METHOD OF COATING A METALLIC SUBSTRATE WITH THERMOPLASTIC COATING MATERIAL

摘要

Method of coating a metallic substrate (1) with thermoplastic coating material, comprising a preheating the substrate in such as way that, just prior to coating, it is at a temperature between 70 DEG C and 150 DEG C, preferably between 100 DEG C and 130 DEG C in the case of a coating containing polypropene and between 80 and 110 DEG C in the case of a coating containing polyethene; coextrusion, in the first coating station of a sheet (6) comprising a polyolefin covering layer and a modified polyolefin adhesion layer; coating of the substrate (1) with a molten sheet in the presence of ozone by pressing it with the adhesion layer against the surface of the substrate; transportation of the strip (9) coated on one side to a second coating station and heating the strip so that, just before coating, the strip is at a temperature between 70 DEG C and 130 DEG C, preferably between 80 DEG C and 120 DEG C, if the coating layer applied in the first coating station is polypropene and between 80 and 110 DEG C if the coating layer applied at that point is polyethene; coating of the substrate with a molten sheet extruded in the second coating station by pressing it against the uncoated surface of the substrate, use being made of the presence of ozone; heating of the coated substrate so that it assumes a temperature which is above the melting point of the polyolefins applied; cooling of the coated substrate.