absorbent articles

Abstract

To provide an absorbent article preventing leak from a non-skin-side sheet on a back side, while preventing stuffiness in a worn state.SOLUTION: An absorbent article 1 includes an absorbent core 21, a skin-side sheet located on a skin side with respect to the absorbent core 21, and a non-skin-side sheet located on the non-skin side with respect to the absorbent core 21 and made of one or a plurality of sheets. All the sheet materials constituting the non-skin-side sheet are made of fiber sheets. A part 5 containing a liquid fixative is provided between the absorbent core 21 and the non-skin-side sheet or between adjacent sheet materials in the non-skin-side sheet made of the plurality of sheet materials.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an absorbent article. [Background technology]

[0002] It has been proposed to use nonwoven fabrics as backsheets for absorbent articles such as disposable diapers and sanitary napkins. The use of a nonwoven fabric backsheet has the advantage of reducing stuffiness when the absorbent article is worn. For example, Patent Document 1 describes the use of a nonwoven fabric web containing triglycerides as the backsheet of an absorbent article. The document also describes that such a nonwoven fabric web reduces the breakthrough of liquids with low surface tension, such as loose stools from newborns. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2012-530855 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a backsheet made of nonwoven fabric as described in Patent Document 1 is used, there is a risk that excrement may leak out through the fibers of the nonwoven fabric depending on the wearer's movements, such as when the wearer performs strenuous activities. Therefore, an object of the present invention is to provide an absorbent article that prevents stuffiness when worn and improves leakage of excrement from the backsheet. [Means for solving the problem]

[0005] The present invention provides an absorbent core, a skin-side sheet located closer to the skin than the absorbent core, and a non-skin-side sheet consisting of one or more sheets located closer to the skin than the absorbent core, the sheet materials constituting the non-skin side sheet are all made of fiber sheets, The present invention provides an absorbent article having a region containing a liquid fixative between the absorbent core and the non-skin side sheet, or between adjacent sheet materials in the non-skin side sheet consisting of multiple sheet materials. [Effects of the Invention]

[0006] According to the present invention, an absorbent article is provided which can prevent moisture buildup when worn and can also prevent leakage from the non-skin-side sheet on the back surface. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a cross section along the lateral direction of one embodiment of the absorbent article of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a cross section along the lateral direction of another embodiment of the absorbent article of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on preferred embodiments with reference to the drawings, in which: Figure 1 shows a schematic cross section of one embodiment of an absorbent article of the present invention.

[0009] The absorbent article 1 shown in Fig. 1 has an absorbent core 21, a skin-side sheet 22 located closer to the skin than the absorbent core 21, and a non-skin-side sheet 23 located closer to the skin than the absorbent core 21. In this specification, the "skin-side" refers to the side facing the wearer's body when the absorbent article is worn. The "non-skin-side" refers to the side opposite the skin-side across the absorbent core when the absorbent article is worn.

[0010] The skin-side sheet 22 is a general term for all sheet materials located closer to the skin than the absorbent core 21. The skin-side sheet 22 may consist of a single sheet material or a laminate of multiple sheet materials. In either case, each sheet material is preferably composed of a fibrous sheet, and the skin-side sheet 22 as a whole is preferably liquid-permeable. As long as the skin-side sheet 22 as a whole is liquid-permeable, it is permissible for some of the sheet materials constituting the skin-side sheet 22 to contain sheet materials other than fibrous sheets, for example, perforated films.

[0011] The non-skin-side sheet 23 is a general term for all sheet materials located on the non-skin side of the absorbent core 21. Like the skin-side sheet 22, the non-skin-side sheet 23 may consist of a single sheet material or a laminate of multiple sheet materials. In either case, each sheet material is preferably composed of a fiber sheet, and the non-skin-side sheet 23 as a whole is preferably breathable. In particular, it is preferable that the sheet materials constituting the non-skin-side sheet 23 do not include a liquid-impermeable film, from the viewpoint of effectively suppressing stuffiness when the absorbent article 1 is worn.

[0012] 1, in this embodiment, the sheet material constituting the skin-side sheet 22 is two sheets: a portion of the core wrap sheet material 24 that covers the entire absorbent core 21, located on the skin side of the absorbent core 21 (hereinafter, this portion will be referred to as the "skin-side first sheet material 22a"), and a skin-side second sheet material 22b that is located closer to the skin than the skin-side first sheet material 22a and that comes into contact with the wearer's body when the absorbent article 1 is worn. In other words, the skin-side sheet 22 has a laminated structure of the skin-side first sheet material 22a and the skin-side second sheet material 22b. The two sheet materials 22a, 22b are simply overlapped with each other or are partially joined together.

[0013] 1, in this embodiment, the sheet material constituting the non-skin side sheet 23 is two sheets: a portion of the core wrap sheet material 24 that covers the entire absorbent core 21, located on the non-skin side of the absorbent core 21 (hereinafter, this portion will be referred to as the "non-skin side first sheet material 23a"), and a non-skin side second sheet material 23b that is located further on the non-skin side than the non-skin side first sheet material 23a and faces outward when the absorbent article 1 is worn. In other words, the non-skin side sheet 23 has a laminated structure of the non-skin side first sheet material 23a and the non-skin side second sheet material 23b. The two sheet materials 23a, 23b are simply overlapped or partially joined together.

[0014] The absorbent core 21 in the absorbent article 1 of this embodiment has the function of absorbing and retaining bodily waste excreted by the wearer. For this purpose, the absorbent core 21 can be made of a mixed stack of a hydrophilic fiber material such as wood pulp and absorbent polymer particles. When the absorbent core 21 is made of this mixed stack, it is preferable to cover the periphery of the absorbent core 21 with a core wrap sheet material 24, as shown in Figure 1, from the viewpoint of preventing the absorbent polymer particles from falling off. Alternatively, the absorbent core 21 may be a water-absorbent structure in which absorbent polymer particles are sandwiched and fixed between two liquid-permeable sheets.

[0015] In addition to the above-described configuration, the absorbent article 1 of this embodiment has a portion 5 containing a liquid immobilizing agent for retaining and immobilizing excrement excreted by the wearer (hereinafter also referred to as a "liquid immobilizing portion"). The liquid immobilizing agent has, for example, the function of (i) absorbing excrement and reducing the fluidity of the excrement, or (ii) increasing the viscosity of the excrement and reducing its fluidity.

[0016] The liquid fixation agent is generally in the form of a powder, and is preferably deposited at a predetermined location in the thickness direction of the absorbent article 1 to form a layer of liquid fixation region. In the embodiment shown in Fig. 1, a layer of liquid fixation region 5 is shown disposed between a first non-skin-side sheet material 23a and a second non-skin-side sheet material 23b in the non-skin-side sheet 23. In other words, the liquid fixation region 5 is located between adjacent sheet materials 23a and 23b in the non-skin-side sheet 23.

[0017] In the absorbent article 1 of this embodiment, the advantage of arranging the liquid immobilizing portion 5 on the non-skin side of the absorbent core 21 is as follows. In this embodiment, the breathability of the non-skin-side sheet 23 prevents stuffiness when the absorbent article 1 is worn. The breathability of the non-skin-side sheet 23 is a trade-off between its ability to block liquid permeation and its ability to block liquid permeation. Therefore, using a breathable non-skin-side sheet 23 raises concerns about leakage of excrement through the non-skin-side sheet 23. Therefore, in this embodiment, the liquid immobilization region 5 is positioned closer to the skin than the absorbent core 21. Therefore, in the event that excrement that cannot be retained by the absorbent core 21 migrates toward the non-skin-side sheet 23, or in the event that excrement retained in the absorbent core 21 migrates toward the non-skin-side sheet 23 due to the wearer's body pressure or changes in body pressure during movement, the exuded excrement is immobilized in the liquid immobilization region 5, thereby preventing further exudation. As a result, even if the non-skin-side sheet 23 is breathable, leakage of excrement to the outside through the non-skin-side sheet 23 is effectively suppressed.

[0018] To further enhance the above advantages, the liquid fixation region 5 is preferably disposed at least in the central region in the longitudinal direction of the absorbent article 1, and more preferably extends longitudinally from the front region through the central region to the rear region. From the same viewpoint, the liquid fixation region 5 is preferably disposed at least over the entire transverse area of ​​the central region. The central region has the longitudinal direction and the lateral direction, is located in the longitudinal center of the absorbent article 1 which is long in one direction, and is a region that faces the excretory area of ​​the wearer when the absorbent article 1 is worn. The front region is a region that is located more ventral than the excretory area of ​​the wearer when the absorbent article 1 is worn, and the rear region is a region that is located more dorsal than the excretory area of ​​the wearer when the absorbent article 1 is worn.

[0019] The liquid immobilizing agent constituting the liquid immobilizing portion 5 is an agent that has the function of absorbing excrement and reducing the fluidity of the excrement, and examples thereof include absorbent polymers. Examples of absorbent polymers include various hydrogel materials made of crosslinked hydrophilic polymers that are insoluble in water. Examples of hydrophilic polymers include sodium polyacrylate, acrylic acid-vinyl alcohol copolymers, (starch-acrylic acid) graft polymers, isobutylene-maleic anhydride copolymers and their saponification products, potassium polyacrylate, and cesium polyacrylate. These may be used alone or in combination of two or more. Absorbent polymer particles vary in shape, including amorphous, block, bale-shaped, spherical aggregate, and spherical types, and any of these may be used.

[0020] On the other hand, among liquid fixatives, various thickeners can be mentioned as agents that have the function of increasing the viscosity of excrement and reducing its fluidity. Examples of the thickener that can be used include cellulose derivative thickeners and polysaccharide thickeners. These thickeners can be used alone or in combination of two or more. Examples of cellulose derivative thickeners include carboxymethyl cellulose, ethyl cellulose acetate, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, etc. When carboxymethyl cellulose is used, it is preferable that the degree of etherification is, for example, from 0.5 to 1.5, in order to further enhance the liquid immobilization ability. Examples of polysaccharide thickeners include xanthan gum, alginic acid, carrageenan, agar, pectin, gum arabic, tremel gum, tamarind seed gum, guar gum, tara gum, locust bean gum, gellan gum, karaya gum, and succinoglycan. Among these, from the viewpoints of high liquid immobilization ability and easy handling, it is preferable to use at least one selected from carboxymethylcellulose, xanthan gum, and alginic acid, and it is even more preferable to use alginic acid. Among liquid immobilizing agents, alginic acid has a high ability to thicken excrement, so its use further reduces the fluidity of excrement. As a result, the amount of excrement passing through the liquid immobilization region 5 is reduced, preventing lateral diffusion of excrement in the non-skin-side sheet 23. A small lateral diffusion area of ​​excrement (hereinafter also referred to as the "liquid diffusion area") means that the thickener used as the liquid immobilizing agent has a high thickening ability and is able to suppress liquid migration from the liquid immobilization region 5 to the non-skin-side sheet 23. In other words, the liquid diffusion area can be used as a measure of prevention of leakage from the non-skin-side sheet 23 in an absorbent article.

[0021] From the viewpoint of reliably immobilizing the excrement and effectively preventing leakage of the excrement through the non-skin side sheet 23, the basis weight of the liquid immobilizing agent in the liquid immobilizing region 5 is preferably 30 g / m 2 More preferably, 100 g / m 2 More preferably, 150 g / m 2 More preferably, the thickness is 350 g / m 2 Less than 300 g / m 2 More preferably 250 g / m or less 2 The following is the result.

[0022] The liquid fixing region 5 can be formed by directly sprinkling a powder of the liquid fixing agent onto the non-skin-side first sheet material 23a and / or the non-skin-side second sheet material 23b, by holding the liquid fixing agent on a substrate such as nonwoven fabric or paper, or by applying or dripping a liquid in which the liquid fixing agent is dissolved or dispersed in a solvent such as water. Depending on how the liquid fixing region 5 is formed, part of the liquid fixing agent may be embedded in the non-skin-side first sheet material 23a and / or the non-skin-side second sheet material 23b.

