JPS6132672Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to a sanitary napkin with improved water absorption and diffusion properties, liquid retention properties, etc. (Prior art) Conventional sanitary napkins have a water-absorbing layer made of water-absorbing paper or absorbent cotton on the top layer facing the human body, but because the direction of the fibers of this material is irregular, menstrual blood, etc. It is locally absorbed in the center of the water absorption layer and tends to diffuse in a circular shape from the center. On the other hand, the shape of a sanitary napkin is vertically long, so if it is locally absorbed in the center and spread in a circular shape as in the past, even though there is still some absorption capacity in the longitudinal direction of the napkin, The width direction becomes saturated in a short time, and then the menstrual blood or the like flows back toward the human body or leaks from the sides. In addition, various proposals have been made to increase the density of the water absorption layer or to have a multilayer structure in order to increase absorption and diffusion efficiency, but all of these have improved water absorption and liquid retention in the thickness direction. However, since the direction of the fibers of the material remains disordered, menstrual blood, etc., is still locally absorbed and diffused in a circular shape, reaching saturation in a short time in the thickness and width directions, and therefore flowing toward the human body. It is not possible to completely prevent the phenomenon of backflow and leakage from the sides, and if the density is increased or the layer is thickened in this way, there is a disadvantage that the cushioning effect decreases and the discomfort increases. (Purpose of the invention) The present invention was made to solve these problems, and it increases the water absorption and diffusion efficiency in the longitudinal direction according to the vertically long shape of the sanitary napkin, allows it to be thinner overall, and The purpose of the present invention is to provide a sanitary napkin that has improved water absorption, liquid retention, and waterproofness, is soft to the touch, has high cushioning properties, and is comfortable to use. (Structure of the invention) The feature of this invention is that on top of the waterproof layer,
An auxiliary water-absorbing layer made of water-absorbing paper, a water-absorbing liquid-retaining layer made of a highly water-absorbing polymer, and a group of long fibers with small single filament fineness made by opening cellulose acetate fiber tow into a band shape, with the longitudinal direction of the fibers aligned in the longitudinal direction of the napkin. The sanitary napkin is constructed by sequentially laminating water absorbing and diffusing layers arranged densely in parallel and formed into cotton-like shapes, and wrapping the entire layer with a water-permeable covering material. (Example) An example of the present invention will be described with reference to the drawings. 1 is the waterproof layer, which is made of polyethylene film laminated paper that is wider than the napkin width.
An auxiliary water absorbing layer 2 made of multiple sheets of water absorbing paper stacked on top of each other is placed at the center in the width direction, and a water absorbing liquid retaining layer 2 made of GSP sheet (product name: Nippon Vilene Co., Ltd.) as a super absorbent polymer is placed on top of it. Put layer 3 on,
Both sides of the waterproof layer 1 are folded back to cover both sides of the upper surface of the water-absorbing liquid-retaining layer 3, and the auxiliary water-absorbing layer 2 and the water-absorbing liquid-retaining layer 3 are wrapped horizontally in the waterproof layer 1.
However, most of the center of the water-absorbing liquid-retaining layer 3 in the width direction is exposed on the upper surface. After that, on the water-absorbing liquid-retaining layer 3, a group of long fibers with small single filament fineness, which are made by opening cellulose acetate fiber tow into a band shape, are densely arranged with the longitudinal direction of the fibers parallel to the longitudinal direction of the napkin to form a cotton-like shape. The formed water absorption and diffusion layer 4 is placed thereon, and the whole is wrapped with a covering material 5 made of a polyester/rayon blended nonwoven fabric, and both sides of the covering material 5 in the width direction are rolled downward and partially overlapped. By crimping both ends in the longitudinal direction, a vertically long sanitary napkin is formed horizontally. The above-mentioned sanitary napkin is used with its upper surface, that is, the water absorption and diffusion layer 4 side facing the human body, and double-sided adhesive tape (not shown) is attached to the lower surface (unused surface) as a slip prevention piece in advance at a predetermined part. There is,
