TECHNICAL FIELD

[0001] The present disclosure relates to production of copolyesters.

BACKGROUND

[0002] Pharmaceutical, beverage, and many other containers are conventionally prepared from polymers, such as polyethylene, polyethylene terephthalate (“PET”), polycarbonate, polypropylene (“PP”), and polystyrene. However, there is ongoing concern about the use of plastics in consumer food packaging, including concern about environmental impact.

[0003] As renewable and sustainable bio-based polyester monomers become commercially available, there is increasing demand in the polyester resin market to incorporate the bio-based monomers into existing resins.

[0004] Thus, there is a need in the art for polymeric materials that incorporate bio-based monomers.

SUMMARY

[0005] In an example, the present disclosure provides a copolyester, including: from about 0.5 mol% to about 2 mol% of 2, 5 -furandicarboxylic acid monomer units; and from about 3 mol% to about 4 mol% of diethylene glycol units; wherein the copolyester is formed by esterification and polycondensation reactions including an aromatic or aliphatic dicarboxylic acid, 2,5- furandicarboxylic acid, and ethylene glycol.

[0006] In certain examples, the copolyester may include from about 0.7 mol% to about 1.5 mol% of 2,5-furandicarboxylic acid monomer units.

[0007] In certain examples, the dicarboxylic acid may be terephthalic acid.

[0008] In certain examples, the copolyester may include from about 0.5 mol% to about 3.8 mol% of diethylene glycol units.

[0009] In certain examples, the copolyester may have an intrinsic viscosity above about 0.6 dL/g at 30°C.

[0010] In certain examples, the copolyester may have an intrinsic viscosity above about 0.7 dL/g at 30°C.

[0011] In certain examples, the copolyester may have an intrinsic viscosity above about 0.8 dL/g at 30°C. [0012] In certain examples, the copolyester may have a crystallinity of from about 3 wt% to about 70 wt%.

[0013] In certain examples the copolyester may have a crystallinity of at least about 10 wt%. [0014] In certain examples, the copolyester may have a crystallinity of at least about 20 wt%. [0015] In certain examples, the copolyester may have a crystallinity of at least about 25 wt%. [0016] In certain examples, the copolyester may have a crystallinity of at least about 35 wt%. [0017] In certain examples, no ethylene glycol is added to the esterification or polycondensation reactions.

[0018] In certain examples, a preform may include the copolyester.

[0019] In certain examples, a container may include the copolyester or the preform.

[0020] In certain examples, a fiber may include the copolyester.

[0021] In certain examples, a film may include the copolyester.

[0022] In certain examples, a sheet may include the copolyester.

[0023] In certain examples, a molded article may include the copolyester.

[0024] In certain examples, a method of producing the copolyester may include: esterifying the aromatic or aliphatic dicarboxylic acid and ethylene glycol in the presence of the 2,5- furandicarboxylic acid at a suitable esterifying temperature to produce esterification products; and polycondensing the esterification products at a suitable polycondensing temperature to produce the copolyester.

[0025] In certain examples, an ethylene glycol molar excess of the esterifying may be 120 - 200% of a total dicarboxylic acid charge of the dicarboxylic acid and the 2,5-furandicarboxylic acid.

[0026] In certain examples, the esterifying may be in the presence of a catalyst, a stabilizer, a bluing agent, and/or a suppressant.

[0027] In certain examples, the catalyst may include antimony trioxide.

[0028] In certain examples, the stabilizer may include phosphoric acid.

[0029] In certain examples, the bluing agent may include cobalt acetate tetrahydrate.

[0030] In certain examples, the suppressant may include tetraalkylammonium hydroxide.

[0031] In certain examples, the suppressant may include tetramethylammonium hydroxide and/or tetraethylammonium hydroxide.

[0032] In certain examples, the suitable esterifying temperature may be from 180°C to 300°C. [0033] In certain examples, the suitable esterifying temperature may be from 180°C to 270°C. [0034] In certain examples, the suitable polycondensing temperature may be from 200°C to 300°C.

[0035] In certain examples, the suitable polycondensing temperature may be from 270°C to 290°C.

[0036] In certain examples, a method of producing the preform may include injection-molding the copolyester to produce the preform.

[0037] In certain examples, a method of producing the container may include reheat stretch blow-molding the preform to produce the container.

[0038] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0039] In order that the present disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings. The components in the figures are not necessarily to scale. Moreover, in the figures, like-referenced numerals designate corresponding parts through the different views.

[0040] FIG. 1 illustrates a graph demonstrating variation in differential scanning calorimetry (“DSC”) crystallinity with the amount of FDCA in the reactor feed, and the computed average ethylene terephthalate (“ET”) sequence length;

[0041] FIG. 2 illustrates a graph demonstrating an increase in in-chain diethylene glycol (“DEG”) (mol %) as a function of the amount of FDCA (mol %) in the batch reactor feed;

[0042] FIG. 3 illustrates a graph demonstrating average ET sequence length calculated for FDCA and DEG, when FDCA and DEG are located randomly, and when DEG formation is strongly correlated with attachment to a FDCA unit;

[0043] FIG. 4 illustrates a graph demonstrating the correlation of copolyester furandicarboxylate content with FDCA addition to the polycondensation reactor;

[0044] FIG. 5 illustrates DEG formation (mol %) in PETF copolyesters as a function of FDCA addition (mol %, dicarboxylic acid basis) to the reactor and various batch reactor scales;

[0045] FIG. 6 illustrates computed average ET run lengths for random and non-random DEG formation as a function of FDCA addition (mol %) to the reactor;

[0046] FIG. 7 illustrates PETF peak melting temperature as a function of FDCA addition (mol %) to the reactor for different reactor batch sizes; [0047] FIG. 8 illustrates PETF peak melting temperature as a function of furandicarboxylate content (mol %) for different reactor batch sizes;

[0048] FIG. 9 illustrates PETF peak melting temperature as a function of DEG formation (mol %) for different reactor batch sizes;

[0049] FIG. 10 illustrates PETF peak melting temperature as a function of total monomer unit content (furandicarboxylate or furandicarboxylate plus DEG) for different PETF copolyester reactor batch sizes;

[0050] FIG. 11 illustrates PETF peak melting temperature as a function of MAX(furandicarboxylate or FDCA added, DEG) comonomer unit content for different PETF copolyester reactor batch sizes;

[0051] FIG. 12 illustrates crystallization induction time for non-isothermal crystallization from glass (cold crystallization) as a function of heating rate (°C/min) and the various PETF copolyesters shown;

[0052] FIG. 13 illustrates crystallization half-time for non-isothermal crystallization from glass (cold crystallization) as a function of heating rate (°C/min) and the various PETF copolyesters shown;

[0053] FIG. 14 illustrates DSC crystallinity developed during non-isothermal crystallization from the glass (cold crystallization) as a function of heating rate (°C/min) for PET and the various PETF copolyesters shown;

[0054] FIG. 15 illustrates DSC crystallization induction time for non-isothermal crystallization during the melt cooling (melt crystallization) as a function of cooling rate (°C/min) for PET and the various PETF copolyesters shown;

[0055] FIG. 16 illustrates crystallization half-time for non-isothermal crystallization from the melt cooling (melt crystallization) as a function of cooling rate (°C/min) for PET and the various PETF copolyesters shown;

[0056] FIG. 17 illustrates DSC crystallinity developed during non-isothermal crystallization from the melt cooling (melt crystallization) as a function of cooling rate (°C/min) for PET and the various PETF copolyesters shown;

[0057] FIG. 18 illustrates the natural draw ratio (“NDR”) for PET and PETF copolyester of freeblown, injection-molded preforms produced with 0 to 6 mol % FDCA (dicarboxylic acid basis) in the batch reactor feed;

[0058] FIG. 19 illustrates correspondence between the NDRs measured at low (85 bar/s) and high (550 bar/s) inflation rates; [0059] FIG. 20 illustrates an exploded view of FIG. 19 in the range between 2.2 < NDRio < 2.4 and 2.0 < NDRhi < 2.8;

[0060] FIG. 21 illustrates relative (PET) caustic stress crack resistance (“CSCR”) average failure time as a function of FDCA added to the reactor for PET control (0 mol % FDCA) and PETF copolyesters having 1, 2, 3, 4, and 6 mol % FDCA addition;

[0061] FIG. 22 illustrates FIG. 21 CSCR data for “Example 1” bottles superimposed with the data for “Example 2” bottles, with confidence intervals (95%) shown for both data sets;

[0062] FIG. 23 illustrates coefficients of variation for CSCR failure times for “Example 1” bottles (open circles) and “Example 2” bottles (open triangles);

[0063] FIG. 24 illustrates variation in the thickness-normalized burst pressure of the bottles produced with different low-PETF copolyesters including between 0 and 6 mol % FDCA addition;

[0064] FIG. 25 illustrates volume expansion at 13 seconds following the commencement of the bottle burst test as a function of FDCA addition (mol %) to the reactor; and

[0065] FIG. 26 illustrates fill point drop following carbonation and bottle filling as a function of FDCA addition (mol %) to the reactor.

