THERMOPLASTIC COMPOSITE PIPE WITH MULTILAYER INTERMEDIATE LAYER Russian patent published in 2019 - IPC F16L9/128 B29C70/02 B32B1/08 

FIELD: physics.

SUBSTANCE: group of inventions relates to production of multilayer thermoplastic composite pipes. Method of producing a thermoplastic composite pipe involves the following steps: a) providing a tubular shell having a wall comprising a thermoplastic polymer A in an area of the outer surface; b) providing a tape comprising reinforcing fibers in a matrix comprising a thermoplastic polymer B; c) providing a tape containing reinforcing fibers in a matrix containing thermoplastic polymer C. At that, polymer A and polymer B are identical or different, and polymer B and polymer C are different. Method also includes steps of: d) applying the tape provided at step b) to the tubular shell by welding; e) optionally cohesive connection of additional tape interlayers of the same type with a tape interlayer deposited at step d); f) applying a first film or composite material, which is obtained at step g) and consists of a first film and tape, provided at step c), on a first layer of composite material thus formed, with fusion of the outer surface of the first composite layer and a contact surface of the first film, or preliminary, either simultaneously, or thereafter; g) applying the tape provided at step c) to the outer surface of the first film with melting of the outer surface of the applied first film and the contact surface of the tape either preliminarily, or simultaneously, or thereafter; h) optionally cohesive connection of additional tape interlayers of the same type with tape interlayer deposited at step g). Second composite layer is obtained at steps g) and optionally h). At step i), optionally, an external coating layer consisting of a polymer material is optionally applied. Surface of first film, which is brought into contact with first composite layer, consists of molding mass containing polymer B in amount of at least 30 wt. %, and opposite surface of first film consists of molding mass containing polymer C in amount of at least at least 30 wt. %. Formation of composite material between identical polymers at key stage of method leads to achievement of better quality of adhesion.

EFFECT: pipe thus obtained is particularly suitable for oil or gas production when used in open sea.

15 cl