JPH01158954A - Surface material of sanitary article - Google Patents

Abstract

PURPOSE:To freely transfer a liquid to an absorbing body, to prevent liquid return and to cover the color of the absorbed liquid, by containing a hydrophobic film provided with openings in at least a part of the surface material covering the surface of the absorbing body and providing membranes protruding toward the absorbing body to the peripheral parts of said openings. CONSTITUTION:A surface material is composed of an opaque hydrophobic film having top parts 1, bottom parts 2 and wall parts 3 connecting both parts or a fiber aggregate having said hydrophobic film laminated thereto. The wall parts 3 have inclined parts and openings 4 are provided to at least a part of the inclined parts and the inclined parts having the openings are not covered with each top part 1 and at least one or more membrane 5 composed of a hydrophobic film protruding toward an absorbing body is present at the peripheral parts of the openings 4. These openings play a role as the passing openings of the liquid discharged from a human body. The total area of the membrane is pref. smaller than the area of the opening parts and pref. present one or more, further pref. two or more per one opening.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention generally relates to a surface material that can be suitably used in sanitary products such as disposable absorbent articles, and more particularly, to a surface material suitable for use in sanitary products such as sanitary napkins and similar products. The present invention relates to a perforated molded film surface material that can be suitably used for sanitary products.

[Conventional technology and its problems]

Absorbent articles used to absorb and retain liquid from the human body have a structure in which an absorbent material that absorbs and retains liquid is interposed between a liquid-permeable surface material and a liquid-impermeable leak-proof film. What is formed is common knowledge. In this absorbent article, the liquid-permeable surface material (sometimes referred to as a topsheet or coverstock) not only allows the liquid to be absorbed to effectively and freely transfer to the absorbent body, but also
There is a need for an absorbent material that does not allow the liquid that has migrated into the absorbent material to flow back, provides a dry touch feeling to the human body, and has a good texture when in contact with the surface of the human body.

To achieve this objective, many proposals have been made and many improvements have been made. For example, by using a nonwoven fabric, which is an aggregate of hydrophobic fine fibers, as the surface material and designing a gap in a hydrophobic atmosphere between the human body surface and the absorbent body, fluid permeability is not impaired, and the flow from the absorbent body is maintained. Technology that reduces liquid return and provides a substantially dry surface (Japanese Patent Application Laid-open No. 18060/1983), and the provision of pores in a hydrophobic liquid-impermeable film,
Technology to further reduce liquid return from the absorber (Special Publication 1987-
17081 and Japanese Patent Application Laid-Open No. 57-1340) are typical examples.

However, in these technologies, in nonwoven fabrics using hydrophobic materials, the liquid that should be transferred to the absorbent body tends to be retained in the microscopic spaces that are inevitably formed as an aggregate of fibers, and when pressure is applied, the liquid is easily retained. The disadvantage is that the fluid migrates to the body surface. Especially in the case of colored fluids such as menstrual blood,
This is a major visual drawback.

On the other hand, it has been proposed that by providing specific pores in a liquid-impermeable film, liquid retention in the surface material can be improved without impairing the original function of the surface material. Therefore, it is necessary to increase the aperture area for free passage of liquid. Due to the loss of hydrophobicity inside the pores, it is not always possible to prevent the liquid from returning in the opposite direction, and in the case of colored liquid absorption, the liquid is observed through the pores, which may not necessarily be the desired surface material. It can not be said.

Therefore, the fluid can be freely transferred to the absorbent body quickly,
Moreover, there is no liquid return, and even when absorbing colored liquid,
It is desired to develop a surface material that can cover the color of the absorbed liquid.

[Means for solving problems]

The present inventors have completed the present invention as a result of intensive studies to overcome the above problems.

That is, the present invention provides a surface material for sanitary products that covers the surface of an absorbent body, which contains a hydrophobic film in which at least a portion of the film is provided with holes, and in which the absorbent body side is provided around the holes. The present invention provides a surface material for sanitary products characterized by being provided with a protruding thin film.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a perspective view showing a typical example of the surface material of the present invention, and FIG. 2 is an enlarged view of the opening.

