Patent US4983244A successfully refreshed from Google Patents.
US4983244A
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Process for producing graphite blocks
Assignee: Panasonic Holdings Corp
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Filing: 1989-09-19
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Granted: 1991-01-08
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Expires: 2009-09-19
Abstract
Abstract Graphite blocks are produced by a process wherein one or plural polymer films having a thickness of from 1 to 400 μm and selected from aromatic polyimides, aromatic polyamides and polyoxadiazoles are heat treated to obtain carbonaceous films. A plurality of the carbonaceous films are hot pressure under certain conditions to obtain thick graphite blocks. The blocks have a remarkably improved rocking characteristic and are useful as radiation optical elements such as X-ray or neutron ray monochromators or filters. The blocks may be curved to obtain bent-type graphite articles.
Inventors
- 👤 Mutsuaki Murakami
- 👤 Susumu Yoshimura
- 👤 Naomi Nishiki
- 👤 Katsuyuki Nakamura
- 👤 Kazuhiro Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:14
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/52; C04B35/524; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1043; Y10T156/1044; Y10T156/1048
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
115 words
A process for producing a graphite block, which comprises separately forming a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles; heat treating the films at a temperature sufficient to convert them to carbonaceous films; superposing the plurality of carbonaceous films; and subjecting the plurality of superposed carbonaceous films to hot pressing first at a pressure not higher than 20 kg/cm 2 and a temperature not higher than 2800° C. and then at a pressure higher than 20 kg/cm 2 and a temperature higher than 2800° C. for a time sufficient for graphitization to occur and to form a graphite block.
Claim 2
Dependent Claim
115 words
A process for producing a graphite block, which comprises separately forming a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles; heat treating the films at a temperature sufficient to convert them to carbonaceous films; superposing the plurality of carbonaceous films; and subjecting the plurality of superposed carbonaceous films to hot pressing first at a pressure not higher than 20 kg/cm 2 and a temperature not higher than 2800° C. and then at a pressure higher than 20 kg/cm 2 and a temperature higher than 2800° C. for a time sufficient for graphitization to occur and to form a graphite block.
Claim 3
Dependent Claim
19 words
The process of claim 1, wherein the heat treatment is effected at a temperature of 450° to 2000° C.
Claim 4
Dependent Claim
22 words
The process of claim 1, wherein the heat treatment step and the hot pressing step are conducted in an inert gas atmosphere.
Claim 5
Dependent Claim
122 words
A process for producing a graphite block, which comprises separately forming a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles; heat treating the films at a temperature sufficient to convert them to carbonaceous films; superposing the plurality of carbonaceous films; and subjecting the plurality of superposed carbonaceous films to hot pressing at a temperature not lower than 800° C. and at a pressure first increasing from zero to not higher than 200 kg/cm 2 and then decreasing to a level not lower than zero; and repeating the increase and decrease of pressure during hot pressing up to several tens of times to obtain a wrinkle-free graphite block.
Claim 6
Dependent Claim
122 words
A process for producing a graphite block, which comprises separately forming a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles; heat treating the films at a temperature sufficient to convert them to carbonaceous films; superposing the plurality of carbonaceous films; and subjecting the plurality of superposed carbonaceous films to hot pressing at a temperature not lower than 800° C. and at a pressure first increasing from zero to not higher than 200 kg/cm 2 and then decreasing to a level not lower than zero; and repeating the increase and decrease of pressure during hot pressing up to several tens of times to obtain a wrinkle-free graphite block.
Claim 7
Dependent Claim
121 words
The process of claim 4, wherein the hot pressing step is conducted at a temperature of up to 2000° C. and first at a pressure of up to 20 kg/cm 2 for a given period of time, and then decreasing the pressure to a level not lower than zero; repeating the hot pressing step up to several tens of times; and then further hot pressing the films at a temperature higher than 2000° C. and a pressure higher than 20 kg/cm 2 for a given period of time, and then decreasing the pressure to a level not higher than 20 kg/cm 2 ; and repeating the further hot pressing step up to several tens of times to obtain a graphite block.
