Sustainable polyols for polyisocyanurate rigid foam useful in insulation boards

Abstract

Sustainable aromatic polyester polyols from biobased and / or recycled aromatic compounds are disclosed. The aromatic polyester polyols are useful in the production of polyisocyanurate hard foam for example for insulation boards.

Description

[0001] SUSTAINABLE POLYOLS FOR POLYISOCYAN URATE RIGID FOAM USEFUL IN INSULATION BOARDS

[0002] TECHNICAL FIELD

[0003] The present invention relates to biobased aromatic building blocks useful in the production of polyisocyan urate rigid (PIR.) foam. PIR. foam has been used in insulation boards because of its high thermal and flame resistance and low smoke generation during burning. One of the main raw materials for PIR. production are aromatic polyester polyols.

[0004] INTRODUCTION

[0005] Aromatic polyester polyols are vital components in the production of polyurethane and polyisocyan urate foams, which are widely used in various industrial applications due to their excellent mechanical and thermal properties. These materials are essential in the construction, automotive, and appliance industries, where they serve as insulators, structural elements, and components in flexible and rigid foam products.

[0006] Polyester polyols are typically synthesized through the polycondensation of polycarboxylic acids or their anhydrides with polyols. The resulting polyesters can be tailored to exhibit specific properties by altering the types and ratios of the reactants. Aromatic compounds, in particular, contribute to the rigidity, thermal stability, and flame retardance of the resulting polyesters, making them highly desirable for applications requiring enhanced performance characteristics.

[0007] In recent years, there has been a growing emphasis on developing sustainable and environmentally friendly materials. This has led to increased research and innovation in the use of biobased and recycled materials in polymer synthesis. The integration of biobased feedstocks and recycled components not only reduces dependence on fossil resources but also contributes to the reduction of carbon footprints and environmental impact.

[0008] The development of novel aromatic polyester polyols incorporating these sustainable materials is a significant advancement in the field. It aligns with global trends towards greener and more sustainable chemical processes. These innovations hold the potential to meet the high-performance demands of modern industrial applications while also addressing environmental and sustainability concerns.

[0009] In this regard, EP 4 186 936 Al provides polyester polyols used in one component foam or foam adhesive, wherein the polyester polyol has a hydroxyl value in the range of 80-240 mg KOH / g, functionality from 2 to 3 and viscosity below 5000 mPa.s at 25°C and biocarbon content measured according to ASTM D6866-18 is no less than 89%, wherein the polyester polyol is obtainable by reacting at least two polyhydroxyl alcohols, wherein at least one is a bio-based polyhydroxyl alcohol, each comprising at least two hydroxyl groups, at least one dicarboxylic acid, preferably a bio-based or a sustainably produced dicarboxylic acid, at least one modifier, in the presence of a catalyst; and a bio-based one component polyurethane foam or adhesive foam composition comprising a polyester polyol component, an isocyanate component, plasticiser, surfactant, flame retardant, catalyst, propellant gas and at least one polyether polyol, wherein the biocarbon content measured according to ASTM D6866-18 is at least 20% by weight. The invention also discloses a use of the biobased polyester polyol for manufacturing one component construction foam or foam adhesive.

[0010] WO 2024 / 120827 Al provides a polyester polyol including a condensation product of a biobased C7-C12 dicarboxylic acid, a biobased C2-C10 diol, and a branched diol having a linear alkylene linkage having 1 to 3 carbon atoms, wherein the weight ratio of the biobased C2-C10 diol to the branched diol is (25-53) to (47-75) as well as a polyurethane system comprising the polyester polyol and a process of preparing the polyester polyol.

[0011] As demand for biobased, bio-resourced and recycled products increases, there is a need for novel pathways to sustainable and durable products incorporating such resources with little or no negative impact on the synthetic pathways and processes and compatible with industry processes and standards.

[0012] SUMMARY

[0013] The current invention provides a solution to the aforementioned problems by proposing a novel class of sustainable aromatic polyester polyols obtained from reacting one or more aromatic compounds with one or more non-aromatic polyols, whereby said aromatic compound comprises 3-methyl phthalic anhydride (MPA). The inventors have discovered that MPA is a useful novel, partially biobased aromatic building block suitable for the production of PI R. foam. Novel combinations of MPA with FDCA and / or rPET in polyol formulations have also been identified. The chemical structures of biobased and rPET-based building blocks differ significantly from those of conventional fossil-fuel-based building blocks, presenting challenges in the development of biobased, rPET-based, and hybrid polyols - i.e. polyols comprising a partial biobased and partial recycled content. Such polyols for PIR applications are not commercially available.

[0014] A further aspect of the present invention is a polyisocyanurate hard foam obtained by reacting the aromatic polyester polyols of the invention with methylene diphenyl diisocyanate (MDI) followed by a trimerization of terminal isocyanate groups to form isocyanuarate groups. A further aspect of the present invention is an insulation board comprising the polyisocyanurate hard foam of the invention.

[0015] DETAILED DESCRIPTION OF THE INVENTION

[0016] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0017] By means of further guidance, term definitions are included to better appreciate the teaching of the present invention. As used herein, the following terms have the following meanings:

[0018] "A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0019] "About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / - 20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed. "Comprise," "comprising," and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0020] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0021] All percentages are to be understood as percentage by weight, abbreviated as "wt.%" or as volume per cent, abbreviated as "vol.%", unless otherwise defined or unless a different meaning is obvious to the person skilled in the art from its use and in the context wherein it is used.

