Composite components with improved properties

Abstract

The present invention relates to a composite element having the following layer structure: 2 to 20 mm of metal, 10 to 100 mm of a compact polyurethane formulation, and an additional 2 to 20 mm of metal. The polyurethane formulation is obtained by reacting (a) a compound having at least two isocyanate groups with (b) a polyether polyol, wherein the polyether polyol (b) is a mixture of components comprising at least a polyether polyol (b1) and a polyether polyol (b2). The present invention also relates to the use of the composite element and related methods.

Description

[0001] The invention provides a composite element based on two metal layers joined by polyurethane for use in load-bearing constructions, as well as the production and use of the composite element.

[0002] To construct ships (such as hulls and loading hatches), bridges or high-rise buildings, it is necessary to use construction components that can withstand considerable stresses caused by external forces.

[0003] Composite elements of this type are described, for example, in EP 0 938 410, EP 1 089 875, EP 1 094 938, EP 1 093410, US Pat. No. 6,790,537, EP 1 240 010 and EP 1 315 761.

[0004] A challenge in producing composite components is achieving good, uniform, and bubble-free filling of the air space between the two steel sheets. Furthermore, the sheet surfaces must be thoroughly moistened, and sufficiently good adhesion must be established between the sheet and the polyurethane layer. Many polyurethanes have different expansion properties than the sheets used, and therefore, the polyurethane may separate from the sheets under temperature fluctuations. Furthermore, the reaction product used to produce the polyurethane must be selected so that it does not shrink significantly during the curing process, causing it to separate from the sheets. Furthermore, the structural components of the present invention must withstand high mechanical and dynamic stresses.

[0005] These problems can surprisingly be solved by a composite element as described below, which has the following layer structure:

[0006] (i) Metals from 2 mm to 20 mm,

[0007] (ii) a dense polyurethane formulation of 10 mm to 100 mm, obtained by reacting

[0008] (a) a compound having at least two isocyanate groups,

[0009] (b) polyether polyols,

[0010] Optionally in the presence of

[0011] (c) catalyst and / or

[0012] (d) auxiliaries and / or additives,

[0013] (e) a chain extender,

[0014] (iii) Metals from 2 mm to 20 mm,

[0015] wherein the compound a) having at least two isocyanate groups has an NCO content of 20%

[0016] to 50%, and the polyether polyol (b) is a mixture of components comprising at least the polyether polyol (b1) and the polyether polyol (b2),

[0017] The number average molecular weight of polyether polyol (b1) is 3.0x10 3 g / mol to 7.0x10 3 g / mol, with an average functionality of 2.2 to 2.7,

[0018] The number average molecular weight of polyether polyol (b2) is 0.15x10 3 g / mol to 2.0x10 3 g / mol, with an average functionality of 2.5 to 3.5,

[0019] wherein the polyether polyol (b1) is present in the mixture in an amount of 50% to 95% by weight,

[0020] The polyether polyol (b2) is present in the mixture in an amount of 5 to 50% by weight.

[0021] The present invention therefore provides a composite element having the following layer structure:

[0022] (i) Metals from 2 mm to 20 mm,

[0023] (ii) a dense polyurethane formulation of 10 mm to 100 mm, the polyurethane being obtainable by reacting

[0024] (a) a compound having at least two isocyanate groups,

[0025] (b) polyether polyols,

[0026] Optionally in the presence of

[0027] (c) a catalyst and / or

[0028] (d) auxiliaries and / or additives,

[0029] (e) Chain extender

[0030] (iii) Metals from 2 mm to 20 mm,

[0031] The polyether polyol (b) is a mixture of at least polyether polyol (b1) and polyether polyol (b2). The polyether polyol (b1) and polyether polyol (b2) are preferably different.

[0032] The metal is preferably selected from aluminum, iron, copper, brass, and steel. The metal is preferably steel. The steel may be standard steel, hardened steel, chrome-vanadium steel, weathering steel, or upgraded stainless steel. Vanadium steel is preferred for lightweight bridge construction. Stainless steel is used in applications where corrosion is significant.

[0033] Copper and brass and their alloys (eg bronze) are preferably used for the construction of buildings. Hardened aluminum is used for reducing the weight of armored vehicles and corresponding switch boxes, especially in the military field.

