Bio-based polyester polyol and polyurethane foam system comprising same

Abstract

In one aspect, a polyester polyol comprises the condensation product of a bio-based C7-C12 dicarboxylic acid, a bio-based C2-C10 diol, and a branched diol of formula (I) wherein R1 and R2 are independently linear alkylene bonds having 1 to 3 carbon atoms, and R3 and R4 are independently alkyl groups having 1 to 3 carbon atoms, and wherein the weight ratio of the bio-based C2-C10 diol to the branched diol is (25 to 53) to (47 to 75). The invention also provides a polyurethane system containing the polyester polyol and a method for preparing the polyester polyol. # imgabs0 #

Description

Technical Field

[0001] The present disclosure relates to a bio - based polyester polyol, a polyurethane system comprising the bio - based polyester polyol, and a method for preparing the same. Background Art

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

[0003] In most cases, polyurethane foams with good properties such as hydrolysis resistance and mechanical strength are required. At the same time, due to sustainability requirements, polymers are increasingly expected to be bio - based.

[0004] CN112142960A describes a hydrophobic polyester polyol and a polyurethane elastomer based on the hydrophobic polyester polyol. The polyester polyol is prepared by polymerizing long - chain diacids and diols. The diol is a branched diol or a mixture of a branched diol and a straight - chain diol.

[0005] CN109180915A discloses a liquid polyester polyol for polyurethane coatings, which is based on raw materials of a mixture of diacids and a mixture of small - molecule diols. The mixture of diacids is a mixture of by - products of adipic acid production.

[0006] Bio - based raw materials for polyurethane production include castor oil, bio - based poly(tetrahydrofuran ether) (bio - based pTHF), and bio - based polyester polyols. Generally, the dosage of castor oil in the polyol component cannot be high, otherwise the curing of the polyurethane system and the cold flexure or adhesion strength of the resulting polyurethane product will be poor. Bio - based pTHF is very expensive and scarce in the market. In addition, high contents of commercially available bio - based polyester polyols usually result in poor hydrolysis properties of polyurethanes, which limits the applications of the products. Summary of the Invention

[0007] The object of the present disclosure is to provide a bio - based polyester polyol for producing polyurethane foams. The polyester polyol is based on bio - based diols and bio - based diacids and provides an alternative to traditional petroleum - based polyester polyols. The bio - based content of the polyester polyol is very high.

[0008] Surprisingly, it has been found that the above object can be achieved by a polyester polyol comprising the product of:

[0009] Bio - based C7 - C12 dicarboxylic acids;

[0010] Bio - based C2 - C10 diols; and

[0011] A branched diol having the following formula:

[0012]

[0013] Wherein R1 and R2 are independently a straight-chain alkylene bond having 1 to 3 carbon atoms, and R3 and R4 are independently an alkyl group having 1 to 3 carbon atoms, and wherein the weight ratio of the biobased C2-C10 diol to the branched diol is (25-53) to (47-75).

[0014] According to another aspect of the present disclosure, there is provided a polyurethane system comprising:

[0015] a polyol component; and

[0016] an isocyanate component,

[0017] wherein the polyol component comprises

[0018] a polyester polyol; and

[0019] one or more catalysts.

[0020] According to another aspect of the present disclosure, there is provided a method for preparing a polyester polyol, the method comprising:

[0021] In a reaction vessel, mixing a biobased C7-C12 dicarboxylic acid, a biobased C2-C10 diol, and a branched diol, and obtaining a mixture;

[0022] Heating the mixture at a first temperature in the range of 180 °C to 250 °C for a first duration;

[0023] Heating the crude product at a second temperature in the range of 100 °C to 150 °C for a second duration in the range of 1 hour to 4 hours; and

[0024] Separating the polyester polyol from the crude product after step (c), wherein the branched diol has the following formula:

[0025]

[0026] R1 and R2 are independently a straight-chain alkylene bond having 1 to 3 carbon atoms, and R3 and R4 are independently an alkyl group having 1 to 3 carbon atoms.

[0027] It has been surprisingly found in this application that the provided polyester polyol can be processed for use in polyurethane compositions. The polyurethane foam produced therefrom has high mechanical strength and aging resistance. Detailed Description

[0028] Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this disclosure pertains. As used herein, unless otherwise specified, the following terms have the meanings given to them below.

[0029] As used herein, the article "a" means one or more than one (i.e., at least one) grammatical object of the article. For example, "element" means one element or more than one element.

[0030] Unless otherwise indicated, all percentages (%) are "percent by weight".

[0031] The term "bio-based" means "composed of or derived in whole or in part from bioproducts produced from biomass (including plants, animals, and marine or forestry materials)". The use of bio-based (e.g., plant or animal) precursors or starting materials also results in the production of corresponding bio-based monomers / polymers / copolymers of plant or animal origin.

[0032] The term "bio-based content" means the fraction of a product derived from renewable biomass determined by testing a representative sample using the EN 16785-1 standard, expressed as a percentage of the total mass of the product.

[0033] The term "bio-based C2-C10 diol" means any C2-C10 diol that is bio-based.

[0034] The term "bio-based C7-C12 dicarboxylic acid" means any C7-C12 dicarboxylic acid that is bio-based.

[0035] The term "branched diol" means a diol capped by two hydroxyl groups and having at least one substituted alkyl, alkenyl, or alkynyl side group in its main chain.

[0036] The term "linear diol" means any diol capped directly by two hydroxyl groups and having no side groups in its main chain.

[0037] The term "alkyl" means a saturated straight-chain, branched-chain, or cyclic hydrocarbon group typically having from 1 to 36 carbon atoms, such as methyl, ethyl, propyl, 1-methylethyl (isopropyl), butyl, 1-methylpropyl (sec-butyl), 2-methylpropyl (isobutyl), 1,1-dimethylethyl (tert-butyl), pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, cyclopentyl, hexyl, 1-methylpentyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, 1-methylnonyl, 2-propylheptyl, n-dodecyl, 1-methyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, etc.

[0038] The term "alkylene" refers to a divalent straight-chain or branched hydrocarbon group typically having from 1 to 36 carbon atoms, for example, ethane-1,2-diyl, propane-1,3-diyl, propane-1,2-diyl, 2-methylpropane-1,2-diyl, butane-1,4-diyl, butane-1,3-diyl ( = 1-methylpropane-1,3-diyl), butane-1,2-diyl and butane-2,3-diyl.

[0039] The term "carboxyl" or "carboxyl group" refers to the functional group (-C(O)OH) in an organic carboxylic acid, such as acetic acid.

[0040] The term "hydroxyl value" refers to the mass (in milligrams) of potassium hydroxide (KOH) required to neutralize the acetic acid absorbed upon acetylation of one gram of a polyol or polyol blend. The hydroxyl value is determined according to German Standard Chemical Society (Deutsches Institut für Normung, DIN) 53240 since 2012 and is expressed as mgKOH / g.

[0041] The term "acid value" refers to the mass (in milligrams) of potassium hydroxide (KOH) required to neutralize the acidic groups in one gram of a polyol or polyol blend. The acid value is determined by German Standard Chemical Society (DIN) EN 12634 since 1999 (DIN standard of the Deutsches Institut fur Normung e.V.) and is expressed as mgKOH / g.

[0042] The "functionality" of a polyol refers to the number of hydroxyl groups per polyol molecule. The functionality of a blend of several polyols refers to the molar average of the functionality of all component polyols.

[0043] The term "isocyanate index" or "NCO index" of a polyurethane system refers to the ratio of the number of NCO groups present in the polyurethane system to the number of isocyanate-reactive hydrogen atoms, given as a percentage:

[0044]

[0045] [NCO] is the number of NCO groups.

[0046] [Isocyanate-reactive hydrogen] is the number of isocyanate-reactive hydrogen atoms.

[0047] In other words, the isocyanate index expresses the percentage of the isocyanate actually used in the formulation relative to the amount of isocyanate theoretically required to react with the amount of isocyanate-reactive hydrogen used in the formulation.

[0048] Unless otherwise specified, temperature refers to room temperature and pressure refers to ambient pressure.

[0049] Unless otherwise specified, the solvent refers to all organic and inorganic solvents known to those skilled in the art and does not include any type of monomer molecule.

[0050] Polyester polyol

[0051] The polyester polyol in the present disclosure comprises the condensation product of the following substances:

[0052] Biobased C7-C12 dicarboxylic acids;

[0053] Biobased C2-C10 diols; and

[0054] A branched diol having the following formula:

[0055]

[0056] Wherein R1 and R2 are independently straight-chain alkylene bonds having 1 to 3 carbon atoms, and R3 and R4 are independently alkyl groups having 1 to 3 carbon atoms, and wherein the weight ratio of the biobased C2-C10 diol to the branched diol is (25-53) to (47-75).

[0057] The condensation product is obtained by esterifying the biobased C2-C10 diol and the branched diol with the biobased C7-C12 dicarboxylic acid. The carboxyl groups present in the biobased C7-C12 dicarboxylic acid react with the hydroxyl groups present in the biobased C2-C10 diol and the branched diol at an elevated temperature to form ester bonds and water as a byproduct. The condensation can be carried out at an elevated temperature in a protective atmosphere, such as a nitrogen or any other inert gas atmosphere, optionally in the presence of a catalyst.

[0058] Preferably, the biobased C7-C12 dicarboxylic acid is suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, cyclohexanedicarboxylic acid, terephthalic acid, or any mixture thereof.

[0059] An exemplary biobased C7-C12 dicarboxylic acid is sebacic acid, which can be produced from castor oil by the cleavage of ricinoleic acid. Another example, cyclohexanedicarboxylic acid can be produced by the catalytic hydrogenation of biobased terephthalic acid, which can be obtained from Virent, Inc., Gevo, Inc., Anellotach, Inc., or Micromidas, Inc.

[0060] The sources and routes for preparing or obtaining such biobased C7-C12 dicarboxylic acids are known. The sources can be both naturally occurring organisms and genetically modified organisms, including plants, animals, or microorganisms.

[0061] Preferably, the biobased C2-C10 diol includes at least one linear diol, preferably at least one linear diol selected from the group consisting of 1,3-propanediol, trans-2-butene-1,4-diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,10-decanediol.

[0062] A common method for preparing such linear diols is the hydrogenation of the corresponding biobased linear C2-C10 dicarboxylic acids and / or their alkyl esters under elevated pressure in the presence of a catalyst such as Raney nickel. Another method is to reduce them with a reducing agent such as borohydride, lithium aluminum hydride, or diisobutylaluminum hydride. An especially exemplary biobased C2-C10 diol is 1,3-propanediol, which can be obtained by biosynthesis starting from glucose or glycerol by certain microorganisms. Another example of a biobased C2-C10 diol is 1,4-butanediol, which can be obtained by biosynthesis starting from 4-hydroxybutyrate by a genetically modified organism. Yet another example of a biobased C2-C10 diol is 1,10-decanediol, which can be obtained by the hydrogenation of sebacic acid, which can be produced by treating castor oil with an alkali metal hydroxide under heating.

[0063] Preferably, the biobased C2-C10 diol includes at least one cyclic diol, preferably at least one of isosorbide and tetrahydrofuran-2,5-dimethanol. In one embodiment, the biobased C2-C10 diol includes isosorbide. In one embodiment, the biobased C2-C10 diol includes tetrahydrofuran-2,5-dimethanol. In one embodiment, the biobased C2-C10 diol includes isosorbide and tetrahydrofuran-2,5-dimethanol.

[0064] The branched diol according to the present disclosure is represented by the following formula:

[0065]

[0066] wherein R1 and R2 are independently a linear alkylene bond having 1 to 3 carbon atoms, and R3 and R4 are independently an alkyl group having 1 to 3 carbon atoms.

[0067] Preferably, the branched diol is neopentyl glycol, methylpropanediol, 2-ethyl-1,3-propanediol, 2,2,4-trimethylpentane-1,3-diol, or any mixture thereof. In one embodiment, the branched diol comprises neopentyl glycol. In one embodiment, the branched diol comprises methylpropanediol. In one embodiment, the branched diol comprises 2-ethyl-1,3-propanediol. In one embodiment, the branched diol comprises 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises neopentyl glycol and methylpropanediol. In one embodiment, the branched diol comprises neopentyl glycol and 2-ethyl-1,3-propanediol. In one embodiment, the branched diol comprises neopentyl glycol and 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises methylpropanediol and 2-ethyl-1,3-propanediol. In one embodiment, the branched diol comprises methylpropanediol and 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises 2-ethyl-1,3-propanediol and 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises neopentyl glycol, methylpropanediol and 2-ethyl-1,3-propanediol. In one embodiment, the branched diol comprises neopentyl glycol, methylpropanediol and 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises neopentyl glycol, 2-ethyl-1,3-propanediol and 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises methylpropanediol, 2-ethyl-1,3-propanediol and 2,2,4-trimethylpentane-1,3-diol. In one embodiment, the branched diol comprises neopentyl glycol, methylpropanediol, 2-ethyl-1,3-propanediol and 2,2,4-trimethylpentane-1,3-diol.

[0068] In some embodiments, the branched diol may also be derived from biomass, i.e., the branched diol is bio-based. For example, there is already commercially available bio-based neopentyl glycol.

[0069] Preferably, the polyester polyol has a number average molecular weight of 1,000 g / mol to 3,000 g / mol.

[0070] Preferably, the molar ratio of the carboxyl groups in the bio-based C7-C12 dicarboxylic acid to the hydroxyl groups in both the bio-based C2-C10 diol and the branched diol is 1:(1.02 - 1.20). The excess hydroxyl groups relative to the carboxyl groups result in the hydroxyl group capping of the polyester polyol of the present disclosure.

[0071] Preferably, the polyester polyol has a viscosity of 8,000 mPas to 13,000 mPas at 25 °C as measured according to DIN EN 3219.

[0072] As a condensation product of several kinds of biobased raw materials, the polyester polyol according to the present disclosure can have a high biobased content. Preferably, the polyester polyol has a biobased content of higher than 60% by weight, more preferably higher than 65% by weight, further preferably higher than 70% by weight, further more preferably higher than 75% by weight, and even more preferably 80% by weight according to the EN 16785-1 standard.

[0073] The present disclosure also provides a method for preparing a polyester polyol, the method comprising:

[0074] a. Mixing a biobased C7-C12 dicarboxylic acid, a biobased C2-C10 diol, and a branched diol in a reaction vessel, and obtaining a mixture;

[0075] b. Heating the mixture at a first temperature in the range of 180°C to 250°C for a first duration;

[0076] c. Continuing to heat under a subatmospheric pressure inside the reaction vessel to obtain a crude product;

[0077] d. Heating the crude product at a second temperature in the range of 100°C to 150°C for a second duration in the range of 1 hour to 4 hours, and removing one or more volatile impurities; and

[0078] e. Separating the polyester polyol from the crude product after step (d), wherein the branched diol has the following formula:

[0079]

[0080] R1 and R2 are independently a straight-chain alkylene bond having 1 to 3 carbon atoms, and R3 and R4 are independently an alkyl group having 1 to 3 carbon atoms.

[0081] The method employs the condensation of the above reactants to form the polyester polyol according to the present disclosure.

[0082] The inside of the reaction vessel can have a protective atmosphere. Preferably, the protective atmosphere is an atmosphere with a reduced oxygen content, a nitrogen atmosphere, or any other inert atmosphere. Using a protective atmosphere inside the reaction vessel can reduce side reactions caused by oxygen in the surrounding environment and improve the color of the polyester polyol obtained from the method.

[0083] Preferably, in step (b), the mixture is heated at a first temperature in the range of 200°C to 240°C. The heating can be accompanied by purging with nitrogen or other inert gases to facilitate the removal of water as a condensation reaction product.

[0084] Preferably, the subatmospheric pressure is in the range of 5 mbar to 0.8 bar, more preferably in the range of 10 mbar to 0.5 bar.

[0085] Preferably, the first duration is from 1 hour to 6 hours, more preferably from 2 hours to 5 hours.

[0086] When the crude product is heated at a temperature below the first temperature, the esterification reaction can be substantially stopped. Heating can remove one or more impurities (which are usually sources of volatile organic compounds (VOCs)) without causing side reactions. The polyester polyol separated in step (e) can have a low content of VOCs, which is desirable in various applications such as smart wearable products, personal devices, household appliances, automotive components or furniture.

[0087] Polyurethane system

[0088] To prepare a polyurethane foam or a dense polyurethane, a polyurethane system is provided. In various embodiments, the polyurethane system comprises a polyol component and an isocyanate component, wherein the polyol component comprises:

[0089] a polyester polyol according to the present disclosure; and

[0090] one or more catalysts.

[0091] Preferably, the polyurethane system further comprises a blowing agent.

[0092] Preferably, the weight ratio of the polyol component to the isocyanate component is such that the isocyanate index is from 80% to 500%, preferably from 90% to 450%, more preferably from 100% to 150%.

[0093] The preparation of the polyurethane essentially involves the reaction of the polyol and the catalyst with the isocyanate optionally in the presence of a chain extender, a blowing agent and / or other additives.

[0094] Polyol component

[0095] The polyol component comprises a polyester polyol according to the present disclosure; and one or more catalysts.

[0096] Preferably, based on the total weight of the polyol component, the polyester polyol has a weight percentage of from 50 wt% to 100 wt%, preferably from 60 wt% to 95 wt%, more preferably from 70 wt% to 80 wt%.

[0097] Optionally, the polyol component may further comprise a chain extender or a crosslinking agent; a blowing agent; and one or more additives and / or adjuvants.

[0098] Other polyester polyols, polyether polyols and polycarbonate polyols

[0099] In additional embodiments, the polyester polyols provided in the present disclosure can be used in combination with other polyols. The other polyols include other polyester polyols, polyether polyols, or polycarbonate polyols.

[0100] Polyester polyols, polycarbonate polyols, and polyether polyols are collectively referred to as polyols. Polyols refer to polyhydroxy compounds. Preferably, polyhydroxy compounds having a functionality of 2 to 8, more preferably 2 to 3, and a hydroxyl value of 150 mg KOH / g to 850 mg KOH / g, more preferably 200 mg KOH / g to 600 mg KOH / g, are examples of higher molecular weight compounds having at least two isocyanate-reactive hydrogen atoms. In addition, mixtures of at least two of the above polyhydroxy compounds can be used as long as these polyhydroxy compounds have an average hydroxyl value within the above range. Polyols other than the bio-based polyester polyols according to the present disclosure can be used alone or in the form of a mixture.

[0101] Polyester polyols can be produced, for example, from organic dicarboxylic acids having 2 to 12 carbons, preferably aliphatic dicarboxylic acids having 4 to 6 carbons, and polyhydric alcohols having 2 to 12 carbons, preferably diols, having 2 to 6 carbons. Examples of dicarboxylic acids include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, and terephthalic acid. The dicarboxylic acids can be used alone or in a mixture. Instead of the free dicarboxylic acids, the corresponding dicarboxylic acid derivatives, such as mono-esters or di-esters of dicarboxylic acids with alcohols having 1 to 4 carbons, or dicarboxylic acid anhydrides, can also be used. A dicarboxylic acid mixture of succinic acid, glutaric acid, and adipic acid in a weight ratio of 20 - 35:35 - 50:20 - 32 parts is preferred, especially adipic acid. Examples of dihydric alcohols and polyhydric alcohols, especially diols, include ethylene glycol, diethylene glycol, 1,2- and 1,3-propanediol, 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.

[0102] Polyester polyols can also be produced from initiators in the form of small molecule diols, triols, or higher polyhydroxy alcohols, such as ethylene glycol, glycerol, or pentaerythritol, and polylactones in the presence of a catalyst. Ring-opening reactions produce polyester polyols. Such polyester polyols include, without limitation, polylactide polyols and polycaprolactone polyols.

[0103] The polycondensation of an organic polycarboxylic acid (e.g., an aromatic or preferably aliphatic polycarboxylic acid and / or its derivatives) with a polyhydric alcohol can occur 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.), in a melt at a temperature of 150 °C to 250 °C, preferably 180 °C to 220 °C, optionally under reduced pressure, until the desired degree of polymerization (which is preferably less than 10, especially less than 5). In a preferred embodiment, the esterification mixture is subjected to polycondensation at the above temperature at atmospheric pressure and then at a pressure of less than 500 mbar, preferably 50 mbar to 150 mbar, until an acid value of 80 mg / g to 30 mg / g, preferably 40 mg / g to 30 mg / g. Examples of suitable esterification catalysts include iron catalysts, cadmium catalysts, cobalt catalysts, lead catalysts, zinc catalysts, antimony catalysts, magnesium catalysts, titanium catalysts, 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 a diluent and / or an entrainer (such as benzene, toluene, xylene, or chlorobenzene) for the azeotropic distillation of the water formed during the condensation.

[0104] For the production of polyester polyols, the organic polycarboxylic acid and / or its derivatives are preferably polycondensed with the polyhydric alcohol in a molar ratio of 1:1 - 1.8, preferably 1:1.05 - 1.2.

[0105] Polyether polyols obtainable by known methods can also be used as polyhydroxy compounds. 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 alkoxide (such as sodium methoxide, sodium ethoxide, potassium ethoxide, or potassium isopropoxide) as a catalyst and adding at least one initiator molecule containing 2 to 3 isocyanate-reactive hydrogens, or by cationic polymerization using a Lewis acid (such as antimony pentachloride, boron trifluoride etherate) or bleaching earth as a catalyst from one or more alkylene oxides having 2 to 4 carbons in the alkylene radical.

[0106] Cyclic ethers and epoxides include, for example, tetrahydrofuran, 1,3 - epoxypropane, 1,2 - and 2,3 - epoxybutane, styrene oxide, and preferably ethylene oxide and 1,2 - epoxypropane. Alkylene cyclic ethers and oxides can be used individually, alternately, one after another, or as a mixture. Examples of initiator molecules include: water, polyhydric alcohols, organic dicarboxylic acids (such as succinic acid, adipic acid, phthalic acid, and terephthalic acid), aliphatic and aromatic (optionally N - monosubstituted, N,N - dialkyl - substituted, and N,N'-dialkyl - substituted) diamines having 1 to 4 carbons in the alkyl radical, such as optionally monosubstituted and dialkyl - substituted ethylenediamine, diethylenetriamine, triethylenetetramine, 1,3 - propanediamine, 1,3 - and 1,4 - butanediamine, 1,2 -, 1,3 -, 1,4 -, 1,5 -, and 1,6 - hexanediamine, phenylenediamine, 2,3 -, 2,4 -, and 2,6 - toluenediamine, and 4,4' -, 2,4' -, and 2,2' - diaminodiphenylmethane.

[0107] Polyhydric alcohols, especially dihydric, trihydric, and / or tetrahydric alcohols are preferred, such as ethylene glycol, 1,2 - propanediol and 1,3 - propanediol, diethylene glycol, dipropylene glycol, 1,4 - butanediol, 1,6 - hexanediol, glycerol, trimethylolpropane, erythritol, pentaerythritol, sorbitol, and sucrose.

[0108] Initiator molecules also include alkanolamines, such as ethanolamine, diethanolamine, N - methyl and N - ethyl ethanolamine, N - methyl and N - ethyl diethanolamine, and triethanolamine plus ammonia.

[0109] Polycarbonate polyols are polycarbonates containing hydroxyl groups, including those obtained by the reaction of diols (e.g., 1,3 - propanediol, 1,4 - butanediol, and / or 1,6 - hexanediol, diethylene glycol, triethylene glycol, or tetraethylene glycol) with diaryl carbonates (e.g., diphenyl carbonate) or phosgene.

[0110] Catalyst

[0111] The catalysts used in the present disclosure may include one or more catalysts selected from metal - based catalysts and amine - based catalysts. The catalysts can greatly accelerate the reaction of the component containing hydroxyl groups and optionally with polyisocyanates.

[0112] The metal-based catalyst may include organotin compounds such as tin(II) salts of organic carboxylic acids (e.g., tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate, and tin(II) laurate) and dialkyltin(IV) salts of organic carboxylic acids (e.g., dibutyltin diacetate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate). The metal-based catalyst may include potassium compounds 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.

[0113] Examples of amine-based catalysts may 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'-tetramethylbutanediamine or hexamethylenediamine, pentamethyldiethylenetriamine, tetramethyldiaminoethylether, bis(dimethylaminopropyl)urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo[3.3.0]octane and preferably 1,4-diazabicyclo[2.2.2]octane, and alkanolamine compounds such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine and dimethylethanolamine.

[0114] Suitable catalysts include tris(dialkylamino-s-hexahydrotriazine, 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-dependent groups. Those skilled in the art can select specific catalysts or combinations of catalysts.

[0115] Chain extender and crosslinking agent

[0116] Polyurethanes can be prepared with or without chain extenders and / or crosslinking agents. Suitable chain extenders and / or crosslinking agents preferably include alkanolamines, more preferably diols and / or triols. A group of examples includes alkanolamines such as ethanolamine and / or isopropanolamine; dialkanolamines such as diethanolamine, N-methyl-, N-ethyldiethanolamine, diisopropanolamine; trialkanolamines such as triethanolamine, triisopropanolamine; and addition products of ethylene oxide or 1,2-propylene oxide with alkylenediamines having 2 to 6 carbon atoms in the alkylene radical such as N,N'-tetrakis(2-hydroxyethyl)-ethylenediamine and N,N'-tetrakis(2-hydroxypropyl)-ethylenediamine. Another group of examples includes aliphatic, cycloaliphatic and / or araliphatic diols having 2 to 14, more preferably 4 to 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,10-decanediol, o-, m-, p-dihydroxycyclohexane, diethylene glycol, dipropylene glycol, 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 hydroxy group-containing polyalkylene oxides based on ethylene oxide and / or 1,2-propylene oxide and aromatic diamines such as toluenediamine and / or diaminodiphenylmethane and the above alkanolamines, diols and / or triols as initiator molecules.

[0117] Foaming agent

[0118] The blowing agents that can be used are physical blowing agents and chemical blowing agents.

[0119] Compounds known as physical blowing agents can also preferably be used in combination with water or preferably in place of water. These are compounds that are inert with respect to the starting components, are mainly liquid at room temperature, and evaporate under the conditions of the polyurethane reaction. The boiling points of these compounds are preferably below 500 °C. Among the physical blowing agents there are also compounds that are gases at room temperature and are introduced or dissolved into the starting components under pressure, examples being carbon dioxide, low-boiling alkanes and fluorinated alkanes.

[0120] The physical blowing agents are mainly selected 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, especially tetramethylsilane. Examples that 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 that can degrade in the troposphere and thus do not damage the ozone layer, such as 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 may be used alone or in any desired combination with each other.

[0121] The 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.

[0122] Based on the total weight of the polyol component, the amount of the blowing agent is 1 wt% to 55 wt%, preferably 1 wt% to 40 wt%, particularly preferably 2 wt% to 30 wt%, and especially 5 wt% to 25 wt%.

[0123] In some embodiments, based on the weight of the polyol component, the amount of water is preferably in the range of 0.1 wt% to 5.0 wt%.

[0124] Other additives

[0125] Optionally, other additives may be incorporated into the polyol component. Examples include flame retardants, surfactants, foam stabilizers, defoamers, cell regulators, fillers, dyes, pigments, hydrolysis inhibitors, fungicides, and bactericides.

[0126] Preferably, the flame retardant includes at least one phosphorus-containing flame retardant, and the at least one phosphorus-containing flame retardant is a derivative of phosphoric acid, polyphosphoric acid, phosphonic acid, and / or hypophosphorous acid. The flame retardant for the purposes of the present disclosure is preferably a liquid organophosphorus compound, such as a halogen-free organophosphate (such as triethyl phosphate (TEP)), a halogenated phosphate (such as tris(1-chloro-2-propyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP)), and an organophosphonate (such as dimethyl methylphosphonate (DMMP), dimethyl propane phosphonate (DMPP)); or a solid, such as ammonium polyphosphate (APP) and red phosphorus. In addition, in addition to the 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.

[0127] Examples of surfactants are compounds that support the homogenization of the starting materials and can also regulate the cell structure of the plastic. Specific examples are salts of sulfonic acids, such as the alkali metal salts or ammonium salts of fatty acids (such as oleic acid or stearic acid), dodecylbenzene or dinaphthylmethanedisulfonic acid and ricinoleic acid; foam stabilizers (such as silicone-alkylene oxide copolymers and other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oil, castor oil esters, ricinoleic acid esters, Turkey red oil and arachis oil) and cell regulators (such as paraffin, fatty alcohols and dimethylpolysiloxane). Surfactants are usually used in an amount of from 0.01 parts by weight to 5 parts by weight based on 100 parts by weight of the polyol component. In addition, low molecular weight polyacrylates with polyoxyalkylene and fluoroalkane side groups are also suitable for improving the emulsification effect, cell structure and / or for stabilizing the foam. These surfactants are usually used in an amount of from 0.01 wt% to 5 wt% based on the weight of the polyol component.

[0128] For example, the fillers are conventional organic and inorganic fillers and reinforcing agents. Specific examples are inorganic fillers such as silicate minerals, such as phyllosilicates, such as antigorite, serpentine, amphibole, tremolite, wollastonite and talc; metal oxides, such as kaolin, alumina, titanium oxide and iron oxide; metal salts, such as chalk, barite, and inorganic pigments, such as especially cadmium sulfide, zinc sulfide and glass; kaolin (china clay), aluminum silicate, and coprecipitates of barium sulfate and aluminum silicate, and natural and synthetic fibrous minerals, such as wollastonite, metals, and glass fibers of various lengths. Examples of suitable organic fillers are: carbon black, melamine, rosin, cyclopentadienyl resin, cellulose fibers, polyamide fibers, polyacrylonitrile fibers, polyurethane fibers and polyester fibers based on aromatic and / or aliphatic dicarboxylic esters, and especially carbon fibers. The inorganic fillers 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 from 0.5 wt% to 40 wt% based on the weight of the components (polyol and isocyanate).

