JPH05508106A - Porous polybenzoxazole and polybenzothiazole membranes - 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] 12. The membrane has an average bubble size of 0.05 to 2 μm in the identification layer. The invention according to any one of claims 1 to 3 or 5 to 10, which is a filtration membrane.

13. Polybenzoxazole or polybenzothiazole polymer or copolymer Claims 1 to 3, wherein the layer of the membrane comprising the remer has an average cell size of at least 2 μm. The invention according to any one of Items 3 and 5 to 10.

14. Claim 1.2, wherein the pressure across the membrane is at least about 70 g/cm". Or the invention according to any one of 4 to 13.

15, (1) Solvent acids, PBO or PBT polymers, and solvent acids and Forms a homogeneous solution containing pore-forming compounds that are soluble in organic acids but insoluble in water thing, (2) PBO or PBT polymer and pore-forming compound co-precipitate and PBO or a film containing separate zones of PBT and separate zones of pore-forming compounds. process (11 homogeneous solutions are diluted with aqueous and (3) dissolving the pore-forming compound from the film or membrane. The film or membrane of step (2) is contacted with an organic solvent to give it a porous structure. to let A method for producing a porous membrane, comprising the steps of:

Specification The present invention relates to the field of porous membranes and substrates.

Porous separation membranes are solid polymers with defined pores through which liquids and small solids pass. - Contains matrices. These pores are interconnected, and movement occurs within the pores. . Porous membranes separate mixtures containing two or more components by sieving. of stomata The size depends on the purpose of the membrane. "Ultrafiltration" membranes are typically 20-500 ohms It has an average pore size of "Microfiltration" membrane is 0.05-5 It has an average pore size of μm. This provision is for convenience rather than strict. However, membranes with other pore sizes are also effective. Membrane chopsticks with larger pores Often used as a base layer in composite membranes, it is used as a thin, dense or porous base material for footwear. but does not substantially contribute to separation. Similarly, one asymmetric membrane A large substrate supporting one or more discriminating layers of dense or porous polymer with pores. Contains a layer with pores.

The separation performance of porous membranes is typically determined by flux and retention. on). Flux is the flow that permeates through a given area of the membrane. is a measure of the speed of Flux is typically in units of ml at STP permeating through the membrane (measured in surface m of the membrane (time) (pressure across the membrane cmHg).Other units is gallons/ft2-day. Retention is measured by the membrane It is a measure of the proportion of molecules of a particular size that are allowed to pass through. Exclusion is often molecular weight expressed as a cutoff.

The synthesis and use of porous membranes is covered in many publications, e.g. 15 Kirk-Othmer E. ncy, Chem Tech, Me+nbrane Technology y, 92 (J, Wiley &5ons1981); 23 Kirk -Othmer Eney, Chem Tech, Ultrafiltrat ion, 439 (J, Wiley & 5ons 1981); Strat man,”5ynthetic Membranes andTheir Pr eparation", 5ynthetic Membranes: 5ci ence Engineering and Application 1-37 (D, Re1del publ, 1986): and Kestin g.

5ynthetic Polymeric Membranes (2nd E d,) 1-21.153-185 and234-285 (J, Wiley & 5on) (1985).

Certain properties are desirable for effective use of membranes with good flux and retention properties. The membrane is a place It should be strong enough to withstand the pressure required to permeate the membrane at the desired flow rate. Ru. The membrane should be insoluble in all components of the mixture to be separated . If high service temperatures are desired, the membrane must retain its integrity for a reasonable period of time at that temperature. Must be. Good flux, good retention and/or molecular weight cutoff, good strength A novel porous material that offers one or more of the following advantages: high temperature, good solvent resistance, and good high temperature stability. membrane is required.

One aspect of the present invention is (11 high pressure zones (2) Low pressure zone The porous The membrane is made of polybenzoxazole polymer or copolymer or polybenzothiazo containing polymers or copolymers. is a method for separating mixtures containing one separable component, in which the liquid passes through a membrane. suitable for eliminating at least a portion of the separable components at a pressure sufficient to contacting the mixture with one side of a porous membrane having pores of The porous membrane is made of polybenzoxazole polymer or copolymer or polybenzothiazole polymer or copolymer. It is characterized by containing an azole polymer or copolymer.

A third aspect of the present invention is a porous hollow fiber membrane, the membrane comprising polybenzoxazole polybenzothiazole polymer or copolymer or polybenzothiazole polymer or copolymer It is characterized by containing a polymer.

A fourth aspect of the present invention is a polybenzoxazole polymer or a polybenzothiazole polymer. A membrane containing polymer or copolymer, one or two of which is 500 microns thick. It has an open cell structure with an average cell diameter of 1 to 200 microns. It is characterized by

The fifth aspect of the present invention is the following steps (1) Soluble in solvent acids, PBO or PBT polymers, and solvent acids and organic acids forming a homogeneous solution containing a pore-forming compound that is insoluble in water; (2) PBO or PBT polymer and pore-forming compound co-precipitate, and PBO also or a pore-forming compound containing separate zones of PBT and separate zones of pore-forming compounds. The homogeneous solution of step (1) is diluted with an aqueous solution under conditions that form a lume or film. and (3) dissolving the pore-forming compound from the film or membrane. The film or membrane of step (2) is brought into contact with an organic solvent to give it a porous structure. to touch A method for producing a porous membrane comprising:

PBO and PBT polymers and copolymers are often resistant to most organic solvents. very high solvent resistance, high tensile strength and elasticity or different differentiation within composite membranes. It may be used as a base layer for layers. The membrane also has at least two layers, the It may be an asymmetric membrane, at least one of which is porous.

definition The following terms are used repeatedly in this specification, unless otherwise indicated. has the meaning and preferred embodiments defined in .

AA-BB-polybenzazole (AA/B B-P BZ) - first aroma a monomer unit having a group group (Ar'), a monomer unit having a group group (Ar'), a - and a second azole ring, and is bonded to the 2-carbon of the second azole ring by a single bond. A polybenzazole polymer characterized by a divalent organic moiety (DM). divalent organic part DM is inert under conditions suitable for the synthesis of PBZ polymers; Preferably it is the second aromatic group (Ar”).The monomer unit is preferably the second aromatic group (Ar”). The first azole ring in the adjacent monomer unit by bonding from the valent organic group (DM) is bonded to the 2-carbon of Monomer unit suitable for AA/BB-PBZ polymer Preferably, the following formula 1 (in the above formula, Z is the same as defined for the azole ring) and all others have the meaning given above) It is expressed as

AB-polybenzazole (AB-PBZ) - monomer with a first aromatic group unit and one azole ring fused to said first aromatic group. benzazole polymer. This unit is an azole within one monomer unit. Bonded to the aromatic group of the adjacent monomer unit by a bond from the 2-carbon of the ring . Monomer units suitable for AB-PBZ polymers preferably have the following formula 2 (in the above formula , Z are as defined for the azole ring, and all others have the above meanings. ) It is expressed as

0-amino basic moiety-bonded to an aromatic group, preferably essentially (1) Some amine groups bonded to aromatic groups and (2) Hydroxy, thiol or -grade or secondary amine groups attached to aromatic groups in the t-position The part consisting of 〇-amino basicity in monomers useful in producing the polymers of the present invention moieties include hydroxy or thiol moieties, most preferably hydroxy moieties including.

