JP6388619B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as disposable diapers and sanitary napkins.

  Conventionally, in absorbent articles such as disposable diapers and sanitary napkins, an absorbent body in which an absorbent core composed of hydrophilic fibers such as wood pulp fibers and superabsorbent polymer particles dispersed in the hydrophilic fibers is covered with a core wrap sheet. Is used. Patent Document 1 discloses an absorbent body using a core wrap sheet having pulp as a main component and having irregularities with a predetermined height difference on the surface in order to improve the liquid absorption speed of the absorbent body and reduce the liquid return amount. Proposed.

JP 2014-158527 A

  In order to improve the wearing feeling of the absorbent article by improving the flexibility of the absorbent body, while containing the wood pulp fiber content of the absorbent core contained in the absorbent body, the content of the super absorbent polymer (SAP) Attempts have been made to make the absorbent core thin without increasing the rate and reducing the absorbent capacity of the absorbent core. However, generally, when the wood pulp fiber content of the absorbent core decreases, the absorption rate of the absorbent body tends to decrease. Further, when the content of the superabsorbent polymer particles in the absorbent core is increased and the content of the wood pulp fiber is decreased, the number of entangled wood pulp fibers is decreased, and the strength of the absorbent core is easily lowered. In addition, in an absorbent body using a wood pulp fiber-based core wrap sheet as the core wrap sheet, the SAP particles are swollen by absorbing body fluid, and the wood pulp fiber-based core wrap sheet is easily broken. As a countermeasure, nonwoven fabrics using thermoplastic synthetic fibers that do not decrease sheet strength even when wet as core wrap sheets are also used, but there is a limit to reducing the amount of wood pulp fibers used due to lack of water absorption. It was. In addition, when a wood pulp fiber web with an irregular shape is used as a core wrap sheet to improve the absorption rate, the core wrap sheet is repeatedly exposed to a large amount of body fluid such as urine to absorb the large amount of body fluid. The shape is irreversibly lost and the bulk is reduced. Furthermore, if a paper strength enhancer is added to the core wrap sheet or the core wrap sheet is densified in order to increase the strength of the core wrap sheet, the water absorption of the absorbent body decreases. Therefore, when using a wood pulp fiber web with a concavo-convex shape and a core wrap sheet, the liquid absorption rate of the absorber is improved and the desired effect of the concavo-convex is achieved, which is to reduce the liquid return amount. It was difficult. In addition, when the core wrap sheet repeatedly absorbs a large amount of body fluid, the core wrap sheet is broken due to a decrease in the strength of the core wrap sheet, and the highly absorbent polymer particles swollen by the absorbent core covered with the core wrap sheet are absorbed by the core wrap sheet. There is a risk of leaking outside.

  Therefore, an object of the present invention is to provide an absorbent article that can maintain liquid absorbency at a high level even when body fluid such as urine is repeatedly absorbed.

  As a result of intensive studies on the above problems, the present inventors have included 50% by mass or more of thermoplastic synthetic fiber as a core wrap sheet, and at least a part of a region between the absorbent core and the liquid-impermeable back sheet has a predetermined value. When the sheet | seat which has an uneven | corrugated pattern shape was used, even when the absorber absorbed body fluids, such as urine, repeatedly, the core wrap sheet | seat was hard to tear and the knowledge that liquid absorptivity became difficult to fall was acquired.

The present invention has been made based on the above knowledge, and includes an absorbent article including a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber disposed between the top sheet and the back sheet. The absorbent body has an upper surface and a lower surface, and includes an absorbent core having a longitudinal direction, a short side direction, and a thickness direction, and a core wrap sheet covering the lower surface of the absorbent core,
The core wrap sheet includes 50% by mass or more of thermoplastic synthetic fiber, has a first surface and a second surface opposite to the first surface, and the core wrap sheet further includes a length of the absorbent core. A first direction parallel to the direction, a thickness direction, and a second direction orthogonal to both the first direction and the thickness direction,
The first surface of the core wrap sheet has a region in contact with the lower surface of the absorbent core, and at least part of the region has a plurality of flanges protruding from the second surface toward the first surface, A plurality of grooves recessed in the direction from the first surface to the second surface, and the plurality of flanges and the plurality of grooves extend in the first direction and are alternately provided at predetermined intervals in the second direction. An absorbent article is provided.

The present invention includes the following aspects.
[Aspect 1]
An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet, the absorbent body having an upper surface and a lower surface An absorbent core having a longitudinal direction, a lateral direction and a thickness direction, and a core wrap sheet covering at least the lower surface of the absorbent core,
The core wrap sheet includes 50% by mass or more of thermoplastic synthetic fiber, has a first surface and a second surface opposite to the first surface, and the core wrap sheet further includes a length of the absorbent core. A first direction parallel to the direction, a thickness direction, and a second direction orthogonal to both the first direction and the thickness direction,
The first surface of the core wrap sheet has a region in contact with the lower surface of the absorbent core, and at least part of the region has a plurality of flanges protruding from the second surface toward the first surface, A plurality of grooves recessed in the direction from the first surface to the second surface, the plurality of flange portions and the plurality of groove portions extending in the first direction and provided alternately at predetermined intervals in the second direction. Absorbent article.
In the above aspect 1, a recoverable liquid transport channel is secured between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid-impermeable back sheet, and even when a large amount of body fluid is absorbed at once, a large amount Even when urine is absorbed, the strength is not easily lowered, and a high absorption rate and excellent diffusivity can be exhibited. Since the plurality of flanges and the plurality of grooves extend in the first direction parallel to the longitudinal direction of the absorbent core, diffusion of body fluid in the first direction can be promoted, and the absorption speed can be increased. Further, the core wrap sheet is provided with a plurality of flanges and a plurality of grooves as described above, thereby improving the flexibility and stretchability of the core wrap sheet, and the core wrap sheet follows the movement of the wearer. It can deform | transform and can improve the wearing feeling of an absorbent article.

[Aspect 2]
Each groove portion of the first surface of the core wrap sheet has a first bottom portion, and further provided on the first bottom portion discontinuously with respect to the first direction, and from the first surface to the second surface. The absorbent article of the said aspect 1 provided with the some recessed part dented toward the direction.
In the said aspect 2, when a core wrap sheet is seen from the 1st surface side, since the core wrap sheet is dented in two steps, the bulk recovery property of the thickness direction of a core wrap sheet can be improved more, and a high absorption rate And excellent diffusivity can be maintained.

[Aspect 3]
The absorbent article according to aspect 2, wherein the concave portion has a peripheral wall portion and a second bottom portion, and includes a hole portion that communicates with the second surface of the core wrap sheet in at least a part of the peripheral wall portion.
In the above aspect 3, since there is a hole communicating with the second surface of the core wrap sheet in at least a part of the peripheral wall portion, the liquid permeability to the back sheet side is excellent and the liquid diffusibility between the core wrap and the back sheet is improved. And the absorption rate can be increased.

