JP2011104059A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article which has high air permeability, does not easily get stuffy, is capable of quickly coping with the excretion of body fluid even when it is a large amount in one period and absorbing and holding it, and is soft with excellent fitness. <P>SOLUTION: The absorbent article includes a liquid permeable surface sheet arranged on a skin abutting surface side, a leakage prevention sheet arranged on a skin non-abutting surface side and an absorber interposed between both the sheets. The absorber has a plurality of holes passing through from the skin abutting surface side to the skin non-abutting surface side in a center excretion area. In the plurality of through-holes, an opening area in the plane view is fixed from the skin abutting surface side to the skin non-abutting surface side. In the plurality of through-holes, there are two big and small kinds of opening areas in the plane view on the skin abutting surface side. The through-holes having the big and small opening areas are formed to be close to each other and separately arranged. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

In the absorbent article, various improvements have been made in each of a direction in which the absorbent article is less likely to leak and is safe and a direction in which a comfortable feeling of use is realized. In order to obtain a comfortable feeling of use, the following three are important.
・ Soft feel.
・ There is no feeling of dampness or stickiness.
・ After liquid excretion, even if used for a long time, there is no stuffiness.
These proposals are made mainly by increasing the absorbency while maintaining the ease of deformation (ie, softness) of the product. Patent Document 1 discloses that a sanitary napkin is made of a composite material of an airlaid tissue material and a superabsorbent hydrogel absorbent material as an absorbent core having a high absorbency, or an absorbent foam or absorbent sponge is used. By being extremely thin and flexible, it is soft and non-sticky. Moreover, what suppresses a swelling is disclosed by using the microporous polyethylene film which escapes a vapor | steam from an absorptive core for the layer which contacts clothing.
In addition, in the past, several proposals have been made to use a hydrophilic foam material for the absorbent body of the absorbent article in an attempt to stabilize the shape and liquid absorption of the absorbent article. For example, by forming a continuous foam structure with a predetermined bubble diameter on the hydrophilic foam material, a hydrophilic foam material excellent in elastic recovery can be obtained (see Patent Document 2). As a result, the form is stable regardless of the wearer's movement and wearing time, and it is difficult to cause twisting or the like. In addition, since the foam structure is not easily crushed, once the liquid is taken into the liquid, it is difficult for the liquid to return, and the liquid can be stably held, so that the thickness can be reduced. Patent Document 3 discloses one in which three regions having different rigidity are formed by opening a foam material absorber. This opening is disclosed as a device for improving the three-dimensional fit of the napkin, but the liquid absorbency and the improvement of stuffiness are not particularly described. Further, there is no specific disclosure about the properties of the backsheet (leakproof sheet) used there.

JP 2007-252934 A JP-T-2-239863 JP 2008-529721 A

As described above, techniques in different directions are required for stabilization of absorbability of liquids and the like and improvement of wearing comfort, and it is difficult to achieve both. Therefore, in order to improve the stuffiness, it is necessary to secure a ventilation path through which water vapor can stably move over all of the surface sheet, the absorbent layer, and the leakproof sheet under various usage environments, and from the absorbent layer to the leakproof sheet. However, it is not easy to realize that it is important to devise a method of discharging only water vapor without discharging liquid to the outside. In the conventional device such as Patent Document 1 described above, a moisture-permeable film is used for the leak-proof sheet in contact with the absorption layer, and the effect of discharging a part of the body fluid permeating and diffusing into the absorption layer to the outside as water vapor is However, it did not secure a stable ventilation path. For example, when the absorption layer is uniformly moistened by the absorption of body fluid, the space (ventilation path) originally possessed by the absorption layer is lost by the body fluid filling. As a result, little or no breathability is lost at the body fluid absorption site. Even if a moisture permeable film is used, water vapor present on the napkin attachment site, particularly on the skin contact surface side around the body fluid discharge point, cannot penetrate the napkin and cannot move to the outside because the absorption layer cannot be vented. . On the other hand, the body fluid stored in the absorption layer evaporates from the skin contact surface side due to body temperature and is discharged as water vapor into the space, and as a result, the space becomes stuffy. Therefore, no matter how the moisture permeability or breathability of the leak-proof sheet is increased, it is difficult to improve the feeling of stuffiness.
In view of the above points, the present invention has a high breathability, is not easily stuffy, can absorb and retain quickly even if there is a large amount of fluid excretion at one time, and is a soft and well-fitted absorbent article The issue is to provide

  The present invention relates to an absorbent article having a liquid-permeable surface sheet disposed on the skin contact surface side, a leak-proof sheet disposed on the non-skin contact surface side, and an absorbent body interposed between the both sheets. The absorbent body has a plurality of holes penetrating from the skin contact surface side to the non-skin contact surface side in the central excretion region, and the plurality of through holes have a skin contact area in plan view. It is constant from the surface side to the non-skin contact surface side, and the plurality of through holes have two types of large and small hole areas in plan view on the skin contact surface side. The through-hole which has is provided in the vicinity of each other, and provides an absorbent article which is spaced apart.

