Ceramic inkjet ink composition for printing on dental restorations

Abstract

A method for manufacturing a ceramic inkjet ink for printing on a dental material substrate includes processing a solid particulate component to a particle size of 0.8 pm to 1 pm at a particle size distribution of D98, and adding an effective amount of an additive to the solid particulate component to produce an ink capable of being dispensed from an inkjet print head onto a surface of a three-dimensional dental material substrate having an irregular shape and uneven surface while the three-dimensional dental material substrate is simultaneously translated and rotated beneath the inkjet print head.

Description

[0001] Priority is claimed under 35 USC §119.

[0002] This patent application claims priority to provisional application number 63 / 627,670, filed on January 31, 2024, entitled “SYSTEM AND METHOD FORGLAZING DENTAL RESTORATIONS WITH CERAMIC INK VIA INKJET PRINTER”, which is assigned to the assignee of this application and is hereby expressly incorporated herein by reference. background Technical Field

[0003] Various embodiments involve ceramic inkjet inks and enamel inkjet compositions for coloring dental material substrates, which mimic the coloring and translucency of human teeth. Background Technology

[0004] Conventional inkjet printing of ceramic inks onto ceramic products faces numerous technical limitations, including stability issues and limited color intensity and gamut. While improvements to the technology are still being sought, greater technical and commercial success has been achieved through solvent-based ceramic inkjet ink compositions containing dispersions of pigments suitable for ceramic decoration. Because of the use of non-contact inkjet printing, there are fewer requirements regarding the surface shape of the printing media. However, the requirements for ceramic inkjet ink compositions can be very challenging due to the small size of the printhead nozzles on inkjet printers and the high solids loading of ceramic inkjet inks.

[0005] When the pigment particle size is small, it can be more difficult to obtain color. In recent years, a great deal of effort has been spent on obtaining inkjet compositions that can be applied using conventional inkjet equipment to print on a variety of substrates without interfering with the color development of ceramic inkjet inks.

[0006] The main problem with ceramic inkjet inks is that they often produce poor print quality when printed on unfired glazes. This poor print quality manifests itself as blurry, variable color intensity, uneven gloss across the substrate, cracking, and bleeding. These print quality problems (which become apparent after the firing of the glaze and ink combination) have been found to be related to poor ink absorption into the unfired glaze. Inks must also meet several criteria. First, they must possess the correct rheological and other properties, allowing them to be easily ejected or dispensed from the nozzles of the inkjet printhead. Attempts to print ceramics via inkjet processes frequently fail due to the significant tendency for particularly heavy and coarse color powders to form deposits, which are produced when the solid components of the ink settle from aqueous or alcoholic suspensions, leading to nozzle clogging in inkjet printing equipment.

[0007] Another problem with formulating ceramic inkjet inks is that the conventional glazes used to formulate these inks consist of a mixture of raw materials made of metal oxides, which react together in appropriate proportions during firing cycles to achieve a homogeneous fusion of the metal oxides. This formulation can contain excessive amounts of fine solid metal oxide particles and pigment particles, leading to instability and particle aggregation.

[0008] Therefore, there has been little success in addressing the many requirements of ceramic inkjet inks to enable them to meet all the physicochemical properties required for inkjet printing (e.g., particle size, particle size distribution, viscosity, density, surface tension, firing heat resistance, etc.). Nor has any ceramic ink been found capable of printing in a three-dimensional plane on uneven, rough surfaces of a substrate (with very small surface areas) during inkjet printing, while the substrate is simultaneously translated and / or rotated, and capable of maintaining its desired color characteristics after the substrate surface has been fired. Summary of the Invention

[0009] This summary is provided to introduce the selection of a simplified form of concept, which will be further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0010] Various embodiments provide enamel and ceramic inkjet ink compositions that can be used to alter the physical and aesthetic properties of the surface of dental material substrates, and thus provide functional coatings or enamel and ceramic inkjet ink compositions. The physical and aesthetic properties of the substrate can be altered or modified by the composition, and can affect various properties of the substrate after firing, including gloss, contrast gloss (luster), specular reflectivity (metallic or glassy appearance), embossing, and smoothness.

[0011] One embodiment relates to a ceramic inkjet ink for dental material substrates. The ink includes ceramic pigments. The ceramic pigments include metal oxide solid particles having a submicron particle size of less than 1 micrometer in a particle size distribution of D98 to D10, and inorganic pigment solid particles having a submicron particle size of less than 1 micrometer in a particle size distribution of D98 to D10. The ink also includes a solvent and a dispersant. The ink has a solid particle loading of about 10% to about 50% by weight, wherein the ink exhibits good jetting ability when uniformly jetted onto the surface of the dental material substrate by an inkjet printer, and wherein the ink is capable of fusing to the surface of the dental material substrate by firing at elevated temperatures and retaining its aesthetic color properties after firing.

[0012] Another embodiment relates to a concentrated enamel paste composition for use as a dental material substrate. The composition comprises enamel powder including submicron metal oxide solid particles having a particle size of less than 1 micrometer within a particle size distribution ranging from D98 to D10. The composition also contains a solvent, a dispersant, and additives. The concentrated enamel paste composition has a solid particle loading ranging from 10% to 70% by weight.

[0013] Another embodiment relates to a method for manufacturing digital ceramic inkjet inks for dental material substrates. The method includes wet milling concentrated enamel powder in a solvent in the presence of a first dispersant and a first anti-settling agent to produce a concentrated enamel paste having solid enamel powder particles with a particle size of 0.8 μm to 1 μm under a D98 particle size distribution. The method also includes wet milling colored dye powder in a solvent in the presence of a dispersant and an anti-settling agent to produce a concentrated dye enamel paste having solid particles with a particle size of 0.8 μm to 1 μm under a D98 particle size distribution. The method further includes mixing concentrated enamel paste and concentrated dye enamel paste in a mixer to produce a dye-enamel mixture, adding a diluted solution of a mixture containing solvents and additives to the dye-enamel mixture to produce a precursor colored ceramic inkjet composition having a solids loading content of about 20% to about 60% by weight based on the total weight of the colored ceramic inkjet ink composition and desired inkjet characteristics, and filtering the precursor colored ceramic inkjet composition first through a 5-micron pore size filter and then through a 2-micron pore size filter to remove any excessively large solid particles, thereby obtaining a digital ceramic inkjet ink with a viscosity of 12 mPa·s to 25 mPa·s at the jetting temperature and jetting conditions.

[0014] Another embodiment relates to a method for manufacturing ceramic inkjet ink for printing on a dental material substrate, the method comprising processing a solid particulate component to a particle size of 0.8 μm to 1 μm under a particle size distribution of D98, and adding an effective amount of additive to the solid particulate component to produce ink capable of being dispensed from an inkjet printhead onto the surface of a three-dimensional dental material substrate having an irregular shape and uneven surface, the three-dimensional dental material substrate being simultaneously translated and rotated below the inkjet printhead. Detailed Implementation

[0015] Preferred embodiments of the invention will now be described in detail. Although the invention will be described in conjunction with preferred embodiments, it should be understood that they are not intended to limit the invention to these embodiments. Rather, the invention is intended to cover substitutions, modifications, and equivalents that may be included within the spirit and scope of the invention as defined by the claims. Furthermore, numerous specific details are set forth in the detailed description of the invention to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the invention.

[0016] Definitions

[0017] Throughout the specification and claims, terms may have subtle meanings beyond those explicitly stated, implied or suggested in the context. Similarly, the phrase "in one embodiment" as used herein does not necessarily refer to the same embodiment, and the phrase "in another embodiment" as used herein does not necessarily refer to different embodiments. For example, the claimed subject matter is intended to include combinations of all or some of the example embodiments.

[0018] The "coefficient of thermal expansion" (or CTE) refers to the physical or material properties required of the various embodiments of the present invention and the dental material substrate itself after each having undergone firing. CTE indicates the curvature, bending, notches, cracks, etc., of the composition or dental material substrate, and describes how the composition or substrate expands or contracts, or the rate of expansion or contraction, when subjected to temperature changes. The CTE of enamel inkjet compositions and ceramic inkjet ink compositions should be compatible with the CTE of the dental material substrate below to prevent cracking, fissures, or deformation during firing and cooling cycles. As used in the dental industry, CTE typically refers to the CTE of Cerabian ZR (CZR) and is customized to match the CTE of a zirconia frame, which typically has a CTE of 10.0 x 10⁻⁶. -6 / ℃ to 10.5x10 -6The CTE range is within the range of / ℃, depending on the type of zirconia used. Mismatched CTE values ​​between the enamel inkjet composition, ceramic inkjet ink composition, and the underlying dental material substrate can lead to thermal stress and aesthetic or structural failure. For example, the CTE of the ceramic inkjet ink composition should match the CTE of the dental crown material made of zirconia. A wide CTE range is needed to accommodate the variability of the composition and the dental material substrate. As a non-limiting example, the CTE of the enamel inkjet composition, ceramic inkjet ink composition, and the underlying dental material substrate according to various embodiments can be 65 × 10⁻⁶ °C. -7 / ℃ to 75×10 -7 Within the range of / ℃, preferably within 50×10 -7 / ℃ to 80×10 -7 Within the range of / ℃, and more preferably within 9.0×10 -6 / ℃ to 11.0×10 -6 Within the range of / ℃.

[0019] "Surface tension" refers to the physicochemical characteristics that control the liquid behavior at the fluid interface of ceramic inkjet ink compositions and enamel inkjet compositions according to various embodiments. More specifically, it affects the ejection of the composition from the nozzle of a printhead using an inkjet printer, as well as the interaction of the composition with dental material substrates. Surface tension also affects droplet formation, ejection stability, and droplet-dental material substrate interaction. The surface tension of ceramic inkjet ink compositions and enamel inkjet compositions according to various embodiments is tailored to specific printhead designs, inkjet composition, and dental material substrate requirements, and can be further tuned by including additives (such as surfactants, polymers, or other additives) to prevent inkjet composition diffusion and achieve optimal printhead performance. As a non-limiting example, the surface tension of ceramic inkjet ink compositions and enamel inkjet compositions according to various embodiments can be in the range of 20 mN / m to 40 mN / m, and preferably in the range of 25 mN / m to 30 mN / m.

