JP5210553B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article that absorbs liquid.

In an absorbent article such as a diaper or a sanitary napkin, if moisture is trapped between the user's skin and the absorbent article, the user will feel uncomfortable due to the stuffiness.
In view of this, an absorbent article has been proposed in which a surface sheet that comes into contact with the skin is formed into a concavo-convex shape to ensure a gap that can serve as a flow path for air (humidity). (See Patent Document 1)
Japanese Patent No. 3587831

However, the concavo-convex shape of the surface sheet described in Patent Document 1 is formed by partially heat-sealing a fiber assembly (fiber web) by heat embossing or the like. For this reason, in the concave portion where the fiber is heat-sealed, the fiber has a higher density than the convex portion.
In such an absorbent article, moisture (liquid) cannot smoothly pass through the recess, and moisture accumulates between the user's skin and the absorbent article, causing stuffiness.
Accordingly, an object of the present invention is to provide an absorbent article that is less likely to cause swelling.

In order to solve the problems as described above, the main present invention is a liquid-permeable top sheet, a liquid-impervious back sheet, and a liquid retaining property disposed between the top sheet and the back sheet. An absorbent article having an absorbent body, wherein the surface sheet has a concave portion and a convex portion so that the surface has a concave and convex shape, and the concave portion has less basis weight than the convex portion, and the absorbent body Is an absorbent article having high density absorbent resin interspersed portions , the absorbent body has absorbent fibers, and the fiber density of the absorbent fibers in the interspersed portions is outside the scattered portions. The end portion in the longitudinal direction of the absorbent body has a higher content of the interspersed portion than the central portion of the absorbent body in the longitudinal direction. It is an absorptive article characterized by being.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the absorbent article which is hard to produce stuffiness.

  This specification and the drawings disclose at least the following matters.

First, an absorbent article having a liquid-permeable top sheet, a liquid-impervious back sheet, and a liquid-retaining absorbent disposed between the top sheet and the back sheet, The top sheet has a concave portion and a convex portion so that the surface has an uneven shape, the concave portion has less basis weight than the convex portion, and the absorbent body has dotted portions where high-absorbent resin is densely packed. An absorbent article characterized by the above.
According to such an absorbent article, a user's skin and an absorber approach by the recessed part of a surface sheet, and since a fabric weight of a recessed part is low, moisture (liquid) becomes easy to be absorbed by an absorber. Furthermore, moisture that has passed through the recess can be more absorbed by the highly absorbent resin. That is, the above-described absorbent article is an absorbent article that is less likely to cause stuffiness. In addition, when the superabsorbent resin absorbs the liquid, there are dotted areas where the liquids are bonded to each other. Therefore, it is possible to prevent the absorption of the excreted liquid from being inhibited (blocking phenomenon). That is, since the top sheet can be kept in a dry state, it is difficult for stuffiness to occur. In addition, the user's skin and the absorbent body are moved away by the convex portion of the surface sheet, and the liquid can be prevented from returning.

In this absorbent article, the absorbent body has absorbent fibers, and the fiber density of the absorbent fibers in the interspersed portion is the fiber density of the absorbent fibers in the absorbent body outside the interspersed portion. Lower than.
According to such an absorbent article, it is possible to prevent the absorbent body from rising in the thickness direction when the superabsorbent resin retains a large amount of moisture and swells.

It is this absorbent article, Comprising: The edge part in the longitudinal direction of the said absorber has the content rate of the said scattered part higher than the center part of the said absorber in the said longitudinal direction.
According to such an absorbent article, the interspersed part located at the end part can play a role of moisture absorption until the liquid excreted in the central part moves to the end part side, and thus passes through the recessed part. Can absorb more moisture.

Such an absorbent article has a liquid-permeable second sheet between the absorbent body and the top sheet, and the second sheet is a nonwoven fabric with a fiber density higher than the average fiber density in the nonwoven fabric. A high-density region and a low-density region having a fiber density lower than the average fiber density, wherein the high-density region and the low-density region are from the topsheet side in the thickness direction of the nonwoven fabric to the absorber side To communicate with
According to such an absorbent article, a large amount of liquid or viscous liquid can be quickly passed through the low density region, and a small amount of liquid or liquid remaining in the top sheet can be absorbed by the high density region by capillary force. By drawing in, the liquid can be transferred to the absorber. In addition, while the liquid can be prevented from reversing by the thickness of the second sheet, the surface sheet is provided with a concave portion, so that the user's skin and the absorbent body can be prevented from moving too far away. , It becomes difficult to produce stuffiness.

In such an absorbent article, the top sheet is a non-woven fabric formed of a fiber assembly that is sprayed with a fluid and has an uneven surface.
According to such an absorbent article, the surface of the top sheet can be formed into a concavo-convex shape, and the basis weight of the concave portion can be made smaller than the basis weight of the convex portion.

=== About the Outline of the Absorbent Article of the Present Embodiment ===
Hereinafter, a sanitary napkin will be described as an example of the absorbent article. FIG. 1A is a top view of the sanitary napkin 1, and FIG. 1B is a cross-sectional view of the sanitary napkin 1. The sanitary napkin 1 (absorbent article) of the present embodiment has a liquid holding surface disposed between the liquid-permeable top sheet 2, the liquid-impermeable back sheet 5, and the top sheet 2 and the back sheet 5. Active absorbent body 4, second sheet 3 disposed between top sheet 2 and absorbent body 4, and side sheets 8 disposed on both ends in the width direction. Furthermore, the surface sheet 2 has the recessed part 7 and the convex part 6 so that the surface may become uneven | corrugated shape. And the recessed part 7 has less fabric weight than the convex part 6. FIG. Moreover, the absorber 4 has the interspersed part 48 where the highly absorbent resin 45 (SAP) is densely packed. In FIG. 1A, the interspersed portions 48 provided in the absorber 4 are virtually shown by dotted lines. The absorbent article of this embodiment having such a configuration can be used for liners, diapers and the like in addition to sanitary napkins.

  The sanitary napkin 1 has a shape that is long in a predetermined direction as a whole, and the predetermined direction is a longitudinal direction, and a direction that intersects the longitudinal direction is a width direction. The sanitary napkin 1 is mounted such that a portion from the front end portion to the rear end portion in the longitudinal direction of the sanitary napkin 1 is in contact with a portion from the user's abdomen to the buttocks. The side of the sanitary napkin 1 that contacts the body is the front side, the side that contacts the undergarment is the back side, and the direction normal to the front or back side of the sanitary napkin 1 is the thickness direction.

  Next, each component of the sanitary napkin 1 will be described in detail.

=== About Top Sheet 2 ===
FIG. 2A is a top view (surface) of the nonwoven fabric 10, and FIG. 2B is an enlarged perspective view of the nonwoven fabric 10. In the sanitary napkin 1 of this embodiment, the fluid f is sprayed and the nonwoven fabric 10 whose surface is uneven | corrugated shape is used for the surface sheet 2. FIG. Hereinafter, the nonwoven fabric 10 will be described in detail.

  First, the shape of the nonwoven fabric 10 will be described. On the surface side of the nonwoven fabric 10, a convex portion 6 along a direction corresponding to the longitudinal direction of the sanitary napkin 1 (hereinafter referred to as the longitudinal direction) has a direction corresponding to the width direction of the sanitary napkin 1 (hereinafter referred to as the width direction). The concave portions 7 (groove portions) are formed between the convex portions 6. That is, the convex portion 6 and the concave portion 7 are formed side by side in the width direction on the surface side of the nonwoven fabric 10. On the other hand, the back side is a substantially flat surface.

