WO2019069882A1

WO2019069882A1 - Absorbent and absorbent article

Info

Publication number: WO2019069882A1
Application number: PCT/JP2018/036769
Authority: WO
Inventors: 湧太辰巳; 学松井
Original assignee: 花王株式会社
Priority date: 2017-10-03
Filing date: 2018-10-02
Publication date: 2019-04-11
Also published as: RU2769865C2; RU2020112146A3; CN111031986B; CN111031986A; RU2020112146A

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 for an absorbent article.

Absorbent articles such as disposable diapers and sanitary napkins generally have a top sheet relatively arranged closer to the skin of the wearer and a back sheet relatively arranged farther away from the skin of the wearer And the absorber interposed between both sheets. This absorbent body is typically composed mainly of hydrophilic fibers (water absorbent fibers) such as wood pulp, and often composed of water absorbent polymer particles. With regard to an absorbent used for an absorbent article, improvement of various properties such as flexibility (cushioning), compression recovery, shape retention, etc. is a major issue.

As an improvement technique of the absorber, for example, in Patent Document 1, in an absorber mainly composed of pulp fibers and a water absorbing polymer, a hydrophobic fiber having a longer fiber length than pulp fibers, for example, synthesis of non-hydrophilized polypropylene etc. It is described that the fibers are dispersed in the pulp fibers. According to Patent Document 1, there is no reversion of body fluid due to the presence of hydrophobic fibers, and the strength of the absorber is increased by entangling hydrophobic fibers having a long fiber length with pulp fibers. It is said that the shape retention can be maintained well.

Further, in Patent Document 2, in an absorbent mainly comprising pulp fibers and a water absorbing polymer, hydrophilic long fibers having a fiber length longer than pulp fibers, such as rayon, cotton, wool, hemp, etc., are dispersed in the pulp fibers. It is stated that According to Patent Document 2, such an absorbent body can stably maintain its shape before and after body fluid absorption, and since the hydrophilic long fibers are dispersed without heat treatment, such an absorbent body can be used. As for the whole body, feeling is maintained suitably, and it is said that there is little possibility of causing fluid absorption inhibition.

Further, Patent Document 3 describes an absorbent containing a non-woven fabric piece to which a three-dimensional structure has been imparted by bonding between fibers in advance, which contains heat-fusion fibers, and a hydrophilic fiber. The non-woven fabric piece of this three-dimensional structure is manufactured by crushing the non-woven fabric into small pieces using a crushing means such as a cutter mill method, and due to such a manufacturing method, FIGS. It has an irregular shape as described in 3, and has substantially no part that can be regarded as a flat surface. Patent Document 3 describes, as a preferred embodiment of the absorber described in the same document, one obtained by heat-fusing non-woven fabric pieces. According to the absorbent body described in Patent Document 3, since the non-woven fabric piece has a three-dimensional structure, a void is formed inside the absorbent body, and the restorability when absorbing water is improved, and as a result, the water absorption performance is improved. It is supposed to be.

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

Japanese Patent Application Publication No. 2004-73698 Japanese Patent Application Laid-Open No. 6-98909 JP 2002-301105 A Unexamined-Japanese-Patent No. 1-156560

The present invention relates to an absorbent comprising a fiber mass containing synthetic fibers and a water-absorbent fiber, wherein a plurality of the fiber masses or the fiber mass and the water-absorbent fiber are mutually entangled. The fiber mass has a main body defined by two opposing base surfaces and a skeletal surface intersecting the two base surfaces. The synthetic fiber contains a hydrophilizing agent.
The present invention also relates to an absorbent article comprising the above-mentioned absorbent of the present invention.

FIG. 1 is a plan view schematically showing a skin facing surface side (surface sheet side) of an example of a sanitary napkin which is an embodiment of the absorbent article according to the present invention with a part broken. FIG. 2 is a cross-sectional view schematically showing a cross section taken along line II of FIG. FIG. 3 is a schematic perspective view of a portion of the absorbent core included in the absorbent article shown in FIG. FIG. 4 is a view schematically showing a deformed state of the absorbent core shown in FIG. 3 at the time of compression. Fig.5 (a) and FIG.5 (b) are typical perspective views of the main-body part in the fiber lump which concerns on this invention, respectively. FIG. 6 is an explanatory view of a method of producing a fiber mass according to the present invention. FIG. 7 (a) is an electron micrograph (observation magnification 25 times) of an example of the fiber mass according to the present invention, and FIG. 7 (b) is the electron as a fiber mass contained in the absorber shown in FIG. It is the figure which showed typically the fiber lump of the microscope picture.

Detailed Description of the Invention

Each of the absorbers described in

Patent Documents

1 and 2 further contains only cellulose-based fibers as a constituent fiber, in addition to cellulose-based fibers such as pulp fibers and further includes hydrophilic long fibers such as synthetic fibers or rayon. The rigidity is higher than that of the absorbent body, which may improve various properties such as cushioning property and compression recovery property, but a plurality of contained synthetic fibers are present independently, The effect of improving the properties is not sufficient because they do not form a single block, and therefore, when applied to an absorbent article, there is a risk that the fit is likely to be insufficient. In particular, after the absorption of body fluids such as urine and menstrual blood, the occurrence of such inconvenience is remarkable.

On the other hand, in any of the absorbers described in

Patent Documents

3 and 4, since the synthetic fibers contained therein are synthetic fiber aggregates called non-woven fabric pieces or fine webs, improvement of cushioning properties and the like can be expected. However, as described above, the synthetic fiber assembly contained in the absorbers described in

Patent Documents

3 and 4 is produced by grinding a non-woven fabric mainly composed of synthetic fibers into small pieces, or peeling off or tearing off. Because they are irregular, their shapes and sizes are not uniform, and due to that, when they are mixed with pulp fibers etc., it is difficult to obtain uniform mixing of both, and the desired effect May not be obtained. In addition, as in the preferred embodiment of the absorber described in Patent Document 3, when all the synthetic fiber aggregates contained in the absorber are thermally fused to one another, the movement of the assembly itself is restricted as a result. As a whole, the hardness is increased, and various properties such as flexibility may be reduced.

Therefore, the present invention has an excellent cushioning property and compression recovery property, can be flexibly deformed responsive to external force, and can improve the wearing feeling when applied to an absorbent article, and the absorbent body The present invention relates to an absorbent article using an absorbent.

Hereinafter, the absorbent body of the present invention, together with the absorbent article of the present invention provided with the same, will be described based on those preferred embodiments with reference to the drawings. The sanitary napkin 1 which is one Embodiment of the absorbent article of this invention is shown by FIG.1 and FIG.2. The napkin 1 includes an absorbent body 4 for absorbing and holding a body fluid, a liquid-permeable surface sheet 2 disposed on the skin-facing side of the absorbent body 4 and capable of contacting the wearer's skin, and a non-absorbent absorbent body 4. And a back sheet 3 having low liquid permeability that is disposed on the side facing the skin. As shown in FIG. 1, the napkin 1 has a longitudinal direction X corresponding to the longitudinal direction of the wearer and extending from the ventral side of the wearer to the dorsal side via the crotch, and a lateral direction Y orthogonal thereto. Also, in the longitudinal direction X, the longitudinal central area B including the excretory part opposing part (excretion point) facing the excretory part such as the vulva of the wearer, and the ventral side of the wearer And a rear area C disposed on the back side (rear side) of the wearer with respect to the excretory part facing portion.

In the present specification, the "skin-facing surface" is a surface of an absorbent article or a component thereof (for example, the absorbent body 4) that is directed to the skin side of the wearer when wearing the absorbent article, It is a side close to the skin, and the "non-skin facing surface" is the side opposite to the skin side when wearing the absorbent article, ie, the side relatively away from the wearer's skin, when the absorbent article or component thereof is worn It is a face to be In addition, "at the time of wear" here means the state in which the normal proper wearing position, ie, the correct wearing position of the said absorbent article, was maintained.

The napkin 1 is, as shown in FIG. 1, outward in the transverse direction Y from the absorbent main body 5 having a shape long in the longitudinal direction X and both side portions along the longitudinal direction X of the longitudinal central region B in the absorbent main body 5. It has a pair of

wing parts

5W and 5W which extend. The absorbent main body 5 is a main part of the napkin 1 and includes the front sheet 2, the back sheet 3 and the absorbent body 4 described above, and in the longitudinal direction X, the front area A, the longitudinal central area B and the rear area C It is divided into three.

When the absorbent article has wings as in the case of the napkin 1, the longitudinal central area in the absorbent article of the present invention is a wing in the longitudinal direction (longitudinal direction, X direction in the figure) of the absorbent article. When the napkin 1 is taken as an example, it means an area sandwiched between a base along the longitudinal direction X of one wing 5W and a base along the longitudinal direction X of the other wing 5W. Moreover, the vertical central area in the absorbent article which does not have a wing part means the area | region located in the middle when the absorbent article is longitudinally divided into three.

In the napkin 1, the absorbent body 4 is configured to include a liquid absorbent absorbent core 40 and a liquid permeable core wrap sheet 41 that covers the outer surface of the absorbent core 40. The absorbent core 40 has a long shape in the longitudinal direction X in plan view as shown in FIG. 1 like the absorbent main body 5, and the longitudinal direction of the absorbent core 40 is one in the longitudinal direction X of the napkin 1. The width direction of the absorbent core 40 coincides with the lateral direction Y of the napkin 1. The absorbent core 40 and the core wrap sheet 41 may be joined by an adhesive such as a hot melt adhesive. In addition, the absorber 4 does not need to contain the core wrap sheet 41, and in that case, the absorbent core 40 is used for the absorbent article as the absorber 4 as it is.

Thus, the absorbent body 4 which is one embodiment of the absorbent body of the present invention can be indirectly applied to human skin by being incorporated into an absorbent article such as the napkin 1, that is, a member such as the surface sheet 2 It is used by being indirectly applied to the skin via the skin, has a skin-facing surface and a non-skin-facing surface on the opposite side, and corresponds to the longitudinal direction X corresponding to the front-rear direction of the wearer of the napkin 1 It has an orthogonal horizontal direction Y, and is divided into three regions in the longitudinal direction X: front area A, vertical central area B, and rear area C. In addition to indirectly applying to the skin of such a person, the absorber 4 can also be used by directly applying it.

In the napkin 1, the core wrap sheet 41 is one continuous sheet having a width twice to three times the length of the absorbent core 40 in the transverse direction Y, and as shown in FIG. The entire surface of the elastic core 40 facing the skin is covered, and extends outward from both side edges along the longitudinal direction X of the absorbent core 40 in the lateral direction Y, and the extended portion is below the absorbent core 40 It is rolled down to cover the entire non-skin facing surface of the absorbent core 40. In the present invention, the core wrap sheet may not be such a single sheet, for example, one skin side core wrap sheet for covering the skin facing surface of the absorbent core 40, and the skin side. The core wrap sheet may be separate from the core wrap sheet, and may include two sheets with one non-skin side core wrap sheet that covers the non-skin facing surface of the absorbent core 40.

