TW201929807A - Absorbent article - Google Patents

Abstract

This absorbent article (1) is provided with an absorbent body (4) and a surface sheet (2) arranged on the skin-facing surface side of the absorbent body (4). The absorbent body (4) is configured by including an absorbent core (40) that exhibits liquid absorbency, and a core wrapping sheet (41) that covers the skin-facing surface of the absorbent core (40). The absorbent core (40) includes a water-absorbing fiber (12F) and fiber lumps (11) including fibers (11F) that exhibits a weak water-absorbency which is weaker than that of the water-absorbing fiber (12F). The ratio between the liquid diffusion surface area of the absorbent core (40) and the liquid diffusion surface area of the core wrapping sheet (41), namely, the former over the latter, is at least 0.7.

Description

Absorbent article

The present invention relates to an absorbent article such as menstrual sanitary napkin.

In general, absorbent articles such as disposable diapers and menstrual sanitary napkins include a front sheet disposed relatively close to the wearer's skin, a back sheet disposed relatively far from the wearer's skin, and an interposition It is composed of an absorber between two sheets. Typically, the absorbent body includes an absorbent core that constitutes the main body of the absorbent body, and a core-wrap material covering the surface of the absorbent core. In many cases, the absorbent core is made of water-absorbent fibers such as wood pulp. The main body is further composed of water-absorbing polymer particles. Regarding absorbers used for absorbent articles, improvement of various characteristics such as flexibility (buffering properties), compression responsiveness, and shape retention is a major issue.

As an improved technique of the absorber, for example, Patent Document 1 describes an absorber containing thermoplastic resin fibers and cellulose-based water-absorbing fibers, the thermoplastic resin fibers on the surface of the absorber on the front sheet side and the absorber Both surfaces of the back sheet side of the body are exposed. According to the absorber described in Patent Document 1, the thermoplastic resin fibers function as a framework for holding other components of the absorber such as cellulose-based water-absorbing fibers, so they are relatively soft and are less likely to wrinkle.

In addition, Patent Document 2 describes an absorber including a non-woven fabric sheet including hot-melt fibers and previously bonded between fibers to give a three-dimensional structure, and water-absorbent fibers. The non-woven fabric piece of this three-dimensional structure is manufactured by pulverizing the non-woven fabric into pieces by a crushing method such as a shredder crushing method. Therefore, due to this manufacturing method, it has an indefinite shape as described in FIGS. Substantially does not have what is considered a plane. In Patent Document 2, as a preferred form of the absorber described in the same document, there is described a case where non-woven fabric sheets are thermally fused with each other. According to the absorber described in Patent Document 2, since the nonwoven fabric sheet has a three-dimensional structure, voids are formed inside the absorber, and the recovery when absorbing moisture is improved. As a result, the water absorption performance is improved.

In addition, Patent Document 3 describes a fine fiber web having a relatively dense fine fiber core and fibers or fiber bundles extending outward from the core, and further describes that the fine fiber core is combined with wood pulp or water absorption The nonwoven web made of mixed polymer particles can be used as an absorbent body for absorbent articles. This fine fiber web is produced by pulling or tearing a raw material sheet such as a nonwoven fabric, and has an indefinite shape like the nonwoven fabric sheet described in Patent Document 2, and does not substantially have a portion that is regarded as a plane.

In addition, Patent Document 4 describes that when the absorbent body contains a water-absorbing polymer, if the absorbent body absorbs liquid and swells, it is sealed by the front sheet and the back sheet disposed above and below the absorbent body To prevent swelling of the water-absorbing polymer, in order to solve this problem, a buffer layer with high compression / compression response and liquid permeability is interposed between the front sheet and the absorber, and it is described as fragments of non-woven fabric The aggregate constitutes the buffer layer, and the thickness of the buffer layer is 10 to 40 mm. In Patent Document 4, the shape and the like of the fragments of the non-woven fabric used for the buffer layer are not specifically described.
[Prior Technical Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-16296
[Patent Document 2] Japanese Patent Laid-Open No. 2002-301105
[Patent Document 3] Japanese Patent Laid-Open No. 1-156560
[Patent Document 4] Japanese Patent Laid-Open No. 2003-52750

The present invention relates to an absorbent article having a longitudinal direction corresponding to the front-back direction of the wearer and a transverse direction orthogonal thereto, and having an absorber, and a front sheet disposed on the skin-facing side of the absorber. The above-mentioned absorbent body is composed of a liquid-absorbent absorbent core and a core-wrap material covering the skin opposite surface of the absorbent core, the absorbent core including: water-absorbent fibers; and a fiber block including water-absorbent core The fiber with weaker water absorption than the water absorbent fiber. The ratio of the liquid diffusion area of the above-mentioned absorbent core measured by the following method to the liquid diffusion area of the above-mentioned core-wrap material measured by the following method is 0.7 or more as the former / the latter.

<Measurement method of liquid diffusion area>
On an inclined surface with an angle of 45 ° relative to the horizontal plane, fix the measurement object so that the opposite side of the skin faces the inclined surface, and it takes 23 seconds to inject 1.5 g of defibrinated horse blood into the opposite side of the measurement object After being left for 3 minutes, the same amount of defibrinated horse blood is injected into the same injection site in the same time. This defibrillation horse blood injection and placement operation was repeated 6 times, and a total of 9 g of defibrillation horse blood was injected into the measurement object. After the injection operation is completed, the diffusion area of the defibrillated horse blood in the skin facing surface of the measurement object is measured, and this is taken as the liquid diffusion area of the measurement object.

The absorber described in Patent Document 1 contains synthetic fibers (thermoplastic resin fibers) in addition to cellulose-based water-absorbent fibers, so it has higher rigidity than an absorber containing only cellulose-based water-absorbent fibers as constituent fibers. Therefore, the improvement of various characteristics such as cushioning properties and compression responsiveness can be expected, but the plurality of synthetic fibers contained are independent of each other and do not form an aggregate. Therefore, the improvement effect of these various characteristics is insufficient. In the case of absorbent articles, there is a possibility that wrinkles are likely to occur and the fit becomes insufficient, especially after the absorption of body fluids such as urine and menstrual blood.

On the other hand, the synthetic fibers contained in the absorbers described in Patent Documents 2 to 4 are all synthetic fiber aggregates called nonwoven fabric sheets, fine fiber webs, etc., so improvement in cushioning properties can be expected. However, according to the findings of the present inventors, if a plurality of such weakly absorbent synthetic fiber aggregates are included in the absorbent body, the liquid permeability of the absorbent body is reduced, and as a result, the absorbent sheet reaches the absorbent body through the front sheet Body fluids on the opposite side of the skin (chip-coated) are difficult to be introduced into the absorber (absorbent core), and a large amount of body fluid remains on the opposite side of the absorber's skin, which becomes sticky or moist in the uncomfortable skin the reason. Patent Documents 2 to 4 do not describe the problem caused by the absorbent body of the weakly absorbent synthetic fiber assembly, and there is no technology to solve the problem while utilizing the advantages of the synthetic fiber assembly.

Therefore, the present invention relates to an absorbent article having an absorbent body having high liquid permeability to an absorbent core and excellent cushioning properties.

Hereinafter, the present invention will be described based on its preferred embodiments while referring to the drawings. Figures 1 and 2 show a menstrual tampon 1 as an embodiment of the absorbent article of the present invention. The sanitary napkin 1 includes: an absorber 4, which absorbs and retains body fluids; a liquid-permeable front sheet 2, which is arranged on the skin-facing side of the absorber 4 and can be in contact with the wearer's skin; and the liquid is difficult to penetrate The back sheet 3 is arranged on the non-skin-facing side of the absorber 4. As shown in FIG. 1, the sanitary napkin 1 has a longitudinal direction X corresponding to the front and back directions of the wearer and extending from the ventral side of the wearer to the dorsal side through the crotch portion, and a transverse direction Y orthogonal thereto, and, in the longitudinal direction X, It is divided into the following three areas: the longitudinal central area B, which contains the excretory portion opposite portion (excretion point) opposite the wearer's vaginal opening and other excretory portions; the front area A, which is arranged opposite to the excretory portion It is closer to the ventral side (front side) of the wearer; and the rear area C is arranged closer to the wearer's back side (rear side) than the excretory facing portion.

In this specification, "skin-facing surface" refers to the surface of the absorbent article or its constituent members (for example, the absorbent body 4) that faces the wearer's skin when worn, that is, relatively close to the wearer's skin On the other hand, the "non-skin-facing surface" refers to the surface of the absorbent article or the absorbent article in its constituent members that faces the side opposite to the skin side, that is, the side relatively away from the wearer's skin. In addition, "when wearing" here means to maintain the state of the usual proper wearing position, that is, the correct wearing position of the absorbent article.

As shown in FIG. 1, the sanitary napkin 1 has: an absorbent body 5 which is longer in the longitudinal direction X; and a pair of wings 5W, 5W, etc., which extend from the longitudinal central region of the absorbent body 5 Each of the two sides of B along the longitudinal direction X extends outward from the lateral direction Y. The absorbent body 5 constitutes the main part of the sanitary napkin 1, and includes the front sheet 2, the back sheet 3, and the absorber 4, and is divided into a front region A, a longitudinal center region B, and a rear region C in the longitudinal direction X Areas.

Furthermore, in the case where the absorbent article has wings like the sanitary napkin 1, the longitudinal central area in the absorbent article of the present invention means the longitudinal direction (length direction, X direction in the figure) of the absorbent article The region with wings, taking the sanitary napkin 1 as an example, is the region sandwiched by the root of one wing 5W in the longitudinal direction X and the root of the other wing 5W in the longitudinal direction X. In addition, the longitudinal center region in the absorbent article without wings means the region located in the middle when the absorbent article is divided into three in the longitudinal direction.

The absorber 4 is composed of a liquid-absorbent absorbent core 40 and a liquid-permeable chip covering 41 covering at least the skin-facing surface of the absorbent core 40. Like the absorbent body 5, the absorbent core 40 has a longer shape in the longitudinal direction X in plan view as shown in FIG. 1, and the longitudinal direction of the absorbent core 40 coincides with the longitudinal direction X of the sanitary napkin 1. The absorbent core The width direction of the body 40 coincides with the lateral direction Y of the sanitary napkin 1. The absorbent core 40 and the chip-wrapped material 41 may be joined by an adhesive such as a hot-melt adhesive.

In the sanitary napkin 1, the core-wrap material 41 is a continuous sheet having a width of 2 times or more and 3 times or less of the width Y of the absorptive core 40, as shown in FIG. 2, the absorbent core is coated The whole area of the skin opposite to the body 40 extends from both sides of the absorbent core 40 in the longitudinal direction X to the outside of the lateral Y, and its extension is rolled down below the absorbent core 40 and covered The entire area of the non-skin-facing surface of the absorbent core 40. In addition, in the present invention, the chip-coated material may not be such a single sheet, for example, it may also include one skin-side chip-coated material covering the skin-facing side of the absorbent core 40 and the skin It is composed of two sheets of non-skin side wrapping chip material on the non-skin-facing side of the non-skin-facing side of the absorbent core 40 covered with different bodies on the side wrapping the sheet material.

As shown in FIG. 2, the front sheet 2 covers the entire area of the skin facing side of the absorber 4. On the other hand, the back sheet 3 covers the entire area of the non-skin-facing surface of the absorber 4 and further extends from the both edges of the absorber 4 in the longitudinal direction X to the outside in the lateral direction Y, and the following side sheet 6 A side flap portion (a portion including members extending outward from the absorber 4 to the lateral Y side) is formed together. The back sheet 3 and the side sheet 6 are bonded to each other at the extensions from the both edges of the absorber 4 along the longitudinal direction X by a known bonding method such as an adhesive, heat sealing, or ultrasonic sealing. Each of the front sheet 2 and the back sheet 3 and the absorber 4 may be joined by an adhesive. As the front sheet 2 and the back sheet 3, various sheets previously used for absorbent articles such as menstrual napkins can be used without particular limitation. For example, as the front sheet 2, a non-woven fabric of a single-layer or multi-layer structure, an apertured film, or the like can be used. As the back sheet 3, a moisture-permeable resin film or the like can be used.

As shown in FIG. 1, the side wing portion protrudes greatly outward in the lateral center Y in the longitudinal center region B, whereby a pair of wing portions 5W, 5W extend on the left and right sides of the absorbent body 5 along the longitudinal direction X. The wing portion 5W has a substantially trapezoidal shape with a lower bottom (longer than the upper bottom) on the side of the absorbent body 5 in a plan view as shown in FIG. 1, and the wing portion 5W is formed on the non-skin-facing surface It is fixed to the wing adhesion part (not shown) of clothing such as shorts. The wing part 5W is folded back to the non-skin-facing side (outer surface) side of the crotch part of shorts and other clothing. The wing part adhesive part is covered with a release sheet (not shown) containing film, non-woven fabric, paper, etc. before use. In addition, on the opposite side of the skin of the absorbent body 5 that is the opposite side of the skin of the front sheet 2 in the longitudinal direction X, a pair of side sheets 6 and 6 are connected to the absorbent body 4 in plan view. The left and right side portions along the longitudinal direction X are arranged over substantially the entire length of the longitudinal direction X of the absorbent body 5. The pair of side sheets 6 and 6 are respectively joined to other members such as the front sheet 2 by a known joining method such as an adhesive using a bonding wire (not shown) extending in the longitudinal direction X.

As shown in FIGS. 1 and 2, a concave portion integrally dented toward the non-skin-facing surface side of the absorber 4 is partially formed on the skin-facing surface of the absorber 4 7. The depressed portion 7 is formed by pressing the sanitary napkin 1 from the skin facing side, that is, the front sheet side, and may also be referred to as a "pressing portion" in terms of the forming method. As the extrusion processing, a known method can be used, and examples thereof include embossing with or without heat, ultrasonic embossing, and the like. Due to the method of forming the recessed portion 7, the front sheet 2, the core-wrap 41 and the absorbent core 40 are integrally recessed on the non-skin-facing side of the absorbent core 40 (back sheet 3 side). In addition, the recessed portion 7 has a higher density than its peripheral portion (non-formed portion of the recessed portion 7) due to the method of forming it. That is, the absorbent body 5 has a high-density portion corresponding to the recessed portion 7 and a low-density portion corresponding to the non-recessed portion. At the bottom of the concave portion 7, there may be a case where the front sheet 2, the chip wrapping 41 and the absorbent core 40 are melted and integrated.

As shown in FIG. 1, the concave portion 7 is formed at least in the longitudinal central region B, more specifically, the portion of the front region A near the longitudinal central region B extends to the portion of the rear region C near the longitudinal central region B in the longitudinal direction X上 Continuous. In the sanitary napkin 1, the recessed portion 7 has a linear shape in plan view as shown in FIG. 1, and the linear recessed portion 7 has a closed ring shape in plan view. The annular recessed portion 7 has a shape that is longer in the longitudinal direction X in a plan view, and its longitudinal direction coincides with the longitudinal direction X. The annular concave portion 7 is formed in each of the front area A and the rear area C into a U-shape or an arc shape that protrudes toward the outside of the longitudinal direction X, and the top of the U-shape or arc shape is located in the lateral Y of the sanitary napkin 1 Of the center. In addition, the annular concave portion 7 is formed in the longitudinal center region B as a pair of left and right lines extending in the longitudinal direction X. In this way, the depressed portion 7 is formed so as to surround the central portion of the longitudinal central region B in the lateral direction Y.

In the sanitary napkin 1, the depth of the recessed portion 7 (the depth from the non-recessed skin facing surface in the front sheet 2) is fixed over its entire length in the longitudinal direction. The depth of the recess 7 can be set to the same range as the depth of the leak-proof groove in such an absorbent article, and is usually about 1 to 10 mm. Examples of effects that can be expected by the formation of the recessed portion 7 include the suppression of the diffusion of the liquid in the planar direction of the absorber 4, especially the lateral direction Y, and the prevention of wrinkles in the absorber 4. In addition, the shape and arrangement of the linear recesses 7 are not limited to those shown in the drawings, and can be set in the same manner as those of such absorbent articles called leak-proof grooves, etc. The shape in plan view includes straight lines and / or curves In terms of configuration, each line may be a continuous line or a dashed line (a form in which two parts with different depths are alternately arranged in the direction in which the linear recess extends).

As one of the main features of the sanitary napkin 1, an absorbent core 40 can be cited. FIG. 3 shows a part of the absorbent core 40 (non-formed part of the recess 7). As shown in FIGS. 2 and 3, the absorbent core 40 includes a fiber block 11 including a plurality of fibers (weak water-absorbing synthetic fibers) 11F, and a water-absorbing fiber 12F. The fiber block 11 is a fiber assembly in which fibers 11F are deliberately aggregated in a block shape. In contrast, the water-absorbent fibers 12F are not intentionally integrated but exist in the absorbent core 40 in a state where they can exist independently. . The fiber block 11 mainly contributes to the improvement of the flexibility, cushioning property, compression resilience, shape retention, etc. of the absorbent core 40. On the other hand, the water-absorbent fiber 12F mainly contributes to the improvement of the liquid absorption and shape retention properties of the absorbent core 40. In addition, the absorbent core 40 can also be said to be the absorber 4 itself substantially, and the following description about the absorbent core 40 is suitably applied as the description of the absorber 4 unless there is a special description. That is, the present invention includes the case where the absorber does not include the chip wrapping material and is formed only of the absorbent core. In this case, in this case, the absorber and the absorbent core have the same meaning.

In this specification, "fiber block" refers to a fiber assembly in which a plurality of fibers are aggregated to become one. Examples of the form of the fiber block include a sheet divided from a synthetic fiber sheet having a fixed size. As the fiber block, it is particularly preferable to select a non-woven fabric as a synthetic fiber sheet and cut the non-woven fabric into a specific size and shape from the non-woven fabric sheet.

In this way, the sheet-like fiber block, which is a preferred embodiment of the fiber block of the present invention, is not constituted by aggregating a plurality of fibers to form the sheet, but by a fiber sheet having a size larger than the sheet (preferably It is manufactured by cutting the nonwoven fabric (see FIG. 6). The plurality of fiber blocks contained in the absorbent body of the present invention are a plurality of lamella-shaped fiber blocks with higher setability than those manufactured by the prior arts such as Patent Documents 1 and 2.

However, as described in Patent Documents 1 to 4, the absorbent core including the weakly absorbent synthetic fiber assembly has low liquid permeability as described above, and therefore, regarding the absorber using the same, body fluids tend to remain in the coating The skin-facing side of the skin-facing side of the absorbent core has the chip-facing skin-facing side. As a result, it may cause sticky or moist feeling of uncomfortable skin. In order to solve such a problem caused by the use of weakly absorbent fibers, the present inventors conducted various studies, and as a result obtained the following insights: An effective method is to wrap the skin side of the absorbent body, which is usually first contacted with body fluids, with a chip material The liquid diffusibility in the surface direction is set to a specific range in relation to the liquid diffusibility in the surface direction of the absorbent core that is in contact with the skin-side encapsulating core material.

Based on the above findings, in the sanitary napkin 1, the liquid diffusion area of the absorbent core 40 measured by the above <liquid diffusion area measurement method> and the liquid diffusion area of the skin-side cladding material 41 measured by the same measurement method The ratio (hereinafter, also referred to as "liquid diffusion area ratio") is set to 0.7 or more for the former / the latter. If the liquid diffusion area ratio is 0.7 or more, it is easy to smoothly move body fluids from the skin-side core wrapping material 41 to the absorbent core 40, and body fluids are less likely to remain on the skin-facing surface of the skin-side wrapping core material 41, which can reduce Sticky or moist feeling of comfortable skin. From the viewpoint of more smoothly moving body fluids from the skin-side core wrapping material 41 to the absorbent core 40, the liquid diffusion area ratio is preferably 0.75 or more, further preferably 0.8 or more, and preferably 1.5 or less , Further preferably 2.0 or less.

With reference to FIG. 8, the above-mentioned <method for measuring the liquid diffusion area> is supplemented, and the measurement object S (absorbent core, chip-coated material) is set to a quadrangular shape in plan view of 240 mm × 75 mm. The measurement table 100 used for measurement has a slope 100a with an angle θ of 45 ° to the horizontal plane. The measurement object S is placed on the inclined surface 100a such that its skin-facing surface and the inclined surface 100a face each other, and further, an acrylic resin plate 101 with an area greater than the thickness of the measurement object S of 3 mm is placed on the measurement object S . As a defibrillated horse blood system that simulates blood injection into the measurement object S, a B-type viscometer (manufactured by Toki Industry Co., Ltd., model TVB-10M, measurement conditions: rotor No. 19, 30 rpm, 25 ° C, 60 seconds) is used ) The measured viscosity is 8 mPa · s. As such defibrillated horse blood, for example, defibrillated horse blood manufactured by NIPPON BIOTEST Co., Ltd. can be used, and the viscosity can be adjusted to the above-mentioned specific range by adjusting the blood cell, plasma ratio, etc. as necessary. The injection position of the defibrillated horse blood in the measurement object S is set to the center portion of the skin opposite to the measurement object S (the portion indicated by the arrow in FIG. 8), and a micro tube pump (Tokyo Ricoh Instruments Co., Ltd.) is used. Co., Ltd.) injection. A tube (not shown) is connected to the pump, and the end of the tube opposite to the connection side of the pump is connected to the measurement object S on the inclined surface 100a, and defibrillated horse blood is injected into the measurement object S through the tube . The diffusion area of the defibrillated horse blood in the surface opposite to the skin of the measurement object S can be transferred to the distribution area of the defibrillation horse blood in the measurement object S by using OHP (Overhead projector, overhead projector) sheet, and according to Conventionally, the image analysis software NexusNewQube (manufactured by Nexus) is used to process and measure the OHP sheet.

In order to set the ratio of the liquid diffusion area to 0.7 or more as described above, it is necessary to think of a composition of two or one of the absorbent core 40 and the skin-side packaged core material 41. Finding a way to improve the liquid permeability of the skin-side wrapping chip 41 is particularly high. From this point of view, the skin-side core sheet 41 is preferably a porous sheet mainly composed of pulp. In addition, unless otherwise specified, the description of "skin-side wrapping material" in this specification also applies to one continuous sheet, that is, other parts of the wrapping material 41, for example, non-skin forming the absorber 4 The opposite surface is the non-skin-side chip wrapping material disposed between the back sheet 3 and the absorbent core 40.

As the above-mentioned porous sheet preferably used as the skin-side wrapping sheet 41, a pulp sheet mainly composed of pulp can be exemplified. As the pulp sheet, paper produced by a wet papermaking method is typical. As the main component of the porous sheet, that is, pulp, cellulose-based fibers can be used. For example, conifer tree dried kraft pulp (NBKP), broad-leaved tree dried kraft pulp (LBKP), conifer dried sulfite pulp ( NBSP), thermo-mechanical pulp (TMP) and other wood pulps; bast fibers such as mulberry tree, knot incense, shear Charlotte, etc .; non-wood pulps such as chaga, bamboo, kenaf, hemp, etc., can be used alone or in combination Use 2 or more types. The content of the pulp in the porous sheet is preferably 10% by mass or more, and more preferably 50% by mass or more. The porous sheet may contain components other than pulp or other components. Examples of the other components include fillers such as talc, dyes, coloring pigments, paper strength enhancers, antibacterial agents, and pH adjusters. , Yield improvers, water resistance agents, defoamers, etc. are generally used as raw materials or additives for papermaking, and they can be used alone or in combination of two or more.

In addition, from the viewpoint of improving the liquid permeability of the skin-side chip wrapping 41 (the porous sheet), the density of the skin-side chip wrapping 41 is preferably 0.1 g / m ³ or less, and particularly preferably It is set to 0.08 g / m ³ or less. In addition, it is preferable that the density of the skin-side core sheet material 41 is preferably 0.02 g / m ³ or more, and more preferably 0.04 g / m ³ or more, because it is easy to maintain sufficient sheet strength.

In addition, from the viewpoint of the balance between liquid permeability and strength, the basis weight of the skin-side core wrapping material 41 (the porous sheet) is preferably 5 g / m ² or more, and more preferably 10 g / m ² The above is preferably 50 g / m ² or less, and more preferably 30 g / m ² or less.

