JPS61187854A - 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 having a function of preventing leakage of human body secretions. Regarding.

[Conventional technology]

Conventionally, absorbent articles such as sanitary napkins and disposable diapers have been devised in various ways to prevent human body secretions such as menstrual blood and urine from leaking out and seeping out of the absorbent articles. Ta.

A technique is generally used in which a liquid-impermeable leak-proof sheet is provided on a portion of the lower surface or side surface and upper surface of the absorbent layer. Although this technique is effective in some cases, it cannot be said to be sufficiently effective against leakage from the sides, a phenomenon called lateral leakage.

In order to increase the absorption capacity of the absorption layer, a technology was developed that applied water-absorbing polymers to the absorption layer, and the absorption capacity of the absorption layer itself was greatly improved. In addition, for sanitary napkins, adhesive tapes and the like have been developed for the purpose of fixing the napkin after it has been worn, and have a sufficient fixing effect to prevent side leakage due to misalignment of the napkin. However, these are only indirect measures, and more direct leakage prevention techniques are desired.

Japanese Patent Publication No. 59-39134 and Japanese Patent Publication No. 54-1476
As seen in Japanese Patent No. 95, there is a technique for preventing the diffusion of human body secretions between an absorbent layer, a liquid-permeable surface material, or both. However, these techniques are powerless against side leakage that often occurs due to diffusion within the surface material.

Moreover, a technique for covering a part of the surface material with a water-impermeable sheet is found in Japanese Utility Model Application Publication No. 55-75317. In this case, when using an absorbent article, moisture generated due to sweating from the skin will remain on the non-water permeable sheet, causing not only the user to feel stuffy or uncomfortable, but also a rash. New problems arise, such as the risk of causing diseases such as inflammation.

[Problem that the invention seeks to solve]

The main objective of the present invention is to prevent side leakage and seepage of absorbent articles. We will further explain side leakage of absorbent articles using sanitary napkins as an example.

General sanitary napkins, as shown in Figure 11(a),
A leak-proofing material 2 covers the lower surface, side surfaces, and part of the upper surface of the absorbent layer 3, and both are wrapped with a liquid-permeable surface material 1, and a tape 4 for preventing slipping is attached to the lowermost surface. There is. When using a sanitary napkin, as shown in Figure 11(b),
It is used with the center shaped like a chevron. Therefore, when the surface material 1 is a binder type using a conventional acrylic adhesive, the absorption speed is inferior, so that the menstrual blood 5 spreads over the upper surface of the surface material 1 5a-?, as shown in FIG. 11(1)). 5b, it often flowed and caused side leakage. However, recently, a surface material has been developed that has a high absorption rate and reduced surface wettability by using polyolefin fibers as the surface material. As a result, the menstrual blood 5 hardly flows on the surface of the surface material 10 as shown in FIG. Now absorbed. however,
If the menstrual blood retention capacity of the absorbent layer 3 is small or the menstrual blood propagation velocity is small, the menstrual blood 5 located directly under the surface material 1 will be pushed out to the surface, as shown in FIG. 12 (1)). The surface material 1 has to absorb it again, and the menstrual blood 5a that has been reabsorbed by the surface material spreads in various directions in the spaces between the fibers forming the surface material 1, causing side leakage and oozing. It is the cause of

In addition, the attached napkin does not remain flat,
As shown in FIG. 13(')#'(b), many wrinkles are generated on both sides of the long side, and grooves 6 are inevitably generated. Once formed, these grooves 6 do not return to their original planar shape; rather, when following changes in the shape of the crotch, the napkin folds at the grooves 6 and follows the changes.
There is a tendency for the groove 6 to increase further by 11. Therefore, menstrual blood also tends to leak from the groove 6, which is one of the causes of lateral leakage.

These causes are due to differences in human body secretions such as menstrual blood, urine, and soft stools, as well as differences in the shape of the crotch between the wearer (a woman and an infant) and the resulting pressure on the wearer. This is common to diapers.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems. That is, the absorbent article of the present invention has an absorbent layer and a liquid-permeable surface material located above the absorbent layer, in which the liquid-permeable surface material located at least at both upper ends of the absorbent layer is made of hydrophobic fibers. The fibrous aggregate has voids between the fibers, and the fibrous aggregate and the surface material are integrated by welding the fibers at the points where they contact each other. .

The absorbent article of the present invention will be described in detail below with reference to the drawings.6 Figures 1 and 2 show examples of the absorbent article of the present invention suitable for sanitary napkins. Naturally, this configuration can also be applied to disposable diapers.

