzag shape, but it is clear that a curved waveform may be used, and it is also clear that the shape factors and dimensions of the groove portion and the ridge portion at that time can be selected in the same manner as described above. be.

The absorption core having such a zigzag-shaped or corrugated groove has a predetermined ridge portion having a wide portion and a narrow portion, similar to the shape of the groove portion having the main groove portion and the sub-groove portion of the first embodiment. Due to the draw ratio, the absorption performance and rewetability after repetition are excellent as compared with the shapes of other known grooves.

[Third Embodiment]
The third embodiment is basically the same as the first embodiment, but the composition of the absorption core 9 is changed as follows.

Also in the third embodiment, the structures shown in FIGS. 1 to 7 for the first embodiment are basically the same. 10 and 11 are cross-sectional views of the absorption core 9 of the third embodiment cut by the line segment VV and the line segment VI-VI of FIG. 2 in the same manner as in FIGS. 5 and 6. Referring to FIGS. 10 and 11, the absorption core 9 has a two-layer structure of a first layer on the non-skin facing surface side and a second layer on the skin facing surface side. Referring to FIG. 10, in the first layer, the main groove portion 19 penetrates the first layer in the thickness direction Z, and the ridge portion 20 (wide portion 20-1) exists as the ridge portion 20. In the second layer, the main groove bottom layer 19B exists at the bottom of the main groove 19, and the portion corresponding to the ridge 20 constitutes the ridge lower layer 20B. Referring to FIG. 11, in the first layer, the main groove portion 19 and the sub-groove portion 21 penetrate the first layer in the thickness direction Z, and the ridge portion 20 (narrow portion 20-2) exists as the ridge portion 20. is doing. In the second layer, the main groove bottom layer 19B exists at the bottom of the main groove 19, and the follower bottom layer 21B exists at the bottom of the secondary groove 21, and corresponds to the ridge 20 (narrow portion 20-2). The portion to be formed constitutes the ridge lower layer 20B. In addition, in FIGS. 10 and 11, the bottom layer exists at the bottom of the main groove portion 19 and the slave groove portion 21, but the main groove portion 19 and the slave groove portion 21 penetrate the first layer and the second layer, and the bottom layer exists at the bottom. It is possible not to. Further, in the third embodiment, it is preferable that the main groove portion 19 and the sub-groove portion 21 are formed on the side of the non-skin facing surface 17.

In the third embodiment, what is the average density of the highly absorbent polymer particles (SAP) contained in the ridge 20 and the average density of the highly absorbent polymer particles contained in the main groove bottom layer 19B and the sub-groove bottom layer 21B, if present? Both are preferably lower than the average density of the highly absorbent polymer particles contained in the ridge lower layer 20B. If present, the average density of the highly absorbent polymer particles contained in the main groove bottom layer 19B and the sub-groove bottom layer 21B is preferably lower than the average density of the highly absorbent polymer particles contained in the ridge 20.

That is, most preferably, the average density of the highly absorbent polymer particles is (main groove bottom layer 19B and sub-groove bottom layer 21B) <(unebe 20) <(unebe lower layer 20B). When the average density of the highly absorbent polymer particles is large in this order, the liquid discharged to the skin facing surface of the absorption core is most likely to permeate the main groove bottom layer 19B and the sub-groove bottom layer 21B most quickly, and the main groove bottom layer 19B and the sub-groove bottom layer 19B are easily permeated. The liquid that permeates the groove bottom layer 21B and reaches the main groove 19 and the secondary groove 21, reaches the main groove 19 and the secondary groove 21, and flows along these grooves, permeates the ridge 20 through the groove wall surface, and is absorbed. However, the absorbed liquid is preferable because it moves to the ridge lower layer 20B, which has a higher average density of the highly absorbent polymer particles than the ridge 20, and more liquid is retained there.

In the third embodiment, the average basis weight of the water-absorbent fibers in the first layer and the second layer is preferably 50 to 150 g / m ² , more preferably 80 to 100 g / m ² . The average basis weight of the highly absorbent polymer particles is preferably 30 to 100 g / m ² in the first layer, more preferably 40 to 60 g / m ² , and preferably 100 to 180 g / m ² in the second layer. , More preferably 120 to 160 g / m ² . Further, the ratio of the average basis weight in the first layer to the average basis weight in the entire absorption core of the highly absorbent polymer particles is preferably 20 to 45%, more preferably 25 to 35%.

In the present disclosure, the average density of the highly absorbent polymer particles in the ridges is preferably 0 to 0.15 g / cm ³ , more preferably 0 to 0.1 g / cm ³ . The average density of the highly absorbent polymer particles in the bottom layer of the main groove portion and the bottom layer of the sub-groove portion is preferably 0 to 0.15 g / cm ³ , and more preferably 0 to 0.1 g / cm ³ . The average density of the highly absorbent polymer particles in the lower layer of the ridge is preferably 0.1 to 0.3 g / cm ³ , and more preferably 0.1 to 0.2 g / cm ³ .

In the present specification, the method for measuring the average density of the highly absorbent polymer particles is as follows. Five samples of a predetermined length and width are cut out from the absorption core (for example, 4 mm × 4 mm), the highly absorbent polymer particles contained in each sample are selected, and the total mass of the highly absorbent polymer particles contained in each sample is selected. Is measured, and this measured value is obtained by the average value obtained by dividing the measured value by the volume of the sample obtained by the thickness of the sample and the area of the sample, which will be described later.

[Manufacturing method of absorbent articles]
The production of the absorbent article of the present disclosure, particularly the production of the first embodiment and the second embodiment, can be basically carried out by a conventional method for producing an absorbent article.

In the third embodiment, the average density of the highly absorbent polymer particles is set to (main groove bottom layer 19B and secondary groove bottom layer 21B) <(ridge 20) <(ridge lower layer 20B), for example, as follows. Can be by. When an absorbent core material containing a water-absorbent fiber and a highly absorbent polymer is laminated on a rotatable suction drum to manufacture an absorbent core, a main groove and a secondary groove (collectively referred to as a groove) are formed on the surface of the suction drum. A mold member having a convex portion and a concave portion to be a ridge portion is installed, and only the concave portion is filled with high-absorbent polymer particles having a first average density to form a first layer, and then the convex portion of the mold member is formed. Highly absorbent polymer particles of the same average density are dropped all over the portions and recesses. At this time, if the falling speed of the highly absorbent polymer particles is adjusted, the highly absorbent polymer particles bounce off the convex portion of the mold member and are difficult to stay at the dropped position, whereas the mold is already filled with the absorbent core material. Bounce can be reduced at the position of the recess of the member. As a result, a second layer is formed in which the highly absorbent polymer is packed at a low density on the convex portion of the mold member and at a high density on the concave portion of the mold member, and the average density of the highly absorbent polymer particles of the obtained absorbent core is formed. Can be in the order of (second layer on the convex portion) <(first layer in the concave portion) <(second layer on the concave portion).

〔others〕
Although the disposable diapers have been described above, the absorbent articles of the present disclosure can be applied to absorbent articles such as incontinence pads and menstrual napkins other than disposable diapers.

Hereinafter, the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[Manufacturing Example 1] (with branch groove)
350 mm x 120 mm (longitudinal x lateral) size, 2.0 mm, including pulp (average basis weight: 170 g / m ² ) and highly absorbent polymer particles (average basis weight: 200 g / m ² ). Thickness absorption core No. 1 was manufactured. The densities of the pulp and the highly absorbent polymer particles were uniform in the thickness direction of the absorbent core.

Absorption core No. Reference numeral 1 has the shape shown in FIGS. 3 to 6, and four main groove portions (width: 4 mm) are arranged in the longitudinal direction at an interval of 18 mm (width of the wide ridge portion) on one surface of the absorption core. In each of the four main grooves, 14 sub-grooves (width 4 mm) are arranged symmetrically with a length of 6 mm in the lateral direction at intervals of 20 mm (length of the wide ridge). rice field. The distance between the sub-grooves (the width of the narrow ridge) was 6 mm. The depth of the main groove portion and the secondary groove portion was set to 1 mm.

The absorption core No. 1 was covered with two hydrophilic spunbonded non-woven fabrics (basis weight: 15 g / m ² , 400 mm × 150 mm) as a core wrap with a hot melt adhesive sandwiched between them. Absorption core No. covered with two hydrophilic spunbonded non-woven fabrics. The thickness of the absorption core was adjusted by pressing No. 1 with a hydraulic press, and the absorber No. 1 was adjusted. 1 was formed.

Absorber No. By attaching a liquid permeable sheet (air-through non-woven fabric) to the non-groove forming surface side of No. 1 and attaching a liquid permeable sheet (polyethylene film) to the groove forming surface side, a simple absorbent article No. 1 can be attached. 1 was manufactured.

[Manufacturing Example 2] (with zigzag groove)
Absorption core No. In No. 1, the absorbent article No. 1 was obtained in the same manner as in Production Example 1. 2 was manufactured, but the groove was changed to a zigzag groove. The zigzag groove has the shapes shown in FIGS. 10 and 11, and the groove width W _m = 4 mm, the groove depth 1 mm, the minimum width W ₂ = 6 mm of the narrow portion, and the maximum width W ₃ = of the wide portion. It was 18 mm.

[Manufacturing Example 3] (without groove)
Absorption core No. In No. 1, the absorbent article No. 1 is the same as in Production Example 1 except that the main groove portion and the sub-groove portion are not provided at all. 3 was manufactured.

[Manufacturing Example 4] (Parallel flutes only)
Absorption core No. In No. 1, the absorbent article No. 1 is provided in the same manner as in Production Example 1 except that the main groove portion is provided but the slave groove portion is not provided. 4 was manufactured.

[Manufacturing Example 5] (with a short branch groove)
Absorption core No. In 1, the absorbency is the same as in Production Example 1 except that the length of the slave groove portion (width 4 mm) is 3 mm and the distance between the slave groove portions (width of the narrow portion of the ridge) is 12 mm. Article No. 5 was manufactured.

[Manufacturing Example 6] (with a phase shift branch groove)
Absorption core No. In 1, the same as in Production Example 1 except that the positions of the secondary groove portions (width 4 mm) formed on both sides of the main groove portion are shifted by 3 mm in the longitudinal direction on both sides so that the secondary groove portions do not face each other. The absorbent article No. 6 was manufactured.

[Manufacturing Example 7] (with grid-like grooves)
Absorption core No. In the same manner as in Production Example 1, the absorbent article No. 1 was formed in the same manner as in Production Example 1, except that all the slave groove portions of No. 1 were connected in the lateral direction to form a grid-like groove structure. 7 was manufactured.

[Manufacturing Example 8] (with branch groove, with difference in SAP density)
Absorption core No. In No. 1, as shown in FIGS. 10 and 11, the 1 mm thick portion on the side where the main groove portion and the secondary groove portion are formed is used as the first layer, and the 1 mm thick portion on the opposite side is used as the second layer. In the same manner as in Production Example 1, the absorbent article No. 1 was produced except that the average basis weight ratio of the highly absorbent polymer particles (SAP) between the layer and the second layer was 30:70. 8 was manufactured.

This absorbent article No. In the production of 8, the production method described above was used as a method for adjusting the average basis weight of the highly absorbent polymer particles in the thickness direction of the absorption core, and pulp ( When the absorbent core material containing the average basis weight: 170 g / m ² ) and the highly absorbent polymer particles (average basis weight: 200 g / m ² ) is dropped, the drop speed is adjusted to adjust the first layer and the first layer. It was manufactured so that the average basis weight ratio of the highly absorbent polymer particles with the two layers was 30:70. Absorption core No. In No. 8, when the cross-sectional image on the surface intersecting the direction in which the main groove extends was visually evaluated, the average density of the highly absorbent polymer particles contained in the ridges and the average density of the highly absorbent polymer particles contained in the bottom layer of the main groove were evaluated. It was confirmed that the densities were all lower than the average density of the highly absorbent polymer particles contained in the lower layer of the ridge.

[Examples 1 to 3 and Comparative Examples 1 to 5]
Absorbent article No. 1 to No. No. 8 was subjected to the absorbability test specified below, and the absorption rate, the amount of liquid return, and the diffusion length on the liquid permeable sheet side were evaluated. The results are shown in Table 1. Absorbent article No. 1, No. 2 and No. 8 is Examples 1 to 3.

[Absorption test]
The absorbent article is set in a U-shaped device whose side view is substantially U-shaped so that the center position of the absorber in the longitudinal direction and the center of the U-shaped device (the lowest position) are aligned with each other. do.
<First cycle>
Inject 80 mL of artificial urine (first time) from the burette into the center position of the absorber at a rate of 80 mL / 10 seconds, and absorb the time (unit: seconds) until the artificial urine in the U-shaped instrument disappears. Record as time (80 mL). Three minutes after the start of infusion of artificial urine, the contour (80 mL) of the area where the artificial urine has diffused is recorded on a liquid permeable sheet of the absorbent article.
<2nd to 4th cycle>
10 minutes after the start of the first artificial urine injection, 3 minutes after the start of the second and third artificial urine injections, the first cycle is repeated with 80 mL of artificial urine, respectively. Three minutes after the start of the second to fourth infusion of artificial urine, the absorption time (160 mL), absorption time (240 mL) and absorption time (320 mL) were measured, and the contour (160 mL), contour (240 mL) and contour (240 mL) were measured. 320 mL) is recorded.

Four minutes after the start of the fourth injection of artificial urine, the absorbent article is taken out from the U-hour instrument, spread on an acrylic flat plate so that the liquid-permeable sheet faces the upper surface, and allowed to stand for 1 minute. Five minutes after the start of the fourth injection of artificial urine, 60 g of 100 mm × 100 mm filter paper was placed on a liquid-permeable sheet of an absorbent article centering on the artificial urine injection point, and 3.5 kg of the filter paper was placed on the filter paper. A weight of 100 mm × 100 mm × 50 mm (height) is allowed to stand still. Eight minutes after the start of the fourth injection of artificial urine, the mass of the filter paper is measured, the mass of the filter paper before the test (measured in advance) is subtracted, and the difference is taken as the liquid return amount (rewet).

From the contour of the region where the artificial urine has diffused (160 mL to 320 mL), the diffusion length of the artificial urine in the longitudinal direction of the absorbent article is measured.

The artificial urine was prepared by dissolving 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride and about 1 g of dye: Blue No. 1 in 10 L of ion-exchanged water.

When the absorbent article of Example 1 having completed the four-cycle absorbability test was compared with the absorbent article of Comparative Examples 1 to 6, superiority was observed in the absorption time and the amount of liquid return. In the absorbent article of Example 3, the absorption time and the amount of liquid return were further superior to those of the absorbent article of Example 1.

[Wearing feeling test]
When the absorbent articles of Examples and Comparative Examples were worn by a plurality of volunteer subjects, the absorbent articles of Examples 1 to 3 had good absorption performance even after urinating four or more times, and were not good. We received the answer that there was little pleasure. Furthermore, it was answered that the rigidity is relatively low and the fit is excellent even after urinating four times or more.

