JPH0852331A - Plasma collecting membrane and production thereof - Google Patents

Abstract

PURPOSE:To instantly enable the use of a hydrophobic membrane as a plasma collecting membrane by introducing a hydrophilic component made water- insoluble by radiation during a process for producing a membrane based on a hydrophobic polymer. CONSTITUTION:A hydrophobic membrane is produced by using a hydrophobic polymer such as polyethylene or polypropylene as a main material. In this membrane manufacturing process, a hydrophilic component such as vinyl pyrrolidone or vinyl alcohol is introduced into a membrane forming raw soln. This hydrophilic component is insolubilized by radiation such as gamma-rays and/or heat. By this constitution, a plasma collecting membrane using an instantly usable hydrophobia membrane is obtained without being accompanied by an elution component.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel plasma collection membrane and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, water treatment membranes used in filtration and dialysis treatments use a water-soluble membrane permeability maintaining agent such as glycerin, a hydrophilic polymer as a membrane material, and water. It has been supplied in a coexisting state.
However, with, it is necessary to wash and remove the membrane permeability maintaining agent before use, and it is not possible to use immediately, and with that, the pore size is generally small, and it is difficult to form a membrane that can be used for separating components having a molecular weight of tens of thousands or more. For example, when the liquid to be treated is blood, there are applications in which coexisting water needs to be replaced in advance with a liquid that does not deteriorate the liquid to be treated, and there are problems in that it cannot be used immediately.

On the other hand, as film materials, polyethylene, polypropylene, polycarbonate, polyacrylonitrile, polysulfone, polyester, poly (vinylidene difluoride), poly (tetrafluoroethylene), polymethylmethacrylate,
Membranes mainly composed of hydrophobic polymers such as cellulose triacetate are provided as filtration membranes and dialysis membranes, but these hydrophobic membranes can immediately exhibit their original permeability unless they are left in a bald state. Therefore, the problem that the hydrophobic membrane cannot be used immediately has been destined for the hydrophobic membrane. Also, by introducing a hydrophilic component into the hydrophobic membrane,
Examples of enabling immediate use by fixing (for example, JP-A-61-120602 and JP-A-61-1254)
05, JP-A-61-125408, JP-A-61-125
409, JP-A-61-133102, JP-A-61-13
3105), but these have a problem that the hydrophilic polymer is not firmly fixed and the hydrophilic component is eluted from the membrane during use.

[0004]

In view of the above situation, the inventors of the present invention have made extensive studies as to how to immediately use the hydrophobic membrane without the eluting component. The invention was reached.

[0005]

[Means for Solving the Problems] That is, by introducing a hydrophilic component, which is water-insoluble by radiation or / and heat in the manufacturing process of the membrane, into a hydrophobic membrane mainly made of a hydrophobic polymer, It has been found that a hydrophobic membrane can be used as an immediate blood plasma membrane without elutable components.

The hydrophobic membrane material to which the present means can be applied is not particularly limited, but polyethylene, polypropylene, polycarbonate, polyacrylonitrile, polysulfone, polyester, poly (vinylidene difluoride), poly (tetrafluoroethylene), polymethylmethacrylate. , Cellulose triacetate, polystyrene, polyethyl acrylate, polyvinyl acetate, polyvinyl chloride, etc., and derivatives thereof, or copolymers between the constituent monomers of these polymers, and further mainly these copolymerization components. Examples of the polymer include a polymer containing a small amount of a hydrophilic component, and this means is a water absorption rate measured by leaving it at equilibrium water absorption rate (20 ° C., relative humidity 65% for 1 week, water weight / polymer weight%). The displayed value) is 5% or less, more preferably 2
Applicable to less than% material.

There are a method of irradiating with radiation and a method of heating as a means for insolubilizing a hydrophilic polymer in water. In the former, the resistance mainly composed of polyethylene, polysulfone, polystyrene, polyester, polyethyl acrylate, polyvinyl acetate, etc. The latter is preferably used for materials having excellent radiation resistance, and the latter is preferably used for materials having excellent heat resistance mainly composed of polycarbonate, polysulfone, poly (vinylidene difluoride), poly (tetrafluoroethylene), polyester and the like. Furthermore, for materials having both excellent radiation resistance and heat resistance such as polysulfone and polyester, it is possible to use both means in combination.

As the hydrophilic component which becomes insoluble in water by radiation, vinylpyrrolidone, hydroxyethyl methacrylate, vinyl alcohol, ethylene glycol, methoxy polyethylene glycol methacrylate and the like, and monomers, oligomers, polymers and copolymers of these derivatives, Alternatively, proteins such as peptide, albumin and collagen may be used. As the hydrophilic component which is insoluble in water by heat, vinylpyrrolidone, ε-caprolactam, vinyl alcohol, ethylene oxide, hydroxyethyl methacrylate and the like, and monomers, oligomers, polymers of these derivatives, and copolymers between them, or peptides, Examples thereof include proteins such as albumin and collagen.

Gamma rays, ultraviolet rays, electron beams, etc. are used as the radiation as the water insolubilizing means. Especially, since the gamma rays have high penetrability, not only a single membrane but also a membrane aggregate or a membrane is incorporated. It is preferably used because the hydrophilic component can be treated to insolubilize water even in a module state. As the heating means as the water insolubilizing means, any of dry heat, wet heat and hot bath heating can be used. As the heating temperature, it is necessary to consider the softening point and melting point of the hydrophobic material, the thermal decomposition temperature of the hydrophilic component, etc., but 50 ° C. to 200 ° C. is preferable. Further, the heat treatment can be used not only as a means for making the hydrophilic component insoluble in water, but also as a means that also serves as a means for adjusting the pore size.

The film-forming step of introducing the hydrophilic component is as follows:
At any stage, such as block copolymerization into the membrane material, incorporation into the membrane forming stock solution, post-treatment after formation of the hydrophobic membrane,
It is advantageous in that it is easy to secure large pores when it is mixed into the membrane forming solution or introduced by post-treatment, and the amount of hydrophilic component used can be reduced. Further, the irradiation of radiation and the heat treatment may also serve as a sterilizing means for the membrane or the module incorporating the membrane.

The form of the membrane in the present invention is not particularly limited, and examples thereof include a sheet-shaped, hollow fiber-shaped, and microcapsule-shaped membrane.

The effectiveness of the present invention will be described below with reference to examples. The measuring method used there is as follows.

(1) Water-permeable In the case of a hollow fiber membrane, the hollow fiber membrane is inserted into a glass case having holes for reflux liquid at both ends, and a small module is prepared using a commercially available potting agent. The water permeability was measured by a method in which the water pressure was applied to the inside of the hollow fiber while maintaining the temperature at 37 ° C., and the amount of water permeating to the outside through the membrane for a certain period of time, the effective membrane area, and the transmembrane pressure difference were used to calculate.

In the case of a flat membrane, the same measurement was carried out using a stirring cylindrical cell.

(2) Eluate A test solution is prepared by heating 0.5 g of the membrane with 50 cc of hot water at 70 ° C. for 1 hour. The absorbance of the test solution at a wavelength of 220 to 350 μm is measured. The dialysis-type artificial kidney device approval standard sets the standard under this condition to 0.1 or less.

[0016]

【Example】

Example 1 15 parts of polysulfone (Udel Polysulfone P-3500),
A hollow fiber membrane formed from an undiluted solution containing 8 parts of polyvinylpyrrolidone (K-90), 75 parts of dimethylacetamide and 2 parts of water was dried at 170 ° C. for 5 hours to form a hydrophilic film. The hollow fiber membranes were bundled to have a membrane area of 0.15 m ² , modularized, dried with 2.5 Mrad γ-ray irradiation, and dried to obtain a dry membrane with bovine blood (hematocrit value 40%, total protein concentration 65 g / dl). When the plasma separation performance was measured, the temperature was 3
Performance of plasma filtration flow rate of 16 ml / min was obtained at 7 ° C., transmembrane pressure difference of 47 mmHg, and blood flow rate of 50 ml / min. Since there is no water, the performance as an excellent dry plasma membrane with protein permeability (concentration in filtrate / concentration in blood) exceeding 95% was recognized from the initial stage.

Example 2 When the hollow fiber membrane of Example 1 was subjected to an eluate test, the absorbances at 220 nm to 350 nm were all 0.1 or less.

[0018]

EFFECTS OF THE INVENTION According to the present invention, without any elutable component,
A plasma collection membrane using a hydrophobic membrane can be provided.

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Claims (2)

[Claims] 1. A plasma collection membrane comprising a hydrophobic component and a physically insolubilized hydrophilic component. 2. A method for producing a plasma-collecting membrane, which comprises introducing a hydrophilic component in a process for producing a membrane containing a hydrophobic polymer as a main material and insolubilizing the hydrophilic component with radiation or / and heat. .