TWI778276B - Liquid-permeable sheet for absorbent articles - Google Patents

Abstract

An object of the present invention is to provide a liquid-permeable sheet for an absorbent article which is excellent in liquid permeability, has desired sheet strength, and can suppress moisture regain. A liquid-permeable sheet (11) for an absorbent article (10) is provided with: a fabric (40) having a first surface (40a) and a second surface (40b) facing each other in the thickness direction (Z); and The fiber web (50) is integrated with the first surface (40a) of the fabric (40) by entanglement. The constituent threads (41) of the fabric (40) are formed of cellulose fibers, and the fiber web (50) The constituent fibers (51) are substantially the same surface as the second surface (40b) of the woven fabric (40), or extend outward in the thickness direction.

Description

Liquid-permeable sheet for absorbent articles

The present invention relates to a liquid-permeable sheet for an absorbent article, and more specifically, to a slightly incontinent pad, a panty liner, a sanitary napkin, a secretion absorbing pad, a urine absorbing pad, an adult and Liquid-permeable sheet for absorbent articles such as disposable diapers for children.

Conventionally, the liquid-permeable sheet for absorbent articles is known. For example, Patent Document 1 discloses an absorbent article provided with a topsheet located on the opposing surface side of the absorber. In the surface sheet, a plurality of openings penetrating in the thickness direction are formed. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 8-246321

In the absorbent article disclosed in Patent Document 1, since the surface sheet has a plurality of openings, bodily fluids can be rapidly transferred from the skin-opposing surface of the absorbent article to the absorber.

[The problem to be solved by the invention]

(The problem of the first invention) However, since the surface sheet is formed with a plurality of openings, the strength of the sheet is low, and there is a risk of curling or partial breakage during wearing. Moreover, there exists a possibility that the bodily fluid absorbed by the absorber may flow back (Rewet back) toward the surface side of the top sheet through the opening.

The first invention is an improvement of the conventional invention, and its subject is to provide a liquid-permeable sheet for an absorbent article which is excellent in liquid permeability and has required sheet strength and can suppress backflow.

(The problem of the second invention) The top sheet of Patent Document 1 is formed with a plurality of openings, so that the sheet strength is low, and there is a possibility of curling or partial breakage during wearing. In addition, since it is formed of hydrophilic fibers, the hydrophilic fibers absorb menstrual blood and swell, and the strength of the sheet is further weakened. Therefore, it is impossible to scrape the menstrual blood adhering to the skin at the opening of the surface sheet. In addition, in order to prevent the occurrence of the defect, when the surface sheet is formed of the hydrophobic fiber, the body fluid cannot be sufficiently absorbed.

In addition, since the sheet strength of the surface sheet is low, when the sanitary napkin is taken out from the individual packaging bag accommodated in the folded state, creases are easily formed, and when the sanitary napkin is attached to the underwear, a part of the creases are easily formed. Floating from the underwear may cause lateral leakage of menstrual blood and deterioration of wearing feeling.

The 2nd invention is an improvement of the conventional invention, and its subject is to provide the liquid-permeable sheet for absorbent articles which is excellent in liquid permeability, has required sheet strength, and can suppress moisture regain. [means to solve the problem]

In the first invention, a liquid-permeable sheet for an absorbent article includes: a woven fabric having a first surface and a second surface facing each other in the thickness direction; and a fiber web that is intertwined with A fiber web in which the first side of the fabric is integrated, the constituent threads of the fabric are formed of cellulose fibers, and the constituent fibers of the fiber web are substantially the same side as the second side of the fabric, or more toward it. The outer extension in the thickness direction is present.

In the second invention, a liquid-permeable sheet for an absorbent article is provided, comprising: a woven fabric having a first surface and a second surface facing each other in the thickness direction; and a fiber web that is intertwined with The first surface of the fabric is integrated with the fiber web, the constituting threads of the fabric are formed of continuous twisted yarns composed of cellulose fibers, and the fiber web is composed of hydrophilic fibers and hydrophobic fibers. [Inventive effect]

The liquid-permeable sheet for an absorbent article of the first invention has a surface sheet that has a skin-like feel like a cloth, and can achieve a good absorption rate of bodily fluids and suppress moisture regain. The liquid-permeable sheet for an absorbent article of the second invention has a surface sheet that has a cloth-like feel to the skin, has good excrement scraping properties, and is less likely to form creases, thereby suppressing lateral leakage of bodily fluids and reducing wearing comfort.

(1st invention)

The following embodiment includes not only the structure indispensable to the invention but also the optional and ideal structure about the absorbent article shown in the drawing. Hereinafter, an embodiment of the sanitary napkin 10 which is an example of the absorbent article of the present invention will be described with reference to the drawings. The sanitary napkin 10 has a vertical direction Y, a horizontal direction X, and a thickness direction Z.

As shown in FIGS. 1 to 3 , the sanitary napkin 10 has a vertical centerline P that bisects the dimension in the width direction and a horizontal centerline Q that bisects the dimension of the longitudinal dimension, and includes: a skin-facing surface The non-skin facing surface (outer surface) side on the (inner surface) side and the opposite side; the convexly curved first and second end edges 10a, 10b; in the central part where the transverse center line Q exists, the convexly curved first and second end edges 10a and 10b are formed. 1 and 2 side edges 10c, 10d; the liquid-permeable surface sheet 11 on the skin-opposite side; the liquid-impermeable back sheet 12 on the non-skin-opposite side; and between these two sheets 11, 12 The liquid-absorbent absorber 20. The surface sheet 11 and the absorber 20 are joined to each other by a conventional joining means such as a hot melt adhesive to form the liquid absorbing layer 13 .

In addition, although not shown, in order to improve the softness of the sanitary napkin 10, between the surface sheet (liquid-permeable sheet) 11 and the absorber 20, an intermediate sheet made of nonwoven fabric with high bulkiness may be arranged. In addition, between the absorber 20 and the back sheet 12, in order to suppress leakage of bodily fluids, a leak-proof sheet preferably made of a non-woven fabric or a plastic film having air permeability and liquid impermeability may be arranged.

The absorber 20 has a first edge 20a facing the first edge 10a, a second edge 20b facing the second edge 10b, and between the first and second edge 20a, 20b, The first and second side edges 20c and 20d extending in the vertical direction Y. The front and back sheets 11 and 12 extend outward from the outer periphery of the absorber 20, and on the skin-opposing surface side of the top sheet 11, a pair extending in the longitudinal direction Y is arranged so as to face each other in the lateral direction X. Side lamella 14 . The pair of side sheets 14 are joined to the top sheet 11 via a conventional adhesive means or a side joining portion (not shown) formed by a welding means. Although not shown, in the side sheet 14, in order to form a leak-proof wall standing up toward the body side in the wearing state, the elastic material extending in the longitudinal direction Y may be arranged so as to be retractable in the extended state. In addition, the side joint portion for fixing the side sheet 14 may be a seal line extending in the vertical direction Y having design elements such as floral patterns and geometric patterns.

The sanitary napkin 10 has a surface sheet 11 , a back sheet 12 and a side sheet 14 , which extend in the lateral direction X outside the longitudinal direction Y of the first and second end edges 20 a and 20 b of the absorber 20 . Both end portions 16 ; and both side edge portions 17 extending in the longitudinal direction Y outside the lateral direction X of the first and second side edges 20c and 20d of the absorber 20 . In the center part of the vertical direction Y of the sanitary napkin 10, there exists a flap part 18 which becomes convex toward the outer side of the horizontal direction X, and is formed by a part of the edge part 17 on both sides. In addition, the sheets 11 , 12 , and 14 laminated to each other are joined to each other via the outer peripheral sealing portion 19 existing along the outer peripheral edge of the sanitary napkin 10 .

As shown in FIG. 2 , on the back side of the sanitary napkin 10, a plurality of fixing regions 30 are arranged. The plurality of fixing regions 30 are used for fixing the sanitary napkin 10 to clothing such as underwear, and are formed by applying a plurality of linear adhesives, pressure-sensitive adhesives, etc. extending in the longitudinal direction Y. . The fixing region 30 has a central region 31 extending in the longitudinal direction Y in a region overlapping with the absorber 20 , and a side region 32 located in the flap portion 18 . The fixing region 30 is covered with a separator (not shown) made of a plastic film.

