Isg Technologies Inc.

Weirton Steel Corporation

Michael S Bailey

Mark Vincent Loen

John A Sinsel

Processes and apparatus for manufacturing an engineered-composite combining rigid flat-rolled sheet metal continuous-strip and selected polypropylene thermoplastics, which are formulated into dual polymeric coating layers for extrusion deposition, as distinct layers, on a single surface at a time, of continuous-strip, traveling in-line at ambient temperature. Steps for forming a uniform thickness of polymeric layers across strip width, and attraction to an activated metallic surface which provides enhanced adhesion. Solidification of the polymeric layers is augmented by strip temperature during continuous-in-line travel; final dual-surface finishing provides for complete bonding of the polymeric layers on both metallic surfaces.

Methods and apparatus for surface preparation and dual polymeric layer coating of continuous-strip flat-rolled sheet metal, and coated product

Method steps and apparatus combinations for continuous in-line polymeric coating of rigid corrosion-protected flat-rolled sheet metal continuous-strip substrate utilizing a thermoplastic polymeric material having adhesive characteristics, capable of molten thin-film extrusion for chemical-bonding with an activated-surface of the flat-rolled sheet metal substrate, and substantially-simultaneously bonding with a solid-film polymeric material, establishing a work-product embodiment with multiple-polymer-layers traveling with the single activated surface; and, on which the solid polymeric film is selected to provide strength, hardness and other desired surface mechanical properties which also provide for external surface coloration, design, weather-proofing, and fabricating capabilities. A second embodiment provides dual-surface multiple-polymeric layer coating carried on by activating and polymeric coating one surface, at a time, of rigid corrosion-protected flat-rolled sheet metal continuous strip substrate.

Extruded molten polymeric film bonding of solid polymeric film to flat-rolled sheet metal continuous strip

A process is provided for making a composite work article suitable for fabricating rigid sheet metal can components. A steel sheet having first and second surfaces is pre-treated to enhance reception and retention of a multi-layer polymer coating on the pre-treated first surface. The multi-layer polymer coating is melt extruded on the pre-treated first surface and beyond opposite lateral edges of the work article to establish overhang portions, then solidified. The multi-layer polymeric coating has a tie polymeric layer contacting the pre-treated first surface, and a finish-surface polymeric layer. The solidified overhang portions are trimmed, and the extruded multi-layer polymeric coating is subjected to finish-treatment, involving heating the extruded multi-layer polymeric coating at least to a melt temperature thereof, then cooling the multi-layer polymeric coating through glass-transition temperature thereof at a sufficiently rapid rate to establish amorphous non-directional characteristics in the polymeric coating.

Polymeric coating formulations and steel substrate composites

Engineered composite coated flat-rolled steel strip is produced in continuous line operations, in which flat-rolled steel strip, free of surface iron oxide, having a metallic corrosion-protective coating, is polymer coated in continuous-line operations in which a plurality of adherent thin-film layers of polymeric material are deposited on a strip surface. In a dual-surface polymeric coating embodiment, each surface is separately-pretreated for surface adhesion, solidified, and polymeric overhang is removed. Finish processing re-melts the polymer coating and rapidly cools that coating through glass-transition temperature to establish amorphous characteristics in the polymeric coating materials. An anhydride-modified polypropylene, first contacts the strip, an intermediate layer can include about fifteen to twenty five percent, by weight, polybutylene with the balance polypropylene; an outer surface polymeric layer includes about five to ten percent, by weight, polybutylene with the balance polypropylene.

Surface preparation and polymeric coating of continuous-strip flat-rolled steel and coated product

Flat-rolled steel strip, free of surface iron oxide, is provided with a corrosion-protection metallic coating on both surfaces, followed by continuous-line polymeric coating operations in which a single surface is pre-treated so as to activate that surface for adhesion of molten extruded thin-film polymeric material for in-line travel. Polymeric materials are formulated to provide maleic-anhydride modified polypropylene, which is melted and pressurized for extrusion as a molten thin-film tie-layer for first contacting that activated surface; and, thin-film intermediate and finish layers are each formulated to contain a selected percentage of polybutylene; which are extruded as molten films in overlaying relationship to said first contacting tie-layer. Polymeric finish-processing re-melts the polymeric materials; and, following a selected interval of in-line travel in that re-melted condition, rapidly cools those polymeric materials through glass-transition temperature so as to establish amorphous characteristics throughout said materials. End-usage product comprise flat-rolled mild steel can stock for fabricating one-piece drawn, and drawn and ironed, can bodies with interior polymeric coating and an exterior corrosive-protection metal coating, such as matte-finish electrolytic tin plate.

Growing community of inventors

Landenberg, PA, United States of America

Michael S Bailey