[0023] Next, another embodiment of the present invention will be described with reference to Fig. 2. For points not specifically explained regarding the embodiment shown in Fig. 2, the explanation of the embodiment shown in Fig. 1 above applies as appropriate. In Fig. 2, the same components as those in Fig. 1 are designated by the same reference numerals.

[0024] The absorbent article 1 of the embodiment shown in Fig. 2 differs from the previously described embodiment shown in Fig. 1 in the position of the liquid fixation region 5. In the embodiment shown in Fig. 1, the liquid fixation region 5 is located between adjacent sheet materials 23a and 23b in the non-skin side sheet 23, whereas in this embodiment, the liquid fixation region 5 is located between the absorbent core 21 and the non-skin side sheet 23. More specifically, the liquid fixation region 5 is located so as to abut the non-skin side surface of the absorbent core 21 and the first non-skin side sheet material 23a. As a result, the liquid fixation region 5, together with the absorbent core 21, is covered by the core wrap sheet material 24. According to this embodiment, the absorbent core 21 and the liquid fixation portion 5 are in direct contact with each other. Therefore, when excrement that cannot be held by the absorbent core 21 migrates to the non-skin side sheet 23, or when excrement held in the absorbent core 21 seeps out of the absorbent core 21 and migrates to the non-skin side sheet 23 due to the wearer's body pressure or changes in body pressure during movement, the seeped excrement can be immediately fixed in the liquid fixation portion 5, and leakage of excrement to the outside through the non-skin side sheet 23 is more effectively suppressed than in the embodiment shown in FIG. 1.

[0025] In addition, Figure 2 shows a state in which the liquid fixation region 5 is arranged between the absorbent core 21 and the core wrap sheet material 24, but instead, a portion of the liquid fixation region 5 may be embedded in the absorbent core 21 and / or the core wrap sheet material 24.

[0026] Next, common features of the above embodiments will be described. The skin-side second sheet material 22b, which is one of the sheet materials constituting the skin-side sheet 22, can be a liquid-permeable sheet, such as a nonwoven fabric. The skin-facing surface of the skin-side second sheet material 22b may have an uneven shape. For example, a plurality of scattered convex portions can be formed on the skin-facing surface of the skin-side second sheet material 22b. Alternatively, ridges and grooves extending in one direction can be formed alternately on the skin-facing surface of the skin-side second sheet material 22b. For such purposes, the skin-side second sheet material 22b can be formed using two or more sheets of nonwoven fabric.

[0027] Liquid-permeable sheets, such as nonwoven fabrics or tissue paper, can be used for the core wrap sheet material 24, i.e., the skin-side first sheet material 22a and the non-skin-side first sheet material 23a. As long as the core wrap sheet material 24 is liquid-permeable, it is preferable that the mesh be fine enough to prevent the absorbent polymer particles contained in the absorbent core 21 from falling out.

[0028] Of the sheet materials constituting the non-skin side sheet 23, the outermost non-skin side second sheet material 23b is preferably a fiber sheet that is breathable and highly resistant to liquid penetration. Examples of such fiber sheets include nonwoven fabrics containing meltblown nonwoven fabrics. Specifically, the non-skin side second sheet material 23b can be a meltblown nonwoven fabric itself. Alternatively, the non-skin side second sheet material 23b can be a laminated nonwoven fabric in which a spunbond nonwoven fabric is disposed on at least one side of a meltblown nonwoven fabric, such as a spunbond-meltblown (SM) composite nonwoven fabric or a spunbond-meltblown-spunbond (SMS) composite nonwoven fabric. The spunbond layer or meltblown layer in the above-mentioned laminated nonwoven fabric may be composed of multiple layers. For example, the spunbond-meltblown (SM) composite nonwoven fabric may be spunbond-meltblown (SM), spunbond-meltblown-meltblown (SMM), spunbond-spunbond-meltblown (SSM), spunbond-spunbond-meltblown-meltblown (SSMM), spunbond-spunbond-meltblown-meltblown-meltblown (SSMMM), spunbond-spunbond-meltblown-meltblown-meltblown (SSMMM), spunbond-spunbond-meltblown-meltblown-meltblown Examples of spunbond-meltblown-spunbond (SMS) composite nonwoven fabrics include spunbond-meltblown-meltblown-spunbond (SMMS), spunbond-spunbond-meltblown-meltblown-spunbond (SSMMS), spunbond-spunbond-meltblown-meltblown-meltblown-spunbond (SSMMMS), spunbond-spunbond-meltblown-meltblown-meltblown-spunbond (SSMMMS), spunbond-spunbond-meltblown-meltblown-meltblown-spunbond (SSMMMMS), etc. In particular, from the viewpoint of achieving strength sufficient to withstand wear, it is preferable to use a spunbond-meltblown-spunbond (SMS) composite nonwoven fabric.

[0029] The nonwoven fabrics described above that include at least a meltblown nonwoven fabric preferably have a water pressure resistance of 100 mmAq or more, more preferably 200 mmAq or more, and even more preferably 300 mmAq or more, in order to have high resistance to liquid permeation. Furthermore, from the viewpoint of ensuring breathability that can prevent stuffiness, the water pressure resistance is preferably 20,000 mmAq or less, more preferably 10,000 mmAq or less, and even more preferably 5,000 mmAq or less. The water pressure resistance is measured in accordance with JIS L1092.

[0030] In order for the nonwoven fabric having at least a meltblown nonwoven fabric to exhibit such water pressure resistance, the basis weight of the meltblown nonwoven fabric in the nonwoven fabric is 1 g / m 2 It is preferable that the content is 2 g / m or more. 2 More preferably, it is 3 g / m or more. 2 From the same viewpoint, the basis weight of the meltblown nonwoven fabric is more preferably 30 g / m or more. 2 Preferably, it is 20 g / m or less. 2 More preferably, it is 15 g / m or less. 2 It is even more preferred that: To sum up, the basis weight of meltblown nonwoven fabric is 1g / m 2 More than 30g / m 2 Preferably, it is 2 g / m or less. 2 More than 20g / m 2 More preferably, it is 3 g / m or less. 2 More than 15g / m 2 It is even more preferred that:

[0031] Meltblown nonwoven fabrics exhibit high liquid blocking properties due to the small fiber diameter of their constituent fibers, which is a result of their manufacturing method. The fiber diameter of the constituent fibers of meltblown nonwoven fabrics is preferably 0.1 μm to 10 μm, more preferably 0.3 μm to 7 μm, and even more preferably 0.5 μm to 5 μm.

[0032] When an SMS composite nonwoven fabric is used as the non-skin side second sheet material 23b, the constituent fibers of the composite nonwoven fabric preferably contain a thermoplastic resin having fiber-forming ability and a triglyceride. While various thermoplastic resins having fiber-forming ability are known in the art, in the present invention, it is preferable to use a polyolefin resin as the thermoplastic resin, from the viewpoint of obtaining a nonwoven fabric with high liquid barrier properties.

[0033] The polyolefin resin may be a homopolymer or copolymer of a lower olefin such as ethylene or propylene, etc. Specific examples include polyethylene, polypropylene, and ethylene-α-olefin copolymer. Examples of polyethylene include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Examples of polypropylene include isotactic polypropylene and syndiotactic polypropylene. Low stereoregular homopolypropylene can also be used as the polypropylene. Low stereoregular homopolypropylene has the following properties: 13 It is a homopolypropylene with a mesopentad fraction (mmmm [%]) of 90% or less as measured by C-NMR. Examples of ethylene-α-olefin copolymers include copolymers of ethylene with α-olefins such as propylene, 1-butene, 1-pentene, and 1-hexene. Examples of copolymers include random copolymers, block copolymers, and graft copolymers. It is particularly preferable to use a random copolymer of ethylene and propylene (hereinafter also referred to as a "random propylene copolymer"). Of these polyolefin resins, polypropylene and polyolefins containing propylene as a copolymerization component are preferably used from the viewpoint of high fiber-forming ability and high liquid barrier properties of the resulting nonwoven fabric. The polyolefin resin is also preferably a blend of homopolypropylene and a random propylene copolymer or a low stereoregular homopolypropylene.

[0034] When the non-skin side second sheet material 23b is made of an SMS composite nonwoven fabric, the fibers constituting the composite nonwoven fabric may contain only one type of the above-mentioned polyolefin resin, or may contain two or more types. The fibers constituting the SMS composite nonwoven fabric may contain only the above-mentioned polyolefin resin as the constituent resin, or may contain other thermoplastic resins in addition to the polyolefin resin. In the latter case, it is preferable that the constituent resin of the fibers contains 50 mass % or more of the above-mentioned polyolefin resin.

[0035] When the non-skin side second sheet material 23b is made of an SMS composite nonwoven fabric, triglyceride, another component contained in the fibers constituting the composite nonwoven fabric, is used to reduce the surface tension of the fibers constituting the composite nonwoven fabric and thereby enhance the barrier properties of the nonwoven fabric against liquids. The triglyceride may be present in a state of adhering to the surface of the fibers or may be kneaded into the resin constituting the fibers. In particular, it is preferable that triglycerides are contained in the meltblown layer of the SMS composite nonwoven fabric, since this further enhances the barrier properties of the nonwoven fabric against liquids.

[0036] The triglyceride may be a triglyceride derived from saturated fatty acids, a triglyceride derived from unsaturated fatty acids, or a triglyceride derived from saturated and unsaturated fatty acids. In any case, the number of carbon atoms in the fatty acid may be, for example, 12 or more and 24 or less. From the viewpoint of further improving the barrier properties of the nonwoven fabric against liquids, the number of carbon atoms in the fatty acid is preferably 14 or more and 22 or less, and more preferably 16 or more and 20 or less. The triglyceride may be used alone or as a mixture of two or more types of triglycerides. The fibers constituting the SMS composite nonwoven fabric may contain only triglycerides as glycerides, or may contain monoglycerides and / or diglycerides in addition to triglycerides as long as the desired effects of the present invention are achieved. However, from the viewpoint of improving the liquid barrier properties of the SMS composite nonwoven fabric, it is preferable to use only triglycerides as glycerides.

[0037] The triglyceride used in the present invention is preferably one in which the number of carbon atoms in the fatty acid residue is adjusted. The use of such a triglyceride can improve the barrier properties of the SMS composite nonwoven fabric against liquids. Specifically, the following (a) or (b) is preferably used as the triglyceride: (a) A triglyceride comprising a mixture of a triglyceride containing at least one group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least one group derived from a fatty acid having 18 carbon atoms in one molecule. (b) A triglyceride containing at least one group derived from a fatty acid having 16 carbon atoms and one group derived from a fatty acid having 18 carbon atoms in one molecule.

[0038] In the case of (a), two or more types of triglycerides are used. At least one of the types of triglycerides contains at least one group derived from a fatty acid having 16 carbon atoms (i.e., a saturated fatty acid or an unsaturated fatty acid) in the molecule (this triglyceride is also referred to as "triglyceride 16"). Triglyceride 16 preferably contains at least one group derived from a fatty acid having 16 carbon atoms in the molecule. Triglyceride 16 may contain one group derived from a fatty acid having 16 carbon atoms in the molecule (this triglyceride is also referred to as "triglyceride P"), two groups derived from a fatty acid having 16 carbon atoms in the molecule (this triglyceride is also referred to as "triglyceride PP"), or three groups derived from a fatty acid having 16 carbon atoms in the molecule (this triglyceride is also referred to as "triglyceride PPP"). The type of the remaining fatty acid residue in triglyceride P and triglyceride PP is not particularly limited, and may be, for example, a residue of a saturated fatty acid or an unsaturated fatty acid having 12 to 24 carbon atoms.

