Polymer filaments for additive manufacturing with reduced emissions

Abstract

To provide polymer filaments compatible with fused filament fabrication, capable of reducing volatile organic compound (VOC) emissions while 3D printing.SOLUTION: Polymer filaments comprise a thermoplastic polymer and a bio-based additive; the bio-based additive is admixed with the thermoplastic polymer in an effective amount to decrease total volatile organic compound (TVOC) emissions under additive manufacturing conditions, as determined by gas chromatography and measured relative to the thermoplastic polymer alone, by at least about 10% on a weight basis. Methods for forming a polymer filament compatible with fused filament fabrication may comprise: forming a melt blend comprising a thermoplastic polymer and a bio-based additive; and extruding the melt blend and cooling to form a polymer filament comprising the bio-based additive admixed with the thermoplastic polymer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to additive manufacturing, and more specifically to polymer filaments compatible with fused filament manufacturing that reduce volatile organic compound (VOC) emissions during printing. [Background technology]

[0002] Additive manufacturing, also known as three-dimensional (3D) printing, is a rapidly growing field of techniques. While additive manufacturing has traditionally been used for rapid prototyping activities, the technology is increasingly being adopted to produce commercial and industrial parts of any number of complex shapes. Additive manufacturing processes are typically performed by building a part layer by layer, for example, by 1) depositing a stream of molten printing material derived from a continuous filament, or 2) sintering powdered particulates of the printing material using a laser. The layer-by-layer deposition is typically performed under computer control to deposit the printing material in precise locations based on a digital three-dimensional "blueprint" of the part to be manufactured, with consolidation of the printing material occurring as the material is deposited to form the printed part. The printing material that forms the body of the printed part may be referred to herein as the "build material."

[0003] Additive manufacturing processes that use a stream of molten printing material to form parts are sometimes referred to as "fused deposition modeling" or "fused filament manufacturing" processes. The molten printing material is formed by heating thermoplastic polymer filaments, which are then deposited layer by layer and coalesce to form a consolidated part with a specific shape. Other additive manufacturing techniques rely on heating to consolidate polymer particles, including powder bed fusion (PBF), selective laser sintering (SLS), electron beam melting (EBM), binder jetting and multi-jet fusion (MJF), liquid bath photopolymerization, and directed energy deposition.

[0004] As additive manufacturing technologies become increasingly popular in commercial, educational, and home environments, there is an increasing focus on improving operational safety. One problem that can be encountered in these technologies is the generation of volatile organic compounds (VOCs), particularly during heating of printing materials such as polymer filaments, polymer particulates, or polymer sheets to their softening temperatures for consolidation during at least the course of extrusion, printing, and additive manufacturing and similar processes. Thermoplastic polymers containing styrene or acrylic monomer units, such as poly(acrylonitrile-butadiene-styrene) (ABS), can liberate particularly harmful VOCs. To mitigate potential health impacts, additive manufacturing units can be equipped with air filters and / or operated in ventilated workspaces. However, these measures are cumbersome and may not be applicable in all environments. Summary of the Invention

[0005] The present disclosure relates to bio-based additives for reducing VOC emissions during additive manufacturing and methods for producing printed materials containing the bio-based additives.

[0006] In some embodiments, a polymer filament compatible with fused filament manufacturing comprises a thermoplastic polymer and a bio-based additive admixed with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions as determined by gas chromatography and measured relative to the thermoplastic polymer alone.

[0007] In some embodiments, a method for forming a polymer filament compatible with Melt Filament Manufacturing includes forming a melt mixture comprising a thermoplastic polymer and a bio-based additive, and extruding and cooling the melt mixture to form a polymer filament comprising the bio-based additive admixed with the thermoplastic polymer, wherein the bio-based additive is present in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions, as determined by gas chromatography and measured relative to the thermoplastic polymer alone.

[0008] In some embodiments, an additive manufacturing process includes providing a polymer filament comprising a thermoplastic polymer and a bio-based additive admixed with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions as determined by gas chromatography and measured relative to the thermoplastic polymer alone; heating the polymer filament above a softening temperature of the thermoplastic polymer to form a softened polymer material; and depositing the softened polymer material layer by layer to form a printed part. [Brief explanation of the drawings]

[0009] The following figures are included to illustrate certain aspects of the present disclosure and should not be viewed as exclusive embodiments. The disclosed subject matter is susceptible to considerable modification, alteration, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure.

[0010] [Figure 1] FIG. 1 is a diagram of an exemplary fused filament manufacturing process for producing printed parts using a build material and a removable support material.

[0011] [Figure 2] FIG. 1 illustrates an exemplary printed part having an overhang.

[0012] [Figure 3A] 1 shows TEM images of filaments of comparative examples and examples of the present disclosure. [Figure 3B] 1 shows TEM images of filaments of comparative examples and examples of the present disclosure. [Figure 3C] 1 shows TEM images of filaments of comparative examples and examples of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure relates generally to additive manufacturing, and more specifically to polymer filaments compatible with fused filament manufacturing that reduce volatile organic compound (VOC) emissions during printing.

[0014] Additive manufacturing (AM) is a growing field of techniques that can utilize a variety of powder-based and filament-based printing materials. While the number of available printing materials is expanding rapidly, the range of suitable polymers remains small compared to the range available for competing manufacturing techniques such as injection molding. With increasing use in commercial, educational, and home environments, environmental health and safety associated with AM processes are becoming increasingly important. AM processes can heat polymer feedstocks to degradation threshold temperatures during deposition and consolidation, raising recent concerns about aerosolized particulates and volatile organic compounds (VOCs). While VOC and particulate emissions can be addressed with proper ventilation and filtering, they can be cumbersome or expensive in some cases. Furthermore, operators may not be aware that such safety measures are necessary for some printing materials, and in non-industrial environments, ventilation may not be economically feasible and air quality monitoring and control may be more difficult.

[0015] This disclosure demonstrates that the inclusion of one or more bio-based additives within polymer filaments can surprisingly reduce VOC emissions during additive manufacturing, such as during fused filament fabrication. Without being limited by any particular theory, it is believed that the bio-based additives provide a carbon source that can effectively sequester VOCs and reduce their emissions into the environment. Advantageously, suitable bio-based additives can include various biowaste streams that are generated in large quantities from manufacturing processes that might otherwise be disposed of in landfills or require time-consuming biorecycling operations, such as composting. Suitable bio-based additives can include, for example, coffee grounds and / or spent brewer's grains. Incorporating such bio-based additives into polymer filaments suitable for additive manufacturing can improve the environmental impact of additive manufacturing processes and provide a step toward a circular economy and more efficient use of resources. As yet another advantage, polymer filaments with bio-based additives combined therewith can continue to expand the breadth of polymeric materials available for use in various additive manufacturing processes.

[0016] Terms used in the description and claims of this specification have their plain and ordinary meanings, except as modified by the following explanations.

[0017] As used herein, the term "thermoplastic polymer" refers to a polymeric material that reversibly softens and hardens upon heating and cooling. Thermoplastic polymers include thermoplastic elastomers.

[0018] As used herein, the term "total volatile organic compounds" (TVOCs) is used to describe the group of organic compounds present in atmospheric emissions or ambient air. TVOCs are the sum of the contributions of various types of organic compounds emitted from a sample, including very volatile organic compounds (VVOCs), which have a typical boiling point between about 0°C and about 100°C and contain less than six carbon atoms; volatile organic compounds (VOCs), which have a typical boiling point between about 100°C and about 260°C and contain between six and sixteen carbon atoms; and semi-volatile organic compounds (SVOCs), which have a typical boiling point between about 260°C and about 400°C and contain sixteen or more carbon atoms.

[0019] Melting points of thermoplastic polymers are determined by ASTM E794-06(2018) at heating and cooling rates of 10°C / min unless otherwise specified.

[0020] The softening temperature or softening point of a thermoplastic polymer is determined by ASTM D6090-17 unless otherwise specified. Softening temperature can be measured using a cup and ball apparatus available from Mettler-Toledo using a 0.50 gram sample at a heating rate of 1°C / min.

[0021] VOC emissions from the polymer filaments and additive manufacturing processes disclosed herein can be determined using any suitable technique for detecting emissions from materials and products. In one method, VOCs can be detected by gas chromatography and / or mass spectrometry, during which VOCs can be measured under heating conditions that simulate additive manufacturing conditions used to promote part consolidation. For example, to determine VOCs, a sample can be heated from 230°C to 260°C at a ramp rate of 3°C / min, and volatiles can be collected and analyzed over this temperature range. The resulting data is reported as total TVOCs in μg per gram of sample.

[0022] Other suitable methods for measuring VOC emissions include ASTM D5116-17 and UL 2904 - "Method for Testing and Assessing Particle and Chemical Emissions from 3D Printers." Instruments that can be utilized to measure TVOCs include any suitable system for quantifying volatile organics, such as halocarbons, alcohols, terpenes, aldehydes, ketones, ethers, siloxanes, and the like. Test systems may include, but are not limited to, liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GCMS), liquid chromatography with tandem mass spectrometry (LC / MS / MS), gas chromatography with tandem mass spectrometry (GC / MS / MS), or high performance liquid chromatography with tandem mass spectrometry (HPLC-LC / MS / MS), gas chromatography with tandem mass spectrometry in electron capture negative ionization mode (GC / MSECNI), etc.

[0023] Before discussing various aspects of the present disclosure in more detail, a brief discussion of additive manufacturing processes, and in particular fused filament fabrication processes, will first be provided so that the features of the present disclosure may be better understood. FIG. 1 is a schematic diagram of an exemplary fused filament fabrication process for producing a part using a build material and a removable support material. As shown in FIG. 1, a print head 100 includes a first extruder 102a and a second extruder 102b, each configured to receive a fibrous printing material. Specifically, the first extruder 102a is configured to receive a first filament 104a from a first payout reel 106a and provide a molten stream 108a of the first printing material, and the second extruder 102b is configured to receive a second filament 104b from a second payout reel 106b and provide a molten stream 108b of the second printing material.