[Aspect 4]
The absorbent article according to any one of the above aspects 1 to 3, wherein the absorbent core has one or more main grooves extending in the longitudinal direction on the lower surface side.
In the said aspect 4, since a space can be ensured between an absorption core and a core wrap sheet | seat by the main groove part of the lower surface side of an absorption core, it can be made to spread | diffuse while storing temporarily, Therefore And the absorbed liquid is more difficult to return (ie, better rewetting).

[Aspect 5]
The absorbent article according to aspect 4, wherein the absorbent core has one or more secondary groove portions that intersect the groove portions on the lower surface side.
In aspect 5 described above, the space formed between the absorbent core and the core wrap sheet is increased by the secondary groove portion, so that the performance of urine storage while temporarily storing is further improved, and the absorption rate is further increased. The rewetting property can be further improved.

  According to the present invention, the core wrap sheet is made of thermoplastic synthetic fiber as a main raw material (that is, the content of thermoplastic synthetic fiber is 50% by mass or more), and the core wrap sheet is placed on the lower surface side of the absorbent core. A plurality of flanges projecting from the second surface toward the first surface, and from the first surface toward the second surface, at least part of the region; A plurality of recessed groove portions, and the plurality of flange portions and the plurality of groove portions extend in a direction parallel to the longitudinal direction of the absorbent core and are alternately provided in the second direction. Even when repeatedly exposed to a large amount of body fluid such as urine, the bulkiness is unlikely to be impaired, and the strength is unlikely to be reduced, so that the gap between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid-impermeable back sheet Maintain liquid transport channel between Rukoto can. As a result, high liquid diffusibility can be maintained between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid-impermeable back sheet, and as a result, the absorbent article maintains a high liquid absorption rate. can do. Even if the core wrap sheet is crushed in the thickness direction by receiving a load and the bulk of the sheet is reduced, the core wrap sheet in the present invention is excellent in bulk recoverability. And a liquid transport channel can be restored between the core wrap sheet and the liquid-impermeable backsheet. Further, the core wrap sheet has a region that contacts the lower surface side of the absorbent core, and at least part of the region includes a plurality of flanges and a plurality of grooves extending in parallel with the longitudinal direction of the absorbent core. The diffusion of body fluid in the longitudinal direction of the core can be promoted. As a result, the liquid absorption rate can be increased, and the body fluid that could not be absorbed by the absorption core can be prevented from overflowing and leaking. Furthermore, the core wrap sheet has the above pattern shape, thereby improving the flexibility and stretchability of the core wrap sheet, increasing the ability of the core wrap sheet to deform following the movement of the wearer, and absorbing the core wrap sheet. It is possible to improve the feeling of wearing the property article.

FIG. 1 is a developed view of an absorbent article according to one of the embodiments of the present disclosure. 2 (A) and 2 (B) are cross-sectional views taken along line III-III of the absorbent body used in the absorbent article shown in FIG. 1, and FIG. 2 (A) shows a single absorbent core. Sectional drawing of the absorber covered with the core wrap sheet | seat is shown, FIG.2 (B) shows sectional drawing of the absorber with which the absorption core is covered with the upper core wrap sheet | seat and the lower core wrap sheet | seat. FIG. 3 is a plan view schematically showing one embodiment of a core wrap sheet. 4A is a partial perspective view taken along line IV-IV of the core wrap sheet shown in FIG. 3, and FIG. 4B is a partial cross-sectional perspective view schematically showing another embodiment of the core wrap sheet. FIG. FIG. 5 is a diagram schematically illustrating an example of a manufacturing apparatus for manufacturing a core wrap sheet. FIG. 6 is an enlarged perspective view of a main part schematically showing a pair of shaping rolls of a shaping apparatus that can be used for producing a core wrap sheet. FIG. 7 is an enlarged view of a main part schematically showing the arrangement of pins of the lower shaping roll. FIG. 8 is an enlarged view of a main part showing the meshing state of the upper shaping roll and the lower shaping roll. FIG. 9 is a plan view schematically showing one embodiment of an absorbent core that can be used in the absorbent article of the present invention. FIG. 10 is a plan view schematically showing another embodiment of an absorbent core that can be used in the absorbent article of the present invention. FIG. 11 is a partial perspective view of the absorbent core according to the embodiment shown in FIG.

The absorbent article of the present invention will be described in detail below.
FIG. 1 is a developed view (front view) of an embodiment of the absorbent article of the present invention, and more specifically, a developed view of a disposable diaper 1. The disposable diaper 1 shown in FIG. 1 includes a liquid-permeable sheet 2, a liquid-impermeable sheet (not shown), and an absorbent body 3 between the liquid-permeable sheet 2 and the liquid-impermeable sheet. The disposable diaper 1 shown in FIG. 1 also has a pair of three-dimensional gathers 4 and a pair of tape fasteners 5. In the disposable diaper 1 shown in FIG. 1, the lower side of the paper is the front side of the wearer, and the upper side of the paper is the back side of the wearer. The longitudinal direction (longitudinal direction) D1 and the short direction (lateral direction) D2 of the absorbent body 3 correspond to the longitudinal direction D1 and the short direction D2 of the disposable diaper 1, respectively.

  2 (A) and 2 (B) are cross-sectional views taken along the line III-III of the absorbent body used in the absorbent article shown in FIG. 1, and FIG. 2 (A) shows a single absorbent core 6. 2B is a cross-sectional view of the absorbent body covered with the core wrap sheet 7, and FIG. 2B shows the absorbent body in which the absorbent core 6 is covered with the lower core wrap sheet 7 ′ and the upper core wrap sheet 7 ″. 2A and 2B, the upper side of the paper surface is the liquid-permeable sheet side, and the lower side of the paper surface is the liquid-impermeable sheet side. The wrap sheet 7 ′ and the upper core wrap sheet 7 ″ have a first surface (upper surface) 7a, 7′a, 7 ″ a and a second surface (lower surface) 7b, 7′b, 7 ″ on the opposite side. b. The absorbent core 6 may be bonded to the core wrap sheet (7, 7 ′, 7 ″) by, for example, a plurality of linear or dotted bonding portions (not shown). It can be formed by an agent.

  In the embodiment of the absorbent body shown in FIG. 2 (A), the lower surface of the absorbent core 6 is in contact with the first surface (upper surface) 7a of the core wrap sheet 7, and the core wrap sheet 7 And at least part of the region extends in a first direction parallel to the longitudinal direction of the absorbent core 6 and is predetermined in a second direction orthogonal to the first direction. A plurality of ridges and a plurality of grooves provided alternately at a given interval. In the embodiment of the absorbent body shown in FIG. 2 (B), the lower surface of the absorbent core 6 is in contact with the first surface (upper surface) 7′a of the lower core wrap sheet 7 ′, and the short direction of the absorbent body At D2, both ends of the lower core wrap sheet 7 ′ and both ends of the upper core wrap sheet 7 ″ are joined. As schematically shown in FIGS. 2 (A) and 2 (B), the core Both the wrap sheet 7 and the lower core wrap sheet 7 'are alternately provided on the second surfaces (lower surfaces) 7b and 7'b at predetermined intervals in the second direction orthogonal to the first direction. A plurality of flange portions and a plurality of groove portions, each groove portion existing between the adjacent flange portions and the flange portion, and a plurality of the plurality of groove portions provided on the second surfaces 7b and 7'b of the core wrap sheets 7, 7 '. The groove portion and the flange portion are respectively a plurality of provided on the first surfaces 7a, 7'a of the core wrap sheets 7, 7 '. Parts and are on opposite sides of the position of the groove.

  In the absorbent article of the present invention, a load (ie, compressive load) is applied to the core wrap sheet in the thickness direction of the core wrap sheet by movement of the wearer and / or a direction in which the core wrap sheet is stretched (ie, core wrap). Even if the volume of the space acting as the liquid transport channel of the core wrap sheet is reduced by applying a load (tensile load) to the core wrap sheet in the in-plane direction defined by the first direction and the second direction of the sheet) Because the core wrap sheet has excellent bulk recoverability, the liquid transport channel can be restored between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid impervious backsheet, thereby High liquid diffusibility can be maintained, and as a result, a high liquid absorption rate can be maintained.

  About the flange on the first surface (upper surface) side of the core wrap sheet, the height from the bottom of the groove to the top of the flange (hereinafter referred to as “upper surface side flange height”) is preferably 0.1 to 5 mm, More preferably, it is 0.2-3 mm, More preferably, it is 0.25-2 mm. In addition, the top part of a collar part is located in the approximate center part of the collar part in a 2nd direction. On the upper surface side, the interval between the apexes of the adjacent ridges (hereinafter referred to as “upper surface ridge interval”) is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, more preferably 0.75. 2 mm. In the upper surface side ridge height and the upper surface side ridge interval in these ranges, a space that acts as a liquid transport channel is formed between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid-impermeable back sheet. The body fluid can be drawn into the space and diffused by capillary action. From the viewpoint of improving liquid diffusibility, the plurality of flanges and grooves may extend continuously from one edge of the core wrap sheet to the other edge in a direction parallel to the longitudinal direction of the absorbent core. preferable. The core wrap sheet has a plurality of flanges and a plurality of grooves as described above, thereby improving the flexibility and stretchability of the core wrap sheet, and the ability of the core wrap sheet to deform following the movement of the wearer. Can be improved, and the wearing feeling of the absorbent article can be improved. The height of the upper side ridges and the interval between the upper side ridges are measured using a two-dimensional laser displacement meter. Examples of the two-dimensional laser displacement meter include a high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Corporation.

  For the core wrap sheet, when the upper side ridge height is less than 0.25 mm, it acts as a liquid transport channel between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid impervious back sheet. It is difficult to form a sufficient space. If the height of the upper surface side ridge exceeds 5 mm, the thickness of the absorbent article increases, which is not preferable when a thin absorbent article is required. On the other hand, if the height is too high, capillary action is difficult to occur. If the top side ridge spacing is less than 0.25 mm, there is sufficient space to act as a liquid transport channel between the absorbent core and the core wrap sheet and between the core wrap sheet and the liquid impervious backsheet. Is difficult. Since the number of continuous ridges and grooves per unit length in the second direction (short direction) of the absorbent core decreases as the distance between adjacent ridges increases, the upper surface side ridge interval exceeds 5 mm. Then, the capillary action is less likely to occur.

  FIG. 3, FIG. 4 (A) and FIG. 4 (B) show an embodiment of the core wrap sheet in the present invention. The core wrap sheet 7 (7 ′) includes an upper surface 12 that is a first surface and a lower surface 13 that is a second surface opposite to the upper surface 12 in FIGS. 3, 4A, and 4B. A plurality of flanges 14 projecting from the lower surface 13 toward the upper surface 12, and a plurality of groove portions 15 recessed from the upper surface 12 toward the lower surface 13. The plurality of flanges and the plurality of grooves extend alternately in a first direction parallel to the longitudinal direction D1 of the absorbent core and are alternately provided at predetermined intervals in a second direction (D2) orthogonal to the first direction. ing. Each groove portion 15 is formed between adjacent flange portions and has a bottom portion 16. The bottom 16 of the groove 15 has a plurality of recesses 17 that are recessed from the first surface toward the second surface and are provided discontinuously in the first direction. Each recess 17 has a peripheral wall 18 and a bottom 19. When the core wrap sheet is in the embodiment having the concave portion 17 in the bottom portion 16 of the groove portion 15, hereinafter, the bottom portion 16 of the groove portion 15 is referred to as a first bottom portion, and the bottom portion 19 of the concave portion 17 is referred to as a second bottom portion. In the embodiment shown in FIGS. 4A and 4B, the peripheral wall 18 includes a pair of first peripheral walls 18a and 18a extending in the first direction and a pair of second peripheral walls 18b extending in the second direction. , 18b, the pair of first peripheral wall portions 18a, 18a are provided to face each other, and the pair of second peripheral wall portions 18b, 18b are provided to face each other. Such a core wrap sheet can be manufactured using, for example, an apparatus described in Japanese Patent No. 5829326. In the absorbent article of the present invention, when the core wrap sheet is viewed from the upper surface side, the core wrap sheet is recessed in two stages, so that the bulk recoverability in the thickness direction of the core wrap sheet can be further increased, Even when repeatedly exposed to body fluids such as urine, a high liquid absorption rate can be maintained. Moreover, since the recessed part 17 of a core wrap sheet | seat has an opening opened to the absorption core side, body fluid which permeate | transmitted the absorption core is temporarily stored in the space in a recessed part, diffusing by said groove part and buttocks. Can do. The body fluid stored in the recess can diffuse through the groove 15 and / or can move to the lower surface 13 side by the capillary action, flow on the lower surface side, and diffuse in the in-plane direction of the core wrap sheet. After diffusion, the body fluid that has moved to the lower surface 13 side passes through the core wrap sheet again, moves to the upper surface side, and is absorbed by the absorbent core.

