A fibre-reinforced thermoplastic unidirectional barrier tape, a method of manufacturing and use thereof and a reinforced thermoplastic pipe and method of manufacturing thereof

Abstract

A fibre-reinforced thermoplastic unidirectional (UD) barrier tape arranged for use in a reinforced transportation pipe (RTP) configured for transporting fluids, wherein the UD barrier tape comprises a barrier coating comprising platelets, wherein said barrier coating is present on at least a part of the first side of the UD barrier tape for forming a barrier between the two or more layers of the UD tape and the thermoplastic inner liner of the RTP and / or wherein said barrier coating is present on at least a part of the second side of the UD barrier tape for forming a barrier between the two or more layers of the UD tape and the thermoplastic outer jacket of the RTP.

Description

[0001] TITLE A fibre-reinforced thermoplastic unidirectional barrier tape, a method of manufacturing and use thereof and a reinforced thermoplastic pipe and method of manufacturing thereof

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a fibre-reinforced thermoplastic unidirectional (UD) barrier tape, to a method of manufacturing the fibre-reinforced thermoplastic UD barrier tape and to a use of the fibre-reinforced thermoplastic UD barrier tape. The present disclosure further relates to a reinforced thermoplastic pipe (RTP) comprising the fibre-reinforced thermoplastic UD barrier tape and to a method of manufacturing the RTP comprising the fibre-reinforced thermoplastic UD barrier tape.

[0004] BACKGROUND

[0005] Introduced more than a half century ago, fibre-reinforced polymer compositions are composite materials with a wide range of applications in industry, for example in the automotive industry. The term "composite" can apply to any combination of individual materials, for example to a thermoplastic polymer (the matrix) in which fibres (reinforcing filler) have been dispersed. The reinforced plastics industry has used glass fibres in different forms for reinforcing polymer matrices to produce a diversity of products.

[0006] An example of the variety of products are fibre-reinforced thermoplastic unidirectional (UD) tapes. Fibre-reinforced thermoplastic UD tapes are endless tapes that are reinforced with continuous fibres, wherein the fibres, e.g., glass, basalt, or carbon fibres, are unidirectionally aligned and embedded (dispersed) in a thermoplastic matrix material of the tape. UD tapes are often used in spoolable reinforced thermoplastic pipes (RTPs), that are for example used for transporting fluids, like hydrocarbon fluids. The RTPs are sought in oil and gas transport to replace carbon steel pipes, which have the tendency to corrode. An RTP usually comprises an inner liner, through which the hydrocarbon fluid flows, an outer jacket, and, positioned between the inner liner and the outer jacket, a reinforcement layer. The reinforcement layer comprises the UD tape.

[0007] The UD tape comprises fibres, such as glass fibres, that are used as reinforcement of the RTP. However, the fibres are susceptible to attack by water and acidic gases, like H2S, and CO2, which are present in the hydrocarbon fluids (oil). These destroy the strength of the fibres.

[0008] The oil contains aliphatic and aromatic hydrocarbons, but also CH4, H2S, CO2and H2O. The glass fibres in the UD tapes are susceptible to attack and damage by these gases diffusing outwards through the thermoplastic inner liner. The hydrocarbons do not attack the fibres and in any case, apart from CH4, none of them migrate through the inner liner tube. The gases have to permeate through the inner liner, and through the thermoplastic matrix of the UD tape to come into contact with the reinforcing fibres.

[0009] RU204545U1 discloses a barrier layer which does not secure aligned fillers. The reference teaches fusing / lamination with heating, which creates a high risk of loosening the alignment / stacking of fillers.

[0010] EP4279654A1 discloses an oxygen barrier for laminated packaging films, and as such fails to address the operational requirements of RTP pipes where a barrier for fluid oil and gas mixture is needed.

[0011] W02014 / 063009A1 references material and process for coating on substrates in general. The reference is silent as to the dispensation / melting of a gas barrier clay coating layerwithout disorientation. Such disorientation can permit undesirable oil / gas permeation.

[0012] As such there exists a need to protect the fibres from attack by the hazardous gases that diffuse through the thermoplastic inner liner. OBJECTIVE

[0013] It is therefore an object of the present invention to provide for an improved fibre- reinforced thermoplastic unidirectional (UD) barrier tape arranged for use in a reinforced transportation pipe (RTP) configured for transporting fluids.

[0014] SUMMARY

[0015] The foregoing object is achieved according to a first aspect of the invention that relates to a fibre-reinforced thermoplastic unidirectional (UD) barrier tape arranged for use in a reinforced transportation pipe (RTP) configured for transporting fluids, said RTP comprising from a centre to a periphery a thermoplastic inner liner; a reinforcing layer, comprising two or more layers a fibre-reinforced thermoplastic unidirectional (UD) tape and wherein at least one of said two or more layers of the UD tape is said UD barrier tape; and a thermoplastic outer jacket, wherein said UD barrier tape has a first side facing towards the centre of the RTP and a second side facing towards the periphery of the RTP, wherein said UD barrier tape comprises a thermoplastic matrix material and unidirectionally aligned reinforcing fibres dispersed within said thermoplastic matrix material, wherein said unidirectionally aligned reinforcing fibres extend in a longitudinal direction of the UD barrier tape, and wherein the UD barrier tape further comprises a barrier coating comprising platelets, wherein said barrier coating is present on at least a part of the first side of the UD barrier tape for forming a barrier between the two or more layers of the UD tape and the thermoplastic inner liner of the RTP and / or wherein said barrier coating is present on at least a part of the second side of the UD barrier tape for forming a barrier between the two or more layers of the UD tape and the thermoplastic outer jacket of the RTP.

[0016] Regarding RU204545U1 , the reference discloses barrier layers fused / laminated by heating. As such there is an inner liner, wrapped with two types of composite tapes which are fusion bonded to the inner liner, and there is a jacket with the same matrix polymer on top. The two types of composite tapes are (1) fibre composite tape and (2) a tape with inorganic platelets in a polymer matrix. That is, two types of tape have to be extruded and made on rolls, and then wrapped on the inner liner tube and fusion bonded. This references teaches a barrier layer that does not secure aligned fillers to produce desired barrier properties. As such, the references barrier less effective than desired.

[0017] In contrast, the present subject matter can apply a thin layer of barrier layer on an extruded surface (e.g. tape) with a specific described process like printing. This can secure platelet-like particles in the barrier in a desired alignment. For example, they can be stacked onto each other to cover the surface, e.g. the full surface. This can provide improved barrier properties.

[0018] The present subject matter reduces the chances for loosening alignment by applying the coating on more rigid tape with fibers backing / supporting. The tape of the present teaching can also be applied without consolidation / fusing.

[0019] The fibres are oriented in the longitudinal direction of the UD barrier tape to provide a continuous tape, which can be made kilometres long, which is preferred for a winding process for continuity. The fibres will be also oriented in the loading direction as the UD barrier tape is wound under an optimum angle, e.g., approx. 55.4 degrees. Fibres oriented in the loading direction results in maximum utilization of the performance of the fibres.

[0020] The effect of the platelets in the barrier coating is that the platelets will have a planar arrangement and are oriented parallel and staggered relative to each other in the barrier coating. The barrier coating comprising platelets improves protection of the reinforcing layer of the UD barrier tape, in particular the reinforcing fibres embedded in the thermoplastic matrix material, against gases / small molecules, such as CO2, O2, H2O, H2S, and CH4. The barrier coating protects the reinforcing fibres against these hazardous gases, such that the UD barrier tape’s strength is maintained throughout its service life. Hence, the UD barrier tape enhances the lifetime of service of the RTP, thereby reducing maintenance work and thus, reducing costs. In a second aspect, the invention relates to a method of manufacturing a fibre- reinforced thermoplastic unidirectional (UD) barrier tape according to the first aspect of the present invention, said method comprising: inkjet printing in a roll-to-roll process, flexo printing, rotogravure printing, or Meyer bar coating, an aqueous or non-aqueous ink, said ink comprising platelets and a monomer that can be subsequently polymerized by heating said monomer below a melting point of the thermoplastic matrix material, on a first side and / or a second side of a UD tape to provide the UD barrier tape on which the barrier coating is present on at least a part of the first side and / or the second side of the UD tape; or spray coating an aqueous or non-aqueous ink, said ink comprising platelets and a monomer that can be subsequently polymerized by heating said monomer below a melting point of the thermoplastic matrix material, on a first side and / or a second side of a UD tape to provide the UD barrier tape on which the barrier coating is present on at least a part of the first side and / or the second side of the UD tape.

[0021] In a third aspect, the invention relates to a use of a fibre-reinforced thermoplastic unidirectional (UD) barrier tape according to the first aspect of the present invention or manufactured according to the method according to the second aspect of the present invention for a reinforced thermoplastic pipe (RTP) configured for transporting of fluids, said RTP comprising from a centre to a periphery a thermoplastic inner liner; a reinforcing layer, comprising two or more layers of a fibre-reinforced thermoplastic unidirectionally (UD) tape and wherein at least one or said two or more layers of UD tape is said UD barrier tape; and a thermoplastic outer jacket.

[0022] In a fourth aspect, the invention relates to a reinforced thermoplastic pipe (RTP) configured for transporting fluids, said RTP comprising from a centre to a periphery: a thermoplastic inner liner; a reinforcing layer, comprising two or more layers of a fibre-reinforced thermoplastic unidirectionally (UD) tape and wherein at least one or said two or more layers of UD tape is a UD barrier tape according to the first aspect of the present invention or manufactured according to the second aspect of the present invention; and a thermoplastic outer jacket.

[0023] In a fifth aspect, the invention relates to a method of manufacturing a reinforced thermoplastic pipe (RTP) according to the fourth aspect of the present invention, comprising the steps of:

[0024] 1) providing the thermoplastic inner liner;

[0025] 2) one or more steps of winding on the thermoplastic inner liner the two or more layers of the UD tape, wherein during each winding step, one or more layers of UD tape is / are applied, thereby forming the reinforcing layer on the thermoplastic inner liner;

[0026] 2a) optionally, heating (209i) the reinforcing layer at a temperature about 10 °C above the melting temperature of the thermoplastic matrix material and cooling (209ii) to bond the reinforcing layer and the thermoplastic inner liner; and

[0027] 3) applying the thermoplastic outer jacket on the reinforcing layer to provide the RTP having the barrier coating.

[0028] Corresponding embodiments disclosed below for the first aspect are also applicable for the method of manufacturing the UD barrier tape (second aspect), the use of the UD barrier tape (third aspect), to the RTP comprising the UD barrier tape (fourth aspect), and to the method of manufacturing the RTP comprising the UD barrier tape (fifth aspect) according to the present invention, unless stated otherwise.

[0029] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention is elucidated below with a detailed description.

[0031] Thermoplastic matrix material

[0032] In the present description, with “thermoplastic matrix material” is meant a thermoplastic polymer material that forms the matrix of the fibre-reinforced thermoplastic composite. The thermoplastic polymer material may comprise of at least one non-polar polymer and / or at least one polar-polymer. Non-polar polymers

[0033] In the present description, with “non-polar polymer” is meant a type of polymer that lacks significant polar functional groups or has a symmetrical molecular structure that results in an even distribution of charge. In non-polar polymers, the electronegativity of the atoms involved is relatively balanced, leading to a lack of a net dipole moment within the polymer molecule.

