JP5466488B2 - Absorbent articles - Google Patents

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 provides a liquid-permeable surface sheet disposed on the skin contact surface side, a moisture-permeable leak-proof sheet disposed on the non-skin contact surface side, and an absorbent body interposed between the two sheets. The absorbent article has a plurality of holes penetrating from the skin contact surface to the non-skin contact surface in the excretion region, and the through-hole wall surface, the skin contact surface, and the non-skin contact In the cross-sectional shape formed by the surface, the line formed by the wall surface is inclined with respect to the normal line of the skin contact surface, and the wall area (Aa) of the through hole is greater than the wall area (Ab) of the virtual columnar through hole. The present invention provides an absorbent article characterized by having a large shape.

  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. It is a cross-sectional schematic diagram which expands and shows the mode of the liquid and hole in the sanitary napkin of this 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 the absorber as another embodiment (Embodiment 2) in this invention in the same position as the II-II line cross section in FIG. It is a cross-sectional schematic diagram which expands and shows the mode of the liquid and hole in Embodiment 2. It is sectional drawing which showed the absorber as another embodiment (Embodiment 3) in this invention in the same position as the II-II line cross section in FIG. It is a cross-sectional schematic diagram which expands and shows the mode of the liquid and hole in Embodiment 3.

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, a through-hole 3a that is a hole penetrating from the skin contact surface side to the non-skin contact surface side through the absorbent body 3 interposed between the top sheet 1 and the leak-proof sheet 2 is provided. A plurality are arranged. 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 through hole 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 curved by drawing an arc here. Has the effect of increasing. The through-hole 3a in the present embodiment is formed in a circular shape larger than the skin surface opening 3a ₁ on the skin contact surface side and the skin surface opening 3a ₁ formed in a circular shape in plan view on the skin contact surface side. It is a hole having a non-skin surface opening 3a ₂ and penetrating in the thickness direction of the absorber 3 so as to connect both openings, and has a substantially truncated cone shape. Therefore, the through-hole 3a has a substantially trapezoidal shape spreading toward the non-skin contact surface side in a sectional view.

  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. The body fluid virtual transition region Q is indicated by a halftone dot. The body fluid virtual transition region Q is a transition region of natural fluid excreted in such a situation in which the skin surface side of the absorber 3 is disposed on the upper side in the direction of gravity and the non-skin surface side is disposed on the lower side. ing. That is, the virtual body fluid tries to migrate towards the separate strong if diffuse force or the like is no by projecting the shape of the skin surface openings 3a ₁ linearly in the non-skin side region. The body fluid virtual transition region Q in the present embodiment schematically shows the movement of body fluid as a simple region from the viewpoint of making it easier to understand the features of the present invention. Further, a line that projects the shape of the skin surface opening 3a ₁ linearly on the non-skin surface side is a projection base line (normal line of the skin contact surface) Qi, and the open wall surface in the cross-sectional view of the through-hole 3a other than the columnar shape Let P be the intersection of D and the normal Qi of the skin contact surface (see FIG. 4). Here, the normal of the skin contact surface includes not only a straight line orthogonal to the tangential plane of the cross section but also a case orthogonal to the plane. As described above, in the present embodiment, the opening wall surface of the cross section (longitudinal section) formed by the wall surface of the opening 3a, the skin contact surface, and the non-skin contact surface with respect to the normal line of the skin contact surface. A line Di formed by D is inclined. In other words, the normal line Qi of the skin contact surface and the line Di formed by the open wall surface intersect each other at any tampering point. The top sheet 1 is not shown, and the leak-proof sheet 2 is indicated by a one-dot chain line. In the drawing, the upper side is the skin contact surface side, and the lower side is the non-skin contact surface side. Furthermore, the air region S is shown in FIG. The air region S can be regarded as a surplus volume integral of the actual through hole with respect to the body fluid virtual transition region Q. In this embodiment, when the air region S is viewed from the skin surface opening 3a ₁ to the non-skin contact surface side in the thickness direction, the opening area increases by an amount with respect to the opening 3a ₁ (minimum area). Shows how to do.

