JP4540629B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads.

In Patent Document 1, a three-dimensional sheet having a large number of convex portions is arranged between the top sheet and the absorber, and a portion corresponding to the three-dimensional sheet in the top sheet is raised toward the wearer's skin side. Absorbent articles are described. The absorptive article given in patent documents 1 is excellent in the property which makes the wearer's skin fit, and the fluid transfer to an absorber smoothly.
On the other hand, Patent Document 2 describes an absorbent article having an absorbent body mainly composed of pulp. The absorbent article described in Patent Document 2 has a WC value (compression energy) of 0.59 cN · cm by a KES compression tester by setting the number ratio of fine pulp fibers in the pulp constituting the absorber to 25% or less. It is said to be about / cm ^2, and it can reduce discomfort and pain when worn.

JP 2004-154249 A JP 2004-49696 A

  However, in the absorbent article described in Patent Document 1, the three-dimensional sheet includes a first fiber layer disposed on the top sheet side and a second fiber layer disposed on the absorber side, and contracts the second fiber layer. Thus, the first fiber layer is raised to form the convex portion of the three-dimensional sheet. At this time, if the first fiber layer and the second fiber layer are entirely bonded, the convex shape formed by the shrinkage becomes discrete (the strain relaxation cannot be controlled), and the cushioning properties and body There will be variations in fit. Therefore, it is considered desirable that the first fiber layer and the second fiber layer are partially bonded with a certain regularity. Therefore, the liquid is not sufficiently transferred between the first fiber layer and the second fiber layer, and the liquid remains in the first fiber layer, that is, on the skin side.

  Moreover, the technique described in Patent Document 1 is a technique for improving fit to the body by utilizing the horizontal elastic contractility of the contracted second fiber layer. Therefore, in order to take advantage of the elastic shrinkage, the adhesion to the absorbent body that does not have stretchability has to be partially, by the liquid residue to the second fiber layer that has shrunk and densified, Smooth liquid transfer to the absorber is not possible. Thus, in the absorbent article described in Patent Document 1, it is difficult to achieve both cushioning properties and absorptivity.

  Moreover, the uneven | corrugated shape of the solid sheet of patent document 1 is formed by heat shrinkage | contraction, and forms a convex part using the length which shrink | contracted and remained. Here, the height of the convex portion when contracted to a length of 1 / n of the original emboss interval is expressed by 1/2 × (1-1 / n) sin θ. Here, n represents the case where the original length has shrunk to 1 / n, and represents the angle formed between the hypotenuse and the base when the obtained convex portion is approximated to an isosceles triangle. This formula indicates that the second fiber layer must be shrunk as much as possible in order to increase the height of the convex part, and even if it is shrunk as much as possible, the convex part having a height that is half the original emboss interval. It means that only part can be obtained. Thus, in order to obtain cushioning properties and fitability to the body, the second fiber layer that is densified in an attempt to increase the height of the convex portion is hard, and the liquid permeability is poor.

  On the other hand, in the absorbent article described in Patent Document 2, since the absorbent body is mainly composed of pulp, hydrogen bonds between pulps must be used in order to develop the shape stability of the absorbent body. It is necessary to compress the absorber. Moreover, since pulp has a fiber length as short as 2 to 3 mm, the packing density of the fibers in the laminate tends to be high, and it is difficult to increase the thickness of the absorber with respect to the amount of fibers used. Therefore, in the test using the KES compression tester, the amount of compression displacement is reduced, and there is a limit in increasing the WC value, which is insufficient as an effect that can reduce discomfort and pain during wearing.

  Accordingly, an object of the present invention is to provide an absorbent article having excellent compression recovery and absorbability.

The present invention is an absorbent article comprising a top sheet, a back sheet, and an absorbent body interposed therebetween, wherein the absorbent body is a continuous convex portion in which an absorbent core and a large number of convex portions are continuous. The continuous convex structure is formed from a fiber assembly, and is provided by being partially joined to the top sheet side and / or the back sheet side of the absorbent core, and the convex part The height from the absorbent core is 10 mm or less, and the absorber has a compression work (WC value) by a KES compression tester in the thickness direction of 0.98 cN · cm / cm ² or more. The object is achieved by providing an absorbent article.

  According to the absorbent article of this invention, it is excellent in compression recovery property and absorptivity. In addition, it has an excellent texture when worn, and there is little shakiness of the superabsorbent polymer.

  Hereinafter, the absorbent article of this invention is demonstrated based on the preferable embodiment. The absorbent article of the present invention is mainly used for absorbing and holding excretory body fluids such as urine and menstrual blood. The absorbent article of the present invention includes disposable diapers, sanitary napkins, incontinence pads, etc., but is not limited thereto, and widely includes articles used for absorbing liquid discharged from the human body. .

The absorbent article of the present invention typically includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent disposed between both sheets. As the top sheet and the back sheet, materials usually used in the technical field can be used without particular limitation. For example, as the surface sheet, various nonwoven fabrics or apertured films that have been subjected to a hydrophilic treatment can be used. As the back sheet, a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used. The back sheet may have water vapor permeability.
The absorbent article may further include various members depending on the specific application. For example, when applying an absorbent article to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the left and right sides of the topsheet.

The absorbent article of the present invention will be described more specifically with reference to the drawings based on the disposable diaper according to the first embodiment.
A disposable diaper 1 as a first embodiment of the absorbent article of the present invention is a so-called tape-type diaper as shown in FIG. 1, and as shown in FIG. The absorbent body 4 and the liquid-impermeable back sheet 3 are laminated in this order. At the peripheral edge of the absorber 4, the top sheet 2 and the back sheet 3 are joined. The top sheet 2 and the back sheet 3 are recessed inward in the width direction at the longitudinal center (this edge is referred to as “concave edge 1E”), and have an hourglass shape as a whole in the unfolded state. .

The top sheet 2 and the back sheet 3 are joined to each other by a known joining means at the longitudinal end of the portion located on the abdominal side and the longitudinal end of the portion located on the back side, A waist flap portion 1C is formed. Further, side flap portions 1D are formed on both side edge portions of the portion located on the ventral side portion and both side edge portions of the portion located on the back side portion.
A waist elastic member G1 is stretched on the waist flap portion 1C, and a leg elastic member G2 is stretched along the concave edge portion 1E. A fastening tape G3 is provided on the side flap portion 1D on the back side.

Next, the absorbent body 4 which is a characteristic part of the absorbent article of the present invention will be described in detail.
The absorber 4 has a substantially vertically long shape along the longitudinal direction of the absorbent article in plan view. The shape of the absorbent body 4 in plan view may be, for example, a shape recessed inward in the width direction at the center in the longitudinal direction along the shape of the concave edge 1E, and the ventral side and / or the back side may be wide. It may be T-shaped or I-shaped extending to the peripheral edge in the direction.
As shown in FIG. 2, the absorbent body 4 includes a liquid-retaining absorbent core 5 and a continuous convex structure 6 in which a large number of convex parts 61 are continuous.

The absorbent core 5 is composed of at least a hydrophilic short fiber or a long fiber web having hydrophilicity and a superabsorbent polymer.
Examples of hydrophilic short fibers include natural pulp such as wood pulp, rayon, and cotton. As one embodiment, the absorptive core 5 is a mixed fiber layer composed of a superabsorbent polymer and pulp.

  In addition to the hydrophilic short fibers, the absorbent core 5 can be used in combination with synthetic pulp made of synthetic resin such as polyethylene or polypropylene. Since natural pulp generally has high liquid absorbency, the liquid absorption capacity and absorption rate of the absorbent can be increased by using natural pulp. On the other hand, since synthetic pulp has the property of melting when heated to a predetermined temperature, it increases the strength of the entire absorbent body by melting the synthetic pulp by heating the laminated fiber layer or the entire absorbent body containing the synthetic pulp. Can do.

