Composition of polyimide and sterically-hindered hydrophobic epoxy

A screen-printable composition comprising a polyimide component, a sterically hindered hydrophobic epoxy and an organic solvent;

• wherein the polyimide component is represented by a polyimide having a repeat unit represented the formula;
• wherein X can be equal to SO2 or C(CF3)2, C(CF3)phenyl, C(CF3)CF2CF3, or C(CF2CF3)phenyl, and combinations thereof, and
• wherein Y is derived from a diamine component comprising from between and including any two of the following numbers, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 mole percent of a diamine selected from the group consisting of, 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6F-AP), 2,4-diaminophenol, 2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and 2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane;
• wherein the sterically hindered epoxy is represented by the following formula,
• wherein Z is an alkyl, alkoxy, phenyl, phenoxy, halogen, or combinations thereof;
• wherein Y is either a covalent bond, oxygen, sulfur, methylene, fluorenylidene, ethylidene, sulfonyl, cyclohexylidene, 1-phenylethylidene, or C(CH3)2, C(CF3)2;
• and
• wherein m is an integer between and including any two of the following numbers, 0, 1, 2, 3, 4 and 5;
• and
• wherein the organic solvent is selected from the group consisting of dibasic acid esters, propyleneglycol diacetate (PGDA), propylene glycol phenyl ether and mixtures of these, said composition further comprising a sterically hindered phenol represented by the following formula,
• wherein Z is an alkyl, alkoxy, phenyl, phenoxy, halogen or combinations thereof,
• wherein Y is a covalent bond, oxygen, sulfur, methylene, fluorenylidene, ethylidene, sulfonyl, cyclohexylidene, 1-phenylethylidene, C(CH3)2, or C(CF3)2, and,
• wherein m is an integer between and including any two of the following numbers 0, 1, 2, 3, 4 and 5.