[0034] Non-polar polymers typically exhibit properties such as low surface energy, resistance to polar solvents, and lower reactivity with other polar substances. They are often used in applications where these characteristics are advantageous, such as in packaging materials, insulating coatings, and non-stick surfaces.

[0035] The thermoplastic matrix material comprises at least one non-polar polymer, such as polyolefins, polytetrafluoroethylene, or polyphenylene sulphide.

[0036] In the present description, with “polyolefin” is meant a polymer of olefin monomers, having the general formula (CH2CHR)nwhere R is an alkyl group. Examples are polyethylene, polypropylene, and polymethylpentene.

[0037] In the present description, with “PE” is meant polyethylene which is according to the structure below:

[0038] PE is usually a mixture of similar polymers of ethylene, with various values of n. It is a thermoplastic, non-polar polymer and can be low-density or high-density and many variations thereof. PE is relatively cheap and therefore commonly employed in packaging materials, containers and various plastic products.

[0039] In the present description, with “PP” is meant polypropylene which is according to the structure below:

[0040] PP is a thermoplastic, non-polar polymer and is very similar to PE, but a much stronger polymer. Like PE, it is a relatively cheap polymer making it a popular choice in manufacturing.

[0041] In the present description, with “PMP” is meant polymethylpentene which is according to the structure below:

[0042] PMP is a thermoplastic, non-polar polymer that has high heat resistance and low density. It has similar properties of PE and PP, although it is more brittle and more gas permeable.

[0043] In the present description, with “PTFE” is meant polytetrafluoroethylene according to the structure below:

[0044] Polytetrafluoroethylene is a fluorocarbon solid, as it is a high-molecular-weight polymer consisting wholly of carbon and fluorine.

[0045] In the present description, with “PPS” is meant polyphenylene sulphide according to the structure below:

[0046] This is a thermoplastic polymer consisting of aromatic rings linked by sulphides.

[0047] In the present description, with “PPO” is meant polyphenylene oxide according to the structure below:

[0048] Polyphenylene oxide (PPO), also known as polyphenylene ether, also has the polar ether linkage. This polymer has high hydrolytic and chemical stability and creep resistance at high temperatures. Neat PPO is thermally unstable at melting and extrusion temperatures. It is modified with polystyrene (PS), a non-polar polymer. The modified PPO is used for extrusion purposes. The modified PPO, which is a blend of PPO and PS, is a miscible system.

[0049] In an embodiment, the at least one non-polar polymer is selected from the group consisting of a polyolefin - such as polyethylene (PE), polypropylene (PP) and polymethylpentene (PMP) - polytetrafluoroethylene (PTFE), polyphenylene sulphide (PPS), polyphenylene oxide (PPO), and a combination of two or more thereof, preferably a polyolefin, such as polyethylene (PE) and polypropylene (PP).

[0050] Polar polymers

[0051] In the present description, with “polar polymer” is meant a type of polymer that contains polar functional groups or asymmetric structures, leading to an uneven distribution of charge within the polymer molecule. Polar functional groups typically involve electronegative atoms, such as oxygen, nitrogen, or fluorine, which create regions of partial negative and positive charges within the molecule.

[0052] In a polar polymer, the distribution of electrons is not uniform, resulting in a net dipole moment. This dipole moment gives the polymer certain properties, including enhanced interactions with other polar substances, higher surface energy, and specific electrical characteristics. Polar polymers often exhibit different physical and chemical properties compared to non-polar polymers. They may have higher melting points, be more prone to interaction with polar solvents, and display different surface behaviours.

[0053] The thermoplastic matrix material comprises at least one polar polymer, such as polyester, polyamide, aliphatic polyketone, aromatic polyketone, polyurethane, polyether sulfone, polyetherimide, polyvinyl chloride, polyvinylidene fluoride, polyvinyl acetate, polyacrylonitrile, polycarbonate.

[0054] In the present description, with “polyester” is meant a polymer that contains an ester functional group in every repeat unit of their main chain and is according to the structure below:

[0055] Examples of polyesters are polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and liquid-crystal polyester.

[0056] In the present description, with “PET” is meant polyethylene terephthalate according to the structure below:

[0057] PET is a thermoplastic, polar polymer that consists of repeating (CI0H8O4) units. It was formerly produced from ethylene glycol (monoethylene glycol, MEG) and dimethyl terephthalate (DMT) but mostly produced now by the reaction of MEG with terephthalic acid (purified terephthalic acid, PTA).

[0058] In the present description, with “PBT” is meant polybutylene terephthalate according to the structure below: PBT is a thermoplastic, polar polymer that is closely related to PET. Compared to PET, PBT has slightly lower strength and rigidity, slightly better impact resistance, and a slightly lower glass transition temperature.

[0059] In the present description, with “PEN” is meant polyethylene naphthalate according to the structure below:

[0060] PEN is a thermoplastic, polar polymer derived from naphthalene-2,6-dicarboxylic acid and ethylene glycol (MEG). It is related to PET, but with superior barrier properties.

[0061] In the present description, with “LCP” is meant liquid-crystal polyester which is a polymer having the property of forming a liquid crystal melt, usually containing aromatic rings as mesogens.

[0062] In the description, with “mesogen” is meant a compound that displays liquid crystal properties and can best be described as disordered solids or ordered liquids because they arise from a unique state of matter that exhibits both solid- and liquid-like properties called the liquid crystalline state.

[0063] In the present description, with “polyamides” is meant a polymer comprising amide bonds. There are several types of polyamides, such as aliphatic polyamides, aromatic polyamides or polyphthalamides. Examples are polyamide 11 and polyamide 12.

[0064] In the description, with “PA11 ” is meant polyamide 11 , also known as nylon 11 , according to the structure below:

[0065] PA11 is a type of synthetic polyamide known for its high strength, flexibility, and chemical resistance. In the description, with “PA12” is meant polyamide 12, also known as nylon 12, according to the structure below:

[0066] PA12 is a versatile thermoplastic polymer valued for its flexibility, impact resistance, and chemical stability.

[0067] In the present description, with “aliphatic polyketone” is meant a polyketone comprising aliphatic comonomer(s) (POK), such as carbon monoxide, ethylene, and propylene monomers, according to the structure below:

[0068] In the present description, with “POK” is meant a polyketone polymer that is built from aliphatic comonomers. POKs are a family of thermoplastic polymers comprising polar ketone groups in the polymer backbone. They are prepared by polymerizing carbon monoxide with an olefin as comonomer (e.g., ethylene). POK come in different types depending on 1) the number of comonomers and; 2) the types of comonomer(s). When one olefin comonomer is used the term copolymer is often used and when two olefin comonomers are used the term terpolymer is often used.

[0069] The two most common types of aliphatic POK are copolymers built from the monomers carbon monoxide and ethylene (R being hydrogen), and terpolymers built from the monomers carbon monoxide, ethylene, and a second olefin comonomer which can be propylene, butylene (e.g. 1-butene), hexylene, octene, or dodecene (in the comonomers, R is methyl, butyl, hexyl, octyl, or dodecyl).

[0070] POKs have polar ketone groups in the polymer backbone and the presence of these ketone groups provides strong attraction between polymer chains, which increases the material’s melting point to about 260 °C for the copolymer (having carbon monoxide and ethylene monomers) and about 220 °C for the terpolymer (having carbon monoxide, ethylene, and propylene monomers). In the present description, with “aromatic polyetherketone” is meant a polyetherketone comprising comonomer(s) having aromatic groups (PEK). PEKs are polymers whose backbone contain alternating ketone (R-CO-R) and ether (R-O-R) functionalities. The most common are PAEKs.

[0071] In the present description, with “PAEK” is meant polyaryletherketone. This is a family of PEK whose molecular backbone contains alternately ketone (Aryl-CO-Aryl) and ether groups (Aryl-O-Aryl), wherein Aryl is a 1 ,4-substutited aryl group. These polymers are semi-crystalline thermoplastics with high-temperature stability and high mechanical strength.

[0072] In the present description, with “PEEK” is meant polyetheretherketone according to the structure below:

[0073] PEEK is a PEK, more specifically of the PAEK family. PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The processing conditions used to mold PEEK can influence the crystallinity and hence the mechanical properties.

[0074] In the present description, with “PEKK” is meant polyetherketoneketone according to the structure below:

[0075] PEKK is also a PEK, more specifically of the PAEK family. PEKK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures.

[0076] In an embodiment of the first aspect of the present invention, the thermoplastic matrix material of the UD barrier tape comprises one or more aromatic polyketones (PEK), such as PEEK and PEKK. Due to the properties of these PEKs, they are suitable for use in reinforced thermoplastic pipes (RTPs).

[0077] In the present description, with “PU” is meant polyurethane, also often abbreviated as PUR. It is a class of polymers composed of organic units joined by carbamate (urethane) links. It can be produced from a wide range of starting materials leading to a variety of polyurethanes with different chemical structures and thus, different properties. An example of a PU is the structure below:

[0078] PU is typically produced by reacting an isocyanate with a polyol (resulting in the polyurethane structure above). Since a polyurethane contains two types of monomers, which polymerize one after the other, they are classed as alternating copolymers. Both the isocyanates and polyols used to make a polyurethane contain two or more functional groups per molecule.

[0079] In the present description, with “PES” is meant polyethersulfone according to the structure below. This is a thermoplastic polymer comprising ether bonds, aromatic rings, and sulfone bonds in the backbone:

[0080] In the present description, with “PEI” is meant polyetherimide. This is a high- temperature thermoplastic polymer just like PEEK. Compared to PEEK, it has a lower impact strength. PEI contains phthalimide and bisphenol A subunits. It has the following structure: In the present description, with “PVC” is meant polyvinylchloride according to the structure below:

[0081] PVC is produced by polymerization of the vinyl chloride monomer (VCM). The presence of the chloride groups gives the polymer very different properties from the structurally related PE.

[0082] In the present description, with “PVDF” is meant polyvinylidene fluoride, being a fluorinated type of polyolefin. It has the following structure:

[0083] PVDF is a thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride.

[0084] In the description, with “PVA” is meant polyvinyl acetate according to the structure below:

[0085] PVA is an aliphatic rubbery synthetic polymer. It is a type of thermoplastic polymer. PVA is prepared by the polymerization of vinyl acetate monomer (free-radical vinyl polymerization of the monomer vinyl acetate).

[0086] In the present description, with “PAN” is meant polyacrylonitrile according to the structure below:

[0087] PAN is a synthetic, semicrystalline organic polymer resin. Almost all PAN are copolymers with acrylonitrile as the main monomer.

[0088] In the present description, with “PC” is meant polycarbonate according to the structure below:

[0089] PC is a group of thermoplastic polymers containing carbonate groups in their chemical structures. The main PC material is produced by the reaction of bisphenol A (BPA) and phosgene (COCI2). An alternative route to produce PC entails transesterification from BPA and diphenyl carbonate.

[0090] In one embodiment, any of the above polymers (polar or non-polar) may be used singly as the matrix of the fibre-reinforced thermoplastic UD barrier tape.

[0091] In an embodiment, the at least one polar polymer is selected from the group consisting of a polyester, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) and liquid-crystal polyester (LCP), a polyamide, such as nylon 11 (PA11) and nylon 12 (PA12), aliphatic polyketone (POK), aromatic polyketone (PEK) such as a polyaryletherketone (PAEK), for example polyetheretherketone (PEEK) and polyetherketoneketone (PEKK), polyurethane (PU), polyether sulfone (PES), polyetherimide (PEI), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyvinyl acetate (PVA), polyacrylonitrile (PAN), polycarbonate (PC), and a combination of two or more thereof, preferably a polyester, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) and liquid-crystal polyester (LCP). In a preferred embodiment, the at least one non-polar polymer is a polyolefin and the at least one polar polymer is a polyester, preferably the at least one non-polar polymer is polypropylene (PP) and the at least one polar polymer is polyethylene terephthalate (PET) or polybutylene terephthalate (PBT).

[0092] In another preferred embodiment, the non-polar polymer to polar polymer volume ratio is from 45:55 tot 55:45. A volume ratio closer to 50:50 produces a co-continuous morphology of the thermoplastic matrix material, which results in a more constant quality of the UD barrier tape.

[0093] In an even more preferred embodiment, the non-polar polymer is polypropylene (PP) and the polar polymer is polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), wherein the non-polar polymer to polar polymer volume ratio is from 45:55 to 55:45, and wherein the viscosity of the thermoplastic matrix material is at most 70 Pa s.

[0094] The thermoplastic matrix material may have: a melt mass-flow rate (MFR) of at least 60 g / 10min, preferably at least 100 g / 10min, more preferably at least 150 g / 10min, most preferably between 60 and 200 g / 10min measured at 240 °C with a load of 2.16 kg according to ASTM D1238-23; and / or a viscosity of at most 100 Pa s, preferably at most 70 Pa s, measured about 20 °C above the melting temperature of the composition according to ISO 6721.

[0095] A thermoplastic matrix material having such properties makes it extremely suitable for the application in UD barrier tape.

[0096] The MFR of a polyamide or polyester can be adjusted by controlling the moisture present in the melt by selecting the drying time of the polar polymer. The MFR of a PP can be adjusted by controlling its molecular weight by 'cracking' of the PP. In order to blend the non-polar and the polar polymers, each of said non-polar and polar polymers must have a viscosity of from about 50 to about 100 Pa s, measured at 240 °C according to ISO 6721 .

[0097] Barrier coating

[0098] In the present description, with “barrier coating” is meant an in-plane layer of a polymer material with platelets embedded in it that functions as a barrier against chemicals, such as CO2, O2, H2O, H2S, and CH4. With “in-plane” is meant a tight, flat stacking of platelets or fillers in the barrier coating with overlaps. Said polymer is preferably the same or a similar polymer as used in the thermoplastic matrix and / or inner liner and / or outer jacket or compatible with the polymer as used in thermoplastic matrix and / or inner liner and / or outer jacket.

[0099] In an embodiment, the barrier coating comprises platelets in an amount of between 20 and 90 wt.%, preferably between 50 and 90 wt.%, more preferably between 70 and 90 wt.%, based on the total weight of the barrier coating. In a barrier coating comprising platelets in these amounts has the effect that the platelets become more and more confined with each other such that they stay highly oriented to accommodate neighbouring platelets, thereby further increasing the parallel and staggered orientation. This will result in improved protection of the reinforcing layer of the UD barrier tape against the hazardous fluids and gaps between neighbouring platelets within a single platelet layer are closed by another overlapping platelet layer.

[0100] Generally, the amount of platelets is selected such that the platelets disperse to achieve the desirable ink suspension, and such that the resulting suspension facilitates a substantially even distribution of the platelets onto the reinforcing fibrecontaining UD thermoplastic polymer matrix. In one embodiment, the amount of platelets dispersed in the ink generally ranges from about 0.5 wt.% to about 2 wt.% of the total weight of the ink suspension.

[0101] The barrier coating may cover at least 70%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, most preferably at least 99%, of the first side and / or the second side of the UD barrier tape. This has the benefit that it improves the protection of the reinforcing layer of the UD barrier tape to gases and fluids that diffuse through the respective thermoplastic inner liner and / or thermoplastic outer jacket. With the coverage is meant the percentage of the surface area of the tape that is covered with platelets and is a rate for the amount of gaps left between the platelets. Fully covered and thus having no gaps left is 100%.

[0102] In an embodiment, the barrier coating is present on both the first side and the second side of the UD barrier tape. The skilled person will understand that the edges of the tape are also covered by the barrier coating.

[0103] Covering both sides of the UD barrier tape provides protection to the reinforcing layer of the UD barrier tape against chemicals that diffuse through the thermoplastic inner liner towards the reinforcing layer (thus from centre to periphery) and also against chemicals that diffuse through the thermoplastic outer jacket towards the reinforcing layer (thus from periphery to centre).

[0104] The barrier coating may have a thickness of between 0.01 (10 nm) and 50 pm, preferably between 0.1 and 25 pm, more preferably between 1 and 10 pm, and / or wherein the ratio between a thickness of the UD tape to a thickness of the barrier coating (tuo : tBM) is between 3,000: 1 and 6:1 , preferably between 300:1 and 12: 1 , more preferably between150:1 and 30:1. Such a thickness is beneficial because the thickness of the UD barrier tape is only slightly increased, such that there is no significant difference between the thickness of an RTP comprising a conventional UD tape and an RTP comprising a UD barrier tape.

[0105] Platelets

[0106] In the present description, with “platelets” is meant a flat, plate-like structure of one or more layers of a specific material, such as graphene. For example, graphene platelets refer to one or more sheets or layers of carbon atoms arranged in a hexagonal lattice.

[0107] In an embodiment, the platelets in the barrier coating are selected from the group consisting of graphene, graphene oxide, graphite, clay - such as montmorillonite, bentonite, nontronite, beidellite, wolkonskoite, hectorite, saponite, sepiolite, stevensite, sauconite, sobokite, swinfordite, silicic acid, phyllosic acid zirconium phosphates, dichalcogenides, polyhedral oligomeric silsesquioxane, potassium titanate, kanemite, macatite, octosilicate, magadiite, kenyaite, mica, vermiculite, illite, ledikite, tubular attapulgite, brucite, gibbsite, berlinite, vantasselite, talc, serpentine, chrysotile-asbestos, revdinskite, palygorskite, muscovite, phlogopite, biotite, glauconite, pennite, clinochlor, kaolinite, chrysocollonite-garnierite, chrysocollonite- garnierite, chrysocollonite-garnierite - aluminium flakes, aluminium nitride, boron nitride, carbon nanotubes and nanoparticles, barium sulphate nanoparticles, silica nanoparticles, and one or more combinations thereof, preferably graphene and clay.

[0108] The graphene platelets provide a more effective barrier against H2O. It provides hydrophobicity to the barrier coating and it is a high barrier to H2and He as well. The graphene platelets further provide electrical conductivity making it suitable for use in ink jet printing in flexible electronics. The graphene platelets can dissipate static electricity. It is known that the flow of liquids in a non-metallic pipe leads to the build up of static charge and with flammable gases, this poses and explosion risk through sparking.

[0109] The clay platelets are an excellent barrier against O2and CO2.

[0110] In an embodiment, the platelets have an interlayer distance of between 5 and 200 nm. Such an interlayer distance gives a denser alignment of the platelets in the barrier coating that further improves the impermeability of the barrier layer to gases. The interlayer distance is determined using transmission electron microscopy (TEM).

[0111] The platelets may have a length of between 0.5 and 200 pm and width of between 1 and 200 pm. The aspect ratio is the ratio between the length of the platelets and the width of the platelets. Such an aspect ratio makes it more difficult for fluids to diffuse through the barrier coating, thereby resulting in improved protection of the reinforcing layer of the UD barrier tape. The platelets may have a thickness of between 0.35 and 100 nm. The thinner the thickness of the platelets, the better the thickness of the barrier coating can be controlled.

[0112] Reinforcing fibres

[0113] Reinforcing fibres are dispersed in the thermoplastic material such that they are unidirectionally aligned in the thermoplastic material in order to obtain the fibre- reinforced thermoplastic UD barrier tape according to the first aspect of the invention. The unidirectionally aligned reinforcing fibres may be selected from the group consisting of glass fibres, carbon fibres, basalt fibres, ceramic fibres, aramid fibres, hemp fibres, flax fibres, sisal fibres, and one or more combinations thereof, preferably glass fibres, carbon fibres, and / or basalt fibres. This broad range of types of fibres that are suitable for reinforcing the thermoplastic matrix material provides extra flexibility to the manufacturing process and makes it less dependent on one or a few types of fibres.

[0114] In the present description, with “unidirectionally aligned reinforcing fibres” is meant that substantially all fibres, preferably all fibres, are aligned in a single direction. In the present description, with “single direction” is meant the longitudinal direction of the UD barrier tape, i.e., the machine direction in which the UD barrier tape is manufactured.

[0115] In the present description, with “parallel aligned continuous multifilament strands” is meant that the reinforcing fibres are continuous strands of fibres that are positioned in parallel to each other in the longitudinal direction of the UD barrier tape. The fibres in the fibre-reinforced thermoplastic UD barrier tape are generally supplied as a plurality of continuous, very long filaments, and can be in the form of strands, rovings, or yarns.

[0116] A filament is an individual fibre of reinforcing material. A strand is a plurality of bundled filaments. Yarns are collections of strands, for example strands twisted together. A roving refers to a collection of strands wound into a package.

[0117] In the present description, with “continuous” in connection with fibres, filaments, strands, yarns, or rovings is meant that the fibres, strands, filaments, yarns, or rovings generally have a significant length. However, it should not be understood to mean that the length of the fibres, strands, filaments, yarns, or rovings is perpetual or infinite. Continuous fibres, such as continuous filaments, strands, yarns, or rovings have a length of more than 100 mm, preferably more than 1000 mm, depending on the length of the of the UD barrier tape. Most preferably, the fibres have the same length as the UD barrier tape.

[0118] In the present description, with “reinforcing fibres” is meant fibres that are added to the thermoplastic matrix material with the purpose of improving the matrix material’s strength. In other words, fibres that reinforce the matrix material.

[0119] In the present description, with “glass fibres” is meant a material that consists of numerous extremely fine fibres of glass. Thin strands of silica-based or other formulation glass are extruded into many fibres with small diameters suitable for textile processing.

[0120] The most common type of glass fibre is E-glass, which is alumino-borosilicate glass. E-glass has less than 1 wt.% alkali oxides and is mainly used for glass-reinforced plastics. Other types of glass used are A-glass (alkali-lime glass with little or no boron oxide), E-CR-glass (Electrical / Chemical Resistance; alumino-lime silicate with less than 1 wt.% alkali oxides, with high acid resistance), C-glass (alkali-lime glass with high boron oxide content, used for glass staple fibres and insulation), D-glass (borosilicate glass, named for its low dielectric constant), R-glass (alumino silicate glass without MgO and CaO with high mechanical requirements as reinforcement), and S-glass (alumino silicate glass without CaO but with high MgO content with high tensile strength).

