JPS63274433A - Preparation of oxygen enriching multilayer composite hollow yarn membrane - Google Patents

Abstract

PURPOSE:To improve durability and to increase a permeation speed, by forming a multilayer composite hollow yarn membrane by alternately laminating a separation membrane layer having a thickness of 1mum or less composed of an oxygen permeable polymer and a porous membrane layer composed of a crystalline polymer. CONSTITUTION:A polymer (polymer a') having oxygen separation factor of 3 or more and a crystalline polymer (polymer b') having a m.p. of 170-250 deg.C are alternately arranged and the polymer b' is arranged on inner and outer surface sides and the polymers a', b' are subjected to melt composite spinning using a multiple cylindrical nozzle. Subsequently, the composite spun yarn is stretched to make the part of the polymer b' of the polymer a' porous to obtain an oxygen enriching multilayer composite hollow yarn membrane wherein a separation membrane layer A' with a thickness of 1mum or less composed of the polymer a' and porous membrane layer B' composed of the polymer b' are alternately laminated and said layers B' are arranged on the inner and outer surface sides. As the polymer a', poly-4-methylpentene-1 having thermal deformation temp. of 75-85 deg.C is pref.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a separation membrane that improves combustion efficiency and has an oxygen enrichment ability that can be used for oxygen therapy and the like.

[Prior art]

The method of separating specific gases from gas mixtures using membranes is already well known, but when obtaining oxygen-enriched air from air, it is also possible to obtain a large amount of gas permeation with a small device. This is a major technical challenge. Normally, the permeation rates QOz and QNz of oxygen and nitrogen passing through a homogeneous membrane, and the separation coefficient (α) are expressed by the following equations.

QOz2PO2/L, QNz = PN2/L
α=PO goose/PN2= QN! / QOzQ: Gas permeation rate (cm' - cm-"・5ec-' sc
tnHg-']P: Gas permeability coefficient [crl-cm
・cm-"・5ea-' ・m1g-5] α: Separation coefficient L: Film thickness 9, PO,, PN, , α is a factor determined by the membrane material. 65, for materials with large PO and α Development and technology to reduce the membrane thickness of the material are important.Furthermore, the form of the membrane is also important in practical terms, and hollow fiber membranes with a large membrane area per unit body are more advantageous than flat membranes. As one direction of thin film technology, a method is known in which a thin film is formed on a porous substrate by a coating method, a plasma polymerization method, a vapor deposition method, or the like.

[Problems to be solved by the invention] However, with methods such as coating methods and vapor deposition methods,
Since the thin film component that provides the separation function is coated on the porous substrate, there is a problem that the thin film component invades the pores of the substrate, making it impossible to obtain a substantially thin film. In addition, to avoid this phenomenon, there is a method in which the pores of a porous substrate are filled with a soluble substance in advance, and the soluble substance within the porous substrate is eluted after a thin film is completely formed on the surface. Uniform 'II
There is a problem that the I film layer is difficult to obtain and is easily damaged. Furthermore, there are other problems such as formation of peer holes, non-uniform film thickness, poor durability, and insufficient contact with the substrate.
The non-invention was made to solve the above problem, which is difficult to put into practical use.
The present invention provides a method for producing a multilayer composite hollow fiber membrane having a thin layer having a separation function, excellent durability, high permeation rate, and oxygen enrichment ability.

