US4879182A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of coating carbon bodies
Assignee: Ethyl Corp
•
Filing: 1988-10-24
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Granted: 1989-11-07
•
Expires: 2008-10-24
Abstract
Abstract Described is a way of sealing a carbon body such as monolithic graphite tooling so that it retains its vacuum integrity through numerous thermal cycles typical of thermoplastic processing. This is accomplished by (a) applying to the body surface a coating formulation composed of a carbon-filled solution of a polyamic acid formed by reaction between pyromellitic acid dianhydride and 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide.
Inventors
- 👤 J. Kenneth Presswood
- 👤 Alethea H. O'Quinn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:12
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/46; C04B41/48; C04B41/4838; C04B41/4842; C04B41/488; C04B41/80; C04B41/81; C04B41/82; C04B41/83; Y; Y10; Y10T; Y10T428/00; Y10T428/30; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
71 words
A method sealing monolithic carbon bodies which comprises (a) applying to a vacuum-porous carbon body a coating formulation composed of a carbon-filled solution of a polyamic acid formed by reaction between pyromellitic acid dianhydride and a 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide and thereby rendering the coated portion of the carbon body capable of holding a vacuum.
Claim 2
Independent Claim
71 words
A method sealing monolithic carbon bodies which comprises (a) applying to a vacuum-porous carbon body a coating formulation composed of a carbon-filled solution of a polyamic acid formed by reaction between pyromellitic acid dianhydride and a 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide and thereby rendering the coated portion of the carbon body capable of holding a vacuum.
Claim 3
Dependent Claim
24 words
A method of claim 1 wherein the monolithic carbon body is monolithic graphite tooling and the carbon of the carbon-filled solution is graphite powder.
Claim 4
Dependent Claim
10 words
A method of claim 1 wherein the 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane is 2,2-bis[4-(4'-aminophenoxy)henyl]hexafluoropropane.
Claim 5
Dependent Claim
21 words
A method of claim 1 wherein the coating formulation is applied to a monolithic carbon body devoid of a basecoat thereunder.
Claim 6
Dependent Claim
32 words
A method of claim 1 wherein the coating formulation is applied to a monolithic carbon body havingg a basecoat thereunder comprising a polyimide of benzophenone tetracarboxylic acid dianhydride and 2,2-bis[4-(4'-aminophenoxy)phenyl]hexafluoropropane formed thereon.
Claim 7
Dependent Claim
10 words
A method of claim 5 wherein the basecoat is carbon-filled.
Claim 8
Dependent Claim
30 words
A method of claim 1 wherein the monolithic carbon body is monolithic graphite tooling and the carbon of the carbon-filled solution is graphite powder; and wherein the 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane is 2,2-bis[4-(4'-aminophenoxy)phenyl]hexafluoropropane.
Claim 9
Dependent Claim
21 words
A method of claim 7 wherein the coating formulation is applied to the monolithic graphite body devoid of a basecoat thereunder.
Claim 10
Independent Claim
92 words
A method sealing monolithic carbon bodies which comprises (a) spraying onto a vacuum-porous carbon body a coating formulation composed of from about 15 to 30 PVC finely divided carbon dispersed in a solution containing from about 5 to about 8% by weight solids content of a polyamic acid formed by reaction between pyromellitic acid dianhydride and a 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide and thereby rendering the coated portion of the carbon body capable of holding a vacuum.
Claim 11
Independent Claim
92 words
A method sealing monolithic carbon bodies which comprises (a) spraying onto a vacuum-porous carbon body a coating formulation composed of from about 15 to 30 PVC finely divided carbon dispersed in a solution containing from about 5 to about 8% by weight solids content of a polyamic acid formed by reaction between pyromellitic acid dianhydride and a 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide and thereby rendering the coated portion of the carbon body capable of holding a vacuum.
Claim 12
Dependent Claim
30 words
A method of claim 9 wherein the monolithic carbon body is monolithic graphite tooling and the carbon of the carbon-filled solution is graphite powder; and wherein the 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane is 2,2-bis[4-(4'-aminophenoxy)phenyl]hexafluoropropane.
Claim 13
Dependent Claim
21 words
A method of claim 9 wherein the coating formulation is applied to the monolithic graphite body devoid of a basecoat thereunder.
Claim 14
Dependent Claim
72 words
A method of claim 9 wherein the monolithic carbon body is monolithic graphite tooling and the carbon of the carbon-filled solution is graphite powder; wherein the 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane is 2,2-bis[4-(4'-aminophenoxy)phenyl]hexafluoropropane; wherein the solvent of the coating formulation comprises a dipolar aprotic solvent and a lower dialkyl ketone; wherein the coating formulation is applied to the monolithic graphite body devoid of a basecoat thereunder; and wherein the curing is conducted with staged increasing temperatures.
Claim 15
Dependent Claim
75 words
A normally vacuum porous carbon body having thereon a coating formed by (a) applying to a surface thereof a coating formulation composed of a carbon-filled solution of a polyamic acid formed by reaction between (a) pyromellitic acid dianhydride and a 2,2-bis-[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide and thereby rendering the coated portion of the carbon body capable of holding a vacuum.
Claim 16
Dependent Claim
75 words
A normally vacuum porous carbon body having thereon a coating formed by (a) applying to a surface thereof a coating formulation composed of a carbon-filled solution of a polyamic acid formed by reaction between (a) pyromellitic acid dianhydride and a 2,2-bis-[4-(aminophenoxy)phenyl]hexafluoropropane, and (b) heat curing the coated body to cause the polyamic acid to imidize into a thermally cured polyimide and thereby rendering the coated portion of the carbon body capable of holding a vacuum.
Claim 17
Dependent Claim
24 words
An article of claim 13 wherein the monolithic carbon body is monolithic graphite tooling and the carbon of the carbon-filled solution is graphite powder.
Claim 18
Dependent Claim
19 words
An article of claim 14 wherein the coating on the monolithic graphite body is devoid of a basecoat thereunder.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-06 | 1993-05-08 | 1993-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-06 | 1997-05-08 | 1997-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-06 | 2001-05-08 | 2001-11-07 | $7700.00 | Window Closed / Lapsed |