JPS62180709A - Production of semipermeable composite membrane - Google Patents

Abstract

PURPOSE:To obtain the titled composite membrane with 20-30% increase in the water permeating velocity by allowing a compd. having a reactive amino group to react with a multifunctional reagent on a porous carrier, and bringing the surface into contact with a soln. of the multifunctional reagent. CONSTITUTION:A polymeric porous carrier membrane having several tens - several thousands Angstrom fine pores on the surface is prepared, and an aq. soln. contg. 0.1-10wt% compd. having >=2 reactive amino groups is coated on the surface of the carrier membrane. A hydrocarbonic soln. contg. 0.01-10wt% multifunctional reagent having an acid chloride forming polyamide or polyurea by the reaction with the amino group and an isocyanate is brought into contact with the coat to form a cross-linked membrane. A solvent which is the solvent of the multifunctional reagent and inactive on the membrane and the carrier is brought into contact with the surface of the membrane at temps. ranging from 20 deg.C to a temp. 10 deg.C lower than the b.p. The contact with is regulated to 10sec-10min.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a semipermeable film suitable for ultrafiltration and reverse osmosis using a porous polymer membrane as a support and polyamide or polyurea as an active layer. The present invention relates to a method for producing a composite membrane.

[Prior art] □ Conventionally, semipermeable membranes used industrially include asymmetric membranes made from cellulose acetate, for example, as disclosed in U.S. Pat.
, 133,132 and 3°133.137.

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 these drawbacks of cellulose acetate asymmetric membranes is being carried out mainly in the United States and Japan; , polyamic acid (Japanese Patent Publication No. 121168/1988), crosslinked polyamide acid (Japanese Patent Publication No. 152879/1987), polyimidazopyrrolone, polysulfonamide, polybenzimidazole, polybenzimidacylon, polyarylene oxide, etc. Although materials have been obtained that improve the drawbacks of cellulose acetate membranes, they are inferior to cellulose acetate membranes in terms of selective separation and permeability.

On the other hand, a composite membrane has been developed, which is a semipermeable membrane of a type different from the lobe type, in which a porous support is coated with an active layer that substantially exhibits membrane performance. In composite membranes, it becomes possible to select the optimal materials for the active layer and porous support for each application, increasing the degree of freedom in membrane manufacturing technology. It also has the advantage of being able to be stored in a dry state, unlike the lobe type, which must be stored in a wet state at all times.

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. Of the composite membrane! !
! The manufacturing method is described in U.S. Pat. No. 3,191.815, U.S. Pat.
, 440, 4,277.344, and Japanese Patent Publication No. 56-500062, coating a porous support with an aqueous solution containing a compound having an amine group; There is a method comprising the step of contacting a hydrocarbon-based solution containing a polyfunctional reaction reagent with the above-mentioned aqueous phase.

[Problems to be Solved by the Invention] The inventors of the present invention have investigated ways to improve the performance of such semipermeable composite membranes, and have investigated ways to improve the performance of such semipermeable composite membranes by using a solvent for a polyfunctional reaction reagent on the surface of the membrane obtained in the above manufacturing process. The present invention was achieved by discovering that the performance of the composite membrane, particularly the water permeability, is improved by contacting the composite membrane with water.

[Means for solving problems] In order to achieve the above object, the present invention consists of the following configuration.

"After coating an aqueous solution containing a compound having two or more reactive amino groups on a porous support, a hydrocarbon-based solution containing a polyfunctional reactive reagent is contacted with the aqueous phase, and then further A method for producing a semipermeable composite membrane comprising contacting its surface with a solvent of a polyfunctional reaction reagent.
A support having micropores of several thousand angstroms, comprising polysulfone and polyvinyl chloride.

Known materials made of chlorinated vinyl chloride, polycarbonate, polyacrylonitrile, cellulose ester, etc. are included. Among these, porous polysulfone supports are particularly effective in the present invention. [For raw polysulfone film production, polysulfone is made into a solution in an aprotic polar solvent such as dimethylformamide, cast on a woven or nonwoven fabric made of polyester fibers, and then coagulated in a medium consisting essentially of water ( This is done by so-called wet film forming, etc. The porous polysulfone thus obtained has on its surface micropores with a size of several tens to hundreds of angstroms, which becomes larger from the front surface to the back surface. □ In the present invention, a compound having two or more reactive amino groups (hereinafter referred to as an amino compound) refers to a compound having an amide bond or a urea bond that reacts with a polyfunctional acid chloride or an isocyanate-1 compound. Includes those capable of forming a combination, such as metaphenylene diamine, paraphthalene diamine, 3,5-diaminobenzoic acid, .2
, 5-diaminobenzenesulfonic acid, metaxylidene diamine, varaxylidene diamine, 4,4'-diaminobenzanilide, piperazine, aminomethylpiperidine, ethylenediamine 1,3,5-triaminobenzene, and the like.

The concentration of the amine compound in the amino compound aqueous solution is 0.
1 to 10% by weight, preferably 0.5&5°0. 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 aqueous solution of the amino compound may be coated on the surface of the porous support as long as the aqueous solution is coated uniformly and continuously on the surface.
The coating may be carried out by any known coating method, such as coating the surface of the porous support with the aqueous solution or immersing the porous support in the aqueous solution.

In the present invention, the polyfunctional reaction reagent may be any agent as long as it can react with the amine compound to form a polyamide or polyurea, such as trimesin chloride J benzophenonte 1-lacarboxylic acid chloride,
1-limellitic acid chloride, pyromellitic acid chloride, isophthalic acid chloride, terephthalic acid chloride, naphthalenedicarboxylic acid chloride, diphenyldicarboxylic acid chloride, pyridinedicarboxylic acid chloride, benzenedisulfonic acid chloride, pyromellitic anhydride, 1-limellitic acid chloride Examples include diisocyanate, bis(p-isocyanatophenyl)methane, etc., but considering solubility in membrane forming solvents and performance of semipermeable composite membranes, 1-rimesic acid chloride, isophthalic acid chloride, and terephthalic acid chloride are recommended. preferable.

The solvent for the polyfunctional reaction reagent needs to be inert to the amino compound and the polyfunctional reaction reagent, and insoluble or sparingly soluble in water. Furthermore, the solvent is preferably inert to the porous support. Typical examples of such solvents include liquid hydrocarbons and halogenated hydrocarbons, such as pentane, hexano, heptane, 1,
There is 1,2-trichloro-1,2,2-trifluoroethane. The concentration of the polyfunctional reaction reagent is preferably 09O1
It is preferably 0.02 to 2% by weight, preferably 0.02 to 2% by weight.

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

In the present invention, the solvent for the polyfunctional reagent that is brought into contact with the surface of the membrane formed by the reaction between the amine compound and the polyfunctional reagent may be any solvent as long as it is inert to the membrane and the porous support. Examples include hydrocarbons, halogenated hydrocarbons and alcohols. Representative examples of the solvent include pentane, hequinane, heptane, 1.1.2
-1-lichloro1.2.2-trifluoroethane, methyl alcohol, ethyl alcohol, normal propyl alcohol, and isopropyl alcohol, and a mixture of these may be used. Furthermore, ketones such as acetone and methyl ketone, and ethers such as dioxane, tetrahydrolane and diethyl ether, which adversely affect the membrane and porous support when used alone, can also be used when mixed with the above-mentioned solvents.

Methods of contacting the solvent with the membrane include coating the surface of the membrane with the solvent, immersing the membrane in the solvent, spraying the solvent onto the surface of the membrane, etc. The solvent comes into contact with the entire surface of the membrane. Any method is acceptable as long as it can be done. The temperature of the solvent is not particularly limited, but is generally 20
The temperature range is from 10°C to 10°C lower than the boiling point of the solvent.

The contact time of the solvent with the membrane varies depending on the temperature of the solvent, but is from 10 seconds to 10 minutes.

[Example] The present invention will be specifically explained below using Examples.

Example 1 Taffeta made of polyester 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,
67 pieces/inch horizontally, 160μ thick) was fixed on a glass plate, and polysulfone (Union Carboy 1~
A 15% dimethylborumamide (DMF) solution of Udel 3500 (manufactured by Co., Ltd.) was added to a thickness of 200μ at room temperature (2
A fiber-reinforced polysulfone support (
Hereinafter, a body abbreviated as FR-PS will be created. The FR-PS support obtained in this way (thickness 210-215μ
) is the pure water permeability coefficient at a pressure of 1kq-cJ and a temperature of 25°.
Measured at C 09OO5~0. ol to l/cnf” S
It was eC-atm.

FR-PS support with 2% by weight of metaphenylenediamine
It was immersed in an aqueous solution for 2 minutes. After removing the excess aqueous solution from the surface of the FR-PS support, a solution of 0.1fffffi% trimesine modified chloride dissolved in 1°1.2-1~lichloro1.2.2-trifluoroethane was added until the surface was completely covered. It was coated so that it was wet and left to stand for 1 minute. Next, after turning the membrane vertically and removing the excess solution by draining, apply 1.1.2-1-Rechloro 1.2.2-
The membrane was coated with 1-refluoroethane so that the surface was completely wetted and allowed to stand for 30 seconds.The membrane was turned vertically to drain the liquid, and then dried at room temperature. The composite membrane prepared in this way was subjected to a reverse immersion test using 3.5% synthetic seawater with an osmotic pressure of 25 to 9/CIl+ under conditions of 56 kg/ci and 25°C. Performance of 99.2% and water permeation rate of 0.90 m'/m2 days was obtained.

Comparative example 1 In Example 1, 1.1.2-trichloro.

1.2.2-Trifluoroethane coating was performed in the same manner, but the rejection rate was 99.0%.
A water permeation rate of 0.75 m''/m2 was obtained.

Examples 2 to 4, Comparative Examples 2 to 4 In Example 1 and Comparative Example 1, the compounds shown in Table 1 were used in place of metaphenylene diamine and trimesic acid chloride as amino compound and polyfunctional reaction reagents. The same procedure was performed except that the reverse osmosis performance shown in Table 1 was obtained.

As shown in the above examples, in the present invention, the water permeation rate was increased by 2 to 3 points compared to the conventional method for manufacturing a composite membrane.

[Effects of the Invention] As explained above, in the present invention, it is possible to obtain a composite membrane whose water permeation rate is improved by 20 to 30% compared to conventional composite membrane manufacturing methods.

The reason for this is not clear, but by bringing a hydrocarbon solution containing a polyfunctional reaction reagent into contact with the aqueous phase at an intermediate stage, unreacted substances (monomers, oligomers, etc.) that inhibit water permeability are removed. It is estimated that a relatively large amount of high molecular weight polymers, which contribute to water permeability, remain.

Claims (1)

[Claims] After coating the porous support with an aqueous solution containing a compound having two or more reactive amino groups, a hydrocarbon-based solution containing a polyfunctional reactive reagent is contacted with the aqueous phase, and then further A method for producing a semipermeable composite membrane, which comprises bringing the surface into contact with a solvent of a polyfunctional reaction reagent.