JP7337494B2 - Liquid-permeable sheet for absorbent articles - Google Patents

Description

The present invention relates to a liquid-permeable sheet for absorbent articles.

Liquid-permeable surface sheets for absorbent articles such as sanitary napkins and disposable diapers are required to smoothly transfer excretions such as menstrual blood and urine to the absorbent body, and to prevent liquid once absorbed by the absorbent body from returning. (Rewet) is required to be prevented.

As a sheet with excellent liquid absorbency, for example, Patent Document 1 discloses a low-density woven fabric having sufficient strength and excellent shape stability by interlacing a coarse woven fabric and a nonwoven fabric. In addition, the low-density woven fabric of Patent Document 1 has a soft texture, is easy to handle, and has excellent liquid absorbency due to the fiber material that constitutes the woven fabric.

However, although such a composite sheet in which a woven fabric and a nonwoven fabric are entangled has excellent liquid permeability, when a certain amount of liquid permeates the sheet, it becomes difficult for the liquid to be drawn into the sheet, resulting in smooth absorption. There is a possibility that it will be diffused on the sheet surface without being transferred to the body. If the liquid spreads on the surface of the sheet, the user may feel sticky, and the feeling of use may deteriorate. In addition, due to the excellent liquid absorbency of the sheet, the sheet tends to draw in the liquid when the liquid is about to return due to body pressure or the like, which may cause the liquid to return to the surface of the sheet.

JP-A-11-170413

The present invention has been made in view of the conventional problems as described above, and its object is to reduce the diffusion of liquid when the fabric absorbs the liquid, and to prevent the liquid from being absorbed and held by the fabric or the absorbent body. Another object of the present invention is to provide a liquid-permeable sheet for an absorbent article that suppresses the backflow of liquid.

The main invention for achieving the above object is
a fabric having hydrophobic properties;
a non-woven fiber assembly comprising hydrophilic fibers, wherein some of the fibers are entangled with said fabric;
A liquid-permeable sheet for absorbent articles having
The fiber assembly includes a skin-side extending portion provided closer to the skin than the fabric and a non-skin-side extending portion provided closer to the non-skin side than the fabric, and the non-skin-side extending portion is provided. The maximum thickness of the portion is greater than the maximum thickness of the skin-side extending portion
A liquid-permeable sheet for absorbent articles characterized by:
Other features of the present invention will become apparent from the description of the specification and accompanying drawings.

According to the present invention, while maintaining the texture of the fabric material, the liquid is not retained in the fabric due to the hydrophobicity of the fabric, but is drawn into the fiber assembly intertwined with the fabric, and further flows through the fiber assembly. It is quickly transferred to the underlying absorbent. This suppresses the diffusion of the liquid on the fabric surface. In addition, even if body pressure is applied during wearing and the liquid tries to return, the fabric is hydrophobic, so it is difficult for the liquid to be drawn in, and the liquid return (rewet) can be suppressed. A liquid sheet can be provided.

FIG. 1 is a plan view of the sanitary napkin 1 viewed from the skin side. FIG. 2 is a plan view of the sanitary napkin 1 viewed from the non-skin side. FIG. 3 is a cross-sectional view along line XX of FIG. FIG. 4 is a partially enlarged view of the surface sheet 3. FIG. FIG. 5 is a diagram showing a state in which the surface sheet 3 is separated into a woven fabric 40 and a fiber assembly 50. As shown in FIG. FIG. 6 is an enlarged view of a portion including C1 to C4 of the twisted yarn shown in FIG. 5 is a cross-sectional view along line YY in FIG. 4; FIG. 4 is an enlarged view of fibers 60 in an example of fibers 51 of the fiber assembly 50. FIG.

At least the following matters will become apparent from the descriptions of this specification and the accompanying drawings.
Liquid permeability for absorbent articles comprising a hydrophobic woven fabric and a non-woven fiber assembly comprising hydrophilic fibers, some of the fibers being entangled with the woven fabric is a sheet.

According to such a liquid-permeable sheet for absorbent articles, the hydrophobicity of the woven fabric makes it difficult for liquid to be drawn in, and the liquid is guided between the constituent threads of the woven fabric. Since the fiber assembly intertwined with the woven fabric has hydrophilic fibers, the liquid is drawn in and retained, the liquid is more easily guided to the lower layer, and the diffusion of the liquid on the woven fabric surface is suppressed. In addition, even if body pressure is applied during wearing and the liquid tends to return, the fabric closest to the skin is hydrophobic, so it is difficult for the liquid to be drawn in, and liquid return (rewet) can be suppressed.

The liquid-permeable sheet for such an absorbent article has a thickness direction, the fiber assembly is arranged on the non-skin side of the woven fabric in the thickness direction, and the hydrophilicity of the fiber assembly is increased. The degree of hydrophilicity is preferably higher than the hydrophilicity of the fabric.

According to such a liquid-permeable sheet for absorbent articles, the fiber assembly having a hydrophilicity higher than that of the fabric is arranged on the non-skin side of the fabric, so that the liquid has a hydrophilicity It is possible to suppress the diffusion of the liquid on the surface of the woven fabric.

