US3770532A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Porous bodies and method of making
Assignee: General Electric Co
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Filing: 1971-02-16
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Granted: 1973-11-06
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Expires: 1991-02-16
Abstract
Abstract A process for making tapered holes in a solid material which contains tracks of radiation damaged material is described. One surface of the solid is contacted with an etchant while the opposite surface of the solid is contacted with an agent capable of substantially stopping the etching action of the etchant. Such an agent can be a neutralizer for the etchant or an inert medium. The etchant etches, i.e., extracts, the track-defining radiation damaged material, and upon penetrating through the solid to form a hole, it contacts the neutralizer or inert medium and its etching action is substantially stopped. The product is useful as a filter.
Inventors
- 👤 C Bean
- 👤 Sorbo W De
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:35
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0023; B01D67/0032; B01D29/00; B01D29/01; B01D29/012; B01D35/00; B01D2201/00; B01D2201/18; B01D2201/184
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
30 words
A process for making tapered holes of substantially uniform size in a sheet of a non-metallic solid according to claim 1 wherein said sheet is formed from a synthetic polymer.
Claim 2
Dependent Claim
41 words
A process for making tapered holes of substantially uniform size in a sheet of a non-metallic solid according to claim 1 wherein said etchant fluid is selected from the group consisting of hydrofluoric acid, sodium hydroxide, potassium hydroxide and potassium permanganate.
Claim 3
Dependent Claim
33 words
A process for making tapered holes of substantially uniform size in a sheet of a non-metallic solid according to claim 1 wherein a pressure higher than atmospheric pressure is applied to said agent.
Claim 4
Dependent Claim
224 words
A process for making tapered holes of substantially uniform size in a solid sheet of polycarbonate ranging in thickness from about 1 to 20 microns to produce an article useful as a filter for separating molecules of different sizes which comprises bombarding a side of said sheet with fission fragments to form charged particle tracks of radiation damaged material extending through said sheet from the bombarded side through the opposite side, affixing separating means along the periphery portion of said sheet to separate the two sides of said sheet, contacting one side only of said bombarded sheet with an etchant fluid which etches and removes said tracks of damaged material, contacting the opposite side only of said sheet with a neutralizing agent prior to the formation of etched holes through said sheet by said etchant fluid, said neutralizing agent for said etchant fluid being selected from the group consisting of an inert liquid, a neutralizing liquid, and neutralizing gas, allowing said etchant fluid to etch and remove said tracks of damaged material to form holes therethrough whereupon its etching action in each just-formed hole is stopped by said agent in contact with said opposite side of said sheet, said separating means being such as to separate said etchant fluid from said neutralizing agent so that the only contact therebetween is through said etched holes.
Claim 5
Dependent Claim
143 words
A continuous process for forming small tapered holes of substantially uniform size in two flexible sheets of synthetic polymer wherein each sheet ranges in thickness from about 1 to 20 microns to produce an article useful as a filter for separating molecules of different sizes which comprises bombarding a side of each sheet with fission fragments to produce substantially straight charged particle tracks of radiation damaged material extending through each sheet from the bombarded side through the opposite side, placing an absorbent material containing a liquid neutralizer between said two sheets to form a composite, passing the composite through an etchant fluid which etches and removes said tracks of damaged material, and allowing sAid etchant fluid to etch and remove said tracks of damaged material to form holes therethrough whereupon its etching action in each just-formed hole is stopped by said liquid neutralizer.
Claim 6
Dependent Claim
14 words
A continuous process according to claim 6 wherein said synthetic polymer is a polycarbonate.
References Cited (Backward Citations)
US1642419A
Cited
US3259461A
Cited
US3131103A
Cited
US3303085A
Cited
US3243323A
Cited
US3335278A
Cited
US3343256A
Cited
US3415993A
Cited
US3472629A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |