JPH0653128B2 - Absorbent article - Google Patents

Description

TECHNICAL FIELD The present invention relates to absorbent articles such as sanitary napkins and diapers, and particularly to absorbent articles provided with a surface material excellent in liquid passage property and liquid return prevention property. It is a thing.

(Prior Art) As is well known, absorbent articles such as sanitary napkins and diapers,
A water absorbent core material such as wood pulp, rayon, and cotton is provided, a waterproof material is provided on the back side thereof, and a surface material called a top sheet is provided on the surface side in contact with the skin.

As a surface material for recent absorbent articles, a non-woven sheet or a plastic film provided with a large number of pores is applied to eliminate the liquid remaining on the surface material when worn and the liquid return from the absorbent core material. Alternatively, various ideas have been made for various aspects such as cleanliness of appearance after use. For example, JP-A-63-2
The surface material described in Japanese Patent No. 9640 is formed of an opaque plastic film sheet having holes formed by a large number of pins. When the surface material made of this plastic film is used for an absorbent article, the surface of the absorbent article can be covered opaquely, and since flaps or burrs remain around the holes when the pins are drilled, the absorbent core material can be used. There is an advantage that the absorbed liquid is prevented from reversing and the liquid in the absorbent core is difficult to see after use, and this kind of surface material has been widely used especially for sanitary napkins.

(Problems to be solved by the invention) However, when the absorbent core material is covered with the surface material of the conventional perforated film described above, it is difficult to adhere the surface material and the absorbent core material over the entire surface, and the film A gap is partially formed between the absorbent core material and the absorbent core material, and the ability of the liquid to permeate the absorbent core material is reduced in this clearance portion. This inconvenience can be improved to some extent by applying a hydrophilic substance to the surface material,
When a hydrophilic substance is applied, the dry feeling during use will be impaired. Further, the flaps or burrs generated at the time of perforation also have an effect of making dirt of the absorbent core material less visible after use, but since each hole of the surface material is a through hole having no bottom portion, the surface material becomes opaque. Even if it is done, the stains will look like spots.

The object of the present invention is to provide a surface material which has a small amount of liquid returning and is excellent in the liquid introduction property to the absorbent core material side and the dryness of the surface, and further, the dirt of the absorbent core material after use is less visible. To provide an absorbent article.

(Means for Solving the Problems) In order to achieve the above object, a body fluid permeable surface material is arranged on the surface side of the absorbent core material, and a body fluid impermeable leak preventer is arranged on the back surface side. In the absorbent article, the surface material is composed of a composite sheet in which a heat-adhesive film having an opaque surface and a thin non-woven fabric of thermoplastic fibers are heat-bonded, and a large number of pores are formed on the film surface of the composite sheet. Each of the strips extruded from the fine pores when the fine pores are formed is depressed from the film surface and crimped to the nonwoven fabric, and the strips are depressed to the inner peripheral edge of each pore and crimped to the nonwoven fabric. The outer edge of the strip is separated,
An annular gap is formed between the inner peripheral edge of the pores and the outer peripheral edge of the strip so that body fluid permeates the nonwoven fabric through the annular gap and is absorbed by the absorbent core material. Is.

As the opaque heat-adhesive film for the surface material, various synthetic resin films containing calcium carbonate or titanium oxide can be applied, but from the viewpoint of texture, relatively low melting point polyethylene containing calcium carbonate is preferable. . And the thickness is 3 to 50 μm, preferably 20 to 40 μm.
m is suitable, and the aperture ratio due to the pores is 20% or more. When the thickness of the film is less than 3 μm, the heat shrinkage becomes large, and when it exceeds 50 μm, it becomes difficult to obtain desired pores and the texture becomes hard.

The thermoplastic fibrous nonwoven fabric backed by the film is preferably one in which at least a part of the surface is made of synthetic fiber of the same quality as the film, and when the film is polyethylene, the sheath component is polyethylene and the core component is A basis weight obtained by heat-processing a composite fiber web of polypropylene or polyester 8 to 50 g / m ² , with a specific volume of 20 to 60 cm
A thin non-woven fabric of ³ / g, especially a non-woven fabric having a basis weight of 16 to ³⁰ g / m ² is suitable. If the basis weight of the nonwoven fabric is less than 8 g / m ² , a desired annular gap cannot be obtained between the inner peripheral edge of the pores and the outer peripheral edge of the strip,
If it is more than 50 g / m ^2, it becomes a noble material as a surface material. Further, when the specific volume is less than 20 cm ³ , the body fluid permeation rate becomes slower, and when it exceeds 60 cm ³ , the surface material becomes sublime. As a method of forming a large number of pores in the composite sheet made of the above-mentioned film and nonwoven fabric, a large number of small projections having a top surface of a truncated cone shape, a truncated pyramid shape, or a cylindrical shape, a prismatic shape, etc. It is desirable to pass the composite sheet between a pair of rollers consisting of a perforating roller and a smoothing roller, and to allow small projections of the perforating roller to penetrate the film by embossing from the film surface side. If heated to a temperature around the melting point of the film, the fine particles extruded on the top surface of the small protrusions at the time of perforation are bonded to the nonwoven fabric in a state of being depressed from the film surface, and each of the pores opened in the film surface A hole structure in which an inner peripheral edge is separated from an outer peripheral edge of each strip that is depressed and pressure-bonded to a nonwoven fabric, and an annular gap is formed between the inner peripheral edge of the pore and the outer peripheral edge of the strip. You can do it. The distribution density (number), diameter, and gap area of the pores are selected depending on the use of the absorbent article, but in the case of sanitary napkins and sanitary materials such as diapers, the film surface is not perforated. The opening size of one of the provided pores is 0.5 to 3 mm ² , the opening ratio is 20 to 60%,
The depth of depression of the strip is 0.6 to 1.2 mm, and the ratio of the opening size of the pores to the size of the strip is preferably 1: 0.4 to 1: 1. When the diameter is about 1 mm and the depression depth is about 1 mm, the area of the gap between the inner peripheral edge of the pore and the outer peripheral edge of the strip is calculated to be about 4.1 mm ² , but actually it is smaller than this. Slightly smaller When the total clearance area is small such that the opening ratio is 20% or less and the depression depth is less than 0.6 mm, the passage of body fluid to the absorbent core is not smooth, and the opening ratio is 60% or more and the depression depth is If is larger than 1.2 mm, the total clearance area will be too large, and the amount of liquid returned after use will increase.

(Function) The porous film as the surface layer of the composite sheet allows the liquid to flow through the pores to the absorbent core material, and the nonwoven fabric bonded to the film promotes the movement of the liquid to the absorbent core material. Eliminates liquid residue on the film surface, and eliminates the feeling of dampness on the film surface, which touches the skin during use. Then, the recessed strips suppress the dirt of the absorbent core material from being directly visible through the pores to eliminate the feeling of filth after use and prevent the backflow of the liquid.

(Example) An example of the present invention will be described below with reference to the drawings.
FIG. 1 is a front perspective view of a sanitary napkin, and FIG. 2 is a cross-sectional view. (1) shows a surface material, (2) shows an absorbent core material, and (3) shows a leak preventer.

The surface material (1) is composed of a composite soot (6) in which an opaque thermo-adhesive film (4) and a thermoplastic fiber thin non-woven fabric (5) are adhered as shown in FIGS. 3 and 4. Become. A medium-density polyethylene film having a thickness of 20 μm in which calcium carbonate was mixed in the heat-adhesive film (4) in the present Example [Poulum 20 (density 0.9 g / cm ³ ) manufactured by Tokuyama Soda Co., Ltd.]
(Mp 125 ° C.)] is used also thermoplastic fibers of the nonwoven fabric (5) sheath component is high density as polyethylene, the core component is a polyester conjugate fiber [Daiwa Spinning Co., NBFSH3 ^D
A thin non-woven fabric (apparent thickness of about 0.8 mm) with a basis weight of about 30 g / m ^{2 which} is made by joining the fibers by melting the sheath component is used. ing. Then, the opacified heat-adhesive film (4) and the fibrous nonwoven fabric (5) are heat-bonded to each other to form a film.
A large number of pores (7) with a diameter of 1.8 mm are regularly distributed on the surface of (4), and the aperture ratio occupied by these many pores (7) is about 40% (pore density: 20). / Cm ² ). In addition, the fiber non-woven fabric (5) in each of the pores (7) has a recess (8) that is recessed by about 0.7 mm from the surface of the film (4).
On the bottom surface of (8), there is a strip extruded from the pores when punching.
(9) are adhered, and the inner peripheral edge of the pores (7) and the strip
The outer peripheral edge of (9) is separated, and the film (4) is ruptured between the outer peripheral edge of the strip (9) and the inner peripheral edge of the pores (7). It has a structure in which an annular gap (10) that allows liquid to enter from the surface is formed in the nonwoven fabric (5).

The surface-perforated composite sheet (6) having the above-described structure is a perforated sheet having a large number of truncated cone-shaped small projections (11) (11) on the outer peripheral surface, as schematically shown in FIGS. 5 and 6, for example. A slight gap between the roller (12) and the roller with smooth surface (13) (to the extent that they do not contact)
The perforating roller using a device that holds the
(12) is heated to 130 to 135 ° C. and the smooth roller (13) is heated to 90 to 95 ° C., and the heat adhesive film (4) is fed from one side of the apparatus.
It can be obtained by passing between the rollers (12) and (13) rotating in the direction of the arrow while superimposing the above and the above-mentioned heat-adhesive non-woven fabric (5) on top of each other. That is, when the heat-adhesive film (4) and the heat-adhesive non-woven fabric (5) are supplied while being superposed between the heated rollers (12) and (13), the film is formed.
(4) is softened by the effect of heat of the perforation roller (12), the projections (11) of the perforation roller (12) are softened or the film (4) is melted and cut, and the small projections are formed. A circular strip (9) whose top surface (11A) of (11) is separated from the perforated part is a non-woven fabric.
It can be manufactured by pushing it into the inside of (5), pressing it toward the lower surface side of the nonwoven fabric (5), and thermally adhering the strip (9) to the nonwoven fabric (5). Of course, the above-mentioned punching roller
Instead of the (12) and the smoothing roller (13), the heating punched plate having a large number of small projections can also be manufactured by a punching method of moving up and down toward the table.

When the thermoplastic heat-adhesive film (4) is perforated using the perforated roller (12) or perforated plate heated as described above, when the strip (9) is extruded during perforation, the inner circumference of the perforated part is One part of the film (4) is softened or melted in contact with the side surface of the small protrusion (11), and as shown in FIG. 7, the one part of the film is stretched to become a filament (14) by the softening or melting. In some cases, they may remain in a row between the inner peripheral edge of the fine hole (7) and the outer peripheral edge of the strip (9). However, this filament (14)
Is small and does not significantly affect the above-mentioned annular gap, and the inner peripheral edge of the pore (7) and the outer peripheral edge of the strip (9) are substantially separated.

When the composite sheet of the present invention is used as a surface material of a sanitary napkin, the shape of the above-mentioned strip (9) is a shape which is swollen toward the pores (7) as shown in FIG. Is preferable, and it is possible to prevent the liquid from staying on the strip (9) and further improve the cleanliness after use. Such a bulged strip (9) can be obtained by using a small projection for perforation whose top surface is hollow.

In addition, when cylindrical small projections for perforation having almost the same diameter in the height direction are used, as shown in FIG. 9, a strip (9) of approximately the same size as the openings of the pores (7) is made of non-woven fabric ( 5) glued to
The color of the liquid absorbed by the absorbent core becomes more difficult to see from the side of the film (4), and the sanitary napkin equipped with such a surface material has excellent liquid absorption and prevention of return of absorbed liquid. Will be things.

In order to confirm the performance of the absorbent article of the present invention described above, as shown in Table 1, five types of sanitary napkins belonging to the present invention and four types of comparative products were prepared. The results are shown in Table 2.

Further, the absorbent core material is the same as in Example. In both comparative examples, the density is 0.8 g / cm ³
-Pulverized wood pulp having an apparent thickness of about 8 mm was used, and a polyethylene film having a thickness of 35 μm was used as a leak preventer.

The opening ratio in the examples (Table 1) indicates the ratio of the annular gap area (gap area × pore density) per cm ² of the surface material, and the gap area of the comparative example is the opening area of the bored holes. Shows.

Test method 1) Liquid absorption time: Spread the above leak preventive material under the above absorbent core material, put each surface material of Table 1 on the absorbent core material, and set 6.8g.
The time for which 10 ml of artificial menstrual blood is dropped from the surface material under a load of / cm ^{2 and} the artificial menstrual blood is absorbed in the absorbent core material.

