Polyester polyol and polyurethane foam system containing same

Abstract

A polyester polyol having a functionality greater than 6 is disclosed. The invention also provides a polyurethane foam system containing the polyester polyol, polyurethane foam produced by the polyurethane foam system, a composite material containing the polyurethane foam and application of the composite material.

Description

Technical Field

[0001] The present disclosure relates to a polyester polyol having a functionality greater than 6, a polyurethane system containing the polyester polyol, a polyurethane product produced by the polyurethane system and uses thereof. Background Art

[0002] Polyurethane (PU) foams are suitable for many applications, such as cushioning materials, thermal insulation materials, packaging, automotive dashboards, or building materials.

[0003] In most cases, polyurethane foams with high mechanical strength are desired. To produce such polyurethane foams, polyester polyols with high functionality are usually used in component A. Polyester polyols with high functionality are difficult to synthesize and handle because their viscosity increases significantly when the functionality increases.

[0004] CN103724598A describes a polyester polyol, which contains, by weight, 5 to 25 parts of trimellitic anhydride, 5 to 20 parts of pyromellitic dianhydride, 65 to 70 parts of recycled polyol, 2 to 5 parts of glycerol, and 0.01 to 0.025 parts of a catalyst. Summary of the invention

[0005] The object of the present disclosure is to overcome the above-mentioned problems of the prior art and to provide a polyester polyol having a hydroxyl functionality greater than 6 for producing polyurethane foam. The polyester polyol has a processable viscosity and is easy to handle.

[0006] Surprisingly, the inventors have found that the above objects can be achieved by a polyester polyol comprising the product of:

[0007] At least one selected from the group consisting of carboxylic acids containing at least three carboxylic acid groups and derivatives thereof;

[0008] a carboxyl-reactive compound containing at least two functional groups reactive toward carboxylic acid and a side chain having at least 10 carbon atoms; and

[0009] A polyhydric alcohol having at least three hydroxyl groups.

[0010] According to another aspect of the present disclosure, there is provided a polyurethane foam system comprising:

[0011] a polyol component; and

[0012] Isocyanate component,

[0013] The polyol component comprises

[0014] Polyester polyols;

[0015] one or more catalysts; and

[0016] At least one blowing agent.

[0017] In a further aspect, the present disclosure provides a polyurethane foam produced from the polyurethane foam system according to the present disclosure.

[0018] In another further aspect, the present disclosure provides a composite material comprising the polyurethane foam according to the present disclosure.

[0019] In yet another further aspect, the present disclosure provides use of the composite material as a sheet or board in a clean room or cold storage, refrigerator, roofing board, laminate; or as pipe insulation in a spray pipe or injection pipe.

[0020] It has surprisingly been found in the present application that the polyester polyols provided have a relatively low viscosity and are processable for polyurethane compositions. The polyurethane foams produced therefrom have high mechanical strength and are easy to demould. DETAILED DESCRIPTION

[0021] Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this disclosure belongs. As used herein, the following terms have the meanings ascribed to them below unless otherwise indicated.

[0022] As used herein, the articles "a" and "an" refer to one or more than one (i.e., at least one) of the grammatical object of the article. For example, "an element" means one element or more than one element.

[0023] Unless otherwise indicated, all percentages (%) are by weight.

[0024] Carboxyl refers to the carboxyl group (-C(O)OH), a functional group in organic carboxylic acids.

[0025] Unless otherwise specified, a "polyether segment" refers to any divalent segment consisting of one or more alkylene oxide repeating units. Alkylene oxides may include, but are not limited to, tetrahydrofuran, ethylene oxide, propylene oxide, butylene oxide, pentyl oxide, hexyl oxide, or phenylethylene oxide. Polyether segments include, but are not limited to, for example,

[0026] –[CH2CH2CH2CH2O] a –, –[CH2CH2O] b –, –[CH2CH(CH3)O] c –, –[CH2CH2O] d [CH2CH(CH3)O] e–, and / or any other combination of alkylene oxides, wherein a to e are independently an integer not less than 1.

[0027] Tetrahydrofuran is –CH2CH2CH2CH2O–.

[0028] Ethylene oxide (EO) is –CH2CH2O–.

[0029] Propylene oxide (PO) is –CH(CH3)CH2O– or –CH2CH(CH3)O–.

[0030] Butylene oxide (BO) is –CH(C2H5)CH2O–, –C(CH3)2CH2O–, –CH2C(CH3)2O–, –CH(CH3)CH(CH3)O–, or –CH2CH(C2H5)O–.

[0031] Pentylene oxide is –CH(C3H7)CH2O–, –CH2CH(C3H7)O–, –CH(C2H5)CH(CH3)O–, –CH(CH3)CH(C2H5)O–, –C(CH3)(C2H5)CH2O–, –CH2C(CH3)(C2H5)O–, –C(CH3)2CH(CH3)O–, or –CH2(CH3)C(CH3)2O–.

[0032] Epoxide is –CH(C4H9)CH2O–, –CH2CH(C4H9)O–, –C(C3H7)(CH3)CH2O–, –CH2C(C3H7)(CH3)O–, –CH(C3H7)CH(CH3)O, –CH(CH3)CH(C3H7)O–, –C(C2H5)(C2H5)CH2O–, –CH2C(C2H5)2O–, –CH(C2H5)CH(C2H5)O–, –C(CH3)2CH(C2H5)O–, –CH(C2H5)C(CH3)2O–, or –CH(CH3)2C(CH3)2O–.