The lower surface, both side surfaces, and both ends of the upper surface of the absorbent layer 3 are covered with a leakage preventive material 2, and the entire surface is covered with a surface material 1. A slip-preventing tape 4 is provided at the bottom layer. Fibrous aggregates 7 made of hydrophobic fibers are provided on the liquid-permeable surface material 1 located at both upper ends of the absorbent layer 3, and are integrated with the surface material 1 by welding of the fibrous aggregates. As is clear from FIG. 1, the fibrous aggregate 7 has many voids between the fibers.

The liquid-permeable surface material that can be used in the present invention is not otherwise specified, but non-woven fabric is preferable from the viewpoint of ease of acquisition, and the material for the non-woven fabric may be either a hydrophilic material such as rayon or a hydrophobic material such as polyolefin. But it's okay. Further, the manufacturing method is not limited to wet method, dry method, spunbond method, or punching method.

The fibers forming the fibrous aggregate must be hydrophobic, but preferably have thermoplasticity or solvent solubility in order to be suitable for the integration method described below. , urethane type, ester type, amide type,
A wide range of materials can be used, including vinyl acetate and acrylic. Specifically, polyethylene, polypropylene, polyester, nylon, ethylene vinyl acetate copolymer, polyurethane, polybutadiene, high styrene, vinylidene, ethylene propylene rubber, acetate, etc., as long as the resin can be jetted from a nozzle and can form a fibrous aggregate. Among the best materials, polyethylene, polypropylene, polyester, and ethylene-vinyl acetate copolymers are recommended from the viewpoint of cost and processability, and polyurethane, polybutadiene, and ethylene-propylene rubber, which have elasticity, are recommended because they are resistant to wrinkling. The thickness of the fibers affects the size of the voids that occur between adjacent fibers, and the smaller the voids, the better, so thin fibers are preferable. Considering the texture, 1 to 40 microns is preferable, and the More preferably, it is 5 to 20 km from the point. Furthermore, it does not prevent the use of water repellent treatment agents, clouding agents, pigments, etc. on the fibers.

The larger the amount of fibrous aggregates integrated into the liquid-permeable surface material, the better the side leakage prevention effect, so it is 5 to sat/m.
2 is preferred. Furthermore, although there is no limit to the width of the fibrous aggregate in principle, it is desirable that the width of the fibrous aggregate be 5 or more in order to have a good effect, and the width of one end should be one of the width of a sanitary napkin.
/3 is preferable since it is a receiving area for menstrual blood.

As a method for integrating the liquid-permeable surface material and the fibrous aggregate, a melting method or a solvent method is preferable. 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 multi-liquid permeable surface material using a fine-hole nozzle). It solidifies into a fibrous form and is integrated with the liquid-permeable surface material. The solvent method is a method in which the resin is dissolved with a solvent, then sprayed onto a liquid-permeable surface material with or without air as is commonly used, and then dried with scissors to remove the solvent. By these methods, the liquid-permeable surface material and the fibrous aggregate are integrated.

At this time, the solvent used may be any solvent as long as it dissolves the fibers constituting the fibrous aggregate, but tetrahydrofuran (THF)
), dimethylformamide (DM?), toluene, acetone, hexane, ethyl acetate, etc. are recommended.

There are also ways to integrate the liquid-permeable surface material and the fibrous aggregate, such as using adhesive or heat embossing! J), but these methods are not suitable for the present invention because they do not have voids between the fibers. However, it cannot be prevented from using these methods together with the above-mentioned melting method or solvent method, but in this case, considering the voids between fibers and the texture, the area where adhesive or heat embossing is applied should be 40% or less. It is desirable to do so.

Another embodiment is shown in FIG. This embodiment is almost the same as FIG. 2, but differs in that the fibrous aggregate 7 is also provided on the side of the sanitary napkin. The embodiment shown in FIG. 4 is more effective in preventing side leakage.

Still another embodiment is shown in FIGS. 5 and 6. Although these correspond to FIGS. 2 and 4, respectively, the fibrous aggregate 7 is also provided in the central portion forming the upper surface of the liquid-permeable surface material 1. The fibrous aggregate provided in this central part is
If hydrophobicity is imparted to the liquid-permeable surface material 1, it is not preferable to make the foot b1 thicker because it will hinder the liquid permeability.
/m2 is preferred.