In the sanitary napkin 1, as described above, as shown in FIGS. 1 and 2, a chip wrap 41 (more specifically, a skin-side chip wrap 41) and absorption are formed on the skin-facing surface of the absorber 4 The core part 40 of the absorbent core 4 is integrally recessed toward the non-skin-facing side of the absorbent body 4, at this time, with this configuration, the shape of the absorbent body 4 for the body pressure or movement of the wearer of the sanitary napkin 1 It is further stabilized, and it is expected that the suitability of the sanitary napkin 1 will be further improved. In addition, only a part of the absorbent body 4 (absorbent core 40) is formed with the recessed portion 7, as described below, the non-formed portion of the recessed portion 7 that accounts for most of the absorbent core 40 is formed by the fibers intersecting each other. The shape-retaining property is due to the fact that it is soft and has cushioning properties. Therefore, the sanitary napkin 1 can substantially directly show the characteristics of the non-forming portion of the recess 7. From the viewpoint of the balance between the shape stability and cushioning properties of the absorber 4, the ratio of the total area of the depressions 7 to the total area of the skin facing surface of the absorber 4 (absorbent core 40) (the depressions occupy Rate) is preferably 3% or more, more preferably 5% or more, and preferably 97% or less, and more preferably 95% or less.

In addition, in the sanitary napkin 1, as shown in FIG. 1, the concave portion 7 is formed so as to surround the central portion of the horizontal central region B in the lateral direction Y, thereby further improving the shape stability of the central portion of the vertical central region B Sex. The central portion of the longitudinal central area B surrounded by the recessed portion 7 is usually a portion including the above-mentioned excretory portion facing portion (drain point), which is the first to receive the body fluid discharged by the wearer of the sanitary napkin 1 and diffuse it. In this case, at this time, the shape stability of this important part is high, and thereby, it is expected that the characteristics of the liquid absorbability (leakage resistance), the fitability, and the feeling of wearing can be further improved.

Hereinafter, the absorbent core 40 will be further described.
In the absorbent core 40, a plurality of fiber blocks 11 intersect with each other or the fiber blocks 11 and the water-absorbent fibers 12F. In the absorbent core 40 of the present embodiment, a plurality of fiber blocks 11 are combined by entanglement with constituent fibers (fibers 11F, 12F) in the absorbent core 40 to form a continuous fiber block. In addition, a plurality of fiber blocks 11 may be entangled with each other, and the fiber block 11 and the water-absorbent fibers 12F may be entangled and combined. Furthermore, in general, a plurality of water-absorbent fibers 12F also interlace with each other. At least a part of the plurality of fiber blocks 11 contained in the absorbent core 40 intersects the other fiber blocks 11 or the water-absorbent fibers 12F. In the absorbent core 40, there may be a case in which a plurality of fiber blocks 11 contained therein are all intertwined to form a fiber block continuous body, or there may be a plurality of fiber block continuous bodies mixed with each other in a non-bonded state Happening. The entanglement of the fiber block 11, that is, the ease of entanglement with other fiber blocks 11 or the water-absorbent fibers 12F largely depends on the shape (number, size, distribution state) of the fiber extended portion 113 that the fiber block 11 has Etc.), by appropriately controlling the shape of the extended fiber portion 113, the intertwinability of the fiber block 11 can be improved.

The fiber block 11 is excellent in flexibility and the like. In the present embodiment, regarding the absorbent core 40, as described above, the plurality of fiber blocks 11 contained therein are combined by mutual interlacing, and further, the fiber blocks 11 and the water-absorbent fibers 12F are also interlaced by each other. In combination, it is excellent in shape retention, flexibility, cushioning, compression and resilience. When loaded into the sanitary napkin 1, it is resistant to external forces from various directions (for example, the body pressure of the wearer of the absorbent article) The flexible deformation makes the sanitary napkin 1 closely contact the wearer's body with good serviceability.

FIG. 4 schematically shows the deformed state of the absorbent core 40 when compressed by an external force F. FIG. In the absorbent core 40 in which the fiber aggregate 11 that is the fiber block 11 and the non-fiber aggregate that is the water-absorbent fiber 12F coexist, due to the difference in rigidity of the two members 11, 12F, at the boundary BL of the two members 11, 12F (Figure The broken line in 4) is particularly easy to bend, and the boundary BL functions as a bent portion when the absorbent core 40 is deformed. At this time, since the boundary BL as the bent portion usually exists throughout the entire area of the absorbent core 40, Therefore, the absorbent core 40 can be flexibly deformed in response to various external forces, and when the external force is released, it can be quickly restored to its original state by the compression and resilience of the fiber block 11. Such deformation-recovery characteristics of the absorbent core 40 can be manifested not only when the absorbent core 40 is compressed, but also when twisted. That is, the absorbent core 40 inserted into the sanitary napkin 1 is placed between the two thighs of the wearer when the sanitary napkin 1 is worn, so the absorber 4 is present when the wearer walks The movement of the two thighs is twisted around the imaginary axis of rotation extending in the longitudinal direction X, but because the absorbent core 40 has a high deformation-response characteristic, even in this case, it can be targeted The twisted external force from the two thighs is caused to easily deform and reply, so that it is not easily wrinkled, and the sanitary napkin 1 can be given a higher suitability to the wearer's body.

As described above, in the absorbent core 40, the fiber blocks 11 intersect each other or the fiber blocks 11 intersect with the water-absorbent fibers 12F. In this case, the "interlace" of the fiber blocks 11 and the like mentioned here includes the following forms A and B .
Form A: The fiber blocks 11 are combined with each other by the constituent fibers 11F of the fiber block 11 being intertwined with each other, rather than being combined by fusion.
Form B: In the natural state (the state where no external force is applied) of the absorbent core 40, the fiber blocks 11 are not combined with each other, but in the state where the external force is applied to the absorbent core 40, the fiber blocks 11 can be borrowed from each other The form in which the constituent fibers 11F are entangled with each other is combined. The "state in which external force is applied to the absorbent core 40" as used herein refers to, for example, the state in which the deforming force is applied to the absorbent core 40 during the wearing of the absorbent article to which the absorbent core 40 is applied.

In this way, in the absorbent core 40, the fiber block 11 may be combined with other fiber blocks 11 or the water-absorbent fibers 12F by being entangled with each other, that is, "interlaced", as in the form A, but also in the form B, It exists in a state where it can be interlaced with other fiber blocks 11 or water-absorbent fibers 12F, and this combination of intersecting fibers is one of the important aspects for further effectively exhibiting the above-mentioned effect of the absorbent core 40. However, in terms of shape retention, the absorbent core 40 is more preferably a “interlace” with Form A. Regardless of the form A or B, the combination using the interlacing of the constituent fibers in the absorbent core 40 does not need to be followed by components but is only formed by the intertwining of the fibers, so it is similar to the use of "fiber fusion" as described in Patent Document 2 Compared with the combination, the binding force itself is lower. Conversely, the freedom of movement of the interlinked elements (fiber block 11, water-absorbent fiber 12F) is higher. Therefore, each element can be maintained as it contains Move within the physical range of the collective body. In this way, the absorbent core 40 is relatively loosely combined with the plurality of fiber blocks 11 contained therein, or the fiber block 11 and the water-absorbent fiber 12F, and has a shape-retaining shape-retaining property that can be deformed when subjected to an external force, at a high level Take into account both shape retention, cushioning and compression response.

Furthermore, the binding state of the absorbent core 40 via the fiber block 11 need not be "interlaced", and a part of the absorbent core 40 may also include other binding forms besides intersecting, for example, using an adhesive Bonding etc.

However, for example, as a result of being integrated with other members of the absorbent article such as the recessed portion 7 in the sanitary napkin 1, the "fusion through the fiber block 11" formed on the absorbent core 40 is excluded from the absorbent core 40 The remaining part, that is, in the absorbent core 40 itself, ideally, the combination of the fiber blocks 11 or the combination of the fiber blocks 11 and the water-absorbent fibers 12F is formed only by "intersection of fibers".

In terms of further demonstrating the effect of the above-mentioned absorbent core 40, the total number of the form A, that is, the "fiber block 11 combined by interlacing" and the form B, that is, the "fiber block 11 in the interlacable state" are relatively The total number of fiber blocks 11 in the absorbent core 40 is preferably more than half, more preferably 70% or more, and more preferably 80% or more.
From the same point of view, the number of fiber blocks 11 having “interlace” in form A is preferably 70% or more of the total number of fiber blocks 11 having a junction with other fiber blocks 11 or water-absorbing fibers 12F, particularly preferably More than 80%.

As one of the main characteristics of the absorbent core 40, the outer shape of the fiber block 11 can be mentioned. FIG. 5 shows a typical shape of two fiber blocks 11. The fiber block 11A shown in FIG. 5 (a) has a rectangular column shape, more specifically, a rectangular parallelepiped shape, and the fiber block 11B shown in FIG. 5 (b) has a disk shape. The fiber blocks 11A and 11B have in common that they have two base planes 111 facing each other and a body plane 112 connecting the two base planes 111. Both the basic surface 111 and the skeleton surface 112 are considered to be substantially free of unevenness at the level applied when evaluating the degree of unevenness of the surface in an article mainly composed of such fibers.

The rectangular parallelepiped fiber block 11A of FIG. 5 (a) has 6 flat surfaces. At this time, the opposite two surfaces having the largest area among the six surfaces are the basic surfaces 111, and the remaining four surfaces are respectively Skeleton surface 112. The basic surface 111 and the skeleton surface 112 cross each other, and more specifically, are orthogonal.
The disc-shaped fiber block 11B of FIG. 5 (b) has two flat surfaces facing the circular shape in a plan view, and a curved peripheral surface connecting the two flat surfaces. In this case, the two flat surfaces are the basic surfaces 111, respectively. , The peripheral surface is the skeleton surface 112.
The fiber blocks 11A and 11B have a quadrangular shape when the skeleton surface 112 is viewed from above, and more specifically, they have a common shape in a rectangular shape.

The plurality of fiber blocks 11 contained in the absorbent core 40 are respectively fiber blocks 11A and 11B as shown in FIG. 5 and have two opposing basic surfaces 111 and a skeleton surface 112 connecting the two basic surfaces 111. The aspect of "fixed fiber assembly" is different from the non-woven fabric sheet or fine fiber web described in Patent Documents 2 and 3 as an indefinite fiber assembly. In other words, when seeing through any one fiber block 11 in the absorbent core 40 (for example, when observing with an electron microscope), the see-through shape of the fiber block 11 differs according to its viewing angle, and each The fiber block 11 has a plurality of perspective shapes. At this time, each of the plurality of fiber blocks 11 in the absorbent core 40 has a specific perspective shape having two opposed basic surfaces 111 and a skeleton surface 112 connecting the two basic surfaces 111 As one of its multiple perspective shapes. The plurality of nonwoven fabric sheets or microfiber webs contained in the absorbers described in Patent Documents 2 and 3 does not substantially have a "plane" like the basic plane 111 or the skeleton plane 112, that is, there is an expanded part, and the outer shapes are different from each other, not "Setting".

In this way, if the plurality of fiber blocks 11 included in the absorbent core 40 is a "fixed fiber assembly" formed by dividing the basic surface 111 and the skeleton surface 112, it is not as different as described in Patent Documents 2 and 3. Compared with the case of shaped fiber aggregates, the uniform dispersion of the fiber blocks 11 in the absorbent core 40 is improved, so that the fiber aggregates like the fiber blocks 11 are formulated in the absorbent core 40 to stably appear Expected effects (improvement effects such as flexibility, cushioning properties, and compression responsiveness of the absorber). Moreover, especially in the case of a rectangular parallelepiped fiber block 11 as shown in FIG. 5 (a), its outer surface includes 6 faces of 2 basic faces 111 and 4 skeleton faces 112, so it is different from FIG. 5 (b) ) Compared with the disc-shaped fiber block 11 with three outer surfaces, it can have relatively more contact opportunities with other fiber blocks 11 or water-absorbent fibers 12F, the cross-connectivity is improved, and the shape retention can also be improved Wait.

In the fiber block 11, the total area of the two basic surfaces 111 is greater than the total area of the skeleton surface 112. That is, in the rectangular parallelepiped fiber block 11A of FIG. 5 (a), the sum of the areas of the two basic faces 111 is greater than the sum of the areas of the four skeleton faces 112. Also, in FIG. 5 (b) In the disc-shaped fiber block 11B, the sum of the areas of the two basic surfaces 111 is larger than the area of the skeleton surface 112 on the peripheral surface of the disc-shaped fiber block 11B. In any of the fiber blocks 11A and 11B, the basic surface 111 is the surface having the largest area among the plural surfaces of the fiber blocks 11A and 11B.