[0033] Phenyl oxirane is –CH(C6H5)CH2O– or –CH2CH(C6H5)O–.

[0034] The hydroxyl number is defined as the mass of potassium hydroxide (KOH) (in milligrams) required to neutralize the acetic acid absorbed when one gram of a polyol or blend of polyols is acetylated.

[0035] The functionality (abbreviated as "Fn") of a polyol (including polyester polyols, polyether polyols, or other types of polyols) is defined as the number of hydroxyl groups per molecule. For a blend of several polyols, the functionality is defined as the molar average of the functionalities of all component polyols.

[0036] The isocyanate index or NCO index is defined as the ratio of the number of NCO groups present in the formulation to the number of isocyanate-reactive hydrogen atoms, given as a percentage:

[0037] Isocyanate index = [NCO] x 100 (%) / [isocyanate reactive hydrogen]

[0038] [NCO] is the number of NCO groups.

[0039] [Active hydrogen] is the number of isocyanate-reactive hydrogen atoms.

[0040] In other words, the isocyanate index expresses the percentage of isocyanate actually used in a formulation relative to the amount of isocyanate theoretically required to react with the amount of isocyanate-reactive hydrogen used in the formulation.

[0041] Unless indicated otherwise, temperature refers to room temperature and pressure refers to ambient pressure.

[0042] Unless otherwise stated, solvents are understood to mean all organic and inorganic solvents known to the person skilled in the art and do not include monomer molecules of any type.

[0043] Polyester polyols

[0044] The polyester polyols in the present disclosure have a functionality greater than 6. The polyester polyols comprise the product of:

[0045] At least one selected from the group consisting of carboxylic acids containing at least three carboxylic acid groups and derivatives thereof;

[0046] a carboxyl-reactive compound containing at least two functional groups reactive toward carboxylic acid and a side chain having at least 10 carbon atoms; and

[0047] A polyhydric alcohol having at least three hydroxyl groups.

[0048] The reaction is an esterification reaction or transesterification reaction in which the hydroxyl groups of the polyhydric alcohol and / or carboxyl-reactive compound react with the carboxylic acid.

[0049] The carboxylic acid containing at least three carboxylic acid groups may be the following carboxylic acids: trimellitic acid, trimellitic acid, pyromellitic acid, trimesic acid, pyromellitic acid, aconitic acid, propane-1,2,3-tricarboxylic acid, or any mixture thereof.

[0050] In some embodiments, the carboxylic acid is a mixture of two or more carboxylic acids.

[0051] The carboxylic acids can be used either as such, in the form of derivatives, or in the form of a mixture of one carboxylic acid, its own derivatives, and / or derivatives of another carboxylic acid species.

[0052] Derivatives of carboxylic acids are defined as:

[0053] the corresponding anhydrides in monomeric or polymeric form,

[0054] a monoalkyl ester, a dialkyl ester, a trialkyl ester, or a higher alkyl ester, preferably a mono- or di-C1-C4 alkyl ester, more preferably a monomethyl ester or a dimethyl ester or a corresponding monoethyl ester or a diethyl ester,

[0055] Monovinyl esters and divinyl esters, and also

[0056] Mixed esters, preferably mixed esters having different C1-C4 alkyl components, more preferably mixed methyl ethyl esters.

[0057] The carboxyl reactive compound contains at least two functional groups reactive to carboxylic acids and a side chain with at least 10 carbon atoms. The side chain is different from the main chain of the carboxyl reactive compound. The main chain is a chain with at least two functional groups reactive to carboxylic acids. The two functional groups may be the same or different, and both are independently selected from hydroxyl, amino or sulfhydryl (-SH) groups.

[0058] Exemplary carboxyl-reactive compounds include, but are not limited to, dialkoxylated monoalkylamines (which can be prepared as the product of a monoalkylamine and an excess of an alkoxide) or dialkoxylated monoalkylglycerols (which can be prepared as the product of a monoalkylglycerol and an excess of an alkoxide).

[0059] In some embodiments, the dialkoxylated monoalkylamine is an alkoxylated dodecylamine, an alkoxylated hexyldecylamine, or an alkoxylated octyldecylamine.

[0060] Taking N-polyoxyethylated-N-octadecylamine shown in formula (1) as an example, the main chain of the compound is a chain consisting of ethylene oxide and a central nitrogen atom, and the side chain is an octadecyl group connected to the nitrogen atom.

[0061]

[0062] In formula (1), the sum of m and n is equal to 12.

[0063] The side chain may contain at least 10 carbon atoms, preferably at least 12 carbon atoms, and more preferably at least 14 carbon atoms. The side chain may be saturated or unsaturated. The side chain may be linear, branched, or include one or more ring structures.

[0064] For preparing carboxyl terminated blowing agents, the polyhydric alcohol having at least three hydroxyl groups may include one or more triols, tetraols, pentaols or even higher polyols.

[0065] Suitable triols include triethanolamine, glycerol or trimethylolpropane, or modifications of the foregoing with a degree of alkoxylation of up to 10. Suitable tetrols include, but are not limited to, threitol, erythritol, pentaerythritol, hexane-2,3,4,5-tetraol, or modifications of the foregoing with a degree of alkoxylation of up to 10. Suitable pentaols and higher polyols include, but are not limited to, fucitol, xylitol, glucose, sorbitol, or modifications of the foregoing with a degree of alkoxylation of up to 10.

