Polymer nanoparticle coated thermoplastic microparticles and methods of making and using same

Abstract

To provide particulate compositions suitable for additive manufacturing, and methods for production thereof.SOLUTION: A particulate composition comprises: a plurality of thermoplastic particulates comprising a thermoplastic polymer; and a plurality of polymer nanoparticles disposed upon an outer surface of the thermoplastic particulates, the polymer nanoparticles comprising a crosslinked fluorinated polymer. The crosslinked fluorinated polymer comprises a fluorinated (meth)acrylic monomer and a divinyl crosslinker.SELECTED DRAWING: None

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) Not applicable.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to additive manufacturing, and more particularly to additive manufacturing processes characterized by the consolidation of powder particulates coated with nanoparticles. [Background technology]

[0003] Additive manufacturing, also known as three-dimensional (3-D) printing, is a rapidly growing technology field. While additive manufacturing has traditionally been used for rapid prototyping tasks, this technology is increasingly being adopted to produce commercial and industrial parts (prints) of any number of complex shapes. The additive manufacturing process is carried out by the layer-by-layer deposition of either 1) molten printing material or a flow of a liquid precursor to the printing material, or 2) powder particles of the printing material. The layer-by-layer deposition is typically carried out under computer control to deposit and solidify the printing material in precise locations based on a digital three-dimensional computer-aided design model ("blueprint") of the part to be manufactured. Powder bed fusion (PBF) of powder particles is a particularly useful additive manufacturing method. In certain embodiments, the consolidation of powder particles may be carried out in a layer-by-layer deposited powder bed using a three-dimensional printing system that uses a laser or electron beam to heat precise locations in the powder bed, thereby solidifying specific powder particles and forming a part having a predetermined shape. Selective laser sintering (SLS) represents a particular example of a process suitable for promoting localized consolidation of powder particles during powder bed fusion to form parts of desired shapes. Other localized heating techniques for particle consolidation that can also be used include, for example, electron beam melting (EBM), binder jetting, multi-jet fusion (MJF), and selective heat melting (SHM).

[0004] Among powder particulates, those suitable for use in three-dimensional printing include thermoplastic polymers. While a wide range of thermoplastic polymers are known, relatively few have properties compatible for use in current three-dimensional printing technologies that employ particulate consolidation. Thermoplastic polymers suitable for undergoing particulate consolidation into parts may include those that have a significant difference between the onset of melting and the onset of crystallization, which may promote good structural and mechanical integrity after targeted heating to promote particulate consolidation. The ability to readily form particulates suitable for deposition in a powder bed is also an important consideration.

[0005] To achieve satisfactory printing performance, thermoplastic particulates must maintain good flow properties in the solid state. Flow properties can be evaluated, for example, by measuring the portion of thermoplastic particulates from a sample that can pass through a standard sieve of a particular size and / or by measuring the angle of repose. A high percentage of sievable thermoplastic particulates may indicate that the thermoplastic particulates are not agglomerated and exist essentially as individual particles, which may be characteristic of easy powder flow. In contrast, a low angle of repose value may be characteristic of powder flowability. A relatively narrow particle size distribution and regularity of particle shape in a sample may also promote good powder flow performance. To promote powder flow, a substantial absence of fine particulate dust may be desirable.

[0006] Thermoplastic particulates are often commercially obtained by cryogenic grinding or precipitation processes, which can result in irregular particle shapes and wide particle size distributions. Irregular particle shapes and wide particle size distributions can also lead to poor powder flowability and extensive void formation during the three-dimensional printing process. Poor powder flowability can be addressed to some extent by dry blending with fillers and flow aids, but these layering methods can be limited in effectiveness when using softer polymer materials such as elastomers due to particle agglomeration. In addition, fillers and flow aids may not be desirable to incorporate into printed objects in some cases.

[0007] Void formation resulting from irregular particle shapes can be more difficult to address. Extensive void formation during particulate consolidation can significantly reduce the final material strength of the print compared to that otherwise obtained by casting or machining the same thermoplastic polymer. Therefore, it may be desirable to achieve good flow performance when the thermoplastic particulate is liquefied to promote adequate particulate consolidation with limited void formation.

[0008] Thermoplastic microparticles may be formed by a melt-emulsification process, such as that described in U.S. Patent No. 4,863,646, the entirety of which is incorporated herein by reference. In the melt-emulsification process, a thermoplastic polymer is dispersed as liquefied droplets in a dispersion medium in which the thermoplastic polymer has no or minimal solubility above the melting point or softening temperature of the polymer. When the liquefied droplets are cooled below the melting point or softening temperature, substantially spherical thermoplastic microparticles can be formed, although with a wide particle size distribution. Therefore, thermoplastic microparticles produced by conventional melt-emulsification processes may not be ideally suited for three-dimensional printing processes. Summary of the Invention [Problem to be solved by the invention]

[0009] The particle size distribution of thermoplastic microparticles formed during melt-emulsification can be significantly narrowed by incorporating multiple nanoparticles into the dispersion medium, as described in U.S. Patent Application No. 16 / 946,622, filed June 30, 2020, and incorporated herein by reference. Various types of silica and other inorganic nanoparticles may be particularly desirable in this regard. The thermoplastic microparticles thus formed can be characterized by at least a partial coating of nanoparticles on the microparticle surface, with the nanoparticles firmly adhered to and / or embedded in the microparticle surface. The adhered / embedded nanoparticles can promote powder flow performance that is significantly better than that achieved when dry-blending uncoated thermoplastic microparticles with a flow aid. The narrow particle size distribution of thermoplastic microparticles with a nanoparticle coating thereon can often enable rapid sintering with a manageable amount of void formation. While a wide range of prints can be successfully formed with silica-coated thermoplastic microparticles, there are certain instances in which incorporating silica or other inorganic nanoparticles into printed objects may not be desirable. For example, excess silica or inorganic nanoparticles can, in some cases, impair the mechanical performance of the printed object. Although polymeric nanoparticles can be a sufficient replacement for silica and other inorganic nanoparticles, there are a few types of polymeric nanoparticles that are easily formable, compatible with melt-emulsification conditions, promote good flow performance, and limit void formation during additive manufacturing.

[0010] The present disclosure provides a particulate composition suitable for additive manufacturing, the particulate composition comprising a plurality of thermoplastic particulates comprising a thermoplastic polymer and a plurality of polymeric nanoparticles disposed on an outer surface of the thermoplastic particulates, the polymeric nanoparticles comprising a crosslinked fluorinated polymer. The present disclosure also provides a method for forming a consolidated part using a particulate composition. The method includes providing a particulate composition including a plurality of thermoplastic particulates comprising a thermoplastic polymer and a plurality of polymeric nanoparticles disposed on the outer surfaces of the thermoplastic particulates, the polymeric nanoparticles comprising a crosslinked fluorinated polymer; depositing the particulate composition layer by layer onto a powder bed; and heating a portion of the powder bed to consolidate the portion of the thermoplastic particulates into a consolidated part having a specific shape. The consolidated part may include a thermoplastic matrix formed by consolidation of the thermoplastic particulates and the polymeric nanoparticles mixed with the thermoplastic matrix.

[0011] The present disclosure also provides a method for forming a particulate composition suitable for additive manufacturing, comprising: combining a thermoplastic polymer and polymeric nanoparticles with a dispersion medium at a heating temperature equal to or greater than the melting or softening temperature of the thermoplastic polymer and less than the melting, softening, or decomposition temperature of the polymeric nanoparticles, wherein the thermoplastic polymer and the polymeric nanoparticles are substantially immiscible in the dispersion medium at the heating temperature, and the polymeric nanoparticles comprise a crosslinked fluorinated polymer; applying a shear force sufficient to disperse the thermoplastic polymer as liquefied droplets in the dispersion medium at the heating temperature in the presence of the polymeric nanoparticles; after the liquefied droplets are formed, cooling the dispersion medium to a temperature at which at least solidified thermoplastic particulates are formed, wherein the thermoplastic particulates comprise the thermoplastic polymer and at least a portion of the polymeric nanoparticles disposed on an outer surface of the thermoplastic particulates; and separating the thermoplastic particulates from the dispersion medium. [Brief explanation of the drawings]

[0012] 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.

[0013] [Figure 1] FIG. 1 is a flow chart of a non-limiting exemplary method for producing thermoplastic particulates according to the present disclosure.

[0014] [Figure 2] FIG. 2 is a scanning electron microscope image of polyurethane microparticles prepared according to Example 1.

[0015] [Figure 3] FIG. 3 is a graph showing the particle size distribution of polyurethane microparticles prepared according to Example 1.

[0016] [Figure 4] FIG. 4 is a scanning electron microscope image of polyamide microparticles prepared according to Example 4.

[0017] [Figure 5] FIG. 5 is a graph showing the particle size distribution of polyamide microparticles prepared according to Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present disclosure relates generally to additive manufacturing, and more particularly to additive manufacturing processes characterized by the consolidation of powder particulates with improved sintering characteristics.

[0019] As discussed above, thermoplastic particulates, including thermoplastic polymers, may be suitable for use in three-dimensional printing processes, particularly those that use selective laser sintering and similar processes to consolidate designated locations in a powder bed to form parts having a predetermined shape. Currently commercially available thermoplastic particulates may be obtained with irregular shapes and / or wide particle size distributions, which can lead to poor flow performance and / or incomplete particulate consolidation during printing. A melt-emulsification process using silica and other inorganic nanoparticles during thermoplastic particulate formation can result in thermoplastic particulates with high sphericity and narrow particle size distributions, thereby improving powder flow performance and particulate consolidation characteristics. While silica and other inorganic nanoparticles can generally be suitably incorporated into printed objects, there are certain instances in which the incorporation of such nanoparticles may lead to undesirable or ineffective particulate consolidation. A small concentration window may exist that is effective in incorporating silica or other inorganic nanoparticles into thermoplastic particulates in an amount suitable to form a desired particle size range while still allowing for effective particulate consolidation. Thus, in some cases, it can be very difficult to achieve a balance between adequate powder flow performance and good liquid flow performance when consolidating thermoplastic powder particulates stabilized with silica or other inorganic nanoparticles.

[0020] Polymer nanoparticles may represent a suitable alternative to silica and other inorganic nanoparticles because they may be more readily compatible with the polymer matrix of the printed object after particulate consolidation. However, there are relatively few types of polymer nanoparticles that can be suitably formed and subsequently isolated (e.g., as a latex emulsion followed by isolation of the emulsion particles), are compatible with melt-emulsification conditions (e.g., polymers that are insoluble in the melt-emulsification medium and do not melt or decompose at the melt-emulsification temperatures used), and can effectively promote powder flow to limit void formation during particulate consolidation. According to the present disclosure, crosslinked fluorinated polymers, particularly crosslinked fluorinated acrylic polymers, can surprisingly meet all of these desirable attributes, as discussed in more detail below. A wide range of compositional variations can be accommodated in crosslinked fluorinated acrylic polymers, including the incorporation of non-fluorinated ethylenically unsaturated monomers and / or varying crosslink density to facilitate tuning of the physical properties of the polymer nanoparticles.

