JP3357518B2 - Absorbent sheet, method for producing the same, and absorbent article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a sanitary napkin,
Absorbent sheet particularly preferably used for hygiene pad, disposable diaper, medical pad, breast milk pad, drip sheet, kitchen absorbent sheet, household cleaning sheet, pet undersheet, etc., method for producing the same, and absorption using the same It is related to a sexual article.

[0002]

BACKGROUND OF THE INVENTION Various methods are known for obtaining superabsorbent sheets by immobilizing a superabsorbent polymer in an absorbent structure. For example, U.S. Pat. No. 3,070,095 discloses, as shown in FIG.
Sprinkling the superabsorbent polymer 16 on the tissue 30,
It discloses that after another tissue 31 is laminated thereon, the superabsorbent polymer is pressed into the tissue by pressing with a roller. However, in this method,
The superabsorbent polymer is only fixed in layers between the tissue layers, and a large amount of the superabsorbent polymer cannot be fixed. Therefore, when such an absorbent sheet is used, for example, as an absorbent body of an absorbent article, the highly absorbent 16 polymer becomes the tissue 30,
Separating from the tissue 31, a space may be created between the tissues 30, 31 and the liquid may stay there.

[0003] US Patent No. 3,670,731 discloses that after spraying a superabsorbent polymer between two paper layers,
It discloses embossing to secure the superabsorbent polymer within the embossed cavity. However, this method also has the same drawbacks as the above-described roller compression method.

US Pat. No. 3,670,731 discloses that a superabsorbent polymer is sprayed between two sheets of crepe paper and then quilted to hold the superabsorbent polymer in place. Has been disclosed. However, this method also has the disadvantage that large amounts of superabsorbent polymers cannot be fixed.

Also, Japanese Patent Publication No. 59-26767, Japanese Patent Application Laid-Open No. 54-123293 and Japanese Patent Application Laid-Open No. 54-141
No. 099 discloses that, after spraying steam or spraying water on a tissue to moisten the tissue, a high-absorbency polymer is sprayed, and the high-absorbency polymer is provided with tackiness, so that the tissue is interposed between the tissues. It is disclosed to fix superabsorbent polymers. According to this method,
Although the superabsorbent polymer can be fixed to some extent, it cannot be completely prevented from falling off, and the fixing amount is still insufficient. In addition, when a liquid is absorbed, the superabsorbent polymer swells in a layered form, and in some cases, absorption inhibition may occur due to gel blocking or the like.

[0006] Also, Japanese Patent Application Laid-Open No. 61-132,976 discloses
In the papermaking process, a highly absorbent poly
After spraying the
A method for producing absorbent paper containing
You. According to this method, a certain amount of superabsorbent polymer
Can be fixed in paper, but the fixed amount is at most 10 g / m
^TwoDegree, and it is not enough. Also,
In the absorbent sheet that has been treated,
Because of the presence of superabsorbent polymer,
The absorptive polymer is driven by dynamic actions such as friction
It has the disadvantage of easily falling off.

Further, a method is also known in which a hot-melt adhesive is applied to the entire surface of a tissue or the like, and the superabsorbent polymer is fixed by the adhesive. According to this method, the superabsorbent polymer can be reliably fixed. However, since the hot melt adhesive covers most of the surface of the superabsorbent polymer, swelling inhibition of the superabsorbent polymer and inhibition of liquid absorption occur.

As another method of immobilizing a superabsorbent polymer using a hot melt adhesive, there is a method of applying a hot melt adhesive in a spiral shape. According to this method, the swelling inhibition and the absorption inhibition are small, and the highly absorbent polymer can be fixed efficiently. However, applying the hot melt adhesive spirally complicates the manufacturing process and equipment. Further, since a large amount of the superabsorbent polymer is fixed in a layer, gel blocking of the superabsorbent polymer occurs when the liquid is absorbed, and swelling of the liquid is inhibited.

On the other hand, an absorbent sheet using wood pulp manufactured by a dry method is also known. In such an absorbent sheet, if an attempt is made to increase the sheet strength by using a chemical binder, a high content synthetic pulp, a low melting point synthetic fiber, or the like, the absorbent sheet becomes hydrophobic and the absorption rate is reduced. When the sheet strength is low, there is a disadvantage that when absorbing liquid, the superabsorbent polymer swells and breaks the absorbent sheet to protrude outward. In addition, crepe paper may be laminated in order to increase the surface strength of the absorbent sheet, but in this case, there is a problem that the cost is increased.
In addition, in each case, the superabsorbent polymer is insufficiently fixed to the wood pulp, and the problem that the superabsorbent polymer is likely to fall off is not improved. Further, there is a problem that when the absorbent sheet is strongly compressed, the liquid absorption rate is unavoidably reduced.

In addition to the above-mentioned absorbent sheet, there is also known a method in which a superabsorbent polymer is directly polymerized on a nonwoven fabric serving as a base material and fixed on the nonwoven fabric to obtain an absorbent sheet. However, when a nonwoven fabric composed of hydrophilic fibers is used as the nonwoven fabric, the superabsorbent polymer obtained as a result of the polymerization does not become particles but is fixed almost uniformly to the entire nonwoven fabric, so that the liquid absorption amount However, there is a drawback that is reduced. On the other hand, when a nonwoven fabric made of hydrophobic fibers is used as the nonwoven fabric, unlike the nonwoven fabric made of the above hydrophilic fibers, the superabsorbent polymer obtained as a result of polymerization becomes particulate, Has the disadvantage that the liquid absorption rate is low because of its hydrophobicity. Moreover, in these methods, the unreacted monomer remains unavoidable, so that the use of the absorbent sheet is limited from the viewpoint of safety of the monomer to the human body.

Accordingly, an object of the present invention is to provide an absorbent sheet in which a superabsorbent polymer is securely fixed without impairing the original absorption characteristics of the superabsorbent polymer.

Another object of the present invention is to provide an absorbent sheet which can absorb liquid very smoothly without leaving it on the surface, guide the liquid quickly to the entire superabsorbent polymer, and can effectively fix the liquid. Is to do.

[0013] Another object of the present invention is to provide an absorbent sheet capable of exhibiting the original absorption characteristics of a superabsorbent polymer without causing gel blocking of the superabsorbent polymer even when liquid is repeatedly absorbed. is there.

Another object of the present invention is to provide a method for easily producing the above-mentioned absorbent sheet.

It is a further object of the present invention to provide an absorbent article having the above absorbent sheet and having a high absorption performance.

[0016]

In order to achieve the above object,
The present inventors have conducted intensive studies and found that, in a state where the fibers constituting the absorbent sheet were moistened, the superabsorbent polymer was buried in the space formed between the fibers, whereby the superabsorbent polymer was formed. It has been found that it can be immobilized in a large amount and gel blocking of the superabsorbent polymer can be effectively prevented.

The present invention has been made based on the above findings, and is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers. The fiber aggregate and the fiber web are integrated with each other, and the fiber aggregate has an absorbent surface and the absorbent surface side contains the superabsorbent polymer. And average fiber length of 1 to 20 mm and fiber roughness of 0.3 m
g / m or more of bulky cellulose fibers, and the fiber web has a bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and an average fiber length of 0.02 to 0.02. Including the 0.5 mm hydrophilic fine fibers, the proportion of the hydrophilic fine fibers on one side is higher than the proportion on the other side, and the proportion of the hydrophilic fine fibers. Is adjacent to the fiber assembly on the lower surface side, and the superabsorbent polymer is contained in the interior of the absorbent sheet and adheres to fibers constituting the absorbent sheet. The above object has been achieved by providing an absorbent sheet (hereinafter, referred to as "first absorbent sheet").

The present invention also provides a preferred method for producing the absorbent sheet, wherein the bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and an average fiber length of 0.02 to 0 The wet fibrous web, comprising 0.5 mm of hydrophilic fine fibers, wherein the proportion of the hydrophilic fine fibers on one side is higher than the proportion on the other side. A highly absorbent polymer is sprayed on the surface where the proportion of fine fibers is low, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg /
It is intended to provide a method for producing an absorbent sheet, which comprises a step of laminating a fiber aggregate mainly composed of bulky cellulose fibers having a length of at least m and drying and integrating them.

Further, the present invention provides a preferable absorbent article using the above-mentioned absorbent sheet, as a liquid absorbent surface layer,
In the absorbent article having a liquid-retentive absorbing layer and a liquid-impermeable leak-proof layer, at least the superabsorbent polymer and the bulkiness are provided on the surface layer or the absorbent layer or on the absorbent layer side of the leak-proof layer. Absorbent sheet containing cellulose fibers and hydrophilic fine fibers is included, and the absorbent sheet is composed of a fiber aggregate and a fiber web, and the fiber aggregate and the fiber web are integrated. And
The fiber aggregate has an absorbent surface and does not contain the superabsorbent polymer on the absorbent surface side, and has a bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Mainly, the above fiber web is
A bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and an average fiber length of 0.02 to
Including the 0.5 mm hydrophilic fine fibers, the proportion of the hydrophilic fine fibers on one side is higher than the proportion on the other side, and the proportion of the hydrophilic fine fibers. Is adjacent to the fiber assembly on the lower surface side, and the superabsorbent polymer is contained in the interior of the absorbent sheet and adheres to fibers constituting the absorbent sheet. To provide an absorbent article.

The present invention also relates to an absorbent sheet containing at least a super absorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, wherein the absorbent sheet comprises a fiber aggregate and a fiber web. In addition, the fiber aggregate and the fiber web are integrated, and the fiber aggregate has an absorbent surface and does not contain the superabsorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 1. 20m
m, comprising a bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the hydrophilic fine fibers on one side thereof Is higher than the existing ratio on the other surface side, the fiber web has an average fiber length of 1 to 20 mm.
In the main body is a bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more, and is adjacent to the fiber aggregate on the surface side where the proportion of the hydrophilic fine fibers in the fiber aggregate is high, An absorbent sheet (hereinafter, referred to as a "second absorbent sheet"), wherein the superabsorbent polymer is contained in the interior of the absorbent sheet and is adhered to fibers constituting the absorbent sheet. To achieve the above object.

The present invention also provides a preferred method for producing the above-mentioned absorbent sheet, which comprises a wet fiber web mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Is sprayed with a superabsorbent polymer, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.
It contains bulky cellulose fibers of 3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one surface side is the other. A fiber aggregate higher than the abundance ratio on the surface side, the surface side where the hydrophilic fine fiber abundance ratio is high and the fiber web are overlapped so that they are adjacent to each other, and these are dried and integrated. It is intended to provide a method for producing an absorbent sheet, characterized by comprising:

Further, the present invention provides a preferable absorbent article using the above-mentioned absorbent sheet, as a liquid absorbent surface layer,
In the absorbent article having a liquid-retentive absorbing layer and a liquid-impermeable leak-proof layer, at least the superabsorbent polymer and the bulkiness are provided on the surface layer or the absorbent layer or on the absorbent layer side of the leak-proof layer. Absorbent sheet containing cellulose fibers and hydrophilic fine fibers is included, and the absorbent sheet is composed of a fiber aggregate and a fiber web, and the fiber aggregate and the fiber web are integrated. And
The fiber aggregate has an absorbent surface and does not contain the superabsorbent polymer on the absorbent surface side, and a bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more; The fiber web, comprising hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, wherein the proportion of the hydrophilic fine fibers on one side is higher than the proportion on the other side. Is the average fiber length 1
２０20 mm, mainly comprising bulky cellulose fibers having a fiber roughness of 0.3 mg / m or more, and adjacent to the fiber aggregate on the surface side where the proportion of the hydrophilic fine fibers in the fiber aggregate is high. In addition, the present invention provides an absorbent article characterized in that the superabsorbent polymer is contained in the interior of the absorbent sheet and adheres to fibers constituting the absorbent sheet.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first and second absorbent sheets of the present invention will be described below in detail with reference to the drawings. Here, FIG. 1 is a schematic diagram showing a cross section of the first absorbent sheet of the present invention, and FIG. 2 is a schematic diagram showing a cross section of the second absorbent sheet of the present invention.

First, the first absorbent sheet of the present invention will be described. As shown in FIG. 1, the first absorbent sheet 100 of the present invention is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers. , Fiber assembly 105
And a fiber web 108. The fiber aggregate 105 has the absorbent surface 102 and does not include a superabsorbent polymer on the absorbent surface 102 side. The fiber aggregate 105 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m.
It is formed mainly of bulky cellulose fibers 12 of g / m or more.

On the other hand, as shown in FIG. 1, the fiber web 108 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m.
g / m or more of bulky cellulose fibers 12 and hydrophilic fine fibers 14 having an average fiber length of 0.02 to 0.5 mm. Is higher than the existence ratio on the surface side. Then, the fiber web 108 has the fiber aggregate 105 on the surface side where the proportion of the hydrophilic fine fibers is low.
Is adjacent to

As shown in FIG. 1, the fiber aggregate 105 and the fiber web 108 are integrated. Further, the superabsorbent polymer 106 is contained in the interior of the absorbent sheet 100 and adheres to fibers constituting the absorbent sheet 100.

As described above, the first absorbent sheet 1 of the present invention
No. 00 is one of the features that it has an integrated structure including the fiber aggregate 105 and the fiber web 108 and the superabsorbent polymer 106 contained therein. More specifically, the first absorbent sheet 100 of the present invention provides a mechanical entanglement between the fibers constituting the fiber aggregate 105 and the fibers constituting the fiber web 108, and hydrogen bonding (and a strong auxiliary). And the fiber assembly 10 by heat fusion or the like.
5 and the fiber web 108 are integrated. By having such a structure, the superabsorbent polymer 106
Is securely fixed, and can be prevented from falling off.
Moreover, the permeability and diffusivity of the liquid absorbed from the absorbing surface 102 are further improved, and the liquid reaches the superabsorbent polymer 106 smoothly. In addition, gel blocking of the superabsorbent polymer 106 that has absorbed the liquid is also suppressed. Therefore, the first absorbent sheet 100 of the present invention has a completely different structure from the conventional absorbent sheet (FIG. 12) in which the superabsorbent polymer is sandwiched between two sheets of absorbent paper (FIG. 12). Conventional absorbent sheets are two plies,
The first absorbent sheet 100 of the present invention is a single sheet). Such integration is preferably achieved by lamination using wet papermaking, as described later.

Next, the fiber web 108 in the first absorbent sheet 100 of the present invention will be described. In the present invention, the term "fiber web" means that, in the wet state before spraying the superabsorbent polymer, the constituent fibers are not restrained at all or are slightly restrained by hydrogen bonding, mechanical entanglement and frictional force. It means that the fibers have a very high degree of freedom, and after drying, the constituent fibers are strongly constrained to each other to take the form of a sheet.