Such a "shaped fiber assembly", that is, a fiber block 11 formed by dividing two basic planes 111 and a skeleton plane 112 crossing the two basic planes 111, that is, the fiber block 11 is realized by making the manufacturing method different from the prior art. As shown in FIG. 6, a preferred method of manufacturing the fiber block 11 is to use a cutting device such as a cutter to cut the raw fiber sheet 10bs (a sheet having the same composition as the fiber block 11 and having a larger size than the fiber block 11). Broken to shape. The plurality of fiber blocks 11 manufactured in this way are more uniform in shape and size than those manufactured by the prior art as in Patent Documents 2 and 3. FIG. 6 is a diagram illustrating a method for manufacturing the rectangular parallelepiped fiber block 11A of FIG. 5 (a). The broken line in FIG. 6 indicates a cutting line. The absorbent core 40 is provided with a plurality of fiber blocks 11 having a uniform shape and size obtained by cutting the fiber sheet into a fixed shape in this way. As described above, the raw fiber sheet 10bs is preferably a non-woven fabric.

As shown in FIG. 6, the rectangular parallelepiped fiber block 11A of FIG. 5 (a) is obtained by crossing the raw fiber sheet 10bs in the first direction D1 and crossing the first direction D1 (more specifically, orthogonally) The second direction D2 is cut with a specific length and manufactured. The two directions D1 and D2 are respectively a specific direction in the plane direction of the sheet 10bs, and the sheet 10bs is cut along the thickness direction Z orthogonal to the plane direction. In this manner, in the plurality of rectangular parallelepiped fiber blocks 11A obtained by cutting the raw fiber sheet 10bs into a so-called dicing shape, normally, the cut surface, that is, the cutting member, such as a cutter, comes into contact with the cutting device when cutting the sheet 10bs The surface is the skeleton surface 112, and the non-cut surface, that is, the surface that is not in contact with the cut device, is the basic surface 111. The basic surface 111 is the front surface and the back surface (the surface orthogonal to the thickness direction Z) of the sheet 10bs, and, as described above, is the surface having the largest area among the plural surfaces of the fiber block 11A.

Furthermore, the above description about the fiber block 11A is basically also applicable to the disk-shaped fiber block 11B of FIG. 5 (b). The essential difference from the fiber block 11A is only the cutting pattern of the raw fiber sheet 10bs. When the sheet 10bs is cut into a fixed shape to obtain the fiber block 11B, as long as the top view shape of the fiber block 11B corresponds to the sheet 10bs It can be cut into a round shape.

In addition, the outer shape of the fiber block 11 is not limited to that shown in FIG. 5, and the basic surface 111 and the skeleton surface 112 may be flat surfaces that are not curved like the surfaces 111, 112 of FIG. 5 (a), or may be As shown in FIG. 5 (b), the skeleton surface 112 (the peripheral surface of the disc-shaped fiber block 11B) is a curved surface. In addition, the basic surface 111 and the skeleton surface 112 may have the same shape and the same size. Specifically, for example, the outer shape of the fiber block 11A may be a cubic shape.

As described above, the two types of surfaces (basic surface 111, skeleton surface 112) of the fiber block 11 (11A, 11B) are classified as: the cut surface (skeletal surface 112), which is used by the cutter when manufacturing the fiber block 11 The raw fiber sheet 10bs of the cutting device is formed by cutting; and the non-cutting surface (basic surface 111), which is the surface that the sheet 10bs originally has and does not contact the cutting device. In addition, depending on whether the cut surface is different, the skeleton surface 112, which is a cut surface, has a feature that the number of fiber ends per unit area is larger than that of the basic surface 111, which is a non-cut surface. The "fiber end" mentioned here means the lengthwise end of the fiber 11F constituting the fiber 11F. Generally, the fiber end portion also exists on the non-cutting surface, that is, the basic surface 111, but the skeleton surface 112 is a cutting surface formed by cutting the raw fiber sheet 10bs, and therefore, includes the constituent fibers 11F formed by the cutting There are a plurality of fiber ends of the cut ends in the entire skeleton surface 112, that is, the number of fiber ends per unit area is greater than the number of base planes 111 per unit area.

The fiber ends present on each surface (basic surface 111, skeleton surface 112) of the fiber block 11 are useful for forming an intersection between the fiber block 11 and other fiber blocks 11 or the water-absorbent fibers 12F included in the absorbent core 40. In addition, generally, the greater the number of fiber end portions per unit area, the higher the cross-linkability, so that various characteristics such as shape retention of the absorbent core 40 can be improved. Also, as described above, the number of fiber ends per unit area in each face of the fiber block 11 is not uniform. Regarding the number of fiber ends per unit area, the size relationship of "skeletal plane 112> basic plane 111" Since it is established, the intertwinability between the fiber block 11 and other fibers (other fiber block 11 and water-absorbent fiber 12F) differs according to the surface of the fiber block 11, and the skeleton surface 112 has higher intertwinability than the basic surface 111. That is, the combination of the intersection with other fibers through the skeleton surface 112 is stronger than the combination through the basic surface 111. In one fiber block 11, the basic surface 111 and the skeleton surface 112 can be used to make it with other fibers The binding force of the fibers is poor. In general, the stronger the binding force, the more restrictive the freedom of movement of the fibers to be bonded. As the absorbent core 40 as a whole, the strength (shape retention) is improved, and conversely, the softness tends to decrease.

In this way, in the absorbent core 40, each of the plurality of fiber blocks 11 contained therein has two kinds of binding forces for other fibers (other fiber blocks 11, water-absorbent fibers 12F) around it to intersect, thereby absorbing The sexual core 40 has both moderate softness and strength (shape retention). Moreover, when the absorbent core 40 having such excellent characteristics is used as the absorbent body of an absorbent article according to the conventional practice, the wearer of the absorbent article can be provided with a comfortable wearing feeling, and effectively prevent When wearing, the wearer's body pressure and other external forces destroy the bad condition of the absorbent core 40.

In particular, as described above, the total area of the two basic surfaces 111 of the fiber block 11 (11A, 11B) shown in FIG. 5 is greater than the total area of the skeleton surface 112. Therefore, it means that the number of fiber ends per unit area is relatively small, so that the total area of the basic surface 111 with relatively low crosstalk with other fibers is larger than that of the skeleton surface 112 with the opposite properties. Therefore, the fiber block 11 (11A, 11B) shown in FIG. 5 is easier to suppress other fibers (other fiber block 11, water-absorbent fiber 12F) than the fiber block in which the fiber ends are uniformly present on the entire surface. The entanglement, even when entangled with other fibers in the periphery, is also apt to entangle with a relatively weak binding force. Therefore, it is not easy to become a large lump, and the absorbent core 40 can be provided with excellent flexibility.

On the other hand, as described above, the non-woven fabric sheet or fine fiber web described in Patent Documents 2 and 3 is manufactured by cutting the raw fiber sheet into an indefinite shape using a cutter like a milling cutter, so it does not become A sheet-shaped fiber block having a "face" shaped like a basic surface 111 or a skeleton surface 112, and a force outside the cutting process is applied to the entire fiber block during its manufacture, so the fiber ends constituting the fiber are randomly It is formed in the entire fiber block, and it is difficult to sufficiently express the above-mentioned action effect produced by the fiber end.

From the viewpoint of more surely obtaining the above-mentioned effect by the fiber end, the number N ₁ per unit area of the fiber end of the basic surface 111 (non-cut surface) and the skeleton surface 112 (cut surface) The ratio of the number N ₂ of the fiber end per unit area is raised before N ₁ <N _2. As N ₁ / N ₂ , it is preferably 0 or more, more preferably 0.05 or more, and preferably 0.90 The following is more preferably 0.60 or less. More specifically, N ₁ / N _{2 is} preferably 0 or more and 0.90 or less, and more preferably 0.05 or more and 0.60 or more.
The number N ₁ per unit area of the fiber end of the basic surface 111 is preferably 0 pieces / mm ² or more, and more preferably 3 pieces / mm ² or more, and, preferably, 8 pieces / mm ² or less, and further It is preferably 6 pieces / mm ² or less.
The number N ₂ per unit area of the fiber end of the skeleton surface 112 is preferably 5 pieces / mm ² or more, more preferably 8 pieces / mm ² or more, and, preferably, 50 pieces / mm ² or less, and more It is preferably 40 pieces / mm ² or less.
The number of fiber ends of the basic surface 111 and the skeleton surface 112 per unit area is measured by the following method.

<Method for measuring the number of fiber ends per unit area on each face of the fiber block>
For the member (fiber block) containing the fiber to be measured, double-sided paper tape (NICETACK NW-15 manufactured by Mi Qibang Co., Ltd.) was used, and the measurement piece was attached to the sample stage. Then, platinum was coated on the measurement piece. For the coating system, an ion sputtering apparatus model E-1030 (trade name) manufactured by Hitachi Naka Seiki Co., Ltd. was used, and the sputtering time was set to 120 seconds. For the cut surface of the measuring piece, a JCM-6000 type electron microscope manufactured by JEOL Co., Ltd. was used to observe the basic surface and the skeleton surface at a magnification of 100 times. In the observation screen with a magnification of 100 times, set a rectangular area of 1.2 mm in length and 0.6 mm in width at any position of the measurement target surface (basic surface or skeleton surface), and the area of the rectangular area accounts for the area of the observation screen After adjusting the viewing angle by 90% or more, measure the number of fiber ends included in the rectangular area. In the case of an observation screen with a magnification of 100 times, when the measurement target surface of the fiber block is less than 1.2 mm × 0.6 mm and the area of the rectangular area accounts for less than 90% of the entire observation screen, the observation magnification is greater than 100 times Thereafter, 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” which is the object of the number measurement is the longitudinal end of the constituent fibers of the fiber block, even if the portion of the constituent fiber other than the longitudinal end (the middle in the longitudinal direction) is from the measurement target surface Extending, the middle part in the longitudinal direction is not subject to the number measurement. Then, the number per unit area of the fiber end portion in the measurement target surface (basic surface or skeleton surface) of the fiber block is calculated by the following formula. For each of the 10 fiber blocks, the number of fiber ends per unit area in each of the basic surface and the skeleton surface is measured according to the above sequence, and the average value of the plurality of measurement values is set as the measurement target surface. The number of fiber ends per unit area.
The number of fiber ends per unit area (number / mm ² ) in the measurement target surface (basic surface or skeleton surface) of the fiber block = the number of fiber ends included in the rectangular area (1.2 × 0.6 mm) / The area of the rectangular area (0.72 mm ² )

In the case where the basic surface 111 of the fiber block 11 has a rectangular shape in plan view as the fiber block 11A shown in FIG. 5 (a), from the viewpoint of improving the uniform dispersion of the fiber block 11 in the absorber 4 The short side 111a of the rectangular shape is preferably equal to or shorter than the thickness of the absorbent core 40 containing the fiber block 11 (11A). The ratio of the length of the short side 111a to the thickness of the absorbent core 40 is preferably 0.03 or more, more preferably 0.08 or more, and preferably 1 or less, and more preferably 0.5 or less.
The thickness of the absorbent core 40 is preferably 1 mm or more, and more preferably 2 mm or more, and, preferably, 15 mm or less, and more preferably 10 mm or less. The thickness of the absorbent core 40 is measured by the following method.

<Measurement method of thickness of absorber>
The object to be measured (absorbent core 40) was placed at a horizontal position without wrinkling or bending, and the thickness of the object to be measured under a load of 5 cN / cm ² was measured. Specifically, for the thickness measurement, for example, a thickness gauge PEACOCK DIAL UPRIGHT GAUGES R5-C (manufactured by OZAKI MFG.CO. LTD.) Is used.
At this time, a flat plate (thickness 5 mm in thickness) with a round or square shape in plan view adjusted between the front end of the thickness gauge and the sheared measurement object so that the load on the measurement object becomes 5 cN / cm ² Left and right acrylic resin plates), and measure the thickness. The thickness measurement system measures 10 locations, calculates the average value thereof, and uses it as the thickness of the object to be measured.

