Liner for rehabilitating drinking water lines

Abstract

The invention relates to a tubular liner for rehabilitating drinking water lines, to a rehabilitated drinking water line, to a method for rehabilitating drinking water lines, and to the use of the liner for rehabilitating drinking water lines.

Description

[0001] SAERTEX multiCom GmbH Düsseldorf, August 13, 2025

[0002] Our reference number: SD 46847 / RC

[0003] SAERTEX multiCom GmbH

[0004] Brochterbecker Damm 52, 48369 Saerbeck, Germany

[0005] Liners for the rehabilitation of drinking water pipes

[0006] Description

[0007] The invention relates to a tubular liner for the rehabilitation of drinking water pipes, a rehabilitated drinking water pipe, a method for rehabilitating drinking water pipes and the use of the liner for the rehabilitation of drinking water pipes.

[0008] Until now, it has not been possible to rehabilitate drinking water pipes without excavation. While technologies for constructing longer drinking water pipes already existed, these pipes previously had to be excavated for rehabilitation. Unlike wastewater or drinking water, drinking water places very specific demands on the pipe's leak tightness, as the resin in the resin-impregnated fiber tubes of liners often does not fully cure, allowing components of the resin, such as monomers, to leach into the drinking water. Therefore, the standard liners used for rehabilitating wastewater or drinking water pipes are unsuitable for rehabilitating drinking water pipes.

[0009] While it is known that so-called styrene barriers are used in liners to prevent reactive diluents like styrene from migrating out of the resin, these existing styrene barriers primarily serve to prevent styrene from coming into contact with, for example, very hot UV light sources during installation and potentially igniting. A certain degree of diffusion is therefore not a problem with these state-of-the-art styrene barriers. Consequently, these state-of-the-art styrene barriers typically exhibit a monomer migration rate through the barrier layer of significantly more than 10 pg / (dm³). 2 -d) where dm stands for decimeter and d for day. These are therefore generally unsuitable for applications in the field of drinking water pipe rehabilitation.

[0010] EP2573442A1 describes an internally coated liner intended for the rehabilitation of wastewater or freshwater pipes and unsuitable for the rehabilitation of drinking water pipes, as this type of liner often has seams through which resin monomers could potentially diffuse and contaminate the drinking water. Furthermore, the styrene barriers used in these liners are generally unsuitable for drinking water applications (so).

[0011] EP3626444A1 concerns the rehabilitation of high-temperature pipelines. In the liner described therein, it is particularly preferred if the inner coating described therein does not have a styrene barrier.

[0012] US2022143948A1 describes methods and materials for an intelligent composite renewal system for stand-alone, storage and renewed pipelines, including for reducing carbon emissions and converting existing pipelines to transport hydrogen and other clean fuels.

[0013] EP3279542A1 describes a method for installing a cover element on the inner wall of a circular pipe or vertical shaft.

[0014] US6170531B1 describes flexible tubular lining material.

[0015] CA1339253C describes a lining material for pipelines.

[0016] US6374862B1 describes a pipeline for lining pipes and methods for manufacturing them.

[0017] In contrast to liners for gas pipelines, the aim of the present invention is to prevent migration or diffusion of molecules from the outside to the inside (e.g. monomers such as styrene into the drinking water) and not from the inside to the outside (e.g. hydrogen to the outside).

[0018] The object of the present invention is therefore to provide a technology with which drinking water pipes can be renovated without trenching.

[0019] In a first embodiment, this problem is solved by a tubular liner for the rehabilitation of drinking water pipes comprising a. at least one resin-impregnated fiber layer, and b. at least one barrier layer, wherein the barrier layer is suitable for reducing the diffusion of components of the resin through the barrier layer into the drinking water, and wherein the barrier layer comprises at least one material selected from polymer, metal, oxide, nitride, carbide and / or mixtures or combinations thereof. Polymer, metal, oxide, nitride, or carbide within the meaning of the invention also includes mixtures of different polymers, metals, oxides, nitrides, or carbides.

[0020] The liner or resin-impregnated fiber layer can be uncured or cured. Preferably, the liner or resin-impregnated fiber layer is cured.

