JPS61187855A - Absorbable 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 absorbent articles such as sanitary napkins and disposable diapers, and more specifically, to absorbent articles such as sanitary napkins and disposable diapers, and more specifically, as a leak-proof material, which is impermeable to human secretions and vapor permeable. The present invention relates to an absorbent article using a sheet material having excellent water repellency.

[Conventional technology]

Conventionally, absorbent articles such as sanitary napkins and disposable diapers have been equipped with a leak-proof material on the underside of the absorbent layer in order to prevent human body secretions such as menstrual blood and urine from leaking or seeping out of the absorbent article. is provided.

This leak-proof material is generally made of wet spunbond nonwoven fabric made of wet size paper or rayon, waterproof paper such as dry binder nonwoven fabric, and thermoplastic resin such as polyethylene, modified polyethylene, or ethylene-vinyl acetate copolymer. Laminated paper with films laminated together, or in some cases, the above-mentioned film itself has been used. Recently, it has also been proposed to use a porous film obtained by blending a filler and liquid rubber with a polyolefin resin and then subjecting it to a stretching process as a leakage preventive material.

[Problem that the invention seeks to solve]

However, when using an absorbent article while wearing it on the body, if human body secretions such as menstrual blood and urine are absorbed into the absorbent article, the secreted fluid in the absorbent article will increase until it is replaced. Although it may increase, it rarely decreases. In particular, when the above-mentioned laminated paper or film alone is used as the leak-proof material, the leak-proof material is located below the absorbent layer, so that human body secretions do not evaporate from the bottom surface of the absorbent article. Although it is possible for a small amount of human body secretion to evaporate from the surface of the absorbent article, the actual effect is hardly expected. Therefore, even if human body secretions absorbed into absorbent articles are vaporized by body temperature, most of them remain within the system! υ, users often felt stuffy or uncomfortable. Furthermore, the stuffiness that occurs during use can sometimes cause diseases such as rashes and inflammation. In general, the functions of comfortable leak-proof materials include moisture permeability and leak-proofing effect, and the moisture permeability of napkins is 0.5 t / 100 c.
ab2・Hr or more, 1t 7100 for diapers
0m"・Hr or more is required, and the leakage prevention effect is 70t/heap 2 or more for napkins and 1oo y for diapers.
/s2 or more (methods for measuring both will be described later), but the above-mentioned leakage preventive material does not have a particular moisture permeability function, which causes discomfort.

In addition, if a porous film made by blending filler and liquid rubber with polyolefin resin and then stretching the film is used as a leak-preventing material, the user's discomfort will be reduced and diseases such as rashes and inflammation will be prevented. Although this is unlikely to occur, it has been pointed out that there are manufacturing difficulties such as a high degree of control precision required during manufacturing and high costs.

Furthermore, when a single film or a porous film is used as a leakage preventive material, the film itself has no stiffness during the production of absorbent articles, making it difficult to fold or create tension. In some cases, vertical wrinkles tend to occur and remain on the product. Moreover, when using it, it makes a rustling sound, which makes it uncomfortable to use.

[Means for solving problems]

The present invention has been made to eliminate such conventional drawbacks and to provide an absorbent article that is more beneficial to users. The present invention relates to an absorbent article using a leak-proof material that is liquid-impermeable and vapor-permeable.

That is, the absorbent article of the present invention has an absorbent layer and a leak preventer provided below the absorbent layer, in which the leak preventer is a fibrous aggregate made of a porous base material and hydrophobic fibers. The fibrous aggregate has voids between the fibers, and the fibrous aggregate and the porous base material are integrated by welding the fibers at the points where they contact each other.

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

FIG. 1 is a plan view showing an embodiment of the leakage preventive material used in the absorbent article of the present invention, and FIG. 2 is a cross-sectional view taken along the line x-x'. The leak-proof material 2 is formed by integrating a porous base material 5 and a fibrous aggregate 6 made of hydrophobic fibers.

The fibrous aggregate 6 has gaps between adjacent fibers, as shown in an enlarged view in FIG. 1 to aid understanding. Therefore, human body secretions are prevented from passing through due to the hydrophobicity of the fibers and the leak-proofing effect of the porous base material, but steam can pass through the voids between the fibers and the pores of the porous base material. The porous substrate used in the present invention desirably has a certain degree of strength itself, and specifically includes paper, perforated film, knitted fabric, woven fabric, and nonwoven fabric. In this case, the porous base material does not need to be made of a single material, and a filler such as calcium carbonate may be mixed therein.

If at least the surface of these porous substrates is water-repellent treated with a sizing agent or the like, the effect will be even greater. Specifically, it is desirable that the leakage prevention effect is 30 f/cIa2 or more and the vapor permeation amount is 1 v/100-2·Hr or more.

Further, the fibers forming the fibrous aggregate are preferably hydrophobic fibers, and desirably thermoplastic or solvent-soluble fibers are suitable for the below-described integration method. Specific examples include polyethylene, polypropylene, polyester, nylon, ethylene propylene rubber, polyurethane, polybutadiene, high styrene,
Examples include vinylidene, polyvinyl chloride, acetate, and the like. The thickness of the fibers affects the size of the voids created between adjacent fibers, and is preferably 1 to 40 microns, with 3 to 40 microns being desirable.
~20 microns is preferably used. The weight of the fibrous aggregate itself does not require so-called stiffness, and if it is too large, it will affect the vapor permeability, so the weight should be 5 to 50.
t/m2, preferably 5 to 50 t/m2. A melting method or a solvent method is preferred as a method for integrating the porous base material and the fibrous aggregate.

The melting method is a method in which a hot-melt resin is melted by heating it to a temperature higher than its melting point, and then injected onto a porous substrate through a fine-hole nozzle. It solidifies and becomes integrated with the porous substrate. The solvent method is a method in which a resin is dissolved with a solvent, then sprayed onto a porous substrate with or without air as is commonly used, and then dried to remove the solvent.

By these methods, the porous base material and the fibrous aggregate are integrated over substantially the entire surface. At this time, any solvent may be used as long as it dissolves the fibers constituting the fibrous aggregate. However, tetrahydrofuran (THlF), dimethylformamide (DMF), toluene, acetate, hexane, ethyl acetate, etc. are recommended because of their ease of availability and handling.

As a method for integrating the porous base material and the fibrous aggregate, for example, a method using an adhesive or a method using heat embossing may also be used, but these methods do not have voids between the fibers, so the leakage prevention method of the present invention is not effective. Not suitable as a material. However, it cannot be prevented from using these methods together with the above-mentioned melting method or solvent method. That is, as shown in FIG. 3(a), a portion may be bonded with an adhesive 7, or a heat-sealed portion 8 may be provided in a portion by heat embossing as shown in FIG. 5(1)). However, in this case, considering the voids between fibers and the texture, it is desirable that the area to which adhesive or heat embossing is applied is 40% or less.

4 to 7 show various embodiments of the absorbent article of the present invention. Fig. 4 shows an example in which the absorbent article of the present invention is used as a sanitary napkin. It is covered with 1. An adhesive 4 is provided on the bottom layer for convenient attachment. In this case, the leakage preventive material 2 is the absorber 1-3
Although it also covers a part of the side surface and top surface of the absorbent layer 3, it is not necessary to do so, and it will be sufficient if the bottom surface of the absorbent layer 3 is covered. Fifth
A diagram substantially similar to FIG. 4 is shown in the figure. however,
In FIG. 4, the fibrous aggregate 6 is provided on the absorbent layer 3 side, whereas in FIG. 5, it is provided on the surface material 1 side. Another embodiment of the absorbent article of the present invention is shown in FIG. Not covered. Although this is mainly used for disposable diapers, it is natural that it can also be used for sanitary napkins having such a structure. FIG. 7 also shows a diagram similar to FIG. 6. However, while in FIG. 6 the fibrous aggregate 6 forms the bottom layer, in FIG. 7 it is in contact with the absorbent layer 3. This will serve as a part of enhancing the understanding of the present invention.

The following method was used to measure the leakage prevention effect and vapor permeation amount to confirm the effect of the present invention.

■ Leak prevention effect: Pulp 2T1 absorbent paper 1.2F on top of the test piece (leak prevention material),
A napkin model is constructed by placing 0.3 f of a liquid-absorbing polymer and 0.5 l of a surface material, and after absorbing 201 drops of defibrinated horse blood as a test liquid onto the napkin model, an upward load is applied.

The load was changed from 5t/aI#2 to 150t/Al#2 and the load was measured until leakage and bleeding from the back surface of the test piece were observed during sassettling. The measurements under the - condition were made for 3 minutes, and the load was increased one after another only when there was no leakage or smearing.

■ Vapor permeation f: The amount of permeation during the initial 1 hour was measured by applying TUB 20208. f / 100 儂2・Hr Example 1 (melting method) Various thermofusible resins shown in Table 1 were melted at a temperature higher than their melting points, and preheated with hot air at 300°C from a nozzle with a diameter of 0.5 m. The mixture was sprayed onto the porous base material shown in Table 1 to integrate the two to create a leakage preventive material. Note that the fiber diameter was adjusted by changing the hot air volume and discharge pressure, and the fibrous aggregate weight was adjusted by changing the injection time.

The evaluation results of the leakage prevention effect and the amount of vapor permeation are shown in Table 1. Note: Adhesion method: A: The fibrous aggregate itself is integrated with the porous base material.

B: Place adhesive (acrylic) Porosity applied at a fixed rate Integrating the fibrous aggregate into the base material I did〇 Example: B20% is the adhesive coated surface Show that the product is 20% O C: Fibrous aggregate as porous base material Heat a part after integrating it into Melted and integrated by embossing Ta0 Example = 010% is heat embossing space area is 10% shows.

Umbrella 2 Manufactured by Arayo Kagaku Kogyo @) Rosin sizing agent 3 Manufactured by Hamano Kogyo Co., Ltd. Rosin sizing agent Example 2 (solvent method) Various resins shown in Table 2 were mixed with 9 times the weight of T) (F or hasp spray gun) The mixture was discharged together with compressed air and dried to obtain a leak preventer material.The fiber diameter was adjusted by changing the amount of air and the discharge pressure, and the weight of the fibrous aggregate was adjusted by changing the injection time. Table 2 shows the planned results of leakage prevention effect and vapor permeation amount.

Comparative Example The same evaluation as in Example 1 or Example 2 was performed on a porous base material or a base material without holes in which the fibrous aggregate was not integrated. The results are shown in Table 3.

[Action and effect]

The absorbent article of the present invention uses a sheet formed by integrating a porous base material and a fibrous aggregate having voids between the fibers as a leakage preventive material, so that the absorbed human body secretions themselves are absorbed. Although it does not seep out through the leak-proof material, the vapor from the secreted liquid passes through the gaps between the fibers and the pores of the porous base material and evaporates out of the system, so it may leak during use. However, it is very easy to use, and it is. In particular, when a highly elastic resin such as nylon, ethylene propylene rubber, polyurethane, or 1.2 to polybutadiene is used as the fibrous aggregate, the friction coefficient of the fibrous aggregate becomes large.

Slippage between the absorbent layer and the leak-proof material or between the leak-proof material is significantly reduced, and effects are also observed in shape retention and leak prevention during use.

[Brief explanation of drawings]

Fig. 1 is a plan view showing one embodiment of the leakage preventive material of the present invention;
The figure is a sectional view taken along the line X-X', FIG. 5 is a sectional view showing another embodiment of the leak-proof material of the present invention, and FIGS. 4 and 5 show the absorbent article of the present invention used as a sanitary napkin. A schematic cross-sectional view showing an example of use. 6 and 7 are schematic cross-sectional views showing an example of the absorbent article of the present invention when used as a disposable diaper. 1: Liquid permeable surface material 2: Leak proof material 3: Absorbent layer 4: Adhesive (slip prevention or fixing tape) 5: Porous base material 6: Fibrous aggregate 7: Adhesive 8: Heat fusion part Applicant's representative: Furuya, Figure 1, Figure 3

Claims (1)

[Claims] 1. In an absorbent article having an absorbent layer and a leak preventer provided below the absorbent layer, the leak preventer is composed of a porous base material and a fibrous aggregate made of hydrophobic fibers. 1. An absorbent article characterized in that the fibrous aggregate has voids between the fibers, and the fibrous aggregate and the porous base material are integrated by welding the fibers at the portions where they come into contact.