JPH02168948A - Absorptive article - Google Patents

Abstract

PURPOSE:To improve the absorption performance of an absorber by forming at least a part of the absorber of a cellulose sponge and increasing the density of the cellulose sponge gradually from the upper layer to the lower layer. CONSTITUTION:A surface material 1 having the sufficient through-holes to allow the passage of moisture, such as bodily fluid, is used. While a leakproof material 2 can be constituted of paper subjected to a polyethylene lamination treatment, etc., or a non-woven fabric, etc., a porous material having moisture permeability is preferably used in order to prevent moistening. The density of the cellulose sponge sheet 4 constituting the absorber 3 is lowered toward the upper layer part. The bodily fluid is rapidly absorbed through the upper layer part of the small density into the absorber 3 in this way and is gradually penetrated and diffused into the lower layer of the large density. The bodily fluid is mainly held in the lower layer part of the large absorption capacity. The bodily fluid absorption rate of the above-mentioned absorber 3 is extremely high and since the absorbed bodily fluid is held in the lower layer part of the absorber 3, the reversion thereof is hardly generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to absorbent articles such as sanitary napkins and paper diapers that have a fast absorption rate and excellent anti-reversion effects.

C. Prior Art] Absorbent articles such as sanitary napkins and disposable diapers generally absorb bodily fluids excreted from the human body instantly to prevent them from leaking or causing discomfort to the human body. It is required to be able to absorb the absorbed body fluid and to be able to reliably retain the absorbed body fluid so that it will not flow back.

Therefore, conventionally, the materials constituting the above-mentioned absorbent body are
Are fluff pulp, absorbent paper, etc., which have excellent absorbency, used? Absorbent materials made of these materials are weak and may break or twist into clumps due to movement while being worn. It has been pointed out that this may result in leakage of menstrual blood and urine.

To solve this strength problem, use a cellulose sponge sheet with high strength as the absorbent material (for example,
(See Japanese Patent Application No. 12069/1983) Cellulose sponge sheets generally have better absorption speed and anti-return effect after absorption than conventional materials such as fluff valves. Because of their inferiority, they may cause discomfort to the user or cause leakage. Therefore, in order to effectively utilize the cellulose sponge sheet as an absorbent material, it is necessary to improve the absorption speed and the reversion prevention effect.

Problem to be Solved by the Invention J The object of the present invention is to improve the absorption rate of body fluids of the cellulose sponge sheet, the effect of preventing reversion after absorption, etc., thereby improving the absorbent body constructed using the cellulose sponge sheet. The purpose is to improve absorption performance.

[Means for solving the problem] Above, i! In order to solve the problem, the present invention provides an absorbent article having a liquid-permeable surface material, a liquid-impermeable leak-preventing material, and an absorbent body disposed between these two materials. At least a portion of the cellulose sponge sheet is formed of a cellulose sponge sheet, and the density of the cellulose sponge sheet is gradually increased from the upper layer to the lower layer.

[Function] When body fluid is excreted onto the absorbent body, the body fluid is quickly absorbed into the absorbent body through the low-density upper layer of the cellulose sponge sheet, permeates into the high-density lower layer, and diffuses. . Then, it is held in the lower layer portion, which has a large absorption capacity.

Therefore, the body fluid absorption rate of the absorbent body is very fast, and the absorbed body fluid is unlikely to return.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The absorbent article shown in FIG. 1 consists of a liquid-permeable surface material, a liquid-impermeable leak-proof material 2, and an absorbent body 3 disposed between the surface material I and the leak-proof material 2. It is made up of.

The absorbent body 3 is formed using a cellulose sponge sheet 4, and the sheet 4 is constructed such that its density gradually increases from the upper layer to the lower layer.

In this case, the range of the density difference is preferably 0.01 to 0.8 g/m2, and if it exceeds 0.8 g/m2, the flexibility of the product decreases, which may cause discomfort during use.

As a method for providing the cellulose sponge sheet 4 with density differences, as shown in FIG. 1, a plurality of sheet materials 4a, 4b, 4c? : Any method can be used, such as stacking the sheets one after another with the lower density on top, or giving a single sheet a partial density difference at the manufacturing stage.

Here, the above-mentioned cellulose sponge refers to a sponge made of a material having a cellulose skeleton, and examples thereof include sponges made of cellulose derivatives such as viscose, cellulose ethers, and cellulose esters, and sponges made of mixtures thereof. Coloring agents, additives, etc. are added to this as necessary.

Further, as the surface material 1, any material can be used as long as it has sufficient pores to allow water such as body fluids to pass through, such as rayon paper, nonwoven fabric, and a film with pores. etc. are preferably used.

On the other hand, the leakage preventive material 2 can be constructed of paper or nonwoven fabric treated with Botethylene lamination, or an appropriate synthetic resin sheet.

In order to prevent stuffiness, it is preferable to use a porous material that has moisture permeability.As such a moisture permeable and waterproof sheet, a thermoplastic synthetic resin sheet with a good texture, such as a polyolefin resin such as polyethylene or polypropylene, is preferable. A sheet that is highly filled with an inorganic filler to provide porosity and, if necessary, contains additives such as antistatic agents and lubricants, and is treated with ultraviolet rays or low-temperature plasma treatment. At least 1,000g/g/g of water, with a large number of micropores that allow water vapor to pass through but not water.
It is preferable to have a moisture permeability of m'・24h or more.

In the absorbent article having the above structure, when body fluid is excreted onto the absorbent body 3, the density of the cellulose sponge sheet 4 constituting the absorbent body 3 or the lower layer thereof is reduced, so that the body fluid has a density It is quickly absorbed into the absorbent body 3 through the small rising portion, and gradually permeates and diffuses into the lower layer where the density is higher. Then, it is mainly retained in the lower layer portion, which has a large absorption capacity. Therefore, the body fluid absorption rate of the absorbent body 3 is very fast4, and the absorbed body fluid is absorbed by the absorbent body 3.
Since it is held in the lower part of the body, it is difficult for it to return.

The absorbent body 3 may contain an absorption-swelling polymer to improve absorption performance, if necessary. Such polymers include, for example, carboxylated cellulose, acrylonitrile-crafted starch hydrolysates,
Examples include acrylic acid derivative polymers, polyaxolonitrile derivatives, and polyacryloamide compounds, among which acrylic acid derivative polymers are preferred.

Furthermore, the absorbent body 3 of the present invention uses one or more materials used in conventional absorbent articles, such as cotton-like valves and absorbent paper containing valves as a main component, in combination with the above-mentioned cellulose sponge sheet 4. It can also be configured as In this case, it goes without saying that the absorption-swelling polymer described above can be added as necessary. In the second embodiment shown in FIG. 2, the above-mentioned absorbent body 3 has a first absorption layer consisting of a cotton-like bulb 5 and a second absorption layer consisting of a cellulose sponge sheet 4 having a density difference between the upper and lower layers. The absorbent swellable polymer 6 is arranged between two absorbent layers, and an absorbent paper 7 is attached so as to wrap them.

Next, a performance test of the absorbent article according to the present invention will be explained.

(Test example) An absorbent body was constructed by sequentially stacking 81 sheets of viscose sponge material (thickness 1.5 mm) consisting of three sheets of viscose sponge with different densities, with the one with the lowest density on top, and the side surface of the absorbent body was Wrap the back side and part of the front side with leak-proof material, and further,
A sanitary napkin sample having a structure similar to that shown in FIG. 1 was prepared by covering the entire surface with a surface material made of nonwoven fabric, and the absorption rate and amount of reversion were measured. On the other hand, as a comparative example, similar measurements were performed on a sanitary napkin in which the density of the lower layer of the absorbent body made of a viscose sponge sheet was reduced. The results are shown in Table 1.

Table 1 Note that the above-mentioned absorption rate and reversion amount were measured by the following method.

8 g/cm
Simulated menstrual blood was passed through the cylinder with a pressure of
One oil was injected at once, and the time taken for the simulated menstrual blood to be absorbed on the sample surface was defined as the absorption rate.

<Return amount> Using the sample whose absorption rate was measured, place an NO12 filter paper on top of the sample and leave it for 2 minutes under a pressure of 50 g/cm, and then reverse the simulated menstrual blood amount transferred to the filter paper. Quantity.

As can be seen from the above results, when the density of the viscose sponge sheet constituting the absorbent body is smaller in the upper layer and larger in the lower layer, the absorption rate is higher and the amount of reversion is smaller.

[Effects of the Invention] As described above, according to the present invention, by configuring the cellulose-based trousers sheet constituting the absorbent body so that its density gradually increases from the upper layer to the lower layer, it is possible to increase the body fluid absorption rate and to increase the absorption rate of body fluids. It is possible to improve the effect of preventing body fluids from returning.

[Brief explanation of the drawing]

FIG. 51 is a sectional view showing the 81st embodiment of the absorbent article according to the present invention, and FIG. 24 is a sectional view of the second embodiment. 1. Surface material, 2. Leakage prevention material. 3. Absorbent material 4. Cellulose sponge sheet.

Claims (1)

[Claims] 1. In an absorbent article having a liquid-permeable surface material, a liquid-impermeable leakage prevention material, and an absorbent body disposed between these two materials, at least a portion of the absorbent body is made of a cellulose sponge sheet. 1. An absorbent article characterized in that the density of the cellulose sponge sheet is gradually increased from the upper layer to the lower layer.