JPS5894862A - Selective semi-permeable membrane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a selective semipermeability 11, particularly for high-performance treatment of low-voltage body fluids in which the ultraf-pass rate and the selective separation of substances do not change even during long-time r-pass operations. This relates to a phase-selective semipermeable membrane.

In the past, various semipermeable membranes suitable for blood processing, such as hemodialysis, blood filtration, plasma separation, and plasma purification, have been proposed and put into practical use.

Such semipermeable membranes are often cellulose-based, but recently a synthetic polymer WA4 has been developed, but in any III, the ultrafiltration rate during the filtration operation increases the filtration time. This has the disadvantage of a change in the rejection rate of the fractionated space or the amount of permeable solute. Ultra Fj due to the large 11 membrane filtration time @ filtration rate of 19J after special KF far operation
There has been a significant decline in arrests, etc.

In practical terms, Urgent Research III is ugly. The cause of keratin is lamina K.
It is presumed that this is because concentration polarization occurs on the membrane surface during Fm* production, causing 11, and the filtration operation has been devised.

The present inventors determined that the ultrafiltration rate and the filtration time of each membrane,
After conducting a detailed study of changes in the amount of S-transfer electrolyte, it was discovered that the effect was more likely to be due to the membrane structure itself than to concentration polarization, which had previously been thought to be the cause. The membrane consists of an active layer that has its own separation function and a support layer that supports the scissors active layer.
The active layer changes from a dialysis membrane or reverse osmosis membrane to an ultrafiltration membrane or a filtration membrane. It consists of a quality structure. Some dialysis membranes and membrane filtration membranes consist only of an active layer. A membrane composed only of the active layer shows little change or decrease in ultrafiltration rate etc. with the filtration time, and the ultrafiltration rate, etc. changes or decreases little with the filtration time. The decline in continuous changes, etc. is significant. It has been found that the cause of this is l1llI& at the interface between the active layer and the support layer. In other words, the larger the difference between the pore size of the active layer and the pore size of the support layer, the greater the change in the ultrafiltration rate ♦ with the above-mentioned P hour. The phenomenon is presumed to be similar to the compaction observed when operating a reverse osmosis membrane, which is high-pressure filtration.

Therefore, the present inventors discovered that the boundary structure between the active layer and the porous layer, which is the support layer, is such that the pore diameter of the porous layer successively decreases toward the active layer, resulting in a large IF structure with the same fractionation as the active layer. The structure made of slanted porous w structure in contact with the active layer is the above-mentioned f.
We have discovered that there is little change in the ultra-PIiIll speed, etc. with the passage of time, leading to the first invention.

In the present invention, the active layer determines the function of the membrane + JjIJ, and in order to increase the ultra-F fluctuation, it is desirable that it be thin so as not to impair the separation function.
It is preferable that it is 01 to 10.0≦. The support 1 exists in Rin to support the active layer and maintain membrane formation, and in order to increase the ultrafiltration rate etc., the higher the porosity, the better! I
The thickness is preferably 40 to 99.1-.

The slanted porous III structure basically does not have cavities of 4F, and is an aggregation of pores that successively become smaller from the porous layer to the active layer. 7. Observation is done with a transmission electron beam mirror. Goo~ts, magnify ooo times.

The thickness of the graded porous II structure is preferably 0.11 to 50% of the film thickness, and the active layer has a specificity of 1, for example, several A to 1.
The number of liters is 10 to 100 times larger than the average pore size of 0μ.
A thickness of 100 μm to 100 μm is desirable.

Regarding Kaburashamaro porous Ill structure, it was shown in Japanese Patent Application Laid-Open No. 49-90684 that a membrane without an active layer can perform filtration for a long time without causing any knots. Having a layer is essential for maintaining the function of the membrane, and the present invention requires an inclined porous structure between the active layer and the support layer.

