Abstract: Disclosed is a polyimidesiloxane adhesive made by reacting in a solution of an organic solvent a dianhydride selected from the group consisting of biphenyl dianhydride and oxydiphthalic anhydride with an approximately stoichiometric amount of a diamine. The diamine is a mixture of about 5 to about 30 mole % of a siloxane-containing diamine and about 70 to about 95 mole % of a non-siloxane containing diamine. The non-siloxane containing diamine is a mixture of about 10 to about 90 mole % each of at least two of the diamines 2,2-bis(4[4-aminophenoxy]phenyl) propane, &agr;,&agr;′-bis(4-aminophenyl)-1,4-diisopropylbenzene, 3,3′-diaminophenylsulfone, and 1,3-bis(3-aminophenoxy)benzene. The adhesive can be made into one, two, and three-layer tapes (or dispensed in other ways) which have a high Tg and a relatively low bonding temperature.

Abstract: Disclosed is a composition of (1) a substituted benzaldehyde having the general formula ##STR1## where X is a leaving group in the ortho or para position, (2) a mercaptide having the general formula MSR' in an amount about stoichiometric to about 20 mole % in excess of stoichiometric with the amount of said substituted benzaldehyde, where M is an alkali metal and R' is alkyl or haloalkyl from C.sub.1 to C.sub.8 or aryl, aralkyl, or alkyl from C.sub.6 to C.sub.12, (3) sufficient water to dissolve said mercaptide and MX, (4) about 0.1 to about 5 mole %, based on said substituted benzaldehyde, of a phase transfer catalyst, and (5) 0 to about 100 wt %, based on total composition weight, of a water-immiscible organic solvent. Heating the composition to a temperature between about room temperature and 100.degree. C. results in the formation of a substituted mercapto-benzaldehyde.