JP7487043B2 - Absorbent articles - Google Patents

Description

The present invention relates to absorbent articles such as disposable diapers.

When absorbent articles such as disposable diapers, sanitary napkins, panty liners (discharge sheets), and incontinence pads are worn, skin rashes may occur due to sweating, etc. For this reason, absorbent articles containing skin care agents have been proposed in order to provide a skin care effect and suppress the occurrence of rashes. As skin care agents, hydrophilic and hydrophobic types are known.
For example, Patent Documents 1 to 3 disclose absorbent articles in which a skin care agent is used in the top sheet that contacts the wearer's skin. Patent Document 1 discloses a top sheet for absorbent articles that contains fibers containing witch hazel extract, 1,3-butylene glycol, and a fiber treatment agent. Patent Document 2 discloses an absorbent article in which an oil layer made of a hydrophilic fiber treatment agent contains vegetable oil and covers the surface of the fibers constituting the nonwoven fabric that forms the skin side sheet. Patent Document 3 discloses an absorbent article in which a higher amount of skin care agent is applied to the low density parts of the top sheet made of a nonwoven fabric sheet in which high density parts and low density parts are distributed in the planar direction than to the high density parts.

Patent No. 4548971 Utility Model Registration No. 3219622 JP 2015-171649 A

In general, when a hydrophobic agent, not limited to skin care agents, is used in the top sheet, the excrement tends to be less absorbed by the absorbent and the liquid tends to be less likely to spread. Also, when a hydrophilic agent, not limited to skin care agents, is used in the top sheet, the excrement liquid absorbed by the top sheet tends to remain on the top sheet.

The present invention relates to an absorbent article with a top sheet that has a good balance between the ease of liquid spreading and the speed at which liquid drains off.

An absorbent article according to one embodiment of the present invention includes a top sheet.
The top sheet includes a fiber layer positioned on the wearer's skin side.
The fiber layer contains a surface treatment agent in which a hydrophilic component, an oily component and a polyhydric alcohol are in a mixed state.

As described above, the absorbent article of the present invention can be made to have a top sheet that has a good balance between the ease of liquid spreading and the speed at which liquid drains off.

FIG. 1 is a diagram showing an example of a disposable diaper as one embodiment of an absorbent article of the present invention, and is a schematic plan view of the skin side (top sheet side) showing the state in which the elastic members of each part are stretched and spread out flat. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. 3 is a schematic perspective view showing an enlarged view of a portion of a topsheet of the disposable diaper. FIG. FIG. 4 is a schematic partially enlarged cross-sectional view of the topsheet for explaining the configuration of the protrusions of the topsheet.

Hereinafter, the absorbent article of the present invention will be described with reference to the drawings, taking a disposable diaper as an example of one embodiment.
<Overall composition of disposable diapers>
As shown in FIG. 1, the disposable diaper 1 of this embodiment is a so-called open-type disposable diaper. The disposable diaper 1 has a vertical direction X corresponding to the front-rear direction of the wearer, and a horizontal direction Y corresponding to the left-right direction of the wearer and perpendicular to the vertical direction X. Furthermore, the disposable diaper 1 has a thickness direction Z perpendicular to both the vertical direction X and the horizontal direction Y. In this specification, when each component is viewed from the direction of the thickness direction Z, it is referred to as a plan view. In this specification, the skin side of each component refers to the side located on the skin side of the wearer when the disposable diaper is worn. In each component, the non-skin side refers to the side located opposite to the skin side of the wearer when the disposable diaper is worn. In addition, with regard to the thickness direction Z, the side close to the skin of the wearer when worn may be referred to as the upper side, and the side close to the clothing may be referred to as the lower side. Hereinafter, the disposable diaper 1 will be referred to as diaper 1.

The diaper 1 is divided into a ventral region A located on the ventral side in the longitudinal direction X, a dorsal region B located on the dorsal side in the longitudinal direction X, and a crotch region C located between the ventral region A and the dorsal region B.
The back region B includes side portions protruding outward in the lateral direction Y from the crotch region C. Fastening tapes 6 are provided on the side edges of the side portions in the lateral direction Y. Similarly, the abdominal region A includes side portions protruding outward in the lateral direction Y from the crotch region C. A landing tape (not shown) for adhering the fastening tape 6 is provided on the non-skin side surface of the abdominal region A. When worn, the back region B and the abdominal region A are adhered to each other by the fastening tape 6 and are positioned together around the hips and waist of the wearer.
The crotch region C is narrower than the ventral region A and the dorsal region B, with leg openings narrowed inward in the lateral direction Y, and is positioned around the wearer's crotch area, including the urination area and anus, when worn.
It should be noted that "when worn" here refers to a state in which the normally expected appropriate wearing position is maintained.

As shown in Figures 1 and 2, the diaper 1 has a top sheet 2, a back sheet 3, an absorbent body 4, side sheets 5, a pair of fastening tapes 6, an intermediate sheet 7, and a leak-proof sheet 8. The diaper 1 has a configuration in which the back sheet 3, the leak-proof sheet 8, the absorbent body 4, the intermediate sheet 7, and the top sheet 2 are laminated in the thickness direction Z. These components are joined together by known joining means such as a hot melt adhesive.

The absorbent body 4 extends along the longitudinal direction X, and is disposed between the top sheet 2 and the back sheet 3. The absorbent body 4 absorbs liquid excrement (hereinafter simply referred to as "liquid") such as urine of the wearer from the surface facing the top sheet 2, and retains the liquid by diffusing it internally.
The absorbent body 4 has an absorbent core 40 and a core wrap sheet 41 .
The absorbent core 40 is mainly composed of an absorbent material capable of retaining liquid. Specifically, the absorbent core 40 has a structure in which a hydrophilic fiber stack is supported with an absorbent polymer, or a structure made of only a water-absorbent polymer, or the like.
The core wrap sheet 41 covers the absorbent core 40 and has a function of, for example, maintaining the shape of the absorbent core 40. The core wrap sheet 41 is formed of, for example, a thin, soft paper such as tissue paper or a liquid-permeable nonwoven fabric.

The top sheet 2 is disposed on the skin side (upper in the thickness direction Z) of the absorbent body 4, and constitutes, for example, the central portion in the lateral direction Y of the skin side of the diaper 1. The top sheet 2 is configured as a liquid-permeable sheet material, and is formed of woven or nonwoven fabric made of synthetic or natural fibers. Details of the top sheet 2 will be described later.

The intermediate sheet 7 is placed between the top sheet 2 and the absorbent body 4. The intermediate sheet 7 can be made of nonwoven fabric obtained by various manufacturing methods. The intermediate sheet 7 is placed from the viewpoint of improving the permeability of liquid from the top sheet 2 to the absorbent body 4 and preventing liquid absorbed by the absorbent body 4 from returning to the top sheet 2.

The back sheet 3 is disposed on the non-skin side (lower in the thickness direction Z) of the absorbent 4, and constitutes, for example, almost the entire non-skin side of the diaper 1, forming the exterior of the diaper 1 when worn. The back sheet 3 is preferably leak-proof, and is formed, for example, from a sheet material that has properties such as low liquid permeability, water vapor permeability, and water repellency.

The pair of side sheets 5 are disposed on the lateral sides of the top sheet 2 in the lateral direction Y, and, for example, constitute the lateral sides in the lateral direction Y of the skin side of the diaper 1. The side sheets 5 are desirably leak-proof, and are formed of a sheet material having, for example, properties such as poor liquid permeability, water vapor permeability, and water repellency. The pair of side sheets 5 are disposed such that the central sides in the lateral direction Y overlap the top sheet 2, and the lateral sides in the lateral direction Y extend to the outside of the top sheet 2 and are joined to the back sheet 3.
In the diaper 1, the side sheets 5 form a sheet for forming three-dimensional gathers. The side end portions of the side sheets 5 at the center in the lateral direction Y are free ends that are not joined to the top sheet 2 or the like, at least in the crotch region C, and are provided with elastic members 51. The elastic members 51 extend in the longitudinal direction X in the crotch region C, and may extend, for example, to parts of the abdominal region A and the dorsal region B. The provision of the elastic members 51 forms three-dimensional gathers.
Elastic members 52 that stretch in the vertical direction X, for example, are disposed near the side ends of the side sheets 5 on the outer side in the horizontal direction Y, thereby forming leg gathers that fit snugly around the legs of the wearer when worn.
The elastic members 51 and 52 are thread-like or band-like elastic members that are stretchable in the longitudinal direction X.

The pair of fastening tapes 6 have fastening parts 61 made of male members of a mechanical hook-and-loop fastener. A landing tape made of a female member of a mechanical hook-and-loop fastener is provided on the non-skin side of the abdominal region A of the diaper 1. The fastening parts 61 of the fastening tapes 6 can be removably attached to the landing tape.

The leak-proof sheet 8 is made of a liquid-impermeable or liquid-difficult-to-permeate resin film and covers the skin side of the back sheet 3.

<Surface sheet>
[Surface sheet structure]
In the diaper 1 of this embodiment, as shown in FIGS. 2 to 4, the topsheet 2 is constructed by laminating a second sheet 22 and a first sheet 21 formed on the second sheet 22 .
The first sheet 21 is composed of an uneven fiber layer (hereinafter simply referred to as "fiber layer") having a plurality of protrusions 23. The fiber layer is a nonwoven fabric layer. The protrusions 23 protrude in a dome shape toward the wearer's skin. The first sheet 21 and the second sheet 22 are partially joined and fixed by thermal fusion at a number of joints 24. The joints 24 form recesses in the uneven top sheet 2. The non-jointed parts of the first sheet 21 other than the joints 24 form the protrusions 23. The insides of the protrusions 23 are hollow.
The first sheet 21 has a skin side 21a which is positioned against the wearer's skin when the diaper 1 is worn, and a non-skin side 21b opposite to the skin side 21a.
The joints 24 forming the convex portions 23 and the concave portions are arranged alternately in rows in one direction (the vertical direction X in FIG. 3), and such rows are formed in multiple rows in a direction perpendicular to the one direction (the horizontal direction Y in FIG. 3).

The first sheet 21 and the second sheet 22 each consist of a sheet-like material made of a fibrous material. This sheet-like material is substantially non-stretchable. As the sheet-like material, various nonwoven fabrics can be used, such as nonwoven fabrics manufactured by the carding method, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics and needlepunch nonwoven fabrics, and meltblown nonwoven fabrics, spunlace nonwoven fabrics and needlepunch nonwoven fabrics.

The top sheet 2 having a laminated structure in which the first sheet 21 and the second sheet 22 are partially joined by thermal fusion at the joint 24 and has a plurality of protrusions 23 can be manufactured, for example, using the manufacturing method described in JP-A-2004-174234.
That is, the sheet-like material of the nonwoven fabric to be the first sheet 21 is intermittently stretched and processed to have a concave-convex shape by being interleaved between two gear rolls having a concave-convex shape on the peripheral surface. In the sheet-like material processed to have a concave-convex shape in this way, the stretched portion forms the convex portion 23. On the other hand, the non-stretched portion forms the joint portion 24 when the top sheet 2 is formed. The sheet-like material to be the first sheet 21 having the plurality of convex portions 23 formed thereon is superimposed on the sheet-like material to be the second sheet 22, and the superimposed material is pressed between two rolls, at least one of which is heated to a predetermined temperature, to be partially joined. As a result, the first sheet 21 and the second sheet 22 are partially joined by heat fusion at the joint portion 24, and the top sheet 2 is manufactured. The surface of the top sheet 2 facing the first sheet 21 has concave-convex shapes. On the other hand, the surface of the top sheet 2 facing the second sheet 22 is almost flat.
The convex portions 23 of the first sheet 21 manufactured in this manner have a relatively low fiber density compared to the joint portions 24. Therefore, when the diaper 1 is worn, the convex portions 23 are mainly in contact with the wearer's skin 9, and the contact surface of the topsheet 2 with the wearer's skin can be softened. This improves the feel against the skin and also suppresses the occurrence of skin troubles such as redness of the skin 9 covered by the diaper 1 due to friction with the topsheet 2, etc. On the other hand, the joint portions 24 have a higher fiber density than the convex portions 23, and are more likely to draw in liquid and have higher liquid absorbency.

As shown in FIG. 4, the first sheet 21 has a laminated structure in which an upper layer 26 and a lower layer 27 are laminated. In FIG. 4, the upper layer 26 is shown in a thick line and the lower layer 27 is shown in a thin line. In FIG. 4, the circular black dots represent fused portions of the fibers.

The upper layer 26 is made into a nonwoven fabric using first fibers having a core-sheath structure as raw fibers, which are coated with a surface treatment agent described below.
The first fiber can preferably be a core-sheath fiber, a side-by-side fiber, etc., and is particularly preferably a core-sheath fiber. A typical first fiber has a core component of PET (polyethylene terephthalate) and a sheath component of PE (polyethylene), and the core-sheath ratio is preferably 20/80 to 80/20 by mass. The fineness of the first fiber is preferably 1.5 dtex or more and 5.0 dtex or less. The core-sheath ratio refers to the mass ratio (core/sheath) of the resins constituting the core and the sheath.
The surface treatment agent does not only mean a mixture containing three components, i.e., a hydrophilic component, an oily component, and a polyhydric alcohol, but also includes a state in which the three components, i.e., a hydrophilic component, an oily component, and a polyhydric alcohol, are present on or inside the fiber in a mixed state. In this embodiment, the hydrophilic component may include a hydrophilic surfactant, a hydrophilic extract, etc. In addition, in this embodiment, the oily component may include a hydrophobic surfactant, a water-repellent compound, or a hydrophobic extract. In this embodiment, it is preferable to use a hydrophilic extract as the hydrophilic component and a hydrophobic extract as the oily component, and the hydrophilic extract and the hydrophobic extract include a skin care agent. Details of the surface treatment agent will be described later. Note that the hydrophilic surfactant belongs to the definition of "hydrophilic" described later, and for example, in the case of a nonionic surfactant, the HLB (Hydrophilic-Lipophilic-Balance) of the Griffin method is 3 or more, preferably 5 or more, as a guideline.