Aromatic group (Ar) - any aromatic ring or ring system. Aromatic groups include this aromatic group Size does not matter as long as it is not so large that it interferes with the synthesis, processing, or use of the polymer. There isn't. Each aromatic group independently preferably has up to about 18, more preferably about 12 The following most preferably contain no more than about 6 carbon atoms. each is a nitrogen-containing heterocycle However, it is preferably a carbocyclic ring, and more preferably a hydrocarbyl ring.

Unless otherwise indicated, each aromatic group represents one aromatic ring, a fused ring system, or a single aromatic group under the polymerization conditions. attached by a divalent moiety or by a bond that is inert with respect to the PBZ polymerization reagent in unfused ring systems containing two or more aromatic rings. Suitable divalent moieties include, for example, cal Bonyl group, sulfonyl group, oxygen atom, sulfur atom, alkyl group and/or perfluor Contains olorated alkyl groups. Each aromatic group is preferably one 6-membered ring.

Each aromatic group is stable in solvent acids and polybenzazole polymers or Substituents may be included that do not interfere with the synthesis, processing and/or use of the copolymer.

Examples of preferred substituents include halogen, alkoxy moieties, aryloxy moieties or aryloxy moieties. Contains alkyl group. More preferred substituents are alkyl having up to about 6 carbon atoms. group or halogen. Most preferably, each aromatic group has the substituents required below. Contains only.

Azole ring - oxazole, thiazole or imidazole ring. nitrogen atoms and oxygen, The carbon atom bonded to both sulfur or secondary nitrogen atom is 2-carbon as shown in formula 3 below. It is basic.

(In the above formula, Z is 10-2-8-1 or -NR-, and R is hydrogen, aromatic, or Aliphatic groups are preferably hydrogen or alkyl groups, most preferably hydrogen. ) In the polymers of the invention, each azole ring is independently oxazole or thiazole. and preferably oxazole. In the PBZ polymer, each azole The 4- and 5-carbons of the ring are usually fused with aromatic groups.

Electron-deficient carbon groups (Q) - e.g. column 24 of U.S. Pat. No. 4,533,693. Reacts with 0-amino basic moieties in solvent acids, such as the groups shown in lines 59-66. Any group containing a carbon atom that forms an azole ring.

Preferred electron-deficient carbon groups are carboxylic acids, acid halides, metal carboxylates. salt, diano group and trihalomethyl group. Halogen in electron-deficient carbon group (J-like) Preferably it is chlorine, bromine or iodine, more preferably chlorine.

Polybenzazole (PBZ) Polymer-1-Polybenzoxazole and Polybenzoxazole Benzobisoxazole (PBO), Bolibe: Nozothiazole and Polybenzo Bisthiazole (PBT) and polybenzimidazole or polybenzobisimide Polymers from the group of Dazoles (FBI). “Polybenzoxazole (PBO) J means that each monomer unit is an aromatic group (this does not have to be a benzene ring) ) refers to a polymer containing an oxazole ring bonded to Also [polybenzoyl] Sasol (PBO) J is poly(phenylene-benzo-bis-oxazole) and Other polysaccharides in which each monomer unit contains many oxazole rings fused to an aromatic group means mer. The same interpretation applies to polybenzothiazole (PBT) and polybenzoi. Also applies to Midazole (FBI). Polybenzazo used in the membrane of the present invention The polymers are PBO and/or PBT polymers and/or copolymers.

Solvent acids - sulfuric acid, methanesulfonic acid, trifluoromethylsulfonic acid, polyphosphoric acid and non-oxidizing liquid acids capable of dissolving PBZ polymers, such as mixtures thereof. child The material must not substantially oxidize dissolved AB- and BB-PBZ monomers. Must be. The solvent acid is preferably polyphosphoric acid or methanesulfonic acid and phosphoric pentoxide. A dehydrating acid such as a mixture of Preferred concentration of P2O in methanesulfonic acid degrees are described in U.S. Pat. Ru. The concentration of P2O5 in polyphosphoric acid is determined by U.S. Pat. No. 4.533.693 and 4. No. 722.678. At the start of the reaction preferably at least about 80 weight percent, more preferably at least about 85 weight percent, most preferably preferably 87 percent by weight P2O, preferably about 90 percent More preferably, it has a P2O5 content of no more than about 88 percent.

AA - Monomer is a divalent organic moiety that does not interfere with the synthesis, processing or use of the polymer. It contains two electron-deficient carbon groups bonded by . Electron-deficient carbon group has the above meaning. do. The divalent organic moiety preferably includes a saturated aliphatic moiety or an aromatic group, and more preferably Preferably containing aromatic groups, most preferably electron deficient carbon groups in the para position with respect to each other. Contains an aromatic moiety with . Examples of suitable AA-monomers are U.S. Pat. No. 4,533. ．． No. 693, columns 25-32, Tables 4-6. AA-monomer Preferred examples are terephthalic acid, isophthalic acid, bis-(4-benzoic acid) and oxy- Contains C-bis-(4-benzoic acid) and their acid halides. AA-Mono Other examples of mer are bis-(4-benzoic acid) sulfone, bis-(4-benzoic acid) sulfone, ton, bis-(4-benzoic acid) isopropane, 1.1.1.3.3.3-hexane Fluoro-2,2-bis(4-benzoic acid)propane, 1,4-bis(oxy) -4-benzoic acid) including perfluorocyclobutane and their acid halides . The AA-monomer preferably has the following formula 4 %formula% (In the above formula, DM is a divalent organic moiety and nucleus Q is an electron-deficient carbon group) It is expressed as

BB-monomer is 1. Aromatic group 2. 100-amino basic moiety 3 bonded to the aromatic group; a second 0-amino basic moiety. Aromatic groups and 0-amino basic moieties has the meaning given above.

The BB-monomer preferably has the following formula 5 (In the above formula, Ar' is the above-mentioned aromatic moiety, and each Z is the same as shown in the azole ring. (with regulations). Aromatic groups are tetravalent naphthyl, biphenyl, diphenyl Containing multiple fused and unfused rings such as ether or diphenyl sulfone preferably a 6-membered ring such as a tetravalent phenylene or pyridinylene ring. Ru. Suitable examples of BB-monomers are described in U.S. Pat. No. 4,533,693, column 1. 9-24, Tables 1 to 3. Examples of preferred BB-monomers are 4. 6-Diamylsorcinol, 2,5-diaminohydroquinone, 1,4-dithio- 2,5-diaminobenzene, bis-(3-amino-4-hydroxyphenyl)ethyl ether, bis-(3-amino-4-hydroxyphenyl)sulfone, bis-(3 -amino-4-hydroxyphenyl)ketone, bis-(3-amino-4-hydro xyphenyl)isopropane, 1,1.1.3.3.3-hexafluoro-2, 2-bis-(3-amino-4-hydroxyphenyl)propane or 3,3'-di Contains amino-4,4'-dihydroxybiphenyl. BB-monomer is typically is stored as a salt of a non-oxidizing acid such as hydrogen chloride or phosphoric acid.

The AB-monomer is preferably 1. aromatic group 2. the first 0-amino basic moiety 3 bonded to the aromatic group; Contains combined electron-deficient carbon groups. The male-deficient carbon group is directly attached to the aromatic group within the monomer. If the aliphatic compound is is attached to an aromatic moiety by a moiety such as an aromatic moiety. AB-monomer - is preferably the following formula 6(a), more preferably the following formula 6(b) (In the above formula, RB is an aliphatic or aromatic group that is inert in the binding or polymerization conditions. parts, the others have the meanings given above). Examples of suitable ΔB-monomers are shown in U.S. Pat. No. 4,533,693, columns 32-35, Tables 7-8. ing. Preferred examples are 3-amino-4-hydroxy benzoic acid, 3-hydroxy -4-aminobenzoic acid, 371cabuto-4-aminobenzoic acid, and these acids Contains halides or esters.

The sources and synthesis of AA-1BB- and AB-monomers are described in U.S. Pat. 766, No. 244 (August 23, 1988), Lysenko's 835, 30 No. 6 (May 30, 1989), and 1nbasekaran's Prepara t1on4, No. 806.688 (February 21, 1989).

As used herein in the description of AB- and BB-monomers, monomers The amine group and the two moieties are shown as attached to the aromatic group without indicating their position. , it is the following formula 7(a)-(b) and 1IEncy, Po1y, Sc As shown in 602 of i, & Eng, (1) each amine group has two parts and (2) the monomer contains two 0-amino basic moieties. If it has, one primary amine group and 2 moieties are symmetrical with respect to other amine groups and 2 moieties. in the trance or trance position It should be understood that

The same interpretation is 11 Ency, Po1y, Sci, & Eng, 60 2, the nitrogen atom of the azole ring fused to the aromatic moiety and the Also applies to minutes.

Polymers useful in the practice of the invention The membrane of the present invention comprises polybenzoxazole (PBO) and/or polybenzothiazo polybenzazole (PBT) polymer or copolymer (hereinafter collectively referred to as polybenzazole) polybenzazole (PBZ) polymer selected from the group consisting of -Including. This polybenzazole polymer is essentially AA/B B-P B Consists of Z monomer unit and/or AB-PBZ monomer unit. or , polybenzazole polymers are more complex copolymers, which are AA/B to B-PBZ monomer unit 1 and/or AB-PBZ monomer unit and Monomers of other polymers such as poly(aromatic ethers) or polyamides Including knits.

essentially AA/BB-PBZ monomer units and/or AB-PBZ monomers Polybenzazole polymers consisting of units are known. polybenzazole poly Ma is typically divided into many ranges.

The polymer preferably consists essentially of AA/BB-PBZ monomer units. Ru. Each monomer unit independently preferably each Z is an oxygen atom or a sulfur atom. is expressed by one of formulas 1 and 2.

Polybenzazole polymers also include 11 Ency, Poly, Sci, 　&εng.

605-607 of the Rigid Rod AA/BB-Polymer, Semi-rigid rod mesogenic polymer or soft coil (non-mesogenic) Gen) It is classified as a polymer.

Rigid rod AA/BB - polymer is essentially straight, i.e. less than 150° does not include the chain angle. Typically the first aromatic group is 1.2.4. 5-phenylene moiety, 2.3.5.6-biphenylene moiety, 2,3.5.6-pi Rimidinylene moiety or 2.3.6.7-naphthalene moiety or substituted products thereof It is. The 1.2.4.5-phenylene moiety is preferred. J[[Specifically, divalent organic The moiety is a 1,4-phenylene moiety or a 4,4'-biphenylene moiety. 1,4 -Di-functional nylene moieties are preferred. Rigid rod polybenzazole polymers are preferred or essentially the following formulas 8(a)-(d), more preferably 8(a) or (b) It consists of a monomer unit represented by one of the following.

The semi-rigid rod AB-PBZ polymer preferably has essentially the formula 9(a)-(d) more preferably one or more monomer units represented by formula 9(a) or consists of its permutants.

nd Soft coil polybenzazole polymers are AB- or AA/BB monomer units. If the monomer unit is not linear in nature (i.e. (i.e., having a chain angle of less than 150°). Literature, K, U, Buhl, er's 5 pezialplaste 838-866 (Akadem ie-Verlag 1978) in Table 158 from 844-854. The structure and synthesis of many soft coil polybenzazole polymers have been reported (7).

A preferred soft coil polybenzazole polymer is represented by formula 10(a) below. Contains linked AA/BB-monomer units.

(In the above formula, each Ar'' is an aromatic group, and X is a bond or a polymer under PBZ polymerization conditions. a first divalent bonding moiety (X) that is inert to the coupling reagent and the PBZ monomer; , L is Ar''' or Ar-X-Ar, and each Z is independently an oxygen or sulfur atom. ) Ar″″ is m-phenylene moiety, m-pyridinylene moiety, 3,4°-biph phenylene moiety, 4.3-biphenylene moiety, 3.3-biphenylene moiety or 2, A meta-oriented aromatic group such as a 6-naphthalene moiety. X and X' are preferably A sulfonyl moiety, an oxygen atom, a sulfur atom or an aliphatic group, more preferably a sulfonyl moiety. Honyl moiety or oxygen moiety. Most preferably, X is a sulfonyl moiety; X' is an oxygen atom.

The bonded AA/BB-monomer units most preferably have the following formula % The soft coil polybenzazole may be a bonded AB-polybenzazole. This includes a monomer unit represented by the following formula 11.

(In the above formula, the same rules as above except that X is not a bond) Soft coil polyurethane Benzazole contains aliphatic polybenzazole monomer units ( , which is expressed by the following equation 12(a) or (b).

