TWI817957B - Absorbent bodies and absorbent articles - Google Patents

Abstract

The absorbent body (4) of the present invention includes fiber blocks (11) containing constituent fibers (11F) (synthetic fibers) and water-absorbent fibers (12F). The plurality of fiber blocks (11) are intertwined with each other or the fiber blocks (11) Intertwined with water-absorbent fibers (12F). The fiber block (11) has a main body (110) divided by two opposing basic planes (111) and a skeleton plane (112) intersecting the two basic planes (111). Synthetic fibers contain hydrophilizing agents. Moreover, the absorbent article (1) of this invention is provided with the absorber (4) of this invention mentioned above.

Description

Absorbent bodies and absorbent articles

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

Absorbent articles such as disposable diapers and menstrual sanitary napkins are generally composed of a front sheet placed relatively close to the wearer's skin and a front sheet placed relatively far away from the wearer's skin. The back sheet and the absorber interposed between the two sheets. Typically, the absorbent body is composed mainly of hydrophilic fibers (water-absorbent fibers) such as wood pulp and further contains water-absorbent polymer particles. For absorbers used in absorbent articles, improvement of various properties such as softness (cushioning properties), compression recovery properties, and shape retention properties is a major issue.

As an improvement technology of the absorbent body, for example, Patent Document 1 describes that in an absorbent body mainly composed of pulp fibers and water-absorbent polymers, hydrophobic fibers whose fiber length is longer than that of the pulp fibers are made, for example, without hydrophilization treatment. Synthetic fibers such as polypropylene are dispersed in the pulp fibers. According to Patent Document 1, it is believed that the absorbent body does not have the phenomenon of back seepage of body fluids due to the presence of hydrophobic fibers, and that the strength can be improved by entangling the hydrophobic fibers with longer fiber lengths with the pulp fibers, which is good. Maintain shape retention.

Furthermore, Patent Document 2 describes dispersing hydrophilic long fibers longer than pulp fibers, such as rayon, cotton, wool, linen, etc., into an absorbent body mainly composed of pulp fibers and water-absorbent polymers. within the pulp fibers. According to Patent Document 2, it is considered that the absorbent body can stably maintain its shape before and after absorbing body fluids, and since the absorbent body is obtained by dispersing the above-mentioned hydrophilic long fibers without heat treatment, the absorbent body as a whole is preferably maintained quality Sensation, less risk of obstruction of body fluid absorption.

Furthermore, Patent Document 3 describes an absorbent body containing a nonwoven fabric sheet containing thermally fusible fibers and hydrophilic fibers that are bonded to each other in advance to provide a three-dimensional structure. The nonwoven sheet with a three-dimensional structure is manufactured by crushing the nonwoven fabric into fine sheets using a crushing method such as a shredder method. Due to the above manufacturing method, an irregular shape is formed as described in Figures 1 and 3 of this document, and There is essentially no part that can be regarded as a plane. Patent Document 3 describes a preferred form of the absorbent body described in the document, in which nonwoven fabric sheets are thermally fused to each other. According to the absorbent body described in Patent Document 3, since the nonwoven fabric sheet has a three-dimensional structure, voids are formed inside the absorbent body, thereby improving recovery properties when moisture is absorbed, and as a result, water absorbing performance is improved.

Furthermore, Patent Document 4 describes a microfiber web including a relatively dense microfiber core and fibers or fiber bundles extending outward from the core. It is also described that the microfiber web can be combined with wood. A nonwoven fiber web mixed with pulp or water-absorbent polymer particles is used as an absorbent body for absorbent articles. This microfiber web is produced by plucking or pulling off a raw material sheet such as nonwoven fabric. Like the nonwoven fabric sheet described in Patent Document 3, it is formed into an unfixed shape and has substantially no portion that can be considered a plane.

Prior technical literature patent documents

Patent document 1: Japanese Patent Application Publication No. 2004-73698

Patent Document 2: Japanese Patent Application Publication No. 6-98909

Patent Document 3: Japanese Patent Application Publication No. 2002-301105

Patent Document 4: Japanese Patent Application Publication No. 1-156560

The present invention relates to an absorbent body including a fiber block containing synthetic fiber and water-absorbent fiber, and a plurality of the fiber blocks are intertwined with each other or the fiber block and the water-absorbent fiber are intertwined with each other. The fiber block has a main body divided by two opposing basic planes and a skeleton plane intersecting the two basic planes. The above-mentioned synthetic fiber contains a hydrophilizing agent.

Furthermore, the present invention relates to an absorbent article provided with the absorbent core of the present invention.

1: sanitary napkin

2: Front sheet

3: Back sheet

4:Absorbent body

5:Absorbent body

5W: Wing

6: Side sheet

10bs: raw fiber sheet

11: Fiber block

11A: Fiber block

11B: Fiber block

11F: Constituent fiber

11Z: Overlapping parts of multiple fiber blocks

12F: water-absorbent fiber

40:Absorbent core

41: chip-coated material

110: Ontology Department

111:Fundamentals

111a: short side

111b: long side

112:Skeleton surface

113: Extension fiber part

113S: Extended fiber bundle part

A:Front area

B: Longitudinal central area

BL: junction

C: Rear area

D1: 1st direction

D2: 2nd direction

F: external force

L1:Length

L1a: interval

L2: length

L2a: interval

T:Thickness

X: portrait

Y: Horizontal

Z:Thickness direction

FIG. 1 is a partially broken plan view schematically illustrating the skin-facing side (front sheet side) of a menstrual napkin as one embodiment of the absorbent article of the present invention.

FIG. 2 is a cross-sectional view schematically showing a section along the line I-I in FIG. 1 .

FIG. 3 is a schematic perspective view of a part of the absorbent core included 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 during compression.

5(a) and 5(b) are respectively schematic perspective views of the main body part in the fiber block of the present invention.

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

Figure 7(a) is an electron micrograph of an example of the fiber block of the present invention (observation magnification: 25 times), and Figure 7(b) is an electron micrograph of the fiber block as the fiber contained in the absorber shown in Figure 2. A diagram represented schematically by blocks.

The absorbers described in Patent Documents 1 and 2 both contain not only cellulosic fibers such as pulp fibers but also hydrophilic long fibers such as synthetic fibers or rayon, and therefore have higher rigidity than those containing only cellulosic fibers. As cellulosic fibers constitute the fiber absorber, improvements in various properties such as cushioning and compression recovery properties can be expected. However, the plurality of synthetic fibers contained exist independently and do not form a lump that is gathered together. The improvement effect of these various properties is not sufficient, so when used in absorbent articles, there is a risk of wrinkles easily and insufficient fit, especially after absorbing body fluids such as urine and menstrual blood. The occurrence of adverse situations is more obvious.

On the other hand, the absorbent cores described in Patent Documents 3 and 4 are both expected to have improved cushioning properties because the synthetic fibers they contain are synthetic fiber aggregates called nonwoven fabric sheets, microfiber webs, or the like. However, as mentioned above, the synthetic fiber aggregate contained in the absorbent cores described in Patent Documents 3 and 4 is produced by crushing nonwoven fabrics mainly composed of synthetic fibers into fine sheets, or by pulling or tearing them off, as mentioned above. Therefore, the shape is not fixed and the shape and size are inconsistent. Therefore, when mixed with pulp fibers, etc., it may be difficult to obtain a uniform mixture of the two, and the desired effect may not be obtained. Furthermore, if all the synthetic fiber aggregates contained in the absorber are thermally fused to each other like the preferred form of the absorber described in Patent Document 3, their own movement will be restricted, resulting in an increase in the hardness of the entire absorber. Various properties such as flexibility may be reduced.

Therefore, the present invention relates to an absorbent body and an absorbent article using the absorbent body. The absorbent system has excellent cushioning properties and compression recovery properties, has good response to external forces, and can be flexibly deformed, so that it is suitable for use in absorbent articles. It can improve the wearing feeling when the situation arises.

Hereinafter, preferred embodiments based on the absorbent core of the present invention and the absorbent article of the present invention equipped with the same will be described with reference to the drawings. In FIGS. 1 and 2 , a menstrual napkin 1 is shown as one embodiment of the absorbent article of the present invention. The sanitary napkin 1 is provided with an absorbent body 4 that absorbs and retains body fluids, a liquid-permeable front sheet 2 disposed on the skin-facing side of the absorbent body 4 so as to be in contact with the wearer's skin, and a liquid-permeable front sheet 2 disposed on the absorbent body 4 Liquid-impermeable back sheet 3 on the side not facing the skin. As shown in Figure 1, sanitary napkin 1 has The longitudinal direction The longitudinal center area B of the excretory-opposing part (excretion point) facing the excretory part such as the vulva is arranged in the area A in front of the wearer's ventral side (front side) than the excretory-opposing part, and is arranged in There are a total of three areas C located behind the wearer's back (rear side) from the excretory part-facing part.

In this specification, the "skin-facing surface" refers to the surface of the absorbent article or its component (for example, the absorbent body 4) that faces the wearer's skin when the absorbent article is worn, that is, is opposite to the wearer's skin. The closer side, the "non-skin-facing side" is the side of the absorbent article or its constituent members that faces opposite to the skin side when the absorbent article is worn, that is, the side that is relatively far from the wearer's skin. . In addition, the term "when worn" here refers to a state in which the normal appropriate wearing position, that is, the correct wearing position of the absorbent article is maintained.

As shown in Figure 1, the sanitary napkin 1 has an absorbent body 5 that is long in the longitudinal direction X, and both sides of the longitudinal central region B in the absorbent body 5 along the longitudinal direction A pair of wings 5W and 5W extend from the outside. The absorbent main body 5 forms the main body of the sanitary napkin 1 and includes the front sheet 2, the back sheet 3 and the absorbent body 4, and is divided into a front area A, a longitudinal center area B and a rear area C in the longitudinal direction X. 3 areas.

Furthermore, the vertical center region in the absorbent article of the present invention, when the absorbent article like sanitary napkin 1 has wings, means that it has a region in the longitudinal direction (length direction, X direction in the figure) of the absorbent article. The area of the wing, taking the sanitary napkin 1 as an example, is the area sandwiched between the root of one wing 5W along the longitudinal direction X and the root of the other wing 5W along the longitudinal direction X. In addition, the longitudinal center region in an absorbent article without wings refers to the region located in the middle when the absorbent article is divided into three equal parts in the longitudinal direction.

In the sanitary napkin 1, the absorbent body 4 is a liquid-absorbent absorbent core. 40, and a liquid-permeable coating sheet 41 covering the outer surface of the absorbent core 40. Like the absorbent body 5, the absorbent core 40 has a long shape in the longitudinal direction X when viewed from above as shown in Figure 1. The length direction of the absorbent core 40 is consistent with the longitudinal direction The width direction of the sexual core body 40 is consistent with the transverse direction Y of the sanitary napkin 1 . The absorbent core 40 and the covering core material 41 may be joined by an adhesive such as a hot-melt adhesive. Furthermore, the absorbent body 4 may not include the covering sheet 41. In this case, the absorbent core 40 can be directly used as the absorbent body 4 in absorbent articles.

In this way, the absorbent body 4 as one embodiment of the absorbent body of the present invention comes into indirect contact with human skin by being incorporated into an absorbent article such as the sanitary napkin 1, that is, it is indirectly in contact with the human skin through members such as the front sheet 2. When worn against the skin, it has a skin-facing surface and a non-skin-facing surface on the opposite side, a longitudinal direction In the longitudinal direction X, it is divided into three areas: front area A, vertical center area B, and rear area C. Furthermore, in addition to such indirect contact with human skin, the absorbent body 4 can also be used in direct contact.

In the sanitary napkin 1, the covering sheet 41 is a continuous sheet having a width of not less than 2 times and not more than 3 times the length of the transverse direction Y of the absorbent core 40, as shown in Figure 2, covering the absorbent core. 40, and extends from both sides of the absorbent core 40 along the longitudinal direction X to the outside in the transverse direction Y, and the extended portion is rolled down to the bottom of the absorbent core 40, Covers the entire area of the absorbent core 40 that is not facing the skin. Furthermore, in the present invention, the core-covering chip material may not be such a single sheet. For example, it may be constituted by a skin-side coating chip covering the skin-facing surface of the absorbent core 40 A total of two pieces of non-skin side wrapping core material, and one piece of non-skin side wrapping core material that covers the non-skin facing surface of the absorbent core 40 separately from the skin side wrapping core material.

