DE29811128U1 - Roofing membrane - Google Patents

Description

22 June 1998 .* ·* » I &idigr; !**· · *···· "j Müller-Bore & Partner

Applicant: Lenzing Aktiengesellschaft

"Underlayment"

Our reference: L 1533 - ru / ro

Description

The invention relates to an underlay membrane as described in claim 1.

The purpose of roof underlays is to protect the structural components underneath a roof covering or facade from penetrating contaminants such as dust and soot, as well as from moisture. Another task is to drain moisture from the inside of the building to the outside. Suitable roof underlays must therefore be permeable to water vapor, but surface-waterproof.
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Such underlays are known from the state of the art:

EP 0 109 928 describes a support material consisting of a surface structure impregnated with an impregnating compound, whereby a random fiber fleece can be used as the surface structure. A thick fleece is required for sufficient stability. The impregnation leads to products with a very high surface weight. Handling during installation is made more difficult.

EP 0 708 212 describes an underlayment with a three-layer structure, where a barrier layer consisting of a plastic film is embedded between two fleece layers. For reinforcement, a mesh can be inserted between the plastic film and the outer fleece layer for mechanical reinforcement. The layers are connected by an adhesive. Hydrolysis, UV radiation and other weather influences can cause the layers to dissolve.

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DE 296 09 139 U1 claims a flexible underlayment consisting of a grid-like fabric that is laminated with a film on at least one side. The underlayment can also be coated with a textile fleece. Here too, hydrolysis, UV radiation and other weather influences can cause the layers to dissolve.

EP 0 169 308 describes an underlay consisting of a PU film, a fleece layer and a net. During production, the net is placed on the fleece layer and the PU film is extruded onto this layer. The fleece layer serves as a moisture reservoir. The underlay is laid so that the fleece layer faces the interior of the building. There is no direct adhesion of the net to the fleece.

The problem with multi-layer composites is the adhesion of the layers to one another. The connection between the layers of the underlayment should not come apart during installation and especially during its lifetime, when the underlayment is exposed to high temperature and humidity fluctuations, as otherwise the desired function will no longer be provided.

Another problem is the handling, stability and safety during installation. Thin underlay membranes are easier to handle, but usually have the disadvantage that they can be easily damaged. Smooth membranes are difficult to walk on, especially when wet.

It has been shown that a fleece layer is not absolutely necessary as a moisture reservoir. By omitting the fleece layer, particularly thin and light composites can be produced. However, these have the disadvantage of a lack of mechanical stability, especially during installation work, and a lack of slip resistance, especially when wet. In order to protect the surface membrane from damage caused by the stress during installation and to avoid the disadvantages mentioned, a fleece can also be applied to the composite. For this purpose, the fleece layer can

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be made particularly thin so that it is still easy to handle. The underlay is then laid so that the underlay is laid with the fleece layer facing outwards. The mechanical stability can be further reinforced by a net.

The invention aims to create an underlayment that is characterized by easy handling, high stability and good walkability.

The underlayment according to the invention, consisting of at least one fleece or nonwoven layer, an open-mesh reinforcing element and a water vapor-permeable but waterproof layer, is characterized in that the fleece layer is intimately connected to a first thermoplastic elastomer layer and the open-mesh reinforcing element on the side of the composite facing away from the fleece layer is completely enclosed between the first thermoplastic elastomer layer and a second thermoplastic elastomer layer and the first thermoplastic elastomer layer is predominantly fused to the second thermoplastic elastomer layer.

Another requirement for roof underlays is high water vapor permeability while being waterproof. Thermoplastic elastomers (TPE) have proven to be particularly suitable for use in roof underlays, as their monolithic structure enables the formation of dense surface layers, without micro-holes, with high water vapor permeability.

Suitable thermoplastic elastomers (TPE) include thermoplastic polyetheresters, thermoplastic polyurethanes, thermoplastic polyetherimides and thermoplastic polyetheramide block copolymers. The choice of the suitable elastomer is left to the expert.

The thermoplastic elastomer of the first coating is present in an amount of

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10 to 70 g/m ² , preferably 10 to 40 g/m ² is applied to the fleece layer. Depending on requirements, this layer can be flame-retardant and provided with UV protection. The UV protection agents and the flame-retardant substances can be incorporated into the thermoplastic elastomer using conventional methods.

According to the invention, the fleece or the fleece layer is intimately connected to the first thermoplastic elastomer layer, which can be achieved if the first layer is extruded onto the fleece layer.

A random fiber fleece is preferably used as the fleece layer, with particularly suitable materials being polyolefins such as polypropylene. The basis weight of the fleece layer can be from 10 to 50 g/m ² , preferably from 15 to 30 g/m ² .

Open-mesh fabrics, knitted fabrics and nets, preferably made of polyolefins, are suitable as open-mesh reinforcement elements. HDPE (high density polyethylene) polymer is particularly suitable. The mesh size can be between 3 and 30 mm.

The second elastomer layer preferably consists of the same thermoplastic elastomer as the first elastomer layer. If required, this can be made flame-retardant.

The second thermoplastic elastomer layer is applied in an amount sufficient to completely cover the open mesh reinforcing element and thus enclose it between the first thermoplastic elastomer layer and the second thermoplastic elastomer layer.

The water vapor permeability can be expressed by the diffusion-equivalent air layer thickness (S _d value). The roof underlay has a water vapor permeability with an S _d value of less than or equal to 0.30 m, preferably an S _d value of less than or equal to 0.12 m.

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According to a further preferred embodiment, the underlayment is provided with a second fleece layer which is applied to the side of the underlayment opposite the first fleece layer. This provides protection for the water vapor-permeable but waterproof layer against damage from rough surfaces, in particular wooden formwork. The second fleece layer can have a basis weight of 10 to 60 g/m ² , preferably 20 to 40 g/m ² .

The underlayment is particularly suitable as an underlayment for pitched roofs and is laid on the roof in such a way that the fleece side faces outwards and thus forms the walkable surface.

The underlayment is also suitable as a wind barrier for facade cladding.

A preferred method for producing an underlayment consisting of at least one fleece or fleece layer, an open-mesh reinforcing element and a water vapor-permeable but waterproof layer is characterized in that in a first step a fleece layer is coated with a first thermoplastic elastomer and in a second step the composite formed is covered with an open-mesh reinforcing element on the side facing away from the fleece layer and at the same time a further thermoplastic elastomer layer is applied, whereby the open-mesh reinforcing element is embedded between the first thermoplastic elastomer layer and the second thermoplastic elastomer layer and the first is predominantly fused to the second thermoplastic elastomer layer.

In contrast to laminating with an adhesive, varnish, glue, etc., in which a substrate is bonded to another prefabricated substrate using an intermediate laminating agent, a coating creates an intimate bond between the components - nonwoven layer as carrier substance and thermoplastic elastomer as substrate - and thus a

22 June 1998 "&Idigr; I · ·»»» · · .·· Müller-Bore &. Partner

particularly good adhesion can be achieved.

It has been shown that particularly good adhesion between the layers can be achieved with the two-stage coating in two steps. This is because the optimal temperatures required for good adhesion between the different materials can be used, thus achieving a close bond between the layers.

In the first step, the elastomer is applied to the fleece layer in an amount of 10 to 70 g/m ² , preferably 10 to 30 g/m ² . The coating can be carried out by extrusion coating, whereby the elastomer melt can be applied in the roller gap of a pair of rollers. The optimum temperature for an intimate bond can be determined for the material pairings of coating material and fleece layer through tests. For example, the temperature during application is greater than 230 ^° C.

The composite formed in this way is called a membrane. An intimate connection between the fleece layer as the carrier substance and the elastomer layer as the substrate exists if the substrate cannot be separated from the carrier substance without a large part of the substrate remaining stuck to the carrier substance or being destroyed.

A random fiber fleece is preferably used as the fleece layer, with particularly suitable materials being polyolefins such as polypropylene. The basis weight of the fleece layer can be from 10 to 50 g/m ² , preferably from 15 to 30 g/m ² .

In the second process step, the composite from the first step is coated with another elastomer, thus forming a second elastomer layer. For mechanical reinforcement, this composite is covered with an open-mesh reinforcing element on the side facing away from the fleece layer, and at the same time, another thermoplastic elastomer layer is applied, with the open-mesh reinforcing element being sandwiched between the first thermoplastic layer.

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static elastomer layer and the second thermoplastic elastomer layer.

Preferably, the same elastomer is used for coating in the second step as in the first step.

Open-mesh reinforcing elements such as open-mesh fabrics, knitted fabrics and nets are suitable as reinforcing elements, preferably made of polyolefins. A HDPE (high density polyethylene) polymer is particularly suitable. The mesh width can be from 3 to 30 mm. The open-mesh reinforcing element can be flame-retardant.

The coating in the second step is preferably carried out by means of extrusion coating and can be carried out as in the first step. The temperature of the elastomer is selected in such a way that when the elastomer comes into contact with the membrane, the surface of the elastomer layer of the membrane is slightly melted and thus an intimate connection between the layers is achieved by extensive fusion of the elastomer layers and thus the first elastomer layer is largely fused with the second elastomer layer. The meshes of the open-mesh reinforcement element are formed, for example, by fabric tapes. The meshes are the areas between the fabric tapes of the open-mesh reinforcement element. Extensive fusion is the fusion of the touching surfaces of the elastomer layers in the meshes.

The high temperature also softens the open-mesh reinforcing element and thus a good bond between the elastomer layers and the open-mesh reinforcing element is achieved. The suitable temperatures can be determined through tests.

To produce a roofing membrane with a second fleece layer, in the second process step, the second fleece layer is guided together with the reinforcing element through the roller gap of a pair of rollers, whereby the

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thermoplastic polymer is introduced between the second fleece layer and the open-mesh reinforcing element.

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Example:
First step:

A melt of a commercially available thermoplastic elastomer (polyetherester type Arnitel EM 400 from DSM) was extruded via a slot die in the feed zone of a pair of rollers onto a polypropylene fleece with a basis weight of 20 g/m ² , the temperature of the elastomer being selected such that the melt penetrated into the fleece layer and thus an intimate bond was achieved between the elastomer and the fleece layer. The amount of elastomer was 35 g/m ² .

Second step:

The composite formed in the first step was covered on the side facing away from the fleece layer with a net made of HDPE mesh with a mesh size of 10 mm and together fed into the intake zone of a pair of rollers, whereby a molten thermoplastic elastomer (polyetherester type Arnitel EM 400 from DSM) was extruded from a slot die onto the surface of the web on which the net was located. Enough thermoplastic material was applied so that the net was completely surrounded by the polymer. The temperature of the melt was chosen so that the surface of the web formed in the first step was slightly melted and thus good adhesion to the second elastomer layer was achieved.

A roof underlay with the following properties was obtained:
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Surface weight: 120 g/m ²

Tear resistance: 250 N / 50 mm DIN 53 354

Needle pull-out force: 200 N DIN 54 301

Sd value: 0.12 m DIN 52 615

In summary, the invention relates to an underlay membrane consisting of at least one fleece layer, an open-mesh reinforcing element and

22 June 1998 · J· J J JJ.. J J*..* Müller-Bore & Partner

a water vapor-permeable but waterproof layer. The underlayment according to the invention is characterized in that the fleece layer is intimately connected to a first thermoplastic elastomer layer and the open-mesh reinforcing element on the side of the composite facing away from the fleece layer is completely enclosed between the first thermoplastic elastomer layer and a second thermoplastic elastomer layer and the first thermoplastic elastomer layer is predominantly fused to the second thermoplastic elastomer layer.

Claims (10)

22 June 1998 .*"··**· ·* ·· · ··..* Müller-Bore & Partner Applicant: Lenzing Aktiengesellschaft "Unterspannbahn" Our reference: L 1533 - ru / ro Claims 1. Underlayment consisting of at least one fleece layer, an open-mesh reinforcing element and a water vapor-permeable but waterproof layer, characterized in that the fleece layer is intimately connected to a first thermoplastic elastomer layer and the open-mesh reinforcing element on the side of the composite facing away from the fleece layer is completely enclosed between the first thermoplastic elastomer layer and a second thermoplastic elastomer layer and the first thermoplastic elastomer layer is predominantly fused to the second thermoplastic elastomer layer. 2. Underlayment according to claim 1, characterized in that thermoplastic polyetheresters, thermoplastic polyurethanes, thermoplastic polyetherimides and thermoplastic polyetheramide block copolymers are used as thermoplastic elastomers (TPE). 3. Underlayment according to claim 1 or 2, characterized in that the first elastomer layer has a basis weight of 10 to 70 g/m ² , preferably 10 to 30 g/m ² . 4. Underlayment according to one of the preceding claims, characterized in that the first elastomer layer is flame-retardant and has UV protection. 5. Underlayment according to one of the preceding claims, characterized in that the fleece layer has a basis weight of 10 to 50 g/m ² , preferably 10 to 30 g/m ² . 22 June 1998 .··..**. .**.." · *·· · Müller-Bore & Partner 6. Underlayment according to one of the preceding claims, characterized in that an open-mesh fabric, knitted fabric or net, preferably made of an HDPE polymer, is used as the open-mesh reinforcing element. 7. Underlayment according to one of the preceding claims, characterized in that the second elastomer layer consists of the same thermoplastic elastomer as the first elastomer layer. 8. Underlayment according to one of the preceding claims, characterized in that the water vapor permeability has an S _d value of less than or equal to 0.30 m, preferably an S _d value of less than or equal to 0.12 m. 9. Underlayment according to one of the preceding claims, characterized in that a second fleece layer is applied to the side of the underlayment opposite the first fleece layer. 10. Underlayment according to one of the preceding claims, characterized in that the second fleece layer has a basis weight of 10 to 60 g/m ² , preferably 20 to 40 g/m ² .