Method for producing layered system comprising polyurethane foam layer

Abstract

The invention relates to a method for producing a layered structure comprising an object, a polyurethane foam layer and a substrate, to a layered structure which can be produced by the method, to the use of the layered structure for insulating a cooling device, and to a polyol component which can be used in the method.

Description

Method for producing a layered system including a polyurethane foam layer

[0001] The present invention relates to a method for producing a layered structure comprising an object, a polyurethane foam layer and a substrate, a layered structure that can be produced by the method, the use of the layered structure for insulating a cooling device, and a polyol component that can be used in the method.

[0002] In automated production methods, it is often necessary to attach objects or layers together. Examples of such objects are vacuum-insulated panels in cooling devices such as refrigerators and / or freezers, and bitumen sound insulation sheets in dishwashers. Using double-sided tape is cumbersome and unsuitable for automated methods. Furthermore, it is only suitable for attaching flat objects or layers together; it is not a good solution for protrusions, depressions, or other three-dimensional structures. This is, for example, the case in cooling devices where the wall to be attached to the vacuum-insulated panel may have a ribbed structure. Liquid adhesives are an option to overcome the disadvantages of double-sided tape. However, they typically cure too slowly, and if the surface to which they are applied is rotated immediately after application, they drip off. This results in long cycle times in production, reducing productivity. On the other hand, if the adhesive hardens too quickly, it cannot properly attach objects or layers together, and the quality of the produced items deteriorates. Additionally, in applications such as cooling devices, adhesives that contribute to the insulation of the device are desirable.

[0003] Attaching a vacuum-insulated panel to a cooling device is known from EP 2705315 B2. This patent describes a cooling device comprising a vacuum-insulated panel, which is attached to a boundary wall using a foamable liquid adhesive. The cooling component can be integrated into the foamable liquid adhesive between the boundary wall and the vacuum-insulated panel.

[0004] The object of this invention is to develop an adhesive suitable for use in automated methods for attaching objects to substrates. The processing time should be sufficiently long to allow for the attachment step. Simultaneously, the adhesive should not drip after application, even when the object or substrate to which the adhesive has been applied is rotated or otherwise moved without a long waiting period. Adhesion should be good even under mechanical stresses such as vibration. The attachment process should not result in workplace contamination similar to that caused by spraying. Furthermore, it should be possible to attach objects to substrates without placing one or both of them into a mold. If the object, substrate, or both have an embossed surface structure and / or include protrusions and / or pits, it should be possible to attach the object to the substrate. In this case, the adhesive should fill the structure such that the object and substrate are also attached in the protrusions, in the pits, and between the protrusions, pits, and / or both. Examples of such structures are ribbed structures and honeycomb structures. The components of the adhesive should be easily stored and should not contain hazardous substances. Furthermore, the adhesive should contribute to thermal insulation if intended for use in the application.

[0005] This objective is surprisingly achieved through a method for forming a layered structure comprising an object, a polyurethane foam layer, and a substrate, the method comprising the following steps:

[0006] I. A polyurethane foam reaction mixture is prepared by mixing at least the following:

[0007] a. At least one diisocyanate or polyisocyanate or a mixture thereof;

[0008] b. Polyol P), which includes

[0009] b1) At least one polyether polyol P1), the polyether polyol P1) having a functionality in the range of 3.5-8 and an OH value in the range of 350 mg KOH / g to 800 mg KOH / g, wherein at least one initiator compound of the polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide and / or sugar alcohol and has at least 4 active hydrogen atoms;

[0010] b2) At least one polyol P2), wherein the polyol P2) has a functionality in the range of 2.5-3.5 and an OH value in the range of 300 mg KOH / g-450 mg KOH / g; and

[0011] b3) At least one polyol P3), wherein the polyol P3) has a functionality in the range of 1.8-4.1 and an OH value in the range of 40 mg KOH / g-260 mg KOH / g; and

[0012] c.4,4-Methylenebis(2,6-diethylaniline);

[0013] d. At least one foaming agent;

[0014] e. at least one catalyst; and optionally

[0015] 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. Allow the reaction mixture to cure to form a polyurethane foam layer.

[0018] This objective is also achieved through a layered structure comprising an object, a polyurethane foam layer, and a substrate, wherein the layered structure can be produced by the method described above, and through the use of a layered structure prepared according to the method described above, or a layered structure that can be produced by the method described above for insulating a cooling device. Furthermore, this objective is achieved through a polyol component that can be used in the method described above.

[0019] The method according to the invention enables effective attachment of an object to a substrate. It is suitable for automated processes. The object and substrate are attached via a polyurethane reaction mixture that acts as an adhesive. The polyurethane reaction mixture can be applied to the object and / or substrate by pouring rather than spraying. Therefore, this method avoids workplace contamination that would occur with the application of the polyurethane foam reaction mixture by spraying. Even if the object or substrate to which the polyurethane foam reaction mixture has been applied is rotated or otherwise moved, the polyurethane foam reaction mixture will not drip after application. This ensures that the object or substrate can be moved freely after the application of the polyurethane foam reaction mixture. Furthermore, the curing time of the polyurethane foam reaction mixture is short enough for automated processes, but long enough to ensure that the polyurethane foam does not harden prematurely. The absence of a long waiting period after application of the reaction mixture is crucial for automated industrial processes. Moreover, the object or substrate can be handled by robotic arms or other automated systems and can be moved and rotated freely by them. There is no need to place the object, substrate, or both in a mold for the attachment step, which reduces the complexity of the attachment step and the number of parts required therein. The method according to the invention enables attachment of an object and substrate even if the object, substrate, or both do not have flat surfaces. For example, an object, substrate, or both may have an embossed surface structure and / or include protrusions and / or pits.

[0020] The invention is described in more detail below.

[0021] One aspect of the present invention is a method for forming a layered structure comprising an object, a polyurethane foam layer, and a substrate, the method comprising the following steps:

[0022] I. A polyurethane foam reaction mixture is prepared by mixing at least the following:

[0023] a. At least one diisocyanate or polyisocyanate or a mixture thereof;

[0024] b. Polyol P), which includes

[0025] b1) At least one polyether polyol P1), the polyether polyol P1) having a functionality in the range of 3.5-8 and an OH value in the range of 350 mg KOH / g to 800 mg KOH / g, wherein at least one initiator compound of the polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide and / or sugar alcohol and has at least 4 active hydrogen atoms;

[0026] b2) At least one polyol P2), wherein the polyol P2) has a functionality in the range of 2.5-3.5 and an OH value in the range of 300 mg KOH / g-450 mg KOH / g; and

[0027] b3) At least one polyol P3), wherein the polyol P3) has a functionality in the range of 1.8-4.1 and an OH value in the range of 40 mg KOH / g-260 mg KOH / g; and

[0028] c.4,4-Methylenebis(2,6-diethylaniline);

[0029] d. At least one foaming agent;

[0030] e. at least one catalyst; and optionally

[0031] f. At least one foam stabilizer,

[0032] 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

[0033] III. Allow the reaction mixture to cure to form a polyurethane foam layer.

[0034] Those skilled in the art will know that the term "polyurethane" includes not only polymers containing urethane groups, but also polymers containing little or no urethane groups, provided that these polymers are derived from bifunctional or polyfunctional isocyanates; see Polyurethane Handbook, 2nd edition, 1993, edited by Guether Oertel and Carl Hanser Verlag Munich, Chapter 2.1.1. Examples are polyether urea, polyisocyanurate, polyurea, and polycarbodiimide. Polymers containing urethane groups are preferred as polyurethanes.

[0035] According to the present invention, the term "polyurethane foam reaction mixture" refers to the polyurethane mixture between the start time of mixing of the reaction components and the detack time of the polyurethane foam material.

[0036] The layered structure according to the present invention includes an object, a polyurethane foam layer, and a substrate.

[0037] The object, substrate, or both may have an embossed surface structure and / or include protrusions and / or pits. Non-exhaustive examples of such structures are ribbed structures and honeycomb structures.

[0038] The object according to the invention is an object to be attached to a substrate. The object can be a panel, sheet, pad, sheet, foil, or textile. Preferably, the object can be a vacuum-insulated panel, heat insulation panel, sound insulation sheet, wood panel, honeycomb sheet (such as paper honeycomb sheet), plastic sheet, plastic plate, metal sheet, metal plate, textile pad, glass pad, mineral wool component (such as mineral wool board), fiber-reinforced composite component, glass fiber component, foil, textile, sheet molding compound (SMC) component, or bulk molding compound (BMC) component. Preferably, the object is a vacuum-insulated panel, heat insulation panel, sound insulation sheet, or honeycomb sheet (such as paper honeycomb sheet).

