Thermally stable water-soluble polymer compositions

Abstract

A thermally stable water-soluble polymer composition comprises at least one water-soluble polymer and at least one reinforcing filler. A thermally stable water-soluble polymer composition comprising at least one water-soluble polymer and at least one reinforcing filler, capable of addressing several additive manufacturing issues: such a composition can dissolve or disintegrate in water at neutral pH, can be compatible with hydrophilic and hydrophobic polymers, and can be used as a water-soluble polymer or a water-soluble polymer. In particular, the present invention relates to a polymer, a polymer, and a method for preparing the polymer, and may be used as a support material for a build chamber temperature of at least about 180 DEG C, having a modulus of greater than 1 * 106 Pa at a print chamber temperature, and being readily removable (soluble / disintegrable) after printing at the build chamber temperature for at least 24 hours, all of which are desirable, for example, in 3D printing of high temperature engineering thermoplastics.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of U.S. Provisional Application No. 63 / 415,676, filed on October 13, 2022, which is incorporated herein by reference. Technical field

[0003] The present disclosure relates to compositions and methods for preparing and using thermally stable water - soluble polymer compositions. Background art

[0004] Additive manufacturing processes, commonly referred to as three - dimensional (3D) printing, can be used to build desired objects that may have applications in many industries (e.g., aerospace, automotive, medical, etc.). Exemplary processes include, but are not limited to, binder jetting, electron beam melting (EBM), fused deposition modeling (FDM), fused filament fabrication (FFF), direct extrusion, inkjet, laminated object manufacturing (LOM), selective laser sintering (SLS), selective toner electrophotographic process (STEP), and stereolithography (SL). Using such processes, a desired object can be modeled in a computer - aided design (CAD) package and printed using a selected build material. For deposition - based methods (e.g., FDM), the selected build material is typically extruded through a heated printer in a layer - by - layer manner according to computer instructions. Printing in commercially available additive manufacturing devices (e.g., the ARBURG TM Freeformer system) typically occurs in a build chamber capable of providing heating and temperature control.

[0005] Many additive manufacturing techniques use support layers or structures to build a desired object. However, the limited availability of suitable support methods, materials, and structures restricts 3D printing to certain design types. The most basic support method uses the same material as the printed object for support. With this technique, supports are erected in a manner similar to scaffolding on a building and "hold up" any overhangs or spans at steep angles. Known as "friable" or "raft" supports, this type of support can be effective but can also be messy, time-consuming, and difficult to remove by mechanical breaking or trimming. It is not uncommon to spend hours cleaning or cutting the support material from a 3D printed object using a blade, scalpel, sandpaper, or even power tools. Methods using different support and printing materials can also be problematic. For example, due to incompatibility between the support material and the base resin of 3D printing, it is almost impossible to print certain hydrophobic polymers (such as polypropylene).

[0006] The inability to remove internal support material further restricts object design types. Some external geometries make it difficult (if not impossible) to remove internal support material. For years, many have tried to solve this problem with support structures that are supposed to dissolve in very hot water, highly acidic or alkaline conditions, organic solvents, or various other chemicals. These products are generally messy, even dangerous - and overall unsuccessful. Another challenge is related to producing a support material that is not only water-soluble but also thermally stable for the printing conditions required for certain high-temperature engineering thermoplastics (such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylsulfone (PPSU), and polyetherimide (PEI)). Typically, such materials may require high melting temperatures (above 270 °C) and high printing chamber temperatures (above 180 °C) for long periods (>24 hours). The disclosure herein provides a material composition for a thermally stable water-soluble polymer composition that functions properly under these extreme conditions while maintaining adequate dissolution / removal characteristics after printing. Summary of the Invention

[0007] A thermally stable water-soluble polymer composition comprising at least one water-soluble polymer (such as sulfopolyester (SPE)) and at least one reinforcing filler (such as carbon nanotubes) can solve several additive manufacturing problems: such compositions can dissolve or disintegrate in water at room temperature at neutral pH, can be compatible with hydrophilic and hydrophobic polymers, can be used as a support material for build chamber temperatures of at least about 180 °C, and have a viscosity above 1×10 6a modulus of Pa and is readily removable (soluble / disintegratable) after printing for at least 24 hours at the build chamber temperature, all of which are desirable, for example, when 3D printing high-temperature engineering thermoplastics.

[0008] Furthermore, a heat-stable water-soluble polymer composition can be unique because such a composition can result in improved mechanical properties, temperature resistance, and functionality. Some embodiments have improved mechanical properties that make the heat-stable water-soluble polymer composition suitable for 3D printing using a filament-type printer, including modulus, storage modulus (at high temperatures), impact strength, tensile strength, and coefficient of linear thermal expansion (CLTE). For example, when a water-soluble polymer is melt-processed with a reinforcing filler, it can produce a heat-stable water-soluble polymer composition having an increased modulus at high build chamber temperatures, which is a desirable property for fused deposition modeling (FDM) and direct extrusion 3D printers.

