THERMOPLASTIC COMPOSITE PIPE WITH MULTILAYER INTERMEDIATE LAYER Russian patent published in 2020 - IPC F16L9/128 B29C70/02 B32B1/08 

FIELD: machine building.

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 fibres in a matrix comprising thermoplastic polymer B, wherein polymer A and polymer B are different; c) application of film or composite material, which is obtained at stage d) and consists of film and tape provided at stage b) on tubular shell with melting of outer surface of shell and contact surface of film either beforehand, or simultaneously, or afterwards. Stage d) comprises application of tape provided at stage b) on external surface of film with melting of external surface of applied film and contact surface of tape either beforehand, or simultaneously, or afterwards. At that, surface of film, which is brought into contact with shell, consists of moulding mass containing polymer A in amount of at least 30 % by weight, and wherein the opposite surface of the film consists of a moulding mass containing polymer B in an amount of at least 30 % by weight. 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.

13 cl