RU204558U1 - COMPOSITE PIPE - Google Patents

Abstract

The utility model relates to pipeline technology, in particular to multilayer composite thermoplastic pipes with fiber reinforcement, manufactured by extrusion, or molding, and / or winding, used in the oil and gas industry, used for the transportation of gaseous and liquid-like substances, in the installation of gas and oil wells and for repair and start-up operations, for pipeline systems of water supply, heating, gas supply, compressed air supply systems, technological pipelines of ships and railway rolling stock, fire-fighting water supply systems. A composite pipe consists of an inner thermoplastic polymer pipe, a surrounding composite material consisting of a thermoplastic polymer composite material and unidirectional continuous reinforcing fibers, and an outer polymer sheath. The inner tube, composite material and outer polymer jacket are smoothly fused to each other by heating. The composite material contains elastic interlayers of thermoplastic polymer material, the modulus of elasticity of which is 20 ... 3600 MPa less than the modulus of elasticity of the thermoplastic polymer of the composite material. The elastic layer is heat-fused to the composite material. EFFECT: increased fracture toughness (fracture toughness) and flexibility of composite thermoplastic pipes. 14 p.p. f-ly, 2 dwg.

Description

FIELD OF TECHNOLOGY

The utility model relates to pipeline technology, in particular, to multilayer composite thermoplastic pipes with fiber reinforcement, manufactured by extrusion, or molding, and / or winding, used in the oil and gas industry, used for the transportation of gaseous and liquid-like substances, in the device of gas and oil wells, and for workover and tripping operations.

Other areas of application include: transportation of process gases, liquids, media and suspensions, pipeline systems for water supply, heating, gas supply, compressed air supply systems, process pipelines of ships and railway rolling stock, fire-fighting water supply systems.

LEVEL OF TECHNOLOGY

Well-known steel pipes are used in the operation of gas and oil fields, for the transportation of gaseous and liquid substances, as well as for repair and lifting operations.

During operation, steel pipes are exposed to internal stresses arising in the body of the pipes from various power loads, for example, the internal pressure of the transported medium and its own weight. The effect of internal stresses is enhanced by corrosive processes under the influence of aggressive components in the produced fluids (a mixture of oil, associated gas, formation water, hydrogen sulfide, carbon dioxide, etc.) or formation or river water injected into oil-containing formations. The action of force loads and corrosion processes on pipe metal is often counter-directional, which determines the appropriate nature of measures aimed at increasing the durability and reliability of pipes.

For example, for the perception of large loads from internal pressure and weight of pipes, it is necessary to increase the strength characteristics of pipes (yield strength, ultimate strength), which causes a simultaneous increase in the hardness of the metal. However, an increase in the hardness of the metal leads to an increase in brittleness, and a significant decrease in its toughness to fracture, resistance to corrosion processes by the mechanism of hydrogen sulfide cracking.

Significant roughness of the inner surface, due to the technology of manufacturing hot-rolled pipes, initiates the processes of asphalt-wax deposits (ARPD) inside the tubing, which is associated with the need to clean pipes from deposits, and, consequently, with an increase in the costs associated with the maintenance of pipeline systems.

Known rigid steel tubing lined with plastic pipe RU 91129 U1 dated 26.08.2009, F16L 9/14, F16L 57/00, F16L 58/00) which consist of a metal pipe and an inner plastic pipe, the ends of the plastic pipe are fixed with respect to the metal pipe with thin-walled nozzles with outer flanges. This design protects the pipe from corrosion, due to the significantly lower surface roughness of the plastic pipe, processes of asphalt-wax deposits do not occur. However, these pipes have the disadvantages of rigid steel pipes: high weight; limited length of pipe sections, requires a large number of connections, which leads to a decrease in reliability and an increase in the cost of piping systems.

In recent years, flexible steel pipes of great length are increasingly used.

Known flexible steel pipes used in the oil and gas industry, which are made from a continuous strip of carbon or stainless steel, formed into a pipe and welded at the edges. (US 4863091 dated 09/05/1989, В21С 37/083, В21С 37/08, В23К 31/02 В23К 037/00, В23К 031/00. Flexible steel pipes are produced with various lengths of sections reaching up to 6000 meters and more, wound in This allows the use of this pipe in deviated wells, reduces the cost of pipe transportation, accelerates the process of running the pipe into the well.However, these pipes are prone to corrosion, have a large mass, and the high surface roughness characteristic of all steel pipes initiates the processes of asphalt-wax deposits inside the pumping station. In addition, for the manufacture of these pipes, expensive alloys produced by a limited number of manufacturers are used, which complicates the distribution of these pipes and the replication of production complexes for their production.

Polymer pipes have a high resistance to corrosion and formation of deposits, but in a single-layer version their low pressure resistance does not meet the requirements of end users of the oil and gas industry.

Known flexible polymer pipes made of a continuous layer of polymer material, inside which there are longitudinal reinforcing elements in the form of a metal tape, laid at an angle of 70-85 degrees to the pipe axis, and transverse reinforcing elements in the form of two opposite strands of metal wires having the shape of a spiral and the twist angle to the pipe axis is 15-30 degrees (RU 2315223 C1 dated April 13, 2006, F16L 11/08). Similar pipes are also described in API Recommended Practice 17B, Recommended Practice for Flexible Pipe, 3rd Edition, March 2002, and API Specification 17J, Specification for Unbonded Flexible Pipe, 2nd Edition, November 1999 These pipes are highly resistant to corrosion and deposits. However, due to the reinforcement with metal tapes and wires, such pipes have a large mass. In addition, the lack of adhesion between the steel cord and the polymer matrix of the pipe body also limits the possibility of obtaining pipes with high pressure resistance, leads to pipe delamination, and penetration through the fitting joints of liquid media from the pipe cavity to the steel reinforcement through capillaries at the wire-polymer interface "damages the pipe reinforcement system by the" crevice corrosion "mechanism.

Known flexible pipes made of composite material in which the polymer matrix of the composite is made of cross-linked polyethylene, and the filler is in the form of a volumetric reinforcing system embedded inside the matrix of high-strength continuous threads of aramid fiber, made in the form of a combination of longitudinal and angled to each other and to the axis of the pipe of threads, forming several intertwined spirals (RU 171221 U1 dated 03/13/2017, F16L 9/12). Such pipes are highly resistant to corrosion and deposit formation and are flexible. However, due to the lack of adhesion between the reinforcing threads, such pipes do not have high pressure resistance, in the range of 4.0 ... 10.0 MPa.

The closest solution to the present utility model is the well-known composite thermoplastic pipes (WO 1995/007428 dated 03.16.1995, IPC В32В 1/08, В32В 27/08, F16L 9/128), also described in API Specification 15S, "Spoolable Reinforced Plastic Line Pipe, 2nd Edition, March 2016

They are pipes having an inner tube consisting of a thermoplastic polymer on which a composite layer is applied, which has a cohesive connection with the inner tube, or in some cases, a polymer tape reinforced with unidirectional fibers is wound on the inner tube without forming a bond.

A common problem with these pipes is that the connection between the polymer tape reinforced with unidirectional fibers and the contact surface of the inner polymer pipe, in the case of a close to optimal combination of materials, is insufficient to withstand the loads during installation and operation in the harsh conditions to which pipes of this type are subjected. This, for example, leads to delamination of the composite thermoplastic pipe under conditions of a rapid decrease in gas pressure or under the influence of significant bending forces. Therefore, in these pipes, attempts are being made to use the same type of polymer for the inner pipe, and a composite matrix of polymer tapes reinforced with unidirectional fibers, (see, for example, "Thermoplastic Composite Pipe: An Analysis And Testing Of A Novel Pipe System For Oil &Gas"; presentation by JLCG de Kanter and J. Leijten at the 17th ICCM Conference in Edinburgh, UK, 2009). At the same time, in order to achieve high pressure resistance of the composite pipe, attempts are made to use the same strong polymers with low fracture toughness for the inner pipe and the composite matrix of polymer tapes reinforced with unidirectional fibers, this leads to the formation of cracks in the composite pipe matrix, especially at low temperatures. or under significant bending forces.

The objective of this utility model is to increase the flexibility and fracture toughness of composite thermoplastic pipes.

USEFUL MODEL DISCLOSURE

The problem is solved by the fact that a composite pipe, which consists of an inner pipe made of a thermoplastic polymer, a surrounding composite material, consisting of a thermoplastic polymer composite material and unidirectional continuous reinforcing fibers, and an outer polymer shell, in which the inner pipe, the composite material and the outer shell smoothly fused with each other by heating, characterized in that the composite material of the composite pipe contains at least one elastic layer of thermoplastic polymer material, the elastic modulus of which is 20 ... 3600 MPa less than the elastic modulus of the thermoplastic polymer of the composite material, and the elastic layer is fused with composite material by heating.

The pressure rating of composite (reinforced) thermoplastic pipes has always been the main requirement for technical properties from the point of view of the end user.

However, at the present time, there are other significant requirements that end users also expect from the composite thermoplastic pipes they use.

The flexibility and ability to resist fracture of composite thermoplastic pipes are of great importance to end users and are currently the most sought after technical properties.

Accurately targeted performance tuning will enable thermoplastic composite pipe manufacturers to successfully promote new offerings (solutions) to the end-user market and help them gain a competitive advantage in the thermoplastic composite pipe market.

In order to achieve high pressure ratings of composite thermoplastic pipes, attempts are being made to use the same type of polymer for the inner pipe, and a composite matrix of polymer tapes reinforced with unidirectional fibers, (see, for example, "Thermoplastic Composite Pipe: An Analysis And Testing Of A Novel Pipe System For Oil & Gas "; presentation by JLCG de Kanter and J. Leijten at the 17th ICCM conference in Edinburgh, UK, 2009). At the same time, in order to achieve high resistance to pressure of a composite reinforced thermoplastic pipe, attempts are made to use strong binder polymers with high elastic modulus and low fracture toughness (also called crack resistance) in the polymer matrix of the composite material (layer) of the pipe.

