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Title:
A SEALING DEVICE WITH AT LEAST ONE HEAT-WELDABLE SHORT EDGE
Document Type and Number:
WIPO Patent Application WO/2021/229024
Kind Code:
A2
Abstract:
The invention is directed to a sealing device (1) comprising a waterproofing layer (2) and a layer of non-woven fabric (3) and having at least one heat-weldable short edge obtained by subjecting at least one of the short edge portions (4, 5) of the layer of non-woven fabric (3) to a heat-treatment. The invention is also directed to a method for producing a sealing device having at least one heat-weldable short edge, to a method for covering a substrate using the sealing devices of the present invention, and to a waterproofed structure.

Inventors:
FLÜCK ARMIN (CH)
ROSKAMP ROBERT (CH)
KNEBEL OLIVER (CH)
SCHÖNBRODT SIMON (CH)
Application Number:
PCT/EP2021/062765
Publication Date:
November 18, 2021
Filing Date:
May 12, 2021
Export Citation:
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Assignee:
SIKA TECH AG (CH)
International Classes:
B32B3/02; B32B3/06; B32B5/00; B32B5/02; B32B5/14; B32B7/02; B32B7/05; B32B7/12
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Claims:
Claims

1. A sealing device (1 ) having two primary exterior surfaces, a transverse width (W) defined by long edges (e1 , e2), and a longitudinal length (L) defined by short edges (e3, e4), the sealing device comprising: i A waterproofing layer (2) comprising at least one thermoplastic polymer P1 and having a first major surface and a second major surface separated from the first major surface by a thickness and ii A layer of non-woven fabric (3) comprising at least one thermoplastic polymer P2 and covering at least a portion of the second major surface of the waterproofing layer (2), wherein the layer of non-woven fabric (3) has first and second short edge portions (4, 5) extending along the short edges (e3, e4) of the sealing device (1) and a center portion (6) extending between the first and second short edge portions (4, 5) and wherein the capillarity for water, determined by means of the method cited in the description, of the layer of non-woven fabric (3) in the first and/or second short edge portions (4, 5) is lower than the capillarity for water of the layer of non-woven fabric (3) in the center portion (6).

2. The sealing device (1 ) according to claim 1 , wherein the sealing device (1) is in form of a roll.

3. The sealing device according to claim 1 or 2, wherein the capillarity for water, determined by means of the method cited in the description, of the layer of non-woven fabric (3) in the first and/or second short edge portions (4, 5) is at least 10%, preferably at least 20% lower than the capillarity for water of the layer of non-woven fabric (3) in the center portion (6).

4. The sealing device according to any one of previous claims, wherein the second major surface of the waterproofing layer (2) has first and second long edge sections (7, 8) extending along the long edges

(e1 , e2) of the sealing device (1 ) and wherein at least one of the long edge sections (7, 8) is not covered with the layer of non-woven fabric

(3).

5. The sealing device according to any one of previous claims, wherein the layer of non-woven fabric (3) has a mass per unit area of 25 - 500 g/m2, preferably 35 - 350 g/m2

6. The sealing device according to any one of previous claims, wherein the outer surface of the layer of non-woven fabric (3) on the side opposite to the waterproofing layer constitutes one of the two primary exterior surfaces of the sealing device (1 ).

7. The sealing device according to any one of previous claims obtained by subjecting a pre-formed sealing device comprising a waterproofing layer (2) comprising at least one thermoplastic polymer P1 and a layer of non-woven fabric (3) comprising at least one thermoplastic polymer P2 and having first and second short edge portions (4, 5) extending in a widthwise direction of the pre-formed sealing device (1) to a heat-treatment step comprising heating at least a part of the fibers contained in the first and/or second short edge portion (4, 5) of the non-woven fabric layer (3) to a temperature above the melting point of the at least one thermoplastic polymer P2 followed by subsequent cooling of said heated fibers.

8. The sealing device according to any one of previous claims, wherein the thermoplastic polymers P1 and P2 are selected from the group consisting of polyethylene, ethylene copolymers, copolymers of ethylene with vinyl acetate, polypropylene, and propylene copolymers.

9. The sealing device according to any one of previous claims, wherein the waterproofing layer (2) has a thickness determined by using the measurement method as defined in DIN EN 1849-2 standard of 0.1 - 5.0 mm, preferably 0.25 - 3.5 mm.

10. A method for producing a sealing device having at least one heat- weldable short edge, the method comprising steps of: a) Providing a membrane having two primary exterior surfaces and a transverse width (W) defined by long edges (e1 , e2), the membrane comprising a waterproofing layer (2) having a first major surface and a second major surface separated from the first major surface by a thickness and a layer of non-woven fabric (3) comprising at least one thermoplastic polymer P2 and covering at least a portion of the second major surface of the waterproofing layer (2), b) Cutting the membrane into a length (L) defined by first and second short edges (e3, e4), c) Subjecting the membrane to a heat-treatment step comprising heating at least part of the fibers contained in a first and/or a second short edge portion (4, 5) of the non-woven fabric layer (3) to a temperature above the melting point of the at least one thermoplastic polymer P2 followed by subsequent cooling of said heated fibers, wherein the first and second short edge portions (4, 5) extend along the short edges (e3, e4) of the membrane, and d) Optionally winding the heat-treated membrane obtained from step b) or c) into a roll.

11. The method according to claim 10, wherein step c) is conducted in such a manner that the capillarity for water of the layer of non-woven fabric (2) in the area of the first and/or second short edge portion (4, 5) is reduced to a value, which is lower, preferably at least 10% lower, than the capillarity for water of the layer of non-woven fabric (3) in a center portion (6) extending between the first and second short edge portions (4, 5).

12. The method according to claim 10 or 11, wherein step c) is conducted before step b) or simultaneously with step b).

13. The method according to any one of claims 10-12, wherein step c) is conducted by using a hot-air dryer, hot-pressing means, or heating rolls.

14. The method according to any one of claims 10-13, wherein the layer of non-woven fabric (3) has a mass per unit area of 25 - 500 g/m2, preferably 35 - 350 g/m2.

15. A method for covering a substrate, the method comprising steps of:

I) Applying a first sealing device (1 ) according to any one of claims 1-9 on the surface of the substrate such that the layer of non-woven fabric (3) is facing the surface of the substrate,

II) Applying a second sealing device (1’) according to any one of claims 1-9 on the surface of the substrate such that the layer of non-woven fabric (3’) is facing the surface of the substrate,

III) Overlapping a short edge region of the second sealing device (1’) over an overlapped short edge section of an upper side of the first sealing device (1),

IV) Bonding the opposing surfaces of the short edge region and the overlapped short edge section to each other using by heat-welding means. 16. The method according to claim 15, wherein the overlapped short edge section extends over the whole width (W1 ) of the waterproofing layer (2) of the first sealing device (1 ) and the short edge region extends over the whole width (W1’) of the waterproofing layer (2’) of the second sealing device (1’).

