JP2008029830A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article which has a high liquid absorption speed, is excellent in spot absorbabilty, and has a small liquid returning amount. <P>SOLUTION: The absorbent article 1 by this invention includes a cellulose-based hydrophilic fiber which contains one or more kinds of surfactants selected from a group consisting of a sugar alkyl ether and a sugar fatty acid ester at a site other than the part 20 to be in contact with the skin. As a site other than the part 20 to be in contact with the skin, an absorber 4 or a second sheet 5 can be cited. The cellulose-based hydrophilic fiber may be contained in a fiber mass 42 constituting the absorber 4 or a coating sheet 44. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an absorbent article.

In an absorbent article such as a sanitary napkin, menstrual blood or the like absorbed by the absorbent body from the skin contact surface may return to the skin contact surface due to pressurization or the like and become sticky.
As a method for reducing stickiness, it has been practiced to provide unevenness on the surface sheet that forms the skin contact surface to reduce the contact area with the skin or to use a bulky nonwoven fabric for the surface sheet.
Moreover, in absorbent articles, in order to improve the absorption performance of the absorber, improvement of the superabsorbent polymer used in the absorber, modification of the retention mode of the superabsorbent polymer in the absorber, the three-dimensional structure of the absorber, etc. Studies on these are also being conducted.
However, the performance required for the absorbent article is increasing year by year, and there is a possibility that the conventional method cannot sufficiently meet future demands.

  Patent Document 1 describes a water-decomposable sheet in which a mixed substance having a melting point peak temperature of two or more points is applied to at least a surface of the base sheet having water-decomposability that is in contact with the skin. A sucrose ester is described as an example of the components. However, in the invention described in Patent Document 1, in order to improve the moist feeling when touching the skin, a mixed material having two or more melting point peaks is applied to the base sheet. No mention is made regarding the use of the water-decomposable sheet at a site other than the skin contact surface in the absorbent article.

JP 2005-290618 A

  An object of the present invention is to provide an absorbent article that has a high liquid absorption rate, is excellent in spot absorbability, and has a low liquid return amount.

  The present invention achieves the above object by providing an absorbent article comprising cellulosic hydrophilic fibers containing one or more surfactants selected from the group consisting of sugar alkyl ethers and sugar fatty acid esters. Is.

  The absorbent article of the present invention has a high liquid absorption rate, excellent spot absorptivity, and a low liquid return amount.

The present invention will be described below based on preferred embodiments with reference to the drawings.
As shown in FIG. 1, a sanitary napkin 1 (hereinafter also referred to as a napkin 1) as an embodiment of the present invention includes a liquid-permeable surface sheet 2 that forms a skin contact surface 20, a liquid-impermeable or A water-repellent leak-proof sheet 3 and an absorbent body 4 positioned between the two sheets 2 and 3 are provided, and a second sheet (intermediate layer) 5 is provided between the top sheet 2 and the absorbent body 4.
The absorbent body 4 includes a fiber aggregate 42 made of pulp fibers and an absorbent core 41 made of a superabsorbent polymer 43, a covering sheet 44 that covers the skin contact surface side of the absorbent core 41, and the absorbent core 41. And a covering sheet 45 that covers the non-skin contact surface side. The covering sheet 44 and the covering sheet 45 may be a single continuous sheet or two separate sheets.

The napkin 1 includes cellulosic hydrophilic fibers containing one or more surfactants selected from the group consisting of sugar alkyl ethers and sugar fatty acid esters at sites other than the skin contact surface 20.
The skin contact surface 20 is a surface that comes into contact with the wearer's skin when worn, and the non-skin contact surface 30 is a surface that is directed to the opposite side of the wearer's skin when worn.

The site other than the skin contact surface is a purpose of excluding the surface on the skin contact surface 20 side of the sheet forming the skin contact surface 20 (surface sheet 2 in the present embodiment). When the layer has a multilayer structure, among the layers constituting the top sheet 2, layers other than the outermost layer forming the skin contact surface 20 are included in portions other than the skin contact surface. Further, the sheet forming the skin contact surface 20 is a single-layer sheet containing cellulosic hydrophilic fibers, and the surfactant only on the back surface (surface opposite to the skin contact surface) side. Is applied to the case where the cellulosic hydrophilic fiber containing the surfactant is contained in a portion other than the skin contact surface 20.
In addition, when the skin contact surface 20 is treated with the above-described surfactant, the excretion fluid easily flows (laterally diffuses) on the surface of the topsheet 2, and the excretion fluid is less likely to enter the absorber 4, This is not preferable because it tends to cause leakage.

The surfactant used in the present invention is a sugar alkyl ether and / or a sugar fatty acid ester.
The sugar alkyl ether has a structure in which a sugar residue and an alkyl group are single-bonded to oxygen. When G is a sugar residue and R ₁ is an alkyl group, the sugar alkyl ether can be represented by the general formula G—O—R _1. it can.
Examples of sugar alkyl ethers include monosaccharides or polysaccharide alkyl ethers obtained by condensing two or more monosaccharides. From the viewpoint of spot absorbability, monosaccharides or C1-C60 alkyl ethers of polysaccharides condensed with 2 to 30 monosaccharides are preferred, and alkyl glucosides in which the sugar component is a monosaccharide are more preferred.

  As the alkyl glucoside, those having 1 to 22 carbon atoms in the alkyl group are preferable in terms of spot absorbability and liquid absorption rate, more preferably those having 4 to 18 carbon atoms, more preferably 8 to 14 carbon atoms in the alkyl group. It is. The alkyl group may be linear or branched. The alkyl chain length may be distributed, but those having an alkyl chain length in the above range are preferably present in an amount of 60 wt% or more based on the total alkyl groups.

Moreover, the etherification degree of alkyl glucoside is, when the etherification degree is 100% when all five hydroxyl groups present in one glucose molecule are alkyl etherified,
It is preferably a single compound or a mixture having a degree of etherification in the range of 2 to 60%, more preferably from 5 to 45%, and still more preferably from 15 to 35%, from the viewpoint of liquid absorption rate and spot absorbability. It is.

  The sugar fatty acid ester is a nonionic surfactant in which a sugar and a saturated fatty acid or an unsaturated fatty acid are ester-bonded, and examples thereof include a fatty acid ester of a polysaccharide obtained by condensing two or more monosaccharides or monosaccharides. From the viewpoint of spot absorptivity, a monosaccharide or a fatty acid ester having 1 to 60 carbon atoms of a polysaccharide condensed with 2 to 30 monosaccharides is preferable, and a fatty acid ester of sucrose which is a disaccharide is more preferable.

The constituent fatty acid of the sucrose fatty acid ester may be an alkyl group or an alkenyl group having an alkyl group, an alkenyl group, a phenyl group or a phenylene group, wherein R when represented by the general formula RCOOH has 1 to 30 carbon atoms. From the viewpoint of spot absorptivity and liquid absorption rate, more preferred are alkyl groups and alkenyl groups having 4 to 22 carbon atoms, and still more preferred are alkyl groups and alkenyl groups having 8 to 18 carbon atoms. These fatty acids may be linear or branched. The alkyl chain length and the alkenyl chain length may be distributed, but those having an alkyl chain length and alkenyl chain length within the above range should be present in an amount of 60 wt% or more based on all alkyl groups and alkenyl groups. .
The esterification degree (ester substitution degree) of sucrose fatty acid ester is such that the esterification degree is 2 if the esterification degree is 100% when all eight hydroxyl groups present in one molecule of sucrose are esterified. It is preferably a single compound or a mixture in the range of ˜60%, more preferably 5 to 45%, further preferably 15 to 35% from the viewpoint of the liquid absorption rate and spot absorbability.

The alkyl glucoside and sucrose fatty acid ester used as the surfactant preferably have an HLB of 4 to 20, more preferably 9 to 20 and even more preferably from the viewpoint of further improving the liquid absorption rate and spot absorbability. 12-18. The HLB used in the present invention is a W.W. C. This is a value calculated using the Griffin equation (J. soc. Cosm. Chemists 5 , S. 249, 1954).