[0020] "Sedimentation" refers to the physical property of the gravitational settling of solid particles in the enamel inkjet composition and ceramic inkjet ink composition of the present invention over a period of time under standard storage conditions. This phenomenon affects the stability of the enamel inkjet and ceramic inkjet ink compositions and nozzle clogging of the printhead. Sedimentation is influenced by factors including particle size, density, media viscosity, and the interactions between particles in the composition. This sedimentation can be determined by optical analysis of the liquid dispersion of the composition and is expressed as a weight percentage of the enamel inkjet and ceramic inkjet ink composition. The sedimentation rate of inkjet inks is generally designed to be extremely low or negligible during the shelf life of the ink, as it can lead to serious printhead performance and print quality problems. As a non-limiting example, the sedimentation rate of the enamel inkjet and ceramic inkjet ink compositions according to various embodiments can be less than 0.1% by weight, and preferably from 0.013% by weight to 0.06% by weight.

[0021] "Ejection temperature" refers to the temperature of the enamel inkjet and ceramic inkjet ink composition at the printhead. As a non-limiting example, the ejection temperature according to various embodiments can be in the range of 30°C to 60°C, and preferably 35°C to 45°C.

[0022] "Particle size" refers to the average particle size of the particles in an enamel and ceramic inkjet ink composition, and can be designed to be very small (e.g., in the submicron or nanometer range and meeting the generally accepted definition of nanoparticles) to ensure smooth jetting and prevent printhead nozzle clogging. Submicron particle size can be achieved by grinding the enamel and ceramic inkjet ink composition to have a particle size sufficiently small to prevent sedimentation and ensure a stable suspension of particles passing through the printhead nozzles; this particle size typically has a diameter of 15 μm to 50 μm. As a non-limiting example, the particle size of the enamel and ceramic inkjet ink compositions according to various embodiments can be submicron in nature and range from 3 micrometers to less than 1 micrometer.

[0023] "Particle size distribution" refers to the median particle size (i.e., equivalent sphere diameter) of the volumetric distribution. For example, the term "D98" refers to the 98th percentile of the volumetric median particle size (i.e., the diameter found in 98% by volume of the particle population that is smaller than this diameter). Therefore, a particle size of 0.80 μm at a D50 particle size distribution would mean the median of the particle size distribution in which 50% by volume of the control sample would have an equivalent diameter smaller than 0.80 μm.

[0024] "Viscosity" refers to the shear rate of enamel and ceramic inkjet ink compositions, which can be measured at shear rates from 100 (L / s) to 1000 (L / s) using a rotational viscometer at the jetting temperature or at frequencies from 50 Hz to 500 Hz using a high-frequency rheometer. The viscosity of the composition should be low enough to allow it to be printed by an inkjet printer (at room temperature). As a non-limiting example, the viscosity of the composition is in the range of 3 mPa·s to 200 mPa·s at shear rates in the range of 100 L / s to 1000 L / s.

[0025] The pH and conductivity of the ceramic inkjet ink composition of the present invention were measured at 25°C using an Oakton 510 series pH / conductivity meter.

[0026] "Good jetting capability" refers to sufficient droplet formation for ink compositions used in enamel and ceramic inkjet printing when ejected from the printhead of an inkjet printer at different droplet volumes. There should be no satellite droplets or droplet breakage that could be detrimental to the quality of the printed image; this is typically verified through inkjet testing on a droplet observer.

[0027] "Good inkjet print quality" means that the image meets the end-use application and is usually verified using a series of tests, such as line straightness, wicking, feathering, dot gain, and hue.

[0028] "Storage stability" refers to the number of days, weeks, or months that a ceramic inkjet ink composition can be stored without any significant settling or degradation (which may result in poor performance).

[0029] "Open time" refers to the time the printhead can remain open (and therefore remain open) before all nozzles are fully operational when printing resumes. A normal open time is at least one hour.

[0030] "Blurry" refers to a printed design with intermediate ink discharge, resulting from insufficient ink absorption into the enamel. This is evident in the halftone printing areas of the design, where adjacent ink droplets coalesce at the surface, creating a slightly stained appearance, as if the image were printed with large ink droplets at very low resolution.

[0031] "Bleeding" or "bleed" refers to solid areas in printed designs where unabsorbed ink flows through a damp enamel, causing image edge distortion and mixing with other areas of the print, resulting in color halos and poor print resolution.

[0032] "Resolvability" refers to the time taken to resolvate ceramic inkjet ink compositions that have dried out in digital printheads due to poor maintenance or downtime. It is expected that the ceramic inkjet ink composition will resolv within less than 10 minutes when using standard flushing, cleaning, or maintenance fluids, thus enabling the restoration of any clogged nozzles in the printhead. Data measured on samples taken from metal substrates clearly demonstrate that by including small amounts of metal or metal oxides in the ceramic inkjet ink composition, color shift can be significantly reduced to levels acceptable in the inkjet printing industry, i.e., ΔE less than 3.0.

[0033] "Coverage" refers to the physical properties related to the viscosity and melt surface tension of enamel and ceramic inkjet ink compositions, serving as a characteristic basis for achieving continuous coverage of the composition on the surface of dental material substrates. As a non-limiting example, the coverage of enamel and ceramic inkjet ink compositions after firing can be less than 200 g / m². 2 Preferably below 150g / m 2 And more preferably below 100g / m 2 The sintering and softening temperatures during firing can be in the range of 700℃ to 1300℃.

[0034] Ceramic pigment

[0035] According to various embodiments, enamel inkjet compositions can be applied directly to the surface of dental material substrates (e.g., dental crowns). Enamel inkjet compositions can also be applied to wet and dry ceramic inkjet ink compositions or ceramic staining inks. The interaction between the dental material substrate, the enamel inkjet composition, and the ceramic inkjet ink composition is crucial to the final result of inkjet printing on the dental substrate material.

[0036] One of the key challenges in formulating enamel inkjet compositions with high solids loading is achieving good particle dispersion and preventing sedimentation and agglomeration during storage, while still maintaining a very low viscosity of the composition. Further challenges involve preventing clogging of the inkjet printhead channels and nozzles. From an ink ejection perspective, the challenge is reliably ejecting small, satellite-free droplet sizes of ink at high frequencies. Given the environment in which inkjet printers will operate, this enamel inkjet composition also requires improved nozzle open time (i.e., the ability to eject the composition for extended periods without nozzle failure). Achieving this requires careful consideration and a delicate balance when formulating enamel inkjet compositions and any ceramic inkjet inks formulated from them.

[0037] Therefore, various embodiments involve enamel-based and ceramic-based inkjet ink compositions with entirely different properties, which enable them to be inkjet-applied to dental material substrates without clogging printheads or nozzles. Consequently, they preferably possess suitable physical properties, such as viscosity in the range of 5 mPa·s to 50 mPa·s, surface tension of about 20 mN·m to 40 mN·m, and density of about 0.8 g / ml to about 1.5 g / ml. Advantageously, the compositions according to the various embodiments preferably exhibit extremely low or no volatility and are stable with materials used in the manufacture of inkjet printing systems (e.g., printheads, nozzles, delivery lines, etc.).

[0038] One object of the present invention is to develop a ceramic inkjet ink composition that meets the requirements of ceramic systems. For example, once applied to the surface of a substrate after firing, the ceramic inkjet ink composition should be able to produce the desired surface effects (i.e., the desired physical surface changes). The ceramic inkjet ink composition should also be able to interact with the glazed substrate surface to become part of that glazed substrate surface. The ceramic inkjet ink composition should also contain a sufficiently high solids loading to allow for reasonable productivity and, despite the high solids loading, still allow for sufficient resolution.

[0039] Various implementation schemes involve developing inkjet formulations using additives such as rheology modifiers, viscosity modifiers, and surface tension modifiers, in order to formulate enamel and inkjet ink compositions in a manner in which they can be readily incorporated into the base fluid during the dilution stage to improve or modulate their physicochemical properties and substrate interaction behavior.

[0040] Various implementations may involve developing formulation routes for glaze inkjet and ceramic inkjet ink compositions, thereby employing a short list of additives (e.g., dispersants, rheology modifiers, binders, humectants, surfactants, and other additives) that are fully compatible with the components used to formulate the glaze inkjet and ceramic inkjet ink compositions, and wherein the additives can be readily added to, for example, concentrated pastes of glazes or coloring dyes to appropriately fine-tune the inkjet composition at the end-user location.

[0041] Various implementations may involve developing enamel powders with particles that can be ground together with intermediates to produce submicron particles suspended in a solvent, which ensure complete material compatibility of the enamel inkjet composition with additives (e.g., dispersants, rheology modifiers, binders, humectants, surfactants, and other additives) in enamel inkjet and ceramic inkjet ink compositions.

[0042] Various implementation schemes may involve developing systems for optimizing the complex rheological properties of glaze inkjet and ceramic inkjet ink compositions to match the specific requirements of selected inkjet printheads with custom waveforms.

[0043] Various implementation schemes may involve the development and formulation of key diluent solutions, additives, rheology modifiers and intermediates, which enable the formulation of enamel inkjet and ceramic inkjet ink compositions in a manner that allows them to be readily incorporated into the base fluid during the dilution stage to improve rheological and substrate interaction behavior.

[0044] Ceramic pigment

[0045] Ceramic pigments used to generate ceramic inkjet ink compositions according to various embodiments can be represented as metal oxides and inorganic pigments. Other types of pigments may also be used, including: organometallic pigments, complexes, micronized pigments, colloidal metals, nanopigments, and reactive, unique precursors for in-situ pigment synthesis, such as polyols and sol-gel synthesis. The Classification and Chemical Descriptions of the Complex Inorganic Color Pigments, Fourth Edition (2010), contains a list of ceramic pigments.

