HEAT TRANSPORT MATERIAL WITH GOOD SOUND ABSORPTION PROPERTIES

Description

Technical area

[0001] The invention relates to a heat transport material which simultaneously has good sound absorption properties, and to its use. State of the art

[0002] Especially in modern buildings, even in temperate climates, it is often desirable to air-condition the rooms within the building by removing heat from the building or adding it to it. Heat removal is particularly important for rooms that are heavily frequented by people and / or equipped with numerous electronic devices, as these generate significant heat emissions in the three-digit watt range. The same applies, for example, to production halls, where machinery and equipment emit significant amounts of heat that must be removed from the building.

[0003] There are essentially different options for heat dissipation, with large-area air conditioning elements based on the heat radiation principle proving particularly suitable. State-of-the-art heat transfer devices or air conditioning elements are used for air conditioning rooms, particularly for cooling. Such air conditioning elements are also, in principle, suitable for space heating if the heat transfer direction is reversed.

[0004] Ceiling or wall elements are already known from the prior art which have a frame which can be attached to the ceiling or wall, with a base plate and a heating or cooling register arranged in the frame. DE 20 2007 010 215 U1, for example, discloses a wall or ceiling cladding with a heating or cooling register in the form of pipes which are attached to heat-conducting profiles. The heat-conducting profiles lie on the back of a cladding surface formed by cladding panels. The cladding panels are attached to support rails with a U-shaped cross-section. The support rails and the cladding panels attached to them thus form a frame which can be attached to a ceiling or wall, with a base formed by the cladding panels. The heat-conducting profiles are arranged inside this frame and lie against the cladding panels.The heat-conducting profiles and the attached pipes form the heating or cooling register. To ensure good heat-conducting contact between the pipes and the cladding surface, clamps are arranged transversely to the elongated heat-conducting profiles. These clamps, under spring tension, hold at least two adjacent heat-conducting profiles against the cladding panel.

[0005] The heat-conducting profiles have a roughly semicircular neck on their back, within which the pipes are arranged. Depending on the application, a heating or cooling medium, such as hot or cold water, flows through the pipes. The heat-conducting profiles are usually made of metal, such as aluminum. The cladding panels can be plasterboard or perforated metal cassettes made of steel or aluminum.

[0006] To enable more efficient heat transfer between the heating or cooling register and the room to be heated or cooled, DE 10 2009 055 440 A1 proposes a ceiling or wall element for attachment to a ceiling or wall. The ceiling or wall element has a frame that can be attached to the ceiling (or wall) and has a base in which a heating or cooling register is arranged. A fleece and a graphite foil are arranged between the base of the frame and the heating or cooling register. The perforated graphite foil is intended to ensure good thermal contact between the heating or cooling register and the base plate of the ceiling or wall element, and the fleece is intended to improve the sound absorption of the ceiling or wall element. A carbon fiber fleece is presented as the preferred fleece because of its high thermal conductivity.Preferably, the nonwoven fabric and the perforated graphite foil arranged thereon are a composite which can be produced by calendering.

[0007] A disadvantage of the described heat transfer material is that heat transfer must be accomplished vertically via the carbon fiber mat, since the graphite foil only allows for surface heat conduction. However, carbon fiber mats are undesirable in building applications for health reasons and are unattractive in terms of price. Another disadvantage of using a foil is that it must be perforated to become sound-permeable and acoustically effective. This causes foils to tear quickly and become brittle.

[0008] EP 2 468 974 A2 is also based on the object of improving heat transfer in heating or cooling elements. To this end, this document proposes a structure for a heating or cooling element, in particular for an air-conditioned ceiling, comprising a perforated, heat-conducting carrier plate, on the rear of which run lines of a heating or cooling register that are in heat-conducting contact with the carrier plate. The rear of the carrier plate and the heating or cooling lines are covered by a cover sheet that has a textile or grid-like structure and is made of a heat-conducting material or is coated with a heat-conducting material.

