JPS60185806A - Front and back leak prevented paper diaper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a paper diaper that contracts when it comes into contact with urine around the waist, thereby preventing so-called back and forth leakage.

[Technical background of the invention and its problems 1 Disposable diapers have better absorbency and water retention than general cloth diapers. However, the so-called side leakage and front and rear leakage problems associated with these disposable diapers have not yet been resolved.

Regarding side leakage, it is known to provide elastic contraction bands, such as rubber pant, around the sides, and this has actually been commercialized.

On the other hand, front-to-back leakage is a phenomenon in which when the wearer looks down on the floor, the tJI excretory fluid absorbed by the absorbent body is compressed and oozes out. In order to prevent this front and back leakage, methods have been proposed such as providing an elastic stretchable body around the waist, and interposing a water-impermeable plastic sheet between the two sheets described in 1i. ing.

However, with the former method, the waist is always tight, which causes discomfort to the wearer, and the shape of the product is not determined, making it difficult to package it smoothly and having a poor appearance. Moreover, the elastic body must be stretched once when worn, and even without this, children who are active need some getting used to wearing it. In addition, although the latter method has a certain effect, the material is plastic.
This type of waterproof piece increases the hardness around the waist and causes wrinkles in the body, which can pass between the wrinkles and the body and cause urine to urinate. may leak.

[Objective of the Invention 1] The present invention solves the above-mentioned conventional problems, and provides a front-to-back leak-proof city paper diaper that has excellent feel, excellent packaging properties and appearance, is easy to wear, and can reliably prevent front-to-back leakage. The purpose is to

[Summary of the Invention] To achieve the object 1, the present invention provides a paper diaper in which an absorbent body is covered with a water-permeable sheet and a water-impermeable sheet. The /l\ symbol is that a shrinkable piece mainly made of a belt-shaped polyvinyl alcohol-based dry nonwoven fabric that shrinks when it comes into contact with water is provided along the direction.

That is, the main points of the present invention that are different from the conventional example are as follows.

(1) Water-contact shrinkable material is provided around the waist.

Considering that there are two problems with providing elastic strips as in the conventional example, there is no tightening (=
The point is that it is made to contract only when urinating or when there is a possibility of back-and-forth leakage, and prevent back-and-forth leakage, without causing damage or irregularities in shape.

It is also possible to use the material according to the present invention for the parts around the legs, but it is generally not possible to adequately deal with side leakage due to speed etc., whereas front and rear leakage occurs relatively slowly (
For example, while sleeping), the functional material of the present invention can be optimally used. In addition, if the elastic band attached to the leg area is folded in half at the time of product production, the overall packaging shape will not be changed, but if such a band is attached to the waist area, the shape will be significantly distorted. The starting point of the present invention was to somehow solve this problem.

(2) The material is non-woven fabric. In terms of materials, conventional plastic sheet strips have a poor feel and place a heavy burden on sensitive infants. , the feeling of resistance disappears.

(3) The material is polyvinyl alcohol-based dry nonwoven fabric. Nonwoven fabrics made of so-called vinylon fibers are known, but they do not shrink on contact with water and are wet-laid nonwoven fabrics. The nonwoven fabric according to the present invention can reliably shrink upon contact with water, for example, by the manufacturing method described in the example below, and is relatively inexpensive.

[Specific example J of the invention The present invention will be explained in more detail below.

(Structural Example) First, an example of the paper diaper structure according to the present invention is shown in FIGS. 1 and 2. FIG.

1 is a water-impermeable sheet made of polyethylene or the like; 2 is a water-permeable sheet made of nonwoven fabric or the like that is generally used in this type of disposable diaper; 3 is an absorbent body containing cotton-like pulp or a polymer sheet encapsulated therein; 4 is absorber 3
5 is a fastening tape, and the structure thereof is basically known. be.

In the present invention, a band-shaped contraction piece 8 mainly made of a non-woven fabric for preventing front and back leakage is provided at least in a part of the waist area. In the illustrated example, it is provided on both the front part (lower part in FIG. 1) and the back part (upper part in FIG. 1) of the paper diaper, and over the entire 11 parts of the paper diaper. This shrinkable piece 6 is, for example, a water-permeable sheet! And/or it is fixed to the water-impermeable sheet 2 with a hot melt adhesive or the like in the entire area or in some parts thereof.

The shrinkable piece is mainly made of polyvinyl alcohol-based dry nonwoven fabric that shrinks upon contact with water.

Therefore, when a wearer puts on this disposable diaper and urinates, the urine that has been absorbed into the absorbent body 3 oozes out to the front or back part due to pressure on the floor and comes into contact with the shrinkable piece 6. 6 contracts, bringing that part of the disposable diaper into close contact with the wearer's skin, preventing leakage.

Here, the contraction pieces 6 may be arranged outwardly from the front and rear edges of the absorbent body 3, but in order to provide compression for contraction (and improve leakage prevention), 2. In a situation where at least a part of the absorbent body 3 is covered as shown in M, what should be done?
ff It's adorable. Of course, the contraction) 16 may be extended toward the water-impermeable cell 1 sheet l side, but the leakage prevention effect 11 is less effective. In addition, shrinkage J) 6 is the 1-2 surface (surface) of the water-permeable sheet 2.
Placing it closer to the bottom (back side) provides a better feel.

FIG. 3 shows an example in which a plurality of shrinkable pieces 13A and 6B are provided and are arranged on the waist circumference force side not over all 11 of the paper diaper but over some of the 11.

FIG. 4 shows leakage of an impermeable material 1 made of plastic film or the like between the impermeable sheet 1 and the water permeable sheet 2, which is arranged in the same manner as the shrinkable piece 6 in FIG. 2. Prevention 11 - Between the sheet 7 and the water-permeable sheet 2, or leakage.
A shrinkable piece 6G is fixed to the inner surface of the anti-slip sheet 7. In this case, even greater leakage prevention effects can be expected.

(Regarding the material of the shrinkable piece) The shrinkable piece of the present invention is mainly made of a polyvinyl alcohol-based dry nonwoven fabric that shrinks upon contact with water.

Although PVA fibers or so-called vinylon Ili materials made by acetalizing them are known, and it is also known to make them into non-woven fabrics, they are not dry non-woven fabrics that shrink upon contact with water.

An example of the nonwoven fabric of the present invention will be explained. First, known polyvinyl alcohol (PVA) is used as a starting material, dissolved in water with heating if necessary to make a 14-1B% aqueous solution, discharged and defoamed, and then dry-spun using a 30-50% aqueous solution as a stock solution. I do. The process up to this point is basically the same as the vinylon fiber manufacturing process. Then 220-230
Dry stretching is carried out in hot air of 'C, and then heat treatment is performed for several minutes at a Pv^ secondary transition point of 100 to 230°C. After heat treatment, vinylon fiber is acetalized.
If acetalization is to be carried out, the amount of acetalization should be less than 10%, but it should be washed with water, treated with oil, and dried. In this drying process, in the uninvented
・Stretch it with a stretched string to prevent shrinkage, then cut it, use a bar if necessary, and crimp it with hot water.

Thus, J. (without acetalizing Motoichi)
By maintaining tension during the drying stage, the number of molecules that shrink upon contact with water is 800-1700, usually 1000-1.
300 fibers are obtained. To make this into a non-woven fabric, the bonded fiber (melt-ponding) method is suitably used.
A needle punch method can also be used if necessary.

That is, the original fiber obtained as described in -1- is passed through a defibration machine to shorten the fiber length, stored in the stonk bins of each series (if a multi-layer structure is used), and then run through a carding machine. After that, they are conveyed by a conveyor while being laminated, and in the case of the melt pounding method, they are passed through, for example, a band dryer, and in the case of the needle punching method, they are needle pounded and then wound up.

Note that other methods are not preferred because the fibers according to the present invention have shrinkage properties due to wood.

1- The fineness of the nonwoven fabric is 0.5 to 7, particularly 1.5 to 5.
, - length is desirable, and the length is preferably 30 to 100 mm, particularly 30 to 7 Q mm.

The nonwoven fabric according to the present invention may be made entirely of PvA as its material, but it is difficult to use an easy adhesive separation method to make the nonwoven fabric, and due to the cost, thermal adhesiveness is not sufficient. It is preferable to use a composite edge M1 (hereinafter also referred to as CON) made of fiber (for example, olefin type, nylon type, or ester type). This CON includes polypropylene products such as Daiwapo NBF J, (Daiwabo), and Chisso ESJ.

So),! Stell type "Melty" (Unitika), nylon type "Heterophil J (I'CI), etc. can be suitably used. Among these, polyp type is most suitable.

Mixing ratio r=PVA/CON is 1.2 to 9, special L: 1
．． 8~5°6 is preferable. If the mixing ratio r is small, the desired shrinkage cannot be obtained, and if it is large, the price will be high.
Difficulties arise when making non-woven fabrics. If the blending ratio of COH is low, only the needle punch method can be used to create a nonwoven fabric, and this method cannot reduce the nonwoven fabric 1 (i to jl) to 70 to 80 g/rn' or less, resulting in high costs. invite.

When making a non-woven fabric when using this combination, each fiber must be
After fibrillating 6, the two may be mixed, or mixed together while being defibrated, to form a web.

[Example] (Example 1) r = PVA/C0N (X/%), m + 11, am The flow direction was changed to obtain test pieces of 30 mm width x 150 mm length, and water shrinkage was examined. Results first
Shown in the table.

Table 1 Here, the time until the start of shrinkage refers to the time taken to soak the test piece in water.
After absorbing water with kitchen paper until a certain moisture content was reached, the time until shrinkage started was measured.

Further, CD in the fiber flow direction refers to a state where the fibers are oriented in the direction perpendicular to the length direction of test No. 1 as shown in FIG. 5, and MO refers to a state where the fibers are oriented in the same direction. moreover,
For defects No. 8, non-woven fabrics were made by the needle punching method (therefore, the basis weight was increased), but for the others, the melt pounding method was used.

According to the results in Table 1, there is almost no difference in shrinkage depending on the fiber direction, and although there is some difference depending on the amount of date, it is PVA/GON that has a large effect on shrinkage.
This is the J-to-ratio of In addition, defects 1 and 2 are unsuitable in terms of contractility. And the ratio of Pv^IC0N is 55
It has been found that it is desirable to make the ratio larger than /45 in order to obtain the desired shrinkage.

(Example 2) The strength ratio due to the difference in fiber direction between MO and CD was examined at t4.

The test piece dimensions were the same as in Example 1, and the contracted length under no load and under a 150 g horizontal (along the length of the test piece) load were investigated. The results are shown in Table 2.

Table 2: Considering the intensity ratio of MO and CD for this result, A
/B=f! , 2:l, and it turns out that the contractile force is stronger in the MO force direction. However, as shown in FIG. 5, since the raw material of the nonwoven fabric is in the CD direction, it has to be in the CD direction for ease of installation on an actual machine.

Therefore, one disposable diaper r r is added only on the ventral side of Fig.
I attached a contraction J) of 80mm thread x 300mm#e to the gold mine of "AY H-Kieseste" (manufactured by Jinshi Paper Co., Ltd.) and checked the shrinkage length.
About 30 mm of shrinkage was observed in the D direction piece. In addition, the material is pv
^/C0N=80/20, 11i・l-36g/m'
(7) It is a thing. As a result, it was found that if the imaginary contraction length of 30 m could be achieved, it would be practical to extend the distance in the CD direction to 1-°.

(Example 3) Shrinkage J4' (61 on the ventral side only) on the actual paper diaper
20 adults (10 men, 10 women) were asked to wear this, and the amount of pressure it exerted on the human body was investigated.

1] To simulate urine, water was forcibly soaked from the front edge of the disposable diaper along the inner surface of the diaper after wearing. In addition, the ti fiber flow of contraction J1 is in the CD direction, and 14-171 is 38 g/m' (However, M, 18 is 80 g/m'
g/rn'). In addition, although the evaluation was average, there was no significant difference between each person. The evaluation method is: No contraction feeling = XX, Slight contraction feeling: Δ, Moderate contraction feeling: O1
Slight pressure: 20, pressure: Severe: × In addition, in the state shown in Figure 3, 30 mm tl'l is placed only on the ventral side.
Sensitivity experiments were also carried out using two small shrinkage pieces with a length of 15 osm. The results are shown in the table below.

From the results, the PVA/CON% ratio is 55/45
It became clear that -90/10 was more favorable.

Also, for positive, 18, lomml'lJX
When we conducted a wearing sensitivity test using a shortened version of +l-+ with a length of 300 mm, 18 people judged it to be a moderate feeling of contraction, and 2 people felt a slight feeling of pressure. It gave the impression that there was a linear restraint, indicating that there was a sense of resistance.

[Effects of the invention] 21. As described above, according to the present invention, it is possible to obtain a paper diaper that has excellent feel, packaging properties, and appearance, is easy to wear, and can reliably prevent I7 from leaking from the front to the rear.

[Brief explanation of the drawing]

Figure 1 shows a water-permeable saw that shows an example of an uninvented disposable diaper structure.
When looking at the side of the contact surface with the human body where a part of the
1 and 2 are cutaway views along the line 1111, FIGS. 3 and 4 are other arrangement states of shrinkage) 1, and FIG. 1...Water-impermeable sheet 2...Water-permeable sheet 3--Absorber 6.6A to 6G/φ Shrinkage length Patent applicant Daio Paper Co., Ltd. Agent J "Riju Yoshihisa Nagai Figure 1 Figure 2

Claims (1)

[Claims] (1) In a paper diaper in which an absorbent body is covered with a water-permeable sheet and a water-impermeable sheet, a belt-shaped polyvinyl material that shrinks on contact with water is formed along the waist circumference direction at least in part of the waist circumference. A front and back leak-proof +I-paper diaper characterized by having a shrinkable piece mainly made of alcohol-based dry nonwoven fabric.