The surface sheet 11 is liquid-permeable, has a skin-facing surface (upper surface) 11a and a non-skin-facing surface (lower surface) 11b on the opposite side, and is formed by a laminated sheet of the woven fabric 40 and the fiber web 50 . In addition, the back sheet 12 may be formed of a liquid-impermeable and moisture-permeable plastic film, a liquid-impermeable nonwoven fabric, a laminated sheet of these, or the like. As the side sheet 14, a conventional non-woven fabric can be used, but in order to effectively prevent lateral leakage of body fluids, a sheet material having hydrophobicity or water repellency is preferably used.

The outer peripheral sealing portion 19 can be joined by adhesive, joining by conventional welding means such as ultrasonic welding, thermal welding, laser welding, high-frequency welding, and joining by embossing processing independently. , or a combination. In addition, the sheets 11 , 12 , and 14 laminated in the thickness direction Z are bonded to each other via an adhesive such as a hot-melt adhesive. As a coating method of a hot-melt adhesive agent, various conventional coating methods, such as a spiral coating, a coater coating, a curtain coater coating, and a spray coating, are mentioned, for example.

As shown in FIGS. 3 and 4 , the absorber 20 includes a liquid-absorbent core material obtained by mixing superabsorbent polymer particles (SAP) with cellulose fibers such as fluff wood pulp and rayon fibers and shaping them into a predetermined shape. 21; and a liquid-permeable core-material covering sheet 22 that covers the entirety of the liquid-absorbent core material 21 in order to improve its shape retention and liquid diffusivity.

The size of the core material covering sheet 22 in the longitudinal direction Y is larger than the size in the longitudinal direction Y of the liquid-absorbent core material, and the both side edge portions 22a and 22b are used to cover the entire liquid-absorbent core material 21, and are not suitable for liquid absorption. The bottom surface side of the center part of the horizontal direction X of the core material 21 exists so that it may overlap with each other. By folding both side edge parts 22a, 22b to each other, in the center part of the horizontal direction X of the absorber 20, an overlapped part is formed in which the side edge parts 22a, 22b extending in the vertical direction Y are stacked on each other. twenty three.

The core material covering sheet 22 has: the first covering part 25 covering the skin-facing surface side of the liquid-absorbent core material 21; and the second covering part 26 covering the non-skin-facing surface side of the liquid-absorbent core material 21. In the present embodiment, the core material covering sheet 22 is formed of one continuous sheet, but the first core material covering sheet forming the first covering portion 25 and the first core material covering sheet which are different from the first core material covering sheet and It consists of the 2nd core material covering sheet which forms the 2nd covering part 26.

FIG. 4 is a partially enlarged view of the surface sheet 11 , and FIG. 5 is an exploded perspective view of the surface sheet 11 . The surface sheet 11 includes: the fabric 40 on the skin-opposite side; and the fiber web 50 on the non-skin-opposite side. The fabric 40 has a lower surface (first surface) 40a facing the fiber web 50, and an upper surface (second surface) 40b located on the opposite side of the lower surface 40a. Fabric 40 and web 50 are integrated by intertwining. Furthermore, depending on the wearing state of the absorbent article, there may be cases where the upper surface 40b of the fabric 40 is located below and the lower surface 40a is located above.

The fabric 40 is made up of constituent threads 41 woven into a mesh. The constituent yarn 41 has a plurality of warp yarns 42 and a plurality of weft yarns 43 intersecting with the warp yarns 42, and a plurality of meshes 45 are formed by the warp yarns 42 and the weft yarns 43 intersecting each other in the thickness direction Z. The constituent yarn 41 of the fabric 40 is a twisted yarn formed by twisting a raw yarn formed of cotton threads (cotton fibers). As the raw yarn material, besides cotton fibers, cellulose fibers such as natural cellulose fibers such as pulp fibers, regenerated cellulose fibers such as rayon, and hemisynthetic cellulose fibers such as acetates can be preferably used. However, as long as the technical effects of the present invention described later can be achieved, materials such as thermoplastic resin fibers such as polyethylene and polypropylene, and mixtures of cellulose fibers and these fibers can be appropriately used. The number of yarns (the sum of warp and weft) constituting the thread 41 is 60 to 100, and as the cotton yarn used as the original yarn, a cotton yarn having a thickness of 10 to 100 can be preferably used.

The fiber web 50 is formed by a conventional manufacturing method such as a spunbonding method using long fibers, a dry method in which short fibers are arranged in a certain direction on a carding machine to form a net shape, and a fiber aggregate at a stage before it is formed into a nonwoven fabric. , that is, the constituent fibers 51 including hydrophilic fibers and hydrophobic fibers are formed. Hydrophobic fibers, except those using polyolefin-based thermoplastic fibers containing polypropylene (PP), polyethylene (PE), polyester-based thermoplastic fibers containing polyethylene terephthalate (PET), etc. In addition to the single fibers, various types of conjugated fibers such as core-sheath conjugated fibers, side-by-side conjugated fibers, and sea-island conjugated fibers can also be used.

Examples of hydrophilic fibers include natural cellulose fibers such as cotton and pulverized pulp, regenerated cellulose fibers such as rayon and fibril rayon, and semi-synthetic cellulose such as acetate, which have been subjected to hydrophilization treatment. Thermoplastic resin fibers, composite fibers, etc. In the present embodiment, the constituent fibers 51 of the fiber web 50 have hydrophobic fibers of 10 to 20 gsm and hydrophilic fibers of 5 to 10 gsm.

As a method of entangling and integrating the fabric 40 and the fiber web 50, for example, a known fluid entanglement method can be used. In the production process of the liquid-permeable sheet by the fluid entanglement method, the continuous lamination constituted by laminating the continuous fiber web as the material of the fiber web 50 on the upper surface of the continuous network structure as the material of the fabric 40 From the upper side, from a plurality of nozzles arranged at intervals in a direction intersecting with the conveying direction of the continuous laminated body, a fluid such as gas or water is sprayed at high pressure, whereby the fibers (including long fibers) of the continuous fiber web can be Fibers and short fibers) and the constituent threads of the continuous network are entangled and integrated.

The continuous lamination system is conveyed by a conveying means consisting of a metal mesh belt. When the fluid is sprayed from the nozzle to the upper surface of the continuous lamination body, on the upper surface side, the fibers of the continuous fiber web and the continuous mesh are formed. The constituent threads of the structure are entangled, and the lower surface side facing the conveying means is also entangled by the fluid that collides with the conveying means and bounces back. Since the surface sheet 11 is a fiber web 50 formed of fiber aggregates entangled with the fabric 40 by the fluid entanglement method, the fiber web 50 has a higher quality than the case where the nonwoven fabric sheets are layered and then fluidly entangled. The constituent fibers 51 are easily entangled with the woven fabric 40, and the laminated state can be maintained more stably. Furthermore, by appropriately changing the structure of the mesh belt of the conveying means according to the fluid entanglement method, the surface sheet 11 having desired sheet properties can be obtained with respect to thickness, mass, absorption speed, sheet strength, and the like.

The topsheet 11 is formed by integrating the fabric 40 on the skin-opposite side and the fiber web 50 on the non-skin-opposite side by entanglement. Therefore, compared with the case where the topsheet 11 is only formed of non-woven fabric, It has higher strength and can give fabrics such a soft texture. Moreover, since the fabric 40 has a mesh structure, the contact area with the skin can be reduced, and a dry touch can be provided.

The menstrual blood excreted in the topsheet 11 spreads along the warp yarns 42 and weft yarns 43 of the woven fabric 40 , and travels toward the lower absorber 20 along the constituent fibers 51 of the fiber web 50 extending downward from the meshes 45 of the woven fabric 40 . In addition, compared with the case where the surface sheet 11 is formed of a liquid-permeable nonwoven fabric, even if the sheet quality is the same, by having a mesh shape formed by the constituent threads 41 having a larger fineness than the constituent fibers 51 of the fiber web 50 The fabric 40 makes the sheet rigidity higher. Thereby, the topsheet 11 can be effectively prevented from curling, floating, and the like from the absorber 20 .

In the case where the surface sheet is formed of only non-woven fabric containing hydrophilic fibers, due to its good absorption rate and liquid diffusivity, even a small amount of menstrual blood excretion will spread rapidly to a wide area and stain the skin, which may cause skin problems, etc. s reason. In the present embodiment, since the surface sheet 11 is formed by a laminated sheet of the fabric 40 and the fiber web 50, menstrual blood is not easily diffused along the constituent lines of the fabric 40, and when the amount of excretion is small, it forms point-like absorption, so it is possible to suppress the When the skin is soiled widely, causing skin problems.

