JPH04354524A - Production of laminated semipermeable membrane - Google Patents

Abstract

PURPOSE:To provide a laminated semipermeable membrane properly usable to turn brine, seawater, etc., into fresh water by desalting and to produce ultra- pure water required to produce a semiconductor. CONSTITUTION:A thin film of a cross linked polyamide consisting of a polyamine component having two or more amino groups in the molecule and a polyacid halide component having two or more halogenated carbonyl groups in the molecule is formed on a porous base material and a reactive monomer is brought into contact with the thin film in a vaporous state.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for manufacturing a composite semipermeable membrane, and more specifically, a composite semipermeable membrane having a high permeation flux and a high salt rejection rate, which has a thin membrane made of crosslinked polyamide on a porous substrate. The present invention relates to a method for producing a membrane. Such a composite semipermeable membrane according to the present invention can be used, for example, for desalination by desalination of brine, seawater, etc.
It can be suitably used for the production of ultrapure water required for the production of semiconductors.

0002

2. Description of the Related Art In recent years, various composite semipermeable membranes have been proposed as reverse osmosis membranes, in which a semipermeable thin film is formed on a porous substrate. Such composite semipermeable membranes are generally prepared by applying an aqueous solution of the reactive substrate onto a porous substrate, followed by the application of tolylene diisocyanate, isophthaloyl chloride, or trimesic acid chloride dissolved in a water-immiscible organic solvent such as hexane. A semipermeable thin film (dense layer) is formed by contacting with a solution of a polyfunctional crosslinking agent such as, etc., and utilizing an interfacial reaction in which a reactive substrate reacts with the crosslinking agent at the interface between the aqueous phase and the organic phase. It is manufactured by

Specifically, for example, a composite semipermeable membrane using a polysulfone ultrafiltration membrane as a porous base material and polyethyleneimine as a reactive substrate (Japanese Patent Application Laid-Open No. 133282-1982)
), a composite semipermeable membrane using amine-modified epichlorohydrin (Japanese Patent Publication No. 55-38164), a composite semipermeable membrane using a mixture of water-soluble polymers such as polyethyleneimine and polyamino compound monomers (Japanese Patent Publication No. 55-38164), No. 57-27101 and JP-A No. 57-27102), a thin film made of polyamide obtained by interfacial polymerization of a polyfunctional aromatic amine and a polyfunctional acid halide is formed on a porous substrate. Permeable membranes (Japanese Patent Publication No. 63-36803) are known.

0004

[Problems to be Solved by the Invention] Such composite semipermeable membranes are superior in terms of removability, water permeability, heat resistance, etc. compared to conventional asymmetric membranes such as cellulose acetate membranes. However, depending on the actual application, the removal performance is still insufficient, and further improvement is desired. For example, as the capacity of semiconductors increases, even cleaner ultrapure water is required, and current composite semipermeable membranes are insufficient to meet the needs of one-stage desalination of seawater, and even higher There is a need for a composite semipermeable membrane that has salt removal performance and water permeation performance.

[0005]

[Means for Solving the Problems] The present invention has been made to solve these problems, and improves salt blocking performance by further contacting reactive monomer vapor with the above-mentioned composite semipermeable membrane. Regarding how it can be done.

That is, the present invention provides a porous substrate with a crosslinked polyamide thin film consisting of a polyamine component having two or more amino groups in the molecule and a polyacid halide component having two or more halogenated carbonyl groups in the molecule. production of a composite semipermeable membrane, characterized in that a reactive monomer having one or more functional groups capable of reacting with unreacted functional groups in the crosslinked polyamide thin film is brought into contact with the thin film in a vapor state. provide a method.

The porous substrate used in the present invention is not particularly limited as long as it can support a thin film, but usually an ultrafiltration membrane having micropores with a pore diameter of 10 to 500 Å on the surface is used. Examples of materials include polysulfone, polyethersulfone, polyacrylonitrile,
Examples include polyimide, polyamide, ethylene-vinyl alcohol copolymer, cellulose acetate, etc., and polysulfone, polyethersulfone, etc. are particularly preferred from the viewpoint of heat resistance, oxidizing agent resistance, etc. Further, such a porous membrane may be reinforced by being lined with a woven fabric, non-woven fabric, or the like.

The polyamine component in the present invention is an essentially monomeric compound having two or more, preferably two or three, amino groups in the molecule, and the amino groups are
or a secondary amino group, preferably a primary amino group. Specific examples of such polyamine components include, for example, m
- Aromatic primary diamines such as phenylene diamine and p-phenylene diamine, and their alkyl substituted products such as methyl and ethyl, alkoxy substituted products such as methoxy and ethoxy, hydroxyalkyl substituted products, hydroxy substituted products, and halogen substituted products substituted aromatic primary diamines such as
Examples include alicyclic primary diamines such as cyclohexanediamine, alicyclic secondary amines such as piperidine and trimethylpiperidine, aromatic secondary amines such as N,N-diphenylethylenediamine, and xylylene diamine. These can be used alone or in combination.

Further, the polyacid halide component in the present invention is essentially a monomeric compound having two or more halogenated carbonyl groups in the molecule, and preferably has two or more halogenated carbonyl groups in the molecule.
It has one or more halogenated carbonyl groups. This polyacid halide component may be aromatic, aliphatic, or alicyclic. Specific examples of such polyacid halide components include isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, adipoyl chloride, 1,2,3,4-butanetetracarboxylic acid tetrachloride, 1,3, Examples include 5-cyclohexanetricarboxylic acid trichloride,
These can be used alone or in combination.

[0010] In the present invention, on the porous base material,
Applying or impregnating with an aqueous solution containing the above polyamine component,
Next, after contacting with a water-immiscible organic solvent solution containing the polyacid halide component to form a thin film made of crosslinked polyamide by interfacial reaction, a functional group that can react with the unreacted functional groups in this crosslinked polyamide thin film is further added. By bringing a reactive monomer having one or more of these into contact with the thin film in a vapor state, the crosslinking density can be further increased.

Such a reactive monomer is a functional group capable of reacting with an amino group or an acid halide group which is an unreacted functional group of the crosslinked polyamide, such as an acid halide group, a sulfonyl halide group, an aldehyde group, a carboxyl group, an amino group, etc. It is a monomer having Specific examples include isophthaloyl chloride, trimesoyl chloride, glutaryl chloride, adipoyl chloride, glitalyl aldehyde, metaphenylenediamine, ethylenediamine, N-phenylethylenediamine, piperazine, etc. In particular, isophthaloyl chloride, Trimesoyl chloride and metaphenylenediamine are preferably used.

In the present invention, the above-mentioned reactive monomers are brought into contact in a vapor state. Here, the vapor concentration is usually 10-
10-10-2 mol/l, preferably 10-
It is 8 to 10-3 mol/l. The contact time with the composite semipermeable membrane varies depending on the type of composite semipermeable membrane used, the type of reactive monomer, and the vapor concentration, but is usually about 5 to 600 seconds. Further, if necessary, the membrane substrate can be heat-treated before contacting with the vapor of the reactive monomer. Heating temperature is usually about 60-150°C, preferably about 70-130°C
The heating time is about 1 to 10 minutes, preferably 2 to 8 minutes.
It is a minute. After contacting the reactive monomer vapor, the temperature is usually about 60-150°C, preferably about 70-13°C.
Heat treatment is performed at 0° C. for about 1 to 10 minutes, preferably 2 to 8 minutes.

Further, in the present invention, the permeation flux can be further improved by adding an amine salt to the aqueous solution of the polyamine component, if necessary. Such amine salts may be salts of amines and acids, preferably salts of tertiary amines and strong acids, where strong acid means an acid that reacts essentially completely with water to form hydronium ions. do. Specific examples of such strong acids include aromatic sulfonic acids, aliphatic sulfonic acids, alicyclic sulfonic acids such as camphor sulfonic acid, β-trifluoroacetic acid, nitric acid, hydrochloric acid,
Examples include sulfuric acid. Although such amine salts are not limited in any way, in particular, in the present invention,
(a) Trialkylamines such as trimethylamine, triethylamine, tripropylamine, N-alkyl cycloaliphatic amines such as 1-methylpiperidine, N,N
- dimethylethylamine, N,N-dialkylamines such as N,N-diethylmethylamine, N,N-dialkylethanolamines such as N,N-dimethylethanolamine, and bicyclic dialkylamines such as 3-quinuclidinol. (b) a tetraalkylammonium hydroxide such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and benzyltrimethylammonium hydroxide; A water-soluble salt of at least one quaternary ammonium compound selected from the group consisting of benzyltrialkylammonium hydroxide such as benzyltriethylammonium hydroxide and benzyltripropylammonium hydroxide and (c) a strong acid is preferably used. It will be done.

Further, in the present invention, a surfactant such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium laurylsulfate, etc. may be added to the aqueous solution as required. By bringing the composite semipermeable membrane obtained through interfacial crosslinking into contact with reactive monomer vapor to increase the crosslinking density by the method of the present invention described above, the composite semipermeable membrane has a high salt rejection rate while maintaining a high permeation flux. A permeable membrane can be obtained.

[0015]

[Effect of the invention] The composite semipermeable membrane obtained by the present invention is
Compared to conventional composite semipermeable membranes, the removal performance is significantly improved while maintaining a high permeation flux, so it is particularly useful in fields where clean water is required, such as desalination by desalination of brackish water, seawater, etc. It can be suitably used for the production of ultrapure water required for the production of semiconductors, etc.

[0016]

[Examples] The present invention will be explained below with reference to Examples.
The present invention is not limited in any way by these Examples. Comparative Example m-Phenylenediamine 2.0% by weight, sodium lauryl sulfate 0.25% by weight, camphorsulfonic acid 4
．． An aqueous solution containing 0% by weight and 2.0% by weight of triethylamine was applied onto a porous polysulfone membrane substrate, and after removing the excess aqueous solution, 0.1% by weight of trimesoyl chloride was applied.
A hexane solution containing 0% by weight of isophthaloyl chloride and 0.15% by weight of isophthaloyl chloride was poured into the flask, and the mixture was allowed to stand for 2 minutes, after which the excess solution was removed. Next, this membrane base material was heat-dried at 120° C. for 5 minutes to obtain a composite semipermeable membrane in which a crosslinked polyamide thin film was formed on the membrane base material. Using such a composite semipermeable membrane, 150
When a saline solution with a pH of 6.5 containing 0 ppm sodium chloride was treated at a pressure of 15 kg/cm2, the salt rejection rate was 99.25% and the permeation flux was 0.85 m3/m2.
・It was day.

Example 1 3 m-phenylenediamine vapor (vapor concentration 9.5 x 10-6 mol/l) was applied onto the composite semipermeable membrane obtained in the comparative example.
After contacting for 0 seconds, heating was performed at 120° C. for 5 minutes to obtain a composite semipermeable membrane of the present invention. Table 1 shows the results of the same treatment as in the comparative example using such a composite semipermeable membrane.

Examples 2 to 4 In Example 1, except that the vapor of the reactive monomer shown in Table 1 was used instead of the vapor of m-phenylenediamine.
A composite semipermeable membrane was obtained in the same manner as in Example 1. These characteristics are also shown in Table 1.

Example 5 In a comparative example, the membrane substrate was contacted with m-phenylenediamine vapor before being heated and dried. Next, this membrane base material was heat-dried at 120° C. for 5 minutes to obtain a composite semipermeable membrane in which a crosslinked polyamide thin film was formed on the membrane base material. These characteristics are also shown in Table 1.

[0020]

Claims (1)

[Claims] Claim 1: A crosslinked polyamide thin film consisting of a polyamine component having two or more amino groups in the molecule and a polyacid halide component having two or more halogenated carbonyl groups in the molecule is placed on a porous substrate. A method for producing a composite semipermeable membrane, which comprises forming a crosslinked polyamide thin film, and then bringing a reactive monomer having one or more functional groups capable of reacting with unreacted functional groups in the crosslinked polyamide thin film into contact with the thin film in a vapor state.