[Ninth Means for Solving the Problems] The gist of the present invention is to obtain an oxygen permeability coefficient of 8 x 10-10aIr''cmacfR-
Polymers of "5oC-t・6RHg-" or more (hereinafter referred to as "1
A crystalline polymer having a melting point of 170 to 250°C (hereinafter referred to as "polymer b") is arranged and placed alternately, and the polymers are arranged on the inner surface side and the outer surface side and melted. A separation membrane layer having a thickness of 1 μm or less consisting of polymer a, which is characterized by composite spinning, and then stretching to make the entire part of the polymer a thinner layer, and making the part of the polymer porous. and porous membrane layers B made of a polymer are alternately laminated, and B is arranged on the inner surface and the outer surface. Using a spinning nozzle, a polymer with an oxygen separation coefficient of 3 or more (hereinafter referred to as ``polymer,''), a crystalline polymer with a melting point of 170 to 250 ° C. (hereinafter referred to as ``polymer b/J''), and gold were arranged alternately. , and polymer b
' is arranged on the inner surface side and on the outer surface side and subjected to melt composite spinning, and then the part of the polymer a' is made into a thin layer by stretching, and the part of the polymer d is made porous. Polymer a
Separation membrane layer A′ with a thickness of 1 μm or less consisting of ′ and polymer b′
The present invention provides a method for producing an oxygen-enriched multilayer composite hollow fiber membrane in which porous membrane layers B' consisting of the following are alternately laminated, and crosspieces are disposed on the inner and outer surfaces.

The oxygen permeability coefficient conveniently used in the uninvented method is 8X1
0-″” (cm” * cm ・cps-” ・θe
Examples of the polymer a having an oxygen enrichment function of c-"・an Hg-') include silicone rubber, silicone-based polymers such as copolymers of silicone and polycarbonate, poly-4
- Polyolefin polymers such as methylpentene-1, per-70 alkyl fluorine-containing polymers, cellulose polymers such as ethyl cellulose, polyphenylene oxide, poly-4-vinylpyridine, and copolymers or blends of these polymer materials. I can name things. Among these, a copolymer of silicone and polycarbonate can be cited as a particularly preferable polymer in consideration of ease of molding, mechanical strength, and oxygen permeability coefficient. Incidentally, those having a large oxygen permeability coefficient are suitable for improving combustion efficiency in boilers and the like.

Also, 11! Examples of the oxygen-enriching functional polymer a' having an elementary separation coefficient of 3 or more include silicone polymers, polyolefin polymers such as poly-4-methylpentene-1, linear low density polyethylene, and bar 70 alkyl fluorine polymers. Containing polymers, cellulose polymers such as ethyl cellulose, polyphenylene oxide, poly-4-vinylpyridine, and copolymers or blends of these polymer materials can be mentioned. Among these, ease of molding,
Considering all factors such as oxygen permselectivity, particularly preferred polymers have a heat distortion temperature (MuSTM D648) of 75 to 8.
5° C. and does not become porous during stretching, poly-4-methylpente 7-1 can be mentioned.

Note that membranes with a large oxygen separation coefficient are suitable for oxygen enrichment membranes for medical use.

Crystalline polymer b (or b/
), any polymer can be used as long as it can be made porous by stretching, but polyethylene,
Polypropylene, polyolefin thread such as poly-4-methylpentene-1, and polyvinylidene fluoride, Tetra 70
It is preferable to use a crystalline polymer such as ethylene.

In addition, when a copolymer of silicone and polycarbonate is used as polymer a (or &/ ), the melting point is 170 to 2.
Poly-4-methylpentene-1 and polyvinylidene fluoride between 50°C are suitable.

In the present invention, a multilayer composite hollow fiber membrane is manufactured using a multi-cylindrical spinning nozzle, but normally a hollow fiber manufacturing method having concentrically arranged discharge ports capable of forming a layer structure of three or more layers is used. nozzle is used.

The outermost layer and the innermost layer of the nozzle contain 1 polymer b (or polymer b
'> @supplied, and in the middle layer, when the structure is three-layered, polymer a (or 1 polymer a/ ) is supplied, and when the structure is more than that, polymer b (or polymer b/ ) is further supplied, and the multi-layer structure is To obtain undrawn hollow fibers, the spinning conditions are not particularly limited, and the optimum conditions can be set depending on the type of polymer constituting each layer.
(or polymer b') as poly-4-methylpentene-
1, the spinning temperature is about 220 to 300°C,
The spinning draft is about 100 to 3000, and the quench temperature during spinning is about room temperature.