[0066] In some embodiments, the polyhydric alcohol is selected from the group consisting of diglycerol, alkoxylated diglycerol, triglycerol, alkoxylated triglycerol, erythritol, alkoxylated erythritol, pentaerythritol, alkoxylated pentaerythritol, dipentaerythritol, alkoxylated dipentaerythritol, tripentaerythritol, alkoxylated tripentaerythritol, or any mixture thereof.

[0067] When preparing polyester polyols, the stoichiometry needs to be controlled so that the carboxylic acid groups in the carboxylic acid are completely or nearly consumed during the esterification process.

[0068] In some embodiments, the molar ratio of the carboxylic acid containing at least three carboxylic acid groups to the carboxyl-reactive compound containing at least two functional groups reactive toward carboxylic acid and a side chain having at least 10 carbon atoms is between 1:1 and 3:1.

[0069] In some embodiments, the molar ratio of the carboxylic acid containing at least three carboxylic acid groups to the polyhydric alcohol having at least three hydroxyl groups is between 1:2 and 2:1.

[0070] In some embodiments, the polyester polyol has a hydroxyl value of 100 to 300 mgKOH / g.

[0071] In some embodiments, the molecular weight of the polyester polyol is 1,000 to 5,000 g / mol, preferably 1,200 to 4,000 g / mol, more preferably 1,500 to 3,500 g / mol.

[0072] In some embodiments, the viscosity of the polyester polyol is less than 35,000 mPa s at 30° C., as measured according to DIN EN 3219. Its viscosity is relatively low in view of the functionality being greater than 6. This makes the polyester polyol according to the present disclosure processable to produce polyurethane foams.

[0073] Polyurethane foam system

[0074] To prepare polyurethane foam, the polyester polyol according to the present disclosure is present in a polyurethane foam system. In various embodiments, the polyurethane foam system comprises a polyol component and an isocyanate component, wherein the polyol component comprises

[0075] Polyester polyols according to the present disclosure;

[0076] one or more catalysts; and

[0077] At least one blowing agent.

[0078] The preparation of polyurethane foams has been described elsewhere and essentially involves the reaction of a polyol and a catalyst with an isocyanate in the presence of a blowing agent.

[0079] Polyol components

[0080] The polyol component comprises a polyester polyol according to the present disclosure; one or more catalysts; and at least one blowing agent.

[0081] In some embodiments, the polyol component comprises 5 wt.% to 30 wt.%, preferably 6 wt.% to 25 wt.%, and further preferably 7 wt.% to 20 wt.% of the polyester polyol, based on the total weight of the polyol component.

[0082] In some embodiments, the polyol component further comprises one or more polyester polyols, polycarbonate polyols, or polyether polyols.

[0083] Optionally, the polyol component may further comprise a chain extender or a cross-linking agent; a flame retardant; and one or more additives and / or adjuvants.

[0084] Other polyester polyols, polycarbonate polyols and polyether polyols

[0085] In other embodiments, the polyester polyols provided in the present disclosure can be used in combination with other polyols. Other polyols include small molecule polyols, polyether polyols, polyester polyols or polycarbonate polyols.

[0086] Small molecule polyols include, but are not limited to, ethylene glycol, diethylene glycol, dipropylene glycol, glycerol, pentaerythritol, sucrose, and the like.

[0087] Polyester polyols, polycarbonate polyols and polyether polyols are collectively referred to as polyols. Polyols refer to polyols. Preferably, polyols having a functionality of 2 to 8, more preferably 3 to 6, and a hydroxyl number of 150 to 850 mg KOH / g, more preferably 200 to 600 mg KOH / g are examples of higher molecular weight compounds having at least two reactive hydrogen atoms.

[0088] For example, polythioether polyol, polyester amide, hydroxyl-containing polyacetal, hydroxyl-containing aliphatic polycarbonate, and preferably, polyester polyol and polyether polyol. In addition, a mixture of at least two of the above polyhydroxy compounds may be used as long as these compounds have an average hydroxyl value within the above range.

[0089] Suitable polyester polyols can be produced, for example, by organic dicarboxylic acids with 2 to 12 carbons, preferably aliphatic dicarboxylic acids with 4 to 6 carbons and polyvalent alcohols with 2 to 12 carbons, preferably 2 to 6 carbons, preferably glycols. The example of dicarboxylic acids includes succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. Dicarboxylic acids can be used individually or in mixtures. Except free dicarboxylic acids, corresponding dicarboxylic acid derivatives can also be used, such as dicarboxylic acid monoesters or diesters of alcohols with 1 to 4 carbons, or dicarboxylic anhydrides. Succinic acid, glutaric acid and adipic acid are preferred with a dicarboxylic acid mixture of the amount ratio of 20-35:35-50:20-32 weight portions, especially adipic acid. Examples of divalent and polyvalent alcohols, especially diols, include ethylene glycol, diethylene glycol, 1,2- and 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerol and trimethylolpropane. Ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or a mixture of at least two of these diols is preferred, especially a mixture of 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol.