[0066] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0067] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0068] In an example, the present disclosure provides bio-based copolymers (“PETF”) of polyethylene terephthalate (“PET”) and polyethylene furandicarboxylate (“PEF”), in which diethylene glycol (“DEG”) units are formed. The structures of PET, PEF, PETF, and DEG are as follows: polyethylene terephthalate (PET); polyethylene 2,5-furandicarboxylate (PEF); diethylene glycol (DEG).

[0069] In an example, the present disclosure provides methods and systems to produce PETF copolymers including DEG monomer units. In certain examples, no diethylene glycol is added to the esterification or polycondensation reaction mixtures to produce the PETF copolymers including DEG monomer units.

[0070] In an example, the present disclosure provides copolyesters including low levels of biobased 2,5-furandicarboxylic acid (“FDCA,” also referred to as “furanoic acid”) with terephthalic acid (“TP A”) and ethylene glycol, which offer significant property improvements over corresponding copolyesters modified with isophthalic acid (“IPA”). As copolyester monomers, FDCA and IPA may impart different chain mobility characteristics. FDCA increases the copolyester glass transition temperature (T _g ), whereas IPA decreases the copolyester T _g . The furandicarboxylate co-unit may co-crystallize with the terephthalate counit throughout the PET-PETF-PEFT-PEF composition range, but the isophthalate copolyester does not crystallize beyond an isophthalate addition of about 20 mol %.

[0071] The structures of terephthalic acid (TPA) and isophthalic acid (IPA) are as follows: terephthalic acid (TPA); isophthalic acid (IPA). [0072] As described herein, FDCA-modified copolyesters including FDCA in the 0.5 mol % to 2.0 mol % range advantageously and surprisingly demonstrate enhancement of physical properties for molded and oriented articles. In an example, the enhancements may be related to how the copolyesters incorporate DEG into the polymer chain as a function of FDCA in the reactor feed.

[0073] Surprising melting and crystallization behavior has been observed in copolyesters modified with 2,5-furandicarboxylic acid (FDCA) (low-PETF copolyesters) in the composition range below about 2 mol% furandicarboxylate co-unit incorporation. Further, a synergy between furandicarboxylate addition and DEG insertion as a polymerization defect has been demonstrated to be responsible for the remarkable physical properties of the copolyesters. The properties of the copolyesters may include increased strain hardening, improved caustic stress crack resistance in carbonated soft drink bottle bases, reduced creep strain, and increased hoop burst stress at bottle failure. Polymerization experiments where DEG suppression measures have been relaxed have confirmed that DEG defect formation in the chain increases with FDCA addition to the polymerization reactor.

[0074] It has been surprisingly demonstrated herein that 1 mol% PETF copolyesters exhibit faster crystallization rates and higher crystallinity development than unmodified PET homopolyester. Copolyester peak melting temperatures over a range of furandicarboxylate compositions spanning from more than 0 to 6 mol% exhibit a linear decrement in peak melting temperature with increasing FDCA addition to the polymer. The data suggests that in low- furandicarboxylate PETF copolyesters where DEG formation is at the same level as or higher than the added FDCA comonomer on a molar basis, furanoate proximal formation of DEG defects improves local chain mobility in the vicinity of the furandicarboxylate co-unit. Enhanced local chain mobility arising from proximal furandicarboxylate-DEG units in the chain would explain the unique crystallization behavior and increased strain hardening behavior observed. PETF copolyesters with FDCA addition exceeding about 2 mol% do not demonstrate similar mechanical properties or deformational characteristics.

[0075] In certain examples, as the FDCA feed to the reactor increases and the reaction proceeds from esterification through polycondensation, DEG formation in the polymer chain has been found to increase commensurately with the FDCA at a rate of about 0.2 mol% DEG per mol% FDCA. Instead of random location of FDCA and DEG in a polymer chain, copolyesters including between about 0.5 mol% and about 2 mol% may include DEG formation highly coordinated with FDCA co-unit incorporation into the polymer chain. Advantageously, the high coordination of DEG formation with FDCA incorporation may facilitate longer crystallizable sequences or runs of terephthalate co-units, which may potentially yield thicker crystalline lamellae and a more pervasive intercrystalline tie-chain network supporting greater strain hardening during deformation. Additionally, or alternatively, free-blown preform testing may indicate differences in stretch dynamics related to increased strain hardening around 1 mol% PETF copolyester relative to either PET control or 2 mol% PETF copolyester.

[0076] Although DEG may inhibit crystallization extent and rate in PET homopolyesters, the present disclosure provides evidence of improved properties for 1 mol% PET copolyester, such as higher Young’s Modulus, bottle burst pressure, and stress crack resistance, relative to either the control PET homopolyester (0 mol% FDCA) or the 2 mol% FDCA PETF copolyester.

[0077] As described herein, the incorporation of naturally-formed DEG in the PETF copolyester may be influenced by the FDCA comonomer. The formation of DEG within the polymer chain may be highly correlated spatially with the insertion of a furandicarboxylate unit. Therefore, while furandicarboxylate insertion within the polycondensing PETF chain may be random, the sequencing of DEG relative to the furandicarboxylate co-unit may not be random, and may be based upon the expressed physical properties of the PETF copolyester in the range of about 0.5 mol% to 2 mol% FDCA. DEG formation may be proximally situated with the furandicarboxylate unit.

[0078] In certain examples, the copolymers of the present disclosure may include from about 0.1 mol% to about 4 mol% of 2,5-furandicarboxylic acid (FDCA or furanoic acid), including, for example, from about 0.2 mol%, or from about 0.3 mol%, or from about 0.4 mol%, or from about 5 mol%, or from about 0.6 mol%, or from about 0.7 mol%, or from about 0.8 mol%, or from about 0.9 mol%, or from about 1.0 mol%, or from about 1.1 mol%, or from about 1.2 mol%, or from about 1.3 mol%, or from about 1.4 mol%, or from about 1.5 mol%, or from about 1.6 mol%, or from about 1.7 mol%, or from about 1.8 mol%, or from about 1.9 mol%, or from about 2.0 mol%, or from about 2.1 mol%, or from about 2.2 mol%, or from about 2.3 mol%, or from about 2.4 mol%, or from about 2.5 mol%, or from about 2.6 mol%, or from about 2.7 mol%, or from about 2.8 mol%, or from about 2.9 mol%, or from about 3.0 mol%, or from about 3.1 mol%, or from about 3.2 mol%, or from about 3.3 mol%, or from about 3.4 mol%, or from about 3.5 mol%, or from about 3.6 mol%, or from about 3.7 mol%, or from about 3.8 mol %, or from about 3.9 mol% to about 4.0 mol%; or from about 0.1 mol% or to about 0.2 mol%, or to about 0.3 mol%, or to about 0.4 mol%, or to about 0.5 mol%, or to about 0.6 mol%, or to about 0.7 mol%, or to about 0.8 mol%, or to about 0.9 mol%, or to about 1.0 mol%, or to about 1.1 mol%, or to about 1.2 mol%, or to about 1.3 mol%, or to about 1.4 mol%, or to about 1.5 mol%, or to about 1.6 mol%, or to about 1.7 mol%, or to about 1.8 mol%, or to about 1.9 mol%, or to about 2.0 mol%, or to about 2.1 mol%, or to about 2.2 mol%, or to about 2.3 mol%, or to about 2.4 mol%, or to about 2.5 mol%, or to about 2.6 mol%, or to about 2.7 mol%, or to about 2.8 mol%, or to about 2.9 mol%, or to about 3.0 mol%, or to about 3.1 mol%, or to about 3.2 mol%, or to about 3.3 mol%, or to about 3.4 mol%, or to about 3.5 mol%, or to about 3.6 mol%, or to about 3.7 mol%, or to about 3.8 mol%, or to about 3.9 mol%; or any range formed from any two of the foregoing mole percentages; including any sub-ranges therebetween. 2,5-Furandicarboxylic acid has the following chemical structure: 2,5-furandicarboxylic acid.

[0079] In certain examples, the copolymers provided herein may include from about 0.1 mol% to about 5.0 mol% of diethylene glycol (DEG) units, including, for example, from about 0.2 mol%, or from about 0.3 mol%, or from about 0.4 mol%, or from about 0.5 mol%, or from about 0.6 mol%, or from about 0.7 mol%, or from about 0.8 mol%, or from about 0.9 mol%, or from about 1.0 mol%, or from about 1.1 mol%, or from about 1.2 mol%, or from about 1.3 mol%, or from about 1.4 mol%, or from about 1.5 mol%, or from about 1.6 mol%, or from about 1.7 mol%, or from about 1.8 mol%, or from about 1.9 mol%, or from about 2.0 mol%, or from about 2.1 mol%, or from about 2.2 mol%, or from about 2.3 mol%, or from about 2.4 mol%, or from about 2.5 mol%, or from about 2.6 mol%, or from about 2.7 mol%, or from about 2.8 mol%, or from about 2.9 mol%, or from about 3.0 mol%, or from about 3.1 mol%, or from about 3.2 mol%, or from about 3.3 mol%, or from about 3.4 mol%, or from about 3.5 mol%, or from about 3.6 mol%, or from about 3.7 mol%, or from about 3.8 mol%, or from about 3.9 mol%, or from about 4.0 mol%, or from about 4.1 mol%, or from about 4.2 mol%, or from about 4.3 mol%, or from about 4.4 mol%, or from about 4.5 mol%, or from about 4.6 mol%, or from about 4.7 mol%, or from about 4.8 mol%, or from about 4.9 mol%, or from about 5.0 mol%; or from about 0.1 mol% to about 0.2 mol%, or to about 0.3 mol%, or to about 0.4 mol%, or to about 0.5 mol%, or to about 0.6 mol%, or to about 0.7 mol%, or to about 0.8 mol%, or to about 0.9 mol%, or to about 1.0 mol%, or to about 1.1 mol%, or to about 1.2 mol%, or to about 1.3 mol%, or to about 1.4 mol%, or to about 1.5 mol%, or to about 1.6 mol%, or to about 1.7 mol%, or to about 1.8 mol%, or to about 1.9 mol%, or to about 2.0 mol%, or to about 2.1 mol%, or to about 2.2 mol%, or to about 2.3 mol%, or to about 2.4 mol%, or to about 2.5 mol%, or to about 2.6 mol%, or to about 2.7 mol%, or to about 2.8 mol%, or to about 2.9 mol%, or to about 3.0 mol%, or to about 3.1 mol%, or to about 3.2 mol%, or to about 3.3 mol%, or to about 3.4 mol%, or to about 3.5 mol%, or to about 3.6 mol%, or to about 3.7 mol%, or to about 3.8 mol%, or to about 3.9 mol%, or to about 4.0 mol%, or to about 4.1 mol%, or to about 4.2 mol%, or to about 4.3 mol%, or to about 4.4 mol%, or to about 4.5 mol%, or to about 4.6 mol%, or to about 4.7 mol%, or to about 4.8 mol%, or to about 4.9 mol%; or any range formed from any two of the foregoing mole percentages; including any sub-ranges therebetween.

[0080] In an example, the present disclosure provides copolyesters having crystallinity from about 3 wt% to about 70 wt%, including from about 5 wt%, or from about 10 wt%, or from about 15 wt%, or from about 20 wt%, or from about 25 wt%, or from about 30 wt%, or from about 35 wt%, or from about 40 wt%, or from about 45 wt%, or from about 50 wt%, or from about 55 wt%, or from about 60 wt%, or from about 65 wt% to about 70 wt%; or from about 3 wt% to about 5 wt%, or to about 10 wt%, or to about 15 wt%, or to about 20 wt%, or to about 25 wt%, or to about 30 wt%, or to about 35 wt%, or to about 40 wt%, or to about 45 wt%, or to about 50 wt%, or to about 55 wt%, or to about 60 wt%, or to about 65 wt%; or any range formed from any two of the foregoing weight percents; including any sub-ranges therebetween. In certain examples, a copolyester has a crystallinity of from about 10 wt% to about 70 wt%. In other examples, a copolyester has a crystallinity of from about 20 wt% to about 65 wt%. In still other examples, a copolyester has a crystallinity of about 30 wt%. In still other examples, a copolyester has a crystallinity of about 65 wt%.

[0081] In certain examples, the present disclosure provides bio-based copolyester systems in which the narrow composition range and monomer structures define the uniqueness of the resulting polymer and its benefits.

[0082] In an example, the copolyesters and copolyester resins described herein may be used in a variety of material applications. For example, a copolyester may be processed by performing preform injection molding. In certain examples, a copolyester may be further processed by performing reheat stretch blow bolding. In other examples, a copolyester may be used in the manufacture of preforms, closures, or medical fluid connection devices. In still other examples, a copolyester may be used in the injection molding of an article, the extrusion of a film or sheet, the thermoforming of a sheet, or the spinning of a fiber.

[0083] In an example, the present disclosure provides a copolyester, including: from about 0.5 mol% to about 2 mol% of 2, 5 -furandicarboxylic acid monomer units; and from about 3 mol% to about 4 mol% of diethylene glycol units; wherein the copolyester is formed by esterification and polycondensation reactions including an aromatic or aliphatic dicarboxylic acid, 2,5- furandicarboxylic acid, and ethylene glycol.

[0084] In certain examples, the copolyester may include from about 0.7 mol% to about 1.5 mol% of 2,5-furandicarboxylic acid monomer units.

[0085] In certain examples, the dicarboxylic acid may be terephthalic acid.

[0086] In certain examples, the copolyester may include from about 0.5 mol% to about 3.8 mol% of diethylene glycol units.

[0087] In certain examples, the copolyester may have an intrinsic viscosity above about 0.6 dL/g at 30°C.

[0088] In certain examples, the copolyester may have an intrinsic viscosity above about 0.7 dL/g at 30°C.

[0089] In certain examples, the copolyester may have an intrinsic viscosity above about 0.8 dL/g at 30°C.

[0090] In certain examples, the copolyester may have a crystallinity of from about 3 wt% to about 70 wt%.

[0091] In certain examples the copolyester may have a crystallinity of at least about 10 wt%. [0092] In certain examples, the copolyester may have a crystallinity of at least about 20 wt%.

[0093] In certain examples, the copolyester may have a crystallinity of at least about 25 wt%.

[0094] In certain examples, the copolyester may have a crystallinity of at least about 35 wt%.

[0095] In certain examples, no ethylene glycol is added to the esterification or polycondensation reactions.

[0096] In certain examples, a preform may include the copolyester.

[0097] In certain examples, a container may include the copolyester or the preform.

[0098] In certain examples, a fiber may include the copolyester.

[0099] In certain examples, a film may include the copolyester.

[0100] In certain examples, a sheet may include the copolyester.

[0101] In certain examples, a molded article may include the copolyester.

