Process for producing layered systems comprising a polyurethane foam layer

Abstract

The present invention relates to a process for producing a layered structure comprising an object, a polyurethane foam layer, and a substrate, layered structures producible by the process, the use of the layered structure for the insulation of a cooling device, and a polyol component which may be used in the process.

Description

[0001] Process for producing layered systems comprising a polyurethane foam layer

[0002] Description

[0003] The present invention relates to a process for producing a layered structure comprising an object, a polyurethane foam layer, and a substrate, layered structures producible by the process, the use of the layered structure for the insulation of a cooling device, and a polyol component which may be used in the process.

[0004] In automated production processes, it is often necessary to attach objects or layers together. Examples of such objects are vacuum insulation panels in cooling devices such as refrigerators and / or freezers and bitumen sound insulation sheets in dishwashers. Using double-sided adhesive tape is cumbersome and not suitable for an automated process. Moreover, it is only suitable for attaching flat objects or layers together; if here are protrusions, dimples or other three- dimensional structures, double-sided adhesive tape is not a good solution. This is for example the case in cooling devices, in which the wall that the vacuum insulation panel is attached to may have rib-like structures. Liquid adhesives are an option to overcome the downsides of double-sided adhesive tape. However, they often cure too slowly, dripping from the surface to which they are applied if it is rotated immediately after application. This leads to long cycle times in production, lowering the efficiency of production. On the other hand, if the adhesive hardens too quickly, the objects or layers cannot be properly attached together, and the quality of the produced items suffers. Additionally, in applications such as cooling devices it would be desirable to have an adhesive that contributes to the thermal insulation of the device.

[0005] Attaching vacuum insulation panels to cooling devices is known from EP 2705315 B2. It describes a cooling device comprising a vacuum insulation panel that is attached to a boundary wall with a foamable liquid adhesive. A cooling component may be integrated in the foamable liquid adhesive between the boundary wall and the vacuum insulation panel.

[0006] It was the object of the invention to develop an adhesive for attaching objects on substrates that is suitable for use in an automated process. The processing time should be long enough to enable the attaching step. At the same time, the adhesive should not drip after it has been applied even if the object or the substrate to which it was applied is rotated or otherwise moved without a long waiting time after the application of the adhesive. The adhesion should be good even under mechanical stress such as vibrations. The attachment process should not lead to workplace pollution caused by spraying. Moreover, it should be possible to attach the object on the substrate without placing either or both of them into a mold. It should be possible to attach objects on substrates if the object, the substrate, or both have an embossed surface structure and / or comprise protrusions and / or dimples. In this case, the adhesive should fill the structure so that the object and the substrate are attached also in the protrusions, in the dimples and between the protrusions, the dimples and / or both of them. Examples of such structures are ribbed structures and honeycomb structures. The components of the adhesive should be easy to store and should not contain harmful substances. Furthermore, if desired for the application, the adhesive should contribute to thermal insulation.

[0007] The object was surprisingly achieved by a process for forming a layered structure comprising an object, a polyurethane foam layer, and a substrate, the process comprising the steps

[0008] I. preparing a polyurethane foam reaction mixture by mixing at least a. at least one di- or polyisocyanate or mixtures thereof; b. polyols P) comprising b1) at least one polyether polyol P1 ) having a functionality in the range of 3.5-8 and an OH number in the range of 350 to 800 mg KOH / g, wherein at least one starter compound of the polyether polyol P1 ) is a monosaccharide, oligosaccharide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms; b2) at least one polyol P2) having a functionality in the range of 2.5-3.5 and an OH number in the range of 300-450 mg KOH / g; and b3) at least one polyol P3) having a functionality in the range of 1.8-4.1 and an OH number in the range of 40-260 mg KOH / g; and c. 4,4-methylenebis(2,6-diethylaniline); d. at least one blowing agent; e. at least one catalyst; and optionally f. at least one foam stabilizer,

[0009] II. forming a layered structure comprising the object and the substrate, wherein the polyurethane reaction mixture forms an intermediate layer between the object and the substrate; and

[0010] III. curing the reaction mixture to form a polyurethane foam layer.

[0011] The object was likewise achieved by a layered structure comprising an object, a polyurethane foam layer, and a substrate, wherein the layered structure is producible by the process described above as well as by the use of the layered structure prepared according to the process described above or of the layered structure producible of the process described above for the insulation of a cooling device. Moreover, the object was achieved by a polyol component which may be used in the process described above.

[0012] The process according to the invention allows for an efficient attaching of objects on substrates. It is suitable for use in an automated process. The objects and the substrates are attached by a polyurethane reaction mixture which acts as an adhesive. The application of the polyurethane reaction mixture on the object and / or the substrate can be done by pouring instead of spraying. The process thus avoids workplace pollution that would occur if the polyurethane foam reaction mixture was applied by spraying. The polyurethane foam reaction mixture does not drip after application even if the object or the substrate to which it was applied is rotated or otherwise moved. This ensures that the object or the substrate can be moved freely after applying the polyurethane foam reaction mixture. Further, the curing time of the polyurethane foam reaction mixture is short enough for an automated process but long enough to ensure that the polyurethane foam does not harden too early. No long waiting times after the application of the reaction mixture are required, which is crucial for an automated, industrial process. Moreover, the object or the substrate can be handled with a robotic arm or other automated systems and can be moved and rotated freely by them. It is not necessary to place the object, the substrate or both in a mold for the attachment step, which reduces the complexity of the attachment step as well as the number of parts needed in it. The process according to the invention allows for the attachment of objects and substrates even if the object, the substrate, or both do not have a flat surface. For example, the object, the substrate, or both can have have an embossed surface structure and / or comprise protrusions and / or dimples.

[0013] In the following, the invention is described in more detail.

[0014] One aspect of the present invention is a process for forming a layered structure comprising an object, a polyurethane foam layer, and a substrate, the process comprising the steps

[0015] I. preparing a polyurethane foam reaction mixture by mixing at least a. at least one di- or polyisocyanate or mixtures thereof; b. polyols P) comprising b1) at least one polyether polyol P1 ) having a functionality in the range of 3.5-8 and an OH number in the range of 350 to 800 mg KOH / g, wherein at least one starter compound of the polyether polyol P1 ) is a monosaccharide, oligosaccharide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms; b2) at least one polyol P2) having a functionality in the range of 2.5-3.5 and an OH number in the range of 300-450 mg KOH / g; and b3) at least one polyol P3) having a functionality in the range of 1.8-4.1 and an OH number in the range of 40-260 mg KOH / g; and c. 4,4-methylenebis(2,6-diethyleneaniline); d. at least one blowing agent; e. at least one catalyst; and optionally f. at least one foam stabilizer,

[0016] II. forming a layered structure comprising the object and the substrate, wherein the polyurethane reaction mixture forms an intermediate layer between the object and the substrate; and

[0017] III. curing the reaction mixture to form a polyurethane foam layer.

[0018] The term “polyurethane” is known by the person skilled in the art as including not only polymers containing urethane groups but as also including polymers containing no or very low amounts of urethane groups, as long as these polymers are derived from difunctional or polyfunctional isocyanates, see Polyurethane Handbook, 2ndedition 1993, editor Guether Oertel, Carl Hanser Verlag Munich, Chapter 2.1.1. Examples are polyetherureas, polyisocyanurates, polyureas and polycarbodiimides. Polymers containing urethane groups are preferred as polyurethanes.

[0019] The term “polyurethane foam reaction mixture” according to the invention means the polyurethane mixture between the start of mixing the reaction components and the tack-free time of the polyurethane foam material.

[0020] The layered structure according to the invention comprises an object, a polyurethane foam layer, and a substrate.

[0021] The object, the substrate or both may have an embossed surface structure and / or comprise protrusions and / or dimples. N on-exhaustive examples of such structures are ribbed structures and honeycomb structures.

[0022] The object according to the invention is an object that is to be attached to a substrate. The object may be a panel, a board, a mat, a sheet, a foil, or a textile. Preferably, the object may be a vacuum insulation panel, a thermal insulation board, a sound insulation sheet, a wooden panel, a honeycomb sheet such a paper honeycomb sheet, a plastic sheet, a plastic plate, a metal sheet, a metal plate, a textile mat, a glass mat, a mineral wool component such as a mineral wool board, a fiber- re info reed composite component, a fiberglass component, a foil, a textile, a sheet molding compound (SMC) component, or a bulk molding compound (BMC) component. Preferably, the object is a vacuum insulation panel, a thermal insulation board, a sound insulation sheet, or a honeycomb sheet such as a paper honeycomb sheet.

