JPH0690977A - Sheet-shaped absorbent - Google Patents

Abstract

PURPOSE: To enable to use for various products used in contact with the skin, for example, the products applied to the loins and groin including disposable diapers and sanitary napkins, by providing such characteristics as excellent elasticity and waterproofness and also being excellent in ventilation and flexible on the side of the unwoven cloth. CONSTITUTION: This sheet-type absorber has a elasticbody sheet 11 and unwoven cloth 12 which is pasted at least on one side of the elastic body sheet at the connection parts 13, continuously in the first direction and discontinuously in the second direction rectangular to the first direction. Said unwoven cloth 12 is longer than the elastic-body sheet in the intervals between the connection parts neighboring with each other, thereby multiple channels 14 extending in the first direction are formed between the elastic-body sheet, and thus a complex sheet is achieved. In the channels of this complex sheet, absorbers 15 are arranged, and the sheet-type absorber is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-shaped absorbent material that can be advantageously used for diapers and sanitary products, and more particularly, a sheet having excellent waterproofness and good touch and having an extremely large absorbing power. Shaped absorber.

[0002]

2. Description of the Related Art Sheet-shaped absorbers are widely used in diapers and sanitary products. Conventional absorbers generally
It has a structure in which a flat absorbent material is housed between a liquid-permeable topsheet and a liquid-impermeable backsheet, and the liquid to be absorbed passes through the topsheet, reaches the absorbent material, and is absorbed there. It is like this. Many materials have been proposed and put into practical use as the absorbent material.
Furthermore, with the development of a superabsorbent made of a polymeric substance capable of absorbing an amount of liquid up to 10 times its own volume, an absorber in which the superabsorbent is mixed with an absorbent material has been widely used. There is.

[0003]

The conventional sheet-like absorbent body, which has been proposed or put into practical use, has an absorption surface formed over the entire area in contact with the liquid in order to obtain a target liquid absorption capacity. It has a flat plate shape. Although such a flat plate-like absorbent material is satisfactory in terms of liquid absorption capacity, it lacks flexibility and therefore does not fit the body when worn, and a good usability cannot be obtained. In particular, when a superabsorbent is blended as an absorbent, since the superabsorbent has the property that the rigidity becomes extremely large when absorbing a liquid, the adhesion to the body is further reduced, and discomfort is reduced. Not only is it given, but it also causes defects such as side leakage.

An object of the present invention is to provide a sheet-shaped absorbent body having a sufficient liquid absorbing ability and exhibiting high flexibility such that it can be expanded and contracted according to a wearing condition, and therefore can be worn comfortably with high function. It is to be.

[0005]

According to the present invention, there is provided an elastic sheet and a composite sheet made of a non-woven fabric laminated on at least one surface of the elastic sheet. , Continuously in the first direction and discontinuously in the second direction orthogonal to this,
The non-woven fabric is bonded to the elastic sheet so as to have a predetermined space, a plurality of parallel channels extending in the first direction are formed, and an absorbent material is arranged in the channels. A sheet-shaped absorbent body is provided.

More specifically, in the composite sheet used in the present invention, an absorbent material having a large liquid absorbing capacity is arranged in a large number of channels formed between the elastic sheet and the nonwoven fabric. With this structure, the liquid permeates the non-woven fabric, enters the channel, and is absorbed by the absorbent material located in the channel.

As the absorbent to be seated in the channel, a hydrophilic material such as wood pulp or cotton, or a synthetic fiber material such as polypropylene or polyester, which is subjected to an appropriate hydrophilic treatment to impart hydrophilicity, is used. I can, but
Desirably, the so-called S. cerevisiae, which has the ability to absorb several tens of times its own weight of water or aqueous liquids. A. P. (SuperA
bsorbent polymer) is used.

The superabsorbent used in the present invention may be used directly in the form of particles, but in this case, the nonwoven fabric forming the wall of the channel should have a high filter function for preventing the particles from falling off. Will be needed. Therefore, the more preferable form of the super absorber is as follows. That is, a sheet obtained by cutting a sheet-like material obtained by compositing superabsorbent particles with wood pulp or a fiber web into an appropriate width, or a fibrous superabsorbent (for example, commercially available from Toyobo Co., Ltd.) There is a fiber bundle consisting of the product name "Lanceir"). Further, it is a web surface-coated with a superabsorbent obtained by impregnating a fibrous web with a monomer and then polymerizing and crosslinking the same, for example, a compressed composite made by Warehauser Co., which is slit into a band shape.

