Nonwoven fabric for sanitary item

Abstract

To provide a nonwoven fabric having anti-bacteria property and hydrophobicity and suitably used for sanitary items.SOLUTION: A nonwoven fabric 10 contains an alkyl phosphate ester salt or a polyoxyalkylene alkyl ether phosphate ester salt of group 11 or group 12 elements of the periodic table. The nonwoven fabric 10 is for sanitary articles. It is preferable that a chain length of the alkyl group in the alkyl phosphate ester salt or polyoxyalkylene alkyl ether phosphate salt is suitable to be 8 or more and 22 or less. It is also suitable that the constituent fibers of the nonwoven fabric 10 are short fibers. It is also preferable that the constituent fibers of the nonwoven fabric 10 are core sheath type composite fibers. It is also preferable that the nonwoven fabric 10 is an air-through nonwoven fabric. It is also preferable that the element is at least one selected from the group consisting of zinc, silver and copper.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] It is desirable for nonwoven fabrics used in sanitary articles such as disposable diapers and sanitary napkins to have antibacterial properties. From this perspective, Patent Document 1 proposes the use of nonwoven fabrics for diapers and napkins, the 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. The nonwoven fabric described in the document is also described as having antibacterial properties and hydrophilic properties.

[0003] Patent Document 2 proposes an absorbent article in which an antibacterial agent such as zinc oxide is kneaded into the fibers that make up the top sheet, and the surfaces of the fibers are covered with a fiber treatment agent made of an ethylene oxide-added nonionic surfactant, etc. The document states that this absorbent article is such that the fiber treatment agent falls off from the surfaces of the fibers upon contact with body fluids, exposing the antibacterial agent on the fiber surfaces and making the fibers hydrophobic. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-107144 A [Patent Document 2] Patent Publication No. 2021-52938 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, materials used in sanitary articles are required to have antibacterial properties, and may also be required to have hydrophobic properties depending on the part where the material is used. However, the nonwoven fabric described in Patent Document 1 above is hydrophilic and is unsuitable for applications requiring hydrophobicity. The top sheet in the absorbent article described in Patent Document 2 is hydrophobic after use, but is hydrophilic before use, so is also unsuitable for applications requiring hydrophobicity. The present invention therefore relates to a nonwoven fabric having antibacterial and hydrophobic properties and for use in hygiene articles. [Means for solving the problem]

[0006] The present invention provides a nonwoven fabric for sanitary articles which contains an alkyl phosphate salt or a polyoxyalkylene alkyl ether phosphate salt of an element of Group 11 or 12 of the periodic table. Effect of the Invention

[0007] According to the present invention, there is provided a nonwoven fabric which has antibacterial and hydrophobic properties and is suitable for use in sanitary articles. [Brief description of the drawings]

[0008] [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 that typically illustrates a nonwoven fabric according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to preferred embodiments thereof. The nonwoven fabric of the present invention contains an alkyl phosphate salt or a polyoxyalkylene alkyl ether phosphate salt. The alkyl phosphate salt used in the present invention has the general formula RPO3M 1 X The polyoxyalkylene alkyl ether phosphate salt is 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 used in the present invention 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 may be used alone or in combination of two or more. The inventors have found through their investigations that the inclusion of the alkyl phosphate salt or polyoxyalkylene alkyl ether phosphate salt in the nonwoven fabric allows the nonwoven fabric of the present invention to exhibit antibacterial properties and hydrophobic properties. A nonwoven fabric having such properties is suitable as a constituent material for sanitary articles. In particular, it is preferable to apply the nonwoven fabric of the present invention to parts of sanitary articles that require antibacterial properties and hydrophobic properties, such as leak-proof cuffs and exterior sheets in absorbent articles, from the viewpoint of making the most of the characteristics of the nonwoven fabric.

[0010] In order to make the above advantages more pronounced, 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.

[0011] The chain length of the alkyl group in the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more, from the viewpoint of imparting sufficient antibacterial properties and hydrophobicity to the nonwoven fabric. Moreover, the chain length of the alkyl group is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less, from the viewpoint of preventing the hydrophobicity of the nonwoven fabric from becoming excessively high. From the viewpoint of imparting sufficient antibacterial properties and hydrophobicity to the nonwoven fabric, 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, and 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.

[0012] 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 1represents 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 represented by the formula (I). In addition to the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt, 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).

[0013] RPO4M contained in the nonwoven fabric of the present invention 1 X (M 1 The definition of is the same as above. n -PO3M 1 X (M 1 The ratio of the polyoxyalkylene alkyl ether phosphate ester salt represented by the formula (1) is preferably within a predetermined range. When the nonwoven fabric contains the alkyl phosphate salt, the proportion of the alkyl phosphate salt is more preferably 1% by mass or more, even more preferably 2% by mass or more, and even more preferably 3% by mass or more, based on the mass of the nonwoven fabric to which the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is adhered, from the viewpoint of imparting sufficient antibacterial properties and hydrophobicity to the nonwoven fabric. Also, the proportion of the alkyl phosphate salt is preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the mass of the nonwoven fabric to which the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is adhered, from the viewpoint of preventing the hydrophobicity of the nonwoven fabric from becoming excessively high. When the nonwoven fabric contains the polyoxyalkylene alkyl ether phosphate salt, the proportion of the polyoxyalkylene alkyl ether phosphate salt 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 alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is attached, from the viewpoint of imparting sufficient antibacterial properties and hydrophobicity to the nonwoven fabric. Also, the proportion of the polyoxyalkylene alkyl ether phosphate salt 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 alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is attached, from the viewpoint of preventing the hydrophobicity of the nonwoven fabric from becoming excessively high. When the nonwoven fabric contains both the alkyl phosphate salt and the polyoxyalkylene alkyl ether phosphate salt, the total proportion of these is preferably 1.05% by mass or more, more preferably 2.1% by mass or more, and even more preferably 3.2% by mass or more, based on the mass of the nonwoven fabric to which the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is attached, from the viewpoint of imparting sufficient antibacterial properties and hydrophobicity to the nonwoven fabric. Also, the total proportion of the alkyl phosphate salt and the polyoxyalkylene alkyl ether phosphate salt is preferably 35% by mass or less, more preferably 23% by mass or less, and even more preferably 16% by mass or less, based on the mass of the nonwoven fabric to which the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is attached, from the viewpoint of preventing the hydrophobicity of the nonwoven fabric from becoming excessively high.

[0014] The proportion of the alkyl phosphate salt or the 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 the polyoxyalkylene alkyl ether phosphate salt, and 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.

[0015] The alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may be present 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. The alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may be present throughout the entire area of ​​the nonwoven fabric, or may be present partially. In order to cause the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt to be present on the surface of the fibers constituting the nonwoven fabric, for example, an aqueous dispersion containing the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may be applied to the nonwoven fabric as a raw material, and then the water may be removed. In order to cause the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt to be present in the fibers constituting the nonwoven fabric, for example, the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may be melt-kneaded with a resin constituting the fibers, and the kneaded mixture may be melt-spun. When the fibers constituting the nonwoven fabric are, for example, core-sheath type composite fibers, it is preferable from the viewpoint of effectively expressing antibacterial properties that the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is present in the sheath portion of the core-sheath type composite fibers.

[0016] The nonwoven fabric of the present invention may further contain an antibacterial agent in order to further enhance 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, and argan oil. Among these antibacterial agents, 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 improving antibacterial properties, ensuring spinnability of the fibers constituting the nonwoven fabric, reducing shedding from the fibers, and making the nonwoven fabric feel good to the touch when it touches 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 positions using a scanning electron microscope (SEM) or the like, approximating the shape of the cross section to a circle, and averaging the results using any image processing software such as WINROOF2018 (Mitani Shoji).

[0017] 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.