[0034] Alternatively, other layer materials can also be used, for example sheets of wood, wood fiber composites or plastic.

[0035] The selection of suitable materials depends on requirements such as strength, rigidity, corrosion resistance, resistance to chemicals, fatigue resistance, ductility, fracture resistance, behavior at high or low temperatures, as well as aesthetic appearance, desired coatings, impact resistance and weldability.

[0036] The polyurethanes described hereinafter are suitable for bonding to all materials, but very particularly bring positive properties to metals, in particular steel or stainless steel as outer layer material. In a preferred embodiment, the composite element is a plate.

[0037] In the context of the present invention, compact polyurethane refers to a polyurethane that has been prepared without the addition of a blowing agent. However, it is possible that the polyol used contains traces of residual water. The residual water content is preferably less than 0.5 wt %, more preferably 0 wt % to 0.1 wt %, and more preferably 0 wt % to 0.03 wt %, based on the gross weight of the reaction mixture. The density of the compact polyurethane is more preferably greater than 900 g / L, more preferably greater than 950 g / L, and especially greater than 1000 g / L.

[0038] Preferably, the polyether polyol (b1) is present in the mixture in an amount of 50 to 95% by weight, more preferably 55 to 90% by weight, and particularly preferably 60 to 85% by weight. At the same time, the average functionality of the polyether polyol (b1) is preferably 1.7 to 2.9, more preferably 1.95 to 2.8, more preferably 2.2 to 2.7, and particularly preferably 2.4 to 2.6.

[0039] In another preferred embodiment, polyether polyol (b1) has a 3 g / mol and 7.0x10 3 g / mol, preferably 4.0x10 3 g / mol and 6.0x10 3 The number average molecular weight is between g / mol.

[0040] The polyether polyol (b2) is preferably present in the mixture in an amount of 5% to 50% by weight. At the same time, in another preferred embodiment, the average functionality of the polyether polyol (b2) is 1.9 to 5.9, preferably 2.0 to 4.8, more preferably 2 to 4, even more preferably 2.5 to 3.5, and especially preferably 2.9 to 3.1.

[0041] In addition, in a preferred embodiment, the number average molecular weight of the polyether polyol (b2) is 0.15x10 3 g / mol and 4.0x10 3 g / mol, preferably between 0.15x10 3 g / mol and 2.0x10 3 g / mol, more preferably 0.15x10 3 g / mol and 1.0x10 3 g / mol, and particularly preferably between 0.15x10 3 g / mol and 0.6x10 3 Between g / mol.

[0042] The weight values ​​listed for polyether polyols (b1) and (b2) are based on the total weight of the mixture of polyether polyols (b1) and (b2) and, in a preferred embodiment, add up to 100% by weight. In another preferred embodiment, at least one further polyol may be present.

[0043] Preferably, the difference in number average molecular weight between polyether polyols (b1) and (b2) is at least 0.5×10 3 g / mol, more preferably at least 1.0x10 3 g / mol, even more preferably at least 2.0x10 3 g / mol, and particularly preferably at least 3.5x10 3 g / mol.

[0044] In a preferred embodiment, a chain extender is present in the composite element. The chain extender used is preferably a substance having a molecular weight of less than 150 g / mol, more preferably 60 g / mol to 146 g / mol, wherein the chain extender has at least two hydrogen atoms reactive toward isocyanates. They can be used individually or in mixtures. Preferred examples are aliphatic, cycloaliphatic, and / or araliphatic diols having 2 to 8 carbon atoms, preferably ethylene glycol, propane-1,3-diol, 1,2-dihydroxycyclohexane, 1,3-dihydroxycyclohexane, 1,4-dihydroxycyclohexane, diethylene glycol, dipropylene glycol, butane-1,4-diol, and hexane-1,6-diol. Another preferred embodiment is a mixture of diols having 2 to 8 carbon atoms, preferably 4 to 6 carbon atoms. The chain extender more preferably comprises dipropylene glycol and butanediol.

[0045] If chain extenders, crosslinkers or mixtures thereof are used for the preparation of polyisocyanate polyaddition products, they are preferably used in amounts of 0% to 30% by weight, preferably 2% to 20% by weight, based on the total weight of the isocyanate-reactive (b) polyether polyols used.

[0046] Useful compounds comprising isocyanates include well-known aliphatic, cycloaliphatic, araliphatic and / or aromatic isocyanates, preferably diisocyanates. Also di- and / or polyisocyanates comprising ester, urea, allophanate, carbodiimide, uretdione and / or carbamate groups can be used.

[0047] In a preferred embodiment, the compound having an isocyanate group comprises the isocyanate diphenylmethane 2,4′-, 2,2′- and / or 4,4′-diisocyanate (MDI) and / or polyphenylpolymethylene polyisocyanate (PMDI), more preferably polyphenylpolymethylene polyisocyanate (PMDI).

[0048] The polyurethane formulations in the described composite elements have a hardness of greater than 45 Shore D, preferably greater than 55 Shore D, more preferably greater than 60 Shore D, measured at room temperature according to DIN 53505, and at the same time a hardness of greater than 35 Shore D, preferably greater than 40 Shore D and most preferably greater than 45 Shore D at 100°C.

[0049] In another preferred embodiment, the polyurethane composition has an elastic modulus of greater than 275 MPa in the range of -45°C to +50°C according to DIN 53504.

[0050] The adhesion between the polyurethane composition and the metal part is preferably greater than 1 MPa, more preferably greater than 2 MPa and even more preferably greater than 4 MPa.

[0051] The elongation at break of the polyurethane composition in the temperature range of -45°C to +50°C according to DIN 53504 is preferably greater than 10%, more preferably greater than 20% and particularly preferably greater than 30%.

[0052] The tensile strength of the polyurethane composition according to DIN 53504 is preferably greater than 10 MPa, more preferably greater than 15 MPa and even more preferably greater than 20 MPa.

[0053] The compressive strength of the polyurethane composition is preferably greater than 8 MPa, more preferably greater than 15 mPa and even more preferably greater than 20 MPa.

[0054] More preferably, the polyurethane composition has at least two, more preferably 3, more preferably 4, even more preferably 5 of the mechanical properties detailed above, and in a particular embodiment, all 6 properties mentioned within the preferred ranges described in each case.

[0055] In addition to the polyether polyols according to the invention, aliphatic, araliphatic, cycloaliphatic and / or aromatic carboxylic acids can also be used to optimize the progression of hardness when preparing polyurethane compositions. Preferred carboxylic acids of this type are formic acid, acetic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, adipic acid, citric acid, benzoic acid, salicylic acid, phenylacetic acid, phthalic acid, ricinoleic acid, toluenesulfonic acid, derivatives of the aforementioned acids, isomers of the aforementioned acids, and any desired mixtures of the aforementioned acids. The proportion by weight of these acids is preferably 0% to 5% by weight, preferably 0.2% to 2% by weight, based on the total weight of the components used to prepare the polyurethane composition.

[0056] The catalysts (c) used may be compounds generally known for accelerating the reaction of isocyanates with isocyanate-reactive compounds, preferably used in a total content of 0.001 to 15% by weight, in particular 0.05 to 6% by weight, based on the weight of the total isocyanate-reactive compounds used. The following compounds are preferably used: triethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N,N,N',N'-tetramethyldiaminodiethyl ether, bis(dimethylaminopropyl)urea, N-methyl- or N-ethylmorpholine, N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylbutanediamine, N,N,N',N'-tetramethylhexane-1,6-diamine, pentamethyldiethylenetriamine, dimethylpiperazine, N-dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-azabicyclo[2.2.0]octane, 1,4-diazabicyclo[2.2.2]octane (Dabco) and alkanolamine compounds such as triethanolamine, triisopropanolamine, N- Methyl- and N-ethyl-diethanolamine, dimethylaminoethanol, 2-(N,N-dimethylaminoethoxy)ethanol, N,N′,N″-tris-(dialkylaminoalkyl)hexahydrotriazines, for example N,N′,N″-tris(dimethylaminopropyl)-s-hexahydrotriazine, iron(II) chloride, zinc chloride, lead octoate and preferably tin salts, such as tin dioctoate, tin diethylhexanoate, dibutyltin dilaurate and / or di(dodecylthio)dibutyltin, 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali metal hydroxides, such as sodium hydroxide, alkali metal alkoxides, such as sodium methoxide and potassium isopropoxide, and / or alkali metal salts of long-chain fatty acids having 10 to 20 carbon atoms and optionally lateral OH groups.