[0021] The liner according to the invention is preferably invertible. Previously known fiber tubes, such as those described in EP1180225B1, are not invertible because the resin-impregnated fiber tube layer in these products is usually only loosely folded and therefore falls apart during inversion. The liner according to the invention thus has the advantage that the more cost-effective inversion process can be carried out with this liner. However, the liner according to the invention can also be a pull-in liner. Liner structure

[0022] In its cured state, the wall thickness of the liner (i.e., all layers of the cured liner combined) is in the range of 3 to 25 mm. The inner diameter of the cured liner is preferably in the range of 10 to 400 cm, more preferably 20 to 120 cm. The ratio of inner diameter to wall thickness of the cured liner is preferably in the range of 8 to 400.

[0023] The liner according to the invention may or may not have an inner coating as described in EP2573442A1.

[0024] In connection with the aforementioned inversion method, it should be noted that the liner's structure before installation differs between the inversion and insertion methods. The layer sequence for a liner used in the insertion method is the same as the layer sequence after installation in the pipe. The layer sequence before installation for an inversion liner is, of course, the reverse of the layer sequence after installation. Since both variants are the same liner, they are covered by this invention.

[0025] Preferably, the barrier layer has no longitudinal seam. A longitudinal seam would be very difficult to seal in such a way that monomer could no longer penetrate the seam and contaminate the drinking water. The barrier layer is therefore preferably seamless.

[0026] The individual layers can comprise one or more layers or material webs. These layers or material webs are, for example, bonded together across their entire surface.

[0027] The liner according to the invention can have further layers.

[0028] An anchoring layer is preferably arranged between the barrier layer and the fiber layer. Preferably, at least the barrier layer and the anchoring layer are bonded together either by material bonding or force bonding. Because at least these layers are preferably bonded together either by material bonding or force bonding, they cannot move relative to each other, unlike in the prior art. This significantly improves the stability of the entire layer structure. Furthermore, the preferably inner barrier layer is considerably reinforced by the associated anchoring layer, so that the preferably inner barrier layer is no longer easily damaged.

[0029] The anchoring layer, which preferably consists of a thermoplastic material, preferably has a thickness in the range of 10 to 5000 pm, particularly 30 to 500 pm. The anchoring layer advantageously consists of a nonwoven fabric, a hot melt adhesive, or a combination of these. Most preferably, the nonwoven fabric consists of glass, thermoplastic materials, PAN, or mixtures thereof. The thermoplastic materials are, for example, selected from polyethylene, polypropylene, or polyester. The hot melt adhesive is, for example, polyamide, polyethylene, AP AO (amorphous polyolefin), EVAC (ethylene vinyl acetate copolymer), TPE-E (polyester elastomer), TPE-U (polyurethane elastomer), TPE-A (copolyamide elastomer), or vinylpyrrolidone / vinyl acetate copolymer, as well as mixtures thereof.

[0030] The liner according to the invention can have an outer layer. This is preferably arranged on the side of the liner that faces the inner wall of the rehabilitated drinking water pipe.

[0031] The outer layer preferably has a thickness in the range of 40 to 2000 pm, and most preferably a thickness in the range of 200 to 800 pm. The outer layer is advantageously not permeable to UV radiation so that the resin in the resin-impregnated fiber tube layer does not harden, for example, during storage or transport. The outer layer can consist, for example, of a polymer or of a nonwoven fabric with a polymer laminated to it. Suitable materials for the polymer and / or nonwoven fabric include, for example, polyvinyl chloride, polyethylene, and / or polypropylene. The outer layer can, for example, be a (tubular) film made of polyvinyl chloride with a thickness in the range of 200 to 800 pm. Furthermore, the outer layer can have a nonwoven fabric made of polyethylene and / or polypropylene on the inside of the polyvinyl chloride film.A barrier layer, described in more detail below, can be arranged between the polyvinyl chloride film and the polyethylene and / or polypropylene nonwoven fabric.

[0032] The outer layer can also be fiber-reinforced, and in particular reinforced with a woven fabric. A separate outer barrier layer can preferably be arranged between the outer layer and the fiber layer, acting, for example, as a barrier against monomers or reactive diluents. This can be, for example, a styrene barrier. In principle, this outer barrier layer can have the same preferred features as the barrier layer, independently of the barrier layer itself. For example, the outer barrier layer can also be laminated with a polymer fleece.

[0033] Between the barrier layer and the anchoring layer, a layer of thermoplastic polymer such as polypropylene or polyethylene can be provided. This layer can, for example, be extruded. Preferably, the molecular weight of the material in this layer is lower than that of the material in the adjacent barrier layer to ensure a high degree of flowability and thus a strong bond.