The absorbent material increases in volume by absorbing liquid. In particular, the superabsorbent has a significantly large difference in volume before and after absorbing the liquid. Therefore, if an absorber with a cross-sectional area that occupies most or all of the cross-section of the space inside the channel is arranged, the channel will expand in the cross-section direction by the amount of expansion of the superabsorber after absorption. However, since this expansion is absorbed mainly by the expansion of the elastic sheet, there is no problem. However, if the expansion during absorption is significant, such as in a superabsorbent, or if such dimensional changes are not desired, the cross-sectional area of the absorbent should not exceed the cross-sectional area of the channel during expansion. It is desirable to set to. Further, by arranging such a free space, the water swelling power of the absorber is not obstructed, so that the absorbent power of the absorber can be fully exerted.

In the sheet-shaped absorbent body of the present invention, when it is desired that a part of the absorbent surface has a larger absorption capacity than the other part, the absorbent material housed in the channel located in this part. Can be larger than the other parts. When partially changing the distribution of the absorbent material, it is desirable to change the cross section of the channel in which the absorbent material is accommodated, depending on the distribution. The sheet-shaped absorber having such a configuration is particularly suitable for a diaper for children or a sanitary napkin in which the liquid is concentratedly supplied to the central portion.

The sheet-like elastic body used in the sheet-like absorber of the present invention is a thin layer sheet of natural rubber, synthetic rubber or the like,
Polyurethane film, polyurethane meltblown nonwoven fabric, styrene butadiene, block polymer film, polyolefin elastomer film, EVA,
Ultra-low density LLDPE, ethylene / propylene elastomer, ethylene / methyl acrylate elastomer and other polyolefin elastomers alone or synthetic rubbers thereof, blends of styrene ethylene butadiene / styrene block polymer (SEBS), or polyurethane elastomers and polyolefin elastomers A coextruded film or the like is preferable.

Further, the nonwoven fabric used in the present invention is selected in consideration of firstly exhibiting the function as an absorber and secondly the function of forming a channel.

In order to exert the function of the absorbent body, it is necessary for the nonwoven fabric to secure the safety to the skin and at the same time have the permeability of the liquid. On the other hand, when considering the channel forming function, it is necessary to consider the bondability with the film, the maintainability of the shape of the channel, and the like.

Considering the above-mentioned first and second functions, for example, the following non-woven fabric is advantageously used. That is, polypropylene, polyester, a relatively hydrophobic synthetic fiber such as nylon, and hydrophilic fiber such as rayon, cotton, or a mixed fiber thereof, a dry method,
A non-woven fabric made by a method such as a spun bond method or a hydroentanglement method, which has a relatively small fiber fineness (denier) (preferably 5 d or less) and a small basis weight (preferably 5).
0 g / m ² or less) is used.

In the case of using a hydrophobic fiber such as polypropylene as a main component, it is preferable to treat the surface with a surfactant which is safe for the skin in order to impart liquid permeability. In the case of using a hydrophilic fiber such as rayon as a main component, a fiber having antibacterial properties that is safe for the skin, for example, commercially available Fujibo "Chitocel", for the purpose of preventing adverse effects on the skin due to high water content on the surface. It is also effective to use fibers such as "" and "chitopoly".

Table 1 shows a list of typical nonwoven fabrics used in the present invention. In particular, among them, No. 1 in Table 1 is a non-woven fabric having a high elongation in the width direction of the channel and a high strength, which is so-called high toughness. Nonwoven fabrics obtained by the hydroentangling method as shown in 3 are suitable.

Table 1 shows specific examples of the nonwoven fabric suitable for the present invention.

[0018]

[Table 1] Embodiments of the present invention will be described below with reference to the drawings.