  The absorptive article of the present invention has high air permeability, is hard to be stuffy, can be quickly absorbed even if there is a large amount of excretion of body fluid at one time, and has an excellent effect of softness and good fit.

It is the partially notched perspective view which showed typically the sanitary napkin as one Embodiment in this invention from the skin contact surface direction. It is sectional drawing of the II-II line cross section shown in FIG. It is a cross-sectional schematic diagram which expands and shows the mode of the liquid and hole in a sanitary napkin as a comparative example. FIG. 4 is a cross-sectional schematic view taken along the line IV-IV shown in FIG. 1 and showing an enlarged view of the liquid and holes in the sanitary napkin of the present invention. It is the top view which showed typically the absorber in this invention from the skin contact surface direction. It is sectional drawing which showed typically the case where time has passed more than after the excretion (ii) in FIG.

Hereinafter, preferred embodiments of the present invention will be shown and described in detail with reference to the drawings.
FIG. 1 is a partially cutaway perspective view showing a sanitary napkin 10 as an embodiment of an absorbent article according to the present invention from the skin contact surface direction. FIG. 2 is a cross-sectional view taken along line II-II shown in FIG.

  The sanitary napkin 10 according to this embodiment includes a liquid-permeable surface sheet 1 disposed on the skin contact surface side when worn, a moisture-permeable leak-proof sheet 2 disposed on the non-skin contact surface side, and both sheets. It has an absorbent body 3 made of a hydrophilic foam material interposed therebetween. The top sheet 1 and the leak-proof sheet 2 of the sanitary napkin 10 have the same shape in plan view, and are joined at the joint portion T by bonding, embossing, or the like.

  Although details of the top sheet 1, the moisture-permeable leak-proof sheet 2, and the absorber 3 will be described later, in this embodiment, the top sheet 1 quickly absorbs excreted body fluid and transmits it to the absorber, and the touch. From the viewpoint of goodness, a hydrophilic air-through nonwoven fabric is used. Moreover, as the moisture-permeable leak-proof sheet 2, a breathable moisture-permeable film is used as a single layer. As the absorber 3, a foam material having a hydrophilic open cell structure is used. Moreover, the adhesive (not shown) for fixing the sanitary napkin 10 to clothing is applied to the non-skin contact surface side of the leak-proof sheet 2. The sanitary napkin 10 is adhesively fixed to the user's clothes by the adhesive. The sanitary napkin 10 according to this embodiment is arranged with its top sheet side facing the wearer's skin contact surface and its longitudinal direction from the lower abdomen to the buttocks, in other words, the width direction of the left and right legs. Wear it in the direction of the connecting line.

FIG. 2 shows a cross section taken along line II-II across the excretion region W of the sanitary napkin 10 in FIG. Details of the excretion region W will be described later with reference to FIG. In the sanitary napkin 10 of the present embodiment, there is an opening 3a which is a hole penetrating from the skin contact surface side to the non-skin contact surface side in the absorbent body 3 interposed between the top sheet 1 and the leak-proof sheet 2. A plurality of the openings 3a are provided, and the opening area in a plan view is constant from the skin contact surface side to the non-skin contact surface side. Specifically, the sanitary napkin 10 is disposed only in the excretion region W surrounded by the width direction excretion region base line 3i in the width direction and the longitudinal direction excretion region base line 3s in the longitudinal direction. By providing the opening 3a in this region, the elastic repulsion at the center of the foam material in the absorbent body 3 is weakened, and it is possible to obtain flexibility when curving while drawing an arc here. Has the effect of increasing. Particularly important in the present embodiment is that there are two types of aperture areas in plan view, the substantially circular small aperture 3a ₂ and the large aperture 3a ₁ being formed in the vicinity of each other and spaced apart from each other. It is arranged. In the figure, the opening indicated by the solid line is the large opening 3a ₁ and the opening indicated by the broken line is the small opening 3a ₂ .

