CA3050885C

CA3050885C - Heat transfer material with good sound absorption properties

Info

Publication number: CA3050885C
Application number: CA3050885A
Authority: CA
Inventors: Dominic Kramer; Jochen Bechtum; Rudolf Wagner; Sarah SENNE; Guenter Frey; Werner Kattge; Hartwig Von Der Muehlen; Matthias Herzog; Maria Teresa RODRIGUEZ CHARLES
Original assignee: Carl Freudenberg KG
Current assignee: Carl Freudenberg KG
Priority date: 2018-08-24
Filing date: 2019-07-30
Publication date: 2021-12-28
Anticipated expiration: 2039-07-30
Also published as: TW202009288A; SG10201907678SA; US20200063335A1; DE102018120713A1; KR20200023180A; CA3050885A1; EP3613913A1; CN110857535A

Abstract

Heat transfer material with a flow resistance from 60Pa*s/m to 400Pa*s/m, more preferably from 100Pes/m to 300Pa*s/m, even more preferably from 120Pa*s/m to 250Pa*s/m, having a textile fabric and a graphite-containing heat-conducting coating, wherein the graphite is present in an amount from 5% w/w to 50% w/w, based on the overall weight of the heat transfer material.

Description

HEAT TRANSFER MATERIAL WITH GOOD SOUND ABSORPTION PROPERTIES
Description Technical area The invention relates to a heat transfer material which has good sound absorption properties, as well as its use.
Prior art Particularly in modern buildings, it is often desirable, even in temperate climate zones, to air-condition the rooms of the building by dissipating heat from or feeding heat to the building. In such case, heat dissipation is particularly important for rooms heavily frequented by people and/or equipped with numerous electronic devices because they exhibit a significant heat dissipation in the three-digit watt range. The same applies, for example, to production halls, where machines and systems emit considerable amounts of heat that have to be dissipated from the building.
In principle, there are different options for heat dissipation, wherein large-area air-conditioning elements based on the principle of heat dissipation have proven to be particularly suitable. For the air-conditioning of rooms, in particular for room cooling, heat transfer devices or air-conditioning elements, which are known from the prior art, are used. In principle, such air-conditioning elements are also suitable for space heating when the heat transfer direction is reversed.
Ceiling or wall elements, having a frame with a base plate which can be fastened to the ceiling or the wall, and having a heating or cooling register arranged in the frame, are already known from the prior art. For example, from DE 20 2007 010 215 U1, a wall or ceiling cladding with a heating or cooling register in the form of pipes, which are attached to heat-conducting profiles, is known. On the rear side, the heat-conducting profiles bear against 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 thereto thus form a frame which is attachable to a ceiling or a wall and which has a base formed by the cladding panels. The heat-conducting profiles are arranged in the interior of said frame and bear against the cladding panels. The heat-conducting profiles and the pipes attached thereto form the heating or cooling register. In order to produce a good heat-conducting contact between the pipes and the cladding surface, hold-down devices are arranged transversely to the elongated heat-, =

2 conducting profiles, which, under spring tension, hold at least two adjacent heat-conducting profiles to bear against the cladding panel.
On their rear side, the heat-conducting profiles have an approximately semicircular step, in .. which the pipes are arranged. Depending on the intended use as heating or cooling line, a heating or cooling medium, e.g., hot or cold water, flows through the pipes. The heat-conducting profiles are usually made of metal, such as aluminum. The cladding panels, for example, can be drywall panels or perforated metal cassettes made of steel or aluminum.
In order to allow for a more efficient heat transfer between the heating or cooling register and the space to be heated or cooled, DE 10 2009 055 440 Al proposes a ceiling or wall element for attachment to a ceiling or a wall, wherein the ceiling or wall element comprises a frame, which has a base, is attachable to the ceiling (or the wall), and in which a heating or cooling register is arranged, and wherein, between the base of the frame and the heating or cooling register, a non-woven material and .. a graphite sheet are arranged. The perforated graphite sheet is supposed to ensure good thermal contact between the heating or cooling register and the base plate of the ceiling or wall element, and the non-woven material is supposed to improve the sound absorption of the ceiling or wall element. A
carbon fiber non-woven material is described as the preferred non-woven material because of its high heat conductivity. The non-woven material and the perforated graphite sheet arranged thereon are preferably a composite which can be produced by calendering.
The heat transfer material described is disadvantageous because the heat transfer in the vertical direction must be accomplished via the carbon fiber non-woven material, since the graphite sheet only allows for a planar heat conduction. For health reasons, carbon fiber non-woven materials .. are undesirable in building applications and unattractive in terms of price. In addition, the use of a film is disadvantageous because it must be perforated in order to be sound-permeable and acoustically effective. As a result, films tear quickly and are brittle.
EP 2 468 974 A2 also addresses the problem of achieving an improvement of the heat transfer in heating or cooling elements. For this purpose, this document proposes a structure for a heating or cooling element, in particular for an air-handling ceiling, comprising a perforated, heat-conducting carrier plate with lines of a heating or cooling register running on its rear side, said lines being in heat-conductive contact with the carrier plate, wherein the rear side of the carrier plate and the heating or cooling lines are covered by a covering path which has a textile or grid-shaped structure and consists of a heat-conducting material or is coated with a heat-conducting material.

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3 A non-woven material made of or coated with graphite, for example, can be used as a covering path. This non-woven material has no special acoustic properties. In order to improve the acoustics, it is therefore proposed that an acoustic non-woven material is additionally laminated onto the rear side of the covering path.
EP 2 191 058B1 describes a layer for use in a metal ceiling, having a basis weight of maximally 45g/m2, comprising a fiber mixture which is present in an amount of maximally 30g/m2, and a flame retardant which is present in an amount of maximally 10g/m2. The layer has good acoustic properties because it has a high and defined porosity. Due to its high porosity, however, the layer is suitable only to a limited extent for applications, in which heat conduction has priority.
Description of the invention The invention addresses the problem of providing a material which, with a simple structure, combines very good heat-conducting properties with very good acoustic properties and, as a result, can be used for heat transfer and sound absorption, for example, in the above-mentioned heat transfer devices.
This problem is solved by a heat transfer material with a flow resistance from 60Pa*s/m to 400Pa*s/m, preferably from 100Pa*s/m to 300Pa*s/m, more preferably from 120Pa*s/m to 250Pa*s/m, which has a textile fabric and a graphite-containing heat-conducting coating, wherein, based on the overall weight of the heat transfer material, the graphite is present in an amount from 5% w/w to 50%
w/w.
Surprisingly, it has been discovered that with the heat transfer material according to the invention, very good heat-conducting properties can be combined with very good acoustic properties.
The heat transfer material can even have a very simple and thin structure.
In a preferred embodiment, the amount of graphite with respect to the heat-conducting coating is more than 50% w/w, for example, from 50 to 100% w/w, preferably from 60 to 100% w/w, more preferably from 70 to 100% w/w, more preferably from 80 to 100% w/w. This is advantageous because as a result, the heat-conducting properties of the textile fabric can be significantly improved. Accordingly, a good thermal conductivity can thus be realized even with low application quantities. Low application quantities are again advantageous because as a result, the porosity and the air permeability of the textile fabric are less affected.

4 In contrast, heat-conducting coatings of textile fabrics known from the prior art usually contain a smaller quantity of graphite because the graphite layer usually contains a binder of more than 50%
w/w.
When compared to films, the use of a heat-conducting coating is advantageous because it can at least partially penetrate the textile material. Penetration into the material is once again advantageous because the heat transfer in the direction of the surface normal is improved.
In a preferred embodiment, the heat-conducting coating has thus penetrated the textile fabric at least to some extent.
When compared to perforated metal sheets, the heat-conducting coating is advantageous because, due to the faster and more uniform distribution of heat in the textile fabric, an improved bondability can be achieved.
In a preferred embodiment of the invention, the adjustment of the high portion of graphite in the heat-conducting coating is achieved in that the textile fabric comprises fibers made of a hydrophilic fiber material. Without committing to a mechanism, it is assumed that the hydrophilic fiber material has a high affinity and, related thereto, a particularly good adhesion to the graphite.
This makes it possible to keep the amount of binder in the heat-conducting coating and/or between the heat-conducting coating and the textile fabric very low.
Nevertheless, the heat-conducting coating can contain binders. Exemplary binders are polymeric binders from the group of acrylates, vinyl acrylates, vinyl acetates, ethylene vinyl acetates (EVA), acrylonitrile butadienes (NBR), styrene butadienes (SBR), acrylonitrile butadiene 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 amount 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%
w/w, for example, from 1 to 50% w/w, preferably less than 40% w/w, for example, from 1 to 40% w/w, more preferably less than 30% w/w, for example, from 1 to 30% w/w, and in particular less than 20%
w/w, for example, from 1 to 20% w/w. The use of only a small amount or a complete omission of a polymeric binder is advantageous because it improves the fire behavior of the material in case of fire, and it improves the acoustic properties.
In a preferred embodiment of the invention, the amount of graphite, relative to the overall weight of the heat transfer material, lies between 10% w/w and 50% w/w, preferably between 10% w/w and 35% w/w, more preferably between 10% w/w and 20% w/w.

