JP2009022328A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin absorbent article with high liquid absorptivity, which reduces stuffiness. <P>SOLUTION: An absorbent 4 is provided with a fiber assembly 11 and an adjacent member 13b adjacent to the surface 11b on the non-skin abutting surface side of the fiber assembly 11. The fiber assembly 11 is configured by including one or more of fibers 14 selected from a group comprising synthetic fibers, regenerated cellulose fibers and semisynthetic cellulose fibers and many granular water-absorptive polymers 12. Many granular water-absorptive polymers 12 are unevenly distributed on the non-skin abutting surface side of the fiber assembly 11 before the fiber assembly 11 absorbs liquid, and after the fiber assembly 11 absorbs the liquid, at least part of them is detached from the fiber assembly 11 and interposed between the fiber assembly 11 and the adjacent member 13b to form a water-absorptive polymer layer 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an absorbent article including an absorbent body that includes a water-absorbing polymer.

  Conventionally, absorbent bodies of absorbent articles such as diapers and sanitary products have been composed of a water-absorbing polymer and fluffy wood pulp. From the viewpoint of improving portability and wearing comfort, Development of thin absorbers in which water-absorbing polymers are supported is being carried out. Furthermore, in order to increase the absorption efficiency of the water-absorbing polymer or to provide functionality, it is also known that the water-absorbing polymer is unevenly distributed or the absorber is formed into a multilayer structure.

For example, a thin absorbent body that includes a water-absorbing polymer in a hydrophilic fiber or the like, and a structure in which the water-absorbing polymer is not disposed on the skin contact surface side is known (see Patent Document 1). In order to prevent the water-absorbing polymer from falling off due to dynamic action, the water-absorbing polymer is arranged.
Also known is a multi-functional sheet-like absorbent body having a multilayer structure in which water-absorbing polymers are unevenly distributed in the absorbent layer for functional differentiation of absorption, diffusion and acquisition (see Patent Document 2). ).
Furthermore, in order to improve the performance of liquid retention, improve the absorption efficiency of the water-absorbing polymer, and improve the liquid capture, distribution, and storage properties, an absorber having a laminated structure is also known (Patent Literature). 3).

JP-A-8-246395 JP 2000-201975 A JP 2005-515020 A

  In the techniques described in Patent Documents 1 to 3, since the water-absorbing polymer is dispersed and arranged inside the absorber, water vapor transpiration from the absorber is likely to occur, and the skin is easily swelled. And it was insufficient.

  Accordingly, an object of the present invention is to provide an absorbent article that is thin, has high liquid absorbency, and can reduce stuffiness.

  The present invention provides an absorbent article including a top sheet, a back sheet, and an absorbent body, wherein the absorbent body includes a fiber assembly and an adjacent member adjacent to a surface on the non-skin contact surface side of the fiber assembly. The fiber assembly includes one or more fibers selected from the group consisting of synthetic fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers, and a large number of particulate water-absorbing polymers. The particulate water-absorbing polymer is unevenly distributed on the non-skin contact surface side of the fiber assembly before the fiber assembly absorbs liquid, and at least after the fiber assembly absorbs liquid, By providing an absorbent article, a part of which is detached from the fiber assembly and interposed between the fiber assembly and the adjacent member, the problem is solved. .

According to the absorbent article of the present invention, it is possible to achieve both thinness and absorbability before wearing and liquid absorption, and reduce stuffiness. The absorbent article having such characteristics can realize excellent portability and a feeling of wearing.
In particular, in the present invention, since one or more types selected from the group consisting of synthetic fibers, regenerated cellulose fibers and semi-synthetic cellulose fibers are used as the constituent fibers of the fiber assembly, the other constituent fibers such as, for example, A large amount of water-absorbing polymer can be retained with a smaller amount of fiber than when wood pulp that is usually used is used. This makes it possible to reduce the thickness of the absorber, and the fiber itself is difficult to retain water even after liquid absorption. Because it is difficult to loosen, the stuffiness can be reduced.
Further, the water-absorbing polymer contained in the fiber assembly is unevenly distributed on the non-skin contact surface side before the fiber assembly absorbs bodily fluids such as urine and menstrual blood. An adjacent member (for example, a covering sheet that covers the absorbent body) that is partly detached from the fiber assembly and disposed adjacent to the surface of the fiber assembly and the non-skin contact surface side of the fiber assembly. Since the water-absorbing polymer interposed between the two forms a diffusion layer, it is possible to achieve both absorbency and prevention of stuffiness.

Hereinafter, the absorptive article of the present invention is explained based on the preferred embodiment.
As shown in FIG. 1, the diaper 1 as 1st Embodiment of the absorbent article of this invention concerns on a disposable diaper. The diaper 1 includes a top sheet 2, a back sheet 3, and an absorber 4 interposed between both sheets 2, 3, and is formed substantially vertically long, from one end to the other end in the longitudinal direction of the diaper. On the other hand, the back side A arranged on the back side of the wearer when worn, the excretion part facing part B arranged opposite to the liquid excretion part of the wearer, and the abdominal side part C arranged on the abdomen side of the wearer In order. The diaper 1 is a so-called unfolded diaper in which a pair of fastening tapes 5 and 5 are provided on the left and right edges of the back side A, and the outer surface of the ventral side C (the non-skin of the ventral side C) A landing tape 6 corresponding to the fastening tapes 5 and 5 is provided on the abutting surface side). Solid gathers (not shown) are formed on both sides of the diaper 1 in the longitudinal direction.

  In the diaper 1 of the first embodiment, as shown in FIG. 2, the absorbent body 4 includes a lower part as an adjacent member adjacent to the fiber aggregate 11 and the surface 11 b on the non-skin contact surface side of the fiber aggregate 11. And a covering sheet 13b. The fiber assembly 11 includes a large number of particulate water-absorbing polymers 12 and fibers 14. The lower covering sheet 13b is in contact with the entire surface 11b of the fiber assembly 11 on the non-skin contact surface side.

  The fiber assembly 11 is covered with a covering sheet 13 composed of the lower covering sheet 13b and the upper covering sheet 13a. The covering sheet 13 is a liquid permeable sheet. The upper cover sheet 13 a has the same dimensions as the lengths in the longitudinal direction and the width direction of the absorbent body 4, and is disposed to face the surface 11 a on the skin contact surface side of the fiber assembly 11. The lower covering sheet 13b is wider than the upper covering sheet 13a, is arranged to face the surface 11b on the non-skin contact surface side of the fiber assembly 11, and has portions extending from both side edges of the fiber assembly 11. The upper surface of the fiber assembly 11 is wound on the upper covering sheet 13a that covers the surface 11a on the skin contact surface side. The upper covering sheet 13a and the surface 11a on the skin contact surface side of the fiber assembly 11 are joined by a joining means such as a hot melt adhesive. The absorber 4 is substantially vertically long and has a vertically long rectangular shape (rectangular shape) as a whole.

