JP7623801B2 - Sheet for absorbent article and absorbent article using same - Google Patents

Description

The present invention relates to a sheet for absorbent articles and an absorbent article using the same.

In absorbent articles such as disposable diapers, a multi-layered nonwoven fabric is used on the skin-facing side of the absorbent article to absorb liquid excreted by the wearer and improve comfort. The applicant has proposed an absorbent article with a surface material consisting of a layer formed of a nonwoven fabric containing a thermoplastic resin and a layer formed of an absorbent sheet containing at least cellulose fibers, with the aim of reducing residual liquid on the surface (see Patent Document 1).

The applicant also proposed an absorbent article with a back waist flap in which a hydrophobic skin-side sheet that forms the skin-contacting surface and a hydrophilic non-skin-side sheet located on the non-skin-facing side of the skin-side sheet are joined at multiple joints, with the aim of quickly transferring absorbed sweat to the non-skin-facing side (see Patent Document 2).

Patent document 3 also discloses a disposable diaper that has a sweat-absorbent sheet consisting of an inner layer on the side that contacts the skin and an outer layer on the opposite side, where the inner layer is formed by mixing hydrophobic fibers and hydrophilic fibers, and the outer layer is formed containing 50 to 100% by weight of hydrophilic fibers.

Japanese Patent Application Publication No. 8-66425 JP 2017-113188 A JP 2001-327534 A

The absorbent articles described in Patent Documents 1 and 2 are designed to quickly transfer absorbed liquid to the non-skin facing side, making it difficult for bodily fluids to remain on the wearer's skin, but there is room for improvement in terms of further reducing the amount of liquid remaining on the skin. Furthermore, it cannot be said that the absorbent article described in Patent Document 3 has sufficiently achieved a reduction in the amount of liquid remaining on the skin.

Therefore, the present invention aims to provide a sheet for absorbent articles that prevents bodily fluids from remaining on the wearer's skin.

The present invention provides a textile fabric comprising a first surface, the first surface comprising a first fibrous layer comprising synthetic fibers;
a second fibrous layer including cellulose fibers and including a second surface opposite to the first surface;
the first fibrous layer comprises fibers having a contact angle with water of less than 90°;
An embossed portion is formed in the first fiber layer,
a concave-convex shape having a plurality of concave portions formed by the embossed portion and convex portions formed between the concave portions is formed on the first surface,
The present invention provides a sheet for absorbent articles, in which the second fibrous layer has a Klemm water absorption height of 4 cm or more as measured in accordance with JIS P8141.

The present invention also provides a sheet for absorbent articles,
The present invention provides an absorbent article using the sheet as a top sheet or a sweat-absorbing sheet.

The present invention provides a sheet for absorbent articles that prevents excreted body fluids from remaining on the wearer's skin.

1(a) and (b) are perspective views each showing a schematic diagram of an embodiment of a sheet for absorbent articles of the present invention in a no-load state. 2(a) and (b) are cross-sectional views that diagrammatically show an embodiment of the cross section taken along line II in FIG. 1(b).

The present invention will be described below based on preferred embodiments with reference to the drawings. The absorbent article sheet 1 shown in Figs. 1 and 2 (hereinafter, simply referred to as "sheet 1") is suitable for use as a component of an absorbent article that absorbs excreted body fluids such as urine, sweat, and menstrual blood.

1 and 2 show a schematic diagram of an embodiment of the sheet 1 in an unloaded state. The sheet 1 has a first surface F and a second surface R, which is the surface opposite to the first surface F. When the sheet 1 is used as a component of an absorbent article, the first surface F is preferably arranged on the skin-contacting surface side, which is the surface that contacts the skin of the wearer, and the second surface R is preferably arranged on the non-skin-contacting surface side, which is the surface opposite to the skin-contacting surface. The sheet 1 is a multi-layered sheet in which a first fiber layer 11 including the first surface F and a second fiber layer 12 including the second surface R are integrated. In the embodiment shown in FIG. 1 and FIG. 2, the sheet has a two-layered structure in which the fiber layers 11 and 12 are arranged adjacent to each other. Details of the fibers contained in the fiber layers 11 and 12 will be described later.

The sheet 1 has an embossed portion 15 formed at least in the first fiber layer 11, and preferably the first fiber layer 11 and the second fiber layer 12 are joined by the embossed portion 15. The embossed portion 15 is a portion where the fiber layer is compressed in the thickness direction, the fibers are not fused to each other, and the density of the fibers is higher than in the portion other than the embossed portion 15, or the fibers are fused to each other. By forming the embossed portion 15 at least in the first fiber layer 11, an uneven shape having a plurality of recesses 17 made of the embossed portion 15 and protrusions 18 formed between the recesses 17 is formed on one side of the first surface F of the sheet 1. In other words, the recesses 17 are formed in correspondence with the portions where the embossed portion 15 is formed, and a plurality of protrusions 18 are formed in the portions where the embossed portion 15 is not formed. In particular, the embossed portion 15 joins the first fiber layer 11 and the second fiber layer 12, which makes it easier for bodily fluids to migrate to the second fiber layer through the embossed portion, where the fiber density is high, and reduces the amount of fluid remaining on the first fiber layer. In addition, while achieving the above-mentioned effects, the sheet 1 has the advantage of being easily manufactured with high efficiency and having sheet strength that can withstand use.

The form of the embossed portion 15 formed on the sheet 1 may be, for example, as shown in FIG. 1(a), configured by continuous straight lines inclined in opposite directions to each other with respect to the X direction when the sheet 1 is viewed in a plane. In the form of the embossed portion 15 shown in FIG. 1(a), when the sheet 1 is viewed in a plane, the first embossed portion line 15A formed by a continuous straight line and the second embossed portion line 15B formed by a continuous straight line are formed to be inclined in opposite directions to each other with respect to the X direction. The first embossed portion line 15A and the second embossed portion line 15B shown in the figure are each formed in a large number parallel to each other. In addition, the intervals between the adjacent first embossed portion lines 15A and the intervals between the adjacent second embossed portion lines 15B are approximately the same. The positions where the first embossed portion line 15A and the second embossed portion line 15B are formed are the positions of the recesses 17 on the first surface F. In addition, the area defined by the two first embossed lines 15A and the two second embossed lines 15B is the position of the convex portion 18 on the first surface F.

