Compositions and methods related to in-situ crosslinking of polyamides during additive manufacturing

Abstract

To provide a composition and method that allow in-situ cross-linking of polyamide during a consolidation process of addition production.SOLUTION: A particle containing unsaturated polyamide and initiator can be produced. The particles are used in an addition production method that includes depositing the particles on a surface, optionally in combination with other thermoplastic polymer particles, and after deposition, heating at least a portion of the particles to promote their consolidation and cross-linking of the unsaturated polyamide, thereby forming a consolidation containing cross-linked polyamide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure includes compositions, synthesis methods, and articles related to polyamides that are crosslinked during an additive manufacturing process.

Background Art

[0002] Thermoplastic polymers are often used to make extruded objects such as films, bags, particles, and filaments. An example of a thermoplastic polymer is polyamide. Polyamides such as nylon are off-white polymers having the ability to withstand high or low temperatures without degrading their physical properties. Thus, objects formed of polyamide can be used in demanding applications such as power tools, automotive parts, gears, and electrical appliance parts. Additive manufacturing is increasingly being used to produce such objects.

[0003] Generally, additive manufacturing broadly describes a technique for constructing three-dimensional objects by adding many layers of material. The addition of layers can be accomplished using filaments or powders. In the case of filaments, the filament material is melted, extruded, and deposited in layers to produce the desired object. Such a method can be referred to as fused filament fabrication (FFF). Selective laser sintering (SLS) is another additive manufacturing method in which a thin layer of powder (typically microparticles) is applied as a layer. Selected regions within this layer are fused by exposure to laser light (e.g., CO2 laser light) to build a solid object supported by the unused powder.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Polyamide is one of the most common polymers used in additive manufacturing due to its flow characteristics, lower cost than other polymers, and desirable sintering window. However, the physical properties required for objects produced by additive manufacturing may exceed the properties of polyamide.

[0005] This disclosure includes compositions, synthesis methods, and articles related to polyamides that are crosslinked during an additive manufacturing process. That is, the compositions and methods described herein enable in-situ crosslinking of polyamides during the consolidation step of additive manufacturing.

[0006] Disclosed herein are compositions comprising particles that include an unsaturated polyamide and an initiator.

[0007] Disclosed herein is a method that includes depositing the aforementioned composition, optionally in combination with other thermoplastic polymer particles, onto a surface and, after deposition, heating at least a portion of the particles to promote their consolidation and crosslinking of the unsaturated polyamide, thereby forming a consolidated body that includes crosslinked polyamide.

[0008] Disclosed herein is a method that includes mixing a mixture that includes an unsaturated polyamide, a dispersion medium immiscible with the unsaturated polyamide, and optionally an emulsifying stabilizer, at a temperature above the melting point or softening temperature of the unsaturated polyamide and at a shear rate high enough to disperse the unsaturated polyamide in the dispersion medium, and cooling the mixture to below the melting point or softening temperature of the unsaturated polyamide to form unsaturated polyamide particles that include the unsaturated polyamide and, if present, an emulsifying stabilizer associated with the outer surface of the unsaturated polyamide particles.

Brief Description of the Drawings

[0009] The following figures are included to illustrate certain aspects of the present disclosure and should not be viewed as an exclusive configuration. The disclosed subject matter is capable of considerable modification, variation, combination, and equivalents in form and function as would be apparent to those skilled in the art having the benefit of this disclosure.

[0010]

Figure 1

[0011] The present disclosure includes compositions, synthesis methods, and articles related to polyamides that are crosslinked during an additive manufacturing process. More specifically, the polyamide synthesis described herein uses one or more polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond. The resulting polyamides are referred to herein as unsaturated polyamides and contain unsaturated aliphatic carbon-carbon bonds.

[0012] The present disclosure also relates to particles containing unsaturated polyamides and related methods. The particles are referred to herein as unsaturated polyamide particles. The unsaturated polyamide particles may be doped with an initiator. Methods for preparing unsaturated polyamide particles doped with an initiator and methods for using unsaturated polyamide particles doped with an initiator in additive manufacturing are described herein. During additive manufacturing, more specifically during densification, the initiator can cause crosslinking between the unsaturated polyamides. Crosslinking of the polyamides can impart higher heat resistance, improved wear resistance, and other physical properties that can be improved compared to the polyamides when not crosslinked. Thus, the improved properties may be imparted to articles and objects produced by an additive manufacturing method.

[0013] Furthermore, in additive manufacturing methods, due to the low melt flow rate, it can be difficult to operate directly with highly crosslinked polyamides. Thus, particles containing highly crosslinked polyamides may not be effectively consolidated, or filaments containing highly crosslinked polyamides may have suitable melting and flow characteristics. Advantageously, the compositions and methods of the present disclosure use in-situ crosslinking of unsaturated polyamides. Thus, during the additive manufacturing method, the desired melting and flow characteristics of the unsaturated polyamide can be utilized to provide good consolidation of the particles, while the temperature and / or laser wavelength encountered in the additive manufacturing method can initiate crosslinking of the unsaturated polyamide by activation of an initiator. This can allow sufficient time for the unsaturated polyamide to melt and / or consolidate in the desired location and for crosslinks to form, such that the resulting article or object is actually formed from the crosslinked polyamide. Thus, the resulting article can have improved physical properties of the crosslinked polyamide. Definitions and Test Methods

[0014] As used herein, the term "immiscibility" refers to a mixture of two or more components that, when combined, form two or more phases having a solubility in each other of less than 5 wt% at ambient pressure at room temperature or, if solid at room temperature, at the melting point of the components. For example, polyethylene oxide having a molecular weight of 10,000 g / mol is solid at room temperature and has a melting point of 65°C. Thus, if a material that is liquid at room temperature and the polyethylene oxide have a solubility of less than 5 wt% at 65°C, the polyethylene oxide is immiscible with the material.

[0015] As used herein, the term "thermal initiator" refers to a molecule that produces reactive species (e.g., free radicals, cations, or anions) when exposed to heat. The temperature required to activate a thermal initiator depends on the molecule and can be readily achieved by reference and / or simple experimentation by one of ordinary skill in the art.

[0016] As used herein, the term "photoinitiator" refers to a molecule that generates reactive species (e.g., free radicals, cations, or anions) when exposed to electromagnetic radiation (e.g., ultraviolet light, visible light, etc., and any combination thereof).

[0017] As used herein, the term "initiator" generally refers to one or more thermal initiators, one or more photoinitiators, or a combination of one or more thermal initiators and one or more photoinitiators.

[0018] As used herein, the term "polyamide monomer" refers to a monomer that forms a polyamide.

[0019] As used herein, the term "polyacid" when referring to a compound refers to a compound having two or more carboxylic acid moieties. In this specification, an anhydride moiety is considered a carboxylic acid moiety because the anhydride ring-opens to a carboxylic acid during synthesis.

[0020] As used herein, the term "polyamine" when referring to a compound refers to a compound having two or more amine moieties.

[0021] As used herein, the term "amino acid" when referring to a compound refers to a compound having one or more carboxylic acid moieties and one or more amine moieties. Here too, an anhydride moiety is considered a carboxylic acid moiety because the anhydride ring-opens to a carboxylic acid during synthesis.

[0022] When a polymer is referred to in terms of -mer units (e.g., polyamide monomers), one of ordinary skill in the art will understand that the -mer units are in the polymerized form in the polymer.

[0023] As used herein, the term "thermoplastic polymer" refers to a plastic polymer material that reversibly softens and hardens upon heating and cooling. Thermoplastic polymers include thermoplastic elastomers.

[0024] As used herein, the term "elastomer" refers to a copolymer that includes a crystalline "hard" portion and an amorphous "soft" portion. In the case of polyurethane, the crystalline portion may include a part of the polyurethane that includes urethane functionality and an optional chain extender, and the soft portion may include, for example, a polyol.

[0025] As used herein, the term "polyurethane" refers to the polymer reaction product between a diisocyanate, a polyol, and any chain extender.

[0026] As used herein, the term "oxide" refers to both metal oxides and non-metal oxides. For the purposes of this disclosure, silicon is considered to be a metal.

[0027] As used herein, the terms "associated", "associating", and their grammatical variations between an emulsifier and a surface are used to refer to the chemical bonding and / or physical adhesion of the emulsifier to the surface. Without being limited by theory, the association described herein between a polymer and an emulsifier is believed to be primarily physical adhesion by hydrogen bonding and / or other mechanisms. However, there may be some degree of chemical bonding occurring.

[0028] As used herein, the term "embedded" with respect to the surface of nanoparticles and polymer particles means that the nanoparticles extend at least partially into the surface such that the polymer is in contact with the nanoparticles to a greater extent than would occur if the nanoparticles were simply deposited on the surface of the polymer particles.

[0029] As used herein, the term "dry blend" refers to mixing components such that each component has less than 10% by weight of a solvent and / or dispersant (e.g., water, methanol, acetone, etc., and any combination thereof) in which the component is present.

[0030] As used herein, the term "wet blend" refers to mixing components where at least one component is in the presence of 10% or more by weight of a solvent and / or dispersant (e.g., water, methanol, acetone, etc., and any combination thereof) based on the weight of the component.

[0031] Hereinafter in this specification, D10, D50, D90, and diameter span are mainly used to describe particle size. As used herein, the term "D10" refers to the diameter such that 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 "D50" refers to the diameter such that 50% of the sample (by volume, unless otherwise specified) consists of particles having a diameter less than that diameter value. As used herein, the term "D90" refers to the diameter such that 90% of the sample (by volume, unless otherwise specified) consists of particles having a diameter less than that diameter value.

[0032] As used herein, the terms "diameter span", "span", and "span size" when referring to diameter provide an indication of the spread of the particle size distribution and are calculated as (D90 - D10) / D50 (again, each D value is volume-based unless otherwise stated).

[0033] Particle size can be determined by light scattering techniques using a MASTERSIZER (trademark) 3000 from Malvern or by analysis of optical digital micrographs. Unless otherwise stated, light scattering techniques are used to analyze particle size.

[0034] Regarding the light scattering technique, the control sample was glass beads having a diameter in the range of 15 μm to 150 μm of the trademark Quality Audit Standards QAS4002 (trademark) obtained from Malvern Analytical Ltd. Unless otherwise specified, the sample was analyzed as a dry powder. The analyzed particles were dispersed in air and analyzed using an AERO S dry powder dispersion module together with a MASTERSIZER (trademark) 3000. The particle size was derived using the instrument software from a plot of volume density as a function of size.

[0035] The particle size measurement and diameter span can also be determined by optical digital microscopy. The optical images are obtained using a Keyence VHX-2000 digital microscope using version 2.3.5.1 software (system version 1.93) for particle size analysis.

[0036] As used herein, when referring to sieves, the pore / screen size is described in U.S.A. Standard Sieve (ASTM E11-17).

[0037] As used herein, the terms "circularity" and "sphericity" for particles refer to how close the particles are to a perfect sphere. To determine the circularity, an optical microscope image of the particle is taken. The perimeter length (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 the particle is C EA / P, and C EA is the circumference of a circle having an area corresponding to the area of the actual particle (A).

[0038] As used herein, the term "shearing force" refers to agitation or a similar process that induces mechanical agitation in a fluid.

[0039] As used herein, the term "aspect ratio" is used to refer to the ratio of length divided by width, where the length is greater than the width.

[0040] Unless otherwise specified, the melting point of the polymer is determined using a heating and cooling rate of 10 °C / min in accordance with ASTM E794-06(2018).

[0041] Unless otherwise specified, the softening temperature or softening point of the polymer is determined in accordance with ASTM D6090-17. The softening temperature can be measured using a 0.50-gram sample at a heating rate of 1 °C / min using a cup-and-ball apparatus available from Mettler-Toledo.

[0042] The angle of repose is a measure of the flowability of the powder. The measured value of the angle of repose was determined using a Hosokawa Micron Powder Characteristics Tester PT-R using ASTM D6393-14, "Standard Test Method for Bulk Solids Characterized by Carr Indices".

[0043] The Hausner ratio (H r ) is a measure of the flowability of the powder and is calculated by H r = ρ tap / ρ bulk , where ρ bulk is the bulk density according to ASTM D6393-14 and ρ tap is the tapped density according to ASTM D6393-14.

[0044] As used herein, the viscosity of the dispersion medium is the kinematic viscosity at 25 °C measured in accordance with ASTM D445-19, unless otherwise specified. For commercially obtained dispersion media (e.g., PDMS oil), the kinematic viscosity data cited herein is provided by the manufacturer, whether measured in accordance with the aforementioned ASTM or another standard measurement technique. Unsaturated polyamide

[0045] Unsaturated polyamides can be synthesized by various methods in which at least one monomer contains at least one unsaturated aliphatic carbon-carbon bond. Examples of methods include, but are not limited to, condensation polymerization (also referred to herein as polycondensation) and ring-opening polymerization. Without being bound by theory, the synthesis method may preferably be carried out at a temperature at which the unsaturated bond is not involved in the polymerization. This temperature varies based on the monomers used, but preferably, the unsaturated polyamide is synthesized at a temperature of 100 °C or lower.

[0046] As used herein, these polymerizations are carried out in the presence of one or more polyamine monomers, one or more polyacid monomers, one or more amino acid monomers, or any combination thereof, and at least one of any of these monomers contains at least one unsaturated aliphatic carbon-carbon bond.

[0047] Some examples of polycondensation and ring-opening polymerization reactions are presented below, followed by non-limiting examples of polyamide monomers suitable for use in one or more of the reactions. The following examples are not limited to the scope of polyamide monomers.

[0048] Scheme 1 shows the polycondensation reaction of an amino acid polyamide monomer, where C-1 represents the portion of the amino acid polyamide monomer between the carboxylic acid and amine moieties involved in the polycondensation reaction. With respect to the compositions and methods of the present disclosure, C-1 in this example contains at least one unsaturated aliphatic carbon-carbon bond. Scheme 2 is a non-limiting example of Scheme 1.

Chemical formula

[0049] Scheme 3 shows the polycondensation reaction between two amino acid polyamide monomers, where C-1 and C-2 represent the portions of each amino acid polyamide monomer between the carboxylic acid and amine moieties involved in the polycondensation reaction. With respect to the compositions and methods of the present disclosure, C-1, C-2, or both C-1 and C-2 may contain at least one unsaturated aliphatic carbon-carbon bond.

Chem.

[0050] Scheme 4 is a non-limiting example of Scheme 3, where C-1 does not contain an unsaturated aliphatic carbon-carbon bond and C-2 contains an unsaturated aliphatic carbon-carbon bond. In examples such as Scheme 4 where one polyamide monomer contains at least one unsaturated aliphatic carbon-carbon bond and the other does not, the relative ratio of the two monomers can be used to control the amount of unsaturated aliphatic carbon-carbon bonds in the resulting polyamide.

Chem.

[0051] Scheme 5 shows the polycondensation reaction between an amino acid polyamide monomer and a polyamine amide monomer, where C-1 and C-2 represent the portions of each polyamide monomer between the carboxylic acid and amine moiety or two amine moieties involved in the polycondensation reaction. With respect to the compositions and methods of the present disclosure, C-1, C-2, or both C-1 and C-2 may contain at least one unsaturated aliphatic carbon-carbon bond.

Chem.

[0052] In the formula, C-1 of Scheme 5 contains at least one unsaturated aliphatic carbon-carbon bond, and most of the resulting polyamide contains unsaturated aliphatic carbon-carbon bonds. In the formula, C-2 of Scheme 5 contains at least one unsaturated aliphatic carbon-carbon bond, and C-1 of Scheme 5 does not contain an unsaturated aliphatic carbon-carbon bond. Only the unsaturated aliphatic carbon-carbon bond of C-2 in the single case per polymer chain may participate in future crosslinking (e.g., during densification of an additive manufacturing method). In such an example, the resulting polyamide has a lower crosslinking potential than some of the other examples herein. Scheme 6 is a non-limiting example of Scheme 5, in which C-2 contains at least one unsaturated aliphatic carbon-carbon bond and C-1 does not contain an unsaturated aliphatic carbon-carbon bond.

Chemical Structure

[0053] Scheme 7 shows a polycondensation reaction between an amino acid polyamide monomer and a polyacid polyamide monomer, in which C-1 and C-2 represent the parts of the respective polyamide monomers between the carboxylic acid and amine moieties or two carboxylic acid moieties participating in the polycondensation reaction. With respect to the compositions and methods of the present disclosure, C-1, C-2, or both C-1 and C-2 may contain at least one unsaturated aliphatic carbon-carbon bond.

Chemical Structure

[0054] In the formula, C-1 of Scheme 7 contains at least one unsaturated aliphatic carbon-carbon bond, and most of the resulting polyamide contains unsaturated aliphatic carbon-carbon bonds. In the formula, C-2 of Scheme 7 contains at least one unsaturated aliphatic carbon-carbon bond, and C-1 of Scheme 7 does not contain an unsaturated aliphatic carbon-carbon bond. Only the unsaturated aliphatic carbon-carbon bond of C-2 in the single case per polymer chain may participate in future crosslinking (for example, during densification by an additive manufacturing method). In such an example, the resulting polyamide has a lower crosslinking potential than some of the other examples herein. Scheme 8 is a non-limiting example of Scheme 7, in which C-2 contains at least one unsaturated aliphatic carbon-carbon bond and C-1 does not contain an unsaturated aliphatic carbon-carbon bond.

Chemical formula

[0055] Scheme 9 shows a polycondensation reaction between an amino acid polyamide monomer, a polyamine polyamide monomer, and a polyacid polyamide monomer. In the formula, C-1, C-2, and C-3 represent the portions of the respective polyamide monomers between the carboxylic acid participating in the polycondensation reaction, the amine moiety (C-1), the two amine moieties (C-2), and the two carboxylic acid moieties (C-3). With respect to the compositions and methods of the present disclosure, one or more of C-1, C-2, and C-3 may contain at least one unsaturated aliphatic carbon-carbon bond.

Chemical formula

[0056] Scheme 10 shows a polycondensation reaction between a polyamine polyamide monomer and a polyacid polyamide monomer. In the formula, C-1 and C-2 represent the portions of the respective polyamide monomers between the two amine moieties or the two carboxylic acid moieties participating in the polycondensation reaction. With respect to the compositions and methods of the present disclosure, C-1, C-2, or both C-1 and C-2 may contain at least one unsaturated aliphatic carbon-carbon bond.

Chemical formula

[0057] The polycondensation reaction examples of Schemes 1 to 10 are non-limiting examples. Additional polyamide monomers may be included in such schemes. For example, Scheme 10 may include a third polyamide monomer that is a polyacid polyamide monomer having a C-3 moiety between two amine moieties. Further, Schemes 1 to 10 represent a diacid polyamide monomer, a diamine polyamide monomer, and an amino acid polyamide monomer having one amine moiety and one carboxylic acid moiety. Those skilled in the art will recognize how the said schemes extend to polyacid polyamide monomers, polyamine polyamide monomers, and amino acid polyamide monomers having one or more amine moieties and one or more carboxylic acid moieties.

[0058] Scheme 11 shows a ring-opening reaction between a cyclic polyamide monomer and an amino acid polyamide monomer, wherein C-1 represents the portion of the amino acid polyamide monomer between the amine and carboxylic acid moieties involved in the reaction. With respect to the compositions and methods of the present disclosure, C-1 includes at least one unsaturated aliphatic carbon-carbon bond.

Chemical formula

[0059] Scheme 12 shows a ring-opening reaction between a cyclic polyamide monomer and a polyacid polyamide monomer, wherein C-1 represents the portion of the polyacid polyamide monomer between the two carboxylic acid moieties involved in the reaction. With respect to the compositions and methods of the present disclosure, C-1 includes at least one unsaturated aliphatic carbon-carbon bond.

Chemical formula

[0060] Scheme 13 shows a ring-opening reaction between a cyclic polyamide monomer and a polyamine polyamide monomer, where C-1 represents the portion of the polyamine polyamide monomer between the two amine moieties involved in the reaction. With respect to the compositions and methods of the present disclosure, C-1 contains at least one unsaturated aliphatic carbon-carbon bond.

Chemical formula

[0061] The examples of the ring-opening reactions of Schemes 11 to 13 are non-limiting examples. Additional polyamide monomers may be included in such schemes. For example, Scheme 13 may include a third polyamide monomer that is a polyacid polyamide monomer having a C-2 portion between two carboxylic acid moieties. Further, Schemes 11 to 13 show a diacid polyamide monomer, a diamine polyamide monomer, and an amino acid polyamide monomer having one amine moiety and one carboxylic acid moiety. Those skilled in the art will recognize how such schemes extend to polyacid polyamide monomers, polyamine polyamide monomers, and amino acid polyamide monomers having one or more amine moieties and one or more carboxylic acid moieties.

[0062] Examples of amino acid polyamide monomers having no at least one unsaturated aliphatic carbon-carbon bond and suitable for use in polycondensation include, but are not limited to, HN-(CH2) where n is 1 to 20 n -COOH, branched aliphatic amino acids (e.g., C4 to C 20 ), cyclic aliphatic amino acids (e.g., C4 to C 20 ), aromatic amino acids (e.g., 3-aminobenzoic acid, 4-aminobenzoic acid), etc., and any combination thereof.

[0063] Examples of amino acid polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, maleamic acid, N-propylmaleamic acid, etc., and any combination thereof.

[0064] Examples of polyacid polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond and being suitable for use in polycondensation include, but are not limited to, HOOC-(CH2) where n is from 1 to 20 n -COOH (e.g., adipic acid, terephthalic acid, isophthalic acid, pimelic acid, suberic acid, decanedioic acid, dodecanedioic acid), isophthalic acid, terephthalic acid, pent-2-enedioic acid, dodec-2-enedioic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, etc., and any combination thereof.

[0065] Examples of polyacid polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, fumaric acid, maleic acid, glutaconic acid, aconitic acid, itaconic acid, etc., and any combination thereof.

[0066] Examples of polyamine polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond and being suitable for use in polycondensation include, but are not limited to, HN-(CH2) where n is from 1 to 20 n-NH, 1,5-diamino-2-methylpentane, 1,2-diaminopropane, trimethylhexamethylenediamine, 2-methyloctane-1,8-diamine, n-methyl 1,6-hexamethylenediamine where N is 2 or 3, n-methyl 1,7-heptamethylenediamine where N is 2-4, n-methyl 1,8-octamethylenediamine where N is 2-4, n-methyl 1,12-dodecamethylenediamine where N is 2-6, 1,3-bis(aminomethyl)benzene, ortho-phenylene-bis(methylamine), 1,4-bis(aminomethyl)benzene, 1,4-cyclohexanediamine, 4-methylcyclohexane-1,3-diamine, 4-methylcyclohexane-1,3-diamine, diphenylethylenediamine, diphenylethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 4,4'-methylenebis(cyclohexylamine), 4,4'-biphenyldiamine, 1,8-diaminonaphthalene, etc., and any combination thereof.

[0067] Examples of polyamine polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, 1,4-diamino-2-butene, 1,5-bis(3-aminophenyl)-1,4-pentadien-3-one (DADBA), trans-4-cyclohexene-1,2-diamine, etc., and any combination thereof.

[0068] Examples of cyclic polyamide monomers suitable for use in ring-opening polymerization include, but are not limited to, azetidinone, 2-azetidinone, 2-pyrrolidinone, 2-piperidinone, ε-caprolactam, 2-azacyclooctanone, 2-azacyclononanone, 2-azacyclodecanone, 2-azacycloundecanone, 2-aza-cyclododecanone, laurolactam, butyrolactam, pivalolactam, ε-caprolactam, caprylolactam, enanthlactam, undecanonelactam, laurolactam (dodecanolactam), etc., and any combination thereof.

[0069] The polycondensation reaction (e.g., Schemes 1-10 and variations thereof) can be carried out in the presence of an activator and / or a metal salt. Examples of activators include, but are not limited to, triphenylphosphine, etc., and any combination thereof. Examples of metal salts include, but are not limited to, calcium chloride, cesium fluoride, etc., and any combination thereof.

[0070] The polycondensation reaction (e.g., Schemes 1-10 and variations thereof) can be carried out at about 50°C to about 200°C (or about 50°C to about 100°C, or about 75°C to about 150°C, or about 125°C to about 200°C).

[0071] The polycondensation reaction (e.g., Schemes 1-10 and variations thereof) can be carried out over about 5 minutes to about 24 hours (or about 5 minutes to about 6 hours, or about 2 hours to about 12 hours, or about 6 hours to about 24 hours).

[0072] The polycondensation reaction (e.g., Schemes 1-10 and variations thereof) can be carried out in a solvent including, but not limited to, N-methylpyrrolidone (NMP), pyridine, dichloromethane, dimethyl sulfoxide (DMSO), N,N-dimethylformamide, acetonitrile, tetrahydrofuran, etc., and any combination thereof.

[0073] The polycondensation reaction (e.g., Schemes 1 to 10 and variations thereof) can be carried out with a molar ratio of a polyamide monomer having (cumulatively) at least one unsaturated aliphatic carbon-carbon bond to a polyamide monomer having (cumulatively) no unsaturated aliphatic carbon-carbon bond of from about 500:1 to about 1:500 (or from about 500:1 to about 100:1, or from about 250:1 to about 50:1, or from about 100:1 to about 10:1, or from about 50:1 to about 1:1, or from about 25:1 to about 1:25, or from about 1:1 to about 1:50, or from about 1:10 to about 1:100, or from about 1:50 to about 1:250, or from about 1:100 to about 1:500). The greater the amount of the polyamide monomer having at least one unsaturated aliphatic carbon-carbon bond included in the polycondensation reaction, the greater the number of sites where crosslinking can occur (e.g., during consolidation of an additive manufacturing method).

[0074] The ring-opening polymerization reaction (e.g., Schemes 11 to 13 and variations thereof) can be carried out in the presence of an activator and / or a metal salt. Examples of the activator include, but are not limited to, triphenylphosphine, etc., and any combination thereof. Examples of the metal salt include calcium chloride, cesium fluoride, etc., and any combination thereof.

[0075] The ring-opening polymerization reaction (e.g., Schemes 11 to 13 and variations thereof) can be carried out at from about 50°C to about 200°C (or from about 50°C to about 100°C, or from about 75°C to about 150°C, or from about 125°C to about 200°C).

[0076] The ring-opening polymerization reaction (e.g., Schemes 11 to 13 and variations thereof) can be carried out over from about 5 minutes to about 24 hours (or from about 5 minutes to about 6 hours, or from about 2 hours to about 12 hours, or from about 6 hours to about 24 hours).

[0077] The ring-opening polymerization reaction (e.g., Schemes 11 to 13 and variations thereof) can be carried out in a solvent including, but not limited to, N-methylpyrrolidone (NMP), pyridine, dichloromethane, dimethyl sulfoxide (DMSO), N,N-dimethylformamide, acetonitrile, tetrahydrofuran, etc., and any combination thereof.

[0078] The ring-opening polymerization reaction (e.g., Schemes 11-13 and variations thereof) can be carried out at a molar ratio of a polyamide monomer having (cumulatively) at least one unsaturated aliphatic carbon-carbon bond to a polyamide monomer having (cumulatively) no unsaturated aliphatic carbon-carbon bond of about 500:1 to about 1:500 (or about 500:1 to about 100:1, or about 250:1 to about 50:1, or about 100:1 to about 10:1, or about 50:1 to about 1:1, or about 25:1 to about 1:25, or about 1:1 to about 1:50, or about 1:10 to about 1:100, or about 1:50 to about 1:250, or about 1:100 to about 1:500). The greater the amount of the polyamide monomer having at least one unsaturated aliphatic carbon-carbon bond included in the polycondensation reaction, the greater the number of potential cross-linking sites.

[0079] Unsaturated polyamides obtained from any suitable synthetic route can have a molar equivalent of a polyamide unit having at least one unsaturated aliphatic carbon-carbon bond to a polyamide unit having no unsaturated aliphatic carbon-carbon bond of about 500:1 to about 1:500 (or about 500:1 to about 100:1, or about 250:1 to about 50:1, or about 100:1 to about 10:1, or about 50:1 to about 1:1, or about 25:1 to about 1:25, or about 1:1 to about 1:50, or about 1:10 to about 1:100, or about 1:50 to about 1:250, or about 1:100 to about 1:500). Initiator-doped, unsaturated polyamide compositions and methods

[0080] The methods and compositions described herein include unsaturated polyamides doped with initiators suitable for cross-linking the unsaturated polyamides (e.g., during consolidation of an additive manufacturing process). The initiator may be a thermal initiator, a photoinitiator, or a combination of a thermal initiator and a photoinitiator.

[0081] Examples of thermal initiators include ammonium persulfate, sodium persulfate, potassium persulfate, organic peroxides (e.g., benzoyl peroxide, t-amyl peracetate, 2,5-dimethyl-2,5-bis(t-butylperoxy)-3-hexyne, 2,5-dimethyl-2,5-di-(t-butylperoxy)-hexane, t-butyl alpha-cumyl peroxide, dibutyl peroxide, t-butyl hydroperoxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoic acid)-3-hexyne, 1,3-bis(t-butylperoxyisopropyl)benzene, lauroyl peroxide, di-t-amyl peroxide, 1,1-di-(t-butylperoxy)cyclohexane, 2,2-di-(t-butylperoxy)butane, and 2,2-di-(t-amylperoxy)propane), 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(isobutyronitrile) (azobis(isobutyronitrile), AIBN), 1,1'-azobis(cyclohexanecarbonitrile), 1,1'-azobis(cyanocyclohexane), 2,2'-azodi(2-methylbutyronitrile), 2-methyl-2-2'-azobispropanenitrile, 2-2'-azobisisobutylamide dehydrate, 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, 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-tetrahydropyrimidin-2-yl)propane] dihydrochloride, 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, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate, etc., and any combination thereof, but not limited thereto.,

[0082] Examples of photoinitiators include, but are not limited to, (±)-camphorquinone, acetophenone, 3-acetophenol, 4-acetophenol, benzophenone, 2-methylbenzyl phenyl ketone, 3-methylbenzophenone, 3-hydroxybenzophenone, 3,4-dimethylbenzophenone, 4-hydroxybenzophenone, 4-benzoylbenzoic acid, 2-benzoylbenzoic acid, methyl-2-benzoylbenzoate, 4,4'-dihydroxybenzophenone, 4-(dimethylamino)-benzophenone, 4,4'-bis(dimethylamino)-benzophenone, 4,4'-bis(diethylamino)-benzophenone, 4,4'-dichlorobenzophenone, 4-(p-tolylthio)benzophenone, 4-phenylbenzophenone, 1,4-dibenzoylbenzene, benzyl, 4,4'-dimethylbenzyl, p-anisyl, 2-benzoyl-2-propanol, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 1-benzoylcyclohexanol, benzoin, anisoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, O-tosylbenzoin, 2,2-diethoxyacetophenone, benzyl dimethyl ketal, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, 2-isonitroso-propiophenone, anthraquinone, 2-ethylanthraquinone, sodium anthraquinone-2-sulfonate hydrate, 9,10-phenanthrenequinone, 9,10-phenanthrenequinone, dibenzosuberone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthen-9-one, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,((Trimethylbenzoyl)phosphine oxide, TPO), acyl phosphine oxide (APO), bis acyl phosphine oxide (BAPO), lithium phenyl(2,4,6 - trimethylbenzoyl)phosphinate, etc., and any combination thereof may be mentioned.,

[0083] Several methods can be used to dope the unsaturated polyamide with an initiator. Generally, the doping can occur by melt blending, dry blending (as defined above), wet blending (as defined above), or a combination thereof.

