JP2002263420A - Method for producing leukocyte selective removal filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a leukocyte selective removal filter which selectively removes only leukocytes from whole blood. SOLUTION: In the method for producing a leukocyte selective removal filter for whole blood processing, a polymer solution comprising a polymer containing an unreacted monomer and a low molecular weight polymer and one or more solvents is subjected to liquid-liquid phase separation by a heat induced phase separation method and/or a nonsolvent induced phase separation method to obtain a polymer concentrated phase solution and a polymer diluted phase solution. The polymer concentrated phase solution is recovered and diluted with a solvent and a filter substrate is coated with the resulting solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a leukocyte selective removal filter for selectively removing leukocytes from whole blood. Particularly, manufacture of a leukocyte selective removal filter for selectively and efficiently removing leukocytes from a whole blood product containing erythrocytes, platelets, plasma components and leukocytes while minimizing loss of erythrocytes, platelets and plasma components. About the method.

[0002]

2. Description of the Related Art In the field of blood transfusion, platelet transfusion aimed at improving the bleeding tendency of patients occupies an important position. Can cause a life crisis. For example, leukocytes produce vasoconstrictor agents such as pradikinin, eliciting an acute fever response and an associated hypotensive response. Lymphocytes also transmit infectious agents such as cytomegalovirus and HTLV-1. Therefore, it is necessary to remove leukocytes from platelet preparations to a sufficiently low level to prevent these side effects.

[0003] Therefore, as a means for selectively removing leukocytes, a centrifugal separation method or a method using a filter having adsorptivity to leukocytes has been implemented. Methods for removing leukocytes from whole blood include centrifugal methods, dextran methods, filter methods and washing methods, and the filter method for adsorbing and removing leukocytes has excellent leukocyte removal ability and is easy to operate. It is widely used because it has advantages such as low cost and low cost.

It is considered that the main mechanism of the leukocyte removal by the filter method is adsorption removal using the leukocyte adsorption ability. In Japanese Patent Application Laid-Open No. 3-158168, it has been found that the concentration of leukocytes passing through the fiber laminate decreases exponentially with respect to the thickness of the fiber laminate. This suggests that the fibers are adsorbed with a certain probability each time they come in contact with the vicinity of the inter-woven points of the fibers when they flow, supporting the above-mentioned theory of adsorption removal. Therefore, the study of high performance in the conventional leukocyte removal filter is to increase the frequency of contact between the fibers and leukocytes, that is, to reduce the average fiber diameter, increase the packing density, or improve the uniform fiber diameter distribution. Using a nonwoven fabric having
No. 3909), and few focused on the chemical properties of the surface of the nonwoven fabric.

As a few other examples of studies focused on the chemical properties of the surface of a nonwoven fabric, Japanese Patent Application Laid-Open No. 1-249063 and Japanese Patent Publication No.
02094 and the like, the former is the purpose of surface modification to improve the platelet passage rate, and the latter is to impart hydrophilicity to facilitate priming with blood. The aim is not to increase the probability of leukocyte adsorption.

[0006] WO 87/05812 discloses that
As a result of research aimed at obtaining a filter having a high platelet passage rate and excellent leukocyte removal ability, the nonwoven fabric was coated with an appropriate amount of a polymer containing a basic functional group and a nonionic hydrophilic group. In the Examples, it is disclosed that the method has excellent leukocyte removing ability and enhances platelet permeability, and that using a polymer containing more basic functional groups increases the removal rate of both platelets and leukocytes. It is described in. Given that cell surfaces generally have a negative charge, polymers with basic functional groups increase leukocyte rejection due to the positively charged basic functional groups under physiological conditions. This is considered to be due to the ionic binding force acting between the negative charge on the cell surface and this is considered to be a very reasonable result. The publication describes an experiment using a leukocyte selective removal filter for bovine blood treatment.However, a filter having a higher platelet passage rate for human whole blood treatment and excellent leukocyte selective removal ability is demanded. I have.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a leukocyte selective removal filter for selectively removing only leukocytes from whole blood. Examples of the leukocyte selective removal filter include whole blood processing, platelet preparation processing, erythrocyte preparation processing, etc., and the present invention includes whole blood processing, particularly, erythrocytes, platelets, plasma components and leukocytes. An object of the present invention is to provide a method for producing a leukocyte selective removal filter for selectively and efficiently removing leukocytes while suppressing loss of red blood cells, platelets, and plasma components from a whole blood product extremely small.