[0039] Preferably, the object is a vacuum-insulated panel or a sound-insulating sheet. The sound-insulating sheet may be an asphalt sound-insulating sheet. Particularly preferably, the object is a vacuum-insulated panel.

[0040] The substrate according to the invention is a substrate to be attached to an object. The substrate can be a wall, door, top, inside, outside, bottom, or top side. The substrate can be part of a cooling device (such as a refrigerator, freezer, or refrigerator-freezer combination), dishwasher, automobile, tractor, agricultural machinery, campervan, caravan, trailer, or truck trailer. "Part" means the entire substrate or a portion of the aforementioned device. The substrate can be a wall, door, top, inside, outside, bottom, or top side of a cooling device (such as a refrigerator, freezer, or refrigerator-freezer combination), dishwasher, automobile, tractor, agricultural machinery, campervan, caravan, trailer, or truck trailer.

[0041] Preferably, the substrate is the outer wall of the cooling device, the wall of the inner container of the cooling device, the outer wall of the door of the cooling device, the inner wall of the door of the cooling device, the inner lining of the door of the cooling device, the outer wall of the dishwasher, or the wall of the inner container of the dishwasher.

[0042] Preferably, the substrate is the outer wall of the cooling device, the wall of the inner container of the cooling device, the outer wall of the door of the cooling device, the inner wall of the door of the cooling device, or the inner lining of the door of the cooling device.

[0043] Preferably, the object is a vacuum-insulated panel, and the substrate is the outer wall of the cooling device, the wall of the inner container of the cooling device, the inner wall of the door of the cooling device, the outer wall of the door of the cooling device, or the inner lining of the door of the cooling device. The cooling device may be a refrigerator, a freezer, and / or a refrigerator-freezer combination.

[0044] Preferably, the object is a soundproof sheet, and the substrate is the inner side of the outer wall of the dishwasher or the outer side of the wall of the inner container of the dishwasher.

[0045] Preferably, one or more steps of the method according to the invention can be automated. The method according to the invention is preferably an automated method.

[0046] In step I of this invention, a polyurethane foam reaction mixture is prepared.

[0047] The polyurethane foam reaction mixture is prepared by mixing at least the following: at least one diisocyanate or polyisocyanate or a mixture thereof; a polyol P), which includes the following polyols P1), P2), and P3; 4,4-methylenebis(2,6-diethylaniline); at least one blowing agent; at least one catalyst; and optionally at least one foam stabilizer. In a preferred embodiment, additives and / or auxiliaries may also be mixed with other components of the foam reaction mixture.

[0048] Diisocyanates or polyisocyanates (a)

[0049] The diisocyanate or polyisocyanate used, or mixtures thereof (a), may comprise any aliphatic, alicyclic, and aromatic bifunctional or polyfunctional isocyanate known in the art, and any desired mixtures of these substances. The diisocyanate or polyisocyanate may optionally be modified.

[0050] Specific examples include alkylene diisocyanates having 4 to 12 carbon atoms in the alkylene group, 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; alicyclic diisocyanates, such as cyclohexane 1,3-diisocyanate and cyclohexane 1,4-diisocyanate and any mixtures of these isomers, 1-isocyano-3,3,5-trimethyl-5-isocyanomethylcyclohexane (IPDI), hexahydrotoluene 2,4-diisocyanate and hexahydrotoluene 2,6-diisocyanate and corresponding mixtures of isomers, dicyclohexylmethane 4,4'-diisocyanate, dicyclohexylmethane 2,2'-diisocyanate, and dicyclohexylmethane 2,4'-diisocyanate. Isocyanates and mixtures of their corresponding isomers, and preferably aromatic diisocyanates and polyisocyanates, such as, for example, toluene 2,4-diisocyanate and toluene 2,6-diisocyanate and mixtures of their corresponding isomers, methylene diphenyl 4,4'-diisocyanate, methylene diphenyl 2,4'-diisocyanate and methylene diphenyl 2,2'-diisocyanate and mixtures of their corresponding isomers, mixtures of methylene diphenyl 4,4'-diisocyanate and methylene diphenyl 2,4'-diisocyanate, polyphenyl polymethylene polyisocyanate, mixtures of methylene diphenyl 4,4'-diisocyanate, methylene diphenyl 2,4'-diisocyanate and methylene diphenyl 2,2'-diisocyanate with polyphenyl polymethylene polyisocyanate (polymeric MDI or PMDI), and mixtures of polymeric MDI and toluene diisocyanate. Diisocyanates and polyisocyanates may be used alone or in mixtures thereof.

[0051] Modified polyfunctional isocyanates are also frequently used, which are products obtained through the chemical reaction of organic polyisocyanates. Examples that may be mentioned are polyisocyanates containing ester, urea, biuret, urethane, carbodiimide, isocyanurate, diurea, carbamate and / or carbamate groups.

[0052] Polyisocyanates can also be used in the form of prepolymers. These polyisocyanate prepolymers are obtained by reacting the aforementioned polyisocyanate with a compound having at least two groups that are reactive to isocyanates to form a prepolymer.

[0053] Furthermore, the prepolymer and mixtures of the aforementioned isocyanate and prepolymer can be used as isocyanates (a). These polyisocyanate prepolymers can be obtained by reacting an excess of the aforementioned polyisocyanate with a compound having at least two groups reactive to isocyanates to obtain the prepolymer. The reaction can be carried out at a temperature, for example, from 30°C to 100°C, preferably from about 45°C to 60°C. The prepolymer typically has an NCO content in the range of 14 wt.-% to 32 wt.-% and preferably from 25 wt.-% to 30 wt.-%

[0054] Compounds having at least two isocyanate-reactive groups are known and described, for example, in “Polyurethane Handbook”, Carl Hanser Publishers, 2nd edition, 1993, Chapter 3.1. For example, polyether polyols and polyester polyols can be used as compounds having at least two isocyanate-reactive groups in the preparation of prepolymers.

[0055] Preferably, the compound having at least two groups reactive to isocyanates is a polyether polyol and / or polyester polyol containing an OH group derived from, for example, propylene oxide. The polyether polyol and / or polyester polyol preferably has a functionality in the range of 2 to 4, particularly preferably in the range of 2 to 3. Particularly preferably, the compound having at least two groups reactive to isocyanates is a polyester polyol.

[0056] Preferred diisocyanates or polyisocyanates (a) are toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), mixtures of methylene diphenyl diisocyanate and polyphenyl polymethylene polyisocyanate (polymeric MDI or PMDI) and / or related isocyanate prepolymers. Particularly preferred is that at least one diisocyanate or polyisocyanate is selected from the group consisting of methylene diphenyl diisocyanate and / or polymeric MDI and / or related isocyanate prepolymers.

[0057] Polymerized MDI is a particularly preferred choice.

[0058] Preferred prepolymers are mixtures of polymeric MDI and polyester polyols. Particularly preferred are prepolymers comprising the reaction product of polymeric MDI and polyester polyols containing monomer units derived from dicarboxylic acids, fatty acids, and polyfunctional alcohols.

[0059] In a preferred configuration, the prepolymer comprises 92 wt.-% to 97 wt.-% of the reaction product of polymeric MDI and 3 wt.-% to 8 wt.-% of a polyester polyol containing monomer units derived from dicarboxylic acids, fatty acids and polyfunctional alcohols.

[0060] If an isocyanate prepolymer is used as the isocyanate, the content of the compound having a reactive group to isocyanate is calculated, taking into account the compounds used to prepare the isocyanate prepolymer.

[0061] Polyols P) (b)

[0062] The OH value (hydroxyl value) can be determined using recognized methods. For example, the OH value can be determined according to DIN 53240 (1971-12).

[0063] In the context of this invention, the functionality of polyols, particularly polyols P1), P2), and P3), and other polyols used according to the invention, refers to the number of alkylene oxide reactive hydrogen atoms per mole of the initiator compound or per mole of the initiator compound mixture prior to the alkylene oxide stoichiometric time. In this case, the alkylene oxide stoichiometric time is the start time at which the alkylene oxide component is added to the initiator compound. The calculation takes into account all alkylene oxide reactive hydrogen atoms of the initiator compound present in the initiator mixture.

[0064] In the context of this invention, the functionality F is calculated according to the following formula (I):

[0065] (I)

[0066] Number of moles of initiator i

[0067] Functionality of initiator i

[0068] =Amount of initiator in the initiator mixture

[0069] F = Functionality

[0070] The functionality F of a polyol produced from a mixture of two initiator compounds (m=2) is calculated as follows:

[0071] F = (moles of initiator compound A × functionality of initiator compound A + moles of initiator compound B × functionality of initiator compound B) / (moles of initiator A + moles of initiator B).