  The height of the convex portion 6 in the thickness direction is 0.3 mm or more and 15 mm or less (preferably 0.5 mm or more and 5 mm or less), and the length of the convex portion 6 in the width direction is 0.5 mm or more and 30 mm or less (preferably 1 mm). To 10 mm or less). In addition, the distance between the apexes of the convex portions 6 adjacent to each other with the concave portion 7 interposed therebetween (the central portion in the width direction) is 0.5 mm to 30 mm (preferably 3 mm to 10 mm).

  The height in the thickness direction of the concave portion 7 is 90% or less of the height of the convex portion 6 (preferably, the height in the range of 1% to 50% with respect to the convex portion 6). . The length of the concave portion 7 in the width direction is 0.1 mm or more and 30 mm or less (preferably 0.5 mm or more and 10 mm or less), and the distance between the central portions of the concave portions 7 adjacent to each other with the convex portion 6 interposed therebetween is 0.5 mm. It is 20 mm or less (preferably 3 mm or more and 10 mm or less).

Next, the manufacturing method of the nonwoven fabric 10 is demonstrated.
FIG. 3A is a diagram illustrating a state where the fluid f is sprayed on the fiber web 11, and FIG. 3B is a diagram illustrating an apparatus for manufacturing the nonwoven fabric 10.

  As shown in FIG. 3A, the nonwoven fabric 10 is a state in which a fiber web 11 having a substantially uniform thickness (corresponding to a fiber assembly and having a degree of freedom between fibers) is placed on a breathable support member 12. In addition, the fluid web 11 is manufactured by spraying the fluid f onto the fiber web 11 along a predetermined direction (MD direction, longitudinal direction) from the upper surface side (anti-supporting member side) of the fiber web 11. The fluid f sprayed on the fiber web 11 is a fluid (air flow) mainly composed of gas.

  The fiber web 11 includes thermoplastic resin fibers, and examples of thermoplastic resin fibers include single fibers made of polyethylene (hereinafter referred to as PE), polypropylene (hereinafter referred to as PP), polyethylene terephthalate, and the like, PE and PP, and the like. Or a composite fiber having a core-sheath structure composed of PE and PP. The fiber web 11 may contain fibers other than thermoplastic resin fibers, and may contain natural fibers such as cellulose, for example. Moreover, in order to improve whitening property, inorganic fillers, such as a titanium oxide, barium sulfate, a calcium carbonate, may contain, for example. In addition, a hydrophilic agent may be kneaded into the fiber if it is desired to improve the penetration of the liquid, and a water repellent agent may be kneaded into the fiber if it is desired to further prevent the liquid from returning.

  Specifically, the nonwoven fabric 10 is manufactured by a nonwoven fabric manufacturing apparatus as shown in FIG. 3B. A nonwoven fabric manufacturing apparatus is made to convey in the MD direction which is a conveyance direction in the state which supported the fiber web 11 from the bottom with the conveyor 13. FIG. In addition, the belt part 131 of this conveyor 13 becomes the air permeable support member 12 shown to FIG. 3A. The air-permeable support member 12 is a support member having a mesh structure having a flat surface, and is formed by weaving a plurality of wires having a predetermined thickness. This wire portion becomes a non-venting portion where the fluid f cannot be vented downward, and a space between the wires becomes a vent portion (hole) where the fluid f can be vented downward.

  In this way, the fiber web 11 is conveyed in the MD direction while being supported from below by the belt portion 131 that is the air-permeable support member 12, and first passes under the spraying device 14. The squirting device 14 includes a squirting unit 15, a squirting port 16, and an air intake unit 17, and the fluid f sent to the squirting unit 15 is ejected from the nozzle-like squirting port 16 toward the fiber web 11. .

  The ejection openings 16 are arranged in a line at equal intervals along the CD direction intersecting the MD direction, and the fiber web 11 is conveyed along the MD direction underneath, so that the fluid f is supplied to the fiber web 11. It is sprayed along the MD direction. Then, the fibers in the area where the fluid f is sprayed move in the CD direction, and the moved fibers blow to the area where the fluid f is not sprayed, that is, the area between the areas where the fluid f is sprayed. It is done. Thus, convex portions 6 and concave portions 7 along the MD direction are formed on the surface of the fiber web 11. That is, the area where the fluid f is sprayed becomes the concave portion 7, and the area where the fluid f is not sprayed becomes the convex portion 6 due to the movement of the fibers in the region which becomes the concave portion 7. (Fiber weight per unit area) is higher than the basis weight of the recess 7.

  At this time, since the fiber web 11 is supported from below by the air-permeable support member 12, the fibers in the region to which the fluid f is sprayed move along the surface of the air-permeable support member 12. Therefore, the breathable support member 12 side (back side) of the fiber web 11 has a substantially planar shape. Further, since the air-permeable support member 12 vents the fluid f sprayed on the fiber web 11 downward, the flow of the fluid f is prevented from being greatly changed, and a clean uneven shape is formed on the fiber web 11. be able to. If the support member is impermeable, the fluid f sprayed on the fiber web 11 may be rebounded by the support member, and the uneven shape may be disturbed.

  Moreover, since the fluid f sprayed on the fiber web 11 is sucked by the suction portion 17 provided below the belt portion 131, the fluid f can be prevented from bouncing back. Furthermore, since the fiber web 11 is pressed against the air-permeable support member 12 by the intake air and becomes stuck, the uneven shape formed on the fiber web 11 can be maintained.

  Thereafter, the fiber web 11 having the irregular shape formed on the upper surface side (front surface side) is further conveyed by the conveyor 13 and passes through the heater portion 18. In the heater part 18, the fiber web 11 is heat-processed, and as for the thermoplastic fiber in the fiber web 11, fibers are heat-seal | fused and the nonwoven fabric 10 whose surface is uneven | corrugated shape is manufactured.

  Further, the temperature of the fluid f sprayed on the fiber web 11 may be normal temperature. For example, in order to improve the moldability of the concavo-convex shape of the nonwoven fabric 10, a temperature higher than the softening point of the fiber web 11, preferably May be set to a temperature in the range of the softening point or higher and the melting point of −50 ° C. or higher and the melting point of +50 degrees or lower. If it is such temperature, since the fiber which comprises the fiber web 11 will soften and the repulsive force of fiber itself will fall, the uneven | corrugated shape formed when the fluid f was sprayed will become easy to be maintained. When the temperature of the fluid f is further increased, the uneven shape is easily maintained while the uneven shape is formed on the surface and the heat fusion between the fibers is started. In this case, since the fibers are heat-sealed by the fluid f, the heat treatment by the heater unit 18 in FIG. 3B can be omitted.

  In addition, while the fiber web 11 is transported from the spraying device 14 to the heater unit 18 in order to transport the fiber web 11 to the heater unit 18 while maintaining the uneven shape of the fiber web 11 by the fluid f, from below the belt unit 131. Suction or a heater unit 18 may be provided immediately downstream of the spraying device 14. In addition, when the fluid f is hot air, the formed uneven shape may be gradually cooled by cold air or the like immediately after forming so that the formed uneven shape is gradually deformed by residual heat and the uneven shape is not destroyed.

The average fabric weight of the nonwoven fabric 10 thus manufactured is manufactured so as to be 10 g / m ² or more and 200 g / m ² or less (preferably 20 g / m ² or more and 100 g / m ² or less). If the average fabric weight of the nonwoven fabric 10 is smaller than 10 g / m ² , the nonwoven fabric 10 is easily broken. If the average fabric weight is larger than 200 g / m ² , it is difficult for the liquid to move downward (absorber). .

  By the way, in the nonwoven fabric 10 of this embodiment, since the uneven | corrugated shape is formed in the surface by spraying the fluid f along MD direction to the fiber web 11, as shown to FIG. It contains a relatively large amount of fibers oriented in the direction (fibers oriented in an arbitrary direction in the range of −45 ° to + 45 ° with respect to the CD direction). On the other hand, both end portions in the CD direction of the convex portion 6 include fibers in which fibers are blown from the region to be the concave portion 7, and therefore fibers oriented in the MD direction (range from −45 ° to + 45 ° with respect to the MD direction). A relatively large amount of fibers facing in any direction. Both end portions in the CD direction of the convex portion 6 are side portions 62, and a region between the side portions 62 in the convex portion is a central portion 61.

And the fabric weight of the side part 62 of the convex part 6 is higher than the fabric weight of the center part 61. FIG. Specifically, the basis weight of the central portion 61 of the convex part 6 is 15 g / m ² or more and 250 g / m ² or less (preferably 20 g / m ² or more and 120 g / m ² or less), and the basis weight of the side part 62 is 20 g. / M ² or more and 280 g / m ² or less (preferably 25 g / m ² or more and 150 g / m ² or less).
The basis weight of the recesses is 3 g / m ² or more and 150 g / m ² or less (preferably 5 g / m ² or more and 80 g / m ² or less).

Furthermore, in the nonwoven fabric 10 (surface sheet 2) of this embodiment, it adjusts so that the fiber density of the recessed part 7 may become lower than the fiber density of the convex part 6. FIG.
Specifically, the fiber density of the concave portion 7 is set to 0.002 g / cm ³ or more 0.18 g / cm ³ or less (preferably 0.005 g / cm ³ or more 0.05 g / cm ³ or less), the convex portion 6, 0.005 g / cm ³ or more 0.20 g / cm ³ or less (preferably 0.007 g / cm ³ or more 0.07 g / cm ³ or less).

  The uneven shape of the nonwoven fabric 10 (the size of the unevenness, the basis weight of the fibers, and the fiber density) is determined by the air volume and temperature of the fluid f sprayed on the fiber web 11 when the nonwoven fabric 10 is manufactured, the amount drawn by the intake portion, and the breathable support member 12. The air permeability can be adjusted. For example, by increasing the size of the ejection port 16, the height of the convex portion 6 can be increased, and by reducing the size of the ejection port 16, the height of the convex portion 6 can be decreased. it can.

As described above, the sanitary napkin 1 (absorbent article) using the nonwoven fabric 10 as the surface sheet 2 having a concave-convex surface and a basis weight of the concave portion 7 smaller than that of the convex portion 6 makes it difficult to cause stuffiness. be able to.
This is because the concave portion 7 on the surface of the surface sheet 2 can bring moisture between the user's skin and the surface sheet closer to the absorber 4, and the concave portion 7 of the present embodiment has a lower basis weight than the convex portion. This is because moisture is easily absorbed by the absorber 4 because there is little resistance due to the fibers.

  However, in order to improve moisture absorption, if the thickness of the entire surface sheet 2 is made thin like the concave portion 7 and the basis weight is made low like the concave portion 7, the surface sheet 2 is easily damaged, and the liquid is on the surface. It becomes easy to go back on the sheet 2. If it does so, a user's skin will be polluted and an unpleasant feeling (stickiness) will be given to a user.

  Then, like the surface sheet 2 of this embodiment, it is easy to absorb moisture by providing both the concave portion 7 and the convex portion 6 having a higher basis weight than the concave portion 7, and the convex portion 6 allows the user's skin to be absorbed. And the absorber 4 can be kept away and liquid return can be prevented. Moreover, the ease with which the recessed part 7 is damaged can be supplemented with the convex part 6, and the surface sheet 2 can be made strong. Furthermore, since the thickness of the surface sheet 2 can be increased by the convex portion 6, the cushioning property is improved, and the user's comfort can be improved.

  Moreover, even if the nonwoven fabric has a concave portion and a convex portion, for example, in the case of a nonwoven fabric whose surface is formed into an uneven shape by hot embossing a part of a fiber web having a substantially uniform thickness, the concave portion is The basis weight does not become lower than the convex portion, and the concave portion has a higher density of fibers than the convex portion, and moisture is hardly absorbed by the absorber. If it does so, moisture will retain between a user's skin and a crevice, and a dullness will arise.

  That is, as in the present embodiment, the nonwoven fabric 10 is manufactured by spraying the fluid f onto the fiber web 11 (air flow treatment), whereby the nonwoven fabric 10 having a lower basis weight of the concave portion 7 than that of the convex portion 6 is applied to the surface sheet. It is possible to provide a sanitary napkin (absorbent article) that can be used as No. 2 and is less likely to cause stuffiness and liquid return. And since the recessed part 7 is easy to let not only moisture but a liquid also pass through, for example, when a large amount of liquid is excreted, a liquid can be rapidly transferred to the absorber 4. Moreover, since the recessed part 7 has little resistance by a fiber, a highly viscous liquid can also pass through.

  Further, the nonwoven fabric 10 is formed with a concave portion 7 and a convex portion 6 along the MD direction, and the nonwoven fabric 10 is arranged as the top sheet 2 so that the MD direction of the nonwoven fabric 10 is the longitudinal direction of the sanitary napkin 1. The Since the surface sheet 2 enters the eyes of the user, it is preferable in terms of appearance that the concave portions 7 and the convex portions 6 are formed along the longitudinal direction.

  In addition, since the surface of the surface sheet 2 is uneven, only the convex portion 6 comes into contact with the user's skin, and the contact area between the user's skin and the sanitary napkin can be reduced. , Can reduce the burden on the skin.

  Moreover, since the surface of the surface sheet 2 has an uneven shape, the liquid excreted on the surface sheet 2 enters the recess 7, and the diffusion of the liquid in the width direction can be blocked by the protrusion 6. In addition, since most of the fibers contained in the concave portion 7 of this embodiment are oriented in the width direction (CD direction) (FIG. 2A), the liquid that has entered the concave portion 7 is difficult to diffuse in the longitudinal direction.

  Like the nonwoven fabric 10 of this embodiment, by manufacturing the nonwoven fabric 10 (surface sheet 2) so that the fiber density of the recessed part 7 becomes lower than the fiber density of the convex part 6, liquid and moisture are further increased by the recessed part 7. It becomes easy to make it transfer to the absorber 4, and the liquid return is further prevented by the convex portion 6. Moreover, the convex part 6 becomes difficult to be crushed by external pressure etc. by making the fiber density of the convex part 6 high.

  In particular, the side portion 62 where the fibers are blown by the fluid f among the convex portions 6 has a high fiber density. Therefore, even if a small amount of liquid remains in the recess 7 after most of the excreted liquid has moved to the absorber 4 by the recess 7, the liquid is transferred to the absorber 4 by the capillary force of the side portion 62 adjacent to the recess 7. Can be migrated. And since the back surface side of the surface sheet 2 (nonwoven fabric 10) is a flat surface and the entire back surface of the surface sheet 2 is in contact with the second sheet 3 (or the absorbent body 4), it has reached the back surface side of the surface sheet 2. The liquid can move smoothly to the second sheet 3 and further to the absorber 4. That is, it is difficult for the liquid to remain on the top sheet 2, and as a result, it is possible to prevent the user from feeling sticky.