As another embodiment of the embossed portion 15 formed on the sheet 1, for example, as shown in FIG. 1(b), when the sheet 1 is viewed in plan, the embossed portion 15 may be formed in a scattered dot pattern in the sheet surface direction. In the embodiment of the embossed portion 15 shown in FIG. 1(b), when the sheet 1 is viewed in plan, a plurality of circular embossed portions 15 are formed at a predetermined interval. The embossed portion 15 shown in the figure constitutes a plurality of embossed portion rows 15C extending in a direction perpendicular to the X direction, and the pitches of the adjacent embossed portion rows 15C are the same and the phases are shifted by half a pitch. Alternatively, the pitches of the adjacent embossed portion rows 15C may be different. In addition, the phase shift of each adjacent embossed portion row 15C may be periodic or non-periodic.

The planar shape of the embossed portions 15 formed in a scattered pattern may be a circle as shown in FIG. 1(b), a polygon such as a rectangle or a hexagon, an alphabet shape such as an X-shape or a Y-shape, a lattice shape, or a combination of these. The position where the embossed portion 15 is formed is the position of the recessed portion 17 on the first surface F. The area surrounded by four embossed portions 15 is the position of the protruding portion 18 on the first surface F. Of the above-mentioned formation modes of the embossed portions 15, it is preferable that the embossed portions 15 are formed in a scattered pattern in the sheet surface direction from the viewpoint of increasing the number of starting points where the attraction of bodily fluids occurs while increasing the flexibility of the sheet.

2(a) and (b) show schematic cross-sectional views of the sheet 1. The embossed portion 15 shown in the figure is formed so as to bond the first fiber layer 11 and the second fiber layer 12 together. The sheet 1 is formed by the embossed portion 15, and a plurality of recesses 17 recessed toward the second surface R side and a plurality of protrusions 18 protruding toward the first surface F side are formed on the first surface F. The recesses 17 are portions in which the sheet thickness is smaller than that of the protrusions 18. The heights of the recesses 17 and the protrusions 18 may be the same or different. On the other hand, the second surface R of the sheet 1 has a flat shape. Alternatively, the second surface may have a concave and convex shape in which a plurality of recesses and protrusions are formed so as to match the positions of the recesses 17 and the protrusions 18 on the first surface F. The boundary surface between the fiber layers 11 and 12 at the protrusions 18 is preferably clear. In the embossed portion 15, there is no boundary between the fiber layers 11 and 12, or the boundary is unclear.

The protrusion 18 may have a solid structure in which the first fiber layer 11 and the second fiber layer 12 are in contact with each other, as shown in FIG. 2(a), or alternatively, may have a hollow structure in which the first fiber layer 11 and the second fiber layer 12 are spaced apart, with a space S defined by the lower surface of the first fiber layer 11 and the upper surface of the second fiber layer 12, as shown in FIG. 2(b).

2(a) and (b) of the sheet 1, the first fiber layer 11 is composed of a fiber aggregate mainly containing synthetic fiber 2. The second fiber layer 12 shown in the same figure is composed of a fiber aggregate mainly containing cellulose fiber 3. In this specification, "mainly" means that the mass ratio of the constituent fibers to the mass of one fiber layer is 50 mass% or more. Note that the synthetic fibers 2 and cellulose fibers 3 shown in Figures 2(a) and (b) are illustrated as having different fiber diameters, but this is only shown for the convenience of explaining the first fiber layer and the second fiber layer. The fiber diameters of both fibers may be the same, the fiber diameter of the cellulose fiber 3 may be larger than the fiber diameter of the synthetic fiber 2, and the fiber diameter of the synthetic fiber 2 may be larger than the fiber diameter of the cellulose fiber 3.

Examples of synthetic fibers contained in the first fiber layer 11 include fibers containing one or more thermoplastic resins such as polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyester resins such as polyethylene terephthalate (PET), polyamide resins, vinyl resins such as polyvinyl chloride and polystyrene, acrylic resins such as polyacrylic acid and polymethyl methacrylate, and fluororesins such as polyperfluoroethylene as polymeric components. If necessary, these fibers may be subjected to a hydrophilic or hydrophobic treatment on the fiber surface. These fibers may be used alone or in combination of two or more types.

When a thermoplastic fiber is used as the synthetic fiber, the fiber may or may not have heat shrinkability. An example of a thermoplastic fiber having heat shrinkability is a latent shrink fiber. A latent shrink fiber can be handled in the same way as a normal fiber before being heated, and has the property of shrinking by developing a spiral crimp when heated at a predetermined temperature. A latent shrink fiber is, for example, an eccentric core-sheath type or a side-by-side type composite fiber made of two types of thermoplastic resins with different shrinkage rates. Examples of such fibers include those described in JP-A-9-296325 and JP-A-2-191720.

Examples of cellulose fibers contained in the second fiber layer 12 include natural cellulose fibers such as cotton fibers and pulp fibers, regenerated cellulose fibers such as rayon, refined cellulose fibers such as lyocell fibers (Tencel (registered trademark) and Veocel (registered trademark)), and semi-synthetic cellulose fibers such as acetate fibers. These fibers can be used alone or in combination of two or more types.

As the fiber aggregates constituting the first fiber layer 11 and the second fiber layer 12, various fiber sheets such as paper, woven fabric, and nonwoven fabric containing the above-mentioned fibers can be used independently. When nonwoven fabric is used, various nonwoven fabrics such as air-through nonwoven fabric, air-laid nonwoven fabric, spunbond nonwoven fabric, spunlace nonwoven fabric, meltblown nonwoven fabric, and needle-punched nonwoven fabric can be used.

The fibers constituting the first fiber layer 11 also include fibers whose contact angle with water is less than 90°, preferably 70° or less, more preferably 50° or less, and in practice, 0° or more.

The contact angle of the fibers with water can be measured by the following method: The fibers located on the surface of the first side of the sheet 1 are carefully removed using tweezers and a razor or scissors so that the fibers have a length of 1 mm or more without pulling the fibers, and the contact angle of water with these fibers is measured.
As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. The contact angle is measured using distilled water in an environment of 22±2°C temperature and 60±5% RH. The amount of liquid discharged from the inkjet type water droplet discharge part (CTC-25 pulse injector with a discharge part diameter of 25 μm manufactured by Cluster Technology Co., Ltd.) is set to 10 picoliters, and the water droplets are dropped directly on the fiber. The dropping state is recorded on a high-speed recording device connected to a horizontally installed camera. From the viewpoint of later image analysis and image analysis, it is preferable that the recording device is a personal computer with a high-speed capture device built in. In this measurement, an image is recorded every 17 milliseconds (17 msec). In the recorded video, the first image of a water droplet landing on the fiber taken out of sheet 1 is analyzed using the attached software FAMAS (software version 2.6.2, analysis method: droplet method, analysis method: θ/2 method, image processing algorithm: non-reflective, image processing image mode: frame, threshold level: 200, no curvature correction), the angle between the surface of the water droplet in contact with the air and the fiber is calculated, and the angle between the water droplet and the fiber is taken as the contact angle. The fiber taken out of the first surface of the sheet is cut to a fiber length of 1 mm, and the fiber is placed on the sample stage of the contact angle meter and maintained horizontally. The contact angles at three different points for each fiber are measured to one decimal place, and the arithmetic average value (rounded off to two decimal places) is taken as the contact angle of the fiber.
This procedure is repeated for the 100 fibers constituting the first fiber layer to calculate the contact angle of each fiber. If at least one of the 100 fibers randomly taken from the surface of the first fiber layer has a contact angle of less than 90°, the first fiber layer 11 is determined to contain fibers with a contact angle with water of less than 90°. The smaller the contact angle with water, the higher the hydrophilicity of the fiber.

