JPS62102802A - Separating membrane - Google Patents

Abstract

PURPOSE:To obtain a gas separating membrane having excellent heat resistance, film formability and separating performance by using bis(3-aminophenyl)sulfone and methaphenylene diamine as a diamine component and isophthalic acid component as a main acid component. CONSTITUTION:After 30-95mol% bis(3-aminophenyl) sulfone and 5-70mol% methaphenylene diamine are dissolved in a polar solvent such as N-methyl pyrolidone, etc., the soln. is cooled and an isophthalic acid chloride is added thereto to effect reaction and to obtain a polymer. The soln. prepd. by dissolving such polymer in the N-methyl pyrolidone, etc., is cast on a PP film fixed on a glass sheet and thereafter the solvent is evaporated. The membrane is stripped from the film and is fixed onto a glass sheet. The membrane is subjected to the removal of the residual solvent and a heat treatment in a vacuum dryer, by which the gas separating membrane consisting of poly(amide.sulfone) is obtd.

Description

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

(Prior art) A composite membrane made by combining polysulfone and silicone polymer is known as a model for gas component π (Japanese Patent Laid-Open No. 53
-813684), and this mark is commercially available as a prism separator from Monsanto. The silicone polymer used in this can has poor heat resistance, and its separation performance is greatly reduced at high temperatures (for example, 100''C).

Aromatic as one of the good polymers of it a Pl,!
! Liamide is known. In particular, it has been reported that poly(amide ether sulfone) obtained from bis(ll-(4-aminophenoquine)phenyl)suleno and isophthalic acid or terephthalic acid has excellent gas separation performance (special σ (1987-55006).The membrane obtained from this polyamide has better gas separation performance than the polysulfone described in n'l and also has excellent heat resistance.However, the separation performance is not sufficient.

(Problem to be solved by the invention) Disadvantages of the prior art, namely: ■ Several times more heat resistant ■ Solvent-soluble (4-d ■ Insufficient gas separation performance It is.

(Another Means for Solving the Invention) That is, the present invention provides bis(3-ami7phenyl)sul1
Poly(amide sulfo/
) The gas separation membrane having excellent heat resistance, film formability, and separation performance is used in an amount of 5 mol% to 70 mol% based on the total i1 of both. If it is more than 70 mol%,
The solubility of the polymer is significantly reduced, and the solvent conditions for forming an asymmetric membrane structure are strictly limited, making it difficult to obtain a good separation membrane. Metaphenylenediamine is 5 mol%
In the range of ~70 mol %, both separation performance and IB dissolution performance are excellent. Preferably, a range of 10 mol % to 70 mol % of mekphenylene/diamine is particularly excellent.

As a diamine component to be copolymerized, metaphenylene diamine is excellent. Even if para-phenylene diamine, which is an isomer with a different bonding position, is used instead of meta-phenylene diamine, there is no effect (the tit coefficient decreases).

As the acid component, an isophthalic acid component is mainly used. In addition, an aromatic dicarboxylic acid component can be used, but the amount used is preferably 20 mol % or less based on the total acid components.

The polymer is obtained by reacting a diamine with a dicarboxylic acid chloride. As the reaction method, a solution polymerization method or an interfacial combination method is adopted. The obtained 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 can be formed by dissolving the polymer in a mixture of N-methylpyrroliton and glycols as a coagulant, casting it on a glass plate, leaving it for a certain period of time, and then immersing it in a non-solvent such as water. Obtainable.

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

In the present invention, for example, as a low molecular weight diamine used together with bis(3-aminophenyl) sulfone, the previously proposed phenylenediamine is used. It exhibits extremely excellent At-temperature properties 1iE in the system in which it is used as a component.

(Example) The present invention will be specifically explained below using Examples, but the present invention is not limited thereto.

In addition, in the examples, gas branching performance, binary ratio ratio, etc. were measured according to the following procedures.

(1) Reduced specific viscosity (ηs p/c) solvent N
, N-dimethylformamide/! Temperature: 30°C Concentration: 500 μ/mQ (2) Preparation of 112 5 g of polymer is dissolved in 45 m 2 of N-methylpyrrolito. After the solution was cast onto a polypropylene film fixed to a glass plate-F, it was placed in a dryer at 80°C for 1 hour.
Allow time to evaporate the solvent. After cooling to room temperature, the film was peeled off from the 1τ repropylene film and placed on a glass plate. After fixing it on a glass plate, put it in a vacuum dryer for 150"
The temperature was maintained at 1 ova Hg or less for 14 to 16 hours at C, 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 α1 determination of gas separation performance was performed at 30° C. using a Seikagaku-style gas permeation measuring device. The permeability coefficients of hydrogen and carbon monoxide were calculated by J[, and the separation coefficient was determined from the ratio of the two.

(4) Endurance! Measurement of A property (yield temperature) The temperature at which the sample film begins to stretch under load was measured using a thermomechanical property measuring device manufactured by 8 Ko Seisakusho. The temperature increase rate is lO°C/mi
n, the atmosphere is a mixed gas (01/Nl = 21/79).

(5) Solubility test 14.0 g of the polymer was stirred at 100° C. in a mixed solvent of 16.9 g of N,N-dimethylformamide and 9.1 g of propylene glycol, and the degree of dissolution was visually determined.

Example l.

5 with a stirrer, thermometer, nitrogen inlet tube and test tube
Cool until 15.5 g (0,0624 mo I) of bis(3-amino/phenyl) sulfone is dissolved in a 00 mff flask. Isophthalic acid dichloride powder 18 from the reagent inlet
．． 1 g (0,0802 mo +) was added and stirred for 1 hour while cooling in a water bath. Thereafter, the mixture was allowed to react in chamber 4 for 1 hour, and then poured into 21+ 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 is 0.81. The yield temperature was 207°C. Hydrogen permeability coefficient is 1.5 x 10"'cm', cs
/ cm”, SeC.

The separation coefficient for cs Hg, hydrogen, and carbon oxide was 185.

Moreover, this polymer dissolved under the above dissolution test conditions.

Example 2 Example 1. In the same manner as above, polymers with different metaphenylene diamif contents were obtained. The composition, heat resistance, solubility and gas publication performance of the obtained polymer are shown in Table 1.

Comparative Example 1 Example 1. In the same reactor as above, 42.3 g (0,099
9 mol) in 300 mQ of N-methylpyrrolidone,
After cooling in a water bath to 4°C, 20.3 g (0,10100 O+) of isophthalic acid dichloride powder was added, and the rest was as in Example 1. A polymer having a reduced specific viscosity of 1.25 was obtained in the same manner as above. The yield temperature of the polymer is 315°C, and the permeability coefficient of water cable is 3.3 x 10-"cm', cs/>",
5 e C, csHg 1 water or less Margin 1 From Table B and Metaphenylenediamine Table 1, the following is clear.

1. When the 411 composition ratio of bis(3-amino/phenyl)sulfo/ becomes low, the solvent solubility decreases.

2 The combination of bis(3-amino/phenyl) sulfo/ and metaphenylenediamine is described in the prior art (Japanese Unexamined Patent Publication No. 58-55
It shows superior gas separation performance compared to Comparative Example 1 based on 0013). Bis(3-aminophenyl)sul, 1
．． If the composition ratio of / is sufficient, the solvent solubility is also excellent.

(Function) According to the present invention, a separation membrane is provided which provides a polymer with low solvent solubility that does not impede membrane formability, and has excellent gas separation performance and heat resistance.

Claims (1)

[Claims] Bis(3-aminophenyl)sulfone 30 mol% to 95
1. A separation membrane comprising a poly(amide sulfone) having 5 mol% to 70 mol% of metaphenylenediamine as a diamine component and an isophthalic acid component as a main acid component.