Nonwoven fabric for sanitary item

Abstract

To provide a nonwoven fabric for sanitary item having hydrophilicity, high in antibacterial property, further, reduced in liquid return when used as a surface sheet of, for example, an absorbent article, and high in dry property.SOLUTION: A nonwoven fabric for sanitary item containing the following (A) components and one or more selected from (B) components, (C) components and (D) components. (A) Component: Alkyl phosphate salt or polyoxyalkylene alkyl ether phosphate salt of group 11 or group 12 element of the periodic table, (B) Component: Nonionic surfactant, (C) Component: Anionic surfactant, (D) Component: Betaine surfactant.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a nonwoven fabric for sanitary articles. [Background technology]

[0002] Nonwoven fabrics used in sanitary articles such as disposable diapers and sanitary napkins are often desired to have antibacterial properties in addition to hydrophilicity. From this perspective, Patent Document 1 proposes the use of nonwoven fabrics for diapers and the like, which are formed by molding a composition obtained by mixing a nonionic surfactant and a zinc oxide-based antibacterial agent with polyolefin using a spunbonding method or a meltblown method. The nonwoven fabric described in the same document also shows excellent antibacterial properties for a long period of time and is also hydrophilic.

[0003] Patent Document 2 proposes the use of a nonwoven fabric, the constituent fibers of which contain zinc oxide and to which a fiber treatment agent containing a surfactant selected from an alkylene oxide-addition type nonionic surfactant and a polyhydric alcohol type nonionic surfactant is attached, for diapers and napkins. The nonwoven fabric described in this document is also described as having antibacterial properties and hydrophilic properties. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-249615 A [Patent Document 2] JP 2007-107144 A Summary of the Invention [Problem to be solved by the invention]

[0005] Although the nonwoven fabrics described in Patent Documents 1 and 2 both have antibacterial properties and hydrophilicity, there is a demand for nonwoven fabrics with even higher antibacterial properties. In addition to antibacterial properties and hydrophilicity, there is also a demand for nonwoven fabrics with high dryness and reduced liquid return when used, for example, as a top sheet of an absorbent article.

[0006] Therefore, an object of the present invention is to provide a nonwoven fabric for hygienic articles that is hydrophilic, has high antibacterial properties, and further has high dryness and reduced liquid return when used, for example, as a top sheet of an absorbent article. [Means for solving the problem]

[0007] The present invention relates to a nonwoven fabric for sanitary goods, which contains the following component (A) and one or more components selected from the group consisting of component (B), component (C) and component (D). Component (A): Alkyl phosphate ester salt or polyoxyalkylene alkyl ether phosphate ester salt of an element of Group 11 or 12 of the periodic table (B) Component: Nonionic surfactant Component (C): Anionic surfactant (D) Component: Betaine type surfactant Effect of the Invention

[0008] According to the present invention, a nonwoven fabric for sanitary goods having high antibacterial and hydrophilic properties is provided. Furthermore, when the nonwoven fabric of the present invention is used as, for example, a top sheet of an absorbent article, it has little liquid return and excellent dryness. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view illustrating a nonwoven fabric according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view illustrating a nonwoven fabric according to another embodiment of the present invention. [Diagram 3] FIG. 3 is a perspective view illustrating a nonwoven fabric according to another embodiment of the present invention. [Figure 4]4(a) and 4(b) are perspective views that typically show other embodiments of the nonwoven fabric of the present invention. [Diagram 5] FIG. 5 is a perspective view that typically illustrates another embodiment of the nonwoven fabric of the present invention. [Figure 6] FIG. 6 is a perspective view diagrammatically illustrating another embodiment of the nonwoven fabric of the present invention. [Figure 7] FIG. 7 is a plan view diagrammatically showing still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below based on its preferred embodiments. The nonwoven fabric of the present invention contains the following component (A) and one or more components selected from the group consisting of component (B), component (C) and component (D). Component (A): Alkyl phosphate ester salt or polyoxyalkylene alkyl ether phosphate ester salt of an element of Group 11 or 12 of the periodic table (B) Component: Nonionic surfactant Component (C): Anionic surfactant (D) Component: Betaine type surfactant By containing such a component, the nonwoven fabric of the present invention has hydrophilicity and high antibacterial properties. A nonwoven fabric having such properties is suitable as a constituent material for sanitary articles. In particular, it is preferable to use the nonwoven fabric of the present invention as a part of a sanitary article where antibacterial properties and hydrophilicity are required, such as a top sheet of an absorbent article or an inner nonwoven fabric in an exterior sheet composed of an outer nonwoven fabric and an inner nonwoven fabric, from the viewpoint of making the most of the characteristics of the nonwoven fabric. In particular, when the nonwoven fabric of the present invention is used as a top sheet of an absorbent article, it has little liquid return and excellent dryness. In this specification, a composition containing the component (A) and one or more selected from the components (B) to (D) is also referred to as a "fiber treatment agent."

[0011] The alkyl phosphate ester salt of component (A) used in the present invention has the general formula RPO3M1 X Polyoxyalkylene alkyl ether phosphate salts are represented by the general formula RO(AO) n -PO3M 1 X In the formula, R represents a linear or branched alkyl group, AO represents an oxyalkylene group, and n represents the average number of moles of the oxyalkylene group added. M 1 represents a metal element. X represents a metal element M 1 represents a number according to the valence of. The alkyl phosphate salt or polyoxyalkylene alkyl ether phosphate salt of component (A) is a metal salt of an element of Group 11 or 12 of the periodic table. 1 is preferably an element of Group 11 or 12 of the periodic table. 1 One type may be used alone, or two or more types may be used in combination.

