Novel copolyamideimides, prepolymers therefor and method for their preparation
AssigneeGeneral Electric Company
InventorsDonald A. Bolon, Thomas B. Gorczyca
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Abstract
Carboxy-terminated prepolymers are prepared by the reaction of a diamine, preferably an aromatic diamine, or a mixture thereof with a triamine, with a carboxy anhydride such as trimellitic anhydride and a dianhydride such as bisphenol A dianhydride. The prepolymers, or functional derivatives thereof, are then reacted with a diisocyanate or diamine, or a mixture thereof with a triisocyanate or triamine, preferably an aromatic diisocyanate, to produce copolyamideimides. The products prepared using triamines or triisocyanates are crosslinked. Other products containing alkyl or alicyclic groups attached to aromatic radicals can be oxidatively crosslinked, e.g., by heating in air.
Claims16
A method for preparing a crosslinked polymer which comprises the steps of:
- (1) preparing a carboxy-terminated prepolymer by reacting, under conditions whereby all water of reaction is removed:
- (A) at least one polyamine having the formula
- H.sub.2 N--R.sup.1 --NH.sub.2, (I)
- wherein R.sup.1 is a divalent aromatic hydrocarbon radical containing about 6-20 carbon atoms or halogenated derivative thereof, alkylene or cycloalkylene radical containing about 2-20 carbon atoms, or bis-alkylenepoly(dialkylsiloxane) radical;
- with
- (B) at least one carboxy anhydride having the formula ##STR12## wherein R.sup.2 is a trivalent aliphatic radical containing about 2-20 carbon atoms or aromatic radical containing about 6-20 carbon atoms, and
- (C) at least one dianhydride having the formula ##STR13## wherein R.sup.3 is a tetravalent aliphatic radical containing about 2-20 carbon atoms or aromatic radical containing about 6-20 carbon atoms;
- the molar ratio of reagent C to reagent B being at least about 0.25:1 and the ratio of equivalents of reagent A to anhydride equivalents of reagents B and C combined being about 1:1;
- (2) preparing a copolyamideimide by reacting, at a temperature within the range of about 150.degree.-225.degree. C.,
- (D) said carboxy-terminated prepolymer with (E) at least one compound selected from the group consisting of polyisocyanates having the formula
- OCN--R.sup.4 --NCO, (V)
- polyamines having the formula
- R.sup.5 NH--R.sup.4 --NHR.sup.6, (VI)
- and functional derivatives thereof, wherein:
- R.sup.4 is a divalent polymeric radical, aromatic hydrocarbon radical containing about 6-20 carbon atoms or halogenated derivative thereof, alkylene or cycloalkylene radical containing about 2-20 carbon atoms, or bis-alkylenepoly(dialkylsiloxane) radical;
- and
- each of R.sup.5 and R.sup.6 is independently hydrogen or a lower hydrocarbon radical,
- the structural units in said copolyamideimide containing at least one aromatic radical having at least one alkyl or alicyclic substituent;
- and
- (3) contacting said copolyamideimide with an oxidizing agent and heating said copolyamideimide at a temperature within the range from its glass transition temperature to just below its degradation temperature.
A method for preparing a crosslinked polymer from a copolyamideimide comprising structural units having the formula ##STR16## wherein each of R.sup.1 and R.sup.4 is independently a divalent aromatic hydrocarbon radical containing about 6-20 carbon atoms or halogenated derivative thereof, alkylene or cycloalkylene radical containing about 2-20 carbon atoms, or bis-alkylenepoly(dialkylsiloxane) radical;
- R.sup.2 is a trivalent aliphatic radical containing about 2-20 carbon atoms or aromatic radical containing about 6-20 carbon atoms;
- R.sup.3 is a tetravalent aliphatic radical containing about 2-20 carbon atoms or aromatic radical containing about 6-20 carbon atoms;
- each of R.sup.5 and R.sup.6 is independently hydrogen or a hydrocarbon radical;
- and
- the average value of n is at least 0.5;
- said structural units of formula XVII containing at least one aromatic radical having at least one alkyl or alicyclic substituent;
- which comprises contacting said copolyamideimide with an oxidizing agent and heating said copolyamideimide at a temperature within the range from its glass transition temperature to just below its degradation temperature.
Dependencies are inferred from the claim text.