Improvement of storage stability of hydrofluoroolefins in amine-containing polyol components for preparing polyurethanes

Abstract

The invention relates to a polyol component for producing polyurethane foams, containing: (a) a compound having at least two hydrogen atoms reactive towards isocyanates; (b) a catalyst comprising at least one polyurethane catalyst (b1) containing at least one tertiary nitrogen atom wherein the tertiary nitrogen atom is part of an aliphatic or aromatic ring and / or is bound to at least one carbon atom that is at least a secondary carbon; and comprising at least one polyurethane catalyst (b2) selected from the group consisting of cyclic amides wherein the polyurethane catalysts (b1) and (b2) do not have dimethylamino groups bound to primary carbon atoms; (c) a blowing agent containing a hydrofluoroolefin; and (d) a suitable additive. Further, the invention comprises a process for preparing a polyurethane foam in which such a polyol component is mixed with an isocyanate component containing at least one polyisocyanate to form a reaction mixture and converted into a polyurethane; and to a polyurethane foam obtained according to this process.

Description

[0001] Specification

[0002] The present invention relates to a polyol component for preparing polyurethane foam, comprising: (a) a compound having at least two hydrogen atoms reactive with isocyanate; (b) a catalyst, the catalyst comprising at least one polyurethane catalyst (b1), the polyurethane catalyst containing at least one tertiary nitrogen atom, wherein the tertiary nitrogen atom is part of an aliphatic or aromatic ring and / or is bonded to at least one carbon atom which is at least secondary; and comprising at least one polyurethane catalyst (b2), the polyurethane catalyst selected from the group consisting of cyclic amides, wherein the polyurethane catalysts (b1) and (b2) do not have a dimethylamino group bonded to a primary carbon atom; (c) a blowing agent, comprising at least one physical blowing agent (c1), the physical blowing agent comprising at least one aliphatic halogenated hydrocarbon compound (c11) of the general formula (1)

[0003]

[0004] wherein the group R 1 to R 4 each independently of one another represents a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or an ethyl group, and the hydrogen atoms in the methyl group or ethyl group may be wholly or partly substituted by chlorine or fluorine, provided that: the compound according to formula (1) consists of 2 to 5 carbon atoms, at least one hydrogen atom and at least two halogen atoms selected from fluorine atoms and chlorine atoms; at least one of the groups R 1 and R 4 and at least one of the groups R 2 and R 3 must have at least one halogen atom; the carbon atom of the carbon-carbon double bond carrying the methyl or ethyl group also carries a hydrogen atom; and (d) additives where appropriate. Further, the present invention includes a method for preparing polyurethane foam, wherein this polyol component is mixed with an isocyanate component containing at least one polyisocyanate to form a reaction mixture, which is then converted into polyurethane; and includes a polyurethane foam obtained according to this method.

[0005] The preparation of polyurethane foam, especially polyurethane foam, is known. In the preparation of polyurethane, the reaction of isocyanate and polyol is usually carried out in the presence of a catalyst (especially a strongly basic amine catalyst), a blowing agent and other auxiliaries and additives. These raw materials are usually formulated by suppliers (usually chemical companies) such that they are customized for specific applications and such that the polyurethane has the desired properties. For this purpose, an isocyanate component containing isocyanate and a polyol component containing components reactive with isocyanate are usually formulated, so that the user only needs to mix these two components to initiate the reaction and produce the desired polyurethane.

[0006] A blowing agent is used in the preparation of polyurethane foams. As blowing agents, chemical blowing agents (such as water or carboxylic acids) and physical blowing agents can be used. In particular, physical blowing agents are usually used in the preparation of rigid polyurethane foams, but they are often also used in combination with chemical blowing agents. Chemical blowing agents are compounds that react with isocyanates and are accompanied by gas generation (usually carbon dioxide). Physical blowing agents are usually low-boiling liquids that evaporate by the heat of reaction during the conversion of isocyanates and polyols, thereby causing the reaction mixture to foam. Due to the high reactivity of isocyanates, in order to avoid side reactions, physical blowing agents are also added to the polyol component.

[0007] In the past, chlorofluorocarbons were mainly used as physical blowing agents. Since chlorofluorocarbons have a damaging effect on the ozone layer, they have been banned in many parts of the world. Nowadays, hydrofluorocarbons (HFCs) and low-boiling hydrocarbons such as pentane are mainly used as physical blowing agents. A criterion here is the storage stability of the components.

[0008] Due to the non-polarity of hydrocarbons (mainly pentane), the solubility of these blowing agents in the polyurethane system is limited. Therefore, in many polyurethane systems, the polyol component is prone to stratification. Therefore, it is advantageous to add the blowing agent shortly before the foaming process to avoid problems with the short storage stability of the polyol component carrying the blowing agent, but this increases the complexity for the user.

[0009] Another problem with using alkanes as blowing agents is their flammability. This increases the flammability of the obtained polyurethane foam. In addition, the components containing alkanes as blowing agents, usually the polyol component, are also flammable. This requires special protective measures during the storage and processing of systems containing alkanes as blowing agents. In addition, alkanes are partially released during the foaming process. The resulting explosion risk requires a large investment in safety equipment.

[0010] Hydrofluorocarbons (HFCs) are always used when the investment in safety equipment required for using hydrocarbons as physical blowing agents is too high or cannot be achieved from an equipment perspective. Compared with hydrocarbons, HFCs also have the additional advantage that they can produce foams with a higher insulation effect. However, due to the impact of HFCs on global warming, that is, they have a high "Global Warming Potential" (GWP), they are highly criticized from an environmental perspective. Therefore, in the European Union, regulations also require first reducing their use and will ban them in the future.

[0011] Accordingly, preferred physical blowing agents have a low global warming potential (GWP). This is precisely where the advantage of halogenated olefins (so-called HFOs, hydrofluoroolefins) lies. The disadvantage of polyol components containing HFOs, especially those containing specific HFOs (such as HFO-1234ze and / or HCFO-1233zd), is the stability of the polyol component. Thus, even short-term storage of polyol components containing HFOs can lead to significant changes in their reaction characteristics and result in a significant reduction in the quality of the foam, and even foam collapse. The low storage stability is here based on the decomposition of the blowing agent in the polyol component. This is described, for example, in WO 2009048807. The degradation reaction of HFO blowing agents can be slowed down by using specific catalysts (such as imidazole derivatives), but this restricts the freedom of formulators and seriously affects and even makes it impossible to optimize the catalytic setting.

[0012] There are various methods to improve the storage stability of polyol components containing halogenated olefins as blowing agents. Most methods are either based on blocking amine catalysts or on using alternative catalysts, such as metal catalysts. In addition, optimized amine catalysts have been described, which have less influence on the storage stability of polyol components due to, for example, steric hindrance. An example is WO 2009048807, which discloses polyol components containing sterically hindered amine catalysts. However, such catalysts are usually expensive.