[0084] In melt blending, one or more unsaturated polyamides are melted and mixed with one or more initiators. In such blends, other additives (e.g., other thermoplastic polymers, fillers, etc.) may optionally be included. However, the melt temperature should be below the temperature at which one or more initiators cause crosslinking. Generally, the melt blending method is limited because the initiators available for use at the temperature required to melt the unsaturated polyamide are limited.

[0085] In dry blending, one or more unsaturated polyamides may be mixed with one or more initiators. In such blends, other additives (e.g., other thermoplastic polymers, fillers, etc.) may optionally be included. In dry blending, each of the components to be blended should have less than 10% by weight of a solvent and / or dispersant (e.g., water, methanol, acetone, etc., and any combination thereof) present in the weight of the component. Dry blending can be carried out with a blender or other mixer that produces a shearing force that breaks up the fine particles of the unsaturated polyamide and / or the initiator. In some cases, the initiator may be liquid at room temperature. In such cases, the initiator may be coated and / or absorbed onto the unsaturated polyamide particles.

[0086] In wet blending, one or more unsaturated polyamides may be mixed with one or more initiators in the presence of a solvent and / or a dispersant (e.g., water, methanol, acetone, etc., and any combination thereof). In such blends, other additives (e.g., other thermoplastic polymers, fillers, etc.) may optionally be included. In the methods described herein, generally, one or more unsaturated polyamides may typically be dispersed as solid particles in a fluid, and one or more initiators (either dry or wet) may be added to the dispersion and / or added during the addition of the fluid unsaturated polyamide. Again, other additives may be included in the dispersion. The dispersion may be mixed for a desired time (e.g., about 15 minutes to about 1 day, or about 30 minutes to about 3 hours), then filtered, washed, and dried to remove the fluid (preferably dried such that less than 10 wt% of the fluid remains). Optionally, during mixing, the initiator may be absorbed by the unsaturated polyamide particles.

[0087] In each blending method, the aim is to produce a mixture of one or more unsaturated polyamides and one or more initiators.

[0088] The weight ratio of unsaturated polyamide(s) (cumulatively) to initiator(s) (cumulatively) may be from about 90:10 to about 99:1. Initiator doping, selective laser sintering using unsaturated polyamides

[0089] As described herein, SLS uses polymer particles (or powders) to produce an object. The methods and compositions of the present disclosure include particles comprising the unsaturated polyamides and initiators described herein.

[0090] The particles may be produced by a precipitation method, a cryogenic milling method, or a melt emulsification method. Depending on these methods, the initiator may be present during and / or after the formation of the particles.

[0091] An exemplary precipitation method for generating particles is direct emulsion polymerization in which the polycondensation and / or ring-opening reaction described herein is carried out during emulsification. The discontinuous phase of the emulsion is where the polycondensation reaction occurs. Then, when the reaction stops, the discontinuous phase becomes unsaturated polyamide particles. In this example, the doping of the initiator is preferably carried out after the formation of the unsaturated polyamide particles. If the initiator is present during the polycondensation reaction, crosslinking may occur. Thus, the initiator-doped unsaturated polyamide particles are preferably formed first by direct emulsion polymerization and precipitation to form unsaturated polyamide particles, and then the resulting particles are formed by wet and / or dry blending with the initiator. As a non-limiting example, the method of the present disclosure is to carry out emulsion polymerization via a polycondensation and / or ring-opening reaction between a first polyamide monomer and a second polyamide monomer (e.g., via one or more of Schemes 1 to 13), wherein the second polyamide monomer contains at least one unsaturated aliphatic carbon-carbon bond for generating an unsaturated polyamide, emulsion polymerization, precipitating the unsaturated polyamide as particles, and blending the particles containing the unsaturated polyamide with the initiator (via wet and / or dry blending).

[0092] In another example of particle generation, the unsaturated polyamide can be dissolved in a solvent (e.g., ethanol or propanol) under high pressure and high temperature (e.g., about 100 °C to about 150 °C). Upon cooling, the unsaturated polyamide precipitates into particles. In the present specification, this method is referred to as heat-induced precipitation. In this example, the initiator can be present with the unsaturated polyamide after precipitation. Alternatively, or in addition to such embodiments, the precipitated particles may be wet and / or dry blended with the initiator. As a non-limiting example, the method of the present disclosure can include dissolving an unsaturated polyamide (e.g., one or more products of Schemes 1-13) in a solvent, precipitating the unsaturated polyamide as particles, and blending the particles containing the unsaturated polyamide with the initiator (via wet and / or dry blending). In another non-limiting example, the method of the present disclosure can include dissolving an unsaturated polyamide (e.g., one or more products of Schemes 1-13) and an initiator in a solvent, and precipitating the unsaturated polyamide to obtain particles containing the unsaturated polyamide and the initiator.

[0093] In yet another example, the unsaturated polyamide can be cryogenically cooled and milled to produce particles. In this example, the initiator can be present with the unsaturated polyamide prior to cryogenic milling. Alternatively, or in addition to such embodiments, the resulting particles may be wet and / or dry blended with the initiator. As a non-limiting example, the method of the present disclosure can include cryogenically cooling an unsaturated polyamide (e.g., one or more products of Schemes 1-13), milling the cryogenically cooled unsaturated polyamide to obtain particles, and blending the particles containing the unsaturated polyamide with the initiator (via wet and / or dry blending). In another non-limiting example, the method of the present disclosure can include cryogenically cooling an unsaturated polyamide (e.g., one or more products of Schemes 1-13) in the presence of an initiator, and milling the cryogenically cooled unsaturated polyamide to obtain particles containing the unsaturated polyamide and the initiator.

[0094] In another example, the unsaturated polyamide can be formed into particles by melt emulsification (described in more detail herein). In this example, the initiator may be present in the melt. However, as discussed herein, it is preferred that the temperature of the melt is lower than the temperature at which the initiator crosslinks the unsaturated polyamide. Alternatively, or in addition to such embodiments, the resulting particles may be wet and / or dry blended with the initiator. As a non-limiting example, the method of the present disclosure can include melt emulsifying an unsaturated polyamide (e.g., a product of one or more of Schemes 1-13), cooling the melt emulsion to obtain particles, and blending the particles containing the unsaturated polyamide with the initiator (via wet and / or dry blending). In another non-limiting example, the method of the present disclosure can include melt emulsifying an unsaturated polyamide (e.g., a product of one or more of Schemes 1-13) in the presence of an initiator and cooling the melt emulsion to obtain particles containing the unsaturated polyamide and the initiator.

[0095] In the case of thermally induced precipitation, cryomilling, and melt emulsification, the resulting particles contain an unsaturated polyamide, optionally a thermoplastic polymer different from the unsaturated polyamide, and optionally a compatibilizer. That is, the starting materials for such methods can include an unsaturated polyamide, optionally a thermoplastic polymer different from the unsaturated polyamide, and optionally a compatibilizer. For example, the thermoplastic polymer and optionally the compatibilizer may be dissolved in a solvent prior to precipitation by the thermally induced precipitation method. In another example, the unsaturated polyamide can be melt blended with a thermoplastic polymer different from the unsaturated polyamide and optionally a compatibilizer. The resulting blend polymer can be used in the cryomilling method. In yet another example, the components of the melt emulsion can include an unsaturated polyamide, a thermoplastic polymer different from the unsaturated polyamide, and optionally a compatibilizer.

[0096] The thermoplastic polymer can also have unsaturated sites that participate in crosslinking. The thermoplastic polymer may not participate in crosslinking but can provide other mechanical, thermal, or physical properties. Combinations of the two aforementioned types of thermoplastic polymers can be included.

[0097] The weight ratio of the unsaturated polyamide (cumulatively) to a thermoplastic polymer different from the unsaturated polyamide may be from about 500:1 to about 1:10 (or from about 500:1 to about 100:1, or from about 250:1 to about 50:1, or from about 100:1 to about 10:1, or from about 50:1 to about 1:1, or from about 25:1 to about 1:10). If a large amount of a thermoplastic polymer different from the unsaturated polyamide is included, the crosslinking amount of the obtained object formed by the SLS method is reduced on the condition that the thermoplastic polymer is not involved in crosslinking.

[0098] Examples of thermoplastic polymers include saturated polyamides, polyurethanes, polyethylene, polypropylene, polyacetals, polycarbonates, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polyhexamethylene terephthalate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polyesters (e.g., polylactic acid), polyethers, polyethersulfones, polyetheretherketones, polyacrylates, polymethacrylates, polyimides, acrylonitrile butadiene styrene (ABS), polyphenylene sulfides, vinyl polymers, polyarylene ethers, polyarylene sulfides, polysulfones, polyether ketones, polyamideimides, polyetherimides, polyether esters, copolymers containing polyether blocks and polyamide blocks (PEBA or polyether block amides), grafted or ungrafted thermoplastic polyolefins, functionalized or non-functionalized ethylene / vinyl monomer polymers, functionalized or non-functionalized ethylene / alkyl (meth)acrylate, functionalized or non-functionalized (meth)acrylic acid polymers, functionalized or non-functionalized 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 (polyvinylidenefluoride, PVDF), phenolic resin, poly(ethylene / vinyl acetate), polybutadiene, polyisoprene, styrene block copolymer, polyacrylonitrile, silicone, etc., and any combination thereof, but not limited thereto. Also, copolymers containing one or more of the foregoing may be used in the methods and systems of the present disclosure.

[0099] Other thermoplastic polymers in the compositions and methods of the present disclosure may be elastomeric or non-elastomeric. Some of the foregoing examples of other thermoplastic polymers may be elastomeric or non-elastomeric depending on the exact composition of the polymer. For example, polyethylene, which is a copolymer of ethylene and propylene, may be elastomeric or non-elastomeric depending on the amount of propylene in the polymer.

[0100] Thermoplastic elastomers generally fall within one of six classes: styrenic block copolymers, thermoplastic polyolefin elastomers, thermoplastic vulcanizates (also called elastomer alloys), thermoplastic polyurethanes, thermoplastic copolyesters, and thermoplastic polyamides (typically block copolymers containing polyamide). Examples of thermoplastic polymers can be found in "Handbook of Thermoplastic Elastomers", 2nd Edition, B.M. Walker and C.P. Rader, eds., Van Nostrand Reinhold, New York, 1988. Examples of thermoplastic elastomers include 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, styrenic block copolymers, and polyacrylonitrile, silicone, etc. Examples of elastic styrenic block copolymers can include at least one block selected from the group consisting of isoprene, isobutylene, butylene, ethylene / butylene, ethylene-propylene, and ethylene-ethylene / propylene. More specific examples of elastic 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), etc., and any combination thereof.

[0101] Examples of polyamides include, but are not limited to, polycaproamide, poly(hexamethylene succinamide), polyhexamethylene adipamide, polypentamethylene adipamide, polyhexamethylene sebacamide, polyundecamide, polydodecamide, polyhexamethylene terephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamides, aromatic polyamides, any copolymers thereof, and any combinations thereof. Copolymers may also be used. Examples of 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, and PA10.10 / 10.36, and any combinations thereof. Examples of polyamide elastomers include, but are not limited to, polyester amides, polyether ester amides, polycarbonate-ester amides, and polyether-block-amide elastomers.

[0102] Examples of polyurethanes include, but are not limited to, polyether polyurethanes, polyester polyurethanes, mixed polyether and polyester polyurethanes, and any combinations thereof. Examples of thermoplastic polyurethanes include, but are not limited to, poly[4,4'-methylenebis(phenyl isocyanate)-alt-1,4-butanediol / di(propylene glycol) / polycaprolactone], ELASTOLLAN® 1190A (a polyether polyurethane elastomer available from BASF), ELASTOLLAN® 1190A10 (a polyether polyurethane elastomer available from BASF), and any combinations thereof.

[0103] The compatibilizer can be optionally used to improve the blending efficiency and effect of an unsaturated polyamide and one or more thermoplastic polymers. Examples of polymer compatibilizers include, but are not limited to, PROPOLDER™ MPP2020 20 (polypropylene, available from Polygroup Inc.), PROPOLDER™ MPP2040 40 (polypropylene, available from Polygroup Inc.), NOVACOM™ HFS2100 (maleic anhydride functionalized high density polyethylene polymer, available from Polygroup Inc.), KEN-REACT™ CAPS™ L™ 12 / L (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT™ CAPOW™ L™ 12 / H (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT™ LICA™ 12 (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT™ CAPS™ KPR™ 12 / LV (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT™ CAPOW™ KPR™ 12 / H (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT™ titanates & zirconates (organometallic coupling agent, KenrichAvailable from Petrochemicals), VISTAMAXX (trademark) (ethylene-propylene copolymer, available from ExxonMobil), SANTOPRENE (trademark) (thermoplastic vulcanizate of ethylene-propylene-diene rubber and polypropylene, available from ExxonMobil), VISTALON (trademark) (ethylene-propylene-diene rubber, available from ExxonMobil), EXACT (trademark) (plastomer, available from ExxonMobil) EXXELOR (trademark) (polymer resin, available from ExxonMobil), FUSABOND (trademark) M603 (random ethylene copolymer, available from Dow), FUSABOND (trademark) E226 (anhydride-modified polyethylene, available from Dow), BYNEL (trademark) 41E710 (coextrudable adhesive resin, available from Dow), SURLYN (trademark) 1650 (ionomer resin, available from Dow), FUSABOND (trademark) P353 (chemically modified polypropylene copolymer, available from Dow), ELVALOY (trademark) PTW (ethylene terpolymer, available from Dow), ELVALOY (trademark) 3427AC (copolymer of ethylene and butyl acrylate, available from Dow), LOTADER (trademark) AX8840 (ethylene acrylate-based terpolymer, available from Arkema), LOTADER (trademark) 3210 (ethylene acrylate-based terpolymer, available from Arkema), LOTADER (trademark) 3410 (ethylene acrylate-based terpolymer, available from Arkema), LOTADER (trademark) 3430 (ethylene acrylate-based terpolymer, available from Arkema), LOTADER (trademark) 4700 (ethylene acrylate-based terpolymer, available from Arkema), LOTADER (trademark) AX8900 (ethylene acrylate-based terpolymer, available from Arkema), LOTADER (trademark) 4720 (ethylene acrylate-based terpolymer, available from Arkema), BAXXODUR (trademark) EC 301 (amine for epoxy, available from BASF), BAXXODUR (trademark) EC 311 (amine for epoxy, available from BASF), BAXXODUR (trademark) EC303 (amine for epoxy, available from BASF), BAXXODUR™ EC 280 (amine for epoxy, available from BASF), BAXXODUR™ EC 201 (amine for epoxy, available from BASF), BAXXODUR™ EC 130 (amine for epoxy, available from BASF), BAXXODUR™ EC 110 (amine for epoxy, available from BASF), styrene resin, polypropylene, polyamide, polycarbonate, EASTMAN™ G-3003 (maleic anhydride grafted polypropylene, available from Eastman), RETAIN™ (polymer modifier available from Dow), AMPLIFY TY™ (maleic anhydride grafted polymer, available from Dow), INTUNE™ (olefin block copolymer, available from Dow), etc., and any combination thereof.

