AT17135U2 - Thermally insulated carrier pipes with cell gas containing HFO - Google Patents

Abstract

The invention relates to a thermally insulated conduit pipe (1) for use in flexible pipe systems, comprising at least one medium pipe (4), at least one thermal insulation (3) arranged around the medium pipe and at least one outer jacket (2) arranged around the thermal insulation, said Medium pipe (4) is designed as a flexible pipe section, said outer jacket (2) optionally comprises a barrier (9) made of plastic, and said thermal insulation (3) comprises a foam, the cell gas of which is 10-100 vol% hydrofluoroolefins (HFOs) and 0-50 vol % (Cyclo) alkanes and 0-50 vol% CO2, and wherein said HFO is selected from the group comprising the compounds R1233zd, and / or R1336mzz and wherein said alkane is selected from the group comprising propane, butanes, (cyclo) -Pentanes, (cyclo) -hexanes and said thermal insulation (3) being a foam selected from the group of polyurethanes (PU), polyisocyanurates (PIR), thermoplastic polyesters (PET ) and thermoplastic polyolefins.

Description

description

THERMALLY INSULATED MEDIUM PIPES WITH HFO CONTAINING CELL GAS

The invention relates to pipe systems containing thermal insulation, in particular thermally insulated medium pipes and thermally insulated covering devices or sleeves for connecting pipes with improved thermal insulation.

Pipe systems containing thermal insulation, also called pre-insulated pipe systems, or thermally insulated pipe systems, are known and proven. Such pipe systems include flexible or rigid medium pipes which are surrounded by thermal insulation, which in turn is surrounded by a jacket, and possibly sleeves and / or covering devices. Depending on the structure, these pre-insulated pipe systems are called plastic medium pipe systems (PMR) or plastic jacket pipe systems (KMR). In the former, the medium pipes used have a certain flexibility, so that the entire assembly can be wound on drums with a certain amount of force. This is why one speaks of flexible pipe systems. With the latter, the medium pipes used cannot be bent, which is why the entire network is also referred to as rigid pipe systems. Correspondingly, thermally insulated medium pipes or conduit pipes with one or more thermal insulation layers are known; likewise their production. Processes for the continuous production of thermally insulated carrier pipes are known from EP0897788 and EP2213440. From EP2248648 a method for producing individual, rigid pipe sections is known.

In such pipe systems, the composition of the cell gases changes over time in the foam (e.g. polyurethane, PU) that is usually used as an insulating material. This takes place by diffusion of nitrogen and oxygen from the environment into the foam and by diffusion of the foaming or cell gases originally contained in the foam, in particular carbon dioxide and other blowing agents, out of the foam. The air gases have a significantly higher thermal conductivity than the carbon dioxide originally contained and the propellants usually used.

In order to minimize these diffusion processes, it has been proposed to integrate so-called barrier layers into the outer jacket.

Metallic layers can be used as barrier layers. When using metallic layers, not only is gas exchange completely prevented, which is desirable, but water vapor is also completely prevented from diffusing. This is particularly problematic when using carrier pipes made of plastic, since water typically flows through them as a medium, which is why a constant, albeit small amount, of water vapor migrates through their walls. This water vapor must be able to penetrate to the outside or to come into equilibrium with the environment, as otherwise water will accumulate in the thermal insulation of the thermally insulated pipe over time, which significantly increases the thermal conductivity and there is a risk that the thermal insulation is permanently damaged.

[0006] Layers which consist of one or more polymeric materials can be used as barrier layers. For example, EP1355103 describes thermally insulated line pipes which contain a barrier layer made of ethylene vinyl alcohol (EVOH), polyamide (PA) or polyvinylidene dichloride (PVDC). Furthermore, EP2340929 describes a plastic jacket pipe whose outer jacket is designed as a multilayer pipe and has a gas permeation barrier layer (“barrier”) in its interior. The pipes described in these documents are difficult to manufacture and / or have insufficient insulation properties. Line pipes with thermal insulation and a polymeric barrier layer are known from CH710709 (subsequently published) and WO2004 / 003423; these polymers contain polyketones or EVOH.

To connect thermally insulated pipes, molded parts and connecting pieces are

cke used. In particular, cover shells are used as molded parts, as described in WO2008 / 019791. Or sleeves are used as connecting pieces, especially when connecting rigid pipes. The problems mentioned also arise with such molded parts and connecting pieces.

It is an object of the invention to provide a thermally insulated conduit pipe as well as molded parts and connecting pieces which do not have the disadvantages mentioned.

The objects outlined above are achieved according to the independent claims. The dependent claims represent advantageous embodiments. Further advantageous embodiments can be found in the description and the figures. The general, preferred and particularly preferred embodiments, ranges, etc. given in connection with the present invention can be combined with one another as desired. Individual definitions, embodiments, etc. can also be omitted or not relevant.

The present invention is described in detail below. It goes without saying that the various embodiments, preferences and ranges disclosed and described below can be combined with one another as desired. In addition, depending on the embodiment, individual definitions, preferences and ranges cannot be used. Furthermore, the term “comprising” includes the meanings “containing” and “consisting of”.

The terms used in the present invention are used in the generally customary sense familiar to the person skilled in the art. Unless the direct relationship results in a different meaning, the following terms have in particular the meaning / definitions given here.

The present invention is further illustrated by the figures; In addition to the description below, further embodiments of the invention can be found in these figures.

Fig. 1 shows schematically the structure of a pipe (1) according to the invention in cross section. Here (2) the outside (6) of the outer jacket faces the environment and the inside (5) faces the thermal insulation; (3) indexed the thermal insulation with cell gas; (4) the carrier pipe.

Fig. 2 shows schematically the structure of a preferred embodiment of the outer jacket (2). (7) is the outer polymer layer (especially thermoplastic); (8) an outer adhesion promoter layer; (9) the barrier layer; (10) an inner adhesion promoter layer and (11) the inner polymer layer (especially thermoplastic).

Fig. 3 shows a graphical representation of the dependence of the value of the thermal conductivity (abscissa in the unit mW / m * K) of a PU foam measured at 50 ° C as a function of the composition of the cell gas (ordinate in the unit vol% ). The squares represent cyclopentane, the circles CO », the triangles HFO.

4 shows a graphic representation of the average pore size (abscissa in the unit µm) of a PU foam as a function of the cell gas composition (ordinate in the unit% by volume). The squares represent cyclopentane, the circles CO », the triangles HFO.

Fig. 5 shows a graphic representation of the viscosity (abscissa in the unit mP * sec) of a polyol with different contents (ordinate in the unit wt%) of cyclopentane or HFO 1233zd. The squares represent cyclopentane, the triangles HFO.

