PREPARATION OF THERMOPLASTIC POLYESTER RESIN FOAM

摘要

PROBLEM TO BE SOLVED: To prevent unstableness of extrusion and also to stabilize the quality of a foam to be obtained, by supplying a resin melt properties adjusting agent in a prescribed quantity from an additive supply port after the water contained in resin is removed through a vent port of an extruder. SOLUTION: A vent port is provided in the middle of a barrel of an extruder and the water contained in resin is removed therethrough by reduced-pressure drawing. Then, a resin melt properties adjusting agent is supplied from an additive supply port provided separately in the middle of the barrel of the extruder and it is mixed and put in reaction. As for the melt properties adjusting agent, a compound having two or more anhydride groups in one molecule, such as a pyromellitic dianhydride or a benzophenone tetracarboxylic dianhydride, is used and a compounding amount thereof is made 0.1-5 pts.wt. to 100 pts.wt. of thermoplastic polyester resin in order to give melt viscoelasticity thereto. The melt viscosity of the thermoplastic polyester resin at a processing temperature thereof is made 100-10000Pa.s preferably.