2) Liquid return amount: After absorbing artificial menstrual blood, leave it for 1 minute, stack 3 pieces of weight-measured paper (7cm * 12cm) on top of the surface material, and apply a load of 28g / cm ^{2 to} the entire surface. After leaving it to stand for 1 minute, the weight of the paper was measured and the amount of returned liquid was calculated.

3) Shielding property: The state after the artificial menstrual blood was absorbed by the absorbent core material was visually observed from the surface material side and classified into the following grades.

Grade 4 ... The color of artificial menstrual blood is barely noticeable.

Grade 3 ... The color of artificial menstrual blood is slightly visible.

Grade 2 ... The color of artificial menstrual blood looks pretty.

1st grade: The color of artificial menstrual blood looks discomforting.

The artificial menstrual blood used was a mixture of 20% glycerin, 79.8% distilled water, and 0.2% Congo Red.

(Effects of the invention) As described above, the absorbent article according to the present invention has the water-absorbent core material (2).
In an absorbent article that has a body fluid impermeable leak preventer (3) on the back side and a body fluid permeable surface material (1) on the front side, the surface material (1) becomes opaque. The heat-adhesive film (4) and the thin non-woven fabric (5) of thermoplastic fibers are heat-bonded to form a composite sheet (6), and the composite sheet (6) has a large number of films (4) on its surface. The pores (7) of the
The strips (9) extruded from the pores at the time of perforating (7) are depressed from the film surface and pressed onto the non-woven fabric (5), and the inner peripheral edge of the pores (7) and the strips ( 9) The outer peripheral edge of the
An annular gap between the inner peripheral edge of (7) and the outer peripheral edge of the strip (9)
Since (10) is formed, when used as an absorbent article, for example, as a sanitary napkin, the body fluid discharged to the surface side of the film (4) has an annular gap (10) from a large number of pores (7). Smoothly flows into the absorbent core through the non-woven fabric (5) and is absorbed, and almost no liquid remains on the film surface, and liquid does not return to the film side, and there is no uncomfortable feeling of wetness during wearing. can do. In addition, since there is a strip (9) on the bottom of the depression (8) of each pore (7), which is separated from the film, dirt on the absorbent core is hard to see from the film surface side after use, and it feels unclean. Can be resolved.

[Brief description of drawings]

The drawings show an embodiment of the present invention.
FIG. 2 and FIG. 2 are a perspective view and a sectional view of an absorbent article, FIGS. 3 and 4 are a sectional enlarged view and a partial plan view of a composite sheet, and FIG.
The figure is an enlarged view of the main part of FIG. 5, FIG. 7, FIG. 8 and FIG.
The drawings are cross-sectional enlarged views showing other aspects of the perforated portion. 1: Surface material, 2: Absorbent core material, 3: Leak preventive material, 4: Thermal adhesive film, 5: Thermal adhesive non-woven fabric, 6: Composite sheet, 7: Pore, 8: Dimple, 9: Strip, 10: Ring Gap

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location 2119-3B A41B 13/02 B

Claims (3)

[Claims] 1. An absorbent article in which a body fluid impermeable leak preventer is disposed on the back surface side of a water absorbent core material, and a body fluid permeable surface material is disposed on the front surface side, wherein the surface material is opaque. The heat-adhesive film and the thin non-woven fabric of thermoplastic fibers are heat-bonded to form a composite sheet, and a large number of pores are formed in the film surface of the composite sheet. The strips extruded from the pores are depressed from the film surface and crimped onto the nonwoven fabric, and the inner peripheral edge of each pore is separated from the outer edge of each strip depressed and crimped onto the nonwoven fabric to separate the pores. An absorbent article, characterized in that an annular gap is formed between the inner peripheral edge and the outer peripheral edge of the strip. 2. The thickness of the heat-adhesive film as the surface material is 3 to 5
The absorbent article according to claim 1, which has a thickness of 0 μm. 3. A thermoplastic fiber non-woven fabric as a surface material having a basis weight of 8 to 5
The absorbent article according to claim 1, which has a specific volume of 0 g / m ² and a specific volume of 20 to 60 cm ³ / g.