Flexible metal clad laminates and methods of preparation thereof

A film comprising a thermosetting composition, the thermosetting composition comprises, based on the total weight of the thermosetting composition:

• a) a copolymer of (i) a diisoalkenylarene and (ii) a divinylarene containing m-divinylarene and p-divinylarene, in a mole ratio of (i) to (ii) of 15:1 to 1:15, the copolymer being present in an amount of 30-85 wt. %;
• b) a second polymer in an amount of 2-10 wt. %;
• c) a filler in an amount of 13-50 wt. %;
• and
• d) an optional additive in an amount up to 10 wt. %;
• wherein the film has:
• a thickness of 10 to 300 μm;
• a dielectric constant (Dk) of <3.5, measured at 10 GHz, according to ASTM D2520;
• a dissipation Factor (Df) of <0.005, measured at 10 GHz, according to ASTM D2520;
• and
• a coefficient of thermal expansion of <30 ppm/° C., as measured using TMA over a range of −50 to 300° C., according to ASTM E 228.
• a 90° peel strength to metal of >0.6 N/m performed according to IPC 650 2.4.19;
• a water uptake capacity of <0.5%, based on total weight of the film;
• and
• a tensile elongation of >10%, according to IPC-TM 650 2.4.19.