Examples of the cellulose-based hydrophilic fiber containing a surfactant include pulp fiber, cotton, rayon, cupra, lyocell, hemp and the like. These fibers can be used singly or in combination of two or more. The cellulose-based hydrophilic fiber is preferably composed mainly of pulp fiber from the viewpoint of further improving the liquid absorption rate.
Moreover, although the cellulosic hydrophilic fiber containing surfactant is not specifically limited, It is preferable from the point of a texture and handling that it contains 3-30 mm in length and a fiber of 5-100 micrometers in diameter. The fiber having such a length and diameter is the total amount of the cellulosic hydrophilic fiber in the material containing the cellulosic hydrophilic fiber containing a surfactant (for example, a covering sheet, an absorbent core, an intermediate layer, etc.). The content is preferably 50 to 100% by weight, and more preferably 80 to 100% by weight. When the cross section of the cellulosic hydrophilic fiber is not a perfect circle, the diameter is measured on the long axis of the cross section. In this case, it is preferable that the diameter of 10 or more cellulosic hydrophilic fibers is measured, and the average value thereof is in the range of the diameter.
Cellulosic hydrophilic fibers and fibers other than cellulosic hydrophilic fibers can also be mixed and used. In that case, the proportion of cellulosic hydrophilic fibers is preferably 50% by weight or more, more preferably 70%. % By weight, more preferably 90% by weight or more.

The napkin 1 in the present embodiment includes cellulose-based hydrophilic fibers containing the above-described surfactant in the absorber 4 and / or the second sheet (intermediate layer) 5.
Specifically, all of the fiber assembly 42, the covering sheet 44, and the second sheet 5 are mainly composed of pulp fibers, and at least some of the pulp fibers contain the surfactant described above. Yes. The fiber aggregate 42, the covering sheet 44, and the second sheet 5 each have a pulp fiber content of preferably 50% or more, more preferably 70% or more, and even more preferably 90% or more. .

The method for incorporating the above-described surfactant into the cellulosic hydrophilic fiber is not particularly limited. For example, a liquid containing the surfactant (for example, a water-diluted solution) is sprayed or applied to the cellulosic hydrophilic fiber. And a method of immersing a cellulose-based hydrophilic fiber in a liquid containing the surfactant.
The cellulose-based hydrophilic fiber containing a surfactant may be one in which the above-mentioned surfactant is attached to the surface or may contain the above-described surfactant inside. Further, the above-described surfactant may be adhered to the surface and may contain a surfactant inside.

The amount of the surfactant used is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the cellulose-based hydrophilic fiber in the absorbent body 4 before containing the surfactant. 05 to 5 parts by weight, more preferably 0.1 to 1 part by weight, particularly preferably 0.5 to 1 part by weight. These ranges are preferable from the viewpoint of ensuring the effect of the present invention more reliably and reducing the waste of the surfactant in relation to the counter effect. Moreover, when there is too much usage-amount of surfactant, the fall of blood viscosity will become large and it may become easy to return to a liquid, and the said range is preferable also from a viewpoint of preventing it. As used herein, the amount of surfactant used is the amount of surfactant remaining in the completed absorbent article.
When the absorbent body 4 includes a cellulosic hydrophilic fiber containing a surfactant and the superabsorbent polymer 43 as in the napkin 1 of the present embodiment, the superabsorbent polymer 43 in the absorbent body 4 The content ratio is preferably 5 to 300 parts by weight, more preferably 10 to 250 parts by weight, more preferably 100 parts by weight of the cellulose-based hydrophilic fiber in the absorbent body 4 before containing the surfactant. Is 15 to 200 parts by weight, particularly preferably 20 to 120 parts by weight. These ranges are preferable from the viewpoint of the liquid return amount.

  According to the napkin 1 of the present embodiment, by including the cellulosic hydrophilic fiber containing the surfactant in a portion other than the skin contact surface, the absorption rate is faster and the spot absorbability compared to the case where it is not included. Excellent liquid return amount. The reason why such an effect is obtained is not yet completely understood, but the blood supplied on the top sheet 2 comes into contact with the surfactant in the second sheet 5 and / or the absorber 4 and It is considered that the blood is more easily drawn into the absorber 4 due to the change in the viscosity and surface tension of the blood, and the blood is more easily absorbed by the superabsorbent polymer. It is not preferable to add an agent other than the above-mentioned surfactant in order to prevent the blood from being easily absorbed by the superabsorbent polymer.

The material for forming each part of the napkin 1 of the present embodiment will be described. As the top sheet 2 and the leak-proof sheet 3, those conventionally used for this type of article can be used without any particular limitation. For example, as the surface sheet, nonwoven fabrics produced by various manufacturing methods, those obtained by forming holes in a resin film, laminates of these, and the like can be used. As the leak-proof sheet 3, a film of a thermoplastic resin with or without moisture permeability, a water-repellent nonwoven fabric, or a laminate thereof can be used.
As the fiber assembly 42, the covering sheets 44 and 45, and the second sheet 5, it is possible to use only cellulose-based fibers, or nonwoven fabrics containing cellulose-based fibers, non-woven fabrics, nonwoven fabrics or web laminates, respectively. it can. Further, any one of the fiber assembly 42, the covering sheets 44 and 45, and the second sheet 5 only needs to contain cellulosic fibers, and the others do not contain cellulosic fibers, non-woven fabrics, non-woven fabrics, and non-woven fabrics. Or a laminate of webs can be used. When the covering sheets 44 and 45 include cellulosic hydrophilic fibers containing a surfactant, it is preferable that the covering sheet 44 that covers at least the skin contact surface side of the absorbent core 41 includes the fibers.
The covering sheet 44 is preferably liquid permeable and has high wet strength.

  As the superabsorbent polymer 43, those conventionally used for this type of article can be used without particular limitation, but those which can absorb a liquid having a weight 20 times or more of its own weight and can be gelled are preferable. Polyacrylic acid and its alkali metal salts (partially or completely neutralized products), and polyacrylate graft polymers, such as copolymers of cross-linked carboxylmethylated cellulose, acrylic acid or alkali metal acrylates and other monomers, etc. Can be mentioned. Particularly preferred is an alkali metal polyacrylate (partially or completely neutralized product). These superabsorbent polymers can be used alone or in combination of two or more.

As mentioned above, although preferable embodiment of this invention was described, the absorbent article of this invention is not limited to the said embodiment, It can change suitably.
For example, in the above-described napkin 1, each of the fiber assembly 42, the covering sheet 44, and the second sheet (intermediate layer) 5 is mainly composed of pulp fibers, and at least a part of each of the pulp fibers contains a surfactant. However, instead of this, only the pulp fibers constituting the fiber assembly 42 may contain a surfactant.
Moreover, only the pulp fiber which comprises the coating sheet 44 may contain surfactant.
Furthermore, only the pulp fibers constituting the second sheet (intermediate layer) 5 may contain a surfactant.
Even if only the fiber aggregate 42 contained in the absorbent core 41, only the covering sheet 44, and only the second sheet 5 are treated with the surfactant, the effect of reducing the liquid absorption rate, spot absorptivity, and liquid return amount can be seen. It is done.

  In the above-described embodiment, the second sheet 5 and the covering sheets 44 and 45 may be used as necessary, and may be omitted if not necessary.

  Further, as shown in FIG. 1, the superabsorbent polymer 43 in the absorbent core 41 is not substantially uniformly dispersed and held in the fiber assembly 42, but the surface in the thickness direction of the fiber assembly 42. It may be biased and present on the sheet side, the leak-proof sheet side or near the center. Alternatively, the superabsorbent polymer 43 may be sandwiched between layers of a fiber assembly composed of a plurality of layers.

  In addition to sanitary napkins, the absorbent article in the present invention may be a panty liner (cage sheet), an incontinence pad, a disposable diaper, or the like.

The absorbent article of the present invention may be one in which the surfactant is evenly distributed in the plane direction of the fiber layer containing the cellulose-based hydrophilic fiber containing the surfactant. A region where the surfactant is applied and a region where the surfactant is not applied may coexist in the planar direction. The plane direction of the fiber layer is a direction orthogonal to the thickness direction of the fiber layer.
In the fiber layers (second sheets made of nonwoven fabric, etc.) 5A, 5B shown in FIGS. 2 (a) and 2 (b), a region 50 where the surfactant is applied in the planar direction of the fiber layers 5A, 5B. And a region 51 where the surfactant is not applied are mixed in a predetermined pattern. The area ratio (region 50: region 51) between the region 50 to which the surfactant is applied and the band-like region 51 to which the surfactant is not applied can be, for example, 10:90 to 80:20.
Further, when the region 50 where the surfactant is applied and the region 51 where the surfactant is not applied are mixed in the plane direction of the fiber layer, the surfactant can be applied by a brush, a spray nozzle or the like, In particular, the application method is not limited.

In the fiber layer 5A shown in FIG. 2 (a), the region 50 to which the surfactant is applied is formed in a stripe shape. Specifically, a large number of band-like regions 50 to which the surfactant is applied are formed so as to extend in one direction of the fiber layer 5A, and the surfactant is applied between the adjacent band-like regions 50. A non-banded region 51 is interposed.
In the fiber layer 5A, the width of the band-shaped region 50 can be set to 2 to 20 mm, for example, and the width of the band-shaped region 51 can be set to 1 to 10 mm, for example.
By mixing the region 50 to which the surfactant is applied and the region 51 to which the surfactant is not applied, blood is easily absorbed into the absorber by the surfactant or absorbed by the superabsorbent polymer. There is a region 51 that can be easily modified and has high hydrophilicity without being coated with a surfactant. As a result, the absorption rate and the liquid return amount can be improved with good balance.
Further, since the fiber layer 5A easily flows in the direction in which the belt-like region 50 extends and the liquid does not easily flow in the direction orthogonal to the direction in which the belt-like region 50 extends, the direction in which the region 50 extends is defined by the absorbent article. By incorporating it into the absorbent article so as to coincide with the longitudinal direction (the longitudinal direction of the wearer when worn), the liquid leakage prevention property from the side of the absorbent article is improved.

In the fiber layer 5 </ b> B shown in FIG. 2B, the region 50 to which the surfactant is applied is formed in a dot shape (scattered dot shape) with a space therebetween. The planar view shape of each region 50 is a circle, but may be an arbitrary shape such as a square, a rectangle, a diamond, or a heart instead of a circle. The area of each region 50 can be, for example, 5 to 100 mm ^2, and the distance between the center points of the adjacent regions 50 can be 3 to 10 mm. Also in the fiber layer 5B, the absorption rate and the liquid return amount can be improved in a well-balanced manner by mixing the region 50 to which the surfactant is applied and the region 51 to which the surfactant is not applied.

[Example 1]
1% water of surfactant (decylglucoside, trade name “Mydol 10”) manufactured by Kao Co., Ltd. on defibrated pulp fiber {average length 3 mm, diameter (long axis) 10-30 μm, wafer user NB416} The diluted solution was sprayed, and 0.6 parts by weight of decylglucoside was adhered to 100 parts by weight of pulp fibers. Then, it was left to dry for 2 hours in a blast constant temperature dryer having a temperature of 80 ° C. and a relative humidity of 3%. After drying, the pulp fibers were adjusted to predetermined dimensions (width 75 mm, length 200 mm, thickness 2 mm) to create an absorbent core. An absorbent paper having a basis weight of 200 g / m ² was obtained by covering the skin contact surface and the non-skin contact surface of the absorbent core with an absorbent paper (coating sheet) made of pulp fibers having a basis weight of 16 g / m ² . . In the obtained absorbent body, 0.5 part by weight of a surfactant is attached to 100 parts by weight of the cellulose-based hydrophilic fiber in the absorbent body. A surface sheet, a second sheet and a back sheet (leak-proof sheet) used for the obtained absorbent body and a commercially available sanitary napkin (trade name “Laurier Super Slim Guard for Daytime”, manufactured by Kao Corporation) A sanitary napkin was made.

[Examples 2 to 22]
According to Example 1, the same kind of surfactant as shown in Table 1 was attached to 100 parts by weight of the defibrated pulp fiber used in Example 1 so as to have the attached amount shown in Table 1, and dried. . The dried pulp fiber is mixed with 30 parts by weight of a superabsorbent polymer (AQUALIC CA-4 manufactured by Nippon Shokubai Co., Ltd.), and adjusted to predetermined dimensions (basis weight 168 g / m ² , width 75 mm, length 200 mm). Thus, an absorbent core that was a pulp fiber / superabsorbent polymer mixed sheet was prepared. An absorbent paper (coating sheet) made of pulp fibers having a basis weight of 16 g / m ² covers the skin contact surface and non-skin contact surface of the resulting absorbent core, and the pulp has a basis weight of 200 g / m ² . A fiber / superabsorbent polymer mixed absorbent was obtained.
A sanitary napkin was prepared in accordance with Example 1 using this pulp fiber / superabsorbent polymer mixed absorbent instead of the absorbent in Example 1.

Example 23
90 parts by weight of the defibrated pulp fiber used in Example 1 and 10 parts by weight of rayon fiber {length 10 to 20 mm, diameter (major axis) 10 to 24 μm} were mixed, and the surface activity used in Example 1 was mixed therewith. Spraying agent (decyl glucoside 1% water dilution) and adhering to 0.6 parts by weight of decyl glucoside to 100 parts by weight of mixed fiber of pulp fiber and rayon fiber, and drying according to Example 1 Went.
A sanitary napkin containing a superabsorbent polymer was prepared according to Examples 2 to 22 except that this mixed fiber was used as a fiber to which a surfactant was attached.

Example 24
An absorbent core that was a pulp fiber / superabsorbent polymer mixed sheet was prepared in the same manner as in Example 2 except that the surfactant was not attached to the pulp fiber.
On the other hand, a 1% water-diluted solution of the surfactant (decylglucoside) used in Example 1 is sprayed onto an absorbent paper (coating sheet) made of pulp fibers having a basis weight of 16 g / m ^{2, and} the pulp in the absorbent core described above. 0.6 parts by weight of decylglucoside was attached to 100 parts by weight of the total cellulosic hydrophilic fibers (pulp fibers) in the absorbent body including the fibers. Then, it was left to dry for 2 hours in a blast constant temperature dryer having a temperature of 80 ° C. and a relative humidity of 3%.
The entire absorbent core described above was covered with an absorbent paper (covering sheet) to which a surfactant was attached to prepare an absorbent body. Thereafter, a sanitary napkin was prepared by the same operation as in Example 1.

Example 25
An absorbent core having a basis weight of 170 g / m ² pulp fiber / superabsorbent polymer mixed sheet was prepared in the same manner as in Example 2 except that the surfactant was not attached to the pulp fiber to obtain an absorbent body.
On the other hand, a 1% water-diluted solution of the surfactant (decylglucoside) used in Example 1 was sprayed onto a pulp sheet having a basis weight of 30 g / m ² made of crosslinked pulp fiber (HighBulkAdditive manufactured by Wafer User Co., Ltd.). 2.4 parts by weight of decylglucoside was adhered to 100 parts by weight of the crosslinked pulp fiber. Then, it was left to dry for 2 hours in a blast constant temperature dryer having a temperature of 80 ° C. and a relative humidity of 3%. After drying, it was adjusted to a predetermined dimension (width 75 mm, length 200 mm). The surfactant was uniformly and uniformly attached in the plane direction of the pulp sheet (direction perpendicular to the thickness direction).
The obtained pulp sheet was laminated | stacked on the skin contact surface side of the above-mentioned absorber as a second sheet. A sanitary napkin was prepared in the same manner as in Example 1 except that the absorbent body and the second sheet thus obtained were used. The same surface sheet and back sheet as in Example 1 were used.
The decyl glucoside in the sanitary napkin is not attached to the absorbent body, but the amount used is 0.6 parts by weight with respect to 100 parts by weight of the cellulose-based hydrophilic fiber in the absorbent body. It was 0.5 weight part with respect to 100 weight part of cellulosic hydrophilic fibers which added the cross-linked pulp fiber and the pulp fiber in an absorber.

Example 26
In the same pulp sheet as used in Example 25, a strip-shaped region (width 2 mm) coated with a surfactant and a strip-shaped region (width 3 mm) not coated with a surfactant are alternately formed. A 2% water dilution of the surfactant (decylglucoside) used in Example 1 was applied with a brush. Similarly to the fiber layer 5A shown in FIG. 2A, the belt-like region 50 coated with the surfactant and the belt-like region 51 not coated with the surfactant are each extended in one direction of the pulp sheet. Formed. Further, the area ratio (region 50: region 51) between the region 50 to which the surfactant was applied and the region 51 to which the surfactant was not applied was 3: 2. The usage-amount of surfactant was 2.4 weight part with respect to 100 weight part of crosslinked pulp fibers of a pulp sheet.
A sanitary napkin was prepared in the same manner as in Example 25 except that the pulp sheet coated with the surfactant was used as the second sheet.
The surfactant in the sanitary napkin is not attached to the absorbent body, but the amount used is 0.6 parts by weight with respect to 100 parts by weight of the cellulosic hydrophilic fiber in the absorbent body. It was 0.5 weight part with respect to 100 weight part of cellulosic hydrophilic fibers which added the cross-linked pulp fiber in the inside and the pulp fiber in the absorber.