[0121] In the present description, with “carbon fibres” is meant carbon fibres (alternatively OF or graphite fibre) having a diameter of about 5 to 10 micrometres that are composed mostly of carbon atoms, arranged in a graphitic structure. Specifically, the graphene planes are oriented parallel to the carbon fibre’s axis. Carbon fibres have several advantages: high stiffness, high tensile strength, high strength to weight ratio, high chemical resistance, high-temperature tolerance, and low thermal expansion. However, they are relatively expensive compared to similar fibres, such as glass fibres and basalt fibres.

[0122] In the present description, with “basalt fibres” is meant fibres that are produced from basalt rocks by melting them and converting the melt into fibres. Basalt fibres, or more specifically basalt continuous fibres, can be used for the production of reinforcing materials and composite products. Basalt fibres are made from a single material, crushed basalt, from a carefully chosen quarry source. Basalt of high acidity (over 46% silica content) and low iron content is considered desirable for fibre production. Unlike with other composites, essentially no materials are added during its production: the basalt is simply washed and then melted. Basalt fibres are fire resistant and do not burn, which makes them very suitable as a reinforcing material in a fibre-reinforced thermoplastic UD barrier tape that requires good flame retardancy.

[0123] Furthermore, when basalt fibres are used to strengthen polymers, its composites have good strength, high working temperature range, good chemical resistance, excellent heat and sound insulation properties and low water absorption. In addition, basalt fibres are easy to process, environmentally friendly, and relatively cheap.

[0124] In the present description, with “ceramic fibres” is meant fibres that are smalldimension filaments or threads composed of ceramic material, usually alumina and silica, used in lightweight units for electrical, thermal, and sound insulation. Mainly, ceramic fibres are of two types: ceramic oxide fibres and ceramic non-oxide fibres.

[0125] Ceramic oxide fibres mostly consist of alumina (AI2O3) and alumina-silica (AI2O3-SiO2) mixtures and are generally used for high-temperature applications due to their high melting points. Ceramic oxide fibres are used both as insulation and as reinforcement material. The mostly known examples for oxide ceramic fibres are composed of oxides such as silica (SiO2), mullite (3AI2O32SiO2), alumina (AI2O3), and zirconia (ZrO2) having different characteristic properties. Production of non-oxide fibres is difficult due to their high melting points and resistance to densification. Oxidation resistance tends to be their main deficiency. Examples are silicon carbide-based fibres. Silicon carbide (SiC) fibres have an excellent combination of high strength, modulus, and thermal stability, including good oxidation resistance and mechanical properties (compressive-tensile strength) at high temperatures. Silicon carbide-based fibres are generally applied as continuous fibre in ceramic matrix. This type of ceramic matrix composites (CMCs) is used in hot section of engines for power, etc.

[0126] In the present description, with “aramid fibres” is meant aromatic polyamide fibres, which are a class of heat-resistant and strong synthetic fibres. The chain molecules in the fibres are highly oriented along the fibre axis. As a result, a higher proportion of the chemical bond contributes more to fibre strength than in many other synthetic fibres. Aramids have a very high melting point (>500 °C). Aromatic in the name refers to the presence of aromatic rings of six carbon atoms. In aramids these rings are connected via amide linkages each comprising a CO group attached to an NH group. Aramids are divided into two main types according to where the linkages attach to the rings: para-aramids and meta-aramids. Numbering the carbon atoms sequentially around a ring, para-aramids have the linkages attached at positions 1 and 4, while meta-aramids have them at positions 1 and 3. That is, the attachment points are diametrically opposite each other in para-aramids, and two atoms apart in metaaramids.

[0127] In the present description, with “hemp fibres” is meant vegetable fibres that are generally based on arrangements of cellulose, often with lignin, derived from the hemp plant under the species Cannabis.

[0128] In the present description, with “flax fibres” is meant vegetable fibres that are extracted from the bast or skin of the stem of the flax plant (Linum usitatissimum L).

[0129] In the present description, with “sisal fibres” is meant vegetable fibres that are derived from the plant under the species Agave Sisalana. Whichever the reinforcement fibre chosen, the fibres should have a suitable size applied to them. The size is selected to protect the fibre during handling, but also to provide good adhesion to the thermoplastic matrix polymer, thereby increasing the strength of the UD barrier tape. The size on the fibre has to be selected according to the thermoplastic matrix material.

[0130] In the present description, with “distribution of fibres throughout the tape” is meant the distribution of the fibres over the width of the fibre-reinforced thermoplastic UD barrier tape transverse to the longitudinal direction (i.e., machine direction) of the fibres. A relatively uneven distribution may result in the UD barrier tape having undesirable and / or unpredictable structural characteristics. A relatively even distribution means that the continuous unidirectionally aligned fibres are evenly distributed in the UD barrier tape and provides a UD barrier tape having desirable and / or predictable structural characteristics. Preferably, the distribution of the fibres is relatively even.

[0131] In the present description, with “close to surface” is meant that the average distance between the top or bottom surface of the fibre-reinforced thermoplastic UD barrier tape and the fibres embedded in the fibre-reinforced thermoplastic UD barrier tape is between 5 and 20 % of the thickness of the fibre-reinforced thermoplastic UD barrier tape.

[0132] Preferably, the unidirectionally aligned reinforcing fibres have a diameter of between 4 and 20 pm, preferably between 8 and 13 pm and / or a length of at least 100 mm, preferably at least 1000 mm. The fibres of this specific diameter and / or length provide sufficient strength to the UD barrier tape over the whole length (in the longitudinal direction) of the UD barrier tape. Furthermore, it also allows the preparation of a fibre- reinforced thermoplastic UD barrier tape having a relatively low thickness.

[0133] Preferably, the unidirectionally aligned reinforcing fibres are aligned parallel to each other in the longitudinal direction. This improves the strength of the UD barrier tape over the whole length (in the longitudinal direction) of the UD barrier tape while maintaining the flexibility of the UD barrier tape. In the present description, with “longitudinal direction” is meant the machine direction in which the UD barrier tape is produced.

[0134] In another embodiment, the UD barrier tape comprises between 10 and 74 wt.% of the unidirectionally aligned reinforcing fibres, between 25 and 89 wt.% of the thermoplastic matrix material, between 1 and 10 wt.% of the at least one compatibilizer, and between 0 and 10 wt.% of at least one additive, based on the total weight of the UD barrier tape. The higher the fibre content in the UD barrier tape, the higher the performance of the UD barrier tape. However, a too high fibre content may lead to insufficient impregnation and / or problems with the mechanical strength of the UD barrier tape, e.g., the integrity of the UD barrier tape becomes poor, resulting in the UD barrier tape falling apart.

[0135] Additives

[0136] The thermoplastic matrix material of the UD barrier tape may comprise one or more additives. The one or more additives is selected from the group consisting of compatibilizers, adhesion-enhancing copromotors, stabilizers, impregnation agents, lubricants, antioxidants, and flame retardants.

[0137] In the present description, with “additives” is meant an additive for the thermoplastic polymers used that may be present in the thermoplastic matrix material. Additives are often used to improve the properties of the thermoplastic polymers. Examples include compatibilizers and stabilizers.

[0138] In the present description, with “compatibilizers” is meant an additive that aids in the compatibility between different thermoplastic polymers. Compatibilizer are polymers that have functional groups similar to both non-polar and polar polymers. Without them, immiscible polymers in the molten state when shearing is stopped would segregate into two layers like oil and water.

[0139] Block copolymers comprise of two or more homopolymer subunits linked by covalent bonds. They are made up of blocks of different polymerized monomers. Examples are diblock copolymers, which have two distinct blocks (e.g., ~A-A-A-A-A-B-B-B-B-B~), and triblock copolymers, which have three distinct blocks (e.g., ~A-A-A-A-B-B-B-B-C- C-C-C-).

[0140] Graft copolymers are segmented copolymers with a linear backbone of one chain segment and randomly distributed branches of another chain segment, which is structurally different from the former chain segment forming the linear backbone.

[0141] A terpolymer is a copolymer that contains three types of repeat units. Hence, a terpolymer is formed from the polymerization of three different monomers. The resulting polymer chain contains repeating units of all three monomers. An example is a random terpolymer of ethylene, acrylic ester, and glycidyl methacrylate.

[0142] In the present description, with “adhesion-enhancing copromotors” is meant a substance, being a copromotor, that enhances the adhesion of the thermoplastic matrix material and the reinforcing fibres dispersed within the thermoplastic matrix material.

[0143] In the present description, with “stabilizers” is meant an additive that aids in the prevention of heat, oxidation, and chemical degradation of the fibre-reinforced thermoplastic composite. Examples include phenolic alkylene dicarboxylates that provide stabilization against degradation with a reduced tendency to yellow discoloration and improved melt, processing performance over an extended period of time, aluminium phosphate or aluminium silicate treated with polyethylene glycol that improves the colour stability of the material, and zinc oxide or lead stabilizer that also improves the colour stability and furthermore improves the thermal stability of POK and its processing temperature window.

[0144] In the present description, with “impregnation agent” or “impregnating agent” is meant a material that is compatible with the thermoplastic polymer to be reinforced and may even be soluble in said polymer. The skilled person can select suitable combinations based on general knowledge, and may also find such combinations in the art. Suitable examples of impregnating agents include low molar mass compounds, for example low molar mass or oligomeric polyurethanes, polyesters such as unsaturated polyesters, polycaprolactones, polyethyleneterephthalate, poly(alpha-olefins), such as highly branched polyethylenes and polypropylenes, polyamides, such as nylons, and other hydrocarbon resins.

[0145] Preferably, the impregnating agent is non-volatile, and / or substantially solvent-free. In the context of the present invention, non-volatile means that the impregnating agent has a boiling point or range higher than the temperatures (about 230-240 °C) at which the polymer’s melt impregnation is conducted over the reinforcing fibres. In the context of present invention, “substantially solvent- free” means that impregnating agent contains less than 10 wt.% of solvent, preferably less than 5 wt.% of solvent based on the impregnating agent. In a preferred embodiment, the impregnating agent does not contain any organic solvent.

[0146] In the present description, with “lubricants” is meant a material that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. Examples are stearamides and stearates, such as EBS, calcium stearate or magnesium stearate.

[0147] In the present description, with “antioxidants” is meant a compound that inhibits oxidation, a chemical reaction that can produce free radicals. The antioxidant additive may comprise one, two or more phenolic groups. These phenolic antioxidant additives may be sterically hindered phenolic additives. Examples are tris(2,4-di-tert- butylphenyl)phosphite, commercially available as Irgafos 168, and octadecyl-3-[3,5- di-tert-butyl-4-hydroxyphenyl]propionate, available from BASF as Irganox 1076.

[0148] In the present description, with “flame retardants” is meant a material that is activated by the presence of an ignition source and is intended to prevent or slow the further development of ignition by a variety of different physical and chemical methods. They may be added as a copolymer during the polymerisation process, or later added to the polymer at a moulding or extrusion process or applied as a topical finish. Examples are minerals such as aluminium hydroxide (ATH), magnesium hydroxide (MDH), Huntite and hydromagnesite, organohalogen compounds such as organochlorines, organobromines, and polymeric brominated compounds, organophosphorus compounds such as organophosphates, phosphonates, and phosphinates, and organic compounds such as carboxylic acid and dicarboxylic acid.