As shown in FIG. 2, the top sheet 2 covers the entire area of the skin facing surface of the absorber 4. On the other hand, the back sheet 3 covers the whole area of the non-skin facing surface of the absorbent body 4 and extends outward from both side edges along the longitudinal direction X of the absorbent body 4 in the lateral direction Y, together with side sheets 6 described later It forms a side flap. The side flap portion is a portion of the napkin 1 which is a member extending outward in the lateral direction Y from the absorbent body 4. The back sheet 3 and the side sheet 6 are bonded to each other at the extension from the side edges along the longitudinal direction X of the absorber 4 by a known bonding means such as an adhesive, heat seal, ultrasonic seal or the like. Each of the top sheet 2 and the back sheet 3 may be bonded to the absorber 4 by an adhesive. As the top sheet 2 and the back sheet 3, various kinds of materials conventionally used in absorbent articles such as sanitary napkins can be used without particular limitation. For example, as the surface sheet 2, nonwoven fabric of a single layer or a multilayer structure, an apertured film, etc. can be used. A moisture permeable resin film or the like can be used as the back sheet 3.

As shown in FIG. 1, the side flaps largely project outward in the longitudinal central area B in the lateral direction Y, whereby a pair of left and right sides along the longitudinal direction X of the absorbent main body 5 are provided.

Wings

5W and 5W are extended. The wing portion 5W has a substantially trapezoidal shape in which the lower base (the side longer than the upper base) is located on the side of the absorbent main body 5 in a plan view as shown in FIG. The wing portion adhesive portion (not shown) for fixing the wing portion 5W to the clothes such as the shorts is formed. The wing portion 5W is used by being folded back to the non-skin facing surface (outer surface) side of the crotch portion of the clothes such as shorts. The wing adhesion portion is covered with a release sheet (not shown) made of film, nonwoven fabric, paper or the like before its use. Further, on the skin opposing surface of the absorbent main body 5, that is, on both sides along the longitudinal direction X in the skin opposing surface of the surface sheet 2, a pair is provided so as to overlap the left and right sides along the longitudinal direction X of the absorber 4 in plan view. The

side sheets

6, 6 are disposed over substantially the entire length of the absorbent main body 5 in the longitudinal direction X. The pair of

side sheets

6 and 6 are joined to other members such as the top sheet 2 by known joining means such as an adhesive at joining lines (not shown) extending in the longitudinal direction X, respectively.

As one of the main features of the napkin 1, an absorbent body 4, in particular, an absorbent core 40 as a main component of the absorbent body 4 can be mentioned. A portion of the absorbent core 40 is shown in FIG. As shown in FIGS. 2 and 3, the absorbent body 4, more specifically, the absorbent core 40 includes a fiber mass 11 including a plurality of fibers (synthetic fibers) 11 F and a water absorbing fiber 12 F. While the fiber mass 11 is a fiber aggregate in which the fibers 11F are intentionally accumulated and integrated, the water absorbent fibers 12F are not intentionally integrated but may be independently present. It is present in the absorbent core 40. The fiber mass 11 mainly contributes to the improvement of the softness, cushioning property, compression recovery property, shape retention property and the like of the absorbent core 40. On the other hand, the water absorbent fiber 12F mainly contributes to the improvement of the liquid absorptivity and shape retention of the absorbent core 40, and the like. The absorbent core 40 can be substantially referred to as the absorbent 4 itself, and the description of the absorbent core 40 below is appropriately applied as the description of the absorbent 4 unless otherwise specified. That is, the present invention includes the case where the absorbent does not include the core wrap sheet and is formed only of the absorbent core, in which case the absorbent and the absorbent core have the same meaning.

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

Thus, the sheet-like fiber mass which is a preferred embodiment of the fiber mass according to the present invention is not configured to accumulate a plurality of fibers to form the sheet pieces, but from the sheet pieces Also, it is manufactured by cutting a large size fiber sheet (preferably non-woven fabric) (see FIG. 6). A plurality of fiber lumps contained in the absorbent (absorbent core) of the present invention are a plurality of sheet-like fibers having a higher formability as compared to those produced by the prior art such as

Patent Documents

3 and 4. It is a mass.

It is preferable that 90% by mass or more of the constituent fibers 11F of the fiber mass 11 be synthetic fibers, and it is preferable that 100% by mass, that is, all the constituent fibers 11F be synthetic fibers. Further, as described later, it is more preferable that the constituent fiber 11F which is a synthetic fiber is non-water absorbent.

In the absorbent core 40, a plurality of fiber masses 11 or the fiber masses 11 and the water absorbent fibers 12F are entangled. In the absorbent core 40 of the present embodiment, a plurality of fiber masses 11 are joined by entanglement with constituent fibers (

fibers

11 F and 12 F) in the absorbent core 40 to form one fiber mass continuum. In addition, the plurality of fiber masses 11 may be entangled, and the fiber masses 11 and the water absorbent fibers 12F may be entangled and bonded. Furthermore, usually, the plurality of water absorbent fibers 12F are also entangled with each other. At least a portion of the plurality of fiber masses 11 contained in the absorbent core 40 is entangled with the other fiber masses 11 or the water absorbent fibers 12F. In the absorbent core 40, all of the plurality of fiber masses 11 contained therein may be entangled with each other to form one fiber mass continuum, or the plurality of fiber mass continuums are not mutually It may be mixed in the coupled state.

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

The deformation state when the absorbent core 40 is compressed by receiving the external force F is schematically shown in FIG. 4. In the absorbent core 40 in which the fiber mass 11 which is a fiber aggregate and the water-absorbent fiber 12F which is a non-fiber aggregate are mixed, the boundary between both

members

11 and 12F is caused due to the difference in rigidity between the both

members

11 and 12F. Particularly easy to bend at BL (dotted line in FIG. 24), where the boundary BL functions as a bend at the time of deformation of the absorbent core 40, the boundary BL which is the bend is generally present over the entire area of the absorbent core 40. Therefore, the absorbent core 40 is flexibly deformed in response to various external forces, and when the external force is released, the compression recovery property of the fiber mass 11 can be used to quickly release the original. Can be restored to Such deformation-recovery properties of the absorbent core 40 can be developed not only when the absorbent core 40 is compressed but also when it is twisted. That is, since the absorbent core 40 incorporated in the napkin 1 is disposed in a state of being sandwiched between the thighs of the wearer when the napkin 1 is worn, the absorbent core 40 is a component that the wearer walks The motion of the two thighs during operation may cause it to twist about a virtual axis of rotation extending in the longitudinal direction X, but even in such a case the absorbent core 40 has high deformation-recovery properties Therefore, it can be easily deformed and recovered against an external force that promotes twisting from the both thighs, and therefore, it is difficult to cause the napkin 1 to have a high fit to the wearer's body.

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

Thus, in the absorbent core 40, as in the form A, the fiber mass 11 is bonded to the other fiber mass 11 or the water-absorbent fibers 12F by entanglement or “interlacing” of the fibers with each other, and the form Like B, they are also present in a state in which they can be entangled with other fiber masses 11 or water-absorbent fibers 12F, and such entanglement of fibers causes the above-described effects of the absorbent core 40 to be more effectively exhibited. It has become one of the important points. However, the absorbent core 40 preferably has the “confounding” of Form A from the viewpoint of shape retention. Bonding by entanglement of fibers is not by adhesion or fusion using an adhesive component, but by only entanglement of fibers, so compared to bonding by “fusion of fibers” as described in Patent Document 3, for example. , The degree of freedom of movement of the individual elements (fiber mass 11, water absorbent fibers 12F) which are entangled is high, so that the individual elements move within a range that can maintain the integrity as an assembly of them. obtain. As described above, the absorbent core 40 has a plurality of fiber masses 11 contained in each other or the fiber mass 11 and the water-absorbent fibers 12F which are relatively loosely bonded to each other, so that they are deformed when receiving an external force. Possible shape retention is moderate, and shape retention and cushioning properties, compression recovery, etc. are compatible at a high level.

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

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

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

One of the main features of the absorbent core 40 is the outer shape of the fiber mass 11. Two typical external shapes of the fiber mass 11 are shown in FIG. More specifically, the fiber mass 11A shown in FIG. 5A has a rectangular parallelepiped shape, and the fiber mass 11B shown in FIG. 5B has a disk shape. The

fiber mass

11A, 11B is common in that it includes two opposing base planes 111 and a body plane 112 connecting the two basic planes 111. Each of the basic surface 111 and the skeletal surface 112 is a portion which is recognized to be substantially non-uniform at a level applied when evaluating the degree of surface irregularity in an article mainly composed of this type of fiber.

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

fiber masses

11A and 11B are also common in that the skeletal surface 112 has a rectangular shape, more specifically, a rectangular shape in plan view.

The plurality of fiber masses 11 contained in the absorbent core 40 each have two opposing basic surfaces 111 and a skeletal surface 112 connecting the two basic surfaces 111, such as the

fiber masses

11A and 11B shown in FIG. It differs from the non-woven fabric pieces or fine webs described in

Patent Documents

3 and 4 which are indeterminate shaped fiber aggregates in that they are "formed fiber aggregates". In other words, when any one fiber mass 11 in the absorbent core 40 is seen through (for example, when observed with an electron microscope), the see-through shape of the fiber mass 11 differs depending on the observation angle, and one fiber Where there are multiple fluoroscopic shapes per mass 11, each of the plurality of fiber masses 11 in the absorbent core 40, as one of its multiple fluoroscopic shapes, connects two opposing base surfaces 111 and two base surfaces 111. And a skeletal surface 112 having a specific perspective shape. The plurality of non-woven fabric pieces or fine webs contained in the absorbent bodies described in

Patent Documents

2 and 3 substantially have "surfaces" such as the basic surface 111 and the skeletal surface 112, that is, an enlarged portion. In addition, the external shapes are different from each other and not “fixed”.

As described above,

Patent Documents

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

In the fiber mass 11, the total area of the two basic surfaces 111 is preferably larger than the total area of the skeletal surface 112. That is, in the rectangular parallelepiped fiber mass 11A of FIG. 5A, the sum of the areas of the two basic surfaces 111 is larger than the sum of the areas of the four skeletal surfaces 112, and FIG. In the disk-shaped fiber mass 11B, the sum of the areas of the two basic surfaces 111 is larger than the area of the skeletal surface 112 forming the circumferential surface of the disk-shaped fiber mass 11B. In any of the

fiber masses

11A and 11B, the basic surface 111 is the surface having the largest area among the plurality of surfaces possessed by the

fiber masses

11A and 11B.

Such a fiber mass 11 which is a “shaped fiber aggregate” defined by two basic surfaces 111 and a skeletal surface 112 intersecting both basic surfaces 111 differs from the prior art in the manufacturing method. Can be realized by A preferable method for producing the fiber mass 11 is, as shown in FIG. 6, a cutting means such as a cutter or the like as a raw material fiber sheet 10bs (sheet having the same composition as the fiber mass 11 and having a size larger than the fiber mass 11) It is used to cut into a fixed shape. The fiber masses 11 thus produced are more regular in shape and size compared with those produced by the prior art such as

Patent Documents

3 and 4. FIG. 6 is a view for explaining the method of manufacturing the rectangular parallelepiped fiber mass 11A of FIG. 5A, and the dotted line in FIG. 6 shows a cutting line. In the absorbent core 40, a plurality of fiber masses 11 having uniform shape and size, which are obtained by cutting the fiber sheet into a fixed shape as described above, are blended. As mentioned above, a nonwoven fabric is preferable as the raw fiber sheet 10bs.

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

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

Further, the outer shape of the fiber mass 11 is not limited to that shown in FIG. 5, and both the basic surface 111 and the skeletal surface 112 are flat surfaces which are not curved as in the

respective surfaces

111 and 112 of FIG. Alternatively, it may be a curved surface as in the skeletal surface 112 (the peripheral surface of the disk-shaped fiber mass 11B) in FIG. 5 (b). The basic surface 111 and the skeletal surface 112 may have the same shape and the same size, and specifically, for example, the outer shape of the fiber mass 11A may have a cubic shape.

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

The fiber end portion present on each surface (basic surface 111, skeletal surface 112) of the fiber mass 11 is between the fiber mass 11 and the other fiber masses 11 contained in the absorbent core 40 or the water-absorbent fibers 12F. Useful for forming confounds. In general, the confoundability can be improved as the number of fiber ends per unit area increases, and therefore, various properties such as shape retention of the absorbent core 40 can be improved. And, as described above, the number per unit area of the fiber end on each surface of the fiber mass 11 is not uniform, and the number per unit area of such a fiber end is “skeleton surface 112> basic surface 111”. Since the size relationship is established, the interlacing property with other fibers (the other fiber mass 11, the water absorbent fiber 12F) via the fiber mass 11 differs depending on the surface of the fiber mass 11, and the skeletal surface 112 is the basic surface 111 Confoundability is higher than. That is, the bonding by interlacing with other fibers through the skeletal surface 112 has a stronger bonding force than that through the basic surface 111, and the basic surface 111 and the skeletal surface in one fiber mass 11 At 112, there may be a difference in bonding strength with other fibers.

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

In particular, in the fiber mass 11 (11A, 11B) shown in FIG. 5, as described above, the total area of the two basic surfaces 111 is larger than the total area of the skeletal surface 112. For this reason, the number of the fiber area per unit area is relatively small, and hence the basic surface 111 having relatively low interlacing property with other fibers has the opposite property to the skeletal surface 112. Rather, it means that the total area is large. Therefore, the fiber mass 11 (11A, 11B) shown in FIG. 5 has the other fibers in the periphery (other fiber masses 11, water-absorbent fibers 12F, as compared to the fiber mass in which the fiber end uniformly exists on the entire surface. Entanglement) is easily suppressed, and even if it is entangled with other fibers in the periphery, it is easy to entangle with relatively weak bonding power, and therefore, it is difficult to become large lumps and the softness excellent in the absorbent core 40 It is possible to give sex.

On the other hand, the non-woven fabric pieces or fine webs described in

Patent Documents

3 and 4 are manufactured by, for example, cutting the raw fiber sheet into an irregular shape with a cutter such as a mill cutter as described above. It is not a piece of sheet-like shaped fiber lump having a "face" like the face 111 or the skeletal face 112, and furthermore, the external force of the cutting process is applied to the entire fiber lump at the time of its production. The fiber ends of the above are randomly formed in the entire fiber mass, and it is difficult to sufficiently express the above-mentioned effects by the fiber ends.

From the viewpoint of more reliably achieving the function and effect by the fiber end portion described above, the number N ₁ per unit area of the fiber end portion of the basic surface 111 (non-cut surface) and the skeletal surface 112 (cut surface) The ratio of the fiber end to the number N ₂ per unit area is preferably 0 or more, more preferably 0.05 or more, and preferably 0 as N ₁ / N ₂ on the premise that N ₁ <N _2. Or less, more preferably 0.60 or less. More specifically, N ₁ / N ₂ is preferably 0 or more and 0.90 or less, and more preferably 0.05 or more and 0.60 or more.
The number N ₁ per unit area of the fiber ends of the basic surface 111 is preferably 0 piece / mm ² or more, more preferably 3 pieces / mm ² or more, and preferably 8 pieces / mm ² or less, more preferably It is 6 pieces / mm ² or less.
The number N ₂ per unit area of the fiber end of the skeletal surface 112 is preferably 5 pieces / mm ² or more, more preferably 8 pieces / mm ² or more, and preferably 50 pieces / mm ² or less, more preferably It is 40 pieces / mm ² or less.
The number per unit area of the fiber end of the basic surface 111 and the skeletal surface 112 is measured by the following method.

<Method of measuring the number of fiber ends per unit area on each surface of a fiber mass>
Using a paper double-sided adhesive tape (Niistack NW-15 manufactured by Nichiban Co., Ltd.), a measurement piece is stuck on a sample table using a member (fiber mass) containing fibers to be measured. The measurement piece is then coated with platinum. The coating is performed using an ion sputtering apparatus E-1030 (trade name) manufactured by Hitachi Naka Seiki Co., Ltd., and the sputtering time is 120 seconds. The cut surface of the measurement piece is observed at a magnification of 100 times the basic surface and the skeletal surface using a JCM-6000 type electron microscope manufactured by JEOL. In this observation screen with a magnification of 100 times, a rectangular area of 1.2 mm long and 0.6 mm wide is set at an arbitrary position on the measurement target surface (basic surface or skeletal surface), and the area of the rectangular region is After adjusting the observation angle and the like to occupy 90% or more of the area of the observation screen, the number of fiber ends included in the rectangular area is measured. However, in the observation screen with a magnification of 100 times, in the case where the measurement target surface of the fiber mass is smaller than 1.2 mm × 0.6 mm and the ratio of the area of the rectangular region to the entire observation screen is less than 90%. After increasing the observation magnification to 100 times, the number of fiber ends included in the rectangular area in the measurement target surface is measured in the same manner as described above. Here, the “fiber end” to be subjected to the number measurement is the end in the lengthwise direction of the constituent fibers of the fiber mass, and the portion other than the end in the lengthwise direction of the constituent fiber from the surface to be measured Even if the part) is extended, the longitudinal middle part is not targeted for the number measurement. And the number per unit area of the fiber end in the measurement object surface (basic surface or frame surface) of a fiber lump is computed by a following formula. For each of the ten fiber masses, the number per unit area of the fiber end in each of the base surface and the skeletal surface is measured according to the above procedure, and the average value of the plurality of measured values is calculated as the fiber end in the measurement target surface. The number per unit area of
Number of fiber ends per unit area in the measurement target surface (basic surface or skeletal surface) of the fiber mass (number / mm ² ) = number of fiber ends included in rectangular area (1.2 × 0.6 mm) Area of the rectangular area (0.72 mm ² )

When the basic surface 111 of the fiber mass 11 has a rectangular shape in plan view as in the fiber mass 11A shown in FIG. 5A, the viewpoint of the improvement of the uniform dispersion of the fiber mass 11 in the absorbent core 40 Therefore, the short side 111a of the rectangle is preferably shorter than the thickness of the absorbent core 40 containing the fiber mass 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, and preferably 1 or less, more preferably 0.5 as the former / the latter. It is below.
The thickness of the absorbent core 40 is preferably 1 mm or more, more preferably 2 mm or more, and preferably 10 mm or less, more preferably 6 mm or less. The thickness of the absorbent core 40 is measured by the following method.

<Method of measuring thickness of absorbent (absorbent core)>
Place the object to be measured (absorber, absorbent core) in a horizontal place without wrinkles or bending, and measure the thickness of the object under a load of 5 cN / cm ² . Specifically, for measurement of thickness, for example, a thickness gauge PEACOCK DIAL UPRIGHT GAUGES R5-C (manufactured by OZAKI MFG. CO. LTD.) Is used. At this time, between the tip of the thickness meter and the object to be measured, the plate is circular or square in plan view, the size of which is adjusted so that the load on the object to be measured is 5 cN / cm ² Place an acrylic plate of about 5 mm and measure the thickness. The thickness is measured at 10 points, and their average value is calculated to be the thickness of the object to be measured.

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

Further, it is preferable that in the absorbent core 40, the fiber mass 11 be distributed at high density and uniformly all over the absorbent core 40, since responsiveness to external force tends to be isotropic. From such a point of view, in the projection view of the absorbent core 40 in two directions orthogonal to each other, it is preferable that an overlapping portion of the plurality of fiber masses 11 exist in an arbitrary 10 mm square unit area. The code | symbol 11Z in FIG.3 and FIG.4 has shown the overlapping part of the some fiber mass 11. In FIG. Here, as “projection in two directions orthogonal to each other”, typically, projection in the thickness direction of the absorbent core (that is, when the absorbent core is observed from the skin facing surface or the non-skin facing surface) And a projection view in a direction orthogonal to the thickness direction (ie, when the absorbent core is observed from the side).

FIG. 7 (a) shows an electron micrograph of an example of the fiber mass according to the present invention, and FIG. 7 (b) shows a schematic view of the fiber mass 11 in accordance with the electron micrograph. It is done. As shown in FIG. 7, the plurality of fiber masses 11 included in the absorbent core 40 includes a main body portion 110 and fibers 11 F extending outward from the main body portion 110, and the main body portion 110. And fibers having a low fiber density (the number of fibers per unit area is small) and an extended fiber portion 113 can be included. The absorbent core 40 may include the fiber mass 11 having no extension fiber portion 113, that is, the fiber mass 11 formed only of the main body portion 110. The extended fiber portion 113 may include one of the fiber ends existing on each surface (the base surface 111 and the skeletal surface 112) of the fiber mass 11 as described above, and it is a fiber among the fiber ends. It is a fiber end extending outward from each surface of the mass 11.

The main body portion 110 is a portion defined by the two opposing basic surfaces 111 described above and a skeletal surface 112 connecting the two basic surfaces 111. The main body portion 110 is a main body of the fiber mass 11 and is a portion that forms a fixed outer shape of the fiber mass 11, and various characteristics such as high flexibility, cushioning property, and compression recovery property of the fiber mass 11 are basically However, the location of the main body 110 is large. On the other hand, the extension fiber portion 113 mainly contributes to the improvement of the interlacing property between the plurality of fiber masses 11 contained in the absorbent core 40 or between the fiber mass 11 and the water absorbent fibers 12F, and the retention of the absorbent core 40 In addition to directly contributing to the improvement of the formability, it may indirectly reinforce the action and effect due to the main body portion 110 by also affecting the uniform dispersibility of the fiber mass 11 in the absorbent core 40 and the like.

