JPH08229071A - Absorbent article - Google Patents

Abstract

PURPOSE: To provide the absorbent paper having high absorbing permeability of a liquid and high diffusibility of the liquid by forming the absorbent paper of an absorber with bulky cellulose fibers and hydrophilic fine fibers, and setting the abundance ratio of the hydrophilic fine fibers higher on one face side of the absorbent paper than on the other face side. CONSTITUTION: A sanitary napkin 10 is provided with a liquid-permeable surface material 21, a liquid-nonpermeable leakproof material 23, and a liquid holding absorber 22 inserted between them. The absorber 22 is provided with the absorbent paper 22A and a high-absorption poylmer 22B, the absorbent paper 22A contains bulky cellulose fibers and hydrophilic fine fibers or hydrophilic fine powder, and the abundance ratio of the hydrophilic fine fibers or hydrophilic fine powder is set higher on one face side of the absorbent paper than on the other face side. The average fiber length of the bulky cellulose fibers is set to 1-20mm, the average fiber length of the hydrophilic fine fibers is set to 0.02-0.5mm, and the average powder grain size of the hydrophilic fine powder is set to 0.02-0.5mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorbent article, and more particularly to a thin absorbent article provided with absorbent paper having excellent liquid absorption and diffusion properties.

[0002]

2. Description of the Related Art Regarding absorbent articles such as disposable diapers, sanitary napkins and pads for incontinence, many techniques aimed at improving the absorbability of body fluids have been proposed and improved. Has been done. And
Most of these improvements were in improving the liquid absorption rate, preventing the liquid from returning from the absorber to the surface material, preventing liquid leakage, and reducing the stickiness of the absorbent article to the body.

For example, regarding the material of the absorbent body, instead of using hydrophilic absorbent paper or pulp which absorbs and holds the liquid in the physical fine space, the liquid is subjected to a physicochemical action, that is, It has been proposed to use a super-absorbent polymer that improves the liquid absorption capacity by absorbing and holding the liquid by ionic osmotic pressure and prevents the liquid from returning after absorbing the liquid. By using a superabsorbent polymer, the liquid absorbency is improved, and at present, most absorbent articles use an absorbent body in which pulp and a superabsorbent polymer are used in combination.

However, even with such an absorbent article, liquid leakage prevention is still insufficient, as suggested by the fact that the first dissatisfaction with the absorbent article is liquid leakage.

That is, the absorption rate of a liquid is limited in a superabsorbent polymer that absorbs and retains the liquid by ionic osmotic pressure. Further, since the superabsorbent polymer cannot absorb the liquid unless it is wet with the liquid, the superabsorbent polymer has to be used in combination with pulp or absorbent paper having a high liquid absorption rate. However, pulp has a problem that when a flexible fluff absorbent layer is formed as an absorber, it locally absorbs liquid, and thus has poor diffusivity for efficiently utilizing the entire absorber.

[0006] Further, while pulp exhibits a certain degree of compression recovery and bending recovery when it is dried, its strength is extremely reduced when it is wet, and it hardly shows those recovery properties. Therefore, when stress is applied to the wet pulp, The pulp is compressed and deformed (hereinafter referred to as “break”), and the liquid absorption space is significantly reduced. As a result, the once absorbed liquid easily returns to the body side due to the twist, which causes stickiness and liquid leakage.

Further, the liquid absorption space is reduced due to this twisting, whereby the movement resistance when the liquid moves to the polymer is increased. As a result, not only the liquid absorption efficiency of the polymer is lowered, but also the re-absorption rate of the entire absorbent body after twisting is significantly reduced, which often causes liquid leakage.

In order to improve the poor diffusibility of these fluff pulps and the reduction of the liquid absorption space due to twisting, a technique for improving the diffusivity and the liquid return property by compressing / densifying the pulp is also used. Have been reported up to. However, these techniques do not solve the essential problem that the strength of pulp becomes extremely low when it gets wet, and conversely, the distance between fibers of pulp becomes too close, so that liquid becomes a polymer. The movement resistance at the time of movement greatly increases, resulting in a disadvantage that the liquid absorption efficiency of the polymer deteriorates. That is, in the absorber made of fluff pulp, the liquid absorbency and the diffusibility were not compatible with each other, and the absorbency / leak prevention property was still insufficient.

On the other hand, most of the above-mentioned absorbent paper is absorbent paper obtained by wet-making natural pulp. However, the absorbent paper manufactured by such a method has a strong interfacial tension between water and pulp due to hydrogen bond during pulp dehydration and drying during dehydration / wet pressure / drying process during papermaking. Works. Due to this tightening force, the pulp fibers are tightly tightened. As a result, the absorbent paper obtained by wet papermaking of pulp fibers not only has a very slow liquid absorption / permeation, but also the pulp fiber space that substantially absorbs the liquid is extremely reduced.

There has also been attempted a method of improving the bulkiness of the absorbent paper by creping or embossing the absorbent paper. However, in such a method, only the apparent thickness of the absorbent paper is improved, the liquid absorption space composed of pulp fibers is hardly increased, and the liquid absorption / permeability is not improved.

Also, an absorbent paper mainly composed of bulky cellulose fibers has been proposed. Since such an absorbent paper has a large fiber-to-fiber distance, it is excellent in the liquid absorption rate and the liquid transmission rate, but is inferior in the liquid diffusivity. Therefore, the liquid stays on the surface of the absorbent paper, and the surface of the absorbent paper lacks the slat feel. Furthermore, if pressure is applied while absorbing the liquid, liquid return easily occurs. On the other hand, absorbent paper mainly composed of softwood pulp or hardwood pulp having a small fiber diameter has also been proposed. Since such absorbent paper has a high density, it is excellent in liquid absorbability and liquid diffusibility due to the capillary phenomenon, but it is inferior in liquid permeability, so that the liquid remains retained on the surface of the absorbent paper and the salat of the absorbent paper surface is Lack of feeling. As described above, it is difficult to develop the liquid absorbing and transmitting properties and the liquid diffusing property with only one sheet of absorbent paper.

Attempts have also been made to manufacture bulky absorbent paper by using a dry method such as the air ray method for manufacturing the absorbent paper.
That is, bulky absorbent paper is manufactured by depositing pulp in bulk and binding it with an appropriate binder. According to this method, it is possible to obtain absorbent paper having a very low density when dried, a large distance between pulp fibers, and a large liquid absorption space. Such an absorbent paper has a large liquid absorbing space even when absorbing liquid, but has a drawback that its diffusivity is very poor. Further, when the absorbent paper is under pressure while being wet with a liquid, there is a problem in that, like the fluff pulp, twisting / sagging occurs.

Cellulose non-woven fabrics such as rayon spunbond are also used as absorbent paper. Since the non-woven fabric is composed of single fibers, the function of the non-woven fabric absorbent paper is such that the liquid diffusivity and the liquid absorptivity are in a contradictory relationship. That is, the diffusibility of the liquid tends to be improved by decreasing the fiber diameter of the single fiber, but this also reduces the distance between the fibers, and therefore the liquid absorption and permeability is deteriorated. On the contrary, when the fiber diameter of the single fiber is increased, the liquid absorption and permeability are improved, but the liquid diffusibility is deteriorated. As described above, the absorbent paper using the non-woven fabric cannot satisfy both the liquid diffusibility and the liquid absorption and permeability.

Japanese Patent Laid-Open No. 4-89053 discloses a highly absorbent and ultrathin structure in which an absorbent body is formed by combining various absorbent papers having different liquid absorption and liquid diffusivity and a highly absorbent polymer. Absorbent articles are disclosed. However, in such absorbent articles, temporary absorption / permeation / permeation /
Since each function of the absorbent article of diffusion / holding is assigned to each of the constituent members such as the absorbent paper and the superabsorbent polymer forming the absorbent body, there is a drawback that the structure of the absorbent body becomes complicated, and the cost is reduced. There is a problem called up.

Accordingly, an object of the present invention is to provide an absorbent article comprising an absorbent paper having a large liquid absorbing space, a high liquid absorbing and transmitting property, and a high liquid diffusing property.

It is another object of the present invention to provide an absorbent article which has a high liquid absorbency, a small liquid leakage, an ultrathin and comfortable wearing feeling.

[0017]

Means for Solving the Problems As a result of earnest studies, the inventors of the present invention have found that an absorbent paper used as an absorbent body of an absorbent article has a combination of specific fibers and an absorption ratio provided with a gradient. It has been found that paper has both properties of liquid diffusivity and liquid absorption and permeability.

The present invention has been made based on the above findings, and has a liquid permeable surface material, a liquid impermeable leak preventive material, and a liquid retaining property interposed between the surface material and the leak preventive material. In an absorbent article comprising an absorbent body, the absorbent body comprises absorbent paper and a superabsorbent polymer, and the absorbent paper comprises bulky cellulose fibers and hydrophilic fine fibers or hydrophilic fibers. The fine particles of hydrophilicity or the fine particles of hydrophilicity include a fine powder of, and the presence ratio on one surface side of the absorbent paper is higher than the presence ratio on the other surface side of the absorbent paper. The average fiber length of the cellulose fibers is 1 to 20 mm, and the average fiber length of the hydrophilic fine fibers is 0.02 to
The above object was achieved by providing an absorbent article characterized in that the hydrophilic fine powder has an average powder particle size of 0.02 to 0.5 mm. It is a thing.

[0019]

The absorbent paper used in the absorbent article of the present invention contains bulky cellulose fibers and hydrophilic fine fibers or hydrophilic fine powders, as described above. The bulky cellulose fiber forms a bulky network structure in the absorbent paper. On the other hand, in the hydrophilic fine fibers or hydrophilic fine powder, the abundance ratio on one surface side of the absorbent paper is higher than the abundance ratio on the other surface side. As a result, the surface side where the hydrophilic fine fibers or the hydrophilic fine powder is present in a low proportion is excellent in the liquid absorption rate and the local liquid absorbency, and at the same time, the liquid permeation is high. On the other hand, the surface side having a high proportion of the hydrophilic fine fibers or the hydrophilic fine powder, because the hydrophilic fine fibers or the hydrophilic fine powder has a high surface area, Excellent liquid diffusivity. Therefore, it is possible to quickly diffuse the liquid that has permeated the surface side where the hydrophilic fine fibers or the hydrophilic fine powder is present in a low proportion. As described above, the absorbent paper used in the absorbent article of the present invention has both a property of absorbing and transmitting liquid and a property of diffusing liquid, despite having a single structure. As described above, since the absorbent paper has a liquid absorption / diffusion gradient in its single structure, the liquid absorption speed is high, and the liquid spot absorptivity and the liquid permeability and diffusivity are improved. Excellent, resulting in a very high surface slat feel. Therefore, the absorbent article of the present invention configured by using the absorbent paper, by the function of the absorbent paper, of the liquid from the liquid-permeable surface material to the superabsorbent polymer present in the liquid-retaining absorber The flow can be idealized, it has extremely high absorbency, there is little liquid leakage, and it is extremely thin, which makes it comfortable to wear.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION First, an absorbent paper used in the absorbent article of the present invention will be described in detail with reference to the drawings together with a preferable manufacturing method thereof. Here, FIG. 1 is a schematic view showing a cross section in the thickness direction of absorbent paper used in the absorbent article of the present invention, and FIG.
It is a schematic diagram which shows the state of diffusion.

As shown in FIG. 1, the absorbent paper 11 contains bulky cellulose fibers 12 and hydrophilic fine fibers 13 or hydrophilic fine powders 13, and the hydrophilic fine fibers 1 are
3 or hydrophilic fine powder 13 has a higher abundance ratio on one surface side of the absorbent paper 11 than the abundance ratio on the other surface side, and the average fiber length of the bulky cellulose fibers 12 is 1 to 1. 20 mm, the hydrophilic fine fiber 13
Has an average fiber length of 0.02 to 0.5 mm, and the hydrophilic fine powder 13 has an average powder particle diameter of 0.02 to 0.5 mm.
It is characterized by being 0.5 mm.

As shown in FIG. 1, the hydrophilic fine fibers 1 contained in the absorbent paper 11 used in the absorbent article of the present invention.
3 or the hydrophilic fine powder 13 has a gradient in the distribution in the thickness direction of the absorbent paper 11. That is,
In the thickness direction of the absorbent paper 11, the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 is present in the absorbent paper 11 on one surface side more than the other surface side. Is also getting higher. In the following description, of the surfaces of the absorbent paper 11, the surface on which the ratio of the hydrophilic fine fibers 13 or the hydrophilic fine powders 13 is lower is referred to as “surface”, and the hydrophilic fine The surface on which the abundance of the fibers 13 or the hydrophilic fine powder 13 is high is referred to as "back surface".

As shown in FIG. 2, the bulky cellulose fibers 12 are mainly contained in the absorbent paper 11 used in the absorbent article of the present invention from the "surface" to the vicinity of the "surface". , Has a function of quickly absorbing a liquid (indicated by an arrow in FIG. 2) and quickly transmitting the liquid to the “back surface”. That is, this region mainly functions as an "absorption-permeation layer" for the liquid. On the other hand, from "back side" to "back side"
Since the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 is mainly used in the vicinity, it has a function of quickly diffusing the liquid that has permeated from the “surface”. That is, this region primarily functions as a "diffusion layer" for liquids. As described above, the absorbent paper 11 used for the absorbent article of the present invention is characterized by having both the absorption and transmission layer and the diffusion layer in a single structure, and as a result, the liquid absorbency is high, Moreover, after absorbing the liquid, the surface is extremely dry (feeling of slat).

As mentioned above, the "front side" and the "back side"
There is a large difference in the diffusibility of the liquid between. That is, on the "back surface" side (diffusion layer) where the hydrophilic fine fibers or the hydrophilic fine powder is the main component, the liquid diffuses quickly. On the other hand, on the "surface" side (absorption / permeation layer) where the bulky cellulose fiber is the main component, the absorption and transmission of liquid is rapid, but the diffusion of liquid is not so rapid. That is, the absorbent paper used in the absorbent article of the present invention has a diffusion gradient with respect to the diffusion of the liquid in the thickness direction. Therefore, for example, if the diffusion area when the absorbent paper absorbs 1 g of physiological saline is adopted as a measure of the diffusibility of the liquid, the diffusion area on the "back surface" side is the diffusion area on the "front surface" side. Will be larger than. In the present invention, the ratio of the diffusion area on the “rear surface” side to the diffusion area on the “front surface” side of the absorbent paper is preferably 1.2 or more, and more preferably 1.
5 to 20, particularly preferably 2 to 20. The details of the method for measuring the diffusion area will be described later.

The abundance ratio of the hydrophilic fine fibers or the hydrophilic fine powder in the absorbent paper used for the absorbent article of the present invention gradually increases from the "front surface" to the "back surface". However, it may increase stepwise with a certain thickness as a boundary.

On the other hand, the bulky cellulosic fibers may be present uniformly in the thickness direction of the absorbent paper, but more preferably on the "front surface" side rather than the "back surface" side of the absorbent paper. The existence ratio is higher. That is, it is preferable that the abundance ratio of the bulky cellulose fibers has a gradient in the thickness direction of the absorbent paper.
The existence ratio may be gradually increased from the “rear surface” to the “front surface”, or may be increased stepwise with a certain thickness as a boundary.

More specifically, the hydrophilic fine fibers or the hydrophilic fine powders are contained in a total amount in a depth of about 1/3 in the thickness direction from the "back surface" side of the absorbent paper. Preferably about 5 to about 70% by weight, more preferably about 10% by weight.
About 50% by weight is present, and the diffusion layer mainly composed of the hydrophilic fine fibers or the hydrophilic fine powder is formed. On the other hand, about 2 from the “front” side of the absorbent paper in the thickness direction.
At a depth of up to / 3, the bulky cellulose fibers are preferably present in an amount of about 60 to about 100% by weight, more preferably about 70 to about 97% by weight, based on the total weight of the bulky cellulose fibers. The absorptive and transmissive layer which is the main component is formed.

As described above, the distribution of the bulky cellulose fibers and the hydrophilic fine fibers or the hydrophilic fine powder may be gradually increased in the thickness direction of the absorbent paper. The thickness may increase stepwise. And, in the thickness direction of the absorbent paper, both the bulky cellulosic fibers and the hydrophilic fine fibers or the hydrophilic fine powder have a gradient in the distribution thereof. Particularly preferred implementation of the absorbent paper. In the form, the absorption and permeability of the liquid and the diffusibility of the liquid can be more remarkably exhibited.

As described above, the absorbent paper used in the absorbent article of the present invention mainly has a "front surface" side for absorbing and transmitting liquid and a "rear surface" side for diffusing liquid. Therefore, when using the absorbent article of the present invention, it is preferable that the "front surface" side of the absorbent paper is the side that comes into contact with the liquid first.

In the absorbent paper used in the absorbent article of the present invention, the compounding ratio of the bulky cellulose fiber and the hydrophilic fine fiber or the hydrophilic fine powder is not particularly limited, but is not limited to the above. The bulky cellulose fiber is preferably contained in an amount of 50 to 97 parts by weight, and more preferably 70 to 95 parts by weight, based on 100 parts by weight of the absorbent paper. The bulky cellulose fiber content is 5
If the amount is less than 0 parts by weight, the bulky network structure may be insufficient and an absorbent paper having both permeability and diffusion may not be obtained, and the blending ratio of the bulky cellulose fibers is 97.
When the amount is more than parts by weight, the blending ratio of the hydrophilic fine fibers or the hydrophilic fine powder becomes low and the diffusibility becomes insufficient, so that the above range is preferable.

The hydrophilic fine fiber or the hydrophilic fine powder is 3 parts by weight based on 100 parts by weight of the absorbent paper.
It is preferably contained in an amount of from 50 to 50 parts by weight, more preferably from 5 to 30 parts by weight. If the blending ratio of the hydrophilic fine fibers or the hydrophilic fine powder is less than 3 parts by weight, the diffusivity becomes insufficient, and the blending ratio of the hydrophilic fine fibers or the hydrophilic fine powder is insufficient. When it exceeds 50 parts by weight, the compounding ratio of the hydrophilic fine fibers or the hydrophilic fine powder on the "surface" side increases and the permeability becomes insufficient. Therefore, the above range is preferable.

If desired, the absorbent paper used in the absorbent article of the present invention may contain hot-melt adhesive fibers which are melted by heating and adhered to each other. By adding such a heat-meltable adhesive fiber, the structural stability of the absorbent paper when wet can be maintained.

The heat-meltable adhesive fiber is used in the absorbent paper 10 described above.
It is preferable to add 2 to 30 parts by weight, more preferably 3 to 20 parts by weight, based on 0 parts by weight. If the added amount is less than 2 parts by weight, the strength when absorbing a liquid is insufficient, or the bulky cellulose fiber and the hydrophilic fine fiber or the hydrophilic fine fiber in the absorbent paper are used. The mixed state with the powder may change and 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 absorbent paper may be lowered, and the liquid absorption rate and the liquid diffusing ability may become insufficient, so the above range is preferable.

Other optional ingredients that can be added to the absorbent paper used in the absorbent article of the present invention include, for example, other pulps such as softwood pulp, hardwood pulp, straw pulp and dialdehyde as a strong auxiliary agent. Examples thereof include starch, sponge and carboxymethyl cellulose. These components can be added in an amount of 0 to 20 parts by weight based on 100 parts by weight of the absorbent paper.

[0035] No particular limitation is imposed on the basis weight of the absorbent sheet used in the absorbent article of the present invention, is preferably from 10 to 200 g / m ^2, and still more preferably from 20 to 150 g / m ^2. If the grammage is less than 10 g / m ² , the absorbent paper may be too thin to exhibit the functions of transmission and diffusion. If the grammage exceeds 200 g / m ² , the absorbent paper may be adversely affected. May become too thick and smooth transmission of liquid such as permeation and diffusion may not occur easily, so the above range is preferable.

The thickness of the absorbent paper used in the absorbent article of the present invention is not particularly limited, but the thickness under a load of 2.5 g / m ² is preferably 0.2 to ² mm, and 0.2 ~ 1m
More preferably m. If the thickness is less than 0.2 mm, the absorbent paper may be too thin to exhibit the functions of transmission and diffusion. If the thickness exceeds 2 mm, smooth transmission of liquid, transmission and diffusion, may occur. Since it may be difficult to occur, the above range is preferable.

In a preferred embodiment of the absorbent paper used in the absorbent article of the present invention, 50 to 97 parts by weight of the bulky cellulose fiber and 100% by weight of the absorbent paper, and the hydrophilic fine particles are used. 3 to 50 parts by weight of the fiber or the hydrophilic fine powder is included.

In a particularly preferred embodiment of the absorbent paper used in the absorbent article of the present invention, the bulky cellulose fiber is contained in an amount of 70 to 70 parts by weight based on 100 parts by weight of the absorbent paper.
95 parts by weight, 5 to 30 parts by weight of the hydrophilic fine fibers or the hydrophilic fine powder, and 2 to 30 parts by weight of the hot-melt adhesive fibers; and the basis weight of the absorbent paper is 10 to 10 parts by weight.
It is 200 g / m ² .

The absorbent paper is preferably manufactured by the method described below. That is, as shown in FIG. 3, the absorbent paper includes the bulky cellulose fibers 12 having an average fiber length of 1 to 20 mm and the hydrophilic fine fibers 13 having an average fiber length of 0.02 to 0.5 mm. Alternatively, the average powder particle size is 0.
A step of dispersing the hydrophilic fine powder 13 having a thickness of 02 to 0.5 mm in water to form a slurry 14, and spraying the slurry 14 on a papermaking wire 15 to form a paper layer on the papermaking wire 15. It is preferably manufactured by a method including a step of forming 16 and a step of dehydrating and drying the paper layer 16.

Thus, the absorbent paper used in the absorbent article of the present invention is preferably produced by the wet papermaking method. The wet paper machine is not particularly limited, and for example, a round net paper machine, a former paper machine, and a Fourdrinier paper machine can be used.

The papermaking method will be described in more detail with reference to FIG. 4, which is an enlarged view of the portion (a) of FIG. When the slurry 14 is sprinkled on the papermaking wire 15, the water in the slurry 14 is removed through the papermaking wire 15 and at the same time the paper layer 16 is formed on the papermaking wire 15.
Is formed. In the paper layer 16, the bulky cellulose fibers 12 form a bulky network structure 17 in the thickness direction as shown in FIG. On the other hand, since the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 in the slurry 14 is finer than the bulky cellulose fibers 12, it passes through the network structure 17 together with water, and Deposit on the papermaking wire 15. As a result, the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 has a gradient in the distribution in the thickness direction of the absorbent paper 11. That is, as shown in FIG. 4, of the surface of the paper layer 16, the papermaking wire 1
The hydrophilic fine fibers 1 on the side in contact with 5
3 or the existence ratio of the hydrophilic fine powder 13 is higher than the existence ratio on the other surface.

As described above, in the preferred method for producing the absorbent paper, the bulky cellulose fiber 12, the hydrophilic fine fiber 13 or the hydrophilic fine powder 13 is used.
By utilizing the difference in the fiber length and the fiber diameter from the above, the existence ratio of the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 in the thickness direction of the absorbent paper is provided with a gradient.

The concentration of the bulky cellulose fibers 12 in the slurry is preferably 0.02 to 1% by weight, more preferably 0.03 to 0.7% by weight, based on the total amount of the slurry. Is. If the concentration of the bulky cellulose fibers 12 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 loss. If the concentration of the bulky cellulose fiber 12 exceeds 1% by weight, the dispersibility of the fiber deteriorates,
Since unevenness of the paper layer may occur, the above range is preferable.

On the other hand, the concentration of the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 in the slurry is preferably 0.00 based on the total amount of the slurry.
2 to 0.5% by weight, and more preferably 0.003
Is about 0.3% by weight. The concentration of the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 is 0.002% by weight.
If the content is less than the above, the desired diffusivity may not be obtained, and if the concentration of the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 exceeds 0.5% by weight, the "surface" is obtained. The hydrophilic fine fibers 13 or the hydrophilic fine powder 13 may be present on the side as well, and the desired diffusion gradient may not be obtained, so the above range is preferable.

The concentration of the heat-meltable adhesive fiber optionally used in the absorbent paper is preferably 0.001 to 0.3% by weight in the slurry.
It is more preferable to set it to 0.002 to 0.2% by weight.
If the above concentration is less than 0.001% by weight, the purpose of keeping the structure of the absorbent paper stable may not be achieved,
If the above concentration exceeds 0.3% by weight, the hydrophilicity of the entire absorbent paper may decrease, so the above range is preferred.

As described above, in the preferred method for producing the absorbent paper used in the absorbent article of the present invention, when the slurry 14 is sprinkled on the papermaking wire 15, the bulkiness of the bulky cellulose fiber 12 is increased. A fine network structure 17 is formed, and the hydrophilic fine fibers 13 or the hydrophilic fine powders 13 pass through the space in the bulky network structure 17 to make the papermaking wire 15.
Deposit on top. For this purpose, it is important to make the average fiber length of the hydrophilic fine fibers 13 or the average powder particle diameter of the hydrophilic fine powder 13 larger than the mesh of the papermaking wire 15. The hydrophilic fine fiber 1
When the average fiber length of 3 or the average particle diameter of the hydrophilic fine powder 13 is smaller than the mesh 15 of the papermaking wire, the hydrophilic fine fiber 13 or the hydrophilic fine powder 13 is Since it passes through the papermaking wire 15, it becomes impossible to provide a gradient in the abundance ratio of the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 in the thickness direction of the absorbent paper, which is not preferable. .
If the mesh of the papermaking wire 15 is too small, the hydrophilic fine fibers 13 or the hydrophilic fine powder 13 will be clogged on the papermaking wire 15, which is not preferable. Therefore, the opening diameter of the papermaking wire is 22 to 300 μm (58
0 to 50 mesh), preferably 45 to 25
It is more preferably 0 μm (330 to 60 mesh) (based on new JIS (1987)).

The absorbent used in the absorbent article of the present invention described above.
According to a preferable method for manufacturing a paper receiving paper, the thickness of the absorbent paper
In view of the above, the hydrophilic fine fibers 13 or the hydrophilic
It is particularly easy to provide a gradient in the distribution of the fine powder 13 of
it can. The degree of such a gradient depends on the papermaking wire 15 described above.
Speed for dehydrating the paper layer 16 formed on the
Speed). That is, the papermaking speed and the basis weight of the absorbent paper
Although it depends on the above, if the dehydration speed is low, the degree of the gradient will be small.
As a result, the odor in the thickness direction of the absorbent paper
The hydrophilic fine fibers 13 or the hydrophilic fine powder
The body 13 may be distributed almost uniformly. on the other hand,
The higher the dehydration rate, the greater the degree of the gradient.
However, a large amount of energy is required to increase the speed of dehydration.
It takes a ghee. In consideration of these, the present invention
The above dehydration rate is 2 ml / [cm ²・ Sec] or more
Preferably 3 to 30 ml / [cm²・ Sec]
It is even more preferable. For dehydration, for example, normal
Using the suction box used in wet paper machines
Can be

According to the above-mentioned method, it is possible to manufacture the absorbent paper which can exhibit the liquid permeability and the liquid diffusivity by one papermaking process, and the papermaking process can be simplified. .

Although the method of manufacturing the absorbent paper used in the absorbent article of the present invention has been described based on its preferred embodiment, the method of manufacturing the absorbent paper is not limited to the above embodiment, and other embodiments are possible. The above-mentioned absorbent paper can be produced by a form such as a dry papermaking method.

As another manufacturing method, a fiber web is formed from bulky cellulose fibers, and then hydrophilic fine fibers or hydrophilic fine powder is sprinkled from the web, and then dried and integrated. By doing so, an absorbent paper having a bulky cellulose fiber layer on one side and a hydrophilic fine fiber or hydrophilic fine powder-based layer on the other side can be obtained. According to this method, it is possible to manufacture an absorbent paper in which the abundance ratio of the bulky cellulose fiber and the hydrophilic fine fiber or the hydrophilic fine powder in the thickness direction changes stepwise.

Next, the bulky cellulose fibers used in the absorbent paper will be described in detail.

In the absorbent paper, it is preferable to form a network structure of the bulky cellulose fibers. Such a network structure is a particularly preferred structure because it quickly absorbs liquid and allows liquid to quickly permeate to the "back" side. For this purpose, the bulky cellulose fibers 13 need to have an average fiber length of 1 to 20 mm, and a preferable average fiber length is 2 to 10 mm.
And a more preferable average fiber length is 2 to 5 mm. If the average fiber length is less than 1 mm, the above bulky network structure cannot be formed, and the hydrophilic fine fibers or the hydrophilic fine powder may pass through between the bulky network structures. Can not. When the average fiber length exceeds 20 mm, dispersibility in water deteriorates and a uniform network structure cannot be formed.

As the bulky cellulose fiber, any cellulose fiber may be used as long as it is bulky.
As the cellulose fiber, for example, natural cellulose such as wood pulp or cotton, regenerated cellulose such as rayon or cupra can be used. From the viewpoint of cost, it is preferable to use wood pulp, and particularly softwood kraft pulp is preferably used. These cellulose fibers may be used alone or in combination of two or more.

As a preferable example of the bulky cellulose fiber, there is a crosslinked cellulose fiber obtained by crosslinking the inside and / or the inside of the cellulose fiber. Such crosslinked cellulose fibers are preferable because they can maintain a bulky structure even in a wet state. A more preferable bulky cellulose fiber is
A crosslinked pulp, and a more preferable bulky cellulose fiber is a crosslinked pulp obtained by crosslinking a pulp having an average fiber length of 2 to 5 mm.

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 cross-linking agents include N-methylol compounds such as dimethylol ethylene urea and dimethylol dihydroxy ethylene urea; polycarboxylic acids such as citric acid, tricarballylic acid and butane tetracarboxylic acid; polyols such as dimethyl hydroxyethylene urea. ;
Examples thereof include cross-linking agents for polyglycidyl ether compounds. In particular, a cross-linking agent of a polycarboxylic acid or a polyglycidyl ether-based compound that does not generate formalin or the like which is harmful to the human body during cross-linking is preferable.

The amount of the cross-linking agent used is preferably 0.2 to 20 parts by weight with respect to 100 parts by weight of the cellulose fibers. If the amount used is less than 0.2 parts by weight, the cross-linking density of the cellulose fibers is low, so the elastic modulus may decrease significantly when wet, and if the amount used exceeds 20 parts by weight, the cellulose fibers will be Since the cellulose fiber may become too rigid and become brittle when stressed, the above range is preferable.

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

The bulky cellulose fiber preferably has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Such cellulose fibers are preferable because the cellulose fibers are accumulated in a bulky state and the bulky network structure is easily formed.

In the present invention, the term "fiber roughness" means a fiber having a non-uniform thickness, such as wood pulp.
It is used as a scale representing the thickness of the fiber, and for example, a fiber roughness meter (F manufactured by KAJANNI ELECTRONICS LTD.
S-200).

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, more preferably a fiber roughness of 0.3 to
2 mg / m, more preferable fiber roughness is 0.32-1
It is mg / m.

Examples of cellulose fibers having a fiber roughness of 0.3 mg / m 2 or more include softwood kraft pulp [Federal Pa].
"ALBACEL" (brand name) made by per Board Co., and PTI
"INDORAYON" (product name) made by ntiIndorayon Utama]
Etc.

The bulky cellulose fiber preferably has a roundness of the fiber cross section of 0.5 to 1. Cellulose fibers having a roundness of the fiber cross section of 0.5 to 1
It is preferable because the liquid has a low resistance to movement and a high liquid permeation rate. More preferably, the roundness is 0.55 to 1. The method for measuring the roundness of the fiber cross section will be described later.

As described above, in the present invention, it is preferable to use wood pulp as the cellulose fiber,
Generally, the cross section of wood pulp is flat due to the delignification treatment, and most of the roundness thereof is less than 0.5. In order to make the roundness of such a wood pulp 0.5 or more, for example, the wood pulp having an average fiber length of 1 to 20 mm may be mercerized to swell the cross section of the wood pulp.

Thus, the roundness of the fiber cross section is 0.5 to
As the cellulose fiber of 1, mercerized pulp having a circularity of 0.5 to 1 obtained by mercerizing wood pulp is preferable. Examples of commercially available mercerized pulps that can be used in the present invention include ITT Rayoni
er Inc.'s "FILTRANIER" (product name) and the company's "PO"
ROSANIER ”(brand name) and the like.

In the present invention, it is also preferable to use a crosslinked mercerized pulp obtained by crosslinking the above mercerized pulp by the above method.

In the present invention, the average fiber length is 2
Cellulose fibers (pulp) having a fiber roughness of 0.3 mm / m or more and a roundness of the fiber cross section of 0.5 to 1 are also preferable.

More preferable bulky cellulose fibers have an average fiber length of 2 to 5 mm and a fiber roughness of 0.3 mg.
/ M or more and the roundness of the cross section of the fiber is 0.5 to 1, which is crosslinked by the above-mentioned method.

Particularly preferred bulky cellulose fibers have an average fiber length of 2 to 5 mm and a fiber roughness of 0.3.
A pulp having a mg / m or more is mercerized to have a circularity of a fiber cross section of 0.5 to 1, and then crosslinked by the above-mentioned method.

Next, the hydrophilic fine fibers and the hydrophilic fine powder used in the absorbent paper will be described in detail.

The surface of the hydrophilic fine fibers is hydrophilic, and the average fiber length thereof is 0.02 to 0.5 mm, preferably 0.03 to 0.3 mm. On the other hand, the hydrophilic fine powder has a hydrophilic surface and an average powder particle size of 0.02 to 0.5 mm, preferably 0.03 to 0.3.
mm. The average fiber length of the hydrophilic fine fibers is 0.0
When the average fine particle diameter of the hydrophilic fine powder is less than 2 mm or less than 0.02 mm, the hydrophilic fine fiber or the hydrophilic fine powder is a papermaking wire in the above-described preferred method for producing absorbent paper. And the hydrophilic fine fibers or the hydrophilic fine powder cannot be deposited on the papermaking wire. Further, when the average fiber length of the hydrophilic fine fibers exceeds 0.5 mm or the average particle diameter of the hydrophilic fine powder exceeds 0.5 mm, in the above-described preferred method for producing absorbent paper, The hydrophilic fine fibers or the hydrophilic fine powder cannot pass through the network structure formed by the bulky cellulose fibers and cannot be deposited on the papermaking wire. In the present invention, since the hydrophilic fine fibers and the hydrophilic fine powder are not generally clearly distinguished and used, both expressions are used for convenience.

