TW201929802A - Absorbent and absorbent article - Google Patents

Abstract

This absorbent (4) comprises: fiber masses (11) containing synthetic fibers (11F); and water-absorbent fibers (12F). The plurality of fiber masses (11) are entangled with one another, or the fiber masses (11) and the water-absorbent fibers (12F) are entangled with one another. The fiber masses (11) have a main body (110) defined by two principal surfaces (111) which face one another, and skeleton surfaces (112) which intersect with the principal surfaces (111). The synthetic fibers (11F) contain a hydrophilic agent. In addition, the absorbent article (1) of this invention is equipped with the absorbent (4) of this invention.

Description

Absorbent body and absorbent article

The present invention relates to an absorbent body for an absorbent article.

An absorbent article such as a disposable diaper or a menstrual sanitary napkin is generally configured to be disposed at a position relatively close to the wearer's skin and disposed at a position relatively far from the wearer's skin. The back sheet and the absorber interposed between the two sheets. In many cases, the absorbent body is composed of a hydrophilic fiber (water-absorbent fiber) such as wood pulp and further contains water-absorbing polymer particles. In the absorbent body used for the absorbent article, the improvement of various properties such as flexibility (buffering property), compression recovery property, and shape retention property is large.

For example, Patent Document 1 discloses that a hydrophobic fiber having a fiber length longer than that of a pulp fiber, for example, is not hydrophilized in an absorbent body mainly composed of a pulp fiber or a water-absorbent polymer. Synthetic fibers such as polypropylene are dispersed in the pulp fibers. It is considered that according to Patent Document 1, the absorbent body does not have a back-infiltration phenomenon of the body fluid due to the presence of the hydrophobic fiber, and the strength is improved by entanglement of the hydrophobic fiber having a long fiber length and the pulp fiber. Maintain conformity.

Further, in Patent Document 2, it is described that a hydrophilic long fiber having a fiber length longer than that of a pulp fiber, such as enamel, cotton, wool, hemp, etc., is dispersed in an absorbent body mainly composed of a pulp fiber and a water-absorbing polymer. In the pulp fiber. According to Patent Document 2, the absorbent body can stably maintain its shape before and after the body fluid is absorbed, and since the absorbent body is obtained by dispersing the hydrophilic long fibers without heat treatment, the absorbent body is preferably maintained as a whole. The texture is less obstructive to the absorption of body fluids.

Further, Patent Document 3 discloses an absorbent body comprising a nonwoven fabric sheet and a hydrophilic fiber, which comprises a heat-fusible fiber and is bonded to each other in advance to give a three-dimensional structure. The non-woven fabric of the three-dimensional structure is produced by pulverizing the nonwoven fabric into a fine sheet by a pulverization method such as a chopper method, and the above-described manufacturing method causes an unfixed shape as described in FIGS. 1 and 3 of the document. There is essentially no part that can be considered as a plane. Patent Document 3 describes a preferred embodiment of the absorbent body described in the literature in which the nonwoven fabric sheets are thermally fused. In the absorbent body described in Patent Document 3, since the nonwoven fabric sheet has a three-dimensional structure, voids are formed inside the absorbent body, and the recovery property when moisture is absorbed is improved, and as a result, the water absorption performance is improved.

Further, Patent Document 4 describes a fine fiber web including a relatively dense microfiber core and fibers or fiber bundles extending outward from the core, and it is described that the fine fiber web and the wood can be used. A nonwoven web in which pulp or water-absorbing polymer particles are mixed is used as an absorbent for an absorbent article. In the same manner as the non-woven fabric described in Patent Document 3, the microfiber web is formed by forming a non-fixed shape in the same manner as the non-woven fabric described in Patent Document 3, and does not substantially have a portion which can be regarded as a flat surface. Prior Technical Literature Patent Literature

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Bulletin

The present invention relates to an absorbent body comprising a fiber block containing synthetic fibers and water-absorbent fibers, and a plurality of the fiber blocks are entangled with each other or the fiber block and the water-absorbing fibers are intertwined with each other. The fiber block has a body portion formed by dividing two fundamental faces and a skeleton face that intersects the two basic faces. The above synthetic fiber contains a hydrophilizing agent. Further, the present invention relates to an absorbent article comprising the above absorbent body of the present invention.

In addition to the cellulose-based fibers such as pulp fibers, the absorbents described in Patent Documents 1 and 2 contain synthetic fibers or hydrophilic long fibers such as hydrazine, and therefore have higher rigidity than those containing only cellulose fibers as constituent fibers. Therefore, various characteristics such as cushioning property and compression recovery property can be expected to be improved. However, the plurality of synthetic fibers contained therein are independently present, and are not formed as one of the aggregated members. Therefore, the improvement effects of these various characteristics are not sufficient. Therefore, when it is applied to an absorbent article, it is easy to wrinkle and the conformability becomes insufficient, and particularly, after absorbing urine or a body fluid such as menstrual blood, the occurrence of such a problem is remarkable.

On the other hand, in the absorbent body described in Patent Documents 3 and 4, since the synthetic fiber contained in the absorbent fiber is a synthetic fiber aggregate called a nonwoven fabric sheet or a fine fiber web, improvement in cushioning properties and the like can be expected. However, as described above, the synthetic fiber assembly contained in the absorbent body described in Patent Documents 3 and 4 is produced by pulverizing a nonwoven fabric mainly composed of synthetic fibers into a fine sheet shape, or pulling it off or pulling it off. Therefore, the shape is not fixed and the shape and size are not uniform. Therefore, when mixed with pulp fibers or the like, it is difficult to obtain uniform mixing of the two and the desired effect cannot be obtained. In addition, as in the preferred embodiment of the absorbent body described in Patent Document 3, when all of the synthetic fiber aggregates contained in the absorbent body are thermally fused to each other, the movement of the synthetic fibers itself is restricted, and as a result, the hardness of the entire absorbent body is increased. Various properties such as softness are reduced.

Therefore, the present invention relates to an absorbent article and an absorbent article using the same, which are excellent in cushioning property and compression recovery property, and are excellent in external force responsiveness and can be flexibly deformed, thereby being applied to an absorbent article. In a situation, the wearing feeling can be improved.

Hereinafter, a preferred embodiment of the absorbent article of the present invention and the absorbent article of the present invention having the same will be described with reference to the drawings. Fig. 1 and Fig. 2 show a menstrual napkin 1 as an embodiment of the absorbent article of the present invention. The sanitary napkin 1 is provided with an absorbent body 4 that absorbs and retains body fluid, a liquid-permeable front sheet 2 that is disposed on the opposite side of the skin of the absorbent body 4 and that is in contact with the skin of the wearer, and a front sheet 2 that is disposed in the absorbent body 4. The backsheet 3 which is liquid-impermeable to the non-skin facing side. As shown in Fig. 1, the sanitary napkin 1 has a longitudinal direction X extending from the ventral side of the wearer to the back side via the crotch portion, and a transverse direction Y orthogonal to the longitudinal direction X, in the longitudinal direction of the wearer, and X is divided into a longitudinal central region B including an opposing portion (excretion point) of the excretory portion opposite to the excretory portion such as the genitals other than the wearer, and is disposed on the ventral side of the wearer facing the excretory portion (the opposite side of the excretory portion) The front side) is a front area A, and a total of three areas arranged in the rear side (back side) rear side area C of the wearer's opposite side.

In the present specification, the "skin facing surface" is an absorbent article or a constituent member thereof (for example, the absorbent body 4) which faces the skin side of the wearer when worn by the absorbent article, that is, the skin of the wearer. On the near side, the "non-skin opposing surface" is the side of the absorbent article or its constituent member that is worn toward the absorbent article and faces the side opposite to the skin side, that is, the side farther from the wearer's skin. . Here, "when wearing" refers to a state in which a normal wearing position, that is, a proper wearing position of the absorbent article, is maintained.

As shown in Fig. 1, the sanitary napkin 1 has an absorbent body 5 having a shape elongated in the longitudinal direction X, and a longitudinal central portion B of the self-absorbent body 5 along the longitudinal direction X, respectively, in the lateral direction Y. One pair of wings 5W, 5W is extended on the outside. The absorbent body 5 is a part of the main body of the sanitary napkin 1, and includes the front sheet 2, the back sheet 3, and the absorber 4, and is divided into a front area A, a vertical center area B, and a rear area C in the longitudinal direction X. 3 areas.

Further, in the case where the absorbent article of the present invention has a wing portion such as a sanitary napkin, the absorbent article has a longitudinal direction (longitudinal direction, X direction in the drawing) of the absorbent article. In the region of the wing portion, if the sanitary napkin 1 is exemplified, it is sandwiched between the root portion of one wing portion 5W along the root portion of the longitudinal direction X and the root portion of the other wing portion 5W along the longitudinal direction X. Further, the longitudinal center region in the absorbent article having no wing portion means a region in the middle where the absorbent article is equally divided in the longitudinal direction.

In the sanitary napkin 1, the absorbent body 4 is composed of a liquid-absorbent absorbent core 40 and a liquid-permeable core sheet 41 covering the outer surface of the absorbent core 40. Similarly to the absorbent body 5, the absorbent core 40 has a shape elongated in the longitudinal direction X in plan view as shown in Fig. 1, and the longitudinal direction of the absorbent core 40 coincides with the longitudinal direction X of the sanitary napkin 1, and is absorbed. The width direction of the core 40 coincides with the lateral direction Y of the sanitary napkin 1. The absorbent core 40 and the core sheet 41 may be joined by an adhesive such as a hot-melt adhesive. Further, the absorber 4 may not include the packaged core material 41. In this case, the absorbent core 40 is directly used as the absorbent body 4 for the absorbent article.

In this way, the absorbent body 4 which is one embodiment of the absorbent body of the present invention is indirectly in contact with the skin of a person by being incorporated in an absorbent article such as the sanitary napkin 1, that is, indirectly by a member such as the front sheet 2; The skin is applied to the user, and has a non-skin contrast surface on the opposite side of the skin and the opposite side thereof, and has a longitudinal direction X corresponding to the front and rear directions of the wearer of the sanitary napkin 1 and a transverse direction Y orthogonal to the longitudinal direction X, and In the longitudinal direction X, it is divided into three areas of the front area A, the vertical center area B, and the rear area C. Further, the absorbent body 4 can be used in direct contact with the human skin in addition to such contact.

In the sanitary napkin 1, the packaged core material 41 is a continuous sheet having a width of twice or more and three times or less the length of the lateral direction Y of the absorbent core 40, as shown in Fig. 2, covering the absorbent core 40 across the entire area of the skin facing surface, and extending from the side edges of the absorbent core 40 along the longitudinal direction X to the outside of the lateral direction Y, the extension is rolled down below the absorbent core 40, The entire area of the non-skin opposing surface of the absorbent core 40 is covered. Furthermore, in the present invention, the packaged chip material may not be such a sheet, and may be configured, for example, to cover a skin-side package chip of the skin opposite to the absorbent core 40. A total of two sheets of non-skin side-packaged sheets of the non-skin opposing surface of the absorbent core 40 are coated separately from the skin-side pack core material.

As shown in Fig. 2, the front sheet 2 covers the entire area of the skin facing surface of the absorbent body 4. On the other hand, the back sheet 3 covers the entire area of the non-skin opposing surface of the absorbent body 4, and further extends from the both sides of the longitudinal direction X of the absorbent body 4 toward the outer side of the lateral direction Y, and the side sheets described below. The materials 6 together form a side flap. The side flap portion is a portion of the sanitary napkin 1 that includes a member that extends from the absorbent body 4 to the outer side of the lateral direction Y. The back sheet 3 and the side sheet 6 are joined to each other at the extending portions of the side edges of the self-absorbent body 4 along the longitudinal direction X by a known joining means such as an adhesive, heat sealing, or ultrasonic sealing. Each of the front sheet 2 and the back sheet 3 may be joined to the absorber 4 by an adhesive. As the front sheet 2 and the back sheet 3, various sheets previously used for absorbent articles such as menstrual napkins can be used without particular limitation. For example, as the front sheet 2, a nonwoven fabric of a single layer or a multilayer structure, an apertured film, or the like can be used. As the back surface sheet 3, a moisture permeable resin film or the like can be used.

As shown in Fig. 1, the side flap portions are largely protruded outward in the lateral direction Y in the longitudinal center region B, whereby a pair of wing portions 5W and 5W are provided on the left and right sides of the absorbent body 5 along the longitudinal direction X. In the plan view shown in FIG. 1, the wing portion 5W has a lower trapezoidal shape (the side longer than the upper base) and has a substantially trapezoidal shape on the side of the side of the absorbent body 5, and the wing is formed on the non-skin opposing surface. The portion 5W is fixed to a wing portion adhering portion (not shown) of clothes such as shorts. The wing portion 5W is used for folding back to the non-skin opposing surface (outer surface) side of the crotch portion of the garment such as a pair of shorts. The wing adhesive portion is covered with a release sheet (not shown) including a film, a nonwoven fabric, or paper before use. Further, the pair of side sheets 6 and 6 are formed on both sides of the longitudinal direction X of the skin facing surface of the absorbent sheet 5, that is, the skin facing surface of the absorbent body 5, and the absorbent body 4 in plan view. The left and right sides of the longitudinal direction X are arranged so as to overlap substantially the entire length of the longitudinal direction X of the absorbent body 5. Each of the pair of side sheets 6 and 6 is joined to another member such as the front sheet 2 by a known joining means such as an adhesive, in a joint line (not shown) extending in the longitudinal direction X.

One of the main features of the sanitary napkin 1 is an absorbent core 4, particularly an absorbent core 40 which forms a main body of the absorbent body 4. In Figure 3, a portion of the absorbent core 40 is shown. As shown in FIGS. 2 and 3, the absorbent body 4, more specifically, the absorbent core 40 includes a fiber block 11 containing a plurality of fibers (synthetic fibers) 11F, and a water absorbent fiber 12F. The fiber block 11 is a fiber assembly in which the fibers 11F are intentionally aggregated and integrated, and the water-absorbent fibers 12F are not intentionally integrated, and are present in an absorbable state in a state in which they can exist independently. In the core 40. The fiber block 11 mainly contributes to an improvement in 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 an improvement in liquid absorbability, shape retention, and the like of the absorbent core 40. Further, the absorbent core 40 may be substantially referred to as the absorbent body 4 itself. Hereinafter, the description of the absorbent core 40 will be appropriately applied to the absorbent body 4 unless otherwise specified. That is, in the present invention, the case where the absorber does not include the packaged core material and is formed only of the absorbent core, in this case, the absorber has the same meaning as the absorbent core system.

In the present specification, the "fiber block" is a fiber aggregate in which a plurality of fibers are aggregated together. Examples of the form of the fiber block include a sheet piece obtained by dividing a synthetic fiber sheet having a predetermined size. In particular, it is preferable to select a non-woven fabric as a synthetic fiber sheet, and to cut a nonwoven fabric sheet having a specific size and shape from the nonwoven fabric as a fiber block.

In this manner, the sheet-like fibrous block which is one embodiment of the preferred embodiment of the fiber block of the present invention is not configured to aggregate a plurality of fibers to form the sheet, but is larger in size than the sheet. A cut fabric manufacturer of a fiber sheet (preferably a non-woven fabric) (see Fig. 6). The plurality of fiber blocks contained in the absorbent body (absorbent core) of the present invention are a plurality of sheet-like fiber pieces which are more deformed by the manufacturer of the prior art as disclosed in Patent Documents 3 and 4.

It is preferable that 90% by mass or more of the constituent fibers 11F of the fiber block 11 are synthetic fibers, more preferably 100% by mass, that is, all of the constituent fibers 11F are synthetic fibers. Further, as described below, it is more preferable that the constituent fibers 11F which are synthetic fibers are non-absorbent.

In the absorbent core 40, a plurality of fiber blocks 11 are entangled with each other, or the fiber block 11 is entangled with the water-absorbing fibers 12F. In the absorbent core 40 of the present embodiment, a plurality of fiber blocks 11 are bonded to each other by the constituent fibers (fibers 11F and 12F) in the absorbent core 40 to form one fiber block continuous body. Further, a plurality of fiber blocks 11 may be entangled with each other, and the fiber block 11 may be entangled with the water absorbing fibers 12F to be bonded. Further, usually, a plurality of water absorbent fibers 12F are also entangled with each other. At least a part of the plurality of fiber blocks 11 contained in the absorbent core 40 is interlaced with the other fiber block 11 or the water absorbent fibers 12F. In the absorbent core 40, there may be a case where a plurality of the fiber blocks 11 contained therein are entangled with each other to form one fiber block continuum, or there may be a plurality of fiber block continuums mixed with each other in a non-bonded state. situation.

Since the fiber block 11 is excellent in flexibility and the like, it is contained in an absorbent body (absorbent core), and the absorbent body is potentially excellent in flexibility and the like. In the absorbent core 40, since the fiber block 11 is contained, and the fiber blocks 11 or the fiber block 11 and the water-absorbing fiber 12F are also joined to each other by entanglement, the external force of the absorbent core 40 is It is more excellent in responsiveness, and is excellent in shape retention, flexibility, cushioning properties, compression recovery, and the like. For example, when the absorbent core 40 is worn by the sanitary napkin 1, it can be flexibly deformed by external force (for example, the body pressure of the wearer) from various directions, and the conformability is well adhered to the wearer's body.

In FIG. 4, the deformed state in which the absorbent core 40 is compressed by the external force F is schematically shown. In the absorbent core 40 in which the fiber block 11 as the fiber assembly and the water-absorbent fiber 12F as the non-fiber assembly are mixed, the rigidity of the two members 11, 12F is poor, and the boundary between the two members 11, 12F is BL. (dashed line in FIG. 4) is particularly easy to flex, and the boundary BL functions as a flexure portion when the absorbent core 40 is deformed, and the boundary BL as the flexure portion generally exists throughout the entire area of the absorbent core 40. Therefore, the absorbent core 40 is responsive to various external forces and is flexibly deformed, and when the external force is released, the compression recovery property of the fiber block 11 can be quickly restored to the original state. The deformation-recovery characteristic of the absorbent core 40 is exhibited not only in the case where the absorbent core 40 is compressed, but also in the case of twisting. In other words, the absorbent core 40 loaded in the sanitary napkin 1 is placed between the two leg portions of the wearer when the sanitary napkin 1 is worn, so that the absorbent core 40 is moved by the wearer. When the two thighs move and twist around the imaginary axis of rotation extending in the longitudinal direction X, in this case, the absorbent core 40 has a higher deformation-recovery characteristic, and thus Since the force is easily deformed and recovered from the twist of the two large legs, it is not easy to wrinkle, and the sanitary napkin 1 can be given a higher conformity with respect to the wearer's body.

As described above, in the absorbent core 40, the fiber blocks 11 are entangled with each other or the fiber block 11 and the water-absorbing fibers 12F are entangled. Here, the "interlacing" of the fiber blocks 11 and the like includes the following forms A and B. . Form A: The form in which the fiber blocks 11 and the like are not joined by fusion but by the entanglement of the constituent fibers 11F of the fiber block 11 with each other. Morphology B: The fiber blocks 11 are not bonded to each other in the natural state of the absorbent core 40 (the state in which no external force is applied), but the fiber blocks 11 and the like can be used in a state where an external force is applied to the absorbent core 40. The form in which the constituent fibers 11F are entangled with each other and joined. Here, the "state in which an external force is applied to the absorbent core 40" is, 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.

As a result, in the absorbent core 40, as in the form A, the fiber block 11 and the other fiber block 11 or the water-absorbent fiber 12F are joined by the mutual entanglement of the fibers, that is, as in the form B, It is also present in a state of being entangled with the other fiber block 11 or the water-absorbent fiber 12F, and the combination by the entanglement of the fibers is one of the important aspects for more effectively exhibiting the effect of the above-described absorbent core 40. However, in terms of conformality, the absorbent core 40 preferably has the "interlacing" of Form A. Since the bonding by the entanglement of the fibers is not formed by the use of the subsequent components or the fusion, and the fibers are formed by being entangled with each other, for example, the fusion of fibers is described as described in Patent Document 3. In combination, the elements of the entanglement (the fiber block 11 and the water absorbing fiber 12F) have a higher degree of freedom of movement, and therefore, the respective elements can be moved within a range capable of maintaining the physical properties of the aggregate including the same. In this way, the absorbent core 40 is relatively loosely bonded to each other by the plurality of fiber blocks 11 or the fiber block 11 and the water-absorbing fibers 12F, and has a loose shape retaining property when deformed by an external force. At a higher level, both shape retention, cushioning and compression recovery are considered.

The combination of the fibrous cores 11 in the absorbent core 40 is entirely "interlaced", and a portion of the absorbent core 40 may be bonded to other portions of the absorbent core 40, such as by an adhesive. Wait.

However, the remaining portion of the absorbent core 40 that is formed by the fusion of the absorbent core 40 and the "absorptive portion of the absorbent core 40" is removed from the absorbent core 40, that is, the absorbent portion is absorbed. The core 40 itself, preferably the fiber block 11 is bonded to each other, or the combination of the fiber block 11 and the water-absorbing fiber 12F is formed only by "cohesion of fibers".

From the viewpoint of further enhancing the effect of the above-described absorbent core 40, the fiber block 11 joined by the entanglement as the form A and the fiber block 11 in the state of the entangled state as the form B The total count is preferably more than half of the total number of the fiber blocks 11 in the absorbent core 40, more preferably 70% or more, and still more preferably 80% or more. From the same point of view, the number of the fiber blocks 11 having the "coincidence" of the form A is preferably 70% or more of the total number of the fiber blocks 11 having the joint portion with the other fiber block 11 or the water absorbent fibers 12F. More than 80%.

One of the main features of the absorbent core 40 is an outer shape of the fiber block 11. In Fig. 5, a typical outer shape of the two kinds of fiber blocks 11 is shown. The fiber block 11A shown in Fig. 5(a) is formed into a rectangular column shape, more specifically, a rectangular parallelepiped shape, and the fiber block 11B shown in Fig. 5(b) is formed into a disk shape. The fiber blocks 11A and 11B are common to the two base faces 111 and the body plane 112 connecting the two base faces 111. Both the base surface 111 and the skeleton surface 112 were confirmed to have substantially no unevenness at the level of application when evaluating the degree of unevenness of the surface of the article mainly composed of such fibers.

The fiber block 11A having a rectangular parallelepiped shape in Fig. 5(a) has six flat faces, and the two faces having the largest area among the six faces are respectively the base faces 111, and the remaining four faces are the skeleton faces 112, respectively. The base surface 111 and the skeleton surface 112 intersect each other, more specifically orthogonally. The disk-shaped fiber block 11B of FIG. 5(b) has two flat faces that face each other in a circular shape in plan view, and a curved peripheral surface that connects the two flat faces, and the two flat faces are the basic faces 111, respectively. The circumference is the skeleton surface 112. The fiber blocks 11A and 11B are also common to the skeleton surface 112 in a quadrangular shape, more specifically, a rectangular shape in plan view.

The difference between the plurality of fiber blocks 11 included in the absorbent core 40 and the non-woven fabrics or microfiber webs described in Patent Documents 3 and 4 which are fiber assemblies of an unfixed shape is that the plurality of fiber blocks 11 are respectively The fiber blocks 11A and 11B shown in Fig. 5 have a "fixed-shaped fiber assembly" having two opposing base faces 111 and a skeleton face 112 connecting the two base faces 111. In other words, in the case of seeing any one of the fiber blocks 11 in the absorbent core 40 (for example, by observation with an electron microscope), the see-through shape of the fiber block 11 differs depending on the angle of observation thereof, and each of the fiber blocks 11 There are a plurality of perspective shapes, and the plurality of fiber blocks 11 in the absorbent core 40 respectively have a plurality of perspective shapes including two opposing base faces 111 and a skeleton shape 112 connecting the two base faces 111 as a plurality of perspective shapes thereof. one. The plurality of nonwoven fabric sheets or fine fiber webs contained in the absorbent body described in Patent Documents 3 and 4 do not substantially have a "face" such as the base surface 111 or the skeleton surface 112, that is, there are expanded portions, and the outer shape is different from each other, and is not "Fixed shape."

When the plurality of fiber blocks 11 included in the absorbent core 40 are a "fixed-shaped fiber assembly" formed by the basic surface 111 and the skeleton surface 112, it is compared with those described in Patent Documents 3 and 4. In the case of a fiber assembly of a non-fixed shape, the uniform dispersibility of the fiber block 11 in the absorbent core 40 is improved, so that the desired effect is achieved by blending the fiber assembly such as the fiber block 11 with the absorbent core 40. (The effect of improving the softness, cushioning property, compression recovery property, and the like of the absorbent core) is stably exhibited. Further, in particular, in the case of the rectangular block-shaped fiber block 11 as shown in Fig. 5 (a), since the outer surface includes a total of six faces of the two basic faces 111 and the four skeleton faces 112, it is compared with The fiber block 11 having the three outer surfaces and having the disk shape shown in Fig. 5(b) has a relatively large chance of contact with the other fiber block 11 or the water absorbing fiber 12F, and the entanglement property is improved, and the band may be brought. To improve the shape retention.

In the fiber block 11, the total area of the two base faces 111 is preferably larger than the total area of the skeleton faces 112. That is, in the fiber block 11A of the rectangular parallelepiped shape shown in Fig. 5(a), the sum of the areas of the two basic faces 111 is larger than the sum of the areas of the four skeleton faces 112, and is also shown in Fig. 5(b). In the disk-shaped fiber block 11B, the total area of each of the two basic faces 111 is larger than the area of the skeleton face 112 of the peripheral surface of the fiber block 11B forming the disk shape. In any of the fiber blocks 11A and 11B, the fundamental surface 111 is the surface having the largest area among the plurality of faces of the fiber blocks 11A and 11B.

The fiber block 11 which is a "fixed-shaped fiber assembly" formed by the two basic faces 111 and the skeleton faces 112 intersecting the two basic faces 111 can be realized by making the manufacturing method different from the prior art. As shown in Fig. 6, the preferred method of producing the fiber block 11 is to cut into a raw material fiber sheet 10bs (a sheet having the same composition as the fiber block 11 and having a size larger than that of the fiber block 11) using a cutting device such as a cutter. Broken to a fixed shape. The plurality of fiber blocks 11 formed in this manner are more uniformly fixed in shape and size than those of the prior art manufacturers as disclosed in Patent Documents 3 and 4. Fig. 6 is a view for explaining a method of manufacturing the fiber block 11A having a rectangular parallelepiped shape in Fig. 5(a), and a broken line in Fig. 6 indicates a cutting line. In the absorbent core 40, a plurality of fiber blocks 11 having a uniform shape and size obtained by cutting the fiber sheet into a fixed shape in this manner are prepared. As described above, the raw material fiber sheet 10bs is preferably a non-woven fabric.

The fiber block 11A having a rectangular parallelepiped shape in Fig. 5(a) is obtained by crossing the raw material fiber sheet 10bs in the first direction D1 and the first direction D1 (more specifically, orthogonal) as shown in Fig. 6 . It is manufactured by cutting in a 2 direction D2 by a specific length. The two directions D1 and D2 are respectively a specific one direction in the surface direction of the sheet 10bs, and the sheet 10bs is cut along the thickness direction Z orthogonal to the plane direction. In the fiber block 11A in which a plurality of rectangular parallelepiped shapes are obtained by cutting the raw material fiber sheet 10bs into a so-called small four-square shape in this manner, the cut surface of the sheet material 10bs is usually cut off by a cutter or the like. The surface in contact with the device is the skeleton surface 112, and the non-cut surface, that is, the surface not in contact with the cutting device, is the base surface 111. The base surface 111 is a front surface (a surface orthogonal to the thickness direction Z) of the sheet material 10bs, and as described above, the fiber block 11A has a surface having the largest area among the plurality of surfaces.

Furthermore, the above description of the fiber block 11A also substantially conforms to the disk-shaped fiber block 11B of Fig. 5(b). The substantial difference from the fiber block 11A is only the cut pattern of the raw material fiber sheet 10bs. When the sheet 10bs is cut into a fixed shape to obtain the fiber block 11B, the sheet 10bs is formed according to the plan shape of the fiber block 11B. Cut into a round shape.

Further, the outer shape of the fiber block 11 is not limited to that shown in FIG. 5, and any of the basic surface 111 and the skeleton surface 112 may be a flat surface that is not curved as in the respective faces 111 and 112 of FIG. 5(a), or Further, as shown in FIG. 5(b), the skeleton surface 112 (the circumferential surface of the disk-shaped fiber block 11B) may be a curved surface. Further, the basic surface 111 and the skeleton surface 112 may have the same shape and the same size, and specifically, for example, the shape of the fiber block 11A may be a cubic shape.

As described above, the two types of surfaces (the basic surface 111 and the skeleton surface 112) of the fiber block 11 (11A, 11B) are classified into the raw material fiber sheets by cutting the device by a cutter or the like when the fiber block 11 is manufactured. The cut surface (skeletal surface 112) formed at 10 bs and the non-cut surface (base surface 111) which is originally provided on the sheet 10bs and which is not in contact with the cutting device. Further, depending on whether or not the cut surface is different, the skeleton surface 112 as the cut surface has a feature that the number of the fiber end portions per unit area of the base surface 111 which is the non-cut surface is larger. Here, the "fiber end portion" means the longitudinal end portion of the constituent fiber 11F of the fiber block 11. Usually, the fiber end portion is also present on the basic surface 111 which is the non-cut surface. However, since the skeleton surface 112 is a cut surface formed by cutting the raw fiber sheet 10bs, it is formed by the cutting. The fiber ends constituting the cut ends of the fibers 11F are mostly present on the entire skeleton surface 112, that is, the number of the fiber ends of the skeleton faces 112 per unit area is larger than the unit area of the fiber ends of the base faces 111. Quantity.

The fiber ends present on the respective faces (the base face 111, the skeleton face 112) of the fiber block 11 are useful for forming an entanglement between the fiber block 11 and other fiber blocks 11 or water-absorbent fibers 12F contained in the absorbent core 40. . Further, in general, the larger the number of the fiber end portions per unit area, the more the entanglement property can be improved, so that various characteristics such as the shape retention property of the absorbent core 40 can be improved. Further, as described above, the number of per-unit areas of the fiber ends in the respective faces of the fiber block 11 is not uniform, and since the number of the unit area per the fiber end portion, the "skeletal surface 112> the basic surface 111" Since the relationship between the size and the size of the fiber block 11 and the other fibers (the other fiber block 11 and the water-absorptive fiber 12F) is different depending on the surface of the fiber block 11, the symmetry of the skeleton surface 112 is higher than that of the basic surface 111. That is, the bonding achieved by the entanglement with the other fibers via the skeleton face 112 is stronger than the bonding by the entanglement with the other fibers via the base face 111, and is stronger in one fiber block 11, The bond between the base surface 111 and the skeleton surface 112 may be inferior to the bonding force with other fibers.

In this way, in the absorbent core 40, the plurality of fiber blocks 11 included in the absorbent core 40 have two kinds of bonding forces with respect to the other fibers (the other fiber blocks 11 and the water absorbent fibers 12F) at the periphery thereof, thereby being entangled. The absorbent core 40 is a combination of moderate flexibility and strength (shape retention). Moreover, when such an absorbent core 40 having excellent characteristics is conventionally used as an absorbent body of an absorbent article, the wearer of the absorbent article can be provided with a comfortable wearing feeling and effectively prevented from being worn. At the time, the external force such as the body pressure of the wearer destroys the problem of the absorbent core 40.

In particular, the fiber block 11 (11A, 11B) shown in Fig. 5 has a total area of the two base faces 111 larger than the total area of the skeleton faces 112 as described above. Therefore, the number of per unit areas of the fiber ends is relatively small, so that the base surface 111 which is relatively low in complication with other fibers has a larger total area than the skeleton surface 112 having the opposite property. Therefore, the fiber block 11 (11A, 11B) shown in Fig. 5 is easily entangled with other fibers (other fiber block 11, water-absorbing fiber 12F) in the periphery as compared with the fiber block in which the fiber end portion is uniformly present on the entire surface. It is suppressed, and even if it is in contact with other fibers in the periphery, it is easy to entangle with a relatively weak bonding force. Therefore, it is difficult to form a large block, and excellent flexibility can be imparted to the absorbent core 40.

On the other hand, the nonwoven fabric sheet or the fine fiber web described in Patent Documents 3 and 4 is manufactured by cutting a raw material fiber sheet into an unfixed shape or the like as described above, and thus does not have For example, the base sheet 111 or the "face" of the skeleton surface 112 has a fixed shape of a sheet-like fiber block, and since the cutting force is applied to the entire fiber block at the time of manufacture, the fiber ends of the fibers are not formed. It is regularly formed on the entire fiber block, and it is difficult to sufficiently exhibit the above-described effects achieved by the fiber end portion.

The number N ₁ per unit area of the fiber end portion of the base surface 111 (non-cut surface) and the skeleton surface 112 (cut surface) from the viewpoint of more effectively exerting the effect achieved by the fiber end portion ) quantity per unit area of the fiber end portion N ratio of ₂ to N ₁ <N ₂ as a prerequisite to N ₁ / N ₂ good care is 0 or more, and further preferably 0.05 or more, and preferably 0.90 or less Further, it is 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 less. The number N ₁ per unit area of the fiber end portion of the base surface 111 is preferably 0 pieces/mm ² or more, more preferably 3 pieces/mm ² or more, and further preferably 8 pieces/mm ² or less, and further Good is 6 / mm ² or less. The number N ₂ per unit area of the fiber end portion of the skeleton surface 112 is preferably 5 pieces/mm ² or more, more preferably 8 pieces/mm ² or more, and further preferably 50 pieces/mm ² or less, and further Good is 40 / mm ² or less. The number of per unit areas of the fiber ends of the base surface 111 and the skeleton surface 112 was measured by the following method.

<Method for Measuring the Number of Units Per Unit Area of Fiber Ends in Each Side of the Fiber Block> Paper-coated double-sided tape (NICETACK NW-made by Miqibang Co., Ltd.) was used for the fiber-containing member (fiber block) to be measured. 15) Attach the measuring piece to the sample stage. Then, the measurement piece was subjected to platinum coating. For the coating, an ion sputtering apparatus model E-1030 (trade name) manufactured by Hitachi Naruto Co., Ltd. was used, and the sputtering time was set to 120 seconds. The JC-6000 type electron microscope manufactured by JEOL (manufactured) was used to observe the fundamental surface and the skeleton surface at a magnification of 100 times. In the observation screen of 100 times the magnification, a rectangular region having a length of 1.2 mm and a width of 0.6 mm is set at an arbitrary position of the measurement target surface (base surface or skeleton surface), and the area of the rectangular region accounts for the area of the observation screen. The observation angle or the like is adjusted in a manner of 90% or more, and then the number of the fiber end portions included in the rectangular region is measured. However, in the observation screen at a magnification of 100 times, when the measurement target surface of the fiber block is smaller than 1.2 mm × 0.6 mm, and the ratio of the area of the rectangular area to the entire observation screen is less than 90%, the observation magnification is set to be larger than After that, the number of the fiber end portions included in the rectangular region in the measurement target surface was measured in the same manner as described above. Here, in the longitudinal direction end portion of the constituent fibers of the "fiber end portion" fiber block to be measured, the portion of the constituent fiber other than the end portion in the longitudinal direction (the intermediate portion in the longitudinal direction) is measured from the measurement target surface. Excessively, the intermediate portion in the longitudinal direction is not the object of measurement. Then, the number of the fiber end portions per unit area in the measurement target surface (base surface or skeleton surface) of the fiber block was calculated by the following formula. For each of the ten fiber blocks, the number of the fiber end portions per unit area in each of the basic surface and the skeleton surface is measured in accordance with the above procedure, and the average of the plurality of measured values is set in the measurement target surface. The number of units per unit area of the fiber ends. The number per unit area (number/mm ² ) of the fiber end portion in the measurement target surface (base surface or skeleton surface) of the fiber block = the 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 block 11 has a rectangular shape in plan view as shown in Fig. 5(a), the uniform dispersibility of the fiber block 11 in the absorbent core 40 is improved. Preferably, the short side 111a of the rectangle is shorter than the thickness of the absorbent core 40 containing the fiber block 11 (11A). The ratio of the length of the short side 111a to the thickness of the absorbent core 40 is preferably 0.03 or more, more preferably 0.08 or more, still more preferably 1 or less, still more preferably 0.5 or less. The thickness of the absorbent core 40 is preferably 1 mm or more, more preferably 2 mm or more, and is preferably 10 mm or less, and more preferably 6 mm or less. The thickness of the absorbent core 40 was measured by the following method.

<Measurement method of thickness of absorbent body (absorbent core)> The object to be measured (absorbent body, absorbent core) was placed at a horizontal position without wrinkles or bending, and 5 cN/cm was measured. The thickness of the object to be measured under load of ² . Specifically, for the measurement of the thickness, for example, a thickness gauge PEACOCK DIAL UPRIGHT GAUGES R5-C (manufactured by OZAKI MFG. C0. LTD.) is used. At this time, a flat circular or square-shaped flat plate (thickness) having a size adjusted to be 5 cN/cm ² is placed between the end portion of the thickness gauge and the object to be measured. The acrylic resin plate of about 5 mm was measured and the thickness was measured. In the thickness measurement system, the average value of the measurement was calculated at 10 o'clock, and the thickness of the measurement object was determined.

The size and the like of each portion of the fiber block 11 (11A, 11B) are preferably set as follows. The size of each portion of the fiber block 11 can be measured based on an electron micrograph or the like at the time of a specific operation of the shape of the fiber block 11 described below. When the basic surface 111 is a rectangular shape as shown in FIG. 5( a ), the length L1 of the short side 111 a is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. Further, it is preferably 10 mm or less, further preferably 6 mm or less, and particularly preferably 5 mm or less. The length L2 of the long side 111b of the substantially rectangular base surface 111 is preferably 0.3 mm or more, more preferably 1 mm or more, still more preferably 2 mm or more, and further preferably 30 mm or less, and further preferably 15 Below mm, it is preferably less than 10 mm. Further, in the case where the basic surface 111 is the surface having the largest area among the plurality of faces of the fiber block 11 as shown in FIG. 5, the length L2 of the long side 111b coincides with the maximum diameter length of the fiber block 11, The maximum diameter length coincides with the diameter of the base face 111 of the circular shape in plan view of the disk-shaped fiber block 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 further preferably 1 or less, and further preferably 0.5 or less. Furthermore, in the present invention, the plan view shape of the basic surface 111 is not limited to the rectangular shape as shown in FIG. 5(a), and may be a square shape, that is, a ratio of lengths L1 and L2 of two sides orthogonal to each other. It can also be 1 in terms of L1/L2. The thickness T of the fiber block 11, that is, the length T between the two opposing basic faces 111 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and further preferably 10 mm or less, and further preferably 6 mm. the following.

Further, the absorbent core 40 is preferable because the fiber block 11 is highly densely distributed and uniformly distributed over the entire absorbent core 40, and the responsiveness of the external force is easily isotropic. From this point of view, it is preferable that in the projection view of the two directions orthogonal to each other of the absorptive core 40, the overlapping portion of the plurality of fiber blocks 11 exists in a unit area of any 10 mm square. Reference numeral 11Z in Figs. 3 and 4 denotes an overlapping portion of a plurality of fiber blocks 11. The "projection view of the two directions orthogonal to each other" is typically a projection view of the thickness direction of the absorbent core (that is, the opposite surface of the skin of the self-absorbent core or the non-skin contrast) A view of the surface of the absorbent core and a direction orthogonal to the thickness direction (ie, the case where the absorbent core is viewed from the side of the absorbent core).

In Fig. 7(a), an electron micrograph of an example of the fiber block of the present invention is shown, and Fig. 7(b) shows a view schematically showing the fiber block 11 in combination with its electron micrograph. The plurality of fiber blocks 11 included in the absorbent core 40 may include a main body portion 110 and an extended fiber portion 113 as shown in FIG. 7, and the extended fiber portion 113 is included from the main body portion 110. The fiber 11F is formed on the outer side and has a lower fiber density (the number of fibers per unit area is smaller) than the body portion 110. Further, the absorbent core 40 may include a fiber block 11 having no extended fiber portion 113, that is, a fiber block 11 including only the body portion 110. The extended fiber portion 113 may include one of the fiber ends existing on each of the faces (the base face 111 and the skeleton face 112) of the fiber block 11, which is the outer side of the fiber block 11 from the outer side of the fiber block 11 Extend the fiber ends.

The main body portion 110 is a portion formed by dividing the two opposing basic faces 111 and the skeleton faces 112 connecting the two basic faces 111. The main body portion 110 forms a main body of the fiber block 11 to form a portion having a shape other than the fixed shape of the fiber block 11, and the fiber block 11 has a relatively high degree of flexibility, cushioning property, compression recovery property and the like. It depends on the body portion 110. On the other hand, the extended fiber portion 113 mainly contributes to the mutual entanglement of the plurality of fiber blocks 11 contained in the absorbent core 40 or the improvement of the interlinkage property between the fiber block 11 and the water absorbent fiber 12F, directly with the absorbent core. The shape retention of the body 40 is related to the improvement of the conformality of the body 40, and also affects the uniform dispersibility of the fiber block 11 in the absorbent core 40, thereby indirectly enhancing the effect achieved by the body portion 110.

The body portion 110 has a higher fiber density than the extended fiber portion 113, that is, the number of fibers per unit area is larger. Further, generally, the fiber density of the body portion 110 itself is relatively uniform. The ratio of the main body portion 110 to the total mass of the fiber block 11 is usually at least 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 85% by mass or more. The main body portion 110 and the extended fiber portion 113 can be distinguished by a specific operation of the following outer shape.

The operation of the outer shape of the body portion 110 of the fiber block 11 included in the absorbent core 40 can be determined by focusing on the difference in fiber density of the fiber block 11 and its peripheral portion (the number of fibers per unit area) Or, the type of the fiber, the difference in the fiber diameter, and the like, and the "junction" between the main body portion 110 and the other portions is confirmed. The bulk density of the body portion 110 is higher than that of the extended fiber portion 113 present around it, and in general, the synthetic fiber constituting the fiber of the body portion 110 and the water absorbing fiber 12F (typically cellulose fiber) are in essence Since the size of the absorbent core 40 in which the plurality of fiber blocks 11 and the water-absorbent fibers 12F are mixed is different, the above-described boundary can be easily confirmed by focusing on the above aspects. In this way, the boundary between the basic surface 111 and the skeleton surface 112 is confirmed, and the basic surface 111 and the skeleton surface 112 are specified by the boundary confirmation operation, and the main body portion 110 is specified. This boundary confirmation operation can be performed by observing the object (absorbent core 40) at a plurality of observation angles using an electron microscope as needed. In particular, when the fiber block 11 included in the absorbent core 40 is a case where the total area of the two basic faces 111 is larger than the total area of the skeleton faces 112 of the fiber blocks 11A and 11B as shown in FIG. 5, In particular, when the base surface 111 is the surface having the largest area of the fiber block 11, the base surface 111 of the larger area can be specified relatively easily, so that the outer shape of the body portion 110 can be smoothly performed. Specific assignments.

As shown in FIG. 7, the extended fiber portion 113 includes constituent fibers 11F of the body portion 110 which are extended from at least one of the base surface 111 and the skeleton surface 112 which form the outer surface of the main body portion 110. 7 is a view of the fiber block 11 viewed from the side of the base surface 111 (the surface having the largest area among the plurality of faces of the fiber block 11), and the plurality of fibers 11F are extended from the skeleton face 112 crossing the basic face 111. The extended fiber portion 113 is formed.

The form in which the fiber portion 113 is extended is not particularly limited. In the case where the expanded fiber portion 113 includes one fiber 11F, the plurality of fibers 11F may be included as the fiber bundle portion 113S. Further, the extended fiber portion 113 includes the longitudinal end portion of the fiber 11F extending from the main body portion 110, but may include, in addition to the fiber end portion, the fiber 11F except for both ends in the longitudinal direction. The portion (the intermediate portion in the longitudinal direction) or the portion including the fiber end portion except the both end portions in the longitudinal direction (the intermediate portion in the longitudinal direction) is included instead of the fiber end portion. In other words, in the fiber block 11, both end portions of the longitudinal direction of the constituent fibers 11F are present in the main body portion 110, and the other portion, that is, the intermediate portion in the longitudinal direction, extends annularly outward from the main body portion 110 (protruding). In this case, in this case, the extended fiber portion 113 is formed by including an annular projection of the fiber 11F. In other words, one of the end portions of the fiber portion 113 which is exposed to the fiber portion 113 is exposed.

As described above, one of the main tasks of extending the fiber portion 113 is to interconnect the plurality of fiber blocks 11 contained in the absorbent core 40 with each other, or to entangle the fiber block 11 with the water-absorbing fibers 12F. In general, if the length of the extended fiber portion 113 from the main body portion 110 becomes long, or the thickness of the extended fiber portion 113 becomes thick, or the number of the fiber portion 113 which the one fiber block 11 has is extended When the amount is increased, the objects which are entangled by the extended fiber portion 113 are mutually connected and the entanglement is not easily released, so that the specific effects of the present invention are further stably exhibited.

When the fiber block 11 is obtained by cutting the raw fiber sheet 10bs into a fixed shape as shown in Fig. 6, the extended fiber portion 113 is relatively present in the skeleton surface 112 as the cut surface thereof. On the other hand, the basic surface 111 which is the non-cut surface is not present at all, or even if it exists in the basic surface 111, the number is smaller than the number of the skeleton surface 112. The reason why the fiber portion 113 is unevenly distributed in the skeleton surface 112 as the cut surface is that the extended fiber portion 113 is mostly "fluff" which is generated by the cutting of the raw fiber sheet. In other words, the skeleton surface 112 formed by the cutting of the raw material fiber sheet 10bs is entirely rubbed by the cutting device such as a cutter at the time of cutting, so that it is easy to form the pile fibers 11F including the sheet 10bs. fluff. On the other hand, since the base surface 111 which is a non-cut surface does not have friction with such a cutting device, it is not easy to form a pile, that is, the fiber part 113 is extended.

The distance L1a of the cutting line at the time of cutting the raw material fiber sheet 10bs from the viewpoint of promoting the formation of the above-mentioned extended fiber portion 113 and the size required for securing the specific effect of the fiber block 11 The interval between the one direction and the interval L2a (the interval between the second directions) is preferably 0.3 mm or more, more preferably 0.5 mm or more, and further preferably 30 mm or less, and further preferably 15 mm or less.

As shown in FIG. 7, the fiber block 11 has one of the extended fiber bundle portions 113S including the plurality of fibers 11F extending from the body portion 110, more specifically, the skeleton surface 112 to the outer side, as one of the extended fiber portions 113. At least one of the extended fiber portions 113 of the fiber block 11 may be the extended fiber bundle portion 113S. The fiber bundle portion 113S is formed by collecting a plurality of fibers 11F extending from the skeleton surface 112, and is characterized in that the length from the body portion 110 (the skeleton surface 112) is longer than that of the extended fiber portion 113. aspect. The extended fiber bundle portion 113S may also exist on the base surface 111, but typically exists on the skeleton surface 112 as shown in FIG. 7, and does not exist at the base surface 111 at all, or even if it exists in the base surface 111 The number of skeleton faces 112 present is small. The reason for this is the same as the reason why the extended fiber portion 113 mainly exists in the skeleton surface 112 as the cut surface, and has been described above.

By the fiber block 11 having such a long and relatively thick fiber bundle portion 113S which is also referred to as a large elongated fiber portion 113, the fiber blocks 11 are entangled with each other or the fiber block 11 and the water-absorbent fiber 12F are in contact with each other. Further, as a result, the specific effect of the present invention due to the presence of the fiber block 11 is further stably exhibited. The extended fiber bundle portion 113S is easily formed by performing cutting (see FIG. 6) of the raw material fiber sheet 10bs under the above-described easy raising condition.

The length of the extension of the fiber bundle portion 113S from the main body portion 110, that is, the length from the skeleton surface 112 (cut surface) is preferably 0.2 mm or more, more preferably 0.5 mm or more, and more preferably 7 mm or less, and further preferably 4 mm or less. The extension length of the extended fiber bundle portion 113S can be measured in a specific operation (intersection confirmation operation) of the shape of the outer shape of the fiber block 11. Specifically, for example, a 3M (manufactured) double-sided tape is attached to the surface of a transparent sample stage made of acrylic resin by a microscope manufactured by KEYENCE (50 magnification), and the fiber block 11 is placed. After being fixed thereto, the shape of the outer portion of the fiber block 11 is specified according to the specific operation of the outer shape, and thereafter, the length of the extended portion of the fiber 11F extending from the outer shape is measured, and the measured portion is measured. The length of the extended portion is set to extend beyond the length of the fiber bundle portion 113S.

The extended fiber bundle portion 113S is preferably such that the plurality of constituent fibers 11F are thermally fused to each other. The thermal fusion portion of the extended fiber bundle portion 113S is generally smaller than the other portion of the extended fiber bundle portion 113S (non-thermal fusion portion), and has a diameter length orthogonal to the longitudinal direction of the extended fiber bundle portion 113S. (The diameter is larger when the cross section of the heat fusion portion is circular). By extending the fiber bundle portion 113S having such a heat fusion portion which can also be referred to as a large diameter portion, the strength of the fiber bundle portion 113S itself is increased, whereby the fiber blocks 11 which are entangled via the fiber bundle portion 113S are mutually connected. The entanglement or the intersection of the fiber block 11 and the water-absorbing fiber 12F is further enhanced. Further, when the extended fiber bundle portion 113S has a heat fusion portion, the extended fiber bundle portion 113S has a case where it is not only in a dry state, but also when the moisture absorption becomes a wet state, the extended fiber bundle portion 113S itself The strength, shape retention and the like are also improved. Moreover, by virtue of this advantage, when the absorbent core 40 is applied to the sanitary napkin 1, the absorbent core 40 is self-evident when in a dry state, and absorbs urine or menstrual blood excreted by the wearer. When the body fluid is in a wet state, the effect of the presence of the fiber block 11 can be stably exhibited. The extended fiber bundle portion 113S having the heat fusion portion can be used in the manufacturing step of the fiber block 11 as shown in FIG. 6, that is, in the cutting step of the raw material fiber sheet 10bs of the fiber block 11, by using the above-mentioned "having The fiber sheet constituting the heat fusion portion of the fibers is produced as the raw fiber sheet 10bs.

As described above, the fiber block 11 is characterized in that it has a body portion 110 (a fiber assembly of a fixed shape) formed by the basic surface 111 and the skeleton surface 112, and is also characterized in that the constituent fiber 11F contains a hydrophilizing agent. The aspect of synthetic fiber. In the present invention, the "hydrophilizing agent" is one which increases the hydrophilicity of the fiber when the hydrophilizing agent is applied to the fiber, and more specifically, the agent which reduces the contact angle with water as measured by the following method. .

The fiber may be judged to be hydrophilic or hydrophobic based on the contact angle with water measured by the following method, and if the contact angle with water is less than 90 degrees, it is hydrophilic, and if it is 90 degrees or more, it is hydrophobic. Sex. The smaller the contact angle with water as measured by the following method, the higher the hydrophilicity (the lower the water repellency), and the larger the contact angle, the lower the hydrophilicity (the higher the water repellency).

<Method for Measuring Contact Angle> The fiber was taken out from the object to be measured (absorbent core), and the contact angle of water with respect to the fiber was measured. An automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. was used as the measuring device. Deionized water was used for the measurement of the contact angle. The amount of liquid ejected from the inkjet method water droplet discharge unit (pulse ejector CTC-25 having a discharge portion aperture of 25 μm manufactured by Cluster Technology Co., Ltd.) was set to 20 μL, and water droplets were dropped directly above the fibers. The drop is recorded on a high speed video device connected to a horizontally placed camera. In view of the subsequent image analysis, the video recording apparatus is preferably a personal computer loaded with a high speed capturing device. In this measurement, images were recorded every 17 msec. In the video obtained by the video, the software FAMAS is used (the software version is set to 2.6.2, the analysis method is set to the drop method, the analysis method is set to the θ/2 method, and the image processing algorithm is set to no reflection. The image processing mode is set to the frame, the threshold is set to 200, and the curvature correction is not performed. The image of the first image of the water droplets attached to the fiber is analyzed, and the surface of the water contact with the water is calculated. The angle formed is set to the contact angle. The fiber taken out from the object to be measured was cut to have a fiber length of 1 mm, and the fiber was placed on the sample stage of the contact angle meter and maintained at a level. The contact angles of the two different sites were measured for each fiber. When the contact angle of N=5 is measured to 1 after the decimal point, the value obtained by averaging the measured values of the total of 10 parts (rounded to the 2nd place after the decimal point) is defined as the contact angle of the fiber with water. . The measurement environment was set to room temperature 22±2° C. and humidity 65±2% RH.

In addition, 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 for evaluation and measurement, the absorber is fixed by an adhesive, fusion, or the like. At the time of the other constituent members, the reinforcing portion is removed by a method such as cold air blowing a cold spray within a range that does not affect the contact angle of the fibers, and thereafter the absorbent body is taken out. This sequence is common to all assays in this specification.

The case where the synthetic fiber constituting the fiber 11F of the fiber block 11 contains a hydrophilizing agent means that the fiber block 11 is hydrophilized. One of the effects obtained by hydrophilizing the fiber block 11 contained in the absorbent core 40 is an improvement in physical properties when the absorbent core 40 absorbs and holds the liquid in a wet state. According to the findings of the present invention, if the degree of hydrophilization of the constituent fibers (synthetic fibers) of the fiber block is increased (reducing the contact angle with water), the compression work amount of the absorbent core containing the absorbent core is wet (w) -WC) The tendency to increase. The increase in the value of w-WC leads to an increase in the cushioning property of the absorbent core in a wet state. Therefore, it can be said that the constituent fibers (synthetic fibers) of the fiber block contain a hydrophilizing agent and the wet state of the absorbent core. The improvement in cushioning has an effect.

Further, in the absorbent core 40, as described above, the fiber block 11 and the water-absorbent fiber 12F as the constituent members are bonded to each other by the entanglement between the same types and between the different types, and therefore, compared with the borrowing When it is bonded by fusion, the mobility of the body fluid (liquid diffusibility in the surface direction and liquid permeability in the thickness direction) is potentially increased, and if the fiber block 11 is hydrophilized, the movement of the body fluid is performed. The relevant superior features can be further improved. For example, when the absorbent core 40 initially receives the body fluid of the wearer of the sanitary napkin 1 in the intermediate portion of the skin-facing surface at the central portion of the longitudinal central region B, the body fluid can be used by The constituent fibers 11F of the hydrophilized fiber block 11 , that is, the synthetic fibers containing the hydrophilizing agent and the water-absorbent fibers 12F entangled therewith, are quickly introduced into the interior of the absorbent core 40 from the opposite portion of the excretion portion, and further The absorbent core 40 is rapidly diffused in the surface direction, and is rapidly transmitted in the thickness direction toward the non-skin opposing surface side (the back sheet 3 side).

Further, as described above, the fiber block 11 has the main body portion 110 which is formed by the basic surface 111 and the skeleton surface 112. Generally, a plurality of interfiber spaces constituting the fibers 11F are present on the surfaces 111 and 112. If the fiber block 11 having a plurality of interfiber spaces on the surface is hydrophilized, the body fluid existing outside the fiber block 11 (the body portion 110) can be introduced into the fiber by capillary action of the interfiber space. As a result of the inside of the block 11, the liquid absorbing property of the absorbent core 40 can be improved.

Further, as described above, the fiber block 11 has the extended fiber portion 113 extending outward from the body portion 110, and the extended fiber portion 113 may have an extended fiber including the plurality of fibers 11F extending from the body portion 110. In the bundle portion 113S, as long as the fiber 11F contains a hydrophilizing agent, the fiber bundle portion 113S naturally contains a hydrophilizing agent, thereby increasing the hydrophilicity, so that the movement of the body fluid through the fiber bundle portion 113S is more smoothly performed. In other words, the constituent fibers 11F of the fiber block 11 contain a hydrophilizing agent, and in addition to the effect of improving the entanglement strength of the fiber blocks 11 or the entanglement strength of the fiber block 11 and the water absorbing fibers 12F, an absorbent core can be expected. The effect of improving the mobility of the body fluid in 40 allows the body fluid to be rapidly transferred into the absorbent core 40 even when an external force is applied to the body pressure of the wearer applying the sanitary napkin 1 to the absorbent core 40.

The fiber 11F containing a hydrophilizing agent is preferably a hydrophilic fiber, and the fiber 11F, from the viewpoint of the above-described effects of the synthetic fiber containing the constituent fiber 11F of the fiber block 11 as a hydrophilizing agent. The contact angle of (synthetic fiber) with water is preferably 75 degrees or less, more preferably 70 degrees or less, still more preferably 60 degrees or less, and particularly preferably 50 degrees or less. The contact angle of the fiber 11F with water can be adjusted by appropriately adjusting the kind or content of the hydrophilizing agent contained in the fiber 11F.

The constituent fiber 11F of the fiber block 11, that is, the synthetic fiber containing the hydrophilizing agent, is produced by causing the raw material fiber to contain a hydrophilizing agent, and the contact angle of the fiber 11F prepared in this manner with water is lower than that of the raw material fiber and water. Contact angle. The form of the hydrophilizing agent in the fiber 11F is not particularly limited. Typically, the surface layer portion of the fiber 11F is in the form of a hydrophilizing agent, that is, a form in which the hydrophilizing agent adheres to the film on the surface of the raw material fiber, but for example, Instead of the above-described form, a form of a hydrophilizing agent may be added to the inside of the raw material fiber, or a hydrophilizing agent may be mixed into the raw material fiber to form a hydrophilizing agent on the surface of the raw material fiber.

The hydrophilizing agent used in the present invention is not particularly limited as long as it is a general hydrophilizing agent used for sanitary products. The hydrophilizing agent may, for example, be an anionic surfactant, a cationic surfactant, an amphoteric surfactant or a nonionic surfactant. These may be used alone or in combination of two or more. Among these, a hydrophilizing agent containing one or more selected from the group consisting of an anionic surfactant and a nonionic surfactant is preferred because it is easy to control the degree of hydrophilization. The amount of the hydrophilizing agent to be added to the synthetic fiber constituting the fiber block 11 is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably 0.05% by mass or more, based on the interface of the hydrophilizing agent. It is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 2% by mass or less.

The anionic surfactant may, for example, be an alkyl sulfate, an alkyl sulfonate, an alkyl carboxylate or an alkyl sulfosuccinate, and more preferably an anionic interface having a sulfonic acid group as a hydrophilic group. Agent.

Examples of the anionic surfactant in which the hydrophilic group is a sulfonic acid or a salt thereof include a dialkylsulfonic acid or a salt thereof, as a preferred example of exhibiting a low concentration and high permeability. Specific examples of the dialkylsulfonic acid include di-octadecylsulfosuccinic acid, dimercaptosulfosuccinic acid, ditridecylsulfosuccinic acid, and di(2-ethylhexyl). a compound obtained by esterifying a dicarboxylic acid such as sulfosuccinic acid with a dialkyl sulfosuccinic acid or a dialkyl sulfosuccinic acid to sulfonate the α-position of the diester; or 2-sulfotetraindole Acid 1-ethyl ester (or decylamine) sodium salt, or 2-sulfohexadecanoic acid 1-ethyl ester (or decylamine) sodium salt, etc., the alpha position of a saturated fatty acid or an unsaturated fatty acid ester (or guanamine) a sulfonated α-sulfo fatty acid alkyl ester (or decylamine); or a dialkyl olefin sulfonic acid obtained by sulfonating an internal olefin of a hydrocarbon chain or an internal olefin of an unsaturated fatty acid. The carbon number of each of the alkyl groups of the two chains of the dialkyl sulfonic acid is 4 or more and 14 or less, and more preferably 6 or more and 10 or less. Examples of the dialkyl sulfosuccinate include Pelex OT-P (product name) manufactured by Kao Corporation.

Examples of the above cationic surfactant include an alkyl (or alkenyl) trimethylammonium halide, a dialkyl (or alkenyl) dimethyl ammonium halide, and an alkyl (or alkenyl) pyridinium. For the halide or the like, these compounds are preferably those having an alkyl group or an alkenyl group having 6 or more and 18 or less carbon atoms. Examples of the halogen in the halogen compound include chlorine, bromine, and the like.

Examples of the amphoteric surfactant include an alkyl group (carbon number: 1 to 30) dimethyl betaine, and an alkyl group (carbon number: 1 to 30) decylamino group (carbon number: 1 to 4) dimethyl group. Betaine-type amphoteric surfactants such as betaine, alkyl (carbon number 1 to 30) dihydroxyalkyl (carbon number 1 to 30) betaine, sulfobetaine type amphoteric surfactant; or alanine type [alkane] Base (carbon number: 1 to 30) aminopropionic acid type, alkyl group (carbon number: 1 to 30) imidodipropionic acid type] amphoteric surfactant, glycine type such as alkylbetaine [alkyl (carbon) An amino acid type amphoteric surfactant such as an amphoteric surfactant or an amino acid sulfonic acid type amphoteric surfactant such as an amphoteric surfactant or an alkyl group (toluene 1 to 30) or a taurine type.

Examples of the nonionic surfactant include polyglycerol fatty acid esters such as glycerin fatty acid esters, poly (preferably n = 2 to 10) glycerin fatty acid esters, and sorbitan fatty acid esters. Preferably, the carbon number of the fatty acid is 8 to 60), the alkylene oxide adduct of the above polyol fatty acid ester (preferably, the molar number of the addition is 2 to 60 moles), and the polyoxyalkylene group (addition) Molar number 2 to 60) alkyl group (carbon number 8 to 22) decylamine, polyoxyalkylene alkyl group (addition molar number 2 to 60) alkyl group (carbon number 8 to 22) ether, polyoxyalkylene alkyl group Modified anthrone, amine-modified anthrone, and the like.

As the raw material fiber of the constituent fiber 11F of the fiber block 11, that is, the synthetic fiber not containing the hydrophilizing agent, various synthetic fibers for sanitary use can be used without particular limitation, and thermoplastic fibers are preferable. The reason why the thermoplastic fiber is preferably used as the fiber 11F is that the fiber block 11 is provided with a three-dimensional structure in which a plurality of thermoplastic fibers 11F are thermally fused to each other, and the absorbent core 40 can be protected in any of a dry state and a wet state. Excellent effects such as formability, flexibility, cushioning properties, compression recovery, and wrinkle resistance are exhibited. Further, as described above, the extended fiber bundle portion 113S preferably has a heat fusion portion, and the constituent fibers 11F of the fiber block 11 are thermoplastic fibers, and a preferred form of the extended fiber bundle portion 113S can be obtained. In order to obtain the fiber block 11 in which a plurality of heat fusion portions are three-dimensionally dispersed, the raw material fiber sheet 10bs (see FIG. 6) may be configured in the same manner, and as described above, the plurality of heat fusion portions may be three-dimensionally The dispersed raw material fiber sheet 10bs can be produced by subjecting a fiber web or a nonwoven fabric mainly composed of thermoplastic fibers to heat treatment such as hot air treatment.

In addition, as described above, the constituent fibers 11F constituting the fiber block 11 have a hydrophilicity of preferably 75 degrees or less with respect to water, but it is preferably non-absorbent, that is, it is difficult to absorb moisture (body fluid such as urine or menstrual blood). Nature. This is in marked contrast to the case where the water-absorbent fiber 12F used in combination with the fiber block 11 has a literal water absorption property. When the fiber 11F is a non-absorbent fiber lacking water absorption, the absorbent core 40 stably exhibits the presence of the fiber block 11 not only in a dry state but also in a wet state when absorbing body fluid. The effect (the shape retention property, the softness, the cushioning property, the compression recovery property, and the crease resistance) are produced. Therefore, as the raw material fiber, a non-absorbent synthetic fiber is preferred.

In the present specification, the term "water absorption" is, for example, a so-called pulp which is easily understood by the manufacturer for water absorption. Similarly, it is also easy to understand that the thermoplastic fiber is non-absorbent. On the other hand, the degree of water absorption of fibers such as synthetic fibers can also be determined by the value of the moisture content measured by the following method. The water-absorbent fiber preferably has a water content of 6% or more, and more preferably 10% or more. On the other hand, the non-absorbent fiber preferably has a moisture content of less than 6%, more preferably less than 4%. In addition, when the moisture content is less than 6.0%, the fiber is judged to be a non-absorbent fiber, and when it is 6.0% or more, the fiber is judged to be a water-absorbent fiber.

<Method for Measuring Moisture Content> The water content was calculated by using the water content test method of JIS P8203. That is, after the fiber sample was allowed to stand in a test chamber at 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 chamber. Thereafter, it was allowed to stand in an electric dryer (for example, manufactured by Isuzu Manufacturing Co., Ltd.) at a temperature of 105 ± 2 ° C for 1 hour to carry out absolute drying treatment of the fiber sample. After the absolute drying treatment, Saran Wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd., in a standard state of a temperature of 20 ± 2 ° C and a relative temperature of 65 ± 2%, to include the state of the fiber sample, A Si silicone (for example, manufactured by Toyota Chemical Co., Ltd.) was placed in a glass drier (for example, manufactured by Tech Jam), and the fiber sample was allowed to stand until the temperature reached 20 ± 2 °C. Thereafter, the constant amount W'(g) of the fiber sample was weighed, and the moisture content of the fiber sample was determined by the following formula. Moisture rate (%) = (W-W'/W') × 100

As the raw material fibers of the constituent fibers 11F of the fiber block 11, as described above, a synthetic fiber made of a thermoplastic and non-absorbent synthetic resin is preferable. Examples of such a preferred synthetic resin (thermoplastic resin) include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamines such as nylon 6, nylon 66; and polyacrylic acid; The polyalkyl methacrylate, the polyvinyl chloride, the polyvinylidene chloride, and the like may be used alone or in combination of two or more. Further, the fiber 11F may be a single fiber comprising a synthetic resin (thermoplastic resin) or a blended polymer obtained by mixing two or more kinds of synthetic resins, or may be a composite fiber. Here, the composite fiber is a synthetic fiber (thermoplastic fiber) obtained by combining two or more kinds of synthetic resins having different compositions by a spinning head and simultaneously spinning, and each of the plurality of components is continuous in the longitudinal direction of the fiber. Constructed in a single fiber and connected to each other. The form of the conjugate fiber has a core-sheath type, a side-by-side type, and the like, and is not particularly limited.

The content of the hydrophilizing agent in the fiber 11F is not particularly limited as long as it is appropriately adjusted depending on the type of the raw material fiber or the hydrophilizing agent, the degree of hydrophilization desired, and the like, and is, for example, a raw material using the above thermoplastic resin as a raw material. When the fiber is used as a hydrophilizing agent and the contact angle of the fiber 11F with water is 75 degrees or less, the fiber is preferably 0.2% by mass or more based on the total mass of the fiber 11F. Further, it is preferably 0.4% by mass or more, more preferably 2.0% by mass or less, still more preferably 1.5% by mass or less. When the content of the hydrophilizing agent is too small, the degree of hydrophilization of the fiber block 11 is lowered, and the above-described effects are not sufficiently exhibited. On the other hand, if the amount of the hydrophilizing agent 11 is too large, the raw material fiber sheet at the manufacturing site of the fiber block 11 is transported. When the production line is polluted.

On the other hand, as the water-absorbent fiber 12F used in combination with the fiber block 11, a hydrophilic and water-absorptive fiber which has been used as a material for forming an absorbent core of such an absorbent article can be used, and for example, conifer pulp or Natural fiber such as wood pulp, cotton pulp or hemp pulp such as broadleaf pulp; modified pulp such as cationized pulp and mercerized pulp; recycled fiber such as copper ammonia fiber and hydrazine; and one of these may be used alone. Or use in combination of 2 or more types.

The contact angle of the constituent fibers 11F (synthetic fibers 11F) of the fiber block 11 with water is preferably at least the contact angle of the water absorbent fibers 12F with water. That is, the hydrophilicity of the synthetic fiber 11F is preferably the same as the hydrophilicity of the water-absorbent fiber 12F or lower than the hydrophilicity of the water-absorbent fiber 12F. By the relationship of the degree of hydrophilicity, the body fluid can further smoothly move from the fiber block 11 to the water-absorbent fiber 12F or in the opposite direction, and the liquid absorbing property of the absorbent core 40 can be expected to be further improved. improve. In order to achieve the relationship between the size of the fiber 11F and the water-absorbent fiber 12F, the degree of hydrophilicity of the fiber 11F by the hydrophilizing agent can be appropriately adjusted. The contact angle of the water-absorbent fiber 12F with water is premised on the contact angle of the fiber 11F with water, and is preferably 60 degrees or less, more preferably 40 degrees or less.

Further, the contact angle of the constituent fibers 11F (synthetic fibers) of the fiber block 11 with water is preferably smaller than the contact angle of the front sheet 2 with water. That is, the hydrophilicity of the fiber 11F is preferably higher than that of the front sheet 2. In the sanitary napkin 1, the liquid absorbed by the front sheet 2 is quickly taken into the absorbent core 40 by the establishment of the relationship of the degree of hydrophilicity, and the absorbent core is further provided by the absorbent core. The liquid diffusion effect in the planar direction of the inside of the body 40, particularly in the above-mentioned portion of the discharge portion located at the central portion of the longitudinal central portion B (see FIG. 1) of the sanitary napkin 1, reducing the front sheet 2 and the absorbent core 40 The liquid holding amount is further excellent in the cushioning property of the opposing portion of the excretory portion and its vicinity after the liquid is absorbed. In order to achieve the contact angle with water, the size relationship between the "front sheet 2" fiber 11F (fiber block 11) and the water-absorbent fiber 12F" is achieved by adjusting the hydrophilicity of the fiber 11F by the hydrophilizing agent. In addition to the degree, the front sheet 2 may be appropriately adjusted by the same hydrophilization treatment as the fiber 11F.

In the absorbent core 40, the mass ratio of the fiber mass 11 to the water-absorbent fiber 12F is not particularly limited as long as the fiber 11F (synthetic fiber containing a hydrophilizing agent) and the water-absorbent fiber 12F are classified according to the fiber block 11. The adjustment may be carried out as appropriate, but the quality of the fiber block 11 and the water absorbent fiber 12F is higher than that of the former (fiber block 11) / the latter (water absorbent fiber 12F) from the viewpoint of more specifically exhibiting the specific effects of the present invention. Preferably, it is 20/80 to 80/20, and further preferably 40/60 to 60/40.

The content of the fiber block 11 in the absorbent core 40 is preferably 20% by mass or more, more preferably 40% by mass or more, and further preferably 80% by mass based on the total mass of the absorbent core 40 in a dry state. Hereinafter, it is more preferably 60% by mass or less. The content of the water-absorbent fiber 12F in the absorbent core 40 is preferably 20% by mass or more, more preferably 40% by mass or more, and more preferably 80% by mass based on the total mass of the absorbent core 40 in a dry state. % or less is further preferably 60% by mass or less.

The basis weight of the fiber block 11 in the absorbent core 40 is preferably 32 g/m ² or more, more preferably 80 g/m ² or more, and further preferably 640 g/m ² or less, and further preferably 480 g/m ² or less. The basis weight of the water-absorbent fiber 12F in the absorbent core 40 is preferably 32 g/m ² or more, more preferably 80 g/m ² or more, and further preferably 640 g/m ² or less, and further preferably It is 480 g/m ² or less.

As described above, the excellent effect of the absorbent core 40, specifically, for example, in any of a dry state and a wet state, is excellent in cushioning property, compression recovery property, liquid introduction property, liquid diffusibility, and the like. The effect is largely determined by the fiber block 11 comprising the fiber 11F containing the hydrophilizing agent, and the distribution of the fiber block 11 in the absorbent core 40 can be effected by the absorbent core 40. The appearance of the effect has a considerable impact.

For example, if the fiber block 11 is present in the case where the absorbent core 40 is halved in the thickness direction (the direction orthogonal to the skin facing surface or the non-skin opposing surface of the absorbent core 40), the sanitary napkin is present. 1 is a relatively close side of the skin of the wearer, that is, the skin facing side of the absorbent core 40 (the side of the front sheet 2), and the fibrous block 11 having a liquid retainability lower than that of the absorbent fiber 12F is present in the wearer. In the vicinity of the skin, the body fluid is smoothly transferred from the skin facing surface side to the non-skin facing surface side (the back sheet 3 side), and the liquid introduction property of the absorbent core 40 is improved, resulting in a reduction in the front side. Since the liquid in the facing surface of the sheet 2 remains, the unpleasant moisturizing feeling or the sticky feeling can be suppressed, and the wearing feeling of the sanitary napkin 1 is improved.

Moreover, the effect of the action (bufferability, liquid absorbing property, etc.) achieved by the absorbent core 40 is affected not only by the distribution state of the fiber block 11 in the absorbent core 40 but also by the alignment of the fiber block 11. Sex is greatly affected. Basically, if the plurality of fiber blocks 11 included in the absorbent core 40 are oriented in the thickness direction of the absorbent core 40 (the direction perpendicular to the skin facing surface or the non-skin opposing surface of the absorbent core 40) When it is randomly aligned, it is preferable to balance the cushioning property, particularly the cushioning property and the compression recovery property in the wet state of the absorbent core 40, at a high level. Here, "the fiber block 11 is randomly aligned with respect to the thickness direction of the absorbent core 40" means focusing on the long axis direction of each of the plurality of fiber blocks 11 (the main body portion 110), that is, the length of the base surface 111. In the case of the direction (the maximum diameter length direction and the diameter direction), the major axis directions of the plurality of fiber blocks 11 included in the absorbent core 40 do not coincide with each other. In the case where a known fiber stacking device having a rotating drum is used and the manufacture of the absorbent core 40 is carried out according to the conventional practice, usually the plurality of fiber blocks 11 included in the absorbent core 40 are opposed to the absorbent core 40. The thickness direction is randomly aligned.

Further, it is preferable that at least a part of the plurality of fiber blocks 11 included in the absorbent core 40 is aligned in the longitudinal direction of the longitudinal direction of the absorbent core 40 in the longitudinal direction of the absorbent core 40. In this case, "aligning in the thickness direction" means that the longitudinal axis direction of the fiber block 11 and the thickness direction of the absorbent core 40 are 45 degrees or less. If the fiber block 11 is aligned in the absorbent core 40 in such a manner that the longitudinal direction of the fiber block 11 is along the thickness direction of the absorbent core 40, the fiber block 11 is not aligned in this manner. For example, the long axis direction of the fiber block 11 and the direction orthogonal to the thickness direction of the absorbent core 40, that is, the fiber block 11 is along the skin facing surface or the non-skin facing surface along the absorbent core 40. In the case where the direction of the surface is aligned, the recovery property of the absorbent core 40 in the wet state can be further improved. It is preferable that all the fiber blocks 11 included in the absorbent core 40 are preferably 30% by mass or more, and more preferably 50% by mass or more. Such as the long axis direction of the fiber block 11 along the absorbent core 40 The orientation of the thickness direction.

As described above, the excellent liquid absorbency (liquid introduction property, liquid diffusibility, etc.) of the absorbent core 40 largely depends on the surface of the body portion 110 of the fiber block 11, that is, the base surface 111 and the skeleton surface 112. The interfiber spaces of the fibers 11F are formed. In this regard, the constituent fibers 11F of the fiber block 11 are preferably oriented in the plane direction of the base surface 111. According to this configuration, a plurality of interfiber spaces constituting the fibers 11F are formed on the base surface 111 of the fiber block 11 (main portion 110), so that the liquid absorbing property of the absorbent core 40 can be further improved. Here, "the direction in which the fibers 11F are aligned to the surface of the base surface 111" means a state in which the fibers 11F extend in the surface direction of the base surface 111. More preferably, the fiber 11F extends in the longitudinal direction of the base surface 111. Further, it is more preferable that the total number of the fibers 11F present on the base surface 111 is preferably 30% or more, more preferably 50% or more, in the plane direction (preferably the longitudinal direction) of the base surface 111.

The absorbent core 40 may contain other components than the fiber block 11 and the water-absorbent fiber 12F, and examples thereof include a water-absorbent polymer. As the water-absorptive polymer, those which are generally in the form of particles or fibers may be used. In the case of using a particulate superabsorbent polymer, the shape may be any of a spherical shape, a block shape, a bag shape, or an unfixed shape. The average particle diameter of the water-absorptive polymer is preferably 10 μm or more, more preferably 100 μm or more, and is preferably 1000 μm or less, and more preferably 800 μm or less. As the water-absorbing polymer, a polymer or copolymer of an acrylic acid or an alkali metal acrylate can be generally used. As an example, polyacrylic acid and its salt, and polymethacrylic acid and its salt are mentioned.

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

The absorbent core 40 can be produced in the same manner as an absorbent core comprising such a fibrous material. As described above, the fiber block 11 can be cut by a cutter or the like by using a raw material fiber sheet (the same composition as the fiber block 11 and having a size larger than the fiber block 11) as shown in FIG. The fiber block 11 produced in this manner is cut and cut in two directions, and the plurality of fiber blocks 11 are formed into a "fixed shape fiber assembly" having a uniform shape and size (for example, the body portion 110 has a rectangular parallelepiped shape). . The absorbent core 40 including the fiber block 11 and the water absorbent fiber 12F can be produced, for example, by using a known fiber stacking device having a rotary drum. Typically, the fiber stacking device includes a rotating drum having a concave portion for collecting on the outer peripheral surface, and a material for transporting the raw material (fiber block 11 and water-absorbent fiber 12F) of the absorbent core 40 to the collecting recess. a conduit of the flow path that rotates the drum about the axis of rotation along the circumference of the drum and conveys the air flow (vacuum air) generated in the flow path by suction from the inner side of the drum The raw material fibers are deposited in the collecting recess. The fiber deposit formed in the collecting recess by the fiber stacking step is an absorbent core 40. The basis weight of the absorbent core 40 is preferably 100 g/m ² or more, more preferably 200 g/m ² or more, and further preferably 800 g/m ² or less, and further preferably 600 g/m ^{2 .} the following.

The absorbent core 40 (absorbent body 4) having the above-described configuration is soft and excellent in cushioning property, and is excellent in compression recovery property, and is excellent in external force responsiveness, and is quickly restored to its original state when external force is released. The characteristics of such an absorbent core can be evaluated on the basis of a compression workload (WC) and a compression recovery ratio (RC). The compression workload is a measure of the cushioning property of the absorbent core, and the larger the WC value, the higher the cushioning property can be evaluated. The compression recovery ratio is a measure of the degree of recovery when the absorbent core is compressed and then released from the compressed state. The larger the RC value, the higher the compression recovery property can be evaluated. Further, in consideration of the task of absorbing the liquid-absorbing absorbent core 40, the absorbent core 40 preferably has a WC value not only in the dry state but also in the case where the absorbed body fluid or the like is wet. The RC value is large. In order that the absorbent core 40 has such a property in a wet state, as described above, it is effective to use a synthetic fiber containing a hydrophilizing agent as the constituent fiber 11F of the fiber block 11, if the synthetic fiber is non-absorbent and thermoplastic Better.

<Measurement Method of Compression Workload (WC) and Compression Recovery Rate (RC)> It is known that the compression workload (WC) and compression recovery ratio (RC) of the absorbent core 40 can be KES manufactured by Gado Technology Co., Ltd. (Kawabata evaluation system, Kawabata evaluation system) The measured value is expressed (Reference: Standardization and analysis of texture evaluation (2nd edition); author Kawabata Hiroshi; issued on July 10, 1980). Specifically, the compression work amount and the compression recovery rate can be measured using an automated compression test apparatus KES-FB3-AUTO-A manufactured by Addo Technology Co., Ltd. The order of measurement is as follows. A quaternary quadrangular shape of 195 mm × 68 mm (absorber not wrapped by a packaged material, that is, an absorbent core) was prepared and mounted on a test stand of a compression test apparatus. Then, the sample was compressed between steel sheets having a circular plane having an area of 2 cm ² . The compression speed was set to 0.01 cm/sec, and the maximum compression load was set to 490.2 mN/cm ² . The recovery process is also measured at the same speed. The compression workload (WC) is expressed by the following equation. In the formula, T _m , T _o and P respectively represent the thickness at 490.2 mN/cm ² (4.9 kPa) load, the thickness at 4.092 mN/cm ² (49 Pa) load, and the load at the time of measurement (mN/cm ^{2 )} ). Further, the compression recovery ratio (RC) is expressed as [WC'/WC] × 100 as a ratio of the compression workload (WC) at the time of compression to the compression recovery workload (WC') when the self-compression state is restored to the original state. .

[Number 1]

In addition, the "absorbent core in a dry state" which is a measurement target of the above-mentioned measurement method is prepared by allowing the absorbent core to be measured to stand in an environment of a temperature of 23 ° C and a relative humidity of 50 % RH for 24 hours. Moreover, the "absorbent core in a wet state" which is the measurement target of the said measuring method is adjusted as follows. The absorbent core in a dry state is horizontally placed so that the opposite side of the skin becomes the upper side, and a cylindrical acrylic resin sheet having an injection opening having a diameter of 1 cm at the bottom is superposed on the absorbent core. On the opposite side of the skin, 5.0 g of defibrinated horse blood was injected from the injection port, and this state was maintained for 1 minute after the injection. Furthermore, the defibrinated horse blood produced by the defibrinated horse blood of Japan, which is an absorbent core to be measured, is adjusted to have a viscosity of 8 cp at a liquid temperature of 25 ° C, and The viscosity is a viscosity when the rotor of the rotor name L/Adp (rotor code 19) is measured at a rotational speed of 30 rpm in a TVB-10M type viscometer manufactured by Toki Sangyo Co., Ltd. In addition, Saran Wrap (registered trademark) piece obtained by cutting Saran Wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd. into 4 cm × 4 cm was used in order to prevent the measurement device from being wet. The injection point of the defibrinated horse blood corresponding to the measurement target (absorbent core) and the portion around the peripheral portion of the measurement device are covered.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments and can be appropriately changed. For example, in the above embodiment, the absorber 4 includes the absorbent core 40 and the packaged core material 41 coated thereon, but the packaged core material 41 may be omitted. Further, the absorbent core of the present invention may not be a fiber aggregate in which the fiber block (synthetic fiber aggregate) contained therein is a fixed shape such as the fiber block 11, as long as it does not deviate from the gist of the present invention. Further, in addition to the fiber assembly including the fixed shape, a fiber aggregate having an unfixed shape may be contained in a very small amount. The absorbent article of the present invention broadly comprises an absorbent article for exhalation of bodily fluids (urine, dilute, menstrual blood, sweat, etc.) discharged from the human body, in addition to the above-mentioned menstrual sanitary napkin, including physiological shorts and a fixed strap. The so-called unfolding type diaper, the pant type disposable diaper, the incontinence pad, and the like. The following appendix is further disclosed in the above embodiment of the present invention.

<1> an absorbent body comprising a fiber block containing synthetic fibers and a water-absorbent fiber, wherein a plurality of the fiber blocks are entangled with each other or the fiber block and the water-absorbent fiber are intertwined with each other, and the fiber block has a relative orientation The two basic surfaces and the main body portion formed by dividing the skeleton surface intersecting the two basic surfaces, and the synthetic fiber contains a hydrophilizing agent. <2> The absorbent according to the above <1>, wherein the synthetic fiber has a contact angle with water of 75 degrees or less, preferably 70 degrees or less, more preferably 60 degrees or less, still more preferably 50 degrees or less. <3> The absorbent according to the above <1> or <2>, wherein a contact angle of the synthetic fiber with water is at least a contact angle of the water absorbent fiber with water. The absorbent body according to any one of the above-mentioned <1>, wherein the synthetic fiber is a non-absorbent fiber. The absorbent body according to any one of the above-mentioned items, wherein the total area of the two basic faces is larger than the total area of the skeleton faces. The absorbent body according to any one of the above-mentioned <1> to <5> wherein the number of per unit areas of the fiber end portions of each of the base surface and the skeleton surface is present in the skeleton surface. The above number is more than the above number present in the fundamental plane. <7> The <6> of the absorbent core, wherein said fiber per unit amount of the end portion of the area of the above-described _{fundamentals. 1} and the number N per unit area of said fiber end face portion of the skeleton is the ratio of N ₂ N ₁ of /N ₂ is 0 or more and 0.90 or less, preferably 0.05 or more and 0.60 or less. <8> The absorbent body according to the above <6> or <7>, wherein the number of the unit ends of the fiber ends of the basic surface is 0/mm ² or more, 8 pieces/mm ² or less, preferably 3 / mm ² or more, 6 / mm ² or less. The absorbent body according to any one of the above-mentioned <6>, wherein the number of the unit ends of the fiber ends of the skeleton surface is 5 pieces/mm ² or more and 50 pieces/mm ² or less. It is preferably 8 pieces/mm ² or more and 40 pieces/mm ² or less.

The absorbent body according to any one of the above aspects, wherein the fiber block has a fiber comprising a fiber extending outward from the body portion and having a fiber density lower than that of the body portion. And at least one of the extended fiber portions is an extended fiber bundle portion including a plurality of fibers extending from the main body portion. The absorbent body according to any one of <1> to <10> wherein the body portion is formed in a rectangular parallelepiped shape. The absorbent body according to any one of the above aspects, wherein the plurality of the fiber blocks included in the absorbent body are randomly aligned with respect to a thickness direction of the absorbent body. The absorbent body according to any one of the above aspects, wherein the base surface has a shape that is longer in one direction, and at least a part of the plurality of the fiber blocks included in the absorbent body is The longitudinal direction of the base surface is aligned along the thickness direction of the absorber. The absorbent body according to any one of the above aspects, wherein the fiber mass and the water-absorbent fiber have a mass ratio of 20/80 to 80/20 as compared with the former/the latter. The absorbent body according to any one of the above aspects, wherein the constituent fibers of the fiber block are aligned in a plane direction of the basic surface.

The absorbent body according to any one of the above-mentioned items, wherein the fiber block is combined with the other fiber block or the water-absorbent fiber by entanglement in the absorbent body, It exists in a state of being in contact with other fibrous blocks or the above-mentioned water-absorbing fibers. <17> The absorbent according to the above <16>, wherein the total number of the fiber blocks combined by the entanglement and the entangled state is preferably half of the total number of the fiber blocks in the absorbent body The above is more preferably 70% or more, and still more preferably 80% or more. The absorbent body of any one of the above-mentioned <1> to <17>, wherein the total number of the fiber blocks having a joint portion with the other fiber block or the water absorbent fiber is preferably 70% or more, and further Preferably, 80% or more of the bonds are formed by the entanglement of the fibers. The absorbent body according to any one of <1> to <18> wherein the fiber block is derived from a nonwoven fabric. The absorbent according to any one of the above-mentioned <1>, wherein the hydrophilizing agent comprises an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. One or two or more of the group consisting of the agents. <21> The absorbent according to <20> above, wherein the hydrophilizing agent comprises an anionic surfactant. <22> The absorbent according to the above <21>, wherein the anionic surfactant contains an alkylsulfosuccinate.