A preferred surface material of the present invention is composed of an opaque hydrophobic film or a fiber aggregate laminated with a hydrophobic film, which has a top part 1, a bottom part 2, and a wall part 3 connecting these parts, and the wall part 3 has an inclined slope. at least a part of the inclined part is provided with an opening 4, and the inclined part having the opening is not covered by the top part 1 and protrudes toward the absorber side around the opening 4. At least one thin film 5 of hydrophobic film is present. This opening 4 serves as a passage port for liquid discharged from the human body.

The surface material of the present invention has pores in a part of the hydrophobic film, unlike the hydrophobic film having tapered capillary-shaped pores disclosed in Japanese Patent Publication No. 57-17081. By providing a thin film protruding toward the absorbent body around the opening, a large hole can be formed that allows liquid expelled from the human body to quickly transfer to the absorbent body (hereinafter referred to as liquid permeability). Even in the case of open pores, the effect of effectively preventing the liquid from returning to the surface from the absorber after absorbing the liquid (hereinafter referred to as liquid return prevention property) is large. In particular, this effect becomes even greater when the apertures are placed on the slope. The above-mentioned effect can be obtained by simply providing an opening in the inclined part, but by providing a thin film protruding toward the absorber side around the opening in the inclined part, the thin film can move and the effect can be significantly exhibited. The size of the movable thin film varies depending on the material forming the lower layer of the porous hydrophobic film, but at least it does not completely cover the pores, that is, the total area of the thin film is the pores. It is preferably smaller than the area of the part.

It is preferable that there be one or more thin films per opening, and more preferably two or more thin films.

Furthermore, if the sloped section with the apertures is not covered at the top, the apertures will be present in the surface material and the liquid will remain even when the absorbent article is subjected to great pressure by the wearer's body. This is preferable since the permeability does not decrease. On the other hand, if the sloped portion having an opening is covered by the top, the opening may be blocked by the top when pressure is applied, which may significantly reduce liquid permeability.

Another important advantage of providing apertures in the sloped portion of the wall is that liquid is quickly removed from and flows away from the wearer's body surface.

As a result, the user's skin can be kept dry (hereinafter referred to as surface dryness) and the product can be used comfortably.

The apparent thickness of the surface material, that is, the distance between the top and the bottom, can be arbitrarily determined within a range that provides sufficient liquid return prevention properties and surface drying properties, but 0.1 to 5III+ is usually suitable.

The size and density of the apertures can be arbitrarily determined within a range that provides a good balance between liquid permeability, liquid return prevention, and shielding properties, but usually the aperture size is 0.02 to 30 mm. It is preferable that the aperture density is 1 to 100 pores/cIII!.

In addition, the angle between the plane formed by the top connected to the wall having the opening and the slope (α in Figure 5) must be such that the opening is not covered by the top, that is, it is within a range smaller than a right angle. In order to obtain sufficient liquid return prevention and shielding properties, it is usually 2.
More preferably, it is 0" or more.

The hydrophobic film used in the present invention is preferably opaque. When the hydrophobic film itself is opaque, the surface material having apertures of the present invention also becomes opaque, and can be preferably used as a surface material for absorbent articles that absorb colored liquids such as menstrual blood. The opacity of the surface material having the pores is quantified as whiteness (see Examples), and the whiteness is preferably 10% or more.

Note that various methods can be considered as methods for imparting opacity. For example, there are methods of adding white pigments such as titanium oxide and zinc oxide to resin during the film manufacturing process, and methods of coating the film surface by mixing white pigments with a suitable binder such as acrylic, vinyl, or rubber. However, any method other than these methods may be used as long as it can provide a predetermined opacity.