[0009] A nonwoven fabric made of graphite or coated with graphite can be used as a cover sheet. This nonwoven fabric does not exhibit any special acoustic properties. Therefore, to improve the acoustics, we recommend laminating an additional acoustic nonwoven fabric to the back of the cover sheet.

[0010] EP 2 191 058 B1 describes a layer for use in a metal ceiling, with a maximum weight of 45 g / m², comprising a fiber blend present in a proportion of no more than 30 g / m² and a flame retardant present in a proportion of no more than 10 g / m². The layer exhibits good acoustic properties due to its high and defined porosity. However, due to its high porosity, the layer is only partially suitable for applications where thermal conduction is paramount. Description of the invention

[0011] The invention is based on the object of providing a material which, with a simple structure, combines very good heat-conducting properties with very good acoustic properties and can thus be used for heat transport and sound absorption, for example in the above-mentioned heat transfer devices.

[0012] This object is achieved by a heat transport material according to claim 1.

[0013] Surprisingly, it was discovered that the heat transfer material according to the invention combines excellent thermal conductivity with excellent acoustic properties. The heat transfer material can have a very simple and thin structure.

[0014] The proportion of graphite in the thermally conductive coating is more than 50 wt.%, for example, from 50 to 100 wt.%, more preferably from 60 to 100 wt.%, even more preferably from 70 to 100 wt.%, even more preferably from 80 to 100 wt.%. This is advantageous because it can significantly improve the thermally conductive properties of the textile fabric. Accordingly, good thermal conductivity can be achieved even with small application quantities. Small application quantities are, in turn, advantageous because they have less impact on the porosity and air permeability of the textile fabric.

[0015] In contrast, thermally conductive coatings of textile fabrics known from the prior art usually contain a smaller amount of graphite, since the graphite layer usually contains more than 50 wt.% binder.

[0016] The advantage of using a thermally conductive coating over films is that it can at least partially penetrate the textile material. Penetration into the material, in turn, is that heat transfer in the direction of the surface normal is improved. Accordingly, the thermally conductive coating has at least partially penetrated the textile fabric.

[0017] An advantage of the thermally conductive coating compared to perforated metal sheets is that improved bondability can be achieved due to the faster and more even distribution of heat in the textile fabric that it enables.

[0018] In a preferred embodiment of the invention, the high proportion of graphite in the thermally conductive coating is achieved by having the textile fabric comprise fibers made of a hydrophilic fiber material. Without committing to a specific mechanism, it is assumed that the hydrophilic fiber material has a high affinity and, therefore, particularly good adhesion to the graphite. This makes it possible to keep the proportion of binder in the thermally conductive coating and / or between the thermally conductive coating and the textile fabric very low. Nevertheless, the thermally conductive coating may contain binders.Examples of binders are polymeric binders from the group of acrylates, vinyl acrylates, vinyl acetates, ethylene vinyl acetates (EVA), acrylonitrile butadienes (NBR), styrene butadienes (SBR), acrylonitrile butadienes styrenes (ABS), vinyl chlorides, ethylene vinyl chlorides, polyvinyl alcohols, polyurethanes, starch derivatives, cellulose derivatives and their mixtures and / or copolymers. In a preferred embodiment of the invention, the proportion of polymeric binder, and in particular of the aforementioned polymeric binders, in the heat-conducting coating and / or between the heat-conducting coating and the textile fabric is less than 50% by weight, for example from 1 to 50% by weight, preferably less than 40% by weight, for example from 1 to 40% by weight, even more preferably less than 30% by weight, for example from 1 to 30% by weight and in particular less than 20% by weight, for example from 1 to 20% by weight.The advantage of using only a small proportion of polymer binder or of omitting it altogether is improved fire behavior of the material in the event of a fire as well as improved acoustic properties.

[0019] In a preferred embodiment of the invention, the proportion of graphite, based on the total weight of the heat transport material, is from 10 wt.% to 50 wt.%, more preferably from 10 wt.% to 35 wt.%, even more preferably from 10 wt.% to 20 wt.%.

[0020] In a further preferred embodiment of the invention, the thermally conductive coating is present in the form of a pattern on the textile fabric. This means that areas of the surface of the textile fabric are covered with the thermally conductive coating and other areas are not. The thermally conductive coating has also penetrated at least partially into the textile fabric. The advantage of forming a pattern is that the covered areas provide the heat transport material with high thermal conductivity, while the uncoated areas are particularly acoustically active because their porosity is not reduced by being provided with the thermally conductive coating. The pattern can be a geometric or irregular pattern. The surface coverage of the thermally conductive coating in relation to the surface of the heat transport material is advantageously 1 to 95%, preferably 10 to 60%, particularly preferably 30 to 50%.In a preferred embodiment, the pattern has at least partially continuous lines, preferably with a line width of > 0.5 mm, preferably from 2.0 to 10.0 mm, particularly preferably from 4.0 to 7.0 mm. This continuous pattern allows for good thermal conductivity to be achieved across the surface of the heat-transfer material.

[0021] In a further preferred embodiment, the pattern comprises at least partially discrete dots, rods, and / or discontinuous areas, preferably with a size of < 100 mm 2 , particularly preferably from 1.0 to 50 mm 2 , and in particular from 2.0 to 10 mm 2 . Practical tests have shown that this leads to rapid heat transfer through the thickness of the material, i.e., perpendicular to the plane of the textile fabric.

[0022] The heat transfer material according to the invention is further characterized by excellent acoustic properties. The heat transfer material has a flow resistance of 60 Pa*s / m to 400 Pa*s / m, more preferably 100 Pa*s / m to 300 Pa*s / m, and even more preferably 120 Pa*s / m to 250 Pa*s / m. The flow resistance is measured according to DIN EN 29053-A: 1993-05. By reducing the proportion of the polymeric binder or by completely omitting it, the negative influence of the heat-conducting coating on the acoustic properties of the material is reduced. Complete sealing of the surface can thus be prevented, maintaining sufficient porosity for acoustic effectiveness.The flow resistance can be adjusted in a manner known to those skilled in the art, for example by appropriately selecting the fiber materials in coordination with the selected parameters during production and coating of the textile fabric. It has been shown that particularly good sound absorption is possible with the flow resistances selected according to the invention. Thus, the sound absorption coefficient α(0) of the heat transfer material according to the invention, measured in an impedance tube at 1600 Hz, is preferably more than 0.55, for example from 0.55 to 1.0, more preferably more than 0.60, for example from 0.6 to 1.0, and in particular more than 0.65, for example from 0.65 to 1.0. The sound absorption coefficient is determined in accordance with DIN EN ISO 10534-1: 2001-10 using the parameters specified in Example 2.

[0023] According to the invention, the textile fabric preferably contains fibers selected from the group consisting of glass fibers, polyolefins, polyesters, in particular polyethylene terephthalate, polybutylene terephthalate; polyamide, in particular polyamide 6.6 (Nylon ®< ), polyamide 6.0 (Perlon ®< ), aramid, wool, cotton, silk, hemp, bamboo, kenaf, sisal, cellulose, soy, flax, glass, basalt, carbon, viscose, and mixtures thereof. According to the invention, the fiber material particularly preferably contains glass fibers, cellulose, and / or mixtures thereof, in particular glass fibers and cellulose.

[0024] The textile fabric may also contain conductive fibers, e.g. metal fibers, ceramic fibers, carbon fibers, etc., to further improve thermal conductivity.

[0025] Cellulose fibers are particularly preferred according to the invention. Cellulose fibers are understood to mean fibers that contain cellulose, viscose, and / or fine-fiber or fibrillated cellulosic components, so-called fiber pulp or wood pulp. The fibers particularly preferably consist essentially of the aforementioned components, i.e., their proportion is more than 80% by weight.

[0026] In a preferred embodiment of the invention, the textile fabric contains a proportion of at least 30 wt.%, for example from 30 to 100 wt.%, and / or from 30 to 95 wt.%, preferably from 50 to 100 wt.%, and / or from 50 to 90 wt.%, even more preferably from 60 to 95 wt.%, and in particular from 65 to 85 wt.% of cellulose fibers, in each case based on the total amount of fiber material in the textile fabric.

[0027] In a further preferred embodiment of the invention, the textile fabric contains glass fibers, preferably in an amount of 5 to 80 wt.%, more preferably 5 to 70 wt.%, even more preferably 10 to 60 wt.%, in particular 20 to 40 wt.%, in each case based on the total amount of fiber material in the textile fabric. The addition of glass fibers can provide the textile fabric with particularly high structural stability and low thermal shrinkage.

[0028] Most preferably, the textile fabric contains cellulose fibers, preferably in a proportion of 30 to 95 wt.%, more preferably 50 to 90 wt.%, in particular 65 to 85 wt.%, and glass fibers, preferably in a proportion of 5 to 70 wt.%, more preferably 10 to 50 wt.%, in particular 15 to 35 wt.%, in each case based on the total amount of fiber material in the textile fabric.

[0029] The textile fabric could be designed as a nonwoven, nonwoven fabric, or paper. According to the invention, a nonwoven fabric according to DIN EN ISO 9092 is preferably used.

[0030] To produce the nonwoven fabric, a dry nonwoven can be laid in a manner known to those skilled in the art using a carding process, a wet-laying process, or a spunbond process. Preferably, the nonwoven fabric is laid in a wet-laying process or a carding process. This allows for particularly high uniformity to be achieved, which is crucial for the acoustic properties. Accordingly, the nonwoven fabric is preferably a wet-laying process or a carded nonwoven fabric. Particularly preferably, the nonwoven fabric is laid in a wet-laying process, in particular using an inclined screen, since this allows for nonwovens with particularly high uniformity to be obtained.

[0031] The fiber mixture in the wet-laid nonwoven process could also contain fine-fiber or fibrillated cellulosic components, so-called fiber pulp or cellulose. These components enable very effective tuning of the acoustic effectiveness of the textile fabric. In a preferred embodiment, the nonwoven fabric is therefore a wet-laid nonwoven fabric containing fiber pulp, in particular cellulose pulp, and / or cellulose, preferably in a proportion of at least 30 wt.%, for example from 30 to 100 wt.% and / or from 30 to 95 wt.%, preferably from 50 to 100 wt.%, and / or from 50 to 90 wt.%, even more preferably from 60 to 95 wt.%, and in particular from 65 to 85 wt.%, in each case based on the total amount of fiber material in the wet-laid nonwoven fabric.

[0032] Against this background, it is conceivable that the wet-laid nonwoven fabric contains two or more different fiber pulp and / or cellulose types that differ in their fineness. This allows for a particularly precise adjustment of the porosity and, consequently, a textile fabric with particularly effective acoustic flow resistance. It is also conceivable that the wet-laid nonwoven fabric contains finely ground synthetic pulps, e.g., made from viscose, polyolefin, and / or aramid fibers.

[0033] The nonwoven fabric can be mechanically, chemically, and / or thermally bonded to form the nonwoven fabric in a known manner. Chemical bonding using a polymeric binder is particularly preferred. Preferred fiber binders are polyacrylates, polyvinyl acrylates, polystyrene acrylates, polyvinyl acetates, polyethylene vinyl acetates (EVA), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), acrylonitrile butadiene styrene rubber (ABS), polyvinyl chlorides, polyvinylethylene vinyl chlorides, polyvinyl alcohols, polyurethanes, starch derivatives, cellulose derivatives, and their copolymers and / or mixtures. Accordingly, the nonwoven fabric is preferably a chemically bonded nonwoven fabric. The fiber binder enables the textile fabric to be obtained with high strength and good aging resistance. The fiber binder can be applied by impregnation, spraying, or other conventional application methods.

[0034] The fiber binder may also contain conventional additives such as flame retardants, e.g., metal hydroxides such as aluminum hydroxide, diammonium hydrogen phosphate, or other nitrogen- and / or phosphorus-based flame retardants, such as ammonium polyphosphates or nitrogen-containing phosphoric acid salts. These can be incorporated into the impregnation mixture via the fiber binder for fiber bonding.