=== About the second sheet 3 ===
4A is a perspective view of the second sheet 3, and FIG. 4B is a cross-sectional view of the second sheet 3. The sanitary napkin 1 of the present embodiment is provided with a second sheet 3 between the top sheet 2 and the absorbent body 4. By making the average fiber density of the second sheet 3 higher than the average fiber density of the top sheet 2 and making the liquid drawing property of the second sheet 3 better than that of the top sheet 2, the excreted liquid is smoothly transferred to the absorber 4. can do.
Further, by providing the second sheet 3, the absorbent body 4 and the user's skin can be separated by the thickness of the second sheet 3, so that rewetting is prevented. However, from the viewpoint of preventing stuffiness, the provision of the second sheet 3 makes the absorber 4 and the user's skin far away, making it difficult for moisture to be absorbed. However, the surface of the topsheet 2 of the present embodiment has an uneven shape, and the recesses 7 can prevent the absorber 4 and the user's skin from being too far away.

  The second sheet 3 of the present embodiment is a non-woven fabric 3 ′ having a substantially uniform thickness, a high-density region 31 having a fiber density higher than the average fiber density of the whole non-woven fabric, and a fiber density lower than the average fiber density. And a low density region 32. And as shown to FIG. 4A, the high density area | region 31 and the low density area | region 32 are disperse | distributed and formed in the surface direction of nonwoven fabric 3 ', and as shown to FIG. 4B, the high density area | region 31 and the low density area | region 32 and Are communicated from the front surface side to the back surface side in the thickness direction of the nonwoven fabric 3 '. Further, in the high-density region 31, the fiber density on the back surface side is higher than the fiber density on the front surface side.

  Incidentally, in the absorbent article of this embodiment, it arrange | positions so that the surface side of this nonwoven fabric 3 'may face the surface sheet 2 side. That is, the high density region 31 and the low density region 32 communicate from the top sheet 2 to the absorbent body 4 side, and the fiber density on the absorbent body 4 side is higher than the fiber density on the top sheet 2 side in the high density region 31. It has become.

  Hereinafter, the manufacturing method of nonwoven fabric 3 'used as the second sheet | seat 3 is demonstrated. FIG. 5A to FIG. 5D are diagrams showing a method of manufacturing the nonwoven fabric 3 ′. The nonwoven fabric 3 'is a heat-treated fiber in which the fiber web 34, in which one or more kinds of heat-shrinkable fibers having heat-fusible properties are blended, is placed on the support member 33, and the heat-fused fibers. The non-woven fabric 3 ′ is obtained by pressing from the surface opposite to the support member 33, and the manufacturing method is different from the non-woven fabric used for the top sheet 2 described above.

  Here, examples of the heat-shrinkable fiber include an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage rates as components. Examples of thermoplastic polymer materials having different shrinkage rates include a combination of ethylene-propylene random copolymer and polypropylene, a combination of polyethylene and ethylene-propylene random copolymer, a combination of polyethylene and polyethylene terephthalate, and the like.

  First, a fiber web 34 having a predetermined thickness is continuously formed by opening a raw material in which heat-shrinkable fibers having heat-fusibility and heat-fusible fibers are mixed using a card device or the like (not shown). To form. Further, in the formed fiber web 34, the heat-shrinkable fibers and the heat-fusible fibers do not necessarily exist evenly, and a region where the heat-shrinkable fibers are gathered and a region where the heat-shrinkable fibers are not gathered are formed. A fiber web may be formed from a plurality of types of heat-shrinkable fibers. Further, the fiber web may be formed not only by the card method but also by the airlaid method.

  Then, as shown in FIG. 5A, the fiber web 34 is placed on a breathable net 33 (a plate-like support member having a flat surface or a mesh structure) with a predetermined temperature. Heat treatment. That is, the fiber web 34 is heat-treated while being supported from the lower side. The predetermined temperature is a temperature at which the heat-shrinkable fiber melts and heat-shrinks.

  As a result, as shown in FIG. 5B, each fiber in the fiber web 34 melts and fuses with other fibers to form a fiber cloth 34 'in which the fibers are heat-sealed. Further, an uneven structure (sea island structure) is formed on the surface (free surface) of the fiber cloth 34 ′ opposite to the side supported by the air-permeable net 33. On the other hand, the surface (support surface) on which the fiber cloth 34 ′ is supported is substantially flat along the surface of the breathable net 33.

  During the heat treatment, the heat-shrinkable fibers on the free surface side of the fiber web 34 are not shrunk, and thus freely shrink in the surface direction while surrounding fibers (such as heat-fusible fibers) are involved. That is, the convex portion 35 in the concavo-convex structure is a region where the heat-shrinkable fibers are gathered, and has a large number of fibers taken into the heat-shrinkable fibers by taking advantage of the heat-shrinkable fibers. Therefore, the basis weight of the convex portion 35 is higher than the average basis weight of the fiber cloth 34 ′. On the other hand, the recess 36 is an area where heat shrinkable fibers are not so much originally present and the heat fusible fibers are taken in and moved by the surrounding heat shrinkable fibers. The basis weight is lower than the basis weight. Moreover, since the fiber which existed in the recessed part 36 moves to the convex part 35 by heat processing, the convex part 35 and the recessed part 36 are formed adjacently.

  Thereafter, as shown in FIG. 5C, the free surface side on which the concavo-convex structure of the fiber cloth 34 'is formed is pressed so that the convex portion 35 is crushed in the thickness direction. At this time, when the pressure is pressed to a thickness equal to or less than the thickness of the concave portion 36, a non-woven fabric 3 'having substantially the same thickness is obtained as shown in FIG. 5D. Further, when the fiber cloth 34 ′ is heated at a predetermined temperature during pressing, the convex portion 35 is easily crushed, and the free surface side that is the uneven shape can be made more planar. A region where the convex portion 35 is crushed becomes a high density region 31, and a region which is the concave portion 36 becomes a low density region 32. Further, since the convex portion 35 and the concave portion 36 are formed adjacent to each other, it can be said that the high density region 31 and the low density region 32 are also adjacent to each other in the plane direction.

  Moreover, since the high density area | region 31 is formed by pressing the convex part 35 by the side of the free surface of fiber cloth 34 ', the fiber density of the free surface side becomes higher than the fiber density of the support surface side. Yes. That is, the free surface in FIG. 5D corresponds to the back surface of the nonwoven fabric 3 ′ shown in FIG. 4B, and the support surface in FIG. 5D corresponds to the surface of the nonwoven fabric 3 ′ shown in FIG. 4B.

In order to suitably obtain the nonwoven fabric 3 ′ in which the high density region 31 and the low density region 32 are dispersed in the plane direction and the high density region 31 and the low density region 32 are communicated from the free surface to the support surface. The basis weight (2Xg / m ² ) of the convex portion 35 at the time when the fiber web 11 is heat-treated (FIG. 5B) is more than twice the basis weight (Xg / m ² ) of the concave portion 36 and the concave portion 36 It is good to press to below the thickness. Therefore, if the “fiber physical properties” and “manufacturing conditions” are controlled, it is possible to form an uneven structure of a desired fiber.