[0009] In some embodiments, the heat-stable water-soluble polymer composition comprises at least one water-soluble polymer and at least one reinforcing filler. The water-soluble polymer and the reinforcing filler can be combined using conventional melt-processing techniques (such as twin-screw extrusion).

[0010] In some embodiments, a 3D printed article includes a 3D printed object typically deposited on a substantially horizontal build plate in a build chamber and one or more soluble supports positioned around and supporting one or more portions of the 3D printed object, the soluble supports comprising a heat-stable water-soluble polymer composition. The heat-stable water-soluble polymer composition can be formed by melt-processing a water-soluble polymer and a reinforcing filler. For example, the heat-stable water-soluble polymer composition can be substantially stable at a build chamber temperature of at least about 180°C. In other embodiments, the build material of the 3D printed article comprises a heat-stable water-soluble polymer composition.

[0011] In some embodiments, a heat-stable water-soluble support is formed by melt-processing a water-soluble polymer and a reinforcing filler. The water-soluble support is substantially dry and substantially stable at a build chamber temperature of at least about 180°C.

[0012] The foregoing summary is not intended to describe every disclosed embodiment or every implementation. The following detailed description more particularly illustrates illustrative embodiments.

[0013] Brief Description of the Drawings

[0014] Figure 1It is an image of a thermally stable water-soluble polymer composition printed using an Arburg Freeformer 300X at a chamber temperature of 140 °C.

[0015] Figure 2 It is an image of a thermally stable water-soluble polymer composition printed using an Arburg Freeformer 300X at a chamber temperature of 200 °C.

[0016] Figure 3 It is an image of a thermally stable water-soluble polymer composition printed using an Arburg Freeformer 300X with polyetherimide (PEI, ULTEM 9085) at a chamber temperature of 185 °C.

[0017] Figure 4 It is an image of a thermally stable water-soluble composition printed using an AON M2+ with polyetherketoneketone (PEKK) at a chamber temperature of 70 °C.

[0018] Figure 5 It is an image of a thermally stable water-soluble composition printed using an Arburg Freeformer 300X with polyetheretherketone (PEEK) at a chamber temperature of 200 °C.

[0019] Figure 6 It is an image of a thermally stable water-soluble composition printed on an AON M2+ with polyetherketoneketone (PEEK) at a chamber temperature of 65 °C.

[0020] Figure 7 It shows the resulting appearance of formulations 18 - 22 annealed for 0 and 24 hours. Detailed Description

[0021] Unless the context otherwise indicates, the following terms shall have the following meanings and shall apply to both the singular and plural:

[0022] The terms "a", "an", "one", "the", "at least one", and "one or more" and cases where no quantifier is used are interchangeable. Thus, for example, a thermally stable water-soluble polymer composition containing a water-soluble polymer means that the thermally stable water-soluble polymer composition can contain "one or more" water-soluble polymers.

[0023] The terms "additive manufacturing", "three-dimensional printing", "3D printing", or "3D printed" refer to any process for creating three-dimensional objects in which successive layers of material are formed under computer control (e.g., electron beam melting (EBM), fused deposition modeling (FDM), direct extrusion, inkjet, laminated object manufacturing (LOM), selective laser sintering (SLS), selective toner electrophotographic process (STEP), and stereolithography (SL)).

[0024] The term "build chamber" refers to the volume that is typically enclosed within or utilized by an additive manufacturing apparatus, within which a desired object can be printed. Non-limiting examples of build chambers can be found in the ARBURG TM Freeformer (commercially available from Arburg GmbH, Lossburg, Germany).

[0025] The term "build chamber temperature" refers to the temperature provided within the build chamber during additive manufacturing.

[0026] The term "build material" refers to the material that is printed in three dimensions using an additive manufacturing process to produce a desired object, typically remaining after removal of soluble supports.

[0027] The term "build plate" refers to the substrate on which the build material or soluble supports can be printed, typically a removable film or sheet.

[0028] The term "composition" refers to a multi-component material.

[0029] The term "copolymer" refers to a polymer that is actually (e.g., by copolymerization) or conceptually derived from more than one monomer. Copolymers obtained from two monomeric substances are sometimes called binary polymers; copolymers obtained from three monomers are sometimes called terpolymers; copolymers obtained from four monomers are sometimes called quaternary polymers; and so on. Copolymers can be characterized based on the arrangement of branches in the structure, including, for example, linear copolymers and branched copolymers. Copolymers can also be characterized based on how the monomer units are arranged, including, for example, alternating copolymers, periodic copolymers, statistical copolymers, graft copolymers, and block copolymers.