[0035] The proportion of fiber binder including the additives in the heat transport material is preferably from 10 to 70 wt.%, more preferably from 20 to 50 wt.%, and in particular from 30 to 40 wt.% based on the total weight of the heat transport material.

[0036] The textile fabric can also contain corrosion inhibitors: Condensation moisture in the cooling ceiling application can lead to damage to metal elements, such as aluminum profiles, etc. The addition of a corrosion inhibitor can counteract this.

[0037] Additionally, the textile fabric can be treated with an antimicrobial biocidal additive. Condensation can lead to bacterial and fungal growth in the textile fabric during use, which can be prevented with this treatment.

[0038] The basis weight of the heat transfer material is preferably from 20 to 100 g / m², more preferably from 40 to 70 g / m², and especially from 45 to 60 g / m², each measured according to ISO 9073-1. For good fire behavior and good acoustic properties, a material with low basis weights, thus requiring minimal material usage, is recommended.

[0039] The thickness of the heat transfer material is preferably from 0.1 to 0.5 mm, more preferably from 0.15 to 0.4 mm, and especially from 0.2 to 0.3 mm, each measured according to ISO 9073-2. The advantage of a thin material that simultaneously exhibits good acoustic properties is that it facilitates processing, i.e., laminating the material in perforated metal ceilings.

[0040] The air permeability of the heat transfer material is preferably from 100 to 3000 l / m 2 / s, more preferably from 200 to 1000 l / m 2 / s, and especially from 300 to 700 l / m 2 / s, each measured according to DIN EN ISO 9237 at 100 Pa air pressure. These air permeabilities result in particularly good acoustic properties.

[0041] The tensile strength in at least one direction, preferably in the machine direction, of the heat transfer material is preferably from 20 to 300 N / 5cm, more preferably from 30 to 150 N / 5cm, and in particular from 50 to 100 N / 5cm, each measured according to ISO 9073-3.

[0042] In a preferred embodiment of the invention, the textile fabric is metallized. Metallization can be achieved, for example, through a vacuum deposition process or electroplating. Aluminum, copper, copper alloys, stainless steel, gold, and / or silver have proven particularly suitable metals. Stainless steel is particularly preferred, as this imparts particularly high aging resistance to the textile fabric. Additionally, it can be treated with a corrosion inhibitor.

[0043] According to the invention, the heat transfer material has a thermally conductive coating containing graphite. "Graphite" is understood, in accordance with the invention, to mean not only graphite in the narrower sense but also graphite-analogous compounds, such as, in particular, expanded graphite, graphene, and hexagonal boron nitride. In a preferred embodiment, the graphite is selected from graphite in the form of a material with multiple crystal planes and graphene, i.e., a material with only a single crystal plane. The graphite is preferably in particle form. The average size of the graphite particles can preferably be 0.5 to 10 micrometers, particularly preferably 1 to 3 micrometers. Practical tests have shown that this results in a good compromise between processability and thermal conductivity. Large graphite particles are advantageous for good thermal conductivity, but are more difficult to process and preferentially remain on the surface of the textile fabric.This leads to a low penetration depth of the graphite into the heat transfer material, which leads to a reduced conductivity perpendicular to the surface plane.

[0044] In one embodiment of the invention, the application weight of the thermally conductive coating is 1 to 50 g / m², preferably 2 to 30 g / m², particularly preferably 5 to 15 g / m². Practical tests have shown that even with a low application weight of graphite, a significant improvement in thermal conductivity can be observed. At the same time, good acoustic properties can be achieved because the porosity of the material is maintained.

[0045] The thermally conductive coating is preferably applied by treating the textile fabric with an aqueous graphite dispersion and then drying it.

[0046] A binder, for example a polymeric binder, can be added to the graphite dispersion in order to improve the bonding to the textile fabric, e.g. polyacrylates, polyvinyl acrylates, polyvinyl acetates, polyethylene vinyl acetates (EVA), acrylonitrile butadienes (NBR), styrene butadienes (SBR), acrylonitrile butadienes styrenes (ABS), vinyl chlorides, ethylene vinyl chlorides, polyvinyl alcohols, polyurethanes, starch derivatives, cellulose derivatives and mixtures and / or copolymers thereof.