[0046] Examples of suitable metal oxides may include oxides of Si, Fe, Co, Sn, Zn, Pr, Ni, or Cr, silicate, or zirconate compounds. In particular, suitable metal oxides that can be used to prepare the enamel-forming materials of the present invention may include, but are not limited to, silica (SiO2), boron oxide (B2O3), La2O, B2C3, and oxides of Al (Al2O3), R2O (generally referring to the group of basic oxides: Li2O, Na2O, K2O), B (BaO), ZnO, ZrO2, SnO2, TiO2, P2O5, zinc borate, RO (generally referring to the group of oxides: MgO, CaO, SrO, BaO, Mg (MgO)), or mixtures thereof. The number of basic oxides that can be used to prepare enamel-forming materials is virtually unlimited. However, most are based on silicates (Si), zinc oxide (ZnO), and boric acid (H3BO3), with varying concentrations of alkali, copper, and lime. SiO2 is a preferred oxide because it has the ability to produce insoluble, glassy materials when combined with other oxides. The SiO2-based oxides are present in proportions between 20% and 49% by weight; the Al2O3-based oxides are present in proportions between 0.01% and 1% by weight; and combinations of metal oxides are also included, such as combinations of LiO2+Na2O+K2O; combinations of MgO+CaO+SrO+BaO; combinations of B2O3+LiO2+ZnO; combinations of B2O3+LiO2; combinations of Na2O+K2O+TiO2; and other metal oxides known to those skilled in the art of the ceramics industry; wherein the weight percentages are relative to the total weight of the metal oxides in the glaze inkjet composition.

[0047] Based on the weight of the enamel inkjet composition, the metal oxide used in the enamel inkjet composition according to various embodiments can be in the range of 0.1% to 10% by weight, preferably 2% to 5% by weight, and more preferably 0.1% to 2% by weight.

[0048] The inorganic pigments referred to in this article as ceramic pigments may refer to pigments that are or at least partially metal oxides, are heat-resistant, and do not burn off completely during the firing process once the ink is applied to the surface of the substrate, wherein the inorganic pigment is deposited on the surface of the substrate, and wherein most of its optical properties (e.g., color, optical density, gloss, etc.) are retained after firing.

[0049] Examples of suitable inorganic pigments include, but are not limited to, silica, sand, feldspar, alumina, clay, zirconium silicate, zinc oxide, zinc cadmium sulfide, dolomite, borate, calcite, kaolinite, silica quartz, barium carbonate, wollastonite, tin oxide, nepheline, bismuth oxide, calcium staborite, calcium carbonate, cerium dioxide, cobalt oxide, chromium copper black spinel, cobalt chromite, cobalt titanium spinel, copper oxide, iron oxide, iron oxide red, aluminum phosphate, iron carbonate, manganese oxide, sodium fluoride, chromium oxide, strontium carbonate, lithium carbonate, blue-green spinel, cobalt aluminum blue spinel, nickel antimony titanium gold rutile, titanium dioxide rutile and anatase, cadmium sulfide, cadmium suloslenide, spodumene, talc, magnesium oxide, manganese ferrite, cristobalite, rutile, bismuth anatase, albite, vanadium oxide, ammonium pentavanadate, and mixtures thereof. Examples of ceramic pigments and their colors prepared by in-situ synthesis of suitable single precursor polyols include, but are not limited to, CoFe2O4 (black), CoAl2O4 (blue), Ti(Cr, Sb)O2 (yellow), Au (magenta), and Cu (magenta), as well as mixtures thereof.

[0050] Examples of other suitable inorganic pigments that can also be used to prepare ceramic inkjet ink compositions according to various embodiments include, but are not limited to, stibnite (Pb₂Sb₂O₇, yellow), olivine (Co₂SiO₄, blue), spinel (Co, Ni, Fe, Cr, Mn)₃O₄ and CoAl₂O₄, blue and black), cassiterite ((Sn, Cr)O₂, pink), corundum ((Cr, Al)₂O₃, green), and perovskite (Ca₃Cr₂Si₃O₄). 12 The following minerals are listed: green, Malayanite (Ca(Sn, Cr)SiO5, deep purplish-red), cadmium sulfide (Cd(S, Se), orange-red), rutile ((Ti, Cr, Sb, W)O2, orange and tobacco-colored), zircon ((Zr, Pr)SiO4, (Zr,V)(Si, V)O4, Fe2O3ZrSiO4, yellow, turquoise and red respectively), cristobalite ((Zr, V)O2, yellow), cerium terreum ((Ce, Pr)O2, red), perovskite (Y(Al, Cr)O2, red), and copper-silica calcium silicate (CaCuSi4O). 10 (blue), azurite (blue), copper-wollastonite ([Ca,Cu]3Si3O9, green), and mixtures thereof.

[0051] Inorganic pigment particles should be small enough (e.g., micronized or nanoparticles) to allow ceramic inkjet ink compositions formulated with colorant particles to flow freely through the nozzles of an inkjet printing apparatus. To achieve this, the particles can be milled (e.g., wet milling) to have an average submicron particle size of less than 1 μm in a particle size distribution ranging from D10 to D98, and can be tuned by introducing additives that can adjust or modify the composition's resolubility, good jetting and settling rates, coefficient of expansion, surface tension, storage stability, transparency, and color gamut.

[0052] Based on the weight of the ceramic inkjet ink composition, the inorganic pigment, according to various embodiments, can be used in the range of 0.1% to 10% by weight, preferably 0.01% to 5% by weight, and more preferably 0.1% to 2% by weight.

[0053] Dispersant

[0054] To incorporate ceramic pigments into ceramic inkjet ink compositions, the ceramic pigments can be manufactured as a concentrate in water or a solvent and stored stably. This is typically achieved by dispersing the pigment material in water or a solvent using a dispersant.

[0055] Examples of suitable dispersants include, but are not limited to, polymer dispersion resins such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, acrylic acid-acrylonitrile copolymers, vinyl acetate-acrylate copolymers, acrylic acid-acrylate copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylate copolymers, styrene-α-methylstyrene-acrylic acid copolymers, styrene-α-methylstyrene-acrylate-acrylate copolymers, styrene-maleic acid copolymers, styrene-maleic anhydride copolymers, vinylnaphthalene-acrylic acid copolymers, vinylnaphthalene-maleic acid copolymers, vinyl acetate-maleic ester copolymers, vinyl acetate-crotonic acid copolymers, and vinyl acetate-acrylic acid copolymers, as well as their salts. Examples of suitable copolymer dispersion resins include, but are not limited to, any form of random copolymers, block copolymers, alternating copolymers, and graft copolymers. Examples of suitable dispersible resin salts include, but are not limited to, salts of sodium hydroxide, potassium hydroxide, and basic compounds such as ammonia, ethylamine, diethanolamine, triethanolamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, diethanolamine, triethanolamine, triisopropanolamine, dimethylethanolamine, aminomethylpropanol, and morpholine.

[0056] Examples of commercially available dispersants include, but are not limited to, Disper BYK 111, 180, 182, 184, 190, 191, 192, 194, 2010, 2015, and 2155 (all from Altana); Additol XW 6565, XW 6575, XW 330, and XL6577 (from Allnex); Efka PU 4009, 4010, and Fa4564; Joncryl 67, 678, 8500, 586, 611, 680, 682, 683, and 69 (from BASF); and Solsperse. J945, J955, J980, J981, J944, J950 (purchased from Lubrizol); Anti-terra-250, E-sperse (purchased from Ethox); Fluijet (purchased from Lamberti), PVP K-15, K-30, K-60, and Tego 7502 and 752W (purchased from Evonik), etc. Dispersants according to various embodiments can be used alone or in combination, and can range from 1% to 20% by weight based on the weight of the enamel inkjet and ceramic inkjet ink composition.

[0057] Solvent

[0058] Enamelled and ceramic inkjet ink compositions according to various embodiments may include an organic solvent and water as a co-solvent. The organic solvent used in the various embodiments may include hydrophilic, hydrophobic, polar, nonpolar, and aqueous solvents. The use of a solvent helps reduce the evaporation rate of any aqueous component and further prevents the composition from drying in the nozzles of the inkjet printhead, thereby preventing nozzle clogging. The solvent also provides a secondary function as a wetting aid, thereby allowing the inkjet droplets to spread on the substrate. Finally, the solvent enhances the solubility of the components of the composition and promotes the penetration of the composition into the dental material substrate. Using water as a co-solvent ensures that the composition is not highly flammable or volatile and should not be water containing any ionic impurities, such as ion-exchanged or distilled water.

[0059] Examples of suitable organic solvents include, but are not limited to, C 12 To C 40 Hydrocarbons, traded under the commercial brands D40, D80, and D120 (purchased from Exxsol), including dearomatized hydrocarbons of isoalkanes, alkanes, and cycloalkanes, dearomatized aliphatic hydrocarbons, and C 12 To C 40 Aliphatic solvents, C 12 To C 40Straight-chain alkanes, such as alkanes, ester solvents; diols, such as methyl glycol, ethyl glycol, butyl glycol, alkylene glycols, alkylene glycol ethers or ether acetates, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol butyl ether, diethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether, dipropylene glycol ethyl ether, dipropylene glycol methyl ether, ethylene glycol butyl ether, ethylene glycol ethyl ether. Ethylene glycol isopropyl ether, ethylene glycol methyl ether, ethylene glycol propyl ether, glyceryl carbonate, N-methyl-2-pyrrolidone, glycerol, propylene glycol, glycol ethers such as propylene glycol ethyl ether, propylene glycol ethyl ether acetate, propylene glycol methyl ether, propylene glycol n-propyl ether, triethylene glycol butyl ether, triethylene glycol methyl ether, tripropylene glycol, tripropylene glycol methyl ether; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, polyols, ethoxypropanol , methoxybutanol, ethylene glycol, propylene glycol, dipropylene glycol, glycerol and polyethylene glycol, etc.), ketones and ketols such as acetone, diacetone alcohol, diacetone propanol and methyl ethyl ketone, methyl butyl ketone, cyclohexanone; ethers such as methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methoxypropyl acetate, ethyl-3-ethoxy-propanol, tetrahydrofuran, dioxane and alkyl ethers, ethers of polyols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, di(ethylene glycol) monomethyl ether); nitrogen-containing solvents such as 2-pyrrolidone and N-methyl-2-pyrrolidone; sulfur-containing solvents such as 2,2'-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone and sulfolane, and sugars and their derivatives such as glucose, ethylene oxide adducts of glycerol and ethylene oxide adducts of diglycerol propylene glycol and / or dipropylene glycol, N-methylpyrrolidone and urea, etc.

[0060] Organic solvents can be used alone or in combination, and when used alone, the organic solvent is used in an amount ranging from 50% to 80% by weight, based on the weight of the enamel or ceramic inkjet ink composition. Water-based solvents (i.e., organic solvents having water as a co-solvent) are used in an amount ranging from 25% to 60% by weight, based on the weight of the enamel or ceramic inkjet ink composition.

[0061] Binder

[0062] Ceramic inkjet ink compositions and glaze inkjet compositions according to various embodiments include, but are not limited to, polymeric binders compatible with other components of the composition. The binder imparts many desired properties, including but not limited to substrate adhesion, stability, smear resistance, viscosity, surface tension, coating penetration, optical density, color depth, adhesion, gloss resistance, resolubility, and crusting resistance. Examples of suitable adhesives and commercially available adhesives include, but are not limited to, polyurethane dispersions, polyacrylic and polyurethane dispersion-acrylic copolymers, hydroxypropyl cellulose, PVP series; Lubrijet N240, Carboset 560, PrintRite DP375 and XPD-3276 (purchased from Lubrizol); TegoVariplus DS50, Tego Silkopur 8081 (purchased from Evonik); Joncryl 90, Joncryl 8055, Joncryl8050-E, Joncryl ECO 2189-E, Joncryl 8211, Joncryl ECO 2177-E (purchased from BASF); UC-84 from Albertingk Boley; Daotan TW 6450, Daotan 6490, Reshydrol SF 8000, Reshydrol SF 8010, Reshydrol 8011, Daotan TW 7000, Daotan TW 6425, Daotan VTW6460, Daotan 7225 (purchased from Allnex); Optiflo L 1400, Optiflo T 1000, and Optiflo T 1010 (purchased from Altana); Phenoxy PKHW 34, Phenoxy PKHW 35, and Phenoxy PKHW 38 (purchased from [unclear]); Azelis, Aquazol 5, and Aquazol 50 (purchased from Chempoint); Neoclil BT21, Neoclil XK-12, Neorez R-2005, Neorez R-4000, Neoclil A-1127, Neoclil A-1125, Neopac E-200, Neoclil A-1131, and Neoclil D-2101 from DSM; EPS 546 and Dyflex LP 9419 (purchased from EPS Materials); Hauthane L-2892, Hauthane L-2897, Hauthane HD-4670, and Hauthane L-2183 (purchased from CLHauthaway and Sons Inc.).Esajet PU77, Esajet 4518, Esajet AC20, Esajet 200, Esajet4518, Esajet PU 931, Esajet 5913 (purchased from Lamberti); Takelac WS-4022 and Takelac WS-5000 (purchased from Mitsui Chemicals); and Syntran 3101 (purchased from Zschimmer and Schwarz).

[0063] The adhesive can be used alone or in combination, and can range from 1% to 10% by weight, depending on the weight of the enamel inkjet and ceramic inkjet ink composition.

[0064] Surfactant

[0065] Surfactants or wetting agents are used in the pigment dispersions of the inkjet inks of the present invention to reduce the interfacial tension that causes them to spread on solid surfaces, and in various embodiments may include anionic, nonionic, and cationic surfactants. Examples of suitable anionic surfactants include, but are not limited to, alkane sulfonates, α-olefin sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, acylmethyl taurate, dialkyl sulfosuccinate, alkyl sulfates, sulfurized olefins, polyoxyethylene alkyl ether phosphates, polycarboxylic acids, and monoglycerides of phosphate; amphoteric surfactants, such as alkylpyridinium salts; and nonionic surfactants, such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamides, glyceryl alkyl esters, and dehydrated sorbitol alkyl esters. Suitable nonionic surfactants include, but are not limited to, commercially available nonionic surfactants such as BYK 345 and 305.

[0066] Examples of suitable cationic surfactants include, but are not limited to, commercially available cationic surfactants such as BYK 300, 306, 345, 3481 and BYK Dynwet 810.

[0067] Examples of commercially available surfactants include, but are not limited to, PLURONIC. ® Series, TETRONIC ® Series, ICONOL ® The series, as well as the EFKA 1000, 4000, 5000 and 6000 series (purchased from BASF Corporation, Parsippany, NJ); ARQUAD ® Series (purchased from Akzo Chemical Inc., Chicago, Ill.); TRITON ®Series (purchased from Union Carbide Corp., Danbury, Conn.); SURFONIC ® Series (purchased from Texaco Chemical Company, Houston, Tex.); ETHOQUAD ® Series (purchased from Akzo Chemical Inc., Chicago, Ill.); ARMEEN ® Series (purchased from Akzo Chemical Inc., Chicago, Ill.); SURFYNOL ® Series (purchased from AirProducts and Chemicals, Inc. Allentown, Pa.); and ETHOMEEN ® The following series of surfactants were available: Series 27,000, 40,000, 44,000, 46,000, and 47,000 (purchased from Lubrizol); Series 300 (cationic), 305 (non-anionic), 306 (cationic), 342, 345 (non-anionic), 348, 349, 378, 3481 (cationic), BYK Dynwet 810 (cationic), and polyether siloxane copolymer Tego Wet KL 245 (purchased from Evonik). Surfactants can be used alone or in combination, and the dosage can range from 0.1% to 3% by weight, depending on the weight of the enamel and ceramic inkjet ink composition.

[0068] Other additives

[0069] Ceramic inkjet ink compositions according to various embodiments may optionally include additional additives compatible with other components of the composition, which impart any number of adjustments or modifications to the desired rheological, physical, and optical properties of the ceramic inkjet ink composition. Such properties include, but are not limited to, stability, pH adjustment, smear resistance, preservatives, viscosity, surface tension, penetration, optical density, color depth, adhesion, gloss resistance, resolubility, defoaming, preservatives, anti-settling, rheology modifiers, and anti-scabbing properties. Additives that may be included in enamel inkjet and ceramic inkjet ink compositions to address the aforementioned properties include, but are not limited to, additives for stability, pH adjustment, smear resistance, preservatives, viscosity, surface tension, penetration, optical density, color depth, adhesion, gloss resistance, resolubility, defoaming, preservatives, anti-settling, rheology modifiers, and anti-scabbing antioxidants, UV absorbers, chelating agents, conductivity modifiers, oxygen absorbers, anti-curling agents, and fragrances.

[0070] For example, in addition to water and solvents, enamel and ceramic inkjet ink compositions according to various embodiments may include humectants to reduce the evaporation rate of the water and solvent components and prevent the composition from drying out in the nozzles of the inkjet printer printhead (which may occur during the lag period). Examples of suitable humectants with high hygroscopicity and water solubility include, but are not limited to: polyols (e.g., glycerol, propylene glycol, and ethylene glycol), alcohol ethers (e.g., diethylene glycol, triethylene glycol), lactams (e.g., 2-pyrrolidone, urea compounds such as urea, 1,3-dimethylimidazolone), sugars (e.g., sorbitol), 1,4-cyclohexanediol, 1-methyl-2-piperidinone, N-ethylacetamide, 3-amino-1,2-propanediol, ethylene carbonate; butyrolactone and Liponic EG-1, etc. Humectants may be used alone or in combination and may range from 0% to 5% by weight based on the weight of the enamel and ceramic inkjet ink composition.

[0071] Examples of suitable pH adjusters for adjusting or buffering ceramic inkjet ink compositions to a desired pH include, but are not limited to, alkali metal hydroxides, alkali metal carbonates and bicarbonates, triethylamine, dimethylethanolamine, triethanolamine, inorganic acids, hydrochloric acid, and sulfuric acid. The pH adjuster may be used alone or in combination, and may be in amounts from 3% to 10% by weight, based on the weight of the enamel inkjet and ceramic inkjet ink compositions.

[0072] Examples of suitable antisettling agents for improving the antisettling properties of pigments and other solids in enamel and ceramic inkjet ink compositions at the expense of increased viscosity include, but are not limited to, BYK-Chemie GmbH reagents sold under the trade names BYK-410, BYK-415, and BYK-430, which can be used alone or in combination with other additive materials such as binders, rheology modifiers, and other additives such as fumed silica (Aerosil 200). Antisettling agents can be used alone or in combination, and can be in amounts from 0% to 3% by weight, depending on the weight of the enamel and ceramic inkjet ink composition.

[0073] Examples of suitable rheology modifiers for adjusting the rheological properties of enamel and ceramic inkjet ink compositions include, but are not limited to, BYK 7420, polyvinylpyrrolidones such as PVP K-30 and PVP K-90, etc. The rheology modifiers may be used alone or in combination, in amounts ranging from 0% to 2% by weight based on the weight of the enamel and ceramic inkjet ink composition.

[0074] When applied to a substrate, examples of suitable penetrants for reducing bleed-out ceramic inkjet ink compositions include, but are not limited to, alkyl alcohols (e.g., ethanol), glycol ethers (e.g., ethylene glycol monomethyl ether), glycols (e.g., 1,2-alkyl glycol), formamide, acetamide, dimethyl sulfoxide, sorbitol, and sulfolane. Penetrants can be used alone or in combination, and can range from 1% to 5% by weight, depending on the weight of the enamel inkjet and ceramic inkjet ink compositions.

[0075] Examples of suitable defoamers for suppressing foam formation include, but are not limited to, silicone-based or non-silicone defoamers. Commercially available defoamers include, but are not limited to, DC62, DC65, DC 68, DC71, and DC74 (available from Dow Corning); TegoAirex ® Models 900, 910, 916, 920, 931, 936, 940, 944, 945, 950, 962, 980, 986, 901W, 902W, 904W, and TEGO FOAMEX N, FOAMEX 1488, 1495, 3062, 7447, 800, 8030, 805, 8050, 810, 815N, 822, 825, 830, 831, 835, 840, 842, 843, 845, 855, 860 and 883, TEGO FOAMEX K3, TEGO FOAMEX K7 / K8 and TEGO TWIN 4000 (purchased from Evonik Industries / Tega); Tergitol ®L-61, L-62, L-64, and L-101 (purchased from Dow Chemical); BYK-066N, 088, 055, 057, 1790, 020, BYK-A 530, 067A, and BYK 354 (purchased from BYK); Agitan 120, 150, 160, 271, 290, 298, 299, 350, 351, 731, 760, 761, and 777 (purchased from Munzing); and Surfynol 104PA, AD01, DF-110, DF-58, DF-62, DF-66, DF-695, DF-70, and MD-20 (purchased from Air Products), etc. The defoamer can be used alone or in combination, and the amount can range from 0.1% to 3% by weight, depending on the weight of the enamel inkjet and ceramic inkjet ink composition.