Specifically describing the ultrafiltration membrane used for blood filtration, the pore diameter of the active layer is from several to several hundred micrometers, and the pore diameter is from several hundred to several hundred thousand on the molecular edge, and the i1+thickness of the active layer is Saki
Approximately Ot~1μ is preferable, and the total film thickness is 01~10μ.
% column is preferred. The moth-oblique porous tSa region is a boundary connecting the active layer to the porous support layer, and i1! from the active layer to the support layer. Subsequently, in the region where the pore diameter gradually increased rapidly,
Exists in a width of 30μ.

The thickness is preferably 0.5 to 50 times relative to the entire film thickness. In this region, there are no pores having a size larger than that present in the support layer.

The support layer consists of a network structure composed of pores with a pore diameter of several hundred μm or more, and there are spaces within the 9wI network structure that have a pore diameter of S to 30 μm, which can be said to be cavities or voids. Good too.

The membrane material of the present invention may be a natural or synthetic polymer, but cellulose-based materials have excellent moldability into semipermeable membranes. Synthetic polymers are advantageous for imparting special mechanical purity, and hydrophobic polymers in particular have excellent water permeability, and can be determined depending on the purpose of blood treatment. Among them, acrylonitrile-based polymers have excellent chemical properties such as chemical resistance, and also have the characteristic that they can easily be obtained with water permeability or ultrafiltration rate of 1 tablespoon. Among the polymer positioning type combinations of seed blue, the acrylonitrile polymer is the one with the least change in ultra-Pa rate, etc. with filtration time among the membranes made with * above. ! Among atarylonitrile polymers, acrylonitrile and pentahydroxyl groups, carboxyl groups, and aturbid groups.

Sulfonic acid group, ethyl ester group, methyl ester group,
It consists of a vinyl monomer having a functional group other than a cyano group such as an imide group, and is particularly composed of 80% by volume or more of acrylonitrile, a carboxyl group, a hydroxyl group, a! ) group, methyl ester group, ethyl ester group.

An acrylonitrile polymer containing 20 vt% or less of a plurality of vinyl monomers having a sulfonic acid functional group is preferred. Even more preferred among them.

Acrylic nitrile 85vt or more, carmexyl group-containing H
Vinyl phosphor 1.0-10wt%, methyl ester group-containing vinyl monomer 5.0-10wt%, sulfone i
Group-containing vinyl monomer 0.1-1. It is an acrylonitrile polymer consisting of four components with Ovt%.

The shape of the semipermeable membrane in the present invention can be a flat membrane, a tube, a hollow woven shape, etc., and a soft, spherical, plate-like, thread-like adsorbent, and a surface of a porous body. Preferably, the covering body is in the form of a hollow woven fabric, since the effective area of the membrane per area can be increased.

In detail, the constituent components of the membrane material according to the present invention are acrylonitrile-based polymers, which have the properties, physical and chemical properties of acrylonitrile-based polymers when performing blood treatment, and are suitable for film formation. There is a need for a membrane form and membrane material that has good affinity with blood without impairing its properties. It is more preferable that the membrane material has a vI component, has acriminitrile of 80 wt% or more, and is composed of a hydrophobic co-I#mer and a hydrophilic and ionic comonomer in a certain proportion. I discovered that.

More specifically, the hydrophobic comonomer is vinyl Ml having a functional group such as an ethyl ester group or a methyl ester group.
A filtrate is preferable, and the wood-philic and ionic comonomer includes a hydroxyl group, a carmexyl group, and an amide group.

A monomer having a functional group such as a sulfone group or an imide group, particularly a hydroxyl group, a carmexyl group, or a sulfonic acid group, and is preferably composed of four monomers including acrylonitrile.

In the present invention, the rate of change, particularly the rate at which the ultra-Pi continuous and * quality permeation speed changes over time during the filtration operation, and particularly the rate at which it decreases, is expressed as the retention rate. What is the retention rate of ultra-P permeability? Measure the amount of ultra-P permeate for 30 minutes after starting the ultrafiltration operation, calculate the ultra-filtration rate after 30 minutes, and calculate Fj! After operation 2
Calculate the ultra-high Pa density for 30 minutes at 30 minutes from 70 minutes.
iL, calculate the ultra-P overspeed after 30 minutes,
The ratio of the latter to the former is expressed as a percentage. The retention rate of the solute permeation rate is F11 transient and is expressed as a percentage of the ratio of the solute permeation rate after 30 minutes and after 300 minutes.