1 Absorbent article 3 Liquid permeable sheet 5 Liquid permeable sheet 7 Absorbent 9 Absorbent core 11 Core wrap 15 Skin facing surface 17 Non-skin facing surface 18 Groove 19 Main groove 19B Main groove bottom layer 20 Ridge 20B Ridge lower layer 20- 1 Wide part 20-2 Narrow part 21 Sub-groove part 21B Sub-groove bottom layer 31 Liquid 33 Absorbed liquid Y Longitudinal direction X Short direction Z Thickness direction

Claims (8)

An absorbent article comprising an absorbent core having a longitudinal direction, a lateral direction and a thickness direction, wherein the absorbent core has one surface and the other surface.
The absorption core has a plurality of ridges extending in the longitudinal direction and a plurality of grooves extending in the longitudinal direction on one surface thereof, and the ridges and the grooves are short sides thereof. Alternately in the direction,
The groove portion includes a plurality of main groove portions extending in the longitudinal direction and a plurality of slave groove portions extending from the main groove portion in the lateral direction.
The secondary groove portions extending in the lateral direction from each of the main groove portions adjacent to each other in the lateral direction face each other, and a narrow portion of the ridge is formed between the secondary groove portions facing each other. , The portion of the ridge other than the narrow portion is a wide portion.
The constriction rate, which is the ratio of the minimum dimension of the narrow portion in the lateral direction to the maximum dimension of the wide portion in the lateral direction, is 10% or more and 50% or less.
The absorption core is composed of the groove portion, the groove bottom layer at the lower part of the groove portion, the ridge portion, and the ridge lower layer at the lower portion of the ridge portion in the cross section including the groove portion, and is described above. The ridges and the lower layer of the ridges contain highly absorbent polymer particles, and the bottom layer of the grooves may or may not contain the highly absorbent polymer particles, and the average density of the highly absorbent polymer particles contained in the ridges. When the groove bottom layer contains the highly absorbent polymer particles, the average density of the highly absorbent polymer particles contained in the groove bottom layer is the same as that of the highly absorbent polymer particles contained in the ridge lower layer. Absorbent article characterized by being lower than average density . The absorbent article according to claim 1, wherein the dimension of each of the wide portions in the longitudinal direction is 1.0 to 2.0 times the average dimension of each of the wide portions in the lateral direction. The absorbent article according to any one of claims 1 or 2, wherein the groove is four or more. The absorbent article according to any one of claims 1 to 3, wherein the width of the groove is 1 to 3 times the thickness of the absorbent core. An absorbent article comprising a liquid permeable sheet, a liquid permeable sheet, and an absorbent core between the liquid permeable sheet and the liquid permeable sheet, wherein the absorbent core is longitudinally oriented and short. It has a direction and a thickness direction, and has a skin facing surface and a non-skin facing surface , and the absorption core includes a core wrap that covers the skin facing surface and the non-skin facing surface.
The absorption core has a plurality of ridges extending in the longitudinal direction and a plurality of grooves extending in the longitudinal direction on the non-skin facing surface , and the ridges and the grooves are short. Alternately in the hand direction ,
The core wrap covering the non-skin facing surface side did not abut on the bottom of the groove of the absorption core.
The groove portion is zigzag-shaped or corrugated in the longitudinal direction, and the groove portions adjacent to each other in the lateral direction have zigzag-shaped or corrugated protrusions approaching each other and facing each other. A narrow portion of the ridge is formed between the ridges, and a portion of the ridge other than the narrow portion is a wide portion.
An absorbent article having a constriction rate of 10% or more and 50% or less, which is a ratio of the minimum dimension of the narrow portion in the lateral direction to the maximum dimension of the wide portion in the lateral direction. The absorbent article according to claim 5, wherein the lengthwise dimension of each of the wide portions is 1.0 to 2.0 times the average dimension of each of the wide portions in the lateral direction. The absorbent article according to claim 5 or 6, wherein the groove is three or more. The absorbent article according to any one of claims 5 to 7, wherein the width of the groove is 1 to 3 times the thickness of the absorbent core.

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