Recycled polyethylene terephthalate and method for producing same

Abstract

Methods and systems for producing recycled content polyethylene terephthalate (r-PET) are provided. Integration of chemical recycling facilities with PET manufacturing facilities helps to minimize adverse environmental impacts while reducing energy consumption and providing a valuable end product with up to 100 percent recycled content. Additionally, the methods and systems described herein can provide high IV, crystalline PET based on dimethyl terephthalate that can exhibit desirable properties during molding and other end-use applications.

Description

[Background technology]

[0001]

[0001] Waste materials, especially non-biodegradable waste materials, can have a negative impact on the environment if disposed of in landfills after a single use. Therefore, from an environmental standpoint, it is desirable to recycle as many waste materials as possible. However, there are still low-value waste streams that are nearly impossible or economically infeasible to recycle using conventional recycling techniques. Furthermore, some recycling processes themselves generate waste streams that are not economically viable to recover or recycle, resulting in additional waste streams that must be disposed of or otherwise altered.

[0002]

[0002] In particular, some chemical recycling processes used to break down waste plastics into simpler products involve many inefficient operations that do not allow for effective recycling of various waste plastics. For example, these recycling processes may require high operating costs, especially in terms of energy consumption, which may offset the financial benefits of using waste plastics as a feedstock.

[0003]

[0003] Solvolysis can be used to break down plastics such as polyethylene terephthalate (PET) into its component monomers (e.g., ethylene glycol and dimethyl terephthalate). PET can be formed from these components, but in many cases, most conventional PET facilities are not configured to produce PET based on terephthalic acid (TPA). PET based on dimethyl terephthalate (DMT) offers operational advantages during end-use manufacturing of plastic components, and therefore, it would be desirable to provide a more efficient, cost-effective method of producing DMT-based PET, especially DMT-based PET that contains recycled content. Summary of the Invention [Means for solving the problem]

[0004]

[0004] In one aspect, the technology relates to a method for producing recycled polyethylene terephthalate (r-PET) from mixed plastic waste, comprising: (a) processing the mixed plastic waste in a plastics processing facility to provide a stream predominately composed of polyethylene terephthalate (PET) waste plastic; (b) subjecting the stream predominately composed of PET waste plastic to methanolysis in a methanolysis facility to form recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT); and (c) reacting at least a portion of the r-EG and / or r-DMT in a reaction zone of a PET production facility to form recycled polyethylene terephthalate (r-PET), wherein the plastics processing facility, the methanolysis facility, and the PET production facility are co-located.

[0005] In one aspect, the present technology provides a method for producing recycled polyethylene terephthalate (r-PET), comprising the steps of: (a) depolymerizing waste plastics containing predominantly polyethylene terephthalate (PET) in a methanolysis reactor to form one or more methanolysis streams comprising methanol, recycled ethylene glycol (r-EG) and / or recycled dimethyl terephthalate (r-DMT); and (b) separating at least a portion of at least one of the r-EG, methanol and r-DMT from the one or more methanolysis streams in one or more distillation columns. (c) reacting r-EG and r-DMT in a reaction zone of a PET production facility to form a recycle PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.50 dL / g; (d) withdrawing a predominantly gas phase stream comprising EG, DMT and / or methanol from the reaction zone of the PET production facility; and (e) separating at least a portion of the gas phase stream withdrawn from the at least one PET production facility from a distillation column comprising one or more methanolysis streams.

[0006]

[0006] In one aspect, the present technology relates to a method for producing recycled polyethylene terephthalate (r-PET), comprising: (a) reacting ethylene glycol (EG) and dimethyl terephthalate (DMT) in a reaction zone of a PET production facility, wherein the EG comprises recycled ethylene glycol (r-EG) and / or the DMT comprises recycled dimethyl terephthalate (r-DMT); (b) withdrawing a gaseous stream from the reaction zone of the PET production facility; (c) contacting the gaseous stream with water to remove at least a portion of the EG and / or water azeotrope-forming compounds present in the gaseous stream; and (d) introducing at least a portion of the azeotrope-forming compounds removed from the gaseous stream into a distillation column of a methanolysis facility.

[0007]

[0007] In one aspect, the present technology relates to a method for producing recycled polyethylene terephthalate (r-PET), comprising the steps of: (a) depolymerizing waste plastics containing predominantly polyethylene terephthalate (PET) in a methanolysis reactor of a methanolysis facility to form at least recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT); (b) reacting the r-EG and / or r-DMT in a reaction zone of a PET production facility to form a recycled PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.65 dL / g; (c) pelletizing at least a portion of the r-PET polymer melt to form r-PET particles; and (d) crystallizing at least a portion of the r-PET particles to form crystalline r-PET particles.

[0008]

[0008] In one aspect, the present technology relates to a method for producing recycled polyethylene terephthalate (r-PET), comprising: (a) transesterifying recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT) in a transesterification reaction zone of a PET production facility to form recycled PET oligomers (r-PET oligomers); (b) polycondensing at least a portion of the r-PET oligomers to result in a recycled PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.65 dL / g; (c) pelletizing at least a portion of the r-PET polymer melt via underwater cutting to form recycled PET (r-PET) particles; and (d) crystallizing the r-PET particles to form crystalline r-PET particles.

[0009]

[0009] In one aspect, the present technology relates to a recycled polyethylene terephthalate (r-PET) resin comprising a diester component having at least 50 mole percent of dimethyl terephthalate (DMT) residues based on the total moles of the diester component, and a diol component having at least 50 mole percent of ethylene glycol (EG) residues based on the total moles of the diol component, wherein the r-PET comprises recycled content obtained from waste plastics, and the r-PET comprises 0.1 mole % or less of each of the following components: methyl 4-formylbenzoate, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl phthalate, methyl isopropyl terephthalate, methyl propyl terephthalate, and methyl isobutyl terephthalate residues.

[0010]

[0010] In one aspect, the present technology relates to a recycled polyethylene terephthalate (r-PET) resin comprising a diester component comprising at least 50 mole percent of dimethyl terephthalate (DMT) residues, based on the total moles of the diester component, and a diol component comprising at least 50 mole percent of ethylene glycol (EG) residues, based on the total moles of the diol component, wherein the r-PET comprises recycled content obtained from waste plastics, and the r-PET comprises at least 0.1 mole % of each of the following compounds: diisobutyl phthalate, methyl 4-ethylbenzoate, and methyl 4-vinylbenzoate.

[0011]

[0011] In one aspect, the present technology relates to a recycled polyethylene terephthalate (r-PET) resin comprising a diester component comprising at least 50 mole percent of dimethyl terephthalate (DMT) residues and 0.50 mole percent or less of terephthalic acid residues, based on the total moles of the diester component, and a diol component comprising at least 50 mole percent of ethylene glycol (EG) residues, based on the total moles of the diol component, wherein the r-PET comprises a recycled content obtained from waste plastics and has an inherent viscosity (IV) in the range of 0.65 to 1.10 dL / g, and the r-PET comprises a plurality of spheroidal particles having an intrinsic viscosity (It.V.) at the surface of each pellet that is less than 0.25 dL / g higher than the It.V. at the center of the particle.

[0012]

[0012] In one aspect, the present technology provides a recycled polyethylene terephthalate (r-PET) resin, comprising a diester component containing at least 50 mole percent of dimethyl terephthalate (DMT) residues based on the total moles of the diester component, and a diol component containing at least 50 mole percent of ethylene glycol (EG) residues based on the total moles of the diol component, the r-PET containing recycled plastics obtained from waste plastics and having an inherent viscosity (IV) of 0.65 to 0.85 dL / g, the r-PET containing a plurality of particles, and an intrinsic viscosity (It.V.) of at least a portion of the surface of the particles being at least 50 mole percent of the diol component. is less than 0.25 dL / g higher than the It.V. at the center of the particle, and at least one of the following is true: (i) the r-PET contains 100 ppm or less of cobalt (Co) and bromide (Br); (ii) the r-PET has a methyl end concentration of at least 5% and not more than 30% based on the total end groups; (iii) the r-PET contains 0.1 mol % or less of residues of 4-carboxybenzaldehyde and 9-fluoreneone-2,6-dicarboxylic acid based on the total moles of polyester. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block flow chart illustrating the main steps of an integrated chemical recycling facility, in particular a plastics processing facility, a solvolysis facility, and a polyethylene terephthalate (PET) manufacturing facility. [Diagram 2]

[0014] FIG. 1 is a block flow chart illustrating the main steps of an integrated chemical recycling facility, in particular a methanolysis facility and a PET production facility. [Diagram 3]

[0015] FIG. 1 is a block flow chart illustrating the main steps of an integrated chemical recycle facility, and in particular an embodiment of a co-located methanolysis and PET production facility. [Figure 4]

[0016] FIG. 1 is a block flow chart illustrating the main steps of an integrated chemical recycle facility, in particular an embodiment of a methanolysis facility and a PET production facility sharing a distillation zone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0017] The inventors have discovered a method and system for chemically recycling waste plastics with efficiency and reduced energy consumption by integrating plastic processing with solvolysis (methanolysis) and PET production. This allows for more efficient manufacturing and chemical recycling along with product formation. Furthermore, this results in the production of high inherent viscosity (IV), crystalline PET formed from recycled EG (r-EG) and / or recycled dimethyl terephthalate (r-DMT) formed during solvolysis. This PET exhibits additional desirable properties both during processing and during the end use of PET. The resulting PET can also have up to 100 percent recycled content.

[0015]

[0018] Turning initially to Figure 1, a process and system for use in the chemical recycling of waste plastics, particularly waste plastics that contain polyethylene terephthalate (PET), is provided. The chemical recycling facility shown in Figure 1 generally includes a plastics processing facility or step, a solvolysis facility or step, and a PET manufacturing facility or step.

[0016]

[0019] Chemical recycling facilities are not mechanical recycling facilities. As used herein, the terms "mechanical recycling" and "physical recycling" refer to a recycling process that includes melting waste plastics and forming the molten plastic into a new intermediate product (e.g., pellets or sheets) and / or a new final product (e.g., bottles). Generally, mechanical recycling does not substantially change the chemical structure of the plastic being recycled. The chemical recycling facilities described herein may be configured to receive and process waste streams from mechanical recycling facilities and / or waste streams that cannot normally be processed by mechanical recycling facilities.

[0017]

[0020] In some cases, at least two or all of the plastic processing facility, the solvolysis facility, and the PET manufacturing facility may share a common location. As used herein, the term "shared a common location" refers to the property of at least two objects located on a common physical site and / or within 5 miles (8 km), 2 miles (3.2 km), 1 mile (1.6 km), 0.75 miles (1.2 km), 0.5 miles (0.8 km), or 0.25 miles (0.4 km) of each other, measured as the straight line distance between the two designated points. When two facilities are said to "share a common location," the distance may be measured between the geographic centers of the facilities.

[0018]

[0021] When two or more facilities share the same location, the facilities may be integrated in one or more ways. Examples of integration include, but are not limited to, heat integration, utility integration, wastewater integration, mass flow integration via conduits, office space for plant management, IT department, maintenance department, cafeteria integration, and sharing of common equipment and parts, such as sealants, gaskets, etc. Specific embodiments of integration between plastic processing facilities, solvolysis facilities, and PET manufacturing facilities are discussed in detail herein.

[0019]

[0022] One or more or all of the plastic processing facility, the solvolysis facility, and the PET manufacturing facility may be industrial-scale facilities. For example, in some cases, the plastic processing facility may receive a mixed waste plastic feedstock stream at an average annual feed rate of at least 500 pounds, at least 1,000 pounds, at least 2,000 pounds, at least 5,000 pounds, at least 10,000 pounds, at least 50,000 pounds, or at least 100,000 pounds per hour averaged over a year. In some cases, the solvolysis facility and / or the PET manufacturing facility may produce one or more recycle product streams at an average annual rate of at least 0.045 t (100 pounds), or at least 0.45 t (1,000 pounds), or at least 2.3 t (5,000 pounds), at least 4.5 t (10,000 pounds), at least 23 t (50,000 pounds), or at least 34 t (75,000 pounds) per hour averaged over a year. In cases where multiple r-product streams are produced, these rates may apply to the combined rates of all r-products.

[0020]

[0023] One or more or all of the plastic processing facilities, the solvolysis facilities, and the PET manufacturing facilities can be operated in a continuous manner. For example, each process within each facility and / or between facilities may be operated continuously and may not include batch or semi-batch operations. In some cases, at least a portion of one or more facilities may be operated in a batch or semi-batch manner, but the operations within the facilities may generally be continuous.

[0021]

[0024] In operation, the chemical recycling facility shown in FIG. 1 can process a mixed waste plastic stream in a plastic processing facility to form predominantly PET waste plastic. As used herein, the term "predominantly" means at least 50 weight percent. The predominantly PET waste plastic stream can then be sent to a solvolysis facility, which can be combined with a solvent before being subjected to a solvolysis reaction. Examples of suitable solvents can include, but are not limited to, (i) water (in which case solvolysis may be referred to as "hydrolysis"), (ii) alcohol (in which case solvolysis may be referred to as "alcoholysis"), such as methanol (in which case solvolysis may be referred to as "methanolysis") or ethanol (in which case solvolysis may be referred to as "ethanolysis"), (iii) glycols, such as ethylene glycol or diethylene glycol (in which case solvolysis may be referred to as "glycolysis"), or (iv) ammonia (in which case solvolysis may be referred to as "ammonolysis"). As shown in Figure 1, the products of solvolysis include recycle glycol (r-glycol), recycle terephthalyl (r-terephthalyl), solvent, and one or more co-products. When the solvolysis facility is a methanolysis facility, the r-glycol includes recycle ethylene glycol (r-EG) and the r-terephthalyl includes recycle dimethyl terephthalate (r-DMT).

[0022]

[0025] As shown in FIG. 1, at least a portion of the r-glycol and / or r-terephthalyl can be transported to a reaction zone of a PET manufacturing facility, where the r-glycol and r-terephthalyl can optionally be reacted with one or more comonomers to form recycled PET oligomers (r-PET). The r-PET oligomers can be further reacted in a polymerization (or polycondensation) zone (not shown in FIG. 1) to form recycled PET polymer melt (r-PET polymer melt). The resulting r-PET polymer melt can then be pelletized and crystallized to form recycled PET (r-PET). In some cases, the r-PET can have a total recycled content of at least 5 percent, at least 10 percent, at least 25 percent, at least 50 percent, at least 75 percent, at least 90 percent, or at least 95 percent, and / or 95 percent or less, 90 percent or less, 75 percent or less, or 50 percent or less.

[0023]

[0026] Turning now to Figure 2, an exemplary chemical recycling facility is shown, including a methanolysis facility. As shown in Figure 2, a mixed waste plastic stream can be introduced into a plastic processing facility. As used herein, the terms "mixed plastic waste" and "MPW" refer to a mixture of at least two types of waste plastics, including but not limited to the following plastic types: polyethylene terephthalate (PET), one or more polyolefins (PO), and polyvinyl chloride (PVC). In some cases, the MPW can include at least 20 weight percent, at least 25 weight percent, at least 30 weight percent, at least 35 weight percent, at least 40 weight percent, at least 45 weight percent, at least 50 weight percent, at least 55 weight percent, at least 60 weight percent, at least 65 weight percent, at least 70 weight percent, at least 75 weight percent, at least 80 weight percent, at least 85 weight percent, at least 90 weight percent, or at least 95 weight percent PET, based on the total weight of the stream. Alternatively, or in addition, the MPW comprises 99.9 weight percent or less, 99 weight percent or less, 97 weight percent or less, 92 weight percent or less, 90 weight percent or less, 85 weight percent or less, 80 weight percent or less, 75 weight percent or less, 70 weight percent or less, 65 weight percent or less, 60 weight percent or less, 55 weight percent or less, 50 weight percent or less, 45 weight percent or less, 40 weight percent or less, 35 weight percent or less, 30 weight percent or less, 25 weight percent or less, 20 weight percent or less, 15 weight percent or less, 10 weight percent or less or 5 weight percent or less PET, based on the total weight of the stream.

[0024]

[0027] In addition to PET, the MPW may include non-PET components, such as other plastics (e.g., polyolefins, polyvinyl chloride, etc.), as well as non-plastic components such as glass, metal, dirt, sand, and cardboard. In some cases, the non-PET components may include other plastics in an amount ranging from 2 to 35 weight percent, 5 to 30 weight percent, or 10 to 25 weight percent, based on the total weight of the stream. The amount of non-PET and non-PO plastics may be at least 2 weight percent, at least 5 weight percent, at least 10 weight percent, at least 15 weight percent, at least 20 weight percent, at least 30 weight percent, at least 40 weight percent, at least 50 weight percent, or at least 55 weight percent, and / or 70 weight percent or less, 60 weight percent or less, 50 weight percent or less, 40 weight percent or less, 30 weight percent or less, 20 weight percent or less, 15 weight percent or less, 10 weight percent or less, 7 weight percent or less, or 5 weight percent or less, based on the total weight of the mixed waste plastics.

[0025]

[0028] In plastics processing facilities, mixed waste plastics can be separated and / or classified to provide a stream dominated by PET waste plastics. In some cases, classification can involve increasing the size of the plastic particles (e.g., by densification or agglomeration), while in other cases, classification can involve reducing the size of the particles (e.g., by grinding / granulation, shredding, chopping, or chopping). In some cases, the size of the PET waste plastic removed from the plastic processing facility may be in the form of particles having a D90 particle size of less than 25.4 mm (1 inch), less than 19.1 mm (3 / 4 inch), or less than 12.7 mm (1 / 2 inch), or a D90 particle size range of 1.59 mm (1 / 16 inch) to 25.4 mm (1 inch), 3.18 mm (1 / 8 inch) to 19.1 mm (3 / 4 inch), 6.35 mm (1 / 4 inch) to 15.9 mm (5 / 8 inch), or 9.53 mm (3 / 8 inch) to 12.7 mm (1 / 2 inch).

[0026]

[0029] In some cases, plastic processing facilities can include separating the waste plastics to remove non-PET plastics and / or non-plastic components (e.g., glass, metal, cardboard and paper, as well as dirt and sand). Such separation can be accomplished mechanically and can include the use of fluids such as air. In some cases, separation can include floating and sinking, where different types of plastics are separated by density, usually using water or a pH-controlled liquid (e.g., lye). In some cases, separation can include the use of hydrocyclones.

[0027]

[0030] As a result, predominantly, the PET waste plastic can comprise at least 50 weight percent, at least 55 weight percent, at least 60 weight percent, at least 65 weight percent, at least 70 weight percent, at least 75 weight percent, at least 80 weight percent, at least 85 weight percent, at least 90 weight percent, at least 95 weight percent, at least 97 weight percent, at least 99 weight percent, at least 99.5 weight percent, or at least 99.9 weight percent PET, based on the total weight of plastics in the stream in which the PET waste plastic predominates. This stream may also contain polyvinyl chloride (PVC) in an amount of at least 0.05 weight percent, at least 0.1 weight percent, at least 0.5 weight percent, at least 1 weight percent, at least 2 weight percent, at least 3 weight percent, at least 5 weight percent and / or 10 weight percent or less, 8 weight percent or less, 6 weight percent or less, 5 weight percent or less, 3 weight percent or less, and may contain polyolefin PO in an amount of 45 weight percent or less, 40 weight percent or less, 35 weight percent or less, 30 weight percent or less, 25 weight percent or less, 20 weight percent or less, 15 weight percent or less, 10 weight percent or less, 5 weight percent or less, 2 weight percent or less, 1 weight percent or less, 0.5 weight percent or less, based on the total weight of the predominantly PET waste plastic.

[0028]

[0031] In some cases, at least a portion of the non-PET (or PO) waste plastics can be chemically recycled in the same or a different chemical recycling facility itself. Examples of chemical recycling processes to which the non-PET (or PO) waste plastics can be subjected include, but are not limited to, pyrolysis, molecular reforming, and combinations thereof.

[0029]

[0032] The PET waste plastic can then be introduced into a reaction zone of a methanolysis facility, as shown in Figure 2. In the reaction zone, the waste plastic can be contacted with a solvent (e.g., methanol) and at least partially depolymerized to form its component monomers (e.g., EG and DMT). The temperature of the methanolysis reaction can be at least 50°C, at least 55°C, at least 60°C, at least 65°C, at least 70°C, at least 75°C, at least 80°C, or at least 85°C, and / or no more than 350°C, no more than 345°C, no more than 340°C, no more than 335°C, no more than 330°C, no more than 325°C, no more than 320°C, no more than 315°C, no more than 310°C, no more than 300°C, or no more than 295°C. The methanol used in the methanolysis reaction is not superheated. In some cases, the solvolysis process may be a low pressure solvolysis process, and the pressure in the solvolysis reactor (or reaction zone) may be within 34 kPa (5 psi), within 69 kPa (10 psi), within 103 kPa (15 psi), within 138 kPa (20 psi), within 172 kPa (25 psi), within 207 kPa (30 psi), within 241 kPa (35 psi), within 276 kPa (40 psi), within 310 kPa (40 psi), within 320 kPa (40 psi), within 360 kPa (40 psi), within 380 kPa (40 psi), within 390 kPa (40 psi), within 410 kPa (40 psi), within 420 kPa (40 psi), within 450 kPa (40 psi), within 460 kPa (40 psi), within 480 kPa (40 psi), within 490 kPa (40 psi), within 500 kPa (40 psi), within 510 kPa (40 psi), within 520 kPa (40 psi), within 530 kPa (40 psi), within 540 kPa (40 psi), within 550 kPa (40 psi), within 560 kPa (40 psi), within 570 kPa (40 psi), within 580 kPa (40 psi), within 590 kPa (40 psi), within 600 kPa (40 psi), within 610 kPa (40 psi), within 620 kPa (40 psi), within 630 kPa (40 psi), within 640 kPa (40 psi), within 650 kPa (40 psi), within 660 kPa (40 psi), within 670 kPa ( a (45 psi) or within 345 kPa (50 psi), or it may be within 379 kPa (55 psi), 517 kPa (75 psi), 621 kPa (90 psi), 689 kPa (100 psi), 862 kPa (125 psi), 1034 kPa (150 psi), 1379 kPa (200 psi), or 1724 kPa (250 psi).

[0030]

[0033] In some cases, the average residence time of the reaction medium in the methanolysis reaction zone may be at least 1 minute, at least 2 minutes, at least 5 minutes, at least 10 minutes, or at least 15 minutes, and / or may be 12 hours or less, 11 hours or less, 10 hours or less, 9 hours or less, 8 hours or less, 7 hours or less, 6 hours or less, 5 hours or less, or 4 hours or less. At least 50 percent, at least 55 percent, at least 60 percent, at least 65 percent, at least 70 percent, at least 75 percent, at least 80 percent, at least 85 percent, at least 90 percent, at least 95 percent, or at least 99 percent of the total weight of PET introduced into the methanolysis facility may be decomposed upon exiting the reaction zone. Additionally, any suitable type of reactor may be used, including, but not limited to, a continuous stirred tank reactor (CSTR), a plug flow reactor, and combinations thereof.

