JP7595616B2 - Absorbent articles - Google Patents

Description

The present invention relates to absorbent articles intended to absorb at least urine, such as incontinence pads, disposable diapers, and sanitary napkins.

Absorbent articles such as incontinence pads, disposable diapers, and sanitary napkins are used to absorb and retain excrement such as urine, feces, and menstrual blood discharged from the wearer. For this reason, absorbent articles are required to reduce the odor of excrement.

One method for reducing the odor of excrement in absorbent articles is the adsorption method using a physically adsorbent deodorant such as activated carbon. For example, Patent Document 1 discloses a composition in the form of bound particles, which is an agglomerated mixture of a deodorant made of black carbon particles, white particles selected from the group consisting of white deodorants and white masking substances, and a water-soluble or water-dispersible binder substance. The composition of Patent Document 1 is used as a deodorant for absorbent articles. This composition not only adsorbs malodorous molecules, but also makes the color of the black carbon particles less noticeable.

Patent Document 2 discloses an absorbent article having an absorbent body, the absorbent body having an absorbent core containing a water-absorbent polymer, an inner sheet arranged on the skin-facing side of the absorbent core, and an outer sheet arranged on the skin-facing side of the inner sheet. In the absorbent article of Patent Document 2, the inner sheet is colored gray by carrying activated carbon particles, the outer sheet is colored gray, and further, the L* value of the outer sheet in the L*a*b* color system is larger than the L* value of the inner sheet. Such an absorbent article can suppress the odor of urine and make the color of urine less noticeable.

Special Publication No. 5-503452 JP 2014-68681 A

In absorbent articles using the composition of Patent Document 1, although the white particles can make the color of the black carbon particles less noticeable, the color of the urine stands out due to the visual contrast with the white color, and this can cause discomfort to the user, such as a lack of cleanliness.

In addition, although the absorbent article in Patent Document 2 can make the color of urine less noticeable, it requires inner and outer sheets that are colored in specific colors, which creates a problem of structural constraints on the absorbent article.

The present invention was made in consideration of these problems, and aims to provide an absorbent article that is less likely to cause structural constraints, suppresses the urine odor, and makes the color of urine less noticeable.

As a result of intensive research conducted by the inventors to achieve the above object, they discovered that an adsorbent having an L* value of 10 or more in the L*a*b* color system and having pores and micropores of a specific pore size each with a specific volume or more can suppress the odor of urine and make the color of urine less noticeable. The present invention was completed based on this finding, and includes the following aspects.

(Aspect 1)
One aspect of the present invention (Aspect 1) is an absorbent article including an adsorbent that adsorbs urine odor and color,
The adsorbent has an L* value of 10 or more in the L*a*b* color system,
The absorbent article is characterized in that it has pores having a pore size of 1.5 to 2.0 nm in a volume of 0.006 mL/g or more, and micropores having a pore size of 0.3 to 0.8 nm in a volume of 0.050 mL/g or more.

The absorbent article of this embodiment 1 includes an adsorbent that adsorbs the odor and color of urine. This adsorbent can adsorb and hold urine pigment components (e.g., urobilin, etc.) in pores with a pore size of 1.5 to 2.0 nm. The pigment components held in the pores are surrounded and hidden by non-pore portions that have an L* value of 10 or more (gray to white) in the L*a*b* color system, making them difficult to see from the outside. The adsorbent has pores with a volume of 0.006 mL/g or more, so it can adsorb and hold a sufficient amount of pigment components.

Furthermore, this adsorbent is capable of adsorbing and retaining odorous components that cause urine odor in micropores with a pore size of 0.3 to 0.8 nm. The adsorbent has micropores with a volume of 0.050 mL/g or more, so it can adsorb and retain a sufficient amount of odorous components.

As a result, this adsorbent can suppress the odor of urine and make the color of urine less noticeable without requiring any other components other than the adsorbent (e.g., a concealing sheet or masking material, etc.).

Therefore, the absorbent article of this embodiment 1, which contains such an adsorbent, is less likely to have structural constraints, and is able to suppress the odor of urine and make the color of urine less noticeable. Furthermore, since being "white" is highly effective in creating a sense of cleanliness, such absorbent articles have the advantage of giving the user a positive impression of cleanliness in that they are white before use and remain white after use.

(Aspect 2)
In another aspect (aspect 2) of the present invention, in the absorbent article according to aspect 1, the adsorbent is made of a plurality of particles having a particle size of 500 μm or less.

In this embodiment, the adsorbent is composed of multiple particles with a particle size of 500 μm or less. This allows the absorbent article in this embodiment to have a large surface area of the adsorbent that can come into contact with urine, and to adsorb the odor and color of urine at a superior adsorption rate.

(Aspect 3)
In yet another aspect (Aspect 3) of the present invention, in the absorbent article of Aspect 1 or 2, the adsorbent comprises at least one porous material selected from the group consisting of activated carbon, silica gel, activated alumina, activated clay, synthetic zeolite, and synthetic polymers.

The above-mentioned porous material has the advantage that it can stably exert an adsorption effect and that the pore size of the pores and micropores can be easily controlled. Therefore, the absorbent article of this embodiment 3 can more reliably adsorb the odor and color of urine.