FIG. 7 shows an example in which the absorbent article of the present invention is mainly applied to a disposable diaper. Of course, this configuration can also be applied to sanitary napkins. In this configuration, a leak preventive material 2 which is wider than the lower surface of the absorbent layer 3 is provided on the lower surface of the absorbent layer 5, and a liquid permeable surface material 1 is provided to cover the absorbent layer 3 and the leak preventer material 2. It is being If necessary, fixing tape or anti-scratch tape may be attached.

FIGS. 8, 9, and 10 show embodiments corresponding to FIGS. 4, 5, and 6. In FIG. 10 and FIG.
Although it is also provided above, the fibrous aggregate at this location can be omitted.

〔Example〕

Next, Examples and Comparative Examples will be shown to help improve understanding of the present invention.

The following methods were used to measure liquid diffusibility and leakage prevention to confirm the effects of the present invention.

(1) Diffusivity (applicable to the wicking Klemm test method) Cut test pieces with integrated fibrous aggregates under various conditions into 15 cys widths in the width direction when actually forming a napkin. Immerse the considered part in horse defibrinated blood as a reference, and use the side that is composed of the side that will be used (fibrous aggregate side).
Measure the suction distance after 10 minutes.

The result is better if the suction distance is short.

(2) Leakproofness ■ Base surface material of the test piece with integrated fibrous aggregate under conditions of 2 tons of pulp and 1.2 tons of absorbent paper? , liquid-absorbing polymer 0
．． Test napkins as shown in FIG. 2 or FIGS. 4 to 10 were produced using 3F as a basic material. After that, as shown in Figure 3, the test napkin was shaped like a chevron (90°
), and pour 10cc of defibrinated horse blood from the top of the
Also, under the actual mounting pressure of 50 t10s2, the amount was injected twice at 5QC/30 minutes, and after 1 hour in that state, the leakage from the side of the absorber was treated as lateral leakage. Observed.

Naturally, the result is that there is no side leakage.

The test was carried out on 10 points for each sample, and it shows how many of the 10 samples leaked horizontally. For example, 2/10 means that leakage occurred in 2 out of 10 samples.

■ Dynamic human body model evaluation Using the leak-proof sample, test sample 10 was set as shown in Figure 15 on the movable female waist model 8 as shown in Figure 14, and 1 hour after startup and 2 hours later. After a period of time, 5 tons of simulated blood was injected into each tube 9 for a total of 10 hours, and a total of 10 doses of simulated blood was injected into the tube 9 for dripping, and a total of 3 hours of pre- and post-seki (walking, D, D')
The test sample 10 was checked for leakage after repeating lateral opening and closing (directions c and c').

The test was carried out on 10 points for each sample, and it shows how many points out of the 10 samples leaked laterally.

Example 1 (melting method) The various heat-melting resins shown in Table 1 were melted at a temperature higher than their melting points, and then sprayed with hot air at 300°C onto a preheated nonwoven fabric from a nozzle with a diameter of Oju+ to integrate the two. The fiber diameter was adjusted by changing the amount of hot air and the discharge pressure, and the weight of the fibrous aggregate was adjusted by changing the injection time. In addition, the nonwoven fabric is shown in Figure 2, Figures 4 to 6 are Comparative Examples 6, and Figures 7 to 10 are &2.
I used the one from

The evaluation results are shown in Table 1.

Example 2 (solvent method) Various resins shown in Table 2 were dissolved in 9 times the weight of solvent, and 10
A heavy f% solution was prepared and discharged onto the nonwoven fabric together with compressed air using a spray gun, and dried to obtain a surface material. In addition,
The fiber diameter can be adjusted by changing the air volume and discharge pressure! 1ml
The weight of the fibrous aggregate was adjusted by changing the injection time. Moreover, the same nonwoven fabric as in Example 1 was used.

The evaluation results are shown in Table 2.

Comparative Example The same evaluation as in Example 1 or Example 2 was performed on various nonwoven fabrics in which the fibrous aggregates were not integrated. The results are shown in Table 3.

In the case of rayon-based conventional surface materials shown in Table 3,
Since the material itself is hydrophilic, it has high diffusivity (bleeding in the nonwoven fabric) and low leak-proofing properties, and lateral leakage was observed in 5 to 7 out of 10 points.

Compared to the non-containing type, better results have been obtained due to its diffusivity. However, in the leakproof test (1), 5 to 6 points of lateral leakage were observed because blood from inside the absorber was forced out through the surface material.