[0047] The graphite dispersion may be mixed with other additives, e.g., defoamers, wetting agents, surfactants to facilitate processing, bases and / or acids to adjust the pH, flame retardants, corrosion inhibitors, and / or biocides. A wetting agent selected from the group consisting of: glycerin, propylene glycol, sorbitol, trihydroxystearin, phospholipids, ethylene oxide / fatty alcohol ethers, ethoxylates of propylene oxide with propylene glycol, esters of sorbitol and / or glycerin, alkyl sulfonates, alkyl sulfosuccinates, docusates, and mixtures thereof is preferably used.

[0048] Practical tests have shown that with a proportion of the wetting agent based on the total amount of the graphite dispersion in the range of 0.1 to 5 wt.%, preferably 1 to 4 wt.%, in particular 1.5 to 3.5 wt.%, a particularly uniform and homogeneous wetting and a particularly good penetration into the material is achieved.

[0049] The finishing can be carried out using all common finishing methods for flat materials, for example by impregnation, e.g. using a padder; by printing, e.g. flat or screen printing, rotary stencil printing; kiss coating, doctor blade, etc.; spraying; the finishing can be done on one or both sides. Covering, e.g. printing, is particularly preferred, especially by screen printing or rotary stencil printing. In this way, the thermally conductive coating can be applied to the textile fabric, e.g. as a pattern print. The heat transfer material then has high thermal conductivity locally in the printed area, while the unprinted areas are particularly acoustically active because their porosity is not impaired by the finishing with the thermally conductive coating.The surface coverage of the heat-transfer material by the heat-conductive coating in the form of a pattern is preferably 1 to 100%, preferably 10 to 60%, particularly preferably 30 to 50%. In a preferred embodiment, the printing is carried out at least partially in the form of continuous lines, preferably with a line width of > 0.5 mm, preferably 2.0 to 10.0 mm, particularly preferably 4.0 to 7.0 mm. This ensures rapid heat distribution in the plane of the textile fabric.

[0050] In a further preferred embodiment, the printing can be carried out at least partially in the form of discrete dots, rods, and / or discontinuous areas, preferably with a size of < 100 mm 2 , particularly preferably from 1.0 to 50 mm 2 , and in particular from 2.0 to 10 mm 2 . Practical tests have shown that this leads to rapid heat transfer through the thickness of the material, i.e., perpendicular to the plane of the textile fabric.

[0051] Drying can be achieved using all common drying methods, e.g., contact drying with a roller dryer, circulating air or through-air drying with a belt dryer, IR or microwave drying, etc. Through-air drying is preferred to preserve the porosity of the material and thus its good acoustic properties. The material can also be post-treated with compression rollers to further improve the contact between the graphite particles and thus the thermal conductivity of the material.

[0052] In a preferred embodiment of the invention, the heat transfer material has an additional, preferably discontinuous, adhesive coating. The adhesive coating preferably consists of a hot-melt adhesive. The advantage of the discontinuous adhesive coating is that it does not significantly impair the acoustic effectiveness of the heat transfer material. The adhesive coating can be applied, for example, by sprinkling a hot-melt adhesive powder onto the heat transfer material and subsequently thermally fixing it to the heat transfer material. The hot-melt adhesive advantageously has a melting point of <125°C.

[0053] The basis weight of the adhesive coating is preferably from 5 to 50 g / m 2< , more preferably from 10 to 40 g / m 2< , particularly preferably from 12 to 25 g / m 2< .

[0054] The adhesive coating preferably consists essentially of a thermoplastic polymer, e.g., a largely amorphous polyester or copolyester, a polyamide or copolyamide, a polyurethane, a polyolefin, polyethylene-vinyl acetate, and / or mixtures, copolymers, or terpolymers thereof. "Essentially" means a proportion of at least 70 wt.%, preferably more than 80 wt.%, based on the total mass of the adhesive coating.