As shown in Figure 2, the front sheet 2 covers the entire skin-facing surface of the absorbent body 4. area. On the other hand, the back sheet 3 covers the entire area of the non-skin facing surface of the absorbent body 4, and extends from both edges of the absorbent body 4 along the longitudinal direction Materials 6 together form side wings. The above-mentioned side flap portion is a portion of the sanitary napkin 1 including a member extending outward from the absorbent body 4 in the transverse direction Y. The back sheet 3 and the side sheets 6 are joined to each other at the extension portions from both sides of the absorber 4 along the longitudinal direction X by known joining means such as adhesive, heat sealing, and 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 conventionally used for absorbent articles such as menstrual napkins can be used without particular limitation. For example, as the front sheet 2, a single-layer or multi-layer nonwoven fabric, a perforated film, or the like can be used. As the back sheet 3, a moisture-permeable resin film or the like can be used.

As shown in FIG. 1 , the side flaps protrude greatly outside the longitudinal center region B in the transverse direction Y. Thereby, a pair of flaps 5W, 5W are extended on both left and right sides of the absorbent body 5 along the longitudinal direction X. In the plan view shown in Figure 1, the wing portion 5W has a substantially trapezoidal shape with the lower bottom (the side longer than the upper bottom) located on the side of the absorbent body 5. On its non-skin facing surface, a wing is formed. The part 5W is fixed to the wing adhesive part (not shown) of clothing such as shorts. The wing portion 5W is used by being folded back toward the non-skin facing surface (outer surface) of the crotch portion of clothing such as shorts. The above-mentioned wing adhesive portion is covered with a release sheet (not shown) including film, non-woven fabric, paper, etc. before use. Furthermore, on both sides of the skin-facing surface of the absorbent main body 5 , that is, the skin-facing surface of the front sheet 2 along the longitudinal direction It is arranged over substantially the entire length of the absorbent main body 5 in the longitudinal direction X so that the left and right sides along the longitudinal direction X overlap. The pair of side sheets 6 and 6 are respectively joined to other members such as the front sheet 2 by known joining means such as adhesives at joining lines (not shown) extending in the longitudinal direction X.

As one of the main characteristic parts of the sanitary napkin 1, the absorbent body 4, especially It is the absorbent core 40 which forms the main body of the absorbent body 4. In Figure 3, a portion of the absorbent core 40 is shown. As shown in FIGS. 2 and 3 , the absorbent body 4 , more specifically, the absorbent core 40 includes a fiber block 11 including a plurality of constituent fibers 11F (synthetic fibers), and water-absorbent fibers 12F. The fiber block 11 is a fiber assembly in which the constituent fibers 11F are intentionally gathered and integrated. In contrast, the water-absorbent fibers 12F are not intentionally integrated and exist in the absorbent state in a state that they can exist independently. Sexual core body 40. The fiber block 11 mainly contributes to improving the softness, cushioning properties, compression recovery properties, shape retention, etc. of the absorbent core 40 . On the other hand, the water-absorbent fiber 12F mainly contributes to the improvement of liquid absorbency, shape retention, etc. of the absorbent core 40 . In addition, the absorptive core 40 can actually be called the absorber 4 itself. The following description of the absorptive core 40 shall be appropriately applied to the description of the absorber 4 unless otherwise specified. That is, in the present invention, the absorbent body does not include a covering sheet but is formed only of the absorbent core. In this case, the absorbent body and the absorbent core system have the same meaning.

The so-called "fiber block" in this specification refers to a fiber assembly in which a plurality of fibers are gathered into one body. Examples of the form of the fiber block include sheet pieces of a certain size divided from a synthetic fiber sheet. In particular, it is preferable to select a nonwoven fabric as the synthetic fiber sheet and cut a nonwoven fabric piece of a specific size and shape from the nonwoven fabric as a fiber block.

In this way, the sheet-shaped fiber block, which is a preferred embodiment of the fiber block of the present invention, is not formed by aggregating a plurality of fibers to form the sheet, but is formed by a fiber block having a size larger than the sheet. Manufacturer of cutting fiber sheets (preferably non-woven fabrics) (see Figure 6). The plurality of fiber blocks contained in the absorbent body (absorbent core) of the present invention are sheet-like fiber blocks with higher shapeability than those produced by the prior art such as Patent Documents 3 and 4.

It is preferable that 90 mass % or more of the constituent fibers 11F of the fiber block 11 are synthetic fibers, and more preferably 100 mass %, that is, all the constituent fibers 11F are synthetic fibers. Also, as mentioned below, Furthermore, it is preferable that the constituent fiber 11F which is a synthetic fiber is non-water absorbent.

In the absorbent core 40, a plurality of fiber blocks 11 are intertwined with each other, or the fiber blocks 11 and the water-absorbent fibers 12F are intertwined. In the absorbent core 40 of this embodiment, the plurality of fiber blocks 11 are combined to form one fiber block continuous body by being entangled with the constituent fibers 11F and the water-absorbent fibers 12F in the absorbent core 40 . Moreover, a plurality of fiber blocks 11 may be entangled with each other, and the fiber blocks 11 and the water-absorbent fibers 12F may be entangled and combined. Furthermore, a plurality of water-absorbent fibers 12F are usually entangled with each other. At least part of the plurality of fiber blocks 11 included in the absorbent core 40 is entangled with other fiber blocks 11 or water-absorbent fibers 12F. In the absorbent core 40, the plurality of fiber blocks 11 contained in the absorbent core 40 may all be intertwined with each other to form one fiber block continuum, or the plurality of fiber block continuums may be mixed with each other in a non-combined state. situation.

Since the fiber block 11 itself is excellent in flexibility and the like, by being contained in an absorbent body (absorbent core), the absorbent body becomes potentially excellent in flexibility and the like. Since the absorbent core 40 contains such fiber blocks 11, and the fiber blocks 11 or the fiber blocks 11 and the water-absorbent fibers 12F are bonded to each other through entanglement, the absorbent core 40 is less resistant to external forces. The responsiveness is even better, and the shape retention, softness, cushioning, and compression recovery properties are excellent. For example, when the sanitary napkin 1 is worn, the absorbent core 40 can flexibly deform in response to external forces (such as the wearer's body pressure) from various directions, and has good conformability and close contact with the wearer's body.

In FIG. 4 , the deformation state when the absorbent core 40 is compressed upon receiving an external force F is schematically shown. In the absorbent core 40 in which the fiber block 11 as a fiber assembly and the water-absorbent fiber 12F as a non-fiber assembly are mixed, due to the difference in rigidity between the two members 11 and 12F, the boundary BL between the two members 11 and 12F (dashed line in FIG. 4 ) is particularly prone to deflection, and the boundary BL functions as a deflection portion when the absorbent core 40 is deformed. This boundary BL as a deflection portion usually exists throughout the entire area of the absorbent core 40 , so the absorbent core 40 responds to various external forces It has good elasticity and is flexible to deform, and when the external force is removed, it can quickly return to its original state due to the compression recovery property of the fiber block 11. The deformation-recovery characteristics of the absorbent core 40 are not only exhibited when the absorbent core 40 is compressed, but also can be similarly exhibited when the absorbent core 40 is twisted. That is, the absorbent core 40 incorporated in the sanitary napkin 1 is disposed in a state of being sandwiched between the wearer's thighs when the sanitary napkin 1 is worn. Therefore, there is a possibility that the absorbent core 40 may be affected by the wearer's walking motion. When the two thighs move and twist around an imaginary axis of rotation extending in the longitudinal direction The sanitary napkin 1 can be easily deformed and recovered from forces other than the twisting of the two thighs, so it is not easy to wrinkle, and the sanitary napkin 1 can be provided with a high conformability to the wearer's body.

As described above, in the absorbent core 40, the fiber blocks 11 are intertwined with each other or the fiber blocks 11 and the water-absorbent fibers 12F are intertwined. Here, the so-called "interaction" of the fiber blocks 11 with each other includes the following forms A and B. .

Form A: A form in which the fiber blocks 11 are combined not by fusing but by entangling the constituent fibers 11F of the fiber block 11 with each other.

Form B: In the natural state of the absorbent core 40 (a state in which no external force is applied), the fiber blocks 11 are not combined with each other, but in a state in which an external force is applied to the absorbent core 40, the fiber blocks 11 can be connected to each other by The fibers 11F are entangled and combined with each other. The "state in which an external force is applied to the absorbent core 40" here refers to, for example, a state in which a deformation force is applied to the absorbent core 40 during wearing of an absorbent article to which the absorbent core 40 is applied.

In this way, in the absorbent core 40, like the form A, the fiber block 11 and the other fiber blocks 11 or the water-absorbent fibers 12F are combined by the mutual entanglement of the fibers, that is, "intersection". In addition, like the form B, It also exists in a state of being intertwined with other fiber blocks 11 or water-absorbent fibers 12F. The combination achieved by the intertwining of fibers becomes a more effective way to express the above-mentioned absorption. The effect of the sex core 40 is one of the more important aspects. However, in terms of shape retention, the absorbent core 40 preferably has the "intersection" of Form A. The bonding by the entanglement of fibers is not formed by bonding or fusing using a bonding component, but is formed only by the entanglement of fibers with each other. Therefore, it is compared with the "fusion of fibers" as described in Patent Document 3, for example. The achieved combination and intertwined elements (fiber block 11, water-absorbent fiber 12F) have a higher degree of freedom of movement, so that each element can move within a range that maintains the integrity of the aggregate including them. In this way, the absorptive core 40 has a loose shape retention property that can be deformed when subjected to external force due to the relatively loose combination of the plurality of fiber blocks 11 contained therein with each other or the fiber blocks 11 and the water-absorbent fibers 12F. And it takes into account the shape retention, cushioning and compression recovery properties at a higher level.

It is not necessary that all the bonding modes through the fiber blocks 11 in the absorbent core 40 are "interlaced". A part of the absorbent core 40 may also include other bonding modes other than interlacing, such as bonding by an adhesive. wait.

However, the absorbent core 40 is formed by integrating it with other components of the absorbent article such as the above-mentioned leakage prevention grooves, and the remaining portion is eliminated from the absorbent core 40 by "fusion through the fiber block 11" and is formed in the absorbent core 40. The core body 40 itself is preferably formed by only "interaction of fibers" where the fiber blocks 11 are bonded together or the fiber blocks 11 and the water-absorbent fibers 12F are bonded together.

From the perspective of making the effect of the above-mentioned absorbent core 40 appear more reliably, the "fiber block 11 bonded by entanglement" as the form A and the "fiber block 11 in a state that can be intertwined" as the form B ” is preferably more than half, more preferably more than 70%, and more preferably more than 80% of the total number of fiber blocks 11 in the absorbent core 40.

From the same point of view, the number of fiber blocks 11 having "interactions" of form A is preferably at least 70% of the total number of fiber blocks 11 having joints with other fiber blocks 11 or water-absorbent fibers 12F, and is particularly preferred. is more than 80%.

As one of the main features of the absorbent core 40, the outer shape of the fiber block 11 can be cited. In FIG. 5 , two typical outer shapes of fiber blocks 11 are shown. The fiber block 11A shown in FIG. 5(a) has a square prism 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 are common in having two opposing base planes 111 and a body plane 112 connecting the two base planes 111 . Both the basic surface 111 and the skeleton surface 112 are portions that are confirmed to be substantially free of unevenness at the level applied when evaluating the degree of unevenness of the surface of an article mainly composed of such fibers.

The rectangular parallelepiped fiber block 11A shown in Figure 5(a) has six flat surfaces. Among the six flat surfaces, the two opposite surfaces with the largest areas are respectively the basic surfaces 111, and the remaining four surfaces are respectively the skeleton surfaces 112. The basic plane 111 and the skeleton plane 112 intersect each other, more specifically, are orthogonal to each other.

The disc-shaped fiber block 11B in Figure 5(b) has two opposite flat surfaces in a circular shape when viewed from above, and a curved peripheral surface connecting the two flat surfaces. The two flat surfaces are respectively the basic surface 111. The peripheral surface is the skeleton surface 112.

The fiber blocks 11A and 11B are also similar in that the skeleton surface 112 has a quadrangular shape in plan view, more specifically, a rectangular shape.

The difference between the plurality of fiber blocks 11 included in the absorbent core 40 and the nonwoven fabric sheets or microfiber webs described in Patent Documents 3 and 4, which are fiber aggregates with an indefinite shape, is that the plurality of fiber blocks 11 are respectively As shown in FIG. 5 , the fiber blocks 11A and 11B are "fixed-shaped fiber aggregates" having two opposing basic surfaces 111 and a skeleton surface 112 connecting the two basic surfaces 111 . In other words, when any one fiber block 11 in the absorbent core 40 is seen through (for example, when observed through an electron microscope), the see-through shape of the fiber block 11 is different depending on the viewing angle. Each fiber block 11 There are multiple perspective shapes, and the plurality of fiber blocks 11 in the absorbent core 40 each have two opposing basic surfaces 111 and a skeleton connecting the two basic surfaces 111 The specific perspective shape of surface 112 is one of its multiple perspective shapes. The plurality of nonwoven fabric sheets or microfiber webs contained in the absorbent cores described in Patent Documents 3 and 4 do not substantially have "surfaces" such as the basic surface 111 or the skeleton surface 112, that is, there are extended parts, and the outer shapes are different from each other. "Fixed shape".

