CN113784695B

CN113784695B - Absorbent article

Info

Publication number: CN113784695B
Application number: CN202080032714.4A
Authority: CN
Inventors: 川口宏子; 松田昂平
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2019-06-28
Filing date: 2020-05-11
Publication date: 2022-11-11
Anticipated expiration: 2040-05-11
Also published as: CN113784695A; WO2020261779A1; JP6840791B2; JP2021007515A

Abstract

The invention provides an absorbent article having an absorbent body (5), the absorbent body (5) having an absorbent core (6) and a core-covering sheet (7), the absorbent core (6) being formed of an assembly of a super absorbent polymer (67) and pulp fibers (68), the absorbent core (6) being divided in the thickness direction into a front portion (61) located on the skin surface side, a back portion (62) located on the non-skin surface side, and a thickness direction central portion (63) located between the front portion (61) and the back portion (62), the thickness direction central portion (63) being formed as a super absorbent polymer high-density layer in which the mass ratio of the super absorbent polymer (67) to the pulp fibers (68) is greater than that of the front portion (61) and the back portion (62).

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article.

Background

A super absorbent polymer (a surface cross-linked polymer material called SAP) used in an absorbent article such as a diaper is sometimes oxidized to become yellow or brown in color under a high-temperature and high-humidity environment, and the appearance of the absorbent article is sometimes deteriorated. Such a phenomenon is likely to occur particularly in subtropical or tropical areas such as southeast asia. Therefore, a technique has been proposed so far for suppressing discoloration of a super absorbent polymer using an antioxidant or the like and maintaining a good appearance of an absorbent article.

For example, patent document 1 describes a technique of using acrylic acid or a quinone hydroquinonization inhibitor having a small content of hydroquinone, patent document 2 describes a technique of using a reducing compound and a specific acid (salt), and patent document 3 describes a technique of using a sulfinic acid derivative.

On the other hand, a technique of disposing a large amount of superabsorbent polymer at a specific site has been proposed. For example, patent document 4 describes an absorbent article in which an absorbent body having a high content ratio of a polymer absorbent body on the front material side and a low content ratio of a polymer absorbent body on the back material side is interposed. Patent document 5 describes an absorbent body having an absorbent core containing 50 parts by mass or more of particulate absorbent polymer within a predetermined range.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 11-322846

Patent document 2: japanese patent laid-open publication No. 2003-52742

Patent document 3: japanese unexamined patent publication No. 2006-521431

Patent document 4: japanese laid-open patent publication No. 2009-119154

Patent document 5: japanese patent laid-open publication No. 2018-47189

Disclosure of Invention

The present invention provides an absorbent article having an absorbent body including an absorbent core and a core-covering sheet covering the periphery of the absorbent core, wherein the absorbent core is formed of an assembly of a super absorbent polymer and pulp fibers, the absorbent core is divided in the thickness direction into a front surface portion located on the skin surface side, a back surface portion located on the non-skin surface side, and a thickness direction center portion located between the front surface portion and the back surface portion, and the thickness direction center portion is formed as a high-absorbent polymer high-density layer in which the mass ratio of the super absorbent polymer to the pulp fibers is larger than that of the front surface portion and the back surface portion.

The above and other features and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings, where appropriate.

Drawings

Fig. 1 is a perspective view showing a diaper according to a preferred embodiment of the absorbent article of the present invention.

Fig. 2 is a partially cut-open plan view schematically showing the diaper shown in fig. 1 in a state where the side seal is torn open, stretched, and viewed from the skin surface side.

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

Fig. 4 is a plan view schematically showing an absorbent core included in the diaper of fig. 2.

FIG. 5 (A) isbase:Sub>A sectional view taken along line A-A of FIG. 4, and (B) isbase:Sub>A sectional view taken along line B-B of FIG. 4.

Fig. 6 is a plan view schematically showing another preferred embodiment of the absorbent core included in the diaper of fig. 2.

Fig. 7 is a cross-sectional view schematically showing a state in which the core-covering sheets on the skin surface side and the non-skin surface side are joined to each other in the slit portion of the absorbent core of fig. 6.

Detailed Description

The present invention relates to an absorbent article capable of maintaining a good appearance without using a super absorbent polymer containing a component for inhibiting discoloration.

In the techniques described in patent documents 1 to 3, an expensive super absorbent polymer containing a component for suppressing discoloration such as an antioxidant has to be used, and the price of the absorbent article is increased.

In contrast, the absorbent article of the present invention can maintain a good appearance.

Hereinafter, a diaper which is a preferred embodiment of the absorbent article of the present invention will be described with reference to the drawings.

In the present invention, the side in contact with the skin of the wearer is referred to as the skin surface side or the skin contact surface side or the front surface side, and the opposite side is referred to as the non-skin surface side or the non-skin contact surface side or the back surface side. These terms are used as terms indicating relative positional relationships among component structures of an absorbent article, even for components that do not have a surface that contacts the skin of the wearer. The normal direction to the front or back of the absorbent article is referred to as the thickness direction.

As shown in fig. 1, the diaper 10 of the present embodiment includes an absorbent main body 1 and an outer package 2. The exterior body 2 has a front side exterior body 21 and a rear side exterior body 22 corresponding to the front side and the rear side of the wearer, respectively. The front side is the abdominal side of the wearer, and the back side is the back side of the wearer. The front outer cover 21 and the rear outer cover 22 are laterally long (laterally long), and both side edges thereof are overlapped and joined at the side seals 11 to form an annular waistline portion 10D of the diaper 10. The portion of the absorbent main body 1 extending from the outer cover 2 forms the intermediate portion 10C of the diaper 10. The diaper 10 has a waist opening 12 which opens above the waist portion 10D, and a pair of

leg openings

13, 13 which open on both the left and right sides of the intermediate portion 10C.

Fig. 2 shows the diaper 10 in a state where the

side seals

11, 11 are torn apart and unfolded. The unfolded state is a state in which the respective portions are extended to expand the absorbent article into a flat shape.

The diaper 10 is divided into front side portions 10F, an intermediate portion 10C, and back side portions 10R in an unfolded state. The front side outer package 21 and the rear side outer package 22, which are laterally long, are disposed in the front side portion 10F and the rear side portion 10R, respectively. The vertically long absorbent body 1 is disposed on the skin surface side of the front outer cover 21 and the back outer cover 22 so that the longitudinal direction thereof faces the front section 10F, the intermediate section 10C, and the back section 10R of the diaper 10. In this arrangement, the absorbent main body 1 has a longitudinal direction Y corresponding to a direction in which the front side, the middle, and the rear side of the wearer are continuous, and a width direction X orthogonal to the longitudinal direction Y. At the front and rear end portions in the longitudinal direction Y of the absorbent main body 1, the front side outer package 21 and the rear side outer package 22, which are not on the skin surface side, are folded back toward the skin surface side of the absorbent main body 1 and joined to the skin surface side of the absorbent main body 1. Thereby, the skin surface side and the non-skin surface side of the front and rear ends in the longitudinal direction Y of the absorbent main body 1 are covered with the front outer cover 21 and the rear outer cover 22.

As shown in fig. 3, the absorbent body 1 constituting the diaper 10 includes a liquid-permeable front sheet 3 on the skin surface side, a leakproof back sheet 4 on the non-skin surface side, and a liquid-retaining absorbent body 5 disposed between the front sheet 3 and the back sheet 4. The absorber 5 has an absorbent core 6 formed of an aggregate of a super absorbent polymer 67 and pulp fibers 68, and a core sheet 7 covering the outer periphery of the absorbent core 6. The core-spun sheet 7 is formed of a material having hydrophilicity, for example, hydrophilic paper or nonwoven fabric.