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 4 , and shows the absorber 20 located below the surface sheet 11 by an imaginary line. As shown in FIG. 6 , in the surface sheet 11 , the constituent fibers 51 of the fiber web 50 extend outward in the thickness direction Z from the fabric 40 . Specifically, the fiber web 50 has a downward extending portion 52 extending downward from the lower surface (first surface) 40 a of the fabric 40 , and an upward extending portion extending upward from the upper surface (second surface) 40 b of the fabric 40 . (The part that extends from the second surface) 53.

That is, a portion of the web 50 originates from the fabric 40 on the same plane as or above the upper surface 40b. In the case where the surface sheet 11 is formed by the fluid entanglement method, the lower extending portion 52 of the fiber web 50 is a continuous fiber web from which the fluid is ejected at high pressure, and the upper extending portion 53 is a portion of the constituent fibers of the continuous fiber web penetrating the lower portion. The portion of the continuous mesh body of the material of the fabric 40 extending toward the mesh belt side as the conveying means.

The bodily fluids excreted on the surface sheet 11 are absorbed and diffused by the hydrophilic fibers contained in the upper extending portion 53 of the fiber web 50, and are diffused in the longitudinal direction Y and the lateral direction X by the warp yarns 42 and weft yarns 43 of the fabric 40, and rapidly. Move to the absorber 20 . At this time, since a part of the fiber web 50 is substantially the same as the upper surface 40b of the fabric 40 or located above it, it can be close to the skin to increase the absorption area of menstrual blood, and more menstrual blood can be absorbed. In addition, since a part of the fiber web 50 containing the hydrophobic fibers is positioned above the upper surface 40b of the fabric 40, it is possible to suppress a so-called moisture regain phenomenon in which the body fluid absorbed and held by the fabric 40 and the absorber 20 flows back due to body pressure or the like ( Rewet back) generated.

Since the fabric 40 is composed of a plurality of warp yarns 42 that extend continuously and a plurality of weft yarns 43 that extend continuously in the thickness direction Z in a manner of crossing the warp yarns, it is difficult to cause direct contact with the skin and wear during wear. In use, the body pressure is loaded, or the strength is reduced due to contact with menstrual blood, and it is not easy to produce hairballs and relaxation.

Since the fabric 40 is located closer to the skin than the fiber web 50 , and the constituent threads 41 having a larger fineness than the constituent fibers 51 of the fiber web 50 and high rigidity, can scrape the menstrual blood adhering to the skin. In particular, when menstrual blood comes into contact with the air and hardens over time, it will adhere to the skin and stick to the skin. Therefore, in the past, only the surface sheet made of soft fiber nonwoven fabric could not be scraped off. The fabric 40 , which is not easily reduced under body pressure and in contact with menstrual blood, directly or indirectly contacts the skin, so that the menstrual blood that is tightly adhered to the skin can also be wiped off by using a plurality of meshes 45 . In addition, when the constituent yarns 41 of the woven fabric 40 are formed of twisted yarns, since the entire outer peripheral surface is convex and concave, the scraping property can be further improved.

As for the thickness dimension D2 of the fabric 40, the thickness dimension D3 of the upper extending portion 53 extending upward from the upper surface 40b of the fabric 40 in the fiber web 50 is preferably 1.1 to 4.0 times. When the thickness dimension D3 has this dimension relatively, the scraping property and the suppression of the moisture regain phenomenon can be simultaneously achieved. That is, when the thickness dimension D3 is less than 1.1 times the thickness dimension D2, although the fabric 40 becomes close to the skin, the scraping property becomes high, but only the part of the fiber web 50 is thin, and there is a possibility that the fabric 40 cannot be used for the purpose of the skin. The moisture regain phenomenon is effectively suppressed by the fiber web 50 containing hydrophobic fibers. In addition, when the thickness dimension D3 exceeds 4.0 times the thickness dimension D2, the moisture regain phenomenon can be suppressed by extending the portion 53 above the thick fiber web 50, and bodily fluids can be absorbed along the constituent fibers 51. 40 is located far away from the skin, so it becomes difficult to scrape the menstrual blood adhering to the skin.

<Measurement method of thickness dimension> Here, the thickness dimension D2 of the woven fabric 40 is measured in the state of the material using a gauge having a diameter of 50 mm [PEACOCK Dial thickness gauge J-B manufactured by Ozaki Seisakusho Co., Ltd.]. In addition, the thickness dimension D1 of the top sheet 11 is the thickness of the appearance. As shown in FIG. 6 , the top sheet 11 is ideally cut along the machine direction of the fiber web 50, and is cut using a digital microscope VHX-1000 manufactured by Keenes Corporation. A magnified photograph of the surface is photographed, and the maximum thickness dimension of the surface sheet 11 is measured based on the magnified photograph. The same measurement is performed at 5 randomly designated locations to obtain an average value, and the average value is used as the thickness dimension of the surface sheet 11. D1. In addition, the value obtained by subtracting the thickness dimension D2 of the fabric 40 and the thickness dimension of the lower extending portion 52 from the thickness dimension D1 of the surface sheet 11 is used as the thickness dimension of the upper extending portion 53 of the fiber web 50 (from the upper surface 40b of the fabric 40 ). The separation dimension to the vertex 53a of the upper extension 53) D3. In addition, the measurement operation was performed in a measurement room under a standard environment (temperature 20±5° C., relative humidity 65% or less).

The upper extending portion 53 of the fiber web 50 has a plurality of low bulkiness portions 54 having a smaller thickness dimension D3 and a plurality of high bulkiness portions 55 having a larger thickness dimension D3. Since the lower extending portion 52 of the fiber web 50 has a concave-convex shape, it can effectively scrape the menstrual blood adhering to the skin together with the fabric 40 located below.

In addition, in the case where the surface sheet 11 is formed by the fluid entanglement method, the portion of the fiber web 50 that is directly collided with the fluid ejected from the nozzle in the lower extending portion 52 directly collided with the fluid ejected from the high-pressure jet is compared with other portions. , its bulkiness is low. The low-bulkiness portion 56 includes a portion where the fluid directly collides, and in this case, the fiber density of the low-bulkiness portion 56 becomes higher than that of the high-bulkiness portion 57 . Therefore, the bodily fluid that travels from the fabric 40 toward the downward downward extending portion 52 can travel to the lower absorbent body more rapidly in the low bulkiness portion 56 having higher fiber density than in the high bulkiness portion 57 .

The fiber web 50 is integrated with the woven fabric 40 by entanglement without an adhesive or the like, and thus has better flexibility than the case where the fiber web 50 is joined to each other through an adhesive or the like. As an aspect in which the constituent fibers 51 of the fiber web 50 are entangled with the fabric 40, in addition to being entangled with or entangled with the warp and weft yarns of the fabric 40, a part of the constituent fibers 51 also has a part of the constituent fibers 51. It is entangled so as to enter between the base yarns of the warp yarns 42 and the weft yarns 43 formed of twisted yarns. In this way, the fiber web 50 can be stably integrated into the fabric 40 by entangling the constituent fibers 51 on the outer and inner surfaces of the warp yarns 42 and the weft yarns 43 .

The constituent fibers 51 of the fiber web 50 have a fineness of 0.8 to 6.0 dtex, ideally 1.0 to 4.4 dtex, more ideally 1.3 to 3.3 dtex; the fiber length is 25 to 64 mm, ideally 32 to 58 mm, and more ideally 38 to 51 mm The fineness of the constituent yarn 41 formed by twisted yarn is 10-100 cotton yarn count, ideally 20-60 cotton yarn count, more preferably 30-45 cotton yarn count. Since the constituent fibers 51 of the fiber web 50 are short fibers, a plurality of fiber ends exist in the fiber web 50, and the fiber ends enter between the twisting gaps of the original yarn with a larger fineness, or are wound By being tightly wound around the constituent wire 41 , the fiber web 50 can be stably wound around the fabric 40 .