[0022] MPA 3-methyl phthalic anhydride

[0023] PA phthalic anhydride

[0024] FDCA 2,5-furandicarboxylic acid

[0025] DEG diethylene glycol

[0026] PIR. polyisocyanurate rigid foam

[0027] PET polyethylene terephthalate rPET recycled PET, preferably PET recycled by glycolysis

[0028] The term "biobased" refers to materials composed or derived, in whole or in part, from biological products originating from biomass, which includes plant, animal, marine, or forestry materials. Utilizing biobased precursors or starting materials results in the production of corresponding biobased monomers, polymers, or copolymers of vegetable or animal origin. The aromatic compounds of the present invention are preferably biobased, meaning they are sourced or derived from plants, animals, algae, fungi, or bacteria, with a particular preference for plant-based sources. In a preferred embodiment, biobased excludes the presence of fossil-fuel-based compounds. In a preferred embodiment, biobased materials used in the present invention exclude food resources.

[0029] The term "biobased content" denotes the proportion of a product derived from renewable biomass. This proportion is expressed as a percentage of the total mass of the product and is determined by testing representative samples in accordance with the EN 16785-1 standard.

[0030] The term "hydroxyl number" is defined as the mass of potassium hydroxide (KOH), in milligrams, necessary to neutralize the acetic acid absorbed during the acetylation of one gram of a polyol or a mixture of polyols. This measurement, reported in milligrams of KOH per gram (mg KOH / g), determined according to DIN standard 53240 from 2012.

[0031] The term "acid number" denotes the mass of potassium hydroxide (KOH), in milligrams, required to neutralize the acidic groups in one gram of a polyol or a blend of polyols. This value, also expressed in milligrams of KOH per gram (mg KOH / g), determined according to DIN standard EN 12634 from 1999.

[0032] The term "functionality" of a polyol refers to the number of hydroxyl groups present per polyol molecule. When discussing a blend of multiple polyols, functionality is understood as the molar average of the functionalities of all individual polyols within the mixture.

[0033] The term "recycled" means by chemical recycling of PET. Chemical recycling refers to the chemical depolymerization of PET via hydrogenolysis or solvolysis. Five different forms of solvolysis are defined depending on the depolymerization agent and leading to a different monomer output: glycolysis, alcoholysis, hydrolysis, aminolysis and ammonolysis. In a preferred embodiment, the PET is recycled by glycolysis, as shown in chemical reaction.

[0034] Glycolysis is the chemical PET recycling method with the highest commercial maturity. During glycolysis a trans-esterification catalyst breaks the ester bonds in the polymer and replaces them with end-hydroxyl groups. In general, glycolysis requires high temperatures, such as 110 °C to 270 °C and long reaction times, such as up to 15 hours. When using DEG in the glycolysis process bis-2-hydroxyethyl terephthalate (BHET) is obtained which in turn can serve as a raw material for the synthesis of polyester polyols by reacting it with a dicarboxylic acid. In addition to DEG, other glycols can be used during the glycolysis. For example, by using propylene glycol as depolymerization agent, BHET analogues were obtained and used for the synthesis of unsaturated polyester resins.

[0035] The present invention provides in a first aspect aromatic polyester polyols obtained from reacting one or more aromatic compounds with one or more non-aromatic polyols, whereby said aromatic compound comprises 3-methyl phthalic anhydride (MPA). It is hereby demonstrated that MPA is a useful novel biobased aromatic building block suitable for the production of PIR foam. Novel combinations of MPA with FDCA, PA and / or rPET in polyol formulations have also been identified. The chemical structures of biobased and rPET-based building blocks differ significantly from those of conventional fossil-fuel-based building blocks, presenting challenges in the development of biobased, rPET-based, and hybrid polyols - i.e. polyols comprising a partial biobased and partial recycled content. Such polyols for PIR. applications are not commercially available. The polyester polyols described herein may possess a substantial biobased content. Preferably, this content exceeds 50 wt.%, more preferably exceeds 60 wt.%, even more preferably exceeds 70 wt.%, further more preferably exceeds 75 wt.%, and most preferably exceeds 80 wt.%, as measured by the EN 16785-1 standard.

[0036] The 3-methyl phthalic anhydride (MPA) of the invention is preferably biobased, and preferably is plant-based. Small amounts of non-biobased MPA may be present, such as 10 wt.% or less, preferably 5 wt.% or less, even more preferably 1 wt.% or less as compared to the total amount of the MPA in the aromatic polyester polyols of the invention. 2,5-furandicarboxylic acid (FDCA) if used in the context of the present invention is preferably biobased, and preferably is plant-based. Small amounts of non-biobased FDCA may be present, such as 10 wt.% or less, preferably 5 wt.% or less, even more preferably 1 wt.% or less as compared to the total amount of the FDCA in the aromatic polyester polyols of the invention.

[0037] The aromatic polyester polyols of the present invention reduce the consumption of fossil-fuels as they are obtained from biobased or recycled building blocks. The aromatic polyester polyols of the present invention are thus a sustainable alternative to fossil-fuel based building blocks used in the production of PIR. foam for insulation board.

[0038] In one embodiment, the weight ratio (w / w) from MPA:FDCA is from 1 :9 to 1 :0, preferably from 3: 1 to 1:3, even more preferably from 2: 1 to 1 :2, even more preferably from 1.5: 1 to 1 : 1.5.

[0039] Exemplary weight ratios (w / w) from MPA: FDCA include:

[0040] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, whereby said 3-methyl phthalic anhydride is biobased. In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the biobased aromatic compounds are derived from plants, animals, algae, fungi, or bacteria, and preferably are plant-based.

[0041] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein said aromatic compound further comprises biobased 2,5-furandicarboxylic acid (FDCA), phthalic anhydride (PA) and / or chemically recycled polyethylene terephthalate (rPET).

