JP6875806B2 - Absorbent article - Google Patents

Description

The present invention relates to absorbent articles.

Conventionally, from the viewpoint of improving the fit to the wearer's body, it is widely practiced to provide an absorbent article such as a sanitary napkin with a raised portion protruding toward the wearer's skin side. In such an absorbent article, it is common to provide a protrusion on a part of the absorbent core arranged inside.
Further, for various purposes, unevenness is also formed on the absorbent body of the absorbent article. For example, in Patent Document 1, from the viewpoint of achieving both flexibility and thinness, the first compression recess extending from the front surface side to the back surface side and extending to the absorption layer in the front-rear end region in the longitudinal direction and the front surface from the back surface side. Described is an absorbent article forming a second compression recess that is recessed towards the side and extends to the absorbing layer. Further, in Patent Document 2, from the viewpoint of reducing stuffiness and the like due to the absorbed liquid, the small absorption portion of the absorbent article provided with a plurality of small absorption portions in which the liquid absorption layer projects toward the non-skin facing surface side. It is described that a compression portion that is recessed from the non-skin facing surface side toward the skin facing surface side is provided. Further, in Patent Document 3, in order to improve absorption performance and fit while realizing weight reduction and low cost, a concave first embossing extending from an upper layer to a lower layer is provided in an absorption layer having an upper layer and a lower layer. It is described that the second embossing, which is shallower than the first embossing, is formed only in the lower layer protruding from the upper layer in the width direction.

Japanese Unexamined Patent Publication No. 2013-146405 Japanese Unexamined Patent Publication No. 2014-110887 Japanese Unexamined Patent Publication No. 2014-171573

By the way, menstrual blood, which is a liquid absorbed by a sanitary napkin, may have a low viscosity or a relatively high viscosity depending on the period during the menstrual period, individual differences, and the physical condition at that time. From the viewpoint of preventing inconveniences such as stickiness and itching due to moistening of the skin, in each case, the liquid excreted on the absorbent article is absorbed by the absorber so as to be isolated from the skin in the shortest possible time. However, in many conventional absorbent articles, even if a liquid having a low viscosity exhibits a high absorption performance, a liquid having a high viscosity does not exhibit a sufficient absorption performance.

The present invention relates to an absorbent article that exhibits good absorption performance even for excrement liquid having a relatively high viscosity.

The present invention includes a skin-side sheet forming a skin-facing surface, a non-skin-side sheet forming a non-skin facing surface, and an absorber including an absorbent core, and a front portion, an excretion portion facing portion, and a rear portion in the longitudinal direction. The absorbent core is located between a pair of lateral regions and the pair of lateral regions in the excretion portion facing portion, and has a basis weight larger than that of the respective lateral regions. It has a large central region, and the central region is located between a thick region thicker than each side region and the thick region and each side region, and is located in the thick region. It has a high-density region that is thinner and has a higher density than the other, and in the high-density region, from the skin-facing surface side or the non-skin-facing surface side, inward in the thickness direction of the absorbent core. A plurality of locally high-density portions recessed toward each other are formed at intervals from each other, and the local high-density portions provide an absorbent article having a higher density than other portions in the high-density region. It is a thing.

According to the present invention, there is provided an absorbable article which exhibits good absorption performance even for an excrement liquid having a relatively high viscosity and particularly has a small amount of liquid residue on the surface.

FIG. 1 is a partially cutaway perspective view of a sanitary napkin according to an embodiment of the present invention. FIG. 2A is a sectional view taken along line IIa-IIa of FIG. 1, and FIG. 2B is a sectional view taken along line IIb-IIb of FIG. FIG. 3 is a plan view of the absorbent core of the sanitary napkin shown in FIG. 1 as viewed from the skin-facing surface side. FIG. 4 is a plan view of the absorbent core of the sanitary napkin shown in FIG. 1 as viewed from the non-skin facing surface side. 5 (a) and 5 (b) are enlarged plan views showing an example of a preferable arrangement of the compression portion formed in the absorbent core. FIG. 6 is a schematic view showing a main part of a fiber stacking device preferably used for producing an absorbent core of the sanitary napkin shown in FIG. 7 (a) to 7 (c) are explanatory views of a method for producing an absorber of the sanitary napkin shown in FIG. 8 (a) and 8 (b) are explanatory views of the action and effect of the sanitary napkin shown in FIG. 9 (a) and 9 (b) are schematic views showing a cross section of the outer peripheral portion of the fiber stacking drum in the fiber stacking device shown in FIG. 6 along the drum circumferential direction. FIG. 10 is a diagram corresponding to FIG. 2A in another embodiment of the present invention.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings.
As shown in FIG. 1, the sanitary napkin 1 (hereinafter, also simply referred to as napkin 1), which is an embodiment of the absorbent article of the present invention, has a skin-side sheet 10 forming a skin-facing surface and a non-skin-facing surface. The non-skin side sheet 13 forming the above and the absorber 14 including the absorbent core 40 are provided. The absorber 14 is arranged between the skin side sheet 10 and the non-skin side sheet 13.
In an absorbent article such as a sanitary napkin, the skin facing surface P is a surface facing the wearer's skin side when worn, and the skin side sheet 10 described above forms the skin facing surface. Further, in an absorbent article such as a sanitary napkin, the non-skin facing surface Q is a surface facing the wearer's skin side opposite to the normal clothing side when worn, and the non-skin side sheet 13 described above is a surface. It forms the non-skin facing surface.
Further, the napkin 1 has a front portion A, an excretion portion facing portion B, and a rear portion C in the longitudinal direction X thereof. In an absorbent article such as a sanitary napkin, the longitudinal direction X is a direction that coincides with the front-back direction of the wearer when worn, and the width direction Y is orthogonal to the longitudinal direction X in a plan view of the absorbent article. It is the direction to do.