[0018] 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 alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt and the metal oxide, from the viewpoint of imparting sufficient antibacterial properties to the nonwoven fabric. The ratio of the metal 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 alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt and the metal oxide, from the viewpoint of ensuring the spinnability of the fibers constituting the nonwoven fabric, ensuring the strength of the nonwoven fabric, and preventing the texture from being damaged when the nonwoven fabric is made.

[0019] The nonwoven fabric of the present invention may further contain a water repellent agent in order to further enhance the hydrophobicity of the nonwoven fabric. Examples of the water repellent agent include silicone, liquid paraffin, and fluorine-containing polymers. These water repellents may be used alone or in combination of two or more.

[0020] The proportion of the water repellent 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 alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt and the water repellent (and metal oxide as required) from the viewpoint of imparting sufficient hydrophobicity to the nonwoven fabric. Also, the proportion of the water repellent 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 containing the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt and the water repellent (and metal oxide as required) from the viewpoint of maintaining a soft texture as a nonwoven fabric for sanitary goods.

[0021] By containing the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt (and a water repellent, if necessary) in the nonwoven fabric of the present invention, the hydrophobicity of the nonwoven fabric is increased. The degree of hydrophobicity can be expressed, for example, by the water repellency rate. The method for measuring the water repellency rate is as follows. <Water repellency measurement method> A nonwoven fabric piece measuring 6 cm x 6 cm is cut out from the nonwoven fabric. Next, with the pleats and wrinkles of the nonwoven fabric piece smoothed out, 0.1 g of ion-exchanged water is placed on the surface of the nonwoven fabric piece in 5 rows x 6 columns at intervals of 8 mm, to obtain a total of 30 droplets. Then, the nonwoven fabric piece is left to stand for 60 seconds. Thereafter, the number of droplets that have been absorbed and transferred to the back side of the nonwoven fabric piece or into the nonwoven fabric piece is measured, and this is taken as the number of absorbed droplets (W1). The measured value of W1 is the average value of n=3. Note that, after placing the droplets and leaving them to stand for 60 seconds, the nonwoven fabric piece is visually observed, and if there are no droplets on the nonwoven fabric piece, it is determined to be W1. Then, the droplet absorption rate (W2) is calculated based on the following formula, and the water repellency rate is calculated based on W2. Water repellency rate = 1 - droplet absorption rate (W2) = 1 - (number of absorbed droplets (W1) / 30 (number of droplets initially placed)) x 100

[0022] From the viewpoint of exhibiting sufficient hydrophobicity, the nonwoven fabric of the present invention preferably has a water repellency of 70% or more, more preferably 80% or more, and even more preferably 90% or more, as measured by the above method. The desired range of water repellency of the nonwoven fabric of the present invention varies depending on the application, and when the nonwoven fabric is used as a member that requires high leakproofness, such as a leakproof cuff or an exterior sheet, the higher the water repellency, the more desirable it is. On the other hand, when the nonwoven fabric is used as a surface material, etc., from the viewpoint of providing the nonwoven fabric with a certain level of liquid permeability, the water repellency measured by the above method is preferably 100% or less, more preferably 99% or less, and even more preferably 98% or less.

[0023] Since the nonwoven fabric of the present invention is hydrophobic as described above, it is preferable that the nonwoven fabric is substantially free of agents that increase the hydrophilicity of the nonwoven fabric (i.e., agents that decrease the hydrophobicity) as much as possible. However, the inclusion of such agents is permitted to the extent that the water repellency of the nonwoven fabric is not impaired. Examples of agents that increase the hydrophilicity of the nonwoven fabric include various surfactants.

[0024] 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 4.0 tex 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.

[0025] 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 feel and are 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.

[0026] 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.

