| abstract |
An aliphatic polyester resin having a λ value representing the magnitude of non-linearity of elongational viscosity of 1.5 to 8.0, said λ value being defined by the following formula (1): λ = λ 1 /λ 0 wherein λ 0 denotes the elongational viscosity at the transition point and λ 1 denotes the elongational viscosity when strain become twice that of a transition point, said transition point meaning a point between a linear region, i.e., the infinitesimal-deformation region, and a non-linear region, i. e., the large-deformation region. According to the present invention, an aliphatic polyester resin having excellent formability and forming stability as well as good biodegradability is provided. |