When the average fiber contact angle is the arithmetic mean of the contact angles of 100 fibers measured by the above-mentioned method, the average fiber contact angle of the first fiber layer 11 is preferably 100° or less, more preferably 90° or less, even more preferably 80° or less, and preferably 50° or more, more preferably 55° or more, even more preferably 60° or more. When the average fiber contact angle of the first fiber layer 11 is such a value, body fluids can easily adhere to the first fiber layer 11, and the body fluids can be transferred to the second fiber layer 12 without being retained in the first fiber layer 11.

In the above-mentioned measurement of the contact angle between the fiber and water, if it is difficult to obtain fibers with a fiber length of 1 mm, the sheet 1 is placed on a sample table, and water droplets are applied to the fibers in the measurement target surface of the sheet 1, where the surface of the sample table and the fiber surface are approximately parallel, by the above-mentioned method, to measure the contact angle of the fiber. In addition, if the sheet to be measured is incorporated in an absorbent article, a region including the sheet is cut out together with other components to obtain a test piece, and the sheet to be measured is carefully peeled off while blowing hot air onto the test piece using a dryer or the like to remove the influence of the adhesive, and this is the sample to be used in this measurement. This means is common to other measurements in this specification.
In addition, in measuring the contact angle between the fiber and water described above, if the fiber has high water absorption and water droplets that land on the fiber disappear in 17 milliseconds or less, making it difficult to measure the contact angle every 17 milliseconds, the contact angle between the fiber being measured and water is deemed to be 20°.

Regarding the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11 is preferably 0 cm or more, preferably 2 cm or less, and more preferably 1 cm or less. The higher the Klemm water absorption height, the higher the liquid diffusibility in the sheet surface direction and thickness direction. Therefore, this configuration makes it easier for bodily fluids to move from the first fiber layer 11 to the second fiber layer 12, making it less likely for bodily fluids to remain on the wearer's skin and on the first fiber layer 11 side.

As for the second fiber layer 12, the Klemm water absorption height C2 of the second fiber layer 12 is preferably 4 cm or more, more preferably 5 cm or more, and realistically 9 cm or less. This configuration facilitates the transfer of bodily fluids from the first fiber layer 11 to the second fiber layer 12, and makes it difficult for bodily fluids that have transferred to the second fiber layer 12 to return to the first fiber layer 11, and as a result, makes it difficult for bodily fluids to remain on the wearer's skin.

In terms of the relationship between the Klemm absorption heights of the fiber layers 11 and 12, it is preferable that the Klemm absorption height C1 of the first fiber layer 11 is lower than the Klemm absorption height C2 of the second fiber layer 12. In particular, the difference (C2-C1) between the Klemm absorption height C1 of the first fiber layer 11 and the Klemm absorption height C2 of the second fiber layer 12 is preferably 3 cm or more, more preferably 4 cm or more, and realistically 9 cm or less, on the condition that C2>C1. With this configuration, the second fiber layer 12 is more hydrophilic than the first fiber layer 11, which makes it easier for body fluids to migrate from the first fiber layer 11 to the second fiber layer 12 and makes it more difficult for body fluids that have migrated to the second fiber layer 12 to return to the first fiber layer 11.
In order to make the Klemm water absorption heights of the fiber layers 11 and 12 different from each other, the type of cellulose fiber contained in the first fiber layer and the type of cellulose fiber contained in the second fiber layer can be made different from each other. In this case, for example, at least one of regenerated cellulose fiber, refined cellulose fiber, and semi-synthetic cellulose fiber may be used as the cellulose fiber contained in the first fiber layer, and pulp fiber may be used as the cellulose fiber contained in the second fiber layer.
In order to make the Klemm absorbency heights of each fiber layer 11, 12 different from each other, the type of cellulose fiber contained in the first fiber layer and the type of cellulose fiber contained in the second fiber layer can be the same, and the proportion of cellulose fiber contained in the first fiber layer can be made lower than the proportion of cellulose fiber contained in the second fiber layer.

The above-mentioned Klemm water absorption height can be measured, for example, in accordance with JIS P8141.
In detail, first, the absorbent sheet to be measured is cut into a rectangular piece having a length of 10 cm in the fiber flow direction and a width of 3 cm in the direction perpendicular to the fiber flow direction to prepare a measurement piece. If the fiber flow direction cannot be determined visually, 10 or more fibers present on the sheet surface are observed using a microscope or scanning electron microscope, and the direction in which the extension direction of the fibers extends by 50% or more by number is determined to be the fiber flow direction.
The test piece is then fixed so that the longitudinal direction of the test piece is perpendicular to the planar direction, and in this state, the test piece is immersed for 3 minutes in ion-exchanged water colored with 0.1% by mass of blue dye (Blue No. 1, for example, manufactured by Hodogaya Chemical Co., Ltd.) dissolved therein. The height from the water surface (the height of the solvent tip, with a position 1 cm above the longitudinal lower end of the test piece as the reference point) is then measured at four points spaced 1 cm apart along the width direction of the test piece starting from one end in the width direction, and the arithmetic average value is taken as the Klemm water absorption height (cm) in the present invention.
When the Klemm water absorption height differs between one side and the other side of the test piece, the side of the test piece with the lower Klemm water absorption height is taken as the side facing the first fiber layer 11, and the Klemm water absorption height of this side is taken as the Klemm water absorption height C1 of the first fiber layer 11. Moreover, the side of the test piece with the higher Klemm water absorption height is taken as the side facing the second fiber layer 12, and the Klemm water absorption height of this side is taken as the Klemm water absorption height C2 of the second fiber layer 12.

In the absorbent article sheet having the above-mentioned configuration, the contact angle of the constituent fibers of the first fiber layer with water is less than a predetermined value, so that, for example, when the sheet is arranged so that its first surface constitutes the skin contact surface of the absorbent article, sweat adhering to the wearer's skin and body fluids excreted from the wearer can easily come into contact with the sheet surface. In addition, since the Klemm water absorption height of the second fiber layer is a predetermined value, the transfer of body fluids from the first fiber layer to the second fiber layer having a relatively high hydrophilicity, and further the transfer of body fluids to the side of the second fiber layer where the first fiber layer is not present, can be facilitated, and the body fluids drawn into the second fiber layer side can be made less likely to return to the first fiber layer side. As a result, the body fluids can be made less likely to remain on the wearer's skin. This effect is more remarkable when the Klemm water absorption height of the first fiber layer is further adopted as a predetermined value.
In addition, the formation of the embossed portion 15 on the sheet increases the density of the fibers in the embossed portion 15 and its surroundings, improving the capillary force, and thus making it easier to draw body fluids into the sheet from the embossed portion 15 as the absorption starting point. Furthermore, the uneven shape formed on the first surface of the sheet 1 reduces the contact area between the sheet and the wearer's skin compared to a case in which the uneven shape is not formed. As a result, body fluids are less likely to remain on the wearer's skin, and skin troubles such as eczema and rashes caused by the remaining body fluids on the skin and friction between the sheet and the wearer's skin can be reduced.

From the viewpoint of increasing the ability to draw bodily fluids into the sheet and reducing the amount of the drawn fluid returning to the first fiber layer 11, it is preferable that the embossed portion 15 of the first fiber layer 11 in the cross-sectional view of the sheet is formed on the second fiber layer side. Formed on the second fiber layer side means that when a virtual dividing line L1 is drawn that virtually divides the first fiber layer 11 equally in the thickness direction, the embossed portion 15 is positioned biased toward the second fiber layer side. Such a configuration can be formed, for example, by forming the embossed portion 15 so as to press the first fiber layer 11 toward the second fiber layer 12 side in a state in which the first fiber layer 11 and the second fiber layer 12 are laminated, or by pressing the first fiber layer 11 in the thickness direction in advance to form the embossed portion 15, and arranging the surface of the first fiber layer 11 on the side where the embossed portion 15 exists facing the second fiber layer 12.

A preferred embodiment of the constituent fibers in each of the fiber layers 11 and 12 will be described below.
The first fiber layer 11 preferably further contains cellulose fibers in addition to the synthetic fibers 2, and more preferably contains at least one of regenerated cellulose fibers, refined cellulose fibers, and semi-synthetic cellulose fibers as the cellulose fibers. The first fiber layer 11 is also preferably a nonwoven fabric made of a mixture of the synthetic fibers 2 and cellulose fibers. Since cellulose fibers are generally highly hydrophilic, by further containing cellulose fibers in the first fiber layer 11, the body fluids attached to or remaining on the wearer's skin can be efficiently transferred to the sheet side, and the remaining body fluids on the wearer's skin can be further reduced. In addition, by using regenerated cellulose fibers or refined cellulose fibers, there is an advantage that the manufacturing efficiency of the sheet 1 can be improved and the touch and texture of the obtained sheet can be improved. The cellulose fibers that can be contained in the first fiber layer 11 can be the above-mentioned ones. In addition, the cellulose fibers that can be contained in the first fiber layer 11 may be the same type as the cellulose fibers 3 contained in the second fiber layer 12, or may be different types.

The content of synthetic fibers in the first fiber layer 11 is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and preferably 100% by mass or less, more preferably 95% by mass or less, based on the total mass of the first fiber layer 11. In other words, the first fiber layer 11 may be formed only from synthetic fibers. In addition, when the first fiber layer 11 contains cellulose fibers, the content of cellulose fibers in the first fiber layer 11 is preferably 0% by mass or more, more preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

The determination of whether or not the first fiber layer 11 contains cellulose fibers and the amount of cellulose fibers can be determined by, for example, dyeing the sheet 1 with a fiber identification reagent (BOKENSTAIN II, manufactured by the Boken Quality Evaluation Organization, a general incorporated foundation) and observing the side or cross section of the sheet, and if fibers discolored blue are present in the first fiber layer 11, it can be determined that the first fiber layer 11 contains cellulose fibers. The amount of cellulose fibers in the first fiber layer 11 can be determined by taking out the first fiber layer 11 at any position, such as the convex portion 18 in the sheet 1, measuring the total mass of the first fiber layer 11, and then dyeing the constituent fibers of the first fiber layer 11 with the above-mentioned fiber identification reagent, and taking out only the fibers discolored blue. The discolored fibers are separated one by one and dried, and the total mass of the discolored fibers is measured, which is the mass of the cellulose fibers in the first fiber layer 11. In other words, the percentage of the content of the cellulose fibers relative to the total mass of the first fiber layer 11 is the content ratio of the cellulose fibers in the first fiber layer 11.

When the first fiber layer 11 contains cellulose fibers, the contact angle θ1 between the cellulose fibers contained in the first fiber layer 11 and water is preferably 0° or more, and preferably 60° or less, and more preferably 50° or less, from the viewpoint of promoting adhesion of body fluids such as sweat to the first fiber layer 11.

As for the second fiber layer 12, it is preferable that the cellulose fiber mainly contained in the second fiber layer 12 is pulp fiber, and it is also preferable that the second fiber layer 12 is paper. By configuring the second fiber layer 12 in this way, the high hydrophilicity and liquid retention of the pulp fiber can more efficiently transfer body fluids that come into contact with the first fiber layer to the second fiber layer, and the amount of body fluid remaining on the skin can be further reduced. Paper, which is a suitable form of the second fiber layer 12, is manufactured in accordance with the provisions of JIS P0001 by agglutinating plant fibers such as pulp fibers with other fibers such as synthetic fibers as necessary, and is preferably manufactured by a wet method.

In addition, it is preferable that the second fiber layer 12 further contains synthetic fibers in addition to the cellulose fibers 3. In this case, the synthetic fibers that can be contained in the second fiber layer 12 may be the same type as the synthetic fibers 2 contained in the first fiber layer 11, or may be a different type. In particular, when the second fiber layer 12 contains synthetic fibers, it is more preferable that the synthetic fibers contained in the first fiber layer and the synthetic fibers contained in the second fiber layer contain the same polymer components. With this configuration, it becomes easy to form the embossed portion that joins the first fiber layer 11 and the second fiber layer 12 by fusion, and the embossed portion 15 exhibits strong bonding properties, improving the strength of the sheet.

Whether the synthetic fibers contained in each fiber layer contain the same polymer component can be determined by the following method. First, the sheet 1 is dyed with the above-mentioned fiber identification reagent, and undyed fibers are taken from each side F and R of the sheet. The fibers taken from the first side F are the synthetic fibers contained in the first fiber layer 11, and the fibers taken from the second side R are the synthetic fibers contained in the second fiber layer 12. These synthetic fibers are measured using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.). A thermal analysis of a finely cut fiber sample (sample mass 1 mg) is performed at a heating rate of 10°C/min to measure the melting peak temperature (°C) of each fiber. When the melting peaks of the synthetic fibers contained in the first fiber layer 11 and the synthetic fibers contained in the second fiber layer 12 are measured, if there is a range where the melting peaks overlap within a range of ±2°C, it is determined that the synthetic fibers contained in each fiber layer contain the same polymer component.

The content of cellulose fibers in the second fiber layer 12 is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and preferably 100% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, based on the total mass of the second fiber layer 12. In other words, the second fiber layer 12 may be formed only from cellulose fibers. In addition, when the second fiber layer 12 contains synthetic fibers, the content of synthetic fibers in the second fiber layer 12 is preferably 0% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. The determination of whether the second fiber layer 12 contains cellulose fibers and the content thereof can be measured in the same manner as the measurement method for the first fiber layer 11 described above.

The thickness T1 (see FIG. 2) of the first fiber layer 11 is preferably 600 μm or less, more preferably 500 μm or less, even more preferably 450 μm or less, and preferably 100 μm or more, more preferably 200 μm or more. By reducing the thickness T1 within the above-mentioned range, the body fluid present on the wearer's skin can be quickly transferred to the second fiber layer, and the amount of fluid remaining on the skin can be further effectively reduced. In order to set the thickness T1 within the above-mentioned range, for example, it can be appropriately adjusted by using a latent crimping fiber such as a core-sheath type composite fiber as the constituent fiber of the first fiber layer 11, or by compressing the sheet in the thickness direction after production of the sheet.

The thickness T2 of the second fiber layer 12 (see FIG. 2) is preferably 250 μm or more, more preferably 300 μm or more, and is preferably 800 μm or less, more preferably 400 μm or less. This thickness ensures liquid retention on the second fiber layer 12 side while providing softness as a sheet.

The thickness T1 can be measured by the following method. First, the sheet 1 to be measured is immersed in liquid nitrogen under a load of 49 Pa to fix the sheet shape while maintaining the concave-convex structure. Next, the sheet 1 is cut in the thickness direction of the sheet 1 using a razor and a hammer so as to include the tops of the convex portions 18 of the sheet 1 and not to crush the cut surface, to obtain a cross section. Thereafter, the sheet cross section is observed with a microscope (manufactured by Keyence Corporation, digital microscope VHX-1000), and the length along the thickness direction from the boundary between the first fiber layer 11 and the second fiber layer 12 to the tops of the convex portions 18 is measured.
The boundary between the first fiber layer 11 and the second fiber layer 12 can be determined by determining the boundary between each region in which the constituent fibers of each fiber layer are mostly observed to be the same in thickness and type in an enlarged photograph of the sheet cross section obtained by microscope observation; alternatively, the sheet to be measured can be dyed by gently immersing it in ion-exchanged water containing 0.1% by mass of Blue No. 1, and then an enlarged photograph of the sheet cross section can be taken using a microscope, and the boundary between the layer with a relatively dark blue color and the layer with a relatively light blue color in the enlarged photograph can be determined to be the boundary between the first fiber layer 11 and the second fiber layer 12.
The above-mentioned length measurement is performed on an area including 100 different protrusions 18, and the arithmetic average of the thicknesses obtained at the 100 locations is defined as the thickness T1 of the first fiber layer 11. When the protrusions 18 are hollow, the length along the thickness direction from the first surface side of the second fiber layer 12 to the top of the protrusion 18 is measured and calculated by the above-mentioned method, and defined as thickness T1.
The thickness T2 of the second fiber layer 12 is determined by obtaining a cross section of the sheet using the same method as described above, measuring the length from the first surface side of the second fiber layer 12 to the second surface side at 100 different locations, and calculating the arithmetic average of the thicknesses obtained at the 100 locations.

As long as the effects of the present invention are achieved, there is no prohibition on disposing another fiber layer between the first fiber layer 11 and the second fiber layer 12.

It is preferable that the sheet for absorbent articles has a liquid remaining rate measured by the following measurement method that is equal to or less than a predetermined value. In detail, the liquid remaining rate of the sheet 1 is preferably equal to or less than 20%, more preferably equal to or less than 10%, and even more preferably equal to or less than 8%. By achieving such a value, when the sheet for absorbent articles is used as a component of an absorbent article, the sheet has a high ability to draw body fluids into the sheet side, and body fluids are less likely to remain on the wearer's skin, so that skin troubles caused by remaining body fluids on the skin can be effectively reduced.

The liquid remaining rate of the absorbent article sheet is measured by the following procedures (1) to (3).
<Method for measuring residual liquid rate>
(1) 49 drops of 1 mg each of ion-exchanged water are placed in a 5 cm square frame on a glass plate.
(2) The first surface of the absorbent article sheet cut into a 5 cm square is placed on a glass plate so that it comes into contact with each of the water droplets, and left to stand for 1 minute under a load of 0.8 kPa.
(3) The mass A (mg) of the water droplets remaining on the glass plate is measured, and the percentage of mass A to the total mass of the ion-exchanged water used is defined as the liquid remaining rate.

The method for measuring the liquid remaining rate described above will be explained in more detail. First, in an environment of 22±2°C temperature and 60±5% RH, a 2 mm thick, 10 cm square glass plate with a flat surface (hereinafter also referred to as the lower glass plate) is placed horizontally on a stand, and 49 drops of 1 mg x 49 drops of ion-exchanged water are placed in a 5 cm square frame in the center of the lower glass plate. Next, a sheet for absorbent articles cut into 5 cm squares is placed so that its first surface is in contact with each water drop on the lower glass plate, and in this state, a glass plate for loading having the same dimensions as the lower glass plate is further placed on the sheet and left to stand for 1 minute under a load of 0.8 kPa. Then, the glass plate for loading and the sheet for absorbent articles are removed, and the mass A (mg) of the water drops remaining on the lower glass plate is measured, and the percentage of the mass A relative to the total mass (49 mg) of the ion-exchanged water used is taken as the liquid remaining rate (%).
If the absorbent sheet to be measured cannot be cut into a square of 5 cm square, cut the sheet into the largest possible square, arrange 2 drops of 1 mg of ion-exchanged water ^per 1 cm2 of glass plate, and determine the liquid remaining rate using the method described above.

The sheet 1 having the above-mentioned configuration can be suitably manufactured, for example, by the following method. First, a fiber web or nonwoven fabric containing synthetic fibers that constitute the fiber aggregate of the first fiber layer 11, and a fiber web, nonwoven fabric, or paper containing cellulose fibers that constitute the fiber aggregate of the second fiber layer 12 are prepared by known web forming means or nonwoven fabric forming means. Then, the fiber aggregate of the first fiber layer 11 and the fiber aggregate of the second fiber layer 12 are stacked while being transported in the same direction to form a laminate.

In order to configure each fiber constituting the first fiber layer 11 and the second fiber layer 12 so as to satisfy the above-mentioned contact angle with water, for example, the surface of the synthetic fiber contained in the first fiber layer 11 may be hydrophilically treated in advance, or the fiber web or nonwoven fabric for constituting the first fiber layer 11 may be hydrophilically treated after its formation. In addition, as the constituent fibers of the second fiber layer 12, highly hydrophilic fibers such as pulp fibers may be used, or the surface of the constituent fibers of the second fiber layer 12 may be hydrophilically treated, or the fiber web or nonwoven fabric may be hydrophilically treated after its formation. In addition, the degree of hydrophilic treatment of the fiber web or nonwoven fabric constituting the first fiber layer 11 and the second fiber layer 12 may be appropriately adjusted to satisfy the desired contact angle.

Next, the laminate is introduced between the first roll and the second roll, and the embossed portion 15 is formed on the laminate, so that one side of the sheet is shaped into an uneven shape. The first roll has a plurality of convex portions on its peripheral surface, which are arranged in a scattered dot pattern or the like and have concave portions between the convex portions, in a pattern complementary to the desired uneven shape pattern. The second roll is an anvil roll with a smooth peripheral surface, which is arranged so that its axis and the axis of the first roll are parallel to each other and is arranged to abut against the peripheral surface of the first roll. The laminate is introduced between these rolls, and the laminate is clamped between the first roll and the anvil roll under non-heating or heating. From the viewpoint of easily forming unevenness on the first fiber layer side, it is preferable that the laminate is introduced so that the surface on the first fiber layer 11 side faces the peripheral surface of the first roll. In this case, the convex portions located on the peripheral surface of the first roll are intended to be the positions where the embossed portions 15 are to be formed, and the concave portions located on the peripheral surface of the first roll are intended to be the positions where the convex portions 18 are to be formed. This makes it possible to obtain the absorbent article sheet of the present invention in which the first surface F is shaped to have convex and concave portions.

In the above-mentioned process, for example, at least one of the convex portion of the first roll and the surface of the anvil roll is heated, and the laminate is pressed between the first roll and the anvil roll under heating to form the embossed portion 15. In this case, the fiber layers 11 and 12 are bonded by fusion at the position where the embossed portion 15 is formed. Such a method of forming the embossed portion 15 is known as a heat roll method.
The pressure application conditions and heating temperature in the first roll and the anvil roll when forming the embossed portion 15 on the laminate can be appropriately changed depending on the type of fiber constituting each fiber layer, but the pressure application conditions, expressed in terms of linear pressure, can be preferably 300 N/cm or more, more preferably 600 N/cm or more, and preferably 1500 N/cm or less, and more preferably 1200 N/cm or less. The heating conditions, under the above pressure application conditions, can be preferably 100°C or more, more preferably 110°C or more, and preferably 150°C or less, and more preferably 140°C or less.

As a method for forming the embossed portion 15 other than the heat roll, for example, an embossing method such as ultrasonic pressure or laser heating pressure can be used. In this case, the pressure condition is preferably 200 N/cm or more, more preferably 300 N/cm or more, and preferably 500 N/cm or less, more preferably 400 N/cm or less, expressed in terms of linear pressure. If heating is required, the heating temperature can be in the range described above.

In addition, when manufacturing a sheet 1 having an embossed portion 15 only in the first fiber layer 11 and no embossed portion in the second fiber layer 12, for example, a nonwoven fabric that has been embossed in advance, such as a spunbond nonwoven fabric, is used as the constituent material of the first fiber layer 11, and a fiber web or nonwoven fabric that has not been embossed is used as the constituent material of the second fiber layer 12, and these fiber layers are joined together using a joining means such as an adhesive.

The absorbent article sheet 1 described above can be preferably used as a component of an absorbent article. An absorbent article typically comprises a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retentive absorbent between these sheets. The absorbent article sheet can be used as a top sheet. In addition to or instead of this, the absorbent article sheet can be used as a component of an absorbent article other than the top sheet, back sheet, and absorbent. In either case, it is preferable that the absorbent article sheet 1 is arranged so that the first fiber layer 11 side, i.e., the first surface F, faces the body of the wearer of the absorbent article, forming the skin-contacting surface of the absorbent article. This configuration makes it easier to efficiently transfer body fluid that has migrated to the second fiber layer side through the first fiber layer to a member located on the non-skin-facing side of the second fiber layer, such as an absorbent.

The absorbent article comprising the absorbent article sheet 1 is mainly used to absorb and retain excreted body fluids such as urine, sweat, and menstrual blood. Such absorbent articles include, but are not limited to, pants-type or open-type disposable diapers, sanitary napkins, and incontinence pads, and broadly include articles used to absorb fluids discharged from the human body. As described above, the absorbent article sheet 1 has high sheet transferability of body fluids and is unlikely to remain on the wearer's skin, so it is preferable that the absorbent article sheet 1 is disposed at a site where the absorbent article and the wearer's skin come into direct contact. Examples of components disposed at such positions include, but are not limited to, one or more of the following: a top sheet, waist gathers and three-dimensional leak-proof gathers in a disposable diaper, a top sheet, and a sweat-absorbing sheet that constitutes the skin-facing surfaces of the ventral and dorsal waist flaps.

From the viewpoint of improving the feel on the first surface F of the sheet 1, the synthetic fibers constituting the first fiber layer 11 preferably have a fiber diameter of 10 μm or more, more preferably 15 μm or more, and preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of simultaneously increasing the capillary force of the first fiber layer 11 to facilitate liquid transfer to the second fiber layer 12 and not retaining water in the first fiber layer 11 that contacts the skin. In addition, from the viewpoint of ensuring the breathability of the second fiber layer 12, reducing the surface area of the fibers, and preventing absorbed body fluid from returning to the first fiber layer 11 side, the cellulose fibers constituting the second fiber layer 12 are preferably 10 μm or more, more preferably 15 μm or more, and preferably 45 μm or less, more preferably 40 μm or less. These fiber diameters can be determined, for example, by measuring the maximum cross-sectional length of the fiber perpendicular to the fiber length direction at one point per fiber using a scanning electron microscope or the like for 100 fibers as the measurement objects, and taking the arithmetic average value of the measured values.

