TW202017543A - Liquid-permeable sheet for absorbent article - Google Patents

Abstract

Provided is a liquid-permeable sheet for an absorbent article that is highly liquid-permeable, has a required sheet strength, and is able to suppress re-wetting. The liquid-permeable sheet (11) of an absorbent article (10) is provided with: a fabric (40) having a first surface (40a) and a second surface (40b) opposing each other in a thickness direction (Z); and a fiber web (50) integrated with the first surface (40a) of the fabric (40) by interlacing. A constituent thread (41) of the fabric (40) is formed of cellulose-based fibers, and constituent fibers (51) of the fiber web (50) are substantially flush with the second surface (40b) of the fabric (40) or extend on the outside in the thickness direction.

Description

Liquid-permeable sheet for absorbent articles

The present invention relates to a liquid-permeable sheet for absorbent articles, and more specifically, to a slightly incontinent pad, panty liner, physiological sanitary napkin, secretory absorption pad, urine absorption pad, adult and Liquid-permeable sheets for absorbent articles such as disposable paper diapers for children.

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

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

The absorbent article disclosed in Patent Document 1 has a plurality of openings in the surface sheet, so that the body fluid can quickly move from the skin-facing surface of the absorbent article to the absorbent body.

[Problems to be solved by the invention]

(Problem of the first invention) However, the surface sheet is formed with a plurality of openings, resulting in a low strength of the sheet, which may curl or partly break during wearing. In addition, there is a possibility that the body fluid absorbed by the absorber may return to the front side of the top sheet through the opening.

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

(Problem of the second invention) The surface sheet of Patent Document 1 is formed with a plurality of openings, resulting in low sheet strength, which may curl or partially break during wearing. In addition, since they are formed of hydrophilic fibers, the hydrophilic fibers absorb menstrual blood and swell, which further weakens the strength of the sheet. Therefore, menstrual blood adhering to the skin cannot be scraped at the opening of the surface sheet. In addition, in order to prevent the occurrence of such a defect, when the surface sheet is formed of hydrophobic fibers, the body fluid cannot be sufficiently inhaled.

In addition, since the sheet strength of the surface sheet is low, when the sanitary napkin is taken out from the individual packaging bag stored in the folded state, a crease is easily formed. When the sanitary napkin is adhered to the undergarment, part of it Floating from the undergarment may cause lateral leakage of menstrual blood and a deterioration in wearing feeling.

The second invention is an improvement of the conventional invention, and its object is to provide a liquid-permeable sheet for absorbent articles which has excellent liquid permeability and has the required sheet strength and can suppress moisture regain. [Means to solve the problem]

In the first invention, a liquid-permeable sheet for absorbent articles is provided with: a fabric having a first surface and a second surface facing in the thickness direction; and a fibrous web, which is formed by entanglement, and A fiber web integrated with the first surface of the fabric, the constituent yarns of the fabric are formed of cellulose-based fibers, and the constituent fiber system of the fiber mesh is substantially the same as the surface of the second surface of the fabric, or more oriented The aforementioned outer side extending in the thickness direction exists.

In a second invention, a liquid-permeable sheet for absorbent articles includes: a fabric having a first surface and a second surface facing in the thickness direction; and a fiber web, which is formed by entanglement, and In the fibrous web integrated on the first surface of the woven fabric, the constituent yarns of the woven fabric are formed of continuous twisted yarns composed of cellulose-based fibers, and the fibrous web system includes hydrophilic fibers and hydrophobic fibers. [Effect of the invention]

In the liquid-permeable sheet for absorbent articles of the first invention, the surface sheet has a skin-like skin feel, which can achieve a good absorption rate of body fluids and suppress the phenomenon of moisture regain. In the liquid-permeable sheet for absorbent articles of the second invention, the surface sheet has a skin-like skin feel, and the excrement has good scraping properties, and it is not easy to form creases, which can suppress lateral leakage of body fluid and decrease the wearing feeling.

(1st invention)

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

As shown in FIGS. 1 to 3, the sanitary napkin 10 has a longitudinal center line P that bisects the size in the width direction and a transverse center line Q that bisects the size in the length direction, and includes: the skin-facing surface The (inner surface) side and the non-skin facing surface (outer surface) side of the opposite side; the convex and curved first and second end edges 10a, 10b; the central portion where the horizontal center line Q exists, forming the convex and curved 1 and the second side edges 10c, 10d; the liquid-permeable top sheet 11 on the opposite side of the skin; the liquid-impermeable back sheet 12 on the non-skin opposite side; and between these two sheets 11, 12之液absorbing absorber 20. The surface sheet 11 and the absorber 20 are bonded to each other by a conventional bonding method such as hot-melt adhesive, to form the liquid-absorbing layer 13.

In addition, although not shown, in order to improve the flexibility of the sanitary napkin 10, an intermediate sheet made of fibrous nonwoven fabric with high bulkiness may be arranged between the surface sheet (liquid-permeable sheet) 11 and the absorber 20. In addition, between the absorber 20 and the back sheet 12, in order to suppress leakage of body fluids, a leak-proof sheet that is preferably air-permeable and composed of a liquid-impermeable fiber nonwoven fabric or a plastic film may also be disposed.

The absorber 20 has a first end edge 20a facing the first end edge 10a and a second end edge 20b facing the second end edge 10b; and between the first and second end edges 20a and 20b, The first and second side edges 20c and 20d extending in the longitudinal direction Y. The front and back sheets 11 and 12 extend from the outer periphery of the absorber 20 to the outside. On the skin facing 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侧片14. The pair of side sheets 14 are bonded to the surface sheet 11 via a conventional bonding means or side bonding portions (not shown) formed by welding means. Although not shown, in the side sheet 14, in order to form a leak-proof wall that rises toward the body side in the wearing state, an elastic material extending in the longitudinal direction Y may be arranged to be contractible in the extended state. In addition, the side joint portion for fixing the side sheet 14 may be a seal line extending in the longitudinal direction Y having design elements such as floral patterns or geometric patterns.

The sanitary napkin 10 includes a top sheet 11, a back sheet 12, and a side sheet 14, which extend outside the longitudinal direction Y of the first and second end edges 20a, 20b of the absorber 20 and extend in the lateral direction X Both end portions 16; and both side edge portions 17 extending in the longitudinal direction Y outside the first and second side edges 20c, 20d of the absorber 20 in the lateral direction X. In the central portion of the sanitary napkin 10 in the longitudinal direction Y, there is a fin portion 18 that is convex toward the outside in the lateral direction X and is formed by a part of both side edge portions 17. In addition, the sheets 11, 12, and 14 stacked on each other are joined to each other via an outer peripheral seal portion 19 that exists 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 fixation areas 30 are used to fix the sanitary napkin 10 on clothing such as undergarments, and are formed by applying a plurality of linear adhesives extending in the longitudinal direction Y, pressure-sensitive adhesives, etc. . The fixing region 30 has a central region 31 extending in the longitudinal direction Y in a region overlapping the absorber 20; and a side region 32 located in the fin portion 18. The fixing area 30 is covered by a separator (not shown) made of plastic film.

