JP2794073B2 - Disposable diapers - Google Patents

Description

The present invention relates to a disposable diaper for babies and adults, and more particularly to a disposable diaper which is decomposed by microorganisms in soil after use.

[Problems to be solved by conventional technology and invention]

2. Description of the Related Art Conventionally, disposable diapers for babies and adults have been replaced with disposable diapers in place of washing, which is unnecessary, hygienic, and easy to handle.

Various types of disposable diapers can be seen, but basically a liquid-permeable sheet (hereinafter referred to as a top sheet) is provided on the surface in contact with the skin, a liquid absorber is provided on the intermediate layer, and a liquid-impermeable material is provided on the back surface. It consists of a sheet (hereinafter, referred to as a back sheet), and urine is quickly absorbed by the liquid absorber from the top sheet, and the back sheet has a structure to prevent urine from leaking to the outside.

For example, JP-B-63-14081 and JP-B-63-64523
As disclosed in Japanese Unexamined Patent Publication, the top sheet is made of non-woven fabric or paper in which composite fibers such as polyester, polypropylene, polyolefin, and rayon are bonded with a binder such as a thermoplastic resin. Pulp, absorbent material such as super absorbent polymer,
It is made of a waterproof plastic, for example, a polyethylene film.

The above-mentioned commercially available disposable diapers are generally handled as waste after use.However, since the materials contain the above-mentioned petroleum-based synthetic high-molecular substances, when they are disposed of by landfill, they do not decompose in the soil, thus causing soil contamination. In the case of incineration at public incinerators as burnable garbage, as the amount of disposable diapers used increases, similar to the incineration of waste plastic, damage to incinerators and harmful components in exhaust gas are social issues. Municipalities are struggling with disposal methods.

[Means for solving the problem]

In view of the above drawbacks, the present invention has a top sheet having sufficient strength, water absorbency, durability, moldability, and properties that can be decomposed by microorganisms in soil and can be incinerated. The aim is to provide disposable diapers consisting of body and backsheet.

That is, the present invention provides, as an intermediate layer, a nonwoven fabric obtained by needle-punching a web made of cotton or rayon or a mixed cellulose fiber of 100% thereof, and a cellulose-containing chitosan salt (hereinafter, referred to as a cellulose-chitosan salt) on the upper surface of the nonwoven fabric. The incineration is also possible by integrally attaching a cellulose film and a cellulose-chitosan salt film to the bottom surface of the porous film, and the disadvantage is solved by constituting a disposable diaper which is decomposed by microorganisms in soil.

[Effect] Normally, it is possible to form a film by subjecting a salt solution of chitosan to flow dry casting, but since this film contains chitosan salt, it is dissolved in water unless fixed with alkali. Also, fine pulp can be formed into a film, but is dissolved in water.

Therefore, the top sheet layer (porous cellulose-
The cellulose-chitosan salt film used for the chitosan salt film) and the backsheet layer (cellulose-chitosan salt film) is present in the fine pulp with the amide group of the chitosan salt in order to increase the shape retention and water resistance in a wet state. By reacting a hydroxyl group, a carbonyl group, and a carboxyl group, the alkali fixing treatment can be omitted.

Furthermore, the film of the topsheet layer and the backsheet layer composed of cellulose and chitosan has a remarkably hard texture, and is degradable by using glycerin or starch as a plasticizer in a mixing ratio that does not impair the water resistance. The texture can be softened without any trouble.

The cellulose-chitosan salt porous film, which is the top sheet layer in contact with the skin, quickly absorbs urine from the voids and transports it to the liquid absorber, so that the skin surface is always smooth and does not cause discomfort.

In addition, since the liquid absorber in the configuration of the present invention is a bulky needle-punched nonwoven fabric made of water-absorbing fibers such as cellulosic cotton, hemp, rayon, etc., urine transported from the top sheet can be promptly performed. Absorb and retain water.

Since the back sheet layer is composed of a liquid-impermeable cellulose-chitosan salt film, it is possible to almost completely prevent leakage of urine to the outside.

In addition, since the disposable diaper is made of naturally occurring cellulose, chitosan, or the like, it does not generate high heat or harmful substances even when burned in an incinerator, and is completely decomposed by microorganisms in the soil without soil contamination.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[Example 1] Fig. 1 is a schematic sectional view of the structure of a disposable diaper according to the present invention, and a liquid absorber (A) constituting an intermediate layer as shown in the drawing.
Is 2d × 51mm of rayon fiber (1) which is generally marketed
Is used as a cellulosic fiber, using a known card and a web forming machine such as a cross wrapper or a land weber, for example, a cross web having a basis weight of 200 g / m ² is formed,
It is formed by performing a needle punching treatment (2) of 50 P / cm ^{2 by} a needle punching machine.

As shown in FIGS. 2 and 3, the back sheet layer (B) disposed on the lower surface of the intermediate layer is a fine cellulose fiber (3) having a diameter of 1 μm or less (MFC-100 manufactured by Daicel Chemical).
And chitosan (Kyowa Yushi Flownac N): acetic acid = 1:
0.5 (weight ratio) chitosan salt (4) aqueous solution (concentration 1%)
Was adjusted to be 80:20 (weight ratio) cellulose-chitosan salt aqueous solution (concentration: 1%), and then formed by flow dry casting (drying condition: 100 ° C. × 5 min), for example, cellulose with a basis weight of 20 g / m ² . -Chitosan salt film (5).

In addition, the top sheet layer (C) disposed on the upper surface of the intermediate layer was prepared by adding cellulose:
Chitosan salt: polyethylene glycol = 60:20:20 (weight ratio), an aqueous solution (concentration 1%) to which polyerylene glycol is added is subjected to flow dry casting treatment, and the film obtained is washed with water to remove polyethylene glycol. A disposable diaper was formed by forming a cellulose-chitosan salt porous film (7) having, for example, a basis weight of 25 g / m ² having a large number of micropores (6) obtained as described above.

[Example 2] The liquid absorber (A) constituting the intermediate layer was formed in the same manner as in Example 1, and the top sheet layer (C) disposed on the upper surface of the intermediate layer was adjusted in the same manner as in Example 1. In the liquid, cellulose: chitosan salt: glycerin = 60: 20: 20 (weight ratio)
A 1% concentration aqueous solution containing glycerin was treated in the same manner as in Example 1 to form a cellulose-chitosan salt porous film (7) having a basis weight of 20 g / m ^{2 on} the surface, and disposed on the lower surface of the intermediate layer. For the back sheet layer (B), a 1% aqueous solution in which glycerin was added to the adjustment liquid used in Example 1 so that cellulose: chitosan salt: glycerin: polyethylene glycol = 50: 20: 10: 20 (weight ratio) was added. The same treatment as in Example 1 was performed to form a cellulose-chitosan salt film (5) with a basis weight of 25 g / m ² .

(Comparative example)

For comparison with the disposable diaper of the present invention, the liquid absorber as the intermediate layer is formed using the same fiber and basis weight cross web as in the example, and the top sheet layer disposed on the upper surface of the intermediate layer is a known spunbond nonwoven fabric. 25g / weight per unit manufactured by manufacturing equipment
The polyester bread bonded nonwoven fabric of m ² is disposed, the back sheet layer is disposed polyethylene film having a basis weight of 20 g / m ² was formed by a known plastic film production apparatus, a sample of Comparative Example a disposable diaper constructed by bonding together .

The mother actually used the disposable diapers obtained in each of the Examples and Comparative Examples for infants, and the used diapers were buried in the soil (5 cm below the ground), and the degree of decomposition after three months was observed. The results are shown in the following table.

[Effects of the Invention] As described above, the present invention absorbs a film and a porous film made of chitosan-cellulose as a backsheet layer and a topsheet layer of a disposable diaper, and absorbs a needle-punched nonwoven fabric made of a cellulose-based natural fiber. When used as a body, urine of infants is quickly absorbed from the top sheet layer into the liquid absorber, and the back sheet layer completely prevents leakage of urine to the outside.

Further, since the disposable diaper is made of a natural material as described above, it is gentle on the skin of infants, and has no rough skin or rash. In addition, since it is decomposed by microorganisms in the soil, it can be disposed of by landfill or incineration without any problems, and has excellent workability and has an effect of eliminating pollution problems.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a disposable diaper showing an embodiment of the present invention, FIG. 2 is a structural view before a reaction between a cellulose fiber and a chitosan salt, and FIG. 3 is a structure showing a state after the reaction. FIG. (1) Rayon fiber (2) Needle punching fiber shape (3) Fine cellulose fiber (4) Chitosan salt (5) Cellulose / chitosan salt film (6) Fine pore (7) ... cellulose / chitosan porous film

──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazunori Yoshihara 2-3-3 Hananomiyacho, Takamatsu City, Kagawa Prefecture Inside the Shikoku Industrial Technology Laboratory (72) Inventor Mutsuo Nakagawa 1 Mefu, Takarazuka-shi, Hyogo Chome 21-15 (72) Inventor Yasuo Nakagawa 1-7-7 Kotobukicho, Takarazuka-shi, Hyogo (72) Inventor Masaaki Nishida 1-31-2 Higashi-Namba-cho, Amagasaki-shi, Hyogo Examiner Masato Matsuwana Field (Int.Cl. ⁶ , DB name) A61F 13/15

Claims (6)

(57) [Claims] 1. A needle-punched nonwoven fabric composed of a cellulose-based natural fiber or a cellulose-based semi-synthetic fiber or a mixed fiber of both, as an intermediate layer, and a cellulose-containing chitosan salt porous as a topsheet layer on the upper surface of the nonwoven fabric. A disposable diaper having a film disposed thereon, a cellulose-containing chitosan salt film disposed as a back sheet layer on a lower surface, and integrally bonded. 2. The disposable diaper according to claim 1, wherein the cellulosic natural fiber and the cellulosic semi-synthetic fiber are cotton, polynosic rayon, cupra rayon, irregular shaped rayon, and porous rayon. 3. The disposable diaper according to claim 1, wherein the cellulose contained in the chitosan salt film and the porous chitosan salt film is a fine pulp having a diameter of 1 μm or less. 4. A disposable diaper comprising a cellulose-containing chitosan salt film and a porous cellulose-containing chitosan salt film containing glycerin or starch as a plasticizer. 5. The disposable diaper according to claim 1, wherein the cellulose-containing chitosan salt film is obtained by subjecting a cellulose-containing chitosan acidic solution to flow dry casting treatment. 6. A porous cellulose-containing chitosan salt film is formed by washing an acid solution containing cellulose-containing chitosan and polyethylene glycol with a flow-dry cast film with water to remove the polyethylene glycol. The disposable diaper according to claim 1, characterized in that: