JP2019097612A - Absorbent article - Google Patents

Abstract

To provide an absorbent article in which, a folding wrinkle hardly occurs in folding time.SOLUTION: An absorbent article 1 of the invention comprises: an absorber 4 including an absorbent core 40; and a surface sheet 2 arranged on a skin facing surface side of the absorber 4. The absorbent core 40 comprises: fiber masses 11 including synthetic fibers 11F and hydrophilic fibers 12F, the fiber masses 11 or the fiber mass 11 and the hydrophilic fiber 12F are intertwined. The fiber mass 11 comprises: two facing basic surfaces 111; and a skeleton surface 112 for connecting two basic surfaces 111. A folding line 8 extends in a prescribed direction on a skin facing surface of the surface sheet 2, and on a part overlapped to the folding line 8 in a thickness direction on the absorbent core 40, there are a folding line striding fiber mass 11S which strides the folding line 8 in a direction crossing the extension direction of the folding line and a part where, the fiber masses 11 are not fused.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an absorbent article such as a sanitary napkin, and more particularly to an absorbent article provided with a surface sheet having a plurality of convex portions formed on the surface facing the skin.

  Absorbent articles such as disposable diapers and sanitary napkins are generally sold in the form of being folded so that the side in contact with the skin of the wearer is inside.

  In the individual package of the absorbent article, the applicant of the present invention has a circumferential leak-proof groove extending in the longitudinal direction that integrates the surface sheet and the absorber, and the left and right grooves constituting the circumferential leak-proof groove. When the individual package folding line is unwound by arranging the individual folding line of the individual package at a specific position between the circumferential leakage preventing groove and the central groove by providing a laterally extending central groove It was proposed that it becomes difficult to get wrinkles in the part of the surface sheet corresponding to the part which was being bent in the absorbent article (patent document 1).

  Apart from this, as an improvement technique of the absorber, for example, Patent Document 2 discloses an absorber comprising a thermoplastic resin fiber and a cellulose-based water-absorbing fiber, wherein the thermoplastic resin fiber is What is exposed to both the surface on the surface sheet side and the surface on the back sheet side of the absorber is described. According to the absorbent body described in Patent Document 1, the thermoplastic resin fiber functions as a skeleton for holding other components of the absorbent body such as a cellulose-based water-absorbent fiber, and therefore, is considered to be soft and difficult to twist. .

  Further, Patent Document 3 describes an absorbent containing a non-woven fabric piece to which a three-dimensional structure has been imparted by bonding between fibers in advance, which contains heat-fusion fibers, and a hydrophilic fiber. The non-woven fabric piece of this 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 due to such a manufacturing method, FIGS. It has an irregular shape as described in 3, and has substantially no part that can be regarded as a flat surface.

  Further, Patent Document 4 describes a fine web having relatively dense fine fiber cores and fibers or fiber bundles extending outward from the core, and the fine web and wood pulp or a water absorbing polymer. It is described that non-woven webs mixed with particles can be used as an absorbent for absorbent articles. This fine web is manufactured by peeling off or tearing off a raw material sheet such as non-woven fabric, and like the non-woven fabric piece described in Patent Document 3, it has an irregular shape and a portion which can be regarded as a flat surface It does not have substantially.

JP, 2010-178932, A JP, 2015-16296, A JP 2002-301105 A Unexamined-Japanese-Patent No. 1-156560

When an absorbent article such as a sanitary napkin is developed from being folded in an individual package, there has been a problem that the top sheet folds along the folding line at the time of folding. If the skin-facing surface of the absorbent article is wrinkled, it may lead to discomfort when worn, and there may be leakage of excrement fluid due to the absorbent article being difficult to adhere to the wearer's skin at the fold. is there. In the technique disclosed in Patent Document 1, the improvement of the compromise may be insufficient at the time of long-term storage. The patent documents 2 to 4 do not describe anything about the subject of such a fold, and the technique which can solve such a subject is not provided yet.

  An object of the present invention relates to providing an absorbent article that is resistant to folding during folding.

  The present invention comprises an absorbent body including an absorbent core, and a surface sheet disposed on the skin-facing surface side of the absorbent body, and a longitudinal direction corresponding to the front-rear direction of the wearer and a transverse direction orthogonal thereto An absorbent article, wherein the absorbent core contains a fiber mass containing a synthetic fiber and a hydrophilic fiber, and the fiber mass or the fiber mass and the hydrophilic fiber are entangled, The fiber mass comprises two opposing basic surfaces and a skeletal surface connecting the two basic surfaces, and the absorbent article is folded on the skin-facing surface of the surface sheet with the surface sheet inside. A fold line used in the case extends in a predetermined direction, and a fold line crossing the fold line in a direction intersecting the extension direction is formed in a portion of the absorbent core overlapping in the thickness direction with the fold line. A fiber mass is present, and a portion where the fiber mass is not fused is present. Is a sex articles.

  The absorbent article of the present invention is less likely to have folds due to individual packaging, so that the discomfort when worn due to folds is reduced, and the absorbent article is in close contact with the skin of the wearer when worn and is less likely to leak.

FIG. 1 is a plan view schematically showing a skin facing surface side (surface sheet side) of an example of a sanitary napkin which is an embodiment of the absorbent article according to the present invention with a part broken. FIG. 2 is a cross-sectional view schematically showing a cross section taken along the folding line (first folding line) of FIG. FIG. 3 is a schematic perspective view of the unit body of the sanitary napkin shown in FIG. FIG. 4 is a longitudinal sectional view schematically showing a section taken along the longitudinal direction of the sanitary napkin shown in FIG. FIG. 5 (a) and FIG. 5 (b) are each a schematic perspective view of a fiber mass according to the present invention. FIG. 6 is an explanatory view of a method of producing a fiber mass according to the present invention. FIG. 7 is an explanatory view of the positional relationship between the bending line and the fiber mass, and FIGS. 7 (a) and 7 (b) are configurations within the scope of the present invention, and FIGS. 7 (c) and 7 (d). Is a form outside the scope of the present invention.

  Hereinafter, the absorbent article of the present invention will be described based on its preferred embodiments with reference to the drawings. The sanitary napkin 1 which is one Embodiment of the absorbent article of this invention is shown by FIG.1 and FIG.2. The napkin 1 comprises an absorbent body 4 including an absorbent core 40 and a surface sheet 2 disposed on the skin-facing surface side of the absorbent body 4, and the crotch is interposed from the front and rear direction of the wearer, that is, from the ventral side. And a longitudinal direction X corresponding to the direction extending to the dorsal side, and a transverse direction Y orthogonal to the longitudinal direction.

In the present specification, the "skin-facing surface" is a surface of an absorbent article or a component thereof (for example, a surface sheet) that is directed to the skin side of the wearer when wearing the absorbent article, ie, the relative skin of the wearer. And the “non-skin facing surface” is the surface of the absorbent article or component thereof that faces away from the skin when the absorbent article is worn, ie, relatively away from the wearer's skin It is the side. In addition, "at the time of wear" here means the state in which the normal proper wearing position, ie, the correct wearing position of the said absorbent article, was maintained.

  As shown in FIG. 1, the napkin 1 has a longitudinal central area B including an excretory part opposing part (excretion point) facing the excretory part such as the vaginal opening of the wearer in the longitudinal direction X, and the excretory part opposing part Also, it is divided into three, a front area A disposed on the ventral side (front side) of the wearer, and a rear area C disposed on the back side (rear side) of the wearer than the excretory part facing portion. In addition, the napkin 1 has a pair of wings extending outward in the transverse direction Y from the absorbent main body 5 having a shape long in the longitudinal direction X and both sides along the longitudinal direction X of the longitudinal central region B in the absorbent main body 5. And 5W. The absorbent main body 5 is a main part of the napkin 1 and includes the front sheet 2, the back sheet 3 and the absorbent body 4 described above, and in the longitudinal direction X, the front area A, the longitudinal central area B and the rear area C It is divided into three.

  When the absorbent article has wings as in the case of the napkin 1, the longitudinal central area in the absorbent article of the present invention is a wing in the longitudinal direction (longitudinal direction, X direction in the figure) of the absorbent article. When the napkin 1 is taken as an example, it means an area sandwiched between a base along the longitudinal direction X of one wing 5W and a base along the longitudinal direction X of the other wing 5W. Moreover, the excretion part facing part in the absorbent article which does not have a wing part is used when folding an absorbent article in the individual form of a three-fold, this absorbent article is transverse direction (width direction, Y in the figure 1), the front end in the longitudinal direction of the absorbent article, that is, the ventral side of the wearer among the longitudinal ends of the absorbent article. It means the area surrounded by the first fold and the second fold, counting from the longitudinal end arranged in.

  In the napkin 1, the absorbent body 4 is configured to include a liquid absorbent absorbent core 40 and a liquid permeable core wrap sheet 41 that covers the outer surface of the absorbent core 40. The absorbent core 40 has a long shape in the longitudinal direction X in plan view as shown in FIG. 1 like the absorbent main body 5, and the longitudinal direction of the absorbent core 40 is one in the longitudinal direction X of the napkin 1. 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 joined by an adhesive such as a hot melt adhesive.

  In the napkin 1, the core wrap sheet 41 is one continuous sheet having a width twice to three times the length of the absorbent core 40 in the transverse direction Y, and as shown in FIG. The entire surface of the elastic core 40 facing the skin is covered, and extends outward from both side edges along the longitudinal direction X of the absorbent core 40 in the lateral direction Y, and the extended portion 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 may not be such a single sheet, for example, one skin side core wrap sheet for covering the skin facing surface of the absorbent core 40, and the skin side. The core wrap sheet may be separate from the core wrap sheet, and may include two sheets with 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 top sheet 2 covers the entire area of the skin facing surface of the absorber 4. On the other hand, the back sheet 3 covers the whole area of the non-skin facing surface of the absorbent body 4 and extends outward from both side edges along the longitudinal direction X of the absorbent body 4 in the lateral direction Y, together with side sheets 6 described later It forms a side flap. The side flap portion is a portion of the napkin 1 which is a member extending outward in the lateral direction Y from the absorbent body 4. The back sheet 3 and the side sheet 6 are bonded to each other at the extension from the side edges along the longitudinal direction X of the absorber 4 by a known bonding means such as an adhesive, heat seal, ultrasonic seal or the like. Each of the top sheet 2 and the back sheet 3 may be bonded to the absorber 4 by an adhesive. As the top sheet 2 and the back sheet 3, various kinds of materials conventionally used in absorbent articles such as sanitary napkins can be used without particular limitation. For example, as the surface sheet 2, nonwoven fabric of a single layer or a multilayer structure, an apertured film, etc. can be used. A moisture permeable resin film or the like can be used as the back sheet 3.

  As shown in FIG. 1, the side flaps largely project outward in the longitudinal central area B in the lateral direction Y, whereby a pair of left and right sides along the longitudinal direction X of the absorbent main body 5 are provided. 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 of the absorbent main body 5 in a plan view as shown in FIG. The wing portion adhesive portion (not shown) for fixing the wing portion 5W to the clothes such as the shorts is formed. The wing portion 5W is used by being folded back to the non-skin facing surface (outer surface) side of the crotch portion of the clothes such as shorts. The wing adhesion portion is covered with a release sheet (not shown) made of film, nonwoven fabric, paper or the like before its use. Further, on the skin opposing surface of the absorbent main body 5, that is, on both sides along the longitudinal direction X in the skin opposing surface of the surface sheet 2, a pair is provided so as to overlap the left and right sides along the longitudinal direction X of the absorber 4 in plan view. The side sheets 6, 6 are disposed over substantially the entire length of the absorbent main body 5 in the longitudinal direction X. The pair of side sheets 6 and 6 are joined to other members such as the top sheet 2 by known joining means such as an adhesive at joining lines (not shown) extending in the longitudinal direction X, respectively.

  As shown in FIG. 1 and FIG. 2, the surface sheet 2 and the absorbent core 40 are integrally recessed on the non-skin opposing surface side of the absorbent core 40 on the skin facing surface of the top sheet 2 in the absorbent main body 5. The recess 7 is partially formed. In the recess 7 in the napkin 1, the top sheet 2, the core wrap sheet 41 and the absorbent core 40 are integrally recessed toward the back sheet 3 side. The recess 7 is formed by subjecting the napkin 1 to a known pressing process such as embossing or ultrasonic embossing with or without heat from the skin-facing surface, that is, the surface sheet side. It can also be said that "pressing department". The recessed part 7 has a high density compared with the peripheral part (non-formed part of the recessed part) due to being formed by squeezing. In addition, when the recess 7 is formed by squeezing with heat, at the bottom of the recess 7, the fiber material (the fiber (the fiber constituting the surface sheet 2, the core wrap sheet 41 and the absorbent core 40) The mass 11, the hydrophilic fiber 12F) may be thermally fused and integrated.

  The recessed portion 7 is disposed to surround the central portion in the lateral direction Y at the central portion in the longitudinal direction X of the absorbent core 40. As shown in FIG. 1, the recess 7 is formed at least in the longitudinal central area B. More specifically, the concave section 7 is closer to the longitudinal central area B in the rear area C than the longitudinal central area B in the front area A. It is continuous in the longitudinal direction X over the part. The recess 7 is linear in plan view as shown in FIG. 1, and the linear recess 7 has a closed annular shape in plan. The annular recess 7 has a long shape in the longitudinal direction X in plan view, and the longitudinal direction thereof coincides with the longitudinal direction X. In each of the front area A and the rear area C, the annular concave portion 7 is formed in a U-shape or arc shape convex outward in the longitudinal direction X, and the U-shaped or arc-shaped top portion is a napkin It is located at the center of 1 in the lateral direction Y. Further, in the vertical central area B, the annular concave portion 7 is formed in a pair of left and right lines extending in the vertical direction X. Thus, the recessed portion 7 is formed so as to surround the central portion in the horizontal direction Y of the longitudinal central region B, and the excretory portion facing portion located at the central portion is surrounded by the recessed portion 7 . As an effect that can be exhibited by the formation of the concave portion 7, the diffusion of the liquid in the plane direction of the absorber 4 (the absorbent core 40), in particular, in the lateral direction Y is suppressed. The shape retention of is improved, and the like.

  When not in use, the napkin 1 is folded in the longitudinal direction X from the unfolded state as shown in FIG. 1 to form the individual package 10 shown in FIG. On the skin-facing surface of the top sheet 2, as shown in FIG. 1, a folding line 8 used when the napkin 1 is folded with the top sheet 2 inside extends in a predetermined direction. In the napkin 1, the fold lines 8 are present respectively in the front and back in the longitudinal direction X across the excretory part facing part, and a total of two fold lines 8 are present. One of the two folds 8 extends in the lateral direction Y through the base near the front area A of each of the pair of wings 5W, 5W, and the other is the rear area of each of the pair of wings 5W, 5W Extending in the lateral direction Y through the root closer to C, the two folds 8 are parallel to one another.

