JP6994368B2 - Absorbent article - Google Patents

Description

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

Absorbent articles such as disposable diapers and sanitary napkins generally include a front sheet that is placed relatively close to the wearer's skin and a back sheet that is placed relatively far from the wearer's skin. , Consists of an absorber interposed between the two sheets. This absorber is typically composed mainly of hydrophilic fibers (water-absorbent fibers) such as wood pulp and further contains water-absorbent polymer particles. For absorbers used in absorbent articles, improving various properties such as flexibility (cushioning property), compression recovery property, and shape retention property is a major issue.

As a technique for improving the absorber, for example, Patent Document 1 describes an absorber containing a thermoplastic resin fiber and a cellulosic water-absorbent fiber, and the thermoplastic resin fiber is the surface of the absorber on the surface sheet side. And those exposed on both the front surface of the absorber on the back sheet side are described. According to the absorber described in Patent Document 1, the thermoplastic resin fiber functions as a skeleton for holding other components of the absorbent such as a cellulosic water-absorbent fiber, and is therefore soft and resistant to twisting. .. Further, Patent Document 1 describes an absorbent article provided with this absorber having a recessed embossed portion formed by embossing from the surface sheet side, and further, in the embossed portion, a thermoplastic resin. It is stated that it is preferable that the fiber is fused with other fibers. The embossed portion described in Patent Document 1 is known in the present technical field as a leak-proof groove or the like, and has been adopted for an absorbent article for the purpose of improving liquid diffusivity and shape retention in the plane direction. There is.

Further, Patent Document 2 describes an absorber containing heat-sealed fibers, a non-woven fabric piece in which the fibers are bonded in advance to give a three-dimensional structure, and hydrophilic fibers. This non-woven fabric piece having a three-dimensional structure is manufactured by crushing the non-woven fabric into small pieces using a crushing means such as a cutter mill method, and FIGS. 1 and 1 of the same document are produced due to such a manufacturing method. As described in No. 3, it has an indefinite shape and does not substantially have a portion that can be regarded as a flat surface. Patent Document 2 describes a preferred form of the absorber described in the same document in which non-woven fabric pieces are heat-fused together. According to the absorber described in Patent Document 2, since the non-woven fabric piece has a three-dimensional structure, voids are formed inside the absorber, and the resilience when absorbing water is improved, and as a result, the water absorption performance is improved. It is said that.

Further, Patent Document 3 describes a fine web having a relatively dense fine fiber nucleus and a fiber or a fiber bundle extending outward from the nucleus, and the fine web and wood pulp or a water-absorbing polymer. It is described that a non-woven web mixed with particles can be used as an absorber for absorbent articles. This fine web is manufactured by peeling or tearing off a raw material sheet such as a non-woven fabric, and has an irregular shape and can be regarded as a flat surface like the non-woven fabric piece described in Patent Document 2. Substantially does not have.

JP-A-2015-16319 JP-A-2002-301105 Japanese Unexamined Patent Publication No. 1-156560

The absorber described in Patent Document 1 further contains synthetic fibers (thermoplastic resin fibers) in addition to the cellulosic water-absorbent fibers, but a plurality of synthetic fibers contained therein are present independently. It does not form a single mass. Therefore, the absorber described in Patent Document 1 does not have sufficient cushioning property, compression recovery property, etc., and therefore, when applied to an absorbent article, it may be easily twisted and the fit may be insufficient. After absorption of body fluids such as urine and menstrual blood, the occurrence of such inconvenience is remarkable.

On the other hand, in each of the absorbers described in Patent Documents 2 and 3, the synthetic fiber contained is a synthetic fiber aggregate called a non-woven fabric piece or a fine web, but as described above, the non-woven fabric mainly composed of synthetic fiber. Because it is manufactured by crushing it into small pieces, or by peeling or tearing it off, it has an indefinite shape and the shape and size are not uniform. When mixed with, it is difficult to obtain a uniform mixture of the two, and there is a possibility that the desired effect cannot be obtained.

Further, from the viewpoint of improving the shape retention of the absorber, as described in Patent Document 2, when all the synthetic fiber aggregates contained in the absorber are heat-sealed to each other, the absorber becomes flexible. The property is impaired, and the improvement of the fit of the absorbent article becomes insufficient. Absorbents containing synthetic fiber aggregates that can achieve both flexibility, fit, and shape retention at a high level have not yet been provided.

Therefore, an object of the present invention is to provide an absorbent article having excellent cushioning property, compression recovery property and shape retention property of the absorber, good wearing feeling and fit, and excellent liquid absorption property.

The present invention has a vertical direction corresponding to the front-back direction of the wearer and a horizontal direction orthogonal to the vertical direction, and in the vertical direction, a vertical central region including an excretion portion facing portion facing the wearer's excretion portion, and the vertical central region. It is divided into an anterior region located on the ventral side of the wearer from the facing portion of the excretion part and a posterior region located on the back side of the wearer from the facing portion of the excretion part. An absorbent article comprising an absorbent body, including a surface sheet arranged on the opposite side, wherein the absorber comprises a fiber mass comprising a plurality of synthetic fibers and a water-absorbing fiber. The surface sheet and the recessed portion in which the absorber is integrally recessed on the non-skin facing surface side of the absorber are partially formed in the absorbent body, and the recessed portion is formed in the recessed portion in the absorbent body. The density is higher than that of the non-recessed portion, which is a portion where the portion is not formed, and in the absorber of the non-recessed portion, a plurality of the fiber lumps are entangled without fusion. be.

The absorbent article of the present invention is excellent in cushioning property, compression recovery property and shape retention property of the absorber, good wearing feeling and fit, and excellent liquid absorption property. These features of the absorber can be manifested not only before and after absorption of the body fluid.

FIG. 1 is a plan view schematically showing an example of a sanitary napkin according to an embodiment of the absorbent article of the present invention, with the skin facing surface side (surface sheet side) partially broken. FIG. 2 is a cross-sectional view schematically showing the I-I line cross section of FIG. FIG. 3 is a schematic perspective view of a part (a portion located in a non-recessed portion) of the absorbent core included in the absorbent article shown in FIG. FIG. 4 is a diagram schematically showing a deformed state of the absorbent core shown in FIG. 3 during compression. FIG. 5 is a plan view schematically showing the skin facing surface side (surface sheet side) of another example of the sanitary napkin according to the embodiment of the absorbent article of the present invention. 6 (a) and 6 (b) are schematic perspective views of the main body of the fiber mass according to the present invention, respectively. FIG. 7 is an explanatory diagram of a method for producing a fiber mass according to the present invention. FIG. 8 (a) is an electron micrograph (observation magnification 25 times) of an example of the fiber mass according to the present invention, and FIG. 8 (b) is the fiber mass contained in the absorbent core shown in FIG. It is a figure which showed schematically the fiber mass of an electron micrograph.

Hereinafter, the present invention will be described based on the preferred embodiment thereof with reference to the drawings. 1 and 2 show a sanitary napkin 1, which is an embodiment of the absorbent article of the present invention. The napkin 1 has an absorber 4 that absorbs and retains body fluid, a liquid-permeable surface sheet 2 that is arranged on the skin-facing surface side of the absorber 4 and can come into contact with the wearer's skin, and a non-absorbent body 4. It is provided with a liquid-impermeable back sheet 3 arranged on the side facing the skin. As shown in FIG. 1, the napkin 1 has a vertical direction X extending from the ventral side of the wearer to the dorsal side via the crotch portion and a lateral direction Y orthogonal to the vertical direction X corresponding to the front-back direction of the wearer. Further, in the vertical direction X, the vertical central region B including the excretion portion facing portion (excretion point) facing the excretion portion such as the wearer's vaginal opening, and the ventral side (anterior side) of the wearer from the excretion portion facing portion. ), And the posterior region C, which is located on the back side (rear side) of the wearer from the excretory portion facing portion.

In the present specification, the "skin facing surface" is a surface of the absorbent article or its constituent members (for example, the absorbent body 4) that is directed toward the skin side of the wearer when the absorbent article is worn, that is, relatively of the wearer. The side closer to the skin, the "non-skin facing surface" is the side of the absorbent article or its constituents that is opposite to the skin side when the absorbent article is worn, that is, toward the side relatively far from the wearer's skin. It is the surface to be. The term "when worn" as used herein means a state in which a normal proper wearing position, that is, a correct wearing position of the absorbent article is maintained.

As shown in FIG. 1, the napkin 1 has an absorbent main body 5 having a shape long in the vertical direction X and both side portions of the absorbent main body 5 along the vertical direction X in the vertical central region B toward the outside in the horizontal direction Y. It has a pair of extending wing portions 5W and 5W. The absorbent main body 5 is a portion that forms the main body of the napkin 1, includes the front surface sheet 2, the back surface sheet 3, and the absorbent body 4, and has the front region A, the vertical center region B, and the rear region C in the vertical direction X. It is divided into three categories.

The vertical central region of the absorbent article of the present invention is a wing in the vertical direction (longitudinal direction, X direction in the figure) of the absorbent article when the absorbent article has a wing portion as in the napkin 1. It means a region having a portion, and taking the napkin 1 as an example, it is a region sandwiched between a root along the vertical direction X of one wing portion 5W and a root along the vertical direction X of the other wing portion 5W. Further, the vertical central region of the absorbent article having no wing portion means a region located in the middle when the absorbent article is divided into three equal parts in the vertical direction.

In the napkin 1, the absorber 4 includes a liquid-absorbable absorbent core 40 and a liquid-permeable core wrap sheet 41 that covers the outer surface of the absorbent core 40. Like the absorbent body 5, the absorbent core 40 has a long shape in the vertical direction X in a plan view as shown in FIG. 1, and the longitudinal direction of the absorbent core 40 is one with respect to the vertical direction X of the napkin 1. However, the width direction of the absorbent core 40 coincides with the lateral direction Y of the napkin 1. The absorbent core 40 and the core wrap sheet 41 may be bonded by an adhesive such as a hot melt type adhesive.