[0076] Examples of suitable preservatives (such as biocides and fungicides) for inhibiting the growth of microorganisms in ceramic inkjet ink compositions include, but are not limited to, sodium benzoate, sodium pentachlorophenolate, sodium 2-pyridinium-1-oxide, sodium sorbate, sodium dehydroacetate, benzisothiazolinone, 1,2-dibenzothiazolin-3-one, 1-(3-chloroallyl)-3,5,7-triaza-1-aza-1-adamantane chloride (CTAC), methylisothiazolinone, and chloromethylisothiazolinone. Commercially available biocides include UCARCIDE. ® 250 (purchased from Union Carbide Company), Proxel ® CRL, Proxel ® BDN, Proxel ® GXL, Proxel ® XL-2, Proxel ® TN (purchased from Arch Chemicals), Dowicil ® (Purchased from DowChemical), Nuosept ® (Purchased from Huls America, Inc.), Omidines ® (Purchased from Olin Corp.), Nopcocides ® (Purchased from Henkel Corp.), Troysans ®(Purchased from Troy Chemical Corp.), bromo-nitro-propanediol, isothiazolinone, ethylenedioxydimethylethanol or butylcarbamate iodopropynyl ester (all sold under the trade name Intercide, purchased from Akcros Chemicals), Nipacide (purchased from Clariant), sodium dehydroacetate (Geogard 111S, purchased from Lonza), sodium benzoate (Vancide 51, purchased from RT Vanderbilt), sodium pyridylthiolate-1-oxide (Sodium Omadine, purchased from Arch Chemicals), sodium salt of o-phenylphenol (Dowicide A, purchased from DOWChemical), ethyl para-hydroxybenzoate (Nipastat Sodium, purchased from Aako), and XBINX ® (Purchased from PMC Specialties Group, Inc.) etc. Preservatives can be used alone or in combination, and the amount can be less than 1% by weight, depending on the weight of the enamel inkjet and ceramic inkjet ink composition.

[0077] Enamel

[0078] According to various embodiments, the glaze can be a composition of a fusible glass material capable of promoting the fusibility of the glaze inkjet and ceramic inkjet ink compositions of the present invention. The glaze is typically derived from glaze powder, formed by adding solvents, dispersants, and optional additives to the glaze powder to form a concentrated glaze paste. The concentrated glaze paste contains metal oxides of ceramic pigments, which have been fused together in a suitable proportion by grinding in a high-shear mill to form a homogeneous whole, and then reacted together by firing in a kiln at an elevated temperature for a sufficient time. In various embodiments, the kiln firing time can range from 30 minutes to 3 hours, and the elevated temperature can range from 800°C to 1200°C, and is preferably 850°C. After firing, the metal oxides form a glassy matrix of insoluble flakes or granules. The purpose of fusion is to render any soluble and / or toxic components insoluble by combining them with the metal oxides (such as silicates). Re-grinding or granulating the glassy matrix into fine particles or glaze powder, also known in the ceramics industry as "fuse," such as CERABIEN, for example. ® ZR (purchased from Kuraray America, Inc., NY, NY). Concentrated glaze pastes or glaze inkjet compositions of ceramic metal oxides can be fully sintered by firing in a manner that yields suitable aesthetics, fluid-resistant qualities, minimal or no porosity, and generally becomes resistant to abrasion and chemical attack.

[0079] According to various embodiments, enamel inkjet compositions may also incorporate water as a co-solvent. Water can reduce the toxicity of certain oxides used (such as PbO) to produce enamel powder. The enamel should be able to bond to the surface of the dental material substrate, provide coverage to the entire surface of the dental material substrate, and become fused with the dental material substrate upon firing at elevated temperatures for a sufficient time. Firing transforms the dental material substrate into a robust and continuous structure. Enamels are typically obtained by rapidly quenching molten micronized ceramic pigments into a glassy matrix. Typically, the firing cycle time for the glassy matrix will last up to 24 hours or longer. However, the firing time can be significantly reduced to 25 to 60 minutes using a rapid firing kiln. Using metal oxide ceramic pigments and firing these metal oxide ceramic pigments achieves optimal uniformity and rapid reaction of the metal oxides in the enamel.

[0080] According to various embodiments, the metal oxide particles of the concentrated glaze paste or glaze inkjet composition should be small enough (e.g., micronized) to allow the glaze inkjet composition and the ceramic inkjet ink composition formulated from the glaze inkjet composition to flow freely through the nozzle of the inkjet printing apparatus. To achieve this, the metal oxide ceramic pigments can be ground (e.g., wet-milled) to an average particle size of less than 1 micrometer, and preferably to an average particle size in the range of less than 5 micrometers to 0.05 micrometers, and more preferably to an average particle size in the range of less than 1 micrometer to 0.05 micrometers. The micronization or nanoparticle size of the metal oxide ceramic pigments is accompanied by a particle size distribution in the range of D10 to D98. To establish and maintain the small particle size and particle size distribution of the metal oxide ceramic pigments, dispersants capable of adjusting or regulating the resolubility, good jetting, sedimentation, coefficient of expansion, surface tension, storage stability, transparency, and color gamut of the ceramic inkjet ink composition and the glaze inkjet composition can be added to the ceramic inkjet ink composition and the glaze inkjet composition along with other additives.

[0081] Ceramic inkjet ink composition

[0082] Ceramic inkjet ink compositions according to various embodiments can be formulated, for example, by first preparing a precursor transparent glaze inkjet composition, which can be formed from a glaze-forming material, such as glaze powder, CERABIEN. ® ZR (purchased from Kuraray America, Inc., NY) was prepared by wet milling the enamel powder under high shear in the presence of a grinding medium (in a solvent) and a dispersant. During wet milling of the enamel powder, a transparent, concentrated enamel paste, typically with a solid load or content of 40% to 70% by weight, is produced. Next, colored dyes and pigments, such as those from CERABIEN, can be added.® The colored dye made from ZR (purchased from Kuraray America, Inc., NY, NY) is combined with a transparent, concentrated enamel paste to obtain a colored enamel paste mixture.

[0083] The combined colored paste mixture can then be wet-milled under high shear in the presence of abrasive media, and the pigment particle size and particle size distribution of the combined colored paste mixture are periodically monitored and measured during wet milling until the target pigment particle size and particle size distribution are achieved. Various embodiments achieve many of the objectives described herein by ensuring that the pigments in the colored enamel paste mixture are well dispersed in the solvent and have nanoscale dimensions (e.g., pigment particle size less than 1 μm) so that the resulting ceramic inkjet ink composition formulated from the colored enamel paste mixture flows through the small nozzles of the printhead of an inkjet printer. Once the target particle size and particle size distribution are achieved, the wet milling of the combined colored paste mixture is stopped, and a concentrated colored dye paste is obtained. Nanoscale pigments are typically obtained through a wet milling process.

[0084] Next, in some embodiments, a diluted solution of solvent, surfactant, and dispersant can be mixed with a concentrated color dye paste at ambient temperature to produce a ceramic inkjet ink composition that can be applied to the surface of a dental material substrate, according to various embodiments.

[0085] Additives, such as dispersants or anti-settling agents, may be optionally added to the combined colored paste mixture before or simultaneously with the dispersion paste mixture. These additives are considered essential to achieve the desired physical and optical properties of ceramic inkjet ink compositions and enamel inkjet compositions, as these properties are altered once the compositions are deposited on the surface of dental material substrates and exposed to firing. The amount of additive added ranges from 1% to 20% by weight. The firing process itself requires a certain combination of temperature and time, as well as temperature reduction requirements that may need to be addressed, for example, by adding additives. This is because developing ceramic inkjet ink compositions with reduced firing requirements while maintaining high chemical stability is extremely difficult and usually requires trade-offs between firing time and temperature, as well as other properties of the composition.

[0086] Dental material substrate

[0087] Ceramic inkjet ink compositions for inkjet printing on dental material substrates, such as dental models, dental restorations, occlusal braces, clear aligners, surgical guides, complete dentures, partial dentures, bridges, crowns, and artificial teeth, can be formulated according to various embodiments. These dental material substrates can be manufactured by milling a raw substrate or by using a 3D printer (printing resin or nano-ceramic hybrid resin) to form a substrate that mimics the biomass and teeth of the gums, oral cavity, and teeth. Since the resin will be used to manufacture the dental material for this specific end use, it is important to classify the resin as a high-end (Class 1) biocompatible resin that meets the bioassay requirements for medical devices as specified by the Food and Drug Administration (FDA) according to ISO 10993-1. The chemical properties of these high-end biocompatible resins include ceramic crown polymers, leucite glass ceramics, natural dentin, and lithium disilicate, among others. Examples of commercial resins that meet the FDA's biocompatibility requirements include, but are not limited to, resins such as hydroxypropyl cellulose sold and traded under the following trade names: Klucel E., Onyx by Sprint Ray; IC-131 by Glidwell; FreePrint Temp UV by Detax; Water Washable Model Resin by Phrozen; Acetomax; Dental SG Resin by Formlabs; Smile Guard Resin Proto 3000 by DeskTop Health; Flexcure; Prime Print; Xdent ModelOrtho Dental Resin; and Plonext Removable Die Model Resin.

[0088] Printing test of enamel inkjet and ceramic inkjet ink compositions

[0089] Example enamel and ceramic inkjet ink compositions according to various embodiments were printed using a Dimatix DMP2800 printer or an industrial printer equipped with a Kyocera KJ4B or Konica Minolta 1024 printhead. All examples were printed onto dental material substrates and visually evaluated. The printed dental material substrates were printed in two different ways.