The fiber web 108 is in a wet state before the superabsorbent polymer 106 is sprayed, and it is important that the fibers constituting the fiber web 108 have an extremely high degree of freedom. . By dispersing the superabsorbent polymer 106 on the fiber web 108 in such a state, the superabsorbent polymer 106 is embedded and fixed in the fiber web 108. That is, the superabsorbent polymer 106 is three-dimensionally dispersed in the fiber web 108. Further, the fiber web 108 has such a strength that the superabsorbent polymer 106 does not precipitate on the surface of the first absorbent sheet 100 after the fiber web 108 and the fiber aggregate 105 are integrated. It is also important that For this purpose, the fiber web 108 is preferably dried by itself to form a sheet, and the wet tensile strength measured by JIS-P-8113 is preferably 50 g or more, and more preferably 100 g or more. Is more preferred. In order to give the fiber web 108 a tensile strength when wet, the fiber web 10
It is preferable to blend a hot-melt adhesive fiber described later or a strong auxiliary agent (paper strength reinforcing agent) described later.

The basis weight of the fiber web 108 is preferable.
Or 10g / m^Two~ 200g / m ^TwoAnd more preferred
Or 10g / m^Two~ 100g / m^TwoAnd more preferred
Or 20g / m^Two~ 80g / m^TwoIt is. The above grammage is
10g / m^TwoLess than the above, the superabsorbent polymer 10
6 when the superabsorbent polymer 106 is swelled.
There is a possibility that the projection 108 may protrude and fall off. one
On the other hand, the basis weight is 200 g / m^TwoOver the fiber web
The density is too high, and the first absorbent sheet 100 is hard
Overlying the superabsorbent polymer 106 in three dimensions.
Cannot be set, liquid permeability is poor,
May have a bad fit,
Preferably.

The fiber web 108 will be described in more detail. The fiber web 108 has an average fiber length of 1 to 20 mm.
Containing bulky cellulose fibers having a fiber roughness of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm. Is higher than the existing ratio on the other surface side. As a result, the surface side where the proportion of the hydrophilic fine fibers is low has excellent liquid absorption speed and local liquid absorption, and also has high liquid permeability. On the other hand, the surface side where the proportion of the hydrophilic fine fibers is high is excellent in liquid diffusivity because the hydrophilic fine fibers have a high surface area. Therefore, it is possible to quickly diffuse the liquid that has passed through the surface having the lower percentage of the hydrophilic fine fibers. As described above, the fiber web 108 has both the property of absorbing and transmitting liquid and the property of diffusing liquid, though it has a single structure. In addition, the fiber web 108 has the fiber aggregate 1 on the surface side where the proportion of the hydrophilic fine fibers is low.
As described above, it is adjacent to 05. Less than,
For the sake of simplicity, among the surfaces of the fiber web 108, the surface having the lower percentage of the hydrophilic fine fibers is referred to as a first surface,
The surface having the higher percentage of the hydrophilic fine fibers is referred to as a second surface.

As shown in FIG. 1, the fiber web 108
However, since the bulky cellulose fiber is mainly used from the first surface to the vicinity of the first surface, it has a function of absorbing liquid quickly and allowing liquid to permeate the second surface quickly. That is, this region mainly functions as an “absorption / transmission layer” for liquid. On the other hand, the second surface
Since the hydrophilic fine fibers are mainly used in the vicinity of the surface, the liquid has a function of quickly diffusing the liquid transmitted from the first surface. That is, this region mainly functions as a “diffusion layer” of the liquid. As described above, the fiber web 108 is characterized by having both the absorption / transmission layer and the diffusion layer in a single structure. As a result, the liquid web has high liquid absorbability, and is extremely dry after liquid absorption. Yes (Sarat feeling).

As described above, there is a large difference in liquid diffusivity between the first surface and the second surface. That is, the liquid is rapidly diffused on the second surface side (diffusion layer) mainly composed of the hydrophilic fine fibers. On the other hand, on the first surface side (absorptive and transmissive layer) mainly composed of the bulky cellulose fibers, liquid absorption and permeation are quick, but liquid diffusion is not so fast. That is, the fiber web 108 has a diffusion gradient with respect to the diffusion of the liquid in the thickness direction.

The proportion of the hydrophilic fine fibers in the fiber web 108 may be gradually increased from the first surface toward the second surface, but is increased stepwise from a certain thickness. It may be.

On the other hand, the bulky cellulose fibers may be present uniformly in the thickness direction of the fiber web 108, but are more preferably present in the absorbent sheet of the present invention than the second side. The existence ratio is higher on the one surface side. That is, in the thickness direction of the fiber web 108, it is preferable that the existence ratio of the bulky cellulose fiber has a gradient. The existence ratio is the second
It may increase gradually from the surface toward the first surface, or may increase stepwise at a certain thickness.

More specifically, the hydrophilic fine fibers are preferably formed at a depth of about 1/3 in the thickness direction from the second surface side of the fiber web 108, preferably about 5% based on the total amount thereof.
To about 70% by weight, more preferably about 10 to about 50% by weight
The diffusion layer is present and mainly composed of the hydrophilic fine fibers. On the other hand, at a depth of about 2/3 in the thickness direction from the first surface side of the fiber web 108, the bulky cellulose fiber is preferably about 60 to about 100% by weight, more preferably Preferably about 70 to about 9
7% by weight, and the absorption / transmission layer mainly composed of the bulky cellulose fiber is formed.

As described above, in the thickness direction of the fiber web 108, the distribution of the bulky cellulose fibers and the hydrophilic fine fibers may gradually increase, and the distribution may be stepwise at a certain thickness. May be increased. The fiber web 108 in which both the bulky cellulose fiber and the hydrophilic fine fiber have a gradient in their distribution in the thickness direction of the fiber web 108.
In the particularly preferred embodiment of the above, the liquid absorbability and liquid diffusivity can be more remarkably expressed.

The mixing ratio of the bulky cellulose fiber and the hydrophilic fine fiber in the fiber web 108 is not particularly limited, but the bulky cellulose fiber is based on 100 parts by weight of the fiber web. 50-97
It is preferably contained by weight, more preferably 70 to 95 parts by weight. If the compounding ratio of the bulky cellulose fiber is less than 50 parts by weight, the bulky network structure is insufficient, and a fiber web having both transmission and diffusion may not be obtained. When the compounding ratio exceeds 97 parts by weight, the compounding ratio of the hydrophilic fine fibers becomes low, and the diffusivity becomes insufficient.
It is preferable to be within the above range.

On the other hand, the hydrophilic fine fibers are preferably contained in an amount of 3 to 50 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of the fiber web. When the compounding ratio of the hydrophilic fine fibers is less than 3 parts by weight, the diffusibility becomes insufficient. When the compounding ratio of the hydrophilic fine fibers exceeds 50 parts by weight, the hydrophilicity on the first surface side is reduced. Since the mixing ratio of the fine fibers increases, and the permeability becomes insufficient, it is preferable to be within the above range.

Further, if necessary, heat-meltable adhesive fibers which are melted by heating and adhere to each other may be added to the fiber web 108. By adding such heat-meltable adhesive fibers, the structural stability of the fiber web 108 when wet can be maintained.

The heat-meltable adhesive fiber is preferably added in an amount of 2 to 30 parts by weight, more preferably 3 to 20 parts by weight, based on 100 parts by weight of the fiber web. When the addition amount is less than 2 parts by weight, the strength when the liquid is actually absorbed becomes insufficient, or the mixed state of the bulky cellulose fiber and the hydrophilic fine fiber in the fiber web 108 becomes insufficient. Undesirably, the diffusion gradient may not be maintained. On the other hand, if the addition amount exceeds 30 parts by weight, the hydrophilicity of the entire fiber web 108 decreases,
It is not preferable because the liquid absorption rate and the liquid diffusion ability may be insufficient.

Other optional components which can be added to the fiber web 108 include, for example, other pulp such as softwood pulp, hardwood pulp and straw pulp, and polyamine / epichlorohydrin resin as a strong auxiliary, dialdehyde starch, sponge And carboxymethylcellulose. These components are preferably 0 to 30 parts by weight based on 100 parts by weight of the fiber web.
Parts by weight, more preferably 0 to 20 parts by weight.

The thickness of the fiber web 108 is not particularly limited, but the thickness under a load of 2.5 g / m ² is 0.2 to ² mm.
And more preferably 0.2 to 1 mm. If the thickness is less than 0.2 mm, the fiber web may be too thin to achieve the respective functions of permeation and diffusion, and if the thickness exceeds 2 mm, smooth transmission of liquid such as permeation and diffusion may occur. Is less likely to occur, so it is preferable to be within the above range.

In a particularly preferred embodiment of the fiber web 108, the fiber web 108 contains 70 to 95 parts by weight of the bulky cellulose fiber and 5 to 5 parts by weight of the hydrophilic fine fiber based on 100 parts by weight of the fiber web. -30 parts by weight, and 2-30 parts by weight of the hot-melt adhesive fiber; and the basis weight is 10-200 g / m ² .

Next, the fiber web 108 is constructed.
The bulky cellulose fiber, the hydrophilic fine fiber, and the hot-melt adhesive fiber will be described.

First, the bulky cellulose fiber will be described. The bulky cellulose fiber has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3.
Any cellulose fiber may be used as long as it is at least mg / m and bulky. As cellulose fiber,
For example, natural cellulose such as wood pulp and cotton, and regenerated cellulose such as rayon and cupra can be used.
From the viewpoint of cost, wood pulp is preferably used, and coniferous kraft pulp is particularly preferably used.
One or more of these cellulose fibers can be used. The bulky cellulose fibers preferably have an average fiber length of 2 to 10 mm, and more preferably an average fiber length of 2 to 5 mm. Average fiber length is 1m
If it is less than m, the bulky network structure cannot be formed, and the hydrophilic fine fibers cannot pass between the bulky network structures as described later. If the average fiber length exceeds 20 mm, the dispersibility in water becomes worse, and a uniform network structure cannot be formed. In the present invention, “bulky fiber” refers to a fiber having a three-dimensional structure such as a twisted structure, a crimped structure, a bent and / or a branched structure, or an extremely thick fiber cross section (for example, having a fiber roughness of 0. 3 mg / m or more).

The bulky cellulose fiber has a fiber roughness of 0.3 mg / m or more. Fiber roughness of 0.3
When the amount is not less than mg / m, the cellulose fibers are accumulated in a bulky state, and the bulky network structure is formed. In addition, the movement resistance of the liquid is small, and the passing speed of the liquid is also increased. The bulky cellulose fiber has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg /
m or more, and the roundness of the fiber cross section is 0.5
When the value is １1, the above effect is further exhibited, which is more preferable.

In the present invention, the term “fiber roughness” refers to a fiber having a non-uniform fiber thickness, such as wood pulp.
It is used as a scale representing the thickness of the fiber. For example, a fiber roughness meter (FS-200, KAJANNI ELECTRONIC
S LTD.).

As described above, with respect to the fiber roughness, the bulky cellulose fiber preferably has a fiber roughness of 0.3 mg / m or more, and more preferably has a fiber roughness of 0.1 mg / m.
3 to 2 mg / m, and more preferable fiber roughness is 0.3
2-1 mg / m. Further, the roundness of the fiber cross section is more preferably 0.55 to 1.

Examples of cellulose fibers having a fiber roughness of 0.3 mg / m or more include softwood kraft pulp [Federal
"ALBACEL" (trade name) manufactured by Paper Board Co., and PT
"INDORAYON" (trade name) manufactured by Inti Indorayon Utama].

As described above, the bulky cellulose fiber preferably has a roundness of the fiber cross section of 0.5 to 1, and if the roundness is within this range, the bulky cellulose fiber will have a roundness within this range. The fibers are thick and round, and when formed into an aggregate, the cross-sectional structure of the aggregate becomes bulky, and since the fibers are not in close contact with each other, it is difficult for hydrogen bonding to occur, and the bulky structure can be maintained.

As described above, in the present invention, it is preferable to use wood pulp as the cellulose fiber. However, in general, the cross section of the wood pulp is flat due to delignification treatment, and almost all of its roundness is reduced. It is less than 0.5. In order to make the roundness of such wood pulp 0.5 or more, for example, wood pulp having a fiber roughness of 0.3 mg / m or more is subjected to mercerization treatment to swell the cross section of the wood pulp. Good. That is, the bulky cellulose fiber,
Mercerized pulp is also preferred.

As described above, the roundness of the fiber cross section is 0.5 to
As the cellulose fiber of No. 1, mercerized pulp having a roundness of 0.5 to 1 obtained by mercerizing wood pulp is preferable. Examples of commercially available mercerized pulp that can be used in the present invention include ITT Rayoni
"FILTRANIER" (trade name) manufactured by er Inc. and "PO
ROSANIER "(product name).

Other preferred examples of the bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more include cross-linking within and between molecules of the cellulose fiber. There is a crosslinked cellulose fiber obtained by the above method. Such a crosslinked cellulose fiber is preferable because it does not swell even when wet with a liquid, has little twist / set, and can maintain a bulky structure without a decrease in strength.

The method for crosslinking the cellulose fibers is not particularly limited, and examples thereof include a crosslinking method using a crosslinking agent. Examples of such crosslinking agents include N-methylol compounds such as dimethylol ethylene urea and dimethylol dihydroxyethylene urea; polycarboxylic acids such as citric acid, tricarballylic acid and butanetetracarboxylic acid; polyols such as dimethyl hydroxyethylene urea ;
A cross-linking agent for a polyglycidyl ether compound may be used. In particular, a crosslinking agent of a polycarboxylic acid or a polyglycidyl ether compound which does not generate formalin or the like harmful to the human body at the time of crosslinking is preferable.

The amount of the crosslinking agent used is preferably 0.2 to 20 parts by weight based on 100 parts by weight of the cellulose fiber. If the amount used is less than 0.2 parts by weight, the crosslink density of the cellulose fibers is low, so that the elastic modulus may be significantly reduced when wet. Since the cellulose fibers become too rigid and may become brittle when stress is applied, it is preferable to be within the above range.

In order to crosslink the above-mentioned cellulose fibers using the above-mentioned crosslinking agent, for example, an aqueous solution of the above-mentioned crosslinking agent to which a catalyst is added as necessary is impregnated with the above-mentioned cellulose fibers, and the aqueous solution of the crosslinking agent is designed. The cellulose fibers are dehydrated so as to have an adhesion amount, and then heated to a crosslinking temperature,
Alternatively, an aqueous solution of a crosslinking agent is sprayed on the cellulose fiber so as to have a designed adhesion amount by spraying or the like, and then heated to a crosslinking temperature to cause a crosslinking reaction.

As the above-mentioned crosslinked cellulose fibers, commercially available ones can also be used. As such a crosslinked cellulose fiber, "Hi" manufactured by Weyerhaeuser Paper Co.
gh Bulk Additive "(trade name).

Further preferred crosslinked cellulose fibers have an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg /
m or more, and a cross-linked cellulose fiber having a roundness of the fiber cross section of 0.5 to 1. Further, the crosslinked cellulose fibers of the mercerized pulp described above are also preferable.

Next, the hydrophilic fine fibers will be described. The hydrophilic fine fibers have a hydrophilic surface and an average fiber length of 0.02 to 0.5 mm, preferably 0.03 to 0.3 mm. If the average fiber length of the hydrophilic fine fibers is less than 0.02 mm, in a preferred method for producing the fiber web described below, the hydrophilic fine fibers pass through the papermaking wire, and the hydrophilic fiber Inability to deposit fine fibers. Further, when the average fiber length of the hydrophilic fine fibers exceeds 0.5 mm, in a preferred method for producing the fiber web described below, the hydrophilic fine fibers are formed by the bulky cellulose fibers. It cannot pass through the network structure and is not deposited on the papermaking wire.

As long as the above requirements are satisfied, the hydrophilic fine fibers are not particularly limited. For example, cellulose fibers such as pulp, cotton and rayon; hydrophilic synthetic fibers such as polyacrylonitrile and polyvinyl alcohol; inorganic fibers such as kaolin, bentonite and hydrotalcite can be used. These hydrophilic fine fibers can be used alone or in combination of two or more.

As the hydrophilic fine fibers, commercially available hydrophilic fibers can be used. For example, pulp flocks (trade name) manufactured by Sanyo Kokusaku Pulp Co., Ltd., obtained by beating wood pulp such as softwood pulp and hardwood pulp, and then mechanically pulverizing and separating the resulting pulp with a sieve of 0.5 mm or less. Can be As another example, cellulose fibers such as wood pulp are mechanically pulverized, then hydrolyzed with an acid, and further mechanically pulverized cellulose fine fibers [KC Floc (manufactured by Sanyo Kokusaku Pulp Co., Ltd.) Trade name) and Avicel (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd.]. In addition, as commercially available inorganic fine fibers, hydrated magnesium silicate fibers [Eight Plus M manufactured by Mizusawa Chemical Industries, Ltd.]
L-30 (trade name)]. Among these commercially available products, cellulose fine fibers obtained by pulverizing and pulverizing pulp can be obtained at lower cost and can be preferably used.

Next, the hot-melt adhesive fiber used arbitrarily in the fiber web 108 will be described.
As the heat-fusible adhesive fibers, fibers that are melted by heating and adhere to each other can be used. Specifically, for example, polyethylene, polypropylene, polyolefin-based fibers such as polyvinyl alcohol, polyester-based fibers, polyethylene-polypropylene Examples include conjugate fibers, polyethylene-polyester conjugate fibers, low-melting-point polyester-polyester conjugate fibers, polyvinyl alcohol-polypropylene conjugate fibers having a hydrophilic fiber surface, and polyvinyl alcohol-polyester conjugate fibers. When using a conjugate fiber, any of a core-sheath type conjugate fiber and a side-by-side type conjugate fiber can be used. These heat fusible adhesive fibers can be used alone or in combination of two or more. Examples of the heat-fusible adhesive fiber preferably used in the present invention include polyvinyl alcohol and polyester.

The heat-meltable adhesive fiber generally has a fiber length of 2 to 60 mm and a fiber diameter of 0.5 to 3 denier.

Next, the superabsorbent polymer 106 contained in the first absorbent sheet 100 of the present invention will be described. As shown in FIG. 1, the superabsorbent polymer 10
Numeral 6 is included in the first absorbent sheet 100 of the present invention, and is dispersed in the space formed between the fibers constituting the first absorbent sheet 100 of the present invention. More specifically, as shown in FIG.
Is mainly contained inside the fiber web 108, and is preferably dispersed in the space formed between the fibers constituting the fiber web 108. As a result, the superabsorbent polymer 106 is securely fixed in the first absorbent sheet 100 of the present invention, and the occurrence of gel blocking is suppressed. In addition, here, "the superabsorbent polymer 10
"6 is contained in the first absorbent sheet 100" does not mean that the superabsorbent polymer 106 does not exist on the surface of the first absorbent sheet 108 of the present invention at all, and will be described later. In the preferred method for producing the first absorbent sheet according to the present invention, a small amount of the superabsorbent polymer inevitably present on the surface of the absorbent sheet is acceptable, and most of the superabsorbent polymer 106 is the present invention In the first absorbent sheet 100.

The superabsorbent polymer 106 is adhered to the fibers constituting the first absorbent sheet 100 of the present invention, preferably the fibers constituting the fibrous web 108. Thereby, the fixation of the superabsorbent polymer 106 is further strengthened, and the gel blocking is further suppressed. Here, the superabsorbent polymer 106 does not need to have all the particles adhered to the fiber. Preferably, 50% by weight or more of the superabsorbent polymer 106 is adhered to the fiber based on the total amount thereof.
Preferably, at least 70% by weight is adhered to the fibers.
If the amount of adhesion of the superabsorbent polymer 106 is less than 50% by weight, the effect of immobilization may not be sufficiently exhibited, which is not preferable. The method for bonding the superabsorbent polymer 106 to the fibers will be described later.

When a highly agglomerated polymer of the particle agglomerated type in which a spherical polymer is used as primary particles and agglomerated into secondary particles is used as the superabsorbent polymer 106, all of the primary particles are used. The superabsorbent polymer does not need to adhere to the fiber, and if a part of the secondary particles adhere to the fiber, the superabsorbent polymer is fixed to the fiber.

Preferably, the superabsorbent polymer 106
Are not dispersed in a layered manner in the first absorbent sheet 100 of the present invention, but are dispersed three-dimensionally as shown in FIG. Therefore, the superabsorbent polymer can be dispersed in a large amount. That is, while the upper limit of the spraying basis weight of the superabsorbent polymer in the conventional absorbent sheet in which the superabsorbent polymer is dispersed in a layered (that is, two-dimensional) is generally about 50 to 100 g / m ² , First of the present invention
In the absorbent sheet 100, the superabsorbent polymer 1
06 can be dispersed three-dimensionally, so that the upper limit of the spray basis weight of the superabsorbent polymer 106 is about 200 to 3
00 g / m ^2, and the spray basis weight of the superabsorbent polymer 106 can be increased to about three times that of the conventional absorbent sheet. Therefore, the first absorbent sheet 100 of the present invention dramatically increases the amount of liquid absorbed as compared with the conventional absorbent sheet. Further, the superabsorbent polymer 10
6 are three-dimensionally dispersed and used in combination with the transmission layer and the diffusion layer, whereby the original absorption performance of the superabsorbent polymer 106 is more effectively exhibited. That is, even when the same amount of the high-absorbent polymer as the conventional absorbent sheet is used, the absorption performance can be further improved, and as a result, the absorbent sheet can be made extremely thinner than the conventional product. In addition, since the weight per unit area can be increased, it can be suitably used as an absorbent body such as a disposable diaper which requires a large absorption capacity.

The superabsorbent polymer 106 preferably has a spray basis weight of 1 to 300 g / m ² ,
More preferably, it is 300 g / m ² ,
0 g / m ² , more preferably 20 to 150 g.
/ M ² is particularly preferred. Spray basis weight is 1g
If it is less than / m ² , the water absorption capacity is insufficient, and sufficient functions cannot be exhibited. On the other hand, when the spray basis weight is more than 300 g / m ² , the fiber web 108 and the fiber aggregate 105
It is preferable that the adhesive strength be within the above range, since the adhesive force with the polymer will decrease and the superabsorbent polymer 106 will easily fall off.

As the high-absorbency polymer 106, a polymer capable of absorbing and retaining a liquid 20 times or more its own weight and gelling is preferable. Examples of such superabsorbent polymers include starch, crosslinked carboxymethylated cellulose, polymers or copolymers of acrylic acid or alkali metal acrylates, such as polyacrylic acid and its salts, and polyacrylate graft polymers. Coalescence can be mentioned. As the polyacrylate, a sodium salt can be preferably used. Further, a comonomer such as maleic acid, itaconic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2-hydroxyethyl (meth) acrylate or styrenesulfonic acid is used for acrylic acid. Copolymers copolymerized within a range that does not reduce the performance of the superabsorbent polymer can also be preferably used.

Next, the fiber aggregate 105 having the absorbent surface 102 in the first absorbent sheet 100 of the present invention will be described. Here, the “absorbing surface” refers to a surface that first absorbs liquid mainly when the first absorbent sheet 100 of the present invention absorbs liquid. That is, when the first absorbent sheet 100 of the present invention is used, the liquid is mainly absorbed from the fiber aggregate 105 side.

The fiber aggregate 105 is formed on the absorbent surface 1
The superabsorbent polymer 106 is not included on the 02 side. Here, “does not contain a superabsorbent polymer” does not mean that the fiber aggregate 105 does not contain the superabsorbent polymer 106 on the absorbent surface 102 side at all, and the present invention described below will not be described. The trace amount of the superabsorbent polymer which is inevitably mixed in the preferred method of manufacturing the first absorbent sheet 100 means that it is substantially free of the superabsorbent polymer although it is acceptable.

The fiber aggregate 105 has an average fiber length of 1 to 1.
A bulky cellulose fiber having a fiber roughness of at least 0.3 mg / m at 20 mm is mainly used, and is obtained by mechanical entanglement, physical entanglement, heat bonding, and the like of the fiber,
For example, paper or nonwoven fabric can be used. As the paper, paper obtained by wet papermaking or creped paper can be used.

The fiber aggregate 105 has an average fiber length of 1-2.
As described above, a bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more at 0 mm is mainly used, and such a bulky cellulose fiber is preferably 30% based on 100 parts by weight of the fiber assembly. It is contained in an amount of 50 parts by weight or more, more preferably 50 to 98 parts by weight. In addition, as for the details of such bulky cellulose fibers, the detailed description of the bulky cellulose fibers constituting the fiber web 108 is appropriately applied.

Further, the fiber aggregate 105 may contain heat-meltable adhesive fibers. Such a heat-meltable adhesive fiber is preferably contained in an amount of 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, based on 100 parts by weight of the fiber assembly. In addition, as for the details of the heat-fusible adhesive fibers, the detailed description of the heat-fusible adhesive fibers constituting the fiber web 108 is appropriately applied.

Other components that can be added to the fiber assembly 105 include a strong auxiliary. As such a strong auxiliary, the strong auxiliary described in detail in the description of the first absorbent sheet can be used. The strong adjuvant is preferably contained in an amount of 0 to 30 parts by weight based on 100 parts by weight of the fiber aggregate, and more preferably 0 to 30 parts by weight.
-20 parts by weight.

For the same reason as in the case of the fibrous web 108, the fibrous aggregate 105 has a tensile strength when wet measured by JIS-P-8113 of 50 g or more as measured by drying alone and forming a sheet. And more preferably 100 g or more.

The fiber aggregate 105 has a basis weight of 10
２００200 g / m ² , preferably 10-50 g
/ M ² is more preferable. The basis weight is 10 g /
If it is less than m ^2, when the superabsorbent polymer 106 swells, the superabsorbent polymer 106 becomes
And may fall out. On the other hand, when the basis weight exceeds 200 g / m ² , the density of the fiber aggregate 105 is too high, and the first absorbent sheet 100 of the present invention may be too hard. .

The fiber aggregate 105 may be manufactured before the fiber web 108 is manufactured, or when the first absorbent sheet 100 of the present invention is manufactured.
The fiber web 108 may be manufactured at the same time.

As described above, the first absorbent sheet 1 of the present invention
00 is the fiber aggregate 105, the fiber web 108
And the above-described superabsorbent polymer 106 is mainly formed.
The first and second absorbent sheets 100
Is a preferable range of the basis weight of the fiber assembly 105.
Is 10 to 200 g / m^TwoWherein the superabsorbent polymer is
Spread basis weight of 106 is 1 to 300 g / m^TwoAnd the above fiber
The basis weight of the web 108 is 10 to 200 g / m^TwoIt is.
More preferably, the basis weight of the fiber aggregate 105 is 1
0-100g / m^TwoAnd the superabsorbent polymer 10
Spray basis weight of 6 to 5 to 200 g / m^TwoAnd the above fiber
The basis weight of Eb 108 is 10 to 100 g / m. ^TwoIt is.

[0081] Also, the first basis weight of the total of the absorbent sheet 100 of the present invention is preferably 21~500g / m ^2, more preferably from 30~300g / m ^2, 50~200g / m ² is more preferable.

Further, the first absorbent sheet 100 of the present invention
Has a thickness of 0.3 to 5 mm under a load of 2.5 g / cm ^2.
Is preferably, and more preferably, 0.5 to 3 mm. Moreover, when making an ultra-thin absorbent sheet, the thickness under a load of 2.5 g / cm ² is 0.3 to 1.5.
mm, more preferably 0.3 to 1.2 mm.

The first absorbent sheet 100 of the present invention having the above-described structure has a liquid diffusion gradient in its single structure. More specifically, since the liquid permeability is high on the absorption surface 102 side of the first absorbent sheet 100, little liquid remains on the absorption surface 102. Then, the absorbed liquid is quickly transmitted to the superabsorbent polymer 106, and particularly the fiber web 108 having high diffusivity.
Is diffused over the entire surface of the first absorbent sheet 100 on the second surface side. Thus, the first absorbent sheet 1
00 has a liquid permeation / diffusion / fixation function in its single structure, so that the liquid can be fixed with the superabsorbent polymer 106 more quickly and reliably. Further, when the first absorbent sheet 100 absorbs a large amount of liquid, the liquid is quickly transmitted to the superabsorbent polymer 106 and absorbed therein. Even if the liquid cannot be completely retained by the superabsorbent polymer 106, the liquid is diffused on the second surface side of the fiber web 108 and does not leak out. in this way,
The first absorbent sheet 100 of the present invention is particularly effective when absorbing a large amount of liquid at a time and when using a high-absorbent polymer having a low absorption rate.

Next, the second absorbent sheet of the present invention will be described. As shown in FIG. 2, the second absorbent sheet 200 of the present invention is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers. , Fiber aggregate 205
And a fiber web 208. The fiber aggregate 205 has an absorbent surface 202 and does not include a superabsorbent polymer on the absorbent surface 202 side. The fiber aggregate 205 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3.
mg / m or more of bulky cellulose fibers 12 and hydrophilic fine fibers 14 having an average fiber length of 0.02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one surface side is the other. Is higher than the existence ratio on the surface side.

On the other hand, as shown in FIG. 2, the fiber web 208 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m.
It is mainly composed of bulky cellulose fibers 12 of g / m or more. Then, the fiber web 208 is connected to the fiber assembly 2 described above.
05 is adjacent to the fiber aggregate 205 on the side where the proportion of the hydrophilic fine fibers is high. For the sake of simplicity, in the same manner as described for the fibrous web 108 in the first absorbent sheet 100, the proportion of the hydrophilic fine fibers in the surface of the fiber aggregate 205 of the second absorbent sheet 200 The surface side with a low value is referred to as a first surface, and the surface side with a high proportion of the hydrophilic fine fibers is referred to as a second surface.

As shown in FIG. 2, the fiber aggregate 205 and the fiber web 208 are integrated. Further, the superabsorbent polymer 206 is contained inside the absorbent sheet 200, and
It is adhered to the fibers constituting 00.

As described above, the second absorbent sheet 2 of the present invention
One of the features is that, like the first absorbent sheet 100, it has an integrated structure including a fiber aggregate 205 and a fiber web 208 and a superabsorbent polymer 206 contained therein. It is. Such an integral structure of the second absorbent sheet of the present invention is the same as that of the first absorbent sheet and is not specifically described here. However, the detailed explanation regarding the integral structure of the first absorbent sheet will be omitted. 2 Applicable to an absorbent sheet as appropriate.

Next, the fiber web 208 in the second absorbent sheet 200 of the present invention will be described. As described above, the fiber web 208 has an average fiber length of 1 to 20 m.
m, which is mainly composed of bulky cellulose fibers having a fiber roughness of 0.3 mg / m or more, and the surface side of the fiber aggregate 205 where the proportion of the hydrophilic fine fibers is high, that is, the second side. It is adjacent to the fiber assembly 205 on the surface side. By using such bulky cellulose fibers as the fibers constituting the fiber web 208, not only the dispersibility and the degree of immobilization of the superabsorbent polymer 206 are further improved, but also the fiber web is particularly improved during wet papermaking. 208 can be more easily controlled for drainage. Furthermore, since the bulky cellulose fiber can form a bulky and high porosity fiber web, the superabsorbent polymer 206 is easily embedded, dispersed, and fixed three-dimensionally in the fiber web 208, and The occurrence of gel blocking of the superabsorbent polymer 206 can also be suppressed.

The bulky cellulose fiber is preferably contained in an amount of 30 parts by weight or more, more preferably 50 to 99 parts by weight, based on 100 parts by weight of the fiber web.

The details of the bulky cellulose fibers used in the first absorbent sheet 100 are appropriately applied to the details of the bulky cellulose fibers constituting the fiber web 208.

It is also preferable to add a strong adjuvant to the fiber web 208 described in detail in the description of the first absorbent sheet. These strong adjuvants are used in an amount of 0 to 30 based on 100 parts by weight of the fibers constituting the fiber web 208.
Parts by weight, preferably 0 to 20 parts by weight.

The fiber web 208 may be blended with ordinary cellulose fibers capable of forming hydrogen bonds, such as wood pulp and non-wood pulp, in order to increase the strength.

In this case, based on 100 parts by weight of the fiber web, 30 to 99 parts by weight of the bulky cellulose fiber, 1 to 70 parts by weight of the wood pulp or non-wood pulp, and 0 to strong supplements
Preferably, it comprises 30 parts by weight. More preferably, based on 100 parts by weight of the fiber web, 50 to 95 parts by weight of the bulky cellulose fiber, 5 to 50 parts by weight of the wood pulp or non-wood pulp, and 0 to 20 parts by weight of the strong adjuvant. Part.

Further, it is preferable to add a heat-meltable adhesive fiber to the fiber web 208. By adding such hot-melt adhesive fibers, the structure of the absorbent sheet of the present invention can be kept stable even when wet. In addition, as for the details of the heat-fusible adhesive fibers, the detailed description of the heat-fusible adhesive fibers used in the first absorbent sheet 100 is appropriately applied.

In this case, the fiber web 208 contains 30 to 99 parts by weight of the bulky cellulose fiber and 1 to 50 parts by weight of the hot-melt adhesive fiber based on 100 parts by weight of the fiber web. Is preferred. More preferably, the composition comprises 50 to 97 parts by weight of the bulky cellulose fiber and 3 to 30 parts by weight of the hot-melt adhesive fiber based on 100 parts by weight of the fiber web.

The points that were not described in detail with respect to the fiber web 208 are the same as those of the first absorbent sheet 1.
The detailed description of the fiber web 108 at 00 is applied as appropriate.

Next, the superabsorbent polymer 206 contained in the second absorbent sheet 200 of the present invention will be described. As shown in FIG.
6, like the superabsorbent polymer 106 contained in the first absorbent sheet 100, is contained inside the second absorbent sheet 200 of the present invention. It is dispersed in the space formed between the constituent fibers. More specifically, as shown in FIG. 2, the superabsorbent polymer 206 is mainly contained inside the fiber web 208 and is dispersed in the space formed between the fibers constituting the fiber web 208. Is preferred. As a result, the superabsorbent polymer 206 is securely fixed in the second absorbent sheet 200 of the present invention, and the occurrence of gel blocking is suppressed.

The superabsorbent polymer 206 is adhered to the fibers constituting the second absorbent sheet 200 of the present invention, preferably the fibers constituting the fiber web 208. Therefore, the fixation of the superabsorbent polymer 206 becomes stronger, and the gel blocking can be further suppressed.

The points of the superabsorbent polymer 206 that have not been described in detail, such as the dispersion state, type, and various physical properties of the superabsorbent polymer 206, are described in detail in the first absorbent sheet 100. Absorbent polymer 10
The description described in detail with regard to No. 6 is appropriately applied.

Next, the fiber aggregate 205 having the absorbent surface 202 in the second absorbent sheet 200 of the present invention will be described. The fiber aggregate 205 does not include the superabsorbent polymer 206 on the absorption surface 202 side. Here, the meaning of the “absorbing surface” is the same as the meaning in the first absorbent sheet 100. The fiber aggregate 205 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.1 mm.
It contains bulky cellulose fibers of 3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the presence ratio of the hydrophilic fine fibers on one side is the other side. Higher than the presence ratio on the side. The first surface of the fiber aggregate 205 is
It corresponds to 2. On the other hand, the second surface of the fiber aggregate 205 is adjacent to the fiber web 208 as shown in FIG.

As described above, the fiber aggregate 205 has a gradient in the thickness direction with respect to the existing ratio of the hydrophilic fine fibers, and the structure of the fiber aggregate 205 having such a gradient is as follows. The first absorbent sheet 100
Is the same as the structure of the fiber web 108. Therefore,
For details of the structure and the like of the fiber aggregate 205, the description in detail for the fiber web 108 of the first absorbent sheet 100 is appropriately applied. In addition, the fiber assembly 2
The details of the bulky cellulose fibers and the hydrophilic fine fibers constituting the first absorbent sheet 1
The detailed description of the bulky cellulose fiber and the hydrophilic fine fiber in the fibrous web 108 of No. 00 is appropriately applied.

As described above, the second absorbent sheet 2 of the present invention
00 is the fiber aggregate 205, the fiber web 208
And the superabsorbent polymer 206 as a main component. The preferred range of the basis weight of the fiber aggregate 205, the fiber web 208, and the superabsorbent polymer 206 is the same as the preferred range of the first absorbent sheet 100.
The description detailed in 00 is appropriately applied. The details such as the basis weight and the thickness of the second absorbent sheet 200 are the same as those of the first absorbent sheet 100, and the detailed description of the first absorbent sheet 100 is appropriately applied.

In the second absorbent sheet 200 of the present invention thus configured, the first absorbent sheet 100
Similarly, the liquid has a liquid diffusion gradient. More specifically, the second absorbent sheet 200 has a liquid diffusion gradient from the absorbent surface 202 of the second absorbent sheet 200 toward the interior thereof (particularly, the portion of the fiber aggregate 205). That is, since the bulky cellulose fibers are mainly formed from the absorption surface 202 (first surface) to the vicinity thereof, a bulky network structure is formed. As a result, liquid permeability is high from the absorption surface 202 (first surface) to the vicinity thereof, and the liquid quickly permeates into the fiber aggregate 205. Since the second surface side of the fiber assembly is formed mainly of the hydrophilic fine fibers having a high surface area, the absorption surface 202 is formed.
The liquid transmitted from the (first surface) side can be quickly diffused over the entire surface of the second absorbent sheet. As a result, the liquid is efficiently fixed by the superabsorbent polymer 206. Thus, the second absorbent sheet 2
00 also has a liquid permeation / diffusion / fixation function in its single structure, similar to the first absorbent sheet 100, so that liquid can be more quickly and reliably absorbed by the superabsorbent polymer 206. Can be fixed.

The first absorbent sheet and the second absorbent sheet of the present invention
In the absorbent sheet, other layers may be further integrated as necessary.

Next, the first absorbent sheet of the present invention and the second absorbent sheet
A preferred method for producing the absorbent sheet will be described.

First, a preferred method for producing the first absorbent sheet of the present invention will be described. The first absorbent sheet has an average fiber length of 1 to 20 mm and a fiber roughness of 0.1 mm.
It contains bulky cellulose fibers of 3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one surface side is the other. In the wet fibrous web, which is higher than the existing ratio on the surface side, the superabsorbent polymer is sprayed on the surface where the existing ratio of the hydrophilic fine fibers is low, and the average fiber length is 1 to 20 mm, and the fiber roughness is further increased. It is characterized by including a step of laminating a fiber aggregate mainly composed of bulky cellulose fibers of 0.3 mg / m or more, drying these, and integrating them.

These steps will be described below.

First, bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm are contained. A fiber web is formed in which the proportion of the hydrophilic fine fibers present on the surface side is higher than the proportion present on the other surface side. The method for forming the fiber web is not particularly limited, and for example, a dry papermaking method or the like can be used, but preferably, a wet papermaking method is used. This is because, as described later, when the superabsorbent polymer is sprayed on the fiber web, the fiber web must be in a state of being wet and having a very high degree of freedom of the fiber,
This is because, if the fiber web is formed by a wet papermaking method, the fiber web is immediately realized in a wet state, so that it is not necessary to perform the wet step in a separate step. Further, since the fibers of the fiber web obtained by the wet papermaking method are not sufficiently bonded to each other before drying, when the superabsorbent polymer is sprayed in this state, the superabsorbent polymer is interwoven between the fibers. There is also an advantage that it can be easily buried three-dimensionally in the space formed in the space, and a large amount of superabsorbent polymer can be sprayed. Further, by using the wet papermaking method, the difference in the average fiber length between the bulky cellulose fibers and the hydrophilic fine fibers is used, and the presence of the hydrophilic fine fibers with respect to the thickness direction of the fiber web. It is easier to provide a gradient in the ratio.

The method of forming the fiber web by the wet papermaking method will be described in detail. First, the bulky cellulose fibers and the hydrophilic fine fibers are dispersed in water to form a slurry. The slurry is supplied to the forming part 130 as shown in FIG. When the slurry is sprayed on the round net 132, water in the slurry is removed through the round net 132, and at the same time, the wet fiber web 108 is formed on the round net 132. As shown in FIG. 5, in the fiber web 108, the bulky cellulose fibers 12 form a bulky network structure in the thickness direction. On the other hand, since the hydrophilic fine fibers 14 in the slurry are finer than the bulky cellulose fibers, they pass through the network structure together with water and accumulate on the round net 132. As a result, the distribution of the hydrophilic fine fibers has a gradient in the thickness direction of the fiber web 108. That is, as shown in FIG. 5, among the surfaces of the fiber web 108, the round net 1
The existing ratio of the hydrophilic fine fibers on the surface in contact with 32 is higher than the existing ratio on the other surface.

As described above, in the preferred method for producing the fibrous web 108 using the wet papermaking method, the difference in fiber length and fiber diameter between the bulky cellulose fiber and the hydrophilic fine fiber is utilized. The fiber web 108
A gradient is provided in the proportion of the hydrophilic fine fibers present in the thickness direction.

The concentration of the bulky cellulose fibers in the slurry is preferably from 0.02 to 1% by weight based on the total amount of the slurry, and more preferably,
0.03 to 0.7% by weight. If the concentration of the bulky cellulose fiber is less than 0.02% by weight, the desired permeation rate becomes insufficient, or the amount of waste water for obtaining the desired basis weight becomes too large, resulting in energy consumption. If the concentration of the bulky cellulose fiber exceeds 1% by weight, the dispersibility of the fiber is deteriorated and the paper layer becomes uneven, so that the above range is preferable.

On the other hand, the concentration of the hydrophilic fine fibers in the slurry is preferably 0.002 to 0.5% by weight, more preferably 0.003 to 0.5% by weight based on the total amount of the slurry. 3% by weight. If the concentration of the hydrophilic fine fibers is less than 0.002% by weight, the desired diffusibility may not be obtained, and the concentration of the hydrophilic fine fibers exceeds 0.5% by weight. And the first
Since the hydrophilic fine fibers are also present on the surface side and a desired diffusion gradient may not be obtained, the above range is preferable.

The concentration of the hot-melt adhesive fiber optionally used for the fiber web 108 in the slurry is preferably 0.001 to 0.3% by weight, and 0.002 to 0.3% by weight. More preferably, it is set to 0.2% by weight. If the above concentration is less than 0.001% by weight,
In some cases, the purpose of keeping the structure of the fiber web 108 stable may not be achieved. When the concentration exceeds 0.3% by weight, the hydrophilicity of the entire fiber web 108 may be reduced. Is preferred.

As described above, in the preferred method of producing the fiber web 108 using the wet papermaking method shown in FIG. 3, when the slurry is sprayed on the round mesh 132, the bulkiness of the bulky cellulose fibers is reduced. A network structure is formed, and the hydrophilic fine fibers pass through the space in such a bulky network structure and the round net 1
32. For this purpose, it is important to make the average fiber length of the hydrophilic fine fibers larger than the mesh of the round net 132. If the average fiber length of the hydrophilic fine fibers is smaller than the mesh of the round net 132, since the hydrophilic fine fibers pass through the round net 132, in the thickness direction of the fiber web 108, It is not preferable because a gradient cannot be effectively provided in the proportion of the hydrophilic fine fibers. On the other hand, if the mesh of the round mesh 132 is too small, the hydrophilic fine fibers on the round mesh 132 are undesirably clogged. Therefore, the round net 1
The aperture diameter of 32 (papermaking wire) wires is 22-
It is preferably 300 μm (580 to 50 mesh), more preferably 45 to 250 μm (330 to 60 mesh) [based on New JIS (1987)].

