JPH0197202A - Disposable diaper - Google Patents

Abstract

PURPOSE: To obtain the subject diaper capable of enhancing the diffusibility of urine in the horizontal direction in a water absorbing layer and suppressing the wetting and returning properties of the urine by interposing a perforated sheet composed of a hydrophobic fibrous material having a specific porosity between a top sheet and the water absorbing layer. CONSTITUTION: This disposable diaper is obtained by interposing a perforated sheet 2 composed of a substantially hydrophobic fibrous material having through- holes 6, having about 3×10<-3> to 5cm<2> opening area and scattered at 3-40% porosity based on sheet area between a top sheet 1 composed of a water- permeable fibrous material and a water absorbing layer 3 composed of a water absorbing fibrous material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a disposable diaper that enhances the horizontal diffusion of urine within an absorbent layer and suppresses the rewetting property of urine.

[Conventional technology]

Disposable diapers have a wide variety of structures, but the disposable diapers used in boat fishing consist of: ■ A top sheet that comes into direct contact with the skin and allows urine to pass through; ■ A urine-absorbing layer made of cotton pulp, crepe paper, polymeric absorbent, etc. It is a laminated structure consisting of a waterproof bank sheet that prevents urine from leaking to the outside, and attached parts such as adhesive tape for wearing on the body and rubber bands for squeezing around the legs are attached to this laminated material. installed.

The water-absorbing layer made of cotton pulp, crepe paper, etc. itself has an excellent ability to absorb and retain urine in the vertical direction of the core layer, but has a poor ability to diffuse it in the horizontal direction. Therefore, when such a water absorbing layer is used immediately below the top sheet, the urine that permeates through the top sheet will be absorbed and retained within that area, but only in a very localized manner. do not have. When pressurization occurs, such as when the wearer's weight is applied to the water-absorbing and water-retaining portions of the water-absorbing layer, a rewetting phenomenon occurs in which urine retained in the hydrophilic fibers returns to the wearer's skin. In particular, after urinating several times, the amount of urine exceeds the absorption limit of the water-absorbing portion of the water-absorbing layer, resulting in even greater rewetting. Moreover, if the urine permeability of the topsheet is such that it can withstand several urinations, this phenomenon becomes even more pronounced since urine permeates through the same portion of the topsheet. As a result, the wearer's skin stays wet for a long time, causing discomfort to the wearer due to stiffness, and the decomposed products of urine irritate the wearer's skin, causing rough skin and other problems.
It is also a cause of skin disorders.

The same phenomenon as described above occurs when a polymer absorber is used alone or in combination with a pulp layer or the like in the water absorption layer.

[Problem that the invention seeks to solve]

As mentioned above, conventional disposable diapers have problems such as discomfort for the wearer and rough skin. An object of the present invention is to provide a disposable diaper that enhances the horizontal diffusion of urine to the core layer within the absorbent layer and suppresses the back-wetting of urine.

[Means for solving problems]

In the present invention, between the top sheet and the absorbent layer, about 3×10−
There are 3 through holes with an opening area of 5d per sheet area.
This invention relates to a disposable diaper characterized by interposing a perforated sheet with a porosity of 40%.

The perforated sheet that can be used in the present invention includes hydrophobic fiber materials such as polyolefins represented by polyethylene and polyvinyl chloride, and fiber materials having some water permeability obtained by subjecting these hydrophobic fibers to water permeability processing.

In addition to the perforated sheet, the disposable diaper according to the present invention further includes a hydrophobic fiber material sheet with hydrophilic properties between the top sheet made of a water permeable fiber material and the water absorption layer made of a water absorbent fiber material. Alternatively, a plurality of the perforated sheets may be interposed together with the other hydrophobic fiber material sheet.

The invention will be explained in more detail below with reference to the drawings, which represent embodiments according to the invention.

[Example and operation]

FIG. 1 is a partial view showing a laminated cross section of a disposable diaper according to the present invention. In FIG. 1, the diaper of the present invention includes a top sheet 1 that directly contacts the skin from above, and a perforated sheet 2.
, a back sheet 4 made of water-absorbing N3 and a waterproof sheet
are stacked in this order.

Examples of the perforated sheet 2 of the present invention include sheet-like materials made of waterproof materials such as polyolefin-based materials typified by polyethylene and vinyl-based materials typified by polyvinyl chloride. Furthermore, a film having some water permeability, such as a waterproof film treated with water permeability, can also be used. This is because the material of the film is hydrophobic, so even if it is slightly permeable, the effect of horizontally diffusing urine and suppressing wetting back as intended by the present invention is not lost.

The thickness of the perforated sheet 2 is not particularly limited, but if the sheet is thick, the diaper will feel hard and stiff when worn, resulting in poor wearing comfort. For this reason, this perforated sheet has a
A thickness of 500 tna is preferable, and a thickness of 10 to 500 tna is preferable.
A product with a thickness of 100 m provides better wearing comfort.