[0072] For other initiator compounds, the formula can be modified accordingly. Thus, for example, when using 626.48 mol glycerol (functionality 3), 559.74 mol sucrose (functionality 8), and 67.31 mol dimethylethanolamine (functionality 1), the polyether polyol has a functionality of 5.12.

[0073] 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 an easily available method for determining the functionality of polyols; see M. Ionescu, “Chemistry and Technology of Polyols for Polyurethanes”, 2005, Rapra Technology Limited, pp. 34-39.

[0074] The functionality of polyether polyols P1), P2), and P3), and other polyols as defined above according to the invention, may differ from the functionality after the initial addition of at least one epoxide, i.e., during the reaction of at least one epoxide with the initiator compound, or from the functionality of the reaction products, because byproducts such as ethylene glycol and unsaturated monofunctional components are formed during the reaction. Side reactions are known in the literature. Therefore, the functionality of polyether polyols P1), P2), and P3), and other polyols may also be referred to as the functionality of the initiator compound or mixture of initiator compounds used to prepare the respective polyols.

[0075] In the context of this invention, a polyol is an organic compound containing at least two hydrogen atoms reactive to isocyanates. Examples of polyols are polyether polyols, polyester polyols, polyether ester polyols, polymer polyols, and polycarbonate polyols. Polyols are prepared by alkoxylation of one or more initiator compounds; the reaction of the initiator compound with an epoxide and the preparation of the polyol are known to those skilled in the art. An initiator compound is a compound having active hydrogen atoms. In the reaction with an epoxide, the epoxide is added to the initiator compound, which may be carried out using a catalyst. One or more initiator compounds may participate in the reaction. This reaction is known to those skilled in the art. Initiator compounds are also commonly referred to as initiator molecules, initiating compounds, or initiators.

[0076] In the context of this invention, polyether polyols are organic compounds containing at least ether and OH groups as functional groups. Polyether polyols are reaction products of initiator compounds having at least two reactive hydrogen atoms of an epoxide with an epoxide. Initiator compounds used for polyether polyols include compounds having at least two OH groups and polyamines having at least two NH2 groups. The preparation of polyether polyols is known to those skilled in the art.

[0077] Preferably, one or more compounds having 2 to 4 carbon atoms in the alkylene group are used, also known as C2 to C4 alkylene oxides, such as ethylene oxide, 1,2-epoxypropane, tetrahydrofuran, 1,3-epoxypropane, 1,2-epoxybutane or 2,3-epoxybutane (in each case alone or in mixtures), and particularly preferably ethylene oxide and / or 1,2-epoxypropane as alkylene oxides.

[0078] The polyol P according to the present invention comprises at least one polyether polyol P1), at least one polyol P2), and at least one polyol P3. The polyol P1 preferably further comprises at least one polyol P4.

[0079] Polyether polyol P1)

[0080] At least one initiator compound of the polyether polyol (P1) is a monosaccharide, oligosaccharide, polysaccharide, and / or sugar alcohol and has at least four active hydrogen atoms. Alternatively, other initiator compounds may be used. Possible initiator compounds of the polyol (P1) are monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polyols, mixtures thereof, and alkoxylated products of the above compounds, wherein the monosaccharide, oligosaccharide, polysaccharide, and sugar alcohol all have at least four active hydrogen atoms.

[0081] Preferably, the polyether polyol (P1) is an alkoxylated product of monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polyols, or mixtures thereof, as well as an alkoxylated product of the above compounds with C2 to C4 epoxides, wherein at least one initiator compound is a monosaccharide, oligosaccharide, polysaccharide, and / or sugar alcohol and has at least four active hydrogen atoms. The C2 to C4 epoxides are preferably selected from ethylene oxide and / or propylene oxide and / or mixtures of ethylene oxide and propylene oxide.

[0082] Monosaccharides, oligosaccharides, polysaccharides, sugar alcohols, polyols, and mixtures thereof can be reacted with the aforementioned alkyl oxides to form alkoxylated products. The alkoxylated products are typically prepared using C2 to C4 alkyl oxides, preferably ethylene oxide and / or propylene oxide. Then, in the preparation of the polyether polyol (P1), the alkoxylated product may be reacted again with the alkyl oxide as a starting compound, possibly in the presence of another initiating compound. Using the alkoxylated product as the initiating compound is particularly advantageous when employing another initiating compound that is initially present as a solid or has a high viscosity.

[0083] Preferably, alkoxylated products of monosaccharides, oligosaccharides, polysaccharides, polyols, or mixtures thereof are added during the preparation of polyether alcohol (P1) to reduce viscosity.

[0084] When calculating the functionality of the polyether polyol P1 according to the present invention, the above-mentioned alkoxylated products are correspondingly considered.

[0085] Examples of suitable initiator compounds for polyether polyols (P1) are sugar derivatives such as sucrose, lactose, maltose, glucose, allose, arbutin, gulose, idole, galactose, tarose, fructose, sorbitol, tagatose, mannose, allulose; hexitol derivatives such as sorbitol, mannitol; and other diols or polyols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,2,4-butanetriol, 1,3,5-pentanetriol, erythritol, and pentaerythritol, wherein at least one initiator compound is a monosaccharide, oligosaccharide, polysaccharide, and / or sugar alcohol and has at least four active hydrogen atoms.

[0086] Preferably, the monosaccharides, oligosaccharides, polysaccharides, and / or sugar alcohols having at least four active hydrogen atoms are selected from the group consisting of: sucrose, lactose, maltose, glucose, allose, adroose, gulose, idole, galactose, tarose, fructose, sorbitol, tagatose, mannose, allulose, erythritol, and sorbitol. Sucrose and sorbitol are particularly preferred. Sucrose is especially preferred.

[0087] Preferably, at least one initiator compound of the polyether polyol (P1) is a polyol having 2-3 active hydrogen atoms. More preferably, at least one initiator compound of the polyether polyol (P1) is selected from the group consisting of: ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,2,4-butanetriol, and 1,3,5-pentanetriol. Particularly preferred polyols are diethylene glycol, dipropylene glycol, trimethylolpropane, and glycerol; glycerol is particularly preferred.

[0088] In a preferred embodiment, the initiator compound of the polyether polyol (P1) is selected from sucrose and sorbitol, wherein glycerol serves as a second initiator. A mixture of initiators comprising glycerol and sucrose is particularly preferred.

[0089] In most cases, basic compounds are used as alkoxylation catalysts for the reaction of initiator compounds with alkyl oxides. In industrial processes, these substances are primarily alkali metal hydroxides, such as, for example, sodium hydroxide, cesium hydroxide, or especially potassium hydroxide. Alkali metal alkoxides, such as, for example, sodium methoxide, sodium methoxide, potassium methoxide, or potassium isopropoxide, are known as catalysts. Preparation may also be affected by amine catalysts.

[0090] The amine catalyst is preferably selected from the group consisting of: 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 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 imidazoles.

[0091] The formation of the adduct with the epoxide is preferably carried out at a temperature between 90°C and 150°C and a pressure between 0.1 bar and 8 bar. A post-addition stage typically follows the metering of the epoxide, in which the epoxide is depleted through the reaction. If necessary, a post-reaction stage may then be performed. Typically, distillation under reduced pressure is then preferably carried out to separate the volatile components.

[0092] The functionality of the polyether polyol (P1) is at least 3.5, preferably at least 3.7, more preferably at least 3.9, and even more preferably at least 4.0. The functionality of the polyether polyol (P1) is at most 8.0, preferably at most 7.9, more preferably at most 7.0, and even more preferably 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 preferably in the range of 3.9 to 7.0, and even more preferably in the range of 4.0 to 6.5.

[0093] The OH value of the polyether polyol (P1) is at least 350 mg KOH / g, preferably at least 370 mg KOH / g, more preferably at least 390 mg KOH / g, and even more preferably at least 400 mg KOH / g. The OH value of the polyether polyol (P1) is at most 800 mg KOH / g, preferably at most 650 mg KOH / g, more preferably at most 550 mg KOH / g, and even more preferably at most 510 mg KOH / g. The OH value of the polyether polyol (P1) is in the range of 350 mg KOH / g to 800 mg KOH / g, preferably in the range of 370 mg KOH / g to 650 mg KOH / g, more preferably in the range of 390 mg KOH / g to 550 mg KOH / g, and even more preferably in the range of 400 mg KOH / g to 510 mg KOH / g.

[0094] In a preferred configuration, the polyether polyol (P1) has a functionality in the range of 3.5 to 8.0 and an OH value in the range of 350 mg KOH / g to 800 mg KOH / g; more preferably, a functionality in the range of 3.7 to 7.9 and an OH value in the range of 370 mg KOH / g to 650 mg KOH / g; even more preferably, a functionality in the range of 3.9 to 7.0 and an OH value in the range of 390 mg KOH / g to 550 mg KOH / g; specifically, a functionality in the range of 4.0 to 6.5 and an OH value in the range of 400 mg KOH / g to 510 mg KOH / g.

