METHOD FOR SEALING ROOFING MEMBRANES

Abstract

A method for sealing adjacent roofing membranes of a hybrid roofing assembly. The method involves applying a sealing strip to establish a connection between the adjacent roofing membranes and creating a durable water tight seal at a joint between the adjacent roofing membranes, using a water impermeable liquid applied membrane. The method enables connecting in a water-tight fashion two incompatible roofing membranes using a water impermeable liquid applied membrane, thereby enabling the creation of hybrid roofs and reducing both repair and installation expenses.

Claims

1-15. (canceled)

16. A method for sealing adjacent roofing membranes, the method comprising the steps of: i. providing a roof assembly comprising a roof substrate, a first roofing membrane having a first upper surface and a first lower surface, and a second roofing membrane having a second upper surface and a second lower surface; ii. laying the first roofing membrane and the second roofing membrane onto a surface of the roof substrate in such a manner that an edge of the first roofing membrane is adjacent to an edge of the second roofing membrane, wherein the first roofing membrane is not in direct contact with the second roofing membrane, wherein the first lower surface and the second lower surface are in direct contact with the roof substrate; iii. applying a first polymer resin primer layer PR1 to at least a portion of the first upper surface and a second polymer resin primer layer PR2 to at least a portion of the second upper surface; iv. providing a sealing strip having an upper major surface and a lower major surface limited between short and long edges; V. adhesively bonding the sealing strip via the lower major surface to at least a portion of the first polymer resin primer layer PR1 and at least a portion of the second polymer resin primer layer PR2 so that a connection gets established between the first roofing membrane and the second roofing membrane; vi. applying a water impermeable liquid applied membrane M1 to the upper major surface of the sealing strip, optionally the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2; and vii. allowing the water impermeable liquid applied membrane M1 to cure in order to form a watertight seal between the first roofing membrane and the second roofing membrane.

17. The method according to claim 16, wherein the first roofing membrane comprises at least one polymer P1 selected from thermoplastic polyolefins (TPO) or a thermoplastic ethylene propylene diene terpolymer (EPDM).

18. The method according to claim 16, wherein the second roofing membrane comprises at least one polymer P2 selected from polyvinylchloride (PVC).

19. The method according to claim 16, wherein the first roofing membrane and the second roofing membranes have a thickness of 0.5-5 mm.

20. The method according to claim 16, wherein the first polymer resin primer layer PR1 is composed of a composition comprising synthetic rubber.

21. The method according to claim 16, wherein the second polymer resin primer layer PR2 is composed of a composition comprising: at least one liquid epoxy resin LER; and at least one amine hardener AH.

22. The method according to claim 16, wherein the sealing strip is a self-adhesive sealing strip.

23. The method according to claim 16, wherein the water impermeable liquid applied membrane M1 is applied to cover at least a portion of the first polymer resin primer layer PR1, at least a portion of the second polymer resin primer layer PR2 and the sealing strip.

24. The method according to claim 16, wherein the water impermeable liquid applied membrane M1 is applied by the application of a reactive composition RC1 in liquid form and letting the applied composition cure.

25. The method according to claim 24, wherein the reactive composition RC1 is selected from the list consisting of reactive one-part polyurethane compositions, reactive two-part polyurethane compositions and reactive two-part polyurea compositions.

26. The method according to claim 25, wherein the reactive composition RC1 has a water content of less than 10 wt.-%, based on the total weight of the composition.

27. The method according to claim 24, wherein the reactive composition RC1 is reactive one-part polyurethane composition containing: an amount of isocyanate-functional polymers in the range of 15 to 80 weight-% in relation to the total composition; an amount of latent hardener in the range of 0.5 to 25 weight-% in relation to the total composition; an amount of plasticizers in the range of 0 to 40 weight-% in relation to the total composition; and an amount of fillers in the range of 0 to 80 weight-% in relation to the total composition.

28. The method according to claim 16, wherein the water impermeable liquid applied membrane M1 comprise a fibre reinforcement mesh.

29. The method according to claim 16, wherein the first roofing membrane and the second roofing membrane are secured on the roofing substrate by adhesive and/or mechanically using screws, barbed plates or termination bars.

30. A roof system comprising, a roof substrate; a first roofing membrane having a first upper surface and a first lower surface, wherein a first polymer resin primer layer PR1 is applied to at least a portion of the first upper surface; a second roofing membrane having a second upper surface and a second lower surface, wherein a second polymer resin primer layer PR2 is applied to at least a portion of the second upper surface, wherein the first roofing membrane and the second roofing membrane are laid on a surface of the roof substrate so that an edge of the first roofing membrane is adjacent to an edge of the second roofing membrane, wherein the first lower surface and the second lower surface are in direct contact with the roof substrate, and wherein the first roofing membrane is not in direct contact with the second roofing membrane; a sealing strip having an upper major surface and a lower major surface limited between short and long edges, wherein the sealing strip is adhesively bonded via the lower major surface to at least a portion of the first polymer resin primer layer PR1 and at least a portion of the second polymer resin primer layer PR2 so that a connection gets established between the first roofing membrane and the second roofing membrane; and a water impermeable liquid applied membrane M1, wherein the water impermeable liquid applied membrane M1 is applied to the upper major surface of the sealing strip, optionally the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2, wherein the water impermeable liquid applied membrane M1 is allowed to cure in order to form a watertight seal between the first roofing membrane and the second roofing membrane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 shows a cross-section of a roof system comprising a roof substrate (1), a first roofing membrane (2), a second roofing membrane (3), a first polymer resin primer layer PR1 (4), a second polymer resin primer layer PR2 (5), a sealing strip (6), a termination bar (7) and a water impermeable liquid applied membrane M1 (8). Water impermeable liquid applied membrane M1 (8) creates a watertight seal at a joint (9) between the first roofing membrane (2) and the second roofing membrane (3).

DETAILED DESCRIPTION OF THE INVENTION

[0016] The subject of the present invention is a method for sealing adjacent roofing membranes, the method comprising the steps of: [0017] i. providing a roof assembly comprising a roof substrate, a first roofing membrane having a first upper surface and a first lower surface, and a second roofing membrane having a second upper surface and a second lower surface; [0018] ii. laying the first roofing membrane and the second roofing membrane onto a surface of the roof substrate in such a manner that an edge of the first roofing membrane is adjacent to an edge of the second roofing membrane, wherein the first roofing membrane is not in direct contact with the second roofing membrane, wherein the first lower surface and the second lower surface are in direct contact with the roof substrate; [0019] iii. applying a first polymer resin primer layer PR1 to at least a portion of the first upper surface and a second polymer resin primer layer PR2 to at least a portion of the second upper surface; [0020] iv. providing a sealing strip having an upper major surface and a lower major surface limited between short and long edges; [0021] v. adhesively bonding the sealing strip via the lower major surface to at least a portion of the first polymer resin primer layer PR1 and at least a portion of the second polymer resin primer layer PR2 so that a connection gets established between the first roofing membrane and the second roofing membrane; [0022] vi. applying a water impermeable liquid applied membrane M1 to the upper major surface of the sealing strip, optionally the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2; and [0023] vii. allowing the water impermeable liquid applied membrane M1 to cure in order to form a watertight seal between the first roofing membrane and the second roofing membrane.