The main body portion 110 has a higher fiber density than the extension fiber portion 113, that is, the number of fibers per unit area is large. Also, usually, the fiber density of the main body 110 itself is uniform. The proportion of the main body portion 110 in the total mass of the fiber mass 11 is usually at least 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 85% by mass or more. The main body portion 110 and the extension fiber portion 113 can be distinguished by the following specific operation of the outer shape.

The task of specifying the external shape of the main body portion 110 of the fiber mass 11 contained in the absorbent core 40 is the height difference of the fiber density in the fiber mass 11 and its peripheral portion (more or less of the number of fibers per unit area) This can be performed by confirming the “boundary” between the main body portion 110 and the other portion, paying attention to the type of fiber, the difference in fiber diameter, and the like. The main body portion 110 has a fiber density higher than that of the extension fiber portion 113 present around the main body portion 110, and usually, the synthetic fiber which is a constituent fiber of the main body portion 110 is a water absorbing fiber 12F (typically a cellulose fiber) Since the qualitative and / or dimensionally different ones, even in the absorbent core 40 in which a large number of fiber lumps 11 and water absorbent fibers 12 F are mixed, the boundary can be easily confirmed by paying attention to the above point. The boundary thus confirmed is the peripheral edge (side) of the basic surface 111 or the skeletal surface 112, and the boundary confirmation operation identifies the basic surface 111 and the skeletal surface 112, and thus the main body 110 is specified. Be done. Such boundary confirmation operation can be performed by observing the object (the absorbent core 40) at a plurality of observation angles as necessary using an electron microscope. In particular, the fiber mass 11 contained in the absorbent core 40 is such that “the total area of the two basic surfaces 111 is larger than the total area of the skeletal surface 112” such as the

fiber masses

11A and 11B shown in FIG. In the case where the basic surface 111 is the surface having the largest area of the fiber mass 11, it is possible to relatively easily identify the large surface of the basic surface 111, The external shape can be specified smoothly.

As shown in FIG. 7, the extension fiber portion 113 extends outward from at least one of the basic surface 111 and the skeletal surface 112 forming the outer surface of the main portion 110, and is a component fiber of the main portion 110. It consists of 11F. FIG. 7 is a plan view of the fiber mass 11 viewed from the basic surface 111 side (surface having the largest area among the plurality of surfaces of the fiber mass 11), and the fibers 11F from the skeletal surface 112 intersecting the basic surface 111 are shown. A plurality of extended fiber portions 113 are formed.

The form of the extension fiber portion 113 is not particularly limited. The extension fiber part 113 may be comprised from one fiber 11F, and may be comprised from the some fiber 11F like the extension fiber bundle part 113S mentioned later. In addition, although the extension fiber portion 113 includes the longitudinal direction end portion of the fiber 11F extending from the main body portion 110, in addition to such a fiber end portion or in place of the fiber end portion, the length of the fiber 11F There may be cases where it may include portions other than the direction end portions (longitudinal middle portions). That is, in the fiber mass 11, both ends in the longitudinal direction of the constituent fiber 11F exist in the main body 110, and the other parts, that is, the longitudinal intermediate portions extend outward from the main body 110 in a loop Where there is a possibility of protrusion, the extension fiber portion 113 in that case is configured to include a loop-like protrusion of such a fiber 11F. In other words, in the extended fiber portion 113, the one whose end is exposed is one of the fiber ends.

One of the main roles of the extended fiber portion 113 is, as described above, to entangle the plurality of fiber masses 11 contained in the absorbent core 40 with each other, or the fiber mass 11 and the water absorbent fibers 12F. . Generally, the extension length from the main body part 110 of the extension fiber part 113 becomes long, or the thickness of the extension fiber part 113 becomes thick, or the number of the extension fiber parts 113 which one fiber mass 11 has When the amount of entanglement increases, the connection between the objects being entangled via the extension fiber portion 113 becomes strong and it becomes difficult to release the entanglement, so that the predetermined effect of the present invention is exhibited more stably. Become.

When the fiber mass 11 is obtained by cutting the raw material fiber sheet 10bs into a fixed shape as shown in FIG. 6, the extended fiber portion 113 is relatively abundant in the skeletal surface 112 which is the cut surface. On the other hand, it does not exist at all in the basic surface 111 which is a non-cut surface, or its number is smaller than that of the skeletal surface 112 even if it exists. As described above, the reason why the extension fiber portion 113 is unevenly distributed on the skeletal surface 112 which is the cut surface is that most of the extension fiber portions 113 are “fluffs” generated by cutting of the raw material fiber sheet. That is, since the skeletal surface 112 formed by cutting the raw fiber sheet 10bs is entirely rubbed by the cutting means such as a cutter at the time of cutting, fuzz made of the constituent fibers 11F of the sheet 10bs is easily formed, so-called fuzzing easy. On the other hand, since the basic surface 111 which is a non-cut surface does not have friction with such a cutting means, it is difficult to form the fuzz or the extension fiber part 113.

The spacing L1a (the spacing in the first direction) and the spacing L2a (the spacing in the second direction) of the cutting line at the time of cutting the raw fiber sheet 10bs are the viewpoints such as the formation promotion of the extending fiber portion 113 described above From the viewpoint of securing the dimensions necessary for achieving a predetermined effect, it is preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 30 mm or less, more preferably 15 mm or less.

As shown in FIG. 7, the fiber mass 11 is an extension fiber bundle portion including a plurality of fibers 11F extending outward from the main body portion 110, more specifically, the skeletal surface 112, as one type of the extension fiber portion 113. It has 113S. At least one of the extension fiber portions 113 included in the fiber mass 11 may be this extension fiber bundle portion 113S. The extended fiber bundle portion 113S is configured by gathering together a plurality of fibers 11F extending from the skeletal surface 112, and extends from the main body portion 110 (the skeletal surface 112) compared to the extended fiber portion 113. It is characterized by the fact that the output length is long. The extended fiber bundle portion 113S may be present also on the basic surface 111, but is typically present on the skeletal surface 112 as shown in FIG. 7 and may or may not be present on the basic surface 111 at all. The number is fewer than the skeletal surface 112. The reason is the same as the reason why the extension fiber portion 113 mainly exists in the skeletal surface 112 which is the cut surface, as described above.

Since the fiber mass 11 has such an extended fiber bundle portion 113S which should be also referred to as a long and thick large-sized extended fiber portion 113, the fiber mass 11 or the fiber mass 11 and the water absorbing fiber 12F Confounding is further intensified, and as a result, the predetermined effect of the present invention due to the presence of the fiber mass 11 is more stably exhibited. The extended fiber bundle portion 113S can be easily formed by performing the above-described cutting of the raw material fiber sheet 10bs under the condition of being easily fuzzed (see FIG. 6).

The extension length of the extension fiber bundle portion 113S from the main body portion 110, that is, the extension length from the skeletal surface 112 (cut surface) is preferably 0.2 mm or more, more preferably 0.5 mm or more, and Preferably it is 7 mm or less, More preferably, it is 4 mm or less. The extension length of the extension fiber bundle portion 113S can be measured in the identification operation (boundary confirmation operation) of the outer shape of the fiber mass 11 described above. Specifically, for example, using a microscope (50 magnification) made of Keyence, a double-sided tape made by 3M Co., Ltd. was attached to the surface of a transparent sample stand made of acrylic, and the fiber mass 11 was placed thereon and fixed Above, after identifying the outer shape of the fiber mass 11 according to the specific operation of the outer shape described above, the length of the extension in the fiber 11F extended from the outer shape is measured, and the measured extension The length of the portion is taken as the extension length of the extension fiber bundle portion 113S.

In the extended fiber bundle portion 113S, it is preferable that the plurality of constituent fibers 11F be thermally fused to each other. The heat-sealed portion of such an extended fiber bundle portion 113S is generally in the longitudinal direction of the extended fiber bundle portion 113S as compared with the other portion (non-heat-sealed portion) of the extended fiber bundle portion 113S. The crosswise length (in the case where the cross section of the heat-sealed portion is circular, the diameter) is long in the direction orthogonal to Since the extension fiber bundle portion 113S has a heat-sealed portion that can be said to be such a large diameter portion, the strength of the extension fiber bundle portion 113S itself is enhanced, and thereby, via the extension fiber bundle portion 113S. The entanglement between the fiber masses 11 which are entangled with each other or the fiber mass 11 and the water absorbent fibers 12F is further strengthened. Further, when the extension fiber bundle portion 113S has a heat fusion bonding portion, not only when the extension fiber bundle portion 113S is in a dry state but also when it is in a wet state by absorbing water, There is an advantage that the strength, shape retention property, and the like of the extended fiber bundle portion 113S itself are enhanced. And by such merits, when the absorbent core 40 is applied to the napkin 1, not only when the absorbent core 40 is in a dry state, but also the body fluid such as urine and menstrual blood excreted by the wearer is absorbed. Even in the wet state, the effects due to the presence of the fiber mass 11 described above can be stably exhibited. Such an extension fiber bundle portion 113S having a heat fusion bonding portion is used as a raw material fiber sheet 10bs in the manufacturing process of the fiber mass 11 as shown in FIG. 6, that is, the cutting process of the raw material fiber sheet 10bs of the fiber mass 11. It can be manufactured by using the above-mentioned "fiber sheet having a heat-sealed portion between constituent fibers".

As described above, the fiber mass 11 is characterized in that it has the main body portion 110 (a fiber aggregate of a fixed shape) defined by the basic surface 111 and the skeletal surface 112, and in addition to its constituent fibers 11F. It is also characterized in that it is a synthetic fiber containing a hydrophilizing agent. The "hydrophilizing agent" referred to in the present invention improves the hydrophilicity of the fiber when the hydrophilizing agent is applied to the fiber, more specifically, the contact angle with water measured by the following method It is an agent to reduce.

Whether the fiber is hydrophilic or hydrophobic can be judged based on the contact angle with water measured by the following method, and if it is less than 90 degrees, it is hydrophilic, if it is 90 degrees or more It is hydrophobic. The smaller the contact angle with water measured by the following method, the higher the hydrophilicity (the lower the hydrophobicity), and the larger the contact angle, the lower the hydrophilicity (a higher hydrophobicity).

<Method of measuring contact angle>
The fiber is taken out of the object to be measured (absorbent core), and the contact angle of water to the fiber is measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Deionized water is used to measure the contact angle. The amount of liquid discharged from an inkjet type water droplet discharge part (manufactured by Cluster Technology, pulse injector CTC-25 with a discharge hole diameter of 25 μm) is set to 20 picoliter, and a water droplet is dropped right above the fiber. The state of dropping is recorded on a high-speed recording device connected to a camera installed horizontally. From the viewpoint of later image analysis, the recording device is preferably a personal computer in which a high-speed capture device is incorporated. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of a drop of water on the fiber, attached software FAMAS (version of software is 2.6.2, analysis method is the drop method, analysis method is the θ / 2 method, image processing algorithm Image analysis is performed with no reflection, image processing image mode is frame, threshold level is 200, curvature correction is not performed, and the angle between the surface of the water droplet that touches the air and the fiber is calculated. Be a corner. The fiber removed from the object to be measured is cut into a fiber length of 1 mm, and the fiber is placed on the sample table of the contact angle meter and kept horizontal. Two different contact angles are measured per fiber. A contact angle of N = 5 is measured to one decimal place, and a value obtained by averaging a total of ten measured values (rounded to the second decimal place) is defined as the contact angle of the fiber with water. The measurement environment is room temperature 22 ± 2 ° C. and humidity 65 ± 2% RH.

