This invention involves a new and better solution to the problems associated with the premature softening of PLA filaments in the additive manufacturing of three dimensional articles. It is based upon the finding that poly(lactic acid) filaments with high crystallinity offer much better resistance to heat-induced softening. The crystalline poly(lactic acid) filament of this invention can accordingly be used in the additive manufacturing of three dimensional articles without encountering the problems associated with premature softening, such as poor quality and printer jamming. The crystalline poly(lactic acid) filaments of this invention can also be used in additive manufacturing of three dimensional articles without compromising the quality of the ultimate product, reducing printing speed, increasing cost, or leading to increased printer complexity. This invention more specifically discloses a filament for use in three-dimensional printing which is comprised of crystallized poly(lactic acid), wherein said filament has a diameter which is within the range of 1.65 mm to 1.85 mm.

Provided is a polymeric material having a micro-nano composite structure, a device including the same, and a method of manufacturing the polymeric material. The polymeric material includes a polymer fiber or film, wherein the polymer fiber or film has, on a surface thereof, a micro-nano composite structure including a microstructure containing concavo-convex grooves having a microscale semi-cylindrical shape () and a nanopattern containing nanoscale protrusions formed on a surface of the microstructure. The polymeric material has excellent absorbency and hydrophilic or super-hydrophilic surface properties, and also has oleophobic or super-oleophilic properties in water, and thus may be effectively applied to fields such as oil-water separation, purification, and filters. The polymeric material may be readily manufactured through an environmentally friendly, large-area atmospheric pressure plasma process.

The present invention provides a system and method for quickly removing and installing a filament tube and nozzle in an FFF extrusion system. The system utilizes a primary manifold that includes a cooling block, a heating block and a quick-change mechanism. This primary manifold is adapted to mate a filament tube/nozzle assembly. The quick-change mechanism, which in a particular embodiment utilizes a recessed biased-bearing arrangement, enables the filament/nozzle assembly to be removed and inserted without the use of any tools, and without causing any significant downtime for the FFF extrusion system. Once removed, the filament tube/nozzle assembly can be refurbished by a technician, trained so as not to over torque the tube/nozzle threaded interface. This refurbishment (typically consisting of a cleaning and the installation of a new nozzle) could be accomplished off-line, without any impact on the continued use of FFF extrusion system.

A device (1) for the extrusion of filaments (2) comprising a plurality of extrusion capillaries (3) arranged in at least two consecutive rows and having extrusion openings (4) for extruding a spinning solution, whereby the filaments (2) are formed, and a plurality of components (7, 8, 10) for the generation of a gas stream for producing a gas stream oriented essentially in the direction of the extrusion of the filaments (2) at least in the area of the extrusion openings (4), wherein the extrusion capillaries (3) are arranged in extrusion columns (6) which protrude from a base plate (5) and are formed in one piece with said base plate (5).

There is provided a method of making a hollow fiber. The method includes mixing, in a first solvent, a plurality of nanostructures, one or more first polymers, and a fugitive polymer which is dissociable from the nanostructures and the one or more first polymers, to form an inner-volume portion mixture. The method further includes mixing, in a second solvent, one or more second polymers to form an outer-volume portion mixture, and spinning the inner-volume portion mixture and the outer-volume portion mixture to form a precursor fiber. The method further includes heating the precursor fiber to oxidize the precursor fiber and to change a molecular-bond structure of the precursor fiber, and during heating, extracting the fugitive polymer from the inner-volume portion mixture. The method further includes obtaining the hollow fiber with the inner-volume portion having the nanostructures and the first polymers, and with the outer-volume portion having the second polymers.

A method of manufacturing a plurality of colors of bulked continuous carpet filament from a single multi-screw extruder which, in various embodiments, comprises: (A) passing PET through an extruder that melts the PET and purifies the resulting PET polymer melt; (B) splitting the extruded polymer melt into a plurality of melt streams and adding a colorant to each of the plurality of melt streams; (C) using one or more static mixers (e.g., thirty six static mixers) to substantially uniformly mix (e.g., homogeneously mix) each of the plurality of melt streams with its respective added colorant; and (D) feed each of the uniformly mixed and colored plurality of melt streams into a respective spinning machines that turns the polymer into filament for use in manufacturing carpet, rugs, and other products.

A method of manufacturing bulked continuous carpet filament, in various embodiments, comprises: (A) providing an expanded surface area extruder; (B) providing a spinning machine having an inlet that is operatively coupled to an expanded surface area extruder outlet; (C) using a pressure regulation system to reduce the pressure within the expanded surface area extruder; (D) passing a plurality of flakes comprising recycled PET through the expanded surface area extruder to at least partially melt the plurality of flakes to form a polymer melt; and (E) substantially immediately after passing the plurality of flakes through the expanded surface area extruder, using the spinning machine to form the polymer melt into bulked continuous carpet filament. In some embodiments, the method may include passing the plurality of flakes comprising recycled PET through a PET crystallizer prior to extrusion.

A method of manufacturing bulked continuous carpet filament which, in various embodiments, comprises: (A) washing a plurality of flakes of recycled PET; (B) providing a PET crystallizer; (C) after the step of washing the plurality of flakes, passing the plurality of flakes of recycled PET through the PET crystallizer; (D) at least partially melting the plurality of flakes into a polymer melt; (E) providing a multi-rotating screw (MRS) extruder having an MRS section; and a vacuum pump in communication with the MRS section; (F) using the vacuum pump to reduce a pressure within the MRS Section; (G) after the step of passing the plurality of flakes through the PET crystallizer, passing the polymer melt through the MRS Section; and (H) after the step of passing the polymer melt through the MRS extruder, forming the polymer melt into bulked continuous carpet filament.

Resorbable multifilament yarns and monofilament fibers including poly-4-hydroxybutyrate and copolymers thereof with high tenacity or high tensile strength have been developed. The yarns and fibers are produced by cold drawing the multifilament yarns and monofilament fibers before hot drawing the yarns and fibers under tension at temperatures above the melt temperature of the polymer or copolymer. These yarns and fibers have prolonged strength retention in vivo making them suitable for soft tissue repairs where high strength and strength retention is required. The multifilament yarns have tenacities higher than 8.1 grams per denier, and in vivo, retain at least 65% of their initial strength at 2 weeks. The monofilament fibers retain at least 50% of their initial strength at 4 weeks in vivo. The monofilament fibers have tensile strengths higher than 500 MPa. These yarns and fibers may be used to make various medical devices for various applications.

In particular embodiments, a process for producing bulked continuous carpet filament from recycled polymer utilizes two vacuum pumps (140A, 140B) in combination with a single extruder (100). In various embodiments, the dual vacuum arrangement (e.g., at least two vacuum pumps (140A, 140B)) operably coupled to the single extruder (e.g., MRS extruder (100)) may be configured to remove one or more impurities from recycled polymer as the recycled polymer passes through the extruder.