[0102] In certain examples, a method of producing the copolyester may include: esterifying the aromatic or aliphatic dicarboxylic acid and ethylene glycol in the presence of the 2,5- furandicarboxylic acid at a suitable esterifying temperature to produce esterification products; and polycondensing the esterification products at a suitable polycondensing temperature to produce the copolyester. [0103] In certain examples, an ethylene glycol molar excess of the esterifying may be 120 - 200% of a total dicarboxylic acid charge of the dicarboxylic acid and the 2,5-furandicarboxylic acid.

[0104] In certain examples, the esterifying may be in the presence of a catalyst, a stabilizer, a bluing agent, and/or a suppressant.

[0105] In certain examples, the catalyst may include antimony trioxide.

[0106] In certain examples, the stabilizer may include phosphoric acid.

[0107] In certain examples, the bluing agent may include cobalt acetate tetrahydrate.

[0108] In certain examples, the suppressant may include tetraalkylammonium hydroxide.

[0109] In certain examples, the suppressant may include tetramethylammonium hydroxide and/or tetraethylammonium hydroxide.

[0110] In certain examples, the suitable esterifying temperature may be from 180°C to 300°C. [0111] In certain examples, the suitable esterifying temperature may be from 180°C to 270°C. [0112] In certain examples, the suitable polycondensing temperature may be from 200°C to 300°C.

[0113] In certain examples, the suitable polycondensing temperature may be from 270°C to 290°C.

[0114] In certain examples, a method of producing the preform may include injection-molding the copolyester to produce the preform.

[0115] In certain examples, a method of producing the container may include reheat stretch blow-molding the preform to produce the container.

EXAMPLES

[0116] The present disclosure may be better understood in connection with the following Examples. In addition, the non-limiting examples are an illustration. The person skilled in the art will appreciate that it may be necessary to vary the procedures for any given example of the present disclosure, for example, vary the order or steps and/or the chemical reagents used.

[0117] Test Methods.

[0118] A. Conventional Differential Scanning Calorimetry (DSC).

[0119] Thermal properties of resins were measured using a TA Instruments DSC 250 Differential Scanning Calorimeter. A 5-10-milligram sample of the resin was placed in a 5.4- millimeter Tzero® aluminum pan for the heat/cool/heat thermal scan experiment. The first heating cycle was performed with the sample in an isothermal hold for 1 minute at 40°C. The sample was heated at 10°C/min to 290°C and held for 1 minute. The cooling cycle was performed at a cooling rate of 10°C/min to 40°C and the sample was equilibrated. The final heating ramp was performed at 10°C/min to 290°C. Endotherm and exotherm peaks were identified and integrated with Trios® software using a linear double-point baseline. The glass transition temperature was measured using TA Instruments Trios® software and was identified as the temperature at half step height. Sample crystalline fraction (mass basis) was calculated using the formula: which corrects the melting enthalpy for the cold crystallization enthalpy A/7 _C c and uses the PET standard melting enthalpy of a perfect crystal A//° _m of 140 J/g (26.9 J/mol).

[0120] B. Non-Isothermal Crystallization from the Melt (Melt Crystallization).

[0121] The test sequence for the DSC conformed to the following procedure for crystallization from the melt: (a) using a rate of 20°C/min in an inert nitrogen atmosphere, heating the loaded sample pan to a temperature 20°C above the peak melting temperature; (b) holding the sample at the temperature for 5 minutes; (c) executing a cooling rate scan within the accessible and controllable range of the DSC instrument and recording the crystallization exotherm as the sample is cooled to room temperature; (d) upon cooling to rom temperature, ending the measurement process for the sample; (e) repeating (a) to (d) for another cooling rate with a fresh sample, performing 5 non-isothermal crystallization scans for each resin sample, with rates equally spaced on a logarithmic scale over the accessible and controllable cooling rate range for the DSC instrument. The 5 cooling rates used were 2.5°C/minute, 5.0°C/minute, 10.0°C/minute, 20.0°C/minute, and 40.0°C/minute.

[0122] C. Non-Isothermal Crystallization from the Glass (Cold Crystallization).

[0123] The test sequence for the DSC conformed to the following procedure for crystallization from the glass: (a) using a rate of 20°C/min in an inert nitrogen atmosphere, heating the loaded sample pan to a temperature 20°C above the peak melting temperature; (b) holding the sample at the temperature for 5 minutes; (c) cooling the sample as quickly as the DSC instrument may control to at least 5°C below the sample’s glass transition temperature, or room temperature, whichever temperature is lower; (d) heating the sample at a heating rate within the control capability of the DSC instrument to a temperature no greater than 10°C below the onset of the final peak melting temperature and recording the crystallization exotherm as the sample is heated; (e) once the sample was cooled to room temperature, ending the measurement process for the sample; (f) repeating (a) through (e) for another heating rate with a fresh sample, performing 5 non-isothermal crystallization scans for each resin sample, with rates equally spaced on a logarithmic scale over the accessible and controllable cooling rate range for the DSC instrument. The 5 heating rates used were 2.5°C/minute, 5.0°C/minute, 10.0°C/minute, 20.0°C/minute, and 40.0°C/minute.

[0124] D. Proton Nuclear Magnetic Resonance ( ^X H NMR).

[0125] 2,5-Furandicarboxylate and diethylene glycol (DEG) moieties within the resins were identified using a Bruker Avance® III 600 MHz NMR spectrometer. ¹ H NMR spectra were obtained using a sample solution prepared by dissolving approximately 30 milligrams of resin in deuterated tetrachloroethane at 50°C. Peak resolution and integration was accomplished using MestreNova software. Chemical shifts for monomer/comonomer residues were 4.8 ppm for ethylene glycol, 8.1 ppm for terephthalic acid, 7.2 ppm for 2,5-furandicarboxylic acid, and 45 ppm for diethylene glycol. Spectrum acquisition time was 6 hours.

[0126] E. CIE L*a*b* Color Space.

[0127] As understood, the CIE L*a*b* color space is a color scale for determining a color. The three coordinates (or dimensions/components) of CIE L*a*b* represent the lightness of the color (L*=0 indicates black and L*=100 indicates white), the position between red (sometimes referenced as magenta) and green (negative a* values indicate green while positive a* values indicate red), and the position between yellow and blue (negative b* values indicate blue and positive b* values indicate yellow). The L* component closely matches human perception of lightness. Using the CIE L*a*b* color space, the difference (for example, a AE*) in color between a standard and observed color may be measured, and the extent to which the desired color of a coating is altered by the components therein may be measured.

[0128] F. Intrinsic Viscosity.

[0129] Intrinsic viscosity is determined by measuring the flow time of a solution of known polymer concentration and the flow time of the pure solvent in a capillary viscometer at a fixed temperature. The intrinsic viscosity is calculated from the flow time values.

[0130] About 0.2500 grams of sample was weighed into a clean, dry 50-mL volumetric flask. A TFE-fluorocarbon plastic-coated stirring bar was placed into the flask and approximately 25 milliliters of solvent was added. Another flask was prepared without any sample present. The flasks were capped. The flasks were placed in steel beakers and placed on a magnetic hot plate that was preheated to 110°C ± 10°C. The flasks were heated for 15 minutes while stirring. The flasks were removed and inspected for undissolved sample. If a sample was not completely dissolved, the stirring time was extended for up to 30 more minutes with inspecting of the sample at 10-minute intervals. When the samples were completely dissolved, the flasks were removed from the hot plate and allowed to cool to approximately room temperature. The stirring bars were removed with a magnetic retriever and the stirring bars were washed with fresh solvent, letting the wash solvent fall back into the volumetric flask. Additional solvent was added to a level about 1 cm below the 50-mL mark. The flasks were placed in a constant temperature bath preset at 30°C ± 0.01°C. The flasks were allowed to sit for 10 minutes to reach the bath temperature. The stoppered flasks were inverted to wash down solvent droplets adhering to the flask walls above the polymer solution, and sufficient solvent was added to raise the liquid level up to the 50-mL mark.