[0008]

Means for Solving the Problems The present invention has solved the above-mentioned problems, and it is an object of the present invention to provide a filter for selectively removing leukocytes in which a polymer is coated on a filter substrate as described in the above-mentioned WO 87/05812. The present inventors have found that a low polymer and a residual monomer contained in a polymer inhibit a platelet passage rate in human blood treatment, and have reached the present invention. That is, the present invention
(1) A polymer solution comprising a polymer containing an unreacted monomer and a low polymer and one or more solvents is subjected to a heat-induced phase separation method and / or a non-solvent-induced phase separation method to form a polymer rich phase solution and a polymer dilute phase solution. After the liquid-liquid phase separation, a method for producing a leukocyte selective removal filter for whole blood treatment, characterized in that the separated and concentrated polymer concentrated phase solution is diluted with a solvent and then coated on a filter substrate,
(2) The method for producing a filter for selectively removing leukocytes for whole blood treatment according to the above (1), wherein the polymer is further immersed in a non-solvent after coating, and (3) the polymer comprises a nonionic hydrophilic group and a base. The present invention relates to the method for producing a leukocyte selective removal filter for treating whole blood according to the above (1) or (3), which is a polymer having a functional nitrogen-containing functional group.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a filter for selectively removing leukocytes for treating whole blood according to the present invention will be described in detail. The production method of the present invention is a very effective method for efficiently producing a leukocyte selective removal filter having excellent platelet passage performance and excellent leukocyte removal performance from whole blood containing both platelets and leukocytes. It is. for that purpose,
First, a polymer solution comprising a polymer containing an unreacted monomer and a low polymer and one or more solvents is converted into a polymer concentrated phase solution and a polymer dilute phase solution by a thermally induced phase separation method and / or a non-solvent induced phase separation method. After the liquid-liquid phase separation, it is necessary to dilute the separated polymer concentrated phase solution with a solvent and then coat it on a filter substrate.

A polymer solution comprising an unreacted monomer and a polymer containing a low polymer and one or more solvents is subjected to a heat-induced phase separation method and / or a non-solvent-induced phase separation method to form a polymer concentrated phase solution (of which a high Unreacted by liquid-liquid phase separation into a polymer solution with low molecular weight and low molecular weight distribution (polymer solution with low molecular weight distribution) and a polymer dilute phase solution (polymer solution with high monomer and low molecular weight with low molecular weight distribution) It is possible to obtain a polymer concentrated phase solution having a low content of monomer and low polymer, and in the present invention, after diluting the polymer concentrated phase solution with a solvent, coating the filter base material with leukocyte removal performance. An unexpected effect that an excellent leukocyte selective removal filter can be obtained can be obtained. The polymer concentrated phase solution is used as a solution (hereinafter, also simply referred to as “polymer coat solution”) diluted to a desired concentration using a solvent because of its high concentration and high viscosity.

In the present invention, the term "low polymer" refers to a polymer having a peak top molecular weight in a molecular weight curve (refer to FIG. 1) measured by gel permeation chromatography (GPC) of the polymer, ie, 1/4 or less of a molecular weight having a maximum intensity. Dimers, trimers, oligomers and polymers having a molecular weight of In the molecular weight distribution curve, the content of the low polymer having a molecular weight of 1/4 or less with respect to the peak top molecular weight is 1/1 with respect to the peak top molecular weight when the peak area in the molecular weight curve shown in FIG. It means the ratio of the peak area portion of 4 or less. The method of obtaining the molecular weight curve (method of measuring the molecular weight distribution) will be described later.

In FIG. 1, the horizontal axis represents the molecular weight, and the vertical axis represents the RI (intensity measured by a differential refractometer).

When the polymer solution is separated in a liquid-liquid phase in a certain container and left for a certain period of time, the polymer solution is phase-separated into a complete two-phase solution (see FIG. 2). Since the polymer concentrated phase solution having a higher specific gravity becomes the lower solution, it is possible to separate and collect the polymer concentrated phase solution by removing the polymer diluted phase solution on the upper side or extracting only the polymer concentrated phase solution. . The liquid-liquid phase separation referred to in the present invention is to separate a polymer solution uniformly dissolved at a certain temperature into two-phase solutions having different polymer concentrations and molecular weight distributions (a polymer concentrated phase solution and a polymer dilute phase solution). Good, and does not include a phase change in which a solid or solid polymer precipitates.

