Abstract: The method ensures that the core of thermoplastic material of the product is completely enveloped by a continuous covering formed by at least one sheet of a flexible material. Equipment for carrying out the method comprises an extruder 7 for delivering the thermoplastic material in a pasty state and in the form of a rod 16-18 having a regular section, means 20 for unrolling under this rod a sheet 19 of a flexible material, means 34 and 41 for completely enveloping said rod with said flexible material, and means for pulling on said sheet of flexible material and conveying the rod to calendering rolls 43 and 44, and means 46 for forming and means 47 for cutting to the desired length said rod which is thus completely enveloped by said sheet of flexible material. This equipment is applicable to the manufacture of shapes and plates for in particular the packaging and transportation of products.