The spun undrawn hollow fibers are then stretched to make them porous, and the known method used for polyolefins is used to make them porous by stretching.

That is, by a small amount of stretching at around room temperature, micropores are generated in 1- of polymer b (or polymer b') and whitened.
Subsequently, the pores can be enlarged and the pore shape stabilized by preheated stretching. During this time, polymer a (or polymer, r
) is not made porous, and therefore becomes thinner in proportion to the increase in stretching ratio. At that time, polymer a (or polymer a'
It is necessary to appropriately control the stretching conditions so that the film thickness of the separation membrane layer (or AI) consisting of ) is 1 μm or less.

The stretching conditions are also not particularly limited, and the optimal conditions can be set depending on the type of polymer, but for example, for polymer b (or polymer b
') When poly-4-methylpentene-1 is used, the cold stretching conditions are 1.2 to 165 times at room temperature, the hot stretching conditions are about 100 to 125°C, and the total stretching ratio is zO to A condition of approximately 50 times the amount is adopted.

The multilayer composite hollow fiber membrane obtained by the inventive method has at least a three-layer structure. If it has a three-layer structure,
The outer surface and the inner surface are porous membrane layer B (or B'),
The intermediate layer is a separation layer A (or A') having a separation function. The porous membrane layer B (or B') has the role of reinforcing the membrane layer A (or AI) and protecting it from damage. Basically, one layer of the separation membrane layer A (or A') is sufficient, or a multilayer structure of two or more layers may be used depending on the purpose. Also, the thickness of the separation membrane layer (or A') is 1μ.
If it exceeds 1 μm, it is not preferable because the oxygen permeation rate cannot be improved.

〔Example〕

Examples will be explained below.

Example 1 A hollow fiber manufacturing nozzle was used that could form a three-layer structure, and the inner and outer layers were coated with poly-4-methylpentene-1 ( Copolymer of silicon and polycarbonate (G, B, Cope manufactured by Mitsui Petrochemical Co., Ltd.) in the middle layer part
d I4R, 3320) l, discharge temperature 250°C, discharge linear velocity 3 cm/win-winding speed 30 m/mi
The resulting undrawn hollow fibers had an inner diameter of 250 μm.
The layers each having a thickness of 30% α2.30 μm were arranged concentrically from the inside.

The unstretched hollow fibers were annealed at 160° C. for 1 hour. Furthermore, the annealed yarn was stretched for 40 minutes at room temperature, and then
Hot stretching was carried out in a heating furnace at 120° C. in Step 1 to give a total stretching amount of 250 inches, and further heat celatra was carried out in a heating furnace at 140° C. to obtain a multilayer composite hollow fiber membrane.

This multilayer composite hollow fiber membrane has an inner diameter of 200 μm, and layers 25 and α1.25 μm thick tW from the inside are arranged in concentric circles, and as a result of observation with an electron microscope, holes are formed on the inner and outer surfaces. Slit-shaped holes each having a width of 8 μm were formed. In addition, when the oxygen enrichment ability was measured, the oxygen permeation rate was 7.8 x 10-'(cm" (ST
P)/crn”・sec -cmHg J% II
Element passing rate 19 x 10-' [3” (8TP)/
c*”-sac-mHg], and the oxygen selectivity was 20.

Example 2 Using the same hollow fiber manufacturing nozzle as in Example 1, polyvinylidene fluoride (KF-100 manufactured by Kureha Chemical Co., Ltd.) was used for the inner and outer layers.
0), a copolymer of silicon and polycarbonate (G, ffi, 0opel L manufactured by Co., Ltd.) for the intermediate layer.

R, 5520), the discharge temperature was 245°C, the discharge linear velocity was 3 cM/min, and the winding speed was 30 m/min.
It was spun with The obtained undrawn hollow fiber had an inner diameter of 230 μm, and layers having thicknesses of 28 μm and α3.28 μm were arranged concentrically from the inside.

