Abstract: The design of post coextrusion die for sealing strip in the plastic door and window was introduced. Using gradient pressurized runner, installing preheating block to extend the heating distance, and dot location by screws were discussed. Using gradient pressurized runner effectively ensured the extrusion pressure. Installing preheating block prolonged the heating time for the bonding position, which could improve the bonding strength. Dot location by screws decreased the extrusion resistance, and effectively improved the extrusion speed. Production practices proved that the coextrusion die was simple for operation, exact for location, solved the problems of the plastic profile location, and improved the bond strength of sealing strip.

Key words: post co-extrusion, extrusion die, sealing strip, plastic door and window