Composite element made of thermoplastic and polyurethane, method for its production and use

Abstract

The invention relates to a composite element comprising a thermoplastic and a polyurethane adhesively bonded thereto, a process for its production and its use.

Description

[0001] The invention relates to a composite element comprising a thermoplastic and a polyurethane adhesively bonded thereto, a method for its production and its use.

[0002] Polyisocyanate polyaddition products obtainable by reaction of polyisocyanates with isocyanate-reactive compounds and composite components of these products with other plastics are common knowledge. Subjecting these composite components to mechanical loads often leads to undesirable detachment of the plastic from the polyisocyanate polyaddition products. Particularly when composite components are used in automobile construction and such loads cannot be excluded, detachment of the polyisocyanate polyaddition products from other plastics and thus destruction of the composite components is unacceptable.

[0003] Furthermore, efforts are being made, in particular in the automotive industry, to use components that are as light as possible in order to conserve resources both in the production and operation of the vehicle and thus to be able to achieve environmental and economic advantages.

[0004] WO 2010 / 072572 discloses composite elements made of plastics to which polyisocyanate polyaddition products (PUR) are attached in an adhesive manner, wherein the PUR formulation contains a polyester polyol serving as an adhesion promoter. The polyester polyol can be prepared by polycondensation of an acid component and one or more diols, wherein the acid component consists of 83 to 97 mol % of adipic acid and 3 to 17 mol % of phthalic acid, isophthalic acid and / or terephthalic acid. Only general statements are made about other isocyanate-reactive components that are not necessarily required for the production of the polyurethane, without discussing specific features.

[0005] DE 10022280 A1 and DE 10022276 A1 disclose the use of isocyanate prepolymers obtainable by reaction of isocyanates with polyester polyols which must have a functionality of 2 to 3 and an OH number of 40 to 400 mg KOH / g for the production of polyurethanes, wherein adipic acid and / or phthalic anhydride and diols and / or triols are used as starting components. Only general statements are made about the isocyanate-reactive components required for the production of polyurethanes, without discussing specific features.

[0006] DE 19928608 A1 discloses composite elements made of plastics to which polyisocyanate polyaddition products (PUR) are adhesively bonded, wherein the PUR formulation contains polyester polyols with a functionality of 2 to 3. The polyester polyols are based on polycondensation products of adipic acid and / or phthalic anhydride and polytetrahydrofuran (PTHF), 1,6-hexanediol, 1,4-butanediol, monoethylene glycol, diethylene glycol (DEG), trimethylolpropane (TMP) and / or neopentyl glycol. Only general statements are made about the other isocyanate-reactive components, without discussing specific features.

[0007] WO 2013 / 017510 A1 discloses composite elements made of plastics to which polyisocyanate polyaddition products (PUR) are adhesively bonded, wherein the PUR formulation comprises polyester polyols having an ester group concentration of 9 to 10 mol / kg ester and polyether polyols having a molecular weight of less than 5000 g / mol.

[0008] WO 2015 / 185448 A1 discloses a composite element made of at least one covering layer and a polyurethane foam and a method for producing the same, wherein the polyether polyols used have a low molecular weight and the polyester polyols are not produced on the basis of 1,2-propylene glycol.

[0009] It was therefore an object of the present invention to provide composite elements which, owing to their excellent mechanical properties, can be used, for example, in automobile construction and in which the adhesion between the plastic and the polyisocyanate polyaddition product adhering thereto is not lost even under mechanical load.

[0010] It has surprisingly been found that the abovementioned objects can be achieved by the composite element according to the invention.

[0011] The subject of the invention is a composite element comprising

[0012] A. Thermoplastic, B is connected to A by adhesion

[0013] B. The reaction product of a reaction mixture comprising:

[0014] i. an isocyanate component comprising one or more polyisocyanates,

[0015] ii. an isocyanate-reactive component comprising

[0016] ii.1) a first polyether polyol having a molecular weight of at least 6000 g / mol, obtainable by reaction of a starter molecule or a mixture of starter molecules having an OH functionality of 1.8 to 3.5 with ethylene oxide and propylene oxide, wherein the proportion of ethylene oxide in the first polyether polyol is 10-28% by weight, based on the total amount of ethylene oxide and propylene oxide,

[0017] ii.2) one or more polyester polyols having a functionality of greater than 2 and a hydroxyl number of 60-150 mg KOH / g, based on the condensation of adipic acid with 1,2-propylene glycol and at least one other compound having at least two hydroxyl groups,

[0018] ii.3) 1,4-butanediol,

[0019] ii.4) diethyltoluenediamine,

[0020] ii.5) optionally, other polyether polyols,

[0021] ii.6) optionally, a chain extender and / or a crosslinker,

[0022] ii.7) optionally, a catalyst,

[0023] ii.8) optionally, a blowing agent,

[0024] ii.9) Optionally, auxiliaries and / or additives.