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

As the hydrophilic fine fibers and the hydrophilic fine powder, commercially available products can be used.
For example, pulp floc (trade name) manufactured by Sanyo Kokusaku Pulp Co., Ltd., which is obtained by beating wood pulp such as softwood pulp and hardwood pulp, then mechanically crushing and then separating with a sieve of 0.5 mm or less, etc. To be As another example, cellulose fine fibers (powder) obtained by mechanically crushing cellulose fibers such as wood pulp, then hydrolyzing with acid, and then mechanically crushing (manufactured by Sanyo Kokusaku Pulp Co., Ltd.) K
C Flock (trade name) and Avicel (trade name) manufactured by Asahi Kasei Co., Ltd.]. In addition, as commercially available inorganic fine fibers, hydrous magnesium silicate fibers [ATE PLUS ML-30 (trade name) manufactured by Mizusawa Chemical Industry Co., Ltd.]
Etc. Among these commercially available products, cellulose fine fibers and cellulose fine powder obtained by pulverizing pulp into fine particles can be obtained at a lower cost and can be preferably used.

Next, the above-mentioned heat-meltable adhesive fiber which is optionally used for the above-mentioned absorbent paper will be described in detail.

Examples of the heat-meltable adhesive fibers include polyolefin fibers such as polyethylene, polypropylene and polyvinyl alcohol, polyester fibers, polyethylene-polypropylene composite fibers, polyethylene-polyester composite fibers, low melting point polyester-polyester composite fibers, Examples thereof include polyvinyl alcohol-polypropylene composite fibers having a hydrophilic fiber surface, and polyvinyl alcohol-polyester composite fibers.
When the conjugate fiber is used, both the core-sheath type conjugate fiber and the side-by-side type conjugate fiber can be used. These heat-meltable adhesive fibers may be used alone or in combination of two or more.
Examples of the heat-meltable adhesive fiber preferably used in the present invention include polyvinyl alcohol fiber soluble in hot water and core-sheath type polyester fiber.

The above-mentioned heat-meltable adhesive fiber has an average fiber length of preferably 2 to 60 mm, particularly preferably 3 to 20 mm. When the average fiber length is less than 2 mm, the strength of the absorbent paper becomes insufficient, and when the average fiber length exceeds 60 mm, the strength cannot be evenly dispersed in water and the strength becomes uneven. Therefore, the above range is preferable. The heat-meltable adhesive fiber has a fiber diameter of preferably 0.1 to 3 denier, particularly preferably 0.5 to 2 denier. If the fiber diameter is less than 0.1 denier, the strength of the fibrous body will be insufficient and the strength of the entire absorbent paper cannot be expressed. If the fiber diameter exceeds 3 denier, the strength of the absorbent paper will decrease due to the decrease in the number of bonded fibers. Since it becomes insufficient, it is preferable to set it in the above range.

Next, the absorbent article of the present invention will be described with reference to FIGS. 5 and 6.

Here, FIG. 5 is a schematic view showing a cross section in the width direction of a sanitary napkin as one embodiment of the absorbent article of the present invention. FIG. 6 is a schematic view (corresponding to FIG. 5) showing a cross section in the width direction of a sanitary napkin as another embodiment of the absorbent article of the present invention.

The sanitary napkin 10 as one embodiment of the absorbent article of the present invention shown in FIG. 5 has a liquid-permeable surface material 2
1. A liquid impermeable leak preventer 23 and a liquid retaining absorbent 22 interposed between the surface member and the leak preventer.

More specifically, the sanitary napkin 10 described above.
Is substantially vertically long, and when the sanitary napkin 10 is worn, the surface material 21 is located on the side in contact with the skin, and the leak preventer 23 is located on the side in contact with the underwear. The absorber 22 is interposed between the surface material 21 and the leak preventer 23.

Further, as shown in FIG. 5, the absorbent body 22 has the lower surface, the entire side surface and the peripheral edge portion of the upper surface, the leakage preventing material 2 being provided.
It is covered by 3. Furthermore, the entire surface of the combination of the absorber 22 and the leak preventer 23 is the surface material 2 described above.
It is covered by 1. As a result, the absorber 22
The central portion of the upper surface of is directly covered with the surface material 21. Therefore, the liquid directly permeates the absorber 22 through the surface material 21.

On the side of the surface material 21 that does not come into contact with the skin, three adhesive portions 24 are formed in a stripe shape in the longitudinal direction. The adhesive section 24 is protected by a release paper 25. In FIG. 5, reference numeral 26 is an adhesive for fixing the surface material 21, the absorber 22, and the leak preventer 23 to each other.

The surface material 21 is not particularly limited as long as it allows liquid to pass through to the absorbent body 22, but a material having a feeling close to that of underwear is preferable. Examples of such a surface material include, for example, woven fabric, non-woven fabric, and porous film of thermoplastic resin. In particular, an apertured film made of polyolefin such as low density polyethylene can be preferably used.

The apertured film can be produced, for example, by the following method. That is, a polyolefin such as low-density polyethylene is melted and extruded from a T die to form a film on the spiral braided wire net 31 made of the wire rod 31a shown in FIGS. 7A and 7B. Then, by aspirating such a film, FIG.
The apertured film 42 having the apertures 44 shown in (A) is obtained. As shown in FIGS. 8 (B) and 8 (C), the perforated film 42 has a large number of tops 45 each having a convex curved surface.
And a large number of apertures 44 located between the tops 45.

The leak preventer 23 is not particularly limited as long as it is liquid impermeable, but it is particularly preferable that the leak preventer 23 has moisture permeability and has a feeling close to that of underwear. The liquid impermeable leak preventer having moisture permeability is, for example, a thermoplastic resin to which a filler of an inorganic compound or an organic compound is added, is melt-extruded from a T die or a circular die to form a film, and then, It can be obtained by uniaxially or biaxially stretching the film.

As shown in FIG. 5, the absorbent body 22 of the absorbent article of the present invention comprises at least the absorbent paper 22A and the super absorbent polymer 22B. Since the absorbent body 22 is extremely thin, a comfortable wearing feeling can be obtained, and furthermore, the absorbent body 22 is highly absorbent and liquid leakage does not easily occur.

More specifically, the above superabsorbent polymer 22
B is wrapped inside the absorbent paper 22A, and the superabsorbent polymer 22B is sandwiched between the absorbent paper 22A. In this case, the super absorbent polymer 22B
It is preferable to sandwich the super absorbent polymer 22B between the absorbent papers 22A so that the sheet comes into contact with the "back surface" of the absorbent paper 22A. With such a configuration, the liquid that has passed through the surface material 21 is quickly absorbed and transmitted by the “front surface” of the absorbent paper 22A, and reaches the “rear surface” of the absorbent paper 22A more smoothly. The liquid that has reached the “back surface” of the absorbent paper 22A is diffused throughout the absorbent paper 22A and then fixed to the superabsorbent polymer 22B.

As described above, in the absorbent article of the present invention, absorption / permeation / diffusion / holding of liquid is carried out very smoothly. As a result, the absorbent article of the present invention can more reliably immobilize the liquid, and moreover, the surface material 2 described above.
The liquid does not remain on the surface 1 and the liquid does not return to the surface material 21. Further, the absorbent body 22 is a sheet of the absorbent paper 22A.
And consisting only of the above superabsorbent polymer 22B,
The absorbent article of the present invention can be made extremely thin and comfortable to wear.

It is preferable that the superabsorbent polymer 22B is capable of absorbing and retaining 20 times or more of its own weight of liquid and capable of gelling. The super absorbent polymer 22B
The shape is not particularly limited, and for example, a spherical shape, a flaky shape, or a particle shape can be used. Examples of such superabsorbent polymers include starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, crosslinked sodium carboxymethyl cellulose and acrylic acid (salt) polymers. Can be mentioned.

Another embodiment of the absorbent article of the present invention will be described with reference to FIG. 6 using a sanitary napkin as an example. The same points as in FIG. 5 will not be described in detail, but FIG.
The detailed description of the above applies as appropriate. Further, in FIG. 6, the same members as those in FIG. 5 are designated by the same reference numerals.

The absorbent body 22 in the sanitary napkin 10 as another embodiment of the absorbent article of the present invention shown in FIG.
Comprises two sheets of the absorbent paper 22A and 22C and the superabsorbent polymer 22B, and the superabsorbent polymer 22B is sandwiched between the absorbent papers 22A and 22C. In this case, the absorbent paper 22A has its "back surface".
Is preferably in contact with the superabsorbent polymer 22B. Further, it is preferable that the "back surface" of the absorbent paper 22C is also in contact with the superabsorbent polymer 22B.
Particularly preferably, the "back surface" of the absorbent paper 22A is in contact with the superabsorbent polymer 22B, and the "back surface" of the absorbent paper 22C is in contact with the superabsorbent polymer 22B. With such a structure, absorption / permeation / diffusion / holding of liquid can be performed extremely smoothly.

Although the absorbent article of the present invention has been described based on its preferred embodiment, the absorbent article of the present invention is not limited to the above embodiment, and other absorbent articles such as a disposable diaper and an incontinence pad can be used. It goes without saying that the same can be applied to a sex article.

[0092]

EXAMPLES Next, the absorbent article of the present invention will be described in more detail with reference to Examples and Comparative Examples.

First, the production of bulky cellulose fibers, hydrophilic fine fibers and hydrophilic fine powders used in Examples and Comparative Examples will be described. In the following description, “%” and “part” represent “% by weight” and “part by weight”, respectively, unless otherwise specified.

Production Example 1 Production of Cellulose Fiber The average fiber length is 2.35 mm and the fiber roughness is 0.36 mg.
/ M, and the roundness of the fiber cross section is 0.80, mercerized pulp ["POROSANI manufactured by ITT RAYONIER INC.
ER-J "(trade name)] 100 g, 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.
AcceleratorX-110 "(trade name)]
The mercerized pulp was dispersed in 00 g to impregnate the crosslinking agent.

Then, the aqueous solution of the crosslinking agent was separated from the mercerized pulp until the amount of the aqueous solution of the crosslinking agent with respect to the mercerized pulp reached 200%, and then heated in an electric dryer at 135 ° C. for 10 minutes. The cellulose in the mercerized pulp was crosslinked to obtain a mercerized crosslinked pulp. This is designated as cellulose fiber (A).

Production Example 2 Production of Cellulose Fiber The average fiber length is 2.56 mm and the fiber roughness is 0.35 mg.
/ M and the roundness of the fiber cross section is 0.28, except for using 100 g of coniferous wood pulp [[INDORAYON] (trade name) manufactured by PT Inti Indorayon Utama]
The same operation as in Production Example 1 was performed to obtain a crosslinked pulp. This is designated as cellulose fiber (B).

Production Example 3 Production of Cellulose Fiber The average fiber length is 2.35 mm and the fiber roughness is 0.36 mg.
/ M, and the roundness of the fiber cross section is 0.80, mercerized pulp ["POROSANI manufactured by ITT RAYONIER INC.
ER-J ”(trade name)] was prepared. This is designated as cellulose fiber (C).

Production Example 4 Production of Cellulose Fibers The average fiber length is 2.38 mm and the fiber roughness is 0.32 mg.
/ M and the roundness of the cross section of the fiber was 0.30, "high bulk additive HBA-S" (trade name) manufactured by Weyerhauser Paper was prepared. This is designated as cellulose fiber (D).

Production Example 5 Production of Cellulose Fiber The average fiber length is 2.56 mm and the fiber roughness is 0.24 mg.
/ M and the roundness of the fiber cross section was 0.34, a softwood kraft pulp [“HARMAC-R” (trade name) manufactured by MacMillan Bloedel Ltd.] was prepared. This is designated as cellulose fiber (E). The cellulose fiber (E) is not crosslinked.

Production Example 6 Production of Cellulose Fiber The average fiber length is 2.56 mm and the fiber roughness is 0.35 mg.
/ M and the roundness of the fiber cross section was 0.28, a softwood clato pulp [“INDORAYON” (trade name) manufactured by PT Inti Indorayon Utama] was prepared. This is called cellulose fiber (F). The cellulose fiber (F) is not crosslinked.

Production Example 7 Production of Cellulose Fiber The average fiber length is 0.75 mm and the fiber roughness is 0.13 mg.
/ M and the roundness of the fiber cross section is 0.35, the hardwood kraft pulp ["BAHIA SU manufactured by BAHIA SUL Co.
L CELULOSE SA "(trade name)] was used to obtain a crosslinked pulp in the same manner as in Production Example 1. This is designated as cellulose fiber (G).

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

<Measurement of Average Fiber Length and Fiber Roughness> It was measured 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 is dried in a vacuum dryer at 100 ° C.
And dried for 1 hour to remove water present in the cellulose fiber.

Accurately weigh approximately 1 g of cellulose fibers to an accuracy of ± 0.1 mg. Next, in order not to damage the cellulose fiber, the cellulose fiber was completely disintegrated in 150 ml of water with a mixer attached to the fiber roughness meter, diluted with water to 5000 ml, and diluted with 50 ml of the diluted solution. Was accurately measured and used as a fiber roughness measuring solution, and the average fiber length and the fiber roughness were determined according to the operation procedure of the fiber roughness meter. As the average fiber length, a value calculated by the following formula based on the above operation was used.

[0105]

[Equation 1]

<Measurement of Roundness of Fiber Cross Section> To measure the roundness of the cellulose fiber cross section, first, the cellulose fiber is sliced perpendicularly to the cross section direction so that the area of the cross section of the cellulose fiber does not change. A cross-section photograph was taken with a microscope, and the cross-section photograph was analyzed by an image analyzer [“Avio EXCEL” (trade name) manufactured by Nippon Avionics Co., Ltd.), and the roundness of the cellulose fiber cross section was obtained using the formula shown below. . The roundness was an average value obtained by measuring 100 cross sections of an arbitrary cellulose fiber.

[0107]

[Equation 2]

[0108]

[Table 1]

[Production Example 8] Production of hydrophilic fine fibers Cellulose fine fibers having an average fiber length of 0.23 mm obtained by acid-hydrolyzing selected pulp, washing with water and drying, and then mechanically pulverizing it [Sanyo Kokusaku "KC Flock W-50" (trade name) manufactured by Pulp Co., Ltd. was prepared. This is referred to as hydrophilic fine fiber (A).

[Production Example 9] Production of hydrophilic fine fibers Cellulose fine fibers having an average fiber length of 0.12 mm obtained by acid-hydrolyzing selected pulp, washing with water and drying, and then mechanically pulverizing it [Sanyo Kokusaku "KC Flock W-100" (trade name) manufactured by Pulp Co., Ltd. was prepared. This is a hydrophilic fine fiber (B).

[Production Example 10] Production of hydrophilic fine fibers Hydrous magnesium silicate fine fibers having an average fiber length of 0.03 mm ["Adeplus ML-3 manufactured by Mizusawa Chemical Industry Co., Ltd.]
0 "(trade name)] was prepared. This is a hydrophilic fine fiber (C).

[Production Example 11] Production of hydrophilic fine fibers Hardwood kraft pulp having an average fiber length of 0.75 mm [BAHIA
"BAHIA SUL CELULOSE SA (trade name)" manufactured by SUL Co. was prepared and used as hydrophilic fine fibers (D).

[Production Example 12] Production of hydrophilic fine fibers Softwood kraft pulp having an average fiber length of 2.34 mm [Skeena
"SKEENA PRIME" (trade name) manufactured by Cellulose Co. was prepared. This is a hydrophilic fine fiber (E).

[Production Example 13]Manufacture of absorbent paper Cellulose fiber (A) concentration is 0.16%, hydrophilic fine
Fine fiber (A) concentration is 0.03% and thickness is 1 denier
Polyvinyl alcohol fiber with an average fiber length of 3 mm
Fibrous bond manufactured by Sansho Co., Ltd.
Name), hereinafter referred to as "PVA" fiber], is 0.0
1% (0.2% as a whole slurry)
These were uniformly dispersed in water to obtain a slurry. This
Rally wire opening diameter 90μm (166 mesh)
Spray on the wire mesh paper wire of
A paper layer was formed. 6 ml using a suction box
/〔cm ²・ Sec] was used to dehydrate this paper layer. Next
Then, after drying the paper layer with a dryer, remove the crepe.
80% / m 2 basis weight²The absorbent paper of this
Absorbent paper is based on 100 parts by weight of absorbent paper
(A) 80 parts, hydrophilic fine fiber (A) 15 parts, top
The PVA fiber contained 5 parts.

[Production Example 14] Production of absorbent paper The concentration of cellulose fibers (B) was 0.16%, the concentration of hydrophilic fine fibers (B) was 0.034%, and the concentration of the PVA fibers was 0. Absorbing paper having a basis weight of 80 g / m ² was obtained by performing the same operations as in Production Example 13 except that these were uniformly dispersed in water to form a slurry so that the amount became 006%.
This absorbent paper contained 80 parts of the cellulose fibers (B), 17 parts of the hydrophilic fine fibers (B), and 3 parts of the PVA fibers based on 100 parts of the absorbent paper.