  In the discrete packaging body 10, a laminate of the napkin 1 and the packaging material 10W has two folds crossing the laminate in the lateral direction Y with the skin-facing surface (the surface sheet 2 side) of the napkin 1 inside. It is configured to be folded in three in the longitudinal direction X at 8, 8. In a state in which the napkin 1 is folded in three, the pair of wing portions 5W and 5W are each bent to the top sheet 2 side. The packaging material 10W has a rectangular shape in a plan view, the longitudinal direction of which is made to coincide with the longitudinal direction X of the napkin 1, and the non-skin facing surface (back sheet 3) of the napkin 1 is attached via an adhesive (not shown). It is stuck. A fastening tape 10T is disposed on the upper surface of the discrete package 10 so as to straddle the longitudinal direction end of the packaging material 10W in the longitudinal direction X. The extension portions from the side edge along the longitudinal direction X of the napkin 1 in the packaging material 10W are joined by a known joining means such as an adhesive, heat seal or the like to form a sealing portion 10S. The basic configuration of the individual package 10 is the same as the individual package of a known sanitary napkin.

  In order to open the individual packaged body 10, the fastening tape 10T is pinched with a finger to peel off the sealing portion 10S of the side edge portion, then the packaging material 10W is removed and the napkin 1 is taken out. In the surface sheet 2 of the napkin 1 taken out in this manner, as shown in FIG. 4, there is a concern that a “fold” shown by reference numeral 100 in FIG. At the formation position of the fold line 8 in the individual package 10, a strong external force by folding acts on the absorber 4 for a long time, so the absorber 4 is deformed at the formation position to form a fold. Such folds can be a cause of leakage due to a reduction in the wearing feeling of the napkin 1 and a reduction in the adhesion with the skin of the wearer.

  Reference numeral 80 in FIG. 4 is a “fold” formed along the fold line 8. The fold line 80 is a flat line-like area of a predetermined width centered on the fold line 8, and its width, that is, the extending direction of the fold line 8 (longitudinal direction of the fold line, in the napkin 1, the transverse direction Y) The length in the direction orthogonal to and is not particularly limited, but is usually about 1 to 10 mm.

  In order to solve the problem of such a fold by individual packaging, as shown in FIG. 2 in the napkin 1, the absorbent core 40, in addition to the hydrophilic fibers 12F, a fiber mass 11 of a specific shape including a synthetic fiber 11F. Was included. The absorbent core 40 is characterized in that, in addition to containing the fiber mass 11, the plurality of fiber masses 11 or the fiber mass 11 and the hydrophilic fiber 12F are entangled. Hereinafter, the absorbent core 40 will be described.

  As used herein, “fiber mass” refers to a fiber assembly in which a plurality of fibers are united. As a form of a fiber lump, the sheet piece divided | segmented from the synthetic fiber sheet which has a fixed magnitude | size, for example is mentioned. In particular, a non-woven fabric is selected as the synthetic fiber sheet, and non-woven fabric pieces cut out from the non-woven fabric into predetermined sizes and shapes are preferable as the fiber mass.

  Thus, 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 pieces, but from the sheet pieces Also, it is manufactured by cutting a large size fiber sheet (preferably non-woven fabric) (see FIG. 6). The plurality of fiber masses contained in the absorbent core according to the present invention are a plurality of sheet-shaped fiber masses having higher formability as compared with those produced by the prior art such as Patent Documents 3 and 4. .

In the absorbent core 40, a plurality of fiber masses 11 or the fiber mass 11 and the hydrophilic fibers 12F are entangled. In the absorbent core 40 of the present embodiment, a plurality of fiber masses 11 are joined with constituent fibers (fibers 11F and 12F) in the absorbent core 40 by entanglement to form one fiber mass continuum. Further, the plurality of fiber masses 11 may be entangled, and the fiber masses 11 and the hydrophilic fibers 12F may be entangled. Furthermore, usually, the plurality of hydrophilic fibers 12F are also entangled with each other. At least a portion of the plurality of fiber masses 11 contained in the absorbent core 40 is entangled with another fiber mass 11 or the hydrophilic fiber 12F. In the absorbent core 40, all of the plurality of fiber masses 11 contained therein may be entangled with each other to form one fiber mass continuum, or the plurality of fiber mass continuums are not mutually It may be mixed in the coupled state.

  Since the fiber mass 11 is excellent in flexibility and the like, containing the fiber core 11 in the absorbent core 40 potentially makes the absorbent core 40 excellent in flexibility and the like. In the absorbent core 40, in addition to the inclusion of such a fiber mass 11, the fiber masses 11 or the fiber mass 11 and the hydrophilic fiber 12F are also joined together by entanglement, so that the absorbent core 40 is further excellent in response to external force, and excellent in shape retention, flexibility, cushioning property, compression recovery, and the like. For example, the absorbent core 40 can be flexibly deformed with respect to external force (for example, the body pressure of the wearer) received from various directions when the napkin 1 is worn, and can be brought into close contact with the wearer's body with good fit.

As described above, in the absorbent core 40, where the fiber mass 11 or the fiber mass 11 and the hydrophilic fiber 12F are entangled, the “interlacing” of the fiber mass 11 or the like referred to here is the following form A and B are included.
Form A: A form in which the fiber masses 11 are joined not by fusion but by entanglement of constituent fibers 11 F of the fiber mass 11.
Form B: In the natural state of the absorbent core 40 (no external force is applied), the fiber masses 11 and the like are not coupled, but in the state where an external force is applied to the absorbent core 40, the fiber masses 11 and the like are The form which can be couple | bonded by the entanglement of constituent fibers 11F. Here, "a state in which an external force is applied to the absorbent core 40" means, for example, a state in which a deforming force is applied to the absorbent core 40 during wearing of the absorbent article to which the absorbent core 40 is applied. .

  Thus, in the absorbent core 40, as in the form A, the fiber mass 11 is bonded to the other fiber mass 11 or the hydrophilic fiber 12F by entanglement or “interlacing” of the fibers with each other, and the form Like B, it is also present in a state in which it can be entangled with another fiber mass 11 or hydrophilic fiber 12F, and the entanglement of such fibers more effectively expresses the above-mentioned effect of the absorbent core 40. It has become one of the important points. However, the absorbent core 40 preferably has the “confounding” of Form A from the viewpoint of shape retention. The entanglement of the fibers is entangled compared to the entanglement by “fusion of fibers” as described in Patent Document 3, for example, since there is no bonding component or fusion and only entanglement of the fibers. The freedom of movement of the individual elements (fiber mass 11, hydrophilic fibers 12F) is high, so that the individual elements can move within a range that can maintain the integrity as an assembly made of them. As described above, the absorbent core 40 has a plurality of fiber masses 11 contained therein, or the fiber mass 11 and the hydrophilic fibers 12F, which are relatively loosely bonded to each other. Possible shape retention is moderate, and shape retention and cushioning properties, compression recovery, etc. are compatible at a high level.

  It is not necessary for all of the bonding modes through the fiber mass 11 in the absorbent core 40 to be "entangled", and a part of the absorbent core 40 includes other bonding modes other than the confounding, such as bonding with an adhesive. It may be

  However, the remainder obtained by removing “fusion through fiber mass 11” formed in the absorbent core 40 as a result of being integrated with other members of the absorbent article, such as the above-described leak-proof groove, from the absorbent core 40 In the portion of the absorbent core 40, that is, in the absorbent core 40 itself, it is desirable that the bonding between the fiber masses 11 or the bonding between the fiber masses 11 and the hydrophilic fibers 12F be made only by “fiber interlacing”.

From the viewpoint of more reliably expressing the function and effect of the absorbent core 40 described above, the “fiber lump 11 bonded by interlacing” which is Form A and the “fiber lump 11 in a state capable of being entangled” which is Form B The total number of is preferably at least half, more preferably at least 70%, more preferably at least 80%, based on the total number of fiber masses 11 in the absorbent core 40.
From the same point of view, the number of fiber masses 11 having “entanglement” of form A is 70% or more, particularly 80% or more, of the total number of fiber masses 11 having bonding portions with other fiber masses 11 or hydrophilic fibers 12F. Is preferred.

  Two typical external shapes are shown by FIG. 5 about the preferable form of the fiber mass 11. As shown in FIG. More specifically, the fiber mass 11A shown in FIG. 5A has a rectangular parallelepiped shape, and the fiber mass 11B shown in FIG. 5B has a disk shape. The fiber mass 11A, 11B is common in that it includes two opposing base planes 111 and a body plane 112 connecting the two basic planes 111. Each of the basic surface 111 and the skeletal surface 112 is a portion which is recognized to be substantially non-uniform at a level applied when evaluating the degree of surface irregularity in an article mainly composed of this type of fiber.

The rectangular fiber-shaped fiber mass 11A of FIG. 5A has six flat surfaces, and among the six surfaces, two opposing surfaces having the largest area are the basic surfaces 111 and the remaining The four faces are skeletal faces 112 respectively. The basic surface 111 and the skeletal surface 112 intersect with each other, more specifically, are orthogonal to each other.
The disc-shaped fiber mass 11B shown in FIG. 5 (b) has two flat surfaces facing each other in a circular shape in plan view and a curved peripheral surface connecting the two flat surfaces. Each surface is a basic surface 111, and the circumferential surface is a skeletal surface 112.
The fiber masses 11A and 11B are also common in that the skeletal surface 112 has a rectangular shape, more specifically, a rectangular shape in plan view.

  The plurality of fiber masses 11 contained in the absorbent core 40 each have two opposing basic surfaces 111 and a skeletal surface 112 connecting the two basic surfaces 111, such as the fiber masses 11A and 11B shown in FIG. It differs from the non-woven fabric pieces or fine webs described in Patent Documents 3 and 4 which are indeterminate shaped fiber aggregates in that they are "formed fiber aggregates". In other words, when any one fiber mass 11 in the absorbent core 40 is seen through (for example, when observed with an electron microscope), the see-through shape of the fiber mass 11 differs depending on the observation angle, and one fiber Where there are multiple fluoroscopic shapes per mass 11, each of the plurality of fiber masses 11 in the absorbent core 40, as one of its multiple fluoroscopic shapes, connects two opposing base surfaces 111 and two base surfaces 111. And a skeletal surface 112 having a specific perspective shape. The plurality of non-woven fabric pieces or fine webs contained in the absorbent (absorbent core) described in Patent Literatures 3 and 4 are substantially "surfaces" such as the basic surface 111 and the skeletal surface 112, that is, an enlarged portion. And have different external shapes from each other and are not “fixed”.

  As described above, Patent Documents 3 and 4 show that the plurality of fiber masses 11 included in the absorbent core 40 is a “shaped fiber assembly” defined by the basic surface 111 and the skeletal surface 112. Since the uniform dispersion of the fiber mass 11 at a predetermined portion (skin facing surface side) of the absorbent core 40 is improved as compared with the case of the irregular shaped fiber assembly as described, the fiber assembly such as the fiber mass 11 By blending the body into the absorbent core 40, the expected effects (i.e., the effects of improving the cushioning property, the flexibility, the compression recovery property, etc. of the absorber) can be stably exhibited. In particular, in the case of a rectangular parallelepiped fiber mass 11 as shown in FIG. 5A, the outer surface is composed of six surfaces of two basic surfaces 111 and four skeletal surfaces 112, so that it is shown in FIG. As compared with the disk-shaped fiber mass 11 having three outer surfaces as described above, it is possible to have a relatively large opportunity for contact with the other fiber mass 11 or the hydrophilic fiber 12F, and the entanglement is enhanced, and the shape retention is improved. It can also lead to the improvement of

In the present embodiment, in the fiber mass 11, the basic surface 111 has a larger area than the skeletal surface 112. In the fiber lumps 11A and 11B shown in FIG. 5, in addition to the magnitude relation such as “area of basic surface 111> area of skeletal surface 112”, the total area of the two basic surfaces 111 is the total area of skeletal surface 112 A magnitude relationship of greater than that also holds true. That is, in the rectangular parallelepiped fiber mass 11A of FIG. 5A, the sum of the areas of the two basic surfaces 111 is larger than the sum of the areas of the four skeletal surfaces 112, and FIG. In the disk-shaped fiber mass 11B, the sum of the areas of the two basic surfaces 111 is larger than the area of the skeletal surface 112 forming the circumferential surface of the disk-shaped fiber mass 11B. In any of the fiber masses 11A and 11B, the basic surface 111 is the surface having the largest area among the plurality of surfaces possessed by the fiber masses 11A and 11B.

  Thus, the fiber mass 11 includes the two opposing basic surfaces 111 and the skeletal surface 112 connecting them, and the above-mentioned magnitude relation of “area of the primary surface 111> area of the skeletal surface 112”, and further Is satisfied by the above-mentioned “the total area of both basic surfaces 111 is larger than that of the skeletal surface 112”, the basic surface 111 having a relatively large area mainly has the liquid permeability of the fiber mass 11. The skeletal surface 112, which contributes to the improvement and has a relatively small area, mainly supports the basic surface 111 contributing to its liquid permeability strongly, and the external pressure such as the body pressure of the wearer of the napkin 1 is an absorbent core Even in the case of 40, the liquid permeability of the basic surface 111 is maintained. Therefore, the absorbent core 40 including a plurality of fiber masses 11 having such a characteristic outer shape can have high cushioning properties even after liquid absorption, is less likely to be curled, and can be excellent in liquid drawability.

  The reason why the fiber mass 11 is such a “shaped fiber aggregate” defined by the two basic surfaces 111 and the skeletal surface 112 intersecting the two basic surfaces 111 is because of the method of producing the fiber mass 11 It is. Production of the fiber mass 11 is carried out using a cutting means such as a cutter as shown in FIG. 6 as a raw material fiber sheet 10bs (a sheet having the same composition as the fiber mass 11 and having a larger size than the fiber mass 11). The plurality of fiber masses 11 produced by cutting into a fixed shape and so produced are uniform in shape and size. FIG. 6 is a view for explaining the method of manufacturing the rectangular parallelepiped fiber mass 11A of FIG. 5A, and the dotted line in FIG. 6 shows a cutting line. In the absorbent core 40, a plurality of fiber masses 11 having uniform shape and size, which are obtained by cutting the fiber sheet into a fixed shape as described above, are blended. As mentioned above, a nonwoven fabric is preferable as the raw fiber sheet 10bs.

