JPS5966310A - Method for wetting of dry polysulfone semipermeable membrane - Google Patents

Abstract

PURPOSE:To rewet a dry polysulfone semipermeable membrane without deforming or deteriorating the same, by treating said semipermeable membrane with pressurized steam at a specific temp. CONSTITUTION:Polysulfone and diethylene glycol are dissolved in N-methyl-2- pyrrolidone to form a film forming solution which is, in turn, applied onto a glass plate and the formed film is directly immersed in water to obtain a wet polysulfone semipermeable membrane. After this membrane is immersed in a 30% aqueous glycerine solution for 24hr, it is dried at an ambient temp. to obtain the dry membrane. In order to rewet this membrane, it may be subjected to immersion treatment in steam at 120 deg.C for 20min. Thus rewetted membrane is restored in the capacities of the initial wet membrane and, because of high temp. pasteurization, it is suitable for sterilization.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for wetting polysulfone dry semipermeable membranes.

Semipermeable membranes made of polysulfone are manufactured as wet membranes,
Generally, it is subjected to, for example, ultraviolet filtration without drying. However, for storage, transportation, and post-treatment of 'r'A, it is desirable to dry the wet film to form a dry film. - There are cases where it is desirable. In such cases, membranes made of inherently hydrophilic polymers such as cellulose acetate membranes, polyamide membranes, polyimide membranes, etc. can be easily re-wetted by drying and recycling the wet membrane and then soaking it in water. However, since polysulfone is inherently hydrophobic, a wet membrane made of polysulfonate does not easily rewet even if the wet membrane is immersed in water after drying.

For this reason, a method has been proposed in which vapor of lower aliphatic alcohol is filled into the semi-permeable micropores and then condensed to wet the polysulfone dry semipermeable membrane. Iruga (US 11!1 Patent No. 3,632,404)
According to this method, the semipermeable membrane may be deformed/stiffened and deteriorated, and since organic solvent vapor is used, there is a risk of environmental pollution, and energy costs are required. In addition to other methods, a method of immersing the dried membrane in an aqueous surfactant solution has also been proposed (Special Section 1982-10).
No. 161.3), after rewetting the membrane must be washed for an extended period of time with water to remove the surfactant from the membrane;
On the other hand, there is a risk that surfactants may remain in the membrane even after such cleaning treatment, such as food, pharmaceuticals, pure water, etc.
For applications in fields that require precision, such as sterile water and artificial organ collars]T
This method is not applicable.

The present invention has been made to solve the problems mentioned above, and is capable of rewetting a dry membrane without deforming or deteriorating it, thereby restoring the performance of the original wet membrane. 4.Providing a moisturizing method □;
The method of wetting the dry membrane according to the present invention is characterized in that the dry membrane is treated with pressurized steam at 100 to 130°C.

A preferred polysulfone drying membrane to which the method of the present invention can be applied is an aromatic polysulfone drying membrane, preferably a polysulfone having a repeating unit represented by the formula or a polysulfone having a repeating unit represented by the formula It is a dry film consisting of

As is already known, polysulfone wet semipermeable membranes are obtained by casting a solution of polysulfone containing additives on a suitable substrate and then immersing it in water. The wet membrane is immersed in, for example, several tens of grams of glycerin, water, etc., and then dried and manipulated under mild conditions to form the membrane.
・ , ・ ・ The method of the present invention can be applied by removing water from ゝ. ,,,ordinary r minutes-
An ultrafiltration membrane having a molecular weight of about 100 (] to 1,000,000 is suitable).

According to the method of the present invention, such a polysulfone, dry semipermeable membrane is brought into contact with pressurized steam at 100 to 130°C to rewet it, thereby reducing water permeability and solute removal. The original performance of the membrane can be restored without substantially changing the basic performance of the membrane, such as the moisture content.

The temperature of the steam to be treated is preferably 00-:1.3° C. If the temperature is lower than this, the stability of the treatment steam will be poor, the treatment will be non-uniform, and this will cause variations in film properties. If the treatment temperature is too high, the membrane tends to be deformed or the pore size of the membrane becomes different from that of a wet-flooded membrane, which is undesirable. Processing time is not particularly limited, but 5 minutes or more
About 30 minutes is sufficient. If the treatment time is too short, rewetting of the dried membrane and recovery of membrane properties will be insufficient, resulting in non-uniform treatment. If the treatment time is too long, the membrane tends to be deformed and the pore size of the membrane becomes different from that of the wet membrane, which is undesirable.

According to the method of the present invention, it is possible not only to rewet a dried semipermeable membrane but also to sterilize the semipermeable membrane, making it a particularly suitable method for applications that require sterilization. However, although the present invention will be explained below with reference to actual examples, the present invention is not limited to these embodiments in any way. In addition, in the following, parts mean parts by weight.