[0090] Polyester polyols can be produced by polycondensation of organic polycarboxylic acids (e.g., aromatic or preferably aliphatic polycarboxylic acids and / or derivatives thereof) and polyvalent alcohols in the absence of a catalyst or preferably in the presence of an esterification catalyst, preferably in an atmosphere of an inert gas (e.g., nitrogen, carbon dioxide, helium, argon, etc.), at a temperature of 150° C. to 250° C., preferably 180° C. to 220° C., optionally under reduced pressure to a desired degree of polymerization, preferably less than 10, especially less than 5. In a preferred embodiment, the esterification mixture is polycondensed at the above temperature to an acid value of 80 to 30, preferably 40 to 30, the polycondensation being carried out at normal pressure and then at a pressure of less than 500 mbar, preferably 50 to 150 mbar. Examples of suitable esterification catalysts include iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycondensation can also be carried out in the liquid phase in the presence of diluents and / or entrainers, such as benzene, toluene, xylene or chlorobenzene, for azeotropic distillation of the condensation water.

[0091] To produce the polyester polyol, the organic polycarboxylic acid and / or its derivatives are polycondensed with the polyvalent alcohol preferably in a molar ratio of 1:1-1.8, preferably 1:1.05-1.2.

[0092] The resulting polyester polyols preferably have a functionality of 2 to 3 and a hydroxyl number of 150 to 500 and in particular 200 to 400.

[0093] Polyether polyols which can be obtained by known methods can also be used as polyols. For example, polyether polyols can be produced by anionic polymerization using an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an alkali metal alcoholate such as sodium methoxide, sodium ethoxide or potassium ethoxide or potassium isopropoxide as a catalyst and adding at least one initiator molecule containing 2 to 8, preferably 3 to 8 active hydrogens, or by cationic polymerization using a Lewis acid such as antimony pentachloride, boron trifluoride etherate, etc., or bleaching earth derived from one or more alkylene oxides having 2 to 4 carbons in the alkylene group as a catalyst.

[0094] Suitable cyclic ethers and alkylene oxides include, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- and 2,3-butylene oxide, phenylethylene oxide and preferably ethylene oxide and 1,2-propylene oxide. The alkylene cyclic ethers and oxides can be used individually, alternately, one after the other or as a mixture. Examples of suitable initiators include water, polyvalent alcohols, aliphatic and aromatic organic dicarboxylic acids (such as succinic acid, adipic acid, phthalic acid and terephthalic acid), optionally N-mono-, N,N- and N,N'-dialkyl substituted diamines (having 1 to 4 carbons in the alkyl group), such as optionally mono- and dialkyl substituted ethylenediamine, diethylenetriamine, triethylenetetramine, 1,3-propylenediamine, 1,3- and 1,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexamethylenediamine, phenylenediamine, 2,3-, 2,4- and 2,6-toluenediamine and 4,4'-, 2,4'- and 2,2'-diaminodiphenylmethane.

[0095] Polyvalent alcohols, especially divalent, trivalent and / or tetravalent alcohols are preferred, such as ethylene glycol, 1,2- and 1,3-propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane, erythritol, pentaerythritol, sorbitol and sucrose.

[0096] Suitable initiators also include alkanolamines such as ethanolamine, diethanolamine, N-methyl- and N-ethylethanolamine, N-methyl- and N-ethyldiethanolamine and triethanolamine plus ammonia.

[0097] The polyether polyols have a functionality of preferably 3 to 8 and in particular 3 to 6 and a hydroxyl number of 300 to 850, preferably 350 to 800.

[0098] Also suitable as polyether polyols are melamine polyether polyol dispersions according to U.S. Pat. No. 4,293,657; polymer polyether polyol dispersions prepared from polyepoxides and epoxy resin hardeners in the presence of polyether polyols according to U.S. Pat. No. 4,305,861; dispersions of aromatic polyesters in polyols according to U.S. Pat. No. 4,435,537; dispersions of organic and / or inorganic fillers in polyols according to U.S. Pat. No. 4,243,755; polyurea polyether polyol dispersions according to DE A 31 2 402, tris-(hydroxyalkyl)isocyanurate polyether polyol dispersions according to U.S. Pat. No. 4,514,526 and microcrystalline suspensions according to U.S. Pat. No. 4,560,708, the details of which are considered part of the present patent disclosure and are incorporated herein by reference.

[0099] Like polyester polyols, polyether polyols can be used alone or in the form of a mixture. In addition, they can be mixed with the above-mentioned dispersions, suspensions, or polyester polyols and hydroxyl-containing polyesteramides, polyacetals and / or polycarbonates.

[0100] Examples of hydroxyl-containing polyacetals that can be used include, for example, compounds that can be produced from glycols such as diethylene glycol, triethylene glycol, 4,4'-dihydroxyethoxydiphenyldimethylmethane, hexanediol, and formaldehyde. Suitable polyacetals can also be produced by polymerization of cyclic acetals.

[0101] Suitable hydroxyl-containing polycarbonates include those of known type, such as those obtained by reaction of a diol (eg, 1,3-propylene glycol, 1,4-butanediol and / or 1,6-hexanediol, diethylene glycol, triethylene glycol or tetraethylene glycol) and a diaryl carbonate (eg, diphenyl carbonate) or phosgene.

[0102] Polyesteramides include predominantly linear condensates of polyvalent saturated and / or unsaturated carboxylic acids and their anhydrides with amino alcohols, or mixtures of polyvalent alcohols and amino alcohols and / or polyamines.

[0103] catalyst

[0104] The catalyst used in the present disclosure may include one or more selected from metal-based catalysts and amine-based catalysts. The catalyst can greatly accelerate the reaction of the hydroxyl-containing compound in the components and optionally with the polyisocyanate.