(Aspect 4)
In yet another aspect (Aspect 4) of the present invention, in the absorbent article of Aspect 3, the adsorbent is characterized in that the porous material is covered with at least one white inorganic material selected from titanium oxide, calcium carbonate, zinc oxide, barium sulfate, magnesium oxide, kaolin, and talc.

In this embodiment 4, the adsorbent is composed of the porous material and the white inorganic material that covers the porous material. The white inorganic material has excellent concealing power, so it can make the colorant components held in the pores of the adsorbent (i.e., the pores of the porous material) less visible from the outside. This makes the absorbent article of this embodiment 4 even less noticeable in color of urine. Furthermore, such an absorbent article also has the advantage of giving the user an even more positive impression of cleanliness.

(Aspect 5)
In still another aspect (aspect 5) of the present invention, in the absorbent article of aspect 4, the white-colored inorganic substance is a plurality of particles.

In this embodiment, the white inorganic material covering the porous material is a plurality of particles. This allows the adsorbent to adsorb and retain odorous components and colorant components in the pores and micropores of the porous material through the gaps between the particles of the white inorganic material. In other words, the adsorbent can make the colorant components adsorbed and retained in the pores of the porous material less visible from the outside without inhibiting the adsorption of odorous components and colorant components. Therefore, the absorbent article of this embodiment can more reliably suppress the odor of urine while making the color of urine even less noticeable.

(Aspect 6)
In yet another aspect (aspect 6) of the present invention, in the absorbent article of any of aspects 1 to 5 above, the absorbent article includes an absorbent body, and the adsorbent is disposed on at least one of the surface and the interior of the absorbent body.

In the absorbent article of this embodiment 6, the adsorbent is positioned in a position that is likely to come into contact with urine, so the adsorbent can more reliably suppress the urine odor and make the urine color less noticeable.

(Aspect 7)
In yet another aspect (aspect 7) of the present invention, in the absorbent article of aspect 6, the absorbent body includes an absorbent core containing a superabsorbent polymer, and the adsorbent is arranged in contact with the superabsorbent polymer.

In the absorbent article of this embodiment 7, the adsorbent is positioned in a position that is more likely to come into contact with urine, so the adsorbent can more reliably suppress the urine odor and make the urine color less noticeable.

(Aspect 8)
In yet another aspect (Aspect 8) of the present invention, in the absorbent article of any one of Aspects 1 to 7 above, the adsorbent is contained in an amount of 0.1 mass % or more relative to the total mass of the absorbent article.

The absorbent article of this embodiment 8 contains the above-mentioned adsorbent in a predetermined amount or more, so the adsorbent can more reliably suppress the urine odor and make the urine color less noticeable.

(Aspect 9)
Yet another aspect (Aspect 9) of the present invention is a method for treating urine, comprising contacting urine with an adsorbent that adsorbs urine odor and color, the method comprising the steps of:
The adsorbent has an L* value of 10 or more in the L*a*b* color system,
The above treatment method is characterized in that the porous medium has pores with a pore size of 1.5 to 2.0 nm in a volume of 0.006 mL/g or more, and micropores with a pore size of 0.3 to 0.8 nm in a volume of 0.050 mL/g or more.

The urine treatment method of this embodiment 9 includes contacting urine with an adsorbent that adsorbs the odor and color of urine. As described above, this adsorbent can suppress the odor of urine and make the color of urine less noticeable without requiring any other components.

Therefore, the urine treatment method of this embodiment 9 using such an adsorbent is less likely to cause structural constraints, and can suppress the urine odor and make the urine color less noticeable, making it applicable to a wide range of applications that require urine treatment, such as absorbent articles.

The present invention provides an absorbent article that is less likely to cause structural constraints, suppresses the odor of urine, and makes the color of urine less noticeable.

FIG. 1 is a plan view of an incontinence pad 1 according to one embodiment of the present invention. FIG. 2 is an end view of the incontinence pad 1 taken along line II-II' in FIG.

Below, a preferred embodiment of the absorbent article of the present invention will be described in detail with reference to the drawings.

In this specification, the term "planar view" simply refers to "viewing an object (such as an incontinence pad) laid flat on a horizontal surface from above in the vertical direction (especially from the top sheet side if the object is an incontinence pad) in the thickness direction of the object."

In addition, in this specification, in the thickness direction of the absorbent article, the "side that is relatively closer to the wearer's skin when the absorbent article is worn" is referred to as the "skin-facing side." Similarly, in the thickness direction of the absorbent article, the "side that is relatively more distal to the wearer's skin when the absorbent article is worn" is referred to as the "non-skin-facing side."

[Incontinence pads]
One embodiment of the absorbent article of the present invention is an incontinence pad 1. As shown in Fig. 1, the incontinence pad 1 has a longitudinal direction L and a width direction W in a plan view, and has an elliptical outer shape with both ends in the longitudinal direction L protruding in an arc shape outward in the longitudinal direction L. The outer shape of the absorbent article of the present invention is not limited to this form, and any shape (e.g., rectangular, elliptical, hourglass, etc.) and size can be adopted according to various applications, usage modes, etc.

As shown in FIG. 2, the incontinence pad 1 mainly comprises, in the thickness direction T, a liquid-permeable top sheet 2 located on the skin-facing side, a liquid-impermeable back sheet 3 located on the non-skin-facing side, and a liquid-absorbent absorber 4 located between them. In this embodiment, the incontinence pad 1 further comprises a pair of side sheets 5, 5, etc. located on the skin-facing side of the top sheet 2 and extending in the longitudinal direction L at both ends in the width direction W.

The incontinence pad 1 contains an adsorbent that adsorbs the odor and color of urine. In this embodiment, the adsorbent is disposed inside the absorbent body 4 of the incontinence pad 1. The adsorbent has an L* value of 10 or more in the L*a*b* color system, and has a gray to white color. Furthermore, the adsorbent has pores with a pore size of 1.5 to 2.0 nm with a volume of 0.006 mL/g or more, and micropores with a pore size of 0.3 to 0.8 nm with a volume of 0.050 mL/g or more.

This adsorbent is capable of adsorbing and retaining pigment components (e.g., urobilin) in the wearer's urine discharged into the incontinence pad 1 in pores with a pore size of 1.5 to 2.0 nm. The pigment components retained in the pores are difficult to see from the outside because they are surrounded and hidden by non-pore portions (non-pore portions) that have a gray to white color with an L* value of 10 or more in the L*a*b* color system. In addition, the adsorbent has pores with a volume of 0.006 mL/g or more, so that it can adsorb and retain a sufficient amount of pigment components.

Furthermore, this adsorbent is capable of adsorbing and retaining odorous components that cause urine odor (e.g., ammonia, hydrogen sulfide, methyl mercaptan, trimethylamine, etc.) in micropores with a pore size of 0.3 to 0.8 nm. In addition, the adsorbent has micropores with a volume of 0.050 mL/g or more, so that it can adsorb and retain a sufficient amount of odorous components.

Therefore, this adsorbent can suppress the odor of urine and make the color of urine less noticeable without placing any other components (e.g., a concealing sheet or masking material) on the incontinence pad 1 other than the adsorbent.

As a result, the incontinence pad 1 containing such an adsorbent is less likely to have structural constraints, and is able to suppress the odor of urine and make the color of urine less noticeable. Furthermore, since being "white" is highly effective in creating a sense of cleanliness, such an incontinence pad 1 has the advantage of giving the user a positive impression of cleanliness in that it is white before use and remains white after use.

Below, we will explain in more detail one embodiment of the adsorbent that adsorbs urine odor and color and is used in the present invention.

[Adsorbent]
In one embodiment of the present invention, the adsorbent is an adsorbent that adsorbs the odor and color of urine, and has a color with an L* value of 10 or more in the L*a*b* color system, that is, a gray to white color. Furthermore, this adsorbent has pores with a pore size of 1.5 to 2.0 nm in a volume of 0.006 mL/g or more, and micropores with a pore size of 0.3 to 0.8 nm in a volume of 0.050 mL/g or more. The adsorbent is not particularly limited in terms of its structure other than such appearance color, pores, and micropores. For example, the adsorbent may be composed of a plurality of porous particles or porous fibers, or may be composed of a porous molded product having a predetermined shape.

(Exterior color)
The external color of the adsorbent is not particularly limited as long as it is a color with an L* value of 10 or more in the L*a*b* color system, but a color with an L* value of 40 or more is preferable, a color with an L* value of 70 or more is more preferable, and a color with an L* value of 80 or more (a white-based color) is particularly preferable.

In addition, when the adsorbent is disposed at a position on the non-skin-facing side of the top sheet in the thickness direction of the absorbent article (e.g., on the surface or inside of the absorbent body), it is preferable that the appearance color of the adsorbent is such that the L* value of the surface on the skin-facing side of the top sheet is 75 or more. If the L* value of the surface on the skin-facing side of the top sheet is 75 or more, the absorbent article gives a clean impression to the wearer when first using the absorbent article.

<Method of measuring the L* value of the L*a*b* color system>
The L* value of the L*a*b* color system of the adsorbent and the surface of the top sheet can be measured using a commercially available colorimeter in accordance with JIS Z 8722. An example of a commercially available colorimeter is the color difference meter ZE6000 (standard white board [X=93.19, Y=95.20, Z=112.28], reflection measurement diameter 30 mm) manufactured by Nippon Denshoku Industries Co., Ltd. The L* value is measured five times for each sample, and the average value is used.

(pore)
The pores (pore diameter 1.5 to 2.0 nm) of the adsorbent can sufficiently adsorb and retain the pigment components of urine if they have a volume of 0.006 mL/g or more. However, from the viewpoint of more reliably adsorbing and retaining the pigment components of urine, the volume of the pores having a pore diameter of 1.5 to 2.0 nm is preferably 0.008 mL/g or more, more preferably 0.010 mL/g or more, and particularly preferably 0.040 mL/g or more. The upper limit of the volume of the pores having a pore diameter of 1.5 to 2.0 nm is not particularly limited, but from the viewpoint of ease of production, etc., the volume can be, for example, 1.5 mL/g or less.

(Micropores)
The micropores (pore diameter 0.3 to 0.8 nm) of the adsorbent can sufficiently adsorb and retain odorous components of urine if they have a volume of 0.050 mL/g or more. However, from the viewpoint of more reliably adsorbing and retaining odorous components of urine, the volume of the micropores having a pore diameter of 0.3 to 0.8 nm is preferably 0.060 mL/g or more, more preferably 0.070 mL/g or more, and particularly preferably 0.080 mL/g or more. There is no particular upper limit on the volume of the pores having a pore diameter of 0.3 to 0.8 nm, but from the viewpoint of ease of manufacture, the volume can be, for example, 1.5 mL/g or less.

In addition to the above-mentioned fine and micropores, the adsorbent preferably also has fine pores (large pores) with a pore size of 4.0 to 15 nm. Such large pores can adsorb and retain protein components (e.g., albumin) contained in urine. Therefore, an adsorbent that further has such large pores can fundamentally remove not only odorous components contained in urine, but also odors derived from protein components.

<Method of measuring pore size and volume>
The pore size and volume of various pores in the adsorbent can be measured according to JIS Z 8831-2 (Pore size distribution and pore characteristics of powders (solids) - Part 2: Measurement method of mesopores and macropores by gas adsorption) and JIS Z 8831-3 (Pore size distribution and pore characteristics of powders (solids) - Part 3: Measurement method of micropores by gas adsorption). The adsorbate gas used for gas adsorption is selected according to the pore size of the pore to be measured as follows. That is, when measuring pores with a pore size of 1.5 to 2.0 nm or more, argon (measurement range 0.4 to 100 nm) is used, and when measuring micropores with a pore size of 0.3 to 0.8 nm, carbon dioxide gas (measurement range 0.3 to 1.5 nm) is used. This measurement method can be performed using a commercially available fully automatic gas adsorption measurement device.

As mentioned above, the adsorbent is not particularly limited in terms of its structure other than its external color and its pores and micropores, but it is preferable that the adsorbent is composed of a plurality of porous particles. When the adsorbent is composed of a plurality of particles, it has the advantage that it is easy to ensure a specific surface area of a certain level or more and is also easy to handle.

(Particle size)
When the adsorbent is made of such a plurality of particles, it is more preferable that the adsorbent is made of a plurality of particles having a particle size of 500 μm or less. When the adsorbent is made of a plurality of particles having a particle size of 500 μm or less, the surface area of the adsorbent that can come into contact with urine is large, and the odor and color of urine can be adsorbed at a superior adsorption rate.

The particle size of the adsorbent is preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. There is no particular lower limit to the particle size of the adsorbent, but from the standpoint of ease of handling, it is, for example, 0.1 μm or more, and preferably 0.5 μm or more.

<Method of measuring particle size>
The particle size of the adsorbent can be measured using a laser diffraction/scattering type particle size distribution measuring device (for example, LA-920, manufactured by Horiba, Ltd.) under the following predetermined conditions, for example.
Measurement cell: Flow cell Particle size standard: Volume Dispersion medium: 90% ethanol aqueous solution Transmittance: 70-90%
Sample concentration: 0.1%

(Constituent Materials)
The material constituting the adsorbent is not particularly limited as long as it has pores with a pore size of 1.5 to 2.0 nm in a volume of 0.006 mL/g or more and micropores with a pore size of 0.3 to 0.8 nm in a volume of 0.050 mL/g or more, and any porous substance can be used. Examples of such porous substances include porous substances such as activated carbon, silica gel, activated alumina, activated clay, acid clay, synthetic zeolite, and porous synthetic polymers.

Activated carbon that can be used as an adsorbent is not particularly limited, but examples include chemically activated activated carbon and steam activated activated carbon. Furthermore, examples of chemically activated activated carbon include zinc chloride activated activated carbon and phosphoric acid activated activated carbon.

Synthetic polymers that can be used as adsorbents are not particularly limited, but examples include synthetic polymers such as 2,6-diphenyl-p-phenylene oxide polymers and divinylbenzene-styrene copolymers.

Among the above-mentioned porous substances, it is preferable that the adsorbent contains at least one type of porous substance selected from the group consisting of activated carbon, silica gel, activated alumina, activated clay, synthetic zeolite, and synthetic polymers. These porous substances have the advantage that they can stably exert their adsorption action, and that the pore size of the above-mentioned pores and micropores can be easily controlled. Therefore, an absorbent article containing such an adsorbent can more reliably adsorb the odor and color of urine. It is further preferable that the above-mentioned porous substance is activated carbon in terms of versatility and ease of controlling the pore size of the pores.

In addition, the method for producing a porous material having pores with a pore size of 1.5 to 2.0 nm in a volume of 0.006 mL/g or more and micropores with a pore size of 0.3 to 0.8 nm in a volume of 0.050 mL/g or more is not particularly limited. For example, activated carbon having such pores and micropores can be obtained by appropriately selecting various production conditions such as the type of raw material, the carbonization temperature, and the activation treatment conditions in a production method for activated carbon including a carbonization step of carbonizing raw materials such as plant-derived raw materials at a temperature of 800°C to 1400°C, a step of treating the carbonized activated carbon precursor with an acid (e.g., fluorine compounds such as hydrogen fluoride and hydrofluoric acid) or an alkali (e.g., sodium hydroxide) and an activation treatment step of activating the carbon precursor by a heat treatment using a gas such as oxygen or water vapor as an activator or a chemical treatment using a chemical such as zinc chloride, phosphoric acid, or sulfuric acid as an activator.

The plant-derived raw materials that can be used as raw materials for activated carbon are not particularly limited, and examples include rice, wheat, barley, barnyard millet, millet, straw, rice husks, coconut shells, wakame stems, conifers, vascular plants, ferns, mosses, algae, seaweed, and other plants. These plant-derived raw materials may be used alone or in combination of two or more types.

The structure of the porous material is not particularly limited other than that it has the above-mentioned pores and micropores, and the porous material may have a particulate structure such as a powder, granule, or granular structure, or may have a fibrous structure.

There are no particular limitations on the means for adjusting the appearance color of the adsorbent to a color with an L* value of 10 or more in the L*a*b* color system. For example, the surface of a porous material such as activated carbon may be covered with a white inorganic material to adjust the L* value of the adsorbent to 10 or more, or the adsorbent may be formed using only a porous material with a white color to adjust the L* value of the adsorbent to 10 or more. Examples of porous materials with a white color include synthetic zeolite and acid clay.

In this embodiment, the adsorbent is preferably such that the porous material is covered with at least one white inorganic material selected from titanium oxide, calcium carbonate, zinc oxide, barium sulfate, magnesium oxide, kaolin, and talc. These white inorganic materials have excellent concealing power, so when the adsorbent is composed of the porous material and a white inorganic material covering the porous material, the pigment components of urine adsorbed and held in the pores of the porous material can be made even less visible from the outside. In addition, absorbent articles containing such adsorbents have the advantage of giving the user an even more positive impression of cleanliness.

It is further preferable that the white inorganic substance is a plurality of particles. When the adsorbent is composed of the porous substance and a plurality of white inorganic substance particles covering the porous substance, the odor components and color components of urine can be adsorbed and held in the pores and micropores of the porous substance through the gaps between the particles of the white inorganic substance. In other words, the adsorbent can make the color components adsorbed and held in the pores of the porous substance less visible from the outside without inhibiting the adsorption of the odor components and color components of urine. Therefore, an absorbent article containing such an adsorbent can more reliably suppress the odor of urine while making the color of urine even less noticeable.

Here, the means for covering the surface of the porous material with the white inorganic material is not particularly limited, and for example, the white inorganic material may be attached to the surface of the porous material via any adhesive means such as a binder.

(Location)
The adsorbent thus configured can be disposed at any position of the absorbent article. For example, the adsorbent can be disposed at a position closer to the skin-facing side than the back sheet. Specifically, the adsorbent may be disposed on the surface and/or inside of the top sheet of the absorbent article, or on the surface and/or inside of an intermediate sheet disposed between the top sheet and the absorbent body. Alternatively, the adsorbent may be disposed on at least one of the surface and inside of the absorbent body. Furthermore, in this case, the adsorbent may be disposed on the surface and/or inside of at least one of the absorbent core and the core wrap sheet constituting the absorbent body.

Among these placement positions, it is preferable that the adsorbent is placed at least on the surface or inside of the absorbent. If the adsorbent is placed in such a position where it is likely to come into contact with urine, the adsorbent can more reliably suppress the urine odor and make the color of the urine less noticeable.

(Content)
The content of the adsorbent when the adsorbent is disposed in the absorbent article is not particularly limited as long as it does not impair the effects of the present invention, but the adsorbent is preferably contained in a mass ratio of 0.1 mass% or more relative to the total mass of the absorbent article. When the adsorbent is contained in the absorbent article in such a mass ratio, the adsorbent can more reliably suppress the urine odor and make the color of the urine less noticeable.

It is more preferable that the adsorbent is contained in a mass ratio of 0.5% or more with respect to the total mass of the absorbent article, and it is particularly preferable that the adsorbent is contained in a mass ratio of 1.0% or more with respect to the total mass of the absorbent article. There is no particular upper limit on the content of the adsorbent, and for example, the adsorbent can be contained in a mass ratio of 15% or less with respect to the total mass of the absorbent article. The mass ratio of the adsorbent can be measured as follows.

<Method of measuring mass proportion of adsorbent>
(1) A component member having an adsorbent disposed therein (for example, an absorbent core or a core wrap sheet of an absorbent body) is removed from the absorbent article.
(2) The adsorbent is recovered from the removed component using physical means (e.g., vibration means, etc.) and/or chemical means (e.g., a solvent capable of dissolving the binder component, etc.). At this time, if foreign matter other than the adsorbent (e.g., fiber fragments, etc.) is present, the foreign matter is removed with tweezers or the like while using magnifying observation means such as a microscope or a simple magnifying glass, and only the adsorbent is recovered.
(3) After measuring the mass (g) of the recovered adsorbent, this is divided by the total mass (g) of the absorbent article and multiplied by 100 to calculate the mass percentage (%) of the adsorbent.

The various components of the absorbent article of the present invention will be described in detail below using the incontinence pad 1 of the above-mentioned embodiment. Note that the components of the absorbent article vary depending on the type of absorbent article, the manner of use, etc., and therefore the various components described below are not necessarily essential components for the absorbent article.

(Surface sheet)
In the above-mentioned incontinence pad 1, the top sheet 2 has a vertically elongated outer shape extending from the front edge to the rear edge in the longitudinal direction L of the incontinence pad 1 in a plan view, and extending from the vicinity of one edge to the vicinity of the other edge in the width direction W of the incontinence pad 1, as shown in Fig. 1. The top sheet 2 is arranged on the skin-facing side in the thickness direction T of the incontinence pad 1, as shown in Fig. 2, and is composed of a liquid-permeable sheet-like member that forms a contact surface that can come into contact with the wearer's skin. Examples of liquid-permeable sheet-like members include air-through nonwoven fabrics.

