Epoxy resin/cyannate ester copolymer with improved fire safety, mechanical properties and low dielectric loss enabled by 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphazephenanthrene-10-oxide and copper hydroxystannate

Epoxy resin/cyanate ester copolymer (EC) possesses the advantages of low dielectric constant and low dielectric loss, while the easy flammability of EC restricts its applications. The effect of 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphazephenanthrene-10-oxide (DQ) and copper hydroxystannate (CuHS) on the flame retardancy, smoke suppression, mechanical properties and thermal decomposition behavior of EC was studied. The EC composite containing 7 wt% DQ and 3 wt% CuHS (EC/7DQ3CuHS) passed the UL-94 V0 rating with a limiting oxygen index of 32.0% The peak heat release rate and total heat release of EC/7DQ3CuHS fell by 41.9% and 35.0% respectively, compared with those of pure EC. The total smoke release of EC/7DQ3CuHS was reduced by 36.0% in comparison with that of the EC composite containing 10 wt% DQ. The tensile and impact strengths of the EC composite with 9 wt% DQ and 1 wt% CuHS increased by 16.9% and 19.2%, respectively in contrast with pure EC. The dielectric constant and dielectric loss of the EC composites maintained at relative low values. The as-prepared EC composites have application prospect in electronic packaging industry.