JP7607276B2 - Absorbent articles - Google Patents

Description

The present invention relates to an absorbent article equipped with a perforated film.

Generally, absorbent articles such as light incontinence pads, pants-type disposable diapers, and tape-fastened disposable diapers are composed of a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body placed between the two sheets. As a result, bodily fluids such as urine are absorbed into the absorbent body through the top sheet, and the back sheet prevents them from leaking to the outside. Various ideas have been incorporated into such absorbent articles to improve the absorbency of bodily fluids, improve the wearing comfort of the wearer, prevent leakage, etc.

For example, there is a technology that improves absorbency performance such as wet back and absorption speed by providing a perforated film at a specified position on an absorbent article. The open area of the perforated film on the skin side and non-skin side is set so that the skin side is larger than the non-skin side, thereby improving wet back and absorption speed.

As an example of an absorbent article using a perforated film, Patent Document 1 discloses a technology in which, in an absorbent article having a liquid-permeable surface material, a liquid-retentive absorbent material, and a liquid-impermeable leak-proof material, the surface material is made of at least a liquid-permeable sheet formed by laminating and integrating a skin-contacting surface layer and a non-skin-contacting surface layer, and the skin-contacting surface layer is formed of a perforated film made of a thermoplastic resin or a nonwoven fabric made of synthetic fibers.

Patent Document 2 discloses a urine pad that includes a surface layer, an absorbent layer, and a bottom layer, which are arranged in this order from top to bottom. The absorbent layer includes, from top to bottom, a perforated film layer, a core layer, and a bottom attachment layer, the perforated film layer being located between the surface layer and the core layer, and the bottom attachment layer being located between the core layer and the bottom layer.

Patent Document 3 discloses an absorbent having an absorbent layer containing at least one of SAP and fluff pulp as an absorbent component, the absorbent having an absorbent covering layer arranged in contact with the absorbent layer and made of a water-resistant, highly breathable synthetic resin perforated film, the absorbent covering layer being configured to prevent the absorbent components from escaping from the absorbent and to maintain shape stability, the perforated film having numerous protrusions with a funnel-shaped structure with small openings at the top and large openings at the bottom, and the tops of the protrusions are arranged to be in contact with the absorbent layer.

Japanese Patent Application Publication No. 8-66425 Utility Model Registration No. 3215515 JP 2002-355271 A

However, in the above-mentioned Patent Document 1 and Patent Document 2, both of which are provided with perforated films, although they are excellent in preventing liquid backflow and absorbing speed, such as in wet bags, they are not effective in diffusing liquid in absorbent articles, and the absorption performance of the absorbent body is not fully demonstrated.

In addition, Patent Document 3 uses a perforated film with a smaller opening area on the skin side than on the conventional non-skin side, and is configured so that the surface with the smaller opening area is in contact with the absorbent body. However, even in this case, there is no technical idea of improving the diffusion of the liquid.

As mentioned in the above literature, some sanitary napkins and disposable diapers use perforated films as the liquid-receiving surface material, and the placement of the perforated film improves liquid permeability and liquid backflow prevention. However, although perforated films are often more expensive than regular nonwoven fabrics, they are insufficient to provide more beneficial liquid permeability and liquid backflow prevention properties, and because they are resin films, they feel hard to the touch.

Therefore, the present invention has been made in consideration of the above problems, and aims to provide an absorbent article that has the characteristic of quickly wetting and spreading when it receives liquid from urination, etc., thereby improving diffusion and liquid permeability and improving prevention of liquid backflow.

Specifically, the objective is to provide an absorbent article that can reduce the hardness of the resin film by disposing a perforated film between the top sheet and the absorbent body, and can also diffuse excreted urine throughout the entire absorbent body, allowing liquid to be widely absorbed throughout the entire absorbent body, thereby improving the ability to prevent liquid backflow.

In view of the above problems, the inventors of the present invention conducted intensive research. As a result, they discovered that the above problems could be solved by providing a perforated film with a specific configuration between the top sheet and the absorbent body, and thus completed the present invention. Specifically, the present invention provides the following:

(1) The first aspect of the present invention is an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet, and a perforated film having a plurality of funnel-shaped openings disposed between the top sheet and the absorbent body, characterized in that the perforated film has openings with a small opening diameter on one side in the thickness direction and a large opening diameter on the other side, and is disposed so that the openings on the side with the large opening diameter face the absorbent body.

(2) A second aspect of the present invention is the absorbent article according to (1), characterized in that the aperture diameter of the perforated film is 2 mm or less, the number of apertures is 50 or more per ^cm2 , and the basis weight is 20 g/m2 or ^more and 60 g/m2 ^or less.

(3) The third aspect of the present invention is an absorbent article according to (1) or (2), characterized in that the difference between the aperture diameter of one surface having a larger aperture diameter and the aperture diameter of the other surface having a smaller aperture diameter is 0.03 mm or more and 0.15 mm or less.

(4) The fourth aspect of the present invention is an absorbent article according to any one of (1) to (3), characterized in that a liquid-dispersible second sheet is disposed between the top sheet and the perforated film.

(5) A fifth aspect of the present invention is an absorbent article according to any one of (1) to (4), characterized in that the second sheet has a basis weight of 10 g/m2 ^or more and 60 g/ ^m2 or less.

Therefore, according to the present invention, by having the smaller pore diameter of the perforated film facing the skin side, in addition to permeation into the absorbent body (downward), the film also has excellent diffusion in the lateral direction (front, back, left and right). As a result, when liquid is absorbed from urination, etc., it quickly wets and spreads, improving diffusion and liquid permeability, and improving prevention of liquid backflow, making it possible to provide an absorbent article.

FIG. 1 is a plan view of an absorbent article of the present invention. 2 is a cross-sectional view taken along line X ₁ -X ₁ in FIG. FIG. 2 is a cross-sectional view of the apertured film of the present invention.

Below, the form for carrying out the present invention (hereinafter, the embodiment) will be described in detail with reference to the attached drawings. However, these are presented for the purpose of illustration and do not limit the present invention. Note that the same elements are given the same reference numerals throughout the description of the embodiment.

In the description of this specification, the absorbent article 1 is worn when it is at least one of the time when it is worn and the time after it is worn. The longitudinal direction of the absorbent article 1 is the direction from the front to the back of the wearer when the absorbent article 1 is worn, and is the direction indicated by the symbol Y in the figure. The width direction of the absorbent article 1 is the direction horizontal to or perpendicular to the longitudinal direction, and is the direction indicated by the symbol X in the figure. Furthermore, the skin contact surface is the surface of each member, such as the absorbent body, that is placed on the skin side of the wearer when worn, and the non-skin contact surface is the surface of each member, such as the absorbent body, that is facing the opposite side to the skin side of the wearer when worn. Body fluids refer to liquids discharged from the body to the outside, such as urine, blood, and water in loose stool. Furthermore, examples of the absorbent article 1 include light incontinence pads, pants-type paper diapers, and tape-fastened paper diapers, regardless of whether they are for babies or adults, but are not limited to these and may be other absorbent articles.

<Absorbent Articles>
Fig. 1 is a plan view of an absorbent article 1 according to an embodiment of the present invention, as viewed from the top sheet 10 side. As shown in Fig. 1, the absorbent article 1 includes a liquid-permeable top sheet 10 arranged on the skin contact side, a liquid-impermeable back sheet 20 arranged on the non-skin contact side facing the top sheet 10, and an absorbent body 30 arranged between the top sheet 10 and the back sheet 20. As a result, the absorbent body 30 is sandwiched between the top sheet 10 and the back sheet 20.