The perforated sheet 2 of the present invention has figures 2, 5, and 6.
A through hole 6 as shown in the figure is provided throughout. The area of the opening of the through hole 6 is approximately 3×10-”ad~5
d, and its porosity is 3 to 4 relative to the area of the perforated sheet 2.
It is 0%. That is, the porosity is expressed as -X100 (%), where A is the area of the perforated sheet of the present invention used for diapers, and B is the total area of the through holes in A.

When the opening area is large, it is preferable that the eight through holes 6 are evenly distributed on the perforated sheet 6. This is because if the through-holes 6 are locally concentrated, the diffusivity in that part will be inhibited, and the permeability of urine will be inhibited in other parts. However, in disposable diapers, there are fewer through holes in the parts where urine is less likely to pass through, that is, in the front and rear ends of the diaper.
Or it can be done without any problem. For example, this area can be approximately 10M both at the front and the rear. In this way, the arrangement of the through hole 6 is determined in relation to the size of the opening of the through hole 6.
Considering the horizontal diffusion range of urine that has passed through the top sheet 1 on the water absorption layer below the perforated sheet 2, the above-mentioned 3 to 40
% porosity and are appropriately scattered.

However, when the porosity of the perforated sheet 2 is less than 3%, the area of the non-perforated portion is large, and urine accumulates on the sheet, preventing the movement of urine from the top sheet 1 to the water absorption layer 3. The intended purpose of the invention is not achieved.

When the porosity exceeds 40% or when the area of one hole exceeds 5 d, the area in which the top sheet 1 and the water absorbing layer 3 are in direct contact is large, and the horizontal diffusion of urine is hindered. does not serve its purpose. Also, although it is related to the thickness of the perforated sheet, the area of one hole is approximately 3 Xl0-'co! If it is less than that, the pores will be too small to allow urine at a water pressure of 5N (normally, the water pressure for urination of 50cc is about 511W) to pass through immediately. Therefore, from the viewpoint of a balance between rapid permeability of urine into the water absorption layer 3 in the vertical direction and uniform diffusion in the horizontal direction, the opening area of the through hole 3 should be 1 to 5 CII! In that case,
Preferably, the porosity is in the range of 20-40%.

The shape of the through holes 6 in the perforated sheet is not particularly limited. circle(
Figure 1), ellipse, rectangle (Figure 5), stringy shape (Figure 6)
etc. - boat fishing. The perforated sheet 2 of the present invention also includes a sheet in which a plurality of long and thin films are arranged in parallel and used as one sheet, and an air seal sheet having air holes 5 as shown in FIG. It will be done. Even when using an air seal sheet, the thickness of the air seal sheet is 10~10 to maintain the softness when wearing a diaper.
500 voices, and the thickness of the air part is preferably 1 to 10 pieces. Examples of methods for producing a perforated sheet include a method of making holes by punching, a method of piercing with a needle-like object, and a method of making a slit and enlarging the slit in the horizontal direction.

By interposing the perforated sheet 2 having the above-mentioned conditions between the top sheet 1 and the water absorbing layer, the perforated sheet 2 can prevent urine from passing through the top sheet 1 from moving to the water absorbing layer 3. , which has the function of allowing urine to move vertically and at the same time spreading it horizontally. If urine is diffused horizontally, the utilization of the polymer absorbent material in the diaper will be increased and leakage back will be reduced.

FIG. 3 is a partial sectional view of another embodiment of the disposable diaper according to the present invention.

In FIG. 3, the top sheet 1 can be made of hydrophobic fibers treated with a hydrophilic finishing agent, as is conventional. However, if the topsheet lacks bulk, urine tends to spread horizontally onto the topsheet, thereby wetting the wearer's skin and causing discomfort to the wearer. Therefore, if the top sheet lacks bulkiness, that is, if the density is 0.05 g/- or more, a hydrophilic finishing agent may be added between the top sheet 1 and the perforated sheet 3.
．． It is necessary to suppress the diffusion of urine on the top sheet I by inserting a sheet 7 of low-density hydrophobic fibers attached at 05 to 2.0% by weight. Regarding this sheet-like material,
More specifically, the materials used include hydrophobic fibers such as polyethylene terephthalate, polypropylene,
Using polyacrylonitrile etc. or a composite fiber of these, single fiber fineness 1-10d, basis weight 5-100g/rr
r, a sheet-like material with a density of 0.005 to 0.55 g/ca is preferred. As for the manufacturing method, a hydrophilic finishing agent may be applied to carded cotton or the like by spraying or the like, and hydrophilic fibers such as crepe paper or a polymeric absorbent material may be used alone or in combination. A conventional waterproof backsheet made of polyethylene or the like is used under the water absorption layer 3. As described above, by interposing the hydrophilic low-density hydrophobic fibers between the top sheet 1 and the perforated sheet 2, urine permeation is carried out quickly and at the same time, the diffusivity is increased.

