JP2011072815A - Filter for blood processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter for blood processing capable of sufficiently reducing the loss of a material caused in a manufacturing process, and achieving a higher blood recovery than conventional filters. <P>SOLUTION: The filter for blood processing includes: a sheet-like filter material, a container that is made of a flexible material and houses a filter material; a joint part which is formed over the whole circumference of the peripheral part of the filter material, and defines a blood processing domain by joining the filter material and the container in the thickness direction of the filter; an inlet provided in a surface of the container; and an outlet provided in another surface of the container. The shape of the joint part is a hexagon, and the shape of the filter material is also a hexagon. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a blood processing filter for removing undesirable components such as aggregates and leukocytes from blood. This filter has a filter medium and a flexible container that accommodates the filter medium, and is mainly used when blood is filtered by gravity. The “blood” in the present invention includes not only whole blood but also blood products such as red blood cell preparations, platelet preparations and plasma preparations.

  In the field of blood transfusion, so-called leukocyte-removed blood transfusion, in which a blood product is transfused after removing contaminating leukocytes contained in the blood product, has become widespread. This includes relatively minor side effects such as headache, nausea, chills, and non-hemolytic fever reactions associated with blood transfusions, severe alloantigen sensitization, viral infections, post-transfusion GVHD, and other serious effects on recipients. This is because it has been clarified that such a side effect is mainly caused by leukocytes mixed in the blood product. There are several methods for removing leukocytes. Among them, the filter method is currently popular because it has advantages such as excellent leukocyte removal performance, simple operation, and low cost.

  Conventionally, processing of blood products and the like by a filter method, that is, a leukocyte removal filter, has often been performed at the bedside when performing a blood transfusion operation. However, in recent years, filtration is generally performed at a blood center in order to thoroughly control the quality of blood products. When filtering blood at a blood center using a filter, place a bag containing a blood product that may contain white blood cells, etc. 20 to 100 cm higher than the filter, and filter the blood product by the action of gravity. In general, the bag is collected in the downstream bag (see FIG. 1).

  By the way, the filter of the said use has the filter material which consists of a nonwoven fabric and a porous body, and the container which accommodates this. There are two types of filters depending on the nature of the container. On the other hand, the container is made of a hard material such as polycarbonate. On the other hand, the container is made of a material excellent in flexibility (see Patent Documents 1 to 4). The flexible container is made of the same or similar material as that used in the blood collection / separation set bag. In the past, rigid container filters have been widely used, but since the development of flexible container filters, this filter has become widely used.

European Patent No. 0526678 JP-A-11-216179 : JP-A-7-267871 International Publication No. 95/17236

  In recent years, the declining birthrate and aging population are progressing in developed countries, and the blood donable population is decreasing. As the population that can be collected decreases, the number of blood samples decreases, and there is a concern that the shortage of blood necessary for blood transfusion will become a serious problem.

  Under such circumstances, the blood treatment by the filter method is required to further reduce the blood that remains in the filter and is not recovered and is discarded as it is. In the conventional filter, blood tends to remain inside after processing, and there is room for improvement in this regard. It may be possible to realize this by adopting a complicated mechanism if only the reduction of blood residue is solved. However, since filters in the field are generally disposable, it is important in terms of manufacturing efficiency and material cost that they have a relatively simple configuration suitable for mass production.

  The present invention has been made in view of the above circumstances, and can provide a blood processing filter that can sufficiently reduce the loss of material that occurs in the manufacturing process and that can realize a higher blood recovery rate than conventional filters. The purpose is to provide.

  The filter for blood treatment according to the present invention is formed over the entire circumference of the peripheral edge of the filter medium, the filter medium in the form of a sheet-shaped filter medium, a container made of a flexible material, and containing the filter medium. Are joined in the thickness direction of the filter to define a blood treatment region, an inlet provided on one side of the container, and an outlet provided on the other side of the container. The shape of the first joint is a hexagon, and the shape of the filter medium is also a hexagon.