  The absorbent body, which is a porous body, has a breathability in which the continuous micropores become a ventilation path in a dry state and passes from the skin contact surface side to the non-skin contact surface side. Breathability is lost when absorbed inside. What is important here is that the sanitary napkin 10 in the present embodiment is an air-through nonwoven fabric, and the topsheet 1 has air permeability as well as the leak-proof sheet 2 and has moisture permeability and air permeability. Even in the body fluid absorption state, the liquid inside the surface sheet 1 quickly moves to the absorber due to the liquid drawing effect of the absorber 3, and the air permeability of the surface sheet 1 can be maintained relatively stably. More importantly, the absorbent body 3 in the present embodiment has an opening 3a having a specific shape that extends from the skin contact surface side to the non-skin contact surface side. Since the opening is overwhelmingly larger than the fine pores of the absorber and has a shape having the characteristics described later, even when excreted liquid is absorbed, the liquid is not filled to the end and functions as a ventilation chamber. Therefore, even if the breathability of the absorbent body is lost due to the filling of the body fluid in the excretion region W as described above, the opening 3a unique to the present embodiment penetrating the absorbent body provided there is stable ventilation. It becomes a path | route, and the moisture permeability and air permeability toward the non-skin contact surface side from the skin contact surface side can be ensured. As a result, the ventilation effect with the surface sheet 1 and the leak-proof sheet 2 is added, and a ventilation path through which water vapor can be stably moved is secured over the entire surface sheet-absorbent layer-leakage-proof sheet. Even in the state of sucking the liquid, in the excretion region W that tends to be moist, it can be ventilated from the body surface side to the outside of the clothes, and there is no stuffiness.

The action mechanism of the opening 3a as a ventilation chamber will be described in more detail.
First of all, as the significance of opening a hole such as 3a, such a large opening is easy to pass through the liquid at first glance. Therefore, it is imagined that the liquid enters first and is blocked when absorbing the liquid. The liquid absorbs and the liquid does not enter the opening 3a. The reason will be described later, but the pore diameter of the absorber 3 is overwhelmingly smaller than that of the opening 3a. For this reason, the capillary force is overwhelmingly large and the liquid can be easily sucked.
Next, as a factor that hinders the above effect, there are a blocking of the opening 3a due to excretion of a large amount of liquid exceeding the absorption rate of the absorber, a blocking of the opening 3a with a highly viscous liquid, and the like. The two common phenomena are that the excretory liquid remaining in the opening 3a blocks the through hole due to the surface tension of the liquid. In particular, a highly viscous liquid has a slow absorption rate to the absorber 3, and the liquid remains on the skin contact surface side of the absorber 3 for a long time. Therefore, in such a state, it may be difficult to ensure ventilation. However, according to the present embodiment, an effective ventilation path is ensured by the effect of the shape of the opening 3a described below.

  Here, the operation and effect peculiar to the sanitary napkin 10 of the present embodiment will be described with reference to FIGS. In the figure, the left side is before excretion (i), and the right side is after excretion (ii). An arrow A indicates the ventilation A, and the top sheet 1 and the leak-proof sheet 2 are not shown. In the drawing, the upper side is the skin contact surface side, and the lower side is the non-skin contact surface side. In addition, the shape shown by the one-dot chain line on the lower side is the shape of the hole in plan view.

FIG. 3 is an enlarged sectional view showing a case where a circular opening 33a is provided as a comparative example (corresponding to the opening 32 of the conventional absorber shown in FIG. 7). Before excretion (i), there is no obstruction in the opening 33a portion of the absorbent body 33 for comparison, and the ventilation A can pass from the skin contact surface side toward the non-skin contact surface side. However, after excretion (ii), in the opening 33a portion, the excretion liquid surface 5 where the excretion liquid stays due to the surface tension is formed as described above, and the passage of the ventilation A is prevented. As a result, a liquid reservoir (non-venting region) Q that does not function in ventilation performance is formed from the excretion fluid surface 5 to the non-skin contact surface side. Under such circumstances, the absence of ventilation on the skin contact surface side increases the humidity and tends to cause stuffiness. This is uncomfortable for the wearer and, if excessive, promotes rashes and proliferation of germs and is not hygienic.
Figure 4 is a IV-IV cross-section through the center point of the small apertures 3a ₂ and large opening hole 3a ₁ in FIG. According to the sanitary napkin 10 in the present embodiment, there is nothing to block the opening 3a before excretion (i), and the ventilation A passes from the skin contact surface side toward the non-skin contact surface side. Then, after excretion (ii), the aperture 3a portion forms a liquid pool Q in which the excretion liquid surface 5 is formed only in the small aperture portion 3a ₂ portions, while the excretory fluid film 5 is formed in the large aperture portion 3a ₁ portion. Not formed. Which is characteristic due to the opening 3a has a different small apertures 3a ₂ and large opening hole 3a ₁ of the area (pore diameter) in a plan view in this embodiment. Capillary force acting on the liquid acts greatly on the small-diameter hole. Therefore, when a large hole and a small hole coexist, the force with which the small hole pulls in the liquid is stronger, in other words, the smaller the hole, the faster the liquid is drawn. According to this embodiment, when a large amount of body fluid is temporarily excreted and diffused all at once into the excretion region W on the absorber 3, the body fluid is temporarily absorbed until the absorber 3 absorbs the body fluid. 3 remains on the skin side. In such a situation, in the present embodiment, the liquid is preferentially drawn into the inside of the hole from the small opening 3a _{2 having} a stronger capillary force than the large opening 3a ₁ . Even if the small opening 3a ₂ is blocked by the excretory liquid surface 5 and prevents the ventilation A ″, the large opening 3a ₁ remains selectively, and the ventilation from the skin contact surface side to the non-skin contact surface side. There exists an effect that the path | route of A 'can be ensured.