  As shown in FIG. 6, the rectangular fiber-shaped fiber mass 11A of FIG. 5 (a) has a raw fiber sheet 10bs in a second direction intersecting (more specifically, orthogonal to) the first direction D1 and the first direction D1. It is manufactured by cutting into a predetermined length to D2. The two directions D1 and D2 are respectively predetermined one directions in the plane direction, and the sheet 10bs is cut along the thickness direction Z orthogonal to the plane direction. As described above, in a plurality of rectangular parallelepiped fiber masses 11A obtained by cutting the raw fiber sheet 10bs into so-called eyelids, the cut surfaces thereof, that is, the surfaces contacting with the cutting means such as a cutter at the time of cutting the sheet 10bs , The non-cutting surface, ie, the surface not in contact with the cutting means, is the basic surface 111. The basic surface 111 is the front and back surface (surface orthogonal to the thickness direction Z) in the sheet 10bs, and as described above, is the surface having the largest area among the plurality of surfaces of the fiber mass 11A.

  The spacing L1a (the spacing in the first direction, see FIG. 6) and the spacing L2a (the spacing in the second direction, see FIG. 6) of the cutting lines at the time of cutting the raw fiber sheet 10bs From the viewpoint of securing the necessary dimensions, etc., it is preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 30 mm or less, more preferably 15 mm or less.

  The above description of the fiber mass 11A basically applies to the disk-shaped fiber mass 11B of FIG. 5 (b). The substantial difference from the fiber mass 11A is only the cutting pattern of the raw fiber sheet 10bs, and when the sheet 10bs is cut into a fixed shape to obtain the fiber mass 11B, it is matched to the planar view shape of the fiber mass 11B The sheet 10bs may be cut into a circular shape.

  Further, the outer shape of the fiber mass 11 is not limited to that shown in FIG. 5, and both the basic surface 111 and the skeletal surface 112 are flat surfaces which are not curved as in the respective surfaces 111 and 112 of FIG. Alternatively, it may be a curved surface as in the skeletal surface 112 (the peripheral surface of the disk-shaped fiber mass 11B) in FIG. 5 (b). The basic surface 111 and the skeletal surface 112 may have the same shape and the same size, and specifically, for example, the outer shape of the fiber mass 11A may have a cubic shape.

  As described above, the two types of surfaces (basic surface 111 and skeletal surface 112) possessed by the fiber mass 11 (11A, 11B) are cut of the raw fiber sheet 10bs by cutting means such as a cutter at the time of manufacturing the fiber mass 11. And the non-cut surface (basic surface 111) which is a surface which the sheet 10bs originally has and is not in contact with the cutting means. Then, due to the difference between the cut surface and the cut surface, the skeletal surface 112, which is the cut surface, has a feature that the number per unit area of the fiber end is larger than the basic surface 111, which is the non-cut surface. Have. The term "fiber end" as used herein means the end in the lengthwise direction of the constituent fibers 11F of the fiber mass 11. Usually, fiber ends are also present in the base surface 111 which is a non-cut surface, but the skeletal surface 112 is formed by cutting the raw fiber sheet 10 bs due to being a cut surface formed by cutting. A large number of fiber ends consisting of the cut ends of the constituent fibers 11F exist in the entire skeletal surface 112, that is, the number of fiber ends per unit area is larger than that of the basic surface 111. .

  The fiber end portion present on each surface (basic surface 111, skeletal surface 112) of the fiber mass 11 is between the fiber mass 11 and another fiber mass 11 contained in the absorbent core 40 or the hydrophilic fiber 12F. Useful for forming confounds. Generally, as the number of fiber ends per unit area increases, the interlacing property is improved, which may lead to the improvement of various properties such as the shape retention property of the absorbent core 40. And, as described above, the number per unit area of the fiber end on each surface of the fiber mass 11 is not uniform, and the number per unit area of such a fiber end is “skeleton surface 112> basic surface 111”. Since the size relationship is established, the interlacing property with the other fibers (the other fiber mass 11 and the hydrophilic fiber 12F) via the fiber mass 11 differs depending on the surface of the fiber mass 11, and the skeletal surface 112 is the basic surface 111 Confoundability is higher than. That is, the bonding by interlacing with other fibers through the skeletal surface 112 has a stronger bonding force than that through the basic surface 111, and the basic surface 111 and the skeletal surface in one fiber mass 11 At 112, there may be a difference in bonding strength with other fibers. Generally, the stronger the bonding strength, the more the freedom of movement of the bonded fibers is limited, and the strength (shape retention) of the absorbent core 40 as a whole is improved, but the softness tends to be reduced. .

  Thus, in the absorbent core 40, each of the plurality of fiber masses 11 contained therein has two types of bonding strength with respect to the other fibers (the other fiber masses 11, the hydrophilic fibers 12F) in the periphery thereof. And the absorbent core 40 has both moderate softness and strength (shape retention). And when the absorptive core 40 which has such an outstanding characteristic is used according to a conventional method as an absorber of an absorptive article, the wearer of the absorptive article can be provided with a comfortable wearing feeling. In addition, the disadvantage that the absorbent core 40 is broken by external force such as the body pressure of the wearer at the time of wearing is effectively prevented.

In particular, in the fiber mass 11 (11A, 11B) shown in FIG. 5, as described above, the area of the basic surface 111 is larger than the area of the skeletal surface 112, and the total area of the two basic surfaces 111 is the skeletal surface. Where the total area of the fibers is greater than 112, this means that the number of fiber ends per unit area is relatively small, and hence the base surface 111, which is relatively less entangled with other fibers, Means that the total area is larger than the skeletal surface 112 having the opposite property. Therefore, the fiber mass 11 (11A, 11B) shown in FIG. 5 has the other fibers in the periphery (other fiber masses 11, hydrophilic fibers 12F, as compared to the fiber mass in which the fiber end uniformly exists on the entire surface. ), And even if it is entangled with other fibers around it, it is easy to entangle with relatively weak bonding power, and therefore, it is difficult to become a large dam and a cushion excellent in the absorbent core 40 Sex, flexibility, etc. can be given.

  On the other hand, since the non-woven fabric pieces or fine webs described in Patent Documents 2 and 3 are manufactured by, for example, cutting the raw fiber sheet into an irregular shape with a cutter such as a mill cutter as described above, It is not a piece of sheet-like shaped fiber lump having a "face" like the face 111 or the skeletal face 112, and furthermore, the external force of the cutting process is applied to the entire fiber lump at the time of its production. The fiber ends of the above are randomly formed in the entire fiber mass, and it is difficult to sufficiently express the above-mentioned effects by the fiber ends.

The dimensions and the like of each part of the fiber mass 11 (11A, 11B) are preferably set as follows. The dimensions of each part of the fiber mass 11 can be measured based on an electron micrograph or the like.
When the basic surface 111 is rectangular in plan view as shown in FIG. 5A, the length L1 of the short side 111a is preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 10 mm or less More preferably, it is 6 mm or less.
The length L2 of the long side 111b of the base surface 111 having a rectangular shape in plan view is preferably 0.3 mm or more, more preferably 2 mm or more, and preferably 30 mm or less, more preferably 15 mm or less.
In the case where the basic surface 111 is the surface having the largest area among the plurality of surfaces of the fiber mass 11 as shown in FIG. 5, the length L2 of the long side 111 b is the maximum passing length of the fiber mass 11. The maximum crossing length corresponds to the diameter of the base surface 111 of the disk-shaped fiber mass 11B in a plan view.
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, still more preferably, 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. 5A, but may be a square shape, that is, the ratio of lengths L1 and L2 of two sides orthogonal to each other is , L1 / L2 may be one.
The thickness T of the fiber mass 11, ie, the length T between two opposing base surfaces 111, is preferably 0.1 mm or more, more preferably 0.3 mm or more, and preferably 10 mm or less, more preferably 6 mm or less is there.

  From the viewpoint of further improving the cushioning property and the like of the absorbent core 40, it is preferable that in the absorbent core 40, a plurality of fiber masses 11 be present so as to overlap in the thickness direction. More specifically, in the projection view in the thickness direction of the absorbent core 40 (when the absorbent core 40 is observed from the skin facing surface or the non-skin facing surface), a plurality of fibers in an arbitrary 10 mm square unit area Preferably, there is an overlap of masses 11. The presence of the plurality of fiber masses 11 in the absorbent core 40 in such a manner that they overlap in the thickness direction makes it possible, in addition to the improvement of the cushioning properties of the absorbent core 40, menstrual blood etc. Due to the formation of a temporary stock space that can temporarily hold the body fluid of the present invention, the liquid absorbability of the absorbent core can be expected to be improved. From the same point of view, it is preferable that the fiber mass 11 be uniformly dispersed and present throughout the surface direction of the absorbent core 40, and it is more preferable that the fiber mass 11 be uniformly dispersed and present throughout the absorbent core 40.

The constituent fibers 11F of the fiber mass 11 include synthetic fibers. The synthetic fiber used as the fiber 11F is preferably a hydrophobic synthetic fiber. Since the constituent fiber 11F of the fiber mass 11 is a hydrophobic fiber having a low degree of hydrophilicity, not only when the absorbent core 40 is in a dry state, but also when it absorbs moisture (body fluid such as urine or menstrual blood) to be in a wet state Even in the above case, the effects (reformability such as shape retention, flexibility, cushioning property, compression recovery property, stiffness of the roll, etc.) resulting from the presence of the fiber mass 11 described above are stably exhibited. . The fibers 11F are more preferably hydrophobic and non-bibulous. The content of synthetic fibers as constituent fibers 11F in the fiber mass 11 is preferably 90% by mass or more with respect to the total mass of the fiber mass 11, and 100 mass%, that is, the fiber mass 11 is formed of only synthetic fibers Is most preferred. In particular, when the synthetic fiber as the constituent fiber 11F is non-water-absorptive, the effects due to the presence of the fiber mass 11 described above are exhibited more stably.

  Similarly, from the viewpoint of enabling the absorbent core 40 to exhibit excellent effects in shape retention, flexibility, cushioning property, compression recovery property, stiffness in the dry state and the wet state. The fiber mass 11 preferably has a three-dimensional structure in which a plurality of thermoplastic fibers are heat-sealed to one another. Further, in order to obtain a fiber mass 11 in which a plurality of heat fusion bonding portions are three-dimensionally dispersed, a synthetic fiber used as a constituent fiber 11F of the fiber mass 11 is preferably a thermoplastic fiber. In order to obtain a fiber mass 11 in which a plurality of heat fusion bonding portions are three-dimensionally dispersed, the raw material fiber sheet 10bs (see FIG. 6) may be configured in the same manner. As described above, the raw material fiber sheet 10bs in which the fusion-bonded portion is dispersed three-dimensionally can be manufactured by applying heat treatment such as hot air treatment to the web or nonwoven fabric mainly composed of thermoplastic fibers.

  As a hydrophobic and non-water absorbing synthetic resin (thermoplastic resin) suitable as a material of the constituent fiber 11F of the fiber mass 11, for example, polyolefin such as polyethylene and polypropylene; polyester such as polyethylene terephthalate; nylon 6, nylon 66 etc. And polyacrylic acid, polymethacrylic acid alkyl ester, polyvinyl chloride, polyvinylidene chloride and the like, and one of these may be used alone or in combination of two or more. The fiber 11F may be a single fiber composed 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 here is a synthetic fiber (thermoplastic fiber) obtained by combining two or more types of synthetic resins having different components with a spinneret and simultaneously spinning them, and a plurality of components are continuous in the longitudinal direction of the fiber. In a single fiber, which has the same structure. The form of the composite fiber includes a core-sheath type, a side-by-side type, and the like, and is not particularly limited.

  On the other hand, as the hydrophilic fiber 12F used in combination with the fiber mass 11, a hydrophilic fiber conventionally used as a forming material of an absorbent body of this type of absorbent article can be used. For example, softwood pulp or hardwood pulp Natural fibers such as non-wood pulp such as cotton pulp and hemp pulp; modified pulps such as cationized pulp and mercerized pulp; regenerated fibers such as cupra and rayon; semi-synthetic fibers such as acetate etc. These 1 type can be used individually or in mixture of 2 or more types. In view of the fact that the main role of the hydrophilic fiber 12F is the improvement of the liquid absorbability of the absorbent core 40, the hydrophilic fiber 12F is particularly preferably a water-absorbent fiber, and among the above-mentioned hydrophilic fibers, natural fibers, Regenerated fibers (cellulose-based fibers) are preferred, and pulp-based (cellulose-based) water-absorbing fibers are particularly preferred.

  In the absorbent core 40, the content mass ratio of the fiber mass 11 to the hydrophilic fiber 12F is not particularly limited, and may be appropriately adjusted according to the types of the constituent fiber (synthetic fiber) 11F of the fiber mass 11 and the hydrophilic fiber 12F. Just do it. For example, when the constituent fiber 11F of the fiber mass 11 is a thermoplastic fiber (hydrophobic and non-absorbent synthetic fiber) and the hydrophilic fiber 12F is a cellulose fiber (water absorbent fiber), the predetermined effect of the present invention From the viewpoint of ensuring play, the mass ratio of the fiber mass 11 to the hydrophilic fiber 12F is preferably 20/80 to 80/20 as the former (fiber mass 11) / the latter (hydrophilic fiber 12F). And more preferably 40/60 to 60/40.

The content of the fiber mass 11 in the absorbent core 40 is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 80% by mass or less, based on the total mass of the absorbent core 40. Is 60 mass% or less.
The content of hydrophilic fibers 12F in the absorbent core 40 is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 80% by mass or less, based on the total mass of the absorbent core 40. Preferably it is 60 mass% or less.

The basis weight of the fiber mass 11 in the absorbent core 40 is preferably 32 g / m ² or more, more preferably 80 g / m ² or more, and preferably 640 g / m ² or less, more preferably 480 g / m ² or less .
The basis weight of the hydrophilic fiber 12F in the absorbent core 40 is preferably 32 g / m ² or more, more preferably 80 g / m ² or more, and preferably 640 g / m ² or less, more preferably 480 g / m ² or less is there.

  The absorbent core 40 may contain other components other than the fiber mass 11 and the hydrophilic fiber 12F, and can illustrate a water absorbing polymer as another component. As a water absorbing polymer, generally, a particulate one is used, but a fibrous one may be used. When a particulate water-absorbing polymer is used, its shape may be spherical, massive, bowl-like or amorphous. The average particle size of the water-absorbing polymer is preferably 10 μm or more, more preferably 100 μm or more, and preferably 1000 μm or less, more preferably 800 μm or less. Generally, polymers or copolymers of acrylic acid or alkali metal acrylates can be used as the water-absorbing polymer. Examples include polyacrylic acid and its salts and polymethacrylic acid and its salts.

