Background technology
Milipore filter is a kind of aperture specification unanimity, and specified pore diameter range is the micropore filtering film of 0.001-0.02 micron.Side at film imposes suitable pressure, just can sift out the solute molecule less than the aperture, with the isolated molecule amount greater than 500 dalton, particle diameter particle greater than 2~20 nanometers.Milipore filter can be used for separating, concentrates, purifying biological goods, pharmaceutical products and food industry; The terminal processes device that also is used for blood processing, wastewater treatment and ultra-pure water preparation.Milipore filter comprises symmetric membrane and anisotropic membrane according to the difference of structure.The former is isotropic, does not have cortex, and the hole on all directions all is the same, belongs to in-depth filtration; The latter has fine and close top layer and based on the bottom of finger, skin depth is 0.1 micron or littler, and has the orderly micropore of arrangement, and underlayer thickness is 200~250 microns, belongs to both surface filtration.The milipore filter that industry is used is generally anisotropic membrane, as hollow-fibre membrane (hollow fibermembrane).The hollow-fibre membrane profile has the self-supporting effect as fibrous.Its compacted zone can be positioned at the outer surface such as the reverse osmosis membrane of fiber, also can be positioned at the inner surface (as micro-filtration membrane and milipore filter) of fiber.The membrane material of milipore filter mainly contains polyvinyl alcohol, modified acrylic polymer of cellulose and derivative thereof, Merlon, polyvinyl chloride, Kynoar, polysulfones, polyacrylonitrile, polyamide, polysulfonamides, SPSF, interlinkage or the like.Polyvinyl chloride is one of three big synthetic resin of current production rate maximum, in China stable raw material supply is arranged, and has cheap, premium properties such as chemical stability good, acid and alkali-resistance, is widely used in the preparation of milipore filter.
Polyvinyl chloride is a kind of macromolecular material that uses a chlorine atom to replace a hydrogen atom in the polyethylene, yet the pvc material hydrophily is relatively poor, and relatively poor with its milipore filter contamination resistance of making, The decline of membrane flux is serious.In the prior art, adopted several different methods to handle the polyvinyl chloride milipore filter and attempted to improve its hydrophilicity.These methods comprise: blending modification method, surface preparation, surface graft modification method etc., they are in the hydrophily of having improved the polyvinyl chloride milipore filter in varying degrees, yet along with the modification degree increases, cause membrane material intensity to weaken.But because for hollow-fibre membrane, film-strength is provided by separation membrane material self fully, the practicality of diffusion barrier is not only relevant with separation function, and is simultaneously closely related with film-strength, and this has just limited the preparation of high score from functional film material greatly.Therefore, along with the development of membrane technology, composite membrane technology has entered milipore filter research.
Chinese invention patent CN100417434C discloses a kind of preparation method of composite hollow fiber membrane, with polyether sulfone or polysulfones casting solution basement membrane spinning solution as composite hollow fiber membrane, Kynoar or its copolymer casting solution spin out high strength, the compound doughnut perforated membrane of high-throughout hydrophily as the composite bed spinning solution.In addition, Chinese invention patent CN101623601A also discloses a kind of preparation method of composite hollow fiber membrane, with polyvinyl chloride or its copolymer casting solution basement membrane spinning solution as composite hollow fiber membrane, Kynoar or its copolymer casting solution spin out the compound doughnut perforated membrane that cost is low, mechanical strength is high as the composite bed spinning solution.These compound hollow fiber ultrafiltration membrane have been improved the preparation method of non-composite hollow fiber membrane, improve the performance of hollow fiber ultrafiltration membrane, reduce raw-material Costco Wholesale, have enlarged the application of milipore filter.Yet preparation material from the compound hollow fiber ultrafiltration membrane of these prior aries, no matter be basal lamina material, still composite material, all usefulness is hydrophobic material, need add a large amount of pore formers in casting solution and hydrophilizing agent just can be prepared high-throughout hollow fiber ultrafiltration membrane.This causes the prolongation along with service time, and membrane flux is seriously decayed, and influences the stability that milipore filter uses.
