Vapour barrier

Abstract

The invention relates to a flat web (1) for the construction sector comprising at least two layers, one layer (2) being moisture-variable and comprising a polyamide material, and the other layer (3) being substantially moisture-independent. According to the invention, the polyamide material is a polyamide of polyamide type 4.6.

Description

[0001] Vapor barrier

[0002] The invention relates to a moisture-variable vapor barrier and its use for sealing buildings.

[0003] Vapor barriers are typically used in building roof structures to control the diffusion of water vapor into the structure. They are designed to prevent moisture from penetrating insulation layers while simultaneously allowing buildings to dry out. They also act as an airtight layer.

[0004] A measure of the resistance a building component layer offers to water vapor diffusion is the sd value, which is defined as the water vapor diffusion-equivalent air layer thickness and represents the product of the water vapor diffusion resistance factor and the layer thickness. The sd value is measured according to DIN EN ISO 12572:2016. The higher the sd value, the greater the resistance. An sd value of 2 m means that the layer offers the same resistance to water vapor diffusion as a 2 m thick layer of air. Water vapor diffusion through a layer with an sd value of 10 m is therefore slower than through a layer with an sd value of 2 m.

[0005] Various moisture-variable vapor barriers made of polyamide are known from the state of the art. A problem with polyamide vapor barriers is that in rooms with high humidity, such as bathrooms or kitchens, high water vapor diffusion occurs even in winter, which can lead to condensation of water in the roof insulation and / or in the external wall insulation, and thus to structural damage.

[0006] The present invention is therefore based on the objective of creating an improved vapor barrier that is able to solve this problem while maintaining the desired properties of a vapor barrier. Furthermore, the vapor barrier should represent a marketable and competitive development.

[0007] In particular, the vapor barrier should allow for rapid drying at high relative humidity.

[0008] Furthermore, the vapor barrier should be suitable for use in the construction sector, especially for sealing purposes in the construction sector.

[0009] Furthermore, the vapor barrier should be easy to manufacture and largely free of solvents and, in particular, free of harmful substances in the home.

[0010] Furthermore, the vapor barrier should be durable.

[0011] This problem is solved with a planar track having the features specified in claim 1. Advantageous embodiments of the invention are specified in further claims.

[0012] The sheet-like membrane, suitable for the construction sector, comprises at least two layers, one of which is moisture-variable and made of a polyamide material, and the other of which is essentially moisture-independent. The two layers are preferably bonded together. Particularly preferably, the two layers are bonded together, preferably with a hot-melt adhesive. Alternatively, at least one of the two layers is produced by extrusion coating, the extrusion coating resulting in a material-bonded connection between the two layers. The moisture-variable layer exhibits an sd value that depends on the relative humidity. The moisture-independent layer is not moisture-variable. This means that it exhibits an sd value that is independent of, or essentially independent of, the relative humidity.

[0013] According to the invention, the polyamide material is a polyamide of polyamide type 4.6.

[0014] Polyamide type 4.6 has the following structural formula: The lUPAC name for polyamide of type 4.6 is poly[imino(i,6- dioxohexamethylene) iminotetramethylene].

[0015] The membrane exhibits good abrasion resistance, good temperature stability, and good aging resistance. It can be used as a moisture-variable vapor barrier.

[0016] In a particularly preferred embodiment of the invention, the moisture-variable layer comprises at least 40% (by weight), preferably at least 60% (by weight), and particularly preferably at least 80% (by weight) of polyamide of type 4.6. In a preferred embodiment, the moisture-variable layer is made of 100% polyamide of type 4.6.

[0017] In another preferred embodiment, the moisture-independent layer is designed as a nonwoven or woven fabric. The resulting sheet is therefore lightweight, stable, and easy to process.

[0018] The membrane has an sd value of less than 0.1 m at 92.5% relative humidity, preferably less than 0.01 m. This ensures rapid drying of rooms at high relative humidity. The risk of condensation and mold growth is reduced.

[0019] The moisture-variable layer preferably has a thickness of at least 10 pm and at most 200 pm.

[0020] In a further particularly preferred embodiment, the moisture-variable layer comprises at least a second polyamide material, which is a polyamide material different from type 4.6. Preferably, the moisture-variable layer is flame-retardant or flame-resistant. The properties of the moisture-variable layer can thus be further optimized.

[0021] Preferably, the moisture-variable layer is designed as a continuous film. In particular, the moisture-variable layer has no pores or openings. The moisture-variable layer is airtight. This means that the only transport mechanism for water vapor through the moisture-variable layer is diffusion, while convection cannot occur or can only occur to a negligible extent.

[0022] In a particularly preferred embodiment, the sd-value of the sheet membrane increases by at least a factor of 5, preferably by at least a factor of 10, and particularly preferably by at least a factor of 15, between 92.5% and 25% relative humidity. The sheet membrane thus exhibits pronounced humidity variability, which offers building physics advantages at both high and low relative humidity levels.

[0023] The moisture-independent layer preferably comprises polyethylene and / or polypropylene and / or polyester and / or polyurethane and / or thermoplastic polyurethane and / or ethylene-methyl acrylate copolymers and / or thermoplastic copolyester elastomers and / or mixtures or copolymers thereof. Both the moisture-independent and the moisture-variable layers can thus be produced from materials that are harmless to health.

[0024] The thickness of the moisture-independent layer is preferably between 10 pm and 200 pm, particularly preferably between 15 pm and 150 pm, and more preferably between 20 pm and 100 pm. This makes the moisture-independent layer easy and cost-effective to produce.

[0025] In particularly preferred embodiments of the invention, the sheet has at least a second moisture-independent layer, which is preferably designed as a nonwoven fabric, woven fabric, or coating. This improves the mechanical stability of the sheet.

[0026] In a further preferred embodiment, the planar web has at least a second moisture-variable layer comprising a polyamide material, wherein the polyamide contained therein is of polyamide type 4.6. Preferably, the first and the second moisture-variable layers are arranged on opposite sides of the moisture-independent layer and are metallurgically bonded to it.

[0027] The production of a planar web according to the invention is preferably carried out by processes known from the prior art such as extrusion, blown extrusion, co-extrusion, blown extrusion, lamination, calendering, doctor blade coating, rolling processes, melt casting processes, cast film processes or combinations thereof.

[0028] The use of a planar membrane according to the invention for use in the construction sector is also the subject of this invention. In particular, the use of a planar membrane according to the invention for sealing roofs, facades or walls in the construction sector is the subject of this invention.

[0029] The invention is explained in more detail below with reference to the drawings. These show:

[0030] Fig. aa a planar web i according to the invention with a moisture-variable layer 2 and a moisture-independent layer 3;

[0031] Fig. ib shows a second embodiment according to the invention of a planar track 1 with two moisture-independent layers 3 and 4;

[0032] The figures are not depicted to scale.

[0033] Fig. 1a shows a planar web 1 according to the invention with a moisture-variable layer 2 and a moisture-independent layer 3. The moisture-variable layer 2 and the moisture-independent layer 3 are connected to each other over a large area via one side surface each and form a film-shaped unit.

[0034] Fig. ib shows a second embodiment according to the invention of a planar web 1 with two moisture-independent layers 3 and 4. The moisture-independent layers 3 and 4 are each arranged on one side of the moisture-variable layer 2 and are connected to it over a large area.

[0035] Also according to the invention is any combination of the embodiments of the planar track described in the figures and the description. In particular, individual features of the described embodiments can be combined with one another according to the invention. The planar track according to the invention is suitable not only for construction purposes but also for other areas of application. List of reference symbols

[0036] 1 flat strip

[0037] 2 moisture-variable layers

[0038] 3. Moisture-independent layer 4. Second moisture-independent layer

Claims

Patent claims 1. Planar membrane (i) for the construction sector, comprising at least two layers, wherein one layer (2) is moisture-variable and comprises a polyamide material, and the other layer (3) is essentially moisture-independent, characterized in that the polyamide material is a polyamide of polyamide type 4.

6.

2. Planar web (1) according to claim 1, characterized in that the moisture-variable layer (2) comprises at least 40% (by weight), preferably at least 60% (by weight), particularly preferably at least 80% (by weight) of polyamide of type 4.

6.

3. Planar web (1) according to claim 1 or 2, characterized in that the moisture-independent layer (2) is designed as a nonwoven or woven fabric.

4. Planar web (1) according to claim 1, 2 or 3, characterized in that the planar web (1) has an sd value at 92.5% relative humidity of less than 0.1m, preferably less than 0.1m, particularly preferably less than 0.01m.

5. Planar web (1) according to one of claims 1-4, characterized in that the moisture-variable layer (2) has a thickness of at least 10 pm and at most 200 pm.

6. Planar web (1) according to one of claims 1-5, characterized in that the moisture-variable layer (2) comprises at least a second polyamide material which is a polyamide material different from type 4.6 and / or that the moisture-variable layer (2) is designed to be flame-retardant or flame-resistant. 7- Planar web (1) according to one of claims 1-6, characterized in that the sd value of the planar web (1) increases by at least a factor of 5, preferably by at least a factor of 10, particularly preferably by at least a factor of 15 between 92.5% relative humidity and 25% relative humidity.

8. Planar web (1) according to one of claims 1-7, characterized in that the moisture-independent layer (3) comprises polyethylene and / or polypropylene and / or polyester and / or polyurethane and / or thermoplastic polyurethane and / or ethylene-methyl acrylate copolymers and / or thermoplastic copolyester elastomers and / or copolymers or mixtures of the aforementioned materials and / or that the moisture-independent layer (3) is between 10pm and 200pm thick, preferably between 15pm and 150pm, particularly preferably between 20pm and 100pm.

9. Planar web (1) according to one of claims 1-8, characterized in that the planar web (1) has at least a second moisture-independent layer (4), which is preferably designed as a nonwoven fabric or woven fabric or as a coating.

10. Use of a planar membrane (1) according to one of claims 1 to 9 for sealing in the construction sector.

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