If the plurality of fiber blocks 11 included in the absorbent core 40 are "fixed-shaped fiber aggregates" divided by the basic surface 111 and the skeleton surface 112, compared with those described in Patent Documents 3 and 4 In the case of a fiber aggregate with an irregular shape, the uniform dispersion of the fiber blocks 11 in the absorbent core 40 is improved. Therefore, by blending the fiber aggregate such as the fiber blocks 11 in the absorbent core 40, the expected effect is achieved (The effect of improving the softness, cushioning properties, compression recovery properties, etc. of the absorbent core) appears stably. Moreover, especially in the case of the rectangular parallelepiped-shaped fiber block 11 as shown in Figure 5(a), since its outer surface includes a total of 6 surfaces, including 2 basic surfaces 111 and 4 skeleton surfaces 112, compared with The disc-shaped fiber block 11 with three outer surfaces shown in Figure 5(b) has relatively more contact opportunities with other fiber blocks 11 or water-absorbent fibers 12F, and the intertwining properties are improved, and it can also bring To improve shape retention and so on.

In the fiber block 11, it is preferable that the total area of the two basic surfaces 111 is larger than the total area of the skeleton surface 112. That is, in the rectangular parallelepiped fiber block 11A in Figure 5(a) , the sum of the areas of each of the two basic surfaces 111 is greater than the sum of the areas of each of the four skeleton surfaces 112. Also, in Figure 5(b) ) in the disc-shaped fiber block 11B, the sum of the areas of each of the two basic surfaces 111 is greater than the area of the skeleton surface 112 forming the peripheral surface of the disc-shaped fiber block 11B. In either of the fiber blocks 11A and 11B, the basic surface 111 is the surface with the largest area among the plurality of surfaces that the fiber blocks 11A and 11B have.

This kind of fiber block 11, which is a "fixed-shaped fiber assembly" divided by two basic planes 111 and a skeleton plane 112 intersecting the two basic planes 111, can be produced by changing the manufacturing method. The method is different from the previous technology. As shown in FIG. 6 , a preferred method for manufacturing the fiber block 11 is to use a cutting device such as a cutter to cut the raw fiber sheet 10bs (a sheet that has the same composition as the fiber block 11 and is larger in size than the fiber block 11 ). Those broken into a fixed shape. The shapes and sizes of the plurality of fiber blocks 11 produced in this manner are more consistently consistent than those produced by prior art techniques such as Patent Documents 3 and 4. Fig. 6 is a diagram illustrating a method of manufacturing the rectangular parallelepiped fiber block 11A shown in Fig. 5(a). The dotted line in Fig. 6 indicates a cutting line. In the absorbent core 40, a plurality of fiber blocks 11 having uniform shapes and sizes obtained by cutting the fiber sheet into a fixed shape are prepared. As mentioned above, the raw material fiber sheet 10bs is preferably a nonwoven fabric.

The rectangular parallelepiped fiber block 11A of Figure 5(a) is formed by placing the raw fiber sheet 10bs in the first direction D1 and crossing (more specifically orthogonal to) the first direction D1 as shown in Figure 6 It is produced by cutting it to a specific length in the 2-direction D2. The two directions D1 and D2 are respectively a specific direction in the plane direction of the raw fiber sheet 10bs, and the raw fiber sheet 10bs is cut along the thickness direction Z orthogonal to the plane direction. In the plurality of rectangular parallelepiped-shaped fiber blocks 11A obtained by cutting the raw fiber sheet 10bs into a so-called small square shape in this way, usually the cut surface is the cutter when cutting the raw fiber sheet 10bs. The surface in contact with the cutting device is the skeleton surface 112, and the non-cutting surface, that is, the surface not in contact with the cutting device, is the basic surface 111. The basic surface 111 is the front and back surface (the surface perpendicular to the thickness direction Z) of the raw fiber sheet 10bs, and, as mentioned above, is the surface with the largest area among the plurality of surfaces of the fiber block 11A.

Furthermore, the above description about the fiber block 11A is also basically consistent with the disk-shaped fiber block 11B in Figure 5(b). The only substantial difference from the fiber block 11A is the cutting pattern of the raw fiber sheet 10bs. When cutting the raw fiber sheet 10bs into a fixed shape to obtain the fiber block 11B, it is only necessary to cut the raw material according to the top view shape of the fiber block 11B. The fiber sheet 10bs may be cut into a circular shape.

In addition, the outer shape of the fiber block 11 is not limited to that shown in Figure 5. Either the basic surface 111 or the skeleton surface 112 can be an uncurved flat surface like the respective surfaces 111 and 112 in Figure 5(a), or It may also be a curved surface like the skeleton surface 112 (the peripheral surface of the disc-shaped fiber block 11B) in FIG. 5(b). 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 also be a cube shape.

As described above, the two types of surfaces (the basic surface 111 and the skeleton surface 112) of the fiber block 11 (11A, 11B) are classified into two types. When manufacturing the fiber block 11, the raw fiber sheet is cut using a cutting device such as a cutter. The cut surface (skeleton surface 112) formed by 10bs, and the non-cut surface (basic surface 111) that is an original surface of the raw fiber sheet 10bs and is not in contact with the cutting device. Furthermore, depending on whether the cut surface is a cut surface, the skeleton surface 112 as a cut surface has the characteristic that the number of fiber ends per unit area is larger than that of the basic surface 111 as a non-cut surface. The "fiber end" here refers to the longitudinal end of the fiber 11F constituting the fiber block 11 . Usually, fiber ends also exist on the basic surface 111 which is a non-cut surface. However, since the skeleton surface 112 is a cut surface formed by cutting the raw fiber sheet 10bs, it includes the ends formed by the cutting. Most of the fiber ends constituting the cut ends of the fibers 11F are present on the entire skeleton surface 112. That is, the number of fiber ends per unit area of the skeleton surface 112 is greater than the number of fiber ends per unit area of the basic surface 111. quantity.

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 water-absorbent fibers 12F included in the absorbent core 40. . In addition, generally speaking, the greater the number of fiber ends per unit area, the more the entanglement can be improved, thereby improving various properties such as the shape retention of the absorbent core 40. Moreover, as mentioned above, the number of fiber ends per unit area in each surface of the fiber block 11 is not uniform, because with respect to the number of fiber ends per unit area, "skeleton surface 112>basic The size relationship of this surface 111" is established, so the intertwining properties with other fibers (other fiber blocks 11, water-absorbent fibers 12F) through the fiber block 11 vary depending on the surface of the fiber block 11, and the intertwining properties of the skeleton surface 112 are higher than Fundamentals 111. That is, the bonding force achieved through the intersection with other fibers through the skeleton surface 112 is stronger than the bonding through the intersection with other fibers through the basic surface 111. In one fiber block 11, in There may be a difference in bonding strength between the basic surface 111 and the skeleton surface 112 with other fibers.

In this way, the plurality of fiber blocks 11 contained in the absorbent core 40 have two kinds of binding forces and are intertwined with other fibers (other fiber blocks 11 and water-absorbent fibers 12F) around them. , the absorbent core 40 has both moderate softness and strength (shape retention). Moreover, when the absorbent core 40 with excellent characteristics is conventionally used as the absorbent body of an absorbent article, it can provide the wearer of the absorbent article with a comfortable wearing feeling and effectively prevent wear-related injuries. This is an undesirable situation in which the absorbent core 40 is damaged by external forces such as the wearer's body pressure.

In particular, the fiber block 11 (11A, 11B) shown in FIG. 5 has the total area of the two basic surfaces 111 larger than the total area of the skeleton surface 112 as described above. Therefore, the number of fiber ends per unit area is relatively small, which means that the total area of the basic plane 111 with relatively low intertwining with other fibers is larger than the skeleton plane 112 with the opposite property. Therefore, the fiber block 11 (11A, 11B) shown in FIG. 5 can more easily intersect with other surrounding fibers (other fiber blocks 11, water-absorbent fiber 12F) than a fiber block in which fiber ends are uniformly distributed over the entire surface. is suppressed, and even if it intersects with other surrounding fibers, it is easy to intertwine with relatively weak binding force. Therefore, it is difficult to become a large block, and excellent softness can be imparted to the absorbent core 40.

In contrast, the nonwoven fabric sheets or microfiber webs described in Patent Documents 3 and 4 are produced by cutting the raw fiber sheet into an unfixed shape by a cutting machine such as a milling cutter as described above. It is manufactured, so it does not become a sheet-shaped fiber block with a fixed shape such as the "surface" of the basic surface 111 or the skeleton surface 112, and because during the manufacturing, a force external to the cutting process is applied to the entire fiber block, so it is constituted The fiber ends of the fibers are randomly formed in the entire fiber block, and it is difficult to fully express the above-mentioned effects achieved by the fiber ends.

From the viewpoint of making the effects achieved by the above-mentioned fiber ends appear more reliably, the number N ₁ of the fiber ends per unit area of the basic surface 111 (non-cut surface) and the skeleton surface 112 (cut surface) ), the ratio of the number N ₂ of fiber ends per unit area is based on the premise that N ₁ <N _2. In terms of N ₁ /N ₂ , it is preferably 0 or more, further preferably 0.05 or more, and more preferably 0.90 or less. , and more preferably 0.60 or less. More specifically, N ₁ /N ₂ is preferably 0 or more and 0.90 or less, and further preferably 0.05 or more and 0.60 or less.

The number N ₁ of fiber ends per unit area of the basic surface 111 is preferably 0/mm ² or more, more preferably 3/mm ² or more, and more preferably 8/mm ² or less, still more preferably The best number is less than 6/ ^mm2 .

The number N ₂ of fiber ends per unit area of the skeleton surface 112 is preferably 5/mm ² or more, more preferably 8/mm ² or more, and more preferably 50/mm 2 or less, and further preferably 50/mm ² or less. The best number is less than 40 pieces/ ^mm2 .

The number of fiber ends per unit area of the basic surface 111 and the skeleton surface 112 is measured by the following method.

<Method for measuring the number of fiber ends per unit area on each side of the fiber block>

The measurement piece was attached to the sample stand using double-sided paper tape (NICETACK NW-15 manufactured by Michibon Co., Ltd.) for the member (fiber block) containing fibers to be measured. Next, the measurement piece was coated with platinum. For coating, use the product manufactured by Hitachi Naka Seiki Co., Ltd. The sub-sputtering device E-1030 (trade name) was used, and the sputtering time was set to 120 seconds. For the cut surface of the measurement piece, a JCM-6000 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 1.2mm long and 0.6mm wide at any position on the measurement object surface (basic plane or skeleton surface), and the area of this rectangular area occupies the area of the observation screen. Adjust the observation angle to more than 90%, and then measure the number of fiber ends contained in the rectangular area. However, in the 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 above rectangular area accounts for less than 90% of the entire observation screen, the observation magnification is set to greater than 100 times, and then measure the number of fiber ends included in the rectangular area of the measurement object surface in the same manner as above. Here, the "fiber ends" that are the object of the number measurement are the longitudinal ends of the constituent fibers of the fiber block, that is, the portion of the constituent fibers other than the longitudinal ends (the longitudinal middle portion) is from the measurement target surface. Extended, the middle part in the length direction will not be the object of quantity measurement. Next, the number of fiber ends per unit area in the measurement target surface (basic surface or skeleton surface) of the fiber block is calculated from the following formula. For 10 fiber blocks, measure the number of fiber ends per unit area in each of the basic plane and the skeleton plane in accordance with the above-mentioned procedure, and set the average value of the plurality of measured values in the measurement target plane. The number of fiber ends per unit area.

The number of fiber ends per unit area (number/mm ² ) in the measurement object surface (basic surface or skeleton surface) of the fiber block = the number of fiber ends contained in the rectangular area (1.2×0.6mm) /The area of the rectangular area (0.72mm ² )

When the basic surface 111 of the fiber block 11 is rectangular in plan view like the fiber block 11A shown in FIG. 5(a) , from the viewpoint of improving the uniform dispersion of the fiber block 11 in the absorbent core 40 Specifically, the short side 111a of the rectangle preferably contains the fiber block 11 (11A) The thickness of the absorbent core 40 is short.

