WO2023153402A1 - Absorbent sheet and absorbent sheet production method - Google Patents

Abstract

An absorbent sheet (1) has an absorbent core (10), a liquid-permeable front surface sheet (11), and a rear surface sheet (12). If a region spanning from the side edge in the vertical direction or horizontal direction of the absorbent sheet (1) to a position inside the absorbent sheet (1) by the length of the average thickness of the absorbent sheet (1) is defined as a side edge section, the absorbent core (10) extends to the side edge section of the absorbent sheet (1) in the vertical direction and extends to the side edge section of the absorbent sheet (1) in the horizontal direction.

Description

ABSORBENT SHEET AND METHOD FOR MANUFACTURING ABSORBENT SHEET

The present invention relates to an absorbent sheet and a method for manufacturing an absorbent sheet.

As an absorbent sheet, an absorbent sheet for pets used for processing pet excrement is known. Patent Document 1 discloses an absorbent sheet for pets comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and a rectangular absorbent body interposed between the two sheets.

JP 2018-153144 A

However, in the pet absorbent sheet disclosed in Patent Document 1, the top sheet and the back sheet extend in all directions from the periphery of the absorbent body, and are joined together at the extending portions. Therefore, there is no absorber over the entire periphery of the absorbent sheet. Therefore, when excreted on the peripheral portion of the absorbent sheet, the excreted liquid is received by the portion where the absorbent body does not exist, and the excreted liquid leaks out of the absorbent sheet. In addition, a portion of the sheet where the absorber does not exist, such as the peripheral portion of the absorbent sheet, has low rigidity and tends to be turned over. When the peripheral edge of the absorbent sheet is turned up, the absorbent surface is likely to be covered with the turned up sheet, and when excreted on the part where the absorbent surface is covered with the sheet, the excreted liquid leaks out of the absorbent sheet without being absorbed. end up

The present invention has been made in view of the conventional problems as described above, and an object thereof is to provide an absorbent sheet in which excretory fluid is less likely to leak to the outside.

The main invention for achieving the above object has a vertical direction, a horizontal direction and a thickness direction,
An absorbent core comprising liquid-absorbent fibers and a superabsorbent polymer, a liquid-permeable surface sheet disposed on the front side in the thickness direction of the absorbent core, and the absorbent core in the thickness direction. and a back sheet arranged on the back side of the absorbent sheet, and from the longitudinal or transverse side edge of the absorbent sheet, the length of the average thickness of the absorbent sheet inward When the region up to the entering position is defined as a side edge portion, the absorbent core exists up to the side edge portion of the absorbent sheet in the longitudinal direction, and the absorbent core extends to the side edge portion of the absorbent sheet in the lateral direction. The absorbent sheet is characterized in that it exists up to the side edges.
Other features of the present invention will become apparent from the description of the specification and accompanying drawings.

According to the present invention, it is possible to provide an absorbent sheet that makes it difficult for excretions to leak outside.

Fig. 2 is a plan view of the absorbent sheet 1 viewed in the thickness direction; 2A and 2B are side views along the thickness direction of the absorbent sheet 1. FIG. It is a cross-sectional schematic diagram explaining the modification of the absorbent sheet 1 of 1st Embodiment. 4A and 4B are diagrams showing modifications of the compressing portion 20. FIG. It is explanatory drawing of the manufacturing method of the continuous body 2 of an absorber. FIG. 4 is an explanatory diagram of a method for manufacturing the absorbent sheet 1; 7A is an explanatory diagram of a method for measuring the weight variation of the absorbent sheet 1, and FIG. 7B is a diagram illustrating the measurement result of the weight variation of the absorbent sheet 1. FIG. 8A and 8B are explanatory diagrams of the hitting test. It is a figure which shows the result of a hitting test. 10A and 10B are explanatory diagrams of the absorbent sheet 1 of the second embodiment.

At least the following matters will become apparent from the descriptions of this specification and the accompanying drawings.
An absorbent core having a longitudinal direction, a transverse direction, and a thickness direction, and comprising liquid-absorbent fibers and a superabsorbent polymer, and a liquid-permeable surface disposed on the front side in the thickness direction of the absorbent core. and a back sheet disposed on the back side of the absorbent core in the thickness direction, wherein from the side edge of the absorbent sheet in the longitudinal direction or the lateral direction, the The absorbent core extends up to the side edges of the absorbent sheet in the longitudinal direction, when the side edges are defined as the area extending inward by the length of the average thickness of the absorbent sheet. and the absorbent sheet extending to the side edges of the absorbent sheet in the lateral direction.

According to such an absorbent sheet, the absorbent core can receive the excreted liquid even when excreted on the peripheral edge of the absorbent sheet. Moreover, it is possible to prevent the absorbent surface of the absorbent sheet from being covered with the sheet extending from the absorbent core. Therefore, leakage of excrement to the outside of the absorbent sheet can be suppressed.

Also, an absorbent core having a longitudinal direction, a transverse direction and a thickness direction and comprising liquid-absorbent fibers and a superabsorbent polymer, and a liquid-permeable absorbent core disposed on the front side in the thickness direction of the absorbent core and a back sheet disposed on the back side of the absorbent core in the thickness direction, the absorbent sheet in at least one of the longitudinal direction and the transverse direction An absorbent sheet, wherein the absorbent core is exposed on each side along the thickness direction of a pair of side edges of the absorbent sheet.

According to such an absorbent sheet, the excrement can be absorbed even from the sides of the absorbent sheet where the absorbent core is exposed, and leakage of the excrement to the outside of the absorbent sheet can be suppressed. In addition, the fact that the absorbent core is exposed on the side surface of the absorbent sheet means that the absorbent core exists up to the side edge of the absorbent sheet or a position close thereto. Therefore, even when excreted on the periphery of the absorbent sheet, the absorbent core can receive the excreted liquid, and the absorbent surface of the absorbent sheet is not covered with the sheet extending from the absorbent core. can be suppressed.

In such an absorbent sheet, the absorbent core is exposed on each side along the thickness direction of a pair of side edges of the absorbent sheet in both the longitudinal direction and the lateral direction. An absorbent sheet characterized by:

According to such an absorbent sheet, excreted liquid can be absorbed from all sides in four directions of the absorbent sheet. In addition, the absorbent core is present up to all of the side edges in four directions or a position close thereto. Therefore, leakage of excrement to the outside of the absorbent sheet can be further suppressed.

An absorbent sheet as described above, wherein the absorbent sheet has a uniform thickness in a non-compressed portion where the absorbent sheet is not compressed in the thickness direction.

According to such an absorbent sheet, it is possible to prevent only a part of the surface of the absorbent sheet from protruding in the thickness direction. It is possible to prevent tripping over parts.

In this absorbent sheet, the absorbent core is a pair of side edges in at least one of the longitudinal direction and the lateral direction, and is attached to each side along the thickness direction of the sheet from the outside. An absorbent sheet having a pair of covered sides.

According to such an absorbent sheet, since the side surface of the absorbent core is covered with the sheet, the absorbent core (especially the superabsorbent polymer) can be prevented from falling off from the absorbent sheet. Absorption performance is ensured.

In this absorbent sheet, at least the absorbent core has the thickness along a pair of side edges of the absorbent sheet in at least one of the longitudinal direction and the lateral direction. It has a pair of pressing parts that are pressed in the width direction, and when the maximum length of the absorbent sheet in the one direction is X mm, the pressing part is 1/4 of X mm from the side edge. An absorbent sheet, characterized in that it is provided within a region up to a position that extends inward in the one direction by the length thereof.

According to such an absorbent sheet, excreted fluid can be diffused while being dammed by the compressed portion, so that leakage of excreted fluid to the outside of the absorbent sheet can be suppressed. In addition, the absorbent sheet can be effectively utilized over a wide range in the planar direction.

This absorbent sheet is characterized in that the compressed portion is provided in a region inside the side edge in the one direction.

According to such an absorbent sheet, the excreted liquid can be diffused while being dammed by the inner compressed portion, so that the excreted liquid becomes difficult to reach the side edges of the absorbent sheet. Therefore, it is possible to prevent the absorbent core (particularly the superabsorbent polymer) positioned at the side edge of the absorbent sheet from absorbing the excreted fluid, swelling, and falling off easily.