[0024] 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.

[0025] 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.

[0026] The term elastomer refers to any natural, synthetic, or modified high molecular weight polymer or combination of polymers, which is capable of recovering from large deformations, i.e. has elastic properties. The elastomer can be, or already is, modified to a state in which it is essentially insoluble (but can swell) in a boiling solvent. The term elastomer may be used interchangeably with the term rubber.

[0027] The term molecular weight refers to 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.sub.n) of an oligomeric or polymeric mixture of molecules or moieties. The molecular weight may be determined by gel permeation chromatography (GPC) using polystyrene as standard, preferably using styrene-divinylbenzene gel with porosity of 100 Angstrom, 1000 Angstrom and 10000 Angstrom as columns and, depending on the molecule, tetrahydrofuran as a solvent, at 35 C., or 1,2,4-trichlorobenzene as a solvent, at 160 C.

[0028] The term melting temperature refers to a temperature at which a material undergoes transition from the solid to the liquid state. The melting temperature (T.sub.m) is preferably determined by differential scanning calorimetry (DSC) according to ISO 11357-3 standard using a heating rate of 2 C./min. The measurements can be performed with a Mettler Toledo DSC 3+ device and the T.sub.m 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.sub.m).

[0029] The term glass transition temperature (T.sub.g) refers to the temperature above which temperature a polymer component becomes soft and pliable, and below which it becomes hard and glassy. The glass transition temperature (T.sub.g) 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%.

[0030] The amount or content of at least one component X in a composition, for example the amount of the at least one acrylic polymer AP refers to the sum of the individual amounts of all acrylic polymers AP contained in the composition. Furthermore, in case the composition comprises 20 wt.-% of at least one acrylic polymer AP, the sum of the amounts of all acrylic polymers AP contained in the composition equals 20 wt.-%.

[0031] The term room temperature designates a temperature of 23 C.

[0032] The term planar element refers in the present document to sheet-like elements having a length and width at least 50 times, preferably at least 100 times, more preferably at least 250 times, greater than the thickness of the element.

[0033] In this document, the term polyurethane polymer includes all polymers prepared by the so-called diisocyanate polyaddition process. It includes isocyanate-functional polyurethane polymers obtained by reacting polyisocyanates and polyols, which may also be called prepolymers and are polyisocyanates themselves.

[0034] In this document, the term liquid-applied membrane refers to a material that is applied in liquid form as a layer onto a substrate and cured to form an elastic membrane, rendering the substrate waterproof.

[0035] The term primer refers in the present disclosure to a thin layer, typically thinner than 1 mm, particularly 1-200 m, preferably 1-100 m, of a solvent- or water-based composition, which is applied as a coating to a surface of a substrate, and which leads to an improvement in the adhesion of an adhesive to the surface of the substrate.

[0036] One of the advantages of the claimed method is that it enables connecting in a water-tight fashion two incompatible roofing membranes using a water impermeable liquid applied membrane. The claimed method facilitates the formation of hybrid roofs, reduces both repair and installation costs. More importantly, the claimed method of the present invention enables customers to use both PVC and non-PVC based roofing membrane within a single roofing system.

[0037] In step (i) a roof assembly is provided comprising a roof substrate, a first roofing membrane having a first upper surface and a first lower surface, and a second roofing membrane having a second upper surface and a second lower surface.

Roof Substrate:

[0038] A roof substrate refers to the underlying material or structural layer that serves as the base or foundation upon which roofing materials, coatings, or systems are applied or affixed. The roof substrate provides essential support, stability, and structural integrity to a roofing system.

[0039] The roofing systems may comprise further elements, such as films, membranes, or boards, such as vapor barriers, vapor breathers, insulation boards, or cover panels. A skilled person is familiar with these types of elements and knows where they are used in a roofing systems.

[0040] The roof substrate can be made from various materials, including but not limited to wood (such as plywood or oriented strand board), metal (such as steel or aluminum), concrete, or synthetic materials (such as insulation boards or composite panels). The roof substrate is preferably part of the roof of a building, especially a structural engineering and civil engineering building, preferably a house, an industrial building, a hangar, a shopping center, an athletic stadium or the like. The roof substrate is preferably part of a building, such as balcony, a terrace, a roof, particularly a flat or a slightly sloping roof, a roof garden, in the inner parts of a building of a floor, preferably a roof, particularly preferred a flat roof. Typically, the roof substrate is installed over primary structural components of the building, such as trusses, rafters, or a concrete deck.

[0041] Practice of the present invention is not necessarily limited by the selection of any particular roof substrate to which the membranes can be attached in forming the roofing systems of the present invention.

[0042] The roof substrate is preferably made of a material selected from the list consisting of: [0043] metals and alloys, such as aluminium, copper, iron, steel, nonferrous metals, including surface-finished metals and alloys, such as galvanized metals or chrome-plated metals; [0044] asphalt; [0045] bitumen; [0046] concrete, lightweight concrete, mortar, cement, fiber cement, brick, adobe, tile, slate, gypsum, gypsum panels, or natural stone, such as granite or marble; [0047] repair or levelling compounds based on PCC (polymer modified cement) or ECC (epoxy modified cement); [0048] timber, plywood, paper, cardboard, wood materials bonded with organic resins, resin-textile composites or so-called polymer composites; [0049] insulating foams, particularly out of EPS, XPS, PUR, PIR, rock wool, glass wool or foamed glass;

[0050] More preferably, the roof substrate is selected from the list consisting of metals, alloys, asphalt, bitumen, concrete, gypsum, timber and plywood.

Roofing Membrane:

[0051] In the present disclosure, the first roofing membrane and the second roofing membrane are sometimes collectively referred to as roofing membrane or roofing membranes. These terms are used interchangeably to describe any part or the whole of the roofing system being discussed. This approach simplifies the description and avoids repetitive language, making it easier to understand the scope and application of the invention.

[0052] The context in which these terms are used will specify whether they refer to the first roofing membrane, the second roofing membrane, or both.

[0053] Roofing membranes are essential for ensuring waterproofing and durability in modern roofing systems and come in various types, including single-ply, multi-ply, and liquid-applied membranes.

