EP4594574A1

EP4594574A1 - Sealing element with improved impact resistance

Info

Publication number: EP4594574A1
Application number: EP22959734.9A
Authority: EP
Inventors: Robin BARMET; Wilfried Carl; Matthias VILLIGER; Qin WEI; Shenghua XU
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2022-09-26
Filing date: 2022-09-26
Publication date: 2025-08-06
Also published as: WO2024065082A1

Abstract

The invention is directed to a sealing element (1) comprising a waterproofing layer (2) comprising polyvinylchloride, at least one plasticizer, optionally at least one inorganic pigment, and at least one polyhydroxyalkanoate. The invention is also directed to use of polyhydroxyalkanoate for improving impact resistance of a plasticized polyvinylchloride formulation.

Description

SEALING ELEMENT WITH IMPROVED IMPACT RESISTANCE

Technical field

The invention relates to the field of waterproofing of building constructions by using sealing devices comprising a waterproofing layer. Particularly, the invention relates to roofing membranes comprising a waterproofing layer based on plasticized polyvinylchloride having an improved impact resistance.

Background of the invention

In the field of construction polymeric sheets, which are often referred to as membranes, panels, or sheets, 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 concrete structures due to building settlement, load deflection, or concrete shrinkage. Roofing membranes used for waterproofing of flat and low-sloped roof structures are typically provided as single-ply or multi-ply membrane systems. In a single-ply system, the roof substrate is covered using a roofing membrane composed of a single waterproofing layer. In multi-ply membrane systems, roofing membranes comprising multiple waterproofing layers having similar or different composition are used. 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 the 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 roofing membrane is adhered may be comprised of variety of materials. The substrate may, for example, be a concrete, metal, or wood deck, or it may include an insulation board or recover board and/or an existing membrane.
One important performance features of a roofing membrane is the resistance against mechanical impacts, which defines the hail resistance of the membrane. Due to climate change, in many regions the severity and frequency of hail events are expected to increase. It would thus be highly desirable to provide a roofing membrane with increased resistance against hail impacts.
There is a very limited number of known ways to improve the impact resistance of a roofing membrane made of plasticized PVC, except for increasing the thickness of the membrane and/or using a stronger reinforcement layer. Increased thickness, however, also comes along with higher costs as well as increased weight and stiffness of the membrane. Use of a stronger (tighter) fiber-based reinforcement layer, on the other hand, cannot fully avoid loss of water tightness resulting a breach in the polymeric layers of the membrane.
Toughening agents that are typically used for improving the impact resistance of unplasticized PVC and other plastics, such as acrylic rubber-based core shell impact modifiers or soft blend components such as ketone ethylene ester terpolymers (KEE) , are not suitable for plasticized PVC. Reason for this is that impact toughening is based on a mechanism, where stresses caused by impact are transferred from a stiff and brittle matrix into a soft embedded particle resulting in a dissipation of strain energy. In case the matrix is already soft, like in plasticized PVC, no stress transfer will take place.
Furthermore, in view of current and future sustainability requirements, it would also be highly desirable to reduce the CO ₂ footprint of a roofing membrane by replacing the petroleum based raw materials, i.e., plastics, with renewable raw materials. Generally, there are quite many ongoing research activities focused on providing more ecologically sustainable plastic products and some progress has already been made. However, up to now, all renewable blend components, such as bio-based plasticizers have the disadvantage of being bio-degradable, which makes them unsuitable for use in products designed for long-term outdoor exposure, such as roofing membranes. Finally, increasing the amount of oligomeric plasticizers in roofing membrane, even if bio-based, is generally not preferred since these types of compounds tend to migrated from the membrane material resulting in well-known disadvantageous effects.
There is thus a need for a new type of sealing element, particularly a roofing membrane, based on plasticized PVC and having an improved impact resistance and a decreased CO ₂ footprint compared to sealing elements of prior art.
Summary of the invention
The object of the present invention is to provide a sealing element, particularly a roofing membrane, having an improved impact resistance and preferably a decreased CO ₂ footprint compared to the sealing elements of prior art.
Surprisingly, it has been found that the features of claim 1 achieve this object.
Particularly, it was surprisingly found out that the impact strength of a plasticized PVC formulation can be significantly improved by adding moderate amounts one or more polyhydroxyalkanoates as blend components to the formulation. Such plasticized PVC formulations are especially suitable for use in providing of sealing elements, such as roofing membranes, that due to their application environment are prone to mechanical damages cause by, for example, hailstorms. The use of polyhydroxyalkanoates as a blend component also enables decreasing the CO ₂ footprint since these compounds can be produced by using biological organisms, such as Gram-negative and Gram-positive bacteria (fermentation under limitation of nutrients) or algae.
Thus, the core of the present invention is related to a sealing element comprising a waterproofing layer comprising:
a) 25 –65 wt. -%of a polyvinylchloride resin,
b) 15 –50 wt. -%of at least one plasticizer, and
c) 0 –15 wt. -%of at least one inorganic pigment, all proportions being based on the total weight of the waterproofing layer,
wherein the waterproofing layer further comprises:
d) At least one polyhydroxyalkanoate.
Additional aspects of the present invention are presented in further independent claims. Particularly preferred embodiments are outlined throughout the description and the dependent claims.

Brief description of the Drawings

Fig. 1 shows a cross-section of a sealing element (1) comprising a waterproofing layer (2) and a layer of fiber material (3) fully embedded into the waterproofing layer (3) .
Fig. 2 shows a cross-section of a sealing element (1) comprising a waterproofing layer (2) and a second waterproofing layer (4) adhered to the upper major surface of the waterproofing layer (4) .

Detailed description of the invention

A first aspect of the present invention is directed to a sealing element comprising a waterproofing layer comprising:
a) 25 –65 wt. -%of a polyvinylchloride resin,
b) 15 –50 wt. -%of at least one plasticizer, and
c) 0 –15 wt. -%of at least one inorganic pigment, all proportions being based on the total weight of the waterproofing layer,
wherein the waterproofing layer further comprises:
d) At least one polyhydroxyalkanoate.
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 “amount or content of at least one component X” in a composition, for example “the amount of the at least one plasticizer” refers to the sum of the individual amounts of all plasticizers contained in the composition. Furthermore, in case the composition comprises 20 wt. -%of the at least one plasticizer, the sum of the amounts of all plasticizers contained in the composition equals 20 wt. -%.
The term “room temperature” designates a temperature of 23 ℃.
The waterproofing layer is preferably a sheet-like element having upper and lower major surfaces, i.e., top and bottom surfaces. The term “sheet-like element” refers in the present document to elements having a length and width at least 25 times, preferably at least 50 times, more preferably at least 150 times greater than the thickness of the element.
Preferably, the sealing element is selected from a roofing membrane, a waterproofing membrane, and a tape, preferably from a roofing membrane and a waterproofing membrane. According to one or more embodiments, the sealing membrane is a roofing membrane.
The term “roofing membrane” refers in the present disclosure to the conventional meaning of the term roofing membrane, i.e., a membrane that is a water impermeable sheet of polymeric material that is use for covering an outer surface of a roof deck. Roofing membranes and method for their production are known to a person skilled in the art.
According to the invention, the waterproofing layer comprises:
a) 25 –65 wt. -%, preferably 30 –60 wt. -%of a polyvinylchloride resin,
b) 15 –50 wt. -%, preferably 20 –40 wt. -%of at least one plasticizer,
c) 0 –15 wt. -%, preferably 0 – 12.5 wt. -%of at least one mineral filler, and
d) At least one polyhydroxyalkanoate, all proportions being based on the total weight of the waterproofing layer.
Preferably, polyvinylchloride resin has a K-value determined by using the method as described in ISO 1628-2-1998 standard in the range of 50 –85, more preferably 65 –75. The K-value is a measure of the polymerization grade of the PVC-resin and it is determined from the viscosity values of the PVC homopolymer as virgin resin, dissolved in cyclohexanone at 30℃.
The type of the at least one plasticizer is not particularly restricted in the present invention. Suitable plasticizers for the PVC-resin include but are not restricted to, for example, linear or branched phthalates such as di-isononyl phthalate (DINP) , di-nonyl phthalate (L9P) , diallyl phthalate (DAP) , di-2-ethylhexyl-phthalate (DEHP) , dioctyl phthalate (DOP) , diisodecyl phthalate (DIDP) , and mixed linear phthalates (911P) . Other suitable plasticizers include phthalate-free plasticizers, such as trimellitate plasticizers, adipic polyesters, and biochemical plasticizers. Examples of biochemical plasticizers include epoxidized vegetable oils, for example, epoxidized soybean oil and epoxidized linseed oil and acetylated waxes and oils derived from plants, for example, acetylated castor wax and acetylated castor oil.
Particularly suitable phthalate-free plasticizers to be used in the waterproofing layer include alkyl esters of benzoic acid, dialkyl esters of aliphatic dicarboxylic acids, polyesters of aliphatic dicarboxylic acids or of aliphatic di-, tri-and tetrols, the end groups of which are unesterified or have been esterified with monofunctional reagents, trialkyl esters of citric acid, acetylated trialkyl esters of citric acid, glycerol esters, benzoic diesters of mono-, di-, tri-, or polyalkylene glycols, trimethylolpropane esters, dialkyl esters of cyclohexanedicarboxylic acids, dialkyl esters of terephthalic acid, trialkyl esters of trimellitic acid, triaryl esters of phosphoric acid, diaryl alkyl esters of phosphoric acid, trialkyl esters of phosphoric acid, and aryl esters of alkanesulphonic acids.