[0131] The solution was poured into a clean, dry, Cannon-Ubbelohde viscometer by passing the solution through a funnel and filter screen into the top of the larger viscometer tube. The viscometer was filled to a level between the level lines on the large reservoir bulb at the bottom of the larger tube. The funnel was removed and the viscometer was placed in the constant temperature bath preset at 30°C ± 0.01°C. Fifteen minutes was allowed for the temperature of the solution in the viscometer to reach equilibrium.

[0132] Using suction from an aspirator, the solution was drawn to the capillary to a level above the top calibration mark. The level was regulated by capping the breather tube with a rubber- gloved finger and applying suction to the top of the capillary tube. The sample solution or solvent was allowed to flow back down the capillary tube by removing the suction from the top of the capillary tube and removing the finger from the top of the breather tube. The first flow is a rinse to wet the capillary bulb and equilibrate the sample solution to the bath temperature. Drawing the solution into the capillary was repeated, and the period for the liquid to fall back from the higher calibration mark to the lower calibration mark above the capillary was timed with an electric timer. The bottom of the meniscus of the liquid surface was used for determining times. The measurement was repeated three more times. The results were averaged unless the range in time exceeded 0.2 seconds, in which case additional measurements were made until four within a range of 0.2 seconds were obtained. The solvent flow time was measured in the same manner as the flow time of the solution samples. The bath temperature was recorded to the nearest 0.01 °C.

[0133] Intrinsic viscosity was determined as follows by the Billmeyer equation: q = 0.25 (r| _r - 1 + 3 In r| _r )/C where r| is the intrinsic viscosity (dL/g) at 30°C and at a polymer concentration of 0.5 g/dL; rp is the relative viscosity (t/to); t is the average solution flow time (seconds); to is the average solvent flow time (seconds); and C is the polymer solution concentration.

EXAMPLE 1

[0134] Herein is described the synthesis of PETF copolyesters incorporating DEG.

[0135] Diethylene glycol (DEG) formation within the polyester chain may occur during the direct esterification and polycondensation stages of poly(ethylene terephthalate) (PET) and similar polyesters and copolyesters. In each case, DEG is formed through the polycondensation reaction enjoining two hydroxy esters with the release of a water molecule. Thus, two bis- hydroxyesters may unite during esterification, two chain hydroxyl end groups may reactor, or any combination of the two reactions may form a DEG unit within the chain. An elevated reaction temperature, high glycol excess, and high reaction acidity (catalytic effect) may exacerbate DEG formation within the copolyester chain. Reactor scales and designs leading to poor mixing and inadequate heat transfer may also increase in-chain formation of DEG.

[0136] For homopolyester PET, depending upon the esterification mode (for example, direct esterification or transesterification) and polycondensation reaction conditions employed, DEG usually forms at a level of from 1 to 4 mol% in the polyester chain.

[0137] Polymerizations of poly(ethylene terephthalate-co-ethylene 2,5-furandicarboxylate) copolyesters ranging in composition from 0 mol% to 15 mol% 2,5-furandicarboxylic acid (FDCA) have demonstrated that copolymerization with FDCA may escalate the formation of in-chain DEG more than the formation typically observed for PET homopolyester. Surprisingly, it was observed that copolyesters including from 0.5 mol% to 2 mol% FDCA (reactor feed) demonstrated improved physical properties, greater strain hardening behavior, and improved deformational characteristics than either PET or PETF copolyesters approaching 2 mol% FDCA.

[0138] Synthetic Procedure.

[0139] A. Initial Study

[0140] PET and PETF syntheses were performed in a 3-liter reactor at the University of Toledo. The FDCA feed was systematically varied at 0, 0.5, 1.0, 2.0, 3.0, 4.0, and 15.0 mol%. Ethylene glycol (“EG”) molar excess was 150% of the total dicarboxylic acid charge of terephthalic acid (“TA”) and FDCA to the reactor: where [EG]o, [TA]o, and [FDCA]o are the initial amounts of moles of ethylene glycol, terephthalic acid, and 2,5-furandicarboxylic acid, respectively, added before the start of the reaction. Antimony trioxide (86263), phosphoric acid (H3PO4), and cobalt acetate tetrahydrate (CO(OAC)2'4H2O) were added as polymerization catalyst, stabilizer, and bluing agent, respectively. Direct esterification was performed at 260°C (255°C for 15 mol% FDCA) for 5 to 6 hours, followed by polycondensation at 280°C and less than 10 torr vacuum for 5 to 6 hours. The finished resin was expelled from the reactor using dry nitrogen and pelletized to yield resin. Table 1 below summarizes the solid-state polymerization conditions for the PET homopolyester and PETF copolyesters produced. Resin intrinsic viscosities (“TVs”) and DEG formation concentrations are reported.

TABLE 1

[0141] A second series of PET and PETF syntheses was conducted in a direct esterification/polycondensation batch reactor. The initial FDCA charge to the reactor was systematically varied at levels of 0.0, 1.0, and 2.0 mol%. Ethylene glycol (EG) molar excess was 120% of the total dicarboxylic acid charge of terephthalic acid (TA) and FDCA to the reactor. Antimony trioxide (86263 [97%], 260 ppm as Sb), phosphoric acid (H3PO4 [85% aqueous solution], 15 ppm as P), and cobalt acetate tetrahydrate (Co(6Ac)2 AH26, 2 ppm as Co) were added as polymerization catalyst, stabilizer, and bluing agent, respectively. Tetramethylammonium hydroxide (“TMAOH”) was added as a DEG suppressant, and 6 ppm of carbon black was added as a reheat agent for preform reheat stretch blow molding. Tetraalkylammonium hydroxides will generally suppress the formation of DEG, including, for example, TMAOH and/or tetraethylammonium hydroxide. Direct esterification proceeded at 260° C for 3 to 4 hours, followed by polycondensation at 280° C, and less than 10 torr vacuum for 5 to 6 hours.

[0142] The three polyester resins were crystallized and solid-state polymerized to raise the IV from about 0.6 dL/g to a bottle-grade level of 0.84 to 0.85 dL/g. DEG levels in the resins were 3.29, 3.64, and 4.05 mol%, respectively, for the 0.0, 1.0, and 2.0 mol% PETF copolyesters.

[0143] Preform Injection Molding and Reheat Stretch Blow Molding.

[0144] Hemispherical endcap preforms (21 g) having a 28 mm PCO 1881 neck finish, which is an industry-representative PET preform design, were injection molded from the PET homopolyester and the 1.0 and 2.0 mol% FDCA copolyesters on an injection molding machine. For all resins, a nozzle temperature of 280°C was used, yielding an injection pressure of 700 bar for all resins. Cycle times were maintained at 32 seconds, with holding and cooling times of 9 seconds and 16 seconds, respectively. Preform weights (21 g) and concentricity values were identical for all resin variants.

[0145] The preforms were reheat stretch blow-molded into a generic 20-ounce petaloid base carbonated soft drink bottle (straight sidewall bottle design, with no contour) on a linear stretch blow-molding machine operating at 1000 bottles/mold/hour under conventional PET bottle processing conditions (stretch rod speed 1 m/s; preblow/high blow pressure 10/40 bar; preform temperature of about 100°C, and a mold temperature of 45°F (7°C)). Bottle section weights for the top, panel, and base were equivalent at 8 g, 8 g, and 5 g, respectively.

[0146] Copolyester Properties.

[0147] FIG. 1 illustrates the relationship between developed copolyester crystallinity, FDCA in the reactor feed, and the average ethylene terephthalate sequence length computed for the level of FDCA added. The data show an apparent distinct transition in crystallinity development in the range of FDCA feeds of from 0.5 to 2.0 mol% FDCA.

[0148] Bottle Properties and Performance.

[0149] Stretch blow-molded bottles were subjected to analytical testing according to standard International Society of Beverage Technologists (“ISBT”) protocols for drop testing, top load, burst, and caustic stress crack resistance. Samples were also cut from the sidewalls of the bottles for tensile testing in the axial (longitudinal) and hoop (circumferential) directions. The axial and hoop directions correspond to the principal stretch directions for the bottles. The results of the tests for each of the three polyester variants (PET homopolyester, 1.0 mol% PETF copolyester, and 2.0 mol% PETF copolyester) are summarized in Table 2 below, and in FIGs. 1 - 3.

TABLE 2

Bottle testing results for generic 20-ounce carbonated soft drink (CSD) beverage bottle produced from the hemispherical endcap preform

[0150] The physical property and performance attributes provided above in Table 2 demonstrate that the 1 mol% PETF copolyester provides a surprising and unexpected enhancement of properties over PET homopolyester and the 2 mol% PETF copolyester. Without wishing to be bound by theory, the different physical property and performance attributes may be due to preferential location of DEG units near or adjacent to FDCA co-units in chains, which may create longer and more crystallizable ET sequences in an example of a copolyester. Consequently, the longer and more crystallizable ET sequences may lead to increased crystallinity and more pervasive crystalline tie chain connectivity within the polymer. The improved chain network characteristics may enhance strain hardening during deformation, which is indicated by the lower volume expansion, longer time to failure, and higher burst pressure for the 1 mol% PETF. Differences in tensile testing results in the axial and hoop directions may also enhance strain hardening.

EXAMPLE 2

[0151] Additional PETF Copolyester Studies.

[0152] PETF copolyesters were produced at the University of Toledo (UoT, Toledo, OH) in a nominal 3-liter reactor using direct esterification and polycondensation with the amounts and reaction conditions listed in Tables 3. A and 3.B.

TABLE 3.A

Direct Esterification Conditions

TABLE 3.B

PET/PETF Polycondensation Conditions

[0153] Small-scale PETF resin batches with 0.0, 0.5, 1.0, 2.0, 3.0, 4.0, and 15.0 mol% FDCA addition produced at UoT were used primarily for resin characterization to assess the impact of furanoate ester incorporation into PETF copolyesters. Cast extruded and oriented films were produced to facilitate resin characterization and the impact of processing. The properties characterized for the produced resins included chain composition (furanoate and DEG) via proton nuclear magnetic resonance ( ^X H NMR), thermal transition analysis via differential scanning calorimetry (“DSC”) (for example, glass transition temperature (T _g ), melting and crystallization peak temperatures, enthalpies of crystallization and melting), tensile strength (Young’s Modulus of oriented films), oxygen permeability (oriented films), CIELAB L*a*b* color (pellets and oriented film), and oxygen permeability of 3 x 3 (nominal) oriented films.

[0154] Amounts of components and reaction conditions used at PolyTech Resources LLC (“PTR,” Darlington, South Carolina) to produce PETF copolyesters are compiled in Table 4.

TABLE 4

Batch polymerization conditions for PET and the PETF copolyesters produced at PTR

[0155] The larger 100 lb _m 0 to 6 mol% PETF batches produced at PTR were used to produce injection-molded preforms at Plastic Technologies, Inc. (“PTI,” Holland, OH). The bottles produced from the preforms were characterized using several standard testing protocols for properties including, for example, axial and hoop direction tensile properties (ASTM D638- 14), carbonation retention (CarboQC Method, Plastic Technologies), and caustic stress crack resistance and failure, carbonation dimensional stability, burst failure, and shelf-life (International Society of Beverage Technologists (“ISBT”) Packaging Technology Committee Voluntary Test Methods for PET Bottles, September 2020). The preform injection molding conditions are provided below in Table 5.

TABLE 5

Preform injection molding conditions for the production of PET and PETF copolyester preforms at PTI

[0156] The bottle reheat stretch blow molding conditions are provided below in Table 6.

TABLE 6

Preform reheat stretch blow molding conditions for PET and PETF generic 20-ounce carbonated soft drink (“CSD”) bottles produced at PTI

[0157] Approximately 200 of the preforms molded at PTI with the PTR bottle-grade PETF resins were sent to Blow Molding Technologies, Inc. for freeblow experiments (free inflation of heated preforms) to ascertain the preform stretching characteristics as a function of FDCA modification. Freeblow conditions are summarized in Table 7. P0 or “Point 0” is the timing of the free blow cycle when the tip of the stretch rod has reached and touched the inside surface of the preform (about 0.050 seconds after stretch rod deployment). Axial and hoop stretching more closely approximates equibiaxial orientation. Stretch rod speed is 1 m/s. P3 corresponds to free blow initiation when the stretch rod has moved 30% of its total travel length (about 0.075 seconds after stretch rod deployment). Some axial stretching occurs before hoop stretching is initiated (sequential deformation).

TABLE 7

PET and PETF copolyester preform freeblow conditions [0158] Results.

[0159] FIG. 4 illustrates the one-to-one correspondence observed between ethylene 2,5- furandicarboxylate content in polyester as measured by NMR, and the mol% of FDCA added to the polycondensation reactor as tabulated from the reagent masses added to the polymerization preparation processes. Based on the one-to-one correspondence between FDCA addition and copolyester 2,5-furandicarboxylate incorporation, either measure may be used interchangeably herein for copolyester physical property assessments as a function of chain 2,5-furandicarboxylate composition.

[0160] A. Diethylene Glycol (“DEG”) Formation in PETF Complexes.

[0161] FIG. 5 illustrates the increase of DEG formation in PETF copolyesters with the increase in 2,5-furandicarboxylate up to 15 mol% FDCA addition to the polymerization reactor. Three reactor scales were used for the polyester and copolyester syntheses in the work: the smallest reactor (2.0 kg) resided at the University of Toledo; the mid-scale reactor (45.4 kg) resided at PolyTech Resources LLC in Darlington, SC; and the largest reactor (1500 kg) resided at Kolon Industries in Daegu, South Korea. In the polymerization batches, DEG formation in the homopolyester PET ranged from 2.52 mol% at the largest reactor scale to 3.29 mol% at the mid-scale. PET produced in the smallest reactor provided about 3.24 mol% DEG formation. From PET, DEG increased roughly linearly with FDCA addition at about 0.27 mol% DEG / mol% FDCA up to 6 mol% FDCA, regardless of reactor scale. The one batch of 15 mol% PETF indicated a slower DEG formation trend with decreasing slope for 6 to 15 mol% PETF copolyesters.

[0162] Without being bound by any particular theory, it is believed that the increase in DEG incorporation with FDCA addition in the production of PETF copolyesters may be due to a reaction mechanism that occurs between ethylene glycol and a terminal 2-hydroxyethyl 2,5- furandicarboxylate via a 5-membered ring intermediate, as illustrated by Scheme 1 below:

Scheme 1.

In other words, 2,5-furandicarboxylate may bias DEG formation into a chain. Alternatively, DEG formation in PETF copolymers may be completely random with respect to FDCA monomer. If DEG formation was completely random, it would be expected that the crystallizable ethylene terephthalate run length in the PETF copolyester would be shorter, leading to slower crystallization rates, thinner crystalline lamellae, and a lower peak melting temperature. By contrast, furandicarboxylate-biased chain formation of DEG would be expected to yield a faster crystallization rate, thicker crystalline lamellae, and a higher peak melting temperature.

[0163] FIG. 6 illustrates the impact of DEG formation on the crystallizable ethylene terephthalate run lengths in PETF copolyesters produced with random and non-random DEG formation in the chain. Longer ET sequences are shown to contribute to slightly thicker lamellae upon crystallization than would be realized in PETF copolyesters with randomly distributed DEG defects.

[0164] B. Differential Scanning Calorimetry (DSC) - Peak Melting Temperature.

[0165] Conventional DSC was used to determine the peak melting temperatures of PETF copolyesters. FIGs. 7 - 11 illustrate how the DSC second heat peak melting temperature varies with different measures of comonomer content in PETF copolyesters produced in different capacity reactors. The measures of comonomer content include FDCA added to the reactor (FIG. 7), furandicarboxylate content (FIG. 8), incorporated DEG (FIG. 9), total comonomer content (TCM = furandicarboxylate (or FDCA) plus DEG, FIG. 10), and terminal furandicarboxylate-adjacent formation of DEG approximated by the function MAX(FDCA, DEG) (FIG. 11) at each FDCA addition level. Where FDCA addition amount has been used as a surrogate for polyester furandicarboxylate content, the data is identified with an asterisk(*) in the legend.

