JP2008086352A - Blood processing filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible blood processing filter in which an exit side container is not in close contact with a filter element to prevent the flow of blood from being blocked and which is excellent in pressure resistance and peeling resistance. <P>SOLUTION: The blood processing filter is composed of: a blood entrance side container on a flexible sheet 8, a blood exit side container 2'; and sheet-like filter elements 3 and 4 for removing microaggregates and leukocytes or the microaggregates, the leukocytes and thrombocytes from the blood. The sheet-like filter elements 3 and 4 are clamped by the respective containers and fixed to the respective containers at the peripheral edge part, and the inside is partitioned into an entrance side space and an exit side space. Between the sheet-like filter elements and the exit side container, a spacer, whose thickness is 0.5 to 5 mm, aperture ratio is 30 to 70% and total area including an aperture part is 10 to 90% by an area ratio to an effective filtration area, is not fixed to any of the filter elements and the respective containers at the peripheral edge part of the sheet-like filter elements. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a blood treatment filter for removing undesirable components such as aggregates and leukocytes from blood. In particular, it relates to a precise and disposable blood treatment filter used for the purpose of removing microaggregates and white blood cells that cause transfusion side effects from whole blood preparations for blood transfusion, red blood cell preparations, platelet preparations, plasma preparations, etc. In particular, the present invention relates to a blood processing filter in which a flexible material is used as the material of the container.

  It is becoming common for whole blood collected from a donor to be separated into blood component preparations such as erythrocyte preparations, platelet preparations, plasma preparations, etc., stored, and then transfused. In addition, since microaggregates and leukocytes contained in these blood products cause various side effects of blood transfusion, these undesired components are removed before blood transfusion or blood transfusion, or after blood collection, these are undesirable. Many methods are used for blood transfusion after storage after removing the components.

  The most common method for removing leukocytes from a blood product is to treat the blood product with a leukocyte removal filter. Conventionally, blood product processing using this leukocyte removal filter has often been performed at the bedside during blood transfusion operations, but in recent years, for the purpose of quality control of leukocyte removal products and improved stability of leukocyte removal processing. It is becoming common for blood centers to be performed before storage. For the leukocyte removal filter, a filter element made of a nonwoven fabric or a porous material is filled in a container made of a material having excellent flexibility and vapor permeability, which is the same as or similar to that used for a bag of a blood collection set. Two types are used: a leukocyte removal filter for a flexible container, and a leukocyte removal filter for a hard container in which a filter element made of a nonwoven fabric or a porous material is filled in a hard container such as polycarbonate.

  Normally, when processing blood with these leukocyte removal filters, the bag containing the blood product to be processed, which is connected to the blood inlet side of the filter via a conduit, is positioned 20 to 100 cm higher than the filter. The blood product is passed through the filter by the action of gravity, and the filtered blood product is stored in a collection bag connected to the blood outlet side of the filter via a conduit. In the case of the leukocyte removal filter of the flexible container, a pressure loss occurs due to the resistance of the filter element during the filtration, and the space on the filter inlet side becomes a positive pressure. In the case of a filter made of a flexible container, since the container is flexible, this positive pressure causes the container to expand in a balloon shape, and the filter element is pressed against the container on the outlet side.

  On the other hand, the gap between the outlet side container and the filter element is for storing blood after filtration, which is placed at a position 50 to 100 cm lower than the normal filter, as blood in the conduit connected to the outlet flows down by gravity. In this case, the negative pressure is reversed by this action, the flexible container is in close contact with the filter element, and the opening of the blood outlet is blocked. That is, blood tries to flow out of the filter, but it is difficult for blood to flow out because the opening is closed.

As a method for solving this problem, the prior art includes a method of preventing adhesion by inserting a soft PVC tube called a connecting rod between the filter element and the outlet side container (Patent Document 1), A method for preventing adhesion by providing unevenness with a difference of 0.2 to 2 mm (Patent Document 2), a method for inserting a knit fiber screen or the like (Patent Document 3), a method for arranging a mesh or a protrusion (Patent Document) 4) etc. are proposed.
However, in the method of inserting the connecting rod described in Patent Document 1, a large number of connecting rods are required to maintain the space between the filter element and the outlet side container, which complicates the manufacturing process. In addition, the cost increases. As described in Patent Document 3 and Patent Document 4, the method of inserting a screen, mesh or protrusions not only increases the cost, but also welds thick fibers such as a screen and mesh to a flexible container. In such a case, the fibers cannot be sufficiently crushed by ordinary welding, which causes problems such as leakage. Conversely, when welding is performed under conditions stronger than usual, the strength of the flexible container is lowered. Moreover, when using a protrusion-like thing, there exists a danger of causing the welding defect of a container by inserting another member. Although the method disclosed in Patent Document 2 was proposed as a method for solving the problem of the method of inserting a connecting rod, a screen, a mesh, or a protrusion, uniform welding of a container having an uneven portion is difficult and stable. It is difficult to obtain the strength.

As a flexible blood treatment filter that prevents blood flow from being blocked and has excellent pressure resistance and peel resistance, it is converted to a thickness of 1 cm between the first and second filter elements and the outlet side container. A blood treatment filter in which a third filter element having an air permeability of 3 to 40 cc / cm ² / sec and a thickness of 0.04 to 0.25 cm is arranged has been proposed (Patent Document 5). . Compared to conventional filters, this blood treatment filter has sufficient strength against pressure during filtration and stress during centrifugation, and is effective in shortening filtration time. Since the fluid flow resistance is high when flowing through the filter element in the direction parallel to the filtration surface, the blood flow is inhibited, so that a sufficient effect is not necessarily obtained. Moreover, sufficient effect is not acquired for the same reason also about the filter (patent document 6) which has arrange | positioned the porous body which has the hole diameter of 50-5000 micrometers, or a nonwoven fabric.
European Patent Application No. 0526678 JP-A-11-216179 JP-A-7-267871 WO95 / 17236 pamphlet JP 2003-180822 A International Publication No. 02/04045 Pamphlet

  The problem of the present invention is that the sheet-like filter element is pressed against the outlet-side container by the positive pressure on the inlet side generated during filtration and / or the outlet-side container sticks to the sheet-like filter element by the negative pressure on the outlet side. It is an object of the present invention to provide a blood processing filter in which a side container is prevented from sticking to a sheet-like filter element. More specifically, by having the above-described action, the blood flow is not hindered, that is, the blood flow is uniform and the blood treatment speed is flexible and the blood treatment speed is high. It is an object of the present invention to provide a flexible blood treatment filter that is excellent in properties and peel resistance and has sufficient strength against pressure during filtration and stress during centrifugation.

  It is another object of the present invention to provide a flexible blood processing filter that can withstand higher pressures generated by squeezing operation or rapid filtration by a pump and does not cause leakage, rupture, or peeling.

  As a result of diligent research to solve the above problems, the present inventors have, for example, a sheet-like spacer provided between the outlet-side container and the sheet-like filter element and provided with a notch at the center of the effective filtration surface. It has been found that the flow resistance when blood flows decreases, the space through which the blood passes is maintained by the spacer even when the outlet side is under negative pressure, and the blood flow is not hindered. As a result, blood not only flows uniformly through the filter medium, and the filtration time is greatly shortened, but also the filter medium is effectively used, so that the filtration efficiency is dramatically improved and another member is welded. It has been found that a blood treatment filter having a remarkably excellent strength in terms of pressure resistance and peeling resistance can be obtained without causing poor welding of the container.

That is, the present invention includes the following.
(1) An inlet side container in which a blood inlet is attached to a flexible sheet, an outlet side container in which a blood outlet is attached to a flexible sheet, and microaggregates and leukocytes or microaggregates and leukocytes and platelets from blood. The sheet-like filter element is sandwiched between the respective containers and fixed to the respective containers at the peripheral edge thereof, so that the inside is the inlet side space and the outlet side. In the blood processing filter that is partitioned into a space, between the sheet-like filter element and the outlet side container, the thickness is 0.5 to 5 mm, the porosity is 30 to 70%, and the total area including the aperture is A spacer having an area ratio of 10 to 90% with respect to the effective filtration area is arranged, and the spacer is fixed to both the filter element and the respective containers at the peripheral edge of the sheet-like filter element. Blood treating filter, characterized that no.
(2) The blood processing filter according to (1), wherein the spacer covers a surface obtained by shrinking the effective filtration surface shape by 1/16 about the center of gravity of the effective filtration surface.
(3) The blood processing filter according to (1) or (2), wherein a part of the periphery of the spacer and the outlet-side flexible container are joined at a portion other than the fixed portion of the filter element.
(4) The blood processing filter according to any one of (1) to (3), wherein a material of the spacer is the same as that of the flexible container.

  In the blood treatment filter of the present invention, the sheet-like filter element is pressed against the outlet-side container by the positive pressure on the inlet side and / or the negative pressure on the outlet side generated during filtration, or the outlet-side container is stuck to the sheet-like filter element. In this case, the outlet side container is not in close contact with the sheet-like filter element, so that a flexible blood processing filter is obtained in which the blood flow is not hindered.

  In addition, it is a flexible blood treatment filter that is excellent in pressure resistance and peel resistance and has sufficient strength against pressure during filtration and stress during centrifugation. Furthermore, it was able to withstand even higher pressures generated by squeezing operation and rapid filtration with a pump, resulting in a flexible blood treatment filter that does not leak, rupture or peel off.

The present invention is described in detail below.
The overall shape of the blood treatment filter of the present invention is a flat plate shape, and the plane may be any of a rectangular shape, a disk shape, an oblong plate shape, etc., but in order to reduce material loss during filter production, A rectangular shape is preferred. Squares and rhombuses are also considered as a kind of rectangular shape.

  The flexible container used in the present invention is preferably formed from a sheet-like molded product made of a flexible synthetic resin, and more preferably a thermoplastic resin. The sheet shape is required because the filter element and the flexible container or the flexible container need to have a uniform sheet thickness, and the bonded portion has a uniform thickness. If so, even if a flexible container is made from a sheet or film, or an injection-molded product, it can be regarded as being formed from a sheet-like molded product.

  Any material commercially available as a sheet or film can be used in the flexible container of the present invention. For example, soft polyvinyl chloride, polyurethane, ethylene-vinyl acetate copolymer, polyolefin such as polyethylene and polypropylene, hydrogenated styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer or hydrogenated product thereof Suitable materials include thermoplastic elastomers such as products, and mixtures of thermoplastic elastomers and softeners such as polyolefin and ethylene-ethyl acrylate. Since it comes into contact with blood, the material of the flexible container is preferably soft vinyl chloride, polyolefin, and thermoplastic elastomers containing these as the main components, which are used as materials for medical products such as blood bags, More preferred is soft vinyl chloride.

  The sheet-like filter element of the present invention is for removing microaggregates and leukocytes, or microaggregates, leukocytes and platelets from blood, and is a fibrous porous medium such as nonwoven fabric or woven fabric, or a sponge-like structure. A known filtration medium such as a porous body having three-dimensional network-like continuous pores such as an object can be used. Those which create a space between the sheet-like filter element and the flexible container, such as a mesh and a screen, are not applicable because they have poor weldability. Examples of the material for these filter elements include polypropylene, polyethylene, styrene-isobutylene-styrene copolymer, polyurethane, polyester, and the like. When the filter element is a nonwoven fabric, it is particularly preferable from the viewpoint of productivity.

  The sheet filter element used in the present invention may be a single sheet filter element or a plurality of sheet filter elements. In the case of a plurality of sheet-like filter elements, a first sheet-like filter element that removes microaggregates arranged upstream, and leukocytes or leukocytes and platelets arranged downstream of the first sheet-like filter element are removed. Preferably, it comprises a second sheet-like filter element. For example, a sheet-like filter element made of a nonwoven fabric having a fiber diameter of several to several tens of μm is disposed on the inlet side as a first sheet-like filter element for removing aggregates, and then the fiber diameter is 0.3 to 3 When a sheet filter element made of 0.0 μm non-woven fabric is arranged as a second sheet filter element for removing leukocytes or leukocytes and platelets, and a post filter having a specific space on the downstream side is laminated and used. There is also.

  Each of the first and second sheet-like filter elements may further be constituted by a plurality of types of sheet-like filter elements, or only one of them may be constituted by a plurality of types of sheet-like filter elements. For example, a first filter element made of a nonwoven fabric having a fiber diameter of 30 to 40 μm and / or a nonwoven fabric having a fiber diameter of 10 to 20 μm is arranged on the upstream side, and the fiber diameter is 1 on the downstream side of the first sheet-like filter element. You may arrange | position and use the 2nd sheet-like filter element which consists of a nonwoven fabric of 5-2.5 micrometers, and / or a nonwoven fabric whose fiber diameter is 0.5-1.8 micrometers. Moreover, although the nonwoven fabric of a thick fiber diameter and the nonwoven fabric of a thin fiber diameter may be arrange | positioned alternately, it is preferable that the nonwoven fabric of a thick fiber diameter is arrange | positioned upstream.

Hereinafter, the detailed structure of the filter of the present invention will be described with reference to the drawings.
FIG. 2 is an overall view showing an example of the blood processing filter of the present invention. As shown in FIG. 2, in the present invention, among the flexible containers, the container on the side for introducing the blood to be filtered is the inlet side container 2, and the container on the side from which the filtered blood is led out is the outlet side container. 2 ′. These are generally symmetrical structures or the same structure, but need not be limited thereto.
The inlet side container 2 is provided with a blood inlet 1 through which liquid flows from the outside to the inside of the container without leakage, and the outlet side container 2 ′ is attached with blood outlet 5 through which liquid flows from the inside of the container to the outside without leakage. It has been. In such a container structure, a flexible sheet for a container in which one opening is provided in advance is prepared, and a separately formed blood inlet 1 (blood outlet 5) is bonded or welded to the container opening. Obtained by dense installation. At least the blood outlet 5 of the blood inlet 1 and the blood outlet 5 is provided on the inner side of the peripheral portion to which the inlet side container 2, the outlet side container 2 ′ and the sheet-like filter elements 3 and 4 described later are fixed. In some cases, it is more effective in the present invention. The outer opening 1a (5a) and the inner opening 1b (5b) of the blood inlet 1 (blood outlet 5) face each other as shown in FIG. 6A, and each other as shown in FIG. 6B and FIG. The outer opening 1a (5a) may be shaped so as to be substantially perpendicular to the sheet surface of the sheet-like filter element without facing each other.

  In the blood processing filter of the present invention, the sheet-like filter element is sandwiched between the respective containers and fixed to the respective containers at the peripheral edge thereof, thereby dividing the interior into an inlet side space and an outlet side space. It has been. This fixing is performed by welding.

  The welding form of the flexible container and the sheet-like filter element of the present invention is, for example, a container welding type in which the flexible container is directly welded to the sheet-like filter element and the post filter, and the filter element is once formed into a sheet-like flexible frame. After the welding, any form such as a frame welding type in which the frame is welded to a flexible container may be used. The container welding type is preferable in that the number of manufacturing steps is small and the loss of raw materials is small.

1 and 2 are views showing a process for producing a container welding type filter. The first and second sheet-like filter elements 3 and 4 are sandwiched between the inlet-side container 2 provided with the blood inlet 1 and the outlet-side container 2 ′ provided with the blood outlet 5 (see FIG. 1), A container-welded blood treatment filter device can be obtained by double-welding the peripheral edge. The double welding means that the first seal area 6 where the sheet-like filter element and the inlet side (outlet side) container are welded, and the second seal area 7 where the inlet side container and the outlet side container are directly welded, To form.
3 and 4 are diagrams showing a process for producing a frame welding type filter. After the first and second sheet-like filter elements 3 and 4 are sandwiched between the frame-like flexible sheet 8 and the frame portion is welded, this is connected to the inlet-side container 2 provided with the blood inlet 1 and the blood outlet 5. (See FIG. 3), and the inlet side container 2, the frame-shaped flexible sheet 8 and the outlet side container 2 ′ are welded at the peripheral edge (see FIG. 4). See), a frame-welded blood treatment filter device can be obtained.

  The flexible container or the frame-like flexible sheet of the present invention and the sheet-like filter element can be welded by a method such as high-frequency welding, internal welding by ultrasonic welding, or external welding by heat sealing. High frequency welding is preferable in terms of excellent weldability. When welding is performed, the melted flexible sheet material enters the outermost layer of the sheet-like filter element, that is, the gap of the sheet-like filter element in contact with the flexible sheet, and after cooling, each fiber is welded like an anchor. It is important that the surface be formed. Therefore, it is preferable to increase the pore diameter (void) by increasing the fiber diameter of the outermost filter element.

  The melting point of the outermost sheet-like filter element is preferably higher than the melting point of the flexible sheet material. This is because even when the flexible sheet material and the sheet-like filter element are not adhesive, the flexible sheet material melts and enters the outermost filter element, and the inner-layer sheet-like filter element is the outermost layer. This is because the adhesive portion between the flexible sheet material and the sheet-like filter element can obtain high strength by adhering to the filter element. In the case of the combination of the flexible sheet material and the material having adhesiveness to the sheet-like filter element, the fiber diameter, the hole diameter, and the melting point need not be such.