[0023] Preferably, the object is a vacuum insulation panel or a sound insulation sheet. The sound insulation sheet may be a bitumen sound insulation sheet. Particularly preferred, the object is a vacuum insulation panel.

[0024] The substrate according to the invention is a substrate that the object is to be attached to. The substrate may be a wall, a door, a roof, an inner side, an outer side, a bottom side, or a top side. The substrate may be a part of a cooling device such as a refrigerator, a freezer or a refrigerator-freezer combination, a dishwasher, a car, a tractor, an agricultural machine, a camper, a caravan, a trailer, or a truck trailer. “A part” means a whole substrate or a part of a substrate of a part of an aforementioned device. The substrate may be a wall, a door, a roof, an inner side, an outer side, a bottom side, or a top side of a cooling device such as a refrigerator, a freezer or a refrigerator-freezer combination, a dishwasher, a car, a tractor, an agricultural machine, a camper, a caravan, a trailer, or a truck trailer.

[0025] Preferably, the substrate is an outer wall of a cooling device, a wall of an inner container of a cooling device, an outer wall of a door of a cooling device, an inner wall of a door of a cooling device, an inliner of a door of a cooling device, an outer wall of a dishwasher, or a wall of an inner container of a dishwasher.

[0026] Preferably, the substrate is an outer wall of a cooling device, a wall of an inner container of a cooling device, an outer wall of a door of a cooling device, an inner wall of a door of a cooling device, or an inliner of a door of a cooling device.

[0027] Preferably, the object is a vacuum insulation panel and the substrate is an outer wall of a cooling device, a wall of an inner container of a cooling device, an inner wall of a door of a cooling device, an outer wall of a door of a cooling device, or an inliner of a door of a cooling device. The cooling device may be a refrigerator, a freezer, and / or a refrigerator-freezer combination.

[0028] Preferably, the object is a sound insulation sheet and the substrate is the inside of an outer wall of a dishwasher, or the outside of a wall of an inner container of a dishwasher.

[0029] Preferably, one or several steps of the process according to the invention may be automated. The process according to the invention is preferably an automated process. In step I of the invention, a polyurethane foam reaction mixture is prepared.

[0030] The polyurethane foam reaction mixture is prepared by mixing at least at least one di- or polyisocyanate or mixtures thereof; polyols P) comprising polyols P1), P2), and P3) that are described below; 4,4-methylenebis(2,6-diethyleneaniline); at least one blowing agent; at least one catalyst; and optionally at least one foam stabilizer. In a preferred embodiment, also additives and / or auxiliaries may be mixed with the other components of the foam reaction mixture.

[0031] Di- or polyisocyanate (a)

[0032] The di- or polyisocyanates or mixtures thereof (a) used may include any aliphatic, cycloaliphatic, and aromatic di- or polyfunctional isocyanates known from the prior art and any desired mixture of these. The di- or polyisocyanates can optionally be modified.

[0033] Specific examples include alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene radical, such as dodecane 1 ,12-diisocyanate, 2-ethyltetramethylene 1 ,4-diisocyanate, 2- methylpentamethylene 1 ,5-diisocyanate, tetramethylene 1 ,4-diisocyanate and preferably hexamethylene 1 ,6-diisocyanate; cycloaliphatic diisocyanates such as cyclohexane 1 ,3- and 1 ,4- diisocyanate and also any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocy- anatomethylcyclohexane (IPDI), hexahydrotolylene 2,4- and 2,6-diisocyanate and also the corresponding isomer mixtures, dicyclohexylmethane 4,4'-, 2,2'- and 2,4'-diisocyanate and also the corresponding isomer mixtures, and preferably aromatic di- and polyisocyanates such as, for example, tolylene 2,4- and 2,6-diisocyanate and the corresponding isomer mixtures, methylene diphenyl 4,4'-, 2,4'- and 2,2'-diisocyanate and the corresponding isomer mixtures, mixtures of methylene diphenyl 4,4'- and 2,4'-diisocyanates, polyphenylpolymethylene polyisocyanates, mixtures of methylene diphenyl 4,4'-, 2,4'- and 2,2'-diisocyanates and polyphenylpolymethylene polyisocyanates (polymeric MDI or PM DI) and mixtures of polymeric MDI and tolylene diisocyanates. The di- or polyisocyanates can be used individually or in the form of their mixtures.

[0034] Use is frequently also made of modified polyfunctional isocyanates, i.e. products which are obtained by chemical reaction of organic polyisocyanates. Examples which may be mentioned are polyisocyanates comprising ester, urea, biuret, allophanate, carbodiimide, isocyanurate, uretdi- one, carbamate and / or urethane groups.

[0035] The polyisocyanates can also be applied in form of prepolymers. These polyisocyanate prepolymers are obtained by reacting the above-described polyisocyanates with compounds having at least two groups reactive towards isocyanate to form a prepolymer. Furthermore, prepolymers and mixtures of the above-described isocyanates and prepolymers can be used as the isocyanate (a). These polyisocyanate prepolymers are obtainable by reacting polyisocyanates described above in excess with compounds having at least two groups reactive toward isocyanates to give the prepolymer. The reaction may take place at temperatures of 30 to 100 °C, for example, preferably at about 45 to 60 °C. The prepolymers usually have an NCO content in the range of 14 to 32 wt.-%, preferably in the range of 25 to 30 wt.-%.

[0036] The compounds having at least two groups reactive towards isocyanate are known and are described in, for example, “Polyurethane Handbook”, Carl Hanser Publishers, 2nd edition 1993, chapter 3.1. For example, polyether polyols and polyester polyols can be applied as compunds having at least two groups reactive towards isocyanate in the preparation of the prepolymers.

[0037] Preferably, the compounds having at least two groups reactive towards isocyanate are polyether polyols and / or polyester polyols containing OH groups deriving from propylene oxide, for example. The polyether polyols and / or polyester polyols preferably have a functionality in the range of 2 to 4, particularly preferably in the range of 2 to 3. Particularly preferably, the compounds having at least two groups reactive towards isocyanate are polyester polyols.

[0038] Preferred di- or polyisocyanates (a) are tolylene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), mixtures of methylene diphenyl diisocyanate and polyphenylpolymethylene polyisocyanates (polymeric MDI or PM DI) and / or related isocyanate prepolymers. Particularly preferably, the at least one di- or polyisocyanate is selected from the group consisting of methylene diphenyl diisocyanate and / or polymeric MDI and / or related isocyanate prepolymers.

[0039] Very particular preference is given to employing polymeric MDI.

[0040] Preferred prepolymers are mixtures of polymeric MDI and polyester polyols. Very particular preference is given to a prepolymer comprising the reaction product of polymeric MDI and a polyester polyol containing monomeric units derived from dicarboxylic acids, fatty acids, and polyfunctional alcohols.

[0041] In one preferred configuration, the prepolymer comprises the reaction product of 92-97 wt.-% of polymeric MDI and 3-8 wt.-% of a polyester polyol containing monomeric units derived from dicarboxylic acids, fatty acids, and polyfunctional alcohols. If isocyanate prepolymers are used as isocyanates, the content of compounds having groups which are reactive toward isocyanates is calculated with inclusion of the compounds having groups which are reactive toward isocyanates used for preparing the isocyanate prepolymers.

[0042] Polyols P) (b)

[0043] The OH number (hydroxyl number) can be determined by means of well-established methods. By way of example, the OH number can be determined according to DIN 53240 (1971-12).

[0044] The functionality of a polyol, especially of the polyols P1), P2), and P3) and other polyols to be used according to the invention, within the context of the present invention means the number of alkylene oxide reactive hydrogen atoms per mole of starter compound or per mole of mixture of the starter compounds prior to the time of alkylene oxide metering. The time of the alkylene oxide metering is in this case the start of the addition of the alkylene oxide component to the starter compound(s). The calculation takes into account all alkylene oxide-reactive hydrogen atoms of the starter compound(s) that are present in the starter mixture.

[0045] The functionality F in the context of the present invention is calculated according to the following formula (I): til = moles of starter i ft = functionality of starter i m = number of starters in the starter mixture

[0046] F = functionality

[0047] The functionality F of a polyol produced from a mixture of two starter compounds (m=2) is calculated as follows:

[0048] F = (moles of starter compound A * functionality of starter compound A + moles of starter compound B * functionality of starter compound B) / (moles of starter A + moles of starter B).

[0049] The formula can be amended accordingly for other starter compounds. Thus, for example, a polyether polyol has a functionality of 5.12 when 626.48 mol of glycerol (functionality 3), 559.74 mol of sucrose (functionality 8) and 67.31 mol of dimethylethanolamine (functionality 1) are used.

[0050] The functionality F determined by the formula presented above is also called equivalent functionality or average functionality and is known to those skilled in the art as a readily accessible method for determining the functionality of polyols, see M. lonescu “Chemistry and Technology of Polyols for Polyurethanes”, 2005, Rapra Technology Limited, pages 34 to 39.

[0051] The functionality of the polyether polyols P1), P2), and P3) as well as other polyols, as defined above according to the invention, can differ from the functionality after commencement of the addition of at least one alkylene oxide, that is, during the reaction of the at least one alkylene oxide with a starter compound, or of the reaction product, since during the reaction there is formation of by-products such as glycols and unsaturated monofunctional constituents. The sidereactions are known in the literature. The functionality of the polyether polyols P1), P2), and P3) as well as other polyols can thus also be referred to as the functionality of the starter compound or starter compound mixture used for the preparation of the respective polyol.

[0052] A polyol in the context of the present invention is an organic compound that contains at least two hydrogen atoms that are reactive towards isocyanate. Examples of polyols are polyether polyols, polyester polyols, polyether ester polyols, polymer polyols and polycarbonate polyols. Polyols are prepared by alkoxylation of one or several starter compounds; the reaction of the starter compounds and alkylene oxides as well as the preparation of polyols per se is known to those skilled in the art. The starter compounds are compounds having active hydrogen atoms. In the reaction with the alkylene oxides, the alkylene oxides are added to the starter compound^), this possibly taking place with use of a catalyst. One or several starter compounds can take part in the reaction. This reaction is known per se to those skilled in the art. Starter compounds are often also called starter molecules, starting compounds, or starters.

[0053] A polyether polyol in the context of the present invention is an organic compound that contains at least ether and OH groups as functional groups. Polyether polyols are reaction products of starter compounds with at least two alkylene oxide reactive hydrogen atoms with alkylene oxides. Starter compounds for polyether polyols include compounds with at least two OH groups as well as polyamines with at least two NH2 groups. The preparation of polyether polyols is known per se to those skilled in the art.

[0054] Preference is given to using one or more compounds having from 2 to 4 carbon atoms in the alkylene radical, also called C2 to C4 alkylene oxides, e.g. ethylene oxide, 1,2-propylene oxide, tetra hydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, in each case either alone or in the form of mixtures, particularly preferably ethylene oxide and / or 1,2-propylene oxide, as alkylene oxides.

[0055] The polyols P) according to the present invention comprise at least one polyether polyol P1), at least one polyol P2), and at least one polyol P3). The polyols P) preferably additionally comprise at least one polyol P4).

[0056] Polyether polyol P1)

[0057] At least one starter compound of polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms. Additionally, also other starter compounds may be used. Possible starter compounds of polyol P1) are monosaccharides, oligosaccharides, polysaccharides, sugar alcohols that all have at least 4 active hydrogen atoms, polyhydric alcohols, mixtures thereof, and alkoxylation products of the aforementioned compounds.

[0058] Preferably, the polyether polyol P1) is an alkoxylation product of monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polyhydric alcohols, mixtures thereof, and alkoxylation products of the aforementioned compounds with C2 to C4 alkylene oxides, wherein at least one starter compound is a monosaccharide, oligosaccharide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms. The C2 to C4 alkylene oxides are preferably selected from ethylene oxide and / or propylene oxide and / or mixtures of ethylene oxide and propylene oxide.

[0059] The monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polyhydric alcohols and mixtures thereof can be reacted with alkylene oxides as described above to form alkoxylation products. The alkoxylation products are usually prepared using C2 to C4 alkylene oxides, preferably using ethylene oxide and / or propylene oxide. The alkoxylation products are then once again reacted, as starter compounds, with alkylene oxides in the preparation of the polyether polyols P1), possibly in presence of further starter compounds. The use of the alkoxylation products as starter compounds is particularly advantageous when further starter compounds which are initially present as a solid or have a high viscosity are employed. Alkoxylation products of monosaccharides, oligosaccharides, polysaccharides, polyhydric alcohols or mixtures thereof are preferably added during the preparation of the polyetherols (P1) for the reduction of viscosity. When calculating the functionality of the polyether polyol P1) according to the invention, the above-mentioned alkoxylation products are correspondingly taken into account.

[0060] Examples of suitable starter compounds of the polyether polyol P1) are sugar derivatives such as sucrose, lactose, maltose, glucose, allose, altrose, gulose, idose, galactose, talose, fructose, sorbose, tagatose, mannose, psicose, hexitol derivatives such as sorbitol, mannitol, and other dihydric or polyhydric alcohols like ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, butane-1 ,4-diol, butane-1 ,3-diol, butane-1 ,2-diol, butane-2,3-diol, butane-1 ,2,4-triol, pentane-1 ,3,5-triol, erythritol, and pentaerythritol, wherein at least one starter compound is a monosaccharide, oligosac- charide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms.

[0061] Preferably, the monosaccharides, oligosaccharides, polysaccharides and / or sugar alcohols that have at least 4 active hydrogen atoms are selected from the group consisting of sucrose, lactose, maltose, glucose, allose, altrose, gulose, idose, galactose, talose, fructose, sorbose, taga- tose, mannose, psicose, erythritol, pefrtaefythflto -and sorbitol. Particularly preferred are sucrose and sorbitol. Sucrose is very particularly preferred.

[0062] It is preferred that at least one starter compound of the polyether polyol P1) is a polyhydric alcohol having 2-3 active hydrogen atoms. Preferably, at least one starter compound of the poly- ether polyol P1) is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, butane-1 ,4-diol, butane-1 ,3-diol, butane-1 ,2-diol, butane-2,3-diol, butane-1 ,2,4-triol, and pentane-1 ,3,5-triol. Particularly preferred polyhydric alcohols are diethylene glycol, dipropylene glycol, trimethylpropane, and glycerol; glycerol is very particularly preferred.

[0063] In a preferred embodiment, the starter compounds of the polyether polyol (P1) are selected from sucrose and sorbitol with glycerol as a second starter. Particularly preferred are starter mixtures comprising glycerol and sucrose. Basic compounds are employed in most cases as alkoxylation catalysts for the reaction of the starter compound(s) with alkylene oxide(s). In industrial processes, these are mostly hydroxides of alkali metals, such as for example sodium, cesium or in particular potassium hydroxide. Alkali metal alkoxides, such as for example sodium methoxide, sodium or potassium methoxide or potassium isopropoxide, are known as catalysts. Preparation can also be affected with amine catalysts.

[0064] The amine catalysts are preferably selected from the group comprising trialkylamines, such as for example trimethylamine, triethylamine, tripropylamine and tributylamine; dimethylalkylamines, such as for example dimethylethanolamine, dimethylcyclohexylamine, dimethylethylamine and dimethylbutylamine; aromatic amines, such as for example dimethylaniline, dimethylaminopyridine, dimethylbenzylamine, pyridine, imidazoles, such as for example imidazole, 4(5)- methylimidazole, 3-methylimidazole and 1 -hydroxypropylimidazole; guanidines and amidines, such as for example 1 ,5-diazabicyclo[4.3.0]non-5-ene and 1 ,5-diazabicyclo[5.4.0]undec-7-ene. The catalyst is preferably selected from dimethylethanolamine and imidazole.

[0065] The adduct formation with the alkylene oxides is preferably conducted at a temperature between 90 and 150°C and a pressure between 0.1 to 8 bar. The metering of the alkylene oxides is typically followed by a post-addition phase, in which the alkylene oxide is depleted by reaction. If necessary, a post-reaction phase can follow thereafter. Distillation typically follows to separate off volatile constituents, preferably under reduced pressure.

[0066] The functionality of the polyether polyol P1) is at least 3.5, preferably at least 3.7, more preferred at least 3.9, even more preferred at least 4.0. The functionality of the polyether polyol (P1) is at most 8.0. , preferably at most 7.9., more preferred at most 7.0, even more preferred at most 6.5. The functionality of the polyether polyol P1) is in the range of 3.5 to 8, preferably in the range of 3.7 to 7.9, more preferred 3.9 to 7.0, even more preferred 4.0 to 6.5.