In the present invention, the thermally induced phase separation method (Therm)
all Induced Phase Separa
The term “tion method” means that a polymer solution, which is uniformly dissolved at a certain temperature, is cooled or heated at a constant rate to form the polymer solution into a plurality of phases (for example, a liquid phase and a liquid phase, or a liquid phase and a solid phase). Or a liquid phase, a liquid phase and a solid phase). Among them, in the present invention, only a phase change that is divided into a liquid phase and a liquid phase is used.

The temperature or temperature gradient of cooling or heating varies depending on the type of the polymer to be purified. For example, 2-hydroxyethyl (meta) containing a hydroxyl group as a nonionic hydrophilic group and an amino group as a basic nitrogen-containing functional group is used. A) a copolymer composed of 97 mol% of acrylate and 3 mol% of dimethylaminoethyl (meth) acrylate, or 2-hydroxyethyl (meth) acrylate 95
Mole% and diethylaminoethyl (meth) acrylate 5
When it is a copolymer consisting of mol%, liquid-liquid phase separation is possible by leaving the polymer solution dissolved at 40 ° C to 60 ° C to be cooled to room temperature (25 ° C) or lower. For details of the thermally induced phase separation method, see "Membrane Technology (2nd Edition)" (Marcel
Mulder, translation of Masakazu Yoshikawa et al., IPC Corporation.

The non-solvent induced phase separation method (Non-solvent-induced phase separation) according to the present invention
solvent InducedPhase Sepa
A ratio method is a method in which a non-solvent of a polymer is added to a polymer solution that is uniformly dissolved at a certain temperature to form the polymer solution into a plurality of phases (for example, a liquid phase and a liquid phase, or a liquid phase and a solid phase, Or a liquid phase, a liquid phase and a solid phase). Among them, in the present invention, only a phase change that is divided into a liquid phase and a liquid phase is used.

In the method of the present invention, a thermally induced phase separation method and / or
Alternatively, the content of the low polymer contained in the polymer purified by the non-solvent induced phase separation method needs to be 20% or less. When it exceeds 20%, it is difficult to obtain a leukocyte selective removal filter satisfying both the leukocyte removal rate and the platelet passage rate.

In addition, when a reprecipitation method or a fractionation method, which is conventionally known as a method for removing a low polymer from a high polymer, is not more than 1/4 of a peak top molecular weight in a molecular weight curve. 20 low polymers
% Is difficult.

The polymer solution used in the present invention comprises at least a polymer and one or more solvents. The polymer used in the present invention swells in water, but is not particularly limited as long as it does not dissolve in water.Sulfonate, carboxyl, carbonyl, amino, amide, cyano, hydroxyl Group,
Methoxy group, phosphate group, oxyethylene group, imino group,
Polymers having one or more of imide groups, imino ether groups, pyridine groups, pyrrolidone groups, imidazole groups, quaternary ammonium groups and the like can be exemplified.

Among them, when used as a filter material for the selective removal of leukocytes for whole blood treatment, a copolymer having a nonionic hydrophilic group is preferred in terms of non-adsorbed platelets, and a nonionic hydrophilic group and a basic nitrogen-containing functional group are further preferred. Is more preferable because it has a selective adsorption property of having a platelet non-adsorbing property and a leukocyte removing property.

In the present invention, examples of the nonionic hydrophilic group include a hydroxyl group, an ether group, an ester group and an amide group. As the monomer containing a nonionic hydrophilic group, a monomer containing the above-mentioned hydroxyl group and amide group, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, vinyl alcohol (after polymerization as vinyl acetate, Hydrolysis), (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-vinylpyrrolidone and the like. Examples of the monomer containing an ether group as a nonionic hydrophilic group include methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and methoxytetraethylene glycol (meth) acrylate. Alkoxy polyethylene glycol (meth) acrylates and the like can be mentioned.

The basic nitrogen-containing functional groups include nitrogen-containing aromatic groups such as primary amino group, secondary amino group, tertiary amino group, quaternary ammonium group, pyridine group and imidazole group. Is mentioned. Examples of the monomer having a basic nitrogen-containing functional group include allylamine; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, 3-dimethylamino-2-hydroxyl (meth) acrylate, and the like. (Meth) acrylic acid derivative; p (para) -dimethylaminomethylstyrene, p-
Styrene derivatives such as dimethylaminoethylstyrene; 2
Vinyl derivatives of nitrogen-containing aromatic compounds such as -vinylpyridine, 4-vinylpyridine and 4-vinylimidazole; and derivatives in which the above-mentioned vinyl compounds have been converted into quaternary ammonium salts by alkyl halide or the like.

As a method of coating the polymer substrate with the polymer coating solution, a post-metering method of coating the filter substrate in excess of a desired coating amount and then reducing the coating amount to a specified coating amount, and a filter substrate There is a pre-measurement method of transferring a polymer coat solution, which has been measured so as to have a desired coating amount to a filter substrate before coating on a filter substrate, but any method may be used.

Furthermore, in the present invention, the polymer coating solution is coated on the filter substrate and then nip, so that the polymer coating solution can be uniformly coated in the thickness direction of the filter substrate. It is possible to further improve. The nip referred to in the present invention refers to squeezing out excess polymer coating solution and residual solvent contained in the filter substrate after coating with the polymer coating solution. A method of passing between two rolls can be exemplified.
In addition, it is possible to uniformly disperse the polymer coat solution in the thickness direction of the filter substrate by nipping the polymer coat solution after coating. The size of the gap between the nip rolls is not more than the thickness of the filter substrate and should not damage the filter substrate. If the porosity of the filter substrate is 50% to 95%, the thickness of the filter substrate may be reduced. Preferably, it is 0.10 times to 1.00 times. If the size of the gap is less than 0.10 times, the filter substrate is easily damaged, and if it is more than 1.00 times, the obtained filter tends to have a lower platelet passage rate.

The solvent used for dissolving the polymer includes, for example, glycols such as ethylene glycol and diethylene glycol when the polymer is a copolymer of 2-hydroxyethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate; , Ethanol, n (normal) -propyl alcohol, isopropyl alcohol, n-butyl alcohol, iso-butyl alcohol, t (tertiary) -butyl alcohol, and the like; N, N-dimethylformamide, methylcellosolve and the like. be able to.

The solvent that induces the thermally induced phase separation method varies depending on the polymer to be purified, but a single solvent system or a mixed solvent system can be used. In some cases, it is difficult to find a suitable solvent in a single system, or in some cases, it is preferable to use a mixed solvent in terms of cost. The solvent will be described with specific examples. For example, if the polymer is a copolymer of 2-hydroxyethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate, ethanol, iso-propyl alcohol, etc. And a mixed solvent system in which an appropriate amount of water is added thereto. The non-solvent for the polymer is, for example, water if the polymer is a copolymer composed of 2-hydroxyethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate;
-Hexane, n-heptane; toluene, xylene; aliphatic hydrocarbons such as ketones such as acetone and methyl ethyl ketone; salts; alkalis; liquids or solids which do not dissolve polymers such as acids but are compatible with solvents are used. Can be The combination of a solvent and a non-solvent that induces liquid-liquid phase separation is, for example, ethanol (solvent) if the polymer is a copolymer of 2-hydroxyethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate. And water (non-solvent), ethanol (solvent) and n-hexane (non-solvent).

In the non-solvent-induced phase separation method of the present invention, the amount of the non-solvent added to the polymer solution is 2
-If a non-solvent composed of a copolymer of hydroxyethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate and ethanol (solvent) is water or hexane, the polymer solution is 2.5 to 4.0 ( volume)
Twice the amount of non-solvent is used.

The concentration of the polymer in the polymer solution is not particularly limited because it varies depending on the kind and molecular weight of the polymer used, but it is 0.1% by weight to 70% by weight, preferably 1% by weight.
% To 60% by weight, more preferably 5% to 50% by weight. When the polymer concentration is less than 0.1% by weight, the efficiency of recovery of the polymer at the time of purification is poor, so that it is not efficient. It is in. Also, by controlling the solution viscosity and the dissolution state, the molecular weight distribution in the polymer rich phase solution and the polymer dilute phase solution can be controlled, so for the purpose of controlling the solution viscosity and the dissolution state,
Compatible with solvents such as water, salts, alkalis and acids,
It is also possible to add a plurality of non-solvents that do not dissolve the polymer, and the type and amount of the non-solvent may be optionally determined depending on the combination.

When the polymer is a polymer having a nonionic hydrophilic group and a basic nitrogen-containing functional group, the platelet passage rate can be further improved by immersing the polymer in a nonsolvent. The detailed mechanism of the improvement of the platelet passage rate by immersion in a non-solvent is unknown, but when the molecular orientation of the filter surface changes or the filter substrate surface is modified by polymer coating, the polymer substrate It is conceivable to improve the coverage of the steel.