In a first aspect, the invention thus relates to a pipe system containing thermal insulation (also called pre-insulated pipe system or thermally insulated pipe system), in which said thermal insulation comprises a foam whose cell gas is hydrofluoric

contains lefins (HFOs). Such pipe systems, but without said cell gas, are known per se and include thermally insulated conduit pipes, sleeves and cover devices for connecting such conduit pipes.

In a first embodiment, the invention relates to a thermally insulated conduit pipe (1), comprising at least one medium pipe (4), at least one thermal insulation (3) arranged around the medium pipe and at least one outer jacket (2) arranged around the thermal insulation, characterized in that said outer jacket (2) optionally comprises a barrier (9) made of plastic, and that said thermal insulation (3) comprises a foam, the cell gas of which contains the components defined below.

In a second embodiment, the invention relates to a cover device made of plastic, in particular for the connection points of at least two pipe pieces, which are connected there, the cover device having at least one thermal insulation (3) and at least one outer jacket (2) arranged around the thermal insulation , characterized in that said outer jacket (2) optionally comprises a plastic barrier, and that said thermal insulation (3) comprises a foam, the cell gas of which contains the components defined below.

In a further embodiment, the invention relates to a sleeve made of plastic for the connection of thermally insulated pipes, the sleeve having at least one thermal insulation (3) and at least one outer jacket (2) arranged around the thermal insulation, characterized in that said outer jacket (2 ) optionally comprises a barrier made of plastic, and that said thermal insulation (3) comprises a foam, the cell gas of which contains the components defined below.

This aspect of the invention will be explained in more detail below

Thermal insulation (3): The thermal insulation encloses the medium pipe partially or completely, preferably completely. Foamed plastics ("foams"), which contain a cell gas in their cells, are particularly suitable as thermal insulation. The thermal insulation can be homogeneous along its cross section or made up of several layers. Typically, the thermal insulation in line pipes is built up homogeneously.

Cell gases: The gases present in the thermal insulation are referred to as cell gases. These are a result of production and are made up of chemical and physical blowing agents or their reaction products. Typically, such cell gases are added during the foaming process, or they are formed during the foaming process.

According to the present invention, the cell gas in the foam of the thermal insulation is characterized in that it contains hydrofluoroolefins (HFOs). The cell gas can only consist of one or more HFOs and possibly also contain other components. The cell gas advantageously contains 10-100 vol% HFOs, preferably 20-100 vol% HFOs, more preferably 30-100 vol% HFOs, particularly preferably 40-100 vol% HFOs, very particularly preferably 50-100 vol% HFOs. Correspondingly, the cell gas can contain further components.

In one embodiment, the cell gas contains 0-50 vol% (cyclo) alkanes, preferably 0-45 vol% (cyclo) alkanes, more preferably 0-40 vol% (cyclo) alkanes, particularly preferably 0-35 vol% ( Cyclo) alkanes. The ratio of HFOs to (cyclo) alkanes is preferably at least 2.5: 1, preferably at least 3: 1.

In a further embodiment, the cell gas additionally or alternatively contains up to 50 vol% CO », preferably 0-40 vol% CO», particularly preferably 0-30% CO ».

In a further embodiment, the cell gas additionally or alternatively contains up to 5 vol% nitrogen (N2) and / or oxygen (O>).

These further components can be added to the propellant, such as, for example, the (cyclo) alkanes mentioned; they can arise during the production of the foam, such as CO »; they can get into the foam during the production process, such as air, O>, N2.

It has been shown, surprisingly, that even with proportions as low as, for example, 10 vol% HFO in the cell gas, the properties of pipe systems, in particular of thermally insulated line pipes, improve in a number of features.

In particular, it was found that the line pipes described here have a surprisingly better insulation behavior. Without feeling bound by any theory, it is assumed that the improved insulation properties are not only due to the material properties of the HFOs (thermal conductivity), but also to improved foaming, caused by the changed viscosity.

In the case of PU foams and PIR foams, the addition of HFO to one of the two starting components (isocyanate or polyol) or during direct mixing in the mixing head leads to a marked decrease in viscosity. Without feeling bound by any theory, it is assumed that the reduced viscosity improves the mixing of the two components and thus promotes the formation of comparatively smaller cells.

In order to achieve a viscosity reduction in a similar order of magnitude with cyclopentane as the propellant, its content could alternatively also be increased by, for example, 1.86 times. This would be the factor by which the molecular weights of the HFO 1233zd (130.5 g / mol) and of cyclopentane (70.2 g / mol) differ, but this would have several disadvantageous consequences:

a) On the one hand, twice the amount of propellant gas would expand during the foaming process, which led to uncontrollable changes in the foam structure. Existing PU foams and the production facilities are optimized for the smaller amount of cyclopentane and large changes in the amount of the expanding blowing agent would result in extensive new developments.

b) Cyclopentane acts as a plasticizer for the PU foam. An amount increased by 1.86 times leads to its marked softening. On the one hand, this is not desired because the foam plays a key role, i. H. is indispensable for the mechanical stability of the entire network. On the other hand, this is not desired because the increasing softness of the foam in the manufacturing process means that the entire pipe assembly deviates more and more from the ideal round cross-sectional geometry. It has thus been found that the complete or partial replacement of cyclopentane by HFOs improves the mechanical properties of the foam. Usually, cyclopentane is added to the starting material in order to reduce its viscosity; however, the maximum amount is limited by the fact that the foam produced must have sufficient mechanical strength. By replacing cyclopentane with HFOs, these conflicting goals can be achieved. The use of a comparable amount of HFO leads to starting materials with lower viscosity with the same mechanical strength of the final foam. In this way, the producibility can be improved while the product quality remains the same.

It was also found that the addition of the HFO to one of the starting components or the direct addition to the two starting components in the mixing head reduces their flammability. This effect is very advantageous because it reduces the safety requirements for such a production system and thereby significantly simplifies the design of a corresponding production system and thus costs can be saved which would otherwise be incurred when working with combustible propellants.

In summary, it can thus be stated that the known problems can be solved in an elegant manner by the partial or complete replacement of cyclopentane (Cp) by HFOs. On the one hand, more propellant can be added, which leads to a desired reduction in viscosity. At the same time, however, the expanding effect remains essentially unchanged and no fundamental adjustments to the recipe or production system are required. Finally, by replacing the combustible cyclopentane with the non-combustible HFO, occupational safety is improved and the investment costs for such a production plant are reduced.

It was also found that high contents of (cyclo) alkanes, in particular cyclopentane, have a negative influence on the product quality. Experience has shown that too high a content of cyclopentane in the polyol leads to the formation of large bubbles in the foam, which are caused by the fact that the blowing agent (especially cyclopentane) is driven out of the foam by the temperature of the PU foam that is being formed.