[0024] Both melt streams are initially deposited on a print bed (not shown in FIG. 1 ) to facilitate the layer-by-layer growth of the supported part 120. The first printing material (build material) supplied by the first extruder 102a may be a polymer used to fabricate the part 110, and the second printing material (removable support material) supplied by the second extruder 102b may be a dissolvable or degradable polymer that is a sacrificial material used to fabricate the removable support 112 under the overhang 114. The overhang 114 is not in direct contact with the print bed or the underlying print layer formed from the build material. In the part configuration shown in FIG. 1 , the removable support 112 is interposed between the overhang 114 and the print bed; however, it should be understood that in alternatively configured parts, the removable support 114 may be interposed between two or more portions of the part 110. FIG. 2, for example, shows an exemplary part 200 in which a removable support 202 is interposed between an overhang defined between the part 200 and a print bed 204, and a removable support 206 is interposed between two portions of the part 200.

[0025] 1 , once printing of the printed part 110 and removable support 112 is complete, the supported part 120 may be subjected to support removal conditions 125 (e.g., dissolution or disintegration conditions, etc.) that result in removal of the removable support 112, leaving the printed part 110 with the overhang 114 unsupported thereon. Support removal conditions 125 may include, for example, contacting the supported part 120 with a solvent or other liquid medium in which the removable support 112 is dissolvable or disintegrable, and the printed part 110 is not. The removable support 112 may comprise a different thermoplastic polymer than the printed part 110 to support selective dissolution or disintegration.

[0026] If the printed part is formed without overhangs or similar features, it is not necessary to utilize a removable support material during the manufacture of the printed part. Similarly, two or more different build materials may be utilized as well, such as when one or more build materials are structural in nature and one or more build materials are functional in nature. In a non-limiting example, a structural polymer may be simultaneously printed with a bio-based additive admixed therewith in accordance with the present disclosure.

[0027] The disclosed polymer filaments suitable for fused filament manufacturing may include a thermoplastic polymer and a bio-based additive blended with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions under additive manufacturing conditions, such as during fused filament manufacturing. It should be understood that the concepts disclosed herein may also be applicable to additive manufacturing processes using particle compaction. Reduced TVOC emissions may be measured relative to the thermoplastic polymer alone, with the TVOC reduction being at least about 10% by weight. TVOC measurements and reductions may be measured by gas chromatography and / or mass spectroscopy under heating conditions simulating additive manufacturing conditions. In particular, TVOC measurements may be obtained by heating a sample from 230°C to 260°C at a 3°C / min ramp rate and collecting and analyzing the volatiles emitted over this temperature range. The resulting data may be reported as total TVOC in μg per gram of sample.

[0028] Polymer filaments suitable for additive manufacturing can range in diameter from about 0.5 mm to about 10 mm, from about 1 mm to about 5 mm, and particularly from about 1.5 mm to about 3.5 mm. Standard filament diameters for many three-dimensional printers using fused filament fabrication techniques are 1.75 mm or 2.85 mm (about 3.0 mm). While some general ranges are provided, polymer filament diameters can be sized according to the drive system for a selected printer system without departing from the scope of this disclosure. Similarly, the length and / or color of the polymer filament is not considered particularly limited in the processes disclosed herein. Preferably, the polymer filaments disclosed herein are of a continuous and spoolable length, e.g., at least about 0.3 m, or at least about 2 m, or at least about 3 m, or at least about 4 m, or at least about 10 m, or at least about 30 m, or at least about 60 m, or at least about 100 m, or at least about 200 m.

[0029] Other properties that may determine whether a polymer filament is suitable for additive manufacturing, particularly fused filament manufacturing, include the temperature required for extrusion of the filament, which temperature is not unnecessarily high. Suitable filaments for fused filament manufacturing can minimize printing problems such as weeping or clogging of the print nozzle. Materials suitable for inclusion in the polymer filaments disclosed herein can form parts that easily separate from the print bed, have sufficient mechanical strength once printed, and exhibit good interlayer adhesion. Additional properties of suitable polymer filaments are specified below.

[0030] Thermoplastic polymers suitable for inclusion within the polymer filaments of the present disclosure are believed to be without particular limitation, provided that the bio-based additive can be blended therewith through a suitable blending process, such as melt blending, in an amount effective to reduce TVOCs under additive manufacturing conditions. Some examples of suitable thermoplastic polymers may exhibit a softening temperature or melting point sufficient to facilitate deposition at temperatures ranging from about 50°C to about 400°C, or from about 70°C to about 275°C, or from about 100°C to about 200°C, or from about 175°C to about 250°C. Melting points can be determined using ASTM E794-06(2018) with a 10°C heating and cooling rate, and softening temperatures can be determined using ASTM D6090-17.

[0031] Illustrative examples of suitable thermoplastic polymers include those commonly used in fused filament manufacturing, such as polyamides, polycaprolactone, polylactic acid, poly(styrene-isoprene-styrene) (SIS), poly(styrene-ethylene-butylene-styrene) (SEBS), poly(styrene-butylene-styrene) (SBS), high-impact polystyrene (high-impact Examples of suitable thermoplastic polymers include polystyrene (HIPS), polystyrene, thermoplastic polyurethane, poly(acrylonitrile-butadiene-styrene) (ABS), polymethyl methacrylate, poly(vinylpyrrolidine-vinyl acetate), polyester, polycarbonate, polyethersulfone, polyoxymethylene, polyetheretherketone, polyetherimide, polyethylene, polyethylene oxide, polyphenylene sulfide, polypropylene, polystyrene, polyvinyl chloride, poly(tetrafluoroethylene), poly(vinylidene fluoride), poly(vinylidene fluoride-hexafluoropropylene), polyvinylpyrrolidone-co-polyvinyl acetate (acrylonitrile-butadiene-styrene, PVP-co-PVA), any copolymers thereof, and any combinations thereof. In some examples, the thermoplastic polymer can be a styrene polymer such as poly(acrylonitrile-butadiene-styrene). In other specific examples, the thermoplastic polymer is not polylactic acid.

[0032] Suitable bio-based additives for incorporation into the polymer filaments disclosed herein may include biologically derived materials having various compositions and concentrations of carbonaceous compounds, including, but not limited to, cellulose, hemicellulose, lignin, proteins, etc. Once procured, suitable bio-based additives may undergo one or more pre-treatment operations, such as disinfection and / or sterilization by physical or chemical methods, clarification, grinding, sieving, screening, pressing to remove excess oil, washing, solvent extraction to remove organic matter, drying, etc., before being mixed with the thermoplastic polymer.

[0033] Pretreatment of the bio-based additive can include removing water therefrom by any suitable method to remove excess fluid and moisture, including dehydration by air drying, vacuum drying, and / or freeze-drying (lyophilization). Suitable bio-based additives, optionally after pretreatment, can have a moisture content of about 0.1% by weight or less, about 0.5% by weight or less, or about 1% by weight or less.

[0034] Pre-processing of the bio-based additive may additionally or alternatively include reducing the particle size of the bio-based additive by any suitable method, such as cutting, grinding, cryogenic grinding, milling, crushing, pulverizing, sonication, homogenization, and similar particle size reduction techniques. Particle size reduction may help enhance dispersion of the bio-based additive within the thermoplastic polymer during melt mixing. Bio-based additives suitable for use in the present disclosure may have an average particle size in the micrometer or nanometer size range. In certain examples, suitable bio-based additives have an average particle size (D) of about 16 μm or less, or about 14 μm or less, or about 10 μm or less. 50 Some examples of bio-based additives may have an average particle size (D) ranging from about 0.1 μm to about 20 μm, from about 0.4 μm to about 14 μm, or from about 0.4 μm to about 10 μm. 50Such average particle size measurements may be performed by analysis of optical images, including SEM analysis, or using the on-board software of a Beckman Coulter Multisizer 3. While several particle sizes and ranges are provided, the particle sizes may be larger or smaller depending on application-specific needs, such as feeding requirements for the selected additive manufacturing platform, the properties of the thermoplastic polymer, etc.

[0035] Bio-based additives suitable for use in the present disclosure may include grains, processed grains, grain waste, and grain by-products. Examples may include, but are not limited to, distillers' products, brewer's spent grain, corn gluten, sorghum germ cake and meal, peanut hulls, and wheat bran. Suitable grains, grain waste, and the like may be derived from any one or more of barley, corn, oats, rice, sorghum, wheat, any mixture thereof, and the like. Some polymer filaments of the present disclosure may include brewer's spent grain, which may be derived from the beer brewing process. Additional bio-based additives suitable for use in the present disclosure may include coffee beans and coffee grounds (including spent coffee grounds). These bio-based additives may be used alone or in combination with grains, grain waste, and the like in the polymer filaments disclosed herein.

[0036] Still other biobased additives include vegetable protein products such as canola meal, cottonseed cake and meal, safflower meal, soybean (including organic and genetically modified soybeans) feed and meal, and other vegetable protein products such as alfalfa, bird's foot trefoil, brassicas (e.g., chamomile), kale, rapeseed (canola), rutabaga, and turnips, grasses (e.g., black locust, fescue, bermudagrass, brome, heathgrass, meadowgrass, orchard grass, and oak leaf grass). fibrous materials such as plant materials such as corngrass, ryegrass, and timothy grass), millet, and soybeans; husks and fibrous substances such as grasses, rice husks, cotton, jute, hemp, flax, bamboo, sisal, abaca, straw, corn cobs, rice husks, coconut hair, algae, seaweed, water hyacinth, cassava, bagasse, almond shells, oat husks, buckwheat husks, pulses, synthetic cellulose; processed and recycled paper products, wood, wood-related materials, particle board, and the like may be mentioned.

[0037] The loading of bio-based additives in the polymer filaments disclosed herein can be adjusted to achieve the desired degree of TVOC reduction. In illustrative examples, the bio-based additive can be present in an amount effective to achieve at least about 10% TVOC reduction, or about 25% TVOC reduction, or at least about 40% TVOC reduction, or at least about 60% TVOC reduction, or at least about 80% TVOC reduction. The reduction rate is calculated using the formula |TVOC poly -TVOC fil │ / TVOC poly In the formula, TVOC poly is the TVOC of the polymer alone, and filis the TVOC of a polymer filament containing a bio-based additive. In some examples, the bio-based additive may comprise about 0.5 wt.% or more, or about 1 wt.% or more, or about 2 wt.% or more, or about 5 wt.% or more, or about 10 wt.% or more of a polymer filament of the present disclosure (or a polymer melt used to form the polymer filament). In more specific examples, the bio-based additive may be present in the polymer filament (or a polymer melt used to form the polymer filament) in an amount ranging from about 0.5 wt.% to about 10 wt.%, or from about 0.5 wt.% to about 7.5 wt.%, or from about 1 wt.% to about 5 wt.%, or from about 1 wt.% to about 4 wt.%. While several ranges are provided as examples, the loading of the bio-based additive may be selected such that the polymer filament maintains structural integrity as a continuous filament and remains printable by fused filament manufacturing, as specified herein, while still reducing TVOC emissions during additive manufacturing.

[0038] The polymer filaments of the present disclosure can be formed by a melt-blending process. A suitable melt-blending process can involve melt-blending a thermoplastic polymer with a bio-based additive, followed by extrusion of the resulting melt-blending mixture. Alternatively, melt-blending can be performed directly via extrusion in an extruder. During filament extrusion, a thermoplastic polymer can be melt-blended with one or more bio-based additives and any additional optional additives in an extruder, such as a single-screw or multi-screw extruder, and mechanically passed through a die. The molten polymer mixture can be sized according to one or more openings in the die to form a continuous polymer filament. Once the polymer filament cools, it can be collected and spooled into a form suitable for the end-use application, such as feeding a printing device for molten filament production. Additionally, the melt-blended polymer composition can also be converted into other forms, including pelletized forms, depending on the application, without departing from the present disclosure.

[0039] Thus, a method for forming a polymer filament according to the present disclosure includes forming a melt mixture including a thermoplastic polymer and a bio-based additive, and extruding and cooling the melt mixture to form a polymer filament including the bio-based additive admixed with the thermoplastic polymer, wherein the bio-based additive is present in an amount effective to reduce TVOC emissions under additive manufacturing conditions by at least about 10% on a weight basis, as determined by gas chromatography and measured relative to the thermoplastic polymer alone.

[0040] Additive manufacturing processes performed by fused filament fabrication according to the present disclosure can include providing a polymer filament as described herein, heating the polymer filament above its melting point or softening temperature to form a softened polymer material, and depositing the softened polymer material layer by layer to form a printed part. The polymer filament can be deposited layer by layer by itself or in combination with a suitable removable support material (sacrificial material) also deposited from a continuous filament to form the printed part. Suitable types of parts are not considered to be particularly limiting in this disclosure.

[0041] In some fused filament manufacturing methods, a print head can include one or more extruders such that a first polymer filament including a build material is deposited from a first extruder. The build material can include a polymer filament according to the disclosure above. Optionally, a second polymer filament including a removable support material (sacrificial material) can be deposited from a second extruder to form a removable support for defining one or more overhangs in a printed part formed from the build material. The second build material can also be deposited alternately with the polymer filaments disclosed herein.

[0042] While polymer filaments can be particularly advantageous when formed according to the disclosure herein, it should be understood that polymer compositions containing bio-based additives can be formed into other shapes, including pellets or particles, after melt blending. For example, a thermoplastic polymer and one or more bio-based additives can be melt blended and then extruded into large fibers, which can then be cut, chopped, ground, or the like to obtain polymer pellets or polymer powders, each containing the bio-based additives blended with the polymer. The morphology of the polymer pellets or polymer powders can be similar to that of polymer filaments suitable for additive manufacturing. Like polymer filaments, the polymer pellets or polymer powders can then be processed into printed parts under suitable additive manufacturing conditions.

[0043] In addition to additive manufacturing, polymer pellets (or other polymer compositions) incorporating a thermoplastic polymer and a bio-based additive incorporated therein in an amount effective to reduce TVOC emissions may be amenable to other manufacturing techniques such as, for example, extrusion, co-extrusion, extrusion coating, injection molding, injection blow molding, injection stretch blow molding, thermoforming, cast film extrusion, blown film extrusion, foaming, extrusion blow molding, injection stretch blow molding, rotational molding, pultrusion, calendering, lamination, etc.

[0044] Embodiments disclosed herein include the following.

[0045] A. A polymer filament compatible with fused filament manufacturing, the polymer filament comprising a thermoplastic polymer and a bio-based additive admixed with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions, as determined by gas chromatography and measured relative to the thermoplastic polymer alone.

[0046] B. A method for forming a polymer filament compatible with fused filament manufacturing, the method comprising: forming a melt mixture comprising a thermoplastic polymer and a bio-based additive; and extruding and cooling the melt mixture to form a polymer filament comprising the bio-based additive admixed with the thermoplastic polymer, wherein the bio-based additive is present in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions, as determined by gas chromatography and measured relative to the thermoplastic polymer alone.

[0047] C. Additive Manufacturing Process. The additive manufacturing process includes providing a polymer filament including a thermoplastic polymer and a bio-based additive admixed with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions as determined by gas chromatography and measured relative to the thermoplastic polymer alone, heating the polymer filament above a softening temperature of the thermoplastic polymer to form a softened polymeric material, and depositing the softened polymeric material layer by layer to form a printed part.

[0048] Each of embodiments A, B, and C may have one or more of the following additional elements in any combination.

[0049] Element 1: The bio-based additive is present in an amount effective to reduce TVOC emissions by at least about 25% on a weight basis.

[0050] Element 2: The bio-based additive is blended with the thermoplastic polymer at about 1% by weight or greater based on the total weight.

[0051] Element 3: The bio-based additive is freeze-dried.

[0052] Element 4: The bio-based additive contains about 1% or less water by weight.

[0053] Element 5: The bio-based additive has an average particle size of about 14 μm or less.

[0054] Element 6: The bio-based additive has an average particle size of about 0.4 μm to about 14 μm.

[0055] Element 7: The bio-based additive includes coffee grounds, grain waste, or any combination thereof.

[0056] Element 8: Bio-based additives include brewer's spent grain.

[0057] Element 9: The thermoplastic polymer comprises a polymer selected from the group consisting of polyamide, polycaprolactone, poly(styrene-isoprene-styrene) (SIS), poly(styrene-ethylene-butylene-styrene) (SEBS), poly(styrene-butylene-styrene) (SBS), high impact polystyrene, polystyrene, thermoplastic polyurethane, poly(acrylonitrile-butadiene-styrene) (ABS), polymethyl methacrylate, poly(vinylpyrrolidine-vinyl acetate), polyester, polycarbonate, polyethersulfone, polyoxymethylene, polyetheretherketone, polyetherimide, polyethylene, polyethylene oxide, polyphenylene sulfide, polypropylene, polystyrene, polyvinyl chloride, poly(tetrafluoroethylene), poly(vinylidene fluoride), poly(vinylidene fluoride-hexafluoropropylene), any copolymer thereof, and any combination thereof.

[0058] Element 10: The thermoplastic polymer is a poly(acrylonitrile-butadiene-styrene) polymer.

[0059] Element 11: The thermoplastic polymer is not polylactic acid.

[0060] As a non-limiting example, exemplary combinations applicable to A, B, and C include: 1 and 2; 1 and 3 or 4; 1 and 5 or 6; 1 and 7 or 8; 1 and 9; 1 and 10; 1 and 11; 2 and 3 or 4; 2 and 5 or 6; 2 and 7 or 8; 2 and 9; 2 and 10; 2 and 11; 3 or 4 and 5 or 6; 3 or 4 and 7 or 8; 3 or 4 and 9; 3 or 4 and 10; 3 or 4 and 11; 5 or 6 and 7 or 8; 5 or 6 and 9; 5 or 6 and 10; 5 or 6 and 11; 7 or 8 and 9, 7, 8 or 10; 7 or 8 and 11; 9 and 10; 9 and 11; and 10 and 11.

[0061] To facilitate a better understanding of the present disclosure, the following examples of preferred or representative embodiments are given, which should in no way be read as limiting or defining the scope of the invention. [Example]

[0062] In the following examples, polymer filaments were prepared using poly(acrylonitrile-butadiene-styrene) (ABS) polymer blended with selected bio-based additives, as further specified below. Sample polymer filaments were prepared using a Filabot EX6 filament device equipped with a single-screw extruder within a barrel heated to 185°C. The sample ingredients were loaded into the device and blended, and the filaments were extruded through a 2.85 mm die, air-cooled, and wound onto a spool.

[0063] Comparative Sample: A comparative sample polymer filament was prepared by extruding ABS alone. The filament was white in color.

[0064] Sample 1: ABS-brewer's spent grain (beer brewery waste). The polymer filaments of Sample 1 were made from ABS containing 4% by weight of brewer's spent grain (beer brewery waste). Before combining with the ABS, the brewer's spent grain was dehydrated by freeze-drying for 3 days to a moisture content of less than 1%. The dried ground material was then transferred to a blade grinder, ground, and sieved through a 58 μm sieve. As determined by particle analysis using a Multisizer 3 (Beckman Coulter), the particles were D 50 The diameter was less than 14 μm. The obtained filament was light brown in color, and specks of bio-based additives were observed on the surface.

[0065] Sample 2: ABS - Used Coffee Grounds. Sample 2 polymer filaments were produced from ABS containing 4% by weight of used coffee grounds. Prior to combining with the ABS, the used coffee grounds were dried for 24 hours using a dehydrator to reduce the moisture content to less than 1%. The dried grounds were then transferred to a blade grinder, ground, and sieved through a 58 μm sieve. As determined by particle analysis using a Multisizer 3 (Beckman Coulter), the particles were D 50 The diameter was less than 11 μm. The obtained filament was light brown in color, and specks of bio-based additives were observed on the surface.

[0066] 3A, 3B, and 3C show transmission electron microscopy (TEM) images of the filaments of the comparative sample, Sample 1, and Sample 2. White areas in the TEM images indicate porosity in the filaments. As shown, the samples containing the bio-based additive exhibited a lower degree of porosity, with Sample 2 visually exhibiting the least porosity.

[0067] Test Specimens. Dogbone test specimens for Sample 1, Sample 2, and the comparative sample were produced according to ASTM D638-14 using an Ultimizer S5 3-D printer. Printing was performed at a print head temperature of 240°C, a bed temperature of 80°C, and a line height of 0.2 mm. The tensile strength of the test specimens was measured according to ASTM D638. All samples exhibited similar mechanical property performance.

[0068] TVOC Measurement. Polymer filaments were analyzed under heating conditions intended to mimic additive manufacturing conditions suitable for printing ABS filaments. Under simulated additive manufacturing conditions, samples were heated from 230°C to 260°C at a heating rate of 3°C / min, and volatiles were collected during this temperature range to determine TVOC emissions. TVOC emissions were measured using a gas chromatograph / mass spectrometer.

[0069] The measured TVOC emissions are summarized in Table 1 below. The TVOC measurements of the comparative samples were used to determine the percent difference and percent reduction in TVOC emissions for Sample 1 and Sample 2. The percent reduction was calculated using the formula |TVOC poly -TVOC fil │ / TVOC poly The difference rate is determined by the formula TVOC poly -TVOC fil │ / (TVOC poly +TVOC fil ) / 2, where TVOC poly is the TVOC of the polymer alone, and fil is the TVOC of the polymer filament containing the bio-based additive. [Table 1]

[0070] The individual reductions of styrene relative to the comparative samples were also analyzed by GC / MS, showing a reduction of 38% for each of Samples 1 and 2 under additive manufacturing conditions, as shown in Table 2. [Table 2]

[0071] All documents described herein are incorporated by reference for purposes of all jurisdictions where such practice is permitted, including any priority documents and / or testing procedures to the extent not inconsistent with this text. While forms of the disclosure have been illustrated and described, as is apparent from the foregoing general description and specific embodiments, various modifications can be made without departing from the spirit and scope of the disclosure. Accordingly, the disclosure is not intended to be limited thereby. For example, the compositions described herein may not include any component or composition not expressly listed or disclosed herein. Any method may lack any step not listed or disclosed herein. Similarly, the term "comprising" is considered synonymous with the term "including." Whenever a method, composition, element, or group of elements is preceded by the transitional phrase "comprising," it is understood that the inventors also contemplate the same composition or group of elements with the transitional phrase "consisting essentially of," "consisting of," "selected from the group consisting of," or "being" preceding the composition, element, or list of elements, and vice versa.

[0072] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and the like used in this specification and the related claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0073] Whenever a numerical range with a lower and upper limit is disclosed, any number within that range and any included range is specifically disclosed. In particular, all ranges of values ​​disclosed herein (in the form "from about a to about b," or, equivalently, "approximately a to b," or, equivalently, "from approximately a to b") should be understood to describe all numbers and ranges encompassed within that broad range of values. Furthermore, terms in the claims have their plain and ordinary meaning unless expressly and unambiguously defined otherwise by the patentee. Additionally, when used in the claims, the indefinite article "a" or "an" is defined herein to mean one or more than one of the element it introduces.

[0074] One or more exemplary embodiments are presented herein. For clarity, not all features of a physical implementation are described or shown in this application. It is understood that in developing a physical embodiment of the present disclosure, numerous implementation-specific decisions must be made to achieve the developer's goals, which may vary from implementation to implementation and from time to time, such as compliance with system-related, business-related, government-related, and other constraints. While the developer's efforts may be time-consuming, such efforts would nevertheless be routine for one of ordinary skill in the art having the benefit of this disclosure.

[0075] Thus, the present disclosure is well adapted to achieve the ends and advantages mentioned, as well as those inherent therein. The specific embodiments described above are illustrative only, as the disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design shown herein, other than as described in the following claims. It is therefore evident that the specific exemplary embodiments disclosed above may be altered, combined, or modified, and all such variations are considered within the scope and spirit of the present disclosure. The embodiments illustratively disclosed herein may suitably be practiced in the absence of any element not specifically disclosed herein and / or any optional element disclosed herein. Another aspect of the present invention may be as follows. [1] A polymer filament suitable for fused filament manufacturing, a thermoplastic polymer; a bio-based additive admixed with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions, as determined by gas chromatography and measured relative to the thermoplastic polymer alone. [2] The polymer filament described in [1], wherein the bio-based additive is admixed with the thermoplastic polymer at a concentration of about 1% by weight or more based on the total mass. [3] The polymer filament described in [1], wherein the bio-based additive contains less than about 1% by weight of water. [4] The polymer filament described in [1], wherein the bio-based additive has an average particle size of about 14 μm or less. [5] The polymer filament according to [1], wherein the bio-based additive comprises coffee grounds, grain waste, or any combination thereof. [6] The polymer filament described in [1], wherein the bio-based additive comprises brewer's spent grain. [7] The polymer filament according to [1], wherein the thermoplastic polymer comprises a polymer selected from the group consisting of polyamide, polycaprolactone, poly(styrene-isoprene-styrene) (SIS), poly(styrene-ethylene-butylene-styrene) (SEBS), poly(styrene-butylene-styrene) (SBS), high-impact polystyrene, polystyrene, thermoplastic polyurethane, poly(acrylonitrile-butadiene-styrene) (ABS), polymethyl methacrylate, poly(vinylpyrrolidine-vinyl acetate), polyester, polycarbonate, polyethersulfone, polyoxymethylene, polyetheretherketone, polyetherimide, polyethylene, polyethylene oxide, polyphenylene sulfide, polypropylene, polystyrene, polyvinyl chloride, poly(tetrafluoroethylene), poly(vinylidene fluoride), poly(vinylidene fluoride-hexafluoropropylene), any copolymer thereof, and any combination thereof. [8] The polymer filament described in [1], wherein the thermoplastic polymer is a poly(acrylonitrile-butadiene-styrene) polymer. [9] The polymer filament described in [1], wherein the thermoplastic polymer is not polylactic acid.

[10] A method for forming a polymer filament compatible with fused filament manufacturing, comprising: forming a molten mixture comprising a thermoplastic polymer and a bio-based additive; extruding and cooling the molten mixture to form a polymer filament comprising the bio-based additive admixed with the thermoplastic polymer; the bio-based additive is present in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions, as determined by gas chromatography and measured relative to the thermoplastic polymer alone.

[11] The method according to

[10] , wherein the bio-based additive contains about 1% by weight or less of water.

[12] The method according to

[10] , wherein the bio-based additive has an average particle size of about 14 μm or less.

[13] The method according to

[10] , wherein the bio-based additive comprises coffee grounds, grain waste, or any combination thereof.

[14] The method according to

[10] , wherein the bio-based additive comprises brewer's spent grain.

[15] The method according to

[10] , wherein the thermoplastic polymer is a poly(acrylonitrile-butadiene-styrene) polymer.

[16] The method according to

[10] , wherein the thermoplastic polymer is not polylactic acid.

[17] An additive manufacturing process, comprising: providing a polymer filament comprising a thermoplastic polymer and a bio-based additive admixed with the thermoplastic polymer in an amount effective to reduce total volatile organic compound (TVOC) emissions by at least about 10% by weight under additive manufacturing conditions as determined by gas chromatography and measured relative to the thermoplastic polymer alone; heating the polymer filaments above a softening temperature of the thermoplastic polymer to form a softened polymer material; and depositing the softened polymeric material layer by layer to form a printed part.

[18] The method according to

[17] , wherein the bio-based additive comprises coffee grounds, grain waste, or any combination thereof.

[19] The method according to

[17] , wherein the bio-based additive comprises brewer's spent grain.

[20] The method according to

[17] , wherein the thermoplastic polymer is a poly(acrylonitrile-butadiene-styrene) polymer.

Claims

1. 1. A polymer filament suitable for fused filament manufacturing, comprising: a thermoplastic polymer that is not polylactic acid; a bio-based additive admixed with the thermoplastic polymer; 1) the bio-based additive comprises coffee grounds, grain waste, or any combination thereof, and the thermoplastic polymer is a poly(acrylonitrile-butadiene-styrene) polymer; or 2) the bio-based additive comprises brewer's spent grain; The bio-based additive is blended with the thermoplastic polymer at 1% to 5% by weight based on the total weight; and The polymer filament has a diameter ranging from 1.5 mm to 3.5 mm.

2. 10. The polymer filament of claim 1, wherein the bio-based additive has an average particle size of 14 μm or less.

3. 1. A method for forming polymer filaments compatible with fused filament manufacturing, comprising: forming a melt mixture comprising a thermoplastic polymer that is not polylactic acid and a bio-based additive; extruding and cooling the molten mixture to form a polymer filament comprising the bio-based additive admixed with the thermoplastic polymer; 1) the bio-based additive comprises coffee grounds, grain waste, or any combination thereof, and the thermoplastic polymer is a poly(acrylonitrile butadiene styrene) polymer; or 2) the bio-based additive comprises brewer's spent grain; the polymer filament has a diameter ranging from 1.5 mm to 3.5 mm; and The method wherein the bio-based additive is admixed with the thermoplastic polymer at 1% to 5% by weight based on the total weight.

4. The method of claim 3, further comprising drying the bio-based additive to a moisture content of 1% by weight or less before being mixed with the thermoplastic polymer.

5. 4. The method of claim 3, wherein the bio-based additive has an average particle size of 14 μm or less.

6. 1. An additive manufacturing process comprising: providing a polymer filament comprising a thermoplastic polymer and a bio-based additive admixed with the thermoplastic polymer; heating the polymer filaments above a softening temperature of the thermoplastic polymer to form a softened polymer material; and depositing the softened polymeric material layer by layer to form a printed part; The thermoplastic polymer is not polylactic acid, the bio-based additive is blended with the thermoplastic polymer at 1% to 5% by weight based on the total weight; 1) the bio-based additive comprises coffee grounds, grain waste, or any combination thereof, and the thermoplastic polymer is a poly(acrylonitrile-butadiene-styrene) polymer; or 2) the bio-based additive comprises brewer's spent grain; and The process wherein the polymer filaments have a diameter ranging from 1.5 mm to 3.5 mm.

Images