[0030] The term "crystalline" refers to a polymer composition having a crystallinity greater than 90%, e.g., measured by differential scanning calorimetry (DSC) in accordance with ASTM standard D3418 - 12 - "Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry".

[0031] The term "filler" refers to a material that is immiscible in a thermally stable water - soluble polymer composition and that modifies the end - use properties.

[0032] The term "feedstock" refers to the form of a material that can be used in an additive manufacturing process (e.g., as a build material or a soluble support). Non - limiting examples of feedstocks include pellets, powders, filaments, billets, liquids, sheets, formed profiles, etc.

[0033] The term "high - temperature thermoplastic" refers to a polymer or polymer composition that is typically melt - processed at about 220 °C or higher. Non - limiting examples of high - temperature thermoplastics include, but are not limited to, polycarbonate (PC), polyamide (nylon), polyester (PET), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polysulfone (PPSU), and polyetherimide (PEI).

[0034] The term "melt - processing technique" refers to a technique that applies thermal and mechanical energy to reshape, blend, mix, or otherwise reform a polymer or composition, such as compounding, extrusion, injection molding, blow molding, rotational molding, or batch mixing. An example of a melt - processing technique is a 3D printing process that can be used to print thermoplastic and elastomeric melt - processable materials.

[0035] The term "mixing" means combining or putting together to form a single substance, material, phase, complex, dispersion, or more homogeneous state. This can include, but is not limited to, all physical blending methods, extrusion techniques, or solution methods.

[0036] The term "monomer" refers to a molecule that can undergo polymerization to provide a structural unit to the basic structure of a polymer.

[0037] The terms "polymer" and "polymeric" refer to molecules of high relative molecular mass whose structure essentially contains (either actually or conceptually) multiple repeating units derived from low - relative - molecular - mass molecules (monomers). The term "polymer" can refer to a "copolymer".

[0038] The term "reinforcing filler" refers to a material that is not viscoelastic under the melt processing conditions for producing a thermally stable water-soluble polymer composition and has a diameter of less than 200 nm and an aspect ratio greater than 10:1.

[0039] The term "semicrystalline" refers to a polymer composition having a crystallinity greater than 5% but less than 90%, such as measured by differential scanning calorimetry (DSC) in accordance with ASTM standard D3418-12 - "Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry".

[0040] The term "soluble support", "soluble support material" or "water-soluble support" refers to a material that is printed in a three-dimensional manner using an additive manufacturing process to physically support or reinforce a build material during 3D printing and can be removed by chemical solvation or dissolution during or after the additive manufacturing process as needed.

[0041] The term "stabilizer" means one or more additives or materials that substantially (either in reality or conceptually) enhance the resistance of a polymer to degradation processes (mechanical, thermal, hydrolysis, acid / base, oxidation, free radicals, ultraviolet light or any other form of radiation).

[0042] The term "substantially dry" means that, under standard conditions, based on the weight of the thermally stable water-soluble polymer composition, the material contains about 15 wt% or less of volatiles, or about 10 wt% or less of volatiles.

[0043] The term "substantially stable" or "substantial stability" refers to a material that largely exhibits dimensional stability (e.g., has minimal flow, melting or deformation) at the print processing temperature (e.g., build chamber temperature).

[0044] The term "thermally stable" refers to a water-soluble polymer composition having a decomposition temperature greater than 275 °C (by thermogravimetric analysis) and a modulus greater than 1×10 6 Pa at a build chamber temperature equal to or higher than 180 °C and below the thermal decomposition temperature of the water-soluble polymer or the reinforcing filler.

[0045] The term "thermally stable water-soluble polymer composition" refers to a composition comprising at least one water-soluble polymer and at least one reinforcing filler, and may optionally include fillers, stabilizers, or additives.

[0046] The term "water-soluble" refers to a material that absorbs, swells, dissolves, disintegrates, or deteriorates in the presence of water.

[0047] The recitation of a numerical range using endpoints includes all numbers included within that range (e.g., 1 to 5 includes 1, 1.5, 3, 3.95, 4.2, 5, etc.).

[0048] The thermally stable water-soluble polymer composition of the present disclosure comprises at least one water-soluble polymer and at least one reinforcing filler. In another embodiment, the thermally stable water-soluble polymer composition employs various additives that can enhance solubility, adhesion to construction materials, thermal stability, mechanical properties, and other desired properties.

[0049] Various water-soluble polymers can be employed in the thermally stable water-soluble polymer composition. Non-limiting examples of water-soluble polymers include coagulants such as quaternary polyamines, sulfonated polyesters, sulfonated polyester salts, poly(diallyldimethylammonium chloride) (polyDADMAC), and dicyandiamide resins; flocculants and polymeric surfactants such as nonionic, anionic, and cationic materials; amphoteric polymers; polyethyleneimine; polyamide-amine; polyamine-based polymers; polyethylene oxide; sulfonated compounds; polyvinylpyrrolidone; polylactic acid; polycaprolactone; polyacrylate-based dispersants; polyvinyl alcohol; butylene glycol vinyl alcohol copolymers; cellulose derivatives; and copolymers or combinations thereof.

[0050] Non-limiting examples of water-soluble polymers useful in the present disclosure include sulfonated polyester salts sold by Eastman Chemical Company as AQ TM resins. Non-limiting examples of water-soluble copolymers include copolymers of polyvinyl alcohol (PVOH), including polyvinyl alcohol-copoly-vinylpyrrolidone (PVOH-co-PVP), polyvinyl alcohol-copoly-vinylamine, polyvinyl alcohol-copoly-vinyl acetate, polyvinyl alcohol-copoly-butylene glycol vinyl alcohol, polyvinyl alcohol-copoly-vinyl acetate, polyvinyl alcohol-copoly-polyacrylate, and polyvinyl alcohol-copoly-polymethacrylate. Non-limiting examples of commercially available water-soluble copolymers include PVOH-co-PVP sold by Seikisui Corporation as ULTILOC 4005 TM ; BVOH sold by Nippon Goshei as NICHIGO G-POLYMER TM ; and AQUAZOL sold by Polymer Chemistry Innovations as TMPoly-2-ethyl oxazoline for sale; and by The Dow Chemical Company as AFFINISOL TM Hydroxypropyl methyl cellulose for sale.

[0051] A variety of reinforcing fillers can be employed in the thermally stable water-soluble polymer composition. The reinforcing fillers can impart certain physical properties, including but not limited to increasing the viscosity or modulus of the material at high temperatures. Non-limiting examples of reinforcing fillers useful in the present disclosure include nanomaterials having a diameter of less than 200 nm and an aspect ratio greater than 10:1. Non-limiting examples of nanomaterials useful in the present disclosure include single-walled carbon nanotubes, multi-walled carbon nanotubes, functionalized carbon nanotubes, boron nitride nanotubes, ceramic nanotubes, ceramic nanorods, metal nanowires, metal oxide nanowires, metal oxide nanorods, inorganic nanowires, inorganic nanorods, polymer nanofibers, fibrous mineral substances, cellulose fibrils, and the like. In other embodiments, the reinforcing filler includes carbon nanotubes, such as carbon nanotubes commercially manufactured by Nanocyl, Inc. and sold commercially at the NC7000 grade.

[0052] Water-soluble polymers and reinforcing fillers at various loading levels can be employed in the thermally stable water-soluble polymer composition. In some embodiments, the thermally stable water-soluble polymer composition can include, for example, at least about 80 wt% of the water-soluble polymer, or at least about 85 wt% of the water-soluble polymer, or at least about 90 wt% of the water-soluble polymer, or at least about 99.5 wt% of the water-soluble polymer. In some embodiments, the thermally stable water-soluble polymer composition can include, for example, 0.5 wt% to 20 wt% of the reinforcing filler. In some embodiments, the thermally stable water-soluble polymer composition can contain at least about 0.5 wt% of the reinforcing filler, or at least about 1 wt% of the reinforcing filler, or at least about 2 wt% of the reinforcing filler, or at least about 5 wt% of the reinforcing filler, or at least about 10 wt% of the reinforcing filler, and up to about 20 wt% of the reinforcing filler. In another embodiment, the thermally stable water-soluble polymer composition contains 0.5 wt% to 20 wt% of the reinforcing filler. In yet another embodiment, the thermally stable water-soluble polymer composition contains 1 wt% to 10 wt% of the reinforcing filler.

[0053] The heat-stable water-soluble polymer composition of the present disclosure may include additives to impart additional functionality. Non-limiting examples of suitable additives include stabilizers, carbohydrates, light stabilizers, antioxidants, secondary antioxidants, fibers, blowing agents, blowing additives, antiblocking agents, heat-reflective materials, heat stabilizers, impact modifiers, biocides, antimicrobial additives, compatibilizers, plasticizers, tackifiers, processing aids, lubricants, slip agents, coupling agents, heat conductors, electrical conductors, catalysts, flame retardants, oxygen scavengers, fluorescent tags, fillers, minerals, metals, and colorants. The additives may be incorporated into the heat-stable water-soluble polymer composition as powders, liquids, pellets, granules, or in any other melt-processable form. The amounts and types of conventional additives in the heat-stable water-soluble polymer composition may vary depending on the polymer matrix and the desired properties of the final composition. Given the present disclosure, one of ordinary skill in the art will recognize that the additives and their amounts may be selected to achieve the desired properties in the final material. For example, typical additive loading levels may be from about 0.01 to 20 weight percent of the composition formulation. Suitable carbohydrate additives include, for example, those disclosed in U.S. Patent No. 10,435,576, which is incorporated herein by reference in its entirety.