The temperature for immersion in a non-solvent is 20 ° C. to 1 ° C.
It is suitable to carry out at 20C, more preferably at 40C to 110C, even more preferably at 50C to less than 100C. If the temperature of the non-solvent is lower than 20 ° C., the improvement in the platelet passage rate is reduced, which is not preferable. This is not preferred because the risk of The immersion time in the non-solvent is 10 seconds to 60 seconds.
Minutes, preferably 1 minute to 40 minutes, more preferably 3 minutes to 3 minutes.
0 minutes. If the treatment time is shorter than 10 seconds, the platelet passage rate is not improved, and if the treatment time is longer than 60 minutes, not only the productivity is reduced, but also the polymer coating layer is liable to fall off. Is undesirably reduced.

The filter substrate used in the production of the filter for selectively removing leukocytes for whole blood treatment of the present invention includes:
In addition to the nonwoven fabric produced by the melt blowing method, the flash spinning method or the papermaking method, any form of a known filter material such as paper, woven fabric, mesh and a polymer porous body may be used. This is a particularly preferred form. Here, the nonwoven fabric refers to a cloth-like material in which an aggregate of fibers or yarns is chemically, thermally, or mechanically connected irrespective of knitting or weaving. Fiber materials include polyamide, aromatic polyamide, polyester, polyacrylonitrile, polytrifluorochloroethylene, polystyrene, polymethyl (meth) acrylate, polyethylene,
Examples thereof include synthetic fibers such as polypropylene and poly-4-methylpentene, and regenerated fibers such as cellulose and cellulose acetate.

In the case of a filter substrate comprising a nonwoven fabric and a woven fabric, the average fiber diameter is 0.3 μm to 10 μm,
Preferably it is 0.3 μm to 3 μm, more preferably 0.1 μm.
It is 5 μm to 1.8 μm. Average fiber diameter is 0.3μm
If it is less than 10 μm, the pressure loss at the time of filtering whole blood or the like may be impractical. If it exceeds 10 μm, the probability of contact between fibers and leukocytes is too low. There is a possibility that the removal component may not be sufficiently exhibited. Here, the average fiber diameter is an average diameter obtained by sampling a part of a non-woven fabric or a woven fabric constituting a filter and measuring the result by an electron micrograph.

The porosity of the filter substrate made of a nonwoven fabric and a woven fabric is preferably 50% or more and less than 95%.
More preferably, it is 70% or more and less than 90%. If the porosity is less than 50%, the flow of a leukocyte-containing or platelet-containing liquid such as blood is poor, and if it is 95% or more, the mechanical strength of the filter substrate is weak, which is not suitable. The porosity is measured by measuring the dry weight (W1) of the filter substrate cut into a predetermined area, and measuring the thickness to calculate the volume (V).
This filter substrate is immersed in pure water, degassed, and the weight (W2) of the water-containing filter substrate is measured. From these values, the porosity is determined by the following calculation formula.
Note that ρ in the following formula is the density of pure water. Porosity (%) = (W2−W1) × 100 / ρ / V

As the polymer porous body, polyethylene,
Polypropylene, poly-4-methylpentene, polyvinyl formal, polyacrylonitrile, polysulfone,
Examples include porous materials such as cellulose, cellulose acetate, polyurethane, polyvinyl acetal, polyester, polyamide, polyetherimide, poly (meth) acrylate, polyvinylidene fluoride, and polyimide. The porous polymer has an average pore diameter of 1 μm or more.
It is 60 μm, preferably 1 μm to 30 μm, more preferably 1 μm to 20 μm. If it is less than 1 μm, the flow of a leukocyte and platelet-containing liquid such as blood is poor, and if it exceeds 60 μm, the probability of contact between the porous body and the leukocytes is too low, and the leukocyte removal rate becomes low, which is not preferable. The average pore diameter as used herein means POROFIL (COUL) according to the air flow method described in ASTM F316-86.
TER ELECTRONICS LTD.) Indicates an average pore diameter measured in a liquid.

When the filter substrate is a woven or non-woven fabric, it may be used alone depending on the thickness thereof,
A plurality of sheets may be used. The number of sheets to be overlapped depends on the blood filtration conditions and is not critical, but usually several to several tens of sheets are used.

Examples of the present invention will be described below, but the present invention is not limited to these examples. The molecular weight distribution and the average molecular weight of the polymer are set to 1 mmol / L (liter) in N, N-dimethylformamide so that LiBr is obtained.
Gel permeation chromatography (GPC) in which a solution prepared by dissolving a polymer in a solution (hereinafter referred to as "solution A") to which (lithium bromide) is added (a main body: HLC-8020 + manufactured by Tosoh Corporation): GPC: LALLS ver. 2.03), and measured at 40 ° C. by RI (differential refractometer).
The column is a guard column (TSK g, manufactured by Tosoh Corporation).
ardcolum HXL-H) and this column (pre-column: TSKgel GMHXL manufactured by Tosoh Corporation)
B0032, second stage column: TSKge manufactured by Tosoh Corporation
lα-M B0011). The use conditions (measurement conditions) were as follows: mobile phase (developing solution): solution A, FLOW Rate: 1 mL / min, column temperature: 4
Performed at 0 ° C. For calculating the molecular weight distribution and the average molecular weight of the polymer, the known molecular weight of polymethyl methacrylate (MM-10 set) manufactured by Polymer Laboratory and the GPC measurement value (Ret) of the polymethyl methacrylate were used.
Ention Time) was used.

[0036]

Example 1 (Preparation of Polymer Coating Solution) Copolymer of 97 mol% of 2-hydroxyethyl (meth) acrylate and 3 mol% of dimethylaminoethyl (meth) acrylate (weight average molecular weight 570,000, basic nitrogen Atom content 0.32 wt%, nonionic hydrophilic group 97 mol%, basic nitrogen atom amount 3 mol%, peak top molecular weight 3.75 × 10 ⁵ , low polymer content 26.0%) A four-fold volume of ethanol was added to the resulting polymerization solution (copolymer concentration 39% by weight, ethanol solution) and uniformly dissolved at 40 ° C. After leaving this solution at room temperature of 25 ° C. for 12 hours to separate the liquid-liquid phase by the thermally induced phase separation method,
Only the polymer concentrated phase solution (copolymer concentration 31% by weight) was separated and recovered. The obtained polymer concentrated phase solution had a content of basic nitrogen atoms of 0.32% by weight and a nonionic hydrophilic group of 9%.
7 mol%, basic nitrogen atom amount 3 mol%, peak top molecular weight 3.92 × 10 ⁵ , low polymer content 14.5%
It was confirmed that the 2-hydroxyethyl (meth) acrylate-dimethylaminoethyl (meth) acrylate copolymer was dissolved. Ethanol was added to the polymer concentrated phase solution and dissolved at a temperature of 40 ° C. to prepare a uniform polymer coat solution having a copolymer concentration of 8.15% by weight.

(Coating) Using a device shown in FIG. 3, a non-woven fabric made of polyethylene terephthalate fiber having an average fiber diameter of 1.2 μm (40 g / m ² basis weight, porosity 7
(9%, thickness 0.25 mm, density 0.16 g / cm ³ , width 300 mm) 30 m was continuously immersed in the above-mentioned solution at 40 ° C., and then passed between rolls having a gap of 0.13 mm to nip. did. Further, it passes through the first drying room at 40 ° C. (wind speed 15 m / sec) for 3 m, and passes through the second drying room at 60 ° C.
After passing through a drying room (wind speed: 15 m / sec) for 3 m, the film was wound up. The line speed was fixed at 3 m / min. The residual ethanol amount immediately after passing through the first drying chamber was 11%. Further, the amount of residual ethanol at the time of winding was 1% or less, and the filters did not adhere to each other after winding, so that efficient production was possible.

(Evaluation of Blood) An arbitrary part of the filter thus produced was cut into a 25 mm circular shape, and four pieces were set in a filter holder (manufactured by Shibata Scientific Instruments Factory Co., Ltd.). CPD as an anticoagulant
(Citrate-phosphate-dextro
6 mL of the human stored blood to which se) was added was flowed at room temperature at a constant rate of 2.7 mL / min using a syringe pump. Before and after passing through the filter, 1 mL of blood is collected, mixed with 9 mL of the leuco plate solution, centrifuged, the supernatant is discarded by decantation, and the leukocyte concentration in the adjusted 1 mL solution is measured using a hemocytometer. Thereby, leukocyte concentration was measured. In addition, the concentration of platelets in the blood can be measured using a multi-item automatic blood cell counter (SYSMEX K
-4500) stomalyzer (SYSMEX)
Was used as a hemolytic agent. The leukocyte removal rate and platelet passage rate were calculated by the following equations.

(Equation 1)

(Equation 2) The blood evaluation of this filter was performed 10 times and the average value is shown in Table 1. In whole blood filtration, a platelet passage rate of 80% or more was required, and high results were obtained in both leukocyte removal ability and platelet passage rate. No difference was observed in the hematocrit value in blood before and after filtration.

[0039]

Example 2 The same operation as in Example 1 was carried out except that fresh whole human blood (whole blood obtained by adding CPD for 3 hours after blood collection) was used in place of daily stored human blood. Table 1 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate.

[0040]

Example 3 The procedure was carried out except that a mixed solution of iso-propyl alcohol and pure water (iso-propyl alcohol: water = 1: 1 (volume ratio)) was used instead of ethanol used when preparing the polymer coating solution. The same operation as in Example 1 was performed. Table 1 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate.

[0041]

Example 4 The same operation as in Example 1 was carried out except that ethanol was added to the polymer concentrated phase solution used in Example 1 to use a polymer coat solution having a copolymer concentration of 5.96% by weight. Table 1 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate.

[0042]

EXAMPLE 5 Instead of the nonwoven fabric used in Example 1, a nonwoven fabric made of poly (trimethylene terephthalate) fiber having an average fiber diameter of 1.2 μm (40 g / m ² basis weight, porosity 7)
5%, a thickness of 0.23 mm, a density of 0.17 g / cm ³ , and a width of 300 mm). Table 1 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate.

[0043]

Example 6 2-Hydroxyethyl (meth) acrylate 95 was used in place of the polymer concentrated phase solution used in Example 1.
Mole% and diethylaminoethyl (meth) acrylate 5
Mole% copolymer (peak top molecular weight 4.08)
× 10 ⁵ , low polymer content 9.9%, basic nitrogen atom content 0.53% by weight, nonionic hydrophilic group 95 mol%,
The same operation as in Example 1 was performed except that a polymer concentrated phase solution (copolymer concentration: 30% by weight) consisting of a basic nitrogen atom (5 mol%) was used. Table 2 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate. Here, the peak top molecular weight of 4.08 ×
10 ^5, the low polymer content 9.9% of 2-hydroxyethyl (meth) acrylate - consists of diethylaminoethyl (meth) acrylate copolymer polymer-rich phase solution, 2-hydroxyethyl (meth) acrylate 95 mol % Copolymer and 5 mol% of diethylaminoethyl (meth) acrylate (weight average molecular weight 650,00
0, basic nitrogen atom content 0.53% by weight, nonionic hydrophilic group 95 mol%, basic nitrogen atom amount 5 mol%, peak top molecular weight 3.62 × 10 ⁵ , low polymer content 2
1.2%) in the same manner as in Example 1 using a polymerization solution (copolymer concentration 41% by weight, ethanol solution).

[0045]

Example 7 Instead of the polymer concentrated phase solution used in Example 1, the same chemical composition as in Example 1 having a peak top molecular weight of 3.82 × 10 ⁵ and a low polymer content of 12.4% was used. Copolymer (content of basic nitrogen atom 0.32% by weight,
Polymer concentrated phase solution (copolymer concentration 40 mol%) consisting of 97 mol% of nonionic hydrophilic groups and 3 mol% of basic nitrogen atoms
Wt%), except that the same operation as in Example 1 was performed. Table 2 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate. here,
A polymer concentrated phase solution comprising a 2-hydroxyethyl (meth) acrylate-dimethylaminoethyl (meth) acrylate copolymer having a peak top molecular weight of 3.82 × 10 ⁵ and a low polymer content of 12.4% was prepared in Examples. To the polymerization solution before purification used in 1 was added twice the volume of ethanol,
After uniformly dissolving at 40 ° C., 0.033 times the volume of n-hexane was added dropwise to the polymerization solution little by little with uniform stirring to separate the liquid and liquid phases by a non-solvent induced phase separation method. It was obtained by fractionally collecting only the polymer concentrated phase solution.

[0046]

Example 8 Instead of the polymer concentrated phase solution used in Example 1, the chemical composition is the same as that of Example 1 except that the peak top molecular weight is 3.80 × 10 ⁵ and the content of the low polymer is 18.9%. Copolymer (content of basic nitrogen atom 0.32% by weight,
A polymer concentrated phase solution (copolymer concentration 28%) consisting of 97% by mole of nonionic hydrophilic groups and 3% by mole of basic nitrogen atoms.
Wt%), except that the same operation as in Example 1 was performed. Table 2 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate. here,
A polymer concentrated phase solution comprising a 2-hydroxyethyl (meth) acrylate-dimethylaminoethyl (meth) acrylate copolymer having a peak top molecular weight of 3.80 × 10 ⁵ and a low polymer content of 18.9% was prepared in Examples. A heat-induced phase separation method in which a three-fold volume of pure water is added to the polymerization solution before purification used in 1 and uniformly dissolved at 40 ° C. and left at room temperature adjusted to 15 ° C. for 12 hours, It was obtained by separating and recovering only the polymer concentrated phase solution (copolymer concentration 28% by weight) by liquid-liquid phase separation by a combination of non-solvent induced phase separation methods.

[0047]

Example 9 The band-shaped coated filter obtained in Example 1 was bent at intervals of 1 m, and a mesh made of polypropylene was interposed therebetween to prevent the filters from adhering to each other. (Non-solvent for polymer for coating, pH 6.9) After immersion for 20 minutes, 40 ° C
Was dried at a wind speed of 15 m / sec for 3 hours in a hot air dryer.
The same blood evaluation as in Example 1 was performed using this filter. Table 2 shows the blood evaluation results at this time. High results were obtained in both leukocyte removal ability and platelet passage rate.

[0048]

Comparative Example 1 Instead of the polymer concentrated phase solution used in Example 1, the chemical composition was the same as that of Example 6 having a peak top molecular weight of 3.62 × 10 ⁵ and a low polymer content of 20.6%. Copolymer (content of basic nitrogen atom: 0.53% by weight,
The same operation as in Example 1 was performed except that 95 mol% of the nonionic hydrophilic group and 5 mol% of the basic nitrogen atom were used. Table 2 shows the blood evaluation results at this time. Here, the peak top molecular weight is 3.62 × 10 ⁵ , and the content of the low polymer is 2
0.6% of the 2-hydroxyethyl (meth) acrylate-dimethylaminoethyl (meth) acrylate copolymer was obtained by uniformly homogenizing the unpurified polymerization solution used in Example 6 in about 20 times the volume of pure water. The precipitate was purified by re-precipitation by dropwise addition and precipitation in small amounts while stirring, and the precipitate was further dried at 40 ° C. under vacuum.

【table 1】

[Table 2]

[0049]

As described above, the filter for selectively removing leukocytes for whole blood obtained by the production method of the present invention can selectively remove leukocytes from whole blood containing both platelets and leukocytes. It was found to have excellent performance in platelet passage rate and leukocyte removal performance. Therefore, the filter for selectively removing leukocytes for treating whole blood of the present invention can be used for medical applications, medical applications and general industrial applications.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a molecular weight distribution of a polymer used in a method for producing a filter of the present invention.

FIG. 2 is a diagram illustrating the concept of liquid-liquid phase separation of the present invention.

FIG. 3 is a front view showing an example of a manufacturing apparatus for manufacturing the leukocyte selective removal filter of the present invention.

[Explanation of symbols]

A homogeneous polymer solution B thermally induced phase separation (cooling or heating of polymer solution) or non-solvent induced phase separation (non-solvent added to polymer solution) C dilute polymer solution (homogeneous polymer solution) D polymer rich phase solution (Homogeneous polymer solution) 1 Filter substrate supply roll 2 Polymer solution coating tank 3 Polymer solution keeping constant temperature bath 4 Roll 5 Nip roll 6 Filter take-up roll 7 Filter substrate 8 Polymer solution 9 Impregnation roll 10 In constant temperature bath Temperature control water 11 Drying means (low temperature side) 12 Drying means (high temperature side)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C077 AA12 BB03 KK13 MM02 MM07 MM08 NN02 PP03 PP04 PP08 PP12 PP13 PP14 PP15 4D006 GA02 HA41 MA03 MA06 MA09 MB09 MC30X MC35X MC85 NA40 NA46 NA63 NA64 PB09 PB44 PB45 PC41 PCA BB08 BB10 BC13 CB04

Claims (3)

[Claims] A polymer solution comprising a polymer containing an unreacted monomer and a low polymer and one or more solvents is subjected to a thermally induced phase separation method and / or a non-solvent induced phase separation method to form a polymer rich phase solution and a polymer dilute phase. A method for producing a leukocyte selective removal filter for whole blood treatment, comprising separating a liquid-liquid phase into a solution, diluting the concentrated polymer solution separated and recovered with a solvent, and coating the filter base material. 2. The method according to claim 1, wherein the filter is further immersed in a non-solvent after coating. 3. The method according to claim 1, wherein the polymer is a polymer having a nonionic hydrophilic group and a basic nitrogen-containing functional group.