JPS5945334A - Preparation of microporous membrane of regenerated cellulose - Google Patents

Abstract

PURPOSE:To obtain the titled membrane useful for membrane separation, having improved strength, in a short time in high reproducibility, by using wet method wherein a cuprammonium solution having a cellulose molecule with a specific value of average molecular weight is cast in an atmosphere of vapor of an organic solvent, and the film is immersed in a mixed solution containing an organic solvent. CONSTITUTION:In preparing a membrane from a cuprammonium solution of cellulose having >=5X10<4> average molecular weight, it is cast in an atmosphere of vapor of an organic solvent containing one or more organic solvents (e.g., acetone, trimethylamine, etc.) having <=100 deg.C boiling point, >=10wt% solubility in water, and no OH. After minute phase separation is occurs in the cellulose cuprammonium solution, and before the dilute phase after the phase separation is made to flow to the surface of the film, the cast material in a state of the minute phase separation is immersed in a mixed solution containing one or more organic solvents having no OH, having >=10wt% solubility in 28wt% aqueous solution of ammonia, not swelling cellulose, to give the desired membrane.

Description

[Detailed description of the invention]

Water valve 1 light is born cellulose (・j (1 to y4 method of porous membrane)
91. To explain in detail, in this defense, cellulose (11 types) is melted (1-0 in a steam atmosphere).
1 ILshi, then Ijrou melt 4'i11. ? This invention relates to a method for producing a new microporous cellulose cellulose by a dry-wet method using a mixed bath lrk K. Membrane fraction technology is attracting attention among the materials technology. The temperature change due to the separation of Ida-dome and Tokinari is set as IV・”;1, there is no, there is little energy that is inevitable in minute 11
4) The special feature of the 1iii'1 separation process is that
;7. Taking advantage of this, the polymer 1tIi!- is used in the fields of wide QiiΣ11 (1). For example, dairy farming, fisheries, city hY-1 food processing, 15 medical products, chemical industry, textile dyeing processing, iron. 41. Machinery, surface treatment, water treatment, atomic crab industry, etc. As a field where the stem is central, fjl ii is i&+, ('')
Shrinkage at low temperature, Japanese made, 11g per time '5: Necessary amount!
l8J (j (products, biochemical industry) (ri + 7i, p ≧ must be four and -4! I! j (pharmaceuticals and oil power; Tekimon, electronic industry), (, j) imitation 'lr of the most expensive material
',! 1Iili recovery (nuclear power, 'jl + metal field),
■Special minor, 4/separation field (non-medicinal! 4!r), (QJ
Engineering xy /I/Ghee-rich %I4. min #, ij min! Jt
(alternative to distillation) is possible. The membranes to be used for these '3'F's must be hydrophilic with large pores and easy to handle. As a method for producing pores of 1%f made of cellulose, which is a typical example of a hydrophilic polymer, there is a method in which an emulsion of kerosene or the like is completely mixed into a cellulose copper ammonia solution to create pores of +11y. The porous membrane produced by this method (4) has an average pore diameter of 1 μmlJ or more, but the pores are non-circular and form a layered structure, making it extremely brittle. However, the solution is unstable and it is difficult to re-form the film industrially to JΩ. Just by mixing a non-coagulating liquid into the copper ammonia solution and making it into the coagulating liquid? ,) Let's make it hard,; + let it be porous! In the method for manufacturing IJI-2, the pore diameter of the obtained porous IJI-2 is 0.
．． 0111 m or less, the overload property is poor. It is still known to produce regenerated cellulose porosity 1 by saponifying cellulose acetate fat conductor porosity in an alkaline water bath. In this way, the average pore size of the pores r1 'ri+・t;・,'3.5X10'
It is as follows. Perhaps this lower molecule'rrl
/If this is the cause))'C explanation, but it's dry 7. I
Mechanical properties of porous membranes at J< (especially strong II is markedly I
J (lower and brittle. For example, the pore diameter of the pore 1 ψ is Pr (%) and the externality 1' of the pore 11 ψ)
1. J? l is 106 (10U-Pr) Sdyn/c1n
The strength +8' in the wet state is even lower than that in the dry state, so it is the best that can be obtained from a cellulose-packed conductor (the regenerated cellulose porous membrane from rY has a
It may be damaged at times. ζ et al. have the disadvantage that the preparation process is not r+ and is also expensive. The first erection characteristic of the method of the present invention is that 811 points are below 1()0°C, and the solubility in water is below 10 degrees.
And no k f'i'1 prefecture, flowing under a solvent vapor atmosphere, this /iti', 'ij! E, the cellulose explosion 1 ammonia solution has a microphase content 1i;
After becoming It-like j, IJ,', and before the dilute phase generated when the microphase content = V leaches onto the membrane surface, 28iJi, which has no water monomorphic group and is at 20°C, 1. :
The cellulose is immersed in a mixed solution containing an organic solvent whose solubility in an ammonia water bath solution is 1% by weight or more and which does not cause the cellulose to swell to 1%. Whereas the pore diameter of a porous membrane produced from a cupric ammonia solution of cellulose by a conventionally known method is 0.0111 m or less (4), the pore diameter of a porous membrane produced by this method is 20 μm from O2O3.
The porous membrane has a pore diameter range of V, and the number of pores is increased compared to known methods, and there are many through holes. Here, microphase separation means a state in which the OR phase or dilute phase of cellulose is divided and stabilized as particles with a diameter of 0.01 to several μm in a solution. Arisuzoku // U atmosphere 1

[By forming a film, porous ++iy, surface A <'JF [[
11Q This student 1j (') is eliminated, and pores with a pore diameter of 001 μm or more are formed on the evaporation surface. Force Il!
IIl', 1 In the atmosphere, as the concentration of the solvent atmosphere increases, the pores of the porous 1-hole +1S also become thicker, the number of holes decreases, and the 11-curved hole also becomes larger. Therefore, it is desirable that the layer (dispense of solvent vapor is not less than 50 layers of t11 and t11) is cast in an atmosphere of organic solvent vapor, and a solution of cellulose in 1161 ammonia forms a microphase. minute 1
I;
! +Before leaching onto the surface, there is, -slang) jl, 1
．． Game meeting 21+': G' Biao From Riko who soaked the seedlings in the liquid, mixed ↑ Mei 71 & inside (here (1□j and 7 not) Compared to the deception, Kong Xiang became even more popular, and Kong The number also increases to I, the number of 51 curved holes increases, and the number of B+ decreases.Therefore, the water in the mixed solution 7rt
7t μIW of 1z ammonia is 02 heavy duty”-1J
'ITj' j, i size or less, and foam dissolution in water I; 5? ? -Jinol'ka l U 1i (4 pieces 1)
Above, 7 (middle) - G] which is below the 94th preference. Here, - Cell T course Kanai 7 = ill Rakusei Zenai W 4
Atv mol J, 'ic and 6-j 4) F i, 01)
Cm-5 horizontal 1.0 (1(fll's (4/lz+, J-
Su a hole +p 17. The J 4m yfi medium” 2
” ℃ for 1 () minutes, 11);
1 death 1. t15~0.97 cms l'M 1.05
〜0,97 tyn 4・; (means all solvents. ゛Also, cellulose in front of flow) 111 ammonia solution M
Place the good stopping solution iζjQ in the group or 30M.
By doing F% Naudo's b brilliance + ('Shinyoku 1 in size'),
4(j, +7! time) can be reduced to 1↓, and the number of steps in the process can be easily reproduced by 1↓. It is clear that the 1jc-i becomes devitrified when it is formed in a solvent vapor. That is, in the method of the present invention, the microphase is devitrified in the organic bath 14<, 211i. The father that generated the molecules, microphase separated pi, j4 f promotion M (making E 11ik R: t!%' to -j', -tJ water IYi liquid, and then solidified regeneration treatment There is a special edge at the point V that makes the difference 1.If the micro phase component 11+ occurs,
Li! ] Fleshing I11. !
,・, J-sensing furnace,・a) Or the membrane 't' after milling,
It is confirmed that there are particles with a surface diameter of 1 μm or more from the thin 1' Shishikagami ~ type rC, i? -! a. Such microphase molecules ry
The presence that causes ′? As a τ medium, 9j, water 1) put out 4 sets of SE, the size is 28 times), 1' ammonia aqueous solution 11
It is essential that the solubility in i4 at 20° C. is 10% or more and that the cellulose is not saturated. In the method of the present invention, at 1F, it is determined whether or not the solvent vapor to be used under the 4-way flow is determined.
? , town f) J, j's springing point is Le Mutsu. boiling point is 10
At temperatures above 0°C (under the atmosphere of solvent vapor) 1, microphase separation does not occur and a transparent film becomes a transparent film, or Δ
・) Rui is lit, '2 layers are formed on the surface, and the holes on the surface are 1 night & 10. (11 μm or less. Therefore, the lower the boiling point, the better, but from the 7th step of controlling the manufacturing conditions, it is always above +111 fIcAI. Also, the boiling frequency of the mixed tube jl containing the organic solvent is :・Solution Iha(is a water roku group or not?・is 1■@woman・i)ru, water i'!> AI-money owner 1'j 4j,"' B+ 'A': ' cTl
``;'2' tr ?f'A in the midst of - Ck, the microphase molecule ril [irJ:) 1 myself, ga, 1 and 1 film - become 〃j, or Q'' 11 coma Skint on its own, the force is like a cow, or it solidifies in the shape of &, L-')",
As a result, the hole I<1ri+, '15(rj 0.01
Less than μm°. Ki Noboru, 1.1) 1 way i') -: "L can be used A'"
l+medium, C air C7y Iishi, bottom and mountain ＼ Gosei 11 Yuko de Li) 11 published edition (some solution + 71's'no' as 'll, ri 1 nzu ↓ J or isi ↓ 7 min For example, there are acetone, methyl ethyl ketone, trimethyl amine, etc., in which the Q molecule 1' is small (
If! #t)tl (1) (V 4ai'i and
1.5 place 1 Koko J'a (M li:il, endogenous, ('
I'C11", *, 7 tl4 J 1.t: d) Tenno's creation - 'r items and desirable,, nafu,, the ij?i'i
Solvent's 28-year-old's An 1-year-old water f't': 71!
', to fi;j'r'fim''< ■ at 20 °C
Mountain jit'% Anne Sevenia water melt late IU Ornl this melt 1! i'l'7l-ir':'(,ft,' (skewer, +J)) KAJ Osi h; 1゛J上-C
i IrjtLrl, micro-same course...:il don't shout no Σ, or IIA! The surface of
′;J (I-J' U, J', 0.01 μm or more. Dissolution of water) 1+'61! , otherwise the trade would be difficult. 2. In the present invention, paulownia ammonia (r) is a solution containing copper and ammonia as main components, and is a boiled oil solvent called Schweitzer's reagent. , WIJ method of dissolving cellulose (-Kiru melt θ111 system, (1, taste, cations other than copper Δ・) or partially mixed with solvents other than ammonia are also included. The second feature of the present invention lies in the use of a copper ammonia solution in which the average molecular ridge of cellulose molecules is 5 x 10 or more.
The strength of I is 1M', the soil is washed, the filter is improved, and the porous 11
・Handling of η becomes easier, and porosity damage itρ14 is reduced. A conventional cellulose material (such as cellulose acetate) is dissolved in a solvent, and then [&-L,,
In the method of multiplying (1,111) Ii7c, the molecule (!P beg, 5xio' to "double e", is almost obsolete. Frog] ammonium r solution 71'j 'c flight river use By doing this, it is possible to prepare a cellulose shell of the polymer ttF'VjlJ.For example, if the porosity of the passage holes 11 and 4 is
q6), the deflection of Izliil bone 4 obtained by this method J15×10" (100-Pr) dyn/
It is z2 or more. cell. The average molecule 6 (ka) of the average molecule 11j of the -vacancy molecules is larger, the failure rate of monopolymerization compared with the same -vacancy bar decreases. as,
As the average molecule i,l becomes larger, there is a tendency for n to become shallower11, ? ! I can't stand it. Therefore, even if the average molecular weight is 5XIU'2 or less, it does not matter from the point of view of practical ease of handling. Once the cellulose in the casting solution reaches 5%, IIζ! The thickness is controlled internally, and it is difficult to create a porous iP with good reproducibility in manufacturing. When it exceeds 10', ij, hJ, IiNα becomes hard and transparent, the porosity decreases, and the number of pores also decreases. Therefore, if the cellulose ratio is 5% to 10%, it means that the performance as a practical porous membrane is 10)/i#'4hi. However, cellulose CI, 1 degree here means cellulose in copper ammonia liquor @: 1) hood 1F, 111. 'L
, After the cellulose steel ammonia solution undergoes microphase separation, 1% is added to the acetone/ammonia/water mixed solution.
However, if it is regenerated by deoxidizing it (FC, for example, double-layer single-phase sulfuric acid) and then sandwiching water between wooden bales and an organic solvent with a boiling point of 70°C or less, the number of pores will increase and the vacancies will be removed. The porosity has also increased, making it look even more feminine. In addition, the ratio of ammonia to water in a mixed solution of acetone/ammonia/water is 11. ．． 11 degrees is 0.2 times 'IJi-
% or more and 3-, ffk % or less, and it is most desirable that the CM of acetone with respect to water is 15 times or more and 65 times or less. Furthermore, water 'c iR! As a result, the production time is further shortened, the number of pores in the obtained porous membrane increases, and the porosity also increases, and the filtration performance of the porous membrane becomes better. +S as t”,
Although it is not specified, it will be collected (r,!,
)t:? Takekako L・Ah, then iiM (If tR
is used. ! (), the porous film prepared by the method of the present invention has pores created by the force of the microcrystalline molecules,
11. Eyes that do not contain air holes. The point that there are few uncles of i is given (higher marks).
is much larger than the traditional one. The porous pores obtained by the method of the present invention can be used as a separation target for fractional removal of target components in a liquid or gas mixture containing water, even if it is artificial. Examples include artificial elbow I + rudder, and artificial elbow k ft-1 + i1. Other limitless songs ii4 it%! Use it as a bow almost every minute! Although it can be used for 1.11.I, it is hydrophilic and mechanically compatible (1.11.I) is particularly suitable for bio-related fields (medicine, biochemical industry) or food fermentation fields. 715 on the 14IQ structure of the membrane obtained by the method of the present invention.
In a typical example of characteristics and each A medium value, the average molecule fij of cellulose molecules is 5.8 1. OX ] 09' F n/1rn2,
Peak value of mechanical deviation (plow δ) (bu + δ) lna
X is (1.2 or more, average pore diameter is 0.2 μm, porosity &;
t6) i%, hole 4X & J: 9 x 10 pieces 1
It is 0n. implementation? Prior to 11, the method for determining the physical properties of 1 night, which was used in the detailed explanation of ψ4, is shown below. To the average molecule (〉 ≦ 110 By substituting the 4-finite viscosity 18' 〔η) (ml/9), which was determined at 8:11 in ammonia valley solution (20℃), into the formula (0), the average molecule can be calculated. ;i (viscosity average molecule) 7) Produce a large amount of Mv @Mv = [η:]X3.2X1
03 (1)〈(visit 1δ) max, dynamic elastic modulus〉 A strip-shaped sample with a width of 1+tm and a length of 5 mm was cut out from the porous membrane, and a Rheo Vibron manufactured by Toyo Pole Dough 4F Co., Ltd.
Using DDV-nc type, measurement frequency 110Hz,
Under dry air, the Peng δ-temperature curve and the dynamic elastic modulus-temperature curve were measured at an average heating rate of 10° C./min. From the measured tan δ-temperature curve and dynamic elastic modulus-temperature curve -
Read the peak value of δ (t, LLIδ) max and the dynamic elastic modulus at 30°C. Average pore radius and number of pores> If the number of pores with a pore radius of ry r + dr per 1 ctn of porous membrane is expressed as N(r)dr, then (N(r)
is a pore diameter distribution function), the average pore radius T3 and the number of pores per unit N are given by equations (2) and (3). 1L) N "type 11i', child!" l i'('jm k using table name hole 1:! a's name 11.; child 4 ((・1: table copy AχJi + 4 shadow. 1 ,7ヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヱヽ,N
) k R out, C! i-k (2) Substituting into the expression, in other words, the bill tithe fJ'4 and the desired fil (minute's run J-υ'i41.child 37.1ii change p1'f 77-
Sada, make a suitable size, for example 20cm x 2fl
cln) and enlarge it and print it! Draw a total of 2 (2) test lines (placed pieces) at equal intervals on the plagiarism sheet that was drawn. 474, (,7,) to measure the merit of the man who exists in the hole when one hole of the deceased is one.
i' L , find this frequent 1+i distribution 1'jI'<9. This cheek 113' distribution [(%l
l: "Quantitative form p, ¥: Gaku" harmonic Ni store) direction θ2 is N
(rl %: Determined. <Porosity Pr) Planar multi-I, Ill, ii bubbles - LJI emerges in the shape of a circular hole with a diameter of 47 [7, the pores II! Fu'AIT soldiers dry in the air to reduce the moisture content to 0.5% or less. Pore after drying 11. lj; IEi' of L is d (,,), weight 114
If Wf is 91, the porosity is given by Pr (+4 for the hook) and is given by the formula <strong elongation rJt'> Toyo Ball Umono Weir TENSIL
Using ONUTM-1I20 type tensile tester, 20
°C, (O measured at a tensile speed of 50 mm/min under the conditions of 0% RH) The present invention will be explained in detail below by way of examples. Examples 1 to 5 Cellulose linters (average molecular weight 2.33X) (15)
Ai'd IV was carried out using a known method (in which ammonia was dissolved at a concentration of six layers during melting). Cast onto a glass plate using an applicator with a thickness of 300 μm at a speed of 0.2 m/min. In a mixture of acetone/water and ammonia/water fr'4 nY (2
0℃) for 15 minutes, then soaked in 2% sulfur r + θ at 20℃.
After soaking in the aqueous solution for 10 minutes, washing with water, and then blotting with moisture 'f-P paper 1ν[,2o1? Rinse the shellfish in acetone (1o (l tu%)) for 15 minutes to remove the moisture in the shell, and place it on paper at 30°C with Mr. & J. Examples 6 to 10 Cellulose linter (average molecular weight 2.:33 x 10
5) was dissolved in a copper ammonia solution prepared by W.
,Ta. The solution was applied onto a glass plate with a lid length of 3 (0.2 m/cm with a 10 μm applicator) in an acetone vapor atmosphere at 30°C with a concentration of 80% of the saturated vapor pressure.
It was cast at a speed of 1 minute. It was confirmed that microphase separation occurred on the casting #I surface for 8 minutes under the atmosphere. In addition, this neglect 11.1. Between 7' and 7', no dilute phase leached out on the IIQ surface. Mixed bath A# with 0.8 weight
(20°C) for 15 minutes, then soaked in 1ilS2()°C for 10 minutes in 2-ichi sulfuric acid solution, rinsed with water, then blotted with water, and soaked in 20C acetone. (100 type set %) Il, 6r ■ for 15 minutes,
Remove the moisture in JBJ with acetone and place it on a filter paper.
Dry Jj・(f(,oc!'y) at 3()℃ with Mr.
19% does not show the characteristics of the porous membrane A obtained.
) was dissolved at a concentration of 6% in a 1% ammonia solution prepared by a known method. Acetone (10
0 Near 1 Jir % (
-, i! -, ) + t), press, punch, and apply the solution to a thickness of 'J' on a glass plate in an atmosphere of acetone vapor at 30°C with a saturated vapor pressure of 41 JIF and 80 cm.
31) Casting was performed using a 0 μm applicator at a rate of 0.2 In/min. After leaving it in this atmosphere for 5 minutes, it was immersed for 10 minutes in a mixed solution (20°C) with an acetone/water ratio of 336% by weight and an ammonia/water ratio of 0.8% by weight, Then, at 20℃,
After soaking for 10 minutes, wash with water, absorb the moisture with r paper, mash for 15 minutes in an oven at 20°C, and remove the moisture inside. 1 city, (
Place the sushi on a filter paper using a 7-inch knife at 3()℃. Shita. I (Smooth porosity 1 + = characteristics of all vehicles I Jak V are not shown. Second! IJ2 Cellulose linter (average molecule (d″2.:33
105), 11.j1 ammonia? ? (6% (tI',: I had a foil rhinoceros) in the liquid. The Δi7 night was 30℃ of methyl ethyl ketone in the shell of a gas atmosphere) W or saturation 1 vapor pressure 75 factor 41
It was spread on a glass plate to a thickness of 30 (J μm) at a body temperature of 0.2 n+/min under an ambient atmosphere for 8 min. 'l il・
After 1', the methyl ethyl ketone/water ratio is 33.6 parts and the ammonia/water ratio is 0811j bf
% mixed solution (20°C) for 15 minutes and J7+'f, then immersed in a 20°C 2% aqueous solution of carcinic acid for 10 minutes,
I bought 117A of water + tl-,, L Karu's waterproof outside for a fee of 117A, and 1 in Architon (10 (l city, 5 Ychi)) of SOOC.
Immersed for 5 minutes 6t L, , water molecules in the membrane - r setone to 11
5+133 Cellulose linter Next average molecule 1 (12,33X 10
5) While synthesizing cupric ammonia prepared by a known method, the solution was heated at 30°C.
The methanol vapor surrounding atmosphere must be 3()08 thick on a glass plate under a 75 inch pig enclosure with a vapor pressure of 1ii5 and 11.
Q with an applicator of m, Ml at a speed of 2 m/min,
It was extended. After being exposed to the atmosphere for 8 minutes, it was poured into a mixed solution (at 20°C) with a methanol/water ratio of 33.6% and an ammonia/water ratio of 0.8%. After that, it was immersed in a double-acid aqueous solution at 20°C for 10 minutes, washed with water, and then all the moisture was absorbed with paper, and the mixture was soaked in acetone at 2°C. (ilOj4j
hi%) for 15 minutes and il! The properties of the porous membrane are shown in Table 1. Example 14 Cellulose Link - (Average molecular year-2,33X it)
6) in a cupric ammonia solution prepared by a known method.
, '+%% once again. Part 4 - Amount of liquid ke 3
Bacterial blood in an atmosphere surrounded by acetone vapor at 0°C is applied to a glass plate with an applicator 30,011 m thick under an atmosphere of 80 cm and a saturated vapor pressure. :l 0.2 m at a speed of 7 minutes IW
It lasted a long time. The acetone/water ratio was 33.6%, and the ammonia/water ratio was 1-1; After applying the IUI tube for 15 minutes, the sample was immersed in a dichloromethane aqueous solution at 20° C. for 10 minutes, washed with water, and then sandwiched between filter paper and air-dried. Table 1 shows the properties of the porous membrane obtained. Incidentally, a scanning electron micrograph of the front surface of a typical example of the membrane obtained in the above example is shown in FIG. 1, and a standing electron micrograph of the back surface is shown in FIG. Margin below

[Brief explanation of the drawing]

FIG. 1 is a scanning electron micrograph of the surface of a porous membrane obtained by the method of the present invention, and FIG. 2 is a scanning electron micrograph of the back surface thereof. Patent Applicant: Asahi Kasei Kogyo Co., Ltd. Patent Attorney: Akira Aoki, Patent Attorney: Kazuyuki Nishidate, Patent Attorney: IB Yoshio, Patent Attorney: Akira Yamaguchi Figure 1

Claims (1)

[Claims] 1. A method for forming a film from a copper ammonia solution of cellulose having an average molecular weight of 5 x 10 or more, wherein the boiling point is 100°C or less and the solubility in water is 10x fr8' 1 or more. and is cast under a polysolvent vapor atmosphere containing at least one type of vapor of an organic solution W that does not have a hydroxyl group,
After the cellulose cap ammonia solution undergoes microphase separation and before the diluted phase fraction Aft flows out onto the membrane surface, it is converted into an ammonia aqueous solution having no water groups and having a weight ratio of 28%. The melt tW ICF is 1 +l Nail Ji
regenerated cellulose, which has a total inclination of 100% or more and that the microphase-separated cast product is mixed with a mixed solution containing at least one kind of solvent that does not swell the cellulose. Manufacturing method of microporous I11;>. 2 A 1 solvent ke, below the gluing point or 3 () chill...
Fukui! , in the dark IW+ below, is it applicable? 1. The method for producing a regenerated microporous cellulose membrane according to item 1, characterized in that the membrane is added to an ammonia solution. 3. Claims Nλ1.1i characterized in that the degree of cellulose consistency is 5 to 'Oj-ti,', i
'4: P, Q, regenerated cellulose (L) of V described in item 22
Yuuta ti'if! 4-M method. 4. In order to form a film from the starting ammonia solution of cellulose with an average molecular t of 5 x 104 or more, the crude ammonia solution of cellulose is cast in an acetone atmosphere, and the crude ammonia solution of cellulose generates a microphase component +r:++. After that, and before the dilution that occurs during microphase separation appears on the film deposited δ],
In a mixed solution of acetone/ammonia/water [the cast material is immersed and then treated with acid]'lli L, after washing with water 2, it is porous with a boiling point of 70°C or less. Claim μl'12 characterized in that water in the frame is replaced.
P: A method for manufacturing a microporous bovine cellulose membrane according to the second term. 5. Claim No. 4311 R1 RQ raw cellulose i.
Manufacturing method of 11'A.