High-barrier multilayer composite thermoplastic plastic tube and production method thereof

The invention provides a composite thermoplastic plastic tube. The composite thermoplastic plastic tube sequentially comprises an outer barrier layer, a middle layer and an inner barrier layer from outside to inside. The invention also provides a production method of the composite thermoplastic plastic tube. The method comprises the following steps: respectively extruding the outer barrier layer, the middle layer and the inner barrier layer from three asymmetrically distributed plastic extruding machines, carrying out extruding fusion on the layers in a multilayer co-extrusion die to form one body, and cooling to obtain the composite thermoplastic plastic tube sequentially comprising the outer barrier layer, the middle layer and the inner barrier layer from outside to inside; and printing codes, and cutting. An experiment determination result shows that the CH4 penetration coefficient of the composite thermoplastic plastic tube is four orders of magnitude lower than the penetration coefficient of high density polyethylene (HDPE), and so the composite thermoplastic plastic tube has an excellent gas barrier performance.