In a continuous production process, the outer jacket is usually applied by extrusion and at this point in time, due to the high temperature of typically 80-250 ° C, is in a state in which it can be easily deformed. The bubbles are then visible on the outside of the insulated pipe because the escaping propellant inflates the outer jacket. This applies equally to insulated pipes with a corrugated, a smooth and a corrugated outer jacket. The escape of the blowing agent is promoted by the temperature of the extruded outer jacket. Pipes with such defects are to be regarded as rejects and can no longer be used for the intended purpose.

The formation of bubbles is prevented if the content of cyclopentane in the cell gas composition of the resulting insulating foam is 0-50% by volume, preferably 0-45% by volume, particularly preferably 0-40% by volume, most preferably 0-35% by volume.

Surprisingly, it was found that when using HFO as a blowing agent, the aforementioned bubble formation does not occur. This applies in particular when the content of the HFO in the cell gas composition of the resulting insulating foam is within the above-mentioned limits. The behavior described is all the more surprising since the boiling points in the case of the HFO 1233zd are 19 ° C and in the case of the HFO 1336mzz 33 ° C. This is in comparison to cyclopentane, which has a boiling point of 49 ° C. Because of these boiling points, the expectation is that the formation of bubbles would be more pronounced when using the low-boiling HFO as a blowing agent than when using higher-boiling (cyclo) alkanes, e.g. Cp. The opposite has been observed.

Hydroolefins (HFOs) are known and commercially available or can be produced by known methods. These are suitable as greenhouse gases, in particular because of their low global warming potential (GWP) and because of their harmlessness against the ozone layer in the atmosphere (Ozone Depleting Potential, ODP). The term includes both compounds that only contain carbon, hydrogen and fluorine, as well as those compounds that additionally contain chlorine (also referred to as HFCO) and each contain at least one unsaturated bond in the molecule. HFOs can be present as a mixture of different components or as a pure component. HFOs can also be present as isomeric mixtures, in particular E / Z isomers, or as isomerically pure compounds.

In the context of the present invention, particularly suitable HFOs are selected from the group comprising compounds of the formula (I)

RS aA CFz (I)

where R® is H, F, C1, CF3, preferably Cl, CFs, and R® is H, F, Cl, CF3, preferably H.

Particularly suitable HFOs are R1233zd (e.g. Solstice LBA, Honeywell) and R1336mzz (e.g. Formacel 1100, DuPont).

It has surprisingly been shown that the conduit pipes described here have an improved insulation behavior if the cell gases of the insulation contain at least 10 vol%, preferably at least 30 vol%, particularly preferably at least 50 vol% HFO. It has also been shown that the addition of such HFOs to the starting materials of the foam insulation leads to improved producibility.

(Cyclo) alkanes are known as cell gas for insulation in thermally insulated pipes. Said alkane or cycloalkane is advantageously selected from the group comprising propane, butanes, pentanes, cyclopentane, hexanes and cyclohexane. By combining (cyclo) alkane

HFO can be used to fine-tune the product properties and / or improve manufacturability and / or reduce costs with acceptable quality losses. The (cyclo) alkanes mentioned can be present as pure compounds or as mixtures; the aliphatic alkanes can be present as isomerically pure compounds or as isomer mixtures. A particularly suitable (cyclo) alkane is cyclopentane.

Carbon dioxide: If the foam is made of PU or polyisocyanurate (PIR), a certain amount of CO is typically produced, since the starting material polyol in technical quality normally contains a small amount of water. This then reacts with the isocyanate to form carbamic acid, which spontaneously CO »; splits off. The CO2 content of the cell gas is therefore linked to the purity of the starting materials and is typically below 50% by volume. If the starting materials are anhydrous, for example if polyolefins are foamed, the CO 2 content of the cell gas is 0 vol%. The CO »2 content of the cell gas can thus be influenced by the choice of starting materials (or their purity).

Other cell gases: Due to production, components can get into the cell gas from the atmosphere / ambient air. These are essentially N »and / or O> ;, for example air. The content of these cell gases is typically below 5% by volume. If the production plant is specially set up, contact with the atmosphere / ambient air can be avoided and the content of other cell gases is 0 vol%.

Foam: Said thermal insulation (3) comprises (i.e. contains or consists of) a foam. Such foams are known per se; foams which comply with the standards DIN EN 253: 2015-12 (especially for KMR) and EN156321: 2009 / A1: 2014, EN15632-2: 2010 / A1: 2014 and EN15632-3: 2010 / A1: 2014 (especially for PMPR). The term includes rigid foams and flexible foams. Foams can be closed-cell or open-cell, preferably closed-cell, in particular as set out in the standard DIN EN 253: 2015-12. Such foams are preferably selected from the group of polyurethanes (PU), polyisocyanurates (PIR), thermoplastic polyesters (especially PET), and thermoplastic polyolefins (especially PE and PP).

It has been shown that the following combinations of foam and cell gas are particularly advantageous:

- PU containing 50-100 vol% R1233zd and 0-50 vol% Cp;

- PU containing 50-100 vol% R1336mzz and 0-50 vol% Cp;

- PIR containing 50-100 vol% R1233zd and 0-50 vol% Cp;

- PIR containing 50-100 vol% R1336mzz and 0-50 vol% Cp;

- PET containing 50-100 vol% R1233zd and 0-50 vol% Cp;

- PET containing 50-100 vol% R1336mzz and 0-50 vol% Cp;

- PE containing 50-100 vol% R1233zd and 0-50 vol% Cp;

- PE containing 50-100 vol% R1336mzz and 0-50 vol% Cp.

In one embodiment, the cell gases mentioned add up to 100% by volume. In a further embodiment, these cell gases, together with CO 2 and air, add up to 100%. In a further embodiment, the ratio of HFO: Cp is at least 2.5: 1.

It has also been shown that the following combinations of foam and cell gas are particularly advantageous:

- PU containing 50-100 vol% R1233zd and 0-50 vol% Cp and 0-50 vol% CO »;

- PU containing 50-100 vol% R1336mzz and 0-50 vol% Cp and 0-50 vol% CO »;

- PIR containing 50-100 vol% R1233zd and 0-50 vol% Cp and 0-50 vol% CO »;

- PIR containing 50-100vol% R1336mzz and 0-50 vol% Cp and 0-50 vol% CO »

- PU containing 50-100 vol% R1233zd and 0-45vol% Cp and 10-40 vol% COs;

- PU containing 50-100 vol% R1336mzz and 0-45 vol% Cp and 10-40 vol% CO »;

- PIR containing 50-100vol% R1233zd and 0-45 vol% Cp and 10-40 vol% CO »

- PIR containing 50-100 vol% R1336mzz and 0-45 vol% Cp and 10-40 vol% CO ».

In one embodiment, the cell gases mentioned add up to 100% by volume. In a further embodiment, these cell gases, together with air, add up to 100%. In another ex

design is the ratio of HFO: Cp at least 3: 1.

In a further embodiment, the thermal insulation consists of the foams mentioned and the cell gases mentioned.

Barrier (9): Diffusion barriers are known per se in the field of line pipes / pipe systems. If there is a barrier, this barrier is designed as a layer. It is preferred that there is at least one barrier (9) as described below. It is particularly preferred that there is a barrier (9) as described below.

This layer (9) enables the diffusion of cell gases out of the thermal insulation and of gases outside the conduit (in particular air) into the thermal insulation to be reduced. This property is important to ensure the insulation capability of the conduit / pipe system over a longer period of time.

In an advantageous embodiment, this layer also enables the diffusion of water out of the thermal insulation. This property is particularly important for line pipes / pipe systems whose carrier pipe (4) is made of plastic. If an aqueous medium is transported in such pipe / pipe systems, water from the medium can get through the pipe into the insulation and thus reduce the insulation capacity and damage the insulation material.

In an advantageous embodiment, this layer also makes it possible to have a certain permeability for CO ». A particularly suitable value for the CO »permeability is in the range of 0.5 - 100 cmYm ** day * bar.

A barrier with selective properties is therefore advantageous, in particular: (i) permeable to water and water vapor, (ii) impermeable to the cell gases, which have a low thermal conductivity, (ill) permeable to the cell gases, which are produced due to production but have a relatively high intrinsic value Have thermal conductivity (for example CO »), (iv) impermeable to the gases from the environment, in particular nitrogen and oxygen and air.

It has been shown that a conduit of the type mentioned, in which the barrier comprises one or more of the polymers mentioned below, meets the requirements very well. According to the invention, the barrier can be present in a single layer or in several layers that are separate from one another. Furthermore, the barrier can be attached to the insulation or the outer jacket or in the outer jacket by means of an additional layer (“adhesion promoter layer” (8), (10)).

The barrier (9) can be arranged as a layer in the outer jacket (2); this is preferred; in particular, this configuration is preferred with two adhesion promoter layers (8, 10) adjoining the barrier (9), as shown in FIG. 2.

Furthermore, the barrier can be arranged as a layer on the outside and / or the inside of the outer jacket. Furthermore, the barrier can be formed by the outer jacket. Furthermore, the barrier (9) can be arranged as a layer between the thermal insulation (3) and the outer jacket (2). In this embodiment, the adhesion promoter layer is typically omitted. The barrier layer (9) advantageously has a layer thickness of 0.05-0.5 mm, preferably 0.1-0.3 mm. If the barrier forms the outer jacket, the barrier advantageously has a layer thickness of 0.5-5 mm. If present, the adhesion promoter layers (8, 10) advantageously have a layer thickness of 0.02-0.2 mm, independently of one another.

The barrier preferably comprises a copolymer of ethylene with carbon monoxide or with vinyl alcohol.

In an advantageous embodiment, the barrier comprises a polymer which contains polyketones or consists of polyketones. Correspondingly, the polymer layer comprises polyketones and blends of polyketones as well as laminates containing polyketones. Polyketones are known materials and are characterized by the keto group (C = O) in the polymer chain. In this embodiment, the polymer advantageously has 50-100% by weight, preferably 80-100% by weight, structural units of the formulas (II) or of the formula (III).

Oo

MH,

{II},

wherein

o is 1 or 2, preferably 1, is

p is 1 or 2, preferably 1,

q stands for 1-20 and

r stands for 1-20. Polyketones can be obtained by catalytically reacting carbon monoxide with the corresponding alkenes, such as propene and / or ethene. Such ketones are also known as aliphatic ketones. These polymers are commercially available, for example as polyketone copolymer (formula II) or polyketone terpolymer (formula III) from Hyosung. Such polyketones are also commercially available under the trade name Akrotek® PK. Suitable polymers have a melting temperature of over 200 ° C (measured with DSC 10 K / min according to 1SO11357-1 / 3) and / or have a low water absorption of less than 3%, measured according to DIN EN ISO 62 (saturation in water at 23 ° C).

In an advantageous embodiment, the barrier comprises a polymer which contains ethyl vinyl alcohol or consists of ethyl vinyl alcohol. In this embodiment, the polymer has 50-100% by weight, preferably 80-100% by weight,

Structural units of the formula (IV). OH

“M &

{IV}

wherein

m stands for 1-10,

n stands for 2-20. Suitable ethyl vinyl alcohols are, in particular, random copolymers in which the ratio m / n is 30/100 to 50/100. These polymers are commercially available, for example as the EVAL FP series or EP series from Kuraray. These are characterized by good processability; in particular, they can be processed very well together with the normally used sheath material polyethylene (PE) by coextrusion, because their melt viscosities and melting temperatures are in a similar range.

The combination of cell gases from the group of hydroolefins and barrier layers according to the formulas (II), (III), (IV) described here leads to particularly good, superadditive insulation properties of the thermally insulated conduits. Such a positive interaction of these components is surprising. Without feeling tied to a theory, this superadditive effect can be attributed to the barrier properties of the materials according to formulas (1), (II), (IV).

Medium pipe (4): In principle, all medium pipes suitable for thermally insulated pipes can be used. Accordingly, the medium pipe can be designed as a corrugated pipe, a smooth pipe or a pipe with a corrugated jacket; it can be a rigid and straight pipe section, a rigid bent pipe section or a flexible pipe section.

The medium pipe can consist of polymeric materials or metallic materials, preferably of polymeric materials. Such materials are known per se and are commercially available or produced by known methods. The materials are selected by a person skilled in the art according to the intended use, if necessary after routine tests.

In one embodiment, said medium pipe (4) is a flexible plastic pipe, the plastic

material selected from the group of acrylonitrile-butadiene-styrene (ABS), cross-linked polyethylene (PEXa, PEXb, PEXc), PE, polybutene (PB), polyethylene raised temperature (PE-RT), and polyketone (PK).

In a further embodiment, said medium pipe (4) is a flexible plastic pipe with an outer metal layer, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, PB, PE-RT and PK, the metal selected from the Group aluminum including its alloys. Such inner pipes are also known as composite pipes.

In a further embodiment, said medium pipe (4) is a rigid plastic pipe, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, PB, PE-RT and PK.