Claim 8
Dependent Claim
113 words
A process for producing a graphite block, which comprises heat treating a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles at a temperature sufficient to convert the films to carbonaceous films; and hot pressing the plurality of the carbonaceous films first at a pressure of not higher than 20 kg/cm 2 and a temperature not higher than 2800° C. for a given period of time, and then at a pressure higher than 20 kg/cm 2 and a temperature higher than 2800° C. for a period of time sufficient for graphitization to occur and to form a graphite block.
Claim 9
Dependent Claim
113 words
A process for producing a graphite block, which comprises heat treating a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles at a temperature sufficient to convert the films to carbonaceous films; and hot pressing the plurality of the carbonaceous films first at a pressure of not higher than 20 kg/cm 2 and a temperature not higher than 2800° C. for a given period of time, and then at a pressure higher than 20 kg/cm 2 and a temperature higher than 2800° C. for a period of time sufficient for graphitization to occur and to form a graphite block.
Claim 10
Dependent Claim
21 words
The process of claim 6, wherein the heat treatment is effected at a temperature of 400° to 1000° C. under pressure.
Claim 11
Dependent Claim
45 words
The process of claim 6, wherein the films have a face where the pressure is applied; and the heat treatment is effected at a temperature of 400° to 1000° C. while inhibiting the expansion of the films in a direction perpendicular to the film's face.
Claim 12
Dependent Claim
32 words
The process of claim 6, wherein the hot pressing step is conducted at a temperature not lower than 800° C. and the pressure is applied intermittently to produce a wrinkle-free graphite block.
Claim 13
Dependent Claim
122 words
The process of claim 9, wherein the hot pressing step is effected at a temperature of up to 2000° C. and first at a pressure of up to 20 kg/cm 2 for a given period of time and then decreasing the pressure to a value of down to zero; repeating the hot pressing step up to several tens of times; then further hot pressing the films at a temperature higher than 2000° C. and first at a pressure higher than 20 kg/cm 2 for a given period of time and then decreasing the pressure to a level not higher than 20 kg/cm 2 ; and repeating the further hot pressing step up to several tens of times to obtain a graphite block.
Claim 14
Dependent Claim
117 words
A process for producing a curved graphite article which comprises forming a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles; heat treating the films at a temperature sufficient to convert the films to carbonaceous films; superposing the plurality of carbonaceous films; and subjecting the plurality of superposed carbonaceous films to hot pressing along a curved surface first at a pressure not higher than 20 kg/cm 2 and a temperature not higher than 2800° C. and then at a pressure higher than 20 kg/cm 2 and a temperature higher than 2800° C. for a time sufficient for graphitization of the product to occur.
Claim 15
Dependent Claim
117 words
A process for producing a curved graphite article which comprises forming a plurality of 1 to 400 μm thick films of a polymer selected from the group consisting of aromatic polyimides, aromatic polyamides and polyoxadiazoles; heat treating the films at a temperature sufficient to convert the films to carbonaceous films; superposing the plurality of carbonaceous films; and subjecting the plurality of superposed carbonaceous films to hot pressing along a curved surface first at a pressure not higher than 20 kg/cm 2 and a temperature not higher than 2800° C. and then at a pressure higher than 20 kg/cm 2 and a temperature higher than 2800° C. for a time sufficient for graphitization of the product to occur.
Claim 16
Dependent Claim
34 words
The process of claim 11, wherein the heat treatment is effected at a temperature which is higher than the decomposition temperature of the polymer film and in the range of 400° to 2000° C.
Claim 17
Dependent Claim
19 words
The process of claim 11, wherein the heat treatment is effected at a temperature not lower than 1000° C.
Claim 18
Dependent Claim
20 words
The process of claim 11, wherein the thickness of each of the plurality of films is 1 to 200 μm.
Claim 19
Dependent Claim
39 words
The process of claim 11, wherein the polymer films and the resulting carbonaceous films have a dome-shaped form; and the plurality of dome-shaped carbonaceous films are hot pressed along a dome-shaped surface to form a double bent-type graphite article.
Claim 20
Dependent Claim
43 words
The process of claim 15, wherein each dome-shaped film is obtained by applying a solvent solution of the polymer onto a substrate; evaporating part of the solvent to obtain a film; and subjecting the resultant film to vacuum molding in a dome-shaped mold.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |