Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
  • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
  • D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by electro-spinning
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
  • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
  • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4282—Addition polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4382—Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
  • B01D2239/025—Types of fibres, filaments or particles, self-supporting or supported materials comprising nanofibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/0604—Arrangement of the fibres in the filtering material
  • B01D2239/0631—Electro-spun
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1233—Fibre diameter
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/20—Heavy metals or heavy metal compounds

Definitions

• This invention relates generally to sulfonated polystyrene nonwovens and a method for their preparation.
• the present invention is directed to a sulfonated polystyrene nonwoven having an average diameter from 450 nm to 2000 nm and a capacity from 0.05 meq/g to 2.0 meq/g.
• the polystyrene used to make the fibers is a high heat crystalline polystyrene, preferably one that is acceptable in pharmaceutical processing.
• the average diameter of the fibers is at least 480 nm, preferably at least 500 nm, preferably at least 520 nm; preferably no greater than 1750 nm, preferably no greater than 1500 nm, preferably no greater than 1200 nm, preferably no greater than 1000 nm, preferably no greater than 800 nm, preferably no greater than 750 nm, preferably no greater than 700 nm.
• the fibers are produced by Hybrid Membrane Technology (HMT). This technology is described, e.g., in US7618579.
• HMT Hybrid Membrane Technology
• fibers are made from a solution of polystyrene in an aprotic solvent.
• Preferred solvents are those capable of dissolving polystyrene at room temperature, and include, e.g., N,N-dimethylformamide (DMF), dimethylacetamide, methyl ethyl ketone, dichloromethane and toluene.
• the solution is processed via electroblowing under conditions which may be adjusted by known techniques to vary fiber properties, producing a nonwoven fiber mat.
• the concentration of polystyrene in the solvent is from 15 to 30 wt%, preferably 18 to 27 wt%.
• the solution is processed on a single hole or multi-hole electro-blowing unit.
• the fiber is spun onto a rotating drum.
• the fibers are treated with a crosslinking agent capable of crosslinking polystyrene prior to sulfonation.
• crosslinking agents are aldehydes and dialdehydes, preferably formaldehyde/sulfuric acid or glutaraldehyde/sulfuric acid, preferably formaldehyde/sulfuric acid.
• at least 90 wt% of the polystyrene molecules contain crosslinks, preferably at least 94 wt%, preferably at least 96 wt%, preferably at least 98 wt%.
• the wt% of polystyrene molecules that are crosslinked may be determined by immersing the fibers in dichloroethane and weighing the insoluble material, which is the polystyrene molecules containing crosslinks.
• fibers are treated with crosslinking agent at a temperature from 20 to 110°C, preferably at least 45°C, preferably at least 55°C; preferably no more than 100°C, preferably no more than 95°C. Both time and temperature may be adjusted to produce the desired degree of crosslinking, however typical times preferably are in the range from 30 minutes to 6 hours, preferably 1 to 4 hours.
• treatment with a crosslinking agent is done without a catalyst under the conditions given above. If a catalyst is used (e.g., Ag2SC>4), times will be much shorter at a given temperature and can be adjusted to provide desired properties.
• the fibers resulting from treatment with a crosslinking agent are sulfonated by contacting them with a sulfonating agent, preferably at least 80 wt% (remainder at least 95 wt% water), preferably at least 90 wt%, preferably at least 94 wt%.
• Sulfonating agents are reagents capable of sulfonating aromatic rings.
• Preferred sulfonating agents include sulfuric acid, chlorosulfonic acid and oleum; preferably sulfuric acid.
• sulfonation is performed at a temperature from 30 to 160°C, preferably at least 50°C, preferably at least 70°C; preferably no more than 120°C, preferably no more than 110°C. Both time and temperature may be adjusted to produce the desired capacity, however typical times preferably are in the range from 30 minutes to 6 hours, preferably 1 to 4 hours.
• fibers are contacted with concentrated sulfuric acid for a time sufficient to produce sulfonated polystyrene fibers having a capacity from 0.4 meq/g to 2.0 meq/g or in any desired range therein contained.
• sulfonation is done without a catalyst under the conditions given above. If a catalyst is used (e.g., Ag2SC>4, acetic anhydride, trifluoroacetic anhydride), time will be much shorter at a given temperature and can be adjusted to provide desired properties
• capacity of the sulfonated nonwoven is at least 0.2 meq/g, preferably at least 0.4 meq/g, preferably at least 0.45 meq/g, preferably at least 0.50 meq/g, preferably at least 0.55 meq/g, preferably at least 0.60 meq/g, preferably at least 0.65 meq/g; preferably no greater than 1.8 meq/g, preferably no greater than 1.6 meq/g, preferably no greater than 1.5 meq/g, preferably no greater than 1.4 meq/g, preferably no greater than 1.3 meq/g, preferably no greater than 1.2 meq/g, preferably no greater than 1.1 meq/g.
• C e.g., 30 C
• PS solutions were prepared using PS 685 D grade polystyrene obtained from Aldrich.
• the solvent was dimethylformamide (DMF). Solutions with concentrations in the range of 21 to 25 wt% were scouted. Sample solutions were spun on a single hole electro-blowing unit. The fiber was spun onto a rotating drum and the sample non-woven was collected from the drum after the run. Typical samples were prepared from a 21 wt% solution with 0.1 wt% salt added based on solution.
• the typical basis weight varied from 60 to 100 gsm. Typical distance between the spin pack and the drum collector was 33 cm.
• the typical applied voltage was 100 kV.
• the typical spin cell temperature was 30 C.
• the typical sample mean flow pour was 1 micron.
• the nanofiber membrane (1700 nm average fiber diameter) is immersed into a bath containing a mixture of reagent grade concentrated sulfuric acid and formalin (37 wt% formaldehyde), typically 90: 10 sulfuric acid : formalin (V/V).
• the bath is typically heated to 70 C for 3h and gently shaken on an orbital shaker at 60 -120 rpm.
• the bath is cooled to ⁇ 50 C, the reaction fluid is decanted, and membrane is slowly hydrated with 50% sulfuric acid, and the membrane is gradually diluted down to pure DI water.
• the nanofiber membrane after treatment with sulfuric acid/formalin is immersed in concentrated sulfuric acid (typically 96%), and then heated to 90 C for 0 to 8 h while shaking on an orbital. Next, the bath is cooled to ⁇ 50C, the reaction fluid is decanted, and the membrane is slowly hydrated with 50% sulfuric acid, and then gradually diluted down to pure DI water.
• concentrated sulfuric acid typically 96%
• volumetric Flow rate 6.9 ml/min for membrane, 5 ml/min for ion exchange resin.
• Metal content of the nonwoven PS membrane is reduced to 9.76 ppb in 210 minutes, at which time the resin still had a metal content of 20.26ppb. .
• the media is further rinsed with DI water to at least pH>5.
• Total metal content in the initial resin bed effluent was 512.7 ppb and total metal in the membrane disk effluent was 823.4 ppb.
• the membrane disk removes 96% of the initial metals at the first residence time of 3.5 seconds while ion exchange resin removes 94% of the initial metals at the first residence time of 15 min.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Nonwoven Fabrics (AREA)
• Artificial Filaments (AREA)

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• 2021
  • 2021-05-03 JP JP2022568370A patent/JP2023526197A/ja active Pending
  • 2021-05-03 KR KR1020227042286A patent/KR20230041959A/ko active Search and Examination
  • 2021-05-03 WO PCT/US2021/030406 patent/WO2021231114A1/en unknown
  • 2021-05-03 EP EP21726819.2A patent/EP4150143A1/en active Pending
  • 2021-05-03 CN CN202180038094.XA patent/CN115702268A/zh active Pending

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