The lower layer 27 is a nonwoven fabric made by mixing two types of fibers: a first fiber having a core-sheath structure as the raw fiber and coated with a surface treatment agent, and a second fiber having a core-sheath structure as the raw fiber and coated with a hydrophilic surfactant.
As the second fiber, a core-sheath fiber, a side-by-side fiber, etc. can be preferably used, and a core-sheath fiber is particularly preferable. A representative second fiber has a core component made of PET (polyethylene terephthalate) and a sheath component made of PE (polyethylene), and the core-sheath ratio is preferably 20/80 to 80/20 by mass.

The amount of the surface treatment agent applied to the first fibers used in the upper layer 26 is the same as that of the first fibers used in the lower layer 27. The amount (basis weight) of the first fibers may be the same or different between the upper layer 26 and the lower layer 27.
The second fiber used in the lower layer 27 is thinner in sheath than the first fiber and has a higher core-sheath ratio. Here, the "core-sheath ratio" refers to the mass ratio of core/sheath (former/latter) in one fiber having a core-sheath structure. Since the second fiber has a thinner sheath than the first fiber, when the fiber is made into a nonwoven fabric, the fusion points between the fibers are fewer and the fusion area is smaller. Therefore, by using at least two types of fibers with different core-sheath ratios, the fusion area of the fibers in the first sheet 21 can be reduced compared to the case where only the first fiber with a lower core-sheath ratio is used. Since the surface treatment agent is likely to accumulate at the fusion points between the fibers, the uneven distribution of the surface treatment agent at the fusion points is suppressed by reducing the fusion area. As a result, the localized liquid residue of the surface treatment agent in the first sheet 21 is suppressed, and the liquid absorbency of the first sheet 21 can be improved.
In addition, fibers with a higher core-sheath ratio, such as the second fiber, have fewer fusion points between fibers than fibers with a lower core-sheath ratio, such as the first fiber, and are therefore more likely to follow movement. For this reason, the topsheet 2 of this embodiment contains the second fiber in the lower layer 27, which has the advantage that the entire topsheet can move more easily and fluffing can be suppressed when worn.
In this manner, by using the first fibers 31 and the second fibers 32 having different core-sheath ratios, the first sheet 21 can be made gentle to the wearer's skin and has excellent liquid absorbency.

Furthermore, a surface treatment agent consisting of a mixture of a hydrophilic component, an oily component, and a polyhydric alcohol is applied to the first fibers constituting a part of the upper layer 26 and the lower layer 27. In this embodiment, the hydrophilic component contains a hydrophilic surfactant and a hydrophilic extract, and the oily component contains a hydrophobic extract.
In contrast, only a hydrophilic surfactant is applied to the second fibers constituting a part of the lower layer 27. In other words, the second fibers do not contain a hydrophobic extract as an oily component, a polyhydric alcohol, or a hydrophilic extract which is one of the hydrophilic components. Since the second fibers are thin-sheath fibers and have high friction between the fibers, by applying only a hydrophilic surfactant to the second fibers, peeling of the hydrophobic extract and hydrophilic extract in the lower layer 27 is suppressed.

In this embodiment, a skin care agent can be used for the oily component (hydrophobic extract) and hydrophilic component (hydrophilic extract) contained in both the upper layer 26 and the lower layer 27. The content of the skin care agent per unit area of the nonwoven fabric is greater in the upper layer 26 than in the lower layer 27. This allows the skin care effect in the early stages of wearing the diaper 1 to be achieved in the upper layer 26, which is closer to the wearer's skin, and the sustained skin care effect can be achieved in the lower layer 27. A method for measuring the content of the skin care agent per unit area will be described later.

The lower layer 27 is formed by mixing and fusing a first fiber having a relatively large content of the surface treatment agent with a second fiber having a small content of the surface treatment agent. Here, the term "relatively small" includes cases where the surface treatment agent is not contained.
By using the second fibers with a relatively low content of surface treatment agent, it is possible to adjust the fiber bonding strength in the lower layer 27. In other words, by using the second fibers with a relatively low content of surface treatment agent, it is possible to reduce the influence of the change in viscosity of the hydrophilic surfactant caused by blending a skin care agent in the sheet. As an example of the influence of the change in viscosity of the hydrophilic surfactant, an increase in the viscosity of the hydrophilic surfactant may cause the fibers to stick together and become less mobile, increasing friction with the skin, or a decrease in the viscosity of the hydrophilic surfactant may cause fluffing.

In this embodiment, both the upper layer 26 and the lower layer 27 contain a surface treatment agent that includes a hydrophilic component, an oily component, and a polyhydric alcohol, so that the top sheet 2 can maintain good liquid absorption while maintaining a state in which little liquid remains.

By using a top sheet 2 having convex portions 23, which is made up of a first sheet 21 and a second sheet 22, in a diaper 1, when the diaper is worn, liquid from the wearer penetrates into the convex portions 23 from their tops in the top sheet 2, and the liquid further diffuses and drains inside the convex portions 23, thereby improving the speed at which liquid is absorbed into the absorbent body 4.

(Surface treatment agent)
As described above, the surface treatment agent contains a hydrophilic component, an oily component, and a polyhydric alcohol. Specific examples are given below. A "skin care agent" is an agent that provides a skin care effect to the wearer. The "skin care effect" refers to the general efficacy of preventing skin rashes, reducing inflammation, preventing scratches, and having antibacterial properties to normalize the condition of the skin.

A hydrophilic component is a hydrophilic component that is water-soluble or water-dispersible. More specifically, a hydrophilic component is one that dissolves or disperses in an amount of 1 g or more when 10 g of the component is mixed in 1 L of ion-exchanged water and then left to stand for 24 hours, preferably one that dissolves or disperses in an amount of 5 g or more, more preferably one that dissolves in an amount of 1 g or more, even more preferably one that dissolves in an amount of 5 g or more, and most preferably one that dissolves completely.

As the hydrophilic component, a hydrophilic surfactant or a hydrophilic plant extract can be preferably used. In the present invention, the hydrophilic component does not include a polyhydric alcohol component. When the hydrophilic component includes a hydrophilic surfactant, representative examples include anionic surfactants, nonionic surfactants, and amphoteric surfactants.

Examples of anionic surfactants include those having a structure in which the hydrophobic group is an alkyl group or an alkylene group with an alkyl chain length of 12 to 32, and the hydrophilic group is a sulfonate, sulfate, carboxylate, or the like. The salt of the hydrophilic group is preferably sodium or potassium.