[0039] Triglyceride 16 may consist solely of triglyceride P, may consist solely of triglyceride PP, or may consist solely of triglyceride PPP. Triglyceride 16 may be a combination of two or more selected from triglyceride P, triglyceride PP, and triglyceride PPP. For example, triglyceride 16 may be a combination of triglyceride P and triglyceride PP, a combination of triglyceride P and triglyceride PPP, a combination of triglyceride PP and triglyceride PPP, or a combination of triglyceride P, triglyceride PP, and triglyceride PPP.

[0040] In case (a), at least one of the multiple triglycerides contains at least one group derived from a fatty acid having 18 carbon atoms (i.e., a saturated fatty acid or an unsaturated fatty acid) in one molecule (this triglyceride is also referred to as "triglyceride 18"). Triglyceride 18 preferably contains at least one group derived from a fatty acid having 18 carbon atoms in one molecule. Triglyceride 18 may contain one group derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride S"), two groups derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride SS"), or three groups derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride SSS"). The type of the remaining fatty acid residue in triglyceride S and triglyceride SS is not particularly limited, and may be, for example, a residue of a saturated fatty acid or an unsaturated fatty acid having 12 to 24 carbon atoms.

[0041] Triglyceride 18 may consist solely of S triglycerides, may consist solely of SS triglycerides, or may consist solely of SSS triglycerides. Triglyceride 18 may be a combination of two or more selected from triglyceride S, triglyceride SS, and triglyceride SSS. For example, triglyceride 18 may be a combination of triglyceride S and triglyceride SS, a combination of triglyceride S and triglyceride SSS, a combination of triglyceride SS and triglyceride SSS, or a combination of triglyceride S, triglyceride SS, and triglyceride SSS.

[0042] In the case of (a), the triglycerides may consist solely of triglyceride 16 and triglyceride 18, or may contain other triglycerides in addition to triglyceride 16 and triglyceride 18. The other triglycerides include triglycerides that have neither a group derived from a fatty acid having 16 carbon atoms nor a group derived from a fatty acid having 18 carbon atoms.

[0043] If the group derived from a fatty acid having 16 carbon atoms is "P," the group derived from a fatty acid having 18 carbon atoms is "S," and the groups derived from other fatty acids are "X" and "Y," the combination of groups derived from fatty acids that constitute a triglyceride is either PPP (i.e., triglyceride PPP), SSS (i.e., triglyceride SSS), PPX (i.e., triglyceride PP), SSX (i.e., triglyceride SS), PXY (i.e., triglyceride P), or SXY (i.e., triglyceride S). The structures of triglycerides represented by PPP, SSS, PPX, SSX, PXY, and SXY are (A) to (L) below.

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] From the viewpoint of obtaining a nonwoven fabric with even higher barrier properties against liquids, it is preferable to use a triglyceride composed only of triglycerides 16 and 18.

[0050] In the case of (b), at least one type of triglyceride can be used. This triglyceride contains, in one molecule, at least one group derived from a fatty acid having 16 carbon atoms (i.e., saturated fatty acid or unsaturated fatty acid) and at least one group derived from a fatty acid having 18 carbon atoms (i.e., saturated fatty acid or unsaturated fatty acid). In particular, a triglyceride containing, in one molecule, at least one group derived from a saturated fatty acid having 16 carbon atoms and at least one group derived from a saturated fatty acid having 18 carbon atoms is preferred, as it allows for a nonwoven fabric with even higher liquid barrier properties to be obtained.

[0051] In the case of (b), if a group derived from a fatty acid with 16 carbon atoms is "P," a group derived from a fatty acid with 18 carbon atoms is "S," and a group derived from any other fatty acid is "X," the combination of aliphatic groups that make up the triglyceride is either SSP, SPP, or SPX. The structure of a triglyceride represented by SPX is either (M) or (O) below. The same applies to SSP and SPP.

[0052] [ka]

[0053] In the case of (b), the triglyceride may be composed solely of triglycerides containing at least one group derived from a fatty acid having 16 carbon atoms and at least one group derived from a fatty acid having 18 carbon atoms in one molecule. Alternatively, the triglyceride may be composed solely of triglycerides containing at least one group derived from a fatty acid having 16 carbon atoms and at least one group derived from a fatty acid having 18 carbon atoms, and other glycerides. Examples of other triglycerides include triglycerides that contain neither a group derived from a fatty acid having 16 carbon atoms nor a group derived from a fatty acid having 18 carbon atoms in one molecule. From the viewpoint of obtaining a nonwoven fabric with even higher liquid barrier properties, it is preferable to use only triglycerides that contain at least one group derived from a fatty acid having 16 carbon atoms and at least one group derived from a fatty acid having 18 carbon atoms in one molecule.

[0054] In the present invention, a combination of (a) and (b) can also be used. Specifically, a combination of triglyceride PPP, triglyceride SSS, and SPX can be used. Alternatively, a combination of triglyceride PPP, triglyceride SSS, and SSP, or a combination of triglyceride PPP, triglyceride SSS, and SPP can also be used. Furthermore, a combination of triglyceride PPX, triglyceride SSX, and triglyceride SPX, a combination of triglyceride PPX, triglyceride SSX, and triglyceride SSP, a combination of triglyceride PPX, triglyceride SSX, and triglyceride SPP, a combination of triglyceride PXY, triglyceride SXY, and triglyceride SPX, a combination of triglyceride PXY, triglyceride SXY, and triglyceride SSP, or a combination of triglyceride PXY, triglyceride SXY, and triglyceride SPP can also be used.

