US3792987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making an improved porous glass support material
Assignee: Individual
•
Filing: 1972-03-27
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Granted: 1974-02-19
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Expires: 1992-03-27
Abstract
Abstract Porous glass support materials having two essentially distinct zones of porosity. An outer surface zone comprises an outer shell with relatively large pores of controlled diameter while an inner zone comprises a core portion having relatively smaller pores of controlled diameter. The materials are made by subjecting porous glass bodies of substantially uniform pore size to a carefully controlled alkali etching cycle in which only the outer zone of the bodies have their pores enlarged. The thus treated bodies are particularly useful as chromatographic support materials which, in use, demonstrate a desirably low height equivalent theoretical plate (HETP).
Inventors
- 👤 D Eaton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:31
CPC Classifications
C; C03; C03C; C03C11/00; C03C11/005; B; B01; B01J; B01J20/00; B01J20/02; B01J20/10; B01J20/103; B01J20/28; B01J20/28002; B01J20/28004; B01J20/28054; B01J20/28078; B01J20/281; B01J20/282; B01J20/283; B01J20/30; B01J20/3071; B01J20/3078; C03C15/00; B01J2220/00; B01J2220/50; B01J2220/54
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
52 words
The method, as claimed in claim 1, wherein the porous glass body which is contacted with the alkali solution has a size between 120 and 200 mesh, U.S. Standard Sieve, the alkali solution is 1 N NaOH, and the period of contact with the alkali solution is about one to five minutes.
Claim 2
Dependent Claim
82 words
The method, as claimed in claim 1, wherein the glass formed is a sodium borosilicate glass which, after contact with the acid solution, has an average pore diameter between 20A and 60A and which, after contact with the alkali solution, consists of two distinct zones of porosity, an inner zone having an average pore diameter of between 20A and 60A, and an outer zone of enlarged pores having an average pore diameter larger than the average pore diameter of the inner zone.
Claim 3
Dependent Claim
47 words
The method, as claimed in claim 1, wherein the glass body, after contact with the acid solution, is contacted with the alkali solution for a period of time sufficient to enlarge the pores to a depth of about 10 to 50 percent of the average body radius.
Claim 4
Dependent Claim
41 words
The method, as claimed in claim 4, wherein the glass body is contacted with the alkali solution for a period of time sufficient to enlarge the pores to a depth of about 10 to 25 percent of the average body radius.
Claim 5
Dependent Claim
63 words
The method, as claimed in claim 1, wherein the glass body is a particle having a particle size between 120 and 200 mesh, U.S. Standard Sieve, the alkali solution is 1 N NaOH, and the contact with the alkali solution is for a time sufficient to enlarge the pores to a depth of about 10 to 25 percent of the average body radius.
Claim 6
Dependent Claim
49 words
The method, as claimed in claim 1, wherein the glass is a sodium borosilicate glass particle having a particle size between about 120 and 200 mesh, U.S. Standard Sieve, the alkali solution is 1 N NaOH, and the period of contact with the alkali solution is about one minute.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-18 | 1977-08-20 | 1978-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-18 | 1981-08-20 | 1982-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-18 | 1985-08-20 | 1986-02-19 | $7700.00 | Window Closed / Lapsed |