Patent ID: 11905372
Assignee: PI ADVANCED MATERIALS CO., LTD.
Field: Surface technology, coating (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 2:
3. A method for manufacturing a polyimide film, the method comprising the steps of:
(a) polymerizing a first dianhydride component and a first diamine component in an organic solvent to prepare a first polyamic acid;
(b) polymerizing a second dianhydride component and a second diamine component in an organic solvent to prepare a second polyamic acid;
(c) polymerizing the first polyamic acid and the second polyamic acid in an organic solvent to prepare a third polyamic acid; and
(d) forming a precursor composition containing the third polyamic acid into a film on a support, followed by imidization,
wherein the first polyamic acid comprises a dianhydride component consisting of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride, and a diamine component consisting of p-phenylenediamine, and
the second polyamic acid comprises a dianhydride consisting of pyromellitic dianhydride and a diamine component consisting of m-tolidine,
Wherein the 3,3′,4,4′-benzophenonetetracarboxylic dianhydride is used at a content of 15% by mole to 35% by mole and the 3,3′,4,4′-biphenyltetracarboxylic dianhydride is used at a content of 35% by mole to 75% by mole, based on a total of 100% by mole of the first dianhydride component and the second dianhydride component,
wherein the m-tolidine is used at a content of 20% by mole to 40% by mole and the p-phenylenediamine is used at a content of 60% by mole to 80% by mole, based on a total of 100% by mole of the first diamine component and the second diamine component,
wherein a glass transition temperature (Tg) of 320° C. or higher, a moisture absorption rate measured by the ASTM D570 test method is 0.4 wt % or less, and a dielectric dissipation factor (Df) of 0.004 or less at a frequency of 10 GHz.