[0034] Material bonding or force bonding within the meaning of the invention can advantageously mean that the respective layers are either fully or partially laminated, bonded, or bonded to one another. If the layers are partially bonded, preferably at least 40% of the surface area of ​​the layers is bonded or, alternatively, bonded at specific points. In contrast to the prior art, this completely prevents the layers from slipping relative to one another. The layers can additionally or alternatively be bonded by extruding a highly flowable thermoplastic material between the layers during manufacturing.

[0035] The barrier layer is preferably located on the side of the two outer surfaces of the liner that is inside the renovated drinking water pipe.

[0036] Liners, such as pipe liners, are intentionally manufactured with an undersize to prevent wrinkling. The undersize depends on the nominal diameter and varies, for example, between 1 and 4% of the diameter. To be particularly suitable for applications such as the rehabilitation of drinking water pipes, it is preferable that the permeability and / or migration rate of monomer through the barrier layer does not increase with a 10% elongation of the diameter.

[0037] The liner is preferably pressure-resistant and can be operated at pressures ranging from 0.1 to 50 bar, particularly preferably from 2 to 35 bar. This is preferably the maximum operating pressure. Liners typically require a relatively high wall thickness to withstand such pressures continuously. However, due to particularly preferred embodiments of the layer structure, the liner according to the invention can be operated at very high pressures with a significantly reduced wall thickness of the cured liner. The wall thickness of the cured liner is therefore preferably in the range of 5 to 15 mm. The ratio of the inner diameter (in mm) of the cured liner to the wall thickness (in mm) of the cured liner is preferably in the range of 30 to 100, and most preferably in the range of 35 to 90.The product (multiplication) of the inner diameter of the cured liner (in mm) and the maximum operating pressure (in bar) is preferably in the range of 6000 to 9000 mm-bar, and most preferably in the range of 6500 to 8500 mm-bar. The maximum operating pressure can be determined in a long-term burst test (10,000 h) according to DIN EN 1796 / DIN EN 14364 and DIN EN 1447 for Class A liners according to DIN EN ISO 11295 and for Class IV liners according to AWWA M28. Structure of the resin-impregnated fiber layer.

[0038] The resin-impregnated fiber layer can have a thickness ranging from 2 to 30 mm. The fiber layer is preferably a non-woven fabric, a braid, a woven fabric, a mat, a knitted fabric, a nonwoven fabric, a felt, a knitted fabric, or a combination or multilayer structure of these textile fabrics. The fiber material of the resin-impregnated fiber layer is preferably selected from flax, basalt, glass, carbon, aramid, gel-spun polyethylene (for example, Dyneema®), PAN, thermoplastic polymer, or mixtures thereof. Thermoplastic fibers can be, for example, made of polypropylene, polyethylene, or polyester. The resin material can be selected from the group consisting of unsaturated polyester resins, silicate resins, vinyl ester resins, epoxy resins, or mixtures thereof.

[0039] The diameter of the fibers preferably lies in the median range of 10 to 300 pm.

[0040] In the resin-impregnated fiber layer, the resin is preferably not or only partially polymerized. The resin composition advantageously contains 0.1 to 20 parts by weight of a thickening agent, and in particular an isocyanate, per 100 parts by weight of resin. It has been found that this results in a sufficiently thickened resin composition for pipe rehabilitation applications, while remaining liquid enough during production to completely impregnate the anchoring layer and the fiber layer.

[0041] The uncured resin preferably contains an initiator for curing by light and / or heat. If the barrier layer also contains metal, the resin of the resin-impregnated fiber layer preferably contains an initiator for thermal curing. The uncured resin preferably contains, as a reactive diluent, a monomer selected from the group consisting of styrene, acrylate, and / or mixtures thereof. Styrene or acrylate, as used in the invention, also includes mixtures of different styrenes or acrylates.

[0042] The residual monomer content (especially the residual styrene content) in the cured resin-impregnated fiber layer is preferably in the range of 0 to 5 wt.%, particularly preferably 0.3 to 4 wt.%, based on the weight of the liner. The residual monomer content can be determined according to DIN 53394-2 (DWA-A 143-3).

[0043] Structure of the barrier layer

[0044] The barrier layer is suitable for reducing the diffusion of drinking water through the barrier layer, wherein the barrier layer comprises at least one material selected from polymer, metal, oxide, nitride, carbide and / or mixtures thereof.

[0045] The barrier layer is, for example, seamless. The barrier layer is preferably tubular. The barrier layer is particularly preferably a film tube. A nonwoven fabric can preferably be laminated onto one or both sides of the film tube and / or the barrier layer. The nonwoven fabric is preferably made of a thermoplastic material (such as polyester, polypropylene, or polyethylene). The thickness of the nonwoven fabric can range from 10 to 500 µm. This has the advantage that the barrier layer can then bond particularly well with adjacent layers, such as the fiber layer, during the curing of the liner.

[0046] The polymer may preferably be selected from the group consisting of polyamide, high-density polyethylene (HOPE), low-density polyethylene (LDPE), liquid crystal polyester resin, bismaleimide resins (e.g.graphite fiber-reinforced bismaleimide resin (such as Virgin IM7 / 977-2 / AF-191), ethylene vinyl alcohol resin (EVOH, such as Kuraray's EVAL Resin), fluoroelastomer (such as VITON A), polytetrafluoroethylene (PTFE), nitrile butadiene resin (such as BUNA N), ethylene propylene diene monomer rubber (EPDM, such as EPDM filled with silica and / or carbon particles), acrylonitrile styrene acrylate copolymer (ASA), polychlorotrifluoroethylene (CTFE), Noryl, Parylene, polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), polyphenylene sulfide (PPS), polystyrene (PS), polysulfone (PSU), polyvinyl chloride (PVC), polyvinyl fluoride (PVF), Santoprene UPVC (Unplasticized Polyvinyl Chloride), silicone and / or mixtures thereof.

[0047] The metal is preferably selected from steel, copper, aluminum, and iron. The aluminum may preferably be oxidized and / or anodized. The metal may, for example, be applied as a layer onto another layer or layer by thermal spraying, metal plating, or physical vapor deposition (PVD). If the barrier layer contains metal, the metal is preferably present as one of several layers within the barrier layer. This metal layer may preferably have a thickness in the range of 2 to 100 pm, particularly preferably in the range of 5 to 50 pm. The barrier layer may, for example, comprise a metallic foil tube. This metal layer may alternatively preferably have a thickness in the range of 100 to 300 pm, particularly preferably in the range of 100 to 200 pm.

[0048] The metal layer can be applied, for example, by vapor deposition, CVD, or PVD. In this case, the metal layer preferably has a thickness in the range of 0.01 to 0.06 pm. Alternatively, a foil tube containing a layer of metal (such as aluminum or copper) can be used, in which case the metal layer has a thickness in the range of 5 to 20 pm. For example, the liner can first be installed and cured without this foil tube, and then a foil tube containing a layer of metal can be inserted. The oxide can preferably be selected from aluminum oxide, magnesium oxide, indium tin oxide (ITO), chromium oxide, erbium oxide, silicon oxide, and / or mixtures thereof. The oxide can, for example, be indium tin oxide, as it is transparent in a wavelength range of 400 to 700 nm and is therefore also suitable for light-curing resin systems.If the barrier layer contains oxide, the oxide is preferably present as one of several layers within the barrier layer. This oxide layer can preferably have a thickness in the range of 10 to 200 nm.

[0049] The nitride may preferably be selected from boron nitride, titanium nitride, silicon nitride and / or mixtures thereof. If the barrier layer contains nitride, the nitride is preferably present as one of several layers within the barrier layer. This nitride layer may preferably have a thickness in the range of 10 to 200 nm.

[0050] The carbide can preferably be selected from silicon carbide, titanium carbide, and / or mixtures thereof. If the barrier layer contains carbide, the carbide is preferably present as one of several layers within the barrier layer. This carbide layer can preferably have a thickness in the range of 10 to 200 nm.

[0051] The barrier layer can, for example, comprise a layer of polymer from the aforementioned preferred polymers and a layer of metal (for example, as a film or applied to the polymer layer). These layers can be directly adjacent to one another. For instance, the barrier layer can comprise a laminate of a metal film and a polymer film from the aforementioned preferred metals and polymers. Alternatively, the barrier layer can comprise a composite film of at least one metal film and at least one polymer film.

[0052] If the barrier layer contains metal, the metal can be present as a layer, foil, or sheet within the barrier layer. This layer, sheet, or foil can, for example, have a thickness in the range of 10 to 90 pm. For instance, the barrier layer can consist of a layer, foil, or sheet of copper with a thickness in the range of 10 to 90 pm. The barrier layer can preferably consist of a layer of metal foil or be entirely made of the metal foil.

[0053] If the barrier layer contains polymer, then the polymer can be present as a layer, film, or sheet within the barrier layer. This layer, sheet, or film can, for example, have a thickness in the range of 100 to 1000 pm.

[0054] Preferably, the polymer is a thermoplastic polymer and, in particular, not an elastomer. Preferably, the polymer is semi-crystalline. The degree of crystallinity of the polymer is preferably in the range of 50 to 95%. The degree of crystallinity K of the polymer can be calculated from the ratio of the enthalpy of fusion measured by DSC to the literature value for 100% crystalline material.

[0055] One or more barrier layers can be arranged within the liner. If multiple barrier layers are arranged within the liner, they can have the same or different structures, for example, they can be made of the same or different materials and / or have the same or different thicknesses.

[0056] The barrier layer advantageously has a thickness in the range of 10 to 1500 pm. In particular, the barrier layer has a thickness in the range of 200 to 1000 pm. This allows the barrier layer to be protected from mechanical damage, for example by the liner curing equipment, while still being thin enough to allow sufficient heat or UV radiation to pass through for curing. This barrier layer advantageously has several layers. One of these layers is, for example, a barrier layer. This barrier layer is intended to prevent the diffusion of reactive diluents, such as styrene, from uncured resin. This barrier layer is advantageously one of the layers of the barrier layer that is not on the outside ("outside" here means "visible to the observer" and / or "adjacent to the anchoring layer"). The barrier layer contains, for example, 10 wt.% to 40 wt.% of...The barrier layer consists of a material selected from the group comprising polyamide, ethylene-vinyl alcohol copolymer, PBT, PET, halogenated polymers, or mixtures thereof. Furthermore, the barrier layer preferably contains thermoplastic polymers such as polyethylene or polypropylene. The barrier layer can, for example, be a film consisting of several layers. For instance, a polyamide layer can be enclosed by two thermoplastic polymer layers within the barrier layer. This polyamide layer can, for example, have a thickness in the range of 5 to 200 pm. The barrier layer advantageously has a thickness in the range of 10 to 500 pm.

[0057] With the new barrier layer according to the invention, which is preferably bonded to the liner by material or force, it is possible for the first time to rehabilitate drinking water pipes in an environmentally friendly way using a liner-based rehabilitation method. Furthermore, it is possible for the first time to use UV-curable resins and radical generators.

[0058] The barrier layer advantageously comprises at least one and preferably two outer layers ("outer" here meaning "visible to the observer" and / or "adjacent to the anchoring layer") made of polyurethane, polyethylene, and / or polypropylene. This outer layer advantageously has a thickness in the range of 50 to 1000 µm. For example, the outer layer adjacent to the anchoring layer (e.g., as an adhesive layer) can be thinner than the other outer layer facing the center of the tube (e.g., a wear layer). This allows the barrier layer to provide even better protection against mechanical stresses. This at least one outer layer made of polyurethane, polyethylene, and / or polypropylene preferably has a coating of metal, oxide, nitride, carbide, and / or mixtures thereof on the side facing the rest of the liner structure.This coating can be applied, for example, by vapor deposition, PVD, CVD, or ALD. This coating preferably has a thickness in the range of 20 to 200 nm.

[0059] In a completely different technical field – namely the encapsulation of organic LEDs – there is a need for highly transparent gas diffusion barriers (see, for example, Jeong, EG, Kwon, JH, Kang, KS, Jeong, SY, & Choi, KC (2019). A review of highly reliable flexible encapsulation technologies towards rollable and foldable OLEDs. Journal of Information Display, 21 f, pages 19-32; Peter van de Weijer, Piet CP Bouten, Sandeep Unnikrishnan, Hylke B. Akkerman, Jasper J. Michels, Ton MB van Mol, High-performance thin-film encapsulation for organic light-emitting diodes, Organic Electronics, Volume 44, 2017, pages 94-98). The inventors of the present invention have now discovered that this technology can also be used in liners and prevents not only the diffusion of gases, but also the diffusion of monomers such as styrene.

[0060] For example, it is preferred if the barrier layer is composed of several layers. It is particularly preferred if an inorganic layer is combined with an organic layer, the inorganic layer being thinner than the organic layer. The inorganic layer preferably contains predominantly an oxide (for example, MgO and / or Al₂O₃). The organic layer preferably contains a polymer. The polymer can be a pure polymer (such as an acrylate-based polymer in the Fraunhofer Institute's BARIX coating) or a hybrid polymer (such as a silane-based inorganic / organic hybrid polymer). The organic layer preferably has a thickness in the range of 0.1 to 50 pm, and most preferably a thickness in the range of 1 to 20 pm. The inorganic layer can preferably have a thickness in the range of 20 to 500 nm, and most preferably in the range of 30 to 200 nm.

[0061] The inorganic layer is preferably produced using Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD), as these techniques have fewer pinholes or other defects in the coatings.

[0062] It is preferred that at least one of the layers is a silane-based inorganic / organic hybrid polymer layer (silamer layer) adjacent to an AhCL layer. The AhCL layer preferably has a thickness in the range of 30 to 200 nm. This layer can, for example, be deposited using ALD (Atomic Layer Deposition). The silamer layer preferably has a thickness in the range of 1 to 10 pm (see also Kwon JH et al. Design of Highly Water Resistant, Impermeable, and Flexible Thin-Film Encapsulation Based on Inorganic / Organic Hybrid Layers / / ACS applied materials & interfaces. 2018. Vol. 11. No. 3. pp. 3251-3261.).

[0063] It may also be preferred that the barrier layer comprises several adjacent inorganic oxide layers. It is particularly preferred that one of the inorganic layers comprises predominantly Al₂O₃ and an adjacent layer comprises predominantly an oxide selected from the group consisting of SiO₂, ZrO₂, ZnO, HfO₂, and / or TiO₂. These adjacent layers may, independently of each other or both preferably, have a thickness in the range of 10 to 200 nm.

[0064] Alternatively, it may also be preferred that the barrier layer comprises an organic layer with two inorganic layers adjacent to this layer on both sides. The organic layer preferably contains predominantly a polymer. This polymer can, for example, be an organic coating for planarization (OCP), as described in the aforementioned OLED applications. The thickness of the organic layer can preferably be in the range of 10 to 50 pm. The inorganic layers can, for example, contain predominantly oxides and / or nitrides, most preferably SiN. The inorganic layers can preferably have a thickness in the range of 50 to 200 nm. The inorganic layers can, for example, be obtained by ALD.

[0065] To ensure the safety of the liner according to the invention for drinking water, the liner, and in particular the barrier layer, must demonstrate in migration tests that no harmful substances pass through the barrier layer into the drinking water.

[0066] In accordance with standard EN 12873-1 :2014, the test results are expressed as migration rates (M) of monomer in pg / (dm³). 2.d) where d stands for days and dm for decimeters. These results are to be converted into estimated values ​​of the monomer concentrations at the tap (Ctap), defined as Ctap = M * CF, where CF is the corresponding conversion factor to d / dm. CF preferably depends on the outer diameter of the liner. If the outer diameter of the liner is less than 300 mm, CF is preferably 10 d / dm. If the outer diameter of the liner is greater than or equal to 300 mm, CF is preferably 5 d / dm. Preferably, however, CF is 10 d / dm. The literature also often uses a value MTCtap, which indicates the maximum tolerable concentration at the tap in pm / l.

[0067] Preferably, the Ctap value for monomer (especially styrene) from the resin or resin composition is less than 1 pg / l, particularly preferably less than 0.5 pg / l, and most preferably less than 0.1 pg / l. The Ctap value is measured one day after liner installation, five days after liner installation, and 31 days after liner installation at a water temperature of 20 °C. Preferably, the Ctab value on the 31st day after liner installation is lower than the Ctab value five days after liner installation. Ctap is determined in accordance with standard EN 12873-1:2014 and the German Federal Environment Agency's assessment criteria for plastics and other organic materials in contact with drinking water (KTW-BWGL; March 7, 2022).

[0068] The migration rate of monomer (especially styrene) through the barrier layer is preferably in the range of 0.001 to 0.1 pg / (dm³). 2.d), particularly preferably in a range of 0.001 to 0.01 pg / (dm³) 2 .d), where dm stands for decimeter and d for day. The migration rate is determined according to standard EN 12873-1:2014 and the assessment basis for plastics and other organic materials in contact with drinking water (KTW-BWGL; March 7, 2022) of the German Federal Environment Agency.

[0069] If the barrier layer is a foil tube or incorporates a foil tube, the elongation at break of the foil in this foil tube is in the range of 40 to 1000%. This can be measured, for example, according to DIN EN ISO 527 / ASTM D 882.