[0149] Unidirectional (UD) barrier tapes

[0150] The fibre-reinforced thermoplastic UD barrier tape may have a width of at least 2 cm, preferably between 5 and 20 cm, more preferably between 8 and 15 cm and / or has a thickness of between 0.10 and 0.80 mm, preferably between 0.15 and 0.50 mm, more preferably between 0.25 and 0.35 mm. A UD barrier tape of these dimensions provides optimal balance between flexibility and applicability and strength. This makes them particularly suitable for the production of complex component shapes. Furthermore, the low thickness of the UD barrier tape allows that the reinforced thermoplastic pipes only increase a very small amount in thickness.

[0151] In the present description, with “unidirectional (UD) tape” is meant a tape that comprises endless fibre-reinforced tapes of different widths with unidirectionally aligned reinforcing fibres. In UD tapes, fibres, such as glass fibres or carbon fibres, are embedded so ideally in a thermoplastic matrix that completely new possibilities arise in the production of components. Despite their low thickness, UD tapes have a high level of stability and are also particularly light. In addition, UD tapes can be processed efficiently and, depending on the combination and additives present, are flame retardant. Furthermore, the UD tape is collected and stored on rolls and hence it can be cut to length and width according to the application. Another important property of thermoplastic UD tape is the possibility of recycling.

[0152] In the present description, with “unidirectional (UD) barrier tape” is meant a tape similar to a conventional UD tape as described above with the difference that the UD barrier tape also comprises a barrier coating comprising platelets, whereas a conventional UD tape does not comprise such a barrier coating.

[0153] Conversion of the UD barrier tape matrix from thermoplast to thermoset For some applications, it is desirable to convert the thermoplastic material to a thermoset material. This can for example be done via heat-induced cross-linking. The cross-linking of the thermoplastic matrix material is performed after production (shaping or moulding) of the article comprising the fibre-reinforced thermoplastic UD barrier tape.

[0154] In an embodiment, the UD barrier tape comprises at least one cross-linked non-polar polymer and / or at least one cross-linked polar polymer. This is beneficial, as the UD barrier tape is more resistant to creep, and this allows for the use above the lowest melting point of the polymers in the UD barrier tape for short periods of time.

[0155] Method of manufacturing fibre-reinforced thermoplastic UD barrier tape

[0156] The UD barrier tape may be manufactured via inkjet printing or screen printing using a paste. In an embodiment, the method comprises inkjet printing in a roll-to-roll process, flexo printing, rotogravure printing, or Meyer bar coating and comprises the steps of:

[0157] 1) providing the UD tape; and

[0158] 2) applying the ink on the first side and / or the second side of the UD tape by inkjet printing in a roll-to-roll process, flexo printing, rotogravure printing, screen printing, or Meyer bar coating to provide the UD barrier tape on which the barrier coating is present on the first side and / or the second side of the UD tape.

[0159] Applying the barrier coating by means of inkjet printing allows coating of specific parts of the UD tape with high accuracy. It may be desirable to only apply the barrier coating on specific parts or sides of the UD tape, for example to reduce costs.

[0160] The method of the above-given embodiment may have an additional step of:

[0161] 1 b) prior to step 2), surface treating with a corona discharge, plasma, or ultrasonic the UD tape provided in step 1) on the first side and / or the second side to provide a surface-treated UD tape. Depending on the UD tape’s matrix polymer’s surface energy, a pre-treatment of the tape’s surface maybe needed to allow spreading of the ink or the coating containing the platelets, so that they do not collect into droplets or islands.

[0162] The method of inkjet printing may further comprise the step of:

[0163] 3) heat curing or ultraviolet curing the barrier coating applied in step 2) to bond the barrier coating to the UD tape, or surface-treated UD tape, to provide a consolidated UD barrier tape.

[0164] A consolidation step provides additional strength to the UD barrier tape.

[0165] The ink containing platelets of graphene, metallic flakes or clays etc. can also be applied to the UD tape by dip coating from a roller based applicator, or by spray coating.

[0166] The ink or paste dispersion comprises platelets and an aqueous or organic carrier with a binder (monomer). The binder bonds the platelet materials to the desired substrate. The binder can be subsequently polymerized (after coating) by heating below the melting point of the thermoplastic matrix material of the UD tape, or by ultraviolet, to provide the UD barrier tape on which the barrier coating is fixed on the first side and optionally the second side of the UD tape. The binder in which the platelets are suspended can be an ultraviolet or heat cross-linkable monomer according to formulations known in the art. The heat-curable binder is chosen according to its curing temperature, and this will be determined by the melting temperature of the UD tape’s matrix. For example, if the matrix of the UD tape is a low melting polymer like PE or PP, the heat-curable monomer in the ink or paste would be selected to cure at ~120 °C; or an ultraviolet curing monomer might be used. If the matrix is a high-melting polymer like a polyimide, then the heat curable monomer would cure at a higher temperature. Further, the binder for the graphene or other platelets maybe customised by those skilled in the art so that it is resistant to acids and alkalis under hot conditions (90-130 °C). Further, a thermoplastic can be included in the ink or paste formulation such that it aids in lamination of the UD tape to itself or other materials. An example of a commercial graphene ink is Dycotec DM-GRA-9003 (supplied by Dycotec Materials, Caine, the UK). It is an aqueous based graphene ink designed for either inkjet printing or spray application. The ink is designed to be cured at 120 °C. The graphene may be single layer (pristine graphene) or a platelet of a few layers. The ink is based not on pristine graphene, but on few layer graphene (< 3 nm thick) of lateral diameter <1 pm. The solids content is 1-2% and the ink’s viscosity is >8 cP at 21 °C. There is an acrylic heat-curable monomer included which allows the graphene layers to be consolidated and adhered to the substrate, in this case the UD tape.

[0167] Graphene pastes, which have a higher viscosity, can also be used with dilution if needed, and any suitable applicator can be used.

[0168] Inks vary in solid contents. An ink with 10 wt.% of graphene in water will have a viscosity of ~600 cP.

[0169] Apart from inkjet printing, other methods to apply the ink is based on flexo printing, rotogravure printing, or Meyer bar coating. Flexo printing is used for non-porous substrates like food packaging films and it is suitable for printing large areas of solid colour. The UD tape is a non-porous substrate. Rotogravure printing is also a rollbased printing process which is good for covering large areas, of a sheet substrate such as a polymer film or paper sheet. Normally in gravure printing which is used to print images in printing presses, ‘solid’ areas are actually printed as dots, but the ink and substrate combination can be set up to allow solid areas (ink covered) to flow together and join.

[0170] In Meyer bar coating, rods with windings of wire are used to apply coatings to substrates. The web substrate (UD tape in this case) would be moved through the coating machine with motorised rollers, a coating roll picks up the ink from a pan and applies it to the web. A wire wound rod (known as a Meyer bar which functions as an ink metering rod) doctors the ink to the desired thickness. Another roller moves the web to the next step of the manufacturing process (heat fixation of the ink to the UD tape). Further, the deposition of the graphene on the UD tape need not be based on ink or liquid dispersions. Graphene can be deposited by CVD (Chemical Vapour Deposition). CVD-deposited graphene is densely packed. Although a batch CVD coating is often used for laboratory work, continuous roll-to-roll coating is possible. See for example: Erik S. Polsen, Daniel Q. McNerny, B. Viswanath, Sebastian W. Pattinson & A. John Hart, ‘High-speed roll-to-roll manufacturing of graphene using a concentric tube CVD reactor’, Scientific Reports | 5:10257 | DOI: 10.1038 / srep10257. The carbon producing feedstock is gases such as ethylene, methane etc. Copper or other transition metals are used as the substrate because such metals acts as catalyst for conversion of the feedstock to the graphene. The graphene coating on copper then has to be transferred to the plastic sheet, and batch processes are described in the scientific literature. However, the technology also exists to make graphene by CVD in a roll-to-roll process on a copper substrate, and then to transfer the graphene to plastic film (also by a roll- to-roll process). The same technology can be used to coat a UD tape from a roll, with graphene made by a CVD process.

[0171] Graphene can also be made by reducing a coating of graphene oxide, thermally or chemically. Graphite oxide can be produced by the method of Hummers, W. S. & Offeman, R. E. Preparation of graphitic oxide. J. Am. Chem. Soc. 80, 1339-1339 (1958). The Graphite oxide flakes have lateral widths of 0.2-20 pm. The flakes can then be suspended in water. The suspension can then be used to coat the plastic film (which may need to treated with corona discharge). The suspension can be coated onto the UD tape by rod-coating (Meyer bar) or spray-coated. Next, the graphite oxide coating on the plastic film can be chemically reduced to graphene by immersing it in a reducing agent such as an aqueous hydrogen iodide or ascorbic acid (Vitamin C) solution, as described in Y. Su V.G. Kravets, S.L. Wong, J. Waters, A.K. Geim & R.R. Nair, ‘Impermeable barrier films and protective coatings based on reduced graphene oxide’ (NATURE COMMUNICATIONS | 5:4843 | DOI: 10.1038 / ncomms5843 | www.nature.com / naturecommunications). The same method can be used to coat a UD tape with graphene oxide and then the graphene oxide is reduced to graphene using reducing agents such as HI, ascorbic acid or other. Again, an aspect of the UD tape is to produce a fully bonded tape, especially for RTP systems. This involves in heat pressing the barrier UD tapes minimising the randomising of the orientation of the graphene.

[0172] One aspect of this invention is a UD tape with a barrier coating made of densified platelet materials, for example, graphene and clays. Previous inventions, for example WO2014 / 063009 A1 (Multi-functional high performance nanocoatings from a facile coassembly process) describes application of a coating of clay platelets and a method of densification and fixation of these on plastics, glass, wood, paper, ceramic and metal surfaces, and any combination of the above. In general, any random combination of the above materials is implied as being equally effective. However, the UD tape is a special construction which has an ABA layering, where the outer surface layers of the UD tape (A layers) comprise substantially the matrix thermoplastic material and a relatively low amount of reinforcing fibres, and the layer in between the A layers (middle layer B) comprises a higher amount of the reinforcing fibres are concentrated. Typically, in a 300 pm tape, the A layer is the matrix polymer which is 10-50 pm thick. The A layer is often asymmetric with one side being thicker than the other. The glass fibres are typically concentrated in a middle layer B, which is of course the majority of the cross section. In this invention, the UD barrier tape does not have a stand-alone application like a plastic barrier film envisaged in W02014 / 063009 A1. The UD tapes will be stacked and consolidated into a laminate with a temperature slightly above the melting point of the matrix polymer. The arrangement of the glass fibres below the skin of the matrix plays an essential role in preventing the barrier platelet layers disorienting, sinking through and mixing throughout the entire volume of the laminate; if the latter occurs, it lowers the barrier and it becomes equivalent to extrusion of a polymer with barrier platelets. If a set of unreinforced plastic films or plastic sheets are coated with platelets, as envisaged in W02014 / 063009 A1 , and this set is stacked and compression moulded, there would be substantial opportunity for dis-orientation of the platelets throughout the entire volume. In contrast, the presence of continuous fibres in the core of the tape prevents the barrier layer from being disoriented substantially when the UD tape layers is moulded into a laminate. This is not anticipated in W02014 / 063009 A1. As for graphene, the binders for clay platelets depends on the type and chemistry of the platelet. An example is described in W02014 / 063009 A1 , ‘Multi Functional High Performance Nanocoatings from a facile co-assembly process’, by Luyi Sun and F. Ding; and in F. Ding et al., ‘Biomimetic nanocoatings with exceptional mechanical, barrier, and flame-retardant properties from large-scale one-step coassembly’, Science Advances 2017; 3:e1701212. See also W02014 / 063009 A1 . Polyvinyl alcohol is added to exfoliated clay platelets in an aqueous medium with glutaraldehyde and HCI catalyst to crosslink the clay platelets and the polyvinyl alcohol after coating the plastic sheet. After coating the plastic sheet, the clay platelets are oriented in a planar orientation with a densified arrangement when the loading of the platelets in the coating is high (50 wt.% or higher). Such a method can be applied to make the UD barrier tape of the invention.

[0173] In an embodiment, a method of coating a substrate includes applying a coating composition as described above to a substrate and curing the coating composition. The coating composition may be applied using any process to apply liquid coatings, such as a dip coating process, a spray coating process, a spin coating process, a liquid jet printing process, or 3D printing process. In an embodiment, a force is applied to the coating composition prior to curing the coating composition, wherein the applied force causes at least a portion of the nanoplatelet materials to become aligned. The applied force may be any physical / chemical force, such as a gravitational force, a mechanical force or a centrifugal force. In some embodiments, the coating composition includes a cross-linking compound. Curing the coating composition may include initiating a cross-linking reaction between the cross- linking compound and the binder and / or nanoplatelet materials. The cross-linking reaction may be thermally initiated, chemically initiated, or initiated by radiation, such as UV light.

[0174] Many different processes may be used to apply the nanoplatelet composite coating composition to the substrate. Dip coating may be used to apply the nanoplatelet composite coating composition to the substrate. In dip coating a substrate is immersed in the nanoplatelet composite coating composition. The substrate remains for a time sufficient to ensure that the substrate has been coated with the nanoplatelet composite coating composition. The substrate is then removed from the nanoplatelet composite coating composition leaving a film of the nanoplatelet composite coating composition on the substrate, with the excess liquid draining from the substrate or removed by a tool. After removal from the nanoplatelet composite coating composition the coated substrate may be passed into a curing chamber where solvent from the nanoplatelet composite coating composition is removed and any final curing processes may be performed.

[0175] In an embodiment, a roll of material to be coated is passed into a container that includes the nanoplatelet composite coating composition. A series of rollers may be used to ensure that the film is maintained within the nanoplatelet composite coating composition to allow the film to be sufficiently coated. The film is drawn vertically from the nanoplatelet composite coating composition to allow the film to be vertically drained of excessive composition. Maintaining the film in a vertical position also helps to align the nanoplatelet material due to gravitational forces and flow force applied to the nanoplatelet materials. The film may be carried into a curing chamber where heat and / or UV radiation is applied to the film to cure the binder and remove excessive solvent (e.g., by heat assisted evaporation). The coated tape may be removed from the chamber and collected for use. If needed, the coating process can be repeated.

[0176] Other process may be used to apply the nanoplatelet composite coating composition to the substrate. Other processes include, but are not limited to, spray coating processes, spin coating processes, liquid jet printing processes, and 3D printing processes.

[0177] While the method of applying the low permeability platelets to form the UD barrier tape might be based on known technologies, according to one aspect of this invention, the coated ~300 pm UD tapes are stacked together and then consolidated by melting under pressure and cooling under pressure. This in effect yields a laminate where the barrier layers of platelet material are periodically stacked at ~300 pm intervals. It is important to realise that the platelets layers are not randomly distributed through the volume of tape and the laminate. This is assured in the Invention because of the reinforcement fibres which are about 20-50 pm below the surface of the tape; these prevent the platelets in the molten matrix material to randomise substantially during consolidation of the tapes into a laminate. While the laminates used in the Examples might be flat, the laminate of tapes in a RTP will be curved, but the platelet layers will be demarcated at ~300 pm intervals (or intervals corresponding approximately to the tape thickness.

[0178] The gas barrier RTP need not be based on coatings of graphene inks, but it could be based on clay platelets, or metallic flakes or other platelet materials. Metallic flakes are not preferred for UD barrier tapes specifically used for RTP due to the corrosive gases, which would cause corrosion and evolution of hydrogen.

[0179] Use

[0180] In an embodiment of the third aspect of the present invention, the fibre-reinforced thermoplastic UD barrier tape according to the first aspect or manufactured according to the second aspect is used for an RTP configured for transporting hydrocarbon fluids. In the present description, with “fluids” is meant liquids, such as water, and gasses, such as butane.

[0181] Applications

[0182] In the present description, with “reinforced thermoplastic pipe (RTP)” is meant a multilayer pipe of thermoplastic material that is reinforced. Other names used are Flexible Composite Pipes, Thermoplastic Composite Pipes, Flexible Flowline, Flexible Line Pipe, Spoolable Reinforced Plastic Line Pipe, Flexible Reinforced Pipe, Reinforced Line Pipe or Spoolable Composites. For offshore use other names include Offshore Flexibles or Flexible Umbilical Risers. According to the present invention, an RTP includes from the centre of the RTP to the periphery of the RTP at least the following layers: a thermoplastic inner liner, a reinforcement layer, and a thermoplastic outer jacket. The outer jacket provides protection of the reinforcing UD barrier tape windings from external mechanical damage.

[0183] In the present description, with “UD barrier tape windings” is meant a fibre-reinforced thermoplastic UD barrier tape that is provided on (wound around) the thermoplastic inner liner. With “fibre-reinforced thermoplastic UD barrier tape” is meant the thermoplastic UD barrier tape provided with fibres that reinforce the thermoplastic UD barrier tape.

[0184] Method of manufacturinq a reinforced thermoplastic pipe (RTP)

[0185] Step 1) and / or step 3) of the method of manufacturing the RTP, i.e., providing the thermoplastic inner liner and applying the thermoplastic outer jacket, may be done by means of extruding. That is, in step 1) a thermoplastic polymer may be extruded into the inner liner and in step 3), an outer jacket may be extruded onto the outer side of the reinforcing layer.

[0186] Step 2), i.e., the one or more steps of winding UD tape layers on the thermoplastic inner liner, may result in the reinforcing layer comprising two or more layers of the UD tape, wherein the barrier coating is positioned on the outermost first side and / or on the outermost second side of two or more layers of UD tape for forming a barrier between the two or more layers of UD tape and the respective thermoplastic inner liner and / or thermoplastic outer jacket.

[0187] There may be many layers of UD (barrier) tape applied to form the reinforcing layer of the RTP. These layers may be applied at winding stations, a set-up to prepare an RTP may comprise a plurality of winding stations, e.g., two to ten winding stations. Each winding station will wind either a UD tape or a UD barrier tape. At each winding station, one or two layers will normally be applied. Each winding station can be seen as a separate winding step.

[0188] During each winding step, the winding station applies one or two layers of UD tape. In case the RTP of the invention comprises two layers, a first winding station will apply one layer of UD barrier tape and the second winding station will apply one layer of UD tape, or a first winding station will apply one layer of UD tape and the second winding station will apply one layer of UD barrier tape. When the RTP comprises four layers, during each of these two winding steps two layers are applied. Preferably, at least four or at least six or at least eight or at least ten winding steps are used, each winding one or preferably two layers of UD (barrier) tape and at least one or two of these winding stations a UD barrier tape is applied and at the remainder of the winding stations a UD tape is applied. In an embodiment, a UD barrier tape is applied at the first and / or the last winding station and a UD tape is applied at the rest of the winding stations.

[0189] Preferably in the optional step 2a), the two or more layers of UD tape are wound on the thermoplastic inner liner such that the layers are under tension and the heating and cooling are performed by applying pressure to the layers of UD tape to establish a strong bond between the reinforcing layer and the thermoplastic inner liner.

[0190] In an embodiment, the RTP may comprise, going from the centre to the periphery, a layer of the thermoplastic inner liner, a layer of the UD barrier tape according to the first aspect of the present invention, a plurality of layers of the UD tape, and a layer of the thermoplastic outer jacket. Wherein “plurality” in this context means two or more, such as four or more, six or more, eight or more or ten or more.

[0191] In yet another embodiment, the RTP may comprise, going from the centre to the periphery, a layer of the thermoplastic inner liner, a plurality of layers of the UD tape, a layer of the UD barrier tape according to the first aspect of the present invention, and a layer of the thermoplastic outer jacket.

[0192] In an even further embodiment, the RTP may comprise, going from the centre to the periphery, a layer of the thermoplastic inner liner, a layer of the UD barrier tape according to the first aspect of the present invention, a plurality of layers of the UD tape, a further layer of the UD barrier tape according to the first aspect of the present invention, and a layer of the thermoplastic outer jacket.

[0193] Typically, each layer of the UD tape, including the layer of the UD barrier tape, is wound helically around the RTP’s inner liner with a gap control (thus not overlapping), for example with a standard pitch.

[0194] In specific cases, overlapping of the tape may be preferred.

[0195] In other specific cases, narrow tapes may be even helically woven over the liner. In the present description, with “thermoplastic inner liner” is meant the inner layer of the RTP that is made of a thermoplastic material, such as PVDF, PPS, POK, PA-11 , PA-12, PE, PP, or mixtures thereof. To prevent damage to the RTP, the thermoplastic inner liner must be made from a material that is resistant to chemicals, such as gaseous or liquid hydrocarbons, which are transported through the RTP. Preferably, the thermoplastic inner liner is also resistant to high temperatures. With “high temperatures” is meant the temperature of the fluids that flow through the RTP, being in the range of above 85 °C, preferably above 90 °C, more preferably above 100 °C, even more preferably above 115 °C.

[0196] In an embodiment, a barrier coating comprising platelets is applied on at least a part of the outer side of the thermoplastic inner liner. Two or more layers of UD (barrier) tape are applied (by winding) on said barrier coated thermoplastic inner liner. Said barrier coating forms a barrier between the two or more layers of the UD (barrier) tape and the thermoplastic inner liner.

[0197] In an embodiment, two or more layers of UD (barrier) tape are applied (by winding) on the thermoplastic inner liner to form a reinforcing layer on the thermoplastic inner liner. A barrier coating comprising platelets is applied on at least a part of the outer side of the reinforcing layer. Said barrier coating forms a barrier between the two or more layers of the UD (barrier) tape and the thermoplastic outer jacket.

[0198] In the present description, with “outer side”” is meant the outer surface facing towards the periphery of the RTP.

[0199] The barrier coating may be applied according to the second aspect of the present invention.

[0200] In the present description, with “reinforcement layer” is meant the layer between the thermoplastic inner liner and the thermoplastic outer jacket that is formed by the fibre- reinforced thermoplastic UD barrier tape. The reinforcement layer provides additional strength to the pipe, hence the name “reinforced thermoplastic pipe (RTP)”. In the present description, with “thermoplastic outer jacket” is meant the outer jacket, layer, or cover of the RTP that is made of a thermoplastic material, such as PDVF, PPS, POK, PA-11 , PA-12, PE, PP, or mixtures thereof. To prevent damage to the RTP, the thermoplastic outer jacket must be made from a material that is resistant to impact and one or more of the following, UV light, high temperatures, water. With “high temperatures” is meant the temperature of the fluids that flow through the RTP, being in the range of above 85 °C, preferably above 90 °C, more preferably above 100 °C, even more preferably above 115 °C.

