Method for producing a laminate from wood and a curable composition

Abstract

The invention relates to a method for producing a laminate, characterized in, characterized in that - a wooden body is provided, - a curable composition in the liquid state is applied to the latter, and - the composition cures, the composition containing at least one organic binder and at least 80 % by weight of mineral fillers based on the entire composition. The method enables the permanent joining of wooden bodies and compositions based on an organic binder and having a high content of mineral fillers. The laminates obtained from the method are comparatively light, stable and robust and are especially suitable as sustainable components for building construction, particularly as a ceiling element.

Description

[0001] METHOD FOR PRODUCING A LAYERED BODY FROM WOOD AND A HARDENABLE COMPOSITION

[0002] Technical area

[0003] The invention relates to a method for producing a laminated body, a laminated body and its use as a component in building construction.

[0004] State of the art

[0005] Wood, a renewable resource, has been used as a building material since ancient times. In addition to its sustainability, it offers additional advantages over mineral building materials such as concrete, particularly high tensile strength with low density and appealing aesthetics. The disadvantages of wood as a building material primarily lie in its lack of fire resistance and acoustic conductivity, which makes fire and sound insulation complex, as well as its swelling and shrinkage behavior under the influence of moisture. Combining wood with a mineral building material as a hybrid system can combine the advantages of both materials, with the wood absorbing the tensile forces and the mineral absorbing the compressive forces.For example, this can be used for ceiling structures that have a high load-bearing capacity and flexural rigidity with a relatively low dead weight and low overall height, and can therefore also be used for large spans while maintaining good fire and sound insulation properties. To achieve such properties, it is crucial to join the fundamentally different materials, wood and mineral building materials, together using a suitable joining method that is as shear-resistant and durable as possible. This has been attempted several times in the prior art.

[0006] The typical procedure for joining wood to a mineral building material such as concrete consists of mechanically connecting a hardened concrete body to the wood using metallic fastening systems such as screws, bolts, clamps or anchors. While such connections are stable and resilient, they are complex to manufacture and often visually unsatisfactory. Another option is to create a mechanically stable interlock with the concrete by means of notches or slots in the wood, for example by allowing the liquid concrete to harden in contact with the wood body. However, such connections often lack sufficient stability and durability, not least due to movement in the wood caused by shrinkage or expansion due to changes in humidity or mechanical stress. Gluing wood to hardened concrete is also known.However, bonding typically requires complex pre-treatment of the concrete surface, in which the cement skin on the concrete surface is mechanically removed in order to prevent curing problems of the adhesive and to ensure a stable, resilient bond.

[0007] WO 99 / 02796 and M. Brunner et al., Materials and Structures (2007) 40:119-126 describe the bonding of wood to concrete using an adhesive in a wet-on-wet process and the difficulties encountered. The resulting laminates often break at the adhesive interfaces under mechanical stress or due to the swelling and shrinkage behavior of the wood under changing humidity. Furthermore, the curing reaction of the adhesive is often disrupted by the fresh concrete to such an extent that sufficient adhesive forces are not built up, thus preventing a resilient and / or permanent bond.

[0008] Description of the invention

[0009] The object of the present invention is to provide a hybrid system containing wood and a mineral building material which is easy to produce, is suitable as a building element in building construction and overcomes the disadvantages of the prior art.

[0010] Surprisingly, this object is achieved by a method for producing a laminated body as described in claim 1. A wooden body is coated with a liquid-applied curable composition containing at least one organic binder, preferably based on epoxy resin or polyisocyanate, and at least 80% by weight of mineral fillers.

[0011] The inventive method is simple and quick to implement. The liquid-applied composition hardens quickly, exhibits minimal shrinkage, can be loaded quickly, and does not release moisture or humidity like cement-based mineral building materials. Even without complex pretreatment of the wood surface, the cured composition adheres excellently to the wood. The resulting laminated body is mechanically resilient and impact-resistant. Even with a thin layer of the applied composition and without reinforcement with steel, fabrics, or fibers, it exhibits high compressive strength and high vibration stiffness. Furthermore, it exhibits a low coefficient of thermal expansion, good thermal insulation properties, is not sensitive to corrosion, and is particularly resistant to the effects of moisture or frost, with the water-impermeable cured composition virtually impregnating the wood.

[0012] The inventive method enables the production of laminated bodies that are outstandingly suitable as sustainable components in building construction, particularly as ceiling elements, where high demands are placed on aesthetics, sound insulation, strength, and durability. Furthermore, the inventive method enables the use of hardwood in construction, which is often unsuitable due to its high tendency to absorb water compared to spruce, particularly in combination with fresh concrete. The composition used in the inventive method also acts as a moisture barrier and protects the wooden side of the laminated body from water penetrating from above. The laminated bodies obtained from the method are comparatively light, stable, and resilient and are particularly suitable as sustainable components in building construction, particularly as ceiling elements.

[0013] Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims.

[0014] Ways to implement the invention

[0015] The invention relates to a method for producing a laminated body, characterized in that

[0016] - a wooden body is prepared,

[0017] - a curable composition in liquid state is applied to it

[0018] - and the composition cures, wherein the composition contains at least one organic binder and at least 80% by weight of mineral fillers based on the total composition.

[0019] A “mineral filler” is a powdered or granular inorganic material.

[0020] "Slag" is a glassy or crystalline solidified material that arises as a byproduct, particularly during metal extraction in ore smelting, metal recycling, or waste incineration. In crushed form, it is suitable as a mineral filler. It is a mixture of substances whose main components are CaO, SiO2, Al2O3, MgO, and FeO. Substance names beginning with "poly," such as polyamine or polyol, refer to substances that formally contain two or more of the functional groups mentioned in their name per molecule.

