BR112019017619B1 - PROCESS, POLYMER (TRIMETHYLENE FURANDICARBOXYLATE), COPOLYMER AND METHOD TO INCREASE THE RATE OF POLYCONDENSATION - Google Patents

Abstract

The present invention relates to a process comprising the steps: (a) contacting a mixture comprising furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and, optionally, a poly(( alkylene ether), at a temperature in the range of from about 120°C to about 220°C to form the prepolymer, wherein the molar ratio of furandicarboxylic acid dialkyl ester to 1,3- propanediol is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from about 220°C to about 260°C to form the polymer. The mixture from step (a) may further comprise an anthraquinone compound.

Description

CROSS-REFERENCE TO THE RELATED PATENT APPLICATION

[001] The present application claims the priority of the provisional patent application US 1962/462,948, filed on February 24, 2017, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[002] The present invention relates to processes for the production of poly(trimethylene furandicarboxylate) using zinc catalyst.

BACKGROUND OF THE INVENTION

[003] Polyesters are an important class of industrially significant polymers. Polyesters are used in many industries, including apparel, carpeting, packaging films, paints, electronics and transportation. Typically, polyesters are produced by condensing one or more of their diacids or esters with one or more diols, where the starting materials are petroleum derivatives.

[004] Poly(trimethylene furandicarboxylate) (PTF) is an important new polymer, in which the starting materials of furan dicarboxylic acid or an ester thereof and 1,3-propanediol can be produced from the biomass feedstock . Furan dicarboxylic acid (FDCA) can be produced from the oxidation of hydroxymethyl furfural (which is readily available from a variety of sources, e.g. biomass and/or high fructose corn syrup) and 1 ,3-propanediol can be produced by fermenting sugar. Both materials are renewable materials and are starting to be produced in significant quantities from an industrial point of view.

[005] While PTF can be produced from 100% renewable materials, polymer production presents significant challenges. For example, titanium catalysts commonly used in transesterification and polycondensation to produce PTF can also produce impurities that can impart an unwanted yellow color to the PTF.

[006] Processes for preparing PTF that have less color are needed.

SHORT DESCRIPTION OF THE INVENTION

[007] The present invention relates to processes for preparing the polymer of poly(trimethylene furandicarboxylate), the polymer produced through these processes, and a method for increasing the rate of polycondensation in a process for preparing the polymer of poly (trimethylene furandicarboxylate)). Also described are processes for preparing a block copolymer comprising the hard segment of poly(trimethylene furandicarboxylate) and the soft segment of poly(alkylene ether furandicarboxylate), and the copolymer produced by these processes. In one embodiment, a process is described, the process comprising the steps of: (a) contacting a mixture comprising furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and, optionally, a diol of poly(alkylene ether), at a temperature in the range of from about 120°C to about 220°C for prepolymer formation, - wherein the mole ratio of furandycarboxylic acid dialkyl ester to 1 ,3-propanediol is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from about 220°C to about 260°C to form the polymer.

[008] In one embodiment, the furandicarboxylic acid dialkyl ester is 2,5-furandicarboxylate dimethyl ester and the polymer is poly(trimethylene furandicarboxylate). In another embodiment, the mixture of step (a) further comprises an anthraquinone compound represented by Structure A, as described hereinbelow. In yet another embodiment, the zinc compound comprises zinc acetate, zinc acetylacetonate, zinc glycolate, zinc p-toluenesulfonate, zinc carbonate, zinc trifluoroacetate, zinc oxide or zinc nitrate. In another embodiment, the concentration of the zinc compound is in the range of from about 20 ppm to about 300 ppm, based on the total weight of the polymer. In a further embodiment, the mixture in step (a) further comprises a phosphorus compound and the phosphorus compound is present in the mixture in an amount ranging from about 1 ppm to about 50 ppm, based on total weight. of the polymer.

[009] In one embodiment, step (a) of the process is carried out in the absence of a titanium compound. In another embodiment, step (b) of the process is carried out in the absence of a titanium compound. In another embodiment, step (a) and step (b) of the process are carried out in the absence of a titanium compound.

[010] In another embodiment, the process further comprises the step: (c) of crystallizing the polymer of poly(trimethylene furandicarboxylate) obtained from step (b) at a temperature in the range from about 110 °C to about 130 °C to obtain crystallized poly(trimethylene furandicarboxylate) polymer.

[011] In yet another embodiment, the process further comprises the step: (d) polymerization of poly(trimethylene furandicarboxylate) polymer crystallized in the solid state at a temperature below the melting point of the polymer.

[012] In another embodiment, poly(alkylene ether) glycol is present in the mixture of step (a) and the poly(alkylene ether glycol) is selected from the group consisting of poly(alkylene ether) glycol ethylene glycol), poly(1,2-propylene ether), poly(trimethylene ether) glycol, poly(tetramethylene ether) glycol and poly(ethylene-co-tetramethylene ether) glycol, and the polymer is a block copolymer comprising a hard segment of poly(trimethylene furandicarboxylate) and soft segment of poly(alkylene ether furandicarboxylate).

DETAILED DESCRIPTION OF THE INVENTION

[013] All patents, patent applications and publications cited herein are incorporated herein by reference in their entirety.

[014] As used herein, the term "embodiment" or "description" is not intended to be limiting, but generally applies to any of the embodiments defined in the claims or described herein. These terms are used interchangeably in this document.

[015] In the present invention, several terms and abbreviations are used. The following definitions apply unless specifically noted otherwise.

[016] The articles “a”, “a” and “a/o” that precede an element or component are intended to be non-restrictive in relation to the number of cases (that is, occurrences) of the element or component. Accordingly, the articles "a", "a" and "a/o" should be read to include one or at least one, and the singular word form of the element or component also includes the plural, unless the number obviously means the singular.

[017] The term "comprising" means the presence of the declared features, integers, steps or components, as mentioned in the claims, but which does not exclude the presence or addition of one or more other features, integers, steps, components or your groups. The term "comprising" is intended to include the embodiments encompassed by the terms "essentially consisting of" and "consisting of", similarly, the term "essentially consisting of" is intended to include the embodiments encompassed by the term "consisting of".

[018] When present, all ranges are inclusive and combinable. For example, when a range from "1 to 5" is recited, the range recited should be interpreted as including the ranges "1 to 4", "1 to 3", 1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" and so on.

[019] As used herein in relation to a numerical value, the term "about" refers to a range from +/- 0.5 of the numerical value, unless the term is specifically defined otherwise in the context. For example, the phrase "pH value of about 6" refers to pH values from 5.5 to 6.5, unless the pH value is specifically defined otherwise.

[020] Each maximum numerical limitation provided throughout this Specification is expected to include all lower numerical limitations, as if such lower numerical limitations were expressly written herein. Each minimum numerical limitation provided throughout this Specification will include all upper numerical limitations, as if such upper numerical limitations were expressly written herein. Each numerical range provided throughout this Specification will include all narrower numerical ranges that fall within a broader numerical range, as if such narrower numerical ranges were all expressly written herein.

[021] The features and advantages of the present invention will be more easily understood by those skilled in the art by reading the following Detailed Description of the Invention. It should be appreciated that certain features of the present invention which, for clarity, are described above and below in the context of separate embodiments, may also be provided in combination in a single element. Conversely, various features of the present invention which, for brevity, are described in the context of a single embodiment, may also be provided separately or in any subcombination. In addition, references to the singular may also include the plural (for example, "an" and "an" can refer to one or more), unless the context specifies otherwise.

[022] The use of numerical values in the various intervals specified in the present invention, unless expressly indicated otherwise, are expressed as approximations, as if the minimum and maximum values within the stated intervals were both preceded by the term "about" . In this way, small variations above and below the established ranges can be used to achieve substantially the same results as values within the ranges. Furthermore, the description of these ranges is intended as a continuous range, including all values between the minimum and maximum values.