The surface sheet 11 is liquid-permeable, and has a skin-facing surface (upper surface) 11a and a non-skin-facing surface (lower surface) 11b located on the opposite side thereof, and is formed of a laminated sheet of the 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 fibrous nonwoven fabric, such laminated sheets, and the like. As the side sheet 14, a conventional non-woven fabric can be used. However, in order to effectively prevent lateral leakage of body fluid, it is preferable to use a sheet material having hydrophobicity or water repellency.

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

As shown in FIGS. 3 and 4, the absorber 20 has a liquid-absorbent core material in which superabsorbent polymer particles (SAP) are mixed with cellulose-based fibers such as fluff wood pulp and rayon fibers and shaped into a predetermined shape. 21; and in order to improve its shape retention and liquid diffusivity, the liquid-permeable core material 21 covering the entire liquid-absorbent core material 21 covers the sheet 22.

The longitudinal dimension Y of the core covering sheet 22 is larger than the longitudinal dimension Y of the liquid-absorbent core material, and the two side edges 22a and 22b are used to cover the entire liquid-absorbent core material 21, The bottom surface side of the central portion of the core material 21 in the lateral direction X exists so as to overlap each other. By folding the two side edges 22a and 22b with each other, an overlapping portion formed by stacking the two side edges 22a and 22b in the longitudinal direction Y at the center of the absorber 20 in the horizontal direction X is formed twenty three.

The core material cover sheet 22 has a first covering portion 25 covering the skin-facing surface side of the liquid-absorbent core material 21 and a second covering portion 26 covering the non-skin-facing surface side of the liquid-absorbing core material 21. In the present embodiment, the core material cover sheet 22 is formed by one continuous sheet. However, the first core material cover sheet forming the first covering portion 25 and a body different from the first core material cover sheet may also be used. The second core material forming sheet forming the second covering portion 26 is configured.

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: a fabric 40 on the side opposite to the skin; and a fiber web 50 on the side opposite to the skin. 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. The fabric 40 and the fiber web 50 are integrated by being entangled with each other. Furthermore, depending on the wearing state of the absorbent article, the upper surface 40b of the fabric 40 may be located below and the lower surface 40a may be located above.

The fabric 40 is composed of mesh-forming constituent threads 41. The constituent wire 41 includes a plurality of warp yarns 42 and a plurality of weft yarns 43 that intersect each other with the warp yarns 42. The warp yarns 42 and the weft yarns 43 cross each other in the thickness direction Z to form a plurality of meshes 45. The constituent yarn 41 of the woven fabric 40 is a twisted yarn formed by twisting a raw yarn formed of cotton yarn (cotton fiber). As the material of the raw yarn, in addition to cotton fibers, cellulose-based fibers such as natural cellulose fibers such as pulp fibers, regenerated cellulose fibers such as rayon, and semi-synthetic cellulose fibers such as acetate 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, cellulose-based fibers, and a mixture of these fibers can be used as appropriate. The number of yarns (sum of warp yarns and weft yarns) constituting the thread 41 is 60 to 100, and the cotton yarn used as the raw yarn is preferably a cotton yarn count of 10 to 100 in thickness.

The fiber web 50 is formed by a conventional manufacturing method such as a spun bond method using long fibers, a dry method in which staple fibers are aligned in a certain direction to form a mesh, and is formed into a fiber assembly at a stage before nonwoven fabric That is, it is formed by the constituent fibers 51 including hydrophilic fibers and hydrophobic fibers. Hydrophobic fibers, in addition to the use of polyolefin-based thermoplastic fibers containing polypropylene (PP) and polyethylene (PE), polyester-based thermoplastic fibers containing polyethylene terephthalate (PET), etc. In addition to single fibers, various composite fibers such as core-sheath composite fibers, side-by-side composite fibers, sea-island composite fibers, and the like can also be used.

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

As a method of entanglement and integration of the fabric 40 and the fiber web 50, for example, a conventional fluid entanglement method can be used. In the manufacturing process of the liquid-permeable sheet by the fluid entanglement method, a continuous laminate composed of a continuous fiber web as the material of the fiber web 50 is laminated on the upper surface of the continuous network structure as the material of the fabric 40 The plurality of nozzles are arranged at intervals from the upper side in a direction intersecting the direction of conveyance of the continuous laminate to spray fluids such as gas, water, etc. at high pressure, whereby the fibers (including long Fibers and short fibers) and the continuous network constitute the thread entangled and integrated.

The continuous lamination system is conveyed by a conveying means composed of a metallic mesh belt. When a fluid is sprayed from the nozzle onto the upper surface of the continuous laminate, the fibers of the continuous fiber web and the continuous web are on the upper surface side The structural line of the structure is entangled, and on the lower surface side facing the conveyance means, the fluid rebounded by the collision with the conveyance means is also entangled. Since the surface sheet 11 winds the fiber web 50 formed by the fiber assembly to the fabric 40 by the fluid entanglement method, compared with the case where the non-woven sheet is laminated and then fluidly entangled, the fiber web 50 The constituent fibers 51 are easily entangled in the woven fabric 40, and the stacked state can be maintained more stably. In addition, according to the fluid entanglement treatment method, by appropriately changing the structure of the mesh belt of the conveying means, the surface sheet 11 having desired sheet characteristics can be obtained with respect to thickness, mass, absorption speed, sheet strength, and the like.

The surface sheet 11 is formed by integrating the fabric 40 located on the side opposite to the skin with the fiber web 50 located on the side opposite to the skin. Therefore, compared to the case where the surface sheet 11 is formed of only non-woven fabric, It has higher strength and can give the fabric a soft texture. In addition, since the fabric 40 has a mesh structure, the contact area with the skin can be reduced, and a dry touch can be imparted.

The menstrual blood excreted in the surface sheet 11 spreads along the warp yarns 42 and the weft yarns 43 of the fabric 40, and moves along the constituent fibers 51 of the fiber web 50 extending downward from the mesh 45 of the fabric 40 toward the absorbent body 20 downward. Furthermore, compared to the case where the surface sheet 11 is formed of a liquid-permeable fiber nonwoven fabric, even if the sheet quality is the same, by having the constituent fibers 51 of the fiber web 50, the mesh shape formed by the constituent threads 41 having a larger fineness The fabric 40 makes the sheet more rigid. Thereby, the surface sheet 11 can be effectively prevented from curling, floating, and the like from the absorber 20.

