Nitrogen Suppression of Oxidation of the Melt Curtain During Extrusion Coating

摘要

Article, substrate or film have been coated. In an embodiment, the coating may modify the properties of the article, substrate or film. One example of a coating is that of a heat-sealable film, i.e., a film which is capable of being bonded to itself, another film or another substrate with the application of heal and/or pressure. In this manner, the article, substrate or film can be sealed to form structures such as bags or other packaging materials. Laminates and single or multi-layer films are two packaging materials that can employ heat-sealable layers. Laminates may be made by coaling a substrate, for example, paper or film, with a heat-sealable layer by extrusion coating. Extrusion coating is a process whereby a polymer or blend of polymers is fed into an extruder hopper. In the hopper the polymer or blend may be melted and passed through a die to form a web. The web may be then extruded onto the substrate through a nip roll/chill roll interface, for example, so that the molten web is pressed onto the substrate. The substrate may be cooled by the chill roll and the wound up at a winder.