[0057] It is advantageous to carry out the preparation of the polyurethane composition in the presence of a catalyst (c), since this accelerates and improves curing and adhesion.

[0058] Optionally, further fillers, auxiliaries and / or additives can be added to the mixture of components for preparing the polyurethane formulation based on the polyisocyanate polyaddition product. Examples include fillers, surfactants, dyes, pigments, flame retardants, hydrolysis stabilizers, fungistatic and bacteriostatic substances.

[0059] Useful surfactants include, for example, compounds that aid in homogenizing the starting materials and are also suitable for adjusting the cell structure of the polyurethane formulation. Preferred examples include emulsifiers (such as castor oil sulfate or sodium salts of fatty acids), salts of fatty acids with amines (such as diethylammonium oleate, diethanolammonium stearate, diethanolammonium ricinoleate), and sulfonates (such as alkali metal or ammonium salts of dodecylbenzene- or dinaphthylmethanedisulfonic acid and ricinoleic acid). The surfactant is preferably used in an amount of 0.01 to 5% by weight, based on 100% by weight of the total amount of isocyanate-reactive compounds (b) used.

[0060] Examples of preferred flame retardants include tricresyl phosphate, tris(2-chloroethyl)phosphate, tris(2-chloropropyl)phosphate, tris(1,3-dichloropropyl)phosphate, tris(2,3-dibromopropyl)phosphate, tetrakis(2-chloroethyl)ethylene diphosphate, dimethylmethanephosphonate, diethyldiethanolamine methylphosphonate, and commercial halogen-containing flame-retardant polyols. In addition to the halogen-substituted phosphates already mentioned, inorganic or organic flame retardants such as red phosphorus, aluminum oxide hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate, expandable graphite, or cyanuric acid derivatives such as melamine, or mixtures of at least two flame retardants such as ammonium polyphosphate and melamine and optionally corn starch, or ammonium polyphosphate, melamine and expandable graphite and / or optionally aromatic polyesters can also be used to impart flame retardancy to the polyisocyanate polyaddition products. In general, it has been found suitable to use from 5% to 50% by weight, preferably from 5% to 25% by weight, of the flame retardants mentioned, based on the weight of the total isocyanate-reactive compounds used.

[0061] Fillers, especially reinforcing fillers, are conventional organic and inorganic fillers, reinforcing agents, weighting agents, agents for improving wear characteristics, coating agents, etc. Preferred examples of fillers are inorganic fillers such as silica minerals, for example sheet silicates such as antigorite, serpentine, hornblende, amphibole, chrysotile and talc, metal oxides such as kaolin, aluminum oxide, titanium oxide and iron oxide, metal salts such as chalk, barite, and inorganic pigments such as cadmium sulfide and zinc sulfide, as well as glass, etc. Kaolin (china clay), aluminum silicate and coprecipitates of barium sulfate and aluminum silicate are preferably used, as well as natural and synthetic fibrous minerals such as wollastonite, short metal and glass fibers. Preferred organic fillers are, for example, carbon, melamine, rosin, cyclopentadiene-based resins and graft polymers, as well as cellulose fibers, polyamide-polyacrylonitrile fibers, polyurethane fibers, polyester fibers based on aromatic and / or aliphatic dicarboxylic acid esters, especially carbon fibers. Inorganic and organic fillers can be used alone or as a mixture.

[0062] When preparing the polyurethane composition, preferably 10% to 70% by weight of filler is used, based on the weight of the total polyurethane composition. The fillers used are preferably talc, kaolin, calcium carbonate, barite, glass fibers and / or glass microspheres. The particle size of the filler is preferably selected so that the components used to prepare the polyurethane composition are introduced into the spaces between the preferably pretreated metal surfaces without obstruction.

[0063] More preferably, the particle size of the filler is less than 0.5 mm.

[0064] The filler is preferably mixed into the polyol component.

[0065] Fillers are preferably used to reduce the thermal expansion coefficient of polyisocyanate polyaddition products, which is greater, for example, compared to steel, and thus to match the expansion coefficient of the polyurethane composition to that of steel. This is particularly advantageous for a durable and stable bond, i.e., between the polyurethane composition and the metal surface, since the stresses that arise between the layers under thermal stress are low.

[0066] The weight of the polyurethane composition is equal to the total weight of all components used to prepare the polyurethane composition.

[0067] To prepare the polyurethane composition, the isocyanate is reacted with the isocyanate-reactive compound in such an amount that the equivalent ratio of the NCO groups of the isocyanate to the sum of the reactive hydrogen atoms of the isocyanate-reactive compound is from 0.85 to 1.25:1, preferably from 0.95 to 1.15:1 and in particular from 1 to 1.05:1. If (ii) at least partially comprises bound isocyanurate groups, a ratio of NCO groups to the sum of reactive hydrogen atoms of from 1.5 to 60:1, preferably from 1.5 to 8:1, is generally used.

[0068] The polyisocyanate polyaddition products are generally prepared by the one-shot process or the prepolymer process, for example by means of high-pressure or low-pressure technology.

[0069] It has been found to be particularly advantageous to work by a two-component process and to combine the isocyanate-reactive compound (b), the optional catalyst (c) and / or auxiliaries and / or additives and fillers (d) in component (A) and preferably mix them intimately, and to use an isocyanate as component (B).

[0070] The starting components are generally mixed at a temperature of 0° C. to 100° C., preferably 20° C. to 60° C., and introduced into the spaces between the preferably pretreated metal surfaces as already described. Mixing can be carried out mechanically by means of a stirrer or stirrer screw, or in the case of high-pressure treatment by a countercurrent mixing operation. The reaction temperature, i.e. the temperature at which the conversion is achieved, is generally above 20° C., preferably 50° C. to 150° C. This is preferably achieved by heating the metal surface before and / or during the introduction of the materials. Suitable methods for heating the metal surface are known to those skilled in the art. Examples include flame treatment or inductive methods.

[0071] The present invention further provides a method for producing the aforementioned composite element, wherein

[0072] (a) a compound containing at least two isocyanate groups is mixed with

[0073] (b) a polyether polyol, wherein the polyether polyol (b) is a mixture of components comprising at least a polyether polyol (b1) and a polyether polyol (b2),

[0074] Optionally in the presence of

[0075] (c) a catalyst, and / or

[0076] (d) auxiliaries and / or additives, and / or

[0077] (e) a chain extender, and allowing the mixture to cure in contact with the metal layer, thereby resulting in a permanent bond between the metal surface and the polyurethane, which is important for the composite.

[0078] Any mixture comprising components (a), (b), optionally (c), (d) and (e) for preparing the polyurethane composition is also referred to as reaction mixture.

[0079] The water content of the reaction mixture comprising components (a), (b) and optionally (c), (d), and / or (e) is preferably between 0% and 0.03% by weight, based on the weight of the reaction mixture. The water content, in particular the water content of the polyether polyol (b), can be adjusted, for example by distillation, so that the aforementioned values ​​are achieved in the reaction mixture. Water leads to the formation of gases and thus bubbles, which should be avoided in preferred embodiments.

[0080] Therefore, in another preferred embodiment, a substance that binds water and thus prevents the foaming reaction is added to the reaction mixture. Examples of preferred such substances are molecular sieves. Preferred molecular sieves are silicates and oxazolidines, which are preferably used in finely dispersed form. The preferred addition amount of these substances is 0.05% by weight to 5% by weight, based on the weight of the reaction mixture, preferably based on component (b).

[0081] In a preferred embodiment, the NCO content of the isocyanate group-containing compound (a) is 20% to 50%, preferably 20% to 40%, and more preferably 20% to 35%, and especially preferably 20% to 32%.

[0082] In another preferred embodiment of the described process, the mixture of polyether polyols (b1) and (b2), optionally comprising (c) catalysts, (d) auxiliaries and / or additives and / or chain extenders (e), has a viscosity measured at 23° C. according to DIN 53019 of less than 6.0 x 10 3 mPas, preferably less than 5.0x10 3 mPas, and more preferably less than 4.0x10 3 mPas.

[0083] In a preferred embodiment of the method, the compound (a) containing an isocyanate group is a diisocyanate and one or more isocyanates having a molecular weight of 0.076x10 3 g / mol to 2x10 3 g / mol of polyols (preferably polyether polyols). In another preferred embodiment, the compound containing isocyanate groups is polyphenyl polymethylene polyisocyanate (PMDI). Preferably, the polyphenyl polymethylene polyisocyanate has a viscosity of between 60 mPas and 2500 mPas, preferably between 80 mPas and 750 mPas, and most preferably a viscosity of between 100 mPas and 350 mPas, measured at 23 ° C according to DIN 53019.