[0021] The hydrogen atoms of primary and secondary amino groups are referred to as “Am in hydrogen”.

[0022] "Molecular weight" refers to the molar mass (in grams per mole) of a molecule. "Mean molecular weight" refers to the number average Mn of a polydisperse mixture of oligomeric or polymeric molecules, which is usually determined by gel permeation chromatography (GPC) against polystyrene as a standard.

[0023] “Storage-stable” means a composition that can be stored at room temperature in a suitable container for a prolonged period, typically for at least 3 months up to 6 months or more, without being altered by storage to an extent relevant to its use.

[0024] The “pot life” of a curable composition is the maximum period of time between mixing the components and application during which the mixed composition is in a sufficiently flowable state and can wet the wood surface well.

[0025] "Room temperature" is defined as 23°C. All industry standards and norms mentioned in this document refer to the versions valid at the time of filing the initial application, unless otherwise stated.

[0026] Percentages by weight (% by weight) refer to the mass fraction of a component of a composition relative to the total composition, unless otherwise stated. The terms "mass" and "weight" are used synonymously in this document.

[0027] The wood body is preferably made of hardwood or softwood, preferably beech or spruce. These wood species are mechanically resilient and widely used in construction.

[0028] The wooden body is made of beechwood, which is widely available and particularly hard and resilient. However, due to its high swelling capacity under the influence of moisture, it has so far been used relatively rarely as a building material.

[0029] All types of shaped wooden bodies are suitable as wooden bodies. Shaped bodies with at least one flat surface are preferred.

[0030] The wooden body is preferably laid out in such a way that a horizontal, flat surface is placed on top, hereinafter also referred to as the "top side".

[0031] The wooden body preferably has the shape of a cube or a cuboid, in particular a cuboid. In the case of a cuboid, it is preferably positioned so that one of the largest surfaces is at the top, thus forming the upper side. The side perpendicular to the upper side is also referred to below as the "thickness."

[0032] The wooden body preferably has a thickness in the range of 10 to 300 mm, preferably 20 to 200 mm. The thickness of the wooden body (H) is shown as an example in Figure 1, designated DH.

[0033] The top side of the wooden body preferably has a length in the range of 0.3 to 20 m, particularly preferably 1 to 10 m. The length of the wooden body (H) is shown by way of example in Figure 1 as L. The top side of the wooden body preferably has a width in the range of 50 to 2,000 mm, preferably 100 to 1,500 mm, in particular 150 to 1,000 mm. The width of the wooden body (H) is shown by way of example in Figure 1 as B. The wooden body preferably has the shape of a cuboid, wherein the length is greater than the width and the width is greater than the thickness. Such a wooden body can also be referred to as a board, beam or slat.

[0034] The wooden body can be made of unglued solid wood.

[0035] The wood body is preferably made of glued and / or interlocked laminated timber or laminated slats. This allows for large wood bodies with high mechanical strength and dimensional stability, especially wood bodies 1 m or more in length and 150 mm or more in width.

[0036] Preferably, the wood is in a dry, stored state, as is typical for use as a building material.

[0037] The wood body can be pretreated before applying the curable composition. Preferably, the wood body should be cleaned of dust.

[0038] Mechanical pretreatment in the form of roughening or milling grooves or slots is possible, but is not necessary for a good connection and is therefore not preferred.

[0039] Pretreatment with activators or primers is possible. However, especially for a curable epoxy resin-based composition, pretreatment with activators or primers is not necessary for good adhesion.

[0040] When applying the liquid, curable composition, the wooden body is preferably provided with formwork elements on the outer sides, for example in extension of the side edges, so that the composition remains on the wooden body after application and cannot flow off. Figure 1 shows an example of the thickness DH of the wooden body (H). The formwork elements are preferably attached such that they enclose the thickness DH of the wooden body all the way around and protrude upwards far enough that they form a complete formwork when the resulting volume is completely filled with the liquid composition. The height of the formwork elements preferably corresponds to the thickness D of the laminated body, as shown by way of example in Figure 1.

[0041] Suitable formwork elements are boards or other devices which are removed after the hardening of the hardenable composition, as is usual in concrete construction.

[0042] Preferably, the curable composition comprises at least two separately packaged components which are mixed before or during application of the liquid composition.

[0043] Preferably, the curable composition is free of cement.

[0044] During application, the liquid composition preferably has a largely self-leveling, easily pourable consistency in order to thoroughly wet the surface of the wooden body.

[0045] During application, the preferably installed formwork elements prevent the applied composition from flowing away. The formwork elements, together with the upper surface of the wooden body, preferably form a mold, with the upper surface of the wooden body forming the base. The formwork elements preferably extend far enough beyond the upper surface of the wooden body that the depth of the mold corresponds to the desired layer thickness of the curable composition.

[0046] The curable composition is preferably applied in a layer thickness in the range of 10 to 300 mm, preferably 20 to 200 mm, in particular 30 to 100 mm. The layer thickness of the curable composition (Z) is shown as an example in Figure 1, designated Dz.

[0047] The curable composition is preferably applied to create a horizontal surface. If necessary, the surface of the composition is smoothed toward the end of application, for example, using a spatula or trowel. Additionally, a spiked roller can be used to pierce and eliminate any air bubbles present on the surface.

[0048] Preferably, the curable composition is applied within the pot life.

[0049] The applied curable composition is then cured.

[0050] The composition preferably cures at ambient temperature, possibly with exposure to moisture. The organic binder crosslinks through chemical reactions of the reactive groups it contains. The duration of the curing process depends on the ambient conditions and the ingredients used in the curable composition. Typically, existing formwork elements are removed after approximately 12 to 24 hours, and the composite reaches its final strength after a few days to weeks at room temperature.