5 In a further preferred embodiment of the invention, the heat-conducting coating is present in the form of a pattern on the textile fabric. In other words, some areas of the surface of the textile fabric are coated with the heat-conducting coating and other areas are not coated. In this case, the heat-conducting coating can also have penetrated the fabric at least to some extent. The design with a pattern is advantageous because the coated areas of the heat transfer material are provided with a high thermal conductivity, while the uncoated areas are particularly acoustically active, since their porosity is not reduced by the application of the heat-conducting coating. The pattern can be a geometric or irregular pattern. The degree of surface coating of the heat-conducting coating with respect to the surface of the heat transfer 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 > 0.5mm, preferably from 2.0 to 10.0 mm, particularly preferably from 4.0 to 7.0mm. Due to the continuity, a good thermal conductivity in the surface of the heat transfer material can be achieved.
In a further preferred embodiment, the pattern has at least partially discrete points, rods and/or non-continuous surfaces, preferably with a size of < 100mm2, particularly preferably from 1.0 to 50mm2, and particularly from 2.0 to 10mm2. Practical tests have shown that this leads to a rapid heat transfer through the thickness of the material, i.e., perpendicularly to the plane of the textile fabric.
The heat transfer material according to the invention is further characterized by excellent acoustic properties. The heat transfer material has a flow resistance from 60Pa*s/m to 400Pa*s/m, preferably from 100Pa*s/m to 300Pa*s/m, more preferably from 120Pa*s/m to 250Pa*s/m. In this case, the flow resistance is measured according to DIN EN 29053-A: 1993-05. By reducing or completely omitting the amount of polymeric binder, the negative influence of the heat-conducting coating on the acoustic properties of the material is reduced. A complete closure of the surface can thus be prevented, and so a sufficient porosity for acoustic effectiveness is retained. The flow resistance can be adjusted in a manner known to a person skilled in the art, for example, by a suitable selection of the fiber materials in coordination with the selected parameters during the production and coating of the textile fabric. It has been shown that a particularly good sound absorption is made possible with the flow resistances selected according to the invention. Thus, the sound absorption coefficient oi(0) of the heat transfer material according to the invention, measured in the 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 particularly more than 0.65, for example, from 0.65 to 1Ø The sound absorption coefficient is determined according to DIN EN ISO 10534-1: 2001-10 with the parameters provided in Example 2.

6 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 (PerIone), aramid, wool, cotton, silk, hemp, bamboo, kenaf, sisal, cellulose, soya, flax, glass, basalt, carbon, viscose, and their mixtures. According to the invention, the fiber material particularly preferably contains glass fibers, cellulose and/or their mixtures, in particular glass fibers and cellulose.
The textile fabric can also contain conductive fibers, e.g., metal fibers, ceramic fibers, carbon fibers, etc., to further improve the thermal conductivity.
According to the invention, cellulose fibers are particularly preferred.
Cellulose fibers refer to fibers which contain cellulose, viscose and/or fibrillar or fibrillated cellulosic components, so-called fiber pulp or pulp. Particularly preferably, the fibers consist essentially of the above-mentioned components, i.e., their portion is greater than 80% w/w.
In a preferred embodiment of the invention, the textile fabric contains cellulose fibers in an amount of at least 30% w/w, for example, from 30 to 100% w/w, and/or from 30 to 95% w/w, preferably from 50 to 100% w/w, and/or from 50 to 90% w/w, more preferably from 60 to 95%
w/w, and particularly from 65 to 85% w/w, in each case based on the overall quantity of fiber material in the textile fabric.
In a further preferred embodiment of the invention, the textile fabric contains glass fibers, preferably in a quantity from 5 to 80% w/w, more preferably from 5 to 70% w/w, even more preferably from 10 to 60% w/w, particularly from 20 to 40% w/w, in each case based on the overall quantity of fiber material in the textile fabric. With the addition of glass fibers, the textile fabric can be provided with a particularly high structural stability and low thermal shrinkage.
The textile fabric very particularly preferably contains cellulose fibers, preferably in an amount from 30 to 95% w/w, more preferably from 50 to 90% w/w, particularly from 65 to 85% w/w, and glass fibers, preferably in an amount from 5 to 70% w/w, more preferably from 10 to 50% w/w, particularly from 15 to 35% w/w, in each case based on the overall quantity of fiber material in the textile fabric.
The textile fabric could be designed as non-woven material, non-woven fabric, or paper.
According to the invention, a non-woven fabric according to DIN EN ISO 9092 is preferably used.
For producing the non-woven fabric, a non-woven material is laid dry using a carding process, a wet non-woven material process, or a spunbond process in a manner known to a person skilled in the =

7 art. The non-woven material is preferably laid using a wet non-woven material process or a carding process. As a result, a particularly high uniformity can be achieved, which is crucial for the acoustic properties. Accordingly, the non-woven fabric is preferably a wet non-woven fabric or a carded non-woven fabric. The laying of non-woven material is particularly preferably carried out using a wet non-woven material process, in particular with an inclined screen, since non-woven fabrics with particularly high uniformity can be obtained in this manner.
The fiber mixture in the wet non-woven material process could also contain fibrillar or fibrillated cellulosic components, so-called fiber pulp or pulp. These components allow for a very effective balancing of the acoustic effectiveness of the textile fabric. In a preferred embodiment, the non-woven fabric is therefore a wet non-woven fabric containing fiber pulp, particularly cellulose pulp, and/or pulp, preferably in an amount of at least 30% w/w, for example, from 30 to 100% w/w and/or from 30 to 95%
w/w, preferably from 50 to 100% w/w, and/or from 50 to 90% w/w, more preferably from 60 to 95% w/w, and particularly from 65 to 85% w/w, in each case based on the overall quantity of fiber material in the wet non-woven fabric.
Against this background, it is conceivable that the wet non-woven fabric contains two or more different fiber pulp and/or pulp types, which differ with regard to their fineness. As a result, a particularly accurate adjustment of the porosity and, associated therewith, a textile fabric with a particularly effective acoustic flow resistance is obtainable. It is also conceivable that the wet non-woven fabric contains finely ground synthetic pulps, e.g., made of viscose, polyolefin and/or aramid fibers.
The non-woven material can be solidified mechanically, chemically and/or thermally into the non-woven fabric in a known manner. The chemical bond is particularly preferably achieved by means of a polymeric binder. 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, polyvinyl ethylene vinyl chlorides, polyvinyl alcohols, polyurethanes, starch derivatives, cellulose derivatives, and their copolymers and/or mixtures. Accordingly, the non-woven fabric is preferably a chemically bonded non-woven fabric. By means of the fiber binder, a textile fabric with high strength and a good aging resistance can be obtained. The fiber binder can be applied by impregnation, spraying, or by other customary application methods.
The fiber binder can additionally contain conventional additives, such as a flame retardant, 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

8 phosphoric acid salts. For fiber bonding, this can also be introduced in the impregnation mixture via the fiber binder.
The amount of fiber binder including the additives in the heat transfer material lies preferably between 10 and 70% w/w, more preferably between 20 and 50% w/w, and particularly between 30 and 40% w/w, based on the overall weight of the heat transfer material.
The textile fabric can additionally contain corrosion inhibitors: Condensation moisture in the cooling ceiling application can particularly lead to damage to the metal elements, such as aluminum profiles, etc. The addition of a corrosion inhibitor can counteract such damage.
In addition, the textile fabric can be made to be antimicrobial by means of a biocidal additive.
During use, condensation moisture can lead to bacterial and fungal growth in the textile fabric, which can be prevented with said additive.
The basis weight of the heat transfer material lies preferably between 20 and 100g/m2, more preferably between 40 and 70g/m2, and particularly between 45 and 60g/m2, each measured according to ISO 9073-1. For a good fire behavior and good acoustic properties, a material with low basis weights, i.e., with low material usage, is recommended.
The thickness of the heat transfer material lies preferably between 0.1 and 0.5mm, more preferably between 0.15 and 0.4mm, and particularly between 0.2 and 0.3mm, each measured according to ISO 9073-2. A thin material, which simultaneously has good acoustic properties, is advantageous because it facilitates the processing, i.e., the lamination of the material in perforated metal ceilings.
The air permeability of the heat transfer material lies preferably between 100 and 3000L/m2/s, more preferably between 200 and 1000L/m2/s, and particularly between 300 and 700L/m2/s, in each case measured according to DIN EN ISO 9237 at 100Pa air pressure. These air permeabilities result in particularly good acoustic properties.
The tensile strength in at least one direction, preferably in the machine direction, of the heat transfer material is preferably from 20 to 300N/5cm, more preferably from 30 to 150N/5cm, and especially from 50 to 100N/5cm, each measured according to ISO 9073 to 3.

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9 In a preferred embodiment of the invention, the textile fabric is metallized.
The metallization can take place, for example, by a vacuum deposition process or electrochemical deposition (electroplating).
Aluminum, copper, copper alloys, stainless steel, gold and/or silver have proven to be particularly suitable metals. Particularly preferred is the use of stainless steel because it provides the textile fabric with a particularly high aging resistance. In addition, a corrosion inhibitor can be applied.
According to the invention, the heat transfer material comprises a graphite-containing heat-conducting coating. According to the invention, "graphite," in addition to graphite in the narrower sense, also refers to graphite-analogous compounds, particularly expanded graphite, graphene, and hexagonal boron nitride. In a preferred embodiment, the graphite is selected from graphite in the form of a material having multiple crystal planes and graphene, i.e., a material having only a single crystal plane. The graphite is preferably present 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 regarding workability and thermal conductivity.
Large graphite particles are advantageous for good heat conduction, but they are more difficult to process and preferably remain on the surface of the textile fabric. This results in a low penetration depth of the graphite in the heat transfer material, which leads to a reduced conductivity perpendicularly to the surface plane.
In one embodiment of the invention, the application weight of the heat-conducting coating is 1 to 50g/m2, preferably 2 to 30g/m2, particularly preferably 5 to 15g/m2.
Practical tests have shown that even with a low application weight of graphite, a distinct improvement of the thermal conductivity can be observed. At the same time, good acoustic properties can be achieved because the porosity of the material is retained.
The heat-conducting coating is applied preferably by providing the textile fabric with an aqueous graphite dispersion and the subsequent drying of said dispersion.
A binder, for example a polymeric binder, can be added to the graphite dispersion in order to improve the bonding with the textile fabric, e.g., polyacrylates, polyvinyl acrylates, polyvinyl acetates, polyethylene vinyl acetates (EVA), acrylonitrile butadienes (NBR), styrene butadienes (SBR), acrylonitrile butadiene styrenes (ABS), vinyl chlorides, ethylene vinyl chlorides, polyvinyl alcohols, polyurethanes, starch derivatives, cellulose derivatives, and their mixtures and/or copolymers.
The graphite dispersion can be mixed with further additives, e.g., defoamers, wetting agents, surfactants which facilitate processing, bases and/or acids for adjusting the pH value, flame retardants, corrosion inhibitors and/or biocides. A wetting agent is used which is preferably selected from the group

10 consisting of: Glycerol, propylene glycol, sorbitol, trihydroxystearin, phospholipids, ethylene oxide/fatty alcohol ethers, ethoxylates of propylene oxide with propylene glycol, esters of sorbitol and/or glycerol, alkyl sulfonates, alkyl sulfosuccinates, and docusates, and their mixtures.
Practical experiments have shown that an amount of the wetting agent, relative to the overall quantity of graphite dispersion, in the range from 0.1 to 5% w/w, preferably from Ito 4% w/w, particularly from 1.5 to 3.5% w/w, results in a particularly uniform and homogeneous wetting and a particularly good penetration into the material.
All common application methods for fabrics can be used, for example, impregnation, e.g., by means of foulard; printing, e.g., flat or screen printing, rotary stencil printing; kiss-coating, doctor blade, etc.; spraying; the application can be one-sided or two-sided. Particularly preferred is the coating, for example, printing, particularly by means of screen printing or rotary stencil printing. For example, the heat-conducting coating can be applied to the textile fabric as a pattern print. As a result, the heat transfer material has a high thermal conductivity locally in the printed area, while the unprinted areas are acoustically particularly active, since their porosity is not impaired by the application of the heat-conducting coating. The degree of surface coating of the heat transfer material by the heat-conducting coating in the form of a pattern ranges preferably from 1 to 100%, preferably from 10 to 60%, particularly preferably from 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 > 0.5mm, preferably from 2.0 to 10.0mm, particularly preferably from 4.0 to 7.0mm. This causes a rapid distribution of heat in the plane of the textile fabric.
In a further preferred embodiment, the printing can take place at least partially in the form of discrete points, rods and/or non-continuous surfaces, preferably with a size of < 100mm2, particularly preferably from 1.0 to 50mm2, and in particular from 2.0 to 10mm2. Practical tests have shown that this results in a rapid heat transfer through the thickness of the material, i.e., perpendicularly to the plane of the textile fabric.
The drying can be carried out with all common types of drying, e.g., contact drying with a roller dryer, circulating-air or through-air drying with a belt dryer; IR or microwave drying, etc. In order to obtain the porosity of the material and thus the good acoustic properties, through-air drying is preferred. The material can additionally be post-treated with compression rollers in order to further improve the contact of the graphite particles with each other and thus the thermal conductivity of the material.
In a preferred embodiment of the invention, the heat transfer material has an additional, preferably discontinuous adhesive mass coating. Preferably, the adhesive mass coating consists of a

11 hot-melt adhesive. The discontinuity of the adhesive mass coating is advantageous because it does not significantly affect the acoustic effectiveness of the heat transfer material.
The adhesive mass coating can be applied, for example, by sprinkling a hot-melt adhesive powder on the heat transfer material and a subsequent thermal fixation on the heat transfer material. Advantageously, the hot-melt adhesive has a melting point < 125 C.
The basis weight of the adhesive mass coating is preferably 5 to 50g/m2, more preferably 10 to 40g/m2, particularly preferably 12 to 25g/m2.
The adhesive mass coating preferably consists essentially of a thermoplastic polymer, e.g., a substantially amorphous polyester or copolyester, a polyamide or copolyamide, a polyurethane, a polyolefin, polyethylene vinyl acetate, and/or mixtures, copolymers or terpolymers thereof. In this case, "essentially" refers to a portion of at least 70% w/w, preferably more than 80% w/w, based on the overall mass of the adhesive mass coating.
The adhesive mass 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 transfer material according to the invention.
If the adhesive mass coating is applied to the textile fabric in the form of a powder, 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.) in order to further increase the thermal conductivity of the heat transfer material. The adhesive mass coating can also contain a reactive ceramic adhesive, having, for example, reactive silane groups.
The heat transfer material according to the invention is outstandingly suitable for heat transfer and simultaneous sound absorption in ceiling and/or wall elements, particularly comprising a frame, which can be fastened to the ceiling and/or wall, with a base, in which a heating and/or cooling element is arranged. In such case, the heat transfer material according to the invention is preferably arranged between the base of the frame and the heating or cooling element.
The ceiling and/or wall elements could be used in suspended, perforated and/or slotted metal ceiling and/or wall systems (also in wood or drywall ceilings, among others).
The use of the heat transfer material according to the invention in the construction of raised floors is also conceivable.

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12 In the following, the invention will be explained in more detail using several examples.
Example 1: Production of a heat transfer material according to the invention For producing a heat transfer material according to the invention, a textile fabric in the form of a wet non-woven fabric is initially produced. The overall basis weight of the wet non-woven fabric is 48g/m2. In this case, the textile fabric has a fiber mixture of 70% w/w pulp and 30% w/w glass fibers.
The fiber mixture contributes with a total of 25g/m2 to the basis weight of the textile fabric. Furthermore, the textile fabric has a fiber binder made of polyacrylate binder and flame retardant with a basis weight contribution of 23g/m2.
For producing the heat-conducting coating, a commercially available graphite dispersion with an average particle diameter of 2.5 micrometers and a solids content of 18%
w/w is used. The application is carried out by means of rotary stencil printing and subsequent drying in the through-air oven. A rectangular diamond pattern is selected as the stencil. The average width of the printed lines on the wet non-woven fabric is 5.0mm, the heat-conducting coating coats 52% of the surface. The portion of graphite in the heat-conduction coating, measured according to Example 4, is 80% w/w, which corresponds to a portion of 14% w/w, based on the overall weight of the heat transfer material.
The resulting heat transfer material has an overall weight of 57g/m2, a thickness of 0.23mm, a tensile strength in machine direction of 65N/5cm, an air permeability of 550L/m2/s at 100Pa, and a flow resistance of 190Pa*s/m.
Example 2: Determination of the sound absorption coefficient of the heat transfer material For tests in the impedance tube, the heat transfer material is provided with an adhesive mass coating. The adhesive mass consists of epsilon-polycaprolactone, which is powdered as a ground powder with an average particle size of 150 micrometers onto the heat transfer material and sintered in the oven. In this case, the application quantity is 15g/m2.
The heat transfer material provided with the adhesive mass coating is subsequently ironed onto perforated, painted sheet steel, having a thickness of 0.5mm, a perforation surface portion of 15%, and a perforation diameter of 2.3mm. The sound absorption coefficient is determined on the composite material and a(0) is specified at a frequency of 1600Hz.
A sound absorption coefficient of a(0) = 0.7 at 1600Hz is determined.

13 Example 3: Determination of the thermal conductivity of the heat transfer material The thermal conductivity of the heat transfer material, when compared to the textile fabric without a heat-conducting coating, is examined. The measurements are carried out by means of the plate method according to DIN 52612 on 6-fold stacked test specimens and according to the hot-disk method as a single layer according to ISO 22007-2.2:2008, Part 2.
Textile Heat transfer material Method thermal conductivity Unit fabric Plate method W/(K*m) 0.06 0.08 Hot disk W/(K*m) 0.06 0.09 Example 4: Qualitative and quantitative determination of the graphite A qualitative identification of the graphite is carried out by means of X-ray angle distribution (XRD) in accordance with DIN EN 13925-2 2003-07. For this purpose, X-ray diffractograms of the heat transfer material are recorded with CoKa radiation at 40kV and 35mA in the angular range of 5 to 60 (2 theta). An conclusive identification is possible via the sharp reflexes at 30.78 (3.37A); 49.69 (2.13A);
52.19 (2.04A); 64.37 (1.68A); 93.21 (1.23A). The amount of graphite in the heat transfer material or the heat-conducting coating can be quantitatively determined by means of thermogravimetric analysis (TGA) according to DIN EN ISO 11358 2014-10. The sample is initially heated in an inert nitrogen atmosphere to 1000 C and cooled again to 300 C. The sample is subsequently reheated under oxygen to 1000 C. This last stage of combustion results in the combustion of the graphite and (if present) the carbon black. During this process, carbon black combusts in a temperature range from 380 C to 700 C
and graphite at temperatures > 700 C. If the combustion of the carbon black is not completely separated from that of the graphite, the derivation of the thermogravimetric curve, which then shows a reversal point at 700 C, is used to determine the temperature ranges to be evaluated.

Claims

Claims:

1. Heat transfer material with a flow resistance from 60Pa*s/m to 400Pa*s/mõ having a textile fabric and a graphite-containing heat-conducting coating, wherein the graphite is present in an amount from 5% w/w to 50% w/w, based on the overall weight of the heat transfer material.

2. Heat transfer material according to claim 1, wherein the flow resistance is from 100Pa*s/m to 300Pa*s/m.

3. Heat transfer material according to claim 1, wherein the flow resistance is from 120Pes/m to 250Pa*s/m.

4. Heat transfer material according to any one of claims 1-3, wherein the amount of graphite in relation to the heat-conducting coating is more than 50% w/w.

5. Heat transfer material according to claim 4, wherein the amount of graphite in relation to the heat-conducting coating is from 60 to 100% w/w.

6. Heat transfer material according to claim 4, wherein the amount of graphite in relation to the heat-conducting coating is from 70 to 100% w/w.

7. Heat transfer material according to claim 4, wherein the amount of graphite in relation to the heat-conducting coating is from 80 to 100% w/w.

8. Heat transfer material according to any one of claims 1-7, wherein an amount of polymeric binder in the heat-conducting coating is less than 40% w/w in relation to the heat-conducting coating.

9. Heat transfer material according to any one of claims 1-8, wherein the amount of polymeric binder between the heat-conducting coating and the textile fabric is less than 40%
w/w in relation to the heat-conducting coating.

10. Heat transfer material according to any one of claims 1-9, wherein the textile fabric comprises fibers made of a hydrophilic fiber material.

11. Heat transfer material according to any one of claims 1-10, wherein the heat conducting coating is present in the form of a pattern on the textile fabric.

Date Recue/Date Received 2021-03-05

12. Heat transfer material according to claim 11, wherein the pattern has at least partially continuous lines.

13. Heat transfer material according to any one of claims 1-12, wherein the application weight of the heat-conducting coating is 1 to 50g/m2.

14. Heat transfer material according to any one of claims 1-13, wherein the graphite is present in particle form with an average particle size of 0.5 to 10pm.

15. Heat transfer material according to any one of claims 1-14, wherein a sound absorption coefficient is more than 0.55, measured in an impedance tube at 1600Hz.

16. Heat transfer material according to any one of claims 1-15, wherein the textile fabric contains cellulose fibers in an amount of at least 30% w/w, based on the overall quantity of fiber material in the textile fabric.

17. Heat transfer material according to claim 16, wherein the cellulose fibers are in an amount from 50 to 100% w/w, based on the overall quantity of fiber material in the textile fabric.

18. Heat transfer material according to claim 16, wherein the cellulose fibers are in an amount from 50 to 90% w/w, based on the overall quantity of fiber material in the textile fabric.

19. Heat transfer material according to claim 16, wherein the cellulose fibers are in an amount from 60 to 95% w/w, based on the overall quantity of fiber material in the textile fabric.

20. Heat transfer material according to any one of claims 1-15, wherein the textile fabric contains glass fibers in an amount from 5 to 80% w/w, based on the overall quantity of fiber material in the textile fabric.

21. Heat transfer material according to claim 20, wherein the glass fibers are in an amount from 5 to 70% w/w, based on the overall quantity of fiber material in the textile fabric.

22. Heat transfer material according to claim 20, wherein the glass fibers are in an amount from 10 to 60% w/w, based on the overall quantity of fiber material in the textile fabric.

23. Heat transfer material according to claim 20, wherein the glass fibers are in an amount from 20 to 40% w/w, based on the overall quantity of fiber material in the textile fabric.
Date Recue/Date Received 2021-03-05

24. Heat transfer material according to any one of claims 1-23, wherein the textile fabric is a wet non-woven fabric or a carded non-woven fabric.

25. Heat transfer material according to any one of claims 1-24, having a basis weight of 20 to 100g/m2.

26. Heat transfer material according to any one of claims 1-25, having a thickness of 0.1 to 0.5mm.

27. Heat transfer material according to any one of claims 1-26, having an air permeability of 100 to 3000L/m2/s.

28. Heat transfer material according to any one of claims 1-27, wherein the heat transfer material contains a hot-melt adhesive.

29. Heat transfer material according to claim 28, wherein the hot-melt adhesive is in the form of a discontinuous adhesive mass coating.

30. Heat transfer material of any one of claims 1-29, wherein the graphite is present in an amount from 10 to 50% w/w, based on the overall weight of the heat transfer material.

31. Heat transfer material of any one of claims 1-29, wherein the graphite is present in an amount from 10 to 35% w/w, based on the overall weight of the heat transfer material.

32. Heat transfer material of any one of claims 1-29, wherein the graphite is present in an amount from 10 to 20% w/w, based on the overall weight of the heat transfer material.

33. Use of a heat transfer material according to any one of claims 1-32 for heat transfer and simultaneous sound absorption in ceiling elements, or wall elements, or both ceiling elements and wall elements.

34. Use according to claim 33, wherein each of the ceiling elements, or the wall elements, or both ceiling and wall elements comprises a frame fastenable to a ceiling or a wall, the frame having a base in which a heating element or a cooling element is arranged.