JP2023129135A - Absorbent article - Google Patents

Abstract

To provide an absorbent article which is easily permeated in a worn state and less likely to cause humidity with moisture vapor.SOLUTION: An absorbent article 10 comprises: an absorbent core 13: a skin-side sheet positioned on the skin side of the absorbent core 13; and a non-skin-side sheet made of one or more sheets positioned on the non skin side of the absorbent core 13. The sheet materials constituting the non-skin-side sheet are all made of fiber sheets. In the absorbent core 13, slit-like openings 14 through the thickness direction of the absorbent core 13 are bored. The total sum of the opening areas of the slit-like openings 14 in a plane view of the absorbent core 13 is desirably 5-30% with respect to an apparent area of the absorbent core 13.SELECTED DRAWING: Figure 1

Description

The present invention relates to absorbent articles.

In absorbent articles such as diapers and napkins, liquid-impermeable films are used as barrier materials for body fluids such as urine and blood, and films that are made moisture permeable (hereinafter also referred to as "moisture permeable films"). ) is used. When an absorbent article is equipped with a moisture-permeable film as the back sheet of the absorbent article, sweat generated from the wearer's body and water vapor generated from excrement absorbed by the absorbent body are transported to the outside through the back sheet. This has the advantage that stuffiness caused by water vapor is less likely to occur when the article is worn.

In recent years, liquid-impermeable nonwoven fabrics have been proposed as backsheets in place of moisture-permeable films. Since the back sheet made of nonwoven fabric has higher moisture permeability than a moisture permeable film, stuffiness caused by water vapor is less likely to occur when the absorbent article is attached.

For example, Patent Document 1 proposes a nonwoven back sheet formed by melt blowing. The nonwoven backsheet has a basis weight of about 3 g/m ² to about 60 g/m ² and an air permeability of at least about 15 cm ³ /cm ² /sec. Further, this nonwoven fabric back sheet is composed of fine fibers having an average fiber diameter of about 3 μm to about 10 μm.
Patent Document 2 proposes the use of a melt-blown nonwoven fabric as a back sheet, which is composed of a fiber aggregate made of fibers with an average fiber diameter of less than 1.5 μm and containing a silicone compound and a polyolefin such as polypropylene as a main component. has been done.

Special Publication No. 2003-527892 JP2017-089070A

Using a nonwoven fabric as the back sheet of an absorbent article has the advantage that stuffiness caused by water vapor is less likely to occur when the absorbent article is worn. There is a need to prevent stuffiness.
Therefore, an object of the present invention is to provide an absorbent article that is more inhibited from causing stuffiness when worn than conventional absorbent articles.

The present invention provides a non-skin side sheet consisting of an absorbent core, a skin-side sheet located closer to the skin than the absorbent core, and one or more sheets located closer to the non-skin side than the absorbent core. and has
All of the sheet materials constituting the non-skin side sheet are made of fiber sheets,
The present invention provides an absorbent article in which the absorbent core is provided with a slit-shaped opening that passes through the thickness direction of the absorbent core.

According to the present invention, an absorbent article is provided that has high air permeability when worn and is less prone to stuffiness caused by water vapor.

FIG. 1 is a partially cutaway plan view showing one embodiment of the absorbent article of the present invention. FIG. 2 is a sectional view taken along line II-II in FIG.

The present invention will be described below based on preferred embodiments thereof with reference to the drawings. An embodiment of the absorbent article of the present invention is shown in FIGS. 1 and 2. FIG.
The absorbent article 10 shown in FIGS. 1 and 2 has a vertically elongated shape with a vertical direction are doing. The absorbent article 10 has a crotch region disposed in the wearer's crotch region, and a ventral region and a dorsal region extending in front and behind the crotch region. The crotch area has an excretory part facing part that is arranged opposite to the wearer's excretory part when the absorbent article 10 is worn, and the excretory part facing part is usually located at the longitudinal center of the absorbent article or the part thereof. Located nearby.

The absorbent article 10 includes an absorbent core 13, a skin-side sheet 11 located closer to the skin than the absorbent core 13, and a non-skin-side sheet 12 located closer to the non-skin than the absorbent core 13. In this specification, the "skin side" refers to the side facing the wearer's body when the absorbent article is worn. The "non-skin side" refers to the side opposite to the skin side across the absorbent core when the absorbent article is worn.

The skin-side sheet 11 is a general term for all sheet materials located closer to the skin than the absorbent core 13. The skin side sheet 11 is made of a single sheet material or a laminate of a plurality of sheet materials. In either case, each sheet material is preferably composed of a fiber sheet, and the skin-side sheet 11 as a whole is preferably liquid-permeable. As long as the skin-side sheet 11 has liquid permeability as a whole, it is permissible for a part of the sheet material constituting the skin-side sheet 11 to include a sheet material other than a fiber sheet, such as a perforated film. Ru.

The non-skin side sheet 12 is a general term for all sheet materials located on the non-skin side of the absorbent core 13. Like the skin side sheet 11, the non-skin side sheet 12 is also made of a single sheet material or a laminate of a plurality of sheet materials. In either case, each sheet material is preferably composed of a fiber sheet, and the non-skin side sheet 12 is preferably breathable as a whole. In particular, it is preferable that the non-skin side sheet 12 does not include a liquid-impermeable film as the sheet material constituting it, from the viewpoint of effectively suppressing the occurrence of stuffiness when the absorbent article 10 is worn.

When the entire area of the absorbent core 13 is covered with a core wrap sheet material (not shown), the sheet material constituting the skin side sheet 11 is located on the skin side of the absorbent core 13 out of the core wrap sheet material. (hereinafter, this part will be referred to as the "skin-side first sheet material"), which is located further on the skin side than the skin-side first sheet material, and which is located on the wearer's body when the absorbent article 10 is worn. There may be two skin-side second sheet materials that are in contact with the body of the patient. That is, the skin-side sheet 11 may be configured from a laminated structure of a first skin-side sheet material and a second skin-side sheet material. The two sheets of material are only placed one on top of the other or are partially joined.

When the skin-side sheet 11 is composed of a laminated structure of a first skin-side sheet material and a second skin-side sheet material, the sheet material located closest to the skin-facing surface of the wearer when the absorbent article 10 is worn is A certain skin-side second sheet material is generally called a top sheet. As the top sheet, a sheet having liquid permeability, such as a nonwoven fabric or a perforated film, can be used. The surface sheet may have an uneven shape on its skin-facing surface side. For example, a plurality of convex portions can be formed in a scattered manner on the skin-facing surface side of the top sheet. Alternatively, ridges and grooves extending in one direction may be alternately formed on the skin-facing surface of the top sheet. For such purposes, the top sheet can also be formed using two or more nonwoven fabrics.

On the other hand, when the entire area of the absorbent core 13 is covered with a core wrap sheet material (not shown), the sheet material constituting the non-skin side sheet 12 is the non-covered part of the absorbent core 13 out of the core wrap sheet material. A portion located on the skin side (hereinafter, this portion will be referred to as "non-skin side first sheet material"), and an absorbent article located further on the non-skin side than the non-skin side first sheet material. There may be two non-skin side second sheet materials which are sheet materials facing outward in the wearing state of No. 10. That is, the non-skin side sheet 12 may be configured from a laminated structure of a first non-skin side sheet material and a second non-skin side sheet material. The two sheets of material are only placed one on top of the other or are partially joined.

When the non-skin side sheet 12 is composed of a laminated structure of a non-skin side first sheet material and a non-skin side second sheet material, the sheet located on the farthest side from the wearer's skin when the absorbent article 10 is attached. The second sheet material on the non-skin side is generally called a back sheet. Details of the back sheet will be described later.

The absorbent core 13 is, for example, a stack of hydrophilic fibers such as cellulose including pulp, a mixed stack of the hydrophilic fibers and an absorbent polymer, a pile of absorbent polymers, or two absorbent sheets. It is composed of a laminated structure with an absorbent polymer supported between them. As described above, the absorbent core 13 may have at least its skin-facing surface covered with a liquid-permeable core wrap sheet material (not shown), and the entire surface including the skin-facing surface and the non-skin-facing surface. may be covered with a core wrap sheet material (not shown). As the core wrap sheet material, for example, thin paper made of hydrophilic fibers, nonwoven fabric having liquid permeability, etc. can be used.

In addition to the above-mentioned skin-side sheet 11, non-skin-side sheet 12, and absorbent core 13, the absorbent article 10 may include a material along the longitudinal direction X on the skin-facing surface side, depending on the specific use of the absorbent article 10. Leak-proof cuffs (not shown) extending along the longitudinal direction X may be disposed on both sides. Leakproof cuffs generally include a proximal end and a free end. The leak-proof cuff has a base end on the skin-facing surface side of the absorbent article 10 and stands up from the skin-facing surface side. The leak-proof cuff is made of a liquid-resistant or water-repellent material that is breathable. An elastic member made of rubber thread or the like may be disposed in a stretched state at or near the free end of the leak-proof cuff. By contracting this elastic member when the absorbent article 10 is worn, the leak-proof cuff comes to stand up toward the wearer's body, and the liquid excreted onto the skin-side sheet 11 is transferred to the skin-side sheet 11. Leaking along the top and outward in the lateral direction Y of the absorbent article 10 is effectively prevented.

The absorbent article 10 may further have an adhesive layer on the non-skin facing surface. The adhesive layer is used to fix the absorbent article 10 to underwear or another absorbent article when the absorbent article 10 is attached.

Examples of absorbent articles having the above structure include, but are not limited to, expandable disposable diapers, pants-type disposable diapers, sanitary napkins, incontinence pads, and auxiliary pads attached to the inside of disposable diapers. do not have.

As shown in FIGS. 1 and 2, the absorbent core 13 has a pair of side edges 13a, 13a extending in the vertical direction X, and a pair of end edges 13b, 13b extending in the horizontal direction Y. The side edge 13a is a straight line, and both side edges 13a, 13a extend parallel to each other.
The absorbent core 13 is provided with a slit-shaped opening 14 passing through the absorbent core 13 in the thickness direction Z. The opening 14 has a long shape in one direction. In the embodiment shown in FIGS. 1 and 2, the opening 14 has an elongated rectangular shape extending in the lateral direction Y. In the embodiment shown in FIGS. A plurality of openings 14 are formed at intervals in the vertical direction X in a region from one end to the other end in the vertical direction.
By providing the openings 14 penetrating the absorbent core 13, the absorbent article 10 of this embodiment has high breathability when worn, due to the synergistic effect with the back sheet described below, and prevents stuffiness caused by water vapor. Less likely to occur. This will be described in more detail later.

From the viewpoint of further suppressing the occurrence of stuffiness caused by water vapor when the absorbent article 10 is worn, the total opening area of the slit-shaped openings 14 in the absorbent core 13 when viewed from above is determined by the apparent appearance of the absorbent core. It is preferable that it is 5% or more with respect to the area of (hereinafter, this value is also referred to as "aperture ratio").
Further, from the viewpoint of absorbing and retaining a sufficient amount of liquid in the absorbent core 13 and ensuring the shape retention of the absorbent core 13, the aperture ratio of the openings 14 is preferably 30% or less, and 20% or less. It is more preferably at most 10%, even more preferably at most 10%.
In summary, the aperture ratio of the opening 14 is preferably 5% or more and 30% or less, more preferably 5% or more and 20% or less, and even more preferably 5% or more and 10% or less.

Although the aperture ratio of the openings 14 is as described above, the area of each opening 14 may be appropriately set depending on the specific use of the absorbent article 10. When the absorbent article 10 is, for example, a disposable baby diaper, the area of each opening 14 is preferably 1 cm ² or more and 30 cm ² or less, and 3 cm ² or more and 20 cm ^{2 or} less, respectively. It is more preferably 5 cm ² or more and 10 cm ² or less. By setting the area of each opening 14 in this way, the absorbent core 13 absorbs and retains a sufficient amount of liquid, while further suppressing the occurrence of stuffiness caused by water vapor when the absorbent article 10 is attached. can do.

As described above, the opening 14 preferably has a slit-like shape that is long in one direction, that is, an anisotropic shape. Since the opening 14 has such an anisotropic shape, the flexibility of the absorbent core 13 is improved, and the fit of the absorbent article 10 to the wearer's body is improved. Therefore, there is an advantage that it is effective in reducing leakage.
From the viewpoint of making this advantage even more remarkable, the slit-shaped opening 14 has a value of a/b, where the length in the longitudinal direction is a, and the length in the transverse direction orthogonal to the longitudinal direction is b. is preferably 1.5 or more and 15 or less, more preferably 3 or more and 12 or less, even more preferably 5 or more and 10 or less.

When the absorbent core 13 is a mixed fiber stack of hydrophilic fibers such as pulp and a hydrogel material such as an absorbent polymer, the basis weight of the absorbent core 13 is such that when the absorbent article 10 is attached, water vapor From the viewpoint of further suppressing the occurrence of stuffiness caused by the absorbent core 13 and from the viewpoint of absorbing and retaining a sufficient amount of liquid in the absorbent core 13, it is preferably 200 g/m ² or more in the area excluding the opening, and 300 g /m ² or more is more preferable, and even more preferably 400 g/m ² or more.

A non-skin side sheet 12 is arranged on the non-skin facing side of the absorbent core 13. As described above, at least one of the sheet materials constituting the non-skin side sheet 12 is generally called a back sheet. In this embodiment, the back sheet is made of a fiber sheet, particularly a nonwoven fabric. Due to the synergistic effect of configuring the back sheet from a non-woven fabric and providing the openings 14 in the absorbent core 13 described above, the absorbent article 10 of this embodiment has even higher breathability when worn, and is more resistant to water vapor. This makes it even more difficult for stuffiness to occur.
Until now, techniques for using nonwoven fabrics as backsheets for absorbent articles have been known. By using a nonwoven fabric as the back sheet, the water vapor permeability is higher than when using a moisture permeable film, and the occurrence of stuffiness when the absorbent article is worn is suppressed. When the present inventor further investigated an absorbent article using a nonwoven fabric as a back sheet, it was found that by providing an opening 14 in the absorbent core 13, the liquid retained in the absorbent core 13 can be prevented from evaporating. It has been found that the flow of the generated water vapor becomes smoother, and the dissipation of the water vapor through the back sheet made of nonwoven fabric is further promoted. According to the absolute humidity values calculated by the present inventor from garment science literature, the range from 28.3 g/m ³ to 32.8 g/m ³ is classified as the "uncomfortable area", and the range from 23.7 g/m ³ to 28.3 g/m 3 is classified as the "uncomfortable area". Up to ^m3 is classified as a "slightly uncomfortable area." The absolute humidity value of an absorbent article equipped with a moisture-permeable film as a backsheet, which has been conventionally used in the technical field, is 29.5 g/ ^m3 , and an absolute humidity value of an absorbent article equipped with a nonwoven fabric as a backsheet. While the absolute humidity value was 28.9 g/m ³ , in the absorbent article 10 of this embodiment, the absolute humidity value decreased from 27.1 g/m ³ to 27.8 g/m ³ . In other words, the feeling of stuffiness when worn is reduced, making it possible to achieve a more comfortable area than the ``uncomfortable area''.
From the above viewpoint, the back sheet preferably does not contain a film layer including a moisture permeable film, and is preferably composed only of nonwoven fabric.

By increasing the breathability of the nonwoven fabric used as the non-skin side sheet 12 including the back sheet, it becomes possible to make the absorbent article 10 more comfortable to wear. However, the non-skin side sheet 12 including the back sheet is also required to have a function of preventing leakage of the liquid held in the absorbent core 13, and from this point of view, it is desirable that the nonwoven fabric has low liquid permeability. The air permeability and liquid blocking properties of a nonwoven fabric mainly depend on the basis weight of the nonwoven fabric and the thickness of the fibers constituting the nonwoven fabric.

The nonwoven fabric used as the back sheet is composed only of meltblown nonwoven fabrics, or nonwoven fabrics containing meltblown nonwoven fabrics, such as SM nonwoven fabrics (meltblown-spunbond composite nonwoven fabrics), SMS nonwoven fabrics (spunbond-meltblown-spunbond composite nonwoven fabrics), It is preferably composed of an SMMS nonwoven fabric (spunbond-meltblown-meltblown-spunbond composite nonwoven fabric).

Meltblown nonwoven fabric exhibits high liquid blocking properties because its constituent fibers have small fiber diameters due to its manufacturing method. The fiber diameter of the constituent fibers of the melt-blown nonwoven fabric is preferably 0.1 μm or more and 10 μm or less, more preferably 0.3 μm or more and 7 μm or less, and even more preferably 0.5 μm or more and 5 μm or less.

The fiber diameter of the constituent fibers of the melt-blown nonwoven fabric is measured by the following method. A small piece sample is taken from the melt-blown nonwoven fabric, gold vapor deposition is performed on the sample for 2 minutes, and then the fiber diameter is directly measured using a scanning electron microscope for 70 randomly selected fibers. The average value (two significant figures) of the measured values is taken as the fiber diameter of the constituent fibers of the melt-blown nonwoven fabric. When the back sheet is composed of a nonwoven fabric including a meltblown nonwoven fabric such as an SM nonwoven fabric, an SMS nonwoven fabric, and an SMMS nonwoven fabric, the small piece sample is collected at a stage where it can be collected from the meltblown nonwoven fabric among the manufacturing stages of the nonwoven fabric. Alternatively, if possible, the surface of the SMS nonwoven fabric or the like may be observed using a scanning electron microscope, and the fibers of the meltblown nonwoven fabric may be directly observed to measure the fiber diameter.

Whether the nonwoven fabric constituting the back sheet is composed only of meltblown nonwoven fabrics or nonwoven fabrics including meltblown nonwoven fabrics such as SM nonwoven fabrics, SMS nonwoven fabrics, and SMMS nonwoven fabrics, the The basis weight is preferably 1 g/m ² or more, more preferably 5 g/m ² or more, and even more preferably 10 g/m ² or more, from the viewpoint of balancing air permeability and liquid blocking properties. preferable. From the same viewpoint, the basis weight of the meltblown nonwoven fabric is preferably 50 g/m ² or less, more preferably 35 g/m ² or less, and even more preferably 20 g/m ² or less.
To summarize the above, the basis weight of the meltblown nonwoven fabric is preferably 1 g/m ² or more and 50 g/m ² or less, more preferably 5 g/m ² or more and 35 g/m ² or less, and 10 g/m ² or more and 20 g /m ² or less is more preferable.

The basis weight of a melt-blown nonwoven fabric is calculated by dividing the average value of the mass measured for five measurement pieces of at least 10 mm square taken from the nonwoven fabric by the area of the measurement pieces. When the back sheet is composed of a nonwoven fabric including a meltblown nonwoven fabric such as an SM nonwoven fabric, an SMS nonwoven fabric, and an SMMS nonwoven fabric, each layer may be separated using a method such as peeling, and the basis weight of the meltblown nonwoven fabric may be measured. .

Nonwoven fabrics used as backsheets (hereinafter also referred to as "nonwoven backsheets") include a wide variety of fabrics manufactured by various methods. Various methods are known for producing nonwoven fabrics, such as melt blown method, spun bond method, air through method, air laid method, spun lace method, needle punch method, electrospinning method, chemical bond method, and thermal bond method. Nonwoven fabric backsheets include those manufactured by these methods. However, the present invention is not limited to these methods, and nonwoven fabrics produced by methods other than these methods or nonwoven fabrics produced by any combination of these methods may be used. It is desirable that the nonwoven back sheet has high liquid barrier properties, and it is particularly advantageous that it is a meltblown nonwoven fabric or a composite nonwoven fabric having a meltblown layer, which is a nonwoven fabric that easily exhibits this property. Examples of the composite nonwoven fabric having a meltblown layer include SM nonwoven fabric and SMS nonwoven fabric.

When the nonwoven fabric used as the back sheet has a laminated structure of a plurality of nonwoven fabrics, it is preferable that the laminated structure includes at least a spunbond layer and a meltblown layer from the viewpoint of balancing the air permeability and liquid blocking properties of the nonwoven fabric. . That is, the nonwoven fabric is preferably the above-mentioned SM nonwoven fabric or SMS nonwoven fabric. In this case, the ratio of the mass of the spunbond layer to the mass of the nonwoven fabric is preferably 50% by mass or more and 95% by mass or less, from the viewpoint of achieving a high balance between the air permeability and liquid blocking property of the nonwoven fabric. From the same viewpoint, the ratio of the mass of the spunbond layer to the mass of the nonwoven fabric is more preferably 50% by mass or more and 90% by mass or less, even more preferably 50% by mass or more and 85% by mass or less.

On the other hand, the ratio of the mass of the meltblown layer to the mass of the nonwoven fabric is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and 15% by mass or more and 50% by mass. It is more preferable that it is the following.

The constituent fibers of the nonwoven back sheet preferably contain a thermoplastic resin having fiber-forming ability and triglyceride. Various thermoplastic resins having fiber-forming ability are known in the technical field, but in the present invention, it is preferable to use polyolefin resin as the thermoplastic resin from the viewpoint of obtaining a nonwoven fabric with high barrier properties against liquids. preferable.

As the polyolefin resin, for example, a homopolymer or copolymer of a lower olefin such as ethylene or propylene can be used. Specific examples include polyethylene, polypropylene, and ethylene-α olefin copolymers.
Examples of polyethylene include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene.
Examples of polypropylene include isotactic polypropylene and syndiotactic polypropylene. Moreover, low stereoregularity homopolypropylene can also be used as the polypropylene. Low stereoregular homopolypropylene refers to homopolypropylene with a mesopentad fraction (mmmm [%]) of 90% or less as measured by ¹³ C-NMR, which is an indicator of stereoregularity.
Examples of the ethylene-α-olefin copolymer include copolymers of ethylene and α-olefins such as propylene, 1-butene, 1-pentene, and 1-hexene. Examples of copolymers include random copolymers, block copolymers, and graft copolymers. In particular, it is preferable to use a random copolymer of ethylene and propylene (hereinafter also referred to as "random propylene copolymer").
Among these polyolefin resins, it is preferable to use polypropylene and polyolefins containing propylene as a copolymer component from the viewpoint of high fiber-forming ability and high liquid barrier properties of the resulting nonwoven fabric.
Moreover, it is also preferable that the polyolefin resin is a blend of homopolypropylene and a random propylene copolymer or a low stereoregular homopolypropylene.

The fibers constituting the nonwoven fabric back sheet may contain only one kind of the above-mentioned polyolefin resin, or may contain two or more kinds of polyolefin resins.
The fibers constituting the nonwoven fabric back sheet may contain only the above-mentioned polyolefin resin as its constituent resin, or may contain other thermoplastic resins in addition to the polyolefin resin. In the latter case, it is preferable that the fibers contain at least 50% by mass of the above-mentioned polyolefin resin.

Triglyceride, which is another component contained in the fibers constituting the nonwoven back sheet, is used to lower the surface tension of the fibers constituting the nonwoven fabric and improve the barrier properties of the nonwoven fabric against liquids. The triglyceride may exist in a state attached to the surface of the fiber or may be kneaded into the resin constituting the fiber.

As the triglyceride, triglycerides derived from saturated fatty acids, triglycerides derived from unsaturated fatty acids, triglycerides derived from saturated fatty acids and unsaturated fatty acids, and the like can be used. In either case, the number of carbon atoms in the fatty acid can be, for example, 12 or more and 24 or less. From the viewpoint of further enhancing the barrier properties of the nonwoven fabric against liquids, the number of carbon atoms in the fatty acid is preferably 14 or more and 22 or less, more preferably 16 or more and 20 or less.
Only one type of triglyceride may be used, or a mixture of multiple types of triglycerides may be used.
The fibers constituting the nonwoven fabric back sheet may contain only triglycerides as glycerides, or may contain monoglycerides and/or diglycerides in addition to triglycerides as long as the desired effects of the present invention are achieved. Good too. However, from the viewpoint of increasing the liquid barrier properties of the nonwoven back sheet, it is preferable to use only triglyceride as the glyceride.

The triglyceride used in the present invention is preferably one in which the number of carbon atoms in fatty acid residues is adjusted. By using such a triglyceride, the barrier properties of the nonwoven back sheet against liquids can be increased. Specifically, it is preferable to use the following (a) or (b) as the triglyceride.
(a) A triglyceride comprising a mixture of a triglyceride containing in one molecule at least a group derived from a fatty acid having 16 carbon atoms and a triglyceride containing at least a group originating in one molecule from a fatty acid having 18 carbon atoms.
(b) A triglyceride containing, in one molecule, at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms.

