JPS5830309A - Cellulose ester permeable membrane and its production - Google Patents

Abstract

PURPOSE:To make membrane forming liq. much stabler and easier to handle in producing a cellulose ester permeable membrane by adding ammonium salts and water soluble org. liq. to the membrane forming liq. CONSTITUTION:5-35wt% cellulose ester is dissolved in 40-85wt% known org. solvent such as acetone and 5-50wt% water soluble org. liq. such as methanol, ethanol, ethylene glycol, glycerol or the like, and further 1-25wt% bromide, iodide, nitrate, thiocynate, perchlorate and acetate of ammonium are added thereto. The resultant liq. is cast and solidified and the ammonium salts are extracted away with water and other liq., whereby the cellulose ester membrane having excellent permeability is obtained. The viscosity of the membrane forming liq. is increased and the evaporation of the solvent is suppressed by addition of the ammonium, whereby the liq. is stabilized. The water soluble org. liq. improves the solubility of the ammonium salts and acts as a swelling agent.

Description

[Detailed description of the invention]

The present invention relates to a novel cellulose ester permeable membrane and a method for producing the same. Cellulose ester membranes have been developed since the invention of asymmetric lI for reverse & a

[Many improvements and developments have been made, and in particular, inorganic swelling agents such as metal salts and organic swelling agents such as formamide have been investigated. Furthermore, many techniques are known regarding ultrap-permeable membranes having a microporous network structure. However, the manufacturing technology of these membranes, especially the composition of the membrane forming stock solution and the conditions for maintaining the shape of the membrane after casting, have become to N and require a high degree of skill, making it difficult to apply as an industrial technology. I can say that I'm getting excited. In manufacturing a cellulose ester permeable membrane, the present inventor has discovered that a single compound can provide effective swelling action and pore-forming function.
As a result of intensive research into what was available, we discovered that ammonium salts have an excellent additive effect. We have also discovered that by adding a water-soluble organic liquid to the film-forming stock solution obtained in this way, the performance and properties of the film-forming stock solution can be significantly improved, and we have completed the present invention. It has arrived. That is, the present invention produces cellulose by casting a membrane-forming stock solution consisting of cellulose spray, an organic solvent, a water-soluble organic liquid, and an ammonium salt, coagulating it to solidify it, and removing the ammonium salt. It is an ester permeable membrane. and cellulose ester 5 to 35 wt%, organic solvent 40 to Bswt%, water-soluble organic liquid 5 to 50 wj%
This is a method for producing cellulose ester, which comprises casting a membrane-forming stock solution containing 1 to zswt% of an ammonium salt, solidifying it with a coagulating solution, and then removing ammonium. The present invention will be explained. Although there are few detailed reports regarding the solubility of ammonium salts in organic solvents and organic liquids, they can be dissolved in organic liquids of considerable range. Table 1 shows the solubility (room temperature) of ammonium salts. For 17 types of organic liquids, bromide, iodide, nitrate,
Looking at the solubility of the six ammonium salts of thiocyanide, perchlorate, and acetate, most of the combinations were soluble. Among these organic liquids, ethylene glycol, glycerin, and formamide, which are highly polar and cohesive, are soluble in all salts. Other examples of ammonium salts include chlorides, fluorides, thiosulfates, hydrosulfides, nitrites, sulfates, and sulfites. A feature of the present invention is that the addition of an ammonium salt improves the stability of the membrane forming stock solution, the operability during membrane forming, and the performance of the obtained membrane. Although the viscosity of the membrane forming raw material Rk depends on the cellulose ester concentration, it is generally easy to handle in the range of 100 to 1000 poise, and a relatively high viscosity is preferable especially when forming into hollow fibers. Addition of ammonium salt can increase the viscosity of the film-forming IfI liquid. It also has the function of suppressing evaporation of the solvent and stabilizing the membrane-forming stock solution. 5- [Revision 1] Solubility (room temperature), 3I or more salt dissolved in 10ml of liquid... Actual 1M not dissolved...・・× The added ammonium salt is extracted and removed by water and other liquids during or after membrane formation, and is considered to be a contributing factor to the formation of voids and pores in the polymer network in the permeable membrane. Membrane performance, especially solute permeability, is thus improved. The water-soluble organic liquid is a monohydric alcohol having 1 to 4 carbon atoms, a dihydric alcohol having a molecular weight of 700 or less, glycerin, and formamide, which dissolves ammonium chloride and also serves as a non-solvent or a non-solvent in the membrane forming stock solution. Organic; acts as a carving agent. These water-soluble liquids, together with ammonium salts, contribute to stabilizing the properties and increasing the viscosity of the stock solution, and are also equipped with the ability to improve membrane performance. Cellulose esters used in the present invention include cellulose butyrate, cellulose tri'-tate and
Celluse is preferred. Other examples include cellulose p-spurbionate and cellulose butyrate. The content of cellulose ester in the film forming stock solution is 5 to 35 wt%.
If the viscosity exceeds 7, it will be difficult to dissolve uniformly or the viscosity will increase.
-...0 2-1g...○ 0511 or less...△ 6- Too high to form a film. When the concentration is low, the obtained membrane tends to be fragile, but when forming a membrane on a porous support, it is possible to form a membrane even with a low concentration stock solution. In particular, when spinning hollow fiber membranes, the content is preferably 8 to 30 wt% from the viewpoint of spinnability and membrane strength. In the present invention, the ammonium salt is used by adding a small amount of the above-mentioned 1-5 salts (both 1h1) to the film-forming stock solution in the range of 1 to 25 wt%. Moreover, if it exceeds 25%, it cannot be added uniformly, and it will inhibit the stability of the membrane-forming stock solution or make the obtained film brittle.The amount of ammonium salt added depends on the stability of the membrane-forming stock solution, the membrane From the viewpoint of performance and film properties, it can be appropriately determined within the above range according to each film forming system. As the solvent for cellulose ester, known organic solvents can be used. For example, 7cetone, formic acid, acetic acid, methyl acetate. , ethyl acetate, caprolactone, dioxane, tetrahydrolff7ran, 6-methyl ethyl ketone, methyl alcorno, l-lifsetin, methylene chloride, dichloroporum, dimethylformamide, dimethylformamide, nitromethane, pyrrolidone, N-methylbi-lidone, dimethylformamide. The preferred solvent is methylene chloride (and methyl alcohol).
, acetone (and methyl alcohol), te)rahydrofuran, dimethylborum-7mide, ]-methylacetamide, N-methyl-rubipridone, dimedyl sulfoxide, sulfolane, and ε-cabractone. Methyl alcohol or ethyl alcohol may be used as an auxiliary solvent. From these organic solvents, a solvent that dissolves a predetermined ammonium salt is selected to prepare a film-forming stock solution. The content of the organic solvent in the film-forming stock solution is determined relatively from the other components, but if it is less than 4wt%, it is difficult to uniformly dissolve and disperse the other components. Examples of water-soluble organic liquids include methyl alcohol, ethylfurfur, propyl alcohol, butyl alcohol, cyclohexyl alcohol, ethylene glycol, diethylene glycol, and polyethylene glycol (molecular weight 70
0 or less), glycerin, and porumamide are preferred. The addition amount is preferably 5 to sowt%; if it is less than 5%, the effect of addition is small, and if it is more than 50%, it will hinder the dissolution and stability of the stock solution. For dissolution of the ammonium salt, it is sufficient to provide at least one of a solvent and a water-soluble organic liquid. As a method for forming the film of the present invention, known methods can be applied. A thin layer of the membrane-forming stock solution is cast onto a support (which may be separated from the membrane after membrane formation or may be combined with the membrane using a porous support) using a slit die, a doctor knife, or the like. The standing conditions (atmosphere, temperature, humidity, time) after casting are appropriately selected depending on the solvent system. In the case of a tubular membrane, the membrane is formed within an annular slit or a tubular support using a mandrel. In the case of a hollow fiber membrane, membrane formation A is performed using an annular (two-tube) nozzle or an arcuate slit nozzle. Additives such as inorganic cooling agents (silica, calcium carbonate, etc.) and gastroactive agents can be added during film formation to adjust viscosity and improve ring flexibility. The coagulating liquid is mainly composed of cellulose F, Chill 111 bath (ζ). This 014 diffuses and removes the solvent and water-soluble components from the cocoon layer and precipitates 1 = loose ester (coagulates). 1^1) Aqueous solvents, which are representative of non-solvents, are preferred.Coagulants such as salts may also be added to the solvent. Alcohol is suitable for preventing the formation of a fine dust layer on the membrane surface, and alcohol is suitable for use in preventing the formation of a fine dust layer on the membrane surface.
Since this is preferable, it is also possible to use a mixture of the two if necessary. When a non-aqueous coagulating liquid is used, it stops the coagulation and bends the additives and the body.
Generally, the final treatment is performed with an aqueous solution. The permeable membrane of the present invention can be made into a dry membrane using a known method, for example, using glycerin, a surfactant, etc., while maintaining its flexibility. In addition, if the pore diameter is too large, it may be dried as is. An advantage of the present invention is that a high-performance membrane can be formed from a membrane stock solution with a relatively simple composition under normal conditions. The permeable membrane of the present invention can be assembled as a module and used in ultrafilters, microfilters, plasma separators, etc. For example, ultrafilters can be used in a wide variety of industrial and medical applications. It is also suitable for operations such as recovery, purification, and concentration of valuable substances, and can also be applied when obtaining preparations from natural products or blood. In the medical field, it is used for r-type artificial kidneys, plasma separation (blood purification, membranous membranes), etc. The present invention will be further explained below with reference to Examples. Example 1 Cell p-sudiacetate (Teijin NH type. Degree of acetylation 555%, degree of submergence 170) 12wt (hereinafter abbreviated as "chi"), N-methylbrolyte (hereinafter abbreviated as "NMP")
(52%), formamide (26%), and ammonium iodide (10%) ;) Hit 9Ti:L on glass titanium with Dr.Nino, weigh 1゛ for 30 seconds under room temperature atmosphere, add Lingui coagulation liquid (hereinafter abbreviated as W) and 61:water/
Coagulation 1- by immersion in methyl alcohol (+/1) mixed coagulation solution (hereinafter abbreviated as M). Cow + fn clear fulbumin t, i,
1: Vibration [J purine before dissolving in water, membrane 141M1: water ultrafiltration rate (TJFR (ml/rrl-hr)
-m+nHg) ) f=; and bath'I! i transmittance (S
(%)] was measured. The 13 results are shown in Table 2. 2nd f, <0
This shows the results of two cases in which the coagulation liquid was changed. Comparative Example 1 A film-forming stock solution consisting of cell p-diacetate (16%) and N-methylpyridone (NMP) (84%) was prepared, and thereafter film-forming was evaluated in the same manner as in Example 1. The evaluation results were as shown in Table 3, and the permeation performance was low. Table 3 Comparative Example 2 Cell p-sudiacetate (12%), NMP (58%)
A membrane-forming stock solution was prepared from t and formamide (30%), and a membrane was formed in the same manner as in Example, and the membrane performance was evaluated. The results are shown in Table 4. Table 4 Examples 2 to 4 9 As shown in Table 5, Cell 1-Sziph'Sehut (12
F) and NMP (52%) growth conditions were kept constant, water-based organic liquid (26% each) and ammonium J
Film forming stock solutions were prepared with varying concentrations of M (each 10%). 116i was produced in the same manner as in Example 1 using methanol aqueous solution M1 pseudo-solid liquid. The evaluation results are shown in Table 5. 14-To Example 10-13 As shown in Table 6, cell lff-sudiacetate (
A membrane-forming stock solution was prepared by keeping the concentrations of 14LIJ) and setone (52%) constant and varying the concentrations of water-soluble organic liquid (26%) and ammonium salt (8% each). A film was formed using coagulation liquid M in the same manner as in Fire MII Example 1, and the film performance was evaluated. Table 6 Comparative Example 3 Cellulose diacetate 1.14%/setone bath solution was prepared.
When a membrane was formed in the same manner as in Example 1 and its performance was evaluated, almost no bovine blood-end fulpmin aqueous solution passed through it. Examples 14 to 17 Film forming stock solutions were prepared as shown in Table 7, and performance was evaluated in the same manner as in Example 1. Cel p-striacetate (Daicel 'JJ LT 15, degree of acetylation 61%, degree of polymerization 280) and Nitrocel p-s (R8-1 manufactured by Daicel)
20, nitrification degree of 12, and polymerization degree of 440). Furthermore, a methanol aqueous solution was used as the coagulation liquid. In both cases, the permeability of the membrane was improved by the action of the ammonium salt and the water-soluble organic liquid. Example 8 A membrane-forming stock solution similar to that in Example 8 was prepared, and after passing through and defoaming, the liquid was extruded from the two-wheel tube nozzle, polyethylene glycol 200 was discharged from the inner tube, and air was passed through it. The spun membrane was coagulated with a coagulating solution Ml'fM consisting of an aqueous methanol solution and washed with water to obtain hollow 412 KJ+.The spinning condition was good, and a semitransparent hollow fiber with excellent roundness was obtained. The dimensions and membrane performance are shown in Table 8. Table 8 Patent Applicant: Teijin Ltd. 20- Procedural Amendment March 23, 1980 To the Commissioner of the Japan Patent Office 1, Indication of Case Patent Application No. 1983 +26688 No. 2 , Name of the invention Cellulose ester permeable membrane and its waste manufacturing method I 3, Relationship with the amended case Patent applicant November 300, 1-chome, Minamihonmachi, Higashi-ku, Osaka-shi Teijin Limited Representative Tomoo Tokusue 5 Correction target +11 Q1 11!+, Mimi 1 it jl I'
Q! / 4 nth, lIR13L J (2) same, page 17, line 5, r ffl: , 1 is corrected to 1 type. (3) Delete 1-DMF=dimethylformamide in the 3rd line of [Note 5] under Table i7!7 on page 19. (4) 2nd line of [Note 6] under Table 7 on the same page,
1-E c: Ethylene glycol-l Delete all-j
7). Above 2-45