[0027] 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 More preferably, it is 15 g / m or less. 2 More than 20g / m 2 It is even more preferred that:

[0028] The nonwoven fabric may have a portion where the fibers constituting the nonwoven fabric are turned into a film. The filming of the fibers of the nonwoven fabric occurs, for example, when the fibers are melted by the action of heat and the melt solidifies. Therefore, for example, when the nonwoven fabric is a spunbond nonwoven fabric, a plurality of embossed portions, i.e., portions where the fibers of the nonwoven fabric are turned into a film, are formed in the nonwoven fabric due to the thermal embossing process performed during the manufacturing process. On the other hand, air-through nonwoven fabrics and spunlace nonwoven fabrics do not require thermal embossing during the manufacturing process, but may be subjected to thermal embossing as an additional processing step after the manufacture of these nonwoven fabrics to form a plurality of embossed portions, i.e., portions where the fibers of the nonwoven fabric are turned into a film. It is desirable from the viewpoint of improving the water repellency of the nonwoven fabric that the portions where the fibers of the nonwoven fabric are turned into a film are present in the nonwoven fabric. From this viewpoint, the embossing ratio in the nonwoven fabric of the present invention, i.e., the ratio of the total area of ​​the embossed portions to the area of ​​the nonwoven fabric, is preferably 1% or more and 23% or less, more preferably 2% or more and 20% or less, and even more preferably 3% or more and 15% or less.

[0029] 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 6 show schematic diagrams of nonwoven fabrics having an uneven shape on at least one surface.

[0030] 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.

[0031] 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. 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 forms an uneven structure together with the convex portion 23 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] In a nonwoven fabric having a concave-convex structure as shown in Figures 1 to 6, the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may be present throughout the entire area of ​​the nonwoven fabric, or the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may be present only in a portion of the nonwoven fabric. When the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt is present only in a portion of the nonwoven fabric, the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt may 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 antibacterial effect can be efficiently expressed while suppressing the amount of the alkyl phosphate salt or the polyoxyalkylene alkyl ether phosphate salt used.

[0037] The nonwoven fabric of the present invention is used as a constituent material of various sanitary articles by taking advantage of its antibacterial and hydrophobic properties. Examples of sanitary articles including the nonwoven fabric of the present invention include absorbent articles such as disposable diapers, sanitary napkins, incontinence pads, and panty liners, breast pads, wound dressing sheets, and surgical gowns.

[0038] 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.

[0039] 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 or a perforated film. The top sheet may have an uneven surface on the 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 sheets of nonwoven fabric.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 leakproofness. Examples of such portions include leakproof cuffs arranged to extend in the longitudinal direction on both sides of the skin-facing side of the absorbent article, or an exterior sheet that forms the outer surface of the absorbent article.

[0045] 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 6. EXAMPLES

[0046] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, "%" means "% by mass".

[0047] Example 1 Potassium alkyl phosphate (product name: Gripper 4131, manufactured by Kao Corporation, alkyl group chain length 18) and zinc sulfate were dissolved in water to obtain a dispersion of zinc alkyl phosphate. The dispersion was applied to an air-through nonwoven fabric and dried to obtain a nonwoven fabric with a zinc alkyl phosphate attached thereto. The amount of the zinc alkyl phosphate attached was 6% by mass relative to the mass of the air-through nonwoven fabric with the zinc alkyl phosphate attached thereto. The air-through nonwoven fabric was made of 2.4 dtex PET / PE core-sheath type composite fiber (fiber length 51 mm) and had a basis weight of 18 g / m 2 It was.

[0048] Example 2 The amount of the zinc alkyl phosphate attached was as shown in Table 1. A nonwoven fabric was obtained in the same manner as in Example 1 except for this.

[0049] Example 3 In the step of obtaining a dispersion of zinc alkyl phosphate, another potassium alkyl phosphate (product name: Phosphanol ML-200, manufactured by Toho Chemical Industry Co., Ltd., alkyl chain length 12) was used instead of the potassium alkyl phosphate used in Example 1. The amount of zinc alkyl phosphate attached was as shown in Table 1. A nonwoven fabric was obtained in the same manner as in Example 1 except for this.

[0050] Example 4 A spunbond nonwoven fabric was used as the nonwoven fabric to which the zinc alkyl phosphate ester was attached. This spunbond nonwoven fabric was made of polypropylene fibers of 2.4 dtex and had a basis weight of 15 g / m 2 The amount of the zinc alkyl phosphate attached was as shown in Table 1. A nonwoven fabric was obtained in the same manner as in Example 1 except for this.

[0051] Example 5 In the step of obtaining a dispersion of zinc alkyl phosphate, the same potassium alkyl phosphate as used in Example 3 was used instead of the potassium alkyl phosphate used in Example 4. The amount of zinc alkyl phosphate attached was as shown in Table 1. A nonwoven fabric was obtained in the same manner as in Example 4 except for this.

[0052] Example 6 Polyoxyethylene lauryl ether phosphate potassium (product name: Amphorex MP-2K, manufactured by Miyoshi Oil & Fats, alkyl group chain length 12, average added mole number n of oxyalkylene groups) and zinc sulfate were dissolved in water to obtain a dispersion of polyoxyethylene lauryl ether phosphate zinc. The dispersion was applied to the same air-through nonwoven fabric as used in Example 1 and dried to obtain a nonwoven fabric having polyoxyethylene lauryl ether zinc phosphate attached thereto. The amount of polyoxyethylene lauryl ether zinc phosphate attached was 0.3 mass% based on the mass of the air-through nonwoven fabric having polyoxyethylene lauryl ether zinc phosphate attached thereto.

[0053] Comparative Example 1 A nonwoven fabric was obtained in the same manner as in Example 1, except that no zinc alkyl phosphate was used.

[0054] 〔evaluation〕 The nonwoven fabrics obtained in the Examples and Comparative Examples were evaluated for water repellency according to the above-mentioned method, taking into consideration their use as sanitary goods. In addition, the antibacterial activity was evaluated according to the following method. The results are shown in Table 1.

[0055] [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.

[0056] [Table 1]

[0057] As is clear from the results shown in Table 1, the nonwoven fabrics of Examples 1 to 5, which contain alkyl phosphate ester salts, have higher antibacterial activity and higher water repellency than the nonwoven fabric of the comparative example, which does not contain alkyl phosphate ester salts. It is also clear that the nonwoven fabric of Example 6 containing a polyoxyalkylene alkyl ether phosphate salt has higher antibacterial activity and higher water repellency than the nonwoven fabric of the Comparative Example not containing a polyoxyalkylene alkyl ether phosphate salt. [Explanation of symbols]

[0058] 10, 20, 30, 40, 50, 60 Nonwoven fabric with uneven structure

Claims

1. A nonwoven fabric for sanitary goods containing an alkyl phosphate ester salt or a polyoxyalkylene alkyl ether phosphate ester salt of an element of Group 11 or 12 of the periodic table.

2. 2. The nonwoven fabric for sanitary goods according to claim 1, wherein the alkyl group chain length in the alkyl phosphate ester salt or the polyoxyalkylene alkyl ether phosphate ester salt is 8 or more and 22 or less.

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

4. 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.

5. The nonwoven fabric for hygiene articles according to claim 1 or 2, wherein the nonwoven fabric for hygiene articles is an air-through nonwoven fabric.

6. 3. The nonwoven fabric for hygienic goods according to claim 1, which has a water repellency of 70% or more.

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

8. The nonwoven fabric for sanitary goods according to claim 1 or 2, further comprising zinc oxide.

9. The nonwoven fabric for sanitary goods according to claim 1 or 2, wherein the constituent fibers of the nonwoven fabric for sanitary goods have a film-like portion.

10. The nonwoven fabric for hygienic articles according to claim 1 or 2, further comprising a water repellent agent.

11. A sanitary article comprising the nonwoven fabric for sanitary articles according to claim 1 or 2.

12. the hygiene article is an absorbent article, The hygiene article according to claim 11, wherein the leak-proof cuffs or outer sheet of the absorbent article comprise the nonwoven fabric for hygiene articles.

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