It is preferable that the longitudinal dimension of the absorbent article 1 is 100 mm or more and 800 mm or less, and the width dimension is 50 mm or more and 500 mm or less. By adjusting the dimensions of the absorbent article 1 to be within the above ranges, it is possible to obtain an absorbent article 1 suitable for light incontinence pads, pants-type paper diapers, tape-fastened paper diapers, etc.

As shown in FIG. 2, the absorbent article 1 may have a pair of three-dimensional gathers 60 having elastic members for three-dimensional gathers on the top sheet 10 along the longitudinal direction of the absorbent article 1 in order to prevent side leakage of bodily fluids excreted by the user. The three-dimensional gather sheet is arranged so that the outer end of the three-dimensional gathers 60 in the width direction of the absorbent article 1 is fixed to the back sheet, the inner end is fixed to the top sheet 10, and the center is a free end that is not fixed to the top sheet 10. By providing the elastic members for three-dimensional gathers along the longitudinal direction, the three-dimensional gathers 60 have a standing property and can be deformed to fit the body shape of the wearer. For example, polyurethane thread, a belt-shaped polyurethane film, thread-shaped or belt-shaped natural rubber, etc. are used as the elastic members for three-dimensional gathers, and for the three-dimensional gather sheet, a water-repellent or liquid-impermeable nonwoven fabric formed of hydrophobic fibers, such as a spunbond nonwoven fabric, a meltblown nonwoven fabric, or a composite nonwoven fabric formed by laminating spunbond/meltblown/spunbond, etc. are used.

<Top sheet>
The top sheet 10 may be formed from a substrate having liquid permeability that allows bodily fluids to move to the absorbent 30, and may be formed from a material such as a nonwoven fabric such as an air-through nonwoven fabric, a thermal bond nonwoven fabric, or a spunbond nonwoven fabric, a composite nonwoven fabric in which thermal bond/spunbond are laminated, a foam film such as urethane foam, or a composite sheet in which these are laminated. In addition, the top sheet 10 may be embossed or perforated on the surface in order to improve liquid permeability. As a method for performing these embossing and perforation processes, any known method may be used without limitation. In addition, in order to reduce irritation to the skin, the top sheet 10 may contain lotion, antioxidant, anti-inflammatory component, pH adjuster, antibacterial agent, moisturizer, etc.
From the viewpoints of strength, processability, and liquid return, the basis weight of the top sheet 10 is preferably 18 g/m ² or more and 40 g/m ² or less. There are no particular limitations on the shape of the top sheet 10, as long as it has a shape that covers the absorbent body 30 and is necessary to guide bodily fluids to the absorbent body 30 without leakage.

<Back seat>
The back sheet 20 may be formed using a liquid-impermeable substrate that prevents the body fluid held by the absorber 30 from wetting clothing, and is formed from a material such as a resin film or a composite sheet in which a resin film and a nonwoven fabric are laminated. The nonwoven fabric used in the composite sheet is not particularly limited in terms of the manufacturing method, and examples thereof include spunbond nonwoven fabric, meltblown nonwoven fabric, composite nonwoven fabric in which spunbond/meltblown or spunbond/meltblown/spunbond are laminated, and composite materials thereof. Examples of the resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, and composite films of polyethylene and polypropylene.

From the viewpoint of strength and processability, the basis weight of the back sheet 20 is preferably 15 g/m2 or ^more and 60 g/m2 or ^less . In order to prevent stuffiness during wearing, it is preferable that the back sheet 20 has breathability. In order to provide the back sheet 20 with breathability, for example, a filler may be blended into the resin film of the base material, or the back sheet 20 may be embossed. An example of the filler is calcium carbonate, and the blending method may be a known method without any restrictions.

<Apertured film>
In the present invention, an apertured film 70 having a plurality of funnel-shaped apertures is disposed between the top sheet 10 and the absorbent body 30 .
The perforated film 70 preferably has liquid permeability and liquid diffusibility such that bodily fluids move to the absorbent 30. The shape of the perforated film 70 is not particularly limited, but from the viewpoint of strength and processability, the basis weight of the perforated film 70 is preferably 20 g/m ² or more and 60 g/m ² or less, and more preferably 23 g/m ² or more and 30 g/m ² or less. From the viewpoint of liquid permeability, the number of openings is preferably 50/cm ² or more. Furthermore, from the viewpoint of liquid diffusibility, the opening diameter is preferably 2 mm or less, and more preferably 0.50 mm or more and 0.65 mm or less. By setting the number of openings, opening diameter and basis weight of the perforated film 70 within the above ranges, a perforated film 70 excellent in strength and processability, and excellent in liquid permeability and liquid diffusibility can be obtained. The perforated film 70 is made of a material such as polyethylene, for example.

As shown in FIG. 3, the perforated film 70 has perforations in the thickness direction, with the perforation diameter L1 being small on one side and the perforation diameter L2 being large on the other side. Conventional perforated films used in absorbent articles are arranged so that the perforations on the side with the smaller perforation diameter of the funnel, i.e., the side with the perforation diameter L1, face the absorbent body side, but the perforated film 70 of the present invention is arranged so that the perforations on the side with the perforation diameter L2 face the absorbent body 30 side. This makes it possible to obtain an absorbent article 1 that is excellent not only in permeation into the lower absorbent body 30 but also in diffusion in the lateral direction (front, back, left, right). In addition, from the viewpoint of liquid diffusion, it is preferable that the difference between the perforation diameter L2 on one side with the larger perforation diameter and the perforation diameter L1 on the other side with the smaller perforation diameter is 0.03 mm or more and 0.15 mm or less.

<Absorbent>
In the absorbent article 1 of the present invention, the longest width dimension LO of the absorbent body 30 in the longitudinal direction is preferably 100 mm or more and 800 mm or less, and more preferably 150 mm or more and 500 mm or less. The longest width dimension WO of the absorbent body 30 in the width direction is preferably 50 mm or more and 500 mm or less, and more preferably 70 mm or more and 105 mm or less. As shown in Fig. 2, the absorbent body 30 of the present invention may be two-layered, consisting of an upper absorbent body 301 located on the skin contact side and a lower absorbent body 302 located on the non-skin contact side, and a carrier sheet 50 may be disposed between the upper absorbent body 301 and the lower absorbent body 302.

(Absorbent Fiber)
The absorbent body 30 contains absorbent fibers as a base material and a superabsorbent polymer (SAP).
The absorbent fiber is not particularly limited as long as it is generally used in absorbent articles such as sanitary napkins, paper diapers, and urine pads, and examples thereof include fluff pulp, cotton, rayon, acetate, tissue, absorbent paper, hydrophilic nonwoven fabric, etc. Among these, fluff pulp is preferably used from the viewpoint of absorbency. Examples of fluff pulp include wood pulp (e.g., coniferous bleached kraft pulp (N-BKP) such as southern pine and Douglas fir), synthetic fiber, resin fiber, non-wood pulp, etc., which are defibrated into a cotton-like state. When fluff pulp is used as the absorbent fiber as the base material for the absorbent body 30, the basis weight of the absorbent fiber is preferably 100 g/m ² or more and 800 g/m ² or less, and more preferably 325 g/m ² or more and 615 g/m ² or less. This allows more body fluid to be absorbed without impairing the feel on the skin.

(Superabsorbent polymer)
There are no particular limitations on the superabsorbent polymer of the absorbent body 30 as long as it can absorb body fluids and prevent backflow, and it is possible to use materials formed from sodium polyacrylate, polyaspartate, (starch-acrylic acid) graft copolymer, (acrylic acid-vinyl alcohol) copolymer, (isobutylene-maleic anhydride) copolymer, saponification products thereof, etc. Among these, sodium polyacrylate is preferred from the viewpoint of absorption per weight.

