JPH1080445A - Front surface sheet of absorptive article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve various properties, such as dry feel, by constituting a front surface sheet of specific number of sheets of nonwoven fabrics having many apertures and joining these nonwoven fabrics to each other at the peripheral edges of these apertures. SOLUTION: The front surface sheet 1 of the absorptive articles comprises >=2 layers the nonwoven fabrics 7, 7' having the many apertures 6, 6.... The nonwoven fabrics produced by a card method are usable as the nonwoven fabrics 7, 7' and more particularly there are no limitations. While the thickness and basis weight of the nonwoven fabrics are not particularly limited, the thickness under loading about 0.5g/cm<2> is preferably about 0.4 to 1.5mm in terms of hand and workability. The nonwoven fabric 7 of the upper layer and the nonwoven fabrics 7' of the lower layer are joined to each other at the peripheral edges of the respective apertures 6 and are not joined exclusive of these peripheral edges. As a result, liquid hardly migrates exclusive of the peripheral edges of the apertures 6 and the residues 9, 9' are generated respectively. The impression of the decreased liquid residues is eventually visually given. The soft fell, etc., inherent to the nonwoven fabrics remain in the parts which are not joined. The hand, etc., are improved as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface sheet for absorbent articles such as sanitary napkins and disposable diapers, and more particularly, to a dry sheet and a soft sheet or a soft and soft texture. The present invention relates to a surface sheet of an absorbent article in which various physical properties required for the surface sheet of the absorbent article are improved, and in particular, the concealing property of the absorbed liquid is improved.

[0002]

2. Description of the Related Art
Perforated films or nonwoven fabrics have often been used as surface sheets for absorbent articles such as sanitary napkins and disposable diapers. When a perforated film is used as a surface sheet, an aperture is provided on the surface of a plastic film as disclosed in Japanese Patent Publication No. 57-17081, etc.
A method of absorbing blood and urine through the opening is employed. However, the perforated film has a sticky feeling peculiar to the film, and since the skin contact surface other than the perforated portion has no air permeability at all, when used as a surface sheet of an absorbent article, Gives discomfort like clinging to the skin.

On the other hand, a nonwoven fabric type topsheet is disclosed in Japanese Utility Model Application Laid-Open No. 53-5010 in order to reduce the feeling of body fluid wetting on the skin of the user and to enhance the permeability of body fluid.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. 4 (1994) -204, there is known a topsheet made of a hydrophobic nonwoven fabric having a large number of regularly arranged openings. However, such a topsheet has the drawbacks that migration of bodily fluids to the absorber is unlikely to occur, that even when the amount of absorption is low, that leakage tends to occur, and that wetness and stickiness are easily felt.

There is also known a surface sheet in which openings are formed in a nonwoven fabric made of hydrophilic fibers or a nonwoven fabric subjected to a hydrophilic treatment. However, such a topsheet has a problem that the topsheet is clinged to the skin and has a sticky feeling because a portion other than the opening is a planar structure, so that a considerable portion of the surface comes into contact with the skin. For this reason, there is a demand for a surface sheet that further reduces the contact with the skin and improves the air permeability between the skin and the surface sheet.

Further, Japanese Patent Application Laid-Open No. 4-152945 discloses a nonwoven fabric having three-dimensional openings. However, such a nonwoven fabric has the same problem as the surface sheet in which the hydrophobic nonwoven fabric is provided with openings, since the portion other than the openings is a planar structure. In addition, since such a nonwoven fabric is composed of fine fibers, the density of the fibers is high, and when used for a long time, the liquid enters between the fibers and the stickiness is more easily felt. Further, in order to maintain the shape of the three-dimensional aperture against pressure, it is necessary to increase the density of fibers and the strength of the nonwoven fabric. As a result, such nonwoven fabrics generally have a rough feel. Tend to have.

Accordingly, an object of the present invention is to provide a surface sheet of an absorbent article in which various physical properties required for the surface sheet of the absorbent article, such as a dry feeling and a feeling such as softness and softness, are improved. It is in. Another object of the present invention is to provide a surface sheet of an absorbent article in which the concealing property of the absorbed liquid is particularly improved.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have achieved the above object by forming the topsheet from two or more layers of nonwoven fabric and joining the nonwoven fabrics to each other at the periphery of the opening. It has been found that a surface sheet of an absorbent article that can be obtained is obtained.

[0008] The present invention has been made based on the above findings, and in the surface sheet of an absorbent article comprising a nonwoven fabric having a large number of openings, the surface sheet has at least 2 sheets.
The object has been attained by providing a surface sheet of an absorbent article, comprising a nonwoven fabric of a layer, wherein the nonwoven fabrics are joined to each other at a peripheral portion of the opening.

[0009]

The surface sheet of the absorbent article of the present invention has a structure in which two or more nonwoven fabrics are laminated, so that the absorbed liquid can be concealed from the outside and the visual dryness can be improved. . In addition, since the non-woven fabric's original properties are not impaired in the portions other than the peripheral portion of the opening in each nonwoven fabric, the above-mentioned topsheet is excellent in texture such as soft feeling and softness while being a laminate of two or more layers. It will be.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a surface sheet of an absorbent article of the present invention (hereinafter sometimes simply referred to as "surface sheet").
The preferred embodiment will be described in detail with reference to the drawings. Here, FIG. 1 is an enlarged plan view showing a main part of one embodiment of the topsheet of the absorbent article of the present invention,
2 is a partial cross-sectional view along the line AA in FIG. 1, FIG. 3 is a perspective view of the topsheet of the embodiment shown in FIG. 1, and FIG. 4 is an enlarged view of a main part of FIG. It is.

As shown in FIGS. 1 to 3, the topsheet 1 of this embodiment has a large number of openings 6, 6,... And is composed of two layers of nonwoven fabrics 7, 7 '. As the nonwoven fabrics 7 and 7 ′, conventionally known nonwoven fabrics can be used without any particular limitation. For example, nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric manufactured by the card method,
Various non-woven fabrics such as spun lace non-woven fabric and needle-punched non-woven fabric can be appropriately selected according to the purpose and application. There is no particular limitation on the means for bonding the fibers in these nonwoven fabrics. For example, bonding by a binder or bonding by heat fusion can be used. Further, instead of the bonding of the fibers, mechanical entanglement of the fibers such as a spunlace nonwoven fabric may be used. In order to remarkably realize the desired properties, particularly improved softness and dryness, the heat-fusible fiber web obtained by the card method is suction-heat-bonded as the nonwoven fabric, without undergoing strong compression. A nonwoven sheet is most preferably used. The upper nonwoven fabric 7 and the lower nonwoven fabric 7 'may be the same or different.

In the present specification, the term "nonwoven fabric" means not only a single nonwoven fabric but also nonwoven fabrics, a nonwoven fabric and a film,
It includes various non-perforated sheets obtained by combining and integrating nonwoven fabric and paper or nonwoven fabric and other materials.

The nonwoven fabrics 7, 7 'have an original thickness (that is,
The thickness of the nonwoven fabric before the openings are formed) and the basis weight are not particularly limited, but the thickness under a load of 0.5 g / cm ² is 0.4 to 0.4 g / cm ² from the viewpoint of texture and workability. 1.5mm
Is preferably 0.4 to 1.0 mm, more preferably 0.5 to 0.7 mm. The basis weight is 1 for each of texture, uneven formation and workability.
It is preferably from 5 to 45 g / m ^2, more preferably from 15 to 3 g / m ^2.
5 g / cm ² . The thickness and basis weight of the upper nonwoven fabric 7 and the thickness and basis weight of the lower nonwoven fabric 7 ′ may be the same or different.

The fibers used in the nonwoven fabrics 7 and 7 'include, for example, synthetic fibers such as polyesters such as polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) and polyamides such as nylon, and rayon. And regenerated cellulose fibers such as cupra, and natural fibers such as cotton, but are not limited thereto. Also, composite fibers such as a core-sheath fiber, a side-by-side fiber, a split fiber and the like, in which a fiber having a high melting point is used as a core and a fiber having a low melting point is used as a sheath, are preferably used. One or more of these fibers can be used. These fibers may be blended with a predetermined amount of a pigment such as TiO _{2 as} needed to improve the concealability of the topsheet. However, the topsheet of the present embodiment has two or more layers of nonwoven fabric as described above. , The concealing property does not decrease even if the amount of TiO ₂ or the like is reduced as compared with the conventional case. The fiber diameter of these fibers is not particularly limited, but is preferably from 0.1 to 6.0 denier, and more preferably from 1 to 4 denier. If the fiber diameter is less than 0.1 denier, the distance between the fibers becomes small, and liquid may remain on the topsheet due to the capillary force, and if the fiber diameter exceeds 6.0 denier, the concealing property may deteriorate. Therefore, it is preferable to be within the above range. The fibers constituting the upper nonwoven fabric 7 and the fibers constituting the lower nonwoven fabric 7 'may be the same or different.

As shown in FIGS. 2 and 3, the upper nonwoven fabric 7 and the lower nonwoven fabric 7 ′ are joined to each other at the periphery of the opening 6. In addition, the nonwoven fabrics 7 and 7 'are not joined at portions other than the peripheral portion. Therefore, as shown in FIG. 4, the upper nonwoven fabric 7 and the lower nonwoven fabric 7 ′ are not integrated with each other at portions other than the peripheral portion of the opening 6 in the topsheet of the present embodiment, and are separated from each other. Is composed. As a result, liquid transfer from the upper non-woven fabric 7 to the lower non-woven fabric 7 ′ is less likely to occur, and liquid residues 9, 9 ′ are generated in different portions between the upper non-woven fabric 7 and the lower non-woven fabric 7 ′. Gives a small impression visually. In addition, since the liquid remaining in the lower layer looks faint as if it has passed through the screen, the concealability of the entire topsheet is improved. Further, in the portion where the upper nonwoven fabric 7 and the lower nonwoven fabric 7 'are not joined, the texture such as softness and softness which the nonwoven fabric originally has is not impaired, so that the texture of the topsheet itself is also excellent. It will be.

On the other hand, in the peripheral portion of the opening 6, the upper nonwoven fabric 7 and the lower nonwoven fabric 7 'are bonded to each other, so that the density of fibers is higher than that of the portion other than the peripheral portion. ing. That is, there is a gradient in the existing density of the fibers in one surface sheet. Since the fiber abundance affects the capillary force, a gradient in the fiber abundance means a gradient in the capillary force. Due to the gradient of the capillary force, a portion having a low fiber existence density, that is, a portion where the upper nonwoven fabric 7 and the lower nonwoven fabric 7 ′ are not joined to a portion having a high fiber existence density, that is, the opening 6. The transfer of the liquid to the peripheral portion is promoted, the absorbing power of the liquid is improved, and the remaining amount of the liquid in the topsheet is reduced. In addition, since the nonwoven fabrics of the respective layers are joined to each other at the periphery of the opening 6, as shown in FIG. 1, the fibers constituting the nonwoven fabric do not jump out of the opening 6, and the outline of the opening 6 is It becomes clear and gives a good impression to the user. In addition, by forming openings through a plurality of nonwoven fabric layers, the shape and size of each opening 6 are made uniform as compared with when a single-layer nonwoven fabric is opened, and the impression of the openings is further improved. . In the present specification, the term "joined to each other" means that the fibers constituting each nonwoven fabric are mechanically entangled, thermally softened and melted, or bonded by a binder or the like, so that It means that the nonwoven fabric is integrated. Therefore, the topsheet of the present embodiment is
Two types of fiber webs are laminated, and the fiber between each web is mechanically entangled, thermally softened / melted, or bonded by a binder or the like to form an opening in the nonwoven fabric obtained by integration. It is different from those provided (for example, the surface sheets of Comparative Examples 2 and 3 described later).

In the topsheet 1 of the present embodiment, the lower nonwoven fabric 7 'has a smaller fiber diameter (fineness) of constituent fibers in the lower nonwoven fabric 7 than in the upper nonwoven fabric 7. That is, a gradient is provided in the fiber diameter of the constituent fibers in the cross-sectional direction of the topsheet. Such a gradient in fiber diameter also causes a gradient in capillary force. This, together with the capillary force appearing at the peripheral portion of the opening 6, further enhances the liquid absorbing ability, and further effectively prevents the liquid remaining and the liquid from returning back, thereby reducing the dryness of the surface. Get higher. The difference in fiber diameter (fineness) between adjacent nonwoven fabrics is 1 to 1 in terms of improving the liquid absorption capacity, preventing the liquid from remaining, and preventing the liquid from returning.
It is preferably 4 denier, more preferably 2 to 3 denier.