The nonionic surfactant preferably contains an alkyl group, an alkylene group, a silicone group, etc. as a hydrophobic group, and a polyethylene oxide type, a polyol (polyhydric alcohol) type, a block polymer type, a nitrogen-containing type, etc. as a hydrophilic group structure. The polyethylene oxide type nonionic surfactant preferably contains a polyoxyethylene alkyl ether, a polyoxyethylene fatty acid ester, etc. The polyol (polyhydric alcohol) type nonionic surfactant preferably contains a sorbitan monoalkylate, a polyoxyethylene sorbitan monoalkylate, a glycerol monoalkylate, a polyglyceryl monoalkylate, an alkyl glucoside, a pentaerythritol monoalkylate, etc. The block polymer type nonionic surfactant preferably contains a polyoxyethylene polyoxypropylene glycol alkyl ether, a polyoxyethylene polyoxypropylene alkyl ether, etc.
For nonionic surfactants, HLB (Hydrophilic-Lipophilic Balance) is often used as an index of hydrophilicity/hydrophobicity. In the range that satisfies the hydrophilicity index in this specification, the HLB according to the Griffin method is preferably 3 or more, and more preferably 5 or more.

Examples of amphoteric surfactants include imidazoline, betaine, and amine oxide types, but amidobetaine, amidosulfobetaine, and carbobetaine types are preferably used.

When plant extracts are included as hydrophilic components, it is preferable to include those with skin care effects, such as peach leaf extract, witch hazel extract, bamboo leaf extract, etc. The plant extracts, which are hydrophilic components, dissolve or disperse in the liquid, such as urine, supplied to the top sheet 2, and transfer to the skin, thereby providing a skin care effect. In particular, peach leaf extract is preferable, as it has antibacterial and anti-inflammatory effects and functions as a hydrophilic skin care agent.

As the oily component, fatty acids and fatty acid glycerides, silicone oils, etc. can be used, but preferably, unsaturated fatty acids or unsaturated fatty acid glycerides are included. As the unsaturated fatty acid glycerides, monoesters, diesters, or triesters of fatty acids having 12 to 30 carbon atoms and 1 to 6 unsaturated bonds and glycerin are preferably included, and triesters are particularly preferred. As the oily component containing such unsaturated fatty acids, hydrophobic extracts that are natural product extracts such as argan oil and shea butter, and hydrophobic compounds having functions such as skin care, etc. can be used. Hydrophobic vegetable oils containing unsaturated fatty acids or unsaturated fatty acid glycerides are preferred because they have a high skin care effect. In addition, argan oil is particularly preferred because it can maintain the balance between moisture and oil in the skin, prevent dryness, and function as a hydrophobic skin care agent. In addition, argan oil contains a lot of unsaturated fatty acids such as oleic acid and linoleic acid, has a strong ability to remove active oxygen, and can reduce skin damage caused by, for example, sunburn. In addition, unsaturated fatty acids are expected to have a skin barrier effect, and can move to the skin together with hydrophilic skin care agents to improve the skin care effect.
The oily component is a composition or compound that has no or very low water solubility and water dispersibility. More specifically, the oily component refers to a component that dissolves in an amount of less than 1 g when 10 g of the component is mixed in 1 L of ion-exchanged water and then left to stand for 24 hours, preferably dissolves in an amount of 0.1 g or less, and particularly preferably does not dissolve at all.

As the polyhydric alcohol, an alcohol having 2 to 4 carbon atoms can be used. Typically, 1,3-butylene glycol is used. By using 1,3-butylene glycol, the moisturizing effect and lubricity are improved. By improving the lubricity, the friction between the skin and the nonwoven fabric can be reduced, and damage to the skin can be suppressed. 1,3-butylene glycol is a moisturizing liquid water-soluble base component, which has a smooth feel and is not sticky, keeps the skin moist, and functions as a hydrophilic skin care agent. In addition to being used as a moisturizing agent, 1,3-butylene glycol is also used as a solvent. In this embodiment, 1,3-butylene glycol is used as an extraction solvent for peach leaf extract. 1,3-butylene glycol promotes the compatibility of each component. As a result, in the nonwoven fabric manufactured using the surface treatment agent according to this embodiment, the phase separation and peeling of oily components such as argan oil is suppressed, so that the hydrophilic components, oily components, and polyhydric alcohol that constitute the surface treatment agent can be efficiently contained in the nonwoven fabric. Although 1,3-butylene glycol is used as an example here, any polyhydric alcohol with 2 to 4 carbon atoms will have the same effect, and propylene glycol, for example, can also be used. Propylene glycol can also be used as an extraction solvent for hydrophilic extracts.

In this embodiment, the fibers contain a mixture of hydrophilic components, oily components, and polyhydric alcohols, and the oily components and polyhydric alcohols are preferably those that are liquid or have high fluidity at 36°C. In particular, when functional agents that can migrate to the wearer's skin and perform a specific function such as skin care are selected as the hydrophilic and oily components, it is preferable that these components have high fluidity in the mixed state from the viewpoint of migration to the skin. In that case, by using a hydrophilic surfactant that is solid or semi-solid at 36°C as the hydrophilic component, a hydrophilic plant extract using an oily component that is liquid at 36°C or a polyhydric alcohol as a solvent can be stably attached to the fibers, which is preferable in that it is possible to suppress the above-mentioned components from migrating excessively from the top sheet 2 to other components constituting the absorbent article in the scene of use. In particular, in the case of the above-mentioned liquid functional agent or a mixture containing a liquid functional agent, it is preferable in that the amount of the functional agent migrating to the wearer's skin is easily maintained when the migration of the functional agent from the top sheet 2 to other components constituting the absorbent article is suppressed in the scene of use.

It is preferable to use natural product extract components as components contained in the surface treatment agent. For example, the skin of infants who wear the diaper 1 is thinner and has a poorer barrier function than that of adults, so the use of natural product extract components makes it less likely for allergic reactions to occur. In addition, the use of natural product extract components makes it less likely for skin problems such as redness to occur on the skin inside the diaper to occur. The use of natural product extract components also gives consumers a sense of security and a refreshing image.

In this embodiment, the top sheet 2 is manufactured using a surface treatment agent composed of a mixture of a hydrophilic component, an oily component, and a polyhydric alcohol. In this way, by including a polyhydric alcohol in the surface treatment agent, the compatibility of the hydrophilic component and the oily component is promoted. By manufacturing a nonwoven fabric using such a surface treatment agent, it is possible to obtain a top sheet 2 that has good liquid absorption properties and leaves little liquid on the sheet, and can suppress the hydration of the skin and the occurrence of skin troubles such as redness of the skin inside the diaper 1, and can provide a comfortable wearing experience for the wearer.
Here, liquid spreading refers to the spreading of liquid between the fibers that make up the nonwoven fabric. When liquid is dropped onto the nonwoven fabric, the liquid spreads between the fibers and a liquid film is formed between the fibers. The liquid cutting speed is expressed as the time from when the liquid spreads between the fibers until the liquid film breaks and disappears. The liquid cutting state is when the liquid film breaks and no liquid remains between the fibers.
Furthermore, since a functional agent, a skin care agent in this embodiment, is used as the hydrophilic component and oily component contained in the surface treatment agent, a skin care effect is exerted and the occurrence of skin troubles can be further suppressed.

