JP2000238161A - Absorbing laminate of disposable product and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbing laminate extremely reduced in thickness, hardly losing its shape after water absorption and capable of sufficiently developing absorbing capacity. SOLUTION: An absorbing laminate 1 contains no pulp fiber other than a nonwoven fabric and two nonwoven fabrics 10, 11 are bonded by reticulated layers 21, 22 comprising a hot-melt adhesive provided between the nonwoven fabrics and a water absorbable resin powder 31 is bonded to this hot-melt adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated body for absorbing disposable products such as disposable diapers and disposable pants, and a method for producing the same. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extremely thin absorbent laminate without resin dissipation and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as absorbents for absorbing body fluids used as disposable diapers, disposable pants or napkins, conventionally, defibrated pulp fibers, water-absorbent resin powders, thermoplastic fibers, etc. are formed into mats. Absorbent mats that have been wrapped and fixed with thin paper or the like have been used.

[0003] Such an absorption mat has a large thickness because it contains pulp fibers. Attempts have been made to heat-compress and form a thin shape by restraining it with thermoplastic fibers.However, the pulp fibers after absorbing water have a strong tendency to spread to the surroundings, and after all, after insufflation, inseams such as diapers etc. The portion swelled outward, giving the wearer discomfort.

On the other hand, attempts have been made to increase the amount of water-absorbent resin powder in order to improve the absorption performance of the absorber and reduce the thickness of the entire mat. Weight ratio) is the limit. That is, if the amount of the water-absorbent resin powder is further increased, the water-absorbent resin near the surface is pushed up by the lower water-absorbent resin due to swelling after water absorption (pulp fibers cannot restrain the movement of the water-absorbent resin). Inconveniences such as giving a discomfort to the wearer by projecting to the surface side of the body or breaking the water absorbent resin occur. In addition, since the amount of pulp fibers is small, the shape retention ability is inferior, and so-called wrinkling during wearing occurs.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an absorbent laminate having an ultra-thin form which does not lose its shape after absorbing water and which can sufficiently exhibit its absorption capacity, and a method for producing the same. Was.

[0006]

The absorbent laminate for a disposable product according to the present invention, which has solved the above-mentioned problems, is an absorbent laminate not containing pulp fibers other than a non-woven fabric, wherein two non-woven fabrics are disposed between the non-woven fabrics. It has a gist at the place where the water-absorbent resin powder is adhered to the hot melt adhesive while being bonded by the mesh layer made of the hot melt adhesive provided in the above.

By adopting this configuration, an ultra-thin absorbent laminate containing no pulp fiber could be provided.
In addition, since the water-absorbent resin powder is held in a state in which a part of the powder adheres to the network of the hot melt adhesive, it is present in a state of being trapped in the voids of the network, so that the water-absorbing resin powder can be reliably inserted between the nonwoven fabrics. And water absorption performance is not hindered by the adhesive.

The structure in which the two nonwoven fabrics of the absorbent laminate are partially welded to each other is a preferred embodiment of the present invention, and the shape stability of the absorbent laminate is further improved.

The method for producing the absorbent laminate of the present invention comprises:
By discharging the hot-melt adhesive in a molten state in a thread form from a plurality of nozzles toward the running belt-shaped nonwoven fabric surface, a network of the hot-melt adhesive is formed on the surface of the belt-shaped nonwoven fabric. Spray the water-absorbent resin powder on the top, again discharge the hot melt adhesive in the molten state in a thread form from the plurality of nozzles to form a network of the hot melt adhesive, and form a separate band-shaped nonwoven fabric thereon. It has a gist in that it is placed to form a continuous laminate and cut into a predetermined size. By employing this manufacturing method, the absorbent laminate of the present invention can be easily manufactured.