The unstretched hollow fibers were annealed at t-140° C. for 1 hour. Further, the annealed system was stretched by 40 degrees at room temperature, then hot stretched in a heating furnace at 120°C until the total amount of stretching reached 250 degrees, and further heat set in a heating furnace at 140°C to form a multilayer composite hollow. A thread membrane was obtained.

This multilayer composite hollow fiber membrane has an inner diameter of 190 μm and a
5. Layers with a thickness of α2.25 μm are arranged concentrically, and as a result of observation with an electron microscope, slit-shaped pores with a width of 0.06 μm are formed on the inner and outer surfaces. Ta. Also, the oxygen permeation rate is l 5 × 10
-' [cIn”(STP) 7cm” * sea
-cmHg], nitrogen permeability is 1.3X10-' (c
m'' (STP) 761 M''·sec-mHg), and the oxygen selectivity was 2.0.

Example 3 Using the same hollow fiber manufacturing nozzle as in Example 1, poly4-methylbe/ten-1 (Mitsui Petrochemical Co., Ltd. gTPX MXO07 heat distortion temperature 90°C) was used as the polymer material for the inner and outer layers.
, poly-4-methylpentene-1 is used as the polymer material of the middle layer.
(Mitsui Petrochemical Co., Ltd. 1TPX MXOOI heat distortion temperature 8
0°C), discharge temperature 250°C, and discharge linear velocity 5 cm.
/min, and the winding speed was 50 m/min. The obtained undrawn hollow fiber had an inner diameter of 250 μm, and layers each having a thickness of 30 and α of 2.30 μm and having a thickness of kW were arranged concentrically from the inside.

The undrawn hollow fibers were annealed at 1160° C. for 1 hour. Further, the annealed yarn was stretched by 40 inches at room temperature, and then hot-waxed in a heating furnace @ 120°C until the total amount of stretching reached 250 cm. A composite hollow fiber membrane was obtained.

This multilayer composite hollow fiber membrane has an inner diameter of 200 μm, and layers having a thickness of 25 μm and α1.25 μm from the inside are arranged concentrically, and as a result of observation with an electron microscope, there are holes on the inner and outer surfaces. Slit-shaped holes each having a width of α08 μm were formed, and the oxygen permeation rate was 7. OX10
″″’(3”(8TP)7m”・sec-ctRHgJ
, the nitrogen permeation rate is 1,6 x 10-'(cm")
8, T P, )/z”・sea・onHg 3, the oxygen selectivity was 4.1.In addition, air was flowed through this membrane and the oxygen concentration in the permeated gas was measured. was 40 cm, and the membrane was sufficiently usable for medical purposes.

Example 4 Using the same hollow fiber manufacturing nozzle as in Example 1, polyvinylidene fluoride (Kureha Kagaku Co., Ltd. IP-100) was used for the inner and outer layers.
0), poly4-methylbenfy-1C Mitsui Petrochemicals TPX MXOOl) was used for the intermediate layer, and the discharge temperature was 24
5°C, discharge linear velocity BaI &/min, winding speed S O
The yarn was spun at an/min. The obtained undrawn yarn has an inner diameter of 230 μm, and 2B and α3.28 μm from the inside.
The unstretched hollow fibers were annealed at 1140° C. for 1 hour. Further, the annealed yarn was stretched by 40 degrees at room temperature, then hot-stretched in a heating furnace at 120° C. at a rate of 250 degrees, and then heated at 140° C. in a heating furnace (heat cera). A hollow fiber membrane was obtained.

This multilayer composite hollow fiber membrane has an inner diameter of 190 μm and a
5. Layers with a thickness of α2.25 μm are arranged concentrically, and as a result of observation with an electron microscope, slit-shaped pores with a width of α06 μm are formed on the inner and outer surfaces, respectively. Ta. In addition, the oxygen permeation rate is 2.8X10"[sub" (STP) /yR" ・sea * cmHg
], nitrogen permeability is 07×10−' [cfR” (
8TF) 151” ・sec ・anHgJ,
Oxygen selectivity was 40. ′! In addition, when air was flowed through this membrane and the oxygen dI degree in the permeated gas was measured, the oxygen concentration was 40%.

〔Effect of the invention〕

The method of the present invention provides V oxygen enrichment function 1 by melt spinning drawing method.
To! It has the following excellent effects: it is possible to easily thin the thin film layer, suppress damage to the thin film layer, and form a hollow fiber-like laminated structure in which adhesion between the eyebrows is not a problem. However, according to the uninvented method, there is no pinhole in the intermediate layer, the oxygen permeation rate is on the order of 104 to 10-5, and the oxygen selectivity is on the order of 2.0-40 or higher. A multilayer composite hollow fiber membrane can be obtained.

This membrane can be applied to oxygen enrichment to improve combustion efficiency in boilers and the like, and to medical fields that require oxygen therapy for chronic respiratory failure and other conditions.

Procedural amendment filed August 28, 1988, Japanese Patent Application No. 110158/1982 2, Name of the invention: Process for manufacturing oxygen-enriched multilayer composite hollow fiber membrane 3, Relationship with the person making the amendment case Patent applicant: Kyobashi, Chuo-ku, Tokyo 2-3-19 (603) Mitsubishi Rayon Co., Ltd. President Akio Kawasaki 4, Agent 2-3-19 Kyobashi, Chuo-ku, Tokyo Sponsored by 6 Column for detailed description of the invention in the specification subject to amendment (1) r7,8XIOJ on page 12, line 13 of the specification
is corrected to r4,0XIOJ.

(2) r3,9X10J on page 12, line 14 of the specification
is corrected as r2,0XIOJ.

(3) [3,5X10J on page 13, line 18 of the specification]
Correct it to 2.6X10J.

Claims (5)

[Claims] (1) Using multiple cylindrical spinning nozzles, the oxygen permeability coefficient is 8.
×10^-^1^0cm^3・cm・cm^-^2・s
ec^-^1・cmHg^-^1 or more polymer (hereinafter referred to as "
Polymer a") and a crystalline polymer with a melting point of 170 to 250°C (hereinafter referred to as "polymer b") are arranged alternately, and polymer b is arranged on the inner surface side and the outer surface side and melted. Composite spinning and then stretching to make the polymer a thin layer,
A separation membrane layer A having a thickness of 1 μm or less and consisting of polymer a and polymer b, characterized in that a portion of the polymer b is made porous.
A method for producing an oxygen-enriched multilayer composite hollow fiber membrane, in which porous membrane layers B and B are alternately laminated, and B is arranged on the inner and outer surfaces. (2) The method according to claim 1, wherein the polymer is poly-4-methylpentene-1 or polyvinylidene fluoride. (3) Using multiple cylindrical spinning nozzles, the oxygen separation coefficient is 3.
The above polymer (hereinafter referred to as "polymer a'") and a melting point of 17
Crystalline polymers at 0 to 250°C (hereinafter referred to as "polymer b'") are arranged alternately, and polymer b' is arranged on the inner surface side and the outer surface side for melt composite spinning, and then stretched. A porous membrane comprising a separation membrane layer A' having a thickness of 1 μm or less comprising polymer a' and polymer b', characterized in that a portion of the polymer b' of the polymer a' is made porous by A method for producing an oxygen-enriched multilayer composite hollow fiber membrane in which layers B' and B' are alternately laminated and B' is arranged on the inner and outer surfaces. (4) Polymer a' has a heat distortion temperature (ASTM D648)
The method according to claim 3, characterized in that the poly-4-methylpentene-1 is 75-85°C. (5) The method according to claim 3, wherein the polymer b' is poly-4-methylpentene-1 or polyvinylidene fluoride.