[0051] All types of organic binders are suitable as organic binders for the curable composition, in particular those based on epoxy resins, polyisocyanates, polymers crosslinked via silane groups, unsaturated polyester resins, acrylic resins or other polymers with crosslinkable reactive groups.

[0052] Preferably, the organic binder is distributed between at least two separately packaged, storage-stable components prior to application, wherein the mineral filler may be present at least partially as an additional, separately packaged component. However, it is also possible for the organic binder to be present in only one separately packaged component, wherein in particular some of the reactive groups of the organic binder are present in a blocked form and are released, for example, by hydrolysis during and after application due to the action of moisture, and / or the reactive groups of the organic binder are crosslinked due to the action of moisture, as is particularly the case with polyisocyanates. The organic binder of the curable composition is preferably selected from a) epoxy resins and curing agents for epoxy resins and b) polyisocyanates and crosslinking agents for polyisocyanates.Such compositions enable rapid curing, high adhesive forces on the wood body and good mechanical properties of the resulting laminated body without deformation of the wood body due to shrinkage or incompatibilities.

[0053] In a particularly preferred embodiment of the invention, the organic binder of the curable composition comprises at least one epoxy resin and at least one hardener for epoxy resins. Such a composition enables excellent adhesion of the cured composition to the wood body without requiring pretreatment of the wood surface with activators or primers, thereby making the inventive method particularly easy to implement. Furthermore, such a composition is particularly insensitive to moisture during the process, for example, in the form of high air humidity or increased moisture content of the wood body. This also simplifies the implementation of the method.

[0054] Preferably, such a curable composition comprises

[0055] - a first component containing at least one epoxy resin, in particular selected from bisphenol A diglycidyl ethers, bisphenol F diglycidyl ethers and phenol novolak glycidyl ethers with an average functionality of 2.3 to 3,

[0056] - and a second component containing the hardener for epoxy resins containing at least one polyamine with aliphatically bound amino groups and at least 3 amine hydrogens, and the mineral filler is present as a constituent of the first and / or the second component and / or as a further component.

[0057] Liquid epoxy resins are particularly suitable as epoxy resins. These are technical epoxy resins that flow at room temperature and have a glass transition temperature below 25°C. These are obtained in a known manner, in particular from the glycidylation of compounds with at least two active hydrogen atoms, especially polyphenols, polyols, or amines, by reaction with epichlorohydrin.

[0058] Suitable epoxy resins are in particular aromatic epoxy liquid resins, especially the glycidyl ethers of

[0059] - Bisphenol A, bisphenol F, or bisphenol A / F, where A stands for acetone and F for formaldehyde, which served as starting materials for the production of these bisphenols. In the case of bisphenol F, positional isomers may also be present, particularly those derived from 2,4'- or 2,2'-hydroxyphenylmethane.

[0060] - Dihydroxybenzene derivatives such as resorcinol, hydroquinone or pyrocatechol;

[0061] - weiteren Bisphenolen oder Polyphenolen wie Bis(4-hydroxy-3-methylphenyl)- methan, 2,2-Bis(4-hydroxy-3-methylphenyl)propan (Bisphenol-C), Bis(3,5-di- methyl-4-hydroxyphenyl)methan, 2,2-Bis(3,5-dimethyl-4-hydroxyphenyl)propan, 2,2-Bis(3,5-dibromo-4-hydroxyphenyl)propan, 2,2-Bis(4-hydroxy-3-tert.butyl- phenyl)propan, 2,2-Bis(4-hydroxyphenyl)butan (Bisphenol-B), 3,3-Bis(4-hydro- xyphenyl)pentan, 3,4-Bis(4-hydroxyphenyl)hexan, 4,4-Bis(4-hydroxyphenyl)- heptan, 2,4-Bis(4-hydroxyphenyl)-2-methylbutan, 2,4-Bis(3,5-dimethyl-4-hydro- xyphenyl)-2-methylbutan, 1 ,1-Bis(4-hydroxyphenyl)cyclohexan (Bisphenol-Z),

[0062] 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-hydroxy-naphth-1-yl)methane, bis(4-hydroxynaphth-1-yl)methane, 1,5-dihydroxynaphthalene, Tris(4-hydroxyphenyl)methane, 1, 1,2,2-T etrakis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)ether or Bis(4-hydroxyphenyl)sulfone;

[0063] - novolaks, which are in particular condensation products of phenol or cresols with formaldehyde or paraformaldehyde or acetaldehyde or crotonaldehyde or isobutyraldehyde or 2-ethylhexanal or benzaldehyde or furfural;

[0064] - 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). Other possible epoxy resins are aliphatic or cycloaliphatic polyepoxides, especially

[0065] - Glycidyl ethers of saturated or unsaturated, branched or unbranched, cyclic or open-chain di-, tri- or tetrafunctional C2 to C50 alcohols, in particular ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, polypropylene glycols, dimethylolcyclohexane, neopentyl glycol, dibromoneopentyl glycol, castor oil, trimethylolpropane, trimethylolethane, pentaerythrol, sorbitol or glycerol, or alkoxylated glycerol or alkoxylated trimethylolpropane;

[0066] - a hydrogenated bisphenol A, F or A / F liquid resin, or the glycidylation products of hydrogenated bisphenol A, F or A / F;

[0067] - an N-glycidyl derivative of amides or heterocyclic nitrogen bases, such as triglycidyl cyanurate or triglycidyl isocyanurate, or reaction products of epichlorohydrin with hydantoin.

[0068] Aromatic epoxy liquid resins are preferred, in particular with an average epoxy equivalent weight in the range of 156 to 210 g / eq.

[0069] Preferably, the epoxy resin is selected from bisphenol A diglycidyl ethers, bisphenol F diglycidyl ethers and phenol novolak glycidyl ethers with an average functionality of 2.3 to 3. These have an easily manageable viscosity and enable curable compositions with good processability and high strength and durability after curing.

[0070] Also preferred are epoxy resins based at least partially on renewable raw materials, in particular epoxy resins from the reaction of bio-based hydroxy-functional compounds with bio-based epichlorohydrin. Vanillin-based epoxy resins, such as vanillin alcohol diglycidyl ethers or the glycidyl ethers of bisvanillin derivatives, as well as glycerol-based epoxy resins, such as the glycidyl ethers of glycerol or polyglycerol, are particularly preferred. Such epoxy resins enable particularly sustainable laminates. The first component of this embodiment preferably contains at least one reactive diluent containing epoxy groups, such as in particular butanediol diglycidyl ether, hexanediol diglycidyl ether, trimethylolpropane di- or triglycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, guaiacol glycidyl ether, 4-methoxyphenyl glycidyl ether, pn-butylphenyl glycidyl ether, p-tert.Butylphenyl glycidyl ether, 4-nonylphenyl glycidyl ether, 4-dodecylphenyl glycidyl ether, cardanol glycidyl ether, benzyl glycidyl ether, allyl glycidyl ether, butyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, or glycidyl ethers of natural alcohols, such as, in particular, C5- to C10- or C12- to C14- or C13- to C18-alkyl glycidyl ethers. Preference is given to butanediol diglycidyl ether, hexanediol diglycidyl ether, C12- to C14-alkyl glycidyl ether, or a combination of these reactive diluents.

[0071] The second component of this embodiment containing the hardener for epoxy resins contains at least one polyamine with aliphatically bound amino groups and at least 3 amines in hydrogens.

[0072] Suitable polyamines of this type are in particular N-benzyl-1,2-ethanediamine, N-benzyl-1,2-propanediamine, N-benzyl-1,3-bis(aminomethyl)benzene, N-(2-ethylhexyl)-

[0073] 1.3-bis(aminomethyl)benzol, 2,2-Dimethyl-1 ,3-propandiamin, 1 ,3-Pentandiamin (DAMP), 1 ,5-Pentandiamin, 1 ,5-Diamino-2-methylpentan (MPMD), 2-Butyl-2-ethyl- 1 ,5-pentandiamin (C11-Neodiamin), 1 ,6-Hexandiamin, 2,5-Dimethyl-1 ,6-hexan- diamin, 2,2(4),4-Trimethyl-1 ,6-hexandiamin (TMD), 1 ,7-Heptandiamin, 1 ,8-Octan- diamin, 1 ,9-Nonandiamin, 1 ,10-Decandiamin, 1 ,11-Undecandiamin, 1 ,12-Dodecan- diamin, 1 ,2-, 1 ,3- oder 1 ,4-Diaminocyclohexan, 1 ,3-Bis(aminomethyl)cyclohexan,

[0074] 1.4-Bis(aminomethyl)cyclohexan, Bis(4-aminocyclohexyl)methan, Bis(4-amino-3- methylcyclohexyl)methan, Bis(4-amino-3-ethylcyclohexyl)methan, Bis(4-amino-3,5- dimethylcyclohexyl)methan, Bis(4-amino-3-ethyl-5-methylcyclohexyl)methan, 1 - Amino-3-aminomethyl-3,5,5-trimethylcyclohexan (IPDA), 2(4)-Methyl-1 ,3-diamino- cyclohexan, 2,5(2,6)-Bis(aminomethyl)bicyclo[2.2.1]heptan (NBDA), 3(4),8(9)- Bis(aminomethyl)tricyclo[5.2.1 .0 2 ’ 6]decane, 1,4-diamino-2,2,6-trimethylcyclohexane (TMCDA), 1,8-menthanediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]-undecane, 1,3-bis(aminomethyl)benzene (MXDA), 1,4-bis(aminomethyl)benzene, bis(2-aminoethyl)ether, 3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine, 5,8-dioxadodecane-3,10-diamine, 4,7,10-trioxatridecane-1,13-diamine or higher Oligomers of these diamines, bis(3-aminopropyl)polytetrahydrofurans or other polytetrahydrofurandiamines, polyoxyalkylenedi- or triamines, in particular polyoxypropylenediamines or polyoxypropylenetriamines such as Jeffamine® D-230, Jeffamine® D-400 or Jeffamine® T-403 (all from Huntsman), furan-based amines such as 2,5-bis(aminomethyl)furan, 2,5-bis(aminomethyl)tetrahydrofuran, bis(5-aminomethylfuran-2-yl)methane, bis(5-aminomethyltetrahydrofuran-2-yl)methane, 2,2-bis(5-aminomethylfuran-2-yl)propane or 2,2-bis(5-aminomethyltetrahydrofuran-2-yl)propane,or diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), dipropylenetriamine (DPTA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N,N'-bis(3-aminopropyl)ethylenediamine (N4-amine), N,N'-bis(3-amino- propyl)-1,4-diaminobutane, N5-(3-aminopropyl)-2-methyl-1,5-pentanediamine, N3-(3-aminopentyl)-1,3-pentanediamine, N5-(3-amino-1-ethylpropyl)-2-methyl-1,5-pentanediamine, N,N'-bis(3-amino-1-ethylpropyl)-2-methyl-1 ,5-pentanediamine, 3-(2-amino- ethyl)aminopropylamine, bis(hexamethylene)triamine (BHMT), N-aminoethylpiperazine, 3-dimethylaminopropylamine (DMAPA), 3-(3-(dimethylamino)propylamino)propylamine (DMAPAPA), amine-functional adducts of the above-mentioned amines with epoxides, phenalkamines, which are reaction products of cardanol with aldehydes, in particular formaldehyde, and polyamines, polyamidoamines such as in particular reaction products of a dimer fatty acid with a stoichiometric excess of a polyamine such as in particular DETA,TETA or TEPA.,

[0075] The hardener preferably contains a combination of two or more such polyamines.

