| 摘要 |
A process for the production of PET foams which comprises the extrusion of a mixture of PET, epoxy resin, catalyst consisting of imidazole, derivatives of imidazole or mixtures thereof plus a blowing agent, wherein the homopolymerization reaction of the epoxy phase is effected in the extruder, upstream of the introduction of the blowing agent. Compared to the methods of the known art, the process of the invention offers the advantage of providing a stable PET foam, in which the structure of the polymer chains is kept unaltered. The system therefore has viscoelasticity characteristics which allow the PET/epoxy homopolymer to receive the expanding action of the blowing agent, as far as the innermost and deepest layers of foam also having a significant thickness. |