In the case where the surface sheet is only formed of non-woven fabric containing hydrophilic fibers, due to the good absorption speed and liquid diffusivity, even if the amount of menstrual blood excretion is small, it will quickly spread to a wide range and stain the skin, which may cause skin problems. s reason. In this embodiment, the surface sheet 11 is formed by the laminated sheet of the fabric 40 and the fiber web 50, and menstrual blood is not easily diffused along the constituent lines of the fabric 40. When the amount of excretion is small, it forms point-like absorption, so it can be suppressed A condition in which skin is contaminated by a wide area and causes skin problems.

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

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

The body fluid excreted on the surface sheet 11 is absorbed and diffused by the hydrophilic fibers contained in the upper extension 53 of the fiber web 50, and diffuses in the longitudinal direction Y and the lateral direction X by the warp yarn 42 and the weft yarn 43 of the fabric 40, rapidly移行到absorbing body 20. At this time, since a part of the fiber web 50 is substantially the same plane as or located above the upper surface 40b of the fabric 40, it can be close to the skin to increase the menstrual blood absorption area, and more menstrual blood can be inhaled. In addition, by partially locating the fiber web 50 containing hydrophobic fibers above the upper surface 40b of the fabric 40, it is possible to suppress the so-called resurgence phenomenon in which body fluids absorbed and held by the fabric 40 and the absorber 20 return due to body pressure or the like ( Rewet back).

Since the fabric 40 is composed of a plurality of warp yarns 42 continuously extending and a plurality of weft yarns 43 continuously extending in the thickness direction Z so as to cross the warp yarns, it is not easy to cause direct contact with the skin and wear When being loaded with body pressure or in contact with menstrual blood, its strength decreases, and it is not easy to produce hairballs and slack.

Since the fabric 40 is located closer to the skin than the fiber web 50, the constitution thread 41 having a larger denier than the fiber 51 of the fiber web 50 and a high rigidity can scrape menstrual blood adhering to the skin. Especially when the menstrual blood is in contact with air and hardens with time, it adheres to the skin and sticks to the skin. Therefore, in the past, only the surface sheet made of non-woven fabric with soft fiber slipping cannot be scraped. However, by being Applying the carrier pressure and contacting the fabric 40, which does not easily reduce menstrual blood strength, directly or indirectly contacts the skin, so that the plurality of meshes 45 can also wipe the menstrual blood that adheres to the skin tightly. In addition, in the case where the constituent thread 41 of the woven fabric 40 is formed of twisted yarn, since the entire outer peripheral surface is convex and concave, the scrapability 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. In the case where the thickness dimension D3 relatively has this dimension, it is possible to achieve both scraping properties and suppression of the moisture regain phenomenon at the same time. That is, in the case where the thickness dimension D3 is less than 1.1 times the thickness dimension D2, although the fabric 40 becomes closer to the skin, the scraping property becomes higher, but only the portion of the fiber web 50 is thinner, so there is no way to borrow The fiber web 50 containing hydrophobic fibers effectively suppresses the moisture regain phenomenon. In addition, in the case where the thickness dimension D3 exceeds 4.0 times the thickness dimension D2, the upper extension 53 of the thicker fiber web 50 can suppress the moisture regain phenomenon and can absorb body fluid along the constituent fibers 51, but due to the fabric 40 is located away from the skin, so it becomes difficult to scrape the menstrual blood attached to the skin.

<Measurement method of thickness> Here, the thickness dimension D2 of the fabric 40 is in the state of the material, and is measured using a gauge with a diameter of 50 mm [PEACOCK dial thickness gauge (Dial thickness gauge J-B manufactured by Ozaki Corporation)]. In addition, the thickness D1 of the surface sheet 11 is the thickness of the appearance. As shown in FIG. 6, the surface sheet 11 is ideally cut along the machine direction of the fiber web 50, and cut using a digital microscope VHX-1000 manufactured by Keynes, etc. The enlarged photo of the surface is taken, and the maximum thickness of the surface sheet 11 is measured based on the enlarged photo. The same measurement is performed at five randomly designated locations and the average value is obtained. This average value is used as the thickness dimension of the surface sheet 11 D1. The thickness D1 of the surface sheet 11 minus the thickness D2 of the fabric 40 and the thickness of the lower extension 52 is taken as the thickness of the upper extension 53 of the fiber web 50 (from the upper surface 40b of the fabric 40 The separation size D3 of the apex 53a of the upper extending portion 53. In addition, the measurement operation is 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 small thickness dimension D3; and a plurality of high bulkiness portions 55 having a large thickness dimension D3. Since the lower extending portion 52 of the fiber web 50 has a concave-convex shape, the menstrual blood adhering to the skin can be effectively scraped together with the fabric 40 located below.

In addition, in the case where the surface sheet 11 is formed by the fluid entanglement method, in the lower extension portion 52 that directly collides with the high-pressure jetted fluid, the portion of the fiber web 50 that directly collides with the fluid ejected from the nozzle is compared with other portions , Its fluffiness is low. The low bulkiness portion 56 includes a portion where the fluid directly collides. In this case, the low bulkiness portion 56 has a higher fiber density than the high bulkiness portion 57. Therefore, the body fluid traveling from the fabric 40 toward the downward extending portion 52 can move to the absorbent body located below at a lower bulkiness portion 56 having a higher fiber density than a high bulkiness portion 57.

The fibrous web 50 is integrated with the fabric 40 by entanglement without passing through an adhesive or the like. Therefore, it is more flexible than cases where they are joined to each other via an adhesive or the like. As the constituent fibers 51 of the fiber web 50 are entangled with the fabric 40, in addition to a part of the constituent fibers 51 being entangled or wound by the warp and weft yarns of the fabric 40, there may be a part of the constituent fibers 51 It is entangled so as to enter between the warp yarn 42 formed by the twisted yarn and the original yarn of the weft yarn 43. In this way, the constituent fibers 51 are wound around the outer and inner surfaces of the warp yarn 42 and the weft yarn 43, so that the fiber web 50 can be stably integrated into the fabric 40.

The fiber 51 of the fiber web 50 has a fineness of 0.8 to 6.0 dtex, preferably 1.0 to 4.4 dtex, more preferably 1.3 to 3.3 dtex; a fiber length of 25 to 64 mm, ideally 32 to 58 mm, and more ideally 38 to 51 mm The staple fiber composed of twisted yarn has a fineness of 10 to 100 cotton counts, preferably 20 to 60 cotton counts, and more preferably 30 to 45 cotton counts. 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 the gap between the twists of the original yarn having a larger denier or are wound It is tightly wound around the constituent thread 41, so that the fiber web 50 can be stably wrapped 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 size R1 of the warp yarns 42 adjacent to each other and parallel and the separation size R2 of the weft yarns 43 adjacent to each other. The separation size is larger. In this case, no short fibers fall out of the mesh 45 of the fabric 40, and by extending the short fibers across the mesh 45, the sheet strength and liquid diffusivity of the entire surface sheet 11 can be improved.

The content rate of the hydrophilic fiber in the fiber web 50 is less than 50% by mass, preferably 10 to 49% by mass, and the content rate of the hydrophobic fiber is more than 50% by mass, ideally 51 to 90% by mass. The proportion of hydrophobic fibers is higher than that of hydrophilic fibers. With a higher proportion of hydrophobic fibers, it can suppress diffusibility and can suppress the phenomenon of moisture regain.

In addition, when the content rate of the hydrophilic fiber is less than 10% by mass, the proportion of the hydrophobic fiber is relatively increased, and although the moisture regain phenomenon can be suppressed, the inhalability of menstrual blood drawn from the skin decreases. In addition, in the case where the content rate of the hydrophilic fiber is 50% by mass or more, although more menstrual blood is absorbed more quickly, the phenomenon of moisture regain is likely to occur. In the surface sheet 11, by containing hydrophilic fibers and hydrophobic fibers in a balanced manner, it is possible to achieve good liquid absorption, liquid diffusibility, and suppression of moisture regain.

FIG. 7 is an enlarged view of an irregular-shaped cross-sectional fiber having a different cross-sectional shape as an example of hydrophilic fibers. The hydrophilic fiber 60 is a thermoplastic resin fiber subjected to hydrophilization treatment, for example, hydrophilic PET fiber, and has a plurality of grooves 61 extending in 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 menstrual blood becomes larger than when the outer peripheral surface is flat, and the inhalation of menstrual blood can be improved.

In an example of other embodiments of the present embodiment, as the raw material of the fabric 40, unbleached pulp fibers that have not been subjected to lignin removal treatment at all may be used. In this case, the unbleached pulp fiber containing much lignin component has a light brown color derived from the natural material itself, so the entire surface sheet 11 has a light brown natural hue. Since the surface sheet 11 has a light brown color, it is possible to give the wearer and the like the impression of a skin-oriented and highly natural product using natural materials. In addition, compared with the case where a white sheet with bleaching treatment is used, the redness of menstrual blood absorbed by the absorber 20 can be suppressed, and therefore, it is possible to alleviate the minor men who have just come to menstruation from having menstrual blood Anxiety. Moreover, since the lignin component has an excellent antibacterial effect, the sanitary napkin 10 for physiological use can be worn and discarded more hygienically.

Furthermore, 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, it is possible to give a skin-friendly impression with a natural hue together with the surface sheet 11 containing unbleached pulp fibers, and it can contribute to the concealment and antibacterial properties of menstrual blood.

In this specification, the liquid-permeable sheet for the absorbent article 10 of the first invention has been described with respect to the embodiment of the surface sheet 11 disposed on the skin-facing side of the absorber 20, but it can also be used as an absorbent sheet. The sheet of the article 10 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 10 is not limited to sanitary napkins, and may include, for example, paper diapers for adults and children, and urine absorption pads, and may also be used as a liquid-permeable sheet through which urine and soft stool 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 in a thickness direction; and a fiber web integrated with the first surface of the fabric by entanglement In the fiber web, the constituent yarns of the woven fabric are formed of cellulose fibers. The constituent fiber systems of the woven fabric are substantially the same as the second surface of the woven fabric, or extend more outward than the thickness direction of the woven fabric.

The liquid-permeable sheet for absorbent articles of the first invention described above includes the following embodiments. (1) For the thickness dimension of the fabric, the thickness dimension of the portion of the fiber web extending from the second surface of the fabric is 1.1 to 4.0 times. (2) A part of the constituent fibers of the fiber web is wound around the constituent threads of the woven fabric, and extends toward the second surface side through a plurality of meshes of the woven fabric. (3) The constituent fiber system of the fiber web includes hydrophilic fibers and hydrophobic fibers, and the content rate of the hydrophobic fibers is higher than the content rate of the hydrophilic fibers. (4) The aforementioned hydrophilic fiber is irregular in cross-section and has a plurality of grooves extending in the extending direction. (5) The fiber web and the fabric are integrated by fluid entanglement treatment. (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, and the constituent threads of the woven fabric are composed of twisted yarns formed from a plurality of raw yarns The fineness of the twisted yarn is 10 to 100 counts of cotton yarn. (7) The absorbent article further includes an absorber, and is disposed on the skin-facing side of the absorber. (8) The fiber length of the short fibers is larger than at least one of the separation size of the warp yarns adjacent to each other and parallel, and the separation size of the weft yarns adjacent to each other parallel.

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

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

In addition, although not shown, in order to improve the flexibility of the sanitary napkin 210, an intermediate sheet made of fibrous nonwoven fabric with high bulkiness may be arranged between the surface sheet (liquid-permeable sheet) 211 and the absorber 220. In addition, between the absorber 220 and the back sheet 212, in order to suppress leakage of body fluids, a leak-proof sheet that is preferably air-permeable and composed of a liquid-impermeable fibrous nonwoven fabric or a plastic film may also be disposed.

The absorber 220 has a first end 220a facing the first end 210a and a second end 220b facing the second end 210b; and between the first and second end 220a, 220b, The first and second side edges 220c and 220d extend in the longitudinal direction Y. The front and back sheets 211 and 212 extend from the outer periphery of the absorber 220 to the outside. On the skin facing surface side of the top sheet 211, a pair extending in the longitudinal direction Y is arranged so as to face each other in the lateral direction X侧片214. The pair of side sheets 214 are bonded to the surface sheet 211 via a conventional bonding means or a side bonding portion (not shown) composed of welding means. Although not shown, in the side sheet 214, in order to form a leak-proof wall that rises toward the body side in the wearing state, an elastic material extending in the longitudinal direction Y may be contractibly arranged in the extended state. In addition, the side joint portion for fixing the side sheet 214 may be a seal line extending in the longitudinal direction Y having design elements such as floral patterns or geometric patterns.

The sanitary napkin 210 includes a top sheet 211, a back sheet 212, and a side sheet 214, and extends outside the longitudinal direction Y of the first and second end edges 220a, 220b of the absorber 220, and extends in the lateral direction X Both end portions 216; and both side edge portions 217 extending in the longitudinal direction Y outside the first and second side edges 220c, 220d of the absorber 220 in the lateral direction X. In the central portion of the sanitary napkin 210 in the longitudinal direction Y, there is a tab portion 218 that is convex toward the outside in the lateral direction X and is formed by a part of both side edge portions 217. In addition, the sheets 211, 212, and 214 stacked on each other are joined to each other via an outer peripheral seal portion 219 that exists along the outer peripheral edge of the sanitary napkin 210.

As shown in FIG. 9, a plurality of fixing regions 230 are arranged on the back side of the sanitary napkin 210. The plurality of fixing regions 230 are used to fix physiological sanitary napkins 210 on clothing such as undergarments, and are formed by applying a plurality of linear adhesives extending in the longitudinal direction Y, pressure-sensitive adhesives, etc. . 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 fin portion 218. The fixing area 230 is covered with a separator (not shown) made of plastic film.

The surface sheet 211 is liquid-permeable, has a skin-facing surface 211a and a non-skin-facing surface 211b located on the opposite side, and is formed of a laminated sheet of a fabric 240 and a fiber web 250. In addition, the back sheet 212 may be formed of a liquid-impermeable and moisture-permeable plastic film, a liquid-impermeable fibrous nonwoven fabric, such laminated sheets, and the like. As the side sheet 214, a conventional non-woven fabric can be used. However, in order to effectively prevent lateral leakage of body fluid, it is preferable to use a sheet material having hydrophobicity or water repellency.

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

As shown in FIGS. 10 and 11, the absorber 220 has a liquid-absorbent core material in which superabsorbent polymer particles (SAP) are mixed with cellulose-based fibers such as fluff wood pulp and rayon fibers and shaped into a predetermined shape. 221; and in order to improve its shape retention and liquid diffusivity, the liquid-permeable core material covering the entire liquid-absorbent core material 221 covers the sheet 222.

The longitudinal dimension Y of the core covering sheet 222 is larger than the longitudinal dimension Y of the liquid-absorbent core material, and both side edge portions 222a and 222b are designed to cover the entire liquid-absorbent core material 221, The bottom surface side of the central portion of the core material 221 in the lateral direction X exists so as to overlap each other. By folding the two side edges 222a and 222b with each other, an overlapping portion formed by stacking the two side edges 222a and 222b in the longitudinal direction Y at the center of the absorber 220 in the horizontal direction X is formed 223.

The core material cover sheet 222 has a first covering portion 225 covering the skin-facing 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-absorbing core material 221. In this embodiment, the core material cover sheet 222 is formed by one continuous sheet, but the first core material cover sheet forming the first covering portion 225 and a body different from the first core material cover sheet may also be used. The second core material forming sheet forming the second covering portion 226 is configured.

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: a fabric 240 on the side opposite to the skin; and a fiber web 250 on the side opposite to the skin. 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 fiber web 250 are integrated by being entangled with each other. Furthermore, depending on the wearing state of the absorbent article, the upper surface 240b of the fabric 240 may be located below and the lower surface 240a may be located above.

The fabric 240 is composed of mesh-forming constituent threads 241. The constituent line 241 has a plurality of warp yarns 242 and a plurality of weft yarns 243 that intersect with the warp yarn 242. The warp yarns 242 and the weft yarns 243 cross each other in the thickness direction Z to form a plurality of meshes 245. The constituent yarn 241 of the woven fabric 240 is a twisted yarn formed by twisting a raw yarn formed of cotton yarn (cotton fiber). As the material of the raw yarn, in addition to cotton fibers, cellulose-based fibers such as natural cellulose fibers such as pulp fibers, regenerated cellulose fibers such as rayon, and semi-synthetic cellulose fibers such as acetate 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, cellulose-based fibers, and a mixture of these fibers can be used as appropriate. The number of yarns (the sum of warp yarns and weft yarns) constituting the thread 241 is 60 to 100. As the cotton yarn used as the raw yarn, a cotton yarn count of 10 to 100 in thickness can be preferably used.

The fiber web 250 is formed by a conventional manufacturing method such as a spun-bonding method using long fibers, a dry method in which staple fibers are aligned in a certain direction to form a mesh, and is formed into a fiber assembly at a stage before nonwoven fabric. , That is, it is formed by the constituent fibers 251 including hydrophilic fibers and hydrophobic fibers. Hydrophobic fibers, in addition to the use of polyolefin-based thermoplastic fibers containing polypropylene (PP) and polyethylene (PE), polyester-based thermoplastic fibers containing polyethylene terephthalate (PET), etc. In addition to single fibers, various composite fibers such as core-sheath composite fibers, side-by-side composite fibers, sea-island composite fibers, and the like can also be used.

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

As a method of entangling and integrating the fabric 240 and the fiber web 250, for example, a conventional fluid entanglement treatment method can be used. In the manufacturing process of the liquid-permeable sheet by the fluid entanglement treatment method, a continuous layer composed of a continuous fiber web which is a material of the fiber web 250 is laminated on the upper surface of a continuous network structure which is a material of the fabric 240 The integrated body, from the upper side, a plurality of nozzles arranged at intervals from the direction intersecting the conveying direction of the continuous laminated body, jetting fluids such as gas, water, etc. at high pressure, whereby the fibers of the continuous web (including Long fibers and short fibers) and the continuous network constitute the thread entangled and integrated.

The continuous lamination system is conveyed by a conveying means composed of a metallic mesh belt. When a fluid is sprayed from the nozzle onto the upper surface of the continuous laminate, the fibers of the continuous fiber web and the continuous web are on the upper surface side The structural line of the structure is entangled, and on the lower surface side facing the conveyance means, the fluid rebounded by the collision with the conveyance means is also entangled. Since the surface sheet 211 winds the fiber web 250 formed by the fiber assembly to the fabric 240 by the fluid entanglement method, compared to the case where the nonwoven sheet is laminated and then fluidly entangled, the fiber web 250 The constituent fibers 251 are easily entangled in the fabric 240, and can be stacked in a more stable state. In addition, according to the fluid entanglement treatment method, by appropriately changing the structure of the mesh belt of the conveying means, the surface sheet 211 having desired sheet characteristics can be obtained with respect to thickness, mass, absorption speed, sheet strength, and the like.

The surface sheet 211 is formed by entanglement, and the fabric 240 located on the side opposite to the skin is integrated with the fiber web 250 located on the side opposite to the skin. Therefore, compared to the case where the surface sheet 211 only travels by a non-woven fabric, It has higher strength and can give the fabric a soft texture. In addition, since the fabric 240 has a mesh structure, the contact area with the skin can be reduced, and a dry touch can be imparted.

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 moves along the constituent fibers 251 of the fiber web 250 extending downward from the mesh 245 of the fabric 240 toward the absorbent body 220 downward. Moreover, compared to the case where the surface sheet 211 is formed of a liquid-permeable fiber nonwoven fabric, even if the sheet quality is the same, by having the constituent fibers 251 than the fiber web 250, the mesh shape formed by the constituent threads 241 having a larger fineness The fabric 240 makes the sheet more rigid. With this, the surface sheet 211 can be effectively prevented from curling, floating, and the like from the absorber 220.

Generally, the surface sheet used for sanitary napkins is relatively thin and contains a large amount of hydrophilic fibers. Therefore, fibers that swell after absorbing menstrual blood become easily sticky. Therefore, there is a possibility that a crease may be formed when the sanitary napkin is folded and stored in an individual package. When the sanitary napkins with creases are attached to close-fitting clothing, etc., a gap may be formed between a part of the sanitary napkins and the body, which may cause lateral leakage of menstrual blood and decrease the sense of wearing.

