JP2015042477A - Liquid absorption sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid absorption sheet having high water absorption speed.SOLUTION: A liquid absorption sheet 1 comprises: a cardboard layer 10 (first cardboard layer); a cardboard layer 20 (second cardboard layer); and a polymer layer 30 (first polymer layer). The cardboard layers 10 and 20 are formed of cardboard. The polymer layer 30 is disposed between the cardboard layers 10 and 20. The polymer layer 30 includes a water absorption polymer.

Description

  The present invention relates to a liquid-absorbing sheet that absorbs liquid such as human or animal excrement.

  Patent Document 1 describes a pet sheet that is a kind of liquid-absorbing sheet. In this pet sheet, an absorbent layer is provided between the top sheet and the back sheet. The top sheet is a liquid-permeable sheet that allows liquid such as urine to pass through, and is composed of a nonwoven fabric. The back sheet is a liquid-impervious or water-repellent sheet that prevents or suppresses permeation of liquid such as urine, and is formed of a resin film. The absorbent layer is composed of a mixture of a water-absorbing polymer and pulp.

JP 2013-128453 A

  The urine excreted in the pet sheet described above reaches the absorption layer through the surface sheet, and is absorbed by the water-absorbing polymer and pulp in the absorption layer. However, the water-absorbing polymer has a lower water absorption rate than pulp and paper. This is a factor that decreases the water absorption rate of the absorbent layer and, consequently, the water absorption rate of the entire pet sheet.

  The present invention has been made in view of the above problems, and an object thereof is to provide a liquid-absorbing sheet having a high water absorption rate.

  The liquid-absorbing sheet according to the present invention is provided between a first cardboard layer made of cardboard, a second cardboard layer made of cardboard, and the first cardboard layer and the second cardboard layer. And a first polymer layer containing a polymer (including a superabsorbent polymer; the same applies hereinafter).

  The liquid to be treated by the liquid absorbent sheet is absorbed in the first cardboard layer prior to absorption in the first polymer layer. Then, the liquid that has not been absorbed by the first cardboard layer is absorbed by the water-absorbing polymer in the first polymer layer. In this way, prior to absorption by the water-absorbing polymer having a relatively low water absorption rate, absorption by paper (thick paper) having a relatively high water absorption rate is performed, thereby suppressing a decrease in the water absorption rate of the entire liquid-absorbing sheet. be able to.

  According to the present invention, a liquid absorbent sheet having a high water absorption rate is realized.

It is a schematic diagram which shows 1st Embodiment of the liquid absorbing sheet by this invention. FIG. 2 is a plan view of a cardboard layer in the liquid absorbent sheet of FIG. 1. It is a schematic diagram which shows 2nd Embodiment of the liquid absorbing sheet by this invention. It is a schematic diagram which shows 3rd Embodiment of the liquid absorbing sheet by this invention. It is a schematic diagram which shows the modification of the liquid absorbing sheet of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted.
(First embodiment)

  FIG. 1 is a schematic view showing a first embodiment of a liquid absorbent sheet according to the present invention. The liquid absorbent sheet 1 is a sheet that absorbs liquid such as urine, and is a cardboard layer 10 (first cardboard layer), a cardboard layer 20 (second cardboard layer), and a polymer layer 30 (first polymer layer). Layer).

  The cardboard layer 10 and the cardboard layer 20 are made of cardboard. The cardboard layer 10 and the cardboard layer 20 have substantially the same size and shape. In the present embodiment, the shapes of the cardboard layer 10 and the cardboard layer 20 are rectangular in plan view. The cardboard layer 10 and the cardboard layer 20 are opposed to each other with the polymer layer 30 interposed therebetween. The cardboard layer 10 and the cardboard layer 20 are bonded to each other at the edge. As a result, the polymer layer 30 is confined between the cardboard layer 10 and the cardboard layer 20.