This liquid-permeable sheet for absorbent articles has a thickness direction, and the constituent yarns of the fabric are a plurality of continuously extending warp yarns, and the warp yarns and the warp yarns intersect each other in the thickness direction. The fiber length of the longest fiber in the fiber assembly is equal to the maximum distance between adjacent warps and the maximum distance between adjacent wefts of the woven fabric. and the fiber length of the shortest fiber in the fiber assembly is the maximum distance between adjacent warp yarns and the maximum distance between adjacent weft yarns of the fabric. is preferably longer than the maximum separation distance of at least one of

According to such a liquid-permeable sheet for absorbent articles, the fiber length of the fibers of the fiber assembly is longer than the maximum separation distance between adjacent warps or wefts of the fabric, so that the fibers of the fiber assembly are The fibers of the fiber assembly can be well entwined with the constituent yarns of the fabric, and the fibers of the fiber assembly can extend toward the absorbent body. By doing so, the liquid in contact with the fabric can be easily guided to the absorbent body through the entangled fibers of the fiber assembly, and diffusion of the liquid can be suppressed.

In such a liquid-permeable sheet for absorbent articles, the fiber assembly includes a skin-side extending portion provided on the skin side of the fabric and a non-skin-side extending portion provided on the non-skin side of the fabric. The maximum thickness of the non-skin-side extending portion is preferably larger than the maximum thickness of the skin-side extending portion.

According to such a liquid-permeable sheet for absorbent articles, since the maximum thickness of the non-skin-side extending portion of the fiber assembly is larger, more liquid can flow through the fibers of the fiber assembly. It becomes easy to enter the absorber arranged below the fiber assembly.

In such a liquid-permeable sheet for absorbent articles, the fiber assembly contains hydrophobic fibers, and in the fiber assembly, the weight of the hydrophobic fibers contained per unit volume is contained per unit volume. desirably greater than the weight of said hydrophilic fibers.

According to such a liquid-permeable sheet for absorbent articles, the fiber assembly contains hydrophobic fibers, so that the fiber assembly becomes difficult to retain liquid, and the liquid is absorbed along the fibers of the fiber assembly. It will be guided to the side of the body. In addition, even if the liquid tries to return due to body pressure during wearing, since the weight of the hydrophobic fiber contained per unit volume is larger in the fiber assembly, it is difficult to draw in the liquid that tried to return, and the liquid does not return. Suppress.

In such a liquid-permeable sheet for an absorbent article, it is desirable that the average thickness of the twisted yarns of the fabric is larger than the average thickness of the fibers of the fiber assembly.

According to such a liquid-permeable sheet for absorbent articles, since the twisted yarns of the fabric are thick, the lattice-like skeletal structure formed by the twisted yarns of the fabric is stable and does not easily collapse even when body pressure is applied. Since the space (distance) to the body can be secured, the return of the liquid to the fabric can be suppressed.

In such a liquid-permeable sheet for absorbent articles, it is desirable that the hydrophilic fibers included in the fiber assembly have a plurality of grooves along the extending direction.

According to such a liquid-permeable sheet for an absorbent article, since the fibers of the fiber aggregate have a plurality of grooves, the outer peripheral surface of the fibers is in contact with the liquid compared to the case where the outer peripheral surface is flat. Since the surface area is increased and the capillary force of the grooves facilitates the flow of the liquid, the ability of the fiber assembly to draw the liquid is improved.

In such a liquid-permeable sheet for absorbent articles, it is desirable that the fiber assembly exists within a space surrounded by the constituent yarns of the fabric.

According to such a liquid-permeable sheet for an absorbent article, since the fiber assembly exists in the space surrounded by the constituent yarns of the fabric, the liquid induced between the constituent yarns passes through the fiber assembly. Since the liquid is easily drawn in and the liquid is further guided toward the absorbent body along the fiber assembly, the ability to draw in the liquid can be improved.

In such a liquid-permeable sheet for an absorbent article, it is preferable that, in a plan view of the space, a region where the fibers of the fiber assembly exist is smaller than a region where the fibers of the fiber assembly do not exist.

According to such a liquid-permeable sheet for absorbent articles, in the space surrounded by the constituent yarns of the fabric, the region in which the fibers of the fiber assembly do not exist is larger, so that gaps can be secured in the space. and the air permeability between the fiber assembly can be maintained.

Further, an absorbent article comprising the liquid-permeable sheet described above, an absorbent core that absorbs liquid, and a sheet portion provided between the liquid-permeable sheet and the absorbent core, In the absorbent article, the hydrophilicity of the sheet portion is higher than the hydrophilicity of the fiber assembly contained in the liquid-permeable sheet.

According to such an absorbent article, since the hydrophilicity of the sheet portion covering the absorbent core is higher than the hydrophilicity of the fiber assembly, the absorbent core is arranged on the non-skin side of the fiber assembly. This makes it easier for the liquid to be drawn into the liquid-permeable sheet, thereby suppressing the liquid from diffusing into the liquid-permeable sheet.

===Embodiment===

Hereinafter, as an absorbent article of the present invention, an embodiment will be described by taking a sanitary napkin as an example. However, the present invention is not limited to this, and can be applied to other absorbent articles such as pantyhose sheets and incontinence pads.

FIG. 1 is a plan view of a sanitary napkin 1 (hereinafter also referred to as "napkin 1") viewed from the skin side. FIG. 2 is a plan view of the sanitary napkin 1 viewed from the non-skin side. FIG. 3 is a cross-sectional view along line XX of FIG.