Again, as shown in FIG. 4, the fiber length of the short fibers of the fiber web 50 is formed to be at least one of the separation dimension R1 of the warp yarns 42 adjacent to each other and parallel to each other, and the separation dimension R2 of the weft yarns 43 adjacent to each other and parallel to each other. The separation size is larger. In this case, the short fibers do not fall off the meshes 45 of the fabric 40, and the short fibers extend across the meshes 45, thereby improving the sheet strength and liquid diffusivity of the surface sheet 11 as a whole.

The content of hydrophilic fibers in the fiber web 50 is less than 50% by mass, preferably 10 to 49% by mass, and the content of hydrophobic fibers is more than 50% by mass, preferably 51 to 90% by mass, in the fiber web 50 , the proportion of hydrophobic fibers is higher than that of hydrophilic fibers. Since the proportion of the hydrophobic fibers is high, the diffusivity can be suppressed, and the moisture regain phenomenon can be suppressed.

Moreover, when the content rate of the hydrophilic fiber is less than 10 mass %, the ratio of the hydrophobic fiber relatively increases, and although the moisture regain phenomenon can be suppressed, the absorbability of menstrual blood from the skin is reduced. In addition, when the content rate of the hydrophilic fiber is 50 mass % or more, although a large amount of menstrual blood is absorbed more quickly, the moisture regain phenomenon tends to occur. The surface sheet 11 can achieve good liquid absorption, liquid diffusivity, and suppression of moisture regain by including hydrophilic fibers and hydrophobic fibers in a balanced manner.

Fig. 7 is an enlarged view of a cross-sectional shape of an example of a hydrophilic fiber having a different cross-sectional shape. The hydrophilic fibers 60 are thermoplastic resin fibers subjected to hydrophilization treatment, such as hydrophilic PET fibers, and have a plurality of grooves 61 extending toward the extending direction. Since the hydrophilic fiber 60 has a plurality of grooves 61 extending in the extending direction, the surface area in contact with the menstrual blood becomes larger than when the outer peripheral surface is flat, and the inhalation of the menstrual blood can be improved.

In an example of another example of the present embodiment, as the material of the raw yarn of the fabric 40, unbleached pulp fibers that have not been subjected to lignin removal treatment at all can be used. In this case, since the unbleached pulp fiber containing a large amount of lignin has a light brown color derived from the natural material itself, the entire surface sheet 11 has a natural color tone of light brown. By having the light brown color of the surface sheet 11, it is possible to give the wearer or the like an impression of a skin-friendly product using a natural material with a high degree of natural orientation. In addition, compared with the case of using a white sheet that has been bleached, the redness of the menstrual blood absorbed by the absorber 20 can be suppressed, so that the juveniles who have just started menstruating can reduce the effect of menstruation due to the direct recognition of the menstrual blood. unease. Furthermore, since the lignin component has an excellent antibacterial effect, the sanitary napkin 10 can be worn and discarded more hygienically.

In addition, at least one of the first and second covering portions 25 and 26 of the core covering sheet 22 covering the liquid-absorbent core 21 may contain unbleached pulp fibers. In this case, together with the surface sheet 11 containing the unbleached pulp fiber, a skin-friendly impression with a natural color tone can be given, and the concealment of menstrual blood and antibacterial properties can be contributed.

In this specification, as the liquid-permeable sheet for the absorbent article 10 of the first invention, the embodiment about the topsheet 11 arranged on the skin-opposing surface side of the absorber 20 has been described, but it can also be used as an absorbent The sheet of the article 10 is used, for example, as an intermediate sheet located on the inner surface side of the surface sheet, a core covering sheet, and the like. In addition, the absorbent article 10 is not limited to sanitary napkins, but can also include, for example, disposable diapers for adults and children, and urine absorbing pads, and can also be used as a liquid-permeable sheet through which urine and soft stools can pass.

The disclosure of the first invention described above can be organized into at least the following matters. An absorbent article comprising: a fabric having a first surface and a second surface facing each other in a thickness direction; and a fiber web integrated with the first surface of the fabric by entanglement In the fiber web, the constituting threads of the woven fabric are formed of cellulose fibers, and the constituting fibers of the fiber web are substantially on the same surface as the second surface of the fabric, or extend outward in the thickness direction.

The liquid-permeable sheet for absorbent articles of the first invention described above includes the following embodiments. (1) As for the thickness dimension of the woven fabric, the thickness dimension of the portion of the fiber web extending from the second surface of the woven fabric is 1.1 to 4.0 times. (2) A portion of the constituent fibers of the fiber web is the constituent thread wound around the woven fabric, and extends toward the second surface side through a plurality of meshes of the woven fabric. (3) The constituent fibers of the fiber web include hydrophilic fibers and hydrophobic fibers, and the content of the hydrophobic fibers is higher than the content of the hydrophilic fibers. (4) The above-mentioned hydrophilic fibers are shaped in cross-section and have a plurality of grooves extending in the extending direction. (5) The above-mentioned fiber web and the above-mentioned fabric are treated by fluid entanglement, and the entanglement is integrated. (6) The fiber web is composed of short fibers, the fiber length of the short fibers is 25 to 64 mm, and the fineness is 0.8 to 6.0 dtex. The fineness of the aforementioned twisted yarn is 10 to 100 cotton yarn counts. (7) The said absorbent article is further provided with an absorber, and is arrange|positioned at the skin opposing surface side of the said absorber. (8) The fiber length of the short fibers is larger than at least one of the separation dimension of the adjacent and parallel warp yarns and the separation dimension of the adjacent and parallel weft yarns.

(2nd invention) The following embodiment includes not only the structure indispensable to the invention but also the optional and ideal structure about the absorbent article shown in the drawing. Hereinafter, the embodiment of the sanitary napkin 210 which is an example of the absorbent article of the present invention will be described with reference to the drawings. The sanitary napkin 210 has a vertical direction Y, a horizontal direction X, and a thickness direction Z.

As shown in FIG. 8 to FIG. 10 , the sanitary napkin 210 has a vertical centerline P that bisects the dimension in the width direction and a horizontal centerline Q that bisects the dimension of the longitudinal dimension, and includes: a skin-facing surface The non-skin facing surface (outer surface) side on the (inner surface) side and its opposite side; the convexly curved first and second end edges 210a and 210b; in the central part where the horizontal center line Q exists, the convexly curved first and second end edges 210a and 210b are formed. 1 and 2 side edges 210c, 210d; the liquid-permeable surface sheet 211 on the skin-opposite side; the liquid-impermeable back sheet 212 on the non-skin-opposite side; and between these two sheets 211, 212 The liquid absorbent absorber 220. The surface sheet 211 and the absorber 220 are bonded to each other by conventional bonding means such as hot-melt adhesive to form the liquid-absorbing layer 213 .

In addition, although not shown, in order to improve the softness of the sanitary napkin 210, an intermediate sheet made of nonwoven fabric with high bulkiness may be arranged between the surface sheet (liquid-permeable sheet) 211 and the absorber 220. Moreover, between the absorber 220 and the back sheet 212, in order to suppress leakage of bodily fluids, a leak-proof sheet preferably made of a non-woven fabric or a plastic film having air permeability and liquid impermeability may be arranged.

The absorber 220 includes: a first end edge 220a facing the first end edge 210a; a second end edge 220b facing the second end edge 210b; and between the first and second end edges 220a, 220b, The first and second side edges 220c and 220d extending in the vertical direction Y. The front and back sheets 211 and 212 extend outward from the outer periphery of the absorber 220, and on the skin-opposing surface side of the top sheet 211, a pair extending in the vertical direction Y is arranged so as to face each other in the lateral direction X. Side flaps 214 . The pair of side sheets 214 are joined to the surface sheet 211 via a conventional adhesive means or a side joining portion (not shown) formed by a welding means. Although not shown, in the side sheet 214, in order to form a leak-proof wall standing up toward the body side in the wearing state, the elastic material extending in the longitudinal direction Y may be arranged so as to be shrinkable in the extended state. In addition, the side joint portion for fixing the side sheet 214 may be a sealing line extending in the longitudinal direction Y having design elements such as floral patterns and geometric patterns.

The sanitary napkin 210 has a surface sheet 211 , a back sheet 212 and a side sheet 214 , which extend in the lateral direction X outside the longitudinal direction Y of the first and second end edges 220 a and 220 b of the absorber 220 . Both end portions 216 ; and both side edge portions 217 extending in the longitudinal direction Y outside the lateral direction X of the first and second side edges 220 c and 220 d of the absorber 220 . In the center part of the vertical direction Y of the sanitary napkin 210, there exists a flap part 218 which becomes convex toward the outer side of the horizontal direction X, and is formed by a part of the edge part 217 of both sides. In addition, the sheets 211 , 212 , and 214 laminated to each other are joined to each other via the outer peripheral sealing portion 219 existing along the outer peripheral edge of the sanitary napkin 210 .