[0084] To achieve a good bond, it is advantageous to pretreat the metal surface before contact with the polyurethane formulation. This pretreatment is preferably performed immediately before the components of the polyurethane composition are introduced. Preferably, the metal surface that comes into contact with the polyurethane formulation and adheres to the polyurethane formulation after the composite element is prepared is sandblasted with sand. This sandblasting is performed by conventional methods, preferably under high pressure.

[0085] While cleaning the surface, it is roughened by sandblasting. Each of these causes better adhesion of the polyurethane formulation on the metal surface. Sandblasting is preferably carried out before the components for preparing the polyurethane are introduced. In addition, adhesion promoters can also be applied to these surfaces, which further improve the bonding between the polyurethane composition and the metal.

[0086] The preferably pretreated metal surfaces of the composite element are fixed in a suitable configuration, preferably parallel to each other. The distance is selected so that the space between the metal surfaces has a thickness of 10 mm to 100 mm. The metal parts are preferably fixed with spacers. The obvious edges of the intermediate space between the metals are preferably sealed so that the space between the preferably pretreated metal surfaces can be filled with the reaction product of the polyurethane composition and prevent these components from flowing out. The sealing is preferably achieved using a polymer film or metal foil and / or plastic or metal sheet, which in a preferred embodiment can also serve as spacers. Particularly suitable filling methods are described in EP 1 755 886.

[0087] Depending on the geometry, it is preferred that the spaces between the treated metal surfaces are filled so that air bubbles are prevented which would otherwise deteriorate the bond between the metal and the polyurethane composition and form corrosion nuclei.

[0088] The filling of the spaces between the preferably pretreated metal surfaces can be carried out with conventional conveying means, such as high-pressure or low-pressure machines, preferably high-pressure machines. The components of the polyurethane composition are preferably fed continuously.

[0089] The delivery output can be varied depending on the volume to be filled. In order to ensure homogeneous complete curing of the polyurethane composition, the delivery output and the delivery unit for the polyurethane composition are selected such that the space to be filled between the metal surfaces is filled within 5 to 20 minutes.

[0090] In another preferred method, an adhesion promoter is applied to the metal surface, preferably after sandblasting. The adhesion promoter is preferably selected from polyurethanes, polyureas, polyisocyanurates, epoxides, or silanes. Polyurethane-based adhesion promoters are particularly preferred because these adhesion promoters form particularly good bonds to metal surfaces.

[0091] The invention further provides a composite element obtainable by one of the above-described methods.

[0092] The present invention further provides for the use of the composite elements described herein in vehicles, ships (especially deck structures and hulls), aircraft, or building structures (preferably bridges or buildings). In a preferred embodiment, the composite elements are used as floor coverings, especially in high-rise buildings. In another preferred embodiment, the composite elements provide protection against high-speed flying objects.

[0093] The invention further provides vehicles, ships, aircraft or building structures, in particular bridges and high-rise buildings, comprising the composite elements described herein, and particularly preferred are floors of high-rise buildings.

[0094] The composite element of the invention should not be confused with conventional sandwich elements which contain rigid polyurethane and / or polyisocyanurate foam as a core and are usually used for thermal insulation. Such known sandwich elements are not suitable for the mentioned fields of application due to their relatively low mechanical durability. Example:

[0095] Feed:

[0096] Polyol 1: Polyether alcohol prepared by alkoxylation of propylene glycol with propylene oxide and ethylene oxide, having a functionality of 1.76, a molecular weight of 3350 g / mol and an OH number of 29.5 mg KOH / g

[0097] Polyol 2: A polyether alcohol prepared by alkoxylation of sucrose and glycerol with propylene oxide and ethylene oxide, having a functionality of 4.15, a molecular weight of 5250 g / mol, and an OH number of 44 mg KOH / g

[0098] Polyol 3: Polyether alcohol prepared by alkoxylation of ethylenediamine with propylene oxide, having a functionality of 4, a molecular weight of 300 g / mol and an OH number of 750 mg KOH / g

