JP3065756B2 - Surface material of absorbent article and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface material for absorbent articles such as sanitary napkins and disposable diapers, and a method for producing the same.

[0002]

2. Description of the Related Art In general, absorbent articles such as sanitary napkins and diapers include an absorbent for absorbing liquids such as blood and urine, a surface material covering the surface of the absorbent and applied to the skin, and And a back surface material for covering the back surface of the base material to prevent liquid leakage. The surface material of the absorbent article is required to have a liquid permeability for promptly transferring liquids such as blood and urine to the absorber and absorbing the liquid into the absorber. There is a demand for a liquid-return preventing property that does not return the absorbed liquid to the skin side and a light-blocking property that blocks the color of blood or the like diffused in the absorber.

Conventionally, in order to respond to the above demand, a hydrophobic material is used so as not to retain the liquid on the surface material itself, and an opening is provided to impart liquid permeability, or to reduce the liquid passage resistance, Techniques for providing a sparse structure have been proposed. For example, by using a non-woven cloth, which is an aggregate of hydrophobic fine fibers, by forming a space under the hydrophobic atmosphere between the skin and the absorber, the liquid return from the absorber is reduced without impairing the liquid permeability. (See Japanese Unexamined Patent Publication (Kokai) No. 58-18060) or a surface material in which holes are provided in a hydrophobic liquid-impermeable sheet to reduce liquid return from the absorber (Japanese Utility Model Application Laid-Open No. 54-124).
398, JP-B-57-17081, JP-A-57-1340, JP-A-61-45753, etc.).

[0004] Of the above-mentioned surface materials, the latter surface material is further improved, and is provided with a micro embossed surface so that the base surface, which is a non-porous portion, adheres to the skin and does not cause discomfort. Materials have also been proposed.

[0005]

However, since the above-mentioned surface material uses hydrophobic fibers, it is impossible to prevent liquid from accumulating in a minute space in the fiber assembly, and the liquid accumulates when pressure is applied. There is a drawback that the liquid that has been transferred migrates to the surface side (skin side) and gives a sensory discomfort such as stickiness, and also gives a visual discomfort such as staining with blood.

[0006] The latter surface material uses a hydrophobic film and is provided with openings for free passage of liquid. The shape of the opening and the area of the opening are factors that are devised for the free passage of the liquid, and various proposals have been made. Tapered apertures with a capillary force gradient set (JP-A-51-108943), vertical apertures (JP-A-60-259260), and apertures formed on the side wall (JP-A-Hei. 1-334365). These techniques are proposals to design the opening area, which is a measure of liquid permeability, as much as possible and to reduce the contradictory liquid return prevention by creating a three-dimensional aperture. In this case, there is a limit because the liquid permeability is impeded due to hydrophobicity.

Further, since the above-mentioned hydrophobic film is hydrophobic, it folds into close contact with the skin, and easily retains sweat and excreted liquid between the skin and the film, causing discomfort and causing rash. It also causes physical problems such as itching. As an improvement, there has been proposed a method of providing micro unevenness. However, although it has some effect at the initial stage of mounting (at the time of dry), once wet with a liquid, there is a drawback that the effect of providing micro emboss is hardly obtained. Was.

Further, even if any of the above-mentioned conventional surface materials is made of a flexible material, a large shear force acts in the layer direction on the surface of the surface material, and there is a sense of incongruity at the time of mounting.
Therefore, an object of the present invention is to have a liquid permeability that allows a liquid to move freely, and to prevent liquid from returning to the skin side once the liquid has been absorbed, and to have a wearability that does not make the user feel uncomfortable when worn. Another object of the present invention is to provide a surface material of an absorbent article having a shielding property for hiding the color of the absorbed liquid from appearing on the surface.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a surface material of an absorbent article, comprising a liquid-impermeable material and having a myriad of pores, which covers the surface of the absorbent article. In the above, the surface material includes innumerable tops each formed of a convex curved surface, innumerable bottoms, and walls connecting the tops and the bottoms, respectively, and the holes are connected to the tops, Each formed by the wall and the bottom,
And an opening between the tops, a space between the walls, and an opening at the bottom, wherein the openings between the tops, the spaces between the walls, and the openings at the bottom communicate with each other. A communication hole for liquid permeation is formed, and the communication hole has a minimum portion of a cross-sectional opening area between an opening at the top edge on the top side and an opening at the free edge on the bottom side. Has,
An absorbent article characterized in that the opening area increases from the minimum portion toward the top edge on the top side and the opening area is equal or increases toward the free edge on the bottom side. The above object has been attained by providing the surface material of (1).

Further, as a preferable production method of such an absorbent article, a process for the preparation of the surface material of the absorbent article according to claim 1, the spiral braided gold braid because Do that surface material of one of the mold After supplying the surface material forming resin to the surface portion, vacuum suction is performed from the other surface portion of the surface material forming mold, and air is blown from the supply side of the surface material forming resin to form the surface material forming resin. A sheet having a shape along the surface shape of the surface material forming die and having a hole at a position corresponding to the space between the gold braided wires. Is provided.

[0011]

In the case where the surface material of the present invention is used as an absorbent article, the surface material of the present invention can be used in such a manner that once the liquid absorbed by the absorber is pulled in the surface direction (surface direction) of the surface material, The communication hole for liquid permeation is deformed so as to close, and has a liquid return preventing property to prevent the liquid from returning to the skin side, and at the same time, the liquid discharged from the human body through the opening between the top and the bottom side which is the absorber side. The wall portion has a shielding property to shield the liquid absorbed by the absorber, the shearing force is small in any direction along the surface of the surface material, and the top portion is in point contact with the skin And can follow complicated movements, and provides a wearability with a good texture showing a cloth-like feel.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a partially cutaway perspective view of an absorbent article having a surface material according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing one embodiment of the absorbent article of the present invention. FIG. 3 is a cross-sectional view showing a state where the surface material shown in FIG. 2 is cut along the line XX. FIG.
FIG. 5 is a cross-sectional view showing a state cut along the Y line, FIG. 5 is a cross-sectional view showing a state in which body pressure is applied to the surface material of the absorbent article of the present invention, and FIG. FIG. 9 is a cross-sectional view showing a state before forming holes in the surface material manufacturing process, FIG. 9 is a diagram showing a spiral knitted wire mesh used for manufacturing the surface material of the absorbent article of the present invention, A is a plan view, and B is It is a partial expansion perspective view.

The surface material 2 of the absorbent article of the present invention is made of a liquid-impermeable material and has an infinite number of holes 4 covering the surface of the absorbent body 3 of the absorbent article 1 having the absorbent body 3. In the surface material, the surface material 2 includes countless tops 5 each having a convex curved surface, countless bottoms 6, and the tops 5 and 6.
And a wall portion 7 for connecting the holes 4 respectively.
Are connected to the top 5, the wall 7 and the bottom 6
And a hole 5 is formed between the tops 5.
a, a space 7a between the wall portions 7 and an opening 6a in the bottom portion 6
Each having an opening 5 between the tops 5.
a, a space 7a between the wall portions 7 and an opening 6a in the bottom portion 6
Are connected to each other to form a communication hole 8 for liquid permeation. The communication hole 8 has an opening 5 in the upper edge 5e on the top 5 side.
f and the opening 6f at the free edge 6e on the bottom side, and has a minimum portion 5b of the cross-sectional opening area.
b, the opening area increases toward the top edge 5e on the top side and the opening area equals or increases toward the free edge 6e on the bottom side.

The film thickness of the surface material 2 is preferably 15 to 50 μm from the viewpoint of the texture, and is preferably 20 to 40 μm in consideration of strength, cost and the like. Examples of the liquid impermeable material (hydrophobic sheet) constituting the surface material 2 include polyolefins, copolymers of olefins with other vinyl monomers such as acrylates and vinyl acetate,
Examples include hydrophobic thermoplastic resin sheets such as polyesters and polyamides. Among them, from the viewpoint of texture and handling, copolymers of polyolefins or olefins with other monomers, or polymer blend-based hydrophobic thermoplastic resins Sheets are preferred.

Further, the liquid impermeable material is preferably opaque. Even if the liquid-impermeable material is transparent, the color of the liquid such as blood and urine absorbed by the absorber can be blocked by the shape of the top 5, bottom 6, and wall 7 and the like. If the liquid impermeable material itself is opaque, it can be effectively shielded. Various means can be considered as means for making the liquid impermeable material itself opaque. For example, a method is generally used in which a white pigment such as titanium oxide or zinc oxide or a filler such as calcium carbonate, clay or talc is used alone or in combination and added to the surface material during the molding process of the surface material.

