Method and equipment for producing steel-plastics composite tube with two layers of polymer layer

Abstract

A method for preparing the composite steel-plastics pipe with two polymer layers includes such steps as providing steel plate or steel band with holes, longitudinal curving or spiral rolling, welding to become a cylindrical metal skeleton, using an extruder to extrude out the fused polymer and make it to pass through the holes for wrapping the metal skeleton to form pipe wall, using another extruder to extrude out the fused polymer but make it not to pass through holes to form a polymer layer on formed pipe wall, and cooling. Its apparatus is also disclosed.

Description

Technical field: [0001] The invention relates to a production method of a steel-plastic composite pipe, in particular to a method in which the molten polymer extruded by an extruder passes through a cylindrical metal skeleton with holes to form a cladding pipe wall of the metal skeleton, and then extruded and compounded. A production method and device for forming the outer layer (or inner layer) of a steel-plastic composite pipe. Background technique: [0002] There are currently three methods and devices for the production technology of using a metal skeleton with holes as a reinforcement, extruding a composite polymer material on the skeleton as a continuum to wrap the skeleton to form a steel-plastic composite pipe: the first Such as British Patent GB2255, 148A92.10.28, Chinese Patent Application No. 99112221.6, 99232026.7, these disclosed technical solutions are to use the steel plate with holes to curl into a cylindrical shape longitudinally and weld it into a cylindric...

AI Technical Summary

Problems solved by technology

[0005] The production method of the steel-plastic composite pipe with two polymer layers of the present invention comprises bending the steel plate or steel strip with holes longitudinally or spirally winding and welding it into a cylindrical metal skeleton, or winding warp steel wires with latitudinal steel wires The cylindrical frame is welded, and at least two extruders are used, and the molten polymer extruded by one of the extruders passes through the flow channel of the extrusion die, the molding cavity and the core mold to pass through the cylindrical metal frame with holes , the skeleton is covered to form the pipe wall, and the molten polymer extruded by another extruder will pass through the flow channel of the extrusion die, the molding cavity and the core film without passing through the cylindrical metal skeleton. The inner layer or outer layer of the formed pipe wall is compounded with a polymer layer, and the pipe is cooled and shaped to produce a steel-plastic composite pipe with a two-layer polymer layer with a cylindrical reinforced metal skeleton, using at least two The extruder can produce a steel-plastic composite pipe with two types of performance plastic layer pipe wall, one of which extrudes a polymer with a polar group (such as a graft-modified polymer with a carboxyl or hydroxyl group) Or carbonyl polar group or polar polyethylene or polypropylene or silane crosslinking (or crosslinkable) polymer with polar group) through the flow channel of the extrusion die and the molding cavity and core mold Then pass through the cylindrical metal skeleton with holes, and wrap the skeleton to form the pipe wall, which solves the technical problem that the interface between the metal and polyethylene is not easy to be firmly bonded and combined into one. Another extruder subsequently extrudes the melt polymerization Without passing through the cylindrical metal skeleton, a polymer layer is compounded on the inner or outer layer of the formed pipe wall. This layer of polymer can be ordinary polyethylene (HDPE) or polypropylene (PP) ) or non-crosslinked heat-resistant polyethylene (PE-RT)

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