JP4573705B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article with less menstrual blood (blood) return.

In absorbent articles such as sanitary napkins for the purpose of menstrual blood and blood absorption, menstrual blood absorbed by the absorbent body from the skin contact surface returns to the skin contact surface by pressurization, It may be sticky.
As a method for reducing stickiness, the surface sheet forming the skin contact surface is provided with irregularities to reduce the contact area with the skin, or a bulky nonwoven fabric is used for the surface sheet. The performance required for absorbent articles is increasing year by year, and there is a possibility that the demands in recent years and in the near future cannot be sufficiently met only by the contrivance of the surface sheet.

  Patent Document 1 describes polyester-based ultrafine fibers useful as a web-like material, and Patent Document 1 describes ultrafine fibers produced without using an antimony trioxide-based catalyst. Further, it is described that when a web made of the ultrafine fibers is used for a blood separation filter, a washing step is unnecessary and it is advantageous in terms of cost. In Patent Document 1, a sanitary product is described as one of many listed uses of webs made of ultrafine fibers. However, there is no description about using a web made of ultrafine fibers for a sanitary product in a mode having blood separation ability.

  Patent Document 2 describes that a polymer foam material capable of absorbing blood and blood-based fluid is used as an absorbent member for a menstrual pad. However, the document 2 does not describe any blood separation ability.

JP 2001-348728 A Japanese National Patent Publication No. 10-512168

  An object of the present invention is to provide an absorbent article that can significantly reduce the amount of returned menstrual blood (blood).

  The present invention achieves the above object by providing an absorbent article including a blood separator capable of separating blood into blood cells and plasma.

  According to the absorbent article of the present invention, the liquid return amount of menstrual blood (blood) can be greatly reduced.

The present invention will be described below based on preferred embodiments with reference to the drawings.
As shown in FIG. 1, a sanitary napkin 1 according to an embodiment of the present invention includes a liquid-permeable top sheet 2, a liquid-impermeable or water-repellent back sheet 3, and the two sheets 2, 3. The absorbent core 4 is provided, and the absorbent core 4 is composed of a blood separator that can be separated into blood cells and plasma.

  The blood separator used in the present invention has a function of separating blood into blood cells and plasma (hereinafter also referred to as blood separating ability). Since most of the blood cells in the blood are red blood cells, separation of blood cells and plasma when blood is introduced from the skin contact surface side of the absorbent article causes the liquid component of blood to pass through the blood separator. It appears that the range in which the color of red blood cells (red) expands in the blood separator is narrower than the range (three-dimensional range). Separation of blood cells and plasma does not require that blood cells and plasma be completely divided in two.

As the blood separator, those having a ratio of pores having a pore diameter of 6 μm or less in the pore diameter distribution measured by ASTM F316-86 of 20 to 90% can be preferably used.
Red blood cells have a disk shape with a depressed central part, and have a diameter of 6 μm and a thickness of about 2 μm. When the proportion of pores having a pore diameter of 6 μm or less is at least a certain level, red blood cells of such a form are efficiently trapped in the pores and good blood separation ability is expressed. Further, the proportion of pores having a pore diameter of 6 μm or less is not 100%, that is, the presence of pores having a pore diameter of more than 6 μm has good blood separation ability not only on the surface of the blood separator but also inside. Since it is exhibited, it is preferable.
The proportion of pores having a pore diameter of 6 μm or less is more preferably 20 to 90%, and further preferably 30 to 80%.

The pore size distribution according to ASTM F316-86 can be measured using, for example, a porous material CPM-1200-AEXL-ESA manufactured by Porous Materials. Specifically, a circular sample having a diameter of about 10 to 15 mm is prepared, immersed in a liquid having a known surface tension, and left under a reduced pressure of 20 mmHg or less for 15 minutes or more (usually about 20 to 30 minutes). The sample taken out was used as a wet sample.
As shown in FIG. 2, the wet sample S was set in the holder 10 by being sandwiched between two acrylic resin disks 11 and 12 having a 3.3 mm diameter circular hole at the center. By the screwing of the lid 13, the cylindrical member 14 presses the disk 11 and the sample S is stably fixed. The black circles in FIG. 2 are rubber packings that prevent gas from flowing through the gaps in which the rubber packings are arranged.