[0095] Polyol P2)

[0096] The polyol (P2) is preferably a reaction product of an amine, a polyol, an alkoxylation product of the above compounds, and / or a mixture thereof with a C2 to C4 epoxide. Possible initiator compounds for polyether polyols (P2) include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,2,4-butanetriol, 1,3,5-pentanetriol, erythritol, pentaerythritol, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluene, toluenediamine, especially o-toluenediamine, naphthylamine, ethylenediamine, diethylenetriamine, 4,4'-methylenediphenylamine, 1,3-propanediamine, 1,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other diols or polyols or monofunctional or polyfunctional amines.

[0097] Polyols are preferred initiator compounds for polyol P2. Preferably, polyol P2 is the reaction product of a polyol, an alkoxylated product of a polyol, and / or a mixture thereof with a C2 to C4 epoxide. More preferably, polyol P2 is the reaction product of glycerol, trimethylolpropane, an alkoxylated product of the above compounds, and / or a mixture thereof with a C2 to C4 epoxide. Particularly preferably, polyol P2 is the reaction product of glycerol, trimethylolpropane, an alkoxylated product of the above compounds, and / or a mixture thereof with ethylene oxide, propylene oxide, or a mixture of ethylene oxide and propylene oxide.

[0098] The polyol P2 has an OH value of at least 300 mg KOH / g, preferably at least 330 mg KOH / g, and more preferably at least 360 mg KOH / g. The polyether polyol P2 has an OH value of at most 450 mg KOH / g, preferably at most 430 mg KOH / g, and more preferably at most 410 mg KOH / g. Preferably, the OH value of the polyether polyol P2 is in the range of 300 mg KOH / g to 450 mg KOH / g, more preferably in the range of 330 mg KOH / g to 430 mg KOH / g, and even more preferably in the range of 360 mg KOH / g to 410 mg KOH / g.

[0099] The polyether polyol (P2) has a functionality of at least 2.5, preferably at least 2.6, and more preferably at least 2.8. The polyol (P2) has a functionality of at most 3.5, preferably at most 3.4, and more preferably 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, and more preferably in the range of 2.8 to 3.3.

[0100] In a preferred configuration, the polyol P2) has a functionality in the range of 2.5 to 3.5 and an OH value in the range of 300 mg KOH / g to 450 mg KOH / g. More preferably, the polyol P2) has a functionality in the range of 2.5 to 3.5 and an OH value in the range of 330 mg KOH / g to 430 mg KOH / g. Even more preferably, the polyol P2) has a functionality in the range of 2.8 to 3.3 and an OH value in the range of 360 mg KOH / g to 410 mg KOH / g.

[0101] Polyol P3)

[0102] Polyol P3 is preferably a reaction product of an amine, a polyol, an alkoxylated product of the above compounds, or a mixture thereof with a C2 to C4 epoxy alkane. Possible initiator compounds for polyether polyol P3 are, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, trimethylolpropane, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,2,4-butanetriol, 1,3,5-pentanetriol, methylamine, ethylamine, dimethylaminopropylamine, isopropylamine, butylamine, benzylamine, aniline, toluene, toluenediamine, especially o-toluenediamine, naphthylamine, ethylenediamine, diethylenetriamine, 4,4'-methylenediphenylamine, 1,3-propanediamine, 1,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other diols or polyols or monofunctional or polyfunctional amines.

[0103] Preferably, polyol P3) is a reaction product of amines, polyols, alkoxylated products of polyols, and / or mixtures thereof with ethylene oxide, propylene oxide, and / or mixtures of ethylene oxide and propylene oxide. Preferably, polyol P3) is a reaction product of propylene glycol, ethylene glycol, glycerol, trimethylolpropane, toluenediamine, alkoxylated products of the above compounds, and / or mixtures thereof with ethylene oxide, propylene oxide, and / or mixtures of ethylene oxide and propylene oxide. Particularly preferably, polyol P3) is a reaction product of propylene glycol, glycerol, trimethylolpropane, toluenediamine, alkoxylated products of the above compounds, or mixtures thereof with ethylene oxide, propylene oxide, and / or mixtures of ethylene oxide and propylene oxide.

[0104] The polyol P3 has an OH value of at least 40 mg KOH / g, preferably at least 45 mg KOH / g. The polyether polyol P3 has an OH value of up to 260 mg KOH / g, preferably up to 250 mg KOH / g, more preferably up to 200 mg KOH / g. Preferably, the OH value of the polyether polyol P3 is in the range of 40 mg KOH / g to 260 mg KOH / g, more preferably in the range of 45 mg KOH / g to 250 mg KOH / g, and even more preferably in the range of 45 mg KOH / g to 200 mg KOH / g.

[0105] The polyether polyol (P3) has a functionality of at least 1.8, preferably at least 1.9. The polyol (P3) has a functionality of at most 4.1, preferably at most 3.9, more preferably 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 preferably in the range of 1.9 to 3.2.

[0106] In a preferred configuration, the polyol P3) has a functionality in the range of 1.8 to 4.1 and an OH value in the range of 40 mg KOH / g to 260 mg KOH / g; more preferably, the polyol P3) has a functionality in the range of 1.9 to 3.9 and an OH value in the range of 45 mg KOH / g to 250 mg KOH / g; and even more preferably, the polyol P3) has a functionality in the range of 1.9 to 3.2 and an OH value in the range of 45 mg KOH / g to 200 mg KOH / g.

[0107] Polyol P4)

[0108] Polyol P4) is a reaction product of an amine with a C2 to C4 epoxide. Preferably, polyol P4) is a reaction product of ethylenediamine, toluenediamine, and / or dimethylaminopropylamine with ethylene oxide, propylene oxide, or a mixture of ethylene oxide and propylene oxide. Particularly preferably, polyol P4) is a reaction product of ethylenediamine with ethylene oxide, propylene oxide, or a mixture of ethylene oxide and propylene oxide.

[0109] The polyol P4 has an OH value of at least 600 mg KOH / g, preferably at least 630 mg KOH / g, and more preferably at least 660 mg KOH / g. The polyether polyol P4 has an OH value of at most 800 mg KOH / g, preferably at most 790 mg KOH / g, and more preferably at most 780 mg KOH / g. Preferably, the OH value of the polyether polyol P4 is in the range of 600 mg KOH / g to 800 mg KOH / g, more preferably in the range of 630 mg KOH / g to 790 mg KOH / g, and even more preferably in the range of 660 mg KOH / g to 780 mg KOH / g.

[0110] Based on the total weight of polyols P), the amount of at least one polyether polyol P1 is preferably at least 20 wt.-%, more preferably at least 25 wt.-%, and even more preferably at least 30 wt.-%. Based on the total weight of polyols P), the amount of at least one polyether polyol P1 is preferably at most 60 wt.-%, more preferably at most 55 wt.-%, and even more preferably at most 50 wt.-%. Preferably, based on the total weight of polyols P), the amount of at least one polyether polyol P1 is 20 wt.-% to 60 wt.-%, more preferably 25 wt.-% to 55 wt.-%, and even more preferably 30 wt.-% to 50 wt.-%.

[0111] Based on the total weight of polyols P), the amount of at least one polyol P2 is preferably at least 20 wt.-%, more preferably at least 25 wt.-%, and even more preferably at least 30 wt.-%. Based on the total weight of polyols P), the amount of at least one polyether polyol P1 is preferably at most 60 wt.-%, more preferably at most 55 wt.-%, and even more preferably at most 50 wt.-%. Preferably, based on the total weight of polyols P), the amount of at least one polyol P2 is 20 wt.-% to 60 wt.-%, more preferably 25 wt.-% to 55 wt.-%, and even more preferably 30 wt.-% to 50 wt.-%.

[0112] Based on the total weight of polyols P), the amount of at least one polyol P3 is preferably at least 5 wt.-%, more preferably at least 6 wt.-%, and even more preferably at least 8 wt.-%. Based on the total weight of polyols P), the amount of at least one polyol P3 is preferably at most 20 wt.-%, more preferably at most 18 wt.-%, and even more preferably at most 16 wt.-%. Preferably, based on the total weight of polyols P, the amount of at least one polyol P3 is 5 wt.-% to 20 wt.-%, more preferably 6 wt.-% to 18 wt.-%, and even more preferably 8 wt.-% to 16 wt.-%.

