Extrusion-coated strip for rigid packagings

Abstract

The invention relates to a method for producing a coated aluminium strip, in which the aluminium strip is unwound from a coil and fed into a unilateral or bilateral extrusion coating arrangement, the aluminium strip is extrusion coated with a thermoplastic polymer and after being extrusion coated, the aluminium strip is reheated to a metal temperature above the melting point of the thermoplastic polymer. The object of providing a method for producing an aluminium strip by which an extrusion-coated aluminium strip can be produced which can be processed at high processing speeds in follow-on composite tools is achieved in that the unilateral or bilateral plastics material coating of the aluminium strip is textured, after being reheated, using rolls which have a superficial structure.

1 - 15 . (canceled) 
     
     
         16 . An aluminium strip with a unilateral or bilateral thermoplastic polymer layer extruded onto the aluminium strip, comprising:
 a plastics material coating having a surface, and;   wherein the surface of the plastics material coating of the aluminium strip has an isotropic texture applied after coating, preferably a texture of an EDT surface.   
     
     
         17 . The aluminium strip according to  claim 16 , wherein the roughness R a  of the textured surface of the thermoplastic polymer coating is from 0.02 μm to 10 μm. 
     
     
         18 . The aluminium strip according to  claim 16 , wherein the extrusion coating has a polypropylene layer or a polypropylene blend layer and optionally an adhesion-promoting layer. 
     
     
         19 . The aluminium strip according to  claim 16 , wherein the thickness of the extrusion coating of the aluminium strip is from 0.02 μm to 20 μm. 
     
     
         20 . The use of the aluminium strip according to  claim 16 , for producing rigid packagings, in particular can ends. 
     
     
         21 . The aluminium strip of  claim 16  produced by a method comprising the steps of
 unwinding an aluminium strip is from a coil; 
 feeding the aluminium strip into a unilateral or bilateral extrusion coating arrangement; 
 extrusion coating the aluminium strip with a thermoplastic polymer; and after being extrusion coated, reheating the aluminium strip to a metal temperature above the melting point of the thermoplastic polymer, wherein the unilateral or bilateral plastics material coating of the aluminium strip is textured, after being reheated, using rolls which have a superficial structure. 
 
     
     
         22 . The aluminium strip of  claim 21 , wherein the rolls used for texturing are tempered. 
     
     
         23 . The aluminium strip of  claim 21 , wherein the rolls used for texturing have an isotropic texture or an EDT superficial structure introduced using the electron discharge method. 
     
     
         24 . The aluminium strip of  claim 21 , wherein the roughness R a  of the plastics material coating after texturing by the rolls is from 0.02 μm to 10 μm. 
     
     
         25 . The aluminium strip of  claim 21 , wherein after texturing, the extrusion-coated aluminium strip is cooled using an air and/or water cooling means. 
     
     
         26 . The aluminium strip of  claim 21 , wherein the thickness of the plastics material coating is from 0.02 μm to 20 μm. 
     
     
         27 . The aluminium strip of  claim 21 , wherein a polypropylene of a polypropylene blend is used for the plastics material coating. 
     
     
         28 . The aluminium strip of  claim 21 , wherein before being unilaterally or bilaterally extrusion coated, the aluminium strip is subjected to cleaning, degreasing, pickling and a pretreatment by applying a conversion layer or is subjected to an anodising process. 
     
     
         29 . The aluminium strip of  claim 21 , wherein during extrusion coating, an adhesion-promoting layer is co-extruded in addition to the thermoplastic polymer coating. 
     
     
         30 . The aluminium strip of  claim 21 , wherein a packaging strip, in particular for beverage cans, is produced.