The holder 10 to which the wet sample S is fixed as described above is set in the palm porometer, and the gas pressure on the bottom surface side of the holder 10 is set at a constant speed (1.4 × 10 ⁵ Pa / min). Raised. The changes in the pressure of the gas applied to the sample S and the flow rate of the gas flowing out of the holder 10 were recorded as shown in FIG.

As long as the pressure of the gas applied to the sample S is low, as shown between the points a and b in FIG. 3, the flow rate is not shown at all. Gas outflow occurs. The pressure at which gas outflow is first observed (pressure at point b in FIG. 3) is the bubble point, and the maximum pore diameter of the sample is calculated from this pressure. When the pressure increase is further continued, the gas flow rate increases while drawing a curve corresponding to the pore size distribution (the portion between points bc in FIG. 3). The amount of increase in the flow rate is proportional to each other, and the relationship line between the pressure and the gas flow rate is linear (the portion between cf in FIG. 3). The minimum pore diameter of the sample is calculated from the pressure e at the point where the relation line between the pressure and the gas flow rate changes from a curved line to a straight line (point c in FIG. 3).
When the relationship line between the pressure and the gas flow rate is linear, it is considered that all the liquid in the sample pores has been blown off and the sample has become dry, and this time the pressure applied to the sample S is constant. Decrease at the speed of. Even in the pressure decreasing process, the change in the pressure applied to the sample S and the flow rate of the gas flowing out of the holder 10 is recorded.

In a dry sample, since the change amount of the flow rate is simply proportional to the change amount of the pressure, the relationship line between the pressure and the gas flow rate is a straight line like a line segment df.
The flow rate ratio Q corresponding to the specified pressure range (between PL and PH) of the sample is calculated from the flow graph (line segment df) of the dry sample and the flow graph (curve abc) of the wet sample. Calculated by the formula.
Q (%) = [(WH / DH) − (WL / DL)] × 100 (%)
Here, (WH / DH) is (flow rate of air passing through holes larger than the hole diameter corresponding to pressure PH / flow rate of air passing through all holes at pressure PH). The ratio of the total number of holes larger than the corresponding hole diameter to the total number of holes is calculated. On the other hand, (WL / DL) is (the flow rate of air passing through a hole larger than the hole diameter corresponding to the pressure PL / the flow rate of air passing through all holes at the pressure PL). The ratio of the total number of holes larger than the total hole diameter to the total number of holes is calculated. And from (WH / DH)-(WL / DL) which is a difference between the two, the ratio of the number of pore diameters corresponding to the pressures PL to PH to the total number of holes is calculated.

If this is divided in small increments within the pressure range from point b to point e, Q corresponding to each minute range can be calculated, and the pore diameter distribution can be derived.
In Examples described later, the pressure between the pressure indicating the maximum pore diameter (the pressure at point b in FIG. 3) and the pressure indicating the minimum pore diameter (the pressure at point e in FIG. 3) corresponds to the pore diameter of 2 μm. In order to make it easy to understand the class value of the histogram, the division boundaries were set so that the pore diameter was an integer (that is, 2 μm, 4, 6, 8,...). The pressure range lower than point b and the pressure range higher than point e fall within the class value, but the value of Q does not change.
Moreover, Galwick (16 mN / m) of Porous Materials was used as the liquid having a known surface tension, and the gas was air dried by cooling compression (using DPKH-37 manufactured by Meiji Machinery Co., Ltd.).

FIG. 4A is a graph showing the pore size distribution measured in accordance with ASTM F316-86. The horizontal axis is the pore size (μm), and the vertical axis is the flow rate of air passing through the pore having the pore size. It is the ratio of the number of pores obtained from In the examples described later, the above-mentioned palm porometer has histograms (see FIG. 4 (a)) and FIG. 4 (b) showing the proportion of pores included in the range for each pore diameter of 2 μm. Graphs were prepared, and the proportion of pores of 6 μm or less was obtained from them.
In FIG. 4B, the horizontal axis is the pore diameter (μm) and the vertical axis is the proportion of pores equal to or smaller than the pore diameter, which is created based on the graph showing the pore diameter distribution as shown in FIG. It is a graph. In the example shown in FIG. 4B, it can be seen that the numerical value on the vertical axis corresponding to the pore diameter of 6 μm is about 40%, and the proportion of pores having a pore diameter of 6 μm or less is about 40%.