The thickness of the surface material 2, that is, the height difference d between the upper edge 5 e of the top 5 and the free edge 6 e of the bottom 6, is 0.2 from the balance between the liquid passage property and the liquid return property. To 3.0 mm, more preferably 0.5 to 2.0 mm
It is. The aperture density of the apertures 5a between the tops 5 is limited by the above-mentioned opening area from the viewpoint of the liquid permeability and the property of preventing the liquid from returning back, but is preferably set to 2 / cm ² to 200 / cm ² . That is, a small opening area, a substantially liquid-permeability is poor when opening density is small, and since the sheet-forming according to the opening area becomes larger inferior, in view of these two / cm ² to 200 DEG Pcs / cm ² .

The circumference of the opening 5a has a minimum length 5b.
Based on the cross-sectional perimeter of the body, at least 5% thereof on the body side 5c and at least 10% on the absorber side 5d, preferably
It must be 8% larger on the body side 5c and 15% larger on the absorber side 5d. By forming the openings 5a between the tops 5 in this way, despite the reduced capillary effect
Good absorption, especially remarkable absorption characteristics for non-fluid, high-viscosity excrement, is observed. Under various stresses), a remarkable improvement in absorption performance was achieved over the surface material having the conventional capillary effect.

The top portion 5 is formed on a convex curved surface having a structure having a void 9. The space 9 allows the top 5 to be in contact with the body, forming a free space between the surface material 2 and the body, and not only preventing sweat and excretion from being present between the body and the film, As shown in the figure, even when pressure (in the direction of the arrow) is applied due to body movement or the like, the surface material 2 can follow the complicated movement of the wearer with the top 5 in point contact with the skin,
Does not give any discomfort.

Further, since the top portion 5 is formed in a convex shape having the void 9, the hole portion 4 fluctuates elastically by the movement of the user, and acts as if by a ciliary movement of a human esophagus. In particular, highly viscous excreted liquid can be effectively transferred to the absorber side. The size of the void 9, i.e. height difference d ₁ between the boundary 2c of the top 5 projecting from the surface member 2 and the surface material 2 is 0.05 to 1.0 mm, considering the elasticity of the film , 0.1 to 0.6 mm.

When the upper edge 5e is used as a surface material of an absorbent article, the top 5 is a portion in contact with the body side at the top 5, and an opening 5f is formed by the opening formed by the upper edge 5e. It is. In addition, as shown in FIG. 4, the top 5 is preferably rounded and has a convex curved surface that gives a soft and dry feeling by point contact with the skin.

The minimum portion 5b of the cross-sectional opening area of the communication hole 8 is formed by the opening 5f of the upper edge 5e and the free edge 6 on the bottom side.
e, between the opening 6f and preferably in the top 5. The cross-sectional area of this minimum part 5b is preferably 0.02 to 9 mm ² , particularly preferably 0.1 to ³ mm ² . If the opening area is smaller than 0.02 mm ² , the liquid permeability is poor, and if it is larger than 9 mm ² , the liquid return property is poor.

The opening area of the opening 5f in the upper edge 5e of the top 5 is preferably 0.04 to 15 mm ² , particularly preferably 0.2 to ⁵ mm ² . The opening area 7b of the space 7a of the wall portion 7 is formed larger than the minimum portion 5b of the opening 5a between the top portions 5, and in this embodiment, the sectional area 7b between the wall portions 7 is It is formed in a so-called divergent shape that expands toward the side. Further, in the present embodiment, the space 7 between the wall portions is formed in a curved shape protruding toward the space 7a.

The sectional area 7b of the space 7a between the wall portions 7 is preferably 0.03 to 10 mm ² , particularly preferably 0.15 to 3.0 mm ² . Above bottom 6
Means that the opening area of the opening 6 a is the space 7 a between the wall portions 7.
Is larger than the cross-sectional area 7b in this embodiment. Opening 6 between the bottoms 6
a is preferably 0.04 to 15
mm ² , particularly preferably 0.2 to ⁵ mm ² .