[0067] The OH number of the polyether polyol P1) is at least 350 mg KOH / g, preferably at least 370 mg KOH / g, more preferred at least 390 mg KOH / g, even more preferred at least 400 mg KOH / g. The OH number of the polyether polyol (P1) is at most 800 mg KOH / g, preferably at most 650mg KOH / g, more preferred at most 550 mg KOH / g, even more preferred at most 510 mg KOH / g. The OH number of the polyether polyol P1) is in the range of 350 to 800 mg KOH / g, preferably in the range of 370 to 650 mg KOH / g, more preferred in the range of 390 to 550 mg, even more preferred in the range of 400 to 510 mg KOH / g.

[0068] In a preferred configuration, the functionality of the polyether polyol P1) is in the range of 3.5 to 8.0 and the OH number in the range of 350 to 800 mg KOH / g, more preferred the functionality is in the range of from 3.7 to 7.9 and the OH value in the range of from 370 to 650 mg KOH / g, even more preferred the functionality is in the range of from 3.9 to 7.0 and the OH value in the range of from 390 to 550 mg KOH / g, in particular the functionality is in the range of 4.0 to 6.5 and the OH value in the range of from 400 to 510 mg KOH / g.

[0069] Polyol P2)

[0070] The polyol P2) is preferably a reaction product of amines, polyhydric alcohols, alkoxylation products of the aforementioned compounds, and / or mixtures thereof with C2 to C4 alkylene oxides. Possible starter compounds for the polyether polyol P2) are, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, butane-1 ,4-diol, butane-1 ,3-diol, butane-1 ,2-diol, butane-2,3-diol,butane- 1 ,2,4-triol, pentane-1 ,3,5-triol, erythritol, pentaerythritol, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine, in particular vicinal toluenediamine, naphthylamine, ethylenediamine, di-ethylenetriamine, 4,4'-methylenedianiline, 1 ,3, -pro- panediamine, 1 ,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other dihydric or polyhydric alcohols or monofunctional or polyfunctional amines.

[0071] Polyhydric alcohols are preferred starter compounds of the polyol P2). Preferably, the polyol P2) is a reaction product of polyhydric alcohols, alkoxylation products of polyhydric alcohols, and / or mixtures thereof with C2 to C4 alkylene oxides. Preferably, the polyol P2) is a reaction product of glycerol, trimethylolpropane, alkoxylation products of the aforementioned compounds and / or mixtures thereof with C2 to C4 alkylene oxides. Particularly preferably, the polyol P2) is a reaction product of glycerol, trimethylolpropane, alkoxylation products of the aforementioned compounds and / or mixtures thereof with ethylene oxide, propylene oxide or mixtures of ethylene oxide and propylene oxide.

[0072] The polyol P2) has an OH number of at least 300 mg KOH / g, preferably at least 330 mg KOH / g, more preferred at least 360 mg KOH / g. The polyether polyol P2) has an OH number of at most 450 mg KOH / g, preferably at most 430 mg KOH / g, more preferred at most 410 mg KOH / g. It is preferred that the OH number of the polyether polyol P2) is in the range of 300 to 450 mg KOH / g, more preferred in the range of 330 to 430 mg KOH / g, even more preferred in the range of 360 to 410 mg KOH / g.

[0073] The polyether polyol P2) has a functionality of at least 2.5, preferably at least 2.6, more preferred at least 2.8. The polyol P2) has a functionality of at most 3.5, preferably at most 3.4, more preferred at most 3.3. The functionality of the polyether polyol (P2) is in the range of 2.5 to 3.5, preferably in the range of 2.6 to 3.4, more preferred in the range of 2.8 to 3.3. In a preferred configuration, the polyol P2) has a functionality in the range of 2.5 to 3.5 and an OH number in the range of 300 to 450 mg KOH / g, more preferred the polyol P2) has a functionality in the range of 2.5 to 3.5 and an OH number in the range of 330 to 430 mg KOH / g, even more preferred the polyol P2) has a functionality in the range of 2.8 to 3.3 and an OH number in the range of 360 to 410 mg KOH / g.

[0074] Polyol P3)

[0075] The polyol P3) is preferably a reaction product of amines, polyhydric alcohols, alkoxylation products of the aforementioned compounds or mixtures thereof with C2 to C4 alkylene oxides. Possible starter compounds for the polyether polyol P3) are, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, butane-1 ,4-diol, butane-1 ,3-diol, butane-1 ,2-diol, butane-2,3-diol,butane- 1 ,2,4-triol, pentane-1 ,3,5-triol, methylamine, ethylamine, dimethylaminopropylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine, in particular vicinal toluenediamine, naphthylamine, ethylenediamine, di-ethylenetriamine, 4,4'-methylenedianiline, 1 ,3, -pro- panediamine, 1 ,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other dihydric or polyhydric alcohols or monofunctional or polyfunctional amines.

[0076] Preferably, the polyol P3) is a reaction product of amines, polyhydric alcohols, alkoxylation products of polyhydric alcohols, and / or mixtures thereof with ethylene oxide, propylene oxide and / or mixtures of ethylene oxide and propylene oxide. Preferably, the polyol P3) is a reaction product of propylene glycol, ethylene glycol, glycerol, trimethylolpropane, toluenediamine, alkoxylation products of the aforementioned compounds and / or mixtures thereof with ethylene oxide, propylene oxide and / or mixtures of ethylene oxide and propylene oxide. Particularly preferably, the polyol P3) is a reaction product of propylene glycol, glycerin, thrimethylolpropane, toluenediamine, alkoxylation products of the aforementioned compounds or mixtures thereof with ethylene oxide, propylene oxide and / or mixtures of ethylene oxide and propylene oxide.

[0077] The polyol P3) has an OH number of at least 40 mg KOH / g, preferably at least 45 mg KOH / g. The polyether polyol P3) has an OH number of at most 260 mg KOH / g, preferably at most 250 mg KOH / g, more preferred at most 200 mg KOH / g. It is preferred that the OH number of the polyether polyol P3) is in the range of 40 to 260 mg KOH / g, more preferred in the range of 45 to 250 mg KOH / g, even more preferred in the range of 45 to 200 mg KOH / g.

[0078] The polyether polyol P3) has a functionality of at least 1.8, preferably at least 1.9. The polyol

[0079] P3) has a functionality of at most 4.1 , preferably at most 3.9, more preferred at most 3.2. The functionality of the polyether polyol P3) is in the range of 1 .8 to 4.1 , preferably in the range of 1.9 to 3.9, more preferred in the range of 1.9 to 3.2.

[0080] In a preferred configuration, the polyol P3) has a functionality in the range of 1.8 to 4.1 and an OH number in the range of 40 to 260 mg KOH / g, more preferred the polyol P3) has a functionality in the range of 1 .9 to 3.9 and an OH number in the range of 45 to 250 mg KOH / g, even more preferred the polyol P3) has a functionality in the range of 1.9 to 3.2 and an OH number in the range of 45 to 200 mg KOH / g.

[0081] Polyol P4)

[0082] The polyol P4) is a reaction product of amines with C2 to C4 alkylene oxides. Preferably, the polyol P4) is a reaction product of ethylenediamine, toluenediamine and / or dimethylaminopropylamine with ethylene oxide, propylene oxide or mixtures of ethylene oxide and propylene oxide. Particularly preferred, the polyol P4) is a reaction product of ethylenediamine with ethylene oxide, propylene oxide or mixtures of ethylene oxide and propylene oxide.

[0083] The polyol P4) has an OH number of at least 600 mg KOH / g, preferably at least 630 mg KOH / g, more preferred at least 660 mg KOH / g. The polyether polyol P4) has an OH number of at most 800 mg KOH / g, preferably at most 790 mg KOH / g, more preferred at most 780 mg KOH / g. It is preferred that the OH number of the polyether polyol P4) is in the range of 600 to 800 mg KOH / g, more preferred in the range of 630 to 790 mg KOH / g, even more preferred in the range of 660 to 780 mg KOH / g.

[0084] Based on the total weight of the polyols P), the amount of the at least one polyether polyol P1) is preferably at least 20 wt.-%, more preferred at least 25 wt.-%, even more preferred at least 30 wt.-%. Based on the total weight of the polyols P), the amount of the at least one polyether polyol P1) is preferably at most 60 wt.-%, more preferred at most 55 wt.-%, even more preferred at most 50 wt.-%. Preferably, the amount of the at least one polyether polyol P1) is 20-60 wt.-%, more preferred 25-55 wt.-%, even more preferred 30-50 wt.-%, based on the total weight of the polyols P).

[0085] Based on the total weight of the polyols P), the amount of the at least one polyol P2) is preferably at least 20 wt.-%, more preferred at least 25 wt.-%, even more preferred at least 30 wt.-%. Based on the total weight of the polyols P), the amount of the at least one polyether polyol P1) is preferably at most 60 wt.-%, more preferred at most 55 wt.-%, even more preferred at most 50 wt.-%. Preferably, the amount of the at least one polyol P2) is 20-60 wt.-%, more preferred 25-55 wt.-%, even more preferred 30-50 wt.-%, based on the total weight of the polyols P).