[0104] As described herein, in the SLS process, heat from a laser and other sources is used to consolidate the particles (e.g., the chamber may be heated below the melting temperature of the polymer in the particles). To enhance the heating caused by the laser, the particles used in the SLS process may contain an infrared absorber and / or may be mixed with an infrared absorber. Generally, an infrared absorber absorbs electromagnetic radiation (e.g., at one or more wavelengths from about 100 nm to about 1 mm) and generates heat. The infrared absorber can accelerate the initiation of an initiator, and as a result, cross-link (e.g., during consolidation of an additive manufacturing process). Examples of infrared absorbers include, but are not limited to, carbon black, charcoal, carbon fiber, carbon nanotubes, graphite, copper hydroxide phosphate, chalk, bone, interference pigments (e.g., IRIODIN® available from Merck), nacreous pigments, metal oxide-coated mica pigments, etc. colorants and / or pigments (e.g., organic or inorganic, and synthetic or natural), oxides and sulfides such as antimony oxide, tin oxide, indium oxide, zinc oxide, zinc sulfide, tin sulfide, or mixtures thereof, agents based on melamine cyanurate (MELAPUR® available from DSM), or flame retardant agents such as agents based on phosphorus, preferably phosphate, phosphite, phosphonite, or elemental red phosphorus, carbon fiber, glass beads (hollow, porous, or solid kaolin, wollastonite, etc., and any combination thereof). The infrared absorber may be dispersed as is or may be dispersed on a substrate such as mica to be subsequently dispersed. The infrared absorber may be present in the particles and incorporated with the particles as described for the initiator.

[0105] The particles used in the SLS process described herein may comprise (a) initiator-doped unsaturated polyamide particles comprising an unsaturated polyamide, an initiator, optionally an infrared absorber, optionally a thermoplastic polymer different from the unsaturated polyamide, optionally a compatibilizer, and optionally other additives, and optionally (b) other thermoplastic particles comprising a thermoplastic polymer different from the unsaturated polyamide and optionally a compatibilizer.

[0106] The SLS method can include depositing initiator-doped unsaturated polyamide particles (and optionally other thermoplastic particles) on a surface, and after deposition, heating at least a portion of the particles to promote consolidation of the particles and crosslinking of the unsaturated polyamide to form a consolidated body (object). Without being bound by theory, heating and / or exposure of the particles to a laser is thought to initiate crosslinking of the unsaturated bonds in the unsaturated polyamide by the initiator.

[0107] Examples of objects that can be produced by the SLS method using the unsaturated polyamides described herein include, but are not limited to, particles, films, packages, toys, household goods, automotive parts, aerospace / aeronautical related parts, containers (e.g., containers for food, beverages, cosmetics, personal care compositions, pharmaceuticals, etc.), shoe soles, furniture parts, decorative household goods, plastic gears, screws, nuts, bolts, cable ties, jewelry, artworks, sculptures, medical items, prostheses, orthopedic implants, products of artifacts that assist learning in education, 3D anatomical models for assisting surgery, robotic engineering supplies, biomedical devices (appliances), household appliances, dental supplies, electronic devices, sports supplies, etc., and can be all or a part of such articles. Further, the particles may be useful in applications including, but not limited to, paints, powder coatings, inkjet materials, electrophotographic toners, 3D printing, etc. Melt Emulsification Method and Resulting Particles

[0108] The figure is a flow diagram of a non-limiting, exemplary method 100 of the present disclosure. A thermoplastic polymer 102 (including one or more unsaturated polyamides described herein and optionally one or more other thermoplastic polymers described herein), a dispersion medium 104, and optionally an emulsifying stabilizer 106 are combined at 108 to produce a mixture 110. The components 102, 104, and 106 can be added in any order and can include mixing and / or heating during the process 108 of combining the components 102, 104, and 106.

[0109] Optionally, other additives such as initiators, infrared absorbers, and compatibilizers described herein are included in the mixture and can be combined with components 102, 104, and 106 in any order.

[0110] The mixture 110 is then processed (112) by applying a sufficiently high shear force to the mixture 110 at a temperature above the melting point or softening temperature of the thermoplastic polymer 102, forming a molten emulsion 114. Since the temperature is above the melting point or softening temperature of the thermoplastic polymer 102, the thermoplastic polymer 102 becomes a polymer melt. The shear rate should be sufficient to disperse the polymer melt in the dispersion medium 104 as droplets (i.e., the polymer emulsion 114). Without being bound by theory, it is believed that if all other factors are the same, increasing the shear force should decrease the size of the droplets of the polymer melt in the dispersion medium 104. However, at some point, there may be a diminishing return in reducing the droplet diameter by increasing the shear force, or there may be a splitting into the droplet contents that degrades the quality of the particles produced.

[0111] Next, the molten emulsion 114 inside and / or outside the mixing vessel is cooled (116), and the polymer droplets are solidified into thermoplastic polymer particles (also referred to as solidified thermoplastic polymer particles). Next, the cooled mixture 118 is processed (120), and the thermoplastic polymer particles 122 are isolated from other components 124 (e.g., dispersion medium 104, excess emulsifying stabilizer 106, etc.), and the thermoplastic polymer particles 122 can be washed or otherwise purified. The thermoplastic polymer particles 122 contain the thermoplastic polymer 102 and, when included, at least a portion of the emulsifying stabilizer 106 that coats the outer surface of the thermoplastic polymer particles 122. The emulsifying stabilizer 106 or a portion thereof may be deposited as a uniform coating on the thermoplastic polymer particles 122. In some cases, depending on non-limiting factors such as temperature (including cooling rate), the type of thermoplastic polymer 102, and the type and size of the emulsifying stabilizer 106, the nanoparticles of the emulsifying stabilizer 106 can be at least partially embedded within the outer surface of the thermoplastic polymer particles 122 during the process of associating therewith. Even when the embodiment is not carried out, at least the nanoparticles within the emulsifying stabilizer 106 can remain strongly associated with the thermoplastic polymer particles 122, facilitating their further use. In contrast, a dry blend of pre-formed thermoplastic polymer microparticles (e.g., formed by cryogenic milling or precipitation processes) and a flow aid such as silica nanoparticles does not result in a robust and uniform coating of the flow aid on the thermoplastic polymer microparticles.

[0112] Advantageously, the dispersion medium and washing solvent of the systems and methods described herein (e.g., method 100) can be recycled and reused. One of ordinary skill in the art will recognize any necessary washing of the used dispersion medium and solvent required for the recycling process.

[0113] The thermoplastic polymer 102 and the dispersion medium 104 should be selected such that the thermoplastic polymer 102 and the dispersion medium 104 are immiscible at various processing temperatures (e.g., from room temperature to the process temperature). An additional factor that can be considered is the difference (e.g., difference or ratio) in viscosity at the process temperature between the molten polyamide 102 and the dispersion medium 104. The difference in viscosity can affect droplet breakup and particle size distribution. Without being bound by theory, if the viscosities of the molten polyamide 102 and the dispersion medium 104 are too similar, the roundness of the overall product can be reduced, the particles can become more oval-shaped, and a more elongated structure can be observed.

[0114] The thermoplastic polymer 102 can have a melting point or softening temperature of about 50 °C to about 450 °C (or about 50 °C to about 125 °C, or about 100 °C to about 175 °C, or about 150 °C to about 280 °C, or about 200 °C to about 350 °C, or about 300 °C to about 450 °C).

[0115] The thermoplastic polymer 102 may have a glass transition temperature (using a heating and cooling rate of 10 °C / min according to ASTM E1356-08(2014)) of about -50 °C to about 400 °C (or about -50 °C to about 0 °C, or about -25 °C to about 50 °C, or about 0 °C to about 150 °C, or about 100 °C to about 250 °C, or about 150 °C to about 300 °C, or about 200 °C to about 400 °C).

[0116] The thermoplastic polymer 102 may optionally contain additives. Typically, the additives are those that are present before the thermoplastic polymer 102 is added to the mixture 110. Accordingly, in the thermoplastic polymer melt droplets and the resulting thermoplastic polymer particles, the additives are dispersed throughout the thermoplastic polymer. Correspondingly, for clarity, this additive is referred to herein as an "internal additive". The internal additive may be blended with the thermoplastic polymer immediately before preparing the mixture 110 or the well.

[0117] When describing the amounts of the components in the compositions described herein (e.g., mixture 110 and thermoplastic polymer particles 122), the weight percentages are based on the thermoplastic polymer 102 without internal additives. For example, a composition containing 1 wt% of an emulsion stabilizer with respect to the weight of 100 g of thermoplastic polymer 102 containing 10 wt% of internal additives and 90 wt% of thermoplastic polymer is a composition containing 0.9 g of emulsion stabilizer, 90 g of thermoplastic polymer, and 10 g of internal additives.

[0118] The internal additives may be present in the thermoplastic polymer 102 at about 0.1 wt% to about 60 wt% (or about 0.1 wt% to about 5 wt%, or about 1 wt% to about 10 wt%, or about 5 wt% to about 20 wt%, or about 10 wt% to about 30 wt%, or about 25 wt% to about 50 wt%, or about 40 wt% to about 60 wt%) of the thermoplastic polymer 102. For example, the thermoplastic polymer 102 may include about 70 wt% to about 85 wt% of thermoplastic polymer and about 15 wt% to about 30 wt% of internal additives such as glass fibers or carbon fibers.

[0119] Examples of internal additives include, but are not limited to, fillers, reinforcing agents, pigments, pH adjusters, etc., and combinations thereof. Examples of fillers include, but are not limited to, glass fibers, glass particles, mineral fibers, carbon fibers, oxide particles (e.g., titanium dioxide and zirconium dioxide), metal particles (e.g., aluminum powder), etc., and any combination thereof. Examples of pigments include, but are not limited to, organic pigments, inorganic pigments, carbon black, etc., and any combination thereof.

[0120] The thermoplastic polymer 102 may be present in the mixture 110 at about 5 wt% to about 60 wt% (or about 5 wt% to about 25 wt%, or about 10 wt% to about 30 wt%, or about 20 wt% to about 45 wt%, or about 25 wt% to about 50 wt%, or about 40 wt% to about 60 wt%) of the combined thermoplastic polymer 102 and dispersion medium 104.

[0121] A suitable dispersion medium 104 has a viscosity of about 1,000 cSt to about 150,000 cSt (or about 1,000 cSt to about 60,000 cSt, or about 40,000 cSt to about 100,000 cSt, or about 75,000 cSt to about 150,000 cSt) at 25°C.

[0122] Examples of the dispersion medium 104 include, but are not limited to, silicone oil, fluorinated silicone oil, perfluorinated silicone oil, polyethylene glycol, alkyl-terminated polyethylene glycol (e.g., C1-C4 terminal alkyl groups such as tetraethylene glycol dimethyl ether (TDG)), paraffin, liquid petrolatum, mink oil, turtle oil, soybean oil, perhydrosqualene, sweet almond oil, carophyllum oil, palm oil, pearl rim oil, grape seed oil, sesame oil, corn oil, rapeseed oil, sunflower oil, cottonseed oil, apricot oil, castor oil, avocado oil, jojoba oil, olive oil, cereal germ oil, esters of lanolinic acid, esters of oleic acid, esters of lauric acid, esters of stearic acid, aliphatic esters, higher fatty acids, aliphatic alcohols, polysiloxanes modified with fatty acids, polysiloxanes modified with aliphatic alcohols, polysiloxanes modified with polyoxyalkylene, etc., and any combination thereof. Examples of silicone oil include, but are not limited to, polydimethylsiloxane, 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, etc., and any combination thereof. When the dispersion medium 104 contains two or more of the foregoing, the dispersion medium 104 may have one or more phases. For example, a polysiloxane modified with a fatty acid and a polysiloxane modified with an aliphatic alcohol (preferably having a chain length similar to that of the fatty acid and the aliphatic alcohol) may form a single-phase dispersion medium 104. In another example, a dispersion medium 104 containing silicone oil and alkyl-terminated polyethylene glycol may form a two-phase dispersion medium 104.

[0123] The dispersion medium 104 may be present in the mixture 110 at about 40 wt% to about 95 wt% (or about 75 wt% to about 95 wt%, or about 70 wt% to about 90 wt%, or about 55 wt% to about 80 wt%, or about 50 wt% to about 75 wt%, or about 40 wt% to about 60 wt%) of the combined thermoplastic polymer 102 and the dispersion medium 104.

[0124] Optionally, the dispersion medium 104 may have a density of about 0.6 g / cm 3 ~ about 1.5 g / cm 3 and the thermoplastic polymer 102 may have a density of about 0.7 g / cm 3 ~ about 1.7 g / cm 3 and the thermoplastic polymer may have a density similar to, lower than, or higher than the density of the dispersion medium.

[0125] The emulsifying stabilizers used in the methods and compositions of the present disclosure may include nanoparticles (e.g., oxide nanoparticles, carbon black, polymer nanoparticles, and combinations thereof), surfactants, etc., and any combination thereof.

[0126] The oxide nanoparticles may be metal oxide nanoparticles, non-metal oxide nanoparticles, or mixtures thereof. Examples of oxide nanoparticles include, but are not limited to, silica, titania, zirconia, alumina, iron oxide, copper oxide, tin oxide, boron oxide, cerium oxide, thallium oxide, and tungsten oxide, and any combination thereof. Mixed metal oxides and / or non-metal oxides such as aluminosilicates, borosilicates, and aluminoborosilicates are also included within the term metal oxides. The oxide nanoparticles may be hydrophilic or hydrophobic, and may be natural particles or the result of surface treatment of the particles. For example, silica nanoparticles having a hydrophobic surface treatment such as dimethylsilyl, trimethylsilyl, etc. may be used in the methods and compositions of the present disclosure. In addition, silica having a functional surface treatment such as a methacrylate functional group may be used in the methods and compositions of the present disclosure. Non-functionalized oxide nanoparticles may also be suitable for use.

[0127] Examples of commercially available silica nanoparticles include, but are not limited to, AEROSIL® (e.g., AEROSIL® R812S (hydrophobically modified surface and silica nanoparticles with an average diameter of about 7 nm and a BET surface area of 260 ± 30 m 2 / g), AEROSIL® RX50 (hydrophobically modified surface and silica nanoparticles with an average diameter of about 40 nm and a BET surface area of 35 ± 10 m 2 / g), AEROSIL® 380 (hydrophobically modified surface and silica nanoparticles with a surface area of 380 ± 30 m 2 / g)), etc., and any combination thereof.

[0128] Carbon black is another type of nanoparticle that can be present as an emulsifier stabilizer in the compositions and methods disclosed herein. Various grades of carbon black are familiar to those skilled in the art, and any of them can be used herein. Other nanoparticles that can absorb infrared rays may likewise be used.

[0129] Polymer nanoparticles are another type of nanoparticle that can be present as an emulsifier stabilizer in the disclosure herein. Suitable polymer nanoparticles may include one or more polymers that are thermosetting and / or crosslinked so as not to melt when processed by melt emulsification according to the disclosure within this specification. High molecular weight thermoplastic polymers having a high melting point or decomposition point may likewise include suitable polymer nanoparticle emulsifier stabilizers.