In the napkin 1, the core wrap sheet 41 is one continuous sheet having a width of 2 times or more and 3 times or less the length of the lateral Y of the absorbent core 40, and as shown in FIG. 2, it absorbs. It covers the entire skin-facing surface of the sex core 40 and extends outward in the lateral direction Y from both side edges along the vertical direction X of the absorbent core 40, and the extending portion thereof is below the absorbent core 40. It is rolled down to cover the entire non-skin facing surface of the absorbent core 40. In the present invention, the core wrap sheet does not have to be such a single sheet, for example, one skin-side core wrap sheet that covers the skin-facing surface of the absorbent core 40 and the skin-side. It may be a separate body from the core wrap sheet, and may include two sheets including one non-skin side core wrap sheet that covers the non-skin facing surface of the absorbent core 40.

As shown in FIG. 2, the surface sheet 2 covers the entire surface of the absorber 4 facing the skin. On the other hand, the back surface sheet 3 covers the entire non-skin facing surface of the absorber 4, and further extends outward in the lateral direction Y from both side edges along the vertical direction X of the absorber 4, together with the side sheet 6 described later. A side flap portion (a portion made of a member extending outward in the lateral direction Y from the absorber 4) is formed. The back surface sheet 3 and the side sheet 6 are bonded to each other by known bonding means such as an adhesive, a heat seal, and an ultrasonic seal at the extending portions from both side edges of the absorber 4 along the vertical direction X. Each of the front surface sheet 2 and the back surface sheet 3 and the absorber 4 may be bonded by an adhesive. As the front surface sheet 2 and the back surface sheet 3, various types conventionally used for absorbent articles such as sanitary napkins can be used without particular limitation. For example, as the surface sheet 2, a non-woven fabric having a single-layer or multi-layer structure, a perforated film, or the like can be used. As the back sheet 3, a moisture-permeable resin film or the like can be used.

As shown in FIG. 1, the side flap portions greatly project outward in the horizontal direction Y in the vertical central region B, whereby a pair of side flap portions are formed on the left and right sides of the absorbent main body 5 along the vertical direction X. Wings 5W and 5W are extended. The wing portion 5W has a substantially trapezoidal shape in which the lower base (the side longer than the upper base) is located on the side portion side of the absorbent main body 5 in a plan view as shown in FIG. 1, and the non-skin facing surface thereof. Is formed with a wing portion adhesive portion (not shown) for fixing the wing portion 5W to clothing such as shorts. The wing portion 5W is used by being folded back toward the non-skin facing surface (outer surface) side of the crotch portion of clothing such as shorts. Before its use, the adhesive portion of the wing portion is covered with a release sheet (not shown) made of a film, a non-woven fabric, paper or the like. Further, a pair of both side portions of the absorbent body 5 on the skin-facing surface, that is, the skin-facing surface of the surface sheet 2 along the vertical direction X, overlap with the left and right side portions of the absorbent body 4 along the vertical direction X in a plan view. Side sheets 6 and 6 are arranged over substantially the entire length of the absorbent body 5 in the vertical direction X. The pair of side sheets 6 and 6 are joined to another member such as the surface sheet 2 by a known joining means such as an adhesive by a joining line (not shown) extending in the vertical direction X, respectively.

As shown in FIGS. 1 and 2, the absorbent body 5 is partially formed with a recessed portion 7 in which the surface sheet 2 and the absorber 4 are integrally recessed on the non-skin facing surface side of the absorber 4. Has been done. The absorbent main body 5 has a recessed portion 7 and a non-recessed portion 8 which is a portion in which the recessed portion 7 is not formed.

The recessed portion 7 is formed by applying a pressing process to the napkin 1 (absorbent main body 5) from the skin facing surface, that is, the surface sheet 2 side, and can also be referred to as a “squeezed portion” from the forming method. Due to the method of forming the recessed portion 7, the front surface sheet 2, the core wrap sheet 41 and the absorbent core 40 are integrated toward the non-skin facing surface side (back surface sheet 3 side) of the absorbent core 40. Is depressed. Further, the recessed portion 7 has a higher density than the non-recessed portion 8 due to such a forming method. That is, the absorbent main body 5 has a high-density portion corresponding to the recessed portion 7 and a low-density portion corresponding to the non-recessed portion 8.

Further, the squeezing process applied to the napkin 1 (absorbent body 5) to form the recessed portion 7 is usually to melt the thermoplastic fibers preferably used as the constituent fibers of the fiber mass 11 contained in the absorber 4. Specific examples thereof include known embossing such as heat-embossing and ultrasonic embossing. Due to the method of forming the recessed portion 7, the surface sheet 2, the core wrap sheet 41 and the absorption are formed in the bottom portion of the recessed portion 7, that is, the portion overlapping the recessed portion 7 which is a space portion in a plan view as shown in FIG. The sex core 40 can be heat fused and integrated.

In the napkin 1, as shown in FIG. 1, the recessed portion 7 has a linear shape in a plan view as shown in FIG. 1, and has a pair of left and right vertical recessed portions 7X, 7X extending in the vertical direction X and a horizontal concave portion 7X, 7X. Includes a pair of front and rear lateral recesses 7Y and 7Y that extend. The plurality of vertical recesses 7X and horizontal recesses 7Y are connected to each other at the end portions in the length direction thereof, and the recessed portions 7 as a whole form one closed ring. Each of the pair of vertical recessed portions 7X and 7X has a continuous linear shape extending over the entire length of the vertical central region B in the vertical direction X, respectively. Further, one of the pair of laterally recessed portions 7Y and 7Y exists in the front region A and the other exists in the rear region C, and both of the laterally recessed portions 7Y are outward in the vertical direction X in a plan view. It has a U-shaped or arc-shaped continuous line that is convex toward the napkin 1, and its U-shaped or arc-shaped top is located at the center of the lateral Y of the napkin 1. The central portion of the vertical central region B, that is, the portion including the excretion portion facing portion (excretion point) is located in the ring of the recessed portion 7 forming a closed annular shape in a plan view.

On the other hand, the non-recessed portion 8 is a portion of the absorbent main body 5 in which the recessed portion 7 is not formed, and as shown in FIG. It exists outside the ring. That is, in the napkin 1, at least the peripheral portion of the absorbent main body 5 and the central portion of the vertical central region B (the portion facing the excretion portion and its vicinity) are the non-recessed portions 8.

One of the main characteristic portions of the napkin 1 is the absorbent body 4, particularly the absorbent core 40 which is the main body of the absorbent body 4. FIG. 3 shows a part of the absorbent core 40 (a portion located in the non-recessed portion 8). As shown in FIGS. 2 and 3, the absorber 4, more specifically, the absorbent core 40 includes a fiber mass 11 including a plurality of fibers (synthetic fibers) 11F and a water-absorbing fiber 12F. The fiber lump 11 is a fiber aggregate in which the fibers 11F are intentionally integrated into a lump, whereas the water-absorbent fiber 12F is in a state where the fibers 12F can exist independently without being intentionally integrated. It is present in the absorbent core 40. The fiber mass 11 mainly contributes to the improvement of the flexibility, cushioning property, compression recovery property, shape retention property and the like of the absorbent core 40. On the other hand, the water-absorbent fiber 12F mainly contributes to the improvement of the liquid absorbency and the shape-retaining property of the absorbent core 40. The absorbent core 40 can be said to be substantially the absorber 4 itself, and the following description of the absorbent core 40 is appropriately applied as a description of the absorbent body 4 unless otherwise specified. That is, the present invention includes a case where the absorber is formed only of the absorbent core without containing the core wrap sheet, and in that case, the absorber and the absorbent core have the same meaning.

As used herein, the term "fiber mass" is a fiber aggregate in which a plurality of fibers are grouped together and integrated. Examples of the form of the fiber mass include a sheet piece divided from a synthetic fiber sheet having a certain size. In particular, a non-woven fabric is selected as the synthetic fiber sheet, and a non-woven fabric piece cut out from the non-woven fabric into a predetermined size and shape is preferable as the fiber mass.

At least in the absorbent core 40 of the non-recessed portion 8, that is, the absorbent core 40 in its original form which has not been squeezed, the plurality of fiber lumps 11 and the fiber lumps 11 and the water-absorbent fibers 12F are each of each other. Intertwined. That is, in the absorbent core 40 of the non-recessed portion 8, a plurality of fiber lumps 11 are combined by entanglement between the constituent fibers 11F to form one fiber lump continuum, and the fiber lump continuum is also formed. The water-absorbent fiber 12F is entwined and bonded to. Further, usually, a plurality of water-absorbent fibers 12F are also entangled with each other. At least a part of the plurality of fiber lumps 11 contained in the absorbent core 40 of the non-recessed portion 8 is entangled with another fiber lump 11 or the water-absorbent fiber 12F. In the absorbent core 40 of the non-recessed portion 8, all of the plurality of fiber lumps 11 contained therein may be entangled with each other to form one fiber lump continuum, and the plurality of fiber lumps may be formed. It is possible that the continuums are mixed in a non-bonded state with each other.

Since the fiber lump 11 is excellent in flexibility and the like, by including it in the absorber, the absorber is potentially excellent in flexibility and the like. In the present embodiment, the absorbent core 40 contains a plurality of fiber lumps 11 together with the water-absorbent fibers 12F, and at least in the non-recessed portion 8, the plurality of fiber lumps 11 are entangled with each other without being fused, and further, the fiber lumps 11 Since the water-absorbent fiber 12F and the water-absorbent fiber 12F are also entangled with each other, the absorbent core 40 is excellent in shape retention, flexibility, cushioning property, compression recovery property, etc., for example, when incorporated into an absorbent article. , The absorbent article can be flexibly deformed by an external force (for example, the body pressure of the wearer of the absorbent article) received from various directions, and the absorbent article can be brought into close contact with the wearer's body with good fit.