Since the surface sheet 211 contains hydrophilic fibers and hydrophobic fibers, and the ratio of hydrophobic fibers is higher than that of hydrophilic fibers, it is possible to suppress the formation of creases caused by the fibers sticking to each other. In addition, the surface sheet 211 is located on the side opposite to the skin (inner surface) by the fabric 240 having a higher rigidity than sheet materials such as nonwoven fabric, and is less likely to cause creases. Therefore, when the sanitary napkin is taken out from the individual package housed in the folded state, 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 only formed of non-woven fabric containing hydrophilic fibers, due to the good absorption speed and liquid diffusivity, even if the amount of menstrual blood excretion is small, it will quickly spread to a wide range and stain the skin, which may cause skin problems. s reason. In this embodiment, the surface sheet 211 is formed by a laminated sheet of the fabric 240 and the fiber web 250, and menstrual blood is not easily diffused along the constituent lines of the fabric 240. When the amount of excretion is small, a point-shaped absorption is formed, so it can be suppressed A condition in which skin is contaminated by a wide area and causes skin problems.

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

That is, a part of the fiber web 250 starts from the fabric 240, is on the same plane as the upper surface 240b, or is located above it. In the case where the surface sheet 211 is formed by the fluid entanglement method, the lower extension portion 252 of the fiber web 250 is a continuous fiber web where fluid is jetted at high pressure, and the upper extension portion 253 is a part of the constituent fibers of the continuous fiber web penetrating below The continuous mesh body of the material of the fabric 240 extends toward the mesh belt side as a conveying means.

The body fluid excreted on the surface sheet 211 is absorbed and diffused by the hydrophilic fibers contained in the upper extending portion 253 of the fiber web 250, and diffuses in the longitudinal direction Y and the lateral direction X by the warp yarn 242 and the weft yarn 243 of the fabric 240, rapidly移行到absorbing body 220. At this time, since a part of the fiber web 250 is substantially the same as or is located above the upper surface 240b of the fabric 240, it can approach the skin and increase the menstrual blood absorption area, so that more menstrual blood can be inhaled. In addition, because a part of the fiber web 250 containing hydrophobic fibers is located above the upper surface 240b of the fabric 240, it is possible to suppress the so-called moisture regain phenomenon of the body fluid absorbed and held by the fabric 240 and the absorbent body 220 due to body pressure and the like (Rewet) back) produced.

Since the fabric 240 is composed of a plurality of warp yarns 242 that continuously extend and a plurality of weft yarns 243 that continuously extend in the thickness direction Z so as to intersect with the warp yarns, it is not easy to cause direct contact with the skin and wear When being loaded with body pressure or in contact with menstrual blood, its strength decreases, and it is not easy to produce hairballs and slack.

Since the fabric 240 is located closer to the skin than the fiber web 250, the menstrual blood adhering to the skin can be scraped by the component thread 241 having a larger denier than the fiber 251 of the fiber web 250 and a high rigidity. Especially when the menstrual blood is in contact with air and hardens with time, it adheres to the skin and sticks to the skin. Therefore, in the past, only the surface sheet made of non-woven fabric with soft fiber slipping cannot be scraped. However, by being Applying the carrier pressure and contacting the fabric 240 with which the strength of menstrual blood does not easily decrease directly or indirectly contacts the skin, so that the plurality of meshes 245 can also be used to wipe the menstrual blood adhered to the skin tightly. In addition, in the case where the constituent thread 241 of the woven fabric 240 is formed of twisted yarn, since the entire outer peripheral surface is convex and concave, the scrapability 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. In the case where the thickness dimension D3 relatively has this dimension, it is possible to achieve both scraping properties and suppression of the moisture regain phenomenon at the same time. That is, when the thickness dimension D3 is less than 1.1 times the thickness dimension D2, although the fabric 240 becomes closer to the skin, the scrapability becomes higher, but only the portion of the fiber web 250 is thinner, so there is no way to borrow The moisture regain phenomenon is effectively suppressed by the fiber web 250 containing hydrophobic fibers. In addition, in the case where the thickness dimension D3 exceeds 4.0 times the thickness dimension D2, the upper portion 253 of the thick fiber web 250 can suppress the moisture regain phenomenon and can absorb body fluids along the constituent fibers 251. However, due to the fabric 240 is located away from the skin, so it becomes difficult to scrape the menstrual blood attached to the skin.

<Measurement method of thickness> Here, the thickness dimension D2 of the fabric 240 is in the state of the material, and is measured using [PEACOCK dial thickness gauge (Dial thickness gauge J-B) manufactured by Ozaki Manufacturing Co., Ltd. having a gauge of 50 mm in diameter. In addition, the thickness D1 of the surface sheet 211 is the thickness of the external appearance. As shown in FIG. 13, the surface sheet 211 is ideally cut along the mechanical direction of the fiber web 250, and cut using a digital microscope VHX-1000 manufactured by Keynes, etc. Take an enlarged photo of the surface and take a photo. Based on this enlarged photo, measure the maximum thickness of the surface sheet 211. Perform the same measurement at five randomly designated locations and calculate the average value. Use this average value as the thickness 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 252 is taken as the thickness dimension of the upper extension 253 of the fiber web 250 (from the upper surface 240b of the fabric 240 The separation size D3 of the apex 253a of the upward extending portion 253). In addition, the measurement operation is 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 bulkiness portions 254 having a small thickness dimension D3; and a plurality of high bulkiness portions 255 having a large thickness dimension D3. Since the lower extending portion 252 of the fiber web 250 has a concave-convex shape, the menstrual blood adhering to the skin can be effectively scraped together with the fabric 240 located below.

In addition, in the case where the surface sheet 211 is formed by the fluid entanglement method, in the lower extension portion 252 directly colliding with the fluid jetted by the high pressure, the portion of the web 250 where the fluid ejected from the nozzle directly collides with other parts , Its fluffiness is low. The low bulkiness portion 256 includes a portion where the fluid directly collides. In this case, the low bulkiness portion 256 has a higher fiber density than the high bulkiness portion 257. Therefore, the body fluid moving from the fabric 240 toward the downward extending portion 252 can move to the absorbent body located below more rapidly in the low bulkiness portion 256 having a higher fiber density than the high bulkiness portion 257.

The fibrous web 250 is integrated with the fabric 240 without entanglement but by entanglement. Therefore, it is more flexible than the case where it is joined to each other via an adhesive or the like. As the constituent fiber 251 of the fiber web 250 is entangled with the fabric 240, in addition to the part of the constituent fiber 251 being entangled or wound by the warp and weft yarns of the fabric 240, there may be a part of the constituent fiber 251 It is entangled so as to enter the warp yarn 242 formed by the twisted yarn and the original yarn of the weft yarn 243. In this manner, the constituent fibers 251 are entangled on the outer and inner surfaces of the warp yarns 242 and the weft yarns 243, so that the fiber web 250 can be stably integrated into the fabric 240.

The fiber 251 of the fiber web 250 has a fineness of 0.8 to 6.0 dtex, ideally 1.0 to 4.4 dtex, more preferably 1.3 to 3.3 dtex; a fiber length of 25 to 64 mm, ideally 32 to 58 mm, and more ideally 38 to 51 mm The staple fiber is composed of twisted yarn. The fineness of the constituent thread 241 is 10 to 100 cotton counts, preferably 20 to 60 cotton counts, and more preferably 30 to 45 cotton counts. 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 into the gap between the twisting of the original yarn with a larger denier or wind The tight winding around the constituent thread 241 enables the fiber web 250 to be entangled with the fabric 240 stably.

Again, as shown in FIG. 11, the fiber length of the short fibers of the web 250 is formed to be at least one of the separation size R1 of the warp yarns 242 adjacent to each other and parallel and the separation size R2 of the weft yarns 243 adjacent to each other. The separation size is larger. In this case, no short fibers fall out of the mesh 245 of the fabric 240, and by extending the short fibers across the mesh 245, the sheet strength and liquid diffusivity of the entire surface sheet 211 can be improved.

The content rate of the hydrophilic fiber of the fiber web 250 is less than 50% by mass, ideally 10 to 49% by mass, and the content rate of the hydrophobic fiber is more than 50% by mass, ideally 51 to 90% by mass. The proportion of hydrophobic fibers is higher than that of hydrophilic fibers. With a higher proportion of hydrophobic fibers, it can suppress diffusibility and can suppress the phenomenon of moisture regain.

In addition, when the content rate of the hydrophilic fiber is less than 10% by mass, the proportion of the hydrophobic fiber is relatively increased, and although the moisture regain phenomenon can be suppressed, the inhalability of menstrual blood drawn from the skin decreases. In addition, in the case where the content rate of the hydrophilic fiber is 50% by mass or more, although more menstrual blood is absorbed more quickly, the phenomenon of moisture regain is likely to occur. In the surface sheet 211, by containing hydrophilic fibers and hydrophobic fibers in a balanced manner, it is possible to achieve good liquid absorption, liquid diffusibility, and suppression of moisture regain.

<Twist Evaluation> First, as a sample A corresponding to the example, that is, a liquid-permeable sheet having a thickness of 0.57 mm and a mass of 47 g/m ² as the surface sheet 211 was cut into a length dimension of 100 mm×width dimension. 50 mm; and sample B corresponding to the comparative example, that is, a cotton sheet (thickness 100%) with a thickness of 0.33 mm and a mass of 31 g/m ² was cut into a length dimension of 100 mm×a width dimension of 15 mm. Next, using a Japanese academic rejuvenation type friction fastness testing machine, each sample was rubbed under predetermined measurement conditions (abrasion resistance 100 times, load 50g) to reproduce the state of friction between the surface sheet during wearing and the surface of the body .

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

According to the measurement results, the torque value corresponding to the sample A in the example without surface friction is 7.1, and the torque value under the surface friction is 6.8, which corresponds to 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. According to the presence or absence of surface friction, the surface sheet 211 of the embodiment does not cause a large change in torque value, and the friction with the body during use does not cause distortion. In addition, the surface sheet 211 has higher 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 as the comparative example is 55% or less compared to the surface sheet 211 of the embodiment is that in the case of the cotton sheet, when surface friction is applied, the entanglement of the cotton fiber is unwound and The reason is to reduce the strength of the sheet.

<Reverse evaluation> For the measurement of torsion evaluation, a sample C of a physiological sanitary napkin of an example and a sample D of a physiological sanitary napkin of a comparative example were prepared. Sample C and Sample D have the same structure except for the structure of the surface sheet. The surface sheet used in Sample C is the liquid-permeable sheet of Sample A used in the twist evaluation and the surface sheet used in Sample D Liquid-permeable sheet of sample B. First, prepare a doll that imitates the lower body of the human body, and let the doll wear the sanitary napkins of each sample C and D. Secondly, during the virtual walk, after the doll's thighs continued to move forward and backward for 5 minutes, 2 g of artificial menstrual blood was discharged from the opening corresponding to the doll's vaginal opening and dripped onto the surface of the sanitary napkin. Then, suppose to sit down and perform the action of exchanging the feet on the thighs of the doll. Set this behavior as a group and perform 5 times (5 groups), and then remove the sample from the doll. With respect to the samples C and D removed from the doll, the narrowest width dimension (mm) of the absorber which is in contact with the narrowest part near the crotch is measured with a measuring tool. This measurement was performed three times, and the average value was taken as the narrowest width dimension of the absorber of each sample.

In the measured structure, the narrowest width dimension of the absorber of sample C using the surface sheet 211 was 30 mm, and the narrowest width dimension of the absorber of sample D using the cotton sheet was 14 mm. In the surface sheet 211 used in 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 are not attached to each other, and twisting is unlikely to occur. In addition, in the cotton sheet used in Sample D, the width dimension of the absorber becomes small, and a large twist occurs. As the reason, it should be the entanglement of cotton fibers due to surface friction, the wrinkles formed during wearing, and the fibers after entanglement are attached to each other, forming a large groove extending longitudinally Therefore.

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

In an example of another embodiment of the present embodiment, as the raw material of the fabric 240, unbleached pulp fibers that have not been subjected to lignin removal treatment at all may be used. In this case, the unbleached pulp fiber containing a large amount of lignin component has a light brown color derived from the natural material itself. Therefore, the entire surface sheet 211 has a light brown natural hue. Since the surface sheet 211 has a light brown color, it can give a wearer, etc., an impression of a skin-oriented, highly natural product using natural materials. In addition, compared with the case where a white sheet with bleaching treatment is used, the redness of menstrual blood absorbed by the absorber 220 can be suppressed, and therefore, it is possible to alleviate the minor men who have just come to menstruation from having direct recognition of menstrual blood. Anxiety. Furthermore, 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, it is possible to give a skin-friendly impression with a natural hue together with the surface sheet 211 containing unbleached pulp fibers, and it can contribute to the concealment and antibacterial properties of menstrual blood.

In this specification, as the liquid-permeable sheet for the absorbent article 210 of the second invention, the embodiment of the surface sheet 211 disposed on the skin-facing side of the absorber 220 has been described, but it can also be used as the 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, or the like. In addition, the absorbent article 210 is not limited to sanitary napkins, and may include, for example, paper diapers for adults and children, and urine absorption pads, and may also be used as a liquid-permeable sheet through which urine and soft stool can pass.