[0054] In one embodiment, a stabilizer is added to the heat-stable water-soluble polymer composition to help further improve the thermal stability of the heat-stable water-soluble polymer composition. The stabilizer is typically selected by one of ordinary skill in the art based on the specific heat-stable water-soluble polymer composition. Non-limiting examples of stabilizers useful for the present disclosure include phosphites, polyaromatic phosphites, inorganic phosphates, hindered phenols, or thioesters. In other embodiments, Hostanox P-EPQ (e.g., the reaction product of phosphorus trichloride with 1,1'-biphenyl and 2,4-bis(1,1-dimethylethyl)phenol) or ADK STAB PEP-36 (e.g., [2,2-bis[(2,6-di-tert-butyl-4-methylphenoxy)methyl]-3-dihydroxyphosphinyloxypropyl] dihydrogen phosphite) are useful stabilizers for the heat-stable water-soluble polymer composition. For example, typical stabilizer loading levels may be from about 0.01 to 10 weight percent of the heat-stable water-soluble polymer composition.

[0055] In another embodiment, fillers are added to the heat-stable water-soluble polymer composition. Fillers are useful because they allow those skilled in the art to adjust the mechanical properties of end-use articles made from polymeric materials. Fillers can serve to improve the mechanical and thermal properties of polymeric materials. Fillers can also be used to reduce the coefficient of linear thermal expansion (CLTE) of polymeric articles. Non-limiting examples of fillers are mineral and organic fillers, including carbonates / esters, silicates / esters, talc, mica, wollastonite, clay, silica, alumina, carbon fibers, carbon black, carbon nanotubes, graphite, graphene, pozzolans, expanded pozzolans, perlite, glass fibers, solid glass microspheres, hollow glass microspheres, hollow spheres, ceramics, and conventional cellulosic materials, including: wood flour, wood fibers, sawdust, wood chips, newsprint, paper, linen, hemp, wheat straw, rice husks, kenaf, jute, sisal, peanut hulls, soybean hulls, or any cellulosic-containing material. The amount of filler in the heat-stable water-soluble polymer composition after melt processing is typically from 1 to 60 wt%. In another embodiment, the filler loading level is from 1 to 50 wt%. In yet another embodiment, the filler loading level is from 1 to 30 wt%.

[0056] The heat-stable water-soluble polymer composition can be prepared by mixing, processing, or a combination thereof. Depending on the water-soluble polymer matrix selected, this can be accomplished using various mixing methods known to those skilled in the art in view of the present disclosure. The water-soluble polymer, reinforcing filler, and any optional additives can be combined, for example, by a compounding mill, Banbury mixer, or a mixing extruder. In another embodiment, a vented twin-screw extruder is used. The materials can be used in the form of, for example, powders, pellets, liquids, or particulate products. The mixing operation is most conveniently carried out at a temperature above the melt processing temperature of the water-soluble polymer or the reinforcing filler, or above the melt processing temperatures of both the water-soluble polymer and the reinforcing filler. The resulting melt-processed heat-stable water-soluble polymer composition can be directly extruded into the form of a final product shape, or it can be pelletized or fed from the melt processing equipment to a secondary operation to pelletize the composition (e.g., using a pelletizer or densifier) for later use. In another embodiment, the heat-stable water-soluble polymer composition and additives can be directly 3D printed.

[0057] The heat-stable water-soluble polymer composition can be further processed for use in desired end-use applications. The heat-stable water-soluble polymer composition can be used as a feedstock in fused deposition modeling (FDM). In some embodiments, the feedstock can be a filament, although other feedstocks (e.g., films, sheets, shaped profiles, powders, pellets, etc.) can also be used. For FDM feedstocks, it is desirable to have an appropriate balance of stiffness and toughness. This is because when processed using an FDM-based 3D printer, the material must function properly. If the material is too soft, it has a tendency to bend when the drive system attempts to push the filament into or pull the filament out of the filament extruder head or liquefier. If the filament is not tough enough, it has a tendency to break or deform as it travels through the path to the filament extruder head. Those skilled in the art will recognize that the FDM filament composition should be designed to have an appropriate balance of stiffness and toughness in order to work with an FDM-type printer.

