AT527130B1 - construction film - Google Patents

Abstract

The invention relates to a construction film (1) comprising a multi-layer composite material (2) with a reinforcement layer (3) which is formed by a fiber structure made of a fiber material, and a membrane layer (4), wherein the membrane layer (4) is formed by at least fluoropolymer and the reinforcement layer (3) is formed by a fiber structure made of a fiber material. The membrane layer (4) has a basis weight of between 1 g/m² and 40 g/m².

Description

Description

[0001] The invention relates to a construction film, in particular a roofing membrane, comprising a multi-layer composite material with a reinforcement layer, which is formed by a fiber structure, in particular a woven or knitted fabric, made of a fiber material, and a membrane layer.

[0002] The invention further relates to a method for producing a construction film, in particular a roofing membrane, by forming a multi-layer composite material with a reinforcement layer and a membrane layer, wherein a fiber structure, in particular a woven or knitted fabric, made of a fiber material is used for the reinforcement layer.

[0003] Underlayment membranes are known from the state of the art in a wide variety of designs for arrangement under a roof covering or on a building facade. The state of the art describes waterproof underlayment membranes that have a two-layer structure with a carrier layer made of a fleece and a sealing layer based on TPU. Examples of this are EP 2 592 196 B1, DE 20 2009 007 315 U1, DE 20 2010 000 934 U1, the latter also describing a three-layer structure with sealing layers arranged on both sides of the carrier layer.

[0004] Roofing membranes with more than three layers are known, for example, from DE 10 2017 003 364 A1, which describes an underroof membrane with at least one outer nonwoven layer, at least one inner nonwoven layer, at least one microporous membrane layer based on at least one polyolefinic plastic, and at least one further microporous membrane layer based on a polyolefinic plastic between the nonwoven layers, which is separated from the membrane layer by a separating layer.

[0005] From EP 0 708 212 A1, an underlayment is known which has a three-layer structure comprising two water and water vapor permeable, water and water vapor resistant nonwoven layers and a film-like, water vapor permeable, water impermeable, water and/or water vapor absorbing and water and water vapor resistant barrier layer embedded between and connected to the nonwoven layers.

[0006] From DE 10 2015 012 015 A1 a multilayer composite film for the construction sector is known, with at least one water and water vapor permeable carrier layer and a waterproof and water vapor permeable functional layer, wherein the material of the functional layer is a TPU of the carbonate type.

[0007] The prior art therefore predominantly describes the use of fleeces. However, the use of fabrics is also known. For example, DE 1 659 300 A1 describes a flame-retardant plastic composite sheet suitable for bonding for roof covering, consisting of a flame-retardant plastic film and a solidifying and also flame-retardant or non-flammable fabric, knitted fabric or fleece, whereby the flame-retardant or non-flammable fabric, knitted fabric or fleece is fixed to the underside intended for bonding in such a way that it is not covered by the plastic. On the top side, another flame-retardant and particularly weather-resistant film, preferably made of polyvinyl fluoride or polytetrafluoroethylene, can be arranged on the flame-retardant plastic film. This structure ensures that the connection to the underside roof and the top side roof film, which is made using hot bitumen or adhesive, receives an adhesion-promoting component.

[0008] WO 96/37667 A1 describes an underlayment for installation in roofs to prevent heat convection losses and to improve the indoor climate, which has at least one non-porous, waterproof, water vapor permeable functional layer that contains polymers based on copolyetherester and/or copolyetheramide. A water vapor permeable support layer can be applied to at least one side of the functional layer, which is a fleece, felt, knitted fabric, foam and/or fabric, preferably with thread or mesh reinforcement.

[0009] From DE 103 31 177 A1 a composite material consisting of a construction film and a textile fabric containing an electrically conductive structure is known.

[0010] The present invention is based on the object of creating an improved, flame-retardant construction film which can also be used without the use of bitumen as a connection to the roof substructure or facade substructure.

[0011] The object is achieved with the construction film mentioned at the outset, in which the membrane layer is formed by at least one polymer selected from a group comprising fluoropolymers, in particular polytetrafluoroethylene, and has a basis weight between 1 g/m? and 40 g/m?.

[0012] Furthermore, the object is achieved by the method mentioned at the outset, according to which at least one polymer selected from a group comprising fluoropolymers, in particular polytetrafluoroethylene, with a basis weight between 1 g/m? and 40 g/m? is used as the membrane layer.

[0013] The advantage here is that the membrane layer can be better protected by the reinforcement layer, the construction film can also be designed to be tread-resistant, and that due to the materials of the membrane layer, the construction film can be designed with improved water impermeability and vapour permeability.

[0014] According to a preferred embodiment of the invention, the membrane layer can be arranged between the reinforcement layer and another layer. The advantage here is that the membrane layer can be better protected against mechanical stress by integrating it on both sides. The reinforcement layer, which is usually on the outside when the construction film is installed, can make the construction film non-slip, so that the construction film in the roofing membrane version can also be walked on without being damaged. The combination of a reinforcement with the other layer made of a fiber material with the membrane layer arranged in between improves the usability of the polymer materials that are highly effective in terms of water impermeability and vapor permeability, whereby the layer thickness of the membrane layer can be kept low due to the protective layers on both sides.

[0015] According to one embodiment of the invention, it can be provided that the fiber material of the fiber structure is formed exclusively by inorganic fibers, in particular by glass fibers, basalt fibers, carbon fibers or mixtures thereof or with them. By using exclusively inorganic fibers, the reinforcement layer can form a fire barrier. This can be further strengthened if a fluoropolymer, in particular polytetrafluoroethylene, is used as the membrane layer. The construction film can therefore have a fire-retardant effect and thus counteract the spread of fire.

[0016] According to a further embodiment of the invention, it can be provided that the fiber structure, in particular the woven or knitted fabric, has a basis weight between 50 g/m2 and 250 g/m2, whereby the above effects can be further improved, since in particular a (very) dense fiber structure can be used.

[0017] Also to improve the above-mentioned effects, according to an embodiment variant of the invention, it can be provided that the further layer is designed like the reinforcement layer.

[0018] An improvement in the membrane properties can be achieved if, according to an embodiment of the invention, the polymer of the membrane layer is uniaxially or biaxially stretched. By stretching the membrane polymer, a microporous layer can be produced which is waterproof and windproof, but which is nevertheless permeable to water vapor. These properties of the membrane layer are particularly pronounced if the fluoropolymer is a polytetrafluoroethylene.

[0019] According to another embodiment of the invention, it can be provided that the membrane layer lies directly on the reinforcement layer and the further layer and thus

A ches AT 527 130 B1 2024-11-15

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This can simplify the production of the membrane layer, as the application of an additional adhesion promoter between the layers of the construction film can be omitted.

[0020] As an alternative to this embodiment variant, according to another embodiment variant of the invention, it can be provided that the membrane layer is connected to the reinforcement layer and the further layer by means of an adhesion promoter.

[0021] According to a further embodiment of the invention, it can be provided that the adhesion promoter is arranged in less than 100% of the contact surface of the membrane layer on the reinforcement layer and/or that the adhesion promoter is arranged in less than 100% of the contact surface of the membrane layer on the further layer. This enables better mobility of the membrane layer in the construction film, whereby tensions in the layer structure, e.g. as a result of temperature fluctuations, and their effect on the permeation properties of the construction film can be better avoided.

[0022] According to another embodiment of the invention, it can be provided that the additional layer is designed to provide electromagnetic shielding. This means that the construction film can not only fulfill its own functions, but can also, for example, introduce the additional effect of electromagnetic shielding into the roof structure or the facade structure under photovoltaic systems, which means that no further measures are required for this.

[0023] According to an embodiment variant of the invention, it can be provided that the additional layer has a higher surface weight than the reinforcement layer. The construction film can thus be better protected against mechanical damage as a result of different thermal expansions of the substrate and the construction film.

[0024] According to a further embodiment of the invention, it can be provided that the further layer is formed from different fibers to the fibers of the reinforcement layer, whereby, for example, the rear layer of the construction film can be given different strength values or different properties than the front layer. The construction film can thus be better adapted to a wide variety of applications.

[0025] To further improve the properties of the construction film, according to one embodiment of the invention, it can be provided that the membrane layer is made up of multiple layers. This makes it possible, for example, to achieve the properties "windproof", "waterproof" and "vapor-permeable" with different polymers, so that according to one embodiment, it can be provided that the multi-layer membrane layer has at least two layers, with the two layers each having a polymer and with the polymers being different from one another. With this embodiment, the nail strength or nail tightness of the construction film can also be improved, for example by one polymer being a "self-sealing" polymer that seals against the nail shaft after a nail has penetrated. For example, in this embodiment, one layer can consist of a PTFE and the other layer of a TPU, or the layers can comprise these polymers.

[0026] For a better understanding of the invention, it is explained in more detail with reference to the following figure.

[0027] It shows in a simplified, schematic representation: [0028] Fig. 1 A section of a construction film in side view; [0029] Fig. 2 A section of a variant of the construction film in side view.

[0030] To begin with, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or identical component designations, whereby the disclosures contained in the entire description can be transferred analogously to identical parts with identical reference symbols or identical component designations. The position information chosen in the description, such as top, bottom, side, etc., also refers to the figure directly described and shown, and these position information must be transferred analogously to the new position in the event of a change in position.

[0031] It should be noted at this point that references to standards are to be understood as meaning the respective standards in the version valid on the filing date of this patent application or of the patent application establishing priority, unless otherwise stated.

[0032] In Fig. 1, a section of a construction film 1, in particular an underlay membrane (also referred to as an underroof membrane or facade membrane), is shown in side view.

[0033] In addition to its design as a construction film 1 in the form of an underlayment, it can also be used as a fire barrier or as a shield against electrosmog, etc.

[0034] The construction film 1 in the "underlayment" version serves as a second water-draining layer under the roof covering, e.g. with tiles, to protect against drift, capillary, stagnant and condensate water or dirt. The construction film 1 can also be used as a facade film for a wind and rain-tight facade construction, for example in a ventilated facade construction with facade cladding. The construction film 1 can also be used underneath a photovoltaic module or a photovoltaic tile, etc., as a shielding film against electrosmog.

[0035] In the roof sheeting variant, the construction film 1 can rest directly on a roof sheathing and in particular be attached to it. The roof sheathing can be formed, for example, by (rough-sawn) wooden boards. On the outside, battens of a counter batten can be attached. The counter batten supports the battens for the roof tiles. The battens can be connected to the roof substructure with fastening means, for example nails. To do this, the fastening means penetrate the construction film 1.

[0036] Even in the facade sheet variant, the construction film 1 can be in direct contact with a corresponding substructure, e.g. thermal insulation, and covered from the outside with a facade cladding. To install the facade cladding, battens, possibly with counter battens, can be used, the fastening means of which penetrate the construction film 1.

[0037] Since such roof and facade structures are known per se, reference is made to the relevant state of the art for further details.

[0038] Apart from such structures of facades and roofs, the construction film 1 can also be used in other structures on the exterior of buildings.

[0039] In the preferred embodiment of the construction film 1, it is used on an outside of a building, such as, for example, in the roof structure or in the facade structure.

[0040] All of the following statements regarding the construction film 1 in the form of an under-roof membrane or underlay membrane can therefore also be applied to the facade membrane or the other stated uses of the construction film 1, unless explicitly stated otherwise.

[0041] In the preferred embodiment, the construction film 1 is designed to be waterproof and permeable to vapour diffusion.

[0042] Waterproof means that the construction film 1 meets the requirements of EN 13859 Part 1/2.

[0043] Vapour permeable means that the water vapour permeability Sd according to EN 13859 Part 1/2 is between 0.01 m, in particular 0.02 m, and 0.5 m.

[0044] The construction film 1 can have a width of at least 0.3 m, in particular between 0.5 m and 2 m. The width is measured at an angle of 90 ° to the winding direction of the construction film 1 on a roll. However, this information is only intended to explain the term "web". It has no limiting character for the invention.

[0045] The construction film 1 comprises a multi-layer composite material 2 or consists thereof. The multi-layer composite material 2 in the embodiment according to Fig. 1 comprises three layers, namely

a reinforcement layer 3, a membrane layer 4 and a further layer 5, or consists of these. In the simplest version of the construction film 1, this only consists of the reinforcement layer 3 and the membrane layer 4, and is therefore designed in two layers.

[0046] The reinforcement layer 3 is arranged on the outside, i.e. it faces the weather side. The further layer 5, if present, is arranged on the inside, i.e. it is arranged on the building side. The membrane layer 4 is arranged between the reinforcement layer 3 and the further layer 5 or below the reinforcement layer 3.

[0047] In the embodiment of the construction film 1 with a further layer 5 as a roof underlay, the further layer 5 can rest (directly) on the roof sheathing.

[0048] The membrane layer 4 provides watertightness and water vapor permeability.

[0049] The reinforcement layer 3 is formed by a fiber structure made of fibers. The fiber structure is preferably a woven or knitted fabric or a knit made of fibers.

[0050] The term “fiber” is used in this description synonymously with thread, so that the term “fiber” includes both fibers per se and threads.

[0051] The fabric can be made, for example, with a plain weave, twill weave or satin weave. A plain weave is preferably used.

[0052] The fabric or the reinforcement layer 3 can have a basis weight of between 10 g/m2 and 1000 g/m2, in particular between 50 g/m2 and 250 g/m2. However, for the reasons stated above, a fabric or reinforcement layer 3 with a basis weight of between 100 g/m2 and 250 g/m2, in particular between 150 g/m2 and 220 g/m2, is preferably used. This allows a closed layer to be created which not only enables improved impact resistance of the construction film 1, but also allows a uniform material connection to the membrane layer 4 to be achieved. In addition, properties of the first construction film 1, such as thermal expansion or creep tendency, can be influenced.

[0053] However, it is also possible to use an open-mesh or more open-mesh fabric with a basis weight between 10 g/m? and 90 g/m*.

[0054] The reinforcement layer 3 can be designed as a single layer or as a multi-layer. In the multi-layer design, at least some of the layers can be different from the at least one other layer, for example, they can consist of different fibers or have a different basis weight.

[0055] It is also possible that rubberized fibers are used in the fabric or in the fiber structure or the reinforcement layer 3.

[0056] The fabric or the reinforcement layer 3 is formed with inorganic fibers. In particular, these fibers can be selected from a group comprising or consisting of glass fibers, carbon fibers, mineral fibers, such as basalt fibers, or mixtures thereof or thereof or therewith. The proportion of inorganic fibers in the fiber structure, for example the fabric, can be at least 80% by weight, in particular at least 90% by weight. Preferably, the fabric or the reinforcement layer 3 consists exclusively of inorganic fibers, in particular exclusively of glass fibers.

[0057] In the event that the reinforcement layer 3 or the fiber structure does not consist exclusively of inorganic fibers, it can comprise, for example, aramid fibers or natural fibers, such as hemp, sisal, and combinations thereof. With regard to the desired fire-retardant effect of the construction film 1, however, fibers should be selected that also have a fire-retardant effect or that have a fire-retardant finish. If necessary, the reinforcement layer 3 can also consist exclusively of organic fibers or organic polymer fibers with a fire-retardant effect. In the preferred embodiment of the construction film 1, however, the reinforcement layer 3 comprises inorganic fibers or consists of them.

[0058] The woven or knitted fabric or the reinforcement layer 3 may optionally (for example if not or not exclusively inorganic fibres are used) also

be equipped with special treatments such as UV stabilization, flame retardancy, etc.

[0059] The further layer 5 can be designed in the same way as the reinforcement layer 3. The further layer 5 can form a further reinforcement layer. The above statements on the reinforcement layer 3 can therefore be transferred to the further layer 5. Preferably, the further layer 5 also comprises a fiber structure made of fibers, in particular a woven or knitted fabric or knit, in particular with or made of inorganic fibers, or consists thereof.

[0060] The further layer 5 can also be designed differently to the reinforcement layer 3. For example, the further layer 5 can be designed to provide electromagnetic shielding. This can be achieved, for example, if electrically conductive materials such as metal fibers, e.g. made of copper or aluminum, and/or carbon fibers are added to the fiber structure, in particular the woven or knitted fabric of the further layer 5. The further layer 5 can also be designed with a metal foil, a metal mesh or metal-deposited fibers. The metal foil or the metal mesh can be arranged on the back of the further layer 5 or between the membrane layer 4 and the further layer 5 or within the further layer 5 if it is designed in multiple layers, for example.

[0061] The further layer 5 can also have a different basis weight to that of the reinforcement layer 3, wherein the basis weight can be selected from the ranges mentioned above. The further layer 5 can have a lower basis weight than the reinforcement layer 3. Preferably, however, the further layer 5 has a higher basis weight than the reinforcement layer 3. The basis weights of the further layer 5 and the reinforcement layer 3 preferably differ by a maximum of 20%, in particular a maximum of 10%.

[0062] According to another embodiment, it can also be provided that the further layer 5 is formed from different fibers to the fibers of the reinforcement layer 3. For example, the reinforcement layer 3 can be formed from glass fibers and the further layer 5 from basalt fibers. Other combinations of fibers, in particular inorganic fibers, preferably from the group mentioned above, are also possible.

[0063] The membrane layer 4 comprises or consists of at least one polymer.

[0064] A polymer within the meaning of the invention is a material made from several similar building blocks, the so-called monomers. In particular, the polymer is exclusively a synthetic polymer.

[0065] The polymer is selected from a group comprising or consisting of fluoropolymers, in particular polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (ePTFE), and thermoplastic polyurethanes (TPU). The membrane layer 4 particularly preferably consists of PTFE and/or ePTFE.

[0066] The (e)PTFE may have pores with a pore size between 0.2 +/- 0.1 µm and 0.6 +/- 0.2 µm.

[0067] However, the fluoropolymer can also be a perfluoropolymer, e.g. a perfluoroalkoxy polymer (PFA), a polymer with polyhexafluoropropylene (HFP), a perfluoro(ethylene-propylene) copolymer (FEP), an ethylene-tetrafluoroethylene copolymer (ETFE), a polyvinylidene fluoride (PVDF), a polychlorotrifluoroethylene (PCTFE), a copolymer with perfluoropropylene vinyl ether (PPVE), e.g. a PTFE modified with PPVE, a perfluoromethyl vinyl ether (MFA) and a mixture thereof or with PTFE.

[0068] According to a further embodiment of the construction film 1, it can be provided that the polymer of the membrane layer 4, in particular the PTFE, is uniaxially or biaxially stretched (stretched). A stretching ratio can be selected from a range of v1: 4 to 1:15, in particular 1: 4 to 1:12. In the case of biaxially stretched polymers, it can be provided that the stretching in the film direction or in the web direction is different, in particular is greater, than in the orthogonal direction (the width of the film or the web). The uniaxial stretching preferably takes place in the film direction, i.e. the length of the film (the winding direction).

tion).

[0069] The stretching can be carried out at a temperature between 130 °C and 400 °C, in particular between 150 °C and 290 °C. The stretching is preferably carried out in a continuous process, i.e. with the film or web running.

[0070] In addition, the stretching can be carried out using known stretching devices. Reference is made to the relevant state of the art.

[0071] In the embodiment shown in Fig. 1, the membrane layer 4 lies directly on the reinforcement layer 3 and the further layer 5 and is connected to it. This can be achieved, for example, by pressing the reinforcement layer 3, the membrane layer 4 and the further layer 5 together. For this embodiment, it is advantageous if the membrane layer 4 has a surface weight of between 3 g/m* and 30 g/m?.

[0072] In general, the membrane layer 4 has a basis weight between 1 g/m* and 40 g/m®, in particular between 2.5 g/m* and 20 g/m®?.

[0073] The membrane layer 4 can have a layer thickness between 5 µm and 60 µm.

[0074] Alternatively or additionally, however, it is also possible for the membrane layer 4 to be connected to the reinforcement layer 3 and/or the further layer 5 by means of an adhesion promoter. A (reactive) polyurethane-based hot melt adhesive can be used as an adhesion promoter, for example. Such adhesion promoters are known from the relevant prior art. In this embodiment of the construction film 1, it is advantageous if the adhesion promoter is arranged in less than 100%, in particular less than 70%, preferably less than 50%, of the contact surface of the membrane layer 4 on the reinforcement layer 3 and/or that the adhesion promoter is arranged in less than 100%, in particular less than 70%, preferably less than 50%, of the contact surface of the membrane layer 4 on the further layer 5. The adhesion promoter can be arranged in at least 10%, in particular at least 15%, preferably at least 20%, of the contact surface of the membrane layer 4 on the reinforcement layer 3 and/or in at least 10%, in particular at least 15%, preferably at least 20%, of the contact surface of the membrane layer 4 on the further layer 5. The adhesion promoter can be applied in powder form or in bead form or band form.

[0075] The bonding can be carried out, for example, in a point-like or strip-like manner. The connection points can be arranged at a distance from one another that is selected from a range of 1 mm to 10 mm. The distance is the shortest distance between two immediately adjacent connection points. The connection points can be arranged in the form of a network (square, rectangle, diamond, etc.).

[0076] Fig. 2 shows a section of a further and possibly independent embodiment variant of the construction film 1. This again comprises the reinforcement layer 3, the membrane layer 4 and the further layer 5. To avoid repetition, reference is made to the above explanations for these layers.

[0077] In contrast to the embodiment of the construction film 1 according to Fig. 1, in this embodiment the membrane layer 4 is multi-layered or multi-ply. In the embodiment shown in concrete terms, the membrane layer 4 has a first partial layer 6 and a second partial layer 7. However, the membrane layer 4 can also have more than these two partial layers 6, 7, for example three or four.

[0078] Each of the partial layers 6, 7 preferably extends over the entire surface of the construction film 1 (viewed from above). The partial layers 6, 7 are therefore not only arranged in discrete areas, although this is possible within the scope of the invention. For example, the membrane layer 4 can consist of several strip-shaped partial layers 6, 7, which are arranged next to one another in a common plane, in particular alternating.

[0079] The partial layers 6, 7 can be made of the same material, for example PTFE. It can also be provided that the partial layers 6, 7 of the multilayer membrane layer 4 each have or consist of at least one polymer, wherein the polymers

are different from each other. For example, one of the partial layers 6, 7 can consist of a PTFE and the other of the partial layers 6, 7 of a TPU in order to give the construction film 1 improved nail-tightness. Nail-tightness means that a nail penetrating the construction film 1 does not cause water to pass through the construction film 1 from the outside to the inside.

[0080] The partial layers 6, 7 can all have the same layer thickness. However, they can also have a different layer thickness from one another, as shown in Fig. 2. For example, the partial layer 7 facing the further layer 5 can have a greater layer thickness than the partial layer 6 facing the reinforcement layer 3.

[0081] The construction film 1 can be produced by forming a multi-layer composite material. For this purpose, at least the reinforcement layer 3, the membrane layer 4 and optionally the further layer 5 are provided, arranged on top of one another and connected to one another. The production preferably takes place continuously using known technologies for producing multi-layer films. For further details, reference is therefore made to the relevant prior art.

[0082] To evaluate the construction film 1, the following examples were produced.

EXAMPLE 1:

[0083] A construction film 1 was produced which had the following structure: Glass fiber fabric as reinforcement layer 3, 75 g/m? Adhesive layer: Hot melt adhesive Membrane layer 3: PTFE, 3 g/m*

Adhesive layer: Hotmelt adhesive Glass fiber fabric as additional layer 5: 75 g/m*

EXAMPLE 2:

[0084] A construction film 1 was produced which had the following structure: Glass fiber fabric as reinforcement layer 3: 150 g/m? Membrane layer 3: PTFE, 20 g/m?

Glass fiber fabric as additional layer 5: 100 g/m?

EXAMPLE 3:

[0085] A construction film 1 was produced which had the following structure: Glass fiber fabric as reinforcement layer 3: 200 g/m? Adhesive layer: Hot melt adhesive Membrane layer 3: PTFE, 9.53 g/m?

Adhesive layer: Hotmelt adhesive Glass fiber fabric as additional layer 5: 200 g/m*

EXAMPLE 4:

[0086] A construction film 1 was produced which had the following structure: Glass fiber fabric as reinforcement layer 3: 150 g/m? Adhesive layer: Hot melt adhesive Membrane layer 3: PTFE, 30 g/m?

Adhesive layer: Hotmelt adhesive Basalt fiber fabric as additional layer 5: 200 g/m*

[0087] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure of the construction film 1, this or its components are not shown to scale.

REFERENCE SYMBOL LIST

1 construction foil

2 Multilayer composite material 3 Strength carrier layer

4 membrane layers

5 layer

6 sub-layers

7 sub-layers

Claims (19)

patent claims 1. Construction film (1) comprising a multi-layer composite material (2) with a reinforcement layer (3) which is formed by a fiber structure, in particular a woven or knitted fabric, made of a fiber material, and a membrane layer (4), characterized in that the membrane layer (4) is formed by at least one fluoropolymer, in particular polytetrafluoroethylene, and has a basis weight between 1 g/m? and 40 g/m*. 2, Construction film according to claim 1, characterized in that the membrane layer is arranged between the reinforcement layer (3) and a further layer (5). 3. Construction film (1) according to claim 1 or 2, characterized in that the fiber material of the fiber structure is formed exclusively by inorganic fibers, in particular by glass fibers, basalt fibers, carbon fibers or mixtures thereof. 4. Construction film (1) according to one of claims 1 to 3, characterized in that the fiber structure has a basis weight between 50 g/m* and 250 g/m?. 5. Construction film (1) according to one of claims 2 to 4, characterized in that the further layer (5) is designed according to claim 3 or 4. 6. Construction film (1) according to one of claims 1 to 5, characterized in that the polymer of the membrane layer (4) is uniaxially or biaxially stretched. 7. Construction film (1) according to one of claims 1 to 6, characterized in that the membrane layer (4) lies directly on the reinforcement layer (3) and is connected thereto. 8. Construction film (1) according to one of claims 2 to 7, characterized in that the membrane layer (4) lies directly on the further layer (4) and is connected thereto. 9. Construction film (1) according to one of claims 1 to 8, characterized in that the membrane layer (4) is connected to the reinforcement layer (3) by means of an adhesion promoter. 10. Construction film (1) according to one of claims 2 to 9, characterized in that the membrane layer (4) is connected to the further layer (5) by means of an adhesion promoter. 11. Construction film (1) according to claim 9 or 10, characterized in that the adhesion promoter is arranged in less than 100% of the contact surface of the membrane layer (4) on the reinforcement layer (3). 12. Construction film (1) according to claim 10 or 11, characterized in that the adhesion promoter is arranged in less than 100% of the contact surface of the membrane layer (4) on the further layer (5). 13. Construction film (1) according to one of claims 1 to 12, characterized in that the further layer (5) is designed to provide electromagnetic shielding, for which purpose the further layer (5) contains electrically conductive materials, in particular metal fibers, or is designed with a metal foil or a metal grid or is metal-coated. 14. Construction film (1) according to one of claims 2 to 13, characterized in that the further layer (5) has a higher surface weight than the reinforcement layer (3). 15. Construction film (1) according to one of claims 2 to 14, characterized in that the further layer (5) is formed from different fibers to the fibers of the reinforcement layer (3). 16. Construction film (1) according to one of claims 1 to 15, characterized in that the membrane layer (4) is multi-layered. 17. Construction film (1) according to claim 16, characterized in that the multilayer membrane layer (4) has at least two partial layers (6, 7), wherein the two partial layers (6, 7) each have a polymer and wherein the polymers are different from one another. 18. Method for producing a construction film (1) by forming a multi-layer composite material (2) with a reinforcement layer (3) and a membrane layer (4), wherein a fiber structure, in particular a woven or knitted fabric, made of a fiber material is used for the reinforcement layer (3), characterized in that at least one fluoropolymer, in particular polytetrafluoroethylene, with a basis weight between 1 g/m" and 40 g/m* is used as the membrane layer (4). 19. Method according to claim 18, characterized in that the membrane layer (4) is arranged between the reinforcement layer (3) and a further layer (5) and is connected to the reinforcement layer (3) and the further layer (5). 1 sheet of drawings