The napkin 1 has an absorbent main body 15 having a skin-side sheet 10, an absorbent core 40, and a non-skin-side sheet 13 laminated in the thickness direction at a central portion in the width direction Y, and has an excretory portion facing portion. A pair of wing portions 17 and 17 are formed on the left and right sides of the absorbent main body 15 in B, and a pair of rear flap portions 18 and 18 are formed on both left and right sides of the absorbent main body 15 in the rear portion C.
As shown in FIG. 1, the skin-side sheet 10 in the present embodiment includes a liquid-permeable surface sheet 11 and a pair of side sheets 12 and 12 joined to both sides thereof. The liquid-permeable surface sheet 11 is arranged at the center of the napkin 1 in the width direction Y so as to extend in the longitudinal direction X. The side sheets 12 are arranged on both sides of the napkin 1 in the longitudinal direction X, and as shown in FIG. 2A, each side sheet 12 is inside with a part of the inner edge portion 12a side overlapped on the surface sheet 11. It is joined to the surface sheet 11 at a position slightly outward from the edge portion 12a in the width direction Y. The pair of wing portions 17, 17 and the pair of rear flap portions 18, 18 are composed of a side sheet 12 extending from both side edges of the absorbent body 15 and a non-skin side sheet 13. On the surface of the wing portion 17 on the non-skin side sheet 13 side, a wing portion adhesive portion (not shown) for fixing to the non-skin facing surface of the crotch portion of the shorts is provided, and the non-skin facing portion of the absorbent body 15 is provided. The surface is provided with a main body adhesive portion (not shown) for fixing the absorbent main body 15 to the inner surface of the shorts. It is preferable that the surface of the rear flap portion 18 on the non-skin side sheet 13 side is also provided with an adhesive portion for fixing to the inner surface of the shorts.

The skin-side sheet 10 and the non-skin-side sheet 13 have a portion extending outward from the peripheral edge of the absorber 14 bonded to each other with an adhesive, and heat-sealed at the peripheral edge of the napkin 1 by heat sealing or the like. It is joined by.

As shown in FIGS. 1 and 3, the absorber 14 in the present embodiment includes a vertically elongated absorbent core 40 that is long in the same direction as the longitudinal direction X of the napkin 1. The absorbent core 40 is composed of a fiber aggregate made of a fiber material such as pulp fiber or a fiber aggregate in which a superabsorbent polymer is retained between the fibers of the fiber aggregate. Further, as shown in FIG. 1, the absorber 14 includes a core wrap sheet 14c that wraps the absorbent core 40. Specifically, the absorbent core 40 is covered with a core wrap sheet 14c made of tissue paper or a water-permeable non-woven fabric over both side edges in the longitudinal direction X and the entire upper and lower sides. The core wrap sheet 14c is used for the purpose of preventing leakage of the material forming the absorbent core 40 and improving the shape retention of the absorbent core 40. It is preferable that the absorbent core 40 is covered with one or a plurality of core wrap sheets over the entire circumference of the cross section along the width direction of the absorbent core 40. For example, both side portions of one core wrap sheet arranged on the skin-facing surface or the non-skin-facing surface side of the absorbent core 40 are folded back to the other surface side of the absorbent core 40, and the folded portion is folded back. It is also preferable that the core wrap sheets are laminated on both sides of another core wrap sheet covering the other surface. The sheets of the laminated portion may not be joined, but it is also preferable that the sheets are bonded.

Between the skin side sheet 10 and the absorber 14, between the absorbent core 40 and the core wrap sheet that covers the skin facing surface side, and the core wrap sheet that covers the absorbent core 40 and its non-skin facing surface side. The spaces may not be bonded to each other, but it is preferable that the spaces are bonded to each other by an adhesive patterned with an intermittent pattern such as a dot pattern, a spiral pattern, a stripe pattern, or a checkered pattern.
In the napkin 1 of the present embodiment, since the longitudinal direction and the width direction of the absorbent core 40 coincide with the longitudinal direction X and the width direction Y of the napkin 1 (absorbent article), the absorbent core 40 The longitudinal direction and the width direction are also expressed as the longitudinal direction X and the width direction Y. Further, although the core wrap sheet is not shown in FIGS. 2, 3, 5, 7, and 8, the core wrap sheet is together with the absorbent core 40 at the position of the compression portion 6 in these figures. , The absorber 14 is recessed from the skin-facing surface P side toward the non-skin facing surface Q side. It should be noted that FIGS. 2 (a) and 2 (b) are summarized, and FIGS. 2, 5 (a) and 5 (b) are summarized, and FIGS. 5 and 7 (a) to 7 (c) are summarized. 7, FIG. 8 (a) and FIG. 8 (b) are collectively referred to as FIG.

As shown in FIGS. 2 and 3, the absorbent core 40 is located between the pair of side regions 45 and 45 and the pair of side regions 45 and 45 in the excretion portion facing portion B, and each side region. It has a central region 41 having a basis weight larger than 45. As shown in FIG. 3, the central region 41 in the present embodiment is formed in an elliptical shape in a plan view, and is formed in the central portion of the absorbent core 40 in the width direction Y. As shown in FIG. 3, the central region 41 is preferably formed in a vertically long shape in which the length of the absorbent core 40 along the longitudinal direction X is longer than the length of the absorbent core 40 along the width direction Y.
The pair of lateral regions 45, 45 are formed on both sides of the absorbent core 40 in the longitudinal direction, respectively, extending in the longitudinal direction X of the absorbent core 40. As shown in FIG. 3, the lateral region 45 is formed so as to extend outward along each side edge 41S of both side edges 41S of the central region 41, and is formed inside along the side edge 41S of the central region 41. It has an edge 45a and a linear outer edge 45b that forms part of the side edge of the absorbent core 40. The plan view shape of the central region 41 may be an elliptical shape, a vertically long rectangular shape, an oval shape in which the central portion is constricted, or another shape such as a vertically long rectangular shape, a square shape, or a circular shape, instead of the elliptical shape. ..

Further, as shown in FIGS. 2 and 3, the central region 41 of the absorbent core 40 includes a thick region 42 thicker than each side region 45 and a thick region 42 in the width direction of the absorbent core 40. It is located between each side region 45 and has a high-density region 43 which is thinner and denser than the thick-walled region 42.

As shown in FIG. 2, the thick region 42 of the absorbent core 40 in the present embodiment forms a protruding portion 44 on the surface of the absorbent core 40 on the non-skin facing surface side. The protruding portion 44 is formed of a part of the thick region 42 in the thickness direction. Further, the protruding portion 44 including the thick-walled region 42 and a part of the thick-walled region 42 is formed in the central portion of the central region 41 in the width direction Y of the absorbent core 40, and is a plane of the absorbent core 40. Visually, it has a long shape in the longitudinal direction X of the absorbent core 40. Further, the high-density region 43 is formed on both sides of the central region 41 in the longitudinal direction, respectively, extending in the longitudinal direction X of the absorbent core 40, and has a long shape in the longitudinal direction X of the absorbent core 40. That is, in each of the thick-walled region 42, the protruding portion 44, and the high-density region 43 in the present embodiment, the length along the longitudinal direction X of the absorbent core 40 is longer than the length along the width direction Y of the absorbent core 40. It is formed in a long vertically long shape. In the high-density region 43, a pair of outer edges along the longitudinal direction of the absorbent core 40 are adjacent to the lateral region 45.