[0054] The term single-ply membrane designates in the present disclosure membranes comprising one single waterproofing layer whereas the term multi-ply membrane refers to membranes comprising more than one waterproofing layer having same or different compositions. Preferably, the roofing membrane are planar element.

[0055] 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.

[0056] Commonly used materials for roofing membranes include thermoplastics such as plasticized polyvinylchloride (p-PVC), thermoplastic polyolefins (TPE-O, TPO), and elastomers such as ethylene-propylene diene monomer (EPDM).

[0057] Polymeric roofing membranes are typically delivered to a construction site in rolls, transferred to the place of installation, unrolled, and adhered on the surface of the roof substrate.

[0058] The claimed roofing system of the present invention includes a first roofing membrane having a first upper surface and a first lower surface. The first upper surface refers to the top surface of the first roofing membrane, and the first lower surface refer to the bottom surface of the first roofing membrane. Similarly, the second upper surface refers to the top surface of the second roofing membrane, and the second lower surface refer to the bottom surface of the second roofing membrane.

[0059] In a step (ii) the first roofing membrane and the second roofing membrane are laid onto a surface of the roof substrate in such a manner that an edge of the first roofing membrane is adjacent to an edge of the second roofing membrane. The first roofing membrane is not in direct contact with the second roofing membrane and the first lower surface and the second lower surface are in direct contact with the roof substrate.

[0060] The first roofing membrane and the second roofing membrane are laid (or securely fastened) on the surface of the roofing substrate. The first lower surface and the second lower surface being in direct contact with the roof substrate. An edge of the first roofing membrane is positioned next to an edge of the second roofing membrane on the roof substrate, ensuring that the first roofing membrane does not directly touch the second roofing membrane, thus creating a gap or a joint between them.

[0061] Preferably, the first roofing membrane and the second roofing membrane are secured on the roofing substrate by adhesive and/or mechanically using screws, barbed plates or termination bars, preferably by termination bar.

[0062] Preferably, the edges of the roofing membranes are secured on the roofing substrate using termination bars.

[0063] The term termination bar refers to an elongate bar, typically made of metal, with a plurality of apertures. Mechanical fasteners are provided through the apertures of the termination bar and extend into the roof substrate, thereby further securing the roofing membranes to the roof substrate along the length of the termination bar.

[0064] In another embodiment, the roofing membranes are securely fastened to the roof substrate using suitable adhesives. The selection of suitable adhesive(s) depends on the compositions of both the roofing membrane and the roof substrate. Typically, roofing membranes are adhered by contact bonding or by using self-adhering roofing membranes. In case of contact bonding, both the membrane and the surface of the roof substrate are first coated with a solvent or water based contact adhesive after which the membrane is contacted with the surface of the substrate. The volatile components of the contact adhesive are flashed off to provide a partially dried adhesive film prior to contacting the membrane with the surface of the roof substrate.

[0065] In an another embodiment, roofing membranes utilized are self-adhering and provided with a pre-applied layer of adhesive, which is covered with a release liner to prevent premature unwanted adhesion and to protect the adhesive from moisture, fouling, and other environmental factors. At the time of use the release liner is removed and the roofing membrane is secured to the roof substrate without the use of additional adhesives. Roofing membranes having a pre-applied adhesive layer covered by release liner are also known as peel and stick membranes or self-adhering membranes.

[0066] Preferably, the roofing membranes are securely fastened to the roof substrate using a combination of adhesive and mechanical methods.

[0067] In the context of the present invention, the first roofing membrane and the second roofing membrane are not compatible with each other. A not compatible roofing membrane refers to a roofing membrane that cannot be effectively used in conjunction with certain other materials or membranes due to chemical, physical, or performance incompatibilities. This incompatibility can lead to a range of issues such as adhesion problems, unwanted chemical reactions, structural compatibility issues, thermal expansion and contraction, UV resistance etc.

[0068] The roofing membranes (i.e. first roofing membrane and the second roofing membrane) of the present invention may be a single layer or may be composed of multiple layers and may contain a reinforcing fabric or scrim reinforcement material in the center between two layers. Some roofing membranes may also have fleece attached to the bonding side when used with water-based adhesives or hot asphalt adhesives.

[0069] Preferably, the first roofing membrane comprises at least one polymer P1 selected from thermoplastic polyolefins (TPO) or a thermoplastic ethylene propylene diene terpolymer (EPDM), preferably thermoplastic polyolefins (TPO).

[0070] Thus, the first roofing membrane is composed of a composition comprising thermoplastic polyolefins (TPO) or a thermoplastic ethylene propylene diene terpolymer (EPDM), preferably the first roofing membrane is composed of a composition comprising thermoplastic polyolefin (TPO).

[0071] Term polyolefin refers in the present disclosure to homopolymers and copolymers obtained by polymerization of olefins. Suitable polyolefins for use as the at least one polymer includes, for example, thermoplastic polyolefins (TPO, TPO-E).

[0072] Especially suitable thermoplastic polyolefins include heterophasic propylene copolymers. These 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. Suitable commercially available heterophasic propylene copolymers include reactor blends of the base polyolefin and the polyolefin modifier, also known as in-situ TPOs or reactor TPOs or impact copolymers (ICP), which 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. Heterophasic propylene copolymers comprising polypropylene homopolymer as the base polymer are often referred to as heterophasic propylene copolymers (HECO) whereas heterophasic propylene copolymers comprising polypropylene random copolymer as the base polymer are often referred to as heterophasic propylene random copolymers (RAHECO). The term heterophasic propylene copolymer encompasses in the present disclosure both the HECO and RAHECO types of the heterophasic propylene copolymers.

[0073] Suitable commercially available heterophasic 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.

[0074] Further suitable polyolefins include propylene homopolymers, for example, isotactic polypropylene (iPP), syndiotactic polypropylene (sPP), and homopolymer polypropylene (hPP), and propylene copolymers, especially propylene--olefin copolymers. Ethylene copolymers, for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), and ethylene copolymers, particularly ethylene--olefin copolymers.

[0075] Suitable rubbers for use as the at least one polymer include, for example, styrene-butadiene rubber (SBR), ethylene propylene diene monomer (EPDM) rubber, butyl rubber, polyisoprene, polybutadiene, natural rubber, polychloroprene rubber, ethylene-propylene rubber (EPR), nitrile rubber, acrylic rubber, ethylene vinyl acetate rubber, and silicone rubber, and chemically crosslinked versions of these rubbers. Suitable examples of the TPO based roofing membranes includes Dow Tiempo 2000 TPO membrane available from Dow Roofing Systems of Holyoke Mass. Other examples include products from Carlisle SynTec of Carlisle, Pa., Firestone Building Products of Indianapolis, Ind., GAF Materials Corporation of Wayne, N.J., Johns Manville of Denver, Colo., and others.