[0076] Preferred polyamines are MPMD, TMD, 1,2-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, IPDA, 2(4)-methyl-1,3-diaminocyclohexane, MXDA, DETA, TETA, TEPA, N3-amine, N4-amine, DPTA, polyoxypropylenedi- or -triamines having an average molecular weight Mn in the range from 200 to 500 g / mol or polyamidoamines, and in particular combinations of these amines. Preferably, an epoxy resin-based curable composition contains further ingredients, in particular thinners such as benzyl alcohol or catalysts such as calcium nitrate, sulfonic acids or phenol group-containing amines such as in particular 2,4,6-tris(dimethylaminomethyl)phenol, or other substances commonly used in epoxy resin compositions.

[0077] Preferably, neither the epoxy resin nor the hardener are water-based. Such a curable composition preferably contains only a low water content, preferably less than 5% by weight, in particular less than 1% by weight, based on the total composition. Such a composition is particularly stable after curing.

[0078] Preferably, the components of such an epoxy resin-based composition are mixed in such a ratio that the molar ratio of the amine hydrogens to the epoxy groups is in the range of 0.5 to 1.5, especially 0.7 to 1.2. Such a composition cures quickly and smoothly.

[0079] In a further preferred embodiment of the invention, the organic binder of the curable composition comprises at least one polyisocyanate and at least one crosslinker for polyisocyanates. Such a composition cures particularly quickly, enabling a particularly efficient process.

[0080] Preferably, such a curable composition comprises

[0081] - a first component containing a crosslinker for polyisocyanates containing at least one polyol having an average molecular weight of 250 to 2,000 g / mol and an average OH functionality of 1.7 to 6,

[0082] - and a second component containing at least one polyisocyanate, and the mineral filler is present as a constituent of the first and / or the second component and / or as a further component.

[0083] Polyols that are liquid at room temperature are preferred. Commercially available polyols such as those commonly used for polyurethane compositions are preferred, in particular polyether polyols, polyester polyols, polycarbonate polyols, polyacrylate polyols, polyols derived from natural fats or oils, such as castor oil or reaction products of castor oil with ketone resins, polyhydrocarbon polyols such as polybutadiene polyols, and combinations of such polyols.

[0084] Polyols with an average molecular weight of 250 to 1,000 g / mol are preferred.

[0085] Polyols with an average OH functionality of 1.8 to 4 are preferred.

[0086] The first component preferably contains at least one further crosslinker, such as in particular 1,2-ethanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,7-heptanediol, 1,8-octanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol or triethylene glycol, or further di- or polyfunctional alcohols such as in particular ethoxylated bisphenol A, propoxylated bisphenol A, cyclohexanediol, hydrogenated bisphenol A, dimer fatty acid alcohols, 1,1,1-trimethylolethane, 1,1 ,1-Trimethylolpropane, glycerol, pentaerythritol, sugar alcohols such as in particular xylitol, sorbitol or mannitol or sugars such as in particular sucrose or alkoxylated derivatives of the above-mentioned alcohols or mixtures of the above-mentioned alcohols.

[0087] Furthermore, the first component may contain further crosslinking agents, such as, in particular, compounds containing amine groups or di- or multifunctional aldimines or ketimines.

[0088] Particularly suitable as polyisocyanates are diisocyanates, oligomers or polymers or derivatives of diisocyanates, isocyanate group-containing reaction products of diisocyanates with polyols or combinations thereof.

[0089] Suitable diisocyanates are in particular toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), mixtures of MDI and MDI homologues (polymeric MDI or PMDI), 1,6-hexane diisocyanate (HDI), 2,2(4),4-trimethyl-1,6-hexane diisocyanate (TMDI), 1-methyl-2,4(6)-diisocyanatocyclohexane (HeTDI), isophorone diisocyanate (IPDI) or perhydrodiphenylmethane diisocyanate (H12MDI).

[0090] The polyisocyanate is preferably a room-temperature liquid form of MDI, especially a polymeric MDI, a partially carbodiimidized MDI, or a grade of MDI with a high 2,4'-MDI content. These polyisocyanates are easy to process and / or enable particularly high strengths.

[0091] A polyisocyanate-based curable composition preferably contains further ingredients, in particular solvents or thinners, catalysts for the crosslinking reaction, drying agents such as molecular sieves, adhesion promoters such as in particular silanes or titanates, or other substances commonly used in polyurethane compositions.

[0092] A polyisocyanate-based curable composition may contain a small amount of water, particularly from 0.005 to 0.1% by weight of water based on the total composition. This can result in a certain foaming of the composition upon curing, which can positively influence the properties of the laminate. The water can be present as part of the first component or added in another form during mixing of the components.

[0093] Preferably, the components of such a polyisocyanate-based composition are mixed in such a ratio that the molar ratio of the hydroxyl groups and any other isocyanate-reactive groups present to the isocyanate groups is in the range of 0.7 to 1.1, preferably 0.8 to 1.0. Such a composition cures quickly and smoothly.

