JP7649166B2 - Absorbent articles - Google Patents

Description

The present invention relates to an absorbent article.

Conventionally, an antibacterial agent has been placed on the top sheet of an absorbent article to prevent skin rash. For example, Patent Document 1 describes an absorbent article having a top sheet and a liquid-permeable sheet placed in contact with the non-skin side of the top sheet, in which the top sheet and the liquid-permeable sheet contain an antibacterial agent. Benzalkonium chloride, etc., is used as the antibacterial agent.

Patent Document 2 describes a top sheet in an absorbent article that is made of a nonwoven fabric of composite fibers having a core and a sheath, and that a fine powder that has an anti-rough skin effect is kneaded only into the sheath, with part of the fine powder being exposed on the surface of the fiber. Zinc oxide or the like is used as the fine powder.

JP 2017-6505 A JP 2006-55187 A

In the absorbent article of Patent Document 1, the antibacterial agent applied to the top sheet is miscible with water, and so the antibacterial agent mixes with water when urinated, and the mixed antibacterial agent migrates to the absorbent core, which can reduce the amount of antibacterial agent contained in the top sheet. Since feces easily adhere to the top sheet, a top sheet with a reduced amount of antibacterial agent has a reduced antibacterial effect against feces. As a result, feces adhering to the top sheet is likely to cause skin rashes.

In Patent Document 2, antibacterial measures are taken for the top sheet, but no consideration is given to exerting antibacterial effects in the absorbent core. Therefore, in the absorbent article in this document, when urine is absorbed into the absorbent core, bacteria may grow in the absorbent core, causing a foul odor.

As described above, in the absorbent articles of Patent Documents 1 and 2, it was difficult to maintain the antibacterial effect for a long period of time.
Therefore, an object of the present invention is to provide an absorbent article that can overcome the above-mentioned drawbacks of the prior art.

The present invention provides a diaper absorbing material comprising an absorbent body and a top sheet disposed on the skin-facing side of the absorbent body,
The top sheet has an upper layer and a lower layer located on the non-skin facing side of the upper layer,
the top layer includes a first antimicrobial agent and the absorbent body includes a second antimicrobial agent;
The first antimicrobial agent is less soluble in water than the second antimicrobial agent, providing an absorbent article.

The present invention provides an absorbent article that can prevent skin rashes caused by feces and bacterial growth in the absorbent core for a long period of time.

FIG. 1 is a schematic diagram showing a widthwise cross section of an absorbent article according to one embodiment of the present invention.

The present invention will now be described based on preferred embodiments with reference to the drawings.
The absorbent article of the present invention generally has an elongated shape having a longitudinal direction corresponding to the direction extending from the wearer's abdominal side through the crotch portion to the dorsal side and a width direction perpendicular to the longitudinal direction. The absorbent article has a crotch portion disposed in the crotch portion of the wearer, and abdominal and dorsal portions extending in front and behind the crotch portion. The crotch portion has an excretory portion-facing portion that is disposed facing the excretory portion of the wearer when the absorbent article is worn, and the excretory portion-facing portion is usually located in the longitudinal center of the absorbent article or in the vicinity thereof.

Figure 1 shows one embodiment of the absorbent article of the present invention. The absorbent article 1 shown in Figure 1 has an absorbent body 3, a top sheet 2 arranged on the skin-facing side of the absorbent body 3, and a back sheet 4 arranged on the non-skin-facing side of the absorbent body 3.

The "skin-facing side" refers to the side of the absorbent article or its constituent parts (e.g., absorbent body) that faces the wearer's skin when the absorbent article is worn, and the "non-skin-facing side" refers to the side that faces away from the wearer's skin when the absorbent article is worn. Furthermore, "when worn" and "worn state" refer to the state in which the absorbent article is worn while maintaining the correct wearing position.

The top sheet 2 covers the skin-facing surface of the absorbent body 3. The top sheet 2 may cover only a portion of the skin-facing surface of the absorbent body 3, or may cover the entire skin-facing surface of the absorbent body 3.

As the top sheet 2, for example, a hydrophilic liquid-permeable sheet, a nonwoven fabric, a perforated film, etc. can be used. The skin-facing side of the top sheet 2 may have an uneven shape. For example, a plurality of scattered convex portions can be formed on the skin-facing side of the top sheet 2. Alternatively, ridges and grooves extending in one direction can be formed alternately on the skin-facing side of the top sheet 2. For such a purpose, the top sheet 2 can be formed using two sheets of nonwoven fabric.

The back sheet 4 covers the non-skin facing surface of the absorbent body 3. The back sheet 4 may cover only a portion of the non-skin facing surface of the absorbent body 3, or may cover the entire non-skin facing surface of the absorbent body 3.

The back sheet 4 may be, for example, a liquid-impermeable film or a spunbond, meltblown, or spunbond laminated nonwoven fabric that is poorly liquid-permeable. A liquid-impermeable film may be provided with a plurality of micropores to impart water vapor permeability to the film. To further improve the feel of the absorbent article against the skin, a sheet with a good texture, such as a nonwoven fabric, may be laminated on the outer surface of the back sheet 4.

The absorbent body 3 has an absorbent core 32 and a core wrap sheet 31 that covers the absorbent core 32. It is preferable that at least the skin-facing surface of the absorbent core 32 is covered with the core wrap sheet 31, and it is even more preferable that the entire surface, including the skin-facing surface and the non-skin-facing surface, is covered with the core wrap sheet.

The absorbent core 32 is composed of, for example, a stack of hydrophilic fibers such as cellulose, starting with pulp, a mixed stack of the hydrophilic fibers and an absorbent polymer, a pile of absorbent polymers, or a laminated structure in which an absorbent polymer is supported between two absorbent sheets.

The core wrap sheet 31 has an upper core wrap sheet 31a that covers the skin-facing side of the absorbent core 32, and a lower core wrap sheet 31b that covers the non-skin-facing side of the absorbent core 32. The upper core wrap sheet 31a and the lower core wrap sheet 31b may be integrated into a single sheet, or may be separate sheets.

The core wrap sheet 31 can be, for example, tissue paper made of hydrophilic fibers or liquid-permeable nonwoven fabric.

In addition to the above-mentioned top sheet 2, back sheet 4, and absorbent body 3, leakage prevention cuffs (not shown) extending along the longitudinal direction may be arranged on both sides along the longitudinal direction of the skin-facing side depending on the specific use of the absorbent article 1. The leakage prevention cuffs generally have a base end and a free end. The leakage prevention cuffs have a base end on the skin-facing side of the absorbent article 1 and stand up from the skin-facing side. The leakage prevention cuffs are made of a liquid-resistant or water-repellent material and are breathable. An elastic member made of rubber thread or the like may be arranged in a stretched state at or near the free end of the leakage prevention cuff. When the absorbent article 1 is worn, this elastic member contracts, causing the leakage prevention cuffs to stand up toward the wearer's body, effectively preventing liquid excreted on the top sheet 2 from leaking outward in the width direction of the absorbent article 1 along the top sheet 2.

The absorbent article 1 may further have an adhesive layer on the surface of the non-skin-facing side. The adhesive layer is used to attach the absorbent article 1 to underwear or another absorbent article when the absorbent article 1 is worn.

Examples of absorbent articles 1 having the above configuration include, but are not limited to, flat-type disposable diapers, pants-type disposable diapers, sanitary napkins, and light incontinence pads.

The absorbent article 1 of this embodiment contains two different types of antibacterial agents. The two types of antibacterial agents are distinguished by their different solubilities in water. In the following description, of the two antibacterial agents, the antibacterial agent with lower solubility in water will be referred to as the "first antibacterial agent," and the antibacterial agent with higher solubility in water will be referred to as the "second antibacterial agent." The first antibacterial agent and the second antibacterial agent are present in different locations in the absorbent article 1. The locations and types of each antibacterial agent will be described in detail below.

The first antibacterial agent is preferably contained in the top sheet 2. In particular, it is preferable that the top sheet 2 is composed of an upper layer 21 and a lower layer 22 located on the non-skin-facing side of the upper layer 21, and that the first antibacterial agent is contained in the upper layer 21. The upper layer 21 and the lower layer 22 may be adjacent to each other as shown in Figure 1, or one or more other layers may be interposed between the layers 21, 22.
The first antibacterial agent may be contained throughout the entire upper layer 21, or may be contained only in a portion of the upper layer 21. In particular, the first antibacterial agent is preferably contained at least in the portion of the upper layer 21 facing the excretory part. Moreover, the first antibacterial agent may be distributed in the upper layer 21 in a scattered manner, or in a plurality of stripes extending along the longitudinal direction.

On the other hand, the second antibacterial agent is preferably contained in the absorbent body 3. The second antibacterial agent may be contained throughout the entire absorbent body 3, or may be contained only in a portion of the absorbent body 3. In this embodiment, the absorbent body 3 has an absorbent core 32 and a core wrap sheet 31, and the second antibacterial agent may be contained in only one of the absorbent core 32 and the core wrap sheet 31, but it is preferable that the second antibacterial agent is contained in at least the core wrap sheet 31, and it is more preferable that the second antibacterial agent is contained in both the absorbent core 32 and the core wrap sheet 31.

By disposing the first antibacterial agent and the second antibacterial agent as described above, the first antibacterial agent exerts an antibacterial effect in the top sheet 2, and the second antibacterial agent exerts an antibacterial effect in the core wrap sheet 31 and the absorbent core 32. In detail, since the top sheet 2 contains the first antibacterial agent with relatively low solubility in water, even if urine excreted by the wearer comes into contact with the top sheet 2, the first antibacterial agent is unlikely to dissolve from the top sheet 2, and the first antibacterial agent can be prevented from migrating from the top sheet 2 to the absorbent core 32. Therefore, since the content of the first antibacterial agent in the top sheet 2 can be prevented from decreasing, the top sheet 2 can prevent skin rash caused by feces for a long period of time. On the other hand, since the absorbent body 3 contains the second antibacterial agent with relatively high solubility in water, when urine excreted by the wearer reaches the absorbent body 3, the second antibacterial agent dissolves from the absorbent body 3 into the urine and easily migrates into the absorbent core 32 together with the urine. In this way, the second antibacterial agent can be retained in the absorbent core 32 by using urination, so that the proliferation of bacteria caused by urine can be prevented for a long period of time in the absorbent core 32. As described above, according to the absorbent article 1 of this embodiment, it is possible to prevent skin rashes caused by feces and the proliferation of bacteria in the absorbent core for a long period of time.