[0166] The function MAX accounts for the effective comonomer content when DEG is formed adjacent to a furandicarboxylate co-unit constituting a single effective comonomer unit. When the in-chain DEG exceeds the furandicarboxylate content in the PETF copolyester, excess DEG reduces the ethylene terephthalate (ET) run length. When the furandicarboxylate content is higher than the DEG content in the PETF copolyester, the furandicarboxylate level reduces the ET run length (PET crystallizable stem length).

[0167] Second heat melting temperature data in FIGs. 7 - 11 demonstrate varying levels of correlation with the various measures of comonomer addition. Of the measures considered, the MAX comonomer content appears to show the least scatter in the decreasing peak melting temperature trend with increasing comonomer content, which indicates that the increase in DEG with FDCA addition to the reactor may be associated with DEG defect formation adjacent to a chain terminal furandicarboxylate as illustrated in Scheme 1.

[0168] C. Non-Isothermal Crystallization Experiments.

[0169] The non-isothermal crystallization kinetics of PET homopolyester (control) and PETF copolyesters including nominal 0.5, 1.0, and 2.0 mol% FDCA additions were measured to assess the impact of chain furandicarboxylate modification and DEG formation. DEG levels in the PET control and 0.5, 1.0, and 2.0 mol% PETF copolyesters were 3.24 mol%, 3.11 mol%, 3.79 mol%, and 3.79 mol% DEG, respectively. Non-isothermal measurements were performed in cold and melt crystallization modes. Non-isothermal crystallization induction times (FIG. 12), crystallization half-time (FIG. 13), and crystallinity data for cold crystallization (in other words, crystallization developed upon heating from the glass, FIG. 14) are illustrated, and indicate that 0.5 mol% and 1.0 mol% PETF copolyesters crystallized to a slightly greater extent than the PET control resin. The 2.0 mol% PETF crystallized to a much lesser extent.

[0170] Non-isothermal crystallization upon cooling from the melt exhibited greater differentiation in performance. Induction times for the PET control resin and the 1.0 mol% PETF copolyester were reduced by a factor of two relative to the other copolyesters, as illustrated in FIG. 15. Crystallization half-times were comparable for all polyesters, as illustrated in FIG. 16. The extent of crystallinity developed for the 1.0 mol% PETF polyester was substantially higher than for the PET control resin, as illustrated in FIG. 17. Developed crystallinity for the 0.5 mol% and 2.0 mol% PETF copolyesters considerably lagged that of the PET control resin. The response of the 0.5 mol% PETF copolyester was surprising, considering the more moderate response falling between the PET control and the 1 mol% PETF for cold crystallization.

[0171] D. Preform Freeblow Experiments.

[0172] Freeblow inflation experiments were performed on injection-molded preforms heated to 95°C, 100°C, and 105°C at 85 bar/s and 550 bar/s inflation pressure ramp rates. The inflation pressure ramp was triggered when the stretch rod contacted the inside bottom (gate) of the preform. The stretch rod speed was held constant at 1.00 m/s. FIG. 18 illustrates the variation in natural draw ratio (NDR) with increasing FDCA addition to the polymerization reactor. The data in FIG. 18 suggests two regimes for freeblow performance corresponding to a transition in strain hardening behavior for PET homopolyester and PETF copolyesters. The transition appears to occur in the vicinity of 2 - 3 mol% FDCA addition in the copolyester. FIG. 19 illustrates the deformation behavior transition more clearly, confirming the transition is closer to 2 mol% FDCA addition.

[0173] The impact of temperature on the NDR of PETF copolyesters is illustrated in FIGs. 19 and 20. In FIG. 20 the plot is magnified to show the trends in freeblow performance between Indorama 1101 (control PET homopolyester) and the nominal 1 mol% PETF copolyester. The data in FIG. 20 illustrates a lower NDR of about 2.2 for the commercial bottle-grade Indorama 1101 polyester at 95°C and 100°C. At 105°C, the NDR for the Indorama 1101 preform jumps to about 2.63. The homopolyester control preform and the nominal 1 mol% PETF exhibit similar temperature dependencies for the movement of the NDR between low and high inflation rates. For the nominal 2 mol% PETF copolyester, the high rate NDR increases rapidly with temperature. However, for 3 mol% and higher PETF copolyesters, up to 6 mol% FDCA addition, the change in the high rate NDR changes minimally relative to the low inflation rate NDR. FIGs. 19 and 20 suggest low PETF copolyesters exhibit a surprisingly complex temperature-deformation characteristic for preform inflation that is dependent upon the incorporated furanodicarboxylate amount and formed DEG co-units included in the PETF copolyester.

[0174] E. PTI Bottle Production Experiments.

[0175] PET control homopolyester and PETF copolyesters produced with varying addition of FDCA from 0 to 6 mol% were injection-molded into 21.5 gram preforms and stretch blow- molded into generic 20-ounce bottles for further testing and evaluation. Example 1 bottles were produced from polyesters produced in the 45.4 kg reactor, and Example 2 bottles were produced from polyesters produced in the 1500 kg reactor and were injection-molded into 21.5 gram preforms and similarly stretch blow-molded into the similar 20-ounce bottles.

[0176] FIGs. 21 and 22 illustrate ISBT caustic stress crack resistance (“CSCR) performance as a function of PETF copolyester FDCA addition level. FIG. 21 demonstrates the superior performance of the 1 mol% PETF copolyester in CSCR testing. Without being bound by theory, it is believed that the increased level of performance may be due to the interplay between the strain hardening and crystallization kinetic behavior sin the low-PETF copolyesters, because chain orientation and mass distribution in the bottle base contribute substantially to CSCR performance. The overall trend to lower CSCR average failure times observed for Example 1 and 2 bottles indicates that the coupled effects of reduced strain hardening and lower crystallinity appear to reduce CSCR performance in low-PETF copolyesters beyond 1 mol% FDCA addition. [0177] FIG. 23 illustrates the variation in the coefficient of variation (“COV”) for the CSCR failure time as a function of the nominal furandicarboxylate content in the PETF copolyesters prepared in a 45.4-kilogram reactor (open circles) and a 1500-kilogram reactor (open triangles). Preforms produced in the 45.4-kilogram reactor demonstrated a decrease in COV for CSCR failure time with increasing amount of FDCA in the PETF copolyester.

[0178] FIG. 24 illustrates the trend for thickness-normalized burst stress for bottles produced with the control PET homopolyester and PETF copolyesters with 1, 2, 3, 4, and 6 mol% FDCA addition. The data roughly followed the same trend as observed for CSCR, with a maximum bust strength at 1 mol% PETF and a generally decreasing burst strength with increasing furandicarboxylate and DEG content.

[0179] An inverse trend is noted for measurements related to the creep properties of the bottle. The bottle expansion recorded at 13 seconds into the burst test, as illustrated in FIG. 25, registers a drop in expansion for a 1 mol% PETF bottle, which is below the expansion observed for the control PET homopolyester or remaining higher-PETF bottles. A similar trend was noted for the ISBT fill point drop of the bottle under carbonation pressure, as illustrated in FIG. 26. In both cases, the relative deformation response among the PET homopolyester and PETF copolyesters is equivalent and consistent.

[0180] The uses of the terms “a” and “an” and “the” and similar referents in the context of describing the present disclosure (especially in the context of the following claims) are to be construed to cover the both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “plurality of’ is defined by the Applicant in the broadest sense, superseding any other implied definitions or limitations hereinbefore or hereinafter unless expressly asserted by Applicant to the contrary, to mean a quantity of more than one. All methods described herein may be performed in any suitable order unless otherwise indicated herein by context.