  As described above, the absorbent core 40 contains the fiber mass 11 having a specific shape including the synthetic fiber 11F and the hydrophilic fiber 12F, and the plurality of fiber masses 11 or the fiber mass 11 and the hydrophilic fiber 12F are melted. Because a relatively loosely coupled "movable area" is formed by entanglement without wearing, even if an external force such as a wearer's body pressure acts on the absorbent core 40 while the napkin 1 is worn Due to the presence of such a movable region, it is possible to exhibit softness and resistance to deflection, exhibit high fit to the wearer's skin, and also exhibit gentle shape retention by interlacing fiber materials. In the napkin 1, since the absorbent core 40 excellent in such softness, cushioning property, compression recovery property, etc. is disposed on the non-skin facing surface side of the surface sheet 2, the napkin 1 is individually dressed as shown in FIG. Even when stored in the form of the body 10 for a long time, it is difficult for the folds to be formed on the surface sheet 2 at the formation positions of the folds 8.

  In addition to the provision of the absorbent core 40 excellent in cushioning properties and the like, the napkin 1 also has a fold even when the fiber mass 11 is in a specific arrangement and in a specific state at the formation position of the fold 8. The formation of folds at the formation position of 8 is inhibited. That is, in the napkin 1, as shown in FIGS. 7 (a) and 7 (b), the absorbent core 40 is folded in a portion overlapping the fold 8 in the thickness direction (a portion overlapping the fold 8 in plan view). A fiber bundle 11S exists across the curve 8 in a direction crossing the extending direction (longitudinal direction of the curve 8), and there is a portion where the fiber masses 11 are not fused to each other. The fiber bundle crossing fiber mass 11S is the same as the other fiber mass 11 except that the fiber bundle 11S is disposed so as to straddle the bending curve 8. In the embodiment shown in FIGS. 7 (a) and 7 (b), the fold-crossing fiber mass 11S spans the folding line 8 in a direction (longitudinal direction X) orthogonal to its extending direction (horizontal direction Y). .

Even if the absorbent core 40 is excellent in cushioning properties etc., as shown in FIG. 7C, for example, when the fiber mass 11 does not exist at all in the portion overlapping the bending curve 8 in the absorbent core 40 in the thickness direction. When the fiber mass 11 having a rectangular shape in plan view is disposed with the longitudinal direction thereof aligned with the extending direction of the folding line 8 (in the illustrated form, in the lateral direction Y), or as shown in FIG. If the fiber mass 11 is relatively small (the maximum cross-over length in plan view is short) and it is difficult to take an arrangement across the folding line 8 in the direction intersecting the extending direction, the folding line in the absorbent core 40 Since the hydrophilic fiber layer poor in cushioning properties and the like consisting only of hydrophilic fibers 12F is continuous over the entire length of the folding line 8 in the portion overlapping with the layer 8 in the thickness direction, the surface sheet 2 is formed at the forming position of the folding line 8 When There is a possibility that wrinkles are formed. On the other hand, in the napkin 1, the hydrophilic fiber layer is shredded due to the presence of the fiber crosses 11 S as shown in FIGS. 7A and 7 B, and the entire length of the fold 8 is continuous. Being inhibited.

  In order to ensure that the fiber mass 11S crosses the bending line in the absorbent core 40, it is preferable that the fiber mass 11 be uniformly dispersed and present in the entire surface direction of the absorbent core 40, and the absorbent core It is further preferable that the core 40 be uniformly dispersed and present. In addition, it is also advantageous to ensure that the fiber mass 11 is relatively large (the maximum crossing length is relatively long) so that the fiber mass 11S can be reliably present in the absorbent core 40 (this point Will be described later).

  Further, even if the fiber crosses 11S are present in the portion overlapping the fold 8 in the absorbent core 40 in the thickness direction, if all the fiber bodies 11 present in this portion are fused, Since the rigidity of the portion concerned becomes high, the napkin tends to be broken so as to avoid the fused fiber mass 11, and there is a possibility that it can not straddle the bending curve 8 as shown in FIG. 7 (d). Furthermore, it is not preferable in manufacture because the folding is not stable as designed. However, in the napkin 1, there is a portion where the fiber masses 11 are not fused to each other at a portion overlapping in the thickness direction with the bending curve 8 in the absorbent core 40, such concern is wiped out.

  In the napkin 1, as shown in FIG. 1, a part of the folding line 8 and the recessed part 7 overlap in the thickness direction, and in the part overlapping the overlapping part of the absorbent core 40 in the thickness direction, the recessed part Due to the formation method of 7, the fiber masses 11 may be fused together. However, the ratio of the area of the overlapping portion with the recessed portion 7 in the entire area in a plan view of the bending line 8 is small, specifically, usually about 10% or less. That is, most of the portion of the absorbent core 40 overlapping the fold line 8 in the thickness direction (the portion other than the portion overlapping the recess 7 in the thickness direction) is entangled without fusion between the fiber masses 11.

From the viewpoint of more reliably preventing the occurrence of creases due to individual packaging, the fold-crossing fiber mass 11S is
As shown in FIGS. 7 (a) and 7 (b), not only the fold line 8 but also the fold 80 formed along the fold line 8 is straddled in the direction intersecting with the extending direction preferable. In this case, as shown in FIG. 7A, in the case of “crossing the fold in the direction crossing the extending direction”, it is only necessary to use a form in which one folding curve crossing fiber mass 11S spans the fold 80. As shown in FIG. 7 (b), a plurality of (two in the illustrated embodiment) straddle fiber clusters 11S adjacent to each other in the extension direction of the fold line 8 have a form straddling the crease 80 as a whole. Is included.

  In the embodiment shown in FIG. 7 (b), the folding curve straddle fiber mass 11S straddling only one of both side edges along the extending direction (longitudinal direction X) of the fold 80 and the folding curve straddle fiber mass straddling only the other 11S are at least partially at the same position in the thickness direction of the absorbent core 40, and are disposed in proximity to each other in the extending direction, so that apparently one folding line crossing fiber mass 11S has a fold 80 Straddle both sides of the Therefore, the effect of preventing the generation of a crease due to individualization, which is achieved by the mode shown in FIG. 7 (b), is substantially equal to that achieved by the mode shown in FIG. 7 (a). In the embodiment shown in FIG. 7 (b), the distance between the plurality of fold line crossing fiber masses 11S adjacent in the extension direction of the fold line 8 is preferably within 30 mm, from the viewpoint of reliably preventing the occurrence of folds. More preferably, it is within 10 mm.

  However, from the viewpoint of more reliably preventing the occurrence of creases due to individualization, as shown in FIG. 7A, the fold-crossing fiber mass 11S spans the fold 80 in the direction intersecting the extending direction thereof It is preferable to include one fiber mass 11S. In other words, it is preferable that the fold across fiber mass 11S include at least one having a size that can straddle the fold 80 in the direction intersecting with the extending direction.

  From the same point of view, the maximum crossing length of the basic surface 111 (the length indicated by the symbol L2 in FIG. 5) in the fold-crossing fiber mass 11S is the extension direction of the fold 80 formed along the fold line 8 It is preferable to be longer than the length in the orthogonal direction (in the illustrated embodiment, the longitudinal direction X). Moreover, such a configuration makes it possible to make the fiber mass 11S more reliably exist in the absorbent core 40.

