Patent US4996109A successfully refreshed from Google Patents.
US4996109A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hard foam cores for laminates
Assignee: Roehm GmbH Darmstadt
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Filing: 1989-07-31
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Granted: 1991-02-26
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Expires: 2009-07-31
Abstract
Abstract Rigid foamed polymethacrylimide synthetic resin containing from 0.1 to 10 percent by weight of electrically conductive particles such as conductive carbon black exhibit improved properties when used in rapidly flowing streams of gases, are particularly suitable for use as a core material in laminates for aircraft construction, and are prepared by heating a copolymer of methacrylic acid and methyacrylonitrile containing a blowing agent and conductive particles.
Inventors
- 👤 Manfred Krieg
- 👤 Norbert Rau
- 👤 Werner Ude
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:07
CPC Classifications
B; B32; B32B; B32B5/00; B32B5/18; B32B15/00; B32B15/04; B32B15/046; B32B27/00; B32B27/06; B32B27/065; C; C08; C08J; C08J9/00; C08J9/0066; C08J9/04; C08J9/12; C08J9/14; C08J9/142; C08K; C08K3/00; C08K3/01; C08K3/02; C08K3/04; H; H01; H01B; H01B1/00; H01B1/20; H01B1/24; B32B2266/00; B32B2266/02; B32B2266/0214; B32B2266/0221; B32B2605/00; B32B2605/18; C08J2333/00; C08J2333/24; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249986; Y10T428/25; Y10T428/256; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
18 words
A rigid foamed polymethacrylimide synthetic resin comprising from 0.1 to 10 percent by weight of electrically conductive particles.
Claim 2
Dependent Claim
18 words
A rigid foamed polymethacrylimide synthetic resin comprising from 0.1 to 10 percent by weight of electrically conductive particles.
Claim 3
Dependent Claim
22 words
A rigid foamed resin as in claim 1 wherein said electrically conductive particles range in size from 10 nanometers to 10 millimeters.
Claim 4
Dependent Claim
19 words
A rigid foamed resin as in claim 1 wherein said electrically conductive particles are particles of conductive carbon black.
Claim 5
Dependent Claim
25 words
A rigid foamed resin as in claim 1 in the form of a sheet or board which is from 1 millimeter to 100 millimeters thick.
Claim 6
Independent Claim
67 words
A method for making a rigid foamed polymethacrylimide synthetic resin which comprises free radically copolymerizing a mixture of monomers of methacrylic acid and methacrylonitrile to form a copolymer, said mixture further comprising a blowing agent evolving gas when heated and from 0.1 to 10 percent, by weight of said copolymer, of electrically conductive particles, and then heating said copolymer to form and foam said rigid polymethacrylimide resin.
Claim 7
Independent Claim
67 words
A method for making a rigid foamed polymethacrylimide synthetic resin which comprises free radically copolymerizing a mixture of monomers of methacrylic acid and methacrylonitrile to form a copolymer, said mixture further comprising a blowing agent evolving gas when heated and from 0.1 to 10 percent, by weight of said copolymer, of electrically conductive particles, and then heating said copolymer to form and foam said rigid polymethacrylimide resin.
Claim 8
Dependent Claim
15 words
A method as in claim 5 wherein said blowing agent is a lower aliphatic alcohol.
Claim 9
Dependent Claim
21 words
A method as in claim 5 wherein said mixture, prior to polymerization, is agitated at high frequency with a rotor-stator mixer.
Claim 10
Dependent Claim
26 words
A method as in claim 5 wherein said mixture additionally comprises a monomer selected from the group consisting of styrene and cyclic derivatives of maleic acid.
Claim 11
Dependent Claim
33 words
A laminate comprising a core layer of a rigid foamed polymethacrylimide synthetic resin as in claim 1 and at least one further layer bonded to at least one side of said core layer.
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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) | 1994-02-25 | 1994-08-27 | 1995-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-25 | 1998-08-27 | 1999-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-25 | 2002-08-27 | 2003-02-26 | $7700.00 | Window Closed / Lapsed |