There are no particular limitations on the outer shape, dimensions, basis weight, etc. of the top sheet 2, and any shape, dimensions, basis weight, etc. can be adopted according to the desired liquid permeability, texture, flexibility, strength, etc.

The adsorbent having an L* value of 10 or more in the L*a*b* color system and having the above-mentioned specific pores and micropores may be disposed on the surface of the surface sheet 2 facing the skin and/or the surface not facing the skin, or may be disposed inside the surface sheet 2.

(Back sheet)
In the above-mentioned incontinence pad 1, the back sheet 3 has a vertically elongated outer shape extending from the front edge to the rear edge in the longitudinal direction L of the incontinence pad 1 and from one edge to the other edge in the width direction W of the incontinence pad 1 in a plan view. As shown in Fig. 2, the back sheet 3 is arranged at a position on the non-skin-facing side in the thickness direction T of the incontinence pad 1 and is composed of a liquid-impermeable sheet-like member that prevents excrement such as urine that has permeated the absorbent body 4 from leaking out of the incontinence pad 1. Examples of the liquid-impermeable sheet-like member include a resin film and an SMS nonwoven fabric.

There are no particular restrictions on the outer shape, dimensions, basis weight, etc. of the back sheet 3, and any shape, dimensions, basis weight, etc. can be used according to the desired leak-proofing performance, breathability, strength, etc.

In addition, the adsorbent having an L* value of 10 or more in the L*a*b* color system and having the above-mentioned specific pores and micropores may be disposed on the surface and/or inside the back sheet 3 on the skin-facing side.

In the above-mentioned incontinence pad 1, an adhesive portion may be arranged on the surface of the back sheet 3 that does not face the skin, for adhesively fixing the incontinence pad 1 to the inner surface of the wearer's underwear. In addition, a liquid-impermeable leak-proof sheet may be further provided between the back sheet 3 and the absorbent body 4. Examples of the leak-proof sheet include a resin film made of any thermoplastic resin such as polyethylene or polypropylene.

(Absorbent)
1, in the above-mentioned incontinence pad 1, the absorber 4 has a vertically elongated outer shape extending from near one edge to near the other edge in the longitudinal direction L of the incontinence pad 1, and extending from near one edge to near the other edge in the width direction W of the incontinence pad 1. More specifically, the absorber 4 has a vertically elongated outer shape resembling a gourd, with the central portion in the longitudinal direction L narrowed toward the inward side in the width direction W, in a plan view.

As shown in FIG. 2, the absorbent body 4 is arranged between the top sheet 2 and the back sheet 3 in the thickness direction T of the incontinence pad 1, and is composed of a predetermined water-absorbent material that can absorb and retain urine and other excrement that has permeated the top sheet 2. Specifically, the absorbent body 4 is composed of an absorbent core made of a water-absorbent material, and a core wrap sheet made of a hydrophilic fiber sheet that encases the absorbent core.

The absorbent material constituting the absorbent core is not particularly limited as long as it is capable of absorbing and retaining urine and other excrement, and any absorbent material known in the art can be used. Examples of such absorbent materials include superabsorbent polymers and hydrophilic fibers.

Examples of superabsorbent polymers include powders or granules made of superabsorbent polymers such as sodium acrylate copolymers known in the art, so-called SAPs (Super Absorbent Polymers). Specific examples of superabsorbent polymers include polymers or copolymers of (meth)acrylic acid or alkali metal salts of (meth)acrylic acid, preferably polymers or copolymers of sodium (meth)acrylate. In this specification, (meth)acrylic acid means acrylic acid or methacrylic acid.

On the other hand, specific examples of hydrophilic fibers include pulp fibers, cotton, rayon, acetate, and other cellulosic fibers.

The absorbent core may contain either a superabsorbent polymer or hydrophilic fibers, or may contain both a superabsorbent polymer and hydrophilic fibers.

In the above-mentioned incontinence pad 1, the absorbent 4 is composed of an absorbent core containing a superabsorbent polymer and a core wrap sheet made of a hydrophilic fiber sheet. An adsorbent having an L* value of 10 or more in the above-mentioned L*a*b* color system and having the above-mentioned specific pores and micropores is disposed inside the absorbent 4. More specifically, the adsorbent is dispersed and disposed together with the superabsorbent polymer in the absorbent core. That is, the adsorbent is disposed in contact with the superabsorbent polymer. In this way, when the adsorbent is disposed in a position that is particularly likely to come into contact with urine, the adsorbent can more reliably suppress the odor of urine and make the color of urine less noticeable.

The adsorbent may be disposed on the surface of the absorbent core, or on the inner surface of the core wrap sheet that may come into contact with the absorbent core. Furthermore, the adsorbent may be disposed on the outer surface of the core wrap sheet (particularly the surface facing the skin), or may be disposed inside the core wrap sheet.

The hydrophilic fiber sheet constituting the core wrap sheet is not particularly limited as long as it is permeable to excrement such as urine, and any hydrophilic fiber sheet known in the art can be used. Examples of such hydrophilic fiber sheets include tissues made primarily from bleached softwood kraft pulp and having a basis weight of about 10.0 g/m ² to 20.0 g/m ² .