[0201] In addition, the thermoplastic outer jacket must be made of a material that is sufficiently strong to prevent damage from the surroundings to the RTP.

[0202] Thus, the RTP according to the fourth aspect of the present invention comprises from its centre to its periphery: a thermoplastic inner liner; a reinforcing layer, comprising two or more layers of a fibre-reinforced thermoplastic unidirectional (UD) tape and wherein at least one of said two or more layers of the UD tape is a fibre-reinforced thermoplastic unidirectional (UD) barrier tape having a first side facing towards the centre of the RTP and a second side facing towards the periphery of the RTP, wherein said UD barrier tape comprises a thermoplastic matrix material and unidirectionally aligned reinforcing fibres dispersed within said thermoplastic matrix material, wherein said unidirectionally aligned reinforcing fibres extend in a longitudinal direction of the UD barrier tape, and wherein said UD barrier tape further comprises a barrier coating comprising platelets, wherein said barrier coating is present on at least a part of the first side of the UD barrier tape for forming a barrier between the two or more layers of the UD tape and the thermoplastic inner liner of the RTP and / or wherein said barrier coating is present on at least a part of second first side of the UD barrier tape for forming a barrier between the two or more layers of the UD tape and the thermoplastic outer jacket of the RTP; and a thermoplastic outer jacket. The RTP according to the present invention comprises at least one layer of a UD tape and at least one layer of a UD barrier tape.

[0203] BRIEF DESCRIPTION OF THE DRAWINGS

[0204] The present invention is described hereinafter with reference to the accompanying drawings in which embodiments of the present invention are shown and in which like reference numbers indicate the same or similar elements. The invention is in no manner whatsoever limited to the embodiments disclosed therein.

[0205] Fig. 1 shows a schematic cross-section of part of a reinforced thermoplastic pipe (RTP) according to the present invention.

[0206] Fig. 2 shows a schematic representation of the principle of an increasing gas barrier with platelet materials;

[0207] Fig. 3A-C each show a schematic cross-section of a reinforced thermoplastic pipe (RTP) according to the present invention;

[0208] Fig. 4 shows a method of manufacturing of a fibre-reinforced thermoplastic unidirectional (UD) barrier tape according to the present invention;

[0209] Fig. 5A-B each show a method of manufacturing of a reinforced thermoplastic pipe (RTP) according to the present invention.

[0210] DETAILED DESCRIPTION OF THE DRAWINGS

[0211] Fig. 1 shows a schematic cross-section of part of an RTP 3. The RTP 3 comprises, from a centre 5 to a periphery 7 of the RTP 3, a thermoplastic inner liner 9, a reinforcing layer 1 1 , and a thermoplastic outer jacket 15. The reinforcing layer 1 1 comprises a layer of UD barrier tape 1 and a layer of UD tape 13. A barrier coating 17, present on a first side of the UD barrier tape 1 , comprises platelets 19 and forms a barrier. The barrier prevents that hazardous fluids, diffusing from the centre 5 of the RTP 3 through the thermoplastic inner liner 9 towards to the reinforcing layer 11 , can reach the reinforcing fibres, dispersed in the thermoplastic matrix material of the UD tape 13 and UD barrier tape 1. As illustrated the barrier coating 17 is oriented in planar alignment tangent to a surface of the UD barrier tape 1. The barrier coating can comprise platelets. Platelets can be disposed in a printed ink. The principle of increasing the gas barrier by applying the barrier coating 17 is shown in Fig. 2. On the left side of Fig. 2, no platelets 19 are present and fluids are diffuse relatively fast through the barrier. On the right side of Fig. 2, the barrier coating 17 comprises platelets 19. The platelets 19 are platelike structures that are oriented in a layer of polymer matrix material in such a manner that they form layers of platelets 19 stacked upon each other. This increases the tortuosity for the gas molecules form an increasing gas barrier such that fluids diffuse relatively slow through the barrier coating 17. Obviously, planar orientation with respect to the UD tape and a dense packing of platelets gives the highest barrier.

[0212] Fig. 3A-C each show a cross-sectional view of an RTP 3 according to the present invention. Each of the shown RTPs 3 comprises, from the centre 5 to the periphery 7, a thermoplastic inner liner 9, a reinforcing layer 11 , and a thermoplastic outer jacket 15. The reinforcing layers 11 are build up differently in each schematically depicted situation.

[0213] In Fig. 3A, the reinforcing layer 11 comprises, from the centre 5 to the periphery 7, a layer of the UD barrier tape 1 and a layer of the UD tape 13. The barrier coating 17 is applied on the first side of the UD barrier tape 1 and is facing towards the centre 5 of the RTP 3 and forms a barrier between the thermoplastic inner liner 5 and the reinforcing layer 1 1 .

[0214] In Fig. 3B, the reinforcing layer 11 comprises, from the centre 5 to the periphery 7, a layer of the UD tape 13 and a layer of the UD barrier tape 1 . The barrier coating 17 is applied on the second side of the UD barrier tape 1 and is facing towards the periphery 7 of the RTP 3 and forms a barrier between the thermoplastic outer jacket 15 and the reinforcing layer 1 1 .

[0215] In Fig. 3C, the reinforcing layer 11 comprises, from the centre 5 to the periphery 7, a first layer of the UD barrier tape 1 , a layer of the UD tape 13, and a second layer of the barrier UD tape 1. The barrier coating 17 is applied on the first side of the first layer of the UD barrier tape 1 and is facing towards the centre 5 of the RTP 3 and DRD007 ^ / vO-ORD forms a barrier between the thermoplastic inner liner 5 and the reinforcing layer 11. The other barrier coating 17 is applied on the second side of the second layer of the UD barrier tape 1 and forms another barrier between the thermoplastic outer jacket 15 and the reinforcing layer 11 .

[0216] The method 101 of manufacturing of the UD barrier tape according to the present invention is schematically shown in Fig. 4. The method comprises the steps of: 1) providing 103 the UD tape 13; 1 b) surface treating 107 with a corona discharge the UD tape 13 on the first side and / or the second side to provide a surface-treated UD tape 13; 2) applying 105 the ink, or platelet suspension, on the first side and / or the second side of the surface-treated UD tape 13 by inkjet printing a roll-to-roll process to provide the UD barrier tape 1 on which the barrier coating 17 is present on the first side and / or the second side of the UD tape 13; and 4) heat curing 109 the barrier coating 17 applied in step 2) to thermally bond the barrier coating 17 to the UD tape 13, to provide a consolidated UD barrier tape 1.

[0217] Fig. 5A shows the method 201 of manufacturing an RTP 3 according to the fourth aspect of the present invention, comprising the steps of: 1) providing 203 the thermoplastic inner liner 9; 2) one or more steps of winding 205 on the thermoplastic inner liner 9 the two or more layers of the UD tape 13, of which at least one layer is of the UD barrier tape 1 according to the first aspect of the present invention, wherein during the winding step 205 two layers of UD tape 13 is / are applied, thereby forming the reinforcing layer 11 on the thermoplastic inner liner 9; optionally the UD (barrier) tapes 1 ,13 wound on the inner liner 9 are converted to a fully bonded reinforcement by heating (209i) the tape under tension and pressure to about 10°C above the melting point of the matrix polymer (or if a polymer blend is used for the matrix, the highest melting polymer in the blend) followed by cooling (209ii) to bond the reinforcing layer 11 and the thermoplastic inner liner 9; and 3) applying 207 the thermoplastic outer jacket 15 on the reinforcing layer 11 to provide the RTP 3 having the barrier coating 17.

[0218] Fig. 5B shows a similar method 201 as shown in Fig. 5A. The method 201 differs in that the winding 205 has two steps of winding 205i,205ii. In each winding step 205i,205ii, one or more layers of the UD tape 13 are applied on the thermoplastic inner liner 9. This method 201 also provides the RTP 3 having the barrier coating 17.

[0219] EXAMPLES

[0220] The present invention is further elucidated based on the example below which is illustrative only and not considered limiting to the present invention. Those skilled in the art will readily recognize a variety of noncritical parameters that can be changed or modified to yield essentially the same results.

[0221] A UD tape with a PP matrix and glass fibre reinforcement was made by melt impregnation of fibres with a melt extrusion process. The weight fraction of fibres was 60 wt.%. One side of the tape was resin rich, with a PP layer of about 50 microns in thickness. The GF-PP tape was cut into a sheet 10 cm x 10 cm. The resin rich side was treated with ultrasonic. The treated side of the 10 cm x 10 cm UD tape was then coated with a graphene paste by screen printing, and heat cured at 140 °C to fix the ink and to obtain a UD barrier tape. The thickness of the coating after curing was about 10 pm.

[0222] The permeation of H2O, CO2, H2S and CH4of uncoated and graphene coated GF-PP tape was measured. The UD barrier tape showed a water permeation and CO2permeation rate that was significantly lower than that of an uncoated GF-UD tape.

[0223] 10 layers of the UD barrier tape, wherein the barrier coating was present on the first side of the UD tape and the thickness of each layer of UD barrier tape was 300 pm, were stacked and laminated by compression moulding (180 °C, pressure of 20 MPa, 5 minutes; cooling under pressure to room temperature). This gave a ‘banded’ laminate with graphene layers spaced apart by about 300 pm.

[0224] The UD tape with a PP matrix and glass fibre reinforcement of Example 1 was used. In this method, the UD GF-PP tape was coated with graphite oxide. Graphite oxide was produced by the method of Hummers, W. S. & Offeman, R. E. Preparation of graphitic oxide. J. Am. Chem. Soc. 80, 1339-1339 (1958). The Graphite oxide flakes were then suspended in water. The aqueous suspension was used to coat the GF-PP UD tape (after treatment with corona discharge) using a rod-coating (Meyer bar) method.

[0225] Next, the graphite oxide coating on the plastic film was chemically reduced to graphene by immersing it in a reducing agent such as an aqueous hydrogen iodide or ascorbic acid (Vitamin C) aqueous solution, as described in Y. Su V.G. Kravets, S.L. Wong, J. Waters, A.K. Geim & R.R. Nair, ‘Impermeable barrier films and protective coatings based on reduced graphene oxide’ (NATURE COMMUNICATIONS | 5:4843 | DOI: 10.1038 / ncomms5843 | www.nature.com / naturecommunications).

[0226] A 30 nm graphene coating on a UD GF-PP tape made by chemical reduction of graphite oxide led to a significant reduction of water permeation compared to the uncoated GF-UD tape.

[0227] 10 layers of the UD barrier tape, wherein the barrier coating was present on the first side of the UD tape and the thickness of each layer of UD barrier tape was 300 pm, were stacked and laminated by compression moulding (180 °C, pressure of 2 Mpa, 5 minutes; cooling under pressure to room temperature). This gave a ‘banded’ laminate with graphene layers spaced apart by about 300 pm.

[0228] The same was done with the uncoated GF-PP tape to provide a laminate of layers of uncoated GF-PP tape.

[0229] The laminate with the coating showed a water permeation and CO2permeation rate that was significantly lower than that of the laminate having the layers of uncoated GF- UD tape.