[0025] The composite element according to the invention therefore comprises at least one thermoplastic and a reaction product adhering to the plastic, which reaction product is obtainable from the reaction of a reaction mixture comprising an isocyanate component comprising one or more polyisocyanates and an isocyanate-reactive component, which comprises at least four components, namely, in addition to 1,4-butanediol and diethyltoluenediamine, a first polyether polyol having a molecular weight of at least 6000 g / mol, obtainable from the reaction of a starter molecule or a mixture of starter molecules having an OH functionality of 1.8 to 3.5 with ethylene oxide and propylene oxide, the proportion of ethylene oxide being 10-28% by weight, based on the total amount of ethylene oxide and propylene oxide, and one or more polyester polyols having a functionality of more than 2 and a hydroxyl number of 60-150 mg KOH / g, based on the condensation of adipic acid with 1,2-propylene glycol and at least one further compound having at least two hydroxyl groups. Furthermore, the reaction mixture may comprise, for example, further polyether polyols, chain extenders and / or crosslinkers, catalysts, blowing agents or auxiliaries and / or additives.

[0026] Preferably, the isocyanate-reactive component ii. comprises 50-90% by weight of the first polyether polyol ii.1), based on the total amount of the isocyanate-reactive component ii.

[0027] Further preferably, the isocyanate-reactive component ii. comprises 0.1-10% by weight of one or more polyester polyols ii.2), optionally with a proportion of 50-90% by weight of the first polyether polyol ii.1), based in each case on the total amount of the isocyanate-reactive component ii.

[0028] Further preferably, the isocyanate-reactive component ii. comprises 0.1-2.0% by weight of butanediol ii.3), optionally with a proportion of 50-90% by weight of the first polyether polyol ii.1) and / or a proportion of 0.1-10% by weight of one or more polyester polyols ii.2), in each case based on the total amount of the isocyanate-reactive component ii.

[0029] Further preferably, the isocyanate-reactive component ii. comprises 0.01–2.0% by weight of diethyltoluenediamine ii.4), optionally with a proportion of 50–90% by weight of the first polyether polyol ii.1), a proportion of 0.1–10% by weight of one or more polyester polyols ii.2) and / or a proportion of 0.1–2% by weight of butanediol ii.3), in each case based on the total amount of the isocyanate-reactive component ii.

[0030] Preference is therefore given to isocyanate-reactive components ii. in which the proportion of ii.1) is 50-90% by weight and / or the proportion of ii.2) is 0.1-10% by weight and / or the proportion of ii.3) is 0.1-2.0% by weight and / or the proportion of ii.4) is 0.01-2.0% by weight, in each case based on the total amount of isocyanate-reactive component ii.

[0031] In one embodiment, the isocyanate-reactive component according to the invention consists of components ii.1), ii.2), ii.3) and ii.4) and optionally ii.5), ii.6), ii.7), ii.8) and / or ii.9).

[0032] In another embodiment, the reaction product of the reaction mixture has a 3 or less or 100 to 155 kg / m 3 , preferably 140kg / m 3 or less or 100 to 140 kg / m 3 , and more preferably 130kg / m 3 or less, especially 100 to 130 kg / m 3 density.

[0033] In a preferred embodiment, the first polyether polyol ii.1) has a molecular weight of 6000-10000 g / mol, more preferably 6000-8000 g / mol, even more preferably 6000-7000 g / mol, most preferably 6000-6500 g / mol, in particular 6100-6300 g / mol.

[0034] In a further embodiment, for the first polyether polyol ii.1), the proportion of ethylene oxide, based on the total amount of ethylene oxide and propylene oxide, is 15-25% by weight, in particular 18-23% by weight, in each case in the first polyether polyol ii.1).