As shown in FIG. 9, on the back side of the sanitary napkin 210, a plurality of fixing regions 230 are arranged. The plurality of fixing regions 230 are used for fixing the sanitary napkin 210 to clothing such as underwear, and are formed by applying a plurality of linear adhesives, pressure-sensitive adhesives, etc. that extend in the longitudinal direction Y. . The fixing region 230 has a central region 231 extending in the longitudinal direction Y in a region overlapping with the absorber 220 , and a side region 232 located in the flap portion 218 . The fixing region 230 is covered with a separator (not shown) made of a plastic film.

The surface sheet 211 is liquid-permeable, has a skin-facing surface 211a and a non-skin-facing surface 211b on the opposite side thereof, and is formed of a laminated sheet of the fabric 240 and the fiber web 250 . In addition, the back sheet 212 may be formed of a liquid-impermeable and moisture-permeable plastic film, a liquid-impermeable nonwoven fabric, a laminated sheet of these, or the like. As the side sheet 214, a conventional non-woven fabric can be used, but in order to effectively prevent lateral leakage of bodily fluids, a sheet material with hydrophobicity or water repellency is preferably used.

The outer peripheral sealing portion 219 can be joined by adhesive, joining by conventional welding means such as ultrasonic welding, thermal welding, laser welding, high-frequency welding, and welding by embossing. , or a combination. In addition, the sheets 211 , 212 , and 214 laminated in the thickness direction Z are bonded to each other via an adhesive such as a hot melt adhesive. As a coating method of a hot-melt adhesive agent, various conventional coating methods, such as a spiral coating, a coater coating, a curtain coater coating, and a spray coating, are mentioned, for example.

As shown in FIGS. 10 and 11 , the absorber 220 includes a liquid-absorbent core material obtained by mixing superabsorbent polymer particles (SAP) with cellulose fibers such as fluff wood pulp and rayon fibers and shaping them into a predetermined shape. 221; and a liquid-permeable core-material covering sheet 222 that covers the entirety of the liquid-absorbent core material 221 in order to improve its shape retention and liquid diffusivity.

The size of the core material covering sheet 222 in the longitudinal direction Y is larger than the size in the longitudinal direction Y of the liquid-absorbent core material, and the both side edge portions 222a and 222b are used to cover the entire liquid-absorbent core material 221, and are not suitable for liquid absorption. The bottom surface side of the center part of the horizontal direction X of the core material 221 exists so that it may overlap with each other. By folding both side edge parts 222a and 222b to each other, in the center part of the horizontal direction X of the absorber 220, an overlapping part is formed in which the side edge parts 222a and 222b extending in the vertical direction Y are stacked on each other. 223.

The core material covering sheet 222 has a first covering portion 225 covering the skin-opposing surface side of the liquid-absorbent core material 221 , and a second covering portion 226 covering the non-skin-facing surface side of the liquid-absorbent core material 221 . In the present embodiment, the core material covering sheet 222 is formed of one continuous sheet, but the first core material covering sheet forming the first covering portion 225 and the first core material covering sheet which is different from the first core material covering sheet may be formed. It consists of the 2nd core material covering sheet which forms the 2nd covering part 226.

FIG. 11 is a partially enlarged view of the surface sheet 211 , and FIG. 12 is an exploded perspective view of the surface sheet 211 . The surface sheet 211 includes: the fabric 240 on the skin-opposite side; and the fiber web 250 on the non-skin-opposite side. The fabric 240 has a lower surface (first surface) 240a facing the fiber web 250, and an upper surface (second surface) 240b located on the opposite side of the lower surface 240a. The fabric 240 and the web 250 are integrated by intertwining. Furthermore, depending on the wearing state of the absorbent article, there may be cases where the upper surface 240b of the fabric 240 is located below and the lower surface 240a is located above.

The fabric 240 is composed of the constituent threads 241 woven into a mesh. The constituent thread 241 has a plurality of warp yarns 242 and a plurality of weft yarns 243 intersecting with the warp yarns 242, and a plurality of meshes 245 are formed by the warp yarns 242 and the weft yarns 243 intersecting each other in the thickness direction Z. The constituent yarn 241 of the woven fabric 240 is a twisted yarn formed by twisting a raw yarn formed of cotton threads (cotton fibers). As the raw yarn material, besides cotton fibers, cellulose fibers such as natural cellulose fibers such as pulp fibers, regenerated cellulose fibers such as rayon, and hemisynthetic cellulose fibers such as acetates can be preferably used. However, as long as the technical effects of the present invention described later can be achieved, materials such as thermoplastic resin fibers such as polyethylene and polypropylene, and mixtures of cellulose fibers and these fibers can be appropriately used. The number of yarns (the sum of warp and weft) constituting the thread 241 is 60 to 100, and the cotton yarn used as the base yarn is preferably a cotton yarn with a thickness of 10 to 100.

The fiber web 250 is formed by a conventional manufacturing method such as a spunbonding method using long fibers, a dry method of arranging short fibers in a certain direction on a carding machine to form a net shape, and the fiber aggregate at the stage before being formed into a nonwoven fabric. , that is, the constituent fibers 251 including hydrophilic fibers and hydrophobic fibers are formed. Hydrophobic fibers, except those using polyolefin-based thermoplastic fibers containing polypropylene (PP), polyethylene (PE), polyester-based thermoplastic fibers containing polyethylene terephthalate (PET), etc. In addition to the single fibers, various types of conjugated fibers such as core-sheath conjugated fibers, side-by-side conjugated fibers, and sea-island conjugated fibers can also be used.

Examples of hydrophilic fibers include natural cellulose fibers such as cotton and pulverized pulp, regenerated cellulose fibers such as rayon and fibril rayon, and semi-synthetic cellulose such as acetate, which have been subjected to hydrophilization treatment. Thermoplastic resin fibers, composite fibers, etc. In this embodiment, the constituent fibers 251 of the fiber web 250 have hydrophobic fibers of 10 to 20 gsm and hydrophilic fibers of 5 to 10 gsm.

As a method of entangling and integrating the fabric 240 and the fiber web 250, for example, a known fluid entanglement treatment method can be used. In the production process of the liquid-permeable sheet by the fluid entanglement treatment method, a continuous layer composed of the continuous fiber web as the material of the fiber web 250 is laminated on the upper surface of the continuous network structure as the material of the fabric 240 From the upper side, a plurality of nozzles arranged at intervals in the direction intersecting with the conveying direction of the continuous laminated body inject fluids such as gas and water at high pressure, whereby the fibers (including the fibers of the continuous fiber web) can be formed. Long fibers and short fibers) and the constituent threads of the continuous network are entangled and integrated.

The continuous lamination system is conveyed by a conveying means consisting of a metal mesh belt. When the fluid is sprayed from the nozzle to the upper surface of the continuous lamination body, on the upper surface side, the fibers of the continuous fiber web and the continuous mesh are formed. The constituent threads of the structure are entangled, and the lower surface side facing the conveying means is also entangled by the fluid that collides with the conveying means and bounces back. Since the surface sheet 211 entangles the fiber web 250 formed of fiber aggregates with the fabric 240 by the fluid entanglement method, the fiber web 250 has a higher quality than the case where the non-woven fabric sheets are layered and then fluidly entangled. The constituent fibers 251 are easily entangled with the woven fabric 240, and the laminated state can be maintained more stably. Furthermore, by appropriately changing the structure of the mesh belt of the conveying means according to the fluid entanglement method, the surface sheet 211 having desired sheet properties can be obtained with respect to thickness, mass, absorption speed, sheet strength, and the like.

The topsheet 211 is formed by integrating the fabric 240 on the skin-opposite side and the fiber web 250 on the non-skin-opposite side by entanglement. Therefore, compared with the case where the topsheet 211 is only made of non-woven fabric, It has higher strength and can give fabrics such a soft texture. Moreover, since the fabric 240 has a mesh structure, the contact area with the skin can be reduced, and a dry touch can be provided.

The menstrual blood excreted in the surface sheet 211 spreads along the warp yarns 242 and the weft yarns 243 of the fabric 240, and travels toward the lower absorber 220 along the constituent fibers 251 of the fiber web 250 extending downward from the meshes 245 of the fabric 240. In addition, compared with the case where the surface sheet 211 is formed of a liquid-permeable nonwoven fabric, even if the sheet quality is the same, by having the constituent fibers 251 of the fiber web 250, the mesh shape formed by the constituent threads 241 having a larger fineness The fabric 240 makes the sheet rigidity higher. Thereby, the topsheet 211 can be effectively prevented from curling, floating, and the like from the absorber 220 .

Generally, the surface sheet used for sanitary napkins is thin and contains a large amount of hydrophilic fibers. Therefore, the fibers that swell after absorbing menstrual blood become sticky easily. Therefore, when the sanitary napkin is housed in an individual package in a folded state, a crease may be generated. When a creased sanitary napkin is attached to underwear or the like, a gap is formed between a part of the sanitary napkin and the body, which may cause lateral leakage of menstrual blood and reduce wearing comfort.

Since the surface sheet 211 includes hydrophilic fibers and hydrophobic fibers, and the ratio of the hydrophobic fibers is higher than that of the hydrophilic fibers, the formation of creases caused by the fibers sticking to each other can be suppressed. In addition, the surface sheet 211 is located on the skin-opposing surface (inner surface) side by a fabric 240 having higher rigidity than a sheet material such as non-woven fabric, so that creases are less likely to occur. Therefore, when the sanitary napkin is taken out from the individual package housed in the folded state, the creases along the bending line, which can cause lateral leakage of menstrual blood, are less likely to occur.

In the case where the surface sheet is formed of only non-woven fabric containing hydrophilic fibers, due to its good absorption rate and liquid diffusivity, even a small amount of menstrual blood excretion will spread rapidly to a wide area and stain the skin, which may cause skin problems, etc. s reason. In the present embodiment, the surface sheet 211 is formed by a laminated sheet of the fabric 240 and the fiber web 250, so that the menstrual blood is not easily diffused along the constituent lines of the fabric 240, and when the excretion amount is small, it forms point-like absorption, so it can be suppressed When the skin is soiled widely, causing skin problems.

FIG. 13 is a cross-sectional view taken along the line XIII-XIII in FIG. 11 , and shows the absorber 220 under the surface sheet 211 by an imaginary line. As shown in FIG. 13 , in the surface sheet 211 , the constituent fibers 251 of the fiber web 250 extend outward in the thickness direction Z from the fabric 240 . Specifically, the fiber web 250 has a downward extending portion 252 extending downward from the lower surface (first surface) 240 a of the fabric 240 , and an upward extending portion extending upward from the upper surface (second surface) 240 b of the fabric 240 (The part that extends from the second side) 253.

That is, a portion of the web 250 is positioned from the fabric 240 on the same plane as the upper surface 240b or above it. In the case where the surface sheet 211 is formed by the fluid entanglement method, the lower extending portion 252 of the fiber web 250 is a continuous fiber web in which the fluid is ejected at high pressure, and the upper extending portion 253 is a portion of the constituent fibers of the continuous fiber web that penetrates the lower portion of the fiber web. The portion of the continuous mesh body of the material of the fabric 240 that extends toward the mesh belt side as the conveying means.

The bodily fluids discharged on the surface sheet 211 are absorbed and diffused by the hydrophilic fibers contained in the upper extending portion 253 of the fiber web 250, and are diffused in the longitudinal direction Y and the transverse direction X by the warp yarns 242 and the weft yarns 243 of the fabric 240, rapidly. Move to the absorber 220 . At this time, since a part of the fiber web 250 is substantially the same as the upper surface 240b of the fabric 240 or located above it, it can be close to the skin to increase the absorption area of menstrual blood, and more menstrual blood can be absorbed. In addition, since a part of the fiber web 250 containing the hydrophobic fibers is positioned above the upper surface 240b of the fabric 240, the so-called rewetting phenomenon (Rewet) of the bodily fluid absorbed and held by the fabric 240 and the absorber 220 due to body pressure and the like can be suppressed. back) is generated.

Since the fabric 240 is composed of a plurality of warp yarns 242 that extend continuously and a plurality of weft yarns 243 that extend continuously in the thickness direction Z in a manner of crossing the warp yarns, it is difficult to cause direct contact with the skin and wear during wear. In use, the body pressure is loaded, or the strength is reduced due to contact with menstrual blood, and it is not easy to produce hairballs and relaxation.

The fabric 240 is located closer to the skin side than the fiber web 250 , and the constituent threads 241 having a larger fineness than the constituent fibers 251 of the fiber web 250 and high rigidity can scrape the menstrual blood adhering to the skin. In particular, when menstrual blood comes into contact with the air and hardens over time, it will adhere to the skin and stick to the skin. Therefore, in the past, only the surface sheet made of soft fiber nonwoven fabric could not be scraped off. The fabric 240 , which is not easily reduced under body pressure and in contact with menstrual blood, directly or indirectly contacts the skin, so that the menstrual blood that is tightly adhered to the skin can also be wiped off by using a plurality of meshes 245 . In addition, when the constituent yarns 241 of the woven fabric 240 are formed of twisted yarns, since the entire outer peripheral surface is convex and concave, the scraping property can be further improved.

For the thickness dimension D2 of the fabric 240, the thickness dimension D3 of the upper extending portion 253 extending upward from the upper surface 240b of the fabric 240 in the fiber web 250 is preferably 1.1 to 4.0 times. When the thickness dimension D3 has this dimension relatively, the scraping property and the suppression of the moisture regain phenomenon can be simultaneously achieved. That is, when the thickness dimension D3 is less than 1.1 times the thickness dimension D2, although the fabric 240 is closer to the skin, the scraping property is improved, but only the part of the fiber web 250 is thin, and there is a possibility that the The moisture regain phenomenon is effectively suppressed by the fiber web 250 containing hydrophobic fibers. In addition, when the thickness dimension D3 exceeds 4.0 times the thickness dimension D2, the moisture regain phenomenon can be suppressed by extending the portion 253 above the thicker fiber web 250, and the body fluid can be absorbed along the constituent fibers 251. 240 is located away from the skin, so it becomes difficult to scrape the menstrual blood adhering to the skin.

<Measurement method of thickness dimension> Here, the thickness dimension D2 of the woven fabric 240 is measured in the state of the material using a gauge having a diameter of 50 mm [PEACOCK Dial thickness gauge J-B manufactured by Ozaki Seisakusho Co., Ltd.]. In addition, the thickness dimension D1 of the surface sheet 211 is the thickness of the appearance. As shown in FIG. 13 , the surface sheet 211 is ideally cut along the machine direction of the fiber web 250, and is cut using a digital microscope VHX-1000 manufactured by Keenes Corporation. An enlarged photo of the surface is taken, and the maximum thickness dimension of the surface sheet 211 is measured based on the enlarged photo, and the same measurement is performed at 5 randomly designated locations to obtain an average value, and the average value is used as the thickness dimension of the surface sheet 211. D1. In addition, the thickness dimension D1 of the surface sheet 211 minus the thickness dimension D2 of the fabric 240 and the thickness dimension of the lower extension part 252 is taken as the thickness dimension of the upper extension part 253 of the fiber web 250 (from the upper surface 240b of the fabric 240 The separation dimension to the vertex 253a of the upper extension 253) D3. In addition, the measurement operation was performed in a measurement room under a standard environment (temperature 20±5° C., relative humidity 65% or less).

The upper extending portion 253 of the fiber web 250 has: a plurality of low loft portions 254 having a smaller thickness dimension D3; and a plurality of high loft portions 255 having a larger thickness dimension D3. Since the lower extending portion 252 of the fiber web 250 has a concave and convex shape, it can effectively scrape the menstrual blood adhering to the skin together with the fabric 240 located below.

In addition, in the case where the surface sheet 211 is formed by the fluid entanglement method, the portion of the fiber web 250 that is directly collided with the fluid ejected from the nozzle in the lower extending portion 252 directly collided with the fluid ejected from the high-pressure jet is compared with other portions. , its bulkiness is low. The low loft portion 256 includes a portion where the fluid directly collides, and in this case, the fiber density of the low loft portion 256 becomes higher than that of the high loft portion 257 . Therefore, the bodily fluid that travels from the fabric 240 toward the downward downward extending portion 252 can travel to the lower absorbent body more rapidly in the low bulkiness portion 256 having higher fiber density than in the high bulkiness portion 257 .

