EA040205B1 - METHOD FOR MANUFACTURING VOLUME CONTINUOUS ELEMENTARY CARPET FIBER FROM DYED RECORDED POLYETHYLENE TEREPHTHALATE - Google Patents

Description

Technical field

The present invention relates to the field of using recycled polymer. More specifically, the present invention is directed to a process for making bulk continuous filament carpet fiber from dyed recycled PET (polyethylene terephthalate), which includes both colorless and dyed PET.

State of the art

Because pure raw PET polymer is more expensive than recycled PET polymer, and because of the environmental benefits associated with using recycled polymer, it would be desirable to be able to produce bulk continuous carpet filament and other products from 100% recycled PET polymer ( e.g. PET resin from used PET bottles).

Some documents of the prior art relate to the use of recycled polymer for the manufacture of bulk continuous elementary carpet fibers. For example, US 2011/177283 A1 discloses a process for forming PET fibers for carpet, in which the fibers are specifically suitable for carpet use in the automotive industry. Also, this document does not say anything about the use of a mixture of colorless and colored recycled PET flakes. In addition, the most closely related document US 2015076725 A1 relates to a method for processing polymers and other plastics, which includes (A) shredding recycled PET bottles (or other suitable recycled polymer) into a group of flakes; (B) washing the flakes; (C) detecting and removing impurities, including impure flakes, from a group of flakes; (D) passing the group of flakes through the MRS extruder while maintaining the pressure within the MRS portion of the MRS extruder below about 5 mbar; (E) passing the resulting polymer melt through at least one filter having a nominal micron value of less than about 50 microns; and (F) preparing the polymer melt for processing into a new product. However, this solution requires intensive preparation and purification of said polymer flakes in order to obtain the purified and essentially colorless flakes used therein. In addition, the method according to this decision does not take into account the amount of colored and colorless flocculent particles from recycled polyethylene terephthalate (PET).

The essence of the invention

One of the technical problems solved by the present invention is the manufacture of a relatively light colored yarn, which includes dyed recycled PET flake particles. Comparatively light colored yarn can be easily dyed later in the process. The inclusion of colored recycled PET flakes requires less processing of recycled PET flakes.

In specific embodiments, the proposed method for manufacturing bulk continuous filamentary carpet fiber comprises providing a multi-screw extruder that includes (1) a first satellite screw extruder comprising a first satellite screw rotating about a central axis of the first satellite screw; (2) a second satellite screw extruder comprising a second satellite screw rotating about a central axis of the second satellite screw; and (3) a pressure control system configured to maintain pressure within the first and second satellite screw extruders in the range of approximately 0-5 mbar. In specific embodiments, this method further comprises (1) using a pressure control system to reduce the pressure within the first and second satellite screw extruders to a range of approximately 0-5 mbar; (2) providing a plurality of polymeric flake particles comprising up to about 10% colored flake particles from recycled polyethylene terephthalate (PET) with a balance of essentially colorless flake particles from recycled PET; (3) providing one or more dye concentrates; (4) adding one or more color concentrates to a plurality of polymer flakes such that the resulting mixture contains about 0-3% by weight of one or more color concentrates; (4) while maintaining the pressure within the first and second satellite screw extruders in the range of approximately 0-5 mbar, passing a plurality of polymer flakes and one or more dye concentrates through a multi-screw extruder in order to form a polymer melt so that (a) the first part of the polymer the melt passed through the first satellite screw extruder and (b) the second part of the polymer melt passed through the second satellite screw extruder; and after the step of passing the polymer melt through a multi-screw extruder, spinning the recycled polymer into a bulky continuous carpet filament.

Brief description of the drawings

After describing the various embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale.

Fig. 1 depicts a process flow, in accordance with one particular embodiment, for the manufacture of a bulky continuous unit carpet fiber.

Fig. 2 is a perspective view of an exemplary MRS extruder that is suitable for use in the process shown in FIG. 1.

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Fig. 3 is a cross section of an exemplary MRS section of the MRS extruder shown in FIG. 2.

Fig. 4 is a process flow depicting polymer flow through an MRS extruder and filtration system in accordance with one particular embodiment.

Fig. 5 is a high-level flowchart of a method for manufacturing a bulky continuous filament carpet fiber in accordance with various embodiments.

Detailed description of various embodiments

Next, various embodiments will be described in more detail. It should be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure is complete and complete and fully conveys the scope of the present invention to those skilled in the art. Like reference numerals refer to like elements throughout the drawings.

I. Brief review.

The following describes new processes for making fiber from recycled polymer (eg, recycled PET polymer). In various embodiments, this new process (1) is more efficient than prior processes in removing contaminants and water from the recycled polymer; and/or (2) does not require repeated melting and cooling of the polymer, as in previous processes. In at least one embodiment, this improved process results in a recycled PET polymer having a polymer quality that is high enough so that the PET polymer can be used in the production of bulk continuous carpet filament from 100% recycled PET (e.g., 100 % PET from used PET bottles). In specific embodiments, the recycled PET polymer has an intrinsic viscosity of at least about 0.79 dl/g (eg, from about 0.79 dl/g to about 1.00 dl/g).

II. More detailed discussion.

The manufacturing process for BCF (bulky continuous filament) according to one particular embodiment may comprise three steps: (1) making PET polymer flake particles from used bottles; (2) passing these flocs through an extruder which melts the flocs and purifies the resulting PET polymer; and (3) feeding the purified polymer to a spinning machine which converts the polymer into a continuous filament for use in carpet production. These three stages are described in more detail below.

Stage 1.

Preparation of PET polymer flakes from used bottles.

In one particular embodiment, the step of preparing PET polymer flake particles from used bottles comprises (A) sorting the used PET bottles and grinding the bottles into flake particles; (B) washing the flocs; (C) identification and removal of any impurities or contaminated flocs.

A. Sorting of used PET bottles and grinding bottles into flaky particles.

In particular embodiments, stacks of colorless and colored used PET bottles (eg, trash) (or other containers) obtained from various disposal sources constitute used PET containers for use in the process. In other embodiments, the source of used PET containers may be returnable deposit bottles (eg, PET bottles whose price includes a deposit that is returned to the customer upon return of the used bottle). Waste or returnable used or recycled containers may contain a small amount of foreign matter. Contaminants in containers may include, for example, non-PET polymeric contaminants (e.g. PVC, PLA, PP, PE, PS, PA, etc.), metal (e.g. ferrous and non-ferrous metals), paper, cardboard, sand, glass, or other unwanted materials that may enter containers when collecting recycled PET. Non-PET contaminants can be removed from the desired PET components, for example, through one or more of the various processes described below.

In specific embodiments, small components and debris (eg, components and debris larger than 2 inches) are removed from whole bottles using a rotating catcher screen. Various metal removal magnets and eddy current systems can be included in the process to remove any metal contaminants. Near-infrared optical sorting equipment, such as the NRT Multi Sort Infrared Machine from Bulk Handling Systems Company of Eugene, OR or the Spyder Infrared Machine from National Recovery Technologies of Nashville, TN, can be used to remove any polymer soils that can be mixed with PET flakes (eg PVC, PLA, PP, PE, PS and PA). In addition, automated x-ray sorting equipment such as the VINYLCYCLE machine from National Recovery Technologies, Nashville, Tenn., can be used to remove remaining contaminants from the PVC.

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In particular embodiments, binary separation of uncolored materials from colored materials is achieved using automated color sorting equipment equipped with a camera-based detection system (eg, Multisort ES machine manufactured by National Recovery Technologies, Nashville, Tenn.). In various embodiments, manual sorters are placed at various points along the line to remove contaminants not removed by the sorting machine, as well as any stained bottles. In specific embodiments, the graded material is passed through a granulation step (eg, using a 50B Granulator manufactured by Cumberland Engineering Corporation, NewBerlin, Wisconsin) to reduce the size (eg, grind) of the bottles to less than half an inch. In various embodiments, bottle labels are removed from the resulting dirty flakes (eg, PET flakes formed during the granulation step) by an air separation system prior to the washing process.

B. Washing of flocs.

In specific embodiments, the dirty flakes are then mixed in a series of wash tanks. As part of the washing process, in various embodiments, an aqueous density separation is used to separate any olefin caps (which may, for example, be present in dirty flakes as residue from recycled PET bottles) from the higher density PET flakes. In specific embodiments, the implementation of the flake particles are washed in a hot bath of caustic soda with a temperature of approximately 190°F. In specific embodiments, the sodium hydroxide concentration in the caustic soda bath is maintained at about 0.6-1.2%. In various embodiments, soapy surfactants as well as defoamers are added to the caustic soda bath, for example, to further enhance the separation and cleanup of the flake particles. The double rinse system then rinses the caustic soda away from the flaky particles.

In various embodiments, the flocculated particles are centrifugally dehydrated and then dried with hot air to at least substantially remove surface moisture. The resulting clean flake particles are then treated with an electrostatic separation system (for example, an electrostatic separator manufactured by Carpco, Inc. of Jacksonville, Florida) and a metal detection system (for example, an MSS metal sorting system) to further remove any metal contaminants remaining in flaky particles. In specific embodiments, the air separation step removes any remaining labels from the pure flocs. In various embodiments, the flake particles are then passed through a flake color sorting step (eg, using an OPTIMIX machine manufactured by TSM Control Systems, Dundalk, Ireland) to remove any colored contaminants remaining in the flake particles. In various embodiments, an electro-optical flake sorter based at least in part on Raman technology (e.g., Powersort 200 manufactured by Unisensor Sensorsysteme GmbH, Karlsruhe, Germany) performs a final polymer separation to remove any non-PET polymers, remaining in flaky particles. This step may also further remove any remaining metallic soils and colored soils.

In various embodiments, the combination of these steps provides substantially clear (e.g., colorless) flake particles from PET bottles containing less than about 50 ppm PVC (e.g., 25 ppm PVC) and less than about 15 hours ./million metals for use in the subsequent extrusion process described below.

C. Identification and removal of impurities and contaminated flakes.

In specific embodiments, after the flakes have been washed, they are placed on a conveyor and scanned by the high speed laser system 300. In various embodiments, the specific lasers that make up the high speed laser system 300 are configured to detect the presence of specific contaminants (e.g., PVC or aluminium). Fluff particles that are identified as essentially non-PET can be blown out of the main fluff stream using air ejectors. In various embodiments, the non-PET flake content obtained is less than 25 ppm.

In various embodiments, the system is configured to ensure that the PET polymer to be processed into continuous filament is substantially free of water (eg, completely free of water). In one particular embodiment, the flocs are placed in a preconditioner for about 20-40 minutes (eg, about 30 minutes), during which time the preconditioner blows surface water off the flocs. In specific embodiments, the implementation of the pore water remains within the flocculent particles. In various embodiments, these moist flocculent particles (for example,

- 3 040205 floc particles containing pore water) can then be fed into an extruder (for example, as described below for stage 2), which includes a vacuum unit designed, among other things, to remove pore water that remains in the floc particles after the above described fast drying process.

Stage 2

Using an extrusion system to melt and clean PET flakes.

In particular embodiments, an extruder is used to convert the wet flakes described above into molten recycled PET polymer and perform a series of refining processes to prepare the polymer to be converted into BCF for carpets. As noted above, in various embodiments, upon completion of step 1, the recycled PET polymer floc particles are wet (e.g., surface water is substantially removed (e.g., completely removed) from the floc particles, but pore water remains in the floc particles). In specific embodiments, these wet flakes are fed to a multi-screw (MRS) extruder 400. In other embodiments, the wet flakes are fed to any other suitable extruder (e.g., twin-screw extruder, multi-screw extruder, planetary extruder, or any other suitable extrusion system). An exemplary MRS extruder 400 is shown in FIG. 2 and 3. One specific example of such an MRS extruder is described in US 2005/0047267 Extruder for the manufacture of molten plastic materials, published March 3, 2005, which is incorporated herein by reference.

As can be understood from these drawings, in particular embodiments, the MRS extruder includes a first single screw extruder section 410 for feeding material into the MRS section 420 and a second single screw extruder section 440 for conveying material from the MRS section.

In various embodiments, wet flakes are fed directly to the MRS extruder 400 substantially immediately (eg, immediately) after the washing step described above (eg, without drying the flakes or allowing the flakes to dry). In particular embodiments, a system that feeds wet flake particles directly to the MRS extruder 400 substantially immediately (eg, immediately) after the wash step described above can consume approximately 20% less energy than a system that substantially dries the flake particles completely dry. before extrusion (eg, a system that dries the flakes by passing hot air over wet flakes for an extended period of time). In various embodiments, a system that feeds wet flake particles directly to the MRS extruder 400 substantially immediately (e.g., immediately) after the washing step described above does not need to wait (e.g., up to 8 hours) typically required for the flakes to dry completely. particles (eg, removing all surface water and pore water from flocculent particles).

Fig. 4 depicts a process flow that illustrates the various processes performed by the MRS extruder 400 in one particular embodiment. In the embodiment shown in this drawing, wet flake particles are first fed through the first single screw section 410 MRS extruder, which can, for example, generate sufficient heat (for example, due to shear) in order to at least substantially melt ( e.g. melt) wet flaky particles.

In the embodiment shown in this figure, the system is further configured to add the dye concentrate solution 415 to the flocs (e.g., wet flakes) prior to feeding the flocs to the first single screw section 410. In particular embodiments, the dye concentrate solution 415 may include includes any suitable dye concentrate which can, for example, give a particular color to the polymer fiber after extrusion. In particular embodiments, the colorant concentrate may comprise a granular colorant concentrate as well as a carrier resin that can, for example, bind the colorant to the polymer. In various embodiments, the addition of a dye concentrate to the flake prior to extrusion may result in a polymeric continuous filament that is at least partially impregnated (eg impregnated) with a color pigment. In particular embodiments, a carpet made from a solution-dyed continuous filament can be highly resistant to fading from sunlight, ozone, harsh cleaning agents such as bleach, or other factors.

In various embodiments, the system is configured to control the amount of dye concentrate solution 415 added to the flake prior to feeding the flake to the first single screw section 410. In specific embodiments, the system is configured to add approximately 2-3 wt. . In other embodiments, the implementation of the system is configured to add approximately 0-3 wt.% concentrate of the dye. In other embodiments, the system is configured to add up to about 6% by weight of dye concentrate to the polymer flake prior to extrusion. In some embodiments, the system is configured to add about 1-3% by weight of dye concentrate to the polymer flake. In other embodiments, the system is configured to add any suitable amount of dye concentrate to the polymer flake in order to achieve a particular color of the molten polymer (and ultimately the polymer fiber) after extrusion.

Although in the embodiment shown in this drawing, the dye concentrate solution 415 is shown as being added to the flake polymer prior to feeding the flake particles through the first single screw extruder section 410, it should be understood that in other embodiments, the dye concentrate solution 15 may be added during any other appropriate phase of the process described in this document. For example, in various embodiments, the system is configured to add the dye concentrate solution 415 after the flake polymer is extruded by the first single screw extruder section 410, but before the resulting polymer melt is fed through the MRS extruder section 420, discussed below. In other embodiments, the system may add the dye concentrate solution 415 after the flakes have passed through the MRS section 420 of the extruder, before the polymer melt passes through the second single screw section 440, discussed below. In other embodiments, the system may add the dye concentrate solution 415 while the flakes and/or polymer melt are being extruded in the first single screw section 410 of the extruder, the MRS section 420, the second single screw section 440, or any other suitable phase of the process. In other embodiments, the system may add a dye concentrate solution 415 during one or more (e.g., multiple) phases of the process described herein (e.g., the system may add some dye concentrate solution 415 to the polymer floc prior to passing the floc through the single screw section 410 extruder and some additional dye concentrate solution 415 after being extruded through the MRS section 420).

After the dye concentrate is added and extruded by the first single screw section 410, the resulting polymer melt (e.g., containing molten flake particles and dye concentrate) in various embodiments is then fed to the MRS extruder section 420, in which the extruder separates the melt stream into a plurality of different streams (e.g., 4 , 6, 8 or more streams) through multiple open cameras. Fig. 3 shows a detailed sectional view of an MRS section 420 in accordance with one particular embodiment. In particular embodiments, such as the embodiment shown in this drawing, the MRS section 420 separates the melt stream into eight different streams, which are then fed through eight satellite screws 425A-H. As can be understood from FIG. 2, in particular embodiments, these satellite augers are substantially parallel (e.g., parallel) to each other and to the main auger axis of the MRS machine 400.

In the MRS section 420, in various embodiments, the satellite screws 425A-H may, for example, rotate faster (eg, about four times faster) than in previous systems. As shown in FIG. 3, in specific embodiments (1) satellite screws 425A-H are located within a single screw drum 428 that is mounted to rotate about its central axis; and (2) the satellite screws 425A-H are configured to rotate in a direction opposite to that of the single screw drum 428. In various other embodiments, the satellite screws 425A-H and the single screw drum 428 rotate in the same direction. In particular embodiments, the satellite screws 425A-H are rotated by an internal gear. In addition, in various embodiments, the single screw drum 428 rotates approximately four times faster than each individual satellite screw 425A-H. In some embodiments, the satellite screws 425A-H rotate at substantially the same (eg, the same) speed.

In various embodiments, as can be understood from FIG. 4, satellite screws 425A-H are placed within respective extruder barrels, which may be approximately 30% open to the outer chamber of the MRS section 420, for example. (eg, makes more surface area of the molten polymer available to the open chamber than previous systems). In various embodiments, the MRS section 420 creates a melt surface area that is, for example, 20-30 times greater than the melt surface area created by a co-rotating twin screw extruder. In one particular embodiment, the MRS section 420 generates a melt surface area that is, for example, about 25 times the melt surface area generated by a co-rotating twin screw extruder.

In various embodiments, the MRS section 420 of the extruder is equipped with a vacuum pump 430 that is attached to the coupling portion 422 of the MRS section 420 so that the vacuum pump 430 communicates with the interior of the MRS section through a suitable opening 424 in the housing of the MRS section. In other embodiments, the MRS section 420 is equipped with multiple vacuum pumps. In particular embodiments, the vacuum pump 430 is configured to reduce the pressure

- 5 040205 inside the MRS section 420 to approximately 0.5-5 mbar. In particular embodiments, the vacuum pump 430 is configured to reduce the pressure in the MRS section 420 to less than about 1.5 mbar (eg, about 1 mbar or less). The low pressure vacuum created by the vacuum pump 430 in the MRS section 420 can remove, for example, (1) volatile organics formed in the molten polymer as it passes through the MRS section 420; and/or (2) at least a portion of any pore water that was present in the wet flake particles when they entered the MRS extruder 400. In various embodiments, low pressure vacuum removes substantially all (e.g., all) of the water and contaminants from the polymer flow.

In one particular example, the vacuum pump 430 includes three mechanical lobe vacuum pumps (eg, arranged in series) to reduce chamber pressure to a suitable level (eg, to approximately 1.0 mbar). In other embodiments, instead of the arrangement of three mechanical cam vacuum pumps discussed above, vacuum pump 430 includes a jet vacuum pump coupled to an MRS extruder. In various embodiments, this jet vacuum pump is configured to achieve a pressure of approximately 1 mbar within the MRS section 420 and approximately the same results as described above for the resulting intrinsic viscosity of the polymer melt. In various embodiments, the use of a jet vacuum pump can be advantageous because jet vacuum pumps are steam driven and therefore are inherently self-cleaning (e.g., self-cleaning), thereby reducing the need for maintenance compared to mechanical lobe pumps (which can, for example, , require repeated cleaning due to the resulting volatile substances condensing on the pump lobes). In one particular embodiment, the vacuum pump 430 is a jet vacuum pump manufactured by Arpuma GmbH, Bergheim, Germany.

In specific embodiments, after the molten polymer passes through the multi-stream MRS section 420, the molten polymer streams recombine and flow into the second single screw MRS section 440 of the extruder. In various embodiments, the implementation of the single stream of molten polymer then passes through the filtration system 450, which includes at least one filter. In one particular embodiment, the filtration system 450 includes two levels of filtration (eg, a 40 micron mesh filter followed by a 25 micron mesh filter). Although in various embodiments, water and volatile organic impurities are removed during the vacuum process discussed above, particulate contaminants such as, for example, aluminum particles, sand, dirt, and other contaminants may remain in the polymer melt. Thus, this filtration step may be beneficial in removing particulate contaminants (eg, particulate contaminants that have not been removed in the MRS section 420).

In specific embodiments, the viscosity sensor 460 (see FIG. 4) is used to determine the viscosity of the molten polymer stream after it has passed through the filtration system 450. In various embodiments, the viscosity sensor 460 measures the viscosity of the melt stream, for example, by measuring the pressure drop across the flow. through a well-known area. In particular embodiments, in response to measuring an intrinsic viscosity of a stream that is below a predetermined level (eg, below about 0.8 g/dL), the system may (1) exclude a low IV portion of the stream; and/or (2) reduce the pressure in the MRS section 420 in order to achieve a higher intrinsic viscosity of the polymer melt. In particular embodiments, pressure reduction in MRS section 420 is performed in a substantially automated manner (eg, automatically) using a viscosity sensor in a computerized feedback control loop with vacuum section 430.

In specific embodiments, the removal of water and contaminants from the polymer improves the intrinsic viscosity of the recycled PET polymer, allowing the polymer chains in the polymer to reconnect and increase the chain length. In particular embodiments, the recycled polymer melt, after passing through the MRS section 420 with the vacuum pump 430 attached, has an intrinsic viscosity of at least about 0.79 dl/g (eg, about 0.79-1.00 dl/g). In particular embodiments, passing through the low pressure MRS section 420 cleans the recycled polymer melt (eg, by removing contaminants and pore water) and renders the recycled polymer substantially structurally similar (eg, structurally similar) to the pure virgin PET polymer. In specific embodiments, the water removed by vacuum includes both the rinse water used to clean recycled PET bottles as described above, as well as unreacted water from melting the PET polymer in the single screw heater 410 (e.g., pore water). In particular embodiments, most of the water present in the polymer is wash water, but some percentage may be unreacted water.

Returning to FIG. 4, in particular embodiments, the color sensor 470 is used to determine the color of the resulting polymer melt. In various embodiments, the sensor

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The color 470 comprises one or more spectrographs configured to separate light passing through the polymer melt into a frequency spectrum to determine the color of the polymer melt. In other embodiments, the color sensor 470 includes one or more cameras or other suitable imaging devices configured to detect the color of the resulting polymer melt. In particular embodiments, in response to determining that the color of the polymer melt is different from the desired color (e.g., the polymer melt is lighter than desired, darker than desired, color is different from desired, etc.), the system may (1) exclude the portion of the stream with the wrong color and/or (2) adjust the amount of dye concentrate solution 415 added to the flake particles and/or polymer melt upstream in order to correct the color of the resulting polymer melt. In particular embodiments, the amount of dye concentrate solution 415 is controlled in a substantially automated manner (eg, automatically) using a color sensor 470 in a computerized feedback control loop.

In particular embodiments, the resulting polymer is a recycled PET polymer (e.g., derived from 100% post-consumer PET products such as PET bottles or containers) having a quality that is suitable for use in the manufacture of continuous PET filament carpet with using substantially only (eg, only) PET from recycled PET products.

Stage 3

Feeding purified PET resin to a spinning machine to be converted into carpet yarn.

In specific embodiments, after the recycled PET polymer has been extruded and purified using the extrusion process described above, the resulting molten recycled PET polymer is fed directly to a 500 BCF machine (or spinner) configured to convert the molten polymer into bulky continuous filament. For example, in various embodiments, the MRS outlet of extruder 400 is connected substantially directly (eg, directly) to the inlet of spinner 500 so that the molten polymer from the extruder is fed directly to the spinner 500. This process can be advantageous because the molten polymer in some embodiments may not need to be cooled and tableted after extrusion (as would be the case if the recycled polymer was blended with the original PET polymer). In particular embodiments, the lack of cooling and tableting of the processed molten polymer helps to avoid potential chain break in the polymer, which could lower the intrinsic viscosity of the polymer.

In particular embodiments, the spinning machine 500 extrudes the molten polymer through small holes in a spinneret to produce continuous carpet yarn filament from the polymer. In specific embodiments, the molten recycled PET polymer is cooled after exiting the die. The carpet yarn is then picked up by rollers and eventually converted into continuous filaments which are used to make carpets. In various embodiments, the carpet yarn produced by the spinner 500 may have a tear strength of about 3-9 g-s/denier. In specific embodiments, the resulting carpet yarn has a tear resistance of at least about 3 g-s/denier.

In specific embodiments, the spinning machine 500 used in the process described above is a Sytec One spinning machine manufactured by Oerlika Neumag, Neumünster, Germany. The Sytec One can be specially adapted for difficult-to-process fibers such as nylon or solution-dyed fibers where continuous filaments are prone to breakage during processing. In various embodiments, the Sytec One machine keeps the filaments as straight as possible after the spinneret, uses only one filament, and is designed to be able to quickly start a filament when it breaks.

Although the example described above describes the use of a Sytec One spinning machine to make a continuous filament of carpet yarn from a polymer, it should be understood that any other suitable spinning machine may be used. Such spinning machines may include, for example, any suitable single or triple thread spinning machine manufactured by Oerlika Neumag, Neumünster, Germany, or any other company.

In various embodiments, the improved strength of the recycled PET polymer obtained using the process described above allows it to be passed through the spinner 500 at higher speeds than would be possible with pure virgin PET polymer. This may allow higher processing speeds than with virgin PET polymer.

Sample Process Summary

Fig. 5 shows a high-level block diagram of various embodiments of the above-described method for manufacturing bulky continuous filament. As shown in this flowchart, the process begins at step 602 where recycled PET bottles are ground into a group of flake particles.

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Next, in step 604, the group of flocs is washed to remove contaminants from the respective outer surfaces of the flocs. Then, in step 606, the group of flocs is scanned (eg, using one or more of the methods discussed above) to identify impurities, including contaminated flocs. These impurities and contaminated flakes are then removed from the flocculation group.

Then, in step 608, the flake group is passed through the MRS extruder while maintaining the pressure within the MRS portion of the extruder below about 1.5 mbar. In step 610, the resulting polymer melt is passed through at least one filter with a mesh size of less than about 50 microns. Finally, in step 612, the recycled polymer is spun into a bulky continuous carpet filament that can be used in the manufacture of carpets. The method ends at step 614.

Alternative Embodiments

In specific embodiments, the system may contain alternative components or perform alternative processes in order to produce a substantially continuous BCF from 100% recycled PET or other recycled polymer. Exemplary alternatives are discussed below.

He-MRS extrusion system

In particular embodiments, the process may use a polymer stream extrusion system other than the MRS extruder described above. An alternative extrusion system may include, for example, a twin screw extruder, a multi-screw extruder, a planetary extruder, or any other suitable extrusion system. In one particular embodiment, the process may include a plurality of any combination of any suitable conical screw extruders (eg, four twin screw extruders, three multi screw extruders, etc.).

Getting carpet yarn from 100% recycled carpet

In specific embodiments, the process described above can be adapted to process old carpets (or any other suitable used product) to make new carpet yarn containing 100% recycled carpets. In such embodiments, the process begins by grinding and washing used carpets instead of used PET bottles. In various embodiments in which old carpets are converted to new carpet yarn containing 100% recycled carpets, the process may include additional steps to remove additional materials or impurities that may be present in used carpets that may not be present in used PET bottles ( e.g. carpet backing, adhesive, etc.).

Other sources of recycled PET

In various embodiments, the process described above is adapted to process recycled PET from any suitable source (eg, sources other than used bottles or carpets) to produce new carpet yarn containing 100% recycled PET.

Use of a crystallizer as part of the BCF process

In various embodiments, the process for making recycled BCF may further include a crystallization step that uses one or more PET crystallizers. In particular embodiments, the system is configured to perform a crystallization step on the milled flake particles prior to passing the flake particles through one or more extruders (eg, single screw extruder, MRS extruder, etc.). In specific embodiments, the PET mold comprises a housing, a bin screw (eg, screw conveyor) located at least partially within the housing, an agitator, one or more heating elements, and one or more fans.

Hopper auger

In particular embodiments, the hopper auger comprises any suitable screw conveyor (eg, such as an Archimedes spiral) for transferring liquid or granular materials (eg, such as PET flakes). In various embodiments, the hopper auger comprises a substantially cylindrical shaft and a helical auger blade located along at least a portion of that cylindrical shaft. In particular embodiments, the substantially cylindrical shaft is configured to rotate the screw blade causing the hopper screw to move material (eg, PET flakes) along the cylindrical shaft into the mold body. In other embodiments, the implementation of the auger hopper contains any other suitable screw conveyor, such as, for example, a shaftless spiral. In those embodiments where the hopper auger comprises a shaftless helix, the shaftless helix may be substantially fixed at one end and loose at the other end and configured to be driven at the fixed end. In various embodiments, the hopper auger is located at least partially within the mold housing.

In various embodiments, the hopper screw is configured to feed PET flakes into the mold. In various embodiments, the PET mold is configured to feed PET flakes into the mold using a hopper screw at a relatively slow speed.

One or more heating elements

In various embodiments, the mold contains one or more heating elements to raise the temperature within the mold. In particular embodiments, the one or more heating elements comprise one or more electric heating elements, one or more gas heating elements, or any other suitable heating elements. In some embodiments, one or more heating elements may be operated essentially electrically. In various embodiments, one or more heating elements comprise one or more infrared heating elements. In other embodiments, one or more heating elements may use natural gas such as, for example, propane. In specific embodiments, one or more heating elements are configured to raise the temperature within the mold to about 100-180°F. In other embodiments, one or more heating elements are configured to raise the temperature within the mold to about 100-180°C. In some embodiments, one or more heating elements are configured to maintain a temperature within the mold that is substantially approximately the maximum crystallization temperature of the PET. In specific embodiments, the implementation of the maximum temperature of crystallization of PET is approximately 140-230°C.

One or more fans

In various embodiments, the mold further comprises one or more fans configured to blow air over the flakes as they pass through the mold. In particular embodiments, the one or more fans comprise any suitable fans to move air substantially across the surface area of the flocs as they pass through the mold. For example, in some embodiments, one or more fans comprise one or more suitable blades or other suitable mechanisms for moving air. In various embodiments, one or more fans are configured to blow through air that has been at least partially heated by one or more heating elements. In particular embodiments, one or more fans are configured to blow air having a temperature of at least about 140°F. In other specific embodiments, one or more fans are configured to blow air having a temperature of at least about 140°C. In other embodiments, one or more fans are configured to maintain the temperature in the mold in the range of approximately 140-180°F. In some embodiments, one or more fans are configured to blow hot air from the bottom of the mold and draw air from the top of the mold.

Mixer

In various embodiments, the crystallizer comprises an agitator that contains any suitable device for mixing the PET flake particles as they pass through the crystallizer. In various embodiments, the agitator may be driven by, for example, any suitable geared motor. In one particular embodiment, the agitator comprises a suitable rod or other suitable mechanism positioned to rotate or otherwise agitate the PET flakes as they pass through the mold. In other embodiments, the agitator may comprise any suitable tilter, which may, for example, comprise a drum mounted to be rotated by a geared motor such that the PET flakes are at least partially agitated and/or agitated when they are in inside this drum. In other embodiments, the agitator comprises one or more screws and/or screw conveyors configured to rotate and mix the PET flakes. In specific embodiments, the agitator comprises a hopper auger.

As can be understood from this disclosure, the agitator is configured to stir or mix the PET flake particles as one or more fans blow air heated by the one or more heating elements through the PET flake particles. In particular embodiments, the agitator is configured to at least partially reduce agglomeration (eg, agglomeration or clumping of the flocculated particles) while the flocculated particles are at least partially crystallized in the mold.

In particular embodiments, the crystallizer at least partially dries the surface of the PET flake particles. In various embodiments, the PET mold is configured to reduce the moisture content of the PET flakes to about 50 ppm. In other embodiments, the PET mold is configured to reduce the moisture content of the PET flakes to about 30-50 ppm.

- 9 040205

In various embodiments, the use of drier flake particles may allow the system to pass the flake particles through the MRS extruder more slowly, which may provide higher pressure within the MRS extruder during extrusion (e.g., may allow the system to maintain a higher pressure within the MRS extruder instead of a very low pressure). ). In various embodiments of the process, the pressure control system may be configured to maintain the pressure within the MRS of the extruder at approximately 025 mbar. In particular embodiments, such as those in which PET flakes are passed through a mold prior to being extruded in an MRS extruder, the pressure control system may be configured to maintain a pressure within the MRS extruder of about 0-18 mbar. In other embodiments, the pressure control system may be configured to maintain the pressure within the MRS of the extruder at approximately 0-12 mbar. In other embodiments, the pressure control system may be configured to maintain the pressure within the MRS of the extruder at approximately 0-8 mbar. In other embodiments, the pressure control system may be configured to maintain the pressure within the MRS of the extruder at approximately 510 mbar. In particular embodiments, the pressure control system may be configured to maintain the pressure within the MRS of the extruder at about 5 mbar, about 6 mbar, about 7 mbar, about 8 mbar, about 9 mbar, or any suitable pressure in the range of about 0-25 mbar. In particular embodiments, the crystallizer causes the flake particles to at least partially decrease in size, which may, for example, reduce the agglomeration potential of the flocculate particles. In particular embodiments, the crystallizer may specifically detack large flake particles, which may, for example, include flake particles containing ground PET bottle portions that may be thicker than other PET bottle portions (e.g., flake particles). , obtained from the screw part of a PET bottle, on which the cap is usually screwed).

Use of recyclables in the process compared to bail bottles

In various embodiments, the system is configured to use different qualities of recycled PET in the process described above. For example, in various embodiments, the system is configured to produce bulk continuous carpet fiber from PET obtained from recycled bottles (e.g., PET bottles that were collected as part of a general recycling program or other source of recyclables) as well as from collateral. bottles (for example, bottles returned under the deposit program). In various embodiments, recycled waste bottles may require more processing in order to produce a bulky continuous filament because PET waste bottles may be mixed or otherwise include contaminants such as, for example, other recyclable materials (e.g. , paper, other plastics, etc.), garbage and other non-PET bottles due to imperfect sorting of recyclables or for any other reason. PET bail bottles can include PET bottles with fewer unwanted contaminants, in part because PET bail bottles can be collected separately from other recyclable or disposable products.

In various embodiments, PET waste bottles collected at particular times of the year may include more impurities and other contaminants than at other times of the year. For example, PET trash bottles collected during the summer months may contain a higher percentage of clean PET bottles (eg, water bottles), due at least in part to additional water consumption during the summer months.

In various embodiments, the system described above may be configured to adjust specific process components based at least in part on the recycled PET source used to make the bulk continuous carpet filament. For example, since PET bail bottles include fewer contaminants to be removed during the initial cleaning and sorting phases, the pressure control system can be configured to maintain a pressure within the MRS extruder that is higher than that required when processing PET flake particles. obtained from waste sources of recyclable materials. In one particular embodiment, the pressure control system may be configured to maintain the pressure within the MRS extruder in the range of approximately 0-12 mbar as flakes obtained from PET bail bottles pass through the MRS extruder. In other embodiments, the pressure control system may be configured to maintain the pressure within the MRS of the extruder in such cases at about 5-10 mbar.

In various embodiments, the system is configured to determine the appropriate pressure within the MRS extruder based at least in part on a source of recycled PET. In other embodiments, the system is configured to omit one or more of

- 10 040205 the steps described above, or include one or more additional steps based at least in part on a recycled PET source.

Use of dyed PET and color additives

In various embodiments, systems for making the recycled bulky continuous filament described above may use dyed (colored) used PET bottles (or other containers) in addition to the clear PET bottles described herein. For example, in particular embodiments, the system may use blue, green, yellow, or any other suitable colored bottles in the production of recycled BCF (eg, instead of removing substantially all of the colored PET from the recycled PET early in the process). In some embodiments, the process includes one or more additional steps that include, for example, adding one or more color additives (e.g., one or more dye concentrate solutions) that can, for example, dilute the coloring of the resulting processed fiber caused by using dyed PET in the recycling process.

Proportion of colored flocculent particles

In various embodiments, the PET bottles used in the production of recycled BCF may include a specific percentage of clean and colored bottles (eg, by volume, by weight, etc.). For example, in specific embodiments, recycled BCF can be produced using at least about 80% (eg, 80%) colorless bottles and no more than about 20% (eg, 20%) color bottles. In particular embodiments, the colored bottles that the system uses along with clean bottles to make recycled BCF may only include recycled bottles of one specific color (eg, green bottles only, blue bottles only, yellow bottles only, etc.). In particular embodiments, the system may be configured to use bottles of one particular shade of one particular color. For example, in various embodiments, the system may be configured to use lighter blue bottles (eg, bottles of one particular light shade of blue) but not use darker blue bottles. In other embodiments, the system may be configured to use any suitable colored bottles (eg, from other recycled PET sources) in any suitable ratio.

In various embodiments, the process may use from about 6.5% (eg, 6.5%) to about 9% (eg, 9%) of colored PET with a balance of colorless PET. In other embodiments, the process may use approximately 6-10% dyed PET. In other embodiments, the implementation of the process can use up to about 10% colored PET with the remainder of the essentially colorless PET. In other embodiments, the process may use approximately 1-10% dyed PET with the remainder being essentially colorless PET. In other embodiments, the process may use any other suitable ratio of dyed recycled PET to colorless recycled PET.

Use of dyed flakes based on desired carpet color

In various embodiments, the number of colored PET bottles used in the process may be based, at least in part, on the color of the carpet that will ultimately be made from the recycled BCF produced by the process. For example, for darker carpets, the recycled BCF used in their manufacture can be produced using a higher percentage of dyed PET bottles. In various embodiments, the use of a higher percentage of dyed PET bottles may result in darker recycled continuous filament BCF, which may, for example, be unsuitable for making specific dyed carpets (eg, lighter carpets). Carpets that will eventually be dyed darker colors (or solution dyed darker) may be more suitable for manufacture using recycled BCF made at least in part from dyed PET bottles. For example, the production of recycled BCF for use in brown carpets may use at least a specific amount of yellow PET bottles in the recycling process (eg, 20% yellow and 80% colorless, or any other suitable ratio).

In one particular example, the system may use 2% or less colored PET bottles in a relatively light color BCF manufacturing process. This can help reduce or eliminate the need to use a color correction concentrate (discussed in more detail below) in order to achieve the desired light color BCF.

In some situations, it may be advantageous to use a high percentage of colored PET bottles as this may reduce the amount of dye solution needed to achieve the desired color. For example, it may be advantageous to use more than about 80%, about more than 90%, about more than 95%, or about 100% dyed PET in the process of making some dark (or other dyed) recycled BCF. For example, in various embodiments, it may be advantageous to use more than 95% dyed PET in the production of dark green recycled BCF as this may reduce the amount of dye solution needed to achieve the desired dark green color.

In various embodiments, it may be acceptable to use percentages of dyed PET that are common in purchased lots of trash bottles. Such percentages are typically about 6.5-9.5% of dyed PET. In specific situations where such ranges are acceptable, the system may not sort dyed and undyed PET. Instead, dyed and undyed PET are processed and used together. However, non-PET polymers can be separated from the mixture and excluded as described above.

Using Corrective Dye Concentrate with Colored PET

In particular embodiments, the system is configured to use any suitable solution dyeing technique to at least partially correct (e.g., substantially correct) any coloration of the BCF continuous filament produced by the above process using dyed recycled PET. . In various embodiments, the system is configured to add a dye concentrate to the polymer flake before extrusion (or to the polymer melt during or after extrusion) in order to at least partially correct the color of the resulting continuous filament through the use of dyed recycled PET. In specific embodiments, the dye concentrate may include any suitable dye concentrate that may, for example, produce one particular color of the polymer fiber (eg, bulky continuous filament) after extrusion. In various embodiments, adding a dye concentrate to the flake prior to extrusion can result in a polymeric continuous filament that is at least partially impregnated (eg impregnated) with a color pigment. In various embodiments, color pigment impregnation can correct any coloration of the resulting fiber through the use of dyed recycled PET during the extrusion process. In particular embodiments, a carpet made from a solution-dyed continuous filament can be highly resistant to fading from sunlight, ozone, harsh cleaning agents such as bleach, or other factors.

In various embodiments, the dye concentrate includes any suitable dye dispersion in a compatible carrier. In some embodiments, colorant concentrates are designed to, when added to a natural resin (eg, PET) in a predetermined proportion, color the resin substantially uniformly (eg, uniformly) to match the desired color. In some embodiments, the implementation of the dye may contain mixtures of pigments in the resin, which may, for example, include particles of insoluble colored material. In other embodiments, the colorant concentrates may include one or more polymer-soluble colorants that are suitable alone or in combination with one or more pigments.

In particular embodiments, the system is configured to add from about 2 wt.% (eg, 2 wt.%) to about 3 wt.% (eg, 3 wt.%) of the dye concentrate to the polymer flake. In other embodiments, the system is configured to add from about 0% (eg, 0%) to about 3% (eg, 3%) of dye concentrate by weight or volume. In other embodiments, the system is configured to add up to about 6% by weight (eg, 6% by weight) of dye concentrate to the polymer flake prior to extrusion. In some embodiments, the implementation of the system is configured to add from about 1 wt.% (for example, 1 wt.%) to about 3 wt.% (for example, 3 wt.%) of the dye concentrate to the polymer flake. In other embodiments, the system is configured to add any suitable amount of dye concentrate to the polymer flake in order to achieve a particular color of the molten polymer (and ultimately the polymer fiber) after extrusion.

Fig. 4 depicts an embodiment in which the dye concentrate is added to the polymer flake (eg, a mixture of colored and colorless PET flake particles) before the flake particles are fed into the first single screw extruder section 410. It should be understood that in other embodiments, the dye concentrate may be added during any other suitable phase of the process described herein. For example, in various embodiments, such as any of the examples discussed above, the system may be configured to add colorant concentrate after the polymer flake is extruded by the first single screw extruder section 410, but before the resulting polymer melt is fed through the MRS extruder section 420 discussed herein. . In other embodiments, the system may add the dye concentrate after the flakes have passed through the MRS section 420 of the extruder, before the polymer melt passes through the second single screw section 440 discussed herein. In other embodiments, the system may add the dye concentrate while the flakes and/or polymer melt are being extruded in the first single screw section 410 of the extruder, the MRS section 420, the second single screw section 440, or any other suitable phase of the process. In other embodiments, the system may add colorant concentrate during one or more (e.g., multiple) phases of the process described herein (e.g., the system may add some colorant concentrate to the polymer flake before the flake particles pass through single screw extruder section 410 and some additional the amount of dye concentrate after being extruded through the MRS section 420).

In various embodiments, the use of a dye concentrate at least partially masks any coloration of the resulting bulky continuous filament produced using the aforementioned dyed recycled PET process. In such embodiments, the resulting bulky continuous filament may have a color that is substantially similar to the color of bulky continuous filament produced using only substantially colorless (eg, colorless) recycled PET and dye concentrate.

Essentially automated solution dyeing

In various embodiments, the system is configured to substantially automatically control the amount of dye concentrate added to the polymer flake and/or polymer melt in order to produce the desired color of the BCF continuous filament. In various other embodiments, the system is configured to substantially automatically determine the amount of dye concentrate to be added to the dyed PET in order to sufficiently offset the color of the dyed PET. In such embodiments, the system may, for example, use a suitable feedback loop that includes (1) determining the color of the bulky continuous filament produced by the process; (2) determining if the color is acceptable (eg, if it is a specific target color and/or a color corresponding to one or more predefined color targets); (3) substantially automatically adjusting the amount of dye concentrate added to the upstream dyed PET based at least in part on a determined color (if it is acceptable according to one or more predefined color guides). In particular embodiments, the system is configured to automatically adjust the amount of dye concentrate added to dyed (colored) PET to ensure that it is sufficient to ensure that the resulting dyed PET satisfies one or more predetermined color targets.

Dyeing without a solution to mask the dyed PET in the resulting continuous filament

In various embodiments, the process may use any suitable dyeing technique, other than the solution dyeing technique described above, in order to at least partially mask the coloration of the continuous filament produced using the recycled BCF process described herein using dyed recycled PET. For example, in various embodiments, the process may use any suitable skein dyeing technique, any suitable continuous dyeing technique, any suitable polychromatic dyeing technique, any suitable vat dyeing technique, or any other suitable dyeing technique or suitable combination of dyeing techniques.

Blending PTT with PET to increase dyeability

In various embodiments, such as embodiments in which the process includes adding one or more dye solutions to recycled PET, which includes dyed PET, the process may include adding polytrimethylene terephthalate (PTT) (or any other suitable additive) to PET before extrusion, during extrusion, together with the color concentrate, separately from the color concentrate, or at any other appropriate time. In various embodiments, this blend of PTT (or other additive) and PET may have improved colorability compared to PET that has not been blended with PTT. In particular embodiments, the process includes using from about 5% (eg 5%) to about 14% (eg 14%) PTT (or other additive) by weight or volume in the mixture. In other embodiments, the process includes using from about 6% (eg, 6%) to about 10% (eg, 10%) of PTT (or other additive) by weight or volume in the mixture. In other embodiments, the process includes adding up to about 14% (eg, 14%) PTT (or other additive) by volume or weight (eg, from about 0% to about 14% PTT). In various embodiments, the addition of PTT (or other additive) to PET can reduce the cost of dyeing the resulting fiber.

In various embodiments, the implementation of the process may use the primary PTT. In other embodiments, the process may use a secondary PTT. In some embodiments, PTT can be recycled from any suitable source such as, for example, used PTT carpets, used food containers, and/or other suitable PTT products. In various embodiments, the PTT may include secondary PTT extracted (eg, recycled) using the process described herein.

In various embodiments, the above process may be suitable for processing PTT for use in blending recycled PTT (or other suitable additive) with PET in order to improve the colorability of PET due to the similar chemical composition of PTT and PET. The resulting combination may have higher durability and resiliency than conventional polyesters (eg PET). In particular embodiments, PTT is particularly useful in the manufacture of carpets due to PTT's stain resistance. PTT carpets can, for example, at least generally retain their original appearance by simply vacuuming and washing with hot water. This can lead, for example, to an increase in the service life of a carpet made using PTT. In particular embodiments, the PTT is substantially hydrophobic, which may contribute to the stain resistance of PTT carpets. In various embodiments, PTT carpets are also substantially soft (eg, to the touch). The softness of PTT carpets may be due, for example, to the absence of topical stain protection chemicals due to PTT's inherent hydrophobic tendencies. It should be understood, based on the above discussion, that any suitable additive can be used instead of or in addition to PTT in the examples discussed above.

Adding Color Enhancers

In various embodiments, such as those in which the process includes adding one or more color enhancers to recycled PET that includes dyed PET, the process may include adding DEG (or any other suitable color enhancer) to the PET. before extrusion, during extrusion, together with the color concentrate, separately from the color concentrate, or at any other appropriate time. In various embodiments, the blend of color enhancer and PET may have improved colorability compared to PET that has not been blended with the color enhancer. In particular embodiments, the process includes using from about 0% (eg, 0%) to about 5% (eg, 5%) of a color enhancer (eg, DEG) by weight or volume in the mixture. In some embodiments, the process includes using from about 1% (eg, 1%) to about 2% (eg, 2%) of a color enhancer (eg, DEG) by weight or volume in the mixture.

Conclusion

Many modifications and other embodiments of the present invention can be made by a person skilled in the art, based on the advantages of the above description, together with the accompanying drawings. For example, although the vacuum system discussed above is described as being capable of maintaining the pressure in the open chambers of the MRS extruder at levels of approximately 1 mbar, in other embodiments, the vacuum system may be configured to maintain the pressure in the open chambers of the MRS extruder at levels greater than or less than 1 mbar. For example, the vacuum system may be configured to maintain this pressure in the range of about 0.5 mbar to about 12 mbar.

Similarly, while the various system embodiments described above may be configured to produce continuous carpet filament substantially from recycled PET only (so that the resulting continuous carpet filament contains, consists of, and/or consists essentially of recycled PET), in other embodiments, the system may be configured to produce continuous carpet filament from a combination of recycled PET and virgin PET. The resulting continuous carpet filament may, for example, contain, consist of, and/or consist essentially of about 80-100% recycled PET and about 0-20% virgin PET.

In addition, it should be understood that when polymer proportions are discussed herein (e.g., as percentages), such as the ratio of dyed recycled PET to colorless recycled PET, dye concentrate and polymer flake, etc., these percentages may include itself volume percentages, mass percentages, weight percentages, or any other suitable relative measure.

Furthermore, while various embodiments have been discussed above in relation to making continuous carpet filament from PET, similar techniques can be used to making continuous carpet filament from other polymers. Likewise, while various embodiments have been discussed above in relation to making continuous carpet filament from PET, similar techniques can be used to make other products from PET or from other polymers.

In addition, it should be understood that various embodiments may not contain any of the steps described above or may contain additional steps.

The present invention further relates to several preferred embodiments as defined in the paragraphs below.

1. A method of manufacturing a bulk continuous elemental carpet fiber, comprising (A) providing a multi-screw extruder, which contains (i) the first satellite screw extruder containing the first satellite screw, which is mounted for rotation around the Central axis of the first satellite screw;

(ii) a second satellite screw extruder comprising a second satellite screw that is rotatably mounted about a central axis of the second satellite screw; and (iii) a pressure control system that is configured to maintain pressure within the first and second satellite screw extruders in the range of about 0 mbar to about 5 mbar;

(B) using a pressure control system to reduce the pressure within the first and second satellite screw extruders to a range of about 0 mbar to about 5 mbar;

(C) providing a plurality of polymer flake particles containing from about 6% to about 10% colored recycled polyethylene terephthalate (PET) flake particles and the remainder as substantially colorless recycled PET flake particles;

(D) providing one or more dye concentrates;

(E) adding said one or more color concentrates to said plurality of polymer flakes such that the resulting mixture contains from about 0% to about 3% by weight of said one or more color concentrates;

(F) while maintaining pressure within the first and second satellite screw extruders in the range of about 0 mbar to about 5 mbar, passing said plurality of polymer flakes and said one or more dye concentrates through a multi-screw extruder to form a polymer melt such that ( 1) the first part of the polymer melt passed through the first satellite screw extruder and (2) the second part of the polymer melt passed through the second satellite screw extruder;

(G) after the step of passing the polymer melt through a multi-screw extruder, spinning the recycled polymer into bulk continuous carpet filament.

2. The method of claim 1, wherein the dyed recycled PET flake consists essentially of dyed PET flake obtained from recycled PET bottles.

3. The method of claim 2, wherein the dyed recycled PET flake contains one or more colors selected from the group consisting of

i) yellow flaky particles of PET;

ii) blue PET flakes; and iii) green PET flakes.

4. The method according to claim 1, further comprising providing a color sensor configured to determine the color of the polymer melt;

substantially automatically adjusting the amount of said one or more colorant concentrates added to said plurality of polymer flakes based at least in part on the determined color of the polymer melt.

5. The method according to claim 4, in which the mentioned set of polymer flake particles contains approximately 6-10 wt.% colored recycled PET flake particles;

up to about 6 wt.% polytrimethylene terephthalate;

and the remainder as substantially colorless recycled PET flakes.

6. The method according to claim 5, in which the mentioned set of polymer flake particles contains approximately 7-9 wt.% colored recycled PET flake particles;

about 5-6 wt.% PTT;

and the remainder as substantially colorless recycled PET flakes.

7. The method of claim 1, wherein said one or more dye concentrates at least partially correct the color of bulk continuous carpet filament from dyed recycled PET flake.

In light of the foregoing, it should be understood that the present invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are to be included within the scope of the appended claims. Although specific terms are used in this document, they are used in a general and descriptive sense only and not for purposes of limitation.

Claims (5)

CLAIM 1. A method for manufacturing bulk continuous elementary carpet fiber, comprising: (A) providing a multi-screw extruder that contains: (i) a first satellite screw extruder comprising a first satellite screw that is rotatably mounted about a central axis of the first satellite screw; (ii) a second satellite screw extruder comprising a second satellite screw that is rotatably mounted about a central axis of the second satellite screw; and (iii) a pressure control system that is configured to maintain pressure within the first and second satellite screw extruders in the range of 0 to 5 mbar; (B) using a pressure control system to reduce the pressure inside the first and second satellite screw extruders to a range of 0 to 5 mbar; (C) providing a plurality of polymer flake particles containing 6% to 10% colored flake particles from recycled polyethylene terephthalate (PET) and the remainder as substantially colorless flake particles from recycled PET; (D) providing one or more dye concentrates; (E) adding said one or more color concentrates to said plurality of polymer flocculent particles such that the resulting mixture contains 0 to 3% by weight of said one or more color concentrates; (F) while maintaining pressure within the first and second satellite screw extruders in the range of 0 to 5 mbar, passing said plurality of polymer flakes and said one or more dye concentrates through a multi-screw extruder in order to form a polymer melt such that (1) the first a portion of the polymer melt passed through the first satellite screw extruder; and (2) a second portion of the polymer melt passed through the second satellite screw extruder; (G) after the step of passing the polymer melt through a multi-screw extruder, spinning the recycled polymer into bulk continuous carpet filament. 2. The method of claim 1, wherein the dyed recycled PET flake consists essentially of dyed PET flake obtained from recycled PET bottles. 3. The method of claim 2, wherein the dyed recycled PET flake contains one or more colors selected from the group consisting of: i) yellow flaky particles of PET; ii) blue PET flakes; iii) green flaky PET particles. 4. The method according to claim 1, further comprising providing a color sensor configured to determine the color of the polymer melt; substantially automatically adjusting the amount of said one or more colorant concentrates added to said plurality of polymer flakes based at least in part on the determined color of the polymer melt. 5. The method of claim 1, wherein said one or more dye concentrates at least partially correct the color of bulk continuous carpet filament from dyed recycled PET flake.