According to the preferred method for producing the fibrous web 108 using the wet papermaking method described above, it is particularly easy to provide a gradient in the distribution of the hydrophilic fine fibers in the thickness direction of the fibrous web 108. Can be. The degree of the gradient depends on the speed (water drainage speed) at which the fiber web 108 formed on the round net 132 is dewatered. That is, although it depends on the papermaking speed and the basis weight of the fiber web,
If the speed of the dehydration is low, the degree of the gradient becomes small,
As a result, the hydrophilic fine fibers may be almost uniformly distributed in the thickness direction of the fiber web 108. On the other hand, it is preferable that the dehydration speed is high because the degree of the gradient becomes large, but large energy is required to increase the dehydration speed. In consideration of these, in the present invention, the dehydration speed is preferably 2 liter / m ² · sec or more, and more preferably 3 to 30 liter / m ² · sec. For dehydration, for example, as shown in FIG. 3, a suction box 136 used in a usual wet paper machine can be used.

According to the above-described method, it is possible to produce a fiber web capable of exhibiting liquid absorption and permeation and liquid diffusion in a single papermaking process, thereby simplifying the papermaking process. .

The wet fibrous web 108 thus formed is connected to the papermaking wire 13 as shown in FIG.
4 and the front and back are reversed. Next, the fiber web 108 is picked up by the conveyor 140 and its front and back are turned over again, and the superabsorbent polymer 106 is sprayed thereon while its wet state is maintained. The surface on which the superabsorbent polymer 106 is scattered is the surface side of the fiber web 108 where the proportion of the hydrophilic fine fibers is low, that is, the first surface side. In addition, when using the previously manufactured dry fiber web 108,
Before spraying the superabsorbent polymer 106 on the fiber web 108, water is sprayed on the fiber web 108 to keep it wet. The wet state of the fiber web is preferably such that water is contained in an amount of 20 to 500 parts by weight, more preferably 50 to 30 parts by weight, based on 100 parts by weight of the dry fiber web.
Contains 0 parts by weight of water. If the amount of water is less than 20 parts by weight, the sprayed superabsorbent polymer 106 absorbs water and wets, and the adhesiveness cannot be obtained. When the amount of water exceeds 500 parts by weight, the superabsorbent polymer 106
Is excessively absorbed and may cause poor drying in a drying step described later.

As shown in FIG. 3, the above-described superabsorbent polymer 1 was applied to the wet fiber web 108 as shown in FIG.
Spray 06. As a result, the sprayed superabsorbent polymer 106 is buried in the fibers constituting the fiber web 108, absorbs water, becomes tacky, and is adhered and fixed to the fibers. Further, the fiber web 108 in a wet state has a degree of freedom since the fibers constituting the fiber web 108 are not yet bonded to each other, so that the superabsorbent polymer 106 can be three-dimensionally dispersed. . Therefore, a larger amount of the highly absorbent polymer can be stably fixed as compared with the conventional absorbent sheet. When spraying the superabsorbent polymer 106, the superabsorbent polymer 106 may be evenly spread over the entire surface of the wet fiber web 108, or as necessary, in the longitudinal direction of the wet fiber web 108. It is also possible to disperse the fibers in a streak shape at intervals, or to intermittently disperse them in a shot shape in the longitudinal direction of the wet fiber web 108.

Next, as shown in FIG. 3, the fiber aggregate 105 is overlaid on the surface of the fiber web 108 on which the superabsorbent polymer 106 has been sprayed. In this case, as the fiber aggregate 105, as shown in FIG. 3, a previously manufactured one can be unwound and used, or a fiber manufactured in parallel with the manufacture of the fiber web 108 can be used. Can also be used. At the time when the fiber web 108 and the fiber aggregate 105 are overlapped, the fibers in the fiber web 108 still have a degree of freedom. And the fibers in the fiber web 108 and the fibers in the fiber aggregate 105 are tightly and easily entangled.

Subsequently, the superimposed body of the fiber web 108 and the fiber assembly 105 is pressed into a press part 138.
After drying with a dryer 142, the fibers constituting the fiber web 108 and the fibers constituting the fiber aggregate 105 are more closely entangled with each other, and furthermore, the effects of hydrogen bonding and heat fusion are also reduced. In addition, the fiber web 108 and the fiber aggregate 105 are integrated to obtain the first absorbent sheet 100 of the present invention. The drying temperature depends on the type of the fiber used, but is 100 to 1
The drying temperature is preferably in the range of 80 ° C, and more preferably the drying temperature is in the range of 105 to 150 ° C. By drying and unifying, the fiber web 108 and the fiber aggregate 10
5 are integrated, and the fibers constituting the fiber web 108 are combined with each other to form a sheet. In addition,
The drying means is not particularly limited, and for example, a Yankee dryer, an air-through dryer, or the like can be used.

Particularly preferably, the first absorbent sheet 100 of the present invention is produced by a single in-line process using a wet paper machine. That is, as shown in FIG. 3, the fiber web 108 is formed in the forming part 130 of the wet paper machine.
Is formed, and in the suction dewatering step 136, the fiber web 1 is formed.
08 is dehydrated, the superabsorbent polymer 106 is sprayed on the first surface side of the fiber web 108 immediately before the press part 138, and the fiber aggregate 105 is superimposed thereon. Web 108
And the fiber assembly 105 are pressed, and then dried and integrated with a dryer 142. According to such a method, the first absorbent sheet 100 of the present invention can be manufactured at high speed and easily.

As the wet paper machine, an ordinary paper machine can be used. Examples of such a paper machine include a fourdrinier paper machine, a former paper machine and a round mesh paper machine. In addition, about the process other than the above, the process in a normal papermaking method can be used suitably.

Next, a preferred method for producing the second absorbent sheet of the present invention will be described. The second absorbent sheet has an average fiber length of 1 to 20 mm and a fiber roughness of 0.1 mm.
A superabsorbent polymer is sprayed on a wet fiber web mainly composed of bulky cellulose fibers of 3 mg / m or more, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg are spread thereon.
/ M or more bulky cellulose fiber and average fiber length
A fiber aggregate containing hydrophilic fine fibers having a size of 02 to 0.5 mm and having a higher proportion of the hydrophilic fine fibers on one surface side than the presence ratio on the other surface side, Characterized in that it includes a step of superimposing the surface side of the fiber web having a high proportion of fine fibers and the fiber web so as to be adjacent to each other, and drying and integrating them.

These steps will be described below.

First, a fiber web mainly composed of bulky cellulose fibers is formed. The method for forming the fiber web is not particularly limited, but it is preferable to use a wet papermaking method for the same reason as the preferable method for producing the first absorbent sheet.

The method for producing the fiber web will be described in more detail. The bulky cellulose fiber and, if necessary, the hot-melt adhesive fiber and the strong adjuvant are dispersed in water to a predetermined concentration. Mix with slurry. The slurry is supplied to a round net of the forming part 230 as shown in FIG. As a result, the fiber web 208 is formed on the papermaking wire 234.

The fiber web 208 formed on the papermaking wire 234 is dehydrated by the suction box 236. Then, while maintaining the wet state,
The superabsorbent polymer 206 is spread on the fiber web 208. When using a previously manufactured dry fiber web, before spraying the superabsorbent polymer 206 on the fiber web 208, water is sprayed on the fiber web 208 to make it wet. deep. Regarding the wet state of the fiber web, the detailed description of the preferred method of manufacturing the first absorbent sheet is appropriately applied.

As shown in FIG. 4, the superabsorbent polymer 2 was added to the wet fiber web 208 as shown in FIG.
Spray 06. The spraying method is the same as in the case of manufacturing the first absorbent sheet.

Next, as shown in FIG. 4, on the surface of the fibrous web 208 on which the superabsorbent polymer 206 has been sprayed, the bulky cellulose fibers and the hydrophilic fine fibers are contained. The fiber aggregate 205 in which the proportion of the hydrophilic fine fibers present on the surface side is higher than the proportion present on the other side is superimposed on the fiber web 208. In the superposition, the surface side (that is, the second surface side) of the surface of the fiber assembly 205 where the proportion of the hydrophilic fine fibers is high (that is, the second surface) is the fiber web 208.
Is performed adjacent to. In this case, the fiber aggregate 205
As shown in FIG. 4, a wet papermaking method using the difference in average fiber length between the bulky cellulose fibers and the hydrophilic fine fibers (the above-described first absorbent sheet 100)
The same as the preferred method of manufacturing the fiber web 108 in the above)
Can be used by unwinding a fiber assembly produced in advance, or a fiber assembly produced using the wet papermaking method in parallel with the production of the fiber web 208 can be used. The details of the method for producing the fiber aggregate 205 using a wet papermaking method utilizing the difference in average fiber length between the bulky cellulose fibers and the hydrophilic fine fibers are described in detail in the description of the first absorbent fiber. The detailed description of the preferred method of manufacturing the fiber web 108 in the sheet 100 is appropriately applied.

Subsequently, a superimposed body of the fiber web 208 and the fiber aggregate 205 is pressed by a press part 238.
After drying with a dryer 242, the fibers constituting the fiber web 208 and the fibers constituting the fiber aggregate 205 are more closely entangled with each other, and furthermore, the effects of hydrogen bonding and heat fusion are also reduced. In addition, the fiber web 208 and the fiber aggregate 205 are integrated, and the second absorbent sheet 200 of the present invention is obtained.

[0131] Particularly preferably, the second absorbent sheet 200 of the present invention is produced by an in-line single process using a wet paper machine, like the first absorbent sheet. That is, as shown in FIG. 4, the fiber web 208 is formed in the forming part 230 of the wet paper machine, the fiber web 208 is dehydrated in the suction dewatering step 236, and the fiber web 208 is formed on the fiber web 208 immediately before the press part 238. While the superabsorbent polymer 206 is sprayed, the fiber aggregate 205 is coated thereon with the fiber web 208 and the fiber aggregate 20.
5, the fiber web 208 and the fiber assembly 205 are pressed by the press part 238, and then guided to a dryer 242 by a conveyor 240, and the fiber web 208 and the fiber aggregate 205 are pressed by the dryer 242. And dried. According to such a method, the second absorbent sheet 200 of the present invention can be manufactured at high speed and easily.

[0132] Regarding the points that are not described in detail in the description of the preferred method for producing the second absorbent sheet, the description in detail in the preferred method for producing the first absorbent sheet are appropriately applied. In addition, for the points not particularly described in the description of the preferable manufacturing method of the first absorbent sheet and the second absorbent sheet, a conventionally known paper making method can be appropriately used.

As described above, the first absorbent sheet and the second absorbent sheet of the present invention
Although the method for producing the absorbent sheet has been described based on the preferred embodiment, it goes without saying that the method for producing the first and second absorbent sheets of the present invention is not limited to such a method.

Next, the first absorbent sheet of the present invention and the second absorbent sheet
An absorbent article using the absorbent sheet will be described.

The absorbent article using the first absorbent sheet of the present invention (hereinafter referred to as the first absorbent article) has a liquid-absorbable surface layer, a liquid-retentive absorbent layer, and a liquid-impermeable leakproof. In the absorbent article having a layer, the first layer is provided on the absorbent layer side of the surface layer, the absorbent layer, or the leakproof layer.
It is characterized by including an absorbent sheet.

The absorbent article using the second absorbent sheet of the present invention (hereinafter, referred to as a second absorbent article) has a liquid-absorbable surface layer, a liquid-retentive absorbent layer, and a liquid-impermeable absorbent layer. In the absorbent article having a leakproof layer, the second absorbent sheet is included on the surface layer, the absorbent layer, or the absorbent layer side of the leakproof layer.

Hereinafter, preferred embodiments of the first and second absorbent articles will be described with reference to the drawings.

First, a preferred embodiment of the first absorbent article of the present invention will be described with reference to FIGS. Here, FIG. 6 is a schematic diagram showing a cross section in the width direction of a sanitary napkin as a first preferred embodiment of the first absorbent article of the present invention. FIGS. 7 to 11 are schematic views showing cross sections in the width direction of a sanitary napkin as another preferred embodiment of the first absorbent article of the present invention (FIG. 6).
It is.

The first absorbent article of the present invention shown in FIG.
The sanitary napkin 300 as a preferred embodiment of the
It comprises a liquid-absorbable surface layer 1, a liquid-impermeable leak-proof layer 3, and a liquid-retentive absorbent layer 2 interposed between the surface layer and the leak-proof layer.

More specifically, the sanitary napkin 300
Is substantially vertically elongated, and when the sanitary napkin is worn, the surface layer 1 is located on the side in contact with the skin, and the leak-proof layer 3 is located on the side in contact with the underwear.

As will be described later, the absorbent layer 2 includes the first absorbent sheet 100, fluff pulp 2a, and the absorbent paper 2b covering the first absorbent sheet 100 and the fluff pulp 2a. The leak-proof layer 3 is formed of the absorbing layer 2
Side and bottom portions are covered. The surface layer 1 covers all surfaces of the combined body of the absorption layer 2 and the leakage prevention layer 3.

The surface layer 1 is not particularly limited as long as it can transmit a liquid to the absorption layer 2, but preferably has a feeling close to underwear.
Examples of such a surface layer include, for example, a woven fabric, a nonwoven fabric, and a porous film of a thermoplastic resin. In particular, an apertured film made of a polyolefin such as low-density polyethylene can be preferably used.

The leak-proof layer 3 is not particularly limited as long as it is liquid-impermeable, but preferably has moisture permeability and a feeling close to underwear. The liquid-impermeable leakproof layer having moisture permeability is, for example, a thermoplastic resin to which an inorganic compound or an organic compound filler is added,
It can be obtained by melt extruding from a T-die or a circular die to form a film, and then uniaxially or biaxially stretching the film.

On the side in contact with the undergarment of the sanitary napkin 300, two adhesive portions 4, 4 are formed in a streak shape in the longitudinal direction, and the adhesive portions 4, 4 are peeled off before use. Paper 5
Protected by Also, in FIG.
Is a joint for joining the above members. In addition, other points that are not described in detail are configured similarly to the conventional sanitary napkin.

Next, the characteristic portion of the first absorbent article of the first embodiment will be described. The sanitary napkin 300 as the first absorbent article of the first embodiment includes the liquid-retaining absorbent layer 2, which is composed of at least a highly absorbent polymer, a bulky cellulose fiber, and a hydrophilic. The first absorbent sheet 100 containing the fine fibers of the above. The first absorbent sheet 100 is composed of a fiber aggregate and a fiber web, and the fiber aggregate and the fiber web are integrated with each other.
The absorbent fiber has a bulky cellulose fiber having an absorbent surface and not containing the superabsorbent polymer on the absorbent surface side and having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. The web has an average fiber length of 1 to 20
In addition to a bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more in mm and a hydrophilic fine fiber having an average fiber length of 0.02 to 0.5 mm, the hydrophilic fine fiber on one surface side Is higher than the abundance ratio on the other surface side, and is adjacent to the fiber aggregate on the surface side where the abundance ratio of the hydrophilic fine fibers is low, and the superabsorbent polymer is It is characterized in that it is contained inside the sheet and is bonded to the fibers constituting the absorbent sheet.

By using the above-mentioned absorbent sheet,
It is possible to obtain an absorbent article free of superabsorbent polymer falling off and gel blocking. Moreover, such an absorbent sheet has the functions of absorbing, transmitting and diffusing liquid and retaining liquid in its single structure, and therefore has the above-mentioned functions as a conventional liquid absorbent article. Since there is no need to combine members, an extremely thin liquid absorbent article can be obtained.

The first absorbent article of the present invention shown in FIG.
According to a preferred embodiment of the present invention, liquid is absorbed into the sanitary napkin 300 through the surface layer 1. After that, the light is transmitted through the fluff pulp 2a and is absorbed and held by the highly absorbent polymer dispersed in the first absorbent sheet 100. In this case, the first absorbent sheet 100
Is preferably arranged such that the fiber aggregate having the absorption surface is located on the side of the surface layer 1. The first
By arranging the absorbent sheet in this manner, the liquid absorbed by the fluff pulp 2a can be more smoothly absorbed by the first pulp.
The preferred effect of leading to the absorbent sheet 100 is obtained.

As described in detail in the description of the first absorbent sheet 100, the first absorbent sheet 100 can hold a higher absorbent polymer in a larger amount than the conventional absorbent sheet. The sanitary napkin 300 including the first absorbent sheet 100 has a large liquid holding capacity. In addition, since the superabsorbent polymer is three-dimensionally dispersed on the first absorbent sheet, gel blocking does not occur, and the original absorption performance of the superabsorbent polymer can be efficiently exhibited. Even with the use of the superabsorbent polymer described above, a further improved absorption performance can be obtained. Moreover, since the sanitary napkin 300 shown in FIG. 6 includes the fluff pulp 2a in addition to the first absorbent sheet 100, the liquid holding capacity is further increased. Therefore, the first absorbent article of the present embodiment is suitable as a nighttime sanitary napkin worn for a long time.

Next, FIGS. 7 to 11 show second to sixth preferred embodiments of the first absorbent article of the present invention. In the second to sixth embodiments, the same points as those in the first embodiment are not described in detail, but the description in the first embodiment is applied as appropriate. Also, FIG.
11, the same members as those in FIG. 6 are denoted by the same reference numerals.

The second absorbent article of the present invention shown in FIG.
In the sanitary napkin 100 as a preferred embodiment of the present invention, the absorbent layer is composed of only the first absorbent sheet 100, and the side surface and the bottom surface of the first absorbent sheet 100 are covered by the leakproof layer 3. Coated. The surface layer 1 covers all surfaces of the combination of the first absorbent sheet 100 and the leak-proof layer 3. In addition, also in this embodiment, similarly to the first embodiment, the first absorbent sheet 100 is arranged so that the fiber aggregate having the absorbent surface is located on the side of the surface layer 1. Is preferred.

Since the sanitary napkin 300 has a small number of members and each member is thin, it can be an extremely thin sanitary napkin.
Further, since the first absorbent sheet 100 retains a large amount of the high absorbent polymer, the first absorbent sheet 100 is thin,
The liquid holding capacity is large. In addition, since the superabsorbent polymer is three-dimensionally dispersed on the first absorbent sheet, gel blocking does not occur, and the original absorption performance of the superabsorbent polymer can be efficiently exhibited. Even with the use of the superabsorbent polymer described above, a further improved absorption performance can be obtained. As a result, a sanitary napkin having a comfortable wearing feeling, a large liquid holding capacity, and further improved absorption performance can be obtained.

The third absorbent article of the present invention shown in FIG.
In the sanitary napkin 300 as a preferred embodiment of the present invention, the absorbent layer is composed of only the first absorbent sheet 100, and the first absorbent sheet 100 is bent in a C shape. Then, the first absorbent sheet 1
No. 00 has its side and bottom portions covered with the leak-proof layer 3. Further, all surfaces of the combination of the first absorbent sheet 100 and the leak-proof layer 3 are connected to the surface layer 1.
Is coated. In the present embodiment, it is preferable that the first absorbent sheet 100 is folded and disposed so that the fiber aggregate having the absorbent surface is located on the side of the surface layer 1.

The sanitary napkin 300 is provided by the first
The absorbent sheet 100 is thicker than the sanitary napkin shown in FIG. 7 because it is bent in a C shape, but still thinner than the sanitary napkin shown in FIG. can do. Moreover, since the first absorbent sheet 100 is bent in a C-shape, the liquid holding capacity is large. As a result, a sanitary napkin having a comfortable wearing feeling and a large liquid holding capacity can be obtained.

The fourth absorbent article of the present invention shown in FIG.
In the sanitary napkin 300 as a preferred embodiment of the present invention, the absorbent layer comprises the first absorbent sheet 100, 10
,... (Three in FIG. 9). Then, the first absorbent sheet 10 stacked
, 0, 100,... Are covered with the leak-proof layer 3 on the side surface and the bottom surface. Further, the surface layer 1 covers all surfaces of the combination of the first absorbent sheets 100, 100,... And the leak-proof layer 3. In addition, also in this embodiment, similarly to the first embodiment, the first absorbent sheet 100 is arranged so that the fiber aggregate having the absorbent surface is located on the side of the surface layer 1. Is preferred.

The sanitary napkin 300 is provided by the first
The thickness of the absorbent sheet 100 is thicker than that of the sanitary napkin shown in FIG.
The sanitary napkin shown in FIG. 6 using fluff pulp for the absorbent layer 2 can be made thinner. Moreover, the first
Since a plurality of the absorbent sheets 100 are stacked, the liquid holding capacity is large. As a result, a sanitary napkin having a comfortable wearing feeling and a large liquid holding capacity can be obtained.

In the sanitary napkin 300 as a fifth preferred embodiment of the first absorbent article according to the present invention shown in FIG. 10, the first absorbent sheet 100 has a surface layer capable of absorbing liquid and a liquid retaining property. (That is, the absorbent article includes a liquid-retentive absorbing layer and a liquid-impermeable leakage-preventing layer). That is, the sanitary napkin 300 of the present embodiment has a first absorbent sheet 1 in which a liquid-absorbable surface layer and a liquid-retentive absorbent layer are integrated.
The first absorbent sheet 100 has a side surface and a bottom surface covered with the leak-proof layer 3. In the present embodiment, it is particularly preferable to arrange the first absorbent sheet 100 so that the fiber aggregate having the absorbent surface is located on the side in contact with the skin.

In the sanitary napkin 300, the number of components is reduced, and the thickness can be further reduced. As a result, a sanitary napkin that has a comfortable wearing feeling and can be manufactured with a simple process and at low cost is obtained.

In the sanitary napkin 300 as the sixth preferred embodiment of the first absorbent article of the present invention shown in FIG. 11, the first absorbent sheet has a liquid-absorbable surface layer, It also has three functions of an absorption layer and a liquid-impermeable leak-proof layer. That is, the sanitary napkin 300 of this embodiment is formed by integrating a liquid-absorbable surface layer, a liquid-retentive absorbing layer, and a liquid-impermeable leakproof layer. More specifically, the first absorbent sheet 100 and the surface of the absorbent sheet which are opposite to the liquid-absorbing surface are bonded to each other.
It comprises an integrated liquid impermeable sheet 3 '.
In the present embodiment, the first absorbent sheet 1
00 is particularly preferably arranged such that the fiber aggregate having the absorbing surface is located on the side that absorbs the liquid, and the liquid impermeable sheet 3 ′ is bonded to the surface opposite to the absorbing surface. .

In the sanitary napkin 300, the number of constituent members is reduced, and the thickness can be further reduced. As a result, a sanitary napkin that has a more comfortable wearing feeling and that can be manufactured with a simpler process at a low cost is obtained. The first absorbent article of the present embodiment is also suitable as an absorbent article having a small amount of liquid absorption, such as a breast milk pad or a hygiene pad, in addition to a sanitary napkin as shown in FIG.

Next, a preferred embodiment of the second absorbent article of the present invention will be described. A preferred embodiment of the second absorbent article according to the present invention is the same as the first to sixth embodiments (FIGS. 6 to 11) described above with respect to the first absorbent article, in place of the first absorbent sheet. The second absorbent sheet is used. That is, the first absorbent sheet 100 in the sanitary napkin 300 shown in FIGS.
Instead, an absorbent article using the second absorbent sheet corresponds to the second absorbent article. Therefore, as for the details of the second absorbent article, the detailed description of the first absorbent article and the description of FIGS. 6 to 11 are appropriately applied.

As described above, the first absorbent article and the second absorbent article according to the present invention have been described with reference to a sanitary napkin as a preferred embodiment. The present invention can be similarly applied to other absorbent articles such as pads, disposable diapers, medical pads and breast milk pads. Further, as long as the requirements of the present invention are not deviated, the constituent materials and the manufacturing method of the absorbent article can be freely modified within the scope of the prior art.

[0162]

Next, the present invention will be described more specifically with reference to examples. First, used in Examples and Comparative Examples,
Production of bulky cellulose fibers and hydrophilic fine fibers will be described. In the following description, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively, unless otherwise specified.

[Production Example 1] The production average fiber length of bulky cellulose fiber was 2.35 mm, and the fiber roughness was 0.36 m.
g / m, and a mercerized pulp having a roundness of the fiber cross section of 0.80 [POROSA manufactured by ITT RAYONIER INC.
NIER-J "(trade name)] and 5% dimethylol dihydroxyethylene urea [crosslinking agent," Sumitex Resin NS-19 "(trade name) manufactured by Sumitomo Chemical Co., Ltd.) and 3% metal salt Catalyst [Sumitex manufactured by Sumitomo Chemical Co., Ltd.
Accelerator X-110 "(trade name)]
The resulting mercerized pulp was impregnated with the crosslinking agent.

Next, the cross-linking agent aqueous solution was separated from the mercerized pulp until the amount of the cross-linking agent aqueous solution with respect to the mercerized pulp became 200%, and then heated at 135 ° C. for 10 minutes in an electric dryer. Cellulose in the mercerized pulp was crosslinked to obtain a mercerized crosslinked pulp. This is referred to as a cellulose fiber (A).

[Production Example 2] The average production fiber length of bulky cellulose fibers was 2.38 mm, and the fiber roughness was 0.32 m.
g / m and a fiber cross-section having a roundness of 0.30 [cross-linked pulp [HighBulk Add made by Weyerhauser Paper]
itive HBA-S "(trade name)]. This is referred to as a cellulose fiber (B).

[Production Example 3] Production average bulk length of bulky cellulose fiber is 2.56 mm and fiber roughness is 0.24 m
A softwood kraft pulp ["HARMAC-R" (trade name) manufactured by MacMillan Bloedel Ltd.] having a g / m and a roundness of a fiber cross section of 0.34 was prepared. This is referred to as a cellulose fiber (C). The cellulose fibers (C) are not crosslinked.

The average fiber length, fiber roughness and roundness of the cross section of the cellulose fibers (A) to (C) were measured by the following methods. Table 1 shows the results.

<Measurement of Average Fiber Length and Fiber Roughness> Measurement was performed using a fiber roughness meter FS-200 (manufactured by KAJAANI ELECTRONICS LTD.). First, in order to determine the true weight of the cellulose fiber, the cellulose fiber was heated at 100 ° C. in a vacuum dryer.
For 1 hour to remove the moisture present in the cellulose fibers. Quickly measure about 1 g of cellulose fiber accurately to ± 0.1 mg. Next, in order not to damage the cellulose fiber, the cellulose fiber is completely disintegrated in 150 ml of water with a mixer attached to the fiber roughness meter,
This was diluted with water to 5000 ml, and 50 ml was accurately weighed from the obtained diluent, used as a fiber roughness measurement solution, and the average fiber length and fiber roughness were determined according to the operation procedure of the fiber roughness meter. Was. The average fiber length used was a value calculated by the following equation based on the above operation.

[0169]

(Equation 1)

<Measurement of Roundness of Fiber Cross Section> The roundness of the cellulose fiber cross section was measured by first slicing the cellulose fiber perpendicularly to the cross sectional direction so that the cross section of the cellulose fiber did not change. A cross-sectional photograph was taken with a microscope, and the cross-sectional photograph was analyzed with an image analyzer [Avio EXCEL (trade name) manufactured by Nippon Avionics Co., Ltd.], and the roundness of the cellulose fiber cross-section was determined using the following equation. . The roundness was determined by measuring 100 points of an arbitrary cellulose fiber cross section and calculating the average value.

[0171]

(Equation 2)

[0172]

[Table 1]

[Production Example 4] Production of hydrophilic fine fibers Cellulose fine fibers having an average fiber length of 0.12 mm obtained by hydrolyzing selected pulp with acid, washing with water and drying, and then pulverizing finely by mechanical pulverization [Sanyo Kokusaku "KC Floc W-100" (trade name) manufactured by Pulp Co., Ltd.] was prepared. This is referred to as hydrophilic fine fiber (D).

Example 1 Production of Absorbent Sheet The concentration of cellulose fiber (A) was 0.16%, the concentration of hydrophilic fine fiber (D) was 0.03%, and the average fiber was 1 denier. The concentration of the polyvinyl alcohol fiber having a length of 3 mm (heat-fusible adhesive fiber, hereinafter referred to as PVA, Fibribond (trade name) manufactured by Sansho Co., Ltd.) is 0.01%. 20%) and uniformly dispersed in water to obtain a slurry.

The slurry was used to prepare a wire opening having a diameter of 90 μm.
(166 mesh) on a wire mesh papermaking wire.
A paper layer was formed on the wire mesh papermaking wire. Suctionbo
6 liters / m^Two・ This paper at speed of sec
The layer is dewatered and the basis weight is 70 g / m ^TwoTo become a fiber web
Was formed.

This fiber web contains 80 parts of the cellulose fiber (A), 15 parts of the hydrophilic fine fiber (D), and 5 parts of the PVA fiber based on 100 parts of the fiber web. As shown in FIG. 5, the ratio of the presence of the hydrophilic fine fibers (D) on one side is high, and the ratio of the presence of the hydrophilic fine fibers (D) on the other side is low. The liquid has a diffusion gradient such that the higher the proportion of the hydrophilic fine fibers (D) is, the larger the liquid diffusion is, and the smaller the liquid diffusion is on the opposite side.

Next, the fiber web was dried with a suction box based on 100 parts of the dry fiber web.
Portion, the fiber web is dewatered, and furthermore, the surface of the wet fibrous web after dehydration by pressing is provided with a superabsorbent polymer [Nippon Shokubai (Nippon Shokubai ( Co., Ltd., Aquaric CAW-4 (trade name)] was sprayed almost uniformly at a spray basis weight of 50 g / m ² .

Of the above-mentioned fiber web, a fiber aggregate having a basis weight of 30 g / m ² previously made with the following composition was overlapped on the surface on which the superabsorbent polymer was sprayed. The superposed body was introduced into a dryer, dried and integrated at a temperature of 130 ° C. to obtain one absorbent sheet having a highly absorbent polymer fixed therein. This is designated as an absorbent sheet (A).

The fiber aggregate preliminarily made was produced by the following method. That is, the concentration of the cellulose fiber (A) is:
These were uniformly dispersed in water to obtain a slurry so that the concentration of the PVA fibers was 0.194% and the concentration of the PVA fibers was 0.006% (the total slurry was 0.20%). This slurry was sprayed on a wire mesh papermaking wire having a wire opening diameter of 90 μm (166 mesh) to form a paper layer on the wire mesh papermaking wire. This paper layer was dehydrated and dried at a rate of 6 liters / m ² · sec using a suction box to produce a fiber aggregate having a basis weight of 30 g / m ² . This fiber assembly contained 97 parts of the cellulose fiber (A) and 3 parts of the PVA fiber based on 100 parts of the fiber assembly.

Example 2 Production of Absorbent Sheet First, as a fibrous web, the concentration of the cellulose fiber (B) was 0.194%, and the concentration of the PVA fiber was 0.1%.
006% (0.20 in total slurry)
%) And these were uniformly dispersed in water to obtain a slurry. This slurry was used to prepare a wire having an opening diameter of 90 μm (16 μm).
(6 mesh) to form a paper layer on the wire mesh papermaking wire. This paper layer was dehydrated at a speed of 6 liters / m ² · sec using a suction box, and a fiber web was formed so as to have a basis weight of 30 g / m ² . Based on 100 parts of the fiber web, 97 parts of the cellulose fiber (B) and the PVA
It contained 3 parts of fiber.

Next, the fiber web was weighed with a suction box based on 100 parts of the dry fiber web.
And dehydrated until part.

Subsequently, immediately before the press part, a highly absorbent polymer [Aqualic CAW-4 (trade name) manufactured by Nippon Shokubai Co., Ltd.] was sprayed on the wetted fiber web after dehydration, and the basis weight was 50 g / m 2. Spread almost uniformly with ² .

Of the fiber web, a fiber aggregate having a basis weight of 70 g / m ² , which was previously made with the following composition, was superposed on the surface on which the superabsorbent polymer was sprayed. The superposed body was introduced into a dryer, dried and integrated at a temperature of 130 ° C. to obtain one absorbent sheet having a highly absorbent polymer fixed therein. This is designated as an absorbent sheet (B).

The fiber aggregate preliminarily made was manufactured by the following method. That is, the concentration of the cellulose fiber (A) is 0.16%, the concentration of the hydrophilic fine fiber (D) is 0.03%, and the concentration of the PVA fiber is 0.01% (slurry). These were uniformly dispersed in water to obtain a slurry.

This slurry was used to prepare a wire having an opening diameter of 90 μm.
m (166 mesh) on a wire mesh papermaking wire,
A paper layer was formed on the wire mesh papermaking wire. This paper layer was dehydrated and dried at a speed of 6 liters / m ² · sec using a suction box to form a fiber aggregate so as to have a basis weight of 70 g / m ² .

In this fiber assembly, 80 parts of the cellulose fiber (A), 15 parts of the hydrophilic fine fiber (D), and 5 parts of the PVA fiber based on 100 parts of the fiber assembly.
Parts. As shown in FIG. 5, this fiber aggregate has a high percentage of the hydrophilic fine fibers (D) on the side adjacent to the wire mesh papermaking wire and the hydrophilic fine fibers (D) on the other side. Is low. The liquid has a diffusion gradient such that the higher the proportion of the hydrophilic fine fibers (D) is, the larger the liquid diffusion is, and the smaller the liquid diffusion is on the opposite side.

Example 3 Production of Absorbent Sheet From the composition shown in Table 2, an absorbent sheet was obtained in the same manner as in Example 1. This is designated as an absorbent sheet (C).

Comparative Example 1 Production of Absorbent Sheet A fiber web having the following composition and a basis weight of 70 g / m ² was prepared beforehand. That is, the concentration of the cellulose fiber (C) is 0.1
6%, the concentration of the hydrophilic fine fibers (D) is 0.03
% And the above-mentioned PVA fiber concentration was 0.01% (0.20% as a whole slurry), and these were uniformly dispersed in water to obtain a slurry.

[0189] This slurry was used to prepare a wire opening having a diameter of 90 µm.
(166 mesh) was sprinkled on a wire mesh papermaking wire to form a paper layer on the wire mesh papermaking wire. Using a suction box, the paper layer was dehydrated and dried at a speed of 6 liter / m ² · sec, and paper was made to have a basis weight of 70 g / m ² . This fiber web contained 80 parts of the cellulose fiber (C), 15 parts of the hydrophilic fine fiber (D), and 5 parts of the PVA fiber based on 100 parts of the fiber web. The cellulose fiber (C) blended in the fiber web cannot have a bulky network structure because the fiber roughness is less than 0.3 mg / m.
The hydrophilic fine fiber (D) is the cellulose fiber (C)
Since it cannot pass through the inside, the hydrophilic fine fibers (D) are compounded almost uniformly in the thickness direction and have no liquid diffusion gradient.

Next, water was sprinkled to 200 parts based on 100 parts of the fiber web (dry), and then a highly absorbent polymer [Nippon Shokubai Co., Ltd.] was placed on the wet fiber web.
AQUALIC CAW-4 (trade name)]
/ M ² was sprayed almost uniformly.

Of the above-mentioned fiber web, a fiber aggregate having a basis weight of 30 g / m ² previously made with the following composition was superposed on the surface on which the superabsorbent polymer was sprayed. And then dried with a drier to obtain a total basis weight of 150 g / m ^2.
Was obtained. This is designated as an absorbent sheet (D). The fiber web in which the superabsorbent polymer is sprayed in the absorbent sheet (D) is not a wet fiber web, but the fibers forming the fiber web are strongly bound to each other. Moreover, the absorbent sheet (D) is a layer in which a highly absorbent polymer is sandwiched between the fiber web and the fiber aggregate.

The fiber aggregate preliminarily made was produced by the following method. That is, these are uniformly dispersed in water so that the concentration of the cellulose fiber (C) is 0.19% and the concentration of the PVA fiber is 0.01% (0.20% as a whole slurry). I got

This slurry was used to prepare a wire having an opening diameter of 90 μm.
m (166 mesh) on a wire mesh papermaking wire,
A paper layer was formed on the wire mesh papermaking wire. Using a suction box, the paper layer was dehydrated and dried at a speed of 6 liters / m ² · sec to form a fiber aggregate so as to have a basis weight of 30 g / m ² .

The fiber assembly was composed of 95 parts of the cellulose fiber (C) based on 100 parts of the fiber assembly,
A fiber contained 5 parts.

Comparative Example 2 Production of Absorbent Sheet A highly absorbent polymer [Nippon Shokubai Co., Ltd.] was placed between pulp sheets having a basis weight of 45 g / m ² formed by the air laid method.
Manufactured by Aquaric CAW-4 (trade name)] with a basis weight of 50 g / m
Then, the absorbent sheet was sprayed so as to obtain No. ² , and then an absorbent sheet having pulp fixed with a chemical binder was produced. This absorbent sheet is referred to as an absorbent sheet (E).

Comparative Example 3 Production of Absorbent Sheet A dry absorbent sheet containing a synthetic pulp and a superabsorbent polymer was produced. That is, polyethylene synthetic pulp 25
And a pulp sheet composed of 75 parts of chemical pulp are fibrillated with a hammer mill to form a dry absorbent sheet having a basis weight of 100 g / m ² , a highly absorbent polymer [Aqualic manufactured by Nippon Shokubai Co., Ltd. CAW-4 (brand name)]
m ^2, and the resulting mixture was mixed with polyethylene raw pulp by hot air treatment to be integrated. This dry-type absorbent sheet has a total basis weight of 150 g / m ² , and has a super-absorbent polymer on its surface. This absorbent sheet is referred to as an absorbent sheet (F).
The chemical pulp is a general cellulose fiber (softwood kraft pulp) that is neither bulky nor fine.

Absorbent sheet (A) in Examples 1 to 3
To (C) and the absorption sheets (D) in Comparative Examples 1 to 3
Tables 2 and 3 show the composition and production method of (F).

[0198]

[Table 2]

[0199]

[Table 3]

Absorbent sheet (A) in Examples 1 to 3
To (C) and the absorption sheets (D) in Comparative Examples 1 to 3
Regarding (F), in order to evaluate the immobilizing ability and the absorption performance of the superabsorbent polymer, the thickness, the drop-off test of the superabsorbent polymer, the saturated absorption amount, the absorption rate, and the liquid return amount were measured by the following methods. . Table 4 shows the results.

<Thickness> A load of 2.5 g / cm ² was applied to the upper surface of the absorbent sheet cut to an appropriate size, and the thickness was measured. The average value of a total of 10 points was taken as the thickness.

<Drop test of superabsorbent polymer> 70 × 2
After measuring the weight of the absorbent sheet cut to 00 mm,
This is placed in a plastic bag with a length of 280 mm and a width of 200 mm with a chuck, and in this state, vibration is given by shaking 50 times by hand. After completion of the test, the change in weight of the absorbent sheet was measured, and the colored water stained with blue No. 1 (0.3%) was used so that the superabsorbent polymer dropped into the plastic bag could be easily observed with the naked eye.
g / 100 ml of water) in a plastic bag to swell the superabsorbent polymer and visually determine the degree of shedding. O: Almost no dropout of the superabsorbent polymer was observed. Δ: Some loss of the superabsorbent polymer was observed. ×: Dropping of the superabsorbent polymer is considerably observed. The measurement was performed ten times, and the average value was defined as the amount of dropout.

<Saturation Absorption Amount> An absorbent sheet of 5 cm square was put in a bag made of nonwoven fabric, and the bag was immersed in ion exchange water for 10 minutes. After the bag is taken out of the ion-exchanged water, it is hung in the air for one hour, the attached water is dropped, the weight is measured, and the weight increase per gram of the absorbent sheet is determined as the saturated absorption amount (g / g). ).

<Absorption speed> As shown in FIG.
A transparent acrylic plate 20 of 10 cm square and a weight 22 having a hole of 1 cm in diameter are placed on the center of the corner absorbent sheet 100, and a load of 5 g / cm ² is applied to the absorbent sheet 100. And 20 ml of physiological saline was injected through the filter, and the time required for absorbing the physiological saline was defined as the absorption rate. The measurement of the absorption rate was performed twice, but the second injection (reabsorption rate) was performed one minute after the first measurement.

<Measurement of liquid return amount> After measuring the absorption rate, 1
As shown in FIG. 14, 10 sheets of 15 cm square filter paper 24 (Toyo filter paper TYPE 2) are stacked on the absorbent sheet 100 after 0 minutes, and a 15 cm square acrylic plate 26 and a weight 2 are further placed thereon.
2 was applied for 1 minute so as to give a load of 50 g / cm ² , then the filter paper 24 was taken out, and the weight of the physiological saline absorbed by the filter paper 24 was defined as the liquid return amount.

[0206]

[Table 4]

Example 4 Production of Absorbent Article A sanitary napkin having the structure shown in FIG. 8 was produced . That is, as the absorbent sheet 100, the absorbent sheet (A) having a length of 175 mm and a width of 145 mm was bent and compressed in a C-shape so that both side edges faced almost at the center of the absorber, and the width was 73 mm. This absorbent sheet (A) was used as an absorber.
Polyamide waterproof paper (length 205 mm, width 95) as leak-proof layer 3
mm), the side surface and the bottom surface of the obtained absorbent sheet were covered with such a waterproofing paper. All the surfaces of the combined body of the absorbent sheet and the polylaminate waterproof paper are coated with a liquid-absorbable surface layer 1 (length 205 mm, width 172
mm), and these members were fixed by the hot melt adhesive used as the fixing agent 6. Further, ^two hot-melt pressure-sensitive adhesives having a basis weight of 30 g / m ² , a width of 20 mm, and a length of 115 mm were applied to the opposite side of the surface material 1 as adhesive portions 4. Thus, a sanitary napkin having the configuration shown in FIG. 8 was obtained. In addition, as the surface layer 1, a polyethylene apertured film was used. This surface layer 1 has a basis weight of 30.
g / m ² of polyethylene film with perforations having a pore diameter of 0.5 mm and a pore area ratio of 20 mm.
It is the one that has a hole.

[Examples 5 and 6] Preparation of absorbent article Example 4 was repeated except that the absorbent sheets (B) and (C) were used instead of the absorbent sheet (A) used in Example 4. In the same manner as in the above, a sanitary napkin having the configuration shown in FIG. 8 was obtained.

Comparative Example 4 Production of Absorbent Article A sanitary napkin having the structure shown in FIG. 15 was produced . That is,
Length 1 adjusted to a thickness of 4.5 mm with a basis weight of 300 g / m ²
After spraying a small amount of water on the flap pulp 2a having a width of 75 mm and a width of 73 mm, a superabsorbent polymer 2e [Aqualic CAW-4 (trade name) manufactured by Nippon Shokubai Co., Ltd.] is 60 m wide.
Approximately 0.53 g was sprayed almost uniformly over an area having a length of 175 mm and a width of 175 mm to give a basis weight of 50 g / m ² . On top of this, a wet absorbent paper 2b made of wood pulp having a basis weight of 18 g / m ² and a length of 175 mm and a width of 73 mm is superimposed, and all surfaces of these combined bodies are weighed 18 g / m ² and a length of 175 mm. Width 130
An integrated absorbent layer 2 was formed by coating with a wet-type absorbent paper 2c made of wood pulp of mm. Thereafter, a sanitary napkin having the configuration shown in FIG. 15 was produced in the same manner as in Example 3.

Production of Absorbent Articles [Comparative Examples 5 to 7] Absorbent sheet (A) used in Example 4
Was used in the same manner as in Example 4 except that the absorbent sheets (D) to (F) were used instead of, to obtain a sanitary napkin having the configuration shown in FIG.

With respect to the sanitary napkins of Examples 4 to 6 and Comparative Examples 4 to 7, in order to evaluate the ability to immobilize the polymer and the absorption performance, the following methods were used to remove the polymer, the product thickness, the absorption time, and the dynamic liquid. A return amount and a leak test were performed for each sanitary napkin. The results are shown in Table 5 below.

<Detachment test of superabsorbent polymer>
After weighing the sanitary napkins of Nos. 6 to 6 and Comparative Examples 4 to 7, the napkins were placed in a plastic bag with a chuck having a length of 280 mm and a width of 200 mm, and shaken by hand 50 times in this state. After completion of the test, the change in weight of the sanitary napkin was measured, and the colored water (0.3 g / water 100 ml) dyed with Blue No. 1 was used so that the superabsorbent polymer dropped into the plastic bag could be easily observed with the naked eye. In addition to swelling the superabsorbent polymer in the plastic bag, the degree of shedding is visually determined. O: Almost no dropout of the superabsorbent polymer was observed. Δ: Some loss of the superabsorbent polymer was observed. ×: Dropping of the superabsorbent polymer is considerably observed. The measurement is performed 10 times, and the average value is defined as the dropout amount.

<Measurement of Product Thickness> As shown in FIG.
Ten sanitary napkins were superimposed, an acrylic plate weighing 500 g was placed from above, and the thickness of the ten sanitary napkins was measured to determine the product thickness per sheet.

<Absorption time (5 g), re-absorption time (10
g) Measurement of Dynamic Liquid Return Amount> An absorption rate measuring device shown in FIG. 13 was used. That is, the absorbent sheet 1 shown in FIG.
In place of 00, the sanitary napkins obtained in Examples 4 to 6 and Comparative Examples 4 to 7 were placed horizontally, an acrylic plate 20 having a 1 cm diameter injection port was placed thereon, and a weight 22 was placed thereon. A load of 5 g / cm ² was applied to the sanitary napkin. Next, 5 g of defibrillated horse blood (manufactured by Nippon Biotest Laboratory Co., Ltd.) is injected through the inlet, and the absorption time (second) until the defibrillated horse blood is completely absorbed is determined. After the defibrillated horse blood was completely absorbed, it was left as it was for 20 minutes, 5 g of defibrillated horse blood was injected again, the reabsorption time (10 g) was determined, and the same was left for 20 minutes. After that, basis weight 30g / m
² length 195 mm, 10 sheets of absorbent paper made of softwood kraft pulp having a width 75 mm, placed on the top surface of the sanitary napkin (skin contact surface side), a movable female waist model 90 shown in FIG. 17
Then, as shown in FIG. 18, shorts equipped with a sanitary napkin 80 were put on, and then walking was performed for one minute at a walking speed of 100 seconds / minute (50 m / minute). After walking, the sanitary napkin 80 and ten pieces of absorbent paper were taken out, and the weight of the defibrated horse blood absorbed by the absorbent paper was determined as a liquid return amount (g).
The measurement was carried out for each of the five points, and the respective average values were obtained, which were taken as the absorption time, re-absorption time, and dynamic liquid return amount.

<Leak Test (Number of Occurrences of Leaks)>
6 and sanitary napkins 80 obtained in Comparative Examples 4 to 7,
As shown in FIG. 18, after attaching to the movable female waist model 90 and putting on shorts, 100 steps / minute (50 m /
Minutes) at a walking speed of 10 minutes. Then, while walking, 5 g of the defibrillated horse blood was injected into the sanitary napkin 80 by the tube 91, and then the gait was allowed to walk at the same speed for 20 minutes (5 g absorption), and thereafter the defibrillated horse blood 5
g was infused for 20 minutes at the same speed (1
At each time point, the number of leaked sheets out of the 10 samples was counted.

[0216]

[Table 5]

As is evident from the results shown in Tables 4 and 5, the absorbent article of the present invention using a specific absorbent sheet was prepared using a conventional absorbent sheet (water spraying, embossing integration or integration with an adhesive). (Absorbent sheet obtained in (1)), the absorption rate of the superabsorbent polymer is superior to that of the absorbent article, and the absorption rate and liquid return amount even when using an ultrathin absorbent sheet having a thickness of 1 mm or less. It can be seen that the absorptive characteristics of the compound are excellent. Further, the absorbent article of the present invention has a very simple structure, but has a very high liquid absorption time, a small amount of liquid return, and a small number of leak occurrences, and has extremely high performance. . This is because the absorbent sheet used in the absorbent article of the present invention has a liquid absorption / diffusion gradient in its single structure, so that it absorbs the liquid quickly and smoothly passes through the absorbent sheet. This is because the liquid permeates and the liquid diffuses sufficiently.

[0218]

As described above in detail, according to the present invention, the superabsorbent polymer is securely fixed in the sheet, the superabsorbent polymer hardly falls off, and gel blocking of the superabsorbent polymer occurs. A difficult absorbent sheet is obtained. The absorbent sheet has three functions of permeation / diffusion / retention of a liquid in a single structure, and is excellent in both absorption speed and absorption power.

Further, according to the preferred method for producing the absorbent sheet of the present invention, the production process is greatly accelerated as compared with the conventional absorbent sheet production method. Further, a complicated processing process for fixing the superabsorbent polymer is not required, and the manufacturing process is extremely simplified.

Further, according to the above-mentioned production method, not only the superabsorbent polymer can be dispersed throughout the absorbent sheet but also can be partially dispersed in a streak shape in the longitudinal direction or intermittently dispersed in the longitudinal direction. Therefore, the range in which the superabsorbent polymer is sprayed can be set according to the application, and the absorbent sheet can be manufactured more economically.

Further, according to the present invention, it is possible to provide an extremely thin absorbent article in which a large amount of superabsorbent polymer is fixed despite being extremely thin. In addition, the absorbent article has a high liquid absorption rate, a small liquid return amount, and a small number of leaks. In particular, when the absorbent layer is composed of only the absorbent sheet, the absorbent article can be manufactured only by cutting one sheet of the absorbent sheet, and the absorbent article can be manufactured at a high speed by a very simple manufacturing process. Can produce. Further, since the absorbent sheet has an integrated structure, even if the absorbent article provided with the absorbent sheet is worn and exercised violently, the high absorbent polymer can absorb the absorbent article. There is no decrease in absorption performance due to separation from the sheet.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a first absorbent sheet of the present invention.

FIG. 2 is a schematic view showing a cross section of a second absorbent sheet of the present invention.

FIG. 3 is a schematic view showing an apparatus preferably used for producing the first absorbent sheet of the present invention.

FIG. 4 is a schematic view showing an apparatus preferably used for producing the second absorbent sheet of the present invention.

FIG. 5 is a schematic view showing a cross section of a fiber web formed on a papermaking wire.

FIG. 6 is a schematic view showing a cross section of a sanitary napkin as a first embodiment of the first absorbent article according to the present invention.

FIG. 7 is a schematic view showing a cross section of a sanitary napkin as a second embodiment of the first absorbent article according to the present invention.

FIG. 8 is a schematic view showing a cross section of a sanitary napkin as a third embodiment of the first absorbent article according to the present invention.

FIG. 9 is a schematic view showing a cross section of a sanitary napkin as a fourth embodiment of the first absorbent article according to the present invention.

FIG. 10 is a schematic view showing a cross section of a sanitary napkin as a fifth embodiment of the first absorbent article according to the present invention.

FIG. 11 is a schematic view showing a cross section of a sanitary napkin as a sixth embodiment of the first absorbent article according to the present invention.

FIG. 12 is a schematic view showing a cross section of a conventional absorbent sheet.

FIG. 13 is a schematic diagram showing measurement of absorption time.

FIG. 14 is a schematic diagram illustrating measurement of a liquid return amount.

FIG. 15 is a schematic view showing a cross section of a conventional sanitary napkin.

FIG. 16 is a schematic view illustrating measurement of the thickness of a sanitary napkin.

FIG. 17 is a diagram illustrating a movable female waist model.

FIG. 18 is a schematic diagram showing a state in which a sanitary napkin is attached to a crotch part of a movable female waist model.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 First absorbent sheet 200 Second absorbent sheet 300 First absorbent article 102, 202 Absorbing surface 105, 205 Fiber aggregate 106, 206 Superabsorbent polymer 107, 207 Transmission layer 108, 208 Fiber web 109, 209 Diffusion layer

──────────────────────────────────────────────────続 き Continuing from the front page (72) Minoru Nakanishi Minoru 2606, Akabane, Kaiga-cho, Haga-gun, Tochigi Pref. In Kao Co., Ltd. (56) References JP-A-63-122452 (JP, A) JP-A-55-21203 ( JP, A) JP-A-61-76366 (JP, A) JP-A-57-12638 (JP, A) JP-A-59-135149 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 A61F 13/15-13/84 B01J 20/26

Claims (12)

(57) [Claims] 1. An absorbent sheet comprising at least a super absorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, wherein said absorbent sheet comprises a fiber aggregate and a fiber web. The fiber aggregate is integrated with the fiber web, and the fiber aggregate has an absorbent surface, does not contain the superabsorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 20 mm and a fiber coarseness. The fiber web mainly comprises bulky cellulose fibers having a degree of not less than 0.3 mg / m, and the fiber web has a mean fiber length of 1 to 20 mm and a roughness of not less than 0.3 mg / m and a mean fiber length of 0. .02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one side is higher than the proportion on the other side; The surface ratio of the water-based fine fibers is low and adjacent to the fiber aggregate, and the superabsorbent polymer is contained in the absorbent sheet and the fibers constituting the absorbent sheet An absorbent sheet characterized by being adhered. 2. An absorbent sheet comprising at least a super absorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, wherein said absorbent sheet comprises a fiber aggregate and a fiber web. The fiber aggregate is integrated with the fiber web, and the fiber aggregate has an absorbent surface, does not contain the superabsorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 20 mm and a fiber coarseness. Containing a bulky cellulose fiber having a degree of not less than 0.3 mg / m and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and having an existing ratio of the hydrophilic fine fibers on one surface side. Higher than the existing ratio on the other surface side, the fiber web is mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and the fiber aggregate The surface side where the proportion of the hydrophilic fine fibers present in the body is high is adjacent to the fiber aggregate, and the superabsorbent polymer is contained inside the absorbent sheet and the absorbent sheet is An absorbent sheet, which is adhered to constituent fibers. 3. The absorbent sheet according to claim 1, wherein the superabsorbent polymer is contained in the fiber web. 4. The mixing ratio of the bulky cellulose fiber and the hydrophilic fine fiber in the fiber web is as follows:
The absorbent sheet according to claim 1, wherein the bulky cellulose fiber is 50 to 97 parts by weight and the hydrophilic fine fiber is 3 to 50 parts by weight based on 100 parts by weight of the fiber web. 5. The blending ratio of the bulky cellulose fiber and the hydrophilic fine fiber in the fiber assembly,
The absorbent sheet according to claim 2, wherein the bulky cellulose fiber is 50 to 97 parts by weight and the hydrophilic fine fiber is 3 to 50 parts by weight based on 100 parts by weight of the fiber assembly. 6. The absorbent sheet according to claim 1, wherein the bulkiness of the bulky cellulose fiber has a roundness of a fiber cross section of 0.5 to 1. 7. The absorbent sheet according to claim 1, wherein the bulky cellulose fiber is a crosslinked cellulose fiber. 8. The method for producing an absorbent sheet according to claim 1, wherein the bulky cellulose fiber has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and an average fiber length of 0.02. ~
The wet fibrous web, comprising 0.5 mm of hydrophilic fine fibers, wherein the proportion of the hydrophilic fine fibers on one side is higher than the proportion on the other side; A high-absorbency polymer is sprayed on the surface where the proportion of fine fibers is low, and the average fiber length is 1 to 20 mm and the fiber roughness is 0.3 mg
A method for producing an absorbent sheet, comprising a step of laminating a fiber aggregate mainly composed of bulky cellulose fibers having a mass of at least / m and drying and integrating them. 9. The method for producing an absorbent sheet according to claim 2, wherein the wet fibers mainly comprise bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Sprinkle superabsorbent polymer on the web, and on top of it, average fiber length 1-20mm and fiber roughness 0.3m
g / m or more bulky cellulosic fibers and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the presence ratio of the hydrophilic fine fibers on one surface side is the other. A fiber aggregate higher than the abundance ratio on the surface side, the surface side where the hydrophilic fine fiber abundance ratio is high and the fiber web are overlapped so that they are adjacent to each other, and these are dried and integrated. A method for producing an absorbent sheet, comprising: 10. The fiber web is formed in a forming part, the fiber web is dehydrated in a suction dewatering step, the superabsorbent polymer is sprayed on the fiber web immediately before a press part, and the fiber aggregate is formed thereon. 10. A method according to claim 8 or claim 9, comprising the step of superimposing the bodies and then drying and integrating them with a drier. 11. An absorbent article having a liquid-absorbable surface layer, a liquid-retentive absorbing layer and a liquid-impermeable leakproof layer, wherein the surface layer or the absorbent layer or the absorbent layer of the leakproof layer. On the side, at least a highly absorbent polymer, an absorbent sheet containing bulky cellulose fibers and hydrophilic fine fibers is included, and the absorbent sheet is composed of a fiber aggregate and a fiber web, The fiber aggregate and the fiber web are integrated, and the fiber aggregate has an absorbent surface, does not contain the high-absorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 20 mm. The fiber web is mainly composed of bulky cellulose fibers having a roughness of 0.3 mg / m or more, and the fiber web has a mean fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Including hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, the proportion of the hydrophilic fine fibers present on one side is higher than the proportion present on the other side, and The high-absorbent polymer is contained inside the absorbent sheet and the fibers constituting the absorbent sheet An absorbent article characterized by being adhered. 12. An absorbent article having a liquid-absorbable surface layer, a liquid-retentive absorbent layer, and a liquid-impermeable leakproof layer, wherein the surface layer, the absorbent layer, or the absorbent layer of the leakproof layer. On the side, at least a highly absorbent polymer, an absorbent sheet containing bulky cellulose fibers and hydrophilic fine fibers is included, and the absorbent sheet is composed of a fiber aggregate and a fiber web, The fiber aggregate and the fiber web are integrated, and the fiber aggregate has an absorbent surface, does not contain the high-absorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 20 mm. A bulky cellulose fiber having a roughness of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the presence of the hydrophilic fine fibers on one surface side; The combination is higher than the existing ratio on the other surface side, and the fiber web is mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and The surface where the proportion of the hydrophilic fine fibers is high is adjacent to the fiber aggregate, and the superabsorbent polymer is contained inside the absorbent sheet and constitutes the absorbent sheet. An absorbent article characterized by being adhered to a fiber.