FIG. 3 is an enlarged cross-sectional view showing a case where a circular through hole (columnar through hole) 33a is provided as a comparative example. Opening shape in plan view of the skin surface opening 33a ₁ and the non-skin face opening 33a ₂ are the same circular shape, and the normal Qi and opening wall surface D of the skin contact surface corresponds. When a large amount of excretion is made in such a shape, the bodily fluid that has not been completely absorbed by the absorbent body 3 stays in the through-hole 33a and hinders ventilation. Further, when the body fluid is filled in the through hole in the shape as in this comparative example, the absorption to the hole wall surface D is hindered, and the recovery of ventilation is delayed. Thereby, the time which cannot function in ventilation performance from the skin contact surface side to the non-skin contact surface side lasts for a long time. 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.
In contrast, according to the sanitary napkin 10 in the embodiment shown in FIG. 4, when a large amount of excretion is made, the body fluid that could not be absorbed into the absorbent body 3 in the through hole 3a through the skin surface openings 3a ₁ Flows in. The body fluid flows in and passes through the skin opening 3a ₁ to form a region shown in the body fluid virtual transition region Q in the figure, and is sequentially accumulated on the lower surface. In detail, the through-holes 3a are better than the skin surface opening 3a ₁ of the non-skin face opening 3a ₂ has a larger opening area, an area which body fluid corresponding to the air region S to be inflated to form an air gap becomes surplus area. Actually, when the absorber 3 is hydrophilic, the liquid transferred to the lower surface side spreads along the opening wall surface D and forms a substantially circular gap corresponding to the air region S in the central portion. When observed as a whole in the thickness direction, the air gap has a shape similar to a truncated cone constricted upward at the center of the opening. Furthermore, since it is more stable that the body fluid moves to the pores of the absorber 3 from the inside of the opening, the body fluid moves from the opening wall surface D to the absorber 3 side.
At this time, the through hole 3a in the present embodiment has a cross-sectional shape from the skin contact surface to the non-skin contact when the opening area on the skin contact surface side of the through hole 3a is the same in the wall area (Aa). It is made larger than the columnar virtual wall area (Ab) of the through-holes that are linear toward the surface (Aa> Ab). In other words, than the projected baseline Qi ridge line of plainly speaking aperture wall D in line with the cross-sectional shape projected to the non-skin side to the shape of the skin surface openings 3a ₁ straight through-holes 3a of this embodiment The wall area becomes longer, and the difference becomes the square of the ratio. Therefore, the area where the bodily fluid comes into contact can be significantly increased in the present embodiment as compared with the comparative example, and the absorption into the absorbent body 3 is effective and quick. At this time, the skin surface opening 3a ₁ in the through hole 3a has a smaller opening area than the non-skin surface opening 3a _2, so that the capillary force of the through hole is smaller in the non-skin surface opening 3a ₂ as well. Improves the effect of promoting absorption. That is, the force of retaining the liquid in the through-hole becomes weaker toward the non-skin surface opening 3a ₂ side, so that the liquid suction through the wall surface D becomes easier. Note that the wall area (Ab) of the virtual columnar through-hole is a columnar shape that linearly penetrates the same opening as the opening area on the skin contact surface side of the through-hole having the wall area (Aa) in a direction perpendicular thereto. When the through-hole is assumed, it means the wall area of the columnar through-hole.