In addition, when the absorber (absorbent core) of measurement object is used as a component of other articles | goods, such as an absorbent article, and this absorber is taken out and evaluated and measured, this absorber is an adhesive agent, If it is fixed to another component by fusion bonding etc., remove the adhesive force by a method such as blowing cold air of the cold spray within the range that does not affect the contact angle of the fiber. Take it out of This procedure is common to all measurements herein.

The fact that the synthetic fiber that is the component fiber 11F of the fiber mass 11 contains a hydrophilizing agent means that the fiber mass 11 is subjected to a hydrophilization treatment. As one of the effects of the hydrophilization treatment of the fiber mass 11 contained in the absorbent core 40, physical properties in the case where the absorbent core 40 is in a wet state by absorbing and holding the liquid Improvement is mentioned. According to the findings of the present inventor, when the degree of hydrophilization of the constituent fibers (synthetic fibers) of the fiber mass is increased (the contact angle with water is reduced), compression in the wet state of the absorbent core containing it is achieved. The amount of work (w-WC) tends to increase. Since the increase in the value of w-WC leads to an improvement in the cushioning properties of the absorbent core in the wet state, it is possible to include the hydrophilizing agent in the constituent fibers (synthetic fibers) of the fiber mass in the wet state of the absorbent core. It is effective to improve the cushioning properties of

Further, in the absorbent core 40, as described above, the fiber mass 11 and the water-absorbent fiber 12F which are the constituent members thereof are mutually joined by confounding between the same kind and between the different kinds, and due to this, they are fused by fusion. Where the mobility of the body fluid (liquid diffusivity in the surface direction, liquid permeability in the thickness direction) is potentially enhanced as compared to the bound case, the fiber mass 11 is further hydrophilized In addition, the excellent properties involved in the movement of these body fluids can be further improved. For example, when the absorbent core 40 initially receives the body fluid of the wearer of the napkin 1 at the excretory part facing portion located at the central portion of the longitudinal central area B in the skin facing surface, the body fluid is subjected to a hydrophilization treatment The composite fiber 11F of the fiber mass 11, that is, the synthetic fiber containing the hydrophilizing agent, and the water absorbing fiber 12F to be entangled therewith are rapidly drawn into the interior of the absorbent core 40 from the excretory part facing portion, and further Can diffuse rapidly in the thickness direction toward the non-skin facing surface side (rear sheet 3 side) while diffusing in the surface direction in the absorbent core 40 quickly.

In addition, as described above, the fiber mass 11 has the main body portion 110 defined by the basic surface 111 and the skeletal surface 112. In these

surfaces

111 and 112, inter-fiber gaps of the constituent fibers 11F are generally used. There are many. When the fiber mass 11 having a large number of interfiber spaces on the surface is subjected to hydrophilization treatment, the body fluid existing outside the fiber mass 11 (body portion 110) is treated as a fiber mass 11 by the capillary action of the interfiber space. Can be drawn into the interior of the body, and as a result, the liquid absorbability of the absorbent core 40 can be improved.

Further, as described above, the fiber mass 11 includes the extension fiber portion 113 extending outward from the main body portion 110, and the extension fiber portion 113 includes a plurality of fibers 11F extending from the main body portion 110. Where the contained fiber bundle portion 113S may be present, if the fiber 11F contains a hydrophilizing agent, the fiber bundle portion 113S naturally contains a hydrophilizing agent, whereby the degree of hydrophilicity is enhanced. As a result, the movement of the body fluid via the extension fiber bundle portion 113S can be made smoother. That is, by the constituent fibers 11F of the fiber mass 11 containing a hydrophilizing agent, in addition to the effect of improving the entanglement strength between the fiber masses 11 or the fiber mass 11 and the water absorbent fibers 12F, further in the absorbent core 40 The effect of improving the mobility of body fluid can also be expected, and even when an external force is applied due to the body pressure of the wearer of the napkin 1 on the absorbent core 40, the body fluid is rapidly transferred in the absorbent core 40. obtain.

A fiber containing a hydrophilizing agent from the viewpoint of more reliably achieving the above-described function and effect due to the synthetic fiber as the constituent fiber 11F of the fiber mass 11 containing the hydrophilizing agent. 11F is preferably a hydrophilic fiber, and the contact angle of fiber 11F (synthetic fiber) with water is preferably 75 degrees or less, more preferably 70 degrees or less, more preferably 60 degrees or less, particularly preferably 50 degrees It is below. The contact angle of the fiber 11F with water can be adjusted by appropriately adjusting the type and content of the hydrophilizing agent to be contained therein.

The constituent fiber 11F of the fiber mass 11, ie, the synthetic fiber containing a hydrophilizing agent, is produced by adding a hydrophilizing agent to the raw material fiber, and the contact angle of the produced fiber 11F with water is It is reduced than that of the raw fiber. The form of the hydrophilizing agent contained in the fiber 11F is not particularly limited. Typically, the surface layer of the fiber 11F is a hydrophilizing agent, that is, a form in which the hydrophilizing agent adheres to the surface of the raw fiber on a thin film However, instead of this, for example, a hydrophilizing agent may be kneaded into the inside of the raw material fiber, or a hydrophilizing agent may be kneaded into the inside of the raw material fiber, and the hydrophilizing agent may be further added to the surface of the raw material fiber. May be attached.

The hydrophilizing agent used in the present invention is not particularly limited as long as it is a general hydrophilizing agent used for hygiene products. Examples of the hydrophilic agent include those containing an anionic surfactant, a cationic surfactant, an amphoteric surfactant or a nonionic surfactant, and one of these may be used alone or in combination of two or more. be able to. Among these, a hydrophilizing agent containing one or more selected from the group consisting of an anionic surfactant and a nonionic surfactant is preferable because the degree of hydrophilization can be easily controlled. The amount of the hydrophilizing agent applied to the synthetic fiber constituting the fiber mass 11 is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, as the amount of surfactant contained in the hydrophilizing agent. More preferably, it is 0.05% by mass or more, preferably 10% by mass or less, further preferably 5% by mass or less, more preferably 2% by mass or less.

Examples of the anionic surfactant include alkyl sulfates, alkyl sulfonates, alkyl carboxylates and alkyl sulfosuccinates, and anionic surfactants having a sulfonic acid group as a hydrophilic group are particularly preferable.

As said anionic surfactant whose hydrophilic group is sulfonic acid or its salt, a dialkyl sulfonic acid or those salts can be mentioned as a preferable example which shows high permeability by low concentration, for example. Specific examples of the dialkyl sulfonic acid include esterification of a dicarboxylic acid such as dialkyl sulfosuccinic acid and dialkyl sulfoglutaric acid such as dioctadecyl sulfosuccinic acid, didecyl sulfosuccinic acid, ditridecyl sulfosuccinic acid, di 2-ethylhexyl sulfosuccinic acid, and the like; And alpha-sulfonated compounds, 2-sulfotetradecanoic acid 1-ethyl ester (or amide) sodium salt, and 2-sulfohexadecanoic acid 1-ethyl ester (or amide) sodium salt etc. Saturated fatty acids and unsaturated fatty acids Alpha sulfo fatty acid alkyl ester (or amide) in which the α position of ester (or amide) is sulfonated, and dialkyl alkenes obtained by sulfonation of internal olefin of hydrocarbon chain and internal olefin of unsaturated fatty acid And the like can be mentioned acid. The carbon number of each of the two-chain alkyl groups of the dialkylsulfonic acid is preferably 4 or more and 14 or less, and particularly 6 or more and 10 or less. Examples of dialkyl sulfosuccinates include Perex OT-P (product name) manufactured by Kao Corporation.

Examples of the cationic surfactant include alkyl (or alkenyl) trimethyl ammonium halide, dialkyl (or alkenyl) dimethyl ammonium halide, alkyl (or alkenyl) pyridinium halide and the like, and these compounds have 6 or more carbon atoms Those having an alkyl group or alkenyl group of 18 or less are preferred. Examples of the halogen in the halide compound include chlorine, bromine and the like.

Examples of the amphoteric surfactant include alkyl (1 to 30 carbon atoms) dimethyl betaine, alkyl (1 to 30 carbon atoms) amidoalkyl (1 to 4 carbon atoms) dimethyl betaine, alkyl (1 to 30 carbon atoms) dihydroxy Betaine-type amphoteric surfactants such as alkyl (C1-C30) betaines and sulfobetaine-type amphoteric surfactants, alanine-type [alkyl (C1-C30) aminopropionic acid types, alkyl (C1-C30) 30) iminodipropionic acid type] amphoteric surfactant, glycine type [alkyl (C 1 to 30) aminoacetic acid type etc. such as alkyl betaine] amino acid type amphoteric surfactant such as amphoteric surfactant, alkyl (carbon number 1 to 30) aminosulfonic acid type amphoteric surfactants such as taurine type.

Examples of the nonionic surfactant include polyhydric alcohol fatty acid esters such as glycerin fatty acid ester, poly (preferably n = 2 to 10) glycerin fatty acid ester, sorbitan fatty acid ester (all preferably have 8 to 8 carbon atoms of fatty acid) 60), an alkylene oxide adduct of the polyhydric alcohol fatty acid ester (preferably with an added mole number of 2 to 60 moles), a polyoxyalkylene (with an added mole number of 2 to 60) alkyl (with 8 to 22 carbon atoms) amide, polyoxyalkylene (Addition number of moles: 2 to 60) Alkyl (C8 to C22) ether, polyoxyalkylene modified silicone, amino modified silicone and the like can be mentioned.

As a raw material fiber of constituent fiber 11F of fiber mass 11, that is, a synthetic fiber not containing a hydrophilizing agent, various synthetic fibers used for sanitary goods can be used without particular limitation, but preferably thermoplastic It is a fiber. The reason why thermoplastic fibers are preferable as the fibers 11F is that the fiber mass 11 is given a three-dimensional structure in which a plurality of thermoplastic fibers 11F are heat-sealed to one another, and the absorbent core 40 is in either a dry state or a wet state. However, the purpose is to be able to exhibit excellent effects in shape retention, flexibility, cushioning, compression recovery, stiffness and the like. Further, as described above, although it is preferable that the extension fiber bundle portion 113S has a heat fusion bonding portion, the component fiber 11F of the fiber mass 11 is a thermoplastic fiber, such an extension fiber bundle portion It is also possible to obtain the preferred form of 113S. In order to obtain a fiber mass 11 in which a plurality of heat fusion bonding portions are three-dimensionally dispersed, the raw material fiber sheet 10bs (see FIG. 6) may be configured in the same manner. As described above, the raw material fiber sheet 10bs in which the fusion-bonded portion is dispersed three-dimensionally can be manufactured by applying heat treatment such as hot air treatment to the web or nonwoven fabric mainly composed of thermoplastic fibers.