Further, the thick region 42, the protruding portion 44, and the high-density region 43 are all formed at least in the excretion portion facing portion B of the absorbent article such as the napkin 1. In the example shown in FIG. 1, it is formed from the vicinity of the front end portion of the excretion portion facing portion B to a part of the rear portion C. The thick region 42, the protrusion 44, and the high-density region 43 are all preferably formed over a length of 20% or more and 100% or less of the total length of the absorbent core 40 in the longitudinal direction X, and absorb. It is more preferable that the sex core 40 is formed over a length of 30% or more and 100% or less of the total length.

The absorbent article of the present invention is, for example, in the napkin 1 of the present embodiment or the napkin 1A of the second embodiment described later, in the high-density region 43 of the absorbent core 40 from the skin-facing surface P side or non-skin. A plurality of locally high-density portions 6 recessed inward in the thickness direction of the absorbent core 40 from the facing surface Q side are formed at intervals from each other.
As shown in FIGS. 2 and 3, the napkin 1 of the present embodiment has a local high density recessed in the high density region 43 of the absorbent core 40 from the skin facing surface P side toward the non-skin facing surface Q side. A plurality of compression portions 6 which are portions are formed in a scattered manner with a space between them.
Here, the compression portion is a local high-density portion in the present invention, and means a portion having a higher density than the surroundings in a plan view. That is, in the high-density region 43, the compression portion 6 as a local high-density portion having a higher density exists.
As shown in FIG. 5A, in the compression unit 6 of the present embodiment, the shape of each compression unit 6 is circular in the plan view of the absorbent core 40, and the plurality of compression units are arranged in a staggered pattern. It is formed by a pattern. More specifically, in the high-density region 43 and the adjacent lateral region 45, a longitudinal compression section row 6x in which the compression sections 6 are arranged in series at intervals in the longitudinal direction X of the absorbent core 40 absorbs. A plurality of rows are formed in the width direction Y of the sex core 40, and the positions of the compression portions 6 in the longitudinal direction X of the adjacent longitudinal compression portion rows 6x are shifted by a half pitch. FIG. 5B is a diagram showing another preferable example of the arrangement of the compression portions 6, wherein the compression portions 6 are arranged in series at intervals in the longitudinal direction X of the absorbent core 40 in the longitudinal direction compression section row 6x. Are formed in a plurality of rows in the lateral direction of the absorbent core 40, and the positions of the compression portions 6 in the longitudinal direction X of the adjacent longitudinal compression portion rows 6x are the same.
The individual shape of the compression unit 6 is preferably circular in a plan view, but may be a non-circular shape such as an ellipse, an oval, a square, a rectangle, or a triangle. As for the ellipse and the oval, the length of the major axis is preferably 3.0 times or less the length of the minor axis.

In each arrangement shown in FIGS. 5 (a) and 5 (b), the arrangement pitch P1 of the compression unit 6 in each longitudinal compression unit row 6x is preferably 110% with respect to the diameter L6 of the compression unit 6. As described above, it is more preferably 120% or more, preferably 350% or less, more preferably 340% or less, and preferably 110% or more and 350% or less, more preferably 120% or more and 340% or less. Further, the arrangement pitch P2 of the longitudinal compression section row 6x in the width direction Y of the absorbent core 40 is preferably 110% or more, more preferably 120% or more, and more preferably 120% or more with respect to the diameter L6 of the compression section 6. Is 350% or less, more preferably 340% or less, and preferably 110% or more and 350% or less, more preferably 120% or more and 340% or less. The diameter L6 of the compression portion 6 is preferably 1.0 mm or more, more preferably 1.5 mm or more, preferably 5.0 mm or less, more preferably 4.0 mm or less, and preferably 1. It is 0 mm or more and 5.0 mm or less, more preferably 1.5 mm or more and 4.0 mm or less.
When the compression portion 6 has a shape other than a circle, the longer length of the length X in the longitudinal direction and the length Y in the width direction of the compression portion 6 is set to the length of the above-mentioned "diameter". Read as. For example, in the case of an elliptical compression portion inclined with respect to the longitudinal direction X, the compression portion is divided into a longitudinal direction X component and a width direction Y component, and the respective lengths are the length and width of the longitudinal direction X component. Let the length of the direction Y component be the length, and the longer of them be the length of the "diameter". Further, the arrangement pitch P1 of the compression unit 6 in the longitudinal compression unit row 6x is the length between the center points of the longitudinal X component of the compression unit 6, and the arrangement pitch P2 of the compression unit 6 in the width direction Y is compression. Let it be the length between the center points of the Y component in the width direction of the part 6.

In the napkin 1 of the present embodiment, as shown in FIG. 3, the compression unit 6 is scattered in both the high-density region 43 and the lateral region 45 adjacent to the high-density region 43 in a similar pattern. Although it is formed, instead of this, the compression portion 6 may be formed only in the high-density region 43.
It is preferable that a plurality of compression portions having different arrangement positions in the width direction Y of the absorbent core 40 are formed in the high-density region 43. For example, two or more rows of the above-mentioned longitudinal compression portion rows 6x are formed. It is preferable to have.

The high-density region 43 in the absorbent core 40 of the napkin 1 of the present embodiment is the high-density region 43 as shown in FIG. 7 (a) by using the fiber stacking device 63 whose main part is shown in FIG. 7 (a). A fiber stack 40A having a thick, high-thickness, wide-thickness region 41'including the side portion 43'at the center of the width-direction CD orthogonal to the transport-direction MD at the time of manufacture [FIG. 7 (FIG. 7). a)] is manufactured, and then the fiber stack 40A is covered with a core wrap sheet (not shown), and the fiber stack 40A is widened by using the press device shown in FIG. 7 (b). It is formed by performing a press working to pressurize and compress the side portion 43'of the thick region 41'.
In the napkin 1 of the present embodiment, a pair of side portions 43'of the fiber stack 40A along the mechanical direction MD of the wide and thick region 41', which is elliptical in plan view, is shown in FIG. 7 (b). As described above, the thickness is reduced by being compressed by the pressurization by the press device, and the pressurized and compressed side portion 43'is compared with the thick region 42 which is not compressed or is relatively weakly compressed. It is a high-density region 43 having a high density.

