JPH0614948B2 - Body fluid absorbent article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a body fluid absorbent article such as a sanitary napkin or a disposable diaper. Specifically, the present invention relates to a body fluid-absorbent article using a sheet that is impermeable to body fluid and has vapor permeability as a leak-proof sheet.

[Conventional technology and problems]

BACKGROUND ART Conventionally, body fluid absorbent articles such as sanitary napkins and disposable diapers have been constructed by superimposing a surface sheet, an absorbent layer and a leak preventive sheet, or by covering the leak preventive sheet and the absorbent layer with the surface sheet. As the leak-proof sheet, conventionally, a synthetic resin film such as polyethylene or the like in order to prevent leakage of body fluids such as menstrual blood, urine, and feces as its function,
So-called poly-laminate waterproof paper in which a synthetic resin film such as polyethylene is laminated on a base such as paper or nonwoven fabric has been used. Since such a leak-proof sheet has almost no vapor permeability, once the body fluid is absorbed in the body fluid-absorbing article,
After that, the amount of body fluid may increase, but it hardly decreases due to transpiration. Therefore, if the bodily fluid evaporates, it is only from the surface of use of the absorbent article, and the user often feels "unpleasantness" or discomfort because the humidity in the vicinity of the pubic area or buttocks increases. In some cases, "unevenness" causes diseases such as "rash" and "inflammation".

[Means for solving problems]

The present inventors have arrived at the present invention as a result of intensive research aimed at eliminating the drawbacks of these conventional body fluid absorbent articles and further providing a useful absorbent article to the user.

That is, the present invention is a bodily fluid-absorbent article having a body fluid-permeable surface sheet, a body fluid-impermeable leak-proof sheet, and an absorbent layer arranged between the sheets, wherein the leak-proof sheet is a sheet-like hydrophilic fiber. At least one side of the base is coated with a hydrophobic polymer, water pressure resistance (JIS L-1092) is 50 cm or more and moisture permeability (JIS Z-0208) is a composite of 600 g / m ² · 24 hr or more,
Disclosed is a body fluid absorbent article, wherein a hydrophobic polymer permeates a sheet-shaped hydrophilic fiber base.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a sanitary napkin showing an example of the body fluid absorbent article of the present invention, and FIG. 2 is a perspective view of a disposable diaper showing another example of the body fluid absorbent article of the present invention. Also, the third
FIG. 4 is a sectional view taken along the line AA ′ in FIG. 1, and FIG. 4 is a sectional view taken along the line A- in FIG.
It is an A'line sectional view. The bodily fluid-absorbent article 1 of the present invention is simply composed of the topsheet 3, the absorbent layer 8 and the leakproof sheet 2. The present invention is characterized by the leakproof sheet 2. That is, the leak-proof sheet of the present invention is obtained by coating an emulsion of a hydrophobic polymer on at least one side of a sheet-like hydrophilic fiber base, and in the state where the hydrophobic polymer has penetrated into the sheet-like hydrophilic fiber base. A moisture permeable membrane produced by drying the polymer emulsion to form a composite of a sheet-like hydrophilic fiber base and a hydrophobic polymer.

A wet film forming method is known as a method for manufacturing a moisture permeable film.
That is, the hydrophobic polymer solution is treated with a liquid that is a non-solvent for the hydrophobic polymer and is freely miscible with the solvent of the hydrophobic polymer solution, and the polymer is solidified to form fine pores in the membrane. It is a technology to do. However, it is extremely difficult to form uniform holes by this method.

On the other hand, there is a known technique for manufacturing a moisture-permeable membrane by adding a low-molecular substance or an inorganic salt to a hydrophobic polymer solution in advance and, after forming a film, eluting it with a solvent capable of eluting these additives with a non-solvent for the polymer. (JP-A-48-19704, etc.). With this technique, it is necessary to increase the amount of additives to impart moisture permeability, and thus there is a drawback that the waterproof property is lowered. Further, if these low molecular weight substances and inorganic salts are uniformly mixed and formed into a film, it becomes extremely difficult to completely elute these substances, and it is difficult to obtain a uniform moisture permeable film.