Summary of the invention
The object of the invention is to provide a kind of composite polrvinyl chloride hollow fiber ultrafiltration membrane, it is low to have solved in the prior art polyvinyl chloride hollow fiber ultrafiltration membrane intensity, The decline of membrane flux is serious, the shortcoming of poor toughness provides a kind of intensity height, flux is big, rejection is high, pliability is excellent composite polrvinyl chloride hollow fiber ultrafiltration membrane.
In order to solve these problems of the prior art, technical scheme provided by the invention is:
A kind of composite polrvinyl chloride hollow fiber ultrafiltration membrane is characterized in that described milipore filter prepares by the following method:
(1) polyvinyl chloride, pore former, solvent are pressed following mass percent:
Polyvinyl chloride 10%~25%;
Pore former 2%~5%;
Solvent 70%~88%;
Evenly mixing, dissolving, filtration, deaeration preparation quality concentration are the basement membrane liquid of the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 10%-25%;
(2) hydrophilic polymer, pore former, solvent are pressed following mass percent:
Hydrophilic polymer 15%~25%;
Pore former 2%~5%;
Solvent 70%~83%;
Evenly mixing, dissolving, filtration, deaeration preparation quality concentration are the composite bed casting solution of the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 15%-25%;
(3) the composite bed casting solution of the basement membrane liquid of the composite polrvinyl chloride hollow fiber ultrafiltration membrane that step (1) is prepared and step (2) preparation is 1 with volume ratio: 100-100: 1 ratio, extrude the tubulose liquid film by the spinneret of doughnut spinning-drawing machine simultaneously with the inner gel medium, this liquid film solidifies, makes through washing, drying the composite polrvinyl chloride hollow fiber ultrafiltration membrane through entering behind 0-20 centimetre the air-gap in the outer setting medium.
Preferably, described polyvinyl chloride polymerization degree is 600-3000.
Preferably, described hydrophilic polymer is selected from a kind of in cellulose diacetate, Triafol T, polyvinyl alcohol, vinyl chloride-vinyl acetate bipolymer, chloroethylene-vinyl acetate-maleic acid acid anhydride terpolymer, vinyl chloride-vinyl acetate-vinyl alcohol terpolymer, ethylene-vinyl acetate copolymer, the polyvinyl butyral resin.
Preferably, described pore former is a kind of in polyvinylpyrrolidone, the polyethylene glycol or both mixtures, and described polyvinylpyrrolidone is to be selected from the polyvinylpyrrolidone that model is K12, K17, K25, K30, K60, K90; Described molecular weight polyethylene glycol scope is 200-20000.
Preferably, described solvent is a kind of in dimethyl formamide, dimethylacetylamide, the N-methyl pyrrolidone or both mixtures.
The present invention also provides a kind of preparation method of composite polrvinyl chloride hollow fiber ultrafiltration membrane, it is characterized in that said method comprising the steps of:
(1) polyvinyl chloride, pore former, solvent are pressed following mass percent:
Polyvinyl chloride 10%~25%;
Pore former 2%~5%;
Solvent 70%~88%;
Evenly mixing, dissolving, filtration, deaeration preparation quality concentration are the basement membrane liquid of the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 10%-25%;
(2) hydrophilic polymer, pore former, solvent are pressed following mass percent:
Hydrophilic polymer 15%~25%;
Pore former 2%~5%;
Solvent 70%~83%;
Evenly mixing, dissolving, filtration, deaeration preparation quality concentration are the composite bed casting solution of the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 15%-25%;
(3) the composite bed casting solution of the basement membrane liquid of the composite polrvinyl chloride hollow fiber ultrafiltration membrane that step (1) is prepared and step (2) preparation is 1 with volume ratio: 100-100: 1 ratio, extrude the tubulose liquid film by the spinneret of doughnut spinning-drawing machine simultaneously with the inner gel medium, this liquid film solidifies, makes through washing, drying the composite polrvinyl chloride hollow fiber ultrafiltration membrane through entering behind 0-20 centimetre the air-gap in the outer setting medium.