(In the above formula, Ar' is an aromatic group suitable for AB polymers, and R1 is a Preferably, the aliphatic group contains aliphatic groups that do not interfere with its composition, processing and use. a divalent organic moiety consisting of a group other than those having the above meanings) Polybenzazole polymers include many known variations. For example, this polymer may contain a mixture of rigid, semi-rigid and soft monomer units. This is P It may contain both BO and PBT monomer units. different monomer units The groups contain different aromatic groups and/or different divalent organic moieties. various different monomers – Units may be included in the polymer in random, sequential or block arrangement .

A particularly desirable copolymer system is a block of soft coil polybenzazole A block copolymer containing blocks of rigid rod polybenzazole bonded to It is. The soft coil polybenzazole preferably has a bond having the above meaning. AA/BB-polybenzazole.

Polybenzazole polymers are known such as those described in the literature cited above. It is synthesized by the following method. This synthesis typically involves 50-120° at the beginning of the reaction. C, at a temperature that gradually increases and is 190-229 °C at the end of the reaction, AA-monomer in non-oxidizing dehydrated solvent acid in an inert atmosphere with vigorous stirring and BB-monomer condensation reaction, or AB-monomer self-condensation reaction.

Soft coil polybenzazole is the “5ynthesis” of Hedrick et al. ofImide-Aryl Ether Benzoxazole Rando m　Copolymers”, 30　PolymerPreprints　2 65-266 (1989) and Nucleoph of Inbasekaran et al. It is synthesized by aromatic nucleophilic substitution mechanism such as ilic.

Polybenzazole polymers contain AB- and/or AA/B-monomers. Including knit, polyamide, polyimide, polyquinoline, polyquinoxaline and / or preferably poly(aromatic ether ketone or sulfone) polymers. More complex random, sequential and block copolymers. Such copolymers and combinations thereof 9, Dahl et al.'s Aromatic Poly(Ether Ke tones) Having [m1de, Polybenzimidazol e Mo1ties, PCT Application No. 90103995 (1990 (April 19, 2016). A preferred copolymer is polybenzazole -Poly(aromatic ether ketone or sulfone) copolymer (hereinafter PEK- PBZ), which contains a benzazole moiety and a ketone and/or sulfone This is because it includes a sequence of aromatic groups bonded by an and/or an ether moiety.

A preferred example of a PEK-PBO copolymer is shown in Formula 20(a) below.

(In the above formula, each Y is a portion of 100- or -SO□, and a is the number of repeating units. , on average at least about 0.3 and less than 10, and B is greater than l block copolymer of polybenzazole and PEK-PBZ is preferably expressed by the following formula 20(b).

20(b) (In the above formula, each Y is independently a sulfonyl or carbonyl moiety, and each Ar is independently a is an aromatic group, each a is independently an average number of PBZ monomer units equal to at least about 10; , each number is at least equal to 1, and the number of summer plastic monomer units is at least equal to 1; Each m is the number of PBZ monomer units in each thermoplastic monomer unit; Equal to the average θ~3, C is the number of repeating PBZ and thermoplastic blocks at least equal to l) Membranes and their synthesis The present invention uses porous membranes. This porous membrane can be isotropic, asymmetric, or composite. That's fine. Isotropic membranes include one porous layer that functions as a discriminating layer. asymmetrical and The composite membrane includes a base layer and an identification layer.

The base layer is preferably thicker and has larger pores than the identification layer. asymmetric membrane In the method, the base layer and the identification layer have the same chemical composition.

In a composite membrane, the base layer and the discrimination layer have different chemical compositions.

The membrane is made of the above-mentioned polybenzoxazole or polybenzothiazole polymer or at least one copolymer (hereinafter collectively referred to as polybenzazole polymers) Contains seeds. If the membrane is a composite membrane, the polybenzazole polymer is present in the base layer or It may be in the identification layer or in both. The layer containing polybenzazole polymer is Poly(aromatic ether ketone) and poly(aromatic ether sulfone) poly coagulates with polymers or copolymers, such as polymers and polyamide polymers. The layer containing the polybenzazole polymer, which may contain other polymers, preferably contains other polymers. Contains no polymers. This layer more preferably consists essentially of one polybenzazo or polybenzothiazole polymers or copolymers.

The physical shape of the membrane does not matter. For example, the membrane may be a flat membrane or a medium It may be a hollow fiber or a tube.

The thickness of the membrane is limited by practical considerations. It is caused by tearing, pinholes, etc. fabricated without undesirable loss of retention and preferably at least about 5 μm; More preferably at least about 10 μm thick, preferably about 500 μm The thickness is more preferably about 300 μm or less. flat asymmetrical or double The coalesced membrane preferably has a thickness of at least about 10 μm, more preferably at least about 15 μm. m or less, preferably about 500 μm or less, more preferably about 300 μm or less It should be. The discriminating layer in an asymmetric or composite membrane preferably has at least about 0.1 μm, more preferably at least about 0.2 μm, preferably about 20 μm The thickness is more preferably about 1 μm or less. Hollow fiber isotropic or unpaired The internal diameter of the membrane is preferably at least about 50 μm and no more than about 5000 μm. and the outer diameter is preferably small (both about 60 μm and less than about 6000 μm). .

The membrane contains pores. The size of the pores depends on the purpose of the membrane and the layers of the membrane. Asymmetry too In other words, the base material layer of the composite membrane has very large pores, and the average discriminating layer of the ultrafiltration membrane The pore size is preferably at least about 20 angstroms, preferably less than about 500 angstroms, more preferably less than about 100 angstroms It is. The average pore size of the discriminating layer of the microfiltration membrane is preferably at least about 0. ．． 05 μm.

More preferably at least about 0.1 μm, preferably about 2 μm or less, more preferably Preferably it is about 0.2 μm or less.

The best method for producing membranes containing polybenzazole polymers is based on the desired Depends on the characteristics of

This membrane was made of 5ynthetic Polymeri from R, E, Kesting. c Membranes-2 edition 251-261 (J, Wiley & 5o Mixed phase inversion (1nvers 1on) method as described in NS 1985) formed by. Conditions for forming a film using a dope solution containing a polymer in a solvent acid Contact with non-solvent at . The solvent acid is preferably polyphosphoric acid (PPA) and/or or methanesulfonic acid (MSA), and optionally a small amount of P, 0□. most Preferably it consists essentially of polyphosphoric acid. The polybenzazole polymer is Synthesized by reaction of monomers in a medium acid. The polymer is directly precipitated from the resulting dope. It may be solidified to form a film. Alternatively, the polymer or copolymer is obtained from a polymerized dope. It may be precipitated and redissolved to form a second dope solution suitable for membrane synthesis.

The dope may contain a mixture of different polybenzazole polymers. Also, the membrane In the conditions used for production, the solvent is stable in the acid and PBO and/or May contain polymers other than PBO and PBT that co-precipitate with the PBT polymer .