In reinforced polymer matrices, strength is substantially limited by the strength characteristics of the binder polymer and the strength of the bond between the binder polymer and the reinforcing filler. An increase in the strength of the binder, in particular, leads to a low resistance of products with reinforced polymer matrices to the occurrence and propagation of cracks that cause destruction in the interlayer space under the action of normal and tangential loads arising during the operation of products [1]. Even before reaching the critical load (the load at which the macrocrack begins to grow), the damaged zone in a multilayer fiber-reinforced polymer matrix with a high elastic modulus of the binder polymer can cross several layers of the composite material [2].

The formation of cracks and microcracks in the composite matrix of the pipe ultimately leads to the destruction of the pipe under the influence of high pressure and / or under the influence of significant bending forces (especially at low ambient temperatures).

Moreover, to achieve high pressure resistance, it is required to increase the thickness of the composite material (layer) of the pipe, and this further reduces the fracture toughness of the composite thermoplastic pipe [3].

In this utility model, to increase fracture toughness (crack resistance), it is proposed to separate the composite material of a composite thermoplastic pipe by at least one elastic layer (elastic interlayer) of a thermoplastic polymer material, the elastic modulus of which is 20 ... 3600 MPa less than the elastic modulus of the thermoplastic polymer of the composite material ... On the one hand, this increases the fracture toughness of the composite material of the composite thermoplastic pipe by reducing the unit thickness of the composite material of the pipe (layers of the composite material). On the other hand, it will stop the growth of cracks in the composite material at the interface between the cohesively bonded layers of the composite material of the pipe and the interlayer (s) made of a more elastic polymer material, the polymer of which has a lower elastic modulus and higher fracture toughness than the thermoplastic polymer of the composite material.

Also, another mechanism for increasing the fracture toughness of the pipe is the deviation of the initial direction of the cracks formed in the composite material in the elastic interlayer of a more elastic polymer material, which causes energy consumption (and, therefore, increases the fracture toughness of the composite material). fourteen]. For example, the study [5] showed a high efficiency of the mechanism for increasing fracture toughness due to the deflection of cracks in the elastic layers of multilayer composite plates with a polymer matrix based on thermosetting epoxy resins.

Additionally, the interlayer (s) of a more elastic thermoplastic polymer material based on a polymer with a lower elastic modulus than polymer composite materials allows not only to increase the fracture toughness of the composite thermoplastic pipe, but also to increase the flexibility of the composite thermoplastic pipe as a whole, especially when operating the pipe at low temperatures.

The best result of the implementation of the composite thermoplastic pipe according to the present utility model can be obtained in the variants when the composite material of the composite thermoplastic pipe contains (separated) by several elastic interlayers (layers) of thermoplastic polymer material, the modulus of elasticity of which is 20 ... 3600 MPa less than the modulus of elasticity thermoplastic polymer composite material. In this embodiment, the composite thermoplastic pipe consists of an inner polymer pipe made of a thermoplastic polymer and a reinforcing system surrounding it of alternating zones (layers) of a composite material made of a thermoplastic polymer of a composite material and unidirectional continuous reinforcing fibers with elastic interlayers of a thermoplastic polymer material (polymer) with a lower (by 20 ... 3600 MPa) modulus of elasticity than the thermoplastic polymer of the composite material.

The architecture of the composite thermoplastic pipe proposed in this utility model is in many ways similar to the skeleton of the Euplectella aspergillum deep-sea sponge, in which silica layers are separated by thin organic layers. These thin organic layers significantly increase fracture toughness and are an effective mechanism for stopping, deflecting and neutralizing cracks [4].

Moreover, the composite material of the composite pipe can consist of at least one layer of a tape with a thickness of 5 to 1800 μm from a composite material reinforced with unidirectional continuous fibers of a thermoplastic polymer, wound on the inner pipe or the previous layer at angles from 0 ° to 90 ° to the axis of the inner pipe , and at least one layer of tape with a thickness of 5 to 1800 μm made of composite material reinforced with unidirectional continuous fibers of thermoplastic polymer, wound on the inner pipe or the previous layer at angles from 90 ° to 180 ° to the axis of the inner pipe

The use in a composite material of a thermoplastic composite pipe paired and wound in opposite directions symmetrically relative to the axis of the inner pipe of the layers of strips made of composite material reinforced with unidirectional continuous fibers of thermoplastic polymer makes it possible to reduce the likelihood of delamination, violation of the integrity of the composite material due to the action of torsional stresses (loads) in the composite pipe.

Moreover, in a composite thermoplastic composite pipe, at least one elastic interlayer can be located between two layers of tapes of a composite material reinforced with unidirectional continuous fibers of a thermoplastic polymer, and fused with these two layers of a tape of a composite material reinforced with unidirectional continuous fibers by heating.

Moreover, in a composite thermoplastic composite pipe, at least one elastic interlayer can be located between the inner pipe and a layer of a tape made of a composite material reinforced with unidirectional continuous fibers of a thermoplastic polymer, and fused with an inner pipe and a layer of a tape made of a composite material reinforced with unidirectional continuous fibers by means of heating.

In this case, at least one elastic layer of the composite pipe can consist of at least one layer of a tape made of thermoplastic polymer material with a thickness of 5 to 1500 μm, wound at angles from 0 ° to 180 ° to the axis of the inner pipe on at least one layer of tape made of composite material reinforced with unidirectional continuous fibers of thermoplastic polymer.

Moreover, at least one elastic layer of the composite pipe may consist of at least one layer of a tape made of thermoplastic polymer material with a thickness of 5 to 1500 μm, wound on the inner pipe at angles from 0 ° to 180 ° to the axis of the inner pipe.

In one embodiment of a composite pipe, at least one elastic interlayer may consist of at least two layers of tapes made of thermoplastic polymer material, elastic interlayer with a thickness of 5 to 1500 μm, wound symmetrically in opposite directions relative to each other at angles of 0 ° ... 180 ° to the axes of the inner pipe onto at least one layer of a tape made of a thermoplastic polymer composite material reinforced with unidirectional continuous fibers.

In one of the possible variants of the composite pipe, at least one elastic interlayer can consist of at least two layers of tapes made of thermoplastic polymer material of an elastic interlayer with a thickness of 5 to 1500 microns wound around the inner pipe symmetrically in opposite directions relative to each other at angles of 0 ° ... 180 ° to the axis of the inner tube.

Moreover, in a composite thermoplastic pipe layers of tapes made of a composite material reinforced with unidirectional continuous fibers of a thermoplastic polymer and layers of tapes made of thermoplastic polymer material of an elastic interlayer can be wound on the inner pipe or the previous layer at different angles relative to each other in the range from 0 ° to 180 ° to the axis inner pipe.

Moreover, in a thermoplastic composite pipe, continuous unidirectional reinforcing fibers can be selected from a group of fibers: glass fibers, carbon fibers, aramid fibers, boron fibers, ceramic fibers, basalt fibers, silicon carbide fibers, polyamide fibers, polyester fibers, liquid crystal polyester fibers , polyacrylonitrile fibers, polyimide fibers, polyetherimide fibers, polyphenylene sulfide fibers, polyether ketone fibers, polyetheretherketone fibers, polyketone fibers, ultramolecular polyethylene fibers.

In this case, in the thermoplastic composite pipe, the volume fraction of reinforcing unidirectional continuous fibers in the thermoplastic polymer of the composite material is 15 ... 93%.

Moreover, in a thermoplastic composite pipe, the thermoplastic polymer of the inner pipe, the thermoplastic polymer of the composite material and the polymer of the outer polymer shell are cohesively compatible, and are selected from the group of polymers: polyethylene (PE, HDPE, LDPE), polyethylene of high (increased) heat resistance PE-RT (Polyethylene of Raised Temperature resistance), polyethylene-octene copolymer, polyethylene-octene-1 copolymer, polyethylene-hexene copolymer, polyethylene-hexene-1 copolymer, metallocene high-density polyethylene, polypropylene (PP, PP-R), polypropylene copolymers, polybutene (PB, PB -1), polybutene copolymers, polyvinyl chloride (PVC, HPVC), acrylonitrile butadiene styrene (ABS), polyamide (PA), polyphthalamide (PPA), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polybutylene naphthalate (PBT) (PFA) , fluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), polyethersulfone (PES), polyphenylsulfone (PPSU), polyimide (PI), polyether imide (PEI), polyoxymethylene (POM), polyarylene ether ketone (PAEK), polyetherether ketone (PEEK, REK), polyketone (RK, Polyketon), as well as mixtures and compositions of the above polymers.

Moreover, in a thermoplastic composite pipe, the thermoplastic polymer material of the elastic interlayer is cohesively compatible with the thermoplastic polymer of the composite material and the thermoplastic polymer of the inner pipe, and is selected from the group of polymers: polyethylene (PE, HDPE, LDPE, LLDPE), polyethylene of high (increased) thermal stability PE-RT ( Polyethylene of Raised Temperature resistance), copolymer of polyethylene with octene, copolymer of polyethylene with octene-1, copolymer of polyethylene with hexene, copolymer of polyethylene with hexene-1, metallocene high density polyethylene, polypropylene (PP, PP-R), polypropylene copolymers, polybutene ( PB, PB-1), polybutene copolymers, polyvinyl chloride (PVC, HPVC), acrylonitrile butadiene styrene (ABS), polyamide (PA), polyphthalamide (PPA), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polybutylene naphthalate (Rhypothenol), phthalate (PFA), fluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), polyethersulfone (PES), polyphenylsulfone (PPSU), polyim id (PI), polyether imide (PEI), polyoxymethylene (POM), polyarylene ether ketone (PAEK), polyether ether ketone (PEEK, PEC), polyketone (PK, Polyketon), as well as mixtures and compositions of the above polymers.