17. A waterproofed structure obtained by using the method according to claim 15 or 16.

Description:
A sealing device with at least one heat-weldable short edge

Technical field

The invention relates to the field of waterproofing of underground and above ground building constructions by using sealing devices comprising a waterproofing layer and non-woven fabric layer. In particular, the invention relates to sealing devices having at least one heat-weldable short edge.

Background of the invention

In the field of construction polymeric sheets, which are often referred to as membranes or panels, are used to protect underground and above ground constructions, such as basements, tunnels, and flat and low-sloped roofs, against penetration water. Waterproofing membranes are applied, for example, to prevent ingress of water through cracks that develop in the concrete structure due to building settlement, load deflection or concrete shrinkage. Roofing membranes are applied on a surface of roof substrate to be waterproofed, such as an insulation board, a cover board, or an existing roofing membrane in flat and low-sloped roof structures. Waterproofing membranes are typically provided as single-ply systems whereas roofing membranes are provided as single- or multiply systems depending on the application requirements. Single-ply membranes comprise a single waterproofing layer, which is usually mechanically stabilized with a reinforcement layer. Multi-ply membranes comprise multiple waterproofing layers having a different or similar polymeric composition. Single-ply membranes have the advantage of lower production costs compared to the multi-ply membranes but they are also less resistant to mechanical damages caused by punctures of sharp objects.

Commonly used materials for roofing membranes include plastics, in particular thermoplastics such as plasticized polyvinylchloride (p-PVC), thermoplastic olefins (TPE-O, TPO), and elastomers such as ethylene-propylene diene monomer (EPDM). The roofing membranes are typically delivered to a construction site in form of rolls, transferred to the place of installation, unrolled, and adhered to the substrate to be waterproofed. The substrate on which the membrane is adhered may be comprised of variety of materials depending on the installation site. The substrate may, for example, be a concrete, metal, or wood deck, or it may include an insulation board or a recover board and/or an existing membrane.

Roofing membranes must be securely fastened to the roof substrate to provide sufficient mechanical strength to resist the shearing forces applied on it due to high wind loads. Roof systems are typically divided into two categories depending on the means used for fastening the roofing membrane to roof substrate. In a mechanically attached roof system, the roofing membrane is fastened to the roof substrate by using screws and/or barbed plates. Mechanical fastening enables high strength bonding but it provides direct attachment to the roof substrate only at locations where a mechanical fastener affixes the membrane to the surface, which makes mechanically attached membranes susceptible to flutter. Roofing membranes can also be adhesively adhered to the roof substrate by contact bonding or by using self-adhering membranes having a pre-applied layer of adhesive composition coated on one of the exterior surfaces of the membrane.

In order to create a continuous waterproofing seal on the surface of a substrate, the edge of adjacent membranes are overlapped to form sealable joints. The joints can then be sealed by bonding the opposing surfaces of the overlapped edges to each other by using an adhesive (“bonded seams”) or by heat-welding (“welded seams”). A sealing tape can also be used for bridging the gap between the top surfaces of overlapped edges. The choice of the technique used for bonding of the overlapped edges of the adjacent membranes depends on the material of the membranes. In case of thermoplastic membranes or membranes based on non-crosslinked elastomeric materials, the overlapped edges can be bonded to each other by heat-welding. In case of self-adhering membranes, an area extending along one of the longitudinal edges of the membrane is typically left free of the adhesive in order to enable joining of the overlapped edges by heat-welding or by using another type of adhesive.

Membranes comprising a layer of fiber material applied on the back side of a waterproofing layer are commonly in roofing applications. The layer of fiber material is typically a nonwoven fabric, such as a fleece or a felt. These types of membranes are also known as “felt-backed” or “fleece-backed” membranes. The layer of fiber material can be used to increase the mechanical stability of the waterproofing layer and/or to enable adhesive bonding of the membrane to a substrate using a specific adhesive and/or to form a barrier against migration of compounds from an adhesive layer to the waterproofing layer or vice versa. Due to the presence of the layer of fiber material, the overlapped edges of adjacent membranes typically cannot be bonded to each other by heat welding. Therefore, the fleece- and felt-backed membranes are usually provided with selvedge edges that are left free of the layer of fiber material to enable formation of welded-seams. However, membranes can be produced with longitudinal selvedge edges but not with widthwise selvedge edges since the transverse edges (“short edges”) are only formed when the membrane has been cut into a pre-determ ined length.

Consequently, even if membranes are provided with longitudinal selvedge edges, the seams formed between overlapped short edges must be sealed by adhesive bonding and/or by using sealing tapes, which increases the installation costs. There thus remains a need for a novel type of membrane having at least one heat-weldable short edge. Summary of the invention

The object of the present invention is to provide a sealing device comprising a waterproofing layer and a layer of non-woven fabric and at least one heat- weldable short edge.

Another object of the present invention is to provide a sealing device, which can be used for providing waterproofing and roofing systems, in which the seams between overlapped short edges of adjacent sealing devices can be adhered to each other by heat-welding.

The subject of the present invention is a sealing device as defined in claim 1.

It was surprisingly found out that a sealing device having a heat-weldable short edge can be obtained by subjecting a sealing device comprising a waterproofing layer and a layer of non-woven fabric to a heat-treatment step comprising heating at least a part of the fibers contained in a short edge portion of the non-woven fabric layer to a temperature above the melting point of the fibers to decrease the capillarity for water of the layer of non-woven fabric in the area of the short edge portion.

It has also been surprisingly discovered that a welded joint obtained by bonding overlapped short edge portions of two sealing devices of the present invention to each other by heat-welding fulfills the requirements as set forth in the UEAtc Technical Guide for the assessment of non-reinforced, reinforced and /or backed roof waterproofing systems made of FPO, December 2001. According to the UEAtc Technical Guide, a welded joint is generally considered satisfactory when in a tear testing, a break occurs outside of the welding seam between the joined layers.

One of the advantages of the sealing device of the present invention is that it enables providing waterproofing and, particularly roofing systems, in which the seams between overlapped short edge portions of adjacent sealing devices can be bonded to each other by heat-welding to provide heat-welded seams.

Another advantage of the sealing device of the present invention is that both short edge portions and long edge portions of adjacent sealing devices can be bonded to each other by heat-welding, which simplifies and decreases the costs of the installation costs.

Other subjects of the present invention are presented in other independent claims. Preferred embodiments of the invention are presented in the dependent claims.

Brief description of the Drawings

Fig. 1 shows a perspective view of a sealing device (1) having two primary exterior surfaces, a transverse width (W) defined by long edges (e1 , e2), and a longitudinal length (L) defined by short edges (e3, e4). The sealing device (1) comprises a waterproofing layer (2) having a first major surface and a second major surface and a layer of non-woven fabric (3) covering the second major surface of the waterproofing layer (2).

Fig. 2 shows a perspective view of the sealing device (1 ) of Figure 1 , wherein the waterproofing layer (2) has a transverse width (W1) and a longitudinal length (L1 ) and the layer of non-woven fabric (3) has a transverse width (W2) and a longitudinal length (L2).

Fig. 3 shows a cross-section of the sealing (1) device depicted in Figure 2. Fig. 4 shows a cross-section a structure comprising a first sealing device (1 ) and a second sealing device (T), wherein a short edge region of the second sealing device (T) has been bonded to an overlapped short edge section of an upper side of the first sealing device (1 ). Detailed description of the invention

The subject of the present invention is a sealing device (1 ) having two primary exterior surfaces, a transverse width (W) defined by long edges (e1 , e2), and a longitudinal length (L) defined by short edges (e3, e4), the sealing device comprising: i A waterproofing layer (2) comprising at least one thermoplastic polymer P1 and having a first major surface and a second major surface separated from the first major surface by a thickness and ii A layer of non-woven fabric (3) comprising at least one thermoplastic polymer P2 and covering at least a portion of the second major surface of the waterproofing layer (2), wherein the layer of non-woven fabric (3) has first and second short edge portions (4, 5) extending along the short edges (e3, e4) of the sealing device (1) and a center portion (6) extending between the first and second short edge portions (4, 5) and wherein the capillarity for water, determined by means of the method cited in the description, of the layer of non-woven fabric (3) in the first and/or second short edge portions (4, 5) is lower than the capillarity for water of the layer of non-woven fabric (3) in the center portion (6).

Substance names beginning with "poly" designate substances which formally contain, per molecule, two or more of the functional groups occurring in their names. For instance, a polyol refers to a compound having at least two hydroxyl groups. A polyether refers to a compound having at least two ether groups. The term “polymer” designates a collective of chemically uniform macromolecules produced by a polyreaction (polymerization, polyaddition, polycondensation) where the macromolecules differ with respect to their degree of polymerization, molecular weight and chain length. The term also comprises derivatives of said collective of macromolecules resulting from polyreactions, that is, compounds which are obtained by reactions such as, for example, additions or substitutions, of functional groups in predetermined macromolecules and which may be chemically uniform or chemically non- uniform.

The term “elastomer” refers to any polymer or combination of polymers, which is capable of recovering from large deformations, and which can be, or already is, modified to a state in which it is essentially insoluble (but can swell) in a boiling solvent. Typical elastomers are capable of being elongated or deformed to at least 200% of their original dimension under an externally applied force, and will substantially resume the original dimensions, sustaining only small permanent set (typically no more than about 20%), after the external force is released. As used herein, the term “elastomer” may be used interchangeably with the term “rubber.”

The term “molecular weight” designates the molar mass (g/mol) of a molecule or a part of a molecule, also referred to as “moiety”. The term “average molecular weight” refers to number average molecular weight (M n ) of an oligomeric or polymeric mixture of molecules or moieties. The molecular weight may be determined by conventional methods, preferably by gel permeation- chromatography (GPC) using polystyrene as standard, styrene-divinylbenzene gel with porosity of 100 Angstrom, 1000 Angstrom and 10000 Angstrom as the column, and, depending on the molecule, tetrahydrofurane as a solvent, at 35 °C, or 1,2,4-trichlorobenzene as a solvent, at 160 °C.

The term “softening point” refers to a temperature at which compound softens in a rubber-like state, or a temperature at which the crystalline portion within the compound melts. The softening point can be determined by Ring and Ball measurement conducted according to DIN EN 1238 standard.

The term “melting temperature” designates a temperature at which a material undergoes transition from the solid to the liquid state. The melting temperature (Tm) is preferably determined by differential scanning calorimetry (DSC) according to ISO 11357-3:2018 standard using a heating rate of 2°C/min. The measurements can be performed with a Mettler Toledo DSC 3+ device and the Tm values can be determined from the measured DSC-curve with the help of the DSC-software. In case the measured DSC-curve shows several peak temperatures, the first peak temperature coming from the lower temperature side in the thermogram is taken as the melting temperature (T m ).

The term “glass transition temperature” (T g ) designates the temperature above which temperature a polymer component becomes soft and pliable, and below which it becomes hard and glassy. The glass transition temperature is preferably determined by dynamical mechanical analysis (DMA) as the peak of the measured loss modulus (G”) curve using an applied frequency of 1 Hz and a strain level of 0.1%.

The “amount or content of at least one component X” in a composition, for example “the amount of the at least one thermoplastic polymer P” refers to the sum of the individual amounts of all thermoplastic polymers P contained in the composition. Furthermore, in case the composition comprises 20 wt.-% of at least one thermoplastic polymer P, the sum of the amounts of all thermoplastic polymers P contained in the composition equals 20 wt.-%.

The term “room temperature” designates a temperature of 23°C.

The sealing device (1 ) of the present invention as shown in Figure 1 has two primary exterior surfaces, a transverse width (W) defined by long edges (e1 , e2), and a longitudinal length (L) defined by short edges (e3, e4). The term “primary exterior surface of the sealing” refers in the present disclosure to the outermost surfaces of the sealing device.

The sealing device comprises a waterproofing layer (2) to provide the sealing device with a sufficient watertightness required in waterproofing and roofing applications. The waterproofing layer (2) comprises at least one thermoplastic polymer P1 and has a first major surface and a second major surface separated from the first major surface by a thickness.

The sealing device (1 ) further comprises a layer of a non-woven fabric having first and second short edge portions (4, 5) extending along the short edges (e3, e4) of the sealing device (1) and a center portion (6) extending between the first and second short edge portions (4, 5). The first and second short edge portions (4, 5) are substantially rectangular elements having a length measured in widthwise direction of the sealing device (1 ) and a width measured in lengthwise direction of the sealing device (1), wherein the length preferably exceeds the width by a factor of at least 1.5, more preferably at least 2. The expression “extending along the short edges (e3, e4) is understood to mean that the longitudinal edges of the short edge portions (4, 5) are parallel to the short edges (e3, e4) of the sealing device (1 ). Preferably, the layer of non- woven fabric (3) is composed of the first and second short edge portions (4, 5) and the center portion (6), i.e. the sum of the surface areas of the first and second short edge portions (4, 5) and the center portion (6) equals the surface area of the layer of non-woven fabric.

The sealing device is preferably a pre-formed shaped article, more preferably a pre-formed waterproofing or roofing membrane. The term “pre-formed membrane” refers in the present disclosure to sheet-like articles, which have been formed before being applied on a surface of a substrate to be waterproofed. Particularly, the term “pre-formed membrane” refers to sheet-like articles, which have not been formed in situ, i.e. not been formed on the surface of the substrate to be waterproofed. Such pre-formed membranes are fabricated at a location that is typically remote from the construction site, brought to the site, for example, in the form of a roll and laid on a surface of a substrate to be waterproofed.

According to one or more embodiments, the sealing device is a waterproofing or roofing membrane, which has not yet been installed to a surface of a substrate to be waterproofed. According to one or more embodiments, the sealing device is provided in form of a roll. This enables more efficient transfer of the sealing device to the place of installation, such as a construction site, where the sealing device is typically unrolled, and adhered to the substrate to be waterproofed.

According to one or more embodiments, the capillarity for water of the layer of non-woven fabric (3) in the first and/or second short edge portion (4, 5) is at least 10%, preferably at least 20%, more preferably at least 25%, even more preferably at least 30%, still more preferably at least 35%, such as at least 40%, most preferably at least 45%, lower than in the center portion (6) of the layer of non-woven fabric (3). The lowered capillarity for water in the short edge portions of the layer of non-woven fabric have been found out to enable provision of sealing devices with heat-weldable short edges. The expression heat-weldable is understood to mean that overlapped short edge portions of adjacent sealing devices can be bonded to each other by heat-welding to provide acceptable seam strength without the use of adhesive. The heat welding can be conducted by using a hot air tool, or by using an automatic welding device, such as an automatic hot-air welding device, for example Sarnamatic® 661 welding device. The capillarity for water is determined by using the measurement method as described below. Method for determining capillarity for water

The capillarity for water of the layer of non-woven fabric is determined according to the following procedure.

In the measurement procedure, a rectangular sample having dimensions of 220 x 150 mm (height x width) is cut from a sealing device comprising a waterproofing layer and the non-woven fabric covering a surface of the waterproofing layer. The sample is then hanged partly immersed in a colored water (methylene blue, 0.5 g/l) having a controlled temperature of 23°C. The sample is held in place for 24 hours days with a 20 mm height of the bottom edge of the sealing device immersed in the colored water. The height to which the colored water has risen during the measurement is recorded as a representative value for the capillarity of water of the layer of non-woven fabric.

Preferably, the waterproofing layer (2) and the layer of non-woven fabric (3) are substantially rectangular elements having a longitudinal length (L1, L2) and a transverse width (W1 , W2), respectively, as shown in Figure 2. It is also preferred that the longitudinal length (L1, L2) exceeds the transverse width (W1 , W2) by a factor of at least 1.5, more preferably of at least 2. According to one or more embodiments, the layer of non-woven fabric (3) covers at least 75%, more preferably at least 85%, most preferably at least 90% of the area of the second major surface of the waterproofing layer (2).

The layer of non-woven fabric (3) is preferably directly or indirectly connected over its substantially entire surface to the second major surface of the waterproofing layer (2). The term “substantially entire surface” is understood to mean in the context of the present disclosure at least 95%, preferably at least 99% of the corresponding surface. The expression “directly connected” is understood to mean that no further layer or substance is present between the layers and that the opposing surfaces of the layers are directly bonded to each other or adhere to each other. At the transition area between the two layers, the materials of the layers can also be present mixed with each other. The layer of non-woven fabric (3) and the waterproofing layer (2) can be indirectly connected to each other, for example, via a connecting layer, such as a layer of adhesive.

According to one or more embodiments, the layer of non-woven fabric (3) is directly connected over its substantially entire surface to the second major surface of the waterproofing layer (2), as shown in Figure 3. In these embodiments, it may be preferred that the layer of non-woven fabric (3) is partially embedded into the waterproofing layer (2). The expression “partially embedded” is understood to mean that a portion of the fibers contained in the layer of non-woven fabric (3) are embedded into the waterproofing layer (2), i.e. covered by the matrix of the waterproofing layer (2) whereas other portion of the fibers are not embedded into the waterproofing layer (2).

According to one or more embodiments, the layer of non-woven fabric (3) has been thermally laminated to the second major surface of the waterproofing layer (2) in a manner that gives direct bonding between the layer of non-woven fabric (3) and the waterproofing layer (2). The term “thermal lamination” refers to a process, in which the layers are bonded to each by the application of thermal energy. In particular, the term “thermal lamination” refers to a process comprising partially melting at least one of the layers upon application of thermal energy followed by a cooling step, which results in formation of a bond between the layers without using an adhesive.

According to one or more further embodiments, the layer of non-woven fabric (3) is indirectly connected over its substantially entire surface to the second major surface of the waterproofing layer (2) via a layer of an adhesive. The type of adhesive used for bonding of the layer of non-woven fabric to the waterproofing layer is not particularly restricted. Suitable adhesives include, for example, reactive 1- and 2-component reactive adhesives, hot-melt adhesives, and solvent- and water-based adhesives.

According to one or more embodiments, the second major surface of the waterproofing layer (2) has first and second long edge sections (7, 8) extending along the long edges (e1 , e2) of the sealing device (1 ) and wherein at least one of the long edge sections (7, 8) is not covered with the layer of non-woven fabric (3). According to one or more embodiments, one of the long edge sections (7, 8) is not covered with the layer of non-woven fabric (3) whereas the other one is covered with the layer of non-woven fabric, as shown in Figures 1 and 2.

The term “non-woven fabric” designates in the present disclosure materials composed of fibers, which are bonded together by using chemical, mechanical, or thermal bonding means, and which are neither woven nor knitted. Non- woven fabrics can be produced, for example, by using a carding or needle punching process, in which the fibers are mechanically entangled to obtain the non-woven fabric. In chemical bonding, chemical binders such as adhesive materials are used to hold the fibers together in a non-woven fabric.

Preferably, the layer of non-woven fabric has a mass per unit weight of at least 25 g/m 2 , more preferably at least 35 g/m 2 , still more preferably at least 55 g/m 2 , such as at least 75 g/m 2 . According to one or more embodiments, the layer of non-woven fabric has a mass per unit weight of 25 - 500 g/m 2 , preferably 35 - 400 g/m 2 , more preferably 55 - 350 g/m 2 , even more preferably 75 - 350 g/m 2 , still more preferably 95 - 300 g/m 2 . The mass per unit area of a non-woven fabric can be determined by measuring the mass of test piece of the non- woven fabric having a given area and dividing the measured mass by the area of the test piece. Preferably, the mass per unit area of a non-woven fabric is determined as defined in ISO 9073-18:2007 standard.

According to one or more embodiments, the outer surface of the layer of non- woven fabric (3) on the side opposite to the waterproofing layer (2) constitutes one of the two primary exterior surfaces of the sealing device (1 ).

According to one or more embodiments, the sealing device (1) is obtained by subjecting a pre-formed sealing device comprising a waterproofing layer (2) comprising at least one thermoplastic polymer P1 and a layer of non-woven fabric (3) comprising at least one thermoplastic polymer P2 and having first and second short edge portions (4, 5) extending in a widthwise direction of the pre formed sealing device (1 ) to a heat-treatment step comprising heating at least a part of the fibers contained in the first and/or second short edge portion (4, 5) of the non-woven fabric layer (3) to a temperature above the melting point of the at least one thermoplastic polymer P2 followed by subsequent cooling of said heated fibers and optionally winding of the thus obtained sealing device into a roll. The heating of the fibers of the layer of non-woven fabric (3) can be conducted using any conventional means, such as by using a hot-air dryer or contact heating means, such as a hot-press or heating rolls.

The detailed composition of the waterproofing layer is not particularly restricted and it also depends on the intended application of the sealing device. For example, in case the sealing device is used in roofing applications, the composition of the waterproofing layer is preferably selected such that the sealing device fulfils the general requirements for roofing membranes, in particular the general requirements as defined in DIN 20000-201:2015-08 standard.

In case the sealing device is used in roofing applications, it may be preferred that sealing device shows:

- an impact resistance measured according to EN 12691 : 2005 standard in the range of 200 - 1500 mm and/or

- a longitudinal and a transversal tensile strength measured at a temperature of 23°C according to DIN ISO 527-3:2019-02 standard of at least 5 MPa and/or

- a longitudinal and transversal elongation at break measured at a temperature of 23°C according to DIN ISO 527-3:2019-02 standard of at least 300% and/or

- a water resistance measured according to EN 1928 B:2000 standard of 0.6 bar for 24 hours and/or

- a maximum tear strength measured according to EN 12310-2:2018 standard of at least 100 N.

According to one or more embodiments, the at least one thermoplastic polymer P1 and the at least one thermoplastic polymer P2 are compatible and/or at least partially miscible with each other. By the polymers being “compatible” is understood to mean that the properties of a blend composed of the at least one thermoplastic elastomer P1 and the at least one polymer P2 are not inferior to those of the individual polymers P1 and P2. A blend of compatible polymers is commonly characterized as an immiscible polymer blend that exhibits macroscopically uniform physical properties whereas a blend of miscible polymers is commonly characterized as a homogeneous polymer blend.

According to one or more embodiments, the at least one thermoplastic polymer P1 and the at least one thermoplastic polymer P2 are at least partially miscible with each other. By the polymers being “miscible” is understood to mean that a polymer blend composed of the at least one thermoplastic polymer P1 and the at least one thermoplastic polymer P2 has a negative Gibbs free energy and heat of mixing. The polymer blends composed of entirely miscible polymer components tend to have one single glass transition point (T g ), which can be measured using dynamic mechanical thermal analysis (DMTA). The glass transition point can be determined, for example, as the peak of the measured tan delta curve (ratio of storage and loss moduli). According to one or more embodiments, the at least one thermoplastic polymer P1 and the at least one thermoplastic polymer P2 are selected from the group consisting of polyethylene, ethylene copolymers, copolymers of ethylene with vinyl acetate, polypropylene, and propylene copolymers. The term “ethylene copolymer” refers to copolymers comprising at least 50 wt.- %, more preferably at least 60 wt.-% of ethylene-derived units, based on the weight of the copolymer. The term “propylene copolymer” refers to copolymers comprising at least 50 wt.-%, more preferably at least 60 wt.-% of propylene- derived units, based on the weight of the copolymer.

According to one or more embodiments, the at least one thermoplastic polymer P1 and the at least one thermoplastic polymer P2 are selected from the group consisting of polyethylene, ethylene-a-olefin copolymers, copolymers of ethylene with vinyl acetate, polypropylene, and propylene-a-olefin copolymers.

Suitable polyethylenes include, for example, ethylene homopolymers, such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), preferably having a melting temperature (Tm) determined by differential scanning calorimetry (DSC) according to ISO 11357-3:2018 standard using a heating rate of 2°C/min of at or above 100°C, preferably at or above 105°C, more preferably at or above 110°C.

Suitable ethylene-a-olefin copolymers include, for example, random and block copolymers of ethylene and one or more C3-C20 a-olefin monomers, in particular one or more of propylene, 1 -butene, 1-pentene, 1 -hexene, 1- heptene, 1-octene, 1-decene, 1-dodecene, and 1 -hexadodecene, preferably comprising at least 60 wt.-%, more preferably at least 65 wt.-% of ethylene- derived units, based on the weight of the copolymer.

Suitable copolymers of ethylene and vinyl acetate include those having a content of a structural unit derived from vinyl acetate in the range of 4 - 70 wt.- %, in particular 4 - 60 wt.-%, based on the weight of the copolymer.

Suitable polypropylenes include, for example, isotactic polypropylene (iPP), syndiotactic polypropylene (sPP), and homopolymer polypropylene (hPP), preferably having a melting temperature (T m ) determined by differential scanning calorimetry (DSC) according to ISO 11357-3:2018 standard using a heating rate of 2°C/min of at or above 100°C, preferably at or above 105°C, more preferably at or above 110°C.

Suitable propylene-a-olefin copolymers include propylene-ethylene random copolymers, propylene-ethylene block copolymers, and random and block copolymers of propylene and one or more C4-C20 a-olefin monomers, in particular one or more of 1 -butene, 1-pentene, 1 -hexene, 1- heptene, 1-octene, 1-decene, 1-dodecene, and 1 -hexadodecene, preferably comprising at least 60 wt.-%, more preferably at least 65 wt.-% of propylene-derived units, based on the weight of the copolymer.

Further suitable propylene-a-olefin copolymers include heterophasic propylene copolymers. Heterophasic copolymers are heterophasic polymer systems comprising a high crystallinity base polyolefin and a low-crystallinity or amorphous polyolefin modifier. The heterophasic phase morphology consists of a matrix phase composed primarily of the base polyolefin and a dispersed phase composed primarily of the polyolefin modifier. Commercially available heterophasic copolymers are reactor blends of the base polyolefin and the polyolefin modifier, also known as “in-situ TPOs” or “reactor TPOs or “impact copolymers (ICP)”. Heterophasic copolymers are typically produced in a sequential polymerization process, wherein the components of the matrix phase are produced in a first reactor and transferred to a second reactor, where the components of the dispersed phase are produced and incorporated as domains in the matrix phase.

Preferred heterophasic propylene copolymers contain a a high-crystallinity polypropylene having a peak melting point (T m ) of 100°C or more, preferably a propylene homopolymer and/or a random copolymer of propylene having a low comonomer content, as the base polymer and one or more ethylene copolymer(s) having a glass transition temperature of -20°C or less, such as ethylene/propylene-rubber (EPR), as the polyolefin modifier. Heterophasic copolymers comprising a polypropylene homopolymer as the base polymer are often referred to as heterophasic propylene copolymers (HECO) whereas heterophasic copolymers comprising a polypropylene random copolymer as the base polymer are often referred to as random heterophasic propylene copolymers (RAHECO). The term “heterophasic propylene copolymer” encompasses in the present disclosure both the HECO and RAHECO types of heterophasic propylene copolymers.

According to one or more embodiments, the at least one thermoplastic polymers P1 and P2 are selected from the group consisting of polyethylene, ethylene-a-olefin copolymers, and copolymers of ethylene with vinyl acetate. According to one or more embodiments, the at least one thermoplastic polymers P1 and P2 are selected from the group consisting of polypropylene, and propylene-a-olefin copolymers.

According to one or more embodiments, the at least one thermoplastic polymer P1 comprises at least one heterophasic propylene copolymer P11. Generally, the expression “the at least one component X comprises at least one component XN”, such as “the at least one thermoplastic polymer P1 comprises at least one heterophasic propylene copolymer P11” is understood to mean in the context of the present disclosure that the composition comprises one or more heterophasic propylene copolymers P11 as representatives of the at least one thermoplastic polymer P1.

