THERMALLY STABLE WATER-SOLUBLE POLYMER COMPOSITION

Abstract

A thermally stable, water-soluble polymer composition includes at least one water-soluble polymer and at least one reinforcing filler. The thermally stable, water-soluble polymer composition includes at least one water-soluble polymer and at least one reinforcing filler, and can solve several additive manufacturing challenges. That is, such a composition can dissolve or disintegrate in water at a neutral pH, can be compatible with both hydrophilic and hydrophobic polymers, can be used as a support material for build chamber temperatures of at least about 180° C., and can exhibit a thermal stability of 1×10 at print chamber temperatures. 6 It has an elastic modulus of greater than 100 Pa and is easily removable (dissolves / disintegrates) after printing for at least 24 hours at this build chamber temperature, all of which may be desirable when 3D printing high-temperature engineering thermoplastics, for example.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 415,676, filed October 13, 2022, which is incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to compositions and methods for making and using thermally stable, water-soluble polymer compositions. [Background technology]

[0003] Additive manufacturing processes, commonly referred to as three-dimensional (3D) printing, can be used to build desired objects and are expected to find application in many industries (e.g., aerospace, automotive, medical, etc.). Examples of processes include, but are not limited to, binder jetting, electron beam melting (EBM), fused deposition modeling (FDM), filament fusion fabrication (FFF), direct extrusion, inkjet, layer-on-layer manufacturing (LOM), selective laser sintering (SLS), selective toner electrophotography (STEP), and stereolithography (SL). Using such processes, a desired object can be modeled in a computer-aided design (CAD) package and then printed using a selected build material. In deposition-based methods like FDM, the selected build material is typically extruded layer by layer by a heated printer under computer command. Printing with commercially available additive manufacturing devices, such as the ARBURG™ Freeformer system, often occurs in a build chamber that can provide heating and temperature control.

[0004] Many additive manufacturing techniques use support layers or structures to build the desired object. However, the limited availability of suitable support methods, materials, and structures limits 3D printing to certain design types. The most basic support method uses the same material for the support as for the printed object. This technique involves erecting supports similar to scaffolding on a building to "prop up" steep overhangs or spans. This type of support, known as "breakable" or "raft" support, can be effective but can be cumbersome, time-consuming, and difficult to remove by mechanical breaking or trimming. It is not uncommon to spend hours removing or cutting support material from a 3D-printed object using razor blades, scalpels, sandpaper, and even power tools. Using different support and print methods can also be problematic. For example, certain hydrophobic polymers (e.g., polypropylene) are nearly impossible to print due to the immiscibility of the support material with the base resin being 3D printed.

[0005] The inability to remove internal support materials can further limit the variety of object designs. Depending on the external geometry, removing internal support materials can be difficult, if not impossible. For years, many have attempted to solve this problem by using support structures that are thought to dissolve in extremely hot water, strong acidic or basic conditions, organic solvents, or various other chemicals. Such products are often cumbersome, even dangerous, and generally unsuccessful. Another challenge relates to creating support materials that are 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), polyphenylene sulfone (PPSU), and polyetherimide (PEI). Typically, such materials can require high melt temperatures (above 270°C) and high print chamber temperatures (above 180°C) for extended periods of time (more than 24 hours). The present disclosure provides thermally stable, water-soluble polymer compositions that perform well under these extreme conditions while maintaining sufficient dissolution / removal properties after printing is complete. Summary of the Invention

[0006] Thermally stable, water-soluble polymer compositions comprising at least one water-soluble polymer (e.g., sulfopolyester (SPE)) and at least one reinforcing filler (e.g., carbon nanotubes) can solve several additive manufacturing challenges, i.e., such compositions can dissolve or disintegrate in water at room temperature at neutral pH, can be compatible with both hydrophilic and hydrophobic polymers, can be used as support materials for build chamber temperatures of at least about 180°C, and have an elastic modulus of at least 1×10 at print chamber temperatures. 6 It exceeds 100 Pa and is easily removable (dissolves / disintegrates) after printing for at least 24 h at this build chamber temperature, all of which may be desirable when, for example, 3D printing high-temperature engineering thermoplastics.

