Process for the polymer coating of non-ferrous metal surfaces

摘要

The present invention relates to a method for coating a surface of a nonferrous metallic substrate, with a bilayer polymeric coating, said method comprising: 1) Subjecting the surface of a nonferrous metal object to a chemical washing; 2) Heating the article whose surface will be coated, to a temperature higher than the melting temperature of the selected polymer and lower than the ignition temperature thereof; 3) Apply the first layer, with a size of less than or equal to 20 mesh particle, constantly keeping the substrate temperature; 4) Applying a second layer of plastic coating on the first coating layer, after the first layer has adhered to the substrate surface, where the second layer can be the same or different polymer, with a particle size equal to or less 20 mesh; 5) Heating further the set of substrate and bilayer coating to a temperature higher than the selected at step 2, but lower than the ignition temperature of the coating and 6) Cooling the thus coated substrate to room temperature. The product obtained by the described process, provides a smooth, nonporous surface, a high adhesion of the coating to the substrate and covering all exposed to the chemical treatment of the first stage surface is ensured, so that the resulting coated substrate is suitable for use in the food industry.

主权项

1. A process for the covering with polymeric material of the surface of products manufactured of nonferrous metals, where the covering consists of a polymer bilayer; one first adhesive layer that produces an uniform jointless cover with high adherence to the substrate surface under treatment, and a second working layer, of a polymeric material same or different of the first layer, that provides desirable qualities to the coating, said process characterized by comprising the steps:
a).—Treat the nonferrous metal object surface, with a chemical washing, b).—Heat the metal object to a temperature over the melting temperature of the polymer selected for the first layer of the cover, but lower than the ignition temperature thereof, c).—Apply the first layer of the polymer cover, maintaining the substrate temperature constant; remove excess of the mixture, and allow the polymer to evenly distribute on the surface of the object until this first layer has adhered to the surface of the object, d).—Apply a second layer of the polymer cover over the first layer of the cover of the previous step; e).—Heat the assembly of the substrate and bilayer coating at a temperature between the melting temperature of the polymer selected for the layer, but lower than the ignition temperature thereof, allowing to flow over the surface and achieve a smooth surface finish and, f).—Cool the so coated substrate to room temperature.