Furthermore, the air region S is not only a region that draws more body fluid into the inside than the shape in which the shape of the skin surface opening 3a ₁ is linearly connected to the non-skin surface side, but also has moisture permeability or air permeability. By cooperating with the leak-proof sheet 2, it also functions as a ventilation path. As described above, the leak-proof sheet 2 of the present embodiment has moisture permeability or air permeability, and when there is no body fluid in the through-hole 3a, the skin surface side moisture permeability (ventilation) with high humidity from the skin surface side. v ₁ occurs, to reach the barrier sheet 2 through the through hole 3a. Therefore, while the movement of the liquid is blocked, a non-skin surface side moisture permeability (ventilation) v ₂ that passes through the leak-proof sheet 2 and exits to the non-skin surface is generated, and a series of moisture permeability or ventilation is performed (see FIG. 2). . According to the present embodiment, when the body fluid virtual transition region Q and the air region S are provided in the through-hole 3a, the series of moisture permeability or ventilation works well to prevent the body fluid from being blocked more effectively. Can do. This makes it difficult to block the inside of the through hole 3a, and in addition to the above-described effective absorption performance, it is possible to ensure and recover a quick air permeability.

FIG. 5 is a plan view schematically showing the absorbent body in this embodiment from the skin contact surface direction. The top sheet 1 and the leak-proof sheet 2 are not shown. 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 a through hole 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. The position of the excretion region W is not particularly limited, but considering that the good ventilation performance described above as the sanitary napkin 10 is effectively exerted, the front longitudinal non-excretion length F is preferably 20 to 60 mm, and preferably 25 to 25 mm. More preferably, it is 45 mm. 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. In other words, it is preferably a region of ¼ point to ¾ point when the length in the longitudinal direction of the absorber is divided into four equal parts, and in the region of ¼ point to ½ point. More preferably it is. 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.

Preferably the diameter _{d 1} of Hadamen opening 3a ₁ is 0.5~4.0mm for skin face opening 3a ₁ and the non-skin face opening 3a ₂ to function effectively in the present embodiment, 1-2 More preferably, it is 5 mm. Preferably the diameter _{d 2} of the non-skin-face opening 3a ₂ is 1 to 6 mm, and further preferably from 1.5 to 5.0 mm (see FIG. 4). Further, the inclination angle of the hole wall surface D is preferably 10 ° or more, and more preferably 15 to 45 °. Here, the inclination angle is an angle having an intersection P formed by the projection base line Qi and the hole wall surface D as a vertex. The ratio (Aa / Ab) between the wall area (Aa) of the through hole 3a of this embodiment and the wall area (Ab) of the columnar through hole that linearly penetrates the through hole 3a toward the non-skin contact surface is 1. It is preferably 2 or more, and more preferably 1.5 to 4.0.

Although the method of producing the through-hole 3a in this embodiment is not specifically limited, The skin surface side of the absorber 3 is radially extended in planar view, and only the skin surface side is expanded. In the extended state, a through-hole having a size of the non-skin surface opening 3a ₂ is formed in the thickness direction by a through-hole forming device such as a rotary die cutter or a pin roll. Linearly hollowed through holes is diameter of was stretched portion by returning the stretched state of the skin surface side reduced Hadamen opening 3a ₁ is formed, non-skin face opening 3a of the non-skin side which does not stretch ₂ is formed as a hole diameter as it is, and a portion between both openings becomes a through-hole having a truncated cone shape as a whole by connecting both openings linearly. By designing the extended state, the through hole 3a having a desired inclination angle can be formed. In addition, it is also preferable to cut the spiral groove in the open wall surface D of the through hole 3a of the present embodiment to increase the wall area and expand the surface in contact with the body fluid, thereby increasing the absorption efficiency. Moreover, after forming the columnar through hole as shown in FIG. 3, the skin surface side may be heated and thermally contracted at a desired ratio to form a truncated cone shaped through hole.

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. This form may be formed by laminating two or more sheets made of foam material 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, in order to form the through hole 3a, it is efficient to penetrate 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.