In this example, the filtration operation was performed using fresh blood, and inulin was used as the solute. The hematocrit value of fresh blood is 38-42 and the white matter is 5.6-6.2 P/dl. 60 hollow fibers are bundled and both ends are wrapped with about 2 clI epoxy I.
A material with an effective length of 18 am was used that was cured and bonded with IIWI.

Actual example 1゜Acrylonitrile 93.1%, methyl acrylate 6.3
%, a copolymer consisting of sodium methallylsulfonate OSg was dissolved in 67.0% nitric acid to prepare a solution having a co-mineral concentration of 15.5%, and the defoamed solution was added to the spinning stock solution. did. This spinning dope was fed to the annular spinneret at a speed of 18 m/m, and the temperature of the spinning dope in the spinneret was set at 14°C. Water was fed into the center of the annular spinneret at a rate of 1.2 sd/m. The hollow fiber, which passes through an annular spinneret and encloses water in its central part, travels vertically downward in the air for a length of 15 mm, then coagulates in a coagulation bath and is wound up at 49 m/m. The coagulation bath is 30° C. water containing OtS nitric acid. The dimensions of the annular spinneret are as follows: the inner diameter of the cavity in the center is 0.1SWII, and the inner diameter of the capillary through which the spinning dope is extruded is oasm-.

The obtained hollow fibers had an inner diameter of 200μ and an outer diameter of 300μ.

The membrane thickness is 50μ, and the cross section of the III structure has a dense active layer on the inner and outer surfaces of the hollow fibers, with a thickness of 0.1μ, and the outer surface has a slanted porous structure with a thickness of 20μ. It existed. The inner surface side has an active layer with a thickness of 01 μm.

A slanted porous structure was present at 5 μm, and the remaining portion served as a support layer, which was made up of a porous layer containing cavities (611 diameter cavities).

The hollow fibers obtained are ultrafiltration membranes and are used for blood filtration. The change over time of the permeability of inulin as a solute with respect to the ultra-Pa limit was conducted.
The retention rate of inulin was 58.9% to 705%. The commercially available product is Asahi Medical 11 PAN-15#D.
These are various retention rates of HF.

Example 2゜Acrylonitrile 90.7%, methyl acrylate 7.2%
%, acrylic acid 1.2%, methallylsulfonate 0
A copolymer consisting of 9% was dissolved in a 67% nitric acid aqueous solution, and 1
Make a solution with a copolymer concentration of 5% at -5°C,
After FIiA was defoamed, it was used as a spinning stock solution.

This spinning dope was spun under the same conditions as in Example 18. Ml of full water! ! Please remember to set it at 13m/a once.

The obtained hollow fiber had an inner diameter of 205μ and an outer diameter of 305μ.

With a film thickness of 50 μm, the cross-sectional structure has an active layer with a thickness of 0.15 μm and dense pores on the inner and outer surfaces of hollow Ili fibers.

Continuing from the active layer, a graded porous lll1 structure region follows the active layer on the outer surface with lOμ, and the active layer on the inner surface with 5
The ultrafiltration rate and the retention rate of inulin permeation rate obtained by the filtration operation of the hollow mesh obtained in the presence of μ and a support layer are respectively compared with Example 1.0 commercial product.

Commercial product Example 2 Retention rate of ultrafiltration rate 47.0% 87.2% Retention rate of inulin 58.9% 93.5% Procedure Supplement Ministry May 27, 1980 Commissioner of the Patent Office Shimada Yosho 1 Indication of the case Patent application No. 1986-190673 2 Name of the invention Selective semi-permeable membrane 3 Person making the amendment Relationship to the case Patent applicant Asahi Medical Co., Ltd. 4 Agent 2 Toranomon-chome, Minato-ku, Higashi-g. No. 29, Toranomon Sangyo Building, 5th floor, 6 The statement in the statement of contents of the amendment has been amended as follows. il+, page 4, line 18, "0.01 to 10.0% is preferable" has been changed to "0. (21, page 5, line 6, insert ``substantially'' after ``towards'').

(31, page 5, line 4, insert the following statement after “It is an aggregate.”
The pore diameter at the junction with the graded porous layer is the same as the pore diameter of the porous material, and the pore diameter at the junction with the active layer is the same as the pore diameter of the active layer, forming a continuous graded porous structure. ” (41, page 5, line 7, after “preferably,” “more preferably F11-10%
It is. ” is inserted.

(5), page 5, lines 7 to 9, “Amount of fractionation of active layer...
It is preferable to also remove ".

t61. m5jk lines 19-20 ``The thickness of the active layer is preferably about a mountain.

' shall be amended as follows.

“The thickness of the active layer is 0.1 to 10 μm, preferably 0.1 μm to 10 μm.
It is about 1 to 1μ. As mentioned above, it is about 0.1 to 10%, more preferably 0.1 to 5% of the entire film thickness. (7) % "0.5-50%" on page 6, line 4 is corrected to "0.29-50%."

(8), 6th QS line Correct "more than the hole diameter" to "more than the hole diameter".

Procedural amendment Honorary July 26, 1980 Percent Office Commissioner Oro Wakasugi Gen 1 Indication of the case Patent application No. 1986-190673 2 Name selective semi-permeable membrane of the book 3 Person making the amendment Relationship with the case/% Accounting Consultant Asahi Medical Co., Ltd. 4 Agents 5th Floor, Toranomon Industrial Building, 2-29 Toranomon-chome, Minato-ku, Tokyo Detailed explanation of the invention in the specification - I Brief description of the drawings #J Pumaro □￥ il '7. -Drawing 6 The description of the contents of the amendment shall be amended as follows.

(1) Insert the following statement between lines 9 and 10 on page 6.

[Schematically showing the structure of the selective semipermeable membrane of the present invention, the first
K as shown in Fig. 2 and Fig. 2.

It is a partial cross-sectional view when a hollow fiber structure is used as shown in FIG.
Active layer 1 on the outer wall surface, inclined porous structure part 2 on the inside
, further inside there is a porous layer 3. In the case of the example shown in FIG. 1, giant vacuoles 4 are present in the porous layer 5, but these can be eliminated by changing the manufacturing method.

FIG. 2 is an enlarged view of the inclined porous structure portion 2 of FIG. (21, page 12, line 7, add the following text in its entirety.

``Figure 1 is a partial cross-sectional schematic diagram showing the membrane structure of the present invention;
The figure is an enlarged view of the inclined porous structure portion of FIG. 1. (3) Submit the drawings (Figures 1 and 2) as shown in the attached sheet.

Agent Takeshi Kiyomizu:! ``lj high also kitt+B

Claims (1)

[Claims] 1) A membrane having a dense active layer on at least one of its surfaces, a porous layer inside the active layer, and a boundary between the active layer and the porous layer having a graded porous structure. A selective semipermeable membrane consisting of a certain polymer membrane. 2) The selective semipermeable membrane according to claim 1, which is made of an acrylonitrile-based enriched material. 3) An acrylonitrile containing 80 wt% or more and 20 wt% or less of several vinyl-based phosphor groups having any of the functional groups carmexyl, methyl ester group, ethyl ester group, amide group, and sulfonic acid group. A selective semipermeable membrane according to the patent-required scope Is1, characterized in that it is made of a cliff nitrile-based composite. 4) Acrylonitrile compound is at least 85w1%
The above acrylonitrile, 1.0 to 10 wt% carboxyl group-containing vinyl monomer, 50 to 10 wt% methyl ester group containing vinyl monomer, 0.1 to 1. The selective semipermeable membrane according to claim 2, which is a compound consisting of four components of vinyl phosphor containing 0% sulfonic acid groups. 5) Claim 1, t, 2@, or 3, characterized in that the semipermeable membrane has a hollow fiber shape, or r
! #i Selective semipermeable membrane according to item 4.