The basis weight of the SAP contained in the absorbent body 30 is preferably 240 g/m ² or more and 450 g/m ² or less, and more preferably 245 g/m ² or more and 445 g/m ² or less. By setting the basis weight within the above numerical range, gel blocking in the absorbent body 30 can be prevented, and the absorbent body 30 can absorb a large amount of body fluid.
In addition, in the absorbent body 30, the ratio of the weight of superabsorbent polymer to the weight of fluff pulp, i.e., weight of superabsorbent polymer/weight of fluff pulp x 100 (%), is preferably 40% or more and 120% or less, and more preferably 50% or more and 100% or less.

In the absorbent body 30, the absorbent fibers and SAP may be in the form of a mixture of SAP particles in absorbent fibers, or may be an SAP sheet with SAP particles fixed between absorbent fibers. The absorbent body 30 may be wrapped in a carrier sheet 50 to prevent leakage of the SAP particles and to stabilize the shape of the absorbent body 30. The base material of the carrier sheet 50 may be any material that has hydrophilicity, and examples of the base material include tissue, absorbent paper, and hydrophilic nonwoven fabrics such as airlaid nonwoven fabrics. When multiple carrier sheets 50 are provided, the base materials of the multiple carrier sheets 50 may be the same or different.

<Second seat>
As shown in FIG. 2, a liquid-diffusing second sheet 40 is preferably disposed between the top sheet 10 and the perforated film 70 in order to improve the liquid diffusion of the absorbent article 1, suppress the hardness of the perforated film 70, and improve the feel. The base material of the second sheet 40 may be any material that has a faster body fluid permeation rate than the top sheet 10 and quickly diffuses body fluid into the absorbent body 30, and is preferably, for example, a hydrophilic nonwoven fabric, particularly an air-through nonwoven fabric. The thickness of the second sheet 40 is preferably 0.1 mm or more, and the basis weight is preferably 10 g/m ² or more and 60 g/m ² or less, and more preferably 15 g/m 2 or more and 40 g/m ² or less. If the thickness is less than 0.1 mm, or the basis weight ^{is less than 10 g/m 2 or} more than 60 g/m ² , the liquid is not sufficiently diffused over the entire upper surface of the absorbent body 30. The shape of the second sheet 40 is not particularly limited, but it is preferable that the second sheet 40 has a shape that can completely cover the surface of the absorbent body 30 so that bodily fluids are diffused throughout the absorbent body 30 .

Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments and examples. It will be clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that forms incorporating such modifications or improvements can also be included in the technical scope of the present invention.

The present invention will be described in detail below with reference to examples. Note that the present invention is not limited to the examples shown below.

(Creation of absorbent articles)
The absorbent body was made by mixing 6g of SAP with 7g of fluff pulp as a base material, an air-through nonwoven fabric (basis weight 25g/ ^m2 ) was used as a top sheet, a breathable polyethylene sheet (basis weight 32g/ ^m2 ) was used as a liquid-impermeable back sheet, an air-through nonwoven fabric (basis weight 30g/ ^m2 ) was used as a second sheet, a composite nonwoven fabric (basis weight 15g/ ^m2 ) laminated with spunbond/meltblown/spunbond was used as a three-dimensional gather, and upper and lower carrier sheets were used. In addition, an apertured film (basis weight 26g/ ^m2 ) was placed under the second sheet, with the side with the smaller aperture diameter as the second sheet side, the dimensions of the absorbent article were 273mm in the longitudinal direction and 105mm in the width, and the dimensions of the absorbent body were 220mm in the longitudinal direction and 71mm in the width, which was used as a sample of the embodiment.
In Comparative Example 1, an absorbent article was prepared in the same manner as in Examples, except that no perforated film was inserted, and this was used as a sample of Comparative Example 1. In Comparative Example 2, an absorbent article was prepared in the same manner as in Examples, except that a perforated film (basis weight 26 g/m ² ) was placed under the second sheet, with the side with the larger perforation diameter facing the second sheet, and this was used as a sample of Comparative Example 2.