[0130] The nanoparticles can have an average diameter (D50 based on volume) of about 1 nm to about 500 nm (or about 10 nm to about 150 nm, or about 25 nm to about 100 nm, or about 100 nm to about 250 nm, or about 250 nm to about 500 nm).

[0131] The nanoparticles are about 10 m 2 / g to about 500 m 2 / g (or about 10 m 2 / g to about 150 m 2 / g, or about 25 m 2 / g to about 100 m 2 / g, or about 100 m 2 / g to about 250 m 2 / g, or 250 m 2 / g to about 500 m 2 / g).

[0132] The nanoparticles can be included in the mixture 110 at a concentration of about 0.01 wt% to about 10 wt% (or about 0.01 wt% to about 1 wt%, or about 0.1 wt% to about 3 wt%, or about 1 wt% to about 5 wt%, or about 5 wt% to about 10 wt%) based on the weight of the thermoplastic polymer 102.

[0133] The surfactant can be anionic, chaotropic, nonionic, or zwitterionic. Examples of surfactants include, but are not limited to, sodium dodecyl sulfate, sorbitan oleate, poly[dimethylsiloxane-co-[[3-(2-(2-hydroxyethoxy)ethoxy)propylmethylsiloxane]], sodium docusate (sodium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate), and the like, and any combination thereof. Commercially available examples of surfactants include, but are not limited to, CALFAX® DB-45 (sodium dodecyldiphenyloxide disulfonate, available from Pilot Chemicals), SPAN® 80 (sorbitan maleate nonionic surfactant), MERPOL® surfactant (available from Stepan Company), TERGITOL™ TMN-6 (water-soluble nonionic surfactant, available from DOW), TRITON® X-100 (octylphenol ethoxylate, available from SigmaAldrich), IGEPAL® CA-520 (polyoxyethylene(5) isooctylphenyl ether, available from SigmaAldrich), BRIJ® S10 (polyethylene glycol octadecyl ether, available from SigmaAldrich), and the like, and any combination thereof.

[0134] The surfactant can be contained in the mixture 110 at a concentration of about 0.01 wt% to about 10 wt% (or about 0.01 wt% to about 1 wt%, or about 0.5 wt% to about 2 wt%, or about 1 wt% to about 3 wt%, or about 2 wt% to about 5 wt%, or about 5 wt% to about 10 wt%) based on the weight of the polyamide 102. Alternatively, the mixture 110 may not contain (or be absent of) the surfactant.

[0135] The weight ratio of the nanoparticles to the surfactant may be about 1:10 to about 10:1 (or about 1:10 to about 1:1, or about 1:5 to about 5:1, or about 1:1 to about 10:1).

[0136] As described above, the components 102, 104, and 106 can be added in any order and may include mixing and / or heating in the process 108 that includes the components 102, 104, and 106. For example, the emulsifying stabilizer 106 may first be dispersed in the dispersion medium 104, optionally with heating of the dispersion, before adding the thermoplastic polymer 102. In another non-limiting example, the thermoplastic polymer 102 can be heated to produce a polymer melt in which the dispersion medium 104 and the emulsifying stabilizer 106 are added together or in any order. In yet another non-limiting example, the thermoplastic polymer 102 and the carrier fluid 104 can be mixed at a temperature above the melting point or softening temperature of the thermoplastic polymer 102 and at a shear rate sufficient to disperse the thermoplastic polymer melt in the carrier fluid 104. The emulsifying stabilizer 106 can then be added to form the mixture 110 and maintained under suitable process conditions for a set period of time.

[0137] Combining components 102, 104, and 106 in any combination (108) can be carried out in a mixing device used for process 112 and / or in another suitable container. As a non-limiting example, the thermoplastic polymer 102 may be heated to a temperature above the melting point or softening temperature of the thermoplastic polymer 102 in the mixing device used for process 112, and the emulsifying stabilizer 106 may be dispersed in the dispersion medium 104 in another container. The dispersion may then be added to the melt of the thermoplastic polymer 102 in the mixing device used for process 112.

[0138] The mixing device used for process 112 to produce the melt emulsion 114 should be able to maintain the melt emulsion 114 at a temperature above the melting point or softening temperature of the thermoplastic polymer 102 and apply a shear rate sufficient to disperse the polymer melt as droplets into the dispersion medium 104.

[0139] Examples of mixing devices used for process 112 to produce the melt emulsion 114 include, but are not limited to, extruders (e.g., continuous extruders, batch extruders, etc.), stirred reactors, blenders, reactors equipped with in-line homogenizer systems, and devices derived therefrom.

[0140] Process 112 and the formation of the melt emulsion 114 under suitable process conditions (e.g., temperature, shear rate, etc.) for a set period of time.

[0141] The temperature of process 112 and the formation of the melt emulsion 114 should be above the melting point or softening temperature of the thermoplastic polymer 102 and below the decomposition temperature of any of the components 102, 104, and 106 in the mixture 110. For example, if the temperature of process 112 and the formation of the melt emulsion 114 is below the decomposition temperature of any of the components 102, 104, and 106 in the mixture 110, the temperature of process 112 and the formation of the melt emulsion 114 may exceed the melting point or softening temperature of the thermoplastic polymer 102 by about 1°C to about 50°C (or about 1°C to about 25°C, or about 5°C to about 30°C, or about 20°C to about 50°C).

[0142] The shear rate for the formation of process 112 and the molten emulsion 114 should be high enough to disperse the polymer melt as droplets into the dispersion medium 104. The droplets should include droplets having a diameter of about 1000 μm or less (or about 1 μm to about 1000 μm, or about 1 μm to about 50 μm, or about 10 μm to about 100 μm, or about 10 μm to about 250 μm, or about 50 μm to about 500 μm, or about 250 μm to about 750 μm, or about 500 μm to about 1000 μm).

[0143] The time for maintaining the temperature and shear rate for the formation of process 112 and the molten emulsion 114 may be from 10 seconds to 18 hours or more (or 10 seconds to 30 minutes, or 5 minutes to 1 hour, or 15 minutes to 2 hours, or 1 hour to 6 hours, or 3 hours to 18 hours). Without being bound by theory, it is considered that the steady state of the droplet diameter is reached at the point when process 112 can be stopped. That time may depend, inter alia, on the temperature, shear rate, composition of the thermoplastic polymer 102, composition of the dispersion medium 104, and composition of the emulsifying stabilizer 106.

[0144] The molten emulsion 114 may then be cooled at 116. The cooling at 116 can be from low speed (for example, enabling the cooling of the molten emulsion under ambient conditions) to high speed (for example, quenching). For example, the cooling rate may be in the range of about 10 °C / hour to about 100 °C / second, and further even almost instantaneous by quenching (for example, dry ice) (or about 10 °C / hour to about 60 °C / hour, or about 0.5 °C / minute to about 20 °C / minute, or about 1 °C / minute to about 5 °C / minute, or about 10 °C / minute to about 60 °C / minute, or about 0.5 °C / second to about 10 °C / second, or about 10 °C / second to about 100 °C / second).

[0145] During cooling, little or no shear force may be applied to the molten emulsion 114. In some cases, the shear force applied during heating may be applied during cooling.

[0146] The cooled mixture 118 obtained from the cooling 116 of the molten emulsion 114 comprises solidified thermoplastic polymer particles 122 (or simply thermoplastic polymer particles) and other constituents 124 (such as the dispersion medium 104, the excess emulsifying stabilizer 106, etc.). The thermoplastic polymer particles may be dispersed in the dispersion medium or may sediment in the dispersion medium.

[0147] The cooled mixture 118 may then be treated (120) to separate the thermoplastic polymer particles 122 (or simply the thermoplastic polymer particles 122) from the other constituents 124. Suitable treatments include, but are not limited to, washing, filtration, centrifugation, and decantation, as well as any combination thereof.

[0148] The solvent used to wash the thermoplastic polymer particles 122 should generally be (a) miscible with the dispersion medium 104 and (b) non-reactive with the thermoplastic polymer 102 (e.g., non-swelling and non-melting). The choice of solvent will depend, inter alia, on the composition of the dispersion medium and the composition of the thermoplastic polymer 102.

[0149] Examples of solvents include, but are not limited to, hydrocarbon solvents (such as pentane, hexane, heptane, octane, cyclohexane, cyclopentane, decane, dodecane, tridecane, and tetradecane), aromatic hydrocarbon solvents (such as benzene, toluene, xylene, 2-methylnaphthalene, and cresol), ether solvents (such as diethyl ether, tetrahydrofuran, diisopropyl ether, and dioxane), ketone solvents (such as acetone and methyl ethyl ketone), alcohol solvents (such as methanol, ethanol, isopropanol, and n-propanol), ester solvents (such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate, and butyl butyrate), halogenated solvents (such as chloroform, bromoform, 1,2-dichloromethane, 1,2-dichloroethane, carbon tetrachloride, chlorobenzene, and hexafluoroisopropanol), water, etc., as well as any combination thereof.

[0150] The solvent may be removed from the thermoplastic polymer particles 122 by drying using a suitable method such as air drying, heat drying, vacuum drying, freeze drying, or a hybrid thereof. The heating may preferably be carried out at a temperature lower than the glass transition temperature of the thermoplastic polymer (for example, about 50°C to about 150°C).

[0151] The thermoplastic polymer particles 122 after separation from the other components 124 may optionally be further classified to produce purified thermoplastic polymer particles 128. For example, to narrow the particle size distribution (or reduce the diameter span), the thermoplastic polymer particles 122 may be passed through a sieve having a pore size of about 10 μm to about 250 μm (or about 10 μm to about 100 μm, or about 50 μm to about 200 μm, or about 150 μm to about 250 μm).

[0152] In another example of a purification technique, the thermoplastic polymer particles 122 may be washed with water to remove the surfactant while maintaining substantially all of the nanoparticles associated with the surface of the thermoplastic polymer particles 122. In yet another example of a purification technique, the thermoplastic polymer particles 122 may be blended with additives to obtain the desired final product. For clarity, such additives are referred to herein as "external additives" because they are blended with the thermoplastic particles 122 or other particles obtained from the methods described herein after the particles have solidified. Examples of external additives include flow aids, other polymer particles, fillers, etc., and any combination thereof.

[0153] In some cases, the surfactant used in the production of the thermoplastic polymer particles 122 may be unnecessary in downstream applications. Accordingly, yet another example of a purification technique may include at least substantially removing the surfactant from the thermoplastic polymer particles 122 (for example, by washing and / or pyrolysis).

[0154] The thermoplastic polymer particles 122 and / or the purified thermoplastic polymer particles 128 (referred to as particles 122 / 128) can be characterized by their composition, physical structure, etc.

[0155] As described above, the emulsifying stabilizer is at the interface between the polymer melt and the dispersion medium. As a result, when the mixture is cooled, the emulsifying stabilizer remains at or near the interface. Thus, the structure of the particles 122 / 128 generally includes (a) an emulsifying stabilizer dispersed on the outer surface of the particles 122 / 128 and / or (b) an emulsifying stabilizer embedded in the outer portion (e.g., the outer 1% by volume) of the particles 122 / 128.

[0156] Furthermore, when voids are formed inside the polymer melt droplets, the emulsifying stabilizer 106 should generally be present (and / or embedded) at the interface between the inside of the voids and the thermoplastic polymer. The voids generally do not contain thermoplastic polymer. Rather, the voids can contain, for example, the dispersion medium, air, or be empty. The particles 122 / 128 can contain up to about 5% by weight (or from about 0.001% by weight to about 5% by weight, or from about 0.001% by weight to about 0.1% by weight, or from about 0.01% by weight to about 0.5% by weight, or from about 0.1% by weight to about 2% by weight, or from about 1% by weight to about 5% by weight) of the dispersion medium.

[0157] The thermoplastic polymer 102 can be present in the particles 122 / 128 at about 90% to about 99.5% by weight (or from about 90% to about 95% by weight, or from about 92% to about 97% by weight, or from about 95% to about 99.5% by weight) of the particles 122 / 128.

[0158] When included, the emulsifying stabilizer 106 may be present in the particles 122 / 128 at about 10 wt% or less (or about 0.01 wt% to about 10 wt%, or about 0.01 wt% to about 1 wt%, or about 0.5 wt% to about 5 wt%, or about 3 wt% to about 7 wt%, or about 5 wt% to about 10 wt%) of the particles 122 / 128. When purified to at least substantially remove surfactants or another emulsifying stabilizer, the emulsifying stabilizer 106 may be present in the particles 128 at less than 0.01 wt% (or 0 wt% to about 0.01 wt%, or 0 wt% to 0.001 wt%).

[0159] When forming the thermoplastic microparticles according to the disclosure of this specification, at least a portion of the nanoparticles such as silica nanoparticles can be disposed as a coating on the outer surface of the thermoplastic microparticles. At least a portion of the surfactant, when used, can likewise associate with the outer surface. The coating can be disposed substantially uniformly on the outer surface. As used herein with respect to the coating, the term "substantially uniform" refers to a uniform coating thickness at the surface positions covered by the coating composition (e.g., nanoparticles and / or surfactant), particularly across the entire outer surface. The emulsifier stabilizer 106 can form a coating that covers at least 5% (or about 5% to about 100%, or about 5% to about 25%, or about 20% to about 50%, or about 40% to about 70%, or about 50% to about 80%, or about 60% to about 90%, or about 70% to about 100%) of the surface area of the particles 122 / 128. When purified to at least substantially remove the surfactant or another emulsifier stabilizer, the emulsifier stabilizer 106 can be present in the particles 128 at less than 25% (or 0% to about 25%, or about 0.1% to about 5%, or about 0.1% to about 1%, or about 1% to about 5%, or about 1% to about 10%, or about 5% to about 15%, or about 10% to about 25%) of the surface area of the particles 128. The coverage rate of the emulsifier stabilizer 106 on the outer surface of the particles 122 / 128 can be determined using image analysis of a scanning electron microscope image (SEM micrograph). The emulsifier stabilizer 106 can form a coating that covers at least 5% (or about 5% to about 100%, or about 5% to about 25%, or about 20% to about 50%, or about 40% to about 70%, or about 50% to about 80%, or about 60% to about 90%, or about 70% to about 100%) of the surface area of the particles 122 / 128. When purified to at least substantially remove the surfactant or another emulsifier stabilizer, the emulsifier stabilizer 106 can be present in the particles 128 at less than 25% (or 0% to about 25%, or about 0.1% to about 5%, or about 0.1% to about 1%, or about 1% to about 5%, or about 1% to about 10%, or about 5% to about 15%, or about 10% to about 25%) of the surface area of the particles 128. The coverage rate of the emulsifier stabilizer 106 on the outer surface of the particles 122 / 128 can be determined using image analysis of SEM micrographs.

[0160] The particles 122 / 128 may have a D10 of about 0.1 μm to about 125 μm (or about 0.1 μm to about 5 μm, about 1 μm to about 10 μm, about 5 μm to about 30 μm, or about 1 μm to about 25 μm, or about 25 μm to about 75 μm, or about 50 μm to about 85 μm, or about 75 μm to about 125 μm), a D50 of about 0.5 μm to about 200 μm (or about 0.5 μm to about 10 μm, or about 5 μm to about 50 μm, or about 30 μm to about 100 μm, or about 30 μm to about 70 μm, or about 25 μm to about 50 μm, or about 50 μm to about 100 μm, or about 75 μm to about 150 μm, or about 100 μm to about 200 μm), and a D90 of about 3 μm to about 300 μm (or about 3 μm to about 15 μm, or about 10 μm to about 50 μm, or about 25 μm to about 75 μm, or about 70 μm to about 200 μm, or about 60 μm to about 150 μm, or about 150 μm to about 300 μm), with D10 < D50 < D90. The particles 122 / 128 may also have a diameter span of about 0.4 to about 3 (or about 0.6 to about 2, or about 0.4 to about 1.5, or about 1 to about 3). Without limitation, a diameter span value of 1.0 or greater is considered wide, and a diameter span value of 0.75 or less is considered narrow. For example, the particles 122 / 128 may have a D10 of about 5 μm to about 30 μm, a D50 of about 30 μm to about 100 μm, and a D90 of about 70 μm to about 120 μm, with D10 < D50 < D90.