The basis weight of the absorbent article sheet 1 is appropriately selected according to the specific use of the absorbent article, and is generally preferably 8 g/m ² or more, more preferably 15 g/m ² or more, and preferably 50 g/m ² or less, and more preferably 40 g/m ² or less. In addition, the basis weight of the first fiber layer 11 and the second fiber layer 12 constituting the absorbent article sheet 1 is preferably as high as possible from the viewpoint of ensuring a distance between the highly hydrophilic second fiber layer 12 and the wearer's skin in the first fiber layer 11 to enhance the dry feeling of the sheet 1 surface, and from the viewpoint of enhancing the liquid absorption and liquid retention in the second fiber layer 12. In detail, each of the fiber layers 11, 12 is independently preferably 4 g/m ² or more, more preferably 9 g/m ² or more, and realistically 30 g/m ² or less.

When continuous linear embossed lines 15A, 15B are formed as the embossed portion 15, the distance W1 (see FIG. 1(a)) between adjacent first embossed lines 15A formed on the sheet 1 is preferably 3 mm or more, more preferably 5 mm, and is preferably 15 mm or less, more preferably 12 mm or less. The distance W2 (see FIG. 1(a)) between adjacent second embossed lines 15B can be in the same range as the distance W1 described above.

When forming scattered embossed portions 15, the spacing W5 (see FIG. 1(b)) between the embossed portions 15 along the extension direction of the embossed portion row 15C composed of the embossed portions 15 formed on the sheet 1 is preferably 1 mm or more, and preferably 8 mm or less, and more preferably 5 mm or less. The spacing W6 (see FIG. 1(b)) between adjacent embossed portion rows 15C can be in the same range as the spacing W5 described above.

The present invention has been described above based on its preferred embodiments, but the present invention is not limited to the above embodiments.

The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples.

[Examples 1 and 2]
The constituent material of the first fiber layer 11 was an air-through nonwoven fabric (basis weight 15.2 g/m2 in Example 1, basis weight 14.6 g/m2 in Example 2) containing 90 mass% of synthetic fiber, i.e., a core-sheath type composite fiber (contact angle with water: 76.1°) that had been hydrophilically treated with a PET core and a PE sheath, and 10 mass% of ^Tencel (registered trademark, contact angle with water: 41.7° ⁾ as a cellulose fiber.
The second fiber layer 12 was made of wet-laid paper (basis weight 20 g/m2) containing 85% by mass of pulp fiber as cellulose fiber and 15% by mass of core-sheath composite fiber (contact angle with water: 97.7°) with a PET core and a PE sheath as synthetic fiber that had not been hydrophilized. These materials were laminated to form a laminate. The laminate was ultrasonically embossed from the first fiber layer ¹¹ side to produce absorbent article sheets (basis weight 35.2 g/ ^m2 in Example 1 and 34.6 g/ ^m2 in Example 2) with a concave-convex shape formed on the first surface F.
1(b) and 2(a), this sheet had scattered embossed portions 15 formed on the sheet plane, had solid protrusions 18, and the first fiber layer 11 and the second fiber layer 12 were joined by the embossed portions 15. The synthetic fibers in the first fiber layer 11 were made hydrophilic by a hydrophilization treatment in which a fiber oil was applied to the fiber surface during the production process of the synthetic fibers.
The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12 measured by the above-mentioned method are shown in the following Table 1. The synthetic fibers contained in the first fiber layer 11 and the second fiber layer 12 each contain the same polymer component. In this sheet, the embossed portion formed in the first fiber layer 11 was located on the second fiber layer 12 side.

Example 3
As in Example 1, an airlaid nonwoven fabric (basis weight 14.6 g/m2) was used as the constituent material of the first fiber layer 11, which contained 80 mass% of synthetic fiber (contact angle with water: 97.7°) that had not been hydrophilically treated with a core-sheath type composite fiber having a PET core and a PE sheath, and contained 20 mass% pulp fiber as a cellulose fiber. Except for this, an absorbent sheet (basis weight 34.6 g/ ^m2 ) was produced having the configuration shown in Figures 1(b) and 2(a), solid convex portions ¹⁸ , and an uneven shape formed on the first surface F.
The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12 measured by the above-mentioned method are shown in the following Table 1. The synthetic fibers contained in the first fiber layer 11 and the second fiber layer 12 each contain the same polymer component. In this sheet, the embossed portion formed in the first fiber layer 11 was located on the second fiber layer 12 side.

Example 4
The first fiber layer 11 was made of an air-through nonwoven fabric (basis weight 14.3 g/m2) containing 90% by mass of hydrophilically treated core-sheath composite fiber (contact angle with water: 76.1°) with a PET core and a PE sheath as synthetic fiber and 10% by mass of Tencel (registered trademark, contact angle with water: 42.5 ^° ) as cellulose fiber, and the first fiber layer 11 and the second fiber layer 12 were bonded together by forming an embossed portion 15 by ultrasonic embossing and bonding each fiber layer with a hot melt adhesive. Except for this, an absorbent article sheet (basis weight 34.3 g/m2) having the configuration shown in Figures 1(b) and ² (a), solid convex portions 18, and a concave-convex shape formed on the first surface F was produced in the same manner as in Example 1.
The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12 measured by the above-mentioned method are shown in the following Table 1. The synthetic fibers contained in the first fiber layer 11 and the second fiber layer 12 each contain the same polymer component. In this sheet, the embossed portion formed in the first fiber layer 11 was located on the second fiber layer 12 side.

Example 5
The first fiber layer 11 was made of an air-through nonwoven fabric (basis weight 14.5 g/m2) containing 90% by mass of synthetic fibers with a PET core and a PE sheath that had been hydrophilically treated (contact angle with water: 76.1°) and 10% by mass of Tencel (registered trademark, contact angle with water: 43.4°) as cellulose fibers. The second fiber layer 12 was made of an air-laid nonwoven fabric (basis weight 25 g/ ^m2 ) containing 80% by mass of pulp fibers as cellulose fibers and 15% by mass of synthetic fibers with a PET core and a PE sheath that had not been hydrophilically treated (contact angle with water: ^97.7 °). Other than that, similarly to Example 1, an absorbent sheet (basis weight 34.5 g/m2) having the configuration shown in Fig. 1(b) and Fig. ² (a), having solid convex portions 18, and having an uneven shape formed on the first surface F was produced.
The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12 measured by the above-mentioned method are shown in the following Table 1. The synthetic fibers contained in the first fiber layer 11 and the second fiber layer 12 each contain the same polymer component. In this sheet, the embossed portion formed in the first fiber layer 11 was located on the second fiber layer 12 side.