[0035] Further preferred are composite elements in which the starter molecule for the first polyether polyol ii.1) - if a single starter molecule is present - is selected from ethylene glycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol, 4,4'-dihydroxydiphenylpropane, glycerol, trimethylolpropane, erythritol, sorbitol, ammonia, ethylenediamine, aniline, ethanolamine and triethanolamine, or - if a mixture of starter molecules is present - the mixture consists of components selected from the group consisting of the compounds mentioned. Particularly advantageous are composite elements in which the starter molecule for the first polyether polyol ii.1) is glycerol, or the mixture of starter molecules comprises glycerol.

[0036] The isocyanate-reactive component comprises a polyester polyol ii.2 based on the condensation of adipic acid with 1,2-propylene glycol and at least one further compound having at least two hydroxyl groups. In a preferred embodiment, the at least one further compound having at least two hydroxyl groups is selected from ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol and trimethylolpropane and mixtures thereof, particularly preferably a mixture of trimethylolpropane and 1,6-hexanediol.

[0037] The composite element according to the invention may contain one or more conventional thermoplastics as thermoplastic A., for example acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), acrylonitrile-styrene-acrylate (ASA), styrene-acrylonitrile (SAN), polycarbonate (PC), thermoplastic polyurethane (TPU), polyvinyl chloride (PVC), thermoplastic polyolefins (TPO) (optionally post-crosslinked), such as polyethylene and polypropylene, styrene-maleic anhydride copolymers (SMA) and blends, i.e. mixtures, thereof. The composite element preferably contains the thermoplastic PVC, particularly preferably a PVC film, as thermoplastic A.

[0038] The thermoplastics A. used for producing the composite elements can be used in customary form, for example as films, preferably with a layer thickness of 0.2 to 2 mm.

[0039] Such membranes are commercially available and their production is common general knowledge.

[0040] If necessary, the composite element can additionally have a carrier made of a thermosetting or thermoplastic or a self-supporting injection-molded part made of, for example, a fiber-reinforced thermoplastic or thermosetting plastic on the side facing away from the thermoplastic A. In industrial practice, preference is given to using carrier materials made of polyurethane, polycarbonate / acrylonitrile-butadiene-styrene copolymers, polypropylene and acrylonitrile-butadiene-styrene, which may optionally be fiber-reinforced, in particular glass-fiber-reinforced.

[0041] According to the invention, polyisocyanate polyaddition products B., for example polyurethanes which may optionally have isocyanurate structures and / or urea structures, are bonded in an adhesive manner to thermoplastics A. These polyisocyanate polyaddition products B., preferably polyurethanes, which can be present in compact or preferably cellular form, particularly preferably in open-cell form, for example as flexible foams, semirigid foams or rigid foams, particularly preferably as semirigid foams, are prepared by reacting the corresponding components of the reaction mixture according to the invention in the presence of plastic A.

[0042] Particularly preferred are composite elements in which the adhesion between the thermoplastic A. and the reaction product B. of the reaction mixture is at least 26 N / 50 mm, preferably at least 27 N / 50 mm, more preferably at least 29 N / 50 mm, measured according to DIN 53357 A as disclosed in the Examples section.

[0043] Another subject of the present invention is a method for producing a composite element according to the invention. This method comprises the steps I. providing a thermoplastic A., an isocyanate component i. and an isocyanate-reactive component ii.,

[0044] II. mixing the isocyanate component i. and the isocyanate-reactive component ii. provided in step I. to obtain a reaction mixture,

[0045] III. contacting the reaction mixture obtained in step II. with the thermoplastic A. provided in step I. so that the reaction mixture contacts the thermoplastic A.,

[0046] IV. foaming the reaction mixture obtained in step II. while in contact with a thermoplastic to obtain a composite element comprising a thermoplastic A. to which a reaction product B. of the reaction mixture is adhesively connected,

[0047] V. Demolding the composite element obtained in step IV.

[0048] The present invention also provides for the use of the composite elements according to the invention in components in vehicle and aircraft construction and in the building industry, for example in dashboards, door linings, parquet, consoles, armrests, vehicle seats, backrests, headrests, roof linings or rearview mirrors.

[0049] Finally, the invention also provides components in vehicle or aircraft construction or in the construction industry which contain the composite element according to the invention, for example dashboards, door linings, parquet, consoles, armrests, vehicle seats, backrests, headrests, roof linings or rearview mirrors.

