JP2942069B2 - Method for producing surface material of absorbent article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface material for absorbent articles such as sanitary napkins and 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 body fluids such as blood and urine, a surface material covering the absorbent and in contact with the skin, and a back surface of the absorbent. And a backing material to prevent liquid leakage. The surface material of the absorbent article is required to have liquid permeability in order to promptly transfer bodily fluids such as blood and urine to the absorbent body, and to be in close contact with the skin and not to cause discomfort, and to have the bodily fluids on the skin side. There is a demand for a liquid return preventing property that does not return to the surface.

Conventionally, there has been proposed a surface material or the like in which holes are provided in a hydrophobic liquid-impermeable sheet to reduce liquid return from the absorber. For example, as shown in FIG. Hole 3
1 is formed by a punching plate mold 32 having a flat surface. Such a surface material 30 prevents liquid return or the like, but gives a feeling of discomfort because the base surface, which is the non-opening portion 33, adheres to the skin. For this reason, a surface material treated by micro embossing or the like has been proposed. In addition, as a surface material, a thermoplastic resin is melted from the upper surface of a surface material forming die formed of a wire mesh to form a vertically-stretched film, and the lower surface of the surface material forming mold is suctioned under reduced pressure to form a space between wire wires of the wire mesh. There has been proposed a perforated sheet formed by a T-die melt forming method or the like in which holes are formed at corresponding positions. This sheet has an uneven surface, and an opening for liquid permeation is formed in the bottom of the concave portion, and is excellent in liquid return prevention and skin contact feeling.

[0004]

However, although the embossed surface material can easily form a hole from a hydrophobic film substrate, the embossed surface material has an embossing effect once wetted with a liquid. You may not be able to see it. In addition, although a sufficient opening is formed in the surface material by the T-die melt molding method, a concave wall corresponding to the opening diameter,
In other words, the length of the three-dimensional hole becomes long, and the opening is often closed during winding or actual use during manufacturing, and thus may not be practically usable. Accordingly, an object of the present invention is to provide a surface material of an absorbent article which does not substantially reduce the permeability of body fluid and has an excellent skin contact feeling, and a method for producing the same.

[0005]

SUMMARY OF THE INVENTION The present invention provides a molten resin filter.
And the molten resin.
The film is sucked from below the surface material forming mold and
Once a large number of recesses are formed in the oil film,
Heat shrink to form an easy-opening portion in the recess,
On the surface material forming die, hot air and suction treatment are applied
To open or expand the easy-to-open part and project it out for liquid permeation.
Surface material for absorbent articles, characterized by forming apertures
The above object has been attained by providing a production method of the above. Here, the easy-opening portion does not necessarily need to be in a completely open state, but is a small-diameter opening portion or a weakened portion, and a portion to be enlarged or opened by hot air suction processing or the like. Means

[0006]

In the surface material according to the present invention, the protruding openings are not formed extremely long, and the wall thickness thereof is substantially increased. Thus, the opening itself is not closed. Further, in the manufacturing method, by re-opening the thermoplastic resin film by the hot air suction process to the recess easy-opening portion, excessive extension of the protruding opening wall is prevented, which is sufficient for liquid permeation of body fluid. Create the opening diameter. For this reason, handling at the time of manufacture becomes easy.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the surface material of the absorbent article according to the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway perspective view of an absorbent article provided with a surface material according to the present invention, FIG.
Schematic illustration of apparatus for producing the surface material of the absorbent article according to the present invention, FIG. 3 is an enlarged view of the net mold used in the manufacturing apparatus of FIG. 2, FIGS. 4 (a) to (d) are line I-I Net money along
It is the schematic sectional drawing which showed the state of the recessed part of the thermoplastic resin film on a type | mold . As shown in FIG. 1, the surface material 2 of the absorbent article 1 according to the present invention has a point where a large number of recesses provided on the surface become protruding openings 5 for liquid permeation, and covers the absorber 4 to cover the skin. It is the same as the surface material of the conventional absorbent article in that it is in direct contact. As shown in FIG. 4D, the surface material 2 of the absorbent article 1 according to the present invention has a ratio L / D between the length L of the opening wall 5a and the opening diameter D of 1.
5 or less. To further explain the present invention, as shown in FIG. 1, an absorbent article 1 (sanitary napkin) includes a liquid-permeable surface material 2, a liquid-impermeable back material 3, and a material between these two materials 2 and 3. And the surface material 2 is composed of a large number of
The structure has a projecting opening 5.

