TW202038879A - Absorbent article - Google Patents

Abstract

This absorbent article (1) has: an excretion part-facing region (B) which is placed to face an excretion part of a wearer during use; and a front region (A) and a rear region (C) positioned in front of and behind the region (B) in the longitudinal direction (X). The absorbent article (1) is provided with an absorbent body (4). The absorbent body (4) includes: fiber masses (11) containing synthetic fibers (11F); and water absorbent fibers (12F). In the absorbent body (4), the ratio of the content by mass of the fiber masses (11) to the total content by mass of the fiber masses (11) and the water absorbent fibers (12F) (fiber mass content) is larger in the excretion part-facing region (B) than in the front region (A) and the rear region (C), and in the excretion part-facing region (B), the ratio is smaller on the skin facing surface side (B1) of the absorbent body than on the non-skin facing surface side (B2) of the absorbent body.

Description

Absorbent articles

The present invention relates to an absorbent article.

Generally speaking, absorbent articles such as disposable diapers and menstrual napkins include a front sheet placed relatively close to the wearer’s skin, and a back face placed relatively far from the wearer’s skin. It is composed of a sheet and an absorber interposed between the two sheets. Typically, the absorbent body is composed mainly of water-absorbing fibers such as wood pulp, and further contains water-absorbing polymer particles. Regarding absorbents used in absorbent articles, a major issue lies in the improvement of various properties such as flexibility, cushioning, compression recovery, and shape retention.

As an improvement technology of an absorber, for example, Patent Document 1 describes an absorber that contains thermoplastic resin fibers and cellulose-based water-absorbing fibers, and the thermoplastic resin fibers are exposed on the surface of the absorbent body on the side of the front sheet. Both the surface of the back sheet side of the absorber. According to the absorber described in Patent Document 1, the thermoplastic resin fiber functions as a skeleton for holding other components of the absorber, such as cellulose-based water-absorbent fibers, and is therefore soft and hard to wrinkle.

Patent Document 2 describes an absorbent body that contains a nonwoven fabric sheet and water-absorbent fibers. The nonwoven fabric sheet contains thermally fusible fibers, and the fibers are bonded in advance to give a three-dimensional structure; and the nonwoven fabric sheet is uniformly distributed throughout the absorbent body. The three-dimensional structure of the non-woven fabric sheet is manufactured by crushing the non-woven fabric into fine flakes using crushing means such as shredding, and due to the manufacturing method, it is formed into an indefinite shape as described in Figures 1 and 3 of the document. There is no part that looks like a plane. In Patent Document 2, as a preferred form of the absorber described in this document, a non-woven fabric sheet formed by heat-fusing each other is described. According to the absorbent body described in Patent Document 2, the non-woven fabric sheet has a three-dimensional structure, and therefore voids are formed in the absorbent body, so that the restorability when absorbing moisture is improved, and as a result, the water absorption performance is improved.

Patent Documents 3 and 4 describe an absorbent article that includes a member that is different from an absorbent body and has excellent cushioning properties. In the absorbent article described in Patent Document 3, a cushioning material including a film having elasticity, a sheet obtained by performing uneven processing on a fiber assembly, and the like are arranged on the upper part, lower part or inside of the absorber. In the absorbent article described in Patent Document 4, a buffer layer composed of an aggregate of fine pieces of non-woven fabric is arranged between the surface sheet and the absorbent body. Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2015-16296 Patent Document 2: Japanese Patent Laid-Open No. 2002-301105 Patent Document 3: Japanese Patent Laid-Open No. 2000-316902 Patent Document 4: Japanese Patent Laid-Open No. 2003-52750

The present invention is an absorbent article, which has a longitudinal direction corresponding to the front and rear directions of the user, and a transverse direction orthogonal to the longitudinal direction, and has: an excretory portion facing area, which is arranged opposite to the user's excretory portion when in use; The front area is arranged on the longitudinal front side than the area facing the excretion portion; and the rear area is arranged on the longitudinal rear side than the area facing the excretion portion; and an absorber is provided. The above-mentioned absorbent body contains a fiber block containing synthetic fibers and water-absorbent fibers. In the absorbent body, the ratio of the content of the fiber block to the total content of the fiber block and the water-absorbent fiber is that the area facing the excretion portion is larger than the front area and the rear area, and the excretion In the facing area, the skin facing side of the absorbent body is smaller than the non-skin facing side of the absorbent body.

In order to improve the wearing feeling of absorbent articles, an effective measure is to improve the cushioning properties of the absorbent body of the absorbent article. Therefore, it constitutes an absorbent body with independent fibers as described in Patent Document 1, such as the non-woven fabric described in Patent Document 2. It is more effective to use absorbents containing fiber blocks as sheets. Moreover, as described in Patent Documents 3 and 4, the use of a member having excellent cushioning properties in addition to the absorber is also effective for improving the wearing feeling of the absorbent article. However, even if the cushioning properties of the absorbent body are improved by using these prior art techniques, if the absorbent body is prone to pleating by external forces such as body pressure applied when wearing the absorbent article, the wearing feeling of the absorbent article cannot be improved. In addition, the absorbent body is required to have liquid absorbency above a certain level. For example, if the absorbent body contains only the non-woven fabric sheet described in Patent Document 2, the liquid absorbency may decrease. Also, for example, if a member with excellent cushioning properties is arranged between the top sheet and the absorber as described in Patent Documents 3 and 4, the distance between the top sheet and the absorber becomes longer, and the liquid introduction property decreases. There is still a risk of lowering liquid absorption. Absorbers that are not easy to wrinkle when wearing absorbent articles and are excellent in cushioning and liquid introduction have not yet come out.

Therefore, the present invention relates to an absorbent article with good wearing feeling before and after excretion and excellent absorption performance.

Hereinafter, referring to the drawings, the absorbent article of the present invention will be described based on its preferred embodiment. Fig. 1 and Fig. 2 show a menstrual sanitary napkin 1 as an embodiment of the absorbent article of the present invention. The sanitary napkin 1 is equipped with: an absorbent body 4 which absorbs and retains body fluids; a front sheet 2 which is arranged on the skin-facing side of the absorbent body 4, which is in contact with the wearer's skin and has liquid permeability; and the back The sheet 3 is arranged on the non-skin facing surface side of the absorbent body 4 and has liquid impermeability. As shown in Figure 1, the sanitary napkin 1 corresponds to the front and back directions of the wearer, and has a longitudinal direction X extending from the wearer’s ventral side to the back side through the crotch and a transverse direction Y orthogonal to the longitudinal direction X. X has: the excretion facing area B, which includes the excretion facing part (excretion point) that is arranged opposite to the excretion part such as the wearer's vulva during wearing; the front area A, which is arranged in front of the excretion part The facing area B is closer to the longitudinal front side (the wearer's ventral side); and the rear area C, which is arranged on the longitudinal rear side (the wearer's back side) than the excretion portion opposed area B; thus is divided into the Three regions.

In this specification, "skin facing surface" refers to the side of the absorbent article or its constituent members (such as absorber 4) that faces the wearer's skin when wearing the absorbent article, that is, the side relatively close to the wearer's skin The "non-skin facing surface" refers to the surface of the absorbent article or its constituent members that faces the side opposite to the skin side when the absorbent article is worn, that is, the side relatively far from the wearer's skin. Furthermore, the "while wearing" here means the state of maintaining the usual proper wearing position, that is, the correct wearing position of the absorbent article.

As shown in Fig. 1, the sanitary napkin 1 has: an absorbent body 5, which has a long shape in the longitudinal direction X; and a pair of wings 5W, 5W, which are opposite from the excretory portion B of the absorbent body 5 The two sides along the longitudinal direction X respectively extend to the outer side of the transverse direction Y. The absorbent body 5 is a part of the main body of the sanitary napkin 1. It includes the front sheet 2, the back sheet 3, and the absorbent body 4, and is divided in the longitudinal direction X into a front area A, an excretion facing area B, and a rear area C. Regions.

Regarding the area facing the excretion part of the absorbent article of the present invention, when the absorbent article has wings like sanitary napkin 1, the absorbent article has wings in the longitudinal direction (length direction, X direction in the figure) Department of the area. If the sanitary napkin 1 is taken as an example, it is sandwiched between an imaginary straight line passing through the roots of the pair of wings 5W, 5W on the front side of the longitudinal direction X and extending along the transverse direction Y, and passing through the pair of wings 5W, 5W on the rear side of each The area between the roots and the imaginary straight lines extending along the transverse direction Y is the area B facing the excretion. Furthermore, in the sanitary napkin 1, a pair of wings 5W and 5W are symmetrically formed on the basis of a longitudinal center line that bisects the sanitary napkin 1 along the transverse direction Y and extends along the longitudinal direction X. The root portion on the front side and the root portion on the front side of the other wing portion 5W exist at the same position in the longitudinal direction X.

In addition, the area facing the excretion part of an absorbent article without wings (for example, disposable diapers) corresponds to a region in the middle when the absorbent article is divided into three equal parts in the longitudinal direction X.

As shown in FIG. 2, the surface sheet 2 covers the entire area of the skin facing surface of the absorber 4. On the other hand, the back sheet 3 covers the entire area of the non-skin facing surface of the absorber 4, and then extends from the edges of both sides of the absorber 4 along the longitudinal direction X to the outer side of the transverse direction Y, and the following side sheet 6 together form the side wings. The said side flap part is the part of the sanitary napkin 1 which contains the member extended from the absorber 4 to the lateral direction Y outer side. The back sheet 3 and the side sheet 6 are joined to each other by known joining means such as adhesives, heat sealing, and ultrasonic sealing at the extended portions extending from the both sides of the absorbent body 4 along the longitudinal direction X. The front sheet 2 and the back sheet 3 may be joined to the absorber 4 by an adhesive, respectively. The front sheet 2 and the back sheet 3 are not particularly limited, and various sheets previously used in absorbent articles such as menstrual sanitary napkins can be used. For example, as the top sheet 2, a single-layer or multilayer structure of non-woven fabric, or an apertured film, etc. 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 above-mentioned side flaps largely protrude toward the outside of the transverse direction Y in the excretion facing region B, whereby a pair of flaps 5W and 5W are extended on the left and right sides of the absorbent body 5 along the longitudinal direction X. 5W. As shown in FIG. 1, the wing portion 5W has a substantially trapezoidal shape with a lower bottom (longer side than the upper bottom) on the side of the absorbent body 5 in a plan view, and the wing portion 5W is formed on the non-skin facing surface. It is fixed to the adhesive part of the wing part of clothing such as shorts (not shown). The wings 5W are used by folding back to the non-skin facing surface (outer surface) side of the crotch of clothing such as shorts. Furthermore, since the wings 5W are used by folding back toward the non-skin facing surface (outer surface) of the crotch of clothing such as shorts, the non-skin facing surface of the wing 5W, which forms the wing adhesive part, is When used, it faces the wearer's skin side and becomes the skin facing surface. The wing part adhesive part is covered with a release sheet (not shown) made of film, non-woven fabric, paper, etc. before use. In addition, the skin-facing surface of the absorbent body 5, that is, the both sides of the skin-facing surface of the front sheet 2 along the longitudinal direction X, overlap with the left and right sides of the absorbent body 4 along the longitudinal direction X in a plan view In this way, a pair of side sheets 6 and 6 are arranged over substantially the entire length of the longitudinal direction X of the absorbent body 5. The pair of side sheets 6 and 6 are respectively joined to the front sheet 2 or other members by a known joining means such as an adhesive or heat embossing on a joining line (not shown) extending along the longitudinal direction X.

As shown in Fig. 1, the absorbent body 4 extends over substantially the entire length of the longitudinal direction X of the sanitary napkin 1 (absorbent main body 5), and extends from the front area A to the rear area C through the excretion facing area B. The absorber 4 is indirectly attached to human skin by being incorporated into an absorbent article like sanitary napkin 1, that is, it is indirectly attached to the skin via the back sheet 3 and other members, and the user has: skin facing The surface (the opposite surface opposite to the front sheet 2), which is arranged at a position relatively close to the user's skin of the wearer of the sanitary napkin 1 during use; and the non-skin opposite surface (with the back sheet 3) The opposite facing surface), which is arranged at a position relatively far away from the user's skin; and further has a longitudinal X corresponding to the front and back directions of the user, and a transverse Y orthogonal to the longitudinal X, and in the longitudinal X The upper has a front area A, an excretion part facing area B, and a rear area C. The front area A of the absorbent body 4 is the part of the absorbent body 4 located in the front area A of the sanitary napkin 1, and the excretion part facing area B of the absorbent body 4 is located in the excretion part facing area B of the sanitary napkin 1. The area C behind the absorber 4 is the area C behind the sanitary napkin 1 of the absorber 4. In addition, the absorber 4 may adopt a form in which it is used in direct contact with the skin without interposing a member such as a sheet, in addition to the form in which it is used indirectly against the skin.