=== About Absorber 4 ===
FIG. 6A is a diagram showing a top view of the absorber 4. The outline of the sanitary napkin 1 is virtually indicated by a dotted line. The absorber 4 includes an absorber material 43 and a covering material that covers the absorber material 43. The absorbent body material 43 is composed of absorbent fibers 44 and superabsorbent resin 45. An example of the absorbent fiber 44 is a pulp fiber (pulp pulverized into a fiber shape), and the pulp fiber is used by being accumulated in a sheet shape. An example of the superabsorbent resin 45 is a granular superabsorbent polymer (hereinafter referred to as SAP). In the absorbent body 4 of the present embodiment, SAP is partially concentrated in the absorbent body material 43 and is not evenly dispersed (details will be described later). In addition to the pulp fiber, the absorbent material 43 includes cellulose such as cotton, regenerated cellulose such as rayon and fibration, semi-synthetic cellulose such as acetate and triacetate, fibrous polymer, thermoplastic hydrophobic chemical fiber, and the like. It may be.
Further, the covering material covering the absorbent body material 43 is a sheet having liquid permeability and finer than the particle diameter of the SAP, and prevents the SAP and pulp fibers from leaking outside the covering material. have. An example of the covering material is a thin paper such as a tissue paper.
And in the absorber 4 of this embodiment, in order to integrate a coating | covering material and the absorber raw material 43, the predetermined part of the absorber 4 is squeezed and the emboss is formed in the said part.

  In the sanitary napkin 1 having such an absorbent body 4, the excreted liquid is sucked by the absorbent fibers 44 (pulp fibers accumulated in a sheet shape) and penetrates into the absorbent body material 43. Thereafter, the liquid is repeatedly excreted, whereby the liquid inside the absorbent body material 43 diffuses within the absorbent body material 43 and is finally collected by the SAP (super absorbent resin 45). Note that SAP has a property of swelling when moisture is collected, and is a material excellent in hygroscopicity. Therefore, the SAP before collecting moisture mainly plays a role of absorbing moisture, and an effect of preventing stuffiness is obtained by the SAP. Moreover, in the surface sheet 2 of this embodiment, since the recessed part 7 with a low basis weight makes it easy for the absorbent body 4 to absorb moisture, providing the SAP with the absorbent body 4 absorbs moisture more.

  And as for the absorber 4 of this embodiment, as shown to FIG. 6A, the part located in the center part in a longitudinal direction and the width direction is formed with the bulging part 41 which swelled to the skin surface side. The bulging portion 41 is formed in an oval shape, and conforms to the shape of the crotch portion of the user when the user wears the sanitary napkin 1, and the crotch portion and the absorbent body 4 include the topsheet 2 and the second sheet. The sheet 3 can be brought into close contact with each other, and liquid leakage can be prevented.

  The skin 4 side of the absorbent body 4 and the second sheet 3 are joined by a hot melt adhesive HMA, and the absorbent body 4, the second sheet 3 and the top sheet 2 are deep grooves pressed in the thickness direction using a high-temperature pressing member. The deep grooves 47 formed by embossing are further firmly joined. As shown in FIG. 6A, the deep groove portion 47 is formed in a region surrounding the bulging portion 41 and a region extending from the front to the rear in the longitudinal direction of the sanitary napkin 1 on both sides of the bulging portion 41. In the deep groove portion 47, shallow bottom portions and deep bottom portions having different groove depths are alternately arranged. By forming such a deep groove portion 47, when the sanitary napkin 1 is mounted, it is easy to bend along the body so that the surface side of the sanitary napkin 1 has a mountain shape. As a result, the sanitary napkin 1 can be brought into close contact with the body groove and the like, and it is difficult for the liquid to leak. Moreover, since the liquid excreted by the bulging part 41 enters the deep groove part 47, it is possible to prevent the liquid from diffusing in the surface direction of the sanitary napkin 1.

  FIG. 6B is a cross-sectional view of the interspersed portion 48. The interspersed portion 48 is a region where SAP (superabsorbent resin) is densely formed, is formed in an oval shape, and the interspersed portions 48 are arranged on the front end side and the rear end side of the bulge portion 41. . An embossing process 46 is applied to a portion corresponding to the periphery of the outer periphery of the interspersed portion 48. The rear end portion includes more interspersed portions 48 than the front end portion. This is because when the user lies down at bedtime or the like, the liquid easily moves to the rear end side (waist side).

  In the interspersed portion 48, SAP and pulp fibers are mixed, but in the absorbent body material 43 outside the interspersed portion 48, the pulp fibers are concentrated almost uniformly and do not have SAP. And the fabric weight of the pulp fiber of the scattered part 48 is lower than the fabric weight of the pulp fiber outside the scattered part. This is because SAP swells when it absorbs moisture. If the interspersed part 48 has the same basis weight of the pulp fiber as the area outside the interspersed part, when the SAP absorbs moisture, the SAP swells, and accordingly, the interspersed part expands in the thickness direction. Resulting in. If it does so, it will be in the state where a part of absorber 4 which was a substantially plane rose, and will make a user feel a level difference (discomfort). That is, in the interspersed portion 48, a space is provided in advance so that the SAP may swell by making the basis weight of the pulp fibers lower than the region outside the interspersed portion.

  Moreover, SAP is collected in a part (by providing the interspersed part 48) without dispersing SAP evenly in the absorbent body material 43, and the SAPs are bonded to each other. A phenomenon (blocking phenomenon) that hinders the diffusion of moisture in the absorbent body material 43 can be prevented. If the blocking phenomenon occurs, moisture that has penetrated to the absorbent body material 43 may stay on the skin surface side of the absorbent body material 43, and the absorbent capacity of the sanitary napkin 1 may be reduced. If it does so, a liquid will remain in the surface sheet 2 or the 2nd sheet | seat 3, and the surface sheet 2 cannot be maintained in a dry state, and it becomes easy to produce stuffiness.

  Further, in the present embodiment, the interspersed portion 48 is not provided in the bulging portion 41. The reason is that once the SAP absorbs the liquid, it is difficult for the liquid to escape. Therefore, in the bulging portion 41 that needs to absorb the liquid repeatedly, it is necessary to move the liquid forward or backward without holding the liquid. It is. By doing so, it becomes possible to use the absorber 4 effectively over the entire surface.

  In addition, the sanitary napkin 1 is folded in three at two folding line positions during product packaging. As shown in FIG. 6A, there are interspersed portions 48 at locations corresponding to the folding line positions when folding. Since the interspersed portion 48 has a low pulp fiber content and low rigidity, the sanitary napkin 1 can be easily folded by providing the interspersed portion 48 at the folding line position.

=== About other components ===
On the back surface side (anti-skin surface side) of the absorbent body 4, the back surface sheet 5 is bonded with a hot melt adhesive HMA. Further, a side sheet 8 is joined to the skin surface side of the absorbent body 4 by a hot melt adhesive from a position slightly overlapping each side of the absorbent body 4 to the back sheet 5. And the round seal process which heat-welds the outer edge part of the sanitary napkin 1 at low temperature is given, and the 2nd sheet | seat 3 and the absorber 4 are hold | maintained between the surface sheet 2 and the back surface sheet 5. FIG.

<Back sheet 5>
The back sheet 5 is a sheet member having liquid impermeability. The back sheet 5 is formed of a film sheet made of a resin such as polyethylene or polypropylene. The back sheet 5 is formed sufficiently wider than the absorbent body 4 on the opposite surface side of the sanitary napkin 1, and the outer edge portion thereof is located outside the outer edge portion of the absorbent body 4 in the entire circumference. An adhesive is provided on the back side of the back sheet 5, and the sanitary napkin 1 is adhered to the inside of the underwear by an adhesive interposed between the back sheet 5 and the underwear.
Wings 9 extending outward in the width direction are formed on both sides in the width direction. When the sanitary napkin 1 is worn, the wing portion 9 is fixed to the undergarment while being folded back to the opposite surface side.
The back sheet according to the present embodiment is a liquid-impermeable sheet formed from thermoplastic fibers such as polyethylene and polypropylene, but includes a thermoplastic and liquid-impermeable sheet, and is laminated with thin paper or nonwoven fabric. Alternatively, a sheet member may be used.

<Side sheet 8>
The side sheet 8 is a sheet that overlaps a part of the top sheet 2 (more precisely, both ends in the width direction of the top sheet 2), and the width of the sanitary napkin 1 on the skin surface side of the sanitary napkin 1. It is provided at the direction end. The side sheet 8 is formed of an appropriate nonwoven fabric such as an air-through nonwoven fabric, a spunbond nonwoven fabric, or a nonwoven fabric composed of a spunbond meltblown spunbond layer formed of synthetic resin fibers.

=== About the function of the sanitary napkin 1 ===
7A to 7D are diagrams showing the absorption behavior of the liquid 50 excreted by the sanitary napkin 1. The drawing is a cross-sectional view of the bulging portion 41 that does not have the interspersed portion 48.

  As shown in FIG. 7A, it is assumed that a liquid 50 such as menstrual blood is excreted on the top sheet 2 of the sanitary napkin 1. Then, since the excreted liquid 50 first enters the concave portion 7 between the convex portion 6 and the convex portion 6, diffusion of the liquid 50 on the topsheet 2 in the width direction is blocked by the convex portion 6. Can do. Thus, by making the surface of the topsheet 2 uneven, and reducing the diffusion area of the liquid 50 on the topsheet 2, the contact area between the topsheet 2 wetted by the liquid 50 and the user's skin is reduced. be able to. Moreover, since the surface sheet 2 is in the eyes of the user, it is visually preferable that the diffusion area of the liquid 50 (menstrual blood) is small.

  And in this embodiment, since it adjusted so that the average fiber density of the second sheet 3 may become higher than the average fiber density of the surface sheet 2, most of the liquid 50 on the surface sheet 2 is a fiber. It can pass through the top sheet 2 with low resistance and can quickly move to the second sheet 3. In particular, since the concave portion 7 of the top sheet 2 is closer to the second sheet 3 than the convex portion 6 and has a lower fiber density than the convex portion 6, the liquid 50 is easily transferred to the second sheet 3.

  Thereafter, the liquid 50 that has reached the surface side of the second sheet 3 passes through the low density region 32 of the second sheet 3 and moves to the absorber 4 as shown in FIG. 7B. Since the low density region 32 of the second sheet 3 communicates in the thickness direction, the liquid 50 can be quickly transferred to the absorber 4. Therefore, similarly to the top sheet 2, also in the second sheet 3, diffusion of the liquid 50 in the surface direction can be suppressed. Moreover, even if it is a highly viscous liquid, it can pass through the recessed part 7 of the surface sheet 2, and the low density area | region 32 of the second sheet 3, and can transfer to the absorber 4. FIG.

  And after most liquid 50 transfers to the absorber 4, as shown to FIG. 7C, the liquid 50 which remains on the surface sheet 2 is the capillary of the side part 62 (convex part 6) with high fiber density. It is drawn into the surface sheet 2 by force. Then, the liquid remaining in the top sheet 2 is drawn into the second sheet 3 (high density region 31) by the capillary force of the high density region 31 of the second sheet 3. Furthermore, in the high density region 31, the fiber density on the absorbent body 4 side is higher than that on the top sheet 2 side, so that the drawn liquid 50 can be transferred to the absorbent body 4 by capillary force. In addition, since the pulp fibers are laminated in the absorbent body 4, the absorbent body 4 has a higher fiber density than the high-density region 31. Further, the liquid 50 remaining in the low density region 32 of the second sheet 3 can also be transferred to the absorber 4 by the capillary force of the high density region 31.

  That is, it can be said that the sanitary napkin 1 (absorbent article) of the present embodiment is a sanitary napkin 1 in which the liquid quickly moves to the absorbent body 4 without diffusing in the surface direction and the liquid hardly remains. According to such a sanitary napkin 1, the excreted liquid surely moves to the absorbent body 4, and after excretion of the liquid, the top sheet 2 and the second sheet 3 are dried to a predetermined state. It is possible to prevent the user from getting dirty or giving the user an unpleasant feeling (sticky feeling). In addition, the liquid can be repeatedly excreted.

  The liquid thus transferred to the absorber 4 diffuses in the surface direction as the liquid is repeatedly excreted. In particular, the top sheet 2 and the second sheet 3 of this embodiment have good liquid transferability (because the liquid is difficult to diffuse in the surface direction), and most of the liquid is absorbed into the bulging portion 41 that comes into contact with the body's excretion opening. Is done. Therefore, the liquid in the bulging part 41 moves forward and rearward of the bulging part 41 and is finally absorbed and held by the superabsorbent resin (SAP) of the interspersed part 48. Since SAP can hold a large amount of liquid as described above, even if liquid is repeatedly excreted, there is little risk of overflowing the liquid.

  Further, once the superabsorbent resin (SAP) absorbs the liquid, it is difficult for the liquid to escape. Therefore, the absorber 4 having SAP is unlikely to return (rewet) the liquid back to the topsheet 2 side. In particular, in the present embodiment, since the convex portion 6 is provided on the topsheet 2 so that the liquid does not reverse, the absorbent body 4 and the user's skin are kept as far away as possible. By providing the SAP, it is possible to provide the sanitary napkin 1 in which the liquid is less likely to return.

  Of the absorbent material 43, moisture is also absorbed by the absorbent fibers 44 (pulp fibers), but more than that, the superabsorbent resin (SAP) is excellent in hygroscopicity. Therefore, until the liquid absorbed by the absorber 4 (the bulging part 41) moves to the interspersed part 48 having SAP, the interspersed part 48 (SAP) mainly absorbs moisture and makes it difficult to cause stuffiness. be able to. In particular, in the present embodiment, the surface sheet 2 is provided with the low weight per unit area (low fiber density) concave portion 7 so that moisture is easily absorbed. Thus, it is possible to provide the sanitary napkin 1 (absorbent article) that is less likely to cause stuffiness.

=== Second Embodiment ===
In the above-described embodiment, the second sheet 3 is disposed between the top sheet 2 and the absorbent body 4, but is not limited thereto. For example, as in the second embodiment (not shown), the absorbent body 4 has a surface sheet 2 having a concavo-convex surface and a recessed portion with a smaller basis weight than the protruding portion, and dotted portions where highly absorbent resins are densely packed. If it is an absorptive article which has, even if it does not distribute second sheet 3 between surface sheet 2 and absorber 4, an absorptive article which cannot produce stuffiness can be provided.

  In the case of the absorbent article according to the second embodiment, the absorbent body 4 (especially SAP) and the concave portion 7 of the topsheet 2 can be brought closer to each other by the thickness of the second sheet 3 as compared with the above-described absorbent article. Can absorb moisture more. As a result, the absorbent article of the second embodiment is less likely to cause swelling than the above-described absorbent article.

  However, since the absorbent article described above can separate the absorbent body 4 and the user's skin by the thickness of the second sheet 3 than the absorbent article of the second embodiment, the liquid returns. It becomes difficult to do.

  Further, as in the above-described embodiment, by providing the second sheet 3, the liquid remaining in the top sheet 2 can be drawn into the second sheet 3 and transferred to the absorber 4. Therefore, as a modified example of the second embodiment, the second sheet 3 is provided only in a region (for example, the bulging portion 41) that contacts the body excretion opening, and the front side and the rear side of the absorbent article in which the interspersed portions 48 are arranged. An absorbent article (not shown) in which the second sheet 3 is not disposed on the side can be proposed. In the case of such an absorbent article, the area where the liquid is excreted can be transferred to the absorbent body 4 without the liquid remaining by the second sheet 3, and the front side of the absorbent article where the second sheet 3 is not disposed. In the rear region, moisture can be brought close to the absorber 4 (SAP), so that it is difficult to cause stuffiness.