[0105] The metal-based catalyst may include an organic tin compound, such as a tin (II) salt of an organic carboxylic acid, for example, tin (II) acetate, tin (II) octoate, tin (II) ethylhexanoate, and tin (II) laurate, and a dialkyltin (IV) salt of an organic carboxylic acid, for example, dibutyltin diacetate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate. The metal-based catalyst may include a potassium compound selected from the group consisting of potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium benzoate, potassium formate, potassium acetate, potassium propionate, potassium butyrate, potassium valerate, potassium hexanoate, potassium octoate, potassium 2-ethylhexanoate, potassium neodecanoate, potassium decanoate, potassium salicylate, potassium laurate, potassium oleate, potassium maleate, potassium citrate, potassium oxalate, potassium methoxide, potassium cellulose, potassium carboxymethylcellulose, potassium hyaluronate, potassium alginate, potassium gluconate, and any combination thereof.

[0106] Examples of amine-based catalysts can include amines such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, N-cyclohexylmorpholine, N,N,N'N'-tetramethylethylenediamine, N,N,N',N'-tetramethylbutylenediamine or -hexanediamine, pentamethyldiethylenetriamine, tetramethyldiaminoethyl ether, bis(dimethylaminopropyl)urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo[3.3.0]octane and preferably 1,4-diaza-bicyclo[2.2.-2]octane, and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine and dimethylethanolamine.

[0107] Suitable catalysts include tris-(dialkylamino-s-hexahydrotriazines, especially tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali metal hydroxides such as sodium hydroxide and alkali metal alcoholates such as sodium methoxide and potassium isopropoxide, and alkali metal salts of long-chain fatty acids having 10 to 20 carbon atoms and optionally OH side groups. A person skilled in the art can select a specific catalyst or combination of catalysts.

[0108] Foaming agent

[0109] The blowing agents which can be used are physical blowing agents and chemical blowing agents.

[0110] Compounds known as physical blowing agents can also be used preferably in combination with water or preferably instead of water. These are compounds which are inert relative to the starting components, are predominantly liquid at room temperature, and evaporate under the conditions of the urethane reaction. The boiling point of these compounds is preferably below 500° C. Among the physical blowing agents there are also compounds which are gaseous at room temperature and are introduced or dissolved into the starting components under pressure, examples being carbon dioxide, low-boiling alkanes and fluoroalkanes.

[0111] The physical blowing agents are selected primarily from the group consisting of alkanes and / or cycloalkanes having at least 4 carbon atoms, dialkyl ethers, esters, ketones, acetals, fluoroalkanes having 1 to 8 carbon atoms, and tetraalkylsilanes having 1 to 3 carbon atoms in the alkyl chain, in particular tetramethylsilane. Examples which may be mentioned are propane, n-butane, isobutane, cyclobutane, n-pentane, isopentane, cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone, and also fluoroalkanes which are degradable in the troposphere and therefore do not damage the ozone layer, for example trifluoromethane, difluoromethane, 1,1,1,3,3-pentafluorobutane, 1,1,1,3,3-pentafluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane and heptafluoropropane. The physical blowing agents mentioned can be used alone or in any desired combination with one another.

[0112] Chemical blowing agents include water, carboxylic acids (such as formic acid) and / or carboxyl-terminated oligomers, which react with isocyanate groups to eliminate carbon dioxide and, respectively, carbon dioxide and carbon monoxide.

[0113] The amount of blowing agent is 1 to 55% by weight, preferably 1 to 40% by weight, particularly preferably 2 to 30% by weight and in particular 5 to 25% by weight, based on the total weight of the polyol component.

[0114] In some embodiments, the amount of water is preferably in the range of 0.1% to 5.0% by weight based on the weight of the polyol component.

[0115] Chain Extenders and Crosslinkers

[0116] Polyurethane foams can be prepared with or without chain extenders and / or crosslinkers. Suitable chain extenders and / or crosslinkers preferably include alkanolamines, more preferably diols and / or triols. Typical examples are alkanolamines, such as ethanolamine and / or isopropanolamine; dialkanolamines, such as diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, diisopropanolamine; trialkanolamines, such as triethanolamine, triisopropanolamine; and addition products from ethylene oxide or 1,2-propylene oxide; and alkylenediamines having 2 to 6 carbon atoms in the alkylene group, such as N,N'-tetrakis(2-hydroxyethyl)-ethylenediamine and N,N'-tetrakis(2-hydroxypropyl)ethylenediamine; aliphatic, cycloaliphatic and / or aromatic aliphatic diols having 2 to 14, more preferably 4 to 10 carbon atoms, such as ethylene. diols, 1,3-propylene glycol, 1,10-decanediol, o-, m-, p-dihydroxycyclohexanes, diethylene glycol, dipropylene glycol, and preferably 1,4-butanediol, 1,6-hexanediol and bis(2-hydroxyethyl)hydroquinone; triols, such as 1,2,4- and 1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane; and lower molecular weight hydroxyl-containing polyalkylene oxides (based on ethylene oxide and / or 1,2-propylene oxide), and aromatic diamines such as toluenediamine and / or diaminodiphenylmethane, as well as the above-mentioned alkanolamines, diols and / or triols as initiator molecules.

[0117] If chain extenders, crosslinkers or mixtures thereof are used in the preparation of the polyurethane foam, these are advantageously used in amounts of up to 20 wt.%, more preferably 2 to 10 wt.%, based on the weight of the polyol component.

[0118] Flame retardants

[0119] The polyol component may optionally contain a flame retardant. The flame retardant includes at least one phosphorus-containing flame retardant that is a derivative of phosphoric acid, polyphosphoric acid, phosphonic acid, and / or phosphinic acid.

[0120] Suitable flame retardants for the purposes of the present disclosure are preferably liquid organophosphorus compounds, such as halogen-free organophosphates, such as triethyl phosphate (TEP); halogenated phosphates, such as tris (1-chloro-2-propyl) phosphate (TCPP) and tris (2-chloroethyl) phosphate (TCEP); and organic phosphonates, such as dimethyl methylphosphonate (DMMP), dimethyl propanephosphonate (DMPP); or solids, such as ammonium polyphosphate (APP) and red phosphorus. In addition, in addition to phosphorus-containing flame retardants, halogenated compounds (such as halogenated polyols) and solids (such as expanded graphite and melamine) are also suitable as auxiliary flame retardants.

[0121] Other additives and auxiliaries

[0122] Optionally, other additives and / or adjuvants may be incorporated into the polyol component to produce the polyurethane foam. Examples include surfactants, foam stabilizers, cell regulators, fillers, dyes, pigments, hydrolysis inhibitors, fungistats and bacteriostats.

[0123] Examples of suitable surfactants are compounds that are used to support the homogenization of the starting material and can also adjust the cell structure of the plastic. Specific examples are salts of sulfonic acids, for example, alkali metal salts or ammonium salts of fatty acids (such as oleic acid or stearic acid), dodecylbenzenesulfonic acid or dinaphthylmethanedisulfonic acid and ricinoleic acid; foam stabilizers, such as siloxane-oxyalkylene copolymers and other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, castor oil esters, ricinoleic acid esters, Turkey red oil and peanut oil; and cell regulators, such as paraffin, fatty alcohols and dimethylpolysiloxane. Surfactants are usually used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the polyol component. In addition, oligoacrylates with polyoxyalkylene and fluoroalkane side groups are also suitable for improving emulsification effects, cell structure and / or stabilizing foam. These surfactants are usually used in an amount of 0.01wt.% to 5wt.% based on the weight of the polyol component. For example, fillers are conventional organic and inorganic fillers and reinforcing agents. Specific examples are inorganic fillers, such as silicate minerals, for example, phyllosilicates such as antigorite, serpentine, hornblende, amphibole, chrysotile and talc; Metal oxides such as kaolin, aluminum oxide, titanium oxide and iron oxide; Metal salts such as chalk, barite and inorganic pigments such as cadmium sulfide, zinc sulfide and glass, etc.; Kaolin (china clay), aluminum silicate, and coprecipitates of barium sulfate and aluminum silicate, and natural and synthetic fiber minerals such as wollastonite, metals and glass fibers of various lengths. Examples of suitable organic fillers are carbon black, melamine, rosin, cyclopentadiene-based resins, cellulose fibers, polyamide fibers, polyacrylonitrile fibers, polyurethane fibers, and polyester fibers based on aromatic and / or aliphatic dicarboxylic acid esters, and in particular carbon fibers. Inorganic and organic fillers can be used alone or as a mixture, and can be introduced into the polyol component or the isocyanate side in an amount of 0.5 to 40 weight percent based on the weight of the components (polyols and isocyanates).

[0124] Isocyanate component

[0125] The isocyanate component in the present disclosure comprises one or more selected from the group consisting of aliphatic, alicyclic, araliphatic and aromatic isocyanates. For example, the isocyanate component may comprise an alkylene diisocyanate having 4 to 12 carbons in the alkylene group, such as 1,12-dodecane diisocyanate, 2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, 1,4-tetramethylene diisocyanate and preferably 1,6-hexamethylene diisocyanate; alicyclic diisocyanates, such as 1,3- and 1,4-cyclohexane diisocyanate and any mixture of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate), 2,4- and 2,6-hexamethylcyclohexane diisocyanate. Hydrogen toluene diisocyanate and the corresponding isomer mixtures, 4,4'-2,2'- and 2,4'-dicyclohexylmethane diisocyanate and the corresponding isomer mixtures, and preferably aromatic diisocyanates and polyisocyanates such as 2,4- and 2,6-toluene diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and the corresponding isomer mixtures, 4,4'- and 2,4'-diphenylmethane diisocyanate and the corresponding isomer mixtures, 4,4'- and 2,4'-diphenylmethane diisocyanate and a mixture of polyphenylene polymethylene polyisocyanate (polymeric MDI), and a mixture of polymeric MDI and toluene diisocyanate. Organic diisocyanates and polyisocyanates can be used alone or in the form of a mixture. Preferably, the isocyanate component contains a percentage of not less than 90wt.% of monomeric and / or polymeric methylene diphenyl diisocyanate.

[0126] The polyurethane foam of the present disclosure can be prepared by conventional mixing equipment. The method comprises: providing a polyol component; providing an isocyanate component; and reacting the polyol component and the isocyanate component in a weight ratio such that the isocyanate index is 100 to 500, preferably 110 to 450, more preferably 110 to 150.