Claims (1)

[Scope of Claims] 1) A cellulose ester permeable membrane formed by casting a stock solution consisting of cellulose ester, an organic solvent, a water-soluble organic liquid, and an ammonium salt and solidifying it with a coagulating solution to remove the ammonium salt; 2) Zululose ester 5-35M tray%, Toiyu 7A4
o ~s swt%, water g Note a'lcj, body 5~5
oti = spear? 1. A method for producing a cellulose ester permeable membrane, which comprises casting a stock solution consisting of 1 to 25 anomonic salts, solidifying it with a coagulating solution, and then removing the ammonium salt. 3) Cellulose ester, cellulose diacetate,
The method for producing a cellulose ester permeable membrane according to claim 2, wherein the membrane is at least one selected from the group consisting of cellulose triacetate and nitrocellulose. 4) Cellulose ester permeation according to claim 2, wherein the ammonium salt is at least one compound selected from the group consisting of bromide, iodide, nitrate, thiocyanide, perchlorate, +6, and acetate. Membrane manufacturing method. 5) The organic solvent is methylene chloride, acetone, tetrahydrofuran, di-1'', dimethylform7mide,
Production of a cellulose ester permeable membrane according to claim 2, which is at least one compound selected from the group consisting of dimedyl/cetamide, N-methylpyrrolidine, dimethylformhoquinide, sulfolane, and cabrolactone. Law. 6) The water-soluble element 1iso liquid is 11+lli having 1 to 4 carbon atoms.
Alcohol, cyclohexyl alcohol, molecular value 700
Consists of the following divalent furfur, glycerin and formamide! The method for producing a cellulose ester permeable membrane according to claim 2, wherein the cellulose ester permeable membrane is at least one compound selected from 1f.