[0086] Based on the total weight of the polyols P), the amount of the at least one polyol P3) is preferably at least 5 wt.-%, more preferred at least 6 wt.-%, even more preferred at least 8wt.-%. Based on the total weight of the polyols P), the amount of the at least one polyol P3) is preferably at most 20 wt.-%, more preferred at most 18wt.-%, even more preferred at most 16 wt.-%. Preferably, the amount of the at least one polyol P3) is 5-20 wt.-%, more preferred 6-18 wt.-%, even more preferred 8-16wt.-%, based on the total weight of the polyols P).

[0087] In case the polyols P) comprise at least one polyol P4), the amount of the at least one polyol P4) is preferably at least >0 wt.-%, more preferred at least 5 wt.-%, even more preferred at least 10 wt.-%, based on the total weight of the polyols P). In case the polyols P) comprise at least one polyol P4), the amount of the at least one polyol P4) is preferably at most 22 wt.-%, more preferred at most 20 wt.-%, even more preferred at most 18 wt.-%, based on the total weight of the polyols P). In case the polyols comprise at least one polyol P4), The amount of the at least one polyol P4) is preferably >0-22 wt.-%, more preferred 5-20 wt.-%, even more preferred 10-18 wt.-%, based on the total weight of the polyols P).

[0088] In a preferred embodiment, the amount of the at least one polyether polyol P1) is 20-60 wt.-%, the amount of the at least one polyol P2) is 20-60 wt.-%, and the amount of the at least one polyol P3) is 5-20 wt.-%, wherein all amounts are based on the total weight of the polyols P).

[0089] In a preferred embodiment, the amount of the at least one polyether polyol P1) is 20-60 wt.-%, the amount of the at least one polyol P2) is 20-60 wt.-%, the amount of the at least one polyol P3) is 5-20 wt.-%, and the amount of the at least one polyol P4) is >0-22 wt.-%, wherein all amounts are based on the total weight of the polyols P).

[0090] The polyols P) may comprise additional polyols other than P1) to P4). The amount of polyols other than P1) to P4) is preferably 0-25 %, more preferred 0-15 %, even more preferred 0-10 %. Preferably, the polyols P) do not comprise additional polyols other than P1) to P4).

[0091] 4,4-methylenebis(2,6-diethyleneaniline) (c)

[0092] The amount of 4,4-methylenebis(2,6-diethyleneaniline) is preferably at least 0.2 wt.-%, more preferably at least 0.4 wt.-%, particularly preferred at least 0.5 wt.-%, based on the total amount of all components that are reacted with the at least one di- or polyisocyanate or mixtures thereof. The amount of 4,4-methylenebis(2,6-diethyleneaniline) is preferably at most 5 wt.-%, more preferably at most 4 wt.-%, particularly preferred at most 3 wt.-%, based on the total weight of all components that are mixed with the at least one di- or polyisocyanate or mixtures thereof.

[0093] The amount of 4,4-methylenebis(2,6-diethyleneaniline) is preferably in the range of 0.2-5 wt.-%, more preferred in the range of 0.4-4 wt.-%, even more preferred in the range of 0.5-3 wt.-%, based on the total weight of all components that are mixed with the at least one di- or polyisocyanate or mixtures thereof.

[0094] Blowing agent (d)

[0095] The blowing agent can be a chemical blowing agent, a physical blowing agent or a mixture of chemical and physical blowing agents. “Chemical blowing agent” is understood to mean compounds that form gaseous products by reaction with isocyanate. Examples of chemical blowing agents are water and acids, in particular water, formic acid and mixtures of water and acids. Water is a preferred chemical blowing agent.

[0096] Preferably, the blowing agent comprises water.

[0097] Based on the total weight of all components that are mixed with the at least one di- or polyisocyanate or mixtures thereof, the amount of water is preferably at least 0.5 wt.-%, preferably at least 0.6 wt.-%, more preferred at least 0.7 wt.-%. The amount of water is preferably at most 5 wt.-%, more preferred at most 4 wt.-%, even more preferred at most 3 wt.-%. Preferably, the amount of water is in the range of 0.5 wt.-% to 5 wt.-%, more preferred in the range of 0.6 wt.-% to 4 wt.-%, even more preferred in the range of 0.7 wt.-% to 3 wt.-%.

[0098] The blowing agent may comprise water and at least one further chemical blowing agent. Preferably, the total amount of chemical blowing agents is at least 0.5 wt.-%, more preferably at least 0.6wt.-%, even more preferably at least 0.7wt.-% based on the total amount of the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof. The total amount of chemical blowing agents is preferably at most 6 wt.-%, more preferably at most 5 wt.-%, even more preferably at most 4 wt.-% based on the total amount of the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof. It is particularly preferred that water is the sole chemical blowing agent. One advantage of using water instead of other chemical blowing agents such as formic acid or other acids is the easy processing without a need for safety measures.

[0099] Preferably, the blowing agent comprises water and a physical blowing agent. Suitable physical blowing agents that can be used are in general all hydrocarbons known to those skilled in the art as blowing agents, for example non-halogenated hydrocarbons and halogenated, preferably fluorinated, alkenes.

[0100] Examples of fluorinated alkenes are propenes, butenes, pentenes and hexenes having 3 to 6 fluorine substituents, where other substituents such as chlorine may be present, for example tetrafluoropropenes, fluorochloropropenes, for example trifluoromonochloropropenes, pentafluoropropenes, fluorochlorobunetes, hexafluorobutenes or mixtures thereof. Preference is given to 1,1,1,3-tetrafluoropropene, 1 ,1,1-trifluoro-2-chloropropene, 1-chloro-3,3,3-trifluoropro- pene, 1,1 ,1 ,2,3-pentafluoropropene, Z-1,1 ,1 ,4,4,4-hexafluoro-2-butene, E-1,1 ,1 ,4,4,4-hex- afluoro-2-butene, 1 -brompentafluoropropene, 2-brompentafluoropropene, 3-brompentafluoro- propene, 1,1,2,3,3,4,4-heptafluoro-1-butene, 1-chloro-2,3,3,3-tetrafluoropropene, 1-brom- 2,3,3,3-tetrafluoropropene, 2-brom-1 ,3,3,3-tetrafluoropropene, 3-brom-1 , 1 ,3,3-tetrafluoropro- pene, 2-brom-3,3,3-trifluoropropene, E-1-brom-3,3,3-trifluoropropene, 3,3,3-trifluoro-2-(trifluoro- methyl)propene, 1 ,1,1-trifluoro-2-butene and / or mixtures thereof.

[0101] Examples of non-halogenated hydrocarbon blowing agents are acyclic pentane isomers and / or cyclopentane, especially cyclopentane. Preference is given to using acyclic pentane isomers and / or cyclopentane. Preference is given to cyclopentane and mixtures of isopentane with cyclopentane having a content of at least 70 wt.-% of cyclopentane, and particular preference is given to using cyclopentane having a purity of at least 90 wt.-%, especially of at least 95 wt.-%.

[0102] Preferably, the physical blowing agent is a nonfluorinated alkene. Particularly preferred, the physical blowing agent is selected from the group consisting of Z-1,1 ,1 ,4,4,4-hexafluoro-2-bu- tene, E-1,1 ,1 ,4,4,4-hexafluoro-2-butene, 1-chloro-3,3,3-trifluoropropene and 1-chloro-2, 3,3,3- tetrafluoropropene.

[0103] In a preferred embodiment, the amount of the physical blowing agent is in the range of >0 to 35 wt.-%, more preferred from 1 to 10 wt.-% based on the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof. Preferably, the total amount of the at least one blowing agent (d) is 0-20 wt.-%, more preferred 0.5-17 wt.-%, even more preferred 0.7-15 wt.-%, based on the amount of the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof. Preferably, the blowing agent is used in an amount that the free rise density of the resulting foam is in the range of 60 to 200 g / l.