[0012] From the viewpoint of antibacterial properties, the above-mentioned metal element M 1 More preferably, the metal element M is an element of Group 11 or 12 of the periodic table and of Period 4 or Period 5. 1 is more preferably at least one selected from the group consisting of zinc, silver and copper, and even more preferably zinc.

[0013] From the viewpoints of imparting sufficient antibacterial properties to the nonwoven fabric and suppressing liquid return when the nonwoven fabric of the present invention is used, for example, as a topsheet of an absorbent article, the chain length of the alkyl group in the alkyl phosphate salt or polyoxyalkylene alkyl ether phosphate salt is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more. In addition, from the viewpoints of not excessively decreasing the hydrophilicity of the nonwoven fabric, the chain length of the alkyl group is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. The oxyalkylene group AO in the polyoxyalkylene alkyl ether phosphate salt is preferably at least one selected from the group consisting of an oxyethylene group, an oxypropylene group, and an oxybutylene group, from the viewpoint of imparting sufficient antibacterial property and hydrophobicity to the nonwoven fabric, and is more preferably an oxyethylene group. The average number of moles n of oxyalkylene groups added in the polyoxyalkylene alkyl ether phosphate salt is preferably 1 or more, from the viewpoint of imparting sufficient antibacterial properties and hydrophobicity to the nonwoven fabric. Also, from the viewpoint of ensuring the hydrophobicity of the nonwoven fabric, the average number of moles n added is preferably 30 or less, more preferably 20 or less, even more preferably 15 or less, even more preferably 10 or less, and even more preferably 5 or less.

[0014] The nonwoven fabric of the present invention is RPO4M 1 X (M 1 represents an element of Group 11 or 12 of the periodic table. n -PO3M 1 X (M 1 represents an element of Group 11 or 12 of the periodic table.) The nonwoven fabric of the present invention may contain one or more of the polyoxyalkylene alkyl ether phosphate salts (A) represented by the formula (A). In addition to the (A) component, the nonwoven fabric of the present invention may contain RPO4M 2 Y or RO-(AO) n -PO3M 2 Y (M 2 represents an alkali metal or an alkaline earth metal; Y represents a metal element M 2 The number of alkyl phosphate salts or polyoxyalkylene alkyl ether phosphate salts represented by the formula (1) may additionally be contained. For example, RPO4K2 (potassium alkyl phosphate salt) or RO-(AO) n It may contain -PO3K2 (potassium polyoxyalkylene alkyl phosphate ester).

[0015] From the viewpoint of imparting sufficient antibacterial properties to the nonwoven fabric and suppressing liquid return when the nonwoven fabric of the present invention is used, for example, as a top sheet of an absorbent article, the ratio of the fiber treatment agent (A) component contained in the nonwoven fabric of the present invention is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, based on the mass of the nonwoven fabric to which the fiber treatment agent is attached. Also, from the viewpoint of preventing a loss of liquid permeability due to water repellency, the ratio of the fiber treatment agent (A) component contained in the nonwoven fabric is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less, based on the mass of the nonwoven fabric to which the fiber treatment agent is attached. The proportion of the alkyl phosphate salt or polyoxyalkylene alkyl ether phosphate salt contained in the nonwoven fabric can be confirmed by analysis using solid-state nuclear magnetic resonance (NMR) or X-ray photoelectron spectroscopy (XPS), or by immersing the nonwoven fabric in a solvent or the like and applying a physical stimulus such as ultrasound to dissolve the alkyl phosphate salt or polyoxyalkylene alkyl ether phosphate salt, and then analyzing the resultant solution using a nuclear magnetic resonance (NMR) device or the like. In addition, when it is necessary to prepare a nonwoven fabric to serve as a reference for the measurement, which does not have any alkyl phosphate ester salt or polyoxyalkylene alkyl ether phosphate ester salt attached thereto, the resin of the nonwoven fabric is identified using an infrared spectrophotometer (FT-IR) or the like, and the reference nonwoven fabric is prepared and used.

[0016] Examples of the nonionic surfactant of the component (B) used in the present invention include polyhydric alcohol fatty acid esters such as glycerin fatty acid esters, poly (preferably n = 2 to 10) glycerin fatty acid esters, sorbitan fatty acid esters (all of which preferably have a fatty acid having 8 to 60 carbon atoms), alkylene oxide adducts of the above polyhydric alcohol fatty acid esters (preferably the number of moles added is 2 to 60 moles), polyoxyalkylene (number of moles added is 2 to 60) alkyl (number of carbon atoms is 8 to 22) amides, polyoxyalkylene (number of moles added is 2 to 60) alkyl (number of moles added is 8 to 22) ethers, polyoxyalkylene (number of moles added is 2 to 60) alkyl (number of moles added is 8 to 22) phenyl ethers, polyoxyethylene polyoxypropylene ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyalkylene-modified silicones, amino-modified silicones, and alkyl alkanolamides. Among these, from the viewpoint of achieving both hydrophilicity and nonwoven fabric processability, it is preferable to use polyoxyalkylene (number of moles added: 2 to 60) alkyl (number of carbon atoms: 8 to 22) ether, polyoxyalkylene (number of moles added: 2 to 60) alkyl (number of carbon atoms: 8 to 22) phenyl ether, and alkylene oxide adducts of polyhydric alcohol fatty acid esters.

[0017] Examples of the anionic surfactant of component (C) used in the present invention include alkyl sulfates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, polyoxyethylene alkyl ether sulfates, alkyl sulfonates, alkyl carboxylates, alkyl phosphates (excluding salts of elements of Groups 11 or 12 of the periodic table), alkyl diphenyl ether disulfonates, and alkyl sulfosuccinates. Of these, from the viewpoint of achieving both stabilization of card properties due to the antistatic effect and initial hydrophilicity, it is preferable to use alkyl phosphates (excluding salts of elements of Groups 11 or 12 of the periodic table) or alkyl sulfosuccinates.

[0018] Examples of the betaine surfactant of component (D) used in the present invention include carbobetaine, amidobetaine, sulfobetaine, hydroxysulfobetaine, amidosulfobetaine, phosphobetaine, and imidazolinium surfactants having an alkyl group, alkenyl group, or acyl group having a carbon number of 8 to 24. Of these, it is preferable to use a carbobetaine amphoteric surfactant, etc., from the viewpoint of enhancing durable hydrophilicity.

[0019] The total proportion of the (B) to (D) components contained in the nonwoven fabric of the present invention is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more, based on the total of the (A) to (D) components of the fiber treatment agent, from the viewpoint of imparting sufficient hydrophilicity to the nonwoven fabric. Also, from the viewpoint of suppressing liquid return when the nonwoven fabric of the present invention is used, for example, as a topsheet of an absorbent article, the total proportion of the (B) to (D) components contained in the nonwoven fabric is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 75% by mass or less, based on the total of the (A) to (D) components of the fiber treatment agent.

[0020] From the viewpoint of imparting antibacterial properties and hydrophilicity in a well-balanced manner to the nonwoven fabric, the proportion of the (A) component to the total of the (A), (B), (C) and (D) components contained in the nonwoven fabric of the present invention is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. The proportion of the (A) component is preferably 65% ​​by mass or less, more preferably 60% by mass or less, and even more preferably 55% by mass or less.

[0021] The nonwoven fabric of the present invention may contain only one or two of the (B) to (D) components as surfactants. It may also contain all three. From the viewpoint of achieving both nonwoven fabric processability, initial hydrophilicity, and durable hydrophilicity, it is preferable to contain all of the (B) to (D) components. From the viewpoint of imparting hydrophilicity and nonwoven fabric processability, the proportion of the (B) component is preferably 10% by mass to 50% by mass, and more preferably 15% by mass to 35% by mass, based on the total of the (A) to (D) components. From the viewpoint of initial hydrophilicity and cardability stabilization due to antistatic properties, the proportion of the (C) component is preferably 10% by mass to 50% by mass, and more preferably 15% by mass to 35% by mass, based on the total of the (A) to (D) components. From the viewpoint of imparting durable hydrophilicity, the proportion of the (D) component is preferably 10% by mass to 50% by mass, and more preferably 15% by mass to 35% by mass, based on the total of the (A) to (D) components. Furthermore, there is no limitation on the method for applying the fiber treatment agent to the nonwoven fabric. For example, any or all of the components (A) to (D) may be mixed in advance and then applied to the nonwoven fabric, or the components (A) to (D) may be applied to the nonwoven fabric in sequence in any order without being mixed.

[0022] Each component of the fiber treatment agent may be present independently on the surface of the fibers constituting the nonwoven fabric, may be present in the fibers, or may be present both on the surface of the fibers and in the fibers. Each component of the fiber treatment agent may be present independently over the entire area of ​​the nonwoven fabric, or may be present partially over the entire area of ​​the nonwoven fabric. In order to cause the fiber treating agent to be present on the surface of the fibers constituting the nonwoven fabric, for example, an aqueous dispersion containing the fiber treating agent may be applied to the nonwoven fabric, which is the raw material, and then the water may be removed. In order to make the fiber treating agent present in the fibers constituting the nonwoven fabric, for example, the fiber treating agent and the resin constituting the fibers are melt-kneaded, and the kneaded mixture is melt-spun.

[0023] By including one or more surfactants selected from the components (B) to (D) in the nonwoven fabric of the present invention, the hydrophilicity of the nonwoven fabric is increased. The degree of hydrophilicity can be expressed, for example, by the hydrophilicity ratio. The hydrophilicity ratio can be measured as follows. <Method of measuring hydrophilicity> A nonwoven fabric piece measuring 6 cm x 6 cm is cut out from the nonwoven fabric. Next, the nonwoven fabric piece is prepared in a state where the pleats and wrinkles of the nonwoven fabric piece are stretched out. Then, a cold spray is sprayed on Merrys (registered trademark) First Premium Tape (S size), a disposable diaper manufactured by Kao Corporation that was commercially available in June 2022, to solidify the adhesive and remove the top sheet, and the nonwoven fabric piece is attached in place of the removed top sheet. 0.1 g of ion-exchanged water is placed on the surface of the nonwoven fabric piece in 5 rows x 6 columns at 8 mm intervals, for a total of 30 droplets. Then, it is left to stand for 60 seconds. Then, the number of droplets that have been absorbed by the ion-exchanged water and migrated to the diaper side or the nonwoven fabric piece is defined as the number of droplets absorbed in 60 seconds (W1). The measured value of W1 is the average value of n = 3. Then, the droplet absorption rate (W2) is calculated based on the following formula, and this is defined as the hydrophilicity rate. The number of droplets absorbed in 60 seconds (W1) is determined by visually checking whether or not droplets are present on the nonwoven fabric. Hydrophilicity rate = Droplet absorption rate (W2) = (Number of droplets absorbed in 60 seconds (W1) / 30 (Number of droplets initially placed)) × 100

[0024] From the viewpoint of exhibiting sufficient hydrophilicity, the nonwoven fabric of the present invention preferably has a hydrophilicity of 40% or more, more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, and even more preferably 90% or more, as measured by the above method. Also, from the viewpoint of suppressing liquid return after absorbing liquid, the nonwoven fabric of the present invention preferably has a hydrophilicity of 100% or less, as measured by the above method.

[0025] The nonwoven fabric of the present invention may contain an antibacterial agent from the viewpoint of further enhancing the antibacterial properties of the nonwoven fabric. Examples of the antibacterial agent include organic antibacterial agents, metal oxides, and natural extracts. Examples of the organic antibacterial agent include quaternary ammonium salts. Examples of the metal oxides include silver oxide, copper oxide, and zinc oxide. Examples of the natural extracts include peppermint, tea tree, thyme thymol, oregano, rosemary, eucalyptus, argan oil, asarum, ginger, hibamata, and horse chestnut. Among these, metal oxides are preferred from the viewpoint of antibacterial properties, and zinc oxide is more preferred. When the nonwoven fabric of the present invention contains a metal oxide, from the viewpoints of antibacterial properties, spinnability as a fiber, shedding from the fiber, and feel when touching the skin, the average particle size of the metal oxide is preferably 0.2 μm to 2.0 μm, more preferably 0.3 μm to 1.5 μm, and even more preferably 0.4 μm to 1.2 μm. The average particle size of the metal oxide can be measured by taking cross-sectional photographs from five locations using a scanning electron microscope (SEM) or the like, approximating the cross-sectional shape to a circle, and averaging the images using image processing software such as WINROOF2018 (Mitani Shoji).

[0026] When the nonwoven fabric of the present invention contains a metal oxide, it is preferable that the metal oxide is kneaded into the fibers constituting the nonwoven fabric from the viewpoint of maintaining antibacterial properties over a long period of time. When the fibers constituting the nonwoven fabric are, for example, core-sheath type composite fibers, it is preferable that the metal oxide is present in the sheath part of the composite fibers from the viewpoint of effectively exhibiting antibacterial properties.

[0027] The ratio of the metal oxide contained in the nonwoven fabric of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, based on the mass of the nonwoven fabric containing the fiber treatment agent and the metal oxide, from the viewpoint of imparting sufficient antibacterial properties to the nonwoven fabric. The ratio of zinc oxide is preferably 3.0% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less, based on the mass of the nonwoven fabric containing the fiber treatment agent and the metal oxide, from the viewpoint of processability of the nonwoven fabric and prevention of facility contamination.

[0028] In the present invention, there is no particular limitation on the type of nonwoven fabric, and any nonwoven fabric known so far can be used. The length of the fibers constituting the nonwoven fabric may be long fibers (continuous filaments) or short fibers (staple fibers) depending on the manufacturing method of the nonwoven fabric. Of long and short fibers, nonwoven fabrics made of short fibers have a good texture and are therefore particularly suitable as a constituent material for sanitary goods. Whether the fibers constituting the nonwoven fabric are long fibers or short fibers, the fiber fineness is preferably 1.0 dtex or more and 5.0 dtex or less, more preferably 1.3 dtex or more and 3.8 dtex or less, and even more preferably 2.0 dtex or more and 3.3 dtex or less, from the viewpoint of improving the texture of the nonwoven fabric.

[0029] The type of fiber constituting the nonwoven fabric is not particularly limited, and fibers made of various thermoplastic resins having fiber-forming ability can be used. Specifically, fibers made of polyolefin resins such as polyethylene, polypropylene, and ethylene-α-olefin copolymers, fibers made of polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and fibers made of polyacrylic resins such as polyacrylic acid and polymethacrylic acid can be used. As the constituent fibers of the nonwoven fabric, multi-component fibers such as core-sheath type composite fibers and side-by-side type composite fibers containing the above-mentioned resins can also be used. The above fibers can be used alone or in combination of two or more. In particular, nonwoven fabrics containing core-sheath type composite fibers have a good texture and are therefore particularly suitable as constituent materials for sanitary goods. When a core-sheath type composite fiber is used as a constituent fiber of a nonwoven fabric, from the viewpoint of further improving the texture of the nonwoven fabric, it is preferable that the sheath is made of polyethylene and the core is made of polyethylene terephthalate. From the same viewpoint, it is also preferable that the sheath of the core-sheath type composite fiber is made of polyethylene and the core is made of polypropylene.

[0030] Examples of nonwoven fabrics include air-through nonwoven fabrics, spunbond nonwoven fabrics, spunlace nonwoven fabrics, needle-punched nonwoven fabrics, meltblown nonwoven fabrics, chemically bonded nonwoven fabrics, etc. In the present invention, these nonwoven fabrics may be used in a laminate of two or more layers. Among the various nonwoven fabrics mentioned above, the air-through nonwoven fabric, which is a nonwoven fabric manufactured using staple fibers as a raw material, has a good feel due to its manufacturing method and is therefore particularly suitable for use as a constituent material of sanitary goods.

[0031] In any of the above-mentioned cases, the basis weight of the nonwoven fabric is 10 g / m2 from the viewpoint of improving the texture of the nonwoven fabric. 2 More than 80g / m 2 It is preferable that the thickness is less than 13 g / m 2 More than 50g / m 2 More preferably, it is 15 g / m or less. 2 More than 30g / m 2 It is even more preferred that:

[0032] The nonwoven fabric may be of a single layer structure or a laminated structure of two or more layers. The surface of the nonwoven fabric may be flat, may have an uneven shape, or may be raised. Figures 1 to 7 show schematic diagrams of nonwoven fabrics having an uneven shape on at least one surface.

[0033] 1 has a first surface 10A and a second surface 10B located on the opposite side, and at least the first surface 10A has an uneven structure having a plurality of protrusions 13 protruding toward the first surface 10A and recesses 14 located between the protrusions 13. The second surface 10B is substantially flat. The nonwoven fabric 10 is composed of two layers, an upper layer 11A on the first surface 10A side and a lower layer 11B on the second surface 10B side. The upper layer 11A and the lower layer 11B are joined by embossing in the thickness direction. The embossed portions correspond to the recesses 14. The lower layer 11B is a layer in which the heat shrinkage of the heat shrinkable fiber is manifested. The upper layer 11A is a layer containing a non-heat shrinkable fiber. From the viewpoint of successfully forming a nonwoven fabric by applying heat, it is preferable that the non-heat shrinkable fiber is a non-heat shrinkable heat fusion fiber. Nonwoven fabric 10 can be manufactured, for example, by the materials and method described in JP 2002-187228 A. In this manufacturing method, for example, a laminate of upper layer 11A and lower layer 11B is embossed from the upper layer 11A side, and then heat is applied to heat-shrink the heat-shrinkable fibers contained in lower layer 11B. The shrinkage of the fibers causes deformation in which adjacent embossed portions are pulled together and the distance between them is reduced. This deformation causes the fibers contained in upper layer 11A to rise toward first surface 10A from the embossed portions as base points, forming protrusions 13.

[0034] The nonwoven fabric 20 shown in FIG. 2 has a two-layer structure having a hollow portion 21. Both of the two layers constituting the nonwoven fabric 20 contain thermoplastic fibers. The nonwoven fabric 20 has a joint portion 22 where a first nonwoven fabric 20A and a second nonwoven fabric 20B are partially heat-fused together. In a non-joint portion surrounded by a plurality of joint portions 22 (four in FIG. 2), the first nonwoven fabric 20A protrudes in a direction away from the second nonwoven fabric 20B to form a convex portion 23 having a hollow portion 21 therein. The joint portion 22 is a recess located between adjacent convex portions 23, 23, and together with the convex portion 23, forms an uneven structure on the first nonwoven fabric 20A side. The nonwoven fabric 20 can be manufactured by the materials and method described in, for example, JP 2004-174234 A. In this method, a first nonwoven fabric 20A is shaped to have projections and recesses by engaging a pair of projection-recess rolls, and then the first nonwoven fabric 20A and a second nonwoven fabric 20B are bonded together. From the viewpoint of shaping the first nonwoven fabric 20A by engaging a pair of projection-recess rolls, it is preferable that both the first nonwoven fabric 20A and the second nonwoven fabric 20B contain non-thermally extensible, non-thermally shrinkable heat-fusible fibers.

[0035] 3 has a single-layer structure having an uneven structure on each surface thereof. In the nonwoven fabric 30, first protruding portions 31 protruding toward the first surface 30A and second protruding portions 32 protruding toward the second surface 30B are arranged alternately and continuously in two different directions that intersect when the nonwoven fabric 30 is viewed in a plan view. The first protruding portion 31 and the second protruding portion 32 each have an open internal space on the opposite surface side, and these portions form recesses 33, 34 on that surface. As a result, the first surface 30A has an uneven structure having the first protruding portion 31 and the recesses 34. The second surface 30B has an uneven structure having the second protruding portion 32 and the recesses 33. The nonwoven fabric 30 has a wall portion 35 that connects the first protruding portion 31 and the second protruding portion 32. The wall portion 35 forms a wall surface of the internal space of each of the first protruding portion 31 and the second protruding portion 32, and has a ring-shaped structure in the planar direction. The nonwoven fabric 30 can be manufactured by the material and method described in, for example, JP 2012-136790 A. In this method, the fiber web is supported on a support and subjected to an air-through process in which hot air is treated in multiple stages while controlling the hot air temperature and air speed, to impart irregularities to the fiber web. As the support for imparting irregularities to the fiber web, it is preferable to use one having solid protrusions and openings. For example, the support described in JP 2012-149370 A can be used.

[0036] The nonwoven fabric 40 shown in Fig. 4(a) has a single-layer structure containing thermoplastic fibers. The nonwoven fabric 40 has a shape on the first surface 40A side in which semi-cylindrical convex portions 41 and concave portions 42 arranged along the side edges of the convex portions 41 are alternately arranged. Under the concave portions 42, concave portion bottom portions 43 made of nonwoven fabric fibers are arranged. The concave portion bottom portions 43 have a lower fiber density than the convex portions 41. In the nonwoven fabric 40, another fiber layer 45 may be partially laminated on the convex portions 41 as shown in Fig. 4(b). The nonwoven fabric 40 can be formed by blowing a fluid such as hot air onto the portions of the fiber web that will become the recesses 42 to move the fibers. This makes it possible to make the fiber density at the bottoms 43 of the recesses lower than that of the surrounding areas.

[0037] The nonwoven fabric 50 shown in Fig. 5 has a single layer structure. The nonwoven fabric 50 has alternately arranged protruding streaks 51 and recessed streaks 52 that extend in one direction. The nonwoven fabric 50 has an uneven structure on both sides. The uneven structure on one side and the uneven structure on the other side have complementary shapes. The nonwoven fabric 50 may be used alone, or may be joined with a flat fiber layer to form a laminated nonwoven fabric, or may be laminated with a fiber layer having an uneven structure and integrated along the uneven structure to form a laminated nonwoven fabric.

[0038] The nonwoven fabric 60 shown in Fig. 6 has a single layer structure. The nonwoven fabric 60 is made from heat-extensible fibers and contains the heat-extensible fibers after stretching. A first surface 60A of the nonwoven fabric 60 has an uneven structure. A second surface 60B located on the opposite side to the first surface 60A is substantially flat or has a smaller unevenness than the first surface 60A. The first surface 60A of the nonwoven fabric 60 has a plurality of protruding portions 61 and linear recessed portions 62 surrounding the protruding portions 61. The recessed portions 62 have press-bonded portions where the constituent fibers of the nonwoven fabric 60 are pressed or bonded. In this state, the heat-extensible fibers contained in the nonwoven fabric are in an elongated state. The protruding portions 61 are portions where the heat-extensible fibers are thermally elongated and protrude toward the first surface 60A side. Therefore, the protruding portions 61 are portions with a lower fiber density and are bulkier than the recessed portions 62. The linear recesses 62 are arranged in a lattice pattern, and one protrusion 61 is arranged in one area defined by the lattice. The nonwoven fabric 60 may have a single layer structure as described above, but may also have a laminated structure of two or more layers. The nonwoven fabric 60 can be manufactured by the material and method described in, for example, JP 2010-168715 A. In this method, first, linear recesses 62 are formed in a fiber web by heat embossing. At this time, in the recesses 62, the heat-extensible fibers are compressed or fused and fixed in a state in which they are not thermally stretched. Next, hot air is blown by air-through processing to stretch the heat-extensible fibers present in the parts other than the recesses 62, thereby forming the protrusions 61.

[0039] The nonwoven fabric 70 shown in Fig. 7 has a plurality of first convex rows 71 extending along one direction (X direction) in plan view. In addition to the first convex row 71, the nonwoven fabric 70 also has a second convex row 72 positioned adjacent to the first convex row 71, and a third convex row 73 positioned adjacent to the first convex row 71. The first convex row 71, the second convex row 72, and the third convex row 73 extend along a common direction (X direction). The nonwoven fabric 70 has a longitudinal direction X that coincides with the extension direction of the first convex row 71, the second convex row 72, and the third convex row 73, and a transverse direction Y that is perpendicular to the longitudinal direction X. The first protruding portion row 71, the second protruding portion row 72, and the third protruding portion row 73 are all defined by recesses (fixed portions) 74 consisting of compressed portions formed by fusing or compressing the constituent fibers of the nonwoven fabric 70 and compressing them in the sheet thickness direction, and are portions that are thicker than the recesses 74. The heights of the protruding portions forming the first protruding portion row 71, the second protruding portion row 72, and the third protruding portion row 73 are all greater than the height of the recesses 74. The first convex portion row 71 is formed by arranging a plurality of first convex portions 71a in a row along the vertical direction X. The first convex portion row 71 includes a large convex portion 71ab and a small convex portion 71as as the first convex portions 71a. The small convex portion 71as has a smaller thickness and / or area than the large convex portion 71ab. In this embodiment, the small convex portion 71as has both a smaller thickness and area than the large convex portion 71ab. In the first protrusion row 71, a plurality of large protrusions 71ab and small protrusions 71as are alternately arranged in a row along the vertical direction X. In this first protrusion row 71, the first protrusions 71a (large protrusions 71ab, small protrusions 71as) adjacent to each other in the vertical direction X are connected to each other without being divided by recesses 74. Nonwoven fabric 70 can be produced by modifying the embossing pattern in the production method of nonwoven fabric 60.

[0040] In a nonwoven fabric having a concave-convex structure as shown in Figures 1 to 7, each component of the fiber treatment agent may be present independently over the entire area of ​​the nonwoven fabric, or may be present only in a part of the nonwoven fabric. When the fiber treatment agent is present only in a part of the nonwoven fabric, for example, the fiber treatment agent can be present only in the convex parts of the concave-convex structure, particularly only at the tops of the convex parts. In this way, the amount of fiber treatment agent used can be reduced while the antibacterial effect can be efficiently exerted.

[0041] The nonwoven fabric of the present invention is hydrophilic and has high antibacterial properties, and when used as, for example, a top sheet of an absorbent article, it is less likely to cause liquid backflow and has high dryness, so it is used as a constituent material of various hygienic articles. Hygienic articles using the nonwoven fabric of the present invention include, for example, absorbent articles such as disposable diapers, sanitary napkins, incontinence pads, and vaginal discharge liners, breast pads, wound covering sheets, and surgical gowns. In addition, since the hydrophilic property makes it easier to absorb sweat, examples of the hygienic articles include heating sheets and masks.

[0042] The absorbent article generally has an elongated shape having a vertical direction corresponding to the direction extending from the wearer's abdomen through the crotch to the back, and a horizontal direction perpendicular to the vertical direction. The absorbent article has a crotch portion disposed in the wearer's crotch, and a ventral side portion and a back side portion extending in front and behind the crotch portion. The crotch portion has an excretory part facing portion disposed facing the excretory part of the wearer when the absorbent article is worn, and the excretory part facing portion is usually located in the vertical center of the absorbent article or in the vicinity thereof.

[0043] An absorbent article generally comprises a top sheet located on the wearer's skin-facing side, a back sheet located on the non-skin-facing side, and an absorbent interposed between the two sheets. The top sheet may be a liquid-permeable sheet, such as a nonwoven fabric, a perforated nonwoven fabric with holes formed therein, or a perforated film. The top sheet may have an uneven surface on its skin-facing side. For example, a plurality of scattered convex portions may be formed on the skin-facing side of the top sheet. Alternatively, ridges and grooves extending in one direction may be alternately formed on the skin-facing side of the top sheet. For such a purpose, the top sheet may be formed using two or more nonwoven fabrics.

[0044] On the other hand, the back sheet may be, for example, a liquid-impermeable film or a spunbond-meltblown-spunbond laminated nonwoven fabric. A liquid-impermeable film may be provided with a plurality of micropores to impart water vapor permeability to the film. In order to further improve the feel of the absorbent article, a sheet with a good texture such as a nonwoven fabric may be laminated on the outer surface of the back sheet.

[0045] The absorbent body has an absorbent core. The absorbent core is composed of, for example, a stack of hydrophilic fibers such as cellulose including pulp, a mixed stack of the hydrophilic fibers and an absorbent polymer, a stack of absorbent polymer, a laminated structure in which an absorbent polymer is supported between two absorbent sheets, or the like. At least the skin-facing surface of the absorbent core may be covered with a liquid-permeable core wrap sheet, or the entire surface including the skin-facing surface and the non-skin-facing surface may be covered with the core wrap sheet. As the core wrap sheet, for example, a tissue paper made of hydrophilic fibers or a liquid-permeable nonwoven fabric can be used.

[0046] In addition to the above-mentioned top sheet, back sheet and absorbent body, leakage-preventing cuffs extending in the vertical direction may be arranged on both sides of the skin-facing side along the vertical direction, depending on the specific use of the absorbent article. The leakage-preventing cuffs generally have a base end and a free end. The leakage-preventing cuffs have a base end on the skin-facing side of the absorbent article and stand up from the skin-facing side. The leakage-preventing cuffs are made of a liquid-resistant or water-repellent material and are breathable. An elastic member made of rubber thread or the like may be arranged in a stretched state at or near the free end of the leakage-preventing cuff. When the absorbent article is worn, the elastic member contracts, causing the leakage-preventing cuffs to stand up toward the wearer's body, effectively preventing liquid excreted on the top sheet from leaking outward in the lateral direction of the absorbent article along the top sheet.

[0047] The absorbent article may further have an adhesive layer on the non-skin-facing surface. The adhesive layer is used to fix the absorbent article to an undergarment or another absorbent article when the absorbent article is worn.

[0048] When the nonwoven fabric of the present invention is applied to an absorbent article, the nonwoven fabric is preferably used in a portion of the absorbent article that requires liquid absorption. Examples of such portions include the top sheet of the absorbent article. Alternatively, when the exterior sheet forming the outer surface of the absorbent article has a two-layer structure consisting of an outer layer nonwoven fabric and an inner layer nonwoven fabric, the nonwoven fabric may be the inner layer nonwoven fabric located closer to the wearer's skin.

[0049] Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above-mentioned embodiments. For example, when the nonwoven fabric of the present invention has an uneven structure on its surface, the shape of the uneven structure is not limited to those shown in Figs. 1 to 7. The nonwoven fabric may contain additives other than the components (A) to (D) and zinc oxide, provided that the effects of the present invention are not impaired. EXAMPLES

[0050] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0051] [Examples 1 to 5] Polyoxyethylene lauryl ether phosphate potassium (trade name: Ampholex MP-2K, manufactured by Miyoshi Oil & Fats Co., Ltd., alkyl group carbon number 12, average molar number of added oxyalkylene groups n=2) was dissolved in ion-exchanged water to prepare an aqueous solution, and then 0.1 mol / L zinc sulfate solution (manufactured by Kanto Chemical Co., Ltd.) was added to the aqueous solution to obtain a dispersion of polyoxyethylene lauryl ether phosphate zinc, which is component (A). Then, the following components (B) to (D) were additionally added in predetermined amounts to the dispersion to prepare a dispersion for immersion. The amounts of components (B) to (D) added were such that the ratio of components (A) to (D) was the ratio shown in Table 1. Next, a nonwoven fabric was immersed and coated in the dispersion for immersion to obtain a nonwoven fabric having components (A) to (D) attached thereto. The amount of the fiber treatment agent containing components (A) to (D) attached was adjusted to within the range of 0.3±0.2% by mass relative to the mass of the air-through nonwoven fabric to which the fiber treatment agent was attached by adjusting the concentrations of components (A) to (D) in the dispersion. Specific amounts of the fiber treatment agent attached are as shown in Table 1. The air-through nonwoven fabric was made of 2.4 dtex PET / PE sheath-core composite fibers (short fibers with a fiber length of 51 mm) and had a basis weight of 18 g / m2. 2 It was. (B) Ingredient: Polyoxyethylene-modified polyhydric alcohol fatty acid ester (Kao Corporation, Emanon CH-60K) (C) Ingredient: Sodium dioctyl sulfosuccinate (manufactured by Kao Corporation, Pelex OT-P) (D) Ingredient: Stearyl dimethylaminoacetate betaine (manufactured by Kao Corporation, Amphitol 86B)

[0052] Example 6 A nonwoven fabric was obtained in the same manner as in Example 1 except that 1.0% by mass of zinc oxide was kneaded into the sheath of the PET / PE core-sheath type composite fiber constituting the nonwoven fabric, based on the mass of the air-through nonwoven fabric containing a fiber treatment agent and zinc oxide.

[0053] Comparative Example 1 A nonwoven fabric was obtained in the same manner as in Example 1, except that component (A) was not used.

[0054] Comparative Example 2 A nonwoven fabric was obtained in the same manner as in Example 1, except that components (B) to (D) were not used.

[0055] 〔evaluation〕 The nonwoven fabrics obtained in the Examples and Comparative Examples were evaluated for hydrophilicity, antibacterial activity, and wet-back amount by the following methods, taking into consideration their use as sanitary goods. The results are shown in Table 1.