Production Example 15 Production of Absorbent Paper Cellulose fiber (D) concentration was 0.15%, hydrophilic fine fiber (A) concentration was 0.04%, and thickness was 1.1 denier on average. The concentration of polyethylene terephthalate fiber having a fiber length of 5 mm [heat-melting adhesive fiber, "TMOTNSB" (trade name) of Teijin Ltd., hereinafter referred to as "PET" fiber] is 0.
Absorption paper having a basis weight of 80 g / m ² was obtained by performing the same operations as in Production Example 13 except that these were uniformly dispersed in water to form a slurry so that the amount became 01%. This absorbent paper is
75 parts of cellulose fiber (D) based on 100 parts of absorbent paper
Parts, 20 parts of hydrophilic fine fibers (A), and 5 parts of the PET fibers.

[Production Example 16] Production of absorbent paper The concentration of cellulose fibers (D) was 0.17%, the concentration of hydrophilic fine fibers (C) was 0.02%, and the concentration of the PVA fibers was 0. These were uniformly dispersed in water to obtain a slurry to obtain a slurry of 01%. This slurry was sprinkled on a wire netting paper wire having a wire opening diameter of 26 μm (518 mesh) to form a paper layer on the wire netting paper wire. Using a suction box, 6 ml / [cm ² · sec
] The paper layer was dehydrated at a speed of. Then, after the paper layer was dried with a dryer, 10% of crepe was applied to obtain an absorbent paper having a basis weight of 80 g / m ² . This absorbent paper contained 85 parts of the cellulose fibers (D), 10 parts of the hydrophilic fine fibers (C), and 5 parts of the PVA fibers based on 100 parts of the absorbent paper.

Production Example 17 Production of Absorbent Paper Cellulose fiber (C) concentration was 0.16%, hydrophilic fine fiber (A) concentration was 0.03%, and the PET fiber concentration was 0. Absorption paper having a basis weight of 80 g / m ² was obtained by performing the same operations as in Production Example 13 except that these were uniformly dispersed in water to form a slurry so that the amount became 01%. This absorbent paper contained 80 parts of the cellulose fibers (C), 15 parts of the hydrophilic fine fibers (A), and 5 parts of the PET fibers based on 100 parts of the absorbent paper.

Comparative Production Example 1 Production of Absorbent Paper The same operation as in Production Example 13 was carried out except that cellulose (E) was used instead of cellulose fiber (A), and a basis weight of 80 g
An absorbent paper of / m ² was obtained.

Comparative Production Example 2 Production of Absorbent Paper The same operation as in Production Example 14 was carried out except that cellulose (G) was used instead of the cellulose fiber (B), and the basis weight was 80 g.
An absorbent paper of / m ² was obtained.

Comparative Production Example 3 Production of Absorbent Paper Cellulose fiber (F) concentration was 0.16%, hydrophilic fine fiber (D) concentration was 0.03%, and the PET fiber concentration was 0. Absorbing paper having a basis weight of 80 g / m ² was obtained by performing the same operation as in Production Example 13 except that these were uniformly dispersed in water to form a slurry so that the amount became 0.01%. This absorbent paper contained 80 parts of the cellulose fibers (F), 15 parts of the hydrophilic fine fibers (D), and 5 parts of the PET fibers based on 100 parts of the absorbent paper.

Comparative Production Example 4 Production of Absorbent Paper Cellulose fiber (G) concentration was 0.16%, hydrophilic fine fiber (E) concentration was 0.03%, and the PET fiber concentration was 0. Absorbing paper having a basis weight of 80 g / m ² was obtained by performing the same operation as in Production Example 13 except that these were uniformly dispersed in water to form a slurry so that the amount became 0.01%. This absorbent paper contained 80 parts of the cellulose fibers (G), 15 parts of the hydrophilic fine fibers (E), and 5 parts of the PET fibers based on 100 parts of the absorbent paper.

Comparative Production Example 5 Production of Absorbent Paper Cellulose fiber (D) concentration was 0.08%, hydrophilic fine fiber (E) concentration was 0.04%, and the PET fiber concentration was 0. Absorbing paper having a basis weight of 80 g / m ² was obtained by performing the same operations as in Production Example 13 except that these were uniformly dispersed in water to form a slurry so that the amount became 0.08%. This absorbent paper contained 40 parts of the cellulose fibers (D), 20 parts of the hydrophilic fine fibers (E), and 40 parts of the PET fibers based on 100 parts of the absorbent paper.

[Comparative Production Example 6] Production of absorbent paper The concentration of cellulose fibers (E) was adjusted to 0.2%,
Except that this is uniformly dispersed in water to form a slurry,
The same operation as in Production Example 13 was performed to obtain an absorbent paper having a basis weight of 80 g / m ² . This absorbent paper consists only of cellulose fibers (E).

Comparative Production Example 7 Production of Absorbent Paper Production Example except that the hydrophilic fine fibers (D) were uniformly dispersed in water to form a slurry so that the concentration of the hydrophilic fine fibers (D) was 0.2%. Perform the same operation as in No. 13, and weigh 80 g / m ²
The absorbent paper of This absorbent paper consists only of hydrophilic fine fibers (D).

Production Examples 13 to 17 and Comparative Production Examples 1 to 1
The following measurements were performed on the absorbent paper obtained in 7. The results are shown in Table 2.

<Measurement of Absorption Time> As shown in FIG. 9, the absorption paper 51 (200 mm × 75 mm) is placed horizontally, and the diameter is 10 mm.
An acrylic plate 52 having an injection port 54 of mm is placed thereon, and a weight 53 is further placed on the acrylic plate 52 so that the weight of the absorbent paper 51 is 5 g /
A load of cm ² was applied. Next, 6 g of defibrinated horse blood [manufactured by Japan Biotest Institute Co., Ltd.] was injected from the injection port 54,
The time until the defibrinated horse blood was completely absorbed was measured.
The absorption time was defined as the average of 5 measurements.

<Measurement of Diffusion Area> As shown in FIG. 10, the absorbent paper 51 (200 × 75 mm) was placed horizontally so that the “front side” was the upper side, and the diameter was measured from the microtube pump 60. Tube 61 with 2 mm inlet
Through 1g of saline solution 62 at a speed of 1g / 10 seconds
Was injected into the absorbent paper 51. The distance between the tip of the tube 61 and the absorbent paper was about 10 mm. Saline is 0.0
It was colored with 1% food blue No. 1 (Tokyo Chemical Industry Co., Ltd.) and used. About 1 minute after injection of physiological saline, the diffusion area (cm ² ) on the “surface” of the absorbent paper was accurately traced and measured by an image analyzer. The same operation is performed by horizontally setting the absorbent paper 51 so that the “rear surface” of the absorbent paper 51 is on the upper side, accurately tracing the diffusion area (cm ² ) of the “rear surface”, and using the image analysis device. It was measured. Next, the diffusion area ratio between the "front side" and the "back side" of the absorbent paper was obtained by rounding off to the second decimal place according to the following formula.

[0129]

(Equation 3)

<Evaluation of Surface State after Absorption of Liquid> As shown in FIG. 10, the absorbent paper 51 (200 × 75 mm) was placed horizontally so that the “front side” was the upper side, and the microtube pump was used. From 60, 3 g of physiological saline was injected into the absorbent paper 51 at a speed of 1 g / 10 seconds through a tube 61 having an inlet having a diameter of 2 mm. Approximately 1 minute after the injection of physiological saline, a sensory evaluation of the "latency" of the "surface" of the absorbent paper was performed. The same operation was performed by horizontally installing the absorbent paper 51 so that the "back surface" of the absorbent paper 51 was on the upper side. The evaluation criteria are as follows.

◯: The physiological saline is hardly retained on the absorbent paper, and there is a feeling of slat. Δ: A little saline is retained on the absorbent paper, but there is some sensation of slat. X: A considerable amount of physiological saline remains on the absorbent paper, and it feels sticky.

[0132]

[Table 2]

As is clear from the results shown in Table 2, the absorbent papers in the production examples have a fast absorption time, have a liquid diffusion gradient, and are excellent in slatiness. On the other hand, the absorbent paper in the comparative production example has a diffusion area ratio of 1 because there is no diffusion gradient related to the diffusibility of the liquid in the thickness direction.