[0042] In one embodiment, the aromatic compound is MPA, FDCA or a mixture thereof. In a preferred embodiment, the MPA, FDCA or a combination thereof are biobased. In another embodiment, the aromatic compound comprises MPA and further PA and / or rPET. In a one specific embodiment, the one or more aromatic compounds comprise 25 wt.% or less of fossil-fuel based aromatic compounds, preferably 15 wt.% or less of fossil-fuel based aromatic compounds, even more preferably 10 wt.% or less of fossil-fuel based aromatic compounds, even more preferably 5 wt.% or less of fossil- fuel based aromatic compounds, and even more preferably 1 wt.% or less of fossilfuel based aromatic compounds.

[0043] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein one or more aromatic compounds are obtained by glycolysis of PET.

[0044] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein said one or more non-aromatic polyols are selected from the group of o,co-diols such as but not limited to ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol of average molecular weight of 200-1000 g / mol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol of average molecular weight 200-1000 g / mol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol; cyclic diols such as but not limited to isosorbide and tetrahydrofuran-2,5-dimethanol; branched diols such as but not limited to neopentyl glycol, methyl propanediol, 2-ethyl-l,3-propane- diol, 2,2,4-trimethylpentane-l,3-diol, and any isomers thereof. Most preferably, said non-aromatic polyols comprise diethylene glycol (DEG) and optionally one or more selected from the group comprising isosorbide, trimethylolpropane, glycerol, pentaerythritol, propanediol, butanediol, and polyglycols. Preferably, said polyols are sustainably produced or are bio-based.

[0045] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein said aromatic polyester polyol is obtained from reacting one or more non-aromatic polyols with a mixture of one or more aromatic and non-aromatic compounds. In one embodiment, said one or more non-aromatic polyols are selected from the group comprising, butanediol, polyglycols, glycerol, propanediol, pentaerythritol, trimethylolpropane and isosorbide. In one embodiment, said one or more non-aromatic compounds are selected from the group comprising aliphatic dicarboxylic acids and anhydrides therefrom, such as but not limited to selected from the group consisting of but not limited to: succinic acid, succinic anhydride, itaconic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, citric acid, and dimer fatty acids with a number of carbons from 24-42, preferably the dicarboxylic acid is selected from the group comprising azelaic acid, succinic acid, itaconic acid and / or dimer fatty acid, wherein the dicarboxylic acid is preferably bio-based or sustainably produced, or cor- responding anhydrides thereof, and wherein said aliphatic dicarboxylic acid or anhydride therefrom is preferably bio-based succinic acid, succinic anhydride, itaconic acid, adipic acid or sebacic acid.

[0046] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the aromatic polyester polyols have a weight (w / w) ratio of biobased aromatic compounds to rPET from 10: 1 to 1 : 10, preferably form 5: 1 to 1 :5, and even more preferably from 2: 1 to 1 :2.

[0047] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the weight (w / w) ratio from MPA: FDCA is from 1 :9 to 1 :0, preferably from 3: 1 to 1 :3, even more preferably from 2: 1 to 1 :2, even more preferably from 1.5: 1 to 1 : 1.5.

[0048] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the ratio of the one or more aromatic compounds, preferably MPA, FDCA, and / or rPET to polyol, preferably DEG, is from 2: 1 to 1 :2, preferably from 1.5: 1 to 1 : 1.5, even more preferably from 1.25: 1 to 1 : 1.25, and even more preferably 1 : 1.

[0049] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the acid value of the aromatic polyester polyol is 3.0 mg KOH / g or less, preferably 2.0 mg KOH / g or less, preferably, 1.0 mg or less as measured by ASTM D1980-67.

[0050] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the hydroxyl value is from 180 mg KOH / g to 300 mg KOH / g as measured by ASTM D4274.

[0051] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the undiluted viscosity is 10000 mPa.s at 25°C or less, preferably 9000 mPa.s at 25°C or less, even more preferably 8000 mPa.s at 25°C or less as measured by ISO 3219, and wherein undiluted means before the addition of fire retardants.

[0052] In a preferred embodiment, the present invention provides aromatic polyester polyol according to the first aspect of the invention, wherein the free DEG content of the aromatic polyester polyols of the present invention is 10 wt.% or less, preferably 5 wt.% or less, even more preferably 1 wt.% or less as compared to the total weight of the aromatic polyester polyols. In a second aspect, the present invention provides a process for producing an aromatic polyester polyol, comprising the steps of: i. reacting 3-methyl phthalic anhydride (MPA) with one or more aromatic or nonaromatic polyols, optionally in presence of one or more chain stoppers, and a catalyst at a temperature of 180 °C to 220 °C and distilling off water formed during the reaction; and ii. stepwise raising the temperature to a temperature of approximately 200 °C to 240 °C and maintaining this temperature until the acid value (AV) of the reaction mixture drops below 2 mg KOH / g.

[0053] Preferably, the reaction mixture is purged with nitrogen to create an inert atmosphere and employing mechanical stirring to ensure homogeneity. Optionally, diethylene glycol (DEG) may be added to the cooled polyester polyol to achieve a desired hydroxyl value.

[0054] In one embodiment, 3-methyl phthalic anhydride (MPA) is reacted with one or more aromatic or non-aromatic polyols in presence of one or more chain stoppers, whereby said chain stoppers may be selected from the group comprising mono-functionalized carboxylic acids, such as aliphatic fatty acid compounds, and / or mono-functionalized alcohols, such as ethoxylated surfactants.

[0055] In a third aspect, the present invention provides a polyisocyanurate hard foam obtained by reacting the aromatic polyester polyols of any one of the preceding claims with a diisocyanate, preferably methylene diphenyl diisocyanate (MDI), followed by a trimerization of terminal isocyanate groups to form isocyanuarate groups.

[0056] Polyol

[0057] Many polyols can be used to obtain the aromatic polyester polyols of the invention. A preferred polyol is diethylene glycol (DEG). In one embodiment, the polyol is a mixture of one or more polyol components, said mixture having a diethylene glycol content higher than 95 mol.%. In one embodiment, the polyol is a mixture of one or more polyol components, said mixture having a 1,3-propanediol content higher than 95 mol.%, preferably higher than 98 mol.%.

[0058] The polyol is preferably present in the reaction mixture of aromatic compound and polyol in an amount from 25 wt.% to 80 wt.%, preferably from 30 wt.% to 70 wt.% and even more preferably from 40 wt.% to 50 wt.%, and even more preferably from 45 wt.% to 55 wt.% as compared to the total weight of aromatic compound and polyol. In a particularly preferred embodiment, the polyol is present in an amount from 50 wt.% as compared to the total weight of aromatic compound and polyol in the reaction mixture.

[0059] Weight ratio aromatic compound to polyol

[0060] The weight (w / w) ratio of the aromatic compound in the reaction mixture of aromatic compound and polyol, preferably MPA, FDCA or a mixture thereof to polyol, preferably DEG, is from 2: 1 to 1 :2, preferably from 1.5: 1 to 1 : 1.5, even more preferably from 1.25: 1 to 1 : 1.25.

[0061] The weight ratio aromatic compound to polyol preferably is 1 : 1.

[0062] Aromatic polyester polyols

[0063] The aromatic polyester polyols are obtained by reacting one or more aromatic compounds with one or more non-aromatic polyols, preferably diethylene glycol (DEG), wherein the aromatic compound is biobased 3-methyl phthalic anhydride (MPA) and / or biobased 2,5-furandicarboxylic acid (FDCA), and / or wherein the aromatic compound is chemically recycled polyethylene terephthalate (rPET).

[0064] In a preferred embodiment, the aromatic polyester polyols of the present invention have the following properties:

[0065] ■ Acid Value: 2.0 mg KOH / g or less

[0066] ■ Hydroxyl value: 180 - 300 mg KOH / g

[0067] ■ Functionality: 2.0 - 2.2

[0068] ■ Viscosity diluted: 3000 mPa.s at 25°C or less

[0069] ■ Viscosity not diluted: max 10000 mPa.s at 25°C or less

[0070] ■ Water content: 0.1 wt.% or less

[0071] ■ Free DEG content: 10 wt.% or less

[0072] In a preferred embodiment, the acid value of the aromatic polyester polyol is 3,0 mg KOH / g or less, preferably 2,0 mg KOH / g or less, preferably, 1,0 mg or less as measured by ASTM D1980-67. The polyol is titrated with potassium hydroxide. The acid value is the mass KOH added per gram of polyol. The acid value is a measure of the number of free carboxylic acid groups in the aromatic polyester polyols. In a preferred embodiment, the hydroxyl value is from 180 mg KOH / g to 300 mg KOH / g as measured by ASTM D1957. The aromatic polyester polyols are acylated followed by titration with potassium hydroxide. The hydroxyl value is the mass KOH added per gram of acylated polyol minus the acid number.

[0073] The hydroxyl value is a measure of the total number of free hydroxyl groups in the polyol, mainly determined by start ratio of OH- and COOH-functionalities of the aromatic polyester polyols.

[0074] In a preferred embodiment, the functionality is from 2,0 to 2,2. The functionality is the average number of hydroxyl groups per aromatic polyester polyols. The functionality of the aromatic polyester polyols is a theoretical value based on the number of hydroxyl and acid groups in the raw materials.

[0075] In a preferred embodiment, the diluted viscosity is 3000 mPa.s at 25°C or less, preferably 2500 mPa.s at 25°C or less, even more preferably 2000 mPa.s at 25°C or less as measured by ISO 3219. Diluted means that the aromatic polyester polyol is diluted with a fire retardant. Typically, the fire retardant is added in an amount from 1 to 15 wt.% as compared to the total amount of the aromatic polyester polyols.

[0076] In a preferred embodiment, the undiluted viscosity is 10000 mPa.s at 25°C or less, preferably 9000 mPa.s at 25°C or less, even more preferably 8000 mPa.s at 25°C or less as measured by ISO 3219. Undiluted means that the viscosity of the aromatic polyester polyol measured prior to the addition of further compounds such as fire retardants.

[0077] Both the diluted and the undiluted viscosities are measured for the relationship between the shear stress and the shear rate according to the standard method of 3219 by means of a rotational viscometer with a standard geometry of a spindle in a cup at a defined shear rate and temperature.

[0078] In a preferred embodiment, the water content of the aromatic polyester polyols of the present invention is 0,1 wt.% or less, preferably 0.05 wt.% or less, even more preferably 0.01 wt.% or less as compared to the total weight of the aromatic polyester polyols. The water content is measured by titration of the polyol with Karl Fischer Reagent (a solution of iodine, pyridine, and sulfur dioxide), according to the standard method ASTM D1364-02.

[0079] In a preferred embodiment, the free DEG content of the aromatic polyester polyols of the present invention is 10 wt.% or less, preferably 5 wt.% or less, even more preferably 1 wt.% or less as compared to the total weight of the aromatic polyester polyols. Further compounds

[0080] In a preferred embodiment, further compounds, such as fire retardants, are added to the aromatic polyester polyols of the invention.

[0081] In one embodiment, the composition is free of polyhydroxyalkanoate or lactic acid polyesters.