According to one or more embodiments, the at least one plasticizer is selected from the group consisting of phthalates, trimellitate plasticizers, adipic polyesters, and biochemical plasticizers.
The waterproofing layer further comprises at least one polyhydroxyalkanoate.
Suitable polyhydroxybutyrates (PHA) for use in the waterproofing layer include, but are not limited to, polyhydroxybutyrate (PHB) , polyhydroxyvalerate (PHV) , polyhydroxybutyrate-covalerate (PHB/V) , and polyhydroxyhexanoate (PHH) .
According to one or more embodiments, the at least one polyhydroxyalkanoate comprises at least one polyhydroxybutyrate, preferably a polyhydroxy butyrate homopolymer.
In the present disclosure, the term “polyhydroxybutyrate” (PHB) is understood to include both [beta] -and [gamma] -PHB as well as their copolymers.
Generally, the expression “the at least one component X comprises at least one component XN” , such as “the at least one polyhydroxyalkanoate comprises at least one polyhydroxybutyrate” is understood to mean in the context of the present disclosure that the waterproofing layer comprises one or more polyhydroxybutyrates as representatives of the at least one polyhydroxyalkanoate.
Polyhydroxybutyrates were surprisingly found to be especially suitable for improving the impact resistance of a waterproofing layer based on a plasticized PVC formulation.
As a polyester, polyhydroxybutyrate it is well miscible with polar PVC. Another advantage is that polyhydroxybutyrate has a high molecular weight, which significantly decreases its migration rate from the PVC matrix of the waterproofing layer.
Furthermore, it has been found out that the biodegradability resulting from the oxygen content is of minor importance since, as a blend component, the polyhydroxybutyrate molecules are fully embedded in the PVC matrix and thus not exposed to degrading microbial organisms. This is in contrast to bio-based plasticizers, which are known to be degraded after having been migrated to the surface of a PVC membrane and fully exposed to environmental impacts.
According to one or more embodiments, the at least one polyhydroxyalkanoate is a polyhydroxybutyrate, preferably a polyhydroxy butyrate homopolymer.
Preferably, the waterproofing layer comprises at least 1.5 wt. -%, preferably at least 5 wt .-%, based on the total weight of the waterproofing layer, of the at least one polyhydroxyalkanoate.
According to one or more embodiments, the waterproofing layer comprises 5 –55 wt .-%, preferably 7.5 –50 wt. -%, more preferably 10 –45 wt. -%, based on the total weight of the waterproofing layer, of the at least one polyhydroxyalkanoate.
The waterproofing layer may further comprise at least one inorganic pigment.
Suitable inorganic pigments for use in the waterproofing layer include, for example, titanium dioxide, zinc oxide, zinc sulfide, barium sulphate, iron oxide, mixed metal iron oxide, and aluminium powder.
Preferably, the at least one inorganic pigment has a has a median particle size d ₅₀ of not more than 1000 nm, more preferably not more than 750 μm, even more preferably not more than 500 nm. According to one or more embodiments, the at least one inorganic pigment has a has a median particle size d ₅₀ in the range of 50 –1000 nm, preferably 75 –750 nm, more preferably 100 –650 nm, even more preferably 125 –500 μm, still more preferably 150 –350 μm, most preferably 200 –300 nm.
According to one or more embodiments, the at least one inorganic pigment is titanium dioxide.
According to one or more embodiments, the at least one inorganic pigment is present in the waterproofing layer in an amount of 1.5 -15 wt. -%, preferably 2.5 –15 wt. -%, more preferably 3.5 –12.5 wt. -%, even more preferably 5 –12.5 wt. -%, based on the total weight of the waterproofing layer.
The waterproofing layer can further comprise one or more additives, for example, UV-and heat stabilizers, antioxidants, flame retardants, dyes, carbon black, matting agents, antistatic agents, impact modifiers, biocides, and processing aids such as lubricants, slip agents, antiblock agents, and denest aids.
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 0.5 –5.0 mm, preferably 0.7 –3.5 mm, more preferably 1 –3 mm, most preferably 1 –2.5 mm.
According to one or more embodiments, the sealing element further comprises a layer of fiber material, which is fully embedded into the waterproofing layer or adhered to a lower major surface of the waterproofing layer. By the expression “fully embedded” is meant that the layer of fiber material layer is fully covered by the matrix of the waterproofing layer.