The size and the like of each part of the fiber block 11 (11A, 11B) are preferably set as shown below. The size of each part of the fiber block 11 can be measured based on the following electron microscope photographs of the specific operation of the outer shape of the fiber block 11.
When the basic surface 111 is a rectangular shape as shown in FIG. 5 (a) in plan view, the length L1 of the short side 111a is preferably 0.3 mm or more, further preferably 0.5 mm or more, and, preferably 10 mm Below, and further preferably 6 mm or less. The length L2 of the long side 111b of the basic surface 111 of the rectangular shape in plan view is preferably 0.3 mm or more, more preferably 2 mm or more, and, preferably, 30 mm or less, and more preferably 15 mm or less.
Furthermore, as shown in FIG. 5, when the basic surface 111 is the surface having the largest area among the plurality of surfaces of the fiber block 11, the length L2 of the long side 111 b and the maximum distance between the two ends of the fiber block 11 Consistently, the maximum length of the two ends is the same as the diameter of the base surface 111 of the circular-shaped fiber block 11B in the plan view.
The ratio of the length L1 of the short side 111a to the length L2 of the long side 111b in terms of L1 / L2 is preferably 0.003 or more, more preferably 0.025 or more, and preferably 1 or less, and more preferably 0.5 or less. Furthermore, in the present invention, the top view shape of the basic surface 111 is not limited to the rectangular shape as shown in FIG. 5 (a), but may also be a square shape, that is, the lengths L1 and L2 of the two orthogonal sides The ratio can also be 1 in terms of L1 / L2.
The thickness T of the fiber block 11, that is, the length T between the two opposed basic surfaces 111 is preferably 0.1 mm or more, and more preferably 0.3 mm or more, and, preferably, 10 mm or less, and more preferably 6 mm or less.

In addition, the absorbent core 40 preferably has mechanical isotropy, so that all the surfaces of the absorbent core 40 can easily obtain the effect due to the presence of the fiber block 11. Therefore, it is preferable that the fiber blocks 11 are distributed at a high density and uniformly throughout the absorbent core 40. From this point of view, it is preferable that the overlapping portions of the plurality of fiber blocks 11 exist in an arbitrary unit area of 10 mm square when viewed in projections in two directions orthogonal to each other of the absorbent core 40. Symbols 11Z in FIGS. 3 and 4 indicate overlapping portions of the plurality of fiber blocks 11. As the "projection observation in two directions orthogonal to each other" mentioned here, typically, the projection observation in the thickness direction of the absorbent core (absorber) can be cited (that is, for the absorbent core, from Skin-facing surface or non-skin-facing surface), and projection observation in a direction orthogonal to the thickness direction (that is, when the absorbent core is viewed from its side).

7 (a) shows an electron microscope photograph of an example of the fiber block of the present invention, and FIG. 7 (b) shows a diagram schematically showing the fiber block 11 according to the electron microscope photo. As shown in FIG. 7, the plurality of fiber blocks 11 included in the absorbent core 40 may include a body portion 110 and fibers 11F extending from the body portion 110 to the outside and formed with the body portion 110. Those with a lower fiber density (less number of fibers per unit area) extend out of the fiber portion 113. Furthermore, the absorbent core 40 may also include the fiber block 11 without the extended fiber portion 113, that is, the fiber block 11 including only the body portion 110. The extended fiber portion 113 is one of the fiber ends existing on each surface (basic surface 111, skeleton surface 112) of the fiber block 11 described above, and is a fiber extending out of each surface of the fiber block 11 among the fiber ends Ends.

The body portion 110 is a portion formed by dividing the two opposing basic surfaces 111 and the skeleton surface 112 connecting the two basic surfaces 111. The body portion 110 is the part that constitutes the main body of the fiber block 11 and forms the fixed shape of the fiber block 11. The various characteristics of the fiber block 11 such as high flexibility, cushioning, compression and resilience are largely largely Depends on the body part 110. On the other hand, the extended fiber portion 113 mainly contributes to the improvement of the intertwining property between the plurality of fiber blocks 11 contained in the absorbent core 40 or between the fiber blocks 11 and the water-absorbent fibers 12F, and the protection of the absorbent core 40 The improvement in formability is directly related, and in addition, it also affects the uniform dispersion in the absorbent core 40 of the fiber block 11, etc., and can indirectly reinforce the effect produced by the body portion 110.

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

The operation of specifying the outer shape of the body portion 110 of the fiber block 11 included in the absorbent core 40 can be achieved by focusing on the difference in the fiber density in the absorbent core 40 (the number of fibers per unit area) or The type of fiber, the difference in fiber diameter, etc. are confirmed by checking the "boundary" between the main body 110 and other parts. The body portion 110 has a higher fiber density than the extended fiber portion 113 existing around it. In general, the synthetic fibers and the water-absorbent fibers 12F (typically, cellulose-based fibers) constituting the fibers of the body portion 110 (Fibers) differ in quality and / or size, so even if the absorbent core 40 in which a plurality of fiber blocks 11 and water-absorbent fibers 12F are mixed, the above-mentioned boundary can be easily confirmed by focusing on the above aspects. The boundary confirmed in this way is the periphery (edge) of the basic surface 111 or the skeleton surface 112, and the basic surface 111 and the skeleton surface 112 are specified by the boundary confirmation operation, and then the body portion 110 is specified. This boundary confirmation operation can be performed by using an electron microscope to observe the object (absorbent core 40) at a plurality of observation angles as necessary. Especially in the case where the fiber block 11 included in the absorbent core 40 is like the fiber blocks 11A and 11B shown in FIG. 5, "the total area of the two basic surfaces 111 is greater than the total area of the skeleton surface 112", especially When the base surface 111 becomes the surface with the largest area of the fiber block 11, the base surface 111 with a larger area can be specified relatively easily, so that the outer shape of the body portion 110 can be smoothly specified.

As shown in FIG. 7, the extended fiber portion 113 includes constituent fibers 11F of the main body portion 110 extending outward from at least one of the basic surface 111 and the skeleton surface 112 forming the outer surface of the main body portion 110. FIG. 7 is a plan view of the fiber block 11 from the side of the base surface 111 (the surface having the largest area among the plurality of surfaces of the fiber block 11), and the fibers 11F are formed by extending a plurality of skeleton surfaces 112 crossing the base surface 111.延 出 纤维 部 113.

The shape of the extended fiber portion 113 is not particularly limited. The extended fiber portion 113 may include one fiber 11F, and may include a plurality of fibers 11F as the extended fiber bundle portion 113S described below. Further, the extended fiber portion 113 includes the lengthwise end of the fiber 11F extending from the body portion 110, but there may be portions other than such fiber ends (excluding the both ends in the longitudinal direction) Middle section). That is, in the fiber block 11, there are both ends in the longitudinal direction constituting the fiber 11F in the body portion 110, and the other portion, that is, the middle portion in the longitudinal direction extends (protrudes) outward from the body portion 110 in a ring shape In this case, the extended fiber portion 113 in this case includes an annular protruding portion of the fiber 11F.

As described above, one of the main functions of the extended fiber portion 113 is to make the plural fiber blocks 11 contained in the absorbent core 40 intersect each other, or the fiber blocks 11 and the water-absorbent fibers 12F intersect each other. Generally, if the extension length of the extended fiber portion 113 from the main body portion 110 becomes longer, or the thickness of the extended fiber portion 113 becomes thicker, or the number of extended fiber portions 113 of one fiber block 11 increases , The connection between the objects interlaced through the extended fiber portion 113 becomes stronger and it is not easy to release the interlacing, so the specific effects of the present invention can be obtained more stably.

In the case where the fiber block 11 is obtained by cutting the raw fiber sheet 10bs into a fixed shape as shown in FIG. 6, the extended fiber portion 113 is relatively present on the skeleton surface 112, which is the cut surface, relative to the Therefore, it does not exist at all on the non-cut surface, that is, the basic surface 111, or even if it exists, the number is less than the skeleton surface 112. In this way, the reason why the extended fiber portion 113 exists on the skeleton surface 112 as a cut surface is that most of the extended fiber portion 113 is "fine hair" generated by cutting the raw fiber sheet. That is, the skeleton surface 112 formed by the cutting of the raw fiber sheet 10bs is rubbed as a whole by a cutting device such as a cutter when it is cut, so it is easy to form fine hairs including the constituent fibers 11F of the sheet 10bs, and easy So-called fluff occurs. Although it also differs depending on the type of the raw fiber sheet, if the interval between the cutting lines is shortened or the cutting speed is slowed, the extended fiber portion 113 can be easily formed, and the length can be adjusted. On the other hand, the non-cutting surface, that is, the basic surface 111, does not have such friction with the cutting device, so it is not easy to form fine hairs and extend out of the fiber portion 113.

The interval L1a (interval in the first direction, refer to FIG. 6) and the interval L2a (interval in the second direction, refer to FIG. 6) at the time of cutting of the raw fiber sheet 10bs facilitate the formation of the extended fiber portion 113 From the viewpoints such as and the viewpoint of ensuring the size necessary for the fiber block 11 to exhibit a specific effect, it is preferably 0.3 mm or more, more preferably 0.5 mm or more, and, preferably, 30 mm or less, and further It is preferably 15 mm or less.

As shown in FIG. 7, the fiber block 11 has an extended fiber bundle portion 113S including a plurality of fibers 11F extending outward from the main body portion 110, more specifically, from the skeleton surface 112 as one of the extended fiber portions 113. At least one of the extended fiber portions 113 of the fiber block 11 may be the extended fiber bundle portion 113S. The extended fiber bundle portion 113S is composed of a plurality of fibers 11F extended from the skeleton surface 112, and is characterized by a longer extension length from the skeleton surface 112 than the extended fiber portion 113. The extended fiber bundle portion 113S may also exist on the base surface 111, but typically, as shown in FIG. 7, it exists on the skeleton surface 112, and does not exist on the base surface 111 at all, or even if it exists, the number is less than the skeleton surface 112. The reason is the same as the reason that the extended fiber portion 113 mainly exists on the skeleton surface 112 which is a cut surface, as described above.

The fiber block 11 has such an extended fiber bundle portion 113S, which can also be called a long and thick large extended fiber portion 113, whereby the intersection between the fiber blocks 11 or the fiber block 11 and the water-absorbent fiber 12F is further enhanced As a result, the specific effect of the present invention due to the presence of the fiber block 11 can be obtained more stably. The extended fiber bundle portion 113S is easily formed by performing the cutting of the raw fiber sheet 10bs under the above-described condition that is easy to fluff (see FIG. 6).

The extension length of the extended fiber bundle portion 113S from the body portion 110, that is, the extension length from the skeleton surface 112 (cut surface) is preferably 0.05 mm or more, and more preferably 0.15 mm or more, and, preferably, 7 mm Below, and further preferably 4 mm or less. The extended length of the extended fiber bundle portion 113S can be measured in the specific operation (boundary confirmation operation) of the outer shape of the fiber block 11 described above. Specifically, for example, using a microscope manufactured by Keyence (50 times magnification), a double-sided tape made of 3M (share) is attached to the surface of a transparent sample stage made of acrylic, and the fiber block 11 is placed thereon and fixed Then, after specifying the outer shape of the fiber block 11 according to the above-mentioned specific operation of the outer shape, the length of the extended portion of the fiber 11F extending from the outer shape is measured, and the measured extended portion The length is defined as the extended length of the extended fiber bundle portion 113S.

The extended fiber bundle portion 113S is preferably such that a plurality of constituent fibers 11F are thermally fused with each other. The hot-melt portion of the extended fiber bundle portion 113S is usually compared with the other portion (non-hot-melt portion) of the extended fiber bundle portion 113S, and both ends of the extended fiber bundle portion 113S in the direction orthogonal to the longitudinal direction The pitch length (the diameter when the cross section of the hot-melt portion is circular) is longer. By making the extended fiber bundle portion 113S have such a hot-melt portion which can also be referred to as a large-diameter portion, the strength of the extended fiber bundle portion 113S itself is improved, and thereby, the fiber mass intertwined through the extended fiber bundle portion 113S 11 The intersection between each other or the fiber block 11 and the water-absorbing fiber 12F is further enhanced. In addition, if the extended fiber bundle portion 113S has a hot-melt portion, there is an advantage that the extended fiber bundle portion 113S is not only in a dry state but also in the case of absorbing moisture to become a wet state, the extended The strength and shape retention of the fiber bundle portion 113S itself are also improved. Moreover, with this advantage, when the absorbent core 40 is applied to an absorbent article, it is needless to say that the absorbent core 40 is in a dry state, even when absorbing body fluids such as urine or menstrual blood excreted by the wearer In the case of being in a wet state, the above-mentioned effect due to the presence of the fiber block 11 can also be stably obtained. Such an extended fiber bundle portion 113S having a hot-melt portion can be used in the cutting step of the raw fiber sheet 10bs of the fiber block 11 which is the manufacturing step of the fiber block 11 shown in FIG. The "fiber sheet of the hot-melt portion of the fibers" is manufactured as the raw fiber sheet 10bs.