[0050] Polyether polyols are generally polyhydroxy polyethers that can be prepared in a manner known per se by addition polymerization of alkylene oxides onto multifunctional starter compounds in the presence of a catalyst. Polyether polyols can be made, for example, from starter compounds or starter compound mixtures having an average of 2 to 6 active hydrogen atoms and one or more alkylene oxides. Conventional starter compounds are molecules having 2 to 8, particularly 3 to 8 or 3 to 6 hydroxyl groups per molecule, such as triethanolamine, glycerol, trimethylolpropane, pentaerythritol, sorbitol and sucrose. These starter compounds can be used alone or in the form of a mixture, especially with difunctional starter compounds such as diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol and 1,6-hexanediol. One or more alkylene oxides, such as ethylene oxide, propylene oxide and butylene oxide, can be used in the production of polyether polyols. They can be used alone or in the form of a mixture. When used in a mixture, the alkylene oxide can be reacted in a random or block manner, or in these two ways successively.

[0051] The first polyether polyol ii.1) according to the invention has a molecular weight of at least 6000 g / mol and is obtainable by reaction of a starter molecule or a mixture of starter molecules having an OH functionality of 1.8 to 3.5 with ethylene oxide and propylene oxide, wherein the proportion of ethylene oxide in the first polyether polyol ii.1) is 10-28% by weight, preferably 15-25% by weight, more preferably 18-23% by weight, based on the total amount of ethylene oxide and propylene oxide. In this case, a mixture of ethylene oxide and propylene oxide can be used in the production of the first polyether polyol ii.1), or the two alkylene oxides can be used successively. Preference is given to using propylene oxide first and then ethylene oxide. In a preferred embodiment, the starter molecule or - if a mixture of starter molecules is used - one of the starter molecules is selected from ethylene glycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol, 4,4'-dihydroxydiphenylpropane, glycerol, trimethylolpropane, erythritol, sorbitol, ammonia, ethylenediamine, aniline, ethanolamine and triethanolamine; in a particularly preferred embodiment, it is glycerol. Particularly preferred is a first polyether polyol ii.1) having a molecular weight of 6000-10000 g / mol or 6000-8000 g / mol, more preferably 6000-7000 g / mol, even more preferably 6000-6500 g / mol, most preferably 6100-6300 g / mol.

[0052] Polyester polyols are usually made by polycondensation of acids with diols and triols in a manner known to those skilled in the art. Instead of or in addition to acids, acid derivatives such as anhydrides and / or acid alkyl esters can certainly also be used. Polycondensation is usually carried out in bulk, i.e. without solvent. It can also be carried out in the presence of a solvent. Catalysts can be used to accelerate the polycondensation. It is also possible to accelerate the reaction by applying reduced pressure. It can also be carried out under atmospheric pressure, wherein preferably an inert gas, such as nitrogen, is used at this time to discharge the resulting reaction water or alkyl alcohol, particularly when the polycondensation is close to the end.

[0053] The polyester polyols ii.2) according to the invention are based on the condensation of adipic acid with 1,2-propylene glycol and at least one further compound having at least two hydroxyl groups and have a functionality of more than 2 and a hydroxyl number of 60-150 mg KOH / g.

[0054] The hydroxyl value of the polyester polyol ii.2) is adjusted by appropriately selecting the molar ratio of the hydroxyl groups from 1,2-propylene glycol and the at least one other compound having at least two hydroxyl groups to the carboxyl groups of adipic acid or carboxyl equivalents when adipic acid derivatives are used. The functionality of the polyester polyol ii.2) is adjusted by the respective ratios of the polyols. For example, when 1,2-propylene glycol and 1,1,1-trimethylolpropane (TMP) are used in a 1 molar batch (after removal of the cleavage product water or optional alkyl alcohol, the batch amount of the polyester polyol corresponds to the number average molar mass), the functionality F of the polyester polyol ii.2) is calculated from the molar amount of TMP used according to the formula: F=2+number of moles of TMP.

[0055] The OH number (OHZ, hydroxyl number) is a measure of the hydroxyl content of an individual polyol or a polyol mixture. The OHZ specifies the amount of potassium hydroxide in milligrams which corresponds to the amount of acetic acid bound to 1 gram of polyol during the acetylation.

[0056] In the present application, functionality is theoretical functionality, based on the number of active hydrogens in the initiator molecule for the production of polyether polyols or polyester polyols. For each single polyol, theoretical functionality is therefore an integer. The mixture of such polyols (e.g., made from a mixture of polyols generated with difunctional or trifunctional initiators) can have a theoretical functionality between the functionality of the initiator. For example, a polyol mixture made from an equimolar mixture of ethylene glycol and glycerol has a theoretical functionality of 2.5.

[0057] The generally known (cyclo)aliphatic and / or in particular aromatic polyisocyanates can be used as polyisocyanates for the isocyanate component i. Particularly suitable for producing the composite elements according to the invention are aromatic diisocyanates, preferably diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI), very particularly preferably MDI. The isocyanates can be used in the form of pure compounds or in modified form, for example in the form of uretdiones, isocyanurates, allophanates or biuret, preferably in the form of reaction products containing urethane groups and isocyanate groups (so-called isocyanate prepolymers).

[0058] In the known prepolymer process, in a first step, the isocyanate component i. is produced from a polyisocyanate P and a polyether polyol PEP in an insufficient amount, based on the functional NCO groups. The prepolymer i. as isocyanate component is then reacted with the further components ii.1), ii.2), ii.3) and ii.4) and optionally ii.5), ii.6), ii.7), ii.8) and / or ii.9) to form the desired product B. Preferably, the polyisocyanate P is a diphenylmethane diisocyanate mixture having an NCO content of 26 to 33.6% by weight NCO, containing isomers of monomeric MDI and higher MDI homologues, and the polyether polyol PEP is a polyether (polypropylene oxide with an OH number of 29 mg KOH / g and a nominal functionality of 6) having an NCO content of 26% by weight and a monomeric MDI content of 55-63% by weight.

[0059] To produce the composite element according to the invention, the polyisocyanates of the isocyanate component i. and the isocyanate-reactive component ii. can be reacted in such amounts that the equivalent ratio of the NCO groups from i. to the sum of the reactive hydrogen atoms from ii. is preferably from 0.3:1 to 1.8:1, particularly preferably from 0.8:1 to 1.5:1 and in particular from 0.9:1 to 1.2:1.

[0060] The reaction for producing the product can be carried out, for example, by means of manual pouring, by means of high-pressure or low-pressure machines or by means of the RIM process (reaction injection molding), usually in open or preferably closed molding tools. Suitable processing machines are commercially available (for example from companies such as Isotherm, Hennecke, Krauss Maffei, etc.).

[0061] Components i. and ii. are usually mixed, depending on the application, at temperatures of 10 to 100° C., preferably 20 to 60° C., and introduced, for example, into a molding tool. The mixing can be carried out on a laboratory scale, for example with the aid of a Pendraulik stirrer, or on a larger scale using conventional high-pressure mixing heads.

[0062] The reaction of the reaction mixture can be carried out, for example, in conventional, preferably temperature-adjustable and closable molds. In particular, when producing products that are as smooth as possible, the molding tools used are preferably those whose surfaces are as smooth as possible or are specially patterned and preferably have no unevenness, cracks, scratches or contamination. The surfaces of these molds can be pretreated, for example, by polishing.

[0063] As molding tools for producing composite elements, conventional and commercially available tools can be used, the surface of which consists, for example, of steel, aluminum, enamel, Teflon, epoxy resin or another polymer material, wherein the surface may optionally have been chrome-plated, for example hard-chrome-plated. The molding tool should preferably be thermostatic in order to be able to set the preferred temperature, should be closable and should have a corresponding design in order to apply pressure to the product. If the molding tool is under pressure, the pressure is usually reduced before opening the mold (for example by unlocking it beforehand and / or by targeted ventilation).

[0064] The reaction for producing the polyisocyanate polyaddition products is usually carried out at a molding temperature of 20 to 220° C., preferably 20 to 120° C., particularly preferably 20 to 60° C. The reaction of the reaction mixture in the molding tool is carried out according to the invention in direct contact with the thermoplastic A. This can be achieved, for example, by placing A. (preferably without wrinkles if A. is a film) into the mold before the reaction, then filling the mold with the reaction mixture and preferably subsequently closing the mold. It is also known to first place the film A. and optionally further components into the mold, then close the mold, and then mix the liquid starting components and inject them into the closed mold.