[0055] In either case (a) or (b) above, the triglyceride used in the present invention preferably does not contain groups derived from unsaturated fatty acids, from the viewpoint of improving the liquid barrier properties of the SMS composite nonwoven fabric. "Doing not contain groups derived from unsaturated fatty acids" encompasses both cases where no groups derived from unsaturated fatty acids are contained at all, and cases where a small amount of unsaturated fatty acids is inevitably contained. "In cases where a small amount of unsaturated fatty acids is inevitably contained" refers to, for example, cases where the proportion of groups derived from unsaturated fatty acids is 2% by mass or less, based on the total amount of groups derived from fatty acids contained in all triglycerides contained in the fiber.

[0056] In the present invention, it is preferable to adjust the proportion of groups derived from fatty acids having 16 carbon atoms and the proportion of groups derived from fatty acids having 18 carbon atoms for all triglycerides contained in the constituent fibers of the SMS composite nonwoven fabric, from the viewpoint of further improving the liquid barrier properties of the SMS composite nonwoven fabric.

[0057] The proportion of groups derived from fatty acids having 16 carbon atoms is preferably 1 mass % or more, based on the total amount of groups derived from fatty acids, for all triglycerides contained in the constituent fibers of the SMS composite nonwoven fabric, from the viewpoint of further improving the liquid barrier properties of the SMS composite nonwoven fabric. From the viewpoint of even further improving the barrier properties, the proportion is more preferably 10 mass % or more, even more preferably 15 mass % or more, even more preferably 20 mass % or more, and particularly preferably 25 mass % or more. Furthermore, the proportion is preferably less than 60% by mass from the viewpoint of further improving the liquid barrier property of the SMS composite nonwoven fabric, and from the viewpoint of still further improving the barrier property, it is more preferably 55% by mass or less, and even more preferably 50% by mass or less. The proportion is preferably 1% by mass or more and less than 60% by mass, more preferably 10% by mass or more and less than 60% by mass, even more preferably 15% by mass or more and less than 60% by mass, even more preferably 20% by mass or more and 55% by mass or less, and particularly preferably 25% by mass or more and 50% by mass or less.

[0058] The proportion of groups derived from fatty acids having 18 carbon atoms is preferably 5% by mass or more, based on the total amount of groups derived from fatty acids, for all triglycerides contained in the constituent fibers of the SMS composite nonwoven fabric, from the viewpoint of further improving the liquid barrier properties of the SMS composite nonwoven fabric, and from the viewpoint of even further improving the barrier properties, is more preferably 35% by mass or more, even more preferably 40% by mass or more, still more preferably 45% by mass or more, and particularly preferably 50% by mass or more. Furthermore, from the viewpoint of further improving the liquid barrier properties of the SMS composite nonwoven fabric, the proportion is preferably less than 90% by mass, and from the viewpoint of further improving the barrier properties, the proportion is more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less. The proportion is preferably 5% by mass or more and less than 90% by mass, more preferably 35% by mass or more and less than 90% by mass, even more preferably 40% by mass or more and less than 90% by mass, even more preferably 45% by mass or more and less than 70% by mass, and even more preferably 50% by mass or more and less than 65% by mass.

[0059] With regard to the ratio of groups derived from fatty acids having 16 carbon atoms to groups derived from fatty acids having 18 carbon atoms, the mass ratio (C18 / C16) of groups derived from fatty acids having 18 carbon atoms to groups derived from fatty acids having 16 carbon atoms contained in all triglycerides contained in the fibers is preferably 1.0 to 15.0 in order to further enhance the barrier properties of the SMS composite nonwoven fabric against liquids. To further enhance this advantage, the mass ratio (C18 / C16) of groups derived from fatty acids having 18 carbon atoms to groups derived from fatty acids having 16 carbon atoms is more preferably 1.1 to 10.0, even more preferably 1.2 to 5.0, and even more preferably 1.2 to 2.7.

[0060] The proportions of groups derived from fatty acids having 16 carbon atoms and groups derived from fatty acids having 18 carbon atoms, based on the total amount of groups derived from fatty acids contained in all triglycerides contained in the fiber, are measured by the following method. The triglycerides present on the surface of the fibers constituting the SMS composite nonwoven fabric are extracted using a good solvent for triglycerides, such as toluene. The ester bonds in the extracted triglycerides are hydrolyzed with alkali, and the methyl-esterified fatty acids are quantitatively analyzed by gas chromatography.

[0061] The presence of alkyl chains with different carbon numbers within a single triglyceride molecule can be determined using TOF-MS (time-of-flight mass spectrometry). Specifically, the molecular weight distribution of triglycerides is measured using TOF-MS, and the presence of alkyl groups with different carbon numbers within the molecule can be determined from the molecular weight of the single molecule. The presence of alkyl chains with different carbon numbers within a single molecule of a compound with the same molecular weight can be determined using a tandem mass spectrometer (MS / MS). Specific ions are selected in the first mass separation section, and the fragment ions generated by colliding with an inert gas are separated and detected in the second mass separation section to determine the presence of alkyl chains with different carbon numbers within the molecule.

[0062] In the SMS composite nonwoven fabric used as the non-skin side second sheet material 23b, the triglyceride satisfying the above-mentioned (a) and / or the triglyceride satisfying (b) is preferably contained in an amount of 1% by mass or more relative to the fibers containing the triglyceride, from the viewpoint of further improving the barrier properties of the SMS composite nonwoven fabric against liquids, and from the viewpoint of further improving the barrier properties, it is more preferably 2% by mass or more, and even more preferably 3% by mass or more. The ratio of the triglyceride to the triglyceride-containing fiber is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, from the viewpoints of improving spinnability and improving the texture of the SMS composite nonwoven fabric. The ratio of the triglyceride to the triglyceride-containing fiber is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 15% by mass or less.

[0063] One example of a method for incorporating triglyceride into the fibers that make up the SMS composite nonwoven fabric is to melt-knead the thermoplastic resin that makes up the fibers with the triglyceride to incorporate the triglyceride into the thermoplastic resin. However, this method is not limited to this, and other methods may also be used to incorporate triglyceride into the fibers.

[0064] The SMS composite nonwoven fabric may be composed solely of a polyolefin resin and fibers containing the triglycerides described above, or may contain the fibers and other fibers. In the latter case, the SMS composite nonwoven fabric may be composed of a blend of the fibers and other fibers, or may be composed of a laminate of a layer containing only the fibers and a layer containing only other fibers. For example, the SMS composite nonwoven fabric may be composed of a laminate of a meltblown layer containing only the fibers and spunbond layers disposed on each side of the meltblown layer and containing only other fibers. When the SMS composite nonwoven fabric contains the fibers and other fibers, regardless of the form of the SMS composite nonwoven fabric, the proportion of the fibers in the SMS composite nonwoven fabric is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of enhancing the liquid barrier properties of the nonwoven fabric.

[0065] Examples of the absorbent article of the present invention include, but are not limited to, flat-type disposable diapers, pants-type disposable diapers, sanitary napkins, and incontinence pads.

[0066] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to these. For example, in the embodiment shown in Figure 1, the second liquid-immobilizing region 5 may be disposed between the absorbent core 21 and the core wrap sheet material 24.

[0067] Furthermore, in the above embodiment, both the skin-side sheet 22 and the non-skin-side sheet 23 were constructed by stacking multiple sheet materials, but instead, at least one of the skin-side sheet 22 and the non-skin-side sheet 23 may be constructed from a single sheet material.

[0068] In the embodiment shown in Figs. 1 and 2, leakage-barrier cuffs extending in the longitudinal direction may be provided on both longitudinal sides of the surface of the skin-side second sheet material 22b. [Example]

[0069] 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."

[0070] Example 1 In this example, a sanitary napkin having the structure shown in FIG. 2 was manufactured.

[0071] (1) Meltblown nonwoven fabric As a meltblown nonwoven fabric, the basis weight is 15 g / m 2 The meltblown nonwoven fabric was made of polypropylene fibers (hereinafter referred to as "PP fibers") with a fiber diameter of 0.7 μm. The fabric was treated with a fluorine-based water repellent agent, AGE-082 (Asahi Guard, manufactured by AGC Corporation), to impart water repellency, and then dried at 100°C for at least one hour in an electric dryer. The coating amount of the active ingredient of the water repellent agent was 1% by weight of the meltblown nonwoven fabric. The basis weight of the nonwoven fabric was calculated by dividing the average mass of ten 16 cm x 16 cm test pieces randomly taken from the nonwoven fabric by 0.0256.

[0072] (2) Manufacturing of SMS composite nonwoven fabric Each side of this meltblown nonwoven fabric has a basis weight of 9 g / m 2 and spunbond nonwoven fabric made of PP fibers with a fiber diameter of 20 μm are laminated and integrated to form a three-layer structure with a basis weight of 33 g / m 2An SMS composite nonwoven fabric was obtained. This SMS composite nonwoven fabric was used as the non-skin-side second sheet material. The water pressure resistance of this SMS composite nonwoven fabric is shown in Table 1.

[0073] (3) Manufacturing of sanitary napkins An absorbent core was manufactured using a mixed stack of flap pulp and particles of an absorbent polymer made of cross-linked acrylate. The basis weight of the absorbent core was 400 g / m² of pulp in the central part (a region of 90 mm in length and 40 mm in width centered on the excretory area of ​​the wearer). 2 , absorbent polymer 70g / m 2 The surrounding area, excluding the central and high parts, is made of pulp 200g / m 2 , absorbent polymer 35g / m 2 It was decided. The absorbent core was placed so that the non-skin side was facing vertically upward, and powder of absorbent polymer (SAP) was scattered as a liquid immobilizing agent over an area of ​​90 mm in the longitudinal direction and 70 mm in the transverse direction, centered on the excretion point on the non-skin side of the absorbent core, so that the basis weight was as shown in Table 1 below. The absorbent core and the area containing the liquid immobilizing agent were placed over an area of ​​16 g / 2 The absorbent core was covered with a core wrap sheet made of tissue paper, and a non-skin side second sheet material made of the SMS nonwoven fabric obtained in (2) above was placed on the non-skin side of the core wrap sheet. The core wrap sheet was then inverted so that the skin side faced vertically upward, and a skin side second sheet material made of an air-through nonwoven fabric was placed on the skin side of the core wrap sheet. The skin side second sheet material extending from the periphery of the absorbent core was joined to the non-skin side second sheet material to obtain a sanitary napkin having the structure shown in Figure 2.

[0074] Example 2 In Example 1, carboxymethyl cellulose (CMC: molecular weight 1.5 × 10 6 A sanitary napkin was obtained in the same manner as in Example 1 except for this.

[0075] Example 3 As the non-skin side second sheet material, an SMS composite nonwoven fabric prepared as follows was used. (1) Masterbatch manufacturing A propylene homopolymer (MF650X, manufactured by Lyondelbasel, hereinafter referred to as "homo PP"), a propylene random copolymer (Vistamaxx8880, manufactured by Exxonmobil, hereinafter referred to as "random PP"), and triglyceride were weighed out so that the mass ratio was 63 / 27 / 10, and then the mixture was placed in a twin-screw extruder and kneaded to prepare a masterbatch. The triglyceride used was heavily hydrogenated palm oil. This triglyceride was a mixture of several triglycerides, each containing a group derived from saturated fatty acids with different carbon numbers. In this triglyceride, the proportion of groups derived from saturated C14 fatty acids was 1%, the proportion of groups derived from saturated C16 fatty acids was 44%, and the proportion of groups derived from saturated C18 fatty acids was 54%. (2) Manufacturing of SMS composite nonwoven fabric The obtained masterbatch was used as the raw material for the meltblown layer, and was spun and integrated in an SMMS beam-structured facility to produce an SMS composite nonwoven fabric. The fiber diameter of the spunbond layer of the obtained SMS composite nonwoven fabric was 17 μm, and the fiber diameter of the meltblown layer was 2.1 μm. The basis weight of the spunbond layer was 15 g / m 2 The meltblown layer has a weight of 6.5 g / m 2 The basis weight of the SMS composite nonwoven fabric is 21.5 g / m 2 It was. The water pressure resistance of this sheet material is shown in Table 1. In addition, the basis weight of the liquid fixing portion was 200 g / m 2 A sanitary napkin was obtained in the same manner as in Example 1, except that:

[0076] Example 4 In Example 3, the same CMC as in Example 2 was used as the liquid immobilizing agent. Other than this, a sanitary napkin was obtained in the same manner as in Example 3.

[0077] Example 5 In Example 3, xanthan gum (SATIAXANE CX90, manufactured by Unitec Foods Co., Ltd.) was used as the liquid fixative. Other than this, a sanitary napkin was obtained in the same manner as in Example 3.

[0078] Example 6 In Example 3, alginic acid (swelling alginic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the liquid fixing agent. Other than this, a sanitary napkin was obtained in the same manner as in Example 3.

[0079] Comparative Example 1 A sanitary napkin was obtained in the same manner as in Example 1, except that no liquid fixing agent was used.

[0080] Comparative Example 2 A sanitary napkin was obtained in the same manner as in Example 3, except that no liquid fixing agent was used.

[0081] <Evaluation of leak resistance> The sanitary napkins obtained in the Examples and Comparative Examples were placed horizontally with the skin-side sheet facing vertically upward, and an oval injection port (major axis 50 mm, minor axis 23 mm) was placed on the skin-side sheet in this state. 6.0 g of viscosity-adjusted defibered horse blood was injected through the oval injection port and allowed to stand for 1 minute. The defibered horse blood was manufactured by Nippon Biotest Co., Ltd., and its viscosity at a liquid temperature of 25°C was adjusted to 8 cp. The viscosity was measured using a TVB-10M viscometer manufactured by Toki Sangyo Co., Ltd., with a rotor named L / AdP (rotor code 19) at a rotation speed of 12 rpm. The sanitary napkin into which the fiber-removed horse blood had been injected was attached to the movable female waist model shown in Figure 8 of JP-A-9-187476, and shorts were then worn over it. After the model was made to walk at a speed of 100 steps per minute for one hour, the sanitary napkin was removed and the number of spots where the oozing had occurred on the non-skin-side second sheet material was counted. If the oozing spots were connected in a line, the connected area was counted as one spot.

[0082] <Calculation of the liquid diffusion area of ​​the first sheet material on the non-skin side> After the evaluation of the leakage resistance, the non-skin-side second sheet material was removed from the sanitary napkin using a cold spray. A transparency (A4 size, VF-1300N, transparent, recycled transparency film, manufactured by Kokuyo Co., Ltd.) was placed over the exposed non-skin-side first sheet material in a plan view in the area overlapping with the liquid immobilizing agent, and the liquid diffusion area was imaged. The transparency was then scanned and imported into image software (Image-Pro 6.2J, manufactured by Nippon Roper Co., Ltd.), and the liquid diffusion area was calculated.

[0083] [Table 1]

[0084] As is clear from the results shown in Table 1, the sanitary napkins obtained in the Examples showed a reduced amount of defibered horse blood leaking from the non-skin-side second sheet material compared to the sanitary napkins obtained in the Comparative Examples. Furthermore, the sanitary napkins using CMC, xanthan gum, and alginic acid as liquid fixatives had a smaller liquid diffusion area in the non-skin-side first sheet material than the sanitary napkins using SAP as the liquid fixative, and thus reduced the amount of defibered horse blood leaking from the liquid fixation area. In particular, the sanitary napkins using alginic acid as the liquid fixative had a particularly small liquid diffusion area in the non-skin-side first sheet material, and thus particularly reduced the amount of defibered horse blood leaking from the liquid fixation area. [Explanation of symbols]

[0085] 1. Absorbent articles 21 absorbent core 22 Skin side sheet 22a Skin side first sheet material 22b Skin side second sheet material 23 Non-skin side sheet 23a Non-skin side first sheet material 23b Non-skin side second sheet material 24 Core wrap sheet material 5 Liquid fixation site

Claims

1. The absorbent article has an absorbent core, a skin-side sheet located closer to the skin than the absorbent core, and a non-skin-side sheet consisting of one or more sheet materials located closer to the skin than the absorbent core, the sheet materials constituting the non-skin side sheet are all made of fiber sheets, The sheet material includes the non-skin side sheet made of a spunbond-meltblown-spunbond composite nonwoven fabric, At least a portion of the spunbond-meltblown-spunbond composite nonwoven fabric contains a triglyceride, a region containing a liquid fixative between the absorbent core and the non-skin side sheet, or between adjacent sheet materials in the non-skin side sheet consisting of a plurality of sheet materials; The absorbent article, wherein the liquid fixative comprises at least one selected from carboxymethyl cellulose, xanthan gum, and alginic acid.

2. An absorbent article as described in claim 1, wherein the triglyceride is contained in the meltblown layer of the spunbond-meltblown-spunbond composite nonwoven fabric.

3. The triglyceride is (a) a mixture of a triglyceride containing at least one group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least one group derived from a fatty acid having 18 carbon atoms in one molecule, or 3. The absorbent article according to claim 1 or 2, which is (b) a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

4. 4. The absorbent article according to claim 1, wherein the liquid fixative is alginic acid.

5. The sheet material is composed of a core wrap sheet material covering the entire area of ​​the absorbent core, a non-skin side first sheet material located on the non-skin side of the absorbent core, and a non-skin side second sheet material located on the non-skin side of the non-skin side first sheet material and facing outward when the absorbent article is worn, 5. The absorbent article according to claim 1, wherein the non-skin side second sheet material is the spunbond-meltblown-spunbond composite nonwoven fabric.

6. The non-skin-side sheet is breathable, The absorbent article according to claim 5 , wherein the liquid fixative is disposed so as to abut against the non-skin-side surface of the absorbent core and against the non-skin-side first sheet material.

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