[0161] The particles 122 / 128 may also have a diameter span of about 0.4 to about 3 (or about 0.6 to about 2, or about 0.4 to about 1.5, or about 1 to about 3).

[0162] In a first non-limiting example, the particles 122 / 128 may have a D10 of about 0.5 μm to about 5 μm, a D50 of about 0.5 μm to about 10 μm, and a D90 of about 3 μm to about 15 μm, with D10 < D50 < D90.

[0163] In a second non-limiting example, the particles 122 / 128 may have a D10 of about 1 μm to about 50 μm, a D50 of about 25 μm to about 100 μm, and a D90 of about 60 μm to about 300 μm, with D10 < D50 < D90.

[0164] In a third non-limiting example, the particles 122 / 128 can have a D10 of about 5 μm to about 30 μm, a D50 of about 30 μm to about 70 μm, and a D90 of about 70 μm to about 120 μm, with D10 < D50 < D90. The particles 122 / 128 can have a diameter span of about 1.0 to about 2.5.

[0165] In a fourth non-limiting example, the particles 122 / 128 can have a D10 of about 25 μm to about 60 μm, a D50 of about 60 μm to about 110 μm, and a D90 of about 110 μm to about 175 μm, with D10 < D50 < D90. The particles 122 / 128 can have a diameter span of about 0.6 to about 1.5.

[0166] In a fifth non-limiting example, the particles 122 / 128 can have a D10 of about 75 μm to about 125 μm, a D50 of about 100 μm to about 200 μm, and a D90 of about 125 μm to about 300 μm, with D10 < D50 < D90. The particles 122 / 128 can have a diameter span of about 0.2 to about 1.2.

[0167] The particles 122 / 128 can have a circularity of about 0.7 or more (or 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).

[0168] The particles 122 / 128 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°).

[0169] The particles 122 / 128 can have a Hausner ratio of about 1.0 to about 1.5 (or about 1.0 to about 1.2, or about 1.1 to about 1.3, or about 1.2 to about 1.35, or about 1.3 to about 1.5).

[0170] The particles 122 / 128 are about 0.3 g / cm 3 ~ about 0.8 g / cm 3 (or about 0.3 g / cm 3 ~ about 0.6 g / cm 3 , or about 0.4 g / cm 3 ~ about 0.7 g / cm3 or about 0.5 g / cm 3 ~ about 0.6 g / cm 3 or about 0.5 g / cm 3 ~ about 0.8 g / cm 3 ) and may have a bulk density of

[0171] Depending on the temperature and shear rate of process 112, and the composition and relative concentrations of components 102, 104, and 106, different shapes of the structure constituting particles 122 / 128 have been observed. Typically, particles 122 / 128 include substantially spherical particles (having a circularity of about 0.97 or more). However, in particles 122 / 128, other structures including disk structures and elongated structures have been observed. Thus, particles 122 / 128 may include one or more of (a) substantially spherical particles having a circularity of 0.97 or more, (b) disk structures having an aspect ratio of about 2 to about 10, and (c) elongated structures having an aspect ratio of 10 or more. Each of the above (a), (b), and (c) structures has an emulsifier stabilizer dispersed on the outer surface of the (a), (b), and (c) structures and / or an emulsifier stabilizer embedded in the outer portion of the (a), (b), and (c) structures. At least some of the (a), (b), and (c) structures may aggregate. For example, the elongated structure of (c) may be located on the surface of the substantially spherical particles of (a).

[0172] Particles 122 / 128 may have a sintering window within 10 °C, preferably within 5 °C, of the sintering window of the thermoplastic polymer 102.

[0173] Non-limiting examples

[0174] A first non-limiting exemplary embodiment of the present disclosure is a composition comprising particles comprising an unsaturated polyamide and an initiator. The first non-limiting exemplary embodiment includes Element 1: the particles have a circularity of about 0.9 to about 1.0, Element 2: the weight ratio of the unsaturated polyamide to the initiator is about 90:10 to about 99:1, Element 3: the particles further comprise an infrared absorber, Element 4: the composition further comprises an infrared absorber mixed with the particles, Element 5: the particles further comprise a thermoplastic polymer that is not an unsaturated polyamide, Element 6: the particles further comprise an emulsifying stabilizer associated with the outer surface of the particles, Element 7: Element 6, wherein at least some of the particles have voids containing the emulsifying stabilizer at the void / polymer interface, Element 8: Element 6, wherein the emulsifying stabilizer comprises nanoparticles and the nanoparticles are embedded in the outer surface of the particles, Element 9: the particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, with D10 < D50 < D90, Element 10: the particles have a diameter span of about 0.2 to about 10, and Element 11: the solidified particles have a Hausner ratio of about 1.0 to about 1.5, and may further include one or more of the above. Examples of combinations include, but are not limited to, Element 1 in combination with one or more of Elements 2-11, Element 2 in combination with one or more of Elements 3-11, Element 3 in combination with one or more of Elements 4-11, Element 4 in combination with one or more of Elements 5-11, Element 6 (optionally in combination with Elements 7 and / or 8) in combination with one or more of Elements 9-11, and combinations of two or more of Elements 9-11.

[0175] A second non-limiting exemplary embodiment includes depositing, on a surface, a composition of the first non-limiting exemplary embodiment (optionally having one or more of Elements 1-11) optionally in combination with other thermoplastic polymer particles, and after deposition, heating at least a portion of the particles to promote their densification and crosslinking of the unsaturated polyamide, thereby forming a compact comprising a crosslinked polyamide.

[0176] A third non-limiting exemplary embodiment involves mixing a mixture comprising an unsaturated polyamide, a dispersion medium immiscible with the unsaturated polyamide, and optionally an emulsifying stabilizer, at a temperature above the melting point or softening temperature of the unsaturated polyamide and at a shear rate high enough to disperse the unsaturated polyamide in the dispersion medium, and then cooling the mixture to below the melting point or softening temperature of the unsaturated polyamide to form unsaturated polyamide particles comprising the unsaturated polyamide and, if present, an emulsifying stabilizer associated with the outer surface of the unsaturated polyamide particles. The first non-limiting exemplary embodiment further includes elements 1, 9, 10, 11, 12: the method further comprises dry blending the unsaturated polyamide particles with an initiator, and the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99:1; element 13: the method further comprises wet blending the unsaturated polyamide particles with an initiator, and the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99; element 14: the initiator is a photoinitiator; element 15: the initiator is a thermal initiator; element 16: the mixture further comprises a thermoplastic polymer other than the unsaturated polyamide; element 17: the mixture further comprises an infrared absorber; element 18: the emulsifying stabilizer is included in the mixture and is associated with the outer surface of the unsaturated polyamide particles; element 19: element 18, wherein the emulsifying stabilizer comprises nanoparticles and the nanoparticles are embedded in the outer surface of the unsaturated polyamide particles; and element 20: the mixture further comprises an initiator, and the weight ratio of the initiator to the unsaturated polyamide is from about 90:10 to about 99:1, and may further include one or more of the above.Examples of combinations include, but are not limited to, combinations of two or more of elements 12, 13, and 20; element 1 combined with one or more of elements 9 - 20; element 9 combined with one or more of elements 10 - 20; element 10 combined with one or more of elements 11 - 20; element 11 combined with one or more of elements 12 - 20; element 12 combined with one or more of elements 13 - 20; element 13 combined with one or more of elements 14 - 20; element 14 combined with one or more of elements 15 - 20; element 15 combined with one or more of elements 16 - 20; element 16 combined with one or more of elements 17 - 20; and combinations of two or more of elements 18 - 20.

[0177] A fourth non - limiting exemplary embodiment is emulsion polymerization via polycondensation and / or ring - opening reaction between a first polyamide monomer and a second polyamide monomer, wherein the second polyamide monomer contains at least one unsaturated aliphatic carbon - carbon bond for producing an unsaturated polyamide, the method comprising emulsion polymerization, precipitating the unsaturated polyamide as particles, and blending the particles containing the unsaturated polyamide with an initiator. The fourth non - limiting exemplary embodiment may include one or more of element 21: the blend includes a dry blend; element 22: the blend includes a wet blend; element 23: the initiator is a photo - initiator; element 24: the initiator is a thermal initiator; and element 25: the method further includes blending the particles containing the unsaturated polyamide with an infrared absorber.

[0178] The fifth non-limiting exemplary embodiment is a method comprising dissolving an unsaturated polyamide in a solvent, precipitating the unsaturated polyamide as particles, and blending the particles containing the unsaturated polyamide with an initiator. The fifth non-limiting exemplary embodiment may include one or more of element 26: the blend includes a dry blend, element 27: the blend includes a wet blend, element 28: the initiator is a photoinitiator, element 29: the initiator is a thermal initiator, and element 30: the method further includes blending the particles containing the unsaturated polyamide with an infrared absorber.

[0179] The sixth non-limiting exemplary embodiment is a method comprising dissolving an unsaturated polyamide in a solvent, precipitating the unsaturated polyamide as particles, and blending the particles containing the unsaturated polyamide with an initiator. The sixth non-limiting exemplary embodiment may include one or more of element 31: the blend includes a dry blend, element 32: the blend includes a wet blend, element 33: the initiator is a photoinitiator, element 34: the initiator is a thermal initiator, and element 35: the method further includes blending the particles containing the unsaturated polyamide with an infrared absorber.

[0180] The seventh non-limiting exemplary embodiment is a method comprising dissolving an unsaturated polyamide and an initiator in a solvent and precipitating the unsaturated polyamide to obtain particles containing the unsaturated polyamide and the initiator. The seventh non-limiting exemplary embodiment may include one or more of element 36: further including dry blending the particles containing the unsaturated polyamide and the initiator with another initiator (the same as or different from the initiator), element 37: further including wet blending the particles containing the unsaturated polyamide and the initiator with another initiator (the same as or different from the initiator), element 38: the initiator is a photoinitiator, element 39: the initiator is a thermal initiator, and element 40: the method further includes blending the particles containing the unsaturated polyamide and the initiator with an infrared absorber.

[0181] The eighth non-limiting exemplary embodiment is a method including cooling an unsaturated polyamide at a low temperature, milling the low-temperature cooled unsaturated polyamide to obtain particles, and blending the particles containing the unsaturated polyamide with an initiator. The sixth non-limiting exemplary embodiment may include one or more of element 41: the blend includes a dry blend, element 42: the blend includes a wet blend, element 43: the initiator is a photoinitiator, element 44: the initiator is a thermal initiator, and element 45: the method further includes blending the particles containing the unsaturated polyamide with an infrared absorber.

[0182] The ninth non-limiting exemplary embodiment is a method including cooling an unsaturated polyamide at a low temperature in the presence of an initiator, and milling the low-temperature cooled unsaturated polyamide to obtain particles containing the unsaturated polyamide and the initiator. The ninth non-limiting exemplary embodiment may include one or more of element 46: further dry blending the particles containing the unsaturated polyamide and the initiator with another initiator (the same as or different from the initiator), element 47: further wet blending the particles containing the unsaturated polyamide and the initiator with another initiator (the same as or different from the initiator), element 48: the initiator is a photoinitiator, element 49: the initiator is a thermal initiator, and element 50: the method further includes blending the particles containing the unsaturated polyamide and the initiator with an infrared absorber.

[0183] The tenth non-limiting exemplary embodiment is a method including melt-emulsifying an unsaturated polyamide, cooling the melt emulsion to obtain particles, and blending the particles containing the unsaturated polyamide with an initiator. The tenth non-limiting exemplary embodiment may include one or more of element 51: the blend includes a dry blend, element 52: the blend includes a wet blend, element 53: the initiator is a photoinitiator, element 54: the initiator is a thermal initiator, and element 55: the method further includes blending the particles containing the unsaturated polyamide with an infrared absorber.

[0184] The 11th non-limiting exemplary embodiment is a method that includes melt-emulsifying an unsaturated polyamide in the presence of an initiator and cooling the melt emulsion to obtain particles containing the unsaturated polyamide and the initiator. The 11th non-limiting exemplary embodiment may further include one or more of Element 56: dry blending the particles containing the unsaturated polyamide and the initiator with another initiator (the same as or different from the initiator), Element 57: wet blending the particles containing the unsaturated polyamide and the initiator with another initiator (the same as or different from the initiator), Element 58: the initiator being a photoinitiator, Element 59: the initiator being a thermal initiator, and Element 60: the method further including blending the particles containing the unsaturated polyamide and the initiator with an infrared absorber.

[0185] Additional non-limiting exemplary embodiments include depositing a composition prepared according to one or more of the 4th to 11th non-limiting exemplary embodiments on a surface, optionally in combination with other thermoplastic polymer particles, and after deposition, heating at least a portion of the particles to promote their consolidation and crosslinking of the unsaturated polyamide, thereby forming a consolidated body containing the crosslinked polyamide.

[0186] Clause

[0187] Clause 1. A composition comprising particles containing an unsaturated polyamide and an initiator.

[0188] Clause 2. The composition according to Clause 1, wherein the particles have a circularity of about 0.9 to about 1.0.

[0189] Clause 3. The composition according to Clause 1, wherein the weight ratio of the unsaturated polyamide to the initiator is about 90:10 to about 99:1.

[0190] Clause 4. The composition according to Clause 1, wherein the particles further contain an infrared absorber.

[0191] Clause 5. The composition according to Clause 1, further comprising an infrared absorber mixed with the particles.

[0192] Clause 6. The composition according to Clause 1, wherein the particles further comprise a thermoplastic polymer that is not an unsaturated polyamide.

[0193] Clause 7. The composition according to Clause 1, wherein the particles further comprise an emulsifying stabilizer associated with the outer surface of the particles.

[0194] Clause 8. The composition according to Clause 7, wherein at least some of the particles have voids containing an emulsifying stabilizer at the void / polymer interface.

[0195] Clause 9. The composition according to Clause 7, wherein the emulsifying stabilizer comprises nanoparticles, and the nanoparticles are embedded in the outer surface of the particles.

[0196] Clause 10. A method comprising depositing the composition according to Clause 1 optionally in combination with other thermoplastic polymer particles on a surface, and after deposition, heating at least a portion of the particles to promote their consolidation and crosslinking of the unsaturated polyamide, thereby forming a consolidated body containing crosslinked polyamide.

[0197] Clause 11. A method comprising mixing a mixture comprising an unsaturated polyamide, a dispersion medium immiscible with the unsaturated polyamide, and optionally an emulsifying stabilizer at a temperature above the melting point or softening temperature of the unsaturated polyamide and at a shear rate high enough to disperse the unsaturated polyamide in the dispersion medium, and cooling the mixture to below the melting point or softening temperature of the unsaturated polyamide to form unsaturated polyamide particles comprising the unsaturated polyamide and, if present, an emulsifying stabilizer associated with the outer surface of the unsaturated polyamide particles.

[0198] Clause 12. The method according to Clause 11, further comprising dry blending the unsaturated polyamide particles with an initiator, wherein the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99:1.