  In the embodiment shown in FIG. 4 (B), each first peripheral wall portion 18a of the recess 17 has a hole portion 20 that passes through the first peripheral wall portion 18a and leads to the lower surface 13 side of the core wrap sheet 7 (7 ′). Is formed. Since bodily fluid can move from the upper surface 12 side to the lower surface 13 side of the core wrap sheet 7 (7 ′) through the hole 20, the body fluid flows from the upper surface 12 side to the lower surface 13 side of the core wrap sheet 7 (7 ′). Can facilitate the transition. In the embodiment shown in FIG. 4B, the hole 20 is formed at a position near the second bottom 19 of the recess 17 in the first peripheral wall 18a, and there are two holes 20 in each recess 17. To do. In the embodiment shown in FIG. 4 (B), the hole is not provided in the second peripheral wall portions 18b and 18b. In the said embodiment, although the hole 20 of the recessed part 17 is provided in a pair of 1st surrounding wall part formed along the 1st direction, the hole was formed so that the 2nd direction might be met. It may be provided in a pair of 2nd surrounding wall parts, and the composition provided in any 1 surrounding wall part may be sufficient.

  In the embodiment shown in FIGS. 4A and 4B, on the upper surface (first surface) side, the distance from the height of the first bottom portion to the height of the upper surface side of the second bottom portion (hereinafter referred to as “upper surface”). The side recess depth is preferably 10 to 80%, more preferably 15 to 70%, and more preferably 20 to 60% of the height of the upper side ridge. If the depth of the upper surface side concave portion is less than 10% of the height of the upper surface side collar portion, a space having a sufficient volume for storing body fluid cannot be secured in the concave portion 17. When the depth of the upper surface side concave portion exceeds 80% of the height of the upper surface side collar portion, the concave portion 17 becomes too deep, which is not preferable when the thickness of the absorbent article increases and a thin absorbent article is required. The length of the concave portion in the first direction is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and more preferably 0.75 to 2 mm. The length of the recess in the second direction is preferably 0.25 to 5 mm, more preferably 0.5 to 3 mm, and even more preferably 0.75 to 2 mm, although it depends on the distance between the upper side flanges. If the length of the concave portion in the first direction and / or the second direction is less than 0.25 mm, the concave portion is too small, so that the effect of temporarily storing the body fluid that has passed through the absorbent core is not sufficiently exhibited. . Although it depends on the upper surface side buttock spacing, if the lengths of the recesses in the first direction and the second direction exceed 5 mm, the capillary action hardly occurs in the space in the recesses, so that the body fluid is diffused in the in-plane direction of the core wrap sheet. Or promoting the transition of the body fluid from the upper surface side to the lower surface side and the transition from the lower surface side to the upper surface side may be difficult. The depth of the upper surface side recess, the length of the recess in the first direction, and the length of the recess in the second direction are measured using a two-dimensional laser displacement meter. Examples of the two-dimensional laser displacement meter include a high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Corporation.

  In the embodiment shown in FIG. 4B, the reason why the hole portion 20 is provided in the second peripheral wall portion 18b of the recess 17 is that when the hole portion 20 is provided in the second peripheral wall portion 18b, the hole portion 20 opens toward the groove on the lower surface (second surface) side adjacent to the recess (that is, the portion on the opposite side of the flange on the upper surface side), and the groove on the lower surface side acts as a liquid transport channel. Therefore, it is possible to promote the transition of the body fluid from the upper surface side to the lower surface side, the transition from the lower surface side to the upper surface side, and as a result, promote the diffusion of the body fluid in the in-plane direction of the core wrap sheet. it can. The holes 20 are preferably formed without melting the thermoplastic resin fibers of the core wrap sheet 7 (7 '). When the thermoplastic resin fiber is melted and cut, the end of the fiber is melted and rounded, so that the fiber diameter is increased. As a result, the capillary action is less likely to occur at the peripheral portion of the hole 20, so that the thermoplastic resin It is preferable to form the hole by breaking the fiber. In the internal space of the hole 20, the fibers spanned in the internal space and a part of the extended fibers are mixed, and the space is not completely open. Is preferred. The opening ratio of the internal space of the hole is preferably 1 to 50%, more preferably 1.5 to 35%, and more preferably 2.5 to 20%. If the opening ratio of the internal space of the hole portion is less than 1%, the effect provided by the hole portion is insufficient, and if the opening ratio is 50% or more, the first peripheral wall portion where the hole portion is provided. The strength tends to be low. However, the open area ratio of the internal space of the hole may be outside the above range depending on the type and application of the absorbent article of the present invention, and can be arbitrarily set.

In the absorbent article of the present disclosure, the core wrap sheet has thermoplastic synthetic fibers as a main component (that is, contains 50% by mass or more). The core wrap sheet may contain other constituent fibers as long as the main component is thermoplastic synthetic fiber (that is, 50% by mass or more). Examples of thermoplastic synthetic fibers include polyethylene, polypropylene, polybutylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, polyolefin such as ionomer resin; polyethylene terephthalate, poly Examples include polyesters such as butylene terephthalate, polytrimethylene terephthalate, and polylactic acid; polyamides such as nylon. Examples of other constituent fibers include, for example, wood or non-wood pulp fibers, natural fibers (such as wool and cotton), regenerated cellulose fibers (such as rayon and acetate), and inorganic fibers (such as glass fibers and carbon). Fiber etc.). The fibers constituting the core wrap sheet are: core / sheath fibers, side-by-side fibers, island / sea fibers, etc .; hollow fibers; flat fibers, Y-shaped fibers, C-shaped fibers, etc .; It is possible to have a form of a three-dimensionally crimped fiber of latent crimp or actual crimp; a split fiber that is split by a physical load such as water flow, heat, embossing, or the like. The core wrap sheet is, for example, for forming a web (fleece) and a nonwoven fabric manufactured by a method of physically and chemically bonding fibers together to form the above-described ridges, grooves, and recesses as necessary. It can be manufactured by shaping. Examples of the web forming method include a dry method (spun bond method, card method, melt blown method, airlaid method, etc.), a wet method, and the like. Examples of the bonding method include a thermal bond method, a chemical bond method, and a needle. Examples thereof include a punch method, a stitch bond method, and a spun lace method. In addition to the nonwoven fabric produced in this manner, a spunlace formed into a sheet shape by a hydroentanglement method may be used. The basis weight of the shaping processing object of the nonwoven fabric is usually a 10~75g / m ^2, preferably from 10 to 45 g / m ^2, more preferably from 10 to 25 g / m ^2. The thickness of the non-woven fabric to be shaped is usually 0.1 to 5 mm, preferably 0.2 to 3 mm, and more preferably 0.4 to 2 mm.

Hereinafter, a method for manufacturing the core wrap sheet 7 (7 ′) having the above-described configuration will be described.
FIG. 5 shows an example of a manufacturing apparatus for manufacturing the core wrap sheet 7 (7 ′), and FIG. 6 shows a pair of shaping rolls of the shaping apparatus provided in the core wrap sheet manufacturing apparatus. It is a principal part expansion perspective view shown typically. FIG. 7 is an enlarged view of the main part schematically showing the arrangement of the pins of the lower shaping roll, and FIG. 8 is an enlarged view of the main part showing the meshing state of the upper shaping roll and the lower shaping roll. It is. The manufacturing apparatus 50 shown in FIG. 5 is unwound by the unwinding apparatus 52 which unwinds the nonwoven fabric 51 processed into the core wrap sheet 7 (7 ') in roll shape, and unwinds the nonwoven fabric 51 toward conveyance direction MD. A preheating device 61 that preheats the non-woven fabric 51, and a shaping device 62 that performs a shaping process for forming the above-described ridges, grooves, and recesses as needed on the preheated non-woven fabric 51.

  As the thermoplastic synthetic fiber used for the nonwoven fabric to be processed, a fiber having high opacity, particularly high whitening property, can be used from the viewpoint of concealment of body fluid when used for an absorbent article. The thermoplastic synthetic fiber may contain, for example, a light transmission inhibitor (such as titanium oxide) that makes the fiber opaque. For thermoplastic synthetic fibers, antioxidants, light stabilizers, UV absorbers, neutralizers, nucleating agents, epoxy stabilizers, lubricants, antibacterial agents, flame retardants, antistatic agents, pigments, if necessary Additives such as a plasticizer may be added. The thermoplastic synthetic fiber is preferably hydrophilized with a surfactant, a hydrophilic agent or the like.

  In this embodiment, the preheating device 61 includes a pair of upper and lower heating rolls 61a and 61b, and the nonwoven fabric 51 that has been conveyed is wound around the rotating lower heating roll 61b and heated, and then rotated. Then, the nonwoven fabric 51 can be heated again by the heating roll 61a. Further, the shaping device 62 includes a pair of upper and lower stretching rolls 63, 64. As shown in FIG. 6, the upper stretching roll 63 is disposed at regular intervals in the roll width direction. A plurality of protruding ridges 63a provided in parallel with each other along the outer peripheral surface of the extending roll 63, and a plurality of concave grooves 63b provided between adjacent protruding ridges 63a, 63a. On the other hand, the lower drawing roll 64 includes a plurality of pins 64 a provided on the outer peripheral surface so as to mesh with the concave grooves 63 b of the upper drawing roll 63. As shown in FIG. 8, these pins 64a are arranged at regular intervals so as not to come into contact with the ridges 63a of the upper extending roll 63 in the roll width direction, and the circumferential direction of the roll. Are arranged substantially linearly at regular intervals along the outer peripheral surface. As shown in FIG. 7, the lower stretching roll 64 in this embodiment has a configuration in which a plurality of pins 64 a are arranged in a staggered manner on the outer peripheral surface of the lower stretching roll 64.

  When implementing the manufacturing method of core wrap sheet 7 (7 ') using the manufacturing apparatus 50 which has the said structure, the preheating process and the preheating process which preheat the nonwoven fabric 51 unwound from the unwinding apparatus 52 are carried out. A shaping step of shaping the passed nonwoven fabric 51 is sequentially performed. In the preheating step, the nonwoven fabric 51 unwound from the unwinding device and transported along the transport direction MD is sequentially brought into contact with the outer peripheral surfaces of the pair of upper and lower heating rolls 61a and 61b rotating in the preheating device 61. Thus, the nonwoven fabric 51 is preheated. The preheating temperature depends on the type of thermoplastic resin fiber constituting the nonwoven fabric. For example, in the case of a core-sheath type composite fiber of polyethylene terephthalate (PET) and high density polyethylene (HDPE), the temperature of the outer peripheral surface of the heating roll is It is preferable that it is about 60-120 degreeC. In the shaping step, the nonwoven fabric 51 that has been conveyed through the preheating step is inserted between a pair of upper and lower stretching rolls 63 and 64 that rotate while meshing in the shaping device 62, and the nonwoven fabric 51 is meshed. The shape is formed by stretching between the protruding ridge 63a and the concave groove 63b of the upper stretching roll 63 and the pin 64a of the lower stretching roll 64. In addition, when implementing a shaping process, it is preferable to shape, heating the extending | stretching rolls 63 and 64 at 60-120 degreeC so that shaping may be performed easily. At this time, the upper drawing roll 63 pushes the part where the ridge 63a is in contact with the nonwoven fabric 51 in the direction of the lower drawing roll 64, whereby the collar portion 14 is shaped. On the other hand, the lower drawing roll 64 has the same concave groove 63b of the upper drawing roll 63 as the non-woven fabric 51 in which the plurality of pins 64a arranged in a line in the circumferential direction are in contact with the tip portion of the pin 64a. Push in. At this time, a portion of the nonwoven fabric 51 that is pulled into the concave groove 63 b in a non-contact state with the pin 64 a becomes the groove portion 15. In addition, since the portion that has been in contact with the tip portion of the pin 63a is strongly pushed into the concave groove 63b and shaped, the first peripheral wall portion 18a extending in the extending direction of the flange portion 14 and the groove portion 15 thereby. And the 2nd surrounding wall part 18a extended in a roll width direction and the recessed part 17 which has the bottom part 19 are formed. In addition, about the bottom part 19 of the recessed part 17, in the state in which the upper extending | stretching roll 9 and the lower extending | stretching roll were biting the nonwoven fabric 51 at the time of formation, the front-end | tip part of the pin 63a made a groove | channel Push into 63b.

  In the nonwoven fabric 51, the portion that has been in contact with both ends in the width direction (roll width direction) of the tip portion of the pin 64 a also has the tension generated when the ridge 63 a pushes the nonwoven fabric 51 in the direction of the lower stretching roll 64. The pin 64a scrapes the thermoplastic resin fibers forming the first peripheral wall portion 8a, or breaks the fibers to form a broken fiber having a broken end. Thereby, the hole 20 including the broken end portion of the broken fiber is formed in the concave portion 17. In addition, some thermoplastic resin fibers remain in a state of being spanned in the internal space of the hole 20, and the broken end portions of some broken fibers are in a state of extending into the internal space. Here, the hole 20 is formed in the direction along the conveyance direction MD of the nonwoven fabric 51, that is, in the rotation direction of the stretching rolls 63 and 64, and in the direction in which the flange 14 and the groove 15 extend. The hole portion 20 is also formed in the first peripheral wall portion 18a along the direction in which the flange portion 14 and the groove portion 15 extend. In the above embodiment, the recess 17 is formed in a substantially rectangular parallelepiped shape, but the shape of the recess can be any shape such as a columnar shape or a prismatic shape. An absorbent article can be manufactured according to a well-known method using the nonwoven fabric which the shaping process was complete | finished as the core wrap sheet 7 (7 ') for absorbent articles.