[023] As used herein: The term "poly(trimethylene furandicarboxylate)" or PTF means a polymer comprising the repeating units derived from 1,3-propanediol and furan dicarboxylic acid. In some embodiments, the poly(trimethylene furandicarboxylate) comprises greater than or equal to 95 mol% of repeating units derived from 1,3-propanediol and furan dicarboxylic acid. In yet other embodiments, the mole percentage of 1,3-propanediol repeating units and furan dicarboxylic acid is greater than or equal to 95 or 96 or 97 or 98 or 99 mole %, wherein the mole percentages are with based on the total amount of monomers that form the poly(trimethylene furandicarboxylate). In some embodiments, the furan dicarboxylic acid is 2,3-furan dicarboxylic acid, 2,4-furan dicarboxylic acid, 2,5-furan dicarboxylic acid, or a combination thereof. In other embodiments, the furan dicarboxylic acid is 2,5-furan dicarboxylic acid.

[024] The term "repeating unit of trimethylene furandicarboxylate" means a polymer having as a repeating unit a structure consisting of alternating furandicarboxylate and -CH2CH2CH2O- groups, where the "furandicarboxylate" includes furan-2,3- dicarboxylate, furan-2,4-dicarboxylate, and furan-2,5-dicarboxylate. The molecular weight of this repeating unit is 196 g/mol. The term "trimethylene furan-2,5-dicarboxylate repeating unit" means a polymer having as a repeating unit a structure consisting of alternating furan-2,5-dicarboxylate and -CH2CH2CH2O- groups, according to the Formula (I):

[025] Similarly, the term "repeating unit of trimethylene furan-2,4-dicarboxylate" means a polymer having as a repeating unit a structure consisting of alternating groups of furan-2,4-dicarboxylate and - CH2CH2CH2O-, and the term "repeating unit of trimethylene furan-2,3-dicarboxylate" means a polymer having as a repeating unit a structure consisting of alternating groups of furan-2,3-dicarboxylate and -CH2CH2CH2O-. The value of n (the number of repeating units), for example, could be 10 to 1000, or 50 to 500, or 25 to 185, or 80 to 185.

[026] Depending on the number of repeating units in the polymer, the intrinsic viscosity may vary.

[027] The terms "polymer backbone" and "polymer backbone" are used interchangeably herein and mean that two or more monomeric units covalently bonded together create a continuous polymer chain.

[028] The term "terminal group", as used herein, means a reactive or non-reactive functional group present at an end of the main polymer chain.

[029] The term "dipropanediol" or "di-PDO" repeating unit or terminal group of a polymer means a unit having a structure according to Formula (II): - where P is poly(trimethylene furandicarboxylate) and X is P or hydrogen. The di-PDO group can be a terminal group where X is hydrogen, or the di-PDO group can be a repeating unit in the backbone of the polymer where X is P.

[030] The term "terminal allyl group" means an allyl group at the end of a polymer of poly(trimethylene furandicarboxylate), for example, according to Formula (III): - in which P represents the polymer of poly(trimethylene furandicarboxylate).

[031] The term "terminal alkyl ester group" means an alkyl ester group at the end of a polymer of poly(trimethylene furandicarboxylate). In some embodiments, the alkyl end group can be methyl, ethyl, propyl or butyl.

[032] The term "terminal carboxylic acid groups" means a carboxylic acid group at the end of a polymer of poly(trimethylene furandicarboxylate).

[033] The term "terminal decarboxyl groups" means that the furan ring at the end of a polymer of poly(trimethylene furandicarboxylate) has no carboxylic acid group.

[034] The term "cyclic oligoester" means a cyclic compound composed of two to eight repeating units of a structure, according to Formula (I). The term "cyclic dimer oligoester" means a dimer having a structure according to Formula (IV):

[035] Other cyclic oligoesters include the trimers, tetramers, pentimers, heximers, heptimers and octimers of the repeating unit of Formula (I).

[036] The term "furan dicarboxylic acid" encompasses 2,3-furan dicarboxylic acid; 2,4-furan dicarboxylic acid; and 2,5-furan dicarboxylic acid. In one embodiment, the furan dicarboxylic acid is 2,3-furan dicarboxylic acid. In one embodiment, the furan dicarboxylic acid is 2,4-furan dicarboxylic acid. In one embodiment, the furan dicarboxylic acid is 2,5-furan dicarboxylic acid.

[037] The term "furandicarboxylate dialkyl ester" means a dicarboxylic acid dialkyl ester of furan. In some embodiments, the furandicarboxylate dialkyl ester can have a structure according to Formula (V): - where each R independently is C1-C8 alkyl. In some embodiments, each R independently is methyl, ethyl or propyl. In another embodiment, each R is methyl, and the furan dicarboxylate dialkyl ester is 2,5-furan dicarboxylic dimethyl ester (FDME). In yet another embodiment, each R is ethyl, and the furan dicarboxylate dialkyl ester is 2,5-furan dicarboxylic diethyl ester.

[038] The terms “a* value”, “b* value” and “L* value” mean a color in accordance with the CIE color space L* a* b*. The a* value represents the red color grade (positive values) or the green color grade (negative values). The b* value indicates the degree of yellow color (positive values) or the degree of blue color (negative values). The L* value represents the lightness of the color space, where 0 indicates a black color and 100 refers to a diffused white color. The degree of yellowness of the polymer is also represented by the Yellowness Index (YI) - the higher the YI value, the more yellow the color.

[039] The term "prepolymer" means compounds or oligomers of relatively low molecular weight that have at least one repeating unit of trimethylene furandicarboxylate, bis(1,3-propanediol)furandicarboxylate). Typically, the prepolymer has a molecular weight in the range of from about 196 to about 6000 g/mol. The smallest prepolymer will generally be bis(1,3-propanediol)furandicarboxylate), while the largest can have in the range from 2 to 30 repeating units of trimethylene furandicarboxylate.

[040] As used herein, the term “weight average molecular weight” or “Mw” is calculated as - Mw = ∑NiMi2 / ∑NiMi; where Mi is the molecular weight of a chain and Ni is the number of chains of that molecular weight. Weight average molecular weight can be determined using techniques such as gas chromatography (GC), high pressure liquid chromatography (HPLC) and gel permeation chromatography (GPC).

[041] As used herein, "number average molecular weight" or "Mn" refers to the statistical average molecular weight of all polymer chains in a sample. The number average molecular weight is calculated as Mn = ∑NiMi / ∑Ni, where Mi is the molecular weight of one chain and Ni is the number of chains of that molecular weight. The number average molecular weight of a polymer can be determined by techniques such as gel permeation chromatography, viscometry by means of the (Mark-Houwink equation) and colligative methods such as vapor pressure osmometry, end-group determination or proton NMR.

[042] In some embodiments, the present invention relates to a process comprising the steps: (a) contacting a mixture comprising furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and, optionally , a poly(alkylene ether) diol, at a temperature in the range from about 120°C to about 220°C for forming the prepolymer, wherein the molar ratio of the furandicarboxylic acid dialkyl ester for 1,3-propanediol it is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from about 220°C to about 260°C to form the polymer.

[043] In one embodiment of the process, the furandicarboxylic acid dialkyl ester is the dimethyl ester of 2,5-furandicarboxylate and the polymer is poly(trimethylene furandicarboxylate).

[044] Like other polyesters, the properties of poly(trimethylene-2,5-furandicarboxylate) polymer (PTF) depend on its structure, composition, molecular weight and crystallinity characteristics, for example. In general, the higher the molecular weight, the better the mechanical properties. In the processes described herein for producing high molecular weight poly(trimethylene furandicarboxylate), PTF is prepared in a two-stage melt polymerization that includes direct esterification or ester exchange (transesterification), and temperature polycondensation ( s) higher) than the melting temperature of the terminal polymer. After the polycondensation step, the poly(trimethylene furandicarboxylate) polymer can be crystallized, then polymerized if desired into a solid state at a temperature below the melting point of the polymer.

[045] As described herein, the PTF polymer having an intrinsic viscosity of at least 0.6 dL/g and/or a number average molecular weight of at least 15,000 g/mol is prepared in a process of melt polymerization and without solid state polymerization.