The amount of the hydrophilic component, oily component, and polyhydric alcohol attached to the fiber is as follows. The hydrophilic component is preferably 0.1% by mass or more and 150% by mass or less relative to the fiber mass in order to further enhance the effects of the present invention, and is preferably 0.2% by mass or more and 50% by mass or less in order to balance the feeling of use. The oily component is preferably 1×10 ⁻⁴ % by mass or more and 0.5% by mass or less, particularly 2×10 ^−4% by mass or more and 0.1% by mass or less relative to the fiber mass, which is preferable because it is easy to balance the effects of the present invention and the feeling of use. The polyhydric alcohol is preferably 3×10 ⁻⁴ % by mass or more, particularly 8×10 ⁻⁴ % by mass or more relative to the fiber mass in order to realize the effects of the present invention at a high level, but from the viewpoint of balance with the feeling of use, the upper limit is preferably 1% by mass or less, particularly 0.5% by mass or less.

From the viewpoint of liquid spreadability, it is preferable that the hydrophilic component is 50% by mass or more and less than 100% by mass, particularly 70% by mass or more and 98% by mass, based on the total mass of the hydrophilic component, oily component, and polyhydric alcohol. From the viewpoint of liquid permeability and usability, it is preferable that the oily component is 0.05% by mass or more and 20% by mass or less based on the total mass, and from the same viewpoint, the upper limit is preferably 5% by mass or less. If the polyhydric alcohol is 0.1% by mass or more and 98% by mass, it becomes easier to mix the hydrophilic component and the oily component and the usability is good, and from the viewpoint of making the mixed state more uniform, it is more preferable that the polyhydric alcohol is 0.2% by mass or more and 96% by mass or less.

(Method of manufacturing the top sheet)
An example of a method for producing the topsheet 2 will now be described.
First, a method for producing the first sheet 21 before the unevenness processing will be described.
An upper layer web is manufactured by forming a nonwoven fabric from a first fiber coated with a surface treatment agent by an air-through process. A lower layer web is manufactured by mixing the first fiber coated with a surface treatment agent and a second fiber coated with a hydrophilic surfactant, and forming the nonwoven fabric by an air-through process. The upper layer web and the lower layer web are superimposed to form a laminated web, and the first sheet 21 is manufactured by forming the laminated web by air-through process.
The first fiber, the second fiber, and the surface treatment agent used are as described above. The surface treatment agent is in a state in which the hydrophilic component, the oily component, and the polyhydric alcohol are uniformly mixed. The upper layer web and the lower layer web contain a surface treatment agent in which the hydrophilic component, the oily component, and the polyhydric alcohol are mixed. Here, the phrase "containing a surface treatment agent in a mixed state" does not mean that the surface treatment agent is obtained by applying a mixed liquid to the fiber layer as described above, but means that an interface exists between the hydrophilic component (hydrophilic surfactant and hydrophilic extract) and the oily component (hydrophobic extract) in the region of the fiber layer in which the surface treatment agent is contained. A preferred form of the "mixed state" is a state in which each component of the surface treatment agent exists uniformly dispersed, but is not limited to this. It is sufficient that the region with a high hydrophilic component/oil component ratio and the region with a high oily component/hydrophilic component ratio each exist without an interface, and there is no case in which the hydrophilic component does not exist or the oily component does not exist in each region. Here, the presence or absence of an "interface" can be determined by observing a cross section obtained by cutting the topsheet 1 in the vertical or horizontal direction at an appropriate magnification using an optical microscope or the like.
The multilayer top sheet having irregularities (top sheet 2 in this embodiment) can be manufactured according to conventional methods, but typically can be produced by overlapping and joining a first sheet having irregularities and a flat second sheet in accordance with JP 2004-174234 A.

Here, an example has been given of manufacturing the first sheet 21 in which fibers coated with a surface treatment agent are made into a nonwoven fabric, but after the fibers coated with a hydrophilic surfactant are made into a nonwoven fabric, a mixture of components of the surface treatment agent excluding the hydrophilic surfactant may be applied.
For example, a first fiber coated with a hydrophilic surfactant is made into a nonwoven fabric by an air-through method, and then a mixture of a hydrophobic extract such as argan oil, a polyhydric alcohol such as 1,3-butylene glycol, and a hydrophilic extract such as peach leaf extract is, for example, spray-coated onto the nonwoven fabric, and the mixture is left to stand for a long period of time to allow each component of the surface treatment agent to permeate the nonwoven fabric, thereby producing an upper layer web.
Next, the first fibers and the second fibers coated with a hydrophilic surfactant are mixed and made into a nonwoven fabric by an air-through method, and then a mixture of a hydrophobic extract such as argan oil, a polyhydric alcohol such as 1,3-butylene glycol, and a hydrophilic extract such as peach leaf extract is, for example, spray-coated onto the fabric and left for a predetermined time (for example, 5 hours at room temperature) to allow each component of the surface treatment agent to permeate the sheet, thereby producing a lower layer web.
In this way, a mixture of a polyhydric alcohol, a hydrophobic extract as an oily component, and a hydrophilic extract as a hydrophilic component is applied to a nonwoven fabric made of fibers coated with a hydrophilic surfactant, and the mixture is left for a predetermined time, so that the hydrophilic extract, hydrophobic extract, and polyhydric alcohol can be almost completely distributed in the nonwoven fabric. The nonwoven fabric thus produced has almost the same effect as a nonwoven fabric produced using fibers coated with a surface treatment agent consisting of a mixture of a hydrophilic surfactant and a hydrophilic extract as hydrophilic components, a hydrophobic extract, and a polyhydric alcohol, and even in such a state, the surface treatment agent contains a mixture of a hydrophilic component, an oily component, and a polyhydric alcohol. By using the nonwoven fabric thus produced as a top sheet, a top sheet can be obtained that has a good liquid absorption property and leaves little liquid remaining on the sheet, with a good balance between the ease of liquid spreading in the nonwoven fabric and the liquid drainage speed.

As described above, by containing a mixture of a hydrophilic component, an oily component, and a polyhydric alcohol in the fiber layer that constitutes the skin side of the diaper top sheet that contacts the wearer's skin, it is possible to create a top sheet that has a good balance between the ease of liquid spreading and the speed at which liquid drains off. This reduces the amount of liquid remaining on the top sheet when the diaper is worn, providing a comfortable fit for the wearer.