The free edge 6e of the bottom 6 is a portion that comes into contact with the absorber when placed as a surface material of the absorbent article, and the opening 6f is an opening formed by the free edge. Next, a method for producing the surface material of the absorbent article will be described. Method of manufacturing a surface material of the absorbent articles according to the present invention, after supplying the surface material forming resin on one surface of the gold braid 11 Tona Ru surface member molding die of the spiral braid, the surface member molding die By performing vacuum suction from the other surface of and blowing air from the supply side of the surface material forming resin,
The surface material forming resin is formed on a sheet having a shape along the surface shape of the surface material forming die and having a hole at a position corresponding to a space between the gold braided wires. .

The material of the spiral knitting wire mesh 11 as the surface material forming mold is preferably a metal because it is required to have toughness and cooling properties for solidifying the molten resin. When a metal is used as the material of the spiral knitting wire net 11, it is preferable to coat the spiral knitted wire net 11 with a resin from the viewpoint of anticorrosion properties, releasability and the like. The thermoplastic sheet-like resin on the gold braid 11 is blown with air from the upper part of the spiral braided metal net 11 and pressurized, and at the same time, is vacuum-suctioned from the lower part of the surface material forming die 11. Thereby, the sheet-like molten material is caused to flow along the surface of the wire 11a of the spiral knitted wire mesh, and is cooled and solidified by the wire 11a. On the other hand, air bubbles as shown in FIG. Is ruptured to open the bottom 6.

When the bottom 6 is not opened as shown in FIG. 6, the innumerable tops 5 formed of a convex curved surface have a shape conforming to the surface shape of the wire 11a located at the top of the spiral knitted wire mesh 11. And the innumerable bottoms 4 fall into the space between the wire rods 11a of the spiral knitted wire mesh 11 and are formed as concave curved surfaces that are not opened. According to such a production method of the present invention, by suppressing the pressure applied to the molten resin sheet and the temperature of the resin, the above-described surface material of the absorbent article according to the present invention can be easily and rapidly obtained. .

Next, a specific product according to the present embodiment will be described. As the spiral knitting wire net 11, a 26-mesh wire mesh (SP-26-0.35, manufactured by Kansai Wire Mesh Co., Ltd.) composed of spirals in the same direction with a wire diameter of 0.35 mm.
And TiO ₂ 5% as a sheet-like molten resin
Was used.

The sheet-shaped molten resin is supplied from the T-die onto the spiral knitting wire mesh 9 so as to be 25 g / m ^2, while a vacuum nozzle sucks the lower portion of the spiral knitting wire mesh 11 with a vacuum nozzle, and at the same time, the spiral knitting wire mesh The air heated to 50 ° C from the upper part of 11 was linearly converted to 40 m ³ /
When the amount of min was added, a surface material of a three-dimensionally opened absorbent article having the form of the present invention was obtained. That is, the surface material 2 having the same number of communication holes for liquid permeation as the number of the gold meshes and having three-dimensional openings corresponding to the surface shape of the spiral metal mesh 11 was obtained.

The minimum part 5b in the embodiment is 0.18
mm, the opening area of the opening 5f was 0.7 mm, and the opening area of the opening 6f at the free edge was 0.5 mm.
When the sanitary napkin (absorbent article) 1 as shown in FIG. 1 was manufactured using the surface material 2, the sanitary napkin was excellent in absorbency and dried compared to the sanitary napkin using the conventional surface material. It has a feeling of dryness (there is a feeling of dryness), and despite the low mounting pressure, it has good fit following the movement of the wearer,
It was a pleasant thing that did not give a feeling of strangeness.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, as shown in FIG. 8, the surface material 2 of the absorbent article may be provided with a known micro unevenness 12 on the surface material 2. In this case, the texture of the apertured film can be improved, and the feeling of discomfort when worn can be reduced. The micro unevenness 12 is formed by, for example, mixing a filler or applying pressure to a molded body.

As shown in FIG. 7, the hole 4 has a minimum portion 5b, an opening area 7b of a space 7a between the walls 7, and an opening area 6b of an opening 6a of the bottom 6 are substantially the same. , Wall 7
And the bottom 6 may be formed in a substantially cylindrical shape. Furthermore, spiral knitting wire mesh 1 which is a mold for forming surface material
As 1, a spiral knitting wire mesh using a plurality of stranded wires, a spiral knitting wire mesh having an uneven shape, a spiral knitting wire mesh combining wires having different thicknesses, or the like can be used.