According to one or more embodiments, the at least one heterophasic propylene copolymer P11 comprises:

-A) at least one polypropylene having a melting point (T m ) of 100°C or more, preferably a propylene homopolymer and/or a random copolymer of propylene having a comonomer content of less than 10 wt.-%, preferably less than 5 wt.- %, based on the weight of the copolymer and

- B) at least one polyolefin having a glass transition temperature (T g ) of -20°C or less, preferably an ethylene copolymer having a comonomer content of at least 5 wt.-%, preferably at least 10 wt.-%, based on the weight of the copolymer, preferably having a glass transition temperature (T g ) of -25°C or less, more preferably -35°C or less, preferably an ethylene-propylene rubber (EPR), wherein the at least one heterophasic propylene copolymer P11 comprises a matrix phase composed primarily of A) and a dispersed phase composed primarily of B).

According to one or more embodiments, the at least one heterophasic propylene copolymer P11 is a reactor blend of A) and B), wherein the reactor blend has preferably been obtained by using a sequential polymerization process, wherein constituents of the matrix phase are produced in a first reactor and transferred to a second reactor where constituents of the dispersed phase are produced and incorporated as domains into the matrix phase.

Particularly suitable heterophasic propylene copolymers include, for example, “reactor TPOs” and “soft TPOs” produced with LyondellBasell ' s Catalloy process technology, which are available under the trade names of Adflex®, Adsyl®, Clyrell®, Hifax®, Hiflex®, and Softell®, such as Hifax® CA 10A,

Hifax® CA 12A, and Hifax® CA 60 A, and Hifax CA 212 A. Further suitable heterophasic propylene copolymers are commercially available under the trade name of Borsoft® (from Borealis Polymers), such as Borsoft® SD233 CF.

According to one or more embodiment, the at least one thermoplastic polymer P1 comprises, in addition to or instead of the at least one heterophasic propylene copolymer P11, at least one propylene-ethylene copolymer P12, preferably having an ethylene content of 5 - 20 wt.-%, more preferably 9 - 18 wt.-%, even more preferably 12 - 18 wt.-%, even more preferably 12 - 16 wt.- %, based on the weight of the propylene-ethylene copolymer.

According to one or more embodiments, the at least one propylene-ethylene copolymer P12 has

- a flexural modulus at 23°C determined according to ISO 178 standard of not more than 100 MPa, preferably not more than 75 MPa, more preferably not more than 50 MPa, even more preferably not more than 35 MPa, still more preferably not more than 25 MPa and/or

- a melt flow rate (230°C/2.16 kg) determined according to ISO 1133 standard of not more than 50 g/10 min, preferably not more than 35 g/10 min, more preferably not more than 25 g/10 min, even more preferably not more than 15 g/10 min and/or

- a density at 23°C determined according to ASTM D-792 standard of 0.850 - 0.900 g/cm 3 , preferably 0.855 - 0.890 g/cm 3 and/or - a xylene cold soluble content determined according to ISO 16152-2005 standard of at least 85 wt.-%, preferably at least 90 wt.-%, more preferably at least 95 wt.-%, even more preferably at least 97.5 wt.-%.

Particularly suitable propylene-ethylene copolymers used as the at least one propylene-ethylene copolymer P11 include the propylene-ethylene copolymers, which are commonly characterized as “propylene-based elastomers”. These are commercially available, for example, under the trade name of Versify® (from Dow Chemicals) and under the trade name of Vistamaxx (from Exxon Mobil).

The amount of the at least one thermoplastic polymer P1 in the waterproofing layer is not particularly restricted. Preferably, the at least one thermoplastic polymer P1 comprises at least 35 wt.-%, more preferably at least 45 wt.-%, even more preferably at least 55 wt.-%, of the total weight of the waterproofing layer. According to one or more embodiments, the waterproofing layer comprises, as polymer basis, 35 - 95 wt.-%, preferably 45 - 90 wt.-%, more preferably 55 - 85 wt.-%, of the at least one thermoplastic polymer P1. The polymer basis of the waterproofing layer may comprise, in addition to the at least one thermoplastic polymer P1, other polymers or copolymers which are not allocated to the category of thermoplastic polymer P1.

The waterproofing layer can comprise, in addition to the at least one thermoplastic polymer P1, auxiliary components, for example, UV- and heat stabilizers, antioxidants, plasticizers, flame retardants, fillers, dyes, pigments such as titanium dioxide and carbon black, matting agents, antistatic agents, impact modifiers, biocides, and processing aids such as lubricants, slip agents, antiblock agents, and denest aids. The total amount of these auxiliary components is preferably not more than 60 wt.-%, more preferably not more than 50 wt.-%, even more preferably not more than 40 wt.-%, still more preferably not more than 35 wt.-%, based on the total weight of the waterproofing layer. Furthermore, the amount of the at least one thermoplastic polymer P2 in the layer of non-woven fabric is not particularly restricted. Preferably, the at least one thermoplastic polymer P2 comprises at least 50 wt.-%, more preferably at least 70 wt.-%, even more preferably at least 85 wt.-% of the total weight of the layer of non-woven fabric. According to one or more embodiments, the layer of non-woven fabric comprises, as polymer basis, 50 - 97.5 wt.-%, preferably 60 - 95 wt.-%, more preferably 70 - 90 wt.-%, even more preferably 75 - 90 wt.-% of the at least one thermoplastic polymer P2.

The layer of non-woven fabric can comprise, in addition to the at least one thermoplastic polymer P2, auxiliary components, for example, UV- and heat stabilizers, antioxidants, plasticizers, flame retardants, fillers, dyes, pigments such as titanium dioxide and carbon black, matting agents, antistatic agents, impact modifiers, biocides, and processing aids such as lubricants, slip agents, antiblock agents, and denest aids. The total amount of these auxiliary components is preferably not more than 30 wt.-%, more preferably not more than 25 wt.-%, even more preferably not more than 20 wt.-%, still more preferably not more than 15 wt.-%, based on the total weight of the waterproofing layer.

The thickness of the waterproofing layer is not particularly restricted, and it also depends on the intended application of the sealing device. Preferably, the waterproofing layer has a thickness determined by using the measurement method as defined in DIN EN 1849-2 standard of at least 0.1 mm, more preferably at least 0.2 mm, even more preferably at least 0.3 m, still more preferably at least 0.4 mm, particularly at least 0.5 mm.

According to one or more embodiments, the waterproofing layer has a thickness determined by using the measurement method as defined in DIN EN 1849-2 standard of 0.1 - 5.0 mm, preferably 0.25 - 3.5 mm, more preferably 0.35 - 3.0 mm, even more preferably 0.45 - 2.5 mm, still more preferably 0.5 - 2.0 mm. It can be advantageous that the sealing device further comprises a top-coating applied on at least portion of the first major surface of the waterproofing layer. The top-coating may comprise UV-absorbers and/or thermal stabilizers to protect the waterproofing layer from damaging influence of sunlight. The top coating may also comprise color pigments in order to provide the waterproofing layer with a desired color.

The sealing device may further comprise a reinforcing layer, which is fully embedded into the waterproofing layer. It may, however, be also possible or even preferred that the sealing device does not contain any reinforcing layers, which are fully embedded into the waterproofing layer. By the expression “fully embedded” is understood to mean that the reinforcing layer is fully covered by the matrix of the waterproofing layer.

The type of the reinforcing layer, if used, is not particularly restricted. For example, the reinforcing layers commonly used for improving the dimensional stability of single-ply roofing membranes are suitable. Preferred reinforcing layers include non-woven fabrics, woven fabrics, and laid scrims, and combinations thereof.

The term “laid scrim” refers in the present disclosure web-like non-woven products composed of at least two sets of parallel yarns (also designated as weft and warp yarns), which lay on top of each other and are chemically bonded to each other. The yarns of a non-woven scrim are typically arranged with an angle of 60 - 120°, such as 90 ± 5°, towards each other thereby forming interstices, wherein the interstices occupy more than 60% of the entire surface of the laid scrim. Typical materials for laid scrims include metal fibers, inorganic fibers, particularly glass fibers, and synthetic organic fibers, in particular polyester, polypropylene, polyethylene, and polyethylene terephthalate (PET).

According to one or more embodiments, the reinforcing layer is composed of synthetic organic fibers, preferably selected from the group consisting of polyester fibers, polypropylene fibers, polyethylene fibers, nylon fibers, and polyamide fibers. According to one or more further embodiments, the reinforcing layer is composed of inorganic fibers, preferably selected from the group consisting of glass fibers, aramid fibers, wollastonite fibers, and carbon fibers, more preferably glass fibers.

According to one or more further embodiments, the sealing device further comprises a second waterproofing layer comprising at least one thermoplastic polymer P3 and having first and second major surfaces, wherein the second major surface of the second waterproofing layer is directly or indirectly connected to at least a portion of the first major surface of the waterproofing layer.

The at least one thermoplastic polymer P3 is preferably selected from the group consisting of ethylene - vinyl acetate copolymer, ethylene - acrylic ester copolymers, ethylene - a-olefin copolymers, ethylene homopolymers, propylene-ethylene copolymers, propylene - a-olefin copolymers, propylene homopolymers, polyvinylchloride, polyethylene terephthalate, polystyrene, polyamides, chlorosulfonated polyethylene, ethylene propylene diene rubber, and polyisobutylene. According to one or more embodiment, the at least one thermoplastic polymer P3 is selected from the group consisting of polyethylene, ethylene copolymers, copolymers of ethylene with vinyl acetate, polypropylene, and propylene copolymers.

The amount of the at least one thermoplastic polymer P3 in the second waterproofing layer is not particularly restricted. Preferably, the at least one thermoplastic polymer P3 comprises at least 35 wt.-%, more preferably at least 45 wt.-%, even more preferably at least 55 wt.-%, of the total weight of the second waterproofing layer. According to one or more embodiments, the second waterproofing layer comprises, as polymer basis, 35 - 95 wt.-%, preferably 45 - 90 wt.-%, more preferably 55 - 85 wt.-%, of the at least one thermoplastic polymer P3. The polymer basis of the second waterproofing layer may comprise, in addition to the at least one thermoplastic polymer P3, other polymers or copolymers which are not allocated to the category of thermoplastic polymer P3.

The second waterproofing layer can comprise, in addition to the at least one thermoplastic polymer P3, auxiliary components, for example, UV- and heat stabilizers, antioxidants, plasticizers, flame retardants, fillers, dyes, pigments such as titanium dioxide and carbon black, matting agents, antistatic agents, impact modifiers, biocides, and processing aids such as lubricants, slip agents, antiblock agents, and denest aids. The total amount of these auxiliary components is preferably not more than 65 wt.-%, more preferably not more than 55 wt.-%, even more preferably not more than 45 wt.-%, still more preferably not more than 35 wt.-%, based on the total weight of the second waterproofing layer.

The preferences given above for the waterproofing layer, the layer of non- woven fabric, the second waterproofing layer, and to the thermoplastic polymers P1, P2, and P3 apply equally to all aspects of the present invention unless otherwise stated.

Another subject of the present invention is a method for producing a sealing device (1) having at least one heat-weldable short edge, the method comprising steps of: a) Providing a membrane having two primary exterior surfaces and a transverse width (W) defined by long edges (e1, e2), the membrane comprising a waterproofing layer (2) having a first major surface and a second major surface separated from the first major surface by a thickness and a layer of non-woven fabric (3) comprising at least one thermoplastic polymer P2 and covering at least a portion of the second major surface of the waterproofing layer (2), b) Cutting the membrane into a length (L) defined by first and second short edges (e3, e4), c) Subjecting the membrane to a heat-treatment step comprising heating at least part of the fibers contained in a first and/or a second short edge portion (4, 5) of the non-woven fabric layer (3) to a temperature above the melting of the at least one thermoplastic polymer P2 followed by subsequent cooling of said heated fibers, wherein the first and second short edge portions (4, 5) extend along the short edges (e3, e4) of the membrane, and d) Optionally winding the heat-treated membrane obtained from step b) or c) into a roll.

According to one or more embodiments, step c) of the method is conducted in such a manner that the capillarity for water of the layer of non-woven fabric (2) in the area of the first and/or second short edge portion (4, 5) is reduced to a value, which is lower than the capillarity for water of the layer of non-woven fabric (3) in a center portion (6) extending between the first and second short edge portions (4, 5).

According to one or more embodiments, step c) of the method is conducted in such a manner that the capillarity for water of the layer of non-woven fabric (2) in the area of the first and/or second short edge portion (4, 5) is reduced to a value, which is at least 10%, preferably at least 20%, more preferably at least 25%, even more preferably at least 30%, still more preferably at least 35%, such as at least 40%, most preferably at least 45%, lower than the capillarity for water of the layer of non-woven fabric (3) in a center portion (6) extending between the first and second short edge portions (4, 5).

Step c) of the method can be conducted before, during, or after step b). In case step c) is conducted before the membrane has been cut into the length (L), the heat-treatment is conducted on the surface area(s) of the layer of non-woven fabric (3), which after the cutting step constitute(s) the first and second short edge portions (4, 5) of the non-woven fabric (3). According to one or more embodiments, step c) of the method is conducted before step b) or simultaneously with step b), preferably simultaneously with step b). In step c), at least part of the fibers contained in the in the first and/or a second short edge portion (4, 5) of the non-woven fabric layer (3) are heated to a temperature above the melting point of the at least one thermoplastic polymer P2 followed by subsequent cooling of said heated fibers. The temperature to which the fibers are heated in step c) depends on the embodiment of the sealing device, in particular of the composition of the fibers. It may be preferable that the fibers are heated to a temperature in the range of 100 - 400°C, preferably 125 - 350°C, more preferably 150 - 300°C. In the subsequent cooling step, the heated fibers are cooled, preferably to a temperature below the melting point of the at least one thermoplastic polymer P2, more preferably to a temperature of below 60°C, even more preferably of below 40°C.

The heating of the fibers can be conducted using any conventional means, such as by using a hot-air dryer or contact heating means, such as a hot-press or heating rolls.

According to one or more embodiments, the membrane is wound into a winding step d) in a roll after it has been subjected to the heat-treatment step c). Depending on the order of steps b) and c), the membrane that is wound in a roll in step d) can be the membrane obtained from step b) or from step c).

The further details of the method for producing the sealing device depend on the embodiment of the sealing device. According to one or more embodiments, step a) comprises steps of: a1) Extruding a composition of the waterproofing layer (2) through an extruder die and a2) Thermally laminating or adhesively bonding the layer of non-woven fabric (3) onto the second major surface of the waterproofing layer (2) in a manner that gives direct or indirect bonding between the layer of non-woven fabric (3) and waterproofing layer (2).

In the extrusion step a1), the composition of the waterproofing layer is first melt-processed in an extruder to produce a homogenized melt, which is then extruded through the extruder die. Suitable extrusion apparatuses comprising at least one extruder and an extruder die are well known to a person skilled in the art. Any conventional extruders, for example, a ram extruder, single screw extruder, a twin-screw extruder, or a planetary roller extruder may be used. Preferably, the extruder is a screw extruder, more preferably a twin- screw extruder.

Preferably, the layer of non-woven fabric has a mass per unit weight of at least 25 g/m 2 , more preferably at least 35 g/m 2 , still more preferably at least 55 g/m 2 , such as at least 75 g/m 2 . According to one or more embodiments, the layer of non-woven fabric has a mass per unit weight of 25 - 500 g/m 2 , preferably 35 - 400 g/m 2 , more preferably 55 - 350 g/m 2 , even more preferably 75 - 350 g/m 2 , still more preferably 95 - 300 g/m 2 .

Another subject of the present invention is a roofing or waterproofing membrane obtained by using the method for producing a sealing device of the present invention.

Another subject of the present invention is a method for covering a substrate, the method comprising steps of:

I) Applying a first sealing device (1 ) according to the present invention on the surface of the substrate such that the layer of non-woven fabric (3) is facing the surface of the substrate, II) Applying a second sealing device (1’) according to the present invention on the surface of the substrate such that the layer of non-woven fabric (3’) is facing the surface of the substrate, III) Overlapping a short edge region of the second sealing device (1’) over a short edge section of an upper side of the first sealing device (1),

IV) Bonding the opposing surfaces of the short edge region and the overlapped short edge section to each other by using heat-welding means.

In case the first and second sealing devices (1, 1’) are provided in form of rolls, steps I) and II) are preceded by steps of unrolling the sealing devices.

According to one or more embodiments, step IV) of the method comprises:

IV’) Heating the short edge region of the second sealing device and the overlapped short edge section of the first sealing device above the melting temperature of the at least one thermoplastic polymer P1 and IV”) Bonding the opposing surfaces of the short edge region and the overlapped short edge section to each other under sufficient pressure to provide acceptable seam strength without use of an adhesive.

Steps IV’) and IV”) of the method can be conducted manually, for example by using a hot air tool, or by using an automatic welding device, such as an automatic hot-air welding device, for example Sarnamatic® 661 welding device. The temperature to which the short edge region of the second sealing device and the overlapped short edge section of the first sealing device are heated depends on the embodiment of the first and second sealing devices and also whether the steps IV’) and IV”) are conducted manually or by using an automatic welding device. Preferably, the short edge region of the second sealing device and the overlapped short edge section of the first sealing device are heated to a temperature of at or above 150°C, more preferably at or above 200°C, even more preferably of above 250°C.

According to one or more embodiments, the substrate that is covered with the sealing devices is a roof substrate, preferably an insulation board, a cover board, and an existing roofing membrane.

According to one or more embodiments, the overlapped short edge section extends over the whole width (W1 ) of the waterproofing layer (2) of the first sealing device (1 ) and the short edge region extends over the whole width (W1’) of the waterproofing layer (2’) of the second sealing device (1’).

According to one or more embodiments, the width of the overlapped short edge section measured in the longitudinal direction of the first sealing device (1 ) does not exceed the width of the second short edge portion (5’) of the layer of non-woven fabric (3’) measured in longitudinal direction of the second sealing device (1’).

According to one or more embodiments, the second sealing device (1’) is overlapped by the width of its second short edge portion (5’) over the upper side of the first sealing device (1 ) as shown in Figure 4. In these embodiments, the width of the overlapped short edge section measured in the longitudinal direction of the first sealing device (1) corresponds to to the width of the second short edge portion (5’) of the layer of non-woven fabric (3’) measured in longitudinal direction of the second sealing device (1’).

Still another subject of the present invention is a waterproofed structure obtained by using the method for covering a substrate according to the present invention.

According to one or more embodiments, the substrate is a roof substrate, preferably an insulation board, a cover board, and an existing roofing membrane. Examples Preparation of sealing devices

Exemplary sealing devices were composed of a commercially available single- ply waterproofing membrane (Sarnafil AT-15 FSA P) and a layer of non-woven polypropylene fabric layer (HyJet from RKW SE, Germany), which had been thermally laminated on the top surface of the waterproofing membrane. The waterproofing membrane had a thickness of 1.5 mm and the fleece had a mass per unit area of ca. 30 g/m 2

Before the fleece layer was adhered onto the top surface of the waterproofing membrane, it was thermally treated by heat-welding the layer against a Teflon film using a Sarnamatic 660 hot-air welding apparatus and a welding speed of 3m/min. The heat welding with the Teflon film was conducted using different air temperatures and the capillarity for water of the thermally treated non-woven fabric layers of the sealing devices were measured according to the procedure as described below.

Capillarity for water

The capillarity for water of the thermally treated fleece layers of the sealing devices was determined by using the following procedure.

In the measurement, rectangular samples having dimensions of 220 x 150 mm (height x width) were first cut from each of the sealing devices prepared according to the procedure as described above. The samples were hanged in a vertical position such that the bottom edge of the sample was immersed in water containing a blue coloring agent (methylene blue, 0.5 g/l). Each sample was held in place for 24 hours with a 20 mm height of the sample immersed in the colored water at a temperature of 23°C. The height to which the colored water had risen during the measurement was recorded as a representative value for the capillarity for water of the tested fleece layer. The results of the capillarity for water measurements and the temperature of the air used in the heat treatment step are presented in Table 1 . Welded seam strength

Two sealing devices overlapped along their short edges were heat-welded to each other using the a Sarnamatic 660 welding apparatus using an air temperature of 400°C and welding speed of 3m/min. The welded seam strength was evaluated on scale of 1 to 5, wherein 1 designates a failure in the welded seam area and 5 designates a failure outside the seam area. The values of the welded seam strength obtained with inventive and reference sealing devices are presented in Table 1. Table 1