In the case of (a), two or more types of triglycerides are used. At least one of the multiple types of triglycerides contains in one molecule at least one group derived from a fatty acid having 16 carbon atoms (that is, a saturated fatty acid or an unsaturated fatty acid) (this triglyceride is referred to as a "triglyceride"). 16"). It is preferable that the triglyceride 16 contains at least one group derived from a fatty acid having 16 carbon atoms in one molecule. Triglyceride 16 may contain one group derived from a fatty acid having 16 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride P"), or may contain two groups (this triglyceride is also referred to as "triglyceride P"). (This triglyceride is also referred to as "triglyceride PP."), or it may contain three triglycerides (this triglyceride is also referred to as "triglyceride PPP").
The remaining fatty acid residues in triglyceride P and triglyceride PP are not particularly limited, and may be, for example, residues of saturated fatty acids or unsaturated fatty acids having 12 or more and 24 or less carbon atoms.

The triglyceride 16 may be composed only of triglyceride P, may be composed only of triglyceride PP, or may be composed only of triglyceride PPP.
The triglyceride 16 may be a combination of two or more selected from triglyceride P, triglyceride PP, and triglyceride PPP. For example, triglyceride 16 can be a combination of triglyceride P and triglyceride PP, a combination of triglyceride P and triglyceride PPP, a combination of triglyceride PP and triglyceride PPP, or a combination of triglyceride P, triglyceride PP and triglyceride PPP.

At least one of the plurality of triglycerides in case (a) contains at least one group in one molecule derived from a fatty acid having 18 carbon atoms (that is, a saturated fatty acid or an unsaturated fatty acid). (Triglyceride is also called "triglyceride 18.") Triglyceride 18 preferably contains at least one group derived from a fatty acid having 18 carbon atoms in one molecule. Triglyceride 18 may contain one group derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride S"), or may contain two groups (this triglyceride is also referred to as "triglyceride S"). (This triglyceride is also referred to as "triglyceride SS."), or it may contain three triglycerides (this triglyceride is also referred to as "triglyceride SSS").
The remaining fatty acid residues in triglyceride S and triglyceride SS are not particularly limited, and may be, for example, residues of saturated fatty acids or unsaturated fatty acids having 12 or more and 24 or less carbon atoms.

The triglyceride 18 may be composed only of triglyceride S, may be composed only of triglyceride SS, or may be composed only of triglyceride SSS.
The triglyceride 18 may be a combination of two or more selected from triglyceride S, triglyceride SS, and triglyceride SSS. For example, triglyceride 18 can be a combination of triglyceride S and triglyceride SS, a combination of triglyceride S and triglyceride SSS, a combination of triglyceride SS and triglyceride SSS, or a combination of triglyceride S, triglyceride SS and triglyceride SSS.

In the case of (a), the triglyceride may be composed only of triglyceride 16 and triglyceride 18, or may be composed of other triglycerides in addition to triglyceride 16 and triglyceride 18. Other triglycerides include triglycerides having neither a group derived from a C16 fatty acid nor a group derived from a C18 fatty acid.

Groups derived from fatty acids having 16 carbon atoms were designated as "P", groups derived from fatty acids having 18 carbon atoms were designated as "S", and groups derived from other fatty acids were designated as "X" and "Y". In this case, the combinations of groups derived from fatty acids constituting the triglyceride are PPP (i.e. triglyceride PPP), SSS (i.e. triglyceride SSS), PPX (i.e. triglyceride PP), SSX (i.e. triglyceride SS), PXY (i.e. triglyceride P) and SXY (i.e. triglyceride S). The structures of triglycerides represented by PPP, SSS, PPX, SSX, PXY and SXY are (A) to (L) below.

From the viewpoint of obtaining a nonwoven fabric with even higher barrier properties against liquids, it is preferable to use triglyceride composed only of triglyceride 16 and triglyceride 18.

In case (b), at least one triglyceride can be used. This triglyceride contains in one molecule at least one group derived from a fatty acid with 16 carbon atoms (i.e., saturated fatty acid or unsaturated fatty acid) and is derived from a fatty acid with 18 carbon atoms (i.e., saturated fatty acid or unsaturated fatty acid). It contains at least one group. In particular, the triglyceride must contain at least one group derived from a saturated fatty acid having 16 carbon atoms and at least one group derived from a saturated fatty acid having 18 carbon atoms in one molecule to improve the barrier against liquids. This is preferred in that a nonwoven fabric with even higher properties can be obtained.

In the case of (b), a group derived from a fatty acid having 16 carbon atoms is designated as "P", a group derived from a fatty acid having 18 carbon atoms is designated as "S", and a group derived from other fatty acids is designated as " X'', the combination of aliphatic groups constituting the triglyceride is SSP, SPP, or SPX. The structure of the triglyceride represented by SPX is any of the following (M) to (O). The same applies to SSP and SPP.

In the case of (b), the triglyceride is limited to those containing at least one group derived from a fatty acid having 16 carbon atoms and at least one group derived from a fatty acid having 18 carbon atoms in one molecule. may be configured. Alternatively, the triglyceride may include a triglyceride containing at least one group derived from a fatty acid having 16 carbon atoms and at least one group derived from a fatty acid having 18 carbon atoms, and other glycerides. good. Other triglycerides include triglycerides that do not have in one molecule either a group derived from a fatty acid having 16 carbon atoms or a group derived from a fatty acid having 18 carbon atoms. From the viewpoint of obtaining a nonwoven fabric with even higher barrier properties against liquids, one molecule contains at least one group derived from a fatty acid having 16 carbon atoms and at least one group derived from a fatty acid having 18 carbon atoms. Preferably, only triglycerides are used.

In the present invention, a combination of (a) and (b) can also be used. Specifically, a combination of triglyceride PPP, triglyceride SSS, and SPX can be used. Alternatively, a combination of triglyceride PPP, triglyceride SSS, and SSP, or a combination of triglyceride PPP, triglyceride SSS, and SPP can also be used. Furthermore, combinations of triglyceride PPX, triglyceride SSX, and triglyceride SPX, combinations of triglyceride PPX, triglyceride SSX, and triglyceride SSP, combinations of triglyceride PPX, triglyceride SSX, and triglyceride SPP, and triglyceride PXY A combination of , triglyceride SXY, and triglyceride SPX, a combination of triglyceride PXY, triglyceride SXY, and triglyceride SSP, and a combination of triglyceride PXY, triglyceride SXY, and triglyceride SPP can also be used.

