Abstract The invention comprises solid, tack-free, thermo-setting linear polyimides of benzophenone tetracarboxylic dianhydride and a saturated aliphatic diamine having from three to 12 carbon atoms, containing not more than a 2% excess of dianhydride or diamine over the amount needed to form the linear polyimide. The adhesives of the present invention have softening points between 150* C. and 300* C., inherent viscosities of about 0.1 and 2.0 as measured from a 0.5% solution of polyimide in m-cresol at 25* C. and substantially complete solubilities in m-cresol at 25* C. in the ratio of 10% by weight of polymer to 90% by weight of solvent, said polyimides releasing not more than 1% by weight of volatiles upon being heated for a period of 10 hours at 200* C. and thereby rendered thermally set.
The polyimide of claim 1, wherein said diamine is hexamethylene diamine.
Claim 2
Dependent Claim
43 words
at least 70 parts by weight of a solvent therefor which contains at least 40% by weight of cresol and the remainder, if any, is selected from chlorinated hydrocarbons and aromatic hydrocarbons, provided that the total of (1) and (2) is 100 parts.
Claim 3
Dependent Claim
10 words
A dry, fusible powder comprising a polyimide of claim 1.
Claim 4
Dependent Claim
8 words
An adhesive comprising a polyimide of claim 1.
Claim 5
Dependent Claim
9 words
A polyimide according to claim 1 in film form.
Claim 6
Dependent Claim
3 words
A solution of
Claim 7
Dependent Claim
12 words
A solution according to claim 6 in which the solvent is m-cresol.
Claim 8
Dependent Claim
17 words
A solution according to claim 6 in which the solvent is a mixture of m-cresol and p-cresol.