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US4621015A
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US
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Low density, modified polyimide foams and methods of making same
Assignee: IMI-TECH Corp ELK GROVE ILL A CORP OF
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Filing: 1984-03-07
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Granted: 1986-11-04
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Expires: 2004-03-07
Abstract
Abstract Methods of making low density modified polyimide/polyimide-amide foams and the resulting compositions. An N-substituted aliphatic imide is prepared by reacting a suitable aromatic dianhydride with a suitable oxime. A polyimide forming material is prepared by dissolving the N-substituted aliphatic imide in an esterifying solvent, then adding a suitable aromatic diamine. This material is dried to a powder. A suitable hydrated compound which is stable up to at least about 100° C. is mixed with the powder. A foam is then produced by heating the material to reaction temperature for a period sufficient to produce a stable foam. The material melts, then spontaneously expands into a foam which becomes self supporting and cures to a resilient flexible foam. The addition of the hydrated compound is found to result in an exceptionally low density foam. Depending upon heating conditions, a polyimide, polyimide-amide or mixture thereof may be produced, resulting in foams having selectively variable physical properties.
Inventors
- 👤 John V. Long
- 👤 John Gagliani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:47
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/34; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08J9/02; C08L; C08L79/00; C08L79/04; C08L79/08; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249982; Y10T428/249985; Y10T428/249987; Y10T428/249988; Y10T428/249989; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
154 words
A resilient, flame resistant modified polyimide foam product produced by the following process steps; reacting an oxime having general formula ##STR8## where "x" is a positive integer from 1-5, with an aromatic dianhydride in a mole ratio of oxime to dianhydride up to about 1.5:1 to produce an N-substituted aliphatic imide; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; drying the resulting solution to produce a powdered prepolymer; blending with said powdered prepolymer from about 0.05 to 10 wt. %, based on prepolymer weight, of a hydrated compound which is stable up to at least about 100 C.; shaping the blended material with a shaping means; and heating said shaped blended material to a selected foaming temperature of from about 120 C. to about 320 C. for a period of from about 10 to 60 minutes; whereby said shaped blended material melts and spontaneously foams producing a foam product.
Claim 2
Dependent Claim
154 words
A resilient, flame resistant modified polyimide foam product produced by the following process steps; reacting an oxime having general formula ##STR8## where "x" is a positive integer from 1-5, with an aromatic dianhydride in a mole ratio of oxime to dianhydride up to about 1.5:1 to produce an N-substituted aliphatic imide; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; drying the resulting solution to produce a powdered prepolymer; blending with said powdered prepolymer from about 0.05 to 10 wt. %, based on prepolymer weight, of a hydrated compound which is stable up to at least about 100 C.; shaping the blended material with a shaping means; and heating said shaped blended material to a selected foaming temperature of from about 120 C. to about 320 C. for a period of from about 10 to 60 minutes; whereby said shaped blended material melts and spontaneously foams producing a foam product.
Claim 3
Dependent Claim
44 words
The invention as defined in the claim 1 wherein the product produced by said process is a composite product and is produced by the further step of bonding a reinforcing layer of material to a surface of said foam product with a polyimide resin.
Claim 4
Dependent Claim
15 words
The invention as defined in claim 1 wherein said shaping means is a tubular mold.
Claim 5
Dependent Claim
37 words
The invention as defined in claim 1 in which the shaping means is an extrusion device, the blend is heated to melt therein, and the resulting foam is conveyed through a die to produce a shaped article.
Claim 6
Dependent Claim
167 words
A resilient, flame resistant modified polyimide foam product produced from the following process steps: reacting an oxime having the general formula ##STR9## where "x" is an integer from 1 to 5, with an aromatic dianhydride in a mole ratio of oxime to dianhydride up to about 1.5:1 to produce an N-substituted aliphatic imide; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; adding thereto a diamine; drying the resulting solution to produce a powdered prepolymer; and heating the powdered prepolymer to a selected foaming temperature of from about 120 C. to about 320 C. for a period of from about 10 to about 60 minutes; the improvement comprising; after drying the solution to produce said prepolymer, blending with said powdered prepolymer from about 0.05 to 10 wt. %, based on prepolymer weight, of a hydrated compound which is stable up to a temperature of at least about 100 C.; and shaping the blended material with a shaping means prior to the heating steps.
Claim 7
Dependent Claim
167 words
A resilient, flame resistant modified polyimide foam product produced from the following process steps: reacting an oxime having the general formula ##STR9## where "x" is an integer from 1 to 5, with an aromatic dianhydride in a mole ratio of oxime to dianhydride up to about 1.5:1 to produce an N-substituted aliphatic imide; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; adding thereto a diamine; drying the resulting solution to produce a powdered prepolymer; and heating the powdered prepolymer to a selected foaming temperature of from about 120 C. to about 320 C. for a period of from about 10 to about 60 minutes; the improvement comprising; after drying the solution to produce said prepolymer, blending with said powdered prepolymer from about 0.05 to 10 wt. %, based on prepolymer weight, of a hydrated compound which is stable up to a temperature of at least about 100 C.; and shaping the blended material with a shaping means prior to the heating steps.
Claim 8
Dependent Claim
43 words
The invention as defined in claim 5 wherein the product produced by said process is a composite product and is produced by the further step of bonding a reinforcing layer of material to a surface of said foam product with a polyimide resin.
Claim 9
Dependent Claim
15 words
The invention as defined in claim 5 wherein said shaping means is a tubular mold.
Claim 10
Dependent Claim
36 words
The invention as defined in claim 5 wherein the shaping means is an extrusion device, the blend is heated to melt therein, and the resulting foam is conveyed through a die to produce a shaped article.
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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) | 1989-11-03 | 1990-05-05 | 1990-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-03 | 1994-05-05 | 1994-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-03 | 1998-05-05 | 1998-11-04 | $7700.00 | Window Closed / Lapsed |