JPS62171713A - Production of semipermeable composite membrane - Google Patents

Abstract

PURPOSE:To increase the water permeating velocity and to obtain stabilized performance by using a compd. having an amino group, and forming a cross- linked polymer on a porous carrier which has been immersed in water at 50-100 deg.C and heat-treated. CONSTITUTION:Wet film-forming polysulfide having fine pores whose size is controlled to several tens - several hundreds @ on the front surface and progressively increased toward the rear surface is used in the porous carrier. The carrier is dipped in water at 50-100 deg.C, and heat-treated. An aq. soln. of dimethylformamide, etc., can be added to the water. An aq. soln. of a compd. having >=2 reactive amino groups is then coated on the porous carrier. The concn. of preferably adjusted to 0.1-10wt%. An org. soln. of a multifunctional reactive reagent capable of forming polyamide and polyurea by the reaction with the amino compd. is brought into contact with the coat. The concn. is preferably regulated to 0.01-10wt%. Consequently, the water permeating velocity can be improved.

Description

Detailed Description of the Invention (Technical Field) The present invention provides a semipermeable composite membrane suitable for ultrafiltration and reverse osmosis, which has a porous polymer membrane as a support and polyamide or polyurea as an active layer. Relating to a manufacturing method.

(Prior Art) Conventionally, semipermeable membranes that have been used industrially include asymmetric membranes made from cellulose acetate, such as those disclosed in US Patent No. 3.
There are lob-type films described in No. 133.132@Specification a and No. 3 133.137@Specification a. However, this membrane has problems with hydrolysis resistance, microbial resistance, chemical resistance, etc. In particular, when trying to improve permeability, it is not possible to manufacture a membrane that has both pressure resistance and durability, so it is not used in some cases. However, it has not yet been put to practical use in a wide range of applications. Research into new materials that eliminate the drawbacks of these asymmetric cellulose acetate membranes is being actively conducted mainly in the United States and Japan, but aromatic polyamides, polyamide hydrazides (U.S. Pat. No. 3,567,632), polyamide acid (Special Publication No. 50-121168@publication), crosslinked polyamide acid (
Although materials that improve some of their drawbacks have been obtained, such as polyimigzopyrrolone, polysulfonamide, polybenzimidazole, polybenzimidacylon, and polyarylene oxide, the J type It is inferior to the P-acetate Rulose membrane in terms of selective separation or permeability.

On the other hand, in the Lob type, a composite membrane has been developed in which a porous support is coated with an active layer that substantially exhibits membrane performance as a semipermeable membrane that uses a mold as a stomach. In composite membranes (31, select the active layer and porous support for each application);
This makes it possible to increase the degree of freedom in film forming technology. Another advantage is that it can be stored in a dry state, unlike the lobe type, which must be kept constantly moist.

Among such composite membranes, composite membranes in which the active layer is made of polyamide or polyurea have high membrane performance, particularly water permeability, and have therefore become the mainstream in the development of semipermeable composite membranes. The method for manufacturing the composite membrane is described in U.S. Pat. No. 3,191.815;
Specification No. 3.744.642, No. 4,039,4
J disclosed in Specification No. 40, Specification No. 4.277.344, and Japanese Patent Publication No. 56-500062:
There is a method consisting of a step of coating a porous support with an aqueous solution containing a compound having an amino group and a step of bringing a hydrocarbon solution containing a polyfunctional reaction reagent into contact with the aqueous solution phase described below.

Conventionally, in the manufacturing method of such composite membranes, the membrane performance has fluctuated greatly, and stable membranes [<? '191775 shows that the water permeation rate changes by more than twice when the film is coated under the same conditions.

(Problems to be Solved by the Invention) The present inventors investigated the manufacturing method of the composite membrane as described above, and found that the porous support was the main cause of fluctuations in membrane performance, particularly water permeation rate. We have discovered that stable membrane performance can be obtained by treating the support with hot water, and have arrived at the present invention.

(Means for solving problems) In order to achieve the above object, the present invention consists of the following groove configuration.

``Semipermeability comprising coating a porous support with an aqueous solution containing a compound having two or more reactive amino groups and then contacting a hydrocarbon solution containing a polyfunctional reactive reagent with said aqueous phase. A method for producing a semipermeable composite membrane, characterized in that the porous support is previously immersed in water at a temperature range of 50°C to 100°C and heat-treated. A porous support is a support that has micropores of tens to thousands of angstroms on its surface, and is made of polysulfone, polyvinyl chloride, chlorinated vinyl chloride, polycarbonate, polyacrylonitrile, cellulose ester, etc. Includes known ones. Among these, porous polysulfone supports are particularly effective in the present invention. Porous polysulfone films can be produced by casting polysulfone in a solution in an aprotic polar solvent such as dimethylformamide onto a woven or non-woven material made of polyester fibers, and then casting the polysulfone in a medium consisting essentially of water. This is carried out using a so-called wet 1U film, etc., which is coagulated (gelled) with water. The porous polysulfone prepared in this manner (1) has micropores on its surface with large serrations of several tens to hundreds of angular pores and a loam size, which grow larger from surface to surface. The resulting porous support is immersed in water at a temperature ranging from 50°C to 100°C.

This water contains the solvent used in forming the porous support film,
For example, a water-soluble liquid such as dimethylformamide may be added as long as the weight ratio to water is 175 or less.

In the present invention, a compound having two or more reactive amino groups (hereinafter referred to as an amine compound) refers to a compound that reacts with a polyfunctional acid chloride or isocyanate compound to form a polymer having an amide bond or a urea bond. For example, meta-phenylene diamine, para-phenylene diamine, 3,5-diaminobenzoic acid, 2.5
-diaminobenvinsulfonic acid, metaxylidene diamine, varaxylidene diamine, 4. Examples include f-diaminopenzanite, piperazine, aminomethylpiperidine, ethylenecyamine 1,3,5-triaminobenbin, and the like.

The solubility of the amine compound in the amine compound aqueous solution is 0.
1-10.0% by weight, preferably 0.5-5. −0 weight. Further, the amine compound aqueous solution may contain a surfactant, an organic solvent, etc. as long as they do not interfere with the reaction between the amine compound and the polyfunctional reaction reagent.

The amino compound aqueous solution can be coated on the surface of the porous support if the aqueous solution is uniformly and continuously coated on the surface.
The coating may be carried out by any known method such as coating the surface of the porous polymer membrane with the aqueous solution or immersing the porous polymer membrane in the aqueous solution.

In the present invention, the polyfunctional reaction reagent may be any reagent that can react with the amine compound to form polyamide or polyurea, such as trimesic acid chloride, benzophenone tetracarboxylic acid chloride, trimellitic acid chloride, etc. Chloride, pyromellitic acid chloride, inphthalic acid chloride, terephthalic acid chloride, naphthalenedicarboxylic acid chloride, diphenyldicarboxylic acid chloride, pyridinedicarboxylic acid chloride, benzenedisulfonic acid chloride, pyromellitic anhydride,
Tolylene diisocyanate, his(p-sardine-1)
-phenyl)methane, etc., but trimesic acid chloride, isophthalic acid chloride, and terephthalic acid chloride are preferable in consideration of solubility in membrane forming solvents and performance of semipermeable composite membranes.

The solvent for the polyfunctional reaction reagent is the amino compound cr3
and polyfunctional reaction reagents, and must be insoluble or sparingly soluble in water. Furthermore, said 2F
J'R is preferably inert to the porous support. Representative examples of such solvents include liquid hydrocarbons and halogenated hydrocarbons, such as pentane, hexano, heptane, 1.1.2-trichloro[:l-1.2.2-trifluoroethane]. The concentration of polyfunctional reaction reagent is 0.0
The amount is 1 to 10% by weight, preferably 0.02 to 2% by weight.

The method of contacting the polyfunctional reaction reagent with the aqueous amine compound phase may be carried out in the same manner as the method of coating the porous support with the aqueous solution of the amino compound.

(Example) EXAMPLES Hereinafter, the present invention will be briefly and specifically explained with reference to Examples.

Example 1 Taffeta made of polynisdel fibers with a length of 30 cm and a width of 20 cm (multifilament yarn of 150 denier in both warp and weft, weaving density of 90 pieces/inch in length,
A 15% dimethylformamide (DMF) solution of polysulfone (Udel 3500 manufactured by Union Carbide Co., Ltd.) was fixed on a glass plate to a thickness of 200 μm. at room temperature (2
A fiber-reinforced polysulfone support (hereinafter abbreviated as FR-PS support) is produced by casting the support at 0° C., immediately immersing it in pure water, and letting it stand for 5 minutes. This FR-P
The S support was immersed in water at 90° C. for 5 minutes, soaked in hot water at 98°C, and then cooled in water at room temperature.

Next, this FR-PS support was immersed in a 2% by weight aqueous solution of metaphenylenediamine for 2 minutes. After removing the excess aqueous solution from the surface of the FR-PS support, 1,1.2-
1 to Richloro 1.2.2-trifluoroethane to trimesic acid chloride 0.

The surface was coated with a solution containing 1% by weight so that it was completely wetted and allowed to stand for 1 minute. The membrane was held vertically and excess solution was removed by draining, followed by drying at room temperature. The above operation was repeated five times to create five membranes, and the reverse osmosis performance was measured at one point for each of the six membranes. Measurement Conditions iJ3 The results of the measurement are shown in Table-1.

In Tables 1 and 2, the coefficient of variation is 110, which is the standard deviation divided by the average value.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the FR-PS support was not treated with hot water. The results are shown in Table-1.

Examples 2 to 4, Comparative Examples 2 to 1/1 The same procedures as in Example 1 and Comparative Example 1 were performed except that the compounds shown in Table 1 were used as the amine compound and the polyfunctional reaction reagent, and the results shown in Table 2 were obtained. I got it.

(Effects of the Invention) As shown in the above examples, in the present invention, the water permeation rate is improved and stable performance is improved by 1q compared to the conventional method for manufacturing a composite membrane.

Claims (2)

[Claims] (1) After coating a porous support with an aqueous solution containing a compound having two or more reactive amino groups, a semi-finishing process consisting of contacting a hydrocarbon solution containing a polyfunctional reaction reagent with the aqueous solution phase. A method for producing a semi-permeable composite membrane, characterized in that the porous support is previously immersed in water at a temperature range of 50°C to 100°C and heat-treated. (2) The method for producing a semipermeable composite membrane according to claim (1), wherein the porous support is porous polysulfone.