In the sanitary napkin 1 of this embodiment, a blood separator made of a fiber assembly is used.
For example, a fiber assembly in which the proportion of pores having a pore diameter of 6 μm or less is 20% or more is a method of subjecting a fiber assembly manufactured by a melt blown method or a fiber assembly manufactured using split-type composite fibers to a calendar process Can be obtained. The fiber assembly in this specification is a concept including a non-woven fabric. Spinning by the melt blown method, splitting the constituent components of the split-type composite fiber, fibers having a very small fiber diameter can be obtained, and further, by applying a calender treatment to the fiber assembly composed of such fibers, A fiber assembly suitably used as a blood separator is obtained. A blood separator can also be obtained by subjecting a fiber assembly made of ultrafine fibers (fibers having an average fiber diameter of 1 to 10 μm) produced by other methods to calendar treatment.

  The calendar process described above is a process for densifying the fiber assembly by applying heat and pressure to the fiber assembly with a calendar roll. The number and arrangement of the calender rolls are not particularly limited. Three rolls in series or inclined type, four rolls in series type, inverted L type, Z type, inclined Z type, five rolls Z type And L-type.

The calendar process is preferably performed under the following conditions.
The temperature in the calendar treatment is preferably below the softening point of the constituent fibers. When calendering is performed above the softening point, the fibers adhere to each other and the blood diffusion path is closed. The pressure in the calendering process is not particularly limited as long as the ratio of the pores having a pore diameter of 6 μm or less in the fiber aggregate is 20 to 90% in the pore diameter distribution measured by ASTM F316-86.

  The split-type composite fiber is composed of, for example, two or more types of resins different from each other, and each resin is continuously arranged in the longitudinal direction of the fiber and alternately arranged in the circumferential direction of the fiber. In addition, a resin that can be separated and separated from each other by a thermal action and / or a mechanical action can be used. As the split-type composite fiber, fibers that can be divided into 4 to 32 can be used. In the split type composite fiber, the constituent resin may be already separated at the stage before the calendar treatment, or the constituent resin may be separated by the calendar treatment.

The fiber assembly as the blood separator preferably has an average fiber diameter of 3 to 30 μm of the constituent fibers. When the thickness exceeds 3 μm, a certain degree of strength is obtained in the fiber itself, and sufficient strength is obtained in the blood separator. By setting the thickness to 30 μm or less, for example, when the absorbent article is a sanitary napkin, it is possible to prevent the wearer from feeling uncomfortable due to the rigidity of the blood separator. From these viewpoints, the average fiber diameter is more preferably 5 to 15 μm.
The average fiber diameter is measured as follows.
The fiber assembly is frozen with liquid nitrogen and cut with a sharp blade. The cut surface was photographed with a scanning electron microscope at a magnification of 800 to 2000 times, and the fiber diameter was measured by comparing any 10 points of the fiber cross section with the scale gauge shown in the photograph. take.

  The fiber assembly as the blood separator may be any of synthetic fibers, regenerated fibers (semi-synthetic fibers), and natural fibers, but may be synthetic fibers and / or regenerated fibers (semi-synthetic fibers). preferable. In particular, fibers made of one or more thermoplastic polymers selected from polyesters, polyamides, polyolefins, and ethylene-vinyl alcohol copolymers are preferable from the viewpoint of fiber strength, cost, and processability.

The fiber aggregate as the blood separator is preferably a fiber aggregate mainly composed of hydrophilic fibers since blood separation ability is well expressed. That is, plasma in blood diffuses well, and separation of blood cells and plasma is good. Moreover, since the liquid retention ability of a fiber assembly improves, it is preferable also from a viewpoint of using a blood separator as an absorptive core for the purpose of liquid retention like the napkin 1 of this embodiment.
The hydrophilic fiber includes a synthetic fiber hydrophilized with a hydrophilizing agent and a regenerated fiber that is originally hydrophilic even if it is not treated with a hydrophilization treatment. The content of the hydrophilic fiber in the fiber assembly is preferably more than 50% to 100% by mass, particularly preferably 70 to 100% by mass. Two or more hydrophilic fibers may be mixed.