  The water absorbent polymer 12 is unevenly distributed on the non-skin contact surface side of the fiber assembly 11 as shown in FIG. 2 before the fiber assembly 11 absorbs body fluid such as urine and menstrual blood. At this time, the water-absorbing polymer 12 is held in the fiber gaps of the fibers 14 constituting the fiber assembly 11. Here, “is unevenly distributed on the non-skin contact surface side of the fiber assembly” means that 50% by weight or more, preferably 70% by weight or more of the water-absorbing polymer contained in the fiber assembly is the fiber. Non-skin contact surface side half in the thickness direction of the aggregate (a distance from the surface 11b on the non-skin contact surface side of the fiber assembly 11 corresponding to 50% of the total thickness of the fiber assembly 11 in the thickness direction) Existing in the lower layer region).

Moreover, after the fiber assembly 11 has absorbed the body fluid, the water-absorbing polymer 12 has a large number of water-absorbing polymers 12 detached from the fiber assembly 11 as shown in FIG. It is interposed between the assembly 11 and the lower covering sheet 13b (adjacent member). Thereby, at least a part of the contact portion between the non-skin contact surface side surface 11b of the fiber assembly 11 and the lower covering sheet 13b is separated by the water-absorbing polymer 12 detached from the fiber assembly 11. The
That is, when the fiber assembly 11 absorbs body fluids such as urine and menstrual blood, the fibers 14 constituting the fiber assembly 11 are stretched following the liquid absorption swelling of the water absorbent polymer 12, and the water absorbent polymer 12. Jumps to the outside on the non-skin contact surface side of the fiber assembly 11 when the diameter swells beyond the inter-fiber distance of the fibers 14, and between the fiber assembly 11 and the lower covering sheet 13b (adjacent member). Thus, the water-absorbing polymer layer 15 composed of the detached water-absorbing polymer is formed. By this water-absorbing polymer layer 15, at least a part between the surface 11b on the non-skin contact surface side of the fiber assembly 11 and the covering sheet 13b that have been in contact before liquid absorption is separated.

In the present specification, “liquid absorption” means absorption / retention of 0.1 g or more of liquid substance per 1 cm ² . Examples of the liquid substance include body fluids such as urine, menstrual blood, and vaginal discharge, but are not limited to this range.

  As described above, the water-absorbing polymer 12 is unevenly distributed on the non-skin contact surface side of the fiber assembly 11 before the fiber assembly 11 absorbs liquid. The surface 11b on the non-skin contact surface side of the assembly 11 can easily come out of the fiber assembly 11, and the skin contact surface side half in the thickness direction of the fiber assembly 11 (skin contact of the fiber assembly 11) The water-absorbing polymer 12 is hardly contained in the upper layer region) from the surface-side surface 11a to a distance of a distance corresponding to 50% of the total thickness of the fiber assembly 11 in the thickness direction. In this way, the fiber assembly 11 after the liquid absorption in which the content of the water-absorbing polymer 12 is reduced, the liquid aggregation from the water-absorbing polymer layer 15 made of the water-absorbing polymer 12 held in liquid, and water vapor transpiration are suppressed. It comes to play a role, and this can prevent stuffiness.

  From the viewpoint of improving liquid diffusibility and preventing liquid return and water vapor transpiration, the amount of the water-absorbing polymer desorbed from the fiber assembly 11 in the liquid-absorbed portion after liquid absorption is reduced in the fiber assembly 11 before liquid absorption. Preferably it is 50 to 85 weight% of the water-absorbing polymer 12 contained, More preferably, it is 55 to 85 weight%, More preferably, it is 60 to 80 weight%. Usually, substantially all of the water-absorbing polymer 12 detached from the fiber assembly 11 becomes the water-absorbing polymer layer 15 formed between the fiber assembly 11 and the lower covering sheet 13b (adjacent member). Therefore, the amount of desorbed water-absorbing polymer 12 from the fiber assembly 11 after liquid absorption is in the above range, and the amount of water-absorbing polymer 12 forming the water-absorbing polymer layer 15 is also in the above range. Become.

The thickness of the water-absorbing polymer layer 15 is preferably 0.3 to 2.0 mm, more preferably 0.5 to 1.5 mm, from the viewpoint of the balance between the effects described above and the thinning of the absorber.
The area of the water-absorbing polymer layer 15 (the area in the horizontal plane, the area in the plan view) is preferably 35 to 80% with respect to the area in the plane view of the surface 11b on the non-skin contact surface side of the fiber assembly 11. Preferably it is 40 to 75%.

  The formation of the water-absorbing polymer layer 15 made of the water-absorbing polymer 12 can be confirmed from the fact that it can be separated from the water-absorbing polymer layer 15 when the fiber assembly 11 is peeled off from the absorbent body 4. The amount of the water-absorbing polymer 12 forming the water-absorbing polymer layer 15 protrudes from the surface 11b on the non-skin contact surface side of the fiber assembly 11 when the fiber assembly 11 is peeled off from the absorbent body 4. The water-absorbing polymer 12 remaining on the skin contact surface side of the adjacent member (in the first embodiment, the lower covering sheet 13b) (forming the water-absorbing polymer layer 15). The weight after taking out and drying can be confirmed.

In order to realize the distribution variation of the water-absorbing polymer 12 before and after the liquid absorption, the water-absorbing polymer 12 is unevenly distributed on the non-skin contact surface side of the fiber assembly 11 before the liquid absorption. 50% by weight or more (preferably 70% by weight or more) of the total amount of the water-absorbing polymer 12 contained in the fiber assembly 11 is present on the non-skin contact surface side half in the thickness direction of the fiber assembly 11. is required. In the fiber aggregate in which the water-absorbing polymer is not unevenly distributed, the distribution variation of the water-absorbing polymer before and after the liquid absorption described above does not occur. For example, when 1) the water-absorbing polymer is uniformly distributed throughout the fiber assembly, or 2) the water-absorbing polymer is unevenly distributed on the skin contact surface side of the fiber assembly, the fiber assembly after the liquid absorption The amount of the water-absorbing polymer desorbed from the body is insufficient, and the distribution variation of the water-absorbing polymer hardly occurs.
Further, the interfiber distance of the fibers 14 constituting the fiber assembly 11, the fiber diameter, the average particle diameter of the water absorbent polymer 12, the manufacturing method of the fiber aggregate 11, etc. It is also important to adjust these appropriately because they have a major impact.
The structure of the fiber assembly 11 to be described below can cause fluctuations in the distribution of the water-absorbing polymer before and after the liquid absorption described above.

As the fibers 14 constituting the fiber assembly 11, one or more kinds of fibers selected from the group consisting of synthetic fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers are used. Since these fibers can fix a large amount of water-absorbing polymer with a small amount of fiber compared to wood pulp conventionally used in this type of absorbent body, the absorbent body can be made thin, and the fiber after absorption Since it is difficult to hold the water itself, stuffiness can be reduced.
Examples of the synthetic fiber include hydrophilic synthetic fibers such as polyvinyl alcohol and polyacrylonitrile; hydrophobic synthetic fibers such as polyethylene, polypropylene, and polyester. Examples of the regenerated cellulose fiber include rayon and cupra. Examples of the semi-synthetic cellulose fiber include acetate. Synthetic fibers may be used alone or in combination. When used in combination, a core-sheath structure (concentric or eccentric), a side-by-side type, a split fiber, or the like can be used.