There are no particular limitations on the external shape, dimensions, basis weight, etc. of the absorbent body 4, and any shape, dimensions, basis weight, etc. can be adopted according to the desired absorbency, flexibility, strength, etc.

(Side seat)
In the above-mentioned incontinence pad 1, the pair of side sheets 5, 5 have a pair of band-like outer shapes extending in the longitudinal direction L at both ends in the width direction W of the incontinence pad 1 in a plan view, as shown in Fig. 1. The pair of side sheets 5, 5 are arranged at the skin-facing side of the top sheet 2 in the thickness direction T of the incontinence pad 1, as shown in Fig. 2. The outer end of each of the pair of side sheets 5, 5 in the width direction W is joined to the surface of the skin-facing side of the back sheet 3 to form a fixed end, while the inner end in the width direction W is not joined to any component and forms a free end.

When worn, each of the pair of side sheets 5, 5 deforms so that the incontinence pad 1 curves in the longitudinal direction L, causing the free ends, which are the inner ends in the width direction W, to stand up, forming a pair of leakage prevention walls for preventing leakage of excrement such as urine. The pair of side sheets 5, 5 can be formed from a hydrophilic or hydrophobic sheet-like material. Examples of hydrophilic or hydrophobic sheet-like materials include hydrophilic or hydrophobic nonwoven fabrics and resin films.

There are no particular restrictions on the external shape, dimensions, weight, etc. of each of the pair of side sheets 5, 5, and any shape, dimensions, weight, etc. can be used according to the desired leak-proofing performance, etc.

The adsorbent having the above-mentioned L* value of 10 or more in the L*a*b* color system and the above-mentioned specific pores and micropores may be disposed on the surface of the skin-facing side and/or the non-skin-facing side of the pair of side sheets 5, 5, or may be disposed inside the pair of side sheets 5, 5.

(Application)
In addition to the incontinence pads of the above-described embodiments, the present invention can be applied to various absorbent articles, such as disposable diapers, sanitary napkins, panty liners, and absorbent pads.

The scope of application of the present invention is not limited to absorbent articles. The present invention can be applied to a wide range of applications that require urine treatment.

[Processing method]
Another embodiment of the present invention is a method for treating urine, comprising contacting urine with an adsorbent that adsorbs the odor and color of urine. In this embodiment, the adsorbent has an L* value of 10 or more in the L*a*b* color system, and further has pores with a pore size of 1.5 to 2.0 nm in a volume of 0.006 mL/g or more and micropores with a pore size of 0.3 to 0.8 nm in a volume of 0.050 mL/g or more.

The urine treatment method of this embodiment involves contacting urine with an adsorbent that adsorbs the odor and color of urine, and as described above, the adsorbent is capable of suppressing the odor of urine and making the color of urine less noticeable without requiring any other components. Therefore, the urine treatment method of this embodiment using such an adsorbent is less likely to cause structural constraints, and is capable of suppressing the odor of urine and making the color of urine less noticeable, so it can be applied to a wide range of applications that require urine treatment, such as absorbent articles.

The present invention is not limited to the above-described embodiments or the following examples, and can be appropriately combined, substituted, modified, etc., without departing from the purpose and intent of the present invention.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1
0.9 g of activated carbon (chemically activated carbon, manufactured by Osaka Gas Chemicals Co., Ltd., product number: Strong White Eagle, raw material: conifer, particle size (median diameter): 52 μm) as a porous material, 5.4 g of titanium oxide (particle size: 0.25 μm) as a white inorganic material, and 1.31 g of a binder component (a mixture of 0.05 g of 45% alkyl acrylate copolymer liquid, 0.01 g of carboxymethyl cellulose (CMC), and 1.25 g of water) were mixed, and the mixture was dried at 115° C. for 2 hours. Next, the dried mixture was pulverized in a pulverizer to obtain the adsorbent of Example 1 in which the surfaces of the activated carbon particles were covered with a plurality of titanium oxide particles.

Example 2
An adsorbent of Example 2 was obtained in the same manner as in Example 1, except that activated carbon having various pore volumes and the like different from one another (steam-activated activated carbon, manufactured by Osaka Gas Chemicals Co., Ltd., product number: Hakuwashi M, raw material: coniferous wood, particle size (median diameter): 45 μm) was used as the porous substance.

Example 3
The adsorbent of Example 3 was obtained in the same manner as in Example 1, except that a porous carbon material (commercially available (for commercial use), raw material: rice husk, particle size: 10 μm) having various pore volumes and raw materials was used as the porous substance.

Example 4
The adsorbent of Example 4 was obtained in the same manner as in Example 1, except that a porous carbon material (commercially available (for commercial use), raw material: rice husk, particle size: 80 μm or less) having various pore volumes and raw materials was used as the porous substance.

Example 5
The adsorbent of Example 5 was obtained in the same manner as in Example 1, except that a porous carbon material (commercial product (for commercial use), raw material: rice husk, particle size: 200 to 500 μm) having various pore volumes and raw materials was used as the porous substance.

(Comparative Example 1)
An adsorbent of Comparative Example 1 was obtained in the same manner as in Example 1, except that activated carbon having various different pore volumes and raw materials was used as the porous substance (steam-activated activated carbon, manufactured by Osaka Gas Chemicals Co., Ltd., product number: Hakusugi WP, raw material: coconut shell, particle size (median diameter): 25 μm).