In the absorbent article of the present disclosure, the absorbent core preferably has one or more main grooves extending in the longitudinal direction on the lower surface side. The main groove portion can extend linearly or non-linearly, for example, curved, in the longitudinal direction. Since one or more main grooves extending in the longitudinal direction on the lower surface side of the absorbent core can secure a space between the absorbent core and the core wrap sheet, the body fluid is temporarily stored and diffused in the longitudinal direction. Therefore, the absorption rate can be increased, and the absorbed liquid can be made difficult to return to the wearer side, that is, the rewetting property can be improved. The main groove portion preferably has a width of 2 to 8 mm, more preferably 3 to 6 mm. When the width of the main groove is within the above range, the main groove easily retains its shape after the absorbent article has absorbed the liquid. In addition, in this specification, the thickness (mm) of the absorber is in a standard state (by a FS-60DS [measurement surface 44 mm (diameter), measurement pressure 3 g / cm ² ) manufactured by Daiei Kagaku Seisakusho Co., Ltd.] The temperature is 23 ± 2 ° C. and the relative humidity is 50 ± 5%), and the pressure is applied to five different parts of the absorber, and the average value of the five measured values obtained by measuring the thickness after 10 seconds at each part is indicated. The depth of the main groove is preferably 2 mm or less, more preferably 2 mm to 0.5 mm. The absorption core is easy to bend with the main groove portion 31 as a base point and is excellent in fit even before absorbing liquid and after repeatedly absorbing liquid. As a result, the absorbent article of the present invention is excellent in wearing feeling both before absorbing the liquid and after absorbing the liquid (particularly after repeatedly absorbing the liquid).

  FIG. 9 is a plan view schematically showing one embodiment of an absorbent core that can be used in the absorbent article of the present invention. In the embodiment shown in FIG. 9, the absorbent core 6 has three main groove portions 31 along the longitudinal direction D1 on the lower surface side. The three main groove portions 31 continuously extend from one end edge of the absorbent core 6 to the other end edge. In the embodiment shown in FIG. 9, the three main groove portions 31 are provided in the central region in the short direction D2 of the absorbent core, but the number and position of the main groove portions 31 are not limited to the embodiment shown in FIG. .

  10 is a plan view schematically showing another embodiment of an absorbent core that can be used in the absorbent article of the present invention, and FIG. 11 is a cross-sectional view taken along line VV of the absorbent core of the embodiment shown in FIG. It is a fragmentary perspective view. In the embodiment shown in FIGS. 10 and 11, the absorbent core 6 has three main groove portions 31 extending in the longitudinal direction D1 and a plurality of secondary groove portions 32 branched from each main groove portion 31 in the short direction D2 of the absorbent core 6. . Since the absorbent core has the follower groove portion 32 in addition to the main groove portion 31, the liquid diffused in the longitudinal direction through the main groove portion diffuses in the short direction through the follower groove portion 32, so that the absorption core 6 has a wide range. Absorbed in. As a result, the rewetting property of the absorbent article can be further enhanced. It is preferable that the sub groove part is connected with the main groove part 31 by the base end, and the absorption core exists in the front-end | tip. Depending on the application of the absorbent article, the number of sub-grooves is preferably 0.05 to 1, more preferably 0.1 to 0.5 per unit length (1 cm) of the main groove. When the number of sub-grooves is provided within the predetermined range, the sub-groove part into which the liquid is divided when the liquid supplied to the absorber reaches the sub-groove and diffuses in a direction other than the longitudinal direction. Through the terminal end, it becomes easier to be effectively absorbed by the inside of the absorbent core due to the capillary phenomenon, so that the rewetting property of the absorber can be further improved.

  The absorbent core in the absorbent article of the present disclosure is, for example, a material that forms the absorbent core in a mold that includes a region corresponding to the main groove portion of the absorbent core or a recess having protrusions in the region corresponding to the main groove portion and the sub groove portion (for example, It can be formed by depositing pulp and SAP. Specifically, it can be formed according to the method described in JP 2010-233839 A, JP 2014-136126 A, etc. of the same applicant. The absorbent core can be an absorbent core known in the art and can include a polymeric absorbent. Examples of the polymer absorbent include polymer absorbents known in the art, for example, starch-based, cellulose-based, and synthetic polymer-based polymer absorbents.

  The absorbent article of the present disclosure is not particularly limited, for example, an absorbent article that mainly absorbs urine, for example, a disposable diaper, a urine collection pad, an animal urination sheet, etc. Examples of the property article include sanitary napkins and panty liners. The absorbent article is preferably an absorbent article that mainly absorbs urine from the viewpoint that the effects of the present disclosure can be further exhibited.

  Hereinafter, although an example is given and this indication is explained, this indication is not limited to these examples.

[Lower core wrap sheet A]
A hydrophilic polypropylene (PP) spunbond (SB) nonwoven fabric (basis weight 15 g / m ² , manufactured by Asahi Kasei Co., Ltd.) 170 mm (length in the direction parallel to the short direction of the absorbent core) × 350 mm (length of the absorbent core) The length of the direction parallel to the direction) was cut to produce a lower core wrap sheet A. Similarly to the lower core wrap sheet A, the following lower core wrap sheets B1, B2, C1, C2, D1, and D2 have a length along the longitudinal direction of the absorbent core before covering the absorbent core of 350 mm. It was.

[Lower core wrap sheet B1]
A lower core wrap sheet B1 was produced by processing a hydrophilic PP spunbonded nonwoven fabric (basis weight 15 g / m ² , manufactured by Asahi Kasei Co., Ltd.) using the manufacturing apparatus shown in FIGS. Specifically, the PP spunbonded nonwoven fabric was preheated with a pair of heating rolls 61 a and 61 b having an outer peripheral surface temperature of 90 to 95 ° C., and then shaped with a pair of stretching rolls 63 and 64. The conveyance speed of the nonwoven fabric was 150 m / min. The shaped nonwoven fabric has a plurality of ridges and grooves on both sides, and a plurality of recesses corresponding to the recesses 19 shown in FIGS. 4A and 4B on the surface in contact with the stretching roll 64. Was. The plurality of flanges and grooves extended continuously from one edge of the core wrap sheet to the other edge. In the shaped nonwoven fabric, the side having the plurality of recesses 19 corresponds to the upper surface side of the sheet in the absorbent article. The shaped nonwoven fabric was cut into a size of 170 mm × 350 mm to produce a lower core wrap sheet B1. When obtained by observation with an electron microscope, the height from the bottom of the continuous groove to the top of the continuous collar is 1.0 mm on the upper surface side of the lower core wrap sheet B1, and between the tops of the adjacent collars The interval was 1.0 mm. The concave portion had a substantially rectangular parallelepiped space, and the depth of the concave portion was about 0.2 mm.