[0021] Both crosslinking and fluorination are believed to be desirable to promote compatibility with melt-emulsification conditions according to the present disclosure. For example, non-fluorinated crosslinked acrylic polymers may decompose at temperatures below those typically used during melt-emulsification, thereby hindering their ability to promote stabilization of thermoplastic microparticles. Non-crosslinked polymers may similarly decompose and / or melt at temperatures typically used during melt-emulsification. While various fluorinated polymers (e.g., polytetrafluoroethylene) with high thermal stability are known, effective emulsification techniques for producing these types of polymers in nanoparticle form are not believed to be currently known.

[0022] In some examples, a combination of crosslinked fluorinated polymer nanoparticles and silica nanoparticles or other inorganic nanoparticles may be used in the present disclosure. For example, crosslinked fluorinated polymer nanoparticles may be used in an effective amount to reduce the amount of silica or inorganic nanoparticles to a level that remains effective during melt emulsification but is not problematic during particulate consolidation. Such an approach may be more cost-effective than the complete replacement of silica or inorganic nanoparticles with crosslinked fluorinated polymer nanoparticles, as discussed herein. However, it should be understood that the complete replacement of silica or other inorganic nanoparticles with polymer nanoparticles may be more desirable in some cases.

[0023] The terms used in the description and claims of this specification have their plain and ordinary meanings except as modified by the following paragraphs.

[0024] As used herein, the term "thermoplastic polymer" refers to a polymeric material that reversibly softens and hardens upon heating and cooling above a particular temperature (e.g., melting point, softening point, glass transition temperature, etc.) Thermoplastic polymers include both elastomeric and non-elastomeric thermoplastic polymers.

[0025] As used herein, the term "polymer" refers to an oligomeric material formed from one or more organic monomers.

[0026] As used herein, the term "nanoparticle" refers to particulate matter having a particle size ranging from about 1 nm to about 500 nm.

[0027] As used herein, the term "oxide" refers to both metal and non-metal oxides. For purposes of this disclosure, silicon is considered to be a metal.

[0028] As used herein, the term "oxide nanoparticles" refers to particulate materials having a particle size ranging from about 1 nm to about 500 nm and comprising metal oxides or non-metal oxides.

[0029] As used herein, the term "inorganic nanoparticles" refers to any nanoparticles that are not polymeric nanoparticles.

[0030] As used herein, the term "associated" refers to a chemical bond, physical incorporation with a matrix, or physical adhesion to a surface.

[0031] As used herein, the terms "mixed," "admixed," and related terms refer to the dissolution of a first substance in a second substance or the dispersion of a first substance as a solid in a second substance, which dispersion may be uniform or non-uniform.

[0032] As used herein, the term "D 10 " refers to a diameter where 10% of the sample (by volume unless otherwise specified) consists of particles having a diameter less than that diameter value. As used herein, the term "D 50 " refers to a diameter where 50% of the sample (by volume unless otherwise specified) consists of particles with a diameter less than the diameter value in question. 50 may also be referred to as "average particle size." As used herein, the term "D 90 " refers to the diameter where 90% of the sample (by volume unless otherwise specified) consists of particles having a diameter less than that diameter value.

[0033] As used herein, the terms "diameter span," "span," and "span size" provide an indication of the width of the particle size distribution (D 90 -D 10 ) / D 50 (Again, unless otherwise specified, each D value is based on volume).

[0034] As used herein, the term "shear force" refers to stirring or similar processes that induce mechanical agitation in a fluid.

[0035] As used herein, the term "embedded" with respect to the surface of nanoparticles and thermoplastic microparticles refers to nanoparticles that simply rest on the surface of the polymer particle, thereby extending at least partially into the surface such that the polymer contacts the nanoparticles more tightly than if they were in tangential contact with the surface.

[0036] As used herein, the terms "circularity" and "sphericity" refer to the proximity of a microparticle or microparticles to a perfect sphere. To determine circularity, an optical microscope image of the microparticle is taken. The perimeter (P) and area (A) of the particle in the plane of the microscope image are calculated (e.g., using a SYSMEX FPIA 3000 Particle Shape and Size Analyzer available from Malvern Instruments). The circularity of a microparticle is expressed as C EA / P, wherein C EA is the circumference of a circle with an area equivalent to the area of ​​the actual particle (A).

[0037] As used herein, viscosity of the carrier fluid refers to the kinematic viscosity at 25° C. unless otherwise specified, and is measured according to ASTM D445-19 unless otherwise specified.

[0038] Melting points of thermoplastic polymers herein are determined by ASTM E794-06(2018) at a heating and cooling rate of 10°C / min unless otherwise specified.

[0039] The softening temperature or softening point of the thermoplastic polymers herein is determined by ASTM D6090-17 unless otherwise specified. Softening temperature may be measured using a cup and ball apparatus available from Mettler-Toledo using a 0.50 g sample at a heating rate of 1° C. / min.

[0040] As used herein, the term "fluorinated" refers to a polymer or monomer unit thereof that contains at least one fluorine atom covalently bonded thereto.

[0041] As used herein, the term "perfluorinated" refers to a polymer or its monomer units that has all available hydrogen atoms of a particular type replaced with fluorine atoms.

[0042] As used herein, the term "crosslinked" refers to a polymeric material having covalently bonded groups between two different monomeric units. The crosslinks may be within a given polymer chain (intramolecular), between two or more different polymer chains (intermolecular), or any combination thereof.

[0043] As used herein, the term "(meth)acrylic monomer" refers to a family of monomers that include acrylic acid, methacrylic acid, or derivative forms thereof. Suitable derivative forms of (meth)acrylic monomers may include esters or amides. Thus, for any particular (meth)acrylic monomer disclosed herein, both acrylic and methacrylic forms are expressly disclosed.

[0044] As used herein, the terms "latex," "latex emulsion," and "latex dispersion" refer to equivalent aqueous emulsions containing emulsified polymeric microparticles.

[0045] Thus, the particulate composition of the present disclosure may comprise a plurality of thermoplastic particulates comprising a thermoplastic polymer and a plurality of nanoparticles disposed on the outer surface of the thermoplastic particulates. The polymeric nanoparticles comprise crosslinked fluorinated polymers, suitable examples of which are discussed in more detail below.

[0046] Suitable crosslinked fluorinated polymers may comprise at least one fluorinated monomer and at least one crosslinking agent, at least one non-fluorinated monomer and at least one fluorinated crosslinking agent, at least one fluorinated monomer and at least one fluorinated crosslinking agent, or any combination thereof. Particularly suitable crosslinked fluorinated polymers may be formed through the polymerization of at least one ethylenically unsaturated monomer, particularly a (meth)acrylic monomer, and at least one crosslinking agent having two or more ethylenic unsaturations. At least one of the at least one ethylenically unsaturated monomer and the at least one crosslinking agent may be fluorinated. More specific examples of suitable crosslinked fluorinated polymers may include those that can be formed by emulsion polymerization, which may allow the fluorinated crosslinked polymer to be easily isolated as polymer nanoparticles after solvent removal from the emulsion (e.g., by spray drying). Suitable emulsion polymerization reaction conditions are described in more detail below.

[0047] More specific examples of crosslinked fluorinated polymers suitable for forming polymeric nanoparticles may include fluorinated (meth)acrylic monomers, particularly fluorinated (meth)acrylic ester monomers, and divinyl crosslinkers. 2,2,2-Trifluoromethyl (meth)acrylate and divinylbenzene represent an exemplary pairing of a fluorinated (meth)acrylic monomer and a divinyl crosslinker.Some or other examples of crosslinked fluorinated polymers include, but are not limited to, pentafluorophenyl (meth)acrylate, 2,4,6 trifluorophenyl (meth)acrylate, 2,2,3,3,3-pentafluoropropyl (meth)acrylate, perfluoropropyl (meth)acrylate, 1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylate, perfluoroisopropyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3,4,4,4-heptafluorobutyl (Meth)acrylate, 2,2,3,3,4,4-hexafluorobutyl (meth)acrylate, 2,2,3,4,4,4-hexafluorobutyl (meth)acrylate, perfluorobutyl (meth)acrylate, 2,2,3,3,4,4,5,5-octafluoropentyl (meth)acrylate, 2,2,3,3,4,4,5,5,5-nonafluoropentyl (meth)acrylate, perfluoropentyl (meth)acrylate, 3,3,4,4,5,5,6,6,6-nonafluorohexyl (meth)acrylate, 2,2,3,3,4,4,5 ,5,6,6,7,7-dodecafluoroheptyl (meth)acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl (meth)acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptafluorodecyl (meth)acrylate, octafluoropentyl (meth)acrylate, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12-heneicosafluorodecyl (meth)acrylate, 2-[1',1',1'-fluoro Fluorinated (meth)acrylic monomers may include 1H,1H,2H,2H-heptadecafluorodecyl methacrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 2-[(1',1',1'-trifluoro-2'-(trifluoromethyl)-2'-hydroxy)propyl]-3-norbornyl (meth)acrylate, any combination thereof, and the like.The corresponding amide forms of the aforementioned (meth)acrylic monomers may optionally be used.

[0048] Any of the foregoing fluorinated (meth)acrylic monomers may be crosslinked with a divinyl crosslinker, such as divinylbenzene or other suitable crosslinker containing at least two vinyl groups. Suitable crosslinkers for facilitating the crosslinking of ethylenically unsaturated monomers, particularly fluorinated (meth)acrylic monomers, include, but are not limited to, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. , 2,2'-bis(4-((meth)acryloxy / diethoxy)phenyl)propane, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2'-bis(4-((meth)acryloxy / polyethoxy)phenyl)propane, divinylbenzene, divinylnaphthalene, divinyl ether, any combination thereof, and the like. Dienes such as 1,3-butadiene and isoprene may optionally include a suitable crosslinking agent.

[0049] Additionally, crosslinkers can be fluorinated to produce suitable crosslinked fluorinated polymers. Fluorinated crosslinkers can be utilized to crosslink fluorinated polymers (e.g., polymers containing fluorinated monomers such as fluorinated (meth)acrylic monomers) or otherwise non-fluorinated polymers. Suitable fluorinated crosslinkers can include, for example, fluorinated divinyl crosslinkers such as 1,8-divinylperfluorooctane, 1,6-divinylperfluorohexane, and 1,4-divinylperfluorobutane.

[0050] The molar ratio of a crosslinker containing at least two vinyl groups, such as divinylbenzene, can be selected to provide a desired crosslink density in the crosslinked fluorinated polymers disclosed herein. The crosslink density can be selected, for example, to alter the melting point or decomposition temperature of the polymeric nanoparticles. In a non-limiting example, the crosslinker, such as a divinyl crosslinker, can be present in an amount ranging from about 1 mol% to about 50 mol%, relative to the total monomers undergoing polymerization to form the polymeric nanoparticles disclosed herein. In more specific examples, the amount of crosslinker can range from about 1 mol% to about 10 mol%, or from about 10 mol% to about 25 mol%, or from about 25 mol% to about 40 mol%, or from about 40 mol% to about 50 mol%.

[0051] Commercially available divinylbenzene may contain up to about 30% by weight of divinylbenzene and up to about 50% by weight of ethylvinylbenzene. Although ethylvinylbenzene does not contain two vinyl groups to facilitate crosslinking, it may be copolymerized with ethylenically unsaturated monomers, such as the fluorinated (meth)acrylic monomers described above. Thus, certain fluorinated crosslinked polymers of the present disclosure may include fluorinated (meth)acrylic monomers copolymerized with ethylvinylbenzene monomers, where at least a portion of the fluorinated (meth)acrylic monomers and / or ethylvinylbenzene monomers are further crosslinked with divinylbenzene.

[0052] Thus, the crosslinked fluorinated polymer of the present disclosure, such as a crosslinked fluorinated polymer comprising a fluorinated (meth)acrylic monomer and a divinylbenzene crosslinker, may further comprise an ethylenically unsaturated comonomer different from the fluorinated (meth)acrylic monomer. The ethylenically unsaturated comonomer may be fluorinated or non-fluorinated. The ethylenically unsaturated comonomer may, in some embodiments, be ethylvinylbenzene.

[0053] Other suitable examples of ethylenically unsaturated monomers that can be copolymerized with the fluorinated (meth)acrylic monomer and the divinyl crosslinker are not considered to be particularly limited, provided that polymeric nanoparticles can be formed therefrom by emulsion polymerization. Suitable ethylenically unsaturated comonomers can include, for example, (meth)acrylamide monomers, amine-functionalized (meth)acrylate monomers, polyether-functionalized (meth)acrylate monomers, etc. Specific examples of suitable comonomers may include, for example, n-butyl (meth)acrylate, isobutyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cycloalkyl (meth)acrylates such as isobornyl (meth)acrylate and cyclohexyl (meth)acrylate, (meth)acrylamide, hydroxy-functionalized (meth)acrylate monomers such as hydroxyethyl (meth)acrylate and hydroxylpropyl (meth)acrylate, and (meth)acrylamide derivatives such as N-methylol (meth)acrylamide and diacetone (meth)acrylamide.

[0054] Other suitable ethylenically unsaturated monomers that may be present in the crosslinked fluorinated polymers disclosed herein may contain at least one amine group, which may be a primary amine, secondary amine, or tertiary amine. Particularly suitable examples of ethylenically unsaturated monomers containing at least one amine group include, for example, 2-(dimethylamino)ethyl (meth)acrylate, 3-(dimethylamino)propyl (meth)acrylate, 2-(diethylamino)ethyl (meth)acrylate, 3-(diethylamino)propyl (meth)acrylate, 2-(ethylamino)ethyl (meth)acrylate, 3-(ethylamino)propyl (meth)acrylate, 2-(methylamino)ethyl (meth)acrylate, 3-(methylamino)propyl (meth)acrylate, 2-(tert-butylamino)ethyl (meth)acrylate, 3-(tert-butylamino)propyl (meth)acrylate. Examples of (meth)acrylate monomers include acrylate, 2-(dimethylamino)ethyl(meth)acrylamide, 3-(dimethylamino)propyl(meth)acrylamide, 2-(diethylamino)ethyl(meth)acrylamide, 3-(dimethylamino)propyl(meth)acrylamide, 2-(methylamino)ethyl(meth)acrylamide, 3-(methylamino)propyl(meth)acrylamide, 2-(ethylamino)ethyl(meth)acrylamide, 3-(ethylamino)propyl(meth)acrylamide, 2-(tert-butylamino)ethyl(meth)acrylamide, and 3-(tert-butylamino)propyl(meth)acrylamide. Vinylamine may also represent a suitable comonomer in some cases.

[0055] Alpha olefins are another type of ethylenically unsaturated monomer that can be present as a comonomer in the polymer nanoparticles disclosed herein.Suitable alpha olefins that can be present in the polymer nanoparticles of the present disclosure include, but are not limited to, ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, or any combination thereof.Linear alpha olefins with an even number of carbon atoms can be particularly suitable due to their commercial availability.

[0056] Still other examples of ethylenically unsaturated monomers that may be present in the polymeric nanoparticles of the present disclosure include, for example, styrene or substituted variants thereof, vinyl esters, e.g., vinyl acetate, vinyl alkanoates, or derivatives thereof, nitriles such as (meth)acrylonitrile and fumaronitrile, ethylenically unsaturated halides such as vinyl chloride and vinylidene chloride, any of which may be present in combination with one or more of the ethylenically unsaturated monomers listed above.

[0057] Still other examples of ethylenically unsaturated monomers that may be present as comonomers in the polymeric nanoparticles of the present disclosure include, but are not limited to, methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, acrolein, methacrolein, crotonaldehyde, acetoacetoxyethyl (meth)acrylate (AAEM), glycidyl (meth)acrylate, and any combination thereof.

[0058] Ethylenically unsaturated monomers having at least one acidic group can also be present as comonomers in the polymeric nanoparticles of the present disclosure. Such ethylenically unsaturated monomers can have pendant carboxylic or sulfonic acids. Illustrative examples include, but are not limited to, maleic acid, methyl hydrogen maleate, ethyl hydrogen maleate, itaconic acid, fumaric acid, crotonic acid, citraconic acid, styrenesulfonic acid, and vinyl-derivatized 2-aminomethylpropanesulfonic acid. The carboxylic acid forms of the aforementioned monomers may also be present in esterified forms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, and the like. Other suitable esterified monomers may contain ethylenically unsaturated groups in the alcohol-derived portion of the esterified monomer. Such ethylenically unsaturated monomers can include, for example, vinyl acetate, allyl acetate, vinyl propionate, allyl propionate, vinyl benzoate, allyl benzoate, and the like.

[0059] Polymerization to obtain a crosslinked fluorinated polymer utilizing any of the aforementioned fluorinated (meth)acrylic monomers, ethylenically unsaturated comonomers, and crosslinkers can be carried out via emulsion polymerization, in a non-limiting embodiment. Once polymerization is carried out under suitable emulsion polymerization conditions to obtain a crosslinked fluorinated polymer, the polymeric nanoparticles can be obtained in at least partially isolated form by removing the solvent from the emulsion (e.g., by spray drying or evaporation) and / or by removing the polymeric nanoparticles from the emulsion (e.g., by filtration or centrifugation). Suitable emulsion polymerization conditions are well known to those skilled in the art and are briefly summarized below.

[0060] Suitable emulsion polymerization conditions can be characterized by the aqueous fluid in which the emulsion polymerization is conducted. Aqueous fluids suitable for use in the present disclosure can include water or water mixed with a water-miscible organic solvent, such as an alcohol or glycol. The aqueous fluid and resulting polymer emulsion can be acidic, neutral, or basic, depending on the needs of a particular application. A specific pH can be selected to maintain or break the emulsion, for example, optionally with buffering, if necessary. Suitable pH values ​​during emulsion polymerization can range from about 1 to about 7, or from about 2 to about 6, or from about 1 to about 6, or from about 6 to about 7, or from about 6 to about 8, or from about 7 to about 8, or from about 7 to about 14, or from about 8 to about 14, or from about 8 to about 12, or from about 7 to about 9.

[0061] According to some embodiments, the aqueous fluid may include at least one surfactant to promote emulsification. Suitable surfactants may be cationic, anionic, zwitterionic, nonionic, or any combination thereof. Exemplary nonionic surfactants may include, for example, alkylaryl polyether alcohols, alkylphenol ethoxylates, alkyl ethoxylates, poloxamers, fatty acid esters (e.g., fatty acid glycerol esters, fatty acid sorbitan esters, fatty acid sorbitol esters, fatty acid lecithin esters, etc.), polyethylene oxide sorbitan fatty acid esters, and any combination thereof. Polymer colloids such as polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, and other cellulose derivatives may also include suitable nonionic surfactants. Exemplary anionic surfactants that may be suitable for use in the present disclosure include, but are not limited to, alkyl ethoxylate sulfates, alkyl ethoxylate sulfonates, alkylphenol ethoxylate sulfates, alkylphenol ethoxylate sulfonates, alkyl sulfates, alkyl sulfonates, alkylaryl sulfates, alkylaryl sulfonates, sulfosuccinates, and any combination thereof. Exemplary zwitterionic surfactants that may be suitable for use in the present disclosure include various betaines and sultaines. The at least one surfactant may be present in the polymer emulsion of the present disclosure in an amount ranging from about 0.2% to about 10% by weight, or from about 0.2% to about 7% by weight, measured based on total solids.

[0062] Emulsion polymerization of ethylenically unsaturated monomers can be carried out in the presence of at least one radical initiator. The at least one radical initiator can be present in an amount of from about 0.1 to about 8 weight percent of the monomers being polymerized. Suitable radical initiators may be capable of promoting radical polymerization under thermal or photolytic conditions in the emulsion. Such radical initiators can include, but are not limited to, redox systems including reducing agents such as sodium persulfate or other alkali metal persulfates, ammonium persulfate, azo compounds (e.g., 4,4-azobis-cyanovaleric acid and / or AIBN), sodium hydroxymethanesulfonate (sodium formaldehyde sulfoxylate) and ascorbic acid, oxidizing initiators such as t-butyl hydroperoxide, and any combination thereof.Other suitable radical initiators include, for example, 2,2'-azobis(2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2'-azobis[N-(4-chlorophenyl)-2-methylpropionamidine] dihydrochloride, 2,2'-azobis[N-(4-hydroxyphenyl)-2-methyl-propionamidine] dihydrochloride, 2,2'-azobis[N-(4-amino-phenyl)-2-methylpropionamidine] tetrahydrochloride, 2,2'-azobis[2-methyl-N(phenylmethyl)propionamidine] dihydrochloride, 2,2'-azobis[2-methyl-N-2-propenylpropionamidine] dihydrochloride, 2,2'-azobis[N-(2-hydroxy-ethyl)-2-methylpropionamidine] dihydrochloride, chloride, 2,2'-azobis[2(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(3,4,5,6-tetrahydro-1H-1,3-diazepin-2-yl)propane]dihydrochloride Examples of suitable azoamidine compounds include 2,2'-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl)propane]dihydrochloride, 2,2'-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochloride, and combinations thereof. Thermal radical polymerization conditions can occur at temperatures ranging from about 20°C to about 90°C.

[0063] Once formed by emulsion polymerization, the polymeric nanoparticles may be recovered by any suitable technique, such as filtration, centrifugation, spray drying, or any combination thereof.

[0064] Additional nanoparticles may be present in combination with polymer nanoparticles on the outer surface of the thermoplastic particulate, particularly inorganic nanoparticles selected from oxide nanoparticles, carbon black, or any combination thereof. Oxide nanoparticles suitable for use in the present disclosure may include, for example, silica nanoparticles, titania nanoparticles, zirconia nanoparticles, alumina nanoparticles, iron oxide nanoparticles, copper oxide nanoparticles, tin oxide nanoparticles, boron oxide nanoparticles, cerium oxide nanoparticles, thallium oxide nanoparticles, tungsten oxide nanoparticles, or any combination thereof. Mixed oxides formed as nanoparticles, such as aluminosilicates, borosilicates, and aluminoborosilicates, are also encompassed by the term "oxide" and may be suitable for use in the present disclosure. Oxide nanoparticles may be hydrophilic or hydrophobic in nature, may be native to the nanoparticles, or may be the result of a surface treatment of the nanoparticles. For example, silica nanoparticles with hydrophobic surface treatments, such as dimethylsilyl or trimethylsilyl, may be formed by reacting hydrophilic surface hydroxyl groups with an appropriate functionalizing agent. While hydrophobically functionalized oxide nanoparticles may be particularly desirable in the methods and compositions of the present disclosure, non-functionalized oxide nanoparticles or hydrophilically modified oxide nanoparticles may also be suitable for use. For example, hydrophobically functionalized oxide nanoparticles may be particularly compatible with hydrophobic fluids used as the carrier fluid in melt-emulsification processes, as discussed further below.

[0065] Silica nanoparticles, particularly fumed silica nanoparticles with hydrophobic functionalization, may be particularly suitable for use in combination with polymeric nanoparticles in the present disclosure, since a wide variety of functionalized silicas are available with different types of hydrophobic functionalization and a wide range of particle sizes. Silazane and silane hydrophobic functionalization are included among the hydrophobic functionalizations that may be present in silica nanoparticles that are compatible for use in the present disclosure. The combination of polymeric and silica nanoparticles may impart specific properties to thermoplastic particulates or consolidated objects formed therefrom that may not be realized when using silica nanoparticles or polymeric nanoparticles alone.

[0066] The introduction of hydrophobic functional groups may reduce the water compatibility of silica nanoparticles compared to unfunctionalized silica nanoparticles. Suitable hydrophobic functionalization may be non-covalently or covalently bound to the surface of the silica nanoparticles. Covalent binding can be achieved, for example, by functionalizing surface hydroxyl groups on the surface of the silica nanoparticles. In a non-limiting example, silica nanoparticles can be treated with hexamethyldisilazane to obtain covalent binding of hydrophobic functionalization. Commercially available hydrophobically functionalized silica nanoparticles that can be used in combination with polymer nanoparticles include, but are not limited to, Aerosil RX50 (Evonik, average particle size = 40 nm) and Aerosil R812S (Evonik, average particle size = 7 nm).

[0067] Carbon black is another type of nanoparticle that may be present on the thermoplastic particulates combined with polymeric nanoparticles in the present disclosure. Various grades of carbon black are well known to those skilled in the art, and any of these may be suitable for use in the present disclosure. Various types of oxide nanoparticles may also be present in some examples in combination with polymeric nanoparticles in the present disclosure.

[0068] The loading and particle size of various types of nanoparticles on the thermoplastic microparticles of the present disclosure can vary over a wide range. The nanoparticle loading of polymeric nanoparticles or similar types of nanoparticles can depend on the nanoparticle concentration in the dispersing medium used to promote the formation of the thermoplastic microparticles under melt-emulsification conditions, as described further below. In non-limiting examples, the concentration of nanoparticles in the dispersing medium can range from about 0.01% to about 10% by weight, or from about 0.05% to about 10% by weight, or from about 0.05% to about 5% by weight, or from about 0.1% to about 2% by weight, or from about 0.25% to about 1.5% by weight, or from about 0.2% to about 1.0% by weight, or from about 0.25% to about 1% by weight, or from about 0.25% to about 0.5% by weight, based on the weight of the thermoplastic polymer. The aforementioned weight percentages refer to the weight percentage of polymeric nanoparticles, or the combined weight percentage of polymeric nanoparticles and at least one other type of nanoparticle, such as silica nanoparticles, which may be present. When polymeric nanoparticles are used in combination with another type of nanoparticle, the polymeric nanoparticles and at least one other type of nanoparticle (e.g., silica nanoparticles) may be present in combination with one another in any ratio ranging from about 1:99 to about 99:1 by weight.

[0069] The particle size of the nanoparticles, especially polymeric nanoparticles, can range from about 1 nm to about 100 nm, although particle sizes up to about 500 nm may be acceptable. 50 The particle size of the nanoparticles, particularly polymeric nanoparticles, may range from about 5 nm to about 500 nm, or from about 5 nm to about 100 nm, or from about 5 nm to about 75 nm, or from about 5 nm to about 50 nm, or from about 5 nm to about 10 nm, or from about 10 nm to about 20 nm, or from about 20 nm to about 30 nm, or from about 30 nm to about 40 nm, or from about 40 nm to about 50 nm, or from about 50 nm to about 60 nm. When polymeric nanoparticles are present in combination with another type of nanoparticle, such as silica nanoparticles, the size of the polymeric nanoparticles may be substantially the same as or different from the size of the other type of nanoparticle, such as silica nanoparticles. When used in combination, the polymeric nanoparticles may be larger or smaller than the other type of nanoparticles.

[0070] Silica nanoparticles and similar oxide nanoparticles suitable for use in the present disclosure have a particle size of about 10 m 2 / g~about 500m 2 / g, or approximately 10 m 2 / g~about 150m 2 / g, or approximately 25m 2 / g~about 100m 2 / g, or approximately 100m 2 / g ~ approx. 250m 2 / g, or approximately 250m 2 / g~about 500m 2 / g BET surface area.

[0071] Specific examples of oxide nanoparticles suitable for use in the present disclosure in combination with polymer nanoparticles may include, for example, hexamethyldisilazane (HMDS), dimethyldichlorosilane, or other long-chain alkylsilanes such as decyltriethoxysilane or octyltriethoxysilane. Suitable oxide nanoparticles may vary in size from about 7 nm to about 130 nm. Specific commercial examples of hydrophobically treated silicas, their particle sizes, and their hydrophobic treatments include the following: Wacker HDK® H13TD (16 nm, PDMS), HDK® H13™ (16 nm, HMDS), HDK® H13TX (16 nm, HMDS / PDMS), HDK® H20TD (12 nm, PDMS), HDK® H20™ (12 nm, HMDS), HDK® H20TX (12 nm, HMDS / PDMS), HDK® H30TD (8 nm, PDMS), HDK® H30™ (8 nm, HMDS), HDK® H30TX (8 nm, HMDS / PDMS), HDK® H3004 (12 nm, HMDS), HDK® HO5TD (40 nm, PDMS), HDK® HO5™ (40 nm, HMDS), HDK® HO5TX (40 nm, HMDS / PDMS), Evonik R972 (16 nm, DDS), RY200S (16 nm, PDMS, BET surface area = 200 m 2 / g), R202 (16 nm, PDMS), R974 (12 nm, DDS), RY200 (12 nm, PDMS), RX200 (12 nm, HMDS), R8200 (12 nm, HMDS), R805 (12 nm, alkylsilane), R104 (12 nm, alkylsilane), RX300 (7 nm, HMDS), R812 (7 nm, HMDS), R812S (7 nm, HMDS, BET surface area = 300 m 2 / g), R106 (7 nm, alkylsilane), NY50 (30 nm, PDMS), NAX50 (30 nm, HMDS), RY50 (40 nm, PDMS), and RX50 (40 nm, HMDS), Cabot TS530 (8 nm, HMDS), and Shin-Etsu sol-gel silica X24-9163A (110 nm, HMDS, BET surface area = 25 m 2 / g) and X24-9600 A-80 (80 nm, HMDS, BET = 40 m 2 / g) may be mentioned.

[0072] Suitable oxide nanoparticles may include a treatment involving a base or a base salt. Specific commercial examples of such treated oxide nanoparticles, their particle sizes, and their treatments include the following types of silica nanoparticles: Wacker Treated Silica HDK® H13TA (16 nm, PDMS-NR2 / NR3) + ), HDK® H30TA (8 nm, PDMS-NR2 / NR3 + ), HDK® H2015EP (12 nm, PDMS-NR2 / NR3 + ), HDK (registered trademark) H2050EP (10 nm, PDMS-NR2 / NR3 + ), HDK® H2150VP (10 nm, PDMS-NR2 / NR3 + ), and HDK® H3050VP (8 nm, PDMS-NR2 / NR3 + ) are listed.

[0073] Other suitable oxide nanoparticles, including both treated and untreated variants, can include titanates, such as CaTiO, BaTiO, MgTiO, MnTiO, SrTiO, and AlTiO.

[0074] Also suitable for use in the present disclosure in combination with polymeric nanoparticles are treated or untreated aluminum oxides. Specific commercially available examples of aluminum oxides, their particle sizes, and their treatments include, for example, Evonik C805 (13 nm, octylsilane), Aluminum Oxide C (13 nm, untreated), Aeroxide Alu C 100 (10 nm, untreated), Aeroxide Alu C 130 (13 nm, untreated), Cabot SpectrAL 81 (21 nm, untreated), and Cabot SpectrAl 100 (18 nm, untreated).

[0075] Other suitable oxide nanoparticles suitable for use in combination with polymer nanoparticles may include treated or untreated titanium dioxide.Suitable commercially available titanium dioxide may include JMT-150IB manufactured by Tayca Corp., which has a volume average particle size of 15 nm, JMT2000 manufactured by Tayca Corp., which has a particle size of 15x15x40 nm, T805 manufactured by Evonik, which has a volume average particle size of about 21 nm, SMT5103 manufactured by Tayca Corporation, which has a particle size of about 40 nm, and STT-100H manufactured by Inabata America Corporation, which has an average particle size of about 40 nm.

[0076] Based on turbidity measurements, approximately 80-90% of available nanoparticles, such as polymeric or silica nanoparticles, may be associated with thermoplastic microparticles formed by melt-emulsification according to the present disclosure. Because nanoparticle loading is measured relative to the thermoplastic polymer, the amount of nanoparticles associated with the thermoplastic microparticles may be approximately 80-90% of the nanoparticle loading used in forming the thermoplastic microparticles. Higher or lower amounts of nanoparticles may be associated with the thermoplastic microparticles when higher or lower nanoparticle loadings are used in the dispersion medium.

[0077] The thermoplastic microparticles of the present disclosure may have nanoparticles, particularly polymeric nanoparticles, at least partially embedded in the outer surface of the thermoplastic microparticle. When embedding occurs, a portion of the nanoparticle structure may be located within a crater or recess in the outer surface, making it more difficult to remove the nanoparticles from the surface. It should be understood that even if substantial embedding does not occur, appropriately functionalized nanoparticles, such as hydrophobically functionalized silica nanoparticles or polymeric nanoparticles, may associate non-covalently (e.g., via van der Waals-type interactions) to promote retention of the nanoparticles on the outer surface.

[0078] Examples of thermoplastic polymers suitable for use in the present disclosure include, but are not limited to, polyamides (e.g., nylon-6, nylon-12, etc.), polyurethanes, polyethylene, polypropylene, polyacetal, polycarbonate, polyethylene or polybutylene terephthalate, glycol-modified polyethylene terephthalate or polybutylene terephthalate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polylactic acid, and other polyesters, polyethers, polyethersulfones, polyetheretherketones, polyacrylates, polymethacrylates, polyimides, acrylonitrile butadiene styrene (ABS), polyphenylene sulfide, vinyl polymers, polyarylene ethers, polyarylene sulfides, polysulfones, polyetherketones, polyaryletherketones, and the like. ketone, PAEK), polyamideimides, polyetherimides, polyetheresters, copolymers containing polyether blocks and polyamide blocks (PEBA or polyether block amides), grafted or ungrafted thermoplastic polyolefins, functionalized or unfunctionalized ethylene / vinyl monomer polymers, functionalized or unfunctionalized ethylene / vinyl monomer polymers, functionalized or unfunctionalized ethylene / alkyl (meth)acrylate, functionalized or unfunctionalized (meth)acrylic acid polymers, functionalized or unfunctionalized ethylene / vinyl monomer / alkyl (meth)acrylate terpolymers, ethylene / vinyl monomer / carbonyl terpolymers, ethylene / alkyl (meth)acrylate / carbonyl terpolymers, methyl methacrylate-butadiene-styrene (MBS) type core-shell polymers, polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (SBM) block terpolymers, chlorinated or chlorosulfonated polyethylene, polyvinylidene fluoride fluoride, PVDF), phenolic resin, poly(ethylene / vinyl acetate), polybutadiene, polyisoprene, styrene block copolymer, polyacrylonitrile, silicone, and the like, and any combination thereof.Copolymers comprising one or more of the foregoing may also be used in the present disclosure. Any of the foregoing polymers may be thermoplastic elastomers and may comprise crystalline "hard" segments and amorphous "soft" segments.

[0079] Particularly suitable examples of thermoplastic polymers for use in the present disclosure may include polyamides such as nylon-6 or nylon-12, acrylonitrile butadiene styrene, polylactic acid, polyurethanes, poly(arylene ethers), polyaryletherketones, polycarbonates, polyimides, polyphenylene sulfides, poly(arylene sulfones), polyesters such as polyethylene terephthalate or polybutylene terephthalate or glycol-modified variants, and any combination thereof.

[0080] More specific examples of suitable polyamides include, but are not limited to, polycaproamide (nylon 6, polyamide 6, or PA6), poly(hexamethylene succinamide) (nylon 46, polyamide 46, or PA46), polyhexamethylene adipamide (nylon 66, polyamide 66, or PA66), polypentamethylene adipamide (nylon 56, polyamide 56, or PA56), polyhexamethylene sebacamide (nylon 610, polyamide 610, or PA610), polyundecaamide (nylon 11, polyamide 11, or PA11), polydodecaamide (nylon 12, polyamide 12, or PA12), and polyhexamethylene terephthalate. Examples of suitable polyamides include phthalamide (nylon 6T, polyamide 6T, or PA6T), nylon 10.10 (polyamide 10.10 or PA10.10), nylon 10.12 (polyamide 10.12 or PA10.12), nylon 10.14 (polyamide 10.14 or PA10.14), nylon 10.18 (polyamide 10.18 or PA10.18), nylon 6.10 (polyamide 6.10 or PA6.10), nylon 6.18 (polyamide 6.18 or PA6.18), nylon 6.12 (polyamide 6.12 or PA6.12), nylon 6.14 (polyamide 6.14 or PA6.14), semi-aromatic polyamides, and the like, as well as any combination thereof. Copolyamides may also be used. Examples of suitable copolyamides include, but are not limited to, PA11 / 10.10, PA6 / 11, PA6.6 / 6, PA11 / 12, PA10.10 / 10.12, PA10.10 / 10.14, PA11 / 10.36, PA11 / 6.36, PA10.10 / 10.36, etc., and any combination thereof. Polyesteramides, polyetheresteramides, polycarbonateesteramides, and polyether block amides, any of which may be elastomers, may also be used in the present disclosure.

[0081] Examples of suitable polyurethanes include, but are not limited to, polyether polyurethanes, polyester polyurethanes, mixed polyether and polyester polyurethanes, and the like, and any combination thereof. Suitable polyurethanes may include elastomeric polyurethanes prepared by the condensation of an isocyanate, a polyol, and a chain extender, where the polyol provides flexibility to the polymer chain and typically constitutes the soft segment. Examples of polyurethanes suitable for use in the present disclosure include, but are not limited to, poly[4,4'-methylenebis(phenylisocyanate)-alt-1,4-butanediol / di(propylene glycol) / polycaprolactone], ELASTOLLAN® 1190A (a polyether polyurethane elastomer available from BASF), and the like, and any combination thereof.

[0082] Suitable polyesters are condensation products formed from diacids and diols, or self-condensation products of hydroxy acids such as lactic acid. Glycol-modified polyesters, such as glycol-modified polyethylene terephthalate or glycol-modified polybutylene terephthalate, may be particularly suitable for use in the present disclosure. Glycol modification can provide desirable benefits such as optical transparency and flexibility of the polymer chain.

[0083] Suitable thermoplastic polymers can be elastomeric or non-elastomeric. Some of the aforementioned examples of thermoplastic polymers can be elastomeric or non-elastomeric depending on the specific composition of the polymer. For example, polyethylene, which is a copolymer of ethylene and propylene, can be elastomeric or non-elastomeric depending on the amount of propylene present in the polymer.

[0084] Elastomeric thermoplastic polymers suitable for use in the present disclosure generally fall within one of six classes: styrenic block copolymers, thermoplastic polyolefin elastomers, thermoplastic vulcanizates (also called elastomeric alloys), thermoplastic polyurethanes, thermoplastic copolyesters, and thermoplastic polyamides (typically block copolymers containing polyamides). Specific examples of elastomeric thermoplastic polymers can be found in "Handbook of Thermoplastic Elastomers," 2nd Edition, BMW Walker and C. P. Rader, eds., Van Nostrand Reinhold, New York, 1988. Examples of suitable elastomeric thermoplastic polymers include, but are not limited to, elastomeric polyamides, polyurethanes, copolymers containing polyether blocks and polyamide blocks (PEBA or polyether block amides), methyl methacrylate-butadiene-styrene (MBS) type core-shell polymers, polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (SBM) block terpolymers, polybutadiene, polyisoprene, styrene block copolymers, and polyacrylonitrile), silicones, etc. Elastic styrenic block copolymers may include at least one block selected from the group of isoprene, isobutylene, butylene, ethylene / butylene, ethylene-propylene, and ethylene-ethylene / propylene. More specific examples of elastomeric styrenic block copolymers include, but are not limited to, poly(styrene-ethylene / butylene), poly(styrene-ethylene / butylene-styrene), poly(styrene-ethylene / propylene), styrene-ethylene / propylene-styrene), poly(styrene-ethylene / propylene-styrene-ethylene-propylene), poly(styrene-butadiene-styrene), poly(styrene-butylene-butadiene-styrene), and the like, and any combination thereof.

[0085] FIG. 1 is a flowchart of a non-limiting exemplary method 100 for producing thermoplastic microparticles according to the present disclosure. As shown, a thermoplastic polymer 105, a carrier fluid 104, and polymeric nanoparticles 106 are mixed 108 to produce a mixture 110. Optionally, other nanoparticles, such as silica nanoparticles, may be present in combination with the polymeric nanoparticles 106. The thermoplastic polymer 105, carrier fluid 104, and nanoparticles 106 may be mixed 108 in any order, with mixing and / or heating being performed. In a specific embodiment, the carrier fluid 104 may be heated above the melting point or softening temperature of the thermoplastic polymer 105 before being mixed with the other components. Alternatively, all components may be mixed together in the carrier fluid 104 and then heated above the melting point or softening temperature. The polymeric nanoparticles 106 may remain solid at the heating temperature, such that they may be disposed on the outer surface of the resulting thermoplastic microparticles after melt emulsion.

[0086] Heating above the melting or softening temperature of the thermoplastic polymer 105 can be any temperature below the decomposition or boiling point of any of the components in the molten emulsion. In non-limiting examples, heating can be performed at a temperature between about 1°C and about 50°C, or between about 1°C and about 25°C, or between about 5°C and about 30°C, or between about 20°C and about 50°C above the melting or softening temperature of the thermoplastic polymer 105. In this disclosure, melting points can be determined according to ASTM E794-06(2018) at a heating and cooling rate of 10°C / min. Softening temperatures or softening points of thermoplastic polymers can be determined according to ASTM D6090-17 unless otherwise specified. Softening points can be measured using a cup and ball apparatus available from Mettler-Toledo using a 0.50g sample at a heating rate of 1°C / min. The melting or softening temperature of the thermoplastic polymer 105 in this disclosure can range from about 50°C to about 400°C. In more specific embodiments, the heating temperature may range from about 100° C. to about 300° C. or from about 200° C. to about 250° C., provided that the thermoplastic polymer 105 melts or softens within this range.

[0087] The mixture 110 is then treated 112 by applying sufficient shear to produce liquefied droplets of the thermoplastic polymer 105 at a temperature above the melting point or softening temperature of the thermoplastic polymer 105, thereby forming a molten emulsion 114. Without being limited by theory, it is believed that, all other factors being equal, increasing the shear may decrease the size of the liquefied droplets in the dispersion medium 104. It should be understood that, in some respects, there may be a diminishing benefit in terms of increasing shear and decreasing droplet size and / or breaking up the droplets into their contents at higher shear rates. Examples of suitable mixing equipment for producing the molten emulsion 114 include, but are not limited to, extruders (e.g., continuous extruders, batch extruders, etc.), stirred reactors, blenders, reactors with in-line homogenizer systems, etc., and equipment derived therefrom.

[0088] In non-limiting examples, the liquefied droplets can have a size of about 1 μm to about 1,000 μm, or about 1 μm to about 500 μm, or about 25 μm to about 500 μm, or about 1 μm to about 200 μm, or about 1 μm to about 150 μm, or about 1 μm to about 130 μm, or about 1 μm to about 100 μm, or about 10 μm to about 150 μm, or about 10 μm to about 100 μm, or about 20 μm to about 80 μm, or about 20 μm to about 50 μm, or about 50 μm to about 90 μm. The resulting thermoplastic microparticles formed after solidification can be in a similar size range. That is, the thermoplastic microparticles in the microparticle compositions and methods of the present disclosure may have a size of about 1 μm to about 1,000 μm, or about 1 μm to about 500 μm, or about 25 μm to about 500 μm, or about 1 μm to about 200 μm, or about 1 μm to about 150 μm, or about 1 μm to about 130 μm, or about 1 μm to about 100 μm, or about 1 μm to about 200 μm, or about 10 μm to about 100 μm, or about 20 μm to about 80 μm, or about 20 μm to about 50 μm, or about 50 μm to about 90 μm. Particle size measurements can be performed by analysis of optical images or by using the built-in software of a Malvern Mastersizer 3000 Aero S instrument, which uses light scattering techniques for particle size measurement.

[0089] For light scattering techniques, glass bead control samples with diameters in the range of 15 μm to 150 μm under the trade name Quality Audit Standards QAS4002™ obtained from Malvern Analytical Ltd. can be used. Samples can be analyzed as dry powders dispersed in air using the dry powder dispersion module of a Mastersizer 3000 Aero S. Particle size can be derived using the instrument software from a plot of volume density as a function of size.

[0090] The molten emulsion 114 is then cooled 116 to solidify the liquefied droplets into solidified thermoplastic microparticles. The cooling rate can range from about 100°C / sec to about 10°C / hr, or from about 10°C / sec to about 10°C / hr, including any cooling rate therebetween. Shear can be discontinued during cooling, or can be maintained at the same or different rates during cooling. The cooled mixture 118 can then be processed 120 to separate the thermoplastic microparticles 122 from other components 124 (e.g., the carrier fluid 104, excess polymeric nanoparticles 106, etc.). Washing, filtering, and / or the like can be performed at this stage to further purify the thermoplastic microparticles 122, which comprise the thermoplastic polymer 105 and at least a portion of the polymeric nanoparticles 106 coating the exterior surfaces of the thermoplastic microparticles 122. Depending on factors such as, but not limited to, the temperature (including the cooling rate), the type of thermoplastic polymer 105, and the type and size of the polymeric nanoparticles 106, the polymeric nanoparticles 106 may become at least partially embedded within the outer surface of the thermoplastic microparticles 122 during their placement on the thermoplastic microparticles 122. Even if embedding does not occur, the polymeric nanoparticles 106 may remain tightly associated with the thermoplastic microparticles 122, facilitating their further use.

[0091] In the above, the thermoplastic polymer 105 and the dispersion medium 104 are selected so that these components are immiscible or substantially immiscible (<1 wt. % solubility) at various processing temperatures (e.g., from room temperature to temperatures at which liquefied droplets form and remain as two or more phases).

[0092] After separating the thermoplastic particulate 122 from the other components 124, further processing 126 of the thermoplastic particulate 122 may occur. In a non-limiting example, the further processing 126 may include, for example, sieving the thermoplastic particulate 122 and / or blending the thermoplastic particulate 122 with other substances to form a processed thermoplastic particulate 128. The processed thermoplastic particulate 128 may be formulated for use in a desired application, such as, in a non-limiting example, additive manufacturing.

[0093] Thermoplastic particles are approximately 0.3 g / cm 3 ~about 0.8g / cm 3 , or about 0.3 g / cm 3 ~about 0.6g / cm 3 , or about 0.4 g / cm 3 ~about 0.7g / cm 3 , or about 0.5 g / cm 3 ~about 0.6g / cm 3 , or about 0.5 g / cm 3 ~about 0.8g / cm 3 The bulk density may be

[0094] Sufficient shear force to form liquefied droplets can be applied by stirring the dispersion medium in certain embodiments of the present disclosure. In non-limiting examples, the stirring rate can range from about 50 rotations per minute (RPM) to about 1500 RPM, or from about 250 RPM to about 1000 RPM, or from about 225 RPM to about 500 RPM, or from about 1000 RPM to about 2000 RPM. The stirring rate while melting the thermoplastic polymer can be the same or different from the stirring rate used once the liquefied droplets are formed. The liquefied droplets can be stirred for a stirring time of about 30 seconds to about 18 hours or more, or from about 1 minute to about 180 minutes, or from about 1 minute to about 60 minutes, or from about 5 minutes to about 6 minutes, or from about 5 minutes to about 30 minutes, or from about 10 minutes to about 30 minutes, or from about 30 minutes to about 60 minutes.

[0095] The loading (concentration) of the thermoplastic polymer in the dispersion medium can vary over a wide range. In a non-limiting example, the loading of the thermoplastic polymer in the dispersion medium can range from about 1% to about 99% by weight, based on the weight of the dispersion medium. In more specific examples, the loading of the thermoplastic polymer can range from about 5% to about 75% by weight, or from about 10% to about 60% by weight, or from about 20% to about 50% by weight, or from about 20% to about 30% by weight, or from about 30% to about 40% by weight, or from about 40% to about 50% by weight, or from about 50% to about 60% by weight, based on the weight of the dispersion medium. The thermoplastic polymer may be present in an amount ranging from about 5% to about 60% by weight, or from about 5% to about 25% by weight, or from about 10% to about 30% by weight, or from about 20% to about 45% by weight, or from about 25% to about 50% by weight, or from about 40% to about 60% by weight, based on the combined weight of the thermoplastic polymer and the dispersion medium.

[0096] When forming thermoplastic microparticles in the presence of nanoparticles according to the present disclosure, at least a portion of the polymeric nanoparticles and / or other types of nanoparticles may be disposed as a coating or partial coating on the outer surface of the thermoplastic microparticle. The coating may, in some cases, be substantially uniformly disposed on the outer surface. As used herein with respect to a coating, the term "substantially uniform" refers to a uniform coating thickness across the surface locations covered by the nanoparticles, particularly the entire outer surface. The coating coverage on the thermoplastic microparticle may range from about 5% to about 100%, or from about 5% to about 25%, or from about 20% to about 50%, or from about 40% to about 70%, or from about 50% to about 80%, or from about 60% to about 90%, or from about 70% to about 100% of the particle's surface area. The coverage may be determined by image analysis of SEM micrographs.

[0097] Suitable dispersion media for use in the present disclosure include those in which the thermoplastic polymer and polymeric nanoparticles are substantially immiscible with the dispersion media, the dispersion media have a boiling point above the melting or softening temperature of the thermoplastic polymer, and the dispersion media have sufficient viscosity to form substantially spherical liquefied droplets when the thermoplastic polymer is melted or softened therein. Suitable dispersion media may include, for example, silicone oil, fluorinated silicone oil, perfluorinated silicone oil, polyethylene glycol, paraffin, liquid petroleum jelly, bison oil, turtle oil, soybean oil, perhydrosqualene, sweet almond oil, calophyllum oil, palm oil, parima oil, grapeseed oil, sesame oil, maize oil, rapeseed oil, sunflower oil, cottonseed oil, apricot oil, castor oil, avocado oil, jojoba oil, olive oil, cereal germ oil, orchid oil esters, oleic acid esters, lauric acid esters, stearic acid esters, fatty acid esters, higher fatty acids, fatty alcohols, fatty acid-modified polysiloxanes, fatty alcohol-modified polysiloxanes, polyoxyalkylene-modified polysiloxanes, and the like, and any combination thereof.

[0098] A suitable dispersion medium has a density of about 0.6 g / cm 3 ~Approx. 1.5g / cm 3 and the thermoplastic polymer may have a density of about 0.7 g / cm 3 ~Approx. 1.7g / cm 3 and the thermoplastic polymer may have a density similar to, lower than, or higher than the density of the carrier fluid. Blends of carrier fluids having different viscosities and / or densities can be used to achieve properties intermediate between those of the blend components.

[0099] Particularly suitable silicone oils include polysiloxanes. Exemplary silicone oils suitable for use in the present disclosure include, for example, polydimethylsiloxane (PDMS), methylphenylpolysiloxane, alkyl-modified polydimethylsiloxane, alkyl-modified methylphenylpolysiloxane, amino-modified polydimethylsiloxane, amino-modified methylphenylpolysiloxane, fluorine-modified polydimethylsiloxane, fluorine-modified methylphenylpolysiloxane, polyether-modified polydimethylsiloxane, polyether-modified methylphenylpolysiloxane, and the like, and any combination thereof.

[0100] In a non-limiting example, the dispersion medium and thermoplastic polymer may be heated to a temperature of about 200°C or higher. A suitable heating temperature may be selected based on the melting or softening temperature of the thermoplastic polymer, the boiling point of the dispersion medium, and the decomposition temperature of the polymer nanoparticles. The cooling rate after formation of the liquefied polymer droplets may be varied as desired. In some cases, cooling may occur after heating is discontinued, with heat dissipation to the surrounding environment occurring at a natural (uncontrolled) rate. In other cases, cooling at a controlled rate (e.g., gradually decreasing the heating temperature and / or using jacketed temperature control to increase or decrease the cooling rate) may be employed.

[0101] Suitable dispersion media, such as polysiloxanes, including PDMS, can have a viscosity of from about 1,000 cSt to about 150,000 cSt, or from about 1,000 cSt to about 60,000 cSt, or from about 40,000 cSt to about 100,000 cSt, or from about 75,000 cSt to about 150,000 cSt at 25° C. The viscosity of the dispersion media can be obtained from commercial sources or, if desired, can be measured by techniques known to those skilled in the art.

[0102] Separating the thermoplastic particulates from the dispersion medium can be accomplished by any of a variety of known separation techniques. The thermoplastic particulates can be separated from the dispersion medium using any of gravity settling and filtration, decantation, centrifugation, and the like. The thermoplastic particulates can then be washed with a solvent in which the dispersion medium is soluble and in which the thermoplastic particulates are insoluble during the separation process. In addition, the solvent in which the dispersion medium is soluble and in which the thermoplastic particulates are insoluble can be mixed with the dispersion medium and the thermoplastic particulates before first separating the thermoplastic particulates from the dispersion medium.

[0103] Suitable solvents for washing thermoplastic microparticles or mixing with a dispersion medium include, but are not limited to, aromatic hydrocarbons (e.g., toluene and / or xylene), aliphatic hydrocarbons (e.g., heptane, n-hexane, and / or n-octane), cyclic hydrocarbons (e.g., cyclopentane, cyclohexane, and / or cyclooctane), ethers (e.g., diethyl ether, tetrahydrofuran, diisopropyl ether, and / or dioxane), halogenated hydrocarbons (e.g., dichloroethane, trichloroethane, dichloromethane, chloroform, and / or carbon tetrachloride), alcohols (e.g., methanol, ethanol, isopropanol, and / or n-propanol), ketones (e.g., methyl ethyl ketone and / or acetone); esters (e.g., ethyl acetate, etc.), water, etc., and any combination thereof. After washing the thermoplastic microparticles, heating, vacuum drying, air drying, or any combination thereof may be performed.

[0104] At least a majority of the thermoplastic microparticles obtained according to the present disclosure may be substantially spherical in shape. More typically, about 90% or more, or about 95% or more, or about 99% or more of the thermoplastic microparticles produced by melt-emulsification according to the present disclosure may be substantially spherical in shape. In other non-limiting examples, the thermoplastic microparticles of the present disclosure may have a sphericity (circularity) of about 0.9 or greater, including about 0.90 to about 1.0, or about 0.93 to about 0.99, or about 0.95 to about 0.99, or about 0.97 to about 0.99, or about 0.98 to 1.0. Sphericity (circularity) may be measured using a Sysmex FPIA-2100 Flow Particle Image Analyzer. To determine circularity, an optical microscope image of the microparticles is taken. The perimeter (P) and area (A) of the microparticle in the plane of the microscope image are calculated (e.g., using a SYSMEX FPIA 3000 Particle Shape and Size Analyzer, available from Malvern Instruments). The circularity of the microparticle is calculated as C EA / P and C EA is the circumference of a circle with an area equivalent to the area of ​​the actual particle (A).

[0105] The thermoplastic particulates of the present disclosure may have an angle of repose of about 25° to about 45°, or about 25° to about 35°, or about 30° to about 40°, or about 35° to about 45°. Angle of repose measurements may be determined using a Hosokawa Micron Powder Characteristics Tester PT-R using ASTM D6393-14 "Standard Test Method for Characterization of Bulk Solids by Carr Index."

[0106] Thermoplastic particulates separated from the dispersing medium according to the above disclosure may be further processed to produce thermoplastic particulates suitable for the intended application. In one example, the thermoplastic particulates may be passed through a sieve or similar structure having an effective screening size larger than the average particle size of the thermoplastic particulates. For example, an exemplary screening size for processing thermoplastic particulates suitable for use in three-dimensional printing may have an effective screening size of about 150 μm. With reference to sieving, hole / screen sizes are set forth in the USA Standard Sieve (ASTM E11-17). Other screening sizes, larger or smaller, may be more suitable for thermoplastic particulates intended for other applications. Sieving may remove larger particulates that may form during the melt-emulsification process and / or may remove agglomerated particulates that may have poor flow characteristics. Generally, sieves having an effective screening size ranging from about 10 μm to about 250 μm may be used.

[0107] In addition, thermoplastic microparticles, including sieved thermoplastic microparticles, can be mixed with one or more additional components, such as flow aids, fillers, or other substances intended to adjust the properties of the thermoplastic microparticles for the intended application. The mixing of the additional components with the thermoplastic microparticles can be carried out by dry blending techniques. Suitable examples of flow aids (e.g., carbon black, graphite, silica, etc.) and similar substances are well known to those skilled in the art. Such flow aids differ from the nanoparticles involved in melt emulsification because the flow aids do not adhere firmly to the surface of the thermoplastic microparticles when dry blending is carried out.

[0108] In certain applications, the particulate compositions disclosed herein may be used in additive manufacturing processes, particularly those using selective laser sintering or other powder bed fusion processes to promote particulate consolidation. The additive manufacturing method of the present disclosure may include providing a particulate composition of the present disclosure (a particulate composition comprising a plurality of thermoplastic particulates comprising a thermoplastic polymer and polymeric nanoparticles disposed on the outer surfaces of the thermoplastic particulates), depositing the particulate composition layer by layer onto a powder bed, and heating a portion of the powder bed to consolidate a portion of the thermoplastic particulates into a consolidated part having a specific shape. Upon powder bed fusion, the nanoparticles may remain associated with the consolidated portion. Specifically, the consolidated part may include a thermoplastic matrix formed by consolidation of the thermoplastic particulates and at least polymeric nanoparticles mixed with the thermoplastic matrix.

[0109] In certain process configurations, consolidation of the thermoplastic particulate may be performed using selective laser sintering. Suitable conditions for performing selective laser sintering or other powder bed particulate consolidation processes to form consolidated parts are not considered particularly limiting. Lasers suitable for performing selective laser sintering may include both continuous wave lasers and pulsed wavelength lasers, and can provide the consolidated part with the energy necessary to promote consolidation of the thermoplastic particulate. CO2 lasers are commonly used to promote consolidation of thermoplastic particulate during additive manufacturing due to the high absorption coefficient of polymers at the CO2 laser emission wavelength. The operating conditions of a CO2 laser or similar laser selected to promote particulate consolidation can be selected to achieve the desired degree of particulate consolidation. Standard laser settings (e.g., power, scan speed, bed temperature, etc.) for promoting particulate consolidation may be selected based on the knowledge of those skilled in the art. The selection of specific conditions for performing selective laser sintering or similar particulate consolidation techniques can be influenced by non-limiting factors, such as the type of thermoplastic polymer used, the size and composition of the thermoplastic particulate, the type of printed object being produced, and the intended use conditions of the printed object. The selection of sintering conditions can affect the porosity obtained after particulate consolidation, in non-limiting examples. Preferably, the thermoplastic matrix obtained from particulate consolidation can have a porosity of about 10% or less, or about 5% or less, or about 2% or less, or about 1% or less.

[0110] Examples of printed objects that can be formed using the particulate compositions disclosed herein include, but are not limited to, containers (e.g., for food, beverages, cosmetics, personal care compositions, medical, etc.), shoe soles, toys, furniture parts, decorative household items, plastic gears, screws, nuts, bolts, cable ties, medical articles, prosthetics, orthopedic implants, generating artifacts to aid learning in education, 3D anatomical models to aid surgery, robotics, biomedical devices (orthotics), household appliances, dental, automotive and aircraft / aerospace parts, electronics, sporting goods, and the like.

[0111] Embodiments disclosed herein include the following.

[0112] A. Composition Comprising Powdered Particulates. The particulate composition comprises a plurality of thermoplastic particulates comprising a thermoplastic polymer and a plurality of polymeric nanoparticles disposed on an exterior surface of the thermoplastic particulates, the polymeric nanoparticles comprising a crosslinked fluorinated polymer.

[0113] B. A method for forming a printed object by particulate consolidation, the method including providing a particulate composition of A, depositing the particulate composition layer by layer onto a powder bed, and heating a portion of the powder bed to consolidate a portion of the thermoplastic particulate into a consolidated part having a particular shape.

[0114] A consolidated part prepared by the method of CB. The consolidated part comprises a thermoplastic matrix formed by consolidation of thermoplastic particulates and polymeric nanoparticles mixed with the thermoplastic matrix. D. A method for forming powder particulates. The method includes combining a thermoplastic polymer and polymeric nanoparticles with a dispersing medium at a heating temperature equal to or greater than the melting or softening temperature of the thermoplastic polymer and less than the melting, softening, or decomposition temperature of the polymeric nanoparticles, wherein the thermoplastic polymer and polymeric nanoparticles are substantially immiscible in the dispersing medium at the heating temperature, and the polymeric nanoparticles comprise a crosslinked fluorinated polymer; applying a shear force sufficient to disperse the thermoplastic polymer as liquefied droplets in the dispersing medium at the heating temperature in the presence of the polymeric nanoparticles; after the liquefied droplets are formed, cooling the dispersing medium to a temperature at which at least solidified thermoplastic particulates are formed, wherein the thermoplastic particulates comprise a thermoplastic polymer and at least a portion of the polymeric nanoparticles disposed on the outer surfaces of the thermoplastic particulates; and separating the thermoplastic particulates from the dispersing medium.

[0115] Each of embodiments A, B, C, and D may have one or more of the following additional elements in any combination.

[0116] Element 1: The crosslinked fluorinated polymer comprises a fluorinated (meth)acrylic monomer and a divinyl crosslinker.

[0117] Element 2: The fluorinated (meth)acrylic monomer comprises 2,2,2-trifluoroethyl (meth)acrylate and the divinyl crosslinker comprises divinylbenzene.

[0118] Element 3: The crosslinked fluorinated polymer further comprises an ethylenically unsaturated comonomer different from the fluorinated (meth)acrylic monomer.

[0119] Element 4: The particulate composition further comprises inorganic nanoparticles disposed on the outer surface of the thermoplastic particulate, the inorganic nanoparticles comprising a plurality of oxide nanoparticles, carbon black, or any combination thereof.

[0120] Element 5: The oxide nanoparticles include silica nanoparticles.

[0121] Element 6: The thermoplastic particulates comprise from about 0.01% to about 10% by weight of nanoparticles, measured relative to the thermoplastic polymer.

[0122] Element 7: The thermoplastic particles are substantially spherical and have a diameter D in the range of about 1 μm to about 1,000 μm. 50 It has.

[0123] Element 8: The polymer nanoparticles range in size from about 5 nm to about 500 nm.

[0124] Element 9: Heating is achieved by selective laser sintering.

[0125] Element 10: The polymer nanoparticles remain associated with the consolidated part.

[0126] Element 11: The polymer nanoparticles are obtained by emulsion polymerization.

[0127] Element 12: The method further includes combining inorganic nanoparticles with a carrier fluid, wherein the inorganic nanoparticles comprise a plurality of oxide nanoparticles, carbon black, or any combination thereof, and at least a portion of the inorganic nanoparticles are disposed on an outer surface of the thermoplastic particulate. Element 13: The carrier fluid includes a silicone oil.

[0128] As non-limiting examples, exemplary combinations applicable to A, B, C, and D include, but are not limited to, 1 and 3; 1-3; 1 and 4; 1, 4, and 5; 1 and 6; 1 and 7; 1 and 8; 4 and 5; 4 and 6; 4 and 7; 4 and 8; 6 and 7; 6 and 8; and 7 and 8.

[0129] To facilitate a better understanding of the present disclosure, the following examples of preferred or representative embodiments are given. The following examples should not be read to limit or define the scope of the present invention. [Example]

[0130] In the following examples, powder streams of thermoplastic particulates were characterized through sieving and angle of repose. Sieving was performed using a 150 μm USA standard sieve (ASTM E11) with no specific conditions or force duration. Angle of repose measurements were performed using a Hosokawa Micron Powder Characteristics Tester PT-R using ASTM D6393-14, "Standard Test Method for Characterization of Bulk Solids by Carr Index."

[0131] The mean particle size and particle size distribution of thermoplastic particulates were determined by light scattering using a Malvern Mastersizer 3000 Aero S particle size analyzer. For such light scattering techniques, glass bead control samples with diameters ranging from 15 μm to 150 μm under the trade name Quality Audit Standards QAS4002™, obtained from Malvern Analytical Ltd., can be used. Samples can be analyzed as dry powders dispersed in air using the Mastersizer 3000 Aero S instrument's dry powder dispersion module. Particle size can be derived using the instrument software from a plot of volume density as a function of size.

[0132] The average particle size of polymer nanoparticles was measured by dynamic light scattering using a Nanotrac 252 instrument (MicroTrac, Inc.). This instrument uses laser light scattering technology to measure the Doppler-shifted light generated by each particle in motion (Brownian motion). The signal generated by these shifts is proportional to the particle size. The signal is mathematically converted to particle size and size distribution by the instrument's software. Analysis can be performed using an external probe or by inserting a probe into a fixed sample chamber. For this light scattering technique, a NIST polystyrene nanosphere reference sample with a diameter in the range of 15 nm to 150 nm can be used, available from Microtrac under the trade name NIST Traceable Reference Material for Nanotrac Particle Size Analyzers.

[0133] In the following examples, weight percentages are measured relative to the thermoplastic polymer unless otherwise specified.

[0134] Formation of polymer nanoparticles by emulsion polymerization. In a 2 L Buchi reactor, 6.5 g of CALFOAM® SLS-30 surfactant (30% solids sodium lauryl sulfate, Pilot Chemical) was added to 816 g of deionized water. The reactor was deoxygenated by passing a stream of nitrogen through the reaction mixture and then ramping to 77°C. In a separate 1 L glass vessel, a monomer emulsion was prepared by mixing together 223.6 g of trifluoroethyl methacrylate (TFEMA), 95.8 g of divinylbenzene (DVB), 6.5 g of CALFOAM® SLS-30 surfactant (30% solids), and 416 g of deionized water. A seed weight of 37.1 g was removed from the monomer emulsion and pumped into the 2 L reactor at 77°C. An initiator solution prepared from 1.22 g of ammonium persulfate in 34.3 g of deionized water was then added over 20 minutes to the reactor containing the seed emulsion. The remaining monomer emulsion was then fed into the reactor over 120 minutes. After adding half of the monomer emulsion, the stirring speed was increased. After adding all of the monomer emulsion, the reaction mixture was maintained at 77°C for 1 hour, then increased to 87°C for 2 hours and held at this temperature for 1 hour to reduce residual monomer after emulsion polymerization. The resulting latex emulsion contained 20% percent solids with an average particle size of 95 nm (spread: 8 nm to 6.54 μm) and a melting point by TGA of 290.6°C. The latex was spray-dried to isolate the fluorinated polymer nanoparticles for subsequent melt-emulsification.

[0135] Example 1: Polyurethane microparticles coated with 1.0 wt% fluorinated polymer nanoparticles. A 2-L Buchi reactor was filled with PDMS oil having a viscosity of 30,000 cSt and premixed with 1.0 wt% fluorinated polymer nanoparticles prepared as described above. Polyurethane pellets (ELASTOLAN 1190A10, BASF) were then added at 40 wt% relative to the PDMS oil. The reactor was stirred at 200 rpm for 10 minutes under N2 purge and then heated to 240°C at a rate of 3.6°C / min. When the temperature reached approximately 225°C, the stirring speed was increased to 500 rpm. The molten dispersion was mixed at 500 rpm for an additional 30 minutes after the temperature reached 235°C with the N2 turned off. After particle formation occurred, the hot slurry was discharged into a tray and allowed to cool to room temperature. The resulting polyurethane microparticles were reslurried four times in heptane and filtered onto a Whatman #1 90 mm filter paper to remove the PDMS oil. The polyurethane microparticles had a D of 81.8 microns (span=1.13) after drying to remove the solvent. 50 The angle of repose was 29.8°. Figure 2 is a scanning electron microscope image of the polyurethane microparticles prepared according to Example 1. Figure 3 is a graph showing the particle size distribution of the polyurethane microparticles prepared according to Example 1.

[0136] For SLS printing, the microparticles were further screened through a 250 μm sieve and then printed using a Snow White printer at 108°C and 70% laser power.

[0137] Example 2: Polyurethane microparticles coated with 1.5 wt% fluorinated polymer nanoparticles. Example 1 was repeated except that 1.5 wt% fluorinated polymer nanoparticles were used during the melt emulsification. The resulting polyurethane microparticles had a D of 42.7 microns (span=0.89) after drying to remove the solvent. 50 The powder was screened through a 150 μm sieve and had an angle of repose of 31.0°.

[0138] Example 3: Polyurethane microparticles coated with 0.75 wt% fluorinated polymer nanoparticles. Example 1 was repeated except that 0.75 wt% fluorinated polymer nanoparticles were used during the melt emulsification. The resulting polyurethane microparticles had a D of about 81.5 microns (span=0.79) after drying to remove the solvent. 50 and was screened through a 150 μm sieve. The angle of repose was 28.3°.

[0139] Example 4: Polyamide microparticles coated with 1.0 wt% fluorinated polymer nanoparticles. A 2-L Buchi reactor was charged with PDMS oil having a viscosity of 40,000 cSt (a blend of 41.5%, 30,000 cSt, and 58.5%, 60,000 cSt PDMS oils) and premixed with 1.0 wt% fluorinated polymer nanoparticles prepared as described above. Polyamide-12 pellets (RTP, Winona, Minnesota) were then added at 30 wt% relative to the PDMS oil. The reactor was stirred at 200 rpm under N2 purge for 10 minutes and then heated to 250°C at a rate of 3.6°C / min. When the temperature reached approximately 230°C, the stirring speed was increased to 650 rpm. The molten dispersion was mixed at 650 rpm for an additional 60 minutes after the temperature reached 235°C. The heating and N2 purge were then discontinued, and the stirring speed was reduced to 50 rpm. After cooling to room temperature, the slurry was discharged onto a tray. The resulting polyamide microparticles were reslurried four times in heptane and filtered onto a Whatman #1 90 mm filter paper to remove the PDMS oil. The polyamide microparticles had a D of approximately 58.6 microns (span = 0.983) after drying to remove the solvent. 50 The two batches of particles were mixed and screened through a 250 μm sieve for angle of repose measurement. The angle of repose was 26.2°. Figure 4 is a scanning electron microscope image of the polyamide microparticles prepared according to Example 4. Figure 5 is a graph showing the particle size distribution of the polyamide microparticles prepared according to Example 4.

[0140] The mixed batch of powder particles was then used for SLS printing using a Snow White printer. Good printing performance was demonstrated in a single layer by sintering at a temperature set point of 138°C and 40% laser power.

[0141] Example 5: Polyamide microparticles coated with 1.5 wt% fluorinated polymer nanoparticles. Example 4 was repeated except that 1.5 wt% fluorinated polymer nanoparticles were used during the melt emulsification and the PDMS oil had a viscosity of 30,000 cSt. The resulting polyamide microparticles had a D of 45.1 microns (span=1.59) after drying to remove the solvent. 50 and was screened through a 150 μm sieve. The angle of repose was 27.6°.

[0142] 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.

[0143] 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.

[0144] 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 of the element it introduces.

[0145] One or more exemplary embodiments are presented herein. For clarity, not all features of a physical implementation are described or depicted 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.

[0146] 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 illustratively disclosed embodiments preferably may 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 microparticle composition, A particulate composition comprising a plurality of thermoplastic particulates comprising a thermoplastic polymer and a plurality of polymeric nanoparticles disposed on an outer surface of the thermoplastic particulates, the polymeric nanoparticles comprising a crosslinked fluorinated polymer. [2] The particulate composition according to [1], wherein the crosslinked fluorinated polymer comprises a fluorinated (meth)acrylic monomer and a divinyl crosslinking agent. [3] The fine particle composition according to [2], wherein the fluorinated (meth)acrylic monomer comprises 2,2,2-trifluoroethyl (meth)acrylate, and the divinyl crosslinking agent comprises divinylbenzene. [4] The particulate composition according to [2], wherein the crosslinked fluorinated polymer further contains an ethylenically unsaturated comonomer different from the fluorinated (meth)acrylic monomer. [5] The particulate composition according to [1], further comprising inorganic nanoparticles disposed on the outer surface of the thermoplastic particulate, wherein the inorganic nanoparticles comprise a plurality of oxide nanoparticles, carbon black, or any combination thereof. [6] The microparticle composition according to [5], wherein the oxide nanoparticles include silica nanoparticles. [7] The microparticle composition according to [1], wherein the thermoplastic microparticles contain about 0.01% by weight to about 10% by weight of polymer nanoparticles when measured relative to the thermoplastic polymer. [8] The thermoplastic microparticles are substantially spherical and have a D in the range of about 1 μm to about 1,000 μm. 50 The microparticle composition according to [1] above, [9] The fine particle composition according to [1], wherein the polymer nanoparticles have a size range of about 5 nm to about 500 nm.

[10] A method comprising: Providing the microparticle composition according to [1] above; depositing the particulate composition layer by layer onto a powder bed; and heating a portion of the powder bed to consolidate a portion of the thermoplastic particulates into a consolidated part having a particular shape.

[11] The method according to

[10] , wherein the heating is performed by selective laser sintering.

[12] The method of

[10] , wherein the polymeric nanoparticles remain associated with the consolidated part.

[13] A consolidated part prepared by the method according to

[10] , a thermoplastic matrix formed by the consolidation of thermoplastic particulates; and polymer nanoparticles mixed with the thermoplastic matrix.

[14] A method comprising: combining a thermoplastic polymer and polymeric nanoparticles with a dispersion medium at a heating temperature equal to or greater than the melting or softening temperature of the thermoplastic polymer and less than the melting, softening, or decomposition temperature of the polymeric nanoparticles; combining the thermoplastic polymer and the polymeric nanoparticles, wherein the thermoplastic polymer and the polymeric nanoparticles are substantially immiscible in the dispersion medium at the heating temperature, and the polymeric nanoparticles comprise a crosslinked fluorinated polymer; applying sufficient shear force to disperse the thermoplastic polymer as liquefied droplets in the dispersion medium at the heated temperature in the presence of the polymeric nanoparticles; cooling the dispersion medium after liquefied droplets are formed to at least a temperature at which solidified thermoplastic microparticles are formed, the thermoplastic microparticles comprising the thermoplastic polymer and at least a portion of the polymeric nanoparticles disposed on an outer surface of the thermoplastic microparticles; and separating the thermoplastic particulates from the dispersion medium.

[15] The method according to

[14] , wherein the crosslinked fluorinated polymer comprises a fluorinated (meth)acrylic monomer and a divinyl crosslinker.

[16] The method according to

[15] , wherein the fluorinated (meth)acrylic monomer comprises 2,2,2-trifluoroethyl (meth)acrylate, and the divinyl crosslinker comprises divinylbenzene.

[17] The method according to

[15] , wherein the crosslinked fluorinated polymer further comprises an ethylenically unsaturated comonomer different from the fluorinated (meth)acrylic monomer.

[18] The method further comprises combining inorganic nanoparticles with the dispersion medium, wherein the inorganic nanoparticles comprise a plurality of oxide nanoparticles, carbon black, or any combination thereof; 15. The method of claim 14, wherein at least a portion of the inorganic nanoparticles are disposed on the outer surface of the thermoplastic particulate.

[19] The method according to

[18] , wherein the oxide nanoparticles include silica nanoparticles.

[20] The method according to

[14] , wherein the thermoplastic microparticles comprise from about 0.01% by weight to about 10% by weight of polymer nanoparticles when measured relative to the thermoplastic polymer.

Claims

1. 1. A method comprising: providing a particulate composition comprising a plurality of thermoplastic particulates having a circularity of 0.9 or greater and comprising a thermoplastic polymer; and a plurality of polymeric nanoparticles disposed on an outer surface of the thermoplastic particulates, the polymeric nanoparticles comprising a crosslinked fluorinated polymer; depositing the particulate composition layer by layer onto a powder bed; and heating a portion of the powder bed to consolidate a portion of the thermoplastic particulates into a consolidated part having a particular shape.

2. The method of claim 1 , wherein the heating is performed by selective laser sintering.

3. The method of claim 1 , wherein the polymeric nanoparticles remain associated with the consolidated part.

4. 10. A consolidated part prepared by the method of claim 1, comprising: a thermoplastic matrix formed by the consolidation of thermoplastic particulates; and polymer nanoparticles mixed with the thermoplastic matrix.

5. 1. A method for additive manufacturing, comprising: combining a thermoplastic polymer and polymeric nanoparticles with a dispersion medium at a heating temperature equal to or greater than the melting or softening temperature of the thermoplastic polymer and less than the melting, softening, or decomposition temperature of the polymeric nanoparticles; combining the thermoplastic polymer and the polymeric nanoparticles, wherein the thermoplastic polymer and the polymeric nanoparticles are immiscible in the dispersion medium at the heating temperature, and the polymeric nanoparticles comprise a crosslinked fluorinated polymer; applying shear force to disperse the thermoplastic polymer as liquefied droplets in the dispersion medium at the heated temperature in the presence of the polymer nanoparticles; cooling the dispersion medium to a temperature after the liquefied droplets are formed to form thermoplastic microparticles, at least in a solidified state, having a circularity of 0.9 or greater and comprising the thermoplastic polymer, wherein at least a portion of the polymer nanoparticles are disposed on an outer surface of the thermoplastic microparticles; and separating the thermoplastic particulates from the dispersion medium.

6. The method of claim 5 , wherein the crosslinked fluorinated polymer comprises a fluorinated (meth)acrylic monomer and a divinyl crosslinker.

7. The method of claim 6, wherein the fluorinated (meth)acrylic monomer comprises 2,2,2-trifluoroethyl (meth)acrylate and the divinyl crosslinker comprises divinylbenzene.

8. 7. The method of claim 6, wherein the crosslinked fluorinated polymer further comprises an ethylenically unsaturated comonomer different from the fluorinated (meth)acrylic monomer.

9. further comprising combining inorganic nanoparticles with the dispersion medium, wherein the inorganic nanoparticles comprise a plurality of oxide nanoparticles, carbon black, or any combination thereof; The method of claim 5 , wherein at least a portion of the inorganic nanoparticles are disposed on the outer surface of the thermoplastic particulate.

10. The method of claim 9 , wherein the oxide nanoparticles comprise silica nanoparticles.

11. 6. The method of claim 5, wherein the thermoplastic microparticles comprise from 0.01% to 10% by weight of polymeric nanoparticles as measured relative to the thermoplastic polymer.

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