The napkin 1 has a front-rear direction, a width direction, and a thickness direction which are orthogonal to each other. In the front-rear direction, the side that contacts the lower abdomen of the wearer is called the front side, and the side that contacts the buttocks of the wearer is called the rear side. Thickness direction WHEREIN: The side which touches a wearer is called a skin side, and the other side is called a non-skin side.

As shown in FIG. 3, in the napkin 1, a pair of side sheets 5, a top sheet (liquid-permeable sheet) 3, an absorbent body 2, and a back sheet 4 are laminated in order from the skin side in the thickness direction. ing. The surface sheet 3 and the absorbent body 2 are joined together by a known joining means such as a hot-melt adhesive. The surface sheet 3 and the back sheet 4 are larger in planar size than the absorbent body 2 and cover the entire planar surface of the absorbent body 2 . The top sheet 3, the back sheet 4 and the side sheets 5, which are laminated to each other, are joined together via an outer peripheral seal portion 8 positioned along the outer peripheral edge of the napkin 1. As shown in FIG.

As shown in FIG. 1, the pair of side sheets 5 are provided on both sides in the width direction, and are arranged on the skin side of the topsheet 3 along the front-rear direction. A pair of side sheets 5 are joined to the top sheet 3 via side joints (not shown) formed by known adhesive means or welding means. The side joint portion for fixing the side seat 5 may be a seal line along the front-rear direction having a design element such as a floral pattern or a geometric pattern.

Moreover, the napkin 1 has a pair of wing portions 6 extending from the central region in the front-rear direction of the napkin 1 to both lateral sides. The wing portions 6 are formed by the side sheets 5 extending outward from both sides of the top sheet 3 in the width direction, and the back sheet 4 . In addition, the napkin 1 may be in a form that does not have the wing portion 6 .

Although not shown, in order to improve the flexibility of the napkin 1, an intermediate sheet formed of nonwoven fabric or the like having a relatively high fiber density is placed between the surface sheet (liquid-permeable sheet) 3 and the absorbent body 2. may be placed. In addition, in order to suppress the leakage of bodily fluids, a leak-proof sheet made of a liquid-impermeable plastic film or non-woven fabric, which preferably has air permeability, may be arranged between the absorbent body 2 and the back sheet 4. good.

As shown in FIG. 2, the non-skin side of the napkin 1 (the non-skin side of the back sheet 4) is provided with an adhesive area 11, which is coated with an adhesive or the like. When the napkin 1 is used, the adhesive area 11 is attached to the skin side of underwear or the like, thereby fixing the napkin 1 to the underwear or the like. In FIG. 2, six rectangular adhesive regions 11 having long sides in the front-rear direction are arranged at intervals in the width direction, but the shape and number of the adhesive regions 11 are not limited to this.

Similarly, the non-skin side of each wing 6 (the non-skin side of the back sheet 4) is provided with a wing adhesive region 12. As shown in FIG. When the napkin 1 is used, the wing adhesive regions 12 are attached to the non-skin side of underwear or the like, thereby fixing the napkin 1 to the underwear or the like. In FIG. 2, each wing portion 6 is provided with one rectangular wing adhesive region 12 having a long side in the front-rear direction, but the shape and number of the wing adhesive regions 12 are not limited to this. The adhesive area 11 and the wing adhesive area 12 are each covered with a plastic film separator (not shown).

Further, in the napkin 1, at least one of the absorbent body 2 and the topsheet 3 has a compressed recess 7 (recess) recessed in the thickness direction. In this embodiment, the topsheet 3 and the absorbent body 2 are compressed in the thickness direction from the skin side of the topsheet 3, and the topsheet 3 and the absorbent body 2 are joined and integrated. The compressed recesses 7 prevent the surface sheet 3 from floating, and when menstrual blood or the like flows into the compressed recesses 7, it is possible to promote permeation into the absorbent body 2 and suppress diffusion.

The surface sheet 3 is liquid-permeable, has a skin side (upper surface) 3a and a non-skin side (lower surface) 3b located on the opposite side in the thickness direction, and is composed of a fabric 40 and a fiber assembly 50. be done. The back sheet 4 can be formed from a liquid-impermeable and moisture-permeable plastic film, a liquid-impermeable nonwoven fabric, a laminate sheet thereof, or the like. A known non-woven fabric can be used for the side sheets 5, but a hydrophobic or water-repellent sheet material is preferably used in order to effectively prevent lateral leakage of bodily fluids.

The absorbent body 2 is a member that absorbs and retains excretions such as menstrual blood, and as shown in FIG. It has a liquid-permeable core wrap sheet 20 that wraps the entire absorbent core 10 to improve diffusibility. The core wrap sheet 20 includes a sheet portion 21 (a portion of the core wrap sheet 20) located on the non-skin side of the topsheet 3. As shown in FIG.

The absorbent core 10 is formed into a predetermined shape by adding a superabsorbent polymer (so-called SAP) or the like, which is liquid-absorbing granules, to pulp fibers, cellulose-based absorbent fibers, or the like, which are liquid-absorbing fibers. It is. The core wrap sheet 20 is a liquid-permeable sheet, and examples thereof include tissue paper and airlaid.

The core wrap sheet 20 is arranged so as to cover the entire absorbent core 10, and the side edge portions 20a and 20b of the core wrap sheet 20 along the front-rear direction are located at the central portion of the absorbent core 10 in the width direction. They are laminated together on the non-skin side. In the present embodiment, the core wrap sheet 20 is formed of one continuous sheet, and includes a sheet portion covering the skin side surface of the absorbent core 10 and a sheet separate from the sheet portion covering the non-skin side surface. It may be configured to be divided into parts.