Examples of solutions containing mixtures of PBO and/or PBT polymers and other polymers include: IJY's 5 pinnable Dopes and other Article esTh, erefrom, U.S. Patent No. 4.810.735 (March 1989) 7th). Preferred polymers are polyamides and polyaromatic ethers. Contains Luketone. Most preferably, the dope is PBO and/or PBT polymer or does not contain polymers other than copolymers.

The concentration of polymer within the dope allows the dope to be processed and the film to have acceptable physical properties. should be selected so that it can be formed. At very low concentrations, the dope is uniform Does not contain enough polymer to form a membrane. At very high concentrations, the dose The paste is too viscous to use. The optimum concentration is the polymer and solvent acid in the dope, Depends on desired film properties and processing method.

Unlike the system described in Kesting, a drug containing polybenzazole The viscosity is high at relatively low polymer concentrations; A porous structure is formed without the need for pore-forming compounds other than the agent. given de The viscosity of the polymer chain depends on the chosen solvent acid, the chemical composition of the polymer, and the rigidity of the polymer backbone. Many factors such as the degree of polymerization of the polymer, the concentration of the polymer, and the liquid crystallinity of the dope solution It depends on the cause. Those skilled in the art can discover optimal conditions without undue experimentation. You can adjust these factors.

Cast membranes are made by coating a dope onto a base material such as glass or a base membrane to achieve the desired thickness. The dope is spread evenly over the area, and this dope is brought into contact with a diluent and coagulated. more synthesized. Cast membranes are preferably formed from a more dilute dope than extruded membranes. . The concentration of hard rod polymer within the MSA or PPA dope is preferably low. at least about 0.5 percent by weight, more preferably at least about 1.0 percent by weight It is

Extrusion membranes pass the dope into an extrusion die in the form of a hollow tube, for example. It is formed by pushing it across a space and into a coagulation bath. hollow fiber is It is spun and pulled out from a hollow die (spinner 0). The spun dope is sent to a coagulation tank coagulate within the fibers to form coagulated fibers. Such a method is described in 12 Kirk- Othmer Ency, Chem.

Tech, Hollow Fiber Membranes, 492 ( J. Wiley & 5ons 1981). Polymer concentration The temperature is usually higher than that of cast membranes. it is often at least about 1% . The concentration of hard rod polymer within the MSA or PPA dope is preferably about 5 0 weight percent or less, more preferably about 40 weight percent or less, most preferably or less than about 16 weight percent. Broth of hard and soft polybenzazole The preferred concentration of the block copolymer is such that the block copolymer is rigid at the same concentration. If it has a higher viscosity than polyben oazole, it is lower.

The doped film is subjected to known methods such as tentering or bubble formation before solidification. more stretched. The film extrusion and stretching method is described by Harvey et al. in Biaxia lly 0iented 0rdered Polymer Fil+ns, PCT International Application No. WO89/12072 (December 14, 1989) , Harvey et al. (February 6, 1990). Stretching is uniaxial or may be biaxial. Stretching is considered to have no substantial effect on the porosity of the resulting membrane. However, it is thought to increase the flow through the membrane.

Coagulation of the polymer to form a film involves contacting the dope with a non-solvent diluent This is achieved by A diluent reduces the solubility of a polymer in a solvent acid and Any liquid that solidifies. This may be organic or aqueous. stomach. The aqueous diluent may contain a base or even a small amount of a weak acid, but at the start Conveniently, it is water. After solidification, the polymer is washed in water to a practical extent residual solvent is removed. Washing may continue for 24 hours or more.

The coagulated form of the polymer is free from open air, which retains microbubbles as long as the polymer remains wet. Forms a foam structure. This open structure can be operated as a porous membrane. bubble size are usually suitable for ultrafiltration and/or microfiltration. The bubble size is determined by the amount of poly in the solvent. This can be varied by changing factors such as concentration of mer and choice of coagulation bath.

Coagulated from a dope containing 14 percent hard rod polybenzazole polymer The average cell size of the membrane is preferably about 35 angstroms or less, more preferably about 35 angstroms or less. Preferably, it is about 30 angstroms or less. The average cell size is preferably about 2 It is 5 angstroms or more.

Approximately 3% of the rigid rods and combined polybenzazole block copolymer The flux of the coagulated film from the dope containing the agent is preferably at least as low as for clear water. is also about 100 mN/(ca+”)(hrXcmHg).The average bubble size is preferably about 35 angstroms or less, more preferably about 30 angstroms It is as follows. The average cell size is preferably about 25 angstroms or greater.

When the membrane is oven dried, porosity is often undesirable. shrinks to a size so small that it does not release after rewetting the membrane. wet again The membrane may be lyophilized to provide open cells. However, freeze-dried membranes It is also brittle and usually exhibits lower flow and/or lower retention than the initially produced membrane.

Membranes produced by phase inversion are preferably kept moist from the end of their use until solidification. left alone.

Conditions of coagulation may be varied to provide isotropic or asymmetric films. Gather one side of the membrane. membranes while preventing contact with impermeable phases such as glass or Teflon polymers. When contacted with a diluent, the membrane usually has large air bubbles concentrated in the body of the membrane and on one side of the membrane. The result is an asymmetrical structure with small air bubbles.

Membranes with large cell sizes are described in Kestin H, 303-305. It is formed by a similar leaching method. In the leaching method, solvent acids, polybenzoa A homogeneous dope solution containing a sol polymer and a bubble-forming compound is is contacted with a diluent that coagulates the copolymer and the cell forming compound. Then bubble shape The compound is leached using a solvent that does not dissolve the polybenzazole polymer.

Cell-forming compounds are compatible with solvents and solvent acids that do not dissolve the polybenzazole polymer. Must be soluble. It should be precipitated under the same conditions that precipitate the polymer. It is possible. It preferably does not react with solvent acids. Suitable bubble-forming compounds are e.g. For example, bisphenol A, triphenylmeth/-, phenylthiazine, 2- Methoxynaphthalene, ethyl-4-1 nitroxybenzoate, 2,5-dife Contains niloxazole, or low molecular weight bisphenol A epoxy resin.

Bubble-forming compounds tend to co-precipitate with polymers in separate membranes when acid is diluted be. , the size of the two phases determines the average cell size of the resulting porous product. air The selection of the foam-forming compound depends on the size and size of the zone of the foam-forming compound within the solidified polymer. Significantly affects the average cell size of porous products. Generally, PBO or Cell-forming compounds that are highly compatible with PBT polymers include PBO or PBT polymers. Forms smaller bubbles than bubble-forming compounds that are less compatible with polymers. For example, mind Porous products manufactured using benzophenone as a foam-forming compound are with larger bubbles than those formed using bisphenol A as a compound Ru.

The dope solution is coagulated and washed as described above. No bubble-forming compounds Unlike membranes that are coagulated with a cell-forming compound, membranes that are coagulated with a bubble-forming compound are preferably completely solidified. fully or partially dried. If the membrane is completely dried before the leaching process, the PBO port The rimmer is substantially rigid during the leaching process, and air bubbles within the membrane do not initiate leaching and The resulting membrane usually has a large cell size. If the membrane is only partially dried, The PBO remains soft and the bubbles are partially submerged, resulting in a small average bubble size. .

The membrane is made of organic material that can dissolve the bubble-forming compounds for a sufficient period of time to allow them to leach out. Contacted with solvent. This solvent does not dissolve PBO or PBT polymers. It should be. This solvent is preferably volatile and the resulting porous product can be easily removed. Examples of suitable solvents are acetone, methanol, and methyl chloride. Including Ren.

Membranes synthesized by the leaching method can be thick enough to act as an identification layer or act as a base layer. It has sufficient thickness. This membrane typically has an open cell structure. average mind The bubble size is about 1 micron to about 200 microns. Average bubble size is preferred is at least about 3 microns, more preferably about 100 microns or less.

Apparatus and method for using membranes The membrane produced by either method may be used for known applications of porous membranes. . When using this as an identification layer, it is bonded to a known base layer to form a composite film, Alternatively, it can be used without a substrate if it is strong enough to withstand the pressure gradient across the membrane. It's okay to stay. When used as a base layer, it must be bonded to the identification layer to form a composite film. do not have.

Typically, the final membrane is separated by a membrane, whether isotropic, complex or asymmetric. is placed in an apparatus containing a high-pressure zone and a low-pressure zone. This zone is the membrane The material is arranged so that it moves from a high pressure zone to a low pressure zone by passing through the It will be done. The specific characteristics of the zone depend on the properties of the membrane. For example, hollow fiber or For tubular membranes, the high pressure zone is inside the fiber and the low pressure zone is outside. Ru. In a flat membrane, the high pressure zone is located on one side of the membrane and contains a low pressure seamable component. The feed mixture is contacted with the membrane in a high pressure zone. Liquid components must pass quickly through the membrane. Must be. It usually contains separable hydrogen and halogenated hydrocarbons. separation The possible components have molecular weights high enough that most of the separable components do not pass through the membrane, or It has a large particle size. Such conditions affect the uniformity and pore size of the membrane. Judgment is made without reference to average bubble size. However, preferably the membrane separates at least about 50 percent, more preferably at least about 80 percent of the possible ingredients. percent, most preferably at least about 95 percent.

It depends on many factors like the physical form it is involved in. For example, different membranes and equipment, the pressure difference (pressure across the membrane) between the high and low pressure zones is small. at least 1 psi (70 g/cm”), or at least 10 psi (70 g/cm”) 0 g/cm”) or at least 100 psi (700/am”) or It is more than that. Those skilled in the art will know without undue experimentation whether a particular membrane and It is collected as a flow. The separable components are recycled as a concentrated stream from the high pressure zone. may be collected.

The flux of separable components through the membrane is a function of the conditions in which the membrane is used, the bubble size and the density. Depends on many factors like. The flux of clean water through the ultrafiltration membrane is or at least about 20 m1/(m”) (hr) (cmHg), more preferably preferably at least about 30 m1/(msu (hrXcmHg), most preferably at least about 100 m1/(m”Xhr) (cmHg). The flux of clean water is preferably at least about 200 m/(m”) (hr ) (cmHg).

Many methods are known for carrying out such methods. For example, around a flat membrane Secure the outer edge of the membrane to a supporting frame structure. This frame is a screen that supports the membrane. It also supports the community. Membranes may be attached by clamping mechanisms, adhesives, chemical bonding, or other methods. may be fixed to the frame structure. This frame also has a screen that supports the membrane. This supporting membrane is designed so that the internal membrane surface of the frame structure is connected to two non-communicating areas within the container. It may be fixed in a conventional manner within the container so as to separate the regions. Those skilled in the art will understand that the structure supporting the membrane is It will be appreciated that the structure may be the internal inlet of the container or the external end of the membrane.

The membrane separates a high pressure zone on one side of the membrane into which the feed mixture is introduced from a low pressure zone on the other side. Let go. The membrane is in contact with the feed mixture under pressure, while maintaining a pressure differential across the membrane. dripping

Preferred methods for the use of flat, hollow tubes and hollow fiber membranes and 225-248 (D, Redel Publ, 1986); Aptel et al., 'Ultr afiltration”.

The following examples are illustrative only and are not intended to limit the scope of the specification or claims. . All parts and percentages are by weight unless otherwise indicated.

Leachable porous sheet manufactured using snore-benzoic acid with an intrinsic viscosity of 21.1 dL/g Powdered cis-PBO having a certain degree of Understand. This solution is mechanically shaken for 24 hours to obtain a homogeneous, clear, brown solution.

This solution is cast onto a glass plate using a 12 mil gap cast caster. Also This solution was cast using a casting rod with a gap of 12 mils from AWA Company in Japan. Cast onto the resulting 3.8 mil thick 5anko substrate. Immediately add 1 piece of each cast film. Soak in water at 5°C for at least 4 hours.

5. Peel off the film that will not be cast onto the anko substrate from the glass plate, and Paste it on the sheet. Each film was dried in air for 16 hours, then the film was dried on Teflon. Cut the lume from the Teflon sheet. Cut each film into samples. each sun The pulls are soaked in methanol for 30 minutes and then dried in air at room temperature for about 2 hours.

The film cast on 5anko base material E was subjected to N1kon 0ptiphoto transmission light microscopy. Observe using a microscope. This observation indicates that this film has an average bubble density as shown in Table I. It has been shown to have a Weigh the film cast on glass and show in the table There was a loss of weight.

carpenter Sumburu Weight ratio Base material % weight loss Average cell size 2 0.5/3010 5anko dense film 3 0.5/30/1 glass 53.64 0.5 /30/I 5anko 155 0.5/30/2 Glass 74.16 0 ．． 5/30/2 5anko 257 0.5/30/4 Glass 84.28 0.5/3015 5anko 50M Leaching produced using benzoic acid Porous Sheet Using the method of Example 1, 130 parts of methanesulfone with 0.3 parts of PBO A solution containing acid and 3.2 parts of benzoic acid is cast onto a glass plate.

Examining the membrane with an optical microscope reveals a network of interconnected open cells. was shown to be configured.

Flood - 130 parts of PBO in 0.5 parts of leachable porous sheet made with benzoic acid of methanesulfonic acid and 4 parts of benzoic acid were prepared according to the method of Example 1. and cast onto a 3.8 mil thick 5anko substrate using a 12 mil gap casting caster. do. Each was dried for the time indicated in Table 1 before being immersed in methanol. can get Observation of the film showed the bubble sizes shown in Table 3.