As shown in FIGS. 2 and 3, the opening 6 is formed by being surrounded by nonwoven fabrics 7, 7 'extending from the front surface 8A of the topsheet 1 toward the back surface 8B. The inner wall 10 of the opening 6 is formed as a continuous surface from the surface 8A. That is, the opening 6 is a three-dimensional opening. As a mode of the three-dimensional opening, for example, the opening in which the nonwoven fabric surrounding the opening 6 is cylindrical, or the diameter of the opening 6 gradually increases from the front surface 8A toward the back surface 8B. As shown in FIGS. 2 and 3, an inverted conical opening in which the diameter of the opening 6 gradually decreases from the front surface 8A toward the back surface 8B is shown. preferable.

The shape of the opening 6 is not particularly limited, and may be, for example, an elliptical, triangular or quadrangular opening. However, as shown in FIG. This is preferable because the soft feeling of the sheet 1 can be improved.

The openings 6 can be formed, for example, in accordance with a preferred method of manufacturing a topsheet of the present invention described later.

When the topsheet 1 of this embodiment is incorporated into an absorbent article, the surface 8A is used as a surface that comes into contact with the skin.

As shown in FIG. 2, the space between adjacent openings 6
Is convexly curved so as to have a top portion 5. Here, the apex refers to the highest position between adjacent openings. In the topsheet 1 of the present embodiment,
As shown in FIG. 3, it is preferable that a plurality of the tops are continuously connected to form a ridge. Top sheet 1 shown in FIG.
In the above, a plurality of the tops are continuously connected substantially linearly to form a multi-row ridge portion 2, 2,..., A groove portion 4 is formed between the adjacent ridge portions 2, 2, and the ridge portion is formed. 2 and the groove 4
Are alternately arranged so as not to have a plane portion. The ridge portion 2 is convexly curved and the groove portion 4 is concavely curved, and the groove portion 4 has a large number of openings 6, 6,... Arranged at predetermined intervals. ing. By forming the ridge portion 2 and the groove portion 4 in this manner, the bending characteristics (for example, bulk softness, etc.) in a direction parallel to the ridge portion 2 and the groove portion 4 and in a direction perpendicular thereto are different. It is preferable because it can impart anisotropy and can further improve the fit and texture of the topsheet 1 to the body.

There are no particular restrictions on the arrangement pattern of the openings 6, 6,... In the groove portion 4. For example, a staggered arrangement pattern as shown in FIG. 1 can be used. In this case, the interval N between the openings 6 and 6 along the groove 4 is 0.4 to 4
It is preferably 0 mm, more preferably 1.5 to 8 mm. If the interval N is less than 0.4 mm, the perimeter of the opening 6 becomes small, and the periphery of the opening 6 may not be firmly formed.
If it exceeds 0 mm, the existence of the openings 6 becomes coarse and the liquid permeability may decrease, so that it is preferable to be within the above range.

As shown in FIGS. 1 to 3, the ridges 2 and the grooves 4 are alternately arranged, and the grooves 4 are formed by a continuous surface from the ridges 2. As shown in FIG. 2, the interval L between the adjacent ridges 2 is 1.0 to 6.0 m.
m, and more preferably 1.7 to 3.7 mm. Further, the distance M between the adjacent grooves 4
Is also preferably 1.0 to 6.0 mm,
More preferably, it is 1.7 to 3.7 mm.

In the topsheet 1 of the present embodiment, the direction of the ridges 2 and the grooves 4 does not need to match the longitudinal direction or the transverse direction of the absorbent article in which the topsheet 1 of the present embodiment is used. . For example, even if the direction of the ridge portion 2 and the groove portion 4 is the longitudinal direction of the absorbent article, there is no problem at all, and it can be suitably used. Similarly, even if the direction perpendicular to the ridge portion 2 and the groove portion 4 is the longitudinal direction of the absorbent article, there is no problem at all and it can be used preferably.

The ridge portion 2 and the groove portion 4 may or may not match the machine direction at the time of manufacturing the nonwoven fabrics 7 and 7 ′ as raw materials.

In the topsheet 1 of the present embodiment, the height of the top 5 between the openings 6 adjacent in one direction (for example, the height of the position P in FIG. 1) and the direction perpendicular to the direction In different directions, the height of the top 5 between the openings 6 adjacent to each other (for example, the height at the position Q in FIG. 1) is different. By providing a gradient at the height of the top, the direction of absorption and diffusion of the liquid can be controlled. For example, if the liquid is to be diffused in a particular direction, the height of the top between adjacent openings in that direction is set to the height of the top between adjacent openings in a direction perpendicular to that direction. It should just be higher than it. Furthermore, by using such a gradient of the height of the top portion and the ridge portion, the direction of absorption and diffusion of the liquid can be more effectively controlled. For example, the tops are continuously connected in a specific direction to form a ridge, and the height of the ridge is higher than the height of the top between the openings adjacent to each other in a direction perpendicular to the direction. When the height is increased, the liquid easily moves along the ridge portion, and the liquid movement in a direction perpendicular to the direction is more effectively suppressed.

In the topsheet 1 of this embodiment, as shown in FIG. 2, the openings 6 (preferably circular or oval) are formed.
It is preferable that the diameter d of the peripheral edge at the lower end is 0.5 to 2.0 mm. If the diameter d is less than 0.5 mm, the effect of sucking the liquid existing on the surface of the topsheet 1 and the vicinity thereof and rapidly leading the liquid to the absorber may be difficult to be exhibited. If it exceeds, the concealing property of the absorbed liquid may be reduced, and the distance between the fibers at the lower peripheral edge of the opening is clogged, and the lower peripheral edge has a shape close to the film, so that the liquid is Since there is a case where the passage space cannot be obtained and the passage of the liquid becomes difficult, it is preferable to be within the above range. More preferably, the diameter d is 0.7 to 1.5 mm.

In the topsheet 1 of the present embodiment,
The thickness under a load of 0.5 g / cm ² is preferably 0.6 mm or more. The thickness under a load of 0.5 g / cm ² substantially corresponds to the thickness of the topsheet when lightly touching the topsheet. When the thickness is 0.6 mm or more, a surface sheet having a bulky and improved soft feeling can be obtained. If the basis weight of the top sheet is increased (for example, 60 to 100 g / m ² ), the thickness becomes 0.6 m.
Although it is easy to set it to m or more, in that case, the texture may be deteriorated. On the other hand, in the topsheet 1 of the present embodiment, even when the basis weight is not large, the thickness is 0.6 mm due to the three-dimensional action of the openings and the tops located between the openings. The above is easy. The thickness is preferably from 0.6 to 2.0 mm, more preferably from 0.6 to 1.5 mm.

The total basis weight of the topsheet 1 of the present embodiment is 20 to 70 g / m2 in view of workability and texture.
² , and more preferably 25 to 60 g / m ² .

In the topsheet 1 of the present embodiment, it is important to enhance the ability to absorb the liquid from the openings 6. For this purpose, the opening ratio of the topsheet 1 of this embodiment is 5%.
Or more, more preferably 7% or more, even more preferably 10 to 20%. If the opening ratio is less than 5%, the amount of liquid passing through the opening 6 decreases, and the liquid may easily remain on the topsheet 1. In addition, the said opening ratio is a value calculated | required by dividing the area of the opening formed when projecting the topsheet 1 of this embodiment from the front surface 8A to the back surface 8B by the area of the topsheet. . The specific measuring method will be described later.

Although the topsheet of the present invention has been described based on the preferred embodiment, the topsheet of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. is there. For example, the nonwoven fabric constituting the topsheet may have three or more layers. Further, the openings need not be provided on the entire surface of the topsheet, but may be provided only in a predetermined area. The arrangement of the openings is not limited to the staggered arrangement, but may be a lattice arrangement or another arrangement. Further, in order to further improve the effect of improving the liquid absorption capacity and preventing the liquid from returning, it is preferable that the lower layer nonwoven fabric has higher hydrophilicity than the upper layer nonwoven fabric. Further, in each of the nonwoven fabrics constituting the topsheet, the fiber diameter on the lower side may be smaller than that on the upper side.

Next, preferred examples of the absorbent article provided with the topsheet 1 of the present embodiment will be described in detail with reference to the drawings.
Here, FIG. 5 is a perspective view showing a sanitary napkin as an absorbent article provided with the topsheet of the present embodiment.

The sanitary napkin 14 shown in FIG. 5 includes the topsheet 1, the liquid-impermeable backsheet (not shown), and the absorber (not shown) of the present embodiment. The absorbent body is covered with the backsheet except for the surface of the sanitary napkin 14 which is in contact with the skin. Further, the surface of the absorbent body that comes into contact with the skin among the surfaces of the sanitary napkin 14 is covered with the topsheet 1. Further, the topsheet 1 covers the entire absorber. In the sanitary napkin 14, the description of the conventional sanitary napkin is appropriately applied to the points that are not described in detail.

Since the sanitary napkin 14 has the topsheet 1 of the present embodiment, the sanitary napkin is excellent in concealing property of absorbed liquid, feeling, liquid permeation / absorbing property, and liquid remaining preventing property. It will be.

That is, first, the sanitary napkin 14 is composed of a plurality of nonwoven fabrics constituting the topsheet, so that the sanitary napkin 14 has a high concealing property, and the absorbed liquid is hardly visible from the outside, and the Dry feeling is improved. Secondly, since the non-woven fabric is not bonded to each other, the original soft feel of the nonwoven fabric is not impaired, so that a comfortable wearing feeling can be obtained. Third, in the surface sheet where the nonwoven fabrics are bonded to each other, the density of the fibers is higher than that of the other parts, and the capillary force has a gradient. Is promoted, the absorbing power of the liquid is improved, and the remaining amount of the liquid in the topsheet is reduced.

As described above, the sanitary napkin has been described as an example of the absorbent article using the topsheet of the present embodiment. However, it goes without saying that the absorbent article using the topsheet is not limited to this. The present invention can be applied to other absorbent articles such as a surface sheet of a hygiene pad, a nursing pad, a disposable diaper, and the like without any particular limitation.

Next, a preferred method for producing the topsheet of the present embodiment will be described in detail. The topsheet of this embodiment can be manufactured by stacking two nonwoven fabrics and mechanically opening the holes. More specifically, after laminating two nonwoven fabrics unwound from a raw roll, the laminated nonwoven fabric is interposed between a first pressing die and a second pressing die to have the above structure. Topsheets can be manufactured. The first pressing die has a number of pyramidal or conical convex pins arranged in a row along the transport direction of the nonwoven fabric, and is configured from a pin roll in which the rows are arranged in multiple rows. The second pressing die is composed of a ridge roll having a ridge fitted between the multi-row convex pins in the first first pressing die.

In the above manufacturing method, the pin rolls are arranged such that the protruding pins are arranged in rows along the transport direction of the nonwoven fabric, and the rows are arranged in multiple rows. On the other hand, in the ridge roll, the ridge portion is fitted between rows of the convex pins of the pin roll. As a result, the top portion of the topsheet of the present embodiment is easily formed by the ridge portion of the ridge roll, and the opening is formed by pressing the convex pin of the pin roll against the nonwoven fabric. It is formed. In this case, the pin roll is
C., the periphery of the opening is partially softened or partially melted, and the nonwoven fabrics are joined to each other at the periphery. Before introducing the laminated non-woven fabric between the rolls, in order to enhance the bonding property of each non-woven fabric,
For example, hot air (for example, 6
(0 to 260 ° C.) or a preheat treatment known to those skilled in the art, such as winding the laminated nonwoven fabric around a preheat roll (for example, 60 to 260 ° C.).

Next, the topsheet of the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples.

[Examples 1 to 7 and Comparative Examples 1 to 4] A suction heat-bonded nonwoven fabric obtained from the fibers shown in Table 1 was used as a raw material (except for the lower nonwoven fabric of Example 3), and the above-described method was used. Opening and joining (pin roll temperature: 125
° C) to produce a topsheet shown in Figs. Table 2 shows various physical properties of the topsheet. In addition, the measuring method of the physical property value in Table 2 is as follows.

<Aperture Diameter> Using an image analyzer “Excel” manufactured by Nippon Avionics Co., Ltd., the above-mentioned top sheet pasted on a black mount was input as an image, and a black-and-white binarization process was performed on the screen. The portion corresponds to the opening. The diameter of the circular portion is calculated from the area of the white portion as a circular shape, and this is defined as the aperture diameter.

<Pore Opening Ratio> Using the image analyzer “Excel” manufactured by Nippon Avionics Co., Ltd., the above-mentioned top sheet pasted on a black mount is input as an image and the black-and-white area ratio on the screen is calculated. At this time, since the white area on the screen corresponds to the aperture, the white area with respect to the entire screen area is defined as the aperture ratio (%).

