JP2579365B2 - Disposable diapers - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disposable diaper, and more particularly to a pants-type disposable diaper having waterproofness as well as flexibility and breathability.

[Prior art] Usually, pants-type disposable diapers include those that are three-dimensionally formed in a pants-like shape from the beginning and those that are configured in a planar shape, and those that become pants-like when worn. In any case, the entire pants are basically constituted by a three-layer structure composed of a water-permeable top sheet, an absorbent, and a waterproof or paper-backed sheet made of polyethylene or polyethylene film. However, in the pants-type diaper having this structure, not only the crotch but also the entire waist of the abdomen and back are hermetically sealed with waterproof paper or waterproof cloth. For this reason, the air permeability is extremely poor, and causes unevenness and rash on the skin. Mothers' needs for breathable diapers are high. Disposable diapers having a water-permeable film provided with fine holes or small holes to improve air permeability have also appeared.

Although these films are breathable under pressure, they are far from natural ventilation and still do not provide diapers with sufficient and sufficient breathability.

Further, the diaper using the waterproof paper or the waterproof film is so hard that it makes a rough sound, it is hard to feel rough and soft, lacks a soft tactile sensation, and gives a cold touch, so that it is uncomfortable to wear.

[Problems to be solved by the invention]

It is an object of the present invention to solve these drawbacks and to provide a disposable diaper having appropriate strength, air permeability, waterproofness, and bleeding and leakproofing.

[Means for solving the problem]

The disposable diaper according to the present invention is a disposable diaper in which a top sheet, an absorbent layer and a back sheet are laminated, wherein the top sheet has urine permeability at least in an area where the absorbent layer is provided, and the periphery thereof is repellent. Along with being a water-based nonwoven fabric, the backsheet is entirely made of a water-repellent nonwoven fabric, and is provided with a waterproof reinforcing film layer only at a portion where a body pressure is applied, and only at a central portion where urine absorption is large. Disposable diapers.

The disposable diaper of the present invention is characterized in that the waterproof reinforcing film layer is adhered to the surface of the absorbent layer on the back sheet side, and furthermore, in order to prevent the leakage of urine more sufficiently, the urine permeation provided on at least the top sheet is provided. A waterproof reinforcing film layer is provided in a wider range than the range of the active region and the absorption layer. Further, it is preferable that the nonwoven fabric is made of polyolefin fibers.

Hereinafter, the disposable diaper of the present invention will be described in more detail with reference to the accompanying drawings showing one embodiment of the present invention.

In FIG. 1, a disposable diaper (hereinafter, referred to as a diaper) 1 according to the present invention has a back sheet 2, a water-absorbing layer 6 provided in a band shape on the center thereof, and urine permeability at least in a range of an absorbent layer, and Is a water-repellent top sheet 7,
Further, it is composed of a waterproof reinforcing film 8.

The backsheet 2 is formed substantially entirely of at least one thin nonwoven fabric. The nonwoven fabric is not particularly limited as long as it has water repellency, but a waterproof nonwoven fabric is preferable from the viewpoint of preventing oozing of absorbed urine. For example, it is formed by forming continuous filament fibers melt-spun by a spunbond method into a web and joining the webs. For joining the web, a method such as joining with an adhesive, joining with a low melting point fiber or a composite fiber, dispersing a binder during the formation of the web and melting and joining, or interlacing fibers with a needle punch, a water stream, or the like. Is also possible,
In order to further increase the strength and flexibility of the sheet, it is preferable to form the sheet by partial thermocompression bonding. Partial thermocompression bonding can be performed by an ultrasonic method or through a web between heated embossing rolls, whereby, for example, floating and sinking patterns such as pinpoints and rectangles are scattered over the entire surface of the sheet.

The nonwoven sheet made by spunbonding has excellent air permeability due to its long fiber length, has practical strength, and, unlike the wet or dry method, turns the fiber into a sheet without oil treatment or the like. The properties such as water repellency unique to the fiber are utilized.

Short fiber webs formed by so-called carding, papermaking, and the like are similarly bonded and used, but in this case, a water-repellent or water-repellent material provided with a water-repellent agent or a waterproofing agent is more preferable.