Next, regarding the sanitary napkin as the second and third embodiments of the present invention, differences from the first embodiment will be mainly described with reference to FIGS. 6 (Embodiment 2) and 8 (Embodiment 3) are cross-sectional views showing the absorber at the same position as the cross section taken along line II-II in FIG. 1, and FIGS. It is a cross-sectional schematic diagram which expands and shows the state of a liquid and a hole, respectively.
In 2nd Embodiment, as shown in FIG. 6, it is set as the shape which inclined diagonally toward the non-skin contact surface from the skin contact surface in the cross-sectional shape of an absorber. The absorbent body 3 has a two-layer structure of an upper layer foam 32 and a lower layer foam 31 in which two foam materials are bonded together at a boundary B with a hot melt adhesive, and the arrangement position in the plan view of the through-hole 3a and the excretion region W Is the same as in the first embodiment. Through hole 3a in the present embodiment, the shape in plan view of the skin surface openings 3a ₁ and the non-skin face opening 3a ₂ are the same circular shape. After the body fluid in such a through hole 3a is drawn into the skin surface opening 3a _1, opening wall surface D and the body fluid present in the gravity direction is in contact, and be absorbed from the contact surface. What is important here is that the perforated wall surface D or the longitudinal section line Di formed by it is a normal line (projection base line) Qi of the skin contact surface obtained by projecting the shape of the skin surface opening 3a ₁ linearly on the non-skin surface side. The body fluid has a longer distance to contact the wall surface than the through-hole 33a that is longer and inclined and is formed in a straight line, thereby realizing quick absorption. Moreover, it has the effect which prevents obstruction | occlusion of ventilation | gas_flowing by a bodily fluid by the liquid obstruction | occlusion prevention effect of the leak-proof sheet 2 and the through-hole 3a mentioned above.

Preferably the diameter _{d 1} of Hadamen opening 3a ₁ is 0.5~4.0mm for skin face opening 3a ₁ and the non-skin face opening 3a ₂ to function effectively in the present embodiment, 1-2 More preferably, it is 5 mm (see FIG. 7). Further, the inclination angle of the hole wall surface D is preferably 15 ° or more, and more preferably 17 to 45 °. In addition, in order to produce the through-hole 3a of the present embodiment, the skin surface side and the non-skin surface side of the foam material are respectively reversely pulled in the cross-sectional view, and the absorber 3 is pulled (t ₁ , t ₂ ), and above and below The through hole is formed in a state of extending in different directions. By designing the extended state, the through hole 3a having a desired angle can be formed. Further, after forming a columnar through-hole as shown in FIG. 3 in a thick foam material absorber, an oblique through-hole 3a is also formed by slicing the upper and lower surfaces of the foam material absorber at a desired angle. be able to.

In 3rd Embodiment, as shown in FIG. 8, in the cross-sectional shape of an absorber, it is curvilinear toward the non-skin contact surface from the skin contact surface. The absorbent body 3 has a two-layer structure of an upper layer foam 32 and a lower layer foam 31 in which two foam materials are bonded together at a boundary B with a hot melt adhesive, and the arrangement position in the plan view of the through-hole 3a and the excretion region W Is the same as in the first embodiment. Through hole 3a in the present embodiment, the shape in plan view of the skin surface openings 3a ₁ and the non-skin face opening 3a ₂ are the same circular shape. After this the above through hole 3a fluid is drawn into the skin surface opening 3a _1, the the present opening wall D and body fluids curved in its direction of gravity speaking modeled similarly abuts, the abutment It will be absorbed from the surface. What is important here is that, opening wall surface D to its longitudinal section line Di is longer than the projected baseline Qi obtained by projecting the shape of the skin surface openings 3a ₁ linearly in the non-skin side, tilted, poured into linear Since the body fluid has a longer distance in contact with the wall surface than the formed through-hole 33a, it is possible to prevent the through-hole from being blocked by the liquid and realize quick absorption. Moreover, it has the effect which prevents obstruction | occlusion of ventilation | gas_flowing by a bodily fluid by the liquid obstruction | occlusion prevention effect of the leak-proof sheet 2 and the through-hole 3a mentioned above.

Preferably the diameter _{d 1} of Hadamen opening 3a ₁ is 0.5~4.0mm for skin face opening 3a ₁ and the non-skin face opening 3a ₂ to function effectively in the present embodiment, 1-2 More preferably, it is 5 mm (see FIG. 9). Further, the distance to the open wall surface D in which the projected base line Qi is an arc shape is preferably 0.3 to 2.0 mm, and more preferably 0.5 to 1.5 mm. Incidentally, pressing a member curved in a thickness direction center portion of the foam material to produce a through-hole 3a of the present embodiment (t _3), opposite to the flexed absorber 3 to the direction you want to create a curved, A through hole is formed in a bent state. By designing the bending, the through-hole 3a having a desired curvature can be formed. In addition, the foam material is crushed and held to about one-tenth of the thickness before penetrating the hole, and after recovering after opening the columnar through hole, the absorber is distorted in the thickness direction when crushed, Randomly curved openings are obtained. In addition, in order to hold in the crushed state, in addition to the method of opening the hole while squeezing with the rotary die cutter itself, the absorber thinned by quenching with a hot press is reheated with hot air after penetrating the hole. Alternatively, a heat recovery method may be used.
In order to form a through-hole having a desired cross-sectional shape by continuously supplying a foam material having elastic recovery properties and thermoformability as the absorbent body 3, a rotary die cutter is used, and a cutter roll (opening roll) and a receiving roll It is effective to appropriately select the type, presence / absence of difference in peripheral speed of the roll, degree of pressing, presence / absence of roll heating, and the attachment angle between the foam material (continuous body) and the roll. For example, if a flat roll, which is a smooth metal, is used for the receiving roll and the roll is opened with a circumferential speed difference without compression between the rolls, an oblique opening can be formed. In addition, when the opening roll was heated to about 140 ° C., the foam material was attached to the opening roll side and the receiving roll (room temperature) was opened on the receiving side without any difference in peripheral speed, the front (skin surface) side was thermally contracted. It becomes a small opening. Furthermore, when the receiving roll is opened as a cotton or rubber roll while being compressed between the rolls by a roll capable of opening and closing with irregularities, a curved opening can be formed. Further, if a peripheral speed difference is given, a curved oblique hole can be formed.

  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 through holes 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. In addition, 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 manufacturing method, and the dimensions of the product are not particularly limited.

  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%. 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.

  In the present invention, the absorbent body 3 is made of a foam material. The foam material is typically a resin molded body (foam) produced by foaming the inside, and has an open cell structure even in a closed cell structure. However, a foam material having a hydrophilic and open cell structure is preferable 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. Regarding various conditions in the production method of the foam material, reference can be made to the matters described in JP-T-8-504474.

1 the topsheet 2 barrier sheet 3 absorber 3a through holes _3a 1, 3a ₂ opening 33a columnar through hole 10 a sanitary napkin

Claims (3)

Absorbent article having a liquid-permeable surface sheet disposed on the skin contact surface side, a moisture-permeable leak-proof sheet disposed on the non-skin contact surface side, and an absorbent body interposed between the both sheets The absorber has a plurality of holes penetrating from the skin contact surface toward the non-skin contact surface in the excretion region, and is formed by the through-hole wall surface, the skin contact surface, and the non-skin contact surface. The cross-sectional shape is such that the line formed by the wall surface is inclined with respect to the normal of the skin contact surface, and the wall area (Aa) of the through hole is larger than the wall area (Ab) of the virtual columnar through hole. The cross-sectional shape of the through-hole is a parallelogram shape inclined at least 15 degrees from the skin contact surface to the non-skin contact surface, or a parallel curve shape from the skin contact surface to the non-skin contact surface. An absorbent article, wherein the absorbent body is made of a hydrophilic foam material and has continuous micropores in a dry state . The absorbent article according to claim 1, wherein the absorbent article is a sanitary napkin in which the through hole is disposed only in the excretion region. The absorbent article according to claim 1 or 2, wherein an opening diameter of the through hole is larger than an average distance between skeletons of the foam material in the absorbent body.

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