EP0099699A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Polymeric microfibrous filter sheet, preparation and use
Assignee: Pall Corp
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Filing: 1983-07-07
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Granted: —
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Expires: 2003-07-07
Abstract
Abstract Microfibrous, polymeric sheets and filter elements prepared therefrom comprising a normally hydrophobic, microfibrous, polymeric web, wherein the surfaces of the microfibrous making up the web are coated with a cured, precipitated cationic, thermosetting binder resin or polymer, which elements are hydrophilic and have a positive zeta potential. The corresponding process comprises (1) applying a solution of a precipitating agent to a hydrophobic web; (2) applying a binder resin to the web of step (1); (3) working the web of step (2) to mix the agent and binder, thereby facilitating the precipitation of the binder resin and the distribution of the precipitated binder resin as a coating on the surface of the microfibers of the web; and (4) curing the web of step (3) to form desired filter elements.
Inventors
- 👤 David Boris Pall
- 👤 Peter John Degen
- 👤 Thomas Charles Gsell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 11:36
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/28; C02F1/285; A; A61; A61L; A61L2/00; A61L2/02; A61L2/022; B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; B01D2239/00; B01D2239/04; B01D2239/0414; B01D2239/0421; B01D2239/0471; B01D2239/08; B01D2239/10; B01D2239/12; B01D2239/1216; B01D2239/1233; B01D2239/1291
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
160 words
A process for converting a hydrophobic web comprising polymeric microfibers to a hydrophilic filter sheet characterised by the steps of: (1) applying a first solution or dispersion of a precipitating agent to said web at least partially to wet said web, (2) applying a second solution of a water-soluble, non-colloidal, cationic, thermosetting binder resin or polymer to the wetted web of step (1) to form a web wetted with a mixture of said first and second solutions; (3) working the wetted web of step (2) to mix said first and second solutions thereby facilitating the precipitation of said binder resin or polymer and the distribution thereof as a coating on the surfaces of the microfibers; and (4) drying the coated web of step (3) and curing the precipitated resin to provide a hydrophilic, microfibrous:, polymeric filter sheet with a positive zeta potential whereof the surfaces of the microfibers are coated with a cured, precipitated, thermoset, cationic binder resin or polymer.
Claim 2
Dependent Claim
160 words
A process for converting a hydrophobic web comprising polymeric microfibers to a hydrophilic filter sheet characterised by the steps of: (1) applying a first solution or dispersion of a precipitating agent to said web at least partially to wet said web, (2) applying a second solution of a water-soluble, non-colloidal, cationic, thermosetting binder resin or polymer to the wetted web of step (1) to form a web wetted with a mixture of said first and second solutions; (3) working the wetted web of step (2) to mix said first and second solutions thereby facilitating the precipitation of said binder resin or polymer and the distribution thereof as a coating on the surfaces of the microfibers; and (4) drying the coated web of step (3) and curing the precipitated resin to provide a hydrophilic, microfibrous:, polymeric filter sheet with a positive zeta potential whereof the surfaces of the microfibers are coated with a cured, precipitated, thermoset, cationic binder resin or polymer.
Claim 3
Dependent Claim
46 words
A process according to claim 1 characterised in that said working of the wetted web of step (2) is carried out by contacting said wetted web with a roller rotating counter to the direction said wetted web is moving as the web moves past said roller.
Claim 4
Dependent Claim
46 words
A process according to claim 1 or claim 2 characterized in that said drying and said curing in step (4) are carried out at an elevated temperature of from about 50 to about 150 degrees Centigrade for a period of from several minutes to several days.
Claim 5
Dependent Claim
44 words
A process according to any one of claims 1 to 3 characterised in that said polymeric microfibers of said hydrophobic web comprise a polyolefin and said hydrophobic web is prewet with a wetting solution comprising water and a wetting agent prior to step (1).
Claim 6
Dependent Claim
29 words
A process according to any one of claims 1 to 3 characterised in that said polymeric microfibers of said hydrophobic web include, nylon 66, nylon 11, or other polyamide.
Claim 7
Dependent Claim
29 words
A process according to any one of claims 1 to 3 characterised in that said polymeric microfibers of said hydrophobic web include polyethylene terephthalate, polybutylene terephthalate or other polyester.
Claim 8
Dependent Claim
61 words
A process according to any one of claims 1 to 6 characterised in that said microfibers have diameters of from 0.5 to 20 micrometers and said hydrophobic web has absolute pore ratings of from 0.5 to 80 micrometers, preferably diameters of from 1.0 to 10 micrometers and said hydrophobic web has An absolute pore rating of from 0.6 to 10 micrometers.
Claim 9
Dependent Claim
43 words
A process according to any one of claims 1 to 7 characterised in that the concentration of said binder resin or polymer in said second solution is in the range of from 0.1 to . 20 percent of preferably 0.1 to 10 percent.
Claim 10
Dependent Claim
36 words
A process, according to any one of claims 1 to 8 characterised in that the concentration of said precipitating agent in said first solution or dispersion is in the range of from 2.5 to 7.5 percent.
Claim 11
Dependent Claim
68 words
A process according to any one of claims 1 to 9 characterised in that said second solution is applied to said wetted web of step (1) in an amount such that the total weight of said binder resin or polymer added to said wetted web of step (1) is from 1 to 30 percent preferably 5 to 15 percent based on the dry weight of said hydrophobic web.
Claim 12
Dependent Claim
53 words
A process according to any one of claims 1 to 10 characterised in that the weight ratio of said binder resin or polymer to said precipitating agent in said wetted web of step (2) just prior to said working of said wetted web is from 4:1 to 1:1, preferably from 2:1 to 1:1.
Claim 13
Dependent Claim
30 words
A process according to any one of claims 1 to 11 characterised in that said precipitating agent contains anionic groups such as carboxylate and sulfonate or other anionic precipitating agent.
Claim 14
Dependent Claim
20 words
A process according to claim 12 characterised in that the anionic precipitating agent is a water-soluble, self-catalyzed, thermosetting, acrylic resin.
Claim 15
Dependent Claim
23 words
A process according:to any one of claims 1 to 13 characterised in that the binder resin or polymer includes an epoxy- functional polyamido/polyamino-epichlorohydrin.
Claim 16
Dependent Claim
28 words
A process according to any one of claims 1 to 13 characterised in that said thermosetting binder resin or polymer includes an epoxy-functional polyamine-epichlorohydrin containing quaternary ammonium groups.
Claim 17
Dependent Claim
65 words
A process-according to any one of claims 1 to 15 characterised in that prior to applying said first solution or dispersion to said web in step (1), a mixture comprising water and a wetting agent is applied to said web to prewet said web followed by washing the prewetted web with water to remove said wetting agent while maintaining the web in a water-wetted form.
Claim 18
Dependent Claim
25 words
A process according to any one of claims 1 to 16 characterised in that the said first and second steps are carried out substantially simultaneously.
Claim 19
Dependent Claim
29 words
A process according to any one of claims 1 to 17, characterised in that the order of said steps (1) and (2) are reversed when carrying out the process,
Claim 20
Dependent Claim
46 words
A microfibrous, polymeric filter sheet characterised by a normally hydrophobic, microfibrous, polymeric web wherein the surface of the polymeric microfibers of said web are coated with a cured, precipitated, cationic, thermoset binder resin or polymer, said filter sheet being hydrophilic and having a positive zeta potential.
Claim 21
Dependent Claim
46 words
A microfibrous, polymeric filter sheet characterised by a normally hydrophobic, microfibrous, polymeric web wherein the surface of the polymeric microfibers of said web are coated with a cured, precipitated, cationic, thermoset binder resin or polymer, said filter sheet being hydrophilic and having a positive zeta potential.
Claim 22
Dependent Claim
18 words
A sheet according to claim 19 characterised in that said polymeric microfibers include, polypropylene, polyethylene or other polyolefin.
Claim 23
Dependent Claim
23 words
A sheet according to claim 19 characterised in that said polymeric microfibers of said web include nylon 66, nylon 11 or other polyamide.
Claim 24
Dependent Claim
18 words
A sheet according tp claim 19 characterised in that said polyermic microfibers of said web include polyethylene terephthalate.
Claim 25
Dependent Claim
29 words
A sheet according to any one of claims 19 to 22 characterised in that the microfibers diameters are from 0.5 to 20 micrometers, preferably from 1.0 to 10 micrometers.
Claim 26
Dependent Claim
32 words
A sheet according to any one of claims 19 to 23 characterised in that the sheet has absolute pore ratings of from 0.5 to 80 micrometers, preferably, from 0.5 to 10 micrometers.
Claim 27
Dependent Claim
41 words
A sheet according to any one of claims 19 to 24 characterised in that said resin or polmyer is present in .an amount of from 1 to 30 percent based on the dry weight of said normally hydrophobic, microfibrous, polymeric web.
Claim 28
Dependent Claim
26 words
A sheet according to any one of claims 19 to 25 characterised by positive zeta potential oyer the entire pH range of from 3 to 10.
Claim 29
Dependent Claim
27 words
A sheet according to anv one of claims 19 to 26 characterised in that said binder resin or polymer comprises an epoxy-functional polyamine-epichlorohydrin containing quaternary ammonium groups,
References Cited (Backward Citations)
No citation records indexed.
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