[0127] It should be observed that the isocyanate index as used herein is considered from the perspective of the actual foaming process involving isocyanate components and isocyanate-reactive components. Any isocyanate groups consumed in a preliminary step to produce a modified polyisocyanate (including such isocyanate derivatives known in the art as prepolymers) or any active hydrogens consumed in a preliminary step (e.g., reacted with an isocyanate to produce a modified polyol or polyamine) are not considered in the calculation of the isocyanate index. Only free isocyanate groups and free isocyanate-reactive hydrogens (including those of water) present in the actual foaming process are considered.

[0128] application

[0129] The polyurethane foam according to the present disclosure may be included in a composite material. The composite material may be a sandwich panel. The sandwich panel may include the polyurethane foam as its core layer. The sandwich panel may include a metal layer as an outer layer.

[0130] Composite materials can be used in various areas such as as sheets or boards in cleanrooms or cold rooms, freezers, roofing panels, laminates or insulation board applications or as pipe insulation in spray pipe applications and injection pipe areas.

[0131] Examples

[0132] Measurement and test methods

[0133] The measurement and test methods are shown in Table 1.

[0134] Table 1 Measurement and test standards

[0135] characteristic unit Test Standards Compression strength <![CDATA[N / mm 2 ]]> ISO 844:2014 Demolding thickness mm BASF's own procedures Viscosity mPa s DIN EN 3219

[0136] The demoulding thickness (releasability) was determined by measuring the demoulding thickness of the post-expansion foam produced using a 70×40×9 cm box mold at a mold temperature of 45° C.±2° C. and a demoulding time of 3.5 min. The overfilling was 14.5%, i.e. 14.5% more reaction mixture was used than was required for complete foaming of the mold. The post-expansion describes the expansion of the foam block (in mm). The poor demoulding properties are clearly visible by the significant post-expansion of the rigid PU foam, as shown by the demoulding thickness of significantly more than 90 mm.

[0137] Material

[0138] The materials used in the examples are as follows.

[0139] Polyol 1, a polyether polyol (PO-based), has a molecular weight of about 1100, an OH value of 110 mg KOH / g and a functionality of 2.

[0140] NJ4502, a sucrose-based polyether polyol from Jurong Ningwu New Material Development Co., Ltd., with an OH value of 450 mg KOH / g and a functionality of 5.1.

[0141] Polydo PN 560, a propylene oxide based pentaerythritol initiated polyol from Kukdo Chemical, has an average molecular weight of 400 g / mol, an OH value of 560 mg KOH / g and a functionality of 4.

[0142] AC1812, N-polyoxyethylated-N-octadecylamine from Shanghai Jiahua Company Limited, CAS No. 26635-92-7, molecular weight 801 and functionality 2.

[0143] AC1210, N-polyoxyethylated-N-dodecylamine from Shanghai Jiahua Co., Ltd., CAS No. 26635-75-6, molecular weight of 645 and functionality of 2.

[0144] Trimellitic acid, also known as 1,2,4-benzenetricarboxylic acid, was obtained from Shanghai Guoyao Company Limited, CAS No. 528-44-9.

[0145] 1,2,4-Benzenetricarboxylic anhydride, from Shanghai Sinopharm Co., Ltd., CAS No. 552-30-7.

[0146] Trimesic acid, also known as 1,3,5-benzenetricarboxylic acid, was obtained from Shanghai Sinopharm Co., Ltd., CAS No. 554-95-0.

[0147] Cyclopentane, also known as "c-pentane", is from BASF, CAS number 287-92-3.

[0148] PMDI, 4,4'-diphenylmethane diisocyanate (MDI) containing high-functionality oligomers and isomers, from BASF.

[0149] Niax Silicone L6900 Copolymer from Momentive Performance Materials GmbH is a foam stabilizer used in the manufacture of rigid polyurethane foams.

[0150] BL-11, a 70% solution of bis(dimethylaminoethyl) ether in dipropylene glycol from Evonik, CAS No. 59948-21-9, was used as catalyst.

[0151] 8. N,N-Dimethylcyclohexylamine, CAS No. 98-94-2, from Evonik, was used as a catalyst.

[0152] TMR-2, 2-hydroxypropyltrimethylammonium formate from Evonik, CAS No. 62314-25-4, was used as catalyst.

[0153] Synthesis of polyester polyols

[0154] The chemical route to synthesize this chemical is the esterification of a mixture of 1,3,5-benzenetricarboxylic acid and two polyhydric alcohols. The synthesis can follow a stepwise approach or a one-pot process.

[0155] In the stepwise method, 1,3,5-benzenetricarboxylic acid is first mixed with a dihydric alcohol and heated. The reaction is catalyzed by 0.03wt.% TTB based on the total weight of the acid and the dihydric alcohol. The reactor is equipped with a Vigreux column and a Dean-Stark type condenser to collect the condensed product. During the first half of the synthesis, the device is continuously purged with nitrogen to limit oxidation and promote the transport of water vapor. While stirring, the mixture is heated to 120°C using a heating jacket. The catalyst is added when the temperature of the mixture reaches 120°C. The reaction temperature is gradually increased to keep the by-products formed from being distilled. After 8h at 230°C, the product is cooled to 60°C. In the second step, PN560 is added to the mixture. Following the same protocol and after the final product is cooled to room temperature, it is discharged from the reactor.

[0156] In the one-pot process, all reactants are mixed and heated at the beginning. The synthesis is carried out according to the same scheme as for the first step in the stepwise process.

[0157] After synthesis, the OH value and viscosity value were measured. The OH value was determined by titration. The viscosity value was tested at 30° C., except for the polyester polyol in Comparative Example 2 due to its very high viscosity. The polyester polyol was heated to 35° C. to reduce its viscosity to a range measurable by the viscometer.

[0158] Table 2 Raw materials and properties of synthesized polyester polyols

[0159]

[0160]

[0161] The formulations of polyurethane foam systems with polyester polyols synthesized in Comparative Examples 1 and 2 and Examples 1 to 4 are shown in Table 3. From the comparison, it can be inferred that any of Examples 1 to 4 has a comparable or even lower viscosity at 30°C compared to Comparative Examples 1 or 2 despite similar functionality. By using AC1812 or AC1210 in the raw materials, the resulting polyester polyols have an operable viscosity at 30°C. The presence of side chains on nitrogen atoms can help to reduce viscosity. In addition, considering the similar raw materials between Comparative Examples 1 and 2, the viscosity increases significantly when the functionality increases. Example 4, which has a shortened side chain of 12 carbon atoms, has a slightly higher viscosity than the long side chain of 18 carbon atoms in Example 3.

[0162] These six formulations were used to prepare box-type mold foams with dimensions of 40 cm*40 cm*9 cm. During the reaction, the temperature in the mold was controlled at 50° C. 30 minutes after the foam was injected into the mold, the cured foam was demoulded. The properties of the foam are listed in Table 3.

[0163] Table 3 Formulation and properties of polyurethane foam system

[0164]

[0165]

[0166] As can be seen from Table 3, the formulations with the polyester polyols synthesized in Examples 1 to 4 exhibited compressive strength comparable to that of the other high-functionality polyester polyols in Comparative Example 1. The demoldability of the resulting polyurethane foam was also maintained or improved. The polyester polyol synthesized in Comparative Example 2 was too viscous, and the foaming test failed due to difficulty in blending the polyol component and the isocyanate component.

Claims

1. A polyester polyol having a functionality greater than 6, comprising the product of: At least one selected from the group consisting of carboxylic acids containing at least three carboxylic acid groups and derivatives thereof; a carboxyl-reactive compound containing at least two functional groups reactive toward the carboxylic acid and a side chain having at least 10 carbon atoms; and A polyhydric alcohol having at least three hydroxyl groups.

2. The polyester polyol according to claim 1, wherein The carboxylic acid is trimellitic acid, trimellitic acid, pyromellitic acid, pyromellitic acid, aconitic acid, citric acid, isocitric acid, aconitic acid, propane-1,2,3-tricarboxylic acid, or any mixture thereof.

3. The polyester polyol according to claim 1, wherein The carboxyl-reactive compound is a dialkoxylated monoalkylamine or a dialkoxylated monoalkylglycerol.

4. The polyester polyol according to claim 3, wherein The dialkoxylated monoalkylamine is alkoxylated dodecylamine, alkoxylated hexyldecylamine or alkoxylated octyldecylamine.

5. The polyester polyol according to claim 1, wherein The polyhydric alcohol is selected from the group consisting of diglycerol, alkoxylated diglycerol, triglycerol, alkoxylated triglycerol, erythritol, alkoxylated erythritol, pentaerythritol, alkoxylated pentaerythritol, dipentaerythritol, alkoxylated dipentaerythritol, tripentaerythritol, alkoxylated tripentaerythritol, or any mixture thereof.

6. The polyester polyol according to claim 1, wherein The polyester polyol has a hydroxyl value of 100 to 300 mgKOH / g.

7. The polyester polyol according to any one of claims 1 to 5, wherein The molecular weight of the polyester polyol is 1,000 to 5,000 g / mol, preferably 1,200 to 4,000 g / mol, more preferably 1,500 to 3,500 g / mol.

8. The polyester polyol according to any one of claims 1 to 5, wherein The polyester polyol has a viscosity of less than 35,000 mPa s at 30° C., as measured according to DIN EN 3219.

9. A polyurethane foam system comprising: a polyol component; and Isocyanate component, The polyol component comprises The polyester polyol according to any one of claims 1 to 7; one or more catalysts; and At least one blowing agent.

10. The polyurethane foam system according to claim 8, wherein The polyester polyol has a weight percentage of 5 wt.% to 30 wt.%, preferably 6 wt.% to 25 wt.%, more preferably 7 wt.% to 20 wt.%, based on the total weight of the polyol component.

11. The polyurethane foam system according to claim 8, wherein The isocyanate component comprises one or more selected from the group consisting of aliphatic, cycloaliphatic, araliphatic and aromatic isocyanates.

12. The polyurethane foam system according to claim 10, wherein: The isocyanate component contains monomeric and / or polymeric methylene diphenyl diisocyanate in a percentage of not less than 90 wt.%.

13. The polyurethane foam system according to claim 8, wherein These catalysts include one or more selected from metal-based catalysts and amine-based catalysts.

14. The polyurethane foam system according to claim 8, wherein: The weight ratio of the polyol component and the isocyanate component is such that the isocyanate index is 100 to 500, preferably 110 to 450, more preferably 110 to 150.

15. A polyurethane foam produced from the polyurethane foam system according to any one of claims 8 to 13.

16. A composite material comprising the polyurethane foam according to claim 14.

17. The composite material according to claim 15, wherein The composite material comprises the polyurethane foam as a core layer.

18. Use of the composite material according to claim 15 or 16 as a plate or board in a clean room or cold storage, refrigerator, roofing board, laminate; or as pipe insulation in a spray pipe or injection pipe.

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