[0094] In all embodiments, the curable composition contains at least 80% by weight of mineral fillers. These can be present as a separate component and mixed with the rest of the composition before or during application, and / or they can be pre-mixed with other components of the composition.

[0095] In the case of the previously described epoxy resin-based or polyisocyanate-based compositions comprising a first and a second component, the mineral fillers are present as a component of the first and / or the second component and / or further component.

[0096] Preferably, at least some of the mineral fillers are present as a separate, third component and optionally also as a further, fourth component.

[0097] The curable composition preferably contains at least 85% by weight of mineral fillers based on the total composition. This allows for particularly low heat release during curing and particularly low shrinkage during curing, which prevents warping of the laminate.

[0098] Particularly suitable mineral fillers include quartz flour, quartz sand, limestone sand, river sand, aggregate, slag, calcium carbonate, chalk, barite, dolomite, wollastonite, talc, titanium dioxide, iron oxides, calcined silica, clay minerals, pumice, perlite, limestone, limestone flour, silica fume, aluminum oxide, cement, fly ash, metakaolin, silica fume, calcium sulfate, or a combination thereof. Shapes and sizes can vary from fine flour to sand particles or gravel to large, coarse stones.

[0099] In case the curable composition contains hydraulic binders such as cement, these are present as fillers and the composition cures even without them.

[0100] Preferably, the curable composition is free of cement.

[0101] Quartz and / or slag are preferred as mineral fillers.

[0102] The hardenable composition preferably contains at least 50% by weight of mineral fillers selected from quartz and slag, based on the total composition. Such a composition is easy to process and enables particularly high strengths.

[0103] The curable composition may contain other ingredients, in particular

[0104] - fibres, in particular glass fibres, carbon fibres, metal fibres, ceramic fibres or plastic fibres such as polyamide fibres or polyethylene fibres,

[0105] - Rheology modifiers, especially thickeners,

[0106] - surface-active additives, in particular defoamers, deaerators, wetting agents, dispersing agents or leveling agents, or

[0107] - Stabilizers against oxidation, heat, light or UV radiation or biocides.

[0108] In a preferred embodiment of the invention, at least some of the mineral fillers are coated with at least one dispersant, in particular a polycarboxylate ether. This enables particularly good flowability of the curable composition even with a high mineral filler content, and thus also particularly low exothermicity during curing and particularly high strength of the cured composition.

[0109] Preferred are polycarboxylate ethers in the form of comb polymers containing carboxylic acid groups and / or salts thereof and poly(oxyalkylene) side chains. Such polycarboxylate ethers are known as plasticizers for mortar, for example, and are commercially available, for example under the brand name Viscocrete® (from Sika).

[0110] To coat the mineral fillers, the dispersant can be sprayed on or, if necessary in diluted form, mixed with the mineral fillers.

[0111] The invention further relates to a laminated body obtained by the process according to the invention. The laminated body comprises a wood layer and a layer consisting of the described cured composition. In particular, the laminated body consists of a) the wood layer and b) the layer consisting of the cured composition.

[0112] The laminated body preferably has the shape of a cuboid.

[0113] Figure 1 shows an example of a laminated body as described above. This comprises a wood layer (H) and a layer of the described composition (Z).

[0114] Preferably, the underside of the cuboid forms the wood side, and the top of the cuboid forms the cured composition. The thickness of the wood layer is preferably equal to or greater than the thickness of the composition. Figure 1 shows, by way of example, the thickness (DH) of the wood layer (H) and the thickness (Dz) of the composition (Z).

[0115] Preferably, the dimensions of the laminated body are such that the wood layer is able to support the layer of the applied composition without being bent to any significant extent under its weight if no support, reinforcement or armouring is provided.

[0116] The laminated body preferably has a load-bearing capacity of at least 100 kN, preferably at least 120 kN, determined on a laminated body of dimension 5200 x 320 x 180 mm made of wood and the cured composition, wherein the wood layer has the dimension 5200 x 320 x 120 mm and the cured composition has the dimension 5200 x 320 x 60 mm, by means of 4-point bending with two pressure cylinders with a test span of 5000 mm, distance of the pressure cylinders from the support 1680 mm in each case and distance between the pressure cylinders 1640 mm.

[0117] The maximum deformation is preferably in the range of 70 to 250 mm, in particular 100 to 200 mm.

[0118] Preferably, the stiffness of the composite cross-section is at least 10 9 N / mm 2 , especially 10 11 N / mm 2The composite body is stable and durable. It can be transported freely in space without permanently bending. It can be stacked and exposed to heat, moisture, or UV light without significant loss of strength.

[0119] The laminated body can also be referred to as a board, beam, batten or sandwich element.

[0120] The laminated article differs from a bonded article. In the laminated article according to the invention, the cured composition is in contact with the wood layer on only one side. In an article bonded with a cured composition, however, the composition is arranged between at least two substrates with which the composition is in contact and which are bonded by means of the composition.

[0121] A further object of the invention is the use of the laminated body as a component in building construction, in particular as a ceiling element. As a ceiling element, the laminated body is installed in such a way that the wooden side forms the visible ceiling, as seen from the room, and the side of the cured composition faces the roof or an overlying floor.

[0122] The laminated body produced by the process according to the invention enables the installation of structurally load-bearing wooden ceilings that are particularly sound-insulating, thermally insulating and stable, require no hydraulic binders and only a small amount of aggregates, and are therefore particularly sustainable.

[0123] Examples

[0124] The following are exemplary embodiments intended to further illustrate the described invention. Of course, the invention is not limited to these described exemplary embodiments.