[0007] Furthermore, thermally stable, water-soluble polymer compositions can be unique in that such compositions can provide improved mechanical properties, heat resistance, and functionality. Some embodiments have improved mechanical properties, including modulus, storage modulus (at elevated temperatures), impact strength, tensile strength, and coefficient of linear thermal expansion (CLTE), making the thermally stable, water-soluble polymer compositions suitable for 3D printing using filament-type printers. For example, melt processing of water-soluble polymers with reinforcing fillers can produce thermally stable, water-soluble polymer compositions with increased modulus at high print chamber temperatures, a desirable property for fused deposition modeling (FDM) and direct extrusion 3D printers.

[0008] In some embodiments, the thermally stable, water-soluble polymer composition comprises at least one water-soluble polymer and at least one reinforcing filler. The water-soluble polymer and reinforcing filler can be combined using conventional melt processing techniques, such as twin-screw extrusion.

[0009] In some embodiments, a three-dimensional printed article includes a three-dimensionally printed object generally deposited on a substantially horizontal build plate in a build chamber, and one or more soluble supports, comprising a water-soluble polymer blend composition, positioned around and supporting one or more portions of the three-dimensionally printed object. The thermally stable water-soluble polymer composition can be formed by melt processing of a water-soluble polymer and a reinforcing filler. The thermally stable water-soluble polymer composition can be substantially stable, for example, at build chamber temperatures of at least about 180°C. In other embodiments, the build material of the three-dimensionally printed article includes the thermally stable water-soluble polymer composition.

[0010] In some embodiments, the thermally stable water-soluble support is formed by melt processing of a water-soluble polymer and a reinforcing filler, and is substantially dry and substantially stable at build chamber temperatures of at least about 180°C.

[0011] The above summary is not intended to describe each disclosed embodiment or every implementation. The following detailed description more particularly exemplifies exemplary embodiments. [Brief explanation of the drawings]

[0012] [Figure 1] Figure 1 is an image of a heat stable water soluble polymer composition printed using an Arburg Freeformer 300X at a chamber temperature of 140°C. [Figure 2] Figure 2 is an image of a heat stable water soluble polymer composition printed using an Arburg Freeformer 300X at a chamber temperature of 200°C. [Figure 3] Figure 3 is an image of a thermally stable, water-soluble polymer composition printed in polyetherimide (PEI, ULTEM9085) using an Arburg Freeformer 300X at a chamber temperature of 185°C. [Figure 4] Figure 4 is an image of a heat-stable, water-soluble polymer composition printed in polyetherketoneketone (PEKK) using AON M2+ at a chamber temperature of 70°C. [Figure 5] Figure 5 is an image of a heat-stable water-soluble polymer composition printed in polyetheretherketone (PEEK) using an Arburg Freeformer 300X at a chamber temperature of 200°C. [Figure 6] FIG. 6 is an image of a thermally stable, water-soluble polymer composition printed on polyetheretherketone (PEEK) using AON M2+ at a chamber temperature of 65°C. [Figure 7] FIG. 7 shows the appearance of formulations 18-22 after 0 and 24 hours of annealing. DETAILED DESCRIPTION OF THE INVENTION

[0013] Detailed Description of the Invention Unless the context otherwise indicates, the following terms have the following meanings, which apply to both the singular and the plural:

[0014] The terms "a," "an," "the," "at least one," and "one or more" are used interchangeably. Thus, for example, a thermally stable, water-soluble polymer composition that includes "a" water-soluble polymer means that the thermally stable, water-soluble polymer composition can include "one or more" water-soluble polymers.

[0015] The terms "additive manufacturing," "three-dimensional printing," "3D printing," or "3D printed" refer to any process used to create 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, additive manufacturing (LOM), selective laser sintering (SLS), selective toner electrophotography (STEP), and stereolithography (SL)).

[0016] The term "build chamber" refers to a space, often enclosed, within or utilized by an additive manufacturing device in which a desired object can be printed. A non-limiting example of a build chamber can include the ARBURG™ Freeformer (commercially available from Arburg GmbH, Lossburg, Germany).

[0017] The term "build chamber temperature" refers to the temperature provided within the build chamber during additive manufacturing.