The spacer of the present invention is a sheet-like molding having a thickness of 0.5 to 5 mm, a hole area ratio of 30 to 70%, and a total area including the hole part of 10 to 90% in terms of the area ratio to the effective filtration area. Say things.
In the present invention, the spacer needs to have a thickness of 0.5 to 5 mm. When the thickness is less than 0.5 mm, the space through which the blood flows is small, so that the function as a spacer can hardly be exhibited, and the effect of improving the flow rate becomes small. On the other hand, if it exceeds 5 mm, blood remains inside the blood processing filter after the filtration is completed, and the amount of collected blood is reduced. Further, when the welded portion of the flexible container is melted by high frequency welding or the like at the time of welding, if the spacer is thick, the welded portion is pulled, so the thickness of the side of the welded portion is reduced. When the spacer is thin, it is possible to prevent the side of the welded portion from becoming thin, so that it is possible to prevent the occurrence of leaks and the like, and it is possible to prevent the occurrence of leaks due to the filter internal pressure that occurs during product use. Preferably it is 1-3 mm.

  In the present invention, the aperture ratio of the spacer is defined by (area of the aperture of the spacer / area including the aperture of the spacer) × 100. The larger the hole area ratio, the smaller the contact between the spacer and the sheet-like filter element and between the spacer and the inlet-side container or the outlet-side container, and the resistance when fluid flows between the sheet-like filter element and the flexible container. By reducing, the fluidity of the fluid is improved. Therefore, an opening efficiency of 30% or more is required. However, if the hole area ratio is too high, handling becomes difficult when handled industrially, so the opening effect needs to be 70% or less. That is, the opening efficiency of the spacer needs to be 30 to 70%. More preferably 30 to 60%, still more preferably 30 to 50%, even higher effects can be exhibited.

  In the present invention, if a spacer having an area including the opening portion of the spacer is 10% or more with respect to the effective filtration area of the filter element, the inlet side container or the outlet side container and the sheet-like filter element, or the flexible frame In addition, when the sheet-like filter element is welded, wrinkles of the sheet-like filter element that are generated due to melting, solidification, and contraction can be reduced. Moreover, it becomes possible to reduce a resistance with respect to the flow between an outlet side container and a sheet-like filter element, As a result, it becomes possible to obtain a high flow velocity.

  On the other hand, if a spacer with an area including the opening portion of the spacer of 90% or less with respect to the effective filtration area of the filter element is arranged, the spacer is fixed when fixing the peripheral edge of the sheet-like filter using a method such as high frequency welding. Since a sufficient distance can be secured in the part, the pressure resistance and peelability of the container are not lowered without the spacer being sandwiched between the fixed parts. Therefore, the area including the opening portion of the spacer needs to be 10 to 90% with respect to the effective filtration area of the filter element, more preferably 20 to 85%, and still more preferably 30 to 80%. Can be demonstrated.

  When the spacer is disposed, it is preferable that the periphery thereof be separated from the welded portion between the flexible container and the sheet-like filter element or the flexible frame and the sheet-like filter element by 5 mm or more. This is because it is possible to reliably prevent the sheet material from being sandwiched between the welded portions at the time of welding. In the case where the welded portion is not a straight line, there is no problem as long as the welded portion is separated by 5 mm or more assuming a parallel line. This size is affected by the spacer thickness at the time of welding, and the thickness of the side of the welded portion of the flexible container can be reduced to prevent leaks. It is possible to prevent the occurrence of leaks and the like.

  Here, the flow of blood in the blood processing filter will be described with reference to FIG. As shown by the arrows in FIG. 6, the blood flowing in from the blood inlet has a higher resistance of the sheet-like filter element, and the amount of blood flowing from the blood inlet is larger than passing through the sheet-like filter element. Thus, first, the gap with the inlet side container is filled. Subsequently, blood begins to pass through the sheet-like filter element, and this time, the filtered blood flows out from the blood outlet while filling the gap between the sheet-like filter element and the outlet side container. If this is seen from the plane side of the sheet-like filter element, the blood flowing in from the blood inlet covers the surface of the sheet-like filter element radially from directly under the inlet, while the filtered blood is on the opposite side of the sheet-like filter element. It flows from the surface to the blood outlet in an anti-radial manner.