[0019]

1 is a partial perspective view showing an example of a sheet-shaped absorbent body constructed according to the present invention, and FIG. 2 is an enlarged sectional view of a part thereof. In the figure, the elastic body 11 and the non-woven fabric 12 constituting the sheet-shaped absorbent body 10 are continuous in the first direction of the non-woven fabric 12, for example, the machine direction, continuously in a cross machine direction which is a second direction substantially orthogonal thereto. Are discontinuously connected to each other at a connecting line 13.
The width of the non-woven fabric 12 is wider than the width of the elastic sheet 11 between the two adjacent connecting lines 13 and 13, and as a result, a large number of the non-woven fabrics 12 extending in the machine direction are provided between the elastic sheet 11 and the non-woven fabric 12. The channel 14 is formed.

Further, in the channel 14, an absorbent material 15 obtained by cutting a sheet-shaped superabsorbent material into elongated strips is arranged so as to extend over substantially the entire length of the channel 14. The cross-sectional area of this absorbent material 15 is the channel 1
4 1/2 or less, for example 1 /
It is set to 5.

The sheet-shaped absorbent body 10 thus configured
Are used in such an orientation that the nonwoven fabric 12 is in contact with the liquid. For example, when the sheet-shaped absorbent body 10 is used as a diaper or a sanitary napkin, the nonwoven fabric 12 is used.
Functions as a top sheet facing the body, and the elastic sheet 11 functions as a liquid-impermeable back sheet that blocks the outflow of liquid.
Absorbed by 5.

FIG. 3 shows a sheet-shaped absorbent body 20 according to another embodiment of the present invention. In the sheet-shaped absorber 20 of this example,
Two types of channels 21 and 22 having different cross-sectional areas are formed, and the cross-sectional area of the first channel 21 located at the central portion A in the width direction of the sheet-shaped absorbent body 20 is at the side portions B located on both sides thereof. It is larger than the cross-sectional area of the channel 22 in which it is located. The first absorbent material 23 arranged in the first channel 21 having a large cross-sectional area has a larger cross-sectional area than the second absorbent material 24 arranged in the second channel 22 having a small cross-sectional area. have.

The sheet-shaped absorbent body 2 having the structure shown in FIG.
Since 0 has a higher absorbency in the central portion A than in other portions, 0 is particularly suitable for applications in which the liquid supply is concentrated in a narrow area in the central portion.

As in the sheet-shaped absorbent body 30 shown in FIG. 4, the channels 14 have the same size, but the first absorbent area having a large cross-sectional area is provided depending on the required absorbent capacity. Material 31 and second absorbent material 32 having a small cross-sectional area
Can be provided in an appropriate arrangement, and in this case as well, a sheet-shaped absorbent body particularly suitable for applications in which the liquid is concentratedly supplied in a narrow range can be obtained.

In all the sheet-like absorbent bodies shown in FIGS. 1 to 4, the channel structure, in its dry state (non-absorption state), effectively acts on the inflow and diffusion of air and water vapor in its lengthwise direction, In the wet state (absorption state), it acts on the liquid diffusion that causes the liquid that has flowed into it to move quickly in the lengthwise direction, so that the liquid is distributed to the entire absorber inside the channel in a short time and an efficient absorption capacity is obtained. Demonstrate.

The means for connecting the elastic sheet 11 and the non-woven fabric 12 so as to form the channel 14 is not particularly limited, and for example, the corrugated non-woven fabric 12 is superposed on the flat elastic sheet 11 and both are formed. Can be joined by any means such as an adhesive, ultrasonic fusion or thermocompression. The most preferable method is a method in which non-woven fabrics are piled up to complete the bonding during the manufacturing process of the elastic body sheet while the elastic body sheet has adhesiveness.

As another means of forming the channels, a method of forming the channels by utilizing the difference in the elongation between the machine direction and the cross machine direction of the nonwoven fabric is applicable. That is, the non-woven fabric is laid on at least one surface of the elastic sheet, continuously in the machine direction, discontinuously in the cross machine direction, and after being bonded at the joint portion, the composite sheet is subjected to the elastic limit of the non-woven fabric. It is possible to form a channel by making the width of the non-woven fabric wider than the width of the elastic body sheet between the joints by causing the non-woven fabric to permanently stretch by stretching it beyond the cross machine direction and then opening it. It is possible. Such a channel forming method is described in No. 1 of Table 1 above. 3 and No. A non-woven fabric having a significantly large elongation in the cross machine direction with respect to the machine direction, such as the non-woven fabric shown in FIG. 4, is suitable.