[0099] Polyol 4: A polyether alcohol prepared by alkoxylation of glycerol with propylene oxide and ethylene oxide, having a functionality of 2.49, a molecular weight of 5170 g / mol, and an OH number of 27 mg KOH / g

[0100] Polyol 5: Polyether alcohol prepared by alkoxylation of toluenediamine with propylene oxide, having a functionality of 3.9, a molecular weight of 550 g / mol and an OH number of 398 mg KOH / g

[0101] Polyol 6: Polyether alcohol prepared by alkoxylation of trimethylolpropane with propylene oxide, having a functionality of 3.0, a molecular weight of 200 g / mol and an OH number of 860 mg KOH / g

[0102] KV 1: Dipropylene glycol

[0103] KV 2: Butane-1,4-diol

[0104] Zeo: Zeolite paste, 50% in castor oil

[0105] DF:AF 9000 defoamer / antifoaming agent

[0106] ISO 1: Lupranat MP 102 from BASF Polyurethanes GmbH (prepolymer based on 4,4′MDI prepolymer and polyether polyol, having an NCO content of 23% and a viscosity of 650 mPas at 25° C.)

[0107] ISO2: Lupranat M20S from BASF Polyurethanes GmbH (polymeric MDI having an NCO content of 31.5% and a viscosity of 210 mPas at 25° C.)

[0108] ISO 3: Lupranat MP 105 from BASF Polyurethanes GmbH (prepolymer based on 4,4′-MDI, PMDI and polyether polyols, having an NCO content of 28.5% and a viscosity of 120 mPas at 25° C.)

[0109] ISO 4: ISO 136 / 26 from BASF Polyurethanes GmbH (a prepolymer based on 4,4′ MDI and polyether polyols having an NCO content of 18% and a viscosity of 1200 mPas at 25° C.)

[0110] ISO 5: ISO 137 / 28 from BASF Polyurethanes GmbH (prepolymer based on 4,4′MDI and polyether polyol, having an NCO content of 18% and a viscosity of 750 mPas at 25° C.)

[0111] ISO 6: ISO 136 / 94 (prepolymer based on 4,4′MDI and polyether alcohol) from BASF Polyurethanes GmbH, having an NCO content of 5.8% and a viscosity of 5500 mPas at 50° C.

[0112] ISO7: a mixture of 48.5% ISO4 and 51.5% ISO5

[0113] To prepare the polyol mixture, the components of the polyol component (polyol, additives, etc.) are first mixed. Subsequently, the polyol component is reacted with the specified isocyanate in the mixing ratios specified in the table. This mixing ratio is selected so that the equivalent ratio of NCO groups in the isocyanate to the sum of reactive hydrogen atoms in the isocyanate-reactive compound is 1.09:1. To determine the hardness or storage modulus, test specimens with a thickness of 1 cm or test sheets with a thickness of 2 mm are prepared. This preparation is carried out as follows:

[0114] The temperature of the polyol mixture and the isocyanate component was room temperature (25°C). The only exception was the isocyanate component ISO 136 / 94. It was processed at a temperature of 50°C. To prepare the test specimens, the appropriate amount of polyol component was initially charged and the appropriate amount of isocyanate component was added. The mixture was then mixed using a Speedmixer from Hauschild. TM The reactive mixture was mixed at 800 rpm for 5 seconds and then at 1800 rpm for 55 seconds. The homogeneously mixed reaction mixture was then introduced into a mold preheated to 100° C. After 1 hour at 100° C., the test specimens were demoulded.

[0115] The hardness of the material is determined based on a 1 cm thick sheet. To this end, the sheet is first conditioned at room temperature for 7 days. The hardness is measured similarly to DIN 53505. To determine the hardness at 50°C and 100°C, the material is stored in an oven at the appropriate temperature for 3 hours. The hardness is then measured directly in the oven at the appropriate temperature to prevent the material from cooling.

[0116] The examples that follow Table 1 are intended to illustrate the effects of the compositions of the present invention.

[0117] Table 1

[0118]

[0119] nd = not determined due to too low Shore hardness of the material at room temperature (RT) As is evident from comparative examples V1 to V4,

[0120] As is clear from Example B1, polyurethanes with the desired properties and an elastic modulus of >275 MPa are obtained in the temperature range of -45°C to +50°C. The polyurethanes obtained in Examples V1 to V4 have a low hardness at 50°C and, therefore, a low elastic modulus of well below 275 MPa. The specific combination of an isocyanate (a) with an NCO content of >20% by weight and a suitable polyol mixture (b) yields suitable polyurethanes. This is illustrated in Examples B2 to B4 relative to Comparative Examples V5 and V6.