[0125] A "standard climate" (NC) is defined as a temperature of 23±1 °C and a relative humidity of 50±5%. The beechwood used was beech laminated timber and was supplied by Fagus Suisse SA. The curable compounds used:

[0126] Composition Z1 (epoxy resin based):

[0127] Sikadur® 42 LE Plus Component A (from Sika), reactively diluted epoxy resin based on bisphenol A / F diglycidyl ether.

[0128] Sikadur® 42 LE Plus Component B (from Sika), hardener for epoxy resins containing isophoronediamine, polyetheramine, triethylenetetramine and benzyl alcohol.

[0129] Sikadur® 42 LE Plus Component C (from Sika), mixture of mineral fillers containing approx. 75% by weight quartz.

[0130] For application, the liquid components A and B and the powder component C were mixed in the weight ratio A:B:C = 3:1:32 and processed within 60 minutes.

[0131] Composition Z2 (epoxy resin based):

[0132] Sikadur® 42 LE Plus Component A (from Sika), reactively diluted epoxy resin based on bisphenol A / F diglycidyl ether.

[0133] Sikadur® 42 LE Plus Component B (from Sika), hardener for epoxy resins containing isophoronediamine, polyetheramine, triethylenetetramine and benzyl alcohol.

[0134] Sikadur® 42 LE Plus Component C (from Sika), mixture of mineral fillers containing approx. 75% by weight quartz.

[0135] Quartz sand 2.0 to 3.2 mm, abbreviated as "QS".

[0136] For the application, the liquid components A and B, the powder component C and the quartz sand QS were mixed in the weight ratio A:B:C:QS = 3:1 :22:11 and processed within 60 minutes.

[0137] Composition Z3 (polyisocyanate-based):

[0138] SikaBiresin® F50 Component A (from Sika), polyol mixture with approx. 25 wt% aluminum hydroxide and approx. 5 wt% molecular sieve.

[0139] SikaBiresin® F50 Component B (from Sika), liquid MDI. Sikadur® 514 Plus Component C (from Sika), a mixture of mineral fillers containing approximately 70% quartz and approximately 15% Portland cement by weight.

[0140] For application, the liquid components A and B and the powder component C were mixed in the weight ratio A:B:C = 2:1:20 and processed within 30 minutes.

[0141] Composition Z4 (polyisocyanate-based):

[0142] SikaBiresin® F50 Component A (from Sika), polyol mixture with approx. 25 wt% aluminum hydroxide and approx. 5 wt% molecular sieve.

[0143] SikaBiresin® F50 Component B (from Sika), liquid MDI.

[0144] Sikadur® 514 Plus Component C (from Sika), mixture of mineral fillers containing approx. 70% by weight quartz and approx. 15% by weight Portland cement.

[0145] Quartz sand 2.0 to 3.2 mm, abbreviated as "QS".

[0146] For the application, the liquid components A and B, the powder component C and the quartz sand QS were mixed in the weight ratio A:B:C:QS = 2:1:14:7 and processed within 30 minutes.

[0147] Production of laminated bodies:

[0148] Example 1 :

[0149] Several laminated bodies were produced under standard conditions by placing a 40 x 50 x 30 mm beechwood body on a horizontal support so that a 40 x 50 mm surface was facing upwards and the thickness was 30 mm. The surface was dusted using a brush.

[0150] The wooden body thus prepared was then clamped into a formwork mold that completely surrounded the outer sides of the wooden body and projected 30 mm above the surface of the wooden body, creating a casting mold for the hardenable composition with a depth of 30 mm.

[0151] The freshly mixed composition Z1 was then poured into the mold in a layer thickness of 30 mm, completely filling the mold, and the surface was smoothed with a trowel. After 12 hours in standard conditions, the formwork was removed. A composite body measuring 40 x 50 x 60 mm was obtained.

[0152] Several such laminates were subjected to a compressive shear strength test after storage for 28 days under standard conditions. The compressive shear strength was determined in accordance with DIN EN 392 on the bonded shear area of ​​50 x 40 mm at a test speed of 1 mm / s.

[0153] Further such composites were stored in water for 28 days in standard climate and then for 24 hours at room temperature and were also subjected to the compressive shear strength test in the wet state.

[0154] Example 1 showed a compressive shear strength of 18 MPa (average of 5 laminated bodies) after 28 days of storage in standard climate, with the fracture occurring predominantly in the wood layer.

[0155] After 24 hours of immersion in water, the wood layer in each case swelled significantly (volume increase of approximately 30%), but the laminates were otherwise intact. The compressive shear strength of the wet laminates was 7 MPa (average of 5 laminates), with failure occurring at the interface between composition Z1 and the wood.

[0156] Examples 2 and 3:

[0157] In standard climate, several laminated bodies were produced by positioning a wooden body made of beech wood measuring 1020 x 60 x 30 mm on a horizontal base in such a way that an area of ​​1020 x 60 mm was facing upwards and the thickness was 30 mm.

[0158] For Example 2, the wood surface was dusted using a brush and then the freshly mixed composition Z1 was added to the mold in a layer thickness of 30 mm so that it was completely filled, and the surface was smoothed using a trowel.

[0159] For Example 3, the wood surface was pretreated with Sika® Primer MR Fast (a water-based two-component epoxy primer from Sika). After a flash-off time of 24 hours, the freshly mixed composition Z3 was poured into the mold in a layer thickness of 30 mm, completely filling it, and the surface was smoothed with a trowel.

[0160] After 12 hours in standard conditions, the formwork was removed. A composite body measuring 1020 x 60 x 60 mm was obtained, made of beech wood and the cured composite.

[0161] After storage for 28 days under standard conditions, several such laminated bodies were subjected to a 3-point bending test according to DIN 512186 with a span of 900 mm, a preload of 5 N, and a test speed of 5 mm / min. The flexural strength and maximum deformation were determined. To determine the modulus of elasticity, additional such laminated bodies were subjected to the same test, with a test speed of 2 mm / min and a load range of 100 to 3200 N.

[0162] The results are shown in Table 1.

[0163] For comparison (reference), an uncoated wooden body made of beech wood with dimensions of 1020 x 60 x 60 mm was subjected to the same tests and the results are also given in Table 1.

[0164] Table 1 : Results of the 3-point bending of examples 2, 3 and reference

[0165] Examples 4 and 5:

[0166] Under standard conditions, laminated timber bodies were manufactured by positioning a 5200 x 320 x 120 mm laminated timber beam made of glued beech square timber (approx. 2000 x 40 x 40 mm) on a horizontal support so that a surface of 5200 x 320 mm was exposed at the top and the thickness was 120 mm. A formwork was mounted around the wooden beam, creating a 60 mm deep mold on the surface.

[0167] For Example 4, the wood surface was dusted using a brush and then the freshly mixed composition Z2 was added to the casting mold in a layer thickness of 60 mm so that it was completely filled, and the surface was smoothed using a trowel.

[0168] For Example 5, the wood surface was pretreated with Sika® Primer MR Fast (a water-based two-component epoxy primer from Sika). After a flash-off time of 24 hours, the freshly mixed composition Z4 was poured into the mold in a layer thickness of 60 mm, completely filling it, and the surface was smoothed with a trowel.

[0169] After 12 hours in standard conditions, the formwork was removed. A composite measuring 5200 x 320 x 180 mm was obtained, made of beech wood and the cured composite, without any distortion in length, width, or height. In particular, the composite exhibited no shrinkage cracks or warping due to shrinkage in the curable composite, also known as "cupping," or any detachment of the composite from the wood surface after curing.

[0170] After storage for 28 days under standard conditions, several such composites were subjected to a four-point bending test using two compression cylinders over a test span of 5000 mm. The distance between the compression cylinders and the support was 1680 mm, and the distance between the compression cylinders was thus 1640 mm. The measured force-deformation relationship at the center of the beam was used to determine the flexural rigidity of the composite cross-section (stiffness), the ultimate load, and the maximum deformation at failure (average of two composites). The results are presented in Table 2.

[0171]

[0172] Table 2: Results of the 4-point bending of examples 4 and 5

Claims

Patent claims:

1. A method for producing a layered body, characterized in that - a wooden body is prepared - a curable composition in liquid state is applied to it - and the composition hardens, wherein the composition contains at least one organic binder and at least 80% by weight of mineral fillers based on the total composition.

2. Method according to claim 1, characterized in that the curable composition comprises at least two separately packaged components which are mixed before or during the application of the liquid composition.

3. Method according to one of claims 1 or 2, characterized in that the curable composition is free of cement.

4. Method according to one of claims 1 to 3, characterized in that the wooden body consists of glued and / or interlocked laminated timber or blockboard.

5. Method according to one of claims 1 to 4, characterized in that the wooden body has a thickness in the range of 10 to 300 mm, preferably 20 to 200 mm.

6. Method according to one of claims 1 to 5, characterized in that the wooden body is provided with formwork elements on the outer sides when the liquid curable composition is applied, so that the composition remains on the wooden body after application and cannot run off.

7. Method according to one of claims 1 to 6, characterized in that the curable composition is applied in a layer thickness in the range of 10 to 300 mm, preferably 20 to 200 mm, in particular 30 to 100 mm.

8. Method according to one of claims 1 to 7, characterized in that the curing of the composition takes place at ambient temperature, optionally under the influence of moisture.

9. Method according to any one of claims 1 to 8, characterized in that the organic binder of the curable composition is selected from a) epoxy resins and hardeners for epoxy resins and b) polyisocyanates and crosslinkers for polyisocyanates.

10. Method according to any one of claims 2 to 9, characterized in that the curable composition - a first component comprising at least one epoxy resin, in particular selected from bisphenol A diglycidyl ethers, bisphenol F diglycidyl ethers and phenol novolac glycidyl ethers with an average functionality of 2.3 to 3, - and a second component comprising the hardener for epoxy resins containing at least one polyamine with aliphatic amino groups and at least 3 hydrogen amines, and the mineral filler is present as a component of the first and / or the second component and / or as a further component.

11. Method according to any one of claims 2 to 9, characterized in that the curable composition - a first component containing a crosslinker for polyisocyanates containing at least one polyol with an average molecular weight of 250 to 2,000 g / mol and an average OH functionality of 1.7 to 6, - and a second component containing at least one polyisocyanate The process comprises a mineral filler present as a component of the first and / or the second component and / or as a further component. A process according to any one of claims 1 to 11, characterized in that the curable composition contains at least 50% by weight of mineral fillers selected from quartz and slag, based on the total composition. Layered bodies obtained from the process according to any one of claims 1 to 12.A layered body according to claim 13, characterized in that it has a load-bearing capacity of at least 100 kN, determined on a layered body of dimensions 5200 x 320 x 180 mm made of wood and the cured composition, wherein the wood layer has dimensions 5200 x 320 x 120 mm and the cured composition has dimensions 5200 x 320 x 60 mm, by means of 4-point bending with two pressure cylinders at a test span of 5000 mm, distance of the pressure cylinders from the support 1680 mm and distance between the pressure cylinders 1640 mm. Use of the layered body according to one of claims 13 or 14 as a component in building construction, in particular as a ceiling element.

Images