As the fibers used for the nonwoven sheet, polypropylene, polyolefin fibers such as polyethylene, polyethylene terephthalate fibers, polyamide fibers, etc. are hydrophobic,
It is suitable from the viewpoint of strength or flexibility.

Polyolefin fibers are particularly preferred from the viewpoint of hydrophobicity. If necessary, mixing with these conjugate fibers, mixed fibers, and cellulosic fibers or other fibers having a special function is also effective.

The thickness of the fiber is preferably from 0.1 to 5 denier, and particularly preferably from 0.1 to 3 denier from the viewpoint of softening and covering properties.

The basis weight of the non-woven sheet depends on the fiber used, but is about 5
~50g / m ² is preferred. The thickness of the nonwoven fabric obtained with this basis weight is about 0.1 to 0.5 mm.

Regarding the prevention of water leakage of the backsheet 2 formed of such a nonwoven fabric, in particular, in the case of a backsheet made of a polyolefin-based fiber by a spunbond method, the water repellency peculiar to the fiber is exhibited without the application of spinning and card oil, and the basis weight ( The adjustment of g / m ² ) sufficiently prevents water leakage, so that it is not necessary to dare to waterproof. However, the back sheet made of nylon fibers, ester fibers, or the like may be subjected to a water repellent treatment in order to increase the water repellency. The water repellent treatment may be performed by a dipping method, but can be performed by melt coating, solvent coating, emulsion coating, or the like. A melt coating or a solvent coating is preferable to an emulsion coating containing an activator or the like which easily disperses the water repellency. To make the most of the soft hand of the nonwoven sheet, it is also effective to leave single-sided fibers by single-sided coating. Further, in the short fiber nonwoven fabric such as a card web, it is usual that various oils of the fiber are applied in the process, and it is preferable to select a water-repellent oil at this time. What is necessary is just to perform a water-repellent and waterproof treatment.

As the water repellent, a silicone-based or fluorine-based processing agent may be used, but petroleum-based natural wax is preferred from the viewpoint of cost and performance, and paraffin-polyethylene blending from the viewpoint of imparting flexibility to the sheet. Is particularly preferred. There is no particular limitation on the amount of the water repellent used, and the amount can be appropriately adjusted within a waterproof range.

By using such a non-woven fabric, it has much more air permeability than conventional diapers using a waterproof film, etc., and does not cause stuffiness, rash, etc. , Rattling and the like are also reduced.

However, although it has some waterproofing effect as it is, there is a possibility that water is leaked such as when urine is absorbed in a part or body pressure is concentrated in the part where the urine is absorbed in relation to the capacity of the absorbing layer. For this reason, as a method of reinforcing waterproofness while making use of air permeability, by providing the waterproof reinforcing film 8 on the back sheet or between the back sheets of the absorbent layer, the diaper has sufficient air permeability as a whole. Not only that, a diaper that does not leak under special conditions can be obtained.

As the waterproof reinforcing film 7, a polyolefin-based film such as polyethylene and polypropylene, a polyolefin copolymer-based film such as EVA, a polyamide-based film, and a polyester-based film can be used as much as possible. Is useful as a flexible and inexpensive film. In addition, these may be a film alone, a film laminated with a tissue, a nonwoven fabric, or the like, and a material subjected to a flexible treatment such as creping in order to eliminate a sense of discomfort.

The size of the waterproof reinforcing film should be the same as the size of the absorbent layer, or the one shown in Fig. 1 where the central part of the diaper where urine concentrates is reinforced, and the part where body pressure easily concentrates on the absorber. The reinforced one shown in FIG. 2 is preferable.

Depending on the gender difference, the absorption site, the manner in which pressure is applied at the time of urination, and thereafter in the body position change, so it is preferable to set the size to the absorption layer or a slightly wider range.

In addition, fixing of these waterproof reinforcing films is generally performed by bonding to an absorbent layer or a back sheet, and extrusion lamination to a necessary portion of the back sheet,
It is effective to use an adhesive layer or a layer laminated on a tissue of an absorption layer. Careful attention must be paid to the hardening of the hand and the generation of rattle.

Needless to say, it is not preferable to fix the peripheral part as a diaper peripheral part in terms of air permeability.
It is important to use the waterproof reinforcing film as small as possible.

By adhering the waterproof reinforcing film layer to the outside of the back sheet, the entire diaper can be used as a target portion to which an adhesive tape for attaching and fixing the entire diaper in a pants shape is fixed. Naturally, it is more preferable to increase the strength surface and the film thickness and to perform a surface release treatment.

Furthermore, the present inventors have studied the relation between the top sheet and the top sheet as a preferable use form, and found that the hydrophilicity of the urine permeability of the top sheet is transmitted to the absorbent layer depending on the amount of urine that has permeated or is absorbed once. It may spread out due to the bleeding phenomenon or the like out of the range, and when the body pressure is applied, it may be moistened more than the transmission range. On this occasion,
At the end of the absorbent layer, if there is no absorbent layer and there is no waterproof reinforcing film layer, urine oozes through the back sheet in the area where body pressure is applied, so that at least the area outside the absorbent layer and / or waterproof It is more preferable to combine a topsheet having no hydrophilicity other than the range of the reinforcing film layer.

The method for manufacturing the top sheet and the materials used are not particularly limited, but nonwoven fabrics other than the urine-permeable portion and which can easily impart water repellency are preferred. For example, spunbonded nonwoven fabrics and short-fiber nonwoven fabrics by the various bonding methods described above are used.

Since the non-woven sheet by the spun bond method has a long fiber length, it has practical strength, and unlike the case of the wet method or the dry method, the fiber is made into a sheet as it is without oil treatment or the like, By applying a water-permeabilizing agent to a portion requiring urine permeability, the properties around the fiber, such as water repellency, are utilized.

As described above, in nonwoven fabrics made of short fiber webs by the carting method, etc., oils are applied in each step, so it is necessary to make these oils hydrophilic or water-repellent. It can be achieved by imparting the first performance and imparting water repellency at the periphery or urine permeability at the center of the second performance after bonding. As the water permeating agent, surfactants such as alkyl alcohols, alkyl phenols, ethylene oxide adducts of higher fatty acids and other various nonionics, alkyl sulfates, alkyl phosphates, and other various anions are generally used. Mixtures may be used if necessary.

It is preferred that the urine permeable portion be within the range of the absorbent layer. Although the topsheet is effective as shown in FIG. 1 provided in the form of a vertical stripe, it is important in this case to use a waterproof reinforcing film layer in accordance with the urine permeable portion.

In the diaper 1 shown in FIG. 1 as an embodiment, the back sheet 2 and the top sheet 7 are
It is formed in a flat pants-like shape which is generally fan-shaped and spreads in both directions of 4, 4 'and the back 3, 3'. At the center of the back sheet 2, a band-shaped absorbing layer 6 extending from the abdomen 4, 4 'to the back 3, 3' is provided. The width of the absorbing layer 6 is the crotch 5
The waistline 4 of the abdomen 4 and the back 3,3 '
Shorter than 0,30 is preferable from the viewpoint of leakage prevention and wearing comfort. The top sheet 7 is, for example, a short-fiber or long-fiber nonwoven fabric provided with a water-permeable portion 71 shown by hatching in FIGS. 1 and 2 and a water-repellent portion 72 around the portion 71. Needless to say, a water-permeable or water-repellent nonwoven fabric may be bonded to a required portion.

The absorption layer 6 is obtained by covering the absorber 62 with a tissue 61.

The waterproof reinforcing film layer 8 is located on the outside of the back sheet as shown in FIG. 2 or between the absorbent layer 6 and the back sheet 2 as shown in FIG. Provided in any form. It is also important that air flow between the top sheet side and the back sheet side be smooth.

The top sheet 7 and the back sheet 2 and the absorbing layer 6 are partially adhered to each other using a hot melt agent or by a heat sheet method. As the material used for the absorber 62, pulp crush, powdery superabsorbent polymer, or a combination thereof can be used.

As shown in FIG. 1, an adhesive tape is applied to both ends 31, 31 'of the back portion 3 of the back sheet 2 so as to be fastened as pants. In the crotch portion, one to several foams such as urethane and raw rubber, and thread-like elastic bodies 9, 9 'are adhered between the top sheet and the pack sheet so as to fit the legs. .

As shown in FIG. 6, as a part of the top sheet, it is also preferable that the hydrophobic portion or another hydrophobic non-woven fabric is protruded three-dimensionally to wrap the elastic body so as to fit the leg more and to strengthen the leakage prevention. .

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Example 1 A polypropylene web (having a basis weight of 25 g / m ² ) obtained by a spun bond method was passed between heated embossing rolls, and was partially thermocompression-bonded to obtain a nonwoven fabric having a pinpoint dot pattern. The average thickness of the obtained nonwoven fabric was 0.25 mm, and the air permeability with a Frazier-type air permeability tester was 330 cc / cm ² / sec.

As shown in FIGS. 1 and 2, this nonwoven fabric is provided with a nonionic surfactant and a work product with alkylphenol ethylene oxide at 0.5% in the central portion 11 cm wide to form a water-permeable portion 71 and the periphery thereof. Was made a water-repellent portion 72 without any treatment agent, and used as a top sheet.

Next, the polypropylene web (having a basis weight of 30 g / m ² ) obtained by the same spunbonding method was partially thermocompression-bonded to a pinpoint pattern between embossing rolls. The thickness of this nonwoven fabric was 0.30 and the air permeability was 250 cc / cm ² / sec. As shown in FIGS. 1 and 2, the nonwoven fabric has a width of 15 cm and a thickness of 20 cm at the center thereof.
μ polyethylene film was extruded and laminated. This laminade sheet was used as a back sheet with the film side facing out, an absorbent layer 6 having a width of 13 cm was superimposed on the center of the back sheet, and combined with a top sheet, each layer was mutually bonded to a hot melt agent to form a disposable diaper. In addition, the pulp layer containing the superabsorbent polymer was wrapped with a tissue at 500 g / m ² so that the absorption layer became about 5 g / sheet, and this was cut and used.

The manufactured diaper was soft and soft as a whole, and had moderate strength, breathability, and waterproofness.

The performance of the top sheet, a urine leakage test, and a practical test were performed by the following methods.

First of all, the performance of the top sheet was to spread the liquid on the top sheet surface when one drop of saline was dropped on the diaper (permeate part length x width (mm)). Water is absorbed from the center of the top sheet, and a load equivalent to 2.5 kg / 10 cm square body pressure is applied to the absorbing part by 10
Take for a minute. After that, absorb 70 cc more and repeat the same operation a total of 3 times, leaking to the outside of the back sheet at this time,
The degree of wetness was observed. In the practical test, a wearing test was actually performed as a diaper, and the wearing condition and leakage of urine were observed. Table 1 shows the results.

Further, in this embodiment, the fixing adhesive tape at the time of mounting was fixed on the laminate film, and it was possible to use the tape while re-fixing it several times.

Comparative Example 1 A diaper was prepared using the nonwoven fabric of Example 1 in which the top sheet was entirely subjected to water permeation treatment, and a milky white polyethylene film having a thickness of 30 μm as the back sheet. This is a typical disposable diaper of the conventional type. Table 1 shows the results.

Comparative Example 2 A diaper was prepared in the same manner as in Example 1 except that the topsheet was made into a nonwoven fabric subjected to a water-permeability treatment, and the other parts were left as they were. The difference in effect when the partial prevention reinforcing film layer was provided on the back sheet was observed. Table 1 shows the results.

Comparative Example 3 In Example 1, a diaper having a milky white polyethylene film as the back sheet as in Comparative Example 1 was produced.
We decided to grasp the partial permeation effect of the topsheet.
Table 1 shows the results.

Comparative Example 4 In Example 1, a water-repellent nonwoven fabric without a waterproof reinforcing film layer on the backsheet was used. We decided to clarify the effect of the partial waterproof reinforcement film layer. Table 1 shows the results.

Example 2 In Example 1, as a top sheet, a nonwoven fabric (25 g / m ² ) in which a polyethylene-polypropylene conjugate fiber and a card web (3d × 54 mm long) were bonded by hot air at 150 ° C.
Was used. The central part of this non-woven fabric is provided with 0.4% of an anionic water-permeabilizing agent, and the periphery uses a water-repellent oil agent such as silicon oil as a spinning oil agent and carding oil agent for short fiber web production. And has water repellency. Using this top sheet, a disposable diaper was prepared in the same manner as in Example 1. The obtained diaper had softness of cloth feel as a whole, had both air permeability and waterproofness, and did not leak. The evaluation result is
It is shown in the table.

Example 3 Using the same material as in Example 1, FIGS.
A disposable diaper as shown in FIG. 5 was prepared.

The waterproof reinforcing film layer 8 was provided so as to cover the side surface of the absorbing layer together with a tissue 61 wrapping the surface of the absorbing layer 6 with a film thickness of 20 μm. The absorption layer was of a type with a slightly narrowed crotch. As the back sheet, the polypropylene nonwoven fabric (30 g / m ² ) produced by the spun bond method of Example 1 was used without film lamination.

Further, the waist 3 and the abdomen 4 are provided with polypropylene films 10, 10 'having a length of about 3 cm as shown in FIGS.
Is provided between the top sheet and the back sheet to prevent bleeding leakage in the length direction of the diaper. The resulting diaper had a soft feel, excellent breathability, and no bleeding.

Example 4 In Example 1, as shown in FIG. 6, the hydrophobic portions provided at both ends of the top sheet were projected three-dimensionally to enclose the elastic body 9.

Further, a diaper having a form as shown in FIG. 6 was prepared by using a hydrophobic non-woven fabric separately from the three-dimensionally protruding portion and bonding it to the hydrophobic portion of the top sheet shown in FIG. The finished diaper was flexible overall and did not leak or leak.

Example 5 A treatment agent was applied to the top sheet of Example 1 such that the water-permeable portion of the top sheet was reduced in size by about 5 mm to the area of the absorbent layer 6 of the diaper. The hydrophobic portion of the topsheet was formed around the entire diaper of the crotch, back and abdomen, so that there was no leakage of urine.

In the embodiments of the present invention, not only each embodiment but also a combination of these embodiments not only can enhance the effect, but also can make the design effective.

〔The invention's effect〕

The disposable diaper of the present invention has an extremely excellent cloth-like softness and breathability because its back sheet is mainly made of a water-repellent nonwoven fabric, and therefore can prevent rough skin beforehand, and has a conventional full-surface film type. Compared to, there is less cold and less rustling.

Further, the diaper of the present invention has urine permeability in the area of at least the absorbent layer provided as a top sheet, and the periphery thereof uses a water-repellent non-woven fabric and the entire water-repellent non-woven fabric as a back sheet. In order to provide the waterproof reinforcing film layer at least in the area where the body pressure is applied, the central part which absorbs urine a lot, the urine permeable area provided in the top sheet and the area of the absorbent layer, a conventional full-screen film or simply nonwoven fabric and prevention film In addition to preventing the urine from leaking together with the water repellency of the back sheet, it is possible to have a diaper that is completely different from the back sheet that has no air permeability laminated with
By attaching a hydrophilic top sheet, the absorbed urine is prevented from oozing out, and there is an effect of completely preventing oozing leakage at a portion where there is no absorbent layer.

[Brief description of the drawings]

FIGS. 1 and 2 are front views schematically showing a disposable diaper of the present invention, FIGS. 3, 4, and 5 are examples of cross-sectional views of a central portion, and FIG. 6 is FIG. It is a longitudinal cross-sectional view of the central part of FIG. DESCRIPTION OF SYMBOLS 1 ... Pant type diaper, 2 ... Back sheet, 3 ... Back part, 31 ... Adhesive tape for mounting and fixing, 4 ... Abdomen, 5 ...
Crotch, 6 ... absorbing layer, 7 ... top sheet, 71 ... urine permeable part (water permeable part), 72 ... water repellent part (hydrophobic part), 61 ... tissue, 62 ... absorber, 8 ... … Waterproof reinforcement film, 9 ……
Elastic body, 10 ... Anti-bleeding film.

Claims (1)

(57) [Claims] 1. A disposable diaper in which a top sheet, an absorbent layer and a back sheet are laminated, wherein the top sheet has urine permeability at least in a region where the absorbent layer is provided, and its periphery is water repellent. With a certain non-woven fabric,
A disposable diaper, wherein the back sheet is entirely made of a water-repellent nonwoven fabric, and a waterproof reinforcing film layer is provided only at least in a part where body pressure is applied and in a central part where urine is absorbed abundantly.