The constituent fibers 11F of the fiber block 11 include "weakly absorbent" fibers having lower water absorption than the water absorbent fibers 12F. The fiber used for the weak water absorption of the fiber 11F is preferably a weak water absorption synthetic fiber. The fibers 11F constituting the fiber block 11 are weakly absorbent fibers, not only when the absorbent core 40 is in a dry state, but also when it is in a wet state when absorbing moisture (body fluid such as urine or menstrual blood). The above-mentioned effects (increasing effects of shape retention, flexibility, cushioning properties, compression resilience, non-wrinkling properties, etc.) due to the presence of the fiber block 11 are stably obtained. The content of the weak water-absorbent fibers constituting the fiber 11F in the fiber block 11 is preferably 90% by mass or more, and most preferably 100% by mass relative to the total mass of the fiber block 11, that is, the fiber block 11 is only weakly water-absorbent Fiber formation. Especially when the weak water-absorbent fiber constituting the fiber 11F is a non-water-absorbent fiber, the above-mentioned effect due to the presence of the fiber block 11 can be obtained more stably.

In this specification, the term "water absorption" is, for example, assuming that the pulp has water absorption, which can be easily understood by the manufacturer. Similarly, thermoplastic fibers can be easily understood as fibers that are less water-absorbing than pulp, and are non-water-absorbing fibers. On the other hand, the degree of water absorption of the fiber can be compared with the difference in relative water absorption according to the value of the moisture content measured by the following method (the difference between the water-absorbing fiber and the fiber whose water absorption is weaker than it), and can also Define better scope. The greater the value of the moisture content, the stronger the water absorption of the fiber. As the water-absorbent fiber of the present invention, the moisture content is preferably 6% or more, and more preferably 10% or more. On the other hand, the moisture content of the weakly hydrophilic fiber of the present invention is preferably less than 6%, and more preferably less than 4%. Furthermore, when the moisture content is less than 6%, the fiber can be judged as non-absorbent fiber. That is, the weakly hydrophilic fiber of the present invention is preferably a non-absorbent fiber.

<Measurement method of moisture content>
The moisture content is calculated using the moisture content test method of JIS P8203. That is, after leaving the fiber sample in a test room at a temperature of 40 ° C. and a relative humidity of 80% RH for 24 hours, the weight W (g) of the fiber sample before the absolute drying treatment was measured in the room. Thereafter, it was allowed to stand in an electric dryer (for example, manufactured by ISUZU Manufacturing Co., Ltd.) at a temperature of 105 ± 2 ° C for 1 hour to perform absolute drying of the fiber sample. After the absolute drying treatment, in a standard state laboratory with a temperature of 20 ± 2 ° C and a relative temperature of 65 ± 2%, with Saran Wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd. covering the fiber sample, replace Si silicone rubber (for example, Toyota Chemical Co., Ltd.) is placed in a glass dryer (for example, manufactured by (Tech Co., Ltd.)), and it is left to stand until the temperature of the fiber sample becomes 20 ± 2 ° C. After that, the constant amount W '(g) of the fiber sample is weighed, and the moisture content of the fiber sample is obtained from the following formula. Moisture rate (%) = (W－W '/ W') × 100

Also, from the viewpoint that the absorbent core 40 can exhibit excellent effects in terms of shape retention, flexibility, cushioning properties, compression responsiveness, and wrinkle resistance in any state of the dry state and the wet state, In other words, the fiber block 11 preferably has a three-dimensional structure formed by thermal fusion of a plurality of thermoplastic fibers.

Furthermore, in order to obtain such a fiber block 11 in which a plurality of hot-melt portions are dispersed three-dimensionally, the synthetic fiber as the non-absorbent fiber used as the constituent fiber 11F of the fiber block 11 is preferably a thermoplastic fiber. Also, as described above, the extended fiber bundle portion 113S preferably has a hot-melt portion. In this case, by forming the fiber 11F of the fiber block 11 as a thermoplastic fiber, a preferable form of the extended fiber bundle portion 113S can also be obtained. .

In order to obtain a fiber block 11 in which a plurality of hot-melt portions are three-dimensionally dispersed, it is sufficient if the raw fiber sheet 10bs (refer to FIG. 6) is constructed in the same manner, and, as described above, such a plurality of hot-melt portions is three-dimensionally The dispersed raw fiber sheet 10bs can be produced by subjecting a fibrous web or nonwoven fabric mainly composed of thermoplastic fibers to heat treatment such as hot air treatment.

The non-water-absorbent synthetic resin, which is preferably a raw material constituting the fiber 11F of the fiber block 11, is a thermoplastic resin, for example, polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate Polyamides such as nylon 6, nylon 66; polyacrylic acid, polyalkyl methacrylate, polyvinyl chloride, polyvinylidene chloride, etc., can be used alone or in combination of two or more. In addition, the fiber 11F may be a single fiber including a single thermoplastic resin or a blended polymer obtained by mixing two or more types of synthetic resins containing a thermoplastic resin, or may be a composite fiber. The composite fiber mentioned here refers to a synthetic fiber (thermoplastic fiber) obtained by compounding two or more kinds of synthetic resins with different compositions and spinning simultaneously using a spinning head, and a plurality of components are respectively in the longitudinal direction of the fiber The continuous structure is connected to each other in a single fiber. The shape of the composite fiber includes a core-sheath type and a side-by-side type, and is not particularly limited.

Further, regarding the fiber block 11, from the viewpoint of further improving the introduction of body fluids during initial excretion, the contact angle with water measured by the following method is preferably not more than 90 degrees, especially 70 degrees or less. Such fibers are obtained by treating the above-mentioned weakly water-absorbing fibers, preferably non-water-absorbing fibers, with a hydrophilizing agent in accordance with conventional practice. As the hydrophilizing agent, a common surfactant can be used.

<Measurement method of contact angle>
The fiber was taken out from the measurement object (absorbent core, fiber block), and the contact angle of water relative to the fiber was measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. was used. The contact angle is measured using deionized water. The amount of liquid ejected from the ink jet type water droplet ejection part (CTC-25 manufactured by Cluster Technology Co., Ltd., with an ejection part aperture of 25 μm) was set to 20 picoliters, and the water droplet was dropped directly above the fiber. Record the drip situation to a high-speed recording device connected to a horizontally set camera. From the viewpoint of image analysis later, the recording device is ideally a personal computer equipped with a high-speed capture device. In this measurement, the image is recorded every 17 msec. In the recorded images, by the accompanying software FAMAS (the software version is set to 2.6.2, the analysis method is set to the droplet method, the analysis method is set to the θ / 2 method, and the image processing algorithm is set to no reflection, Figure The image processing image mode is set to the frame, the limit level is set to 200, and no curvature correction is performed) image analysis is performed on the initial image of the water drop dripping to the fiber, and the surface of the water drop and the air and the fiber are calculated Angle and set it as the contact angle. The fiber removed from the measurement object is cut to a fiber length of 1 mm, and the fiber is placed on the sample table of the contact angle meter and maintained at a level. Measure the contact angle of two different parts for each fiber. Measure the contact angle of N = 5 to one decimal place, and define the average value of the measured values of 10 parts (rounded off to the second digit after the decimal point) as the contact angle of the fiber with water. The measurement environment was set at room temperature 22 ± 2 ° C and humidity 65 ± 2% RH.

In addition, when the absorber (absorbent core) to be measured is used as a constituent member of other articles such as absorbent articles and the absorber is taken out for evaluation and measurement, the absorber is subjected to adhesives, fusion, etc. In the case of fixing to other structural members, within the range that does not affect the contact angle of the fiber, remove the adhesive force after removing the adhesive force by using cold air such as blowing cold spray, etc. This sequence is common to all determinations in the specification of this case.

As the water-absorbent fiber 12F, water-absorbent fibers previously used as a material for forming the absorbent body of such absorbent articles can be used, for example, wood pulp such as conifer pulp or broad-leaf pulp, non-wood pulp such as cotton pulp or hemp pulp Natural fiber; modified pulp such as cationized pulp, mercerized pulp, etc .; one kind of these can be used alone or two or more kinds can be mixed and used. Among the water-absorbing fibers, particularly preferred are cellulose-based water-absorbing fibers.

In the absorbent core 40, the content mass ratio of the fiber block 11 and the water-absorbent fiber 12F is not particularly limited, and it is appropriate according to the types of the constituent fibers (weak water-absorbing synthetic fiber) 11F and the water-absorbent fiber 12F of the fiber block 11 Just adjust. For example, when the constituent fibers 11F of the fiber block 11 are non-absorbent fibers, that is, thermoplastic fibers, and the water-absorbent fibers 12F are cellulose-based water-absorbent fibers, from the viewpoint of more surely obtaining the specific effect of the present invention The content of the fiber block 11 and the water-absorbent fiber 12F is preferably 20/80 to 80/20, more preferably 40/60 to 60/40 in terms of the former (fiber block 11) / the latter (water-absorbent fiber 12F) .

The content of the fiber block 11 in the absorbent core 40 is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 80% by mass relative to the total mass of the absorbent core 40 in the dry state. % Or less, and more preferably 60% by mass or less.
The content of the water-absorbent fibers 12F in the absorbent core 40 is preferably 20% by mass or more, and more preferably 40% by mass or more, and preferably 80% with respect to the total mass of the absorbent core 40 in the dry state. The mass% or less is more preferably 60 mass% or less.

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

The absorbent core 40 may contain components other than the fiber block 11 and the water-absorbent fiber 12F. As other components, a water-absorbent polymer may be exemplified. As the water-absorbing polymer, particles are generally used, but fibers may also be used. When a particulate superabsorbent polymer is used, its shape can be any of spherical, block, bag or indefinite. The average particle diameter of the water-absorbing polymer is preferably 10 μm or more, more preferably 100 μm or more, and preferably 1000 μm or less, and more preferably 800 μm or less. As the water-absorbing polymer, polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid can be generally used. Examples thereof include polyacrylic acid and its salts, and polymethacrylic acid and its salts.

The content of the water-absorbent polymer in the absorbent core 40 is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 60% relative to the total mass of the absorbent core 40 in the dry state. The mass% or less is more preferably 40 mass% or less.
The basis weight of the water-absorbing 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, still more preferably 70 g / m ² or less.

The basis weight of the absorbent core 40 should just be adjusted suitably according to the use etc. For example, when the use of the absorbent core 40 is an absorbent body for absorbent articles such as disposable diapers or menstrual sanitary napkins, the basis weight of the absorbent core 40 is preferably 100 g / m ² or more, and more preferably It is 200 g / m ² or more, and preferably 800 g / m ² or less, and more preferably 600 g / m ² or less.

The absorbent core 40 having the above-mentioned structure and the absorbent article like the sanitary napkin 1 provided with the absorbent core 40 are soft and excellent in cushioning properties, and also have excellent compression and responsiveness, and deform well in response to external forces If the external force is released, it will quickly return to its original state. The characteristics of an absorbent article having such an absorber (absorbent core) can be evaluated using the compression work energy (WC) and the reply work energy (WC ') as a scale. Compression work is a measure of the cushioning properties of absorbent articles. It can be evaluated that the larger the WC value, the higher the cushioning properties. Response energy is a measure of the degree of response when an absorbent article is compressed and released from compression. It can be evaluated that the greater the WC 'value, the higher the compression response. In addition, considering the function of the absorbent core 40 that absorbs and retains the liquid, not only in the dry state, but also in the case where the absorbed body fluids and the like become wet, the absorbent article preferably has a larger WC value and WC 'value. . In order to make the absorbent article have such characteristics in a wet state, as described above, an effective method is to use non-absorbent synthetic fibers such as thermoplastic fibers as the constituent fibers 11F of the fiber block 11.

The compressive energy (d-WC) of the absorbent article in the dry state is preferably 80 mN · cm / cm ² or more, and more preferably 90 mN · cm / cm ² or more, and, preferably, 150 mN · cm / cm ² or less, and more preferably 110 mN · cm / cm ² or less.
The compressive energy (w-WC) of the absorbent article in the wet state is preferably 70 mN · cm / cm ² or more, and more preferably 80 mN · cm / cm ² or more, and, preferably, 150 mN · cm / cm ² or less, and more preferably 110 mN · cm / cm ² or less.

The dry work energy of the absorbent article (d-WC ') is preferably 34 mN · cm / cm ² or more, and more preferably 44 mN · cm / cm ² or more, and, preferably, 150 mN · cm / cm ² or less, and more preferably 60 mN · cm / cm ² or less.
The wet energy of the absorbent article (w-WC ') is preferably 15 mN · cm / cm ² or more, more preferably 25 mN · cm / cm ² or more, and preferably 150 mN · cm / cm ² or less, and more preferably 55 mN · cm / cm ² or less.