The fiber web 250 is integrated with the woven fabric 240 by entanglement without an adhesive or the like, and thus has better flexibility than the case where the fiber web 250 is joined to each other via an adhesive or the like. As an aspect in which the constituent fibers 251 of the fiber web 250 are entangled with the fabric 240, in addition to a part of the constituent fibers 251 being entangled with or entangled with the warp and weft yarns of the fabric 240, there is also a part of the constituent fibers 251. The warp yarns 242 and the weft yarns 243 formed by twisted yarns are intertwined so as to be intertwined. In this way, the fiber web 250 can be stably integrated into the fabric 240 by entangling the constituent fibers 251 on the outer and inner surfaces of the warp yarns 242 and the weft yarns 243 .

The fiber 251 constituting the fiber web 250 has a fineness of 0.8 to 6.0 dtex, ideally 1.0 to 4.4 dtex, and more ideally 1.3 to 3.3 dtex; the fiber length is 25 to 64 mm, ideally 32 to 58 mm, and more ideally 38 to 51 mm. The fineness of the constituent yarn 241 formed by twisted yarn is 10-100 cotton yarn count, ideally 20-60 cotton yarn count, more preferably 30-45 cotton yarn count. Since the constituent fibers 251 of the fiber web 250 are short fibers, a plurality of fiber ends exist in the fiber web 250, and the fiber ends enter between the twisting gaps of the original yarn with a larger fineness, or are wound The fiber web 250 can be stably wound around the fabric 240 by being tightly wound around the constituent wire 241 .

Again, as shown in FIG. 11 , the fiber length of the short fibers of the fiber web 250 is formed to be at least one of the separation dimension R1 of the warp yarns 242 adjacent to each other and parallel to each other, and the separation dimension R2 of the weft yarns 243 adjacent to each other and parallel to each other. The separation size is larger. In this case, the short fibers do not fall off from the meshes 245 of the fabric 240, and the short fibers extend across the meshes 245, so that the sheet strength and liquid diffusivity of the entire surface sheet 211 can be improved.

The content of hydrophilic fibers in the fiber web 250 is less than 50% by mass, preferably 10 to 49% by mass, and the content of hydrophobic fibers is more than 50% by mass, preferably 51 to 90% by mass. , the proportion of hydrophobic fibers is higher than that of hydrophilic fibers. Since the proportion of the hydrophobic fibers is high, the diffusivity can be suppressed, and the moisture regain phenomenon can be suppressed.

Moreover, when the content rate of the hydrophilic fiber is less than 10 mass %, the ratio of the hydrophobic fiber relatively increases, and although the moisture regain phenomenon can be suppressed, the absorbability of menstrual blood from the skin is reduced. In addition, when the content rate of the hydrophilic fiber is 50 mass % or more, although a large amount of menstrual blood is absorbed more quickly, the moisture regain phenomenon tends to occur. The surface sheet 211 can achieve good liquid absorption, liquid diffusivity, and suppression of moisture regain by containing hydrophilic fibers and hydrophobic fibers in a balanced manner.

<Distortion Evaluation> First, a liquid-permeable sheet having a thickness of 0.57 mm and a mass of 47 g/m ² was prepared as a sample A corresponding to the Example, which is the material of the surface sheet 211 , and was cut into a length dimension of 100 mm×width dimension. 50mm; and as a sample B corresponding to the comparative example, that is, a cotton sheet (cotton 100%) with a thickness of 0.33mm and a mass of 31 g/m ² was cut into a length dimension of 100mm×width dimension of 15mm. Next, each sample was rubbed under the predetermined measurement conditions (wear resistance 100 times, load 50g) with the Japan Academic Promotion-type rubbing fastness tester, and the state of friction between the surface sheet and the body surface during wearing was reproduced. .

Next, using a torque tester (EX-0762) manufactured by IMADA, under the following measurement conditions, the torque values of each of the samples A and B were measured. Rotation speed: 50rpm Distance between detections: 25mm Rotation angle (measurement angle): 90° (60°) The torque value in the vertical direction Y and the torque value in the lateral direction of each of the samples A and B were obtained and averaged, and the average value was used as the torque value of each sample. In addition, each sample A, B prepared both the state which applied surface rubbing by the rubbing fastness tester, and the state which did not apply surface rubbing, and was measured.

The measurement results show that the torque value of the sample A in the example without surface friction is 7.1, and the torque value in the state with surface friction is 6.8, which corresponds to the state of the sample B in the comparative example without surface friction. The torque value is 3.9, and the torque value in the state where surface friction is applied is 2.2. The surface sheet 211 of the embodiment, depending on whether or not surface friction is applied, does not produce a large change in the torque value, and does not distort during friction with the body during use. In addition, the top sheet 211 has higher sheet rigidity than the cotton sheet of the comparative example, and is less likely to be twisted. The reason why the torque value of the cotton sheet of the comparative example is 55% or less than that of the surface sheet 211 of the example is that in the case of the cotton sheet, when the surface friction is applied, the entanglement of the cotton fibers is unraveled and Caused by the reduction of sheet strength.

＜Torsion evaluation＞ For the measurement of the twist evaluation, the sample C of the sanitary napkin of the Example and the sample D of the sanitary napkin of the comparative example were prepared. Sample C and Sample D have the same structure except for the surface sheet structure. Liquid permeable sheet of sample B. First, a doll imitating the lower body of the human body was prepared, and the sanitary napkins of the samples C and D were worn on the doll. Next, during imaginary walking, 2 g of artificial menstrual blood was discharged from the opening corresponding to the vaginal opening of the doll and dripped onto the surface of the sanitary napkin after moving the thighs of the doll back and forth continuously for 5 minutes. Then, assuming sitting down, the doll's thighs are exchanged to the left and right and the legs are raised. This behavior was performed 5 times as 1 set (5 sets), and the sample was removed from the doll. About the samples C and D in the state removed from the doll, the narrowest width dimension (mm) of the absorber in contact with the narrowest part in the vicinity of the crotch was measured with a measuring tool. This measurement was performed three times, and the average value was used as the narrowest width dimension of the absorber of each sample.

In the measured structure, the narrowest width dimension of the absorber of the sample C using the surface sheet 211 was 30 mm, and the narrowest width dimension of the absorber of the sample D using the cotton sheet was 14 mm. In the surface sheet 211 used for the sample C, even if the artificial menstrual blood is absorbed and the surface friction is applied, the constituent fibers 251 of the fiber web 250 do not adhere to each other, and twisting is unlikely to occur. In addition, in the cotton sheet used for the sample D, the width dimension of the absorber becomes small, and a large twist occurs. The reason for this is that the entanglement of cotton fibers is detached from each other due to surface friction, and the wrinkles formed during wearing, and the fibers after the entanglement detachment are attached to each other, forming a large groove extending in the longitudinal direction. Therefore.

Fig. 14 is an enlarged view of the cross-sectional shape of an example of the hydrophilic fiber, which is a different-shaped cross-sectional fiber. The hydrophilic fibers 260 are thermoplastic resin fibers subjected to hydrophilization treatment, such as hydrophilic PET fibers, and have a plurality of grooves 261 extending toward the extending direction. Since the hydrophilic fiber 260 has a plurality of grooves 261 extending in the extending direction, the surface area in contact with the menstrual blood becomes larger than that in the case where the outer peripheral surface is flat, and the inhalation of the menstrual blood can be improved.

In one example of another example of the present embodiment, as the material of the raw yarn of the fabric 240, unbleached pulp fibers that have not been subjected to lignin removal treatment at all can be used. In this case, since the unbleached pulp fiber containing a large amount of lignin has a light brown color derived from the natural material itself, the entire surface sheet 211 has a natural color tone of light brown. Since the surface sheet 211 has a light brown color, it is possible to give the wearer or the like an impression of a skin-friendly product using a natural material with a high degree of natural orientation. In addition, compared with the case of using a white sheet with bleaching treatment, the redness of the menstrual blood absorbed by the absorber 220 can be suppressed, and therefore, the juveniles who have just started menstruation can be less sensitive to menstruation due to the direct recognition of the menstrual blood. unease. In addition, since the lignin component has an excellent antibacterial effect, the sanitary napkin 210 can be worn and discarded more hygienically.