In one of the preferred embodiments of the thermoplastic composite pipe, the thermoplastic polymer material of at least one layer of the tape of the elastic interlayer is selected from the group of polymers: polyethylene of increased temperature resistance (PE-RT), copolymer of polyethylene with octene, copolymer of polyethylene with octene-1 , copolymer of polyethylene with hexene, copolymer of polyethylene with hexene-1, metallocene high density polyethylene, polyvinylidene fluoride.

Moreover, in a composite thermoplastic pipe, a thermoplastic polymer material of an elastic interlayer may contain reinforcing unidirectional continuous fibers in a volume fraction of 3 ... 40%.

Moreover, in a composite thermoplastic pipe, a thermoplastic polymer material of an elastic interlayer may contain reinforcing unidirectional continuous fibers in a mass fraction of 3 ... 50%.

At the same time, in a composite thermoplastic pipe, unidirectional continuous reinforcing fibers of the elastic interlayer are selected from the group of fibers: glass fibers, carbon fibers, aramid fibers, boron fibers, ceramic fibers, basalt fibers, silicon carbide fibers, polyamide fibers, polyester fibers, liquid crystal fibers polyester fibers, polyacrylonitrile fibers, polyimide fibers, polyetherimide fibers, polyphenylene sulfide fibers, polyether ketone fibers, polyether ether ketone fibers, polyketone fibers, ultramolecular polyethylene fibers.

In one of the preferred embodiments of the thermoplastic composite pipe, a thermoplastic polymer with an elastic modulus of 800 ... 1600 MPa (for example, high density polyethylene HDPE) is selected as the thermoplastic polymer of the inner pipe, the polymer shell and the thermoplastic polymer of the composite material, and the thermoplastic polymer material of the elastic interlayer is selected thermoplastic polymer with an elastic modulus of 350 ... 780 MPa (for example, polyethylene of increased temperature resistance (PE-RT) of the common brands Dowlex 2344, Dowlex 2388, Dowlex 2377, Dowlex 2355 - manufactured by Dow Chemical; DX800 - manufactured by SK Corporation; XP9000, XP9020 - manufactured by Daelim ; SP980, SP988 - manufacturer LG Chem; PE6PP-34 - manufacturer LUKOIL; ELTEX TUB220-RT - manufacturer INEOS, XRT-70 - manufacturer TOTAL).

To obtain a composite thermoplastic pipe with improved temperature resistance and flexibility, in one of the preferred versions of the thermoplastic composite pipe, a thermoplastic polymer with an elastic modulus of 500 ... 850 MPa is selected as a thermoplastic polymer of an inner pipe, a polymer shell and a thermoplastic polymer of a composite material (for example, for example, polyethylene of increased thermal resistance (PE-RT) of common brands Dowlex 2344, Dowlex 2388, Dowlex 2377 - manufactured by Dow Chemical; DX800 - manufactured by SK Corporation; XP9000, XP9020 - manufactured by Daelim; SP980, SP988 - manufactured by LG Chem; PE6PP-34 - manufactured by LUKOIL; ELTEX TUB220-RT - manufacturer INEOS, XRT-70 - manufacturer TOTAL); and as a thermoplastic polymer material of the elastic interlayer a thermoplastic polymer with an elastic modulus of 250 ... 480 MPa (for example, polyethylene of increased temperature resistance (PE-RT) of Dowlex 2355 brand - manufactured by Dow Chemical) is chosen.

To obtain a composite thermoplastic pipe in one of the variants of a thermoplastic composite pipe, a thermoplastic polymer with a modulus of elasticity of 6500 ... 9700 MPa (for example, polyetheretherketone (PEEK) grades ustaPEEK GF (9700 MPa) , SustaPEEK CF (6500 MPa) - manufacturer Roechling); and as the thermoplastic polymer material of the elastic interlayer a thermoplastic polymer with an elastic modulus of 4000 MPa (for example, polyetheretherketone (PEEK) of SustaPEEK brands - manufacturer of Roechling), Victrex PEEK - manufacturer of Victrex, Gehr PEEK - manufacturer is selected. Gehr, TecaPEEK - Ensinger, Ketron PEEK - Quadrant).

Also, to obtain a composite thermoplastic pipe in one of the variants of a thermoplastic composite pipe, a thermoplastic polymer with an elastic modulus of 4000 MPa (for example, polyetheretherketone (PEEK) brands SustaPEEK - manufacturer Roechling) is selected as a thermoplastic polymer of an inner pipe, a polymer shell and a thermoplastic polymer of a composite material, Victrex PEEK - manufacturer Victrex, Gehr PEEK - manufacturer. Gehr, TecaPEEK - manufacturer Ensinger, Ketron PEEK - manufacturer Quadrant); and a thermoplastic polymer with an elastic modulus of 900 ... 1350 MPa (for example, polyketone (PK) grades Poketone M630F (1350 MPa), Poketone M730F (1200 MPa), Poketone M710F (900 MPa) - manufactured by Hyosung) ...