Preferably, described method step (1) polyvinyl chloride or its copolymer or the mixture of the two, pore former, solvent mix under 30 ℃-90 ℃, stirring condition and dissolve, and the solution that obtains after filtration, obtain the basement membrane liquid that mass concentration is the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 10%-25% after the deaeration; Hydrophilic polymer in the described method step (2), pore former, solvent mix under 30 ℃-90 ℃, stirring condition and dissolve, and the solution that obtains after filtration, obtain the composite bed casting solution that mass concentration is the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 15%-25% after the deaeration.
Preferably, the basement membrane liquid of composite polrvinyl chloride hollow fiber ultrafiltration membrane and the volume ratio of composite bed casting solution are 1 in the described method step (3): 20-20: 1.
Preferably, in the described method step (3) hollow fiber ultrafiltration membrane that makes is washed immersion under 10 ℃-40 ℃ condition, promptly get the composite polrvinyl chloride hollow fiber ultrafiltration membrane to remove solvent and the part pore former in the casting solution system, to dry again.
Inner gel medium described in the described method is that the mass concentration under 10 ℃-40 ℃ of the temperature is the 0-30% solvent aqueous solution; Described extrusion temperature is 20 ℃-60 ℃; Described air-gap condition is: 10 ℃-40 ℃ of temperature, relative humidity 30%-99%RH; Described outer gel media is that the mass concentration under 10 ℃-40 ℃ of the temperature is the 0-50% solvent aqueous solution.
Adopt casting solution that polyvinyl chloride, pore former, solvent are made basement membrane liquid in the technical solution of the present invention as compound hollow fiber ultrafiltration membrane, the casting solution that hydrophilic polymer, pore former, solvent are made is as the composite spinning liquid of compound hollow fiber ultrafiltration membrane, with the composite spinneret extrusion molding of two kinds of spinning solutions, make the composite polrvinyl chloride hollow fiber ultrafiltration membrane by the doughnut spinning-drawing machine.
Because what the technical solution of the present invention ectomesoderm used is hydrophilic polymer, when this composite membrane uses as the external-compression type film, the performance that obviously is better than common polyvinyl chloride hollow fiber ultrafiltration membrane is arranged.And the polymer on composite polrvinyl chloride hollow fiber ultrafiltration membrane surface is hydrophilic, make this composite membrane low to the absorption of albumen, be difficult for polluting and fouling, improve the contamination resistance of film, improve the stability in use of film, along with the prolongation of service time, it is not obvious that the The decline of membrane flux phenomenon also can become, and improves the serviceability of film simultaneously.Because the compatibility of polyvinyl chloride and hydrophilic polymer is good, form the interface finger-like pore at basement membrane and composite bed interface energy, increase the flux of polyvinyl chloride hollow fiber ultrafiltration membrane.Compare with conventional polyvinyl chloride hollow fiber ultrafiltration membrane hydrophilic modifying, composite membrane technology of the present invention has improved basement membrane intensity, flux, contamination resistance, improves the stability in use of film.
The preparation method of composite polrvinyl chloride hollow fiber ultrafiltration membrane of the present invention may further comprise the steps:
(1) preparation of basement membrane casting solution: polyvinyl chloride, pore former, solvent are mixed under 30%-90 ℃, stirring condition and dissolve, the solution that obtains after filtration, obtain the basement membrane liquid that mass concentration is the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 10%-25% after the deaeration;
(2) preparation of composite bed casting solution: hydrophilic polymer, pore former, solvent are mixed under 30%-90 ℃, stirring condition and dissolve, the solution that obtains after filtration, obtain the composite bed casting solution that mass concentration is the composite polrvinyl chloride hollow fiber ultrafiltration membrane of 15%-25% after the deaeration;
Described polyvinyl chloride polymerization degree is 600-3000;
Described hydrophilic polymer is a kind of in cellulose diacetate, Triafol T, polyvinyl alcohol, vinyl chloride-vinyl acetate bipolymer, chloroethylene-vinyl acetate-maleic acid acid anhydride terpolymer, vinyl chloride-vinyl acetate-vinyl alcohol terpolymer, ethylene-vinyl acetate copolymer, the polyvinyl butyral resin;
Described pore former is a kind of in polyvinylpyrrolidone, the polyethylene glycol or both mixtures, and the polyvinylpyrrolidone model can be K12, K17, K25, K30, K60, K90, and molecular weight polyethylene glycol is 200-20000;
Described solvent is a kind of in dimethyl formamide, dimethylacetylamide, the N-methyl pyrrolidone or both mixtures;
(3) composite polrvinyl chloride hollow fiber ultrafiltration membrane moulding: with the basement membrane liquid of composite polrvinyl chloride hollow fiber ultrafiltration membrane and composite bed casting solution with 1: 100-100: 1 volume ratio, preferably 1: 20-20: 1, extrude the tubulose liquid film by the spinneret of doughnut spinning-drawing machine simultaneously with the inner gel medium, this liquid film enters film-forming in the outer setting medium through behind 0-20 centimetre the air-gap;
Described inner gel medium is that mass concentration is the 0%-30% solvent aqueous solution, 10 ℃-40 ℃ of temperature; Described extrusion temperature is 20 ℃-60 ℃; Described air-gap condition is: 10 ℃-40 ℃ of temperature, relative humidity 30%-99%RH; Described outer gel media is that mass concentration is the 0%-50% solvent aqueous solution, 10 ℃-40 ℃ of temperature;
(4) post processing: the hollow fiber ultrafiltration membrane that step (3) makes is washed immersion under 10 ℃-40 ℃ condition, promptly get the composite polrvinyl chloride hollow fiber ultrafiltration membrane to remove solvent and the part pore former in the casting solution system, to dry again.
With respect to scheme of the prior art, advantage of the present invention is:
The preparation method of composite polrvinyl chloride hollow fiber ultrafiltration membrane of the present invention has adopted composite membrane technology, can spin out stable performance, intensity height, flux is big, rejection is high, pliability is excellent composite polrvinyl chloride hollow fiber ultrafiltration membrane, by outer compound one deck hydrophilic polymers, make the composite polrvinyl chloride hollow fiber ultrafiltration membrane of different polyvinyl chloride and hydrophilic polymer layer thickness by the optimal control basement membrane liquid and the solution feed proportioning of composite bed spinning solution in hydrophobicity polyvinyl chloride hollow fiber ultrafiltration membrane.
The specific embodiment
Below in conjunction with specific embodiment such scheme is described further.Should be understood that these embodiment are used to the present invention is described and are not limited to limit the scope of the invention.The implementation condition that adopts among the embodiment can be done further adjustment according to the condition of concrete producer, and not marked implementation condition is generally the condition in the normal experiment.
The preparation of embodiment 1 composite polrvinyl chloride hollow fiber ultrafiltration membrane
With mass percent is that 10/2/88 polyvinyl chloride (degree of polymerization 3000), polyvinylpyrrolidone (K90), dimethylacetylamide system are dissolved under 40 ℃ of stirrings, and the solution after the dissolving after filtration, make composite polrvinyl chloride hollow fiber ultrafiltration membrane basement membrane liquid after the deaeration; With mass percent is that 15/3/82 cellulose diacetate, polyethylene glycol (molecular weight 1000), dimethylacetylamide system are dissolved under 60 ℃ of stirrings, and the solution after the dissolving after filtration, make cellulose diacetate composite spinning liquid after the deaeration; With polyvinyl chloride basement membrane liquid and cellulose diacetate composite spinning liquid is that 15: 1 ratios and inner gel medium (water, 10 ℃) are extruded by the spinneret of doughnut spinning-drawing machine simultaneously at 20 ℃ by volume, directly enters film-forming in 10 ℃, the outer gel media of pure water; Again film is soaked 24h in 10 ℃ pure water, take out to dry promptly getting the composite polrvinyl chloride hollow fiber ultrafiltration membrane.After measured, the flux of film is 1058.2L/m
2H, rejection is 99.8%.
The preparation of embodiment 2 composite polrvinyl chloride hollow fiber ultrafiltration membrane
With mass percent is that 25/5/70 polyvinyl chloride (degree of polymerization 600), polyethylene glycol (molecular weight 20000), dimethyl formamide system are dissolved under 80 ℃ of stirrings, and the solution after the dissolving after filtration, make composite polrvinyl chloride hollow fiber ultrafiltration membrane basement membrane liquid after the deaeration; With mass percent is that 22/4/74 polyvinyl alcohol, polyethylene glycol (molecular weight 200), dimethyl formamide system are dissolved under 50 ℃ of stirrings, and the solution after the dissolving after filtration, make polyvinyl alcohol composite spinning liquid after the deaeration; Polyvinyl chloride basement membrane liquid and polyvinyl alcohol composite spinning liquid are extruded by the spinneret of doughnut spinning-drawing machine at 30 ℃ simultaneously in 1: 12 ratio and inner gel medium (mass concentration be the 30% dimethyl formamide aqueous solution, 40 ℃), and it is film-forming in the outer gel media of the 50% dimethyl formamide aqueous solution that the liquid film of extruding enters 40 ℃, mass concentration after through 5 centimetres air-gap (40 ℃ of temperature, relative humidity 90%RH); Again film is soaked 20h in 40 ℃ pure water, take out to dry promptly getting the composite polrvinyl chloride hollow fiber ultrafiltration membrane.After measured, the flux of film is 1223.7L/m
2H, rejection is 99.0%.
The preparation of embodiment 3 composite polrvinyl chloride hollow fiber ultrafiltration membrane
With mass percent is that 16/4/80 polyvinyl chloride (degree of polymerization 2500), polyvinylpyrrolidone (K12), N-methyl pyrrolidone system are dissolved under 70 ℃ of stirrings, and the solution after the dissolving after filtration, make composite polrvinyl chloride hollow fiber ultrafiltration membrane basement membrane liquid after the deaeration; With mass percent is that 25/5/70 vinyl chloride-vinyl acetate bipolymer, polyvinylpyrrolidone (K30), N-methyl pyrrolidone system are dissolved under 80 ℃ of stirrings, and the solution after the dissolving after filtration, make vinyl chloride-vinyl acetate composite spinning liquid after the deaeration; Polyvinyl chloride basement membrane liquid and vinyl chloride-vinyl acetate composite spinning liquid are extruded by the spinneret of doughnut spinning-drawing machine at 60 ℃ simultaneously in 7: 3 ratios and inner gel medium (mass concentration be 15%N-methyl pyrrolidone, 25 ℃), and the liquid film of extruding enters film-forming in 24 ℃, the outer gel media of pure water after through 12 centimetres air-gap (10 ℃ of temperature, relative humidity 99%RH); Again film is soaked 20h in 24 ℃ pure water, take out to dry promptly getting the composite polrvinyl chloride hollow fiber ultrafiltration membrane.After measured, the flux of film is 1175.8L/m
2H, rejection is 99.2%.
The preparation of embodiment 4 composite polrvinyl chloride hollow fiber ultrafiltration membrane
With mass percent is that 20/1/2/77 polyvinyl chloride (degree of polymerization 1500), polyvinylpyrrolidone (K60), polyethylene glycol (molecular weight 600), dimethyl formamide system are dissolved under 60 ℃ of stirrings, and the solution after the dissolving after filtration, make composite polrvinyl chloride hollow fiber ultrafiltration membrane basement membrane liquid after the deaeration; With mass percent is that 25/5/70 chloroethylene-vinyl acetate-maleic acid acid anhydride terpolymer, polyethylene glycol (molecular weight 10000), dimethyl formamide system are dissolved under 80 ℃ of stirrings, and the solution after the dissolving after filtration, make chloroethylene-vinyl acetate-maleic acid acid anhydride terpolymer composite spinning liquid after the deaeration; Polyvinyl chloride basement membrane liquid and chloroethylene-vinyl acetate-maleic acid acid anhydride terpolymer composite spinning liquid are extruded by the spinneret of doughnut spinning-drawing machine at 30 ℃ simultaneously in 10: 3 ratios and inner gel medium (mass concentration be 10% dimethyl formamide, 26 ℃), and it is film-forming in the outer gel media of 20% dimethyl formamide that the liquid film of extruding enters 35 ℃, mass concentration after through 10 centimetres air-gap (30 ℃ of temperature, relative humidity 80%RH); Again film is soaked 15h in 30 ℃ pure water, take out to dry promptly getting the composite polrvinyl chloride hollow fiber ultrafiltration membrane.After measured, the flux of film is 1274.3L/m
2H, rejection is 99.8%.
The preparation of embodiment 5 composite polrvinyl chloride hollow fiber ultrafiltration membrane
With mass percent is that 22/1/3/44/30 polyvinyl chloride (degree of polymerization 1000), polyvinylpyrrolidone (K17), polyethylene glycol (molecular weight 4000), dimethyl formamide, dimethylacetylamide system are dissolved under 80 ℃ of stirrings, and the solution after the dissolving after filtration, make composite polrvinyl chloride hollow fiber ultrafiltration membrane basement membrane liquid after the deaeration; With mass percent is that 18/3/49/30 polyvinyl butyral resin, polyvinylpyrrolidone (K25), dimethyl formamide, dimethylacetylamide system are dissolved under 70 ℃ of stirrings, and the solution after the dissolving after filtration, make polyvinyl butyral resin composite spinning liquid after the deaeration; Polyvinyl chloride basement membrane liquid and polyvinyl butyral resin composite spinning liquid are extruded by the spinneret of doughnut spinning-drawing machine at 50 ℃ simultaneously in 7: 18 ratios and inner gel medium (water, 10 ℃), and it is film-forming in the outer gel media of 30% dimethyl formamide that the liquid film of extruding enters 30 ℃, mass concentration after through 20 centimetres air-gap (20 ℃ of temperature, relative humidity 30%RH); Again film is soaked 20h in 20 ℃ pure water, take out to dry promptly getting the composite polrvinyl chloride hollow fiber ultrafiltration membrane.After measured, the flux of film is 1197.6L/m
2H, rejection is 99.3%.
The preparation of embodiment 6 composite polrvinyl chloride hollow fiber ultrafiltration membrane
With mass percent is that 18/5/77 polyvinyl chloride (degree of polymerization 2000), polyethylene glycol (molecular weight 6000), dimethylacetylamide system are dissolved under 70 ℃ of stirrings, and the solution after the dissolving after filtration, make composite polrvinyl chloride hollow fiber ultrafiltration membrane basement membrane liquid after the deaeration; With mass percent is that 20/5/75 Triafol T, polyvinylpyrrolidone (K30), dimethylacetylamide system are dissolved under 80 ℃ of stirrings, and the solution after the dissolving after filtration, make Triafol T composite spinning liquid after the deaeration; Polyvinyl chloride basement membrane liquid and Triafol T composite spinning liquid are extruded by the spinneret of doughnut spinning-drawing machine at 40 ℃ simultaneously in 1: 1 ratio and inner gel medium (mass concentration be the 15% dimethylacetylamide aqueous solution, 25 ℃), and it is film-forming in the outer gel media of 40% dimethylacetylamide that the liquid film of extruding enters 40 ℃, mass concentration after through 15 centimetres air-gap (25 ℃ of temperature, relative humidity 50%RH); Again film is soaked 24h in 30 ℃ pure water, take out to dry promptly getting the composite polrvinyl chloride hollow fiber ultrafiltration membrane.After measured, the flux of film is 1074.3L/m
2H, rejection is 99.8%.
Above-mentioned example only is explanation technical conceive of the present invention and characteristics, and its purpose is to allow the people who is familiar with this technology can understand content of the present invention and enforcement according to this, can not limit protection scope of the present invention with this.All spirit essence is done according to the present invention equivalent transformation or modification all should be encompassed within protection scope of the present invention.