In such an absorbent sheet, the absorbent sheet has at least one other compressed portion along the side edge, which is spaced inside the compressed portion in the one direction. An absorbent sheet characterized by:

According to such an absorbent sheet, the excreted liquid can be diffused while being dammed up by the compressed portion on the inner side, so that the excreted liquid becomes difficult to reach the side edges of the absorbent sheet, and the absorbent core swollen with the excreted liquid falls off. It can be suppressed that it becomes easy to do. In addition, since the absorbent core near the side edge of the absorbent sheet is strongly joined in the thickness direction by the compressed portion on the outside, the absorbent core can be prevented from coming off.

In such an absorbent sheet, the absorbent sheet has a core wrap sheet covering the front side surface of the absorbent core in the thickness direction, and is bonded between the absorbent core and the core wrap sheet. An absorbent sheet characterized in that no agent is provided.

According to such an absorbent sheet, it is possible to prevent the adhesive from inhibiting the absorption of excrement into the absorbent core. Therefore, the absorption performance of the absorbent sheet can be ensured.

In such an absorbent sheet, the absorbent sheet has a core wrap sheet covering at least one surface of the absorbent core in the thickness direction, the liquid absorbent fibers include pulp fibers, The absorbent sheet, wherein the core wrap sheet contains cellulosic fibers, and the pulp fibers are hydrogen-bonded to the cellulosic fibers.

According to such an absorbent sheet, the absorbent core (pulp fiber) and the core wrap sheet (cellulose fiber) are strongly bonded by hydrogen bonding, and the absorbent core can be prevented from falling off from the absorbent sheet.

In such an absorbent sheet, the absorbent sheet before absorption is relatively reciprocated between a pair of striking plates in a direction intersecting the plane of the absorbent sheet, and a predetermined portion on the plane of the absorbent sheet is moved. When a pounding test is conducted in which the pair of pounding plates are brought into contact with each other in a reciprocating motion for 1 minute at a rate of 1000 times per minute, the weight of the absorbent sheet before the pounding test is calculated from the weight of the absorbent sheet before the pounding test. When the value obtained by subtracting the weight of the absorbent sheet after performing the above is taken as the amount of falling off, the value obtained by dividing the amount of falling off by the weight of the absorbent sheet before performing the hitting test is 0.5 % or less.

According to such an absorbent sheet, the absorption performance of the absorbent sheet is maintained as compared with the case where the value obtained by dividing the amount of falling off by the weight of the absorbent sheet before the beating test is greater than 0.5%. can.

In such an absorbent sheet, the absorbent sheet before absorption is relatively reciprocated between a pair of striking plates in a direction intersecting the plane of the absorbent sheet, and a predetermined portion on the plane of the absorbent sheet is moved. The superabsorbent polymer does not fall off from the absorbent sheet in a pounding test in which the pair of pounding plates are brought into contact with each other in a reciprocating motion at a speed of 1000 times per minute for 1 minute. absorbent sheet.

According to such an absorbent sheet, the absorption performance of the absorbent sheet can be maintained.

In such an absorbent sheet, the absorbent sheet is divided into regions each having a length of 40 mm in the vertical direction and a length of 40 mm in the horizontal direction, and the absorbent core is present in the entire region. The absorbent sheet is characterized in that, when the weight of each of the divided regions is measured, the CV value of the weight variation of the divided regions is 10% or less.

According to such an absorbent sheet, the absorbent core (especially the superabsorbent polymer) is distributed evenly in the planar direction of the absorbent sheet compared to the case where the CV value of the weight variation of the divided regions is greater than 10%. distributed. Therefore, when the absorbent sheet is manufactured, force can be uniformly applied to the absorbent sheet in the thickness direction, and the bonding strength in the thickness direction of the absorbent sheet increases. Therefore, falling off of the absorbent core from the absorbent sheet can be suppressed.

Also, an absorbent core having a longitudinal direction, a transverse direction and a thickness direction and comprising liquid-absorbent fibers and a superabsorbent polymer, and a liquid-permeable absorbent core disposed on the front side in the thickness direction of the absorbent core and a back sheet disposed on the back side of the absorbent core in the thickness direction, wherein the continuous body of the top sheet continues in the conveying direction; a step of forming a laminate continuum in which a continuum of absorbent cores continuous in the conveying direction and a continuum of the backsheet continuing in the conveying direction are laminated while being conveyed in the conveying direction; A step of cutting the continuum of the laminate while conveying the continuum of the laminate so that the length of the continuum of the laminate in the conveying direction corresponds to the length of the absorbent sheet in the longitudinal direction or the lateral direction. And, a manufacturing method of an absorbent sheet characterized by having.

According to such an absorbent sheet manufacturing method, an absorbent sheet in which an absorbent core exists up to a side edge portion in a direction corresponding to the conveying direction, or an absorbent sheet having an absorbent core on a side surface of a side edge portion in a direction corresponding to the conveying direction. An absorbent sheet with an exposed core can be produced.

===Embodiment===
Hereinafter, embodiments of the absorbent sheet according to the present invention will be described. INDUSTRIAL APPLICABILITY The absorbent sheet according to the present invention can be used, for example, as an absorbent sheet for animals that treat excrement of animals such as pets. In this case, the absorbent sheet can be used alone, or the absorbent sheet can be installed in an animal litter box for use. In addition, the absorbent sheet according to the present invention can be used for various purposes such as a childcare sheet, a nursing care sheet, a medical sheet, etc. used for changing diapers, preventing bedding from becoming dirty, and the like.

===First embodiment===
<<Basic Configuration of Absorbent Sheet 1>>
FIG. 1 is a plan view of the absorbent sheet 1 viewed in the thickness direction. 2A and 2B are side views along the thickness direction of the absorbent sheet 1. FIG. 2A is a side view of lateral side edges 1c and 1d of absorbent sheet 1, and FIG. 2B is a side view of longitudinal side edges 1a and 1b of absorbent sheet 1. FIG. Note that FIG. 2A is a common view showing a side surface at the side edge 1c on one side in the horizontal direction and a side surface at the side edge 1d on the other side in the horizontal direction. FIG. 2B is a common view showing the side surface of the side edge 1a on one side in the vertical direction and the side surface of the side edge 1b on the other side in the vertical direction.

The absorbent sheet 1 is a sheet having a vertical direction, a horizontal direction, and a thickness direction that are orthogonal to each other, and has a rectangular planar shape when viewed in the thickness direction. The planar shape of the absorbent sheet 1 is not limited to a rectangle. It may be in shape. When the absorbent sheet 1 of this embodiment has different lengths in the vertical direction and the horizontal direction, the longitudinal direction of the absorbent sheet 1 is defined as the vertical direction, and the lateral direction of the absorbent sheet 1 is defined as the horizontal direction. Further, when the absorbent sheet 1 has a shape other than a square, the linear direction along the longest portion of the absorbent sheet 1 is defined as the vertical direction (longitudinal direction), and the direction perpendicular to that direction is defined as the horizontal direction.

The absorbent sheet 1 comprises an absorbent core 10, a liquid-permeable surface sheet 11 arranged on the front side of the absorbent core 10 in the thickness direction, and a back side of the absorbent core 10 in the thickness direction. It has a back sheet 12 . The absorbent core 10 is obtained by mixing an aggregate of liquid absorbent fibers 101 with a super absorbent polymer 102 (SAP: Super Absorbent Polymer). As the liquid absorbent fiber 101, cellulosic fiber (for example, pulp fiber, non-wood fiber such as cotton and hemp, regenerated fiber such as rayon, etc.), hydrophilically treated thermoplastic synthetic fiber (for example, polyethylene, polypropylene, etc.) can be exemplified. Examples of the liquid-permeable surface sheet 11 include a nonwoven fabric and a perforated film. Examples of the backsheet 12 include a liquid-impermeable sheet (eg, resin film) and a liquid-impermeable sheet (eg, SMS nonwoven fabric, water-repellent nonwoven fabric, etc.).

Also, the absorbent sheet 1 may be a double-sided absorbent sheet, and the back sheet 12 may be a liquid-permeable sheet like the top sheet 11 . Such an absorbent sheet 1 may be used in combination with other absorbent articles and absorbent sheets as an article that supplementarily absorbs excrement.

The absorbent sheet 1 includes a core wrap sheet 13 (also referred to as a first core wrap sheet 13) that covers the front surface of the absorbent core 10 in the thickness direction, and a core wrap sheet that covers the back surface of the absorbent core 10. It has a sheet 14 (also referred to as a second core wrap sheet 14). The core wrap sheets 13 and 14 are liquid-permeable sheets. Examples of the core wrap sheets 13 and 14 include tissues, nonwoven fabrics, perforated films, and the like.

In addition, the absorbent sheet 1 has a pressed portion 20 in which at least the absorbent core 10 is pressed in the thickness direction on a part of its plane. The compressed portion 20 is a portion where the absorbent core 10 is recessed in the thickness direction compared to the surrounding area, is thin, and has a higher density of the absorbent core 10 (liquid absorbent fibers 11) than the surrounding area.

In the compressed part 20 illustrated in FIG. 2A and the like, the entire absorbent sheet 1 is compressed from the top sheet 11 side. However, without being limited to this, the pressing part 20 is, for example, only the absorbent core 10 is pressed, only the absorbent core 10 and the core wrap sheets 13 and 14 are pressed, or the absorbent sheet 1 may be squeezed from the back sheet 12 side.

In addition, in the pressing portion 20, the inside of the pressing portion 20 may be uniformly pressed (grooved) or may be pressed in a predetermined pattern. Examples of the region of the pressing portion 20 that is pressed in a predetermined pattern include, for example, a plurality of small pressing portions arranged discretely and a plurality of small pressing portions arranged linearly. . In addition, a plurality of types of pressing portions having different pressing strengths (depths of dents) may be provided in the region within the pressing portion 20 .

<<About the absorbent core 10>>
In the absorbent sheet 1 of the first embodiment, the absorbent sheet 1 and the absorbent core 10 have the same planar shape and planar area, and the absorbent sheet 1 and the absorbent core 10 are stacked so that their outer peripheral edges are aligned. It is Therefore, as shown in FIG. 1, the side edges 1a and 1b of the absorbent sheet 1 in the longitudinal direction and the side edges 10a and 10b of the absorbent core 10 in the longitudinal direction are aligned, and the absorbent sheet 1 in the lateral direction The lateral edges 1c, 1d of the absorbent core 10 coincide with the lateral edges 10c, 10d of the absorbent core 10 .

In this way, the absorbent core 10 preferably extends to the side edges 1ab of the absorbent sheet 1 in the longitudinal direction and to the side edges 1cd of the absorbent sheet 1 in the lateral direction. By doing so, even when excreted on the outer peripheral edge of the absorbent sheet 1, the excreted liquid can be received by the absorbent core 10 and is absorbed and held by the absorbent core 10. - 特許庁Therefore, it is possible to suppress leakage of the excreted liquid to the outside of the absorbent sheet 1 .

In addition, if the top sheet 11, the back sheet 12, etc., extend farther than the absorbent core 10, the sheet only has low rigidity and is likely to be turned over. For example, the animal may turn over the sheet only portion when playing, or the sheet portion may be easily turned over when the absorbent sheet 1 is larger than the tray of the animal litter box. Therefore, since the absorbent core 10 exists up to the side edges 1ab and 1cd like the absorbent sheet 1 of the first embodiment, the portion of the sheet extending beyond the absorbent core 10 is eliminated or shortened. You can As a result, the sheet can be prevented from being turned over and covering the absorbent surface of the absorbent sheet 1, and the excreted liquid can be drawn into the absorbent sheet 1 and leaked to the outside of the absorbent sheet 1. You can prevent it from happening.

The areas from the longitudinal or lateral side edges 1a to 1d of the absorbent sheet 1 to the position inside the absorbent sheet 1 by the length of the average thickness of the absorbent sheet 1 are defined as "side edge portions 1ab, 1cd". . By doing so, the length of the backsheet 12 extending beyond the absorbent core 10 is shorter than the average thickness of the absorbent sheet 1, so that the backsheet 12 can be turned over and folded back onto the topsheet 11. Therefore, it is possible to prevent the absorbent surface from being covered with the backsheet 12.例文帳に追加

The average thickness of the absorbent sheet 1 is measured using an Ozaki Seisakusho dial thickness gauge large type JB or equivalent. In setting the measurement points, first, the central portion when the absorbent sheet 1 is divided into three parts by the maximum width in the lateral direction is defined. Next, the central portion is divided into three by the maximum length in the vertical direction to define three regions (both ends and the central portion in the vertical direction). One, preferably a plurality of measurement points are set for each of the three regions. The measurement point is the non-squeezed part and is a part away from the folding part for packaging. Then, a pressure of 3.0 gf/cm ² is applied to the set measurement points, and the thickness of the absorbent sheet 1 at each point is measured. The average value of the thickness of the absorbent sheet 1 obtained at all measurement points is calculated, and the average value is defined as the average thickness of the absorbent sheet.

In addition, as shown in FIG. 2A, the absorbent core 10 may be exposed on each side along the thickness direction at the positions of the pair of side edges 1c and 1d of the absorbent sheet 1 in the lateral direction. Similarly, as shown in FIG. 2B, the absorbent core 10 may be exposed on each side along the thickness direction at the positions of the pair of side edges 1a and 1b of the absorbent sheet 1 in the longitudinal direction.

The expression that the absorbent core 10 is exposed on the side surface of the absorbent sheet 1 means that the absorbent core 10 is visible when the side surface of the absorbent sheet 1 is viewed. Specifically, the absorbent core 10 can be visually recognized by visually observing the side surface of the absorbent sheet 1, or the absorbent core 10 can be visually confirmed in an image obtained by enlarging the side surface of the absorbent sheet 1 with an electron microscope or the like. It would be nice if there was.

In this case, the excreted liquid is easily absorbed from the sides of the absorbent sheet 1 as well. Therefore, even when the excreted liquid flows out from the surface of the absorbent sheet 1, the excreted liquid is absorbed from the side surface of the absorbent sheet 1, and the amount of the excreted liquid leaking to the outside of the absorbent sheet 1 can be reduced. For example, when the absorbent sheet 1 is installed in the tray of an animal litter box, the excreted liquid that flows into the tray is easily absorbed from the sides of the absorbent sheet 1 .

In addition, when manufacturing the absorbent sheet 1, the process of folding back the sheet covering the absorbent core 10, etc. is not required, which facilitates manufacturing. In addition, since the area of the sheet covering the side surface of the absorbent core 10 is not required, the amount of consumption of the sheet can be reduced and the cost can be reduced.

In addition, the fact that the absorbent core 10 is visible from the side surface of the absorbent sheet 1 means that the absorbent core 10 exists up to the side edges 1a to 1d of the absorbent sheet 1 or a position close thereto. Therefore, the effects described above can be obtained. That is, the excreted liquid can be absorbed by the outer peripheral edge of the absorbent sheet 1, and the absorbent surface can be prevented from being covered with the turned-up sheet.

In particular, in the absorbent sheet 1 illustrated in FIG. 1, the absorbent core 10 is exposed on each side along the thickness direction of the pair of side edges 1a to 1d of the absorbent sheet 1 in both the longitudinal direction and the lateral direction. are doing. Therefore, the excreted liquid is easily absorbed from all four sides of the absorbent sheet 1 , and the excreted liquid is less likely to leak out of the absorbent sheet 1 .

FIG. 3 is a cross-sectional schematic diagram illustrating a modification of the absorbent sheet 1 of the first embodiment. Not limited to the above, the absorbent core 10 may be exposed only on the side surface of the absorbent sheet 1 in one of the longitudinal direction and the horizontal direction, or the absorbent core 10 may be exposed on the side surface of the absorbent sheet 1. It doesn't have to be exposed at all.

That is, as shown in FIG. 3, the absorbent core 10 has a pair of side edges in at least one of the vertical direction and the horizontal direction, and each side surface 10S along the thickness direction is a sheet from the outside. It may have a pair of covered sides 10S. In FIG. 3 , the backsheet 12 extending beyond the absorbent core 10 is folded back while covering the side surface 10S of the absorbent core 10 and positioned on the topsheet 11 . However, it is not limited to this, and the sheet covering the side surface 10S of the absorbent core 10 may be the surface sheet 11 or the core wrap sheets 13 and 14 .

In this case, since the side surface 10S of the absorbent core 10 is covered with the sheet, the absorbent core 10 can be prevented from falling off from the side surface of the absorbent sheet 1. Therefore, the absorption performance of the absorbent sheet 1 (especially the side edge portions 1ab and 1cd) is ensured, and leakage of the excreted liquid to the outside of the absorbent sheet 1 can be suppressed. In addition, it is possible to suppress exudation of the excreted liquid absorbed by the absorbent core 10 from the side surface of the absorbent sheet 1 .