Moreover, the inner tube of the thermoplastic polymer of the thermoplastic composite tube can be manufactured by extrusion methods.

Moreover, a composite material consisting of a thermoplastic polymer of a composite material and continuous unidirectional reinforcing fibers can be manufactured by winding with tension on an inner pipe and / or on an elastic interlayer (s) of layers of tapes of a composite material reinforced with continuous unidirectional fibers of a thermoplastic polymer, which smoothly fused with each other, with the outer surface of the pipe, and an elastic interlayer by heating the surfaces of the pipe and tapes to the Vicat softening temperature or to the melting temperature until a homogeneous connection is formed between the outer surface of the inner pipe, with the adjacent layer of tapes (layers) of composite material reinforced with continuous unidirectional fibers of the thermoplastic polymer of the composite material between themselves, and the layer (s) of the elastic (x) interlayer (s).

Moreover, an elastic layer of a polymer material can be made by winding with tension on the layer (s) of the composite material and / or on the outer surface of the inner pipe of the layers of strips made of polymer material of the elastic layer, which are smoothly fused with each other and with the surfaces of the composite material and / or the inner pipes by heating the surfaces of the belts of the elastic interlayer, the composite material of the pipe and the inner pipe to the Vicat softening temperature or to the melting temperature until a homogeneous connection is formed between the surfaces of the layer (s) of the elastic interlayer (s) and the layers of the composite material, and or the surface of the inner pipe ...

Moreover, the outer polymer shell of the composite thermoplastic pipe can be manufactured by extrusion methods by extrusion onto the outer surface of the composite material preheated to the Vicat softening temperature or melting.

Moreover, the outer polymer shell of the thermoplastic composite pipe can also be made by heat shrinkage on the outer surface of the composite material of the finished polymer shell (protective pipe) preheated to the Vicat softening temperature or melting.

Moreover, for the manufacture of a thermoplastic composite pipe according to the present utility model, ready-made, industrially manufactured tapes of composite material and tapes of an elastic layer using reinforcing fibers and polymers listed in this utility model can be used. Currently, tapes (prepegs) made of polymeric materials, and thermoplastic polymers and unidirectional continuous reinforcing fibers (UD tapes) are widely available on the market. For example, UD tapes from Togau Advanced Composites (USA), BUFA Thermoplastic Composites GmbH & Co. KG (Germany), TOPOLO (China).

Moreover, for the manufacture of a thermoplastic composite pipe according to the present utility model, the tape of the composite material and the tape of the elastic interlayer using the reinforcing fibers and polymers listed in this utility model can be manufactured industrially using the existing industrial equipment. For example, industrial equipment for the production of strips (prepegs) from continuous unidirectional reinforcing fibers and thermoplastic polymers is offered by the following companies: KraussMaffei (Germany), GPM Machinery (China).

At the same time, for the manufacture of tapes (prepegs) from continuous unidirectional reinforcing fibers and thermoplastic polymers, thermoplastic polymers listed in this utility model and fibers also listed in this utility model with a fiber cross-section selected from the group: round, rectangular, oval, elliptical or cocoon-shaped.

Moreover, for winding and fusing layers of tapes reinforced with continuous fibers of composite material and tapes of an elastic layer of a pipe made of polymer materials of a composite thermoplastic pipe, existing industrial equipment can be used. For example, industrial equipment for winding layers of belts reinforced with continuous fibers is offered by the following companies: KraussMaffei (Germany), Fartrouven R&D (Portugal), GPM Machinery (China).

TECHNICAL RESULT

The technical result of this utility model:

- increase in fracture toughness (crack resistance) of composite thermoplastic pipes;

- increasing the flexibility of composite thermoplastic pipes.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a photo of the deviation of a microcrack in the soft interlayer of the skeleton of a deep-sea sponge.

FIG. 2 shows a schematic diagram of a composite thermoplastic pipe consisting of an inner pipe, a surrounding composite material, separated by elastic interlayers.

EXAMPLE OF IMPLEMENTING A UTILITY MODEL

As shown in FIG. 2, the composite pipe consists of an inner pipe made of a thermoplastic polymer 1, a surrounding composite material 2, separated by elastic interlayers 3, and a polymer shell 4, which are fused along the adjacent surfaces.

A composite thermoplastic pipe is manufactured in three stages, which are realized sequentially either in one production line or in three separate production lines (production sites).

The first stage includes the production of an inner tube from a thermoplastic polymer by extrusion.

