JPS6152242B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a disposable diaper that is used once and then thrown away. Disposable diapers have recently become widely used because of their convenience. One of the significant deficiencies associated with conventional disposable diapers is leakage from the gap that occurs between the diaper and around the user's legs during use. This problem can be overcome to a large extent by making the diaper flexible or by using a diaper cover, etc. However, at present, disposable diapers are mainly made of paper, which is particularly difficult to absorb when wet. , diaper covers are reusable, and using a reusable cover with disposable diapers would contradict the purpose of disposable diapers, which should be discarded after one use. I end up. Therefore, in order to prevent this leakage from the armpits, it was considered that the diaper could be used in a geometric manner.
This is the so-called Z-fold, but compared to a flat one, it had a better fit and a larger absorption capacity, but it was not satisfactory in terms of leakage from the sides. Next, a diaper with elastic members inserted into the legs and gears on both sides was considered. It fits snugly around the user's legs and does not leave any gaps during use. However, because the elastic member is too tight to the leg, it may become stuffy or
The legs become irritated and turn red. Furthermore, in order to have high flexibility so that the gears can be placed on both sides of the diaper, the width of the central part of the absorbent layer is made narrower or thinner. absorption capacity decreases. Also, due to the nature of disposable diapers,
It has to be inexpensive, but since products containing this elastic member are made by pulling the elastic member,
Production efficiency also decreases, and manufacturing equipment becomes complicated, making it uneconomical and expensive. The next idea was to put water-absorbent shrinkable threads that contract when wet on both sides of the diaper, and cut the edges of both sides to fit around the user's legs. Unlike elastic members, this material does not tighten the user's legs from the beginning, but instead contracts when urinating and absorbing water, thereby preventing armpit leakage and causing less irritation to the user's legs. However, because the water-absorbing contraction thread gradually contracts, this method is only effective when the first urine volume is 30 to 40 c.c., and when the urine volume is 40 c.c. or more, it is only a small amount, but Leakage from the armpit was observed. As a result of further research, the present inventors discovered a disposable diaper that hardly leaks from the armpits, is comfortable for the user, and is economical, and completed the present invention. That is, the present invention comprises a fluid-permeable top sheet, a fluid-impermeable back sheet, and an absorbent layer inserted between these two sheets, and the absorbent layer has a 10% moisture content along the outside of both longitudinal edges of the absorbent layer. In a diaper in which a water-absorbing shrinkable thread that contracts in the above manner is fixed and installed in a diaper, the top sheet and back sheet that constitute both longitudinal edges of the diaper are folded back on the outside of the water-absorbing shrinkable thread, and the folded side edges are folded back. A disposable diaper is provided, characterized in that a bottom top sheet and an opposing top sheet are bonded together from the side edge of the absorbent layer to the inside to provide an adhesive portion. The invention will be explained in more detail below with reference to embodiments shown in the accompanying drawings. FIG. 1 is a partially cutaway plan view showing an example of a disposable diaper according to the present invention, and FIG.
It is an A-line sectional view. This diaper 10 consists of a top sheet 11, an absorbent layer 13, a moisture-resistant water-absorbing paper 12, a water-absorbing shrink yarn 14, and a back sheet 15. The absorbent layer 13 is overlaid on the backsheet 15 and has a plurality of adhesive lines 4 attached to the backsheet 15.
1 on the back sheet 15. In this example, the moisture-resistant water-absorbent paper 12 absorbs urine from the absorbent layer 1.
This is a preferred embodiment of the present invention, but it can also be omitted, or a cellulose fiber that can lead urine from the absorbent layer to the water-absorbing shrink thread 14 is a preferred embodiment of the present invention. if there is,
This can be appropriately placed at a position where the absorbent layer and the water-absorbing shrink yarn are connected. Cellulose fibers include flat and thread-like materials such as pulp, cotton, and rayon.
Although sheet-like materials such as paper and non-woven fabrics are included, water-absorbent paper is particularly preferred from the viewpoint of ease of handling, and moisture-resistant and water-absorbent paper with improved wet strength is particularly suitable. In FIGS. 1 and 2, the moisture-resistant water-absorbent paper 12 is stacked on the absorbent layer 13, its transverse dimension is longer than the absorbent layer 13, and it is placed along the outside of both longitudinal edges of the absorbent layer 13. It is arranged so as to overlap the water-absorbing contraction yarn 14. Generally, top sheet 11
The longitudinal and transverse dimensions of the sheet are longer than the absorbent layer 13 and the moisture-resistant water-absorbent paper 12, and are made to have the same dimensions as the back sheet 15, and are fixed to the moisture-resistant water-absorbent paper 12 by a plurality of adhesive lines 42 attached to the moisture-resistant water-absorbent paper 12. Furthermore, it is also fixed to the back sheet 15 by the protruding portions at both ends of the adhesive line 41. In FIG. 2, the water-absorbing and shrinkable threads 14 are installed on the backsheet 15, and both ends of the threads are fixed to the backsheet 15 with adhesive, for example, but the point is that the water-absorbing and shrinkable threads are fixed and installed on the diaper. When the water-absorbing contraction thread absorbs urine and contracts,
The legs of the diaper may be contracted to fit around the user's legs. The side edges of the back sheet 15 are covered with water-absorbing contraction threads 14.
The adhesives 16a and 16b are reloaded on the outer side.
, the opposing top sheets 17a, 1
7b is fixed, and spaces 18 are provided on both sides of the diaper. The adhesive part may be fixed only at approximately the center as shown in FIG. 1, or may be fixed over almost the entire length except at both ends. Furthermore, as shown in Fig. 3, incisions 31a, 31b, 32a, 3 are made on both side edges.
2b, and fold back the flaps 33a and 33b formed by cutting in the same way and apply adhesive 3.
4a and 34b may be used. The reason why you don't glue all the way to both ends is because if you glue it, you won't be able to adjust the torso, and the sides will be stiff, making it difficult to wear. The water-absorbing and shrinkable thread 14 may be provided over the entire length in the longitudinal direction, or may be short by saving the ends. Although FIG. 1 shows an example of the absorbing layer 13 having a rectangular shape, it may be modified. As the top sheet 11 used in the present invention, various nonwoven fabrics having liquid permeability are used.
A nonwoven fabric made of a single cotton or mixed cotton and mainly composed of pulp, rayon, polypropylene, polyethylene, polyester, etc. is used. Examples of the absorbent layer 13 include cotton-like pulp, water-absorbing paper, rayon cotton, and highly water-absorbing polymeric absorbent materials, which are used as a single layer or in a mixed or laminated form. The water-absorbing shrink yarn 14 is one that shrinks by 10% or more when wetted. Examples of water-absorbing shrink yarns that can be used include modified cellulose fibers such as cotton and rayon, such as carboxymethylated cotton, methylated cotton, etc. Cotton, ethylated cotton, hydroxyethylated cotton, sulfated cotton, sulfonated cotton, phosphorylated cotton, cationized cotton,
Amphoteric ionized cotton, acrylic acid, sodium acrylate, acrylic acid, acrylonitrile, acrylamide grafted onto cellulose fibers, and crosslinked products thereof, as well as the above-mentioned modified products of wool, silk, etc., and modified synthetic fibers, such as acrylonitrile. Threads made of fibers such as partially saponified fibers, partially maleated vinylon esters, and twisted yarns thereof can be mentioned. Among the above-mentioned yarns, twisted yarns obtained by combining an appropriate number of carboxymethylated cotton yarns and twisting them are preferable for use in the present invention. As the back sheet 15, a soft film such as a low density polyethylene film is generally used. It is also possible to use a product in which a few percent of titanium oxide is mixed with this to make it milky white, and the texture is improved by embossing or the like. When the diaper of the present invention is used, the supplied liquid is first absorbed through the top sheet and carried into the absorbent layer. It is preferable to use a nonwoven fabric made of hydrophobic fibers as the top sheet to prevent backflow, since it has spot absorbency and prevents leakage from spreading to the surrounding area other than where it leaked from the outside. When using moisture-resistant, water-absorbing paper, when the liquid reaches the moisture-resistant, water-absorbing paper, it is spread along the paper and further guided to the water-absorbing shrink yarns, but at the same time, it is absorbed over a wide range by the pulp in the absorbent layer. Furthermore, if a super absorbent polymer is contained in the absorbent layer, the liquid will also be absorbed by the polymer in the absorbent layer, and will not separate even under the pressure confined within the polymer. When the liquid reaches the water-absorbing and shrinkable threads located on the legs, the water-absorbing and shrinkable threads start to contract, and the legs of the diaper fit around the user's legs.