[0121]

Claims

1. A composite element having the following layer structure: (i) Metals from 2 mm to 20 mm, (ii) a dense polyurethane formulation of 10 mm to 100 mm, obtained by reacting (a) a compound having at least two isocyanate groups, (b) polyether polyols, Optionally in the presence of (c) catalyst and / or (d) auxiliaries and / or additives, (e) a chain extender, (iii) Metals from 2 mm to 20 mm, wherein the compound a) having at least two isocyanate groups has an NCO content of 20% to 50%, and the polyether polyol (b) is a mixture of components comprising at least a polyether polyol (b1) and a polyether polyol (b2), The number average molecular weight of the polyether polyol (b1) is 3.0 x 10 3 g / mol to 7.0 x 10 3 g / mol, with an average functionality of 2.2 to 2.7, The number average molecular weight of polyether polyol (b2) is 0.15x 10 3 g / mol to 2.0 x 10 3 g / mol, with an average functionality of 2.5 to 3.5, wherein the polyether polyol (b1) is present in the mixture in an amount of 50% to 95% by weight, The polyether polyol (b2) is present in the mixture in an amount of 5 to 50% by weight. 2 . The composite element according to claim 1 , wherein the polyether polyol (b1) has an average functionality of 2.4 to 2.

6. 3 . The composite element according to claim 1 , wherein the polyether polyol (b2) has an average functionality of 2.9 to 3.

1. 4 . The composite element according to claim 1 , wherein the weight of the polyether polyols (b1) and (b2) is based on the total weight of the mixture of the polyether polyols (b1) and (b2).

5. The composite element according to claim 1, wherein the difference in number average molecular weights of the polyether polyols (b1) and (b2) is at least 0.5 x 10 3 g / mol.

6. The composite element according to claim 5, wherein the difference in number average molecular weights of the polyether polyols (b1) and (b2) is at least 1.0 x 10 3 g / mol.

7. The composite element according to claim 5, wherein the difference in number average molecular weights of the polyether polyols (b1) and (b2) is at least 2.0 x 10 3 g / mol.

8. The composite element according to claim 1, wherein a chain extender is present. 9 . The composite element according to claim 8 , wherein the chain extender comprises a mixture of diols having 2 to 8 carbon atoms. 10 . The composite element according to claim 1 , wherein the compound a) having at least two isocyanate groups comprises the isocyanate diphenylmethane 2,4′-, 2,2′- and / or 4,4′-diisocyanate (MDI) and / or polyphenylpolymethylene polyisocyanate. 11 . The composite element according to claim 1 , wherein the polyurethane has a hardness of greater than 45 Shore D, measured according to DIN 53505.

12. A method for producing a composite element according to claim 1, comprising mixing: (a) a compound containing at least two isocyanate groups, (b) a polyether polyol, wherein the polyether polyol (b) is a mixture of components comprising at least a polyether polyol (b1) and a polyether polyol (b2), Optionally in the presence of (c) catalyst and / or (d) auxiliaries and / or additives and / or (e) a chain extender, and curing the mixture by contacting it with the metal layer.

13. The process according to claim 12, wherein the compound a) having at least two isocyanate groups has an NCO content of 20% to 40%.

14. The process according to claim 12, wherein the mixture optionally comprising (c) a catalyst, (d) an auxiliary agent and / or an additive and / or a chain extender (e) has a viscosity measured at 23°C according to DIN 53019-1 of less than 6.0 x 10 3 mPas.

15. The process according to claim 14, wherein the compound a) having at least two isocyanate groups is a diisocyanate and has a molecular weight of 0.076 to 2 x 10 3 g / mol of addition products of polyols.

16. Composite element obtainable by the method according to any one of claims 12 to 15.

17. Use of a composite element according to any one of claims 1 to 11 or 16 in a vehicle, a watercraft, an aircraft or a building structure.

18. Vehicle, watercraft, aircraft or building structure comprising a composite element according to any one of claims 1 to 11 or 16.

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