JP2647857B2 - Absorbent articles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disposable absorbent article excellent in usability, particularly to a disposable absorbent article such as a sanitary napkin and a disposable diaper.

[Conventional technology and its problems]

Conventionally, various studies have been conducted for the purpose of improving the performance of absorbent articles. In particular, research aimed at keeping the surface of the absorbent article after absorbing liquid as dry as possible so that the wearer does not suffer from skin diseases such as soreness and feels comfortable to use. Many results have been reported for.

For example, there is a technique for improving the drying characteristics of the surface by using a nonwoven fabric made of hydrophobic fibers as the surface material and reducing the diffusion retention of the liquid in the surface material.

However, as the constituent fibers of the nonwoven fabric, only fibers having a relatively small diameter can be used in order to impart sufficient strength to the nonwoven fabric, and it is not possible to arrange these fibers completely regularly in the nonwoven fabric. Impossible. In a nonwoven fabric in which such small-diameter fibers are irregularly arranged,
Inevitably, microscopic voids are formed, and these microscopic voids are continuous with each other. Since the liquid is very easily retained in the microscopic gap, when the liquid is discharged, a considerable amount of the liquid is diffused and retained in the surface material. Therefore, no matter how hydrophobic fibers are used, the drying characteristics of the surface of the nonwoven fabric are not sufficiently improved.

On the other hand, a film formed by embossing or the like on a film made of a hydrophobic resin, or a net-like sheet formed by combining a ribbon-shaped film made of a hydrophobic resin (these are combined into a perforated film ) Is used as a surface material to improve the drying characteristics of the surface.

Certainly, there are no microscopic voids in the perforated film,
Moreover, since the macroscopic apertures are completely isolated by the film resin, it is considered that the material is a material in which the retention of liquid diffusion is extremely small. However, when such a perforated film is used as a surface material directly in contact with the body surface, when the liquid is discharged, the liquid is not absorbed at all in portions other than the apertures of the perforated film. Liquid retention in between causes not only discomfort to the user, but also often causes skin disorders.

For this reason, attempts have been made to reduce the retention of liquid between the surface material and the body surface by increasing the aperture density of the perforated film.

However, there is a limit to the increase in the aperture density of the perforated film in terms of the strength of the perforated film. There are new problems such as difficulty in assembling into a sexual article and breaking of the surface material when worn.

Therefore, a technique using a net, which is an aggregate of filaments, as a surface material has been proposed.

In this net, since the macropores are closely adjacent to each other across the filament, the density of the pores is large, so that the liquid retention between the surface material and the body surface, which is a problem in the perforated film, does not occur. . However, in order to impart sufficient strength to the net, it is necessary to use a filament having a diameter larger than a certain level. But,
When such a large-diameter filament is used, it is absolutely inevitable that the texture is deteriorated due to an increase in roughness. Therefore, a net having sufficient strength as a surface material has a very poor texture, and is not very usable as a surface material. Incidentally, the poor texture of the net is largely attributable to the roughness due to the projections formed by the intersections of the filaments, in addition to the roughness due to the filament alone.

In view of this, a technique has been proposed for improving the smoothness of the net and improving the texture by performing physical processing such as calendaring. However, since the net with sufficiently improved smoothness has substantially the same structure as the perforated film, it has exactly the same disadvantages as the above-described perforated film. Eventually, this technology would be necessary to produce a perforated film, which is a material lacking suitability as a surface material, in two stages, that is, to first produce a net from raw resin and then produce a further perforated film. Not to mention that it is a meaningless technology.

As described above, none of the conventional surface materials has excellent drying characteristics on the surface, good touch and sufficient strength, and it was not possible to obtain an absorbent article having a good feeling in use.

[Means for solving the problem]

The present inventors have conducted intensive research to overcome such problems, and as a result, succeeded in creating an absorbent article using a completely new surface material composed of a composite of a film and a filament, and completed the present invention. I came to.