[0113] When the polyol P) comprises at least one polyol P4), the amount of at least one polyol P4) based on the total weight of the polyol P) is preferably at least >0 wt.-%, more preferably at least 5 wt.-%, and even more preferably at least 10 wt.-%. When the polyol P) comprises at least one polyol P4), the amount of at least one polyol P4) based on the total weight of the polyol P) is preferably at most 22 wt.-%, more preferably at most 20 wt.-%, and even more preferably at most 18 wt.-%. When the polyol comprises at least one polyol P4), the amount of at least one polyol P4) based on the total weight of the polyol P) is preferably >0 wt.-% to 22 wt.-%, more preferably 5 wt.-% to 20 wt.-%, and even more preferably 10 wt.-% to 18 wt.-%.

[0114] In a preferred embodiment, the amount of at least one polyether polyol P1 is 20 wt.-% to 60 wt.-%, the amount of at least one polyol P2 is 20 wt.-% to 60 wt.-%, and the amount of at least one polyol P3 is 5 wt.-% to 20 wt.-%, wherein all amounts are based on the total weight of the polyols P).

[0115] In a preferred embodiment, the amount of at least one polyether polyol P1 is 20 wt.-% to 60 wt.-%, the amount of at least one polyol P2 is 20 wt.-% to 60 wt.-%, the amount of at least one polyol P3 is 5 wt.-% to 20 wt.-%, and the amount of at least one polyol P4 is >0 wt.-% to 22 wt.-%, wherein all amounts are based on the total weight of the polyols P).

[0116] In addition to P1) to P4), polyol P) may also include additional polyols. The amount of polyols other than P1) to P4) is preferably 0%-25%, more preferably 0%-15%, and even more preferably 0%-10%. Preferably, polyol P) does not include additional polyols other than P1) to P4).

[0117] 4,4-Methylenebis(2,6-diethylaniline) (c)

[0118] The amount of 4,4-methylenebis(2,6-diethylaniline) is preferably at least 0.2 wt.-%, more preferably at least 0.4 wt.-%, and particularly preferably at least 0.5 wt.-%, based on the total weight of all components reacting with at least one diisocyanate or polyisocyanate or mixture thereof. The amount of 4,4-methylenebis(2,6-diethylaniline) is preferably at most 5 wt.-%, more preferably at most 4 wt.-%, and particularly preferably at most 3 wt.-%, based on the total weight of all components mixed with at least one diisocyanate or polyisocyanate or mixture thereof.

[0119] Based on the total weight of all components mixed with at least one diisocyanate or polyisocyanate or mixtures thereof, the amount of 4,4-methylenebis(2,6-diethylaniline) is preferably in the range of 0.2 wt.-% to 5 wt.-%, more preferably in the range of 0.4 wt.-% to 4 wt.-%, and even more preferably in the range of 0.5 wt.-% to 3 wt.-%.

[0120] Foaming agent (d)

[0121] Foaming agents can be chemical foaming agents, physical foaming agents, or mixtures of chemical and physical foaming agents. "Chemical foaming agent" should be understood as a compound that reacts with isocyanates to form a gaseous product. Examples of chemical foaming agents are water and acids, particularly water, formic acid, and mixtures of water and acids. Water is a preferred chemical foaming agent.

[0122] Preferably, the foaming agent includes water.

[0123] Based on the total weight of all components mixed with at least one diisocyanate or polyisocyanate or mixtures thereof, the amount of water is preferably at least 0.5 wt.-%, preferably at least 0.6 wt.-%, more preferably at least 0.7 wt.-%. The amount of water is preferably at most 5 wt.-%, more preferably at most 4 wt.-%, and even more preferably at most 3 wt.-%. Preferably, the amount of water is in the range of 0.5 wt.-% to 5 wt.-%, more preferably in the range of 0.6 wt.-% to 4 wt.-%, and even more preferably in the range of 0.7 wt.-% to 3 wt.-%.

[0124] The foaming agent may include water and at least one additional chemical foaming agent. Preferably, the total amount of the chemical foaming agent is at least 0.5 wt.-%, more preferably at least 0.6 wt.-%, and even more preferably at least 0.7 wt.-%, based on the total amount of the components mixed with at least one diisocyanate or polyisocyanate or mixture thereof. The total amount of the chemical foaming agent is preferably at most 6 wt.-%, more preferably at most 5 wt.-%, and even more preferably at most 4 wt.-%, based on the total amount of the components mixed with at least one diisocyanate or polyisocyanate or mixture thereof.

[0125] Of particular preference is the use of water as the sole chemical foaming agent. One advantage of using water instead of other chemical foaming agents such as formic acid or other acids is its ease of handling without the need for safety precautions.

[0126] Preferably, the blowing agent comprises water and a physical blowing agent. Suitable physical blowing agents that can be used are generally all hydrocarbons known to those skilled in the art as blowing agents, such as non-halogenated hydrocarbons and halogenated olefins, preferably fluorinated olefins.

[0127] Examples of fluorinated olefins are propylene, butene, pentene, and hexene having 3 to 6 fluorine substituents, wherein other substituents such as chlorine may be present, for example tetrafluoropropylene, chlorofluoropropylene (e.g., trifluoromonochloropropylene), pentafluoropropylene, chlorofluorobutene, hexafluorobutene, or mixtures thereof. Preferred are 1,1,1,3-tetrafluoropropylene, 1,1,1-trifluoro-2-chloropropylene, 1-chloro-3,3,3-trifluoropropylene, 1,1,1,2,3-pentafluoropropylene, Z-1,1,1,4,4,4-hexafluoro-2-butene, E-1,1,1,4,4,4-hexafluoro-2-butene, 1-bromopentafluoropropylene, 2-bromopentafluoropropylene, 3-bromopentafluoropropylene, 1,1,2,3,3,4,4-heptafluoro- 1-Butene, 1-chloro-2,3,3,3-tetrafluoropropene, 1-bromo-2,3,3,3-tetrafluoropropene, 2-bromo-1,3,3,3-tetrafluoropropene, 3-bromo-1,1,3,3-tetrafluoropropene, 2-bromo-3,3,3-trifluoropropene, E-1-bromo-3,3,3-trifluoropropene, 3,3,3-trifluoro-2-(trifluoromethyl)propene, 1,1,1-trifluoro-2-butene and / or mixtures thereof.

[0128] Examples of non-halogenated hydrocarbon blowing agents are cyclopentane isomers and / or cyclopentane, especially cyclopentane. It is preferred to use cyclopentane isomers and / or cyclopentane. Cyclopentane and mixtures of isopentane and cyclopentane having a cyclopentane content of at least 70 wt.% are preferred, and it is particularly preferred to use cyclopentane having a purity of at least 90 wt.%, especially at least 95 wt.%.

[0129] Preferably, the physical blowing agent is a non-fluorinated olefin. Particularly preferably, the physical blowing agent is selected from the group consisting of: Z-1,1,1,4,4,4-hexafluoro-2-butene, E-1,1,1,4,4,4-hexafluoro-2-butene, 1-chloro-3,3,3-trifluoropropene, and 1-chloro-2,3,3,3-tetrafluoropropene.

[0130] In a preferred embodiment, the amount of physical foaming agent is in the range of ≥0 wt.-% to 35 wt.-% or more preferably 1 wt.-% to 10 wt.-% based on the component mixed with at least one diisocyanate or polyisocyanate or a mixture thereof.

[0131] Preferably, the total amount of at least one blowing agent (d) is 0 wt.-% to 20 wt.-%, more preferably 0.5 wt.-% to 17 wt.-%, and even more preferably 0.7 wt.-% to 15 wt.-%, based on the amount of the component mixed with at least one diisocyanate or polyisocyanate or a mixture thereof. Preferably, the blowing agent is used in an amount such that the resulting foam has a free-rising density in the range of 60 g / l to 200 g / l.

[0132] Catalyst (e)

[0133] It is possible to use all compounds that accelerate isocyanate-water or isocyanate-polyol reactions as catalysts. Such compounds are known and described, for example, in “Polyurethane Handbook,” Carl Hanser Publishers, 2nd edition, 1993, Chapter 3.4.1. These compounds include amine-based catalysts and organometallic compound-based catalysts. It is possible to use, for example, organotin compounds, such as tin(II) salts of organic carboxylic acids, such as tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate, and tin(II) laurate; and dialkyltin(IV) salts of organic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate; and also bismuth carboxylate, such as bismuth(III) neodecanoate, bismuth 2-ethylhexanoate, and bismuth octoate; or alkali metal salts of carboxylic acids, such as potassium acetate or potassium formate, as organometallic compound-based catalysts.

[0134] Preferably, at least one tertiary amine is used as the catalyst. These tertiary amines may also contain groups reactive to isocyanates, such as OH, NH, or NH₂ groups. Some of the most commonly used catalysts are bis[2-(N,N-dimethylamino)ethyl] ether,

[0135] 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. Preferably, a mixture comprising at least two different tertiary amines is used as the catalyst. Preferably, 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.

[0136] Based on the total weight of all components mixed with at least one diisocyanate or polyisocyanate or a mixture thereof, and based on the amount of components mixed with at least one diisocyanate or polyisocyanate or a mixture thereof, the amount of catalyst is preferably in the range of 0 wt.-% to 5 wt.-%, more preferably in the range of 0.3 wt.-% to 4.5 wt.-%, and even more preferably in the range of 0.5 wt.-% to 4 wt.-%.

[0137] Foam stabilizer (f)

[0138] Foam stabilizers are added to stabilize polyurethane foam. Foam stabilizers are materials that promote the formation of a regular cell structure during foaming and are also referred to below as surfactants. Examples include foam stabilizers containing silicones, also known as silicone surfactants, such as siloxane oxide copolymers and other organopolysiloxanes. Other examples include fatty alcohols, carbonyl alcohols, fatty amines, alkylphenols, dialkylphenols, alkylcresols, alkylresorcinols, naphthols, alkylnaphthols, naphthylamines, anilines, alkylanilines, toluidines, bisphenol A, alkylated bisphenol A, alkoxylated products of polyvinyl alcohol, and alkoxylated products of formaldehyde with alkylphenols, formaldehyde with dialkylphenols, formaldehyde with alkylcresols, formaldehyde with alkylresorcinols, formaldehyde with anilines, formaldehyde with toluidine, formaldehyde with naphthol, formaldehyde with alkylnaphthols, and alkoxylated products of formaldehyde with bisphenol A, or mixtures of two or more of these foam stabilizers.

[0139] Based on the total weight of all components mixed with at least one diisocyanate or polyisocyanate or a mixture thereof, and based on the amount of components mixed with at least one diisocyanate or polyisocyanate or a mixture thereof, the amount of foam stabilizer is preferably in the range of 0 wt.-% to 5 wt.-%, more preferably in the range of 0.5 wt.-% to 4.5 wt.-%, and even more preferably in the range of 0.8 wt.-% to 4 wt.-%.

[0140] Other adjuvants and / or additives

[0141] In a preferred embodiment, the component mixed with at least one diisocyanate or polyisocyanate or a mixture thereof may include a foam stabilizer (f) and other components such as additives and auxiliaries.

[0142] Optionally, additional auxiliaries and / or additives may be added to the polyurethane foam reaction mixture. Examples include, for instance, surfactants, antioxidants, chain extenders, crosslinking agents, pore conditioners, fillers, dyes, pigments, flame retardants, hydrolysis inhibitors, antifungal substances, and antibacterial substances.

[0143] Chain extenders and crosslinking agents typically have molecular weights between 60 g / mol and 300 g / mol. Bifunctional chain extenders, trifunctional crosslinking agents, and higher-functionality crosslinking agents, or mixtures thereof (if suitable), may be added. The chain extenders and / or crosslinking agents used are preferably alkanolamines, and particularly diols and / or triols with molecular weights preferably between 60 g / mol and 300 g / mol.

[0144] Optionally, flame retardants can be used as additives to polyurethane foam. Generally, it is possible to use flame retardants known in the prior art.

[0145] More detailed information on the starting materials, foaming agents, catalysts, and auxiliaries and / or additives used in carrying out the methods according to the invention can be found, for example, in “Polyurethane Handbook”, Carl Hanser Publishers, 2nd edition, mid-1993.

[0146] In a preferred embodiment, a polyol (P), 4,4-methylenebis(2,6-diethylaniline) (c), at least one blowing agent (d), at least one catalyst (e), and optionally at least one foam stabilizer (f), along with additives and / or auxiliaries (if present), are mixed together to form a polyol component. The polyol component is one aspect of the invention. The polyol component is then reacted with a diisocyanate or polyisocyanate, or a mixture thereof, and (if suitable) optionally a blowing agent. This two-component method has proven particularly advantageous.

[0147] When producing foam according to the method of the present invention, it is preferable to react the polyisocyanate and the isocyanate reactive compound with an isocyanate index of 80-140, more preferably 90-130, or even more preferably 100-120.

[0148] Preferably, the reaction mixture is prepared by mechanically mixing the components, preferably in a high-pressure mixing head. Preferably, the mixing head is operated automatically.

[0149] In step II, a layered structure comprising an object and a substrate is formed, wherein a polyurethane foam reaction mixture forms an intermediate layer between the object and the substrate. The polyurethane foam layer can be used as an adhesive to attach the object to the substrate.

[0150] Before the object comes into contact with the substrate, the polyurethane foam reaction mixture can be applied to the substrate, the object, or both. Preferably, the polyurethane foam reaction mixture is applied to the substrate or the object. More preferably, the polyurethane foam reaction mixture is applied to the object.

[0151] The polyurethane foam reaction mixture is preferably applied by pouring. In a preferred embodiment, a pouring mixing head is used to apply the polyurethane foam reaction mixture. The advantages of pouring instead of spraying include avoiding workplace contamination and a less complex production method, as the precautions necessary for spraying are not required. In a preferred embodiment, the application of the polyurethane foam reaction mixture is automated. During application, the object or substrate to which the polyurethane foam reaction mixture has been applied can be placed on a conveyor belt, held or positioned by a robotic arm on another type of device that facilitates automation. Preferably, the object or substrate to which the polyurethane foam reaction mixture has been applied is held by a robotic arm.

[0152] After the polyurethane foam reaction mixture has been applied, the object or substrate to which the reaction mixture has been applied can be rotated or otherwise moved after a short waiting period. This rotation or movement can be performed by a robotic arm or another type of device that facilitates automation. Preferably, the object or substrate to which the polyurethane foam reaction mixture has been applied can be rotated or otherwise moved after 10 seconds, more preferably after 7 seconds, and particularly preferably after 5 seconds, without the polyurethane foam reaction mixture dripping from the surface to which it has been applied. This ability to rotate or otherwise move the object or substrate to which the polyurethane foam reaction mixture has been applied after a short period allows for automation of the method and ensures that the waiting time in step II is short enough to facilitate an efficient production process.

[0153] After applying the polyurethane foam reaction mixture to an object, a substrate, or both, a layered structure comprising the object and the substrate is formed, such that the polyurethane foam reaction mixture forms an intermediate layer between the object and the substrate. The layered structure is formed using the polyurethane foam reaction mixture as an intermediate layer before the polyurethane foam reaction mixture hardens.

[0154] The formation of the layered structure is preferably an automated process step. The formation of the layered structure can be performed by a robotic arm or another type of device that facilitates automation. To form the layered structure in step II, a substrate or object can be placed in a mold. Alternatively, the layered structure can be formed such that neither the substrate nor the object is placed in a mold. Preferably, neither the object nor the substrate is placed in a mold during step II.

[0155] The formation of a layered structure is performed to leave sufficient space for the polyurethane foam reaction mixture between the object and the substrate. To achieve this, the substrate and object can be held at a defined distance from each other, or spacers can be inserted between them to maintain the defined distance. Particularly in automated methods, if the distance between the substrate and object can be reliably kept constant, the substrate and object can be held at a defined distance from each other without the use of spacers. For example, this can be achieved by using a robotic arm to hold and move the object or substrate. However, automated methods can also utilize spacers between the object and the substrate.

[0156] Regardless of whether spacers are used, the substrate and the object are held at a certain distance from each other for a certain period of time before release. The distance is selected such that the polyurethane foam reaction mixture forms an intermediate layer between the object and the substrate and contacts both. The distance is selected such that the polyurethane foam layer formed when the polyurethane foam reaction mixture cures in step III has a thickness suitable for the application. For example, the distance between the object and the substrate can be in the range of 2 mm to 50 mm, preferably in the range of 3 mm to 40 mm, and most preferably in the range of 4 mm to 30 mm. The final thickness of the cured polyurethane foam layer can be greater than the thickness of the substrate and the object held at the distance for a certain period of time. For example, a higher final thickness may be caused by post-expansion of the polyurethane foam. For example, the final thickness of the cured polyurethane foam can be up to 10 mm, 7 mm, or 5 mm higher than the thickness of the substrate and the object held at the distance for a certain period of time. Other thickness differences are also possible. This difference depends on the application, including the design of the object and the substrate, and the manufacturing conditions.

[0157] The polyurethane foam reaction mixture and / or cured polyurethane foam may extend along the edges of an object. For example, the reaction mixture and / or cured polyurethane foam may seep out at all or partially along the edges of an object.

[0158] The duration for which the substrate and object are held at a distance from each other before release is selected to allow sufficient curing of the polyurethane foam reaction mixture (step III), thereby ensuring the stability of the structural object formed by the object, intermediate layer, and substrate. Stability means that the object and substrate are attached sufficiently firmly to maintain the integrity of the layered structure when it is moved or further processed. Preferably, the duration for which the substrate and object are held at a distance from each other before release is at most 100 seconds, more preferably at most 70 seconds, and even more preferably at most 40 seconds.