[0055] The adhesive coating can additionally be provided with thermally conductive additives, e.g. by compounding the thermoplastic polymer with thermally conductive fillers (e.g. carbon black, graphite, metal powders, metal oxides, boron nitride, ceramic compounds, etc.) in order to further increase the thermal conductivity of the heat transport material according to the invention.

[0056] If the adhesive coating is applied to the textile fabric in powder form, the powder can be processed as a mixture with other thermally conductive powders (e.g., metal powders, fine metal spheres, metal oxide powders, ceramic powders, etc.) to further increase the thermal conductivity of the heat transfer material. The adhesive coating can also contain a ceramic reactive adhesive, which, for example, contains reactive silane groups.

[0057] The heat transfer material according to the invention is ideally suited for heat transfer and simultaneous sound absorption in ceiling and / or wall elements, in particular comprising a frame that can be attached to the ceiling and / or wall and has a base in which a heating and / or cooling element is arranged. The heat transfer material according to the invention is preferably arranged between the base of the frame and the heating or cooling element.

[0058] The ceiling and / or wall elements could be used in suspended, perforated, and / or slotted metal ceiling and / or wall systems (including wood or plasterboard ceilings). The use of the heat transfer material according to the invention in the construction of raised floors is also conceivable.

[0059] The invention is explained in more detail below using several examples. Example 1: Production of a heat transport material according to the invention

[0060] To produce a heat transfer material according to the invention, a textile fabric in the form of a wet-laid nonwoven is first produced. The total basis weight of the wet-laid nonwoven is 48 g / m². The textile fabric comprises a fiber blend of 70 wt.% cellulose and 30 wt.% glass fibers. The fiber blend contributes a total of 25 g / m² to the basis weight of the textile fabric. Furthermore, the textile fabric comprises a fiber binder made of a polyacrylate binder and flame retardant, contributing 23 g / m² to the basis weight.

[0061] A commercially available graphite dispersion with an average particle diameter of 2.5 micrometers and a solids content of 18 wt.% is used to produce the thermally conductive coating. It is applied using rotary stencil printing and subsequent drying in a through-air oven. A rectangular diamond pattern is chosen as the stencil pattern. The average width of the printed lines on the wet-laid nonwoven is 5.0 mm, and the surface coverage by the thermally conductive coating is 52%. The proportion of graphite in the thermally conductive coating, measured according to Example 4, is 80 wt.%, which corresponds to 14 wt.% of the total weight of the heat transfer material.

[0062] The obtained heat transfer material has a total weight of 57 g / m 2< , a thickness of 0.23 mm, a tensile strength in the machine direction of 65 N / 5 cm, an air permeability at 100 Pa of 550 l / m 2< / s and a flow resistance of 190 Pa*s / m. Example 2: Determination of the sound absorption coefficient of the heat transfer material

[0063] For impedance tube tests, the heat transfer material is coated with an adhesive. The adhesive consists of epsilon-polycaprolactone, which is powdered onto the heat transfer material as a ground powder with an average grain size of 150 micrometers and sintered in a furnace. The application rate is 15 g / m².

[0064] The heat transfer material coated with the adhesive is then ironed onto a perforated, painted steel sheet with a thickness of 0.5 mm, a perforation area of 15%, and a perforation diameter of 2.3 mm. The sound absorption coefficient is determined on the composite material and reported as α(0) at a frequency of 1600 Hz.

[0065] A sound absorption coefficient of α(0) = 0.7 is determined at 1600 Hz. Example 3: Determination of the thermal conductivity of the heat transfer material

[0066] The thermal conductivity of the heat transfer material is compared to the textile fabric without a thermally conductive coating. The measurements are carried out using the plate method according to DIN 52612 on six-layer stacked test specimens and the hot disk method on a single layer according to ISO 22007-2.2:2008, Part 2. Method thermal conductivity Unit Textile fabric Heat transport material Plate method W / (K*m) 0,06 0,08 Hotdisk W / (K*m) 0,06 0,09 Example 4: Qualitative and quantitative determination of graphite

