JPH0775616B2 - Surface material for sanitary goods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention generally relates to a surface material that can be suitably used for sanitary articles such as disposable absorbent articles, and more specifically, sanitary napkins and similar articles. The present invention relates to a surface material for a perforated molded film which can be suitably used for the sanitary ware.

[Conventional technology and its problems]

The absorbent article used for absorbing and retaining liquid from the human body has a structure in which an absorbent body for absorbing and retaining liquid is interposed between a liquid-permeable surface material and a liquid-impermeable leak-proof film. What is formed is public knowledge. In this absorbent article, it goes without saying that the liquid-permeable surface material (sometimes referred to as the topsheet or coverstock) effectively and freely transfers the liquid to be absorbed into the absorber.
It is desired that the liquid transferred to the absorbent body does not return to give a dry touch feeling to the human body and that the skin feels good when it comes into contact with the human body surface.

To achieve this purpose, many proposals have been made and many improvements have been made. For example, using a non-woven fabric, which is a hydrophobic fine fiber aggregate, as the surface material and designing a gap between the human body surface and the absorbent body in a hydrophobic atmosphere, the fluid permeability is not impaired, and A technique for reducing liquid return and providing a substantially dry surface (Japanese Patent Laid-Open No. 58-18060)
Alternatively, a technology to further reduce the liquid return from the absorber by providing holes in the hydrophobic liquid impermeable film (Japanese Patent Publication No. 57-17081,
Typical examples are JP-A-57-1340).

However, in these techniques, in a non-woven fabric using a hydrophobic material, the liquid to be transferred to the absorber is easily retained in the minute space inevitably formed as an aggregate of fibers, and easily retained when pressure is applied. There is a drawback that the liquid migrates to the body surface. Especially, in the case of menstrual blood-colored liquid, it is a major visual defect.

On the other hand, it has been proposed that a liquid-impermeable film is provided with specific openings to improve the retention of the liquid of the surface material and not to impair the original function of the surface material. Therefore, it is necessary to increase the aperture area for the free passage of liquid. Due to the loss of hydrophobicity inside the opening, it is not always possible to prevent the liquid from returning in the opposite direction, and in the case of absorbing colored liquid, the liquid is observed from the opening and it is not always the desired surface material. It can not be said.

Therefore, as soon as possible, the fluid can be freely transferred to the absorber,
Moreover, there is no liquid return and even when absorbing colored liquids,
The appearance of a surface material that can cover the color of the absorbed liquid is desired.

[Means for solving problems]

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

That is, the present invention comprises an opaque hydrophobic film having a concave portion composed of a top portion, a bottom portion and a wall portion connecting them, and the wall portion has an inclined inclined portion, and at least a part of the inclined portion. The present invention provides a surface material for a sanitary article, which is characterized in that an opening is provided in the opening, and the inclined portion having the opening is not covered by the top.

Hereinafter, the present invention will be further described 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 portion thereof. The surface material of the present invention comprises a top portion 1, a bottom portion 2 and a wall portion 3 connecting them.
Is formed of an opaque hydrophobic film having a recessed portion, the wall portion 3 of which has an inclined portion, and an opening 4 is provided in at least a part of the inclined portion. The slopes that it has are not covered by the top. The opening 4 serves as a passage port for the liquid discharged from the human body.

The surface material of the present invention is different from the hydrophobic film having tapered capillary-shaped openings disclosed in Japanese Patent Publication No. 57-17081 in that it absorbs a recolored liquid. Even in the case of a large opening that can quickly transfer the liquid discharged from the human body (hereinafter referred to as liquid permeability) by providing the The effect of preventing the liquid from returning (hereinafter referred to as the liquid returning prevention property) and the effect of shielding the colored portion absorbed in the absorber (hereinafter referred to as the shielding property) are both large. Furthermore, because the sloped part with the apertures is not covered by the top, the apertures are present in the surface material and the liquid permeation even when the absorbent article is under significant pressure by the wearer's body. There is no decrease in sex. On the other hand, if the sloped part with the opening is covered by the top,
When pressure is applied, the pores are blocked by the tops, so that the liquid permeability is significantly reduced, and this is not the intention of the present invention.

Another important advantage of providing an aperture in the ramp of the wall is that the liquid quickly separates from the wearer's body surface and that the liquid flows away from the body surface. As a result, the user's skin can be kept dry (hereinafter referred to as surface dryness) and can be used comfortably.