[Lower core wrap sheet B2]
A lower core wrap sheet B2 was produced in the same manner as the lower core wrap sheet B1, except that the size was changed to 120 mm × 350 mm. The lower core wrap sheet B2 has a plurality of flange portions and groove portions that continuously extend from one end edge to the other end edge on both surfaces, and the surface in contact with the stretching roll 64 as shown in FIG. A plurality of recesses corresponding to the recess 19 shown in FIG.

[Lower core wrap sheet C1]
Tissue paper (basis weight 16 g / m ² , manufactured by Nitto Co., Ltd.) was cut into a size of 170 mm × 350 mm to prepare a lower core wrap sheet C1.

[Lower core wrap sheet C2]
Tissue paper (basis weight 16 g / m ² , manufactured by Nitto Co., Ltd.) was cut into a size of 120 mm × 350 mm to prepare a lower core wrap sheet C2.

[Lower core wrap sheet D1]
Lower core wrap sheet with a size of 170 mm × 350 mm, similar to the lower core wrap sheet B1, except that the hydrophilic PP spunbonded nonwoven fabric was replaced with tissue paper (basis weight 16 g / m ² , manufactured by Nitto Co., Ltd.) D1 was produced. The lower core wrap sheet D1 has a plurality of flange portions and groove portions extending continuously from one end edge to the other end edge on both sides, and the surface in contact with the stretching roll 64 in FIG. A plurality of recesses corresponding to the recess 19 shown in FIG.

[Lower core wrap sheet D2]
A lower core wrap sheet D2 was produced in the same manner as the lower core wrap sheet D1, except that the size was changed to 120 mm × 350 mm. The lower core wrap sheet D2 has a plurality of flange portions and groove portions extending continuously from one end edge to the other end edge on both sides, and the surface in contact with the stretching roll 64 is shown in FIG. A plurality of recesses corresponding to the recess 19 shown in FIG.

[Upper core wrap sheet T1]
An upper core wrap sheet T1 was prepared in the same manner as the lower core wrap sheet A except that the size was changed to 120 mm × 350 mm. When the absorbent body is manufactured using the upper sheet T1, the upper sheet T1 is disposed on the upper surface of the absorbent core, and then both side portions of the lower core wrap sheet having a size of 170 mm × 350 mm are shown in FIG. As shown, the side surface was covered from the lower surface side of the absorbent core so as to be joined to the end portion in the short direction of the upper core wrap sheet T1. In the following Tables 1 and 2, the absorbent body produced by such a method is represented as “upper surface side” with respect to “upper and lower core wrap sheet joining positions”.

[Upper core wrap sheet T2]
Similarly to the lower core wrap sheet A, an upper core wrap sheet T1 having a size of 170 mm × 350 mm was produced. When producing an absorbent body using the upper core wrap sheet T2, after placing the lower core wrap sheet having a size of 120 mm × 350 mm on the lower surface of the absorbent core, both sides of the upper sheet T2 are placed on the upper surface side of the absorbent core. The side was covered so that it might be joined to the lateral direction side part of the lower core wrap sheet. In the following Tables 1 and 2, the absorbents produced by such a method are shown in Tables 1 and 2 below, and in the following Tables 1 and 2, the “upper and lower core wrap sheet joining positions” are shown. , And expressed as “lower surface side”.

[Production of absorber]
The absorbent body was produced by preparing the absorbent core as described below and then covering the absorbent core with the upper core wrap sheet and the lower core wrap sheet produced as described above.
While the pulp is pulverized into a cotton form with a hammer mill so as to have the basis weight described in Table 1 and Table 2, it is pneumatically conveyed to a molding recess having a size of 350 mm × 120 mm (longitudinal direction × short direction) of the suction box. The pulp layer of the absorption core was formed while laminating, but the blending ratio of the SAP was adjusted by dividing the pulp supply time into the first half and the second half and changing the SAP supply amount. The first half of the pulp and SAP supply time corresponds to the lower layer, and the second half corresponds to the upper layer. Uniform blending uses the same amount of SAP supply in the first half and the latter half, and the SAP blend ratio of 70:30 for the upper layer and the lower layer supplies 30% of the total supply of SAP in the first half, and then the remaining 70%. Can be created by supplying and laminating in the second half Next, the absorbent core was extracted from the recess for molding to obtain an absorbent core having a size of 350 mm × 120 mm (longitudinal direction × short direction). In the absorbent bodies of Examples 4, 5 and 9, the absorbent core has four main groove portions (groove length: 350 mm, groove width: 4 mm) extending linearly in the longitudinal direction on the lower surface (back sheet side surface). Had. The space | interval of the edge of the adjacent main groove part of a transversal direction was 18 mm. The absorbent core further had 14 slave groove portions (groove length (short direction length): 6 mm, groove width: 4 mm) branched from each main groove portion. The distance between the ends of the adjacent slave grooves in the longitudinal direction was 20 mm, and the distance between the ends of the slave grooves adjacent to each other in the short direction was 6 mm. These main and secondary groove portions had a basis weight of 150 g / m ² . The pulp used was Super Soft N manufactured by IP, and the SAP used was an Aquakeep (registered trademark) water retention 40 times type manufactured by Sumitomo Seika Co., Ltd. A hot melt adhesive is applied in a spiral manner at a coating amount of 6 g / m ² to the upper core wrap sheet and the lower core wrap sheet produced as described above, and the absorbent core is formed with the upper core wrap sheet and the lower core wrap sheet. The obtained laminate was covered with a hydraulic press to obtain a 2.4 mm thick absorber.

[Production of absorbent articles]
A liquid-permeable top sheet (air-through nonwoven fabric manufactured by Unicharm Kokumi Non-Woven Co., Ltd.) is pasted on the upper surface (surface on the upper core wrap sheet side) of the absorbent body manufactured as described above, and the lower surface (lower core wrap) A liquid-impermeable back sheet (polyethylene film manufactured by Fukusuke Kogyo Co., Ltd.) was attached to the sheet-side surface to prepare an absorbent article sample.
The obtained absorbent article samples were evaluated by the following test methods, and the evaluation results are shown in Tables 1 and 2 below together with the structure of the absorber. In Table 1 and Table 2 below, for the lower core wrap sheet, the symbol “SB” represents a hydrophilic PP spunbond nonwoven fabric, and the symbol “T” represents tissue paper.