In order to make the above effects more pronounced, it is preferable that the first antibacterial agent is present only in the top sheet 2, and that the first antibacterial agent is not present in other components of the absorbent article 1, including the absorbent body 3. On the other hand, it is preferable that the second antibacterial agent is present only in the core wrap sheet 31, and that the second antibacterial agent is not present in other components of the absorbent article 1, including the top sheet 2.

The solubility of each antibacterial agent in water can be compared based on the solubility measured by the following method.
<Method for measuring the solubility of antibacterial agents>
5 g of the antibacterial agent is added to 100 ml of water and stirred at 300 rpm for 30 minutes at room temperature (25° C.) Separately, the mass of the filter paper is measured, and the measured mass is regarded as the initial mass of the filter paper.
The stirred solution is filtered using the filter paper whose mass has been measured, and the filter paper is dried in a dryer at 40° C. for 2 hours. The mass of the dried filter paper is measured, and the measured mass is regarded as the dried mass of the filter paper. The solubility is then calculated using the following formula.
Solubility (g) = 5 (g) - {(mass of dried filter paper) (g) - (initial mass of filter paper) (g)}
A higher solubility calculated in this manner indicates a higher solubility in water, and a lower solubility indicates a lower solubility in water.

The difference in solubility between the first antibacterial agent and the second antibacterial agent is preferably 0.5 g/100 ml or more, more preferably 1 g/100 ml or more, and even more preferably 2 g/100 ml or more, from the viewpoint of making the effect of preventing skin rash caused by feces and bacterial growth in the absorbent core more pronounced over a long period of time. The upper limit of the difference in solubility between the first antibacterial agent and the second antibacterial agent can be, for example, 10 g/100 ml or less.

The solubility of the second antibacterial agent is preferably 1 g/100 ml to 10 g/100 ml, more preferably 2 g/100 ml to 8 g/100 ml, and even more preferably 4 g/100 ml to 6 g/100 ml, in order to more significantly prevent bacterial growth in the absorbent core for a long period of time.
From the viewpoint of making the effect of preventing skin rash caused by stool for a long period of time more remarkable, the solubility of the first antibacterial agent is preferably 0.01 g/100 ml or more and 0.5 g/100 ml or less, more preferably 0.03 g/100 ml or more and 0.3 g/100 ml or less, and even more preferably 0.05 g/100 ml or more and 0.2 g/100 ml or less.

The first antibacterial agent preferably contains a metal oxide. Metal oxides have low solubility in water, and therefore have the advantage that they are less likely to dissolve in urine even when they come into contact with urine, and therefore tend to remain on the top sheet 2. Examples of metal oxides include zinc oxide, silver oxide, aluminum oxide, titanium oxide, calcium oxide, magnesium oxide, and the like. These metal oxides may be used alone or in combination of two or more. Of these, it is preferable that the first antibacterial agent contains zinc oxide, as this has a higher antibacterial property.

When the first antibacterial agent is a metal oxide, its particle size is appropriately determined from the viewpoint of the thickness of the fibers constituting the upper layer 21 and the ease of kneading the metal oxide into the fibers. In general, the average particle size of the metal oxide is 1.5 μm or more and 7 μm or less, expressed as a volume cumulative particle size _D50 at a cumulative volume of 50% by volume according to a laser diffraction scattering type particle size distribution measurement method.

It is also preferable that the first antibacterial agent is soluble in a solution containing protein. Since stool contains protein, by making the first antibacterial agent soluble in a solution containing protein, the first antibacterial agent can be easily transferred to the stool adhering to the top sheet 2, and skin rash can be more effectively prevented. As used herein, "protein" includes, for example, digestive enzymes contained in stool.
Whether or not the first antibacterial agent is soluble in a solution containing a protein can be confirmed by comparing the solubility of the first antibacterial agent in a solution in which bovine serum albumin (BSA) is dissolved in phosphate buffered saline (PBS) as a model protein (hereinafter also referred to as "standard solubility") with the solubility of the first antibacterial agent in PBS in which BSA is not dissolved (hereinafter also referred to as "reference solubility"). Specifically, when the standard solubility is greater than or equal to the reference solubility, it can be determined that the first antibacterial agent is soluble in a solution containing a protein. The method for measuring solubility is as described above.

The first antibacterial agent is preferably kneaded into the fibers constituting the upper layer 21. This makes it difficult for the first antibacterial agent to be detached from the upper layer 21 even if it comes into contact with urine. When the first antibacterial agent is kneaded into the fibers constituting the upper layer 21, the entire first antibacterial agent may be present inside the fibers, or a part of the first antibacterial agent may be exposed on the surface of the fibers. When the fibers constituting the upper layer 21 are core-sheath type composite fibers, the first antibacterial agent may be contained in only one of the core and sheath of the fibers, or in both the core and sheath.