[0058] In additive manufacturing, it is well known that printing semi-crystalline and crystalline polymers can be challenging because they have a tendency to shrink in the build chamber when allowed to relax. This can lead to warping and curling of parts of the build material. Therefore, a build chamber temperature above the glass transition temperature of the build material is typically required to prevent part warping. Surprisingly, the heat-stable water-soluble polymer composition of the present disclosure can result in printed parts having low warping. This may be due in part to the excellent adhesion of the heat-stable water-soluble polymer composition to various build materials and build plates. The heat-stable water-soluble polymer composition can also exhibit significant adhesion properties to a wide range of build plates and build materials, including: polyamides (e.g., nylon 6, nylon 6.6, nylon 12), polyimides (e.g., Kapton), polyether-imides (PEI) (as shown in Figure 3 302), polyetherketoneketone (PEKK) (as shown in Figure 4 402), polyetheretherketone (PEEK) (as shown in Figure 5 502 and as shown in Figure 6 602), acrylonitrile-butadiene-styrene (ABS), polylactic acid (PLA), polyacrylic acid (e.g., PMMA), polycarbonate (PC), glass, metal, and so on.

[0059] The heat-stable water-soluble polymer composition can be used as a building material in additive manufacturing or as a support material to produce a water-soluble support. The heat-stable water-soluble polymer composition can also be converted into an article using conventional melt processing techniques (such as compounding, extrusion, molding, and casting) or other additive manufacturing processes. For use in an additive manufacturing process, various additive manufacturing devices can employ the heat-stable water-soluble polymer composition (as, for example, a water-soluble support or building material). Non-limiting examples of such additive manufacturing devices include, but are not limited to, the Dremel DigiLab 3D45 3D printer, LulzBot Mini 3D printer, MakerBot Replicator+, XYZprinting da Vinci Mini, Ultimaker 3, Flashforge Finder 3D printer, Robo 3D R1+Plus, Ultimaker 2+, Ultimaker S5, Titan Atlas, Arburg Freeformer 300X, Tumaker Bigfoot350Pro Dual, Intamsys 610, and AON M2.

[0060] The heat-stable water-soluble polymer composition can be selectively removed manually, automatically (e.g., computer-controlled dissolution), or by some combination thereof (e.g., by dissolution or mechanically) as a building or support material. For example, the heat-stable water-soluble polymer composition can dissolve or disintegrate upon exposure to water, making them easy to remove from three-dimensional components produced using the heat-stable water-soluble polymer composition and a building material. A variety of additives (such as those already disclosed above) can be added to the heat-stable water-soluble polymer composition to form an article.

[0061] In one embodiment, a method of producing a heat-stable water-soluble support includes melt processing at least one water-soluble polymer and at least one reinforcing filler, converting the heat-stable water-soluble polymer composition into 3D printing feedstock, and 3D printing the heat-stable water-soluble polymer composition to form a water-soluble support or building material, as Figure 1 shown in 102 of

[0062] The heat-stable water-soluble polymer composition can offer many advantages. For example, the heat-stable water-soluble polymer composition can be at least about 180 °C, or at least about 200 °C (as Figure 2It is substantially stable at a build chamber temperature of about 202 °C, or at least about 220 °C, or at least about 240 °C, or at least about 260 °C, or at least about 280 °C and at most about 300 °C. When the heat-stable water-soluble polymer composition is used to form a water-soluble support, the water-soluble support is also substantially stable at a build chamber temperature of 180 °C, or at least about 200 °C, or at least about 220 °C, or at least about 240 °C, or at least about 260 °C, or at least about 280 °C and at most about 300 °C, and is also substantially dry at a build chamber temperature of at least about 180 °C.

[0063] Heat-stable water-soluble polymer compositions and articles comprising such compositions have a wide range of uses in many industries, including but not limited to additive manufacturing. These compositions and articles can provide significant value to plastic compounders and converters. The disclosed compositions and articles provide enhanced solubility and adhesion to a wide range of thermoplastic polymers, tunable rheological properties, and increased modulus at higher temperatures. Non-limiting examples of articles produced from such compositions include, but are not limited to; buffers, textiles, medical supplies, automotive components, filters, separators, armor, insulation materials, agricultural films, building materials, aerospace components, and soluble supports.

[0064] In the following examples, all parts and percentages are by weight unless otherwise indicated.