  The hydrophilic long fibers constituting the absorbent core 5 are inherently hydrophilic long fibers and are not inherently hydrophilic, but are hydrophilic when subjected to a hydrophilic treatment. Both of the long fibers to which is given are included. Preferred long fibers are inherently hydrophilic long fibers, and nylon, acrylic, acetate, and rayon long fibers are particularly preferable. In particular, acetate, which is a fiber having a moisture content of less than 10%, is particularly preferable because it retains its bulkiness even when wet. Here, the moisture content is a value measured in an environment of 25 ° C. and a relative humidity of 65%.

In this specification, the hydrophilic long fiber web refers to a web having a Klem water absorption measured in the orientation direction of preferably 20 mm or more, more preferably 30 mm or more.
The measurement of Klem water absorption is performed, for example, as follows. The superabsorbent polymer is removed from the portion of the absorbent body 4 containing the superabsorbent polymer, and the crab water absorption is performed using the long fiber web in a state where the crimp rate of the long fiber in the absorbent body 4 is maintained. Measure the degree. For the measurement, ion-exchanged water colored with 0.3% red No. 2 (external addition) is used. The height from the water surface 30 seconds after the setting is taken as the Klem water absorption.

  The Klem water absorption is measured according to JISP8141 (1996) “Test method for water absorption by the Krem method of paper and paperboard”. The measurement direction is only the longitudinal direction of the absorber 1. The width of the test piece is 15 mm. The average value of the measured values of the three test pieces is taken as the Krem water absorption. Depending on the test piece, the Klem water absorption varies in the width direction. In this case, a value obtained by substantially averaging (visually) the width direction is taken as the measurement value.

When the operation of removing the superabsorbent polymer from the absorbent body is performed, the web density ρ1 in the absorbent body may be different from the web density ρ2 after the superabsorbent polymer is removed. Therefore, before removing the superabsorbent polymer from the absorbent body, the density ρ1 of the web in the absorbent body was measured in advance, and the density ρ2 of the web after the superabsorbent polymer was removed was measured in advance. After adjusting the state of the web after the superabsorbent polymer is removed so as to be the same as the density ρ1, the Krem water absorption is measured. In order to adjust the density ρ2 to the density ρ1, for example, the web after the superabsorbent polymer is removed may be compressed, and the Klem water absorption is measured in that state. The density ρ1 was, for example, 0.03 to 0.05 g / cm ³ .

The density ρ1 (g / cm ³ ) of the web in the absorber is calculated from the basis weight (g / cm ² ) of the web and the thickness (cm) of the web. The basis weight of the web is calculated from the weight (g) after removing the superabsorbent polymer from the absorbent body and the area (cm ² ). On the other hand, the thickness of the web is measured by the following method. A wrinkle is extended by applying a load of 24.5 kPa to the absorbent body taken out from the absorbent article in advance for 12 hours. Next, a weight is placed on an acrylic plate having a size of 5 cm × 5 cm on the absorber, and the thickness is measured under a state where a load of 0.245 kPa is applied. Specifically, a cross section of the absorber is cut out with a razor blade, the range of the absorber including the web is observed with a 10-fold stereo microscope, and the thickness of the web in the absorber is measured. The number of measurement points is 5, and the average value is the thickness. If the measured value fluctuates 20% or more, delete the data and add another measured value.

Moreover, it is preferable to use what is crimped as a long fiber. The long fiber has a crimp rate (JIS L0208) of preferably 10 to 90%, more preferably 10 to 60%, and still more preferably 10 to 50%. By forming a web from crimped long fibers, it becomes easy to stably and highly embed a superabsorbent polymer in the web. There is no particular limitation on the means for crimping the long fibers. The crimp may be two-dimensional or three-dimensional. The crimp rate is defined as a percentage of the difference between the length when the long fiber is stretched and the length of the original long fiber to the length when stretched, and is calculated from the following equation.
Crimp rate = (A−B) / A × 100 (%)

  The length of the original long fiber means a length in which both ends of the long fiber are connected with a straight line when the long fiber is in a natural state. The natural state means a state in which one end of the long fiber is fixed to a horizontal plate and hung downward by its own weight. The length when the long fiber is stretched refers to the length at the minimum load when the long fiber is stretched until there is no crimp.

  There is no restriction | limiting in particular in the fiber diameter of a long fiber. In general, satisfactory results are obtained by using long fibers of 1 to 10 dtex, in particular 1.7 to 7.8 dtex. In addition, when it is desired to impart resistance to cushioning or cushioning properties, it is particularly preferable to use 2.1 to 7.2 dtex fibers. In the present invention, the long fiber means a fiber having a fiber length of preferably 70 mm or more, more preferably 80 mm or more, and even more preferably 100 mm or more when the fiber length is measured by the average fiber length measurement method (Method C) of JIS L1015. Say. However, when the total length of the web to be measured is less than 100 mm, preferably 50% or more, more preferably 70% or more, more preferably 80% or more of the fibers in the web extend over the entire length of the web. Sometimes the fibers of the web are long fibers. The long fibers used in the present invention are generally called continuous filaments. A bundle of continuous filaments oriented in one direction is generally called a tow. Therefore, the long fiber in the present invention is a concept including a continuous filament. The web in which long fibers are oriented is a concept including a tow layer of continuous filaments. In addition, a part of the long fiber may be cut, and a fiber having a fiber length lower than the above value (cut fiber) may be mixed in the absorbent body.

A superabsorbent polymer can be embedded and supported in the absorbent core 5. “Superabsorbing the superabsorbent polymer” means that the superabsorbent polymer enters the space formed by the pulp and long fibers constituting the absorbent core 5, and the superabsorbent polymer is absorbed even by the violent movement of the wearer. This refers to the state where the polymer is unlikely to move or fall off. At this time, the pulp and the long fiber are entangled with the superabsorbent polymer, or are caught, or the superabsorbent polymer is attached to the pulp and the long fiber due to its own stickiness.
In this way, the superabsorbent polymer is embedded and supported in a pulp pile layer, a hydrophilic long fiber web, and the like.

  As the superabsorbent polymer, a particulate polymer is generally used, but a fibrous polymer may be used. When the absorbent body is made of a long-fiber web, the basis weight of the particulate superabsorbent polymer is the same amount or more and 10 times or less that of the web by using an indeterminate type, a block type or a bowl type. Can be buried and supported. Further, in the case of a spherical particle aggregation type or a spherical type, it can be embedded and supported with a basis weight of the same amount or more and 5 times or less with respect to the web. For these particle shapes, it is desirable to select the former when it is particularly desired to achieve both high absorption and thinning, and the latter when importance is placed on the texture (reduction of the feeling of shaving of the superabsorbent polymer).

As shown in FIGS. 2 and 3, the absorbent core 5 in the first embodiment includes a piled fiber layer 51 of pulp 52, and the superabsorbent polymer 53 is uniformly embedded and supported in the piled fiber layer 51. .
“The superabsorbent polymer is uniformly embedded and supported” means that the superabsorbent polymer is completely evenly disposed in the thickness direction or the width direction of the absorber, and a part of the absorber. When it is taken out, it means a case where the variation in the amount of the superabsorbent polymer has a distribution within twice the basis weight. Such a variation is caused by rarely supplying a superabsorbent polymer excessively and producing a part with an extremely high spraying amount in manufacturing an absorbent article. That is, the term “uniformly” includes cases where inevitably variations occur, and does not include cases where the superabsorbent polymer is distributed so as to intentionally vary.

  Various changes can be made as the state of dispersion of the superabsorbent polymer in the absorbent body in the planar direction. In addition to the state in which the superabsorbent polymer is uniformly dispersed in the plane direction as described above, a state in which the superabsorbent polymer is dispersed so as to be biased toward the front side of the absorbent body is exemplified. That is, there is a state in which the spreading basis weight is the same in the width direction of the absorber and the spreading basis weight is higher toward the front side of the absorber. The absorber in which the superabsorbent polymer is dispersed so as to be biased toward the front side of the absorber has a high effect of preventing liquid leakage from the front side of the body. Such an absorbent body is particularly useful as an absorbent body of a pants-type disposable diaper.