Example 27
The surfactant (decylglucoside) used in Example 1 was diluted with 2% water so that a circular region coated with the surfactant was formed in the same pulp sheet as used in Example 25 in a dispersed state. The liquid was applied with a brush. Similarly to the fiber layer 5B shown in FIG. 2 (b), the circular regions coated with the surfactant were arranged in a staggered pattern. The area of each circular region was 78 mm ^2, and the distance between the center points of adjacent circular regions 50 was 15 mm. The area ratio (region 50: region 51) between the region 50 to which the surfactant was applied and the region 51 to which the surfactant was not applied was 78:63. The usage-amount of surfactant was 2.4 weight part with respect to 100 weight part of crosslinked pulp fibers of a pulp sheet.
The surfactant in the sanitary napkin is not attached to the absorbent body, but the amount used is 0.6 parts by weight with respect to 100 parts by weight of the cellulosic hydrophilic fiber in the absorbent body. It was 0.5 weight part with respect to 100 weight part of cellulosic hydrophilic fibers which added the cross-linked pulp fiber in the inside and the pulp fiber in the absorber.

[Comparative Example 1]
In Example 1, the same operation was performed except not spraying Mydoll 10, and the sanitary napkin was obtained.
[Comparative Example 2]
In Example 2, the same operation was performed except that the Mydoll 10 was not sprayed to obtain a sanitary napkin.

[Comparative Example 3]
The surface material (basis weight 25 g / m ² ) used in Example 2 was sprayed with a 1% water-diluted solution of a surfactant (decylglucoside, trade name “Mydol 10”) manufactured by Kao Corporation. 8 parts by weight of decylglucoside was attached to 100 parts by weight of the material. Thereafter, a pulp fiber / superabsorbent polymer mixed absorbent was prepared using the pulp fiber / superabsorbent polymer mixed sheet prepared in the same manner as in Example 2 except that the surfactant was not attached to the pulp fiber as an absorbent core. Thus, a sanitary napkin was prepared according to Example 2. The surfactant in the sanitary napkin was not attached to the absorber, but the amount used was 1.3 parts by weight with respect to 100 parts by weight of the cellulose-based hydrophilic fiber of the absorber. .

[Comparative Examples 4 to 6]
In the same manner as in Example 2, the surfactants of the type shown in Table 1 were adhered so as to have an adhesion amount shown in Table 1. Otherwise, a sanitary napkin was prepared in the same manner as in Example 2.

[Evaluation]
About each sanitary napkin of an Example and a comparative example, the rate of absorption, spot absorptivity, and liquid return amount were evaluated by the method shown below. The evaluation was shown by classifying each measured value into several categories according to the evaluation criteria described later. The evaluation results are shown in Table 1.
A sanitary napkin was placed horizontally, and an acrylic plate with an inlet having a diameter of 1 cm and a weight were placed thereon so that 5.0 g / cm ² (490 Pa) pressure was applied to the napkin. Next, 6 g of defibrinated horse blood (manufactured by Nippon Biotest Co., Ltd.) was injected from the injection port in about 1 second, and the time for which all of the defibrinated horse blood was absorbed was measured to determine the absorption rate. The state was maintained for 3 minutes after injection.
Next, the acrylic plate and the weight were removed, the liquid spreading area was measured, and spot absorptivity was judged. The measurement of the liquid spreading area will be described later.
Then, 10 sheets of absorbent paper (commercial tissue paper) with a basis weight of 30 g / m ^{2 and} a stack of 10 sheets (5 pairs of 2 sheets of tissue paper) are placed on the skin contact surface of the sanitary napkin. It was. Further, a weight was placed thereon so that the pressure was 6.6 × 10 ³ Pa, and pressure was applied for 2 minutes. The pressure is applied on the absorbent paper within 4 minutes after the liquid injection. After pressurization, 10 sheets of absorbent paper were taken out, the weight of the absorbent paper before and after pressurization was measured, and the amount of blood absorbed by the absorbent paper was determined. This value was defined as the amount of blood returned from the sanitary napkin.

[Measurement method of liquid spreading area]
Light source [Sunlight SL-230K2; manufactured by LPL Co., Ltd.], stand [Copy stand CS-5; manufactured by LPL Co., Ltd.], lens [24 mm / F2.8D Nikkor lens], CCD camera [(HV-37 Connection with lens by F-mount) and a video board [Spectra 3200; manufactured by Canopus Co., Ltd.]. In the measurement, it is necessary to obtain a correlation between the size displayed by the calibration operation and the pixel so that the area can be measured.
Next, an image of the liquid spread of the absorber core to be measured is captured. The captured image is binarized by the image analysis software NEW QUEBE (ver. 4.21) manufactured by NEXUS. An area is obtained from the binarized image and is defined as a diffusion area.

〔Evaluation criteria〕
1. Absorption rate A: 0.2 g / second or more ○: 0.17 g / second or more and less than 0.2 g / second ○ Δ: 0.14 g / second or more and less than 0.17 g / second Δ: 0.1 g / second or more and 0.14 g </ Sec. X: <0.1 g / sec.

2. Spot absorptivity ◎: Liquid spreading area is less than 27 cm 2 ○: Liquid spreading area is 27 cm 2 or more and less than 30 cm 2 ○ Δ: Liquid spreading area is 30 cm 2 or more and less than 32 cm 2 Δ: Liquid spreading area is 32 cm 2 or more and less than 35 cm 2 ×: Liquid spreading area is 35 cm 2 or more

3. Liquid return amount ◎: Less than 0.9 g ○: 0.9 g or more and less than 1.0 g ○ △: 1.0 g or more and less than 1.1 g △: 1.1 g or more and less than 1.2 g ×: 1.2 g or more

  As can be seen from Table 1, the sanitary napkins of the examples all have good absorption speed, liquid return amount, and spot absorbability, and the spot absorbability is particularly improved compared to the napkin of the comparative example.

FIG. 1 is a cross-sectional view schematically showing a cross section in the thickness direction of a sanitary napkin according to an embodiment of the present invention. FIG. 2A and FIG. 2B are plan views each showing an example of a second sheet (fiber layer) partially coated with a surfactant.

Explanation of symbols

1 Sanitary napkin (absorbent article)
2 Surface sheet 3 Leak-proof sheet 4 Absorber 41 Absorbent core 42 Fiber assembly 43 Super absorbent polymer 44,45 Absorbent paper (coated sheet)
5 Second sheet (intermediate layer)
20 Skin contact surface 30 Non-skin contact surface

Claims (10)

  An absorbent article comprising cellulosic hydrophilic fibers containing one or more surfactants selected from the group consisting of sugar alkyl ethers and sugar fatty acid esters in a portion other than the skin contact surface.   The absorbent article according to claim 1, wherein the surfactant has an HLB of 9 to 20.   The absorbent article according to claim 1 or 2, wherein the cellulosic hydrophilic fiber containing the surfactant is a fiber having a length of 3 to 30 mm and a diameter of 5 to 100 µm.   The absorbent article according to any one of claims 1 to 3, wherein an amount of the surfactant used is 0.1 to 1 part by weight with respect to 100 parts by weight of the cellulose-based hydrophilic fiber in the absorbent body.   A liquid-permeable surface sheet that forms a skin contact surface, a liquid-impermeable or water-repellent leak-proof sheet, and an absorber positioned between the two sheets. The absorbent article in any one of Claims 1-4 containing the cellulosic hydrophilic fiber to contain.   The absorbent comprises a cellulosic hydrophilic fiber containing the surfactant and a superabsorbent polymer, and the content of the superabsorbent polymer in the absorbent is the cellulosic hydrophilic fiber in the absorbent. The absorbent article according to claim 5, which is 20 to 120 parts by weight with respect to 100 parts by weight.   The absorbent article according to claim 5 or 6, wherein the absorbent body includes an absorbent core coated with a covering sheet, and the absorbent core includes cellulosic hydrophilic fibers containing the surfactant.   The absorbent article according to claim 5 or 6, wherein the absorbent body includes an absorbent core coated with a covering sheet, and the covering sheet includes cellulosic hydrophilic fibers containing the surfactant.   A liquid-permeable surface sheet that forms a skin contact surface, an absorbent body, and an intermediate layer disposed between the surface sheet and the absorbent body, the intermediate layer containing the surfactant The absorbent article in any one of Claims 1-8 containing a cellulosic hydrophilic fiber.   It has a fiber layer containing cellulosic hydrophilic fiber containing the surfactant, and a region where the surfactant is applied and a region where the surfactant is not applied in the planar direction of the fiber layer The absorptive article according to claim 1 mixed.

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