The layer of fiber material may be used to ensure the mechanical stability of the waterproofing layer when exposed to varying environmental conditions, in particular to large temperature fluctuations.
The term “fiber material” designates in the present document materials composed of fibers comprising or consisting of, for example, organic, inorganic or synthetic organic materials. Examples of organic fibers include, for example, cellulose fibers, cotton fibers, and protein fibers. Particularly suitable synthetic organic materials include, for example, polyester, homopolymers and copolymers of ethylene and/or propylene, viscose, nylon, and polyamides. Fiber materials composed of inorganic fibers are also suitable, in particular, those composed of metal fibers or mineral fibers, such as glass fibers, aramid fibers, wollastonite fibers, and carbon fibers. Inorganic fibers, which have been surface treated, for example, with silanes, may also be suitable. The fiber material can comprise short fibers, long fibers, spun fibers (yarns) , or filaments. The fibers can be aligned or drawn fibers. It may also be advantageous that the fiber material is composed of different types of fibers, both in terms of geometry and composition.
Preferably, the layer of fiber material is selected from the group consisting of non-woven fabrics, woven fabrics, and non-woven scrims.
The term “non-woven fabric” designates in the present document 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 nonwoven fabric. In chemical bonding, chemical binders such as adhesive materials are used to hold the fibers together in a non-woven fabric.
The term “non-woven scrim” designates in the present document web-like non-woven products composed of yarns, which lay on top of each other and are chemically bonded to each other. Typical materials for non-woven scrims include metals, fiberglass, and plastics, in particular polyester, polypropylene, polyethylene, and polyethylene terephthalate (PET) .
According to one or more embodiments, the layer of fiber material is a non-woven fabric, preferably a non-woven fabric having a mass per unit weight of not more than 300 g/m ², preferably not more than 250 g/m ². According one or more embodiments, the layer of fiber material is a non-woven fabric having a mass per unit weight of 15 –300 g/m ², preferably 25 –250 g/m ², more preferably 35 –200 g/m ², most preferably 45 –150 g/m ².
Preferably, the non-woven fabric of the layer of fiber material comprises synthetic organic and/or inorganic fibers. Particularly suitable synthetic organic fibers for the non-woven fabric include, for example, polyester fibers, polypropylene fibers, polyethylene fibers, nylon fibers, and polyamide fibers. Particularly suitable inorganic fibers for the non-woven fabric include, for example, glass fibers, aramid fibers, wollastonite fibers, and carbon fibers.
According to one or more embodiments, the non-woven fabric of the layer of fiber material has as the main fiber component 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 non-woven fabric of the layer of fiber material has as the main fiber component inorganic fibers, preferably selected from the group consisting of glass fibers, aramid fibers, wollastonite fibers, and carbon fibers, more preferably glass fibers.
The sealing element of the present invention may be a single-or a multi-ply roofing membrane. The term “single-ply roofing membrane” designates in the present document membranes comprising one single waterproofing layer whereas the term “multi-ply roofing membrane” designates membranes comprising more than one waterproofing layers. In case of a multi-ply roofing membrane, the waterproofing layers may have similar or different compositions.
Single-and multi-ply membranes are known to a person skilled in the art and they may be produced by any conventional means, such as by way of extrusion or co-extrusion, calendaring, or by spread coating. According to one or more embodiments, the roofing membrane is a single-ply membrane comprising exactly one waterproofing layer, as shown in Figure 1.
According to one or more further embodiments, the sealing element is a multi-ply membrane comprising at least two waterproofing layers, preferably exactly two waterproofing layers, as shown in Figure 2. In these embodiments, the roofing membrane further comprises a second waterproofing layer having lower and upper major surfaces, wherein the lower major surface of the second waterproofing layer is directly or indirectly bonded to at least portion of the upper major surface of the waterproofing layer.
According to one or more embodiments, the second waterproofing layer is a polyvinylchloride-based waterproofing layer. Preferably, the second waterproofing layer has substantially similar composition as the waterproofing layer. The second waterproofing layer may further comprise a layer of fiber material, which is fully embedded into the second waterproofing layer. It may, however, be also possible or even preferred that the second waterproofing layer does not contain a layer of fiber material.
The sealing element of the present invention is typically provided in a form of a prefabricated membrane article, which is delivered to the construction site and unwound from rolls to provide sheets having a width of 1 –5 m and length of several times the width. However, the sealing element can also be used in the form of strips having a width of typically 1 –20 cm, for example so as to seal joints between two adjacent membranes. Moreover, the sealing element can also be provided in the form of planar bodies, which are used for repairing damaged locations in existing adhered waterproofing, roofing, or facade systems.
Another aspect of the present invention is use of polyhydroxyalkanoate to increase impact resistance of a plasticized polyvinylchloride formulation comprising:
a) 25 –65 wt. -%of a polyvinylchloride resin,
b) 15 –50 wt. -%of at least one plasticizer, and
0 –15 wt. -%of at least one inorganic pigment, all proportions being based on the total weight of the plasticized polyvinylchloride formulation,
wherein the impact resistance is measured according to EN 12691, Method A, standard.
According to the invention, the plasticized polyvinylchloride formulation comprises:
a) 25 –65 wt. -%, preferably 30 –60 wt. -%of a polyvinylchloride resin,
b) 15 –50 wt. -%, preferably 20 –40 wt. -%of at least one plasticizer, and
c) 0 –15 wt. -%, preferably 0 – 12.5 wt. -%of at least one mineral filler, all proportions being based on the total weight of the plasticized polyvinylchloride formulation.
Preferences given above for the polyvinylchloride resin, the at least one plasticizer, and to at least one inorganic pigment contained in the waterproofing layer are also applicable for the plasticized polyvinylchloride formulation.
According to one or more embodiments, the at least one polyhydroxyalkanoate comprises at least one polyhydroxybutyrate, preferably a polyhydroxy butyrate homopolymer.
According to one or more embodiments, the at least one polyhydroxyalkanoate is a polyhydroxybutyrate, preferably a polyhydroxy butyrate homopolymer.
Preferably, the plasticized polyvinylchloride formulation comprises at least 1.5 wt. -%, preferably at least 5 wt. -%, based on the total weight of the plasticized polyvinylchloride formulation, of the at least one polyhydroxyalkanoate.
According to one or more embodiments, the plasticized polyvinylchloride formulation comprises 5 –55 wt. -%, preferably 7.5 –50 wt. -%, more preferably 10 –45 wt. -%, based on the total weight of the plasticized polyvinylchloride formulation, of the at least one polyhydroxyalkanoate.
According to one or more embodiments, the at least one inorganic pigment is present in the plasticized polyvinylchloride formulation in an amount of 1.5 -15 wt. -%, preferably 2.5 –10 wt. -%, based on the total weight of the plasticized polyvinylchloride formulation.
The plasticized polyvinylchloride formulation can further comprise one or more additives, for example, UV-and heat stabilizers, antioxidants, flame retardants, 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.
Examples
The followings materials shown in Table 1 were used in providing the polymer formulations.
Table 1
Preparation of sealing elements
The polymer compositions were melt-processed in a two roll mill and then pressed into sheets having a thickness of 2.0 mm, using a laboratory curing press at a temperature of 190 ℃ and using a pressing time of 3 minutes at 120 bar.
Mechanical properties
Tensile strength and elongation at break were measured according to ISO 527-3: 2018 standard at a temperature of 21 ℃ using a Zwick tensile tester and a cross head speed of 100 mm/min. Impact resistance was measured according to EN 12691, Method A, standard using pre-cut samples having a trapezoidal shape under identical conditions.
The tested polymer compositions and the measured mechanical properties as shown in Table 2.

Claims

A sealing element (1) comprising a waterproofing layer (2) comprising:

a) 25 –65 wt. -%of a polyvinylchloride resin,

b) 15 –50 wt. -%of at least one plasticizer, and

c) 0 –15 wt. -%of at least one inorganic pigment, all proportions being based on the total weight of the waterproofing layer (2) ,

wherein the waterproofing layer (2) further comprises:

d) At least one polyhydroxyalkanoate.
The sealing element according to claim 1, wherein the sealing element is a roofing membrane.
The sealing element according any one of previous claims, wherein the at least one polyhydroxyalkanoate comprises at least one polyhydroxybutyrate, preferably a polyhydroxy butyrate homopolymer.
The sealing element according to any one of previous claims, wherein the waterproofing layer (2) comprises at least 1.5 wt. -%, preferably at least 5 wt. -%, based on the total weight of the waterproofing layer (2) , of the at least one polyhydroxyalkanoate.
The sealing element according to any one of previous claims, wherein the waterproofing layer (2) comprises 5 –50 wt. -%, preferably 10 –45 wt. -%, based on the total weight of the waterproofing layer (2) , of the at least one polyhydroxyalkanoate.
The sealing element according to one of previous claims, wherein the at least one inorganic pigment is present in the waterproofing layer (2) in an amount of 1.5 -15 wt. -%, preferably 3.5 –12.5 wt. -%, based on the total weight of the waterproofing layer (2) .
The sealing element according to any 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 0.5 –5.0 mm, preferably 0.7 –2.5 mm.
The sealing element according to any of previous claims further comprising a layer of fiber material (3) fully embedded into the waterproofing layer (2) or adhered to a lower major surface of the waterproofing layer (2) .
The sealing element according to claim 8, wherein the layer of fiber material (3) is a non-woven fabric having a mass per unit area of 15 –300 g/m ², preferably 25 –250 g/m ².
The sealing element according to claim 8 or 9, wherein the non-woven fabric comprises synthetic organic fibers and/or inorganic fibers.
Use of polyhydroxyalkanoate to increase impact resistance of a plasticized polyvinylchloride formulation comprising:

a) 25 –65 wt. -%of a polyvinylchloride resin,

b) 15 –50 wt. -%of at least one plasticizer, and

0 –15 wt. -%of at least one inorganic pigment, all proportions being based on the total weight of the plasticized polyvinylchloride formulation,

wherein the impact resistance is measured according to EN 12691, Method A, standard.
Use according to claim 11, wherein the at least one polyhydroxyalkanoate comprises at least one polyhydroxy butyrate, preferably a polyhydroxy butyrate homopolymer.
Use according to claim 11 or 12, wherein the plasticized polyvinylchloride formulation comprises at least 1.5 wt. -%, preferably at least 5 wt. -%, based on the total weight of the plasticized polyvinylchloride formulation, of the at least one polyhydroxyalkanoate.
Use according to claim any one of claims 11-13, wherein the plasticized polyvinylchloride formulation comprises 5 –50 wt. -%, preferably 10 –45 wt. -%, based on the total weight of the plasticized polyvinylchloride formulation, of the at least one polyhydroxyalkanoate.
Use according to any one of claims 11-14, wherein the at least one inorganic pigment is present in the plasticized polyvinylchloride formulation in an amount of 1.5 -15 wt. -%, preferably 2.5 –10 wt. -%, based on the total weight of the plasticized polyvinylchloride formulation.