Further, as described above, the constituent fiber 11F constituting the fiber mass 11 is hydrophilic such that the contact angle with water is preferably 75 degrees or less, but it is non-water-absorptive, that is, water (urine, menstrual blood, etc. It is preferable to have the property of hardly absorbing the This is in marked contrast to the fact that the water-absorbent fibers 12F used in combination with the fiber mass 11 have literally water absorption. Not only when the absorbent core 40 is in a dry state but also when it is in a wet state by absorbing the body fluid because the fiber 11F is a non-water-absorbent fiber with poor water absorption, The resulting effects (stability, flexibility, cushioning properties, compression recovery, improvement in stiffness, etc.) are stably exhibited. Therefore, the raw material fiber is preferably a non-water absorbing synthetic fiber.

As used herein, the term "absorbent" is readily understood by those skilled in the art, for example, as pulp is said to be absorbent. Similarly, it can be readily understood that thermoplastic fibers are non-bibulous. On the other hand, the degree of water absorbency of fibers such as synthetic fibers can also be determined by the value of moisture content measured by the following method. As the water-absorbent fiber, the moisture content is preferably 6% or more, and more preferably 10% or more. On the other hand, the non-water absorbent fiber preferably has a moisture content of less than 6%, more preferably less than 4%. When the moisture content is less than 6.0%, the fiber is determined to be a non-water absorbing fiber, and when it is 6.0% or more, the fiber is determined to be a water absorbing fiber.

<Measuring method of moisture content>
The moisture content was calculated by applying the moisture content test method of JIS P 8203 correspondingly. That is, the fiber sample was allowed to stand in a test room with a temperature of 40 ° C. and a relative humidity of 80% RH for 24 hours, and then the weight W (g) of the fiber sample before absolute drying was measured in the room. Thereafter, the fiber sample was allowed to stand for 1 hour in an electric drier (for example, manufactured by Isuzu Seisakusho Co., Ltd.) at a temperature of 105 ± 2 ° C. to carry out a bone-drying treatment of the fiber sample. After drying, Si silica gel (e.g., silica gel) is covered with a fiber sample with Saran wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd. in a test room with a temperature of 20 ± 2 ° C and a relative temperature of 65 ± 2%. Place Toyoda Kako Co., Ltd. in a glass desig- eter (for example, manufactured by Tech Jam Co., Ltd.), and allow the fiber sample to stand until the temperature reaches 20 ± 2 ° C. Thereafter, the constant weight W '(g) of the fiber sample is weighed, and the moisture content of the fiber sample is determined by the following equation. Moisture content (%) = (W-W '/ W') x 100

As a raw material fiber of the component fiber 11F of the fiber lump 11, as mentioned above, the synthetic fiber which uses a thermoplastic and non-water absorbing synthetic resin as a raw material is preferable. As such preferable synthetic resins (thermoplastic resins), for example, polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, polymethacrylic acid alkyl ester, polychlorinated Examples thereof include vinyl and polyvinylidene chloride, and these can be used alone or in combination of two or more. The fiber 11F may be a single fiber composed of one kind of synthetic resin (thermoplastic resin) or a blend polymer in which two or more kinds of synthetic resins are mixed, or may be a composite fiber. The composite fiber here is a synthetic fiber (thermoplastic fiber) obtained by combining two or more types of synthetic resins having different components with a spinneret and simultaneously spinning them, and a plurality of components are continuous in the longitudinal direction of the fiber. In a single fiber, which has the same structure. The form of the composite fiber includes a core-sheath type, a side-by-side type, and the like, and is not particularly limited.

The content of the hydrophilizing agent in the fiber 11F is not particularly limited as long as it is appropriately adjusted according to the type of raw material fiber and hydrophilizing agent, the desired degree of hydrophilization, etc. For example, the thermoplastic resin The total mass of the fiber 11F is used when the material used is as the material and the general agent used as a hydrophilizing agent is used and the contact angle of the fiber 11F with water is 75 degrees or less Preferably it is 0.2 mass% or more, More preferably, it is 0.4 mass% or more, Preferably it is 2.0 mass% or less, More preferably, it is 1.5 mass% or less. If the content of the hydrophilizing agent is too small, the degree of hydrophilization of the fiber mass 11 may be lowered and the above-described effects may not be sufficiently exhibited. Conversely, if the content is too large, the raw material at the production site of the fiber mass 11 Line contamination may occur during transport of the fiber sheet.

On the other hand, as the water-absorbent fibers 12F used in combination with the fiber mass 11, hydrophilic and water-absorbent fibers conventionally used as a material for forming the absorbent core of this kind of absorbent article can be used, for example, Wood pulp such as softwood pulp and hardwood pulp, natural fiber such as non-wood pulp such as cotton pulp and hemp pulp; modified pulp such as cationized pulp and mercerized pulp; regenerated fiber such as cupra and rayon; These can be used alone or in combination of two or more.

The contact angle of the component fibers 11F (synthetic fibers 11F) of the fiber mass 11 with water is preferably equal to or greater than the contact angle of the water absorbent fibers 12F with water. That is, it is preferable that the degree of hydrophilicity of the synthetic fiber 11F is equal to the degree of hydrophilicity of the water absorbent fiber 12F or lower than the degree of hydrophilicity of the water absorbent fiber 12F. By establishing the magnitude relationship of the degree of hydrophilicity, the movement of the body fluid from the fiber mass 11 to the water absorbing fiber 12F or in the opposite direction to this becomes more smoothly performed, and the liquid absorbing property of the absorbent core 40 Further improvement can be expected. As described above, in order to realize the relationship of “fiber 11FFwater absorbent fiber 12F” with respect to the contact angle with water, the degree of hydrophilization of the fiber 11F by the hydrophilizing agent may be appropriately adjusted. The contact angle of the water-absorbent fiber 12F with water is preferably 60 degrees or less, more preferably 40 degrees or less, on the premise that it is smaller than that of the fibers 11F.

Moreover, it is preferable that the contact angle with water of the constituent fiber 11F (synthetic fiber) of the fiber mass 11 is smaller than the contact angle with water of the top sheet 2. That is, it is preferable that the hydrophilicity of the fibers 11F be higher than the hydrophilicity of the top sheet 2. Due to the establishment of such a relationship of the degree of hydrophilicity, in the napkin 1, the liquid absorbed by the surface sheet 2 is quickly taken into the absorbent core 40, and the liquid in the planar direction inside the absorbent core 40 described above. Due to the diffusion effect, the amount of liquid held by the surface sheet 2 and the absorbent core 40 is reduced particularly at the excretory part opposing part located at the central part of the longitudinal central area B (see FIG. 1) of the napkin 1. Even after liquid absorption, an effect is obtained that the cushioning property of the excretory part opposing part and the vicinity thereof is excellent. Thus, in order to realize the magnitude relationship of “surface sheet 2> fibers 11F (fiber mass 11) ≧ water absorbent fibers 12F” with respect to the contact angle with water, the degree of hydrophilization of the fibers 11F is adjusted In addition to the above, if necessary, the surface sheet 2 may be appropriately adjusted by subjecting it to the same hydrophilization treatment as the fibers 11F.

In the absorbent core 40, the content weight ratio of the fiber mass 11 to the water absorbing fiber 12F is not particularly limited, and the kind of the component fiber 11F (synthetic fiber containing a hydrophilizing agent) of the fiber mass 11 and the water absorbing fiber 12F, etc. The mass ratio of the fiber mass 11 to the water-absorbent fiber 12F is the former (fiber mass 11) / (fiber mass 11) /, from the viewpoint of achieving the predetermined effect of the present invention more reliably. The latter (water absorbent fiber 12F) is preferably 20/80 to 80/20, more preferably 40/60 to 60/40.

The content of the fiber mass 11 in the absorbent core 40 is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 80% by mass or less based on the total mass of the absorbent core 40 in a dry state. More preferably, it is 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 preferably 80% by mass, with respect to the total mass of the absorbent core 40 in a dry state. The content is more preferably 60% by mass or less.

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

As described above, the excellent effects exerted by the absorbent core 40, specifically, for example, cushioning property, compression recovery property, liquid draw-in property, liquid diffusibility, etc. in any state of dry state and wet state The excellent effect is largely attributable to the inclusion of the fiber mass 11 having the fiber 11F containing the hydrophilizing agent as a constituent fiber, and the distribution state of the fiber mass 11 in the absorbent core 40 is based on the absorbent core 40. It may have a considerable influence on the expression of the action and effect.

For example, the side relatively close to the skin of the wearer of the napkin 1 when the absorbent core 40 is bisected in the thickness direction (the direction orthogonal to the skin facing surface or the non-skin facing surface of the absorbent core 40) That is, when the fiber lump 11 is present on the skin facing surface side (surface sheet 2 side) of the absorbent core 40, the fiber lump 11 having a low liquid retention property compared to the water absorbent fiber 12F is near the wearer's skin As a result, the body fluid can be smoothly transferred from the skin facing surface side to the non-skin facing surface side (back sheet 3 side), resulting in improvement of the liquid drawability of the absorbent core 40. Since the liquid residue on the skin facing surface of the top sheet 2 is reduced, the unpleasant wet feeling and the sticky feeling are suppressed, which may lead to the improvement of the wearing feeling of the napkin 1.

In addition, the development of the functional effects (cushioning property, liquid absorbing property, etc.) by the absorbent core 40 is affected not only by the distribution of the fiber mass 11 in the absorbent core 40 but also by the orientation of the fiber mass 11 to some extent. . Basically, the plurality of fiber masses 11 contained in the absorbent core 40 are random with respect to the thickness direction of the absorbent core 40 (direction orthogonal to the skin facing surface or the non-skin facing surface of the absorbent core 40). It is preferable that the orientation is made as the cushioning property, particularly the cushioning property and the compression recovery property in the wet state of the absorbent core 40, can be compatible with a high level of liquid absorption. Here, “the fiber mass 11 is randomly oriented in the thickness direction of the absorbent core 40” means the longitudinal direction of each of the plurality of fiber masses 11 (main body portion 110), that is, the longitudinal direction of the basic surface 111 When attention is paid to the direction (maximum crossing length direction, radial direction), it means that the major axis directions of the plurality of fiber masses 11 contained in the absorbent core 40 are unequal to each other. When the production of the absorbent core 40 is carried out according to a conventional method using a known stacking device equipped with a rotating drum, a plurality of fiber masses 11 contained in the absorbent core 40 is generally the absorbent core 40. It is in a state of being randomly oriented with respect to the thickness direction of.