Conventionally, there are the above drawbacks in producing a moisture permeable membrane,
Since strict manufacturing conditions and complicated steps were required and the productivity was inferior, it was extremely insufficient to be used as a leak-proof sheet for body fluid absorbent articles.

The leak-proof sheet of the present invention comprises applying a hydrophobic polymer emulsion to at least one surface of a sheet-like hydrophilic fiber base and then drying it to allow the hydrophobic polymer to penetrate into the sheet-like hydrophilic fiber base. It is a moisture permeable membrane having a structure in which inter-fiber voids of a hydrophilic fiber base are covered with a hydrophobic polymer thin film. Unlike the conventional technology, this is manufactured by a simple process of coating and drying,
It is excellent in productivity and can be sufficiently used as a body fluid absorbent article.

The leak-proof sheet of the present invention is a moisture permeable membrane which is a composite of a hydrophilic fiber base and a hydrophobic polymer, and it is natural that the properties of both greatly influence the performance of the moisture permeable membrane.

In the present invention, the hydrophilic fiber base is preferably an aggregate of water-absorbent fibers such as cellulose fibers such as wood pulp, rayon and cotton. Specifically, paper, non-woven fabric, or gauze is suitable, and paper sized in consideration of waterproofness may be used.

In the present invention, various kinds of hydrophobic polymers can be used, for example, methyl (meth) acrylate,
Acrylic emulsions containing (meth) acrylic acid esters such as ethyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and multiple (meth) acrylic acid esters as main components, styrene-butadiene rubber (SBR), carboxyl Examples thereof include modified SBR, synthetic rubber latex such as nitrile / butadiene comb (NBR) and butadiene rubber (BR), polyurethane emulsion in which polyurethane is dispersed in water, and synthetic resin emulsion such as vinylidene chloride latex. These emulsions can be used alone or as a mixture of a plurality of emulsions. Of these, acrylic polymers and synthetic rubber latex are particularly preferable hydrophobic polymers for the leak-proof sheet of the body fluid absorbent article of the present invention.

The concentration of the emulsion is not particularly limited as long as it does not hinder the coating, but if it is less than 5% by weight, the time required for drying becomes long, so 7% by weight or more is suitable. .

As a method for applying the above hydrophobic polymer emulsion to the sheet-like hydrophilic fiber base, known printing methods such as gravure printing and screen printing, coating methods such as kiss coater and roll coater, and spray spraying methods are known. Is possible. It is also possible to use these methods in combination. That is, any method may be used as long as it can uniformly coat the polymer emulsion.

The coating amount of the polymer emulsion can be arbitrarily adjusted depending on the desired performance of moisture permeability and leakproof property. The higher the coating amount, the higher the leakproof property, and the smaller the amount, the higher the moisture permeability. The coating amount that can be used for the leak preventive sheet of the body fluid absorbent article is generally 1 to 50 g / m ² .

As a method for drying the composite coated with the hydrophobic polymer emulsion, a known method, for example, a method using hot air, infrared rays, electromagnetic radiation, steam or the like can be mentioned. The drying temperature is not particularly limited as long as it is higher than the minimum film forming temperature of the emulsion.

As described above, the leak-proof sheet of the present invention is a composite in which at least one surface of the sheet-length hydrophilic fiber base is coated with the hydrophobic polymer, and the hydrophobic polymer is the sheet-like hydrophilic fiber base. It has a structure that penetrates into the table, and this structure allows the body fluid-absorbent article to exhibit the necessary moisture permeability and water pressure resistance.

The leakproofness of body fluid absorbent articles such as sanitary napkins and disposable diapers is satisfied if the leakproof sheet has a water pressure resistance (JIS test method described below) of 50 cm or more (water pressure resistance of 100 cm when worn for a long time). The above is preferable). Further, if the value of the moisture permeability (JIS test method described later) is 600 g / m ² · 24 hr or more, the effect of preventing "smoothing" or "rash" is exhibited.

The leak-proof sheet of the present invention is produced under the conditions selected so as to satisfy the above contents (see Examples for details), and has body fluid impermeability and vapor permeability.