FIG. 4 schematically shows a deformed state when the absorbent core 40 of the non-recessed portion 8 is compressed by receiving an external force F. In the absorbent core 40 in which the fiber mass 11 which is a fiber aggregate and the water-absorbent fiber 12F which is a non-fiber aggregate coexist, the boundary between the two members 11 and 12F due to the difference in rigidity between the two members 11 and 12F. BL (dotted line in FIG. 4) is particularly easy to bend, and where the boundary BL functions as a bending portion when the absorbent core 40 is deformed, the boundary BL as the bending portion is usually the absorbent core of the non-recessed portion 8. Since it exists over the entire area of 40, the absorbent core 40 flexibly deforms in a responsive manner to various external forces, and when the external force is released, the fiber mass 11 is provided with compression recovery. It can be quickly restored to its original state depending on the sex. Such deformation-recovery properties of the absorbent core 40 can be similarly manifested not only when the absorbent core 40 is compressed, but also when it is twisted. That is, since the absorbent core 40 incorporated in the napkin 1 is arranged in a state of being sandwiched between both thighs of the wearer when the napkin 1 is worn, the absorbent body 4 is the walking motion of the wearer. Depending on the movement of both thighs at this time, it may be twisted around a virtual axis of rotation extending in the vertical direction X, but even in such a case, at least the absorbent core 40 of the non-recessed portion 8 is highly deformed- Since it has recovery characteristics, it easily deforms and recovers against external forces that promote twisting from both thighs, and therefore is less likely to twist, and can impart a high fit to the wearer's body to the napkin 1.

At least in the absorbent core 40 of the non-recessed portion 8, the fibers 11 are bonded to each other by "entanglement of fibers without fusion". The "entanglement" of the fiber lumps 11 and the like includes the following forms A and B.
Form A: A form in which the fiber lumps 11 and the like are not fused but are bonded by the entanglement of the constituent fibers 11F of the fiber lumps 11.
Form B: In the natural state of the absorbent core 40 (a state in which no external force is applied), the fiber lumps 11 and the like are not bonded to each other, but in a state where the absorbent core 40 is subjected to an external force, the fiber lumps 11 and the like are not bonded to each other. A form that can be bonded by entanglement of constituent fibers 11F. The "state in which an external force is applied to the absorbent core 40" as used herein is, for example, a state in which a deformable force is applied to the absorbent core 40 while the absorbent article to which the absorbent core 40 is applied is being worn. ..

In the non-recessed portion 8 of the absorbent core 40 in the present embodiment, as in the form A, the fiber mass 11 is bound to another fiber mass 11 or the water-absorbent fiber 12F by entanglement, that is, "entanglement" between the fibers. In addition, as in Form B, it also exists in a state where it can be entangled with another fiber mass 11 or water-absorbent fiber 12F. The binding of the fibers by entanglement is one of the important points for more effectively expressing the action and effect of the above-mentioned absorbent core 40. In particular, it is preferable that the non-recessed portion 8 has the "entanglement" of the form A from the viewpoint of shape retention. Since the entanglement of the fiber lumps 11 has no adhesive component or fusion and is performed only by the entanglement of the fibers, compared to the connection by "fusion of fibers" as described in Patent Document 2, for example. The entangled individual elements (fiber mass 11, water-absorbent fiber 12F) have a high degree of freedom of movement, so that the individual elements can move to the extent that they can maintain their integrity as an aggregate. .. As described above, the absorbent core 40 is deformed when it receives an external force because the plurality of fiber lumps 11 contained therein or the fiber lumps 11 and the water-absorbent fiber 12F are relatively loosely bonded to each other. It has a possible and gentle shape retention property, and has both shape retention property, cushioning property, compression recovery property, and the like at a high level. The napkin 1 provided with such a high-quality absorbent core 40 has an excellent wearing feeling and can be in close contact with the wearer's body with good fit.

Further, even when a very strong external force repeatedly acts on the absorbent core 40 while wearing the napkin 1, the absorbent body 5 is further squeezed and high in addition to the non-recessed portion 8. Since it has a densified recess 7, the absorbent core 40 is excellent in shape retention and shape stability. For example, the absorbent core 40 constituting the absorbent body 5 having the recessed portion 7 also with respect to an external force such as a strong lateral compressive force applied by both thighs of the wearer of the napkin 1. It does not easily lose its shape, deforms with good responsiveness to external force, and can be quickly restored if the external force is released. Further, in the absorbent main body 5, the recessed portion 7 which is a relatively high density portion and the non-recessed portion 8 which is a low density portion having a relatively low density coexist in the plane direction. , There is a density difference in the plane direction, and the density difference tends to diffuse the body fluid in the plane direction. That is, the napkin 1 can rapidly diffuse the body fluid excreted by the wearer in the plane direction, and therefore, the absorption performance inherent in the absorbent core 40 can be effectively utilized, and therefore the liquid absorbability. It is excellent in and can exhibit high liquid leakage resistance.
From the viewpoint of ensuring that these actions and effects are exhibited more reliably, a thermoplastic fiber is used as the constituent fiber (synthetic fiber) 11F of the fiber mass 11 contained in the absorbent core 40, and in the recessed portion 7, the recessed portion 7 is used. It is preferable that the surface sheet 2, the core wrap sheet 41 and the absorbent core 40 are heat-sealed and integrated with the melting of the thermoplastic fiber in the pressing process at the time of formation.

In particular, in the napkin 1, as shown in FIG. 1, since the recessed portion 7 exists in the front region A and the rear region C, the shape retention and the liquid diffusivity in the plane direction of these regions A and C are enhanced. Has been done. Further, since the non-recessed portion 8 having excellent cushioning property is present in the vertical central region B where the excretory portion facing portion is present, the vertical central region B absorbs body fluid as well as a dry state before absorption of body fluid. Even in the later wet state, it is flexible and rich in cushioning due to the action of the non-recessed portion 8.

Further, in the non-recessed portion 8, there are many space portions formed between the plurality of fiber lumps 11 due to the existence of the plurality of fiber lumps 11 in a state in which the original outer shape thereof is substantially maintained. It exists, and many of them contribute to the development of the excellent cushioning property of the non-recessed portion 8, and can also function as a temporary stock portion of body fluid. Since the napkin 1 has a non-recessed portion 8 that can function as a temporary stock portion of such body fluid in the vertical central region B where the excreted body fluid tends to concentrate, it has an excellent liquid absorption capacity. It is possible to develop a high liquid leakage proof property, and due to its high liquid drawing property, it is possible to reduce the liquid residue on the skin facing surface of the surface sheet 2 and suppress an unpleasant wet feeling and a sticky feeling. When the absorbent core 40 contains a water-absorbing polymer known in the present technology, the body fluid that has reached the absorbent core 40 is first collected in the space (a gap between a plurality of fiber lumps 11). After being temporarily stocked, it will be absorbed and retained by this water-absorbent polymer.

Further, particularly in the napkin 1, as shown in FIG. 1, a non-recessed portion 8 exists in the central portion in the lateral direction Y of the vertical central region B including the excretion portion facing portion, and the non-recessed portion 8 (the excretion portion). Since the recessed portions 7 (vertical recessed portions 7X) are present on both sides of the laterally opposed portion), the excretion portion facing portion and its vicinity, which play a central role as a body fluid absorption site, are present. Flexibility, cushioning property, compression recovery property, shape retention property and the like are sufficiently enhanced, and the above-mentioned action and effect can be more reliably achieved.

From the viewpoint of more reliably achieving the action and effect caused by the presence of the recessed portion 7 and the non-recessed portion 8, it is preferable to set the dimensions and the like of each portion of the napkin 1 as follows.
In the vertical central region B, the separation distance L1 (see FIG. 1) between the side edge of the absorber 4 (absorbent core 40) along the vertical direction X and the concave portion 7 (vertical concave portion 7X) in the horizontal direction Y is preferable. Is 5 mm or more, more preferably 10 mm or more, and preferably 25 mm or less, still more preferably 20 mm or less.
The length, that is, the width L2 (see FIG. 1) of the non-recessed portion 8 in the vertical central region B in the lateral direction is preferably 20 mm or more, more preferably 25 mm or more, and preferably 70 mm or less, further preferably 65 mm or less. be.

The ratio of the total area of the recessed portion 7 to the total area of the skin facing surface of the absorber 4 (absorbent core 40) (recessed portion occupancy rate) is preferably 0.02% or more, more preferably 0.1%. The above, and preferably 15% or less, more preferably 10% or less.
The depth of the recessed portion 7 (7X, 7Y) (the depth from the non-recessed skin facing surface in the surface sheet 2) is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 2 It is 0.0 mm or less, more preferably 1.0 mm or less.

In the napkin 1, the depth of the recessed portion 7 (7X, 7Y) is constant over the total length in the length direction thereof, but may be partially different. Further, the shape and arrangement of the linear recessed portion 7 (7X, 7Y) is not limited to the illustrated form, and can be set in the same manner as that called a leak-proof groove in this type of absorbent article, and is a flat surface. The visual shape is composed of straight lines and / or curved lines, and each line may be a continuous line or a broken line (a form in which two types of portions having different depths are alternately arranged in the extending direction of the linear recessed portion). But it may be.