[0129] Isocyanate component

[0130] The isocyanate component in the present disclosure comprises one or more selected from the group consisting of aliphatic isocyanates, cycloaliphatic isocyanates, araliphatic isocyanates, and aromatic isocyanates. For example, the isocyanate component may comprise an alkylene diisocyanate having 4 to 12 carbons in the alkylene radical, 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; cycloaliphatic diisocyanates, such as 1,3- and 1,4-cyclohexane diisocyanates and any mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluene diisocyanates and the corresponding isomer mixtures, 4,4'-2,2'- and 2,4'-dicyclohexylmethane diisocyanates and the corresponding isomer mixtures, and preferably aromatic diisocyanates and polyisocyanates, such as 2,4- and 2,6-toluene diisocyanate (TDI) and the corresponding isomer mixtures 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI) and mixtures of polyphenyl polymethylene polyisocyanates (polymeric MDI), and mixtures of polymeric MDI and toluene diisocyanate. The organic diisocyanates and polyisocyanates may be used alone or in the form of mixtures. Preferably, the isocyanate component comprises not less than 90% by weight of monomeric and / or polymeric diphenylmethane diisocyanate.

[0131] Foams and elastomers

[0132] According to the present disclosure, polyurethane foams or elastomers can be produced from a polyol component and an isocyanate component.

[0133] The polyurethane foam can be prepared by means of conventional mixing equipment.

[0134] It should be observed that, as used herein, the isocyanate index is considered from the perspective of the actual foaming process involving the isocyanate component and the isocyanate-reactive components. Any isocyanate groups consumed in the preparatory steps for producing modified polyisocyanates (including such isocyanate derivatives known in the art as prepolymers) or any isocyanate-reactive hydrogens consumed in the preparatory steps (e.g., reacting with isocyanates to produce modified polyols or polyamines) are not considered in the calculation of the isocyanate index. Only the free isocyanate groups and free isocyanate-reactive hydrogens (including those of water) present at the actual foaming process are considered.

[0135] The polyurethane foam can also be applied to furniture, packaging materials, synthetic leather, bumpers, mattresses, liners, car seats, footwear, cleaning products, thermal insulation boards or sheets in clean rooms or cold storages, sandwich panels in building roofs, waterproof boards or sheets.

[0136] In some cases, the polyurethane foam according to the present disclosure can be included in a composite material. For example, the composite material can be a sandwich panel. The sandwich panel can include the polyurethane foam as its core layer. The sandwich panel can contain a metal layer as the outer layer.

[0137] The polyurethane elastomer can be applied to coatings, protective materials, cushioning materials, seals, bearings, wheels or belts.

[0138] Examples

[0139] The materials used in the examples are as follows.

[0140] Sebacic acid, from BASF, CAS No. 111-20-6.

[0141] 1,3-Propanediol, "PDO", a straight-chain diol from BASF, CAS No. 504-63-2.

[0142] Neopentyl glycol, "NPG", a branched-chain diol from BASF, CAS No. 126-30-7.

[0143] Ethylene glycol, used as a chain extender in the polyol component, from BASF, CAS No. 107-21-1.

[0144] 4,4'-Diphenylmethane diisocyanate (MDI), from BASF, CAS No. 101-68-8.

[0145] PESOL 2 is a polyester polyol with a functionality of 2 and a hydroxyl value of 56 mg KOH / g.

[0146] EG, 33 wt% triethylenediamine (CAS No. 280-57-9) dissolved in ethylene glycol, from Evonik, used as a catalyst.

[0147] Synthesis of polyester polyol

[0148] The chemical route for synthesizing the polyester polyol according to the present disclosure is the esterification of a biobased C7-C12 dicarboxylic acid with a mixture of a biobased C2-C10 diol and a branched-chain diol. This synthesis can follow a one-pot method.

[0149] In a typical one-pot process, bio-based sebacic acid is mixed with bio-based 1,3-propanediol and neopentyl glycol. A pasty mixture is obtained. The mixture is placed inside a flask. No catalyst is added. However, a small amount of catalyst, such as tetrabutyl titanate, may be added to accelerate the esterification or lower the reaction temperature. The flask is equipped with a column and a condenser to collect the condensation products. During the synthesis, the apparatus is continuously purged with nitrogen or other inert gases to limit oxidation and facilitate the transport of water vapor out of the reaction system. While stirring, the mixture is heated to 230 °C using a heating device. The heating continues for ten (10) hours. The reaction temperature is gradually increased to maintain the distillation of the by-products formed. The water obtained from the esterification is removed in situ.

[0150] When the collected distilled water reaches approximately 80% of the theoretical amount of water as the esterification product, the flask is depressurized to 20 mbar. Heating is continued for ten (10) hours. After the acid value of the mixture is below 2.0 mg / g, the mixture is cooled to 120 °C. The temperature of the mixture is maintained at 120 °C for an additional four (4) hours. The pressure is kept at 20 mbar.

[0151] After the synthesis, the hydroxyl value and the viscosity value are measured. The hydroxyl value is determined by titration. The viscosity value is tested at 25 °C according to DIN EN 3219. The final acid value of the product is less than 1.0 mg / g.