The ratio of the length of the short side 111a to the thickness of the absorbent core 40 (former/later) is preferably 0.03 or more, more preferably 0.08 or more, and more preferably 1 or less, further preferably 0.5 or less.

The thickness of the absorbent core 40 is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 10 mm or less, further preferably 6 mm or less. The thickness of the absorbent core 40 is measured by the following method.

<Measurement method of thickness of absorbent body (absorbent core)>

The object to be measured (absorbent body, absorbent core) is placed on a horizontal place without wrinkles or bends, and the thickness of the object to be measured is measured under a load of 5 cN/ ^cm2 . Specifically, for thickness measurement, for example, thickness gauge PEACOCK DIAL UPRIGHT GAUGES R5-C (manufactured by OZAKI MFG. Co. LTD.) is used. At this time, a circular or square flat plate (thickness 5 mm) whose size has been adjusted in plan view is placed between the front end of the thickness gauge and the cut out object to be measured so that the load on the object to be measured becomes 5 cN/cm ² (left and right acrylic resin sheets), and measure the thickness. Thickness measurement is performed by measuring 10 points and calculating the average value as the thickness of the object to be measured.

The dimensions of each part of the fiber block 11 (11A, 11B) are preferably set as follows. The dimensions of each part of the fiber block 11 can be measured based on electron micrographs and the like during specific operations of the outer shape of the fiber block 11 described below.

When the basic surface 111 has a rectangular shape in plan view as shown in FIG. 5(a) , the length L1 of the short side 111a is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. Furthermore, it is preferably 10 mm or less, further preferably 6 mm or less, and particularly preferably 5 mm or less.

The length L2 of the long side 111b of the rectangular basic surface 111 when viewed from above is preferably 0.3 mm or more, more preferably 1 mm or more, especially 2 mm or more, and more preferably 30 mm or less, further preferably 15 mm or less, especially The best is less than 10mm.

Furthermore, when the basic surface 111 is the surface with the largest area among the plurality of surfaces of the fiber block 11 as shown in FIG. 5, the length L2 of the long side 111b is consistent with the maximum diameter length of the fiber block 11, The maximum diameter length is consistent with the diameter of the circular basic surface 111 in plan view in the disc-shaped fiber block 11B.

The ratio of the length L1 of the short side 111a to the length L2 of the long side 111b is preferably 0.003 or more, more preferably 0.025 or more, and is preferably 1 or less, further preferably 0.5 or less in terms of the former L1/the latter L2. 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) , and may also be a square shape, that is, the ratio of the lengths L1 and L2 of the two mutually orthogonal sides. It can also be 1 in terms of L1/L2.

The thickness T of the fiber block 11, that is, the length between two opposing basic surfaces 111, is preferably 0.1 mm or more, more preferably 0.3 mm or more, and is preferably 10 mm or less, further preferably 6 mm or less.

In addition, the absorbent core 40 is preferable because the fiber blocks 11 are distributed at high density and evenly throughout the entire absorbent core 40, making the response to external force isotropic. From this point of view, in a projection view of the absorbent core 40 in two mutually orthogonal directions, it is preferable that there are overlapping portions of a plurality of fiber blocks 11 in any unit area of 10 mm square. Symbol 11Z in FIGS. 3 and 4 represents an overlapping portion of a plurality of fiber blocks 11. As the so-called "projection views in two mutually orthogonal directions", typically, a projection view in the thickness direction of the absorbent core (i.e., from the skin-facing surface or non-skin-facing surface of the absorbent core) can be used. The absorbent core is viewed from the front) and the projection view in the direction orthogonal to the thickness direction (i.e., the self-absorbent core The absorbent core is viewed from the side of the body).

FIG. 7(a) shows an electron micrograph of an example of the fiber block of the present invention, and FIG. 7(b) shows a diagram schematically showing the fiber block 11 combined with the electron micrograph. The plurality of fiber blocks 11 included in the absorbent core 40 may include those having a main body part 110 and an extended fiber part 113 as shown in FIG. 7 . The extended fiber part 113 includes fibers extending from the main body part 110 to The constituent fibers 11F extending from the outside are formed and have a lower fiber density (a smaller number of fibers per unit area) than the main body portion 110 . Furthermore, the absorbent core 40 may also include the fiber block 11 without the extended fiber part 113, that is, the fiber block 11 including only the main body part 110. The extended fiber portion 113 may include one of the above-mentioned fiber end portions existing on each surface (basic surface 111, skeleton surface 112) of the fiber block 11, which is the fiber end portion outward from each surface of the fiber block 11. The extended fiber end.

The body part 110 is a part formed by dividing the two opposing basic surfaces 111 and the skeleton surface 112 connecting the two basic surfaces 111. The main body 110 is the part that forms the main body of the fiber block 11 and forms the fixed shape and outer shape of the fiber block 11. The fiber block 11 has various characteristics such as high softness, cushioning, and compression recovery to a basically greater extent. Depends on the body part 110. On the other hand, the extended fiber portion 113 mainly contributes to the improvement of the intertwining properties of the plurality of fiber blocks 11 contained in the absorbent core 40 or the intertwining properties of the fiber blocks 11 and the water-absorbent fibers 12F, and directly interacts with the absorbent core. It is related to the improvement of the shape retention of the body 40. In addition, it also affects the uniform dispersion of the fiber blocks 11 in the absorbent core 40, etc., thereby indirectly enhancing the effect achieved by the body part 110.

Compared with the extended fiber portion 113, the main body portion 110 has a higher fiber density, that is, the number of fibers per unit area is greater. In addition, generally the fiber density of the main body 110 itself is relatively uniform. The ratio of the main body part 110 to the total mass of the fiber block 11 is usually at least 40% by mass. The content is preferably 50 mass% or more, further preferably 60 mass% or more, and particularly preferably 85 mass% or more. The main body part 110 and the extended fiber part 113 can be distinguished by the specific operation of the following external shape.

The outer shape of the body portion 110 of the fiber block 11 included in the absorbent core 40 can be specified by focusing on the difference in fiber density (the number of fibers per unit area) between the fiber block 11 and its peripheral portion. ) or the type of fiber, fiber diameter, etc., confirm the "boundary" between the main body part 110 and other parts. The fiber density of the main body part 110 is higher than that of the extended fiber part 113 existing around it, and the synthetic fibers and water-absorbent fibers 12F (typically cellulose-based fibers) that are generally the constituent fibers of the main body part 110 are essentially and/or are different in size. Therefore, even in 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-mentioned aspects. The interface confirmed in this way is the peripheral edge (edge) of the basic plane 111 or the skeleton plane 112. Through this interface confirmation operation, the basic plane 111 and the skeleton plane 112 are specified, and further the main body 110 is specified. This boundary confirmation operation can be performed by using an electron microscope and observing the object (absorbent core 40) at a plurality of observation angles as necessary. In particular, when the fiber block 11 included in the absorbent core 40 is the fiber block 11A, 11B shown in FIG. 5 and the total area of the two basic surfaces 111 is larger than the total area of the skeleton surface 112, Especially when the basic surface 111 becomes the surface with the largest area of the fiber block 11, the basic surface 111 with the larger area can be identified relatively easily, so that the outer shape of the main body 110 can be smoothly determined. Specific assignments.

As shown in FIG. 7 , the extended fiber portion 113 includes the constituent fibers 11F of the body portion 110 extending outward from at least one of the basic surface 111 and the skeleton surface 112 that form the outer surface of the body portion 110 . FIG. 7 is a diagram looking down at the fiber block 11 from the side of the basic plane 111 (the plane with the largest area among the plurality of planes of the fiber block 11). A plurality of constituent fibers 11F extend from the skeleton plane 112 intersecting the basic plane 111. The extended fiber portion 113 is formed.

The shape of the extended fiber portion 113 is not particularly limited. The extended fiber portion 113 may include one constituent fiber 11F, or may include a plurality of constituent fibers 11F like the extended fiber bundle portion 113S described below. In addition, the extended fiber portion 113 includes the longitudinal end portion of the constituent fiber 11F extended from the main body portion 110. However, in some cases, it may include both ends of the constituent fiber 11F in the longitudinal direction in addition to such fiber ends. The portion (longitudinal middle portion) other than the portion (longitudinal middle portion), or the portion (longitudinal middle portion) other than the longitudinal end portions constituting the fiber 11F is included instead of including the fiber end portion. That is, in the fiber block 11, both longitudinal end portions of the constituting fiber 11F exist in the main body 110, and the other portion, that is, the longitudinal middle portion extends annularly (projects) outward from the main body 110. In this case, the extended fiber portion 113 in this case is composed of an annular protruding portion constituting the fiber 11F. In other words, the exposed end of the extended fiber portion 113 becomes one type of fiber end.

As mentioned above, one of the main tasks of the extended fiber portion 113 is to intertwine the plurality of fiber blocks 11 contained in the absorbent core 40 with each other, or to intertwine the fiber blocks 11 and the water-absorbent fibers 12F. Generally speaking, 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 included in one fiber block 11 When the number increases, the connection between the objects intertwined through the extended fiber portion 113 is strengthened and the intertwining becomes difficult to be released, so that the specific effect of the present invention can be exerted more stably.

When the fiber block 11 is obtained by cutting the raw fiber sheet 10bs into a fixed shape as shown in FIG. 6 , relatively many extended fiber portions 113 exist on the skeleton surface 112 which is the cut surface. On the other hand, they are not present at all on the basic surface 111 which is a non-cut surface, or even if they are present on the basic surface 111 , the number thereof is smaller than the number present on the skeleton surface 112 . The reason why the extended fiber portions 113 are concentrated on the skeleton surface 112 as the cut surface is because most of the extended fiber portions 113 are "fuzz" generated by cutting the raw fiber sheet. That is, through raw fiber Since the skeleton surface 112 formed by cutting the fiber sheet 10bs is entirely rubbed by a cutting device such as a cutter during the cutting, fluff including the constituent fibers 11F of the raw fiber sheet 10bs is easily formed, which is called fuzzing. On the other hand, since there is no friction between the basic surface 111 as the non-cutting surface and such a cutting device, it is difficult to form fluff, that is, the extended fiber portion 113 .

From the viewpoint of promoting the formation of the above-mentioned extended fiber portion 113 and ensuring the size required for the fiber block 11 to exhibit a specific effect, the distance between the cutting lines L1a (th) when the raw fiber sheet 10bs is cut is The distance between the first direction) and the distance L2a (the distance between the second direction) are preferably 0.3 mm or more, more preferably 0.5 mm or more, and more preferably 30 mm or less, further 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 constituent fibers 11F extending from the main body portion 110 , more specifically, the skeleton surface 112 to the outside as one of the extended fiber portions 113 . At least one of the extended fiber portions 113 included in the fiber block 11 may be the extended fiber bundle portion 113S. The extended fiber bundle portion 113S is composed of a plurality of constituent fibers 11F extending from the skeleton surface 112 and is characterized in that the extension length from the main body portion 110 (skeleton surface 112) is longer than that of the extended fiber bundle portion 113 aspect. The extended fiber bundle portion 113S may also exist on the basic surface 111. However, typically, it exists on the skeleton surface 112 as shown in FIG. 7 and does not exist on the basic surface 111 at all. The number existing on the skeleton surface 112 is small. The reason for this is the same as the reason why the extended fiber portion 113 mainly exists on the skeleton surface 112 as the cut surface, and has been described above.

Because the fiber block 11 has such a long and thick extended fiber bundle portion 113S, which should also be called a large extended fiber portion 113, the fiber blocks 11 intersect with each other or the fiber block 11 and the water-absorbent fiber 12F intersect. It is further enhanced, and as a result, the specific effect of the present invention produced by the presence of the fiber block 11 is further stably exerted. The extended fiber bundle portion 113S can be easily The raw fiber sheet 10bs can be cut easily under raised conditions (see Figure 6).

The extended length of the extended fiber bundle portion 113S from the main body portion 110, that is, the extended length from the skeleton surface 112 (cut surface) is preferably 0.2 mm or more, more preferably 0.5 mm or more, and more preferably 7mm or less, more preferably 4mm or less. The extended length of the extended fiber bundle portion 113S can be measured in the above-mentioned operation of specifying the outer shape of the fiber block 11 (interface confirmation operation). Specifically, for example, using a microscope (50 magnification) made by Keyence, a double-sided tape made by 3M Co., Ltd. is attached to the surface of a transparent sample stage made of acrylic resin, and the fiber block 11 is placed. After being fixed on it, the outer shape of the fiber block 11 is specified according to the above-mentioned outer shape specifying operation, and then the length of the extended portion of the constituent fibers 11F extending from the outer shape is measured, and the The measured length of the extended portion is set as the extended length of the extended fiber bundle portion 113S.