In the case of manufacturing the absorbent laminate according to claim 2, a step of partially welding the two nonwoven fabrics of the absorbent laminate before, simultaneously or after cutting into a predetermined size is performed. Add.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory cross-sectional view showing a typical embodiment of an absorbent laminate according to the present invention in an enlarged model. This absorbent laminate 1 comprises two nonwoven fabrics 10,
11, the reticulated body layer 2 of the hot-melt adhesive and the water-absorbent resin powders 31, 31. The two nonwoven fabrics 10 and 11 are adhered by a network layer 2 of a hot-melt adhesive, and the water-absorbing resin powder 3 is present in a state of being attached to the hot-melt adhesive constituting the network. I have. Therefore, the water-absorbent resin powder 31 is not in a state where the entire surface of the powder is covered with the adhesive, but is only partially attached to the net of the adhesive. Therefore, the water absorption performance is not hindered, and even if the powder 31 swells due to water absorption and becomes a large particle size as shown in FIG.
2) Since the mesh has voids, it can sufficiently exhibit water absorption performance. Further, it is more preferable to use a hot-melt adhesive of a type having excellent ductility, because the hot-melt adhesive can be extended so as to enlarge the mesh following the increase of the water-absorbing resin. Since these figures are modeled, the relative relationship among the thickness of the nonwoven fabric, the thickness of the mesh layer, and the size of the water-absorbent resin powder is as shown in this example. is not.

In the illustrated example, the mesh layer 2 is composed of an upper layer 21 and a lower layer 22. This is because when a manufacturing method described later is adopted, the water-absorbent resin powder exists near the center in the thickness direction. This results in a two-layer structure. This configuration is preferable because even if the water-absorbent resin powder swells after absorbing water, the influence does not affect the nonwoven fabric. It is more preferable to have three or more layers. However, if the hot melt layer between the nonwoven fabrics increases too much, the rigidity of the absorbent laminate may increase,
It is preferable to adopt a configuration in which the absorption laminate itself is laminated. In a configuration in which only one layer, that is, a water-absorbent resin powder is sprayed after forming a mesh layer of a hot-melt adhesive, and the upper non-woven fabric is overlapped, the water-absorbent resin powder and the upper non-woven fabric may come into contact with each other. The later swollen polymer protrudes,
Irregularities may be formed on the surface of the absorbent laminate,
It is not preferable because the adhesive strength of the nonwoven fabric may be weakened. In addition, since the water-absorbing resin may fall off, it is recommended that the number of reticulated layers be two or more.

As the nonwoven fabrics 10, 11, nonwoven fabrics made of polyolefin fibers such as polypropylene, rayon fibers, other synthetic fibers, and nonwoven fabrics produced by mixing silk, pulp (cellulose) fibers, and the like are used. Since the absorbent laminate of the present invention does not include pulp fibers other than non-woven fabric, a relatively bulky non-woven fabric is preferable to impart cushioning properties. As the nonwoven fabric 10 or 11,
It is also preferable to use a nonwoven fabric laminated in two or more layers from the viewpoint of providing cushioning properties. It should be noted that even a small amount of pulp fiber that does not increase the thickness of the absorbent laminate is included in the present invention.

As the hot melt adhesive, 60 to 1
The material is not particularly limited as long as it can melt at about 80 ° C. and form a net during cooling after being discharged in the form of a thread. The reticulated body refers to a state in which the hot melt adhesive is in a fibrous form, and the fibers are partially fused to each other to form a web. It may be discharged in a spiral form to form a net. By forming the net-like body, a large number of voids that can be retained even when the water-absorbent resin powder swells after absorbing water are formed. Further, even if the resin powder swells to a large particle size, the periphery of the swelled particles is entirely an adhesive, so that the particles do not fall off the adhesive net.

Specific examples of the hot melt adhesive include rubbers such as natural rubber, butyl rubber, and polyisoprene;
Styrene-based elastomers such as SIS, SBS, SIBS, SEBS, ethylene-vinyl acetate copolymer (EV
A), polyesters, acrylics, polyolefins and the like. In order to prevent the swelling particles from falling off after absorbing water, it is preferable that the particles have a strong adhesive force, and it is preferable that the particles have excellent ductility so that the mesh can be enlarged in accordance with the enlargement of the particles. In these respects, the use of rubber or styrene elastomer is recommended.