  Conventional filters generally have a rectangular shape (square or rectangular shape) of the flexible container and the filtering material (see FIGS. 7 to 9). The conventional filter 50 shown in FIGS. 7 and 8 has a joint portion 55 that integrally joins the filter medium 51 and the flexible container 53 in the thickness direction. The joining portion 55 is formed along the peripheral edge of the filter material 51, and the shapes of the filter material 51 and the joining portion 55 are both rectangular.

  On the other hand, in the present invention, it is one of the important points that the shapes of the filter medium and the first joint are hexagonal (see FIG. 2). According to the investigation by the present inventors, in order to increase the blood recovery rate, it is effective that the shape of the blood treatment region is not a rectangle, but a circle, an ellipse, or a polygon greater than a hexagon. On the other hand, the amount of discarded filter material generated during the manufacture of the filter and the time required for cutting increase in the order of rectangle, hexagon, ellipse, and circle. That is, the loss of material and time in the manufacturing process is the smallest when the shape of the filter medium is rectangular.

  As described above, a trade-off relationship is recognized between the improvement of the blood recovery rate and the efficiency of the filtering material processing process. The present inventors considered the structure of the filter in consideration of this relationship. As a result, it has been found that when the shape of the filter medium and the first joint is hexagonal, both the blood recovery rate and the efficiency of the filter medium processing process can be achieved to a sufficiently high level.

  In the filter of the present invention, since the shape of the filter medium is hexagonal, it is possible to minimize the discard amount of the filter medium fragments in the process of cutting the filter medium material to obtain the filter medium. Among hexagons, when the filter of the present invention is arranged in the vertical direction so that the inlet of the filter is located above and the outlet is located below, a rectangular region between two sides extending parallel to each other in the vertical direction. And a hexagonal shape composed of an upper isosceles triangular area adjacent above the rectangular area and a lower isosceles triangular area adjacent below the rectangular area is preferable (see FIGS. 2 and 5).

  In order to further improve the blood recovery rate, when the filter of the present invention is arranged in the vertical direction so that the inlet is located above and the outlet is located below, the area of the blood treatment region below the outlet is It is preferably 10% or more and less than 26% of the total area.

The filter of the present invention preferably further includes a second joint that joins the peripheral edge of the container in the thickness direction of the filter in order to protect the filter medium from the external environment more reliably.

  According to the filter of the present invention, a higher blood recovery rate than that of the conventional filter can be realized. This filter has a feature that the loss of material generated in the manufacturing process is sufficiently small.

FIG. 1 is a schematic diagram showing a configuration of a blood processing apparatus including a filter according to the present invention. FIG. 2 is a plan view showing a preferred embodiment of the filter according to the present invention. FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a diagram showing a cutting line for the filter material. FIG. 5 is a plan view showing another embodiment of the filter according to the present invention. FIG. 6 is a plan view showing another embodiment of the filter according to the present invention. FIG. 7 is a plan view showing an example of a conventional filter. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is a plan view showing another example of a conventional filter.

[Blood processing filter]
The filter 10 according to the present embodiment is for removing microaggregates and white blood cells that cause side effects from blood for transfusion, and has a rectangular flat shape. As shown in FIG. 1, blood is filtered by arranging a bag 21 containing blood, a filter 10 and a blood collection bag 22 so that they are arranged in this order from the top to the bottom. The filter 10 is connected to the backs 21 and 22 by tubes 25 and 26, and a Robert clamp 27 and a chamber 28 are disposed in the middle of the tube 25.

As shown in FIG. 2, the filter 10 includes a sheet-like filter medium 1, a flexible container 3 that accommodates the sheet-like filter medium 1, an inner joint portion (first joint portion) 5 that defines the blood treatment region R, and And an outer joint (second joint) 6.

  An inlet 7 is provided on one side F1 of the container 3, and an outlet 8 is provided on the other side F2. The inlet 7 and the outlet 8 are provided with tube connection ports 7a and 8a, respectively. In use, the filter 10 is arranged in the vertical direction so that the blood flowing in from the inlet 7 flows vertically downward and reaches the outlet 8 so that the inlet 7 is located above and the outlet 8 is located below. The Hereinafter, the configuration of the filter 10 will be described, but the positional relationship between the elements of the filter 10 will be described based on the arrangement when the filter 10 is used.

