JPS62142556A - Body fluids absorbing article - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to body fluid absorbent articles such as sanitary napkins and disposable diapers. Specifically, the present invention relates to a body fluid absorbent article using a sheet impermeable to body fluids and permeable to vapor as a leak-proof sheet.

[Conventional technology and problems]

BACKGROUND ART Conventionally, body fluid absorbent articles such as sanitary napkins and disposable diapers are constructed by stacking a top sheet, an absorbent layer, and a leak-proof sheet, or by covering a leak-proof sheet and an absorbent layer with a top sheet. The leak-proof sheet has conventionally been made of synthetic resin films such as polyethylene, etc. in order to prevent body fluids such as menstrual blood, urine, and feces from leaking out.
So-called polylaminated waterproof paper, which is made by laminating a synthetic resin film such as polyethylene on a base of paper or nonwoven fabric, has been used. Since such leak-proof sheets have almost no vapor permeability, once body fluids are absorbed into the body fluid-absorbent article,
After that, although the amount of body fluid may increase, it hardly decreases due to transpiration. Therefore, if body fluids evaporate, it is only from the surface where the absorbent article is used, and the user often feels "stuffy" or discomfort due to increased humidity near the genitals and buttocks, and when using the absorbent article. The ``stuffiness'' of the skin may cause 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 in order to eliminate the drawbacks of these conventional body fluid absorbent articles and provide an absorbent article that is more beneficial to users.

That is, the present invention provides a body fluid-absorbent article having a body fluid-permeable top sheet, a body fluid-impermeable leak-proof sheet, and an absorbent layer disposed between both sheets, wherein the leak-proof sheet is made of sheet-like hydrophilic fibers. The present invention provides a body fluid absorbent article, which is a composite body in which at least one side of the base is coated with a hydrophobic polymer, and the hydrophobic polymer has penetrated into the sheet-like hydrophilic fiber base. be.

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

FIG. 1 is a perspective view of a sanitary napkin, which is an example of the body fluid absorbent article of the present invention, and FIG. 2 is a perspective view of a disposable diaper, which is another example of the body fluid absorbent article of the present invention. Also, the third
The figure is a sectional view taken along line A-A' in Figure 1, and Figure 4 is a cross-sectional view taken along line A-A' in Figure 2.
It is an A' line sectional view. The body fluid absorbent article 1 of the present invention is simply composed of a topsheet 3, an absorbent layer 8, and a leak-proof sheet 2, but the leak-proof sheet 2 is unique to the present invention. That is, the leak-proof sheet of the present invention has a hydrophobic polymer emulsion coated on at least one side of a sheet-like hydrophilic fiber base, and the hydrophobic polymer is infiltrated into the sheet-like hydrophilic fiber base. This is a moisture-permeable membrane manufactured by drying the polymer emulsion to compose 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, a hydrophobic polymer solution is treated with a liquid that is a non-solvent for the hydrophobic polymer but is freely miscible with the solvent of the hydrophobic polymer solution, and the polymer is coagulated to form fine pores in the membrane. It is a technology that However, it is extremely difficult to form uniform pores using this method.

On the other hand, there is a known technology in which a low-molecular substance, an inorganic salt, etc. are added in advance to a hydrophobic polymer solution, and after film formation, the polymer is eluted with a non-solvent solvent that can elute these additives to produce a moisture-permeable membrane. (Japanese Unexamined Patent Publication No. 48-19704, etc.). This technique requires an increase in additives in order to impart moisture permeability, and therefore has the drawback of reduced waterproofness. Furthermore, if these low-molecular substances and inorganic salts are uniformly mixed to form a film, it is extremely difficult to completely elute these substances, resulting in the disadvantage that it is difficult to obtain a homogeneous moisture-permeable film.

Traditionally, manufacturing moisture permeable membranes has the above drawbacks.
It required strict manufacturing conditions and complicated processes, and had poor productivity, so it was extremely unsatisfactory for use as a leak-proof sheet for body fluid absorbent articles.

The leak-proof sheet of the present invention is produced by coating a hydrophobic polymer emulsion on at least one side of a sheet-like hydrophilic fiber base and drying it, so that the hydrophobic polymer penetrates into the sheet-like hydrophilic fiber base. This is a moisture-permeable membrane having a structure in which the inter-fiber voids of a hydrophilic fiber base are covered with a hydrophobic polymer thin film. Unlike conventional techniques, this product is manufactured by a simple process of coating and drying, has excellent productivity, and can be fully used as a body fluid absorbent article.

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

In the present invention, as the hydrophilic fiber base, it is preferable to use an aggregate of water-absorbing fibers such as cellulose fibers such as wood pulp, rayon, and cotton. Specifically, paper, nonwoven fabric, and gauze are suitable, and paper that has been sized with consideration to waterproofness may also be used.

In the present invention, various hydrophobic polymers can be used, such as methyl (meth)acrylate,
Acrylic emulsions whose main components are (meth)acrylic esters such as ethyl (meth)acrylate and 2-ethylhexyl (meth)acrylate, or multiple (meth)acrylic esters, and styrene-butadiene rubber (STIR).
, carboxyl-modified SBR, nitrile-butadiene rubber (NBR), butadiene rubber (BR), and other synthetic rubber latexes, polyurethane emulsions in which polyurethane is dispersed in water, and synthetic resin emulsions such as vinylidene chloride latex.

These emulsions can be used alone or as a mixture of a plurality of emulsions.

Among these, particularly preferred hydrophobic polymers for the leakproof sheet of the body fluid absorbent article of the present invention are acrylic emulsion and synthetic rubber latex.

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

The above-mentioned hydrophobic polymer emulsion can be applied to a sheet-like hydrophilic fiber base using printing methods such as gravure printing and screen printing, kiss coater, roll coater, etc.
Known methods such as coating methods, spraying methods, etc. can be used.

It is also possible to use a combination of these methods. That is, any method that can uniformly apply the polymer emulsion may be used.

The coating amount of the polymer emulsion can be arbitrarily adjusted depending on the desired performance of moisture permeability and sea-proofing properties; the larger the coating amount, the higher the leak-proofing property, and the smaller the coating amount, the higher the moisture permeability. The coating amount that can be used for leakproof sheets for body fluid absorbent articles is generally 1 to 50 g/rrr.

Methods for drying the composite coated with the hydrophobic polymer emulsion include well-known methods, such as methods using hot air, infrared rays, electromagnetic radiation, steam, and the like. The drying temperature is not particularly limited as long as it is higher than the lowest film forming temperature of the emulsion. .

As described above, the leak-proof sheet of the present invention is a composite of a sheet-like hydrophilic fiber base (one side of which is coated with a hydrophobic polymer, and the hydrophobic polymer is a sheet-like hydrophilic group). It has a structure that penetrates into the base, and this structure provides the moisture permeability and water pressure resistance necessary for body fluid absorbent articles.

The leak-proof properties of body fluid-absorbent articles such as sanitary napkins and disposable diapers are satisfied if the leak-proof sheet has a water pressure resistance (JIS test method described below) of 50 cm or more (for long-term wear, water pressure resistance of 100 cm or more). cae or higher is preferred). In addition, the moisture permeability (JIS test method described below) value is 600 g.
/rrr・If it is more than 24 hours, it will cause "stuffiness" or "rash"
The preventive effect against

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

The top sheet 3 used in the present invention is not particularly limited as long as it is generally used in body fluid absorbent articles such as sanitary napkins and disposable diapers, but it is desirable that it has sufficient body fluid permeability. For example, nonwoven fabrics (dry or wet) made of single fibers or mixtures of bulb, racon, polyester, polypropylene fibers, etc. are suitable; specifically,
For example, 40% polyester fiber, 2% polypropylene fiber
A dry heat-bonded nonwoven fabric having a basis weight of 20 to 40 g/la'' and consisting of 0% polyethylene-polypropylene composite fiber and 40% polyethylene-polypropylene composite fiber is suitable.

Moreover, the absorption layer 8 used in the present invention is shown in FIGS. 3 and 4.
As shown in the figure, a combination of cotton-like pulp 5, absorbent paper 6, and superabsorbent polymer 7 is suitable, and one that has a fast absorption rate and a large amount of absorption is suitable.

〔Effect of the invention〕

The body fluid-absorbent article of the present invention is configured as described above and uses a leak-proof sheet that is impermeable to body fluids and permeable to vapor, and a portion of the body fluid passes through the leak-proof sheet and is not attached to the body fluid-absorbent article. Since it evaporates from the surface of use to the outside, the humidity in the vicinity of the genitals and buttocks decreases, which has the advantage of reducing stuffiness and discomfort during use. Furthermore, it is thought that ``rash'' and ``inflammation'' caused by ``swelling'' will be reduced. Furthermore, the moisture-permeable leak-proof sheet of the present invention has uniform flexibility and is excellent for use in body fluid-absorbing articles.

〔Example〕

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

Example 1 Using a hydrophilic base as shown in Table 1, various moisture permeable membranes as shown in Table 2 were manufactured.

As is clear from Table 1, the hydrophilic base used in the present invention originally has a fairly high moisture permeability, and the question is how to improve water pressure resistance without impairing this moisture permeability.
This is an important point in producing moisture permeable membranes.

As comparative products, polylaminated waterproof paper and polyethylene sheet, which are conventionally used in body fluid absorbent articles such as sanitary napkins and disposable diapers, are also shown.

Using the various moisture-permeable membranes listed in Table 2 as leak-proof sheets, body fluid absorbent articles as shown in FIGS. 1 and 2 were prototyped and tested for use. In the case of sanitary napkins, adult women use them for 2 to 8 hours, and the absorption capacity at that time is 1 to 8 hours.
It was 12g. In addition, in the case of disposable diapers, a 1 to 2 year old child uses them for 4 to 8 hours, and the absorption capacity at that time is 50 to 30
It was 0g. In either case, no oozing or leakage of menstrual blood or urine from the leak-proof sheet to the unused surface was observed, and it was confirmed that the sheet could be used comfortably without any ``rash.''

In contrast, conventional leak-proof sheets (comparison products in Table 2) had sufficient leak-proof properties, but when using disposable diapers,
A ``rash'' was observed, and ``swelling'' was also noted.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a sanitary napkin that is an example of the body fluid absorbent article of the present invention, FIG. 2 is a perspective view of a disposable diaper that is another example of the body fluid absorbent article of the present invention, and FIG. 1. FIG. 4 is a sectional view taken along line AA' in FIG. 2. 1... Body fluid absorbent article 2... Leak proof sheet 3... Top sheet 4... Rayon stable cotton 5... Cotton-like pulp 6... Absorbent paper 7... Super absorbent polymer 8... Absorbent layer 9... Anti-slip material Applicant Kaoru Furuya Figure 1 Figure 2 Figure 4

Claims (1)

[Scope of Claims] 1. A body fluid absorbent article having a body fluid-permeable top sheet, a body fluid-impermeable leak-proof sheet, and an absorbent layer disposed between both sheets, wherein the leak-proof sheet is a sheet-like hydrophilic sheet. 1. A body fluid-absorbing article characterized in that the article is a composite in which at least one side of a hydrophilic fiber base is coated with a hydrophobic polymer, and the hydrophobic polymer has penetrated into the sheet-like hydrophilic fiber base. 2. The body fluid absorbent article according to claim 1, wherein the hydrophobic polymer is selected from the group consisting of acrylic emulsion, synthetic rubber latex, polyurethane emulsion, and vinylidene chloride latex.