[0018] The term "build material" refers to the material that is printed in three dimensions using additive manufacturing processes to produce a desired object, often the material that remains after removal of a soluble support.

[0019] The term "build plate" refers to a substrate, often a removable film or sheet, onto which a build material or soluble support can be printed.

[0020] The term "composition" refers to a multi-component material.

[0021] The term "copolymer" refers to a polymer derived, either actually (e.g., by copolymerization) or conceptually, from more than one monomer species. For example, a copolymer derived from two monomer species may be called a bipolymer; a copolymer derived from three monomers may be called a terpolymer; and a copolymer derived from four monomers may be called a quatrapolymer. Copolymers can be characterized based on the arrangement of branches in their structure, such as, for example, linear copolymers and branched copolymers. Copolymers can also be characterized based on how the monomer units are arranged, such as, for example, alternating copolymers, periodic copolymers, statistical copolymers, graft copolymers, and block copolymers.

[0022] The term "crystalline" refers to a polymer composition having a crystallinity of greater than 90% as measured by differential scanning calorimetry (DSC) according to ASTM standard D3418-12, "Standard Test Method for Transition Temperatures and Enthalpies of Melting and Crystallization of Polymers by Differential Scanning Calorimetry."

[0023] The term "filler" refers to a material that is immiscible in the thermally stable, water-soluble polymer composition and that modifies the end-use properties.

[0024] The term "feedstock" refers to a form of material that can be utilized in an additive manufacturing process (e.g., as a build material or soluble support). Non-limiting examples of feedstock include pellets, powders, filaments, billets, liquids, sheets, molded profiles, etc.

[0025] The term "high temperature thermoplastic" refers to polymers or polymer compositions that are typically melt processed at temperatures above about 220° C. Non-limiting examples of high temperature thermoplastics include, but are not limited to, polycarbonate (PC), polyamide (nylon), polyester (PET), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyphenylene sulfone (PPSU), and polyetherimide (PEI).

[0026] The term "melt processing techniques" refers to techniques for applying heat and mechanical energy to reform, blend, mix, or otherwise reconfigure polymers or compositions, such as compounding, extrusion, injection molding, blow molding, rotational molding, or batch mixing. 3D printing processes, useful for printing thermoplastic and elastomeric melt-processable materials, are an example of a melt processing technique.

[0027] The term "mixing" means combining or bringing together to form one single substance, mass, phase, composite, dispersion, or more homogeneous state, which may include, but is not limited to, any physical blending method, extrusion technique, or melting method.

[0028] The term "monomer" refers to a molecule that can be polymerized to provide a structural unit in the basic structure of a polymer.

[0029] The terms "polymer" and "polymeric" refer to molecules of high relative molecular weight whose structure essentially comprises multiple repeating units derived, actually or conceptually, from molecules of lower relative molecular weight (monomers). The term "polymer" can also refer to "copolymers."

[0030] The term "reinforcing filler" refers to a material that is not viscoelastic under 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 of greater than 10:1.

[0031] The term "semi-crystalline" refers to a polymer composition having a crystallinity of greater than 5% but less than 90% as measured by differential scanning calorimetry (DSC) according to ASTM standard D3418-12, "Standard Test Method for Determining Transition Temperatures and Enthalpies of Melting and Crystallization of Polymers by Differential Scanning Calorimetry."

[0032] The terms "soluble support," "soluble support material," or "water-soluble support" refer to a material that is three-dimensionally printed using an additive manufacturing process to physically support or secure the build material during 3D printing, and that can be removed by chemical solvation or dissolution as desired during or after the additive manufacturing process.

[0033] The term "stabilizer" means one or more additives or materials that substantially enhance, whether actual or notional, the resistance of a polymer to degradative processes (mechanical, thermal, hydrolytic, acid / base, oxidative, free radical, ultraviolet or other forms of radiation).

[0034] The term "substantially dry" means that the material contains about 15% or less volatile material, or about 10% or less volatile material under standard conditions based on the weight of the heat stable, water soluble polymer composition.

[0035] The terms "substantially stable" or "substantially stable" refer to materials that exhibit dimensional stability (e.g., minimal flow, melting, or deformation) at most printing process temperatures (e.g., build chamber temperatures).

[0036] The term "thermally stable" means having a decomposition temperature (by thermogravimetric analysis) above 275°C and a thermal decomposition temperature of 1x10 at a build chamber temperature above 180°C and below the thermal decomposition temperature of the water-soluble polymer or reinforcing filler. 6 It refers to a water-soluble polymer composition having a modulus of elasticity greater than Pa.

[0037] 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.

[0038] The term "water-soluble" refers to a material that absorbs, swells, dissolves, disintegrates, or deteriorates in the presence of water.

[0039] The recitation of numerical ranges using endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 3, 3.95, 4.2, 5, etc.).

[0040] The thermally stable, water-soluble polymer compositions of the present disclosure include at least one water-soluble polymer and at least one reinforcing filler. In another embodiment, the thermally stable, water-soluble polymer compositions employ various additives that can enhance solubility, adhesion to build materials, thermal stability, mechanical properties, and other desirable properties.

[0041] A variety of water-soluble polymers can be used in the thermally stable water-soluble polymer composition. Non-limiting examples of water-soluble polymers include coagulants such as quaternary polyamines, sulfopolyesters, sulfopolyester salts, polydiallylammonium chloride (polyDADMAC), and dicyandiamide resins; flocculants and polymeric surfactants such as nonionic, anionic, and cationic materials; amphoteric polymers; polyethyleneimine; polyamido-amines; polyamine-based polymers; polyethylene oxide; sulfonated compounds; polyvinylpyrrolidone; polylactic acid; polylactones; polyacrylate-type dispersants; polyvinyl alcohol; butanediol-vinyl alcohol copolymers; cellulose derivatives; and copolymers or combinations thereof.

[0042] Non-limiting examples of water-soluble polymers useful in the present disclosure include sulfopolyester salts sold by Eastman as AQ™ resins. Non-limiting examples of water-soluble copolymers include copolymers of polyvinyl alcohol (PVOH), including polyvinyl alcohol-co-vinylpyrrolidinone (PVOH-co-PVP), polyvinyl alcohol-co-vinylamine, polyvinyl alcohol-co-vinyl acetate, polyvinyl alcohol-co-butenediol vinyl alcohol, polyvinyl alcohol-co-vinyl acetate, polyvinyl alcohol-co-polyacrylate, and polyvinyl alcohol-co-polymethacrylate. Non-limiting examples of commercially available water-soluble copolymers include PVOH-co-PVP sold by Seikisui Corporation as ULTILOC4005™; BVOH sold by Nippon Goshei as NICHIGO G-POLYMER™; poly-2-ethyloxazoline sold by Polymer Chemistry Innovations, Inc. as AQUAZOL™; and hydroxypropyl methylcellulose sold by Dow Chemical Co. as AFFINISOL™.

[0043] Various reinforcing fillers can be employed in the thermally stable, water-soluble polymer composition. Reinforcing fillers can impart certain physical properties, including, but not limited to, increasing the viscosity or modulus of the material at elevated temperatures. Non-limiting examples of reinforcing fillers useful in the present disclosure include nanomaterials having diameters less than 200 nm and aspect ratios less 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 species, cellulosic fibrils, and the like. In other embodiments, reinforcing fillers include carbon nanotubes, such as those commercially produced by Nanocyl, Inc. and sold as grade NC7000.

[0044] Various loading levels of water-soluble polymer and reinforcing filler can be used in the thermally stable, water-soluble polymer composition. In some embodiments, the thermally stable, water-soluble polymer composition may comprise, for example, at least about 80 wt. % water-soluble polymer, or at least about 85 wt. % water-soluble polymer, or at least about 90 wt. % water-soluble polymer, or at least about 99.5 wt. % water-soluble polymer. In some embodiments, the thermally stable, water-soluble polymer composition may comprise, for example, 0.5 to 20 wt. % reinforcing filler. In some embodiments, the thermally stable, water-soluble polymer composition may comprise at least about 0.5 wt. % reinforcing filler, or at least about 1 wt. % reinforcing filler, or at least about 2 wt. % reinforcing filler, or at least about 5 wt. % reinforcing filler, or at least about 10 wt. % reinforcing filler, and up to about 20 wt. % reinforcing filler. In another embodiment, the thermally stable, water-soluble polymer composition comprises 0.5 to 20 wt. % reinforcing filler. In yet another embodiment, the thermally stable, water-soluble polymer composition comprises 1 to 10 wt. % reinforcing filler.

[0045] The heat-stable, water-soluble polymer composition of the present disclosure may contain additives to impart additional functionality. Non-limiting examples of suitable additives include stabilizers, carbohydrates, light stabilizers, antioxidants, secondary antioxidants, fibers, blowing agents, foaming additives, antiblocking agents, heat reflectors, thermal stabilizers, impact modifiers, biocides, antimicrobial additives, compatibilizers, plasticizers, tackifiers, processing aids, lubricants, slip agents, coupling agents, thermal conductors, electrical conductors, catalysts, flame retardants, oxygen scavengers, fluorescent tags, fillers, minerals, metals, and colorants. Additives can be incorporated into the heat-stable, water-soluble polymer composition as powders, liquids, pellets, granules, or other melt-processable forms. The amount and type of conventional additives in the heat-stable, water-soluble polymer composition can vary depending on the polymer matrix and the desired properties of the final composition. In light of this disclosure, one skilled in the art will understand that additives and their amounts can be selected to achieve desired properties in the final material. Typical additive loading levels can be, for example, about 0.01 to 20% by weight of the composition. Suitable carbohydrate additives include, for example, those disclosed in US Pat. No. 10,435,576, which is incorporated herein by reference in its entirety.

[0046] In one embodiment, a stabilizer is added to the thermally stable, water-soluble polymer composition to further improve its thermal stability. The stabilizer is typically selected by one skilled in the art depending on the particular thermally stable, water-soluble polymer composition. Non-limiting examples of stabilizers useful in the present disclosure include phosphites, polyaromatic phosphites, inorganic phosphates, hindered phenols, or thioesters. In another embodiment, Hostanox P-EPQ (e.g., phosphorus trichloride reaction product with 1,1'-biphenyl and 2,4-bis(1,1-dimethylethyl)phenol) or ADK STAB PEP-36 (e.g., dihydrogen phosphite [2,2-bis[(2,6-ditert-butyl-4-methylphenoxy)methyl]-3-dihydroxyphosphanyloxypropyl]) are useful stabilizers for the thermally stable, water-soluble polymer composition. Typical stabilizer loading levels may be, for example, about 0.01 to 10 wt. % of the thermally stable, water-soluble polymer composition.

[0047] In another embodiment, fillers are added to the heat-stable, water-soluble polymer composition. Fillers are useful in that they allow those skilled in the art to adjust the mechanical properties of the final product made using the polymer material. Fillers can function to improve the mechanical and thermal properties of the polymer material. Fillers can also be used to reduce the coefficient of linear thermal expansion (CLTE) of the polymer article. Non-limiting examples of fillers include mineral and organic fillers, including carbonates, silicates, talc, mica, wollastonite, clay, silica, alumina, carbon fiber, carbon black, carbon nanotubes, graphite, graphene, volcanic ash, expanded volcanic ash, perlite, glass fiber, solid glass microspheres, hollow glass microspheres, cenospheres, and ceramics, as well as conventional cellulosic materials, including wood flour, wood fiber, sawdust, wood chips, newsprint, paper, flax, hemp, wheat straw, rice husks, kenaf, jute, sisal, peanut shells, soybean hulls, or any cellulose-containing material. The amount of filler in the thermally stable, water-soluble polymer composition after melt processing is typically 1 to 60 wt%. In another embodiment, the filler loading level is 1 to 50 wt%. In yet another embodiment, the filler loading level is 1 to 30 wt%.

[0048] The thermally stable, water-soluble polymer composition can be prepared by mixing, processing, or a combination thereof. This can be done using a variety of mixing processes known to those skilled in the art in light of the present disclosure, depending on the water-soluble polymer matrix selected. The water-soluble polymer, reinforcing filler, and optional additives can be combined, for example, in a compounding mill, Banbury mixer, or mixing extruder. In another embodiment, a vented twin-screw extruder is utilized. The materials can be used in the form of, for example, a powder, pellet, liquid, or granular product. The mixing operation is most conveniently performed at a temperature above the melt processing temperature of the water-soluble polymer or reinforcing filler, or above the melt processing temperatures of both the water-soluble polymer and the reinforcing filler. The resulting melt-processed, thermally stable, water-soluble polymer composition can be directly extruded into the shape of the final product, or pelletized, or fed from the melt processing equipment to a secondary operation (e.g., using a pellet mill or densifier) ​​to pelletize the composition for later use. In another embodiment, the thermally stable, water-soluble polymer composition and additives can be directly 3D printed.

[0049] The thermally stable, water-soluble polymer composition can be further processed for a desired end use. The thermally 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, molded profiles, powders, pellets, etc.) can also be used. For FDM feedstock, a proper balance of stiffness and toughness is desirable because the material must function properly when processed using an FDM-based 3D printer. If the material is too flexible, it will tend to bend when the drive system attempts to push or pull the filament into the extruder head or liquefier. If the filament is not sufficiently rigid, it will tend to break or deform as it passes through the filament extruder head. Those skilled in the art will understand that FDM filament compositions must be designed to have the proper balance of stiffness and toughness to function in FDM-type printers.

[0050] It is well known that in additive manufacturing, semi-crystalline and crystalline polymers can be difficult to print because they tend to shrink in the build chamber when relaxed. This can result in part warping and curling of the build material. Therefore, build chamber temperatures above the glass transition temperature of the build material are typically required to prevent part warping. Surprisingly, the thermally stable, water-soluble polymer composition of the present disclosure can enable printed parts with reduced warpage. This may be due in part to the excellent adhesion of the thermally stable, water-soluble polymer composition to various build materials and build plates. The thermally stable, water-soluble polymer composition may also exhibit excellent adhesion properties to a wide range of build plate and modeling materials, such as polyamides (e.g., nylon 6, nylon 6.6, nylon 12), polyimides (e.g., Kapton), polyetherimide (PEI), shown as 302 in FIG. 3, polyetherketoneketone (PEKK), shown as 402 in FIG. 4, polyetheretherketone (PEEK), shown as 502 in FIG. 5 and as 602 in FIG. 6, polyacrylonitrile-butadiene-styrene (ABS), polylactic acid (PLA), polyacrylic (e.g., PMMA), polycarbonate (PC), glass, and metal.

[0051] The heat-stable, water-soluble polymer composition can be used as a build material or support material in additive manufacturing to create 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, casting, or other additive manufacturing processes. For use in additive manufacturing processes, various additive manufacturing devices can use the heat-stable, water-soluble polymer composition, for example, as a water-soluble support or build material. Non-limiting examples of 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 Bigfoot 350 Pro Dual, Intamsys 610, and AON M2.

[0052] The thermally stable, water-soluble polymer composition can be selectively removed as either the build material or the support material manually (e.g., by dissolution or mechanically), automatically (e.g., computer-controlled dissolution), or a combination thereof. For example, the thermally stable, water-soluble polymer composition can be dissolved or disintegrated when exposed to water, allowing for easy removal from three-dimensional parts fabricated using the thermally stable, water-soluble polymer composition and the build material. Various additives, such as those already disclosed above, can be added to the thermally stable, water-soluble polymer composition to form articles.

[0053] In one embodiment, a method for making a thermally stable, water-soluble support includes melt processing at least one water-soluble polymer and at least one reinforcing filler, converting the thermally stable, water-soluble polymer composition into a 3D printing feedstock, and 3D printing the thermally stable, water-soluble polymer composition to form a water-soluble support or build material, such as shown in FIG. 1 as 102.

[0054] Thermally stable, water-soluble polymer compositions can provide many advantages. For example, the thermally stable, water-soluble polymer composition can be substantially stable at build chamber temperatures of at least about 180°C, or at least about 200°C, as shown at 202 in Figure 2, 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 up to about 300°C. When the thermally stable, water-soluble polymer composition is used to form a water-soluble support, the water-soluble support is also substantially stable at build chamber temperatures 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 up to about 300°C, and is substantially dry at build chamber temperatures of at least about 180°C.