[0056] [Hydrophilicity rate] A nonwoven fabric piece measuring 6 cm x 6 cm was cut out from the nonwoven fabric. Next, a nonwoven fabric piece in a state in which the pleats and wrinkles of the nonwoven fabric were stretched was prepared. Then, a cold spray was sprayed on a disposable diaper manufactured by Kao Corporation, Merries (registered trademark) First Premium Tape (S size), which was commercially available in June 2022, to solidify the adhesive and remove the top sheet, and the nonwoven fabric piece was attached in place of the removed top sheet. 0.1 g of ion-exchanged water was placed on the surface of the nonwoven fabric piece in 5 rows x 6 columns at intervals of 8 mm, and a total of 30 droplets were placed. Then, it was left to stand for 60 seconds. Then, the number of droplets that were absorbed by the ion-exchanged water and migrated to the diaper side or the nonwoven fabric was taken as the number of droplets absorbed in 60 seconds (W1). The measured value of W1 is the average value of n = 3. Then, the droplet absorption rate (W2) was calculated based on the following formula, and it was taken as the hydrophilicity rate. The number of droplets absorbed in 60 seconds (W1) was determined by visually checking whether or not droplets were present on the nonwoven fabric. Hydrophilicity rate = Droplet absorption rate (W2) = (Number of droplets absorbed in 60 seconds (W1) / 30 (Number of droplets initially placed)) × 100

[0057] [Antibacterial activity] The evaluation was carried out in accordance with JIS L 1902:2015, antibacterial test method for textile products. Table 1 shows the antibacterial activity value calculated by the bacterial liquid absorption method, which is defined as the antibacterial effect. If this antibacterial activity value is 2 or more, the target object is considered to have antibacterial properties.

[0058] [Amount of liquid returned] A cold spray was sprayed on Merry's (registered trademark) First Premium Tape (S size), a disposable diaper manufactured by Kao Corporation that was commercially available in June 2022, to solidify the adhesive and remove the top sheet. The nonwoven fabric obtained in the examples and comparative examples was reattached in place of the removed top sheet to prepare an absorbent article to be measured. The absorbent article to be measured was spread out flat and placed horizontally so that the skin-facing side (top sheet side) was facing up. Under this condition, 30 g of artificial urine was injected three times at a flow rate of 5 g / sec (a total of 90 g was injected). 10 minutes after the first injection, a second injection was performed for the same amount of artificial urine as the first injection. The injection point of the artificial urine was the horizontal center at a position 135 mm away from the end of the abdominal side side in the vertical direction (longitudinal direction) of the absorbent body. After the second artificial urine was poured into the absorbent article, it was left for 10 minutes, and then the collagen film was cut into 7 cm squares and four sheets were stacked on top of each other, which were placed on the artificial urine poured part of the absorbent article, and a pressure of 7 kPa was applied from above the collagen film for 1 minute. This allowed the artificial urine absorbed and held in the absorbent article to be absorbed into the collagen film. Then, the mass of the collagen film that had absorbed the artificial urine was measured. The mass of the collagen film before absorption was subtracted from this mass to calculate the mass of the artificial urine absorbed into the collagen film. This value was taken as the liquid return amount. Since the nonwoven fabric of Comparative Example 2 did not absorb the artificial urine, it is recorded in Table 1 as "not measurable."

[0059] [Table 1]

[0060] As is clear from the results shown in Table 1, the nonwoven fabrics of the examples containing the component (A) and one or more selected from the component (B), the component (C), and the component (D) have higher antibacterial activity and hydrophilicity than the nonwoven fabric of Comparative Example 1 which does not contain the component (A) and the nonwoven fabric of Comparative Example 2 which does not contain any of the components (B), (C), and (D). In addition, the amount of liquid return is smaller, and therefore the nonwoven fabrics have higher dryness. [Explanation of symbols]

[0061] 10, 20, 30, 40, 50, 60, 70 Nonwoven fabric 13, 23, 41, 61 Convex 14, 33, 34, 42, 62, 74 recess 31 1st protrusion 32 Second protrusion 51 Convex portion 52 Concave section 71 First convex row 71a First protrusion 72 Second convex row 73 3rd convex row

Claims

1. A nonwoven fabric for sanitary goods, comprising the following component (A) and one or more components selected from the group consisting of component (B), component (C) and component (D): Component (A): an alkyl phosphate salt or a polyoxyalkylene alkyl ether phosphate salt of an element of Group 11 or 12 of the periodic table Component (B): Nonionic surfactant Component (C): Anionic surfactant Component (D): Betaine-type surfactant

2. The nonwoven fabric for sanitary articles according to claim 1 , wherein the constituent fibers of the nonwoven fabric for sanitary articles are staple fibers.

3. 3. The nonwoven fabric for sanitary goods according to claim 1, wherein the constituent fibers of the nonwoven fabric for sanitary goods are core-sheath type composite fibers.

4. The nonwoven fabric for sanitary goods according to claim 3 , wherein the sheath of the core-sheath type composite fiber contains zinc oxide.

5. The nonwoven fabric for hygiene articles according to claim 1 , which is an air-through nonwoven fabric.

6. The nonwoven fabric for sanitary goods according to claim 1 , wherein the surface of the nonwoven fabric for sanitary goods has an uneven structure.

7. 7. The nonwoven fabric for sanitary goods according to claim 1, wherein the proportion of the component (A) to the total of the components (A), (B), (C), and (D) contained in the nonwoven fabric for sanitary goods is 65 mass% or less.

8. The nonwoven fabric for sanitary articles according to claim 1 , wherein the element is at least one selected from the group consisting of zinc, silver, and copper.

9. A sanitary article comprising the nonwoven fabric for sanitary articles according to any one of claims 1 to 8.

10. The hygiene article is an absorbent article, The sanitary article according to claim 9 , wherein an inner-layer nonwoven fabric in a top sheet or an exterior sheet in the absorbent article comprises the nonwoven fabric for sanitary articles.

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