In FIGS. 3 to 5, the absorber 4 is shown. The absorbent body 4 in this embodiment includes a liquid-absorbent absorbent core 40 and a liquid-permeable core-coating material 41 covering the outer surface of the absorbent core 40. In this way, in the present embodiment, the absorbent core 40 is wrapped by the core covering material 41 to be integrated. The absorbent core 40 constitutes the main body of the absorbent body 4, and has a shape that is long in the longitudinal direction X in a plan view as shown in FIG. 3. The absorbent core 40 is arranged on the sanitary napkin 1 so that the longitudinal direction thereof is aligned with the longitudinal direction X of the sanitary napkin 1. The absorptive core 40 and the core covering material 41 may be joined by an adhesive such as a hot-melt adhesive.

In the present embodiment, the core covering material 41 is a continuous sheet having a width that is two to three times the length of the lateral Y of the absorptive core 40, as shown in FIG. 4, covering the absorptive core 40 The entire area of the skin facing surface of the absorbent core 40 extends from the both sides of the absorbent core 40 along the longitudinal direction X to the outer side of the transverse direction Y, and the extension part is rolled under the absorbent core 40 to cover the absorbent core The whole area of the body 40 is not the opposite side of the skin. Furthermore, in the present invention, the core covering material may also cover the entire area of the non-skin facing surface of the absorbent core 40, and extend from the edges of both sides of the absorbent core 40 along the longitudinal direction X to the outer side of the transverse direction Y The extension part is rolled upwards of the absorbent core 40 to cover the entire skin-facing surface of the absorbent core 40. In addition, the core covering material may not be such a single sheet. For example, it may be composed of two sheets: one skin-side core covering material covering the skin facing surface of the absorbent core 40 ; And a sheet of non-skin-side core-coating material, which is different from the skin-side core-coating material, and covers the non-skin-facing surface of the absorbent core 40. In addition, the absorber 4 may not include the core covering material, and the absorber of the present invention includes an absorber composed only of an absorbent core.

The absorbent core 40 also refers substantially to the absorbent body 4 itself. The following description of the absorbent core 40 is also applicable to the description of the absorbent body 4 as long as it is not specifically denied. The absorbent body 4 includes a form that does not contain the core-cladding material and is composed of only an absorbent core. In the absorbent body of this form, the absorbent body and the absorbent core have the same meaning.

The absorbent core 40 is mainly composed of a core-forming material, and is typically composed only of the core-forming material. The core-forming material includes at least water-absorbent fibers 12F and fiber blocks 11 including fibers 11F. In the absorbent core 40 of this embodiment, the water-absorbent polymer 13 is further contained as a core-forming material. The constituent fibers 11F of the fiber block 11 are synthetic fibers.

In this specification, the so-called "fiber block" refers to a fiber assembly in which a plurality of fibers are integrated. Regardless of the manufacturing method of the fiber block used in the present invention, for example, it may be a fixed-shaped fiber assembly such as a sheet obtained by cutting a synthetic fiber sheet of a certain size by a cutting machine, or it may be Like the non-woven fabric sheet described in Patent Document 2, the non-woven fabric mainly composed of synthetic fibers is crushed into fine flakes, or is smashed or torn off to produce an indefinite fiber assembly. In the present invention, the absorbent body (absorbent core) may be i) only include a fixed-shaped fiber assembly as a fiber block, may be ii) only an indefinite fiber assembly as a fiber block, or also It can be iii) the shape of a fiber assembly of fixed shape and an indefinite shape of fiber assembly being mixed to form a fiber block, but it is preferable to use the shape of the above i). Regarding the indefinite fiber assembly, the fibers are randomly aligned. Therefore, the fibers protrude from various places on the surface, and the surface is rough. Therefore, the fiber assemblies are entangled with each other over the entire surface. As a result, there are various fiber assemblies. The freedom of movement is restricted and the flexibility may decrease. The fiber block 11 of this embodiment is a fixed-shaped fiber assembly as described below.

As described above, the fiber block 11 is a fiber assembly obtained by integrating a plurality of fibers 11F into a block, and there are a plurality of fibers in the absorbent core 40 while maintaining the state. Moreover, the fiber block 11 mainly contributes to the improvement of the flexibility, cushioning, compression recovery, and shape retention of the absorbent core 40 due to the shape of the fiber assembly.

There are a plurality of water-absorbent fibers 12F in the absorbent core 40, and the plurality of water-absorbent fibers 12F may be intertwined with each other, but it is preferable that they are not integrated like the constituent fibers 11F of the fiber block 11, but each exist independently. The water-absorbent fiber 12F mainly helps to improve the liquid absorption of the absorbent core 40, and also helps to improve the shape retention of the absorbent core 40.

As the water-absorbent fiber 12F, the water-absorbent fiber previously used as a material for forming the absorbent body of this absorbent article can be used. Examples of water-absorbent fibers include natural fibers such as wood pulp such as softwood pulp and hardwood pulp, non-wood pulp such as cotton pulp or hemp pulp; denatured pulp such as cationized pulp and mercerized pulp; cupra, rayon Regenerated fibers such as fibers, etc.; one of them can be used alone or two or more of them can be used in combination. The main function of the water-absorbent fiber 12F is to improve the liquid absorbency of the absorbent body 4. In view of this, the water-absorbent fiber 12F is preferably natural fiber or regenerated fiber (cellulose fiber).

The water-absorbent polymer 13 is in the form of small pieces of water-absorbent polymer in the absorbent core 40, and it mainly helps to improve the liquid absorption in the absorbent core 40. The shape of the small pieces of the water-absorbent polymer 13 is not particularly limited, and may be, for example, a spherical shape, a block shape, a bag shape, a fiber shape, or an indefinite shape. The average particle size of the water-absorbing polymer 13 is preferably 10 μm or more, more preferably 100 μm or more, and more preferably 1000 μm or less, more preferably 800 μm or less. Generally speaking, as the water-absorbing polymer 13, a polymer or copolymer of acrylic acid or an alkali metal salt of acrylic acid can be used. As examples, polyacrylic acid and polyacrylate, and polymethacrylic acid and polymethacrylate can be cited. Specifically, Aqualic CA, Aqualic CAW (all manufactured by Nippon Shokubai Co., Ltd.) and the like can be cited. (Acrylic acid) part of the sodium salt.

In the absorbent core 40, a plurality of fiber blocks 11 and water-absorbent fibers 12F are mixed. In this embodiment, the two are not simply mixed, but fiber blocks 11 or fiber blocks 11 and water-absorbent fibers 12F are mixed together. Contact. In the absorbent core 40 of the present embodiment, a plurality of fiber blocks 11 are entangled with constituent fibers (fibers 11F, 12F) in the absorbent core 40 to form a continuous fiber block. In addition, a plurality of fiber blocks 11 may be entangled with each other, and the fiber blocks 11 and the water-absorbing fibers 12F may be entangled and bonded. Furthermore, usually, a plurality of water-absorbing fibers 12F are also entangled with each other. At least a part of the plurality of fiber blocks 11 contained in the absorbent core 40 is entangled with other fiber blocks 11 or water-absorbent fibers 12F. In the absorbent core 40, there may be cases where a plurality of fiber blocks 11 contained therein are all intertwined to form a fiber block continuum, or there may be a plurality of fiber block continuums mixed in a non-combined state. Existing circumstances.

In the absorbent core 40, in addition to containing fiber blocks 11 excellent in flexibility, etc., the fiber blocks 11 or the fiber blocks 11 and the water-absorbent fibers 12F are also bonded by mutual entanglement, so the absorbent core 40 is externally bonded. The responsiveness of force is more excellent, and its flexibility, cushioning, and compression recovery are excellent. When wearing the sanitary napkin 1, the absorbent core 40 is flexibly deformed when facing external forces (for example, the wearer's body pressure of the wearer of the sanitary napkin 1) from various directions, so that the sanitary napkin 1 can be adhered to the wearer with good conformability The body. Such excellent deformation-recovery characteristics of the absorbent core 40 not only appear when the absorbent core 40 is compressed, but also when the absorbent core 40 is twisted. That is, the absorbent core 40 incorporated into the sanitary napkin 1 is arranged in a state of being sandwiched between the two thighs of the wearer when the sanitary napkin 1 is worn. Therefore, there are two thighs as the wearer performs walking movements. The movement of the part while twisting around the imaginary axis of rotation extending along the longitudinal direction X. However, even in this case, the absorbent core 40 has high deformation-recovery characteristics, so it is prompted to follow The two thighs are also easily deformed and restored by twisting external forces, so they are not easy to fold, so that the sanitary napkin 1 can be given a higher conformability to the wearer's body.

In the absorbent core 40, the fiber blocks 11 are entangled with each other or the fiber blocks 11 and the water-absorbent fibers 12F. Here, the "entanglement" of the fiber blocks 11 with each other includes the following forms A and B. Form A: The fiber block 11 is not fused with each other, but is a form in which the fibers 11F constituting the fiber block 11 are entangled with each other and joined. Form B: In the natural state of the absorbent core 40 (the state without external force), the fiber blocks 11 are not connected to each other, but in the state where an external force is applied to the absorbent core 40, the fiber blocks 11 can be equal to each other It is a form in which the fibers 11F are entangled with each other and joined together. The "state where an external force is applied to the absorbent core 40" herein refers to, for example, the state of applying the absorbent core 40 to the absorbent core (in this embodiment, the sanitary napkin 1). 40 State of applying deformation force.

In this way, in the absorbent core 40, except that the fiber block 11 and the other fiber blocks 11 or the water-absorbent fibers 12F are joined by the fibers being entangled with each other, that is, "entangled", as in the form A, it is also in the form B. It can exist in a state of being entangled with other fiber blocks 11 or water-absorbent fibers 12F. The combination achieved by the intertwining of fibers is one of the important points for more effectively presenting the functions and effects of the absorbent core 40. Among them, from the viewpoint of shape retention, it is preferable that the absorbent core 40 has a "interlace" of form A. The combination achieved by fiber entanglement does not require components and fusion, and is achieved only by fibers entangled with each other. Therefore, compared with the combination achieved by fiber fusion, the interlaced elements (fiber block 11, water absorption The fiber 12F) has a high degree of freedom of movement, so the individual elements can move within a range that can maintain their integrity as an aggregate composed of them. In this way, the absorbent core 40 has a relatively loose combination of the plurality of fiber blocks 11 or the fiber block 11 and the water-absorbent fibers 12F contained therein, and has a gentle shape retention property that can be deformed when subjected to an external force, thereby being more The high level combines shape retention, cushioning and compression recovery. Moreover, the sanitary napkin 1 provided with the high-quality absorbent core 40 can adhere to the wearer's body with good conformability, and thus has an excellent wearing feeling.

The bonding state of the absorbent core 40 achieved through the fiber block 11 does not necessarily need to be "interlaced", and a part of the absorbent core 40 may include a bonding state other than interlacing, for example, achieved by an adhesive The joining and so on.

However, for example, a known leak-proof groove is formed in the absorbent core 40 as a result of being integrated with other members of the absorbent article, and "fusion achieved through the fiber block 11" is removed from the absorbent core 40. The remaining part is the unprocessed absorbent core 40 itself, which is preferably the combination of the fiber blocks 11 with each other, or the combination of the fiber blocks 11 and the water-absorbent fibers 12F only by "fiber entanglement".

From the viewpoint of more surely presenting the effect of the absorbent core 40, the form A is the total of the "fibrous block 11 combined by entanglement" and the form B is the "fibrous block 11 in a state that can be entangled" The total number of fiber blocks 11 in the absorbent core 40 is preferably half or more, more preferably 70% or more, and still more preferably 80% or more. From the same point of view, the number of fiber blocks 11 having "intersection" of form A is preferably more than 70% of the total number of fiber blocks 11 having joints with other fiber blocks 11 or water-absorbing fibers 12F. It is more than 80%.