[0070] The barrier layer is preferably at least partially fiber-reinforced, particularly preferably carbon fiber-reinforced (for example, CFRP) and / or glass fiber-reinforced. The fibers are preferably not impregnated with resin. In the present invention, the barrier layer is intended to prevent monomers from a potentially incompletely cured resin-impregnated fiber layer from leaching into the drinking water. It would therefore be counterproductive to initially use uncured resin (i.e., monomers) in the barrier layer, as these could then leach into the drinking water if the resin of the barrier layer does not fully cure. Therefore, it is preferred that the fibers in the barrier layer are not resin-impregnated. The fibers preferably have a median diameter in the range of 10 to 100 pm, most preferably in the range of 15 to 80 pm.The material of the fibers of the barrier layer is preferably selected from flax, basalt, glass, carbon, aramid, gel-spun polyethylene (for example Dyneema ®), PAN, thermoplastic polymer or mixtures thereof.

[0071] Renovated

[0072] In a further embodiment, the problem underlying the invention is solved by a renovated drinking water pipe comprising a hardened liner according to the invention.

[0073] Methods for the rehabilitation of drinking water pipes

[0074] In a further embodiment, the problem underlying the invention is solved by a method for rehabilitating drinking water pipes, in which a liner according to the invention is inserted into a drinking water pipe or produced in the drinking water pipe and then cured. Curing is preferably carried out using UV light or thermally. The production of the liner in the drinking water pipe preferably involves first inserting a liner without or without a complete barrier layer into the drinking water pipe and then applying a material to the inside of the inserted liner. The material can be selected from metal, oxide, nitride, and / or carbide. The material can preferably be metal, oxide, nitride, and / or carbide as described in more detail above (for example, the material combinations or thicknesses described above, etc.). The application of the material preferably takes place after the remaining liner has cured.The material can be applied by inserting and securing a tubular film or by coating it. The tubular film can preferably be specified with all the features that are meaningful to a person skilled in the art, as described above for the barrier layer. The coating can be applied by vapor deposition, CVD, or ALD.

[0075] Preferably, the curing process is thermal. In the process according to the invention, thermal curing has the advantage that, for example, epoxy-based resins can be used to impregnate the fiber layer, or metal (foils) can be used as a diffusion barrier. Preferably, at least one peroxide, one azo initiator, or mixtures thereof are used as the initiator for the thermal curing process. According to the invention, the curing time is chosen to be at least 20%, and particularly preferably at least 80%, longer than would be calculated using conventional formulas. of the liner

[0076] In a further embodiment, the problem underlying the invention is solved by using the liner according to the invention for the rehabilitation of a drinking water pipeline.

[0077]

[0078] For the production of the impregnated fiber tube (liner) according to the invention, a 1 m wide and 20 m long web of a 2 mm thick, conventionally used glass fiber fabric was wound around a tube consisting of a 100 µm thick layer of conventionally used polypropylene nonwoven fabric, onto which a 300 µm film was laminated. This film consisted of three layers of HDPE (each 100 µm thick), one layer of aluminum (50 µm thick), and another layer of HDPE (100 µm thick). The web was subsequently permanently bonded to the tube during curing. This was made possible primarily by the fact that the polypropylene nonwoven fabric faced the glass fiber fabric, and the resin, when the liner was impregnated, impregnated both the glass fiber fabric and the polypropylene nonwoven fabric. The two longitudinal edges of the glass fiber fabrics were then joined by sewing. This process was repeated to produce a 20 m long liner with two layers of glass fiber fabric without overlapping longitudinal seams.The re-wrapping was therefore carried out in such a way that the longitudinal seams did not lie on top of each other, but were arranged on different sides of the liner. The liner was then impregnated with a commercially available heat-initiated styrene-containing UP resin for vacuum relining, as is usual for liners, and tightly wrapped with a 100 µm thick HDPE film, as is standard for liners. The resin contained the usual additives, such as wetting and deaerating agents. The exact composition of the resin was as follows: 1100 parts by weight of crude resin (unsaturated polyester resin, Crystic U 1307 Ti V02 from Scott Bader), 2.64 parts by weight of deaerator (BYK-A 555 from BYK-Chemie GmbH), 3.19 parts by weight of defoamer (BYK-A515 from BYK-Chemie GmbH), 265 parts by weight of filler (Apyral 15 from Nabaltec AG), 16.5 parts by weight of styrene (from BÜFA Chemikalien GmbH & Co.KG), 6.6 parts by weight of peroxide initiator (Peroxan BCC from Pergan Hilfsstoffe für industrielle Prozesse GmbH), 7.7 parts by weight of another peroxide initiator (Peroxan HXP from Pergan Hilfsstoffe für industrielle Prozesse GmbH), 8.25 parts by weight of another peroxide initiator (Peroxan PO from Pergan Hilfsstoffe für industrielle Prozesse GmbH). After being inserted into a pipe requiring rehabilitation (here with an inner diameter of 325 mm), the liner was cured using heat, as is usually the case – however, with twice the usual heat exposure time (3 hours instead of 1.5 hours). A hot water heating module, referred to as a hotbox, was used for this purpose. For heat curing, the liner was first filled with unheated water and vented. The water was then pumped into the hotbox via a return / suction hose and heated there to a temperature of 45°C.A water circulation pump was used to create a water circuit. Heating the water took approximately one hour. After another three hours (instead of the usual 1.5 hours), the curing process was complete. The water was then cooled in a controlled manner. Finally, the water was drained from the liner, and the closed end was opened using a milling robot or a saw. A final inspection of the installation was performed with a push camera.

[0079] The inner diameter of the old pipe was approximately 318 mm. The wall thickness of the cured liner was approximately 4 mm.

[0080] Due to the significantly longer curing time, the residual styrene content in the cured liner was very low, at less than 1.5 wt.% based on the weight of the liner, and was determined according to DIN 53394-2 (DWA-A 143-3).

[0081] The Ctap value for styrene through the barrier layer was determined according to standard EN 12873-1:2014 and the assessment basis for plastics and other organic materials in contact with drinking water (KTW-BWGL; March 7, 2022) of the German Federal Environment Agency. This value was less than 0.1 pg / l. The Ctap value was measured one day after liner installation, five days after liner installation, and 31 days after liner installation at a water temperature of 20 °C. The Ctab value on the 31st day after liner installation was lower than the Ctab value five days after liner installation.

[0082] The migration rate of styrene through the barrier layer was determined in accordance with standard EN 12873-1:2014 and the assessment basis for plastics and other organic materials in contact with drinking water (KTW-BWGL; 7 March 2022) of the German Federal Environment Agency.

[0083] This was less than 0.01 gg / (dm³). 2.d), where dm stands for decimeter and d for day.

Claims

Patent claims 1. Tubular liner suitable for the rehabilitation of drinking water pipes, comprising a. at least one resin-impregnated fiber layer, wherein the resin in the uncured state comprises at least one monomer, and b. at least one barrier layer, wherein the barrier layer is suitable for reducing the diffusion of components of the resin through the barrier layer into the drinking water, and wherein the barrier layer comprises at least one material selected from polymer, metal, oxide, nitride, carbide and / or mixtures or combinations thereof.

2. Liner according to claim 1, characterized in that it is cured and the The resin of the resin-impregnated fiber layer has hardened.

3. Liner according to one of claims 1 to 2, characterized in that the The barrier layer is fiber-reinforced, but the fibers are not resin-impregnated.

4. Liner according to one of claims 2 or 3, characterized in that the The residual styrene content of the liner is in the range of 0.3 to 4 wt.% based on the weight of the liner.

5. Liner according to one of the preceding claims, characterized in that the The barrier layer is seamless.

6. Liner according to one of the preceding claims, characterized in that the The barrier layer has a layer of metal foil or consists of metal foil.

7. Liner according to one of the preceding claims, characterized in that The barrier layer comprises a composite film made of at least one metal film and at least one polymer film.

8. Liner according to one of the preceding claims, characterized in that the barrier layer contains at least one inorganic layer with at least one an organic layer is combined, wherein the inorganic layer has a smaller thickness than the organic layer, wherein the inorganic layer predominantly contains an oxide, wherein the organic layer contains a polymer, wherein the organic layer has a thickness in the range of 0.1 to 50 pm, and wherein the inorganic layer has a thickness in the range of 20 to 500 nm.

9. Liner according to any one of claims 2 to 8, characterized in that the Migration rate of monomer through the barrier layer in the range of 0.001 to 0.1 pg / (dm³) 2 .d), particularly preferably in a range of 0.001 to 0.01 pg / (dm³) 2 .d), where dm stands for decimeter and d for day and the migration rate is determined according to standard EN 12873-1 :2014.

10. Liner according to any one of claims 2 to 8, characterized in that the The ratio of the inner diameter of the cured liner in mm to the wall thickness of the cured liner in mm is in a range of 30 to 100.

11. Rehabilitated drinking water pipe comprising a cured liner according to one of the Claims 2 to 10.

12. Method for rehabilitating drinking water pipes, characterized in that a liner according to one of claims 1 or 3 to 10 is inserted into a drinking water pipe or produced in the drinking water pipe and then cured.

13. Use of the liner according to any one of claims 1 to 10 for the rehabilitation of a Drinking water line.

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