The reason why the top sheet 2 has a two-layer structure of an upper layer 21 and a lower layer 22 and contains the first antibacterial agent in the upper layer 21 is that the upper layer 21 is in direct contact with the wearer's skin, and thus containing the first antibacterial agent in the upper layer 21 can effectively suppress skin rash caused by feces. Therefore, as long as the upper layer 21 contains the first antibacterial agent, the lower layer 22 may contain the first antibacterial agent. In other words, the entire top sheet 2 may contain the first antibacterial agent. However, the first antibacterial agent contained in the lower layer 22 does not contribute significantly to suppressing skin rash, and the amount of the antibacterial agent used is larger than when the first antibacterial agent is contained only in the upper layer 21, which is uneconomical. In addition, by providing a layer that does not contain an antibacterial agent between the upper layer 21 and the core wrap sheet 31, urine once absorbed in the absorbent core 32 can be prevented from returning to the top sheet 2 side. Therefore, in the top sheet 2, it is preferable that only the upper layer 21 contains the first antibacterial agent, and the lower layer 22 is substantially free of the first antibacterial agent. The term "substantially free" includes both cases where the lower layer 22 does not contain the first antibacterial agent at all, and cases where a trace amount of the first antibacterial agent is inevitably mixed into the lower layer 22. For the same reason, it is preferable that the lower layer 22 is also substantially free of the second antibacterial agent. In other words, it is preferable that the lower layer 22 is substantially free of an antibacterial agent. The lower layer 22 being substantially free of an antibacterial agent means that the mass of the antibacterial agent contained in the lower layer 22 is less than 0.1% by mass, preferably less than 0.05% by mass, relative to the mass of the lower layer 22.

When the top sheet 2 has a two-layer structure consisting of an upper layer 21 and a lower layer 22, the top sheet 2 may have the upper layer 21 and the lower layer 22 integrated into a single sheet, or may have a structure in which two sheets are simply stacked one on top of the other.

The top sheet 2 is preferably made of a fiber sheet such as a nonwoven fabric. The content of the first antibacterial agent in the top sheet 2 is preferably less than 3.0% by mass, more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less, relative to the mass of the upper layer 21, from the viewpoint of improving the ejection performance of the spinning nozzle when spinning the constituent fibers of the top sheet 2, and from the viewpoint of increasing the strength of the spun fibers. The lower limit of the mass of the first antibacterial agent relative to the mass of the fibers contained in the upper layer 21 can be 0.3% by mass.

The content of the first antibacterial agent can be measured by the following method.
<Method of measuring content of first antibacterial agent>
1 g of the upper layer 21 of the top sheet 2 of the diaper 1 is weighed out, cut into pieces as small as possible, and placed in a 300 ml beaker. 200 ml of ion-exchanged water is added to the beaker and stirred with a magnetic stirrer so that the fibers are completely in contact with the water. 3 ml of concentrated hydrochloric acid (about 10 M) is gradually added while stirring the liquid, and the liquid is further stirred for 1 hour to elute the first antibacterial agent present on the surface of the fibers constituting the upper layer 21. Next, 6 ml of 5.1 M sodium hydroxide aqueous solution is added to neutralize the liquid, and then 10 ml of a buffer solution of pH 10.7 (containing 54.7 ml of 28% by mass _NH3 aqueous solution and 0.535 g of _NH4Cl dissolved in ion-exchanged water) is added to finely adjust the pH.
Next, Eriochrome Black T reagent (0.125 g of Eriochrome Black T powder and 1.125 g of hydroxylamine hydrochloride dissolved in 25 ml of absolute ethanol) is added as an indicator to turn the liquid pale pink. Titration is performed using 0.0002 M EDTA.2Na as a titrant, and the amount (ml) of the titrant added when the liquid changes color from pink to pale blue to green is defined as the titration value A. Then, the mass of the first antibacterial agent is calculated using the following formula. In the formula, "5,000,000" means the volume (ml) of the titrant per mol.
Mass (g) of first antibacterial agent = titration value A x mass per 1 mol of first antibacterial agent / 5,000,000
The mass of the antibacterial agent calculated as described above is the mass of the antibacterial agent contained in 1 g of the upper layer 21. Therefore, the value obtained by multiplying the calculated mass of the antibacterial agent by 100 is the content ratio of the first antibacterial agent.

When the first antibacterial agent is a metal oxide, it is preferable that the lower layer 22 of the top sheet 2 contains a metal oxide different from the metal oxide contained in the first antibacterial agent. By doing so, for example, it is possible to impart an antibacterial effect to the upper layer 21 and to impart an effect different from that of the upper layer 21 to the lower layer 22, for example, an effect of making the top sheet 2 appear white. When the first antibacterial agent is, for example, zinc oxide, the "metal oxide different from the metal oxide contained in the first antibacterial agent" means that the antibacterial agent contained in the lower layer 22 may be any one of titanium oxide, calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, calcium oxide, aluminum oxide, mica, glass powder, shirasu balloon, zeolite, and silicate clay. Titanium oxide is present, for example, by being kneaded into the fibers constituting the lower layer 22 as a white pigment.