[0008] The material of the surface material 2 is not particularly limited as long as it is a thermoplastic resin.
Examples include copolymers of olefins with other vinyl monomers such as acrylates and vinyl acetate, and hydrophobic thermoplastic resin sheets such as polyesters and polyamides. In particular, a polyolefin or a copolymer of an olefin and another monomer, or a polymer blend-based hydrophobic thermoplastic resin sheet is preferable in terms of texture and handling. In the present invention, polyolefin is used as the material of the surface material 2. The surface material 2 is preferably opaque. If it is opaque, the color of the liquid such as blood or urine can be blocked. Various means are conceivable as the means for making the material opaque.For example, a white pigment such as titanium oxide or zinc oxide, a calcium carbonate, or a filler such as clay alone or in combination with the above material as a coloring agent may be used in the molding process or the like. Can be added.

Although the thickness of the surface material 2 varies depending on the type of the absorbent article used, it is usually 0.01 to 0.05 mm, particularly preferably 0.02 to 0.03 m.
m. In the present invention, the thickness of the surface material 2 is 0.03 mm (measurement of thickness: KES FB texture evaluation system (Kato Tech Co., Ltd.), 0.15 gr / cm
² pressure). The surface material 2 has an uneven surface, and a liquid-permeable projecting opening 5 is formed in the concave portion as shown in FIG. The ratio L / D of the length L of the opening wall 5a to the diameter D of the opening is not more than 1.5 times, particularly preferably 0.8 to 1.2. Also, the opening diameter D
Is desirably 0.3 to 1 mm, particularly 0.5 to 0.7 mm. When the L / D ratio exceeds the above range, the opening wall 5a may be pressed during winding of the perforated film at the time of manufacture or during actual use thereof, and the opening 5 may be closed. On the other hand, if the opening diameter D exceeds the above range, there is a risk of liquid return, and if the opening diameter D is below the above range, sufficient liquid permeability cannot be exhibited. In this embodiment, L / D = 0.5 / 0.52
= 0.96 (measurement of D and L: measured by an enlarged photograph of the hole, D: narrowest place, L: longest place).

The thickness T of the opening wall of the protruding opening 5 for liquid permeation is desirably in the range of 1 to 3 times the thickness of the surface material 2. There is little blockage of the hole 5 and no uncomfortable feeling is given to the skin.
In this embodiment, the thickness of the opening wall 5a is about twice the thickness of the surface material 2. In the surface material 2, the distance between the openings 5, 5 is preferably set in the range of 0.05 mm to 5 mm, and more preferably in the range of 1 mm to 2 mm. Aperture density of the liquid transmissive opening 5 is limited to the liquid-permeable and liquid-return prevention properties, but 25 / cm ² to 40
It is preferably 0 / cm ² . That is, when the opening area (opening diameter D) is small and the opening density is small, the liquid permeability is substantially inferior, and as the opening area increases, the sheet formability deteriorates. 25 pieces / cm ²
It is preferable to set it to ４００400 / cm ² . The back material 3
Is not particularly limited as long as it has a leak-proof property of bodily fluids, but is preferably one having moisture permeability. Absorber 4
There is no particular limitation on the use of the body fluid as long as it has a body fluid absorbing ability, and a known body fluid is used.

In the surface material 2 of the absorbent article configured as described above, since the opening wall 5a is shorter than the opening diameter D as compared with the conventional surface material, the surface material 2 is opened when worn. 5 does not collapse and become inoperable. In addition, the skin has a good feeling of contact with the skin, absorbs body fluids quickly, and there is no danger of fluid return.