[0076] Suitable examples of the EPDM based roofing membrane includes EPDM-Sure-Tough EPDM, EPDMFleeceBACK, EPDMSure-White roofing membrane available from Carlisle SynTec of Carlisle, Pa, Other examples include products from Polygomma, Techno Rubber Company Limited.

[0077] Preferably, the second roofing membrane comprises at least one polymer P2 selected from polyvinylchloride (PVC).

[0078] According to a preferred embodiment, polymer P2 is selected from polyvinylchloride (PVC). Thus, the second roofing membrane is composed of a composition comprising PVC.

[0079] Suitable PVC resins for use polymers P2 include ones having a K-value determined by using the method as described in ISO 1628-2-1998 standard in the range of 50-85, 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 C.

[0080] Suitable examples of the PVC based roofing membranes include Sarnafil PVC Roofing Membrane offered by Sika, Duro-Last Custom-Fabricated PVC Roof Membrane, Versico PVC Roofing Membrane, Elevate by Holcim, Carlisle Syntec, C3 Plus PVC from Cooley. Some other examples include products from IB Roof Systems, Flex Roofing Systems.

[0081] The first roofing membrane and the second roofing membrane can be a single- or multi-ply-membrane. The term single-ply membrane designates in the present disclosure membranes comprising one single waterproofing layer whereas the term multi-ply membrane refers to membranes comprising more than one waterproofing layer having same or different compositions.

[0082] According to one or more embodiments, the first roofing membrane comprises at least one waterproofing layer comprising at least 25 wt.-%, preferably at least 50 wt.-%, more preferably at least 60 wt.-%, of the at least one polymer P1.

[0083] According to one or more embodiments, the second roofing membrane comprises at least one waterproofing layer comprising at least 25 wt.-%, preferably at least 50 wt.-%, more preferably at least 60 wt.-%, of the at least one polymer P2.

[0084] Preferably, the first roofing membrane and the second roofing membranes have a thickness of 0.5-5 mm, preferably 0.75-3.5 mm, more preferably 1-3 mm, even more preferably 1-2.5 mm.

[0085] In the claimed method of the present invention, the first roofing membrane and the second roofing membrane are not in direct contact with each other. This prevents the migration of plasticizers from a PVC-based roofing membrane (i.e. the second roofing membrane) to a non-PVC-based roofing membrane (i.e. the first roofing membrane), thereby preventing any adverse effects on performance of the hybrid roofing system.

[0086] Preferably, the gap (or width of the joint) between the edge of the first roofing membrane and the edge of the second roofing membrane is less than 1 inch, preferably less than inch, more preferably less than inch.

Primer Layers:

[0087] In step (iii), a first polymer resin primer layer PR1 is applied to at least a portion of the first upper surface and a second polymer resin primer layer PR2 is applied to at least a portion of the second upper surface.

[0088] The first roofing membrane and the second roofing membrane are laid on the surface of the roof substrate. Thereafter, a first polymer resin primer layer PR1 and the second polymer resin primer layer PR2 are applied on the first upper surface and the second upper surface respectively.

[0089] In the context of the present invention the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2 are collectively referred as a primer layer at some instances.

[0090] Primers, also referred to as activators or adhesion promoters, are applied where the used adhesive does not achieve any, or only limited, adhesion to the substrate.

[0091] In the context of the present invention, in addition to the adhesion promoter the second polymer resin primer layer PR2 serve as a plasticizer barrier between the second roofing membrane (i.e. PVC based membrane) and subsequently applied roofing materials such as sealing strip and water impermeable liquid applied membrane M1.

[0092] In a preferred embodiment, the primer layer (i.e. the first polymer resin primer layer PR1 and/or the second polymer resin primer layer PR2) is applied using techniques such as brushing, rolling, or spraying to ensure a consistent and even coating. Brushing and rolling are preferred for smaller areas or detailed work, providing control and precision in application. Spraying, on the other hand, is efficient for covering large surfaces quickly and uniformly. Proper technique and equipment calibration are essential to maintain uniform coverage and optimal adhesion properties of the primer layer. Preferably, the primer layer is applied by using a roller made of polyethylene. More preferably, the primer layer is applied using a brush on roofing membranes.

[0093] The term primer refers in the present disclosure to a thin layer, typically thinner than 1 mm, particularly 1-200 m, preferably 1-100 m, of a solvent- or water-based composition, which is applied as a coating to a surface of a substrate.

[0094] In the context of the present invention the primer layer serves as an adhesion promoter to adhere the sealing strip to the roofing membranes. Firstly, primer is applied to the roofing membrane and thereafter the sealing strip is attached to it.

[0095] Preferably, the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2 covers more than 10%, preferably more than 20%, more preferably more than 30% of the first upper surface and the second upper surface respectively, to ensure optimal adhesion of subsequent roofing materials. Preferably, the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2 covers at least 6 inches, preferably at least 8 inches, more preferably at least 10 inches of the first upper surface and the second upper surface respectively, to ensure optimal adhesion of subsequent roofing materials.

[0096] In a preferred embodiment, the thickness of the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2 is 2-4 mils (50-100 microns) when wet.

[0097] Preferably, the first polymer resin primer layer PR1 is composed of a composition which is compatible with the first roofing membrane. The detailed composition of the first polymer resin primer layer PR1 is not particularly restricted but should be compatible with material used in the first roofing membrane (i.e. either TPO or EPDM).

[0098] According to one of the embodiment, the first polymer resin primer layer PR1 is a single-component, solvent-based primer designed to enhance adhesion between water impermeable liquid applied membrane M1 and flexible TPO/EPDM based roofing membranes. The primer is composed primarily of synthetic rubber in a hydrocarbon solvent, which ensures high viscosity for uniform coverage and effective adhesion.

[0099] Preferably, the first polymer resin primer layer PR1 is composed of a composition comprising synthetic rubber, preferably chloroprene synthetic rubber.

[0100] The first polymer resin primer layer PR1 is applied to at least a portion of the first upper surface of the first roofing membrane.

[0101] Suitable examples of the first polymer resin primer layer PR1 includes Sikalastic EPDM/TPO Primer Lo-VOC.

[0102] According to one of the embodiments, the second polymer resin primer layer PR2 is composed of a composition which is compatible with the second roofing membrane. The detailed composition of the second polymer resin primer layer PR2 is not particularly restricted but should be compatible with material used in the second roofing membrane (i.e. PVC). The second polymer resin primer layer PR2 also act as barrier for prevention of migration of plasticizers from the second roofing membrane.