This double-sided adhesive tape is adhesively fixed to underwear or the like to prevent displacement. In this state of use, menstrual blood, etc. excreted from the human body is first absorbed into the water absorption and diffusion layer 4 through the covering material 5, and in this water absorption and diffusion layer 4, it is diffused in the longitudinal direction of the napkin due to the capillary action of the long fibers. The liquid is then absorbed and retained by the water-absorbing liquid-retaining layer 3. In this case, as the covering material 5, the above polyester/
By using a rayon blend nonwoven fabric, the feel is extremely good. The covering material 5 is not limited to the above-mentioned nonwoven fabric, but the same effect can be obtained by using a material mainly composed of nonwoven fabric, such as rayon nonwoven fabric or rayon paper laminated with cotton nonwoven fabric. In addition, as the water absorption and diffusion layer 4, a material is used in which a group of long fibers with small single filament fineness, which are formed by opening a tow of cellulose acetate fibers into a band shape, are arranged densely in the longitudinal direction of the napkin to form a cotton-like material. This makes it possible to improve water absorption and diffusion efficiency while providing excellent cushioning effects. In other words, cellulose acetate fiber is generally recognized as a hydrophobic fiber, but by opening the tow of cellulose acetate fiber into a band shape as described above, the single filament fineness can be reduced and the number of fibers per unit weight can be increased. The water absorption and diffusion layer can be greatly increased by forming a cotton-like structure by closely arranging long fibers with small single fiber fineness so that the longitudinal direction of the fibers is parallel to the longitudinal direction of the napkin. The number of fibers per unit volume in 4 can be greatly increased, and the gaps between each fiber can be made extremely small to greatly increase the number of gaps. These numerous fine gaps enhance the cushioning effect while exerting a strong capillary action, and at the same time, this strong capillary action absorbs menstrual blood, etc. that has passed through the dressing material 5, and at the same time, the napkin It can be quickly diffused in the longitudinal direction and efficiently absorbed while being diffused in an elliptical shape. Therefore, compared to the conventional case of absorbing and diffusing in a circular shape, the absorption and diffusion efficiency can be increased and the overall amount of water absorbed can be significantly increased. In particular, it is most effective to use cellulose acetate fibers with a single fiber fineness of 8 deniers or less and a total fiber count of 35,000 to 50,000 deniers as the water absorption and diffusion layer 4. This material has a high compression rate and can greatly improve the cushioning effect, and together with the texture of the covering material 5 mainly made of nonwoven fabric, it can provide an extremely good feeling of use. The amount of water absorbed per unit volume is increased compared to conventional water absorption layers made of pulp flaps such as water absorbent paper and absorbent cotton, and at the same time it is absorbed and diffused in the longitudinal direction by the strong capillary action created by the many fine gaps. , the overall water absorption can be further increased significantly. Note that cellulose acetate fibers recovered from cigarette filter plugs can also be advantageously used for the water absorption and diffusion layer 4. In addition, a mixture of cellulose acetate fiber and filament fiber may also be used. Next, the light blood and the like absorbed and diffused by the water absorption and diffusion layer 4 are absorbed and retained by the water absorption and liquid retention layer 3 that is in contact with the lower surface thereof. In this case, the water absorption diffusion layer 4
Menstrual blood, etc. absorbed in the water absorption and diffusion layer 4 are simultaneously absorbed by the water absorption and diffusion layer 4 and diffused by the aforementioned strong capillary action, thereby increasing the amount of water absorption. Since the inherent property of the material of the diffusion layer 4 is hydrophobic, its liquid retention capacity is smaller than that of the lower water-absorbing liquid-retaining layer 3, and the amount of water absorbed and liquid retained by the water-absorbing liquid-retaining layer 3 is small. is large, so