[0013] WO 2018170107 discloses the use of metal catalysts as substitutes for strongly basic amine catalysts. However, substituting amine catalysts with metal catalysts is not feasible because metal catalysts are strong gel catalysts and cannot be used as substitutes for blowing catalysts to optimize the reaction characteristics. In addition, many metal catalysts have insufficient stability to hydrolysis and thus do not have storage stability in aqueous polyol components, and due to regulatory requirements, the use of some of these metal catalysts has been restricted.

[0014] WO 2009048826 describes the use of blocked amine catalysts, and US20190119461 discloses the use of imidazole-based catalysts. The disadvantage of these catalysts is that they are usually less active, and blocked catalysts usually only unblock at higher temperatures. This requires an additional step to heat the reaction mixture and restricts the freedom in setting the reaction characteristics.

[0015] The object of the present invention is to provide a polyol component containing an HFO blowing agent with storage stability, which does not have the above disadvantages, especially having a catalyst that is inexpensive and can achieve a balanced catalysis of the gel reaction and the blowing reaction.

[0016] The technical solution of the present invention for achieving this purpose is a polyol component for preparing polyurethane foam, comprising: (a) a compound having at least two hydrogen atoms reactive with isocyanate; (b) a catalyst, the catalyst comprising at least one polyurethane catalyst (b1), the polyurethane catalyst containing at least one tertiary nitrogen atom, wherein the tertiary nitrogen atom is part of an aliphatic or aromatic ring and / or is bonded to at least one carbon atom that is at least secondary; and comprising at least one polyurethane catalyst (b2), the polyurethane catalyst selected from the group consisting of cyclic amides, wherein the polyurethane catalysts (b1) and (b2) do not have a dimethylamino group bonded to a primary carbon atom; (c) a blowing agent, comprising at least one physical blowing agent (c1), the physical blowing agent comprising at least one aliphatic halogenated hydrocarbon compound (c11) of general formula (1)

[0017]

[0018] wherein the group R 1 to R 4 each independently of one another represents a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or an ethyl group, and the hydrogen atoms in the methyl group or ethyl group may be wholly or partly substituted by chlorine or fluorine, provided that: the compound according to formula (1) consists of 2 to 5 carbon atoms, at least one hydrogen atom and at least two halogen atoms selected from fluorine atoms and chlorine atoms; at least one of the groups R 1 and R 4 and at least one of the groups R 2 and R 3 must have at least one halogen atom; the carbon atom of the carbon-carbon double bond carrying a methyl or ethyl group also carries a hydrogen atom; and (d) additives, if appropriate. Further, the present invention includes a method for preparing polyurethane foam, wherein this polyol component is mixed with an isocyanate component containing at least one polyisocyanate to form a reaction mixture, which is then converted into polyurethane; and includes a polyurethane foam obtained according to this method.

[0019] The polyurethanes in the sense of the present invention include all known polyisocyanate polyaddition products. These products include addition products made from isocyanates and alcohols and modified polyurethanes, which may contain isocyanurates, biurets, ureas, carbonyldiimides, iminocarbamates, biourea structures and other isocyanate addition products. Herein, polyurethane refers to polyurethane foam. The polyurethane foam of the present invention particularly includes flexible foams, semi-rigid foams, rigid foams or molded foams.

[0020] Within the scope of the present invention, polyurethane foam is understood to be foam conforming to the DIN 7726 standard. Herein, the flexible polyurethane foam of the present invention has a compressive stress or compressive strength of 15 kPa or less, preferably 1 kPa to 14 kPa, particularly 4 kPa to 14 kPa, when compressed by 10% according to the DIN 53 421 / DIN EN ISO 604 standard. The semi-rigid polyurethane foam of the present invention has a compressive stress greater than 15 kPa to less than 80 kPa when compressed by 10% according to the DIN 53 421 / DIN EN ISO 604 standard. The semi-rigid polyurethane foam and the flexible polyurethane foam of the present invention have an open-cell ratio of preferably greater than 85%, particularly preferably greater than 90%, according to DIN ISO 4590. For further details regarding the flexible polyurethane foam and the semi-rigid polyurethane foam of the present invention, see "Plastics Handbook, Volume 7, Polyurethanes", Carl Hanser Verlag, 3rd Edition, 1993, Chapter 5.

[0021] The rigid polyurethane foam of the present invention has a compressive stress of greater than or equal to 80 kPa, preferably greater than or equal to 120 kPa, particularly preferably greater than or equal to 150 kPa, when compressed by 10%. In addition, the rigid polyurethane foam of the present invention has a closed-cell density of greater than 80%, preferably greater than 90%, according to DIN ISO 4590. For further details regarding the rigid polyurethane foam of the present invention, see "Plastics Handbook, Volume 7, Polyurethanes", Carl Hanser Verlag, 3rd Edition, 1993, Chapter 6.

[0022] Within the scope of the present invention, elastic polyurethane foam is understood to be polyurethane foam according to the DIN 7726 standard, which does not have a permanent deformation exceeding 2% of its initial thickness after 10 minutes when deformed by 50% of its thickness for a short time according to the DIN 53 577 standard. Here, it can be, for example, flexible polyurethane foam.

[0023] Polyurethane molded foam is polyurethane foam according to the DIN 7726 standard, which has an outer skin or edge region with a higher density than the core density due to the molding process. Herein, the average overall original density of the core and the edge region can be in the range of 15 g / L to 800 g / L. Molded foam with a density greater than 100 g / L is generally referred to as integral foam. The polyurethane molded foam in the sense of the present invention can also be rigid polyurethane foam, semi-rigid polyurethane foam or flexible polyurethane foam. For further details regarding the integral polyurethane foam of the present invention, see "Plastics Handbook, Volume 7, Polyurethanes", Carl Hanser Verlag, 3rd Edition, 1993, Chapter 7. Preferably, the polyurethane of the present invention is polyurethane foam, particularly preferably rigid polyurethane foam, semi-rigid polyurethane foam or flexible polyurethane foam, particularly rigid polyurethane foam.