[0152] In the product thus prepared, the content of the cyclic oligomers formed by the reaction of sebacic acid with 1,3-propanediol is less than 50 ppm, which is confirmed by liquid chromatography mass spectrometry analysis. The cyclic oligomers can be in the form of lactones.

[0153] In the following table, "PO" refers to the polyester polyol according to the present disclosure, while "CPO" refers to the comparative polyester polyol.

[0154] Table 1 Raw materials for preparing polyester polyol

[0155]

[0156] In Table 2, "PF" refers to the sample made from the polyester polyol according to the present disclosure, while "CPF" refers to the sample made from the comparative polyester polyol.

[0157] Table 2 Composition of polyurethane system

[0158]

[0159] Polyurethane systems are made into elastomer samples. The samples all have 600 kg / m 3Molding density. The tensile strength of the test specimens was tested according to DIN 53504. To evaluate the anti-aging properties, the specimens were placed in an environmental test chamber where the temperature and relative humidity were set at 70 °C and 95%, respectively.

[0160] Table 3 Properties of samples prepared from polyurethane system

[0161]

[0162] As shown in the table above, the specimens prepared from the polyurethane system exhibited a durable tensile strength even after the aging test at high temperature and high humidity levels.

Claims

1. A polyester polyol, the polyester polyol comprising the condensation product of: A bio-based C7-C12 dicarboxylic acid; A bio-based C2-C10 diol; and A branched diol having the following formula: wherein R1 and R2 are independently straight-chain alkylene bonds having 1 to 3 carbon atoms, and R3 and R4 are independently alkyl groups having 1 to 3 carbon atoms, and wherein the weight ratio of the bio-based C2-C10 diol to the branched diol is (25 - 53) to (47 - 75).

2. The polyester polyol according to claim 1, wherein the bio-based C7-C12 dicarboxylic acid is suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, cyclohexanedicarboxylic acid, terephthalic acid, or any mixture thereof.

3. The polyester polyol according to claim 1, wherein the bio-based C2-C10 diol comprises at least one straight-chain diol, preferably at least one straight-chain diol selected from the group consisting of: 1,3-propanediol, trans-2-butene-1,4-diol, 1,4-butanediol, 1,5-pentanediol, and 1,10-decanediol.

4. The polyester polyol according to claim 3, wherein the branched diol is neopentyl glycol, methylpropanediol, 2-ethyl-1,3-propanediol, 2,2,4-trimethylpentane-1,3-diol, or any mixture thereof.

5. The polyester polyol according to claim 1, wherein the polyester polyol has a number average molecular weight of 1,000 g / mol to 3,000 g / mol.

6. The polyester polyol according to any one of claims 1 to 5, wherein the molar ratio of the carboxyl groups in the bio-based C7-C12 dicarboxylic acid to the hydroxyl groups in both the bio-based C2-C10 diol and the branched diol is 1:(1.02 - 1.20).

7. The polyester polyol according to any one of claims 1 to 5, wherein the polyester polyol has a viscosity of 8,000 mPas to 13,000 mPas at 25 °C as measured according to DIN EN 3219.

8. The polyester polyol according to claim 1, wherein the polyester polyol has a bio-based content of higher than 60 wt%, preferably higher than 65 wt%, more preferably higher than 70 wt%, further preferably higher than 75 wt%, further more preferably 80 wt% according to the EN 16785-1 standard.

9. A polyurethane system, the polyurethane system comprising: A polyol component; and An isocyanate component, wherein the polyol component comprises The polyester polyol according to any one of claims 1 to 7; and One or more catalysts.

10. The polyurethane system according to claim 9, wherein based on the total weight of the polyol component, the polyester polyol has a weight percentage of 50 wt% to 100 wt%, preferably 60 wt% to 95 wt%, more preferably 70 wt% to 80 wt%.

11. The polyurethane system according to claim 9, the polyurethane system further comprising a blowing agent.

12. The polyurethane system according to claim 9, wherein the weight ratio of the polyol component to the isocyanate component is such that the isocyanate index of the polyurethane system is from 80% to 500%, preferably from 90% to 450%, more preferably from 100% to 150%.

13. A method for preparing a polyester polyol, the method comprising: (a) In a reaction vessel, mixing a bio-based C7-C12 dicarboxylic acid, a bio-based C2-C10 diol, and a branched diol, and obtaining a mixture; (b) Heating the mixture at a first temperature in the range of 180 °C to 250 °C for a first duration; (c) Heating the crude product at a second temperature in the range of 100 °C to 150 °C for a second duration in the range of 1 hour to 4 hours; and (d) Separating the polyester polyol from the crude product after step (c), wherein the branched diol has the following formula: R1 and R2 are independently a straight-chain alkylene bond having 1 to 3 carbon atoms, and R3 and R4 are independently an alkyl group having 1 to 3 carbon atoms.

14. The method according to claim 13, wherein step (b) comprises heating the mixture at a subatmospheric pressure in the range of 5 mbar to 0.8 bar, preferably 10 mbar to 0.5 bar.

15. The method according to claim 13, wherein the first duration is from 1 hour to 6 hours, preferably from 2 hours to 5 hours.

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