Biodegradable polyester, preparation process thereof and products comprising said polyester

Biodegradable aliphatic-aromatic polyester comprising units deriving from at least a diacid and at least a diol, said polyester having long chain branches, being essentially gel-free, and being characterized in the molten state by a Shear Viscosity, from 800 to 1,600 Pas measured according to the standard ASTM D-3835-90, at 180° C., a flow gradient γ=103.7 s−1 with a capillary D=1 mm, L/D=30;

• by a Thermal Stability Constant K of less than 1.5×10−4 measured according to the standard ASTM D-3835- Appendix at 180° C. a flow gradient γ=103.7 s−1 with a capillary D=1 mm, L/D=30;
• by a Melt Strength from 2 to 4.5 g and by a Breaking Stretching Ratio>30 measured according to the International Standard ISO 16790:2005 at 180° C., a flow gradient γ=103.7 s−1 with a capillary D=1 mm, L/D=30 and drawn with a constant acceleration of 12 mm/sec2 and with a drawing length of 110 mm, said polyester being obtainable through a process characterized by comprising the reactive extrusion of a polyester precursor comprising units deriving from at least a diacid and at least a diol, said polyester precursor being linear, having a MFI of 5-30 g/10 min at 190° C. and 2.16 kg and having a content of terminal unsaturations in quantities of 0.1-1% by moles, said reactive extrusion process being performed with the addition of a compound selected from peroxides, epoxides and carbodiimides.