# US 12,214,545 B2 · Three-dimensional printing method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,214,545 B2 - Document ID: US12214545B2 - Status: Granted - Kind: B2 - Application number: 17/610,729 - Filed: 2020-04-30 - Published: 2022-07-14 - Granted: 2025-02-04 - Earliest claimed: 2019-05-15 - Assignees: Agency for Science, Technology and Research - Applicants: Agency for Science, Technology and Research - Inventors: Fuke Wang; Fei Wang - Web page: https://patentgrep.com/patent/US12214545B2 ## CPC - B29C 64/124: using layers of liquid which are selectively solidified - A61K 6/15: Compositions characterised by their physical properties - A61K 6/802: comprising ceramics - B29C 64/129: characterised by the energy source therefor, e.g. by global irradiation combined with a mask - B29C 64/314: Preparation - B33Y 40/10: Pre-treatment - C08F 2/44: Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers - C08K 3/14: Carbides - C08K 3/22: of metals - C08K 3/28: Nitrogen-containing compounds - C08L 33/08: Homopolymers or copolymers of acrylic acid esters - C08L 33/10: Homopolymers or copolymers of methacrylic acid esters - B29K 2033/08: {Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate} - B29L 2031/7536: {Artificial teeth} - B33Y 10/00: Processes of additive manufacturing - B33Y 70/10: Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials - B33Y 80/00: Products made by additive manufacturing - C08K 2003/2244: {of zirconium} - C08K 2003/2296: {of zinc} - C08K 2201/005: Additives being defined by their particle size in general - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) - B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract A method of three-dimensional printing an object having a varying degree of transmissivity to light along an axis of the object, the method comprising the steps of (a) providing a liquefied polymer resin having a plurality of particles therein, the particles being distributed in the liquefied polymer resin based on the density of the particles; and (b) polymerizing the liquefied polymer resin under conditions to form the object layer-by-layer. There is also provided a formulation for three-dimensional printing and a three-dimensional printed object. ## Claims ### Claim 1 A method of three-dimensional printing an object having a varying degree of transmissivity to light along an axis of said object, the method comprising the steps of: (a) providing a liquefied polymer resin having a plurality of particles therein, wherein said particles have densities in a range of 3 g/cm3 to 12 g/cm3, said particles being distributed in said liquefied polymer resin based on the density of said particles; and (b) polymerizing said liquefied polymer resin to form said object layer-by-layer by exposing each layer to light. ### Claim 2 (depends on 1) The method according to claim 1, further comprising, before said providing step (a), the steps of: (a1) providing a homogenous suspension of said particles within said liquefied polymer resin; and (a2) allowing the particles to distribute within said liquefied polymer resin based on their density values after a period of time. ### Claim 3 (depends on 1) The method according to claim 1, wherein said liquefied polymer resin further comprises a photoinitiator. ### Claim 4 (depends on 1) The method according to claim 1, wherein said liquefied polymer resin further comprises a photoadditive selected from a photoabsorber or a photostabilizer. ### Claim 5 (depends on 1) The method according to claim 1, further comprising the step of: (c) post-treating the formed object. ### Claim 6 A formulation for three-dimensional printing comprising: (i) 60 wt % to 95 wt % liquefied polymer resin; (ii) 5 wt % to 40 wt % particles; (iii) 0.1 wt % to 5 wt % photoinitiator; and (iv) 0 to 0.2 wt % photoadditive, based on the weight of the formulation; wherein said particles comprise a plurality of particles having various density values; and wherein said particles have densities in a range of 3 g/cm3 to 12 g/cm3. ### Claim 7 (depends on 6) The formulation according to claim 6, wherein said particles have a particle size in a range of 50 nm to 50 microns. ### Claim 8 (depends on 6) The formulation according to claim 6, wherein said particles have a shape that is selected from the group consisting of spheres, rods, fibers, plates, and star-shaped. ### Claim 9 (depends on 6) The formulation according to claim 6, wherein said liquefied polymer resin comprises an acrylate. ### Claim 10 (depends on 9) The formulation according to claim 9, wherein said acrylate is a monomer or oligomer selected from the group consisting of bisphenol A dimethacrylate (Bis-DMA), bisphenol A diglycidyl ether methacrylate (Bis-GMA), ethoxylated bisphenol-A dimethacrylate (Bis-EMA), Tricyclo[5.2.1.02,6]decanedimethanol diacrylate, Bisphenol A glycerolate diacrylate, Bisphenol A ethoxylate diacrylate, Bisphenol A ethoxylate dimethacrylate (oligo), Bisphenol F ethoxylate diacrylate (oligo), Poly(ethylene glycol) diacrylate, Di(ethylene glycol) diacrylate, Tetra(ethylene glycol) diacrylate, 1,4-Butanediol diacrylate, Hydroxy ethylmethacrylate, 3,4-epoxy-cyclohexyl-methyl methacrylate (METHB), triethylene glycol dimethacrylate (TEGDMA), Tertiobutyl cyclohexanol methacrylate, 1,6-bis[2-(methacryloyloxy) ethoxycarbonylamino]-2,4,4-trimethylhexane (UDMA), 3,3,5-trimethyl cyclohexanol methacrylate, Dipentaerythritol penta-/hexa-acrylate, and mixtures thereof. ### Claim 11 (depends on 6) The formulation according to claim 6, wherein said particles are selected from the group consisting of metal oxides, metal nitrides, metal carbides, metalloid oxides, metalloid nitrides, and metalloid carbides. ### Claim 12 (depends on 11) The formulation according to claim 11, wherein the metal or metalloid of said metal oxides, metal nitrides, metal carbides, metalloid oxides, metalloid nitrides, or metalloid carbides is selected from the group consisting of Group 2, Group 3, Group 4, Group 5, Group 6, Group 8, Group 11, Group 12, Group 13, Group 14, and the lanthanide series of the Periodic Table of Elements. ### Claim 13 (depends on 12) The formulation according to claim 12, wherein said particles are selected from the group consisting of zinc oxide, Silicon carbide, Silicon nitride, Gallium nitride, Aluminium oxide, Titanium dioxide, Zirconium dioxide, Tin dioxide, Iron (III) oxide, Magnesium oxide, Indium (III) oxide, Tungsten trioxide, Tungsten (IV) oxide, Silver oxide, Vanadium (V) oxide, Vanadium (IV) oxide, Molybdenum trioxide, Yttrium (III) oxide, Cerium (IV) oxide, and Copper (II) oxide. ### Claim 14 (depends on 6) The formulation according to claim 6, wherein said photoinitiator is a type I or type II photoinitiator. ### Claim 15 (depends on 14) The formulation according to claim 14, wherein said photoinitiator is selected from the group consisting of bis(2,4, 6-trimethyl benzoyl)phenylphosphine oxide (IRGACURE 819), Phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO), 2,4,6-trimethylbenzoyl diphenyl phosphine (TPO), 2-hydroxy-2-methyl-1-phenyl-1-propane (DAROCUR 1173), and benzophenone (BP). ### Claim 16 (depends on 6) The formulation according to claim 6, wherein said photoadditive is a photoabsorber selected from the group consisting of Sudan I-IV, 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene, 4-methoxyphenol, and butylated hyrdorxytoluene. ### Claim 17 (depends on 6) A three-dimensional printed object having a varying degree of transmissivity to light along an axis of said object; wherein along said axis, a transparency of said object varies gradationally from opaque or partially opaque on one end to translucent or transparent on an opposite end; and wherein said object is formed from the formulation according to claim 6.