[0067] Qualitative identification of the graphite is performed using angled X-ray scattering (XRD) according to DIN EN 13925-2 2003-07. X-ray diffractograms of the heat transfer material are recorded using CoKα radiation at 40 kV and 35 mA in the angle range 5° to 60° (2 theta). Clear identification can be achieved via the sharp reflections at 30.78° (3.37 Å); 49.69° (2.13 Å); 52.19° (2.04 Å); 64.37° (1.68 Å); and 93.21° (1.23 Å). Quantitative determination of the graphite content in the heat transfer material or the thermally conductive coating can be performed using thermogravimetric analysis (TGA) according to DIN EN ISO 11358 2014-10. The sample is first heated to 1000°C in an inert nitrogen atmosphere and then cooled back to 300°C. The sample is then heated again to 1000°C in oxygen. This final combustion step burns the graphite and (if present) the soot.Soot burns in a temperature range from 380°C to 700°C, and graphite at temperatures > 700°C. If the combustion of soot is not completely separated from that of graphite, the derivation of the thermogravimetric curve, which then shows a turning point at 700°C, is used to determine the temperature ranges to be evaluated.

Claims

1. Heat transport material having a flow resistance of 60 Pa*s / m to 400 Pa*s / m, more preferably from 100 Pa*s / m to 300 Pa*s / m, more preferably still from 120 Pa*s / m to 250 Pa*s / m, which comprises a sheetlike textile structure and a graphite-containing heat-conducting coating, wherein the graphite is contained in a fraction of 5% to 50%, by weight, based on the total weight of the heat transport material, wherein the fraction of graphite in relation to the heat-conducting coating is more than 50% by weight, characterized in that the heat-conducting coating has at least partly penetrated into the sheetlike textile structure.

2. Heat transport material according to Claim 1, characterized in that the heat-conducting coating comprises a polymeric binder, wherein the fraction of polymeric binder in the heat-conducting coating is less than 40% by weight.

3. Heat transport material according to Claim 1 or 2, characterized in that the sheetlike textile structure comprises fibres composed of a hydrophilic fibre material.

4. Heat transport material according to one or more of the preceding claims, characterized in that the heat-conducting coating is in the form of a pattern on the sheetlike textile structure.

5. Heat transport material according to Claim 4, characterized in that the pattern comprises at least partially continuous lines.

6. Heat transport material according to one or more of the preceding claims, characterized in that the applied weight of the heat-conducting coating is 1 to 50 g / m2.

7. Heat transport material according to one or more of the preceding claims, characterized in that the graphite is in particle form with an average particle size of 0.5 to 10 µm.

8. Heat transport material according to one or more of the preceding claims, characterized by a sound absorption coefficient, measured in an impedance tube at 1600 Hz, of more than 0.55.

9. Heat transport material according to one or more of the preceding claims, characterized in that the sheetlike textile structure contains a fraction of at least 30% by weight of cellulose fibres, based on the total amount of fibre material in the sheetlike textile structure.

10. Heat transport material according to one or more of the preceding Claims 1-8, characterized in that the sheetlike textile structure contains glass fibres in a fraction of 5% to 80% by weight, based on the total amount of fibre material in the sheetlike textile structure.

11. Heat transport material according to one or more of the preceding claims, characterized in that the sheetlike textile structure is a wetlaid nonwoven fabric or a carded nonwoven fabric.

12. Heat transport material according to one or more of the preceding claims, characterized by a surface weight of 20 to 100 g / m2 and / or by a thickness of 0.1 to 0.5 mm and / or by an air permeability of 100 to 3000 l / m2 / s.

13. Heat transport material according to one or more of the preceding claims, characterized in that it comprises a hotmelt adhesive in the form of a preferably discontinuous coating of adhesive compound.

14. Use of a heat transport material according to one or more of the preceding claims for heat transport and simultaneous sound absorption in ceiling and / or wall elements, preferably comprising a frame which can be fastened to the ceiling and / or the wall and has a bottom in which a heating and / or cooling element is arranged.