  As the hydrophilic fiber, a synthetic fiber hydrophilized with a hydrophilic treatment agent is preferable. As the hydrophilic treatment agent, a surface-attached treatment agent to be attached to the fiber surface, a kneading type used by kneading into a raw material resin. Either a treatment agent or a surface-fixing treatment agent that fixes a part of the treatment agent attached to the fiber surface to the fiber by heat treatment or the like may be used. Among these, from the viewpoint of cost and workability, a surface-attached type or a surface-fixed type processing agent is preferable. Hydrophilization with a surface-attached or surface-fixed treatment agent is, for example, an aqueous solution of a surfactant (anionic surfactant, nonionic surfactant, etc.) or a hydrophilic polymer (polyvinyl alcohol, acrylamide, polyacrylic acid). And a method in which the fiber aggregate is dipped in an aqueous solution of an alkali metal salt thereof, polyvinylpyrrolidone, etc.) and dried to make the fiber surface hydrophilic.

  The fiber aggregate mainly composed of hydrophilic fibers preferably includes hydrophobic fibers as well as hydrophilic fibers. The coexistence of hydrophobic fibers improves the liquid diffusibility, and can effectively utilize a wide range of blood separators. Therefore, the liquid return amount can be further reduced. However, the content of the hydrophobic fiber in the fiber assembly as the blood separator is preferably 30% by mass or less, particularly preferably 20% by mass or less. As the hydrophobic fiber, it is possible to use a synthetic fiber made of a thermoplastic polymer such as polyester, polyamide, polyolefin, etc., which has not been hydrophilized. Two or more kinds of hydrophobic fibers can be mixed and used.

  The fiber aggregate as a blood separator has a thickness T (see FIG. 1) of not less than 0.3 mm under a pressure of 49 Pa, from the viewpoint of expressing good blood separation ability and resulting liquid return reduction effect. Is more preferable, and more preferably 0.5 mm or more. The upper limit of the thickness T can be appropriately determined in relation to the absorption capacity and the like required for the absorbent core, and is not particularly limited, but is 5.0 mm or less from the viewpoint of preventing a sense of incongruity when the absorbent article is mounted. It is preferable that

  The thickness T is measured by the following method. First, the fiber assembly is cut into a size of 50 mm × 50 mm to obtain a measurement piece. A 12.5 g plate larger than the measurement piece is placed on the measurement table. The position of the upper surface of the plate in this state is set as a measurement reference point A. Next, the plate is removed, the measurement piece is placed on the measurement table, and the plate is placed again thereon. Let B be the position of the front surface of the plate in this state. The thickness of the fiber assembly is determined from the difference between A and B. A laser displacement meter (CCD Laser Displacement Sensor LK-080 manufactured by Keyence Corporation) is used as a measuring instrument, but a dial gauge type thickness meter can also be used. In this case, the measurement pressure is adjusted to 49 Pa.

Further, the basis weight of the fiber assembly as the blood separator is preferably 10 to 300 g / m ^{2 and} particularly preferably 30 to 200 g / m ² from the viewpoint of strength and flexibility.

According to the sanitary napkin 1 of the present embodiment, as shown in FIG. 5A, the blood (menstrual blood) 7 supplied to the skin contact surface side (surface sheet side) of the napkin is a surface sheet (illustrated). And is absorbed by the blood separator constituting the absorbent core 4 as shown in FIG. The blood (menstrual blood) 7 absorbed in the blood separator is filtered in the blood separator and separated into blood cells 71 and plasma (liquid component) 72 as shown in FIG. 5 (c). While spreading over a wide range in the blood separator, the blood cell 71 only spreads over a relatively narrow range.
When blood (menstrual blood) is separated into blood cells and plasma in the blood separator, the absorbed blood returns to the skin contact surface (surface of the surface sheet) of the sanitary napkin, that is, liquid. Return is greatly reduced.

  The reason why the liquid return is reduced is that, as shown in FIG. 5 (d), the portion where the ratio of blood cells to the plasma is remarkably increased due to the blood being filtered and separated by the blood separator. It seems that a high-viscosity layer is formed in the vicinity of the surface on the surface sheet side, and this high-viscosity layer prevents the return of plasma.

  In addition, it is preferable that the blood separator does not contain a superabsorbent polymer, because the absorbent article becomes soft as a whole, and the feeling of fitting and fit are improved.

  The material for forming each part of the sanitary napkin 1 will be described. As the top sheet 2 and the back sheet 3, various materials conventionally used for this type of absorbent article can be used without particular limitation. For example, as the surface sheet, nonwoven fabrics produced by various manufacturing methods, those obtained by forming holes in a resin film, laminates of these, and the like can be used. As the back sheet, a thermoplastic resin film with or without moisture permeability, a water-repellent nonwoven fabric, or a laminate thereof can be used.

  Next, a sanitary napkin as another embodiment of the present invention will be described with reference to FIGS. In the following description, differences from the sanitary napkin described above will be mainly described, and the same points will be denoted by the same reference numerals and description thereof will be omitted. The points described above with respect to the sanitary napkin described above are appropriately applied to points not specifically mentioned.

The sanitary napkin 1A shown in FIG. 6 uses a blood separator 5 made of a porous resin film. As the blood separator made of a porous resin film, those having a ratio of pores having a pore diameter of 6 μm or less of 20 to 90% in the pore diameter distribution measured by ASTM F316-86 can be preferably used.
A resin film that satisfies such conditions is, for example, a mixture of a thermoplastic resin such as polypropylene or polyethylene mixed with a filler such as calcium carbonate, extruded into a sheet (film), and stretched to form a fine film. It can be manufactured by a method of opening a fine pore and applying a calendar process. In this case, the amount of calcium carbonate to be mixed is preferably 40 to 80% by mass. If it is less than 40% by mass, fine pores are not opened even if it is stretched, and if it exceeds 80% by mass, the physical properties of the film deteriorate. More preferably, it is 50-70 mass%. The average particle diameter of calcium carbonate is preferably 0.1 to 10 μm. If it is less than 0.1 μm, the calcium carbonate particles cause secondary agglomeration and cannot be uniformly mixed with the thermoplastic resin, and if it is 10 μm or more, large pores are opened when the film is stretched. However, it becomes difficult to make a fine structure of 20% or more. Preferably it is 0.5-5 micrometers. The draw ratio is preferably 1.5 to 5 times. If it is less than 1.5 times, pores are not opened in the film, and if it exceeds 5 times, the film is broken during stretching. More preferably, it is 1.7 to 3 times. The stretching may be uniaxial or biaxial, but biaxial stretching is preferred from the viewpoint of film strength.

When a porous resin film is used as the blood separator, it is difficult to give the liquid retaining ability itself. Therefore, in the sanitary napkin 1A, the non-skin contact surface of the porous resin film 5 is used. On the side, the absorbent core 4 </ b> A having a conventionally used configuration is arranged.
As the absorbent core 4A, various absorbent cores conventionally used for this type of article can be used. For example, a fiber aggregate mainly composed of pulp fibers or a superabsorbent polymer held in the fiber aggregate. The absorptive core which becomes.

In the sanitary napkin 1B shown in FIG. 7, an intermediate sheet 6 is disposed between the top sheet 2 and the absorbent core 4 made of a blood separator.
Since the blood separator made of a fiber assembly has a dense structure, the conventional general absorption made of a piled fiber of pulp fibers or the like in that the blood supplied on the top sheet 2 is quickly absorbed. Although the absorption rate tends to be inferior to that of the conductive core, the absorption rate can be improved by arranging the intermediate sheet 6.

