JPS63305918A - Gas separation membrane - Google Patents

Abstract

PURPOSE:To obtain a gas separation membrane having excellent thermal resistance, capability to produce a membrane, and separation efficiency, by employing bis(4-aminophenyl)sulfone and meta- or para-phenylenediamine, as an aromatic diamine component; and isophthalic acid component or terephthalic acid component, as a main component. CONSTITUTION:Copolymer (amine.sulfone) is obtained by reacting, through solution polymerization process etc., bis(4-aminophenyl)sulfone, diamine composed of paraphenylenediamine or methaphenilenediamine, and dicarboxylic acid chloride composed of isophthalic acid chlorile or terephthalic acid chloride or their mixture. The polymer is dissolved in a mixed liquid of, for example, N- methylpyrrolidone and slow-acting coagulants such as glycols, following which the mixed liquid is poured over a glass plate and left as it is then dipped in a non-solvent such as water so that a gas separation membrane having an asymmetrical membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a gas separation membrane having good separation performance.

(Prior art) Composite membranes made by combining polysulfone and silicone polymer are known as gas separation membranes (Japanese Unexamined Patent Publication No.
3-86684). This membrane is commercially available from Monsanto Company as a prism separator. The silicone polymer used in this membrane has poor heat resistance, and its separation performance is significantly reduced at high temperatures (for example, 100° C.).

Aromatic poly(amide) is known as one of the polymers with good heat resistance. In particular, poly(amide) obtained from a mixed diamine component of bis[4-(4-aminophenoxy)phenylcosulfone and metaphenylenediamine and isophthalic acid] There is a report that the gas separation performance of (Amidosha Ether Sulfone) is excellent (Japanese Patent Application Laid-Open No. 81-259727).

A membrane obtained from this polyamide has better gas separation performance than the polysulfone described above, and also has excellent heat resistance. However, the separation performance cannot be said to be sufficient.

(Problems to be Solved by the Invention) As a result of intensive studies to obtain a material with excellent separation performance, film-forming properties, and heat resistance, the present inventors found that a specific copolymerized poly(amide sulfone) It has been found that the separation performance is significantly superior while maintaining good heat resistance and film forming properties.

(Means for solving the invention) That is, in the present invention, bis(4-aminephenyl)
Excellent heat resistance due to the film made of poly(amide sulfone) whose acid component is an aromatic diamine component containing sulfone and meta- or para-phenylenediamine, an isophthalic acid component or a terephthalic acid component, and a mixture of both. , a gas separation membrane having good film formability and separation performance was obtained.

One of the diamines used in the polymers of the present invention is bis(4-
Examples of aromatic diamines used together with bis(4-aminophenyl)sulfone include paraphenylenediamine and metaphenylenediamine.

These diamines may be used alone or in a mixture of two or more.

The acid component used is mainly an isophthalic acid component or a terephthalic acid component, or a mixture of both acid components.

In addition, an aromatic dicarboxylic acid component may be used, and the amount used is preferably 20 mol % or more based on the total acid components.

The polymer is obtained by reacting a diamine with a dicarboxylic acid chloride. The reaction method may be a solution combination method or an interfacial polymerization method. The shape of the separation membrane obtained from this polymer is
There are no particular restrictions on the membrane type, such as a 1' membrane, a spiral type, or a hollow fiber type, but it is desirable that the membrane has an asymmetric structure in order to improve separation performance, especially gas permeation.

The polymer is dissolved in a suitable polar solvent such as N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide. It is also dissolved in a mixed solvent of the above solvent and glycols, which are slow coagulating agents when forming an asymmetric membrane. Membranes are therefore usually prepared from solutions of the polymer in these solvents. For example, an asymmetric membrane is obtained by dissolving the polymer in a mixture of N-methylpyrrolidone and glycols as a slow-coagulating agent, casting it on a glass plate 11, leaving it for a certain period of time, and then immersing it in a non-solvent such as water. I can do it.

(Example) The present invention will be specifically explained below with reference to Examples.
This does not limit the invention. In the examples, gas separation performance, reduced specific viscosity, etc. were measured according to the following guidelines.

(1) Reduced specific viscosity (ηsp/c) Solvent N,N-dimethylacetamide 4 degrees 30 degrees
C concentration 500 g/100. nO ■ Preparation of membrane 5 g of polymer is dissolved in 45-N-methylpyrrolidone. The solution was cast onto a polypropylene film fixed to a glass plate, and then placed in a drying mold at 80°C for 1 hour to evaporate the solvent. After cooling to room temperature, the film was peeled off from the polypropylene film and placed on a glass plate-L. After fixing it on a glass plate, place it in a vacuum dryer at 150°C.
The temperature was maintained at 1 mmHg or less for 14 to 16 hours, and residual solvent was removed and heat treatment was performed. Using the obtained membrane, gas separation performance and heat resistance were measured.

(3) Measurement of gas separation performance Gas separation performance was measured at 30°C using a Seikagaku-style gas permeation measuring device. The permeability coefficients of hydrogen and carbon monoxide were 39 in total, and the separation coefficient was determined from the ratio of the two.

(4) Measuring station for Ma1 (yield l!lIV degrees) The temperature at which the sample film begins to stretch under load was measured using a thermomechanical special 1'/I measuring device manufactured by IN Seisakusho. The heating temperature was 10°C/min, and the atmosphere was a mixed gas (0°/N2=2
1/79).

(5) 2.0g of dissolved t/l test polymer was added to 10Jt+ of N-methylpyrrolidone.
The mixture was stirred at +30°C and the degree of dissolution was visually judged 1-1.

Comparative Example 1 Bis(4-ami/phenyl)sulfony/65.6 g (0,264 mo(2)) was placed in a 500-flask equipped with a stirrer, thermometer, nitrogen inlet tube, and sample input L-1, and nitrogen gas Dehydrated N-methylpyrrolidone 50
Add 0□ρ and stir. After completely dissolving, soak in a water bath.
Cool until U reaches 4°C.

Isophthalic acid dichloride powder from reagent input [ ] 53.7
g (0,264 mof2) and stirred for 1 hour while cooling in a water bath. Thereafter, the mixture was reacted at room temperature for 1 hour, and then poured into 3Q methanol to obtain a polymer solid. The polymer was washed with water five times using a household mixer and then dried under reduced pressure at 140'C. The reduced specific viscosity of the polymer was 0.77, and the yield temperature was 340'C. The hydrogen permeability coefficient was 3. 6X 10-” ci・cw+/cJ
The separation coefficient for sec·cmHg, hydrogen, and carbon oxide was 88. Moreover, this polymer dissolved under the above dissolution test conditions.

Example 1 In the same manner as in Example 1, a copolymer based on a mixed diamine system of bis(4-aminophenyl)sulfone and paraphenylenediamine was obtained. Table 1 shows the composition, heat resistance, solubility, and gas separation performance of the obtained polymer.

Example 2 In the same manner as in Example 1, 59.0 g (0,238 mQ) of bis(4-aminophenyl)sulfone, 4.54 g (0,042-) metaphenylenediamine, and 56.87 g (0,042-) isophthalic acid dichloride were prepared. 280, J). The reduced specific viscosity of the obtained polymer was 1.19,
The yield temperature was 352°C. The hydrogen permeability coefficient is 2.
9X10-10 辣・cm / CM111sec-c+
The separation coefficient for +Hg, hydrogen, and -carbon oxide was 104. Further, this polymer was dissolved under the dissolution test conditions described in 1-.

Example 3 In the same manner as in Example 1, 733.7 g of bis(4-aminophenyl)sulfo (0,13 EimoQ), 22.0 g of metaphenylenediamine (0,204 moQ), and 69.0 g of terephthalic acid dichloride (0,340 moQ) were prepared. )
Polymerization was carried out using The reduced specific viscosity of the obtained polymer is 1
．． 92. Surrender? ! (The temperature was 364°C. The hydrogen permeability coefficient was 2.3X10-10 cfl” cm/
(+rt" 5eC-ci Hg, hydrogen, -carbon oxide) separation factor was 100. Also, this polymer
-Dissolved under the above dissolution test conditions.

Margins below (Effects of the Invention) Since the membrane obtained from the polymer of the present invention has a high yield point, it exhibits a high separation coefficient even at high temperatures (for example, 100° C.). In particular, the protective membrane is suitable for separating low molecular weight gases such as hydrogen and helium from high molecular weight gases such as nitrogen and carbon monoxide.

Claims (1)

[Claims] The aromatic diamine component is bis(4-aminophenyl) sulfone and meta or paraphenylene diamine, and the main acid component is an isophthalic acid component or a terephthalic acid component, and a poly(amide sulfone) which is a mixture of both. Characteristic gas separation membrane.