[0082] In one embodiment, the composition is free of phthalic diacids.

[0083] In one embodiment, the composition is free of compositions with a melting temperature above 75°C.

[0084] PIR foam

[0085] The aromatic polyester polyols of the present invention are useful in PIR. foam production, preferably in PIR foam for insulation board.

[0086] PIR foam is a special type of rigid PU foam. For PIR foams, an aromatic polyester polyol with low functionality and methylene diphenyl diisocyanate (MDI) is required in stochiometric excess of isocyanate. The formation of a PU polymer with terminal isocyanate groups is followed by a trimerization of these terminal isocyanate groups to form isocyanuarate groups.

[0087] In one embodiment, the PIR foam obtained from the aromatic polyester polyols of the present invention have the following characteristics:

[0088] ■ Thermal conductivity (declared) EN 13165: 0,022 W / mK or less

[0089] ■ Reaction to fire EN 13501-1 : E

[0090] ■ Density EN 1602: approx. 30 kg / m3

[0091] ■ Compressive strength at 10% deformation EN 826: min. 150 kPa

[0092] ■ Dimensional stability 70°C / 95%RH EN 1604: max. 2,0 %

[0093] ■ Dimensional stability -20°C EN 1604: max. 1,0 %

[0094] ■ Closed cell content EN ISO 4590: min. 90%

[0095] In a preferred embodiment, the thermal conductivity of the PIR foam obtainable from or comprising the aromatic polyester polyols of the present invention is 0.022 W / mK or less as measured by EN 13165. In a preferred embodiment, the reaction to fire of the PIR foam obtainable from or comprising the aromatic polyester polyols of the present invention is E as measured by EN 13501-1.

[0096] In a preferred embodiment, the density of the PIR. foam obtainable from or comprising the aromatic polyester polyols of the present invention is from 25 kg / m3to 35 kg / m3, and even more preferably is 30 kg / m3as measured by EN 1602.

[0097] In a preferred embodiment, the compressive strength at 10% deformation of the PIR foam obtainable from or comprising the aromatic polyester polyols of the present invention is 150 kPa or more as measured by EN 826.

[0098] In a preferred embodiment, the dimensional stability 70°C / 95%RH of the PIR foam obtainable from or comprising the aromatic polyester polyols of the present invention is 2 or less as measured by EN 1604.

[0099] In a preferred embodiment, the dimensional stability -20°C of the PIR foam obtainable from or comprising the aromatic polyester polyols of the present invention is 1,0 or less as measured by EN 1604.

[0100] In a preferred embodiment, the closed cell content of the PIR foam obtainable from or comprising the aromatic polyester polyols of the present invention is 90 wt.% or more, preferably 95 wt.% or more, even more preferably 97.5 wt.% or more as measured by EN ISO 4590.

[0101] EXAMPLES

[0102] The following examples are intended to further clarify the present invention and it is nowhere intended to limit the scope of the present invention.

[0103] Example 1 - Biobased aromatic compounds

[0104] For the preparation of Example 1.0, a mixture of biobased 3-methylphthalic anhydride (MPA) and biobased 2,5-furandicarboxylic acid (FDCA) in a 1 :9 weight ratio was synthesized. The procedure commenced with the introduction of biobased MPA, biobased FDCA, DEG - in ratio as described in the Table below, chain stoppers, and a catalyst into a four-necked flask equipped with a condenser. The reaction mixture was purged with nitrogen to create an inert atmosphere, and the temperature was monitored using a temperature probe. Mechanical stirring was employed to ensure uniformity within the reaction mixture. Initially, the temperature was elevated to 200 °C and maintained for one hour. Subsequently, the temperature was incrementally raised to 210 °C and sustained for an additional hour. Finally, the temperature was increased to 220 °C and maintained until the acid value (AV) dropped below 2 mg KOH / g. Throughout the process, water formed during the reaction was continuously distilled off. This method ensured the complete reaction of the biobased MPA and FDCA, resulting in a biobased aromatic compound suitable for further applications.

[0105] Examples 1.1 to 1.6 were prepared according to the procedure of Example 1.0 with varying weight ratios of biobased 3-methylphthalic anhydride (MPA) to biobased 2,5- furandicarboxylic acid (FDCA), as depicted in the Table above.

[0106] Example 2-1

[0107] Diethylene glycol (505 g, 4.8 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (487 g, 3 mol), trimethylolpropane (69 g, 0.5 mol), tall oil fatty acid (137 g, 0.5 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After

[0108] 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below

[0109] 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0110] Example 2-2

[0111] Diethylene glycol (550 g, 5.2 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (495 g, 3.1 mol), adipic acid (52 g, 0.4 mol), trimethylolpropane (69 g, 0.5 mol), tall oil fatty acid (63 g, 0.2 mol), isotridecylalcohol-8-polyglycolether (25 g, 0.05 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After

[0112] 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below

[0113] 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0114] Example 2-3

[0115] Diethylene glycol (545 g, 5.1 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (537 g, 3.3 mol), trimethylolpropane (57 g, 0.4 mol), tall oil fatty acid (71 g, 0.2 mol), isotridecylalcohol-8- polyglycolether (36 g, 0.1 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0116] Example 2-4

[0117] Diethylene glycol (594 g, 5.6 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (614 g, 3.1 mol), trimethylolpropane (62 g, 0.5 mol), isotridecylalcohol-8-polyglycolether (77 g, 0.1 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0118] Example 2-5

[0119] Diethylene glycol (697 g, 5.2 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (729 g, 3.1 mol), trimethylolpropane (120 g, 0.9 mol), tall oil fatty acid (100 g, 0.3 mol), isotridecylalcohol- 8-polyglycolether (100 g, 0.2 mol) and titanium(IV) butoxide (4 g, 12 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2.5 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0120] Example 2-6