<Additional explanation>
[Method for measuring the amount of surface treatment agent (skin care agent) per unit area]
A method for measuring the amount per unit area of the skin care agent contained in the upper layer and the lower layer will be described.
After separating the first sheet and the second sheet from the top sheet 2, the first sheet was further separated into an upper layer and a lower layer, and samples of 50 mm in the vertical direction × 50 mm in the horizontal direction were cut out from each of the upper layer and lower layer, and the area of the samples was calculated. The planar area of the sample cut out from the almost flat lower layer was 2500 ^mm2 . In calculating the planar area of the upper layer having a plurality of convex portions, the cross section was observed at a magnification (for example, 150 to 500 times magnification) using a scanning electron microscope (for example, JCM-5100 (product name) manufactured by JEOL Ltd.), and the unevenness dimensions were measured from the cross-sectional image, and the area of the uneven surface of the upper layer was calculated based on this.
The sample is placed in a container with a small opening at the bottom. Then, the fiber is held down with a lid, the fiber is pushed to the bottom of the container, and the lid is removed. 10 cc of ether or 10 cc of a mixed solution of ethanol/methanol (volume ratio 1:1) is added thereto, and the mixture is left to stand for 10 minutes. Ether is a solvent mainly for the purpose of extracting oily components, and the mixed solvent of ethanol/methanol is a solvent for the purpose of extracting hydrophilic components and polyhydric alcohols. Then, the lid is placed again, and the fiber containing the solution is strongly pressed against the fiber to squeeze out the liquid (ether or ethanol/methanol component) contained in the fiber, and the squeezed liquid is placed in a weighing dish. Then, the weighing dish is heated to remove the solvent, and the weight of this weighing dish is measured, and the amount of the skin care agent is measured from the difference with the weight of the original weighing dish before the liquid was added. The amount of the skin care agent in the three samples is measured, and the average of the amounts is taken as the amount of the attached skin care agent.
The amount of skin care agent per unit area was calculated from the calculated area and the applied amount of skin care agent.
In addition, since oily components may be extracted into the ethanol/methanol extraction solvent, if all of the oily components contained in each fiber are extracted with the ethanol/methanol extraction solvent, extraction with ether is not necessary. If the hydrophilic components, oily components, and polyhydric alcohols are all extracted with ethanol/methanol, this means that each component has polarity, but if the hydrophilic components and oily components are skin care agents, this is advantageous in terms of affinity with the wearer's skin surface, and is therefore preferred.

The presence of first and second fibers having different surface treatment agent contents in the topsheet can be confirmed by the difference in the contact angle of the fibers due to the difference in the surface treatment agent content. Specifically, this is confirmed by taking out a plurality of fibers from the topsheet to be measured and measuring the contact angle of each fiber. The contact angle is measured by the following contact angle measurement method.
In addition, when the first fiber and the second fiber have different core-sheath ratios or different finenesses, the difference in core-sheath ratios or finenesses can be confirmed by observing the fiber cross sections with an electron microscope (SEM) or an optical microscope. Therefore, in such cases, by taking out a plurality of fibers having different core-sheath ratios or different finenesses and measuring the contact angles thereof, it can be confirmed that the first fiber and the second fiber have different surface treatment agent contents.
The contact angle was measured as follows. A medium-magnification zoom lens (with illumination ring) was used on a Keyence microscope VH-8000 in a state where it was inclined at 90°, and the measurement was performed under the condition of 500x magnification. The measurement sample was a surface sheet cut to a size of 150 mm in the vertical direction x 70 mm in the horizontal direction. The measurement environment was 20°C/50% RH, and the measurement sample was set on the measurement stage with the measurement surface facing up so that it could be observed from the CD direction of the web (nonwoven fabric). Next, 2 μl of ion-exchanged water was attached to the set measurement sample with a micropipette, and an image was captured within 5 seconds of attachment (preferably 2 to 3 seconds). The reason why the image needs to be captured in a short time after attachment is that the attached water droplets are evaporated by the light emitted from the measurement unit of the microscope and to prevent the contact angle from changing due to the surfactant. The contact angles of 10 observation results where both ends or one end of the water droplet were clearly focused were measured, and the average value of these was taken as the "contact angle". The contact angle is measured by drawing a tangent line between the water droplet and the fiber on the image or printed photograph and then using image analysis or a protractor.

<Other configuration examples>
Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, a disposable diaper is shown as an example of an absorbent article, but the absorbent article is not limited thereto. The absorbent article of the present invention may be, for example, a urine pad, a panty liner, a sanitary napkin, etc. Absorbent articles are generally configured to have a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retentive absorbent interposed between the two sheets.

In the above embodiment, the second fibers constituting a part of the lower layer of the first sheet contain only a hydrophilic surfactant, but the second fibers may be configured to contain a surface treatment agent consisting of a mixture of a hydrophilic surfactant, a hydrophilic extract, a hydrophobic extract, and a polyhydric alcohol.

In the above embodiment, the upper and lower layers of the first sheet have the same fiber fineness, but they may be different. For example, the fiber fineness of the upper layer may be finer than the fiber fineness of the lower layer. This increases the contact area between the hydrophobic extract and the hydrophilic extract and the skin.

In the above embodiment, the lower layer constituting the first sheet is configured to include first and second fibers having a sheath-core structure with different core/sheath ratios, but this is not limited to the above. The fibers included in at least one of the upper and lower layers may include at least two types of sheath-core structure fibers with different core/sheath ratios. Even in such a configuration, the inclusion of fibers with a higher core/sheath ratio can reduce uneven distribution of the surface treatment agent at the fusion point and reduce friction with the skin.

In the above embodiment, the top sheet has a laminated structure of two layers, that is, a first sheet made of a fiber layer having a plurality of protrusions and a second sheet that is substantially flat, which are superimposed on each other, but the top sheet is not limited to this. The top sheet may be composed of only the first sheet made of a single fiber layer having a plurality of protrusions.
In the above embodiment, the first sheet has a laminated structure including an upper layer and a lower layer, but it may be configured as a single layer.
The effects of the present invention can be achieved even if the top sheet does not have any irregularities and the skin side is flat.
As described above, the absorbent article is not limited to a laminated structure, etc., as long as the fiber layer constituting the skin side of the top sheet of the absorbent article contains a surface treatment agent in a state in which the hydrophilic component, the oily component and the polyhydric alcohol are mixed.

In addition, in the above embodiment, the hydrophilic component and the oily component are examples of skin care agents, but at least one of the hydrophilic component, the oily component, and the polyhydric alcohol contained in the surface treatment agent may be a skin care agent.

＜1＞
An absorbent article comprising a top sheet having a fiber layer positioned on the skin side of a wearer,
The absorbent article, wherein the fiber layer contains a surface treatment agent in a mixed state of a hydrophilic component, an oily component, and a polyhydric alcohol.
＜2＞
The absorbent article according to <1>, wherein the oil component contains an unsaturated fatty acid or an unsaturated fatty acid compound.
＜3＞
The absorbent article according to <1> or <2>, wherein the polyhydric alcohol has 2 to 4 carbon atoms.
＜4＞
The absorbent article according to any one of <1> to <3>, wherein the fiber layer has a laminated structure including an upper layer and a lower layer, and each of the upper layer and the lower layer includes a fiber containing the surface treatment agent.
＜5＞
The absorbent article according to <4>, wherein the lower layer includes first fibers having a relatively high content of the surface treatment agent and second fibers having a relatively low content of the surface treatment agent, and these fibers are fused to each other.
＜6＞
The absorbent article according to <4> or <5>, wherein the fibers contained in at least one of the upper layer and the lower layer include at least two types of core-sheath structure fibers having different core/sheath ratios.
＜７＞
At least one of the hydrophilic component, the oily component, and the polyhydric alcohol is a skin care agent, and the skin care agent is contained in a larger amount per unit area in the upper layer than in the lower layer.
＜8＞
The absorbent article according to any one of <1> to <7>, wherein the hydrophilic component contains a hydrophilic surfactant.
＜9＞
The absorbent article according to <8>, wherein the hydrophilic surfactant is a solid or semi-solid at 36°C.
＜10＞
The absorbent article according to <9>, wherein the hydrophilic component contains a hydrophilic plant extract.
<11>
The absorbent article according to any one of <1> to <10>, wherein the top sheet includes a first sheet made of the fiber layer and a second sheet superimposed on the first sheet, the first sheet and the second sheet are partially fixed to each other, and the first sheet has a plurality of convex portions formed by portions that are not fixed to the second sheet.
＜12＞
The absorbent article according to any one of <1> to <11>, wherein the surface treatment agent is a mixed liquid containing three components: the hydrophilic component, the oily component, and the polyhydric alcohol.
＜13＞
The absorbent article according to any one of <1> to <11>, wherein the three components of the hydrophilic component, the oily component and the polyhydric alcohol are present in a mixed state on or inside the fibers constituting the fiber layer.
＜14＞
The absorbent article according to any one of <1> to <13>, wherein the oil component and the polyhydric alcohol are liquid at 36°C.
＜15＞
The absorbent article according to any one of <1> to <14>, wherein the hydrophilic component contains a plant extract, and the plant extract is dissolved in a polyhydric alcohol.
＜16＞
The absorbent article according to any one of <1> to <15>, wherein the amount of the hydrophilic component dissolved in 1 L of ion-exchanged water is 1 g or more, preferably 5 g or more.
＜１７＞
The absorbent article according to any one of <1> to <16>, wherein the amount of the oily component dissolved in 1 L of ion-exchanged water is less than 1 g, preferably 0.1 g or less.
＜18＞
The absorbent article according to any one of <1> to <17>, wherein in the region of the fiber layer containing the surface treatment agent, no interface exists between the hydrophilic component and the oily component. <19>
The absorbent article according to <18>, wherein the hydrophilic component, the polyhydric alcohol and the oily component are uniformly dispersed.
＜20＞
The absorbent article according to <18>, comprising the hydrophilic component and the oily component, wherein a region in which the ratio of the hydrophilic component is high relative to the oily component and a region in which the ratio of the oily component is high relative to the hydrophilic component are present without having an interface.
＜21＞
The absorbent article according to any one of <1> to <20>, wherein the hydrophilic component includes at least one of peach leaf extract, hamamelis extract, and bamboo leaf extract.
＜22＞
The absorbent article according to any one of <1> to <21>, wherein the oil component contains an unsaturated fatty acid or an unsaturated fatty acid glyceride.
＜23＞
The absorbent article according to <22>, wherein the unsaturated fatty acid glyceride includes a monoester, a diester, or a triester of a fatty acid having 12 to 30 carbon atoms and containing 1 to 6 unsaturated bonds and glycerin.
＜24＞
The absorbent article according to <22>, wherein the oily component containing an unsaturated fatty acid is argan oil or shea butter.
＜25＞
The oily component and the hydrophilic component are skin care agents, and are all extracted into a mixed solvent of ethanol/methanol at a volume ratio of 1:1. The absorbent article according to any one of <1> to <24>.

<Example>
The present invention will be further described below with reference to examples, but the scope of the present invention is not limited to these examples.

Example 1
The nonwoven fabric used was an air-through nonwoven fabric made of fibers with a core-sheath structure (core-sheath ratio 50% by mass:50% by mass, fineness 2.3 dtex) in which the core was made of polyethylene terephthalate and the sheath was made of polyethylene.
The fibers coated with the fiber treatment composition containing a hydrophilic surfactant were made into a nonwoven fabric, and a nonwoven fabric was obtained with 0.35% by mass of the fiber treatment composition attached thereto. The nonwoven fabric was a single layer with a smooth surface. The nonwoven fabric was cut into a size of 10 cm x 10 cm, and a treatment liquid of an ethanol solution or aqueous solution containing 1,3-butylene glycol, peach leaf extract, and argan oil was applied to the nonwoven fabric, and the treatment liquid was allowed to permeate the nonwoven fabric. The nonwoven fabric was then left to dry for 5 hours at room temperature of 22°C and humidity of 65 RH%, to obtain the nonwoven fabric of Example 1. The amounts of the components attached to the nonwoven fabric of Example 1 were 70.397% by mass of hydrophilic surfactant, 0.603% by mass of peach leaf extract, 28.396% by mass of 1,3-butylene glycol, and 0.603% by mass of argan oil.
The fibers of the nonwoven fabric of Example 1 contain a mixture of hydrophilic components, that is, a hydrophilic surfactant and peach leaf extract, an oily component, argan oil, and a polyhydric alcohol, that is, 1,3-butylene glycol.
The composition of each component attached to the nonwoven fabric after treatment was calculated from the amount of treatment liquid attached to the fiber. The amount of treatment liquid attached was obtained from the weight difference between the nonwoven fabric immediately after treatment and before treatment. The composition was measured in the same manner in each of the following examples and comparative examples.
In each of the Examples and Comparative Examples, the concentration and composition of the treatment solution to be applied to the nonwoven fabric were adjusted so that different components were applied to the nonwoven fabric after treatment.
The fiber treatment composition had the following composition.
Alkyl phosphate potassium salt (Kao Corporation's Gripper 4131 neutralized with potassium hydroxide) 30% by mass
Alkyl (stearyl) betaine (Amphitol 86B, manufactured by Kao Corporation) 15% by mass
Polyoxyethylene (number of moles added: 2) stearylamide (Amizol SDE, manufactured by Kawaken Fine Chemicals) 30% by mass
Polyoxyethylene, polyoxypropylene modified silicone (X-22-4515, HLB: 5, manufactured by Shin-Etsu Chemical Co., Ltd.) 25% by mass

(Examples 2 to 8)
Samples of Examples 2 to 8 were obtained in the same manner as in Example 1, except that the contents of the fiber treatment composition, peach leaf extract, 1,3-butylene glycol and argan oil were changed as shown in Table 1.

(Comparative Example 1 to Comparative Example 4)
Samples of Comparative Example 1 to Comparative Example 4 were obtained in the same manner as in Example 1, except that the amounts of the fiber treatment composition, peach leaf extract, 1,3-butylene glycol and argan oil applied were changed as shown in Table 2.