Further, at least a part of the plurality of fiber masses 11 contained in the absorbent core 40 is oriented so that the major axis direction (longitudinal direction of the basic surface 111) is along the thickness direction of the absorbent core 40. Is preferred. Here, “orientation along the thickness direction” means that the angle between the major axis direction of the fiber mass 11 and the thickness direction of the absorbent core 40 is 45 degrees or less. Thus, when the fiber mass 11 is oriented in the absorbent core 40 so that the long axis direction of the fiber mass 11 is along the thickness direction of the absorbent core 40, the fiber mass 11 is not oriented as such In the case where, for example, the long axis direction of the fiber mass 11 coincides with the direction orthogonal to the thickness direction of the absorbent core 40, that is, the fiber mass 11 is the surface of the absorbent core 40 facing the skin or the surface not facing the skin In particular, the recoverability of the absorbent core 40 in the wet state can be further improved as compared to the case of being oriented along the direction. Preferably 30% by mass or more, more preferably 50% by mass or more of all the fiber masses 11 contained in the absorbent core 40, the long axis direction of such fiber masses 11 is in the thickness direction of the absorbent core 40 It is preferable that the orientation is along.

As described above, the excellent liquid absorption properties (liquid draw-in properties, liquid diffusion properties, etc.) of the absorbent core 40 can be determined by the constituent fibers 11 F present on the surface of the main body portion 110 of the fiber mass 11, ie, the basic surface 111 This is largely due to the inter-fiber space of In this regard, it is preferable that the constituent fibers 11F of the fiber mass 11 be oriented in the plane direction of the base surface 111. With such a configuration, the inter-fiber spaces of a large number of constituent fibers 11F are formed on the basic surface 111 of the fiber mass 11 (main body portion 110), so the liquid absorbability of the absorbent core 40 can be further improved. Here, "the fibers 11F are oriented in the surface direction of the base surface 111" means that the fibers 11F extend in the surface direction of the base surface 111. More preferably, the fibers 11 F extend in the longitudinal direction of the base surface 111. In addition, preferably 30% or more, more preferably 50% or more of the total number of fibers 11F present in the basic surface 111 is preferably oriented in the plane direction (preferably longitudinal direction) of the basic surface 111.

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

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

The absorbent core 40 can be manufactured in the same way as an absorbent core comprising a fiber material of this kind. As described above, as shown in FIG. 6, the fiber mass 11 is a raw material fiber sheet (a sheet having the same composition as the fiber mass 11 and having a size larger than that of the fiber mass 11) as a raw material using a cutting means such as a cutter. Can be manufactured by cutting in two directions crossing each other (orthogonal), and the plurality of fiber masses 11 manufactured in this way are “shaped fiber aggregates” (for example, body portions having uniform shape and size) 110 is a rectangular parallelepiped shape). The absorbent core 40 including the fiber mass 11 and the water absorbing fibers 12F can be manufactured, for example, according to a conventional method using a known fiber stacking device equipped with a rotating drum. Such a fiber-stacking device typically conveys a rotating drum having a recess for accumulation formed on the outer peripheral surface, and the raw material of the absorbent core 40 (fiber mass 11, water-absorbent fiber 12F) to the recess for accumulation. An air flow (vacuum) generated in the flow path by suction from the inside of the rotating drum while rotating the rotating drum around the rotation axis along the circumferential direction of the drum The raw material carried on the air) is accumulated in the accumulation recess. A piled material formed in the accumulation recess by such a stacking process 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 preferably 800 g / m ² or less, more preferably 600 g / m ² or less.

The absorbent core 40 (absorber 4) having the above-described configuration is flexible and has excellent cushioning properties, is also excellent in compression recovery property, deforms with good responsiveness to external force, and promptly releases external force. Return to original condition. The properties of such an absorbent core can be evaluated on the basis of the work of compression (WC) and the rate of compression recovery (RC). The amount of compressive work is a measure of the cushioning property of the absorbent core, and the larger the WC value, the higher the cushioning property. The compression recovery rate is a scale indicating the degree of recovery when the absorbent core is compressed and the compression state is released, and it can be evaluated that the larger the RC value, the higher the compression recovery. In addition, considering the role of the absorbent core 40 to absorb and hold the liquid, the absorbent core 40 has a WC value and an RC value of not only in a dry state but also in a wet state by absorbing body fluid etc. It is preferable to be large. In order for the absorbent core 40 to have such properties in the 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 mass 11, and the synthetic fiber It is further preferred that they are non-bibulous and thermoplastic.

<Method of measuring compression work (WC) and compression recovery rate (RC)>
It is generally known that the amount of compressive work (WC) and the rate of compressive recovery (RC) of the absorbent core 40 can be represented by the values measured by Kato Tech Co., Ltd. KES (Kawabata Evaluation System) (Reference: Standardization and analysis of texture evaluation (2nd edition), author: Akio Kawabata, published on July 10, 1959). Specifically, the compression work amount and the compression recovery rate can be measured using an automated compression testing apparatus KES-FB3-AUTO-A manufactured by Kato Tech Co., Ltd. The measurement procedure is as follows.
A 195 mm × 68 mm sample of square shape in plan view (absorbent without core wrap sheet, ie, absorbent core) is prepared and attached to the test stand of the compression test apparatus. Next, the sample is compressed between steel plates having a circular flat surface of 2 cm ² in area. The compression rate is 0.01 cm / sec, and the maximum compression load is 490.2 mN / cm ² . The recovery process is also measured at the same speed. The amount of work to be compressed (WC) is expressed by the following equation. _Wherein, T m, _{T o} and P, respectively 490.2mN ^/ cm 2 (4.9kPa) thickness under load, 4.902mN ^/ cm 2 (49Pa) thickness under load, and measuring the time of the load (mN / Cm ² ) is shown.
The compression recovery rate (RC) is the ratio of the compression work amount (WC) at the time of compression to the compression recovery work amount (WC ') at the time of returning from the compression state to the original state [WC' / WC] × 100.

The “absorbent core in a dry state” to be measured by the above measurement method is prepared by leaving the absorbent core to be measured for 24 hours under an environment of 23 ° C. and 50 RH% relative humidity. In addition, the "wet absorbent core" to be measured by the above-mentioned measurement method is adjusted as follows. The dry absorbent core is placed horizontally with the skin-facing side facing up, and a cylindrical acrylic plate with a 1-cm diameter injection port on the bottom is superimposed on the skin-facing side of the absorbent core. It was prepared by injecting 5.0 g of defibrillated horse blood from the inlet and maintaining the condition for 1 minute after the injection. The defibrillated horse blood injected into the absorbent core to be measured is a defibrillated horse blood manufactured by Nippon Biotest Co., Ltd. and whose viscosity at a liquid temperature of 25 ° C. is adjusted to 8 cp. The viscosity is a viscosity as measured with a rotor named L / Adp (rotor code 19) at a rotational speed of 30 rpm in a TVB-10M viscometer manufactured by Toki Sangyo Co., Ltd. In addition, when performing the measurement method, in order to prevent wetting of the measurement device, a portion corresponding to the injection point of defibrillated horse blood of the measurement target (absorbent core) and the periphery thereof in the measurement device, Saran wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd. was coated with a piece of Saran wrap (registered trademark) cut into 4 cm × 4 cm.

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

<1> An absorbent body comprising a fiber mass containing a synthetic fiber and a water-absorbent fiber, wherein the plurality of fiber masses or the fiber mass and the water-absorbent fiber are mutually entangled, wherein the fiber mass is An absorbent body comprising: a main body portion defined by two opposing basic surfaces and a skeletal surface intersecting the two basic surfaces, wherein the synthetic fiber contains a hydrophilizing agent.
The absorbent body as described in said <1> whose contact angle with the water of <2> above-mentioned synthetic fiber is 75 degrees or less, preferably 70 degrees or less, more preferably 60 degrees or less, more preferably 50 degrees or less.
The contact angle with the water of the <3> above-mentioned synthetic fiber is an absorber given in the above <1> or <2> which is more than the contact angle with the water of the above-mentioned water absorbent fiber.
<4> The absorbent according to any one of <1> to <3>, wherein the synthetic fiber is a non-water absorbent fiber.
<5> The absorber according to any one of <1> to <4>, wherein a total area of the two basic surfaces is larger than a total area of the skeletal surface.
<6> In any one of <1> to <5>, the number per unit area of the fiber end portion present in each of the basic surface and the skeletal surface is larger in the skeletal surface than in the basic surface. Absorber as described.
<7> The ratio N ₁ / N ₂ between the number N ₁ per unit area of the fiber end of the basic surface and the number N ₂ per unit area of the fiber end of the skeletal surface is 0 or more. The absorber as described in said <6> which is 90 or less, preferably 0.05 or more and 0.60 or more.
<8> The number per unit area of the fiber end portion of the basic surface is 0 piece / mm ² or more and 8 pieces / mm ² or less, preferably 3 pieces / mm ² or more and 6 pieces / mm ² or less The absorber as described in said <6> or <7>.
<9> The number per unit area of the fiber end of the skeletal surface is 5 / mm ² or more and 50 / mm ² or less, preferably 8 / mm ² or more and 40 / mm ² or less The absorber according to any one of the above <6> to <8>.

<10> The fiber mass is configured to include fibers extending outward from the main body portion, and has an extended fiber portion having a lower fiber density than the main body portion, and the fiber mass of the extended fiber portion The absorbent according to any one of <1> to <9>, wherein at least one of them is an extended fiber bundle including a plurality of fibers extending from the main body.
<11> The absorbent body according to any one of <1> to <10>, wherein the main body portion has a rectangular parallelepiped shape.
<12> The absorbent according to any one of <1> to <11>, wherein the plurality of fiber masses contained in the absorbent are randomly oriented in the thickness direction of the absorbent.
<13> The basic surface has a shape elongated in one direction, and at least a part of the plurality of fiber masses included in the absorbent body is such that the longitudinal direction of the basic surface is along the thickness direction of the absorbent body The absorber according to any one of the above <1> to <12>, which is oriented to
<14> The absorbent according to any one of <1> to <13>, wherein the mass ratio of the fiber mass to the water absorbent fiber is 20/80 to 80/20 as the former / the latter.
<15> The absorbent according to any one of <1> to <14>, in which the constituent fibers of the fiber mass are oriented in the plane direction of the basic surface.