Further, in the absorbent article of the present invention, the pattern (planar view shape and arrangement) of the concave portion is not limited to the concave portion 7 (7X, 7Y) shown in FIG. It may be a dot shape such as a circle, an ellipse, a rectangle, a triangle, a star, or a heart. The napkin 1A shown in FIG. 5 is an example of adoption of this dot-shaped recessed portion. Hereinafter, the napkin 1A will mainly be described with components different from those of the above-mentioned napkin 1, and the same components will be designated by the same reference numerals and description thereof will be omitted. The description of the napkin 1 is appropriately applied to the components not particularly described.

In the napkin 1A, the plurality of recessed portions 7 each have a circular shape in a plan view, and are arranged in a staggered manner on the skin-facing surface of the absorbent main body 5, that is, the skin-facing surface of the surface sheet 2. Here, the staggered shape means that rows of a plurality of recessed portions 7 arranged at equal intervals in one direction are arranged in a plurality of rows in a direction orthogonal to the one direction and adjacent to each other in a direction orthogonal to the one direction. It refers to an arrangement in which a plurality of recessed portions 7 are displaced from each other in two matching rows. More specifically, when a plurality of rows in which a plurality of recesses 7 are arranged at equal intervals in one direction are projected in a direction orthogonal to the one direction, each recess 7 in a specific row is projected. When a projection image of a recess 7 in another row adjacent to the particular row is placed between (preferably in the middle) the projections of, the plurality of recesses 7 are staggered. I can say. The "staggered arrangement" in the present invention includes not only a form in which a plurality of recessed portions 7 are perfectly arranged as described above, but also a slight unintended arrangement such as an unavoidable deviation in manufacturing. The form in which the deviation occurs is also included.

Further, in the napkin 1A, similarly to the napkin 1, a non-recessed portion 8 exists in the central portion in the lateral direction Y of the vertical central region B including the excretion portion facing portion, and the non-recessed portion 8 (the excretion portion facing portion). There are recessed portions 7 on both sides in the lateral direction Y with the portion) interposed therebetween. Therefore, the napkin 1A also has the same effect as the napkin 1. Further, the shapes and dimensions of the plurality of point-shaped recesses 7 in a plan view may not be uniform or may be different from each other as shown in FIGS. 1 and 5.

Hereinafter, the absorber 4 will be further described. Unless otherwise specified, the following description of the absorber 4 is the original appearance of the absorber 4 of the non-recessed portion 8, that is, a state in which the absorbent body 4 is not squeezed and can exhibit the original function. It is about the absorber 4 of. Further, the following description of the absorber 4 is appropriately applied to the absorbent core 40 unless otherwise specified (the word "absorbent 4" can be appropriately replaced with "absorbent core 40").

One of the main features of the absorber 4 is the outer shape of the fiber mass 11. FIG. 6 shows two typical outer shapes of the fiber mass 11. The fiber mass 11A shown in FIG. 6A has a rectangular parallelepiped shape more specifically than the prismatic shape, and the fiber mass 11B shown in FIG. 6B has a disk shape. The fiber lumps 11A and 11B are common in that they include two opposing base planes 111 and a skeleton plane 112 connecting the two base planes 111. Both the basic surface 111 and the skeleton surface 112 are at a level applied when evaluating the degree of surface unevenness in an article mainly composed of this type of fiber, and are portions where it is recognized that there is substantially no unevenness.

The rectangular parallelepiped-shaped fiber mass 11A of FIG. 6A has six flat surfaces, and of the six surfaces, two facing surfaces having the maximum area are the basic surfaces 111, respectively, and the rest. Each of the four surfaces is a skeletal surface 112. The basic surface 111 and the skeleton surface 112 intersect each other, and more specifically, are orthogonal to each other.
The disk-shaped fiber mass 11B of FIG. 6B has two flat surfaces facing each other in a circular shape in a plan view and a curved peripheral surface connecting the two flat surfaces, where the two flat surfaces are formed. Each surface is a basic surface 111, and the peripheral surface is a skeleton surface 112.
The fiber lumps 11A and 11B are also common in that the skeleton surface 112 has a quadrangular shape, more specifically, a rectangular shape in a plan view.

Examples of the form of the fiber mass include a sheet piece divided from a synthetic fiber sheet having a certain size. That is, the sheet-like fiber mass, which is a preferred embodiment of the fiber mass according to the present invention, is not configured to accumulate a plurality of fibers to form the sheet piece, and has a larger size than the sheet piece. It is manufactured by cutting a large fiber sheet of the above (see FIG. 7), and has a plurality of sheet piece-like fiber lumps having higher morphology as compared with those manufactured by conventional techniques such as Patent Documents 2 and 3. Is.

The fiber mass 11 which is a "standard fiber aggregate" defined by the two basic surfaces 111 and the skeleton surface 112 intersecting the two basic surfaces 111 has a different manufacturing method from the prior art. It can be realized by doing so. As described above, as shown in FIG. 7, a preferable method for producing the fiber mass 11 is to use a raw material fiber sheet 10bs (a sheet having the same composition as the fiber mass 11 and a size larger than the fiber mass 11) as a raw material, a cutter or the like. It is cut into a fixed shape by using the cutting means of. The plurality of fiber lumps 11 thus produced have a more fixed shape and dimensions as compared with those produced by conventional techniques such as Patent Documents 2 and 3. FIG. 7 is a diagram illustrating a method for manufacturing the rectangular parallelepiped-shaped fiber mass 11A of FIG. 6A, and the dotted line in FIG. 7 shows a cutting line. The absorber 4 is blended with a plurality of fiber lumps 11 having uniform shapes and dimensions obtained by cutting the fiber sheet into a fixed shape in this way.

The above description of the fiber mass 11A basically applies to the disk-shaped fiber mass 11B of FIG. 6B. The only substantial difference from the fiber mass 11A is the cutting pattern of the raw material fiber sheet 10bs, and when the sheet 10bs is cut into a fixed shape to obtain the fiber mass 11B, the shape of the fiber mass 11B is matched to the plan view shape. The sheet 10bs may be cut into a circular shape.

As described above, Patent Documents 2 and 3 describe that the plurality of fiber lumps 11 contained in the absorber 4 are "standard fiber aggregates" defined by the basic surface 111 and the skeleton surface 112. Since the uniform dispersibility of the fiber mass 11 in the absorber 4 is improved as compared with the case of an amorphous fiber aggregate such as the above, it is expected that the fiber aggregate such as the fiber mass 11 is blended with the absorber 4. The effect (improvement effect such as flexibility, cushioning property, compression recovery property, etc. of the absorber) will be more stably exhibited. Further, in particular, in the case of the rectangular parallelepiped main body 110 as shown in FIG. 6A, since the outer surface thereof is composed of six surfaces of two basic surfaces 111 and four skeleton surfaces 112, the other fiber mass 11 or water absorption. It is possible to have a relatively large number of contact opportunities with the fiber 12F, the entanglement is enhanced, and the shape retention and the like can be improved.

As the fiber sheet 10bs used here, a non-woven fabric containing synthetic fibers is preferable from the viewpoint of further enhancing the cushioning property, compression recovery property and shape retention property of the absorbent core 40, and a non-woven fabric having a heat-sealed portion between synthetic fibers is preferable. More preferred. Further, an air-through nonwoven fabric in which synthetic fibers have heat-sealed portions and a plurality of heat-sealed portions are three-dimensionally dispersed is particularly preferable.

The outer shape of the main body 110 is not limited to that shown in FIG. 6, and the basic surface 111 and the skeleton surface 112 are both flat surfaces that are not curved as in the surfaces 111 and 112 of FIG. 6A. It may be a curved surface as in the skeleton surface 112 of FIG. 6 (b). Further, the basic surface 111 and the skeleton surface 112 may have the same shape and dimensions, and specifically, for example, the outer shape of the main body 110 may be a cube.

As described above, the two types of surfaces (basic surface 111 and skeleton surface 112) of the fiber mass 11 (11A, 11B) are formed by cutting the raw material fiber sheet 10bs by a cutting means such as a cutter when manufacturing the fiber mass 11. It is classified into a cut surface (skeleton surface 112) to be formed and a non-cut surface (basic surface 111) that is inherently possessed by the sheet 10bs and does not come into contact with the cutting means. Due to the difference in whether or not the cut surface is used, the cut surface, the skeleton surface 112, is characterized in that the number of fiber ends per unit area is larger than that of the non-cut surface, the basic surface 111. Has. The term "fiber end" as used herein means the end in the length direction of the constituent fibers 11F of the fiber mass 11. Normally, the fiber end is also present on the basic surface 111, which is a non-cut surface, but the skeleton surface 112 is formed by cutting because it is a cut surface formed by cutting the raw material fiber sheet 10bs. A large number of fiber ends consisting of cut ends of the constituent fibers 11F are present in the entire skeleton surface 112, that is, the number of fiber ends per unit area is larger than that of the basic surface 111. ..

At the fiber ends existing on each surface (basic surface 111, skeleton surface 112) of the fiber mass 11, the fiber mass 11 is entangled with other fiber mass 11 and the water-absorbent fiber 12F contained in the absorber 4. Is useful for forming. Further, in general, the larger the number of fiber ends per unit area, the better the entanglement, which may lead to the improvement of various properties such as the shape retention of the absorber 4. The number of fiber ends per unit area on each surface of the fiber mass 11 is not uniform, and the magnitude relationship of "skeleton surface 112> basic surface 111" is established for the number of fiber ends per unit area. Therefore, the entanglement with other fibers (other fiber mass 11, water-absorbent fiber 12F) via the fiber mass 11 differs depending on the surface of the fiber mass 11, and the skeleton surface 112 is compared with the basic surface 111. Highly entangled. That is, the bond by entanglement with other fibers via the skeleton surface 112 has a stronger bonding force than that through the basic surface 111, and in one fiber mass 11, the basic surface 111 and the skeleton surface There may be a difference in the bonding force with other fibers from 112. In general, the stronger the binding force, the more the degree of freedom of movement of the bonded fibers is limited, and the strength (shape retention) of the absorber 4 as a whole is improved, but the softness tends to be lowered.

