US4624811A
Expired / Lapsed
US
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Process for preparing a vitreous carbon
Assignee: Plastics Engineering Co
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Filing: 1985-10-01
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Granted: 1986-11-25
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Expires: 2005-10-01
Abstract
Abstract The process for producing a vitreous carbon involves the molded product of a moldable composition produced from co-reacted mixtures of powder or otherwise blendable form of 20-80% by weight of a phenolic-furfuraldehyde Novolac resin and of 20-80% by weight of phenolic-aldehyde resol resin dispersed in water, either in solution or suspension, the percentages being based on the combined weight of the Novolac and resol resins, and the aldehyde in said Novolac resin comprising at least 50 molar percent, preferably substantially 100 percent, furfuraldehyde. The composition advantageously contains an amine such as hexamethylenetetramine ("hexa") in an amount equivalent to 1-15%, preferably 2-10% of hexamethylenetetramine based on the total amount of phenolic component. The composition is made by adding the preformed phenol-furfuraldehyde Novolac to the resol resin prior to dehydration of the resol resin to produce a grafted polymerization product of improved properties. The composition is particularly useful in admixture with a carbonaceous filler, preferably graphite in a proportion as high as 76% by weight based on the total composition. Generally in such admixtures the graphite may comprise 30-76%, advantageously 35-65% and preferably 40-60% of the molding composition. The vitreous carbon is improved in electrical properties and in the capability of being suitably molded, carbonized and graphitized into large shapes, particularly thin plates which are much more stress-free and crack or pore-free than otherwise produced.
Inventors
- 👤 Phillip A. Waitkus
- 👤 Louis L. Korb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:57
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/52; C04B35/528; C04B35/532; C04B35/524; C08; C08G; C08G8/00; C08G8/04; C08G8/08; C08G8/38
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
300 words
A process for preparing a vitreous carbon of improved freedom from pits and holes and much less subject to cracking and failure during formation and use, comprising the steps of: (1) molding a moldable composition of improved mold flow properties prepared by the addition of a phenolic-aldehyde Novolac resin in which at least 50 molar percent of said aldehyde is furfuraldehyde to an aqueous solution or suspension of a phenolic-aldehyde resol resin prior to the removal of 90 percent of the removable water from said resol resin solution or suspension, the proportions of said resins comprising 20-80 parts by weight of said Novolac resin and 20-80 parts by weight of said resol resin with the combined weight of said two resins comprising 100 parts by weight, thereafter effecting coreaction of said resins together with an amine selected from the group consisting of hexamethylenetetramine and amines in which there is at least one hydrogen connected to a nitrogen atom, the amount of said amine being equivalent to 1-15 percent by weight of hexamethylenetetramine based on the total weight of phenolic component, and removal of water from the resulting reaction mass while maintaining the resin in a moldable condition, the Novolac resin having been prepared with the removal of at least 25 percent by weight of the water removable during the Novolac preparation, and prior to said molding intimately mixing said coreacted resins with 5-76 percent by weight of a finely divided carbonaceous filler based on total molding composition, said molding being effected at a temperature of 100°-180° C. and a pressure between 500 pounds per square inch and 8 tons per square inch; and (2) heating the resultant molded product gradually up to a final temperature of at least 1800° and holding at said final temperature for at least 24 hours.
Claim 2
Dependent Claim
300 words
A process for preparing a vitreous carbon of improved freedom from pits and holes and much less subject to cracking and failure during formation and use, comprising the steps of: (1) molding a moldable composition of improved mold flow properties prepared by the addition of a phenolic-aldehyde Novolac resin in which at least 50 molar percent of said aldehyde is furfuraldehyde to an aqueous solution or suspension of a phenolic-aldehyde resol resin prior to the removal of 90 percent of the removable water from said resol resin solution or suspension, the proportions of said resins comprising 20-80 parts by weight of said Novolac resin and 20-80 parts by weight of said resol resin with the combined weight of said two resins comprising 100 parts by weight, thereafter effecting coreaction of said resins together with an amine selected from the group consisting of hexamethylenetetramine and amines in which there is at least one hydrogen connected to a nitrogen atom, the amount of said amine being equivalent to 1-15 percent by weight of hexamethylenetetramine based on the total weight of phenolic component, and removal of water from the resulting reaction mass while maintaining the resin in a moldable condition, the Novolac resin having been prepared with the removal of at least 25 percent by weight of the water removable during the Novolac preparation, and prior to said molding intimately mixing said coreacted resins with 5-76 percent by weight of a finely divided carbonaceous filler based on total molding composition, said molding being effected at a temperature of 100°-180° C. and a pressure between 500 pounds per square inch and 8 tons per square inch; and (2) heating the resultant molded product gradually up to a final temperature of at least 1800° and holding at said final temperature for at least 24 hours.
Claim 3
Dependent Claim
25 words
The process of claim 1 in which said amine is hexamethylenetetramine and the carbonaceous filler is 35-65 percent by weight of the total moldable composition.
Claim 4
Dependent Claim
30 words
The process of claim 1 in which the amount of said amine is equivalent to 2-8 parts by weight of hexamethylenetetramine per 100 parts by weight of said Novolac resin.
Claim 5
Dependent Claim
11 words
The process of claim 3 in which said amine is hexamethylenetetramine.
Claim 6
Dependent Claim
15 words
The process of claim 2 in which the phenolic component in the Novolac is phenol.
Claim 7
Dependent Claim
23 words
The process of claim 5 in which the phenolic component in the resol is phenol and the aldehyde in the resol is formaldehyde.
Claim 8
Dependent Claim
23 words
The process of claim 6 in which the furfuraldehyde content in said Novolac is at least 75 molar percent of the aldehyde component.
Claim 9
Dependent Claim
21 words
The process of claim 6 in which the furfuraldehyde in said Novolac is approximately 100 molar percent of the aldehyde component.
Claim 10
Dependent Claim
36 words
The process of any one of claims 1, 2, 3, 4, 5, 6, 7 or 8 in which said Novolac addition is performed after sufficient refluxing is effected for substantially complete reaction of the resol aldehyde.
Claim 11
Dependent Claim
24 words
The process of claim 8 in which said Novolac is added prior to initiation of said water removal from said resin solution or suspension.
Claim 12
Dependent Claim
27 words
The process of claim 8 in which said Novolac is added prior to removal of 25 percent of the water in said resol resin solution or suspension.
Claim 13
Dependent Claim
19 words
The process of claim 8 in which said Novolac is substantially completely free of water prior to said addition.
Claim 14
Dependent Claim
28 words
The process of claim 8 in which at least 35 percent by weight of the water initially present in said Novolac preparation is removed prior to said addition.
Claim 15
Dependent Claim
28 words
The process of claim 2 in which the carbonaceous filler is finely divided graphite and said moldable composition contains 35-65 percent by weight of said finely divided graphite.
Claim 16
Dependent Claim
28 words
The process of claim 8 in which the carbonaceous filler is finely divided graphite and said moldable composition contains 35-65 percent by weight of said finely divided graphite.
Claim 17
Dependent Claim
28 words
The process of claim 12 in which the carbonaceous filler is finely divided graphite and said moldable composition contains 35-65 percent by weight of said finely divided graphite.
Claim 18
Dependent Claim
19 words
The process of claim 4 in which said molded product is a plate having a thickness of 0.04-0.05 inch.
Claim 19
Dependent Claim
22 words
The process of claim 17 in which said molding is effected at a pressure of 800 to 1500 pounds per square inch.
Claim 20
Dependent Claim
32 words
The process of claim 18 in which the ratio of parts by weight of said resol resin to parts by weight of said Novolac is in the range of 70/30 to 50/50.
Claim 21
Dependent Claim
15 words
The process of claim 19 in which said final temperature is at least 2000° F.
Claim 22
Dependent Claim
15 words
The process of claim 19 in which said final temperature is at least 3000° F.
Claim 23
Dependent Claim
78 words
The process of claim 19 in which said resultant molded product is heated gradually up to a temperature of 600°-700° F. with the temperature increased at a rate of 105° F. per hour, then above the range of 600°-700° F. at an increasing rate of 10°-15° F. per hour up to 800°-850° F. and thereafter at 20°-25° F. per hour up to a final temperature of 1800°-3000° F., which final temperature is held for at least 24 hours.
Claim 24
Dependent Claim
32 words
The process of any of claims 1, 2, 3, 4, 5, 6, 7, 11, 13 or 15 in which said molding is effected at a pressure of 800-1500 pounds per square inch.
Claim 25
Dependent Claim
28 words
The process of claim 15 in which said hexamethylenetetramine is used in a proportion of 1 to 5 percent by weight based on the weight of resin product.
Claim 26
Dependent Claim
30 words
The process of claim 14 in which said Novolac resin is added prior to the removal of 50 percent of the removable water from said resol resin solution or suspension.
Claim 27
Dependent Claim
33 words
The process of claim 25 in which said amine is hexamethylenetetramine, the phenol component in both said Novolac and said resol resins is phenol and the aldehyde in said resol resin is formaldehyde.
Claim 28
Dependent Claim
19 words
The process of claim 26 in which the furfuraldehyde is at least 75 molar percent of the aldehyde component.
Claim 29
Dependent Claim
30 words
The process of claim 14 in which said Novolac resin is added prior to the removal of 75 percent of the removable water from said resol resin solution or suspension.
Claim 30
Dependent Claim
33 words
The process of claim 28 in which said amine is hexamethylenetetramine, the phenol component in both said Novolac and said resol resins is phenol and the aldehyde in said resol resin is formaldehyde.
Claim 31
Dependent Claim
18 words
The process of claim 29 in which the furfuraldehyde is approximately 100 molar percent of the aldehyde component.
Claim 32
Dependent Claim
21 words
The process of claim 30 in which the amount of graphite is 40-60 percent by weight of the total moldable composition.
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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) | 1989-11-24 | 1990-05-26 | 1990-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-24 | 1994-05-26 | 1994-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-24 | 1998-05-26 | 1998-11-25 | $7700.00 | Window Closed / Lapsed |