As means for arranging the absorber in the channel structure, when forming the channel as described above, the absorber is arranged between the elastic sheet and the non-woven fabric,
Next, the elastic sheet and the non-woven fabric may be joined together, but in order to arrange the absorber at an industrially accurate position, a mold 51 having a multi-row groove having a shape as shown in FIG. 5 or FIG.
Or 52 is used, and the nonwoven fabric 12 is pushed into the groove mechanically or by means of vacuum suction or the like, and then the method of joining the elastic sheet 11 and the nonwoven fabric 12 at the flat portion is applied. You can The mold shown in FIG. 5 has the same channel size and the same diameter of the absorber 15, and the mold shown in FIG. 6 has the same channel size and the same diameter as that of the absorber 15. Handle different cases.

[0029]

As described above, the sheet-shaped absorbent body of the present invention is continuously and unidirectionally formed on at least one surface of an elastic sheet having large elasticity and impermeability. Discontinuously provided in the joining direction in the orthogonal direction, a non-woven fabric laminated at the joint, between the non-woven fabric and the elastic sheet, to form a plurality of channels extending parallel to each other, the absorbent material in the channel. Since it has a conformation structure, it has excellent stretchability and waterproofness, and also has the characteristics that it has excellent breathability and flexibility on the non-woven fabric side. Therefore, it is most suitable for various products used particularly in contact with the skin, for example, products applied to the waist and crotch such as disposable diapers and sanitary napkins.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of a sheet-shaped absorber according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of the sheet-shaped absorber of FIG.

FIG. 3 is a sectional view of a sheet-shaped absorber according to another embodiment of the present invention.

FIG. 4 is a sectional view of a sheet-shaped absorber according to still another embodiment of the present invention.

FIG. 5 is a sectional view showing an example of a mold used for manufacturing a sheet-shaped absorbent body according to the present invention.

FIG. 6 is a cross-sectional view showing another example of the mold used for manufacturing the sheet-shaped absorbent body according to the present invention.

[Explanation of symbols]

 10, 20, 30 Sheet-shaped absorbent body 11 Elastic body 12 Nonwoven fabric 13 Bonding line 14 Channel 15 Absorbent material 23, 31 First absorbent body 24, 32 Second absorbent body

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D04H 1/42 P 7199-3B 2119-3B A41B 13/02 G

Claims (8)

[Claims] 1. An elastic sheet, and a composite sheet made of a non-woven fabric bonded to at least one surface of the elastic sheet, wherein the elastic sheet and the non-woven fabric are continuous in the first direction. Intentionally, the non-woven fabric is bonded to the elastic body sheet discontinuously in a second direction orthogonal to the first direction so as to have a predetermined clearance,
2. A sheet-shaped absorbent body, characterized in that a large number of parallel channels extending in the direction are formed, and an absorbent material is arranged in the channels. 2. The sheet-shaped absorber according to claim 1, wherein the absorber contains a super absorber. 3. The sheet-shaped absorber according to claim 1, wherein the absorber is a rod-shaped member obtained by shredding a sheet containing a superabsorbent. 4. The sheet-shaped absorbent body according to claim 1, wherein the absorbent material is a filament made of fibers of a super-absorbent body. 5. The cross-sectional area of the absorbent material is 1/2 or less of the cross-sectional area of the channel.
The sheet-shaped absorber according to. 6. The centrally located channel has a larger cross-sectional area than the channels located on either side thereof, and the cross-sectional area of the absorbent material seated within the channel having the larger cross-sectional area is: The sheet-shaped absorbent body according to claim 1, which is larger than a cross-sectional area of an absorbent material arranged in a channel having a small cross-sectional area. 7. A diaper constructed by using the sheet-shaped absorbent body according to claim 6. 8. A sanitary napkin configured by using the sheet-shaped absorbent body according to claim 6.