[0199] Clause 13. The method according to Clause 11, further comprising wet blending unsaturated polyamide particles with an initiator, wherein the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99:1.

[0200] Clause 14. The method according to Clause 11, wherein the initiator is a photoinitiator.

[0201] Clause 15. The method according to Clause 11, wherein the initiator is a thermal initiator.

[0202] Clause 16. The method according to Clause 11, wherein the mixture further comprises a thermoplastic polymer that is not an unsaturated polyamide.

[0203] Clause 17. The method according to Clause 11, wherein the mixture further comprises an infrared absorber.

[0204] Clause 18. The method according to Clause 11, wherein an emulsifying stabilizer is included in the mixture and the emulsifying stabilizer is associated with the outer surface of the unsaturated polyamide particles.

[0205] Clause 19. The method according to Clause 18, wherein the emulsifying stabilizer comprises nanoparticles and the nanoparticles are embedded in the outer surface of the unsaturated polyamide particles.

[0206] Clause 20. The method according to Clause 11, wherein the mixture further comprises an initiator, and the weight ratio of the initiator to the unsaturated polyamide is from about 90:10 to about 99:1.

[0207] Clause 21. A method comprising emulsion polymerization via polycondensation and / or ring-opening reaction between a first polyamide monomer and a second polyamide monomer, wherein the second polyamide monomer comprises at least one unsaturated aliphatic carbon-carbon bond for producing an unsaturated polyamide, precipitating the unsaturated polyamide as particles, and blending the particles containing the unsaturated polyamide with an initiator.

[0208] Clause 22. The method according to Clause 21, wherein the blend comprises a dry blend.

[0209] Clause 23. The method according to clause 21, wherein the blend comprises a wet blend.

[0210] Clause 24. The method according to clause 21, wherein the initiator is a photoinitiator.

[0211] Clause 25. The method according to clause 21, wherein the initiator is a thermal initiator.

[0212] Clause 26. The method according to clause 21, further comprising blending particles comprising an unsaturated polyamide with an infrared absorber.

[0213] Clause 27. A method comprising dissolving an unsaturated polyamide in a solvent, precipitating the unsaturated polyamide as particles, and blending the particles comprising the unsaturated polyamide with an initiator.

[0214] Clause 28. The method according to clause 27, wherein the blend comprises a dry blend.

[0215] Clause 29. The method according to clause 27, wherein the blend comprises a wet blend.

[0216] Clause 30. The method according to clause 27, wherein the initiator is a photoinitiator.

[0217] Clause 31. The method according to clause 27, wherein the initiator is a thermal initiator.

[0218] Clause 32. The method according to clause 27, further comprising blending particles comprising an unsaturated polyamide with an infrared absorber.

[0219] Clause 33. A method comprising:

[0220] dissolving an unsaturated polyamide and an initiator in a solvent; and

[0221] precipitating the unsaturated polyamide to obtain particles comprising the unsaturated polyamide and the initiator.

[0222] Clause 34. The method according to clause 33, further comprising dry blending particles containing an unsaturated polyamide and an initiator with a second initiator.

[0223] Clause 35. The method according to clause 33, further comprising wet blending particles containing an unsaturated polyamide and an initiator with a second initiator.

[0224] Clause 36. The method according to clause 33, wherein the initiator is a photoinitiator.

[0225] Clause 37. The method according to clause 33, wherein the initiator is a thermal initiator.

[0226] Clause 38. The method according to clause 33, further comprising blending particles containing an unsaturated polyamide and an initiator with an infrared absorber.

[0227] Clause 39. A method comprising cooling an unsaturated polyamide to a low temperature, pulverizing the low-temperature cooled unsaturated polyamide to obtain particles, and blending the particles containing the unsaturated polyamide with an initiator.

[0228] Clause 40. The method according to clause 39, wherein the blend comprises a dry blend.

[0229] Clause 41. The method according to clause 39, wherein the blend comprises a wet blend.

[0230] Clause 42. The method according to clause 39, wherein the initiator is a photoinitiator.

[0231] Clause 43. The method according to clause 39, wherein the initiator is a thermal initiator.

[0232] Clause 44. The method according to clause 39, further comprising blending the particles containing the unsaturated polyamide with an infrared absorber.

[0233] Clause 45. A method comprising: cooling an unsaturated polyamide at a low temperature in the presence of an initiator; and pulverizing the low-temperature cooled unsaturated polyamide to obtain particles containing the unsaturated polyamide and the initiator.

[0234] Clause 46. The method according to clause 45, further comprising dry-blending the particles containing the unsaturated polyamide and the initiator with a second initiator.

[0235] Clause 47. The method according to clause 45, further comprising wet-blending the particles containing the unsaturated polyamide and the initiator with a second initiator.

[0236] Clause 48. The method according to clause 45, wherein the initiator is a photoinitiator.

[0237] Clause 49. The method according to clause 45, wherein the initiator is a thermal initiator.

[0238] Clause 50. The method according to clause 45, further comprising blending the particles containing the unsaturated polyamide and the initiator with an infrared absorber.

[0239] Clause 51. A method comprising: melt-emulsifying an unsaturated polyamide; cooling the melt emulsion to obtain particles; and blending the particles containing the unsaturated polyamide with an initiator.

[0240] Clause 52. The method according to clause 51, wherein the blend comprises a dry blend.

[0241] Clause 53. The method according to clause 51, wherein the blend comprises a wet blend.

[0242] Clause 54. The method according to clause 51, wherein the initiator is a photoinitiator.

[0243] Clause 55. The method according to clause 51, wherein the initiator is a thermal initiator.

[0244] The method according to item 51, further comprising blending particles containing an unsaturated polyamide with an infrared absorber.

[0245] Item 57. A method comprising melting and emulsifying an unsaturated polyamide in the presence of an initiator, and cooling the melt emulsion to obtain particles containing the unsaturated polyamide and the initiator.

[0246] Item 28. The method according to item 57, further comprising dry-blending particles containing an unsaturated polyamide and an initiator with a second initiator.

[0247] Item 59. The method according to item 57, further comprising wet-blending particles containing an unsaturated polyamide and an initiator with a second initiator.

[0248] Item 60. The method according to item 57, wherein the initiator is a photoinitiator.

[0249] Item 61. The method according to item 57, wherein the initiator is a thermal initiator.

[0250] Item 62. The method according to item 57, further comprising blending particles containing an unsaturated polyamide and an initiator with an infrared absorber.

[0251] Unless otherwise specified, all numbers representing properties such as components, molecular weights, and amounts such as reaction conditions used in this specification and the related patent claims should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters described in the following specification and the appended patent claims are approximate values that may vary depending on the desired properties considered to be obtained by the implementation of the present invention. At a minimum, and not to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed by applying the ordinary rounding method in light of the number of significant figures reported.

[0252] One or more exemplary implementations incorporating one or more inventive elements are presented herein. For clarity, not all features of a physical implementation are described or shown in this application. In developing a physical embodiment incorporating one or more elements of the present invention, it will be understood that numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related, and other constraints, which may vary and change over time. Although the developer's efforts may be time-consuming, such efforts are routine for those of ordinary skill in the art and will yield the benefits of this disclosure.

[0253] Compositions and methods are described herein using the term "comprising" various components or steps, but the compositions and methods may also "consist essentially of" or "consist of" various components and steps.

[0254] To facilitate a better understanding of embodiments of the present invention, the following examples of preferred or representative embodiments are provided. The following examples should not be read to limit or define the scope of the present invention.

Examples

[0255] Synthesis of unsaturated polyamide by interfacial polycondensation will be described. The interfacial polycondensation can be carried out at a constant speed of 2000 RPM in a 2 L glass container equipped with an overhead stirrer. A 500 mL solution of dichloride fumarate in toluene with a concentration of 0.2 mol (M) may be added to a stirred container containing 500 mL of an aqueous suspension of 4,4’-methylenedianiline (MDA) at 0.2 M. The aqueous suspension of MDA may be mixed with KOH in the form of a 0.5 normal (N) solution added to the aqueous phase at a rate of 1 mol of KOH per 1 mol of MDA to ensure the maximum molecular weight of the polyamide. After mixing the solution at 20 °C ± 2 °C for 30 minutes, a concentrated solution should be formed. After distilling off toluene by rotary evaporation under pressure or under steam, the polymer should be in the form of a thin film. This film may be ground and washed with a large amount of water until no chlorine is detected in the effluent water. The polymer may be further washed to remove residual monomers using hot 30% methanol and then dried in a vacuum oven. The melting point of the resulting polymer (Polymer A) should be about 230 °C.

Chemical formula

[0256] Synthesis of unsaturated polyamides from dicarboxylic acids will be described where aliphatic and aromatic dicarboxylic acids can react directly with 1,5-bis(3-aminophenyl)-1,4-pentadien-3-one (DADBA). These monomers may be reacted in a polar solvent at low temperature (e.g., about 10 °C or lower) in the presence of thionyl chloride. An exemplary synthetic procedure can be carried out by adding 21.9 g (150 mmol) of adipic acid in 300 mL of dimethylformamide (DMF) to a 2 L glass kettle equipped with an overhead stirrer, a thermocouple, and a nitrogen purge. The mixture may then be cooled to -5 °C in a NaNO3 / ice bath while simultaneously adding 35.7 g (300 mmol) of thionyl chloride with stirring. After about 1 - 2 minutes, 39.6 g (150 mmol) of DADBA and 30.3 g (300 mmol) of triethyl amine (TEA) are added to the mixture and stirred at 0 °C - 5 °C for 10 hours. After the reaction is complete, the polymer solution may be poured into an ice bath and immediately filtered. The polymer may then be washed several times with cold water and ethanol. If the DMF solution is removed for further purification, methanol may be used as a non-solvent. The melting point of the resulting polymer (Polymer B) should be about 220 °C.

Chemical formula

[0257] Comparative Example 3 Unsaturated polyamides may also be produced by low-temperature polymerization by reacting diacid chlorides of aliphatic and aromatic dicarboxylic acids directly with DADBA. An exemplary synthetic procedure can be carried out by adding 27.3 g (150 mmol) of adipoyl chloride in 300 mL of N-methyl pyrrolidone (NMP) to a glass kettle equipped with an overhead stirrer, a thermocouple, and a nitrogen purge. The mixture may then be cooled to -5 °C in a NaNO3 / ice bath, and simultaneously 39.6 g (150 mmol) of DADBA and 30.3 g (300 mmol) of triethylamine (TEA) are added to the mixture, and the mixture is stirred at 0 °C to 5 °C for 10 hours. After the reaction is complete, the polymer solution may be poured into an ice bath and immediately filtered. The polymer may then be washed with ethanol and chloroform. The final purification step may include dissolving the polymer in DMF and subsequently precipitating it in methanol. The melting point of the resulting polymer (Polymer B) should be about 220 °C.

[0258] The comparative example 4 microparticles can be produced from the unsaturated polyamides synthesized in comparative examples 1 to 3 in a Haake small-scale twin-screw extruder having a high-shear rotor. The dispersion medium may be the dispersion media described herein (e.g., PDMS oil having a viscosity of about 10,000 cSt to about 30,000 cSt at room temperature). First, a dispersion medium in which 1 wt% of AEROSIL® R812S silica nanoparticles (relative to the polymer) is dispersed may be added and brought to a temperature near the melting point of the polymer. Then, room-temperature polymer pellets of the unsaturated polyamide and an initiator (preferably, when thermally triggered, an initiator having an activation energy higher than the melting emulsification temperature) may be added to the heated dispersion medium in the extruder. The weight ratio of the dispersion medium to the polyamide may be about 60:40 to about 80:20. The weight ratio of the polyamide to the initiator may be about 90:10 to about 99:1. In terms of temperature, the extruder may be operated at about 200 rpm for about 20 minutes to about 30 minutes. Then, the mixture can be discharged from the extruder onto a low-temperature surface for rapid cooling. The oil may be washed away from the unsaturated polyamide microparticles using ethyl acetate and filtered from the oil / ethyl acetate mixture. The washing procedure may include three washes with about 200 mL to about 500 mL of ethyl acetate at room temperature. The particles may be separated from the solvent by vacuum filtration onto Whatman #1, 90 mm filter paper. Then, the microparticles can be air-dried overnight in an aluminum pan in a fume hood to evaporate the residual ethyl acetate. The final unsaturated polyamide particles should have a D50 of about 30 microns to about 70 microns and a span of about 0.9 to about 1.3.

[0259] Comparative Example 5 The microparticles can be produced from the unsaturated polyamides synthesized in Comparative Examples 1 to 3 in a Haake small-scale twin-screw extruder having a high-shear rotor. The dispersion medium may be the dispersion media described herein (e.g., PDMS oil having a viscosity of about 10,000 cSt to about 30,000 cSt at room temperature). To mitigate premature crosslinking of the polymer during melt emulsification, a dispersion medium in which 1 wt% AEROSIL® R812S silica nanoparticles (relative to the polymer) are dispersed may be added first and brought to a temperature near the melting point of the polymer. Subsequently, room-temperature polymer pellets of the unsaturated polyamide may be added to the heated dispersion medium in the extruder. The weight ratio of the dispersion medium to the polyamide may be from about 60:40 to about 80:20. In terms of temperature, the extruder may be operated at about 200 rpm for about 20 minutes to about 30 minutes. Subsequently, the mixture can be discharged from the extruder onto a cold surface for rapid cooling. The oil may be washed away from the unsaturated polyamide microparticles using ethyl acetate and filtered from the oil / ethyl acetate mixture. The washing procedure may include three washes with about 200 mL to about 500 mL of ethyl acetate at room temperature. The particles may be separated from the solvent by vacuum filtration onto Whatman #1, 90 mm filter paper. Subsequently, the microparticles can be air-dried overnight in an aluminum pan in a fume hood to evaporate the residual ethyl acetate. The final unsaturated polyamide particles will have a D50 of about 30 microns to about 70 microns and a span of about 0.9 to about 1.3.

[0260] Subsequently, the resulting unsaturated polyamide particles may be dry-blended with an initiator. The weight ratio of the polyamide to the initiator may be from about 90:10 to about 99:1.

[0261] The comparative example 6 microparticles can be produced from the unsaturated polyamides synthesized in comparative examples 1 to 3 in a Haake small-scale twin-screw extruder having a high-shear rotor. The dispersion medium may be the dispersion media described herein (e.g., PDMS oil having a viscosity of about 10,000 cSt to about 30,000 cSt at room temperature). To mitigate the premature cross-linking of the polymer during melt emulsification, a dispersion medium in which 1 wt% of AEROSIL® R812S silica nanoparticles (relative to the polymer) are dispersed may be added first, and the temperature may be set to near the melting point of the polymer. Subsequently, room-temperature polymer pellets of the unsaturated polyamide may be added to the heated dispersion medium in the extruder. The weight ratio of the dispersion medium to the polyamide may be about 60:40 to about 80:20. In terms of temperature, the extruder may be operated at about 200 rpm for about 20 minutes to about 30 minutes. Subsequently, the mixture can be discharged from the extruder onto a low-temperature surface for rapid cooling. The oil may be washed away from the unsaturated polyamide microparticles using ethyl acetate and filtered from the oil / ethyl acetate mixture. The washing procedure may include three washes with about 200 mL to about 500 mL of ethyl acetate at room temperature. The particles may be separated from the solvent by vacuum filtration onto Whatman #1, 90 mm filter paper. Subsequently, the microparticles can be air-dried overnight in an aluminum pan in a fume hood to evaporate the residual ethyl acetate. The final unsaturated polyamide particles will have a D50 of about 30 microns to about 70 microns and a span of about 0.9 to about 1.3.

