Surface material for absorbent articles

Abstract

To provide a surface material for absorbent articles which has a sufficient antibacterial effect and is unlikely to cause skin rashes. [Solution] The surface material 10 of the absorbent article has a skin side 10a and a non-skin side 10b, and has a first layer 11 and a second layer 12. The first layer is made of a fiber assembly that forms the skin side. The second layer is located closer to the non-skin side than the first layer and is made of a fiber assembly. A first antibacterial agent and a second antibacterial agent are blended into the first layer. A third antibacterial agent is blended into the second layer. The first antibacterial agent and the third antibacterial agent are surfactants. The first antibacterial agent is contained in a first fiber treatment agent of fiber 2 contained in the first layer. The third antibacterial agent is contained in a second fiber treatment agent of fiber 6 contained in the second layer. The second antibacterial agent is a metal oxide antibacterial agent, and is contained in the fiber contained in the first layer. The first antibacterial agent and the third antibacterial agent are more soluble in water than the second antibacterial agent.

Description

[Technical field]

[0001] The present invention relates to a surface material for absorbent articles such as disposable diapers. [Background technology]

[0002] When absorbent articles such as disposable diapers, sanitary napkins, panty liners (discharge sheets), and incontinence pads are worn, skin rashes may occur due to sweating, etc. Therefore, in order to prevent the occurrence of rashes, absorbent articles that use antibacterial agents have been proposed. For example, Patent Documents 1 and 2 describe absorbent articles in which an antibacterial agent is kneaded into the fibers constituting the surface material that comes into contact with the wearer's skin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-55187 A [Patent Document 2] Patent Publication No. 2021-52938 Summary of the Invention [Problem to be solved by the invention]

[0004] In the surface material of absorbent articles using antibacterial agents, sufficient antibacterial effects can be obtained by increasing the amount of the antibacterial agent. However, there is a problem that the antibacterial agent acts not only on bacteria originating from the excretory area that cause skin rashes, but also on normal bacteria that help the skin's barrier function, disrupting the balance of normal bacteria on the skin and making the skin more susceptible to rashes.

[0005] The present invention relates to a surface material for absorbent articles that has sufficient antibacterial effect while being less likely to cause skin rashes. [Means for solving the problem]

[0006] The surface material of the absorbent article according to one embodiment of the present invention has a skin side and a non-skin side. The surface material of the absorbent article has a first layer and a second layer. The first layer is made of a fiber assembly that constitutes the skin side surface. The second layer is located closer to the skin than the first layer, It consists of a fiber aggregate. The first layer contains a first antimicrobial agent and a second antimicrobial agent. A third antimicrobial agent is incorporated into the second layer. The first antibacterial agent and the third antibacterial agent are surfactants. The first antibacterial agent is contained in a first fiber treatment agent for the fibers included in the first layer. The third antibacterial agent is contained in a second fiber treatment agent for the fibers included in the second layer. The second antibacterial agent is a metal oxide antibacterial agent and is contained in the fibers included in the first layer. The first antibacterial agent and the third antibacterial agent have higher solubility in water than the second antibacterial agent.

[0007] An absorbent article according to one embodiment of the present invention includes an absorbent body and a surface material located on the skin side of the absorbent body. The facing has a skin side and a non-skin side. The surface material of the absorbent article has a first layer and a second layer. The first layer is made of a fiber assembly that constitutes the skin side surface. The second layer is located closer to the skin than the first layer, It consists of a fiber aggregate. The first layer contains a first antimicrobial agent and a second antimicrobial agent. A third antimicrobial agent is incorporated into the second layer. The first antibacterial agent and the third antibacterial agent are surfactants. The first antibacterial agent is contained in a first fiber treatment agent for the fibers included in the first layer. The third antibacterial agent is contained in a second fiber treatment agent for the fibers included in the second layer. The second antibacterial agent is a metal oxide antibacterial agent and is contained in the fibers included in the first layer. The first antibacterial agent and the third antibacterial agent have higher solubility in water than the second antibacterial agent. Effect of the Invention

[0008] The surface material of the absorbent article of the present invention has sufficient antibacterial effect and is less likely to cause skin rashes. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a disposable diaper as one embodiment of an absorbent article of the present invention, and is a schematic plan view of the skin side (surface material side) showing the state in which the elastic members of each portion are stretched and spread out flat. [Diagram 2] 2 is a schematic cross-sectional view of the absorbent article taken along line II-II in FIG. 1. [Diagram 3] FIG. 2 is a schematic cross-sectional view showing an enlarged view of a portion of a surface material according to a first embodiment, which constitutes a part of the disposable diaper. [Figure 4] FIG. 2(A) is a schematic cross-sectional view of a first fiber used in the surfacing material of the first and second embodiments, and (B) is a schematic perspective view of the first fiber from which the fiber treatment agent has peeled off. [Diagram 5] FIG. 2 is a schematic cross-sectional view of a second fiber used in the surface material of the first and second embodiments. [Figure 6] FIG. 4 is a schematic cross-sectional view showing an enlarged view of a portion of a surface material according to a second embodiment, which constitutes a part of the disposable diaper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an absorbent article having a surface material of the present invention will be described with reference to the drawings, taking a disposable diaper as an example.

[0011] <Overall composition of disposable diapers> The disposable diaper 1 of this embodiment shown in Fig. 1 is a so-called flat-type disposable diaper. However, the surface material of the present invention is not limited to flat-type disposable diapers, and can also be applied to pants-type disposable diapers, sanitary napkins, panty liners, and incontinence pads. The disposable diaper 1 and each of the components constituting the disposable diaper 1 have a longitudinal direction X corresponding to the front-to-back direction of a wearer, and a transverse direction Y corresponding to the left-to-right direction of the wearer and perpendicular to the longitudinal direction X. Furthermore, the disposable diaper 1 and each of the components constituting the disposable diaper 1 have a thickness direction Z perpendicular to both the longitudinal direction X and the transverse direction Y. In this specification, the "skin side" of each component refers to the side that is closest to the wearer's skin when the disposable diaper is worn. The "non-skin side" of each component refers to the side that is opposite to the skin side of the wearer when the disposable diaper is worn. In addition, with respect to the thickness direction Z, the side that is closest to the wearer's skin when worn may be referred to as the "upper" side, and the side that is closest to the clothing may be referred to as the "lower" side. The disposable diaper 1 will be referred to as diaper 1 hereinafter.

[0012] As shown in FIG. 1, the diaper 1 is divided into a ventral region A located on the ventral side in the longitudinal direction X, a dorsal region B located on the dorsal side in the longitudinal direction X, and a crotch region C located between the ventral region A and the dorsal region B. The back region B includes side portions protruding outward in the lateral direction Y from the crotch region C. Fastening tapes 9 are provided on the side edges of the side portions in the lateral direction Y. Similarly, the abdominal region A includes side portions protruding outward in the lateral direction Y from the crotch region C. A landing tape (not shown) is provided on the non-skin side of the abdominal region A for adhering the fastening tape 9. The landing tape is made of a female member of a mechanical hook-and-loop fastener. The fastening tape 9 has a fastening portion 91 made of a male member of a mechanical hook-and-loop fastener. The crotch region C has leg openings that are narrower inward in the lateral direction Y than the ventral region A and the dorsal region B, and is positioned around the wearer's crotch area, including the urination area and anus, when worn. It should be noted that "when worn" here refers to a state in which the normally expected appropriate wearing position is maintained.

[0013] 1 and 2, the diaper 1 comprises a surface material (top sheet) 10 (30), a back surface material (back sheet) 3, an absorbent 4, side sheets 5, a pair of fastening tapes 9, an intermediate sheet 7, and a leak-proof sheet 8. The diaper 1 has a configuration in which the back surface material 3, the leak-proof sheet 8, the absorbent 4, the intermediate sheet 7, and the surface material 10 (30) are laminated in the thickness direction Z. These components are joined together by known joining means such as a hot melt adhesive.

[0014] The absorbent body 4 extends along the longitudinal direction X, and is disposed between the surface material 10 (30) and the back surface material 3. That is, the absorbent body 4 is disposed on the non-skin side of the surface material 10 (30). The absorbent body 4 absorbs liquid excretions (hereinafter sometimes referred to as "liquid" or "excreted liquid") such as moisture contained in the wearer's urine and feces from the surface on the surface material 10 (30) side, and retains the liquid by diffusing it internally. The absorbent body 4 has an absorbent core 40 and a core wrap sheet 41 . The absorbent core 40 is mainly composed of an absorbent material capable of retaining liquid. Specifically, the absorbent core 40 has a structure in which a hydrophilic fiber stack is supported with an absorbent polymer, or a structure made of only a water-absorbent polymer, or the like. The core wrap sheet 41 covers the absorbent core 40 and has a function of, for example, maintaining the shape of the absorbent core 40. The core wrap sheet 41 is formed of, for example, a thin, soft paper such as tissue paper or a liquid-permeable nonwoven fabric.

[0015] The surface material 10 (30) is disposed so as to come into contact with the wearer's skin when the diaper 1 is worn. The surface material 10 (30) is disposed on the skin side 4a side (upper side in the thickness direction Z) of the absorbent 4, and constitutes, for example, the center in the lateral direction Y of the skin side of the diaper 1. The surface material 10 (30) is configured as a liquid-permeable sheet material, and is formed from a nonwoven fabric made of synthetic or natural fibers, or the like. The facing 10 (30) has a skin side 10a (30a) and a non-skin side 10b (30b). The surface material 10 (30) will be described in detail later.

[0016] An intermediate sheet 7 may be provided between the surface material 10 (30) and the absorbent body 4. Nonwoven fabrics obtained by various manufacturing methods can be used for the intermediate sheet 7. The intermediate sheet 7 is arranged from the viewpoints of improving the permeability of liquid from the surface material 10 (30) to the absorbent body 4 and preventing liquid absorbed by the absorbent body 4 from returning to the surface material 10 (30).

[0017] The back surface material 3 is disposed on the non-skin side (lower in the thickness direction Z) of the absorbent body 4 and, for example, constitutes almost the entire non-skin side of the diaper 1 and constitutes the exterior of the diaper 1 when worn. The back surface material 3 is preferably leak-proof, and is formed, for example, from a sheet material having properties such as low liquid permeability, water vapor permeability, and water repellency.

[0018] The pair of side sheets 5 are disposed on the lateral sides in the lateral direction Y of the surface material 10 (30), and, for example, constitute the lateral sides in the lateral direction Y of the skin side of the diaper 1. The side sheets 5 are desirably leak-proof, and are formed, for example, from a sheet material having properties such as poor liquid permeability, water vapor permeability, and water repellency. The pair of side sheets 5 are disposed such that the central sides in the lateral direction Y overlap the surface material 10 (30), and the lateral sides in the lateral direction Y extend to the outside of the surface material 10 (30) and are joined to the back surface material 3. In the diaper 1, the side sheets 5 have thread-like or strip-like elastic members 50 arranged thereon, thereby forming standing gather forming sheets.

[0019] The leak-proof sheet 8 is made of a liquid-impermeable or liquid-slightly permeable resin film, and covers the skin-facing side of the backing material 3 .

[0020] <Surface material> The surface material 10 of the first embodiment and the surface material 30 of the second embodiment used in the diaper 1 will now be described.

[0021] [First embodiment] The surface material 10 in the first embodiment will be described. (Schematic configuration of surface material 10) 3, the surface material 10 is constructed by laminating a second layer 12 and a first layer 11 formed on the second layer 12. The surface material 10 is a flat surface material in which the skin side surface 10a and the non-skin side surface 10b are flat. In this specification, "flat" means that the surface is flat without any irregularities macroscopically, and the presence of relatively small irregularities that may occur due to the fiber structure is acceptable. For example, irregularities in which the difference between the top of the protrusion and the bottom of the recess in the thickness direction is less than 0.3 mm are acceptable.

[0022] The first layer 11 is composed of a fiber assembly including the first fibers 2. The first layer 11 constitutes the skin side 10a of the surface material 10. The second layer 12 is composed of a fiber assembly including the second fibers 6. The second layer 12 constitutes the non-skin side 10b of the surface material 10.

[0023] The first layer 11 and the second layer 12 each consist of a sheet-like material of a fiber material. As the sheet-like material, various nonwoven fabrics can be used, such as a nonwoven fabric produced by a carding method, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric and a needlepunch nonwoven fabric, or a meltblown nonwoven fabric, a spunlace nonwoven fabric and a needlepunch nonwoven fabric.

[0024] In the surface material 10 of the present embodiment, a first antibacterial agent and a second antibacterial agent are blended in the first layer 11, and a third antibacterial agent is blended in the second layer 12. The second antibacterial agent is indicated by reference numeral 22 in Fig. 4 described later, and will hereinafter be referred to as the second antibacterial agent 22. The first antibacterial agent and the third antibacterial agent are surfactants, and are blended into a fiber treatment agent that treats the fiber surface. The second antibacterial agent 22 is a metal oxide antibacterial agent. The second antibacterial agent 22 is contained in the fiber, and more specifically, is blended by being kneaded into the fiber. In this way, the first antibacterial agent and the third antibacterial agent are blended into the fiber in different ways. Moreover, the surface material 10 has a form in which the antibacterial surfactants (the first antibacterial agent and the third antibacterial agent) are present throughout the thickness direction Z of the surface material 10.

[0025] In Fig. 3 and Fig. 6 showing a surfacing material 30 of a second embodiment described later, the second fibers 6 constituting the second layer 12 are shown as lines with white outlines inside. The first fibers 2 constituting the first layer 11 are shown as lines with filled-in interiors. In Figs. 3 and 6, small circles with white outlines inside and small circles with black interiors both diagrammatically show fusion zones between fibers.

[0026] (First layer configuration) As discussed above, the first layer 11 contains a first antimicrobial agent and a second antimicrobial agent 22 . The first antibacterial agent is an antibacterial surfactant. The first antibacterial agent is blended into a first fiber treatment agent used for surface treatment of the first fiber 2. The first fiber treatment agent is indicated by reference numeral 21 in Fig. 4 described later, and hereinafter referred to as the first fiber treatment agent 21. The first fiber treatment agent 21 is used to impart hydrophilicity to the fiber surface. The second antibacterial agent 22 is a metal oxide antibacterial agent, and is kneaded into the first fibers 2 . The first antibacterial agent which is an antibacterial surfactant, the first fiber treatment agent 21 which contains the first antibacterial agent, the second antibacterial agent 22 which is a metal oxide, and the structure of the first fiber 2 will be described later.

[0027] In this embodiment, an example is given in which the first antibacterial agent and the second antibacterial agent are blended in one fiber (first fiber 2), but the present invention is not limited to this embodiment. At least the first layer 11 needs to contain the first antibacterial agent made of an antibacterial surfactant blended in a fiber treatment agent, and the second antibacterial agent 22 blended and kneaded into the fiber. For example, the first layer 11 may contain two types of fibers, one of which contains only the first antibacterial agent and the other of which contains only the second antibacterial agent. More specifically, one of the fibers may be surface-treated with a fiber treatment agent containing the first antibacterial agent and not kneaded with the second antibacterial agent, and the other fiber may be surface-treated with a fiber treatment agent not containing an antibacterial agent and kneaded with the second antibacterial agent.

[0028] The first layer 11 may be configured to include fibers that do not contain any antibacterial agents, such as the first antibacterial agent and the second antibacterial agent.

[0029] (Second layer configuration) The second layer 12 contains a third antibacterial agent. The third antibacterial agent is an antibacterial surfactant. The third antibacterial agent is blended into a second fiber treatment agent used for surface treatment of the second fibers 6. The second fiber treatment agent is indicated by reference numeral 63 in FIG. 5 described later, and hereinafter referred to as the second fiber treatment agent 63. The second fiber treatment agent 63 is used to impart hydrophilicity to the fiber surface. The third antibacterial agent, which is an antibacterial surfactant, the second fiber treatment agent 63 containing the third antibacterial agent, and the structure of the second fibers 6 will be described later.

[0030] The second layer 12 may or may not contain a metal oxide antibacterial agent kneaded into the fibers, but it is more preferable that the second layer 12 does not contain a metal oxide antibacterial agent. Since the fibers contained in the second layer 12 do not contain a metal oxide antibacterial agent, the amount of antibacterial agent in the entire surface material 10 can be reduced, making it easier to maintain a good balance of bacteria normally present on the skin, and suppressing skin rashes.

[0031] In this embodiment, an example is given in which the second layer 12 is composed only of the second fibers 6 containing a third antibacterial agent, but the second layer 12 may also be composed of fibers that do not contain an antibacterial agent.

[0032] (Relationship between the solubility of the first, second and third antibacterial agents in water) The solubility of each antibacterial agent in water can be compared based on the solubility measured by the solubility measurement method described below. Hereinafter, "solubility in water" will be referred to as "water solubility".

[0033] In the surface material 10, when the solubility of the first antibacterial agent is S1, the solubility of the second antibacterial agent 22 is S2, and the solubility of the third antibacterial agent is S3, the relationship is S1≧S3>S2. In other words, the first and third antibacterial agents made of surfactants have higher water solubility than the second antibacterial agent 22 made of a metal oxide antibacterial agent. The water solubility of the first antibacterial agent is equal to or higher than that of the third antibacterial agent.

[0034] In the surface material 10, the solubility S1 of the first antibacterial agent and the solubility S3 of the third antibacterial agent are greater than the solubility S2 of the second antibacterial agent. In other words, the first antibacterial agent and the third antibacterial agent have relatively high water solubility and are easily dissolved in excreted fluids such as urine among the multiple types of antibacterial agents blended in the surface material 10. For this reason, the antibacterial effect of the first antibacterial agent and the third antibacterial agent is exerted promptly from the early stage of excretion.

[0035] Furthermore, the first fiber treating agent 21 of the first fiber 2 is easily peeled off when excreted liquid is supplied, and is easily transferred together with the excreted liquid, mainly to the absorbent body 4. Therefore, the first antibacterial agent contained in the first fiber treating agent 21 transfers together with the excreted liquid to the absorbent body 4, and suppresses bacterial growth in the absorbent body 4 (antibacterial effect), thereby providing a deodorizing effect. Similarly, the second fiber treating agent 63 of the second fibers 6 is easily peeled off when excreted liquid is supplied, and is easily transferred together with the excreted liquid, mainly to the absorbent body 4. Therefore, the third antibacterial agent contained in the second fiber treating agent 63 transfers together with the excreted liquid to the absorbent body 4, and suppresses bacterial growth in the absorbent body 4 (antibacterial effect), thereby exerting a deodorizing effect. Here, the urine odor becomes stronger due to an increase in phenolic compounds and indoles (putrid urine odor). In this embodiment, the first antibacterial agent and the third antibacterial agent suppress the increase in phenolic compounds and indoles, thereby obtaining a deodorizing effect.

[0036] On the other hand, the second antibacterial agent has relatively low water solubility and therefore tends to exert its antibacterial effect gradually and slowly compared to the first and third antibacterial agents, making it easier for the antibacterial effect to be sustained throughout the entire surface material 10. Here, the detailed structure of the first fibers 2 will be described later, but the first fibers 2 contained in the first layer 11 of the surface material 10 have the second antibacterial agent 22 kneaded into them, and the second antibacterial agent 22 is exposed on the surface before the surface treatment with the first fiber treatment agent 21. The first fibers 2 are configured such that their surfaces are treated with the first fiber treatment agent 21 containing the first antibacterial material. Since the second antibacterial agent 22 is kneaded into the fibers, it is difficult for it to migrate to other layers such as the absorbent body 4, and it is likely to remain in the surface material 10. The first fiber 2 is in a state where the first fiber treating agent 21 disposed on the surface thereof is peeled off by the excretion liquid, and the second antibacterial agent kneaded into the fiber is partially exposed. This makes it easier for the second antibacterial agent to come into contact with excrement such as urine and feces, and the antibacterial effect of the second antibacterial agent is efficiently exerted. Thus, the second antibacterial agent has lower water solubility than the first antibacterial agent and the third antibacterial agent, and in addition, the antibacterial effect is enhanced by the peeling off of the first fiber treatment agent 21 from the first fibers 2. For this reason, the second antibacterial agent 22 exerts its antibacterial effect gradually and slowly over the entire surface material 10 compared to the first antibacterial agent and the third antibacterial agent, making it easier for the antibacterial effect to be sustained over the entire surface material 10. Furthermore, by incorporating the second antibacterial agent 22 in the first layer 11 that can come into direct contact with the wearer's skin, excrement such as urine and feces can come into contact with the second antibacterial agent 22 frequently and efficiently. This inhibits the proliferation of bacteria caused by excrement (antibacterial effect), and inhibits skin troubles. Furthermore, since the second antibacterial agent is kneaded into the fibers and is in a state that makes it easy for it to remain on the surface material 10, it is possible to prevent the second antibacterial agent from migrating to the wearer's skin and upsetting the balance of normal bacteria on the skin.

[0037] In this manner, the surface material 10 uses multiple types of antibacterial agents that differ from each other in terms of water solubility and incorporation into the fibers, such as antibacterial agents (first antibacterial agent and third antibacterial agent) made of an antibacterial surfactant and an antibacterial agent (second antibacterial agent) made of a metal oxide. The second antibacterial agent 22, which has low water solubility and is blended into the first layer 11 that may come into direct contact with the wearer's skin in a form that is likely to remain in the first layer 11, has the characteristic of being able to efficiently come into contact with excrement such as urine and feces, thereby providing a stable and sustained antibacterial effect. The first and third antibacterial agents contained in the first and second fiber treatment agents 21 and 63 contained in the first and second layers 11 and 12 and which are easily transferred to the absorbent body 4 along with excreted liquid while the diaper 1 is being worn, have the characteristics of suppressing bacterial growth in the absorbent body 4 (antibacterial effect) and exerting a deodorizing effect. By using multiple types of antibacterial agents with different water solubility and blending forms with fibers in the surface material 10, each antibacterial agent can be blended efficiently according to its characteristics. This makes it possible to obtain a surface material 10 that can stably exhibit excellent antibacterial effects for a long period of time with an overall small blend amount of antibacterial agent. In addition, by reducing the overall blend amount of antibacterial agent, the antibacterial agent can effectively prevent the balance of normal bacteria on the skin from being disrupted by acting not only on excrement-derived bacteria that cause skin rashes but also on normal bacteria that help the skin's barrier function, thereby obtaining a surface material 10 that is less likely to cause skin rashes. As described above, it is possible to obtain a surface material 10 that has a sufficient antibacterial effect while maintaining a good balance of bacteria normally present on the skin, and is less likely to cause skin rashes.

[0038] Furthermore, in the surface material 10, the first antibacterial agent and the third antibacterial agent are contained in the fiber treatment agent and are likely to migrate to the absorbent body 4 together with excreted liquid, while the second antibacterial agent is in a form that is likely to remain in the surface material 10. This makes it possible to prevent the first, second and third antibacterial agents from migrating to the wearer's skin and upsetting the balance of normal bacteria on the skin, thereby preventing skin troubles. In addition, since the first and third antibacterial agents have higher water solubility than the second antibacterial agent, the antibacterial effects of the first and third antibacterial agents are immediate, whereas the antibacterial effect of the second antibacterial agent is exerted more slowly and gently than the antibacterial effects of the first and third antibacterial agents. As a result, in the diaper 1 having the surface material 10 of this embodiment, the antibacterial effect can be sustained for a long period of time from the early stage of excretion.

[0039] Furthermore, with this configuration, a sufficient antibacterial effect can be obtained without blending an antibacterial agent made of a metal oxide into the fibers contained in the second layer 12, and therefore it is not necessary to blend a metal oxide antibacterial agent into the second layer 12. By not blending a metal oxide antibacterial agent into the second layer 12, the amount of antibacterial agent in the entire surface material 10 can be reduced, the balance of normal bacteria on the skin is easily maintained, and skin rashes can be further suppressed.

[0040] Furthermore, the water solubility of the first antibacterial agent may be equal to or higher than that of the third antibacterial agent, but from the viewpoint of obtaining a longer-lasting antibacterial effect, it is more preferable that the first antibacterial agent has a higher water solubility than the third antibacterial agent. The first antibacterial agent has a higher water solubility than the third antibacterial agent, meaning that the third antibacterial agent is less soluble in excretory fluids than the first antibacterial agent. Therefore, by using a first antibacterial agent that has higher water solubility than the third antibacterial agent blended in the second layer 12, which is located closer to the skin than the first layer 11, in the first layer 11, the antibacterial effect of the first antibacterial agent can be immediately exerted on excretory fluids from the wearer, and the antibacterial effect can be obtained from the initial stage of wearing. Furthermore, by making the water solubility of the first antibacterial agent and the third antibacterial agent different, the antibacterial effect of the third antibacterial agent contained in the second fiber treatment agent 63 transferred to the absorbent body 4 by the excreted liquid is exerted more gradually and gently than that of the first antibacterial agent contained in the first fiber treatment agent 21 transferred to the absorbent body 4 by the excreted liquid, and the antibacterial effect and deodorizing effect are sustained for a longer period of time. In addition, by using antibacterial surfactants (first antibacterial agent and third antibacterial agent) with different water solubilities, the antibacterial effect can be maintained well even if the blended amount of each is small, so that the amount of antibacterial agent in the entire surface material 10 can be adjusted to be small, which makes it easier to maintain a good balance of resident bacteria on the skin and further suppresses skin rashes.

[0041] (Detailed composition of the first fiber) The first fiber 2 contained in the first layer 11 may be, for example, a single fiber made of one type of synthetic resin (thermoplastic resin) or a blend polymer made by mixing two or more types of synthetic resins, or may be a composite fiber. The composite fiber referred to here is a synthetic fiber (thermoplastic fiber) obtained by combining two or more types of synthetic resins with different components using a spinneret and spinning them simultaneously, in which multiple components are each continuous in the length direction of the fiber and bonded to each other within the single fiber. The form of the composite fiber may be a core-sheath type, a side-by-side type, etc.

[0042] The first fibers 2 having the second antibacterial agent 22 kneaded therein can be obtained through a process of spinning a synthetic resin previously kneaded with the second antibacterial agent 22. By kneading the second antibacterial agent 22 made of a metal oxide into the first fibers, the second antibacterial agent 22 is effectively prevented from falling off the fibers, compared to the case where the second antibacterial agent is attached to the fibers by spraying, coating, or the like.

[0043] From the viewpoint of exerting a good antibacterial effect, it is preferable that the metal oxide antibacterial agent (second antibacterial agent) is exposed on the fiber surface of the first fiber 2 before the first fiber treatment agent 21 is applied. Thus, from the viewpoint of efficiently exposing the metal oxide antibacterial agent on the fiber surface, it is particularly preferable that the first fiber 2 is a core-sheath type fiber. In this embodiment, an example in which the first fibers 2 are sheath-core fibers will be given.

[0044] The structure of the first fibers 2, which are sheath-core fibers, will be described with reference to FIG. As shown in FIG. 4, the first fiber 2 has a core portion 2C, a sheath portion 2S, and a first fiber treating agent 21. The first fiber treating agent 21 is applied to the surface of the fiber consisting of the core portion 2C and the sheath portion 2S. The sheath portion 2S is configured by kneading in a second antibacterial agent 22. The sheath portion 2S has a resin portion 20 and the second antibacterial agent 22 blended in the resin portion 20.

[0045] The second antibacterial agent 22 is preferably not blended in the core portion 2C but blended only in the sheath portion 2S. Blending the second antibacterial agent 22 only in the sheath portion 2S makes it easier to expose the second antibacterial agent 22 on the fiber surface with a small blend amount of the second antibacterial agent 22. This allows the second antibacterial agent 22 to come into contact with excrement frequently and efficiently, and the antibacterial effect is efficiently exhibited.

[0046] The core-sheath type fibers that are the raw material fibers may have a core 2C made of PET (polyethylene terephthalate) or PP (polypropylene), a sheath 2S made of PE (polyethylene) kneaded with a second antibacterial agent (zinc oxide), and a core-sheath ratio of 20 / 80 to 80 / 20 by mass. The core-sheath ratio refers to the mass ratio (core / sheath) of the resins that make up the core and the sheath.

[0047] The particle size of the second antibacterial agent 22 made of a metal oxide is appropriately set in consideration of the thickness of the fiber to which the second antibacterial agent 22 is mixed and the ease of kneading the metal oxide antibacterial agent (second antibacterial agent) into the fiber. In general, the average particle size of a metal oxide is determined by the volume cumulative particle size D at a cumulative volume of 50% by volume as measured by a laser diffraction scattering type particle size distribution measurement method. 50 It is expressed as 1.5 μm or more and 7 μm or less.

[0048] From the viewpoint of effectively suppressing bacterial growth in the absorbent 4 from the early stages of urination or defecation while maintaining a good balance of normal bacteria on the skin, the proportion of the first antibacterial agent in the fiber (first fiber 2 in the embodiment) treated with the first fiber treatment agent containing the first antibacterial agent is preferably 0.1 mass% or more, more preferably 0.15 mass% or more, preferably 3.0 mass% or less, more preferably 2.5 mass% or less, preferably 0.1 mass% or more and 3.0 mass% or less, and more preferably 0.15 mass% or more and 2.5 mass% or less. A method for calculating the proportion of the first antibacterial agent in the first fibers 2 will be described later.

[0049] From the viewpoint of achieving an efficient antibacterial effect by frequent contact between the second antibacterial agent 22 and the excretory liquid and maintaining a good balance of normal bacteria on the skin, the proportion of the second antibacterial agent 22 in the core-sheath type first fiber 2 is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, preferably 2.5% by mass or less, more preferably 2.0% by mass or less, preferably 0.05% by mass or more and 2.5% by mass or less, more preferably 0.1% by mass or more and 2.0% by mass or less. A method for calculating the proportion of the second antibacterial agent in the first fiber will be described later. In addition, in the core-sheath first fiber 2, from the viewpoints of obtaining an efficient antibacterial effect by more frequent contact between the second antibacterial agent 22 and excreted liquid and maintaining a good balance of normal bacteria on the skin, it is preferable that the metal oxide antibacterial agent (second antibacterial agent) is contained only in the sheath portion. From the above viewpoints, the proportion of the second antibacterial agent 22 in the sheath portion 2S is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.2% by mass or more and 4.0% by mass or less.

[0050] (Details of the second fiber) The second fibers 6 contained in the second layer 12 may be single fibers made of, for example, one type of synthetic resin (thermoplastic resin) or a blend polymer of two or more types of synthetic resins, or may be composite fibers. The composite fiber referred to here is a synthetic fiber (thermoplastic fiber) obtained by combining two or more types of synthetic resins with different components using a spinneret and spinning them simultaneously, in which multiple components are each continuous in the length direction of the fiber and bonded to each other within the single fiber. The form of the composite fiber may be a core-sheath type, a side-by-side type, etc. In this embodiment, an example in which the second fibers 6 are sheath-core fibers will be given.

[0051] The structure of the second fibers 6, which are sheath-core fibers, will be described with reference to FIG. As shown in FIG. 5, the second fiber 6 has a core portion 6C, a sheath portion 6S, and a second fiber treating agent 63. The second fiber treatment agent 63 is applied to the surface of the fiber consisting of the core portion 6C and the sheath portion 6S. The second fibers 6 do not contain a metal oxide antibacterial agent.

[0052] The core-sheath type fibers that serve as the raw material fibers can have a core 6C made of PET (polyethylene terephthalate) or PP (polypropylene) and a sheath 6S made of PE (polyethylene), with a core-sheath ratio of 20 / 80 to 80 / 20 by mass.

[0053] From the standpoint of suppressing bacterial growth in the absorbent body 4 for a long period of time while maintaining a good balance of normal bacteria on the skin, the proportion of the third antibacterial agent in the fiber (second fiber 6 in the embodiment) treated with the second fiber treatment agent containing the third antibacterial agent is preferably 0.1 mass% or more, more preferably 0.15 mass% or more, preferably 3.0 mass% or less, more preferably 2.5 mass% or less, preferably 0.1 mass% or more and 3.0 mass% or less, and more preferably 0.15 mass% or more and 2.5 mass% or less. The method for calculating the proportion of the third antibacterial agent in the second fiber will be described later.

[0054] (Textile treatment agent) The surfaces of the first fibers 2 contained in the first layer 11 have been subjected to a hydrophilization treatment with a first fiber treatment agent. The surfaces of the second fibers 6 contained in the second layer 12 are hydrophilized with a second fiber treating agent. By treating the fiber surface with a fiber treatment agent, the liquid film formed between the fibers that make up the surface material 10 due to excreted fluid can be easily removed, making it difficult for the excreted fluid to remain between the fibers, thereby providing the wearer with a refreshing, dry feeling.

[0055] The first fiber treatment agent contains a first antibacterial agent (antibacterial surfactant) and may further contain other components for the purposes of imparting initial hydrophilicity, imparting durable hydrophilicity, suppressing static electricity during the carding process, improving fiber convergence, etc. The second fiber treatment agent contains a third antibacterial agent (antibacterial surfactant). The second fiber treatment agent may further contain other components for the purposes of imparting initial hydrophilicity, imparting durable hydrophilicity, suppressing static electricity during the carding process, improving fiber convergence, etc.

[0056] Each of the first antibacterial agent and the third antibacterial agent, which are antibacterial surfactants, may be an anionic, cationic, or nonionic surfactant. In particular, from the viewpoint of irritation to the skin, it is preferable that the surfactant is a nonionic surfactant or an anionic surfactant. As the anionic surfactant, a sulfonic acid type anionic surfactant, a sulfate ester type anionic surfactant, a phosphate ester type anionic surfactant, etc. can be used. In particular, from the viewpoint of antibacterial properties and irritation to the skin, an alkyl phosphate ester salt is preferable. As the nonionic surfactant, an ester type nonionic surfactant, an ether type nonionic surfactant, etc. can be used. In particular, from the viewpoint of antibacterial properties and irritation to the skin, sorbitan fatty acid esters and sucrose fatty acid esters are preferable. As the cationic surfactant, an alkylamine salt type cationic surfactant, a quaternary ammonium salt type cationic surfactant, etc. can be used. In particular, from the viewpoint of antibacterial properties, alkylbenzyldimethylammonium chloride is preferable. The first antibacterial agent and the third antibacterial agent may be surfactants of the same type or different types.

[0057] As described above, the first antibacterial agent and the third antibacterial agent may have the same or different water solubility, but from the standpoint of sustaining the antibacterial effect from the early stage of excretion, it is more preferable that the first antibacterial agent is more soluble in water than the third antibacterial agent, i.e., has higher water solubility. By using different surfactants, the water solubilities of the first antibacterial agent and the third antibacterial agent can be made different.

[0058] For example, when anionic surfactants are used as the first antibacterial agent and the third antibacterial agent, the water solubilities of the first antibacterial agent and the third antibacterial agent can be made different by using alkyl phosphate ester salts having different numbers of carbon atoms as the first antibacterial agent and the third antibacterial agent. Specifically, by making the number of carbon atoms in the alkyl phosphate ester salt used as the first antibacterial agent smaller than the number of carbon atoms in the alkyl phosphate ester salt used as the third antibacterial agent, the water solubility of the first antibacterial agent can be made higher than that of the third antibacterial agent. For example, an alkyl phosphate ester salt having 8 to 12 carbon atoms can be used as the first antibacterial agent, and an alkyl phosphate ester salt having 12 to 18 carbon atoms can be used as the third antibacterial agent.

[0059] Anionic and nonionic surfactants are less irritating to the skin than cationic surfactants. For this reason, when an anionic surfactant or a nonionic surfactant is used for either the first antibacterial agent or the third antibacterial agent, and a cationic surfactant is used for the other, it is preferable to use an anionic surfactant or a nonionic surfactant for the first antibacterial agent blended in the first layer 11 that comes into contact with the wearer's skin, and to use a cationic surfactant for the third antibacterial agent blended in the second layer 12 that is located further from the wearer's skin. Such a configuration can provide a surface material 10 that reduces irritation to the skin and prevents the occurrence of skin troubles. In addition, cationic surfactants tend to have a stronger antibacterial effect than anionic surfactants and nonionic surfactants, and since the third antibacterial agent is incorporated in the second layer 12 which does not directly contact the skin, by using an anionic surfactant or nonionic surfactant as the first antibacterial agent and a cationic surfactant as the third antibacterial agent, it is possible to obtain a high deodorizing effect while reducing irritation to the skin. A more specific embodiment is a surfacing 10 that uses an alkyl phosphate salt as the first antimicrobial agent and benzalkonium chloride as the third antimicrobial agent.

[0060] (Second antibacterial agent) As the second antibacterial agent made of a metal oxide, zinc oxide, silver oxide, aluminum oxide, calcium oxide, magnesium oxide, copper oxide, etc. can be used. These metal oxides may be used alone or in combination of two or more. Among these, it is preferable to use zinc oxide in terms of antibacterial properties, safety, and cost. In this embodiment, zinc oxide is used as the metal oxide antibacterial agent (second antibacterial agent) by way of example. In the surface material 30 of the second embodiment described below, zinc oxide is also used as the antibacterial agent by way of example, and the above antibacterial agents can be used as the metal oxide antibacterial agent in the surface material 30.

[0061] (Method of manufacturing surface material 10) The surface material 10 having flat surfaces on both the skin side and the non-skin side can be manufactured, for example, as follows. A fiber web made of the first fibers 2 and a fiber web made of the second fibers 6, both of which are produced by a known method such as a carding method, are laminated, and this laminate is heat-treated, for example, by using a known air-through processing method, etc. Through such heat treatment, the intersections between the fibers contained in each fiber web are melted and fused, thereby bonding the fibers together, and a nonwoven fabric (surface material 10) is produced.

[0062] [Second embodiment] The surface material 30 in the second embodiment will be described. The same components as those in the above-mentioned embodiments are given the same reference numerals, and the description thereof may be omitted. The surface material 10 in the first embodiment is a flat surface material in which both the skin side and the non-skin side are flat, but is not limited to this, and may be an uneven surface material having uneven surfaces, such as the surface material 30 in this embodiment. This will be described below.

[0063] (Configuration of surface material 30) 6, the surface material 30 is constructed by laminating a second layer 32 and a first layer 31 formed on the second layer 32. The surface material 30 is an uneven surface material in which the skin side surface 30a is an uneven surface and the non-skin side surface 30b is a flat surface.

[0064] The first layer 31 is composed of a fiber assembly including the first fibers 2. The first layer 31 constitutes the skin side surface 30a of the surface material 30. The skin side surface 30a is an uneven surface having a plurality of protrusions 33 and a plurality of recesses 34 provided thereon. The second layer 32 is composed of a fiber assembly including the second fibers 6. The second layer 32 constitutes the non-skin side 30b of the surface material 30. The non-skin side 30b is a flat surface.

[0065] The first layer 31 and the second layer 32 each consist of a sheet-like material of a fiber material. As the sheet-like material, various nonwoven fabrics can be used, such as a nonwoven fabric produced by a carding method, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric and a needlepunch nonwoven fabric, or a meltblown nonwoven fabric, a spunlace nonwoven fabric and a needlepunch nonwoven fabric.

[0066] In the diaper 1 equipped with the surface material 30, the skin side 30a of the surface material 30 that comes into contact with the wearer's skin is an uneven surface, so that when worn, the surface material 30, more specifically the tops of the convex portions 33 and the areas nearby, are easily brought into contact with the skin, thereby reducing the stickiness and stuffiness caused by the skin side 30a of the surface material 30 coming into contact with the skin over its entire surface, as well as the irritation caused by chafing.

[0067] 6, the surface material 30 has on its skin side surface 30a a plurality of recesses 34 and a plurality of protrusions 33. A plurality of protrusions 33 are formed on one surface of the skin side surface 30a. Between the protrusions 33, recesses 34 are formed that are recessed toward the non-skin side surface 30b. The plurality of protrusions 33 are formed, for example, in a staggered pattern. The plurality of recesses 34 are also formed in a staggered pattern. The shapes and arrangements of the protrusions 33 and recesses 34 are not particularly limited.

[0068] The recess 34 is formed by bonding the first layer 31 and the second layer 32 together through partial compression to compress the fibers. The compression in the recess 34 may be performed using a method involving melting the fiber material constituting the surface material 30, or may be performed using a method not involving melting the fiber material. Specific examples of compression processes involving melting the fiber material include known embossing processes such as embossing with heat and ultrasonic embossing, and the recess 34 is also referred to as an embossed portion.

[0069] As shown in Fig. 6, the convex portions 33 are located between the multiple concave portions 34. The convex portions 33 have a flat portion of the second layer 32 and a portion of the first layer 31 that protrudes in a dome shape toward the wearer's skin when the diaper 1 is completed. In the surface material 30 of this embodiment, the inside of the convex portions 33 is hollow, making the convex portions 33 hollow. The hollow portion inside the convex portions 33 is called a hollow portion 35. The hollow portion 35 is formed by being surrounded by the non-skin side 31b of the first layer 31 and the skin side 32a of the second layer 32.

[0070] In the surface material 30 of this embodiment, similarly to the surface material 10 of the first embodiment, the first layer 31 contains a first antibacterial agent and a second antibacterial agent 22, and the second layer 32 contains a third antibacterial agent. The first antibacterial agent and the third antibacterial agent are surfactants, and are respectively blended into the first fiber treatment agent 21 and the second fiber treatment agent 63 that treat the fiber surface. The second antibacterial agent 22 is a metal oxide antibacterial agent. The second antibacterial agent 22 is contained in the fibers, and more specifically, is blended by being kneaded into the fibers. In this way, the first antibacterial agent and the third antibacterial agent are blended into the fibers in different ways. The first fibers 2 used in the first layer 31 and the second fibers 6 used in the second layer 32 have the same configuration as the first fibers 2 and the second fibers 6 described in the first embodiment, and therefore a description thereof will be omitted here. In addition, the water solubility of the first antibacterial agent, the second antibacterial agent, and the third antibacterial agent is also the same as in the first embodiment.

[0071] As in the first embodiment, the surface material 30 uses multiple types of antibacterial agents that differ in water solubility and incorporation into the fibers, such as antibacterial agents (first antibacterial agent and third antibacterial agent) made of an antibacterial surfactant and an antibacterial agent (second antibacterial agent) made of a metal oxide. In this way, by using multiple types of antibacterial agents with different water solubility and blending forms with fibers in the surface material 30, each antibacterial agent can be blended efficiently according to its characteristics. This makes it possible to obtain a surface material 30 that can stably exhibit excellent antibacterial effects for a long period of time with an overall small amount of antibacterial agent blended. In addition, by reducing the overall amount of antibacterial agent blended, it is possible to effectively prevent the antibacterial agent from acting not only on excrement-derived bacteria that cause skin rashes but also on resident bacteria that help the skin's barrier function, thereby disrupting the balance of resident bacteria on the skin, and thus to obtain a surface material 30 that is less likely to cause skin rashes. As described above, it is possible to obtain a surface material 30 that has a sufficient antibacterial effect while maintaining a good balance of bacteria normally present on the skin, making it less likely to cause skin rashes.

[0072] The surface material 30 has an uneven structure, and therefore the distance between the wearer's skin in contact with the tops of the convex portions 33 of the first layer 31 and the second layer 32 can be set longer, compared to the surface material 10 of the first embodiment, which has a flat structure on both sides. For this reason, it is possible to expand the range of antibacterial agent material choices, for example by using an antibacterial agent that is highly irritating to the skin but has a high antibacterial effect as the antibacterial agent used in the second layer 32, and it is possible to achieve a configuration that improves the antibacterial effect while further suppressing irritation to the skin. As an example, an anionic surfactant or a nonionic surfactant can be blended in the first layer 31 as the first antibacterial agent, and the second layer 32 can be blended in the anionic surfactant or a cationic surfactant which is more irritating to the skin than the nonionic surfactant but has a high antibacterial effect as the third antibacterial agent, thereby achieving a high deodorizing effect while reducing irritation to the skin.

[0073] Furthermore, by having the hollow portion 35 in the surface material 30, the excreted liquid passes through the first layer 31, is temporarily stored in the hollow portion 35, and then transfers to the second layer 32. By temporarily storing the excreted liquid in the hollow portion 35, the second antibacterial agent 22, which is formulated to tend to remain in the first layer 31, comes into contact with the excreted liquid more frequently, thereby further improving the antibacterial effect.

[0074] (Example of manufacturing method of surface material 30) An example of a method for manufacturing the surface material 30 will be given below, but the method is not limited to this. The surface material 30, which has an uneven skin side 30a and a flat non-skin side 30b, can be manufactured by overlapping a nonwoven fabric made of the first fibers 2 with a nonwoven fabric made of the second fibers 6 and partially joining these nonwoven fabrics. The nonwoven fabric made of the first fibers 2 constitutes a first layer 31 of the surface material 30 . The nonwoven fabric made of the second fibers 6 constitutes the second layer 32 of the surface material 30 .

[0075] As an example of the manufacturing method, the manufacturing method described in JP-A-2004-174234 can be used. That is, the sheet-like material of the nonwoven fabric to be the first layer 31 is intermittently stretched and processed to have unevenness by being interlocked between two gear rolls having uneven surfaces. In the sheet-like material processed to have unevenness in this way, the stretched parts form the convex parts 33. On the other hand, the non-stretched parts form the concave parts 34 when the surface material 30 is made. The sheet-like material to be the first layer 31 having the multiple convex parts 33 formed thereon is superimposed on the sheet-like material to be the second layer 32, and the superimposed material is pressed between two rolls, at least one of which is heated to a predetermined temperature, to be partially bonded. As a result, the first layer 31 and the second layer 32 are compressed and partially bonded by heat fusion, and the surface material 30 having an uneven structure is manufactured. The surface of the surface material 30 facing the first layer 31 (skin side 30a) has unevenness, and the surface of the surface material 30 facing the second layer 32 (non-skin side 30b) is almost flat.

[0076] <Supplementary explanation>

[0077] [Examples of solubility of each antibacterial agent in water] The water solubilities S1 to S3 of the first to third antibacterial agents shown below are calculated by the solubility measurement method described below.

[0078] From the viewpoint of making it difficult for the second antibacterial agent 22 to migrate to other layers by excreted liquid, realizing efficient contact between the second antibacterial agent (metal oxide antibacterial agent) and excreta in the surface material 10 (or surface material 30), and preventing skin rash due to excreta such as stool for a long period of time, the second antibacterial agent 22 is preferably poorly soluble in water or insoluble in water. In other words, it is preferable that the water solubility of the second antibacterial agent 22 is low. Specifically, the solubility S2 of the second antibacterial agent 22 is preferably 0.01 g / 100 ml or more and 0.5 g / 100 ml or less, more preferably 0.03 g / 100 ml or more and 0.3 g / 100 ml or less, and even more preferably 0.05 g / 100 ml or more and 0.2 g / 100 ml or less.

[0079] In order to achieve an even more pronounced effect of suppressing bacterial growth in the absorbent 4 over a long period of time, it is preferable that the first antibacterial agent (antibacterial surfactant) and the third antibacterial agent (antibacterial surfactant) have different solubilities, and the difference between the solubility S1 of the first antibacterial agent and the solubility S3 of the third antibacterial agent is preferably 0.2 g / 100 ml or more, more preferably 0.4 g / 100 ml or more, and even more preferably 0.6 g / 100 ml or more.

[0080] From the viewpoint of quickly suppressing bacterial growth in the absorbent 4 from the initial stage of urination or defecation, the solubility S1 of the first antibacterial agent is preferably 1 g / 100 ml or more and 5 g / 100 ml or less, more preferably 1.5 g / 100 ml or more and 4.5 g / 100 ml or less, and even more preferably 2.0 g / 100 ml or more and 4.0 g / 100 ml or less.

[0081] From the viewpoint of suppressing bacterial growth in the absorbent body 4 for a long period of time, the solubility S3 of the third antibacterial agent is preferably 1 g / 100 ml or more and 5 g / 100 ml or less, more preferably 1.5 g / 100 ml or more and 4.5 g / 100 ml or less, and even more preferably 2.0 g / 100 ml or more and 4.0 g / 100 ml or less.

[0082] (Method for measuring the solubility of antibacterial agents) Add 5 g of the antibacterial agent to 100 ml of water and stir at 300 rpm for 30 minutes at room temperature (25° C.). Separately, measure the mass of the filter paper and use the measured mass as the initial mass of the filter paper. The stirred solution is filtered using the filter paper whose mass has been measured, and the filter paper is dried in a dryer at 40°C for 2 hours. The mass of the dried filter paper is measured, and the measured mass is regarded as the dried mass of the filter paper. The solubility is then calculated using the following formula. Solubility (g) = 5 (g) - {(mass of dried filter paper) (g) - (initial mass of filter paper) (g)} A higher solubility calculated in this manner indicates a higher water solubility, and a lower solubility indicates a lower water solubility.

[0083] [Calculation method for the ratio of the first antibacterial agent (third antibacterial agent) to the first fiber (second fiber)] When the first layer (second layer) is composed only of the first fiber 2 (second fiber 6), the proportion of the first antibacterial agent (third antibacterial agent) consisting of an antibacterial surfactant in the first fiber 2 (second fiber 6) treated with the first fiber treatment agent 21 (second fiber treatment agent 63) containing the first antibacterial agent (third antibacterial agent) can be calculated as follows.

[0084] 300mm from the first (second) layer of surface material 2 Cut out a section of 300 mm or more. 2 If the total area is less than 300 mm, cut out pieces from multiple locations. 2 Then, measure the mass of the slice. The slice is subjected to a multi-stage solvent extraction method using a non-polar solvent to a polar solvent, and the antibacterial agent (antibacterial surfactant) present in the slice is separated to obtain a solution containing a single composition. The obtained solution is dried and solidified, and the chemical structure of the antibacterial agent is identified by a combination of 1H-NMR (nuclear magnetic resonance), IR (infrared spectroscopy), LC (liquid chromatography), GC (gas chromatography), MS (mass spectrometry), GPC (gel permeation chromatography), fluorescent X-rays, etc. In addition, a calibration curve is created by a well-known analytical means such as GC and LC using an antibacterial agent having a specified chemical structure as a standard substance, and the antibacterial agent in the slice is quantified. Based on this quantification result, the mass of the antibacterial agent in the slice is determined. When multiple types of antibacterial agents are present in the slice, the sum of the masses of the various antibacterial agents is calculated, and the sum is regarded as the mass of the antibacterial agent in the slice. Then, the mass of the antibacterial agent in the slice is divided by the mass of the slice, and the result is multiplied by 100 to calculate the proportion of the first antibacterial agent (third antibacterial agent) in the first fiber (second fiber).

[0085] Furthermore, the first layer (second layer) constituting the surface material only needs to contain fibers containing at least an antibacterial agent made of an antibacterial surfactant, and may also contain fibers that do not contain an antibacterial agent made of an antibacterial surfactant.

[0086] [Method to confirm the presence of the second antibacterial agent] Whether the second antibacterial agent (metal oxide antibacterial agent) made of a metal oxide is kneaded into the fibers can be confirmed by cutting the surface material with a razor (e.g., a single-edged razor manufactured by Feather Safety Razor Co., Ltd.) to obtain a test piece and observing the cut surface of the test piece under magnification. For example, the cut surface of the test piece is observed at a magnification of 1000 times using a Hitachi S-4000 field emission scanning electron microscope. Observation of the cut surface confirmed that the second antibacterial agent made of a metal oxide is kneaded into the fibers and is exposed on the surface of the sheath. In addition, from the observation of the cut surface, it is possible to grasp not only the cross-sectional profile of the fiber but also the fiber structure, for example, whether the fiber is a sheath-core type fiber or a single fiber structure. Furthermore, in the case of a sheath-core type fiber, the area ratio of the core and the sheath can be calculated from the observation of the cut surface. Furthermore, when observing the cut surface, by simultaneously photographing objects with known dimensions, it is possible to determine the dimensions of each component, such as the height of the protrusion 33 and the thickness of each layer. Furthermore, by performing SEM-EDX analysis of the fiber cross section, it was possible to confirm that the agent contained in the sheath was zinc oxide (second antibacterial agent).

[0087] [Calculation method for the proportion of the second antibacterial agent in the first fiber] A method for calculating the proportion of the second antibacterial agent (metal oxide antibacterial agent) in the core-sheath fibers (first fibers) will be described. Weigh out 1 g of the fiber to be measured. If it is difficult to cut off 1 g, cut it into a piece of any size and measure its mass. Then, change the amounts of reagents, etc. according to the resulting mass and carry out the following procedure. The cut pieces are chopped as small as possible and placed in a 300 ml beaker, and 200 ml of ion-exchanged water is added to the beaker and stirred with a magnetic stirrer so that the fibers are completely in contact with the water. While stirring the liquid, 3 ml of concentrated hydrochloric acid (about 10 M) is added little by little, and the liquid is stirred for another hour to elute the antibacterial agent present on the surface of the fibers that make up the second layer. Next, 6 ml of 5.1 M sodium hydroxide aqueous solution is added to neutralize the liquid, and then 10 ml of a pH 10.7 buffer solution (containing 54.7 ml of 28 mass % NH3 aqueous solution and 0.535 g of NH4Cl dissolved in ion-exchanged water) is added to fine-tune the pH. Next, Eriochrome Black T reagent (0.125 g of Eriochrome Black T powder and 1.125 g of hydroxylamine hydrochloride dissolved in 25 ml of absolute ethanol) is added as an indicator to turn the liquid pale pink. Titration is performed using 0.0002 M EDTA·2Na as the titrant, and the amount (ml) of titrant added when the liquid changes from pink to pale blue to green is taken as the titration value A. Then, the mass of the antibacterial agent is calculated using the following formula. In the formula below, "5000000" means the volume (ml) of titrant per 1 mol. Mass of antibacterial agent (g) = titration value A × mass per 1 mol of antibacterial agent / 5,000,000 The mass of the antibacterial agent calculated as above is the amount of the second antibacterial agent contained per gram (unit mass) of the fiber (first fiber) to be measured. Therefore, the calculated mass of the second antibacterial agent multiplied by 100 is the proportion of the second antibacterial agent in the core-sheath type first fiber.

[0088] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0089] For example, in the above embodiment, the absorbent article is a disposable diaper, but is not limited thereto. The absorbent article of the present invention may be, for example, a urine pad, a panty liner, a sanitary napkin, etc., and the surface material of the present invention can be used as the surface material of these absorbent articles. Absorbent articles are generally composed of a liquid-permeable surface material, a liquid-impermeable backing material, and a liquid-retentive absorbent interposed between the two sheets.

[0090] Also, for example, in the above embodiment, the surface material is configured with two layers, but it may be configured with three or more layers. In this case, the first layer constituting the skin side of the surface material contains a first antibacterial agent made of an antibacterial surfactant and a second antibacterial agent made of a metal oxide antibacterial agent kneaded into the fibers, and the second layer located on the non-skin side of the first layer contains a third antibacterial agent made of an antibacterial surfactant. For example, the surface material may be configured such that another layer is interposed between the first layer and the second layer, or such that the first layer, the second layer, and another layer are located in this order from the skin side to the non-skin side.

[0091] Furthermore, for example, in the surface material 30 of the second embodiment described above, the protrusions 33 have a hollow structure, but may have a solid structure.

[0092] Furthermore, each of the first fibers and the second fibers in each of the above-described embodiments may further contain an antibacterial agent such as an organic compound other than the first to third antibacterial agents.

[0093] The antibacterial agent-containing fiber may also contain a skin care agent. As the skin care agent, a hydrophobic skin care agent, a hydrophilic skin care agent, etc. can be used.

[0094] A hydrophobic skin care agent is a hydrophobic component that is not water-soluble or water-dispersible or has extremely low solubility, and is a composition or compound that has protective, healing, etc. effects on the wearer's skin. More specifically, a hydrophobic component is one that dissolves in an amount of less than 1 g when 10 g of the component is mixed in 1 L of ion-exchanged water and left to stand for 24 hours, preferably one that dissolves in an amount of 0.1 g or less, and particularly preferably one that does not dissolve at all. Examples of hydrophobic skin care agents include fatty acids with a carbon chain length of 12 to 28 or ester compounds of the fatty acids and glycerin, wax, petrolatum, etc., and in particular, it is preferable to contain unsaturated fatty acids with a carbon chain length difference of 12 to 28 or glycerin ester compounds of the unsaturated fatty acids. The glycerin ester is a monoester, diester, or triester of glycerin and the above-mentioned unsaturated fatty acid, and in particular, it is preferable to use a triester. As agents containing fatty acids or fatty acid compounds, natural product extracts such as argan oil and shea butter can be preferably used. In particular, argan oil, which is a hydrophobic vegetable oil containing unsaturated fatty acids, maintains the balance between moisture and oil in the skin, prevents dryness, and functions as a skin care agent. In addition, argan oil contains a lot of unsaturated fatty acids such as oleic acid and linoleic acid, and has a strong ability to remove active oxygen, and can reduce skin damage caused by, for example, sunburn.

[0095] On the other hand, a hydrophilic skin care agent is a hydrophilic component that is water-soluble or water-dispersible, and is preferably capable of suppressing the occurrence of rash or inflammation, and, if rash or inflammation occurs, suppressing the progression of the rash or inflammation or alleviating the rash or inflammation. More specifically, a hydrophilic component is one that dissolves or disperses in an amount of 1 g or more when 10 g of the component is mixed in 1 L of ion-exchanged water and left to stand for 24 hours, preferably one that dissolves or disperses in an amount of 5 g or more, more preferably one that dissolves in an amount of 1 g or more, even more preferably one that dissolves in an amount of 5 g or more, and most preferably one that dissolves completely. As the hydrophilic skin care agent, natural product extracts such as peach leaf extract and witch hazel extract, polyhydric alcohols having 2 to 4 carbon chains, polyethylene glycol, hydrophilic compounds having skin care functions, etc. can be used. Among these, peach leaf extract (hydrophilic extract), which is a plant extract, is preferred because it has antibacterial and anti-inflammatory properties. The peach leaf extract, which is a hydrophilic component, dissolves in the liquid supplied to the surface material and transfers to the skin, providing a skin care effect. A polyhydric alcohol having 2 to 4 carbon chains is a hydrophilic component, typically 1,3-butylene glycol. The use of 1,3-butylene glycol improves moisturizing effect and lubricity. The improved lubricity reduces friction between the skin and the nonwoven fabric, suppressing damage to the skin. 1,3-butylene glycol is a moisturizing liquid water-soluble base component that has a smooth feel and is less sticky, and keeps the skin moist. 1,3-butylene glycol is used as a moisturizing agent and also as a solvent. For example, when peach leaf extract is used as a skin care agent, 1,3-butylene glycol can be used as a solvent for peach leaf extract. Here, 1,3-butylene glycol is taken as an example, but any polyhydric alcohol having 2 to 4 carbon chains will have the same effect, and for example, propylene glycol may be used. Propylene glycol can also be used as an extraction solvent for peach leaf extract (hydrophilic extract).

[0096] The present invention can also be configured as follows. <1> A surface material for an absorbent article having a skin side and a non-skin side, a first layer made of a fiber aggregate constituting the skin side surface, and a second layer made of a fiber aggregate located on the non-skin side of the first layer, The first layer contains a first antibacterial agent and a second antibacterial agent, and the second layer contains a third antibacterial agent; the first antibacterial agent and the third antibacterial agent are surfactants, the first antibacterial agent is contained in a first fiber treatment agent for fibers included in the first layer, and the third antibacterial agent is contained in a second fiber treatment agent for fibers included in the second layer; the second antibacterial agent is a metal oxide antibacterial agent and is contained in the fibers included in the first layer; The first antibacterial agent and the third antibacterial agent have higher solubility in water than the second antibacterial agent. Surface material for absorbent articles. <2> The metal oxide antibacterial agent is incorporated into the fibers of the first layer. The above <1> A surface material for an absorbent article according to claim 1. <3> A ratio of the first antibacterial agent in the fiber treated with the first fiber treatment agent containing the first antibacterial agent is preferably 0.1% by mass or more and 3.0% by mass or less, and more preferably 0.15% by mass or more and 2.5% by mass or less, The ratio of the third antibacterial agent in the fiber treated with the second fiber treatment agent containing the third antibacterial agent is preferably 0.1% by mass or more and 3.0% by mass or less, and more preferably 0.15% by mass or more and 2.5% by mass or less. The above <1> or <2> A surface material for an absorbent article according to claim 1. <4> The first antimicrobial agent is more soluble in water than the third antimicrobial agent. The above <1> from <3> 13. A surface material for an absorbent article according to any one of claims 1 to 12. <5> The solubility of the first antibacterial agent in water is preferably 1 g / 100 ml or more and 5 g / 100 ml or less, more preferably 1.5 g / 100 ml or more and 4.5 g / 100 ml or less, and even more preferably 2.0 g / 100 ml or more and 4.0 g / 100 ml or less, The solubility of the third antibacterial agent in water is preferably 1 g / 100 ml or more and 5 g / 100 ml or less, more preferably 1.5 g / 100 ml or more and 4.5 g / 100 ml or less, and even more preferably 2.0 g / 100 ml or more and 4.0 g / 100 ml or less. The above <4> The surface material of the absorbent article according to claim 1. <6> The difference between the solubility in water of the first antibacterial agent and the solubility in water of the third antibacterial agent is preferably 0.2 g / 100 ml or more, more preferably 0.4 g / 100 ml or more, and even more preferably 0.6 g / 100 ml or more. The above <4> or <5> The surface material of the absorbent article according to claim 1. <7> The solubility of the second antibacterial agent in water is preferably 0.01 g / 100 ml or more and 0.5 g / 100 ml or less, more preferably 0.03 g / 100 ml or more and 0.3 g / 100 ml or less, and even more preferably 0.05 g / 100 ml or more and 0.2 g / 100 ml or less. The above <1> from <6> 13. A surface material for an absorbent article according to any one of claims 1 to 12. <8> The fiber containing the second antibacterial agent is a core-sheath type fiber having a core and a sheath, the second antibacterial agent is blended only in the sheath, and the second antibacterial agent is exposed on the fiber surface. The above <1> from <7> 13. A surface material for an absorbent article according to any one of claims 1 to 12. <9> The proportion of the second antibacterial agent in the core-sheath fiber is preferably 0.05% by mass or more and 2.5% by mass or less, and more preferably 0.1% by mass or more and 2.0% by mass or less. The above <8> A surface material for an absorbent article according to claim 1. <10> The second antimicrobial agent is zinc oxide. The above <1> from <9> 13. A surface material for an absorbent article according to any one of claims 1 to 12. <11> The second layer does not include a metal oxide antimicrobial agent. The above <1> from <10> 13. A surface material for an absorbent article according to any one of claims 1 to 12. <12> The skin side surface is an uneven surface. The above <1> from <11> 13. A surface material for an absorbent article according to any one of claims 1 to 12. <13> An absorber; The absorbent body is located on the skin side. <1> from <12> The surface material according to any one of the above. An absorbent article comprising: [Explanation of symbols]

[0097] 1...Disposable diapers (absorbent articles) 2...First fiber 6…Second fiber 10, 30...Surface material (surface material of absorbent article) 11, 31…1st layer 12, 32…2nd layer 21...First fiber treatment agent 22...Second antibacterial agent 63...Second fiber treatment agent

Claims

1. A surface material for an absorbent article having a skin side and a non-skin side, a first layer made of a fiber aggregate constituting the skin side surface, and a second layer made of a fiber aggregate located on the non-skin side of the first layer, The first layer contains a first antibacterial agent and a second antibacterial agent, and the second layer contains a third antibacterial agent; the first antibacterial agent and the third antibacterial agent are surfactants, the first antibacterial agent is contained in a first fiber treatment agent for fibers included in the first layer, and the third antibacterial agent is contained in a second fiber treatment agent for fibers included in the second layer; the second antibacterial agent is a metal oxide antibacterial agent and is contained in the fibers included in the first layer; The first antibacterial agent and the third antibacterial agent have higher solubility in water than the second antibacterial agent. Surface material for absorbent articles.

2. The metal oxide antibacterial agent is incorporated into the fibers of the first layer. The surface material of the absorbent article according to claim 1.

3. a ratio of the first antibacterial agent in the fiber treated with the first fiber treatment agent containing the first antibacterial agent is 0.1% by mass or more and 3.0% by mass or less; The ratio of the third antibacterial agent in the fiber treated with the second fiber treatment agent containing the third antibacterial agent is 0.1% by mass or more and 3.0% by mass or less. A surface material for an absorbent article according to claim 1 or 2.

4. The first antibacterial agent is more soluble in water than the third antibacterial agent. A surface material for an absorbent article according to claim 1 or 2.

5. The fiber containing the second antibacterial agent is a core-sheath type fiber having a core and a sheath, the second antibacterial agent is blended only in the sheath, and the second antibacterial agent is exposed on the fiber surface. A surface material for an absorbent article according to claim 1 or 2.

6. The ratio of the second antibacterial agent in the core-sheath fiber is 0.05% by mass or more and 2.5% by mass or less. A surface material for an absorbent article according to claim 5.

7. The second antimicrobial agent is zinc oxide. A surface material for an absorbent article according to claim 1 or 2.

8. The second layer does not include a metal oxide antimicrobial agent. A surface material for an absorbent article according to claim 1 or 2.

9. The skin side surface is an uneven surface. A surface material for an absorbent article according to claim 1 or 2.

10. An absorber; The surface material according to claim 1 or 2, which is located on the skin side of the absorbent body. An absorbent article comprising:

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