(Skin feel of absorbent article surface)
Eight panelists evaluated the feel of the surface of the absorbent article. When six or more but eight evaluators felt that the surface was soft, the rating was "○", when three or more but five evaluators felt that the surface was soft, the rating was "△", and when one or two evaluators felt that the surface was soft, or when no evaluators felt that the surface was soft, the rating was "×". The results are shown in Table 1.

(Absorption rate 3 times method)
A measuring tool with a bottom area of 16.8 ^cm2 , a hole with an inner diameter of 19 mm in the center, and a weight of 755.6 g was placed on the center of the absorbent article in the longitudinal and width directions, and 20 ml of saline was dropped from the hole at the top. The time was measured from the time the saline contacted the absorbent article to the time when the liquid was completely absorbed into the circumference of the center circle of the tool (first time). The same time was then measured after 3 minutes had elapsed (second time), and the third time was measured in the same manner. The results of the first measurement, as well as the results of each of the three measurements and the total are shown in Table 1.

(Amount of liquid returned)
With the top sheet facing up, 120 ml of saline was poured towards the centre of the absorbent, and after leaving it for 10 minutes, a filter paper (Advantec No. 2 filter paper, diameter 55 mm) whose weight had been measured in advance was placed on the area where the saline was absorbed, and a weight of 35 kgf/ ^cm2 was placed on top of it. After 30 seconds, the weight of the filter paper was measured, and the difference in the weight of the filter paper was taken as the amount of liquid return. The results are shown in Table 1.

(Wetting and Spreading Properties)
With the top sheet facing up, 120 ml of saline was poured toward the center of the absorbent body, and the time it took for the saline to spread 10 cm from the absorption site in the longitudinal direction of the product was measured to evaluate wettability. The results are shown in Table 1.

From the results in Table 1, Comparative Example 1, which does not include a perforated film, had a poor surface feel, was inferior in lateral diffusion and absorption speed of simulated urine (physiological saline solution), and had a large amount of liquid returning. Comparative Example 2, which includes a perforated film but has a larger pore size facing the skin, had a good surface feel and had a smaller amount of liquid returning than Comparative Example 1, but was inferior in lateral diffusion and absorption speed, and in particular had a slower absorption speed than Comparative Example 1.
On the other hand, it was found that the examples in which the porous film with smaller pores faced the skin side had a pleasant surface feel, excellent lateral diffusion and absorption speed, and were less susceptible to liquid return.
Therefore, according to the present invention, an absorbent article can be provided that, when it receives liquid from urination or the like, quickly wets and spreads, thereby improving diffusion properties and liquid permeability, and improving prevention of liquid backflow.

REFERENCE SIGNS LIST 1 absorbent article 10 top sheet 20 back sheet 30, 301, 302 absorbent body 40 second sheet 50 carrier sheet 60 three-dimensional gather 70 perforated film

Claims (1)

The device has a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet,
An absorbent article in which an apertured film having a plurality of funnel-shaped apertures is disposed between the top sheet and the absorbent body,
the perforated film has perforations in a thickness direction, one surface of which has a smaller perforation diameter and the other surface of which has a larger perforation diameter, the perforations being arranged so that the perforations on the side of the larger perforation diameter face the absorbent body;
the aperture diameter of the porous film on one side having a larger aperture diameter and the aperture diameter of the porous film on the other side having a smaller aperture diameter are both 0.50 mm or more and 0.65 mm or less, and the basis weight is 20 g/m2 or ^more and 60 g/m2 ^or less,
a difference between the aperture diameter of the one surface having a larger aperture diameter and the aperture diameter of the other surface having a smaller aperture diameter is 0.03 mm or more and 0.15 mm or less;
A liquid-dispersible second sheet is disposed between the top sheet and the perforated film,
An absorbent article, characterized in that the second sheet has a basis weight of 10 g/m2 or ^more and 60 g/m2 ^or less , and the shape of the second sheet is such that it can completely cover the surface of the absorbent body .

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