[0024] As the compound (a) reactive to isocyanate groups, compounds known in all polyurethane chemistries having groups reactive to isocyanate can be used, preferably compounds having at least one hydroxyl group, -NH group, or NH₂ group or carboxylic acid group, preferably at least one NH₂ or OH group, particularly at least one -OH group. The functionality towards isocyanate groups can be in the range of 1 to 8, preferably 2 to 8 here. These compounds reactive to isocyanate groups include polyether polyols (a1), polyester polyols (a2) or mixtures thereof, preferably polyester polyols (a2) or mixtures of polyether polyols (a1) and polyester polyols (a2). Preferably, the polyether polyols (a1) and polyester polyols (a2) have a number average molecular weight between 150 g / mol and 15,000 g / mol, preferably between 150 g / mol and 5,000 g / mol, particularly preferably between 200 g / mol and 2,000 g / mol. In addition to polyether polyols and polyester polyols, low molecular weight chain extenders and / or crosslinkers known in polyurethane chemistry can also be used, for example. Preferably, the compound (a) has a number average molecular weight of 62 g / mol to 15,000 g / mol. Preferably, the compound (a) has a number average functionality of at least 1.7, particularly preferably at least 2. According to the invention, the polyether polyols (a1) and / or polyester polyols (a2) have a number average functionality of at least 1.7, more preferably at least 2.0.

[0025] For example, the polyether polyol (a1) is prepared from epoxides (such as propylene oxide and / or ethylene oxide) or from tetrahydrofuran with starting compounds having active hydrogen (such as aliphatic alcohols, phenols, amines, carboxylic acids, water or compounds based on natural substances such as sucrose, sorbitol or mannitol) under the action of a catalyst. Mentioned here are basic catalysts or double metal cyanide catalysts, for example as described in PCT / EP2005 / 010124, EP 90444 or WO 05 / 090440.

[0026] For example, the polyester polyol (a2) is prepared from aliphatic or aromatic dicarboxylic acids and polyols, polythioether polyols, polyester amides, hydroxyl-containing polyacetals and / or hydroxyl-containing aliphatic polycarbonates, preferably in the presence of an esterification catalyst. Other possible polyols are pointed out, for example, in "Plastics Handbook, Volume 7, Polyurethanes" (3rd Edition, Carl Hanser Verlag, 1993, Section 3.1).

[0027] According to the present invention, the compound (a) reactive with isocyanate groups comprises at least one polyether polyol (a1) and / or at least one polyester polyol (a2), preferably at least one polyester polyol (a2), optionally used in combination with at least one polyether polyol (a1). Preferably, the weight fraction of the polyether polyol (a1) is herein from 0 wt% to 30 wt%, particularly preferably from 0 wt% to 20 wt%, especially from 1 wt% to 15 wt%, and the weight fraction of the polyester polyol (a2) is preferably from 70 wt% to 100 wt%, particularly preferably from 80 wt% to 100 wt%, especially from 85 wt% to 99 wt%, each based on the total weight of the polyether polyol (a1) and the polyester polyol (a2). Herein, within the scope of the present disclosure, the terms "polyester polyol" and "polyester alcohol" are synonyms, and the terms "polyether polyol" and "polyether alcohol" are also synonyms.

[0028] The polyether polyol (a1) is obtained according to known methods, for example, by anionic polymerization of alkylene oxides carried out by adding at least one starting molecule containing 1 to 8 (preferably 2 to 6) reactive hydrogen atoms or a mixture of starting molecules, each starting material of which contains on average 1.5 to 8 (preferably 2 to 6) bound reactive hydrogen atoms, in the presence of a catalyst. If a mixture of starting molecules with different functionalities is used, a non-integer functionality can be obtained. The effects on functionality, such as those caused by side reactions, are not taken into account in the nominal functionality. As the catalyst, basic hydroxides such as sodium hydroxide or potassium hydroxide, or basic alkoxides such as sodium methoxide, sodium ethoxide, potassium ethoxide or potassium isopropoxide can be used, or in cationic polymerization reactions, Lewis acids such as antimony pentachloride, boron trifluoride-ether complex or bleaching earth can also be used. Amine alcohol oxidation catalysts such as dimethylethanolamine (DMEOA), imidazole and imidazole derivatives can also be used. Further, double metal cyanide compounds can also be used as catalysts, namely the so-called DMC catalysts.

[0029] Preferably, one or more compounds having 2 to 4 carbon atoms in the alkylene group are used as the alkylene oxide, such as tetrahydrofuran, 1,2-epoxypropane, ethylene oxide, 1,2- or 2,3-epoxybutane, used alone or in the form of a mixture. Preferably, ethylene oxide and / or 1,2-epoxypropane are used, particularly preferably ethylene oxide.

[0030] Compounds containing a hydroxyl group or an amino group are considered as starting molecules, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2 - propanediol, 1,3 - propanediol, bisphenol A, bisphenol F, glycerol, trimethylolpropane, pentaerythritol, sugar derivatives (such as sucrose), hexose derivatives (such as sorbitol), methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine (TDA), naphthylamine, ethylenediamine, dimethylaniline, 2,2'-diaminodiphenylmethane (2,2 - MDA), 2,4'-diaminodiphenylmethane (2,4 - MDA), 4,4'-diaminodiphenylmethane (4,4 - MDA), diethylenetriamine, 4,4'-dimethylaniline, 1,3 - propanediamine, 1,6 - hexanediamine, ethanolamine, diethanolamine, triethanolamine and other dihydric or polyhydric alcohols or monoamine or polyamine or water. Since highly functional compounds usually exist in solid form under the conventional conditions of alcohol oxidation reaction, they are usually subjected to alcohol oxidation reaction together with a co - initiator. Suitable co - initiators are, for example, water, polyfunctional lower alcohols, such as glycerol, trimethylolpropane, pentaerythritol, diethylene glycol, ethylene glycol, propylene glycol and their homologues. Other co - initiators considered are: organic fatty acids or monofunctional fatty alcohols, fatty acid monoesters or fatty acid methyl esters, such as oleic acid, stearic acid, methyl oleate, methyl stearate or biodiesel, which are used to improve the solubility of blowing agents when preparing rigid polyurethane foam materials.

[0031] Preferred starting molecules for preparing polyether polyol (a1) are sorbitol, sucrose, ethylenediamine, TDA (triethylenetetramine), trimethylolpropane, pentaerythritol, glycerol, biodiesel, nonylphenol, ethylene glycol and diethylene glycol. Further preferred starting molecules are all starting materials or mixtures of starting materials having an average total functionality of ≤3, particularly preferably glycerol, trimethylolpropane, biodiesel, nonylphenol, ethylene glycol, diethylene glycol, propylene glycol and bisphenol A, particularly ethylene glycol, diethylene glycol and glycerol.

[0032] The polyether polyols used within the scope of component (a1) preferably have an average functionality of 1.5 to 6, particularly 2.0 to 4.0, and a number - average molecular weight preferably of 150 g / mol to 3,000 g / mol, particularly preferably 150 g / mol to 1,500 g / mol, particularly 250 g / mol to 800 g / mol. The OH value of the polyether polyols of component (a1) is preferably from 1200 mg KOH / g to 50 mg KOH / g, preferably from 600 mg KOH / g to 100 mg KOH / g, particularly from 300 mg KOH / g to 150 mg KOH / g.

[0033] Suitable polyester polyols (a2) can be prepared from organic dicarboxylic acids having 2 to 12 carbon atoms (preferably aromatic dicarboxylic acids) or mixtures of aromatic and aliphatic dicarboxylic acids and polyols (preferably diols) having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms.

[0034] Particularly contemplated as dicarboxylic acids are: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, and terephthalic acid. The dicarboxylic acids can be used individually or in admixture here. As an alternative to the free dicarboxylic acids, the corresponding dicarboxylic acid derivatives can also be used, such as dicarboxylic acid esters of alcohols having 1 to 4 carbon atoms or dicarboxylic anhydrides. As the aromatic dicarboxylic acid or its acid derivative, phthalic acid, phthalic anhydride, terephthalic acid, and / or isophthalic acid are preferably used in admixture or individually. As the aliphatic dicarboxylic acid, a mixture of dicarboxylic acids of succinic acid, glutaric acid, and adipic acid is preferably used, the mass ratio thereof being, for example, 20 to 35:35 to 50:20 to 32, and adipic acid is particularly used. Particularly preferably, only such polyester polyols are used as the polyester polyol (a2) which are obtained by using only aromatic dicarboxylic acids or their derivatives. Preferably, at least one compound selected from the group consisting of terephthalic acid, dimethyl terephthalate (DMT), polyethylene terephthalate (PET), phthalic acid, phthalic anhydride (PSA), and isophthalic acid is used here as the aromatic dicarboxylic acid, particularly preferably at least one compound selected from the group consisting of terephthalic acid, dimethyl terephthalate (DMT), polyethylene terephthalate (PET), and phthalic anhydride (PSA), and particularly selected from phthalic acid and / or phthalic anhydride.

[0035] Examples of diols and polyols, particularly diols, are: monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, polypropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerol, trimethylolpropane, and pentaerythritol, and alkoxylates of these starting materials. Monoethylene glycol, diethylene glycol, triethylene glycol, 1,2- or 1,3-propanediol, dipropylene glycol, and ethoxylates of these starting materials, such as ethoxylated glycerol, or a mixture of at least one of the above diols are preferably used. Monoethylene glycol, diethylene glycol, glycerol, and ethoxylates of these starting materials, or a mixture of at least two of the above diols, particularly diethylene glycol, are particularly used. Polyester polyols made from lactones (such as ε-caprolactone) or hydroxycarboxylic acids (such as ω-hydroxycaproic acid) can also be used.

[0036] To prepare the polyester polyol (a2), it is possible, in the absence of a catalyst or preferably in the presence of an esterification catalyst, suitably in an inert gas atmosphere such as nitrogen, in a melt at 150 °C to 280 °C, preferably 180 °C to 260 °C, and optionally under reduced pressure, to polycondense aliphatic and aromatic polycarboxylic acids and / or derivatives with polyols to the desired acid value, which is advantageously less than 10, preferably less than 2. For example, iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium, and tin catalysts in the form of metals, metal oxides, or metal salts are used as esterification catalysts. However, polycondensation can also be carried out in the liquid phase in the presence of a diluent and / or an entrainer (such as benzene, toluene, xylene, or chlorobenzene) for azeotropic distillation of the condensed water.

[0037] To prepare the polyester polyol (a2), the organic polycarboxylic acid and / or its derivative is advantageously polycondensed with the polyol in a molar ratio of 1:1 to 2.2, preferably 1:1.05 to 2.1, particularly preferably 1:1.1 to 2.0.

[0038] Generally, the obtained polyester polyol (a2) has a number average molecular weight of 200 to 3,000, preferably 300 to 1,000, particularly 400 to 800.

[0039] Preferably, the polyester polyol (a2) contains at least one polyester polyol (a2a), which is obtained by the esterification reaction of the following raw materials:

[0040] (a2a1) 10 mol% to 80 mol% of a dicarboxylic acid composition containing

[0041] (a2a11) 20 mol% to 100 mol% (based on the dicarboxylic acid composition) of one or more aromatic dicarboxylic acids or their derivatives,

[0042] (a2a12) 0 mol% to 80 mol% (based on the dicarboxylic acid composition) of one or more aliphatic dicarboxylic acids or their derivatives,

[0043] (a2a2) 0 mol% to 30 mol% of one or more fatty acids and / or fatty acid derivatives,

[0044] (a2a3) 2 mol% to 70 mol% of one or more aliphatic or cycloaliphatic diols or their alkoxylates having 2 to 18 C atoms,

[0045] (a2a4) 0 mol% to 80 mol% of the alkoxylation product of at least one starting molecule (with an average functionality of at least two),

[0046] Each based on the total amount of components (a2a1) to (a2a4), where components (a2a1) to (a2a4) add up to 100 mol%.

[0047] Preferably, the polyester polyol of component (a2) has a number average functionality of greater than or equal to 1.7, preferably greater than or equal to 1.8, particularly preferably greater than or equal to 2.0 and especially greater than 2.2, which enables the polyurethane prepared in this way to have a relatively high crosslinking density, thereby contributing to the improvement of the mechanical properties of the polyurethane foam.

[0048] Furthermore, component (a) may contain a chain extender and / or a crosslinking agent, for example, for adjusting mechanical properties such as hardness. As the chain extender and / or crosslinking agent, diols and / or triols, and amino alcohols with a molecular weight of less than 150 g / mol, preferably 60 g / mol to 130 g / mol, are used. For example, aliphatic, cycloaliphatic, and / or arylaliphatic diols having 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms, such as ethylene glycol, 1,2 - propylene glycol, diethylene glycol, dipropylene glycol, 1,3 - propylene glycol, 1,4 - butanediol, 1,6 - hexanediol, o -, m -, p - dihydroxycyclohexane, bis(2 - hydroxyethyl)hydroquinone are considered. Aliphatic and cycloaliphatic triols such as glycerol, trimethylolpropane, and 1,2,4 - and 1,3,5 - trihydroxycyclohexane are also considered.

[0049] If a chain extender, a crosslinking agent, or a mixture thereof is used in the preparation of rigid polyurethane foam materials, it is suitably added in an amount of 0 wt% to 15 wt%, preferably 0 wt% to 5 wt%, based on the total weight of component (a). Preferably, component (a) contains less than 10 wt%, particularly preferably less than 7 wt%, and especially less than 5 wt% of the chain extender and / or crosslinking agent.

[0050] Particularly, as the catalyst (b) for the preparation of polyurethane foam materials, compounds that greatly accelerate the reaction of component (a) containing reactive hydrogen atoms, especially hydroxyl groups, with polyisocyanates are used.

[0051] Suitably, an alkaline polyurethane catalyst is used, such as a tertiary amine, such as triethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N,N,N',N'-tetramethyldiamino diethyl ether, bis(dimethylaminopropyl)urea, N-methyl or N-ethylmorpholine, N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N,N-tetramethylbutanediamine, N,N,N,N-tetramethylhexanediamine-1,6, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether, dimethylpiperazine, N-dimethylaminoethylpiperidine, 1,2-dimethylimidazole, 1-azabicyclo-(2,2,0)octane, 1,4-azabicyclo-(2,2,2)octane (Dabco) and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl and N-ethyldiethanolamine, dimethylaminoethanol, 2-(N,N-dimethylaminoethoxy)ethanol, N,N',N''-tris-(dialkylaminopropyl)-s-hexahydrotriazine, such as N,N',N''-tris-(dimethylaminopropyl)-s-hexahydrotriazine and triethylenediamine. However, metal salts (such as ferrous chloride, zinc chloride, lead octoate) and tin salts (such as stannous octoate, diethyltin hexoate and dibutyltin dilaurate) as well as mixtures of tertiary amines and organotin salts are also suitable.

[0052] As catalysts, the following can also be considered: amidine compounds, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali metal hydroxides, such as sodium hydroxide and alkali alcoholates, such as sodium formate and potassium isopropoxide, alkali metal carboxylates, and alkali salts of long-chain fatty acids having 8 to 20 C atoms and optionally lateral OH groups.

[0053] In addition, embeddable amines are considered as catalysts, i.e., amines preferably having -OH, -NH or -NH2 functional groups, such as ethylenediamine, triethanolamine, diethanolamine, ethanolamine and dimethylethanolamine. The embeddable catalysts can be regarded either as compounds of component (b) or as compounds of component (a).

[0054] Additionally, catalysts for the trimerization reaction between excess NCO groups are considered: catalysts for forming isocyanurate groups, such as ammonium ions or alkali metal salts, especially ammonium or alkali metal carboxylates, alone or in combination with tertiary amines. The formation of isocyanurate leads to flame-retardant PIR foams, which are preferably used for technical rigid foams, such as insulation boards or sandwich elements used in construction.

[0055] According to the present invention, the catalyst (b) comprises at least one polyurethane catalyst (b1) which contains at least one tertiary nitrogen atom, where the tertiary nitrogen atom is part of an aliphatic or aromatic ring and / or is bonded to at least one carbon atom which is at least secondary. The catalyst (b) further comprises at least one polyurethane catalyst (b2) selected from the group consisting of cyclic amides. Here, the key point of the present invention is that the polyurethane catalysts (b1) and (b2) do not have dimethylamino groups bonded to primary carbon atoms. Within the scope of the present invention, a primary carbon atom is understood to be a carbon atom directly bonded to only another carbon atom, a secondary carbon atom is understood to be a carbon atom directly bonded to exactly two other carbon atoms, and a tertiary carbon atom is understood to be a carbon atom directly bonded to exactly three other carbon atoms.

[0056] The polyurethane catalyst (b1) preferably has at least one tertiary nitrogen atom which is directly bonded to at least one cyclic aliphatic or aromatic hydrocarbon. A preferred example is N,N-dimethylcyclohexylamine. In a preferred embodiment, the catalyst (b1) contains N,N-dimethylcyclohexylamine, and more preferably, the catalyst (b1) consists of N,N-dimethylcyclohexylamine.

[0057] The cyclic amide (b2) can be a lactam. Within the scope of the present invention, a lactam is understood to be a cyclic amide which can be substituted. Here, the amide bond is within the ring, and preferably, there is only one amide group in the ring. Examples of the lactams of the present invention are β-propiolactam, 2-pyrrolidone, N-methylpyrrolidone, γ-butyrolactam, δ-valerolactam (2-piperidone) and ε-caprolactam (ε-caprolactam).

[0058] Preferably, the cyclic amide is selected from the group consisting of at least one lactam (such as caprolactam and / or valerolactam), at least one cyclic urea or a mixture thereof, and particularly preferably, the catalyst (b2) consists of caprolactam and / or valerolactam.

[0059] In a particularly preferred embodiment, the cyclic amide (b2) contains at least one cyclic urea of general formula 2:

[0060]

[0061] wherein, -X- represents a group having 1 to 6 members, preferably 2 to 4 members, particularly preferably 3 members, and the group can be substituted. Thus, a cyclic urea structure conforming to formula 1 is produced, and the ring including the urea structure -NH-C(O)-NR- has 4 to 9 members, particularly 6 members. Preferably, the members of the group X are selected from the group consisting of -NR 1 -, -O-, -CR 2 R 3 -, -N= and -CR 4 =4 = or -N=, then the adjacent members are naturally also composed of a -CR 4 = or -N= member, thereby forming a double bond between the two members. Here, R 1 to R 4 each independently represents hydrogen, an alkylene group (preferably ethyl or methyl) or a halogen, such as a fluoro group or a chloro group. In a more particularly preferred embodiment, X represents -(CH2)3-. The group R conforming to Formula 1 represents a substituted or unsubstituted alkyl or heteroalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted alkylaryl or heteroalkylaryl group. Considered as substituents are, for example, halogen group, alkyl group, hydroxy group or amino group. In a preferred embodiment of the present invention, R contains at least one hydrogen atom reactive to isocyanate, such as -OH or -NH2 group. Preferably, R represents methyl, ethyl, propyl, pentyl, hexyl, one or more alkylene oxide units, such as oxyethylene, oxypropylene or a mixture of oxyethylene and oxypropylene, and phenyl or phenyl ether. Particularly preferably, R represents methyl, ethyl, oxyethylene, oxypropylene or phenyl methoxy ester, and more particularly preferably methyl. Also usable as the cyclic urea compound is a bridged cyclic urea structure, in which two cyclic urea structures are bridged via the group R.

[0062] In one embodiment, R has a group reactive to isocyanate, preferably a reactive group selected from terminal -OH or -NH2 groups. In another particularly preferred embodiment, it is unsubstituted.

[0063] More particularly preferably, R represents a linear, unsubstituted hydrocarbon group selected from methyl, ethyl, propyl, pentyl and hexyl, and in particular, R represents methyl.

[0064] The cyclic urea structure conforming to Formula 2 is known and has been described many times, for example in US 2013281451. The synthesis can be carried out, for example, based on N-haloalkyl-3-alkylurea, such as 1-(2-chloroethyl)-3-methylurea. These urea compounds undergo a cyclization reaction in the presence of sodium hydride. This synthesis is also described in US2013281451. Alternatively, the synthesis can be carried out based on urea and diamine, as described, for example, in EP 976796, or by the reaction of dialkyl carbonate with diamine, as described, for example, in EP 2548869.

[0065] Preferably, a catalyst combination of 0.001 to 10 parts by weight, particularly preferably 0.1 to 8 parts by weight, and particularly 0.5 to 5 parts by weight is used, based on 100 parts by weight of component (a). Preferably, the catalyst does not contain a metal catalyst and an alkali metal carboxylate. Particularly preferably, the content of catalysts (b1) and (b2), based on the total weight of catalyst (b), is at least 80% by weight, particularly preferably at least 90% by weight, more preferably at least 95% by weight, and particularly, no other amine catalysts are contained except catalysts (b1) and (b2).

[0066] The blowing agent (c) of the present invention comprises at least one physical blowing agent (c1), and the physical blowing agent includes at least one aliphatic halogenated hydrocarbon compound (c11) of the general formula (1)

[0067]

[0068] wherein the groups R 1 to R 4 each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or an ethyl group, and the hydrogen atoms in the methyl group or ethyl group may be wholly or partly replaced by chlorine or fluorine, provided that: the compound according to formula (1) consists of 2 to 5 carbon atoms, at least one hydrogen atom, and at least two halogen atoms selected from fluorine atoms and chlorine atoms; at least one of the groups R 1 and R 4 and at least one of the groups R 2 and R 3 must have at least one halogen atom; the carbon atom of the carbon-carbon double bond carrying a methyl or ethyl group also carries a hydrogen atom.

[0069] Suitable compounds (c1) include trifluoropropene and tetrafluoropropene, such as (HFO-1234), pentafluoropropene, such as (HFO-1225), chlorotrifluoropropene, such as (HFO-1233), chlorodifluoropropene and chlorotetrafluoropropene, and mixtures of one or more of these components. Particularly preferred are tetrafluoropropene, pentafluoropropene, trifluorochloropropene and hexafluorobutene, in which the unsaturated terminal carbon atom carries more than one chlorine or fluorine substituent. Examples are 1,3,3,3-tetrafluoropropene (HFO-1234ze); 1,1,3,3-tetrafluoropropene; 1,2,3,3,3-pentafluoropropene (HFO-1225ye); 1,1,1-trifluoropropene; 1,1,1,3,3-pentafluoropropene (HFO-1225zc); 1,1,1,3,3,3-hexafluorobut-2-ene; 1,1,2,3,3-pentafluoropropene (HFO-1225yc); 1,1,1,2,3-pentafluoropropene (HFO-1225yez); 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd); 1,1,1,4,4,4-hexafluorobut-2-ene, or mixtures of two or more of these components.

[0070] Particularly preferably, the aliphatic halogenated hydrocarbon compound of the general formula (1) has 3 carbon atoms and at least 4 halogen atoms. Examples of such particularly preferred compounds (c1) are hydroolefins selected from the group consisting of trans-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(E)), cis-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(Z)), trans-1,3,3,3-tetrafluoroprop-1-ene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoroprop-1-ene (HFO-1234ze(Z)) or mixtures of one or more of their components, in particular HFO 1233zd(E), 1234ze(E) or mixtures thereof.

[0071] The blowing agents used for preparing the polyurethane foam of the present invention preferably also include water, formic acid and their mixtures. These blowing agents react with isocyanate groups to form carbon dioxide, and in the case of formic acid, carbon dioxide and carbon monoxide are formed. These blowing agents release gas through chemical reactions with isocyanate groups, so they are called chemical blowing agents. In addition, physical blowing agents such as low-boiling hydrocarbons can also be used. Particularly suitable are liquids that are inert to isocyanates and have a boiling point below 100 °C, preferably below 50 °C, under atmospheric pressure and can thus evaporate under the influence of the exothermic polyaddition reaction. Examples of such preferably used liquids are aliphatic or cycloaliphatic hydrocarbons having 4 to 8 carbon atoms, such as heptane, hexane and isopentane, preferably technical mixtures of n-pentane and isopentane, n-butane and isobutane and propane, cycloalkanes such as cyclopentane and / or cyclohexane, alkenes such as furan, dimethyl ether and diethyl ether, ketones such as acetone and methyl ethyl ketone, alkyl carboxylates such as methyl formate, dimethyl oxalate and ethyl acetate, halogenated hydrocarbons such as dichloromethane, chlorodifluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane and heptafluoropropane. Mixtures of these low-boiling liquids with each other and / or with other substituted or unsubstituted hydrocarbons can also be used.

[0072] Herein, within the framework of the present invention, physical blowing agents that do not fall within the definition of (c1) are referred to as physical blowing agents (c2). Chemical blowing agents are referred to as chemical blowing agents (c3).

[0073] In addition, organic carboxylic acids such as acetic acid, oxalic acid, ricinoleic acid and compounds containing carboxyl groups are also suitable as chemical blowing agents (c3). Preferably, halogenated hydrocarbons are not used as blowing agents in addition to the compound (c1). Preferably, water, a formic acid-water mixture or formic acid is used as the chemical blowing agent (c3), and particularly preferred chemical blowing agents are water or a formic acid-water mixture.

[0074] Preferably, at least one chemical blowing agent (c3) is used in addition to the component (c1).

[0075] The amount of the blowing agent or blowing agent mixture is generally 1% to 30% by weight, preferably 1.5% to 20% by weight, particularly preferably 2.0% to 15% by weight, each based on the total of components (a) to (d). If water or a formic acid-water mixture serves as the blowing agent, it is preferably added to the polyol component in an amount of 0.2% to 6% by weight, particularly preferably 1% to 4% by weight (based on the total weight of the polyol component).

[0076] As auxiliaries and / or additives (d), for example, surface-active substances, foam stabilizers, bubble regulators, external and internal release agents, fillers, pigments, dyes, flame retardants, antistatic agents, substances for reducing aromatic amines (such as lactams), hydrolysis protectants, and substances having antifungal and antibacterial effects are used. In particular, lactams (such as ε-caprolactam) are used in combination with the cyclic ureas of the present invention conforming to formula 1, such that the aromatic amines in the polyurethane are reduced.

[0077] More information about the raw materials used can be found, for example, in "Plastics Handbook", Volume 7, Polyurethanes (edited by Günter Oertel, Carl-Hanser Verlag, Munich, 3rd edition 1993, Chapter 5, Polyurethane Flexible Foams).

[0078] The present invention also relates to a method for producing a polyurethane foam, in which a polyol component of the present invention is mixed with an isocyanate component containing at least one polyisocyanate to form a reaction mixture, which is then converted into a polyurethane foam. According to the present invention, the production of the polyurethane foam is carried out by mixing the polyol component with the isocyanate component containing the polyisocyanate to form a reaction mixture, and reacting the reaction mixture to form a polyurethane foam. Here, within the scope of the present invention, the reaction mixture refers to a mixture of an isocyanate and a compound (a) reactive with the isocyanate, the reaction conversion rate of which with respect to the isocyanate groups is less than 90%. Preferably, a two-component process is used for operation here, in which all raw materials are either contained in the isocyanate component or in the polyol component. Here, preferably, all substances capable of reacting with the isocyanate are added to the polyol component, while for those raw materials that are not reactive with the isocyanate, they can be either added to the isocyanate component or to the polyol component. Preferably, the isocyanate component contains only isocyanate.

[0079] Generally, the equivalent ratio of the NCO groups of the polyisocyanate to the total sum of reactive hydrogen atoms is 0.75 to 1.5:1, preferably 0.80 to 1.25:1. If the polyurethane contains isocyanurate groups at least partially, the ratio of the NCO groups of the polyisocyanate (a) usually used to the total sum of reactive hydrogen atoms is 1.5 to 20:1, preferably 1.5 to 8:1. A ratio of 1:1 corresponds to an isocyanate index of 100 here. If a polyurethane flexible foam is prepared, the mixing ratio is preferably selected such that the isocyanate index is preferably 50 to 95, particularly preferably 60 to 80, and particularly 65 to 75.

[0080] The preparation of the polyurethane of the present invention is preferably carried out according to the one-shot foaming method, for example by means of high-pressure or low-pressure technology. Here, the polyurethane of the present invention is prepared, for example, on a belt or preferably in a mold. Polyurethane foams can be prepared in open or closed, for example metal, forming molds.

[0081] The polyol component and the polyisocyanate component are preferably mixed in a temperature range of 15 °C to 120 °C, preferably 20 °C to 80 °C, and fed into a forming mold or a belt production line. The temperature in the forming mold is mostly in the range between 15 °C and 120 °C, preferably between 30 °C and 80 °C.

[0082] The polyisocyanates used to prepare the polyurethane of the present invention include all polyisocyanates known for the preparation of polyurethanes. These polyisocyanates include aliphatic, cycloaliphatic and aromatic divalent or polyvalent isocyanates known in the prior art, as well as mixtures thereof in any proportion. Examples are 2,2'-, 2,4'- and 4,4'-diphenylmethane diisocyanate, mixtures of diphenylmethane diisocyanate monomers and higher nuclear homologues of diphenylmethane diisocyanate (polymeric MDI), isophorone diisocyanate (IPDI) or its oligomers, 2,4- or 2,6-toluene diisocyanate (TDI) or mixtures thereof, tetramethylene diisocyanate or its oligomers, hexamethylene diisocyanate (HDI) or its oligomers, naphthalene diisocyanate (NDI) or mixtures thereof.

[0083] These polyisocyanates preferably contain toluene diisocyanate isomers (TDI isomers) and isomers of diphenylmethane diisocyanate and its higher nuclear homologues (referred to as MDI). Particularly preferably, a mixture containing 2,4'-MDI, 4,4'-MDI and higher nuclear homologues of MDI (hereinafter referred to as "polymeric MDI" or "PMDI") is used as the aromatic polyisocyanate. Further, modified isocyanates can also be used, for example, isocyanates that produce polyisocyanates by incorporating groups based on isocyanate groups. Examples of such groups are biuret groups, carbodiimide groups, uretonimine groups, isocyanurate groups, urea groups and allophanate groups. In a preferred embodiment, the content of 2,4'-diphenylmethane diisocyanate is preferably 5% by weight to 30% by weight, and the content of 4,4'-diphenylmethane diisocyanate is preferably 40% by weight to 80% by weight, each based on the total weight of the aromatic polyisocyanate (a). In a preferred embodiment, the content of the higher nuclear homologues of diphenylmethane diisocyanate is 3% by weight to 30% by weight, particularly preferably 5% by weight to 25% by weight.

[0084] Aromatic polyisocyanates can also be used in the form of prepolymers. For this purpose, the above-mentioned aromatic polyisocyanates are reacted in an excessive amount with compounds reactive to isocyanates. Here, the compounds mentioned in (a) having at least two hydrogen atoms reactive to isocyanates are preferably used as the compounds reactive to isocyanates. If isocyanate prepolymers are used as the aromatic isocyanates, they preferably have an NCO content of 16% to 31% by weight.

[0085] Finally, the present invention includes a polyurethane foam obtained by a method according to the present invention. The density of this foam according to the present invention is preferably between 10 g / L and 150 g / L, particularly preferably between 15 g / L and 100 g / L, more preferably between 20 g / L and 70 g / L, and particularly between 25 g / L and 60 g / L.

[0086] The polyol component of the present invention is characterized by improved storage stability at room temperature and elevated temperatures (e.g., 70 °C). Here, inexpensive catalysts can be used, thereby achieving reaction characteristics common in commercial systems. That is, the onset time of the reaction mixture of the present invention is preferably in the range of 10 seconds to 20 seconds, the curing time is 50 seconds to 80 seconds, and the tack-free time is 120 seconds to 200 seconds.

[0087] In particular, in the case where the isocyanate index is less than 100 and the water content is greater than 1%, a significant reduction in the concentration of aromatic amines, for example, at the surface of the polyurethane foam, can be achieved by the method of the present invention.

[0088] Hereinafter, the present invention will be illustrated by examples.

[0089] The following substances were used within the scope of this example:

[0090] Polyol 1: A polyether polyol produced from sucrose, pentaerythritol, and diethylene glycol as starting molecules and propylene oxide, having a hydroxyl value of 403 mg KOH / g

[0091] Polyol 2: A polyether polyol formed from glycerol as the starting molecule and ethylene oxide and propylene oxide, having a hydroxyl value of 158 mg KOH / g

[0092] Polyol 3: A polyether polyol formed from toluenediamine as the starting molecule and ethylene oxide and propylene oxide, having a hydroxyl value of 390 mg KOH / g

[0093] Stabilizer 1: Silica stabilizer

[0094] Blowing agent 1: Water

[0095] Blowing agent 2: 1-chloro-3,3,3-trifluoropropene (1233zd)

[0096] Catalyst 1: Bis(2-dimethylaminoethyl) ether in 30% dipropylene glycol

[0097] Catalyst 2: Dimethylcyclohexylamine

[0098] Catalyst 3: 1,3,5-Tris(dimethylaminopropyl)-hexahydro-s-triazine

[0099] Catalyst 4: ε-Caprolactam

[0100] Catalyst 5: δ-Valerolactam

[0101] Catalyst 6: 1-Methyltetrahydropyrimidin-2(1H)-one

[0102] Catalyst 7: 1,2-Dimethylimidazole in 30% diethylene glycol

[0103] Isocyanate 1: Lupranat M20 (polymeric MDI with functionality 2.7 and NCO content 31.5%; product of BASF SE).

[0104] The polyol components for these systems are listed in Table 1, and the quantities listed are in parts by weight. System 1 is the reference system, and Systems 2 to 4 are the systems of the present invention. The aim is to achieve longer storage stability than the reference system by adjusting the catalyst. In the laboratory, the following work was carried out for this purpose.