The second stage includes winding with tension on the inner tube of tapes made of composite material reinforced with unidirectional continuous fibers of thermoplastic polymer, and tapes of thermoplastic material of elastic interlayer. In this case, the outer surface of the inner pipe is fused with the bordering surface of the reinforced tapes of the composite material. In this case, the reinforced tapes of the composite material and the tapes of the elastic layer are fused together by heating. If the composite material and the elastic layer consist of several layers of tapes, then they are also fused layer by layer with each other by heating. The fusion of the layers of a thermoplastic composite pipe is carried out when heated to the Vicat softening temperature or the melting temperature of the polymers that make up the reinforced tapes and the polymer of the inner pipe.

The third stage includes the application to the adjoining outer surface of the composite material heated to the Vicat softening temperature or the melting temperature of the thermoplastic polymer of the composite material, the outer polymer shell by extrusion, or by heat shrinking of the finished polymer shell (pipe).

The device works as follows:

The growth of cracks in the composite material of the thermoplastic composite pipe arising under the influence of the internal pressure of the transported media or under the influence of bending loads stops at the interface with the polymer material of the elastic interlayer, or cracks occurring in the composite material deviate from the initial direction in the elastic interlayer consuming energy. Thereby, the fracture toughness (crack resistance) of the fracture toughness of the thermoplastic composite pipe is increased.

Additionally, due to the fact that the elastic interlayers consist of a thermoplastic polymer material, the modulus of elasticity of which is 20 ... 3600 MPa less than the modulus of elasticity of the thermoplastic polymer of the composite material, the flexibility of the composite pipe increases.

The proposed device is rinsely applicable using existing technical means. (It is planned to start serial production in Q1 2020)

A person skilled in the art will appreciate that various modifications and variations are possible in the present invention. Accordingly, it is assumed that this utility model covers possible modifications and changes, as well as their equivalents, without departing from the essence and scope of the utility model disclosed in the attached utility model claims.

Literature

1.V.A. Bolshakov, V.I. Solodilov, R.A. Korokhin, S.V. Kondratov, Yu.I. Merkulova, T.P. Dyachkova. Investigation of crack resistance of polymer composite materials manufactured by infusion using various concentrates based on modified CNTs. UDC 678.8: 620.1, Proceedings of VIAM No. 7 (55) 2017, p. 79-89. http://viam-works.ru/ru/articles?art_id=1131

2. V.E. Yudin, A.M. Leksovsky. Viscoelasticity of the Polymer Matrix and Fracture of Heat Resistant Fiber Composites. Solid State Physics, 2005, volume 47, no. 5, p. 944.https: //joumals.ioffe.ru/articles/3838

3. Broek D. Fundamentals of fracture mechanics / Per. from English M .: Higher school, 1980 .-- 368 p.

4. A. Woesz, J.C. Weaver, M. Kazanci, Y. Dauphin, J. Aizenberg, D.E. Morse, P. Fratzl, Micromechanical properties of biological silica in skeletons of deep-sea sponges, J. Mater. Res. 21 (2006) 2068-2078.

5. Yokozeki T., Iwahori Y., Ishibashi M. et al. Fracture toughness improvement of CFRP laminates by dispersion of cup-stacked carbon nanotubes // Composites Science and Technology. 2009. Vol. 69. P. 2268-2273.

Claims (15)

1. A composite pipe, which consists of an inner pipe made of thermoplastic polymer, a surrounding composite material consisting of a thermoplastic polymer composite material and unidirectional continuous reinforcing fibers, and an outer polymer shell, in which the inner pipe, the composite material and the outer polymer shell are smoothly fused to each other. with another by heating, characterized in that the composite material contains elastic interlayers of thermoplastic polymer material, the elastic modulus of which is 20 ... 3600 MPa less than the elastic modulus of the thermoplastic polymer of the composite material, and the elastic interlayer is fused with the composite material by heating. 2. A composite pipe according to claim 1, in which the composite material includes at least one layer of tape with a thickness of 5 μm to 1800 μm of a composite material reinforced with unidirectional continuous fibers of a thermoplastic polymer, wound on the inner pipe or the previous layer at angles from 0 ° up to 90 ° to the axis of the inner pipe, and at least one layer of tape with a thickness of 5 μm to 1800 μm of composite material reinforced with unidirectional continuous fibers of thermoplastic polymer, wound on the inner pipe or the previous layer at angles from 90 ° to 180 ° to the axis inner pipe. 3. Composite pipe according to PP. 1 and 2, in which at least one elastic interlayer is located between two layers of unidirectional continuous fibers reinforced thermoplastic polymer composite material and fused with these two layers of tape of unidirectional continuous fibers reinforced thermoplastic polymer composite material by heating. 4. Composite pipe according to PP. 1 and 2, in which at least one elastic interlayer is located between the inner tube and a layer of tape of unidirectional continuous fibers reinforced thermoplastic polymer composite material and fused with the inner pipe and a layer of tape of unidirectional continuous fibers reinforced thermoplastic polymer composite material by heating. 5. Composite pipe according to claim 3, in which at least one elastic interlayer consists of at least one layer of a tape of thermoplastic polymer material with a thickness of 5 μm to 1500 μm, wound at angles from 0 ° to 180 ° to the axis of the inner pipe on at least one layer of tape made of thermoplastic polymer composite material reinforced with unidirectional continuous fibers. 6. Composite pipe according to claim 4, in which at least one elastic interlayer consists of at least one layer of a tape of thermoplastic polymer material with a thickness of 5 μm to 1500 μm, wound on the inner pipe at angles from 0 ° to 180 ° to the axis of the inner pipe. 7. A composite pipe according to claim 3, in which at least one elastic interlayer consists of at least two layers of tapes made of thermoplastic polymer material, an elastic interlayer with a thickness of 5 μm to 1500 μm, wound symmetrically in opposite directions relative to each other at angles of 0 … 180 ° to the axis of the inner pipe by at least one layer of tape made of composite material reinforced with unidirectional continuous fibers of thermoplastic polymer. 8. A composite pipe according to claim 4, in which at least one elastic interlayer consists of at least two layers of thermoplastic polymeric material tapes of an elastic interlayer with a thickness of 5 μm to 1500 μm, wound around the inner pipe symmetrically in opposite directions relative to each other at angles of 0 ... 180 ° to the axis of the inner pipe. 9. A composite pipe according to claim 1, in which the layers of tapes made of a thermoplastic polymer composite material reinforced with unidirectional continuous fibers and layers of tapes of a thermoplastic polymer material of an elastic interlayer are wound on the inner pipe or the previous layer at different angles relative to each other and in the range from 0 ° up to 180 ° to the axis of the inner tube. 10. The composite pipe of claim 1, wherein the unidirectional continuous reinforcing fibers of the composite material are selected from the group of fibers: glass fibers, carbon fibers, aramid fibers, boron fibers, ceramic fibers, basalt fibers, silicon carbide fibers, polyamide fibers, polyester fibers , liquid crystal polyester fibers, polyacrylonitrile fibers, polyamide fibers, polyetherimide fibers, polyphenylene sulfide fibers, polyether ketone fibers, polyetheretherketone fibers, polyketone fibers, ultramolecular polyethylene fibers. 11. Composite pipe according to PP. 1 and 10, in which the volume fraction of reinforcing unidirectional continuous fibers in the thermoplastic polymer of the composite material is 15 ... 93%. 12. The composite pipe according to claim 1, in which the thermoplastic polymer of the inner pipe, the thermoplastic polymer of the composite material and the polymer of the outer polymer shell are cohesively compatible and are selected from the group of polymers: polyethylene, polyethylene of increased heat resistance, copolymer of polyethylene with octene, copolymer of polyethylene with octene-1 , copolymer of polyethylene with hexene, copolymer of polyethylene with hexene-1, metallocene high density polyethylene, polypropylene, copolymers of polypropylene, polybutene, copolymers of polybutene, polyvinyl chloride, acrylonitrile butadiene styrene, polyamide, polyphthalylene, polyethylene terephthaluoroethylene polyvinylidene fluoride, polyphenylene sulfide, polyethersulfone, polyphenylsulfone, polyimide, polyetherimide, polyoxymethylene, polyarylene ether ketone, polyether ether ketone, polyketone, as well as mixtures and compositions of the above polymers. 13. The composite pipe according to claim 1, in which the thermoplastic polymer material of the elastic interlayer is cohesively compatible with the thermoplastic polymer of the composite material and the thermoplastic polymer of the inner pipe and is selected from the group of polymers: polyethylene, polyethylene of increased heat resistance, copolymer of polyethylene with octene, copolymer of polyethylene with octene - 1, polyethylene-hexene copolymer, polyethylene-hexene-1 copolymer, metallocene high-density polyethylene, polypropylene, polypropylene copolymers, polybutene, polybutene copolymers, polyvinyl chloride, acrylonitrile butadiene styrene, polyamide, polyphthalamide, polyethylene terephthalamide, polyethylene terephthalamide, polyethylene terephthylene , polyvinylidene fluoride, polyphenylene sulfide, polyethersulfone, polyphenylsulfone, polyimide, polyetherimide, polyoxymethylene, polyarylene ether ketone, polyether ether ketone, polyketone, as well as mixtures and compositions of the above polymers. 14. A composite pipe according to claim 1, in which the thermoplastic polymer material of the elastic interlayer contains reinforcing unidirectional continuous fibers in a volume fraction of 3 ... 45%. 15. The composite pipe of claim 14, wherein the unidirectional continuous reinforcing fibers are selected from the group of fibers: glass fibers, carbon fibers, aramid fibers, boron fibers, ceramic fibers, basalt fibers, silicon carbide fibers, polyamide fibers, polyester fibers, fibers liquid crystal polyester fibers, polyacrylonitrile fibers, polyimide fibers, polyetherimide fibers, polyphenylene sulfide fibers, polyether ketone fibers, polyetheretherketone fibers, polyketone fibers, ultramolecular polyethylene fibers.

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