The menstrual blood, etc. is once absorbed by the water absorbing and diffusing layer 4 and quickly diffused in the longitudinal direction of the napkin, and then moves downward in the thickness direction of the napkin, where it is absorbed by the water absorbing liquid retaining layer 3, which has an even stronger water absorbing force. Therefore, it is quickly absorbed and retained in the water-absorbing liquid-retaining layer 3. In addition, since the water-absorbing liquid-retaining layer 3 is made of a water-absorbing polymer, when the water-absorbing liquid-retaining layer 3 absorbs menstrual blood, it immediately turns into a gel and retains the menstrual blood. Blood and the like do not flow back to the water absorption and diffusion layer 4 side, and menstrual blood and the like do not stay in the water absorption and diffusion layer 4, and most of it is absorbed and retained in the water absorption and liquid retention layer 3. After menstrual blood and the like are absorbed and diffused in the water absorption and diffusion layer 4 and absorbed and retained in the water absorption and liquid retention layer 3, the water absorption and diffusion layer 4 again performs the above-mentioned absorption and diffusion effect. By repeating the above action, the amount of liquid absorbed and retained by the water absorbing liquid retaining layer 3 can be increased.
In this case, by using the above-mentioned GSP sheet for the water-absorbing liquid-retaining layer 3, the amount of absorbed liquid-retaining material can be further increased. The above GSP sheet is produced by feeding flocculent pulp that has been thoroughly separated in a hammer mill and powder of alkali metal salt (GSP) of starch-polyacrylonitrile grout copolymer into a mixer at a predetermined weight ratio, and then stirring to create a uniform product. A mixture of 70 ± 12
GSP sheet is produced by forming a wet sheet with a weight of g/cm ² and integrally molding it into a sheet using wet heat compression bonding.This GSP sheet has extremely high water absorption and swells when it absorbs water. It has the property of becoming gel-like. When the water-absorbing liquid-retaining layer 3 made of a GSP sheet with such characteristics is used by stacking it on the lower surface of the water-absorbing and diffusing layer 4, the water-absorbing liquid absorbs and retains menstrual blood, etc. that have been absorbed by the water-absorbing and diffusing layer 4 and diffused in the longitudinal direction. Layer 3 allows rapid absorption over a wide area and greatly increases water absorption capacity. Also,
As mentioned above, the sheet absorbs water, swells, and becomes gel-like, so unlike conventional water-absorbing paper, which has a water-absorbing layer made of absorbent cotton, once absorbed menstrual blood, etc. remains in a liquid state in the water-absorbing layer, becoming saturated. Finally, there is no risk of it seeping out from the side edges of the napkin or flowing back into the human body. In other words, the liquid retaining properties for absorbed menstrual blood and the like are significantly improved. Note that the same effect can be obtained even if a sheet-like material mainly made of a superabsorbent polymer other than the GSP sheet is used as the water-absorbing liquid-retaining layer 3. On the other hand, the auxiliary water-absorbing layer 2 superimposed on the lower surface of the water-absorbing liquid-retaining layer 3 is provided as an auxiliary layer to ensure safety when the amount of menstrual blood etc. increases during the early period of menstruation or due to long-term use. Most of the water absorption and retention of menstrual blood, etc. is carried out by the water absorption diffusion layer 4 and water absorption liquid retention layer 3, so only a small amount of menstrual blood, etc. is absorbed by the auxiliary water absorption layer 2. Therefore, it is sufficient to use a plurality of layers of well-known water-absorbing paper for the auxiliary water-absorbing layer 2. Further, even if menstrual blood or the like passes through the water-absorbing liquid retaining layer 3 and the auxiliary water-absorbing layer 2, there is no risk of leakage to the outside because the waterproof layer 1 is provided at the bottom layer. Next, the water absorption amount and liquid retention amount (water retention amount) of the sanitary napkin will be considered. Experimental Example 1 A water absorption test was conducted using a sanitary napkin according to the present invention as a sample. The structure of the sample is as shown in the figure. The total weight was 5 g, and the proportions (% by weight) of each layer were as shown in Table 1.

[Table] The water absorption test method is based on the sanitary product standards (May 1960)
The test method according to the Japanese Pharmacopoeia (Ministry of Health and Welfare Notification No. 73, April 1973) specified in the standards and test methods of the Ministry of Health and Welfare Notification No. 285, April 24, 1971 was used. The test method is as follows. Place the sample on a 1680 micron (10 mesh) wire mesh with a known weight, with the side to be used facing up, and gently pour water over the entire surface with a beaker until the entire test area is completely absorbed, then continue pouring water until the water overflows. ,
After standing for 1 minute, it was weighed. The amount of water absorbed is the total weight of the sample after water absorption minus the weight of the sample before water absorption. The results are shown in Table 2.

[Table] Experimental Example 2 The sample in Example 1 above was the same as Experimental Example 1 above, except that the portions corresponding to the water absorption diffusion layer and water absorption liquid retention layer were replaced with water absorption paper having approximately the same weight. A water absorption test was conducted using the test method. The results are shown in Table 3.

[Table] According to the above experiments 1 and 2, sample No. based on the present invention.
It goes without saying that samples 1 to 5 all pass the standards for sanitary products, and the amount of water absorbed is dramatically higher than that of samples No. 6 to 10, which are blank products whose water absorption layer is formed only from water absorbent paper. It can be seen that it is increasing. Experimental Example 3 Samples Nos. 11 to 15 were prepared according to Table 1 above, and a water retention test was conducted. The test method is as follows. A perforated iron plate with 27 circular holes of 6 mm diameter drilled in a 3 mm thick iron plate was fitted into the bottom of a thin iron plate container with internal dimensions of 165 mm in length, 67 mm in width, and 50 mm in depth. A sample was placed, a thin iron plate of a size matching the container was placed on top of the sample, and in this state it was immersed in purified water adjusted to 25°±2°C and left for 5 minutes. Next, the sample was carefully taken out of the container, left for 2 minutes, and then weighed with a weight (base area 165 x 67 mm, weight 5436 g).
I placed it on it gently and waited for 1 minute. i.e. approximately 50
A load of g/cm ² was applied. After that, the weight was removed, the surrounding water droplets were gently wiped, and the weight was weighed. The water retention amount X is obtained by subtracting the weight C of the container (including the iron plate and thin iron plate) and the weight A of the sample from the weight B. X=B-C-A Water retention ratio=X/A The results are shown in Table 4.

[Table] Experimental Example 4 As a blank product, the sample shown in Table 1 above was obtained by replacing the portions corresponding to the water absorption diffusion layer and the water absorption liquid retention layer with water absorption paper having approximately the same weight as these, and A water retention test was conducted using the same test method as in Experimental Example 3 above. The results are shown in Table 5.

[Table] According to Experimental Examples 3 and 4 above, samples based on the present invention
It can be seen that samples Nos. 11 to 15 have a dramatically increased water retention amount compared to samples Nos. 16 to 20, which are blank products in which the water absorption layer is formed only from water absorption paper. (Effects of the invention) As explained above, according to the invention, a water absorption and diffusion layer is laminated on a water absorption and liquid retention layer made of a super absorbent polymer, and in particular, the water absorption and diffusion layer is made of cellulose acetate fiber. Since the tow is opened into a band shape and long fibers with small fineness are arranged densely in the longitudinal direction of the napkin to form a cotton-like shape, the number of fibers per unit volume in the water absorption and diffusion layer is reduced. In addition to greatly increasing the number of gaps between each fiber, the number of gaps can be greatly increased by minimizing the gaps between each fiber, and these many fine gaps improve the cushioning properties of the water absorption and diffusion layer while also creating strong capillary action. This increases the water absorption and diffusion efficiency in the longitudinal direction of the napkin, allowing it to absorb menstrual blood etc. very efficiently. Then, it is quickly absorbed into the water-absorbing liquid-retaining layer below, promoting the water-absorbing efficiency and liquid-retaining efficiency of the water-absorbing liquid-retaining layer, and greatly increasing the water absorption and liquid retention amount of the entire napkin. There is no risk of menstrual blood flowing back into the human body or leaking from the sides. Also,
Due to the synergistic effect of the improvement in absorption and diffusion efficiency per unit volume by the water absorption and diffusion layer and the improvement in water absorption and retention efficiency by the water absorption and liquid retention layer, the napkin can be made thinner overall, making it extremely convenient for packaging and carrying. It is convenient and
In addition, it is soft to the touch, rich in cushioning properties, and combined with the above-mentioned excellent water absorption, liquid retention, and leak-proofing properties, it provides an extremely good feeling of use.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the sanitary napkin according to the present invention in which the inner layers are disassembled, Fig. 2 is an external perspective view of the product, and Fig. 3 is a longitudinal sectional view taken along its width direction. . DESCRIPTION OF SYMBOLS 1...Waterproof layer, 2...Auxiliary water absorbing layer, 3...Water absorbing liquid retaining layer, 4...Water absorbing diffusion layer, 5...Coating material.

Claims (1)

[Scope of utility model registration request] On top of the waterproof layer, there is an auxiliary water-absorbing layer made of water-absorbing paper, a water-absorbing liquid-retaining layer made of super absorbent polymer, and a group of long fibers with small single filament fineness made by opening cellulose acetate fiber tow into a belt shape. A sanitary napkin characterized in that water absorbing and diffusing layers formed in a cotton-like manner are successively laminated in densely arranged parallel to the longitudinal direction of the napkin, and the entire layer is wrapped with a water-permeable covering material.