In the extended fiber bundle portion 113S, it is preferable that the plurality of constituent fibers 11F are thermally fused to each other. The thermally fused portion of the extended fiber bundle portion 113S is generally larger in diameter in a direction orthogonal to the length direction of the extended fiber bundle portion 113S than other portions of the extended fiber bundle portion 113S (non-thermally fused portions). (The diameter when the cross section of the thermal fusion part is circular) is longer. Since the extended fiber bundle portion 113S has such a thermal fusion portion, which can also be called a large-diameter portion, the strength of the extended fiber bundle portion 113S itself is improved, whereby the fiber blocks 11 intertwined with each other through the extended fiber bundle portion 113S The intertwining or intertwining of the fiber block 11 and the water-absorbent fiber 12F is further enhanced. In addition, if the extended fiber bundle portion 113S has a thermal fusion portion, the extended fiber bundle portion 113S itself has not only a dry state but also a wet state after absorbing moisture. The strength and shape retention are also improved. Moreover, with this advantage, when the absorbent core 40 is applied to the sanitary napkin 1, not only the absorbent core 40 is in a dry state, but also the urine or menstrual blood excreted by the wearer can be absorbed. When the body fluid is in a moist state, the effect produced by the presence of the fiber block 11 can be stably exerted. This kind of possession The extended fiber bundle portion 113S of the thermally fused portion can be formed by using the above-mentioned "constituent fibers" in the manufacturing step of the fiber block 11 as shown in FIG. The fiber sheet of the thermally fused part is produced as the raw material fiber sheet 10bs.

As described above, the fiber block 11 is characterized by having the main body portion 110 (fixed-shaped fiber assembly) divided by the basic surface 111 and the skeleton surface 112. It is also characterized by the fact that its constituent fibers 11F contain a hydrophilizing agent. aspects of synthetic fibers. In the present invention, the "hydrophiliifying agent" refers to an agent that increases the hydrophilicity of the fiber when the hydrophilizing agent is applied to the fiber, and more specifically, decreases the contact angle with water measured by the following method. .

Whether the fiber is hydrophilic or water-resistant can be determined based on the contact angle with water measured by the following method. If the contact angle with water is less than 90 degrees, it is hydrophilic, and if it is more than 90 degrees, it is water-resistant. sex. The smaller the contact angle with water measured by the following method, the higher the hydrophilicity (the lower the hydrophilicity), and the larger the contact angle, the lower the hydrophilicity (the higher the hydrophilicity).

<Measurement method of contact angle>

Fibers were taken out from the measurement object (absorbent core), and the contact angle of water with respect to the fibers was measured. An automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. was used as a measuring device. For contact angle measurements use deionized water. The amount of liquid ejected from the inkjet water droplet ejection unit (pulse jet CTC-25 with an ejection unit hole diameter of 25 μm manufactured by Cluster Technology) was set to 20 picolitres, and water droplets were added directly above the fiber. The dripping situation is recorded on a high-speed video device connected to a camera installed horizontally. From the viewpoint of subsequent image analysis, the video recording device is preferably a personal computer equipped with a high-speed capture device. In this measurement, images were recorded every 17 msec. In the recorded images, the accessory 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 non-reflection, Figure Image processing image mode is set to frame, critical level (set to 200, and set as no curvature correction), perform image analysis on the initial image of the water droplet attached to the fiber, calculate the angle between the surface of the water droplet that contacts the air and the fiber, and set it as the contact angle. The fiber taken out from the object to be measured is cut into a fiber length of 1 mm, and the fiber is placed on the sample stage of the contact angle meter and maintained horizontally. For each fiber, measure the contact angles at two different locations. The contact angle of N=5 fibers is measured to 1 decimal place, and the value obtained by averaging the measured values of a total of 10 locations (rounded to the 2nd decimal place) is defined as the contact angle between the fiber and water. . The measurement environment is set to room temperature 22±2℃ and humidity 65±2%RH.

Furthermore, when the absorbent body (absorbent core) to be measured is used as a constituent member of other articles such as absorbent articles, and the absorbent body is taken out for evaluation and measurement, the absorbent body is fixed by adhesive, fusion, etc. When constructing other components, the adhesive force is removed from the fixed part by blowing cold air with cold spray within a range that does not affect the contact angle of the fibers, and then the absorbent body is taken out. This sequence is common to all measurements in this case manual.

When the synthetic fiber constituting the fiber 11F of the fiber block 11 contains a hydrophilizing agent, it means that the fiber block 11 is subjected to hydrophilization treatment. One of the effects obtained by hydrophilizing the fiber mass 11 contained in the absorbent core 40 is an improvement in physical properties when the absorbent core 40 absorbs and retains liquid in a moist state. According to the findings of the present inventors, if the degree of hydrophilization of the constituent fibers (synthetic fibers) of the fiber block is increased (the contact angle with water is reduced), the compression workload (w) of the absorbent core containing the same in a wet state will increase. -WC) tend to increase. An increase in the value of w-WC leads to an improvement in the cushioning properties of the absorbent core in a wet state. Therefore, it can be said that the situation where the constituent fibers (synthetic fibers) of the fiber block contain a hydrophilizing agent has a significant impact on the wet state of the absorbent core. The improvement in cushioning properties is effective.

Moreover, in the absorbent core 40, as mentioned above, the fiber block 11 and the water-absorbent fiber 12F which are its constituent members are connected to each other by entanglement between the same type and between different types. Therefore, compared with the case of combining by fusion, the mobility of body fluids (liquid diffusivity in the plane direction, liquid permeability in the thickness direction) is potentially improved, and if the fiber block 11 is further hydrophilized Chemical treatment, the excellent characteristics related to the movement of these body fluids can be further improved. For example, when the absorptive core 40 initially receives the body fluid of the wearer of the sanitary napkin 1 at the excretion part-facing portion located in the center of the longitudinal central region B among its skin-facing surfaces, the body fluid can be passed through The constituent fibers 11F of the hydrophilized fiber block 11, that is, the synthetic fibers containing the hydrophilizing agent, and the water-absorbent fibers 12F intertwined with them are quickly introduced into the interior of the absorbent core 40 from the part opposite the excretion part. It diffuses rapidly in the surface direction within the absorbent core 40 and rapidly penetrates in the thickness direction toward the non-skin-facing surface side (back sheet 3 side).

Furthermore, as mentioned above, the fiber block 11 has the main body 110 divided by the basic surface 111 and the skeleton surface 112. There are usually a plurality of interfiber gaps constituting the fibers 11F on these surfaces 111 and 112. If the fiber block 11 having a plurality of inter-fiber voids on the surface is subjected to hydrophilization treatment, the body fluid existing outside the fiber block 11 (main part 110) can be introduced into the fibers through the capillary action of the inter-fiber voids. inside the block 11, as a result the liquid absorbency of the absorbent core 40 can be improved.

Furthermore, as mentioned above, the fiber block 11 has an extended fiber portion 113 extending outward from the main body portion 110. The extended fiber portion 113 may have an extension including a plurality of constituent fibers 11F extending from the main body portion 110. As long as the constituent fiber 11F of the fiber bundle portion 113S contains a hydrophilizing agent, the extended fiber bundle portion 113S will naturally also contain a hydrophilizing agent, thereby increasing the hydrophilicity, so that body fluids can move more smoothly through the extended fiber bundle portion 113S. That is, since the constituent fibers 11F of the fiber block 11 contain a hydrophilizing agent, it is expected that in addition to the effect of improving the intersection strength of the fiber blocks 11 with each other or the intersection strength of the fiber block 11 and the water-absorbent fiber 12F, the absorbent core can be expected. The effect of improving the mobility of body fluids within 40 seconds even when wearing the sanitary napkin 1 on the absorbent core 40 When external force is exerted such as body pressure, body fluids can also be quickly transferred within the absorbent core 40 .

From the viewpoint of more reliably exerting the above-mentioned effects caused by the synthetic fiber constituting the fiber 11F of the fiber block 11 containing a hydrophilizing agent, the constituting fiber 11F containing the hydrophilizing agent is preferably a hydrophilic fiber. The contact angle between fiber 11F (synthetic fiber) and water is preferably 75 degrees or less, more preferably 70 degrees or less, more preferably 60 degrees or less, and particularly preferably 50 degrees or less. The contact angle between the constituent fibers 11F and water can be adjusted by appropriately adjusting the type or content of the hydrophilizing agent contained in the constituent fibers 11F.

The constituent fiber 11F of the fiber block 11, that is, the synthetic fiber containing a hydrophilizing agent, is produced by making the raw material fiber contain a hydrophilizing agent. The contact angle between the constituent fiber 11F produced in this way and water is lower than that of the raw material fiber and water. the contact angle. The form in which the hydrophilizing agent is contained in the constituent fiber 11F is not particularly limited. Typically, the surface layer of the constituent fiber 11F is in the form of the hydrophilizing agent, that is, the hydrophilizing agent is attached to the film on the surface of the raw fiber. However, For example, instead of the above-mentioned form, a hydrophilizing agent may be mixed inside the raw fiber, or a hydrophilizing agent may be mixed inside the raw fiber and the hydrophilizing agent is adhered to the surface of the raw fiber.

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

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

Examples of the anionic surfactant in which the hydrophilic group is sulfonic acid or a salt thereof include dialkyl sulfonic acid or a salt thereof, as a preferred example showing low concentration and high permeability. Specific examples of dialkyl sulfosuccinic acid include: dioctadecylsulfosuccinic acid, didecylsulfosuccinic acid, di-tridecylsulfosuccinic acid, and di(2-ethylhexyl )Sulfosuccinic acid and other dialkyl sulfosuccinic acid, dialkyl sulfoglutaric acid and other compounds formed by esterifying dicarboxylic acid and sulfonating the α position of the diester; or 2-sulfotetradecane Acid 1-ethyl ester (or amide) sodium salt, or 2-sulfohexadecaic acid 1-ethyl ester (or amide) sodium salt, etc., change the α position of saturated fatty acid or unsaturated fatty acid ester (or amide) Alpha sulfo fatty acid alkyl esters (or amides) formed by sulfonation; or dialkyl olefin sulfonic acids obtained by sulfonating internal olefins of hydrocarbon chains or internal olefins of unsaturated fatty acids, etc. The number of carbon atoms in each of the two alkyl groups of the dialkyl sulfonic acid chain is from 4 to 14, particularly preferably from 6 to 10. Examples of the dialkyl sulfosuccinate include Pelex OT-P (product name) manufactured by Kao Co., Ltd.

Examples of the cationic surfactant include alkyl (or alkenyl) trimethylammonium halide, dialkyl (or alkenyl) dimethylammonium halide, and alkyl (or alkenyl) pyridinium. Halides, etc., these compounds are preferably those having an alkyl group or alkenyl group having a carbon number of 6 to 18. Examples of the halogen in the above-mentioned halogen compound include chlorine, bromine, and the like.

Examples of the amphoteric surfactant include alkyl (carbon number 1 to 30) dimethyl betaine, alkyl (carbon number 1 to 30) amide alkyl (carbon number 1 to 4) dimethyl Betaine, alkyl (carbon number 1~30) dihydroxyalkyl (carbon number 1~30) betaine, sulfobetaine type amphoteric interface activity Betaine-type amphoteric surfactants such as sexual agents; or alanine-type [alkyl (carbon number 1~30) aminopropionic acid type, alkyl (carbon number 1~30) iminodipropionic acid type] amphoteric interface Glycine type [alkyl (carbon number 1 to 30) aminoacetic acid type, etc.] amphoteric surfactants, amino acid type amphoteric surfactants such as alkyl betaine, alkyl (carbon number 1 to 30), etc. ) Taurine type and other aminosulfonic acid type amphoteric surfactants.

Examples of the above-mentioned nonionic surfactants include polyol fatty acid esters such as glycerin fatty acid esters, poly(preferably n=2 to 10) glycerin fatty acid esters, and sorbitan fatty acid esters (all relatively Preferably, the carbon number of the fatty acid is 8 to 60), the alkylene oxide adduct of the above-mentioned polyol fatty acid ester (preferably the molar addition number is 2 to 60 moles), polyoxyalkylene (addition Molar number 2~60) alkyl (carbon number 8~22) amide, polyoxyalkylene (addition molar number 2~60) alkyl (carbon number 8~22) ether, polyoxyalkylene Modified silicone, amine modified silicone, etc.

As the raw material fiber constituting the fiber 11F of the fiber block 11, that is, the synthetic fiber that does not contain a hydrophilizing agent, various synthetic fibers used for sanitary products can be used without particular limitation, and thermoplastic fibers are preferred. The reason why thermoplastic fibers are preferred as the constituent fibers 11F is that the fiber block 11 has a three-dimensional structure formed by thermally fusing a plurality of the constituent fibers 11F with thermoplasticity to each other, and the absorbent core 40 is in either a dry state or a wet state. All can show excellent effects in shape retention, softness, cushioning, compression recovery, and anti-wrinkle properties. Furthermore, as mentioned above, it is preferable that the extended fiber bundle portion 113S has a thermal fusion portion. Since the constituent fibers 11F of the fiber block 11 are thermoplastic fibers, a preferred form of the extended fiber bundle portion 113S can also be obtained. In order to obtain the fiber block 11 in which a plurality of thermally fused portions are three-dimensionally dispersed, the raw fiber sheet 10bs (see FIG. 6 ) may be configured in the same manner. Furthermore, as mentioned above, such a plurality of thermally fused portions are three-dimensionally dispersed. The dispersed raw fiber sheet 10bs can be produced by subjecting a fiber web or nonwoven fabric mainly composed of thermoplastic fibers to heat treatment such as hot air treatment.

Furthermore, as mentioned above, the constituent fibers 11F constituting the fiber block 11 are as in contact with water. The contact angle is preferably hydrophilic at 75 degrees or less, but it is preferably non-hydroabsorbent, that is, having the property of being difficult to absorb water (body fluids such as urine or menstrual blood). This is in marked contrast to the case where the water-absorbent fiber 12F used together with the fiber block 11 has water absorbency as stated. Since the constituent fibers 11F are non-water-absorbent fibers that lack water absorbency, the absorbent core 40 can stably exert the function of the fiber block 11 not only when it is in a dry state but also when it is in a wet state by absorbing body fluids. The effects produced by its existence (improvement of shape retention, softness, cushioning, compression recovery, resistance to wrinkles, etc.). Therefore, as the raw material fiber, non-water-absorbent synthetic fiber is preferred.

In this specification, the term "water absorbency" means, for example, that pulp is water absorbent so that it can be easily understood by those in the industry. Likewise, it can be easily understood that thermoplastic fibers are non-hydroabsorbent. On the other hand, the degree of water absorption of fibers such as synthetic fibers can also be determined by the value of the moisture content measured by the following method. As a water-absorbent fiber, the moisture content is preferably 6% or more, and more preferably 10% or more. On the other hand, the non-water-absorbent fiber preferably has a moisture content of less than 6%, and more preferably less than 4%. In addition, when the moisture content is less than 6.0%, the fibers are judged to be non-water-absorbent fibers, and when the moisture content is 6.0% or more, the fibers are judged to be water-absorbent fibers.

<Measurement method of moisture content>

The moisture content is calculated using the moisture content test method of JIS P8203. That is, after the fiber sample was left to stand for 24 hours in a test chamber with a temperature of 40° C. and a relative humidity of 80% RH, the weight W (g) of the fiber sample before absolute drying was measured in the chamber. Thereafter, the fiber sample is left to stand for 1 hour in an electric dryer (for example, manufactured by Isuzu Manufacturing Co., Ltd.) at a temperature of 105±2°C to perform absolute drying of the fiber sample. After the absolute drying process, in a standard laboratory with a temperature of 20±2°C and a relative temperature of 65±2%, use Saran Wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd. to include the fiber sample. Put Si silicone (for example, manufactured by Toyota Chemical Co., Ltd.) into the glass until it dries. In a container (for example, made by Tech jam), the fiber sample is allowed to stand until it reaches a temperature of 20 ± 2°C. Thereafter, the constant weight W' (g) of the fiber sample was weighed, and the moisture content of the fiber sample was calculated by the following formula. Moisture content (%)=(W-W'/W')×100

As the raw material fiber constituting the fiber 11F of the fiber block 11, as mentioned above, it is preferable to use a synthetic fiber made of a thermoplastic and non-water-absorbent synthetic resin. Examples of such preferred synthetic resins (thermoplastic resins) include: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, Polyalkyl methacrylate, polyvinyl chloride, polyvinylidene chloride, etc.; one of these can be used alone or two or more of them can be used in combination. Furthermore, the constituent fiber 11F may be a single fiber containing one type of synthetic resin (thermoplastic resin) or a blended polymer obtained by mixing two or more types of synthetic resins, or may be a composite fiber. The so-called composite fiber here refers to a synthetic fiber (thermoplastic fiber) obtained by combining two or more synthetic resins with different components and spinning them simultaneously through a spinning head, and a plurality of components are continuous in the length direction of the fiber. Structured in single fibers that are interconnected. The form of the composite fiber includes core-sheath type, side-by-side type, etc., and is not particularly limited.

The content of the hydrophilizing agent in the constituent fiber 11F is not particularly limited as long as it is appropriately adjusted according to the type of raw fiber or hydrophilizing agent, the desired degree of hydrophilization, etc. For example, when using the above-mentioned thermoplastic resin as a material, When the raw material fiber is used as a hydrophilizing agent generally used for sanitary products, and the contact angle between the constituent fiber 11F and water is 75 degrees or less, it is preferably 0.2 mass relative to the total mass of the constituent fiber 11F. % or more, more preferably 0.4 mass % or more, and more preferably 2.0 mass % or less, further preferably 1.5 mass % or less. If the content of the hydrophilizing agent is too small, the degree of hydrophilization of the fiber block 11 may become low and the above-mentioned effects may not be fully exerted. On the other hand, if it is too large, the transportation of the raw fiber sheet at the manufacturing site of the fiber block 11 may be problematic. The risk of contamination in the production line at this time.

On the other hand, as the water-absorbent fibers 12F used together with the fiber block 11, hydrophilic and water-absorbent fibers that have been used as a material for forming the absorbent core of such absorbent articles can be used. For example, conifer pulp or Natural fibers such as wood pulp such as hardwood pulp, non-wood pulp such as cotton pulp or hemp pulp; modified pulp such as cationized pulp and mercerized pulp; regenerated fibers such as cupro fiber, rayon, etc.; one of these can be used alone Or mix 2 or more types for use.

The contact angle between the fiber 11F (synthetic fiber) constituting the fiber block 11 and water is preferably greater than the contact angle between the water-absorbent fiber 12F and water. That is, the hydrophilicity of the synthetic fiber is preferably the same as the hydrophilicity of the water-absorbent fiber 12F, or lower than the hydrophilicity of the water-absorbent fiber 12F. By establishing the relationship between the hydrophilicity and the degree of hydrophilicity, body fluids can move more smoothly from the fiber block 11 to the water-absorbent fibers 12F, or in the opposite direction, and further improvements in the liquid absorbency of the absorbent core 40 can be expected. improve. In order to realize the size relationship of "constituent fiber 11F ≧ water-absorbent fiber 12F" regarding the contact angle with water, it is only necessary to appropriately adjust the degree of hydrophilization of the constituent fiber 11F by the hydrophilizing agent. The contact angle between the water-absorbent fiber 12F and water is assumed to be equal to or less than the contact angle between the constituent fiber 11F and water, and is preferably 60 degrees or less, further preferably 40 degrees or less.

In addition, the contact angle between the fiber 11F (synthetic fiber) constituting the fiber block 11 and water is preferably smaller than the contact angle between the front sheet 2 and water. That is, the hydrophilicity of the constituent fibers 11F is preferably higher than the hydrophilicity of the front sheet 2 . By establishing the relationship between the hydrophilicity and the degree of hydrophilicity, the sanitary napkin 1 exerts the effect that the liquid absorbed by the front sheet 2 is quickly taken into the absorbent core 40 , and furthermore, through the above-mentioned absorbent core The liquid diffusion effect in the plane direction inside the body 40, especially in the above-mentioned excretion part facing part located in the center of the longitudinal central area B (refer to Figure 1) of the sanitary napkin 1, reduces the front sheet 2 and the absorbent core 40 The amount of liquid retained, and furthermore, after liquid absorption, the cushioning properties of the part facing the excretion part and its vicinity are also excellent. In order to achieve this with respect to the contact angle with water, "Front sheet 2 > Constituent fiber 11F (fiber block 11) ≧ Water-absorbent fiber 12F" The size relationship may be adjusted appropriately by not only adjusting the degree of hydrophilization of the constituent fibers 11F by the hydrophilizing agent, but also subjecting the front sheet 2 to the same hydrophilization treatment as that of the constituent fibers 11F, if necessary.

In the absorbent core 40, the content mass ratio of the fiber block 11 and the water-absorbent fiber 12F is not particularly limited as long as it depends on the types of the fiber block 11's constituent fiber 11F (synthetic fiber containing a hydrophilizing agent) and the water-absorbent fiber 12F. It suffices to make appropriate adjustments. However, from the viewpoint of exerting the specific effect of the present invention more reliably, the content mass ratio of the fiber block 11 and the water-absorbent fiber 12F is calculated as the former (fiber block 11)/the latter (water-absorbent fiber 12F). Preferably, it is 20/80~80/20, and even more preferably, it is 40/60~60/40.

The content of the fiber block 11 in the absorbent core 40 is preferably 20 mass% or more, further preferably 40 mass% or more, and more preferably 80 mass% relative to the total mass of the absorbent core 40 in a dry state. or less, and more preferably 60 mass% or less.

The content of the water-absorbent fiber 12F in the absorbent core 40 is preferably 20 mass% or more, further preferably 40 mass% or more, and more preferably 80 mass% based on the total mass of the absorbent core 40 in a dry state. % or less, and 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 more preferably 640 g/m ² or less, further preferably 480 g/m 2 ² or less.

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

As described above, the excellent effects exerted by the absorbent core 40 include, specifically, cushioning properties, compression recovery properties, and liquid absorption properties in either a dry state or a wet state. The effect of excellent penetrability, liquid diffusivity, etc. largely depends on the fiber block 11 composed of the constituent fiber 11F containing the hydrophilizing agent. The distribution state of the fiber block 11 in the absorbent core 40 can be compared The expression of the effect achieved by such an absorbent core 40 has a considerable influence.

For example, if the fiber block 11 is present in a sanitary napkin that bisects the absorbent core 40 in the thickness direction (the direction orthogonal to the skin-facing surface or non-skin-facing surface of the absorbent core 40) On the side of 1 that is relatively close to the wearer's skin, that is, the skin-facing side of the absorbent core 40 (the front sheet 2 side), the fiber block 11 having lower liquid retention than the water-absorbent fiber 12F is present in the wearer. As a result, body fluids are smoothly transferred from the skin-opposing surface side to the non-skin-opposing surface side (back sheet 3 side), and the liquid introduction property of the absorbent core 40 is improved, resulting in reduced front surface area. The liquid residue in the skin-facing surface of the sheet 2 can suppress uncomfortable moisturizing or sticky feeling, thereby improving the wearing feel of the sanitary napkin 1 .

In addition, the expression of the functional effects (cushioning properties, liquid absorbency, etc.) achieved by the absorbent core 40 is not only affected by the distribution state of the fiber blocks 11 in the absorbent core 40, but also by the orientation of the fiber blocks 11 Sexuality is greatly affected. Basically, if the plurality of fiber blocks 11 included in the absorbent core 40 are aligned with the thickness direction of the absorbent core 40 (the direction orthogonal to the skin-facing surface or non-skin-facing surface of the absorbent core 40 ) are randomly oriented because they can achieve a high level of cushioning properties, especially cushioning properties and compression recovery properties of the absorbent core 40 in a wet state, which is preferable. Here, "the fiber blocks 11 are randomly oriented with respect to the thickness direction of the absorbent core 40" means focusing on the long axis direction of each of the plurality of fiber blocks 11 (main body portion 110), that is, the length of the basic surface 111 In the case of the direction (maximum diameter length direction, diameter direction), the long axis directions of each of the plurality of fiber blocks 11 included in the absorbent core 40 are inconsistent with each other. In the case where a known fiber stacking device equipped with a rotating drum is used and the absorbent core 40 is manufactured according to the usual practice. At this time, the plurality of fiber blocks 11 included in the absorbent core 40 are usually in a state of being randomly aligned with respect to the thickness direction of the absorbent core 40 .

Moreover, it is preferable that at least a part of the plurality of fiber blocks 11 included in the absorbent core 40 is aligned so that the long axis direction (the length direction of the basic surface 111 ) is along the thickness direction of the absorbent core 40 . Here, "aligned along the thickness direction" means that the angle between the long axis direction of the fiber block 11 and the thickness direction of the absorbent core 40 is 45 degrees or less. If the fiber blocks 11 are aligned in the absorbent core 40 in such a way that the long axis direction of the fiber blocks 11 is along the thickness direction of the absorbent core 40, then compared to the case where the fiber blocks 11 are not aligned in this way For example, the long axis direction of the fiber block 11 is consistent with the direction orthogonal to the thickness direction of the absorbent core 40, that is, the fiber block 11 is along the skin-facing surface or the non-skin-facing surface of the absorbent core 40. In particular, the recovery properties of the absorbent core 40 in the wet state can be further improved when the absorbent core 40 is oriented in a plane direction. It is preferable that the total fiber block 11 contained in the absorbent core 40 is 30 mass % or more, and further preferably 50 mass % or more, such that the long axis direction of the fiber block 11 is along the absorbent core 40 Orientation in the thickness direction.

As mentioned above, the excellent liquid absorbency (liquid introduction, liquid diffusion, etc.) of the absorbent core 40 largely depends on the basic surface 111 and the skeleton surface 112 existing on the surface of the main body 110 of the fiber block 11 The gaps between the fibers that constitute the fiber 11F. In this regard, the constituent fibers 11F of the fiber block 11 are preferably aligned in the plane direction of the basic plane 111 . With this structure, a plurality of interfiber voids constituting the fibers 11F are formed on the basic surface 111 of the fiber block 11 (main body portion 110), so the liquid absorbency of the absorbent core 40 can be further improved. Here, "the constituent fibers 11F are aligned in the plane direction of the basic plane 111" means a state in which the constituent fibers 11F extend along the plane direction of the basic plane 111. It is more preferable that the constituent fibers 11F extend along the length direction of the basic surface 111 . Furthermore, the total number of constituent fibers 11F present on the basic surface 111 is preferably 30% or more, and further preferably It is better if more than 50% is aligned in the plane direction (preferably the length direction) of the basic plane 111 .

The absorbent core 40 may contain other components besides the fiber block 11 and the water-absorbent fiber 12F, and a water-absorbent polymer can be exemplified as the other component. As the water-absorbing polymer, those in the form of particles are generally used, and those in the form of fibers may also be used. When a particulate super-absorbent polymer is used, its shape may be any one of spherical, block-like, bag-like or unfixed shapes. The average particle diameter of the water-absorbent polymer is preferably 10 μm or more, more preferably 100 μm or more, and further preferably 1000 μm or less, further preferably 800 μm or less. As the water-absorbing polymer, polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid may generally be 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, further preferably 10% by mass or more, and more preferably 60% by mass relative to the total mass of the absorbent core 40 in a dry state. % or less, and more preferably 40 mass% or less.

The basis weight of the water-absorbent polymer in the absorbent core 40 is preferably 10 g/m ² or more, more preferably 30 g/m ² or more, and more preferably 100 g/m ² or less, further preferably 70 g/m 2 m ² or less.

The absorbent core 40 may be manufactured in the same manner as absorbent cores containing such fibrous materials. As described above, the fiber block 11 can be made by cutting a raw fiber sheet (a sheet that has the same composition as the fiber block 11 and is larger in size than the fiber block 11 ) as a raw material as shown in FIG. 6 using a cutting device such as a cutter. The plurality of fiber blocks 11 produced by cutting in two intersecting (orthogonal) directions are "fixed-shaped fiber aggregates" with uniform shapes and sizes (for example, the main body 110 is in the shape of a rectangular parallelepiped) . The absorbent core 40 including the fiber block 11 and the water-absorbent fiber 12F can be produced according to conventional practices using, for example, a known fiber stacking device equipped with a rotating drum. Typically, this fiber stacking device is provided with a drum having a stacking recess formed on the outer peripheral surface, and an internal device for transporting the raw materials (fiber block 11, water-absorbent fiber 12F) of the absorbent core 40 to the stacking recess. The duct of the flow path causes the drum to rotate around the rotation axis along the drum circumferential direction and transports the air flow (vacuum air) generated in the flow path by suction from the inside side of the drum. The raw material fibers are accumulated in the concave portion for gathering. The fiber accumulation formed in the accumulation recessed portion by this fiber accumulation step is the absorbent core 40 . The basis weight of the absorbent core 40 is preferably 100 g/m ² or more, more preferably 200 g/m ² or more, and further preferably 800 g/m ² or less, further preferably 600 g/m ² or less.

The absorbent core 40 (absorbent body 4) having the above-mentioned structure is soft and has excellent cushioning properties and excellent compression recovery properties. It deforms well in response to external force and quickly returns to its original state when the external force is removed. The properties of such an absorbent core can be evaluated in terms of compression workload (WC) and recovery rate from compression (RC). The compression workload is a measure of the cushioning properties of the absorbent core. The larger the WC value, the higher the cushioning properties can be evaluated. The compression recovery rate is a measure of the degree of recovery when the absorbent core is compressed and then released from the compressed state. The larger the RC value, the higher the compression recovery property can be evaluated. Furthermore, considering the role of the absorbent core 40 in absorbing and retaining liquid, not only in a dry state but also in a wet state by absorbing body fluids, the absorbent core 40 preferably has a WC value of The RC value is larger. In order for the absorbent core 40 to have such characteristics in a wet state, as mentioned above, it is effective to use synthetic fibers containing a hydrophilizing agent as the constituent fibers 11F of the fiber block 11. If the synthetic fibers are non-water-absorbent and thermoplastic, Better.

<Measurement method of compression workload (WC) and compression recovery rate (RC)>

As is known to all, the compression workload (WC) and compression recovery rate (RC) of the absorbent core 40 can be expressed by measured values in KES (Kawabata evaluation system, Kawabata Evaluation System) manufactured by Kado Technology Co., Ltd. (Reference: Standardization and analysis of texture evaluation (2nd edition); Author Kawabata Nobuo; released on July 10, 1980). Specifically, the automated compression test device KES-FB3-AUTO-A manufactured by Kado Technology Co., Ltd. can be used to measure the compression workload and compression recovery rate. The measurement sequence is as follows.

Prepare a 195 mm × 68 mm quadrilateral-shaped sample (absorbent body not wrapped with a sheet material, i.e., absorbent core) when viewed from above, and install it on the test bench of the compression test device. Then, the sample was compressed between steel plates with a circular plane having an area of 2 cm ² . The compression speed was set to 0.01cm/sec, and the maximum compression load was set to 490.2mN/cm ² . The recovery process is also measured at the same speed. The compression workload (WC) is expressed by the following formula. In the formula, T _m , T _o and P respectively represent the thickness at 490.2mN/cm ² (4.9kPa) load, the thickness at 4.902mN/cm ² (49Pa) load, and the load at measurement (mN/cm ² ). .

In addition, the compression recovery rate (RC) is expressed by [WC'/WC]×100, which is the ratio of the compression workload (WC) during compression to the compression recovery workload (WC') when returning from the compression state to the original state. .

In addition, the "absorbent core in a dry state" that is the measurement object of the above measurement method is prepared by leaving the absorbent core that is the measurement object in an environment with an air temperature of 23°C and a relative humidity of 50% RH for 24 hours. Moreover, the "absorbent core in a wet state" which is the measurement object of the said measurement method was prepared as follows. Place the absorbent core in a dry state horizontally so that the side facing the skin becomes the upper side, and overlap an acrylic resin plate with a cylinder with an injection port of 1 cm in diameter at the bottom on the skin of the absorbent core. On the opposite side, 5.0 g of defibrinated horse blood was injected from the injection port and maintained in this state for 1 minute after injection to prepare. Furthermore, the defibrinated horse blood system injected into the absorbent core as the measurement object was manufactured by Japan BIO-TEST Co., Ltd. It is obtained by adjusting the viscosity of defibrinated horse blood to 8cp at a liquid temperature of 25°C. In addition, the viscosity is determined by the rotor name L/Adp (rotor code) in the TVB-10M viscometer manufactured by Toki Industrial Co., Ltd. 19) The viscosity when the rotor is measured at a rotation speed of 30 rpm. In addition, in order to prevent the measurement device from getting wet when performing the above measurement method, Saran Wrap (registered trademark) manufactured by Asahi Kasei Co., Ltd. was cut into 4 cm × 4 cm pieces and covered with a Saran Wrap (registered trademark) sheet. The portion of the measuring device corresponding to the injection point of defibrinated horse blood and its peripheral portion corresponding to the measurement target (absorbent core).

As mentioned above, the present invention has been described based on the embodiments thereof. However, the present invention is not limited to the above-described embodiments and can be appropriately modified.

For example, in the above-mentioned embodiment, the absorbent body 4 is composed of the absorbent core 40 and the covering sheet 41 covering the absorbent core 40, but the covering sheet 41 may not be included.

Furthermore, in the absorbent core of the present invention, not all the fiber blocks (synthetic fiber aggregates) contained therein may be fixed-shaped fiber aggregates such as the fiber blocks 11, as long as they do not deviate from the gist of the present invention. Then, in addition to the fixed-shaped fiber aggregate, a very small amount of non-fixed-shaped fiber aggregate may also be included.

The absorbent article of the present invention broadly includes articles for absorbing body fluids discharged from the human body (urine, loose feces, menstrual blood, sweat, etc.). In addition to the above-mentioned menstrual sanitary napkins, it also includes sanitary napkins and sanitary napkins with fixed belts. So-called expandable disposable diapers, panty-type disposable diapers, incontinence pads, etc. Regarding the embodiments of the present invention described above, the following appendix is further disclosed.

<1> An absorbent body that includes a fiber block containing synthetic fibers and water-absorbent fibers, and a plurality of the fiber blocks are intertwined with each other or the fiber block and the water-absorbent fiber are intertwined with each other, and the fiber blocks have an opposite direction. The main body is formed by dividing the two basic planes and the skeleton plane intersecting the two basic planes, and the above-mentioned synthetic fiber contains a hydrophilizing agent.

<2> The absorbent body according to the above <1>, wherein the contact angle between the synthetic fibers and water is 75 degrees or less, preferably 70 degrees or less, further preferably 60 degrees or less, more preferably 50 degrees or less.

<3> The absorbent body according to the above <1> or <2>, wherein the contact angle between the synthetic fiber and water is greater than the contact angle between the water-absorbent fiber and water.

<4> The absorbent body according to any one of <1> to <3> above, wherein the synthetic fiber is a non-water-absorbent fiber.

<5> The absorbent body according to any one of the above <1> to <4>, wherein the total area of the two basic planes is greater than the total area of the skeleton plane.

<6> The absorbent body according to any one of the above <1> to <5>, wherein the number of fiber ends per unit area present in each of the above-mentioned basic plane and the above-mentioned skeleton plane is present on the skeleton plane. The above quantity is greater than the above quantity that exists in this fundamental.

<7> The absorbent body according to the above <6>, wherein the ratio N 1 of the number N ₁ of the fiber ends per unit area of the above-mentioned basic surface and the number N ₂ of the above-mentioned fiber ends per unit area of the above-mentioned skeleton surface is N ₁ /N ₂ is 0 or more and 0.90 or less, preferably 0.05 or more and 0.60 or less.

<8> The absorbent body according to the above <6> or <7>, wherein the number of fiber ends per unit area of the basic surface is 0/mm ² or more and 8/mm ² or less, preferably 3 More than pcs/mm ² , less than 6 pcs/mm ² .

<9> The absorbent body according to any one of the above <6> to <8>, wherein the number of the fiber ends per unit area of the skeleton surface is 5/mm ² or more and 50/mm ² or less, Preferably, it is 8 pieces/ ^mm2 or more and 40 pieces/ ^mm2 or less.

<10> The absorbent body according to any one of the above <1> to <9>, wherein the fiber block is composed of fibers extending outward from the main body part and has a fiber density lower than that of the main body part. part, and at least one of the above-mentioned extended fiber parts is included from the above-mentioned body The extended fiber bundle part of the plurality of fibers extending from the part.

<11> The absorbent body according to any one of the above <1> to <10>, wherein the main body portion forms a rectangular parallelepiped shape.

<12> The absorbent body according to any one of the above <1> to <11>, wherein the plurality of fiber blocks included in the absorbent body are randomly aligned with respect to the thickness direction of the absorbent body.

<13> The absorbent body according to any one of the above <1> to <12>, wherein the above-mentioned basic surface has a shape that is long in one direction, and at least a part of the plurality of the above-mentioned fiber blocks included in the above-mentioned absorbent body is shaped like this The length direction of the base plane is aligned in such a way that it follows the thickness direction of the absorber.

<14> The absorbent body according to any one of the above <1> to <13>, wherein the content mass ratio of the fiber block and the water-absorbent fiber is 20/80 to 80/20 in terms of the former/the latter.

<15> The absorbent body according to any one of the above-mentioned <1> to <14>, wherein the constituent fibers of the fiber block are aligned in the plane direction of the basic plane.