The intermediate sheet 6 must be capable of quickly transferring the blood supplied on the top sheet 2 to the absorbent core 4. As the intermediate sheet 6, a nonwoven fabric having such functions or physical properties can be used without particular limitation. The non-woven fabric used as the intermediate sheet 6 preferably has a fineness of constituent fibers of 1 to 10 dtex, particularly 2 to 7 dtex, and a thickness (under a pressure of 49 Pa) of 0.3 to 1.0 mm, particularly 0.5 to 0. is preferably .8Mm, basis weight of 10 to 50 g / m ^2, it is particularly preferably 20 to 40 g / m ^2.
The nonwoven fabric used as the intermediate sheet 6 can be manufactured by a spun bond method, a melt blown method, an air through method, or the like, but is preferably manufactured by an air through method. The intermediate sheet 6 has a ratio of pores having a pore diameter of 6 μm or less in a pore diameter distribution measured by ASTM F316-86 of 5% or less.

The present invention is not limited to the above embodiment, and can be modified as appropriate.
For example, a blood separator made of a fiber assembly can be used as an absorbent core by laminating a large number of sheets. In addition, a single-layer or multi-layer blood separator can also be used as an absorbent core in combination with conventional pulp fiber piles. In addition, a blood separator made of a porous resin film and a blood separator made of a fiber assembly can be used in combination.

  In addition, the blood separator may be disposed over the entire region of the sanitary napkin where the liquid can be absorbed, or may be disposed only in a portion facing the menstrual discharge portion of the wearer. Moreover, it can also arrange | position only to the site | part biased to either the front or back of a napkin, the site | part biased to either the left or right.

Further, the blood separator composed of the fiber assembly may not be covered with tissue paper or a water-permeable nonwoven fabric, or may be covered with such a material. The absorbent article may be one in which a blood separator made of a fiber assembly is disposed between a liquid-permeable top sheet and a liquid-permeable back sheet.
In addition, the absorbent article in the present invention may be a bandage, a wound dressing, a surgical drape, etc. in addition to a sanitary napkin.

[Example 1]
Using a polypropylene (PP) resin as a raw material, a nonwoven fabric having an average fiber diameter of 10 μm and a basis weight of 30 g / m ² was obtained by a melt blown method. This was calendered under conditions of a temperature of 40 ° C. and a linear pressure of 250 kgf / cm, and then immersed in an aqueous solution of 0.05% surfactant (Myoru 10 manufactured by Kao Corporation) and dried naturally to give a sample nonwoven fabric. Obtained.
When the pore size distribution of the obtained sample nonwoven fabric was measured by the pore size distribution measuring method described above, the proportion of pores having a pore size of 6 μm or less was 20%. The obtained sample nonwoven fabric was cut into a dimension of 15 cm in length and 6 cm in width, and this was used as a blood separator to obtain a top sheet and a back sheet taken from a commercially available sanitary napkin (manufactured by Kao Corporation, Laurie Sarasara cushion daytime) A sanitary napkin was produced.

[Example 2]
The same sample nonwoven fabric as in Example 1 was used as a blood separator, and a nonwoven fabric having a basis weight of 40 g / m ² manufactured by the air-through method was used as an intermediate sheet. These were placed between the top sheet and the back sheet on the top sheet side. A sanitary napkin was produced in the same manner as in Example 1 except that the intermediate sheet was positioned and the blood separator was positioned on the back sheet side.

Example 3
A web having a basis weight of 60 g / m ² was manufactured using 16-divided fibers made of polypropylene (PP) resin and polyethylene (PE) resin, and the fibers were entangled by a hydroentanglement method to obtain a nonwoven fabric. This was calendered at a temperature of 40 ° C. and a linear pressure of 250 kgf / cm, then immersed in an aqueous solution of 0.05% surfactant (Myoru 10 manufactured by Kao Corporation) and dried naturally to obtain a sample nonwoven fabric. It was.
When the pore diameter distribution of the obtained sample nonwoven fabric was measured by the above-described pore diameter distribution measuring method, the proportion of pores having a pore diameter of 6 μm or less was 40%. A sanitary napkin was produced in the same manner as in Example 1 except that the obtained sample nonwoven fabric was used as a blood separator.