One of the characteristics of the absorbent core 40 is the configuration of the core forming material headed by the fiber block 11. In the absorbent core 40, as shown in FIGS. 3 to 5, the fiber blocks 11 are not uniformly distributed over the entire absorbent core 40, but are opposed to the excretion part compared to the front area A and the rear area C There are relatively many areas B, and the excretion-facing area B is relatively more present on the non-skin-facing surface side B2 than on the skin-facing surface side B1.

Furthermore, the skin-facing surface side B1 of the excretion portion facing area B of the absorbent core 40 is the skin facing side when the excretion portion facing area B of the absorbent core 40 is halved along the thickness direction. The non-skin facing side B2 refers to the non-skin facing surface in this case. The same applies to the skin-facing surface side and the non-skin-facing surface side of the front area A and the back area C of the absorbent core 40.

If the concentration of the fiber block 11 in the absorbent core 40 is compared with the total content of the fiber block 11 and the absorbent fiber 12F used in combination as the core-forming material of the absorbent core 40, it is specified "The ratio of the content of the fiber block 11 to the total content of the fiber block 11 and the absorbent fiber 12F" (hereinafter, also referred to as "fiber block occupancy rate"), the fiber block of each part of the absorbent core 40 occupies The rate is that the area B facing the excretion part is larger than the front area A and the rear area C, and in the area B facing the excretion part, the skin facing side B1 is smaller than the non-skin facing side B2.

The fiber block occupancy rate is based on the specific measurement target part of the absorbent core 40 (absorbent body 4), and the content of each of the fiber block 11 and the water-absorbent fiber 12F existing in the measurement target part is measured by mass, and then the result is measured The content of the fiber block 11 is divided by the total value of the respective content of the water-absorbent fibers 12F and the fiber block 11, and the final result is expressed as 100 points. That is, the fiber block occupancy rate (mass %)={content of fiber block 11/(content of water-absorbent fiber 12F + content of fiber block 11)}×100.

Generally, the area B facing the excretion part of the absorbent core 40 is sandwiched between the wearer's two thighs when the sanitary napkin 1 is worn, so it is easy to move around the wearer's thighs when the wearer performs a walking motion. Compared with the front area A and the rear area C, the imaginary rotation axis twisting extending along the longitudinal direction X is more susceptible to the strong action of the external force, and the wrinkles are more likely to occur. Compared with the front area A and the rear area C, the arrangement of the excretion portion facing area B of the absorbent core 40, which is relatively prone to wrinkles, is more helpful to improve cushioning, compression recovery, and shape retention. The fiber block 11 of high performance, that is, the fiber block occupancy rate of the area B facing the excretion part is higher than the fiber block occupancy rate of the front area A and the back area C, which can effectively prevent the absorbent body 4 from wrinkling when the sanitary napkin 1 is worn The bad situation.

Particularly in this embodiment, as described above, the absorbent body 4 includes an absorbent core 40 containing a core-forming material including fiber blocks 11 and water-absorbent fibers 12F, and an absorbent core 40 covering the outer surface of the absorbent core 40 The core covering material 41 is integrated with the core forming material, so it is complementary to the effect caused by the segregation of the fiber block 11 and can more reliably prevent the absorbent body 4 from wrinkling when the sanitary napkin 1 is worn.

In addition, typically, on the skin-facing surface side B1 of the excretion-facing area B of the absorbent core 40, the water-absorbent fibers 12F constitute the main body, and there is almost no fiber block 11. The skin-facing surface of this structure When the side B1 absorbs body fluids and becomes a wet state, the shape retention property tends to be significantly reduced, and there is a problem that the side B1 is easily deformed by external pressure in the wet state and is easy to wrinkle. However, the non-skin-facing surface side B2 of the absorbent core 40 adjacent to the skin-facing surface side B1 in the thickness direction is composed of synthetic fiber-containing fiber blocks 11 that are segregated and present, and the shape retention is excellent even in a wet state Therefore, even when the area B facing the excretion part of the absorbent core 40 absorbs body fluids and becomes a wet state, it can be prevented from wrinkling. If the fiber block 11 and the water-absorbent fiber 12F are intertwined at the interface between the skin-facing surface side B1 and the non-skin-facing surface side B2 and the vicinity thereof, the anti-wrinkle effect is more effective.

In addition, the excretion part of the absorbent core 40 is the part of the absorbent core 40 that first receives the body fluid excreted from the excretion part of the wearer of the sanitary napkin 1, and therefore the liquid is introduced It has excellent properties and is expected to quickly absorb body fluids into the absorbent core 40. In addition, among the core-forming materials contained in the absorbent core 40, the absorbent fiber 12F is the most contributory to the improvement of the liquid introduction, and the fiber block 11 does not contribute much to the improvement of the liquid introduction. Therefore, in the area B facing the excretion part of the absorbent core 40, with respect to the fiber block occupancy rate, there are relatively more water-absorbent fibers 12F on the skin facing side B1, instead of making "skin facing The size relationship of the face side B1<the non-skin facing surface side B2" is established so that the fiber block occupancy rate of the skin facing side B1 is smaller than the fiber block occupancy rate of the non-skin facing surface side B2. Therefore, the absorbent core 40 has excellent liquid introduction properties, and the excreted body fluid can be quickly introduced into the interior for absorption and retention. In addition, since the fiber block occupancy rate has the relationship of "excrement area B>front and rear areas A, C", in the absorbent core 40, the body fluid received by the excretion area B tends to follow the longitudinal direction X Diffuse and be absorbed. Therefore, the absorptive core 40 is also excellent in suppressing the lateral leakage of body fluids.

From the viewpoint of achieving the effect of the above-mentioned segregation of the fiber block 11 more reliably, the fiber block occupancy rate of each part of the absorbent core 40 is preferably set as follows. The fiber block occupancy rate of the non-skin facing surface side B2 of the excretion portion facing area B of the absorbent core 40 is higher than that of other parts of the absorbent core 40 (front area A, back area C, and excretion facing area The premise that the fiber block occupancy rate of the skin facing side B1) of B is preferably 50% by mass or more, more preferably 90% by mass or more, or 100% by mass, that is, it contains fiber block 11 but no water absorption at all Sex fiber 12F. The fiber block occupancy rate of the skin-facing surface side B1 of the excretion portion facing area B of the absorbent core 40 is assumed to be lower than the fiber block occupancy rate of the non-skin facing surface side B2, and is preferably 50% by mass or less, It is more preferably 10% by mass or less, and may also be 0% by mass, that is, the water-absorbing fiber 12F is contained but the fiber block 11 is not contained at all. The difference between the fiber block occupancy rate of the non-skin facing surface side B2 of the excretion portion facing area B of the absorbent core 40 and the fiber block occupancy rate of the skin facing surface side B1 is better than the former minus the latter. It is 50% by mass or more, more preferably 90% by mass or more, or 100% by mass. That is, the fiber block 11 is contained only on the non-skin facing side B2, and the fiber block 11 is not contained at all on the skin facing side B1. Typically, the fiber block occupancy rate of the front area A and the back area C of the absorbent core 40 is the same as the fiber block occupancy rate of the skin facing side B1 in the excretion portion facing area B of the absorbent core 40. set up.

From the viewpoint of more surely achieving the effect of the above-mentioned concentration of the fiber mass 11 in the excretion facing area B, it is preferable that all the fibers contained in the absorbent core 40 are present in the excretion facing area B The block 11 is 90% by mass or more, more preferably 95% by mass or more.

Regarding the excretion-facing area B of the absorbent core 40, respectively on the skin-facing surface side B1 and the non-skin-facing surface side B2, it may be 1) The fiber block occupancy rate does not change in the thickness direction but is in a fixed state, Or it may be 2) The fiber block occupancy rate gradually increases from the skin-facing surface side B1 toward the non-skin-facing surface side B2. In the form of 2) above, along the thickness direction of the absorbent core 40, the fiber block 11 does not exist or the fiber block occupancy rate is the lowest in the absorbent core 40 on the skin-facing surface and its vicinity. The excretory part facing area B of the absorbent core 40 is on the non-skin facing surface of the absorbent core 40 and its vicinity, and the fiber block 11 is present in the absorbent core 40 facing the excretory part with the highest fiber block occupancy rate Area B. About the front area A and the back area C of the absorptive core 40, you may have the form of said 1) or 2).

As a unique advantage of the form of 1) above, the following can be cited: it is easy to design independent functions on the skin-facing surface side and the non-skin-facing surface side of the absorber (absorbent core). In addition, as a unique advantage of the form of the above 2), the following points can be cited: the mixing ratio of the water-absorbent fiber and the fiber block changes gently in the thickness direction of the absorber, so even when an external force is applied to the absorber, The entangled state with the fiber block as the medium is also easy to maintain throughout the thickness direction, and the cushioning property of the absorber is easy to maintain good during use.

In addition, the fiber block occupancy rate may gradually increase as the front area A and the rear area C of the absorbent core 40 respectively go toward the excretion portion facing area B. For example, in the front area A and the rear area C, the fiber block occupancy rate gradually increases from the outer side of the longitudinal direction X toward the inner side, and the excretion facing area B may also be in the form of 1) or 2).

In this embodiment, as shown in FIG. 4(a), the excretion portion facing region B of the absorbent core 40 has in the thickness direction: the fiber block occupancy rate is preferably 50% by mass or more, more preferably 90% by mass % Or more (hereinafter, also referred to as "fiber mass enrichment site") 11P; and the fiber mass occupancy rate is preferably less than 50% by mass, more preferably less than 10 mass% (hereinafter, also referred to as " Water-absorbent fiber-enriched part") 12P; more specifically, the entire non-skin-facing surface side B2 becomes the fiber mass-enriched part 11P, and the skin-facing face B1 as a whole becomes the water-absorbent fiber-enriched part 12P. Therefore, in the area B facing the excretion portion of the absorbent core 40 shown in FIG. 4(a), the fiber block occupancy rate is on the skin facing side B1 (absorbent fiber enriched part 12P) and the non-skin facing surface The junction of side B2 (fibrous mass enrichment site 11P) greatly changes.

The 12P-based water-absorbent fiber occupancy rate of the water-absorbent fiber-enriched portion is preferably 50% by mass or more, more preferably 90% by mass or more. The "absorbent fiber occupancy rate" here refers to the ratio of the content of the absorbent fiber 12F to the total content of the fiber block 11 and the water-absorbent fiber 12F, by calculating the numerator of the above-mentioned fiber block occupancy rate "The content of the fiber block 11" is replaced by the "the content of the absorbent fiber" and it is calculated.

As shown in FIGS. 4(b) and 5, the front region A and the rear region C of the absorbent core 40 hardly contain the fiber mass 11, and the fiber mass occupancy rate of the two regions A and C is 0% by mass or close to 0% by mass, the whole becomes the water-absorbent fiber-rich site 12P.

The fiber block enrichment part 11P is mainly composed of the fiber block 11, which is typically substantially free of water-absorbent fibers 12F. Therefore, it strongly reflects the characteristics of the fiber block 11 and mainly contributes to improving the absorbent core 40 softness, cushioning, compression recovery, shape retention, etc. In the fiber mass enrichment part 11P, it is preferable that the fiber mass 11 is high-density and uniformly distributed throughout the whole. On the other hand, the water-absorbent fiber-enriched part 12P is mainly composed of water-absorbent fiber 12F. Typically, it does not substantially contain the fiber mass 11, so it strongly reflects the characteristics of the water-absorbent fiber 12F and is mainly helpful To improve the liquid introduction of the absorbent core 40. In the water-absorbent fiber-enriched part 12P, it is preferable that the water-absorbent fiber 12F is high-density and uniformly distributed throughout the whole.

Regarding the fiber block occupancy rate of each part of the absorbent core 40, as described above, the size relationship of "front area A, back area C<excrement area B" and "excretion area opposite area B" Before the establishment of the size relationship of B1 &lt; non-skin facing side B2, the position of the fiber mass-enriched part 11P and the water-absorbent fiber-enriched part 12P is not particularly limited, and the fiber mass-enriched part 11P is also acceptable. The skin-facing surface side B1 existing in the excretion-facing area B of the absorbent core 40, and the water-absorbent fiber-rich site 12P may also be present on the non-skin-facing surface side B2.