(Comparative Example 5)
A nonwoven fabric cut to a size of 10 cm x 10 cm to which 0.35% by mass of the same fiber treatment composition as in Example 1 was attached was applied with a treatment liquid of an ethanol solution or aqueous solution containing 1,3-butylene glycol and peach leaf extract, the treatment liquid was allowed to permeate the nonwoven fabric, and the fabric was then left to dry for 5 hours. An ethanol solution of argan oil was then applied to this dried nonwoven fabric, and the fabric was left to dry for several minutes, to obtain a nonwoven fabric of Comparative Example 5. The amounts of each component attached to the nonwoven fabric of Comparative Example 5 were 69.531% by mass of the fiber treatment composition, 0.6190% by mass of the peach leaf extract, 29.127% by mass of 1,3-butylene glycol, and 0.722% by mass of argan oil.
The fibers of the nonwoven fabric of Comparative Example 5 are manufactured by adhering a mixture of a hydrophilic component and a polyhydric alcohol, and then adhering argan oil, which is different from the manufacturing process of the Examples, which are manufactured using a mixture of a hydrophilic component, an oily component, and a polyhydric alcohol as a surface treatment agent. Due to this manufacturing method, the argan oil is not mixed with the hydrophilic component and the polyhydric alcohol mixture.

[Evaluation method]
(Liquid cut-off evaluation)
The liquid drainage speed was measured for the nonwoven fabrics of Examples 1 to 8 and Comparative Examples 1 to 5 by the following method. The nonwoven fabric to be measured was placed on two Kimwipes (registered trademark) (manufactured by Nippon Paper Crecia Co., Ltd., S-200). 0.02 ml of a liquid obtained by mixing artificial urine and glycerin at a ratio of 5:1 was dropped onto the nonwoven fabric with a pipette, and the behavior of the liquid was observed using a digital microscope VHX-5000 manufactured by Keyence Corporation. The time from when the liquid was dropped until the liquid spread between the fibers to form a liquid film and the liquid film broke and disappeared was measured. The measured time was used as the liquid drainage speed to evaluate the liquid drainage. The shorter the time, the better the liquid drainage.
The artificial urine was obtained by mixing 1.940% by mass of urea, 0.795% by mass of sodium chloride, 0.111% by mass of magnesium sulfate, 0.062% by mass of calcium chloride, 0.198% by mass of potassium sulfate, 0.005% by mass of Red No. 2 (dye), water (96.882% by mass) and polyoxyethylene lauryl ether (0.007% by mass), and had a surface tension adjusted to 53±1 dyne/cm (23° C.).

(Liquid wettability evaluation)
The contact angle of the nonwoven fabrics of Examples 1 to 8 and Comparative Examples 1 to 5 was measured by the following method to evaluate the liquid wettability. A drop of artificial urine was dropped onto the nonwoven fabric with a pipette, and an image of the side surface was taken with a microscope, and the contact angle was measured using the image. The smaller the contact angle, the easier the liquid spreads.

[result]
The components of the treatment agent used for the nonwoven fabric in each Example and the above evaluation results are shown in Table 1. The components of the treatment agent used for the nonwoven fabric in each Comparative Example and the above evaluation results are shown in Table 2. In the table, BG stands for 1,3-butylene glycol. AO stands for argan oil. In the table, in the liquid drainage evaluation, a liquid drainage speed (seconds) of less than 65 seconds was rated A, 65 to 75 seconds was rated B, and more than 75 seconds was rated C. In the liquid wettability evaluation, a liquid wettability (°) of less than 70° was rated A, 70 to 90° was rated B, and more than 90° was rated C.

As shown in Tables 1 and 2, it was confirmed that by producing a nonwoven fabric using a surface treatment agent that is a mixture of a hydrophilic component, an oily component, and a polyhydric alcohol, it is possible to produce a nonwoven fabric that has a good balance between the ease of liquid spreading and the speed at which liquid is cut off.

It was found that in all of Examples 1 to 8, the liquid cutting speed was improved compared to Comparative Example 1, and the ease of liquid spreading was equal to or greater than that of Comparative Example 1.
In the nonwoven fabrics of Comparative Example 2, which contained a hydrophilic component and a polyhydric alcohol but no oily component, and Comparative Example 4, which contained a hydrophilic surfactant and a polyhydric alcohol but no oily component, the ease of liquid spreading was improved compared to Comparative Example 1, but the liquid drainage speed tended to be slow, similar to Comparative Example 1.
In addition, in the case of the nonwoven fabric of Comparative Example 3, which contained a fiber treatment agent composition containing a hydrophilic surfactant (hydrophilic component) and an oily component but did not contain a polyhydric alcohol, the liquid drainage speed was improved compared to Comparative Example 1, but it was found that the liquid tended to spread more difficultly than in Comparative Example 1.
The nonwoven fabric of Comparative Example 5 was produced by treating the nonwoven fabric with a treatment agent in which a polyhydric alcohol and a hydrophilic component were added to a fiber treatment composition containing a hydrophilic surfactant (hydrophilic component) as a base, and then attaching an oily component, in which the oily component was not mixed with other components. The nonwoven fabric of Comparative Example 5 had a higher liquid drainage speed than Comparative Example 1, but was found to have a tendency to be more difficult to spread liquid than Comparative Example 1. That is, as shown in Examples 1 to 8, it was confirmed that a nonwoven fabric having a good balance between the ease of liquid spreading and the liquid drainage speed can be produced by producing a nonwoven fabric using a mixed liquid of a hydrophilic component, an oily component, and a polyhydric alcohol as a surface treatment agent.

1... Disposable diapers (absorbent articles)
2: Surface sheet 21: First sheet (fiber layer)

Claims (7)

An absorbent article comprising a top sheet having a fiber layer positioned on the skin side of a wearer,
the fiber layer contains a surface treatment agent in a mixed state of a hydrophilic component, an oily component, and a polyhydric alcohol ;
The hydrophilic component includes a hydrophilic extract, and the oily component includes a hydrophobic extract,
The fiber layer has a laminated structure including an upper layer and a lower layer,
the upper layer is composed of first fibers containing the surface treatment agent,
the lower layer is configured by mixing a first fiber containing the surface treatment agent and a second fiber coated with only a hydrophilic surfactant,
The first fiber and the second fiber are core-sheath fibers having different core/sheath ratios,
The core/sheath ratio of the second fibers is higher than the core/sheath ratio of the first fibers.
Absorbent articles. The absorbent article according to claim 1 , wherein the oily component comprises an unsaturated fatty acid or an unsaturated fatty acid compound. The absorbent article according to claim 1 or 2, wherein the polyhydric alcohol has 2 to 4 carbon atoms. The hydrophilic component includes a hydrophilic surfactant and a plant extract as the hydrophilic extract,
the oil component and the polyhydric alcohol are liquid at 36°C;
The hydrophilic surfactant is a solid or semi-solid at 36° C.
The absorbent article according to any one of claims 1 to 3. The absorbent article according to claim 1 , wherein the lower layer is formed by fusing the first fibers and the second fibers to each other. 6. The absorbent article according to claim 1, wherein at least one of the hydrophilic component, the oily component and the polyhydric alcohol is a skin care agent, and the skin care agent is contained in a larger amount per unit area in the upper layer than in the lower layer. the top sheet includes a first sheet made of the fiber layer and a second sheet superimposed on the first sheet,
The absorbent article according to claim 1 , wherein the first sheet and the second sheet are partially fixed to each other , and the first sheet has a plurality of convex portions formed by portions that are not fixed to the second sheet.

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