In order to form a hot-melt adhesive into a net-like body, a method (such as a curtain spray method or a spiral coating method) of discharging a molten adhesive from a plurality of nozzles in a thread form is preferred because it is simple. When the thread-like adhesive is laminated on the nonwoven fabric and solidified, a net-like body is formed. At this time, by blowing air onto the discharged adhesive, the adhesive can be naturally cut to an appropriate length by its own weight without intermittently discharging the adhesive. If the direction of the air is appropriately set, the net can be formed in a wide area.

As the water-absorbing resin powder, known water-absorbing resins can be used, and examples thereof include water-absorbing resins such as polyacrylates, celluloses, starch and acrylonitrile.
The higher the water absorption ratio, the better. This is because only the water-absorbing resin exerts the absorption capacity of the absorbent laminate of the present invention. The water-absorbent resin powder may be divided into a powder present portion and a non-existent portion, and is scattered only near the center of the absorbent laminate, is scattered mainly on the front side, or is scattered in a streak shape. The spray pattern can be changed as appropriate according to the gender of the wearer. Of course, it may be sprayed on the entire surface of the absorbent laminate. In the case of employing a configuration in which the water-absorbent resin powder is intermittently sprayed, the application site of the hot-melt adhesive can be matched with the spray pattern of the water-absorbent resin powder.

It is preferable that the periphery of the absorbent laminate is sealed by heat sealing or ultrasonic welding. This is to prevent the water-absorbent resin powder that has fallen from the hot-melt adhesive layer from spilling from around the absorbent laminate. However, when the water-absorbent resin powder is sprayed only near the center of the absorbent laminate, the surroundings may not be sealed. Furthermore, when used by incorporating into other products such as disposable pants, disposable diapers, sanitary shorts, etc., the periphery of the absorbent laminate may be sealed by the fixing work at the time of incorporation. The periphery may not be sealed as the absorbing laminate.

It is preferable that the absorbent laminate is partially welded with two nonwoven fabrics. When the water absorption is local, if only a part of the absorbent laminate swells and the weight increases, it is easy for the mold to lose its shape.However, if it is partially welded by heat sealing or ultrasonic welding, it will lose its shape. Less likely to wake up. As described above, in the case where the water-absorbent resin powder is intermittently sprayed to separate the powder-existing portion from the non-existing portion, it is preferable to heat-seal the non-powder-existing portion. This is because the seal strength tends to be low in the portion where the powder exists.

FIG. 3 is a cross-sectional view of the welded laminated laminate. The nonwoven fabrics 10 and 11 are welded at the welding portion 4, so that the mesh layer 2 of the hot melt adhesive and the water absorbent resin 31 are partitioned. This is shown in FIG.
3A is a cross-sectional view taken along the line AA of FIG. The welding shape is not particularly limited, and can be appropriately changed, such as an oblique lattice shape as shown in FIG. 4B and a circular dot shape as shown in FIG. Fig. 4
The heating may be performed using a heating plate or a roller having a tooth profile of the shape shown in FIG.

Next, a method for producing the absorbent laminate of the present invention will be described. FIG. 5 is an explanatory view of a preferred method for continuously producing the absorbent laminate of the present invention. First, a hot-melt adhesive in a molten state is discharged in a thread form from the coater 51 having a plurality of nozzles toward the surface of the band-shaped nonwoven fabric 12 running in the direction of the white arrow. The coater 51 has a length approximately equal to the width of the band-shaped nonwoven fabric 12, and may be one having a plurality of nozzles in the longitudinal direction. The air ejection port may be provided in the same body as or separately from the coater 51. Instead of the coater 51, a plurality of circular nozzles provided with a plurality of nozzles and an air ejection port may be provided so that the hot melt adhesive is applied in a planar shape. The hot-melt adhesive discharged in the form of a thread falls on the belt-shaped nonwoven fabric 12 to form the mesh layer 22.