[0055] Thermally stable, water-soluble polymer compositions and articles comprising such compositions have broad utility 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 offer improved solubility and adhesion to a wide range of thermoplastic polymers, tunable rheological properties, and increased modulus at higher temperatures. Non-limiting examples of articles made from such compositions include, but are not limited to, cushioning, textiles, medical supplies, automotive parts, filters, separators, armor, insulation, agricultural films, building materials, aerospace components, and soluble supports.

[0056] In the following examples, all parts and percentages are by weight unless otherwise specified.

[0057] Example

[0058] Table 1: Materials

[0059] [Table 1] Table 2: Experimental formulations

[0060] [Table 2] Sample Preparation: Formulations 1-22

[0061] Compounds 1-22 were each prepared according to the weight ratios in Table 2. Compounds 1-22 were gravimetrically fed into a 27 mm twin-screw extruder (L:D = 52:1, commercially available from Entek, Lebanon, Oregon, USA) using separate feeders. Compounds 1-18 were compounded using the following temperature profiles: 50-95°F in Zone 1; 100-135°F in Zone 2; 200-215°F in Zone 3; 330-400°F in Zone 4; 400-450°F in Zones 5-13; and a die temperature of 430°F. The extruder screw speed was approximately 300 rpm, and the output rate was approximately 30 lbs / hr. Die pressures were recorded at 250-500 psi, and extruder torque readings ranged from 68-74%. The composite mixture was extruded onto an air-cooled belt conveyor and pelletized using a Bullet Model 62 pelletizer available from the Maag Group, Oberglatt, Switzerland, into cylindrical pellets of approximately 2.5 mm x 2.5 mm and collected in aluminized bags. Filament Preparation: Formulation 4

[0062] The pellets of Sample 4 were converted into filament for use in FDM 3D printing in two standard diameters, 1.75 mm and 2.85 mm, using a 1.75 inch single screw extruder commercially available from Davis-Standard, Inc., Pawcatuck, Connecticut, USA, equipped with a breaker plate, a screen pack (40 / 60 / 80 mesh), and a 2:1 barrier Maddock screw. To produce the 1.75 mm filament, 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 was used, along with a screw speed of approximately 10.7 rpm and an output speed of approximately 36 meters / min. To produce the 2.85 mm filament, 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 was used, along with a screw speed of about 19.6 rpm and an output speed of about 20 meters / min. The filament was extruded through a circular die, air cooled, and wound onto a spool with a 3 inch core. Dissolution test 1: Compounds 1-22

[0063] Each of Formulations 1-22 was evaluated for solubility in a DISTEK 2500 dissolution tester (commercially available from Distek, Inc., North Brunswick, New Jersey) using the following procedure: A 5-gram sample in pellet form was placed in approximately 400 mL of tap water at approximately 80°C with a constant stirring rate of 350 rpm. The dissolution time was reported when the sample was completely dissolved and no pellets were observable at the bottom of the dissolution vessel. The results are shown in Table 3.

[0064] Table 3: Dissolution Test 1 Results

[0065] [Table 3] Annealing Method Test 1: Formulations 1-22

[0066] For each of Formulations 1-22, approximately 2g samples in pellet form were placed on a watch glass in a convection oven at 210°C in air for 24 hours, while parallel samples of the same formulations were run for 48 hours. The samples were removed from the oven, cooled to room temperature, and evaluated for solubility using Dissolution Method Test 2 (below). The results are shown in Table 4.

[0067] Table 4: Dissolution Test 2 Results (Annealed Formulations 1-22)

[0068] [Table 4] Dissolution Test 2: Formulations 1-22 (Annealed Samples)

[0069] Each of Formulations 1-22, annealed using Annealing Method Test 1 (above), was removed from the oven and cooled to room temperature. Because the sample adhered to the watch glass, the entire watch was subjected to the dissolution procedure. The watch glass and sample were placed in approximately 400 mL of tap water at approximately 80°C with a constant stirring rate of 100 rpm. The dissolution time was reported when the sample was completely disintegrated and no observable lumps remained on the watch glass at the bottom of the dissolution vessel. The results are shown in Table 4. Annealing Test 2 Observations: Formulations 18-22

[0070] For each of Formulations 18-22, approximately 2 gram samples in pellet form were placed on a watch glass in a convection oven at 210°C under air. The samples were monitored and imaged initially (time = 0) and after 24 hours of exposure. The results are shown in Table 5. Figure 7 shows images of each formulation and its resulting appearance. 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.