As described above, in the absorber 4, each of the plurality of fiber lumps 11 contained therein has two types of binding forces with respect to other fibers (other fiber lumps 11, water-absorbent fibers 12F) around the absorber 4. The absorber 4 is held and entangled, so that the absorber 4 has appropriate softness and strength (shape retention). When the absorber 4 having such excellent properties is used as an absorber of the absorbent article according to a conventional method, it is possible to provide a comfortable wearing feeling to the wearer of the absorbent article. , The inconvenience that the absorber 4 is destroyed by an external force such as the wearer's body pressure at the time of wearing is effectively prevented.

On the other hand, the non-woven fabric pieces or fine webs described in Patent Documents 2 and 3 have, as described above, as described above.
Since the raw material fiber sheet is manufactured by cutting it into an irregular shape with a cutting machine such as a mill cutter, it is a fixed-sized sheet-like fiber mass having a "face" such as a basic surface 111 or a skeleton surface 112. Moreover, since the external force of the cutting process is applied to the entire fiber mass at the time of its manufacture, the fiber end portions of the constituent fibers are randomly formed in the entire fiber mass, and the above-mentioned action effect by the fiber end portion is obtained. Is difficult to fully express.

From the viewpoint of more reliably exerting the action and effect of the fiber end portion described above, the number N1 per unit area of the fiber end portion of the basic surface 111 (non _- cut surface) and the skeleton surface 112 (cut surface). The ratio of the fiber end to the number N ₂ per unit area is N ₁ / N ₂ , preferably 0 or more, more preferably 0.05 or more, and preferably 0, assuming N ₁ <N ₂ . It is .90 or less, more preferably 0.60 or less. More specifically, N ₁ / N ₂ is preferably 0 or more and 0.90 or less, and more preferably 0.05 or more and 0.60 or more.
The number N ₁ per unit area of the fiber end of the basic surface 111 is preferably 0 pieces / mm ² or more, more preferably 3 pieces / mm ² or more, and preferably 8 pieces / mm ² or less, still more preferably. 6 pieces / mm ² or less.
The number N ₂ per unit area of the fiber end of the skeleton surface 112 is preferably 5 pieces / mm ² or more, more preferably 8 pieces / mm ² or more, and preferably 50 pieces / mm ² or less, still more preferably. 40 pieces / mm ² or less.
The number of fiber ends of the basic surface 111 and the skeleton surface 112 per unit area is measured by the following method.

<Measuring method of the number of fiber ends per unit area on each surface of the fiber mass>
A member (fiber mass) containing a fiber to be measured is attached to a sample table using a paper double-sided tape (Nichiban Co., Ltd. Nystack NW-15). The measurement piece is then platinum coated. For coating, an ion sputtering device E-1030 (trade name) manufactured by Hitachinaka Seiki Co., Ltd. is used, and the sputtering time is 120 seconds. The cut surface of the measurement piece is observed on the basic surface and the skeletal surface at a magnification of 100 times using a JCM-6000 type electron microscope manufactured by JEOL Ltd. In this observation screen with a magnification of 100 times, a rectangular area of 1.2 mm in length and 0.6 mm in width is set at an arbitrary position on the measurement target surface (basic surface or skeleton surface), and the area of the rectangular area is the said. After adjusting the observation angle and the like so as to occupy 90% or more of the area of the observation screen, the number of fiber ends contained in the rectangular region is measured. However, in the observation screen with a magnification of 100 times, when the measurement target surface of the fiber mass is smaller than 1.2 mm × 0.6 mm and the ratio of the area of the rectangular region to the entire observation screen is less than 90%. After increasing the observation magnification to more than 100 times, the number of fiber ends contained in the rectangular region on the measurement target surface is measured in the same manner as described above. Here, the "fiber end" to be counted is the end in the length direction of the constituent fibers of the fiber mass, and the portion other than the end in the length direction of the constituent fibers from the measurement target surface (intermediate in the length direction). Even if the part) is extended, the middle part in the length direction is not subject to the number measurement. Then, the number of fiber ends per unit area on the measurement target surface (basic surface or skeleton surface) of the fiber mass is calculated by the following formula. For each of the 10 fiber lumps, the number of fiber ends per unit area on each of the basic surface and the skeleton surface was measured according to the above procedure, and the average value of the plurality of measured values was calculated as the average value of the plurality of measured values. The number per unit area of.
Number of fiber ends per unit area on the measurement target surface (basic surface or skeleton surface) of the fiber mass (number / mm ² ) = number of fiber ends included in the rectangular region (1.2 × 0.6 mm) / Area of the rectangular area (0.72 mm ² )

When the basic surface 111 of the fiber mass 11 has a rectangular shape in a plan view as in the fiber mass 11A shown in FIG. 6A, from the viewpoint of improving the uniform dispersibility of the fiber mass 11 in the absorber 4. The rectangular short side 111a is preferably equal to or shorter than the thickness of the absorber 4 containing the fiber mass 11 (11A).
The ratio of the length of the short side 111a to the thickness of the absorber 4 is preferably 0 as the former / the latter.
It is 03 or more, more preferably 0.08 or more, and preferably 1 or less, still more preferably 0.5 or less.
The thickness of the absorber 4 is preferably 1 mm or more, more preferably 2 mm or more, and preferably 10 mm or less, still more preferably 6 mm or less. The thickness of the absorber 4 is measured by the following method.

<Measuring method of absorber thickness>
The object to be measured (absorbent 4) is placed on a horizontal surface so as not to be wrinkled or bent, and the thickness of the object to be measured is measured under a load of 5 cN / cm ² . Specifically, for measuring the thickness, for example, a thickness meter PEACOCK DIAL UPRIGHT GAUGES R5-C (manufactured by OZAKI MFG.CO.LTD.) Is used. At this time, a plan-viewing circular or square plate (thickness) whose size is adjusted so that the load on the measurement object is 5 cN / cm ² between the tip of the thickness gauge and the cut-out object to be measured. (Acrylic plate of about 5 mm) is placed and the thickness is measured. In the thickness measurement, 10 points are measured, and the average value thereof is calculated to obtain the thickness of the object to be measured.

It is preferable to set the dimensions and the like of each part of the fiber mass 11 (11A, 11B) as follows. The dimensions of each part of the fiber mass 11 can be measured based on an electron micrograph or the like at the time of specifying the outer shape of the fiber mass 11 described later.
When the basic surface 111 has a rectangular shape in a plan view as shown in FIG. 6A, the length L1 of the short side 111a is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm. The above, and preferably 10 mm or less, more preferably 6 mm or less, and particularly preferably 5 mm or less.
The length L2 of the long side 111b of the basic surface 111 having a rectangular shape in a plan view is preferably 0.3 mm or more, more preferably 1 mm or more, particularly preferably 2 mm or more, and preferably 30 mm or less, further preferably 15 mm or less. It is particularly preferably 10 mm or less.
As shown in FIG. 6, when the basic surface 111 is the surface having the maximum area among the plurality of surfaces of the fiber mass 11, the length L2 of the long side 111b is the maximum transfer length of the fiber mass 11. The maximum transfer length corresponds to the diameter of the basic surface 111 having a circular shape in a plan view in the disk-shaped fiber mass 11B.
The ratio of the length L1 of the short side 111a to the length L2 of the long side 111b is preferably 0.003 or more, more preferably 0.025 or more, and preferably 1 or less, more preferably 1 or less, as L1 / L2. It is 0.5 or less. In the present invention, the plan view shape of the basic surface 111 is not limited to the rectangular shape as shown in FIG. 6A, but may be a square shape, that is, the ratio of the lengths L1 and L2 of the two sides orthogonal to each other is , L1 / L2 may be 1.
The thickness T of the fiber mass 11, that is, the length T between the two opposing basic surfaces 111 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and preferably 10 mm or less, still more preferably 6 mm or less. be.

FIG. 8A shows an electron micrograph of an example of the fiber mass according to the present invention, and FIG. 8B shows a diagram schematically showing the fiber mass 11 according to the electron micrograph. Has been done. As shown in FIG. 8, the fiber mass 11 includes a main body portion 110 and fibers 11F extending outward from the main body portion 110, and has a lower fiber density (unit area) than the main body portion 110. Those having the extended fiber portion 113 (with a small number of per-fibers) can be included. The absorber 4 may also include a fiber mass 11 having no extended fiber portion 113, that is, a fiber mass 11 composed of only the main body portion 110. The extended fiber portion 113 may include a type of fiber end portion existing on each surface (basic surface 111, skeleton surface 112) of the fiber mass 11 described above, and is a fiber among the fiber end portions. It is a fiber end extending outward from each surface of the mass 11.

The main body portion 110 is a portion defined by the above-mentioned two facing basic surfaces 111 and a skeleton surface 112 connecting both basic surfaces 111. The main body 110 is a portion that forms the main body of the fiber mass 11 and forms a fixed outer shape of the fiber mass 11, and various characteristics such as high flexibility, cushioning property, and compression recovery property of the fiber mass 11 are basic. It is largely due to the main body 110. On the other hand, the extended fiber portion 113 mainly contributes to the improvement of the entanglement between the plurality of fiber lumps 11 contained in the absorber 4 or between the fiber lumps 11 and the water-absorbent fiber 12F, and the shape-retaining property of the absorber 4. In addition to being directly related to the improvement of the fiber mass 11, it can also affect the uniform dispersibility of the fiber mass 11 in the absorber 4 and indirectly reinforce the action and effect of the main body 110.

The main body portion 110 has a higher fiber density than the extended fiber portion 113, that is, the number of fibers per unit area is large. Further, usually, the fiber density of the main body 110 itself is uniform. The ratio of the main body 110 to the total mass of the fiber mass 11 is usually at least 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 85% by mass or more. The main body portion 110 and the extended fiber portion 113 can be distinguished from each other by the work of specifying the outer shape, which will be described later.

The work of specifying the outer shape of the main body 110 of the fiber mass 11 included in the absorber 4 is the work of specifying the height difference of the fiber density (the number of fibers per unit area) and the fiber in the fiber mass 11 and its peripheral portion. This can be done by checking the "boundary" between the main body 110 and the other parts, paying attention to the difference in type and fiber diameter. The main body portion 110 has a higher fiber density than the extended fiber portion 113 existing around the main body portion 110, and the synthetic fiber (typically thermoplastic fiber) which is a constituent fiber of the main body portion 110 is usually a water-absorbent fiber 12F (typically). Since it is qualitatively and / or dimensionally different from the cellulose-based fiber), even in the absorber 4 in which a large number of fiber lumps 11 and the water-absorbent fiber 12F are mixed, the above-mentioned points can be focused on. The boundaries can be easily confirmed. The boundary thus confirmed is the peripheral edge (side) of the basic surface 111 or the skeleton surface 112, and the basic surface 111 and the skeleton surface 112 are specified by such boundary confirmation work, and the main body portion 110 is specified. Will be done. Such boundary confirmation work can be carried out by observing the object (absorbent 4) at a plurality of observation angles as needed using an electron microscope.

As shown in FIG. 8, at least one extension fiber portion 113 exists around the main body portion 110, and is outward from at least one of the basic surface 111 and the skeleton surface 112, which are the outer surfaces of the main body portion 110. It is composed of the constituent fibers 11F of the main body 110 extending to. In the fiber mass 11 shown in FIG. 8, a plurality of constituent fibers 11F protrude outward from the four sides 112a and 112b of the rectangular skeleton surface 112 in a plan view, and the fibers protrude from the main body 110. All the portions are extended fiber portions 113.

The form of the extended fiber portion 113 is not particularly limited. The extended fiber portion 113 may be composed of one fiber 11F, or may be composed of a plurality of fibers 11F as in the extended fiber bundle portion 113S described later. Further, the extended fiber portion 113 typically includes an end portion in the length direction of the fiber 11F extending from the main body portion 110, but in addition to or in place of such a fiber end portion, In some cases, a portion (intermediate portion in the length direction) other than both ends in the length direction of the fiber F may be included. That is, in the fiber mass 11, both ends of the constituent fibers 11F in the length direction exist in the main body portion 110, and the other parts, that is, the intermediate portions in the length direction extend outward from the main body portion 110 in a loop shape ( Where there is a case of protrusion), the extending fiber portion 113 in that case is configured to include such a loop-shaped protruding portion of the fiber 11F. In other words, of the extended fiber portions 113, those whose ends are exposed are one type of fiber end portions.

As described above, one of the main roles of the extended fiber portion 113 is to entangle the plurality of fiber lumps 11 contained in the absorber 4 with each other, or the fiber lumps 11 and the water-absorbent fiber 12F. Generally, the extension length of the extension fiber portion 113 from the main body portion 110 becomes longer, the thickness of the extension fiber portion 113 becomes thicker, or the number of extension fiber portions 113 contained in one fiber mass 11. When the amount of entanglement increases, the connection between the entangled objects via the extended fiber portion 113 becomes stronger and the entanglement becomes difficult to be released, so that the predetermined effect of the present invention can be more stably achieved. Become.

When the fiber mass 11 is obtained by cutting the raw material fiber sheet 10bs into a fixed shape as shown in FIG. 7, the extended fiber portion 113 is present in a relatively large amount on the skeleton surface 112 which is the cut surface thereof. On the other hand, it does not exist at all on the basic surface 111, which is a non-cut surface, or even if it exists, the number is smaller than that of the skeletal surface 112. As described above, the reason why the extended fiber portion 113 is unevenly distributed on the skeleton surface 112 which is the cut surface is that most of the extended fiber portion 113 is "fluff" generated by cutting the raw material fiber sheet. That is, since the skeleton surface 112 formed by cutting the raw material fiber sheet 10bs is entirely rubbed by a cutting means such as a cutter at the time of cutting, fluff made of the constituent fibers 11F of the sheet 10bs is likely to be formed, so-called fluffing. easy. On the other hand, since the basic surface 111, which is a non-cut surface, does not have friction with such a cutting means, it is difficult to form fluff, that is, the extended fiber portion 113.

The interval L1a (interval in the first direction, see FIG. 7) and the interval L2a (interval in the second direction, see FIG. 7) at the time of cutting the raw material fiber sheet 10bs are used to promote the formation of the extended fiber portion 113 described above. From the viewpoint of ensuring the dimensions necessary for the fiber lump 11 to exert a predetermined effect, preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 30 mm or less, still more preferable. Is 15 mm or less.

As shown in FIG. 8, the fiber mass 11 includes an extended fiber bundle portion 113S including a main body portion 110, more specifically, a plurality of fibers 11F extending outward from the skeleton surface 112 as a kind of extended fiber portion 113. What you have can be included. At least one of the extended fiber portions 113 included in the fiber mass 11 may be the extended fiber bundle portion 113S. The extended fiber bundle portion 113S is formed by gathering a plurality of fibers 11F extending from the skeleton surface 112, and has an extension length from the main body portion 110 skeleton surface 112 as compared with the extended fiber portion 113. Is characterized by a long point. The extended fiber bundle portion 113S may also be present on the basic surface 111, but is typically present on the skeletal surface 112 as shown in FIG. 8, and is not present at all on the basic surface 111, or even if it is present. The number is less than the skeletal surface 112. The reason is the same as the reason why the extended fiber portion 113 mainly exists on the skeleton surface 112 which is the cut surface, and is as described above.

Since the fiber mass 11 has such an extended fiber bundle portion 113S which can be said to be a long, thick and large extended fiber portion 113, the fiber masses 11 or the fiber mass 11 and the water-absorbent fiber 12F can be connected to each other. The entanglement becomes stronger, and as a result, the predetermined effect of the present invention due to the presence of the fiber lump 11 becomes more stable. The extended fiber bundle portion 113S is easily formed by performing the above-mentioned cutting of the raw material fiber sheet 10bs under the condition of easy fluffing (see FIG. 7).

The extension length of the extension fiber bundle portion 113S from the main body portion 110, that is, the extension length from the skeleton surface 112 (cut surface) is preferably 0.2 mm or more, more preferably 0.5 mm or more, and It is preferably 7 mm or less, more preferably 4 mm or less. The extension length of the extension fiber bundle portion 113S can be measured in the work of specifying the outer shape of the fiber mass 11 (boundary confirmation work). Specifically, for example, a double-sided tape manufactured by 3M Co., Ltd. was attached to the surface of a transparent sample table made of acrylic with a KEYENCE microscope (50 magnification), and a fiber mass 11 was placed and fixed on the double-sided tape. Above, after specifying the outer shape of the fiber mass 11 according to the above-mentioned work of specifying the outer shape, the length of the extended portion of the fiber 11F extending from the outer shape is measured, and the measured extension is measured. The length of the minute is defined as the extension length of the extension fiber bundle portion 113S.

It is preferable that the plurality of constituent fibers 11F of the extended fiber bundle portion 113S are heat-sealed to each other. The heat-sealed portion of the extended fiber bundle portion 113S is usually in the length direction of the extended fiber bundle portion 113S as compared with other portions (non-heat-fused portions) of the extended fiber bundle portion 113S. The transfer length (diameter when the cross section of the heat-sealed portion is circular) is long in the direction orthogonal to. Since the extended fiber bundle portion 113S has such a heat-sealed portion that can be said to be a large-diameter portion, the strength of the extended fiber bundle portion 113S itself is increased, thereby passing through the extended fiber bundle portion 113S. The entanglement between the entangled fiber lumps 11 or between the fiber lumps 11 and the water-absorbent fiber 12F becomes stronger. Further, when the extended fiber bundle portion 113S has a heat-sealed portion, not only when the extended fiber bundle portion 113S is in a dry state but also when it is in a wet state by absorbing moisture. There is an advantage that the strength and shape retention of the extended fiber bundle portion 113S itself are enhanced. Due to such merits, when the absorber 4 is applied to the napkin 1, it absorbs body fluids such as urine and menstrual blood excreted by the wearer as well as when the absorber 4 is in a dry state. Even in a wet state, the action and effect due to the presence of the above-mentioned fiber mass 11 can be stably exerted. Such an extended fiber bundle portion 113S having a heat-sealed portion is used as the raw material fiber sheet 10bs in the manufacturing process of the fiber mass 11 as shown in FIG. 7, that is, the cutting step of the raw material fiber sheet 10bs of the fiber mass 11. It can be manufactured by using the above-mentioned "nonwoven fabric having a heat-sealed portion between synthetic fibers".

Further, it is preferable that the fiber mass 11 is densely and uniformly distributed in the entire absorber 4 because the responsiveness to an external force tends to have isotropic property. From such a viewpoint, it is preferable that the overlapping portion of the plurality of fiber lumps 11 is present in an arbitrary 10 mm square unit region in the projection view of the absorber 4 in two directions orthogonal to each other. Reference numerals 11Z in FIGS. 3 and 4 indicate overlapping portions of the plurality of fiber lumps 11. The term "projection view in two directions orthogonal to each other" as used herein is typically referred to as projection view in the thickness direction of the absorber (that is, when the absorber is observed from its skin-facing surface or non-skin-facing surface). , Projection view in a direction orthogonal to the thickness direction (that is, when the absorber is observed from the side surface).

Synthetic fibers are used as the constituent fibers 11F of the fiber mass 11. Then, from the viewpoint of enabling the absorber 4 to exhibit excellent effects in shape retention, flexibility, cushioning property, compression recovery property, resistance to twisting, etc. in both a dry state and a wet state, a fiber mass is formed. 11 preferably has a three-dimensional structure in which a plurality of thermoplastic fibers are heat-fused together. Further, in order to obtain such a fiber mass 11 in which a plurality of heat-sealed portions are three-dimensionally dispersed, a synthetic fiber having heat-sealing property is preferable as the constituent fiber 11F of the fiber mass 11. As such a heat-fusing synthetic fiber, a thermoplastic fiber can be exemplified, and a non-water-absorbent thermoplastic fiber is particularly preferable. As described above, it is preferable that the extended fiber bundle portion 113S has a heat-sealed portion. However, by using a thermoplastic fiber as the constituent fiber 11F of the fiber mass 11, the extended fiber bundle portion 113S is used. It is also possible to obtain a preferable form of. In order to obtain a fiber mass 11 in which a plurality of heat-sealed portions are three-dimensionally dispersed, the raw material fiber sheets 10bs (see FIG. 7) may be similarly configured, and such a plurality of heats may be obtained. As described above, the raw material fiber sheet 10bs in which the fused portions are three-dimensionally dispersed can be manufactured by subjecting a web or a non-woven fabric mainly composed of thermoplastic fibers to a heat treatment such as hot air treatment.

Examples of the non-water-absorbent thermoplastic resin suitable as a material for the constituent fibers 11F of the fiber mass 11 include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyvinylidene acid, and the like. Examples thereof include polymethacrylic acid alkyl esters, polyvinyl chloride, polyvinylidene chloride and the like, and one of these can be used alone or in combination of two or more. The fiber 11F may be a single fiber made of one kind of synthetic resin (thermoplastic resin) or a blend polymer in which two or more kinds of synthetic resins are mixed, or may be a composite fiber. The composite fiber referred to here is a synthetic fiber (thermoplastic fiber) obtained by compounding two or more kinds of synthetic resins having different components with a spinneret and spinning them at the same time, and a plurality of components are continuous in the length direction of the fiber. A structure that is mutually bonded within a single fiber. The form of the composite fiber includes a core sheath type, a side-by-side type, and the like, and is not particularly limited.

In the absorber 4, rapid diffusion of body fluid due to the density difference between the recessed portion 7 which is a relatively high density portion and the non-recessed portion 8 which is a relatively low density portion is effectively exhibited, and From the viewpoint of exhibiting a flexible and cushioning effect of the non-recessed portion 8 not only in a dry state before body fluid absorption but also in a wet state after body fluid absorption, the constituent fibers 11F (synthetic fiber 11F) of the fiber mass 11 are exhibited. ) With water, it is preferable that the contact angle with water of the water-absorbent fiber 12F or more is equal to or greater than the contact angle with water. The smaller the contact angle with water measured by the following method, the higher the hydrophilicity, and the larger the contact angle, the lower the hydrophilicity. That is, it is preferable that the hydrophilicity of the synthetic fiber 11F is equal to or lower than the hydrophilicity of the water-absorbent fiber 12F. On the premise of this, the contact angle of the water-absorbent fiber 12F with water is preferably 60 degrees or less, more preferably 40 degrees or less. On the other hand, the contact angle of the constituent fibers 11F of the fiber mass 11 with water is 90 degrees or less, preferably 75 degrees or less, and more preferably 70 degrees or less. In order to realize the relationship of "fiber 11F ≥ water-absorbent fiber 12F" with respect to the contact angle with water as described above, the degree of hydrophilization of the fiber 11F by the hydrophilizing agent may be appropriately adjusted.

<Measurement method of contact angle>
The fiber is taken out from the measurement target (absorber), and the contact angle of water with respect to the fiber is measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Deionized water is used to measure the contact angle. The amount of liquid discharged from the inkjet water droplet discharge unit (Pulse injector CTC-25 manufactured by Cluster Technology Co., Ltd., having a discharge unit hole diameter of 25 μm) is set to 20 picolitres, and the water droplet is dropped directly above the fiber. The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. From the viewpoint of image analysis later, the recording device is preferably a personal computer incorporating a high-speed capture device. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of water droplets on the fibers is the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2, image processing algorithm. Is non-reflective, the image processing image mode is frame, the threshold level is 200, and the curvature is not corrected.) Make a corner. The fiber taken out from the object to be measured is cut into a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and maintained horizontally. Measure the contact angles at two different points for each fiber. N = 5 contact angles are measured up to one digit after the decimal point, and the average value of the measured values at 10 points in total (rounded to the second digit after the decimal point) is defined as the contact angle of the fiber with water. The measurement environment is room temperature 22 ± 2 ° C. and humidity 65 ± 2% RH.

The absorber (absorbent core) to be measured is used as a constituent member of another article such as an absorbent article, and when the absorber is taken out and evaluated and measured, the absorber is an adhesive. When it is fixed to other components by fusion, etc., the adhesive force is removed from the fixed part by blowing cold air from a cold spray within the range that does not affect the contact angle of the fibers. Take out from. This procedure is common to all measurements herein.

As the water-absorbent fiber 12F, water-absorbent fiber conventionally used as a material for forming an absorber of this kind of absorbent article can be used. For example, wood pulp such as coniferous pulp and broadleaf pulp, cotton pulp and hemp. Natural fibers such as non-wood pulp such as pulp; Modified pulp such as cationized pulp and marcelled pulp; Regenerated fiber such as cupra and rayon; Semi-synthetic fiber such as acetate; Hydrophilic synthesis such as polyvinyl alcohol fiber and polyacrylonitrile fiber Fibers; Examples thereof include fibers obtained by subjecting synthetic fibers such as polyethylene terephthalate fiber, polyethylene fiber, polypropylene fiber, and polyester fiber to a hydrophilic treatment, and one of these can be used alone or in combination of two or more. .. The hydrophilization treatment of the synthetic fiber includes, for example, kneading of the hydrophilizing agent inside the synthetic fiber, adhesion of the hydrophilizing agent to the surface of the synthetic fiber, plasma treatment, and the like. The hydrophilizing agent is not particularly limited as long as it is a general hydrophilizing agent used for hygienic products.
As described above, natural fibers and regenerated fibers (cellulose fibers) are particularly preferable as the water-absorbent fibers 12F in view of the fact that the main role of the water-absorbent fibers 12F is to improve the liquid absorbency of the absorber 4.

Further, it is preferable that the constituent fibers 11F constituting the fiber mass 11 have a non-water-absorbing property, that is, a property that it is difficult to absorb water (body fluid such as urine or menstrual blood). This is in stark contrast to the water-absorbent fiber 12F used in combination with the fiber mass 11 which literally has water absorbency. Since the fiber 11F is a non-water-absorbent fiber having poor water absorption, it is caused by the presence of the above-mentioned fiber mass 11 not only when the absorber 4 is in a dry state but also when it is in a wet state by absorbing body fluid. The action and effect (improvement effect such as shape retention, flexibility, cushioning property, compression recovery property, and resistance to twisting) will be stably exerted. Therefore, the raw material fiber is preferably a non-water-absorbent synthetic fiber.

As used herein, the term "water-absorbent" is easily understood by those of skill in the art, for example, pulp is said to be water-absorbent. Similarly, it can be easily understood that thermoplastic fibers are non-absorbent. On the other hand, the degree of water absorption of the fiber can be compared with the relative difference in water absorption by the value of the water content measured by the following method, and a more preferable range can be defined. As the water-absorbent fiber, the water content is preferably 6% or more, and more preferably 10% or more. On the other hand, the non-water-absorbent fiber preferably has such a water content of less than 6%, more preferably less than 4%.

<Measurement method of moisture content>
The water content was calculated by applying the water content test method of JIS P8203 mutatis mutandis. That is, after the fiber sample was allowed to stand in a test room having a temperature of 40 ° C. and a relative humidity of 80% RH for 24 hours, the weight W (g) of the fiber sample before the absolute drying treatment was measured in the room. Then, it was allowed to stand for 1 hour in an electric dryer having a temperature of 105 ± 2 ° C. (for example, manufactured by Isuzu Seisakusho Co., Ltd.) to dry out the fiber sample. After the absolute drying treatment, Si silica gel (for example, Si silica gel (for example,) in a state where the fiber sample is covered with Saran Wrap (registered trademark) manufactured by Asahi Kasei Corporation in a test room in a standard state with a temperature of 20 ± 2 ° C. and a relative temperature of 65 ± 2%. Toyoda Kako Co., Ltd. is placed in a glass desigator (for example, manufactured by Tech Jam Co., Ltd.) and allowed to stand until the temperature of the fiber sample reaches 20 ± 2 ° C. Then, the constant amount W'(g) of the fiber sample is weighed, and the water content of the fiber sample is obtained by the following formula. Moisture content (%) = (W-W'/ W') x 100

In the absorber 4, the content mass ratio of the fiber mass 11 and the water-absorbent fiber 12F is not particularly limited, and may be appropriately adjusted according to the types of the constituent fibers (synthetic fiber) 11F and the water-absorbent fiber 12F of the fiber mass 11. good. From the viewpoint of ensuring that the predetermined effect of the present invention is more reliably achieved, the content mass ratio of the fiber mass 11 and the water-absorbent fiber 12F is preferably the former (fiber mass 11) / the latter (water-absorbent fiber 12F). Is 20/80 to 80/20, more preferably 40/60 to 60/40.

The basis weight of the fiber mass 11 in the absorber 4 is preferably 32 g / m ² or more, more preferably 80 g / m ² or more, and preferably 640 g / m ² or less, still more preferably 480 g / m ² or less.
The basis weight of the water-absorbent fiber 12F in the absorber 4 is preferably 32 g / m ² or more, more preferably 80 g / m ² or more, and preferably 640 g / m ² or less, still more preferably 480 g / m ² or less. ..

The absorber 4 may contain other components other than the fiber mass 11 and the water-absorbent fiber 12F, and a water-absorbent polymer can be exemplified as the other component. As the water-absorbent polymer, a particulate polymer is generally used, but a fibrous polymer may also be used. When a particulate superabsorbent polymer is used, its shape may be spherical, lumpy, bale-shaped or amorphous. The average particle size of the water-absorbent polymer is preferably 10 μm or more, more preferably 100 μm or more, and preferably 100.
It is 0 μm or less, more preferably 800 μm or less. As the water-absorbent polymer, a polymer or copolymer of acrylic acid or an alkali metal salt of acrylic acid can generally be used. Examples thereof include polyacrylic acid and salts thereof, and polymethacrylic acid and salts thereof.

The content of the water-absorbent polymer in the absorber 4 is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 60% by mass or less, based on the total mass of the dry absorber 4. It is preferably 40% by mass or less.
The basis weight of the water-absorbent polymer in the absorber 4 is preferably 10 g / m ² or more, more preferably 30 g / m ² or more, and preferably 100 g / m ² or less, still more preferably 70 g / m ² or less.

The basis weight of the absorber 4 can be appropriately adjusted in consideration of the usage state of the absorbent article, but is preferably 100 g / m ² or more, more preferably 150 g / m ² or more, and preferably 800 g / m /. It is m ² or less, more preferably 750 g / m ² or less.

The absorber 4 having the above-mentioned configuration is flexible and has excellent cushioning properties, is also excellent in compression recovery property, deforms with good responsiveness to an external force, and quickly returns to the original state when the external force is released. The characteristics of such an absorber can be evaluated using the compression work amount (WC) and the compression recovery rate (RC) as measures. The amount of compression work is a measure of the cushioning property of the absorber, and it can be evaluated that the larger the WC value is, the higher the cushioning property is. The compression recovery rate is a measure showing the degree of recovery when the absorber is compressed and the compressed state is released, and it can be evaluated that the larger the RC value, the higher the compression recovery. Further, considering the role of the absorber 4 in absorbing and holding the liquid, the absorber 4 has a large WC value and RC value not only in a dry state but also in a wet state by absorbing body fluid or the like. Is preferable. In order for the absorber 4 to have such characteristics in a wet state, it is effective to use non-water-absorbent fibers such as thermoplastic fibers as the constituent fibers (synthetic fibers) 11F of the fiber mass 11 as described above. ..

The compression work (d-WC) of the non-recessed portion 8 of the absorber 4 in a dry state is preferably 25 mN · cm / cm ² or more, more preferably 29 mN · cm / cm ² or more, and preferably 80 mN ·. It is cm / cm ² or less, more preferably 70 mN · cm / cm ² or less.
The compression work (w-WC) of the non-recessed portion 8 of the absorber 4 in a wet state is preferably 25 mN · cm / cm ² or more, more preferably 29 mN · cm / cm ² or more, and preferably 80 mN ·. It is cm / cm ² or less, more preferably 70 mN · cm / cm ² or less.

The compression recovery rate (d-RC) of the non-recessed portion 8 of the absorber 4 in a dry state is preferably 30% or more, more preferably 40% or more, and preferably 75% or less, further preferably 65% or less. Is.
The compression recovery rate (w-RC) of the non-recessed portion 8 of the absorber 4 in a wet state is preferably 30% or more, more preferably 40% or more, and preferably 75% or less, further preferably 65% or less. Is.

<Measurement method of compression work (WC) and compression recovery rate (RC)>
It is generally known that the compression work (WC) and compression recovery rate (RC) of the absorber 4 can be expressed by the measured values by KES (Kawabata Evaluation System) manufactured by Katou Tech Co., Ltd. (Reference: Standardization and analysis of texture evaluation (2nd edition), author Kiyo Kawabata, published on July 10, 1980). Specifically, the compression work amount and the compression recovery rate can be measured by using the automated compression test apparatus KES-FB3-AUTO-A manufactured by Kato Tech Co., Ltd. The measurement procedure is as follows.
A 195 mm × 68 mm rectangular sample in plan view (absorbent not wrapped in a core wrap sheet, that is, an absorbent core) is prepared and attached to the test table of the compression test device. Next, the non-recessed portion of the sample, that is, the portion that has not been squeezed and the original shape of the sample remains, is compressed between the steel plates having a circular plane with an area of 2 cm ² . The compression rate is 0.01 cm / sec, and the maximum compression load is 490.2 mN / cm ² . The recovery process is also measured at the same speed. The compression work (WC) is expressed by the following equation. In the formula, T _m , To and P are the thickness under a load of 490.2 mN / cm ^{2 (4.9 kPa), 4.902 mN / cm 2} ₍ ⁴⁹ Pa), and the load at the time of measurement (mN), respectively. / Cm ² ) is shown.
The compression recovery rate (RC) is the ratio of the compression work amount (WC) at the time of compression and the compression work amount (WC') when the compressed state is restored to the original state [WC'/ WC). ] × 100.

The absorber 4 can be manufactured in the same manner as the absorber containing this kind of fiber material. As described above, the fiber mass 11 is a raw material fiber sheet (a sheet having the same composition as the fiber mass 11 and having a larger size than the fiber mass 11) as a raw material, using a cutting means such as a cutter. , Can be manufactured by cutting in two directions intersecting (orthogonal) with each other, and the plurality of fiber lumps 11 thus manufactured are "standard fiber aggregates" having uniform shapes and dimensions (for example, a main body portion). 110 is a rectangular parallelepiped shape). The absorber 4 including the fiber lump 11 and the water-absorbent fiber 12F can be manufactured according to a conventional method using, for example, a known fiber stacking device equipped with a rotating drum. Such a fiber stacking device typically conveys a rotary drum having an accumulation recess formed on the outer peripheral surface and raw materials (fiber mass 11, water-absorbent fiber 12F) of the absorbent core 40 to the accumulation recess. It is provided with a duct having a flow path inside, and while rotating the rotating drum around a rotation axis along the circumferential direction of the drum, an air flow (vacuum) generated in the flow path by suction from the inside side of the rotating drum. The raw materials transported on the air) are made to be stacked in the accumulation recesses. The fiber stack formed in the accumulation recess by the fiber stacking process is the absorbent core 40.

Although the present invention has been described above based on the embodiment, the present invention can be appropriately modified without being limited to the embodiment.
For example, in the absorbent core according to the present invention, the fiber lumps may not be uniformly dispersed throughout the absorbent core, or may be unevenly distributed. As a form in which the fiber mass is unevenly distributed, an absorbent core having a laminated structure of a layer mainly composed of the fiber mass and a layer mainly composed of the water-absorbent fiber can be exemplified.
Further, in the absorbent core according to the present invention, all of the fiber lumps (synthetic fiber aggregates) contained therein do not have to be a fixed-shaped fiber aggregate such as the fiber lump 11, which deviates from the gist of the present invention. As long as it does not, a very small amount of atypical fiber aggregates may be contained in addition to the fixed-form fiber aggregates.
The absorbent article of the present invention broadly includes articles used for absorbing body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body, and in addition to the above-mentioned sanitary napkins, sanitary shorts and fastenings. So-called deployable disposable diapers with tape, pants-type disposable diapers, incontinence pads and the like are included.

1,1A Sanitary napkin (absorbent article)
A Front area B Vertical center area C Rear area 2 Front sheet 3 Back sheet 4 Absorber 40 Absorbent core 11 Fiber mass 11F Fiber mass constituent fibers (synthetic fiber)
110 Main body 111 Basic surface 112 Skeleton surface 113 Extended fiber part 113S Extended fiber bundle part 12F Water-absorbent fiber 41 Core wrap sheet 5 Absorbent main body 6 Side sheet 7 Recessed part 7X Vertical concave part 7Y Horizontal concave part 10bs Raw fiber sheet

Claims (5)

It has a vertical direction corresponding to the front-back direction of the wearer and a horizontal direction orthogonal to the vertical direction, and in the vertical direction, a vertical central region including an excretory portion facing portion facing the wearer's excretory portion, and the excretory portion facing portion. It is divided into an anterior region located on the ventral side of the wearer and a posterior region located on the dorsal side of the wearer rather than the excretory portion facing portion. An absorbent article comprising an absorbent body, including an arranged surface sheet.
The absorber includes a fiber mass containing a plurality of synthetic fibers and a water-absorbent fiber.
A recessed portion in which the surface sheet and the absorber are integrally recessed on the non-skin facing surface side of the absorber is partially formed in the absorbent body, and the recessed portion is formed in the recessed portion in the absorbent body. The density is higher than that of the non-recessed part, which is the part where the part is not formed.
In the absorber in the non-recessed portion, the plurality of fiber lumps are entangled with each other without being fused .
The fiber mass comprises two opposing basic surfaces and a skeletal surface connecting the two basic surfaces.
An absorbent article in which the number of fiber ends present on each of the basic surface and the skeletal surface per unit area is larger in the skeletal surface than in the basic surface . The absorbent article according to claim 1, wherein the recessed portion is present in the front region and the rear region, and the non-recessed portion is present in the vertical center region. The absorbent article according to claim 1 or 2, wherein the non-recessed portion is present in the lateral central portion of the vertical central region, and the concave portion is present on both sides in the lateral direction across the non-recessed portion. The absorbent article according to any one of claims 1 to 3 , wherein the fiber mass comprises an extended fiber bundle portion including a plurality of fibers extending outward from the skeleton surface. The absorbent article according to any one of claims 1 to 4 , wherein the content mass ratio of the fiber mass to the water-absorbent fiber is 20/80 to 80/20 as the former / the latter.

Images