FIG. 4 is a partially enlarged view of the topsheet 3 as viewed from the skin side, and FIG. 5 is a diagram showing the state in which the topsheet 3 is separated into a woven fabric 40 and a fiber aggregate 50 . As shown in FIGS. 3, 4 and 5, the topsheet 3 includes a fabric 40 located on the skin side and a fiber assembly 50 located on the non-skin side. As shown in FIG. 3 and FIG. 5, the woven fabric 40 has a lower surface 40a facing the fiber assembly 50 and an upper surface 40b which is the opposite surface that comes into contact with the skin. The woven fabric 40 and the fiber assembly 50 are integrated by being entangled (entangled) with each other. A method for interlacing the fabric 40 and the fiber assembly will be described later.

As shown in FIG. 4, the woven fabric 40 is composed of constituent yarns 41 woven in a grid pattern. The constituent yarns 41 have a plurality of warp yarns 42 and a plurality of weft yarns 43 that intersect the warp yarns 42, and intersect each other in the thickness direction to form a plurality of textures 45. As shown in FIG. The constituent yarns 41 of the fabric 40 are twisted yarns formed by twisting raw yarns made of cotton yarns (cotton fibers). In addition to cotton fibers, cellulose fibers such as natural cellulose fibers such as hemp and pulp fibers, regenerated cellulose fibers such as rayon, and semi-synthetic cellulose fibers such as acetate are preferably used as materials for the raw yarn. As for the cotton yarn used as the raw yarn, those with a thickness of 10 to 100 cotton count are preferable. Since the fabric 40 mainly made of cotton material or the like is positioned on the skin side of the topsheet 3 in this manner, the user can obtain a comfortable touch and skin troubles are less likely to occur. Further, the weaving method of the woven fabric 40 is not limited to the plain weave woven in a lattice pattern as described above, and any known weaving method such as twill weave, satin weave, or leno weave can be appropriately employed.

As described above, when the raw yarn of the woven fabric 40 is composed of cotton yarn or the like, the woven fabric itself has excellent liquid absorption, but the liquid does not smoothly transfer to the absorbent body due to the liquid absorption. There is a risk that the liquid will spread on the surface of the sheet made of this material, giving the wearer a sticky feeling. In contrast, in the present embodiment, the fabric 40 is coated with a water repellent agent. One example of the method of applying the water repellent is dipping in an aqueous treatment bath containing 0.1% paraffin water repellent. By applying the water-repellent finish to the fabric 40 in this manner, the fabric 40 is imparted with hydrophobicity. The water repellent is not limited to paraffin-based agents, and may be selected from among known water-repellent agents such as fluorine-based agents and silicon-based agents, which are less irritating to the skin.

Here, "hydrophobic" means that liquid does not spread on the surface of the fabric 40 and the surface of the fabric 40 has a contact angle greater than 90°. The contact angle is a state in which the fabric 40 having a horizontal surface (horizontal surface) is in contact with water (droplets) dropped on the horizontal surface, and the contour curve at the intersection of the liquid contour curve and the horizontal surface. is the angle formed by the tangent line of and the horizontal plane. The fabric 40 coated with water repellent has a contact angle greater than 90° and has a hydrophobic surface.

The fiber assembly 50 is formed by a known manufacturing method such as a spunbond method using long fibers or a dry method in which short fibers are carded in a certain direction by a carding machine and the fibers are arranged to form a web. It is a fiber assembly at a stage before it is processed into a nonwoven fabric. Moreover, the fiber assembly 50 is formed from constituent fibers 51 containing hydrophilic fibers. Examples of hydrophilic fibers include regenerated cellulose fibers such as rayon and fibril rayon, natural cellulose fibers such as cotton and pulverized pulp, and semi-synthetic cellulose such as acetate.

As a method for entangling and integrating the woven fabric 40 and the fiber assembly 50, for example, a known hydroentangling method can be used. In the manufacturing process of the liquid-permeable sheet by the hydroentanglement method, a continuous laminate formed by laminating an aggregate of continuous fibers, which is the material of the fiber aggregate 50, on the upper surface of a continuous grid-like fabric, which is the material of the fabric 40. , high-pressure water jets are jetted from a plurality of nozzles spaced apart in a direction intersecting the conveying direction of the continuous laminate. Thereby, the constituent fibers 51 of the fiber assembly 50 and the constituent yarns 41 of the fabric 40 can be entangled and integrated. A pattern can also be imparted to the integrated sheet by the pressure of water.

When applying hydroentanglement, the above-mentioned continuous laminate in which the continuous fabric and the continuous fiber assembly are laminated is conveyed by a conveying means consisting of a metal mesh belt, and a nozzle sprays a high-pressure water jet onto the upper surface of the continuous laminate. At this time, the fibers of the fiber assembly and the constituent yarns of the fabric are entangled on the upper surface side, and are also entangled on the lower surface side facing the conveying means by the water flow that bounces off the conveying means. Further, according to the hydroentanglement method, by appropriately changing the structure of the mesh belt of the conveying means, it is possible to obtain the surface sheet 3 having desired sheet properties in terms of thickness, mass, absorption rate, sheet strength, etc. .

As described above, by arranging the surface sheet 3 in which the fabric 40 having hydrophobicity and the fiber assembly 50 having hydrophilic fibers are entangled on the skin side of the napkin 1, the hydrophobic property of the fabric 40 The surface of the woven fabric 40 becomes less likely to attract liquid, and the liquid is guided between the constituent yarns 41 of the woven fabric 40 (that is, the texture 45). Since the fiber assembly 50 intertwined with the woven fabric 40 has hydrophilicity, each constituent fiber 51 draws and holds the liquid introduced between the constituent yarns 41 . Further, since the constituent fibers 51 extend toward the absorbent body 2, the liquid is easily guided to the absorbent body 2 located in the lower layer along the constituent fibers 51. As shown in FIG. As a result, it is possible to suppress diffusion of the liquid on the surface of the fabric 40 . In addition, even if body pressure is applied while the napkin 1 is worn and the liquid tries to return, the fabric 40 closest to the skin has hydrophobicity so that it is difficult for the liquid to be drawn in and liquid return (rewet) is prevented. can be done.

Moreover, although the fiber assembly 50 contains hydrophilic fibers as described above, it may contain not only hydrophilic fibers but also hydrophobic fibers. As the hydrophobic fibers, polyester thermoplastic resin fibers containing polyethylene terephthalate (PET) are suitable. Composite fibers such as conjugate fibers having a core-sheath structure and side-by-side type conjugate fibers can also be used.

In addition, when the fiber assembly 50 contains hydrophobic fibers, the blending ratio of the hydrophilic fibers and the hydrophobic fibers is such that the weight of the hydrophobic fibers contained per unit volume is equal to the weight of the hydrophilic fibers contained per unit volume. is preferably greater than As an example, it is preferable to mix 70% by weight of hydrophobic fibers and 30% by weight of hydrophilic fibers. Since the fiber assembly 50 contains hydrophobic fibers, the fiber assembly 50 itself is less likely to retain liquid, and the liquid is more likely to be guided to the absorbent body 2 side along the constituent fibers 51 of the fiber assembly 50 . In addition, even if the liquid tries to return due to the body pressure while wearing the napkin 1, the weight of the hydrophobic fiber contained per unit volume is larger as the composition ratio of the fibers of the fiber assembly 50, so it tried to return. It is difficult to draw in liquid and suppresses liquid return.

Further, as an example, the hydrophilic fibers contained in the fiber assembly 50 are modified to be hydrophilic by coating the surfaces of the PET fibers with a surfactant to reduce the contact angle of the PET fiber surfaces. may be used. In this case, preferred surfactants to be used include nonionic surfactants such as hydrophilic silicone oils, anionic surfactants, cationic surfactants, and amphoteric surfactants.

In addition, the fiber assembly 50 is arranged on the non-skin side of the fabric 40 in the thickness direction. And it is desirable that the liquid absorbency of the sheet portion 21 covering the absorbent core 10 arranged on the non-skin side thereof is higher than the liquid absorbency of the fabric 40 .

<Hydrophilicity evaluation>
In this respect, the degree of hydrophilicity of the woven fabric 40, the fiber assembly 50 and the sheet portion 21 was evaluated by a sedimentation test. The materials and test procedures used for evaluation are described below.

(Evaluation materials)
A: Gauze that is unbleached and dipped in advance with a fluorine-based water repellent agent at a concentration of 0.1% B: Rayon fiber and polyethylene terephthalate (PET) fiber (70W manufactured by Toyobo Co., Ltd.), Rayon fiber: PET fiber = Fiber assembly mixed at a mass ratio of 70:30 C: Unbleached tissue paper D: Airlaid pulp (without synthetic fiber, with synthetic fiber)
(Measuring method)
(1) Collect 5 g of each material A to D and prepare a test piece (2) Cylindrical basket (copper wire diameter 0.4 mm (No. 26 wire), diameter 50 mm, depth 80 mm, distance between wires 20 mm, total weight 3 g)) (3) Fill the beaker with water to a depth of about 200 mm (4) Place the cylindrical basket on its side and gently drop it from a height of 10 mm above the water surface (5) Cylinder Measure the time from when the mold basket touches the water surface until it sinks under the water surface (if the basket is tilted, the end point is when the rear end sinks under the water surface).

At the time of measurement, change the water each time and wipe off the moisture in the basket each time. When each material A to D was dropped into water by the above method and the sinking speed (settling speed (seconds)) was measured, the gauze of A was 180 seconds, the fiber assembly of B was 4.5 seconds, and the sheet part 21 C, which is an example, took 3.3 seconds, and D, which is another example of the sheet portion 21, took 1.6 seconds without synthetic fibers and 2.7 seconds with synthetic fibers. From this, it was confirmed that C or D, which is used as the material of the sheet portion 21, has a high degree of hydrophilicity, and that the next highest degree of hydrophilicity is the fiber assembly.

In the present embodiment, by arranging the fiber assembly 50 having a hydrophilicity higher than the hydrophilicity of the fabric 40 on the non-skin side of the fabric 40, the liquid is quickly drawn into the fiber assembly 50 having a high hydrophilicity. will be Thereby, it is possible to suppress the diffusion of the liquid on the surface of the fabric 40 .

In addition, since the hydrophilicity of the sheet portion 21 located on the skin side of the absorbent core 10 is higher than the hydrophilicity of the fiber assembly 50, the liquid is absorbed by the sheet portion provided on the non-skin side of the fiber assembly 50. It becomes easy to be drawn into 21 and further guided to the absorbent core 10 . Diffusion of the liquid can be suppressed by smoothly transferring the liquid to the absorbent core 10 .

Since the fiber assembly 50 is integrated with the fabric 40 by entangling without an adhesive or the like, the fiber assembly 50 is superior in flexibility compared to the case where the fibers are joined to each other with an adhesive or the like. In addition, as shown in FIG. 4, some of the constituent fibers 51 are entangled with the warp yarns 42 and the weft yarns 43 of the fabric 40, or are wound so as to cling. However, in some cases, the warp yarn 42 and the weft yarn 43, which are twisted yarns, are entangled so as to enter between the raw yarns. Thereby, the fiber assembly 50 and the fabric 40 are stably integrated.

The constituent fibers 51 of the fiber assembly 50 are short fibers having a fiber length of 25 to 64 mm, preferably 32 to 58 mm, more preferably 38 to 51 mm. The length relationship between the constituent fibers 51 having each fiber length and the constituent yarns 41 of the woven fabric 40 will be described with reference to FIGS. 4 and 6. FIG. First, in one texture 45 among the textures 45 of the fabric 40 shown in FIG. FIG. 6 is an enlarged view of a portion including C1 to C4 of the texture 45 shown in FIG. In FIG. 6, in order to measure the distance between the adjacent warp yarns 42, first, the intersections C1 and C4 and the intersections C2 and C3 are connected by straight lines, and the C1-C4 line and the C2-C3 line are each divided into 10 equal parts. do. Then, among the 10 equally divided points on the lines C1-C4 and C2-C3, the points facing each other in the width direction are connected by straight lines (broken lines) S1 to S9 in order from the front in the front-rear direction. If the widthwise inner ends of the adjacent warp yarns 42 are located outside the widthwise outer ends of the C1-C4 line or the C2-C3 line, each of the lines S1 to S9 is positioned at the widthwise inner end of the warp yarns 42. Extend until it touches the The distances between the intersections of the lines S1 to S9 and the widthwise inner ends of the adjacent warp yarns 42 are indicated by L1 ₁ to L1 ₉ , and the lengths of L1 ₁ to L1 ₉ are measured. For example, in L1 ₅ , the inner ends in the width direction of the adjacent warp yarns 42 are positioned outside in the width direction with respect to the C1-C4 line and the C2-C3 line, respectively, and the distance between the warp yarns 42 is compared. is getting longer. On the other hand, in L1 ₉ , the inner ends in the width direction of the adjacent warp yarns 42 are positioned inside in the width direction with respect to the lines C1-C4 and C2-C3, and the distance between the warp yarns 42 is relatively It's getting shorter.

Such measurement is performed by selecting four adjacent weaves 45, and the length of the longest L1 among them is taken as the maximum distance L1 between adjacent warps 42 (see FIG. 4). Then, by the same method, the points of intersection C1 and C2 and the points of intersection C3 and C4 in FIG. or a line extending the line and the inner ends of the adjacent wefts 43 in the front-rear direction. It is possible. The length of the longest L2 thus measured is taken as the maximum separation distance L2 (see FIG. 4) between the weft yarns 43 adjacent to each other. When compared with the fiber lengths of the constituent fibers 51 of the fiber assembly 50, the longest fiber length among the constituent fibers 51 is the maximum distance L1 between the adjacent warp yarns 42 and the maximum distance L2 between the adjacent weft yarns 43. longer than the maximum separation distance of at least one of Similarly, even with the shortest fiber length among the constituent fibers 51, at least one of the maximum distance L1 between the adjacent warp yarns 42 and the maximum distance L2 between the adjacent weft yarns 43 is the maximum distance. is longer than

That is, the fiber length of the constituent fibers 51 of the fiber assembly 50 is longer than the maximum separation distance between the adjacent warp yarns 42 or weft yarns 43 of the fabric 40, so that the constituent fibers 51 of the fiber assembly 50 are the constituent yarns of the fabric 40. Since the fibers 51 of the fiber assembly 50 are well entangled with the fabric 41 and extend toward the absorbent body 2 side, the liquid in contact with the fabric 40 is drawn into the absorbent body 2 along the constituent fibers 51 of the entangled fiber assembly 50. It becomes easy to spread, and the diffusion of the liquid can be suppressed.

FIG. 7 is a cross-sectional view taken along the line YY in FIG. 4, showing the sheet portion 21 and the absorbent core 10 positioned on the non-skin side of the topsheet 3 in phantom lines. Referring to FIG. 7 , in the topsheet 3 , some constituent fibers 51 of the fiber assembly 50 extend toward the skin side or the non-skin side in the thickness direction from the woven fabric 40 . Specifically, the fiber assembly 50 includes a skin-side extending portion 52 provided closer to the skin than the upper surface 40b of the woven fabric 40 and a non-skin-side extending portion 52 provided closer to the non-skin side than the lower surface 40a of the woven fabric 40. and an exit portion 53 . The non-skin-side extending portion 53 is a portion directly injected with a high-pressure water stream when formed by the hydroentanglement method. On the other hand, the skin-side extending portion 52 penetrates between the lattice-like constituent yarns 41 of the fabric 40 and the constituent yarns 41 that were positioned below when the high-pressure water jet was jetted, to the mesh belt side as a conveying means. This is the extended part.