[0071] Table 5: Annealing Method Test 2 Observation Results (Formulations 18-22)

[0072] [Table 5] Capillary rheological characterization

[0073] Capillary rheology analysis was performed on formulations 1-5 and 18 using a capillary rheometer (commercially available from Dynisco, Franklin, Massachusetts). All formulations were analyzed at 250°C using a cone die. The formulations were measured for 100 s -1 From 300,000s -1 The results of this characterization, specifically at low shear (200 s -1 ) and high shear (10,500s -1 ) shows the apparent viscosity under the conditions.

[0074] Table 6: Apparent Viscosity Results Formulations 1-5 and 18

[0075] [Table 6] Torsional dynamic mechanical analysis characterization

[0076] 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 over a temperature range of 20°C to 300°C. Table 7 shows the results of this characterization, specifically the storage modulus at specific temperatures.

[0077] Table 7: Dynamic Mechanical Analysis Torsional Storage Modulus Results at Temperature Compounds 1-5, 8, 18

[0078] [Table 7]

[0079] To demonstrate that the modulus was not due to molding, samples of Formulation 4 were printed in an Arburg Freeformer 300X and characterized by DMA using the method previously described. Table 8 shows the results of this characterization, specifically the storage modulus at specific temperatures.

[0080] Table 8: Dynamic Mechanical Analysis Torsional Storage Modulus Results with Temperature Formulation 4, Molded vs. Printed Parts [Table 8]

[0081] While particular embodiments have been described above, those skilled in the art will readily appreciate that the teachings described herein may be applied to still other embodiments within the scope of the claims appended hereto.

Claims

1. at least one water-soluble polymer; at least one reinforcing filler; Including, A thermally stable, water-soluble polymer composition that is stable at printing temperatures up to 300°C and build chamber temperatures above 180°C, and remains soluble even after exposure at 180°C for 24 hours.

2. The thermally stable, water-soluble polymer composition of claim 1 , wherein the water-soluble polymer is a sulfopolyester salt.

3. 10. The thermally stable, water-soluble polymer composition of claim 1, wherein said reinforcing filler is carbon nanotubes.

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

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

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

7. 10. The thermally stable, water-soluble polymer composition of claim 1, which is substantially stable at build chamber temperatures of at least about 180°C.

8. 10. The thermally stable, water-soluble polymer composition of claim 1, which is substantially stable at build chamber temperatures of at least about 200°C.

9. 10. The thermally stable, water-soluble polymer composition of claim 1, which is substantially stable at build chamber temperatures of at least about 220°C.

10. 10. The thermally stable, water-soluble polymer composition of claim 1, which is substantially stable at build chamber temperatures of at least about 240°C.

11. 10. The thermally stable, water-soluble polymer composition of claim 1, which is substantially stable at build chamber temperatures of at least about 260°C.

12. 10. The thermally stable, water-soluble polymer composition of claim 1, which is substantially stable at build chamber temperatures of at least about 300°C.

13. The thermally stable, water-soluble polymer composition of claim 1 forming a feedstock.

14. An article comprising the thermally stable, water-soluble polymer composition of claim 1.

15. 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 said thermally stable, water-soluble polymer composition; 3D printing the feedstock to form a water-soluble support.

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

17. 1. 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, The water-soluble support is substantially dry and substantially stable at build chamber temperatures of at least about 180°C.

18. 20. The water-soluble support of claim 17, which is substantially stable at build chamber temperatures of at least about 220°C.

19. 20. The water-soluble support of claim 17, which is substantially stable at build chamber temperatures of at least about 260°C.

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

21. 21. The three-dimensional printed object of 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. 21. The three-dimensional printed object of 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. 21. The three-dimensional printed object of 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. 21. The three-dimensional printed object of 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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