  Also, in blood treatment filters, in order to make the blood flow inside the filter more efficient, the blood inlet and outlet are generally not symmetrical with respect to the surface of the sheet-like filter element, and are generally separated from each other. It is.

  Considering the above, since the flow of blood from the blood inlet direction to the outlet direction is likely to occur on the surface of the sheet-like filter element, the spacer is provided with longitudinal ribs along this blood flow direction (blood flow). It is preferable from the viewpoint of flowability to have an opening along the direction). For example, in the case of the rectangular filter shown in FIG. 6, a shape in which vertical ribs are provided in the longitudinal direction as shown in FIG. 7 is preferable. Although not shown, when the blood inlet and the blood outlet are symmetric in the center of the sheet-like filter element, the spacer preferably has a shape in which ribs extend radially from the center.

  Regarding the rib of the spacer, it is preferable to provide a lateral rib, that is, a short rib in the rectangle of FIG. The reason why the horizontal ribs are provided is that handling is easier when the entire ribs are integrated for industrial handling. Further, the horizontal ribs do not need to be orthogonal to the vertical ribs, and may be arranged so as to connect the vertical ribs. Both the vertical ribs and the horizontal ribs need not be straight, and there is no problem even if they are curved.

  The interval between the vertical ribs is preferably 1 to 7 mm. More preferably, it is 2-5 mm. This is because when the interval between the longitudinal ribs is less than 1 mm, the space through which blood flows is small and the effect of improving the flow velocity tends to be small. On the contrary, when the interval exceeds 7 mm, when the negative pressure in the outlet side space of the blood processing filter increases, the contact area between the outlet side container and the sheet-like filter element increases remarkably and functions as a spacer. Can hardly be exhibited. As a result, the effect of improving the flow rate tends to be small, and a reduction in the amount of collected blood tends to occur.

  On the other hand, the width of the vertical rib is preferably 1 to 10 mm. When the width of the longitudinal rib is less than 1 mm, the longitudinal rib is easily deformed when sandwiched between the sheet-like filter element and the flexible container, and the gap between the sheet-like filter element and the flexible container is maintained. There is a risk of disappearing. On the contrary, when the width exceeds 10 mm, the larger the contact, the greater the contact between the spacer and the sheet-like filter element, and the spacer and the flexible container, resulting in resistance to fluid flow. More preferably 1 to 7 mm, and even more preferably 1 to 5 mm, a higher effect can be exhibited.

  The spacer of the present invention is not necessarily arranged at the center of the effective filtration area of the sheet-like filter element. However, when the flexible container and the sheet-like filter element or the flexible frame and the sheet-like filter element are welded, wrinkles may occur in the sheet-like filter element in the process of melting, solidifying, and shrinking. Is a place where the surface obtained by shrinking the effective filter surface shape by 1/16 around the center of gravity with respect to the effective filter surface is large. For example, in the case of a rectangular shape, wrinkles are generated along the diagonal line, so that the vicinity of the intersection of the diagonal line is the place with the largest unevenness, which is the vicinity of the surface obtained by shrinking the effective filtration surface shape about 1/16 around the center of gravity. Therefore, it is preferable to insert a spacer in that portion because the flow resistance between the sheet-like filter element and the outlet side container can be reduced, and a high flow rate can be obtained. More preferably, when 1/9 or more is covered, a high flow rate can be obtained.

  It is preferable that the spacer is joined to the inside of the outlet side container other than the fixing portion of the sheet-like filter element at a part of the peripheral portion thereof. By doing so, when the sheet-like filter element and the flexible container and the flexible container and the flexible sheet-like frame are welded, the position of the spacer is shifted, and the spacer is welded with the spacer interposed therebetween. Can be avoided. Moreover, it can prevent that an effect falls by shifting | deviating from the wrinkle part of a filter medium during filtration of a fluid. As a bonding method, high frequency welding, ultrasonic welding, a method of melting and pasting materials such as heat seal, a method of pasting using an adhesive, and the like can be used. It is preferable to use a paste without melting the substance.

  When the material of the spacer is the same as the material of the flexible container, the workability is good because the adhesiveness is excellent when a part of the periphery of the spacer is fixed to the outlet side container.

[Example]
Hereinafter, although the blood processing filter of this invention is demonstrated in detail based on an Example, this invention is not limited by these.

(1) Blood processing filter flowability test method The blood processing filter of the present invention is disposed between a storage bag and a recovery bag, and the inlet side conduit connected to the storage bag is recovered to the blood inlet of the blood processing filter. The outlet side conduit connected to the bag was connected to the blood outlet of the blood treatment filter. Further, as each conduit, a tube made of vinyl chloride having an inner diameter of 3 mm and an outer diameter of 4.2 mm was used, and the length of the inlet side conduit was set to 35 cm and the length of the outlet side conduit was set to 85 cm. After closing the inlet-side conduit with a clamp, polyvinylpyrrolidone (hereinafter sometimes referred to as “PVP”, manufactured by Wako Pure Chemical Industries, Ltd.) is added to distilled water for injection (manufactured by Otsuka Pharmaceutical Co., Ltd.). 460 g of the PVP aqueous solution prepared at 0 mPa · S was put in a storage bag.

The entire system was suspended and the collection bag was allowed to stand on the balance, and then the clamp closing the inlet side conduit 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.
Furthermore, the time from when the PVP solution reached the collection bag until the PVP solution in the storage bag became empty was defined as the processing 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 terminated. The time from emptying to the end of recovery was taken as the recovery time, and the value of the balance at the end of the recovery was taken as the recovered amount.

(2) Leakage inspection method for blood processing filter This is a method of applying a certain pressure to the blood processing filter device to confirm the occurrence of leakage. The blood outlet was sealed by adhering a single piece of soft polyvinyl chloride tube. Connect a conduit with a pressure line to the blood inlet. Thereafter, the filter device is submerged in water at a temperature of 25 ° C., and 30 kPa of air is injected from the conduit while the filter device is submerged in water, and it is confirmed whether air leaks from the first seal area of the filter device. . Ten pieces are inspected, and the occurrence rate is defined as the leak occurrence rate.

A first filter element which 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, a second filter element which is a polyester nonwoven fabric having a fiber diameter of 1.2 μm, a basis weight of 40 g / m ² and a thickness of 0.235 mm. Each of the filter elements was composed of four first filter elements on the blood inlet side and outlet side, and 25 layers of the second filter elements sandwiched between them.
An inlet side flexible container made of a vinyl chloride resin sheet with a blood inlet, a sheet-like filter element, an opening having a size of 4 mm × 55 mm at the center of a vinyl chloride resin sheet having a thickness of 1.2 mm and a size of 45 mm × 65 mm Six spacers arranged at intervals of openings (width of vertical ribs) of 2 mm and outlet-side flexible containers made of vinyl chloride resin sheets with blood outlets were arranged in this order. In this way, with the sheet-like filter element and the spacer sandwiched between the inlet side flexible container and the outlet side flexible container, the spacer is arranged in the center of the effective filtration surface, so that the filter element does not sandwich the spacer. The container was welded so as to be integrated with the flexible container, and a container-welded blood treatment filter device having an effective filtration part with a plane size of 65 mm × 85 mm was prepared.
A flowability test was performed, and priming time, processing time, recovery time, and recovery amount were measured. Table 1 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak rate, and the results.

  Except for using a spacer in which six openings of dimensions 4 mm x 55 mm are arranged at intervals of the openings (width of vertical ribs) of 2 mm at the center of a vinyl chloride resin sheet of thickness 0.8 mm and dimensions 45 mm x 65 mm A filter was prepared by the same method as in Example 1, a flowability test was performed, and priming time, processing time, recovery time, and recovery amount were measured. Table 1 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak rate, and the results.

  In the center of a vinyl chloride resin sheet having a thickness of 1.2 mm and dimensions of 30 mm × 30 mm, a spacer was used in which four openings with dimensions of 3.75 mm × 25 mm were arranged at intervals of openings (width of vertical ribs) of 3 mm. Except for the above, a filter was prepared in the same manner as in Example 1, and the priming time, processing time, recovery time, and recovery amount were measured. Table 1 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak rate, and the results.

  Except for using a spacer in which six openings of dimensions 4 mm x 55 mm are arranged in the center of a vinyl chloride resin sheet having a thickness of 2.7 mm and dimensions of 45 mm x 65 mm with an interval of the openings (width of vertical ribs) of 2 mm. A filter was prepared by the same method as in Example 1, a flowability test was performed, and priming time, processing time, recovery time, and recovery amount were measured. Table 1 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak rate, and the results.