[0104] Catalyst (e)

[0105] As catalysts, it is possible to use all compounds which accelerate the isocyanate-water reaction or the isocyanate-polyol reaction. Such compounds are known and are described, for example, in " Polyurethane Handbook”, Carl Hanser Publishers, 2nd edition 1993, chapter 3.4.1. These include amine-based catalysts and catalysts based on organic metal compounds. As catalysts based on organic metal compounds, it is possible to use, for example, organic tin compounds such as tin(ll) salts of organic carboxylic acids, e.g. tin(ll) acetate, tin(ll) octoate, tin(ll) ethylhexanoate and tin(ll) laurate, and the dial kyltin(IV) salts of organic carboxylic acids, e.g. dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate, and also bismuth carboxylates such as bismuth(lll) neodecanoate, bismuth 2-ethylhexanoate and bismuth octanoate or alkali metal salts of carboxylic acids, e.g. potassium acetate or potassium formate.

[0106] Preference is given to using at least one tertiary amine as catalyst. These tertiary amines may also bear groups which are reactive toward isocyanate, e.g. OH, NH or NH2 groups. Some of the most frequently used catalysts are bis[2-(N,N-dimethylamino)ethyl]ether, N , N , N , N , N-pentamethyldiethylenetriamine, N , N , N-triethylaminoethoxyethanol, dimethylcyclohexylamine, dimethylbenzylamine, triethylamine, triethylenediamine, pentamethyldipropylenetriamine, dimethylethanolamine, N-methylimidazole, N-ethylimidazole, tetramethylhexamethylenediamine, tris(dimethylaminopropyl)hexahydrotriazine, 2,2- bis(hydroxymethyl)butyric acid, N,N-dimethylcyclohexylamine, dimethylaminopropylamine, N- ethylmorpholine, diazabicycloundecene and diazabicyclononene. Preference is given to using mixtures comprising at least two different tertiary amines as catalysts. Preferably, the at least one catalyst is selected from the group consisting of bis[2-(N,N-dimethylamino)ethyl]ether and triethylenediamine, N,N,N,N,N-pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine and dimethylbenzylamine.

[0107] Based on the total weight of all components that are mixed with the at least one di- or polyisocyanate or mixtures thereof, the amount of catalyst is preferably in the range of 0-5 wt.-%, more preferred in the range of 0.3-4.5 wt.-% even more preferred in the range of 0.5-4 wt.-%, based on the amount of the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof.

[0108] Foam stabilizer (f)

[0109] Foam stabilizers are added to stabilize the polyurethane foam. Foam stabilizers are materials which promote formation of a regular cell structure during foaming and are also called surfactants hereinafter. Examples are silicone-comprising foam stabilizers, also called silicon surfactants, such as siloxaneoxalkylene copolymers and other organopolysiloxanes. Further examples include alkoxylation products of fatty alcohols, oxo alcohols, fatty amines, alkylphenols, dialkylphenols, alkylcresoles, alkylresorcinol, naphthol, alkylnaphthol, naphthylamine, aniline, alkylaniline, toluidine, bisphenol A, alkylated bisphenol A, polyvinyl alcohol and also alkoxylation products of condensation products of formaldehyde and alkylphenols, formaldehyde and dialkylphenols, formaldehyde and alkylcresoles, formaldehyde and alkylresorcinol, formaldehyde and aniline, formaldehyde and toluidine, formaldehyde and naphthol, formaldehyde and alkylnaphthol and also formaldehyde and bisphenol A or mixtures of two or more of these foam stabilizers.

[0110] Based on the total weight of all components that are mixed with the at least one di- or polyisocyanate or mixtures thereof, the amount of foam stabilizer is preferably in the range of 0-5 wt.-%, more preferred in the range of 0.5-4.5wt.-% even more preferred in the range of 0.8-4 wt.-%, based on the amount of the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof.

[0111] Further auxiliaries and / or additives

[0112] In a preferred embodiment, the components that are mixed with the at least one di- or polyisocyanate or mixtures thereof may comprise the foam stabilizer (f) as well as other components such as additives and auxiliaries.

[0113] Further auxiliaries and / or additives can optionally be added to the polyurethane foam reaction mixture. Mention may be made of, for example, surface-active substances, antioxidants, chain extenders, cross linkers, cell regulators, fillers, dyes, pigments, flame retardants, hydrolysis inhibitors, fungistatic and bacteriostatic substances. Chain extenders and cross linkers have usually a molecular weight between 60 g / mol to 300 g / mol. Bifunctional chain extenders and the trifunctional and higher-functional cross linkers or, if appropriate, mixtures thereof might be added. Chain extenders and / or cross linkers used are preferably alkanol amines and in particular diols and / or triols having molecular weights preferably between 60 g / mol to 300 g / mol.

[0114] Optionally flame retardants might be used as additives for the polyurethane foam. As flame retardants, it is generally possible to use the flame retardants known from the prior art.

[0115] More detailed information regarding the starting materials, blowing agents, catalysts and auxiliaries and / or additives used to carry out the process according to the invention can be found, for example, in the “Polyurethane Handbook”, Carl Hanser Publishers, 2nd edition 1993.

[0116] In a preferred embodiment, the polyols P), the 4,4-methylenebis(2,6-diethyleneaniline) c), the at least one blowing agent d), the at least one catalyst e) and optionally the at least one foam stabilizer f) as well as additives and / or auxiliaries, if present, are mixed together to form a polyol component. The polyol component is one aspect of the present invention. The polyol component is then reacted with the di- or polyisocyanate or mixtures thereof and, if appropriate, optionally blowing agents. Such a two-component process has proven to be particularly advantageous.

[0117] When producing the foams by the process according to the invention, the polyisocyanate and the isocyanate reactive compounds are preferably reacted at an isocyanate index of 80-140, more preferred 90-130, even more preferred 100-120.

[0118] The reaction mixture is preferably prepared by mechanically mixing the components, preferably in a high-pressure mixing head. Preferably, the mixing head operates in an automated fashion.

[0119] In step II, a layered structure comprising the object and the substrate is formed, wherein the polyurethane foam reaction mixture forms an intermediate layer between the object and the substrate. The object may be attached on the substrate using the polyurethane foam layer as an adhesive.

[0120] The polyurethane foam reaction mixture may be applied to the substrate, to the object or to both the substrate and to the object prior to contacting of the object and the substrate. Preferably, the polyurethane foam reaction mixture is applied to the substrate or to the object. More preferred, the polyurethane foam reaction mixture is applied to the object. The polyurethane foam reaction mixture is preferably applied by pouring. In a preferred embodiment, the polyurethane foam reaction mixture is applied using a pouring mixing head. The advantages of pouring instead of spraying include the avoidance of workspace pollution and a less complicated production process because the precautions that are necessary when spraying are not needed. In a preferred embodiment, the application of the polyurethane foam reaction mixture is automated. During the application, the object or the substrate to which the polyurethane foam reaction mixture is applied may be placed on a conveyor belt, held by a robotic arm or be positioned on another type of device that facilitates an automated process. Preferably, the object or the substrate to which the polyurethane foam reaction mixture is applied is held by a robotic arm.

[0121] After the polyurethane foam reaction mixture has been applied, the object or the substrate to which it was applied can be rotated or otherwise moved already after a short waiting time. The rotating or otherwise moving of the object may be done by a robotic arm or another type of device that facilitates an automated process. The object or the substrate to which the polyurethane foam reaction mixture is applied can preferably be rotated or otherwise moved after 10 seconds after the application, more preferred after 7 seconds after the application, particularly preferred after 5 seconds after the application, without the polyurethane foam reaction mixture dripping from the surface to which it was applied. The ability to rotate or otherwise move the object or the substrate to which the polyurethane foam reaction mixture was applied already after a short time after the application enables the automatization of the process and ensures that the waiting time in step II is short enough to facilitate an efficient production process.

[0122] After the application of the polyurethane foam reaction mixture to the object, to the substrate or to both the object and the substrate, a layered structure comprising the object and the substrate is formed so that the polyurethane foam reaction mixture forms an intermediate layer between the object and the substrate. The forming of the layered structure with the polyurethane foam reaction mixture as an intermediate layer is done before the polyurethane foam reaction mixture has hardened.

[0123] The forming of the layered structure is preferably an automated process step. The forming of the layered structure may be performed by a robotic arm or another type of device that facilitates an automated process. For the forming of the layered structure in step II, either the substrate or the object can be placed in a mold. Alternatively, the forming of the layered structure can take place so that neither the substrate nor the object are placed in a mold. Preferably, neither the object nor the substrate is placed in a mold during step II. The forming of the layered structure is performed so that enough space for the polyurethane foam reaction mixture is left between the object and the substrate. In order to achieve this, the substrate and the object may be held at a defined distance from each other, or a spacer may be inserted between the substrate and the object to maintain a defined distance between them. Especially in an automated process, the substrate and the object can be held at a defined distance from each other without using a spacer, if the distance between the substrate and the object can be kept constant reliably. This can be achieved by using a robotic arm to hold and move the object or the substrate, for example. However, an automated process may also utilize spacers between the object and the substrate.