[0230] Example 3 The method of chemical vapour deposition (VCD) of graphene onto a copper belt and transfer of the deposited graphene to the UD tape was done according to procedures known to those well versed in the art of CVD. This was described in the description.

[0231] A 30 nm graphene coating on UD GF-PP tape prepared by chemical reduction of graphite oxide and permeation tests of the resulting UD barrier tape showed a significant reduction of water permeation compared to uncoated GF-UD tape.

[0232] The procedure described by F. Ding et al., ‘Biomimetic nanocoatings with exceptional mechanical, barrier, and flame-retardant properties from large-scale one-step coassembly’, Science Advances 2017; 3:e1701212 was used to deposit clay platelets on a GF-PP UD tape. The surface of the UD tape was treated with corona discharge. Polyvinyl alcohol was added to exfoliated clay platelets in an aqueous suspension with glutaraldehyde and HCI catalyst to crosslink the clay platelets and the polyvinyl alcohol. This suspension was used to coat the surface-treated GF-PP UD tape. After coating the tape, the clay platelets were oriented in a planar orientation with a densified arrangement. The loading of the platelets in the coating was high (i.e., 50 wt.% or higher).

[0233] The water permeability and CO2permeability of the clay-coated GF-PP UD tape were significantly lower compared to uncoated GF-PP UD tape. The PP naturally has a low permeation of water but a high permeability for O2and CO2. The clay coating reduces the water permeability by a modest amount but it greatly reduces CO2transmission.

[0234] 10 layers of the UD barrier tape, wherein the barrier coating was present on the first side of the UD tape and the thickness of each layer of UD barrier tape was 300 pm, were stacked and laminated by compression moulding (180 °C, pressure of 20 Mpa, 10 minutes; cooling under pressure to room temperature) to prepare a laminate of 3 mm thickness. The clay coating remains in interval bands of about 300 microns.

[0235] Modifications and additions to the methods and examples disclosed above are obvious to those skilled in the art and covered by the scope of the appended claims. Embodiments and examples of the first aspect of the present invention are also applicable to the second or further aspects of the present invention.

[0236] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope thereof. The scope of the present invention is defined by the appended claims. One or more of the objects of the invention are achieved by the appended claims.

Claims

CLAIMS1. A fibre-reinforced thermoplastic unidirectional (UD) barrier tape (1) arranged for use in a reinforced transportation pipe (RTP) (3) configured for transporting fluids, said RTP comprising from a centre (5) to a periphery (7): a thermoplastic inner liner (9); a reinforcing layer (11), comprising two or more layers of a fibre-reinforced thermoplastic unidirectional (UD) tape (13), wherein at least one of said two or more layers of the UD tape (13) is said UD barrier tape (1); and a thermoplastic outer jacket (15), wherein said UD barrier tape (1) has a first side facing towards the centre (5) of the RTP (3) and a second side facing towards the periphery (7) of the RTP (3), wherein said UD barrier tape (1) comprises: a thermoplastic matrix material; and unidirectionally aligned reinforcing fibres dispersed within said thermoplastic matrix material, wherein said unidirectionally aligned reinforcing fibres extend in a longitudinal direction of the UD barrier tape (1), and characterized in that the UD barrier tape (1) further comprises: a barrier coating (17) comprising platelets (19) disposed in a printed ink and oriented in planar alignment tangent to a surface of the UD barrier tape (1), wherein said barrier coating (17) is present on at least a part of the first side of the UD barrier tape (1) for forming a barrier between the two or more layers of the UD tape (13) and the thermoplastic inner liner (9) of the RTP (3); and / or wherein said barrier coating (17) is present on at least a part of the second side of the UD barrier tape (1) for forming a barrier between the two or more layers of the UD tape (13) and the thermoplastic outer jacket (15) of the RTP (3).

2. The UD barrier tape (1) according to claim 1 , wherein the platelets in the barrier coating (17) are selected from the group consisting of graphene, graphene oxide, graphite, clay - such as montmorillonite, bentonite, nontronite, beidellite,wolkonskoite, hectorite, saponite, sepiolite, stevensite, sauconite, sobokite, swinfordite, silicic acid, phyllosic acid zirconium phosphates, dichalcogenides, polyhedral oligomeric silsesquioxane, potassium titanate, kanemite, macatite, octosilicate, magadiite, kenyaite, mica, vermiculite, illite, ledikite, tubular attapulgite, brucite, gibbsite, berlinite, vantasselite, talc, serpentine, chrysotile-asbestos, revdinskite, palygorskite, muscovite, phlogopite, biotite, glauconite, pennite, clinochlor, kaolinite, chrysocollonite-garnierite, chrysocollonite-garnierite, chrysocollonite-garnierite - aluminium flakes, aluminium nitride, boron nitride, carbon nanotubes and nanoparticles, barium sulphate nanoparticles, silica nanoparticles, and one or more combinations thereof, preferably graphene and clay.

3. The UD barrier tape (1) according to claim 1 or 2, wherein the barrier coating (17) comprises platelets in an amount of between 20 and 90 wt.%, preferably between 50 and 90 wt.%, more preferably between 70 and 90 wt.%, based on the total weight of the barrier coating.

4. The UD barrier tape (1) according to any of the preceding claims, wherein the platelets have an interlayer distance of between 5 and 200 nm and / or wherein the platelets have a length of between 0.5 and 200 pm and width of between 1 and 200 pm and / or wherein the platelets have a thickness of between 0.35 and 100 nm.

5. The UD barrier tape (1) according to any of the preceding claims, wherein the barrier coating (17) covers at least 70%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, most preferably at least 99%, of the first side and / or the second side of the UD barrier tape (1).

6. The UD barrier tape (1) according to any of the preceding claims, wherein the barrier coating (17) is present on both the first side and the second side of the UD barrier tape (1).

7. The UD barrier tape (1) according to any of the preceding claims, wherein the barrier coating (17) has a thickness of between 0.01 and 50 pm, preferably between 0.1 and 25 pm, more preferably between 1 and 10 pm, and / or wherein the ratiobetween a thickness of the UD barrier tape (1) to a thickness of the barrier coating (17) (tuD : tBM) is between 3,000:1 and 6:1 , preferably between 300:1 and 12:1 , more preferably between 150: 1 and 30:1.

8. A method (101) of manufacturing a fibre-reinforced thermoplastic unidirectional (UD) barrier tape (1) according to any of the preceding claims, said method (101) comprising: inkjet printing in a roll-to-roll process the ink, the ink comprising the platelets and a monomer that can be subsequently polymerized by heating said monomer below a melting point of the thermoplastic matrix material, on a first side and / or a second side of a UD tape (13) to provide the UD barrier tape (1) on which the barrier coating (17) is present on at least a part of the first side and / or the second side of the UD tape (13).

9. The method (101) of manufacturing the UD barrier tape (1) according to claim8, wherein the method (101) comprises inkjet printing in a roll-to-roll process and wherein the method (101) comprises the steps of:1) providing (103) the UD tape (13); and2) applying (105) the ink on the first side and / or the second side of the UD tape (13) by inkjet printing in a roll-to-roll process to provide the UD barrier tape (1) on which the barrier coating (17) is present on the first side and / or the second side of the UD tape (13).

10. The method (101) of manufacturing the UD barrier tape (1) according to claim9, further comprising the step of:1 b) prior to step 2), surface treating (107) with a corona discharge, plasma, or ultrasonic the UD tape (13) provided in step 1) on the first side and / or the second side to provide a surface-treated UD tape.11 . The method (101) of manufacturing the UD barrier tape (1) according to claim 9 or 10, further comprising the step of:3) heat curing or ultraviolet curing (109) the barrier coating (17) applied in step 2) to bond the barrier coating (17) to the UD tape (13), or surface-treated UD tape, to provide a consolidated UD barrier tape.

12. A use of a fibre-reinforced thermoplastic unidirectional (UD) barrier tape (1) according to any of the claims 1-7 or manufactured according to the method (101) according to any of the claims 8-11 for a reinforced thermoplastic pipe (RTP) (3) configured for transporting of fluids, preferably hydrocarbon fluids, said RTP (3) comprising from a centre (5) to a periphery (7) a thermoplastic inner liner (9); a reinforcing layer (11), comprising two or more layers of a fibre-reinforced thermoplastic unidirectional (UD) tape (13) and wherein at least one of said two or more layers of the UD tape (13) is said UD barrier tape (1); and a thermoplastic outer jacket (15).

13. A reinforced thermoplastic pipe (RTP) (3) configured fortransporting fluids, said RTP comprising from a centre (5) to a periphery (7): a thermoplastic inner liner (9); a reinforcing layer (11), comprising two or more layers of a fibre-reinforced thermoplastic unidirectional (UD) tape (13) and wherein at least one of said two or layers of UD tape (13) is a UD barrier tape (1) according to any of the claims 1-7 or manufactured according to the method (101) according to any of the claims 8-11 ; and a thermoplastic outer jacket (15).

14. A reinforced thermoplastic pipe (RTP) (3) configured fortransporting fluids, said RTP (3) comprising from a centre (5) to a periphery (7): a thermoplastic inner liner (9); a reinforcing layer (11), comprising two or more layers of a fibre-reinforced thermoplastic unidirectional (UD) tape (13) and wherein at least one of said two or more layers of the UD tape (13) is a fibre-reinforced thermoplastic unidirectional (UD) barrier tape (1) having a first side facing towards the centre (5) of the RTP (3) and a second side facing towards the periphery (7) of the RTP (3), wherein said UD barrier tape (1) comprises a thermoplastic matrix material and unidirectionally aligned reinforcing fibres dispersed within said thermoplastic matrix material, wherein said unidirectionally aligned reinforcing fibres extend in a longitudinal direction of the UDbarrier tape (1), and wherein said UD barrier tape (1) further comprises a barrier coating (17) comprising platelets (19) disposed in a printed ink and oriented in planar alignment tangent to a surface of the UD barrier tape (1), wherein said barrier coating (17) is present on at least a part of the first side of the UD barrier tape (1) for forming a barrier between the two or more layers of the UD tape (13) and the thermoplastic inner liner of the RTP (3) and / or wherein said barrier coating (17) is present on at least a part of the second side of the UD barrier tape (1) for forming a barrier between the two or more layers of the UD tape (13) and the thermoplastic outer jacket (15) of the RTP (3); and a thermoplastic outer jacket (15).

15. A method (201) of manufacturing a reinforced thermoplastic pipe (RTP) (3) according to claim 13 or 14, the method (201) comprising the steps of:1) providing (203) the thermoplastic inner liner (9);2) one or more steps of winding (205) on the thermoplastic inner liner (9) the two or more layers of the UD (barrier) tape (1 ,13), wherein during each winding step, one or more layers of UD (barrier) tape (1 ,13) is / are applied, thereby forming the reinforcing layer (11) on the thermoplastic inner liner (9);2a) optionally, heating (209i) the reinforcing layer (11) at a temperature about 10 °C above the melting temperature of the thermoplastic matrix material and cooling (209ii) to bond the reinforcing layer (1 1) and the thermoplastic inner liner (9); and3) applying (207) the thermoplastic outer jacket (15) on the reinforcing layer (1 1) to provide the RTP (3) having the barrier coating (17).

Images