  In order to improve the liquid absorbability, the surface of the fiber 14 is preferably hydrophilic. Examples of the method of imparting hydrophilicity to the fiber surface include a method of hydrophilizing the synthetic fiber surface with a surfactant and a method of kneading a hydrophilic substance into the fiber.

The fibers 14 constituting the fiber assembly 11 are preferably crimped. In particular, the fiber 14 constituting the fiber assembly 11 is preferably a synthetic fiber having crimps because the water-absorbing polymer easily stretches following the liquid absorption swelling. The crimp rate (JIS L0208) of the fiber is preferably 10 to 90%, more preferably 10 to 60%, and still more preferably 10 to 50%.
Since the crimped fiber has stretchability, the water-absorbing polymer is more stably held in the fiber assembly before liquid absorption, and the water-absorbing polymer causes unevenness in the plane direction in the fiber assembly. , Dropping out of the fiber assembly is suppressed. After the liquid absorption, if the water-absorbing polymer swells more than the inter-fiber distance of the fiber assembly, it tends to come out of the fiber assembly.
In addition, since the crimped fiber has extensibility, after the liquid absorption, the crimp is stretched so that the fiber can follow the liquid absorption swelling of the water-absorbing polymer. The crimp shape may be two-dimensional or three-dimensional.

The crimp rate is defined as a percentage of the difference between the length A when the fiber is stretched and the length B of the original fiber before stretching, and is calculated from the following equation.
Crimp rate = ((A−B) / A) × 100 (%)
The length of the original fiber means a length in which both ends of the fiber are connected with a straight line when the fiber is in a natural state. The natural state means a state in which one end of the fiber is fixed to a horizontal plate and hung downward by its own weight. The length when the fiber is stretched refers to the length at the minimum load when the fiber is stretched until there is no crimp. The number of crimps of the fibers 14 constituting the fiber assembly 11 is preferably 2 to 25, particularly 4 to 20, particularly 10 to 20 per 1 cm.

When a crimped fiber is used as the fiber 14 constituting the fiber assembly 11, the fiber assembly 11 itself has stretchability and extensibility.
The stretchability of the fiber assembly 11 can be evaluated by the load at 100% elongation and the residual strain when contracted after 100% elongation. Regarding the degree of stretchability, it is preferable that the load at 100% elongation is 10 to 400 cN / 25 mm, particularly 15 to 100 cN / 25 mm. Moreover, it is preferable that the fiber assembly 11 has a residual strain of 15% or less when contracted from the 100% stretched state.

The elongation rate of the fiber assembly 11 is defined as a percentage of the difference between the length A when the fiber assembly is stretched and the length B of the original fiber assembly before stretching, with respect to the length A. It is calculated from the formula of
Elongation rate = ((A−B) / A) × 100 (%)
The length of the original fiber assembly means a length in which both ends are connected with a straight line in a natural state of the fiber assembly. The natural state means a state in which one end of the fiber assembly is fixed to a horizontal plate and is hung downward by its own weight. The length when the fiber assembly is stretched refers to the length at the minimum load when the fibers constituting the fiber assembly are stretched until there is no crimp. The stretch rate of the fiber assembly 11 is preferably 5 to 75%, more preferably 5 to 70%, and still more preferably 10 to 65%.

The fiber assembly 11 is preferably a card web, garnet web, or airlaid web having an appropriate inter-fiber distance because the water-absorbing polymer 12 is fixed in the fiber gap. These may be very slightly restrained by mechanical entanglement, frictional force, or the like, or may be a nonwoven fabric in which fibers are bonded by thermal bonding, ultrasonic bonding, or the like.
In particular, the fiber assembly 11 is a non-woven fabric from the viewpoint that the water-absorbing polymer 12 is likely to come out of the fiber assembly 11 after liquid absorption, the strength of the absorbent body 4 is excellent, and the leak-proof property is not lowered or twisted. It is preferable. That is, if the fiber assembly 11 is a non-woven fabric, the interfiber distance of the fiber assembly 11 is difficult to spread, so the water-absorbing polymer 12 tends to come out of the fiber assembly 11 (the non-woven fabric is formed by bonding constituent fibers to each other). Since it is configured, the distance between fibers is difficult to spread, and there is a limit to the length of the distance between fibers that can follow the swelling of the water-absorbing polymer, and when the distance between the fibers exceeds this limit, The water-absorbing polymer can easily come out of the nonwoven fabric.) Further, even if a force such as compression or bending is applied to the absorbent body 4 due to the movement of the wearer, the force is distributed through the fusion point of the nonwoven fabric, so that the absorbent body 4 is not easily broken or biased. It becomes difficult for the water-absorbing polymer 12 to move before liquid absorption, and the leak-proof property is not easily lowered.

  The fiber assembly 11 is formed by including the water-absorbing polymer 12 in a fiber web (a precursor of the fiber assembly 11) that includes the fibers 14 and does not include the water-absorbing polymer 12. The interfiber distance of the fibers constituting the fiber web, that is, the interfiber distance of the fibers constituting the fiber web before including the water absorbent polymer in the fiber web is equal to the average particle diameter of the water absorbent polymer 12 or It is preferably smaller than the average particle size, and more preferably smaller than the average particle size. In particular, the interfiber distance of the fibers 14 constituting the non-skin contact surface side (the non-skin contact surface side half in the thickness direction of the fiber assembly 11) when the fiber web becomes the fiber assembly 11 is the water absorption. It is preferably equal to or smaller than the average particle size of the polymer 12, and more preferably smaller than the average particle size. If the distance between the fibers of the fiber web that is the precursor of the fiber assembly 11 is equal to or smaller than the average particle diameter of the water-absorbing polymer 12, the fiber assembly 11 is absorbed before the fiber assembly 11 absorbs liquid. Since the water-absorbing polymer 12 can be contained and fixed inside, the water-absorbing polymer 12 is less likely to fall off the fiber assembly 11. The difference between the interfiber distances of the fibers constituting the fiber web (precursor of the fiber assembly 11) and the average particle diameter of the water-absorbing polymer 12 is preferably 0 to 300 μm, more preferably 0 to 250 μm.

  In addition, even if the distance between the fibers of the fiber web, which is the precursor of the fiber assembly 11, is equal to or smaller than the average particle diameter of the water-absorbing polymer 12, the production of the fiber assembly 11 (absorber 4) and the above-mentioned The distribution fluctuation of the water-absorbing polymer before and after the liquid absorption according to the present invention is not hindered. That is, even when the size relationship between the inter-fiber distance of the fiber web and the average particle diameter of the water-absorbing polymer 12 is as described above, the water-absorbing polymer 12 is included in the fiber web at the time of manufacturing the absorbent body 4. Since the interfiber distance of the fiber web is wide enough to allow the water-absorbing polymer 12 to penetrate into the fiber gap, the fiber web 11 can be made into the fiber assembly 11 by including the water-absorbing polymer 12. Further, after the fiber assembly 11 absorbs the liquid, the inter-fiber distance of the fiber assembly 11 increases to such an extent that the above-described water-absorbing polymer 12 can be detached from the fiber assembly 11 (the water-absorbing polymer of the water-absorbing polymer). Therefore, the distribution fluctuation of the water-absorbing polymer before and after the liquid absorption according to the present invention is not hindered.

