| abstract |
This apparatus comprises a roller 28, a die head 12 comprising flow conduits 14, 16, 18, 20 communicating with extruders, a die holder 24 contiguous to the surface 30 of the roller, a die assembly 22 whose cylindrical surface 26 follows this surface 30 and which comprises two grooved die elements 32, 38, having grooved surfaces 34, 36, 40, 42 which constitute preforming passages 50, 54, 56, 58 extending from the conduits flow to orifices in the cylindrical surface of the die assembly, a downstream die plate 46 disposed between a die element 38 and the die holder 24, an upstream die plate 44 disposed between the elements of grooved die 32, 38, the grooved surfaces of the die elements coming into abutment contact against the downstream and upstream die plates, forming at least some of the preforming passages, and recessed parts provided on edges s 68, 76, 64, 72 of the upstream and downstream die plates and of at least one of the die elements, these recessed parts serving to give the layers their shape and to guide them after their application on the surface of the roller so as to form the single coextruded product. |