In the present embodiment, the pair of side sheets 9 is provided on both sides of the absorbent main body 1 in the longitudinal direction Y. An elastic member 91 extending in the longitudinal direction Y is disposed at an inner end of the side sheet 9 in the width direction X, and a three-dimensional gather portion 92 is formed. Further, at the outer end portion in the width direction X of the side sheet 9, an elastic member 93 in a state of being stretched in the longitudinal direction Y is disposed, and a leg gather portion 94 is formed. In the absorbent body 1 of the present embodiment, the outer-covering nonwoven fabric 48 is disposed on the non-skin surface side of the back sheet 4.

As shown in fig. 2, the absorbent core 6 has a longitudinal direction Y and a width direction X orthogonal to the longitudinal direction, similarly to the absorbent main body 1. As shown in fig. 2 and 3, the core sheet 7 covers the entire length direction Y of the absorbent core 6 and extends in the width direction X, and covers and is wound around the skin surface side, both sides, and non-skin surface side (outer periphery) of the absorbent core 6. The wound core-spun sheet 7 has ends in the width direction X laminated to each other, and a laminated portion 75 is formed over the entire length of the absorbent core 6 in the longitudinal direction Y. In fig. 3, the laminated portion 75 of the core sheet 7 is disposed 1 on the non-skin surface side of the absorbent core 6, but is not limited thereto. For example, the number of the cells may be 2 or more on the skin surface side, or on the non-skin surface side or the skin surface side. From the viewpoint of liquid absorbency, it is preferable that 1 laminate section 75 of the core sheet 7 is disposed on the non-skin surface side of the absorbent core 6.

As shown in fig. 4, the absorbent core 6 is divided into a front portion F, an intermediate portion C, and a rear portion R by equally dividing the length 3 in the longitudinal direction Y. The absorbent core 6 has a liquid receiving area Q for directly receiving an excretion liquid such as urine. In the diaper 10, the liquid receiving area Q is an area within 3.5cm in the left and right lateral directions from a line S1 bisecting the length in the lateral direction X and within 8cm in the front side portion F direction from a line M1 bisecting the length in the longitudinal direction Y.

In the absorbent article of the present invention, the dividing positions of the front portion F, the intermediate portion C, and the rear portion R and the liquid receiving region Q are appropriately set according to the type of the absorbent article and the like. For example, in the case where the absorbent article of the present invention is a sanitary napkin for daily use, the front portion F, the intermediate portion C, and the rear portion R are divided in the same manner as in the case of the diaper 10 described above, and the liquid receiving region Q is a region within 2.5cm in the left-right width direction from a line that divides the length 2 of the intermediate portion C in the width direction X into equal parts in the intermediate portion C. In the case where the absorbent article of the present invention is a rear flap having a wide width for covering buttocks for night use or the like, the first section is a front portion F, the second section is an intermediate portion C, and the remaining is a rear portion R at 4 equal divisions in the longitudinal direction Y. The liquid receiving region Q in this case is a region within 2.5cm in the right-left width direction of the intermediate portion C from a line bisecting the length 2 in the width direction X of the intermediate portion C. In addition, when the absorbent article of the present invention is a urine collection pad or an incontinence pad, the same configuration as the diaper 10 is established.

As shown in fig. 5 (a), the absorbent core 6 is divided in the thickness direction into a front portion 61 positioned on the skin surface side, a back portion 62 positioned on the non-skin surface side, and a thickness direction central portion 63 positioned between the front portion 61 and the back portion 62. This division is performed by equally dividing the absorbent core 6 in the thickness direction 3.

The thickness direction central portion 63 of the absorbent core 6 is formed as a high-absorbent polymer high-density layer in which the mass ratio of the high-absorbent polymer 67 to the pulp fibers 68 is larger than that of the front portion 61 and the back portion 62. The high-density layer of high-absorbency polymer may be a part of the thickness direction central portion 63, and is preferably present in the entire planar region of the thickness direction central portion 63. As described above, the superabsorbent polymers 67 are disposed in a large amount inside the absorbent core 6, and the superabsorbent polymers 67 contained in the absorbent core 6 are distributed unevenly. This makes the superabsorbent polymer 67 inside less likely to contact air, and can suppress discoloration associated with oxidation. In addition, since the superabsorbent polymer 67 has a high density, the rate of discoloration can be suppressed. Further, since the front surface portion 61 and the back surface portion 62 are formed of a layer containing more pulp fibers 68 than the thickness direction central portion 63, even if the superabsorbent polymer 67 in the inner portion is discolored, the discoloration is not easily seen from the outside of the diaper 10, and the good appearance of the diaper 10 can be maintained. The high-density layer of the super absorbent polymer formed in the thickness direction central portion 63 may be a single layer or a plurality of layers as long as it is a portion divided into intermediate portions of the absorbent core 6 equally divided by the thickness 3.

From the viewpoint of suppressing the discoloration of the super absorbent polymer 67, making the discoloration less likely to be seen from the outside of the diaper 10, and maintaining the absorbency of the absorbent body 5, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the thickness direction central portion 63 is preferably 1.0 or more, more preferably 1.25 or more, and even more preferably 1.5 or more. In addition, from the viewpoint of not deteriorating the liquid returning property of the absorbent body 5 under pressure, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the thickness direction central portion 63 is preferably 2.0 or less, more preferably 1.8 or less, and further preferably 1.6 or less. Specifically, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 is preferably 1.0 or more and 2.0 or less, more preferably 1.25 or more and 1.8 or less, and further preferably 1.5 or more and 1.6 or less in the thickness direction central portion 63.

From the viewpoint of not deteriorating the liquid returning property of the absorbent body 5 under pressure, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the front surface portion 61 and the back surface portion 62 is preferably 0.25 or more, more preferably 0.38 or more, and still more preferably 0.4 or more. In addition, from the viewpoint that discoloration of the superabsorbent polymer 67 inside is less likely to be visible on the outside of the diaper 10, the mass ratio of the superabsorbent polymer 67 to the pulp fibers 68 in the front portion 61 and the back portion 62 is preferably 0.75 or less, more preferably 0.63 or less, and still more preferably 0.5 or less. Specifically, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 is preferably 0.25 or more and 0.75 or less, more preferably 0.38 or more and 0.63 or less, and still more preferably 0.4 or more and 0.5 or less in the front surface portion 61 and the back surface portion 62.

The mass ratio of the superabsorbent polymer 67 to the pulp fibers 68 in the thickness direction central portion 63 is preferably 1.3 times or more, more preferably 2.0 times or more, and even more preferably 3.0 times or more, with respect to the mass ratio of the superabsorbent polymer 67 to the pulp fibers 68 in the front surface portion 61 and the back surface portion 62. This makes it possible to more reliably achieve both suppression of discoloration of the super absorbent polymer 67, prevention of discoloration from being easily seen from the outside of the diaper 10, and maintenance of the absorbency of the absorbent body 5. In addition, from the viewpoint of not deteriorating the liquid returning property of the absorbent body 5 at the time of pressurization, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the thickness direction central portion 63 is preferably 8 times or less, more preferably 5 times or less, and still more preferably 4 times or less, with respect to the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the front surface portion 61 and the back surface portion 62.

Specifically, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the thickness direction center portion 63 is preferably 1.3 times or more and 8 times or less, more preferably 2.0 times or more and 5 times or less, and still more preferably 3.0 times or more and 4 times or less, with respect to the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 in the front surface portion 61 and the back surface portion 62.

(method of measuring the mass ratio of the super absorbent polymer 67 to the pulp fibers 68)

First, a cross section of a measurement target portion of the absorbent core 6 was observed with a microscope and divided equally in the thickness direction 3, and the front surface portion 61, the thickness direction central portion 63, and the rear surface portion 62 were taken.

Regarding each part used, the mixture of the super absorbent polymer 67 and the pulp fibers 68 was quantified by the method for quantifying the fiber and/or the water-absorbent polymer described in japanese patent No. 4225821, and the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 was calculated.

Specifically, the mass of each collected portion was measured, and then the superabsorbent polymer 67 was reduced in molecular weight in each portion. The high-absorbency polymer 67 can be reduced in molecular weight by ultraviolet irradiation. At this time, the mixture of the super absorbent polymer 67 and the pulp fibers 68 collected for each site is put in a mesh bag or the like and immersed in an aqueous solution containing ascorbic acid and riboflavin. After swelling the super absorbent polymer by immersion, the mesh bag was taken out from the aqueous solution and irradiated with the ultraviolet ray described above to reduce the molecular weight of the super absorbent polymer 67. Subsequently, components generated by the reduction of molecular weight are removed by washing with water. The removed mesh bag was sufficiently washed with water, dehydrated and dried and measured for mass. The mass of the pulp fiber 68 was calculated by subtracting the mass of the mesh bag alone from the measured mass, and the mass of the pulp fiber 68 was subtracted from the mass of each portion measured initially to obtain the mass of the super absorbent polymer 67. Based on this, the mass ratio of the super absorbent polymer 68 to the pulp fibers 68 in each portion was calculated. The average value of the mass ratios obtained by performing the above-described measurements three times is taken as the mass ratio in each portion of the front surface portion 61, the thickness direction central portion 63, and the back surface portion 62.

As an example of a method of forming the thickness direction central portion 63 of the absorbent core 6 as the high-density layer of the super absorbent polymer, it is conceivable that an SAP tube into which the super absorbent polymer 67 (SAP) is put is designed as follows in a manufacturing apparatus of the absorbent core.

First, as the manufacturing apparatus, a manufacturing apparatus including a rotating drum having a collecting recess on an outer peripheral surface thereof and a fiber material tube for supplying a fiber material to the rotating drum so as to be carried by an air flow is used. In this manufacturing apparatus, a first SAP pipe and a second SAP pipe that supply a super absorbent polymer 67 (SAP) to the fiber material pipe are provided. The first SAP pipe is disposed on the upstream side of the supply pipe of the pulp fibers 68 than the second SAP pipe.

In this manufacturing apparatus, the mass ratio of the super absorbent polymer 67 fed from the first SAP pipe and the second SAP pipe is appropriately set, and the position where the super absorbent polymer is blended with high density can be controlled. For example, when the mass of the super absorbent polymer 67 input from the first SAP pipe is increased relative to the mass of the super absorbent polymer 67 input from the second SAP pipe, the super absorbent polymer 67 can be blended more toward the thickness direction central portion 63 side than the front portion 61 of the absorbent core 6.

In addition, the position where the super absorbent polymer is blended at high density can also be controlled by appropriately setting the insertion depth of the tube. For example, when the insertion depth of the tube is made larger, more superabsorbent polymer is blended on the thickness direction center portion 63 side than on the front surface portion 61 of the absorbent core 6.

As described above, by appropriately setting the number of SAP pipes, the mass of the super absorbent polymer 67 fed from the SAP pipes, and the insertion depth of the SAP pipes, the thickness direction central portion 63 of the absorbent core 6 can be formed as a high-density layer of the super absorbent polymer.

In the diaper 10, a member having a colored portion is preferably disposed on at least one of the skin surface side and the non-skin surface side of the absorbent core 6. This makes it possible to make the discoloration of the super absorbent polymer 67 less noticeable when viewed from the outside of the diaper 10. From the viewpoint of maintaining a good appearance during wearing, the member having the colored portion is more preferably present on the non-skin surface side of the absorbent core 6, and is further preferably present on both the skin surface side and the non-skin surface side. When the member having the colored portion is disposed on both the skin surface side and the non-skin surface side, the discoloration of the super absorbent polymer 67 can be made less noticeable on both sides of the diaper before and after wearing.

Examples of the member having a colored portion on the skin surface side of the absorbent core 6 include the core sheet 7 and the topsheet 3. When an intermediate sheet (not shown) is further provided between the topsheet 3 and the core sheet 7, the intermediate sheet is also included in the skin surface side member of the absorbent core 6. Examples of the member having a colored portion on the non-skin surface side of the absorbent core 6 include the core sheet 7, the back sheet 4, and the outer-covering nonwoven fabric 48. Further, with respect to the front side outer body 21 and the rear side outer body 22, the portion folded back to the skin surface side of the absorbent main body 1 becomes a member on the skin surface side of the absorbent core 6, and the portion disposed on the non-skin surface side of the absorbent main body 1 becomes a member on the non-skin surface side of the absorbent core 6.

The "colored portion" refers to a portion where a coloring agent is applied to a member, and may be a portion colored in a predetermined pattern or a portion applied over the entire surface. The colored portion may be a portion for displaying characters, patterns, or the like. The "colored portion" is preferably a region of 10% or more of the area of the member.

The "color" in the colored portion is not limited to a chromatic color, and may be an achromatic color. The "color" is preferably darker than the color (for example, yellow or brown) of the high absorbent polymer 67 after the color change or a complementary color to the color after the color change, from the viewpoint of making the color change of the high absorbent polymer 67 in the absorbent core 6 less noticeable. Specifically, green, blue, and violet are preferable.

The colored portion is preferably positioned so as to overlap with the

end portions

6E, 6E in the longitudinal direction Y of the absorbent core 6 in plan view. Thus, even if the superabsorbent polymer 67 moves from the inside of the absorbent core 6, for example, from the central portion 63 in the thickness direction, which is a high-density layer of the superabsorbent polymer, for some reason and is collected at the

end portions

6E and 6E where the pulp fibers 68 are few, the discoloration of the superabsorbent polymer 67 can be made less visible from the outside. When an impact is applied during the production, transportation, or the like of the diaper 10, the super absorbent polymer 67 may move inside the absorbent core 6 and reach the

end portions

6E, 6E of the absorbent core 6. In particular, in the present embodiment, since the central portion 63 in the thickness direction of the absorbent core 6 becomes a high-density layer of the high-absorbency polymer, the high-absorbency polymer 67 more easily moves to the end portions 6E. Therefore, when the end portion of the absorbent core 6 is hidden by the colored portion, the super absorbent polymer 67 moved to the end portion of the absorbent core 6 is not easily seen, which is preferable. In particular, from the viewpoint of effectively making the discolored super absorbent polymer 67 less visible, it is more preferable that the colored portion of the back sheet 4 is formed as a portion coated with a colorant over the entire surface thereof, and the position of the colored portion overlaps with the positions of the

end portions

6E, 6E of the absorbent core 6 in a plan view.

As shown in fig. 4, a high grammage region 6H and a low grammage region 6L having a lower grammage than the high grammage region 6H are preferably arranged in a plan view of the absorbent core 6. The grammage of the high grammage region 6H and the low grammage region 6L is the grammage including both the high absorbent polymer 67 and the pulp fibers 68 constituting the absorbent core 6.

When the planar region of the absorbent core 6 is divided into the front portion F, the intermediate portion C including the liquid receiving region Q, and the rear portion R in the longitudinal direction Y, the high grammage region 6H preferably includes at least the liquid receiving region Q of the intermediate portion C, and the low grammage region 6L preferably includes at least the rear portion R.

The high grammage region 6H "the liquid receiving region Q including at least the intermediate portion C" means that the high grammage region 6H includes the liquid receiving region Q of the intermediate portion C, and may include regions other than the liquid receiving region Q. For example, the high grammage region 6H may include the entire intermediate portion C or a part thereof, or may include not only the intermediate portion C but also a part of either one of the front portion F and the rear portion R. The high grammage region 6H preferably includes not only the intermediate portion C but also at least a part of the front portion F, and more preferably includes the entirety of the intermediate portion C and the front side portion F. The low grammage region 6L "including at least the rear portion R" means that the low grammage region 6L includes the rear portion C, and may include regions other than the rear portion C, and may include a part of the intermediate portion C, for example. The high grammage region 6H is preferably equal in grammage at any portion when viewed in the width direction X (except for a slit portion 8 described later). It is preferable that the low grammage region 6L has the same grammage at any portion when viewed in the width direction X (except for a slit portion 8 described later).

As shown in fig. 5 (B), the high grammage region 6H and the low grammage region 6L include the entire thickness of the absorbent core 6 in the respective planar regions, that is, the entire front portion 61, the thickness direction central portion 63, and the back portion 62 described above. As described above, the high grammage region 6H includes at least the liquid receiving region Q, thereby increasing the absorption capacity of the region of the absorbent core 6 having a large liquid receiving amount. This makes it difficult to see the discoloration of the super absorbent polymer 67 from the outside by forming the thickness direction central portion 63 as a high density layer of the super absorbent polymer, and also makes it possible to increase the absorption capacity around the liquid receiving region Q, thereby suppressing rewet (return of the absorbed liquid to the skin side). In addition, due to the above-mentioned uneven distribution of the super absorbent polymer 67, it is possible to suppress an increase in the amount of the super absorbent polymer 67 while securing the absorption capacity, and to make the discoloration of the super absorbent polymer 67 less noticeable. In addition, the degree of swelling during liquid absorption in the low grammage region L can be suppressed, and pressing on the waist of the wearer can be suppressed. The high grammage region 6H and the low grammage region 6L can be measured by the same method as described above (the method of measuring the mass ratio of the super absorbent polymer 67 to the pulp fibers 68).

From the viewpoint of making the above-described effect more remarkable, the grammage of the high grammage region 6H is preferably 120% or more, and more preferably 140% or more, with respect to the grammage of the low grammage region 6L. The grammage of the high grammage region 6H is preferably 250% or less, and more preferably 230% or less, relative to the grammage of the low grammage region 6L. Specifically, the grammage of the high grammage region 6H is preferably 120% or more and 250% or less, and more preferably 140% or more and 230% or less, with respect to the grammage of the low grammage region 6L.

In the range of the ratio of the grammage of the high grammage region 6H to the grammage of the low grammage region 6L, the grammage of the high grammage region 6H is preferably 150g/m ² Above, more preferably 200g/m ² The content of the above is more preferably 250g/m ² The above. Further, the grammage of the high grammage region 6H is preferably 900g/m ² Hereinafter, 850g/m is more preferable ² Hereinafter, it is more preferably 800g/m ² The following. Specifically, the grammage of the high-grammage region 6H is preferably 150g/m ² Above and 900g/m ² Hereinafter, more preferably 200g/m ² Above and 850g/m ² Hereinafter, it is more preferably 250g/m ² Above and 800g/m ² The following.

In the range of the ratio of the grammage of the high grammage range 6H to the grammage of the low grammage range 6L, the grammage of the low grammage range 6L is preferably 100g/m ² Above, more preferably 150g/m ² The above is more preferably 200g/m ² As described above. Further, the grammage of the low-grammage region 6L is preferably 600g/m ² Hereinafter, 550g/m is more preferable ² Hereinafter, it is more preferably 500g/m ² The following. Specifically, the grammage of the low-grammage region 6L is preferably 100g/m ² Above and 600g/m ² Hereinafter, it is more preferably 150g/m ² Above and 550g/m ² Hereinafter, more preferably 200g/m ² Above and 500g/m ² The following.

The relationship between the grammage of the high grammage region 6H and the grammage of the low grammage region 6L is preferably also applied to the relationship between the grammage of the super absorbent polymer 67 and the pulp fiber 68. That is, the grammage of the super absorbent polymer 67 constituting the high grammage region 6H is preferably higher than that of the super absorbent polymer 67 constituting the low grammage region 6L. Further, the grammage of the pulp fibers 68 constituting the high grammage region 6H is preferably higher than that of the pulp fibers 68 constituting the low grammage region 6L.

From the viewpoint of making the above-described effect more remarkable, the length of the high grammage region 6H in the longitudinal direction Y of the absorbent core 6 is preferably 50% or more, more preferably 60% or more, and still more preferably 70% or more of the entire length of the absorbent core 6. The length of the high grammage region 6H in the longitudinal direction Y of the absorbent core 6 is preferably 90% or less, more preferably 85% or less, and still more preferably 80% or less of the entire length of the absorbent core 6. Specifically, the length of the high grammage region 6H in the longitudinal direction Y of the absorbent core 6 is preferably 50% or more and 90% or less, more preferably 60% or more and 85% or less, and still more preferably 70% or more and 80% or less of the entire length of the absorbent core 6.

From the viewpoint of making the above-described effect more remarkable, the length of the low grammage region 6L in the longitudinal direction Y of the absorbent core 6 is preferably 10% or more, more preferably 15% or more, and still more preferably 20% or more of the entire length of the absorbent core 6. The length of the low grammage region 6L in the longitudinal direction Y of the absorbent core 6 is preferably 50% or less, more preferably 40% or less, and still more preferably 30% or less of the entire length of the absorbent core 6. Specifically, the length of the low grammage region 6L in the longitudinal direction Y of the absorbent core 6 is preferably 10% or more and 50% or less, more preferably 15% or more and 40% or less, and still more preferably 20% or more and 30% or less of the entire length of the absorbent core 6.

In the high grammage region 6H and the low grammage region 6L, a difference in thickness due to a grammage difference may be generated or may not be generated. In the high grammage region 6H and the low grammage region 6L, the mass ratio of the super absorbent polymer 67 to the pulp fibers 68 may or may not be different.

The high grammage region 6H and the low grammage region 6L can be manufactured by forming a low air permeability in a part of the air permeable member constituting the bottom of the collecting recess in the collecting recess disposed on the outer peripheral surface of the rotary drum, the part being to become the low grammage region 6H.

Further, a member having the colored portion is disposed on the non-skin surface side of the absorbent core 6, and the high grammage region 6H is preferably overlapped with the position of the colored portion in a plan view of the absorbent core 6. This can increase the absorption capacity around the liquid receiving region Q and suppress moisture, and can make the discoloration of the super absorbent polymer 67 less visible from the outside. From the same viewpoint, the overlapping portion of the position of the high grammage region 6H and the position of the colored portion preferably occupies 10% or more of the area of the high grammage region 6H.

In the present embodiment, as shown in fig. 6, the slit portion 8 is preferably disposed in the absorbent core 6. The slit 8 is a space portion formed in the absorbent core 6 in the thickness direction from the skin surface side, with the amount of the pulp fibers 68 being smaller than the periphery. The slit portion 8 may be a slit-shaped portion or a groove having a predetermined width. At the position where the slit part 8 is disposed, the excretory fluid easily permeates in the thickness direction of the absorbent core 6. That is, the excretory fluid easily reaches the thickness direction central portion 63 formed as the high density layer of the superabsorbent polymer. This can improve the liquid absorption and retention property and the moisture regain prevention property in the diaper 10. That is, the above-mentioned rapid improvement of the liquid absorption and retention property and the rewet resistance can be simultaneously achieved, and the discoloration of the super absorbent polymer 67 is less likely to become conspicuous by forming the thickness direction central portion 63 as a super absorbent polymer high density layer.

From the viewpoint of improving the liquid absorption and retention properties and the rewet resistance described above, the slit portion 8 preferably has a depth from the skin surface side of the absorbent core 6 to the thickness direction central portion 63, and more preferably a through hole from the skin surface side to the non-skin surface side of the absorbent core 6.

From the same viewpoint, the slit 8 is preferably present in the liquid receiving region Q of the absorbent core 6.

In fig. 6, the slit portion 8 has a length extending from the liquid receiving region Q to the front and rear in the longitudinal direction Y, and 3 slit portions are arranged side by side in the width direction X. The arrangement and number of the slits 8 are not limited to this, and the embodiment shown in fig. 6 is preferable from the viewpoint of improving the liquid absorption and retention properties and the moisture regain resistance.

When there are a plurality of slit portions 8, the widths (groove widths, lengths in the width direction X) of the slit portions 8 may be the same or different from each other. When the width of each slit 8 is the same, the excretory fluid is easily and uniformly and rapidly diffused in the absorbent core 6. This is more preferable because a wider area of the absorbent core 6 can be used for liquid absorption. From the viewpoint of making this effect more remarkable, the width of each slit portion 8 is preferably 1mm or more, and more preferably 3mm or more. The width of each slit portion 8 is preferably 20mm or less, and more preferably 15mm or less. Specifically, the width of each slit portion 8 is preferably 1mm or more and 20mm or less, and more preferably 3mm or more and 15mm or less. In addition, when the widths of the slit portions 8 are different from each other, the width of each slit portion 8 is preferably within the above range.

When there are a plurality of slits 8, the lengths (lengths in the longitudinal direction Y) of the slits 8 may be the same or different from each other. When the length of each slit portion 8 is the same, the excretory fluid is easily and quickly diffused in the absorbent core 6. This is more preferable because a wider area of the absorbent core 6 can be used for liquid absorption. From the viewpoint of making this effect more remarkable, the length of each slit portion 8 is preferably 50mm or more, and more preferably 100mm or more. The length of each slit portion 8 is preferably 350mm or less, and more preferably 300mm or less. Specifically, the length of each slit portion 8 is preferably 50mm or more and 350mm or less, and more preferably 100mm or more and 300mm or less. Even when the lengths of the slits 8 are different from each other, the lengths of the slits 8 are preferably within the above-described range.

When the lengths of the respective slit portions 8 are the same, the positions of the front F-side end portions T1 of the slit portions 8 may be the same or different. Similarly, the positions of the rear portion R side end portions T2 of the respective slit portions 8 may be the same as or different from each other. In fig. 6, the positions of the front F side end portions T1 of the respective slit portions 8 are the same, and the positions of the rear R side end portions T2 of the respective slit portions 8 are the same.

Each slit portion 8 is preferably absent in the rear portion R. The end T2 of each slit 8 on the rear R side is preferably located on the front F side with respect to the boundary T3 between the low grammage range 6L and the high grammage range 6H. This makes it possible to balance the liquid absorption capacity of the absorbent core 6, the liquid diffusibility in the absorbent core 6, and the favorable wearing feeling of the diaper 10. In particular, the distance between the end T2 of each slit portion 8 on the rear portion R side and the boundary position T3 between the low grammage region 6L and the high grammage region 6H is preferably 5mm or more, and more preferably 10mm or more. Further, it is preferably 50mm or less, more preferably 45mm or less. Specifically, the distance between the end T2 on the rear portion R side of each slit portion 8 and the boundary position T3 between the low grammage region 6L and the high grammage region 6H is preferably 5mm or more and 50mm or less, and more preferably 10mm or more and 45mm or less. This makes it easier for the liquid in the high grammage region 6H to spread. Further, the absorbent core 6 is easily deformed by bending, and the wearing feeling of the diaper 10 becomes more favorable.

In particular, if the respective slit portions 8 are not present on the rear portion R side of the absorbent core 6 at positions corresponding to the fecal excretion portion of the wearer, the excreted feces are less likely to adhere to the skin of the wearer, which is preferable. The term "not present" on the rear portion R side means that the end T2 on the rear portion R side of all the slits 8 is located on the front side F with respect to the position corresponding to the fecal excretion portion of the wearer.

The slit 8 can be produced by providing an air-impermeable convex portion in a portion to be the slit 8 in the collecting concave portion disposed on the outer peripheral surface of the rotary drum, in addition to the method of cutting the absorbent core 6.

In addition, the colored portion is preferably positioned to overlap with the slit portion 8 in a plan view. In the space of the slit portion 8, the super absorbent polymer 67 in the absorbent core 6 is generally likely to fall off (or leak). In particular, in the diaper 10, the central portion 63 in the thickness direction of the absorbent core 6 is formed as a high-density layer of a highly absorbent polymer, and therefore, the dropping is likely to occur. On the other hand, since the position of the slit portion 8 and the position of the colored portion overlap in a plan view, the superabsorbent polymer 67 dropped into the slit portion 8 is not easily visible from the outside of the diaper 10 even if it is discolored. That is, the effect of making the discoloration of the super absorbent polymer 67 less visible from the outside of the diaper 10 and the effect of improving the absorption performance can be further improved by the super absorbent polymer high-density layer in the thickness direction central portion 63, the slit portion 8, and the colored portion.

In particular, from the viewpoint of making the discolored super absorbent polymer 67 less visible more effectively, the colored portion of the member other than the skin surface side of the absorbent core 6 (for example, the back sheet 4) is preferably formed as a whole-surface coated portion of the coloring agent, and the position of the colored portion is preferably overlapped with the position of the slit portion 8 of the absorbent core 6 in a plan view.

The slit portion 8 is preferably a through-hole, since the introduction of the excretory fluid is improved. In this case, as shown in fig. 7, it is preferable that the core-covering sheets 7 covering the outer periphery of the absorbent core 6 are joined to each other (the skin-side core-covering sheet 71 and the non-skin-side core-covering sheet 72) at the position of the slit 8 between the skin-side and non-skin-side core-covering sheets 7 disposed on the absorbent core 6. That is, the skin-side covering sheet 71 and the non-skin-side covering sheet 72 are preferably joined by entering the slit portion 8 from both sides of the absorbent core 6. The joint is more preferably formed so as not to peel off even if wetted with the excretory fluid. This makes it difficult for the super absorbent polymer 67 to move to the position of the slit in the absorbent body 5, and the discolored super absorbent polymer 67 is not easily visible from the outside. Further, the joining of the

core pieces

71, 72 to each other can be performed by various methods for achieving the above-described effects.

The core-wrapped sheet 7 covers the entire length direction Y of the absorbent core 6 as described above, extends in the width direction X, and is wound so as to cover the outer periphery of the absorbent core 6. The ends of the wound core-spun sheet 7 are laminated to each other. The laminated portion 75, which is a portion where the core sheets 7 are laminated with each other, has a relatively large sheet thickness due to the lamination, and discoloration of the super absorbent polymer 67 in the absorbent core 6 is less likely to be seen. From this viewpoint, it is preferable that the position where the superabsorbent polymer 67 is present in a large amount and the position of the portion (laminated portion 75) where the core sheets 7 are laminated overlap each other in a plan view. Here, the position where the superabsorbent polymer 67 is present in a large amount refers to a position that is either or both of the thickness direction center portion 63 and the high grammage region 6H in the planar direction of the superabsorbent polymer high-density layer.

From the viewpoint of suppressing the migration and the falling-off of the super absorbent polymer 67, the absorbent core 6 preferably has a compressed portion (not shown) formed by applying a certain amount of compression in the thickness direction by embossing or the like. The pulp fibers 68 are subjected to compression in the above-described compression section, whereby the movement of the super absorbent polymer 67 is easily restricted. As long as this effect is achieved, the depth of the compressed portion can be set appropriately, and may be a depth reaching the thickness direction central portion 63 of the absorbent core 6. From the viewpoint of preventing the absorption of the super absorbent polymer 67 from being hindered by compression, the compressed portion is preferably set so that the depth thereof does not reach the thickness direction center portion 63 but ends in the range of either the front surface portion 61 or the back surface portion 62. In addition, from the viewpoint of preventing the softness of the absorbent core 6 from being reduced, it is preferable that the compressed portion is present only in the front portion 61. The compressed portion can be formed in a linear shape in the planar direction of the absorbent core 5 on the skin surface side with respect to the absorbent core 5 including the absorbent core 6 and the core sheet 7, for example. The linear compressing units may be, for example, lattice-shaped compressing units arranged obliquely with respect to the longitudinal direction Y and the width direction X. The shape of the compressed part is not particularly limited as long as the above-described function can be achieved, and the inclined lattice shape may be a staggered shape or a corrugated shape. The compressed portion is not limited to being provided only in the absorbent body 5, and may be configured to compress the absorbent body 5 and the topsheet 3 integrally, for example.

Next, each component will be described.

(absorber 5)

As the liquid-retentive absorbent member 5, any absorbent member generally used in various absorbent articles such as diapers can be used without any particular limitation as long as the effects of the present invention can be obtained.

The absorbent body 5 preferably contains synthetic fibers. Specific examples of the synthetic fibers include polypropylene fibers, polyethylene fibers, and polyester fibers. Of the absorbent core 6 and the core-wrapped sheet 7 constituting the absorbent body 5, at least the absorbent core 6 preferably contains synthetic fibers, and more preferably both the absorbent core 6 and the core-wrapped sheet 7 contain synthetic fibers. The absorbent body 5 contains synthetic fibers, and is not easily deformed even when exposed to excretory fluid. As a result, the discolored super absorbent polymer 67 can be prevented from being seen through the gaps of the deformed absorbent body 5.

In the absorbent core 6, the surface area of the super absorbent polymer 67 is preferably larger toward the skin surface side. The superabsorbent polymer 67, if it has a large surface area, tends to look whiter due to the diffuse reflection of light. Thus, even if the superabsorbent polymer 67 in the vicinity of the skin surface side discolors, the diaper 10 can be easily made to look whiter when viewed from the skin surface side.

In addition, the absorber 5 may have an antioxidant. Specific examples of the antioxidant include hindered phenol antioxidants such as triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate ], 1, 6-hexanediol-bis [3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ], octadecyl-3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate and diethyl 3, 5-di-t-butyl-4-hydroxybenzylphosphonate, and amine antioxidants such as n-butyl amine, triethylamine and diethylaminomethyl methacrylate. The antioxidant may be contained in either one of the absorbent core 6 and the core-covering sheet 7 constituting the absorbent body 5, or may be contained in both of them. For example, the synthetic fibers in the absorbent body may be contained, or the hot melt adhesive may be contained. However, the antioxidant may be contained in the super absorbent polymer or may not be contained in the super absorbent polymer. Thus, even when a high-priced super absorbent polymer containing a component for suppressing discoloration is not used, that is, a normal super absorbent polymer is used, discoloration of the super absorbent polymer is suppressed in addition to the above-described effect by the structure of the absorbent core 6, and discoloration is less likely to be conspicuous from the outside of the diaper 10 even if discoloration occurs.

(front sheet 3)

The topsheet 3 is liquid-permeable, and sheets generally used in various absorbent articles such as diapers can be used without particular limitation. From the viewpoint of allowing excreted body fluid to rapidly pass through and move to the absorbent body and the viewpoint of improving the skin feel, hydrophilic heat-bonded nonwoven fabrics are preferable, and particularly, hot-air nonwoven fabrics are preferable. Preferably, the thermoplastic resin fibers are hydrophilized and the fibers are crimped with 2 or 3 crimps. Specifically, polyethylene, polypropylene, polyester, nylon, and composite fibers thereof are produced, and various hydrophilizing agents are applied to the fibers at a stage before the fibers are cut into a predetermined length to form short fibers. Hydrophilization treatment by a hydrophilizing agent known to those skilled in the art can be used, and examples of the hydrophilizing agent include various alkylsulfonic acid salts typified by α -olefin sulfonate, acrylic acid salts, acrylic acid salt/acrylamide copolymers, ester amides, salts of ester amides, polyethylene glycol and derivatives thereof, water-soluble polyester resins, various silicone derivatives, various saccharide derivatives, and mixtures thereof.

The front sheet 3 preferably has a concavo-convex configuration. When the topsheet 3 having the uneven structure is disposed on the skin surface side of the absorber, diffuse reflection of light is likely to occur on the skin surface side of the topsheet 3, and the diaper 10 is likely to look white when viewed from the skin surface side. As a result, the discolored super absorbent polymer 67 is not easily visible from the outside.

The fibers constituting the front sheet 3 preferably contain a color modifier. The color-changing agent is a component having an action of reducing and scattering the transmittance of light incident on the front surface sheet 3. When the color-changing agent is contained in the constituent fibers of the topsheet 3, the discolored super absorbent polymer 67 is not easily visible from the skin surface side.

Specific examples of the color-tone modifying agent include inorganic powder and organic powder having a refractive index different from that of the fiber-constituting component of the topsheet 3.

Examples of the inorganic powder include titanium oxide, porous silica (silica), porous silica, alumina (alumina), lime, and clay minerals. Examples of the clay mineral include montmorillonite, bentonite, kaolin, sericite, illite, glauconite, chlorite, zeolite, talc, and Mizukanite (zinc oxide-supported aluminosilicate).

Examples of the organic powder include polyethylene powder, polyester powder, polypropylene powder, polyacrylic acid powder, polyacrylate powder, cellulose powder, viscose powder, silk powder, organosilicon compound powder, and fluorine compound powder. Further, there may be mentioned a powder obtained by coloring these organic powders with a coloring agent. Among these, titanium oxide is preferably used as the color tone changing agent.

The content of the color modifier is preferably 0.1% by mass or more, more preferably 1% by mass or more, and still more preferably 3% by mass or more, based on 100% by mass of the entire fibers constituting the topsheet 3. By containing a certain amount or more of titanium oxide in the constituent fibers of the front sheet 3, light can be effectively scattered. On the other hand, the upper limit of the content of titanium oxide contained in the constituent fibers of the top sheet 3 is not particularly limited as long as the effects of the present invention can be obtained, and is actually 10 mass% or less.

(Back sheet 4)

The back sheet 4 may be a moisture-permeable film alone, a composite sheet in which a film and a nonwoven fabric are laminated, or a water-repellent nonwoven fabric (SMS, SMMS, or the like). From the viewpoint of cost, matching with an anti-slip adhesive, or the like, it is preferable to use the moisture permeable film alone as a leakage preventing material. The film material in this case includes a film obtained by melt-kneading and extruding a thermoplastic resin and an inorganic filler incompatible therewith, and the film is stretched to a predetermined size and is finely perforated, or a non-porous film which is substantially compatible with moisture and can discharge water vapor, such as a permeable film.

The colored portion is preferably disposed on the back sheet 4. The position of the colored section is preferably a position overlapping a position where the high absorbent polymer 67 is present in a large amount in the absorbent core 6 in a plan view of the absorbent core 6. In particular, if a lovely character such as a rabbit or cat is printed on the back sheet 4 as the colored portion, the discoloration of the super absorbent polymer 67 is likely to be inconspicuous from the back sheet 4 side, and the appeal of the diaper 10 to a wearer is improved.

(intermediate sheet)

The absorbent main body 1 constituting the diaper 10 preferably has an intermediate sheet (not shown) in addition to the front sheet 3, the back sheet 4, and the absorbent body 5. The absorbent core 6 is covered with the intermediate sheet in addition to the topsheet 3 and the core sheet 7, and the discolored super absorbent polymer 67 in the absorbent core 6 can be made less visible.

Various materials commonly used for such articles can be used for the outer covering body 2 and the side sheets 9 constituting the diaper 10, the elastic members disposed thereon, and the outer-covering nonwoven fabric 48.

As described above, in the diaper 10 of the present embodiment, since the discoloration of the super absorbent polymer 67 is less likely to be seen from the outside, a good appearance can be maintained without using a super absorbent polymer containing a component for suppressing discoloration.

The diaper 10 of the present embodiment is shown as a pants-type diaper, but is not limited thereto, and may be a belt-type diaper. In the diaper 10 of the present embodiment, the outer package is separated into the front side and the rear side, but the present invention is not limited thereto, and various shapes can be adopted. For example, the outer covering is formed in a shape covering the entire front side portion 10F, the intermediate portion 10C, and the rear side portion 10R of the diaper 10, and is narrowed in the width direction at the intermediate portion 10C of the diaper 10. The shape of the absorbent core 6 is not limited to the shape of the present embodiment, and various shapes can be adopted. For example, the planar shape of the absorbent core 6 may be a shape that narrows in the width direction X at the intermediate portion C.

The absorbent article of the present invention is a concept of an absorbent article including a panty liner (panty liner), an incontinence pad, a sanitary napkin, a urine collection pad, and the like, in addition to the diaper of the above embodiment. In addition, in the above structure, other components may be assembled in accordance with the use and function.

The present invention further discloses the following absorbent article according to the above embodiment.

<1>

An absorbent article having an absorbent body including an absorbent core and a core-wrapped sheet covering the outer periphery of the absorbent core, wherein in the absorbent article,

the absorbent core is formed of an aggregate of a super absorbent polymer and pulp fibers,

the absorbent core is divided in the thickness direction into a front portion located on the skin surface side, a back portion located on the non-skin surface side, and a thickness direction central portion located between the front portion and the back portion,

the thickness direction central portion is formed as a high-absorbent polymer high-density layer having a mass ratio of the high-absorbent polymer to the pulp fibers larger than that of the front portion and the back portion.

<2>

The absorbent article according to the above <1>, wherein,

the mass ratio is 1.0 to 2.0 in the thickness direction central portion, and 0.25 to 0.75 in the front surface portion and the back surface portion.

<3>

The absorbent article according to the above <2>, wherein,

the mass ratio is preferably 1.25 or more, and more preferably 1.5 or more in the thickness direction central portion. Further, it is preferably 1.8 or less, and more preferably 1.6 or less.

<4>

The absorbent article according to the above <2> or <3>, wherein,

the mass ratio is preferably 0.38 or more, more preferably 0.4 or more, and is preferably 0.63 or less, more preferably 0.5 or less, in the front surface portion and the rear surface portion.

<5>

The absorbent article according to any one of the above <1> to <4>, wherein,

the mass ratio of the superabsorbent polymer to the pulp fibers in the thickness direction central portion is 1.3 times or more and 8 times or less, preferably 2.0 times or more, more preferably 3.0 times or more, further preferably 5 times or less, and further preferably 4 times or less, with respect to the mass ratio of the superabsorbent polymer to the pulp fibers in the front surface portion and the back surface portion.

<6>

The absorbent article according to any one of the above <1> to <5>, wherein,

a member having a colored portion is disposed on at least one of the skin surface side and the non-skin surface side of the absorbent core.

<7>

The absorbent article according to the above <6>, wherein,

the colored portion colors a region of 10% or more of the area of the member having the colored portion.

<8>

The absorbent article according to the above <6> or <7>, wherein,

the colored portion is darker in color than the color of the discolored super absorbent polymer.

<9>

The absorbent article according to any one of the above <6> to <8>, wherein,

the color of the colored portion is complementary to the color of the discolored super absorbent polymer.

<10>

The absorbent article according to any one of the above <6> to <9>, wherein,

the colored portion is green, blue or purple.

<11>

The absorbent article according to any one of the above <1> to <10>, wherein,

a high grammage region and a low grammage region having a lower grammage than the high grammage region are arranged in a plan view of the absorbent core,

when the plane area of the absorbent core is divided into a front part, an intermediate part including a liquid receiving area, and a rear part in the longitudinal direction, the high grammage area includes at least the liquid receiving area of the intermediate part, and the low grammage area includes at least the rear part.

<12>

The absorbent article according to the above <11>, wherein,

the grammage of the high grammage region is 120% or more and 250% or less, preferably 140% or more, and more preferably 230% or less, relative to the grammage of the low grammage region.

<13>

The absorbent article according to the above <12>, wherein,

the gram weight of the high gram weight region is 150g/m ² Above and 900g/m ² Hereinafter, it is preferably 200g/m ² More preferably 250g/m or more ² Above, 850g/m is further preferable ² Hereinafter, more preferably 800g/m ² The following.

<14>

The absorbent article according to the above <12> or <13>, wherein,

the gram weight of the low gram weight region is 100g/m ² Above and 600g/m ² Hereinafter, it is preferably 150g/m ² Above, more preferably 200g/m ² Above, 550g/m is further preferable ² Hereinafter, it is more preferably 500g/m ² The following.

<15>

The absorbent article according to any one of the above <11> to <14>, wherein,

the length of the high grammage region in the longitudinal direction of the absorbent core is 50% to 90%, preferably 60% or more, more preferably 70% or more, further preferably 85% or less, and further preferably 80% or less of the entire length of the absorbent core.

<16>

The absorbent article according to any one of the above <11> to <15>, wherein,

the length of the low grammage region in the longitudinal direction of the absorbent core is 10% or more and 50% or less, preferably 15% or more, more preferably 20% or more, further preferably 40% or less, more preferably 30% or less of the entire length of the absorbent core.

<17>

The absorbent article according to any one of the above <11> to <16>, wherein,

a member having the coloring part according to any one of the above <6> to <10> is disposed on the non-skin surface side of the absorbent core,

the high grammage region overlaps with the position of the colored portion in a plan view of the absorbent core.

<18>

The absorbent article according to the above <17>, wherein,

the overlapping part of the position of the high gram weight region and the position of the coloring part accounts for more than 10% of the area of the high gram weight region

<19>

The absorbent article according to any one of the above <6> to <18>, wherein,

the position of the colored section overlaps with the position of the end section in the longitudinal direction of the absorbent core in a plan view.

<20>

The absorbent article according to any one of the above <6> to <19>, wherein,

the absorbent core is provided with a slit portion, and the position of the slit portion and the position of the colored portion overlap in a plan view.

<21>

The absorbent article according to the above <20>, wherein,

the core-covering sheets disposed on the skin surface side and the non-skin surface side of the absorbent core are joined to each other at the position of the slit.

<22>

The absorbent article according to the above <20> or <21>, wherein,

the width of the slit portion is 1mm or more and 20mm or less, preferably 3mm or more, and preferably 15mm or less.

<23>

The absorbent article according to any one of the above <20> to <22>, wherein,

the length of the slit portion is 50mm or more and 350mm or less, preferably 100mm or more, and preferably 300mm or less.

<24>

The absorbent article according to any one of the above <20> to <23>, wherein,

the distance between the rear end of the slit and the boundary between the low grammage region and the high grammage region is 5mm or more and 50mm or less, more preferably 10mm or more, and still more preferably 45mm or less.

<25>

The absorbent article according to any one of the above <1> to <24>, wherein,

the absorbent body has a compressed portion.

<26>

The absorbent article according to any one of the above <1> to <25>, wherein,

the absorbent body has a portion where the core sheets are laminated,

the position where the superabsorbent polymer is present in a large amount overlaps with the position of the portion where the core-spun sheets are laminated in a plan view.

<27>

The absorbent article according to any one of the above <1> to <26>, wherein,

the absorbent body has synthetic fibers.

<28>

The absorbent article according to any one of the above <1> to <27>, wherein,

in the absorbent core, the surface area of the super absorbent polymer is increased toward the skin surface side.

<29>

The absorbent article according to any one of the above <1> to <28>, wherein,

a front sheet having an uneven structure is disposed on the skin surface side of the absorbent body.

<30>

The absorbent article according to any one of the above <1> to <29>, wherein,

the color-changing agent is contained in an amount of 0.1 mass% or more, preferably 1 mass% or more, more preferably 3 mass% or more, and preferably 10 mass% or less, based on 100 mass% of the entire constituent fibers of the front sheet.

<31>

The absorbent article according to any one of the above <1> to <30>, wherein,

an intermediate sheet is disposed between the absorbent body and the topsheet.

<32>

The absorbent article according to any one of the above <1> to <31>, wherein,

the absorber has an antioxidant.

The invention has been described in connection with embodiments and examples thereof, and it is not intended to be limited to any of the details described, unless otherwise specified, and it is to be understood that such is to be interpreted as broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

Priority is claimed by Japanese patent application 2019-122079, filed in Japan on 28.6.2019, the contents of which are incorporated herein by reference as part of the description of the present specification.

Description of reference numerals

1. Absorbent body

11. Side seal

12. Waist opening part

13. Leg opening part

2. Exterior body

21. Front side outer package body

22. Rear side outer body

3. Dough sheet

4. Back sheet

5. Absorbent body

6. Absorbent core

61. Front face part

62. Back face part

63. Thickness direction center portion (high-density layer of high-absorbency polymer)

67. Superabsorbent polymers

68. Pulp fiber

6H high grammage region

6L low grammage region

6E end in the longitudinal direction

7. Core-wrapped tablet

71. Skin surface side core-covering sheet

72. Non-skin side core-covering sheet

75. Lamination of core-clad sheets

8. Gap part

9. Side panel

91. Elastic component

92. Three-dimensional wrinkle part

93. Elastic component

94. Leg wrinkle part

10. Diaper with a disposable absorbent article

Front side part of 10F diaper

Middle part of 10C diaper

Rear side portion of 10R diaper

Waistline part of 10D diaper

Front side part of F absorbent core

C intermediate section of absorbent core

R rear side part of absorbent core

Y longitudinal direction of absorbent core (or longitudinal direction of absorbent body)

X width direction of absorbent core (or width direction of absorbent body)

Claims

1. An absorbent article having an absorbent body including an absorbent core and a core-spun sheet covering an outer periphery of the absorbent core, the absorbent article being characterized in that:

the absorbent core is divided in the thickness direction into a front part located on the skin surface side, a back part located on the non-skin surface side, and a thickness direction central part located between the front part and the back part,

the thickness direction central portion is formed as a high-absorbent polymer high-density layer in which the mass ratio of the high-absorbent polymer to the pulp fibers is larger than that of the front portion and the back portion,

a member having a colored portion is disposed on at least one of a skin surface side and a non-skin surface side of the absorbent core,

the colored portion has a color darker than that of the discolored superabsorbent polymer.

2. The absorbent article of claim 1, wherein:

the mass ratio is 1.0 or more and 2.0 or less in the thickness direction central portion, and 0.25 or more and 0.75 or less in the front surface portion and the back surface portion.

3. The absorbent article of claim 2, wherein:

the mass ratio is 1.25 or more and 1.8 or less in the thickness direction central portion.

4. The absorbent article of claim 2, wherein:

the mass ratio is 0.38 or more and 0.63 or less in the front surface portion and the rear surface portion.

5. The absorbent article according to any one of claims 1 to 4, wherein:

the mass ratio of the superabsorbent polymer to the pulp fibers in the thickness direction central portion is 1.3 times or more and 8 times or less with respect to the mass ratio of the superabsorbent polymer to the pulp fibers in the front surface portion and the back surface portion.

6. The absorbent article according to any one of claims 1 to 4, wherein:

7. The absorbent article according to any one of claims 1 to 4, wherein:

the colored portion has a color complementary to the color of the discolored super absorbent polymer.

8. The absorbent article according to any one of claims 1 to 4, wherein:

the color of the coloring part is green, blue or purple.

9. The absorbent article according to any one of claims 1 to 4, wherein:

10. The absorbent article of claim 9, wherein:

the grammage of the high grammage region is 120% or more and 250% or less with respect to the grammage of the low grammage region.

11. The absorbent article of claim 10, wherein:

the gram weight of the high gram weight area is 150g/m ² Above and 900g/m ² The following.

12. The absorbent article of claim 10, wherein:

the gram weight of the low gram weight area is 100g/m ² Above and 600g/m ² The following.

13. The absorbent article of claim 9, wherein:

the length of the high grammage region in the longitudinal direction of the absorbent core is 50% or more and 90% or less of the entire length of the absorbent core.

14. The absorbent article of claim 9, wherein:

the length of the low grammage region in the longitudinal direction of the absorbent core is 10% or more and 50% or less of the entire length of the absorbent core.

15. The absorbent article of claim 9, wherein:

a member having the colored portion is disposed on the non-skin surface side of the absorbent core,

the high grammage region overlaps with a position of the colored portion in a plan view of the absorbent core.

16. The absorbent article of claim 15, wherein:

an overlapping portion of a position of the high grammage region and a position of the colored portion occupies 10% or more of an area of the high grammage region.

17. The absorbent article according to any one of claims 1 to 4, wherein:

18. The absorbent article of claim 9, wherein:

19. The absorbent article of claim 18, wherein:

the core-covering sheets disposed on the skin surface side and the non-skin surface side of the absorbent core are joined to each other at the position of the slit portion.

20. The absorbent article of claim 18, wherein:

the width of the slit part is more than 1mm and less than 20 mm.

21. The absorbent article of claim 18, wherein:

the length of the slit part is 50mm to 350 mm.

22. The absorbent article of claim 18, wherein:

the distance between the end on the rear side of the slit and the boundary position between the low grammage region and the high grammage region is 5mm to 50 mm.

23. The absorbent article according to any one of claims 1 to 4, wherein:

the absorbent body has a compressed portion.

24. The absorbent article according to any one of claims 1 to 4, wherein:

the absorbent body has a portion where the core sheets are laminated with each other,

25. The absorbent article according to any one of claims 1 to 4, wherein:

the absorbent body has synthetic fibers.

26. The absorbent article according to any one of claims 1 to 4, wherein:

in the absorbent core, the surface area of the super absorbent polymer increases toward the skin surface side.

27. The absorbent article according to any one of claims 1 to 4, wherein:

28. The absorbent article of claim 27, wherein:

the color-changing agent is contained in an amount of 0.1 to 10 mass% based on 100 mass% of the entire fibers constituting the front sheet.

29. The absorbent article of claim 27, wherein:

an intermediate sheet is disposed between the absorbent body and the topsheet.

30. The absorbent article according to any one of claims 1 to 4, wherein:

the absorber has an antioxidant.