Prevents leakage from the armpits. However, as mentioned earlier, the water-absorbing shrinkable thread gradually shrinks, so if the first amount is 40 c.c. or more, even if you use the water-absorbing shrinkable thread, If it remains flat, there will be a small amount of armpit leakage. Therefore, it is first necessary to sufficiently wet the water-absorbing shrinkable yarn with the rapidly discharged liquid and to create a leak-free structure. In the present invention, in order to efficiently wet the water-absorbing shrinkable yarn, a space is provided to temporarily hold the liquid.
Here, it is desirable to provide a space by fixing the absorbent layer 5 mm or more and 20 mm or less from the side edge of the absorbent layer on the inner side. This is because if the distance is less than 5 mm, the effect of this space is less likely to occur, and if it is more than 20 mm, the surface that comes into contact with the user's skin becomes narrow. This space allows the liquid to be temporarily held, and at the same time the water-absorbing contraction yarn starts to contract due to the liquid, the liquid is absorbed into the internal absorbent layer. The absorption capacity of the diaper at this time is 30 ml of urine per time.
It is equivalent to ~80 c.c. In this state,
Even if the user continues to wear it, armpit leakage will not occur even when urinating two or three times. Furthermore, unlike the hourglass-type diaper that is often seen in diapers using elastic members, the diaper having such a structure according to the present invention does not have cuts on both side edges, so it is easy to manufacture and can be easily manufactured. , there is no need for disposal and it is economical. Also, unlike elastic members, it does not need to be manufactured in bulk, making it suitable for high-speed production. The present invention will be further explained in detail by showing Examples and Comparative Examples below. In addition, in the following Examples 1 to 2 and Comparative Example 1, the materials used are as follows. Top sheet: Non-woven fabric with a basis weight of 20g/ ^m2 made by mixing 50% polyester fiber and 50% polyethylene polypropylene composite fiber (Chitsuso Co., Ltd.) and bonding the fibers together by heat Moisture-resistant water-absorbing paper: Water absorption with a basis weight of 20g/ ^m2 Paper with improved wet strength using Kaimen water-soluble polyamide-epichlorohydrin resin from Hercules Co., Ltd. Absorbent layer: Pulp made by pulverizing SAM hydrophilic long-fiber pulp from Wehauser Co., Ltd. Water-absorbing shrink yarn: Carboxymethylated 20 count cotton thread Back sheet: A low-density polyethylene film that is generally commercially available for disposable diapers Example 1 As shown in Figure 1. We manufacture disposable diapers with the following composition, and provide diapers for 40 babies aged 5 to 18 months (7
~8 sheets/person, half male and half) were allowed to use it at night. At that time, the leakage rate and side leakage rate were measured. The results are shown in Table-1. The leakage rate in Table 1 indicates the percentage of diapers that leaked from any part of the diaper, not just the side. Example 2 A disposable diaper having the configuration shown in FIG. 3 was manufactured, and the leakage rate was measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 As shown in FIG. 4, a disposable diaper was manufactured in which the water-absorbing and shrinkable threads 14 were placed on the armpits and both edges were cut so as to fit around the armpits. The leakage rate was measured. Table 1 shows the results.
Shown below. Comparative Example 2 The leakage rate of a commercially available Z-fold disposable diaper was measured in the same manner as in Example 1. Table 1 shows the results.
Shown below. Comparative Example 3 The leakage rate was measured in the same manner as in Example 1 for a disposable diaper in which a commercially available elastic member was installed on the side. The results are shown in Table 1.

[Table] Total number of sheets used

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view of an embodiment of the disposable diaper of the present invention, Fig. 2 is a sectional view taken along the line AA, and Fig. 3 is a plan view of another embodiment of the disposable diaper of the present invention. 4 are plan views of the disposable diaper used in Comparative Example 1. 10...Disposable diaper, 11...Top sheet, 12...Moisture-resistant water-absorbing paper, 13...Absorbent layer, 14
...Water-absorbing contraction thread, 15...Back sheet, 16
a, 16b...Adhesive.

Claims (1)

[Claims] 1 Consisting of a fluid-permeable top sheet, a fluid-impermeable back sheet, and an absorbent layer inserted between these two sheets, water-absorbing shrink yarn that shrinks by 10% or more when wet is attached to both longitudinal edges of the absorbent layer. In a diaper that is fixedly installed between a top sheet and a back sheet along the outside of the diaper, the top sheet and back sheet that constitute both longitudinal edges of the diaper are turned back on the outside of the water-absorbing shrink yarn, and the side edges of the turned back sheets are A disposable diaper characterized in that a bottom top sheet and an opposing top sheet are bonded to each other from the side edges of the absorbent layer to the inside to provide an adhesive portion.