Production method of polyolefin PP/PVDC/polyolefin PE multilayer compounded tube

The invention relates to a polyolefin PP, PVDC and polyolefin PE multilayer compounded tube, effectively solving the problems that plastic tubes have the defects of toxity, low strength, weak toughness, weak impact resistance, high cost and complicated processing. The method comprises the following steps: respectively extruding a polyolefin PP outer layer, a PVDC intermediate layer and a polyolefin PE inner layer by an extruder and then heating, extruding a compounded tube by the same extruding port mould, wherein the compounded tube is formed by co-extruding a plurality of layers and has tightly combined adjacent layers and at least comprises the polyolefin PP outer layer the PVDC intermediate layer and the polyolefin PE inner layer, and sectionally heating the polyolefin PP outer layer and the polyolefin PE inner layer in a machine barrel zone and a die head zone of the extruder; sectionally heating the PVDC intermediate layer in the machine barrel zone and the die head zone; and carrying out vacuum sizing on the combined compounded tube, placing the sized compounded tube in water at 18-23 DEG C for secondary cooling, and printing, drawing and cutting the product in sizing to obtain the polyolefin PP, PVDC and polyolefin PE multilayer compounded tube. The polyolefin PP, PVDC and polyolefin PE multilayer compounded tube has no toxicity and side effects, high cost performance, simple processing, high strength, favorable toughness and strong impact resistance and is an innovation on the tubes.