Moreover, as shown in FIGS. 2A and 2B, in the non-compressed portion of the absorbent sheet 1 where the absorbent sheet 1 is not compressed in the thickness direction, the thickness T of the absorbent sheet 1 is uniform. good. The non-compressed portion is a portion other than the compressed portion 20 where the plane of the absorbent sheet 1 is partially compressed. Suppose it is included. Further, the fact that the thickness T of the absorbent sheet 1 is uniform means that it is substantially uniform, excluding errors that occur in the manufacturing process.

Since the thickness T of the absorbent sheet 1 is uniform, only a part of the surface of the absorbent sheet 1 protrudes in the thickness direction when the absorbent sheet 1 is installed on an installation surface such as a floor surface. can be prevented. If only a portion of the surface of the absorbent sheet 1 protrudes upward, there is a risk that the protruded portion may be bitten by an animal and the absorbent sheet 1 may be damaged. Moreover, if the surface of the side edges of the absorbent sheet 1 protrudes in the thickness direction compared to the surface of the central portion, there is a possibility that the animal may trip over it. Therefore, as shown in FIGS. 2A and 2B, when the absorbent sheet 1 is installed on the installation surface, the height (position in the thickness direction) of the surface of the absorbent sheet 1 (non-squeezed portion) is the same. is preferred.

In addition, by making the thickness T of the absorbent sheet 1 (uncompressed portion) uniform, it is possible to make the same material structure laminated in the thickness direction over the entire planar surface of the absorbent sheet 1 . Therefore, as shown in FIGS. 2A and 2B, the absorbent core 10 can be present up to the side edges 1a to 1d of the absorbent sheet 1, and the absorbent core 10 can be exposed on the side surfaces of the absorbent sheet 1 (FIG. 2B). Do not fold back sheet 12 as shown in 3). Further, by making the thickness T of the absorbent sheet 1 uniform, the basis weight of the absorbent core 10 can be made constant over the entire planar surface of the absorbent sheet 1 . Therefore, the absorbent performance is ensured over the entire plane of the absorbent sheet 1 . Moreover, since the process of folding back the sheet is not necessary, the manufacturing of the absorbent sheet 1 is facilitated.

In addition, as shown in FIG. 1, the absorbent sheet 1 has a pair of lateral compressed parts 21 along a pair of side edges 1a and 1b of the absorbent sheet 1 in the longitudinal direction (one direction). Assuming that the maximum length of the absorbent sheet 1 in the longitudinal direction (one direction) is Xl (X mm), the horizontal pressing part 21 extends from the laterally extending side edges 1a and 1b to 1/ of the maximum length Xl. It is preferable that it is provided within a region up to a position that is vertically inward by a length of 4.

Similarly, the absorbent sheet 1 has a pair of longitudinal compressed portions 22 along a pair of side edges 1c and 1d of the absorbent sheet 1 in the lateral direction (one direction). Assuming that the maximum length of the absorbent sheet 1 in the horizontal direction (one direction) is Xw (X mm), the vertical compression part 22 extends from the side edges 1c and 1d extending in the vertical direction to 1/ of the maximum length Xw. It may be provided within a region up to a position that is laterally inward by a length of 4.

By doing so, the excreted fluid can be diffused in the horizontal direction and the vertical direction in the horizontal compression part 21 and the vertical compression part 22, and leakage of the excreted fluid from the absorbent sheet 1 can be suppressed. In addition, the absorbent sheet 1 can be effectively utilized over a wide area in the plane direction by diffusing the excrement.

In addition, in the pressing portion 20, the absorbent cores 10 are strongly entangled with each other, and the absorbent cores 10 and the sheet laminated in the thickness direction are strongly joined and integrated. Therefore, even if the absorbent core 10 exists up to the side edges 1ab and 1cd like the absorbent sheet 1 of the first embodiment, the laterally compressed portion 21 and the vertical compressed portion near the side edges 1ab and 1cd The portion 22 can prevent the absorbent core 10 from falling off from the absorbent sheet 1 . Therefore, the absorption performance of the absorbent sheet 1 (especially the side edge portions 1ab and 1cd) can be ensured, and leakage of excrement from the absorbent sheet 1 can be suppressed.

Preferably, the horizontal pressing portion 21 is provided in a region vertically inward of the side edges 1a and 1b extending in the horizontal direction, that is, at a position spaced apart from the side edges 1a and 1b. Similarly, the vertical pressing portion 22 is preferably provided in a region laterally inward of the longitudinally extending side edges 1c, 1d, that is, provided at a position spaced from the side edges 1c, 1d.

By doing so, the excreted liquid can be diffused while being dammed by the horizontal compressing portion 21 and the vertical compressing portion 22, so that the amount of the excreted liquid reaching the side edges 1a to 1d beyond the horizontal compressing portion 21 and the vertical compressing portion 22 can be reduced. can be reduced. Therefore, leakage of excrement from the absorbent sheet 1 can be suppressed. In addition, the absorbent core 10 present at the side edges 1ab and 1cd of the absorbent sheet 1 absorbs excrement and swells, and the absorbent core 10 (particularly the superabsorbent polymer 102) tends to fall off. can be suppressed.

The compressed portions 20 along the side edges 1a to 1d of the absorbent sheet 1 are the compressed portions 20 elongated in the direction in which the side edges 1a to 1d extend. Therefore, the compressed portion 20 is not limited to linearly extending parallel to the vertical direction or the horizontal direction, and may be, for example, a compressed portion extending in a meandering manner. Further, the length of the compressed portion 20 may be shorter than the side edges 1a to 1d of the absorbent sheet 1.

Further, the compressed portions 20 are not limited to being provided along the four side edges 1a to 1d. For example, the absorbent sheet 1 may be provided with only the compressed portions 20 extending in one of the vertical and horizontal directions. For example, the pressing portion 20 may be provided only on the side of the absorbent sheet 1 where the absorbent core 10 is exposed. By doing so, even if the absorbent core 10 is exposed, the compression part 20 can prevent the absorbent core 10 from coming off and prevent the excreted liquid from seeping out from the absorbent core 10 .

FIGS. 4A and 4B are diagrams showing modifications of the compressing portion 20. FIG. As shown in FIG. 4A, the absorbent sheet 1 may have at least one other laterally compressed portion 211 along the same side edges 1a and 1b inside the laterally compressed portion 21 in the longitudinal direction. Similarly, the absorbent sheet 1 may have at least one other vertically compressed portion 221 along the same side edges 1c and 1d inside the vertically compressed portion 22 in the horizontal direction. Although FIG. 4A illustrates a case where the pressing portions 20 are arranged in a double row, three or more horizontal pressing portions 21 or vertical pressing portions 22 may be arranged at intervals.

In this case, since the excreted liquid can be diffused while being dammed by the inner laterally compressed portion 211 and the vertically compressed portion 221, leakage of the excreted liquid from the absorbent sheet 1 can be suppressed. In addition, the absorbent core 10 present at the side edges 1ab and 1cd of the absorbent sheet 1 absorbs excrement and swells, and the absorbent core 10 (particularly the superabsorbent polymer 102) tends to fall off. can be suppressed. Moreover, even if the excreted liquid flows over the inner horizontal compression part 211 and the vertical compression part 221, the external horizontal compression part 21 and the vertical compression part 22 can dam up the excreted liquid and diffuse it. Further, even when the absorbent core 10 exists up to the side edge portions 1ab and 1cd like the absorbent sheet 1 of the first embodiment, the absorbent sheet is 1 can be suppressed.

Alternatively, as shown in FIG. 4B, only a plurality of compressed portions 20 along a pair of side edges of the absorbent sheet 1 in one of the vertical direction and the horizontal direction may be arranged at intervals. For example, by providing a plurality of compressed portions 20 on the side of the absorbent sheet 1 where the absorbent core 10 is exposed, it is possible to prevent the absorbent core 10 from coming off and the exudate from the absorbent core 10 to seep out. .

Although the pressing unit 20 has been described above, it is not limited to the above. For example, the absorbent sheet 1 may not have the pressed portions 21 and 22 along the side edges 1a to 1d, and dot-like pressed portions may be dispersedly arranged. Also, the absorbent sheet 1 may not have the pressing portion 20 .

Also, it is preferable that no adhesive is provided between the absorbent core 10 and the first core wrap sheet 13 located on the front side of the absorbent core 10 . By doing so, it is possible to prevent absorption inhibition by the adhesive on the surface of the absorbent core 10 and to draw excrement into the absorbent core 10 . Therefore, the absorption performance of the absorbent core 10 is ensured, and leakage of excrement from the absorbent sheet 1 can be suppressed.

In addition, when the absorbent sheet 1 is a double-sided absorbent sheet and the back sheet 12 is a liquid-permeable sheet, the absorbent core 10 and the second core wrap sheet 14 positioned on the back side are also bonded. Preferably no agent is provided. However, it is not limited to the above, and the absorbent core 10 may be joined to the core wrap sheets 13 and 14 with an adhesive.

The liquid absorbent fibers 101 constituting the absorbent core 10 contain pulp fibers, and the core wrap sheets 13 and 14 contain cellulosic fibers (for example, pulp fibers, non-wood fibers such as cotton and hemp, recycled fibers such as rayon). fiber, etc.). The pulp fibers of the liquid absorbent fibers 101 are preferably hydrogen-bonded with the cellulose fibers of the core wrap sheets 13 and 14 .

By doing so, the liquid absorbent fiber 101 and the core wrap sheets 13, 14 are firmly joined. Therefore, even if an adhesive cannot be provided between the absorbent core 10 and the core wrap sheets 13 and 14 as described above, the peeling of the core wrap sheets 13 and 14 and the adhesion between the core wrap sheets 13 and 14 It is possible to suppress the falling off of the absorbent core 10 from.

In particular, when the absorbent sheet 1 is formed with the compressed portions 20, the liquid absorbent fibers 101 and the core wrap sheets 13 and 14 are more firmly hydrogen-bonded in the compressed portions 20, and this state is maintained. Further, the liquid absorbent fibers 101 are also hydrogen-bonded to each other, and the entangled state is easily maintained. Therefore, like the absorbent sheet 1 of the first embodiment, the absorbent core 10 may extend to the side edges 1ab and 1cd of the absorbent sheet 1, or the absorbent core 10 may be exposed from the side surfaces of the absorbent sheet 1. Even if the absorbent core 10 does not fall off from the absorbent sheet 1, the absorption performance of the absorbent sheet 1 can be maintained.

It should be noted that confirmation of whether the liquid absorbent fibers 101 (absorbent core 10) include pulp fibers and whether the core wrap sheets 13 and 14 include cellulose fibers can be confirmed by a well-known method. For example, it can be confirmed by using an identification dye that colors the fiber or by observing the fiber with an optical microscope or the like. However, the present invention is not limited to the above, and the liquid absorbent fibers 101 may not contain pulp fibers, and the core wrap sheets 13 and 14 may not contain cellulose fibers.

<<Manufacturing method of absorbent sheet 1>>
FIG. 5 is an explanatory diagram of a method for manufacturing the continuous body 2 of absorbent bodies. FIG. 6 is an explanatory diagram of the manufacturing method of the absorbent sheet 1. FIG. Next, an example of a method for manufacturing the absorbent sheet 1 will be described. 5 and 6, the vertical direction (longitudinal direction) of the absorbent sheet 1 (absorbent core 10) corresponds to the transport direction (MD direction) of the manufacturing apparatuses 40 and 50, and the absorbent The lateral direction of the sheet 1 corresponds to the CD direction that intersects the conveying direction of the manufacturing apparatuses 40 and 50 . However, it is not limited to this, and the opposite direction may correspond.

FIG. 5 shows an apparatus 40 for manufacturing the continuous body 2 of absorbent bodies. A laminate of the first core wrap sheet continuum 13 ′, the absorbent core continuum 10 ′, and the second core wrap sheet continuum 14 ′ is referred to as an absorbent continuum 2 . The manufacturing apparatus 40 has supply rollers 41 and 43 for supplying materials, an air laying machine 42 , a water spray 44 , a press roller 45 and a take-up roller 46 .

In the method for manufacturing the continuous body 2 of absorbent bodies, the supply roller 41 supplies the continuous body 14' of the second core wrap sheet to the production line. The absorbent core 10 (liquid absorbent fibers 101 and A superabsorbent polymer 102) is deposited. The absorbent core 10 is continuously supplied from the airlaid machine 42 . In FIG. 5, the second core wrap sheet continuum 14' is conveyed horizontally, but the present invention is not limited to this, and the second core wrap sheet continuum 14' may be wound around a rotating drum and conveyed. good.

Next, the supply roller 43 supplies the continuous body 13' of the first core wrap sheet onto the continuous body 10' of the absorbent core. Next, a water spray 44 sprays water onto the laminate of the first core wrap sheet continuum 13′, the absorbent core continuum 10′, and the second core wrap sheet continuum 14′. be done. After that, the entire surface of the laminate is evenly pressed in the thickness direction by the press rollers 45 . The press rollers 45 are composed of a pair of rollers and may be heated or unheated, but the heated rollers can strongly press the laminate.

Thereby, the absorbent sheet 1 can be manufactured in which the absorbent core 10 and the core wrap sheets 13 and 14 are hydrogen-bonded and the hydrogen-bonded state is easily maintained. The position of the water spray 44 is not limited to the position shown in FIG. Water may be jetted from the top or bottom.

Thus, the continuous body 2 of absorbent bodies is manufactured, and the continuous body 2 of absorbent bodies is wound up by the winding roller 46 . The roll body of the absorbent continuous body 2 is set in a manufacturing apparatus 50 for the absorbent sheet 1 shown in FIG.

The manufacturing apparatus 50 for the absorbent sheet 1 includes supply rollers 51 , 53 , 55 , adhesive discharge units 52 , 54 for discharging hot melt adhesive, water spray 56 , squeeze rollers 57 , 58 , and cutting roller 59 . have

The manufacturing method of the absorbent sheet 1 is as follows. First, an adhesive is applied to the upper surface of the back sheet continuous body 12 ′ supplied from the supply roller 51 by the adhesive discharge section 52 , and the absorbent body continuous body 2 supplied from the supply roller 53 is applied thereon. Laminated. Further, the adhesive is applied to the upper surface of the continuous body 2 of absorbent bodies by the adhesive discharge section 54, and the continuous body 11' of the topsheet supplied from the supply roller 55 is laminated thereon. In this way, a continuum of laminates in which a continuum 11' of the top sheet continuing in the conveying direction, a continuum 2 of the absorbent cores continuing in the conveying direction, and a continuum 12' of the back sheet continuing in the conveying direction are laminated. 1' is formed.

Next, a water spray 56 sprays water onto the laminate continuum 1'. This causes hydrogen bonding between cellulosic materials. Therefore, it is possible to manufacture the absorbent sheet 1 in which the constituent materials are firmly bonded. The positions and number of water sprays 56 are not limited to those shown in FIG.

Next, the compression rollers 57 form the vertical compression part 22 , and the compression rollers 58 form the horizontal compression part 22 . Each of the pressing rollers 57 and 58 is composed of a pair of rollers, and convex portions corresponding to the shape of the pressing portion 20 are formed on the outer peripheral surface of one or both of the pair of rollers. The squeezing rollers 57 and 58 may be heated or unheated, but the heated rollers 57 and 58 can strongly squeeze the laminate.

Finally, the cutting roller 59 cuts the laminate continuum 1'. The cutting roller 59 is composed of a pair of rollers, one roller is provided with a cutter blade corresponding to the cutting position on the outer peripheral surface thereof, and the other roller is configured to receive the cutter blade of the one roller.

At this time, while transporting the continuous body 1' of the laminate in the transport direction, the continuous body 1' of the laminate is cut so that the length of the continuous body 1' of the laminate in the transport direction becomes the length of the absorbent sheet 1 in the vertical direction or the horizontal direction. do. In the present embodiment, the laminate continuum 1 ′ is intermittently cut in the conveying direction every length Xl of the absorbent sheet 1 in the vertical direction. When the conveying direction corresponds to the lateral direction of the absorbent sheet 1, the laminate continuum 1' is intermittently cut in the conveying direction every length Xw of the absorbent sheet 1 in the lateral direction.

Thereby, it is possible to manufacture the absorbent sheet 1 in which the absorbent core 10 exists up to the pair of side edges 1a and 1b of the absorbent sheet 1 in the direction corresponding to the conveying direction (vertical direction here). Moreover, the absorbent sheet 1 in which the absorbent core 10 is exposed on the side surface of the absorbent sheet 1 in the direction corresponding to the conveying direction can be manufactured.

Furthermore, in the above-described manufacturing method, the length of the CD direction (horizontal direction) of each sheet continuum 11′ to 14′ is the same, and the absorbent core 10 extends over the entire width of the sheet continuum 11′ to 14′. should be deposited. By doing so, the absorbent core 10 exists up to the pair of side edges 1c and 1d of the absorbent sheet 1 in the direction corresponding to the CD direction (here, the lateral direction), and the absorbent sheet 1 in the direction corresponding to the CD direction , the absorbent sheet 1 in which the absorbent core 10 is exposed can be produced.

When manufacturing a rectangular absorbent sheet 1 as shown in FIG. 1, it is preferable to cut the laminate continuum 1' along a straight cutting line along the CD direction. When the absorbent sheet 1 has a shape other than a quadrilateral shape, for example, a mold having the same shape as that of the absorbent sheet 1 may be used to cut the continuous body 1' of the laminate. Also in this case, the absorbent core 10 is exposed on the side surface of the absorbent sheet 1 in the direction corresponding to the conveying direction.

Here, as a general absorbent core manufacturing apparatus (not shown), one using a pattern drum is known. The pattern drum is a rotary drum having a plurality of molding dies (concave portions) corresponding to the shape of the absorbent core provided at predetermined intervals on the outer peripheral surface of the rotating drum. A suction hole is provided in the bottom surface of the mold, and the liquid-absorbing fibers and superabsorbent polymer scattered from the duct facing the pattern drum are deposited on the mold. The absorbent cores deposited in the mold are sequentially released from the pattern drum and transferred to a core wrap sheet or the like.

However, in the case of the manufacturing method of the absorbent core using the pattern drum, the absorbent core cannot be released cleanly from the molding die, or the liquid absorbent fibers may fly when the absorbent core is transferred to the core wrap sheet. It may get stuck and the super absorbent polymer may roll. Therefore, it is difficult to distribute the materials evenly in the planar direction of the absorbent core, and the variation in the materials tends to increase particularly in the outer peripheral edge of the absorbent core. In such a case, the absorbent core will have insufficient absorption performance at the outer peripheral edge, and it will be necessary to deposit materials more than necessary to make up for the deficiency.

On the other hand, according to the manufacturing method of the absorbent core 10 illustrated in FIG. Problems in the case of using a pattern drum (problems such as the inability to cleanly cut out the absorbent core and the occurrence of variations in materials when transferring the absorbent core) are less likely to occur. Therefore, the absorbent cores 10 can be evenly distributed over the entire planar surface of the absorbent sheet 1 as compared with the case of using a pattern drum.

Therefore, when pressure is applied to the absorbent core 10 in the thickness direction by the press roller 45 shown in FIG. 5 and the compression rollers 57 and 58 shown in FIG. As a result, the absorbent core 10 and the sheet member can be firmly joined together in the thickness direction. Therefore, like the absorbent sheet 1 of the first embodiment, the absorbent core 10 is present up to the side edges 1ab and 1cd of the absorbent sheet 1, or the absorbent core 10 is exposed on the side surfaces of the absorbent sheet 1. Even if the absorbent core 10 is attached to the absorbent sheet 1, it is possible to prevent the absorbent core 10 from falling off. However, the manufacturing method described above is merely an example, and the method is not limited to this. For example, the absorbent core 10 may be manufactured using a pattern drum.

<<Example of Absorbent Sheet 1: Measurement of Weight Variation>>
7A is an explanatory diagram of a method for measuring the weight variation of the absorbent sheet 1, and FIG. 7B is a diagram illustrating the measurement result of the weight variation of the absorbent sheet 1. FIG. Samples (Examples and Comparative Examples) of the absorbent sheet 1 were actually prepared, and the weight variation of the absorbent sheet 1 was measured.

The samples of the example were manufactured by the manufacturing method shown in FIGS. 5 and 6. FIG. The planar shape of the sample of the example is a square (rectangle), and the vertical length Xl (440 mm) is the horizontal length Xw (320 mm). The absorbent core 10 was manufactured using an airlaid machine, and the basis weight of the liquid absorbent fibers (pulp fibers) was 75 g/m ² and the basis weight of the superabsorbent polymer was 63 g/m ² . As shown in FIGS. 2A and 2B, the absorbent core 10 extends to four side edges 1a to 1d of the absorbent sheet 1 and is exposed on four side surfaces of the absorbent sheet 1. As shown in FIGS. In addition, the core wrap sheets 13 and 14 are tissue (basis weight 13 g/m ² ), the top sheet 11 is an air-through nonwoven fabric (basis weight 22 g/m ² ), and the back sheet 12 is a resin film (basis weight 18 g/m ^{2 )} . ).

In addition, as shown in FIG. 5, the sample of the example was obtained by flat-pressing the absorbent core 10 and the core wrap sheets 13 and 14 with press rollers heated to 180°C. After that, as shown in FIG. 6 , after all the materials were laminated, water was sprayed on the materials, and a pressing roller heated to 65° C. formed a pressing portion 20 . As in FIG. 1, a horizontal compressed portion 21 and a vertical compressed portion 22 having a width of 5 mm were formed at positions 7 mm inward from the side edges 1a to 1d of the absorbent sheet 1. As shown in FIG. Although no adhesive is provided between the absorbent core 10 and the core wrap sheets 13 and 14, adhesives are not provided between the top sheet 11 and the core wrap sheet 13, and between the back sheet 13 and the core wrap sheet 14. is provided with adhesive.

The sample of the comparative example has the same shape and the same size (440 mm×320 mm) as the sample of the example, but unlike the sample of the example (FIG. 1), the horizontally compressed portion 21 and the vertically compressed portion 22 are formed. do not have. Further, the basis weight (75 g/m ² ) of the liquid absorbent fibers (pulp fibers) constituting the absorbent core 10 and the basis weight (63 g/m ² ) of the superabsorbent polymer 102 are the same as those in the example. However, in the comparative examples, a pattern drum was used to produce the absorbent cores. Specifically ^, a super absorbent polymer (45 ^g /m ² ) was dispersed to form a layer of superabsorbent polymer to form an absorbent core 10 . In addition, in the sample of the comparative example, the absorbent core 10 was smaller than the absorbent sheet 1, and a region where the absorbent core 10 did not exist was provided at the outer peripheral edge of the absorbent sheet 1 (width 25 to 30 mm). In addition, the core wrap sheets 13 and 14 are tissues (13.5 g/m ² basis weight on the front side, 13 g/m ² basis weight on the back side), and the top sheet 11 is an air-through nonwoven fabric (22 g/m ² basis weight). A resin film (basis weight: 18 g/m ² ) was used as the back sheet 12 .

In addition, in the sample of the comparative example, the core wrap sheets 13, 14 and the absorbent core 10 were also joined with an adhesive, and flat pressing was not performed. The top sheet 11 and the core wrap sheet 13, and the core wrap sheet 14 and the back sheet 12 were also joined with an adhesive. Further, in the comparative example, no water injection was performed before the flat pressing and the forming of the pressing portions 21 and 22 were performed.

Next, the weight variation was measured for the absorbent sheet of the example and the absorbent sheet of the comparative example. The measuring method is as follows. First, as shown in FIG. 7A, the plane of a rectangular absorbent sheet is divided into square regions each having a vertical length of 40 mm and a horizontal length of 40 mm. Let the area|region where the absorptive core 10 exists in the whole square area|region be a "divided area." The absorbent sheets of Examples and Comparative Examples have a longitudinal length of 440 mm and a lateral length of 320 mm. Therefore, the absorbent sheet was divided into 11 sections in the longitudinal direction and 8 sections in the transverse direction, and partitioned into 88 regions (A1 to A11, B1 to B11 . . . H1 to H11).

In the sample of the example, since the absorbent core 10 exists up to the side edges 1a to 1d of the absorbent sheet 1, all 88 regions are divided regions. In the sample of the comparative example, since the absorbent core 10 is one size smaller than the absorbent sheet 1, there are 54 regions (B2 to B10, C2 to C10 . . . G2 to G10) excluding the outer peripheral region of the absorbent sheet 1. is the divided area.

In addition, a vertex of the absorbent sheet (rectangle) is taken as the origin, and it is divided into sections with a length of 40 mm on one side in the vertical direction from the origin, and sections with a length of 40 mm on one side in the horizontal direction from the origin. Go ahead. If the side length of the absorbent sheet is not a multiple of 40, areas smaller than 40 mm x 40 mm are excluded from the measurement. In addition, when the absorbent sheet is not rectangular, a virtual quadrangle is formed with one side having the maximum length in the vertical direction of the absorbent sheet and one side having the maximum length in the horizontal direction of the absorbent sheet. It is good to divide into the area|region of 40 mm x 40 mm.

After cutting out the divided regions from the absorbent sheet 1, the weight (g) of each divided region is measured. Then, the average value (g) and the standard deviation of the weight of the divided regions are calculated for each sample, and the CV value is calculated by dividing the standard deviation by the average value (standard deviation/average value). The results are shown in FIG. 7B.

As shown in FIG. 7B, in the sample of the comparative example, the average value of each weight of 54 divided regions was 0.33283 (g) and the standard deviation was 0.03615, so the CV value was 10.86. %Met. On the other hand, in the sample of Example, the average value of each weight of the 88 divided regions was 0.34942 (g) and the standard deviation was 0.02846, so the CV value was 8.15%. there were.

From the above results, compared to the absorbent sheet of the comparative example in which the absorbent core 10 was manufactured using a pattern drum, the absorbent sheet 1 of the example in which the absorbent core 10 was manufactured using an airlaid machine, It was found that the CV value, which indicates variation, is small, and the variation in weight is small. It can be said that the fact that the weight variation of the absorbent sheet 1 is small means that the variation of the absorbent core 10 is also small. Therefore, in the absorbent sheet 1 of the embodiment, force is likely to be evenly applied to the material in the thickness direction during flat pressing or formation of the compressed portion 20, and the material is more firmly joined in the thickness direction.

Therefore, in the absorbent sheet 1, it is preferable to set the CV value indicating the weight variation of the divided regions to 10% or less (that is, smaller than the CV value when the absorbent core 10 is manufactured using a pattern drum). By doing so, the materials constituting the absorbent sheet 1 are joined more firmly in the thickness direction than when the CV value, which indicates the weight variation of the divided regions, is greater than 10%. Therefore, like the absorbent sheet 1 of the first embodiment, the absorbent core 10 exists up to the side edges 1ab and 1cd of the absorbent sheet 1, and the absorbent core 10 is exposed on the side surface of the absorbent sheet 1. Even when the absorbent core 10 is attached to the absorbent sheet 1, it is possible to prevent the absorbent core 10 from falling off.

<<Example of Absorbent Sheet 1: Beating Test>>
8A and 8B are explanatory diagrams of the hitting test of the absorbent sheet 1. FIG. FIG. 9 is a diagram showing the results of the hitting test. Samples of the absorbent sheet 1 (Examples 1 to 4, Comparative Example) were actually prepared, and a tapping test was performed on the samples.

The composition and manufacturing method of the sample are roughly the same as the sample created when measuring the weight variation. However, the size of the sample was 100 mm in the vertical direction and 60 mm in the horizontal direction. Also in the samples of the comparative examples, the absorbent core 10 was present up to the four side edges 1a to 1d of the absorbent sheet 1, and the absorbent core 10 was exposed on the four side surfaces of the absorbent sheet 1. 1, all the samples were provided with laterally compressed portions 21 and vertically compressed portions 22 having a width of 5 mm at positions 7 mm inward from the side edges 1a to 1d of the absorbent sheet 1. Further, in the samples of Examples 1 to 4, as shown in FIG. 9, the basis weight of the superabsorbent polymer (SAP) was varied.

The hitting test is performed by the following method.
(1) First, the absorbent sheet 1 (sample) before absorption (dry state) is set on the vibrator 60 that reciprocates in the direction (thickness direction) intersecting the plane of the absorbent sheet 1 . As shown in FIG. 8A, the absorbent sheet 1 is set so that the horizontal direction is aligned with the vertical direction, and the absorbent sheet 1 is gripped from below by the chuck portion 601 of the vibrator 60 . At this time, in order to prevent the absorbent sheet 1 from sagging, the area gripped by the chuck part 601 has a length of about 30 to 50% of the length Xw of the lateral edge of the absorbent sheet 1 along the lateral direction. , the length of which is about 10 to 30% of the length Xl of the side edge of the absorbent sheet 1 along the longitudinal direction.

(2) Next, a pair of striking plates 61 and 62 (for example, an acrylic plate) are fixed and installed at positions contacting part of the flat surface of the absorbent sheet 1 . A pair of striking plates 61 and 62 are positioned in a direction of motion intersecting the plane of the absorbent sheet 1 with a space therebetween. Also, as shown in FIG. 8B, the absorbent sheet 1 is arranged between a pair of striking plates 61 and 62 . The distance between the pair of striking plates 61 and 62 should be about the maximum thickness of the absorbent sheet 1 (for example, 5 mm). In order to prevent the absorbent core 10 (particularly the superabsorbent polymer 102) from falling off from the absorbent sheet 1, the areas hit by the hitting plates 61 and 62 are the side edges along the lateral direction of the absorbent sheet 1. The length of the region is about 30 to 50% of the length Xw, and the length of the region is about 10 to 30% of the length Xl of the side edge along the longitudinal direction of the absorbent sheet 1 . In addition, the striking plates 61 and 62 are adapted to strike the ends of the absorbent sheet 1 in the longitudinal direction opposite to the side where the chuck portion 601 is located.

(3) Next, vibrate the vibration shaft portion 602 extending downward in the vertical direction from the chuck portion 601 of the vibrator 60 to move the absorbent sheet 1 between the pair of striking plates 61 and 62. It is reciprocated in the motion direction (thickness direction) intersecting the plane. Specifically, the reciprocating motion of the absorbent sheet 1 (movement of the absorbent sheet 1 to one side in the movement direction and movement of the absorbent sheet 1 to the other side in the movement direction) is performed 1000 times per minute, The absorbent sheet 1 is reciprocated for 1 minute. At this time, part of the flat surface of the absorbent sheet 1 abuts against the pair of striking plates 61 and 62, and the absorbent sheet 1 vibrates. Note that the striking plates 61 and 62 may be reciprocated with respect to the absorbent sheet 1 .

After the pounding test, the sample was visually observed to see if the superabsorbent polymer (SAP) had fallen off, and the results are shown in FIG. Also, FIG. 9 shows the results of measuring the weight (g) of the samples before the hitting test. The weight of the sample after the beating test was also measured, and the value obtained by subtracting the weight of the sample after the test from the weight of the sample before the test was calculated as the "shedding amount (g)". Further, the dropout amount (g) was divided by the weight of the sample before the beating test, and the value was calculated as the "dropout rate (%)". Those results are also shown in FIG. In addition, in this example, three samples were prepared for each sample, and the average values of the results of the hitting test on the three samples are shown in FIG.

As shown in FIG. 9, the shedding rate (1.33%) of the sample of the comparative example was larger than the shedding rate (0.13-0.45%) of the samples of Examples 1-4. . In addition, in the sample of the comparative example, detachment of the superabsorbent polymer was confirmed, but in the samples of Examples 1 to 4, detachment of the superabsorbent polymer was not confirmed.

This is because the samples of Examples 1 to 4, in which the absorbent core 10 was manufactured using the airlaid machine, showed greater variation in weight than the comparative sample, in which the absorbent core 10 was manufactured using the pattern drum. It is thought that this is because when the pressed portions 21 and 22 are formed, a uniform force is easily applied to the material in the thickness direction, and the material is joined more firmly in the thickness direction.

Therefore, when the tapping test is performed on the absorbent sheet 1, the dropout rate is 0.5% or less (similar to the dropout rates of Examples 1 to 4 in which the SAP did not come off). preferable. By doing so, falling off of the absorbent core 10 from the absorbent sheet 1 can be suppressed as compared with the case where the falling off rate in the beating test is higher than 0.5%.
Moreover, it is preferable that the superabsorbent polymer does not come off when the absorbent sheet 1 is subjected to a tapping test.

By doing so, like the absorbent sheet 1 of the first embodiment, the absorbent core 10 exists up to the side edges 1ab and 1cd of the absorbent sheet 1, and the absorbent core Even when the absorbent core 10 is exposed, it is possible to prevent the absorbent core 10 from falling off from the absorbent sheet 1 . Absorption performance of the absorbent sheet 1 (especially the side edge portions 1ab and 1cd) is ensured.

