Notes

In the coating of plastic onto aluminum foil or different steel foil it has been found that the coating can happen by means of a traditional extrusion process which suggests the extrusion of a melted plastic mass beneath excessive strain through a slender, slotlike opening to form a skinny movie which is precipitated onto the metallic foil layer, whereupon the metallic foil coated with the plastic materials is launched between compressive rollers, which on the similar time have a cooling impact. It is kind of attainable in itself to supply by this technique a relatively good adhesion between the coated plastic layer and the metallic foil layer, which, moreover, could be combined prematurely with the stated base paper layer, however in such a case the extrusion of plastic material must be carried out at a really excessive temperature, that is to say at a temperature which on the extrusion of polyethylene exceeds 300° C. At this comparatively excessive temperature the plastic materials is uncovered to a surface oxidation which unfortunately has the result that the plastic layer can not be heat-sealed as easily as if it had not been oxidized. As it's crucial that the within layer of the packing laminate should be heat-sealable, since otherwise tight packages can't be obtained, it is needed within the coating of the plastic materials onto the metallic foil layer to use an extrusion temperature which is so low that the plastic materials just isn't oxidized. Approximately and in the alternative of the extrusion temperature numerous outdoors elements should be taken into account, such as e.g., the plastic quality, the room temperature, the rate of extrusion and so forth.
The packing laminate of the kind concerned here moreover incessantly contains a base layer of some kind, in particular paper of carton, and also linings of thermoplastic material, which linings on the one hand are intended to protect the completed packages from moisture and wetness, then again have the thing of constructing the packing laminate heat-sealable and finally have the item of joining together the fabric layer introduced into the laminate. The side of the packing laminate which shall be turned toward the within of the finished package is generally covered with a layer of thermoplastic material, e.g., polyethylene, and the fabric layer following that is usually constituted of a steel foil layer which then in its turn is fastened to a supporting paper layer with the assistance of an intermediate thermoplastic coat of e.g., polyethylene. Finally, the surface of the packing laminate, that's to say the facet of the packing laminate which can type the outside of the package, will be supplied with a thermoplastic coat of e.g., polyethylene, which has as its object the safety of the bottom layer of paper and the prevention of the absorption of moisture by the mentioned layer. It could additionally be appropriate in certain instances to heat the steel foil layer to a temperature which appreciably exceeds 100° C., e.g., 150° - 200° C., however to forestall in this case the plastic layer from melting down it might be acceptable to apply a cooling fuel, e.g., a chilly air against the outside of the plastic layer three. Naturally it's potential throughout the framework of the idea of the invention to arrange the coils, via which the electromagnetic field is generated, in some other method than that shown here, but sensible experiments have advised that the embodiment described right here is very appropriate, no much less than within the therapy of comparatively flexible material webs. It could after all be applicable generally to chill the coil windings, that's to say the bars 6 which may readily be carried out by providing the bars 6 with bores via which a cooling liquid can be made to flow into.
Finally a second pair of compression rollers is designated 10 and a journal roller for the finished packing materials is designated 11. The current invention issues a way for the manufacture of laminated packing materials containing at least one layer of a steel foil, e.g., aluminum foil, and a layer of plastic material applied to the stated metal foil. food extruder issues an apparatus for the belief of the method for the manufacture of laminated packing material. Modern packages, that are manufactured from an online of packing laminate or from sheet of laminated material, frequently comprise a layer of a steel foil, particularly aluminum foil, which lends the packing laminate excellent tightness characteristics in opposition to gases and furthermore provides very effective gentle protection.
As mentioned above, a worse adhesion is obtained between plastic layer and steel foil layer if the extrusion temperature is low, which implies that the plastic layer within the finished package could delaminate and thus in precept form a plastic bag contained in the package deal which is free from the metallic foil layer. This of course isn't desirable, nevertheless it must be the thing to obtain a non-oxidized internal plastic layer as nicely as good adhesion between plastic layer and steel foil, and so as to achieve this it was necessary to just accept a compromise between sealability and lamination energy and accordingly the lamination temperature had to be adjusted and maintained very precisely, which can trigger nice difficulties. food extruder is characterized additional in that the device for the execution of the stated second operational stage consists of one of several coils preferably organized in one plane, that are connectable to a supply of current which may deliver an a.c. In the FIGURE numeral 1 refers to a laminate web the upward turned layer of which consists of a steel foil layer or a metal foil web. Furthermore a pair of compression rollers cooperating with one another is marked four and a pair of information rollers 5. A high frequency present supply is designated 9 and the feed lines from the supply of present 9 to the bars 6 are marked eight.
Website: http://erickaqaf28395.tblogz.com/the-2-minute-rule-for-food-machine-18568567