In a further embodiment, said medium pipe (4) is a flexible metal pipe, the metal selected from the group copper including its alloys, iron including its alloys (such as stainless steels), aluminum including its alloys.

In a further embodiment, said medium pipe (4) is a rigid metal pipe, the metal selected from the group copper including its alloys, iron including its alloys (such as stainless steels), aluminum including its alloys.

In a further embodiment of the medium pipe (4), the aforementioned plastic barrier can be arranged on the outside of the inner pipe or it can be formed by the medium pipe itself. A barrier on the carrier pipe, or formed by the carrier pipe itself, reduces the diffusion of steam from the carrier pipe into the thermal insulation. According to the invention, such a (“second”) barrier is combined with a further (“first”) barrier above the thermal insulation.

Outer jacket (2): In principle, all outer jackets suitable for thermally insulated pipes can be used. Correspondingly, the outer jacket can be designed as a corrugated pipe or a smooth pipe or as such with a corrugated jacket. It can be a rigid and straight pipe section, a rigid bent pipe section or a flexible pipe section.

The outer jacket can consist of polymeric materials or metallic materials, preferably of polymeric materials. Such materials are known per se and are commercially available or produced by known processes. The materials are selected by a person skilled in the art according to the intended use, if necessary after routine tests. Thermoplastic polymers such as commercial PE types are advantageously used. High density PE (HDPE), low density PE (LDPE), linear low density PE (LLDPE) are suitable. The layer thickness of the outer jacket (2) can vary within a wide range, but is typically 0.5-20 mm, including any barriers and barrier layers that may be present.

In one embodiment of the invention, the outer jacket contains the barrier described here, as described above. This configuration is advantageous since the jacket and barrier can be produced simultaneously and thus inexpensively by means of coextrusion.

In an alternative embodiment of the invention, the outer jacket does not contain the barrier described here, as described above. In this embodiment, the barrier is present as a separate layer. This configuration is advantageous because the jacket and barrier can be created separately and therefore flexibly.

In an advantageous embodiment, the invention relates to a conduit pipe as described here, in which said outer jacket (2) is designed as a corrugated pipe; and said medium pipe is designed as a flexible pipe section and in particular has at least one medium pipe based on polyethylene and thermal insulation based on PU and an outer jacket based on polyethylene.

In a further embodiment, the invention relates to a conduit as described here, in which said conduit is a rigid straight pipe section and in particular

at least one carrier pipe based on polyethylene or steel and thermal insulation based on PU and an outer jacket based on polyethylene.

In a further advantageous embodiment, the invention relates to a conduit pipe as described here, in which said outer jacket (2) is designed as a corrugated pipe. Such conduit pipes are advantageously combined with a medium pipe which is designed as a flexible pipe section and in particular comprises at least one medium pipe based on polyethylene or cross-linked polyethylene. Advantageously, such conduit pipes are also provided with thermal insulation (3) which comprises a foam, the cell gas of which has the above-mentioned composition (the cell gas particularly preferably containing at most 35% (cyclo) alkanes).

In a second aspect, the invention relates to a method for producing thermally insulated conduit pipes, sleeves and covering devices as described here. The invention is accordingly based on the object of creating improved methods for producing a conduit, sleeve or covering device which can be guided both continuously and discontinuously.

This aspect of the invention will be explained in more detail below.

In principle, the thermally insulated devices described here (cf. first aspect of the invention) can be produced in analogy to the known methods. The known blowing agents (e.g. cyclopentane, CO ») are partially or completely replaced by the HFOs described here. Correspondingly, systems known per se can be used for the production, if necessary after adaptation to new parameters, as can be carried out by a person skilled in the art in his routine work. The methods described in the documents EP0897788 and EP2213440 and EP2248648 and WO2008 / 019791 and EP1355103 and EP2340929 are hereby incorporated by reference.

In an advantageous embodiment of the method, the thermal insulation (3) is formed by foaming a plastic composition which contains polymer components for foam formation and HFO as a blowing agent. According to the invention, the HFO can either be metered into one of the components and then processed, or the starting components and the HFO are combined at the same time in a metering device (for example the mixing head).

In a further advantageous embodiment of the method, the plastic composition comprises two liquid components, the first component containing a polyol and HFO and the second component containing isocyanate. The isocyanate component is preferably one based on methylene diisocyanate. However, other isocyanates such as those based on toluene-2,4-diisocyanate or aliphatic isocyanates can also be used.

In a further advantageous embodiment of the method, the plastic composition comprises two liquid components, the first component containing a polyol and the second component containing isocyanate and HFO. In particular, those HFO components are preferred which have good miscibility with the two liquid components and whose boiling point is not too low (in particular not below 10 ° C.). This means that the outlay on equipment in production is low; Cooling systems only have to be provided to a small extent.

In a further advantageous embodiment of the method, the plastic composition consists of a molten component and this melt is combined with HFO under pressure.

Variant 1: If the thermally insulated pipe of this invention comprises one or more flexible medium pipe (s) and the outer jacket (13) is a plastic barrier, a variant of the method is advantageous in which

(A) the at least one medium pipe is fed continuously and with one to one

Hose-shaped plastic film is wrapped,

(b) a foamable plastic composition is introduced into the space between the medium pipe and the hose as a thermal insulation layer,

(c) the medium pipe and the hose are introduced into a tool formed from rotating molded parts and leave this tool at its end, and then

(d) the outer jacket is extruded onto the surface of the hose,

wherein the foamable plastic composition, the polymer component (s) for the foam

contains substance formation and HFO as a propellant. In this variant of the method

- The barrier between the foamed thermal insulation layer and the inside of the outer jacket are introduced by forming the hose from the polymer; or

- The barrier is applied by coextrusion together with the outer jacket; or

- the barrier can be applied directly to the hose; or

- First a layer of the outer jacket, followed by the barrier and followed by at least a second layer of the outer jacket.

In this variant of the method, the inner tube can also be used in step a

- are continuously withdrawn from a supply; or

- are produced continuously by extrusion.

Variant 2: If the thermally insulated pipe of this invention is one or more

includes rigid medium pipe (s) and the outer jacket (2) with a barrier made of plastic is a

driving variant advantageous in which

(a) a carrier pipe is centered within an outer jacket and

(b) a foamable plastic composition is introduced into the space between the carrier pipe and the outer pipe as a thermal insulation layer,

characterized in that the foamable plastic composition comprises the polymer

contains components for foam formation and HFO as a blowing agent. As mentioned earlier, can

said HFO are mixed with the two liquid components in a mixing head,

or said HFO is first mixed with one of the two components and then one

Mixing head fed. In this variant of the method

- the barrier between the foamed thermal insulation layer and the outside of the outer jacket are introduced in the form of a hose; or

- The barrier can be applied to the inside of the outer tube; or

- The barrier can be provided in the outer tube; or

- The barrier can be applied to the outside of the outer tube.

Variant 3: If the thermally insulated pipe of this invention contains thermal insulation made of a thermoplastic foam, for example made of PET, PE or PP, a process variant is advantageous in which the HFO is pressed directly into the molten polymer matrix and then through Expansion leads to foaming of the thermoplastic used. This can happen, for example, that a polymer mixture is melted in the extruder and HFO is fed into this melt under pressure. When leaving the tool, the blowing agent present causes foaming.

In a third aspect, the invention relates to new uses of HFOs. This aspect of the invention will be explained in more detail below.

In a first embodiment, the invention relates to the use of hydrofluoroolefins as cell gas for foam insulation in thermally insulated pipe systems, in particular in plastic medium pipe systems (PMR) and in plastic jacket pipe systems (KMR).

HFOs can advantageously be used as cell gas in foam insulation of line pipes, of covering devices and of sleeves, in particular of line pipes, of covering devices and of sleeves as described here (first aspect).

The invention is explained in more detail by means of the following examples; these are not intended to limit the invention in any way.

EXAMPLE 1: Manufacture of a conduit pipe according to the invention

Medium pipes with an outside diameter of 63 mm and a wall thickness of 5.8 mm consisting of PExa were continuously unwound from a storage drum. Shortly before the foaming station, this medium pipe was enclosed by a PE film, which in turn was unwound from a supply and fed via a forming shoulder. The corresponding amount of a mixture of a polymeric isocyanate based on diphenylmethylene diisocyanate (MDI) with an NCO content of 31% and a polyol with an OH number of 410 mg KOH / g ( determined according to ASTMD4274D) and with a water content of 0.8%). The isocyanate component was used slightly more than stoichiometrically relative to the reactive OH groups. The two components were intensively mixed in a high pressure mixing head at a pressure of 150 bar before the metered addition. The corresponding amount of HFO / cyclopentane was first stirred into the polyol component. Immediately after the addition of the two-component mixture, the tubular film was welded at the upper end. The PU foam produced immediately afterwards was forced into a cylindrical geometry by molding and after curing, a PE jacket was continuously extruded on.

The tubes obtained were analyzed with regard to the cell gases contained in the foam. For this purpose, small samples about 3 cm * in size were punched out of the foam and mechanically destroyed in a closed system so that the cell gases could get into the measuring apparatus. The gases present were determined qualitatively and quantitatively in a gas chromatograph.

In addition, the value of the thermal conductivity at 50 ° C. in accordance with the standards DIN EN 253: 2015-12 and EN ISO 8497: 1996 (Aso value) was measured on 3 m long pipe sections. Furthermore, the composition of the cell gas (according to the Chalmers method; described in Rämnas et al, J. Cellular Plastics, 31, 375-388, 1995) was determined; this method was also used in the following examples. The summary of the results can be found in the following table, a graphic representation can be seen in Figure 3:

Cell gas unit No1.1 No1.2 No1.3 No1.4 No1.5 CO2 * [Vol%] 100 51 34 31 32 Cp [Vol%] 0 46 14 9 0 HFO 1233zd [Vol%] 0 0 49 59 65 O2 + N »[Vol%] 0 3 3 1 3

Aso value [mW / m * K] 25.8 23.1 21.7 20.2 19.6

* CO »is inevitably formed as a by-product from the starting components and is not added (chemical blowing agent).

The data clearly demonstrate the positive influence of HFO on thermal conductivity.

EXAMPLE 2: Model experiment for foamable mixtures

An amount of 380-420 g of polyol was placed in a beaker and the amount of propellant given in the table was stirred in. The viscosity of the solution was determined in a Viscometer DV I-Prime rotary viscometer from Brookfield. The average value from three measurements was recorded.

The results are summarized in the table and shown graphically in FIG.

Content of added

Propellant Propellant Temperature Viscosity [mol / 100 g polyol] [K] [mPa * s] Pure polyol,

Polyol without blowing agent 292.8 2005 c 0.043 293.2 1245 P 0.071 293.1 946 0.041 293.0 1151 HFO 1233zd 0.071 293.1 815

The data clearly demonstrate the positive influence of HFO on viscosity.

EXAMPLE 3: Pore size in PU foams

According to DIN EN 253: 2015-12, the average pore size of PU foams, which contained different cell gases, was determined. An average of three measurements was formed in each case.

The results are summarized in the table and shown graphically in Figure 4:

Cell gas unit No3.1 No3.2 No3.3 CO2 [Vol%] 100 51 32 Cp [Vol%] 0 46 0 HFO 1233zd [Vol%] 0 0 65 O2 + N »[Vol%] 0 3 3 Pore size [um ] 151.0 138.1 130.6

The data clearly demonstrate the positive influence of HFO on cell size.

EXAMPLE 4: Determination of the flashpoints of the starting material

According to the Pensky-Martens method (DIN EN ISO 2719: 2003-9), the flash points of samples No 1 and No 3 were determined. Sample No. 2 was measured using the Abel-Pensky method (DIN 51755). The same polyol was used in each case as in Example 1. The results are summarized in the table.

Component Unit No4.1 No4.2 No4.3 Polyol [g / 100 g polyol] 100 100 100 Cp [9/100 g polyol] 0 4.8 0 HFO 1233zd [g / 100 g polyol] 0 0 8.9 Flash point

normalized to [° C] 102.8 56 1013 mbar

Sample No. 3 has a flash point which is significantly higher than comparative sample No. 2, which contains an equivamolar content of cyclopentane. In particular, sample No. 3 is not to be classified as flammable according to Regulation EC 440/2008.

EXAMPLE 5: Bubble formation as a function of the propellant

GENERAL: According to Example 1, thermally insulated line pipes with different cell gas compositions were produced.

EXAMPLE 5.1 (comparative experiment): An amount of cyclopentane (Cp) was metered into the polyol component with the aid of a static mixer, so that a content of 7% by weight was obtained based on the amount of polyol. On the surface of the pipe produced in this way, a

Length of 30 cm, twelve bubbles were counted, which had a diameter of more than 10 mm and were easily recognizable without any further aids.

EXAMPLE 5.2 An amount of 2% by weight of cyclopentane and 11% by weight of HFO 1233zd is metered into the polyol. No bubbles were found on the surface of the pipe produced in this way over a length of 400 m produced.

EXAMPLE 5.3: A quantity of 15% by weight of HFO 1233zd is metered into the polyol. No bubbles were found on the surface of the pipe produced in this way over a length of 350 m produced.