[0031]

[0034] The resulting methanolysis reactor streams withdrawn from the reaction zone can be introduced into a product separation zone as shown in FIG. 2. In the product separation zone, one or more distillation columns can be used to separate the solvent (e.g., methanol), recycle ethylene glycol (r-EG), and recycle dimethyl terephthalate (r-DMT) from the methanolysis co-products, including, for example, light organic co-products, heavy organic co-product streams, and bottoms streams from one or more columns (e.g., glycol column bottoms and DMT column bottoms). These co-product streams can be further processed to recover valuable chemicals or may themselves be chemically recycled in the same or a different chemical recycle facility. For further recycling, one or more co-product streams can be subjected to pyrolysis and / or molecular reforming in the same or a different chemical recycle facility.

[0032]

[0035] Referring again to FIG. 2, at least a portion of the r-EG and / or r-DMT (or both r-EG and r-DMT) withdrawn from the methanolysis facility can be introduced into the reaction zone of the PET production facility. Although shown in FIG. 2 as being introduced separately into the PET reaction zone, the r-DMT and / or r-EG can be introduced into the reaction zone as a single stream. This can be done either by combining the streams of r-DMT and r-EG withdrawn from the methanolysis facility into a single stream prior to its introduction into the PET production facility, or by withdrawing a single stream of r-DMT and r-EG from the methanolysis facility (embodiment not shown). The r-DMT and / or r-EG brought from the methanolysis facility to the PET facility can be in the liquid and / or gas phase.

[0033]

[0036] As shown in Figure 2, the r-DMT and / or r-EG from the methanolysis facility can optionally be combined with another stream of DMT and / or another stream of EG, respectively, which may or may not have a recycle portion. In some cases, the DMT and / or EG combined with the r-DMT and / or r-EG can be virgin, while in other cases, it can include some recycle from another location in the same or a different chemical recycle facility. The DMT introduced into the reaction zone can include at least 10 percent, at least 25 percent, at least 50 percent, at least 75 percent, at least 90 percent, at least 95 percent, at least 99 percent, or 100 percent recycle, and / or the EG introduced into the reaction zone can include at least 10 percent, at least 25 percent, at least 50 percent, at least 75 percent, at least 90 percent, at least 95 percent, at least 99 percent, or 100 percent recycle.

[0034]

[0037] The reaction zone of a PET facility can include at least two major sections: a transesterification section and a polymerization (or polycondensation) section (not shown in FIG. 2). In the transesterification section, EG (or r-EG) and DMT (r-DMT) are reacted in the presence of a transesterification catalyst and, optionally, one or more comonomers to form a PET oligomer (r-PET oligomer). As used herein, the term "oligomer" refers to a polymer species that includes a chain length range of about 7 to about 50. As used herein, the term "monomer" refers to a polymer species that includes a chain length of less than about 3, while the term "polymer" refers to a polymer species that includes a chain length of more than about 50.

[0035]

[0038] During the transesterification reaction, the catalyst may be present in the reaction medium in an amount of at least 1 ppm by weight, at least 2 ppm by weight, at least 4 ppm by weight, at least 5 ppm by weight, and / or no more than 300 ppm by weight, no more than 250 ppm by weight, no more than 200 ppm by weight, no more than 150 ppm by weight, or no more than 100 ppm by weight. Examples of suitable transesterification catalysts include, but are not limited to, titanium alkoxides, tin(II) or tin(IV) esters, alkali or alkaline earth metals (e.g., Li and Ca), manganese compounds, zinc compounds, magnesium acetate or magnesium benzoate, and combinations thereof. Phosphorus-containing compounds and some dyes may also be added to the transesterification reaction zone.

[0036]

[0039] In some cases, one or more comonomers may also be added to the reaction zone of a PET facility and reacted with DMT and EG to form a PET copolymer. As used herein, the term "PET copolymer" refers to PET that contains at least 2 mole percent of the residues of at least one diester (or diacid) other than dimethyl terephthalate and / or at least 2 mole percent of at least one diol other than ethylene glycol.

[0037]

[0040] Examples of suitable diester (or diacid) comonomers can include, but are not limited to, terephthalic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, diphenyl-3,4'-dicarboxylic acid, 2,2-dimethyl-1,3-propanediol, dicarboxylic acids, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and 1,4-cyclohexanedicarboxylic acid, alkyl esters thereof, and combinations thereof. Examples of suitable diol comonomers include, but are not limited to, ethylene glycol (EG), diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, neopentyl glycol, 3-methylpentanediol-(2,4), 2-methylpentanediol-(1,4), 2,2,4-trimethylpentanediol-(1,3), 2-ethylhexanediol-(1,3), 2,2-diethylpropanediol-(1,3), These can include hexanediol-(1,3), 1,4-di(hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2,4,4 tetramethylcyclobutanediol, 2,2-bis-(3-hydroxyethoxyphenyl)-propane, 2,2-bis-(4-hydroxypropoxyphenyl)-propane, isosorbide, hydroquinone, BDS-(2,2-(sulfonylbis)4,1-phenyleneoxy))bis(ethanol), and mixtures thereof.

[0038]

[0041] When present, the diester and / or diol comonomers can constitute up to 50 mole percent of the diester or diol component, based on the total residues of that component. For example, when one or more diester modifying comonomers (e.g., DMI) are used, the PET resin can contain at least 5 mole percent, at least 10 mole percent, at least 25 mole percent, at least 30 mole percent, at least 35 mole percent, at least 40 mole percent, or at least 45 mole percent, and / or 50 mole percent or less, 45 mole percent or less, 40 mole percent or less, 35 mole percent or less, 30 mole percent or less, 25 mole percent or less, or 20 mole percent or less of the diester (or diacid) comonomer(s) residues, based on the total moles of diesters in the PET. Alternatively, or in addition, the PET resin can include at least 5 mole percent, at least 10 mole percent, at least 25 mole percent, at least 30 mole percent, at least 35 mole percent, at least 40 mole percent, or at least 45 mole percent, and / or up to 50 mole percent, up to 45 mole percent, up to 40 mole percent, up to 35 mole percent, up to 30 mole percent, up to 25 mole percent, or up to 20 mole percent of one or more diol comonomers (e.g., NPG) based on the total moles of diol in the resin. In some cases, the comonomer can include recycled comonomers (e.g., r-NPG, r-CHDM, r-DEG), while in other cases the comonomer can include non-recycled or virgin comonomers themselves.

[0039]

[0042] In the reaction zone of the PET production facility, the transesterification (transesterification) step or reaction can be carried out at a temperature of at least 175°C, at least 180°C, at least 185°C, at least 190°C, at least 195°C, at least 200°C, at least 205°C, at least 210°C, at least 215°C, at least 220°C, at least 235°C, at least 245 or at least 250°C, and / or at or below 350°C, at or below 345°C, at or below 335°C, at or below 30°C, at or below 325°C, at or below 320°C, at or below 310°C, at or below 300°C, at or below 285°C or at or below 275°C, and at a pressure of -34 to 241 kPa (-5 to 35 psig), 34 to 241 kPa (5 to 35 psig), 69 to 172 kPa (10 to 25 psig) or 83 to 138 kPa (12 to 20 psig). The pressure of the transesterification reaction may be at least 0 kPa (0 psig), at least 34 kPa (5 psig), at least 69 kPa (10 psig), at least 172 kPa (25 psig), at least 345 kPa (50 psig), or at least 517 kPa (75 psig) and / or no more than 689 kPa (100 psig), no more than 517 kPa (75 psig), no more than 345 kPa (50 psig), no more than 172 kPa (25 psig), no more than 138 kPa (20 psig), no more than 69 kPa (10 psig), or no more than 34 kPa (5 psig).

[0040]

[0043] The transesterification section includes between stages 1-5 (e.g., reactors or vessels) where the transesterification reaction between DMT and EG occurs to form PET monomers and oligomers. Any suitable type of reactor can be used to accomplish the transesterification step, including, but not limited to, CSTRs, plug flow reactors, heat exchangers, horizontal reactors, vertical gravity-driven reactors, falling film reactors, as well as reactive distillation columns, and combinations of two or more of the above.

[0041]

[0044] In some cases, the average chain length of the monomers and / or oligomers exiting the transesterification step may be less than about 25, about 1 to about 20, or 5 to 15. Additionally, in some cases, the DMT conversion after the transesterification reaction may be at least 90 percent, at least 92 percent, at least 95 percent, at least 97 percent, or at least 99 percent. As used herein, the term "conversion" is used to describe the liquid phase properties of a stream subjected to a transesterification reaction, where the conversion of an esterified stream indicates the percent of the original ester end groups that have been converted (i.e., transesterified) to other ester groups. Conversion can be quantified as the number of converted end groups (i.e., alcohol end groups) divided by the total number of end groups (i.e., alcohol + DMT end groups) and expressed as a percentage. Although conversion is used herein, it should be understood that average chain length, which describes the average number of monomer units a compound contains, may also be suitable for describing properties. In some cases, the average chain length of the monomers and / or oligomers exiting the transesterification step may be less than about 25, from about 1 to about 20, or from 5 to 15.

[0042]

[0045] The r-PET oligomers after the transesterification reaction are then subjected to further polymerization or polycondensation in the polymerization section of the reaction zone. During polycondensation, the r-PET oligomers react to form r-PET polymer melt. The polymerization (polycondensation) reaction can be carried out in 1-3 vessels or stages. During polymerization, the monomer and oligomer end groups can further react to release EG, residual methanol, water, diethylene glycol (DEG), and other glycols (if present), which can then allow the polymer weight to build up. The steam removed from the polymerization (or polycondensation) section can be distilled to separate the desired components (e.g., EG and methanol), which can then be reused in various parts of the process, as discussed in more detail in Figures 3 and 4.

[0043]

[0046] Typically, polycondensation can be carried out at temperatures ranging from 220°C to 350°C or 240°C to 320°C and at sub-atmospheric pressure (i.e., vacuum pressure). When polycondensation is carried out in a two-stage process, a prepolymerization (or prepolymer) reactor can convert the monomers and oligomers exiting the transesterification stage into an oligomer / polymer mixture having an average chain length ranging from 2 to 40, 5 to 35, or 10 to 30. A finishing reactor can then convert the oligomer / polymer mixture into a final polyester product (e.g., polymer melt) having the desired average chain length and IV. In some cases, the r-PET polymer melt can have a trimer concentration of 1 weight percent or less, 0.5 weight percent or less, or 0.1 weight percent or less based on the total weight of the r-PET polymer melt. Further, the polycondensation reaction can be carried out in the presence of at least one polycondensation catalyst present in an amount of at least 0.1 ppm, at least 10 ppm, at least 25 ppm, at least 50 ppm, at least 100 ppm, or at least 250 ppm and / or no more than 500 ppm, no more than 350 ppm, no more than 250 ppm, no more than 100 ppm, based on the weight of the PET. Examples of polycondensation catalysts can include at least one catalytically active metal compound, such as titanium, aluminum, antimony, germanium, cobalt, alkali metals and alkaline earth metals, magnesium, calcium, and combinations thereof.

[0044]

[0047] Phosphorus stabilizers may be added during or even after polymerization. The phosphorus stabilizer deactivates the catalyst, thereby stabilizing the polymer. Examples of phosphorus stabilizers include phosphate esters (MERPOL A®) or phosphoric acid. Other additives including pigments (e.g., red and / or blue toners), or reheat (IR) strengthening agents, such as black iron oxide, reduced antimony catalysts, carbon black, and titanium nitride, can also be introduced into the process at various times. When present, the reheat (IR) strengthening agent can be present in an amount of at least 0.1, at least 0.5, at least 1, or at least 1.5 weight percent, and / or 5 weight percent or less, 3 weight percent or less, 2 weight percent or less, 1 weight percent or less, or 0.5 weight percent or less, based on the total weight of the r-PET (or r-PET particles).

[0045]

[0048] The polymerization reaction may be carried out in any type of reactor, including but not limited to pipe reactors, tray reactors, plug flow reactors, falling film reactors, and even reactive distillation columns. In some cases, the polymerization step may include two sub-steps (prepolymerization and finishing) carried out in different reaction vessels. In other cases, the entire polymerization reaction may be carried out in a single step.