  In the filter 10, the shape of the filter medium 1 is a regular hexagon, and the shape of the inner joint portion 5 is also a regular hexagon. The inner joint portion 5 integrally joins the filter medium 1 and the container 3 to define a blood treatment region R (hereinafter referred to as “region R”) of the filter 10.

  The region R is a regular hexagon like the inner joint 5. As shown in FIG. 2, the region R is formed such that sides S1 and S2 extending in the vertical direction are arranged on the left and right, and vertices C1 and C2 are arranged on the upper and lower sides, respectively. An inlet port 7a is formed immediately below the upper vertex C1 of the region R, and an outlet port 8a is formed immediately above the lower vertex C2. By forming the inlet port 7a and the outlet port 8a at such positions, the distance between the inlet 7 and the outlet 8 can be increased, and a sufficient distance for blood to flow through the filter medium 1 is secured. it can.

  In order to sufficiently reduce the amount of blood remaining in the filter 10 after processing, the area of the region R below the outlet 8 is preferably less than 26% of the entire region R, and less than 23%. Is more preferable. The region R below the outlet 8 is a region indicated by hatching in FIG. The lower limit of the area ratio below the outlet 8 is preferably 10%, more preferably 12%, and even more preferably 15% from the viewpoint of ease of installation of the outlet 8. If the distance from the outlet of the filter to the lowest point of the blood treatment region is the same, the area of the region below the outlet is the smallest in the regular hexagon, and increases in the order of a circle and a rectangle. Therefore, a filter having a regular hexagonal blood treatment region has a high blood recovery rate, and the blood recovery rate decreases in the order of a circle and a rectangle.

  The outer joint portion 6 seals the container 3 in the thickness direction of the filter 10 in order to more reliably protect the filter medium 1 from the external environment. The outer joint portion 6 is provided so as to form the outer periphery of the regular hexagonal container 3.

[Method for producing blood processing filter]
First, a sheet-form filter medium material having the ability to adsorb aggregates and leukocytes contained in blood is prepared, and this is cut into a predetermined regular hexagon to obtain the filter medium 1. The filter material can be cut with a blade, an ultrasonic cutter or a laser cutter.

  In the case of obtaining the regular hexagonal filter medium 1 by cutting the filter medium material, the material loss can be minimized by cutting the filter medium material 1A along the broken line L as shown in FIG. it can.

  As a material for a filter medium, a material having flexibility is preferable, such as a fiber structure such as a nonwoven fabric manufactured by a melt blow method, a porous body (sponge-like structure) having continuous pores, a porous film, etc. Is mentioned. As a filter material, a material composed of a fiber structure, a porous body or a porous membrane, or a material obtained by using these as a base material and chemically or physically modified on the surface thereof may be used. As the filter material, a fiber structure, a porous body, or a porous membrane may be used as a single layer, or a combination of these may be used as a plurality of layers.

Examples of the material for the fiber structure include polyester, polypropylene, polyamide, polyacrylonitrile, polytrifluoroethylene, polymethyl methacrylate, polystyrene, and the like. When a fiber structure is used as the filter medium 1 or its base material, the fiber structure may be composed of fibers having a substantially uniform fiber diameter, and is disclosed in WO 97/232266. A form in which a plurality of types of fibers having different fiber diameters are mixed may be used. In order to reduce the white blood cell count of the blood after filtration to 5 × 10 ⁶ cells / unit or less, the average fiber diameter of the fibers forming the filter medium 1 is preferably 3.0 μm or less, more preferably 0.9 μm. ~ 2.5 μm.

Examples of the material of the porous body or porous membrane include polyacrylonitrile, polysulfone, cellulose acetate, polyvinyl formal, polyester, polyacrylate, polymethacrylate, and polyurethane. In order to reduce the white blood cell count of the blood after filtration to 5 × 10 ⁶ / unit or less, the average pore diameter of the porous body or the porous membrane is preferably 2 μm or more and less than 10 μm.

  A flexible resin sheet or film for forming the container 3 is prepared. Examples of the material of the container 3 include soft polyvinyl chloride; polyurethane; ethylene-vinyl acetate copolymer; polyolefin such as polyethylene and polypropylene; hydrogenated product of styrene-butadiene-styrene copolymer; styrene-isoprene-styrene copolymer And a thermoplastic elastomer such as a polymer or a hydrogenated product thereof; and a mixture of a thermoplastic elastomer and a softening agent such as polyolefin or ethylene-ethyl acrylate. From the viewpoint of good permeability of high-pressure steam and electron beam for sterilization, and toughness that can withstand the load during centrifugation, as materials for container 3, soft vinyl chloride, polyurethane, polyolefin, and these A thermoplastic elastomer containing as a main component is particularly suitable.

  By forming the inner joint 5, the filter medium 1 and the container 3 are joined together to define the region R of the filter 10. The inner joint portion 5 can be formed by, for example, high frequency welding. Similarly to the inner joint 5, the outer joint 6 can be formed by high frequency welding. The inlet port 7a and the outlet port 8a may be provided at predetermined positions of the container 3 by welding, for example, and the region R and the outside may be communicated with each other through the inlet 7 and the outlet 8. The filter 10 is manufactured through the above process.

  The filter 10 according to the present embodiment has the following effects. That is, since the outlet port 8a is formed immediately above the apex C2 on the lower side of the inner joint portion 5, most of the blood in the region R is discharged from the outlet 8 by gravity. For this reason, according to the filter 10, a sufficiently high blood recovery rate can be realized. On the other hand, in the conventional filter 50 shown in FIGS. 7 and 8, since the inner joint portion 55 is rectangular, blood tends to remain near the bottom 55a of the inner joint portion 55.

  A region R of the filter 10 is defined by sides S1 and S2 extending in the vertical direction. These sides S1 and S2 are considered to contribute to the stable flow of blood in the region R. As a result, it is presumed that the blood recovery rate of the filter 10 is higher than that of the conventional filter shown in FIG.

  In the filter 10, the shape of the filter medium 1 is a regular hexagon, so that in the process of obtaining the filter medium 1 by cutting the material for the filter medium, the amount of waste of the filter medium and the cutting time can be minimized. Yes (see FIG. 4). For this reason, the filter 10 can be manufactured efficiently and at low cost. In addition, even when the shape of the filter medium is rectangular, when cutting a plurality of filter media from the filter medium material, there are many parts where the line to be cut forms a common side with the adjacent filter medium, so the amount of debris discarded In addition, the cutting time can be sufficiently suppressed. On the other hand, when the shape of the filter medium is a circle or an ellipse, the cutting efficiency becomes insufficient and the time required for cutting becomes long because there are few portions that form a common peripheral edge with the adjacent filter medium. .

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment. For example, in the said embodiment, although the case where the shape of the filter medium 1 was made into a regular hexagon was illustrated, if it is a shape which can fully obtain the effect of this invention, it will not be limited to a regular hexagon. For example, the shape of the filter medium 1 and the inner joint 5 may be a hexagon whose left and right sides in the vertical direction are longer than the other sides.

  More specifically, as shown in FIG. 5, the shape of the inner joint portion 5 includes a rectangular region R1 between two sides extending in parallel to each other in the vertical direction, and an upper isosceles triangle adjacent above the rectangular region R1. It may be a hexagon formed of a region R2 and a lower isosceles triangular region R3 adjacent below the rectangular region R1. The angle α (angle formed between the side S3 of the lower isosceles triangle and the horizontal direction) shown in FIG. 5 is preferably 20 to 40 °, and preferably 25 to 35 °, from the viewpoint of reducing the residual blood amount. Is more preferable. Note that the angle β (the angle formed between the side S4 of the upper isosceles triangle and the horizontal direction) may be the same as or different from the angle α. From the viewpoint of the stability of blood flow in the region R, the angle β The angle is preferably 40 °, and more preferably 20 to 35 °.

  In the case where the joint is formed by high-frequency welding, it is usually preferable from the viewpoint of welding uniformity that the joint is continuously provided at a position where the distance from the center of the filter is as equal as possible. That is, high uniformity of welding can be achieved when the shape of the joint is circular. The uniformity of welding tends to be insufficient in the order of circle, ellipse, hexagon, and rectangle.

ｒの値はなるべく大きいことが好ましいが、内側接合部が円形の場合の値０．５６が最大値である。ｒの値は０．５１以上であることが好ましく、０．５３以上であることがより好ましい。内側接合部の形状を六角形にした場合、矩形の場合と比較して接合部の強度が向上し、フィルターの安全性が向上するという利点がある。 When the liquid is introduced into the filter, the pressure on the inlet side increases, so that the inner joint portion 5 is required to have a sufficiently high strength. The strength of the inner joint portion 5 depends on the shortest distance from the center of the filter to the inner joint portion 5, and the longer the distance, the higher the strength. When the shortest distance from the filter center to the inner joint 5 is b and the effective filtration area (area R) S, the strength depends on the joint position r expressed by the equation (1).

The value of r is preferably as large as possible, but a value of 0.56 when the inner joint is circular is the maximum value. The value of r is preferably 0.51 or more, and more preferably 0.53 or more. When the shape of the inner joint portion is hexagonal, there is an advantage that the strength of the joint portion is improved and the safety of the filter is improved as compared with the rectangular shape.

Furthermore, in the said embodiment, although the case where the shape of the container 3 was a regular hexagon was illustrated, the shape is not limited to a regular hexagon. The shape of the container 3 may be, for example, a rectangle (see FIGS. 6A and 6B). The shape of the container 3 may be hexagonal, elliptical or circular. However, the disposal amount of the fragments of the container 3 generated at the time of manufacture and the time required for cutting increase in the order of rectangle, hexagon, ellipse, and circle. That is, when the shape of the container 3 is rectangular, the loss of material and time in the manufacturing process is the smallest.

  The present invention will be described in more detail and specifically by examples, but the scope of the present invention is not limited by these examples.

[Manufacturing process and related evaluation items]
First, a filter material (size 1350 mm × 1350 mm) composed of a laminate of a plurality of nonwoven fabrics was prepared. The filter medium was cut to produce a filter medium. The number (filtering number) of filter media that can be taken from the filter media material of the above size was evaluated. Note that the number of filters is the product of the number of filter media that can be taken vertically and the number of filter media that can be taken horizontally.

Further, the time required for cutting the filter medium was evaluated, and the time was determined as follows. That is, the speed at the time of cutting the filter medium material with a laser cutter was set to 50 mm / second for the straight portion and 40 mm / second for the curved portion, and the total time was defined as the cut time (minutes). The area of debris remaining after the filter medium was cut out from the filter medium material was defined as the amount of waste (mm ² ). Note that the shorter the cutting time, the higher the productivity, and it is desirable that the cutting time is within 15 minutes. From the viewpoint of production cost, it is desirable that the discard rate (discarded amount / area of the filter medium material) is 10% or less.

  Next, the flowability test of a filter using a polyvinylpyrrolidone aqueous solution (PVP solution) simulating blood will be described. The outlet of the storage bag and the filter inlet port were connected by a tube, and the outlet port and the inlet of the collection bag were connected by a tube. Thereby, as shown in FIG. 1, the filter which concerns on this invention has been arrange | positioned between the storage bag and the collection | recovery bag. As the tube, a tube made of soft vinyl chloride having an inner diameter of 3 mm and an outer diameter of 4.2 mm was used. The length of the upstream tube was 50 cm, and the length of the downstream tube was 50 cm.

  After closing the upstream tube with a clamp, 300 g of an aqueous PVP solution was placed in a storage bag. The PVP solution is obtained by adding polyvinylpyrrolidone (PVP, Wako Pure Chemical Industries, Ltd., K-90) to distilled water for injection (manufactured by Otsuka Pharmaceutical Co., Ltd.), and having a viscosity of 16-18 mPa · s at a temperature of 22-26 ° C. It was obtained by adjusting.

  The total head is the sum of the upstream head (vertical distance from the lower end of the storage bag to the filter inlet), the head head from the inlet to the outlet of the filter, and the downstream head (vertical distance from the filter outlet to the lower end of the collection bag). Adjusted to 1.0 m. After suspending the storage bag containing the PVP aqueous solution, the collection bag was allowed to stand on the balance, the clamp closing the upstream tube was opened, and filtration was started. The time from when the clamp was released until the PVP solution reached the collection bag was defined as the priming time.

  The time from when the PVP solution reached the collection bag until the PVP solution in the storage bag was emptied was defined as the filtration time. After the storage bag is emptied, reading the value of the balance on which the collection bag is placed every minute. When the fluctuation of the value of the balance for 1 minute becomes 0.5 g or less, the collection is finished. The value of the balance was taken as the recovered amount.

  It is preferable that the filtration time is short, and it is desirable that the filtration time can be shortened as compared with public goods having the same filtration area (Comparative Examples 1 and 2 described later). Further, the recovery rate is desirably 85% or more, and more desirably 90% or more.

[Example 1]
The first filter element is a polyester nonwoven fabric having a fiber diameter of 12 μm, a basis weight of 30 g / m ² , and a thickness of 0.189 mm; and a fiber diameter of 1.2 μm, a basis weight of 40 g / m ² and a polyester nonwoven fabric having a thickness of 0.235 mm A second filter element was prepared for each. 4 sheets of first filter elements on the blood inlet side, 26 sheets of second filter elements on the blood outlet side, and 4 sheets of first filter elements on the blood outlet side. A filter medium material was obtained. This filter material was cut to obtain a regular hexagonal filter medium having a side of 50.2 mm.

  A filter according to the present embodiment is formed by arranging flexible resin sheets on both surfaces of a filter medium and forming an inner joint portion by a high frequency welding method so that the blood treatment region is a regular hexagon having a side of 40.4 mm. Got. The inlet of the filter was provided at a position 17 mm away from the center of the blood treatment region. On the other hand, the outlet of the filter was provided at a position 17 mm below the center of the blood treatment region (see FIG. 2). Table 1 shows the data regarding the filter configuration, the evaluation results of the manufacturing process, and the results of the flowability test.

[Example 2]
A filter was prepared in the same manner as in Example 1 except that a regular hexagonal filter medium (one side: 57.2 mm) was prepared from the filter medium material, and the shape of the blood treatment region was a regular hexagon (one side: 46.2 mm). Produced. Table 1 shows the data regarding the filter configuration, the evaluation results of the manufacturing process, and the results of the flowability test.

[Comparative Example 1]
A filter was prepared in the same manner as in Example 1 except that a rectangular filter medium (74 mm × 91 mm) was prepared from the filter medium material and the shape of the blood treatment region was rectangular (57 mm × 74 mm) (FIG. 7). Table 2 shows data relating to the configuration of the filter, evaluation results of the manufacturing process, and results of the flowability test.

[Comparative Example 2]
A filter was prepared in the same manner as in Example 1 except that a rectangular filter material (84 mm × 104 mm) was prepared from the filter material and the shape of the blood treatment region was rectangular (65 mm × 85 mm) (FIG. 7). Table 2 shows data relating to the configuration of the filter, evaluation results of the manufacturing process, and results of the flowability test.

[Comparative Example 3]
A filter was prepared in the same manner as in Example 1 except that a circular filter medium (radius 45.1 mm) was prepared from the filter medium material and the shape of the blood treatment region was circular (radius 36.6 mm). . Table 2 shows data relating to the configuration of the filter, evaluation results of the manufacturing process, and results of the flowability test.