FIG. 5 is a cross-sectional view showing a case where more time has passed than after excretion (ii) in FIG. Immediately after excretion, as described in (ii) after excretion in FIG. 4, the body fluid is drawn into the small aperture 3a ₂ having a strong capillary force, and the small aperture 3a ₂ is filled with the body fluid. At this time, the small apertures 3a ₂ goes sequentially filled with body fluid excretion portion near the body fluid drawn into the small apertures 3a ₂ is the absorption b ₁ to the absorbent body 3 shown by the arrow in FIG. 5 It has begun. Also, it will be absorbed with the body fluid in the skin contact surface side not fit in small apertures 3a ₂ the transition to the small apertures 3a _2, or by absorption b ₂ from then on the surface of the absorbent body 3. The transition to the small opening 3a ₂ and the bodily fluid that has not been absorbed in the _two absorption paths b ₁ and b ₂ will partially flow into the large opening 3a ₁ . Here, since the wall surface area in the large aperture 3a ₁ is larger than the wall surface area in the small aperture 3a ₂ , the body fluid that has flowed into the large aperture 3a ₁ is quickly absorbed into the absorber ₃ . Even in the case where there is a large amount of excretion temporarily and body fluid flows into the large opening 3a ₁ , according to the present embodiment, there is an effect of early recovery of ventilation. Considering the cooperative action of small and large apertures as described above, the ratio of both can be designed and the ratio can be designed. For example, when dealing with small amounts such as falling items, menstrual blood When dealing with a relatively large amount, the size and ratio can be set as appropriate.

FIG. 6 is a plan view schematically showing the absorber in the present embodiment from the skin contact surface direction. The top sheet 1 and the leak-proof sheet 2 are not shown. In the drawing, L is a plan view further enlarging the opening 3a. In the present embodiment, the absorber 3 is substantially rectangular in plan view. In the absorbent body 3, an excretion region W surrounded by a width direction excretion region base line 3i and a longitudinal direction excretion region base line 3s is set at a position deviated to the front side in the longitudinal direction, and an opening 3a is formed in the region. It has been subjected. The “front side” herein refers to the walking direction side of a person, and in the worn state, the front longitudinal direction excretion region base line 3s ₁ is worn on the abdomen, and the rear longitudinal direction excretion region base line 3s ₂ is worn on the buttocks. In the present embodiment, the “excretion area” refers to a portion that directly receives excretion of menstrual blood or vaginal discharge and the vicinity thereof. Therefore, if there is a reasonable amount of excretion, the absorbed liquid may diffuse by capillary action over time and exceed this region. Although the position of the excretion area | region W is not specifically limited, In order to exhibit the favorable ventilation | gas_flowing performance mentioned above as the sanitary napkin 10, 20-60 mm is preferable in the front side longitudinal direction nonexcretion length, and 25-45 mm is still more preferable. The lengthwise excretion region length C is preferably 45 to 120 mm, and more preferably 55 to 100 mm. The rear longitudinal non-excretion length R is preferably 30 to 150 mm, and more preferably 40 to 120 mm. Further, the non-excretion lengths Sr and Se in the width direction are each preferably 0 to 30 mm, and more preferably 5 to 20 mm. The width direction excretion region length Sc is preferably 20 mm or more, and more preferably 25 to 45 mm. Moreover, in order to exhibit favorable deformation | transformation fit property in the excretion area | region W, it is preferable that the front side non-excretion length F is 15-30% with respect to the absorber 3 full length, and is 18-25%. More preferably. The lengthwise excretion region length C is preferably 25 to 60%, and more preferably 35 to 50%. The rear side non-excretion length R is preferably 20 to 65%, more preferably 30 to 50%. Further, the width direction non-excretion lengths Sr and Se are preferably 0 to 10% and more preferably 2 to 7% with respect to the entire width of the absorber 3.