[0046]

[0049] In some cases, the polymerization rate (polycondensation) can be adjusted to achieve a desired degree of polymerization or inherent viscosity. For example, the mass transfer rate during at least some or all of the polymerization steps can be at least 1, at least 1.25, at least 1.5, at least 1.75, or at least 2 number average degree of polymerization (DP) / min (DP / min).

[0047]

[0050] The r-PET polymer melt exiting the polymerization zone can have an inherent viscosity (IV) of at least 0.50, at least 0.52, at least 0.55, at least 0.57, at least 0.60, at least 0.62, at least 0.65, at least 0.67, at least 0.68, at least 0.69, at least 0.70, at least 0.71, at least 0.72, at least 0.73, at least 0.74, at least 0.75, at least 0.76, at least 0.77, at least 0.78, at least 0.79, or at least 0.80 dL / g. Additionally or alternatively, the r-PET polymer melt withdrawn from the reaction zone of the PET manufacturing facility may have a viscosity of 1.10 dL / g or less, 1.07 dL / g or less, 1.05 dL / g or less, 1.02 dL / g or less, 1.0 dL / g or less, 0.97 dL / g or less, 0.95 dL / g or less, 0.94 dL / g or less, 0.93 dL / g or less, 0.92 dL / g or less, 0.91 dL / g or less, 0.90 dL / g or less, 0.89 dL / g or less, 0.88 dL / g or less, 0.87 dL / g or less, 0.86 The composition may have an inherent viscosity (IV) of 0.85 dL / g or less, 0.84 dL / g or less, 0.83 dL / g or less, 0.82 dL / g or less, 0.81 dL / g or less, 0.80 dL / g or less, 0.79 dL / g or less, or 0.78 dL / g or less, or it may be in the range of 0.50-1.10 dL / g, 0.60-0.95 dL / g, 0.65-0.90 dL / g, or 0.73-0.85 dL / g, or 0.75-0.83 dL / g. Unless otherwise specified, the inherent viscosity (IV) is measured in 60 / 40 wt / wt phenol / tetrachloroethane at 25°C.

[0048]

[0051] Referring again to FIG. 2, the r-PET polymer melt removed from the reaction zone can be pelletized and then crystallized to form recycle PET (r-PET) particles. As shown in FIG. 2, once the polyester polymer has completed melt phase polymerization, it can form particles that are solid at 25° C. and 1 atm. The r-PET particles can be any suitable shape, including but not limited to spheres, cubes, pellets, chips, tablets, stars, and combinations thereof. In some cases, the particles have a number average weight of at least 0.10, at least 1.0, or at least 50 g per 100 particles. The volume of the particles is not particularly limited, but a bulk of the particles can be provided having a volume of at least 1, at least 3, or at least 5 cubic meters.

[0049]

[0052] The method of pelletizing the r-PET polymer melt is not limited. For example, in some cases, the molten PET may be passed through a die and cut, or passed through a die and then cut to form r-PET particles. A gear pump or a single or twin screw extruder may be used to provide the motive force for the melt to pass through the die, and once through the die, the polyester melt may be cut at the die head. In some cases, the die head may be in a liquid (e.g., water or other aqueous liquid) so that the particles are immediately in contact with the liquid once extruded through the die and cut. This method is generally referred to as underwater cutting. In some cases, the r-PET particles are formed by subjecting the r-PET polymer melt to underwater cutting.

[0050]

[0053] After cutting, the r-PET particles can be optionally at least partially dried and then crystallized to form crystalline r-PET particles. Any suitable method of crystallization can be used, and the particles can be thermally crystallized, for example, in gas or liquid. The crystallization vessel can be a mechanically agitated fluidized bed, a bed agitated by fluid motion, a non-agitated vessel or pipe, or can be contacted with a crystallization liquid medium at a temperature above the glass transition temperature (Tg) of the polyester. In some cases, the crystallization can be latent heat crystallization and can be accomplished without the addition of external heat or energy. Otherwise, the heat of crystallization comes from the particles themselves.

[0051]

[0054] In some cases, the polymer may be fed to the crystallizer at a polymer temperature below its Tg, or may be fed to the crystallizer at a polymer temperature above its Tg. For example, the molten polymer from the melt phase polymerization reactor may be fed through a die plate and cut underwater, and then immediately fed to an underwater thermal crystallization reactor, where the polymer may be crystallized in water. Alternatively, the molten polymer may be cut, cooled below its Tg, and then fed to an underwater thermal crystallization reactor. Alternatively, the molten polymer may be cut in any conventional manner, cooled below Tg, optionally stored, and then crystallized. Optionally, the crystallized polyester spheroids may be in a solid state according to known methods.

[0052]

[0055] As used herein, "solid state polymerization" refers to a process in which polymer chain length increases upon heating of polyester in the substantial absence of oxygen and water. During solid state polymerization, the polymer is in solid form but not in a molten phase. In some cases, the crystallized polyester spheroids are not in a solid state such that less than 10 percent, less than 5 percent, less than 2 percent, less than 1 percent, or less than 0.5 percent of the total inherent viscosity (IV) can be added to the final r-PET after polycondensation. Thus, the difference in inherent viscosity (IV) between the r-PET polymer melt and the crystallized r-PET particles may be 0.25 dL / g or less, 0.20 dL / g or less, 0.15 dL / g or less, 0.10 dL / g or less, or 0.05 dL / g or less.

[0053]

[0056] In some cases, crystalline r-PET can show at least two melting peaks in the first heating scan of a DSC. As used herein, "melting point" refers to the endothermic peak temperature in a differential scanning calorimeter (DSC) at a temperature increase rate of 20°C / min for a sample weighing about 10 mg. It is not necessary to perform a DSC analysis on the particles, but only that the particles have a specified morphology. The specified test reveals the nature of the polymer, but it is only necessary to perform it to determine whether the polymer has the specified property.

[0054]

[0057] When the r-PET particles exhibit at least two melting peaks, the low peak melting point is considered to be Tm1a as further described below, which is classified as a melting peak when the area under the heating curve of the first heating scan of DSC is at least 1 J / g in absolute value. When two or more peaks appear in the heating curve from the first heating scan of DSC, the first peak is the low peak melting point Tm1a, and the second peak is the high peak melting point Tm1b such that Tm1a < Tm1b. The low peak melting point of the polymer particles is in the range of 130°C to 220°C. Preferably, the low peak melting point of the polyester polymer has a peak temperature of at least 140°C, or at least 150°C, or at least 160°C, or at least 170°C and does not exceed 210°C or 200°C or 195°C.

[0055]

[0058] After crystallization, the r-PET particles can be contacted with a vapor stream to strip acetaldehyde (AA) and other undesirable components. This stripping step can be carried out at a gas temperature of at least 25°C, at least 30°C, at least 35°C or at least 40°C, and / or 60°C or less, 55°C or less, 50°C or less or 45°C or less, and at an air pressure of within 34 kPa (5 psig), within 14 kPa (2 psig) or within 7 kPa (1 psig). The average residence time of the r-PET particles in the stripping zone is 1 to 24 hours depending on the temperature of the gas and the mass ratio of the gas to the particles. The residual AA content of the stripped r-PET particles may be AA of 20 ppm or less, 15 ppm or less, 10 ppm or less, 5 ppm or less, 2 ppm or less, 1 ppm or less, or 0.5 ppm or less. Suitable gases can include inert gases such as air, carbon dioxide or nitrogen, which may or may not be dry. The gas can pass through the particles in co-current or counter-current, and the step can be carried out continuously or batchwise in a vessel.

[0056]

[0059] In some cases, the r-PET particles may be spheroidal in shape. As used herein, a "spheroid" is a particle that is substantially but incompletely spherical, nearly spherical, or spherical in shape. It is distinct from slabs, cylinders, tablets, cones, rods, or irregularly shaped particles with corners. Spheroids have a combination of properties. For example, spheroids do not stand on either end of the long axis through their center, and preferably, but not necessarily, they have a y / x ratio of less than 2, where y is the long axis and x is the short axis. Also, if 10.0 g of particles are placed near one edge of a smooth, horizontal steel plate, with the thickness of a pellet of the mass, and the plate is smoothly and gradually lifted by the edge and tilted, the spheroid will roll off the plate, so that when the plate initially forms an angle of 13 degrees with the horizontal, less than 0.5 g of particles will remain on the plate. Spheroids may be spherical, elliptical, ovoid, or tailed.

[0057]

[0060] The spheroid may have a peak mode of the circularity distribution less than 1.4, or less than 1.3, or less than 1.2. The circularity of the spheroid is determined by the perimeter 2 / (4π × area). "Perimeter" and "area" are defined in the context of a cross-section of a spheroid.

[0058]

[0061] In some cases, the crystalline r-PET particles can include spheroids having the melting characteristics described below. For example, in some cases, the r-PET can have a melting point characterized by (a) at least two melting peaks, one of which has a peak temperature in the range of 140° C. to 220° C. as measured in a first heating scan of a DSC, and a lower peak melting point having a melting endotherm area of ​​at least 1 J / g absolute value, or (b) one or more melting points having a heating curve that deviates from the baseline in the endothermic direction at a temperature less than or equal to 200° C. as measured in a first heating scan of a DSC. Alternatively, or in addition, the r-PET particles can have a low degree of crystallinity in the range of at least 20%, and a crystallinity of at least 100% of the formula: Tcmax=50%-DE-OH where DE is the total mole % of all diester residues other than dimethyl terephthalate residues based on 100 mole % of diester residues in PET, and OH is the total mole % of hydroxyl functional compound residues other than ethylene glycol residues based on 100 mole % of hydroxyl functional compound residues. The crystallinity of the crystallinity matrix can be as follows:

[0059]

[0062] In some cases, the r-PET particles can crystallize to a degree of crystallinity of at least 15, at least 20, at least 25, at least 30, at least 35, or at least 40 percent. The crystallinity of the pellets is determined using differential scanning calorimetry (DSC). The sample weight for this measurement is 10±1 mg, and the sample consists of either (1) a portion of a single pellet or, more preferably, (2) a sample taken from several grams of cryo-ground particles. A first heating scan is performed. The sample is heated at a rate of 20° C. / min from approximately 25° C. to 290° C., and the absolute value of the area(s) of the melting endotherm, minus the area of ​​any crystallization exotherms, is determined. This area corresponds to the net heat of fusion, expressed in Joules. The heat of fusion of 100% crystalline PET is taken to be 119 Joules / gram, therefore, the weight fraction crystallinity of the pellets is calculated as the net heat of fusion divided by 119. Unless otherwise stated, the initial melting point for each case is also determined using the same DSC scan. The percent crystallinity is calculated from both the lower peak melting point (Tma1) and the upper peak melting point (Tmb1).

[0060]

[0063] As discussed above, the r-PET particles formed as described herein may not be solid-state polymerized. If not in a solid state, the r-PET particles may have a smaller molecular weight gradient between the surface and center of the particle than can be found in polyester particles in the solid state. In some cases, the polyester polymer particles have a surface and a center, and the intrinsic viscosity (It.V.) at the surface of the particle may be less than 0.25 dL / g, less than 0.20 dL / g, less than 0.15 dL / g, less than 0.10 dL / g, or less than 0.05 dL / g higher than the It.V at the center of the particle.