  The fiber assembly 11 can be produced, for example, as follows. After the fiber web that is a precursor of the fiber assembly 11 (fiber web including the fiber 14 and not including the water-absorbing polymer 12) is produced according to a conventional method, the water-absorbing polymer 12 is sprayed from one side of the fiber web. It is produced by compressing the one surface with a rubber roller or the like, or sucking in from the opposite side of the one surface (water-absorbing polymer spraying surface), and so that the water-absorbing polymer 12 is caught in the fiber gaps of the fiber web. be able to. The inter-fiber distance of the fibers constituting the fiber web (the inter-fiber distance of the fibers 14 constituting the fiber web before carrying the water-absorbing polymer 12) is preferably 80 μm to 500 μm, more preferably 90 μm to 400 μm, still more preferably. 130 μm to 300 μm. The average particle diameter of the water absorbent polymer 12 will be described later.

  The inter-fiber distance of the fibers 14 constituting the fiber web or fiber assembly 11 is obtained by an expression based on Wrotnowski's assumption. An expression based on Wrotnowski's assumption is generally used to determine the inter-fiber distance of the fibers constituting the nonwoven fabric. Under Wrotnowski's assumption, the fibers are cylindrical, and the fibers are regularly arranged without crossing. The inter-fiber distance A is obtained by the following formula using the thickness h of the nonwoven fabric, the basis weight e, the fiber diameter d of the fibers constituting the nonwoven fabric, and the fiber density ρ.

  The fiber length of the fibers 14 constituting the fiber assembly 11 is preferably less than 70 mm, more preferably 5 mm or more and less than 70 mm, still more preferably 10 to 64 mm, when measured by the average fiber length measurement method (Method C) of JIS L1015. It is. By making the fiber length 5 mm or more, it becomes longer than the fiber length of the fluffy wood pulp fiber used in the conventional absorber, and even a small amount of fiber can fix more water-absorbing polymer, The absorber can be thinned. Further, when the fiber length is less than 70 mm, good spot absorptivity (capability of absorbing the liquid without spreading in the plane direction) can be obtained.

  The fiber diameter of the fibers 14 constituting the fiber assembly 11 is preferably 0.5 to 15 dtex, more preferably 2 to 10 dtex, from the viewpoint of efficiently supporting the absorbent polymer.

  As a material of the water-absorbing polymer 12, various known polymer materials conventionally used for absorbent bodies such as disposable diapers and sanitary napkins can be used. For example, polyacrylic acid soda, (acrylic acid-vinyl alcohol) Examples include copolymers, crosslinked poly (sodium acrylate), (starch-acrylic acid) graft polymers, (isobutylene-maleic anhydride) copolymers and saponified products thereof, potassium polyacrylate, and cesium polyacrylate. . Two or more of these water-absorbing polymers can be used in combination.

  The water absorbent polymer 12 is in the form of particles. The shape of the particles includes a spherical shape, a lump shape, a grape shape, a powder shape, or a fiber shape, and is preferably a lump shape from the viewpoint of fixability to a fiber assembly and liquid absorption performance. Specifically, a water-absorbing polymer hydrogel polymerized by an aqueous solution polymerization method is cast into a plate shape and pulverized after drying, or by controlling the type of surfactant and stirring force by a reverse phase suspension polymerization method. It is formed by agglomerating regular particles.

  The average particle diameter of the water-absorbing polymer 12 is preferably 150 to 600 μm, more preferably 200 to 500 μm, and still more preferably 300 to 400 μm. The average particle diameter of the water-absorbing polymer can be determined as follows.

(Measuring method of average particle diameter of water-absorbing polymer)
The water-absorbing polymer 50g was sieved using a shaker (AS200 type, manufactured by Lecce). The sieve used was a standard sieve manufactured by Tokyo Screen Co., Ltd. defined by JIS Z 8801, and those having an opening of 850, 600, 500, 355, 300, 250, 150 were used. Shaking conditions were 50 Hz, amplitude 0.5 mm, and 10 minutes. The measurement was performed three times, and the average value was defined as the weight on the sieve. The relative frequency was determined by dividing the weight on each sieve obtained by 50, and a particle size cumulative curve was drawn. The particle diameter corresponding to the central cumulative value (50%) of the cumulative curve was taken as the average particle diameter.

  It is preferable that the water-absorbing polymer 12 is not bonded to the fibers 14 constituting the fiber assembly 11 before the fiber assembly 11 absorbs liquid. In other words, it is preferable that the fiber assembly 11 does not include a binder component for bonding the water absorbent polymer 12 to the fiber 14. Here, the “binder component” is separate from the fiber component and the water-absorbing polymer that are added to bind and fix the fiber component in the absorber and the water-absorbing polymer in this type of conventional absorber. For example, a fused fiber (binder fiber), a hot melt pressure-sensitive adhesive, a synthetic binder and the like can be mentioned. In a state where the water-absorbing polymer 12 is not bonded to the fiber 14 but is contained (supported) in the fiber assembly 11, the fiber 14 is entangled or caught in the water-absorbing polymer 12, or water absorption The adhesive polymer 12 adheres to the fiber 14 by developing its own adhesiveness, but the fiber 14 and the water-absorbing polymer 12 are not chemically bonded. As a result, the degree of freedom of movement of the water-absorbing polymer 12 by the liquid absorption does not decrease, and the surface of the water-absorbing polymer is not covered with the binder component and the like, thereby preventing absorption inhibition. Therefore, the distribution variation of the water-absorbing polymer 12 before and after the liquid absorption described above (formation of the water-absorbing polymer layer 15) occurs more reliably.

The water-absorbing polymer 12 has a physiological water absorption of 30 g / g or more, particularly 30 to 50 g / g by centrifugal dehydration, in terms of the amount of water-absorbing polymer used and the gel feeling after liquid absorption. Is preferable from the viewpoint of preventing the decrease. Measurement of the amount of physiological saline absorbed by centrifugal dehydration of the water-absorbing polymer is performed as follows. That is, 1 g of water-absorbing polymer was swollen with 150 ml of physiological saline for 30 minutes, then placed in a 250 mesh nylon mesh bag, dehydrated with a centrifuge for 10 minutes at 143 G (800 rpm), and the total weight after dehydration was measured. To do. Next, the amount of physiological saline absorbed by centrifugal dehydration (g / g) is calculated according to the following formula.
(Water absorption amount by centrifugal dehydration method) = (Whole weight after dehydration−Nylon mesh bag weight−Dry water absorbent polymer weight−Nylon mesh bag liquid remaining weight) / (Dry water absorbent polymer weight)

As for the fiber assembly 11 comprised including the above-mentioned fiber 14 and the water absorbing polymer 12, the basic weight becomes like this. Preferably it is 10-260 g / m < ² >, More preferably, it is 10-100 g / m < ² >, More preferably, it is 10 ˜30 g / m ² . If the basis weight of the fiber assembly is less than 10 g / m ² , the water-absorbing polymer 12 may not be sufficiently fixed. On the other hand, if the basis weight exceeds 260 g / m ² , the fiber assembly becomes bulky and the thickness is increased. In addition, the density of the fiber assembly is increased too much, and the absorbent body becomes hard, which may impair the wearing feeling.