[0159] The layered structure may include additional components. These additional components may be adjacent to and / or incorporated between the object and the substrate. The additional components may be at least partially incorporated into an intermediate layer between the object and the substrate, which is formed from a polyurethane foam reaction mixture. Prior to forming the layered structure comprising the object and the substrate, the additional components may be attached to the object or substrate to form a pre-assembled unit, which is then attached to an object or substrate that is not part of the pre-assembled unit. They may also be incorporated between the object and the substrate in the same method step of forming the layered structure comprising the object and the substrate, or attached to the object or substrate after forming the layered structure comprising the object and the substrate using a polyurethane foam reaction mixture as an intermediate layer between the object and the substrate.

[0160] In a preferred embodiment, the layered structure includes cooling components. Cooling components such as condensers may be incorporated between the object and the substrate. Preferably, the object is a vacuum-insulated panel, the substrate is the outer wall of the cooling device, the wall of the inner container of the cooling device, the outer wall of the door of the cooling device, or the lining or door of the cooling device, and the cooling components such as condensers are incorporated between the object and the substrate.

[0161] Preferably, the layered structure includes a heat insulation layer. Preferably, the layered structure includes a heat insulation layer, and the object is a vacuum-insulated panel, and the substrate is the inner side of the outer wall of the cooling device, the outer side of the wall of the inner container of the cooling device, or the inner side of the outer wall of the door of the cooling device. The layered structure including the heat insulation layer may additionally include cooling components. The heat insulation layer may be polyurethane foam. Suitable polyurethane foams are described, for example, in EP3990512 and EP3856815.

[0162] In step III, the polyurethane foam reaction mixture is cured to form a polyurethane foam layer.

[0163] The polyurethane foam reaction mixture preferably has a thickening time in the range of 0-10 seconds at 30°C, more preferably in the range of 0-7 seconds at 30°C, and even more preferably in the range of 0-5 seconds at 30°C.

[0164] Preferably, the polyurethane foam is a rigid foam. The polyurethane foam preferably has a free-blooming density in the range of 60 g / l to 200 g / l, more preferably in the range of 60 g / l to 180 g / l, and particularly preferably in the range of 60 g / l to 160 g / l.

[0165] The polyurethane foam preferably has a gel time in the range of 10 to 35 seconds at 30°C, more preferably in the range of 12 to 27 seconds at 32°C, and even more preferably in the range of 15 to 30 seconds at 30°C.

[0166] Preferably, the method according to the invention further includes step IV, in which the object or substrate is released; and step V, in which the method is restarted. In step V, a new object and / or a new substrate may be set to form a second or another layered structure. A series of layered structures can be prepared in this manner.

[0167] Another aspect of the invention is a layered structure comprising an object, a polyurethane foam layer, and a substrate, wherein the layered structure can be produced by the method according to the invention.

[0168] Another aspect of the present invention is the use of a layered structure prepared according to the method of the present invention, or a layered structure according to the present invention, for insulating a refrigerator.

[0169] The method according to the invention enables effective attachment of an object to a substrate. It is suitable for automated processes. Even if the object or substrate to which the polyurethane foam reaction mixture has been applied is rotated or otherwise moved, the polyurethane foam reaction mixture, acting as an adhesive, will not drip after application. This ensures that the object or substrate can be moved freely after the polyurethane foam reaction mixture has been applied. Furthermore, the curing time of the polyurethane foam reaction mixture is short enough for automated processes, yet long enough to ensure that the polyurethane foam does not harden prematurely. The absence of a long waiting period after application of the reaction mixture is crucial for automated industrial processes. Moreover, the object or substrate can be handled by robotic arms or other automated systems and can be moved and rotated freely by them. There is no need to place the object, substrate, or both in a mold for the attachment step, which reduces the complexity of the attachment step and the number of components required. The method according to the invention enables attachment of objects and substrates even if the object, substrate, or both are not planar. For example, the object, substrate, or both may have an embossed surface structure and / or include protrusions and / or pits, such as ribbed or honeycomb structures. This method avoids workplace contamination that would occur with the application of the polyurethane foam reaction mixture by spraying.

[0170] Experimental Section

[0171] Measurement method:

[0172] Measurement of hydroxyl value:

[0173] The hydroxyl value is determined according to DIN 53240 (1971-12).

[0174] Cup density:

[0175] The cup density is determined by measuring the foam density in the core according to DIN EN ISO 845.

[0176] Milk thickening time:

[0177] The time from the start of mixing the reaction mixture to the start of foam expansion.

[0178] Gel time (setting time / fiber time):

[0179] The time from the start of mixing the reaction mixture until it is possible to draw out the foam (e.g., with a wooden stick). Therefore, this point represents the transition from liquid to solid.

[0180] Dripping behavior:

[0181] Thixotropy and related dripping behavior were tested on a VIP panel. To do this, 150g of the reaction mixture was foamed on the VIP panel and inverted after 10 seconds. If the mixture dripped, the formulation was unsuitable. If the reaction mixture did not drip, the test was repeated after 5 seconds.

[0182] raw materials

[0183] i) Polyols

[0184] Polyol 1: A polyether polyol based on sucrose, glycerol, and propylene oxide (PO), with an OH value of 490 mg KOH / g and a functionality of 4.34.

[0185] Polyol 2: A polyether polyol based on glycerol and PO, OH value: 400 mg KOH / g; functionality: 2.99*

[0186] Polyol 3: A polyether polyol based on propylene glycol and PO, OH value: 55 mg KOH / g; functionality: 1.93**

[0187] Polyol 4: A polyether polyol based on ethylenediamine and PO, with an OH value of 750 mg KOH / g and a functionality of 4.0.

[0188] *The functionality of polyol 2 is <3 because a small amount of water is present, which is added by adding the catalyst to the initiator glycerol.

[0189] **The functionality of polyol 3 is <2 because a small amount of water is present, which is added by adding the catalyst to the initiator propylene glycol.

[0190] ii) Catalyst

[0191] Catalyst 1: Lupragen N 201 (BASF)

[0192] Catalyst 2: Lupragen N 206 (BASF)

[0193] Catalyst 3: Bis(2-dimethylaminoethyl) ether

[0194] iii) Additives

[0195] Surfactant: Tegostab from Evonik ® B 84204 (Stabilizer)

[0196] Crosslinking agent 1: diethyltoluenediamine

[0197] Crosslinking agent 2: 4,4-methylenebis(2,6-diethylaniline)

[0198] Crosslinking agent 2: O,O'-bis(2-aminopropyl)polypropylene glycol

[0199] iv) Isocyanates

[0200] Isocyanate 1: A polymeric MDI with a viscosity of 210 mPas at 25°C.

[0201] Components i) through iii) were mixed to obtain a polyol component and then reacted with isocyanate iv). The amounts of raw materials used are shown in Tables 1 and 2. CE indicates a comparative example, and E indicates an inventive example. E3 is a machine operation, and E1-E2, E4-E6, and all comparative examples are laboratory examples.

[0202] In E3, mixing is performed in the mixing head. Machine settings (Hennecke TopLine HK 650 / 650 / 45 P): discharge 150 g / s, pressure at the mixing head (MT18-4, Hennecke), 150 bar, component temperature 30°C.

[0203] Metal sheet: 500×500×1mm

[0204] Vacuum panel: 500×500×40mm (core material: open-cell PU foam)

[0205] Spacer: 46mm

[0206] PU foam (compressed) layer thickness: 5mm

[0207] Table 1

[0208] Formula E1 E2 E3 CE1 CE2 CE3 CE4 CE5 Polyol 1 35.3 35.3 35.3 6 50 50 50 50 50 Polyol 2 36.1 36.1 35.1 8 36.1 36.1 36.1 36.1 36.1 36.1 Polyol 3 10.5 10.5 10.4 6 3 10.5 10.5 10.5 10.5 10.5 Polyol 4 13.8 13.8 13.8 2 5 10 15 20 Stabilizer 1.5 1.5 1.4 6 1.5 1.5 1.5 1.5 1.5 Catalyst 1 1.65 1.65 1.64 1.65 1.65 1.65 1.65 Catalyst 2 0.5 0.5 0.5 0.5 Catalyst 3 0.35 0.35 0.36 00 0.35 Water 0.800 0.800 0.820 0.80 0.80 0.80 0.8 Crosslinking agent 11 Crosslinking agent 20.500 1.000 0.900 Crosslinking agent 3 Isocyanate Isocyanate 1100 100 100 100 100 100 100 Parameter index 105 105 105 105 105 105 105 Emulsion thickening time 13 13 Not measured 14 13 12 12 14 Gel time 35 35 Not measured 44 413 73 44 4 Cup density (g / l) 115 115 Not measured 121 122 122 121 121 Dripping behavior No dripping after 5 seconds No dripping after 5 seconds No dripping after 5 seconds Dripping after 10 seconds Dripping after 10 seconds Dripping after 10 seconds Dripping after 10 seconds Dripping after 10 seconds Dripping after 10 seconds surface

[0209] Table 2

[0210] Formula CE6CE7E4E5E6CE8CE9CE10CE11 Polyol 1505050505035.335.335.335.3 Polyol 236.136.136.136.136.136.136.136.136.1 Polyol 310.510.510.510.510.510.510.510.510 .510.5 Polyol 413.813.813.813.8 Stabilizer 1.51.51.51.51.51.51.51.5 Catalyst 11.651.651.651.651.651.651.651.651.65 Catalyst 2 Catalyst 30.350.350.350.350.350.350.350.350 0.35 0.35 Water 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Crosslinking agent 12 Crosslinking agent 20.5 1.0 1.5 Crosslinking agent 30.5 12 Isocyanate Isocyanate 1100 100 100 100 100 100 100 100 Parameter index 105 105 105 105 105 105 105 105 105 Emulsion thickening time 131414141414131211 Gel time 394848484636353331 Cup density (g / l) 120111113117115116110107106 Dropping behavior: Dropping after 10 seconds, Dropping after 10 seconds, No dripping after 5 seconds, No dripping after 5 seconds, No dripping after 5 seconds, Dropping after 10 seconds, Dropping after 10 seconds, Dropping after 10 seconds surface

[0211] The inventive example does not show dripping, while in the comparative example, the polyurethane foam reaction mixture drips from the substrate.

[0212] Robot-assisted application test 1

[0213] The optimal application method and the amount of reaction mixture were tested using a 6-axis robot (ABB) and a mold frame (FRIMO's universal frame).

[0214] Machine settings (Elastogran Maschinenbau 30 / 80 IQ): emission rate 100 g / s, pressure at mixing head (MT18, Hennecke) 120 bar, component temperature 30°C.

[0215] Metal sheet: 1000×640×1mm

[0216] 1600×640×1mm

[0217] Vacuum panel: 700×385×15mm (core material: silicon dioxide).

[0218] 1450×465×15mm (core material: silicon dioxide)

[0219] Spacer: 22mm

[0220] PU foam (compressed) layer thickness: 6mm

[0221] Polyurethane foam reaction mixture: prepared according to Invention Example E3

[0222] First, the vacuum panel was wrapped with a PE film to allow for further separation of the vacuum panel from the PU foam. The vacuum panel was then attached to the metal sheet using a universal frame from FRIMO. For this purpose, a vacuum cup was used to bond the panel to the upper frame, and a polyurethane reaction mixture was applied to the metal sheet on the lower frame. A 22mm thick spacer was used between the upper and lower frames to achieve a uniform PU layer thickness of 6mm. After a 45-second demolding time, the frame was opened, the VIP panel was removed, and the result was checked. The robot's path, speed, and associated application amount were optimized until the VIP panel adhered to the surface and some material expanded on the sides. Subsequently, the VIP panel was bonded without the PE film to confirm the result again. The VIP panel was then uniformly and firmly attached to the metal sheet.

[0223] Robot-assisted application test 2

[0224] Foam behavior test when using only a 6-axis robot (ABB) without a mold rack

[0225] Machine settings (Cannon A-100): Discharge rate 50 g / s, pressure at mixing head (FPL 10, Cannon) 140 bar, component temperature 30°C.

[0226] Metal sheet: 1100×630×0.5mm

[0227] Vacuum panel: 700×385×15mm (core material: silicon dioxide)

[0228] 965×580×40mm (core material: open-cell PU foam)

[0229] PU foam (compressed) layer thickness: 5mm

[0230] Polyurethane foam reaction mixture: prepared according to Invention Example E3

[0231] The VIP panel is received using a robot-compatible vacuum holding device, moved beneath a mixing head, and the reaction mixture foams at the application method (travel path) and speed to be tested. The amount of reaction mixture is selected such that polyurethane foam partially seeps out from the sides of the panel. The panel is then inverted and held at an appropriate distance (5 mm) above the sheet, with the foam sides facing down, allowing the foam to expand there. After 45 seconds, the panel and sheet are bonded together. To initially determine the optimal travel path and speed, the panel is wrapped in a PE film. After the foaming process, the panel can be removed and the distribution checked. Once everything is optimized, the panel is firmly bonded without the PE film, and the adhesion is then checked. As a result, the VIP panel is uniformly and firmly attached to the metal sheet.

Claims

1. A method for forming a layered structure comprising an object, a polyurethane foam layer, and a substrate, the method comprising the following steps: I. A polyurethane foam reaction mixture is prepared by mixing at least the following: a. at least one diisocyanate or polyisocyanate or a mixture thereof; b. a polyol P), said polyol P including b1) at least one polyether polyol P1), said polyether polyol P1) having a functionality in the range of 3.5-8 and an OH value in the range of 350 mg KOH / g to 800 mg KOH / g, wherein at least one initiator compound of said polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide and / or sugar alcohol and has at least 4 active hydrogen atoms; b2) at least one polyol P2), said polyol P2) having a functionality in the range of 2.5-3.5 and an OH value in the range of 300 mg KOH / g-450 mg KOH / g; and b3) at least one polyol P3), said polyol P3) having a functionality in the range of 1.8-4.1 and an OH value in the range of 40 mg KOH / g-260 mg KOH / g; c. 4,4-methylenebis(2,6-diethylaniline); d. at least one foaming 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 substrate; and III. curing the polyurethane foam reaction mixture to form a polyurethane foam layer.

2. The method according to claim 1, wherein the polyol P) comprises at least one polyol P4), the polyol P4) being selected from the reaction product of ethylenediamine, toluenediamine and / or dimethylaminopropylamine with epoxide and having an OH value in the range of 600 mg KOH / g to 800 mg KOH / g.

3. The method according to claim 1 or 2, wherein the at least one diisocyanate or polyisocyanate is selected from the group consisting of toluene diisocyanate, methylene diphenyl diisocyanate, methylene diphenyl diisocyanate and mixtures of polyphenyl polymethylene polyisocyanate and / or related isocyanate prepolymers.

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

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

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

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

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

9. The method according to any one of claims 1 to 8, wherein the object is a vacuum-insulated panel, a heat insulation panel, a sound insulation sheet, or a honeycomb sheet.

10. The method according to any one of claims 1 to 9, wherein the substrate is the outer wall of a cooling device, the wall of the inner container of a cooling device, the outer wall of a door of a cooling device, the inner wall of a door of a cooling device, the liner of a door of a cooling device, the outer wall of a dishwasher, or the wall of the inner container of a dishwasher.

11. The method according to any one of claims 1 to 10, wherein the object is a vacuum-insulated panel, and the substrate is the outer wall of the cooling device, the wall of the inner container of the cooling device, the inner wall of the door of the cooling device, the outer wall of the door of the cooling device, or the lining of the door of the cooling device.

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

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

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

15. A layered structure comprising an object, a polyurethane foam layer, and a substrate, wherein the layered structure is capable of being produced by the method according to any one of claims 1 to 14.

16. The use of a layered structure prepared according to any one of claims 1 to 14 or the layered structure according to claim 15 for insulating a cooling device.

17. A polyol component, said polyol component comprising: i. Polyol P), wherein the polyol P comprises i1) 20 wt.-% to 60 wt.-% of at least one polyether polyol P1), wherein the polyether polyol P1) has a functionality in the range of 3.5-8 and an OH value in the range of 350 mg KOH / g to 800 mg KOH / g, wherein at least one initiator compound of the polyether polyol P1) is a monosaccharide, oligosaccharide, polysaccharide and / or sugar alcohol and has at least 4 active hydrogen atoms; i2) 20 wt.-% to 60 wt.-% of at least one polyol P2), wherein the polyol P2) has a functionality in the range of 2.5-3.5 and an OH value in the range of 300 mg KOH / g to 450 mg KOH / g; i3) 5 wt.-% to 20 wt.-% of at least one polyol P3), wherein the polyol P3) has a functionality in the range of 1.8-4.1 and an OH value in the range of 40 mg KOH / g to 260 mg KOH / g. OH values ​​within the range of KOH / g; and the amount of said polyols P1) to P3) is based on the total weight of said polyols P); ii. 0.2 wt.-% to 5 wt.-% 4,4-methylenebis(2,6-diethylaniline); iii. 0 wt.-% to 15 wt.-% at least one foaming agent; iv. 0 wt.-% to 5 wt.-% at least one catalyst; and optionally v. 0 wt.-% to 5 wt.-% at least one foam stabilizer; wherein the amounts of components ii to v are based on the total weight of the polyol components.