[046] The molecular weight of the PTF polymer can be measured using different techniques, for example, proton NMR that provides the average molecular weight from the end-group analysis, size exclusion chromatography that provides the weighted average molecular weights numerical and intrinsic viscosity. The intrinsic viscosity of the PTF polymer produced according to the described process can be measured through the standard methods, for example as described in the Experimental Section below at present, and can be in the range from 0.6 to 1.20 dL /g. In other embodiments, the intrinsic viscosity can range from 0.70 to 1.00 dL/g, or 0.70 to 0.90 dL/g, or 0.70 to 0.80 dL/g. The number average molecular weight (Mn) of the PTF polymer produced according to the process of the present invention can range from 15,000 to 40,000 g/mol. In other embodiments, the number average molecular weight can range from 15,000 to 30,000 g/mol or 15,000 to 25,000 g/mol. The weight average molecular weight (Mw) of the PTF polymer can range from 30,000 to 80,000 g/mol, or 30,000 to 70,000 g/mol, or 30,000 to 60,000 g/mol.

[047] Differential scanning calorimetry (DSC) shows that the PTF polymer prepared using the melt polymerization process described does not have a melting point when the polymer sample is heated at 10 °C / min, which indicates that the polymer mostly is in amorphous state. For producing a crystallized PTF polymer, the amorphous PTF polymer is heated to the cold crystallization temperature, for example, heating at a temperature in the range from 100 to 130 °C, to obtain a crystallized PTF polymer from from which the melting point can be determined. The melting temperature of the crystallized PTF polymer depends on the molecular structure of the 1-repeating unit and the rate of crystallization and morphology. As the molecular weight of the PTF polymer increases, the rate of crystallization reduces and therefore the melting temperature reduces. The melting temperature (Tm) and enthalpy or heat of fusion (ΔHm) of the formed crystals are measured from heat-cooling cycles and DSC heat. The heat of fusion of pure crystalline polymer is an important parameter that can be used together with the theoretical heat of fusion for 100% crystalline PTF to estimate the degree of crystallinity of the polymer. Percent crystallinity is directly related to many of the key properties exhibited by a semi-crystalline polymer, including: brittleness, toughness, stiffness or modulus, optical clarity, cold creep or flow, barrier resistance (ability to prevent entry or exit of gas) and long-term stability.

[048] The crystallized PTF polymer can have a wide melting temperature range with multiple peaks in DSC when the polymer is heated at 10 °C/min, while a single narrow peak can be obtained when the polymer is heated at a speed very slowly, for example 1 °C/min. The melting temperature of the main peak of the crystallized PTF polymer is measured from the first heating DSC scan and is in the range from 155 to 185°C, preferably from 165 to 185°C. The glass transition temperature of the polymer is taken on the second heating DSC scan at a rate of 10 °C / min and is within the range from 57 to 62 °C.

[049] The physical, mechanical and optical properties of crystalline PTF are strongly dependent on the morphological characteristics of the polymer, for example, the size, shape, perfection, orientation and/or volume fraction of the polymer. Crystallization rates are usually expressed using isothermal crystallization time values (t1/2) in units of minutes or seconds at a specific temperature and can be obtained from DSC experiments. The isothermal crystallization temperatures are between the glass transition temperature (Tg) and the melting point (Tm) of the PTF polymer and can be measured at various temperatures ranging from 70 to 160 °C. The subsequent DSC heating traces after crystallization with isothermal melting can provide information regarding the melting behavior of the polymer. Crystallization half-lives and crystallization rates depend on factors such as crystallization temperature, average molecular weight, molecular weight distribution, polymer chain structure, presence of any comonomer, nucleating agents and plasticizers . The increase in molecular weight in the melt polymerization process reduces the rate of crystallization and therefore the polymer, as prepared from a melt, is mostly amorphous. In general, polymers that have a slow crystallization rate find limited use in engineering and packaging applications.

[050] It is believed that polyesters prepared from melt polymerization processes comprise the cyclic oligomeric esters as an impurity. In the case of poly(ethylene terephthalate), the majority of the cyclic oligomeric ester is the cyclic trimer, normally present at levels of 2 to 4% by weight. In contrast, in the case of poly(trimethylene terephthalate) the major cyclic oligomeric ester species is the cyclic dimer, which may be present in the polymer at 2.5% by weight or greater. Oligomeric cyclic ester impurities can be problematic during polymerization, processing and in end-use applications such as injection molded parts, garment fibers, filaments and films. Decreasing oligomeric cyclic ester concentrations in the polymer could positively impact polymer production, for example, through extended cleaning cycle times during fiber spinning, reduced oligomer bloom of injection molded parts, and reduced color of films.

[051] One way to reduce the content of oligomeric cyclic esters in polyesters such as poly(ethylene terephthalate) and poly(trimethylene terephthalate) is using solid state polymerization. The main cyclic oligoester in the PTF polymer is the cyclic dimer. The total amount of cyclic esters, including the dimer, in the polymer can be determined from proton NMR analysis as described in the Experimental Section.

[052] The polymer poly(trimethylene furandicarboxylate) may comprise terminal groups other than hydroxyl groups, for example, allyl, carboxylic acid, decarboxylic acid, alkyl ester, aldehyde and di-PDO resulting from thermal or thermo-oxidative degradation of polymer chains, other side reactions during melt polymerization conditions, and impurities in the monomer(s). It is desirable to minimize the formation of terminal groups other than hydroxyl groups.

[053] In one embodiment, in step (a) of the process, a mixture consisting of, or essentially consisting of, furandicarboxylic acid dialkyl ester, 1,3-propanediol, optionally a poly(alkylene ether) diol , and a zinc compound is contacted at a temperature ranging from 120 °C to 220 °C to form a prepolymer. By "consisting essentially of" is meant that less than or equal to 1% by weight of other diester, diacid or polyol monomers, other than furan dicarboxylate ester or 1,3-propanediol, are present in the mixture. In other embodiments, the mixture contacted in the first step is free of or essentially free of acid functional components, for example acid functional monomers such as furandicarboxylic acid. As used herein, the term "essentially free of" means that the mixture comprises less than 5% by weight of acid-functional monomers, based on the total weight of monomers in the mixture. In other embodiments, the amount of acid functional monomers is less than 4% or 3% or 2% or 1% or the amount of acid functional monomers is 0%. It has been found that the presence of acids during the polymerization process can cause an increase in color at the terminal poly(trimethylene furandicarboxylate), therefore the amount of acid should be kept as low as possible.

[054] The furandicarboxylic acid dialkyl ester may be any of the known diesters, for example, the furandicarboxylic acid dialkyl esters containing from 1 to 8 carbon atoms in the ester group. The term "furandicarboxylic acid dialkyl ester" is used herein interchangeably with the term "furandicarboxylate dialkyl ester". In some embodiments, the dialkyl furandicarboxylate esters are furandicarboxylate dimethyl ester, furandicarboxylate diethyl ester, furandicarboxylate dipropyl ester, furandicarboxylate dibutyl ester, furandicarboxylate dipentyl ester, furandicarboxylate dihexyl ester, furandicarboxylate diheptyl, furandicarboxylate dioctyl ester or a combination thereof. In other embodiments, the furandicarboxylate dialkyl esters are furandicarboxylate dimethyl ester, furandicarboxylate diethyl ester, or a mixture of furandicarboxylate dimethyl ester and furandicarboxylate diethyl ester. The ester groups of the furandicarboxylate dialkyl esters can be positioned at the 2,3, 2,4 or 2,5 position of the furan ring. In some embodiments, the furandicarboxylate dialkyl ester is the 2,3-furandicarboxylate dialkyl ester; 2,4-furandicarboxylate dialkyl ester; 2,5-furandicarboxylate dialkyl ester; or a mixture thereof. In still other embodiments, the furandicarboxylate dialkyl ester is 2,5-furandicarboxylate dialkyl ester, while in further other embodiments, it is 2,5-furandicarboxylate dimethyl ester.

[055] In the contacting step, the molar ratio of furandicarboxylic acid dialkyl ester to 1,3-propanediol is in the range from 1:1.3 to 1:2.2. In other words, for every 1 mol of furandicarboxylic acid dialkyl ester, at least 1.3 mol and up to 2.2 mol of 1,3-propanediol can be used. In principle, more than 2.2 mol of 1,3-propanediol can be used for every 1 mol of a furandycarboxylic acid dialkyl ester, however, more than 2.2 mol of 1,3-propanediol provides little benefit and may increase the amount of time and energy required to remove at least a portion of the unreacted 1,3-propanediol. In other embodiments, the mole ratio of furandicarboxylic acid dialkyl ester to 1,3-propanediol can range from 1:1.3 to 1:2.1, or from 1:1.3 to 1: 2.0. In yet other embodiments, the ratio of furandicarboxylic acid dialkyl ester to 1,3-propanediol can range from 1:1.4 to 1:1.8 or from 1:1.5 to 1:1 ,8.

[056] A zinc compound is present in the contacting step and functions as a catalyst for transesterification reactions, in which a prepolymer is produced that has a furandicarboxylate moiety within the main polymer chain. The concentration of zinc, as a metal zinc or a cation, in the mixture is in the range from 20 parts per million (ppm) to 300 ppm by weight, based on the weight of the polymer. The weight of the polymer can be calculated based on the mole of furandycarboxylic acid dialkyl ester added, multiplied by the mass of the repeating unit. In other embodiments, the amount of zinc present in the contacting step can be in the range of from 25 to 250 ppm, or from 30 to 200 ppm, or from 20 to 200 ppm, or from 40 to 150 ppm, or from 50 to 100 ppm. Suitable zinc compounds may include, for example, zinc acetate, zinc acetylacetonate, zinc glycolate, zinc p-toluenesulfonate, zinc carbonate, zinc trifluoroacetate, zinc oxide and zinc nitrate. In one embodiment, the zinc compound comprises zinc acetate in anhydrous or hydrated form. In one embodiment, the zinc compound comprises zinc acetylacetonate. In one embodiment, the zinc compound comprises zinc glycolate. In one embodiment, the zinc compound comprises zinc p-toluenesulfonate. In one embodiment, the zinc compound comprises zinc carbonate. In one embodiment, the zinc compound comprises zinc trifluoroacetate. In one embodiment, the zinc compound comprises zinc oxide. In one embodiment, the zinc compound comprises zinc nitrate. The active catalyst as present during the reaction may be different from the compound added to the reaction mixture. Suitable zinc compounds are commercially available or prepared by known methods.

[057] During the contact step, the dialkyl ester of furandicarboxylic acid is transesterified with 1,3-propanediol resulting in the formation of the prepolymer furandicarboxylate of bis(1,3-propanediol) and an alkyl alcohol corresponding to the alcohol of the furandicarboxylic acid starting material ester. For example, when furandicarboxylic acid dimethyl ester is used, methanol is formed in addition to the prepolymer. During step (a) the alkyl alcohol is removed through distillation. The contacting step can be carried out at atmospheric pressure or, in other embodiments, at slightly increased or reduced pressure. The pressure can range from about 0.04 MPa to about 0.4 MPa. The contacting step carried out at a temperature in the range from 120 °C to 220 °C, for example in the range from 150 °C to 220 °C, or from 160 °C to 220 °C, or at 170 °C to 215 °C or from 180 °C to 210 °C or from 190 °C to 210 °C. The time is typically from one hour to several hours, for example, 2, 3, 4, or 5 hours, or any time between 1 hour and 5 hours.

[058] After the transesterification step, the prepolymer is heated under reduced pressure to a temperature ranging from 220 °C to 260 °C for the formation of poly(trimethylene furandicarboxylate) polymer in a polycondensation step catalyzed. The same zinc compound used in the transesterification step can be used as a catalyst in the polycondensation step. The entire amount of zinc compound can be added in full before the transesterification step, or it can be added in two portions, one portion being added before the transesterification step and the other before the polycondensation step. The 1,3-propanediol by-product is removed during the polycondensation step. The temperature is normally in the range from 220 °C to 260 °C, for example, from 225 °C to 255 °C or from 230 °C to 250 °C. The pressure can be less than about one atmosphere to 0.0001 atmospheres. In this step, the prepolymer undergoes polycondensation reactions, increasing the molecular weight of the polymer (as indicated by increasing intrinsic viscosity or melt flow rate) and releasing the 1,3-propanediol. The polycondensation step can be continued at a temperature in the range from 220°C to 260°C for such a time that the intrinsic viscosity of the polymer reaches from about 0.6 to 1.2 dL/g. The time is typically from 1 hour to several hours, for example, 2, 3, 4, 5, 6, 7, 8, 9, or 10 hours, or any time between 1 hour and 10 hours. In one embodiment, the polymer obtained from step (b) has an intrinsic viscosity of at least 0.60 dl/g. Once the desired intrinsic viscosity of the polymer has been reached, the reactor and its contents can be cooled, for example, to room temperature, to obtain the poly(trimethylene furandicarboxylate) polymer.

[059] Steps (a) and (b) of the process can be conducted in batch polymerization reactors, semi-continuous or continuous. The process can be run batchwise, semi-continuously or continuously. The discontinuous polymerization process (esterification, prepolymerization or polycondensation) encompasses raw materials progressing through unit operation/unit operations in a staged manner to produce a terminal product. The continuous polymerization process encompasses the raw materials progressing through unit operation/unit operations in a contiguous manner to produce a terminal product. A process is considered continuous if material is continuously added to a unit during a reaction and the end product is continuously removed after polymerization. The semi-continuous polymerization process comprises a process stage that is batch and a process stage that is continuous. For example, the esterification stage for preparing a prepolymer can be carried out batchwise and the further polymerization stage(s) can be carried out continuously.

[060] The zinc compounds described herein can function as a catalyst in step (a) (transesterification) and also in step (b) (polycondensation) of the processes described herein. In one embodiment, step (a) and step (b) are carried out using a zinc compound as a catalyst. In one embodiment, step (a) and step (b) are carried out using the same zinc compound as the catalyst. In one embodiment, step (a) and step (b) are carried out using only a zinc compound as a catalyst. In one embodiment, step (a) and step (b) are carried out using a zinc compound as a catalyst, and both step (a) and step (b) are carried out without any additional metal catalyst. In one embodiment, step (a) is carried out in the absence of a titanium compound. In another embodiment, step (b) is carried out in the absence of a titanium compound. In yet another embodiment, step (a) and step (b) are carried out in the absence of a titanium compound.

[061] In another embodiment, the mixture of step (a) further comprises an anthraquinone compound represented by Structure A: - wherein each R is independently selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3, SO2NHC6H11, and each Q, Y and Z is independently selected from H, OH, NH2 and NHR', wherein R' is a cyclohexyl or substituted aryl group. In the mixture comprising furandycarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound, and optionally a poly(alkylene ether) diol, one or more anthraquinone compounds may be present in an amount in the range to from about 1 ppm to about 20 ppm, based on total polymer weight. For example, the anthraquinone can be present in the mixture at 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, 10 ppm, 11 ppm, 12 ppm, 13 ppm, 14 ppm, 15 ppm, 16 ppm, 17 ppm, 18 ppm, 19 ppm, or 20 ppm (or any amount in between).

[062] Useful anthraquinone compounds can be obtained commercially. Preferably, the anthraquinone compounds are halogen-free. Examples of anthraquinone compounds represented by Structure A include the following.

[063] Solvent blue 104, also known as 1,4-bis (mesitylamino)anthraquinone or 1,4-bis[(2,4,6-trimethylphenyl)amino anthracene], which has the following structure:

[064] Solvent blue 45, also known as 4,4'-(1,4-anthraquinonylenediimino) bis[N-cyclohexyl-2-mesitylenesulfonamide], which has the following structure:

[065] Solvent blue 97, also known as 1,4-bis[(2,6-diethyl-4-methylphenyl)amino]anthracen-9,10-dione, which has the following structure:

[066] The blue solvent, also known as 1,4-bis[(4-n-butylphenyl)amino-anthracen-9,10-dione, which has the following structure:

[067] The blue solvent 122, also known as N-(4-((9,10-dihydro-4-hydroxy-9,10-dioxo-1-anthryl)amino)phenyl)acetamide, which has the following structure:

[068] The green solvent 28, also known as 1,4-bis[(4-n-butylphenyl)amino-5,8-dihydroxy]anthracen-9,10-dione, which has the following structure:

[069] The red solvent 207, also known as 1,5-bis[(3-methylphenyl)amino]antaracen-9,10-dione, which has the following structure:

[070] The anthraquinone compound can function as a color toner. The polymer color can be adjusted using one or two or more anthraquinone compounds. In some embodiments, the poly(trimethylene furandicarboxylate) polymer has a b* color value of less than 10, for example, less than 3, as determined by spectrocolorimetry. In some embodiments, the L* color value of the poly(trimethylene furandicarboxylate) is greater than 65, for example, greater than 75.