As shown in FIG. 7C, the embossed roll 74 and the anvil roll 76 are formed in the high-density region 43 of the absorbent core 40 of the napkin 1 of the present embodiment and the lateral region 45 adjacent to the high-density region 43. The compression portion 6 described above is formed by embossing with an embossing device provided with. Therefore, in the high-density region 43 of the napkin 1 of the present embodiment, the portion where the compression portion 6 is formed is compressed by the embossing process, so that the compression portion 6 in the high-density region 43 is not formed. The density is higher than that of the portion, and in the side region 45, the portion where the compression portion 6 is formed is compressed by the embossing process, so that the compression portion 6 in the side region 45 is formed. The density is higher than that of the unfilled part.
The side region 45 of the absorbent core 40 of the napkin 1 of the present embodiment is not compressed by the pressing device or is compressed weakly as compared with the side portion 43'of the wide thick region 41'. The basis weight is lower than that of the high-density region 43 and the thick-walled region 42, and the density is lower than that of the high-density region 43.

The napkin 1 of the present embodiment is used by being fixed to the crotch portion of shorts in the same manner as a normal sanitary napkin.
When a liquid such as menstrual blood is discharged onto the surface sheet 11 of the excretion portion facing portion B of the napkin 1 while wearing the napkin 1, the liquid is tsubo as shown by an arrow a in FIG. 8 (a). It is absorbed by the large amount of the central region 41. Since the central region 41 has a high basis weight, it has a high absorption capacity and easily holds excrement. In addition to this, the presence of the thick region 42 of the central region 41 and the high-density region 43 adjacent thereto makes it easy for the liquid to be absorbed deep in the thickness direction, and a part of the liquid is transferred to the high-density region 43. The density gradient allows for better diffusion and retention of the liquid, which increases the rate of absorption of the liquid. For this reason, it is difficult for the liquid to remain on the skin-side sheet, and it is difficult for the liquid to return from the absorbent core 40 to the surface sheet 11, so that the wearer's skin does not feel wet with the liquid.
On the other hand, as shown in FIG. 8B, the compression portion 6 provided in the high-density region 43 is recessed from the skin-facing surface side toward the non-skin-facing surface side, and is a portion located around the skin in a plan view. Since the density is higher and the density of the high-density region 43 is increased on the skin contact surface side, even a highly viscous liquid flowing on the surface of the absorber 14 in the width direction Y is absorbed by the portion. It will be easier. Here, since the high-density region 43 is located adjacent to the thick-walled region 42, the liquid is easily held in the thick-walled region 42, and the high-density region 43 has a higher basis weight than the lateral region 45. The high-density region 43 tends to have a margin in the absorption capacity of the liquid. Therefore, even in the high-density region 43, the liquid is easily absorbed and held from the skin contact surface side, so that liquid leakage from the width direction is suppressed.
Due to such an action, according to the napkin 1 of the present embodiment, even in the case of a liquid having a relatively high viscosity as well as a liquid having a low viscosity, between the surface sheet 11 and the surface sheet 11 and the absorber 14. It is possible to suppress the retention of liquid in the skin, effectively suppress the occurrence of stickiness and discomfort due to the liquid reattaching to the skin, and it is induced by the skin becoming excessively moist. Itching of the skin can be effectively prevented. It also has excellent leak-proof performance.
Such an effect is more reliably achieved by forming the compression portions 6 in a scattered pattern in the high-density region 43.

Further, in the absorbent core 40 of the napkin 1 of the present embodiment, the lateral regions 45 and 45 and the central region 41 are integrally molded, so that the above-mentioned effect can be more reliably achieved without hindering the transferability of the liquid. To.
In the present specification, "integrally molded" means that the members manufactured in another process are formed as a continuous integral body, unlike the one in which the members are bonded to each other by a joining means such as an adhesive or compression. Means. Therefore, at the boundary between the central region 41 and the lateral regions 45 and 45, there are no adjacent portions or joint portions between the cores that occur when two separately manufactured absorbent cores are arranged side by side. Further, in the napkin 1 of the present embodiment, the entire absorbent core 40 is integrally molded, and the portion 52d forming the protruding portion 44 and the portion 52u closer to the skin side in the thick-walled region 42 described later. Similarly, there are no adjacent parts or joints between layers.

Further, in the napkin 1 of the present embodiment, since the compression portion 6 is formed not only on the high-density region 43 but also on the surface of the side region 45 on the skin-facing surface side, the compression portion 6 is formed on the surface sheet 11 overlapping the side region 45. The liquid discharged into the surface sheet 11 or the liquid flowing in the surface sheet 11 or between the surface sheet 11 and the absorber 14 and reaching the side region 45 has a relatively high viscosity. Is also smoothly absorbed by the lateral region 45 as indicated by the arrow d. As a result, the absorption performance for excrement liquid having a relatively high viscosity is further improved.

Further, in the napkin 1 of the present embodiment, as shown in FIG. 2A, the thick region 42 is thick because the protruding portion 44 is formed on the surface of the absorbent core 40 on the non-skin facing surface side. It is possible to improve the adhesion between the skin side sheet 10 and the absorber 14 while ensuring a high absorption capacity in the meat region 42. As a result, the absorption performance for excrement liquid having a relatively high viscosity is further improved.

From the viewpoint of ensuring that the above-mentioned one or more effects are more reliably achieved, the napkin 1 preferably has the following one or more configurations.
The basis weight of the central region 41 is preferably 1.2 times or more, more preferably 1.5 times or more, and preferably 3.5 times or less, more preferably more than the basis weight of the side region 45. Is 3.0 times or less, preferably 1.2 times or more and 3.5 times or less, and more preferably 1.5 times or more and 3.0 times or less. The same applies to the relationship between the basis weight of the thick region 42 and the basis weight of the lateral region 45.