[0121] Diethylene glycol (283 g, 2.7 mol) and 1,3-propanediol (294 g, 3.9 mol) were added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (597 g, 3.7 mol), adipic acid (73 g, 0.5 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0122] Example 2-7

[0123] Diethylene glycol (594 g, 5.6 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (547 g, 3.4 mol), adipic acid (68 g, 0.5 mol), trimethylolpropane (62 g, 0.5 mol), isotridecylalcohol-8-polyglycolether (77 g, 0.1 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0124] Example 2-8

[0125] Diethylene glycol (648 g, 6.1 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (531 g, 3.3 mol), adipic acid (69 g, 0.5 mol) and titanium(IV) butoxide (3 g, 8 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g.

[0126] Example 2-9

[0127] Diethylene glycol (742 g, 7.0 mol) was added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. Then 3-methylphthalic anhydride (354 g, 2.2 mol), adipic acid (140 g, 1.0 mol), trimethylolpropane (100 g, 0.7 mol), tall oil fatty acid (182 g, 0.6 mol) and titanium(IV) butoxide (4.2 g, 12 mmol) were admitted to the flask. The slurry was heated at 200 °C. The water generated was continuously removed from the reaction mixture by distillation. After 1 hour at 200 °C, the temperature was raised till 220 °C in steps of 10 °C over a period of 1 hour. The reaction mixture was kept at 220 °C until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to 100 °C and 2,5-furandicarboxylic acid (228 g, 1.5 mol) was added. The temperature was raised till 220 °C and kept at this temperature until an acid value below 2 mg KOH / g was reached. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g.

[0128] Example 2-10

[0129] Diethylene glycol (706 g, 6.7 mol), trimethylolpropane (107 g, 0.8 mol) and titanium (IV) butoxide (3 g, 8 mmol) were added to a 4-neck, 2 liters, round bottom flask, fitted with a nitrogen inlet, heating mantle, thermocouple, condenser, and a mechanical stirrer. The mixture was heated at 180 °C and subsequently recycled polyethylene terephthalate pellets (447 g) were added in portions, while further increasing the temperature to 210 °C. The reaction mixture was further heated till 250 °C and kept at this temperature until calculated amount of ethylene glycol and excess of diethylene glycol were distilled. To remove the last part of the excess of diethylene glycol a light vacuum can be applied. The reaction mixture is cooled to 140 °C and 3-methylphthalic anhydride (256 g, 1.6 mol) and tall oil fatty acid (179 g, 0.6) mol were admitted to the flask. The mixture was heated at 220 °C and kept at this temperature until an acid value below 2 mg KOH / g was reached The water generated was continuously removed from the reaction mixture by distillation. The reaction mixture was cooled to room temperature and the hydroxyl value was determined. If needed, extra diethylene glycol was added to the reaction mixture to correct the hydroxyl value to 225 mg KOH / g. The polyol so obtained had the following characteristics:

[0130] Example 3

[0131] Polyol synthesis was performed in a 2-liter, four-necked round-bottom flask equipped with a mechanical stirrer, nitrogen inlet, thermometer, and a condenser. The flask was charged with the specified diols and polyols (e.g., diethyleenglycol (DEG), trimethylolpropane (TMP), 1,3-propanediol (1,3-PDO), 1,5-pentanediol (1,5-PDO), 1,6- hexanediol (1,6-HDO), isosorbide), 3-methyl phthalic anhydride (MPA), aliphatic dicarboxylic acids (e.g., adipic acid, succinic acid, sebacic acid, itaconic acid), and fatty acids (e.g., tall oil fatty acid (TOFA)) and polyoxyethylene-10-nonylphenol (POE-IO- NP). The total mass of the reactants was adjusted to maintain stoichiometric balance, targeting a final hydroxyl functionality between 2.00 and 2.10 and a hydroxyl value between 200 and 250 mg KOH / g. Titanium(IV) butoxide was added as a catalyst.

[0132] The reaction mixture was heated under a nitrogen atmosphere to 200 °C, and water formed during the esterification was continuously removed by distillation. The temperature was gradually increased to 220 °C and maintained until the acid value dropped below 2 mg KOH / g. The mixture was then cooled to 100 °C, and if necessary, additional diol was added to adjust the hydroxyl value to the desired specification. The final product was characterized by its hydroxyl value, acid value, viscosity, aromatic content, and free diethylene glycol (DEG) content.

[0133] Compositions that were successfully prepared are described in the table below:

[0134] Ex Composition Bio-based ° / o Functionality Aromatic ° / o Viscosity

[0135] 3-1 MPA (40.6%) + DEG (42.1%) + TMP 43 2.01 38.58 126.5

[0136] (5.71%) + TOFA (11.4%)

[0137] 3-2 MPA (39.6%), Adipic acid (4.2%)%) 39 2.04 37.87 116.25

[0138] + DEG (44.0%) + TMP (5.0%) +

[0139] TOFA (5.0%) + POE-IO-NP (2.0%)

[0140] 3-3 MPA (43.0%) + DEG (43.6%) + TMP 38 2.02 40.86 186.26

[0141] (4.6%) + TOFA (4.6%) + POE-IO-NP

[0142] (2.9%)

[0143] 3-4 MPA (45.5%) + DEG (44.0%) + TMP 34 2.05 43.17 350.8

[0144] (4.6%) + POE-IO-NP (5.7%)

[0145] 3-5 MPA (41.7%) + DEG (39.8%) + TMP 40 2.05 39.51 148.8

[0146] (6.9%) + TOFA (5.7%) + POE-IO-NP

[0147] (5.7%)