The volumes of the pores with a pore size of 1.5 to 2.0 nm and the micropores with a pore size of 0.3 to 0.8 nm of the various porous materials used in the manufacture of Examples 1 to 5 and Comparative Example 1 were measured by the constant volume method using a fully automatic gas adsorption measurement device (AS-iQ-C) manufactured by Anton Paar. The measurement results are shown in Table 1 below.

The L* value of the L*a*b* color system of each adsorbent in Examples 1 to 5 and Comparative Example 1 was measured according to the above-mentioned <Method for measuring L* value in L*a*b* color system>, and the urine color and urine odor adsorption evaluation of each adsorbent was carried out according to the following <Method for evaluating urine color adsorption and urine odor adsorption evaluation>. These measurement and evaluation results are shown in Table 1 below.

<Urine color adsorption evaluation and urine odor evaluation method>
(1) 0.2 g of the adsorbent to be evaluated is placed in a sample bottle of a predetermined volume (for example, 50 mL), and 30 mL of actual adult urine is added to immerse the adsorbent in the urine.
(2) Close the lid of the sample bottle to seal it, and leave it as it is for 15 hours.
(3) After 15 hours, open the lid of the sample bottle, smell the contents, and perform a sensory evaluation of the strength of the urine odor. In the sensory evaluation, a case where the urine odor is barely detectable is judged as "good" (represented by the symbol "O"), and a case where the urine odor is clearly detectable is judged as "poor" (represented by the symbol "X").
(4) The contents after 15 hours of (3) above are filtered to separate the adsorbent and the filtrate.
(5) A predetermined amount of the filtrate is placed in a quartz cell, a standard white plate is placed on the back of the quartz cell, and the b* value of the filtrate is measured in the L*a*b* color system using a colorimeter (Konica Minolta CR-400 color difference meter, standard white plate [Y=93.0, x=0.3139, y=0.3202], measurement diameter/illumination diameter=φ8/φ11 mm). This measured b* value is recorded as the "b* value after adsorption."
(6) As a blank, measure the b* value of the L*a*b* color system of the urine that has not been immersed in the adsorbent in the same manner as in (5) above. This measured b* value is recorded as the "b* value before adsorption."
(7) Calculate the b* value reduction rate (%) of the adsorbent being evaluated based on the following formula, and record this as the "dye adsorption rate (%)."
b* value reduction rate (%)=(b* value before adsorption−b* value after adsorption)/b* value before adsorption×100
(8) From the dye adsorption rate thus obtained, the degree of reduction in urine color is judged based on the following criteria.
◎ (Excellent): Dye adsorption rate exceeds 80%. ◯ (Good): Dye adsorption rate is 80% or less and exceeds 50%. × (Poor): Dye adsorption rate is 50% or less.

As shown in Table 1, it was found that each of the adsorbents in Examples 1 to 5 of the present invention was able to effectively adsorb the color and odor of urine. On the other hand, it was found that the adsorbent in Comparative Example 1 was unable to adequately adsorb the color of urine.

1 Incontinence pad 2 Top sheet 3 Back sheet 4 Absorbent body 5 Side sheet

Claims (7)

1. An absorbent article comprising an adsorbent that adsorbs urine odor and color,
The adsorbent has an L* value of 10 or more in the L*a*b* color system,
The porous medium has pores having a pore diameter of 1.5 to 2.0 nm with a volume of 0.006 mL/g or more, and has micropores having a pore diameter of 0.3 to 0.8 nm with a volume of 0.050 mL/g or more;
The absorbent article includes an absorbent body,
The adsorbent is disposed on at least one of a surface of the absorbent and an interior of the absorbent,
The absorbent body includes an absorbent core including a superabsorbent polymer;
The absorbent article is characterized in that the adsorbent is disposed in contact with the superabsorbent polymer . The absorbent article according to claim 1, characterized in that the adsorbent is made of a plurality of particles with a particle size of 500 μm or less. The absorbent article according to claim 1, characterized in that the adsorbent contains at least one porous material selected from the group consisting of activated carbon, silica gel, activated alumina, activated clay, synthetic zeolite, and synthetic polymers. The absorbent article according to claim 3, characterized in that the porous material of the adsorbent is covered with at least one white inorganic material selected from titanium oxide, calcium carbonate, zinc oxide, barium sulfate, magnesium oxide, kaolin, and talc. The absorbent article according to claim 4, characterized in that the white inorganic material is a plurality of particles. The absorbent article according to claim 1, characterized in that the adsorbent is contained in a mass ratio of 0.1 mass% or more relative to the total mass of the absorbent article. 1. A method for treating urine in an absorbent article , comprising contacting the urine with an adsorbent that adsorbs urine odor and color,
The adsorbent has an L* value of 10 or more in the L*a*b* color system,
The porous medium has pores having a pore diameter of 1.5 to 2.0 nm with a volume of 0.006 mL/g or more, and has micropores having a pore diameter of 0.3 to 0.8 nm with a volume of 0.050 mL/g or more;
The absorbent article includes an absorbent body,
The adsorbent is disposed on at least one of a surface of the absorbent and an interior of the absorbent,
The absorbent body includes an absorbent core including a superabsorbent polymer;
The method of claim 1, wherein the adsorbent is disposed in contact with the superabsorbent polymer .

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