From the viewpoint of further enhancing the antibacterial effect of the first antibacterial agent, the basis weight of the first antibacterial agent is preferably 0.03 g/ ^m2 or more and 0.6 g/ ^m2 or less, more preferably 0.05 g/ ^m2 or more and 0.3 g/m2 or ^less , and even more preferably 0.07 g/ ^m2 or more and 0.1 g/ ^m2 or less.

The basis weight of the first antimicrobial agent can be measured by the following method.
<Method of measuring basis weight of first antibacterial agent>
A piece of 300 ^mm2 or more is cut from the top sheet. If the area of the piece is less than 300 ^mm2 , pieces are cut from multiple locations so that the total area is 300 ^mm2 or more. The piece is cut so as to include both the upper and lower layers.
Next, the slice is subjected to a multi-stage solvent extraction method using a non-polar solvent to a polar solvent, and the antibacterial agent present in the slice is separated to obtain a solution containing a single composition. The obtained solution is dried and solidified, and the chemical structure of the antibacterial agent is identified by a combination of ¹ H-NMR (nuclear magnetic resonance), IR (infrared spectroscopy), LC (liquid chromatography), GC (gas chromatography), MS (mass spectrometry), GPC (gel permeation chromatography), fluorescent X-rays, etc. In addition, a calibration curve is created by a known analytical means such as GC and LC using an antibacterial agent having a specified chemical structure as a standard substance, and the antibacterial agent in the slice is quantified. Based on this quantification result, the mass of the antibacterial agent in the slice is determined. When multiple types of antibacterial agents are present in the slice, the sum of the masses of the various antibacterial agents is determined, and the sum is regarded as the mass of the antibacterial agent in the slice. Then, the mass of the antibacterial agent in the slice is divided by the area of the slice to calculate the basis weight of the antibacterial agent.

Next, the second antibacterial agent will be described. There is no particular restriction on the type of the second antibacterial agent as long as its solubility in water is higher than that of the first antibacterial agent. In particular, it is preferable to use a cationic surfactant as the second antibacterial agent. Since cationic surfactants are easily soluble in water, the second antibacterial agent can be quickly dissolved in urine by contacting with urine and smoothly transferred to the absorbent core 32. Examples of cationic surfactants include tetraalkylammonium salts, trialkylbenzylammonium salts such as benzalkonium chloride, monoalkyltrimethylammonium salts, dialkyldimethylammonium salts, trialkylmonomethylammonium salts, and monoalkyldimethylbenzylammonium salts. These cationic surfactants can be used alone or in combination of two or more.
Examples of monoalkyldimethylbenzylammonium salts include benzalkonium cetyl phosphate, alkylbenzyldimethylammonium chloride, etc. Among these, it is preferable to use benzalkonium cetyl phosphate.

The second antibacterial agent preferably contains a plant extract. The emollient effect of the plant extract more effectively suppresses skin rashes on the wearer. Examples of plant extracts include witch hazel extract, oat extract, seaweed (hibamata), yuzu extract, sanguisorba officinalis extract, asarum extract, aloe extract, phellodendron bark extract, horsetail extract, chamomile extract, eucalyptus extract, peach leaf extract, and green tea extract.

From the viewpoint of achieving both the antibacterial effect and the effect of preventing stickiness of a liquid in which the antibacterial agent is dissolved, the basis weight of the second antibacterial agent in the absorbent body 3 is from 1 mg/ ^m2 to 80 mg/ ^m2 , preferably from 2.5 mg/ ^m2 to 80 mg/ ^m2 , more preferably from 20 mg/ ^m2 to 80 mg/ ^m2 , and even more preferably from 30 mg/ ^m2 to 50 mg/ ^m2 .

The basis weight of the second antimicrobial agent can be measured by the following method.
<Method of measuring basis weight of second antibacterial agent>
A piece of 300 ^mm2 or more is cut out from the absorbent body. If the area of the piece is less than 300 ^mm2 , cut out pieces from multiple locations so that the total area is 300 ^mm2 or more. The piece is cut so as to include both the absorbent core and the core wrap sheet.
Next, the antibacterial agent in the slice cut from the absorbent is quantified using the same method as in the <Method for Measuring Basis Weight of First Antibacterial Agent>. The mass of the antibacterial agent in the slice is calculated based on the quantification result. If multiple types of antibacterial agents are present in the slice, the sum of the masses of the various antibacterial agents is calculated, and this sum is the mass of the antibacterial agent in the slice. The mass of the antibacterial agent in the slice is then divided by the area of the slice to calculate the basis weight of the antibacterial agent.

From the viewpoint of more effectively preventing bacterial growth in the absorbent core 32, the second antibacterial agent is preferably contained in the core wrap sheet 31 of the absorbent body 3. The second antibacterial agent may be contained throughout the entire core wrap sheet 31, or may be contained only in a portion of the core wrap sheet 31. In this embodiment, the core wrap sheet 31 has an upper core wrap sheet 31a and a lower core wrap sheet 31b as shown in FIG. 1. The second antibacterial agent may be contained in only one of the upper core wrap sheet 31a and the lower core wrap sheet 31b, but it is preferable that the second antibacterial agent is contained in at least the upper core wrap sheet 31a, and more preferable that the second antibacterial agent is contained in both the upper core wrap sheet 31a and the lower core wrap sheet 31b.