A composite in which a hydrophobic film is further laminated to a fiber aggregate, such as a nonwoven fabric or paper, can also be suitably used in the present invention. Even in the fiber aggregate obtained by laminating this hydrophobic film, the shape of the pores is exactly the same as in the case where the film alone is used. As for the size of the thin film, it is preferable that the size from the fiber aggregate, that is, from the side opposite to the laminated side, is smaller than the aperture area of the fiber aggregate as a total area.

The main components of hydrophobic film are polyolefin,
Copolymers of olefins and other monomers such as acrylic esters and vinyl acetate, polyesters, polyamides, cellulose acetate, and other hydrophobic resins can be used; Copolymers with other monomers are preferred.

As a method for laminating fiber aggregates such as non-woven fabric or paper, known methods can be used, such as lamination using an adhesive such as hot melt, or thermal adhesive lamination from a hot melted thin film. Can be mentioned.

Methods for forming holes in a hydrophobic film include a method of creating irregularities represented by embossing, a suction method using a vacuum, and a pressurizing method using air pressure.
An appropriate method can be selected depending on the constituent resin of the hydrophobic film, the intended shape of the openings, etc.

Furthermore, in order to increase the liquid permeability of these perforated hydrophobic films or hydrophobic laminate films, hydrophilic fibers such as pulp or rayon may be attached to the inside (absorbent side).

Returning to the drawings again, typical examples of the surface material according to the present invention will be explained.

In the surface material shown in FIG. 2, the bottom part 2 is formed adjacent to the opening 4, but the bottom part 2 may be installed apart from the opening 4 as shown in FIG.

However, in the case of the surface material shown in FIG. 2, the liquid discharged onto the bottom quickly transfers to the absorber through the openings 4, but in the case of the surface material shown in FIG. Since liquid may remain in the space formed by 3, it is more preferable to adopt a structure as shown in FIG.

In the surface material shown in FIGS. 2 and 3, the shape of the opening 4 is rectangular, but the shape of the opening 4 is not particularly limited, and can take any shape such as a semicircle as shown in FIG. 4. be able to.

In the above examples, the apertures do not necessarily have to be present on the illustrated wall slopes, but can be present on any wall slope.

As mentioned above, and as can be seen from the examples shown in Figures 1-4, the preferred surfacing material of the present invention is a hydrophobic film or a laminate of hydrophobic films having a top, a bottom and a wall connecting them. It consists of a fiber aggregate,
The wall part has an inclined part, and an opening is provided in at least a part of the inclined part, and the inclined part having the opening is not covered by the top part, and the absorber side is provided in the peripheral part of the opening surface. By adopting a shape with a protruding thin film, fluid can pass through freely even when pressure is applied, there is little liquid return, and even when colored fluid is absorbed, coloring after absorption can be alleviated.
It is a surface material suitable for use in absorbent articles, especially sanitary products such as sanitary napkins that absorb colored liquids such as menstrual blood.

Incidentally, the surface material of the present invention is not limited to the above-mentioned examples, but can be variously modified within the range defined above.

〔Example〕

Hereinafter, how useful the present invention is will be explained with specific examples, but the present invention is not limited to these examples.

Examples 1 to 9 and Comparative Examples 1 to 2 Using the constituent materials shown in Table 1, various surface materials shown in Table 2 were produced by predetermined methods.

The method for measuring the physical properties of each constituent material and surface material will be described below. Note that each physical property value is an average value of 10 measured values.

(1) Method for measuring physical properties of constituent materials ■ Film layer i) Size of aperture: Take an enlarged photograph of the aperture surface viewed from the perpendicular direction using a stereomicroscope, and determine the size of the aperture on the photograph. The diameter A was measured using a branimeter, and the actual aperture size A was calculated using equation (1).