  In another embodiment, a state in which the superabsorbent polymer is dispersed so as to be biased toward the rear side of the absorber, more specifically, a U-shape opened toward the front side of the absorber. Examples include a state where a superabsorbent polymer is dispersed. The absorber in which the superabsorbent polymer is dispersed so as to be biased toward the rear side of the absorber has a high effect of preventing liquid leakage from the rear side of the body. Such an absorbent body is particularly useful as an absorbent body for disposable diapers for low-age infants and bedridden people.

  As another embodiment, a state in which the superabsorbent polymer is not dispersed in the peripheral region of the absorbent body and the superabsorbent polymer is dispersed in the central region surrounded by the peripheral region can be mentioned. The absorber in such a state can effectively prevent the superabsorbent polymer from falling off the absorber because the superabsorbent polymer is not dispersed in the peripheral region of the absorber.

In addition to or instead of these superabsorbent polymer spraying states, the superabsorbent polymer spraying state can be changed in the width direction of the absorber. For example, the spreading basis weight of the superabsorbent polymer in the center part in the width direction of the absorbent body can be made higher than the spreading basis weight of the superabsorbent polymer in both side parts in the width direction. By doing in this way, the liquid leak from a wearer's leg periphery can be prevented effectively. Such an absorber is suitable as an absorber of a disposable diaper. On the other hand, the spreading basis weight of the superabsorbent polymer at both sides in the width direction of the absorber can be made higher than the spreading basis weight of the superabsorbent polymer at the center portion in the width direction. By doing in this way, the spot absorptivity of an absorber can be improved. Such an absorbent body is suitable as an absorbent body for incontinence pads for light incontinence and sanitary napkins. When changing the dispersion state of the superabsorbent polymer in the width direction of the absorbent body, it is preferable that at least the crotch part of the absorbent body has the above-described structure.
The dispersion state of these superabsorbent polymers can be implemented in combination as appropriate.

  In the first embodiment, the absorbent core 5 is covered with a water-permeable covering sheet 41. Examples of the covering sheet 41 include tissue paper, spunbond nonwoven fabric, spunbond-meltblown-spunbond nonwoven fabric, spunbond-meltblown-meltblown-spunbond nonwoven fabric, needle punch nonwoven fabric, spunlace nonwoven fabric, dry pulp sheet, air-through nonwoven fabric, An airlaid sheet or the like can be used. These non-woven fabrics can be made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate alone or using these composite fibers. Further, natural pulp such as wood pulp, semi-synthetic fibers such as rayon, cotton, and acetate may be mixed.

  In the absorbent article of the present invention, the continuous convex structure 6 is partially bonded to the top sheet 2 side and / or the back sheet 3 side of the absorbent core 5. In the first embodiment, the continuous convex structure 6 is provided only on the surface sheet 2 side of the absorbent core 5.

In the first embodiment, the continuous convex structure 6 is formed of a long fiber assembly (an assembly of a plurality of long fibers). Each long fiber extends substantially in one direction when the absorbent body 4 is viewed in plan (hereinafter, this direction is also referred to as the X direction of the absorbent body 4), and the fiber assembly includes a predetermined number of long fibers. Are formed in a distributed manner in the width.
The long fibers forming the fiber assembly are preferably the same as the long fibers forming the absorbent core 5 described above.

  The fiber assembly has a continuous convex structure 6 in which a large number of convex portions 61 are continuously formed. The long fibers are oriented in the X direction of the absorbent body 4. This X direction is also the machine direction when the absorber 4 is manufactured. It is preferable that the X direction of the absorber 4 is along the longitudinal direction of the disposable diaper (absorbent article) 1 from the viewpoint of improving the touch and leakproofness.

  The orientation of the long fiber is sufficient if the vector connecting the start point and end point of the long fiber is oriented in the plane direction, and part of the long fiber is in the vertical direction due to twisting or entanglement between the start point and the end point. Including those that face (the thickness direction of the absorber). More specifically, the degree of orientation of the long fibers is preferably 1.2 or more, particularly 1.4 or more in terms of the degree of orientation. In this embodiment, the degree of orientation is measured using a Microwave molecular orientation analyzer MOA-2001A manufactured by KANZAKI. The sample size is 100 mm in the longitudinal direction and 50 mm in width, and the average value of three points is the degree of orientation. When the sample size is less than this size, measurement is performed by arranging a plurality of samples so as not to overlap each other.

As shown in FIG. 2A, the continuous convex structure 6 and the absorbent core 5 are intermittent in the X direction of the absorber 4 and the direction orthogonal to the X direction (hereinafter also referred to as the Y direction). As a result, a large number of joints 62 between the continuous convex structure 6 and the absorbent core 5 are formed in a staggered pattern in plan view.
In the first embodiment, the large number of joints 62 in series in the X direction and the Y direction of the absorber 4 are each at an equal pitch, and the shape of each joint 62 is rectangular in plan view.
In another embodiment, the pitch of the joints 62 can be partially changed. By making the pitch fine, the convex portion 61 becomes fine, and the fit is improved with respect to a place where the body curvature is large, for example, a crotch part, a urine drainage part, a laceration part or the like. Moreover, since the flow of a liquid can be suppressed, a leak can be suppressed by arranging to the product longitudinal direction and the width direction edge part. These pitches may be used alone or in combination.

  In the continuous convex structure 6, a portion other than the joint portion 62, specifically, a portion between the joint portions 62 and 62 adjacent to each other in the X direction is separated from the absorbent core 5 and stretched toward the surface sheet 2 side. It protrudes so as to protrude, and the protruding portion forms a convex portion 61 having a substantially inverted U-shaped cross section.

  In the first embodiment, the partial joint between the continuous convex structure 6 and the absorbent core 5 is configured by embedding the continuous convex structure 6 in the absorbent core 5 as shown in FIG. ing. Specifically, the valley in the continuous convex structure 6 is the absorbent core 5 (when the absorbent core 5 is covered with the covering sheet 41 before the continuous convex structure 6 is partially joined. The continuous convex structure 6 of the covering sheet 41 (including the covering sheet 41) is disposed and bonded to an embedded recess 54 which is recessed from a surface (hereinafter referred to as “absorbent core reference surface”) S.

As for the convex part 61 of the continuous convex structure 6, the height h from the absorptive core 5 is 0.5-10 mm, Preferably it is 0.8-5 mm. The height h of the convex portion 61 is the height of the apex from the reference surface S of the absorbent core 5.
The height h of the convex portion 61 is measured by applying a load of 24.5 kPa to the absorbent body 4 in advance for 12 hours so that there is no wrinkle, and then cutting the measurement portion in the thickness direction and leaving it for 5 minutes. To do later. Specifically, a weight is placed on an acrylic plate having a size of 5 cm × 5 cm on the absorber, and the measurement is performed in a state in which a pressure adjusted to 0.245 kPa is placed on the sample. The measurement device used was a KEYENCE LK080 class 2 laser displacement meter. The number of measurement points was an average of 5 points, and when the measurement value fluctuated by 20% or more, the data was deleted and another sample was added.

The distance in plan view between adjacent convex portions 61 in the continuous convex structure 6 is preferably 0.5 to 10 mm, and more preferably 2 to 7 mm in the longitudinal direction of the absorbent article. Moreover, the planar view space | interval of the convex part 61 becomes like this. Preferably it is 1-10 mm in an absorbent article width direction, More preferably, it is 2-7 mm. The planar view interval of the convex portion 61 is measured with the apex as a reference. The number of convex portions per unit area (1 cm ² ) is preferably 1 to 20, particularly 6 to 15.

The continuous convex structure 6 preferably contains a superabsorbent polymer (not shown) in a range smaller than the content of the superabsorbent polymer 53 in the absorbent core 5. In particular, the content of the superabsorbent polymer in the continuous convex structure 6 is preferably 50% or less less than the content of the superabsorbent polymer 53 in the absorbent core 5. The continuous convex structure 6 may not contain any superabsorbent polymer. When the content is defined as described above, the convex portion 61 is not filled with the swollen superabsorbent polymer 53 even when the liquid is absorbed, so that gel blocking does not occur and repeated absorption is performed. Maintains rapid liquid permeability. In addition, when the whole shape can change like the inside of the absorptive core 5, gel blocking can be prevented by using the superabsorbent polymer 53 with high gel strength. However, when the concavo-convex structure is fixed as in the absorbent article of the present invention, even when the superabsorbent polymer 53 having a high gel strength is used, if the superabsorbent polymer 53 is blended at a high concentration, gel blocking is caused. Cause absorption performance to drop.
In addition, there is an advantage that the compression characteristic of the convex portion 61 is dominated by the compression characteristic of the gel (there is a gel feeling) or the liquid is retained on the skin surface so that the dry feeling is not lost.

In view of such an object of the present invention, examples of preferable superabsorbent polymers are as follows.
First, from the viewpoint of reducing the amount of superabsorbent polymer used and preventing the gel feeling after liquid absorption from being reduced, the amount of physiological saline absorbed by centrifugal dehydration is 30 g / g or more, particularly 30 to 50 g. / G is preferable. The water absorption amount of the superabsorbent polymer by centrifugal dehydration is measured as follows. That is, 1 g of superabsorbent 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 at 143 G (800 rpm) for 10 minutes, and the total weight after dehydration was determined. taking measurement. Next, the amount of water absorption (g / g) by centrifugal dehydration is calculated according to the following formula.
Water absorption by centrifugal dehydration method = (Total weight after dehydration-Weight of nylon mesh bag-Weight of superabsorbent polymer at drying-Weight of remaining liquid in nylon mesh bag) / Weight of superabsorbent polymer at drying

Furthermore, it is more preferable to use a superabsorbent polymer having a high liquid passing rate under load. As the superabsorbent polymer, a polymer having a liquid flow rate of 30 to 300 ml / min, preferably 32 to 200 ml / min, more preferably 35 to 100 ml / min is used.
When the value of the liquid flow rate is less than 30 ml / min, the superabsorbent polymers saturated and swollen by the liquid absorption adhere to each other under load, thereby preventing the passage of the liquid, and gel blocking is likely to occur. The larger the value of the liquid flow rate, the better from the viewpoint of preventing the occurrence of gel blocking.

  When the liquid flow rate exceeds 300 ml / min, the fluidity of the liquid in the absorber is too high, especially when a large amount of excreta is excreted at once, or in the case of older infants or adults. As described above, when the excretion rate is fast, when the absorber is further thinned, the liquid is not sufficiently retained, and there is a possibility of leakage. In general, increasing the liquid flow rate increases the degree of crosslinking of the superabsorbent polymer, lowering the absorption capacity per unit weight of the superabsorbent polymer, and a large amount of superabsorbent polymer must be used. I must. From these viewpoints, the upper limit value of the flow rate is determined.

  The flow rate of the superabsorbent polymer is measured under a 2.0 kPa load. This load substantially corresponds to the body pressure applied to the absorbent body while wearing the absorbent article. A specific method for measuring the flow rate is described in paragraph [0005] of Japanese Patent Laid-Open No. 2003-235889, for example. In the present invention, the measurement is performed by changing 0.200 g, which is the weight of the sample used in the measurement method described in this publication, to 0.32 g. Specifically, the flow rate is measured by the following procedure.

[Measurement method of flow rate]
A filtering cylindrical tube provided with a wire mesh (mesh size 150 μm) and a narrow tube (inner diameter 4 mm, length 8 cm) with a cock (inner diameter 2 mm) at the lower end of a vertically standing cylinder (inner diameter 25.4 mm). prepare. With the cock closed, 0.32 g of a measurement sample adjusted to a particle size of 850 to 150 μm is put into the cylindrical tube. Next, 50 ml of 0.9% by weight physiological saline is poured into the cylindrical tube. After standing for 30 minutes from the start of pouring physiological saline, a cylindrical rod (21.2 g) having a wire mesh with an opening of 150 μm and a diameter of 25 mm at the tip was inserted into the filtration cylindrical tube, and the wire mesh and Make the measurement sample touch. After 1 minute, a 77.0 g weight is attached to the cylindrical rod and a load is applied to the measurement sample. After another 1 minute, open the cock. The time (T1) (second) until the liquid level of the physiological saline solution reaches the 20 ml scale line from the 40 ml scale line is measured. Using the measured time T1 (seconds), the liquid passing time is calculated from the following equation. In the formula, T0 is the time measured without putting the measurement sample in the filtering cylindrical tube.
Flow rate (ml / min) = 20 × 60 / (T1-T0)

  A more detailed method for measuring the flow rate is described in paragraphs [0008] and [0009] of JP-A No. 2003-235889. The measuring device is described in FIGS. 1 and 2 of the publication.

  The superabsorbent polymer that can be used in each of the above-described embodiments is not particularly limited as long as it satisfies the above-mentioned characteristics. Specifically, for example, sodium polyacrylate and (acrylic acid-vinyl alcohol) Examples thereof include a polymer, a crosslinked polyacrylic acid soda, a (starch-acrylic acid) graft polymer, a (isobutylene-maleic anhydride) copolymer and a saponified product thereof, potassium polyacrylate, and cesium polyacrylate. In order to satisfy the above-described characteristics, for example, the crosslink density inside and on the surface of the superabsorbent polymer may be adjusted, or a crosslink density gradient may be provided on the particle surface. Alternatively, the superabsorbent polymer particles may be non-spherical amorphous particles. In particular, by adopting a reverse phase suspension polymerization method using an anionic surfactant described in Japanese Patent No. 2721658 relating to the earlier application of the present applicant as a dispersant, it has a desired liquid flow rate. A superabsorbent polymer is obtained. Alternatively, the method described in JP-A-7-18495, column 7 line 28 to column 9 line 6 can be used.

  The inside of the convex part 61 in the continuous convex structure 6 may be filled with a constituent fiber of the fiber aggregate forming the continuous convex structure 6 or another fiber (not shown). As shown, the fibers may not be filled (ie, they may be hollow).

The absorbent body 4 as a whole (that is, the whole of the absorbent core 5 and the continuous convex structure 6 combined) has a compression work (WC value) of 0.98 cN by the KES compression tester in the thickness direction. · It is cm / cm ² or more, preferably 1.47 cN · cm / cm ² or more. This compression modulus was measured using a Kato Tech KES-G5 handy compression tester. That is, a 5 cm × 10 cm test piece was prepared and attached to a test bench. The specimen was compressed between steel plates having a circular plane with an area of 2 cm ² . The compression speed was 20 μm / sec and the maximum compression load was 4.9 kPa. The recovery process was also measured at the same rate. The compression work WC is expressed by the following equation. Tm, T0 and P indicate respectively 4.9kPa (50gf / cm ²⁾ Thickness of time load, a load of 49Pa (0.5gf / cm ²⁾ when the thickness and measuring the time of loading.

  When the compression work amount (WC value) is specified, there is no sense of incongruity due to the uneven structure of the absorber, excellent recovery after pressure release (for example, after removal from the pack), and cushioning properties. An absorbent article can be provided, and it has an advantage that it can be fitted to the body immediately after being taken out, can quickly absorb liquid, and can be made very compact by compression.

  The convex portion 61 is provided on the side of the topsheet 2 in the absorbent core 5 so as to project toward the topsheet 2, and the apex thereof is joined to the topsheet 2. The apex of the convex portion 61 and the surface sheet 2 are joined by, for example, hot melt or heat fusion. When such bonding is performed, the liquid is quickly absorbed from the convex portion, the liquid does not remain on the entire surface sheet, and the pressure is dispersed to reduce the liquid return, so that the skin remains dry. There is an advantage that can be.

  Next, the manufacturing method of the absorber 4 in the disposable diaper 1 of 1st Embodiment is demonstrated. As shown in FIG. 5, first, on the long absorbent core material 5 ′ that is the material of the absorbent core 5, the continuous continuous convex structure that is the material of the continuous convex structure 6. The material 6 ′ is laminated.

Next, the laminated body of the continuous convex structure body material 6 ′ and the absorbent core material 5 ′ is embossed by the embossing roll R1 and the smoothing roll R2 provided with the embossing R11 on the peripheral surface. As shown in FIG. 6, the embossing R11 of the embossing roll R1 has a shape and an arrangement corresponding to the convex portion 61 and the joint portion 62 of the continuous convex portion structure 6. By the embossing by the pair of embossing rolls R1 and smoothing rolls R2, the convex portions 61 are continuously formed in a predetermined arrangement on the continuous convex structure body material 6 ′, and the continuous convex structure 6 is obtained. Here, the upper surface of the absorbent core 5 is recessed to form the embedded recess 54, and the valley portion in the continuous convex structure 6 breaks through the covering sheet 41 and is entangled with the absorbent core 5, thereby forming the joint 62. The And the laminated body of the continuous convex structure 6 and the absorptive core 5 is cut | disconnected by cutter C to predetermined length.

As a result, the trough portion in the continuous convex structure 6 is embedded in the embedded concave portion 54 of the absorbent core 5, and the absorbent body 4 in which the continuous convex structure 6 is partially joined to the absorbent core 5 is obtained.
The absorbent body 4 formed of the laminate of the continuous convex structure 6 and the absorbent core 5 formed in this way is joined to the top sheet 2, the back sheet 3, and the elastic member in the next step (not shown). Arrangement, cutting into a predetermined shape, and the like are performed, and the disposable diaper 1 is obtained.

According to the disposable diaper 1 of 1st Embodiment, the absorber 4 consists of the absorptive core 5 and the continuous convex structure 6, and the compression work of the height h of the convex part 61 and the thickness direction of the absorber 4 is the same. Since it is defined within a predetermined range, it is excellent in compression recovery and absorbability. In addition, it has an excellent texture when worn, and there is little shakiness of the superabsorbent polymer.
Moreover, since the continuous convex structure 6 is embedded in the absorbent core 5 and partially joined, the liquid can be quickly transferred to the absorbent core 5 without using an adhesive.

Next, the variation of the arrangement | sequence form of the continuous convex structure 6 is illustrated concretely. Regarding the points that are not particularly described, since the description of the first embodiment is appropriately applied, the same components are denoted by the same reference numerals and the description thereof is omitted. Also in the absorbent article provided with the continuous convex structure 6 having a different arrangement form, the same effect as in the first embodiment is exhibited.
As shown in FIG. 7, the arrangement form of the continuous convex structure 6 is an arrangement form in which the convex portions 61 adjacent to each other in the width direction and the longitudinal positions of the convex portions 61 are aligned (not shifted). Can do. In such an arrangement, the liquid diffusibility is improved, and liquid return can be reduced. In addition, there is an advantage that a linear flexible shaft can be easily formed on the continuous convex structure 6, and the convex part is not crushed by folding creases even when the absorbent article is folded.

As shown in FIG. 8, the continuous convex structure 6 is biased toward the abdominal side or the back side, with the excretion part when the absorbent article is mounted as the center, in the entire longitudinal direction of the absorbent body 4. Can be provided. With such an arrangement, there is an advantage that the body fit and the absorbent article can be made thin. In the case of a tape-type disposable diaper, the entire product tends to be thick due to a fastening tape or the like when packaging the package, which is particularly beneficial.
As shown in FIG. 9, the continuous convex structure 6 can be provided only on both sides in the width direction when the width direction of the absorber 4 is divided into approximately three equal parts. Such an arrangement has an advantage that the continuous convex structure 6 functions as a leak-proof wall.

  As shown in FIG. 10, the joint portion 62 of the continuous convex structure 6 is not embedded in the absorbent core 5, but the absorbent core 5 (when the absorbent core 5 is covered with the covering sheet 41). Can also be partially bonded to the top sheet 2 side and / or the back sheet 3 side). Such a form of partial joining can be constituted by adhesion, heat fusion, or the like.

As shown in FIG. 11 (a), the continuous convex structure 6 is formed on the absorbent core 5 on the topsheet 2 side and the backsheet 3 side, respectively, with the convex portions 61 on the topsheet 2 on the absorber 4 side. The surface and the back sheet 3 can be provided so as to protrude toward the surface on the absorber 4 side. In such an arrangement, the absorber 4 has a high compression elastic modulus in the thickness direction.
In the absorbent body 4, as shown in FIG. 11 (b), the entire structure in which the continuous convex structure 6 is partially joined to the absorbent core 5 can be covered with a covering sheet 41.

As shown in FIG. 12A, the continuous convex structure 6 can be provided so that the convex portion 61 is convex toward the absorbent core 5 on the surface of the topsheet 2 on the absorber 4 side.
As shown in FIG. 12 (b), the continuous convex structure 6 can also be provided with a convex portion 61 on the surface of the back sheet 3 on the absorbent body 4 side so as to protrude toward the absorbent core 5.
In the form shown in FIG. 12A and FIG. 12B, the apex of the convex portion 61 is in the absorbent core 5 (or the covering sheet 41 when the absorbent core 5 is covered with the covering sheet 41). It is joined to the top sheet 2 side or the back sheet 3 side by adhesion, heat fusion or the like.

  In the absorbent body 4, the absorbent core 5 can be formed narrow, and the continuous convex structure 6 can be provided on both sides of the absorbent core 5. In this case, as shown in FIG. 12C, the convex portion 61 can be provided on the surface of the backsheet 3 on the side of the topsheet 2, or can be provided on the surface of the topsheet 2 on the side of the backsheet 3. (Not shown). In such an arrangement form, the continuous convex structure works as a leak-proof wall to suppress leakage, and since the absorbent body is narrow, there is an advantage that the fitting property at the crotch part is further improved. In this case, it is preferable that the absorbent core 5 is formed so that only the crotch portion is narrow and the abdomen and the back are widened.

  As shown in FIG. 13, a large number of convex portions 61 in the continuous convex structure 6 can be provided on the absorbent core 5 by being inclined in one direction. In the form in which the loop portion of the convex portion 61 is uniformly projected upward, when the pressure caused by the wearing pressure or the movement of the body is applied to the loop portion, each loop portion is independently in various directions. If it is inclined, the touch may be deteriorated due to this, and the absorbability of the liquid may also be deteriorated. However, in such a form inclined in one direction, the inclination direction is determined. Therefore, the texture is good and the flow of the liquid can be suppressed, so that there is an advantage that leakage can be suppressed.

  Openings 21 can be provided in the topsheet 2 at positions corresponding to the joints 62 of the continuous convex structure 6 in plan view. Thus, when the opening 21 is formed in the surface sheet 2, there exists an advantage that the drawing property of the liquid from the surface sheet 2 to the absorptive core 5 improves. In the absorbent article shown in FIG. 14, the convex portion 61 of the continuous convex structure 6 is provided so as to protrude toward the surface sheet 2 on the surface sheet 2 side in the absorbent core 5. Further, the opening 21 is formed so that the topsheet 2 does not go around between the convex portions 61 adjacent to each other.

The disposable diaper which has the opening 21 in the surface sheet 2 as shown in FIG. 14 can be manufactured as follows, for example.
As shown in FIG. 15, first, a long surface sheet material 2 ′ that is a material of the surface sheet 2 is laminated on the long fiber assembly 6 ″ that is a material of the continuous convex structure 6. An adhesive such as a hot melt agent is applied to the fiber assembly 6 ″ side of the surface sheet material 2 ′. Immediately thereafter, the laminated body of the top sheet material 2 ′ and the fiber assembly 6 ″ is subjected to hole embossing by a pair of embossing rolls R3 and R3 provided with embossing having a large number of pins (needles) on the peripheral surface. The embossing of the embossing roll R3 has a shape and an arrangement corresponding to the convex part 61 and the joint part 62 of the continuous convex part structure 6.

  By the embossing by the pair of embossing rolls R3 and R3, the opening 21 is formed at a position corresponding to the joining portion 62 in the surface sheet material 2 ′, and the convex portion 61 is continuously arranged in a predetermined arrangement in the fiber assembly 6 ″. Is formed to obtain a continuous convex structure material 6 ′ having a long shape, and the surface sheet material 2 ′ and the continuous convex structure material 6 ′ are a continuous convex structure in the surface sheet material 2 ′. It joins to the raw material 6 'side surface in the form where the vertex of the convex part 61 is partially adhered by an adhesive.

Next, a laminate of a surface sheet material 2 ′ having an opening 21 and a continuous convex structure material 6 ′ on a long absorbent core material 5 ′ that is a material of the absorbent core 5. Are joined by a pair of smooth rolls R4 and R4. Before being introduced between the pair of smooth rolls R4 and R4, the absorbent core material 5 ′ side of the laminate of the surface sheet material 2 ′ and the continuous convex structure material 6 ′ is bonded with a hot melt agent or the like. The agent is applied. As a result, the valley portion of the continuous convex structure material 6 ′ is partially bonded to the upper surface of the absorbent core material 5 ′ to form the bonded portion 62.
The laminated body of the top sheet material 2 ′, the continuous convex structure material 6 ′, and the absorbent core material 5 ′ formed in this way is bonded to the back sheet 3 in the next step (not shown). Arrangement, cutting into a predetermined shape, and the like are performed, and an absorbent article such as a disposable diaper is obtained.

  In addition, as shown in FIG. 16, the opening 21 can be formed so that the topsheet 2 wraps between the adjacent protrusions 61 and the protrusions 61, and further, at a position corresponding to the opening 21. An opening 63 can be formed in the joint 62 of the continuous convex structure 6, and an opening 42 can be formed in the covering sheet 41. The upper surface of the absorbent core 5 is recessed corresponding to the opening 42, and an embedded recess 54 is formed.

The disposable diaper which has the opening 21, the opening 63, and the opening 42 in the surface sheet 2, the joining part 62, and the coating sheet 41 as shown in FIG. 16 can be manufactured as follows, for example.
As shown in FIG. 17, first, on the long absorbent core material 5 ′ serving as the material of the absorbent core 5, the long fiber assembly 6 ″ serving as the material of the continuous convex structure 6. Then, the laminated body of the fiber assembly 6 ″ and the absorbent core material 5 ′ is cut into a predetermined length by the cutter C, and the continuous convex structure material 6 ′ and the absorbent core 5 are laminated. Let it be the body.

  Next, a long surface sheet material 2 ′ which is a material of the surface sheet 2 is laminated on a laminate of the continuous convex structure material 6 ′ and the absorbent core material 5 ′. An adhesive such as a hot melt agent is applied to the continuous sheet structure material 6 ′ side of the surface sheet material 2 ′. Immediately thereafter, an embossing roll R5 and a smooth roll having an embossment having a large number of pins (needles) on the peripheral surface of a laminate of the surface sheet material 2 ′, the continuous convex structure material 6 ′, and the absorbent core 5 Embossed with R6. The embossing of the embossing roll R5 has a shape and an arrangement corresponding to the convex part 61 and the joint part 62 of the continuous convex part structure 6. By the embossing by the pair of embossing rolls R5 and smoothing rolls R6, the apertures 21 are formed at positions corresponding to the joints 62 in the topsheet 2, and the convex portions are continuously formed in a predetermined arrangement on the continuous convex structure material 6 ′. 61 is formed, and the continuous convex structure 6 is obtained. Moreover, the trough part of the continuous convex structure 6 is entangled with the absorbent core 5, and the joint part 62 is formed. Furthermore, an opening 63 and an opening 42 are formed in the joint portion 62 and the covering sheet 41, respectively. The upper surface of the absorbent core 5 is recessed corresponding to the opening 42, and an embedded recess 54 is formed.

As a result, the valley of the continuous convex structure 6 is embedded in the absorbent core 5, and the continuous convex structure 6 is partially joined to the absorbent core 5.
The laminated body of the top sheet material 2 ′, the continuous convex structure 6 and the absorbent core 5 formed in this way is joined to the back sheet 3, the arrangement of the elastic member, and the predetermined shape in the next step (not shown). The absorbent article such as a disposable diaper is obtained.

The manufacturing method shown in FIG. 17 is easy to form the convex part 61 with which the fiber was filled inside, and is suitable for manufacture of the absorbent article which has such a convex part 61. FIG.
The disposable diaper having the opening 21, the opening 63, and the opening 42 in the top sheet 2, the joining portion 62, and the covering sheet 41, respectively, as shown in FIG. 16, includes not only low-viscosity excrement such as urine. Also, there is an advantage that it is possible to absorb a liquid having a certain degree of viscosity such as loose stool and menstrual blood.

  As shown in FIG. 18, the joint 62 between the continuous convex structure 6 and the absorbent core 5 is composed of a large number of small joints 64 that are discontinuously arranged. A large number of closed regions 65 surrounded by the joint 64 may be formed. The long fibers 66 forming the continuous convex structure 6 in each closed region 65 are substantially all of the small joints at the boundary with the other closed regions 65 located before and after the orientation direction. 64 is fixed.

  Next, the absorber 4 in 2nd Embodiment and 3rd Embodiment is demonstrated. The absorber 4 in 2nd Embodiment and 3rd Embodiment is the structure of the continuous convex structure 6, and the continuous convex structure 6 and the absorptive core 5 compared with the absorber 4 in 1st Embodiment. The structure of partial joining is mainly different. Regarding the points that are not particularly described in the second embodiment and the third embodiment, since the description of the first embodiment is appropriately applied, the same components are denoted by the same reference numerals and the description thereof is omitted.

  In the absorber 4 in 2nd Embodiment, as shown in FIG. 19, the continuous convex part structure 6 is the 1st fiber layer 6a distribute | arranged to the surface sheet 2 side, and the 1st distribute | arranged to the absorber 4 side. The first fiber layer 6a and the second fiber layer 6b are partially heat-sealed to form a joint portion 62. The joints 62 are a large number of circular shapes, regularly formed in a dotted and zigzag manner, and the distance between the joints 62 is substantially constant. In addition, it is preferable that the joining parts 62 are arranged individually in a scattered manner, and the shape of each joining part 62 can be an ellipse, a triangle, a rectangle, a rhombus, or the like in addition to a circle. .

  The portion located between the joints 62 of the continuous convex structure 6, specifically, each region surrounded by the four joints 62 in the continuous convex structure 6 protrudes upward and has compression elasticity. A large number of convex portions 61 are formed. Each convex portion 61 has a dome shape, and the inside is filled with the constituent fibers of the continuous convex portion structure 6. In addition, the interface between the first fiber layer 6a and the second fiber layer 6b in the portion where each convex portion 61 is formed in the continuous convex structure 6 is not bonded but is in close contact.

The continuous convex structure 6 in the second embodiment is obtained, for example, by partially heat-sealing the first fiber layer 6a to the second fiber layer 6b in a predetermined pattern by hot embossing.
The heat fusion by heat embossing is, for example, an embossed surface (a peripheral surface of an embossing roll, etc.) in which a large number of embossed pins are regularly arranged in a laminate of the first fiber layer 6a and the second fiber layer 6b. The process is performed by melting the constituent fibers of the first fiber layer 6a and / or the second fiber layer 6b in the portion pressed against the first fiber layer 6a and thermally pressed by each pin. A large number of convex portions 61 are produced by deforming portions other than the joint portion 62 of the first fiber layer 6a into a convex shape.

  Since the continuous convex structure 6 is subjected to heat embossing, heat from the pin is also applied to the adjacent portion of the joint portion 62 in the first fiber layer 6a (because the peripheral surface of the pin abuts), Also in the adjacent portion, the constituent fibers of the first fiber layer 6a and the second fiber layer 6b are melted and solidified, and the constituent fibers are fused to each other. Therefore, the site | part adjacent to the heat sealing | fusion part of the convex part 61 is consolidated rather than the other site | part (near the top part) of the convex part 61, and the rigidity is improved.

In the absorbent body 4 in the second embodiment, the density ratio between the first fiber layer 6a and the second fiber layer 6b (first fiber layer 6a / second fiber layer 6b) is 1/1 to 1/3. It is preferable that the ratio is 1/1 to 1/2.
Such a density regulation is such that the liquid can easily pass through in the thickness direction of the continuous convex structure 6, and the capillary force of the second fiber layer 6 b is stronger than the capillary force of the absorber 4. Therefore, there is little liquid remaining in the second fiber layer 6b. Moreover, the displacement amount in the KES compression tester, that is, the compression work amount WC is increased, and high fit to the body can be realized.

  In the absorbent body 4 in the third embodiment, the continuous convex structure 6 is formed of a nonwoven fabric sheet that is a fiber assembly, as shown in FIGS. 20 (a) and 20 (b). The continuous convex structure 6 and the absorbent core 5 are partially heat-sealed, whereby a large number of joints 62 are formed. In the continuous convex structure 6, portions other than the joint portion 62 protrude in a direction toward the wearer's skin to form a large number of convex portions 61.

The convex portion 61 is formed discontinuously in the vertical and horizontal directions. That is, the convex portion 61 does not continuously extend in the specific direction of the absorber 4. More specifically, the convex portions 61 and the joint portions 62 are arranged in a staggered manner with a half-pitch shift with respect to the convex portions 61 and the joint portions 62 in adjacent rows.
The inside of the convex part 61 is not filled with fibers but is hollow. In addition, it can also be set as the structure with which the inside of the convex part 61 was filled with the fiber (not shown).
As in the third embodiment, the continuous convex structure 6 may be formed from a single nonwoven fabric sheet. Moreover, like 4th Embodiment shown in FIG.20 (c), the continuous convex structure 6 is hollow from the nonwoven fabric sheet of several sheets, for example, the 1st nonwoven fabric sheet 6c and the 2nd nonwoven fabric sheet 6d, for example. The convex part 61 may be formed.

Next, variations in the configuration of the absorbent core 5 will be described.
The absorbent core 5 shown in FIG. 21 (a) is formed from the piled fiber layer 51 of the pulp 52, and the superabsorbent polymer 53 is in the piled fiber layer 51 on the skin-facing surface side or non-skinned side. It is biased and carried on the opposite side. The abundance of the superabsorbent polymer may change continuously in the thickness direction of the absorbent core 5 or may change stepwise. The absorbent core 5 in which the superabsorbent polymer 53 is biased and embedded on the skin-facing surface side has a high spot absorbability of liquid, and is therefore suitable as an incontinence pad for light incontinence or an absorbent body for sanitary napkins. It is. The absorbent core 5 in which the superabsorbent polymer 53 is biased and embedded on the non-skin facing surface side has high liquid diffusibility and high liquid absorbability, and is therefore suitable as an absorbent body for disposable diapers. .

  The absorbent core 5 shown in FIG. 21B is formed from a web 55 of hydrophilic long fibers 56, and the superabsorbent polymer 53 is uniformly embedded and supported in the web 55. Also in the absorbent core 5 formed from the web 55 of the hydrophilic long fibers 56, the superabsorbent polymer 53 is biased and carried on the skin-opposing surface side or non-skin-facing surface side of the web 55. Can do. The absorbent core 5 formed from the web 55 of hydrophilic long fibers 56 has high liquid diffusibility and high liquid absorbency.

  The absorbent core 5 shown in FIG. 22 (a) has an embedded fiber layer 51 of the pulp 52 in which the superabsorbent polymer 53 shown in FIG. 3 is embedded and the superabsorbent polymer 53 shown in FIG. 21 (b). It consists of a laminated body with the web 55 of the supported long fiber 56 having hydrophilicity. The absorbent core 5 made of such a laminate has the advantage that the absorbent body is thinner and more flexible due to the flexible and high supportability of the long fiber web than that obtained by mixing a superabsorbent polymer with pulp. is there.

The absorbent core 5 shown in FIG. 22 (b) includes a fiber layer 51 of the pulp 52 in which the superabsorbent polymer 53 shown in FIG. 3 is embedded and the pulp 52 in which the superabsorbent polymer 53 is not embedded and supported. It consists of a laminated body with pile fiber layer 51 '. The pile layer 51 ′ of the pulp 52 in which the superabsorbent polymer 53 is not embedded and supported may contain a highly crimped pulp subjected to chemical treatment such as curly cellulose and 4-hydroxybenzoic acid (HBA). .
The absorbent core 5 shown in FIG. 22 (c) has a web 55 of hydrophilic long fibers 56 in which the superabsorbent polymer 53 shown in FIG. 21 (b) is embedded and supported, and the superabsorbent polymer 53 is embedded. It consists of a laminated body with the pile fiber layer 51 'of the pulp 52 which is not carry | supported.
When the fiber layer 51 ′ of the pulp 52 in which the superabsorbent polymer 53 is not embedded and supported is provided, there is an advantage that the absorber becomes thinner and flexible.

As mentioned above, although embodiment of the absorbent article of this invention was described, the absorbent article of this invention is not restrict | limited to embodiment mentioned above, Unless it deviates from the meaning of this invention, it can change suitably. .
The absorbent article of the present invention is not limited to a tape-type disposable diaper, and may be a pants-type disposable diaper. In addition to disposable diapers, it can also be applied to sanitary napkins, incontinence pads, and the like.
The shape of the convex portion may be a substantially Z-shape such that the loop-shaped convex portion 61 shown in FIG. 4 is cut in half in the horizontal direction.
Each configuration in the above-described various forms can be appropriately combined or omitted.

  Hereinafter, more specific examples (Examples 1 and 2) will be described.

[Example 1]
First, an acetate long fiber tow having crimps was prepared. The fiber diameter of this long fiber was 2.1 dtex, and the total fiber amount of tow was 25,000 dtex. After opening this tow with an air opening device under extension, a web in which a large number of discs are assembled at predetermined intervals around the axis and the web is spread between the receiving rolls. Got. Thereafter, the width was adjusted to 100 mm, and the speed was reduced and transferred onto a vacuum conveyor, and the web tension on the vacuum conveyor was relaxed. By this operation, an appropriate long fiber-long fiber distance and web thickness for supporting the superabsorbent polymer in the long fiber web are developed. At this time, the crimp rate of the long fibers in the web was 30%, and the number of crimps per 1 cm was 15. A superabsorbent polymer was sprayed on the web to obtain a layer in which the superabsorbent polymer particles were embedded and held in the spread web. The basis weight of the web was 26 g / m ² and the basis weight of the superabsorbent polymer was 110 g / m ² .

Furthermore, 100 parts by weight of the opened fluff pulp and 100 parts by weight of the superabsorbent polymer were uniformly mixed in an air stream to obtain a mixture having a total basis weight of 300 g / m ² . The web carrying these superabsorbent polymers and a layer of a mixture in which pulp / superabsorbent polymer was uniformly mixed were laminated (interlayer was bonded with a hot melt of 5 g / m ² ) to obtain a laminate. Next, the laminate was wrapped with a tissue paper having a basis weight of 16 g / m ² (the upper and lower surfaces of the laminate and the tissue paper were bonded with a hot melt of 5 g / m ² ) to obtain an absorbent core.
Next, after hot-melt pattern coating (5 mm in the longitudinal direction and 5 mm in the width direction) is applied to the tissue paper on the skin side, another continuous fiber web that becomes a continuous convex structure is overlaid on the absorbent core. Then, embossing was performed with an embossing roll and a smooth roll, and a convex portion was formed to obtain an absorbent body. At this time, the height of the convex portion from the absorbent core was 3 mm, and the interval in plan view of the convex portion was 5 mm in the longitudinal direction of the absorbent article and 5 mm in the width direction.

An air-through nonwoven fabric having a basis weight of 25 g / m ² was used as the surface sheet. The air-through nonwoven fabric is composed of a core-sheath type composite fiber (having a thickness of 2.1 dtex, surface-treated with a surfactant, and having liquid permeability) having a core of polypropylene and a sheath of linear low density polyethylene. It was. A porous film having a basis weight of 20 g / m ² as a backsheet, used was composite by bonding a polypropylene spunbond nonwoven fabric having a basis weight of 20 g / m ² hot melt 1.5 g / m ^2. The porous film is obtained by uniformly molding 100 parts by weight of a linear low density polyethylene resin having a density of 0.925 g / cm ² with 150 parts by weight of calcium carbonate and 4 parts by weight of an ester compound as a third component. And then uniaxially stretched twice in the longitudinal direction. Other than that, according to the manufacturing method of a normal disposable diaper, the disposable diaper of the structure shown in FIG.1 and FIG.2 was obtained. The absorber was arranged so that the orientation direction of the web coincided with the longitudinal direction of the diaper.

[Example 2]
First, an air-through nonwoven fabric having a width of 200 mm and a basis weight of 25 g / m ² (consisting of a core-sheath type composite fiber having a core made of polyethylene terephthalate and a sheath made of linear low-density polyethylene, and having a thickness as a sheet for forming convex portions. Is 1.7 dtex, surface-treated with a surfactant, and has liquid permeability). The width 250 mm is hydrophilized in a state of being sucked and held by a convex forming roll composed of a large number of adjacent gears. The spunbond-meltblown-spunbond nonwoven fabric (SMS) having a basis weight of 16 g / m ² was superposed on the central portion. At this time, both the convex forming roll and the receiving roll were heated to obtain a continuous convex structure in which only the bonding points were combined.

Next, the same continuous fiber as used in Example 1 was similarly opened and the width obtained was transferred onto the continuous convex structure on the vacuum conveyor while the speed was reduced. did. A superabsorbent polymer (260 g / m ²⁾ was sprayed on the web to obtain a layer in which the superabsorbent polymer particles were embedded and held in the spread web. Thereafter, both sides of the continuous convex structure were rolled up and wrapped with a web embedded with a superabsorbent polymer. Thereby, the absorber with which many convex parts were formed in the upper and lower sides of an absorptive core was obtained. Adjacent protrusions are offset from each other by 1/2 pitch, the height of the protrusions from the absorbent core is 3 mm, the spacing between the protrusions in plan view is 5 mm in the longitudinal direction of the absorbent article, and 5 mm in the width direction. Met.

FIG. 1 is a perspective view showing a disposable diaper that is a first embodiment of the absorbent article of the present invention. Fig.2 (a) is a schematic diagram which shows the disposable diaper shown in FIG. 1 highlighting the continuous convex structure in the absorber, and FIG.2 (b) is BB shown in Fig.2 (a). It is sectional drawing. FIG. 3 is a cross-sectional view showing an absorbent core in the absorbent body shown in FIG. FIG. 4 is a partially enlarged cross-sectional view of the absorbent body shown in FIG. FIG. 5 is a perspective view showing one manufacturing method of the absorbent body shown in FIG. FIG. 6 is a partially enlarged perspective view of the peripheral surface of the embossing roll used in the manufacturing method shown in FIG. FIG. 7 is a schematic development view (corresponding to FIG. 2A) showing another arrangement form of the convex portions in the continuous convex structure. FIG. 8 is a schematic development view (corresponding to FIG. 2A) showing another arrangement form of the continuous convex structure. 9A and 9B are diagrams showing another arrangement of the continuous convex structure, FIG. 9A is a schematic development view (corresponding to FIG. 2A), and FIG. 9B is a BB cross section shown in FIG. FIG. 2 is a diagram corresponding to FIG. FIG. 10 is a partially enlarged cross-sectional view (corresponding to FIG. 4) showing another partial bonding form of the convex portion to the absorbent core in the absorbent body. 11 (a) and 11 (b) are cross-sectional views (corresponding to FIG. 2 (b)) showing another arrangement of the convex portions in the absorber. 12 (a) to 12 (c) are cross-sectional views (corresponding to FIG. 2 (b)) showing another arrangement of the convex portions in the absorber. FIG. 13 is a schematic cross-sectional view showing a continuous convex structure having an inclined convex portion. FIG. 14 is a cross-sectional view (corresponding to FIG. 2B) showing an absorbent article having a hole in the top sheet. FIG. 15 is a perspective view showing a method of manufacturing the absorbent article shown in FIG. FIG. 16 is a cross-sectional view (corresponding to FIG. 2 (b)) showing an absorbent article having a hole in the top sheet. FIG. 17 is a perspective view showing a method for manufacturing the absorbent article shown in FIG. 16. FIG. 18 is a plan view showing a joint portion having a different configuration. FIG. 19 is a view showing an absorbent body according to the second embodiment, in which (a) is a sectional perspective view and (b) is a partially enlarged sectional view. 20A is a cross-sectional perspective view showing the absorbent body in the third embodiment, FIG. 20B is a partially enlarged cross-sectional view showing the absorbent body in the third embodiment, and FIG. It is a partial expanded sectional view which shows the absorber in embodiment. FIG. 21A and FIG. 21B are cross-sectional views (corresponding to FIG. 3) showing absorbent cores having different structures. 22 (a) to 22 (c) are cross-sectional views (corresponding to FIG. 3) showing absorbent cores having different structures.

Explanation of symbols

1 Absorbent article (disposable diaper)
2 Top sheet 21 Open hole 3 Back sheet 4 Absorber 41 Cover sheet 42 Open hole 5 Absorbent core 51 Stacked fiber layer 52 Pulp 53 Superabsorbent polymer 54 Buried dent 55 Web 56 Long fiber 6 Continuous convex structure 61 Convex 62 Joint 63 Opening

Claims (6)

An absorbent article comprising a top sheet, a back sheet, and an absorber interposed therebetween,
The absorbent body comprises an absorbent core and a continuous convex structure formed by a large number of convex parts,
The continuous convex structure is formed from a fiber assembly, and is provided by being partially joined to the topsheet side and / or the backsheet side in the absorbent core,
The protrusion has a height of 10 mm or less from the absorbent core,
A large number of the convex portions are inclined in one direction,
The absorbent body is an absorbent article having a compression work (WC value) of 0.98 cN · cm / cm ² or more by a KES compression tester in the thickness direction.   The absorbent article according to claim 1, wherein the partial joint between the continuous convex structure and the absorbent core is configured by the continuous convex structure being embedded in the absorbent core.   The absorbent article according to claim 1, wherein the fiber assembly is formed of long fibers. The absorbent article according to any one of claims 1 to 3 , wherein the absorbent core includes a web of hydrophilic long fibers, and a superabsorbent polymer is embedded and supported in the web. Wherein the continuous protrusions structures, superabsorbent polymers, absorbent superabsorbent does not have or contain contain a smaller range than the content of the polymer according to claim 1-4, wherein in said absorbent core Goods. The joint between the continuous convex structure and the absorbent core is composed of a large number of small joints arranged discontinuously, and the absorber is closed by being surrounded by a plurality of the small joints. Many areas are formed,
The long fibers in each closed region, substantially all of, the boundary between the other closure region located before and after the orientation direction, claim 3-5 which is fixed to the small junction An absorbent article according to any one of the above.

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