From the same viewpoint, it is also preferable that the second antibacterial agent is contained at a uniform concentration throughout the absorbent body 3. In other words, it is preferable that the second antibacterial agent is contained and dispersed homogeneously throughout the absorbent body 3.

The second antibacterial agent may be contained in a non-uniformly dispersed manner throughout the absorbent body 3. Specifically, the second antibacterial agent may be contained in a greater amount on the ventral side of the absorbent body 3 than on the dorsal side of the absorbent body 3, or vice versa. In general, excretory parts such as the urethral opening of a wearer are present on the ventral side of the wearer, so that the second antibacterial agent is more likely to dissolve from the absorbent body 3 into urine, and from the viewpoint of more effectively preventing bacterial proliferation in the absorbent core 32, it is preferable that the second antibacterial agent be contained in a greater amount on the ventral side of the absorbent body 3 than on the dorsal side of the absorbent body 3.

In this embodiment, it is preferable that the core wrap sheet 31 and the absorbent core 32 are joined via a first adhesive 5a and a third adhesive 5b. In particular, it is preferable that the skin-facing surface of the absorbent core 32 and the non-skin-facing surface of the upper core wrap sheet 31a are joined by the first adhesive 5a. It is also preferable that the non-skin-facing surface of the absorbent core 32 and the skin-facing surface of the lower core wrap sheet 31b are joined by the third adhesive 5b.

It is also preferable that the top sheet 2 and the core wrap sheet 31 are joined via a second adhesive 5c. In particular, it is preferable that the non-skin-facing surface of the lower layer 22 of the top sheet 2 and the skin-facing surface of the upper core wrap sheet 31a are joined by the second adhesive 5c.

Focusing on the upper core wrap sheet 31a, the first adhesive 5a and the second adhesive 5c are applied to the non-skin facing surface and the skin facing surface of the upper core wrap sheet 31a, respectively. In this case, it is preferable that the basis weight of the first adhesive 5a is smaller than the basis weight of the second adhesive 5c. By doing so, when the second antibacterial agent contained in the upper core wrap sheet 31a comes into contact with urine and dissolves from the upper core wrap sheet 31a, it is easy to migrate to the absorbent core 32 together with the urine, so that the proliferation of bacteria in the absorbent core 32 can be more effectively prevented. From the viewpoint of making this effect more prominent, the ratio (A2/A1) of the basis weight A2 of the first adhesive 5a on the non-skin facing surface of the upper core wrap sheet 31a to the basis weight A1 of the second adhesive 5c on the skin facing surface of the upper core wrap sheet 31a is preferably 1.0 or less, more preferably 0.8 or less, and even more preferably 0.6 or less. The lower limit of A2/A1 can be set to 0.1.

From the viewpoint of more effectively preventing the proliferation of bacteria within the absorbent core 32, the basis weight of the first adhesive is preferably 1 g/m2 or ^more and 8 g/ ^m2 or less, more preferably 1.5 g/m2 or ^more and 6 g/m2 or ^less , and even more preferably 2 g/ ^m2 or more and 5 g/m2 or ^less .
From the same viewpoint, the basis weight of the second adhesive is preferably 1.5 g/m2 or ^more and 10 g/m2 or ^less , more preferably 2 g/ ^m2 or more and 8 g/m2 or ^less , and even more preferably 3 g/m2 or ^more and 6 g/ ^m2 or less.

The basis weight of the adhesive can be measured by the following method.
<Method for measuring adhesive basis weight>
Hereinafter, a method for measuring the basis weight of an adhesive will be described using the method for measuring the basis weight of the first adhesive as an example. The basis weight of the second adhesive can also be measured in the same manner.
First, the coating area of the first adhesive is measured. Specifically, the top sheet of the absorbent article is carefully peeled off from the upper core wrap sheet. At this time, it is preferable that as little of the first adhesive remains on the top sheet as possible. Then, a printed toner is applied to the skin-facing surface of the upper core wrap sheet, i.e., the surface on which the first adhesive is coated, and is allowed to adhere to the first adhesive. In this way, the coating state of the first adhesive is made visible by the toner, the skin-facing surface of the upper core wrap sheet is read by a scanner, and the coating area of the first adhesive is measured by area calculation software.
Next, the amount of the first adhesive applied is measured. Specifically, the upper core wrap sheet, whose application area of the first adhesive has been measured, is carefully peeled off from the absorbent core. At this time, it is preferable to remove the second adhesive from the non-skin-facing surface of the upper core wrap sheet. When the core wrap sheet is made of one sheet, the portion of the core wrap sheet read by the scanner is cut out, and the cut-out portion is used as the upper core wrap sheet. Then, the skin-facing surface of the upper core wrap sheet is immersed in toluene and then dried. When the second adhesive remains on the non-skin-facing surface of the upper core wrap sheet, it is preferable to immerse the upper core wrap sheet in toluene so that the toluene does not reach the non-skin-facing surface of the upper core wrap sheet. Then, the application amount of the first adhesive can be calculated by subtracting the mass of the upper core wrap sheet after immersing in toluene and drying from the mass of the upper core wrap sheet before immersing in toluene.
Then, the basis weight of the first adhesive can be obtained by dividing the applied amount of the first adhesive by the applied area.