In addition, at least one of the first and second covering portions 225 and 226 of the core covering sheet 222 covering the liquid-absorbent core 221 may contain unbleached pulp fibers. In this case, together with the surface sheet 211 containing unbleached pulp fibers, a skin-friendly impression with a natural color tone can be imparted, and the concealability and antibacterial properties of menstrual blood can be contributed.

In this specification, as the liquid-permeable sheet for the absorbent article 210 of the second invention, the embodiment of the top sheet 211 arranged on the skin-opposing surface side of the absorber 220 has been described, but it can also be used as an absorbent sheet The sheet of the article 210 is used, for example, an intermediate sheet located on the inner surface side of the surface sheet, a core covering sheet, and the like. In addition, the absorbent article 210 is not limited to sanitary napkins, but can also include, for example, disposable diapers for adults and children, and urine-absorbing pads, and can also be used as a liquid-permeable sheet through which urine and soft stools can pass.

The disclosure of the second invention described above can be organized into at least the following matters. A liquid-permeable sheet for an absorbent article, comprising: a woven fabric having a first surface and a second surface opposite to each other in a thickness direction; and a fiber web entangled with the first surface of the woven fabric In the face-integrated fiber web, the constituent threads of the fabric are formed of continuous twisted yarns composed of cellulose fibers, and the fiber web includes hydrophilic fibers and hydrophobic fibers.

The liquid-permeable sheet for absorbent articles disclosed by the second invention includes the following embodiments. (1) The constituent yarns of the fabric comprising the twisted yarns include a plurality of warp yarns extending continuously, and a plurality of weft yarns extending continuously so as to intersect with the warp yarns in the thickness direction. (2) The content rate of the aforementioned hydrophobic fibers is higher than that of the aforementioned hydrophilic fibers. (3) The content rate of the said hydrophobic fiber is 51-90 mass %, and the content rate of the said hydrophilic fiber is 10-49 mass %. (4) The above-mentioned hydrophilic fibers are shaped in cross-section and have a plurality of grooves extending in the extending direction thereof. (5) The aforementioned fiber web and the aforementioned fabric are entangled by water flow, and the entanglement is integrated. (6) The fiber web is composed of short fibers, the fiber length of the short fibers is 25 to 64 mm, and the fineness is 0.8 to 6.0 dtex. The fineness of the aforementioned twisted yarn is 10 to 100 cotton yarn counts. (7) The said absorbent article is further provided with an absorber, and is arrange|positioned at the skin opposing surface side of the said absorber. (8) The fiber length of the short fibers is larger than at least one of the separation dimension of the adjacent and parallel warp yarns and the separation dimension of the adjacent and parallel weft yarns.

10: Absorbent articles (sanitary napkins) 11: Liquid-permeable sheet (surface sheet) 20: Absorber 40: Fabric 40a: 1st side (lower surface) 40b: Side 2 (upper surface) 41: Composition Line 45: Mesh 50: Fiber mesh 51: Constituent fibers 53: The part of the web extending from the second side of the fabric 60: Hydrophilic fiber 61: Groove D2: Thickness dimension of fabric D3: Thickness dimension of the portion of the fiber web extending from the second side Z: thickness direction 210: Absorbent articles (sanitary napkins) 211: Liquid-permeable sheet (surface sheet) 220: Absorber 240: Fabric 240a: 1st side (lower surface) 240b: Side 2 (upper surface) 241: Composition Line 245: mesh 250: Fiber Mesh 251: constituent fibers 260: Hydrophilic fiber 261: Groove R1: The separation dimension of the warp yarns adjacent to each other and parallel to each other R2: The separation dimension of the adjacent and parallel weft yarns Z: thickness direction

The drawings show specific embodiments of the first and second inventions, and include not only the structures essential to the invention but also optional and desirable embodiments. Fig. 1 is a plan view of a sanitary napkin which is an example of the absorbent article of the first invention as viewed from the surface side. Fig. 2 is a plan view of the sanitary napkin viewed from the back side. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1 . Fig. 4 is a partial enlarged view of a liquid-permeable sheet (surface sheet). Fig. 5 is a view showing a state in which the liquid-permeable sheet is separated into a fiber web and a fabric. FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 4 . Fig. 7 is an enlarged view of a hydrophilic fiber which is an example of a hydrophilic fiber. Fig. 8 is a plan view of a sanitary napkin which is an example of the absorbent article of the second invention as viewed from the surface side. Fig. 9 is a plan view of the sanitary napkin viewed from the back side. FIG. 10 is a cross-sectional view taken along line X-X of FIG. 8 . Fig. 11 is a partially enlarged view of a liquid-permeable sheet (surface sheet). Fig. 12 is a view showing a state in which the liquid-permeable sheet is separated into a fiber web and a fabric. FIG. 13 is a cross-sectional view taken along line XIII-XIII of FIG. 11 . Fig. 14 is an enlarged view of a hydrophilic fiber which is an example of a hydrophilic fiber.

11: Liquid-permeable sheet (surface sheet)

11a: Skin-opposite side (top)

11b: Non-skin-opposite side (below)

12: back sheet

14: Side Flakes

20: Absorber

20c: 1st lateral edge

20d: 2nd side edge

21: Absorbent core material

22: Core material cover sheet

22a, 22b: side edge

23: Overlap

25: The first covering part

26: The second covering part

31: Central area

40: Fabric

40a: 1st side (lower surface)

40b: Side 2 (upper surface)

45: Mesh

50: Fiber mesh

Claims (12)

A liquid-permeable sheet for an absorbent article, comprising: a woven fabric having a first surface and a second surface opposite to each other in a thickness direction; and a fiber web entangled with the first surface of the woven fabric The surfaces are integrated, and the constituent threads of the fabric are formed of cellulose fibers, and the constituent fibers of the fiber web are substantially the same surface as the second surface of the fabric, or extend outward in the thickness direction. A liquid-permeable sheet for an absorbent article, comprising: a woven fabric having a first surface and a second surface opposite to each other in a thickness direction; and a fiber web entangled with the first surface of the woven fabric The surface is integrated, the constituent threads of the fabric are formed by continuous twisted yarns composed of cellulose fibers, and the fiber web is composed of hydrophilic fibers and hydrophobic fibers. The liquid-permeable sheet for an absorbent article according to claim 1, wherein the constituent fibers of the fiber web comprise hydrophilic fibers and hydrophobic fibers. The liquid-permeable sheet for an absorbent article according to claim 1, wherein the thickness of the woven fabric is 1.1 to 4.0 times the thickness of the portion of the fiber web extending from the second surface of the woven fabric. . The liquid-permeable sheet for an absorbent article according to claim 1, 3, or 4, wherein a portion of the constituent fibers of the fiber web is the constituent thread of the fabric wound through a plurality of meshes of the fabric. It extends toward the second surface side. The liquid-permeable sheet for an absorbent article according to claim 2, wherein the constituent yarns of the fabric comprising the twisted yarns include: a plurality of warp yarns extending continuously; A plurality of wefts extending continuously so as to intersect each other in the thickness direction. According to the liquid-permeable sheet for an absorbent article according to claim 2 or 3, the content rate of the hydrophobic fibers is higher than the content rate of the hydrophilic fibers. The liquid-permeable sheet for an absorbent article according to claim 2 or 3, wherein the hydrophilic fiber has a cross-sectional profile and has a plurality of grooves extending in the extending direction. The liquid-permeable sheet for an absorbent article according to any one of Claims 1 to 4, wherein the fiber web and the fabric are treated by fluid entanglement, and the entanglement is integrated. The liquid-permeable sheet for an absorbent article according to claim 6, wherein the fiber web is composed of short fibers, and the fibers of the short fibers The length is 25~64mm, and the fineness is 0.8~6.0dtex. The aforementioned constituent thread of the aforementioned fabric is composed of twisted yarns formed by a plurality of original yarns, and the fineness of the aforementioned twisted yarns is 10~100 cotton yarn counts. The liquid-permeable sheet for an absorbent article according to any one of Claims 1 to 4, wherein the absorbent article further includes an absorber, which is disposed on the skin-facing surface side of the absorber. The liquid-permeable sheet for an absorbent article according to claim 10, wherein the fiber length of the short fibers is greater than the separation dimension of the adjacent and parallel warp yarns of the woven fabric and the adjacent and parallel weft yarns At least one of the separation dimensions from each other has a larger separation dimension.

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