In either case of (a) or (b) above, the fact that the triglyceride used in the present invention does not contain groups derived from unsaturated fatty acids increases the liquid barrier properties of the nonwoven fabric back sheet. Preferable from this point of view. The term "not containing groups derived from unsaturated fatty acids" includes both cases where no groups derived from unsaturated fatty acids are contained and cases where a small amount of unsaturated fatty acids are unavoidably contained. A case where a small amount of unsaturated fatty acids is unavoidably included means, for example, that the proportion of groups derived from unsaturated fatty acids is based on the total amount of fatty acid-derived groups contained in all triglycerides contained in the fiber. This is the case when it is 2% by mass or less.

In the present invention, it is possible to adjust the proportion of groups derived from fatty acids having 16 carbon atoms and the proportion of groups originating from fatty acids having 18 carbon atoms for all triglycerides contained in the constituent fibers of the nonwoven fabric back sheet. , is preferable from the viewpoint of further increasing the liquid barrier properties of the nonwoven fabric back sheet.

Regarding the proportion of groups derived from fatty acids having 16 carbon atoms, the proportion of groups derived from fatty acids of the nonwoven fabric should be 1% by mass or more based on the total amount of groups derived from fatty acids for all triglycerides contained in the constituent fibers of the nonwoven fabric back sheet. It is preferable from the viewpoint of further increasing the barrier property against the liquid, and more preferably 10% by mass or more, still more preferably 15% by mass or more, even more preferably 20% by mass or more, particularly preferably from the viewpoint of further increasing the barrier property. It is 25% by mass or more.
In addition, the ratio is preferably less than 55% by mass from the viewpoint of further increasing the barrier properties of the nonwoven fabric against liquids, more preferably 50% by mass or less, and even more preferably 45% by mass from the viewpoint of further increasing the barrier properties. % or less.
The proportion is preferably 1% by mass or more and less than 55% by mass, more preferably 10% by mass or more and less than 55% by mass, even more preferably 15% by mass or more and less than 55% by mass, and 20% by mass. % or more and 50% by mass or less, and particularly preferably 25% by mass or more and 45% by mass or less.

Regarding the proportion of groups derived from fatty acids having 18 carbon atoms, the proportion of groups derived from fatty acids of nonwoven fabric should be 5% by mass or more, based on the total amount of groups derived from fatty acids, for all triglycerides contained in the constituent fibers of nonwoven fabric. The content is preferably 35% by mass or more, and even more preferably 45% by mass or more from the viewpoint of further increasing barrier properties. It is even more preferably 50% by mass or more, particularly preferably 55% by mass or more.
Further, the ratio is preferably less than 90% by mass from the viewpoint of further increasing the barrier properties of the nonwoven fabric against liquids, more preferably 70% by mass or less, and even more preferably 65% by mass from the viewpoint of further increasing the barrier properties. % or less.
The proportion is preferably 5% by mass or more and less than 90% by mass, more preferably 35% by mass or more and less than 90% by mass, even more preferably 45% by mass or more and less than 90% by mass, and 50% by mass. % or more and 70% by mass or less, and even more preferably 55% by mass or more and 65% by mass or less.

Regarding the ratio of groups derived from fatty acids having 16 carbon atoms to those derived from fatty acids having 18 carbon atoms, groups derived from fatty acids having 16 carbon atoms contained in all triglycerides contained in the fibers are It is preferable that the mass ratio (C18/C16) of groups derived from a fatty acid having 18 carbon atoms to the nonwoven fabric is 1.0 or more and 15.0 or less from the viewpoint of further increasing the barrier properties of the nonwoven fabric against liquids. In order to make this advantage even more remarkable, the mass ratio (C18/C16) of the group derived from a fatty acid having 18 carbon atoms to the group derived from a fatty acid having 16 carbon atoms should be 1.2 or more and 10. It is more preferably 0 or less, even more preferably 1.3 or more and 5.0 or less, and even more preferably 1.3 or more and 2.7 or less.

Based on the total amount of fatty acid-derived groups contained in all triglycerides contained in the fiber, the respective proportions of groups derived from fatty acids with 16 carbon atoms and groups derived from fatty acids with 18 carbon atoms are as follows. It is measured by the following method.
A good solvent for triglycerides, such as toluene, is used to extract triglycerides present on the surface of the fibers constituting the nonwoven fabric.
The ester bonds in the extracted triglycerides are hydrolyzed with an alkali, and the methyl-esterified fatty acids are quantitatively analyzed using gas chromatography.

Note that whether or not alkyl chains having different numbers of carbon atoms exist in one molecule of triglyceride can be determined by TOF-MS (time-of-flight mass spectrometry). Specifically, the molecular weight distribution of triglyceride is measured by TOF-MS, and it is determined from the molecular weight of one molecule whether or not the molecule contains an alkyl group having a different number of carbon atoms. Whether or not alkyl chains having different numbers of carbon atoms exist in one molecule of compounds having the same molecular weight can be determined using a tandem mass spectrometer (MS/MS) as a mass spectrometer. The first mass separator selects a specific ion, and the second mass separator separates and detects fragment ions generated by colliding with an inert gas, thereby identifying the ions.

In the nonwoven fabric back sheet used in the present invention, the triglyceride satisfying (a) and/or the triglyceride satisfying (b) described above is contained in an amount of 1% by mass or more based on the triglyceride-containing fibers. The content is preferably 2% by mass or more, and even more preferably 3% by mass or more from the viewpoint of further increasing the barrier property of the sheet against liquids.
The ratio of the triglyceride to the triglyceride-containing fiber is preferably 30% by mass or less, from the viewpoint of improving spinnability and the texture of the nonwoven fabric back sheet, more preferably 20% by mass or less, More preferably, it is 15% by mass or less.
The proportion of the triglyceride to the triglyceride-containing fiber is preferably 1% by mass or more and less than 30% by mass, more preferably 2% by mass or more and 20% by mass or less, and 3% by mass or more and 15% by mass or less. It is more preferable that there be.

An example of a method for incorporating triglyceride into the fibers constituting the nonwoven fabric back sheet is a method in which a thermoplastic resin constituting the fibers and triglyceride are melt-kneaded and the triglyceride is kneaded into the thermoplastic resin. However, the method is not limited to this, and triglycerides may be added to the fibers by other methods.