Also, since %A8 is completely hydrophobic, it has good diffusivity, but blood is not introduced from the surface material into the absorber and all of it flows on the surface.

In summary, conventional surface materials can quickly absorb menstrual blood.
In order to do this, it is designed to have sufficient space between the fibers and sufficient wettability at the same time.

Therefore, the diffusivity between the nonwoven fibers cannot be avoided, and blood is likely to be pushed out from inside the absorbent body due to changes in the shape of the crotch (specifically, when riding a bicycle, etc., which is the most severe condition). When the surface itself is absorbed, it is a space that passes through quickly, so it is easily pushed out to the surface. As this process is repeated, lateral leakage will occur from the sides attached to the chevron as shown in FIG. Since the space is large, the effect is extremely small.

In contrast to those comparative examples, the absorbent articles of the present invention are as shown in Table-1.
As shown in Figure 2, excellent leak-proofing properties were observed. These effects are not significantly affected by the resin, structure, weight of the fibrous aggregate, fiber diameter, thickness, bonding method, and additives.

The tabs are basically on the side where they will be used, at least on the side of the top layer (
Long side) An aggregate of hydrophobic fibers with a fiber diameter of 1 to 40 microns must be integrated at both ends at a rate of 5t/m2 or more.
Effective prevention of horizontal leakage can be achieved by forming leak-proof walls (structures) on both ends of the surface material that have unprecedented micro-spaces sufficient to prevent blood from being squeezed out from inside the absorbent body. According to the present invention, it is possible to maintain the characteristic that blood does not flow on a surface with a high absorption rate, which has been developed in the past, and to further prevent lateral leakage.

There is no problem in using adhesives or fusing as a bonding method, and also using various activator pigments as additives.

[Action and effect]

Since the absorbent article of the present invention has the above-described structure, as shown in FIG. However, since the fibrous aggregates 7 are welded to the surface material 1, the diffusion of human secretions in the surface material is small, and since the fibrous aggregates 7 are hydrophobic, there is no leakage from there. , which has a great effect on preventing side leakage.

Furthermore, since the fibrous aggregate has voids between the fibers, it has leakproof properties against human body secretions but does not impair breathability, and does not get stuffy during use, making it comfortable to use.

Furthermore, when the fibrous aggregate has elasticity, the structure shown in FIG. 13 (
As shown in a) and (1)), even during use, wrinkles do not form on the long sides, and from this point of view, it is also excellent in preventing side leakage.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the absorbent article of the present invention;
Fig. 2 is a sectional view taken along the line x-x' of Fig. 7, Fig. 5 is a transverse sectional view showing its lateral leakage prevention mechanism, and Figs. 4 to 10 are schematic diagrams showing other embodiments of the absorbent article of the present invention. FIG. Figure 11 shows an example of a conventional sanitary napkin.
(a) is a cross-sectional view showing the state before use, (b) is a cross-sectional model view of lateral leakage assuming the state of use, and Figure 12 shows an example of a conventional sanitary napkin with improved surface material. (a) is a cross-sectional model diagram with absorption characteristics similar to that in Figure 11 (1)), and (b) is a cross-sectional model diagram in which blood that has returned from the absorbent layer flows on the surface of the nonwoven fabric and causes horizontal leakage. Figure, 13th
The figures show the state of the napkin when worn, with (a) being a side view and (b) being a plan view. FIG. 14 is a perspective view of a movable female waist model, and FIG. 15 is a view of the model with a test sample installed. Brief explanation of symbols 1: Surface material 2: Leak proof material 3: Absorbent layer 4: Anti-slip tape 5: Blood 5a: Blood diffused on or partially in the surface material 5b: Blood 6 showing horizontal leakage : Groove formed on the side (long side) edge of the napkin 7: Fibrous aggregate 8: Movable female waist model 9: Tube for dripping simulated blood 10: Test sample Applicant's representative Kotani Furuya 1 Figure 3 Figure 4 Figure 4 Figure 7 Figure 6 Figure 11 Figure 12 b

Claims (1)

[Scope of Claims] 1. In an absorbent article having an absorbent layer and a liquid-permeable surface material located above the absorbent layer, at least the liquid-permeable surface material located at both upper ends of the absorbent layer is a fibrous material made of hydrophobic fibers. The fibrous aggregate has voids between the fibers,
An absorbent article characterized in that a fibrous aggregate and a surface material are integrated by welding the fibers at their contact points.