<Thickness of surface sheet under a load of 0.5 g / cm ² > KES compression tester (K-Tech K.K.)
Using ES FB-3), a compression property test is performed on the above surface sheet in a normal test mode up to 50 g / cm ² , and the thickness (mm) under a load of 0.5 g / cm ^{2 is} read from the chart.

<Relative reflectance> Assuming that menstrual blood was absorbed by the topsheets obtained in Examples and Comparative Examples, the topsheet was placed so as to cover the surface of the red standard plate, and how much red was blocked. Then, whether the color was approaching white was evaluated by relative reflectance. The larger the relative reflectance is, the higher the concealing property is. The relative reflectance was measured under the following conditions and calculated from the following equation. Measuring device Nippon Denshoku Industries Co., Ltd. color difference meter “SZ- $ 80” Measurement conditions Light source: C / 2 Number of measurements: 5 Measurement wavelength: 500 nm

[0046]

(Equation 1)

<Impression after Liquid Absorption and Impression of Opening> Using the topsheets obtained in Examples and Comparative Examples, a sanitary napkin 14 shown in FIG. 5 is produced. After attaching the sanitary napkin 14 to the female waist model shown in FIG. 6 as shown in FIG. 7 and further wearing shorts, 100 steps / min (50 m / min)
At a walking speed of 5 minutes and 30 seconds. Meanwhile tube 8
1.5 g of defibrillated horse blood 1 minute after walking through 1
After 5 seconds, a total of 3 g of 1.5 g is injected. For the sanitary napkin after walking, make the absorbed liquid less visible.
No evaluation was performed by 0 persons, and this was regarded as an impression after the liquid was absorbed.
Separately from this, the completed state of the opening was evaluated for the topsheet in a state where the liquid was not absorbed, and this was used as an impression of the opening. These evaluations were performed on the basis of the following four grades, and the average value of 10 persons was taken. Evaluation criteria Very good: ◎ Good: ○ Normal: △ Bad: ×

[0048]

[Table 1]

[0049]

[Table 2]

As is evident from the results shown in Table 2, the surface sheets of the present invention (Examples 1 to 7) have the same level of liquid absorption compared to the surface sheets obtained in Comparative Examples. The impression after the liquid absorption and the impression of the opening are good, and it can be seen that the concealing property is high.

[0051]

According to the topsheet of the present invention, various physical properties required for the topsheet of the absorbent article, such as a dry feeling and a feeling such as softness and softness, are improved. Further, according to the topsheet of the present invention, the concealing property of the absorbed liquid is particularly improved, and the visual dry feeling is also improved.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view showing a main part of one embodiment of a topsheet of an absorbent article of the present invention.

FIG. 2 is a partial sectional view taken along line AA in FIG.

FIG. 3 is a perspective view of the topsheet of the embodiment shown in FIG. 1;

FIG. 4 is an enlarged view of a main part of FIG. 2;

FIG. 5 is a perspective view showing a sanitary napkin as an absorbent article provided with the topsheet of the embodiment shown in FIGS.

FIG. 6 is a diagram showing a female waist model.

FIG. 7 is a view showing a state in which a sanitary napkin is attached to a female waist model.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top sheet 2 Ridge part 4 Groove part 5 Top part 6 Opening 8A Front side 8B Back side 14 Sanitary napkin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiro Komori 2606 Akabane, Kaimachi, Haga-gun, Tochigi Pref.

Claims (4)

[Claims] 1. A topsheet of an absorbent article comprising a nonwoven fabric having a large number of apertures, wherein the topsheet is composed of at least two layers of nonwoven fabric, and each nonwoven fabric is joined to each other at the periphery of the aperture. A surface sheet of an absorbent article characterized by the above-mentioned. 2. The surface sheet of an absorbent article according to claim 1, wherein the nonwoven fabric located in a lower layer has a smaller fiber diameter of constituent fibers than the nonwoven fabric located in an upper layer. 3. The opening is formed so as to be surrounded by the nonwoven fabric extending from the front surface to the back surface of the topsheet, and the opening is curved convexly so as to have a top portion between the adjacent openings. The topsheet of the absorbent article according to claim 1, wherein the topsheet is made. 4. The surface sheet has a large number of ridges and grooves alternately arranged so as not to have a flat portion, wherein the ridges are convexly curved and the grooves are concavely curved. The topsheet of an absorbent article according to any one of claims 1 to 3, wherein the groove has a large number of the openings arranged at intervals.