  The thickness of the cardboard constituting the cardboard layer 10 and the cardboard layer 20 (that is, the thickness of each cardboard layer 10, 20) is, for example, 2 mm or more and 6 mm or less. The cardboard preferably contains neither glue nor adhesive. Moreover, as a material of cardboard, for example, waste materials such as paper sludge and waste paper can be used. In that case, the main material of cardboard is preferably paper sludge. Here, the main material of cardboard refers to a material having the highest weight ratio in the entire material constituting the cardboard.

  When using waste materials, for example, cardboard can be obtained as follows. That is, the waste material dissolved in water is made up with a wire mesh, dried, and then rolled up. At this time, the thickness of the obtained cardboard can be adjusted by repeating the papermaking. As the cardboard, ready-made cardboard may be used.

  The cardboard layer 10 constitutes the surface of the liquid absorbent sheet 1 (the surface that directly receives the liquid to be processed). The cardboard layer 20 constitutes the back surface of the liquid absorbent sheet 1. As shown in FIG. 2, a cut line L <b> 1 for easily dividing the liquid absorbent sheet 1 into a plurality of portions is formed at positions of both the thick paper layer 10 and the thick paper layer 20 facing each other. The cut line L1 is a perforation, for example. In the present embodiment, three cut lines L1 are formed at equal intervals parallel to the short side of the cardboard layer 10 (thick paper layer 20), and two cut lines L1 are formed at equal intervals parallel to the long side. .

  A surfactant may be added to the cardboard layer 10. The surfactant may be applied to the upper surface of the cardboard layer 10 (the surface of the liquid-absorbing sheet 1), or may be mixed in the cardboard layer 10. Further, the cardboard layer 10 may include tea husk or coffee husk. Similarly, the cardboard layer 20 may include tea husks or coffee husks. The weight ratio of the tea husk (the ratio of the weight of the tea husk to the total weight of the cardboard layer 10 or the cardboard layer 20) is preferably 3% or more and 30% or less. Further, the weight ratio of the coffee husk (the ratio of the weight of the coffee husk to the weight of the entire thick paper layer 10 or the thick paper layer 20) is preferably 2% or more and 20% or less.

  Returning to FIG. 1, the polymer layer 30 is provided between the cardboard layer 10 and the cardboard layer 20. The polymer layer 30 includes a water absorbing polymer. The polymer layer 30 may be made of only a water-absorbing polymer, or may be made of a mixture of the water-absorbing polymer and other materials. In the latter case, the water-absorbing polymer is preferably the main material of the polymer layer 30. Here, the main material of the polymer layer 30 refers to a material having the highest weight ratio in the entire material constituting the polymer layer 30.

  The effect of the liquid absorbing sheet 1 will be described. The liquid processed by the liquid absorbent sheet 1 is absorbed in the cardboard layer 10 prior to absorption in the polymer layer 30. The liquid that has not been absorbed by the cardboard layer 10 is absorbed by the water-absorbing polymer in the polymer layer 30. Thus, prior to absorption by the water-absorbing polymer having a relatively low water absorption rate, absorption by paper (thick paper) having a relatively high water absorption rate is performed, thereby reducing the water absorption rate of the entire liquid absorbent sheet 1. Can be suppressed. Therefore, the liquid absorbing sheet 1 having a high water absorption speed is realized.

  On the other hand, in the case of the pet sheet described in Patent Document 1 described above, absorption by the water-absorbing polymer and pulp is started at the same time. Therefore, the water absorption rate of the water-absorbing polymer is low. It will lead to a decrease in speed. Thus, when the water absorption speed of the whole sheet | seat becomes low, liquids, such as urine, will spread easily in a horizontal direction (in-plane direction of a sheet). In this case, the liquid is transmitted over a wide area of the sheet, that is, the used part of the sheet is enlarged, so that there is a problem that the life (replacement cycle) of the sheet is shortened. In this respect, according to the liquid-absorbing sheet 1 having a high water absorption speed, the liquid quickly moves in the vertical direction (direction perpendicular to the sheet surface), so that this problem can be avoided.

  In addition, the liquid that has not been absorbed by the polymer layer 30 is absorbed by the cardboard layer 20 below. For this reason, the liquid absorbing sheet 1 is excellent not only in the water absorption speed but also in the amount of water absorption. As described above, since the water absorption amount is high in the liquid absorbent sheet 1, it is possible to prevent the liquid from leaking to the outside without providing a waterproof sheet (liquid impervious or water repellent sheet). is there.

  Furthermore, since the thick paper layer 10 and the thick paper layer 20 are made of thick paper, they can absorb more liquid than a layer made of ordinary paper. Further, since the thick paper is higher in rigidity than ordinary paper, there is an advantage that it is easy to maintain the shapes of the thick paper layer 10 and the thick paper layer 20, and thus the shape of the entire liquid absorbent sheet 1. For this reason, even if it is a case where the water absorbing polymer in the polymer layer 30 expand | swells by water absorption, the shape change of the liquid absorbing sheet 1 can be suppressed small. From the viewpoint of obtaining such a high water absorption and rigidity, the thickness of the cardboard is preferably 2 mm or more. At the same time, the thickness of the cardboard is preferably 6 mm or less so that it can be formed relatively easily.

  The liquid absorbent sheet 1 having such characteristics can be suitably used as a pet sheet. Specifically, the liquid-absorbing sheet 1 is used, for example, in a state of being laid in a pet toilet (in the case of a two-stage toilet, the lower stage).

  Further, the cardboard layer 10 and the cardboard layer 20 constitute the front surface and the back surface of the liquid absorbent sheet 1, respectively. That is, no other layer is provided on either the upper side of the cardboard layer 10 (opposite side of the polymer layer 30) or the lower side of the cardboard layer 20 (opposite side of the polymer layer 30). By setting it as this simple structure, the manufacturing cost of the liquid absorbing sheet 1 can be restrained low.

  The cardboard layer 10 and the cardboard layer 20 are both made of cardboard and have the same size and shape. Thereby, since it is not necessary to prepare the thick paper layer 10 and the thick paper layer 20 separately, manufacture of the liquid absorption sheet 1 becomes easy.

  When a surfactant is added to the cardboard layer 10, the hydrophilicity of the cardboard layer 10 is increased, so that the liquid absorption by the cardboard layer 10 is promoted.

  When the cardboard layer 10 contains tea husks or coffee husks, the generation of malodor from the liquid-absorbing sheet 1 that has absorbed the liquid can be suppressed by the deodorizing action of the tea husks or coffee husks. The same applies to the case where the cardboard layer 20 includes tea husk or coffee husk.

  A cut line L1 is formed in the thick paper layer 10 and the thick paper layer 20 (FIG. 2). The used part can be easily separated from the liquid absorbent sheet 1 by dividing along the cut line L1. Note that the cut line L1 may be formed only on one of the cardboard layer 10 and the cardboard layer 20. Moreover, it is not essential to form the cut line L1.

  When the polymer layer 30 is composed only of the water-absorbing polymer, the liquid-absorbing sheet 1 can be realized with a simple configuration in which the water-absorbing polymer (polymer layer 30) is sandwiched between two cardboards (the cardboard layer 10 and the cardboard layer 20). The manufacturing cost of the liquid absorbent sheet 1 can be kept low.

When paper sludge is used as the cardboard material constituting the cardboard layer 10 and the cardboard layer 20, the material procurement cost can be reduced, and the manufacturing cost of the liquid absorbent sheet 1 can be reduced. When paper sludge is used as the main material, the cost reduction effect becomes significant. Further, when the cardboard does not contain a binder (glue or adhesive), further cost reduction can be achieved.
(Second Embodiment)

  FIG. 3 is a schematic view showing a second embodiment of the liquid absorbent sheet according to the present invention. The liquid absorbent sheet 2 is a sheet that absorbs liquid, and includes a cardboard layer 40 (third cardboard layer) in addition to the cardboard layer 10, the cardboard layer 20, and the polymer layer 30. The cardboard layer 10, the cardboard layer 20, and the polymer layer 30 are as described in the first embodiment.

  The cardboard layer 40 is provided between the cardboard layer 10 and the polymer layer 30. The cardboard layer 40 is made of cardboard similar to the cardboard layer 10 and the cardboard layer 20. The size and shape of the cardboard layer 40 are substantially the same as those of the cardboard layer 10 and the cardboard layer 20. The cardboard layer 40 faces the cardboard layer 20 with the polymer layer 30 in between. The upper and lower surfaces of the cardboard layer 40 are bonded to the cardboard layer 10 and the cardboard layer 20 at the edges, respectively. Thus, the polymer layer 30 is confined between the cardboard layer 40 and the cardboard layer 20. Similar to the cardboard layer 10 and the cardboard layer 20, the cardboard layer 40 may include tea husk or coffee husk.

The effect of the liquid absorbing sheet 2 will be described. In the liquid absorbent sheet 2, two cardboard layers (the cardboard layer 10 and the cardboard layer 40) are provided above the polymer layer 30 (the surface side of the liquid absorbent sheet 1). For this reason, compared with the liquid absorbent sheet 1, higher water absorption and rigidity can be obtained. Further, even when pressure is applied to the liquid absorbent sheet 1 after absorbing the liquid (for example, when a pet rides on the liquid absorbent sheet 1), the liquid oozes out from the liquid absorbent sheet 1. Can be prevented. Other effects of the liquid absorbent sheet 2 are the same as those of the liquid absorbent sheet 1.
(Third embodiment)

  FIG. 4 is a schematic view showing a third embodiment of the liquid absorbent sheet according to the present invention. The liquid absorbing sheet 3 is a sheet that absorbs liquid, and includes a polymer layer 50 (second polymer layer) in addition to the cardboard layer 10, the cardboard layer 20, the polymer layer 30, and the cardboard layer 40. The cardboard layer 10, the cardboard layer 20, the polymer layer 30, and the cardboard layer 40 are as described in the first embodiment and the second embodiment.

  The polymer layer 50 is provided between the cardboard layer 10 and the cardboard layer 40. The polymer layer 50 includes a water absorbing polymer. The amount of the water-absorbing polymer contained in the polymer layer 50 is preferably smaller than the amount of the water-absorbing polymer contained in the polymer layer 30. The polymer layer 50 may be made of only the water-absorbing polymer, or may be made of a mixture of the water-absorbing polymer and other materials. In the latter case, the water-absorbing polymer is preferably the main material of the polymer layer 50. Here, the main material of the polymer layer 50 refers to a material having the highest weight ratio in the entire material constituting the polymer layer 50.

  The effect of the liquid absorbing sheet 3 will be described. In the liquid absorbing sheet 3, two polymer layers (polymer layer 30 and polymer layer 50) are provided. For this reason, compared with the liquid absorbing sheet 1 and the liquid absorbing sheet 2, a higher water absorption is obtained.

  When two polymer layers are provided in this way, the upper polymer layer (polymer layer 50) has not only a function of absorbing a large amount of liquid, but also the liquid in the lower layer (layer below the cardboard layer 40). The ability to move quickly is also expected. In this respect, if the amount of the water-absorbing polymer contained in the polymer layer 50 is too large, the function of quickly moving the liquid is hindered. On the other hand, what is expected exclusively from the lower polymer layer (polymer layer 30) is a function of absorbing a large amount of liquid. For this reason, the amount of the water-absorbing polymer contained in the polymer layer 50 is preferably smaller than the amount of the water-absorbing polymer contained in the polymer layer 30. Other effects of the liquid absorbent sheet 3 are the same as those of the liquid absorbent sheet 1 and the liquid absorbent sheet 2.

  The liquid absorbent sheet according to the present invention is not limited to the above embodiment, and various modifications are possible. For example, as shown in FIG. 5, the liquid absorbent sheet 1 may be embossed. In the same figure, the upper surface of the cardboard layer 10 (surface of the liquid absorbent sheet 1) and the lower surface of the cardboard layer 20 (back surface of the liquid absorbent sheet 1) are formed with unevenness by embossing. Accordingly, the polymer layer 30 is deformed in a wave shape.

  By embossing in this way, it is possible to suppress the water-absorbing polymer from moving and being unevenly distributed in the polymer layer 30. Moreover, when a used part is cut off from the liquid absorbent sheet 1, it is possible to suppress spilling of the water absorbent polymer from the cut. Furthermore, since the liquid to be processed accumulates in the concave portion on the upper surface of the cardboard layer 10, it is possible to prevent the liquid from spreading in the lateral direction. Needless to say, the liquid absorbent sheet 2 and the liquid absorbent sheet 3 may be embossed in the same manner as the liquid absorbent sheet 1.

DESCRIPTION OF SYMBOLS 1 Liquid absorbing sheet 2 Liquid absorbing sheet 3 Liquid absorbing sheet 10 Cardboard layer (1st cardboard layer)
20 Cardboard layer (second cardboard layer)
30 polymer layer (first polymer layer)
40 Cardboard layer (third cardboard layer)
50 polymer layer (second polymer layer)
L1 cut line

Claims (17)

A first cardboard layer of cardboard;
A second cardboard layer of cardboard;
A first polymer layer provided between the first cardboard layer and the second cardboard layer and comprising a water-absorbing polymer;
A liquid-absorbing sheet comprising: In the liquid-absorbing sheet according to claim 1,
A liquid-absorbing sheet comprising a third cardboard layer made of cardboard provided between the first cardboard layer and the first polymer layer. In the liquid-absorbing sheet according to claim 2,
A liquid-absorbing sheet comprising a second polymer layer provided between the first cardboard layer and the third cardboard layer and containing a water-absorbing polymer. In the liquid-absorbing sheet according to claim 3,
The liquid absorbing sheet, wherein the amount of the water absorbing polymer contained in the second polymer layer is smaller than the amount of the water absorbing polymer contained in the first polymer layer. In the liquid absorption sheet in any one of Claims 1 thru | or 4,
The liquid absorbent sheet is an embossed liquid absorbent sheet. In the liquid absorption sheet in any one of Claims 1 thru | or 5,
The first cardboard layer constitutes the surface of the liquid absorbent sheet,
The second cardboard layer is a liquid absorbent sheet constituting the back surface of the liquid absorbent sheet. The liquid-absorbing sheet according to claim 6,
A liquid-absorbing sheet in which a cut line is formed on at least one of the first cardboard layer and the second cardboard layer for easily dividing the liquid-absorbing sheet into a plurality of sheets. In the liquid-absorbing sheet according to claim 7,
The cutoff line is a liquid-absorbing sheet formed at a position where both of the first cardboard layer and the second cardboard layer face each other. In the liquid absorption sheet in any one of Claims 6 thru | or 8,
A liquid-absorbing sheet in which a surfactant is added to the first cardboard layer. In the liquid absorption sheet in any one of Claims 1 thru | or 9,
A liquid-absorbing sheet in which at least one of the first cardboard layer or the second cardboard layer contains tea husk. In the liquid-absorbing sheet according to claim 10,
The liquid absorbent sheet, wherein a weight ratio of the tea husk contained in the first cardboard layer or the second cardboard layer is 3% or more and 30% or less. The liquid-absorbent sheet according to any one of claims 1 to 11,
A liquid-absorbing sheet in which coffee husk is contained in at least one of the first cardboard layer or the second cardboard layer. The liquid-absorbing sheet according to claim 12,
The liquid absorbent sheet, wherein a weight ratio of the coffee husk contained in the first cardboard layer or the second cardboard layer is 2% or more and 20% or less. In the liquid absorption sheet in any one of Claims 1 thru | or 13,
The first polymer layer is a liquid-absorbing sheet made only of a water-absorbing polymer. In the liquid absorption sheet in any one of Claims 1 thru | or 14,
The main material of the cardboard is a liquid absorbing sheet which is paper sludge. In the liquid absorption sheet in any one of Claims 1 thru | or 15,
The cardboard does not contain any glue or adhesive. The liquid-absorbent sheet according to any one of claims 1 to 16,
The cardboard has a thickness of 2 mm or more and 6 mm or less.

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