[Comparative Example 4]
A filter was prepared in the same manner as in Example 1 except that a circular filter medium (radius 51.4 mm) was prepared from the filter medium material and the shape of the blood treatment region was circular (radius 41.9 mm). . Table 2 shows data relating to the configuration of the filter, evaluation results of the manufacturing process, and results of the flowability test.

[Comparative Example 5]
A filter was prepared in the same manner as in Example 1 except that a square (diamond) filter medium (82 mm × 82 mm) was prepared from the filter medium material, and the shape of the blood treatment region was square (65 mm × 65 mm). did. The filter of this comparative example was tested by providing an inlet and an outlet on one diagonal line in the blood treatment region and arranging the diagonal line in the vertical direction (see FIG. 9A). Table 3 shows data relating to the filter configuration, manufacturing process evaluation results, and flowability test results.

[Comparative Example 6]
Except that a square (diamond) filter medium (93.3 mm × 93.3 mm) was prepared from the filter medium material, and the shape of the blood treatment region was a square (74.3 mm × 74.3 mm), Example A filter was prepared in the same manner as in 1. The filter of this comparative example was tested by providing an inlet and an outlet on one diagonal line in the blood treatment region and arranging the diagonal line in the vertical direction (see FIG. 9A). Table 3 shows data relating to the filter configuration, manufacturing process evaluation results, and flowability test results.

[Comparative Example 7]
A filter was produced in the same manner as in Example 1 except that a square filter medium (82 mm × 82 mm) was prepared from the filter medium material and the shape of the blood treatment region was square (65 mm × 65 mm). In addition, the inlet and outlet of the filter of this comparative example were provided so that the side extending in the vertical direction defining the blood processing region and the line connecting the inlet and outlet were parallel (see FIG. 9B). Table 3 shows data relating to the filter configuration, manufacturing process evaluation results, and flowability test results.

[Comparative Example 8]
A square filter medium (93.3 mm × 93.3 mm) was prepared from the filter medium material, and the shape of the blood treatment region was changed to a square (74.3 mm × 74.3 mm). Thus, a filter was produced. In addition, the inlet and outlet of the filter of this comparative example were provided so that the side extending in the vertical direction defining the blood processing region and the line connecting the inlet and outlet were parallel (see FIG. 9B). Table 3 shows data relating to the filter configuration, manufacturing process evaluation results, and flowability test results.

  The filter according to the present invention is useful mainly as a filter for removing microaggregates, leukocytes and / or platelets from blood for transfusion. The filter of the present invention can also be applied to extracorporeal circulating leukocyte removal therapy.

DESCRIPTION OF SYMBOLS 1 ... Filter material, 3 ... Container, 5 ... Inner junction part (1st junction part), 6 ... Outer junction part (2nd junction part), 7 ... Inlet, 8 ... Outlet, 10 ... Filter, R ... Blood Processing area.

Claims (4)

A blood treatment filter,
A sheet-like filter medium;
A container made of a flexible material and containing the filter medium;
A first joint that is formed over the entire periphery of the peripheral portion of the filter material, and joins the filter material and the container in the thickness direction of the filter to define a blood treatment region;
An inlet provided on one side of the container;
An outlet provided on the other side of the container;
With
The filter in which the shape of the first joint is a hexagon and the shape of the filter medium is also a hexagon.   When the filter is arranged in the vertical direction so that the inlet is located above and the outlet is located below, the shape of the filter medium is a rectangular region between two sides extending in parallel to each other in the vertical direction; 2. The filter according to claim 1, wherein the filter has a hexagonal shape composed of an upper isosceles triangular area adjacent above the rectangular area and a lower isosceles triangular area adjacent below the rectangular area.   When the filter is arranged vertically so that the inlet is located above and the outlet is located below, the area of the blood treatment region below the outlet is 10% or more and less than 26% of the whole region. The filter according to claim 1 or 2, wherein   The filter as described in any one of Claims 1-3 further provided with the 2nd junction part which joins the peripheral part of the said container in the thickness direction of the said filter.

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