  In the center of a vinyl chloride resin sheet having a thickness of 1.2 mm and dimensions of 45 mm × 65 mm, there are six openings of 4 mm × 7 mm in the horizontal direction, six in the vertical direction, and intervals between the openings in the horizontal direction ( A filter was prepared in the same manner as in Example 1 except that spacers arranged with a width of the vertical ribs of 2 mm and an interval between the vertical opening portions (the width of the horizontal ribs) of 1.4 mm, and the flowability test was performed. Priming time, processing time, recovery time, and recovery amount were measured. Table 1 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak rate, and the results.

  In the center of a vinyl chloride resin sheet having a thickness of 1.2 mm and a size of 55 mm × 75 mm, a spacer in which seven openings of a size of 6.5 mm × 71 mm are arranged with an interval of the openings (width of the vertical rib) of 1 mm was used. Except for the above, a filter was prepared in the same manner as in Example 1, a flowability test was performed, and priming time, processing time, recovery time, and recovery amount were measured. Table 1 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak rate, and the results.

[Comparative Example 1]
A filter was prepared in the same manner as in Example 1 except that no spacer was arranged, and priming time, processing time, recovery time, and recovery amount were measured. Table 2 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak occurrence rate, and the results.

[Comparative Example 2]
Example except for using a spacer in which six openings of dimensions 4 mm x 55 mm are arranged at intervals of the openings (width of vertical ribs) of 2 mm in the center of a sheet of vinyl chloride resin of thickness 7 mm and dimensions 45 mm x 65 mm A filter was prepared by the same method as in Example 1, and the priming time, processing time, recovery time, and recovery amount were measured. Table 2 shows the open efficiency, the ratio of the total area including the opening to the effective filtration area, the leak occurrence rate, and the results.

From the results of Table 1, when the spacer was not inserted (Comparative Example 1), both the processing time and the recovery time were long and there was a concern about operational problems. Further, when the spacer thickness is larger than necessary (Comparative Example 2), the thickness of the flexible container side becomes thin when the filter element and the peripheral edge of the container are welded by a normal operation. There was concern about the occurrence of defective products.
On the other hand, in the case where the spacer has a specific size and arrangement, those disadvantages are solved.

  The blood treatment filter of the present invention is useful as a filter for removing microaggregates and leukocytes or microaggregates, leukocytes and platelets from blood for transfusion mainly at the site of blood transfusion treatment. The filter is also useful as a filter used for extracorporeal circulating leukocyte removal therapy.

The cross-sectional schematic diagram in which each component was laminated | stacked before producing the container welding type blood processing filter. The cross-sectional schematic diagram which shows the example of the filter apparatus for blood processing of this invention produced by welding the laminated body of FIG. The cross-sectional schematic diagram in which each component was laminated | stacked before producing the flame welding type filter for blood processing. The cross-sectional schematic diagram which shows the example of the filter apparatus for blood processing of this invention produced by welding the laminated body of FIG. Sectional drawing which shows the example when the flexible container of another specification of FIG. 4 is used. Schematic diagram showing the flow of blood in the blood treatment filter Example of spacer shape of the present invention

Explanation of symbols

1: Blood inlet 2: Flexible container 3: First filter element 4: Second filter element 5: Blood outlet 6: First seal area 7: Second seal area 8: Flexible frame

Claims (4)

An inlet side container having a blood inlet attached to a flexible sheet;
An outlet side container having a blood outlet attached to a flexible sheet;
It consists of a sheet-like filter element for removing microaggregates and leukocytes or microaggregates and leukocytes and platelets from blood,
In the blood processing filter in which the sheet-like filter element is sandwiched between the respective containers and is fixed to the respective containers at the periphery thereof, whereby the inside is partitioned into the inlet side space and the outlet side space.
A spacer having a thickness of 0.5 to 5 mm, a hole area ratio of 30 to 70%, and a total area including the hole area of 10 to 90% in terms of the effective filtration area between the sheet-like filter element and the outlet side container. The blood processing filter is characterized in that the spacer is not fixed to either the filter element or the respective containers at the peripheral edge of the sheet-like filter element.   The blood processing filter according to claim 1, wherein the spacer covers a surface obtained by shrinking the effective filtration surface shape by 1/16 about the center of gravity of the effective filtration surface.   The blood processing filter according to claim 1 or 2, wherein a part of the peripheral portion of the spacer and the outlet side flexible container are joined at a portion other than the fixing portion of the filter element.   The blood processing filter according to any one of claims 1 to 3, wherein a material of the spacer is the same as that of the flexible container.