The water-absorbent fiber-enriched part 12P is preferably present from the inner side of the absorbent core 40 in the thickness direction facing the absorbent core 40 toward the inner side of the absorbent core 40, and is more preferably present throughout the thickness of the absorbent core 40. It exists to cover 30-70% of the thickness. The fiber block enrichment part 11P is preferably present from the non-skin facing side of the absorbent core 40 to the inner side of the absorbent core 40 in the thickness direction of the absorbent core 40 and exists throughout 20-80% of the thickness of the absorbent core 40, more preferably It exists to cover 30-70% of the thickness. The thickness of each of the water-absorbent fiber-enriched part 12P and the fiber mass-enriched part 11P is preferably 0.5 mm or more, more preferably 1 mm or more, and more preferably 5 mm or less, more preferably 4 mm or less. The thickness of each part of the absorbent core 40 is measured by the following method. Furthermore, the thickness of the entire absorbent core 40 (absorbent body 4), the thickness of the sanitary napkin 1, etc. can also be measured by the following method.

<Method for measuring thickness> Place the absorbent core (absorbent) in a horizontal place without wrinkles or bends, and cut out the measurement target part (for example, the skin of the absorbent core) from the absorbent core The opposite surface side or the non-skin opposite surface side) to prepare a measurement sample. Then, measure the thickness of the sample under a load of 5 cN/cm ² . Specifically, when measuring the thickness, for example, a thickness meter PEACOCK DIAL UPRIGHT GAUGES R5-C (manufactured by OZAKI MFG. CO. LTD.) is used. At this time, a circular or square flat plate (acrylic plate with a thickness of about 5 mm) whose size has been adjusted so that the load reaches 5 cN/cm ² is placed between the front end of the thickness gauge and the measurement sample to measure thickness. In thickness measurement, any 10 locations in the measurement sample are measured, and the average value of the thickness of these 10 locations is calculated, and this is used as the thickness of the measurement sample.

The thickness of the absorbent core 40 is preferably the center of the transverse Y of the front area A and the rear area C relative to the excretion-facing area B (and the absorbent core 40 halves along the transverse Y and extends along the longitudinal X The position where the imaginary straight lines overlap) is thin. Thereby, when the sanitary napkin 1 is worn, the front and back regions A and C of the absorbent core 40 easily follow clothing such as shorts, and the wearer's front body or buttocks side can be further improved. In addition, the absorbent core 40 has a structure in which at least the center in the lateral direction Y of the region B facing the excretion portion and its vicinity, that is, the center portion (the formation position of the raised portion 15 described below) is thicker than the front and rear regions A and C. Therefore, the fiber block occupancy rate of the area B facing the excretion part is more complementary than that of the front and rear areas A and C. When the sanitary napkin 1 is worn, the center part of the horizontal Y of the area B facing the excretion part of the absorbent core 40 is viewed from above. The lower overlapping part can be more closely adhered to the excretory part of the wearer. As described above, the thickness difference in the longitudinal direction X of the absorbent core 40 can be achieved by making the fiber block occupancy rate of the excretion portion facing area B of the absorbent core 40 higher than that of the front area A and the back area C. Occupancy rate.

Furthermore, typically, the absorptive core 40 has a uniform thickness in the region B facing the excretion portion over the entire length (total width) of the lateral direction Y, or as shown in FIG. 2, the thickness of the central portion of the lateral direction Y Regardless of the form of the thick-walled structure larger than the two sides, the above-mentioned size relationship is "thickness of the center (central part) in the transverse direction Y of the absorptive core 40 in the region B facing the excretion part> front When the relationship between the thickness of the absorbent core 40 in the area A and the thickness of the absorbent core 40 in the rear area C is established, "the excretory part opposes the lateral Y sides of the absorbent core 40 in the area B The relationship of the thickness>the thickness of the absorbent core 40 in the front area A and the thickness of the absorbent core 40 in the rear area C" is also established.

In the absorbent core 40, the ratio of the thickness of the front area A to the thickness of the center of the transverse direction Y of the area B facing the excretion part (or the part with the largest thickness in the area B) is lowered before the former<the latter, and the former/ The latter is preferably 0.1 or more, more preferably 0.3 or more, and more preferably 0.9 or less, more preferably 0.8 or less. The ratio of the thickness of the rear region C to the thickness of the center of the lateral direction Y of the region B facing the excretion portion (or the part with the largest thickness in the region B) is also preferably set in the same manner as described above. The thickness (the maximum thickness when the thickness is different in the lateral direction Y) of the region B facing the excretion portion of the absorbent core 40 is preferably 3 mm or more, more preferably 4 mm or more, and more preferably 10 mm or less, more preferably 8 mm or less. The thickness of the front area A and the back area C of the absorbent core 40 is preferably 1 mm or more, more preferably 2 mm or more, and more preferably 8 mm or less, and more preferably 6 mm or less.

From the viewpoint of achieving the above-mentioned effect due to the presence of the segregation of the fiber block 11 more reliably, the area of the non-skin facing surface of the absorbent core 40 located in the excretion facing region B is preferably absorbed The area of the non-skin facing surface of the sexual core 40 is 60% or less, more preferably 50% or less, and more preferably 40% or less. The portion of the absorbent core 40 located in the region B facing the excretion portion has a higher fiber mass occupancy rate than the portions located in the front region A and the rear region C, and the fiber mass occupancy rate of the non-skin facing side B2 is particularly high Therefore, the area B as a whole is also referred to as a "cushion part" that strongly reflects the cushioning properties of the fiber block 11. Particularly in this embodiment, the non-skin facing surface B2 is the main body of the fiber block 11 and contains almost no water-absorbent fiber 12F. The fiber block enrichment part 11P, therefore, the excretion facing area B with this part 11P can be Effectively functions as a buffer. That is, the above-mentioned "the ratio of the area of the non-skin facing surface of the excretory portion facing region B to the area of the non-skin facing surface of the absorbent core 40" can be said to be "the cushioning portion (fibers in the absorbent core 40). The area of the non-skin facing surface of the absorptive core 40 (the part located on the non-skin facing surface side) of the blocks 11 is concentrated relative to the area of the non-skin facing surface of the absorbent core 40 (absorbent body 4) "Ratio" (hereinafter, also referred to as "buffer area rate"). The area rate of the cushioning portion is 60% or less, that is, the area rate of the excretion portion facing area B where the fiber mass 11 is concentrated on the non-skin facing surface side B2 is less than 60%, and it is achieved in the front area A and the back area C, the effect of improving the wearing feeling of the front body or buttocks. Furthermore, from the viewpoint of surely improving the conformability of the excretion to the area B, thereby improving the wearing feeling, the lower limit of the buffer area ratio is preferably 20% or more, more preferably 25%, and more preferably More than 30%. The buffer area ratio is calculated by the following formula. Cushioning area ratio (%) = (the area of the non-skin facing surface of the cushioning part/the area of the non-skin facing surface of the absorbent core)×100

As mentioned above, the absorbent core 40 contains the water-absorbent polymer 13, and the location of the water-absorbent polymer 13 in the absorbent core 40 is not particularly limited, and it can be uniformly distributed throughout the absorbent core 40. It may be concentrated in a part of the absorbent core 40, but it is preferably present at least in the area B facing the excretion part of the absorbent core 40. Thereby, in addition to the effect (especially the effect of improving the liquid introduction property) caused by the above-mentioned segregation of the fiber mass 11, the liquid absorption can be further improved. Furthermore, if there is more water-absorbent polymer 13 on the skin-facing surface side B1 in the excretion-facing area B of the absorbent core 40 than on the non-skin-facing surface side B2, the effect is better. That is, the absorbent core 40 contains the water-absorbent polymer 13 at least in the area B facing the excretion part, and the content of the water-absorbent polymer 13 in the absorbent core 40 is preferably such that the skin-facing side B1 is less than the non-skin-facing side. There are many B2 toward the face side.

In addition, it is preferable that the non-skin facing surface side B2 of the excretion portion facing region B of the absorbent core 40 contains not only the fiber block 11 but also the water-absorbing fiber 12F and/or the water-absorbing polymer 13. With this configuration, it is easy to introduce body fluids to the non-skin-facing surface side B2, and the body fluids can be efficiently fixed to the non-skin-facing surface side B2, so that the absorbent core 40 can further improve the liquid absorption.

In this embodiment, as shown in FIG. 5, the absorptive core 40 has a protruding part that protrudes toward the skin side of the wearer (user of the absorbent body 4) of the sanitary napkin 1 from the peripheral part in the area B facing the excretion part. 15. The basis weight of the core forming material is that the raised portion 15 is larger than the peripheral portion, so the thickness is also thicker than the peripheral portion. The protruding portion 15 in this embodiment is formed at the excretion portion facing portion (excretion point) of the excretion portion facing region B, more specifically, the excretion portion facing the absorbent core 40 where the excretion portion opposing portion is located The central part in the lateral direction Y of the area B is formed to bulge convexly toward the wearer's skin side than the peripheral part. Moreover, due to the presence of raised portions 15 in the area B facing the excretion portion of the absorbent core 40, as shown in FIG. 2, the area B facing the excretion portion of the corresponding sanitary napkin 1 has a surface facing the wearer The skin side is formed as a convex convex part. In this way, there is a convex part corresponding to the raised part 15 of the absorbent core 40 on the skin facing surface of the excretory part facing area B of the sanitary napkin 1, whereby the convex part is in close contact with the excretory part of the wearer, so the wearer is wearing Sensitivity and liquid absorption can be improved. In addition, as described above, in the excretion-facing area B of the absorbent core 40 where the above-mentioned protrusions are present, the fiber blocks 11 are concentrated on the non-skin-facing surface side B2, thereby ensuring absorption at a high level. The non-folding property and the liquid introduction property of the sexual core 40 are complementary to the effect caused by the convex portion, and the wearing feeling and liquid absorption of the sanitary napkin 1 can be further improved. In addition, the protruding portion 15 may be formed over the entire length of the lateral direction Y of the excretory portion facing region B of the absorbent core 40. In addition, the protruding portion 15 may extend from the excretion portion facing area B to the front area A and/or the rear area C.

In the absorbent core 40, the content ratio of the fiber block 11 to the absorbent fiber 12F is not particularly limited, provided that the above-mentioned specific range of the fiber block occupancy rate is satisfied, as long as it is based on the constituent fibers (synthetic fiber) of the fiber block 11 The types of 11F and water-absorbent fiber 12F can be adjusted appropriately. For example, when the constituent fibers 11F of the fiber block 11 are thermoplastic fibers (non-water-absorbent synthetic fibers), and the water-absorbent fibers 12F are cellulose-based water-absorbent fibers, from the viewpoint of achieving the specific effects of the invention more reliably In other words, the content of the fiber block 11 and the water-absorbent fiber 12F is greater than the former (fiber block 11)/the latter (water-absorbent fiber 12F), preferably 20/80 to 80/20, more preferably 40/60 to 60/40.

The content of the fiber block 11 in the absorbent core 40 relative to the total mass of the absorbent core 40 in a dry state is preferably 20% by mass or more, more preferably 40% by mass or more, and more preferably 80% by mass Below, it is more preferably 60% by mass or less. The content of the absorbent fiber 12F in the absorbent core 40 relative to the total mass of the absorbent core 40 in a dry state is preferably 20% by mass or more, more preferably 40% by mass or more, and more preferably 80% by mass % Or less, more preferably 60% by mass or less. The content of the water-absorbing polymer 13 in the absorbent core 40 relative to the total mass of the absorbent core 40 in a dry state is preferably 1% by mass or more, more preferably 5% by mass or more, and more preferably 80 Mass% or less, more preferably 50 mass% or less. Furthermore, the "absorbent core in a dry state" herein refers to the absorbent core before absorbing body fluids.

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, more preferably 480 g /m ² or less. The basis weight of the 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, more preferably 480 g/m ² or less. The basis weight of the water-absorbent polymer 13 in the absorbent core 40 is preferably 5 g/m ² or more, more preferably 10 g/m ² or more, and more preferably 200 g/m ² or less, more preferably 100 g/m ² or less.

The absorbent core 40 can be manufactured in accordance with a conventional method using a known fiber stacking device equipped with a rotating drum. The fiber stacking device is typically equipped with: a rotating drum with a concavity for accumulation formed on the outer peripheral surface; and a pipe with a core forming material (fiber block 11, water-absorbent fiber 12F, water-absorbent polymer 13) The flow path that is conveyed to the concavity for accumulation; while the rotating drum is rotated along the circumference of the drum around the axis of rotation, while the suction is generated from the inner side of the rotating drum in the flow path The core-forming material conveyed by the air flow is accumulated in the accumulation recess. The fiber accumulation formed in the concavity for accumulation by this fiber accumulation step is the absorbent core 40. The specific arrangement of the core forming materials in the absorbent core 40 can be achieved by appropriately adjusting the stacking order of the core forming materials on the rotating drum in the manufacturing method using the fiber stacking device described above. 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 more preferably 800 g/m ² or less, more preferably 600 g/m ² or less.

As a method of manufacturing the absorbent body of the present invention (absorbent body in which fiber masses are concentrated in the thickness direction) of the present invention using a known fiber stacking device, for example, the following two methods can be cited. 1) A method in which two fiber stacking devices are used to superimpose and integrate a fiber stack manufactured by one fiber stacking device and a fiber stack manufactured by another fiber stacking device (hereinafter, also referred to as "the first manufacturing method") . 2) A method of using one fiber stacking device to make the supply timing of the fiber agglomerates to the accumulation recesses and the supply timing of the absorbent fibers to the accumulation recesses different (hereinafter also referred to as "the second manufacturing method").

In the above-mentioned first manufacturing method, first, water-absorbent fibers and water-absorbent polymers (if necessary) are used as core-forming materials, and the core-forming materials are accumulated in the accumulation recesses of the first fiber stacking device to produce absorbent Fiber accumulation body. The above-mentioned water-absorbent fiber accumulation body may correspond to the water-absorbent fiber-rich portion 12P of the absorbent core 40. Furthermore, a fiber block is used as a core body forming material, and the core body forming material is accumulated in the accumulation recess of the second fiber accumulation device to produce a fiber block accumulation body. The above-mentioned fiber mass accumulation body may correspond to the fiber mass enrichment part 11P of the absorbent core 40. Then, the above-mentioned water-absorbent fiber accumulation body and the above-mentioned fiber block accumulation body are overlapped to obtain a laminated body, and the laminated body is pressurized in the thickness direction to integrate the laminated body. As an integrated method different from this, a suction device like a known vacuum conveyor is used to place the above-mentioned absorbent fiber stack on the suction surface of the suction device, and the suction force on the suction surface In a functioning state, the above-mentioned fiber block stack is superimposed on the water-absorbent fiber stack to be integrated. Regardless of the integration method, entanglement of the water-absorbent fiber and the fiber block occurs at the interface between the water-absorbent fiber accumulation and the fiber block accumulation. In this way, the absorbent body of the present invention (the region B facing the excretion portion of the absorbent core 40) is obtained.

In the above-mentioned second manufacturing method, as the fiber stacking device, a portion having a different suction force of the concavity for accumulation is used. For example, as the concavity for accumulation, one having a low suction concavity and a high suction concavity having a higher suction force than the low suction concavity is used. The said low suction recessed part and the said high suction recessed part are connected in the rotation direction (circumferential direction) of the rotating drum which the fiber stacking apparatus has. In addition, the fiber stacking device of this structure is operated, while the rotating drum is rotated in the circumferential direction to convey the concavity for accumulation in one direction, the suction from the inside of the rotating drum is generated from the outside of the rotating drum The air flow toward the accumulation recessed portion, and the core-forming material is supplied to the accumulation recessed portion by the air flow to be accumulated (accumulation step). In the above-mentioned accumulation step, first, the fiber mass is supplied to the accumulation recess and accumulated. At this time, the fiber agglomerates are concentrated in the high suction recessed portion, and a fiber agglomerate stack is formed in the high suction recessed portion. Then, after the accumulation of the fiber block or in the middle of the accumulation, the water-absorbent fiber and the water-absorbent polymer (if necessary) are supplied to the accumulation recess and accumulated. At this time, the water-absorbent fibers (water-absorbent polymer) accumulate in the low suction recesses in the accumulation recesses, and also accumulate on the fiber blocks accumulated in the high suction recesses, that is, water absorption is formed in the entire area of the accumulation recesses. Sexual fiber accumulation. Furthermore, because the fiber block has air permeability, even in the state where the fiber block is accumulated in the high suction recessed portion, the suction force of the absorbent fiber that can absorb the water also acts on the accumulated fiber block, thereby enabling the Water-absorbent fibers (water-absorbent polymers) are superimposed on the fiber blocks gathered in the high suction recesses to gather them. In this way, a laminate of the fiber mass accumulation and the water-absorbent fiber accumulation is formed in the high suction recessed portion, and entanglement of the fiber mass and the water-absorbent fiber occurs at the interface between the two fiber accumulations. In this way, the absorbent body of the present invention (the region B facing the excretion portion of the absorbent core 40) is obtained.

Hereinafter, the fiber block 11 will be further described. In Fig. 6, two typical outer shapes of the fiber block 11 are shown. The fiber block 11A shown in Fig. 6(a) is formed in a quadrangular prism shape, more specifically, a rectangular parallelepiped shape, and the fiber block 11B shown in Fig. 6(b) is formed in a disc shape. The fiber blocks 11A and 11B are common in that they have two base planes 111 facing each other and a body plane 112 connecting the two base planes 111. Both the basic surface 111 and the skeleton surface 112 are parts where it is confirmed that there is substantially no unevenness in accordance with the level applied when evaluating the degree of unevenness on the surface of the fiber-based article.

The rectangular parallelepiped fiber block 11A in Fig. 6(a) has 6 flat surfaces. Among the 6 surfaces, the two opposite surfaces with the largest area are the basic surface 111, and the remaining four surfaces are the skeleton surface 112. The fundamental plane 111 and the skeleton plane 112 intersect each other, and more specifically, are orthogonal to each other. The disc-shaped fiber block 11B of Fig. 6(b) has two flat surfaces facing each other circular in plan view, and a curved peripheral surface connecting the two flat surfaces. The two flat surfaces are the basic surface 111, respectively. The peripheral surface is the skeleton surface 112. The fiber blocks 11A and 11B have a quadrangular shape in a plan view of the skeleton surface 112, and more specifically, they have a rectangular shape in common.

The plurality of fiber blocks 11 contained in the absorbent core 40 are respectively the fiber blocks 11A and 11B shown in FIG. 6 having two opposing basic planes 111 and a skeleton plane 112 connecting the two basic planes 111. Shaped fiber assembly"; in this respect, it is different from the amorphous fiber assembly in the above-mentioned prior art. In other words, when any one fiber block 11 in the absorbent core 40 is seen through (for example, in the case of observation with an electron microscope), the see-through shape of the fiber block 11 is different depending on its viewing angle. The fiber block 11 has a plurality of see-through shapes, and the plurality of fiber blocks 11 in the absorbent core 40 respectively have a specific see-through shape having two opposing basic planes 111 and a skeleton plane 112 connecting the two basic planes 111 as each One of many perspective shapes. The above-mentioned indefinite fiber aggregates in the prior art do not substantially have a "face" like the basic plane 111 or the skeleton plane 112, that is, the part with diffusion, and the external shapes are different from each other, and they are not "fixed".

In this way, if the plurality of fiber blocks 11 included in the absorbent core 40 is a "fixed fiber assembly" formed by dividing the basic plane 111 and the skeleton plane 112, it is compared with the case of an indefinite fiber assembly. The uniform dispersibility of the fiber block 11 in the absorbent core 40 is improved, so the effect that can be expected by combining the fiber assembly like the fiber block 11 in the absorbent core 40 is more stable (improving the absorbent core Softness, cushioning, compression recovery, etc.). Moreover, especially in the case of the rectangular parallelepiped fiber block 11 as shown in Fig. 6(a), its outer surface is composed of two basic planes 111 and four skeleton planes 112, a total of 6 planes, so it can be relatively large The ground has the opportunity of contact with other fiber blocks 11 or water-absorbent fibers 12F, so that the entanglement property is improved, and the shape retention property is also improved.

In the fiber block 11, the total area of the two basic surfaces 111 is preferably greater than the total area of the skeleton surface 112. That is, in the cuboid-shaped fiber block 11A of Fig. 6(a), the sum of the respective areas of the two basic planes 111 is greater than the sum of the respective areas of the four skeleton planes 112, and the disc in Fig. 6(b) In the fiber block 11B of the shape, the sum of the respective areas of the two basic surfaces 111 is greater than the area of the skeleton surface 112 forming the peripheral surface of the fiber block 11B in the disc shape. In any of the fiber blocks 11A and 11B, the basic surface 111 is the surface with the largest area among the plurality of surfaces of the fiber blocks 11A and 11B.

The fiber block 11, which is divided by two basic planes 111 and a skeleton plane 112 intersecting the two basic planes 111, is manufactured by a manufacturing method different from the prior art. A preferable manufacturing method of the fiber block 11 has the following steps: As shown in FIG. 7, a cutting device such as a cutter is used to cut the raw fiber sheet 10bs as a raw material in a fixed shape. The raw fiber sheet 10bs is a sheet having the same composition as the fiber block 11 and larger in size than the fiber block 11, and is preferably a non-woven fabric. The shapes and sizes of the plurality of fiber blocks 11 manufactured through this step are more uniform in shape and size than the indefinite fiber assembly manufactured by the prior art. Fig. 7 is a diagram for explaining the method of manufacturing the rectangular parallelepiped fiber block 11A of Fig. 6(a), and the broken line in Fig. 7 represents 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 in such a manner are combined.

As shown in FIG. 7, the rectangular parallelepiped fiber block 11A of FIG. 6(a) is formed by placing the raw fiber sheet 10bs along the first direction D1 and crossing the first direction D1 (more specifically, orthogonal ) The second direction D2 is cut to a specific length and manufactured. The two directions D1 and D2 are respectively specific one direction in the plane direction of the sheet 10bs, and the sheet 10bs is cut along the thickness direction Z orthogonal to the plane direction. In this way, in a plurality of rectangular parallelepiped fiber blocks 11A obtained by cutting the raw fiber sheet 10bs in a so-called small square shape, usually, the cut surface, that is, when the sheet 10bs is cut, is combined with a cutting device such as a cutter The contact surface 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 (a surface orthogonal to the thickness direction Z) of the sheet 10bs, and, as described above, is the surface with the largest area among the plural surfaces of the fiber block 11A.

Furthermore, the above description of the fiber block 11A is basically applicable to the disc-shaped fiber block 11B of FIG. 6(b). The essential difference from the fiber block 11A is only the cutting pattern of the raw fiber sheet 10bs. When the sheet 10bs is cut in a fixed shape to obtain the fiber block 11B, the sheet 10bs needs to be rounded according to the top view shape of the fiber block 11B. The shape is cut off.

In addition, the outer shape of the fiber block 11 is not limited to that shown in FIG. 6. The basic surface 111 and the skeleton surface 112 may be flat surfaces without bending like the surfaces 111 and 112 in FIG. 6(a), or may be The skeleton surface 112 (the peripheral surface of the disc-shaped fiber block 11B) in Fig. 6(b) is a curved surface. Furthermore, the basic surface 111 and the skeleton surface 112 may also have the same shape and size. Specifically, for example, the outer shape of the fiber block 11A may also be a cubic shape.

The size of the fiber block 11 is not particularly limited, and can be appropriately set in consideration of the cushioning properties and liquid permeability of the absorbent core 40. The area of the fundamental plane 111, which is the largest in the plurality of surfaces of the fiber block 11, can be an indicator of the size of the fiber block 11. The area of the basic surface 111 of the fiber block 11 is preferably 1 mm ² or more, more preferably 5 mm ² or more, and more preferably 100 mm ² or less, and more preferably 50 mm ² or less.

As a preferable fiber block 11, the aspect ratio of the basic plane 111 is 1 or close to 1, that is, the plane shape of the basic plane 111 is a square or a shape imitating a square. If the fiber block 11 is used in the absorbent core 40, the absorbent core 40 tends to become bulky, and the cushioning properties can be improved.

Regarding the aspect ratio of the basic plane 111, when the planar shape of the basic plane 111 is a quadrangle, it is calculated by the ratio of the lengths of the two orthogonal sides that divide the basic plane 111 forming the quadrangle. If the lengths of the two sides are the same, the aspect ratio of the basic plane 111 of the quadrangular shape when viewed from above is 1. When the lengths of the two sides are different from each other, the top view shape of the basic plane 111 is as shown in Figure 6(a) In the case of a rectangular shape, it is calculated by the ratio (L2/L1) of the length L2 of the long side 111b to the length L1 of the short side 111a. Also, as in the fiber block 11B shown in Fig. 6(b), when the planar shape of the basic plane 111 is not a quadrangular shape, the length of the two orthogonal axes passing through the center (center of gravity) of the basic plane 111 The ratio is calculated. If the lengths of the two shafts are the same, the aspect ratio of the basic plane 111 of the non-tetragonal shape when viewed from above is 1. When the lengths of the two shafts are different from each other, there is a short shaft with a relatively short length and a relatively long length In the case of the long long axis, it is calculated as the ratio of the length of the long axis (the length shown by the symbol L2 in Figure 6(b)) to the length of the short axis (the former/the latter).

The size etc. of each part of the fiber block 11 (11A, 11B) can be set as follows, for example. The size of each part of the fiber block 11 can be measured based on the electron micrograph of the fiber block 11 or the like. When the basic plane 111 is a rectangular shape in plan view as shown in FIG. 6(a), the length L1 of the short side 111a is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more, Moreover, it is preferably 10 mm or less, more preferably 6 mm or less, and still more preferably 5 mm or less. The length L2 of the long side 111b of the rectangular basic plane 111 in plan view is preferably 0.3 mm or more, more preferably 1 mm or more, still more preferably 2 mm or more, and preferably 30 mm or less, more preferably 15 mm Below, it is more preferably 10 mm or less. Furthermore, as shown in FIG. 6, when the basic plane 111 is the surface with the largest area among the plural faces of the fiber block 11, the length L2 of the long side 111b and the maximum diameter of the fiber block 11 (the long axis The length) is the same, and the maximum diameter is the same as the diameter of the circular basic plane 111 in the plan view of the disc-shaped fiber block 11B. The thickness T of the fiber block 11, that is, the length T between the two opposing basic surfaces 111, is preferably 0.1 mm or more, more preferably 0.3 mm or more, and more preferably 10 mm or less, more preferably 6 mm or less.

As mentioned above, the two types of surfaces (basic surface 111, skeleton surface 112) of the fiber block 11 (11A, 11B) are divided into: cut surface (skeleton surface 112), which is obtained by using a cutting machine when manufacturing the fiber block 11 The cutting device cuts the raw fiber sheet 10bs and is formed; and the non-cutting surface (the basic surface 111) is the original surface of the sheet 10bs and is not in contact with the cutting device. Furthermore, due to the difference in whether the cut surface is the same, the skeleton surface 112 as the cut surface has a feature that the number of fiber ends per unit area is larger than that of the basic surface 111 as the non-cut surface. The "fiber end" here means the end of the fiber 11F constituting the fiber block 11 in the longitudinal direction. Normally, there are fiber ends on the basic plane 111 which is a non-cut surface, but since the skeleton surface 112 is a cut surface formed by cutting the raw fiber sheet 10bs, it includes the cut surface formed by the cutting Most of the fiber ends constituting the cut ends of the fiber 11F are present in the entire skeleton surface 112, that is, the number of fiber ends per unit area is more than the basic surface 111.

The fiber ends existing on each side of the fiber block 11 (basic plane 111, skeleton surface 112) are useful for forming entanglements between the fiber block 11 and other fiber blocks 11 or water-absorbent fibers 12F contained 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, and therefore the shape retention properties of the absorbent core 40 can be improved. Moreover, as described above, the number of fiber ends per unit area in each surface of the fiber block 11 is not equal, and the number of fiber ends per unit area is the size relationship of "skeleton surface 112> basic surface 111" Established, therefore, the entanglement between the fiber block 11 and other fibers (other fiber blocks 11, water-absorbent fibers 12F) is different on different faces of the fiber block 11, and the entanglement system skeleton surface 112 is higher than the basic surface 111. That is, the bonding force achieved by the interlacing of the frame surface 112 with other fibers is stronger than that achieved by the interlacing of the basic surface 111 with other fibers. In one fiber block 11, the basic surface 111 and the frame surface 112 are in contact with each other. The bonding strength of other fibers will be poor. Generally speaking, the stronger the binding force, the more restricted the freedom of movement of the combined fibers, and the overall strength (shape retention) of the absorbent core 40 tends to increase but the softness decreases.

In this way, in the absorbent core 40, the plurality of fiber blocks 11 contained therein respectively have two binding forces with respect to other fibers (other fiber blocks 11, water-absorbent fibers 12F) around the core body 40. The core 40 has both moderate softness and strength (shape retention). Moreover, when the absorbent core 40 having such excellent characteristics is used as an absorbent body of an absorbent article in accordance with the common law, it can provide the wearer of the absorbent article with a comfortable wearing feeling, and can effectively Prevent the absorbent core 40 from being damaged by external forces such as the wearer's body pressure during wearing.

In particular, as described above, in the fiber block 11 (11A, 11B) shown in FIG. 6, the total area of the two basic surfaces 111 is greater than the total area of the skeleton surface 112. 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 intertwinability with other fibers is larger than the skeleton plane 112 with the opposite property. Therefore, the fiber block 11 (11A, 11B) shown in Fig. 6 is easier to entangle with other fibers (other fiber blocks 11, water-absorbent fibers 12F) around the fiber block than the fiber block with fiber ends uniformly existing on the entire surface. It is suppressed, and even if it is entangled with other fibers in the surrounding, it is easy to entangle with relatively weak binding force, so it is difficult to become a large agglomerate, so that excellent flexibility can be imparted to the absorbent core 40.

The constituent fibers 11F of the fiber block 11 include synthetic fibers. The synthetic fiber used as the fiber 11F is preferably one having lower water absorption than the water-absorbent fiber 12F (weak water absorption), and particularly preferably a non-absorbent synthetic fiber. The constituent fibers 11F of the fiber block 11 may contain fiber components other than synthetic fibers (for example, natural fibers), but the constituent fibers 11F of the fiber block 11 include weakly hydrophilic fibers, preferably non-absorbent fibers, and are not only absorbent When the core 40 is in a dry state, when it absorbs water (urine or menstrual blood and other body fluids) and is in a wet state, it also stably achieves the effect of the above-mentioned fiber block 11 (improving shape retention) , Softness, cushioning, compression recovery, not easy to crease, etc.). The content of the synthetic fibers as constituent fibers 11F in the fiber block 11 is preferably 90% by mass or more, and most preferably 100% by mass relative to the total mass of the fiber block 11, that is, the fiber block 11 is formed only of synthetic fibers. Especially when the synthetic fiber constituting the fiber 11F is non-water-absorbing, the effect due to the existence of the fiber block 11 can be achieved more stably.

In this specification, the term "water absorption" is, for example, something that can be easily understood by the industry as the saying that pulp is water-absorbing. Similarly, the statement that thermoplastic fibers have weak water absorption (especially non-water absorption) can be easily understood. On the one hand, the degree of water absorption of the fiber can be compared with the relative difference in water absorption by using the value of the moisture content measured by the following method, and a better range can be specified. The greater the value of the moisture content, the stronger the water absorption of the fiber. As the water-absorbing fiber, the moisture content is preferably 6% or more, more preferably 10% or more. On the other hand, the moisture content of synthetic fibers is preferably less than 6%, and more preferably less than 4%. Furthermore, when the moisture content is less than 6%, it can be determined that the fiber is a non-absorbent fiber.

＜Measuring method of moisture content＞ The moisture content is calculated using the moisture content test method of JIS P8203. That is, after the fiber sample is allowed to stand for 24 hours in a laboratory at a temperature of 40° C. and a relative humidity of 80% RH, the weight W (g) of the fiber sample before the absolute drying treatment is measured in the chamber. After that, it is allowed 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 treatment of the fiber sample. After absolute drying treatment, in a standard laboratory at a temperature of 20±2℃ and a relative temperature of 65±2%, the fiber sample is embedded in the Saran Wrap (registered trademark) manufactured by Asahi Kasei (Co., Ltd.). Si silicone rubber (for example, Toyota Chemical Co., Ltd.) is put into a glass desiccator (for example, manufactured by Tech jam (Co., Ltd.)), and left to stand until the fiber sample reaches a temperature of 20±2°C. Thereafter, the constant weight W'(g) of the fiber sample is weighed, and the moisture content of the fiber sample is obtained by the following formula. Moisture rate (%) = (W－W'/W')×100

Also, similarly, from the viewpoint that the absorbent core 40 can exhibit excellent effects such as shape retention, flexibility, cushioning, compression recovery, and resistance to crease regardless of whether it is in a dry state or a wet state. In other words, the fiber block 11 preferably has a three-dimensional structure formed by fusing a plurality of thermoplastic fibers with each other.

In order to obtain a fiber block 11 with a plurality of three-dimensionally dispersed hot-melt portions, the raw fiber sheet 10bs (refer to FIG. 7) may be constructed in the same manner. In addition, as described above, such a plurality of three-dimensionally dispersed raw fiber The sheet 10bs can be manufactured by performing heat treatment such as hot air treatment on a web or nonwoven fabric mainly composed of thermoplastic fibers.

Examples of non-water-absorbing synthetic resins (thermoplastic resins) suitable for use as the material of the fibers 11F of the fiber block 11 include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; Polyamides such as nylon 6, nylon 66; polyacrylic acid; polyalkyl methacrylate; polyvinyl chloride; polyvinylidene chloride, etc.; one of them can be used alone or two or more of them can be used in combination. Furthermore, the fiber 11F may be a single fiber composed of a blend polymer obtained by mixing one type of synthetic resin (thermoplastic resin) or two or more types of synthetic resins, or may be a composite fiber. The composite fiber here refers to a synthetic fiber (thermoplastic fiber) obtained by combining two or more synthetic resins with different components in a spinning head and spinning them at the same time. The structure is such that plural components are continuous in the length direction of the fiber. , And adhere to each other in the single fiber. The form of the composite fiber includes core-sheath type, side-by-side type, etc., and is not particularly limited.

In addition, from the viewpoint of further improving the introduction of body fluids initially excreted, the contact angle of the fiber block 11 with water is preferably less than 90 degrees, more preferably 70 degrees or less. Such fibers are obtained by treating the above-mentioned non-water-absorbing synthetic fibers with a hydrophilizing agent in accordance with a conventional method. As the hydrophilizing agent, a usual surfactant can be used.

＜Method of measuring contact angle＞ The fiber was taken out from the measurement object (absorbent core), and the contact angle between water and the fiber was measured. The automatic contact angle meter MCA-J manufactured by Concord Interface Science Co., Ltd. was used as the measuring device. The contact angle was measured using deionized water. The amount of liquid ejected from the inkjet water droplet ejection unit (Cluster Technology Co., Ltd., pulse jet CTC-25 with an aperture of 25 μm) was set to 20 picoliters, and the water droplets were dropped directly above the fiber. Record the dripping conditions to a high-speed recording device connected to a horizontally set camera. From the point of view that the video recording device performs image analysis from the later stage, it is more ideal to be a personal computer incorporating a high-speed capture device. In this measurement, an image is recorded every 17 msec. In the captured images, use the attached software FAMAS (software version is 2.6.2, the analysis method is the droplet method, the analysis method is the θ/2 method, the image processing algorithm is no reflection, the image processing image mode It is a picture frame, the threshold level is 200, no curvature correction is performed) The original image of the water droplet on the fiber is image analyzed, and the angle between the surface of the water droplet in contact with the air and the fiber is calculated, and this is taken as the contact angle . The fiber taken out from the measurement object is cut to a fiber length of 1 mm, and the fiber is placed on the sample table of the contact angle meter and kept horizontal. Each fiber measures the contact angle of two different parts. Measure the contact angle of N=5 and be accurate to 1 decimal place, and the value obtained by averaging the measured values of 10 locations (rounded to 2 decimal places) is defined as the contact angle of the fiber and water. The measurement environment is room temperature 22±2℃, humidity 65±2%RH.

In addition, the absorber (absorbent core) to be measured is used as a constituent member of other articles such as absorbent articles. When the absorber is taken out for evaluation and measurement, if the absorber uses an adhesive, For fixing to other components by means of fusion, etc., within the range that does not affect the contact angle of the fiber, use methods such as blowing cold air to release the adhesive force, and then take out the fixed part. This step is common to all measurements in this application specification.

As mentioned above, although this invention was demonstrated based on the embodiment, this invention is not limited to the said embodiment, and can change suitably. For example, in the above embodiment, the absorber 4 has a thick structure in which the thickness of at least the central part of the lateral Y of the excretion-facing area B is greater than that of the other areas A and C. However, the thickness of the absorber 4 may also be at the excretion The facing area B is the same as the front and rear areas A and C. In this case, for example, the overall thickness of the absorbent body 4 can be produced according to the following method: firstly produce an absorbent core 40 of uniform thickness, and then oppose the excretory part of the absorbent core 40 of uniform thickness At least a part of the forming material of the area B is eliminated, and then the fiber block 11 of the eliminated thickness portion is immediately added. The absorbent article of the present invention broadly includes articles for absorbing body fluids (urine, soft stools, menstrual blood, sweat, etc.) discharged from the human body. In addition to the menstrual sanitary napkins mentioned above, it also includes sanitary shorts, so-called unfolding type with adhesive tape Disposable diapers, shorts-type disposable diapers, incontinence pads, etc. Example

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

[Example 1] The absorbent body 4 shown in FIGS. 3 to 5 was manufactured, and this was used as the absorbent body of Example 1. Specifically, the fiber block 11, the water-absorbent fiber 12F, and the water-absorbent polymer 13 are used as core-forming materials, and two known fiber stacking devices are used to separately stack them according to a conventional method to produce the water-absorbent fiber-enriched parts 12P and The fiber mass-enriched part 11P overlaps the water-absorbent fiber-enriched parts 12P and the fiber mass-enriched part 11P and pressurizes them along the thickness direction to obtain an absorbent core 40 with a basis weight as The 16 g/m ² core-clad material 41 covers the entire outer surface of the absorbent core 40 to produce the absorbent body 4. The production of the fiber block 11 is performed by cutting the raw fiber sheet into small squares according to FIG. 7. Use non-absorbent thermoplastic fiber composed of polyethylene resin fiber and polyethylene terephthalate resin fiber (non-absorbent fiber, fiber diameter of 18 μm) as the constituent fiber, with a basis weight of 18 g/m ² , Hot-air non-woven fabric (fiber sheet with hot-melt parts constituting fibers) with a thickness of 0.6 mm is used as the raw fiber sheet for the fiber block. Conifer sun-dried kraft pulp (NBKP) was used as the absorbent fiber 12F. As the water-absorbent polymer 13, a partial sodium salt of poly(acrylic acid) is used.

In the absorbent body 4 of Example 1, the longitudinal length is 210 mm, and the lateral length is 70 mm. The lateral length extends across the longitudinal direction of the absorbent body 4 except for the front and rear ends of the longitudinal X which are part of the front area A and the rear area C The length is fixed. The thickness of the absorbent body 4 of Example 1 is 3.2 mm for the front area A and the rear area C, respectively, and the excretion facing area B is 5.7 mm. The excretion facing area B has a side toward the skin of the user than the peripheral portion The uplift of the uplift. In addition, in the absorbent core 40 of Example 1, the entire non-skin-facing surface side B2 of the excretory portion facing region B is the fiber block-rich site 11P (the fiber block occupancy rate is 100% by mass). All the other parts are water-absorbent fiber-enriched part 12P (the fiber block occupancy rate is 0.01% by mass, and the water-absorbent fiber occupancy rate is 99.9% by mass). The front area A (absorbent fiber-rich site 12P) The longitudinal length is 55 mm, the longitudinal length of the excretion area B (fiber enrichment part 11P) is 80 mm, and the longitudinal length of the rear area C (absorbent fiber enrichment 12P) is 75 mm. In addition, the buffer area ratio of the absorbent body 4 of Example 1 (the ratio of the area of the non-skin facing surface of the excretory portion facing region B to the total area of the non-skin facing surface of the absorbent body) was 38.6 %. The basis weight of the fiber block of the absorbent core 40 of Example 1 is 140 g/m ² , and the basis weight of the water-absorbent fiber is 210 g/m ² . Furthermore, in the absorbent core 40 of Example 1, 50 g/m ^{2 of the} water-absorbent polymer 13 is contained, and 90% by mass or more thereof is contained in the water-absorbent fiber-rich portion 12P. In addition, at the interface between the fiber block-enriched part 11P and the water-absorbent fiber-enriched part 12P, there is an entanglement of the fiber block 11 and the water-absorbent fiber 12F, but outside the interface and its vicinity, the fiber block layer 11P does not contain water absorption The sex fiber 12F, the water-absorbent fiber layer 12P does not contain the fiber block 11. The above-mentioned "fiber block occupancy rate" is the value of the part outside the interface area.

[Comparative Example 1] A laminate in which an elastic cushion sheet was laminated on the non-skin facing side with the absorbent core and the absorbing elements of the core-covered material was produced, and this was used as the absorbent of Comparative Example 1. The thickness of the absorber of Comparative Example 1 was uniformly 5.7 mm. The absorbent element of Comparative Example 1 has the same basic structure as the absorbent body of Example 1, except that the absorbent core does not contain fiber blocks. Use a sheet-like hot-air non-woven fabric with the same shape and size as the absorption element when viewed from the top, and a basis weight of 40 g/m ² as the buffer sheet, overlap and fix the 3 buffer sheets on the non-skin facing surface of the absorption element And make the buffer. The buffer sheet is fixed by covering the entire area of the non-skin facing surface of the absorbing element. For the fixing of the buffer sheets and between the buffer sheet and the absorbing element, a hot melt adhesive is used. In the absorbent body of Comparative Example 1, the entire area of the non-skin facing surface of the absorbent body is formed as a buffer part, so the above-mentioned buffer part area ratio is 100%. The basis weight of the absorbent fiber is 210 g/m ² .

[Comparative Example 2] An absorbent body of Comparative Example 2 having the same constitution as that of the absorbent element of Comparative Example 1 was produced. The thickness of the absorber of Comparative Example 2 was uniformly 5.7 mm. The basis weight of the absorbent fiber is 350 g/m ² .

〔Performance evaluation〕 Regarding the absorbers of the respective Examples and Comparative Examples, the dynamic crease rate, the ring crush rate, the bending rigidity, the dynamic maximum absorption, the compression strain rate, and the recovery work amount were respectively measured by the following methods. The results are shown in Table 1 below.

Furthermore, when an absorbent article is used as a measurement object, the absorbent bodies of the respective examples and comparative examples are used to produce a menstrual sanitary napkin with the same basic structure as the sanitary napkin 1 shown in FIG. 1, and use the menstrual sanitary napkin于定。 To determine. The hot-air non-woven fabric with a basis weight of 30 g/m ² is used as the front sheet of menstrual sanitary napkins, and a 37 g/m ² polyethylene resin film (FL-KDJ100nN, manufactured by Dahua Industrial) is used as the back sheet.

＜Measurement method of dynamic fold rate＞ The menstrual sanitary napkin was used as the measurement sample, and the driven female lower body mannequin was used to evaluate the dynamic fold rate of the measurement sample. First, measure the central width of the sanitary napkin (the horizontal length of the longitudinal center of the sanitary napkin) (the central width before walking) of the sanitary napkin of the measuring object, stick the sanitary napkin on the shorts and install it on the female mannequin. Secondly, the mannequin was walked for 30 minutes at a speed of 100 steps/min. During the walking process of the mannequin, walk 6 times for 3 minutes and then inject 1.5 g of defibrinated horse blood into the sanitary napkin in the installed state for 15 seconds For the operation, a total of 9 g of defibrinated horse blood was injected into the sanitary napkin. Then, remove the sanitary napkin from the shorts and measure its central width (central width after walking). From the central width before walking and the central width after walking, the dynamic pleating rate (%) is calculated by the following formula. The smaller the value of the dynamic pleating rate, the less prone the sanitary napkin is to pleating, so the evaluation is higher. Furthermore, the defibrinated horse blood injected into the measurement object is the defiberized horse blood manufactured by Japan Bioassay Co., Ltd., and the viscosity of the liquid temperature at 25°C has been adjusted to 8 cp, and its viscosity It uses the TVB-10M viscometer manufactured by Toki Industry Co., Ltd., and the viscosity of the rotor with the rotor name L/AdP (rotor number 19) is measured at a rotation speed of 12 rpm. Dynamic pleating rate (%) = [{(central width before walking)-(central width after walking)}/(central width before walking)]×100

＜Measuring method of ring crushing rate＞ According to the following (Method for preparing absorbent articles with absorbent body in a wet state), make the absorbent body of the measurement object in a wet state, and make the absorbent body in the wet state face the absorbent body's skin (menstrual sanitary napkin) The facing surface opposite to the front sheet) is bent along the length direction (longitudinal direction) so that it becomes the inside, and the two ends of the length direction are fixed to each other with a stapler to make a ring with a diameter of 45 mm Measure the sample. Using the small desktop testing machine EZTest (EZ-L) manufactured by Shimadzu Corporation, the ring-shaped measurement sample is installed on the test bench so that the axial direction of the ring is orthogonal to the measurement sample placement surface of the test bench. At a compression speed of 120 mm/min, repeatedly compress the measurement sample 3 times until the distance between the compression device of the measurement sample and the measurement sample placement surface becomes 30 mm, and measure the height after compression. From the height of the sample before compression and the height of the sample after compression, the ring crushing rate (%) is calculated by the following formula. The smaller the value of the ring breakage rate, the less likely the absorbent body is to wrinkle when the absorbent article is worn, so the evaluation is higher. Ring crushing rate (%) = [{(height before compression)-(height after compression)}/(height before compression)]×100

＜Measurement method of bending rigidity＞ The menstrual sanitary napkin was used as a measurement sample, and a texture testing machine (softness tester method, model HOM-3) manufactured by Daei Scientific Precision Manufacturing Co., Ltd. was used for evaluation. First, on the sample table where the slit width is set to 40 mm, the length direction (longitudinal) of the menstrual sanitary napkin is set at right angles to the blade. Place the measurement sample on the sample table in such a way that the measurement part of the measurement sample for bending rigidity overlaps the slit position of the sample table. When measuring the bending rigidity of the area in front of the menstrual sanitary napkin, the position that is 35 mm away from the longitudinal end of the front area (the front end of the sanitary napkin) to the longitudinal inner side is used as the measurement site, after the menstrual sanitary napkin is measured In the case of the bending rigidity of the area, the position that is offset from the longitudinal end of the rear area (the end of the sanitary napkin) to the longitudinal inner side by 35 mm is used as the measurement site, and the bending rigidity of the area facing the excretory part of the menstrual sanitary napkin is measured. In this case, the longitudinal center of the area facing the excretion part is used as the measurement site. Next, the blade that is set to be lowered up to 10 mm from the surface of the sample table is lowered to press the measurement sample, and the peak value (mN) at this time is used as the value of the bending stiffness of the measurement sample. The smaller the value of the flexural rigidity, the better the wearing feeling is judged to be the absorbent article incorporating the absorbent body, and the higher the evaluation.

＜Measurement method of dynamic maximum absorption capacity＞ Fix the menstrual napkin of the measuring object to the shorts for physiological use and install it on the dynamic model of the human body. A movable female waist model capable of walking with two feet is used as a dynamic model of the human body. The dynamic model was started to walk. One minute after the start of the walk, 2 g of simulated blood was injected from the fluid discharge point (first time). Furthermore, 3 minutes after the completion of the first liquid injection, 3 g of simulated blood was injected (second time). Furthermore, 3 minutes after the completion of the second liquid injection, 2 g of simulated blood was injected (third time). After the third time, repeat the operation of injecting 2 g of simulated blood after 3 minutes of injecting liquid, and end the liquid injection operation at the time when the simulated blood faints from the wings of the menstrual sanitary napkin, and the total amount of simulated blood injected up to this time The weight is taken as the dynamic maximum absorption (g). Use the following simulated blood: the viscosity measured by using a B-type viscometer (manufactured by Toki Industry Co., Ltd., model TVB-10M, measurement conditions: rotor No. 19, 30 rpm, 25°C, 60 seconds) is 8 The mPa·s method is used to prepare the blood cell/plasma ratio of defibrinated horse blood (manufactured by Japan Bioassay Laboratory Co., Ltd.). The larger the value of the dynamic maximum absorption, the easier it is for body fluids to migrate to the absorber without leaking, so the evaluation is higher.

<Method for measuring compressive strain rate (ΔT/T0)> The compressive strain rate (ΔT/T0) of the sample can be measured using KES. Specifically, the compression strain rate (ΔT/T0) was measured using an automated compression test device KES-G5 manufactured by Jiaduo Technology Co., Ltd. The measurement procedure is as follows. According to the following (Method for preparing absorbent articles with absorbent body in a wet state), the absorbent body of the measurement object is brought into a wet state. Install the sample on the test bench of the compression test device. Next, place the sample between steel plates with a circular plane with an area of 2 cm ² and compress, and the load during the compression is gradually increased, and the time point when the load reaches a specific maximum value (maximum load) is measured. The thickness of the object (compressed thickness) Tm. Be careful not to wrinkle or bend the measurement object. The measurement conditions of the compression tester are as follows.・Compression speed: 0.2 mm/sec ・Maximum load: 2450 mN/cm ²・SENS: 10 ・DEF: 20 Also, the initial thickness (T0) of the object to be measured is the thickness at the point when the above load reaches 103.9 mN/cm ² . Calculate the compressive strain rate (%) by the following formula. Compressive strain rate (ΔT/T0)={(T0－Tm)/T0)}×100

<Measurement method of compression work volume and recovery work volume> It is well known that the recovery work volume (hereinafter, also referred to as "WC'") of the measuring object (absorbent) can be obtained by KES (Kawabata) manufactured by Kado Technology Co., Ltd. (Reference: Standardization and Analysis of Texture Evaluation (Second Edition), Kawabata Yoshio, published on July 10, 1980). Specifically, the compression tester KES-G5 manufactured by Jiaduo Technology Co., Ltd. can be used to measure WC'. The measurement procedure is as follows. Furthermore, when measuring WC', it can also be measured together with the amount of compression work (hereinafter, also referred to as "WC"), so the measuring methods of WC and WC' are described together below. Prepare a 240 mm×70 mm top-view quadrangular sample (absorbent body wrapped in chip material), and install it on the test bench of the compression test device. According to the following (Method for preparing absorbent article with absorbent body in a wet state), the absorbent body is brought into a wet state to prepare a measurement sample. Secondly, the non-recessed part of the measurement sample, that is, the part that has not been subjected to rolling processing, but retains the original appearance of the measurement sample, is placed between steel plates with a circular plane with an area of 2 cm ² for compression. In this compression step, the compression speed is 0.2 cm/sec, and the maximum compression load is 2450 mN/cm ² . The recovery process is also measured at the same speed. WC is represented by the following formula (1), WC' is represented by the following formula (2), and the unit is "mN·cm/cm ² ". In the following formula, Tm represents the thickness under a load of 2450 mN/cm ² (4.9 kPa), and TO represents the thickness under a load of 4.902 mN/cm ² (49 Pa). Further, the following expression P _a, and the following formula (2) (1) of the P _b respectively represent the measurement of the compression process when a load (mN / cm ^2), and recovery of the process when the measured load (mN / cm ² ).

[Numerical formula 1]

[Numerical formula 2]

Furthermore, WC' is not displayed on the measurement result screen of KES-G5. The one displayed on the measurement result screen is the compression recovery rate or compression rebound rate calculated from WC and WC' (hereinafter, also referred to as "RC") . In this case, use the parameters (WC, RC) displayed on the measuring device to calculate WC' by the following formula.

[Equation 3]

(Preparation method of absorbent article with absorbent body in wet state) Place the absorbent article before the injection of defiberized horse blood in an environment with a temperature of 23°C and a relative humidity of 50 RH% for 24 hours to prepare an absorbent article in a dry state. The absorbent article in the dry state is placed horizontally so that the front sheet side (the side facing the skin) becomes the upper side, and an oval injection port (the long diameter is 50 mm, the short diameter is 23 m) is placed on the front sheet ), inject 3.0 g of defibrinated horse blood from the injection port, and then inject 3.0 g of defibrinated horse blood after standing for 1 minute, and maintain this state for 1 minute after injection, so as to obtain an absorbent article with a moist absorbent body. Furthermore, the defibrinated horse blood injected into the absorbent article is the defiberized horse blood manufactured by Japan Bioassay Co., Ltd., and the viscosity of the liquid temperature at 25°C has been adjusted to 8 cp, and its viscosity It uses the TVB-10M type viscometer manufactured by Toki Industry Co., Ltd., and the viscosity of the rotor with the rotor name L/Adp (rotor number 19) is measured at a rotation speed of 12 rpm.

[Table 1] Example Comparative example 1 1 2 Thickness of absorbent article (mm) Front area and back area 4.2 6.4 6.7 Opposite area of excretion 8.1 Thickness of absorber (mm) Front area and back area 3.2 5.7 5.7 Opposite area of excretion 5.7 Occupancy rate of fiber block of absorber ^{* 1} (mass%) Front area and back area 0.01 0 0 The skin opposite side of the area facing the excretion 0.01 0 0 The non-skin facing side of the area facing the excretion 100 0 0 Area rate of the buffer area of the absorber (%) ^*2 36 100 0 Evaluation Dynamic pleating rate (%) 18 twenty two 37 Ring crushing rate (%) ^*3 twenty two 26 35 Bending rigidity (mN) Front area and back area 970 1019 1695 Opposite area of excretion 618 981 1559 Dynamic maximum absorption (g) 19 17 15 Compressive strain rate [ΔT/T ₀ ](%) ^*3 67 53 42 Recovered work amount [WC'](mN•cm/cm ² ) ^*3 156.8 68.6 39.2 *1: Calculated by {the content of fiber mass/(the content of fiber mass + the content of absorbent fiber)}×100. *2: Calculated by (the area of the non-skin facing surface of the absorber buffer/the area of the non-skin facing surface of the absorber)×100. In Example 1, the entire area facing the excretion portion where the fiber masses in the absorbent body are concentrated is used as the buffer portion. *3: The measurement object (absorbent) is the measured value in a wet state. Industrial availability

The absorbent article of the present invention has excellent wearing feeling and absorption performance before and after excretion.

1: Sanitary napkin 2: Front sheet 3: Back sheet 4: Absorber 5: Absorbent body 5W: Wing 6: Side sheet 10bs: raw fiber sheet 11: Fiber block 11A: Fiber block 11B: Fiber block 11F: Constituent fiber (fiber) 11P: Fiber block enrichment part (fiber block layer) 12F: Absorbent fiber 12P: Absorbent fiber enriched part (absorbent fiber layer) 13: Water-absorbing polymer 15: Uplift 40: Absorbent core 41: package chip material 111: Fundamentals 111a: short side 111b: Long side 112: Skeleton surface A: Front area B: The area facing the excretion B1: The opposite side of the skin of the absorber B2: Non-skin facing side of the absorber C: Rear area D1: 1st direction D2: 2nd direction L1: length L2: length T: thickness X: portrait Y: horizontal Z: thickness direction

Fig. 1 is a plan view schematically showing that the skin facing side (front sheet side) of a menstrual sanitary napkin as an embodiment of the absorbent article of the present invention is partially broken. Fig. 2 is a cross-sectional view schematically showing the I-I line section of Fig. 1. Fig. 3 is a plan view schematically showing the skin-facing surface side of the absorbent body included in the absorbent article shown in Fig. 1. Fig. 4(a) is a schematic cross-sectional view taken along the line II-II in Fig. 3, and Fig. 4(b) is a cross-sectional view schematically taken along the line III-III of Fig. 3. Fig. 5 is a longitudinal cross-sectional view schematically showing the section taken along the line IV-IV in Fig. 3. Fig. 6(a) and Fig. 6(b) are respectively a schematic perspective view of the fiber block used in the present invention. Fig. 7 is an explanatory diagram of the method of manufacturing the fiber block used in the present invention.

4: Absorber

11: Fiber block

11F: Constituent fiber (fiber)

11P: Fiber block enrichment part (fiber block layer)

12F: Absorbent fiber

12P: Absorbent fiber enriched part (absorbent fiber layer)

13: Water-absorbing polymer

40: Absorbent core

41: package chip material

A: Front area

B: The area facing the excretion

C: Rear area

X: portrait

Claims (21)

An absorbent article, which has a longitudinal direction corresponding to the front and rear directions of the user, and a transverse direction orthogonal to the longitudinal direction, and has: an excretion facing area, which is arranged opposite to the user's excretion during use; a front area, It is arranged on the longitudinal front side more than the area facing the excretion part; and the rear area, which is arranged on the longitudinal rear side than the area facing the excretion part; and is provided with an absorber; and The above-mentioned absorbent body contains fiber blocks containing synthetic fibers and water-absorbing fibers; In the absorbent body, the ratio of the content of the fiber block to the total content of the fiber block and the water-absorbent fiber is such that the area facing the excretion portion is larger than the front area and the rear area, and the excretion In the facing area, the skin facing side of the absorbent body is smaller than the non-skin facing side of the absorbent body. The absorbent article according to claim 1, wherein the absorbent body contains 90% by mass or more of all the fiber blocks contained in the absorbent body in the region facing the excretion part. The absorbent article of claim 1, wherein the thickness of the absorbent body is that the front area and the rear area are thinner than the lateral center of the area facing the excretion part. The absorbent article of claim 1, wherein the area of the non-skin facing surface of the absorbent body located in the area facing the excretion part is less than 60% of the area of the non-skin facing surface of the absorbent body. The absorbent article of claim 1, wherein the absorbent body contains a water-absorbent polymer at least in the region facing the excretion part, and the content of the water-absorbent polymer in the absorbent body is that the skin facing side There are many non-skin facing sides. The absorbent article according to claim 1, wherein the absorbent body includes an absorbent core containing the fiber block and the water-absorbent fiber, and an outer surface of the absorbent core covering the cored material. The absorbent article according to claim 1, wherein the absorbent body has a protruding part that protrudes toward the skin side of the user from the peripheral part in the region facing the excretion part. The absorbent article according to claim 1, wherein in the absorbent body, a plurality of the fiber blocks or the fiber block and the water-absorbent fiber are entangled with each other. The absorbent article according to claim 3, wherein in the absorbent body, the ratio of the thickness of the front region or the rear region to the thickness of the lateral center of the region facing the excretion part is lowered before the former<the latter, and the former/ In the latter, it is 0.1 or more and 0.9 or less. The absorbent article of claim 1, wherein the ratio of the content of the fiber mass on the non-skin facing surface side of the excretion portion of the absorbent body to the total content of the fiber mass and the absorbent fiber , Based on the premise that it is higher than other parts of the absorbent body, it is 50% by mass or more. The absorbent article of claim 1, wherein the ratio of the content of the fiber mass on the skin opposite surface side of the excretion portion of the absorbent body to the total content of the fiber mass and the water-absorbent fiber, It is assumed that it is lower than the non-skin facing surface side of the excretory portion facing area of the absorbent body, and is 50% by mass or less. The absorbent article according to claim 1, wherein between the non-skin facing surface side of the excretory portion facing area of the absorbent body and the skin facing surface side of the excretory portion facing area of the absorbent body, the fiber The difference in the ratio of the content of the block to the total content of the fiber block and the above-mentioned water-absorbent fibers is 50% by mass or more when the former is subtracted from the latter. Such as the absorbent article of claim 1, wherein the fiber block has two opposing basic planes, and a skeleton plane connecting the two basic planes. The absorbent article of claim 13, wherein in the fiber block, the total area of the two basic planes is greater than the total area of the skeleton plane. Such as the absorbent article of claim 13, wherein the area of the above-mentioned basic surface is 1 mm ² or more and 100 mm ² or less. The absorbent article according to claim 1, wherein the synthetic fiber contained in the fiber block has lower water absorption than the water-absorbent fiber. The absorbent article according to claim 16, wherein the content of the synthetic fiber contained in the fiber block is 90% by mass or more relative to the total mass of the fiber block. The absorbent article of claim 16, wherein the moisture content of the synthetic fiber contained in the fiber block is less than 6%. The absorbent article of claim 1, wherein the moisture content of the above-mentioned absorbent fiber is 6% or more. The absorbent article of claim 1, wherein the contact angle between the fiber block and water is less than 90 degrees. The absorbent article of claim 1, wherein the absorbent article is a menstrual sanitary napkin.

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