The basis weight of the fiber assembly 11 can be appropriately adjusted according to the purpose. For example, in order to improve the uptake rate of the liquid, when it is desired to prevent the liquid return, 15 to 100 / m ² basis weight, in particular 20 to 80 g / m ^2, that among other things a 25 to 50 g / m ² preferable. On the other hand, when it is desired to increase the cushioning property of the absorbent body, when it is desired to prevent the absorbent body from twisting, when it is desired to impart compression recovery to the absorbent body, and when it is desired to suppress water vapor transpiration, the basis weight is 25 to 200 g / m. ² , particularly 30 to 150 g / m ² , particularly 40 to 120 g / m ² is preferable.

The total content of the fibers 14 and the water-absorbing polymer 12 in the fiber assembly 11 before liquid absorption is preferably 70 to 100% by weight, more preferably 85 to 100% by weight, based on the total weight of the fiber assembly 11. is there.
The weight ratio of the fiber 14 and the water-absorbing polymer 12 in the fiber assembly 11 before liquid absorption is preferably fiber: water-absorbing polymer = 1: 9 to 5: 5 from the viewpoint of thinning the absorber. : Water-absorbing polymer = 1: 9 to 3: 7 is more preferable.

As described above, the absorbent body 4 according to the first embodiment includes the fiber assembly 11 covered with the covering sheets 13 (upper covering sheet 13a and lower covering sheet 13b). Covering the fiber assembly 11 with the covering sheet 13 in this way is effective for improving the shape stability of the fiber assembly 11 and also for maintaining the supported state of the water absorbent polymer 12 in the fiber assembly 11. It is thought that.
As the covering sheet 13, for example, a fiber material sheet or a perforated film can be used. From the viewpoint of good liquid permeation, the covering sheet 13 is preferably made of a hydrophilic fiber sheet. As the hydrophilic fiber sheet, paper such as tissue paper and various non-woven fabrics can be used. Examples of the non-woven fabric include non-woven fabrics made of hydrophilic fibers such as cotton and rayon, and non-woven fabrics made by subjecting synthetic resin fibers to a hydrophilic treatment. Specific examples include a spunbond nonwoven fabric, a spunlace nonwoven fabric, an airlaid nonwoven fabric, and an air-through nonwoven fabric treated with a surfactant.

The diaper 1 of 1st Embodiment can be used similarly to a normal expansion | deployment type diaper.
According to the diaper 1 of 1st Embodiment, the absorber 4 (fiber assembly 11) has the effect | action which hold | maintains bodily fluids, such as urine and a loose stool.

  In particular, in the diaper 1 of the first embodiment, after the fiber assembly 11 absorbs body fluid such as urine, the water-absorbing polymer 12 that is unevenly distributed on the non-skin contact surface side of the fiber assembly 11 absorbs the absorbent. When the liquid 14 swells and pushes away the fibers 14 and exceeds the inter-fiber distance, the fiber aggregate 11 comes out of the surface 11b of the non-skin contact surface of the fiber aggregate 11 and absorbs water as shown in FIG. A water-absorbing polymer layer 15 made of the polymer 12 is formed. For this reason, gel clogging easily occurs in the water-absorbing polymer layer 15, and the liquid diffuses in the planar direction. In particular, in the case of a thin absorber (thickness is preferably 2.5 mm or less, more preferably 0.3 to 2.0 mm) using a non-woven fabric made of synthetic fibers as the fiber assembly 11, Since the volume is small, the liquid fixing volume can be increased by spreading in the plane direction, and the liquid can be fixed with more water-absorbing polymer, so that the absorption performance is improved. Moreover, since the fiber assembly 11 increases the distance between the water-absorbing polymer layer 15 held by the liquid and the skin, liquid return and water vapor transpiration can be prevented, and stuffiness can be prevented.

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the following embodiment, components different from those of the first embodiment described above will be mainly described, and the same components will be denoted by the same reference numerals and description thereof will be omitted. The description of the first embodiment is appropriately applied to components that are not particularly described.

  In the diaper 1 of 2nd Embodiment, the absorber 4 has the hydrophilic fiber assembly 16 adjacent to the surface 11b by the side of the non-skin contact surface of the fiber assembly 11. FIG. That is, in the second embodiment, the hydrophilic fiber aggregate is the adjacent member. The hydrophilic fiber assembly 16 is particularly effective in improving the absorption performance of the absorbent body 4 and improving the shape retention of the fiber assembly 11.

  The laminate of the fiber assembly 11 and the hydrophilic fiber assembly 16 has a surface on the skin contact surface side (surface on the skin contact surface side of the fiber assembly) and a surface on the non-skin contact surface side (hydrophilicity). The surface of the fiber assembly 16 on the non-skin contact surface side) is covered with the covering sheet 13. The absorber 4 is substantially vertically long. The hydrophilic fiber assembly 16 is substantially vertically long, and has an hourglass shape in which the central portion in the longitudinal direction is constricted as a whole. The fiber assembly 11 has a vertically long rectangular shape (rectangular shape). In the form of FIG. 4, the hydrophilic fiber assembly 16 and the fiber assembly 11 have the same length in the longitudinal direction, but are different in length in the width direction. That is, the length in the width direction of the fiber assembly 11 is larger than the width of the narrow portion of the hydrophilic fiber assembly 16 (minimum width in the constricted portion at the center in the longitudinal direction), and the hydrophilic fiber assembly 16 It is smaller than the width (maximum width) of the wide portion.

  The hydrophilic fiber assembly 16 includes the hydrophilic fiber 17 as an essential component. Examples of the hydrophilic fiber 17 include wood pulp such as softwood kraft pulp and hardwood kraft pulp, natural cellulose fiber such as cotton pulp and straw pulp, regenerated cellulose fiber such as rayon and cupra, semi-synthetic cellulose fiber such as acetate, polyvinyl alcohol, and the like. In addition, hydrophilic synthetic fibers such as polyacrylonitrile, and synthetic fibers such as polyethylene, polypropylene, polyester, and the like are coated with a surfactant to impart hydrophilicity. Synthetic fibers may be used alone or in combination. When used in combination, a core-sheath structure (concentric or eccentric), a side-by-side type, a split fiber, or the like can be used. These fibers may be used alone or in combination of two or more. In particular, wood pulp is preferable as the hydrophilic fiber 17 from the viewpoint of improving liquid retention.

  Even if the hydrophilic fiber assembly 16 is a form in which the hydrophilic fibers 17 that are constituent fibers are very slightly restrained by mechanical entanglement, frictional force, or the like, the fibers are bonded together by thermal bonding, ultrasonic bonding, or the like. It may be in the form of a bonded nonwoven fabric or paper. The hydrophilic fiber assembly 16 may be a single layer or a multilayer.

The hydrophilic fiber assembly 16 has a basis weight of 15 to 260 g / m ² , particularly 20 to 200 g / m from the viewpoint of being able to absorb and retain body fluids such as urine and soft stool that have passed through the fiber assembly 11. ² and particularly preferably 25 to 170 g / m ² .
The thickness of the hydrophilic fiber assembly 16 is preferably 1.0 to 2.5 mm, and more preferably 1.5 to 2.0 mm, from the viewpoint of realizing a thin diaper.

In the second embodiment, the hydrophilic fiber assembly 16 includes the water-absorbing polymer 12 in addition to the hydrophilic fiber 17 for the purpose of further improving the absorption performance of the absorber. The distribution amount of the water-absorbing polymer 12 in the hydrophilic fiber assembly 16 is preferably 15 to 260 g / m ² , particularly 20 to 200 g / m ² , and particularly preferably 25 to 170 g / m ² .

  When the hydrophilic fiber assembly 16 includes the water-absorbing polymer 12, the weight ratio of the hydrophilic fiber 17 to the water-absorbing polymer 12 in the hydrophilic fiber assembly 16 sufficiently retains urine, loose stool, menstrual blood, and the like. From the viewpoint of enabling fixation, hydrophilic fiber: water-absorbing polymer = 7: 3 to 3: 7 is preferable, and hydrophilic fiber: water-absorbing polymer = 6: 4 to 3: 7 is more preferable.

  It is preferable that the hydrophilic fiber assembly 16 does not include a binder component for joining the water-absorbing polymer 12 to the fibers (hydrophilic fibers 17) constituting the hydrophilic fiber assembly 16. That is, the water absorbent polymer 12 is preferably not bonded to the hydrophilic fiber 17. This point is the same as the fiber assembly 11 described above. With such a configuration, the degree of freedom of movement of the water-absorbing polymer is reduced, or the surface of the water-absorbing polymer is covered with a binder component or the like, thereby inhibiting absorption. It can be prevented from waking up.

In the diaper 1 of the second embodiment, when bodily fluids such as urine and menstrual blood are excreted toward the surface of the absorbent body 4 on the skin contact surface side, first, in the fiber assembly 11, the water-absorbing polymer described above. Twelve distribution variations occur. That is, a part of the large number of water-absorbing polymers 12 that are unevenly distributed on the non-skin contact surface side of the fiber assembly 11 absorbs and swells and pushes out the fibers 14, and when the distance between the fibers exceeds the distance between the fibers, It detaches | leaves outward from the surface 11b by the side of a non-skin contact surface, and is interposed between the fiber assembly 11 and the hydrophilic fiber assembly 16 (adjacent member). As a result, a water absorbent polymer layer 15 composed of the detached water absorbent polymer 12 is formed between the fiber aggregate 11 and the hydrophilic fiber aggregate 16 (see FIG. 6). Since the water-absorbing polymer layer 15 diffuses body fluid, a wide range of the absorbent body 4 can be effectively utilized.
Further, the fiber aggregate 11 from which the water-absorbing polymer 12 has been detached has a lower content of the water-absorbing polymer 12 than before the liquid absorption, and in particular, the skin contact in the thickness direction of the fiber aggregate 11. Most of the contact side half (the upper layer region extending from the surface 11a on the skin contact surface side of the fiber assembly 11 to a portion spaced by a distance corresponding to 50% of the total thickness of the fiber assembly 11 in the thickness direction) The water-absorbing polymer 12 is not included. As described above, the fiber assembly 11 containing almost no water-absorbing polymer 12 plays a role of separating the distance between the water-absorbing water-absorbing polymer layer 15 and the skin, thereby suppressing liquid return and water vapor transpiration from the absorber. This prevents stuffiness.

Furthermore, in the diaper 1 of the second embodiment, the hydrophilic fiber assembly 16 absorbs a larger amount of liquid because the constituent fibers 17 are hydrophilic and the liquid easily penetrates and the liquid holding ability is high. I can do it. Further, by laminating the hydrophilic fiber assembly 16 on the non-skin contact surface side of the fiber assembly 11, the distance between the hydrophilic fiber assembly 16 that has been liquid-retained after liquid absorption and the skin can be reduced by the fiber assembly 11. Since they can be separated from each other, stuffiness due to liquid return and water vapor transpiration can be suppressed.
Since the disposable diaper of 2nd Embodiment has the absorber 4 comprised as mentioned above, thickness is thin, liquid absorptivity is favorable, and it can reduce stuffiness.

  Next, the preferable manufacturing method of the absorber 4 (absorber 4 shown in FIG. 4) used for the diaper of 2nd Embodiment is demonstrated, referring FIG. The apparatus 20 shown in FIG. 7 is an absorbent body manufacturing apparatus capable of continuously producing the absorbent body 4 shown in FIG. 4 at a high speed.

  When the manufacturing apparatus 20 is operated, a belt-like sheet 13a ′, which is a precursor of the upper covering sheet 13a, is continuously fed out and conveyed by a conveyance mechanism (not shown). Then, the adhesive application device 21 applies an adhesive such as a hot melt adhesive in a predetermined application pattern such as a spiral shape to a predetermined location including the center in the width direction of the sheet 13a ′.

  Next, a nonwoven fabric 11 ′ (nonwoven fabric not containing a water-absorbing polymer), which is a precursor of the fiber assembly 11 separately manufactured according to a conventional method, is continuously placed in the center in the width direction of the continuously conveyed sheet 13a ′. Placed. The nonwoven fabric 11 ′ is an air-through nonwoven fabric, and is placed so that the net surface (the surface on the net side when the nonwoven fabric is manufactured) faces the sheet 13a ′. The nonwoven fabric 11 ′ has a rectangular shape, is formed narrower than the sheet 13a ′, and is bonded and fixed onto the sheet 13a ′ with an adhesive.

  Next, the water-absorbing polymer 12 is uniformly sprayed on the nonwoven fabric 11 ′ by the polymer spraying device 22. The dispersed water-absorbing polymer penetrates into the nonwoven fabric 11 ′ from the air surface (surface opposite to the net side during the production of the nonwoven fabric) of the nonwoven fabric 11 ′ and is supported on the nonwoven fabric 11 ′. As described above, it is preferable to spray the water-absorbing polymer from the air surface side of the nonwoven fabric because the water-absorbing polymer 12 is easily carried on the fiber assembly 11 and easily detached from the fiber assembly 11 after liquid absorption.

  Next, a mixed fiber 16 ′ of hydrophilic fibers and a water-absorbing polymer, which is a precursor of a separately manufactured hydrophilic fiber assembly 16, is overlapped and laminated on the nonwoven fabric 11 ′ being conveyed. . The mixed fiber body 16 'has an hourglass-like shape. The long side of the mixed product fiber 16 'has the same length as the longitudinal direction of the nonwoven fabric 11', and the short side of the mixed product fiber 16 'is the short width of the wide portion (maximum width) of the nonwoven fabric 11'. It is longer than the side and the width of the narrow portion (the minimum width in the constricted portion at the central portion in the longitudinal direction) is shorter than the short side of the nonwoven fabric 11 ′. The mixed fiber body 16 ′ is laminated on the nonwoven fabric 11 ′ so as to face the air surface of the nonwoven fabric 11 ′. In this way, the laminated body 8 formed by laminating the mixed fiber 16 '(precursor of the hydrophilic fiber assembly 16) on the nonwoven fabric 11' (precursor of the fiber assembly 11) is formed.

  Next, a belt-like sheet 13b ′, which is a precursor of the lower covering sheet 13b, is continuously fed out and conveyed by a conveyance mechanism (not shown), and is laminated on the mixed fiber 16 ′ in the laminated body 8 being conveyed. Is done. Before the sheet 13 b ′ is overlaid on the mixed product fiber 16 ′, the adhesive application device 23 applies hot-melt adhesive to a predetermined portion including the central portion in the width direction of the surface facing the mixed product fiber 16 ′. An adhesive such as an adhesive is applied in a predetermined application pattern such as a spiral shape, and the sheet 13b ′ and the mixed fiber 16 ′ are joined by the adhesive. FIG. 8 shows a cross-section in the width direction of the object to be conveyed (the object to be conveyed at a position indicated by X in FIG. 7) obtained in the above process (a section corresponding to the position indicated by the line II in FIG. 4). ) Is schematically shown.

Next, portions 13b′a and 13b′a extending from both side edges of the laminated body 8 of the sheet 13b ′ are wound down by the folding device 24 to the lower surface of the sheet 13a ′ forming the lowermost surface of the laminated body 8, respectively. It is folded back toward the center in the width direction. In this way, absorber continuous body 4 'is obtained.
The folding device 24 includes a pressing means (a roller and / or a guide plate or the like) (not shown) that presses the sheet 13b ′ in the center in the width direction in a state where tension is applied to the sheet 13b ′, and both side parts 13b of the sheet 13b ′. Guide means (rollers and / or guide plates, etc.) (not shown) for bending 'a, 13b'a toward the center in the width direction of the sheet 13b' are provided.

  Next, the absorbent continuous body 4 ′ is pressurized by the press device 25 from the upper and lower surface sides. The press device 25 is a known pressurizing unit that pressurizes a member to be pressed at a nip portion between a pair of rubber rolls. By this pressurization step, the configuration of the absorber continuum 4 ′ is stabilized. In particular, the laminate 8 of the mixed fiber 16 'and the nonwoven fabric 11', which is a precursor of the hydrophilic fiber assembly 16, is pressed from the upper and lower surface sides by this pressurization step, whereby the mixed product. The water-absorbing polymer 12 contained in each of the fine body 16 ′ and the nonwoven fabric 11 ′ firmly bites into each layer, and as a result, the aforementioned water-absorbing polymer supported state is produced. From the viewpoint of reliably producing the supported state, the pressurizing step is preferably performed at a linear pressure of 100 to 800 N / cm.

  When the absorber continuous body 4 ′ thus pressurized is cut into a predetermined length by the cutting device 26 and turned upside down by the inverting device 27, the intended absorber 4 (the absorber of the second embodiment) is obtained. can get.

The absorbent article of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the shape of the absorber is not particularly limited.
Moreover, although the said embodiment concerns a deployment type disposable diaper, this invention is applicable also to other absorptive articles, for example, a pants-type disposable diaper, an incontinence pad, a sanitary napkin, etc.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these.

[Example 1]
An absorber having the same configuration as that of the absorber 4 shown in FIG. 4 was produced by the following procedure. Open a synthetic fiber with a fiber diameter of 3.3 dtex and a fiber length of 64 mm (core-sheathed composite fiber with a core made of polyethylene terephthalate and a sheath made of polyethylene, and hydrophilic because it is surface-treated with a surfactant). Fibers were heat-sealed by hot air treatment to prepare an air-through nonwoven fabric (a precursor of a fiber assembly) having a basis weight of 26 g / m ² . This air-through nonwoven fabric had a rectangular shape with a longitudinal direction of 360 mm and a width direction of 100 mm, a thickness of 0.5 mm, and the interfiber distance of the nonwoven fabric was 93.2 μm. On the air surface of this air-through non-woven fabric (the surface opposite to the net surface that was in contact with the net during the manufacture of the non-woven fabric), the particulate water-absorbing polymer (made by Sundia polymer) Sunwet IM-930 ”, sodium polyacrylate, average particle size 300 μm) 147 g / m ² was sprayed. The nonwoven fabric carrying the water-absorbing polymer thus obtained was used as the fiber assembly.

100 parts by weight of the spread fluff pulp (hydrophilic fiber) and 100 parts by weight of the water-absorbing polymer are uniformly mixed in the air stream on the air surface (spreading surface of the water-absorbing polymer) of the nonwoven fabric (fiber assembly). The obtained hydrophilic fiber assemblies having a basis weight of 330 g / m ² and a thickness of 1.8 mm were stacked to obtain a laminate. The hydrophilic fiber aggregate had an hourglass shape, and the basis weight of the fluff pulp and the water-absorbing polymer in the hydrophilic fiber aggregate was 165 g / m ² . The upper and lower surfaces of the obtained laminate were wrapped with a tissue paper (coating sheet) having a basis weight of 16 g / m ² on which 5 g / m ² of a hot melt pressure-sensitive adhesive was spray-coated. This was compressed with a rubber roller and turned upside down to obtain an absorber. In this nonwoven fabric (fiber assembly), the water-absorbing polymer is supported without being bonded to the synthetic fiber, and 75% by weight of the water-absorbing polymer contained in the nonwoven fabric is air in the thickness direction of the nonwoven fabric. It exists in the surface side half.
The obtained absorbent body had a basis weight of 545 g / m ² and a thickness of 2.4 mm. The size of the absorbent body is 360 mm in the longitudinal direction (the same for both the fiber assembly and the hydrophilic fiber assembly), and the width direction is 100 mm for the rectangular fiber assembly and wide for the hourglass-shaped hydrophilic fiber assembly. The width of the part (maximum width) was 125 mm, and the width of the narrow part (minimum width in the constricted part at the center in the longitudinal direction) was 70 mm.

  As a surface sheet on one surface side of the absorbent body obtained by the above procedure (the net surface of the non-woven fabric constituting the absorbent body, the surface that eventually becomes the skin contact surface side of the absorbent body) A non-woven fabric subjected to hydrophilization treatment comprising a composite fiber having a core-sheath structure in which the core material is polypropylene and the sheath material is polyethylene was provided. Moreover, the polyethylene film was arranged as a back surface sheet on the surface on the other surface side of the absorbent body (surface that finally becomes the surface on the non-skin contact surface side). Furthermore, a known fastening tape, a landing tape, a three-dimensional gather, etc. were arranged to obtain a baby M size disposable diaper having the form shown in FIG.

[Example 2]
A disposable diaper in the same manner as in Example 1 except that the thickness of the core-sheath type composite fiber constituting the nonwoven fabric (fiber assembly) is 6.7 dtex) (the fiber length is the same as in Example 1). This was used as the sample of Example 2.

[Comparative Example 1]
100 parts by weight of the spread fluff pulp and 100 parts by weight of a water-absorbing polymer are uniformly mixed in an air stream to obtain a mixture having a basis weight of 520 g / m ^2. Equivalent). The shape of this mixture was an hourglass shape similar to that of the hydrophilic fiber aggregate of Example 1. The basis weights of the fluff pulp and the water-absorbing polymer in this mixture were 260 g / m ² , respectively. In this mixture, the water-absorbing polymer is distributed substantially uniformly throughout the mixture. The entire mixture thus obtained was wrapped in a tissue paper (coated sheet) having a basis weight of 16 g / m ² on which 5 g / m ² of a hot melt pressure-sensitive adhesive was spray-coated to obtain an absorbent body. The absorbent has a basis weight of 562 g / m ² and a thickness of 3.7 mm. Also, the width of the wide portion (maximum width) and the width of the narrow portion of the absorber (the maximum at the constricted portion in the central portion in the longitudinal direction). The small width) was the same as the hydrophilic fiber aggregate of Example 1.
A disposable diaper was produced in the same manner as in Example 1 except that this absorber was used, and this was used as a sample of Comparative Example 1. Comparative Example 1 is a sample that does not include the above-described fiber assembly according to the present invention.

[Comparative Example 2]
In Example 1, a disposable diaper was produced in the same manner as in Example 1 except that an unbonded web before the non-woven fabric (heat treatment) was used instead of the air-through nonwoven fabric (a precursor of the fiber assembly). A sample of Comparative Example 2 was obtained. In the web that becomes the fiber assembly, the water-absorbing polymer exists uniformly throughout the thickness of the web before liquid absorption.

[Comparative Example 3]
In Example 1, the fiber diameter of the constituent fiber (synthetic fiber) of the fiber assembly (nonwoven fabric) is 2.4 dtex, and the hydrophilic fiber assembly is the net surface (spreading surface of the water absorbent polymer) of the fiber assembly. A disposable diaper was produced in the same manner as in Example 1 except that the absorbent body was produced by superimposing on the opposite surface), and this was used as a sample of Comparative Example 3. In the fiber assembly in the sample of Comparative Example 3, the water-absorbing polymer is unevenly distributed on the skin contact surface side of the fiber assembly.

  About the diaper obtained by the Example and the comparative example, the detachment | desorption amount from this fiber assembly of the water absorbing polymer contained in the fiber assembly was measured with the following method. The results are shown in Table 1 below.

[Measurement of desorption amount of water-absorbing polymer]
A total of 160 g of physiological saline 40 g was injected four times onto the diaper absorber. Then, cut out 70 mm square near the injection part of the diaper (the part where the diaper is completely wet), peel off the top sheet and the fiber aggregate (or the equivalent) in order, and peel off the fiber aggregate. The water-absorbing polymer that protrudes from the non-skin contact surface side of the body and the water absorption that remains (desorbs) on the skin contact surface side of the adjacent member (hydrophilic fiber aggregate or covering sheet) The dry weight (A) of the water-soluble polymer was determined, and the 100 fraction (A / B) with respect to the total amount (B) of the water-absorbing polymer contained in the fiber assembly before liquid absorption was calculated. %).

[Performance evaluation]
About the diaper obtained by the Example and the comparative example, the thickness of the absorber, the urine mole absorption performance, and the evaporation amount were evaluated by the following methods, respectively. These results are shown in Table 1 below.

<Thickness of absorber>
The absorber was taken out from the diaper and the thickness under pressure at 2.5 g / m ² was measured.

<Urine leakage absorption performance>
A diaper is attached to the baby model, and the amount of injection from the time when the artificial urine is injected at a rate of 40 g / time until leakage from the ventral side is measured. This injection amount is defined as urine moisture absorption performance. The greater the amount injected, the higher the urine moisture absorption performance.

<Evaporation amount>
120 g of physiological saline was poured into the diaper and weighed, and the diaper was placed on a flat plate with the top sheet facing up. This was placed in a thermostatic chamber at room temperature 33 ± 2 ° C. and 50 ± 3% relative humidity (RH), and after 16 hours, the weight of the diaper was measured again. The amount of weight reduction of the diaper at this time was defined as the evaporation amount. The smaller the amount of evaporation, the less difficult it is to wear when wearing a diaper.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows 1st Embodiment of the absorbent article of this invention, and the skin contact surface side (surface sheet side) in the expansion | deployment state is partially broken and shown. It is a schematic cross section which shows the II cross section of FIG. 1, and is the state before liquid absorption. It is a schematic cross section which shows the II cross section of FIG. 1, and is the state after liquid absorption. It is a perspective view of the absorber in 2nd Embodiment of the absorbent article of this invention. (A) is a schematic cross-sectional view showing a cross section taken along line II in FIG. 4, (b) is a schematic cross-sectional view showing a cross section taken along line II-II in FIG. 4, and (a) and (b) are both absorbing. It is the state before liquid. It is a schematic cross section which shows the II-II line cross section of FIG. 4, and is the state after liquid absorption. It is a schematic diagram which shows the example of the apparatus which enforces the manufacturing method of the absorber (absorber of 2nd Embodiment) shown in FIG. It is a schematic diagram of the cross section of the to-be-conveyed object (intermediate product) in the location shown by X of FIG. 7, and is a figure which shows the state before completion of the II sectional view of FIG.

Explanation of symbols

1 Water-absorbing articles (diapers)
2 Surface sheet 3 Back sheet 4 Absorber 5 Fastening tape 6 Landing tape 11 Fiber aggregate 11a Surface 11b on the skin contact surface side of the fiber assembly Surface 12 on the non-skin contact surface side of the fiber aggregate 12 Water-absorbing polymer 13 Coating Sheet 13a Upper covering sheet 13b Lower covering sheet (adjacent member of the first embodiment)
14 Fiber 15 Water-absorbing polymer layer 16 Hydrophilic fiber aggregate (adjacent member of the second embodiment)
17 hydrophilic fiber A dorsal part B excretion part opposing part C ventral part

Claims (6)

In an absorbent article comprising a top sheet, a back sheet and an absorbent body,
The absorbent body has a fiber assembly and an adjacent member adjacent to the non-skin contact surface side of the fiber assembly,
The fiber assembly includes one or more fibers selected from the group consisting of synthetic fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers, and a large number of particulate water-absorbing polymers.
A large number of particulate water-absorbing polymers are unevenly distributed on the non-skin contact surface side of the fiber assembly before the fiber assembly absorbs liquid, and at least after the fiber assembly absorbs liquid, An absorbent article, wherein a part thereof is detached from the fiber assembly and interposed between the fiber assembly and the adjacent member.   The absorbent article according to claim 1, wherein the adjacent member is a hydrophilic fiber assembly.   The absorbent article according to claim 2, wherein the hydrophilic fiber aggregate includes a water-absorbing polymer.   The absorbent article according to any one of claims 1 to 3, wherein the fiber assembly is a nonwoven fabric.   The fiber assembly is formed by including the water-absorbing polymer in a fiber web that includes the fibers and does not include the water-absorbing polymer, and the inter-fiber distance of the fibers constituting the fiber web is The absorbent article in any one of Claims 1-4 smaller than the average particle diameter of a water absorbing polymer.   The absorbent article according to any one of claims 1 to 5, wherein the water-absorbing polymer is not bonded to the fibers constituting the fiber assembly before the fiber assembly absorbs liquid.

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