The nonwoven fabric back sheet may be composed only of fibers containing the polyolefin resin and the above-mentioned triglyceride, or may be composed of the fibers and other fibers. In the latter case, the nonwoven back sheet may be composed of a blend of the fibers and other fibers, or it may be composed of a laminate of a layer containing only the fibers and a layer containing only the other fibers. You can also do that. For example, the nonwoven fabric backsheet can be constructed from a laminate of a meltblown layer containing only the fibers and spunbond layers disposed on each side of the meltblown layer and containing only the other fibers. If the nonwoven fabric backsheet is composed of the fibers and other fibers, no matter what form the nonwoven fabric backsheet has, from the viewpoint of increasing the barrier properties of the nonwoven fabric against liquids, the nonwoven fabric The proportion of the fibers in the back sheet is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiment, when a core wrap sheet material covering the absorbent core 13 is disposed on the surface of the absorbent core 13, the opening provided in the absorbent core 13 in the core wrap sheet material An opening having the same shape and size as the opening 14 may be provided at a position corresponding to the portion 14.

Furthermore, the shape and arrangement of the openings 14 provided in the absorbent core 13 are not limited to those shown in FIGS. 1 and 2. For example, they can be of any isotropic shape, circular, star-shaped, heart-shaped, etc., and they do not have to be arranged at equal intervals, and they can be arranged concentrated in the urinary area.

Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the scope of the invention is not limited to such examples. Unless otherwise specified, "%" means "% by mass".

[Example 1]
(1) Production of masterbatch Propylene homopolymer (manufactured by Lyondelbasel, HP461Y, hereinafter referred to as "homo PP") and triglyceride were weighed so that the mass ratio was 90/10, and a twin-screw extruder (Toyo Seiki Co., Ltd.) and kneaded it to prepare a masterbatch.
Extremely hardened palm oil (manufactured by Ueda Oil Co., Ltd.) was used as the triglyceride. This triglyceride was a mixture of a plurality of triglycerides, each having a group derived from a saturated fatty acid having a different number of carbon atoms. In this triglyceride, the proportion of groups derived from C14 saturated fatty acids was 1%, the proportion of groups derived from C16 saturated fatty acids was 42%, and the proportion of groups derived from C18 saturated fatty acids was 57%.
(2) Production of meltblown nonwoven fabric A meltblown nonwoven fabric was produced using the obtained masterbatch as a raw material. The basis weight of the melt-blown nonwoven fabric thus obtained was 15 g/m ² , and the fiber diameter of the constituent fibers was 0.7 μm. The basis weight of the nonwoven fabric was determined by dividing the average value of the masses measured using 10 pieces of 16 cm x 16 cm randomly sampled from the nonwoven fabric by 0.0256.
(3) Production of nonwoven fabric back sheet By laminating and integrating spunbond nonwoven fabrics with a basis weight of 9 g/m ² on each side of this melt-blown nonwoven fabric, it has a three-layer structure with a basis weight of 33 g/m ² An SMS nonwoven fabric was obtained. The spunbond nonwoven fabric was composed of PP fibers with a fiber diameter of 20 μm. This SMS nonwoven fabric was used as a back sheet.
(4) Manufacture of absorbent article The absorbent core shown below was manufactured using a mixed fiber stack consisting of flap pulp and particles of absorbent polymer made of crosslinked acrylate. The dimensions of the absorbent core were 10 cm long and 10 cm wide, which are dimensions suitable for measuring the humidity inside the article. The basis weight of the absorbent core was 490 g/m ^{2 in total with 350 g/m 2} of pulp and 140 g/m ^{2 of} polymer. A rectangular opening with a length of 1 cm and a width of 8 cm was formed at one location in the center of the absorbent core. The aperture ratio was 8%.
An absorbent core is placed on the back sheet (non-skin side sheet) made of the SMS nonwoven fabric obtained in (3) above, and a top sheet (skin side sheet) made of air-through nonwoven fabric is placed on top of the back sheet (non-skin side sheet). By joining the top sheet and back sheet extending from the periphery of the core, a model absorbent article with dimensions suitable for measuring the humidity inside the article was obtained.

[Example 2]
In Example 1, triglyceride was not blended into the constituent fibers of the melt-blown nonwoven fabric in the SMS nonwoven fabric constituting the back sheet. An absorbent article was obtained in the same manner as in Example 1 except for this.

[Example 3]
In Example 1, triglyceride was not blended into the constituent fibers of the melt-blown nonwoven fabric in the SMS nonwoven fabric constituting the back sheet. Two rectangular openings were formed in the center of the absorbent core. The interval between the openings was 5 cm. An absorbent article was obtained in the same manner as in Example 1 except for the above. The aperture ratio was 16%.

[Example 4]
In Example 1, triglyceride was not blended into the constituent fibers of the melt-blown nonwoven fabric in the SMS nonwoven fabric constituting the back sheet. Three rectangular openings were formed in the center of the absorbent core. The interval between the openings was 2 cm. An absorbent article was obtained in the same manner as in Example 1 except for the above. The aperture ratio was 24%.

[Comparative example 1]
In Example 1, a porous moisture-permeable film made of polyethylene resin was used as the back sheet. Further, no opening was provided in the absorbent core. An absorbent article was obtained in the same manner as in Example 1 except for the above.

[Comparative example 2]
In Example 1, a porous moisture-permeable film made of polyethylene resin was used as the back sheet. Additionally, three openings were formed in the center of the absorbent core. An absorbent article was obtained in the same manner as in Example 1 except for the above.

[Comparative example 3]
In Example 1, triglyceride was not blended into the constituent fibers of the melt-blown nonwoven fabric in the SMS nonwoven fabric constituting the back sheet. Further, no opening was provided in the absorbent core. An absorbent article was obtained in the same manner as in Example 1 except for the above.

〔evaluation〕
Regarding the absorbent articles obtained in Examples and Comparative Examples, the humidity inside the article and the amount of liquid returned were measured using the following methods. Furthermore, the bleed-out prevention properties were evaluated. The results are shown in Table 1.

