METHOD OF PREPARING OF POLYIMIDE ANTIADHESION COATING Russian patent published in 1994 - IPC

FIELD: high-molecular compounds. SUBSTANCE: polyimide antiadhesion coating is prepared by application on metallic backing the solution in amide solvent - product of interaction of 4,H₂N-A-NH₂-diaminotriphenylamine (I) or its mixture with at least one of diamine of formula (II) SO₂Ph-O-, where A - meta-Ph-, -Ph-Z-Ph-, where Z is -O-, para-O-Ph-O-, meta-O-Ph-O-, -O-, -O-Ph-, = , =O=(CO₂)=Ph-X-Ph=(CO₂)=0, at molar ratio (I):(II) (0.65-0.90): (0.35-0.10), with dianhydride of formula -SO₂- (III), where X - -CO-, para-CO-Ph-CO-, meta-CO-Ph-CO-, -O-Ph-CO-Ph-O-, -O-Ph-SO₂-Ph-O-, O=(CO)₂=h-Y-Ph=(CO)₂=O, or its mixture with at least one of dianhydrides of formula σ (IV), where Y is -O-, para-O-Ph-O-, meta-O-Ph-O-, X ≠ Y - bond or X, being X does not equal with Y, at molar ratio (III):(IV) = (0.50-0.90): (0.50-0.10). Solution is kept preliminary at 20-90 C from 30 min to 5 days. At keeping at least one organic compound can be added additionally to the solution which is taken from the group of aromatic hydrocarbons, tertiary aliphatic amines, derivatives of aliphatic carboxylic acids, imidazoles. At addition of a mixture of acetic anhydride with triethylamine their molar ratio is (0.6-0.8):(0.8-1.8), respectively, at 1.0 mole of initial diamine. Food forms and sheets made of aluminium alloys, steel or titanium are used as backings. Backing with applied solution layer is subjected for thermal treatment at step temperature increase and heating at the last stage at 350-400 C. Porousless coating prepared shows high adhesion to metallic backing, heat- and thermal stability and mechanical strength to acid media and oils. EFFECT: enhanced quality of coating. 4 cl, 1 tbl