JPH0451206B2 - - Google Patents

Description

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

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

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, However, fine particles 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 to investigate the cause of this phenomenon, the present inventors have discovered that coating an organic solvent solution of a film-forming polymer on a support and drying it, which is commonly used as a composite means, I learned that the atmospheric humidity has a big effect on drying.
It has been found that by keeping the 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 method for producing a composite in which a thin polymer film layer in which micropores communicating with both the front and back surfaces of the thin film are formed almost uniformly is laminated on a support.
The production of the composite is carried out by applying an organic solvent solution of the film-forming polymer onto the support, followed by a relative humidity of about 75-100%.
This is done by drying in an atmosphere with controlled humidity.

As a support, as long as it has organic solvent resistance,
Any material or shape can be used, and therefore, a porous body is preferable, but a non-porous body may also be used. Specifically, for example, glass, metal plates, paper, plastic sheets, hollow fibers,
Semiconductors and the like are used. Examples of film-forming polymers include resinous substances such as polysulfone, polyvinyl chloride, polyvinylidene fluoride, cellulose acetate, butadiene rubber, nitrile rubber,
Rubber-like substances such as acrylic rubber and fluorocarbon rubber can be used alone or as a mixture. 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. Application can be carried out by any commonly used method such as dipping, spraying, brushing, and casting.

Drying of an organic solvent solution of a film-forming polymer coated on a support is carried out immediately after coating at a relative humidity of about 75 to
It will be held in 100% atmosphere. 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.
As a result, aggregation of polymers occurs, and micropores are created from the gaps between the fine particles of the aggregation, generally with a pore size of about 0.1 to
It is thought that micropores of about 10 μm are formed in communication with both the front and back surfaces of the membrane. In addition, drying under such humidity conditions is generally about 0 to 100℃,
It is preferably carried out at a temperature of 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 uniformly 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 maintains a flat state.

The composite of the present invention thus formed is
Since a polymer thin film layer in which fine pores are formed almost uniformly on both the front and back surfaces of the thin film is laminated on the support, it can be effectively used for various purposes such as the following.

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. Because the micropores are connected to both the front and back surfaces of the thin film, the response speed is increased, and because the micropores are uniformly formed, the ion permeation performance is improved, which in turn improves sensor sensitivity. It will be done.

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

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

Microscope cover glass polypropylene porous membrane: Syuraguard 2400, manufactured by Nippon Polyplastics Co., Ltd. Polyvinylidene fluoride porous membrane: Polyvinylidene fluoride (Kynar 460, manufactured by Kynar Corporation) 20 parts by weight, dimethylformamide 78 parts by weight, and polyethylene glycol (Kanto Chemical Product #) 6000)2
Polyvinylidene fluoride porous hollow system manufactured by casting part by weight of the mixed solution onto a glass plate, immersing it in water after 10 seconds, pulling it up and drying it: The above mixed solution is poured into dry and wet form through a hollow annular nozzle. Hollow fibers with an outer diameter of 1.5 mm and an inner diameter of 1.0 mm manufactured by formula spinning and using water for both the core solution and coagulation bath. Each support coated with the copolymer solution by dip coating was
Immediately after being lifted from the solution, the temperature is 20℃.
The sample was placed in a desiccator with a relative humidity of 75%, 88%, 95%, or 100% and dried 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 micropore diameters were formed almost uniformly. Furthermore, when the cross section of the formed polymer thin film layer was observed, it was found that the micropores penetrated both the front and back sides of the thin film layer.

Comparative Example In the example, the relative humidity of the drying conditions was 16%,
changed to 22%, 35% or 57%, respectively. The surfaces of the resulting composite membranes were similarly observed using a scanning electron microscope, but no micropores were formed on any of the surfaces, and a flat surface was formed.

Claims (1)

[Claims] 1 After applying an organic solvent solution of a film-forming polymer onto a support, it is dried in an atmosphere with a relative humidity of about 75 to 100%, so that the micropores communicating on both the front and back surfaces of the thin film are almost uniformly formed. 1. A method for producing a composite, characterized by laminating thin polymer film layers formed on.