Method for preparing thin fiber-structured polymer web

• US 20020100725A1
• Filed: 12/14/2001
• Published: 08/01/2002
• Est. Priority Date: 01/26/2001
• Status: Abandoned Application

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Choi, Sung Won, Jo, Seong Mu, Chun, Suk Won, Lee, Wha Seop
• Application Number:
  US10/014,550
• Publication Number:
  US 20020100725A1
• Time in Patent Office: Days
• US Class Current: 210/503
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: D01D 5/0038 the fibre formed by solvent evaporation, i.e. dry electro-spinning
• CPC Class Codes: D01D 5/0084 Coating by electro-spinning, i.e. the electro-spun fibres are not removed from the collecting device but remain integral with it, e.g. coating of prostheses
• CPC Class Codes: D04H 1/4242 Carbon fibres
• CPC Class Codes: D04H 1/4282 Addition polymers
• CPC Class Codes: D04H 1/4326 Condensation or reaction polymers
• CPC Class Codes: D04H 1/43838 Ultrafine fibres, e.g. microfibres
• CPC Class Codes: D04H 1/728 by electro-spinning electro-spinning methods and apparatus D01D5/0007
• CPC Class Codes: Y10T 428/24 Structurally defined web or sheet [e.g., overall dimension, etc.]

Abstract

Disclosed is a method for preparing a thin fiber-structured polymer web suitable for a high-speed and large-scale production using electrospinning.

The method uses an electrospinning process to spin a solution containing a polymer in a volatile solvent to obtain a thin fiber-structured polymer web on a collector, in which case the temperature of the polymer solution is in the range of from 40° C. to the boiling point of the solvent. The porous, thin fiber-structured polymer web thus obtained is applicable to the isolation layer or the electrolytic layer for lithium-ion secondary battery, lithium-metal secondary battery or sulfur-based secondary battery, the isolation layer for fuel cells, filter, and so forth.

Claims

1. A method for preparing a thin fiber-structured polymer web, comprising the steps of:

dissolving a polymer in a volatile solvent used as a polymer solvent to prepare a polymer solution;

spinning the polymer solution by electrospinning; and

forming a thin fiber-structured polymer web cumulated on a collector.

2. The method as claimed in claim 1, wherein the volatile solvent is at least one having a high volatility selected from the group consisting of acetone, chloroform, ethanol, isopropanol, methanol, toluene, tetrahydrofuran, water, benzene, benzyl alcohol, 1,4-dioxane, propanol, carbon tetrachloride, cyclohexane, cyclohexanone, methylene chloride, phenol, pyridine, trichloroethane and acetic acid.

3. The method as claimed in claim 1, wherein the volatile solvent is a mixed solvent comprising at least one relatively high-volatility solvent and at least one relatively low-volatility solvent, the relatively high-volatility solvent being selected from the group consisting of acetone, chloroform, ethanol, isopropanol, methanol, toluene, tetrahydrofuran, water, benzene, benzyl alcohol, 1,4-dioxane, propanol, carbon tetrachloride, cyclohexane, cyclohexanone, methylene chloride, phenol, pyridine, trichloroethane and acetic acid, the relatively low-volatile solvent being selected from the group consisting of N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), 1-methyl-2-pyrrolidone (NMP), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), acetonitrile (AN), N-methylmorpholine-N-oxide, butylene carbonate (BC), 1,4-butyrolactone (BL), diethyl carbonate (DEC), diethylether (DEE), 1,2-dimethoxyethane (DME), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dioxolane (DOL), ethyl methyl carbonate (EMC), methyl formate (MF), 3-methyloxazolidin-2-on (MO), methyl propionate (MP), 2-methyletetrahydrofurane (MeTHF) and sulpholane (SL).

4. The method as claimed in claim 1, wherein the relative humidity in a working space for the electrospinning is 0 to 40%.

5. The method as claimed in claim 1, wherein the temperature of the polymer solution during the electrospinning is in the range from 40°

C. to the boiling point of the solvent.

6. The method as claimed in claim 1, wherein the content of the polymer used in the preparation of the polymer solution is 0.1 to 40 wt. % based on the content of the solvent.

7. The method as claimed in claim 1, wherein the polymer is selected from the group consisting of poly(vinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, poly(acrylonitrile-co-methacrylate), polymethylmethacrylate, polyvinylchloride, poly(vinylidenechloride-co-acrylate), polyethylene, polypropylene, nylon12, nylon-4,6, aramid, polybenzimidazole, polyvinylalcohol, cellulose, cellulose acetate, cellulose acetate butylate, polyvinyl pyrrolidone-vinyl acetates, poly(bis-(2-(2-methoxy-ethoxyethoxy))phosphazene) (MEEP), poly(propyleneoxide), poly(ethylene imide) (PEI), poly(ethylene succinate), polyaniline, poly(ethylene sulphide), poly(oxymethylene-oligo-oxyethylene), SBS copolymer, poly(hydroxy butyrate), poly(vinyl acetate), poly(ethylene terephthalate), poly(ethylene oxide), collagen, poly(lactic acid), poly(glycolic acid), poly(D,L-lactic-co-glycolic acid), polyarylates, poly(propylene fumalates), poly(caprolactone), biopolymer, coal-tar pitch, petroleum pitch, or copolymer of them, or blend of more than two of them.

8. The method as claimed in claim 7, wherein the polymer is mixed with an emulsion, or an organic or inorganic powder.

9. The method as claimed in claim 1, wherein the collector is an anode comprising at least one selected from the group consisting of LiCoO₂, LiMn₂O₂, LiMn₂O₄, LiNiO₂, LiCrO₂, LiVO₂, LiFeO₂, LiTiO₂, LiScO₂, LiYO₂, LiNiVO₄ LiNiCoO₂, V₂O₅ and V₆O₁₃;

or a cathode comprising at least one selected from the group consisting of a carbon material including graphite, cokes or hard carbon, tin oxide, lithium compound of these materials, metal lithium and metal lithium alloy.

10. The method as claimed in claim 1, wherein the collector has its upper part provided with a filtering medium.

11. The method as claimed in claim 1, further comprising the step of compulsorily discharging air containing a large amount of the solvent to the outside while injecting air into the working space during the electrospinning.

12. A thin fiber-structured polymer web obtained by the method according to claim 1.

13. A filter obtained by laminating the thin fiber-structured polymer web manufactured by the method according to claim 1.