US Patent 11912819 Bifuran polyesters

Semicrystalline polyethylene-2,2′-bifuran-5,5′-dicarboxylate (PEBF) homopolyester or copolyester with up to 5 mole percent isophthalate or up to 2.7 mole percent terephthalate, based on the diacid component, or up to 2.5 mole percent 1,4-cyclohexanedimethanol (CHDM), based on the diol component, prepared by esterifying or transesterifying the diacid and the diol components with a catalyst including about 10 to about 50 ppm wt metal, and polycondensation, wherein the bifuran polyester has an intrinsic viscosity of at least 0.4 g/dL and a semicrystalline melting peak (Tm) with ΔHf equal to or greater than 5 J/g on the second heating ramp.