[0181] As will be understood by one skilled in the art, for any and all purposes, all ranges recited herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof, as well as the individual values making up the range, particularly integer values. It is therefore understood that each unit between two particular units is also disclosed. For example, if “10 to 15” is disclosed, then 11, 12, 13, and 14 are also disclosed, individually, and as part of a range. A recited range (for example, weight percentages or carbon groups) includes each specific value, integer, decimal, or identity within the range. Any listed range may be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, or tenths. As will also be understood by one skilled in the art, all language such as “up to,” “at least,” “greater than,” “less than,” “more than,” “or more,” and the like, include the number recited and such terms refer to ranges that can be subsequently broken down into sub-ranges. In the same manner, all ratios recited herein also include all sub-ratios falling within the broader ratio. Accordingly, specific values recited for radicals, substituents, and ranges are for illustration only; they do not exclude other defined values or other values within defined ranges for radicals and substituents. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0182] One skilled in the art will also readily recognize that where members are grouped together in a common manner, such as in a Markush group, the invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possible subgroups of the main group. Additionally, for all purposes, the invention encompasses not only the main group, but also the main group absent one or more of the group members. The invention therefore envisages the explicit exclusion of any one or more of members of a recited group. Accordingly, provisos may apply to any of the disclosed categories or examples whereby any one or more of the recited elements, species, or examples may be excluded from such categories or examples, for example, for use in an explicit negative limitation.

[0183] As used herein, the term “aromatic” generally refers to a carbocycle or heterocycle having one or more polyunsaturated rings having aromatic character (in other words, having (4n+2) delocalized n (pi) electrons where n is an integer).

[0184] As used herein, the term “aliphatic” generally refers to a non-aromatic organic moiety or compound.

[0185] As used herein, the terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The present description also contemplates other examples “comprising,” “consisting of,” and “consisting essentially of,” the examples or elements presented herein, whether explicitly set forth or not. [0186] In describing elements of the present disclosure, the terms “1 ^st ,” “2 ^nd ,” “first,” “second,” “A,” “B,” “(a),” “(b),” and the like may be used herein. These terms are only used to distinguish one element from another element, but do not limit the corresponding elements irrespective of the nature or order of the corresponding elements. [0187] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meanings as those generally understood by those skilled in the art to which the present disclosure pertains. Such terms as those defined in a generally used dictionary are to be interpreted as having meanings equal to the contextual meanings in the relevant field of art. [0188] As used herein, the term “about,” when used in the context of a numerical value or range set forth means a variation of ±15%, ±14%, ±10%, or ±5%, among others, would satisfy the definition of “about,” unless more narrowly defined in particular instances.

[0189] Although the present disclosure has been described with reference to examples and the accompanying drawings, the present disclosure is not limited thereto, but may be variously modified and altered by those skilled in the art to which the present disclosure pertains without department from the spirit and scope of the present disclosure.

[0190] The subject-matter of the disclosure may also relate, among others, to the following aspects:

[0191] A first aspect relates to a copolyester, comprising: from about 0.5 mol% to about 2 mol% of 2,5-furandicarboxylic acid monomer units; and from about 3 mol% to about 4 mol% of diethylene glycol units; wherein the copolyester is formed by esterification and polycondensation reactions comprising an aromatic or aliphatic dicarboxylic acid, 2,5- furandicarboxylic acid, and ethylene glycol.

[0192] A second aspect relates to the copolyester of aspect 1, comprising from about 0.7 mol% to about 1.5 mol% of 2,5-furandicarboxylic acid monomer units.

[0193] A third aspect relates to the copolyester of any preceding aspect, wherein the dicarboxylic acid is terephthalic acid.

[0194] A fourth aspect relates to the copolyester of any preceding aspect, comprising from about 0.5 mol% to about 3.8 mol% of diethylene glycol units.

[0195] A fifth aspect relates to the copolyester of any preceding aspect, having an intrinsic viscosity above about 0.6 dL/g at 30°C.

[0196] A sixth aspect relates to the copolyester of any preceding aspect, having an intrinsic viscosity above about 0.7 dL/g at 30°C.

[0197] A seventh aspect relates to the copolyester of any preceding aspect, having an intrinsic viscosity above about 0.8 dL/g at 30°C.

[0198] An eighth aspect relates to the copolyester of any preceding aspect, having a crystallinity of from about 3 wt% to about 70 wt%. [0199] A ninth aspect relates to the copolyester of any preceding aspect, having a crystallinity of at least about 10 wt%.

[0200] A tenth aspect relates to the copolyester of any preceding aspect, having a crystallinity of at least about 20 wt%.

[0201] An eleventh aspect relates to the copolyester of any preceding aspect, having a crystallinity of at least about 25 wt%.

[0202] A twelfth aspect relates to the copolyester of any preceding aspect, having a crystallinity of at least about 35 wt%.

[0203] A thirteenth aspect relates to the copolyester of any preceding aspect, wherein no diethylene glycol is added to the esterification or polycondensation reactions.

[0204] A fourteenth aspect relates to a preform comprising the copolyester of any preceding aspect.

[0205] A fifteenth aspect relates to a container comprising the copolyester of aspects 1 to 13 or the preform of aspect 14.

[0206] A sixteenth aspect relates to a fiber comprising the copolyester of aspects 1 to 13.

[0207] A seventeenth aspect relates to a film comprising the copolyester of aspects 1 to 13. [0208] An eighteenth aspect relates to a sheet comprising the copolyester of aspects 1 to 13.

[0209] A nineteenth aspect relates to a molded article comprising the copolyester of aspects 1 to 13.

[0210] A twentieth aspect relates to a method of producing the copolyester of aspects 1 to 13, comprising: esterifying the aromatic or aliphatic dicarboxylic acid and ethylene glycol in the presence of the 2,5-furandicarboxylic acid at a suitable esterifying temperature to produce esterification products; and polycondensing the esterification products at a suitable polycondensing temperature to produce the copolyester.

[0211] A twenty-first aspect relates to the method of aspect 20, wherein an ethylene glycol molar excess is 120 - 200% of a total dicarboxylic acid charge of the dicarboxylic acid and the 2,5-furandicarboxylic acid.

[0212] A twenty-second aspect relates to the method of aspect 20 or 21, wherein the esterifying is in the presence of a catalyst, a stabilizer, a bluing agent, and/or a suppressant.

[0213] A twenty-third aspect relates to the method of aspect 22, wherein the catalyst comprises antimony trioxide.

[0214] A twenty-fourth aspect relates to the method of aspect 22 or 23, wherein the stabilizer comprises phosphoric acid. [0215] A twenty-fifth aspect relates to the method of aspects 22 to 24, wherein the bluing agent comprises cobalt acetate tetrahydrate.

[0216] A twenty-sixth aspect relates to the method of aspects 22 to 25, wherein the suppressant comprises tetraalkylammonium hydroxide.

[0217] A twenty- seventh aspect relates to the method of aspects 22 to 26, wherein the suppressant comprises tetramethylammonium hydroxide and/or tetraethylammonium hydroxide.

[0218] A twenty-eighth aspect relates to the method of aspects 20 to 27, wherein the suitable esterifying temperature is from 180°C to 300°C.

[0219] A twenty-ninth aspect relates to the method of aspects 20 to 28, wherein the suitable esterifying temperature is from 180°C to 270°C.

[0220] A thirtieth aspect relates to the method of aspects 20 to 29, wherein the suitable polycondensing temperature is from 200°C to 300°C.

[0221] A thirty-first aspect relates to the method of aspects 20 to 30, wherein the suitable polycondensing temperature is from 270°C to 290°C.

[0222] A thirty-second aspect relates to a method of producing the preform of aspect 14, comprising: injection-molding the copolyester to produce the preform.

[0223] A thirty-third aspect relates to a method of producing the container of aspect 15, comprising: reheat stretch blow-molding the preform to produce the container.

[0224] In addition to the features mentioned in each of the independent aspects enumerated above, some examples may show, alone or in combination, the optional features mentioned in the dependent aspects and/or as disclosed in the description above and shown in the figures.