Example 1 Production of Absorbent Article A sanitary napkin 10 shown in FIG. 5 was produced. Production Example 13
The absorbent paper (length: 195 mm, width: 160 mm) obtained in (1) was used as the absorbent paper 22A. In the area of length 195 mm and width 70 mm on the "rear surface" side of the absorbent paper 22A, the super absorbent polymer 22
B was dispersed substantially uniformly so that the amount of spray was 50 g / m ² . Next, the absorbent paper 22A is folded inward, and the high-absorbent polymer 22B is wrapped with the absorbent paper 22A.
2 was manufactured (therefore, the "front surface" side of the absorbent paper 22A corresponds to the outside of the absorbent body 22). The width of the absorber 22 was 75 mm. As the superabsorbent polymer 22B, sodium polyacrylate [Polymer Q (trade name) of Kao Corporation] was used. The absorbent body 22 was wrapped with polyethylene laminated paper (leak-proof material 23), and the combination of the absorbent body 22 and the leak-proof material 23 was further wrapped with the surface material 21. Then, the surface material 21, the absorber 22, and the leak preventer 23 were fixed to each other with an adhesive 26. In addition, as the surface material 21, as shown in FIG.
The perforated film shown in (A) to (C) was used. The perforated film is formed by melt extruding low-density polyethylene from a T-die to form a film on the spiral woven wire mesh shown in FIGS. 7 (A) and (B), and then sucking the film. . Further, on the lower surface side of the sanitary napkin 10, three adhesive portions 24 were formed in a stripe shape in the longitudinal direction. The adhesive section 24 is protected by a release paper 25.

Examples 2 to 5 and Comparative Examples 1 to 7 Production of Absorbent Articles Production Examples 14 to 17 in place of the absorbent paper obtained in Production Example 13
And the sanitary napkin was manufactured in the same manner as in Example 1 except that the absorbent papers obtained in Comparative Production Examples 1 to 7 were used.

With respect to the sanitary napkins obtained in Examples 1 to 5 and Comparative Examples 1 to 7, the absorption time, the amount of dynamic liquid return and the leak test (number of leak occurrences) were measured by the following methods. Table 3 shows the results.

<Absorption time and amount of dynamic liquid return> In the apparatus for measuring the liquid absorption time of absorbent paper shown in FIG. 9, the sanitary napkin 10 is placed horizontally instead of the absorbent paper 51, and the diameter is 10 mm.
Place the acrylic plate 52 having the injection port 54 of
Place a weight 53 on top of it and put 5 on the sanitary napkin 10.
A load of g / cm ² was applied. Next, 6 g of defibrinated horse blood (manufactured by Japan Biotest Institute Co., Ltd.) was injected from the injection port 54, and the time until the defibrinated horse blood was completely absorbed was measured.

After the defibrinated horse blood is completely absorbed, it is allowed to stand for 20 minutes. Then, this sanitary napkin 10
Paper (length 195 mm x width 75 mm,
Ten sheets of the basis weight of 30 g / m ² ) were stacked and the sanitary napkin 10 and the paper in this state were mounted on the female waist model 70 shown in FIG. 11 as shown in FIG. Next, the female waist model 70 was fitted with shorts, and then walked at a walking speed of 100 steps / minute (50 m / minute). After walking, the sanitary napkin 10 and 10 sheets of paper were taken out, and the weight of defibrinated horse blood absorbed in the paper was measured. This is defined as the dynamic liquid return amount (g).

The absorption time and the dynamic liquid return amount were measured 10 times, and the average value was used as the absorption time and the dynamic liquid return amount.

<Leak Test (Number of Leak Occurrences)> Examples 1 to 1
5 and the sanitary napkins obtained in Comparative Examples 1 to 7 are shown in FIG.
The female waist model 70 shown in Fig. 12 was attached as shown in Fig. 12. Next, the female waist model 70 was fitted with shorts, and then walked at a walking speed of 100 steps / minute (50 m / minute).

After that, 3 g of defibrinated horse blood was injected into the sanitary napkin through the tube 71 while walking, and then walked at the same speed for 10 minutes (total amount 3 g), and then defibrinated horse blood was applied to the sanitary napkin. After injecting 3g into
At the time of walking at the same speed for 10 minutes (total amount of 6 g), after further injecting 3 g of defibrinated horse blood into the sanitary napkin, at the same speed of walking for 10 minutes (total amount of 9 g), the number of samples was 10 at each time point. The number of leaks was counted.

[0142]

[Table 3]

As is clear from the results shown in Table 3, the absorbent article of the present invention has a very simple structure, but has a quick liquid absorption time, a small liquid return amount, and the number of leaks. It has extremely low performance and very high performance. this is,
Since the absorbent paper used in the absorbent article of the present invention has an absorption / diffusion gradient of liquid in its single structure, it absorbs liquid quickly and allows liquid to smoothly pass through the absorbent paper. Moreover, this is because the liquid is sufficiently diffused on the "back surface" side of the absorbent paper.

[0144]

The absorbent paper used in the absorbent article of the present invention has a liquid absorption / diffusion gradient in its single structure, and therefore has a high liquid absorption rate and liquid spot absorption. And the permeability and diffusivity of liquid, resulting in
The surface has a very high feeling of slat. Therefore, the absorbent article of the present invention has extremely high absorbency, little liquid leakage, is extremely thin, and is excellent in wearing feeling.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section in the thickness direction of absorbent paper used in an absorbent article of the present invention.

FIG. 2 is a schematic diagram showing the state of liquid absorption / diffusion by the absorbent paper used in the absorbent article of the present invention.

FIG. 3 is a schematic diagram showing a preferred method for producing absorbent paper used in the absorbent article of the present invention.

FIG. 4 is an enlarged view of part (a) of FIG.

FIG. 5 is a schematic view showing a cross section in the width direction of a sanitary napkin as an embodiment of the absorbent article of the present invention.

FIG. 6 is a schematic view (corresponding to FIG. 5) showing a cross section in the width direction of a sanitary napkin as another embodiment of the absorbent article of the present invention.

FIG. 7 is a view showing a spiral braided wire mesh for producing a liquid-permeable surface material.

FIG. 8 is a schematic diagram showing a liquid-permeable surface material.

FIG. 9 is a schematic diagram showing an absorption time measuring device.

FIG. 10 is a schematic view showing a device for measuring a diffusion area.

FIG. 11 is a schematic view showing a female waist model.

FIG. 12 is a schematic diagram showing a state in which an absorbent article is attached to a female waist model.

[Explanation of symbols]

 10 Sanitary Napkins 11 Absorbing Paper 12 Bulky Cellulose Fibers 13 Hydrophilic Fine Fibers or Hydrophilic Fine Powders 14 Slurry 15 Paper Making Wire 16 Paper Layer 17 Network Structure 21 Liquid Permeable Surface Material 22 Liquid Retaining Absorber 23 Liquid impermeable leak preventer 24 Adhesive part 25 Release paper 26 Adhesive

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B32B 5/26 A41B 13/02 D // D21H 11/20 D21H 5/22 C 5/14 Z

Claims (10)

[Claims] 1. An absorbent article comprising a liquid-permeable surface material, a liquid-impermeable leak-proof material, and a liquid-retaining absorber interposed between the surface material and the leak-proof material. The absorbent body comprises absorbent paper and a superabsorbent polymer, and the absorbent paper contains bulky cellulose fibers and hydrophilic fine fibers or hydrophilic fine powders, and the hydrophilic The presence ratio of the fine fibers or the hydrophilic fine powder in the one surface side of the absorbent paper is higher than that in the other surface side, and the average fiber length of the bulky cellulose fibers is 1 to 20 mm.
And the average fiber length of the hydrophilic fine fibers is 0.02 to 0.5.
mm, and the average particle diameter of the hydrophilic fine powder is 0.02 to 0.5 mm. 2. 50 to 97 parts by weight of the bulky cellulose fiber, and 3 to 50 parts of the hydrophilic fine fiber or the hydrophilic fine powder based on 100 parts by weight of the absorbent paper.
The absorbent article according to claim 1, comprising parts by weight. 3. A heat-melting adhesive fiber is further included; 70 to 95 parts by weight of said bulky cellulose fiber based on 100 parts by weight of said absorbent paper, said hydrophilic fine fiber or said hydrophilic fine powder. 5 to 30 parts by weight and 2 to 30 parts by weight of the hot-melt adhesive fiber; and the basis weight of the absorbent paper is 10 to 200 g / m ² , the absorbent article according to claim 1 or 2. 4. The bulky cellulose fiber is 0.3 mg.
The absorbent paper according to claim 1, wherein the absorbent paper has a density of not less than / m. 5. The absorbent article according to claim 1, wherein the bulky cellulose fibers have an average fiber length of 2 to 5 mm. 6. The absorbent article according to claim 4, wherein the bulky cellulose fiber is a crosslinked pulp. 7. The absorbent article according to claim 4, wherein the bulky cellulosic fiber is pulp having a circularity of 0.5 to 1 in a fiber cross section. 8. The absorbent article according to claim 1, wherein the hydrophilic fine fibers are cellulose fibers, and the hydrophilic fine powder is cellulose powder. 9. The absorbent article according to claim 1, wherein a diffusion area ratio between the front surface side and the back surface side when the absorbent paper absorbs 1 g of physiological saline is 1.2 or more. 10. The absorbent article according to claim 1, wherein the absorber comprises the absorbent paper sandwiched between the absorbent papers.