Table π 11 ~ 960 50 Example” - Example of use of membranes manufactured by leaching method 1 (7) Samples 4 and 6 The membrane was placed in an Amlcon Model 8050 5cc stirring cell. supply As a flow, 0.091 μff! , 0.173 μm, 0.215 am , 0.527 am, and o, 5 with an average latex particle size of 913 μm. Test the permeability of each layer using seed 0.3 percent polystyrene latex. Ru. Permeation is tested at room temperature at a pressure of 20 psig. Collect the permeate, and Analyze the turbidity by minutes and analyze the concentration of polystyrene latex. This membrane is Shows the characteristics shown in Table ■. Permeation is gallons/ft”-dad (GF D).

Table■ Sample retention flux (GFD) 475% 0.913 μaa 1.2 635% 0.913 am 2.7 Flooding - Leachable porous membranes made with other pore-forming compounds instead of benzoic acid Example 1 using benzophenone (BZPN) and bisphenol A (bis-A) Repeat the method. The results are shown in Table ■.

Table■ Sumbuga bubble formation weight ratio base material after leaching average compound PBO/MSA/ Bubble formation Weight loss % Bubble loss 12 BZPN O, 5/30/1 Glass 31 ．． 313 BZPN O, 5/30/I 5anko 1514 BZPN O , 5/30/2 Glass 72.215 BZPN O, 5/30/2 5an ko 2016 bis-A 0.5/30/1 glass 53.517 bi s-A O, 5/30/I 5anko 818 bis-A 0.5/30/ 2 Glass 71.619 bis-A 0.5/30/2 5anko 10 The experiment of Example 4 is repeated using membranes of Samples 15 and 19. This film is shown in Table ■ Shows transmission characteristics.

Table V Sample retention flux (GFD) 1565% 0.913 μm 1.8 1940% 0.913μm 1.5 Example 6 - Phase inversion membrane with hard rod polymer Two polybenzoxazole polymers -Synthesize the dope by the following method. 138 containing about 76% PzOs 7 g polyphosphoric acid (PPA), 300 g 4,6-diamylsorcinol bis( hydrochloride) (DAR), 233g terephthalic acid (TA), 0.4g A mixture of benzoic acid (BA) and 539 g of phosphorus pentoxide (PO) was added under a nitrogen atmosphere. , add to a batch reactor equipped with a stirrer. The ratio of reactants is approximately 83.5 weight PPA % P2O, and the final dope is about 14% by weight. selected to give a reaction mixture containing 50% of the polymer.

Each mixture was stirred at 80-85 °C for 20 minutes with heating under nitrogen flow, then Increase the temperature to 105-115°C for 10-12 hours and then again to 120-130°C. Let rise for about 2 hours. During the last 2 hours the reaction is carried out under vacuum. Under vacuum, 150-1 At 90°C, the dope is transferred to a piston-stirred reactor and in this reactor Incubate at about 190℃ under vacuum for about 0.5 to 2 hours until the viscosity in the reactor becomes stable. continue to respond.

Barrel temperature of approximately 190°C, barrel pressure of approximately 1740 psig, and temperature of approximately 170°C. set to 0.001 inch using die temperature and die pressure of approximately 1 l and 100 psi. Extrude the sample through a flat die extruder. To facilitate handling , the extruded film is coated with two sheets of Teflon with a thickness of 0.002 to 0.003 inches. Place it between the tubes.

One sheet of Teflon was peeled off from each sample and stretched by hand on the ring for 5 days. Stretch. Peel off the Teflon sheet on the other side from each sample, and Immerse the pull in water. Cut a circular membrane (25 cm in diameter) from each film. each Mount the sample on an Amacon Model 18010 stirred membrane holder. 1 Place distilled water on top of the membrane holder under 0 psig nitrogen pressure and collect the permeate. , to weigh. This method uses a 4 weight percent solution of bovine albumin in distilled water. repeat. Bromeresol Green Collect with a dye and stain all the albumin in the permeate. At about 628nm Measure the absorbance of the solution using a spectrophotometer. This absorbance is measured using a known standard for albumin. Compare the absorbance of the quasi-solution to determine the retention of the solution.

The first sample was 31.6 ml/(ga) (hr) (emHg) in clear water. and a flux of about 20.6 ml/(mHg) in the rubumin solution. ) represents the flux of The second sample was 31.6ml/(m”Xhr) in clear water. (cdg) and approximately 20.6 ml of water containing 4 weight percent albumin. /(mri (hr) (cmHg). The second sample shows a flux of 97% indicates the exclusion of a component.

Example 7 - Phase reversal membrane (1) containing approximately 76 pamphlets of hard rod-soft coil block polymer. -St. P, 0. 1500g polyphosphoric acid (PPA), (21634g Bis-(4-hydroxy-3-aminophenyl)sulfone bis(hydrochloride) ) (BHAPS), (3) 48.9 g of oxy-bis-(4-benzoic acid) (O BBC), (41505 g of phosphorus pentoxide (P, Os), and (5) 9:10 mo ratio of terephthalic acid and 4,6-diamylsorcinol bis(hydrochloride). 14 weight percent hard rod cis polyben in polyphosphoric acid obtained by reaction 500g of dope containing zooxazole The mixture is added to a batch reactor equipped with a stirrer under a nitrogen atmosphere. Ratio of reactants The PPA initially contains about 2 weight percent P2O, and the final dope is The reaction mixture is selected to provide a reaction mixture containing about 6 weight percent polymer. This mixture Heat the material to 80-100°C for about 4 hours with stirring, then pause, and then heat for 2 days. Heat. The mixture is placed under vacuum (less than 1 torr) and heating is continued for 4 hours.

Transfer this mixture to a piston stirred reactor. 5 times over 4 days at 190°C The reaction was continued for a total of about 11 hours. Divide the resulting mixture into two parts, the second part dilute with PPA and PO to a concentration of 3 weight percent.

Barrel and die temperature of about 190°C, barrel pressure of about 2370 pSig and about 6 6 percent sample by the method described in Example 6 at 50 psig die pressure. Push the film out. Barrel and die temperature of approximately 180°C, approximately 1500p sig barrel pressure and a die pressure of about 190 psig. Extrude the film from the 3 percent sample by. Those with film are circles. The shapes are stretched by hand using the weight of the wheels, while the others are stretched by machine while remaining between Teflon sheets. , and others remain unstretched. Each is allowed to coagulate in a water bath.

Membrane flux for distilled water and flux and rejection for bovine albumin are described in Example 6. Measure as follows. Three unstretched membranes have a resistance of 217.208 and It has a flux of 185 m1/(m”Xhr) (emHg) for albumin solution. It has a flux of 128.75 and 76 m1/(ga) (hr) (cmHg). Ru. A membrane stretched three times its initial radius in a direction perpendicular to the direction of extrusion becomes transparent. A flux of approximately 100.5 ml/(m”) (hrXcmHg) for water, and It has a flux of approximately 48 m1/(m"Xhr) (cmHg) for the min solution.

