US4971697A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin silica flakes and method of making
Assignee: 3M Co
•
Filing: 1989-02-23
•
Granted: 1990-11-20
•
Expires: 2009-02-23
Abstract
Abstract Hydrated sodium silicate particles can be expanded by heat to form thin-walled bubbles that can be broken, neutralized, washed and dried to provide hydrated silica flakes. These flakes can be mixed with non-swelling sorptive particles such as TLC grade silica and used to make chromatographic articles. One such article is a composite of a poly(tetrafluoroethylene) fibril matrix in which those particles and hydrated or fired silica flakes are enmeshed. The hydrated silica flakes can be fired to a refractory state and then incorporated into protective coatings to enhance their resistance to abrasion while also better protecting the coated substrates from corrosion.
Inventors
- 👤 David K. Douden
- 👤 Thomas J. Scanlan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:09
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/2803; B01J20/02; B01J20/10; B01J20/103; B01J20/28002; B01J20/28004; B01J20/28028; B01J20/281; B01J20/291; C01B33/14; C01B33/152; C09; C09D; C09D7/00; C09D7/40; C09D7/60; C09D7/61; C09D7/70; B01J2220/00; B01J2220/50; B01J2220/54; C08; C08K; C08K3/00; C08K3/34; C08K3/36; Y; Y10; Y10S; Y10S435/00; Y10S435/803; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249954; Y10T428/249962; Y10T428/249964; Y10T428/249986
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
40 words
A composite chromatographic article comprising a carrier bearing a mixture of non-swellable sorptive particles and silica flakes, said silica flakes being hydrated and of substantially uniform thickness, the average thickness being greater than 0 and no more than 3.0 um.
Claim 2
Dependent Claim
40 words
A composite chromatographic article comprising a carrier bearing a mixture of non-swellable sorptive particles and silica flakes, said silica flakes being hydrated and of substantially uniform thickness, the average thickness being greater than 0 and no more than 3.0 um.
Claim 3
Dependent Claim
15 words
The composite chromatographic articles as defined in claim 1 wherein said sorptive particles comprise silica.
Claim 4
Dependent Claim
25 words
The composite chromatographic article as defined in claim 2 wherein said silica flakes comprise from 10 to 40% by weight of total particulate and flakes.
Claim 5
Dependent Claim
28 words
The composite chromatographic article as defined in claim 1 wherein said carrier is a poly(tetrafluoroethylene) fibril matrix in which said silica flakes and non-swellable sorptive particles are enmeshed.
Claim 6
Dependent Claim
12 words
The composite chromatographic article of claim 1 wherein the carrier is glass.
Claim 7
Dependent Claim
23 words
The composite chromatographic article of claim 1 wherein the carrier is selected from the group consisting of paper, metal and organic polymeric material.
Claim 8
Dependent Claim
34 words
The composite chromatographic article according to claim 1 wherein said carrier is coated on at least one surface with a layer comprising a binder and a mixture of non-swellable sorptive particulate and silica flakes.
Claim 9
Dependent Claim
27 words
The composite chromatographic article as defined in claim 1 wherein said hydrated silica flakes comprise from 10 to 40% by weight of said particulate and flakes mixture.
Claim 10
Dependent Claim
30 words
The composite chromatographic article as defined in claim 8 wherein the ratio of said particulate and flakes mixture to poly(tetrafluoroethylene) is in the range of 19:1 to 4:1 by weight.
Claim 11
Dependent Claim
28 words
The composite chromatographic article as defined in claim 9 wherein said composite article has a net surface energy in the range of 20 to 300 milliNewtons per meter.
References Cited (Backward Citations)
US3795524A
Cited
US3796777A
Cited
US3794503A
Cited
US3960583A
Cited
US4349456A
Cited
US4153661A
Cited
US4373519A
Cited
US4460642A
Cited
US4565663A
Cited
EP0240952A2
Cited
US4810381A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-11-19 | 1994-05-21 | 1994-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-19 | 1998-05-21 | 1998-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-19 | 2002-05-21 | 2002-11-20 | $7700.00 | Window Closed / Lapsed |