JPS6361402B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disposable diaper that does not require a separate cover.

Conventional disposable diapers of this type generally use polyethylene film as the water-impermeable backing sheet, and although this has a completely waterproof effect, it is not breathable, so the inside of the diaper gets stuffy while being worn. This is also a cause of skin diseases such as so-called diaper rash. In addition, disposable diapers with stretchable elastic members attached to both ends of the crotch area are in practical use;
Although the diaper has relatively good fit around the wearer's legs, the fit is still not satisfactory. In addition, conventional disposable diapers have poor fitability around the waist because elastic members are not attached to the waist because of manufacturing difficulties and high manufacturing costs. Furthermore, since the polyethylene film used as the back sheet has poor elasticity, the diaper as a whole has poor fit to the wearer's body and poor ability to follow the movements of the wearer's body. Therefore, there is a drawback that the wearing condition becomes loose due to body movements, and as a result, excrement leaks from around the legs and waist. Therefore, conventional disposable diapers
Although it has the advantage of being inexpensive and does not require washing, it can be said that it is inferior to diapers that are used in combination with diapers and expensive covers in terms of the performance required for diapers.

An object of the present invention is to provide a disposable diaper that can eliminate the conventional disadvantages as described above, and to achieve that object, the gist of the present invention is to provide at least a water-impermeable diaper. A disposable diaper comprising a back sheet, a water-permeable top sheet, and an absorbent body interposed therebetween, wherein the back sheet has a group of fibers that reach from the top surface of the soft polyurethane foam sheet through the inside to the bottom surface. By being made of a fiber-embedded foam sheet having elasticity and breathability, and by using hydrophobic fibers as at least the fiber group,
The diaper has a water pressure resistance value of 3 cm or more as measured by the JIS-L-1004 (A) water pressure method.

Further, embodiments of the present invention will be described below based on illustrated examples.

FIG. 1 shows an embodiment of a disposable diaper 13 consisting of a front side 10, a back side 11 and a crotch area 12. The diaper 13 includes a water-impermeable back sheet 14, a water-permeable top sheet 15, an absorbent body 16 interposed between these, flap parts on both sides of the absorbent body, and a flap part in the longitudinal direction of the flap part. The elastic member 18 is provided with means 20 for connecting the elastic member 18 and both ends 19a of the back side part 11 around the waist to both ends 19b of the front side part 10.

A fiber-embedded foam sheet is used as the back sheet 14, and this is preferably a flexible polyurethane foam having a thickness of 5 mm or less in which fibers are integrally embedded using a high-speed liquid jet treatment method. The fiber-embedded foam sheet is indicated by reference numeral 14a in FIG.
Fiber groups 14c of 100 mm or less are uniformly distributed without using an adhesive, and are planted from the upper surface through the inside to the lower surface. Therefore, the foam sheet 14b does not lose its inherent elasticity, and the fiber group 14 planted therein is not impaired.
The fiber group 14c does not easily come off from the sheet, and the fiber group 14c connects the upper and lower surfaces of the sheet.
penetrates the air bubbles (cells) of the sheet to form air passages. Furthermore, as is clear to those skilled in the art, normally,
Since flexible foams, especially polyurethane foams, are open cells, the sheet 14 made of them is
b, even though the fiber group 14c does not necessarily penetrate the air bubbles as described above, it has a certain degree of air permeability by itself; , the air permeability of the sheet is improved. Such fiber-embedded foam sheet 1
4a can be easily manufactured by the method for manufacturing a fiber-embedded foam sheet proposed by the present applicant in Japanese Patent Laid-Open No. 11243/1983. The type of fibers in this fiber group 14c is not particularly limited, but hydrophobic fibers are required in order to impart a waterproof effect to the back sheet 14. Furthermore, in order to impart a further waterproof effect to the back sheet 14, it is preferable that the fiber-embedded foam sheet 14a be treated with a water repellent agent. Examples of water repellents include silicone-based, fluorine-based, paraffin-based waxes, amide-based waxes, metal soaps, dimethylpolysiloxane, hydrogen polysiloxane, and epoxy-modified polysiloxane, which are commonly used for water-repellent treatment of fibers. , amino-modified polysiloxane, etc., but are not limited to these materials. The waterproofness of the back sheet 14 is required to have a water pressure resistance value of 3 cm or more as measured by the JIS-L-1004 (A) water pressure method. In addition, when the fibers of the fiber-embedded foam sheet 14a are hydrophobic, a water pressure resistance value of at least 3 cm can be obtained. Here, the term "hydrophobic fiber" includes not only fibers that are inherently hydrophobic, but also fibers that are originally hydrophilic and have been treated to be water repellent.