Example 1 A film-forming solution was prepared by dissolving 30 parts of polysulfone (P-1700, manufactured by Uniono Carbide Co., Ltd.) consisting of a repeating unit represented by the formula, 30 m tosyethylene glycol in 100 parts of 19-methyl-2-pyrrolidone. The film-forming solution was applied on a glass plate at room temperature, immediately poured into water at 20°C, and immersed for 24 hours to obtain a semipermeable polysulfone membrane. Polyethylene glycol (hereinafter referred to as P
It's called Fig. ) pressure 4 k for 0.2% water bath solution
g/cnf Te (7) Rejection rate force 69.0% Water permeation rate force 0.16'me, '1cyyf minute6
□This wet film was immersed in a 30% aqueous glycerin solution for 24 hours, and then dried at room temperature to obtain a dry film. 'This dried membrane was re-wetted by treating it in steam at 120°C for 20 minutes. After that, the pure water permeation rate, rejection rate and θ permeation rate when treated with PEG water bath acid were measured under the same conditions as above. □ was measured. As a result, the pure water permeability rate ra, o:s9kazl/α7/・shi is above, and the P stop and G rejection rate is 69.5,
Water permeability 7 degrees 0; l 6? tr(1/'cy)r'・min)-2. It can be seen that the film treated with ν■ wet film recovered the performance of the original wet film.

□ For comparison 7), □ dry 11j obtained above! After immersing it in water for 1 hour, add 1. Measuring the force water speed is 2 J-rollers, 0.14. me7α7
Thirty-five minutes per minute is vaguely equivalent to the original amount.9.
The same membrane forming solution as in Example 1 was extruded into water from an annular orifice nozzle to obtain a hollow fiber polysulfone semipermeable membrane. / At the pressure of
5φ dried'EG water bath liquid to 1! //treated under the pressure of αd, 7′i! , when the rejection rate was 932% and the water permeation rate was 4.
517W at 5 hours. Process for 20 minutes and dry
``It turned into l.

The membrane performance is as follows: pure water velocity 1.98 e/n under the same conditions as
1. When the rejection rate is 92% and the water permeation rate is 46 e, /nl・hour, it is -7, is it correct? 7J J) It was the same as wet point j1.

For comparison, the above-mentioned dry JK was submerged in K], :dld
The pure water permeation rate measured under the same conditions as above for the bales soaked in Pt was 57CA113 hours, and the pure water permeation rate was 11T at a pressure of 2 kg/nl.
Ome/cn+, minute, 05% of average sweat size 20,000
Removal of PE () aqueous solution at a pressure of 2ky/lyn' i90
．． 2%, water permeation rate Q, l Q ytte/1yrf
・Polysulfone wet membrane with membrane property rrl'+ of 3 minutes
After soaking in 0% glycerin aqueous solution 1, dry at room temperature.
Shimata. Dry the resulting pattern; dry it in steam at 129°C for 10 minutes.
Disposal jj! Rewet with f4 L. The nature of the re-wetted membrane h'e,! ', j, pure water velocity IL under the same conditions as above
1.02 me/cytl, minute, I) )Il (
) For aqueous solution 9 C15%, water permeation rate 0.10 i
n7! /c+rf, minutes.

g) For comparison, the above dried membrane was immersed in water for one week and then measured under the same conditions.
0217 no IC/・]2 not t 1) a -
, Ta 0.5 noshi 1 ro9'li 汐υ , 1]"
Cho C Kosha Tai 2oop) I [Using, 11cz/c・tl
Jf-, pure water/Tsumeshi water rule 1i o, 4 in force 1
3 rne/(sod ・i), Prison~Ko B Ryoji-, 20
05 cycle of 000 Ph: o water soluble 1 i IY minute 7-1 and so 1) II'' focus 1''? Process 3j~/1-J when
Ji minus I + (81,1%, Shusui speed ia,: O, (1
9ml/ryrf, minute'I! J fl: rift
Prepare a wet V-force membrane using the following procedure.

After immersing the film in 30 liters of currant water solution, it was dried in a room (C1:・'/4). )), f
, after processing 7 and converting it to +'J餉Lr waiting 4, I set Iv)lJE fN correction to 1illi in the same article as in the second entry. 7 Replenishment water permeation speed - 1i1.45 + no I/! /(
Sono l″・zuha1) Removal rate 8 for l-Tamizu frI liquid
u9%, r1 water c (1 degree t, 1.10 m (!10zl
・Minutes - c6.

4C, V) i of 1 stroke, the above dry film was soaked in water 1 〼 1
Inter-immersion L A = r, same, obtained 4 (1) constant 1 - and pure water
11 minutes -, /ζ0 cow"j +5'l: Out 11
Person [1 Higashi Keiki Kogyo Co., Ltd. Representative Jukata Sanbu 51

Claims (1)

[Claims] A method for wetting a dry polysulfone semipermeable membrane, which comprises treating the dry polysulfone semipermeable membrane with pressurized steam at 100 to 130°C.