<Measurement method of compression work (WC) and reply work (WC ')>
It is generally known that the compressive energy (WC) and the reply energy (WC ') of absorbent articles can be expressed by measured values using KES (KAWABATA EVALUATION SYSTEM) manufactured by Kado Technology Co., Ltd. (reference: standardization of texture evaluation And analysis (2nd edition), author Kawabata Jixiong, published on July 10, 1985). Specifically, the automatic compression test device KES-G5 manufactured by Jiaduo Technology Co., Ltd. can be used to measure the compression work and the response work. The measurement sequence is as follows.
Install the "absorbent article with absorbent body (menstrual pad)" as a sample on the test stand of the compression test device. Next, the sample was compressed between steel plates having a circular plane with an area of 2 cm ² . The compression speed is set to 0.02 cm / sec, and the maximum compression load is set to 490 mN / cm ² . The response process is also measured at the same speed. Compression work (WC) and response work (WC ') are expressed by the following formulas. In the formula, T _m and T _o respectively represent the thickness under the load of 490 mN / cm ² and the thickness under the load of 4.9 mN / cm ² . In addition, P _a represents the load (mN / cm ² ) during the measurement (compression process), and P _b represents the load (mN / cm ² ) during the measurement (reply process).

[Number 1]

[Number 2]

In addition, the measurement object of the above measurement method, namely, "absorbent article with an absorbent body in a dry state" is prepared by placing the absorbent article in a dry state in an environment with a temperature of 23 ° C and a relative humidity of 50% RH for 24 hours . In addition, the measurement object of the above-mentioned measurement method, that is, "absorbent article with an absorbent body in a wet state" is to place the absorbent article in a dry state horizontally with the front sheet side (skin-facing side) facing the upper side. Place an elliptical injection port (long diameter 50 mm, short diameter 23 m) on the front sheet. Inject 3.0 g defibrillated horse blood from the injection port. After standing for 1 minute, inject 3.0 g defibrillated horse blood. After injection 1 Prepared in minutes to keep it in its state. In addition, the defibrillated horse blood injected into the measurement object is made of defibrillated horse blood manufactured by NIPPON BIOTEST Co., Ltd. and the viscosity at a liquid temperature of 25 ° C. is adjusted to 8 cp. In the manufactured TVB-10M viscometer, the viscosity of the rotor with the rotor name L / Adp (rotor code 19) measured at a rotation speed of 12 rpm is used.

The absorbent core 40 can be manufactured in the same manner as an absorbent core (absorber) containing such a fiber material. As described above, as shown in FIG. 6, the fiber block 11 can be cut by using a cutter or the like to make a raw fiber sheet (a sheet having the same composition as the fiber block 11 and having a larger size than the fiber block 11) in A plurality of fiber blocks 11 manufactured by cutting in two directions that cross each other (orthogonal directions) are made into a "fixed fiber assembly" having a uniform shape and size (for example, the body portion 110 has a rectangular parallelepiped shape). The absorbent core 40 including the fiber block 11 and the water-absorbent fibers 12F can be manufactured, for example, according to a conventional practice using a known fiber stacking device equipped with a rotating drum. Typically, the fiber stacking device includes: a rotating drum with a concave portion for accumulation formed on the outer peripheral surface; and a duct with materials for transferring the absorbent core 40 (fiber block 11, water-absorbent fiber 12F) inside The flow path to the recess for accumulation; while rotating the rotary drum around its axis of rotation along the circumference of the rotary drum, while causing it to be generated in the flow path by suction from the inner side of the rotary drum The raw material fiber conveyed by the air flow (vacuum air) accumulates in the recess for accumulation.

In the above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-mentioned embodiments, and can be modified as appropriate.
For example, in the absorbent core of the present invention, the fiber blocks may be unevenly dispersed throughout the absorbent core, or may be unevenly distributed. As a form in which the fiber blocks are present in a concentrated manner, an absorbent core having a laminated structure of a layer composed of a fiber block and a layer composed of a water-absorbent fiber can be exemplified.
In addition, the absorbent core of the present invention may not include all the fiber blocks (weakly absorbent synthetic fiber aggregates) contained therein as a fiber aggregate shaped like the fiber block 11, as long as it does not deviate from the gist of the present invention In addition to the shaped fiber assembly, it may further include a very small amount of unshaped fiber assembly.
The absorbent article of the present invention broadly includes articles for absorbing body fluids (urine, soft stools, menstrual blood, sweat, etc.) discharged from the human body. In addition to the above-mentioned menstrual sanitary pads, it also includes menstrual shorts (shorts) and so-called straps Expansion type disposable diapers, pants type disposable diapers, incontinence pads, etc. Regarding the embodiments of the present invention described above, the following supplementary notes will be disclosed.

<1> An absorbent article having a longitudinal direction corresponding to the front and back directions of the wearer and a transverse direction orthogonal thereto, and having an absorber and a front sheet disposed on the skin-facing side of the absorber, The above-mentioned absorption system includes a liquid-absorbent absorbent core and a core-clad material covering the skin-facing surface of the absorbent core, the absorbent core including water-absorbent fibers, and containing water-absorbent fibers less than the water-absorbent core The fiber block of weakly absorbent fiber of sexual fiber; the ratio of the liquid diffusion area of the above-mentioned absorbent core measured by the following method to the liquid diffusion area of the above-mentioned chip-coated sheet material measured by the following method Counted above 0.7.
<Measurement method of liquid diffusion area>
On an inclined surface with an angle of 45 ° relative to the horizontal plane, fix the measurement object so that the opposite side of the skin faces the inclined surface, and it takes 23 seconds to inject 1.5 g of defibrinated horse blood into the opposite side of the measurement object After leaving for 3 minutes, the same amount of defibrinated horse blood is injected into the same injection site again for the same time, and the defibrinated horse blood is injected and placed 6 times repeatedly to add a total of 9 g of defibrinated horse Blood is injected into the measurement object. After the injection operation is completed, the diffusion area of the defibrillated horse blood in the skin opposite to the measurement object is measured, and this is taken as the liquid diffusion area of the measurement object.
<2> The absorbent article according to the above <1>, wherein the chip-wrapped material is a porous sheet mainly composed of pulp.
<3> The absorbent article as described in the above <1> or <2>, wherein the non-contained core wrapping material and the absorbent core are partially formed on the skin-facing surface of the absorbent body toward the absorbent body A recessed part that is integrally recessed on the opposite side of the skin.
<4> The absorbent article as described in the above <3>, wherein the absorbent article is divided into: a longitudinal central region including a discharge part opposing part facing the wearer ’s discharge part; a front region, It is arranged on the ventral side of the wearer more than the opposite part of the excretory part; and the rear region is arranged on the back side of the wearer more than the opposite part of the excretion part; the recessed part surrounds the longitudinal central region Formed in the horizontal center.
<5> The absorbent article according to any one of the above <1> to <4>, wherein the shape of the fiber block is a rectangular parallelepiped or a disc.

<6> The absorbent article according to any one of the above <1> to <5>, wherein the fiber block has a body portion having a relatively high fiber density, and exists around the body portion and is in contact with the body portion Compared to the extended fiber portion having a lower fiber density, a plurality of the above-mentioned fiber blocks are interlaced with each other, and the above-mentioned fiber blocks and the water-absorbing fibers are interlaced with each other.
<7> The absorbent article according to the above <6>, wherein the main body portion has two opposing basic surfaces and a skeleton surface connecting the two basic surfaces, and the basic surface has a quadrangular shape in a plan view.
<8> The absorbent article as described in the above <7>, wherein the total area of the two basic surfaces is larger than the total area of the skeleton surface.
<9> The absorbent article according to the above <7> or <8>, wherein the fiber block has an extended fiber bundle portion including a plurality of fibers extending outward from the frame surface.
<10> The absorbent article according to the above <9>, wherein the extended fiber bundle portion has a portion where a plurality of fibers are thermally fused with each other.
<11> The absorbent article according to the above <9> or <10>, wherein the extended length of the extended fiber bundle portion from the main body portion, preferably the extended length from the skeleton surface is 0.05 mm or more And 7 mm or less, preferably 0.15 mm or more and 4 mm or less.
<12> The absorbent article according to any one of the above <7> to <11>, wherein the basic surface has a rectangular shape in plan view, and the short side of the rectangular shape is shorter than the thickness of the absorbent body .
<13> The absorbent article as described in the above <12>, wherein the ratio of the length of the short side of the basic surface to the thickness of the absorbent body is 0.03 or more and 1 or less, preferably 0.08 or more in the former / the latter. 0.5 or less.
<14> The absorbent article as described in the above <12> or <13>, wherein the length of the short side of the basic surface is 0.3 mm or more and 10 mm or less, preferably 0.5 mm or more and 6 mm or less.
<15> The absorbent article as described in any one of the above <12> to <14>, wherein the length of the long side of the basic surface is 0.3 mm or more and 30 mm or less, preferably 2 mm or more and 15 mm the following.
<16> The absorbent article as described in any one of the above <7> to <15>, wherein the number N ₁ per unit area present at the fiber end of the basic surface and the fiber end present at the skeleton surface The ratio N ₁ / N ₂ of the number N ₂ per unit area of the portion is 0 or more and 0.90 or less, preferably 0.05 or more and 0.60 or more.
<17> The absorbent article as described in any one of the above <7> to <16>, wherein the number per unit area of the fiber end portion present on the above basic surface is 0 pieces / 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.
<18> The absorbent article as described in any one of the above <7> to <17>, wherein the number of fibers per unit area present at the fiber ends of the skeleton surface is 5 pieces / mm ² or more and 50 pieces / mm ² or less, preferably 8 pieces / mm ² or more and 40 pieces / mm ² or less.

<19> The absorbent article according to any one of the above <1> to <18>, wherein the fiber block has a three-dimensional structure in which a plurality of thermoplastic fibers are heat-fused to each other.
<20> The absorbent article according to any one of the above <1> to <19>, wherein the content mass of the fiber block and the water-absorbing fiber is 20/80 to 80/20 in terms of the former / the latter.
<21> The absorbent article according to any one of the above <1> to <20>, wherein in the absorbent body, the fiber block is bound to other fiber blocks or the water-absorbing fiber by interlacing, It also exists in a state where it can interlace with other fiber blocks or the above-mentioned water-absorbing fibers.
<22> The absorbent article as described in any one of the above <1> to <21>, wherein 70% or more of the total number of the fiber blocks having a joint portion with other fiber blocks or the water-absorbent fibers, compared It is preferred that more than 80% of the joints are formed by interlacing fibers.
<23> The absorbent article according to any one of the above <1> to <22>, wherein the fiber block is derived from non-woven fabric.
<24> The absorbent article according to any one of the above <1> to <23>, wherein the density of the chip-wrapped material is 0.1 g / m ³ or less.
<25> The absorbent article according to any one of the above <1> to <24>, wherein the density of the above chip-wrapped material is 0.1 g / m ³ or less, preferably 0.08 g / m ³ or less, and, It is 0.02 g / m ³ or more, preferably 0.04 g / m ³ or more.
<26> The absorbent article according to any one of the above <1> to <25>, wherein the basis weight of the chip-wrapped material is 50 g / m ² or less, preferably 30 g / m ² or less, and , Is 5 g / m ² or more, preferably 10 g / m ² or more.
[Example]

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

[Examples 1-2]
A menstrual sanitary napkin having the same composition as the sanitary napkin 1 shown in FIG. 1 was produced.
As the front sheet, a hot air nonwoven fabric with a basis weight of 30 g / m ² was used, and as the back sheet, a polyethylene resin film of 37 g / m ² was used. In the absorption system, the fiber block and the water-absorbent fiber are used as the fiber material of the absorbent core, and the chip-wrapped material prepared separately is used, and it is manufactured in accordance with conventional practices using a known fiber stacking device. The production of the fiber block is produced by cutting the raw fiber sheet into D-shapes according to FIG. 7.
As the raw fiber sheet of the fiber block, a hot-air non-woven fabric (having a thermoplastic fiber containing polyethylene resin and polyethylene terephthalate resin (fiber diameter 18 μm) as the basis weight of the fiber 21 g / m ² (with The fiber sheet constituting the hot-melt part of the fibers). As a water-absorbent fiber, conifer dried kraft pulp (NBKP) with a fiber diameter of 22 μm was used. The fiber block (fixed synthetic fiber assembly) used for the absorber has a rectangular parallelepiped body as shown in FIG. 5 (a). The short side 111a of the basic surface 111 is 0.8 mm and the long side 111b is 3.9 mm. The thickness T is 0.6 mm. In addition, the number of fiber ends in the basic surface 111 per unit area is 3.2 pieces / mm ² , and the number of fiber ends in the skeleton surface 112 per unit area is 19.2 pieces / mm ² . The basis weight of the absorber is 350 g / m ² and the thickness is 5.7 mm.