[071] The anthraquinone compound can also function as a co-catalyst with the zinc compound to increase the rate of polycondensation. In one embodiment, a method is described for increasing the rate of polycondensation in a process for preparing polymer of poly(trimethylene furandicarboxylate), the method comprising the steps: (a) of contacting a mixture at a temperature in the range a from about 120°C to about 220°C to form the prepolymer, - wherein the mixture comprises furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and an anthraquinone compound represented by Structure A - wherein each R is independently selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3, SO2NHC6H11, and each Q, Y and Z is independently selected from H, OH, NH2 and NHR', wherein R' is a cyclohexyl or substituted aryl group; - wherein the molar ratio of furandicarboxylic acid dialkyl ester to 1,3-propanediol is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from about 220°C to about 260°C to form the poly(trimethylene furandicarboxylate) polymer.

[072] The substituted aryl group is selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3 and SO2NHC6H11.

[073] Whether or not the mixture in step (a) comprises an anthraquinone compound, in some embodiments of the processes described herein, the mixture in step (a) further comprises a phosphorus compound. The phosphorus concentration can range from about 1 ppm to about 50 ppm, based on the total weight of the polymer. For example, the amount of phosphorus can be 1 ppm, 2 ppm, 3, ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, 10 ppm, 11 ppm, 12 ppm, 13 ppm, 14 ppm, 15 ppm, 16 ppm, 17 ppm, 18 ppm, 19 ppm, 20 ppm, 21 ppm, 22 ppm, 23 ppm, 24 ppm, 25 ppm, 26 ppm, 27 ppm, 28 ppm, 29 ppm, 30 ppm, 31 ppm, 32 ppm, 33 ppm, 34 ppm, 35 ppm, 36 ppm, 37 ppm, 38 ppm, 39 ppm, 40 ppm, 41 ppm, 42 ppm, 43 ppm, 44 ppm, 45 ppm, 47 ppm, 48 ppm , 49 ppm or 50 ppm (or any amount in between). In one embodiment, the amount of phosphorus can be from about 1 ppm to about 25 ppm. In another embodiment, the amount of phosphorus can be from about 1 ppm to about 10 ppm. In yet another embodiment, the amount of phosphorus can be from about 5 ppm to about 20 ppm. In one embodiment, the mixture of step (a) further comprises an anthraquinone compound as described herein and a phosphorus compound. In another embodiment, the mixture from step (a) further comprises a phosphorus compound and no anthraquinone compound.

[074] Suitable phosphorus compounds include phosphoric acid, phosphorous acid, polyphosphoric acid, phosphate esters such as triethyl phosphate, tributyl phosphate, triphenyl phosphate and mixtures thereof. In one embodiment, the phosphorus compound comprises phosphoric acid. Phosphorous compounds are commercially obtainable.

[075] The zinc compound, the anthraquinone compound and the phosphorus compound can be added in any form, for example, as a powder or as a suspension or solution in a solvent such as 1,3-propanediol.

[076] In a further embodiment, the process further comprises step (c) of crystallizing the poly(trimethylene furandicarboxylate) polymer obtained from step (b) at a temperature ranging from about 110 °C to about 130 °C to obtain the crystallized poly(trimethylene furandicarboxylate) polymer. Typical crystallization times can range from about one hour to several hours.

[077] In yet another embodiment, the process further comprises step (d) of polymerization of poly(trimethylene furandicarboxylate) polymer crystallized in the solid state at a temperature below the melting point of the polymer. This step can be performed to obtain the higher molecular weight polymer. Normally, in the solid state polymerization step, pellets, granules, shavings or flakes of crystallized poly(trimethylene furandicarboxylate) are subjected for a certain amount of time to elevated temperatures between 160°C and below the melting temperature of the polymer in a funnel. , a drum dryer, or a vertical tube reactor.

[078] The mixture of step (a) optionally may include a poly(alkylene ether) diol. The number average molecular weight of the poly(alkylene ether) diol can range from about 250 to about 3000 g/mol. In one embodiment, poly(alkylene ether) diol (also known as poly(alkylene ether) glycol or PAEG) is present in the mixture of step (a), and the polymer obtained is a copolymer (also known as copolyester) . The copolymer comprises the (trimethylene furandicarboxylate) and polyether polyol monomer units. An example of a suitable poly(alkylene ether) diol is poly(tetramethylene glycol) (PTMEG).

[079] A copolyester can be prepared through a two-step process, in which a prepolymer is first produced from PDO, PAEG and the dialkyl ester of furandicarboxylic acid, resulting in an oligomer with a moiety 2.5 -furandicarboxylate within the main chain. This intermediate product is preferably an ester composed of two diol monomers (DOP and PAEG) and a furandicarboxylic acid dialkyl ester monomer. Melt polymerization of the prepolymers under the polycondensation conditions described herein provides the copolymer. In the case where PTMEG is used as the polyalkylene ether diol, the resulting copolymer comprises a soft segment of furan-PTMEG and a hard segment of PTF.

[080] Alternatively, a polyester diol having a number average molecular weight in the range from about 250 to about 3,000 g/mol can be used instead of PAEG, and the resulting copolymer comprises a soft segment of furan-polyester diol and a rigid PTF segment. Polyester diol is a reaction product of a dicarboxylic acid and a diol. The polyester diester is preferably produced from the use of diacid and diol of renewable origin, such as succinic acid, furandicarboxylic acid or sebacic acid and the diol is ethylene glycol, 1,3-propanediol, 1,4-butanediol or isosorbide.

[081] The polymer and copolymers obtained through the processes described herein can be formed into films or sheets directly from the polymerization melt. Alternatively, the compositions can be formed into an easily handled format (such as pellets) from the melt which can then be used to form a film or sheet. The sheets can be used, for example, for forming signs, glazing (such as in bus shelters, street lights or recreational vehicles), displays, car lights and thermoforming articles.

[082] Alternatively, articles comprising the compositions described herein are molded articles, which can be prepared by any conventional molding process, such as compression molding, injection molding, extrusion molding, die blow molding, injection blow molding, injection blow molding, extrusion blow molding and the like. Articles may also be formed by combinations of two or more of these processes, such as, for example, when a core formed by compression molding is overmolded by injection molding.

[083] In particular, the polymer and copolymers are suitable for manufacturing: - fibers for clothing or flooring applications; - mono and bi-oriented films, and multilayer films with other polymers; - adhesive or shrink films for use with food; - packaging or thermoformed food containers, in mono and multilayer, such as containers for milk, yogurt, meat, drinks and similar; - of coatings obtained using the extrusion coating or powder coating method on substrates comprising metals not limited to such as stainless steel, carbon steel, aluminum, such coatings may include binders, agents to control flow such as silica, alumina; - multilayer laminates with rigid or flexible supports, such as, for example, paper, plastic, aluminum or metal films; - foamed or semi-foamed spheres for the production of parts obtained through sintering; - foamed and semi-foamed products, including foam blocks formed using pre-expanded articles; and - foam sheets, thermoformed foam sheets and containers made therefrom for use in food packaging.

[084] Non-limiting embodiments of the present invention include: (1) A process comprising the steps: (a) contacting a mixture comprising furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and, optionally, a poly(alkylene ether) diol, at a temperature in the range of from about 120°C to about 220°C for prepolymer formation, - wherein the molar ratio of the ester of furandycarboxylic acid dialkyl to 1,3-propanediol is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from about 220°C to about 260°C to form the polymer, (2) The process according to embodiment 1 wherein the furandicarboxylic acid dialkyl ester is 2,5-furandycarboxylate dimethyl ester and the polymer is poly(trimethylene furandicarboxylate); (3) The process according to embodiment 1 or 2, wherein the zinc compound comprises zinc acetate, zinc acetylacetonate, zinc glycolate, zinc p-toluenesulfonate, zinc carbonate, zinc trifluoroacetate, zinc oxide zinc or zinc nitrate; (4) The process according to embodiments 1, 2 or 3, wherein the concentration of the zinc compound is in the range of from about 20 ppm to about 300 ppm, based on the total weight of the polymer; (5) The process according to embodiments 1, 2, 3 or 4, wherein step (a) is carried out in the absence of a titanium compound; (6) The process according to embodiments 1, 2, 3, 4 or 5, wherein step (b) is carried out in the absence of a titanium compound; (7) The process according to embodiments 1, 2, 3, 4, 5 or 6, wherein step (a) and step (b) are carried out in the absence of a titanium compound; (8) The process according to embodiments 1, 2, 3, 4, 5, 6 or 7, wherein the mixture of step (a) further comprises an anthraquinone compound represented by Structure A: - wherein each R independently is selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3, SO2NHC6H11, and each Q, Y, and Z independently is selected from H, OH, NH2, and NHR', wherein R' is cyclohexyl or substituted aryl; and - wherein the anthraquinone compound is present in the mixture in an amount ranging from about 1 ppm to about 20 ppm, based on the total weight of the polymer; (9) . The process according to embodiments 1, 2, 3, 4, 5, 6, 7 or 8, wherein the anthraquinone compound is 1,4-bis[(2,4,6-trimethylphenyl)amino]anthracene -9,10-dione; (10) The process according to embodiments 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the mixture in step (a) further comprises a phosphorus compound, and wherein the phosphorus is present in the mixture in an amount ranging from about 1 ppm to about 50 ppm, based on the total weight of the polymer; (11) The process according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the polymer obtained from step (b) has an intrinsic viscosity of at least minus 0.60 dL/g; (12) The process, according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, which further comprises the step: (c) of crystallization of the polymer of poly(furandicarboxylate of trimethylene) obtained from step (b) at a temperature ranging from about 110°C to about 130°C to obtain crystallized poly(trimethylene furandicarboxylate) polymer; (13) The process, according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, which further comprises the step: (d) polymerization of the poly (trimethylene furandicarboxylate) crystallized in the solid state at a temperature below the melting point of the polymer; (14) The process according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, wherein the process is batch, semi-continuous or continuous; (15) The process according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, wherein the poly(alkylene ether) glycol is present in the mixture of step (a) and the poly(alkylene glycol ether) is selected from the group consisting of poly(ethylene ether) glycol, poly(1,2-propylene ether) glycol, poly(trimethylene ether) ) glycol, poly(tetramethylene ether) glycol and poly(ethylene co-tetramethylene ether) glycol, and the polymer is a block copolymer comprising the hard segment of poly(trimethylene furandicarboxylate) and the soft segment of poly(alkylene furandicarboxylate ether); (16) Poly(trimethylene furandicarboxylate) polymer obtained through the process according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14; (17) The copolymer comprising the units of poly(trimethylene furandicarboxylate) hard segment and poly(alkylene furandicarboxylate) soft segment, obtained through the process, according to embodiments 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15; (18) A method of increasing the rate of polycondensation in a process for preparing polymer of poly(trimethylene furandicarboxylate), the method comprises the steps: (a) of contacting a mixture at a temperature in the range from about from 120°C to about 220°C for prepolymer formation, - wherein the mixture comprises furandycarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and an anthraquinone compound represented by Structure A: - wherein each R independently is selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3, SO2NHC6H11, and each Q, Y, and Z independently is selected from H, OH, NH2, and NHR', wherein R' is cyclohexyl or substituted aryl; - wherein the molar ratio of furandicarboxylic acid dialkyl ester to 1,3-propanediol is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from about 220°C to about 260°C to form the poly(trimethylene furandicarboxylate) polymer.

EXAMPLES

[085] Unless otherwise noted, all ingredients are available from Sigma-Aldrich Chemical Company, St. Louis, Missouri. Unless otherwise noted, all materials were used as received.

[086] 2,5-furan dicarboxylic dimethyl ester (FDME) was obtained from Sarchem Laboratories Inc, Farmingdale, NJ.

[087] 1,3-propanediol (BioPDO™) was obtained from DuPont Tate & Lyle LLC. The abbreviation “PDO” is used in all examples for this ingredient.

[088] Zinc diacetate (anhydrous), zinc diacetate dihydrate, phosphoric acid (85% solution), cobalt acetate, 1,4-butanediol and tetra-n-butyl titanate (TBT) were obtained from Sigma- Aldrich.

[089] The anthracene compounds of 1,4-bis[(2,4,6-trimethylphenyl)amino]-9,10-dione (commercially available as toner OpticaTM PRT blue-2 global in dispersion) and 3H-naphtho[ 1,2,3-de]quinoline-2,7-dione, 3-methyl-6-[(4-methylphenyl)amino] (commercially available as OpticaTM PRT global red-2 toner dispersion) were obtained from ColorMatrix, Berea Oh.

[090] As used herein, “Comp. Ex. means ”Comparative Example; "Ex." means Example, "ppm" means parts per million, "g" means gram(s); “Kg” means kilogram(s); "mL" means milliliter(s); “min” means minute(s); "H" means hour(s); "mol" means mol(s); “rpm” means revolutions per minute.

TEST METHODS COLOR MEASUREMENT

[091] A Hunter COLORQUEST™ spectrocolorimeter (Reston, Virginia) was used to measure color. Color is measured in terms of the tristimulus color scale, the CIE L* a * b*: the color value (L*) corresponds to the lightness or darkness of a sample, the color value (a*) on a red scale -green and the color value (b*) on a yellow-blue scale. Color values reported are generally for polymers that were crystallized at 110 °C overnight in a vacuum oven. The calculated yellowness index (YI) values from this instrument are also reported.

ISOTHERMAL CRYSTALLIZATION

[092] About 2 to 3 mg of PTF specimens were heated from room temperature to 230 °C at a heating rate of 30 °C / min, held for 3 minutes, and then cooled to 30 °C / min at 0 °C to obtain the amorphous PTF (cooling on the DSC instrument). The rapidly cooled specimens were then rapidly heated to a crystallization temperature of 110°C to 120°C and held for 2 to 4 hours. A single heat experiment was then applied to the crystallized specimen to examine crystallinity.

MOLECULAR WEIGHT THROUGH SIZE EXCLUSION CHROMATOGRAPHY

[093] A size exclusion chromatography (SEC) system, Alliance 2695TM (Waters Corporation, Milford, MA), was provided with a Waters 2414TM differential refractive index detector, a DAWN Heleos multi-angle light scattering photometer (Wyatt Technologies, Santa Barbara, CA) and a VISCOSTAR IITM differential capillary viscometer detector (Wyatt). The software for data acquisition and reduction was Wyatt's ASTRA® version 6.1. Columns used were two Shodex GPC HFIP-806M TM styrene-divinyl benzene columns with an cutoff of 2 x 107 and theoretical plates of 8,000 / 30 cm; and a Shodex GPC HFIP-804M TM styrene-divinyl benzene column with a 2 x 10 5 cutoff and 10,000 / 30 cm theoretical plates.

[094] The specimen was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) containing 0.01 M sodium trifluoroacetate by mixing at room temperature with gentle stirring for four hours, followed by by filtration through a 0.45 µm PTFE filter. The concentration of the solution was about 2 mg/ml.

[095] The data were obtained with the chromatograph set at 35 °C, with a flow rate of 0.5 mL/min. The injection volume was 100 μl. Runtime was 80 min. Data reduction was performed by incorporating data from all three detectors described above. Eight scattering angles were employed with the light scattering detector. No standard for column calibration was involved in data processing. The weight average molecular weight (Mw) of the polymers is reported.

