Claims
- 1. A process for producing high temperature and flame resistant closed cell foam structure formed by the following process steps:
- reacting an oxoimine having the general formula ##STR6## where "x" is a positive integer from 2 to 4, with an aromatic tetracarboxylic acid dianhydride in a mole ratio thereof between about 0.05:1 and 1.5:1 to produce an N-substituted imide;
- esterfying said N-substituted imide by mixing therewith a reactive solvent;
- adding thereto at least one diamine;
- drying the resulting liquid composition;
- reducing the dried material to an average particle diameter of from about 0.5 to 10 mm.;
- placing a suitable quantity of said particles into a honeycomb structure; and
- heating said particles to a temperature in the range of about 90.degree. to 150.degree. C.;
- whereby said particles expand producing a closed cell foam of substantial uniform density throughout the honeycomb structure forming a high strength structure with cell foam bonded to the honeycomb results.
- 2. The process according to claim 1 including the further step of filling a honeycomb structure with said macroballoons, then heating said structure to a temperature sufficient to cause said macroballoons to bond to said honeycomb.
- 3. The process according to claim 1 including the further step of mixing said macroballoons with a portion of said liquid composition and heating the filled honeycomb to a temperature of about 90.degree. to 150.degree. C. to dry and cure said resin.
- 4. A process for producing high temperature and flame resistant closed cell foam structure formed by the following process steps:
- reacting an oximine having the general formula ##STR7## where "x" is a positive integer from 2 to 4, with an aromatic tetracarboxylic acid dianhydride in a mole ratio therof between 0.05:1 and 1.5:1 to produce an N-substituted imide;
- esterfying said N-substituted imide by mixing therewith a reactive solvent;
- adding thereto at least one diamine;
- drying the resulting liquid composition;
- reducing the dried material to an average particle diameter of from about 0.5 to 10 mm.;
- placing a suitable quantity of said particles between spaced parallel sheets; and
- heating said particles to a temperature in the range of about 90.degree. to 150.degree. C.;
- whereby said particles expand producing a composite closed cell foam layer of substantially uniform density bonded to said sheets.
- 5. The process according to claim 4 further including the step of compressing the bonded composite at a temperature of about 150.degree. to 200.degree. C. to increase density.
- 6. High temperature and flame resistant macroballoons produced by the following process steps:
- reacting an oximine having the general formula ##STR8## where "x" is a positive integer from 2 to 4, with an aromatic tetracarboxylic acid dianhydride in a mole ratio therof between 0.05:1 and 1.5:1 to produce and N-substituted imide;
- esterfying said N-substituted imide by mixing therewith a reactive solvent;
- adding thereto at least one diamine;
- drying the resulting liquid composition;
- reducing the dried material to an average particle diameter of from about 0.5 to 10 mm.; and
- foaming said particles by feeding them into a moving hot air stream, whereby discrete macroballoons are produced.
Parent Case Info
This is a division, of application Ser. No. 423,802, filed Sept. 27, 1982.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4355120 |
Gagliani et al. |
Oct 1982 |
|
4360604 |
Gagliani et al. |
Nov 1982 |
|
4361453 |
Gagliani et al. |
Nov 1982 |
|
Divisions (1)
|
Number |
Date |
Country |
Parent |
423802 |
Sep 1982 |
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