[Comparative Example 1]
Using a polypropylene (PP) resin as a raw material, a nonwoven fabric having a basis weight of 60 g / m ² is prepared by a melt blown method, and this is dipped in an aqueous solution of 0.05% surfactant (Maidoll 10 manufactured by Kao Corporation). The sample nonwoven fabric was obtained by drying.
When the pore size distribution of the obtained sample nonwoven fabric was measured by the pore size distribution measuring method described above, the proportion of pores having a pore size of 6 μm or less was 14%. A sanitary napkin was produced in the same manner as in Example 1 except that the obtained sample nonwoven fabric was used instead of the sample nonwoven fabric used in Example 1.

[Comparative Example 2]
A commercially available spunbonded nonwoven fabric (Shintex PS-112 manufactured by Mitsui Chemicals, Inc.) was immersed in an aqueous solution of 0.05% surfactant (Mydol 10 manufactured by Kao Corporation) and dried naturally to obtain a sample nonwoven fabric. When the pore size distribution of the obtained sample nonwoven fabric was measured by the above-described pore size distribution measurement method, the proportion of pores having a pore size of 6 μm or less was 10%. A sanitary napkin was produced in the same manner as in Example 1 except that the obtained sample nonwoven fabric was used instead of the sample nonwoven fabric used in Example 1.

[Evaluation of difficulty in returning liquid]
About each sanitary napkin manufactured by the Example and the comparative example, the blood return property test shown below was done and the difficulty of liquid return was evaluated. The results are shown in Table 1.
[Liquid return test]
Place an acrylic plate with a 10 mm diameter hole on the sanitary napkin so that the hole is in the center of the top sheet, and apply a pressure of 3.5 × 10 ² Pa on the sanitary napkin. I put a smell on it. In this state, 3 g of equine defibrinated blood was injected from the hole. One minute after injection, the acrylic plate is removed, 10 sheets of tissue paper 10 cm long and 6 cm wide are placed on the top sheet, and a weight is applied so that the pressure becomes 6.6 × 10 ³ Pa. Placed and pressurized for 2 minutes. After pressurizing for 2 minutes, the mass of blood absorbed in the tissue paper was measured, and the mass was taken as the blood return amount.

  As can be seen from Table 1, in the sanitary napkin of the example, the blood return amount is greatly reduced compared to the sanitary napkin of the comparative example.

FIG. 1 is a cross-sectional view showing a cross section in the thickness direction of a sanitary napkin according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an instrument used for measuring the pore size distribution and a method for fixing the sample. FIG. 3 is a graph showing changes in pressure and flow rate when measuring the pore size distribution. FIG. 4 (a) is a graph showing the pore size distribution measured by ASTM F316-86, and FIG. 4 (b) is a pore size created based on the measured pore size distribution and pores smaller than the pore size. It is a graph which shows the relationship with the ratio. FIG. 5 is a diagram showing the action of the blood separator in the present invention. FIG. 6 is a cross-sectional view showing a cross section in the thickness direction of a sanitary napkin according to another embodiment of the present invention. FIG. 7 is a cross-sectional view showing a cross section in the thickness direction of a sanitary napkin according to still another embodiment of the present invention.

Explanation of symbols

1, 1A, 1B Sanitary napkin (absorbent article)
2 Top sheet 3 Back sheet 4 Absorbent core made of blood separator 5 Blood separator made of porous resin film 6 Intermediate sheet 7 Menstrual blood (blood)

Claims (4)

An absorbent article comprising a blood separator capable of separating blood into blood cells and plasma ,
The blood separator is composed of a non-woven fabric obtained by calendering a fiber assembly produced using a split composite fiber, and has a pore diameter of 6 μm or less in a pore diameter distribution measured by ASTM F316-86. An absorbent article having a ratio of 20 to 90% .   The absorbent article according to claim 1, wherein the blood separator is composed of a fiber assembly mainly composed of hydrophilic fibers. The blood separating member is disposed in the non-skin contact surface side of the liquid-permeable topsheet, between the top sheet and the blood separator, claim intermediate sheet is disposed one or two The absorbent article as described. It is a manufacturing method of the absorptive article according to claim 1,
The manufacturing method of an absorbent article including the process of obtaining the nonwoven fabric used as the said blood separation body by giving a calendar process to the fiber assembly manufactured using the split type composite fiber .

Images