RESULTS OF EXAMPLES 5.1-5.3: The composition of the cell gases obtained in this way was determined by means of GC as in Example 1, and the tube obtained was checked visually.

Example: Composition control cell gas 5.1 69% Cp 12 bubbles over 0.3m length unusable (comparison) 29% CO »0% HFO 2% Ho + N» 5.2 17% Cp 0 bubbles over 400m length error-free 27% CO »55% HFO 1% Ho + N »5.3 0% Cp 0 bubbles over 350m length error-free 27% CO» 71% HFO 2% Ho + N »

The data show that high amounts of Cp lead to unusable insulated line pipes, whereas their partial or complete replacement by HFO leads to faultlessly insulated pipes.

While preferred embodiments of the invention are described in the present description, it should be pointed out that the invention is not restricted to these and can also be carried out in other ways within the scope of the following claims.

The invention is summarized in sentences # 1- # 21 below; these are not intended to limit the invention in any way:

# 1. Thermally insulated conduit pipe (1), comprising at least one medium pipe (4), at least one thermal insulation (3) arranged around the medium pipe and at least one outer jacket (2) arranged around the thermal insulation, characterized in that said outer jacket (2) optionally has a Barrier (9) made of plastic, and said thermal insulation (3) comprises a foam, the cell gas of which contains 10-100 vol% hydrofluoroolefins (HFOs) and 0-50 vol% (cyclo) alkanes and 0-50 vol% CO », and wherein said HFO is selected from the group comprising compounds of the formula (I)

RS

RS PA OF (I)

where R * ° and R® are independently H, F, Cl, CFs and where

said alkane is selected from the group comprising propane, butanes, (cyclo) pentanes, (cyclo) hexanes and where

said thermal insulation (3) a foam selected from the group of polyurethanes (PU), polyisocyanurates (PIR), thermoplastic polyesters (PET) and thermoplastic

cal polyolefins.

# 2.

Line pipe according to # 1, characterized in that said cell gas contains 10-100% by volume HFOs and 050% by volume (cyclo) alkanes and 0-50% by volume CO and the ratio of HFOs to (cyclo) alkanes being at least 2.5: 1.

# 3.

Line pipe according to one of # 1 or # 2, characterized in that said HFO is selected from the group comprising compounds of the formula (I) which stand for R1233zd and / or R1336mzz.

# 4. Line pipe according to # 1, characterized in that said thermal insulation (3) contains a foam material selected from the group of polyurethanes (PU).

# 5.

Line pipe according to one of # 1 to # 4, characterized in that S;

- PIR containing 50-100vol% R1233zd and 0-50vol% cyclopentane as cell gas;

- PIR containing 50-100vol% R1336mzz and 0-50vol% cyclopentane as cell gas;

- PET containing 50-100vol% R1233zd and 0-50vol% cyclopentane as cell gas;

- PET containing 50-100vol% R1336mzz and 0-50vol% cyclopentane as cell gas;

- PE containing 50-100vol% R1233zd and 0-50vol% cyclopentane as cell gas; and / or - PE containing 50-100% by volume R1336mzz and 0-50% by volume cyclopentane as cell gas.

# 6.

Line pipe according to one of # 1 to # 5, characterized in that a barrier (9) is present,

which is designed as a layer,

- which reduces the diffusion of gases out of the thermal insulation and into the thermal insulation, and

- which enables the diffusion of water out of the thermal insulation.

# 7.

Line pipe according to one of # 1 to # 6, characterized in that the barrier (9) - as a layer on the thermal insulation; and or

- as a layer on the inside of the outer jacket; and or

- Is arranged as a layer in the outer jacket.

# 8.

Line pipe according to one of # 1 to # 7, characterized in that the barrier (9)

- comprises a copolymer of ethylene and vinyl alcohol or a copolymer of ethylene and carbon monoxide or a copolymer of ethylene and carbon monoxide and propylene, and

- has a layer thickness of 0.05-0.5 mm.

# 9. Line pipe according to # 8, characterized in that the polymer contains 50-100% by weight, structural units of the formula (II) or (III) or (IV),

OH Q {IV}, {II}, {III}

where m is 1-10, n is 2-20, [with m / n 30/100 to 50/100], o is 1 or 2, preferably 1, p is 1 or 2, preferably 1 , q is 1-20 and r is 1-20.

# 10. Line pipe according to one of # 1 to 9, characterized in that said medium pipe (4)

GO CHx

- is a flexible plastic pipe, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, polybutene (PB), polyethylene raised temperature (PE-RT), and polyketone (PK); or

- is a flexible plastic pipe with an outer metal layer, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, polybutene (PB), polyethylene raised temperature (PE-RT), and polyketone (PK), the metal selected from the group aluminum; or

- is a rigid plastic pipe, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, PB, PERT, and PK; or

- is a flexible metal tube, the metal selected from the group copper including its alloys, iron including its alloys, aluminum including its alloys

- is a rigid metal tube, the metal selected from the group copper including its alloys, iron including its alloys, aluminum including its alloys.

# 11.

Line pipe according to one of # 1 to # 10, characterized in that

- said outer jacket (2) is designed as a corrugated pipe; and said medium pipe is designed as a flexible pipe section; or

- said conduit pipe is a rigid straight pipe section; or

- said outer jacket (2) is designed as a corrugated tube; and said medium pipe is preferably designed as a flexible pipe section.

# 12.

A method for producing a thermally insulated conduit pipe, said conduit pipe comprising at least one carrier pipe (4), at least one thermal insulation (3) arranged around the carrier pipe and at least one outer jacket (2) arranged around the thermal insulation, said outer jacket (2) being a Barrier (9) made of plastic, and wherein said thermal insulation (3) comprises a foam whose cell gas contains 10-100 vol% hydrofluoroolefins (HFOs) and 0-50 vol% (cyclo) alkanes and 0-50 vol% CO » , in particular a conduit pipe according to one of # 1 to 11, characterized in that the thermal insulation (3) is formed by foaming a plastic composition which contains polymer components for foam formation and HFO as a blowing agent.

# 13.

Method according to # 12, characterized in that

- That the plastic composition comprises two liquid components, the first component containing a polyol and HFO and the second component containing isocyanate; or

- That the plastic composition comprises two liquid components, the first component containing a polyol and the second component containing isocyanate and HFO; or

- that the plastic composition consists of a molten component and this melt is combined with HFO under pressure.