A (mm") -a (mm") / x 2 = (1
) X: magnification of photograph relative to actual object ii) Density of apertures: Measured by counting the number of apertures per 1 cm'' of surface material.

iii) Inclination angle: A cross section of the surface material was photographed as shown in FIG. 5, and the angle indicated by α was measured with a protractor, and this was taken as the inclination angle.

iv) Whiteness: Measurement was carried out using a ND-101DP color difference meter manufactured by Nippon Heavy Industries, Ltd. First, the reflectance of a standard white plate (barium sulfate) for light with a wavelength of 500% m (green) is 100%.
%, the reflectance of each surface material sample to light of the same wavelength was measured, and this was taken as the whiteness. The detailed operating method was based on the "rl0IDP Model Instruction Manual".

■ Fiber layer i) Basis weight: The weight of the fiber layer was measured and the basis weight was calculated.

(2) Surface material: For evaluation, commercially available sanitary napkins “Laurier” (
The surface material (manufactured by Kao ■) was removed and each surface material was constructed instead, and this was evaluated as a hypothetical napkin sample.

■ Absorption time and liquid return amount: Goosebump fiber blood Log 5g/c on napkin sample
The absorption time was defined as the time required for the liquid to be absorbed. Generally, the shorter the absorption time, the better the liquid permeability of the surface material. Afterwards, the pressure was increased to 50 g/cm'', and the amount of test liquid returning from the inside through the surface material was measured, and this was taken as the liquid return amount. The smaller the liquid return amount, the less stickiness on the surface and the better the feeling of use.

■Visual dryness: The state after absorbing 4g of goosebump fiber blood into a hypothetical napkin sample was ranked into the following four categories.

Grade 4: No red color of blood is observed.

Grade 3: Only a slight red color is observed in the blood.

Grade 2: Some red blood is observed.

Grade 1: The red color of the blood is so pronounced that it causes discomfort.

Table 1: Film layer (1) Note) LLDPE: Linear low-density polyethylene (manufactured by Mitsui Petrochemical Corporation) Table 2: Structure and performance of surface material) C-1: Film resin is applied to a thermally bonded nonwoven fabric with the following composition. After laminating, openings in the shape shown in FIG. 2 were formed using an embossing roller.

However, E1: Polyethylene/polypropylene composite fiber with surface hydrophilic treatment (manufactured by Daiwa Boseki ■) SH: Polyethylene/polyester composite fiber with surface hydrophilic treatment (manufactured by Daiwa Boseki ■) PUT: Polyester fiber with surface hydrophilic treatment (manufactured by Daiwa Boseki ■)
As shown in Examples 1 to 9, the surface material of the present invention has a small absorption time and liquid return (2), good visual dryness, and excellent texture. In particular, Examples 1 to 8, which also satisfy claim 2, are at a particularly high level in terms of liquid return prevention properties and visual dryness, and can be said to be truly ideal surface materials. On the other hand, in Example 9, the inclination angle was 6°, that is, the surface material did not substantially have a three-dimensional shape, so it was slightly inferior in liquid return prevention property and visual dryness.

On the other hand, in Comparative Examples 1 and 2, since there is no thin film around the pores, liquid permeability, liquid return prevention property, and visual dryness are poor, and it can be seen that they are insufficient as surface materials. .

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the surface material of the present invention;
The figure is an enlarged view of the opening, FIGS. 3 and 4 are enlarged views of the opening of another embodiment of the surface material of the present invention, and FIG. 5 is a diagram showing a method of measuring the inclination angle. 1: Top 2: Bottom 3: Wall 4: Opening 5: Thin film applicant Kaoru Furuya

Claims (2)

[Claims] 1. A surface material for sanitary products covering the surface of an absorbent body, which contains a hydrophobic film with holes provided in at least a portion thereof, and a thin film protruding toward the absorbent body around the holes. A surface material for sanitary products characterized by: 2. The hydrophobic film has a top part, a bottom part, and a wall part connecting them, the wall part has an inclined part, and a part of the inclined part is provided with an opening, and has an opening. The surface material for sanitary products according to claim 1, wherein the sloped portion is not covered by the top portion.