[0032]

According to the surface material of the absorbent article according to the present invention, the surface material of the absorbent article has a liquid permeability that allows the liquid to move freely, and has a liquid return preventing property that does not cause the once absorbed liquid to return to the skin side. In addition, it is possible to satisfy the wearability in which the user does not feel uncomfortable at the time of wearing, and the shielding property of hiding the absorbed liquid so that the color does not appear on the surface.

Further, since the opening area of the free edge on the bottom side is larger or equal to the opening area of the minimum part, the bottom side is formed in a flared shape or a cylindrical shape as a result. , The liquid can be effectively transferred to the absorber, and the highly viscous fluid can also be effectively transferred. Further, a communication hole having a divergent shape or a cylindrical shape is formed from the minimum portion toward the upper edge portion of the top portion which directly contacts the user, and the divergent shape or the cylindrical shape is also formed toward the free edge portion of the bottom portion. Since the communication hole having the shape is formed, when a stress due to the movement of the user is applied, the stress can be relieved and the opening between the top and the bottom can be prevented from being closed.

According to the method for producing an absorbent article according to the present invention, the surface material of the absorbent article can be produced suitably and at a high speed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of an absorbent article provided with a surface material according to an embodiment of the present invention.

FIG. 2 is a sectional view showing one embodiment of a surface material of the absorbent article of the present invention.

FIG. 3 is a cross-sectional view showing a state where the surface material shown in FIG. 2 is cut along the line XX.

4 is a cross-sectional view showing a state where the surface material shown in FIG. 2 is cut along the line YY.

FIG. 5 is a cross-sectional view showing a state in which body pressure is applied to a surface material of the absorbent article of the present invention.

FIG. 6 is a cross-sectional view showing a state before a hole is formed in a manufacturing process of the surface material of the absorbent article of the present invention.

FIG. 7 is a sectional view showing another embodiment of the surface material of the absorbent article of the present invention.

FIG. 8 is a sectional view showing still another embodiment of the surface material of the absorbent article according to the present invention.

FIG. 9 is a diagram showing a spiral knitted wire mesh used for manufacturing a surface material of the absorbent article of the present invention, where A is a plan view,
B is a partially enlarged perspective view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorbent article 2 Surface material 4 Hole 5 Top 5a Opening between tops 5b Minimum part 6 Bottom 6a Opening at bottom 6b Opening area of opening at bottom 7 Wall 7a Space between walls 7b Between walls Open area of space

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI A61F 13/54 (56) References JP-A-4-364843 (JP, A) JP-A-2-107251 (JP, A) Kaihei Hei 1-249052 (JP, A) Real Kaihei Hei 2-17126 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61F 13/15-16/84

Claims (5)

(57) [Claims] 1. A surface material of an absorbent article having an infinite number of holes, which is made of a liquid-impermeable material and has an infinite number of pores, which covers the surface of the absorbent article. An innumerable top portion having a convex curved surface, an innumerable bottom portion, and a wall portion connecting each of the top portion and the bottom portion, wherein each of the holes is connected to the connected top portion,
A structure formed by the wall portion and the bottom portion, and having an opening between the top portions, a space between the wall portions and an opening portion on the bottom portion, wherein the opening between the top portions and the between the wall portions are provided. The space and the opening at the bottom communicate with each other to form a communication hole for liquid permeation. The communication hole has an opening at the upper edge at the top and an opening at the free edge at the bottom. A minimum portion of the cross-sectional opening area between the first and second portions, the opening area increases from the minimum portion toward the top edge on the top side, and the opening area increases toward the free edge on the bottom side. A surface material for an absorbent article characterized by being equal or increasing. 2. The surface material of an absorbent article according to claim 1, wherein the minimum portion exists in an opening between the tops. 3. The surface material for an absorbent article according to claim 1, wherein an opening area of the opening at the bottom is larger than a cross-sectional area of a space between the walls. 4. The surface material for an absorbent article according to claim 1, wherein an opening area of the bottom opening is equal to a cross-sectional area of a space between the wall portions. 5. A method for producing a surface member of an absorbent article according to claim 1, wherein, after supplying the surface material forming resin on one surface of the surface member mold that Do from knitting gold spiral knitting By performing vacuum suction from the other surface of the surface material forming die and blowing air from the supply side of the surface material forming resin, the surface material forming resin is shaped into the surface shape of the surface material forming die. A method of manufacturing a surface material of an absorbent article, comprising forming a sheet having a shape along the sheet and having a hole at a position corresponding to a space between the gold-knitted wires.