That is, the present invention relates to a hydrophobic porous sheet (hereinafter, referred to as composite) in which a group of filaments arranged in parallel with each other and a group of ribbon-shaped films arranged in parallel with each other are integrated. (Hereinafter referred to as a sheet) as a surface material.

Filaments as used in the present invention refer to single filaments (often referred to as monofilaments) or so-called spun fibers consisting of a number of fibers bundled together. Further, the film means a thin film material made of a synthetic resin, and the ribbon shape means a rectangular shape having a length substantially larger than the width.

In the composite sheet of the present invention, since the filament group or the film group is arranged in parallel,
The size and density of the holes can be freely controlled by the distance between the filaments or the film and the intersection angle between the filament and the film. Therefore, by setting them appropriately, a composite sheet having only macroscopic apertures without any microscopic voids can be obtained. Moreover, these macroscopic apertures are completely separated by filaments or films. Therefore, if the composite sheet of the present invention is used as a surface material, the suspension of liquid diffusion in the surface material, which is a problem in the case of a nonwoven fabric, does not occur.

And since the composite sheet has filaments, even a material having a large aperture density has a sufficient strength as a surface material of the absorbent article, so that the surface material and the body surface which became a problem in the case of a perforated film are used. There is no problem such as retention of the liquid between them and insufficient strength. In the composite sheet of the present invention, a filament having a much smaller diameter than that of a net can be used, and all the filaments are arranged in parallel and there is no intersection between the filaments. Has a good feeling for everyone without the roughness of the Internet.

Therefore, the composite sheet of the present invention is a material that can achieve the three performances of surface drying characteristics, touch and strength relatively easily and at a high level.

As the material of the filament forming the composite sheet of the present invention, any material may be used as long as it is hydrophobic. For example, polyolefins, copolymers of olefins with other monomers such as acrylates and vinyl acetate, polyesters, polyamides, polyacrylonitrile, synthetic resins alone such as cellulose acetate or blends thereof, and the like, Considering the properties, polyolefins, copolymers of olefins with other monomers, blends thereof, or polyamides are preferred.

As described above, the form of the filament may be either a monofilament or a spun fiber, but it can be said that the former is more cost-effective and more preferable. Further, the diameter of the filament can be freely determined within a range in which the composite sheet has both sufficient strength and good texture, but is generally preferably 0.02 to 0.5 mm, and more preferably 0.05 to 0.2 mm.

On the other hand, examples of the resin constituting the film include polyolefins, copolymers of olefins with other monomers such as acrylates and vinyl acetates, polyacrylates, and synthetic rubbers. Any material having an adhesive force and being hydrophobic may be used. The thickness of the film can also be freely determined within a range where the composite sheet has both sufficient strength and good texture, but is generally preferably 0.01 to 0.2 mm, more preferably 0.05 to 0.1 mm.

And the interval between the filaments or the film can be freely determined within a range in which the composite sheet has a sufficiently large aperture and strength, but is generally preferably 0.1 to 10 mm, more preferably 0.5 to 5 mm. preferable. The intervals need not be uniform (ie, the filaments and films are arranged at equal intervals) and may be irregular.

The crossing angle between the filament and the film can be freely determined within a range not equal to 0 °, that is, in a range where the filament and the film are not parallel. However, if the crossing angle is small, the strength in the direction perpendicular to the filament of the composite sheet is significantly reduced. Therefore, the angle is preferably 45 ° or more, and more preferably 80 to 90 °. In particular, it is preferable that the group of filaments and the group of films cross each other vertically.

Either heat bonding or adhesive bonding can be used to integrate the filament and the film.
Considering ease of production, thermal bonding is preferred.

The size of the aperture of the composite sheet of the present invention can be arbitrarily determined within a range in which no liquid is retained in the composite sheet and the composite sheet has a necessary covering property as a surface material. It is 0.02 to 30 mm ² , more preferably 0.1 to ³ mm ² .

The density of the pores can be arbitrarily determined as long as no liquid is retained between the composite sheet and the body surface and the composite sheet has a necessary covering property as a surface material. is a number / cm ^2, more preferably 15 to 3
It is 00 pieces / cm ² .

 The invention will be described in more detail below with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of the absorbent article of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG.
The absorbent article of the present invention is formed by sequentially laminating a liquid-impermeable leakproof material 1, a liquid-retaining absorber 2, and a composite sheet 3 as a liquid-permeable surface material. In FIG. 1, the direction of the filaments 4 of the composite sheet 3 is configured so as to coincide with the length direction of the absorbent article. However, if necessary, it may be configured in any other direction at all. In addition, the composite sheet 3 is usually configured as a single surface material, but two or more composite sheets may be used when the absorber 2 is easily deformed and a particularly high covering property is required for the surface material. It can also be configured as a surface material.

FIG. 3 is a plan view showing an example of the structure of the composite sheet of the present invention, in which a group of filaments 4 arranged in parallel with each other and a group of ribbon-shaped films 5 arranged in parallel with each other are integrated. Thus, the composite sheet 3 is formed.

On the other hand, FIG. 4 is a plan view showing an example of a particularly preferred structure of the composite sheet of the present invention, wherein the group of filaments 4 and the group of films 5 intersect perpendicularly to each other to form a composite sheet 3. Is formed.

Although it has already been mentioned that the film 5 is required to have a rectangular shape whose length is substantially larger than its width, it is not necessary to be strictly rectangular as can be seen from these figures. May have a partially curved shape, and as a result of melting of the film at the time of thermal bonding, adjacent films may be partially joined together, or the films may be partially joined by an adhesive. It may be crosslinked. Further, one ribbon-like film may be divided into a plurality of ribbons at a certain portion.

〔Example〕

Hereinafter, the usefulness of the present invention will be described with reference to specific examples, but the present invention is not limited to these examples.

Examples 1 to 16 and Comparative Examples 1 to 7 The composition and physical properties of the surface material according to the present invention, the composition and physical properties of the surface material used as being outside the scope of the present invention, and the absorbency using these surface materials Table 1 shows the performance of the articles.

In Examples 7 to 13, a commercially available composite sheet called FFB (manufactured by Hagiwara Industry Co., Ltd.) was used as a surface material. In Examples 1 to 6 and 14 to 16, a nylon filament collected from the FFB and Evaflex (manufactured by Mitsui Polychemicals Co., Ltd.) were extruded into a film, which was then cut with a cutter and cut into ribbons. The shape was used.

In Examples 1 to 3 and Examples 7 to 13, the intersection of the filament and the film was heat-pressed with a soldering iron to perform thermal bonding. In Examples 4 to 6 and 14 to 16, the intersection of the filament and the film was bonded using Araldite (Nichiban Co., Ltd.) which is an epoxy adhesive.

In Comparative Example 1, a commercially available spunbonded nonwoven fabric, IEL (manufactured by Asahi Kasei Corporation) was used as a surface material. Further, in Comparative Example 2, a nonwoven fabric was prepared by forming a web using ES fibers (manufactured by Chisso Corporation), which is a polyethylene-polypropylene conjugate fiber, using a miniature card, and subjecting the web to hot air fusion to mutually fuse the fibers. This was used as a surface material. In Comparative Examples 3 and 4, Mirason (manufactured by Mitsui Polychemicals, Inc.) was formed into a film by an extruder, and a perforated film was produced by punching predetermined holes using a punch, and this was used as a surface material. .
In Comparative Example 5, Warif (manufactured by Nisseki Koki Co., Ltd.), which is a net-like sheet made of a ribbon-like film, was used as a surface material. In Comparative Examples 6 and 7, each of Netron (manufactured by Mitsui Petrochemicals Co., Ltd.) and Net 909 (Smith & Nephew Co., Ltd.)
Commercially available net was used as a surface material.

Hereinafter, a method of measuring the configuration and physical properties of the surface material will be described.

(1) Intersection angle between filament and film: Using a stereomicroscope, an enlarged photograph of the opening surface viewed from the vertical direction was taken, and as shown in FIG. 5, the intersection angle θ between the filament 4 and the film 5 was determined using a protractor. It was measured.

(2) Size of the hole: Using a stereoscopic microscope, an enlarged photograph of the hole surface viewed from the vertical direction was taken, and the size a of the hole on the photograph was measured using a planimeter. ) Was used to calculate the size A of the full-sized hole.

A (mm ² ) = a (mm ² ) / x ² (1) x: Magnification of the photograph relative to the actual product (3) Density of apertures: Measured by counting the number of holes per 1 cm ^{2 of} surface material. .

(4) Strength: The surface material was cut into rectangles of 50 mm and 170 mm in length and width, respectively, and used as test pieces. Then, the maximum load indicated when the test piece was tensile-ruptured was measured using a tensile tester, and this was defined as the strength.

(5) Touch: The feel when the surface material was lightly stroked with the back of the hand was classified into the following three ranks.

：: There is no roughness at all.

Δ: Roughness is slightly observed.

×: The texture is remarkably rough, and is unsuitable as a surface material of an absorbent article.

(6) Remaining liquid: Remove the surface material of commercially available Laurier (manufactured by Kao Corporation),
And an absorbent article assumes samples constituting each surface material was precisely weighed weight W ₁ instead. After absorbing the test liquid into the sample and precisely weighed W ₂ removes surface material. The difference W ₂ −W ₁ between the weights of the surface material before and after the absorption was defined as liquid residue. In general, it is desirable that the value of the liquid residue is 0.15 g or less so that the smaller the value of the liquid residue, the more excellent the drying characteristics of the surface.

[Effects of the Invention] As shown in Examples 1 to 16, the surface material according to the present invention has high strength and good touch, and also has a small amount of liquid residue and excellent surface drying characteristics, so that the feeling of use is extremely low. A good absorbent article can be obtained. In particular, the intersection angle between the filament and the film is 80-90 °, and the size of the aperture is 0.1-3 mm ²
In Examples 7 to 14 using a surface material having an aperture density of 15 to 300 holes / cm ² and bonded by thermal bonding, an excellent absorbent article having excellent strength was obtained. give.

In Comparative Examples 1 and 2, a nonwoven fabric made of a hydrophobic fiber is used as the surface material, and there is no problem in strength and touch, but a large amount of liquid remains and the surface has poor drying characteristics. This is because there are many fine voids in the nonwoven fabric as described above.

In Comparative Examples 3 to 5, a hydrophobic porous film is used as a surface material. In the case of Comparative Example 3, the hole density of the perforated film was low, the liquid residue was large, and the drying characteristics of the surface were poor. This is because the liquid is not absorbed at all in portions other than the holes as described above. On the other hand, in the case of Comparative Examples 4 and 5, the pore density of the perforated film was high and the liquid residue was considerably reduced, but the strength was also significantly reduced. Comparative Example 6
In Nos. 7 and 7, a hydrophobic net is used as a surface material, but the texture is unacceptably bad. From these facts, it is understood that the perforated film and the net are extremely inappropriate materials as the surface material of the absorbent article.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of the absorbent article of the present invention,
2 is a cross-sectional view taken along the line AA of FIG. 1, FIGS. 3 and 4 are plan views showing an embodiment of the surface material of the present invention, and FIG. 5 is a method for measuring the intersection angle between the filament and the film. FIG. 1: Leakproof material, 2: Absorber 3: Composite sheet, 4: Filament 5: Film

Claims (3)

(57) [Claims] 1. A hydrophobic porous sheet comprising a group of filaments arranged in parallel with each other and a group of ribbon-shaped films arranged in parallel with each other is used as a surface material. An absorbent article characterized by the above. 2. The absorbent article according to claim 1, wherein the group of filaments and the group of films intersect perpendicularly with each other. 3. The porous sheet according to claim 1, wherein the size of the opening is 0.1 to ³ mm ^2.
, And the and the absorbent article of the range first claim of claims aperture density of 15 to 300 pieces / cm ^2.