Patent GB-1083168-A (GB)
Title: Adhesive mixtures
IPC: C08G73/10
Filed: 1964-10-28
Abstract: The invention comprises adhesive mixtures of (A) a polyamide having end-groups of formula -NH-R2-NH2 and recurring units of formula <FORM:1083168/C3/1> where the two pairs of carbonyl groups 1, 2 and 3, 4 are attached to adjacent or peri-carbon atoms in R1, and R1 and R2, which may vary from one structural unit to another are aliphatic, aromatic, carbocyclic or heterocyclic and (B) at least 15 mole per cent of a diamine of formula NH2-R2-NH2, the polymer containing at least 30 aromatic ketone groups as part of R1 or R2 per 100 recurring units.  An aromatic ketone group is defined as a carbonyl group linked to 2 carbon atoms at least one of which is a member of an aromatic ring.  R1 may be of formula <FORM:1083168/C3/2> <FORM:1083168/C3/3> <FORM:1083168/C3/4> or <FORM:1083168/C3/5> R2 may be of formula <FORM:1083168/C3/6> <FORM:1083168/C3/7> <FORM:1083168/C3/8> <FORM:1083168/C3/9> <FORM:1083168/C3/100> <FORM:1083168/C3/111> <FORM:1083168/C3/122> <FORM:1083168/C3/133> <FORM:1083168/C3/144> <FORM:1083168/C3/155> <FORM:1083168/C3/166> <FORM:1083168/C3/177> or <FORM:1083168/C3/188> where R7 and R9 are any divalent radicals. R1, R2, R7 and R9 may be substituted.  The composition may also contain a filler, e.g. Al dust, Al2O3 powder or Zn dust, a thermostabilizer, e.g. arsenic thioarsenate, copper quinolate, or arsenic pentoxide, a solvent, e.g. dimethyl acetamide, xylene, N-methylpyrrolidone or toluene and another resin, e.g. a phenoplast resin or an epoxy-resin.  Phenoplast resins specified are a butylated phenoplast and a novolak. Epoxy resins specified are: bisphenol type resins, <FORM:1083168/C3/199> and epoxy novolacs.  The composition may be produced by reacting the corresponding tetracarboxylic acid dianhydride with 15% excess of the corresponding diamine at up to 175 DEG  C. in an organic solvent for the reactants and optionally for the polymer. Anhydrides specified include those of benzophenone tetracarboxylic acid, diphenyl ether tetracarboxylic acid and diphenyl methane tetracarboxylic acid.  Diamines specified include hexamethylene diamine, bis(aminophenyl) methane, bis(aminophenyl) ether and bis(aminophenyl) ketone.  Reaction solvents specified include dimethyl acetamide and N - methyl pyrrolidone.  The polymer may be precipitated from the product by adding a non-solvent or the polyamide-acid composition may be cured to a cross-linked polyimide by heating at 50-200 DEG  C.  Curing may be in two stages: initially at 80-150 DEG  C. and then at 150-500 DEG C.ALSO:Adhesive coatings comprise mixtures of (A) a polyamide having end-groups of formula -NH-R2-NH2 and recurring units of formula:- <FORM:1083168/B1-B2/1> where R1 and R2 may vary from one structural unit to another and are aliphatic aromatic; carbocyclic or heterocyclic and (B) at least 15 mole % of a diamine of formula NH2-R2-NH2 the polymer containing at least 30 aromatic ketone groups per 100 recurring units.  An aromatic ketone group is defined as a carbonyl group linked to 2 carbon atoms at least one of which is a member of an aromatic ring.  On curing the mixture a cross-linked polyimide is formed.  Substrates specified are: aluminium alloys, stainless steel, cold rolled steel, magnesium, titanium, copper, brass, galvenized iron, glass, ceramics, quartz, silicone resins, and polytetrafluoroethylene. The polyimide coatings may be overcoated with epoxy-resins, silicone resins, phenolic resins, polyvinyl formal, acetal or butyral resins, polyurethanes, alkyds, polyamides, polyesters, melamine-formaldehyde resins, urea-formaldehyde resins, benzo-guanamine-formaldehyde resins and polytetrafluoroethylene.