In the present embodiment, the excretion region is substantially rectangular, but it is also preferable to select an arbitrary shape within a range that satisfies the spirit of the present application. For example, by making the excretion region into an elliptical shape, it is easy to match the expanded shape of the body fluid, and the effect of further increasing the flexibility of the portion corresponding to the crotch portion is exhibited. In addition, by making the excretion region into a constricted shape (weight or bee shape is also possible), it is possible to give a deformability that easily fits the underfoot. The preferred absorber size can be selected depending on the type of product (for example, a light day napkin, normal size, night size), etc., but the preferred absorber longitudinal length is 120 to 450 mm, More preferably, it is 140-370 mm. Preferably, the length of the absorbent body in the width direction is 40 to 120 mm, more preferably 45 to 100 mm, and a “necked shape” in which the portion corresponding to the crotch is narrowed by 10 to 40% of the total width is selected to improve fit. Is also preferable. Moreover, it is preferable that the preferable absorber thickness is 10 mm or less in the thickness under a peacock dial gauge 2.5 g / cm ² load, and it is more preferable that the thickness is 3 to 7 mm from the viewpoint of soft and high fit. In order to further improve the fit, it is also preferable to crush the peripheral area excluding the excretion area to a predetermined thickness by a method such as hot pressing, to thicken the excretion area and to relatively thin the peripheral area.

The diameter d ₂ of the small aperture 3a ₂ for effectively functioning the small aperture 3a ₂ and the large aperture 3a ₁ in the present embodiment is preferably 0.3 to ₂ mm, preferably 0.5 to More preferably, it is 1.6 mm. Large opening hole 3a ₁ preferably has a diameter _{d 1} of 1.2 times to 5.0 times the diameter _{d 2} of small apertures 3a _2, have a diameter _{d 1} of 1.5 to 3.0 times Further preferred (see FIG. 6). By making both the openings have a difference in diameter within this range, the large opening 3a ₁ is likely to remain as an opening during absorption of body fluid, and the liquid is liable to migrate in preference to the small opening 3a ₂ . The large aperture 3a ₁ and the small aperture 3a _{2 of the} present embodiment are formed in the vicinity of each other and are spaced apart from each other. Preferably the distance between the centers _{d 3} between small apertures 3a ₂ and large opening hole 3a ₁ is 1.0～6.0Mm, further preferably 1.3～4.5Mm. By setting the distance within this range, the large aperture 3a ₁ and the small aperture 3a ₂ are easily related, and the liquid in the vicinity of the large aperture 3a ₁ is also likely to move in preference to the small aperture 3a ₂ . The distance dr (see FIG. 4) between the large aperture 3a ₁ and the small aperture 3a ₂ is preferably 0.5 to 4 mm, and more preferably 1 to 3 mm. The small aperture array locus 3a ₃ indicates the region of the center distance, and the number of small apertures 3a ₂ arranged thereon, that is, one small aperture is preferably 1 to 8. More preferably, it is 5-4. The intervals between the small apertures 3a ₂ on the small aperture array trajectory 3a ₃ are arranged at equal intervals on the circumference according to the number, or arranged while waiting for the bias in a predetermined direction, It is preferable that it is appropriately determined according to the use situation.

In order to control the above-described liquid drawing force and to effectively develop the effect of securing the ventilation path, the area ratio in the excretion region W between the large opening 3a ₁ and the small opening 3a ₂ , that is, (the large opening 3a ₁ area D _max / small aperture 3a ₂ area D _min ) is preferably 1.7 or more, more preferably 1.9 to 12.0. The large opening 3a ₁ area D _max is the area of the large opening 3a ₁ in plan view, and the small opening 3a ₂ area D _min is the area of the small opening 3a ₂ in plan view. Further, it is preferable that three or more kinds of openings having different sizes are randomly distributed. In this case, it is more preferable in view of the division of roles to have two distributions near the small aperture that contributes to the storage of the liquid and near the large aperture that contributes to securing the ventilation path. Specifically, when the opening area or opening diameter of each hole is measured and the frequency distribution is plotted, it is preferable that the opening area or opening diameter frequency distribution has two peaks. In consideration of the opening of a preferable size that contributes to deformability and flexibility, the number of peaks may be 3 to 4. In addition, it is preferable for the roles to be distributed randomly, but the small hole array locus 3a ₃ in the distribution is arranged at equal intervals on the circumference according to the distribution, It is also possible to arrange them while waiting for the bias in the direction of the above, or arrange them along a specific pattern.

In order to function effectively as a ventilation path that is not completely closed, the opening 3 a needs to have a lower capillary force than the foam material in the absorbent body 3. A preferable aperture diameter is larger than the average distance between the skeleton of the foam material and the top sheet 1. The interfiber distance of the topsheet 1 is preferably 200 to 400 μm. Further, the average distance between the skeletons of the foam material in the absorbent body 3 is preferably 400 μm or less, more preferably 200 μm or less, and more preferably in the range of 10 to 150 μm. As a result, the smaller the average distance, the greater the capillary force, and it is easier to draw the liquid from the top sheet 1. On the other hand, the larger the average distance, the smaller the resistance to fluid flow and the easier movement of the liquid. Therefore, the foam structure capable of absorbing in a balanced manner preferably has an average distance between skeletons of 10 to 400 μm. In addition, the distance between fibers shows the expansion visual distance (average value) between fibers measured in the uncompressed state, and the measuring method is shown below.
[Measurement of distance between fibers]
1: An enlargement observation system capable of displaying an actual size, preferably printable, such as an electron microscope or a microscope is used. The measurement is performed at a magnification at which the gap between the fibers is sufficiently visible (usually selectable at 50 to 200 times).
2: The measurement sample is cut into a size that can be placed on the sample stage using a razor or the like so as not to be compressed in the thickness direction, and is enlarged and displayed on the monitor as described above.
3: Arbitrarily select two adjacent fibers on the screen, measure the distance between the fibers on the screen or in a direction substantially perpendicular to the direction in which the fibers extend, and calculate the scale from the actual size display. Find the distance between fibers.
When measuring, if it is equipped with a distance measuring function between two points, such as KEYENCE brand name: Hiscope, select two points so that they are approximately perpendicular to the two fibers, and display the actual distance. This method is also simple and suitable. The measurement is performed between any 20 sets of fibers on the screen, and the average value is taken as the interfiber distance.
The average distance between skeletons indicates an enlarged visual distance (average value) between skeletons of the foam material measured in an uncompressed state, and the measurement method is shown below.
1: Apparatus and sample preparation are in accordance with fiber distance measurement.
2: Similarly, it is basically to measure the distance between two arbitrary skeletons. However, in the foam material, the basic unit created by the skeleton as its name often can be regarded as a bubble (circle or ellipse) shape. In this case, voids formed by some skeletons are regarded as circles or ellipses, and the equivalent circle diameter or equivalent ellipse diameter (short axis diameter) is obtained as the distance between the skeletons. As for the distance between the skeletons, any 20 points are measured, and the average value is used as a representative value. Note that the measurement magnification can be arbitrarily selected in view of the size of the foam (foam) of the foam material, and is usually about 100 to 500 times.

  Moreover, in order to draw in the liquid quickly and hold it firmly, the average distance between the skeletons on the skin contact surface side of the absorbent body 3 is increased to absorb the liquid quickly, and the average distance between the skeletons on the non-skin contact surface side. A mode in which the liquid is kept small and firmly held is also preferable. The form may be formed by laminating two or more foam material sheets having an average distance between skeletons. At this time, the foam materials can be simply overlapped with each other. However, the hot-melt adhesive is subjected to thermocompression bonding by a method such as spiral spray coating with a hot melt adhesive, or a dot-like or linear pattern such as pin embossing. They can be integrated with each other, or can be connected by a method of using both together. It is also possible to use the polymer in the foam material by a method such as spraying a water-absorbing polymer between the layers. In any case, it is most effective to form the opening 3a so as to penetrate through the whole after overlapping the foam materials. Alternatively, the average distance between the skeletons may be continuously reduced from the skin contact surface side to the non-skin contact surface side by a method such as foaming condition control or thermal compression.

  The absorbent article of the present invention is not limited to the above-described embodiment, and the present invention can be applied to disposable diapers, incontinence pads, incontinence liners, and the like. Furthermore, it is effective not only for menstrual blood, orimono, but also for urine, loose stool, and the like. The size, shape, arrangement pattern, and the like of the openings 3a are not limited to the above-described embodiment, and are preferably determined as appropriate according to usage conditions and requirements. In addition to the top sheet 1, the absorber 3, and the leak-proof sheet 2, it is also preferable to appropriately incorporate a material that does not impair air permeability. For example, by interposing a hydrophilic sheet such as a nonwoven fabric between the top sheet 1 and the absorbent body 3, the temporary retention function of the liquid is improved, and even a large amount of liquid or highly viscous liquid adheres to the skin. It is possible to prevent. Moreover, the said hydrophilic sheet diffuses a bodily fluid planarly, and delivers it slowly to the absorber 3 of a wider range. As a result, the absorber 3 does not need to receive the liquid instantaneously in a narrow range, and the risk of blocking the opening 3a is reduced. Furthermore, it is also preferable that the leak-proof sheet 2 is adhered to the non-skin contact surface of the absorbent body 3 with an adhesive.

  The material of the top sheet 1, the absorbent body 3 and the leak-proof sheet 2 of the sanitary napkin of the above embodiment, the conditions in the production method, and the dimensional specifications of the product are not particularly limited. Reference can be made to the matters described in the publication.

  The surface sheet 1 in the present embodiment is preferably a hydrophilic thermal bond nonwoven fabric from the viewpoint of promptly absorbing excreted bodily fluid and transmitting it to the absorbent body and from the viewpoint of good touch, and particularly preferably an air-through nonwoven fabric. The topsheet 1 is preferably a thermoplastic resin fiber that has been subjected to a hydrophilic treatment, and the fiber is a fiber that has undergone a three-dimensional crimp such as a secondary crimp or a tertiary crimp. Specifically, polyethylene, polypropylene, polyester, nylon, and composite fibers thereof are prepared, and various hydrophilizing agents are applied at a stage before cutting into a predetermined length to form staples. Hydrophilic agents include various alkyl sulfonates represented by α-olefin sulfonates, acrylates, acrylate / acrylamide copolymers, ester amides, ester amide salts, polyethylene glycol and derivatives thereof, water-soluble Hydrophilic treatment with a hydrophilizing agent known to those skilled in the art, such as a reactive polyester resin, various silicone derivatives, various sugar derivatives, and mixtures thereof, can be used.

The leak-proof sheet 2 can be a moisture-permeable film alone, a laminate of a film and a nonwoven fabric, or a water-repellent nonwoven fabric (such as SMS or SMMS). It is most preferable to use a moisture permeable film alone as a leak-proof material from the viewpoint of cost and matching with an anti-displacement adhesive. As the film material in this case, a film obtained by melt-kneading a thermoplastic resin and an inorganic filler that is not compatible with the thermoplastic resin and extruding the film to a predetermined size to make fine holes, or essentially moisture The non-porous film which is highly compatible and can discharge water vapor, such as a permeable membrane. In order to realize a leak-proof layer that sufficiently exhibits the performance of moisture discharge related to the present invention and does not ooze out moisture, the moisture permeability should be in the range of 0.7 to 3.0 g / 100 cm ² hr. Is preferable, and it is still more preferable that it exists in the range of 1.0-2.5. From the standpoint of sufficiently improving the smoothness, it is most preferably from 1.5 to 2.5. Moreover, in order to be able to use without trouble, such as a tear of a film, a film basic weight is 18-70 g / m < ² >, More preferably, it is 25-60 g / m < ² >. Moreover, a preferable inorganic filler compounding quantity is 30-65 mass% as a mass% of the filler with respect to the mass of the whole film, More preferably, it is 40-60 mass%.

  The absorber 3 is preferably a foam material having a hydrophilic and open cell structure for the following reason. Because it is soft and elastic, it is difficult to twist and fits the body easily. Even if body pressure or operation deformation is applied, the cell (bubble) is not easily deformed, so that it is difficult for the liquid to return or move. That is, stable absorption is possible. More specifically, the absorber 3 has a three-dimensional skeleton structure, and is preferably essentially hydrophilic or a structure subjected to hydrophilic treatment. The material is not particularly limited and can be widely used. Is possible. For example, a porous body made of a synthetic polymer such as polyurethane, polystyrene, polyethylene, polyester, polyvinyl alcohol, butadiene styrene rubber (SBR), nitrile butadiene rubber, a porous body made of a polysaccharide such as cellulose, or an inorganic substance such as diatomaceous earth. A porous body etc. are mentioned. Also, the porous structure forming method includes foam formation by chemical foaming such as urethane foam, supercritical foaming, physical foaming by suction of gas such as carbon dioxide and nitrogen, void formation by extraction method, pore layer emulsion foam, etc. Various foam forming methods such as foam formation in the polymerization process can be used. Furthermore, the hydrophilicity of the foam material is selected by a method such as selecting a hydrophilic polyol as one of polymerizable monomers in urethane in addition to selecting an essentially hydrophilic material such as cellulose or diatomaceous earth. A hydrophilic foam material is obtained. On the other hand, it is also possible to hydrophilize the hydrophobic foam material with various hydrophilizing agents like the surface sheet. It is also possible to use for the absorbent body 3 a fiber aggregate such as air laid tissue or non-woven fabric, cotton-like pulp, and an absorbent sheet formed by combining these with a superabsorbent polymer. It is also possible to use as the absorbent body 3 a superposed sheet obtained by superimposing porous foam materials and having openings 3a, but these and hydrophilic foam materials have the following differences in the liquid distribution state and mobility. The fiber gaps or voids of the fiber assembly are linearly continuous, and the voids are liable to be crushed, so that the liquid can be easily diffused uniformly into the absorption layer, and the liquid can be easily moved and returned by the body pressure. Produce. On the other hand, the hydrophilic foam material has a stable form as described below and the foam structure itself is not easily crushed, so that the liquid tends to stay in one place, and liquid movement and liquid return due to body pressure hardly occur. Therefore, when the absorbent body 3 includes the fiber assembly, even when the liquid is stored so that the opening 3a becomes a gap and functions as a ventilation chamber, it is stored in the fiber assembly by the user's body pressure or operation deformation. Considering that the liquid that has been leaked into the opening 3a and closing the opening, a configuration in which the hydrophilic foam material alone or a combination of the hydrophilic foam material and the superabsorbent polymer is most preferable.

  Regardless of the body fluid absorption state, in order to secure a ventilation path from the surface to the leak-proof sheet, it is important that the liquid is quickly moved from the surface sheet to the absorbent body so that no liquid remains on the surface sheet. For this purpose, it is important to increase the liquid pull-in force of the absorber, so-called capillary force, from the top sheet. Specifically, in the hydrophilization treatment described above, the amount of the hydrophilic agent coating on the absorber side is increased, or the average distance between the skeletons of the foam material is designed to be smaller than the distance between the surface sheet nonwoven fabric fibers. For example, the amount of hydrophilic agent applied to the top sheet is 1% by mass, and the amount of hydrophilic agent applied to the foam material is 3% by mass. Or the method of making the average distance between frame | skeletons of foam material into 400 micrometers or less is preferable, and it is still more preferable to use both together. Moreover, it is preferable that the adhesive for fixing the sanitary napkin 10 to the underwear is not a thin film, and the coating pattern is selected so as not to impair the moisture permeability or breathability of the leak-proof sheet 2. Specifically, pattern coating such as eliminating the adhesive coating at positions corresponding to the excretion area, forming a pattern in which the linear and slit patterns are spaced apart, and scattering a discrete dot pattern over the entire surface, etc. Is preferred. Further, in order to avoid the surface sheet 1 that tends to deteriorate the air permeability when wet, and to ensure a higher air permeability, the surface sheet 1 was formed with a through hole and formed in the through hole and the absorber 3. It is also preferable that the through hole (open hole) is in the same position.

DESCRIPTION OF SYMBOLS 1 Surface sheet 2 Leak-proof sheet 3 Absorber 3a Opening 10 Sanitary napkin

Claims (4)

  A liquid-permeable surface sheet disposed on the skin contact surface side, a leakproof sheet disposed on the non-skin contact surface side, and an absorbent article having an absorbent body interposed between the two sheets, The absorbent body has a plurality of holes penetrating from the skin contact surface side to the non-skin contact surface side in the central excretion region, and the plurality of through holes have a non-open area in plan view from the skin contact surface side. The plurality of through-holes are constant toward the skin contact surface side, and there are two kinds of large and small aperture areas in plan view on the skin contact surface side, and the through holes having the large and small aperture areas Are absorbent articles formed in the vicinity of each other and spaced apart from each other. The ratio (D _max / D _min ) between the smallest opening area (D _min ) and the largest opening area (D _max ) of the plurality of through holes in plan view on the skin contact surface side The absorptive article according to claim 1 in which was made 1.7 or more.   The absorbent article according to claim 1, wherein the absorbent body is made of a hydrophilic foam material.   The absorbent article according to any one of claims 1 to 3, wherein a through hole is formed in the surface sheet, and the through hole and the through hole formed in the absorber are formed at the same position.

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