[0105] Table 1 :

[0106]

[0107]

[0108] Using a Vollrath laboratory stirrer, the configured amounts of 1000 g of polyol components consisting of polyols, stabilizers, catalysts, and blowing agents according to Table 1 were mixed. Subsequently, 200 g of each mixture was placed into 250 mL laboratory glass cups and tightly sealed. Two glass cups were stored at 23 °C and 40 °C respectively for each polyol component. The remaining polyol components were used directly for testing.

[0109] In this experimental series, the effects of storage time and storage temperature should be determined. The curing times and densities of Systems 2 to 5 were adjusted to be comparable to those of System 1. This was achieved by adjusting the catalyst dosage. The laboratory data on Day 0 was used as the initial value.

[0110] The following tests were carried out:

[0111] The polyol component according to Table 1 and the isocyanate component consisting of Isocyanate 1 were tempered to 20 ± 1 °C. The polyol component was placed in a paper cup, and the isocyanate component was weighed and added. The mixing ratio of the polyol component to the isocyanate component was 100 to 116. A Vollrath stirrer with a Lenart disk was used for mixing. The stirring speed was 1400 revolutions per minute. A stopwatch was started at the beginning of stirring. Subsequently, the curing time, needle height, non-stick time, and foam density were measured. These values are listed in Tables 2 to 6, referring to Systems 1 to 5 after preparing the polyol component and after storing for 28 days and 71 days at 23 °C and 40 °C, respectively:

[0112] Table 2, after preparation

[0113]

[0114] Table 3, stored at 23°C for 28 days

[0115]

[0116]

[0117] Table 4, stored at 23°C for 71 days

[0118]

[0119] Table 5, stored at 40°C for 28 days

[0120]

[0121] Table 6, stored at 40°C for 71 days

[0122]

[0123] The curing time was defined as the moment from the start of mixing to the process of the reaction when filaments could be pulled out of the foam material with a stick. At the same time as reaching the curing time, a needle was inserted into the foam just above the rim of the cup. After the expansion of the foam volume ended, the moving distance of the needle was measured with a ruler. In addition, the non-stick time was determined. The non-stick time was defined as the time interval from the start of stirring to when there was no longer adhesion between the foam surface and the pipette when the pipette touched the foam surface. After the foam cured, the foam crown above the rim of the cup was cut off. The content of the cup was weighed and the density was measured.

[0124] The start time and the rise time were determined by means of a foam quality assessment system (Foamat measuring instrument from Format Messtechnik GmbH). The start time was defined as the time span between the start of stirring and the start of volume expansion of the reaction mixture due to foam formation. The rise time was defined as the time span between the start of stirring and the end of volume expansion.

[0125] It is shown here that for the examples of the present invention, even after storage, the reaction parameters hardly change. In contrast, for the comparative example according to System 1, the reaction times, such as start, curing, rise and non-stick times, increase significantly and after 71 days of storage at 40 °C, no foam can even be obtained. Comparative Example 2 according to System 5, conversely, shows a very slow start time and an undesirably large needle height. In this way, strong foam expansion after curing can lead to destruction of the foam structure inside the foam.

[0126] Figure 1 The change in curing time over the storage time at 23 °C and 40 °C was again clearly illustrated in graphical form.

Claims

1. A polyol component for preparing polyurethane foam, comprising: a) a compound having at least two hydrogen atoms reactive with isocyanate, b) a catalyst, said catalyst comprising b1) at least one polyurethane catalyst (b1), said polyurethane catalyst containing at least one tertiary nitrogen atom, wherein said tertiary nitrogen atom is part of an aliphatic or aromatic ring and / or is bonded to at least one carbon atom which is at least secondary, and b2) at least one polyurethane catalyst (b2), said polyurethane catalyst selected from the group consisting of cyclic amides, wherein said polyurethane catalysts (b1) and (b2) do not have a dimethylamino group bonded to a primary carbon atom, c) a blowing agent, said blowing agent comprising at least one physical blowing agent (c1), said physical blowing agent comprising at least one aliphatic halogenated hydrocarbon compound (c11) of general formula (1) Among them, The group R 1 to R 4 each independently of one another represents a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or an ethyl group, and the hydrogen atoms in the methyl group or ethyl group can be wholly or partly replaced by chlorine or fluorine, provided that: the compound according to formula (1) consists of 2 to 5 carbon atoms, at least one hydrogen atom and at least two halogen atoms selected from fluorine atoms and chlorine atoms; the group R 1 and R 4 at least one of the groups and the group R 2 and R 3 at least one of the groups must have at least one halogen atom; The carbon atom of the carbon-carbon double bond carrying a methyl or ethyl group also carries a hydrogen atom, and d) optionally additives.

2. The polyol component according to claim 1, characterized in that The aliphatic halogenated hydrocarbon compound of general formula (1) has 3 carbon atoms and at least 4 halogen atoms.

3. The polyol component according to claim 1 or 2, characterized in that The aliphatic halogenated hydrocarbon compound of general formula (1) is HFO 1233zd(E) or 1234ze(E).

4. The polyol component according to any one of claims 1 to 3, characterized in that The polyurethane catalyst (b1) has at least one tertiary nitrogen atom directly bonded to at least one cyclic aliphatic or aromatic hydrocarbon.

5. The polyol component according to claim 4, characterized in that The polyurethane catalyst (b1) contains N,N-dimethylcyclohexylamine.

6. The polyol component according to any one of claims 1 to 5, characterized in that The cyclic amide (b2) is selected from the group consisting of caprolactam, valerolactam or at least one cyclic urea.

7. The polyol component according to any one of claims 1 to 6, characterized in that The cyclic amide (b2) is ε-caprolactam and / or valerolactam.

8. The polyol component according to any one of claims 1 to 6, characterized in that The cyclic amide (b2) is a cyclic urea of general formula 2: wherein -X- represents a substituted or unsubstituted 1- to 6-membered group, and R represents a group selected from substituted or unsubstituted alkyl or heteroalkyl groups, substituted or unsubstituted aryl groups, or substituted or unsubstituted alkylaryl or heteroalkylaryl groups.

9. The polyol component according to claim 8, characterized in that X represents -(CH2)3-.

10. The polyol component according to claim 8 or 9, characterized in that R has an -OH group or an -NH2 group.

11. The polyol component according to any one of claims 1 to 10, characterized in that No other amine catalysts are contained except the catalysts (b1) and (b2).

12. The polyol component according to any one of claims 1 to 11, characterized in that The polyol component contains water.

13. A method for preparing polyurethane foam, characterized in that, The polyol component according to any one of claims 1 to 12 is mixed with an isocyanate component containing at least one polyisocyanate to form a reaction mixture, which is then converted into the polyurethane foam.

14. A polyurethane foam obtained according to claim 13.

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