Coating processes – Foraminous product produced – Microporous coating
Patent
1997-05-30
1999-06-22
Dudash, Diana
Coating processes
Foraminous product produced
Microporous coating
427235, 427238, 427244, 427378, 427379, 427381, B05D 722, B05D 500
Patent
active
059141549
ABSTRACT:
A process for placing an ultra thin layer of a non-porous gas permeable polymer continuously over an entire filter surface area allows the fabrication of compact, high flux, fouling resistant gas filters. The process involves contacting a dilute coating solution of gas permeable polymer in a solvent with one side of a microporous substrate. The pore size of the substrate is chosen for its ability to effectively filter the gas permeable polymer from the coating solution. Solvent of the coating solution is made to flow through the microporous substrate which causes an ultra thin layer of polymer to build up on the side of substrate. When a desired thickness of polymer is built up, the solution and solvent is removed and residual solvent is evaporated, preferably by passing a gas at high rate over the surface of the polymer layer.
This process can be used to coat flat sheet and hollow fiber substrates. The process is particularly useful for coating multiple hollow fibers assembled in modules which by virtue of the high surface area density of small diameter fibers and the efficient packing of many fibers in the modules, provide very high filter surface area in a small volume. The coated fiber modules thus can be used as high flow rate gas filters in applications such as filtering nuisance particules from recovered gas streams, collecting hazardous or valuable droplets suspended in a gas process stream for protection or salvage. Specific applications include filtering air for microelectronic circuit assembly facilities and filtering microbes from the atmosphere in biomedical "clean rooms".
A preferred gas permeable polymer for use with this invention is an amorphous copolymer of perfluoro-2,2-dimethyl-1,3-dioxole. The superior hydrophobicity and oleophobicity of this material in the form of a non-porous, continuous layer provides a barrier for solid particles and liquid droplets from blocking flow through a gas filter. Furthermore, a gas filter made according to this invention can be easily cleaned and restored to near-original gas flux performance.
REFERENCES:
patent: 3661621 (1972-05-01), Jager
patent: 4214020 (1980-07-01), Ward et al.
patent: 4230463 (1980-10-01), Henis et al.
patent: 4243701 (1981-01-01), Riley et al.
patent: 4347204 (1982-08-01), Takagi et al.
patent: 4767643 (1988-08-01), Westervelt et al.
patent: 4778477 (1988-10-01), Lauchenauer
patent: 4840819 (1989-06-01), Williams et al.
patent: 4844871 (1989-07-01), Polaschegg
patent: 4857080 (1989-08-01), Baker et al.
patent: 4938778 (1990-07-01), Ohyabu et al.
patent: 5051114 (1991-09-01), Nemser et al.
patent: 5116650 (1992-05-01), Bowser
patent: 5238471 (1993-08-01), Blanchet-Fincher
patent: 5258202 (1993-11-01), Pellegrino et al.
patent: 5523118 (1996-06-01), Williams
patent: 5554414 (1996-09-01), Moya et al.
Lund, L. W., et al., Gas permeability of hollow fiber membranes in a gas-liquid system, Journal of Membrane Science, 117 (1996) 207-219. (no month).
Nemser, S., Applications of Membranes in Industry Glassy Fluoropolymer Membranes, 21st Aharon Katzir-Katchalsky Conference, Rehovot, Israel, Sep. 5-8, 1993.
Nemser, S., "Graph I" presentation at University of Pittsburgh, Pittsburgh, Pennsylvania, Feb. 27, 1996.
"The Filtration Spectrum" Osmonics Inc., 5951 Clearwater Drive, Minnetonka MN, 1984 (no month).
Yeung, K.L., et al. Novel Preparation Techniques for Thin Metal-Ceramic Composite Membranes, AIChE Journal, vol. 41, No. 9, Sep., 1995.
Pinnau et al: J. Membrane Sci., vol. 109, pp. 125-133, 1996. no month.
Compact Membrane Systems, Inc.
Dudash Diana
Lew Jeffrey C.
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