[0103] Preferably, second polymer resin primer layer PR2 has a thickness thinner than 1 mm, particularly 1-500 m, preferably 1-300 m.

[0104] Preferably, the second polymer resin primer layer PR2 is composed of a composition comprising: [0105] at least one liquid epoxy resin LER; and [0106] at least one amine hardener AH.

[0107] Preferred one liquid epoxy resin LER are in particular aromatic epoxy resins, especially the glycidyl ethers of: [0108] bisphenol A, bisphenol F or bisphenol A/F, where A stands for acetone and F for formaldehyde, which served as reactants for the preparation of these bisphenols. In the case of bisphenol F, positional isomers may also be present, especially derived from 2,4- or 2,2-hydroxyphenylmethane. [0109] dihydroxybenzene derivatives such as resorcinol, hydroquinone or catechol; [0110] further bisphenols or polyphenols such as bis(4-hydroxy-3-methylphenyl) methane, 2,2-bis(4-hydroxy-3-methylphenyl) propane (bisphenol C), bis(3,5-dimethyl-4-hydroxyphenyl) methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis(4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis(4-hydroxyphenyl) butane (bisphenol B), 3,3-bis(4-hydroxyphenyl) pentane, 3,4-bis(4-hydroxyphenyl) hexane, 4,4-bis(4-hydroxyphenyl) heptane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,4-bis(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z), 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (bisphenol TMC), 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,4-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol P), 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol M), 4,4-dihydroxydiphenyl (DOD), 4,4-dihydroxybenzophenone, bis(2-hydroxynaphth-1-yl) methane, bis(4-hydroxynaphth-1-yl) methane, 1,5-dihydroxynaphthalene, tris(4-hydroxyphenyl) methane, 1,1,2,2-tetrakis(4-hydroxyphenyl) ethane, bis(4-hydroxyphenyl) ether or bis(4-hydroxyphenyl) sulfone; [0111] condensation products of phenols with formaldehyde that are obtained under acidic conditions, such as phenol novolaks or cresol novolaks, also called bisphenol F novolaks; [0112] aromatic amines such as aniline, toluidine, 4-aminophenol, 4,4-methylenediphenyldiamine, 4,4-methylenediphenyldi(N-methyl)amine, 4,4-[1,4-phenylenebis(1-methylethylidene)]bisaniline (bisaniline P) or 4,4-[1,3-phenylenebis(1-methylethylidene)]bisaniline (bisaniline M).

[0113] A preferred liquid epoxy resin LER is a liquid resin based on a bisphenol, in particular a bisphenol A diglycidyl ether and/or bisphenol F diglycidyl ether, as are commercially available, for example, from Dow, Huntsman or Momentive. These liquid resins have a viscosity that is low for epoxy resins and good properties as a coating when cured. They may contain proportions of solid bisphenol A resin or novolak glycidyl ethers.

[0114] Preferred amine hardener AH are selected from the list consisting of: [0115] aliphatic, cycloaliphatic or arylaliphatic primary di- or triamines, especially isophorone diamine (IPD) and m-xylylenediamine (MXDA), [0116] ether group-containing aliphatic primary di- or triamines, [0117] polyamines containing secondary amino groups, preferably 2-piperazin-1-ylethylamine, and [0118] adducts of these amines with epoxides or epoxy resins, in particular adducts with diepoxides or monoepoxides.

[0119] More preferred, the amine hardener AH consists of a mixture of said list.

[0120] Most preferred, the amine hardener AH consists of a mixture of: [0121] aliphatic, cycloaliphatic or arylaliphatic primary di- or triamines, especially isophorone diamine (IPD) and m-xylylenediamine (MXDA), and [0122] polyamines containing secondary amino groups, preferably 2-piperazin-1-ylethylamine.

[0123] Preferably, the epoxy resin composition has a water content of less than 5 wt.-%, preferably less than 3 wt. %, based on the total weight of the composition.

[0124] Preferably, the epoxy resin composition has, 2 minute after mixing all the components, a viscosity of less than 15000 cP, preferably less than 12500 cP, more preferably less than 10000 cP, using a Brookfield DV1 Viscometer with a HB-04 spindle @ 100 rpms at 23 C.

[0125] The polymer resin primer layer PR2 containing the epoxy resin composition is applied on top of the surface of the second roofing membrane by using any conventional techniques, for example, by means of a roller, brush, or by pouring-out and further distributed by means, for example, of a roller, a scraper, or a notched trowel.

Sealing Strip:

[0126] In a step (iv), a sealing strip having an upper major surface and a lower major surface limited between short and long edges is provided.

[0127] In the roofing industry, strips are often used to bond and/or connect two materials together, such as edge strips and roofing membranes. Sealing strips or sealing tapes are essential for maintaining the integrity of roofing systems and ensuring long-term protection against water infiltration. When selecting a sealing strip/tape, it is crucial to choose one that is compatible with the specific type of roofing membrane in use to ensure optimal performance and durability.

[0128] In this document the term Sealing strip preferably refers to a sheet-like articles having upper and lower major surfaces, i.e., top and bottom surfaces, limited by short and long edges, and a thickness of the strip defined there between.

[0129] In an embodiment of the invention, the sealing strip is field-fabricated by combining a urethane resin with a reinforcement layer, followed by an additional layer of urethane resin to create a sheet-like sealing strip.

[0130] In the present invention, the sealing strip is primarily used to bridge a joint formed between the edge of the first roofing membrane and the edge of the second roofing membrane.

[0131] According to one or more embodiments, sealing strip comprise(s) at least one polymer P3 selected from polyvinylchloride (PVC), polyolefin, halogenated polyolefin, rubber, and ketone ethyl ester (KEE).

[0132] Suitable PVC resins for use as polymer P3 include ones having a K-value determined by using the method as described in ISO 1628-2-1998 standard in the range of 50-85, 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 C.

[0133] According to one or more embodiments, the sealing strip comprise(s) at least 25 wt.-%, preferably at least 50 wt.-%, more preferably at least 60 wt.-%, based on the total weight of the sealing strip of the at least one polymer P3.

[0134] The thickness of the sealing strip is in the range of 0.1-5 mm, preferably 0.3-3.5 mm, more preferably 0.5-3 mm. The thickness can be determined by using the measurement method as defined in DIN EN 1849-2 standard.

[0135] According to one or more embodiments, the sealing strip has a width of 10-100 cm, preferably 15-75 cm and/or the first long edge portion of the lower major surface of the sealing strip has a width of 2.5-35 cm, preferably 5-30 cm.

[0136] Preferably, the sealing strip is a 6-9 inches (where an inch is 2.54 cm) wide membrane strip coated with a pressure-sensitive adhesive layer.

[0137] In an embodiment, the sealing strip is self-adhesive fabric tape. The lower major surface of the sealing strip is coated with a with a pressure-sensitive (PS) adhesive layer. Finally, the PS layer is covered with the silicone-coated release sheet. The sealing strip will be 6-12 inches (15.24-30.48 cm) wide, typically 6-9 inches (15.24-22.86 cm) wide.

[0138] Preferably, the sealing strip is a self-adhesive sealing strip, preferably an adhesive tape, more preferably a self-adhesive tape, most preferably a self-adhesive fabric tape.

[0139] In a preferred embodiment of the present invention, the sealing strip is self-adhering polymeric rubberized tape with plastic release liner on underside and woven polyester facer on top side.

[0140] In a preferred embodiment of the present invention, the sealing strip is in the form of a fibre reinforcement mesh. The fibre reinforcement mesh is preferably a non-woven polyester fibre mesh, or more preferably a non-woven glass fibre mesh.

[0141] Suitable examples of the sealing strip include, but not limited to, SikaPlan WP Tape-20 (SIKA), Sika Joint Tape SA 6 (SIKA), Sarnatape (SIKA), 3M Venture Tape (3M), PLIOSEAL (Ashland) or 510 (Adco) or 505 (Adco), EverGuard TPO Seam Tape (GAF), RUBEROID SA (GAF), JM TPO Peel & Stick Seam Tape (Johns Manville), FullForce EPDM Tape (Firestone Building Products), Sure-Weld TPO Pressure-Sensitive Coverstrip (Carlisle SynTec Systems). Most preferably, the sealing strip is Sika Joint Tape SA 6 provided by Sika technology AG.

[0142] In a step (v), the sealing strip is adhesively bonded via the lower major surface to at least a portion of the first polymer resin primer layer PR1 and at least a portion of the second polymer resin primer layer PR2 so that a connection gets established between the first roofing membrane and the second roofing membrane.

[0143] The sealing strip is directly applied to the edge portions of the first roofing membrane and the second roofing membrane. The sealing strip will bind to the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2. The second polymer resin primer layer PR2 will act as a barrier layer and will stop migration of plasticizers between the sealing strip and the second roofing membrane (i.e. PVC based roofing membrane).

[0144] The sealing strip is applied to the joint created between the edge portions of the first roofing membrane and the second roofing membrane. Preferably, the sealing strip is centered over the joint, extending at least 1 inch, preferably at least inch beyond each side of the joint.

Water Impermeable Liquid Applied Membrane M1

[0145] In step vi), a water impermeable liquid applied membrane M1 is applied to the upper major surface of the sealing strip, the first polymer resin primer layer PR1 and the second polymer resin primer layer PR2.

[0146] In this document the term water impermeable liquid applied membrane preferably refers to a material which is applied in liquid form as a layer onto a substrate, and which cures to form an elastic membrane making the substrate waterproof.

[0147] Preferably, the water impermeable liquid applied membrane M1 is applied to cover at least a portion of the first polymer resin primer layer PR1, at least a portion of the second polymer resin primer layer PR2 and the sealing strip.

[0148] Preferably, the water impermeable liquid applied membrane M1 is applied by the application of a reactive composition RC1 in liquid form and letting the applied composition cure.

[0149] Said reactive composition is preferably a material which is applied in liquid form as a layer onto a substrate, and which cures to form an elastic membrane making the substrate waterproof.

[0150] Preferably, the reactive composition RC1 has a water content of less than 10 wt.-%, preferably less than 5 wt. %, more preferably less than 3 wt. %, based on the total weight of the composition.

[0151] Preferably, reactive compositions RC1 is selected from the list consisting of reactive one-part polyurethane compositions, reactive two-part polyurethane compositions and reactive two-part polyurea compositions, preferably reactive one-part polyurethane compositions.

[0152] Preferably, the reactive one-part polyurethane composition contains: [0153] at least one isocyanate-functional polyurethane polymer; and [0154] at least one latent hardener.

[0155] The isocyanate-functional polymer is preferably liquid at room temperature.

[0156] Preferred are isocyanate-functional polymers of low viscosity, preferably with a viscosity of less than 50 Pa.Math.s, more preferably less than 30 Pa.Math.s, particularly less than 20 Pa.Math.s, measured by a cone-plate-viscometer with a cone diameter of 25 mm, cone angle of 1 at a cone-plate-distance of 0.05 mm and a shear rate of 10 s-1 at 20 C.

[0157] The isocyanate-functional polymer preferably has an NCO-content in the range of 1 to 8 weight-%, preferably 1.5 to 6 weight-%.

[0158] The isocyanate-functional polymer preferably has an average molecular weight M.sub.n in the range of 1000 to 15000 g/mol, preferably 1500 to 12000 g/mol.

[0159] The isocyanate-functional polymer is preferably obtained from the reaction of an aliphatic isocyanate, preferably isophorone diisocyanate, and at least one polyol.

[0160] Preferably, the reaction is done in a molar NCO/OH ratio of at least 3/1, preferably in the range of 3/1 to 10/1, more preferably 3/1 to 8/1.

[0161] The reaction between isocyanate and the polyol is preferably conducted in the absence of moisture at a temperature in the range of 20 to 160 C., preferably 40 to 140 C., possibly in the presence of a suitable catalyst.

[0162] The polyol is preferably selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols and polyacrylate polyols.

[0163] Preferred are polyether polyols, preferably with repetitive units selected from 1,2-ethyleneoxy, 1,2-propyleneoxy, 1,3-propyleneoxy, 1,2-butyleneoxy and 1,4-butyleneoxy. Particularly preferred are 1,2-propyleneoxy units, optionally in combination with some 1,2-ethyleneoxy units at the end of the chains. Further particularly preferred are 1,4-butyleneoxy units.

[0164] Preferred are polyether polyols with a content of unsaturation below 0.02 mEq/g, preferably below 0.01 mEq/g.

[0165] Preferred are polyoxypropylene diols or triols, which optionally are ethyleneoxide-endcapped, with an OH-number in the range of 10 to 250 mg KOH/g, preferably 20 to 125 mg KOH/g.

[0166] The polyol preferably has an average OH-functionality in the range of 1.7 to 3.

[0167] Particularly preferred are polyoxypropylene diols, which optionally are ethyleneoxide-endcapped, with an average molecular weight Mn in the range of 450 to 12000 g/mol, preferably 1000 to 6000 g/mol.

[0168] Particularly preferred are further trimethylolpropane or glycerine started poly-oxypropylene triols, which optionally are ethyleneoxide-endcapped, with an average molecular weight Mn in the range of 3000 to 8000 g/mol.