Further, as shown in FIG. 7, the maximum thickness D1 of the skin-side extending portion 52 is defined as the thickness from the upper surface 40b of the fabric 40 to the point 51a where the skin-side extending portion 52 extends most toward the skin side. Assuming that the maximum thickness D2 of the non-skin-side extending portion 53 is the thickness from the lower surface 40a to the point 51b where the non-skin-side extending portion 53 extends most toward the non-skin side, the maximum thickness of the non-skin-side extending portion 53 is Thickness D2 is preferably greater than maximum thickness D1 of skin-side extending portion 52 .

The maximum thickness D1 and the maximum thickness D2 are apparent thicknesses, and the thickness dimensions are measured by first cutting the surface sheet 3 preferably along the thickness direction of the fiber assembly 50, as shown in FIG. Then, an enlarged photograph of the cut surface is taken using a digital microscope VHX-1000 manufactured by Keyence Corporation or the like. Based on this enlarged photograph, the distance (D1) from the upper surface 40b of the woven fabric 40 to the point 51a of the skin-side extending portion 52 extending to the skin side most is measured. The distance (D2) to the point 51b of the extending portion 53 extending most toward the non-skin side is measured.

In this way, since the maximum thickness D2 of the non-skin-side extending portion 53 of the fiber assembly 50 is larger, more liquid is drawn to the non-skin side along the fibers 51 of the fiber assembly 50, The liquid can be rapidly transferred to the absorbent body 2 arranged on the non-skin side of the assembly 50.例文帳に追加

Moreover, in order to secure such a thickness of the non-skin side portion, it is necessary to form the woven fabric 40 having a stable skeleton that does not easily collapse even when body pressure is applied while the napkin 1 is worn. Regarding this point, the relationship between the thickness of the twisted yarn of the woven fabric 40 and the thickness of the fibers 51 of the fiber assembly 50 will be described. For the thickness of the twisted yarn of the fabric 40, first, the fineness of the twisted yarn is randomly measured at, for example, 30 points, and the average value of the measured values is obtained. Next, the fineness of the fiber 51 is similarly measured at 30 points at random, and the average value of the measured values is obtained. For example, when the constituent yarn 41, which is the twisted yarn of the present embodiment, is of 30 cotton count, the average thickness (fineness) of the twisted yarn is approximately 19.68 tex (approximately 197 dtex). On the other hand, the average thickness (fineness) of the fibers 51 is approximately 3.4 dtex (0.34 tex). greater than the average value of

Since the twisted yarn is thick, the lattice-like skeleton structure formed by the twisted yarns of the fabric 40 is stable, and the napkin 1 is not easily crushed even when body pressure is applied while wearing, and the space (distance) to the absorbent body 2 is increased. Since it can be ensured, it is possible to suppress liquid return (rewet) to the fabric 40 .

As the cotton yarn used as the raw yarn, it is preferable to use a cotton yarn with a thickness of 10 to 100 cotton count, but even the thinnest twisted yarn with a cotton count of 100 has an average thickness. is larger than the average thickness of the constituent fibers 51 .

FIG. 8 is an enlarged view of a hydrophilic fiber 60, which is an example of hydrophilic fibers forming the fiber assembly 50. As shown in FIG. Such hydrophilic fibers 60 are thermoplastic resin fibers subjected to hydrophilic treatment, such as hydrophilic PET fibers, and have a plurality of grooves 61 along their extending direction. By having the plurality of grooves 61, the surface area in contact with the liquid is increased compared to the case where the outer peripheral surface is flat, and the capillary force of the grooves 61 facilitates the flow of the liquid, so the liquid drawing property is improved. improves.

As shown in FIG. 4, the fiber assembly 50 preferably exists in the space surrounded by the warp yarns 42 and the weft yarns 43, which are the constituent yarns 41 of the fabric 40, that is, in the texture 45. As shown in FIG. Since the fiber assembly 50 exists in the space surrounded by the constituent yarns 41 of the fabric 40 while being entangled with the textile 40, the liquid guided between the constituent yarns 41 is smoothly drawn into the fiber assembly 50, The liquid is further guided to the absorbent body 2 side along the fiber assembly 50 . As a result, it is possible to improve the drawability of the liquid.

In addition, in a plan view of the space (texture 45) surrounded by the constituent yarns 41 of the woven fabric 40, the area where the constituent fibers 51 of the fiber assembly 50 are present in the space is larger than the area where the constituent fibers 51 are not present in the same space. It may be smaller. In other words, in the space surrounded by the constituent yarns 41 of the woven fabric 40, although the constituent fibers 51 intertwined with the woven fabric 40 are present, the area where the constituent fibers 51 are not present may be larger. In the weave pattern 45 shown in FIG. 4, the area where the constituent fibers 51 are not present is larger, but it is not necessary that all the spaces (the weave pattern 45) are the same, and such spaces are at least One is enough.

Since the region where the constituent fibers 51 of the fiber assembly 50 do not exist is larger, a gap can be secured in the space surrounded by the constituent yarns 41 of the fabric 40, and air permeability between the fabric 40 and the fiber assembly 50 can be improved. can keep.

===Other Embodiments===

Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. Further, the present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.

Although cotton yarn is used as the raw yarn of the fabric 40 in the above-described embodiment, so-called unbleached cotton yarn may be used as the cotton yarn. Unbleached unbleached fabric contains natural pigments, cotton residue (cotton leaves and stem fragments), and a small amount of oil, so the color of the top sheet 3 is a light brown natural color. This gives the impression of a warm product that uses natural materials and is gentle on the skin. In addition, compared to the case of using a bleached white sheet, the redness of the menstrual blood absorbed by the absorber 2 is suppressed, so it is suitable for wearers such as minors who have just started menstruating. However, it is possible to reduce anxiety caused by directly viewing menstrual blood.

Moreover, the sheet portion 21 covering the absorbent core 10 may contain unbleached pulp fibers. For example, when used together with the topsheet 3 containing the unbleached fabric 40 described above, the light brown color derived from the natural material of the unbleached pulp fibers not only gives a more natural skin-friendly impression, but also reduces menstrual bleeding. It can contribute to concealability and antibacterial properties.

In the above-described embodiment, the liquid-permeable sheet for the absorbent article 1 according to the present invention is the topsheet 3 arranged closer to the skin than the absorbent body 2. It can also be used as a sheet, for example, an intermediate sheet located on the inner surface side of the top sheet, a core cover sheet, or the like.

1 sanitary napkin (absorbent article)
2 Absorber 3 Surface sheet (liquid-permeable sheet)
3a skin side 3b non-skin side 4 back sheet 5 side sheet 6 wing portion 7 compressed recess 8 outer peripheral seal portion 10 absorbent core 11 adhesive region 12 wing portion adhesive region 20 core wrap sheets 20a, 20b both side edges 21 sheet portion 40 Woven fabric 40a Lower surface 40b Upper surface 41 Constituent yarn 42 Warp yarn 43 Weft yarn 45 Texture 50 Fiber assembly 51 Constituent fiber 52 Skin-side extending portion 53 Non-skin-side extending portion 60 Hydrophilic fiber 61 Grooves L1, L2 Maximum distances D1, D2 Maximum thickness C1-C4 intersection

Claims (9)

a fabric having hydrophobic properties;
a non-woven fiber assembly comprising hydrophilic fibers, wherein some of the fibers are entangled with said fabric;
A liquid-permeable sheet for absorbent articles having
The fiber assembly includes a skin-side extending portion provided closer to the skin than the fabric and a non-skin-side extending portion provided closer to the non-skin side than the fabric, and the non-skin-side extending portion is provided. The maximum thickness of the portion is greater than the maximum thickness of the skin-side extending portion
A liquid-permeable sheet for an absorbent article characterized by: The liquid-permeable sheet for absorbent articles according to claim 1,
having a thickness direction,
The fiber assembly is arranged on the non-skin side of the woven fabric in the thickness direction,
A liquid-permeable sheet for an absorbent article, wherein the hydrophilicity of the fiber assembly is higher than the hydrophilicity of the woven fabric. The liquid-permeable sheet for absorbent articles according to claim 1 or 2,
having a thickness direction,
The constituent yarns of the fabric have a plurality of warp yarns that extend continuously and a plurality of weft yarns that extend continuously so as to intersect with the warp yarns in the thickness direction,
Among the fiber assembly, the fiber length of the longest fiber is longer than the maximum separation distance of at least one of the maximum separation distance between adjacent warp yarns and the maximum separation distance between mutually adjacent weft yarns of the fabric. ,
Among the fiber assembly, the fiber length of the shortest fiber is longer than the maximum distance of at least one of the maximum distance between adjacent warp yarns and the maximum distance between adjacent weft yarns of the fabric. A liquid-permeable sheet for an absorbent article characterized by: a fabric having hydrophobic properties;
a non-woven fiber assembly comprising hydrophilic fibers, wherein some of the fibers are entangled with said fabric;
A liquid-permeable sheet for absorbent articles having
The fiber assembly includes hydrophobic fibers,
A liquid-permeable sheet for an absorbent article, wherein the weight of the hydrophobic fibers contained per unit volume in the fiber assembly is larger than the weight of the hydrophilic fibers contained per unit volume. A liquid-permeable sheet for absorbent articles according to any one of claims 1 to 4 ,
A liquid-permeable sheet for an absorbent article, wherein the average thickness of the twisted yarns of the woven fabric is larger than the average thickness of the fibers of the fiber assembly. The liquid-permeable sheet for absorbent articles according to claim 1,
A liquid-permeable sheet for an absorbent article, wherein the hydrophilic fibers included in the fiber assembly have a plurality of grooves along the extending direction. A liquid-permeable sheet for absorbent articles according to claim 3,
A liquid-permeable sheet for an absorbent article, wherein the fiber assembly exists in a space surrounded by the constituent yarns of the woven fabric. A liquid-permeable sheet for absorbent articles according to claim 7 ,
A liquid-permeable sheet for an absorbent article, wherein, in a plan view of the space, a region where the fibers of the fiber assembly exist is smaller than a region where the fibers of the fiber assembly do not exist. a liquid-permeable sheet according to any one of claims 1 to 8 ;
an absorbent core that absorbs liquid;
An absorbent article comprising a sheet portion provided between the liquid-permeable sheet and the absorbent core,
The absorbent article, wherein the hydrophilicity of the sheet portion is higher than the hydrophilicity of the fiber assembly contained in the liquid-permeable sheet.

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