MOLECULAR WEIGHT BY INTRINSIC VISCOSITY

[096] The intrinsic viscosity (IV) was determined using the Equivalent IV method of Goodyear R-103B, using PET T-3, DUPONT™ SELAR® PT-X250 and DUPONT™ SORONA® 2864 as calibration standards in a flow viscometer Forced VISCOTEK® model Y-501C. A 60/40 mixture of phenol / 1,1,2,2-tetrachloroethane was used as a solvent for the polymer. Samples were prepared by adding 0.15 g of resin to 30 mL of solvent mixture and stirring, the mixture was heated to 100°C for 30 minutes, cooled to room temperature for an additional 30 minutes, and the intrinsic viscosity of the solution was measured.

MERGER FLOW INDEX (MFI) OR MERGER FLOW RATE (MFR)

[097] The melt flow index (MFI) is a measure of how many grams of a polymer flow through a matrix in ten minutes. Melt flow rates for dried PTF polymer resins were measured using a melt flow apparatus (Extrusion Plastometer, Tinium Olsen, Willow Grove, PA) at 210°C with a load of 2160 g, according to ASTM D1238 standard. A correlation between MFR and IV has been established for PTF polymer resins of varying molecular weights.

QUANTIFICATION OF NUMERICAL AVERAGE MOLECULAR WEIGHT (MN) AND QUANTIFICATION OF TERMINAL GROUP BY 1H NMR (PROTON)

[098] 1H NMR spectra were collected using a 700 MHz NMR on samples of about 55 mg in 0.7 mL of 1,1,2,2-tetrachloroethane-d2 (tce-d2) at 110 °C using an acquisition time of 4.68 s, a pulse of 90 degrees and a recycle delay of 30 seconds and an average of 16 transients.

1H NMR CALCULATION METHODS

[099] The samples were integrated and the percentage in mol calculated as is standard in the state of the art. Peak assignments for the PTF polymer are shown below in Table 1. TABLE 1

METHOD FOR DETERMINING THE TOTAL QUANTITY OF CYCLIC DIMERIC ESTERS IN POLY(TRIMETHYLENE-2,5-FURANDICARBOXYLATE) BY 1H NMR

[100] As shown in Table 1, the cyclic dimer furan ring hydrogens (δ 6.89) and the PTF polymer furan ring hydrogens (δ 7.2) have different chemical shifts. The percentage by weight of the cyclic dimer was calculated using the following equations: - Molecular weight of cyclic dimer = (nI of hydrogens of the furan ring of cyclic dimer * 392) / (sum of nI of the polymer terminals); - % cyclic dimer weight = (Molecular weight of cyclic dimer * 100) / (sum of molecular weights of polymer and cyclic dimer); - nI = normalized integral value.

EXAMPLE 1 POLYTRIMETHYLENE 2,5-FURANDYCARBOXYLATE PREPOLYMER (PTF) PREPARED USING ZINC CATALYST

[101] The following amounts of the ingredients were charged into a 3-L three-neck glass reactor equipped with a nitrogen inlet, a condenser, and a mechanical stirrer: 2,5-furandicarboxylate dimethyl ester (FDME) (1, 41 kg, 7.64 mol) and 1,3-propanediol (0.873 kg, 11.47 mol). The molar ratio of DOP to FDME was 1.5. The flask was placed in a metal bath that was preheated to a temperature of 160 °C. The reaction mixture was agitated using the Ekato Paravisc impeller at 100 rpm for 10 minutes to obtain a homogeneous solution under a nitrogen atmosphere. Anhydrous zinc diacetate (0.779 g; 185 ppm zinc based on polymer weight) was added to the mixture at this set temperature. The temperature of the metal bath was adjusted to 170 °C to initiate the transesterification reaction and the first drop of collected condensed distillate was noted as the start of the reaction (zero time). The reaction was continued at this temperature for 30 min, the temperature was increased to 190 °C and the reaction was continued for an additional 30 min. By this time, most of the distillate (about 545 mL) has collected and the distillation rate has been reduced at this point, indicating that the reaction is nearly complete. The transesterification time was recorded from the time the first drop of methanol distillate was observed to the point at which the theoretical amount of methanol distillate was collected. A vacuum ramp was initiated by stopping the nitrogen purge. The pressure was gradually reduced from atmospheric pressure to a final low pressure of about 0.2 mm Hg to 0.4 mm Hg absolute over a period of 1 to 1.5 h, during which time most of the excess 1.3 -propanediol was collected in a trap. At this stage, the pressure in the flask was brought back to atmospheric pressure under flowing nitrogen and removing the flask from the metal bath. The vial was cooled to room temperature and the prepolymer from the vial was recovered.

[102] The recovered prepolymer was analyzed by proton NMR and the properties of the prepolymer are listed in Table 2.

COMPARATIVE EXAMPLE TO POLYTRIMETHYLENE 2,5-FURANDYCARBOXYLATE PREPOLYMER (PTF) PREPARED USING THE TITANIUM CATALYST

[103] The PTF prepolymer was prepared as described in Example 1 but using TBT as catalyst and process conditions as reported in Table 2. TABLE 2

[104] The properties of the PTF prepolymer of Example 1 indicate that the zinc catalyst is a very effective transesterification catalyst relative to the titanium catalyst used for preparing the PTF prepolymer of Comparative Example A. A. reaction was faster at milder temperatures. The amount of methyl ester end groups in the prepolymer of Example 1 was less than that of Comparative Example A and probably could be further reduced by optimizing the molar ratio, the amount of catalyst and the temperature and time of transesterification. The color of the prepolymer, as indicated by CIE L* and b*, was significantly better than that of the prepolymer produced using the titanium catalyst.

EXAMPLE 2 POLYTRIMETHYLENE 2,5-FURANDYCARBOXYLATE POLYMER (PTF)

[105] The following amounts of ingredients were charged into a 3-L three-neck glass reactor: 2,5-furandycarboxylate dimethyl ester (FDME) (1.41 kg, 7.64 mol) and 1,3- propanediol (0.873 kg, 11.47 mol). The molar ratio of DOP to FDME was 1.5. The flask was placed in a metal bath that was preheated to a temperature of 160 °C. The reaction mixture was agitated using the Ekato Paravisc impeller at 100 rpm for 10 minutes to obtain a homogeneous solution under a nitrogen atmosphere. Zinc diacetate dihydrate (0.61 g; 130 ppm zinc based on polymer weight) was added to the mixture at this set temperature. The temperature of the metal bath was adjusted to 170 °C to initiate the transesterification reaction and the first drop of collected condensed distillate was noted as the start of the reaction (zero time). The reaction was continued at this temperature for 30 minutes and then the temperature was increased to 190 °C gradually and the reaction was continued for an additional 35 minutes. By this time, most of the distillate (about 545 mL) has collected and the distillation rate has been reduced at this point, indicating that the reaction is nearly complete.

[106] A vacuum ramp was initiated by stopping the nitrogen purge. The pressure was gradually reduced from atmospheric pressure to a final low pressure of 0.2 mm Hg to 0.4 mm Hg absolute over a period of 1 to 1.5 h, during which time most of the excess 1,3-propanediol was collected in a trap. The temperature of the metal bath was increased to 240 °C and the polycondensation reaction was continued under these conditions for 2 to 4 hours. During this time, the increase in engine torque was monitored as the molecular weight of the polymer built up, and the mixing speed was gradually reduced. Whenever the torque value in milli volts (mV) reached 60 mV, the stirring speed was reduced from 100 to 80, then to 60, then to 40, then to 20 rpm. When there was no rapid increase in the torque value observed at 20 rpm, the reaction was terminated by increasing the pressure to atmospheric pressure under nitrogen flow and removing the flask from the metal bath. The vial was cooled to room temperature and the solid polymer in the vial was recovered.

[107] The recovered polymer was dried and crystallized at 110 to 120 °C overnight in a vacuum oven. The terminal polymer properties are reported in Table 3.

EXAMPLE 3

[108] The polymer was prepared as described in Example 2 using zinc acetate (anhydrous) and cobalt acetate catalysts. The conditions and properties of the polymer process are reported in Table 3.

EXAMPLE 4

[109] The polymer was prepared as described in Example 2, except that the polycondensation reaction was conducted in the presence of anhydrous zinc acetate and 1,4-bis[(2,4,6-trimethylphenyl)amino] color toners anthracen-9,10-dione (“PRT blue-2”) and 3H-naphtho[1,2,3-de]quinolin-2,7-dione, 3-methyl-6-[(4-methylphenyl)amino] (“PRT red-2”) that were added after the transesterification step. The conditions and properties of the polymer process are reported in Table 3.

EXAMPLE 5

[110] The polymer was prepared as described in Example 2, except that the polycondensation reaction was conducted in the presence of anhydrous zinc acetate and phosphoric acid. Phosphoric acid was added after the transesterification step. The conditions and properties of the polymer process are reported in Table 3.

EXAMPLE 6

[111] The polymer was prepared as described in Example 2, except that the polycondensation reaction was conducted in the presence of zinc acetate dihydrate, the blue and red anthraquinone compounds, and phosphoric acid. The anthraquinone and phosphorus compounds were added after the transesterification step. The conditions and properties of the polymer process are reported in Table 3.

COMPARATIVE EXAMPLE B

[112] The PTF polymer was prepared as described in Example 2 using tetrabutyl titanate catalyst and the conditions and process properties of the polymer are reported in Table 3. TABLE 3

[113] The data in Table 3 clearly indicate that the zinc catalyst by itself is a very effective polymerization catalyst for the PTF polymer (Example 2) without any other polymerization catalyst. When compared to titanium catalyst (Ex Comp B), which is the most effective polymerization catalyst known for polyester, zinc catalyst for PTF polymer is even more effective than titanium. Despite the lower transesterification temperature, and the time of transesterification and polycondensation, the molecular weight of the polymer is higher (16,610 versus 15,080) indicating a superior activity of the zinc catalyst compared to titanium. In addition, the crystallized PTF polymer obtained using a zinc catalyst has better color than a polymer based on titanium catalyst, since the whiteness (L*) of the polymer is higher by more than 6 units and the yellowness ( b*) is less than 5 units.

[114] The color results obtained for the polymer in Example 3 are surprising, since the conventional cobalt toner is one of the most used toners to mask the yellow color of the PET polymer; however, in Example 3, the cobalt catalyst had no significant impact on the yellow color of the PTF polymer when compared to the polymer in Example 2. The use of a mixed catalyst system resulted in a polymer that has a molecular weight slightly higher.

[115] Examples 4 to 6 demonstrate the effectiveness of the zinc catalyst in the presence of toners and phosphorus compounds: the color toners helped to reduce the polycondensation time and the phosphorus further enhanced the color of the polymer.

COMPARATIVE EXAMPLE C

[116] In an attempt to produce polybutylene furandicarboxylate using zinc acetate, the transesterification reaction was performed as described in Example 1 with the following amounts of ingredients: FDME (1300 g; 7.05 mol), BDO (952, 8 g; 10.59 mol), and anhydrous zinc acetate (120 ppm) for 90 min at 170 to 210 °C. A total of 915 mL of distillate was collected instead of 571 mL, which is the theoretical amount of methanol distilled. The distillate was analyzed by proton NMR and found to contain 52.8% by weight of methanol, 41.4% by weight of tetrahydrofuran, 4.2% by weight of 1,4-butanediol and 1.6% by weight of FDME. This example illustrates the ineffectiveness of zinc acetate as a catalyst in the polymer synthesis of poly(butylene 2,5-furandicarboxylate) from FDME and BDO.

Claims (19)

1. PROCESS, characterized in that it comprises the steps: (a) bringing into contact a mixture comprising furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound and, optionally, a poly(alkylene ether) diol , at a temperature in the range from 120°C to 220°C for forming the prepolymer, wherein the molar ratio of furandycarboxylic acid dialkyl ester to 1,3-propanediol is in the range from 1 :1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from 220°C to 260°C to form a polymer. 2. Process according to claim 1, characterized in that the dialkyl ester of furandicarboxylic acid is the dimethyl ester of 2,5-furandicarboxylate acid and the polymer is poly(trimethylene furandicarboxylate). 3. Process according to claim 1, characterized in that the zinc compound comprises zinc acetate, zinc acetylacetonate, zinc glycolate, zinc p-toluenesulfonate, zinc carbonate, zinc trifluoroacetate, zinc oxide or zinc nitrate. zinc. 4. Process, according to claim 1, characterized by the concentration of the zinc compound being in the range from 20 ppm to 300 ppm, based on the total weight of the polymer. 5. Process according to claim 1, characterized in that step (a) is carried out in the absence of a titanium compound. 6. Process according to claim 1, characterized in that step (b) is carried out in the absence of a titanium compound. 7. Process according to claim 1, characterized in that step (a) and step (b) are carried out in the absence of a titanium compound. 8. Process according to claim 1, characterized in that the mixture of step (a) further comprises an anthraquinone compound represented by Structure A: wherein each R is independently selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3, SO2NHC6H11, and Q, Y, and Z are each independently selected from H, OH, NH2, and NHR', wherein R' is cyclohexyl or substituted aryl; and wherein the anthraquinone compound is present in the mixture in an amount ranging from 1 ppm to 20 ppm, based on the total weight of the polymer. 9. Process according to claim 8, characterized in that the anthraquinone compound is 1,4-bis[(2,4,6-trimethylphenyl)amino]anthracen-9,10-dione. 10. Process according to claim 8, characterized by the mixture in step (a) further comprising a phosphorus compound, and wherein the phosphorus is present in the mixture in an amount ranging from 1 ppm to 50 ppm, with based on the total weight of the polymer. 11. Process according to claim 1, characterized by the mixture in step (a) further comprising a phosphorus compound, and wherein the phosphorus is present in the mixture in an amount ranging from 1 ppm to 50 ppm, with based on the total weight of the polymer. 12. Process according to claim 1, characterized in that the polymer obtained from step (b) has an intrinsic viscosity of at least 0.60 dL/g. 13. Process according to claim 1, characterized in that it further comprises the step: (c) crystallizing the poly(trimethylene furandicarboxylate) polymer obtained from step (b) at a temperature in the range from 110 °C to 130 °C to obtain the crystallized poly(trimethylene furandicarboxylate) polymer. 14. Process according to claim 13, characterized in that it further comprises the step: (d) polymerizing the crystallized poly(trimethylene furandicarboxylate) polymer in the solid state at a temperature below the melting point of the polymer. 15. PROCESS, according to claim 1, characterized by the process being discontinuous, semi-continuous or continuous. 16. POLYMER OF POLY(FURANDICARBOXYLATE OF TRIMETHYLENE), characterized in that it is obtained from the process, as defined in claim 1. 17. Process according to claim 1, characterized in that the poly(alkylene ether) glycol is present in the mixture of step (a) and the poly(alkyl ether glycol) is selected from the group consisting of poly(ether glycol) of ethylene), poly(1,2-propylene ether) glycol, poly(trimethylene ether) glycol, poly(tetramethylene ether) and poly(ethylene-co-tetramethylene ether) glycol, and the polymer is a block copolymer comprising a hard segment of poly(trimethylene furandicarboxylate) and a soft segment of poly(alkylene ether furandicarboxylate). 18. COPOLYMER, characterized in that it comprises units of a rigid segment of poly(trimethylene furandicarboxylate) and a soft segment of poly(alkylene ether furandicarboxylate), obtained from the process as defined in claim 17. 19. METHOD TO INCREASE THE POLYCONDENSATION RATE IN A PROCESS FOR THE PREPARATION OF POLYMER (TRIMETHYLENE FURANDYCARBOXYLATE), characterized by comprising the steps: (a) contacting a mixture at a temperature in the range from 140 °C at 220°C to form the prepolymer, wherein the mixture comprises furandicarboxylic acid dialkyl ester, 1,3-propanediol, a zinc compound, and an anthraquinone compound represented by Structure A wherein each R independently is selected from the group consisting of H, OH, C1-C6 alkyl, NHCOCH3, SO2NHC6H11, and each Q, Y, and Z independently is a selected from H, OH, NH2, and NHR ', wherein R' is cyclohexyl or substituted aryl; wherein the molar ratio of furandicarboxylic acid dialkyl ester to 1,3-propanediol is in the range from 1:1.3 to 1:2.2; and (b) heating the prepolymer under reduced pressure to a temperature in the range of from 220°C to 260°C to form the poly(trimethylene furandicarboxylate) polymer.