Example 6
The first fiber layer 11 was made of an air-through nonwoven fabric (basis weight 25 g/m2) containing 100% by mass of synthetic fibers with a PET core and a PE sheath that had been hydrophilically treated (contact angle with water: 76.1°). The second fiber layer 12 was made of wet-laid paper (basis weight 40 g/ ^m2 ) containing 90% by mass of pulp fiber as cellulose fiber and 10% by mass of synthetic fibers with a PET core and a PE sheath that had not been hydrophilically treated (contact angle with water: 97.7°). Except for this, an absorbent article sheet (basis weight 65 g/ ^m2 ) was produced in the same manner as in Example 1, having the configuration shown in Figures 1(b) and 2( ^a ), solid convex portions 18, and a concave-convex shape formed on the first surface F.
The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12 measured by the above-mentioned method are shown in the following Table 1. The synthetic fibers contained in the first fiber layer 11 and the second fiber layer 12 each contain the same polymer component. In this sheet, the embossed portion formed in the first fiber layer 11 was located on the second fiber layer 12 side.

Comparative Example 1
The constituent material of the first fiber layer 11 was an air-through nonwoven fabric (basis weight 15 g/ ^m2 ) containing 80 mass% synthetic fiber (contact angle with water: 97.7°) with a PET core and a PE sheath that had not been hydrophilically treated, and 20 mass% Tencel (registered trademark) as cellulose fiber. The constituent material of the second fiber layer 12 was a fiber web (basis weight 15 g/ ^m2 ) containing 100 mass% Tencel (registered trademark). These were hydroentangled and integrated to produce a sheet for absorbent articles (basis weight 30 g/ ^m2 ).
This sheet is a so-called spunlace nonwoven fabric, in which no embossed portion 15 is formed in each fiber layer, and no uneven structure is formed on the first surface F. The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12, measured by the above-mentioned method, are shown in Table 1 below.

Comparative Example 2
The first fiber layer 11 was made of a spunbond nonwoven fabric (basis weight 10 g/ ^m2 ) containing 100% by mass of non-hydrophilized polypropylene fiber (contact angle with water: 108.2°), and the second fiber layer 12 was made of a spunbond nonwoven fabric containing 100% by mass of hydrophilized polypropylene fiber (contact angle with water: 74.8°). A hot melt adhesive was applied between the first fiber layer 11 and the second fiber layer 12 were bonded together to produce a sheet for absorbent articles (basis weight 30 g/ ^m2 ). In this sheet, the embossed portion 15 was formed only in the first fiber layer 11, and the uneven structure was formed on the first surface F. In this sheet, the embossed portion formed in the first fiber layer 11 was located on the second fiber layer 12 side. The thickness T1 of the first fiber layer 11, the Klemm water absorption height C1 of the first fiber layer 11, and the Klemm water absorption height C2 of the second fiber layer 12, measured by the above-mentioned method, are shown in Table 1 below.

[Evaluation of remaining amount of liquid and remaining rate of liquid]
The sheets of the examples and comparative examples were evaluated for the amount of remaining liquid and the liquid remaining rate under conditions of a temperature of 22±2° C. and a humidity of 60±5% RH. In detail, the above-mentioned method for measuring the liquid remaining rate of a sheet for absorbent articles was followed, and the mass A (mg) of the water droplets remaining on the lower glass plate was taken as the amount of remaining liquid in this evaluation, and the percentage of mass A to the total mass (49 mg) of the ion-exchanged water used was taken as the liquid remaining rate (%). The results are shown in Table 1. The smaller the mass (mg) of the ion-exchanged water remaining on the lower glass plate and the smaller the liquid remaining rate, the better the liquid transferability to the sheet, i.e., the less likely body fluids such as sweat to remain on the wearer's skin.

As shown in Table 1, the absorbent article sheet of the embodiment has a lower amount and percentage of residual liquid compared to the comparative example sheet. In particular, by controlling the thickness of the first fiber layer 11 to a predetermined range, the amount and percentage of residual liquid can be further reduced. Therefore, an absorbent article having the absorbent article sheet of the present invention arranged on the skin contact surface is less likely to retain body fluids such as sweat on the wearer's skin, and skin troubles caused by body fluids remaining on the skin can be reduced.

Reference Signs List 1: Sheet for absorbent articles 2: Synthetic fibers 3: Cellulosic fibers 11: First fiber layer 12: Second fiber layer 15: Embossed portion 17: Concave portion 18: Convex portion

Claims (10)

a first fibrous layer including a first surface and including synthetic fibers;
a second fiber layer including a second surface that is a surface opposite to the first surface and including 75% by mass or more of cellulose fibers;
the first fibrous layer comprises fibers having a contact angle with water of less than 90°;
An embossed portion is formed in the first fiber layer,
a concave-convex shape having a plurality of concave portions formed by the embossed portion and convex portions formed between the concave portions is formed on the first surface,
the Klemm water absorption height of the second fiber layer measured in accordance with JIS P8141 is 4 cm or more;
the Klemm water absorption height of the first fiber layer measured in accordance with JIS P8141 is 3 cm or more lower than the Klemm water absorption height of the second fiber layer measured in accordance with JIS P8141;
A sheet for absorbent articles , wherein when the first fiber layer contains cellulose fibers, the proportion of the cellulose fibers contained in the first fiber layer is lower than the proportion of the cellulose fibers contained in the second fiber layer . The absorbent article sheet according to claim 1, wherein the first fiber layer and the second fiber layer are joined by the embossed portion. The absorbent article sheet according to claim 1 or 2, wherein the first fiber layer further contains cellulose fibers. the cellulose fibers constituting the second fibrous layer are pulp fibers,
The sheet for absorbent articles according to any one of claims 1 to 3, wherein the second fibrous layer is paper. The absorbent article sheet according to any one of claims 1 to 4, wherein the first fiber layer further comprises either regenerated cellulose fibers or semi-synthetic cellulose fibers. the second fibrous layer further comprises synthetic fibers;
The absorbent sheet according to any one of claims 1 to 5, wherein the synthetic fibers contained in the first fiber layer and the synthetic fibers contained in the second fiber layer each contain the same polymer component. The absorbent article sheet according to any one of claims 1 to 6, wherein the thickness of the first fiber layer under a load of 49 Pa is 600 μm or less. The sheet for absorbent articles according to any one of claims 1 to 7, in which the liquid remaining rate is 20% or less. The sheet for absorbent articles according to any one of claims 1 to 8, wherein the first fiber layer has a Klemm water absorption height of 1 cm or less, as measured in accordance with JIS P8141. The absorbent article sheet according to any one of claims 1 to 9 is provided.
The sheet is used as a top sheet or a sweat-absorbing sheet in an absorbent article.

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