[0065] In addition to the first polyether polyol ii.1) used according to the invention, other generally known polyether polyols can also be used as component ii.5). The polyether polyols generally have a molecular weight of 300 to 15000 g / mol, in particular 320 to 13000 g / mol, and preferably a functionality of 2 to 6. These can also be copolymers, for example polyether polyols with a proportion of styrene-acrylonitrile copolymers (SAN). In a preferred form, component ii.5) is a glycerol-started polyether polyol, which contains 80% by weight of propylene oxide and 20% by weight of ethylene oxide end blocks, has a solids content of about 42% by weight of a styrene-acrylonitrile copolymer and a hydroxyl number of about 20 mg KOH / g.

[0066] Conventionally known chain extenders and / or crosslinkers can be used as component ii.6). These can, for example, be selected from diethanolamine, triethanolamine, glycerol, 1,2-ethylene glycol, isosorbide and mixtures thereof.

[0067] For example, conventional compounds which accelerate the reaction of component i with the other constituents of component ii., in particular ii.1), ii.2), ii.3), ii.4) and optionally ii.5) and / or ii.6), can be used as catalysts ii.7). Examples which come into consideration include tertiary amines and / or organometallic compounds, in particular tin compounds. The catalysts used are preferably those which lead to the lowest possible misting, i.e. the lowest possible emission of volatile compounds from the reaction product B., for example potassium acetate and / or lithium salts and / or tertiary amines having at least one functional hydroxyl group.

[0068] Conventionally known chemically or physically acting compounds can be used as blowing agents ii.8 for producing foamed products B., for example polyurethane soft, semi-rigid or rigid foams, which may optionally have a urea and / or isocyanurate structure. Water can preferably be used as a chemically acting blowing agent, which forms carbon dioxide by reaction with isocyanate groups. Examples of physical blowing agents, i.e. those inert compounds which evaporate under polyurethane-forming conditions, are, for example, (cyclo)aliphatic hydrocarbons, preferably those having 4 to 8, particularly preferably 4 to 6 and in particular 5 carbon atoms, partially halogenated hydrocarbons or ethers, ketones or acetates. Carbon dioxide (CO 2) can also be used. 2 ), for example, by adding it to at least one of the components of component i or component ii up to its chemical-physical solubility limit. The amount of blowing agent used depends on the target density of the foam. Different blowing agents can be used alone or in any mixture with one another.

[0069] The reaction is optionally carried out in the presence of auxiliaries and / or additives ii.9), such as fillers, fibers (eg in the form of woven fabrics and / or mats), cell regulators, surface-active compounds and / or stabilizers against oxidative, thermal or microbial degradation or aging.

[0070] By using the first polyether polyol ii.1), the composite element according to the invention has in particular a significantly improved adhesion between A. and B. If a plasticizer-containing PVC is used, the adhesion to A. is particularly good. By using the first polyether polyol ii.1) according to the invention, values ​​of adhesion between A. and B. of at least 26 N / 50 mm, preferably at least 27 N / 50 mm, more preferably at least 29 N / 50 mm, when measured according to DIN 53357-A, are achieved. This force is standardized to a unit width of a foam strip of 50 mm according to DIN 53357-A in order to improve the comparability of the measurements. For the present application, samples with a width of 50 mm were produced and investigated.

[0071] The present invention shall be explained in more detail based on the following examples. Embodiment:

[0072] Measuring instruments and standards used:

[0073] Determination of the hydroxyl number according to DIN EN ISO 53240-2: Method using catalysts, November 2007 edition Determination of the NCO content (plastics – polyurethane raw materials) – according to DIN EN ISO 14896, 2009

[0074] Determination of foam density according to DIN 53420

[0075] Determination of the separation force The test was carried out by means of a separation test according to DIN 53357. For this purpose, test specimens with a length of 170 mm and a width of 50 mm were produced. Test speed: 50 mm / min (force determination according to DIN 53357 A; the force per composite element width represents the adhesion (rolling peel resistance)).

[0076] Unless otherwise stated, the values ​​shown in Table 1 are shown in parts by weight.