[0090] According to the first method (i.e., printing scheme 1): As a first stage, an inkjet image is sprayed onto the dental material substrate crown using the enamel inkjet composition according to the embodiment, and then the composition is dried for staining. As a second stage, enamel is applied, which requires spraying several layers of the enamel inkjet composition according to the embodiment onto the top of the dental material substrate restoration to achieve the desired enamel thickness, and each layer is dried using an infrared dryer during printing (at each step). The enamel on the dental material substrate crown is then fused to the dental material crown at elevated temperatures in an oven.

[0091] According to the second method (i.e., printing scheme 2): As a first stage, a small layer of enamel is sprayed onto the dental material substrate crown using an enamel inkjet composition (enamel) according to the embodiment, and then the composition is dried using an infrared dryer during printing (at each step) for pre-enamelting. As a second stage, an image is sprayed onto the dental material substrate crown using an enamel inkjet composition according to the embodiment, and then the composition is dried for staining. As a third stage, enamel is applied by spraying enamel onto the top of the dental material substrate crown using an enamel inkjet composition according to the embodiment, and then the composition is dried using an infrared dryer during printing (at each step). The enamel on the dental material substrate crown is then fused to the dental material crown at an elevated temperature in an oven. If the printed substrate examples exhibit good jetting ability and printed image characteristics (i.e., excellent line straightness, good uniform color density, no edge bleeding, and minimal dot gain), they are considered qualified. All printed substrate examples are qualified and exhibit good jetting ability and printed image characteristics.

[0092] Examples

[0093] The following examples illustrate specific embodiments of the present invention and are not intended to, nor should be construed as limiting the scope of the invention in any way, and should not be interpreted as such.

[0094] Example 1

[0095] Milling media

[0096] In a mixing tank, at ambient temperature and while stirring, 95 g of dipropylene glycol methyl ether solvent was slowly added to 5 g of polyvinylpyrrolidone (PVP30) adhesive resin until the mixture was completely dissolved in the solvent. The completely dissolved mixture formed 100 g of wet grinding media with a resin content of 5% by volume.

[0097] Example 2

[0098] Concentrated enamel paste

[0099] In a mixing tank or container, combine 250g of the wet grinding media prepared in Example 1, 119g of dipropylene glycol methyl ether solvent, 111g of solvent-free dispersant (Disperbyk), and 600g of CERABIEN. ® ZR (enamel powder, purchased from KurarayAmerica, Inc., NY, NY) and 200 g of hydrophilic fumed silica (Aerosil 200) antisettling agent were added together to produce a mixture. The mixture was thoroughly mixed and transferred to a wet milling station for wet milling at high shear at ambient temperature. The particle size of the mixture was measured every 6 hours until the particles maintained a D98 particle size distribution and a particle size of approximately 0.8 μm to 1 μm (i.e., the D98 value Z-average particle size measured using a Malvern Zetasizer Nano-ZS). Once the desired particle size was achieved, the wet milling of the mixture was stopped, yielding 1000 g of concentrated enamel paste.

[0100] Characterization of the concentrated glaze paste showed: a total solids content of 45% by weight; an additive content of 3.0% by volume; a resin content of 1.3% by volume; and other component contents of 0.10% by volume. The physical properties of the concentrated glaze paste were also measured, providing viscosities ranging from 43 mPa·s to 110 mPa·s at 30°C and a shear rate of 400, and from 35 mPa·s to 85 mPa·s at 30°C and a shear rate of 1000.

[0101] Example 3

[0102] Concentrated brown stain enamel paste

[0103] In a mixing tank or container, 20 g of the wet grinding media prepared in Example 1, 229 g of dipropylene glycol methyl ether solvent, and 100 g of (solvent-free) dispersant (Disperbyk) were added together to produce a mixture. Next, 650 g of CERABIEN was added. ®A brown dye powder pigment made from ZR (enamel powder, purchased from Kuraray America, Inc., NY, NY) and 1 g of hydrophilic fumed silica antisettling agent (Aerosil 200) were mixed thoroughly and transferred to a wet milling station for wet milling at high shear at ambient temperature. The particle size of the mixture was measured every 6 hours until the particles maintained a D98 particle size distribution and a particle size of approximately 0.8 to 1 micrometer (i.e., the D98 value Z-average particle size measured using a Malvern Zetasizer Nano-ZS). Once the desired particle size was reached, the wet milling of the mixture was stopped, yielding 1000 g of concentrated brown dye paste.

[0104] Characterization of the concentrated brown dye enamel paste showed the following: total solids content 63% by weight; additive content 10.0% by volume; resin content 0.1% by volume; and other component content 0.1% by volume. The physical properties of the concentrated brown dye paste were also measured, providing viscosities of 120 mPa·s to 140 mPa·s at 30°C and a shear rate of 400, and viscosities of 110 mPa·s to 120 mPa·s at 30°C and a shear rate of 1000.

[0105] Example 4

[0106] Concentrated blue stain enamel paste

[0107] In a mixing tank or container, 20 g of the wet grinding media prepared in Example 1, 230 g of dipropylene glycol methyl ether solvent, and 100 g of (solvent-free) dispersant (Disperbyk) were added together to produce a mixture. Next, 650 g of CERABIEN was added. ® Blue dye powder pigment made from ZR (enamel powder, purchased from Kuraray America, Inc., NY, NY) was thoroughly mixed and transferred to a wet milling station for wet milling at high shear at ambient temperature. The particle size of the mixture was measured every 3 hours until the particles maintained a D98 particle size distribution and a particle size of approximately 0.8 to 1 micrometer (i.e., the D98 value Z-average particle size measured using a Malvern Zetasizer Nano-ZS). Once the desired particle size was reached, wet milling of the mixture was stopped, yielding 1000 g of concentrated blue dye paste.

[0108] Characterization of the concentrated blue dye enamel paste showed the following: total solids content 64% by weight; additive content 10% by volume; resin content 0.1% by volume; and other component content 0% by volume. The physical properties of the concentrated blue dye enamel paste were also measured, providing viscosities of 140 mPa·s to 150 mPa·s at 30°C and a shear rate of 400, and viscosities of 120 mPa·s to 140 mPa·s at 30°C and a shear rate of 1000.

[0109] Example 5

[0110] Concentrated yellow stain enamel paste

[0111] In a mixing tank or container, 20 g of the wet grinding media prepared in Example 1, 230 g of dipropylene glycol methyl ether solvent, and 100 g of solvent-free dispersant (Disperbyk) were added together to produce a mixture. Next, 650 g of CERABIEN was added. ® Yellow dye powder pigment made from ZR (enamel powder, purchased from Kuraray America, Inc., NY, NY) was thoroughly mixed and transferred to a wet milling station for wet milling at high shear at ambient temperature. The particle size of the mixture was measured every 3 hours until the particles maintained a D98 particle size distribution and a particle size of approximately 0.6 to 0.8 micrometers (i.e., the Z-average of the D98 particle size measured using a Malvern Zetasizer Nano-ZS). Once the desired particle size was reached, wet milling of the mixture was stopped, yielding 1000 g of concentrated yellow dye paste.

[0112] Characterization of the concentrated yellow dye paste showed: a total solids content of 63% by weight; an additive content of 10% by volume; a resin content of 0.1% by volume; and a content of 0% by volume of other components. The physical properties of the concentrated yellow dye paste were also measured, providing a viscosity of 70 mPa·s to 80 mPa·s at 30°C and a shear rate of 400, and a viscosity of 65 mPa·s to 75 mPa·s at 30°C and a shear rate of 1000.

[0113] Example 6

[0114] Slurry inkjet composition

[0115] In a stirred tank or container, a diluted solution of 384.5 g of dipropylene glycol methyl ether solvent and 15 g of propylene glycol methyl ether solvent was added to 0.5 g of surfactant (BYK 342) and 30 g of (solvent-free) dispersant (Disperbyk 111). The diluted solution was combined with 570 g of the concentrated enamel paste prepared in Example 2, and the resulting mixture was thoroughly mixed at ambient temperature to obtain 1000 g of enamel inkjet composition. The composition was filtered using a 5-micron filter and subsequently a 2-micron filter to remove any excessively large particles.

[0116] Characterization of the enamel inkjet composition revealed the following: 25.7 wt% total solids content; 4.71 vol% additive content; 0.7 vol% resin content; 0.05 vol% surfactant content; 23.1 vol% cosolvent content; and 0.06 vol% other component content. The physical properties of the enamel inkjet composition were measured to obtain a surface tension of 27.6 mNm at 30°C; viscosity from 15 mPa·s to 25 mPa·s at a shear rate of 400, and viscosity from 16 mPa·s to 23 mPa·s at 30°C and a shear rate of 1000; and a density of 1130 kg / m³ at 25°C.

[0117] Example 7

[0118] Brown stain enamel ceramic inkjet ink composition

[0119] In a high-shear mixer, 150g of the CERABIEN product prepared in Example 2 was mixed. ® A concentrated glaze paste made from ZR (glaze powder, purchased from Kuraray America, Inc., NY, NY) and 400g of the CERABIEN powder prepared in Example 3. ® A concentrated brown dye enamel paste made from ZR (enamel powder, purchased from Kuraray America, Inc., NY, NY) was combined to provide a concentrated mixture. The concentration of the concentrated mixture was then adjusted to provide a total pigment to concentrated brown dye enamel paste ratio of 2.5. A diluted solution of 434.5 g of dipropylene glycol methyl ether solvent, 15 g of propylene glycol methyl ether solvent, and 0.5 g of surfactant (BYK 342) was then combined with the concentrated enamel paste and concentrated brown dye enamel paste in a high-shear mixer. The resulting mixture was then thoroughly mixed at ambient temperature to obtain 1000 g of brown dye enamel ceramic inkjet ink composition, which was filtered using a 5-micron filter and subsequently a 2-micron filter to remove any excessively large particles.

[0120] Characterization of the brown dye enamel ceramic inkjet ink composition showed the following: 31.8 wt% solids content; 9.0 vol% enamel content; 26 vol% brown dye content; 4.45 vol% additive content; 0.2 vol% resin content; 0.05 vol% surfactant content; 1.5 vol% cosolvent content; and 0.06 vol% other component content. The physical properties of the brown dye enamel ceramic inkjet ink composition were measured to obtain a surface tension of 27.7 mNm at 30°C; viscosity of 14 mPa·s to 17 mPa·s at 30°C and a shear rate of 400, and viscosity of 13 mPa·s to 15 mPa·s at 30°C and a shear rate of 1000; and a density of 1210 kg / m³ at 25°C.