[0061]

[0064] As used herein, the "surface of the pellet" is defined as the outer 8-12% by weight, while the "center" is defined as the inner 8-16% by weight around the particle center point. The center point of an irregularly shaped particle can be difficult to determine precisely, but it is the best approximation of the intersection between the most straight lines that can be drawn through the particle between the edges or corners that have the longest distance from each other. To measure the It.V. of the surface and center, a random sampling of 10 particles from the batch is gradually dissolved according to the procedure described in the Examples, and the weighted average of all measured intercepts within the first 8-12% by weight dissolved, which is the surface of the pellet, is recorded as the It.V. surface, and the weighted average of all measured intercepts within the last 8-16% by weight, which is the center, is recorded as the It.V. center, and the slope is the difference between the It.V. surface and the It.V. center. There is no limit to the number of measurements made within each range, but there may be as few as one measurement. The GPC method described herein is used to measure the It.V. of each dissolved portion separately. In this way, the gradient starting from the surface of the particle through to the center of the particle may be measured by taking only surface and center sections, or by taking as many sections as desired throughout the particle. Alternatively, the particle may be sliced ​​using a microtome, one piece cut at the surface and one piece cut at the center, which are then measured separately by the GPC method described herein.

[0062]

[0065] The intrinsic viscosity (It.V.) values ​​reported herein are calculated from the inherent viscosity (IV) measured in phenol / tetrachloroethane 60 / 40 wt / wt at 25° C. The inherent viscosity is calculated from the measured solution viscosity. The following formula describes such solution viscosity measurements and the subsequent calculation to IV and from IV to It.V.: η inh =[ln(t s / t o )] / C [In the formula, η inh = Inherent viscosity at 25°C for a polymer concentration of 0.50 g / 100 mL with 60% phenol and 40% 1,1,2,2-tetrachloroethane ln = natural logarithm t s = time it takes for the sample to flow through the capillary t o = time for the solvent to flow through the capillary (blank) C = concentration of polymer (grams) per 100 mL of solvent (0.50%)].

[0063]

[0066] Intrinsic viscosity is the limiting value at infinite dilution of the specific viscosity of a polymer. It is defined by the following formula: η int =lim(η sp / C)=lim ln(η r / C) C → 0 C → 0 [In the formula, η int = intrinsic viscosity η r = relative viscosity = t s / t o η sp =Specific viscosity=η r -1].

[0064]

[0067] Instrument calibration involves repeated testing of standard samples and then applying a suitable mathematical formula to produce an "accepted" IV value. Calibration factor = Accepted IV of reference material / average of repeated measurements Corrected IV = Calculated IV x Calibration Factor

[0068] Intrinsic Viscosity (It.V. or η int ) may be evaluated using the Billmeyer formula as follows: η int =0.5[e 0.5×補正IV -1] + (0.75 x correction IV)

[0069] Recycle PET formed as described herein can include a diester component that includes at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 mole percent of dimethyl terephthalate (DMT) residues, based on the total moles of the diester component; and a diol component that includes at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, or at least 99 mole percent of ethylene glycol (EG) residues, based on the total moles of the diol component.

[0065]

[0070] All compounds containing ester groups (or corresponding acid groups) present in r-PET include the "diester components" and the mole percent of all compounds containing ester groups in r-PET add up to 100. The residue of a compound(s) containing an ester group in r-PET refers to the portion of the compound(s) that remains in the oligomeric and / or polymeric chain after a condensation reaction with a compound(s) that contains a hydroxyl group(s). The residue of a diester component refers to the portion of a component that remains in the oligomeric and / or polymeric chain after the component condenses with a compound that contains a hydroxyl group(s).

[0066]

[0071] All compounds containing hydroxyl group(s) or derivatives thereof that become part of r-PET include the "diol component" and the mole percentages of all compounds containing hydroxyl groups in r-PET add up to 100. The residue of the compound(s) containing hydroxyl group(s) that become part of r-PET refers to the portion of the compound(s) remaining in r-PET after the compound(s) condense with compound(s) containing diester group(s) or further polycondense with polymer chains of varying length. The residue of the diol component refers to the portion of the component that remains in r-PET. The mole percentages of hydroxyl and diester residues in r-PET can be determined by proton NMR.

[0067]

[0072] In some cases, r-PET can contain 0.1 mole percent or less, 0.05 mole percent or less, or 0.01 mole percent or less of residues of one or more (or each) of the following components: methyl 4-formylbenzoate, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl phthalate, methyl isopropyl terephthalate, methyl propyl terephthalate, and methyl isobutyl terephthalate. Such components can be found in virgin DMT and may be absent or substantially absent in the r-DMT used to produce the r-PET described herein. In some cases, r-PET can contain 0.5 mole percent or less, 0.1 mole percent or less, or 0.05 mole percent or less of methyl ethyl terephthalate residues, based on the total moles of diester components.

[0068]

[0073] Alternatively, or in addition, r-PET may contain at least 0.1, at least 0.5, at least 0.75, or at least 1 mole percent and / or no more than 2 mole percent, no more than 1.5 mole percent, or no more than 1 mole percent of one or more (or each) of the following components: diisobutyl phthalate, methyl 4-ethylbenzoate, and methyl 4-vinylbenzoate. Such components are not found in virgin DMT, but may be present in r-DMT used to form r-PET as described herein. Other components that may be present in such amounts include, for example, methyl 4-acetylbenzoate, methyl cyanobenzoate, nonylphenol, methyl stearate, methyl laurate, methyl 4-bromobenzoate, diethylene glycol methyl ether, methyl caprylate, 4-methylenecyclohexylmethanol, and dimethyl 9-oxo-9H-fluorene-2,6-dicarboxylate.

[0069]

[0074] In some cases, the r-PET may be a DMT-based PET and may contain little or no residues of terephthalic acid (TPA). For example, the crystalline r-PET (or r-PET particles) may contain 0.50 mole percent or less, 0.25 mole percent or less, 0.10 mole percent or less, or 0.05 mole percent or less of terephthalic acid residues, based on the total moles of the diester component. In some cases, the lack of TPA in the system may result in lower in situ formation of diethylene glycol (DEG), and the r-PET (or r-PET particles) may have a DEG content of 1.75 mole percent or less, 1.5 mole percent or less, 1.25 mole percent or less, 1 mole percent or less, 0.75 mole percent or less, or 0.5 mole percent or less, 0.45 mole percent or less, or 0.40 mole percent or less, based on the total moles of the diol component. Additionally, or alternatively, the amount of DEG present in the crystalline r-PET (or r-PET particles) described herein may be at least 0.1, at least 0.2, at least 0.25, at least 0.30, or at least 0.35 mole percent, based on the total moles of diol components.

[0070]

[0075] In some cases, r-PET may contain little or no isophthalic acid residues, which may originate from the addition of isophthalic acid (IPA) and / or dimethyl isophthalate (DMI) to the reaction zone. For example, crystalline r-PET (or r-PET particles) may contain 0.50 mole percent or less, 0.25 mole percent or less, 0.10 mole percent or less, or 0.05 mole percent or less of isophthalate residues, based on the total moles of diester components. In other cases, isophthalate residues may be used as an acid comonomer and may fall within one or more of the ranges discussed herein.

[0071]

[0076] In some cases, r-PET may also be free of other components normally associated with TPA-based PET. For example, in some cases, r-PET may contain 100 ppm or less, 75 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less of cobalt (Co) and / or bromide (Br) normally present in the process of forming TPA. Additionally or alternatively, r-PET may contain 100 ppm or less, 75 ppm or less, 50 ppm or less, 25 ppm or less, or 10 ppm or less of one or more metals selected from manganese (Mn), zinc (Zn), and combinations thereof. In some cases, PET may contain 0.1 mole percent or less, 0.05 mole percent or less, or 0.01 mole percent or less of residues of 4-carboxybenzaldehyde and 9-fluorenone-2,6-dicarboxylic acid, based on the total moles of PET. These components are typical intermediates in the TPA-based PET process and are absent (or present in very small amounts) in DMT-based PET.

[0072]

[0077] Additionally, in some cases, r-PET formed from r-DMT described herein may contain at least 5, at least 7, at least 10, at least 12, at least 15, or at least 20 percent, and / or no more than 30 percent, no more than 27 percent, no more than 25 percent, no more than 17 percent, or no more than 15 percent methyl end groups relative to the total number of end groups. PET containing TPA-based terephthalyl residues typically does not have methyl end groups within these ranges. In some cases, r-PET can have a carboxyl value of less than 15 meq / kg, less than 10 meq / kg, less than 7 meq / kg, less than 5 meq / kg, or less than 2 meq / kg.

[0073]

[0078] r-PET is less than 2, less than 1, or less than 0, or in the range of -2 to 2, -1.5 to 1.5, or -1 to 0. *Additionally or alternatively, the r-PET may have an L of greater than 70, greater than 75, greater than 80, or greater than 85, and / or less than or equal to 95, less than or equal to 92, less than or equal to 90, or less than or equal to 87. * It can have a color.

[0074]

[0079] As discussed herein, r-PET can include one or more comonomers that modify the diester and / or diol components of the resin. The modifying monomer(s) can include a modifying diol, a modifying diester (or acid), or both a modifying diol and a diester (or acid). Examples of modifying monomers include, but are not limited to, 1,4-cyclohexanedimethanol (CHDM), neopentyl glycol (NPG), isophthalic acid (IPA), dimethyl isophthalate (DMI), and diethylene glycol (DEG). One or more of the modifying monomers can include recycled content. In some cases, the r-PET contains at least 1, at least 5, at least 10, at least 15, at least 20, at least 25, at least 30, at least 35, or at least 40 mole percent and / or 50 mole percent or less, 45 mole percent or less, 40 mole percent or less, 35 mole percent or less, 30 mole percent or less, 25 mole percent or less, 20 mole percent or less, 15 mole percent or less, 10 mole percent or less, or 5 mole percent or less of at least one modifying monomer, based on the total moles of the diester component, the diol component, or both.

[0075]

[0080] r-PET may be used in a variety of end-use applications including sheets, films, trays, rods, tubes, lids, bottles (water bottles, hot fill bottles, and carbonated soft drink bottles), as well as packaging and filaments and fibers. Additionally, r-PET may be used to form injection molded articles.

[0076]

[0081] As discussed herein, in some cases, the methanolysis facility and the PET production facility may share the same location. When shared, one or more streams from one facility may be transported and utilized in the other, thereby consolidating the facilities. Such consolidation can reduce energy consumption and increase overall process efficiency, allowing for the production of up to 100 percent recycled PET.

[0077]

[0082] Turning now to FIG. 3, a portion of a chemical recycling facility is shown that includes co-located methanolysis and PET manufacturing facilities. In some cases, the chemical recycling facility may further include co-located and integrated plastic processing facilities, as shown in FIG. 1 and FIG. 2. When integrated, the facilities may share utilities, such as furnaces, steam, condensate, heat transfer media (HTM), cooling towers, water, cooling water, nitrogen, tap water, wastewater treatment, flare systems, and catalyst systems. Additionally, they may share facilities such as office facilities, warehouse facilities, and the like. Plastic processing and its associated components and streams may also be co-located and integrated with the methanolysis and / or PET facilities.

[0078]

[0083] Referring again to Figure 3, the r-DMT and / or r-EG from the methanolysis facility can be introduced into the transesterification zone of the PET production facility, optionally along with DMT (or r-DMT) and / or EG (or r-EG) from another source (not shown). When the methanolysis and PET production facilities share the same location and are in fluid communication with one another, the r-DMT and / or r-EG can be transported between the two facilities with little or no cooling or separation. For example, the temperature of the r-DMT can be maintained above a minimum temperature of at least 125, at least 130, at least 135, at least 140, at least 145, or at least 150°C as it is transported from the methanolysis facility to the PET production facility (e.g., from the outlet of the r-DMT vessel in the methanolysis facility to the inlet of the vessel in the PET production facility). Additionally, at least 85, at least 90, at least 95, at least 97, at least 99, or 100 percent of the r-DMT removed from the methanolysis facility can be introduced into the PET facility. Similarly, the temperature of the r-EG can be maintained above a minimum temperature of at least 125, at least 130, at least 135, at least 140, at least 145, or at least 150° C. as it is transported from the methanolysis facility to the PET production facility. Additionally, at least 85, at least 90, at least 95, at least 97, at least 99, or 100 percent of the r-EG removed from the methanolysis facility can be introduced into the PET facility.

[0079]

[0084] In some cases, the total migration path (or transport path) of r-EG and / or r-DMT (e.g., from the outlet of the methanolysis facility to the inlet of the PET facility) may be less than 8.0 km (5 miles), less than 4.8 km (3 miles), less than 3.2 km (2 miles), less than 1.6 km (1 mile), or less than 457 m (1500 feet), less than 305 m (1000 feet), or less than 152 m (500 feet), measured from the outlet of the methanolysis facility to the inlet of the PET facility. Alternatively, the total path of travel may be at least 30 m (100 ft), at least 152 m (500 ft), at least 0.8 km (0.5 mile), at least 1.6 km (1 mile) or at least 3.2 km (2 miles) and / or no more than 8.0 km (5 miles), no more than 6.4 km (4 miles), no more than 4.8 km (3 miles), no more than 3.2 km (2 miles), no more than 2.4 km (1.5 miles) or no more than 1.6 km (1 mile).

[0080]

[0085] Further, there may be little or no intermediate storage of r-DMT and / or r-EG between the two facilities, for example, the value of intermediate storage (e.g., tank storage) of r-DMT and / or r-EG between the two facilities may be 5 days or less, 4 days or less, 3 days or less, 2 days or less, or 1 day or less.

[0081]

[0086] In other cases, the PET and methanolysis facilities may be located remotely from one another, but still be integrated. For example, vapors from the methanolysis facility may be cooled and condensed, and the condensed vapors may be transported to the methanolysis facility. In such cases, temporary storage between the two facilities may suffice for more than 5 days, at least 10 days, at least 15 days, at least 20 days, or more, and the methanolysis facility may share the same location as the PET production facility, or may be located remotely from both.

[0082]

[0087] Referring again to Figure 3, during the transesterification reaction carried out in the reaction zone of the PET production facility between DMT and EG, methanol is released as a by-product and may be collected in the vapor phase from the transesterification step and introduced into the distillation zone. Additionally, additional methanol and vaporized EG (as well as other vaporized by-products and comonomers) from the polymerization zone may also be collected and sent to the distillation zone. In some cases, the one or more streams withdrawn from the reaction zone and introduced into the distillation zone may contain at least 0.5 weight percent, at least 1 weight percent, at least 2 weight percent, or at least 5 weight percent, and / or 10 weight percent or less, 7 weight percent or less, 5 weight percent or less, 2 weight percent or less, or 1 weight percent or less of terephthalyl components based on the total weight of the streams.

[0083]

[0088] In the distillation step or zone, one or more distillation columns may be used to separate DMT (r-DMT) or terephthalyl components (r-terephthalyl components), EG (r-EG), methanol (r-methanol), and other components such as water, low boilers (e.g., components having a boiling point lower than methanol and / or EG), and high boilers (e.g., components having a boiling point higher than EG). As shown in FIG. 3, at least a portion of the r-methanol recovered from the distillation zone of the PET manufacturing facility can be introduced into the reaction zone of the methanolysis facility. In some cases, at least 50, at least 60, at least 70, at least 80, at least 90, at least 95, or at least 99 percent of the methanol recovered from the PET manufacturing facility can be used in the methanolysis facility reaction zone. Furthermore, as shown in FIG. 3, all or a portion of the methanol recovered in the product separation zone of the methanolysis facility can also be returned to the reaction zone for further use. 1, EG (r-EG) recovered in the distillation zone of the PET plant may be returned to the transesterification zone of the PET plant for use in the transesterification reaction. Additionally, one or more of the streams returned to the distillation zone may contain DMT (r-DMT), which may be separated and reintroduced into the reaction zone of the PET plant.

[0084]

[0089] Turning now to FIG. 4, another portion of a chemical recycling facility including an integrated methanolysis and PET production facility is shown, particularly illustrating the case where the methanolysis facility and the PET production facility share a common distillation zone. As shown in FIG. 4, once the PET waste plastic is subjected to methanolysis in the reaction zone, the methanolysis reactor stream can be separated into light and heavy organic streams in the product separation zone. The heavy organic stream predominantly contains DMT and can be further separated in the heavy organic separation zone, but the light organic stream predominantly contains methanol and EG and can also be separated in one or more distillation towers that separate the methanol and / or EG containing streams from the transesterification and polymerization zone of the PET production facility. These streams may also contain terephthalyl components. In some cases, the shared distillation tower or column may provide an EG enriched stream, a methanol enriched stream or other co-product streams.

[0085]

[0090] When introduced into a shared distillation column, the stream from the methanolysis facility (e.g., the methanolysis reactor product stream) and the stream from the reaction zone of the PET production facility may be combined prior to entering the column or each may be introduced separately. In some cases, one or both streams may be heated or cooled as necessary to maintain the temperature and / or concentration profile throughout the column, and the streams may be vapor phase, liquid phase, or mixed phase (vapor and liquid) streams when introduced into the column.

[0086]

[0091] In some cases, the shared column may be an EG separation column for removing EG (r-EG) from the incoming feed stream(s) and the vapor stream from the PET manufacturing facility may contain predominantly EG. In some cases, the shared column may be a methanol separation column for removing methanol from the incoming feed stream(s) and the vapor stream withdrawn from the PET manufacturing facility (or transesterification zone) may contain predominantly methanol. In some cases, the shared column may be a spray column downstream of a methanolysis reactor and the stream from the PET manufacturing facility may contain r-EG, r-methanol and r-DMT (or r-terephthalyl components).

[0087]

[0092] In some cases, at least a portion of the vapor stream removed from a reaction zone (e.g., transesterification zone and / or polymerization zone) of a PET manufacturing facility can be decanted with water to provide an organic phase and an aqueous phase. Contact with water can help remove at least a portion of the compounds that form the EG azeotrope and may form an azeotrope with EG that is also an azeotrope with water. In some cases, the decanting step (if performed) can remove at least 50 percent, at least 60 percent, at least 70 percent, at least 75 percent, at least 80 percent, at least 90 percent, or at least 95 percent of the compounds that form the EG azeotrope from the PET reaction zone vapor stream introduced into the distillation zone and at least one distillation column therein. If solid stating is performed, an overhead stream from the solid stating zone can also be introduced into the distillation zone and optionally decanted with water prior to introduction.

[0088]

[0093] In some cases, removal of compounds that form EG (and / or water) azeotropes from the PET plant vapor stream (e.g., from transesterification, polymerization, solid stating, if present, or even from crystallization zones) can result in reduced energy usage for one or more distillation columns used to separate streams from the methanolysis and / or PET manufacturing plant.

[0089]

[0094] Additionally or alternatively, in some cases, at least a portion of the vapor streams from the PET reaction zone (or crystallization or solid stating, if present) can be introduced directly into one or more distillation columns of the shared distillation zone, which can help improve energy efficiency. In other cases, at least some or all of these streams may be condensed prior to separation in the distillation zone.

[0090]

[0095] Further, in some cases, as generally shown in Figure 4, the reaction zone of the methanolysis facility and the transesterification zone of the PET facility can share a common catalyst source. For example, this can occur when the same catalyst is used by both reaction zones. The catalyst can be of the same type and can be present in the amounts described herein.

[0091] definition

[0096] It should be understood that the following is not intended to be an exhaustive list of defined terms. In the foregoing description, other definitions may be provided, for example, as they accompany the use of a defined term in context.

[0092]

[0097] As used herein, the terms "a," "an," and "the" mean one or more.

[0098] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be used alone, or any combination of two or more of the listed items can be used. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B combined; A and C combined, B and C combined; or A, B, and C combined.

[0093]

[0099] As used herein, the phrase "at least a portion" includes at least a portion and up to, including an entire amount or period.

[0100] As used herein, the term "chemical recycling" refers to a waste plastic recycling process that involves chemically converting waste plastic polymers into low molecular weight polymers, oligomers, monomers, and / or non-polymer molecules (e.g., hydrogen, carbon monoxide, methane, ethane, propane, ethylene and propylene) that are useful in themselves and / or as feedstocks to another chemical manufacturing process(es).

[0094]

[0101] As used herein, the term "monomer" refers to a polymeric species containing a chain length of less than about three.

[0102] As used herein, the term "oligomer" refers to a species of polymer containing a range of chain lengths from about 7 to about 50.

[0095]

[0103] As used herein, the term "polymer" refers to polymer species that contain a chain length of greater than about 50.

[0104] As used herein, the terms "polyethylene terephthalate" and "PET" include PET homopolymer, PET copolymer and PETG.

[0096]

[0105] As used herein, the term "PET copolymer" refers to PET modified with up to 10 mole percent of one or more added comonomers. For example, the term "PET copolymer" includes PET modified with up to 10 mole percent of isophthalic acid, based on 100 mole percent carboxylic acid. In another example, the term "PET copolymer" includes PET modified with up to 10 mole percent of 1,4-cyclohexanedimethanol (CHDM), based on 100 mole percent diol.

[0097]

[0106] As used herein, the term "residue" refers to a moiety that is a product of a resulting chemical species in a particular reaction scheme or subsequent formulation or chemical product, regardless of whether the moiety is actually derived from that chemical species.

[0098]

[0107] As used herein, the term "co-located" refers to a common physical location and / or characteristic of at least two objects located within one mile of each other.

[0099]

[0108] As used herein, the terms "comprising," "comprises," and "comprise" are open-ended transitional terms used to transition from the subject matter described before the term to one or more elements described after the term, where the element or elements listed after the transitional term are not necessarily the only elements that make up the subject matter.

[0100]

[0109] As used herein, the term "industrial-scale facility" refers to a facility having an average annual feed rate of at least 500 pounds per hour averaged over a year.

[0101]

[0110] As used herein, the term "D90" refers to a specified diameter where 90 percent of the particle distribution has a diameter smaller than the specified diameter and 10 percent has a diameter larger than the specified diameter. To ensure a representative D90 value. The particle sample size should be at least 0.45 kg (1 pound). To determine the D90 of particles in a continuous process, testing should be performed on at least 5 samples taken at equal time intervals over at least 24 hours. Testing for D90 is performed using high-speed photography and computer algorithms that generate particle size distribution. One suitable particle size analyzer for determining D90 values ​​is the Model CPA 4-1 Computerized Particle Analyzer from WS Tyler of Mentor, Ohio.

[0102]

[0111] As used herein, the term "diameter" refers to the maximum chord length of a particle (i.e., its largest dimension).

[0112] As used herein, the term "directly derived" refers to having at least one physical component that originates from waste plastic.

[0103]

[0113] As used herein, the terms "having," "has," and "have" have the same open-ended meaning as "comprising," "comprises," and "comprise" given above.

[0104]

[0114] As used herein, the term "heavy organic methanolysis co-product" refers to a methanolysis co-product having a boiling point greater than that of DMT.

[0115] As used herein, the term "heavy organic solvolysis co-product" refers to a solvolysis co-product that has a higher boiling point than the main terephthalyl product of the solvolysis unit.

[0105]

[0116] As used herein, the terms "including," "include," and "included" have the same open-ended meaning as "comprising," "comprises," and "comprise" given above.

[0106]

[0117] As used herein, the term "indirectly derived" refers to having an allocated recycled content that is i) attributable to waste plastics, but ii) not based on having a physical component that originates from waste plastics.

[0107]

[0118] As used herein, the term "light organic methanolysis co-product" refers to a methanolysis co-product having a boiling point less than DMT.

[0119] As used herein, the term "light organic solvolysis co-product" refers to a solvolysis co-product that has a boiling point less than the primary terephthalyl product of the solvolysis unit.

[0108]

[0120] As used herein, the term "methanolysis co-product" refers to any compound withdrawn from the methanolysis facility that is not dimethyl terephthalate (DMT), ethylene glycol (EG), or methanol.

[0109]

[0121] As used herein, the terms "mixed plastic waste" and "MPW" refer to a mixture of at least two types of waste plastics, including, but not limited to, the following plastic types: polyethylene terephthalate (PET), one or more polyolefins (PO), and polyvinyl chloride (PVC).

[0110]

[0122] As used herein, the term "molecular reforming" refers to the conversion of a carbon-containing feed to syngas (CO, CO2, and H2). Molecular reforming encompasses both steam reforming and partial oxidation (POX) gasification.

[0111]

[0123] As used herein, "PET" refers to a homopolymer of polyethylene terephthalate, or polyethylene terephthalate modified with a modifier, or polyethylene containing residues or moieties other than ethylene glycol and terephthalic acid, such as isophthalic acid, 1,4-cyclohexanedicarboxylic acid, diethylene glycol, TMCD (2,2,4,4-tetramethyl-1,3-cyclobutanediol), CHDM (cyclohexanedimethanol), propylene glycol, isosorbide, 1,4-butanediol, 1,3-propanediol, and / or NPG (neopentyl glycol). It means terephthalate, or polyesters having terephthalate repeat units (and whether or not they contain ethylene glycol based repeat units) and one or more residues or moieties of TMCD (2,2,4,4-tetramethyl-1,3-cyclobutanediol), CHDM (cyclohexanedimethanol), propylene glycol, or NPG (neopentyl glycol), isosorbide, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-butanediol, 1,3-propanediol, and / or diethylene glycol, or combinations thereof.

[0112]

[0124] As used herein, the term "PET solvolysis" refers to a reaction in which a polyethylene terephthalate-containing plastic feed is chemically decomposed in the presence of a solvent to form primarily terephthalyl products and / or primarily glycol products.

[0113]

[0125] As used herein, the term "physical recycling" (also known as "mechanical recycling") refers to a process of recycling waste plastics that includes melting the waste plastics and forming the molten plastics into new intermediate products (e.g., particles or sheets) and / or new final products (e.g., bottles). Generally, physical recycling does not substantially change the chemical structure of the plastic, although some degradation is possible.

[0114]

[0126] As used herein, the term "predominantly" means greater than 50 weight percent. For example, a propane-predominant stream, composition, feedstock or product is a stream, composition, feedstock or product that contains greater than 50 weight percent propane.

[0115]

[0127] As used herein, the term "pyrolysis" refers to the thermal decomposition of one or more organic materials at elevated temperatures in an inert (i.e., substantially oxygen-free) atmosphere.

[0116]

[0128] As used herein, the terms "recycled fraction" and "r-fraction" refer to being or including a composition that is derived directly and / or indirectly from waste plastics.

[0117]

[0129] As used herein, the term "remotely located" refers to a distance of at least 8.0 km (5 miles), at least 16 km (10 miles), at least 80 km (50 miles), at least 161 km (100 miles), at least 805 km (500 miles), or at least 1609 km (1000 miles) between two facilities, sites, or reactors.

[0118]

[0130] As used herein, "solid state polymerization" refers to a process in which polymer chain length is increased by heating the polyester in the substantial absence of oxygen and water. During solid state polymerization, the polymer is in a solid form and is not in a molten phase.

[0119]

[0131] As used herein, the term "solvolysis" or "ester solvolysis" refers to a reaction in which an ester-containing feed is chemically decomposed in the presence of a solvent to form primarily carboxyl products and / or primarily glycol products. Examples of solvolysis include hydrolysis, alcoholysis, and ammonolysis.

[0120]

[0132] As used herein, the term "solvolysis co-product" refers to any compound withdrawn from a solvolysis unit that is not the primary carboxyl (terephthalyl) product of the solvolysis unit, the primary glycol product of the solvolysis unit, or the primary solvent fed to the solvolysis unit.

[0121]

[0133] As used herein, the term "terephthalyl" refers to the following group:

[0122] [ka] It refers to a molecule comprising:

[0123]

[0134] As used herein, the term "primary terephthalyl" refers to the main or important terephthalyl product recovered from a solvolysis unit.

[0135] As used herein, the term "glycol" refers to a moiety that contains two or more --OH functional groups per molecule.

[0124]

[0136] As used herein, the term "primary glycol" refers to the primary glycol product recovered from the solvolysis unit.

[0137] As used herein, the terms "waste plastic" and "plastic waste" refer to used, scrap and / or discarded plastic materials. Waste plastics fed to chemical recycling facilities may be unprocessed or partially processed.

[0125] Additional claims in support of the description - First embodiment

[0138] In a first embodiment of the present technology, a method for producing recycled polyethylene terephthalate (r-PET) is provided, the method comprising: (a) depolymerizing waste plastics predominantly comprising polyethylene terephthalate (PET) in a methanolysis reactor of a methanolysis facility to form at least recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT); (b) reacting the r-EG and / or r-DMT in a reaction zone of a PET production facility to form a recycled PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.65 dL / g; (c) pelletizing at least a portion of the r-PET polymer melt to form r-PET particles; and (d) crystallizing at least a portion of the r-PET particles to form crystalline r-PET particles.

[0126]

[0139] The first embodiment described in the preceding paragraph may also include one or more of the additional aspects / features listed in the following bulleted paragraphs. Each of the following additional features of the first embodiment may be a stand-alone feature or may be combined with one or more of the other additional features to the extent not inconsistent. Furthermore, the following bulleted paragraphs may be viewed as features of dependent claims with the level of dependency indicated by the degree of indentation in the bulleted list (i.e., a feature that is indented further than the feature(s) listed above it is considered to be dependent on the feature(s) listed above it). The reaction of step (b) further comprises reacting non-recycled EG and / or non-recycled DMT. The r-PET polymer melt withdrawn from the reaction zone has a trimer concentration of less than 1 weight percent (0.5, 0.1) based on the total weight of the r-PET polymer melt. further comprising processing the mixed plastic waste in a plastics processing facility to provide predominantly PET waste plastic; and depolymerizing the PET waste plastic in step (a).

[0127] The processing step includes classifying and / or separating the mixed waste plastics. ○ PET waste plastic contains at least 75 (80, 85, 90, 95 or 99) percent by weight of PET. The depolymerization is carried out in the presence of methanol.

[0128] At least a portion of the methanol used for depolymerization originates from PET manufacturing facilities. further comprising the steps of pelletizing at least a portion of the r-PET polymer melt via underwater cutting to provide r-PET particles, and crystallizing at least a portion of the r-PET particles in step (c). At least part of the crystallization is latent heat crystallization. Further comprising the step of stripping the r-PET with a gas stream after crystallization to remove acetaldehyde (AA).

[0129] The gas stream is selected from the group consisting of air, carbon dioxide and nitrogen. · r-PET is not a solid-state polymer. Crystalline r-PET contains spheroidal particles.

[0130] o Crystalline r-PET comprises a plurality of spheroidal particles having an intrinsic viscosity (It.V.) at the surface of the particle that is less than 0.25 dL / g higher than the It.V. at the center of the particle. The inherent viscosity (IV) of the r-PET is at least 0.70 dL / g (0.72, 0.73, 0.75, 0.77, 0.80, 0.82, 0.85) and / or no more than 1.05 dL / g, no more than 1.0 dL / g, no more than 0.95 dL / g (0.90, 0.85, 0.83). The r-PET polymer melt has an inherent viscosity (IV) in the range of 0.73-0.85 dL / g. the reacting step includes subjecting the r-EG and r-DMT to transesterification to produce recycled PET oligomers (r-PET oligomers), and then polymerizing the r-PET oligomers to form an r-PET polymer melt.

[0131] The transesterification reaction is carried out at a temperature of at least 175, 180, 185, 190, 195, 200, 205, 210, 215, 220°C and / or up to 350, 345, 340, 335, 330, 325 or 320°C.

[0132] The transesterification reaction is carried out at a pressure within 7 kPa (1 psig), 14 kPa (2 psig), 34 kPa (5 psig) or 69 kPa (10 psig) of atmospheric pressure.

[0133] The transesterification reaction is carried out at a pressure of at least 0 kPa (0 psig), 34 kPa (5 psig), 69 kPa (10 psig), 172 kPa (25 psig), 345 kPa (50 psig) or 517 kPa (75 psig) and / or not more than 689 kPa (100 psig), not more than 517 kPa (75 psig), not more than 345 kPa (50 psig), not more than 172 kPa (25 psig), not more than 138 kPa (20 psig), not more than 69 kPa (10 psig) or not more than 34 kPa (5 psig).

[0134] The ratio of EG to DMT introduced into the transesterification reactor is at least 1.1 (1.2:1, 1.3:1, 1.4:1 or 1.5:1) and / or not more than 5:1 (4:1, 3.5:1 or 3:1).

[0135] The conversion of DMT after transesterification is at least 85 (90, 95, 97 or 99) percent. The polymerization is carried out at a temperature of at least 240 (245, 250, 255 or 260)°C and / or up to 340°C (335, 330, 325, 320, 315, 310 or 300).

[0136] The polymerization is carried out at a pressure below atmospheric pressure or below 750, 500, 250, 100, 50 or 20 Pa. The polymerization is carried out in the presence of a non-antimony catalyst.

[0137] The mass transfer rate during polymerization is at least 1.5 number average degree of polymerization (DP) / min. The reacting step is carried out in a reactive distillation column. The reacting step is carried out in a CSTR, a pipe reactor, a plug flow reactor, a reactive distillation column, a falling film reactor, a horizontally oscillating reactor, a vertical gravity driven reactor, or a combination thereof. · r-PET contains at least one IR absorber additive.

[0138] The IR absorber additive is selected from the group consisting of black iron oxide, graphite, reduced antimony catalyst, carbon black and titanium nitride. ○ The IR absorber additive is present in an amount of at least 0.10 (0.5, 1, 1.5) and / or no more than 5 weight percent (3, 2, 1, 0.5) based on the weight of the r-PET. the reacting step comprises further reacting the EG and DMT with one or more comonomers.

[0139] o The one or more comonomers are selected from the group consisting of isophthalic acid, dimethyl isophthalate, neopentyl glycol, 1,4-cyclohexanedimethanol (1,4-CHDM), diethylene glycol, and combinations thereof.

[0140] Comonomers are present in r-PET in a total amount of at least 5 (10, 15, 20, 25, 30, 35) mole percent and / or no more than 50 mole percent (45, 40, 35, 30, 25, 20, 15) based on the total moles of diester or diol components. The process is a continuous process. · The process is an industrial-scale process, with an average production rate of r-PET from the PET manufacturing facility of at least 500 pounds (227 kg) per hour. · Methanolysis and PET manufacturing facilities will share the same location. · r-PET contains diethylene glycol (DEG) residues in an amount of 1 mole percent or less (0.75, 0.50, 0.45, 0.40) based on the total diol content. - r-PET has a carboxyl value of less than 15 meq / kg (10, 7, 5, 2). The r-PET contains residues of 100 ppm or less of one or more metals selected from the group consisting of Mn, Zn, and combinations thereof. The r-PET has an intrinsic viscosity in the range of 0.65-1.10 dL / g, and the r-PET comprises a plurality of spheroidal particles having an intrinsic viscosity (It.V.) at the surface of each particle that is less than 0.25 dL / g higher than the It.V. at the center of the particle. · r-PET has an acetaldehyde content of 75 ppm or less (50, 25, 10, 5). r-PET has a diester component that contains at least 75 (80, 85, 90, 95 or 99) mole percent of DMT residues, based on the total moles of the diester component, and a diol component that contains at least 75 (80, 85, 90, 95 or 99) mole percent of EG residues, based on the total moles of the diol component, and the r-PET contains 0.5 mole percent or less (0.1, 0.05) of terephthalic acid residues, based on the total moles of the diester component.

[0141] Additional claims in support of the description - second embodiment

[0140] In a second embodiment of the present technology, a method for producing recycled polyethylene terephthalate (r-PET) is provided, comprising: (a) transesterifying recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT) in a transesterification reaction zone of a PET production facility to form recycled PET oligomers (r-PET oligomers); (b) polycondensing at least a portion of the r-PET oligomers to obtain recycled PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.65 dL / g; (c) pelletizing at least a portion of the r-PET polymer melt via underwater cutting to form recycled PET (r-PET) particles; and (d) crystallizing the r-PET particles to form crystalline r-PET particles.

[0142]

[0141] The second embodiment described in the preceding paragraph may also include one or more of the additional aspects / features listed in the following bulleted paragraphs. Each of the following additional features of the second embodiment may be a stand-alone feature or may be combined with one or more of the other additional features to the extent not inconsistent. Furthermore, the following bulleted paragraphs may be viewed as features of dependent claims with the level of dependency indicated by the degree of indentation in the bulleted list (i.e., a feature that is indented further than the feature(s) listed above it is considered to be dependent on the feature(s) listed above it). The crystallization in step (d) comprises latent heat crystallization. The mass transfer rate during the polycondensation of step (b) is at least 1.5 number average degrees of polymerization (DP) per minute. The inherent viscosity (IV) of the r-PET polymer melt is at least 0.67 (0.70, 0.72, 0.75, 0.77, 0.80, 0.82) dL / g and / or not more than 1.05 dL / g (1.0, 0.95, 0.90, 0.85, 0.82). further comprising the step of stripping the crystalline r-PET particles to remove residual acetaldehyde (AA). Crystalline r-PET particles are spheroidal. · The crystalline r-PET particles are not solid-state polymerized. Crystalline r-PET comprises a plurality of spheroidal particles having an intrinsic viscosity (It.V.) at the surface of the particle that is less than 0.25 dL / g higher than the It.V. at the center of the particle. the crystalline r-PET particles have an inherent viscosity (IV) that differs from the r-PET polymer melt pelletized in step (c) by no more than 0.10 dL / g. · r-PET contains diethylene glycol (DEG) residues in an amount of 1 mole percent or less (0.75, 0.50, 0.45, 0.40) based on the total diol content. - r-PET has a carboxyl value of less than 15 meq / kg (10, 7, 5, 2). The r-PET contains residues of 100 ppm or less of one or more metals selected from the group consisting of Mn, Zn, and combinations thereof. The transesterification reaction is carried out at a temperature of at least 175, 180, 185, 190, 195, 200, 205, 210, 215, 220°C and / or up to 350, 345, 340, 335, 330, 325 or 320°C. The transesterification reaction is carried out at a pressure within 7 kPa (1 psig), 14 kPa (2 psig), 34 kPa (5 psig) or 69 kPa (10 psig) of atmospheric pressure. The transesterification reaction is carried out at a pressure of at least 0 kPa (0 psig), 34 kPa (5 psig), 69 kPa (10 psig), 172 kPa (25 psig), 345 kPa (50 psig) or 517 kPa (75 psig) and / or not more than 689 kPa (100 psig), not more than 517 kPa (75 psig), not more than 345 kPa (50 psig), not more than 172 kPa (25 psig), not more than 138 kPa (20 psig), not more than 69 kPa (10 psig) or not more than 34 kPa (5 psig). The ratio of EG to DMT introduced into the transesterification reactor is at least 1.1 (1.2:1, 1.3:1, 1.4:1 or 1.5:1) and / or not more than 5:1 (4:1, 3.5:1 or 3:1). The conversion of DMT after transesterification is at least 85 (90, 95, 97 or 99) percent. The polycondensation in step (b) is carried out at a temperature of at least 240 (245, 250, 255 or 260)°C and / or at most 340°C (335, 330, 325, 320, 315, 310 or 300). The polycondensation in step (b) is carried out at subatmospheric pressure or at a pressure below 750, 500, 250, 100, 50 or 20 Pa. further comprising the step of depolymerizing the PET waste plastic in a methanolysis facility to provide recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT), wherein the r-EG and / or r-DMT transesterified in step (a) comprises at least a portion of the r-EG and / or r-DMT from the methanolysis facility.

[0143] Prior to depolymerization, further comprising the steps of processing the mixed waste plastics to provide predominantly PET waste plastics, and depolymerizing at least a portion of the predominantly PET waste plastics.

[0144] ■ The processing step includes a step of classifying and / or separating the mixed waste plastics. The process is a continuous process. The process is an industrial-scale process, with an average production rate of r-PET from the PET manufacturing facility of at least 227 kg per hour (500 pounds per hour (lb / h)). · Methanolysis and PET manufacturing facilities will share the same location. The r-PET has an intrinsic viscosity in the range of 0.65-1.10 dL / g, and the r-PET comprises a plurality of spheroidal particles having an intrinsic viscosity (It.V.) at the surface of each particle that is less than 0.25 dL / g higher than the It.V. at the center of the particle. · r-PET has an acetaldehyde content of 75 ppm or less (50, 25, 10, 5). r-PET has a diester component that contains at least 75 (80, 85, 90, 95 or 99) mole percent of DMT residues, based on the total moles of the diester component, and a diol component that contains at least 75 (80, 85, 90, 95 or 99) mole percent of EG residues, based on the total moles of the diol component, and the r-PET contains 0.5 mole percent or less (0.1, 0.05) of terephthalic acid residues, based on the total moles of the diester component.

[0145] The claims are not limited to the disclosed embodiments.

[0142] The above preferred embodiments of the present invention should be used only as an explanation, and should not be used in a limiting sense to interpret the scope of the present invention. Modifications of the above exemplary embodiments can be easily made by those skilled in the art without departing from the spirit of the present invention.

[0146]

[0143] The inventors hereby express their intention to rely on the doctrine of equivalents to determine and evaluate the reasonable and fair scope of the present invention with respect to any arrangement that does not materially depart from the literal scope of the present invention as set forth in the following claims.

Claims

1. A method for producing recycled polyethylene terephthalate (r-PET), comprising the steps of: (a) depolymerizing waste plastics, predominantly comprising polyethylene terephthalate (PET), in a methanolysis reactor of a methanolysis facility to form at least recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT); (b) reacting the r-EG and / or r-DMT in a reaction zone of a PET manufacturing facility to form a recycle PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.65 dL / g; (c) pelletizing at least a portion of the r-PET polymer melt to form r-PET particles; (d) crystallizing at least a portion of the r-PET particles to form crystalline r-PET particles. A method comprising:

2. 10. The method of claim 1, wherein the pelletizing in step (c) comprises underwater cutting.

3. 10. The method of claim 1, wherein the crystallization in step (d) comprises latent heat crystallization.

4. 10. The method of claim 1, further comprising the step of stripping the r-PET particles with a gas stream to remove acetaldehyde (AA) after the crystallization of step (d), wherein the stripped r-PET particles have an AA concentration of less than 10 ppm.

5. 10. The method of claim 1, further comprising withdrawing a stream comprising methanol from a reaction zone of the PET facility and introducing at least a portion of the methanol recovered from said stream into the methanolysis reactor.

6. 2. The method of claim 1, wherein the reacting in step (b) comprises subjecting the r-EG and r-DMT to a transesterification reaction to produce recycle PET oligomers (r-PET oligomers) and then polymerizing at least a portion of the r-PET oligomers to form the r-PET polymer melt, wherein the mass transfer rate during the polymerization is at least 1.5 number average degree of polymerization (DP) / minute (min).

7. 2. The method of claim 1, wherein the r-PET contains greater than 0.50 mole percent, less than or equal to 0.25 mole percent, less than or equal to 0.10 mole percent, or less than or equal to 0.05 mole percent of terephthalic acid residues, based on the total moles of the diester component.

8. 2. The method of claim 1, further comprising the steps of processing mixed plastic waste in a plastics processing facility to provide predominantly PET waste plastics, and depolymerizing the PET waste plastics in step (a), wherein the processing comprises classifying and / or separating the mixed waste plastics, and wherein the PET waste plastics comprises at least 75 (80, 85, 90, 95 or 99) weight percent PET.

9. A method for producing recycled polyethylene terephthalate (r-PET), comprising the steps of: (a) transesterifying recycle ethylene glycol (r-EG) and recycle dimethyl terephthalate (r-DMT) in a transesterification reaction zone of a PET production facility to form recycle PET oligomers (r-PET oligomers); (b) polycondensing at least a portion of the r-PET oligomers to provide a recycled PET polymer melt (r-PET polymer melt) having an inherent viscosity (IV) of at least 0.65 dL / g; (c) pelletizing at least a portion of the r-PET polymer melt via underwater cutting to form recycled PET (r-PET) particles; (d) crystallizing the r-PET particles to form crystalline r-PET particles; A method comprising:

10. 10. The method of claim 9, wherein the crystallization in step (d) comprises latent heat crystallization.

11. 10. The method of claim 9, wherein the r-PET polymer melt has an IV in the range of 0.70 to 0.85 dL / g, and the crystalline r-PET particles have an IV that differs from the r-PET polymer melt pelletized in step (c) by no more than 0.10 dL / g.

12. 10. The method of claim 9, further comprising the step of depolymerizing predominantly PET waste plastic in a methanolysis facility to provide recycled ethylene glycol (r-EG) and recycled dimethyl terephthalate (r-DMT), wherein the r-EG and / or r-DMT transesterified in step (a) comprises at least a portion of the r-EG and / or r-DMT from the methanolysis facility.

13. 13. The method of claim 12, further comprising processing mixed waste plastics to provide predominantly PET waste plastics prior to the depolymerization, said processing comprising classification and / or separation of the mixed waste plastics.

14. The method of any one of claims 1 to 13, wherein the crystalline r-PET particles are not solid state polymerized.

15. The method of any one of claims 1 to 13, wherein the crystalline r-PET particles comprise spheroidal particles.

16. 16. The method of claim 15, wherein at least a portion of the crystalline r-PET has an intrinsic viscosity (It.V.) at the surface of the particle that is less than 0.25 dL / g higher than the It.V. at the center of the particle.

17. 14. The method of any one of claims 1 to 13, wherein the crystalline r-PET particles have a diester component comprising at least 95 mole percent of dimethyl terephthalate (DMT) residues, based on the total moles of the diester component, and a diol component comprising at least 75 mole percent of ethylene glycol (EG) residues, based on the total moles of the diol component, and the crystalline r-PET particles comprise 0.5 mole percent or less of terephthalic acid residues, based on the total moles of the diester component.

18. The crystalline r-PET particles have the following characteristics (i) to (v): (i) 0.1 mol % or less of the following components: residues of methyl 4-formylbenzoate, dimethyl 1,4-cyclohexanedicarboxylate, dimethyl phthalate, methyl isopropyl terephthalate, methyl propyl terephthalate, and methyl isobutyl terephthalate; (ii) at least 0.1 mole % of the residues of the following compounds: diisobutyl phthalate, methyl 4-ethylbenzoate, and methyl 4-vinylbenzoate; (iii) Cobalt (Co) and bromide (Br) not exceeding 100 ppm; (iv) a methyl end concentration of at least 5% and no more than 30% based on the total end groups; and (v) less than or equal to 0.1 mole percent of residues of 4-carboxybenzaldehyde and 9-fluorenone-2,6-dicarboxylic acid, based on the total moles of said polyester; The method according to any one of claims 1 to 13, further comprising at least one of:

19. 14. The method of any one of claims 1 to 13, wherein the method is an industrial scale method and the production rate of crystalline r-PET particles from the PET manufacturing facility is at least 500 pounds per hour (lb / h).

20. 14. The process according to any one of claims 1 to 13, which is a continuous process.

Images