[0077] The materials and abbreviations used have the following meanings:

[0078] PET A: A glycerol-started polyether polyol containing 87 wt% propylene oxide and 13 wt% ethylene oxide end blocks, with an OH number of 35 mg KOH / g and a nominal functionality of 3

[0079] PET B: A glycerol-started polyether polyol containing 78 wt% propylene oxide and 22 wt% ethylene oxide end blocks, with an OH number of 27.5 mg KOH / g and a nominal functionality of 3

[0080] PET C: A glycerol-started polyether polyol containing 83 wt% propylene oxide and 19 wt% ethylene oxide end blocks, with an OH number of 35 mg KOH / g and a nominal functionality of 3

[0081] PET D: Ethylenediamine-started polyether polyol with 100 wt% propylene oxide, an OH number of 630 mg KOH / g and a nominal functionality of 4

[0082] SAN polyol: a glycerol-started polyether polyol with 80 wt% propylene oxide and 20 wt% ethylene oxide end blocks and a nominal functionality of 3, having a solids content of about 42 wt% styrene-acrylonitrile copolymer and a hydroxyl number of about 20 mg KOH / g, from Covestro Deutschland AG

[0083] Polyester polyol: A polyester polyol based on trimethylolpropane, 1,6-hexanediol, 1,2-propylene glycol and adipic acid with an OH value of 109 mg KOH / g and a nominal functionality of 3.23

[0084] Carbon black: from ISL-Chemie N Black Paste

[0085] Chain extender 1: 1,4-butanediol

[0086] Chain extender 2: diethyltoluenediamine

[0087] Chain extender 3: diethanolamine

[0088] Stabilizer: from Evonik B8734LF2, silicone based

[0089] Catalyst 1: N,N,N'-trimethyl-N'-hydroxyethyl-bis(aminoethyl) ether, from Huntsman

[0090] Catalyst 2: N-[3-(dimethylamino)propyl]urea, from Evonik

[0091] Catalyst 3: A mixture of about 95% by weight of 6-dimethylaminohexanol and about 5% by weight of N-[2-[2-(dimethylamino)ethoxy]ethyl]-N-methyl-1,3-propanediamine from Evonik

[0092] Isocyanate A: diphenylmethane diisocyanate mixture with an NCO content of 32% by weight NCO, comprising 0.05-0.5% by weight of 2,2′-MDI, 5.5-7.5% by weight of 2,4′-MDI, 50-54% by weight of 4,4′-MDI and higher MDI homologues, from Covestro Deutschland AG

[0093] Isocyanate B: Polyisocyanate based on diphenylmethane diisocyanate and a sorbitol-started polyether (polypropylene oxide with an OH number of 29 mg KOH / g and a nominal functionality of 6) with an NCO content of 26% by weight and a monomeric MDI content of 55-63% by weight, from Covestro Deutschland AG.

[0094] The film used was produced by the slush molding process and was based on a skin of PVC powder of the type DSY260 / 02 from Nakan.

[0095] Table 1

[0096]

[0097] Production of composite components

[0098] The composite element has a size of 200×200×10mm3 The PVC film (200×200×1.1 mm 3 ) is placed at the bottom of the mold. The ingredients of the isocyanate-reactive component are first mixed with a stirrer in a 200-liter bucket for about 1 hour so that there are 150 kg of a uniform polyol formulation (isocyanate-reactive component). Both components (isocyanate-reactive component and isocyanate component) are then filled into a high-pressure system and the temperature is set to 30° C. in each case. The two components are then mixed using a high-pressure mixing head at a component pressure of 150 bar. The reaction mixture thus obtained is applied to an open mold, the mold is closed, wherein the amount of the reaction mixture is selected so that the average density of the foam is 120 kg / m 3 De-molding was carried out after about 10 minutes and the composite element was stored at room temperature for 24 hours. Strips with a width of 50 mm were subsequently cut out. The adhesive properties (adhesion between PVC film and polyurethane) of these strips were tested.

[0099] It is clear from the experiments that composite elements according to the invention which contain the polyether polyol according to the invention have significantly higher adhesion between thermoplastic and polyisocyanate polyaddition product than composite elements not according to the invention.

Claims

1. A composite element comprising A. Thermoplastic, B is connected to A by adhesion B. The reaction product of a reaction mixture comprising: i. an isocyanate component comprising one or more polyisocyanates, ii. an isocyanate-reactive component comprising ii.1) a first polyether polyol having a molecular weight of at least 6000 g / mol, obtained by reacting a starter molecule or a mixture of starter molecules having an OH functionality of 1.8 to 3.5 with ethylene oxide and propylene oxide, wherein the proportion of ethylene oxide in the first polyether polyol is 10-28% by weight, based on the total amount of ethylene oxide and propylene oxide, ii.2) one or more polyester polyols having a functionality of greater than 2 and a hydroxyl number of 60-150 mg KOH / g, based on the condensation of adipic acid with 1,2-propylene glycol and at least one other compound having at least two hydroxyl groups, ii.3) 1,4-butanediol, ii.4) diethyltoluenediamine, ii.5) optionally, other polyether polyols, ii.6) optionally, a chain extender and / or a crosslinker, ii.7) optionally, a catalyst, ii.8) optionally, a blowing agent, ii.9) Optionally, auxiliaries and / or additives.