[0065] Examples

[0066] Table 1: Materials

[0067]

[0068] Table 2: Experimental Formulations

[0069]

[0070]

[0071] Sample Preparation: Formulations 1-22

[0072] Prepare each of Formulations 1 - 22 according to the weight ratios in Table 2. Meter the Formulations 1 - 22 by weight into a 27 mm twin - screw extruder (52:1 L:D, purchased from Entek, Lebanon, Oregon, United States) using separate feeders. The compounding of Formulations 1 - 18 was carried out using the following temperature profile: namely, at 50 to 95°F in Zone 1; at 100 to 135°F in Zone 2; at 200 to 215°F in Zone 3; at 330 to 400°F in Zone 4; at 400 to 450°F in Zones 5 to 13; and the die temperature was 430°F. The screw speed of the extruder was approximately 300 rpm and the output rate was approximately 30 lbs / hr. The die pressure was recorded at 250 to 500 psi and the extruder torque readings ranged from 68 to 74%. The compounded mixture was extruded onto an air - cooled belt conveyor and pelletized into cylindrical pellets of approximately 2.5 mm × 2.5 mm using a pelletizer of Bullet model 62 purchased from Maag Group, Oberglatt, Switzerland, and collected in aluminized bags.

[0073] Filament Preparation: Formulation 4

[0074] Using a 1.75″ single - screw extruder commercially available from Davis - Standard, Pawcatuck, Connecticut, USA, the sample 4 pellets were converted into filaments of two standard diameters, 1.75 mm and 2.85 mm, for FDM 3D printing. The single - screw extruder was equipped with a breaker plate, a screen pack (40 / 60 / 80 mesh), and a 2:1 barrier Maddock screw. For manufacturing 1.75 mm filaments, a temperature profile of 230°C in Zone 1, 232°C in Zone 2, 238°C in Zone 3, 236°C in Zone 4 and a die temperature of 234°C, as well as a screw speed of approximately 10.7 rpm and an output rate of approximately 36 m / min were used. For manufacturing 2.85 mm filaments, a temperature profile of 230°C in Zone 1, 232°C in Zone 2, 238°C in Zone 3, 236°C in Zone 4 and a die temperature of 234°C, as well as a screw speed of approximately 19.6 rpm and an output rate of approximately 20 m / min were used. The filaments were extruded through a circular die, air - cooled, and wound onto spools with 3″ cores.

[0075] Dissolution Method Test 1: Formulations 1 - 22

[0076] For each of Formulations 1 - 22, solubility was evaluated on a DISTEK 2500 Dissolution Tester (commercially available from Distek, Inc., North Brunswick, NJ) using the following procedure. At approximately 80 °C, 5 grams of the sample in pellet form was placed in approximately 400 mL of tap water with a constant stirring rate of 350 rpm. The dissolution time was reported when the sample was completely solubilized such that no observable precipitate remained at the bottom of the dissolution vessel. The results are provided in Table 3.

[0077] Table 3: Results of Dissolution Method Test 1

[0078]

[0079]

[0080] Annealing Method Test 1: Formulations 1 - 22

[0081] For each of Formulations 1 - 22, approximately 2 grams of the sample in pellet form was placed on a watch glass in a convection oven at 210 °C under an air atmosphere for 24 hours. Parallel samples of the same formulation were run for 48 hours. The samples were removed from the oven, allowed to cool to room temperature, and solubility was evaluated using Dissolution Method Test 2 (below). The results are provided in Table 4.

[0082] Table 4: Results of Dissolution Method Test 2 (Annealed Formulations 1 - 22)

[0083]

[0084]

[0085] Dissolution Method Test 2: Formulations 1 - 22 (Annealed Samples)

[0086] For each of Formulations 1 - 22 annealed using Annealing Method Test 1 (above), the samples were removed from the oven and cooled to room temperature. Since the samples adhered to the watch glass, the entire watch glass was subjected to the dissolution procedure. The watch glass and sample were placed in approximately 400 mL of tap water at approximately 80 °C and stirred at a constant stirring rate of 100 rpm. The dissolution time was reported when the sample was completely disintegrated such that no observable material remained on the watch glass at the bottom of the dissolution vessel. The results are provided in Table 4.

[0087] Annealing Method Test 2: Formulations 18–22

[0088] For each of Formulations 18 - 22, approximately 2 grams of the sample in pellet form was placed on a watch glass in a convection oven at 210 °C under an air atmosphere. The samples were monitored and imaged initially (time = 0) and after 24 hours of exposure. The results are provided in Table 5.Figure 7 Images of each formulation and their resulting appearances are shown. 702 is formulation 18 in pellet form. 704 is the resulting appearance of formulation 18. 706 is formulation 19 in pellet form. 708 is the resulting appearance of formulation 19. 710 is formulation 20 in pellet form. 712 is the resulting appearance of formulation 20. 714 is formulation 21 in pellet form. 716 is the resulting appearance of formulation 21. 718 is formulation 22 in pellet form. 720 is the resulting appearance of formulation 21.