In order to effectively prevent the occurrence of creases due to individual packaging, the number of fiber crosses 11S is required to some extent. From such a point of view, the number of fold-crossing fiber masses 11S present in an arbitrary 50 mm ³ cubic region in a portion overlapping the fold 8 in the absorbent core 40 in the thickness direction is preferably 3 or more, more preferably 5 It is more than one. The number of fiber mass 11S across the bending line is measured, for example, by the following method. That is, the absorbent core 40 is taken out from the absorbent article to be measured, for example, the napkin 1, and the length in the extension direction of the fold 8 is 50 mm from the portion overlapping the fold 8 in the thickness direction. The length 1 mm and the depth 1 mm in the direction orthogonal to the extending direction may be cut out as a measurement sample, and the measurement sample may be visually observed to count the number of fiber masses 11 contained therein.

  In the napkin 1, as shown in FIG. 1, when the folding line 8 crosses the napkin 1 in the lateral direction Y, the napkin 1 is folded outward in the longitudinal direction X of the folding line 8 (fold line 80). It has a high rigidity area 45 which is higher in bending rigidity than the curve 8 (fold 80). More specifically, in the napkin 1, a high-rigidity area 45 in the shape of a long oval in a plan view at the central portion in the horizontal direction Y of the longitudinal central area B, which is the area sandwiched between the two folds 8 and 8. Are arranged with their major axis directions aligned with the longitudinal direction X. In addition, the center in the horizontal direction Y of the rear area C, specifically, the rear side of the rear area C with respect to the fold line 8 extending in the horizontal direction Y through the base near the rear area C of each of the pair of wing portions 5W. In the part, another highly rigid area 45 having a long oval shape in a plan view is disposed with the major axis direction thereof aligned with the longitudinal direction X.

  As described above, in the napkin 1 in the direction orthogonal to the extending direction of the fold line 8 (fold line 80), it is closer to the fold line 8 (fold line 80) and more rigid than the fold line 8 (fold line 80) The high-rigidity region 45 is disposed so that when the napkin 1 is folded to form the individual package 10, the napkin 1 is bent preferentially at the folding line 8. That is, the high rigidity region 45 functions as a bending guide portion that causes the napkin 1 to be bent at the folding line 8 as designed.

  In the high rigidity region 45 of the napkin 1, as shown in FIG. 1, a plurality of high rigidity portions 46 are intermittently arranged. The high rigidity portion 46 is typically formed by performing known squeezing processing such as heat embossing, ultrasonic embossing, etc. at a planned formation position of the high rigidity region 45 in the absorbent core 40. In the high rigidity portion 46, the fiber masses 11 present in the high rigidity portion 46 are fused to form a fused portion. Moreover, the high rigidity part 46 formed by such pressing process is high-density compared with the other part (non-pressing part) of the absorptive core 40 to which the pressing process is not given. The pressing process for forming the high rigidity portion 46 may be performed from the skin facing surface side of the absorbent core 40 or may be performed from the non-skin facing surface side.

  As the high rigidity area 45 in which the high rigidity part 46 which is a pressing part of the fiber mass 11 is present, the flexibility of the absorbent core 40 and the certainty of the folding position, ie, the folding line 8 is assured at a predetermined position. From the viewpoint of achieving coexistence with the above, it is preferable that the plurality of high rigidity parts 46 (squeezed parts) be intermittently arranged as shown in FIG. In the high rigidity area 45 shown in FIG. 1, the plurality of high rigidity parts 46 (squeezed parts) are surrounded by the low rigidity part (non-squeezed part) having a rigidity lower than that. Compared with the case where the entire area of the high rigidity portion 46 is, flexibility, cushioning property, and the like are high.

  In the embodiment shown in FIG. 1, the plurality of circular high rigidity parts (squeezed parts) 46 in a plan view are arranged in a zigzag manner, but the pattern (shape and arrangement in plan view) of the high rigidity parts 46 is not limited thereto. . For example, as a plan view shape of the high rigidity portion 46, in addition to a circular shape as shown in the drawing, an elliptical shape, a quadrangular shape to a rhombus shape, a polygonal shape of pentagon or more, etc. may be mentioned.

As mentioned above, although this invention was demonstrated based on the embodiment, this invention can be suitably changed, without being restrict | limited to the said embodiment.
For example, in the said embodiment, although the absorber 4 was comprised including the absorptive core 40 and the core wrap sheet 41 which coat | covers this, the core wrap sheet 41 may not be.
Further, in the absorbent core according to the present invention, all of the fiber mass (synthetic fiber aggregate) contained in the absorbent core may not be a shaped fiber aggregate such as the fiber mass 11, and it deviates from the spirit of the present invention As long as it is not within the range, a very small amount of irregular fiber assembly may be contained in addition to such a fixed fiber assembly.
The absorbent article of the present invention widely includes articles used for absorbing body fluid (urine, soft feces, menstrual blood, sweat, etc.) discharged from the human body, and in addition to the above-described sanitary napkins, sanitary shorts and fastenings The so-called unfolded disposable diaper having a tape, the pants-type disposable diaper, the incontinence pad and the like are included.

1 Sanitary napkin (absorbent article)
A Front area B Vertical center area C Back area 2 Top sheet 3 Back sheet 4 Absorbent body 40 Absorbent core 11 Fiber mass 11S Fold curve cross fiber mass 11F Constituent fibers of fiber mass (synthetic fibers)
DESCRIPTION OF SYMBOLS 110 Body part 111 Basic surface 112 Skeletal surface 12F Hydrophilic fiber 41 Core wrap sheet 45 High rigidity area 46 High rigidity part 5 Absorbent main body 7 Concave part 8 Folded curve 80 Fold 10bs Raw material fiber sheet of fiber lump 10 Individual packaging

Claims (7)

An absorbent comprising: an absorbent body including an absorbent core; and a surface sheet disposed on the skin-facing side of the absorbent body, and having a longitudinal direction corresponding to the front-rear direction of the wearer and a lateral direction orthogonal thereto. An article,
The absorbent core contains a fiber mass containing a synthetic fiber and a hydrophilic fiber, and the fiber mass or the fiber mass and the hydrophilic fiber are entangled,
The fiber mass comprises two opposing base surfaces and a skeletal surface connecting the two base surfaces,
A fold line used when folding the absorbent article with the surface sheet inside is extended in a predetermined direction on the skin facing surface of the surface sheet,
In a portion of the absorbent core overlapping in the thickness direction with the fold line, a cross section crossing the fold line in a direction crossing the extension direction is present, and the fiber masses are not fused An absorbent article in which a part exists.   The fold line according to claim 1, wherein the fold line transversely crosses the absorbent article, and has a high rigidity region having a bending stiffness higher than that of the fold line in the longitudinal direction of the fold line. Absorbent article.   The absorbent article according to claim 2, wherein a high rigidity portion is present in the high rigidity region.   The absorbent article according to claim 2 or 3, wherein a plurality of high rigidity portions are intermittently arranged in the high rigidity region.   The absorbent article according to any one of claims 1 to 4, wherein the folding line is present before and after each of longitudinal sections across the excretory part opposing part disposed opposite to the excretory part of the wearer.   The maximum crossing length of the basic surface in the fold over fiber mass is longer than the length in the direction orthogonal to the extension direction of the fold formed along the fold line. An absorbent article according to any one of the preceding claims. The fold-over fiber mass according to any one of claims 1 to 6, wherein the fiber mass includes one fiber mass straddling a fold formed along the fold line in a direction intersecting with the extending direction thereof. Absorbent article.

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