The disclosure of the second invention described above can be organized into at least the following matters. A liquid-permeable sheet for absorbent articles, comprising: a fabric having a first surface and a second surface facing each other in the thickness direction; and a fibrous web, which is interlaced with the first fabric In a fiber web integrated with a surface, the constituent yarns of the woven fabric are formed by continuous twisted yarns composed of cellulose fibers, and the fiber mesh includes hydrophilic fibers and hydrophobic fibers.

The liquid-permeable sheet for absorbent articles disclosed in the second invention includes the following embodiments. (1) The constituent yarn system of the twisted yarn of the woven fabric includes: a plurality of warp yarns continuously extending; and a plurality of weft yarns continuously extending so as to intersect the warp yarns in the thickness direction. (2) The content rate of the hydrophobic fiber is higher than the content rate of the hydrophilic fiber. (3) The content rate of the hydrophobic fiber is 51 to 90% by mass, and the content rate of the hydrophilic fiber is 10 to 49% by mass. (4) The aforementioned hydrophilic fiber is irregular in cross-section and has a plurality of grooves extending in the extending direction. (5) The fiber web and the fabric are entangled by water flow to integrate the entanglement. (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, and the constituent threads of the woven fabric are composed of twisted yarns formed from a plurality of raw yarns The fineness of the twisted yarn is 10 to 100 counts of cotton yarn. (7) The absorbent article further includes an absorber, and is disposed on the skin-facing side of the absorber. (8) The fiber length of the short fibers is larger than at least one of the separation size of the warp yarns adjacent to each other and parallel, and the separation size of the weft yarns adjacent to each other parallel.

10: Absorbent articles (physiological sanitary napkins) 11: Liquid-permeable sheet (surface sheet) 20: Absorber 40: fabric 40a: 1st surface (lower surface) 40b: 2nd surface (upper surface) 41: Composition line 45: Mesh 50: Fiber web 51: constituent fibers 53: The part of the web that extends from the second side of the fabric 60: Hydrophilic fiber 61: Groove D2: Thickness of fabric D3: The thickness dimension of the part extending from the second surface in the fiber web Z: thickness direction 210: Absorbent articles (physiological sanitary napkins) 211: Liquid-permeable sheet (surface sheet) 220: absorber 240: fabric 240a: 1st surface (lower surface) 240b: 2nd surface (upper surface) 241: Composition line 245: Mesh 250: fiber web 251: constituent fibers 260: Hydrophilic fiber 261: Groove R1: Separation size of adjacent and parallel warp yarns R2: Separated size of adjacent and parallel weft yarns Z: thickness direction

The drawing shows specific embodiments of the first and second inventions, including not only the indispensable structures of the invention but also optional and ideal embodiments. 1 is a plan view of a sanitary napkin as an example of the absorbent article of the first invention viewed from the front side. Fig. 2 is a plan view of a 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 partially enlarged view of a liquid-permeable sheet (surface sheet). Fig. 5 is a diagram showing a state where the liquid-permeable sheet is separated into a fiber web and a fabric. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 4. 7 is an enlarged view of hydrophilic fibers as an example of hydrophilic fibers. 8 is a plan view of a sanitary napkin as an example of the absorbent article of the second invention viewed from the front side. 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 where the liquid-permeable sheet is separated into a web and a fabric. Fig. 13 is a cross-sectional view taken along line XIII-XIII of Fig. 11. 14 is an enlarged view of hydrophilic fibers as an example of hydrophilic fibers.

11: Liquid-permeable sheet (surface sheet)

11a: The opposite side of the skin (top)

11b: Non-skin facing side (below)

12: back sheet

14: side sheet

20: Absorber

20c: 1st side edge

20d: 2nd side edge

21: Liquid-absorbing core material

22: core material cover sheet

22a, 22b: side edge

23: Overlap

25: The first covered part

26: The second covered part

31: Central area

40: fabric

40a: 1st surface (lower surface)

40b: 2nd surface (upper surface)

45: Mesh

50: Fiber web

Claims (12)

A liquid-permeable sheet for absorbent articles, characterized by comprising: a woven fabric having a first surface and a second surface facing in a thickness direction; and a fiber web, which is entangled with the first fabric of the woven fabric Face integration, The constituent threads of the aforementioned fabric are formed of cellulose fibers, The constituent fibers of the fiber web are substantially the same as the second surface of the woven fabric, or extend more outward than the thickness direction of the woven fabric. A liquid-permeable sheet for absorbent articles, characterized by comprising: a woven fabric having a first surface and a second surface facing in a thickness direction; and a fiber web, which is entangled with the first fabric of the woven fabric Face integration, The constituent yarns of the aforementioned fabric are formed by continuous twisted yarns composed of cellulose fibers, The fiber web system includes hydrophilic fibers and hydrophobic fibers. The liquid-permeable sheet for absorbent articles as claimed in item 1 of the patent scope, wherein the constituent fibers of the fiber web include hydrophilic fibers and hydrophobic fibers. The liquid-permeable sheet for absorbent articles as claimed in item 1 of the patent scope, wherein the thickness dimension of the fabric, the thickness dimension of the portion of the fiber web extending from the second surface of the fabric is 1.1 to 4.0 times . A liquid-permeable sheet for absorbent articles as claimed in item 1, 3 or 4 of the patent application, wherein a part of the constituent fibers of the fiber web is wound around the constituent threads of the fabric and passes through a plurality of meshes of the fabric It extends toward the second surface side. The liquid-permeable sheet for absorbent articles as claimed in item 2 of the patent scope, wherein the constituent thread system composed of the twisted yarn of the fabric includes: a plurality of warp yarns extending continuously; and A plurality of weft yarns extending continuously in a manner crossing each other in the thickness direction. For example, in the liquid-permeable sheet for absorbent articles according to claim 2 or 3, the content rate of the hydrophobic fiber is higher than the content rate of the hydrophilic fiber. The liquid-permeable sheet for absorbent articles as claimed in item 2, 3 or 7 of the patent application, wherein the hydrophilic fibers are profiled in cross section and have a plurality of grooves extending in the extending direction. The liquid-permeable sheet for absorbent articles according to any one of claims 1 to 8, wherein the fiber web and the fabric are entangled and integrated by fluid entanglement treatment. The liquid-permeable sheet for absorbent articles as claimed in item 6 of the patent application, wherein 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 aforementioned constituent thread is composed of a twisted yarn formed from a plurality of raw yarns, and the fineness of the twisted yarn is 10 to 100 counts of cotton yarn. The liquid-permeable sheet for absorbent articles according to any one of claims 1 to 10, wherein the absorbent article further includes an absorber and is arranged on the skin-facing side of the absorber. A liquid-permeable sheet for absorbent articles as claimed in item 10 of the patent application, wherein the fiber length of the short fibers is a separation size of the warp yarns adjacent to each other and parallel to the fabric, and the weft yarns adjacent to each other At least one of the separation sizes is larger.

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