[Humidity inside the product]
The temperature of the hot plate of KESF7 (precision rapid thermophysical property measuring device) manufactured by Kato Tech was raised to 33°C. Laurier Slim Guard for night use (registered trademark, manufactured by Kao Corporation), in which 10 g of physiological saline was injected, was placed on a hot plate with the top sheet facing upward, and the amount of water evaporation from the Laurier Slim Guard was approximately constant. I let it acclimate for about an hour. After acclimatization, the absorbent articles of Examples and Comparative Examples (top sheet) were injected with a moisture-permeable film separated from Merry's (registered trademark, manufactured by Kao Corporation), Hygroclone (wireless data logger manufactured by KN Laboratories), and 65 g of artificial urine. (facing downward) and Relief Anshin Tape Type (registered trademark, manufactured by Kao Corporation, surface sheet facing downward) were stacked in this order. With the surroundings fixed with weights so as not to create any gaps, the temperature and humidity data taken 20 minutes later using a hygroclon was converted into absolute humidity (g/m ³ ), and the value was defined as the internal humidity of the article when wet. The internal humidity of the substance during drying was measured under the condition that no artificial urine was injected into the absorbent articles of Examples and Comparative Examples.

[Liquid return amount]
A total of 16 pieces of filter paper 5C (diameter 160 mm) were prepared, and their total mass was measured.
Using a funnel, 50 g of artificial urine was injected into the center of the absorbent article, which was placed horizontally with the top sheet facing upward. The injection rate was 5 g/s. After the injection, the mixture was left to stand for 2 minutes, and then a 10 cm x 10 cm acrylic plate was placed on the top sheet, a 4.5 kg weight was placed on top of the top sheet, and pressure was applied for 3 minutes. Next, the weight and the acrylic plate were removed, and the liquid adhering to the acrylic plate was wiped off. After 30 seconds had elapsed from the removal, the 16 pieces of filter paper were placed on the top sheet, the acrylic plate and the weight were placed thereon, and pressure was applied for 2 minutes. Next, the filter paper, acrylic plate, and weight were removed, and the mass of the filter paper was measured again. The difference in mass of the filter paper was calculated, and the value was taken as the liquid return amount.
In addition, the same operation as above was performed with the amount of artificial urine injected changed to 150 g, and the amount of liquid returned was measured.

[Blooding prevention]
The SMS nonwoven fabrics and moisture permeable films used in the manufacture of the absorbent articles of Examples and Comparative Examples were evaluated for their ability to prevent liquid from seeping out by the following method.
An SMS nonwoven fabric or moisture permeable film cut into 8 cm x 8 cm was placed on a filter paper (manufactured by Advantech Toyo Co., Ltd., No. 2, diameter 70 mm). A dry pulp sheet (manufactured by Lion Corporation, Lead Healthy Cooking Paper Double (product name), basis weight 40 g/m ² ) cut into 8 cm x 8 cm was placed on top of the SMS nonwoven fabric or moisture permeable film. .
1 g of three types of wet tension test solutions (surface tension at 25° C.: 35 mN/m, 55 mN/m and 72 mN/m) was injected into the center of the dry pulp sheet using a dropper. After the injection, an acrylic plate with a diameter of 60 mm was placed on top of the plate, a 2 kg weight was placed on top of the plate, and pressure was applied for 1 hour.
After one hour had passed, the weight was removed, and the extent of the liquid seeping out onto the filter paper was visually observed to determine the presence or absence of seeping out. Three sets of each level were evaluated, and the degree of seepage was evaluated based on the following criteria.
A: All three sheets have not oozed out.
B: Staining is observed on only one sheet.
C: Staining was observed on only two sheets.
D: Staining is observed on all three sheets.

As is clear from the results shown in Table 1, the absorbent articles obtained in each Example maintain the same performance as the absorbent articles obtained in each Comparative Example in terms of the amount of liquid returned inside the article when wet. It can be seen that the humidity is lower than the absorbent articles obtained in each comparative example.
In particular, as is clear from the comparison between Example 1 and Example 2, when triglycerides are included in the constituent fibers of the melt-blown nonwoven fabric used as the back sheet, the seepage prevention property against liquids with low surface tension is high. I know it will happen.

10 Absorbent article 11 Skin side sheet 12 Non-skin side sheet 13 Absorbent core 14 Opening

Claims (7)

It has an absorbent core, a skin-side sheet located closer to the skin than the absorbent core, and a non-skin-side sheet composed of one or more sheets located closer to the non-skin than the absorbent core. ,
All of the sheet materials constituting the non-skin side sheet are made of fiber sheets,
An absorbent article, wherein the absorbent core is provided with a slit-shaped opening passing through the thickness direction of the absorbent core. The absorbent article according to claim 1, wherein the total opening area of the slit-shaped openings in a plan view of the absorbent core is 5% or more and 30% or less of the apparent area of the absorbent core. . The sheet material constituting the non-skin side sheet has a nonwoven fabric,
The absorbent article according to claim 1 or 2, wherein the nonwoven fabric includes fibers containing a thermoplastic resin having fiber-forming ability and triglyceride. The triglyceride is
(a) a mixture of a triglyceride containing in one molecule at least a group derived from a fatty acid having 16 carbon atoms and a triglyceride containing at least a group in one molecule originating from a fatty acid having 18 carbon atoms, or (b) carbon The absorbent article according to claim 3, comprising a triglyceride containing in one molecule at least a group derived from a fatty acid having 16 atoms and a group derived from a fatty acid having 18 carbon atoms. Based on the total amount of groups derived from fatty acids contained in all the triglycerides contained in the fiber, the proportion of groups derived from fatty acids having 16 carbon atoms is 1% by mass or more and less than 55% by mass, and carbon The absorbent article according to claim 4, wherein the proportion of groups derived from a fatty acid having 18 atoms is 5% by mass or more and less than 75% by mass. The sheet material constituting the non-skin side sheet has a laminated structure of a plurality of nonwoven fabrics,
The laminated structure includes at least a spunbond layer and a meltblown layer,
The ratio of the mass of the spunbond layer to the mass of the nonwoven fabric is 50% by mass or more and 95% by mass or less,
The absorbent article according to any one of claims 1 to 5, wherein the ratio of the mass of the meltblown layer to the mass of the nonwoven fabric is 5% by mass or more and 50% by mass or less. The sheet material constituting the non-skin side sheet has a nonwoven fabric including a meltblown layer,
The absorbent article according to any one of claims 1 to 5, wherein the constituent fibers of the melt-blown nonwoven fabric have a fiber diameter of 0.1 μm or more and 10 μm or less.

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