<23> An absorbent article comprising the absorbent body according to any one of the above <1> to <22>. <24> The absorbent article according to the above <23>, wherein the one surface side of the absorbent body is provided with a liquid-permeable front sheet, and the fiber block is present in the case where the absorbent body is halved in the thickness direction. The side closer to the side of the front sheet is relatively close. <25> The absorbent article according to the above <23>, wherein the absorbent article and the front sheet disposed on the opposite side of the skin of the absorbent body, the contact angle of the synthetic fiber with water is less than the above The contact angle between the front sheet and the water is equal to or higher than the contact angle of the water-absorbent fiber with water. [Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples.

[Examples 1 to 5] An absorbent core was produced, and samples of the absorbent bodies of the respective examples were prepared. Specifically, a fiber block and a water-absorbent fiber are used as the fiber material of the absorbent core, and a known fiber stacking device is used and manufactured in accordance with the conventional practice. The production of the fiber block was carried out by cutting the raw material fiber sheet into a small square shape according to Fig. 6 . As the raw material fiber sheet of the fiber block, a non-absorbent thermoplastic fiber comprising a polyethylene resin fiber and a polyethylene terephthalate resin fiber (non-absorbent fiber, fiber diameter of 1.8 μm) is used as a base of the constituent fiber. A hot air non-woven fabric (having a fiber sheet constituting a heat fusion portion of fibers) having a thickness of 21 g/m ² and a thickness of 0.6 mm. The constituent fibers of the fiber block are formed by adhering the surface hydrophilizing agent to the film as a non-absorbent thermoplastic fiber as a raw material fiber. In Examples 1 to 4, a composition A having the following composition with respect to the constituent fiber mass of the fiber block was used as a hydrophilizing agent. Further, in Example 5, a composition A and a commercially available surfactant (Pelex OT-P; manufactured by Kao Co., Ltd.) were used as a hydrophilizing agent, and the amount of the hydrophilizing agent used was relative to the fiber block. The fiber mass was set to 0.4% by mass in the former and 0.2% by mass in the latter. A conifer bleached kraft pulp (NBKP) having a fiber diameter of 2.2 μm was used as the water absorbent fiber. The fiber block (fixed-shaped synthetic fiber assembly) used in the absorbent core has a body portion having a rectangular parallelepiped shape as shown in Fig. 5 (a), and the short side 111a of the base surface 111 is 0.8 mm, and the long side 111b is 3.9 mm, thickness T is 0.6 mm. Further, the number of the unit ends of the fiber ends in the base surface 111 was 3.2 / mm ² , and the number of the fiber ends in the skeleton faces 112 per unit area was 19.2 / mm ² . In the absorbent core of each of the examples, the fiber masses are densely distributed and uniformly distributed.

(Composition of the composition A) ・Alkyl phosphate potassium salt (a potassium hydroxide neutralized product of GRIPPER 4131 manufactured by Kao Co., Ltd.) 25% by mass ・Sodium sulfosuccinate sodium salt (Kao Co., Ltd.) Made of Pelex OT-P) 10% by mass ・Alkyl (octadecyl) betaine (Amphitol 86B manufactured by Kao Co., Ltd.) 15% by mass ・Polyoxyethylene (additional molar number: 2) octadecane 30% by mass of amidoxime (Amisol SDE manufactured by Kawaken Fine Chemicals) ・Polyoxyethylene, polyoxypropylene-modified anthrone (X-22-4515 manufactured by Shin-Etsu Chemical Co., Ltd.) 20% by mass

[Comparative Example 1] The absorbent core of the commercially available menstrual sanitary napkin (trade name "Tanom Pew Slim 23cm" manufactured by Jiaolian Co., Ltd.) was directly used as the absorbent body of Comparative Example 1. The absorbent core system of Comparative Example 1 was mixed with a cellulose-based fiber (hydrophilic fiber), and did not contain a fiber block.

[Comparative Example 2] A nonwoven fabric sheet having an unfixed shape was used as a fiber block, and a hot air step was applied to the absorbent core, and the nonwoven fabric sheets included in the absorbent core were thermally fused to each other. The absorbers were produced in the same manner as in 1 to 5. In the hot air step of the above-mentioned absorbent core, a mixed assembly of non-woven fabric and pulp fibers (length 210 mm × width 66 mm) is placed in an electric dryer (for example, manufactured by Isuzu Manufacturing Co., Ltd.) at a temperature of 140 ° C. The glass sheets were allowed to stand for 30 minutes, and the nonwoven sheets were thermally fused to each other. The non-woven fabric sheet of the unfixed shape to be used is produced by pulling in the same direction as the hot air non-woven fabric used in the embodiment, and has a diameter of approximately 25 mm in plan view. Further, in Comparative Example 2, the above composition A was used as a hydrophilizing agent applied to the constituent fibers of the nonwoven fabric sheet.

[Performance Evaluation] With respect to the absorbers of the respective examples and comparative examples, the compression work amount (d-WC) in a dry state, the compression work amount (w-WC) in a wet state, and a dry state were respectively measured by the above method. The compression recovery rate (d-RC) and the compression recovery rate (w-RC) in the wet state. The results are shown in Table 1 below.

[Table 1]

As shown in Table 1, the absorbent body of each of the examples contained a hydrolyzed fixed-shaped fibrous block comprising a synthetic fiber containing a hydrophilizing agent and having two basic faces and a skeleton face intersecting the two basic faces. Since the division is formed, compared with Comparative Examples 1 and 2 which do not include such a fiber block, the compression work amount is large in any of the dry state and the wet state, and the compression recovery rate is also in the dry state and A higher value is displayed in any of the wet states. In particular, according to the comparison between the respective examples and the comparative example 2, it is found that in order to obtain an absorbent body which is excellent in cushioning property even in a wet state, it is effective to carry out hydrophilicity in addition to the fiber mass in the absorbent body. In addition to the chemical treatment, the fiber blocks are also fixed in shape and the fiber blocks are bonded to each other by entanglement. [Industrial availability]

The absorption system of the present invention is excellent in cushioning property and compression recovery property, and is excellent in external force responsiveness and can be flexibly deformed, so that the wearing feeling can be improved when applied to an absorbent article. Further, the absorbent body of the present invention exhibits excellent effects not only before the liquid absorption but also in the wet state after the liquid is absorbed and retained. Moreover, since the absorbent article of the present invention has such a high-quality absorbent body, it is excellent in wearing feeling and leakproofness.

1‧‧‧Sanitary cotton

2‧‧‧Front sheet

3‧‧‧Back sheet

4‧‧‧Acceptor

5‧‧‧Absorbing ontology

5W‧‧‧wing

6‧‧‧Side sheet

10bs‧‧‧Material fiber sheet

11‧‧‧Fiber blocks

11A‧‧‧Fiber block

11B‧‧‧Fiber block

11F‧‧‧constituting fiber

11Z‧‧‧Overlapping of multiple fiber blocks

12F‧‧‧Water-absorbent fiber

40‧‧‧Absorbable core

41‧‧‧Package

110‧‧‧ Body Department

111‧‧‧ fundamentals

111a‧‧‧ Short side

111b‧‧‧Longside

112‧‧‧Mask face

113‧‧‧Extension of the fiber department

113S‧‧‧Extension of the fiber bundle

A‧‧‧ front area

B‧‧‧Central Region

BL‧‧‧ Junction

C‧‧‧ rear area

D1‧‧‧1st direction

D2‧‧‧2nd direction

F‧‧‧External force

L1‧‧‧ length

L1a‧‧ interval

L2‧‧‧ length

L2a‧‧‧ interval

T‧‧‧ thickness

X‧‧‧ portrait

Y‧‧‧ horizontal

Z‧‧‧ Thickness direction

Fig. 1 is a plan view schematically showing a skin facing surface side (front sheet side) of an example of a menstrual sanitary napkin which is one embodiment of the absorbent article of the present invention. Fig. 2 is a cross-sectional view schematically showing a cross section taken along line I-I of Fig. 1. Fig. 3 is a schematic perspective view showing a part of an absorbent core provided in the absorbent article shown in Fig. 1. Fig. 4 is a view schematically showing a state of deformation of the absorbent core shown in Fig. 3 during compression. 5(a) and 5(b) are schematic perspective views of the body portion of the fiber block of the present invention, respectively. Fig. 6 is an explanatory view showing a method of producing the fiber block of the present invention. Fig. 7 (a) is an electron micrograph of an example of the fiber block of the present invention (observation magnification: 25 times), and Fig. 7 (b) is a fiber block of the electron micrograph as a fiber contained in the absorber shown in Fig. 2. The block schematically represents the map.

Claims (25)

An absorbent body comprising a fiber block containing synthetic fibers and a water-absorbing fiber, and a plurality of the fiber blocks are entangled with each other or the fiber block and the water-absorbent fiber are intertwined with each other, and the fiber block has two basic elements The surface and the body portion formed by the skeleton surface intersecting the two basic surfaces are divided, and the synthetic fiber contains a hydrophilizing agent. The absorbent according to claim 1, wherein the synthetic fiber has a contact angle with water of 75 degrees or less. The absorbent body according to claim 1, wherein the contact angle of the synthetic fiber with water is at least the contact angle of the water absorbent fiber with water. The absorbent body of claim 1, wherein the synthetic fiber is a non-absorbent fiber. The absorbent body of claim 1, wherein the total area of the two basic faces is greater than the total area of the skeleton faces. The absorbent body according to claim 1, wherein the number of per unit areas of the fiber end portions of each of the base surface and the skeleton surface is greater than the base surface. The absorbent body according to claim 6, wherein the ratio N ₁ /N ₂ of the number N ₁ per unit area of the fiber end portion of the base surface to the number N ₂ per unit area of the fiber end portion of the skeleton surface is 0 or more and 0.90 or less. The absorbent body according to claim 6, wherein the number of the unit ends of the fiber ends of the base surface is 0/mm ² or more and 8 pieces/mm ² or less. The absorbent body according to claim 6, wherein the number of the unit ends of the fiber ends of the skeleton surface is 5 pieces/mm ² or more and 50 pieces/mm ² or less. The absorbent body according to claim 1, wherein the fiber block has a fiber comprising a fiber extending outward from the body portion and having a fiber density lower than that of the body portion, and at least one of the fiber portions The member is a fiber bundle portion including a plurality of fibers extending from the body portion. The absorbent body of claim 1, wherein the body portion is formed in a rectangular parallelepiped shape. The absorbent body according to claim 1, wherein the plurality of the fiber blocks included in the absorbent body are randomly aligned with respect to a thickness direction of the absorbent body. The absorbent body of claim 1, wherein the base surface has a shape that is longer in one direction, and at least a portion of the plurality of the fiber blocks included in the absorbent body is along the length of the base surface along the thickness of the absorbent body Directional alignment. The absorbent body according to claim 1, wherein the mass ratio of the fiber block to the water-absorbent fiber is 20/80 to 80/20 as compared with the former/the latter. The absorbent body of claim 1, wherein the constituent fibers of the fiber block are oriented in a plane direction of the above-mentioned basic face. The absorbent body according to claim 1, wherein the fiber block is in the absorbent body, and is combined with other fiber blocks or the water-absorbing fibers by entanglement, and is also in a state of being entangled with other fiber blocks or the water-absorbing fibers. presence. The absorbent body according to claim 16, wherein the total number of the fiber blocks combined by the entanglement and the entangled fiber block is more than half of the total number of the fiber blocks in the absorbent body. The absorbent body according to claim 1, wherein 70% or more of the total number of the fiber blocks having a joint portion with the other fiber block or the water-absorbent fiber is formed by the entanglement of fibers. The absorbent body of claim 1, wherein the fiber block is derived from a nonwoven fabric. The absorbent according to claim 1, wherein the hydrophilizing agent comprises one or two selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. the above. The absorbent of claim 20, wherein the hydrophilizing agent comprises an anionic surfactant. The absorbent of claim 21, wherein the anionic surfactant comprises an alkyl sulfosuccinate. An absorbent article comprising the absorbent body according to any one of claims 1 to 22. The absorbent article according to claim 23, wherein the front side of the absorbent body is provided with a liquid-permeable front sheet, and the fibrous block is present in the front side when the absorbent body is halved in the thickness direction. The side of the sheet is relatively close. The absorbent article according to claim 23, comprising: the absorbent body; and a front sheet disposed on the opposite side of the skin of the absorbent body, wherein a contact angle of the synthetic fiber with water is smaller than a contact angle of the front sheet with water Further, it is at least the contact angle of the water-absorbent fiber with water.