The topsheet 3 used in the present invention is not particularly limited as long as it is generally used for a body fluid absorbent article such as a sanitary napkin or a disposable diaper, but one having sufficient body fluid permeability is desirable. For example, a nonwoven fabric (dry type, wet type) made of a single or mixture of pulp, rayon, polyester, polypropylene fiber, etc. is suitable, and specifically,
For example, polyester fiber 40%, polypropylene fiber 20
%, A dry heat-bonded non-woven fabric having a basis weight of 20 to 40 g / m ² consisting of 40% polyethylene-polypropylene composite fiber is suitable.

The absorption layer 8 used in the present invention is shown in FIGS.
As shown in the figure, a combination of cotton-like pulp 5, absorbent paper 6 and superabsorbent polymer 7 is suitable, and one having a high absorption rate and a large absorption amount is suitable.

〔The invention's effect〕

The bodily fluid-absorbent article of the present invention is configured as described above, and uses a bodily fluid-impermeable, vapor-permeable leak-proof sheet, and a part of bodily fluid passes through the leak-proof sheet to prevent the non-absorption of the bodily fluid-absorbent article. Since it evaporates from the use surface side to the outside, there is an advantage that the humidity in the vicinity of the pubic area and the renal area is lowered, and the feeling of discomfort or discomfort during use is reduced. Furthermore, it is considered that the "rash" and "inflammation" caused by "unevenness" are also reduced. Further, the moisture-permeable leak-proof sheet of the present invention has uniform flexibility and is excellent as a material for use in body fluid-absorbing articles.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The invention is not limited to these examples only.

Example 1 By using the hydrophilic base as shown in Table 1, various moisture permeable membranes as shown in Table 2 were produced.

As is clear from Table 1, the hydrophilic base used in the present invention originally has a considerably large moisture permeability, and how to improve the water pressure resistance without impairing the moisture permeability is,
This is an important point in the production of moisture permeable membranes.

Incidentally, as a comparative product, a poly-laminate waterproof paper and a polyethylene sheet which have been conventionally used for body fluid absorbent articles such as sanitary napkins and disposable diapers are also shown.

Using the various moisture-permeable membranes illustrated in Table 2 as the leak-proof sheet, a body fluid-absorbent article as shown in FIG. 1 and FIG. 2 was prototyped, and a usage test was conducted. In the case of a sanitary napkin, an adult woman uses it for 2 to 8 hours, and the absorption amount is 1 to
It was 12 g. In the case of a disposable diaper, a 1-2 year old child used it for 4 to 8 hours, and the absorption capacity at that time was 50 to 300 g. In any case, it was confirmed that menstrual blood and urine did not seep or leak from the leak-proof sheet to the non-use surface, and that the product was used comfortably without "rash".

On the other hand, the conventional leak-proof sheet (comparative product of Table 2) had sufficient leak-proof property, but "rash" was observed when using disposable diapers, and "unevenness" was also pointed out.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sanitary napkin showing an example of the body fluid absorbent article of the present invention, and FIG. 2 is a perspective view of a disposable diaper showing another example of the body fluid absorbent article of the present invention. FIG. 3 is a sectional view taken along the line AA ′ of FIG. 1, and FIG. 4 is a sectional view taken along the line AA ′ of FIG. 1 …… Body fluid absorbent article 2 …… Leakage preventive sheet 3 …… Surface sheet 4 …… Rayon staple cotton 5 …… Cotton pulp 6 …… Absorbent paper 7 …… Super absorbent polymer 8 …… Absorbing layer 9 …… Anti-slip material

Claims (2)

[Claims] 1. A body fluid-absorbent article having a body fluid-permeable surface sheet, a body fluid-impermeable leak-proof sheet, and an absorbent layer disposed between the sheets, wherein the leak-proof sheet is a sheet-like hydrophilic fiber group. At least one side of the table is coated with a hydrophobic polymer, water pressure resistance (JIS L-1092) is 50 cm or more and moisture permeability
(JIS Z-0208) is a composite of 600g / m ² · 24hr or more,
A body fluid-absorbing article, wherein a hydrophobic polymer permeates a sheet-like hydrophilic fiber base. 2. The hydrophobic polymer is an acrylic emulsion,
The body fluid absorbent article according to claim 1, which is selected from the group consisting of synthetic rubber latex, polyurethane emulsion, and vinylidene chloride latex.