The details of the core-wrap material (the porous sheet described above) used in Examples 1 and 2 are as follows. (The chip package of Example 1)
Paper made of conifer dried kraft pulp (NBKP), with a basis weight of 13.5 g / m ² and a density of 0.092 g / cm ³ .
(The chip package of Example 2)
Paper with conifer sun-dried kraft pulp (NBKP) having a mercerizing treatment of 0.80 and a basis weight of 16.0 g / m ² and a density of 0.069 g / cm ³ was used.

[Comparative Example 1]
The commercially available menstrual sanitary napkin (manufactured by Unicharm Co., Ltd., trade name "Tanom Pew Slim 23cm") was directly used as Comparative Example 1. The absorption system in the menstrual sanitary napkin of Comparative Example 1 is a mixture of synthetic fibers (weakly absorbent fibers) and cellulose fibers (absorbent fibers), so it does not contain fiber blocks.

[Comparative Example 2]
Except that the absorber was changed to the following, the menstrual sanitary napkin was prepared in the same manner as in Example 1 and used as Comparative Example 2.
The absorbent body used in Comparative Example 2 used an amorphous non-woven fabric sheet as the fiber block in the absorbent core, and after covering the absorbent core with a core wrapping material, it was subjected to hot air treatment to make the absorbent core contain The non-woven fabric sheets were the same as the absorber used in Example 1 except that the non-woven fabric sheets were heat-fused to each other. In the hot air treatment process performed on the absorber described above, the mixed aggregate (length 240 mm × width 75 mm) of the nonwoven fabric sheet and pulp fibers is placed in an electric dryer (for example, manufactured by ISUZU Manufacturing Co., Ltd.) at a temperature of 150 ° C. ) Within 10 minutes, and the non-woven fabric pieces are melted with each other. The amorphous nonwoven fabric sheet used was manufactured by tearing the same hot air nonwoven fabric as used in Example 1 in any direction, and the distance between the two ends in plan view was about 25 mm.

[Comparative Example 3]
Except that the absorber was changed to the following, a menstrual tampon was prepared in the same manner as in Example 1 and used as Comparative Example 3. With regard to the absorber used in Comparative Example 3, the absorbent core does not contain fiber blocks, and only contains the above-mentioned water-absorbent fibers. As the chip wrapping material (the porous sheet described above), conifer sun-dried kraft pulp (NBKP) having a basis weight of 16.0 g / m ² and a density of 0.102 g / cm ³ was used.

[Performance evaluation]
For the menstrual pads of each example and comparative example, the liquid diffusion area of each of the absorbent core and the skin-side cladding material was measured by the above method, and the liquid diffusion area ratio (absorbent core body) was calculated based on the measured value. Liquid diffusion area / liquid diffusion area of chip package). In addition, the compression work (WC) and the response work (WC ') were measured by the above-mentioned method, and the cushioning property and the compression response were evaluated based on the measured values. The results are shown in Table 1 below.

[Table 1]

As shown in Table 1, the plural fiber blocks of each example intersect each other, and the ratio of the liquid diffusion area (liquid diffusion area of the absorbent core / liquid diffusion area of the core-wrap material) is 0.7 or more. Compared with the prior arts, that is, Comparative Examples 1 to 3, in either the dry state or the wet state, the values of the compression work (WC) and the response work (WC ') are larger. In this state, the cushioning properties and compression response are excellent. In addition, since the liquid diffusion area ratio of each example is within the above-mentioned specific range, the liquid permeability from the front sheet to the absorbent core through the skin-side core-wrap is excellent. Therefore, in each of the embodiments, the body fluid is less likely to remain on the skin-facing side of the absorber after the body fluid is excreted.
[Industry availability]

The absorbent article of the present invention has an absorber with high cushioning properties and liquid permeability. Therefore, according to the absorbent article of the present invention, after body fluid is excreted, body fluid is less likely to remain on the skin-facing side of the absorbent body, reducing sticky or moist feeling of uncomfortable skin, and can be expected to have excellent wearing feeling and suitability.

1‧‧‧ Sanitary napkin

2‧‧‧Front sheet

3‧‧‧Back sheet

4‧‧‧Absorber

5‧‧‧ Absorbent body

5W‧‧‧wing

6‧‧‧Side sheet

7‧‧‧Depression

10bs‧‧‧raw fiber sheet

11‧‧‧ fiber block

11A‧‧‧Fiber block

11B‧‧‧ Fiber block

11F‧‧‧fiber

11Z‧‧‧Overlap

12F‧‧‧absorbent fiber

40‧‧‧absorbent core

41‧‧‧Package chips

100‧‧‧ measuring table

100a‧‧‧Bevel

101‧‧‧Acrylic resin board

110‧‧‧Body

111‧‧‧ Fundamentals

111a‧‧‧short side

111b‧‧‧Long side

112‧‧‧Skeleton

113‧‧‧Extended from the fiber department

113S‧‧‧Extend the fiber bundle

A‧‧‧front area

B‧‧‧Vertical central area

BL‧‧‧Border

C‧‧‧ Rear area

D1‧‧‧First direction

D2‧‧‧ 2nd direction

F‧‧‧External force

L1‧‧‧Length

L1a‧‧‧Interval

L2‧‧‧Length

L2a‧‧‧Interval

S‧‧‧Measurement target

T‧‧‧thickness

X‧‧‧Portrait

Y‧‧‧horizontal

Z‧‧‧thickness direction

Fig. 1 is a plan view schematically showing a part of the skin facing side (front sheet side) of an example of a menstrual sanitary napkin according to an embodiment of the absorbent article of the present invention.

FIG. 2 is a schematic cross-sectional view taken along the line I-I in FIG. 1.

Fig. 3 is a schematic perspective view of a part of an absorbent core provided in the absorbent article shown in Fig. 1.

FIG. 4 is a diagram schematically showing the deformation state of the absorbent core shown in FIG. 3 when compressed.

5 (a) of FIG. 5 is an electron microscope photograph of an example of the fiber block of the present invention (observation magnification is 25 times), and FIG. 5 (b) is a schematic representation of the fiber block of the electron microscope photo as shown in FIG. Picture of the fiber mass contained in the absorber.

FIG. 6 is an explanatory diagram of the method of manufacturing the fiber block of the present invention.

7 (a) and 7 (b) of FIG. 7 are schematic perspective views of the body portion of the fiber block of the present invention, respectively.

FIG. 8 is an explanatory diagram of the measurement method of the liquid diffusion area.

Claims (26)

An absorbent article having a longitudinal direction corresponding to the front and back directions of the wearer and a transverse direction orthogonal to the wearer, and having an absorber and a front sheet disposed on the skin-facing side of the absorber, The above-mentioned absorption system includes a liquid-absorbent absorbent core and a core-clad material covering the skin-facing surface of the absorbent core, the absorbent core including water-absorbent fibers, and containing water-absorbent fibers less than the water-absorbent core Fiber blocks of weakly absorbent fibers of sexual fibers; The ratio of the liquid diffusion area of the above-mentioned absorbent core measured by the following method to the liquid diffusion area of the above-mentioned core-wrap material measured by the following method is 0.7 or more, <Measurement method of liquid diffusion area> On an inclined surface with an angle of 45 ° relative to the horizontal plane, fix the measurement object so that the opposite side of the skin faces the inclined surface, and it takes 23 seconds to inject 1.5 g of defibrinated horse blood into the opposite side of the measurement object After leaving for 3 minutes, the same amount of defibrinated horse blood is injected into the same injection site again for the same time, and the defibrinated horse blood is injected and placed 6 times repeatedly, a total of 9 g of defibrinated horse Blood is injected into the measurement object. After the injection operation is completed, the diffusion area of the defibrillated horse blood in the skin opposite to the measurement object is measured, and this is taken as the liquid diffusion area of the measurement object. The absorbent article according to claim 1, wherein the chip-wrapping material is a porous sheet mainly composed of pulp. The absorbent article according to claim 1, wherein on the skin-facing surface of the absorbent body, a depression is integrally formed in which the chip-wrap and the absorbent core are integrally recessed toward the non-skin-facing surface side of the absorbent body unit. The absorbent article according to claim 3, wherein the above-mentioned absorbent article is longitudinally divided into: a longitudinal central area, which includes an excretory portion facing portion opposite to the wearer's excretory portion; a front area, which is disposed closer to the excretion The opposite part is closer to the ventral side of the wearer; and the rear area, which is arranged closer to the back side of the wearer than the opposite part of the excretory part; The concave portion is formed so as to surround the lateral central portion of the longitudinal central area. The absorbent article according to claim 1, wherein the fiber block is shaped like a rectangular parallelepiped or a disc. The absorbent article according to claim 1, wherein the fiber block has a body portion having a relatively high fiber density, and an extended fiber portion existing around the body portion and having a lower fiber density than the body portion, A plurality of the fiber blocks are interlaced with each other, and the fiber block and the water-absorbent fibers are interlaced with each other. The absorbent article according to claim 6, wherein the body portion has two opposed basic surfaces and a skeleton surface connecting the two basic surfaces, and the basic surface has a quadrangular shape in plan view. The absorbent article according to claim 7, wherein the total area of the above two basic faces is greater than the total area of the above skeleton face. The absorbent article according to claim 7, wherein the fiber block has an extended fiber bundle portion including a plurality of fibers extending outward from the frame surface. The absorbent article according to claim 9, wherein the extended fiber bundle portion has a portion where a plurality of fibers are thermally fused with each other. The absorbent article according to claim 9, wherein the extended length of the extended fiber bundle portion from the main body portion is 0.05 mm or more and 7 mm or less. The absorbent article according to claim 7, wherein the basic surface has a rectangular shape in a plan view, and the short side of the rectangular shape is shorter than the thickness of the absorbent body. The absorbent article according to claim 12, wherein the ratio of the length of the short side of the basic surface to the thickness of the absorbent body is 0.03 or more and 1 or less as the former / the latter. The absorbent article according to claim 12, wherein the length of the short side of the above basic surface is 0.3 mm or more and 10 mm or less. The absorbent article according to claim 12, wherein the length of the long side of the above basic plane is 0.3 mm or more and 30 mm or less. The requested item 7 of the absorbent article, which is present in the amount per unit area of the N-terminal portion of the fibers of the above-described fundamentals present in _an amount per unit surface area of the fibrous skeleton of the end portion of the ratio N ₁ N ₂ / N ₂ is 0 or more and 0.90 or less. The absorbent article according to claim 7, wherein the number per unit area present at the fiber end of the above-mentioned basic plane is 0 pieces / mm ² or more and 8 pieces / mm ² or less. The absorbent article according to claim 7, wherein the number per unit area of the fiber end portion present on the skeleton surface is 5 pieces / mm ² or more and 50 pieces / mm ² or less. The absorbent article according to claim 1, wherein the fiber block has a three-dimensional structure formed by thermal fusion of a plurality of thermoplastic fibers. The absorbent article according to claim 1, wherein the content mass of the fiber block and the water-absorbing fiber is 20/80 to 80/20 in terms of the former / the latter. The absorbent article according to claim 1, wherein in the above-mentioned absorbent body, the fiber block can be combined with other fiber blocks or the above-mentioned water-absorbent fibers by interlacing, and can also be entangled with other fiber blocks or the above-mentioned water-absorbent fibers. The state exists. The absorbent article according to claim 1, wherein more than 70% of the total number of the fiber blocks having a joint portion with other fiber blocks or the water-absorbent fibers is formed by intersecting fibers at the joint portion. The absorbent article according to claim 1, wherein the fiber block is derived from non-woven fabric. The absorbent article according to claim 1, wherein the density of the above-mentioned chip wrapping material is 0.1 g / m ³ or less. The absorbent article according to claim 1, wherein the density of the above-mentioned chip wrapping material is 0.02 g / m ³ or more and 0.1 g / m ³ or less. The absorbent article according to claim 1, wherein the basis weight of the above chip-wrapped material is 5 g / m ² or more and 50 g / m ² or less.