Further, in the absorbent core 40, the thickness t3 of the high-density region 43 is preferably 80% or less, more preferably 75% or less, and preferably 35% or more of the thickness t1 of the thick-walled region 42. It is more preferably 40% or more, preferably 35% or more and 80% or less, and more preferably 40% or more and 75% or less. The thickness t3 of the high-density region 43 is the thickness of the portion where the compression portion 6 is not formed.
Further, in the absorbent core 40, the density of the high-density region 43 is preferably 1.2 times or more, more preferably 1.5 times or more, and preferably 3 times the density of the thick-walled region 42. It is 5.5 times or less, more preferably 3.25 times or less, preferably 1.2 times or more and 3.5 times or less, and more preferably 1.5 times or more and 3.25 times or less. On the other hand, in the absorbent core 40, it is preferable that the basis weight in the high-density region 43 is equivalent to the basis weight in the thick-walled region 42. The term "equivalent" here means that the basis weight of the high-density region 43 is 80% or more and 120% or less of the basis weight of the thick-walled region 42. The basis weight of the high-density region 43 is more preferably 90% or more and 110% or less of the basis weight of the thick-walled region 42 from the viewpoint of absorption capacity and reduction of discomfort in mounting.

Further, the density of the side region 45 may be higher or lower than the density of the thick region 42, or may be the same, but the density of the side region 45 is 20% of the density of the thick region 42. It is preferably 300% or more, and more preferably 30% or more and 200% or less of the density of the thick region 42.
Further, in the absorbent core 40, the thickness t5 of the side region 45 is preferably 75% or less, more preferably 70% or less, and preferably 30% or more of the thickness t1 of the thick region 42. It is more preferably 35% or more, preferably 30% or more and 75% or less, and more preferably 35% or more and 70% or less.
The thickness t1 of the thick region 42 is preferably 1.5 mm or more, more preferably 2.0 mm or more, preferably 8.5 mm or less, more preferably 8.0 mm or less, and preferably 1. It is 5.5 mm or more and 8.5 mm or less, more preferably 2.0 mm or more and 8.0 mm or less.

The area ratio of the compression portion 6 formed in the high-density region 43 is preferably 6% or more, more preferably 8% or more, and preferably 25% or less, more preferably 20% or less. It is preferably 6% or more and 25% or less, and more preferably 8% or more and 20% or less.
The area ratio of the compression portion 6 formed in the high-density region 43 is the ratio of the total area of the compression portion to the area of the surface of the high-density region 43 on the skin-facing surface side. A measurement piece having a length of 50 mm in the longitudinal direction X and a length of 7.5 mm in the width direction of the article is cut out, and the total area of the compression portions existing on the surface of the measurement piece on the skin-facing surface side is the total area of the measurement piece. The value obtained by dividing by the total area of the surface facing the skin is shown as a 100% ratio.

The area ratio of the compression portion 6 formed in the side region 45 is preferably 6% or more, more preferably 8% or more, and preferably 25% or less, more preferably 20% or less. It is preferably 6% or more and 25% or less, and more preferably 8% or more and 20% or less.
The area ratio of the compression portion 6 formed in the side region 45 is the ratio of the total area of the compression portion to the area of the surface of the side region 45 facing the skin, and from the side region 45, the article A measurement piece having a length of 30 mm in the longitudinal direction X and a length of 30 mm in the width direction Y of the article is cut out, and the total area of the compression portions existing on the surface of the measurement piece on the skin-facing surface side is the skin-facing surface of the measurement piece. The value divided by the total area of the surface on the surface side is shown as a 100% ratio.

The thickness t6 of the portion of the high-density region 43 where the compression portion 6 is formed is preferably 90% or less of the thickness t3 of the high-density region 43, that is, the thickness t3 of the portion where the compression portion 6 is not formed. , More preferably 85% or less, preferably 35% or more, more preferably 40% or more, and preferably 35% or more and 90% or less, more preferably 40% or more and 85% or less.
The thickness of the portion of the side region 45 where the compression portion 6 is formed is 80% or less of the thickness of the side region 45, that is, the thickness of the portion of the side region 45 where the compression portion 6 is not formed. Is preferable, more preferably 75% or less, preferably 10% or more, more preferably 20% or more, and preferably 10% or more and 80% or less, more preferably 20% or more and 75% or less.

The thickness of each part of the absorbent core 40 is such that the absorbent core 40 or the absorber 14 including the absorbent core 40 is cut along the width direction of the absorbent core 40 using a razor blade, and the cut absorption thereof is performed. A cross section of the sex core 40 ^{is subjected to a load of 0.5 gf / cm 2} , for example, a microscope (
Using a KEYENCE VHX-1000), the measurement is performed at a magnification of 20 to 100 times.
The thickness of each part of the absorbent core 40 and the width of each part described later are at the central position (IIa in FIGS. 3 and 4) that bisects the length of the absorbent core 40 in the thick region 42 along the longitudinal direction X. Measure at the indicated position), and if there are lateral grooves 51 and 56 described later at the center position, measure at a position where there is no lateral groove shifted back and forth. The density of each part is calculated from the thickness obtained by observing the cross section of the absorbent core 40 and the basis weight of the measuring piece cut out so as to include the entire thickness direction of the absorbent core. If there are lateral grooves 51 or 56 formed by reducing the material for forming the absorbent core, the measuring piece is cut out so as not to include them.

Further, in the width W1 of the central region 41 [see FIG. 2A], the ratio of the absorbent core 40 to the total width W is preferably 20% or more, more preferably 30% or more, and preferably 95% or less. , More preferably 90% or less, preferably 20% or more and 95% or less, and more preferably 30% or more and 90% or less.

In the width W2 of the thick region 42 and the protrusion 44 [see FIG. 2A], the ratio of the central region 41 to the width W1 is preferably 10% or more, more preferably 15% or more, respectively. It is preferably 80% or less, more preferably 75% or less, and preferably 10% or more and 80% or less, more preferably 15% or more and 75% or less. The width W2 of the thick region 42 or the protrusion 44 [see FIG. 2A] is preferably 10 mm or more, more preferably 15 mm or more, and preferably 60 mm or less, more preferably 50 mm or less, respectively. Further, it is preferably 10 mm or more and 60 mm or less, and more preferably 15 mm or more and 50 mm or less.

