JPH0852471A - Water purifier and its production - Google Patents

Abstract

PURPOSE:To provide a water purifier using a hydrophobic film without accompanying eluting components. CONSTITUTION:This water purifier is produced by incorporating a hydrophilicity imparted film composed of a hydrophobic component and a physically insolubilized hydrophilic component, and a hydrophilicity imparted film obtained by introducing a hydrophilic component in the production process of a film using a hydrophobic polymer as a main base material and insolubilizing the hydrophilic component by radioactive rays and/or heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel water purifier and its manufacturing method.

[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,
An example in which it can be used immediately by fixing (for example, JP-A-61-120602 and JP-A-61-125).
405, JP-A-61-125408, JP-A-61-
No. 125409, JP-A-61-133102, JP-A-61-133105, etc.), but the adhesion of the hydrophilic polymer is insufficient and hydrophilic components are eluted from the membrane during use. There are problems such as.

[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 insoluble in water 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 the hydrophobic membrane can be used as an instant water purifier without the elution component.

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, and the like, but 50 ° C or higher and 200 ° C or lower are 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. As the film-forming step of introducing the hydrophilic component, block copolymerization into the film material, mixing into the film-forming raw solution, post-treatment after forming the hydrophobic film, etc.
Although any stage may be used, it is advantageous in that it is easy to secure large pores by mixing in the stock solution for membrane formation or introduction by post-treatment, and it is possible to reduce the amount of the hydrophilic component used. 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 permeation performance was measured by a method of applying water pressure to the inside of the hollow fiber while maintaining the temperature at 37 ° C., and calculating from the amount of water permeating to the outside through the membrane for a certain time, the effective membrane area, and the transmembrane pressure difference.

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.

[0015]

【Example】

Example 1 A hollow fiber membrane made of polypropylene (water permeability 6700 ml /
An aqueous solution of 0.15% collagen was dipped and impregnated in hr · mmHg · m ² (hereinafter the same unit), and UV irradiation was performed for 2 hours using a 15W sterilizing lamp at a distance of 10 cm in a nitrogen atmosphere. After the membrane was dried, the water permeability was measured and a value of 2500 was obtained.

Example 2 A hollow fiber membrane made of polyethylene (water permeability of 5000) was dipped and impregnated with a 20% aqueous solution of polyethylene glycol (# 20000) and irradiated with γ-rays at 2.5 Mrad. When the water permeability was measured after drying the film, a value of 3200 was obtained.

Example 3 A flat membrane (water permeability 2300) made of polyacrylonitrile (molecular weight 158,000) was dipped and impregnated in the same manner as in Example 1, and this time, one surface was irradiated with ultraviolet rays for 1 hour each. When the water permeability was measured after drying the film, a value of 1850 was obtained.

Comparative Examples 1 to 3 Example 1, except that the irradiation of ultraviolet rays or γ rays was omitted.
After repeating steps 2 and 3 and drying, the water permeability was measured to be substantially zero.

Example 4 15 parts of polysulfone (Udel Polysulfone P-3500),
A hollow fiber membrane formed from an undiluted solution consisting of 8 parts of polyvinylpyrrolidone (K-90), 75 parts of dimethylacetamide and 2 parts of water is dry-heat treated at 185 ° C for 1.5 hours to insolubilize polyvinylpyrrolidone in water. Was applied. When the water permeability of this completely dry film was measured, a value of 15000 was obtained. Since the surface of this membrane has pores of about 0.2 μm and has good water wettability under normal pressure, it can be used as a water purifier.

Example 5 A hollow fiber membrane produced in the same manner as in Example 4 was modularized, filled with water, and post-treated with 2.5 Mrad γ-ray irradiation. After drying this membrane, the water permeability was measured to be 1
A performance of 1000 was obtained.

Example 6 When the hollow fiber membranes of Examples 1 to 5 were subjected to an eluate test, the absorbances at 220 nm to 350 nm were all 0.1 or less.

[0022]

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

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Claims (2)

[Claims] 1. A water purifier comprising a hydrophilization film comprising a hydrophobic component and a hydrophilic component which is physically insolubilized. 2. A hydrophilic membrane incorporated with a hydrophilic component in the process of producing a membrane mainly composed of a hydrophobic polymer, and the hydrophilic component being water-insolubilized by radiation or / and heat. Water purifier manufacturing method.