Subsequently, the water-absorbing resin powder 31 is sprayed onto the mesh layer 22 of the hot melt adhesive on the belt-like nonwoven fabric 13 by the spraying device 52. The powder 31 is preferably sprayed before the hot melt adhesive is completely solidified, so that the powder 31 is firmly adhered to the mesh layer 22.

Next, in the same manner as in the step of forming the mesh layer 22 again, the hot melt adhesive in the molten state is
Is sprayed on to form a mesh layer 21.
Then, the continuous laminated body 15 is obtained by placing the separate band-shaped nonwoven fabric 13 thereon and pressing it with the rollers 54, 54.

When the continuous laminate 15 is cut into a predetermined size by a cutting device (not shown), an absorbent laminate is manufactured. When the welding step is added, the two nonwoven fabrics of the laminate are partially welded before, simultaneously with, or after the cutting step (or a combination thereof).
Welding can be performed by sandwiching the absorbent laminate with a heating plate or a roller having a tooth profile having the shape shown in FIG.

[0025]

As described above, according to the present invention, it is possible to provide an absorbent laminate which is excellent in water absorption performance even though it is ultra-thin, and has little deformation. Therefore, it can be used as an absorbent material such as disposable pants, disposable diapers, urine-absorbing pads, sanitary shorts, light incontinence shorts, etc., or used as it is as a sanitary napkin or pet sheet. It has become possible to provide a sanitary material which is excellent in inconvenience such as leakage and the like. In addition, the method for producing an absorbent laminate of the present invention is extremely simple, so that the absorbent laminate can be provided at low cost. The absorbent laminate of the present invention can be used for a water retention / water absorption material for agriculture, a concrete curing mat, a dew condensation prevention sheet, a poultice, a patch, a cosmetic, etc. in addition to the field of sanitary materials.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a typical embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of an absorbent laminate after absorbing water.

FIG. 3 is a schematic cross-sectional view of a welded laminated laminate.

FIGS. 4A, 4B and 4C are explanatory views showing examples of welding patterns.

FIG. 5 is a schematic explanatory view showing a typical example of the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorption laminated body 10, 11 Nonwoven fabric 12, 13 Strip-shaped nonwoven fabric 21, 22 Reticulated body layer of hot melt adhesive 31 Water absorbent resin powder 4 Welded part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3B029 BA02 BA04 BA12 BA14 BA15 BA18 BB06 BD16 BD17 4C003 AA26 AA28 GA02 4F100 AJ04A AJ04B AJ07 AK01C AK03 AK07 AK25 AK27 BA03 BA06 BA10A BA10B BA33 DE01C DG02 EC03 DG02 EC03 JD15 JD15C JL04

Claims (4)

[Claims] 1. An absorbent laminate containing no pulp fibers other than a non-woven fabric, wherein two non-woven fabrics are bonded by a mesh layer made of a hot melt adhesive provided between the non-woven fabrics. An absorbent laminate for disposable products, wherein a water-absorbent resin powder is attached to a hot melt adhesive. 2. The absorbent laminate according to claim 1, wherein the two nonwoven fabrics of the absorbent laminate are partially welded to each other. 3. The method for producing an absorbent laminate according to claim 1, wherein a hot-melt adhesive in a molten state is discharged in a thread form from a plurality of nozzles toward a running belt-shaped nonwoven fabric surface. Thereby, a network of the hot melt adhesive is formed on the surface of the belt-shaped nonwoven fabric, and then the water-absorbent resin powder is sprayed on the network, and the hot melt adhesive in a molten state is again formed into a thread from a plurality of nozzles. Discharging, forming a mesh of hot melt adhesive, placing a separate band-shaped nonwoven fabric thereon, forming a continuous laminate, and cutting the laminate into a predetermined size; Manufacturing method. 4. The method according to claim 3, further comprising the step of partially welding the two nonwoven fabrics of the absorbent laminate before, simultaneously or after cutting to a predetermined size.