In the width W3 of the high-density region 43 [see FIG. 2A], the ratio of the central region 41 to the width W1 is preferably 2.5% or more, more preferably 5.0% or more, and preferably 5.0% or more. It is 35% or less, more preferably 30% or less, and preferably 2.5% or more and 35% or less, more preferably 5.0% or more and 30% or less. The width W3 of the high-density region 43 [see FIG. 2A] is preferably 2 mm or more, more preferably 5 mm or more, preferably 20 mm or less, more preferably 15 mm or less, and preferably 2 mm. It is 20 mm or more, and more preferably 5 mm or more and 15 mm or less. Within this range, it is easy to achieve both a sufficient amount of absorption in the high-density region 43 and a good fit of the absorbent article.

As shown in FIG. 4, the absorbent core 40 in the present embodiment has a vertical groove 50 extending along the longitudinal direction X of the absorbent core 40 and the absorbent core 40 on the non-skin facing surface side in the thick region 42. A lateral groove 51 extending along the width direction Y is formed, and a vertical groove 55 extending along the longitudinal direction X of the absorbent core 40 and an absorbent core are also formed on the non-skin facing surface side in each lateral region 45. A lateral groove 56 extending along the width direction Y of 40 is formed.

As shown in FIG. 2, the vertical groove 50 and the horizontal groove 51 of the thick region 42 are formed in the thick region 42 by the high basis weight portion 52 and the absorbent core having a relatively large basis weight of the material for forming the absorbent core. It is formed by forming a low basis weight portion 53 having a relatively small basis weight, and the vertical groove 50 and the horizontal groove 51 are each formed on the low basis weight portion 53. In the high basis weight portion 52 and the low basis weight portion 53 of the thick area 42, the density of the high basis weight portion 52 may be lower than the density of the low basis weight portion 53, or may be the same, but high. It is preferable that the density of the basis weight portion 52 is higher than the density of the low basis weight portion 53.

As shown in FIG. 2, the vertical groove 55 and the horizontal groove 56 of the lateral region 45 are formed in the lateral region 45 by the high basis weight portion 57 and the absorbent core having a relatively large basis weight of the material for forming the absorbent core. It is formed by forming a low basis weight portion 58 having a relatively small basis weight, and the vertical groove 55 and the horizontal groove 56 are each formed on the low basis weight portion 58. In the high basis weight portion 57 and the low basis weight portion 58 of the lateral region 45, the density of the high basis weight portion 57 may be lower than the density of the low basis weight portion 58, or may be the same, but high. It is preferable that the density of the basis weight portion 57 is higher than the density of the low basis weight portion 58.

If the vertical grooves 50 and 55 extending along the longitudinal direction X of the absorbent core 40 are formed on the non-skin facing surface Q side in the thick region 42 and the lateral region 45, the bending may be hindered when the napkin is worn. However, there are advantages such as being easy to follow the wearer's body shape.
Further, when the lateral grooves 51 and 56 extending along the width direction Y of the absorbent core 40 are formed on the non-skin facing surface Q side in the thick region 42 and the lateral region 45, the lateral grooves 51 and 56 are formed in accordance with the movement of the wearer. Since it is excellent in deformability, it has advantages such as less wrinkles and less discomfort in wearing.
Further, when the vertical grooves 50, 55 or the horizontal grooves 51, 56 are formed in the absorbent core 40, the liquid excreted in the groove space can be quickly taken into the absorbent core 40, so that the liquid has a high viscosity. Even if it can be absorbed more quickly. Further, since the taken-in liquid is easily diffused through the groove, the central portion of the absorbent core is less likely to accumulate, and even a highly viscous liquid is less likely to remain on the surface sheet 11. Increase.

The absorbent core 40 of the napkin 1 described above has, for example, a stacking fiber drum 64 having an accumulation recess 65 on the outer peripheral surface and rotating in one direction R, and a material for forming the absorbent core on the outer peripheral surface of the stacking fiber drum 64. After manufacturing the above-mentioned fiber stack 40A by using the fiber stacking device 63 (see FIG. 6) provided with a duct 69 for supplying the above-mentioned fibers in a scattered state, the press working and the above-mentioned press working shown in FIG. 7 (b) and FIG. 7 It can be manufactured by performing the embossing process shown in (c). More specifically, the example shown in FIGS. 7 (a) to 7 (c) will be described in a more specific manner. As shown in FIGS. 7 (a) and 7 (b), the width is widened by introducing the press roll 71 having a recess 72 in a part of the peripheral surface and the flat roll 73 having a smooth peripheral surface. After strongly pressing the side portion 43'of the meat region 41'to form the fiber stack 40A having the high density region 43, the fiber stack 40A is embossed as shown in FIG. 7 (c). By introducing the embossing roll 74 having the convex portion 75 for embossing in the above and the anvil roll 76 having the concave portion 77 in a part of the peripheral surface, the high-density region 43 and the side of the fiber stack 40A are formed. A large number of compression portions 6 are formed in the square region 45 in the pattern shown in FIG.

The embossing process for forming the compression portion 6 may be an embossing process in which only the work piece is pressurized without heating the embossed roll and the anvil roll, or one or both of the embossed roll and the anvil roll. May be embossed by heating and heating and pressurizing.
Similarly, the press working for forming the high-density region 43 may be a press working in which only the pressurizing of the work piece is performed without heating the press roll and the flat roll, or the press roll and the flat roll. Press working may be performed in which one or both are heated to heat and pressurize.
Further, FIGS. 7 (b) and 7 (c) show a case where the portion of the thick region 42 forming the protruding portion 44 is not pressurized, but the portion and the side of the thick region 42 are formed. One or both of the portions that become the square region 45 may be pressure-compressed weaker than the side portion 43'that becomes the high-density region 43.

A plurality of accumulation recesses 65 in the fiber stacking device 63 shown in FIG. 6 are formed at regular intervals in the circumferential direction of the outer peripheral surface of the fiber stacking drum 64. The bottom surface 66 of the accumulation recess 65 is made of a mesh plate or the like, and has a large number of pores that function as suction holes.
As shown in FIG. 9A, a recess 66a for forming a wide thick wall region 41'is formed in a part of the bottom surface 66 of the accumulation recess 65. At the bottom of the integration recess 65, poorly breathable members 67, 68 for forming low basis weight portions such as low basis weight portions 53, 58 are arranged. The non-breathable members 67 and 68 are fixed so as to project from the bottom surface of the accumulation recess 65, and may be a non-breathable member, for example, made of metal or plastic.
Similar to a known fiber stacking device equipped with a fiber stacking drum, the material 40'for forming an absorbent core is supplied into the duct while being sucked from the bottom surface of the accumulation recess 65, as shown in FIG. 9 (b). As described above, the material 40'for forming the absorbent core is deposited in the accumulation recess 65 in a predetermined shape. The fiber stack 40A is obtained by releasing the deposit 4'from the accumulation recess 65. As shown in FIG. 9B, the portion made of the core forming material deposited on the poorly breathable members 67 and 68 becomes the low basis weight portion 53 and the like, and is deposited on the bottom surface having no poorly breathable members 67 and 68. The portion is the high basis weight portion 52 and the like. The fiber stack 40A is subjected to press working as shown in FIG. 7 (b) and embossing as shown in FIG. 7 (c) before or after coating with the core wrap sheet, preferably after coating.

In the above-described embodiment, the manufacturing steps in which FIGS. 7 (b) and 7 (c) are performed in this order are shown, but the step of forming the high-density region 43 and the step of forming the compression portion 6 may be performed at the same time. Alternatively, the step of forming the high-density region 43 may be performed after the compression portion 6 is formed.

As the absorber 14, various substances conventionally used as absorbers for absorbent articles can be used without particular limitation, but like the absorber 14 of the napkin 1 described above, the absorbent core 40 and the absorbent core 40 can be used. It is preferably composed of a core wrap sheet 14c that encloses the absorbent core.
The absorbent core 40 and the triple product 40A used for producing the same may be a triple product of liquid-absorbent fibers such as pulp fibers, or a mixed product of the liquid-absorbent fibers and a water-absorbent polymer. It may be. Examples of the liquid-absorbent fiber constituting the absorbent core include cell roll-based hydrophilic fibers such as pulp fiber, rayon fiber, cotton fiber and cellulose acetate. These fibers may be used alone or in combination of two or more. In addition to cellulosic hydrophilic fibers, polyolefin fibers such as polyethylene and polypropylene, and condensed fibers such as polyester and polyamide may be included. Examples of the water-absorbent polymer include sodium polyacrylate, (acrylic acid-vinyl alcohol) copolymer, sodium polyacrylate crosslinked polymer, (dempun-acrylic acid) graft copolymer, and (isobutylene-maleic anhydride). Examples thereof include a polymer and a saponified product thereof, and polyaspartic acid. The fiber and the water-absorbent polymer can be used alone or in combination of two or more.

The absorbent core 40 is preferably entirely or partially made of pulp fibers, and the ratio of the pulp fibers to the total fibers contained in the absorbent core 40 is preferably 50 to 100% by mass, more preferably 80 to 80 to 100% by mass. It is 100% by mass, more preferably 100% by mass. In addition to the super absorbent polymer, a deodorant, an antibacterial agent, or the like may be added to the absorbent core as needed. Further, the absorber 14 may be composed of only the absorbent core 40.

As the core wrap sheet, a water-permeable fiber sheet such as tissue paper or non-woven fabric is preferably used. The core wrap sheet may wrap the entire absorbent core with one sheet, or may wrap the entire absorbent core with two or more core wrap sheets, for example, the skin of the absorbent core. The facing surface side and the non-skin facing surface side may be covered with separate sheets.
When the absorber 14 is composed of the absorbent core 40 and the core wrap sheet 14c that wraps the absorbent core, the compression portion 6 described above may be provided only on the absorbent core, but the core wrap It is preferable to provide the sheet and the absorbent core integrally.

As the surface sheet 11, the side sheet 12, and the non-skin side sheet 13, the same ones as those conventionally used in the art can be used without particular limitation. For example, as the surface sheet 11, a non-woven fabric having liquid permeability or a perforated film can be used. As the side sheet 12, a water-repellent non-woven fabric having high water pressure resistance, for example, a spunbond-melt blown-spanbond laminated non-woven fabric or the like can be used. As the non-skin side sheet 13, a liquid-impermeable film made of synthetic resin or a water-repellent non-woven fabric having high water pressure resistance such as spunbond-melt blown-spunbond laminated non-woven fabric can be used.

Next, the napkin 1A as the second embodiment will be described. Regarding the napkin 1A of the second embodiment, only the part different from the napkin 1 of the above-described embodiment will be described, and the other parts will be designated by the same reference numerals and the description thereof will be omitted. The above-mentioned description of the napkin 1 is appropriately applied to points not particularly described.

In the napkin 1A of the second embodiment, as shown in FIG. 10, the compression portion 6A, which is a locally high-density portion, is recessed from the non-skin facing surface side toward the skin facing surface side with respect to the absorbent core 40. The point that it has a shape is different from the above-mentioned napkin 1. In the napkin 1A, the compression portion 6A, which is a locally high-density portion, is formed so as to have an opening on the surface of the absorbent core 40 on the non-skin facing surface P side. The density is higher than that of the portion located around the compression portion 6A, and the density of the high-density region 43A is increased. The napkin 1A of the second embodiment is similar to the napkin 1 described above. The effect is played.

Although the present invention has been described above based on the preferred embodiment, the present invention is not limited to the above embodiment.
For example, the compression portion 6 may be formed only in the high-density region 43 and may not be formed in the side region 45. Further, in the absorbent core 40 shown in FIG. 3, a rectangular region 6N in which the compression portion 6 is not formed is formed in the central portion in the width direction Y, and the region 6N is a part of the front portion A. A region 6N extending from the rear portion to a part of the rear portion but not forming the compression portion 6 may be present over the entire length of the absorbent core 40 in the longitudinal direction X. The thick region 42 may be have a protrusion protruding on the skin facing side.

In addition to sanitary napkins, the absorbent articles of the present invention may be other absorbent articles such as panty liners (pantyliners), incontinence pads, and disposable diapers.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to such Examples.
[Example 1]
[Manufacturing of absorber]
Using the triple product apparatus shown in FIG. 6, the pulp fibers and the water-absorbent polymer were supplied to the triple product drum in a scattered state to produce a mixed triple product 40A having a wide thick region 41'. Next, this is covered with a core wrap sheet made of absorbent paper having a basis weight of 16 g / m ² , and then press working as shown in FIG. 7 (b) and embossing as shown in FIG. 7 (c). This was performed to obtain an absorber 14 having the shape shown in FIG. The absorbent core of the absorbent body 14, the portion disposed in the excretion portion facing section, the central region 41 and lateral region 45 having a basis weight of 200 g / m ² of basis weight 400 g / m ² is formed, the In the central region 41, a thick region 42 having a width W2 of 20 mm and a pair of high-density regions 43 having a width W3 of 10 mm were formed. The width W1 of the central region 41 and the width of each side region 45, which are lengths along the width direction Y of the absorbent core 40, were set to 40 mm and 27 mm.
On the surface of the high-density region 43 and the side region 45 on the skin-facing surface side, a compression portion 6 in which the core wrap sheet and the absorbent core are integrally recessed is arranged as shown in FIGS. 3 and 5 (a). Formed. The dimensions L6, P1 and P2 shown in FIG. 5A are 2.0 mm, 3.5 mm and 3.5 mm, respectively.

[Manufacturing of surface sheet]
Using the core-sheath fiber-shaped composite fiber [NBF (SH) (trade name) 2.3 dtex x 51 mm] of Daiwa Spinning Co., Ltd. as a raw material, ^{a card web with a basis weight of 25 g / m 2} is manufactured by the card method and 136 ° C. ± 5 The surface sheet 11 was prepared by passing hot air at ° C. for 5 to 10 seconds.

[Manufacturing of sanitary napkins]
The absorber produced as described above was arranged between the surface sheet 11 produced as described above and the non-skin side sheet made of a polyethylene resin film to obtain a sanitary napkin for testing. The surface sheet was fixed on the absorber by applying an adhesive in a spiral pattern on the absorber.

[Comparative Example 1]
A sanitary napkin for testing was obtained in the same manner as in Example 1 except that the absorber was not embossed as shown in FIG. 7 (c).

[Performance evaluation]
For the sanitary napkins of Example 1 and Comparative Example 1, the amount of surface liquid return was measured by the following method, and the surface liquid return property was evaluated. The results are shown in Table 1 below.

〔Measuring method〕
The sanitary napkins of Example 1 and Comparative Example 1 were placed horizontally so that the surface sheet side was on the upper side, and a cylindrical acrylic plate with an injection port having a diameter of 1 cm was placed on the bottom, and defibered horse blood was removed from the injection port. 6 g and 9 g were injected, respectively, and the state was maintained for 1 minute after the injection. Next, the acrylic plate with a cylinder was removed, and 16 sheets of absorbent paper (commercially available tissue paper) measuring 6 cm in length × 9.5 cm in width and having a basis weight of 13 g / m ^{2 were placed on the surface of the surface sheet.} Further, a weight was placed on the weight so that the pressure became 4.0 × 10 ^{2 Pa, and the pressure was applied for 5 seconds.} After pressurization, the absorbent paper was taken out, the weight of the paper before and after pressurization was measured, and the mass of the defibered horse blood absorbed by the paper was measured and used as the amount of surface liquid returned.
As the defibered horse blood, the following low-viscosity solution and high-viscosity solution whose viscosity was adjusted using defibered horse blood (manufactured by Nippon Biotest Research Institute Co., Ltd.) were used. The low-viscosity liquid assumed normal-viscosity menstrual blood, and the high-viscosity liquid assumed high-viscosity menstrual blood found in the first half of menstruation.
Low viscosity liquid: viscosity 8cP
High viscosity liquid: Viscosity 25 cP

According to the results in Table 1, when a low-viscosity liquid was used as the defibrotic horse blood, the sanitary napkin of Example 1 had a low surface liquid return amount and was excellent, similar to the sanitary napkin of Comparative Example 1. It showed the ability to prevent liquid from returning to the skin. Further, when a high-viscosity liquid was used as the defibered horse blood, the sanitary napkin of Example 1 had a significantly lower surface liquid return amount than the sanitary napkin of Comparative Example 1, and was used as an absorbent article of the present invention. According to this, it can be seen that excellent absorption performance, particularly excellent liquid return prevention property, can be obtained even for excrement liquid having a relatively high viscosity.

1 Sanitary napkin (absorbent article)
10 Skin side sheet 11 Surface sheet 12 Side sheet 13 Non-skin side sheet 14 Absorbent 14c Core wrap sheet 40 Absorbent core 41 Central area 42 Thick area 43 High density area 44 Overhang 40A Fiber fiber 41'Wide thick area 6 Compressed part (local high density part)
15 Absorbent body 17 Wing part 18 Rear flap part 50 Vertical groove in thick area 51 Horizontal groove in central area 55 Vertical groove in lateral area 56 Horizontal groove in lateral area

Claims (7)

It is provided with a skin-side sheet forming a skin-facing surface, a non-skin-side sheet forming a non-skin facing surface, and an absorbent body including an absorbent core, and has an absorbent front portion, an excretory portion facing portion, and a rear portion in the longitudinal direction. It ’s an article,
The absorbent core has a pair of lateral regions and a central region located between the pair of lateral regions and having a larger basis weight than the respective lateral regions in the excretion portion facing portion. ,
The central region is located between a thick region thicker than each of the lateral regions and between the thick region and each of the lateral regions, and is thinner and denser than the thick region. Has a density region and
The thick region forms a protrusion on the surface of the absorbent core on the non-skin facing surface side.
Local high-density portions recessed in the high-density region from the skin-facing surface side or the non-skin-facing surface side toward the inside in the thickness direction of the absorbent core are provided with a gap between them. A plurality of them are formed, and the local high-density portion has a higher density than other portions in the high-density region.
The local high-density portion is formed in a scattered spot shape.
An absorbent article in which the high-density region and the local high-density portion are formed only in the absorber. The absorbent article according to claim 1, wherein the local high-density portion is recessed from the skin-facing surface side of the absorbent core toward the non-skin-facing surface side. The absorbent article according to claim 1, wherein the local high-density portion is recessed from the non-skin facing surface side of the absorbent core toward the skin facing surface side. The absorbent article according to any one of claims 1 to 3 , wherein the absorbent core is integrally molded with the lateral region and the central region. Claims 1 to 4 , wherein a plurality of locally high-density portions recessed from the skin-facing surface side toward the non-skin-facing surface side are also formed in the lateral region at intervals from each other. The absorbent article according to any one item. The one according to any one of claims 1 to 5 , wherein a vertical groove extending along the longitudinal direction of the absorbent core is formed on the non-skin facing surface side in the thick-walled region and the lateral region. Absorbent article. The absorption according to any one of claims 1 to 6 , wherein lateral grooves extending along the width direction of the absorbent core are formed on the non-skin facing surface side in the thick region and the lateral region. Sex goods.

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