[0169] Particularly preferred are further poly(oxy-1,4-butylene) diols, particularly with an OH-number in the range of 50 to 180 mg KOH/g, particularly with an average molecular weight Mn in the range of 650 to 2000 g/mol.

[0170] Preferred latent hardeners are blocked amines which have a blocked, hydrolytically activatable amino group and either at least one further blocked, hydrolytically activatable amino group or at least one reactive group R which is selected from the group consisting of hydroxyl group, mercapto group and secondary amino group.

[0171] The blocked, hydrolytically activatable amino group of the blocked amine is selected, in particular, from the group consisting of enamino groups, oxazolidino groups, ketimino groups and aldimino groups. Such blocked amines are substances known in polyurethane chemistry which are used as so-called latent hardeners in compositions containing isocyanate groups.

[0172] In the present document, oxazolidino group refers to both tetrahydrooxazole groups (5-ring) and tetrahydrooxazine groups (6-ring).

[0173] Preferably, the blocked, hydrolytically activatable amino group of the blocked amine is an aldimino group.

[0174] The blocked amine can be obtained, in particular, from the condensation reaction of a primary or secondary amine with a ketone or aldehyde. Particularly suitable as ketones are acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl pentyl ketone, methyl isopentyl ketone, diethyl ketone, dipropyl ketone, diisopropyl ketone, dibutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and actetophen. Particularly suitable as aldehyde are formaldehyde, acetaldehyde, propanal, 2-methylpropanal, butanal, 2-methylbutanal, 2-ethylbutanal, pentanal, 2-methylpentanal, 3-methylpentanal, 4-methylpentanal, 2,3-dimethylpentanal, hexanal, 2-ethyl-hexanal, heptanal, octanal, nonanal, decanal, undecanal, 2-methyl-undecanal, dodecanal, methoxyacetaldehyde, cyclopropanecarboxaldehyde, cyclopentanecarboxaldehyde, cyclohexanecarboxaldehyde, diphenylacetaldehyde, benzaldehyde and substituted benzaldehydes.

[0175] A blocked amine having at least one oxazolidino group can be obtained in particular from the condensation reaction of at least one hydroxyamine in which the hydroxyl and primary amino groups are separated by an optionally substituted ethylene or trimethylene radical, with at least one ketone or aldehyde, in particular formaldehyde or one of the enolizable ketones or aldehydes mentioned; The aldehydes, in particular 2-methylpropanal, are particularly suitable. Particularly suitable as hydroxyamine are diethanolamine and diisopropanolamine, which lead to hydroxyoxazolidines from which polyoxazolidines can easily be prepared, for example by reaction with a polyisocyanate or a polyester.

[0176] A blocked amine having at least one ketimino or aldimino group can be obtained in particular from the condensation reaction of an amine having at least one primary amino group with at least one ketone or aldehyde, as mentioned above. If a ketone is used to block a primary amino group, a ketimino group is formed, while an aldimino group is formed when an aldehyde is used.

[0177] Most preferred, the latent hardener is a blocked amine having at least one aldimino group.

[0178] Preferably, said blocked amine is present in an amount that the ratio between the total number of aldimine groups to the total number of isocyanate groups is in the range of 0.3 to 1, preferably 0.4 to 1, more preferably 0.5 to 1.

[0179] Preferably, the reactive one-part polyurethane composition further contains fillers. Suitable fillers are ground or precipitated calcium carbonates (chalk), which are optionally surface coated with a fatty acid such as stearate, barium sulfate (barytes), slate, silicates (quartz), magnesiosilicates (talc) or alumosilicates (clay, kaolin), dolomite, mica, glass bubbles, silicic acid, particularly highly dispersed silicic acids from pyrolytic processes (fumed silica), carbon black, microspheres, pigments, particularly titanium dioxide or iron oxides, or flame-retarding fillers such as aluminium hydroxides, particularly aluminium trihydroxide (ATH), magnesium dihydroxide, antimony trioxide, antimony pentoxide, boric acid, zinc borate, zinc phosphate, melamine borate, melamine cyanurate, ethylenediamine phosphate, ammonium polyphosphate, di-melamine orthophosphate, di-melamine pyrophosphate, hexabromocyclododecane, decabromodiphenyl oxide and tris(bromoneo-pentyl) phosphate.

[0180] Preferred fillers are chalk, barytes, fumed silica and/or ATH.

[0181] Preferably, the reactive one-part polyurethane composition further contains plasticizers. Suitable plasticizers are phthalates, particularly diisononyl phthalate (DINP) or diisodecyl phthalate (DIDP), hydrogenated phthalates, particularly hydrogenated DINP, which is diisononyl-1,2-cyclohexane dicarboxylate (DINCH), terephthalates, particularly bis(2-ethylhexyl) terephthalate or diisononyl terephthalate, hydrogenated terephthalates, particularly bis(2-ethylhexyl)-1,4-cyclohexane dicarboxylate, trimellitates, adipates, particularly dioctyl adipate (DOA), azelates, sebacates, citrates, benzoates, glycol ethers, glycol esters, organic sulfonates or phosphates, particularly diphenylcresyl phosphate (DPK), polybutenes, polyisobutenes or plasticizers obtained from natural fats or oils such as epoxidized soy or linseed oil.

[0182] Preferably, the reactive one-part polyurethane composition further contains catalysts. Suitable catalysts for the acceleration of the latent hardeners, preferably aldimine hydrolysis, are acid catalysts, particularly carboxylic acids or sulfonic acids, preferably aromatic carboxylic acids such as benzoic acid or salicylic acid.

[0183] Suitable catalysts are catalysts for the acceleration of the reaction of isocyanate groups, particularly metal catalysts, preferably dialkyltin complexes, in particular dibutyltin or dioctyltin carboxylates or acetoacetonates such as dibutyltindilaurate (DBTDL), dibutyltindi(acetoacetate) (DBT(acac).sub.2) or dioctyltindilaurate (DOTDL), or amine catalysts, preferably tertiary amino ethers, in particular 2,2-dimorpho-linodiethylether (DMDEE).

[0184] Preferably, the reactive one-part polyurethane composition further contains additives selected from the group consisting of UV stabilizers, wetting agents, flow enhancers, leveling agents, defoamers, deaerating agents and biocides.

[0185] Preferably, the reactive compositions RC1 is reactive one-part polyurethane composition containing: [0186] an amount of isocyanate-functional polymers in the range of 15 to 80 weight-%, particularly 20 to 50 weight-%, in relation to the total composition; and [0187] an amount of latent hardener, preferably aldimines, in the range of 0.5 to 25 weight-%, preferably 1 to 20 weight-%, in relation to the total composition; and [0188] an amount of plasticizers in the range of 0 to 40 weight-%, preferably 10 to 30 weight-%, in relation to the total composition; and [0189] an amount of fillers in the range of 0 to 80 weight-%, preferably 20 to 60 weight-%, in relation to the total composition, preferably, the filler contains at least one flame-retarding ingredient, more preferably aluminium trihydroxide (ATH).

[0190] The reactive one-part polyurethane composition is preferably formulated as a single-pack composition, prepared by mixing all ingredients under exclusion of moisture to obtain a macroscopically homogeneous fluid or paste and stored in a moisture-tight container at ambient temperatures. A suitable moisture-tight container consists preferably of an optionally coated metal or plastic. It is preferably a bucket, a barrel, a hobbock, a bag, a sausage, a cartridge, a can, a bottle or a tube.

[0191] The process of curing begins when the reactive one-part polyurethane composition is applied and gets in contact with moisture, especially atmospheric moisture. Upon curing, the isocyanate groups react under the influence of moisture with the hydrolyzing latent groups of the latent hardener, preferably hydrolyzing aldimine groups. Further, isocyanate groups react with each other under the influence of moisture. As a result of these reactions, the composition cures to form an elastic material.

[0192] The reactive one-part polyurethane composition is preferably applied at ambient conditions, preferably in a temperature range of 10 to 50 C., more preferably 5 to 45 C., particularly 0 to 40 C. The curing of the composition preferably also takes place at ambient conditions.

[0193] The reactive one-part polyurethane composition preferably has a sufficient open time to allow precise positioning and large surface applications and a fast-curing progress, whereby the composition soon becomes tack-free and shows a fast build-up of mechanical strength and elasticity.

[0194] Open time is the time period, within which the applied composition can be processed or reworked without any negative effect. It is over when the viscosity of the composition due to progressing curing has risen too much, at the latest when a skin is formed on the surface. The time period, until a skin is formed on the surface, is called skin formation time or skinning time.

[0195] Preferably, the water impermeable liquid applied membrane M1 comprise a fibre reinforcement mesh, preferably a non-woven polyester fibre mesh or a non-woven glass fibre mesh, preferably the fibre reinforcement mesh was worked into the reactive composition RC1, as long as the composition was still liquid.

[0196] The thickness of the water impermeable liquid applied membrane M1 is preferably in the range of 0.5-5 mm, preferably 1.0-3.5 mm, more preferably 1.5-3 mm.

[0197] Another aspect of the present invention is a roof system comprising, [0198] a roof substrate (1); [0199] a first roofing membrane (2) having a first upper surface and a first lower surface, wherein a first polymer resin primer layer PR1 (4) is applied to at least a portion of the first upper surface; [0200] a second roofing membrane (3) having a second upper surface and a second lower surface, wherein a second polymer resin primer layer PR2 (5) is applied to at least a portion of the second upper surface, wherein the first roofing membrane (2) and the second roofing membrane (3) are laid on a surface of the roof substrate (1) so that an edge of the first roofing membrane (2) is adjacent to an edge of the second roofing membrane (3), wherein the first lower surface and the second lower surface are in direct contact with the roof substrate (1), and wherein the first roofing membrane (2) is not in direct contact with the second roofing membrane (3); [0201] a sealing strip (6) having an upper major surface and a lower major surface limited between short and long edges, wherein the sealing strip (6) is adhesively bonded via the lower major surface to at least a portion of the first polymer resin primer layer PR1 (4) and at least a portion of the second polymer resin primer layer PR2 (5) so that a connection gets established between the first roofing membrane (2) and the second roofing membrane (3); and [0202] a water impermeable liquid applied membrane M1 (7), wherein the water impermeable liquid applied membrane M1 (7) is applied to the upper major surface of the sealing strip (6), optionally to the first polymer resin primer layer PR1 (4) and the second polymer resin primer layer PR2 (5), wherein the water impermeable liquid applied membrane M1 (7) is allowed to cure in order to form a watertight seal between the first roofing membrane (2) and the second roofing membrane (3).

[0203] Preferably, the roofing membranes (i.e. collectively first and second roofing membranes) covers more than 80%, preferably more than 90%, more preferably all of the upper major surface of the roof substrate (1).

[0204] Preferred embodiments of the roof substrate (1), the first roofing membrane (2), the second roofing membrane (3), the first polymer resin primer layer PR1 (4), the second polymer resin primer layer PR2 (5), the sealing strip (6), the water impermeable liquid applied membrane M1 (7) have already been discussed above.

EXPERIMENTS

[0205] Example 1: Water impermeable liquid applied membrane M1 is used to seal a joint between adjacent roofing membranes of a hybrid roofing system consisting TPO and PVC membrane.

[0206] A TPO membrane and a PVC Membrane are placed adjacent to one another (edge to edge) on a roof substrate in such a manner that they are not in direct contact with each other. The edges of the membrane are affixed to the substrate using fasteners and a termination bar. Since the membranes are not in direct contact or touching each other a gap or a joint is created between the edges of the roofing membranes. The edge of the TPO membrane is coated with a EPDM/TPO primer (for LAM). The edge of the PVC membrane is coated with EP Primer. A sealing strip having a width of 400 mm was cut from a roll of SikaPlan WP Tape-20 and bonded to primed surfaces of the TPO and PVC based roofing membranes. The sealing strip (i.e. a self-adhered fabric tape) is applied to both membranes in such a manner that the sealing strip spans the distance across the joint. Liquid applied roofing membrane (Roof pro LAM) is applied to the sealing strip and the upper surface of the PVC and TPO membranes that have been coated with the primer. This seal the joint or a watertight durable joint is formed.

[0207] Example 2: Water impermeable liquid applied membrane M1 is used to seal a joint between adjacent roofing membrane of a hybrid roofing system consisting EPDM and PVC membrane.

[0208] A EPDM membrane and a PVC Membrane are placed adjacent to one another (edge to edge) on a roof substrate in such a manner that they are not in direct contact with each other. The edges of the membrane are affixed to the substrate using fasteners and a termination bar. Since the membranes are not in direct contact or touching each other a gap or a joint is created between the edges of the roofing membranes. The edge of the EPDM membrane is coated with a TPO/EPDM primer (for LAM). The edge of the PVC membrane is coated with EP Primer. A sealing strip having a width of 400 mm was cut from a roll of SikaPlan WP Tape-20 and bonded to primed surfaces of the EPDM and PVC based roofing membranes. The sealing strip (i.e. a self-adhered fabric tape) is applied to both membranes in such a manner that the sealing strip spans the distance across the joint. Liquid applied roofing membrane (Roof pro LAM) is applied to the sealing strip and the upper surface of the PVC and EPDM membranes that have been coated with the primer. This seal the joint or a watertight durable joint is formed.