[0121] Example 8

[0122] Blue stain enamel ceramic inkjet ink composition

[0123] In a high-shear mixer, 150g of the CERABIEN product prepared in Example 2 was mixed. ® A concentrated glaze paste made from ZR (glaze powder, purchased from Kuraray America, Inc., NY, NY) and 400g of the CERABIEN powder prepared in Example 4. ® A concentrated blue dye enamel paste made from ZR (enamel powder, purchased from Kuraray America, Inc., NY, NY) was combined to provide a concentrated mixture. The concentration of the concentrated mixture was adjusted to provide a total pigment to concentrated blue dye enamel paste ratio of 2.5. A diluted solution of 434.5 g dipropylene glycol methyl ether solvent, 15 g propylene glycol methyl ether solvent, and 0.5 g surfactant (BYK 342) was then combined with the concentrated enamel paste and concentrated blue dye enamel paste in a high-shear mixer. The resulting mixture was then thoroughly mixed at ambient temperature to obtain 1000 g of blue dye enamel inkjet ink composition, which was filtered using a 5-micron filter and subsequently a 2-micron filter to remove any excessively large particles.

[0124] Characterization of the blue-dyed glaze ceramic inkjet ink composition showed the following: 32.7 wt% solids content; 9.0 vol% glaze content; 26 vol% blue dye content; 4.45 vol% additive content; 0.2 vol% resin content; 0.05 vol% surfactant content; 1.5 vol% co-solvent content; and 0.02 vol% other component content. The physical properties of the blue dye glaze ceramic inkjet ink composition were measured to obtain a surface tension of 29.4 mNm at 30°C; viscosity of 13 mPa·s to 15 mPa·s at 30°C and a shear rate of 400, and viscosity of 14 mPa·s to 16 mPa·s at 30°C and a shear rate of 1000; and a density of 1260 kg / m³ at 25°C.

[0125] Example 9

[0126] Yellow stain enamel ceramic inkjet ink composition

[0127] In a high-shear mixer, 150g of the CERABIEN product prepared in Example 2 was mixed. ® A concentrated glaze paste made from ZR (glaze powder, purchased from Kuraray America, Inc., NY, NY) and 400g of the CERABIEN powder prepared in Example 5. ® A concentrated yellow dye enamel paste made from ZR (enamel powder, purchased from Kuraray America, Inc., NY, NY) was combined to provide a concentrated mixture. The concentration of the concentrated mixture was adjusted to provide a total pigment to concentrated yellow dye enamel paste ratio of 2.5. A diluted solution of 434.5 g dipropylene glycol methyl ether solvent, 15 g propylene glycol methyl ether solvent, and 0.5 g surfactant (BYK 342) was then combined with the concentrated enamel paste and concentrated yellow dye enamel paste in a high-shear mixer. The resulting mixture was then thoroughly mixed at ambient temperature to obtain 1000 g of yellow dye enamel ceramic inkjet ink composition, which was filtered using a 5-micron filter and subsequently a 2-micron filter to remove any excessively large particles.

[0128] Characterization of the yellow stain glaze ceramic inkjet ink showed the following: 31.8 wt% solids content; 9.0 vol% glaze content; 26 vol% yellow dye content; 4.45 vol% additive content; 0.2 vol% resin content; 0.05 vol% surfactant content; 1.5 vol% co-solvent content; and 0.02 vol% other component content. The physical properties of the yellow dye glaze ceramic inkjet ink composition were measured to obtain a surface tension of 29.9 mNm at 30°C; viscosity of 12 mPa·s to 15 mPa·s at 30°C and a shear rate of 400, and viscosity of 14 mPa·s to 16 mPa·s at 30°C and a shear rate of 1000; and a density of 1260 kg / m³ at 25°C.

[0129] The prior description of the disclosed embodiments is provided to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not intended to be limited to the embodiments shown herein, but should be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A ceramic inkjet ink for use in dental material substrates, the ceramic inkjet ink comprising: Ceramic pigment, wherein the ceramic pigment comprises: Metal oxide solid particles, wherein the metal oxide solid particles have a submicron particle size of less than 1 micrometer in a particle size distribution of D98 to D10; and Inorganic pigment solid particles, wherein the inorganic pigment solid particles have a submicron particle size of less than 1 micrometer in a particle size distribution of D98 to D10; Solvent; and Dispersant; The ink has a solid particle load of about 10% to about 50% by weight, the ink exhibits good jetting ability when uniformly jetted onto the surface of the dental material substrate by an inkjet printer, and the ink is able to fuse to the surface of the dental material substrate by firing at elevated temperatures and retain the aesthetic color characteristics of the ink after firing.

2. The ceramic inkjet ink according to claim 1, wherein the metal oxide solid particles have a submicron particle size of about 0.85 μm to about 0.93 μm in a D98 particle size distribution.

3. The ceramic inkjet ink according to claim 1, wherein the metal oxide solid particles have a submicron particle size of about 0.6µm to about 0.66µm in a D90 particle size distribution.

4. The ceramic inkjet ink according to claim 1, wherein the metal oxide solid particles have a submicron particle size of about 0.39µm to about 0.4µm in a D50 particle size distribution.

5. The ceramic inkjet ink according to claim 1, wherein the metal oxide solid particles have a submicron particle size of about 0.2µm to about 0.24µm in a D10 particle size distribution.

6. The ceramic inkjet ink according to claim 1, wherein the amount of metal oxide solid particles is from about 1% to about 10% by weight, based on the weight of the ceramic inkjet ink.

7. The ceramic inkjet ink according to claim 1, wherein the inorganic pigment solid particles are selected from chromium oxide, titanium dioxide, and iron oxide or mixtures thereof.

8. The ceramic inkjet ink according to claim 1, wherein the inorganic pigment solid particles have a submicron particle size of about 0.85µm to about 0.93µm in a D98 particle size distribution.

9. The ceramic inkjet ink according to claim 1, wherein the inorganic pigment solid particles have a submicron particle size of about 0.6µm to about 0.66µm in a D90 particle size distribution.

10. The ceramic inkjet ink of claim 1, wherein the inorganic pigment solid particles have a submicron particle size of about 0.39 µm to about 0.4 µm in a D50 particle size distribution.

11. The ceramic inkjet ink of claim 1, wherein the inorganic pigment solid particles have a submicron particle size of about 0.2 µm to about 0.24 µm in a D10 particle size distribution.

12. The ceramic inkjet ink according to claim 1, wherein the amount of inorganic pigment solid particles is from about 1% to about 10% by weight, based on the weight of the ceramic inkjet ink.

13. The ceramic inkjet ink according to claim 1, wherein the solvent is selected from polar solvents, non-polar solvents, hydrophobic solvents, hydrophilic solvents, and aqueous solvents, or mixtures thereof.

14. The ceramic inkjet ink according to claim 13, wherein the solvent is selected from C 12 To C 40 Hydrocarbons, traded under the commercial brands D40, D80, and D120 (purchased from Exxsol), including dearomatized hydrocarbons of isoalkanes, alkanes, and cycloalkanes, dearomatized aliphatic hydrocarbons, and C 12 To C 40 Aliphatic solvents, C 12 To C 40 Straight-chain alkanes, such as alkanes, ester solvents; glycols, such as methyl glycol, ethyl glycol, butyl glycol, alkylene glycols, alkylene glycol ethers or ether acetates, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol butyl ether, diethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether, dipropylene glycol ethyl ether, dipropylene glycol methyl ether, ethylene glycol butyl ether, ethylene glycol ethyl ether, ethylene glycol... Isopropyl alcohol ethers, ethylene glycol methyl ethers, ethylene glycol propyl ethers, glyceryl carbonate, N-methyl-2-pyrrolidone, glycerol, propylene glycol, glycol ethers such as propylene glycol ethyl ether, propylene glycol ethyl ether acetate, propylene glycol methyl ether, propylene glycol n-propyl ether, triethylene glycol butyl ether, triethylene glycol methyl ether, tripropylene glycol, tripropylene glycol methyl ether; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, polyols, ethoxypropanol, methoxypropanol Butanol, ethylene glycol, propylene glycol, dipropylene glycol, glycerol, and polyethylene glycol, etc.; ketones and ketols, such as acetone, diacetone alcohol, diacetone propanol and methyl ethyl ketone, methyl butyl ketone, cyclohexanone; ethers, such as methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methoxypropyl acetate, ethyl-3-ethoxy-propanol, tetrahydrofuran, dioxane and alkyl ethers, ethers of polyols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, di(ethylene glycol) monomethyl ether; nitrogen-containing solvents, such as 2-pyrrolidone and N-methyl-2-pyrrolidone; sulfur-containing solvents, such as 2,2'-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone and sulfolane; and sugars and their derivatives, such as glucose, ethylene oxide adducts of glycerol and ethylene oxide adducts of diglycerol propylene glycol and / or dipropylene glycol, N-methylpyrrolidone and urea, and mixtures thereof.

15. The ceramic inkjet ink of claim 1, wherein the amount of solvent is from about 30% to about 80% by weight, based on the weight of the ceramic inkjet ink.

16. The ceramic inkjet ink according to claim 1, wherein the dispersant is selected from polymer dispersion resins, such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylate copolymer, acrylic acid-acrylate copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic anhydride copolymer, etc. Acid copolymers, vinyl acetate-maleate copolymers, vinyl acetate-crotonic acid copolymers, and vinyl acetate-acrylic acid copolymers, and their salts, etc.; examples of suitable copolymer dispersion resins include, but are not limited to, random copolymers, block copolymers, alternating copolymers, and graft copolymers of any form; examples of suitable dispersion resin salts include, but are not limited to, salts of sodium hydroxide, potassium hydroxide, and basic compounds such as ammonia, ethylamine, diethanolamine, triethanolamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, diethanolamine, triethanolamine, triisopropanolamine, dimethylethanolamine, aminomethylpropanol, and morpholine, and mixtures thereof.

17. The ceramic inkjet ink of claim 1, wherein the amount of dispersant is from about 1% by weight to about 20% by weight, based on the weight of the ceramic inkjet ink.

18. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink further comprises additives selected from the following: stabilizing additives, pH adjusting additives, anti-fouling additives, preservatives, viscosity adjusting additives, surface tension additives, penetrating additives, adhesion additives, resolubilizing additives, defoaming additives, preservatives, anti-settling additives, rheology modifying additives, chelating agents, oxygen absorbers, and mixtures thereof.

19. The ceramic inkjet ink according to claim 1, wherein the amount of additive is from 0% by weight to about 3% by weight, based on the weight of the ceramic inkjet ink.

20. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink further comprises a surfactant selected from the group consisting of alkane sulfonates, α-olefin sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, acylmethyl taurate, dialkyl sulfosuccinate, alkyl sulfates, sulfurized olefins, polyoxyethylene alkyl ether phosphates, polycarboxylic acids, monoglycerides of phosphate, amphoteric surfactants, alkylpyridinium salts, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamides, glyceryl alkyl esters, dehydrated sorbitol alkyl esters, and mixtures thereof.

21. The ceramic inkjet ink of claim 1, wherein the amount of surfactant is from about 0.1% by weight to about 3% by weight, based on the volume of the ceramic inkjet ink.

22. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink is at a jetting temperature of 400 s -1 up to 1000s -1 It has a viscosity in the range of about 12 mPa·s to about 25 mPa·s at shear rates within the range.

23. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink is at a jetting temperature of 400s. -1 It has a viscosity of about 12 mPa·s to about 25 mPa·s at a shear rate.

24. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink is at a jetting temperature of 1000s -1 It has a viscosity of about 12 mPa·s to about 25 mPa·s at a shear rate.

25. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink has a surface tension of about 20 mN / m to about 35 mN / m at 30°C.

26. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink has a density of approximately 1050 kg / m³ at 25°C. 3 Approximately 1300 kg / m 3 The density.

27. The ceramic inkjet ink according to claim 1, wherein the ceramic inkjet ink further comprises less than 10% elasticity.

28. The ceramic inkjet ink according to claim 1, wherein the ink retains its aesthetic color characteristics after being fired at a temperature of 800°C to 1300°C.

29. A concentrated enamel paste composition for use as a dental material substrate, said concentrated enamel paste composition comprising: Enamelled powder, said enamel powder comprising metal oxide solid particles having a submicron particle size of less than 1 micrometer in a particle size distribution in the range of D98 to D10; Solvent; Dispersants; and additive; The concentrated enamel paste composition has a solid particle load in the range of 10% to 70% by weight.

30. The concentrated enamel paste composition according to claim 29, wherein the metal oxide solid particles have a submicron particle size of about 0.85 μm to about 0.93 μm in a D98 particle size distribution.

31. The concentrated enamel paste composition according to claim 29, wherein the metal oxide solid particles have a submicron particle size of about 0.6 µm to about 0.66 µm in a D90 particle size distribution.

32. The concentrated enamel paste composition according to claim 29, wherein the metal oxide solid particles have a submicron particle size of about 0.39 μm to about 0.4 μm in a D50 particle size distribution.

33. The concentrated enamel paste composition according to claim 29, wherein the metal oxide solid particles have a submicron particle size of about 0.2 µm to about 0.24 µm in a D10 particle size distribution.

34. The concentrated enamel paste composition according to claim 29, wherein the amount of the metal oxide solid particles is from about 1% to about 10% by weight, based on the weight of the concentrated enamel paste.

35. The concentrated enamel paste composition according to claim 29, wherein the solvent is selected from polar solvents, nonpolar solvents, hydrophobic solvents, hydrophilic solvents, and aqueous solvents, or mixtures thereof.

36. The concentrated enamel paste composition according to claim 35, wherein the solvent is selected from C 12 To C 40 Hydrocarbons, traded under the commercial brands D40, D80, and D120 (purchased from Exxsol), including dearomatized hydrocarbons of isoalkanes, alkanes, and cycloalkanes, dearomatized aliphatic hydrocarbons, and C 12 To C 40 Aliphatic solvents, C 12 To C 40 Straight-chain alkanes, such as alkanes, ester solvents; glycols, such as methyl glycol, ethyl glycol, butyl glycol, alkylene glycols, alkylene glycol ethers or ether acetates, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol butyl ether, diethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monopropyl ether, dipropylene glycol ethyl ether, dipropylene glycol methyl ether, ethylene glycol butyl ether, ethylene glycol ethyl ether, ethylene glycol... Isopropyl alcohol ethers, ethylene glycol methyl ethers, ethylene glycol propyl ethers, glyceryl carbonate, N-methyl-2-pyrrolidone, glycerol, propylene glycol, glycol ethers such as propylene glycol ethyl ether, propylene glycol ethyl ether acetate, propylene glycol methyl ether, propylene glycol n-propyl ether, triethylene glycol butyl ether, triethylene glycol methyl ether, tripropylene glycol, tripropylene glycol methyl ether; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, polyols, ethoxypropanol, methoxypropanol Butanol, ethylene glycol, propylene glycol, dipropylene glycol, glycerol, and polyethylene glycol, etc.; ketones and ketols, such as acetone, diacetone alcohol, diacetone propanol and methyl ethyl ketone, methyl butyl ketone, cyclohexanone; ethers, such as methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methoxypropyl acetate, ethyl-3-ethoxy-propanol, tetrahydrofuran, dioxane and alkyl ethers, ethers of polyols, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, di(ethylene glycol) monomethyl ether; nitrogen-containing solvents, such as 2-pyrrolidone and N-methyl-2-pyrrolidone; sulfur-containing solvents, such as 2,2'-thiodiethanol, dimethyl sulfoxide, tetramethylene sulfone and sulfolane; and sugars and their derivatives, such as glucose, ethylene oxide adducts of glycerol and ethylene oxide adducts of diglycerol propylene glycol and / or dipropylene glycol, N-methylpyrrolidone and urea, and mixtures thereof.

37. The concentrated enamel paste composition according to claim 29, wherein the amount of solvent is from about 30% to about 80% by weight, based on the weight of the concentrated enamel paste.

38. The concentrated enamel paste composition according to claim 29, wherein the additive is selected from stabilizing additives, pH adjusting additives, anti-fouling additives, preservatives, viscosity adjusting additives, surface tension additives, permeability additives, adhesion additives, resolubilizing additives, defoaming additives, preservatives, anti-settling additives, rheology modifiers, chelating agents, oxygen absorbers, and mixtures thereof.

39. The concentrated enamel paste composition according to claim 29, wherein the amount of the additive is from 0% by weight to about 3% by weight based on the weight of the concentrated enamel paste.

40. The concentrated glaze paste composition according to claim 29, wherein the concentrated glaze paste composition further comprises a glaze concentrate having a viscosity in the range of about 43 mPa·s to about 150 mPa·s at a shear rate in the range of 400 to 1000.

41. The concentrated glaze paste composition according to claim 29, wherein the concentrated glaze paste composition further comprises a glaze concentrate having a viscosity of about 43 mPa·s to about 150 mPa·s at a shear rate of 400.

42. The concentrated glaze paste composition according to claim 29, wherein the concentrated glaze paste composition further comprises a glaze concentrate having a viscosity of about 35 mPa·s to about 140 mPa·s at a shear rate of 1000.

43. The concentrated enamel paste composition according to claim 29, wherein the composition has less than 10% elasticity.

44. A method for manufacturing digital ceramic inkjet ink for dental material substrates, the method comprising: In the presence of a first dispersant and a first anti-settling agent, concentrated glaze powder is wet-milled in a first solvent to produce a concentrated glaze paste having solid glaze powder particles with a particle size of 0.8 μm to 1 μm under a particle size distribution of D98. In the presence of a second dispersant and a second anti-settling agent, colored dye powder is wet-milled in a second solvent to produce a concentrated dye enamel paste with solid particles having a particle size of 0.8 μm to 1 μm under a particle size distribution of D98. The concentrated enamel paste and the concentrated dye enamel paste are mixed in a mixing mill to produce a dye-enamel mixture. A diluted solution of a mixture comprising solvent and additives is added to the dye-enamel mixture to produce a precursor colored ceramic inkjet composition having a solids content of about 20% to about 60% by weight based on the total weight of the colored ceramic inkjet ink composition and desired inkjet properties; and The precursor color ceramic inkjet composition is first filtered through a 5-micron pore size filter and then through a 2-micron pore size filter to remove any excessively large solid particles, thereby obtaining the digital ceramic inkjet ink with a viscosity of 12 mPa·s to 25 mPa·s under the jetting temperature and jetting conditions.

45. The method of claim 44, wherein the first solvent and the second solvent are the same, the first dispersant and the second dispersant are the same, and the first antisettling agent and the second antisettling agent are the same.

46. ​​The method of claim 44, wherein: The glaze powder concentrated by wet milling in solvents includes wet milling the glaze powder in a variety of solvents. The wet grinding media used in the wet grinding chamber are selected from zirconium oxide, silicon nitrite, silicon carbide, and mixtures thereof, and The digital ceramic inkjet ink has a solids loading content in the range of about 20% to about 60% by weight based on the total weight of the digital ceramic inkjet ink, and a solids particle size of 0.8 μm to 1 μm in a D98 particle size distribution.

47. The method of claim 44, wherein: The concentrated enamel dye paste comprises: Approximately 45% to approximately 85% by weight of metal oxides and inorganic pigments; about 2% by weight to about 20% by weight of a dispersant; and Approximately 10% to 55% by weight of solvent, The concentrated enamel dye paste is wet-milled in the presence of the dispersant and solvent in a wet milling chamber containing zirconium oxide, silicon nitrite, or silicon carbide grinding media.

48. A method for manufacturing ceramic inkjet ink for printing on a dental material substrate, the method comprising: The solid particulate components are processed to a particle size of 0.8 μm to 1 μm with a particle size distribution of D98; as well as An effective amount of additive is added to the solid particulate component to produce ink that can be dispensed from an inkjet printhead onto the surface of a three-dimensional dental material substrate having an irregular shape and uneven surface, while the three-dimensional dental material substrate is simultaneously translated and rotated below the inkjet printhead.