[0124] Regardless of whether a spacer is utilized or not, the substrate and the object are held at a certain distance from another for a certain amount of time before letting go of either the object or the substrate. The distance is chosen so that the polyurethane foam reaction mixture forms an intermediate layer between the object and the substrate and is in contact with both the substrate and the object. The distance is chosen so that the polyurethane foam layer that is formed when the polyurethane foam reaction mixture cures in step III has a thickness which is suitable for the application. For example, the distance between the object and the substrate may be in the range of 2-50 mm, preferably in the range of 3-40 mm, most preferred in the range of 4-30 mm. The final thickness of the cured polyurethane foam layer may be higher than that of the distance at which the substrate and the object are held from another for a certain amount of time. The higher final thickness may be caused by post-expansion of the polyurethane foam, for example. The final thickness of the cured polyurethane foam may be up to 10, 7, or 5 mm higher than that of the distance at which the substrate and the object are held from another for a certain amount of time, for example. Also other thickness differences are possible. The difference depends on the application including the design of the object and the substrate as well as the production conditions.

[0125] The polyurethane foam reaction mixture and / or the cured polyurethane foam may extend over the edges of the object. For example, the reaction mixture and / or the cured polyurethane foam may ooze out at the edge or at the edges of the object either at all edges or partially.

[0126] The duration of holding the substrate and the object at a certain distance from another before releasing the object and / or the substrate is chosen so that the curing of the polyurethane foam reaction mixture (step III) has proceeded sufficiently so that the structure object formed by the object, the intermediate layer and the substrate is stable. Stable means that the object and the substrate are attached together firmly enough for the layered structure to stay intact when it is moved or processed further. Preferably, the duration of holding the substrate and the object at a certain distance from another before releasing either the object or the substrate is at most 100 sec, more preferred at most 70 sec and even more preferred at most 40 sec.

[0127] The layered structure may comprise further components. The further components may be adjacent to the object and the substrate and / or incorporated between the object and the substrate. The further components may be at least partly incorporated within the intermediate layer between the object and the substrate which is formed by the polyurethane foam reaction mixture. The further components may be attached to the object or to the substrate prior to forming of the layered structure comprising the object and the substrate so that they form a pre-assembled unit which is then attached to the substrate or the object that is not part of the pre-assembled unit. They may also be incorporated between the object and the substrate in the same process step in which the layered structure comprising the object and the substrate is formed or be attached to the object or to the substrate after the layered structure comprising the object and the substrate with the polyurethane foam reaction mixture as an intermediate layer between the object and the substrate is formed.

[0128] In a preferred embodiment, the layered structure comprises a cooling component. The cooling component such as a condenser may be incorporated between the object and the substrate. Preferably, the object is a vacuum insulation panel, the substrate is an outer wall of a cooling device, a wall of an inner container of a cooling device, an outer wall of a door of a cooling device or the inliner or a door of a cooling device, and a cooling component such as a condenser is incorporated between the object and the substrate.

[0129] Preferably, the layered structure comprises a thermal insulation layer. Preferably, the layered structure comprises a thermal insulation layer and the object is a vacuum insulation panel and the substrate is the inside of an outer wall of a cooling device, the outside of a wall of an inner container of a cooling device, or the inside of an outer wall of a door of a cooling device. The layered structure that comprises a thermal insulation layer may additionally comprise a cooling component. The thermal insulation layer may be a polyurethane foam. Suitable polyurethane foams are described in EP3990512 and EP3856815, for example.

[0130] In step III, the polyurethane foam reaction mixture is cured to form a polyurethane foam layer.

[0131] The polyurethane foam reaction mixture preferably has a cream time in the range of 0-10 s at 30 °C, more preferred in the range of 0-7 s at 30 °C, even more preferred in the range of 0-5 s at 30 °C. Preferably, the polyurethane foam is a rigid foam. The polyurethane foam preferably has a free rise density in the range of 60-200 g / l, more preferred in the range of 60-180 g / l, particularly preferred in the range of 60-160 g / l.

[0132] The polyurethane foam preferably has a gel time in the range of 10-35 s at 30 °C, more preferred in the range of 12-27 s at 32 °C, even more preferred in the range of 15-30 s at 30 °C.

[0133] Preferably, the process according to the invention further comprises step IV, in which the object or the substrate is released, as well as step V, in which the process is started again. In step V, a new object and / or a new substrate may be provided in order to form a second or a further layered structure. In this way, a series of layered structures may be prepared.

[0134] A further aspect of the invention is a layered structure comprising an object, a polyurethane foam layer, and a substrate, wherein the layered structure is producible by the process according to the invention.

[0135] A further aspect of the invention is the use of the layered structure prepared according to the process according to the invention or of the layered structure according to the invention for the insulation of a refrigerator.

[0136] The process according to the invention allows for an efficient attaching of objects on substrates. It is suitable for use in an automated process. The polyurethane foam reaction mixture which is used as an adhesive does not drip after application even if the object or the substrate to which it was applied is rotated or otherwise moved. This ensures that the object or the substrate can be moved freely after applying the polyurethane foam reaction mixture. Further, the curing time of the polyurethane foam reaction mixture is short enough for an automated process but long enough to ensure that the polyurethane foam does not harden too early. No long waiting times after the application of the reaction mixture are required, which is crucial for an automated, industrial process. Moreover, the object or the substrate can be handled with a robotic arm or other automated systems and can be moved and rotated freely by them. It is not necessary to place the object, the substrate or both in a mold for the attachment step, which reduces the complexity of the attachment step as well as the number of parts needed in it. The process according to the invention allows for the attachment of objects and substrates even if the object, the substrate, or both are not planar. For example, the object, the substrate, or both can have an embossed surface structure and / or comprise protrusions and / or dimples such as ribbed structures or honeycomb structures. The process avoids workspace pollution that would occur if the polyurethane foam reaction mixture was applied by spraying. Experimental part

[0137] Measurement methods:

[0138] Measurement of hydroxyl number:

[0139] Hydroxyl numbers are determined according to DIN 53240 (1971-12).

[0140] Cup density:

[0141] The cup density was determined by measuring the foam density in the core in accordance with DIN EN ISO 845.

[0142] Cream time:

[0143] The time from the commencement of mixing of the reaction mixture to the start of foam expansion.

[0144] Gel time (setting time / fiber time):

[0145] Time from the commencement of mixing of the reaction mixture up to the time until it is possible to draw threads in contact with the foam (for example with a wooden rod). This point thus represents the transition from a liquid to a solid state.

[0146] Dripping behavior:

[0147] Thixotropy, and associated dripping behavior, was tested on a VIP panel. For this purpose, 150g reaction mixture is foamed onto a VIP panel and turned over after 10 seconds. If the mixture drips off, the formulation was not suitable. If the reaction mixture does not drip off, the test was repeated again at 5 seconds.

[0148] Raw materials i) Polyols

[0149] Polyol 1 : Polyether polyol based on sucrose, glycerol and propylene oxide (PO) having an OH number of 490 mg KOH / g; functionality: 4.34

[0150] Polyol 2: Polyether polyol based on glycerol and PO having an OH number of 400 mg KOH / g; functionality: 2.99*

[0151] Polyol 3: Polyether polyol based on propylene glycol and PO having an OH number of 55 mg KOH / g; functionality: 1.93** Polyol 4: Polyether polyol based on ethylenediamine and PO having an OH number of 750 mg KOH / g; functionality: 4.0

[0152] * The functionality of polyol 2 is <3 due to the presence of small amounts of water that were added via addition of the catalyst to the starter glycerol.

[0153] ** The functionality of polyol 3 is <2 due to the presence of small amounts of water that were added via addition of the catalyst to the starter propylene glycol. ii) Catalysts

[0154] Catalyst 1: Lupragen N 201 (BASF)

[0155] Catalyst 2: Lupragen N 206 (BASF)

[0156] Catalyst 3: bis(2-dimethylaminoethyl)ether iii) Additive

[0157] Surfactant: Tegostab® B 84204 from Evonik (stabilizer)

[0158] Crosslinker 1 : Diethyltoluoldiamine

[0159] Crosslinker 2: 4,4-methylenebis(2,6-diethyleneanilin)

[0160] Crosslinker 2: O,O’-bis(2-aminopropyl)polypropylenglycol iv) Isocyanate

[0161] Isocyanate 1: Polymer MDI having a viscosity of 210 mPas at 25 °C

[0162] Components i) to iii) were mixed to give a polyol component and reacted with the isocyanate iv). The amounts of the feedstocks used can be found in tables 1 and 2. CE denotes comparative examples, E denotes inventive examples. E3 was a machine run and E1-E2, E4-E6 as well as all comparative examples were laboratory examples.