[0262] Subsequently, the resulting unsaturated polyamide particles can be dispersed in methanol having a solids loading of about 15 wt% to about 30 wt%. The weight ratio of the polyamide to the initiator may be about 90:10 to about 99:1. After the particles are wetted, a dispersion of about 1 wt% to about 10 wt% of the initiator in methanol may be added to the particle slurry. Mixing may continue at ambient temperature ± about 10°C. When heating, the temperature need not be high enough to initiate cross-linking. After mixing for about 30 minutes to about 3 hours, the particles may be filtered and dried overnight in a vacuum oven.

[0263] Unsaturated polyamide particles doped with an initiator starting from Comparative Examples 4 to 6 may be used in SLS to form a consolidated structure. For example, as the CO2 laser passes through the powder bed during the sintering step of the printing process, it may slightly penetrate the top layer of the particles, resulting in a cross-linking reaction of the unsaturated bonds. These bonds may also cross-link with each other within the previously printed layer, improving the degree of curing and the final properties of the ultimately printed part. The laser speed is reduced to ensure sufficient heat penetration, and cross-linking between the printed layers can be enhanced. When a layer is scanned with a laser, the layer below the newly added layer remains partially melted and may also be partially cross-linked until the next layer of powder spreads over it. The new layer may be heated, and further, the powder activating particles of the new layer may be melted and chemically reacted with other neighboring particles.

[0264] Comparative Example 8 The preparation of unsaturated lactam monomers, 1-aza-4-cyclooctene, or 1-aza-2-ketocyclooct-5-ene can be obtained from S.R. Wilson, R.A. Sawicki, J. Org. Chem. 44 (1979) 287-291. The synthesis of the amine requires a series of reactions, first generating the oxime of 4-cycloheptene, and subsequently treating with p-toluenesulfonyl chloride and pyridine to obtain the tosylate form. The tosyl oxime can undergo a Beckmann rearrangement to obtain the lactam form, a white crystalline material.

[0265] Ring-opening metathesis polymerization can be carried out by first adding 1-aza-4-cyclooctene (125.17 g, 1 mol) and a second-generation Grubbs catalyst such as [RuCl2(p-cymene)]2 / PCy3 (0.59 g, 10 mmol) in a flask under nitrogen, and subsequently adding dry chlorobenzene (1 L). The mixture is stirred at 60 °C for 5 minutes, and then 300 mL of trimethylsilyldiazomethane (TMSD, 0.1 M in chlorobenzene, 3 × 10 -2 mmol) may be added via a syringe pump. TMSD is in-situ in the catalytic process Ris required to generate a highly reactive coordinatively unsaturated ruthenium-carbene species. The solution may be stirred at 60 °C for 24 hours. The conversion may be monitored by gas chromatography (GC). The mixture may then be cooled to ambient temperature and poured into a large amount of n-heptane. The precipitated polymer may then be dried under vacuum overnight.

[0266] Accordingly, the present invention is well adapted to attain the above-described objects and advantages, as well as those inherent therein. Since the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein, the specific embodiments and configurations disclosed above are merely exemplary. Further, it is not intended to be limited to the details of construction or design shown herein other than as described in the following claims. Accordingly, the specific exemplary embodiments disclosed above may be varied, combined, or modified, and it is evident that all such variations are contemplated within the scope and spirit of the invention. The invention disclosed herein by way of example may be practiced in the absence of any element not specifically disclosed herein and / or in the presence of any non-element disclosed herein. Compositions and methods are described in terms of the terms "comprising", "containing", or "including" various components or steps, but the compositions and methods may also "consist essentially of" or "consist of" the various components and steps. All numbers and ranges disclosed above may vary somewhat. Whenever a numerical range having a lower and upper limit is disclosed, any number and any included range within that range are specifically disclosed. In particular, all ranges of values (in the form of "from about a to about b", or equivalently "approximately a to b", or equivalently "from approximately a - b" as disclosed herein) are to be understood to set forth all numbers and ranges encompassed within the broad range of values. Also, the terms in the claims have their plain ordinary meaning unless explicitly and clearly defined by the patent owner. Additionally, when used in the claims, the indefinite articles "a" or "an" are defined herein to mean one or more of the elements they introduce. Another aspect of the present invention may be as follows. 〔1〕A method comprising: depositing particles containing an unsaturated polyamide and an initiator on a surface; and after deposition, heating at least a portion of the particles to promote consolidation thereof and crosslinking of the unsaturated polyamide, thereby forming a consolidated body containing a crosslinked polyamide. 〔2〕The method according to 〔1〕, wherein the particles have a circularity of about 0.9 to about 1.0. 〔3〕The method according to 〔1〕, wherein the weight ratio of the unsaturated polyamide to the initiator is about 90:10 to about 99:1. 〔4〕The method according to 〔1〕, wherein the particles further contain an infrared absorber. 〔5〕The method according to 〔1〕, wherein the particles have an infrared absorber mixed therewith. 〔6〕The method according to 〔1〕, wherein the particles further contain a thermoplastic polymer other than the unsaturated polyamide. 〔7〕The method according to 〔1〕, wherein the particles further contain an emulsifying stabilizer associated with the outer surface of the particles. 〔8〕The method according to 〔7〕, wherein at least some of the particles have voids containing the emulsifying stabilizer at the void / polymer interface. 〔9〕The method according to 〔7〕, wherein the emulsifying stabilizer contains nanoparticles, and the nanoparticles are embedded in the outer surface of the particles. 〔10〕A composition comprising: particles containing an unsaturated polyamide and an initiator. 〔11〕A method comprising: mixing a mixture containing an unsaturated polyamide, a dispersion medium immiscible with the unsaturated polyamide, and optionally an emulsifying stabilizer at a temperature above the melting point or softening temperature of the unsaturated polyamide and at a shear rate high enough to disperse the unsaturated polyamide in the dispersion medium; and cooling the mixture to below the melting point or softening temperature of the unsaturated polyamide to form unsaturated polyamide particles containing the unsaturated polyamide and, if present, the emulsifying stabilizer associated with the outer surface of the unsaturated polyamide particles. 〔12〕The method according to 〔11〕, further comprising dry-blending the unsaturated polyamide particles with an initiator, wherein the weight ratio of the unsaturated polyamide to the initiator is about 90:10 to about 99:1. 〔13〕The method according to 〔11〕, further comprising wet-blending the unsaturated polyamide particles with an initiator, wherein the weight ratio of the unsaturated polyamide to the initiator is about 90:10 to about 99:1. 〔14〕The method according to 〔13〕, wherein the initiator is a photoinitiator. 〔15〕The method according to 〔13〕, wherein the initiator is a thermal initiator. 〔16〕The method according to 〔11〕, wherein the mixture further comprises a thermoplastic polymer that is not the unsaturated polyamide. 〔17〕The method according to 〔11〕, wherein the mixture further comprises an infrared absorber. 〔18〕The method according to 〔11〕, wherein the emulsifying stabilizer is contained in the mixture and the emulsifying stabilizer is associated with the outer surface of the unsaturated polyamide particles. 〔19〕The method according to 〔18〕, wherein the emulsifying stabilizer comprises nanoparticles and the nanoparticles are embedded in the outer surface of the unsaturated polyamide particles. 〔20〕The method according to 〔11〕, wherein the mixture further comprises an initiator, and the weight ratio of the initiator to the unsaturated polyamide is from about 90:10 to about 99:1.

Claims

1. A step of depositing particles on a surface, the particles comprising: i) an unsaturated polyamide; ii) an initiator; and iii) an infrared absorber that absorbs electromagnetic radiation in the range of 100 nm to 1 nm, wherein an emulsifier stabilizer coating composed of nanoparticles is disposed on an outer surface of the particles, and the particles have a circularity of about 0.9 to about 1.0, and the unsaturated polyamide is i) a polycondensation reaction product of at least one amino acid monomer having an unsaturated aliphatic carbon-carbon bond, ii) a polycondensation reaction product of an amino acid monomer having an unsaturated aliphatic carbon-carbon bond and an amino acid monomer lacking an unsaturated aliphatic carbon-carbon bond, iii) a polycondensation reaction product of an amino acid monomer and a polyamine monomer, wherein at least one of the amino acid monomer and the polyamine monomer has an unsaturated aliphatic carbon-carbon bond, iv) a polycondensation reaction product of an amino acid monomer and a polyacid monomer, wherein at least one of the amino acid monomer and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, v) a polycondensation reaction product of an amino acid monomer, a polyamine monomer, and a polyacid monomer, wherein at least one of the amino acid monomer, the polyamine monomer, and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, vi) a ring-opening reaction product of a cyclic amide monomer and an amino acid monomer having an unsaturated aliphatic carbon-carbon bond, vii) a ring-opening reaction product of a cyclic amide monomer and a polyacid monomer having an unsaturated aliphatic carbon-carbon bond, viii) a ring-opening reaction product of a cyclic amide monomer and a polyamine monomer having an unsaturated aliphatic carbon-carbon bond, and ix) a ring-opening reaction product of a cyclic amide monomer, a polyamine monomer, and a polyacid monomer, wherein at least one of the polyamine monomer and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, and a step of depositing the particles, the particles comprising at least one of the above; After deposition, at least a part of the particles is heated to promote consolidation thereof and crosslinking of the unsaturated polyamide, thereby forming a consolidated body containing crosslinked polyamide. A method comprising the steps of:

2. The method according to claim 1, wherein the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99:

1.

3. The method according to claim 1, wherein the particles further comprise a thermoplastic polymer that is not the unsaturated polyamide.

4. The method according to claim 1, wherein at least some of the particles have voids containing the nanoparticles at the void / polymer interface.

5. The method according to claim 1, wherein the nanoparticles are embedded in the outer surface of the particles.

6. The method according to claim 1, wherein the particles have a D10 of from about 0.1 μm to about 125 μm, a D50 of from about 0.5 μm to about 200 μm, and a D90 of from about 3 μm to about 300 μm, with D10 < D50 < D90.

7. The method according to claim 1, wherein the unsaturated polyamide has a melting point or softening temperature of 200 °C or higher.

8. A composition comprising particles containing: i) an unsaturated polyamide; ii) an initiator; and iii) an infrared absorber that absorbs electromagnetic radiation in the range of 100 nm to 1 nm, wherein an emulsifying stabilizer coating composed of nanoparticles is disposed on the outer surface of the particles, wherein the unsaturated polyamide is i) a polycondensation reaction product of at least one amino acid monomer having an unsaturated aliphatic carbon-carbon bond; ii) a polycondensation reaction product of an amino acid monomer having an unsaturated aliphatic carbon-carbon bond and an amino acid monomer lacking an unsaturated aliphatic carbon-carbon bond; iii) a polycondensation reaction product of an amino acid monomer and a polyamine monomer, wherein at least one of the amino acid monomer and the polyamine monomer has an unsaturated aliphatic carbon-carbon bond; iv) a polycondensation reaction product of an amino acid monomer and a polyacid monomer, wherein at least one of the amino acid monomer and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond; v) a polycondensation reaction product of an amino acid monomer, a polyamine monomer, and a polyacid monomer, wherein at least one of the amino acid monomer, the polyamine monomer, and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond; vi) a ring-opening reaction product of a cyclic amide monomer and an amino acid monomer having an unsaturated aliphatic carbon-carbon bond. vii) The ring-opening reaction product of a cyclic amide monomer and a polyacid monomer having an unsaturated aliphatic carbon-carbon bond, viii) The ring-opening reaction product of a cyclic amide monomer and a polyamine monomer having an unsaturated aliphatic carbon-carbon bond, and ix) The ring-opening reaction product of a cyclic amide monomer, a polyamine monomer, and a polyacid monomer, wherein at least one of the polyamine monomer and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, A composition comprising at least one of.

9. The composition according to claim 8, wherein the particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, and D10 < D50 < D90.

10. The composition according to claim 8, wherein the particles have a circularity of about 0.9 to about 1.

0.

11. i) An unsaturated polyamide, ii) A dispersion medium immiscible with the unsaturated polyamide, iii) An infrared absorber that absorbs electromagnetic radiation of 100 nm to 1 nm, iv) An emulsifying stabilizer composed of nanoparticles dispersible in the dispersion medium, A step of shearing a mixture containing at a temperature exceeding the melting point or softening temperature of the unsaturated polyamide and at a shear rate high enough to disperse the unsaturated polyamide as droplets in the dispersion medium and to place the nanoparticles at the interface between the droplets and the carrier fluid, Optionally, at least a part of the infrared absorber contains the nanoparticles, The unsaturated polyamide is i) The polycondensation reaction product of at least one amino acid monomer having an unsaturated aliphatic carbon-carbon bond, ii) The polycondensation reaction product of an amino acid monomer having an unsaturated aliphatic carbon-carbon bond and an amino acid monomer lacking an unsaturated aliphatic carbon-carbon bond, iii) The polycondensation reaction product of an amino acid monomer and a polyamine monomer, wherein at least one of the amino acid monomer and the polyamine monomer has an unsaturated aliphatic carbon-carbon bond, iv) The polycondensation reaction product of an amino acid monomer and a polyacid monomer, wherein at least one of the amino acid monomer and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, v) A polycondensation reaction product of an amino acid monomer, a polyamine monomer, and a polyacid monomer, wherein at least one of the amino acid monomer, the polyamine monomer, and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, the polycondensation reaction product. vi) A ring-opening reaction product of a cyclic amide monomer and an amino acid monomer having an unsaturated aliphatic carbon-carbon bond. vii) A ring-opening reaction product of a cyclic amide monomer and a polyacid monomer having an unsaturated aliphatic carbon-carbon bond. viii) A ring-opening reaction product of a cyclic amide monomer and a polyamine monomer having an unsaturated aliphatic carbon-carbon bond, and ix) A ring-opening reaction product of a cyclic amide monomer, a polyamine monomer, and a polyacid monomer, wherein at least one of the polyamine monomer and the polyacid monomer has an unsaturated aliphatic carbon-carbon bond, the ring-opening reaction product. including at least one of the steps of shearing; cooling the mixture to below the melting point or softening temperature of the unsaturated polyamide to form particles comprising the unsaturated polyamide and the infrared absorber, a forming step in which an emulsifier stabilizer coating composed of nanoparticles is disposed on the outer surface of the particles. A method comprising:

12. The method according to claim 11, further comprising dry blending the particles with an initiator, wherein the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99:

1.

13. The method according to claim 11, further comprising wet blending the particles with an initiator, wherein the weight ratio of the unsaturated polyamide to the initiator is from about 90:10 to about 99:

1.

14. The method according to claim 13, wherein the initiator is a photoinitiator.

15. The method according to claim 13, wherein the initiator is a thermal initiator.

16. The method according to claim 11, wherein the mixture further comprises a thermoplastic polymer other than the unsaturated polyamide.

17. The method according to claim 11, wherein the nanoparticles are embedded in the outer surface of the particles.

18. The method according to claim 11, wherein the mixture further comprises an initiator, and the weight ratio of the initiator to the unsaturated polyamide is from about 90:10 to about 99:

1.

19. The method according to claim 11, wherein the particles have a D10 of from about 0.1 μm to about 125 μm, a D50 of from about 0.5 μm to about 200 μm, and a D90 of from about 3 μm to about 300 μm, with D10 < D50 < D90.

20. The method according to claim 11, wherein the particles have a circularity of from about 0.9 to about 1.0.

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