FIG. 4 is a partial sectional view showing another embodiment of the disposable diaper according to the present invention. In FIG. 4, a high-density hydrophobic fiber sheet-like material 8 further subjected to parent wood processing is placed between the perforated sheet 2 of FIG. It was established. According to this aspect, the urine permeated and diffused through the through holes of the perforated sheet 2 reaches the perforated sheet 2-1 via the hydrophilic high-density hydrophobic fiber sheet material 8, and the urine permeates and diffuses through the through-holes of the perforated sheet 2. The diffusion area of the core layer in the horizontal direction is further expanded on the water absorption layer 3 through the through hole 1, and the water absorption layer 3
Absorbed and retained by This makes it possible to fully utilize the water absorption layer 3 effectively. In this embodiment,
If the perforated sheet 2 and the perforated sheet 2-1 are installed so that the positions of the through holes are shifted between the two sheets, the horizontal diffusion of urine will be further increased, and this diaper will be approximately Since the entire surface is covered with a perforated sheet, the amount of wetness after urine is absorbed by the water absorption layer is extremely small.

In addition to the embodiment illustrated above, there is also a water-permeable sheet similar to the top sheet 1 between the perforated sheet 2 and the water-absorbing layer 3 shown in FIG. A sheet of synthetic fiber may also be inserted. The density of this sheet-like material is suitably 0.05 to 0.5 g/cffl. By inserting such a relatively high-density sheet-like material, it is possible to further reduce the wettability of urine after being retained in the water absorption layer.

According to the present invention, since a specific perforated sheet is used to increase the horizontal diffusion of urine, there is no need to temporarily retain urine with cotton-like pulp, and therefore the pulp layer can be changed from the conventional one. This can be significantly reduced or eliminated, and the polymeric water-absorbing layer can be used alone as the water-absorbing layer. Therefore, it is possible to provide a diaper that is more compact and lightweight than ever before.

[Urine permeation rate and diffusivity test]

A top sheet, a cotton-like material of hydrophobic fibers, and a specific perforated film according to the present invention were layered in this order, and the urine permeation rate and urine diffusivity were measured. The top sheet is made of polypropylene spunbond with a mesh size of 20 g/m and a hydrophilic finishing agent of 0.5 g/m.
% by weight was used. The hydrophobic fiber cotton was made by adhering 0.5% by weight of a hydrophilic finishing agent to ester carded cotton having a basis weight of 50 g/m and a density of 0.01 g/m. A polyethylene film with a thickness of 30 mm is used as the perforated film, and the opening area of the through holes is set to lXl0-'~10 (+
The porosity was varied from 1 to 50 (%) by IJ.

The experiment was conducted using a blank made of the same material as above except for the perforated film.

The urine permeation rate is 15aaX under a 15cm sample.
Same <15CIIIX15CI11 filter paper (Toyo Roshi 1
Three sheets of 1h 60) were stacked, and the water permeation rate at 20 mZ (the time until the special reflection of water droplets disappeared from the surface) was measured.

In this measurement, a permeation rate of 10 seconds or less is considered desirable.

The urine diffusivity was tested using the same sample and method as the urine permeation rate, and then the wet area of the filter paper surface was immediately measured. In this measurement, a diffusion area of 100 cal or more is considered desirable from the viewpoint of effective use of the water absorption layer and prevention of wetting back.

The results are shown in Table 1. The area of the above opening is 3 x 104 ~ 5
-1 When a perforated film with a porosity of 3 to 40% is used, urine passes through it quickly and has a high diffusivity.

When the above-mentioned opening area was 1X10-'', the permeation rate was extremely low regardless of the degree of porosity, so it was impossible to measure the diffusivity.

Table 1゜ *1 Water flowed and spilled, making measurement impossible.

〔Effect of the invention〕

The disposable diaper of the present invention has substantially hydrophobic pores between the top sheet and the water absorption layer, the opening area of the through holes being 3XlO-' to 5-1 and the porosity of 3 to 40%. Since the sheet is used, the horizontal diffusion of urine is increased without inhibiting the permeation of urine from the top sheet to the water absorption layer. Urine does not stay locally in the water-absorbing layer and is widely diffused within the water-absorbing layer, increasing the efficiency of using the water-absorbing material and reducing wetness, which reduces discomfort and rough skin for the wearer, making it more comfortable. , resulting in a hygienic diaper.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical sectional view of a first embodiment of a disposable diaper according to the present invention, FIG. 2 is a partial perspective view of a perforated sheet according to the present invention, and FIG. 3 is a partial longitudinal sectional view of a second embodiment of a disposable diaper according to the present invention. FIG. 4 is a partial longitudinal sectional view of a third embodiment of the disposable diaper according to the present invention, FIG. 5 is a plan view of another embodiment of the perforated sheet according to the present invention, and FIG. FIG. 7 is a plan view of another embodiment of the perforated sheet according to the invention. ■...Top sheet, 2...Perforated sheet,
3...Water absorption layer, 4...Back sheet, 5...Air hole, 6...Through hole, 7
．． 8...Hydrophilic hydrophobic fiber sheet material.

Claims (1)

[Claims] A perforated sheet made of a substantially hydrophobic fibrous material in which through-holes with an opening area of about 3 x 10^-^3 to 5 cm^2 are scattered at a porosity of 3 to 40% per sheet area is water permeable. 1. A disposable diaper comprising a top sheet made of a water-absorbing fiber material and a water-absorbing layer made of a water-absorbing fiber material.