[0163] In E3, mixing was affected in a mixing head. Machine setting (Hennecke TopLine HK 650 / 650 / 45 P): 150g / s discharge capacity, 150bar pressure at the mixing head (MT18-4 company Hennecke), component temperature 30°C.

[0164] Metal sheets: 500x500x1 mm

[0165] Vacuum panels: 500x500x40 mm (core material open-cell PU foam)

[0166] Spacer: 46mm

[0167] Layer thickness PU foam (pressed): 5mm Table 1

[0168] Table 2

[0169] The inventive examples show no dripping, whereas in the comparative examples, the polyurethane foam reaction mixture drips from the substrate.

[0170] Robot-assisted application test 1

[0171] Testing of the optimal application method and quantity of the reaction mixture by means of 6- axis robots (ABB) and mold carriers (tool carriers of the company FRIMO).

[0172] Machine setting (Elastogran Maschinenbau 30 / 80 IQ): 100g / s discharge rate, 120bar pressure at the mixing head (MT18 company Hennecke), component temperature 30°C.

[0173] Metal sheets: 1000x640x1 mm,

[0174] 1600x640x1 mm

[0175] Vacuum panels: 700x385x15 mm (core material silica),

[0176] 1450x465x15 mm (core material silica)

[0177] Spacer: 22mm

[0178] Layer thickness Pll foam (pressed): 6mm

[0179] Polyurethane foam reaction mixture: prepared according to inventive example E3 The vacuum panels were first wrapped with PE film in order to be able to separate them from the Pll foam again. By means of a tool carrier from FRIMO, the vacuum panels were attached to the metal sheets. For this purpose, the panels were adhered to the upper carrier with vacuum cups and the polyurethane reaction mixture was applied to the metal sheets on the lower carrier. The spacers between the upper and the lower carrier of 22mm thickness were used to obtain a uniform Pll layer thickness of 6mm. After a demolding time of 45 seconds, the carrier was opened, the VIP panel removed and the result examined. The travel paths of the robot as well as the speed and the associated application quantity were optimized until the VIP panel is bonded over the surface and some material swells out on the sides. Subsequently, the VIP panels were bonded without the PE film in order to confirm the result again. As a result, the VIP panels were attached evenly and firmly to the metal sheets.

[0180] Robot-assisted application test 2

[0181] Testing of foam behavior when using only a 6-axis robot (ABB) without mold carrier

[0182] Machine setting (Cannon A-100), 50 g / s discharge capacity, 140 bar pressure at the mixing head (FPL 10 company Cannon), component temperature 30°C.

[0183] Metal sheets: 1100x630x0, 5mm

[0184] Vacuum panels: 700x385x15 mm (core material silica)

[0185] 965x580x40 mm (core material open-cell Pll foam)

[0186] Layer thickness PU foam (pressed): 5mm Polyurethane foam reaction mixture: prepared according to inventive example E3

[0187] The VIP panel was picked up by means of a vacuum holding device adapted to the robot, moved under the mixing head and the reaction mixture is foamed in the application method to be tested (travel paths) and speed. The amount of reaction mixture was chosen so that the polyurethane foam partly oozed out at the sides of the panel. The panel was then turned upside down and held at the appropriate distance (5mm) over the sheet with the foam side facing down so that the foam could expand there. After 45 seconds, the panel and the sheet were bonded together. In order to first determine the optimal travel routes and speeds, the panel was wrapped in PE film. After the foaming process, the panel could be removed and the distribution inspected. Once everything was optimized, the panel was firmly bonded without the PE film and then the adhesion was checked. As a result, the VIP panels were attached evenly and firmly to the metal sheets.

Claims

Claims1 . A process for forming a layered structure comprising an object, a polyurethane foam layer, and a substrate, the process comprising the stepsI. preparing a polyurethane foam reaction mixture by mixing at least a. at least one di- or polyisocyanate or mixtures thereof; b. polyols P) comprising b1) at least one polyether polyol P1) having a functionality in the range of 3.5-8 and an OH number in the range of 350 to 800 mg KOH / g, wherein at least one starter compound of the polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms; b2) at least one polyol P2) having a functionality in the range of 2.5-3.5 and an OH number in the range of 300-450 mg KOH / g; and b3) at least one polyol P3) having a functionality in the range of 1.8-4.1 and an OH number in the range of 40-260 mg KOH / g; c. 4,4-methylenebis(2,6-diethylaniline); d. at least one blowing agent; e. at least one catalyst; and optionally f. at least one foam stabilizer,II. forming a layered structure comprising the object and the substrate, wherein the polyurethane reaction mixture forms an intermediate layer between the object and the subject; andIII. curing the polyurethane foam reaction mixture to form a polyurethane foam layer.

2. The process according to claim 1 , wherein the polyols P) comprise at least one polyol P4) selected from reaction products of ethylenediamine, toluenediamine and / or dimethylaminopropylamine with alkylene oxides and having an OH number in the range of 600-800 mg KOH / g.

3. The process according to claim 1 or 2, wherein the at least one di- or polyisocyanate is selected from the group consisting of tolylene diisocyanate, methylene diphenyl diisocyanate, mixtures of methylene diphenyl diisocyanate and polyphenylpolymethylene polyisocyanates and / or related isocyanate prepolymers.

4. The process according to any of claims 1 to 3, wherein the at least one blowing agent comprises water.

5. The process according to any of claims 1 to 4, wherein the at least one blowing agent comprises water and a physical blowing agent.

6. The process according to any of claims 1 to 5, wherein the amount of the at least one polyether polyol P1) is 20-60 wt.-%, the amount of the at least one polyol P2) is 20-60 wt.-%, and the amount of the at least one polyol P3) is 5-20 wt.-%, and wherein all amounts are based on the total weight of the polyols P).

7. The process according to any of claims 1 to 6, wherein neither the object nor the substrate is placed in a mold during step II.

8. The process according to any of claims 1 to 7, wherein the object is a panel, a board, a mat, or a sheet.

9. The process according to any of claims 1 to 8, wherein the object is a vacuum insulation panel, a thermal insulation board, a sound insulation sheet, or a honeycomb sheet.

10. The process according to any of claims 1 to 9, wherein the substrate is an outer wall of a cooling device, a wall of an inner container of a cooling device, an outer wall of a door of a cooling device, an inner wall of a door of a cooling device, an inliner of a door of a cooling device, an outer wall of a dishwasher, or a wall of an inner container of a dishwasher.11 . The process according to any of claims 1 to 10, wherein the object is a vacuum insulation panel and the substrate is an outer wall of a cooling device, a wall of an inner container of a cooling device, an inner wall of a door of a cooling device, an outer wall of a door of a cooling device, or an inliner of a door of a cooling device.

12. The process according to any of claims 1 to 11 , wherein a cooling component such as a condenser is incorporated between the object and the substrate.

13. The process according to any of claims 1 to 12, wherein the density of the polyurethane foam layer is in the range of 60-200 g / l.

14. The process according to any of claims 1 to 13, wherein the process is an automated process.

15. A layered structure comprising an object, a polyurethane foam layer, and a substrate, wherein the layered structure is producible by the process according to any of claims 1 to 14.

16. Use of the layered structure prepared according to the process according to any of claims 1 to 14 or of the layered structure of claim 15 for the insulation of a cooling device.

17. A polyol component comprising i. polyols P) comprising11) 20-60 wt.-% of at least one polyether polyol P1) having a functionality in the range of 3.5-8 and an OH number in the range of 350 to 800 mg KOH / g, wherein at least one starter compound of the polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide, and / or a sugar alcohol and has at least 4 active hydrogen atoms;12) 20-60 wt.-% at least one polyol P2) having a functionality in the range of 2.5- 3.5 and an OH number in the range of 300-450 mg KOH / g;13) 5-20 wt.-% at least one polyol P3) having a functionality in the range of 1 .8- 4.1 and an OH number in the range of 40-260 mg KOH / g; and wherein the amounts of the polyols P1) to P3) are based on the total weight of the polyols P); ii. 0.2-5 wt.-% 4,4-methylenebis(2,6-diethylaniline); iii. 0-15 wt.-% at least one blowing agent; iv. 0-5 wt.-% at least one catalyst; and optionally v. 0-5 wt.-% at least one foam stabilizer; wherein the amounts of the components ii to v are based on the total weight of the polyol component.

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