<16> The absorbent body according to any one of the above <1> to <15>, wherein the fiber block in the absorbent body may be combined with other fiber blocks or the water-absorbent fiber by entanglement. It exists in a state of intertwining with other fiber blocks or the above-mentioned water-absorbent fibers.

<17> The absorbent body according to the above <16>, wherein the total number of the fiber blocks bonded by entanglement and the fiber blocks in an entangled state is preferably half of the total number of fiber blocks in the absorber. More preferably, it accounts for more than 70%, and more preferably, it accounts for more than 80%.

<18> The absorbent body according to any one of the above <1> to <17>, wherein the total number of the fiber blocks having joint portions with other fiber blocks or the water-absorbent fibers is preferably 70% or more, and further Preferably, at least 80% of the joints are formed by the interlacing of fibers.

<19> The absorbent body according to any one of the above <1> to <18>, wherein the fiber block is derived from a nonwoven fabric.

<20> The absorbent body according to any one of the above <1> to <19>, wherein the hydrophilizing agent includes an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. 1 or 2 or more types in a group of agents.

<21> The absorbent body according to the above <20>, wherein the hydrophilizing agent contains an anionic surfactant.

<22> The absorbent body according to the above <21>, wherein the anionic surfactant contains an alkyl sulfosuccinate.

<23> An absorbent article including the absorbent body according to any one of the above <1> to <22>.

<24> The absorbent article according to the above <23>, wherein a liquid-permeable front sheet is provided on one side of the absorbent body, and the fiber block is present when the absorbent body is bisected in the thickness direction. The side relatively close to the front sheet side.

<25> The absorbent article according to the above <23> or <24>, which is provided with the above-mentioned absorbent body and a front sheet disposed on the skin-facing side of the absorbent body, and the contact angle between the above-mentioned synthetic fiber and water is smaller than the above-mentioned The contact angle between the front sheet and water is greater than the contact angle between the above-mentioned water-absorbent fibers and water.

[Example]

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

[Examples 1~5]

An absorbent core was produced and used as a sample of the absorbent body of each example. Specifically, fiber blocks and water-absorbent fibers are used as the fiber material of the absorbent core, and are produced in accordance with common practice using a known fiber stacking device. The fiber block is produced by cutting the raw fiber sheet into Made in a small square shape.

As the raw fiber sheet of the fiber block, a non-water-absorbent thermoplastic fiber containing polyethylene resin fiber and polyethylene terephthalate resin fiber (non-water-absorbent fiber, fiber diameter 1.8 μm) is used as the base of the fiber. A hot-air nonwoven fabric (a fiber sheet that constitutes a thermally fused portion of the fibers) weighing 21g/ ^m2 and having a thickness of 0.6mm. The constituent fibers of the fiber block are in a form in which the surface hydrophilizing agent of the non-water-absorbent thermoplastic fiber as the raw material fiber is attached to the film. In Examples 1 to 4, Composition A having the following composition of 0.4% by mass relative to the mass of the constituent fibers of the fiber block was used as the hydrophilizing agent. Moreover, in Example 5, composition A and a commercially available surfactant (Pelex OT-P; manufactured by Kao Co., Ltd.) were used as the hydrophilizing agent. The usage amounts of these hydrophilizing agents were based on the amount of the fiber block. The constituent fiber mass was set to 0.4% by mass for the former and 0.2% by mass for the latter. Coniferous bleached kraft pulp (NBKP) with a fiber diameter of 2.2 μm was used as the absorbent fiber. The fiber block (fixed-shaped synthetic fiber assembly) used in the absorbent core has a rectangular parallelepiped-shaped main body as shown in Figure 5(a). The short side 111a of the basic surface 111 is 0.8 mm, and the long side 111b is 0.8 mm. 3.9mm, thickness T is 0.6mm. Furthermore, the number of fiber ends per unit area in the basic plane 111 is 3.2 pieces/mm ² , and the number of fiber ends per unit area in the skeleton plane 112 is 19.2 pieces/mm ² . In the absorbent core of each embodiment, the fiber pieces are distributed at high density and evenly.

(Composition of composition A)

‧Alkyl phosphate potassium salt (potassium hydroxide neutralized product of GRIPPER 4131 manufactured by Kao Co., Ltd.) 25% by mass

‧Dialkyl sulfosuccinate sodium salt (Pelex OT-P manufactured by Kao Co., Ltd.) 10% by mass

‧Alkyl (octadecyl) betaine (Amphitol 86B manufactured by Kao Co., Ltd.) 15 mass %

‧Polyoxyethylene (addition molar number: 2) octadecylamide (Amisol SDE manufactured by Kawaken Fine Chemicals) 30 mass%

‧Polyoxyethylene, polyoxypropylene modified silicone (X-22-4515 manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 20% by mass

[Comparative example 1]

The absorbent core of a commercially available menstrual sanitary napkin (trade name "Tanom Pew Slim 23cm" manufactured by Jiaolian Co., Ltd.) was directly used as the absorbent body of Comparative Example 1. In Comparative Example 1, the absorbent core system synthetic fibers and cellulosic fibers (hydrophilic fibers) are mixed and do not contain fiber lumps.

[Comparative example 2]

The same procedure as in Examples 1 to 5 was performed except that a non-fixed-shaped non-woven fabric piece was used as the fiber block and a hot air step was performed on the absorbent core so that the non-woven fabric pieces included in the absorbent core were thermally fused to each other. Manufacture of absorbers. In the hot air step for the above-mentioned absorbent core, a mixed assembly of non-woven fabric sheets and pulp fibers (length 210 mm × width 66 mm) is allowed to stand in an electric dryer (for example, manufactured by Isuzu Manufacturing Co., Ltd.) at a temperature of 140°C. 30 minutes to heat-fuse the nonwoven fabric pieces to each other. The non-fixed-shaped non-woven fabric sheet used is made by pulling the same hot air-through non-woven fabric used in the embodiment in any direction, and its diameter length when viewed from above is approximately 25 mm. Moreover, in Comparative Example 2, the above-mentioned composition A was used as a hydrophilizing agent applied to the constituent fibers of the nonwoven fabric sheet.

[Performance evaluation]

For the absorbent cores of each example and comparative example, the compression workload in the dry state (d-WC), the compression workload in the wet state (w-WC), and the dry state were measured by the above method. Compression recovery rate under conditions (d-RC), compression recovery rate under wet conditions (w-RC). The results are shown in Table 1 below.

As shown in Table 1, the absorbent body of each example contains a fixed-shaped fiber block that has been hydrophilized. The fiber block includes synthetic fibers containing a hydrophilizing agent and consists of two basic planes and a skeleton plane intersecting the two basic planes. Division is formed, so compared to Comparative Examples 1 and 2 that do not include such fiber blocks, the compression workload is larger in both the dry state and the wet state. In addition, the compression recovery rate is also greater in the dry state and the wet state. A higher value is displayed in any of the wet states. In particular, from the comparison between each Example and Comparative Example 2, it can be seen that in order to obtain an absorbent body that has a large compression workload even in a wet state and has excellent cushioning properties, it is effective to hydrophilize the fiber blocks in the absorbent body. In addition to chemical treatment, the fiber blocks are set into a fixed shape and the fiber blocks are bonded to each other through entanglement.

[Industrial availability]

The absorption system of the present invention has excellent cushioning and compression recovery properties and is responsive to external forces. It has good properties and can be flexibly deformed, thereby improving the wearing feel when applied to absorbent articles. Furthermore, the absorbent body of the present invention can exhibit this excellent effect not only before absorbing liquid but also in a wet state after absorbing and retaining liquid.

Furthermore, since the absorbent article of the present invention includes this high-quality absorbent body, it has excellent wearing comfort and leakage prevention properties.

1: sanitary napkin

2: Front sheet

3: Back sheet

4:Absorbent body

5:Absorbent body

6: Side sheet

11: Fiber block

12F: water-absorbent fiber

40:Absorbent core

41: chip-coated material

Y: Horizontal

Claims (24)

An absorbent body comprising fiber blocks and water-absorbent fibers containing synthetic fibers as constituent fibers, and a plurality of the fiber blocks are intertwined with each other or the fiber blocks and the water-absorbent fibers are intertwined with each other, and the fiber blocks have opposite directions. The main body portion is divided into two basic planes and a skeleton plane intersecting the two basic planes. The synthetic fiber contains a hydrophilizing agent, and the main body portion forms a rectangular parallelepiped shape. An absorbent body comprising fiber blocks and water-absorbent fibers containing synthetic fibers as constituent fibers, and a plurality of the fiber blocks are intertwined with each other or the fiber blocks and the water-absorbent fibers are intertwined with each other, and the fiber blocks have opposite directions. The main body portion is divided into two basic planes and a skeleton plane intersecting the two basic planes, the above-mentioned synthetic fiber contains a hydrophilizing agent, and the above-mentioned basic plane has a shape that is longer in one direction, and the above-mentioned absorbent body contains a plurality of At least a part of the fiber block is aligned in such a manner that the length direction of the basic surface is along the thickness direction of the absorbent body. The absorbent body according to claim 1 or 2, wherein the contact angle between the synthetic fiber and water is 75 degrees or less. The absorbent body according to claim 1 or 2, wherein the contact angle between the synthetic fibers and water is greater than the contact angle between the water-absorbent fibers and water. The absorbent body of claim 1 or 2, wherein the synthetic fibers are non-water-absorbent fibers. The absorbent body of claim 1 or 2, wherein the total area of the two basic planes is greater than the total area of the skeleton plane. The absorbent body according to claim 1 or 2, wherein the number of fiber ends per unit area present in each of the above-mentioned basic surface and the above-mentioned skeleton surface is greater on the skeleton surface than on the basic surface. The absorbent body of Claim 7, wherein the ratio N ₁ /N ₂ of the number N ₁ of the fiber ends per unit area of the above-mentioned basic surface and the number N ₂ of the fiber ends per unit area of the above-mentioned skeleton surface is Above 0 and below 0.90. The absorbent body according to claim 7, wherein the number of the fiber ends per unit area of the basic surface is 0/mm ² or more and 8/mm ² or less. The absorbent body of claim 7, wherein the number of fiber ends per unit area of the skeleton surface is 5/mm ² or more and 50/mm ² or less. The absorbent body according to claim 1 or 2, wherein the fiber block has an extended fiber portion composed of fibers extending outward from the main body portion and having a fiber density lower than that of the main body portion, and At least one of the above-mentioned extended fiber parts is an extended fiber bundle part including a plurality of fibers extended from the above-mentioned main body part. The absorbent body of claim 1 or 2, wherein the plurality of fiber blocks contained in the absorbent body are randomly aligned with respect to the thickness direction of the absorbent body. The absorbent body according to claim 1 or 2, wherein the content mass ratio of the fiber block and the water-absorbent fiber is 20/80~80/20 in terms of the former/the latter. The absorbent body according to claim 1 or 2, wherein the constituent fibers of the fiber block are aligned in the plane direction of the basic plane. The absorbent body of claim 1 or 2, wherein in the above-mentioned absorbent body, in addition to being combined with other fiber blocks or the above-mentioned water-absorbent fibers through entanglement, the above-mentioned fiber blocks can also be interlaced with other fiber blocks or the above-mentioned water-absorbent fibers. state exists. The absorbent body according to claim 15, wherein the total number of the fiber blocks bonded by entanglement and the fiber blocks in an entangled state accounts for more than half of the total number of fiber blocks in the absorber. The absorbent body according to claim 1 or 2, wherein more than 70% of the total number of the fiber blocks having joint portions with other fiber blocks or the water-absorbent fibers has the joint portions formed by entanglement of fibers. The absorbent body of claim 1 or 2, wherein the fiber blocks are from nonwoven fabrics. The absorbent body according to claim 1 or 2, wherein the hydrophilizing agent includes one selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants, or 2 or more types. The absorbent body according to claim 19, wherein the hydrophilizing agent includes an anionic surfactant. The absorbent body according to claim 20, wherein the anionic surfactant contains alkyl sulfosuccinate. An absorbent article provided with the absorbent body according to any one of claims 1 to 21. The absorbent article of claim 22, wherein a liquid-permeable front sheet is provided on one side of the absorbent body, and the fiber block is present at a distance from the front surface when the absorbent body is divided into two halves in the thickness direction. The side of the sheet that is relatively close. The absorbent article of Claim 22, which includes the absorbent body and a front sheet disposed on the skin-facing side of the absorbent body, and the contact angle between the synthetic fibers and water is smaller than the contact angle between the front sheet and water. And it is above the contact angle between the above-mentioned water-absorbent fiber and water.