=== About the evaluation test of an absorbent article ===
The above surface sheet and second sheet (nonwoven fabric) were actually produced, and rewetting property was evaluated. First, a method for evaluating rewetting is described.

<Method for evaluating rewetting>
The following instruments are used as measuring instruments.
1) Artificial menstrual blood 2) Autoburette (Metrohm 725 type)
3) Scale 4) Perforated acrylic plate (40mm x 10mm hole in the center, length x width = 200mm x 100mm, weight 125g)
5) Acrylic board (length x width = 100 mm x 70 mm, weight 45 g in order to apply weight load evenly to the filter paper)
6) Weight 7) Stopwatch 8) Filter paper (Advantech Toyo No.2, length x width = 50mm x 35mm)

In addition, the artificial menstrual blood mix | blends the following with respect to 1 liter of ion-exchange water. (1) Glycerin 80 g (2) Sodium carboxymethylcellulose (NaCMC) 8 g (3) Sodium chloride (NaCl) 10 g (4) Sodium bicarbonate (NaHCO3) 4 g (5) Red No. 102 8 g (6) Red No. 2 2 g (7 ) Yellow No.5 2g

The evaluation procedure is as follows.
1) Measure the weight of 10 filter papers. ... A
2) Place the acrylic plate on the evaluation object so that the center of the hole in the acrylic plate and the center of the evaluation object (nonwoven fabric + absorbent) overlap.
3) Set the nozzle of the auto burette to a position 10 mm above the acrylic plate.
4) Drip artificial menstrual blood. (Speed: 95 ml / min, dripping amount: 6 ml)
5) One minute from immediately after the artificial menstrual blood is brushed from the surface of the nonwoven fabric, 10 sheets of filter paper are placed so as to match the center of the topsheet, and the acrylic plate is applied so that the applied force is 50 g / cm 2 in total. Stack the weights (without holes).
6) After 1 minute, remove the weight, the acrylic plate, and measure the weight of the filter paper. ... B
From the measurement results A and B, the rewetting rate is calculated.
Rewetting rate (%) = ((B−A) × 100) / (drop amount = 6 ml)

<Evaluation of non-woven fabric>
The production conditions and evaluation results of the actually produced nonwoven fabric (surface sheet, second sheet) will be described below. FIG. 8 is a table for explaining the constituent fibers of the nonwoven fabric used for the evaluation. As shown in the table of FIG. 8, the comparison surface sheet a (nonwoven fabric manufactured by the air-through manufacturing method) and the implementation surface sheet b (nonwoven fabric 10 manufactured by the air flow treatment shown in FIG. 3A described above) and comparison A second sheet c (nonwoven fabric manufactured by an air-through manufacturing method) and an implementation second sheet d (nonwoven fabric 3 ′ whose manufacturing method was shown in FIG. 5 described above) were manufactured. And the rewet rate of the evaluation target object which combined these four types of nonwoven fabrics and an absorber was measured.

The absorption body are all common, fluff pulp of 500 g / ^{m 2} wrapped in 15 g / ^{m 2} tissue (thin paper), (not including SAP) that are produced by applying a flat press. The density of the absorber is adjusted to 0.09 g / cm ³ . And the hinge press is given so that a nonwoven fabric (a surface sheet, a second sheet) may not float from an absorber. The hinge shape is convex on the inside, the narrowest part is 38 mm, and an adhesive is disposed on the hinge part, but the hinge press is not applied to the artificial menstrual blood absorption part.
The air-through manufacturing method is a method in which a fiber web is placed on a breathable net or drum and hot air is blown to heat-bond intersections of constituent fibers to form a nonwoven fabric. The air-through nonwoven fabric has a substantially flat surface, and the fiber density is substantially uniform throughout the nonwoven fabric.

FIG. 9 is a diagram showing the structure of the evaluation object (nonwoven fabric + absorbent) and the measurement result of the rewet rate. The rewetting rates of the following five types of evaluation objects were measured.
(1) Comparative example 1 = Comparative surface sheet a + absorber (2) Comparative example 2 = Comparative surface sheet a + Comparative second sheet c + absorber (3) Comparative example 3 = Comparative surface sheet a + Example second sheet d + absorber (4) Example 1 = Implementation surface sheet b + Absorber (5) Example 2 = Implementation surface sheet b + Implementation second sheet d + Absorber

When the rewetting rates of Comparative Example 1 and Example 1 are compared, Example 1 has a lower rewetting rate than Comparative Example 1 (−20.1%). That is, it can be said that the implementation surface sheet b (the nonwoven fabric 10 described above, FIG. 2A) is less likely to be rewet than the comparison surface sheet a. As can be seen from the table of FIG. 8, the implementation surface sheet b (convex part) is thicker than the comparison surface sheet a, and the absorber and the filter paper (actually skin) can be kept away. Because.
Further, the comparative surface sheet a has a planar shape, whereas the implementation surface sheet b has an uneven shape. Therefore, since the embodiment surface sheet b can reduce the contact area with the filter paper (skin) compared to the comparison surface sheet a, the rewetting rate of Example 1 is lower than that of Comparative Example 1. I can say that.

  Next, when the rewetting rates of Example 1 and Example 2 (or Comparative Example 1 and Comparative Example 2) are compared, Example 2 is more than Example 1 (Comparative Example 2 is more than Comparative Example 1). ) The rewet rate is low. That is, when the second sheet is provided between the top sheet and the absorbent body, the absorbent body and the filter paper (actually the skin) can be kept away, so it can be said that rewetting is difficult. However, as described in the second embodiment, from the viewpoint of preventing stuffiness, when the second sheet is provided, the absorbent body and the skin (moisture) are moved away from each other, so that the stuffiness is less than when the second sheet is not provided. It can be said that it is easy.

  Furthermore, when the rewetting rates of Comparative Example 2 and Comparative Example 3 are compared, Comparative Example 3 has a lower rewetting rate than Comparative Example 2. That is, the working second sheet d (FIG. 4B) in which the high density region and the low density region communicate with each other in the thickness direction is rewet than the comparative second sheet c in which the fiber density is substantially uniform in the entire area of the second sheet. It can be said that it is difficult. In this rewet evaluation method, in addition to the liquid returning from the absorber, the liquid remaining in the second sheet or the surface sheet is also returned to the surface sheet by pressure (weight) and absorbed by the filter paper. . That is, in the implementation second sheet d, as described above, the liquid can be reliably transferred to the absorber by the capillary force in the high density region, and it is difficult for the liquid to remain in the second sheet or the surface sheet. It can be said that the rewet rate could be reduced.

  By using this nonwoven fabric evaluation test, the nonwoven fabric obtained by air flow treatment (FIG. 3A) is used as the top sheet, not the nonwoven fabric by the air-through treatment, and the second sheet is used between the top sheet and the absorbent, so that the rewet rate It can be seen that can be reduced. Furthermore, the rewetting rate can be further reduced by using a non-woven fabric in which the high density region and the low density region communicate in the thickness direction as the second sheet.

=== Third Embodiment (Modification of Surface Sheet) ===
FIG. 10A is a diagram illustrating a top sheet 51 according to the third embodiment. In this surface sheet 51 (nonwoven fabric), the heights of the convex portions 6A and 6B adjacent in the width direction are different. In the case of such a surface sheet 51, the contact area between the user's skin and the surface sheet 51 can be reduced without reducing the number of convex portions. That is, the surface sheet 51 of the third embodiment can reduce the contact area between the skin and the surface sheet 51 without significantly reducing the strength.
In order to manufacture such a surface sheet 51, for example, each area (air volume) of the ejection ports 16 arranged in the CD direction shown in FIG. 3A may be changed.

=== Fourth Embodiment (Modification of Top Sheet) ===
FIG. 10B is a diagram illustrating a top sheet 52 according to the fourth embodiment. An opening 53 is provided in the concave portion 7 of the surface sheet 52. By this opening 53, the liquid that has entered the recess 7 can be transferred to the absorber 4 (second sheet 3) more quickly than the above-described top sheet 2. Also, a large amount of liquid or highly viscous liquid can be smoothly transferred to the absorber 4 through the opening 53.
However, since the opening 53 is provided in the recess 7, the strength is reduced as compared to the above-described topsheet 2.
Moreover, although the opening part 53 shown to FIG. 10B is a hole penetrated in the thickness direction, you may provide a hollow in the recessed part 7, and a liquid can be rapidly transferred to the absorber 4 also in this case. it can.
In order to manufacture the topsheet 52 having such an opening 53, for example, an air-impermeable plate or the like may be arranged on the air-permeable support member 12 at a constant interval in the MD direction (not shown). ). Since the fiber on the air-impermeable plate has a smaller fiber amount than other regions, all (or most of) the fiber on the plate is blown to the convex region by the fluid f, and the opening 53 is formed.

=== Other Embodiments ===
In the topsheet 2 of the above-described embodiment, the convex portions 6 are formed at equal intervals in the width direction. However, the present invention is not limited thereto, and the convex portions 6 may be formed at different intervals.

  In the above-described embodiment, the non-woven fabric in which the high-density region 31 and the low-density region 32 communicate with each other in the thickness direction is used as the second sheet 3, but is not limited thereto. For example, you may use the nonwoven fabric (comparison second sheet c) by an air through manufacturing method as the second sheet 3. FIG. However, it can be seen from the results of the rewetting evaluation test in FIG. 9 that the second working sheet d is less likely to rewet than the comparative second sheet c.

  In the absorbent body 4 of the above-described embodiment, the absorbent body material 43 outside the interspersed part 48 does not have a superabsorbent resin (SAP). However, the present invention is not limited to this, and the absorbent body material 43 has SAP. It is acceptable.

  As mentioned above, the above-mentioned embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

FIG. 1A is a top view of a sanitary napkin, and FIG. 1B is a cross-sectional view of the sanitary napkin. FIG. 2A is a top view of the nonwoven fabric, and FIG. 2B is an enlarged perspective view of the nonwoven fabric. FIG. 3A is a diagram illustrating a state in which a fluid is sprayed on a fiber web, and FIG. 3B is a diagram illustrating a nonwoven fabric manufacturing apparatus. 4A is a perspective view of the second sheet, and FIG. 4B is a cross-sectional view of the second sheet. 5A to 5D are diagrams showing a method for manufacturing a nonwoven fabric. FIG. 6A is a diagram illustrating a top view of the absorber, and FIG. 6B is a cross-sectional view of the dotted portion. 7A to 7D are diagrams showing the absorption behavior of the liquid excreted in the sanitary napkin. It is a table | surface explaining the constituent fiber of the nonwoven fabric used for evaluation. It is a figure which shows the structure of an evaluation target object, and the measurement result of a rewet rate. FIG. 10A is a diagram showing the top sheet of the third embodiment, and FIG. 10B is a diagram showing the top sheet of the fourth embodiment.

Explanation of symbols

1 sanitary napkin, 2 surface sheet, 3 second sheet, 3 'non-woven fabric,
4 Absorber, 5 Back sheet, 6 Convex part, 61 Center part, 62 Side part,
7 concave portion, 8 side sheet, 9 wing portion, 10 nonwoven fabric,
11 Fiber web, 12 Breathable support member, 13 Conveyor,
131 belt part, 14 spraying device, 15 spraying part,
16 outlet, 17 air intake, 18 heater, 31 high density area,
32 Low density area, 33 Breathable net, 35 Convex part, 36 Concave part,
41 bulge, 43 absorbent material,
44 absorbent fiber (pulp fiber), 45 super absorbent resin (SAP),
46 Embossing, 47 Deep groove part, 48 Dotted part, 50 Liquid 51 Top sheet of the third embodiment, 52 Top sheet of the fourth embodiment,
53 opening

Claims (5)

A liquid-permeable surface sheet;
An impervious back sheet,
An absorbent article having a liquid retaining absorbent disposed between the top sheet and the back sheet,
The surface sheet has a concave portion and a convex portion so that the surface has an uneven shape, and the concave portion has less basis weight than the convex portion,
The absorbent body is an absorbent article having interspersed portions where superabsorbent resins are densely packed ,
The absorbent has absorbent fibers;
The fiber density of the absorbent fiber in the interspersed part is lower than the fiber density of the absorbent fiber in the absorbent body outside the scattered part,
The absorbent article characterized in that the end portion in the longitudinal direction of the absorbent body has a higher content of the interspersed portion than the central portion of the absorbent body in the longitudinal direction . The absorbent article according to claim 1 ,
Between the absorber and the top sheet, a liquid-permeable second sheet,
The second sheet is a non-woven fabric, and has a high-density region having a fiber density higher than an average fiber density in the non-woven fabric, a low-density region having a fiber density lower than the average fiber density, and the high-density region and the The low density region communicates with the absorbent side from the top sheet side in the thickness direction of the nonwoven fabric. A liquid-permeable surface sheet;
  An impervious back sheet,
  An absorbent article having a liquid retaining absorbent disposed between the top sheet and the back sheet,
  The surface sheet has a concave portion and a convex portion so that the surface has an uneven shape, and the concave portion has less basis weight than the convex portion,
  The absorbent body is an absorbent article having interspersed portions where superabsorbent resins are densely packed,
  The absorbent has absorbent fibers;
  The fiber density of the absorbent fiber in the interspersed part is lower than the fiber density of the absorbent fiber in the absorbent body outside the scattered part,
  The absorbent sheet according to claim 1, wherein the top sheet is a non-woven fabric formed of a fiber assembly having a surface with irregularities formed by spraying a fluid.   A liquid-permeable surface sheet;
  An impervious back sheet,
  An absorbent article having a liquid retaining absorbent disposed between the top sheet and the back sheet,
  The surface sheet has a concave portion and a convex portion so that the surface has an uneven shape, and the concave portion has less basis weight than the convex portion,
  The absorbent body is an absorbent article having interspersed portions where superabsorbent resins are densely packed,
  The absorbent article characterized in that the end portion in the longitudinal direction of the absorbent body has a higher content of the interspersed portion than the central portion of the absorbent body in the longitudinal direction.   A liquid-permeable surface sheet;
  An impervious back sheet,
  An absorbent article having a liquid retaining absorbent disposed between the top sheet and the back sheet,
  The surface sheet has a concave portion and a convex portion so that the surface has an uneven shape, and the concave portion has less basis weight than the convex portion,
  The absorbent body is an absorbent article having interspersed portions where superabsorbent resins are densely packed,
  The absorbent sheet according to claim 1, wherein the top sheet is a non-woven fabric formed of a fiber assembly having a surface with irregularities formed by spraying a fluid.