Polylactic acid-based foam and its production process

The invention relates to a flexible PLA foam containing lens-like foam cells, where the aspect ratio (AR) of the lens-like foam cells of polylactic acid ( PLA) foam is between 0.1 and 0.9, the aspect ratio is the ratio between the smallest and largest diameters of the foam cell perpendicular to each other, furthermore flexible is understood to mean that on the application of a stretching force said flexible polylactic acid (PLA) foam stretches by more than 10% in the direction of the force, then when the stretching force is eliminated the foam returns to a status approximately the same as that before the stretching was performed with the stipulation that the permanent deformation within one cycle does not exceed 1%. Furthermore the invention also relates to a method for the production of the flexible PLA foam, which method includes the following steps: i) foaming of PLA; ii) the PLA is stretched uniaxially while the foam cells are forming; then following this iii) the foam stretched according to step ii) is left to relax.