Modified polyimide foams and methods of making same

Claim 1

The method of making a resilient, flame resistant modified polyimide foam having a selected compressive resistance which comprises the steps of: reacting an aromatic dianhydride with an oximine having the general formula: CH.sub.2 --(CH.sub.2).sub.x --NHCO wherein "X" is an integer from 2 to 4, in a selected mole ratio of oxoimine to dianhydride between about 0.5:1 and about 0.05:1 to produce an N-substituted aliphatic imide; dissolving said imide in a reactive solvent esterifying agent to exterify said imide; adding thereto a diamine; drying the resulting solution; and heating the dry material 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; whereby a resilient foam having a selected compressive resistance in accordance with the selected oxoimine to dianhydride mole ratio, the compressive resistance being inversely proportional to the oxoimine quantity.

Claim 2

The method of making a resilient, flame resistant modified polyimide foam having a selected compressive resistance which comprises the steps of: reacting an aromatic dianhydride with an oximine having the general formula: CH.sub.2 --(CH.sub.2).sub.x --NHCO wherein "X" is an integer from 2 to 4, in a selected mole ratio of oxoimine to dianhydride between about 0.5:1 and about 0.05:1 to produce an N-substituted aliphatic imide; dissolving said imide in a reactive solvent esterifying agent to exterify said imide; adding thereto a diamine; drying the resulting solution; and heating the dry material 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; whereby a resilient foam having a selected compressive resistance in accordance with the selected oxoimine to dianhydride mole ratio, the compressive resistance being inversely proportional to the oxoimine quantity.

Claim 14

The method of making a modified polyimide foam having a selected compressive resistance comprising a mixture of polyimide and polyimide-amide resins with the polyimide-amide predominating which comprises the steps of: mixing together an aromatic dianhydride selected from pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and mixtures thereof and an oxoimine having the general formula: ##STR8## wherein "x" is an integer from 2 to 4, the mole ratio of oxoimine to dianhydride being selected within the range of from about 0.5:1 to about 0.05:1 in accordance with the final foam compressive resistance desired; heating the mixture to a temperature of from about 150° C. to about 200° C. for from about 5 to about 90 minutes to react said dianhydride with said oxoimine to produce an N-substituted aliphatic imide; cooling the mixture to a temperature of from about 40° C. to about 70° C.; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; heating the imide solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of from about 60 to about 90 minutes to esterify said imide; adding thereto about 1.0 M 4,4'-diaminodiphenyl methane per 1.0 M of dianhydride; heating the resulting solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of about 2 to about 30 minutes; drying the solution at a temperature of from about 60° C. to about 70° C. for a period of about 60 to about 240 minutes to produce a dry material; and foaming said dry material by heating to a temperature of about 120° C. to about 220° C. in a pre-heated oven for from about 10 to about 40 minutes; whereby a resilient foam having a selected compressive resistance in accordance with the selected oxoimine to dianhydride mole ratio, the compressive resistance being inversely proportional to the oxoimine quantity.

Claim 15

The method of making a modified polyimide foam having a selected compressive resistance comprising a mixture of polyimide and polyimide-amide resins with the polyimide-amide predominating which comprises the steps of: mixing together an aromatic dianhydride selected from pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and mixtures thereof and an oxoimine having the general formula: ##STR8## wherein "x" is an integer from 2 to 4, the mole ratio of oxoimine to dianhydride being selected within the range of from about 0.5:1 to about 0.05:1 in accordance with the final foam compressive resistance desired; heating the mixture to a temperature of from about 150° C. to about 200° C. for from about 5 to about 90 minutes to react said dianhydride with said oxoimine to produce an N-substituted aliphatic imide; cooling the mixture to a temperature of from about 40° C. to about 70° C.; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; heating the imide solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of from about 60 to about 90 minutes to esterify said imide; adding thereto about 1.0 M 4,4'-diaminodiphenyl methane per 1.0 M of dianhydride; heating the resulting solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of about 2 to about 30 minutes; drying the solution at a temperature of from about 60° C. to about 70° C. for a period of about 60 to about 240 minutes to produce a dry material; and foaming said dry material by heating to a temperature of about 120° C. to about 220° C. in a pre-heated oven for from about 10 to about 40 minutes; whereby a resilient foam having a selected compressive resistance in accordance with the selected oxoimine to dianhydride mole ratio, the compressive resistance being inversely proportional to the oxoimine quantity.

Claim 18

The method of making a modified polyimide foam having a selected compressive resistance comprising a mixture of polyimide and polyimide-amide with the polyimide predominating which comprises the steps of: mixing together an aromatic dianhydride selected from pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and mixtures thereof and an oxoimine having the general formula: ##STR9## wherein "x" is an integer from 2 to 4, the mole ratio of oxoimine to dianhydride being selected within the range of from about 0.5:1 to about 0.05:1 in accordance with the desired final foam compressive resistance, said compressive resistance being inversely proportional to the oxoimine quantity; heating the mixture to a temperature of from about 150° C. to about 200° C. for from about 5 to about 90 minutes to react said dianhydride with said oxoimine to produce an N-substituted aliphatic imide; cooling the mixture to a temperature of from about 40° C. to about 70° C.; dissolving said imide in a reacting solvent esterifying agent to esterify said imide; heating the imide solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of from about 60 to about 90 minutes to esterify said imide; adding thereto about 1.0 M 4,4'-diaminodiphenyl methane per about 1.0 M of dianhydride; heating the resulting solution of reflux at a temperature of from about 70° C. to about 80° C. for a period of about 2 to about 30 minutes; drying the solution at a temperature of from about 60° C. to about 70° C. for a period of about 60 to about 240 minutes to produce a dry material; and foaming said dry material by heating to a temperature of about 230° C. to about 320° C. in a pre-heated oven for about 30 to about 60 minutes; whereby a resilient flame resistant modified polyimide foam having selected compressive resistance characteristics is produced, consisting primarily of polyimide resin.

Claim 19

The method of making a modified polyimide foam having a selected compressive resistance comprising a mixture of polyimide and polyimide-amide with the polyimide predominating which comprises the steps of: mixing together an aromatic dianhydride selected from pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and mixtures thereof and an oxoimine having the general formula: ##STR9## wherein "x" is an integer from 2 to 4, the mole ratio of oxoimine to dianhydride being selected within the range of from about 0.5:1 to about 0.05:1 in accordance with the desired final foam compressive resistance, said compressive resistance being inversely proportional to the oxoimine quantity; heating the mixture to a temperature of from about 150° C. to about 200° C. for from about 5 to about 90 minutes to react said dianhydride with said oxoimine to produce an N-substituted aliphatic imide; cooling the mixture to a temperature of from about 40° C. to about 70° C.; dissolving said imide in a reacting solvent esterifying agent to esterify said imide; heating the imide solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of from about 60 to about 90 minutes to esterify said imide; adding thereto about 1.0 M 4,4'-diaminodiphenyl methane per about 1.0 M of dianhydride; heating the resulting solution of reflux at a temperature of from about 70° C. to about 80° C. for a period of about 2 to about 30 minutes; drying the solution at a temperature of from about 60° C. to about 70° C. for a period of about 60 to about 240 minutes to produce a dry material; and foaming said dry material by heating to a temperature of about 230° C. to about 320° C. in a pre-heated oven for about 30 to about 60 minutes; whereby a resilient flame resistant modified polyimide foam having selected compressive resistance characteristics is produced, consisting primarily of polyimide resin.

Claim 22

The method of making a modified polyimide foam having a selected compressive resistance comprising a mixture of polyimide and polyimide-amide with significant portions of both polyimide and polyimide-amide which comprises the steps of: mixing together an aromatic dianhydride selected from pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and mixtures thereof and an oxoimine having the general formula: ##STR10## wherein "x" is an integer from 2 to 4, the mole ratio of oxoimine to dianhydride being selected within the range of from about 1.5:1 to about 0.05:1 in accordance with the desired final foam compressive resistance, said compressive resistance being inversely proportional to the oxoimine quantity; heating the mixture to a temperature of from about 150° C. to about 200° C. for from about 5 to about 90 minutes to react said dianhydride with said oxoimine to produce an N-substituted aliphatic imide; cooling the mixture to a temperature of from about 40° C. to about 70° C.; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; heating the imide solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of from about 60 to about 90 minutes to esterify said imide; adding thereto about 1.0 M 4,4'-diaminodiphenyl methane per about 1.0 M of dianhydride; heating the resulting solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of about 2 to about 30 minutes; drying the solution at a temperature of from about 60° C. to about 70° C. for a period of about 60 to about 240 minutes to produce a dry material; and foaming said dry material by heating to a temperature of from about 210° C. to about 250° C. for a period of about 30 to about 45 minutes; whereby a resilient flame resistant modified polyimide foam having selected compressive resistance characteristics is produced containing significant portions of both polyimide and polyimide-amide resins.

Claim 23

The method of making a modified polyimide foam having a selected compressive resistance comprising a mixture of polyimide and polyimide-amide with significant portions of both polyimide and polyimide-amide which comprises the steps of: mixing together an aromatic dianhydride selected from pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and mixtures thereof and an oxoimine having the general formula: ##STR10## wherein "x" is an integer from 2 to 4, the mole ratio of oxoimine to dianhydride being selected within the range of from about 1.5:1 to about 0.05:1 in accordance with the desired final foam compressive resistance, said compressive resistance being inversely proportional to the oxoimine quantity; heating the mixture to a temperature of from about 150° C. to about 200° C. for from about 5 to about 90 minutes to react said dianhydride with said oxoimine to produce an N-substituted aliphatic imide; cooling the mixture to a temperature of from about 40° C. to about 70° C.; dissolving said imide in a reactive solvent esterifying agent to esterify said imide; heating the imide solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of from about 60 to about 90 minutes to esterify said imide; adding thereto about 1.0 M 4,4'-diaminodiphenyl methane per about 1.0 M of dianhydride; heating the resulting solution to reflux at a temperature of from about 70° C. to about 80° C. for a period of about 2 to about 30 minutes; drying the solution at a temperature of from about 60° C. to about 70° C. for a period of about 60 to about 240 minutes to produce a dry material; and foaming said dry material by heating to a temperature of from about 210° C. to about 250° C. for a period of about 30 to about 45 minutes; whereby a resilient flame resistant modified polyimide foam having selected compressive resistance characteristics is produced containing significant portions of both polyimide and polyimide-amide resins.