Each membrane exhibited greater than 95 percent rejection of albumin.

Example 8 - Asymmetric film containing a mixture of hard rods and soft PBO 4.6-diamide Obtained from the reaction of lusorcinol bis(hydrochloride) and terephthalic acid, 27 A hard rod cispolybenzoxazole with an intrinsic viscosity of ~33 dL/g was obtained. It will be done. Commercially available poly(aromatic ether ketone) (PEEK) polymers are [C[C orp under the trade name PEEK 450-P. These two weigh about 2 The proportions shown in Table ■ in sufficient quantities to form a dope solution containing % of the polymer Add to methanesulfonic acid. Solutions with particularly high viscosity can be heated to facilitate casting. do. Gently roll the cast stone along the length of the cast stone, set to a thickness of 0.03 inch. The dope is placed on the heated glass plate by drilling and moving at a constant speed. Pour. Put mask tape around the film and dope from the plate side. Prevent dilution due to leakage. Place each plate at a 30° angle in water (H2O) or acetate. It is immersed in a coagulation bath containing nitrile (MeCN) for 1 to 2 minutes until coagulation is completed.

Each film is then peeled off from the plate, washed with water, and stored by immersing it in water.

Cut the membrane from a thin spot or other defect-free area from each film. transparency and retention were determined as described in Example 5 and are shown in Table ■.

Those with membranes are freeze-dried by the following method. Place the wet membrane between two pieces of filter paper. and fix the whole thing. Sprinkle a thin layer of powdered dry ice on top of the filter paper1, then add Sprinkle with seton. Use powdered dry ice and acetone on both sides of the filter paper for 2 minutes. Repeat for a while. The membrane and filter paper were then cooled in a 600 ml L Place in an abconco lyophilization flask. This flask is connected through a condenser. Connect to a vacuum pump and place under vacuum while cooling with dry ice overnight. optics and Electron microscopy reveals that each film has an open-cell structure on one side and dense pores on the other side. It is shown that it has a structure with low properties. Transparency and retention were as described in Example 5. The results are shown in Table ■.

abstract Polybenzoxazole, polybenzothiazole and/or copolymers thereof Polytopic membranes comprising: and methods of making and using the same are disclosed.

international search report

Claims (1)

[Claims] 1. (1) High pressure zone, (2) low pressure zone, and (3) Porous membrane a membrane separator comprising: a membrane separator in which said element is energized by permeation through the porous membrane; The porous membrane is arranged to pass from the pressure zone to the low pressure zone, and the porous membrane Zooxazole polymer or copolymer or polybenzothiazole polymer Or a membrane separation device characterized by containing a copolymer. 2. at least one low molecular weight fluid component and at least one separable component; A method for separating a mixture containing a membrane, the mixture comprising: of suitable size to exclude at least a portion of the separable components at a pressure of The porous membrane is contacted with a porous membrane having pores, and the porous membrane is made of polybenzoxazole polymer. or copolymers or polybenzothiazole polymers or copolymers. A method characterized by: 3. Polybenzoxazole polymer or copolymer or polybenzothiazo A porous hollow fiber membrane comprising a polymer or copolymer. 4. Polybenzoxazole or polybenzothiazole polymer or copolymer A film having a layer containing polybenzoxazole or polybenzo The membrane having a layer containing a thiazole polymer or copolymer is 500 microns or more. Open-cell structure with a thickness of 1-200 microns and an average cell diameter of 1-200 microns A membrane characterized by having: 5. Polybenzoxazole or polybenzothiazole polymer or copolymer is essentially (a) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (b) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (c) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (d) ▲ Numerical formulas, chemical formulas, tables, etc. etc. ▼, (e) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above formula, each Z is an acid is an elementary atom or a sulfur atom, L is -Arm- or -Ar-X'-Ar-, Each Ar and Ar2 is an aromatic group, Arm is a metaaromatic group, and X and X' are each independently a sulfonyl group, an oxygen atom, a sulfur atom or an aliphatic group) Any one of the preceding claims, consisting of a repeating monomer unit represented by one of The invention described. 6. Polybenzoxazole or polybenzothiazole polymer or copolymer Ma is below formula (a) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (b) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (c) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, (d) ▲ Numerical formulas, chemical formulas, tables, etc. etc. ▼, (e) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the above formula, each Z is an acid is an elementary atom or a sulfur atom, L is -Arm- or -Ar-X'-Ar-, Each Ar and Ar3 is an aromatic group, Arm is a metaaromatic group, and X and X' are each independently a sulfonyl group, an oxygen atom, a sulfur atom or an aliphatic group) Any one of claims 1 to 4, comprising at least a plurality of monomer units represented by one of The invention described in any of the above. 7. Any of claims 1 to 6, wherein the membrane is an isotropic membrane consisting essentially of one discrimination layer. The invention described in 8. Claims 1 to 6, wherein the membrane is an asymmetric membrane or a composite membrane comprising a base layer and a separation layer. Any of the inventions described above. 9. The membrane has an average inner diameter of 50 to 5000 μm and an average outer diameter of 60 to 6000 μm. The invention according to any one of claims 1 to 8, which is a hollow fiber membrane. 10. Claims 1, 2, wherein the membrane is a flat membrane with an average thickness of 5 to 500 μm. Or the invention according to any one of 4 to 8. 11. The membrane has an average cell size of 20 to 500 angstroms in the discrimination layer. The invention according to any one of claims 1 to 3 or 5 to 10, which is an ultrafiltration membrane. 12. The membrane has an average bubble size of 0.05 to 2 μm in the micro layer. The invention according to any one of claims 1 to 3 or 5 to 10, which is a filtration membrane. 13. Polybenzoxazole or polybenzothiazole polymer or copolymer Claims 1 to 3, wherein the layer of the membrane comprising the remer has an average cell size of at least 2 μm. The invention according to any one of Items 3 and 5 to 10. 14. Claims 1, 2, wherein the pressure across the membrane is at least about 70 g/cm2. Or the invention according to any one of 4 to 13. 15. (1) Solvent acids, PBO or PBT polymers, and solvent acids and organic acids forming a homogeneous solution containing pore-forming compounds that are soluble in water but insoluble in water , (2) PBO or PBT polymer and pore-forming compound co-precipitate and PBO or a film containing separate zones of PBT and separate zones of pore-forming compounds. Aqueous dilution of the homogeneous solution of step (1) under conditions such that a film or film is formed. and (3) dissolving the pore-forming compound from the film or membrane. The film or membrane of step (2) is contacted with an organic solvent to give it a porous structure. to let A method for producing a porous membrane, comprising the steps of: