ROOFING SYSTEM AND INSULATION ELEMENT FOR A FLAT ROOF OR A FLAT INCLINED ROOF

Abstract

The disclosure relates to a roofing system for a flat roof or a flat inclined roof of a building with a thermal and/or acoustic insulation, consisting of a structural support, a deck, optionally a vapour control layer, a waterproof membrane and at least one insulation element being a bonded mineral fibre product made of mineral fibres, preferably stone wool fibres, and a cured aqueous binder, whereby the cured aqueous binder prior to curing comprises a component (i) in form of one or more oxidized lignins, a component (ii) in form of one or more cross-linkers, a component (iii) in form of one or more plasticizers, and whereby the insulation element has a bulk density between 70 kg/m.sup.3 and 250 kg/m .sup.3.

Claims

1. A roofing system for a flat roof or a flat inclined roof of a building with a thermal and/or acoustic insulation, consisting of a structural support, a deck, optionally a vapour control layer, a waterproof membrane and at least one insulation element being a bonded mineral fibre product made of mineral fibres, preferably stone wool fibres, and a cured aqueous binder composition, whereby the aqueous binder composition prior to curing comprises a component (i) in form of one or more oxidized lignins, a component (ii) in form of one or more cross-linkers, a component (iii) in form of one or more plasticizers, and whereby the insulation element has a bulk density between 70 kg/m.sup.3 and 250 kg/m.sup.3.

2. The roofing system according to claim 1, whereby the insulation element has a loss on ignition (LOI) within the range of 2 to 8 wt.-%, preferably 2 to 5 wt.-%.

3. The roofing system according to claim 1, having insulation elements with a compression strength between 50 and 130 kPa measured in accordance with European Standard EN 826: 2013.

4. The roofing system according to claim 1, having insulation elements with a delamination strength between 20 and 50 kPa measured in accordance with European Standard EN 1607:2013.

5. The roofing system according to claim 1, wherein component (i) is in form of one or more ammonia-oxidized lignins (AOL's).

6. The roofing system according to claim 1, wherein the component (ii) comprises one or more cross-linkers selected from β-hydroxyalkylamide-cross-linkers and/or oxazoline-cross-linkers.

7. The roofing system according to claim 1, wherein the component (ii) comprises one or more cross-linkers selected from the group consisting of polyethylene imine, polyvinyl amine, fatty amines; and/or one more cross-linkers in form of fatty amides; and/or one or more cross-linkers selected from the group consisting of dimethoxyethanal, glycolaldehyde, glyoxalic acid; and/or one or more cross-linkers selected from polyester polyols, such as polycaprolactone; and/or one or more cross-linkers selected from the group consisting of starch, modified starch, CMC; and/or one or more cross-linkers in form of aliphatic multifunctional carbodiimides; and/or one or more cross-linkers selected from melamine based cross-linkers, such as a hexakis(methylmethoxy)melamine (HMMM) based cross-linkers.

8. The roofing system according to claim 1, comprising component (ii) in an amount of 1 to 40 wt.-%, such as 4 to 20 wt.-%, such as 6 to 12 wt.-%, based on the dry weight of component (i).

9. The roofing system according to claim 1, wherein component (iii) comprises one or more plasticizers selected from the group consisting of polyethylene glycols, polyethylene glycol ethers, polyethers, hydrogenated sugars, phthalates and/or acids, such as adipic acid, vanillic acid, lactic acid and/or ferullic acid, acrylic polymers, polyvinyl alcohol, polyurethane dispersions, ethylene carbonate, propylene carbonate, lactones, lactams, lactides, acrylic based polymers with free carboxy groups and/or polyurethane dispersions with free carboxy groups.

10. The roofing system according to claim 1, wherein component (iii) comprises one or more plasticizers selected from the group consisting of fatty alcohols, monohydroxy alcohols, such as pentanol, stearyl alcohol; and/or one or more plasticizers selected from the group consisting of alkoxylates such as ethoxylates, such as butanol ethoxylates, such as butoxytriglycol; and/or one or more plasticizers in form of propylene glycols; and/or one or more plasticizers in form of glycol esters; and/or one or more plasticizers selected from the group consisting of adipates, acetates, benzoates, cyclobenzoates, citrates, stearates, sorbates, sebacates, azelates, butyrates, valerates; and/or one or more plasticizers selected from the group consisting of phenol derivatives, such as alkyl or aryl substituted phenols; and/or one or more plasticizers selected from the group consisting of silanols, siloxanes; and/or one or more plasticizers selected from the group consisting of sulfates such as alkyl sulfates, sulfonates such as alkyl aryl sulfonates such as alkyl and/or sulfonates, phosphates such as tripolyphosphates; and/or one or more plasticizers in form of hydroxy acids; and/or one or more plasticizers selected from the group consisting of monomeric am ides, such as acetam ides, benzamide, fatty acid amides such as tall oil am ides; and/or one or more plasticizers selected from the group consisting of quaternary ammonium compounds such as trimethylglycine, distearyldimethylammoniumchloride; and/or one or more plasticizers selected from the group consisting of vegetable oils such as castor oil, palm oil, linseed oil, tall oil, soybean oil; and/or one or more plasticizers selected from the group consisting of hydrogenated oils, acetylated oils; and/or one or more plasticizers selected from acid methyl esters; and/or one or more plasticizers selected from the group consisting of alkyl polyglucosides, gluconam ides, am inoglucoseam ides, sucrose esters, sorbitan esters; and/or one or more plasticizers selected from the group consisting of polyethylene glycols, polyethylene glycol ethers.

11. The roofing system according to claim 1, wherein the component (iii) is present in an amount of 0.5 to 50, preferably 2.5 to 25, more preferably 3 to 15 wt.-%, based on the dry weight of component (i).

12. The roofing system according to claim 1, comprising a further component (iv) in form of one or more coupling agents, such as organofunctional silanes in the binder.

13. The roofing system according to claim 1, further comprising a component (v) in form of one or more components selected from the group of ammonia, amines or any salts thereof in the binder.

14. The roofing system according to claim 1, comprising a further component in form of urea in the binder, in particular in an amount 5 to 40 wt.-%, such as 10 to 30 wt.-%, such as 15 to 25 wt.-%, based on the dry weight of component (i).

15. The roofing system according to claim 1, whereby the binder consists essentially of a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers; a component (iii) in form of one or more plasticizers; a component (iv) in form of one or more coupling agents, such as organofunctional silanes; optionally a component in form of one or more compounds selected from the group of ammonia, amines or any salts thereof; optionally a component in form of urea; optionally a component in form of a more reactive or non-reactive silicones; optionally a hydrocarbon oil; optionally one or more surface active agents; water.

16. An insulation element for a roofing system according to claim 1, made of mineral fibres, preferably stone wool fibres, and a cured aqueous binder composition, whereby the aqueous binder composition prior to curing comprises a component (i) in form of one or more oxidized lignins, a component (ii) in form of one or more cross-linkers, a component (iii) in form of one or more plasticizers and whereby the insulation element has a bulk density between 70 kg/m.sup.3 and 250 kg/m.sup.3.

17. (canceled)

18. An insulation element for a roofing system for a flat roof or a flat inclined roof of a building according to claim 1, comprising a first layer comprising stone wool fibres and a binder and a second layer made of a glass fleece, whereby the second layer is fixed to a major surface of the first layer by an adhesive, whereby the first layer is made of at least one lamella having a fibre orientation predominantly perpendicular to major surfaces of the second layer, and whereby the first layer contains a cured binder, wherein the adhesive is arranged partly in an area between fibres close to the major surface of the first layer directed to the second layer and in an area close to the major surface of the second layer directed to the first layer so that the adhesive connects the first layer and the second layer in such a way that forces directed perpendicular to the second layer can be compensated by the tensile strength of the second layer in combination with the adhesive and/or the deflection of the fibres of the first layer causing a maximum deformation of ≤5% of the thickness of the insulation element.

Description

DRAWINGS

[0415] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0416] The present disclosure is further described in the following referring to the accompanying drawings in which the figures show the following:

[0417] FIG. 1 shows a part of a first embodiment of a roofing system for a flat roof in cross-section;

[0418] FIG. 2 shows a part of a second embodiment of a roofing system for a flat roof in cross-section;

[0419] FIG. 3 shows a diagram showing the delamination strength of an insulation element used in a roofing system compared to the delamination strength of an insulation element according to the prior art;

[0420] FIG. 4 shows a diagram showing the delamination strength of an insulation element used in a roofing system after ageing compared to the delamination strength of an insulation element according to the prior art after ageing;

[0421] FIG. 5 shows a diagram showing the compression strength of an insulation element used in a roofing system compared to the compression strength of an insulation element according to the prior art;

[0422] FIG. 6 shows a diagram showing the compression strength of an insulation element used in a roofing system after ageing compared to the compression strength of an insulation element according to the prior art after ageing;

[0423] FIG. 7 shows a section from a possible lignin structure;

[0424] FIG. 8 shows different lignin precursors and common interunit linkages;

[0425] FIG. 9 shows four groups of technical lignins available in the market and

[0426] FIG. 10 shows a summary of the properties of the technical lignins.

[0427] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0428] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0429] FIG. 1 shows a first embodiment of a part of a flat roof 1 comprising a structural support 2, a vapour control layer 3, an insulation element 4 and an overlying waterproof membrane 20. The insulation element 4 is a bonded mineral fibre product made of mineral fibres and a binder.

[0430] The overlying waterproof membrane 20 is connected to the insulation element 4 via an adhesive 9 which can be an integral part of the membrane 20. The adhesive 9 can be a bituminous adhesive which is activated by a burner as usually used in roofing works, i.e. membrane 20 is torched onto the insulation element 4. A dotted line in the insulation element 4 indicates an area 10 into which molten bituminous adhesive 9 diffuses before hardening and connecting the membrane 20 to the insulation element 4.

[0431] FIG. 2 shows a second embodiment of a part of a flat roof 1 according to the disclosure comprising a structural support 2, a vapour control layer 3, an insulation element 4 and a waterproofing membrane (not shown but comparable to FIG. 1). The insulation element 4 comprises a first layer 5 comprising stone wool fibres and a binder and a second layer 6 made of a fabric of a glass fleece, having an E-modulus of 573 MPa. The tensile strength of the glass fleece is 71 N.

[0432] The first layer 5 is represented by one or more lamella having a fibre orientation predominantly perpendicular to a major surface 7 of the second layer 6. The lamella and therefore the first layer 5 have a density of 110 kg/m.sup.3 and a typical thickness of 150 mm. The mineral fibres are bonded together via the binder being cured in a hardening oven before the second layer 6 is fixed to a surface 8 of the first layer 5 via an adhesive 9. The adhesive 9 in this special embodiment might be chosen from melamine urea formaldehyde, preferably as two-component glue, waterborne acrylic glue, phenol formaldehyde powder binder, waterborne neoprene foam glue, polyamide based powder glue, polyurethane glue, preferably as two-component glue, polyurethane moisture curing glue or sealing modified binder, preferably as one-component moisture curing glue. However, preferably the adhesive 9 in this special embodiment equals the binder composition utilized to bind the mineral fibres of the insulation element 4.

[0433] All these adhesives 9 build up a good connection to mineral fibres and all these adhesives 9 are able to build up nearly closed layers in the area of the lamella as well as in the area of the fabric thereby strengthening the insulation element 4 in a direction parallel to the major surfaces 7 of the lamellae.

[0434] The adhesive 9 is arranged partly in an area 10 close to the major surface 8 of the first layer 5 directed to the second layer 6 and in an area 11 close to the major surface 7 of the second layer 6 directed to the first layer 5 so that the adhesive 9 connects the first layer 5 and the second layer 6 in such a way that forces directed perpendicular to the second layer 6 can be compensated by the tensile strength of the second layer 6 in combination with the adhesive 9 and/or the deflection of the fibres of the first layer 5. Such a force of e.g. 80 kPa directed perpendicular to the second layer 6 causes a limited deformation of smaller 5% of the insulation element 4 (first and second layer 5, 6) and therefore of not more than 7,5 mm related to the thickness of 150 mm of the first layer 5. The thickness of the second layer 6 is approximately not more than 1 mm and can therefore be disregarded in this calculation. A sufficient amount of adhesive 9 is arranged between the fibres of the first layer 5 thereby surrounding the fibres and building up a layer of adhesive 9 being anchored in the first layer 5.

[0435] The adhesive 9 is arranged with an amount of 80 g/m.sup.2 of liquid adhesive between the two layers 5 and 6 as an acrylic glue. A sufficient amount of the adhesive 9 diffuses in the first layer 5 and the second layer 6. The adhesive 9 constitutes therefore a layer connecting the first layer 5 and the second layer 6 and is anchored in both layers 5, 6.

[0436] The binder used in the insulation element 4 comprises a first component in form of one or more ammonia-oxidized lignins.The diagram according to FIG. 3 shows absolute values of the delamination strength of an insulation element 4 according to the disclosure (graph C.sub.2) compared with the delamination strength of an insulation element containing one of the assignees prior art non-added formaldehyde binder shown in graph A.sub.2 and the delamination strength of an insulation element containing traditional phenol-urea-formaldehyde binder shown in graph B.sub.2.

[0437] The delamination strength is measured according to EN 1607:2013 and the first initial measurement is carried out on unaged samples immediately or shortly after production of the insulation element 4 . This initial testing and the respective average result of a representative number of samples is illustrated at time ‘0’ on the x-axis of the diagram. Said time ‘0’ corresponds with day ‘0’ respectively the start of the accelerated ageing test according to the following description below.

[0438] In order to determine the ageing resistance of mineral fibre products exposed to moisture and heating during the service life of constructions, such mineral fibre products with focus on mechanical properties are subjected to accelerated ageing. The ageing resistance is defined as the ability of the product to maintain the original mechanical properties, and it is calculated as the aged strength in per cent of the original strength. The test procedure follows the so called Nordtest method NT Build 434: 1995.05, extended to 28 days.

[0439] The aim of said method is to expose insulation materials to accelerated ageing due to increased temperature and heat. It is applicable to all insulation materials manufactured as insulation boards. The method is not predictive i.e. it is not intended for assessment of the service life, but it is a precondition for a satisfactory performance that ageing due to this method does not cause major changes in the properties of the materials under investigation. Experiences over more than two decades with the Nordtest method have proven to deliver reliable data to ensure satisfactory mechanical performance of inter alia mineral fibre products as insulation elements for use in roofing systems.

[0440] According to the method, a representative number of test specimens are exposed to heat-moisture action for 7, 14 and 28 days at 70±2° C. and 95±5% relative humidity (RH) in a climatic chamber. Subsequently, the specimens are placed at 23±2° C. and 50±5% RH for at least 24 hours and upon drying are prepared for testing of mechanical performance, like e.g. the delamination strength is measured according to EN 1607:2013, or compression strength according to EN 826:2013 as will be described further below.

[0441] The relative ageing resistance is then calculated in % of and based on the initial absolute value measured at time ‘0’. Results are documented and illustrated for 7, 14 and 28 days of accelerated ageing.

[0442] With respect to the FIGS. 3 to 6 and examples given here, the insulation element 4 is a bonded mineral fibre roof product, commercially available at the assignee or affiliated companies which has been produced with the different binder types mentioned and tested for its mechanical properties. The product in question provides a target density of around 145 kg/m.sup.3 and a loss on ignition (LOI) of approx. 3,8 wt.-%.

[0443] The following Table I shows the delamination strength [kPa] EN 1607 according to FIG. 3.

TABLE-US-00010 TABLE I 0 days 7 days 14 days 28 days A.sub.2 38.6 28.4 27.9 26.9 B.sub.2 32.1 23.7 21.1 15.3 C.sub.2 33.4 25.7 23.5 21.8

[0444] Table I shows the absolute delamination strength of the insulation element 4 according to the disclosure (C.sub.2) compared to an insulation element containing a phenol-formaldehyde binder (A.sub.2) and to an insulation element containing a non-added formaldehyde binder (B.sub.2). The corresponding graphs are shown in FIG. 3.

[0445] The following Table II shows the relative delamination strength according to table I in % of initial according to FIG. 4.

TABLE-US-00011 TABLE II 0 days 7 days 14 days 28 days A.sub.3 100.0 73.6 72.1 68.7 B.sub.3 100.0 75.2 67.1 48.3 C.sub.3 100.0 77.5 71.1 66.2

[0446] Table I shows the relative delamination strength of the insulation element 4 according to the disclosure (C.sub.3) compared to an insulation element containing a phenol-formaldehyde binder (A.sub.3) and to an insulation element containing a non-added formaldehyde binder (B.sub.3). The corresponding graphs are shown in FIG. 4.

[0447] In Tables I and II it can be seen that the delamination strength of the insulation element 4 according to the disclosure is very close to the delamination strength of the insulation element containing a phenol-formaldehyde binder. Furthermore, it can be seen that the loss of delamination strength of the insulation element containing a non-added formaldehyde binder increases much more than the delamination strength of the insulation element 4 according to the disclosure. Furthermore, the delamination strength of the insulation element 4 according to the disclosure is very close to the delamination strength of the insulation element containing a phenol-formaldehyde binder. From FIGS. 3 and 4 it can be seen that the graphs C.sub.2/C.sub.3 and A.sub.2/A.sub.3 are approximately parallel to each other.

[0448] From Table II and FIG. 4 the relative delamination strength of the insulation element 4 according to the disclosure (graph C.sub.3) compared to insulation elements containing a phenol-formaldehyde binder (graph A.sub.3) or insulation elements containing a non-added formaldehyde binder (graph B.sub.3). All insulation elements 4 to be compared were exposed to an ageing process according the before standing description.

[0449] Furthermore, it can be seen from Table II and from FIG. 4, that the values of delamination of the insulation element 4 according to the disclosure are approximately equal to the values of delamination of the insulation element containing phenol-formaldehyde binder A.sub.3.

[0450] The following Table III shows the absolute compression strength [kPa] EN 826 according to FIG. 5.

TABLE-US-00012 TABLE III 0 days 7 days 14 days 28 days A.sub.4 82.6 65.5 63.9 61.3 B.sub.4 66.3 55.1 51.4 43.9 C.sub.4 71.5 58.5 56.1 54.0

[0451] Table III shows the absolute compression strength of the insulation element 4 according to the disclosure (C.sub.4) compared to an insulation element containing a phenol-formaldehyde binder (A.sub.4) and to an insulation element containing a non-added formaldehyde binder (B.sub.4). The corresponding graphs are shown in FIG. 5.

[0452] FIG. 5 shows the compression strength of an insulation element 4 according to the disclosure (graph C.sub.4) compared with the compression strength of an insulation element containing mineral fibres and a non-added formaldehyde binder shown in graph B.sub.4 and the compression strength of an insulation element containing mineral fibres and a phenol-formaldehyde binder shown in graph A.sub.4.

[0453] The compression strength is measured according to EN 826 and it can be seen, that the compression strength is measured immediately after production of the insulation element 4 , and seven, fourteen and twenty-eight days after production of the insulation element 4.

[0454] Whereas the compression strength of the insulation element 4 according to the disclosure is very close to the compression strength of the insulation element containing a phenol-formaldehyde binder (A.sub.4) it can be seen that the loss of compression strength of the insulation element containing a non-added formaldehyde binder (B.sub.4) increases much more than the compression strength of the insulation element 4 according to the disclosure. Furthermore, the compression strength of the insulation element 4 according to the disclosure is very close to the compression strength of the insulation element containing a phenol-formaldehyde binder (A.sub.4). It can be seen that the graphs C.sub.2 and A.sub.2 are approximately parallel to each other.

[0455] The following Table IV shows the relative compression strength according to table III in % of initial according to FIG. 6.

TABLE-US-00013 TABLE IV 0 days 7 days 14 days 28 days A.sub.5 100.0 80.5 78.5 75.2 B.sub.5 100.0 83.2 77.8 66.6 C.sub.5 100.0 82.5 79.0 76.1

[0456] Table IV shows the relative compression strength of the insulation element 4 according to the disclosure (C.sub.5) compared to an insulation element containing a phenol-formaldehyde binder (A.sub.5) and to an insulation element containing a non-added formaldehyde binder (B.sub.5). The corresponding graphs are shown in FIG. 6.

[0457] From FIG. 6 the relative compression strength of the insulation element 4 according to the disclosure (graph C.sub.5) compared to insulation elements containing a phenol-formaldehyde binder (graph A.sub.5) or insulation elements containing a non-added formaldehyde binder (graph B.sub.5). All insulation elements to be compared were exposed to an ageing process containing the steps as described before.

[0458] Furthermore, it can be seen from FIG. 6, that the values of compression strength of the insulation element 4 according to the disclosure are approximately equal to the values of compression strength of the insulation element containing phenol-formaldehyde binder.

[0459] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are inter-changeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.