In this embodiment, it is preferable that no adhesive is applied to the upper layer 21 of the top sheet 2. The upper layer 21 contains a first antibacterial agent, and the fact that no adhesive is applied to the upper layer 21 means that the first antibacterial agent is not in contact with the adhesive. This makes it easier for the first antibacterial agent contained in the upper layer 21 to transfer to feces attached to the top sheet 2, and skin rash can be more effectively prevented. From this perspective, it is preferable that the upper layer 21 is composed of a nonwoven fabric manufactured without using an adhesive, such as an air-through nonwoven fabric, a spunbond nonwoven fabric, or a spunlace nonwoven fabric. The upper layer 21 and the lower layer 22 of the top sheet 2 are preferably joined by heat fusion.

Either or both of the top sheet 2 and the absorbent 3 may contain a plant extract. The emollient effect of the plant extract makes it possible to effectively suppress skin rashes of the wearer. As the plant extract, the same one that can be contained in the second antibacterial agent can be used. Either or both of the upper layer 21 and the lower layer 22 of the top sheet 2 may contain a plant extract. Either or both of the absorbent core 32 and the core wrap sheet 31 of the absorbent 3 may contain a plant extract.

Although the present invention has been described based on the embodiment, the present invention is not limited to the embodiment and can be modified as appropriate.
For example, in the above embodiment, the absorbent article 1 contains two types of antibacterial agents, a first antibacterial agent and a second antibacterial agent, but in addition to this, the absorbent article of the present invention may contain a third antibacterial agent having a different solubility in water from the first antibacterial agent and the second antibacterial agent.

In relation to the above-mentioned embodiment, the present invention further discloses the following absorbent article.
＜1＞
The device comprises an absorbent body and a top sheet disposed on the skin-facing side of the absorbent body,
The top sheet has an upper layer and a lower layer located on the non-skin-facing side of the upper layer,
the top layer includes a first antimicrobial agent and the absorbent body includes a second antimicrobial agent;
An absorbent article, wherein the first antimicrobial agent is less soluble in water than the second antimicrobial agent.
＜2＞
The absorbent article according to <1> above, wherein the difference in solubility between the first antibacterial agent and the second antibacterial agent is preferably 0.5 g/100 ml or more, more preferably 1 g/100 ml or more, and even more preferably 2 g/100 ml or more.
＜3＞
The absorbent article according to <1> or <2>, wherein the solubility of the first antibacterial agent is preferably 0.01 g/100 ml or more and 0.5 g/100 ml or less, more preferably 0.03 g/100 ml or more and 0.3 g/100 ml or less, and even more preferably 0.05 g/100 ml or more and 0.2 g/100 ml or less.
＜4＞
The absorbent article described in any one of <1> to <3> above, wherein the solubility of the second antibacterial agent is preferably 1 g/100 ml or more and 10 g/100 ml or less, more preferably 2 g/100 ml or more and 8 g/100 ml or less, and even more preferably 4 g/100 ml or more and 6 g/100 ml or less.
＜5＞
The absorbent article according to any one of <1> to <4>, wherein the lower layer is substantially free of an antibacterial agent.
＜6＞
The absorbent article according to any one of <1> to <5>, wherein the first antibacterial agent is not in contact with the adhesive.
＜７＞
The absorbent body has an absorbent core and a core wrap sheet that covers the absorbent core,
An absorbent article described in any one of <1> to <6>, wherein a second antibacterial agent is contained in either the absorbent core or the core wrap sheet, preferably in both the absorbent core and the core wrap sheet.
＜8＞
The core wrap sheet has an upper core wrap sheet that covers the skin-facing side of the absorbent core,
The skin-facing surface of the absorbent core and the non-skin-facing surface of the upper core wrap sheet are joined by a first adhesive,
The non-skin facing surface of the top sheet and the skin facing surface of the upper core wrap sheet are joined by a second adhesive,
The absorbent article according to <7> above, wherein the basis weight of the first adhesive is smaller than the basis weight of the second adhesive.
＜9＞
The absorbent article described in <8> above, wherein the ratio of the basis weight of the first adhesive to the basis weight of the second adhesive is preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.6 or less, and also preferably 0.1 or more.
＜10＞
The absorbent article according to <8> or ^<9> , wherein the basis weight of the first adhesive is preferably 1 g/m2 or ^more and 8 g/m2 or less, more preferably 1.5 g/ ^m2 or ^more and 6 g/m2 or less, and even more preferably ² g/ ^m2 or more and 5 g/m2 or less.
<11>
The absorbent article according to any ^one of <8> to <10>, wherein the basis weight of the second adhesive is preferably 1.5 g/ ^m2 or ^more and 10 g/m2 or ^less , more preferably 2 g/m2 or more and 8 g/m2 or ^less , and even more preferably 3 g/ ^m2 or more and 6 g/m2 or less.
＜12＞
The absorbent article has a crotch portion disposed in the crotch area of a wearer, and a ventral side portion and a dorsal side portion extending in front and behind the crotch portion,
The absorbent article according to any one of <1> to <11>, wherein the second antibacterial agent is contained at a uniform concentration throughout the absorbent body.
＜13＞
The absorbent article has a crotch portion disposed in the crotch area of a wearer, and a ventral side portion and a dorsal side portion extending in front and behind the crotch portion,
The absorbent article according to any one of <1> to <11> , wherein the second antibacterial agent is contained in a larger amount on the ventral side of the absorbent body than on the dorsal side of the absorbent body.
＜14＞
The absorbent article according to any one of <1> to <13>, wherein the first antibacterial agent contains a metal oxide.
＜15＞
The absorbent article according to <14>, wherein the metal oxide is zinc oxide.
＜16＞
The absorbent article according to <14> or <15>, wherein the lower layer contains a metal oxide different from the metal oxide contained in the upper layer.
＜１７＞
The absorbent article according to <16>, wherein the metal oxide different from the metal oxide is selected from titanium oxide, calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, calcium oxide, aluminum oxide, mica, glass powder, shirasu balloon, zeolite, and silicate clay.
＜18＞
The content of the first antibacterial agent is less than 3.0% by mass, preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and also preferably 0.3% by mass or more, relative to the mass of the upper layer. The absorbent article according to any one of <1> to <17>.
＜19＞
The absorbent article according to any one of <1> to <18>, wherein the first antibacterial agent is soluble in a solution containing a protein.
＜20＞
The absorbent article according to any one of <1> to <19>, wherein the basis weight of the second antibacterial agent is 1 mg/ ^m2 or ^more and 80 mg/m2 ^{or less} , preferably 2.5 mg/ ^m2 or more and 80 mg/ ^m2 or less, more preferably 20 mg/ ^m2 or more and 80 mg/m2 or less, and even more preferably 30 mg/m2 or more and 50 mg/ ^m2 or less.
＜21＞
The absorbent article according to any one of <1> to <20>, wherein the second antibacterial agent is a cationic surfactant.
＜22＞
The absorbent article according to any one of <1> to <21>, wherein the top sheet or the absorbent body contains a plant extract.