[Absorbability test]
(1) The absorbent article sample is set in a U-shaped instrument whose side view is substantially U-shaped. In addition, an absorbent article is set to a U-shaped instrument so that the center position of the longitudinal direction of an absorber and the position of a U-shaped instrument center part (position with the lowest height) may be matched.

<First cycle>
(2) 80 mL of artificial urine (first time) is injected into the center of the absorber from the burette at a rate of 80 mL / 10 seconds.
(3) Record the time from the start of the first artificial urine injection until the artificial urine in the U-shaped instrument disappears as the absorption time (80 mL).
(4) Three minutes after the start of the first artificial urine injection, the outline of the region where the artificial urine has diffused on the liquid-permeable topsheet (TS) side and liquid-impermeable backsheet (BS) side of the absorbent article sample Record (80 mL).

<Second cycle>
(5) Ten minutes after the start of the first artificial urine injection, 80 mL of artificial urine (second time) is injected from the burette into the center of the absorber at a rate of 80 mL / 10 seconds.
(6) The time from the start of the second artificial urine injection until the artificial urine in the U-shaped device disappears is recorded as the absorption time (160 mL).
(7) Three minutes after the start of the second artificial urine injection, record the contour (160 mL) of the region where the artificial urine has diffused on the TS side and BS side of the sample.

<Third cycle>
(8) The operations of (5) to (7) are repeated, the absorption time (240 mL) is measured, and the contour (240 mL) of the region where the artificial urine has diffused on the TS side and BS side of the sample is recorded.

<4th cycle>
(9) The operations of (5) to (7) are repeated, the absorption time (320 mL) is measured, and the contour (320 mL) of the region where the artificial urine has diffused on the TS side and BS side of the sample is recorded.
(10) Four minutes after the start of the fourth artificial urine injection, the absorbent article is taken out of the U-hour device, and the absorbent article is spread on the acrylic flat plate so that the liquid-permeable sheet is on the upper surface. Let stand for a minute.
(11) Five minutes after the start of the fourth artificial urine injection, 60 g of 100 mm × 100 mm filter paper is placed on the liquid-permeable sheet of the absorbent article with the artificial urine injection point as the center. Further, a weight of 3.5 kg, 100 mm × 100 mm × 50 mm (height) is placed on the plate. For filter paper, measure the mass before the test in advance.
(12) Eight minutes after the start of the fourth artificial urine injection, the weight is removed, the mass of the filter paper is measured, the mass of the filter paper before the test is subtracted, and the difference is defined as the rewet amount.
(13) The diffusion length of the artificial urine in the longitudinal direction of the absorbent article is measured from the contour (160 mL to 320 mL) of the region where the artificial urine has diffused.

  Artificial urine was prepared by dissolving 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride, and about 1 g of pigment: Blue No. 1 in 10 L of ion-exchanged water.

  From Table 1 and Table 2, Example 1 has a lower core wrap sheet obtained by shaping the same raw fabric (hydrophilic PP spunbonded nonwoven fabric) as Comparative Example 1, and the basis weight of pulp and SAP. Compared with the comparative example 1, the absorption time was short especially in the 4th absorption. Example 2 has a lower core wrap sheet obtained by shaping the same raw fabric (hydrophilic PP spunbonded nonwoven fabric) as Comparative Example 2, and an absorbent core having the same basis weight of pulp and SAP It has a lower core wrap sheet obtained by shaping a raw fabric (hydrophilic PP spunbonded nonwoven fabric), and has a short absorption time especially in the fourth absorption compared to Comparative Example 2. Indicated. In comparison with Comparative Example 4, Example 2 showed a short absorption time particularly in the fourth absorption. Example 3 showed a short absorption time, especially in the fourth absorption, compared with Comparative Examples 2, 7 and 8. In Examples 4 and 5, the SAP content on the lower layer side of the absorbent core is lower than that in Example 1, and a groove is provided on the lower surface side of the absorbent core. Absorbability better than 1 was exhibited, and a shorter absorption time than Comparative Example 9 was exhibited. In the absorbent articles of Examples 1 to 5, the core wrap sheet was not torn after the liquid absorbency test. From the above results, it can be seen that the absorbent article of the present invention can maintain high absorbency even when liquid is repeatedly absorbed.

DESCRIPTION OF SYMBOLS 1 Disposable diaper 2 Liquid permeable sheet 3 Absorber 6 Absorbing core 7 Core wrap sheet 7 'Lower core wrap sheet 7 "Upper core wrap sheet 8a 1st surface 8b 2nd surface 12 Upper surface 13 Lower surface 14 Gutter 15 Groove 16 1 bottom portion 17 recess portion 18 peripheral wall portion 19 second bottom portion 20 hole portion 31 main groove portion 32 sub groove portion

Claims (7)

An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet, the absorbent body having an upper surface and a lower surface. And an absorbent core having a longitudinal direction, a lateral direction and a thickness direction, and a core wrap sheet covering at least the lower surface of the absorbent core,
The core wrap sheet includes 50% by mass or more of thermoplastic synthetic fiber, has a first surface and a second surface opposite to the first surface, and the core wrap sheet further includes the absorbent core. A first direction parallel to the longitudinal direction, a thickness direction, and a second direction orthogonal to both the first direction and the thickness direction;
The first surface of the core wrap sheet has a region in contact with the lower surface of the absorbent core, and a plurality of ridges projecting from the second surface toward the first surface in at least a part of the region. And a plurality of grooves recessed from the first surface toward the second surface, the plurality of flanges and the plurality of grooves extend in the first direction, and extend in the second direction. It is provided alternately at predetermined intervals,
Each groove portion of the first surface of the core wrap sheet has a first bottom portion, and further provided on the first bottom portion discontinuously with respect to the first direction, and from the first surface to the second surface. With a plurality of recesses recessed in the direction,
Absorbent article. 2. The absorbent article according to claim 1, wherein the concave portion has a peripheral wall portion and a second bottom portion, and has a hole portion that communicates with the second surface of the core wrap sheet in at least a part of the peripheral wall portion. The absorbent article according to claim 1 or 2, wherein the absorbent core has one or more main grooves extending in the longitudinal direction on the lower surface side. The absorptive article according to claim 3 in which said absorption core has one or more secondary groove parts which intersect said vertical groove part on the undersurface side. The said absorbent core is an absorbent article as described in any one of Claims 1-4 comprised from the blend of a pulp and a super absorbent polymer. The absorbent article as described in any one of Claims 1-5 whose height from the bottom part of the said groove part in the 1st surface side of the said core wrap sheet | seat to the top part of the said collar part is 0.25-5 mm. The absorbent article as described in any one of Claims 1-6 whose space | interval between the top parts of the adjacent collar part in the 1st surface side of the said core wrap sheet | seat is 0.25-5 mm.

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