# 14.

Method according to # 12 or # 13 for producing a thermally insulated conduit pipe (1) with

at least one flexible medium pipe (4), a thermal insulation layer (3) and an outer

jacket (2), possibly with a barrier (9) made of plastic, wherein

(e) the at least one medium pipe is fed in continuously and covered with a plastic film shaped into a hose,

(ff) a foamable plastic composition is introduced into the space between the medium pipe and hose as a thermal insulation layer,

(g) the medium pipe and the hose are introduced into a tool formed from molded parts moving along and leave this tool at its end, and then

(h) the outer jacket is extruded onto the surface of the hose,

characterized in that the foamable plastic composition comprises the polymer

contains component (s) for foam formation and HFO as a blowing agent.

# 15.

Method according to # 14, characterized in that a barrier (9) is present and

- That the barrier is introduced between the foamed thermal insulation layer and the inside of the outer jacket by forming the hose from the polymer; or

- That the barrier is applied by coextrusion together with the outer jacket; or

- that the barrier is applied directly to the hose; or

- that first a layer of the outer jacket, followed by the barrier and followed by at least a second layer of the outer jacket is applied.

# 16.

Method for producing a thermally insulated conduit pipe (1) with at least one

rigid medium pipe (4), a thermal insulation layer (3) and an outer jacket (2), if necessary with a bar

riere (9) made of plastic, whereby

(a) a carrier pipe is centered within an outer pipe and

(b) a foamable plastic composition is introduced into the space between the carrier pipe and the outer pipe as a thermal insulation layer,

characterized in that the foamable plastic composition comprises the polymer

contains components for foam formation and HFO as a blowing agent.

# 17.

Method according to # 16, characterized in that there is a barrier (9) and

- That a barrier is introduced between the foamed thermal insulation layer and the outside of the outer jacket in the form of a hose; or

- That the barrier is applied to the inside of the outer tube; or

- That the barrier is provided in the outer tube; or

- That the barrier is applied to the outside of the outer tube.

# 18.

Covering device made of plastic or sleeve made of plastic for the connection of thermally insulated pipes, wherein the covering device or the sleeve has at least one thermal insulation (3) and at least one outer jacket (2) arranged around the thermal insulation, characterized in that

said outer jacket (2) comprises at least one barrier (9) made of plastic, and

said thermal insulation (3) comprises a foam whose cell gas contains at least 10% by volume of HFOs.

# 19. Use of hydrofluoroolefins as cell gas for foam insulation in thermally insulated pipe systems, especially in plastic medium pipe systems (PMR) and in plastic jacket pipe systems (KMP), said cell gas being 10-100 vol% hydrofluoroolefins (HFOs) and 0-50 vol% (cyclo) alkanes and 0 -50 vol% CO »contains, said HFO being selected from the group comprising compounds of the formula (I)

RE

RS De (x)

where R * ° and R® are independently H, F, Cl, CFs and said alkane is selected from the group comprising propane, butanes, (cyclo) pentanes, (cyclo) hexanes.

# 20. Use according to # 18 in conduits, covering devices and / or sleeves.

# 21. Pipe system containing thermal insulation, characterized in that said thermal insulation comprises a foam, the cell gas of which is defined as in # 19.

Claims (14)

Expectations 1. Thermally insulated pipe (1) for use in flexible pipe systems, comprising at least one medium pipe (4), at least one thermal insulation (3) arranged around the medium pipe and at least one outer jacket (2) arranged around the thermal insulation, characterized in that said medium pipe (4) is designed as a flexible pipe section, said outer casing (2) optionally comprises a barrier (9) made of plastic, and said thermal insulation (3) comprises a foam whose cell gas contains 10-100 vol% hydrofluoroolefins (HFOs) and 0-50 vol% (cyclo) alkanes and 0-50 vol% CO », and wherein said HFO is selected from the group comprising the compounds R1233zd, and / or R1336mzz and where said alkane is selected from the group comprising propane, butanes, (cyclo) pentanes, (cyclo) hexanes and where said thermal insulation (3) contains a foam selected from the group of the polyurethane (PU), the polyisocyanurate (PIR), the thermoplastic polyester (PET) and the thermoplastic polyolefine. 2. Pipe according to claim 1, characterized in that said cell gas contains 10-100 vol% HFOs and 0-50 vol% (cyclo) alkanes and 0-50 vol% CO »and with the proviso that the ratio of HFOs to ( Cyclo) alkanes is at least 2.5: 1. 3. Conduit pipe according to one of claims 1 or 2, characterized in that said HFO is selected from the group comprising R1233zd. 4. Conduit pipe according to one of claims 1 or 2, characterized in that said thermal insulation (3) contains a foam selected from the group of polyurethanes (PU). 5. Line pipe according to one of claims 1 to 4, characterized in that said cell gas contains 50-100 vol% HFOs. 6. Conduit pipe according to one of claims 1 to 5, characterized in that said thermal insulation (3) contains or consists of a closed-cell foam. 7. Conduit pipe according to one of claims 1 to 6, characterized in that said foam is selected from - PU containing 50-100% by volume R1233zd and 0-50% by volume cyclopentane as cell gas; or - PU containing 50-100% by volume R1336mzz and 0-50% by volume cyclopentane as cell gas. 8. Line pipe according to one of claims 1 to 7, characterized in that a barrier (9) is present, which - as a layer on the thermal insulation; and / or - as a layer on the inside of the outer jacket; and / or - is arranged as a layer in the outer jacket. 9. Line pipe according to one of claims 1 to 8, characterized in that the barrier (9) - a copolymer of ethylene and vinyl alcohol or a copolymer of ethylene and carbon includes lenmonoxide or a co-polymer of ethylene and carbon monoxide and propylene, and - has a layer thickness of 0.05-0.5 mm. 10. Line pipe according to one of claims 1 to 9, characterized in that said outer jacket is designed as a flexible pipe section. 11. Conduit pipe according to one of claims 1 to 10, characterized in that - said outer jacket (2) is designed as a corrugated pipe; or - said outer jacket (2) is designed as a smooth tube; or - said outer jacket (2) is designed as a corrugated tube. 12. Line pipe according to one of claims 1 to 11, characterized in that - said medium pipe (4) is a flexible plastic pipe, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, polybutene (PB), polyethylene raised temperature (PE-RT), and polyketone (PK); or - said medium pipe (4) is a flexible plastic pipe with an outer metal layer, the plastic selected from the group ABS, PEXa, PEXb, PEXc, PE, polybutene (PB), polyethylene raised temperature (PE-RT), and polyketone (PK) , the metal selected from the group aluminum; or - Said medium pipe (4) is a flexible metal pipe, the metal selected from the group copper including its alloys, iron including its alloys, aluminum including its alloys 13. Pipe system containing thermal insulation as defined in one of claims 1 to 7. 14. Plastic medium pipe system (PMR) containing thermal insulation as defined in one of claims 1 to 7. For this purpose 2 sheets of drawings