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

The size of the openings and the density of the openings can be arbitrarily determined within a well-balanced range of the liquid permeability, the liquid return prevention property, and the shielding property, but usually the size of the holes is 0.02 to 30 mm ² . In addition, the open pore density is preferably 1 to 100 holes / cm ² .

Further, the angle (α in FIG. 2) between the plane formed by the apex connected to the wall having the opening and the inclined portion is arbitrarily determined within a range in which the opening is not covered by the apex, that is, smaller than a right angle. I can, but
Generally, it is preferably 20 ° or more in order to obtain sufficient liquid return prevention property and shielding property.

The hydrophobic film used in the present invention is required to be opaque. Since the hydrophobic film itself is opaque, the surface material having pores of the present invention is also opaque and can be preferably used as a surface material for absorbent articles that absorb colored liquid such as menstrual blood. The opacity of the surface material having the openings is quantified as whiteness (see Examples), and the whiteness is preferably 20% or more.

Various methods are conceivable as a method for imparting opacity. For example, a method of adding a white pigment such as titanium oxide or zinc oxide to the resin in the film manufacturing process, a method of coating the surface of the film with a white pigment mixed with a suitable binder such as acrylic, vinyl or rubber can be used. However, as long as a predetermined opacity can be given, any method other than these methods may be used.

The main components of the hydrophobic film are polyolefin,
Although any hydrophobic resin such as a copolymer of an olefin and an acrylic ester, another monomer such as vinyl acetate, polyester, polyamide, cellulose acetate or the like can be used, generally from the viewpoint of texture, polyolefin or olefin and another monomer Is preferable.

As a method of forming a hole in a hydrophobic film, there are engraving method of unevenness typified by embossing, suction method by vacuum, pressure method by air pressure, etc.
An appropriate method can be selected depending on the constituent resin of the hydrophobic film, the desired shape of the opening, and the like.

Referring back to the drawings again, a typical example of the surface material according to the present invention will be described.

In the surface material shown in FIG. 2, the bottom portion 2 is formed adjacent to the opening 4, but the bottom portion 2 may be installed separately 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 is rapidly transferred from the opening 4 to the absorber, but in the case of the surface material shown in FIG. Since the liquid may be retained in the space formed by 3, it is more preferable to adopt the 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 as shown in FIG. 4 or 5, a trapezoid, a semicircle, etc. Can take any form of. Further, as shown in FIG. 6, a plurality of openings 4 may be provided in the inclined portion of one wall portion, or as shown in FIG. The holes 4 may be formed.

In the example shown in FIG. 8, the wall portion 3 having no aperture forms the shape of a circular segment, and the aperture 4 is provided over the entire inclined portion of the adjacent semicircular wall portions. FIG. 9 is a plan view of this as viewed from above. in this case,
The bottom exists as a point or line in the wall that maximizes the distance to the top plane.

In the example shown in FIG. 10, an opening 4 is provided in an inclined portion of a wall which is surrounded by a wall having no opening and a top, and the bottom 2 defines a boundary between one wall and the opening. It exists as an eggplant line.

FIG. 11 shows an example in which the wall portion 3 having the opening 4 forms a conical shape. Also in this case, the number and shape of the openings 4 and whether or not the bottom portion 2 is adjacent to the openings 4 can be freely selected.

In the above examples, the apertures do not necessarily have to be present in the illustrated wall ramps, but can be in any wall ramp as long as the apertures are not covered by the top.

As described above, as can be understood from the examples shown in FIGS. 1 to 11, the surface material of the present invention comprises a hydrophobic opaque film having a top portion, a bottom portion, and a recessed portion constituted by a wall portion connecting them. , The wall has an inclined slope, at least a part of the slope has an opening, and the slope having the opening has a shape not covered by the top, so that the pressure is Even if added, the fluid can pass freely, there is little liquid return, and even when absorbing colored fluid,
It is a surface material that is suitable for use in hygiene articles such as sanitary napkins that absorb colored liquids such as menstrual blood and that can alleviate coloring after absorption.

The surface material of the present invention is not limited to the above-mentioned examples, and various modifications can be made within the range defined above.

〔Example〕

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

Examples 1 to 23 and Comparative Examples 1 to 3 Surface materials according to the present invention or comparative surface materials of various shapes made of the constituent resins shown in Table 1 were produced, and their performances were evaluated by the methods described below.

The results are shown in Table 1.

All the surface materials were manufactured by embossing a film made of a predetermined resin. In addition, in the surface materials except Comparative Example 1, about 10% of titanium oxide was used as a white pigment.
It is included by weight percent.

In the evaluation of the absorption time, the liquid return and the visual dryness, the surface material of commercially available Laurier (manufactured by Kao Co., Ltd.) was removed, and instead each surface material was constituted and evaluated as a napkin supposed sample.

<Measurement method> (1) Size of the opening: An enlarged photograph of the opening surface viewed from the right direction is taken using a stereomicroscope, and the size a of the opening on the photograph is measured using a planimeter. The measurement was performed, and the size A of the full-scale aperture was calculated by the formula (1).

x: Magnification of photograph with respect to the actual product (2) Open hole density: Measured by counting the number of open holes per cm ^{2 of the} surface material.

(3) Opening angle: A cross-section of the surface material was photographed using a stereoscopic microscope as shown in Fig. 14, and the angle indicated by α in Fig. 14 was measured with a protractor. did.

(4) Whiteness: Using the ND-101DP type colorimetric color difference meter manufactured by Nippon Denshoku Industries Co., Ltd., 500 mn on a standard red mount under illumination under the same conditions.
Absolute reflectance R ₀ for light of wavelength (green) and absolute reflectance R for light of the same wavelength in each surface material sample were measured,
The whiteness R _r of each surface material sample was calculated by the equation (2). The specific operation method was based on the “ND-101DP type instruction manual”.

(5) Absorption time, amount of liquid returned: 10 ml of the test liquid was injected under a pressure of 5 g / cm ² , and the time required for absorption by the assumed napkin sample was defined as the absorption time. The smaller the absorption time, the better the liquid permeability. Then, after a certain period of time, the pressure was increased to 50 g / cm ² , and the amount of the test liquid returning from the inside through the surface material was measured and defined as the liquid return amount. The smaller the amount of liquid returned, the less sticky the surface and the better the feeling of use.

(6) Visual dryness: The state after absorbing 4 g of horse defibrinated blood in the assumed napkin sample was classified as follows by sensory evaluation.

⊚: Red blood is not observed at all.

○: Only a slight red color of blood is observed.

Δ: Red color of blood is considerably recognized.

X: The red color of blood is very noticeable.

[Effects of the Invention] As shown in Examples 1 to 23, the surface material according to the present invention has a small absorption time and return amount, and has good visual dryness, and is an absorbent article, especially coloring of menstrual blood and the like. It can be seen that it is suitable for use as a sanitary napkin that absorbs the liquid.

In Comparative Example 1, since the whiteness of the film itself is low, the color of the test liquid diffused in the absorber can be seen through, and thus the visual dryness is poor.

In Comparative Example 2, since the surface material is provided with an opening at the bottom, the surface material has low whiteness and poor visual dryness, and the liquid return amount is large, resulting in a surface material for absorbent articles. It cannot be said to have sufficient performance.

In Comparative Example 3, since the opening angle is 90 ° or more, the holes are closed at the time of pressurization, the absorption time becomes extremely long, and it is extremely unsuitable for use as the surface material of the absorbent article. .

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the surface material of the present invention, and FIG.
8 to 10, FIG. 10 and FIG. 11 are enlarged views of the open hole portion showing the embodiment of the surface material of the present invention, and FIG. 9 is a plan view of the surface material having the holes shown in FIG. 12 and 13 are enlarged views of the hole portion of the comparative surface material, and FIG. 14 is a diagram showing the method for measuring the hole angle. 1: Top, 2: Bottom 3: Wall, 4: Opening

Continuation of front page (56) References JP-A-60-259260 (JP, A) JP-B 57-17081 (JP, B2)

Claims (3)

[Claims] 1. An opaque hydrophobic film having a concave portion composed of a top portion, a bottom portion and a wall portion connecting them, the wall portion having an inclined slant portion, and at least a part of the slant portion. Is a surface material for a sanitary article, which is provided with an opening, and the inclined portion having the opening is not covered by the top. 2. The surface material according to claim 1, wherein the size of the openings is 0.02 to 30 mm ² and the density of the openings is 1 to 100 holes / cm ² . 3. The surface material according to claim 1, wherein the angle between the plane formed by the apex connected to the wall having an opening and the inclined portion is smaller than a right angle and is 20 ° or more.