JPS60244303A - Composite and preparation thereof - Google Patents

Abstract

PURPOSE:To prepare a composite having a polymer membrane having fine pores uniformly formed thereto so as to communicate with both front and back surfaces thereof, by applying a solution of a membrane forming polymer in an org. solvent onto a support and drying the formed membrane in a specific atmosphere. CONSTITUTION:An org. solvent solution, which is prepared by dissolving a membrane forming polymer comprising a resinous substance such as polysulfone or polyvinyl chloride or rubbery substance such as butadiene rubber or nitrile rubber in an org. solvent such as polyethylene glycol is applied onto a support material such as a glass plate, a metal plate, paper or a plastic film by an immersion method, a spray method or a brush coating method. Directly after coating, the formed layer is dryed at 10-80 deg.C for 1-10min in an atmosphere with relative humidity of about 75-100%. By this method, a composite, wherein a polymer membrane having fine pores with the diameter of 0.1-10mum uniformly communicating with front and back surfaces thereof is formed onto a support, is obtained.

Description

[Detailed description of the invention] The present invention relates to a composite and a method for producing the same.

More specifically, the present invention relates to a composite that can be effectively used as an ion-exchange membrane, an ion-selective electrode, a biosensor, etc., and a method for producing the same.

For example, in order to increase the acid dialysis rate of ion exchange membranes, composite membranes in which thin ion exchange membranes are laminated on a porous support are used, but when attempting to manufacture such composite membranes, , fine pores may or may not be formed in the thin polymer film layer, making it impossible to obtain a certain composite film.As a result of various studies conducted by the present inventor to investigate the cause of this phenomenon, the present inventors found that: We learned that the air humidity during drying has a large influence on the coating of an organic solvent solution of a film-forming polymer onto a support, which is commonly used as a composite means, and the drying of the solution. It has been found that by maintaining humidity conditions within a certain range, micropores can be formed almost uniformly in the thin polymer film layer of the composite.

Therefore, the present invention relates to a composite body, which is formed by laminating a thin polymer film layer on a support in which fine pores communicating with both the front and back surfaces of the thin film are formed almost uniformly.

The present invention also relates to a method for producing such a composite, in which the composite is produced in an atmosphere with a relative humidity of about 75 to 100% after coating a solution of a film-forming polymer in an organic solvent on a support. This is done by drying it inside.

As the support, any material or shape can be used as long as it has organic solvent resistance. Therefore, although a porous body is preferable, a non-porous body may also be used.

Specifically, for example, glass, metal plates, paper, plastic sheets, hollow fibers, semiconductors, etc. are used. Examples of film-forming polymers include resin-like substances such as polysulfone, polyvinyl chloride, polyvinylidene fluoride, and cellulose acetate, and rubber-like substances such as butadiene rubber, nitrile rubber, acrylic rubber, and fluorine rubber, either singly or in mixtures. used as. Further, these film-forming polymers can also be used in a form containing enzymes, complexes, etc. therein.

These film-forming polymers are applied onto a support as a solution in an organic solvent in which they are dissolved. Coating can be carried out by any commonly used method such as dipping, spraying, brushing, and casting.0 The organic solvent solution of the film-forming polymer coated on the support is dried after coating. Immediately, it is carried out in an atmosphere of about 75-100% relative humidity. When drying under such humid conditions, moisture in the atmosphere enters the solution, and the polymer dissolved in the organic solvent can no longer be stably dissolved. Agglomeration occurs,
Fine pores are created from the gaps between the fine particles of the agglomeration, and the pore size is generally 0.
It is thought that micropores of about 1 to 10 microns are formed in a state where they communicate with both the front and back surfaces of the membrane. Note that drying under such humidity conditions is generally performed at a temperature of about 0 to 100°C, preferably about 10 to 80°C, for about 1 to 60 minutes.

On the other hand, when drying in an atmosphere with a lower relative humidity, the proportion of moisture in the atmosphere is too low to cause aggregation of the polymers, and therefore the polymers remain homogeneously dissolved in the organic solvent. It is thought that because the solvent evaporates and dries, no micropores are formed on the surface of the formed film and it remains flat.

The composite of the present invention formed in this way has a thin polymer film layer formed almost uniformly on the support, which has fine pores communicating with both the front and back surfaces of the thin film. It can be effectively used for various purposes such as.

When a thin polymer film layer into which ion exchange groups can be introduced is laminated on a porous support, it can be used for selective permeation membranes such as ion-selective permeation membranes, charged type ultraporous membranes, and reverse osmosis membranes. Since the fine pores are connected to both the front and back sides of the thin film, the water permeation rate is increased, and since the fine pores are uniformly formed, the selection performance is improved.

When a thin polymer film layer into which ion exchange groups can be introduced is laminated on a semiconductor support, it can be used as an ion-selective electrode. Furthermore, if a system in which an enzyme or a complex is added to a polymer solution is applied to this support and a thin film layer is laminated thereon, this can be used for biosensors, etc. The fine pores are connected to both the front and back sides of the thin film, which increases the response speed, and the uniform formation of the fine pores improves ion permeation performance.
As a result, the effect of improving sensor sensitivity can be obtained.

Next, the present invention will be explained with reference to examples.

EXAMPLE The following various supports were immersed in a 3% by weight carbon tetrachloride solution of a benzyl chloride-styrene equimolar copolymer.

Cover Glass for Microscope +J /” Ropylene porous membrane 2 Nippon Polyplastics product Duraguard 2400 Polyvinylidene fluoride porous membrane: Polyvinylidene fluoride (Kynar product Kynar 460) 20-layer plate, 78 parts by weight of dimethylformamide and polyethylene A mixed solution of 2 parts by weight of glycol (Kanto Chemical Products #6000) was cast onto a glass plate, and after 10 seconds, it was immersed in water.
The polyvinylidene fluoride porous hollow fiber is pulled up, dried, and cleaned.The above mixed solution is wet-dry spun from a hollow annular nozzle, and the outer diameter manufactured by using water for both the core liquid and the coagulation bath. 1.5 mm, inner diameter 1.0
Each support coated with the above-mentioned hollow fiber copolymer solution was immediately removed from the solution at a temperature of 20° C. and relative humidity. The humidity was adjusted to 75%, 88%, 95% or 100% and placed in a saw desiccator to dry for 10 minutes. Note that the humidity was controlled by variously changing the mixing ratio of sulfuric acid and water.

When the surface of the obtained composite membrane was observed using a scanning electron microscope at a magnification of 2,500 times, it was found that pores with a microscopic diameter were formed almost uniformly, as shown in the photograph in FIG. Further, when the cross section of the formed polymer thin film layer was observed, it was found that the pores with the microscopic diameter penetrated the front and back surfaces of the thin film layer.

In the comparative examples, the relative humidity of the drying conditions was 16% and 22%.
, 35% and 57% sweet take respectively.

The surface of the resulting composite membrane was similarly observed using a scanning electron microscope, and no micropores were found on the surface of the chair.
A flat surface was formed.

[Brief explanation of the drawing]

FIG. 1 is a scanning electron microscope photograph showing the surface condition of the composite membrane according to the present invention. Agent'R Physician Yoshiguchi 1 Toshio Toshiro 11th Prisoner Proceedings Neho (Type 6) 1 Indication of the case 1982 Patent Application No. 99564 2 Invention title complex and its manufacturing method 3 Consideration case for amendment Relationship with Patent applicant name (438) B Hon Oil Seal Industry Co., Ltd. 4
Agent (〒105) Address: 1-2-7-5, Shiba Inukon, Minato-ku, Tokyo Attachment 11 of the order for amendment August 1982 2ε3 ('6 Column for detailed explanation of the invention in the specification subject to amendment, drawings) Brief description column and Drawing 7 Contents of the amendment (1) Delete “as shown in the photograph in Figure 1” in line 14-15 of Shinyu 7 of the specification. (2) Section 8 of the specification Delete lines 6-8. (3) Delete the drawing.

Claims (1)

[Claims] 1. A composite formed by laminating, on a support, a thin polymer film layer in which fine pores communicating with both the front and back surfaces of the thin film are formed almost uniformly. 2. The composite according to claim 1, wherein micropores with a pore diameter of about 0.1 to 10 μm are formed in the polymer thin film layer. 3. After coating an organic solvent solution of a film-forming polymer on a support, it is dried in air with a relative temperature of approximately 75 to 100% and the micropores communicating with both the front and back surfaces of the thin film are formed. 1. A method for producing a composite, characterized by laminating thin polymer film layers formed almost uniformly.