Next, the method for producing the surface material of the absorbent article according to the present invention will be described in detail. The method for producing a surface material of an absorbent article according to the present invention comprises providing a thermoplastic film with a large number of recesses and easy-opening portions in the recesses, performing a hot-air suction treatment on the easy-opening portions, The part is opened or expanded. The method for producing a surface material according to the present invention will be described in more detail.
FIG. 2 is a schematic explanatory view of a manufacturing apparatus in which the method for manufacturing a surface material according to the present invention is used. The manufacturing apparatus 10 circulates between a pair of rolls 11, 11, 11 in the direction of arrow A. Endless three-dimensional woven net mold conveyor 12
(A mold for forming a net-like surface material), a T-die 13 above the conveyor 12, and a suction nozzle 1 below the conveyor 12.
4, a hot air nozzle 15 for heat shrinkage below the conveyor 12, a hot air nozzle 16 for shaping holes above the conveyor 12, a suction nozzle 17 below the conveyor 12, and a winding roll 18 for surface material. .

In such a configuration, the thermoplastic resin is supplied from the T-die 13 to the surface of the conveyor 12 as a molten resin film 20a. The net mold conveyor 12 is shown in FIG.
As shown in FIG. 2, a 25-mesh wire having a substantially rhombic opening and a wire diameter of 0.35 mm is used.
Is 1.0 mm. Therefore, when the molten resin film 20a is Shidenobe casting onto conveyor 12 surface, by vacuum suction from the lower surface of the suction nozzle 14, Fig. 4
As shown in (a) and (b), a concave portion 5 ′ which is balloon-shaped or burst and opened is formed in the molten resin film 20 a.
At this time, the thickness of the film 20b is 0.03 mm, and as shown in FIG. 4 (b), the opening diameter D1 of the concave portion 5 'of the film is the film thickness of the interval P + the wire diameter -2 times the film thickness ≦ the opening diameter D1 <the interval P -Wire diameter, 0.59 mm ≤ opening diameter D
1 <0.75 mm. The length L1 of the recess wall at this time is 0.9 mm on average by measurement.

Next, heat is applied to the resin film 20b in which the concave portion 5 'is formed by a hot air nozzle 15 for heat contraction at the subsequent stage, and the wall of the concave portion 5' of the film 20b undergoes heat contraction. As a result, as shown in FIG.
0b is a film 20 having an easy-opening portion 6 formed in a concave portion 5 '.
c. The hot air temperature from the hot air nozzle for heat shrinkage is desirably in the range of 150 to 300 ° C., and the wind speed is desirably in the range of 10 to 50 m / s. In this embodiment, the hot air temperature is 230 ° C. and the wind speed is 15 m / s. The easy opening 6 is a so-called weak point such as a pinhole. In this embodiment, the easy opening 6 is a pinhole of 0.1 mm or less. Height is about 0.3 mm, and the contraction rate of the recess wall is 0.1
It is desirably in the range of 0.5 to 0.5.

[0015] Resin film 20 having easy opening 6 formed
c is a hot air nozzle 16 for shaping holes above the conveyor 12.
And the suction nozzle 17 below the conveyor 12 are processed almost simultaneously. Hot air nozzle 1 for shaping holes in this case
6 is 230 ° C., but a preferred range is 150 to 300 ° C., and the wind speed is 15 m / m
s, but a preferred range is 10 to 50 m / s.
It is. Further, the pressure reduction condition in the suction process of the suction nozzle 17 is desirably not less than -1000 mmHg. As a result, the perforated portion 6 is again enlarged and perforated, and the perforated film 20 as the surface material is formed with the length L and perforated diameter D of the perforated wall 5a as shown in FIG. The ratio L / D is 1.5 times or less, and in actual measurement, the opening diameter D is 0.52 m.
m, the length of the aperture wall 5a is 0.5 mm, and L / D =
0.5 / 0.52 = 0.96. Therefore, the aperture wall 5
The thickness a is (0.75-0.52) / 2, and the material 20 of the surface material 2 according to the present invention whose length is sufficiently short is obtained.

In the method of manufacturing the surface material of the absorbent article according to the present invention having the above-described structure, the opening of the concave portion 5 'once formed in the thermoplastic resin film 20 is shrunk by heating with hot air, and again, Since an appropriate opening wall 5a and an opening 5 having an opening diameter D can be formed by hot air and suction processing, the winding operation by the winding roll 18 at the time of manufacturing can be easily performed. Further, in the present manufacturing method, since a series of processing is performed from the molding of the resin film 20a on the same net mold conveyor 12, it is possible to suitably manufacture the surface material 2 even with a three-dimensional woven net mold. it can. That is, in the reheating opening method in which a hole is formed using a film as a base material, a new film base material is provided in a net mold. This is because a portion that cannot be brought into close contact with the mold is generated, and in the opening by the reheating method, the portion released from the mold is basically melted, but it is difficult to melt to an unnecessary portion.

In the above embodiment, one hot-air nozzle and one suction nozzle are provided for each process. However, the present invention is not limited to this, and a plurality of hot-air nozzles and suction nozzles may be provided. In addition, a plurality of units may be provided to repeat the heat shrinkage and the expansion process of the easily opened portion on the net mold conveyor. Further, in the above-described embodiment, the suction is performed by the suction nozzle from below the conveyor, but the blowing nozzle from above the conveyor may be used as an auxiliary or in place of the suction nozzle. Further, in the above embodiment, the net mold conveyor 12
The opening used a diamond-shaped thing, but it is not limited to this, and there is no problem if it is a shape according to the net knitting method,
For example, the shape may be an ellipse, a circle, a hexagon, or a parallelogram. Further, it is desirable that the interval P between the wires is in the range of 0.5 mm to 2 mm, particularly 0.8 mm to 1.3 mm, and if it is in this range, the opening diameter D of the surface material 2 is set to an appropriate size. it can. The thickness of the wire is desirably in the range of 0.2 mm to 0.6 mm. If the wire is too thick, it is difficult to make the opening 5 with a sufficient diameter. If the wire is too thin, the holding property of the molten film is deteriorated. .

[0018]

As described above, the surface material of the absorbent article according to the present invention does not substantially decrease the permeability of body fluids and has excellent skin contact feeling. Further, in the method for producing a surface material of an absorbent article according to the present invention, the surface material can be easily produced.

[Brief description of the drawings]

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

FIG. 2 is a schematic explanatory view of an apparatus for producing a surface material of an absorbent article according to the present invention.

FIG. 3 is an enlarged view of a net mold used in the manufacturing apparatus of FIG. 2;

4 (a) to (d) are schematic cross-sectional view showing a state of the recess of the thermoplastic resin film on the net mold along the line I-I.

FIG. 5 is a cross-sectional view when a conventional hole is formed.

[Explanation of symbols]

1 absorbent article 2 surface material 3 back sheet 4 absorber 5 protrudes (solid) opening 6 production apparatus of the easy opening 10 surface member 11 rolls 12 solid woven net die conveyors (type for surface material forming a net-like 13 T die 14 Suction nozzle 15 Hot air nozzle for heat shrinkage 16 Hot air nozzle for opening hole shaping 17 Suction nozzle 18 Winding roll 20 Thermoplastic resin film

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masako Asakawa 1892-1 Takada, Ninomiya-machi, Haga-gun, Tochigi Prefecture (56) References JP-A-62-257551 (JP, A) JP-A-4-15053 (JP, A) JP-A-1-249905 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61F 13/15

Claims (2)

(57) [Claims] 1. A molten resin film is placed on a surface material forming mold.
While supplying the molten resin film to the surface material forming mold.
Suction from below to form a large number of recesses in the molten resin film.
Once formed, and then heat shrink the recess to form the recess
Forming an easy-opening portion, and further forming the easy-opening portion on the surface material forming mold.
Hot air and suction are applied to the opening to open or expand the easy opening.
It features a large opening to form a protruding opening for liquid permeation.
A method for producing a surface material of an absorbent article. 2. The molten resin film has a net-like surface.
From the upper part of the material forming die onto the surface material forming die.
The method for producing a surface material of an absorbent article according to claim 1, wherein the surface material is formed.