<16> The fiber mass is entangled in the absorbent body with another fiber mass or the water absorbent fiber by entanglement, or in a state capable of being entangled with another fiber mass or the water absorbent fiber The absorbent according to any one of the above <1> to <15>.
<17> The total number of the fiber mass bonded by the entanglement and the fiber mass in the entangled state is preferably half or more, more preferably 70%, of the total number of fiber mass in the absorbent. The absorber as described in said <16> which occupies above, More preferably 80% or more.
<18> Preferably 70% or more, more preferably 80% or more of the total number of the fiber mass having a bonding portion with the other fiber mass or the water-absorbent fiber, wherein the bonding portion is formed by interlacing fibers The absorbent according to any one of <1> to <17>, which is
<19> The absorbent according to any one of <1> to <18>, wherein the fiber mass is derived from a non-woven fabric.
<20> The <1> to the above <1>, wherein the hydrophilizing agent comprises one or more selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant. The absorber as described in any one of <19>.
<21> The absorbent according to <20>, wherein the hydrophilizing agent contains an anionic surfactant.
<22> The absorbent according to <21>, wherein the anionic surfactant comprises an alkyl sulfosuccinate

<23> An absorbent article comprising the absorber according to any one of <1> to <22>.
<24> A liquid-permeable surface sheet is provided on one surface side of the absorber, and the fiber mass is present on the side relatively close from the surface sheet side when the absorber is bisected in the thickness direction The absorbent article as described in said <23>.
<25> The absorbent body and a surface sheet disposed on the skin-facing surface side of the absorbent body, wherein the contact angle of the synthetic fiber with water is compared to the contact angle of the surface sheet with water The absorbent article as described in said <23> or <24> which is small and is more than the contact angle with the water of the said water absorbing fiber.

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

[Examples 1 to 5]
An absorbent core was manufactured and used as a sample of the absorber of each example. Specifically, a fiber mass and a water absorbing fiber were used as a fiber material of the absorbent core, and were manufactured according to a conventional method using a known fiber laying device. The production of the fiber mass was carried out by cutting the raw material fiber sheet in the form of a ridge according to FIG.
21 g / m ² basis weight of non-water-absorbent thermoplastic fiber consisting of polyethylene resin fiber and polyethylene terephthalate resin fiber (non-water-absorbent fiber, fiber diameter 1.8 μm) as raw material fiber sheet of fiber mass An air through non-woven fabric (a fiber sheet having a thermally fused portion of constituent fibers) having a thickness of 0.6 mm was used. The constituent fibers of the fiber mass were in the form in which the hydrophilizing agent was attached on the thin film to the surface of the non-water-absorbing thermoplastic fiber as the raw material fiber. In Examples 1 to 4, 0.4% by mass of composition A having the following composition was used as a hydrophilizing agent based on the constituent fiber mass of the fiber mass. In Example 5, Composition A and a commercially available surfactant (Perex OT-P, manufactured by Kao Corporation) were used as the hydrophilizing agent, and the amount of the hydrophilizing agent used was the mass of the constituent fiber mass. On the other hand, the former is 0.4% by mass, and the latter is 0.2% by mass. A softwood bleached kraft pulp (NBKP) with a fiber diameter of 2.2 μm was used as the water absorbing fiber. The fiber mass used for the absorbent core (shaped synthetic fiber aggregate) has a rectangular parallelepiped main body as shown in FIG. 5 (a), the short side 111a of the basic surface 111 is 0.8 mm, and the long side is 111b was 3.9 mm and the thickness T was 0.6 mm. Further, the number per unit area of the fiber end in the basic surface 111 was 3.2 / mm ² , and the number per unit area of the fiber end in the skeletal surface 112 was 19.2 / mm ² . In the absorbent core of each example, the fiber mass was densely and uniformly distributed.

(Composition of Composition A)
・ Alkyl phosphate ester potassium salt (Kao hydroxide neutralization product of gripper 4131 made by Kao Corporation) 25 mass%
・ Dialkyl sulfosuccinate sodium salt (Kao Co., Ltd. Perex OT-P) 10 mass%
・ Alkyl (stearyl) betaine (Kao Co., Ltd. Anthol 86B) 15 mass%
・ Polyoxyethylene (addition number of moles: 2) Stearylamide (Amizole SDE manufactured by Kawaken Fine Chemicals Co., Ltd.) 30 mass%
・ Polyoxyethylene, polyoxypropylene modified silicone (Shin-Etsu Chemical Co., Ltd. X-22-4515) 20 mass%

Comparative Example 1
The absorbent core of a commercially available sanitary napkin (manufactured by Unicharm Co., Ltd., trade name "Tanom Pew Slim 23 cm") was used as the absorbent of Comparative Example 1 as it was. The absorbent core of Comparative Example 1 is a mixture of synthetic fibers and cellulosic fibers (hydrophilic fibers), and does not contain fiber lumps.

Comparative Example 2
As the fiber mass, an irregular-shaped non-woven fabric piece was used, and the absorbent core was subjected to a hot air process to heat-seal the non-woven fabric pieces contained in the absorbent core with one another. An absorbent was produced in the same manner as 5). In the hot air process applied to the above-mentioned absorbent core, a mixed aggregate of nonwoven fabric pieces and pulp fibers (length 210 mm × width 66 mm) is used in an electric dryer (for example, Isuzu Co., Ltd.) at a temperature of 140 ° C. It was left to stand for 30 minutes, and the non-woven fabric pieces were heat-fused to each other. The irregular-shaped nonwoven fabric piece used was manufactured by tearing off the same one as the air-through nonwoven fabric used in the examples in an arbitrary direction, and the crossover length in plan view was about 25 mm. The composition A was used in Comparative Example 2 as a hydrophilizing agent applied to the constituent fibers of the nonwoven fabric piece.

[Performance evaluation]
With respect to the absorbers of the respective Examples and Comparative Examples, the above-mentioned method enables the dry work compression (d-WC), the wet compression work (w-WC), the dry compression recovery rate (d -RC) The compression recovery rate (w-RC) in the wet state was measured respectively. The results are shown in Table 1 below.

As shown in Table 1, the absorbers of the respective examples were treated to be hydrophilized, including synthetic fibers containing a hydrophilizing agent and defined by two basic planes and a skeletal plane intersecting both basic planes. Due to the inclusion of the shaped fiber mass, the amount of compressive work in both the dry state and the wet state is greater than in Comparative Examples 1 and 2 which do not contain such a fiber mass, and the compression recovery is also achieved. The rate also showed high values in both the dry state and the wet state. In particular, in order to obtain an absorbent body having a large compressive work even in a wet state and excellent cushioning property, in addition to the hydrophilization treatment of the fiber mass in the absorbent body, in particular, in comparison with each Example and Comparative Example 2. It can be seen that it is effective to make the fiber mass in shape and to combine the fiber masses by entanglement.

The absorber of the present invention is excellent in cushioning property and compression recovery property, can be flexibly deformed responsive to external force, and can improve the wearing feeling when applied to the absorbent article. In addition, the absorber of the present invention can exhibit such excellent effects not only before liquid absorption but also in a wet state where the liquid is absorbed and held.
Moreover, since the absorbent article of this invention comprises such a high quality absorber, it is excellent in a wearing feeling and leakproofness.

Claims

An absorbent body comprising a fiber mass containing a synthetic fiber and a water absorbent fiber, wherein a plurality of the fiber masses or the fiber mass and the water absorbent fiber are entangled with each other,
The fiber mass has a main body defined by two opposing base surfaces and a skeletal surface intersecting the two base surfaces,
The absorber which the said synthetic fiber contains the hydrophilizing agent.
The absorbent according to claim 1, wherein the contact angle of the synthetic fiber with water is 75 degrees or less.
The absorbent body according to claim 1 or 2, wherein a contact angle of the synthetic fiber with water is equal to or more than a contact angle of the water absorbent fiber with water.
The absorbent according to any one of claims 1 to 3, wherein the synthetic fiber is a non-water absorbent fiber.
The absorbent according to any one of claims 1 to 4, wherein the total area of the two basic surfaces is larger than the total area of the skeletal surface.
The absorbent according to any one of claims 1 to 5, wherein the number of fiber ends per unit area present in each of the basic surface and the skeletal surface is larger in the skeletal surface than in the basic surface.
The ratio N 1 / N 2 of the number N 1 per unit area of the fiber end of the basic surface to the number N 2 per unit area of the fiber end of the skeletal surface is 0 or more and 0.90 or less The absorber according to claim 6, which is
The absorbent body according to claim 6 or 7, wherein the number per unit area of the fiber end of the basic surface is 0 piece / mm 2 or more and 8 piece / mm 2 or less.
9. The absorbent according to any one of claims 6 to 8, wherein the number per unit area of the fiber end of the skeletal surface is 5 / mm 2 or more and 50 / mm 2 or less.
The fiber mass includes fibers extending outward from the main body portion, and has an extended fiber portion having a lower fiber density than the main body portion.
The absorbent according to any one of claims 1 to 9, wherein at least one of the extension fiber portions is an extension fiber bundle portion including a plurality of fibers extending from the main body portion.
The absorbent according to any one of claims 1 to 10, wherein the main body portion has a rectangular parallelepiped shape.
The absorbent according to any one of claims 1 to 11, wherein the plurality of fiber masses contained in the absorbent are randomly oriented in the thickness direction of the absorbent.
The basic surface has a shape elongated in one direction, and at least a portion of the plurality of fiber masses included in the absorbent body is oriented such that the longitudinal direction of the basic surface is along the thickness direction of the absorbent body An absorbent according to any one of the preceding claims.
The absorbent according to any one of claims 1 to 13, wherein a mass ratio of the fiber mass to the water-absorbent fiber is 20/80 to 80/20 as the former / the latter.
The absorbent according to any one of claims 1 to 14, wherein constituent fibers of the fiber mass are oriented in the plane direction of the basic surface.
The fiber mass is bound in the absorbent body by entanglement with another fiber mass or the water absorbent fiber, and is also present in a state capable of being entangled with another fiber mass or the water absorbent fiber. The absorber according to any one of 1 to 15.
The absorbent according to claim 16, wherein the total number of the fiber mass bonded by the entanglement and the fiber mass in the entangled state is more than half of the total number of the fiber mass in the absorbent.
18. The fiber bundle according to any one of claims 1 to 17, wherein 70% or more of the total number of fiber bundles having a bond with the other fiber bundle or the water-absorbent fiber is formed. The absorber as described in 1.
The absorbent according to any one of claims 1 to 18, wherein the fiber mass is derived from a non-woven fabric.
20. The hydrophilic agent according to any one of claims 1 to 19, wherein the hydrophilic agent comprises one or more selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The absorber as described in 1.
21. The absorber according to claim 20, wherein the hydrophilizing agent comprises an anionic surfactant.
22. The absorber according to claim 21, wherein the anionic surfactant comprises alkyl sulfosuccinate.
An absorbent article comprising the absorbent according to any one of claims 1 to 22.
A liquid-permeable top sheet is provided on one side of the absorbent body, and the fiber mass is present on the side relatively close from the top sheet side when the absorbent body is bisected in the thickness direction. The absorbent article as described in.
The absorbent body and a surface sheet disposed on the skin facing surface side of the absorbent body, wherein the contact angle of the synthetic fiber with water is smaller than the contact angle of the surface sheet with water, The absorbent article according to claim 23 or 24, which is equal to or more than the contact angle of the water-absorbent fiber with water.