=== Second Embodiment ===
10A and 10B are explanatory diagrams of the absorbent sheet 1 of the second embodiment. In the absorbent sheet 1 of the first embodiment, the absorbent core 10 exists up to four side edges 1ab and 1cd of the absorbent sheet 1 in the longitudinal direction and the lateral direction. On the other hand, in the absorbent sheet 1 of the second embodiment, each side surface along the thickness direction of the pair of side edges of the absorbent sheet 1 in at least one of the longitudinal direction and the lateral direction is As shown in 10B, the absorbent core 10 only needs to be exposed.

Therefore, as long as the absorbent core 10 is visible from the side surface of the absorbent sheet 1, the absorbent core 10 may be located inside the side edges 1ab and 1cd of the absorbent sheet 1. Moreover, as shown in FIG. 10A, the absorbent core 10 may not be exposed on each side surface of the pair of side edges 1a and 1b in one of the vertical and horizontal directions (vertical direction here). . For example, a pair of side surfaces of the absorbent core 10 in the longitudinal direction may be covered with a sheet as shown in FIG. 3 described above. Alternatively, as shown in FIG. 10A, the absorbent core 10 is located relatively large inside from the side edges 1a and 1b of the absorbent sheet 1, and the top sheet 11 and the back sheet extending from the absorbent core 10 are separated. 12 may be joined.

In the above case as well, excreted liquid is more likely to be absorbed from the sides of the absorbent sheet 1 where the absorbent core 10 is exposed. In addition, the fact that the absorbent core 10 is visible from the side of the absorbent sheet 1 means that the absorbent core 10 exists up to the side edges 1a to 1d of the absorbent sheet 1 or a position close thereto. Therefore, the excreted liquid can be absorbed by the outer peripheral edge of the absorbent sheet 1, and the absorbent surface can be prevented from being covered with the turned-up sheet. Therefore, the amount of excrement leaking out of the absorbent sheet 1 can be reduced. In addition, since the process of folding back the sheet covering the absorbent core 10 is unnecessary or reduced, the production is facilitated. In addition, since the area of the sheet for covering the side surface of the absorbent core 10 is small or not required, the consumption of the sheet can be reduced and the cost can be reduced.

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

1 absorbent sheet,
10 absorbent core,
101 liquid-absorbent fiber, 102 super-absorbent polymer,
11 front sheet, 12 back sheet,
13, 14 core wrap sheet,
20 compression unit, 21 horizontal compression unit, 22 vertical compression unit,
40 manufacturing device, 41, 43 supply roller, 42 airlaid machine,
44 water spray, 45 press roller, 46 winding roller 50 manufacturing device, 51, 53, 55 supply roller,
52, 54 adhesive discharge part, 56 water spray,
57, 58 squeezing rollers, 59 cutting rollers,
60 vibrator, 61, 62 tapping plate,

Claims (14)

1. having a longitudinal direction, a transverse direction and a thickness direction,
   an absorbent core comprising liquid-absorbent fibers and superabsorbent polymers;
   a liquid-permeable surface sheet arranged on the front side in the thickness direction relative to the absorbent core;
   a back sheet disposed on the back side in the thickness direction of the absorbent core;
   An absorbent sheet having
   When the area from the longitudinal or lateral side edge of the absorbent sheet to the position inside the absorbent sheet by the length of the average thickness of the absorbent sheet is defined as the side edge,
   The absorbent core is present up to the side edge of the absorbent sheet in the longitudinal direction and is present up to the side edge of the absorbent sheet in the lateral direction. sheet.
2. having a longitudinal direction, a transverse direction and a thickness direction,
   an absorbent core comprising liquid-absorbent fibers and superabsorbent polymers;
   a liquid-permeable surface sheet arranged on the front side in the thickness direction relative to the absorbent core;
   a back sheet disposed on the back side in the thickness direction of the absorbent core;
   An absorbent sheet having
   The absorbent core is exposed on each side along the thickness direction of a pair of side edges of the absorbent sheet in at least one of the longitudinal direction and the lateral direction. absorbent sheet.
3. The absorbent sheet according to claim 2,
   An absorbent sheet, wherein the absorbent core is exposed on each side surface along the thickness direction of a pair of side edges of the absorbent sheet in both the longitudinal direction and the lateral direction.
4. The absorbent sheet according to any one of claims 1 to 3,
   An absorbent sheet, wherein the absorbent sheet has a uniform thickness in a non-compressed portion where the absorbent sheet is not compressed in the thickness direction.
5. The absorbent sheet according to claim 1 or 2,
   The absorbent core has a pair of side edges in at least one of the longitudinal direction and the lateral direction, each side along the thickness direction, the pair of side faces being covered with a sheet from the outside. An absorbent sheet characterized by comprising:
6. The absorbent sheet according to any one of claims 1 to 5,
   The absorbent sheet includes a pair of absorbent cores compressed in the thickness direction along a pair of side edges of the absorbent sheet in at least one of the longitudinal direction and the lateral direction. having a pressing section,
   When the maximum length of the absorbent sheet in one direction is X mm,
   The absorbent sheet, wherein the compressed portion is provided within a region from the side edge to a position inside the one direction by a length of 1/4 of X mm.
7. The absorbent sheet according to claim 6,
   The absorbent sheet, wherein the compressed portion is provided in a region inside the side edge in the one direction.
8. The absorbent sheet according to claim 6 or 7,
   The absorbent sheet has at least one other compressed portion along the side edge, the absorbent sheet being spaced inside the compressed portion in the one direction.
9. The absorbent sheet according to any one of claims 1 to 8,
   The absorbent sheet has a core wrap sheet covering the front surface of the absorbent core in the thickness direction,
   An absorbent sheet, wherein no adhesive is provided between the absorbent core and the core wrap sheet.
10. The absorbent sheet according to any one of claims 1 to 9,
    The absorbent sheet has a core wrap sheet that covers at least one surface of the absorbent core in the thickness direction,
    The liquid-absorbing fibers comprise pulp fibers,
    The core wrap sheet contains cellulosic fibers,
    The absorbent sheet, wherein the pulp fibers are hydrogen-bonded with the cellulosic fibers.
11. The absorbent sheet according to any one of claims 1 to 10,
    The absorbent sheet before absorption is relatively reciprocated between a pair of striking plates in a direction intersecting the plane of the absorbent sheet, and a predetermined portion of the absorbent sheet on the plane is brought into contact with the pair of striking plates. When a hitting test was conducted in which the reciprocating motion was performed for 1 minute at a speed of 1000 times per minute,
    When the value obtained by subtracting the weight of the absorbent sheet after the beating test from the weight of the absorbent sheet before the beating test is taken as the dropout amount,
    The absorbent sheet, wherein a value obtained by dividing the amount of falling off by the weight of the absorbent sheet before the hitting test is 0.5% or less.
12. The absorbent sheet according to any one of claims 1 to 11,
    The absorbent sheet before absorption is relatively reciprocated between a pair of striking plates in a direction intersecting the plane of the absorbent sheet, and a predetermined portion of the absorbent sheet on the plane is brought into contact with the pair of striking plates. When a hitting test was conducted in which the reciprocating motion was performed for 1 minute at a speed of 1000 times per minute,
    An absorbent sheet, wherein the superabsorbent polymer does not come off from the absorbent sheet.
13. The absorbent sheet according to any one of claims 1 to 12,
    The absorbent sheet is divided into regions having a length of 40 mm in the vertical direction and a length of 40 mm in the horizontal direction, and a region in which the absorbent core exists in the entire region is defined as a divided region, When the weight of each divided area is measured,
    The absorbent sheet, wherein the CV value of the variation in weight of the divided regions is 10% or less.
14. having a longitudinal direction, a transverse direction and a thickness direction,
    an absorbent core comprising liquid-absorbent fibers and superabsorbent polymers;
    a liquid-permeable surface sheet arranged on the front side in the thickness direction relative to the absorbent core;
    a back sheet disposed on the back side in the thickness direction of the absorbent core;
    A method for manufacturing an absorbent sheet having
    A continuum of the top sheet continuing in the conveying direction, a continuum of the absorbent cores continuing in the conveying direction, and a continuum of the back sheet continuing in the conveying direction are laminated while being conveyed in the conveying direction. forming a continuum of laminated bodies;
    While conveying the continuum of laminates in the conveying direction, the continuum of laminates is cut so that the length of the continuum of laminates in the conveying direction corresponds to the length of the absorbent sheet in the longitudinal direction or the lateral direction. process and
    A method for producing an absorbent sheet, comprising:

Images