As the top sheet 15, nonwoven fabric, thin paper, etc. are used. This non-woven fabric can be produced using dry, wet,
Products manufactured by sponbond and high-speed liquid jet processing methods are used, but preferably, the present applicant has published Japanese Patent Application Laid-Open No. 55-71853 and Japanese Patent Application No. 55-114151.
The nonwoven fabric is obtained by the nonwoven fabric manufacturing method proposed in the above issue, and the nonwoven fabric has a good texture because the fibers are entangled by high-speed liquid jetting treatment without using a fiber binder. be.

2 to 8 show embodiments of the diaper 13 having various structures. That is, the diaper 13 shown in FIG. 2 has a stretchable elastic member 18 between a back sheet 14 and a top sheet 15, and a defibrated pulp and absorbent material conventionally generally used as an absorbent material for disposable diapers. The absorbent body 16 is made of large paper or the like. The diaper 13 shown in FIG. 3 includes an absorbent body 16, a stretchable elastic member 18, and a breathable waterproof sheet 22 located on the lower surface of the absorbent body, between a back sheet 14 and a top sheet 15. It is equipped with The diaper 13 shown in FIG. 4 includes an absorbent core 16, a stretchable elastic member 18, and a waterproof sheet 2 disposed sequentially on the lower surface of the absorbent core between a backsheet 14 and a topsheet 15.
2 and a super absorbent polymer 23. The diaper 13 shown in FIG.
4 and the top sheet 15, an absorbent body 16, an elastic member 18, a super absorbent polymer 23 and a waterproof sheet 22 are provided, which are positioned in this order on the lower surface of the absorbent body. The diaper 13 shown in FIG. 6 includes an absorbent core 16, an elastic member 18, and a lower surface and both sides of the absorbent core positioned between a backsheet 14 and a topsheet 15. A waterproof sheet 22 is provided. The diaper 13 shown in FIG. 7 includes an absorbent body 16, a stretchable elastic member 18, and a superabsorbent polymer disposed sequentially on the lower surface of the absorbent body between a back sheet 14 and a top sheet 15. 23 and a waterproof sheet 22, and a portion of the waterproof sheet is positioned on both sides of the absorbent body. The diaper 13 shown in FIG. 8 includes an absorbent body 16 and an elastic member 18 between a back sheet 14 and a top sheet 15.
, a waterproof sheet 22 and a superabsorbent polymer 23 which are sequentially positioned on the lower surface of the absorbent body, and a portion of the waterproof sheet is positioned on both sides of the absorbent body.

As the waterproof sheet 22, the fiber-embedded foam sheet 14a, nonwoven fabric, thin paper, a net-like material made of a hydrophobic material, or a perforated film is used, and the waterproofness of these sheets is JIS-L-1004(A). It is preferable that the water pressure resistance value measured by the water pressure method is 3 cm or more. When the waterproof sheet 22 is the fiber-embedded foam sheet 14a, nonwoven fabric, or thin paper,
To impart effective waterproof properties to these, hydrophobic fibers are used or treated with a water repellent, as in the case of the back sheet 14. When the waterproof sheet 22 is the above-mentioned net-like material or perforated film, it is preferable that the lattice or hole diameter is 0.5 mm or less in order to impart effective waterproof properties to this.

As the super absorbent polymer 23, partially crosslinked starch-modified polymers (monomers and copolymers of graft copolymers with starch such as acrylonitrile, acrylamide, acrylic acid ester, methacrylonitrile, methacrylonitrilic acid ester, vinyl acetate, etc.) are used. ) A sheet in which powder of modified polyvinyl alcohol (epichlorohydrin, isocyanate, acrylic acid, formadehyde, glyoxal, etc. as a crosslinking agent) is sandwiched onto thin paper, a sheet of crosslinked carboxymethyl cellulose, etc. are used, but are not limited to these. .

Such a back sheet 14, a top sheet 15,
These and the absorbent body 16 are partially or fully joined by means such as adhesive or welding to form the diaper 13, but the waterproofness of the diaper 13 as a whole is as follows:
The water pressure resistance value measured by JIS-L-1004(A) hydraulic method is 5 cm or more, preferably 10 cm or more, and most preferably 20 cm or more.

As the stretchable elastic member 18, a tape, a rubber tape, or a string made of a soft foam such as polyurethane foam is used, and the fixation to the diaper 13 is performed by attaching the top sheet in the state in which it is stretched in the longitudinal direction in the flap portions 17 on both sides. 15 and/or the inner surface of the back sheet 14 by adhering it partially or completely to the inner surface of the back sheet 14 using an adhesive, welding, or the like.

As the coupling means 20, a pressure-sensitive adhesive tape, a so-called tape fastener in which a group of engaging protrusions is implanted, a hook, etc. are used, and the attachment parts are not only the waist circumference 19a on the back side 11 but also the front side. It may be located at both ends 19b around the waist of the section 10, or at other appropriate locations.

In the illustrated example, both sides of the crotch area 12 of the back sheet 14 and the top sheet 15 are recessed, but such recesses may not be provided, and the absorbent body 16 may be rectangular. However, the inseam area 12
It may have a so-called hourglass shape with a concave part.

Since the diaper of the present invention having the above-mentioned structure has a back sheet made of a fiber-embedded foam sheet with elasticity, it not only looks and feels good on the skin, but also fits around the body parts to be worn, including around the legs and waist. It has a good overall fit and follows the wearer's body movements, making it easy to wear, and even if the wearer moves freely, the fit will loosen and excrete from around the legs or waist. Things never leak.
In addition, the fibers of the foam sheet reach the back surface from the top surface of the sheet through the inside, penetrate through the air bubbles of the sheet, and form air passages, so the back sheet has good air permeability, and the inside of the diaper is There is little chance of stuffiness occurring.

Thus, the diaper of the present invention has excellent features that cannot be obtained from conventional disposable diapers, and
It is comparable to a diaper that is used in combination with a separate expensive cover, and is extremely useful for practical use.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway developed plan view of the diaper of the present invention, Figs. 2 to 8 are cross-sectional views of structural examples of the diaper of the present invention, and Fig. 9 shows both ends of the waist circumference of the diaper of the present invention joined together. FIG. 10 is an enlarged sectional view of the fiber-embedded foam sheet as the back sheet of the diaper of the present invention. 13...Diaper, 14...Back sheet, 15...
... Top sheet, 16 ... Absorber, 17 ... Flap part, 18 ... Stretchable elastic member, 22 ... Waterproof sheet, 23 ... Super absorbent polymer.

Claims (1)

[Claims] 1. In a disposable diaper consisting of at least a water-impermeable back sheet, a water-permeable top sheet, and an absorbent body interposed between these, the back sheet has a polyurethane fiber group that extends from the top surface of the soft foam sheet to the inside. The sheet is made of a fiber-embedded foam sheet with elasticity and breathability that reaches the lower surface through the fibers, and at least hydrophobic fibers are used as the fiber group, thereby complying with JIS-L-1004(A).
The diaper described above has a water pressure resistance value of 3 cm or more as measured by a water pressure method.