Patent ID: 7288618

Claim:
A thermoplastic biodegradable aliphatic polyester of the diacid/diol type comprising the following monomers: a) at least one aliphatic dicarboxylic acid, or esters thereof, with C 9 -C 13 atoms; b) at least one aliphatic or cycloaliphatic diol, with 2-20 C atoms; c) at least one at least trifunctional molecule wherein c), based on the sum of the moles of the aliphatic dicarboxylic acid and of said at least trifunctional molecule, is comprised in the range from 0.05% to, as upper limit, a value according to the following formula % ⁢ ⁢ P = 0 , 0015 · N 3 f · η inh which is applicable for η inh >0,6 dl/g and wherein % P=percentage in moles with respect to the sum of the moles of said at least trifunctional molecule and dicarboylic acids moles N=average number of C atoms of the repeating diacid/diol unit in the main polymeric chain η inh =inherent viscosity f=number of reactive moieties in the at least trifunctional molecule, and further comprising a concentration of an unsaturated acid originating from vegetable oils of at least 0.5% and lower than 15% in moles based on the sum of the moles of unsaturated acid and the moles of the aliphatic dicarboxylic acid or esters thereof; and wherein said biodegradable aliphatic polyester has a gel fraction lower than 2.0% (w/w) with respect to the polyester.