Package encapsulant compositions for use in electronic devices

A composition comprising a maleimide compound and a curing initiator selected from the group consisting of a free-radical initiator, a photoinitiator, and a combination of those, the maleimide compound having the formula [M—Zm]n—K in which m is 0 or 1 and n is 1-6, and

• (a) M is a maleimide moiety having the structure
• 44
• in which R1 is H or an alkyl having 1 to 5 carbon atoms;
• (b) K is an aromatic group selected from group of aromatic groups having the structures:
• 45
• 46
• in which p is 1 to 100;
• 47
• in which p is 1 to 100;
• 48
• in which R5, R6, and R7 are a linear or branched chain alkyl, alkyloxy, alkyl amine, alkyl sulfide, alkylene, alkyleneoxy, alkylene amine, alkylene sulfide, aryl, aryloxy, or aryl sulfide species, which may contain saturated or unsaturated cyclic or heterocyclic substituents pendant from the chain or as part of the backbone in the chain, and in which any heteratom present may or may not be directly attached to the aromatic ring;
• or R5, R6, and R7 are a siloxane having the structure —(CR12)e—[SiR42—O]f—SiR42—(CH3)g— in which the R1 substituent is H or an alkyl group having 1 to 5 carbon atoms and the R4 substituent independently for each position is an alkyl group having 1 to 5 carbon atoms or an aryl group, and e is 1 to 10 and f is 1 to 50;
• 49
• 50
• (c) Z is a linear or branched chain alkyl, alkyloxy, alkyl amine, alkyl sulfide, alkylene, alkyleneoxy, alkylene amine, alkylene sulfide, aryl, aryloxy, or aryl sulfide species, which may contain saturated or unsaturated cyclic or heterocyclic substituents pendant from the chain or as part of the chain, and in which any heteratom present may or may not be directly attached to K.

A composition comprising a vinyl compound and a curing initiator selected from the group consisting of a free-radical initiator, a photoinitiator, and a combination of those, the vinyl compound having the formula

• 58
• in which m is 0 or and n is 1-6;
• and
• (a) R1 and R2 are H or an alkyl group having 1 to 5 carbon atoms, or together form a 5 to 9 membered ring with the carbons forming the vinyl group;
• (b) B is C, S, N, O, C(O), C(O)NH or C(O)N(R8), in which R8 is an alkyl group having 1 to 5 carbon atoms;
• (c) X is an aromatic group selected from the group of aromatic groups having the structures:
• 59
• (d) Q is a linear or branched chain alkyl, alkyloxy, alkyl amine, alkyl sulfide, alkylene, alkyleneoxy, alkylene amine, alkylene sulfide, aryl, aryloxy, or aryl sulfide species, which may contain saturated or unsaturated cyclic or heterocyclic substituents pendant from the chain or as part of the chain, and in which any heteratom present may or may not be directly attached to X.

A composition comprising a vinyl compound and a curing initiator selected from the group consisting of a free-radical initiator, a photoinitiator, and a combination of those, the vinyl compound having the formula

• 64
• in which m is 0 or 1 and n is 1-6;
• and
• (a) R1 and R2 are H or an alkyl group having 1 to 5 carbon atoms, or together form a 5 to 9 membered ring with the carbons forming the vinyl group;
• (b) B is C, S, N, O, C(O), C(O)NH or C(O)N(R8), in which R8 is an alkyl group having 1 to 5 carbon atoms;
• (c) K is an aromatic group selected from the group of aromatic groups having the structures:
• 65
• in which p is 1 to 100;
• 66
• in which p is 1 to 100;
• 67
• in which R5, R6, and R7 are a linear or branched chain alkyl, alkyloxy, alkyl amine, alkyl sulfide, alkylene, alkyleneoxy, alkylene amine, alkylene sulfide, aryl, aryloxy, or aryl sulfide species, which may contain saturated or unsaturated cyclic or heterocyclic substituents pendant from the chain or as part of the backbone in the chain, and in which any heteratom present may or may not be directly attached to the aromatic ring;
• or
• R5, R6, and R7 are a siloxane having the structure —(CR12)e—[SiR42—O]f—SiR42—(CH3)g— in which the R1 substituent is H or an alkyl group having 1 to 5 carbon atoms and the R4 substituent independently for each position is an alkyl group having I to 5 carbon atoms or an aryl group, and e is 1 to 10 and f is 1 to 50;
• 68
• (d) Z is a linear or branched chain alkyl, alkyloxy, alkyl amine, alkyl sulfide, alkylene, alkyleneoxy, alkylene amine, alkylene sulfide, aryl, aryloxy, or aryl sulfide species, which may contain saturated or unsaturated cyclic or heterocyclic substituents pendant from the chain or as part of the chain, and in which any heteratom present may or may not be directly attached to X.