Laminate for electronic materials
View Patent ↗This invention relates to a laminate which is excellent in heat resistance after moisture absorption required in a lead-free solder joint, and is suitable for use in flexible printed wiring boards or HDD suspensions. The laminate for electronic materials of this invention is constituted of a conductor layer and an insulating resin layer having a polyimide-based resin layer (A) and a polyimide-based resin layer (B). The polyimide-based resin layer (A) constituting the insulating layer includes a polyimide-based resin obtained by reacting a diamine containing 40 mol % or more of 4,4′-diamino-2,2′-dimethylbiphenyl with an aromatic tetracarboxylic acid, and the polyimide-based resin layer (B) includes a polyimide-based resin containing 80 mol % or more of a structural unit generated from bis(4-aminophenoxy)benzene or 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and pyromellitic acid, benzophenonetetracarboxylic acid, diphenylsulfonetetracarboxylic acid or biphenyltetracarboxylic acid.
1. A laminate comprising a conductor layer and an insulating resin layer that is formed of plural polyimide-based resin layers,
wherein the insulating resin layer has at least two layers: (1) a polyimide-based resin layer (A) obtained by reacting a diamine compound containing 40 mol % or more of 4,4′-diamino-2,2′-dimethylbiphenyl with a tetracarboxylic acid compound; and (2) a polyimide-based resin layer (B) containing 80 mol % or more of a polyimide structural unit represented by the following general formula (1):
wherein, in formula (1), R 1 is at least one kind of group selected from the group consisting of groups represented by the following formulae (2),
and groups represented by the following formulae (3)
R 2 is at least one kind of group selected from group consisting of groups represented by the following formulae (4),
and groups represented by the following formulae (5)
wherein, in formula (4), X shows at least one kind selected from the group consisting of SO 2 , CO, and single bond, and
wherein the polyimide-based resin layer (B) is in contact with the conductor layer.
2. A laminate according to claim 1 , wherein the insulating resin layer comprises a three-layered structure having the polyimide-based resin layer (B), the polyimide-based resin layer (A) and the polyimide-based resin layer (B) that are laminated successively.
3. A laminate according to claim 1 , wherein the polyimide-based resin layer (A) comprises a polyimide-based resin containing 40 mol % or more of at least one structural unit selected from the group consisting of structural unit represented by the following formulae (6):
and structural unit represented by the following formulae (7):
4. A laminate according to claim 1 , wherein the insulating resin layer has, on both sides thereof, conductor layers.
5. A laminate according to claim 1 , wherein the insulating resin layer comprises a two-layered structure having the polyimide-based resin layer (B) and the polyimide-based resin layer (A) that are laminated successively.
6. A laminate according to claim 1 , wherein the insulating resin layer comprises a three-layered structure having the polyimide-based resin layer (B), the polyimide-based resin layer (A) and the polyimide-based resin layer (B) that are laminated successively.
7. A laminate according to claim 1 , wherein the insulating resin layer consists of the polyimide-based resin layer (A) and the polyimide-based resin layer (B).