[0089] Table 5: Observation Results of Annealing Method Test 2 (Formulations 18–22)

[0090]

[0091]

[0092] Capillary Rheology Characterization

[0093] Capillary rheological analysis was performed on formulations 1-5 and 18 using a capillary rheometer (purchased from Dynisco, Franklin, Massachusetts). All formulations were analyzed using a conical die at 250 °C. The formulations were analyzed at variable shear rates from 100 and 30,0000 s -1 . The results of this characterization are shown in Table 6, particularly the apparent viscosities at low shear (200 s -1 ) and high shear (10,500 s -1 ).

[0094] Table 6: Apparent Viscosity Results for Formulations 1-5 and 18

[0095]

[0096] Torsional Dynamic Mechanical Analysis Characterization

[0097] Torsional dynamic mechanical analysis (DMA) was performed on injection molded test parts of formulations 1-5, 8, and 18 using an Anton-Paar MCR702 (commercially available from Anton-Paar, Graz, Austria). The molded samples were analyzed by DMA in the temperature range of 20 °C - 300 °C. The results of this characterization are shown in Table 7, particularly the storage modulus at specific temperatures.

[0098] Table 7: Torsional Storage Modulus in Temperature Results of Dynamic Mechanical Analysis for Formulations 1-5, 8, 18

[0099]

[0100] To show that the modulus is not an artifact of molding, samples of formulation 4 were printed on an Arburg Freeformer 300X and characterized by DMA using the method described previously.

[0101] Table 8 shows the results of this characterization, specifically the storage modulus at specific temperatures.

[0102] Table 8: Torsional storage modulus of dynamic mechanical analysis at temperature results, formulation 4, molded parts vs. printed parts

[0103]

[0104] Having thus described specific embodiments, those skilled in the art will readily appreciate that the teachings found herein can be applied to other embodiments within the scope of the appended claims.

Claims

1. A thermally stable water-soluble polymer composition, comprising: at least one water-soluble polymer; and at least one reinforcing filler; wherein the composition is stable at printing temperatures up to 300 °C and build chamber temperatures greater than 180 °C, and remains soluble after exposure at 180 °C for 24 hours.

2. The thermally stable water-soluble polymer composition according to claim 1, wherein the water-soluble polymer is a sulfonate polyester salt.

3. The thermally stable water-soluble polymer composition according to claim 1, wherein the reinforcing filler is a carbon nanotube.

4. The thermally stable water-soluble polymer composition according to claim 1, further comprising one or more additives.

5. The thermally stable water-soluble polymer composition according to claim 4, wherein the additive is a stabilizer.

6. The thermally stable water-soluble polymer composition according to claim 5, wherein the stabilizer is a phosphite-based stabilizer.

7. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 180 °C.

8. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 200 °C.

9. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 220 °C.

10. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 240 °C.

11. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 260 °C.

12. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 300 °C.

13. The thermally stable water-soluble polymer composition according to claim 1, wherein the thermally stable water-soluble polymer forms a feedstock.

14. An article comprising the thermally stable water-soluble polymer composition according to claim 1.

15. A method, comprising: melt-processing at least one water-soluble polymer and at least one reinforcing filler to form a thermally stable water-soluble polymer composition; forming a feedstock from the thermally stable water-soluble polymer composition; and and 3D printing the feedstock to form a water-soluble support.

16. The method according to claim 15, wherein the step of 3D printing forms an article.

17. A water-soluble support, comprising: a thermally stable water-soluble polymer composition formed by melt-processing at least one water-soluble polymer and at least one reinforcing filler; wherein the water-soluble support is substantially dry and substantially stable at a build chamber temperature of at least about 180°C.

18. The water-soluble support according to claim 17, wherein the water-soluble support is substantially stable at a build chamber temperature of at least about 220°C.

19. The water-soluble support according to claim 17, wherein the water-soluble support is substantially stable at a build chamber temperature of at least about 260°C.

20. A three-dimensional printed article, comprising: a three-dimensional printed object, the three-dimensional printed object being generally deposited on a substantially horizontal build plate in a build chamber; and one or more water-soluble supports, the one or more water-soluble supports being positioned around one or more portions of the three-dimensional printed object and supporting the one or more portions of the three-dimensional printed object, the water-soluble support comprising a thermally stable water-soluble polymer composition; wherein the thermally stable water-soluble polymer composition is formed by melt processing at least one water-soluble polymer and at least one reinforcing filler.

21. The three-dimensional printed article according to claim 20, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 180°C.

22. The three-dimensional printed article according to claim 20, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 220°C.

23. The three-dimensional printed article according to claim 20, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 260°C.

24. The three-dimensional printed article according to claim 20, wherein the thermally stable water-soluble polymer composition is substantially stable at a build chamber temperature of at least about 300°C.

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