Reference Signs List 1 Absorbent article 2 Top sheet 3 Absorbent body 31 Core wrap sheet 32 Absorbent core 4 Back sheet 5a, 5b, 5c Adhesive

Claims (9)

An absorbent article comprising an absorbent body and a top sheet disposed on a skin-facing side of the absorbent body,
The top sheet has an upper layer and a lower layer located on the non-skin facing side of the upper layer,
The absorbent body has an absorbent core and a core wrap sheet that covers the absorbent core,
The core wrap sheet has an upper core wrap sheet that covers the skin-facing side of the absorbent core,
the top layer includes a first antimicrobial agent and the upper core wrap sheet includes a second antimicrobial agent;
the first antimicrobial agent is present only in the top layer and not in other components of the absorbent article;
the second antimicrobial agent is present only in the core wrap sheet and not in other components of the absorbent article;
the underlayer being substantially free of antimicrobial agents;
the first antimicrobial agent is less soluble in water than the second antimicrobial agent;
the difference in solubility between the first antibacterial agent and the second antibacterial agent is 0.5 g/100 ml or more and 10 g/100 ml or less;
the solubility of the first antibacterial agent is 0.01 g/100 ml or more and 0.5 g/100 ml or less;
the solubility of the second antibacterial agent is 1 g/100 ml or more and 10 g/100 ml or less;
The skin-facing surface of the absorbent core and the non-skin-facing surface of the upper core wrap sheet are joined by a first adhesive,
The non-skin facing surface of the top sheet and the skin facing surface of the upper core wrap sheet are joined by a second adhesive,
a ratio of the basis weight of the first adhesive to the basis weight of the second adhesive is 0.1 or more and 0.8 or less;
The basis weight of the first adhesive is 1 g/m2 or ^more and 8 g/ ^m2 or less,
An absorbent article , wherein the second adhesive has a basis weight of 1.5 g/m2 or ^more and 10 g/m2 ^or less. The absorbent article of claim 1 , wherein the first antimicrobial agent is not in contact with the adhesive. The absorbent article has a crotch portion disposed in the crotch area of a wearer, and a ventral side portion and a dorsal side portion extending in front and behind the crotch portion,
The absorbent article according to claim 1 or 2 , wherein the second antibacterial agent is contained at a uniform concentration throughout the absorbent body, or is contained in a greater amount on the ventral side of the absorbent body than on the dorsal side of the absorbent body. The absorbent article of claim 1 , wherein the first antimicrobial agent comprises a metal oxide. 5. The absorbent article according to claim 1, wherein the content of the first antimicrobial agent is less than 3.0% by weight based on the weight of the upper layer. The absorbent article according to claim 1 , wherein the first antimicrobial agent is soluble in a solution containing a protein. 7. The absorbent article of claim 1, wherein the second antimicrobial agent is a cationic surfactant. The absorbent article according to claim 1 , wherein the topsheet or the absorbent body comprises a plant extract. The absorbent article of claim 1 , wherein the first antimicrobial agent comprises zinc oxide.

Images