2. The composite element as claimed in claim 1, wherein the reaction product of the reaction mixture has a relative humidity of 155 kg / m 3 Density of 200 g / cm2 or less, determined according to DIN 53420.

3. The composite member as claimed in claim 1, wherein the reaction product of the reaction mixture has a relative humidity of 100 to 130 kg / m 3 The density of the composite is determined according to DIN 53420.

4. The composite element as claimed in claim 1 , wherein the proportion of ii.1) is 50-90% by weight and / or the proportion of ii.2) is 0.1-10% by weight and / or the proportion of ii.3) is 0.1-2.0% by weight and / or the proportion of ii.4) is 0.01-2.0% by weight, in each case based on the total amount of the isocyanate-reactive component ii.

5. The composite element as claimed in any one of claims 1 to 2, wherein the first polyether polyol ii.1) has a molecular weight of 6000-10000 g / mol.

6. The composite element as claimed in any one of claims 1 to 2, wherein the first polyether polyol ii.1) has a molecular weight of 6100-6300 g / mol.

7. The composite element according to any one of claims 1 to 2, wherein: For the first polyether polyol ii.1), the proportion of ethylene oxide, based on the total amount of ethylene oxide and propylene oxide, is 15-25% by weight.

8. The composite element according to any one of claims 1 to 2, wherein: For the first polyether polyol ii.1), the proportion of ethylene oxide, based on the total amount of ethylene oxide and propylene oxide, is 18-23% by weight.

9. The composite element according to any one of claims 1 to 2, wherein: For the first polyether polyol ii.1), the starter molecule is selected from ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 4,4'-dihydroxydiphenylpropane, glycerol, trimethylolpropane, erythritol, sorbitol, ammonia, ethylenediamine, aniline, ethanolamine and triethanolamine and mixtures of at least two of the compounds mentioned.

10. The composite element according to any one of claims 1 to 2, wherein: For the one or more polyester polyols ii.2), the at least one other compound having at least two hydroxyl groups is selected from ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol and trimethylolpropane and mixtures thereof.

11. The composite element according to any one of claims 1 to 2, wherein: For the one or more polyester polyols ii.2), the at least one further compound having at least two hydroxyl groups consists of 1,6-hexanediol and trimethylolpropane.

12. The composite element as claimed in any one of claims 1 to 2, wherein the thermoplastic plastic comprises one or more plastics selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), acrylonitrile-styrene-acrylate (ASA), styrene-acrylonitrile (SAN), polycarbonate (PC), thermoplastic polyurethane (TPU), polyvinyl chloride (PVC), thermoplastic polyolefin (TPO), styrene-maleic anhydride copolymer (SMA) and blends thereof.

13. The composite element as claimed in claim 1, wherein the adhesion between the thermoplastic A. and the reaction product B of the reaction mixture is at least 26 N / 50 mm, measured in accordance with DIN 53357A.

14. The composite element as claimed in claim 1, wherein the adhesion between the thermoplastic A. and the reaction product B of the reaction mixture is at least 29 N / 50 mm, measured in accordance with DIN 53357A.

15. A method for producing a composite element as claimed in any one of claims 1 to 14, comprising the steps I. providing a thermoplastic A., an isocyanate component i. and an isocyanate-reactive component ii., II. mixing the isocyanate component i. and the isocyanate-reactive component ii. provided in step I. to obtain a reaction mixture, III. contacting the reaction mixture obtained in step II. with the thermoplastic A. provided in step I. so that the reaction mixture contacts the thermoplastic A., IV. foaming the reaction mixture obtained in step II. while in contact with a thermoplastic to obtain a composite element comprising a thermoplastic A. to which a reaction product B. of the reaction mixture is adhesively connected, V. Demolding the composite element obtained in step IV.

16. Use of a composite element as claimed in any one of claims 1 to 14 in components in vehicle and aircraft construction or in the building industry.

17. Components in vehicle and aircraft construction and in the building industry comprising a composite element as claimed in any one of claims 1 to 14.

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