[0148] 3-6 MPA (47.8%) + Adipic acid (5.9%%) 61 2.00 46.16 393.48

[0149] + DEG (22.7%) + 1,3-PDO (23.5%)

[0150] 3-7 MPA (40.5%) + Adipic acid (5.0%) + 35 2.05 38.37 231.8

[0151] DEG (44.0%) + TMP (4.6%) + POE-

[0152] IO-NP (5.7%)

[0153] 3-8 MPA (42.5%) + Adipic acid (5.5%) + 32 2.00 40.75 189.6

[0154] DEG (51.8%)

[0155] 3-9 MPA (37.2) + Adipic acid (4.5%) + 41 2.05 35.47 107.3

[0156] DEG (39.8%) + TMP (6.9%) + TOFA

[0157] (5.7%) + POE-IO-NP (5.7%)

[0158] 3-10 MPA (32.5%) + Adipic acid (9.0%) + 41 2.05 31.32 86.6

[0159] DEG (40.0%) + TMP (6.9%) + TOFA

[0160] (5.7%) + POE-IO-NP (5.7%)

[0161] 3-11 MPA (41.9%) + Adipic acid (11.7%) 62 2.00 40.68 178.8

[0162] + DEG (22.7%) + 1,3-PDO (23.5%)

[0163] 3-12 MPA (39.3%) + Adipic acid (10.0%) 63 2.03 38.11 155.4

[0164] DEG (23.0%) + TMP (4.0%) + TOFA

[0165] (5.0%) + 1,3-PDO (18.5%)

[0166] 3-13 MPA (18.3%) + Adipic acid (10%) + 62 2.01 17.81 59.1

[0167] DEG (30.0%) + TMP (5%) + TOFA

[0168] (5%) + isosorbide (16.5%) -14 MPA (41.3%) + Adipic acid (10.5%) 76 2.02 40.19 227.7

[0169] + DEG (10.0%) + TMP (4.0%) +

[0170] TOFA (5%) + 1,3-PDO (29.0%) -15 MPA (38.3%) + Adipic acid (9.6%) + 78 2.01 37.19 103.9

[0171] DEG (9.2%) + TMP (5.3%) + TOFA

[0172] (10%) + 1,3-PDO (27.4%) -16 MPA (28.0) + Adipic acid (14.2%) + 54 2.00 27.1 152.3

[0173] DEG (34.6%) + TMP (2.0%) + TOFA

[0174] (4%) + isosorbide (17.0%) -17 MPA (39.6%) + Adipic acid (4.9%) + 87 2.00 37.82 97.6

[0175] 1,6-HDO (55.3%) -18 MPA (47.8%) + Adipic acid (6%) + 85 2.00 46.18 309.2

[0176] 1,3-PDO (23.0%) + 1,5-PDO

[0177] (23.0%) -19 MPA (47.1%) + Succinic acid (6.2%) 85 2.00 45.69 407.2

[0178] + 1,3-PDO (23.3%) + 1,5-PDO

[0179] (23.3%) -20 MPA (39.2%) + Succinic acid 87 2.00 38.58 203.1

[0180] (13.3%) + 1,3-PDO (23.7%) + 1,5-

[0181] PDO (23.7%) -21 MPA (39.0%), Adipic acid (13.1%) + 87 2.01 38.21 128.1

[0182] TMP (4.0%) + TOFA (7%) + 1,3-PDO

[0183] (36.7%) -22 MPA (35.2%) + Succinic acid 88 2.00 34.33 86.9

[0184] (12.0%) + 1,5-PDO (52.6%) -23 MPA (43.1%) + Adipic acid (5.5%) 86 2.00 41.35 132.6

[0185] + 1,5-PDO (51.2%) -24 MPA (43.0%) + Succinic acid (5.1%) 86 2.00 41.37 159.2

[0186] + 1,5-PDO (51.7%) -25 MPA (30.3%) + Succinic acid (6.1%) 66 2.02 37.99 108.6

[0187] DEG (20.0%) + TMP (5.7%) + TOFA

[0188] (10%) + 1,3-PDO (18.7%) -26 MPA (36.6%) + Succinic acid (6.2%) 88 2.01 35.53 105.1

[0189] + Sebacic (3.1%) + TMP (5.3%) +

[0190] TOFA (10%) + 1,3-PDO (19.3%) +

[0191] 1,5-PDO (19.3%) -27 MPA (34.5%) + Succinic acid 88 2.00 34.24 131.4

[0192] (17.5%) + 1,3-PDO (23.9%) + 1,5-

[0193] PDO (23.9%) -28 MPA (35.0%) + Succinic acid 88 2.00 35.18 226.5

[0194] (21.1%) + 1,3-PDO (43.7%) 3-29 MPA (24.6%) + Succinic acid 90 2.00 28.22 78.1

[0195] (30.5%) + 1,3-PDO (44.7%)

[0196] 3-30 MPA (24.9%) + Succinic acid 90 2.00 28.24 70.5

[0197] (27.6%) + Itaconic (2.8%) + 1,3-

[0198] PDO (44.5%)

[0199] 3-31 MPA (26.5%) + Succinic acid 91 2.01 26.9 104.9

[0200] (26.5%) + TMP (2.0%) + TOFA (3%)

[0201] + 1,3-PDO (41.8%)

[0202] 3-32 MPA (25.8%) + Succinic acid 91 2.01 26.05 58.1

[0203] (25.8%) + TMP (2.0%) + TOFA (3%)

[0204] + 1,3-PDO (34.6%) + 1,5-PDO

[0205] (8.7%)

[0206] 3-33 MPA (26.9%) + Succinic acid 91 2.00 27.28 n.d.

[0207] (26.9%) + 1,3-PDO (36.8%) + 1,5-

[0208] PDO (9.2%)

[0209] 3-34 MPA (32.6%) + Succinic acid 89 2.00 32.73 n.d.

[0210] (21.7%) + 1,3-PDO (36.4%) + 1,5-

[0211] PDO (9.1%)

[0212] 3-35 MPA (25.6%) + Succinic acid 91 2.10 25.82 n.d.

[0213] (25.6%) + TMP (7.4%) + TOFA (3%)

[0214] + 1,3-PDO (29.7%) + 1,5-PDO

[0215] (7.4%)

[0216] 3-36 MPA (33.0%) + Succinic acid 89 2.02 32.6 n.d.

[0217] (12.7%) + Sebacic acid (5.1%) +

[0218] TMP (4.0%) + TOFA (5%) + 1,3-PDO

[0219] (28.0%) + 1,5-PDO (12.0%)

[0220] 3-37 MPA (35.9%) + Sebacic acid (19.3%) 88 2.03 35.1 n.d.

[0221] + TMP (4.0%) + TOFA (5%) + 1,3-

[0222] PDO (35.5%)

[0223] 3-38 MPA (24.6%) + Succinic acid 91 2.01 24.8 n.d.

[0224] (24.6%) + TMP (4.3%) + TOFA

[0225] (8.0%) + 1,3-PDO (38.4%)

[0226] 3-39 MPA (25.6%) + Succinic acid 91 2.00 25.8 n.d.

[0227] (25.6%) + 1,3-PDO (24.3%) + 1,5-

[0228] PDO (24.3%) n.d. = not determined.

Claims

CLAIMS1. Aromatic polyester polyol obtained from reacting one or more aromatic compounds with one or more non-aromatic polyols, whereby said aromatic compounds comprise 3-methyl phthalic anhydride (MPA).

2. Aromatic polyester polyol according to claim 1 , whereby said 3-methyl phthalic anhydride is biobased.

3. Aromatic polyester polyol according to claim 1 or 2, wherein said aromatic compound further comprises 2,5-furandicarboxylic acid (FDCA), phthalic anhydride (PA) and / or recycled polyethylene terephthalate (rPET).

4. Aromatic polyester polyol according to any of claims 1 to 3, wherein said one or more non-aromatic polyols comprise one or more selected from the group comprising diethylene glycol (DEG), isosorbide, trimethylolpropane, glycerol, pentaerythritol, propanediol, butanediol, pentanediol, hexanediol and polyglycols.

5. Aromatic polyester polyol according to any of claims 1 to 4, wherein the biobased aromatic compounds are derived from plants, animals, algae, fungi, or bacteria, and preferably are plant-based.

6. Aromatic polyester polyol according to any of claims 1 to 5, wherein one or more aromatic compounds are obtained by glycolysis of PET.

7. Aromatic polyester polyol according to any of claims 1 to 6, wherein said aromatic polyester polyol is obtained from reacting one or more non-aromatic polyols with a mixture of one or more aromatic and non-aromatic compounds, whereby said non-aromatic compounds are selected from the group comprising, butanediol, propanediol, polyglycols, glycerol, isosorbide, trimethylolpropane, pentaerythritol and aliphatic dicarboxylic acids, preferably bio-based succinic acid, succinic anhydride, itaconic acid, adipic acid or sebacic acid.

8. Aromatic polyester polyol according to any of claims 1 to 7, wherein the aromatic polyester polyols are hybrid aromatic polyester polyols and wherein the weight (w / w) ratio of biobased aromatic compounds to rPET are from 10:1 to 1 :10.

9. Aromatic polyester polyol according to any of claims 1 to 8, wherein the weight (w / w) ratio from MPA:FDCA is from 1 :9 to 1 :0.

10. Aromatic polyester polyol according to any of claims 1 to 9, wherein the ratio of the one or more aromatic compounds, preferably MPA, FDCA, PA and / or rPET to polyol, preferably DEG, is from 2:1 to 1 :2.

11. Aromatic polyester polyol according to any of claims 1 to 10, wherein the acid value of the aromatic polyester polyol is 3.0 mg KOH / g or less, as measured by ASTM D1980-67.

12. Aromatic polyester polyol according to any of claims 1 to 11 , wherein the hydroxyl value is from 180 mg KOH / g to 300 mg KOH / g as measured by ASTM D4274.13.Aromatic polyester polyol according to any of claims 1 to 12, wherein the undiluted viscosity is 10000 mPa.s at 25°C or less at 25°C or less as measured by ISO 3219, and wherein undiluted means before the addition of fire retardants.

14. Aromatic polyester polyol according to any of claims 1 to 13, wherein the free DEG content of the aromatic polyester polyols of the present invention is 10 wt.% or less, as compared to the total weight of the aromatic polyester polyols.

15. Process for producing an aromatic polyester polyol, comprising the steps of: i. reacting 3-methyl phthalic anhydride (MPA) with one or more non-aromatic polyols, optionally in presence of one or more chain stoppers, and a catalyst at a temperature of 180 °C to 220 °C and distilling off water formed during the reaction; and ii. stepwise raising the temperature to a temperature of approximately 200 °C to 240 °C and maintaining this temperature until the acid value (AV) of the reaction mixture drops below 2 mg KOH / g.

16. A polyisocyanurate hard foam obtained by reacting the aromatic polyester polyols of any of claims 1 to 14 with a diisocyanate followed by a trimerization of terminal isocyanate groups to form isocyanuarate groups.

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