权利要求：
1. A process for 3D printing a 3-dimensional (3D) object, the process comprising:
a) providing a suspension comprising:
60-95% by weight of the total suspension (w/w) of at least one polymeric material and/or metallic material; and
at least 10% by weight of the total suspension (w/w) of one or more fatty acids or derivatives thereof; and
b) 3D printing the desired object using the suspension as a feedstock;
wherein said fatty acid derivatives comprises at least one acid group from the group consisting of carboxylic acid, phosphonic acid and sulfonic acid group attached to at least one C5-C30 hydrocarbon.
2. The process according to claim 1, comprising at least one polymeric material.
3. The process according to claim 1, wherein the polymer material is selected from the group consisting of polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA), polystyrene (PS), polyethylene (PE), polypropylene (PP), polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(1,4-phenylene sulfide) (PPS), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), polyamide (PA), polybutylene terephthalate (PBT), polyetheretherketone (PEEK), polyetherketone (PEK), polyethylene terephthalate (PET), polyimide (PI), polyoxymethylene (POM), polysulfone (PSU), polyurethane (PU), polybutadiene (PB), polytetrafluoroethyelen (PTFE), polyvinylfluoride (PVF), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene-propylene (FEP), polyethylenetetrafluoroethylene (ETFE), polyethylenechlorotrifluoroethylene (ECTFE), polyethylene glycol (PEG), polyhydroxyalkanoates (PHA), polyhydroxyvalerate (PHV), polyhydroxybutyrate (PHB), liquid crystal polymer, polyacrylate, polyacetals, polyamideimide (PAI), polybutylene(PB), polyvinylchloride (PVC), acrylonitrile butadiene styrene (ABS), polyphenylsulfone (PPSU), polymethylpentane (PMP), alginate, chitin, chitosan, acrylic acid, hyaluronic acid, starch, amylose, amylopectin, pectin, dextran, pullulan, gum arabic, xanthan gum, pullulan, cellulose, polysaccharides, proteins, nucleic acids, rubber, silicone and co-polymers thereof.
4. The process according to claim 1, comprising at least one metallic material.
5. The process according to claim 1, wherein the metallic material is selected from the group consisting of copper, zinc, aluminium, iron, silver, gold, palladium, platinum, tin, antimony, bismuth, lead, nickel, cobalt, vanadium, manganese, chromium, titanium, tantalum, tungsten, neodymium, lithium, sodium, osmium, iridium, uranium, thorium, plutonium, yttrium, zirconium, niobium, molybdenum, rhodium, cadmium, hafnium, rhenium, mercury, gallium, indium, thallium, lanthanum, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, potassium, calcium, magnesium, strontium, barium, germanium, arsenic, astatine and alloys and hydrides thereof.
6. The process according to claim 1, wherein the suspension comprises:
60-90% by weight of the total suspension (w/w) of at least one polymeric material and/or metallic material; and
at least 10% by weight of the total suspension (w/w) of one or more fatty acids.
7. The process according to claim 1, wherein the suspension further comprises one or more hydrophilic polymer components.
8. The process according to claim 1, comprising in the range 60-95% of the at least one metallic material, by weight of the total suspension (w/w).
9. The process according to claim 1, wherein the one or more fatty acids are selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid.
10. The process according to claim 1, wherein the suspension comprises in the range 5-50% fatty acid by weight of the total suspension.
11. The process according to claim 1, wherein the polymer and/or metal material is biodegradable.
12. The process according to claim 1, wherein the polymer and/or metal material is biocompatible.
13. The process according to claim 1, wherein one or more drugs are added before or after 3D printing.
14. The process according to claim 1, wherein the object is a medical implant.
15. The process according to claim 1, wherein the suspension comprises a mixture of 70-92% (w/w) metal material and 8-30% (w/w) fatty acid.
16. The process according to claim 1, wherein the suspension does not comprise a component selected from the group consisting of paraffin, alkanes, waxes, mineral oils, petroleum jelly, polypropylene, polyethylene and polymers that undergo no or limited degradation and/or resorption in the human body.
17. The process according to claim 1, wherein the 3D printing process is selected from the group consisting of robocasting, direct ink writing, ink jet printing, binder jetting, selective heat sintering, selective laser sintering, selective laser melting, stereolithography, filament printing, pellet printing, powder printing, freeform fabrication, rapid prototyping or deposition from a robotic arm.
18. The process according to claim 1, comprising a step c) of solidifying the printed material by a method selected from the group consisting of sintering, hydrating, coating, melting, infiltrating and/or crosslinking the 3D printed material.
19. The process according to claim 1, wherein the particle size of the one or more materials are in the range 1 nm to 1 mm.
20. The process according to claim 1, wherein the suspension comprises less than 1% by weight water.
具体实施方式：
[0054]The present invention will now be described in more detail in the following.
DETAILED DESCRIPTION OF THE INVENTION
Suspension
[0055]As discussed above, the present invention relates in particular to a suspension having superior properties in 3D printing or extrusion processes. Thus, in an aspect the invention relates to a suspension comprising[0056]50-95% by weight of the total suspension (w/w) of at least one metallic material and/or ceramic material and/or polymeric material and/or solid carbon containing material; and[0057]at least 3% by weight of the total suspension of one or more fatty acids or derivatives thereof, preferably saturated fatty acids, preferably at least 4%, and even more preferably at least 5%.
[0058]It is of course to be understood that the at least one metallic material and/or ceramic material and/or polymeric material and/or carbon containing material is suspended in the suspension. Thus, these materials are solids in the suspension.
[0059]As shown in e.g. example 1, other liquids are not able to support the same level of solids in a suspension during e.g. a 3D-printing process comprising ceramics. Example 3 shows the same effect of a composition comprising metal, exemplified by copper. Thus, in a more specific embodiment the suspension is for use as a feedstock for 3D printers or extruders. In the present context, the terms “feedstock” and “ink” may be used interchangeably. The terms relate to the material used in a 3D printing process, i.e. the material being printed.
Fatty Acids
[0060]In the present context, a fatty acid or derivative thereof is to be understood as one or more free carboxylic, sulfonic or phosphonic acid, attached to one or more hydrophobic hydrocarbon, which is either aliphatic or aromatic or possibly a mixture thereof. A large range of natural fatty acids exist, which are typically carboxylic acids attached to saturated or unsaturated alkyl groups, which may be unbranched (i.e. linear) or branched. Other synthetic or natural amphiphiles may also be used, which could include acids attached to for example aromatic and/or cyclic aliphatic groups.
[0061]In an embodiment of the invention, the term “fatty acid” acid includes free fatty acids. Free fatty acids are usually derived from triglycerides or phospholipids. When they are not attached to other molecules, they are known as “free” fatty acids.
[0062]In another embodiment, the one or more fatty acids or derivative thereof comprises at least one acid group from the group consisting of carboxylic acid, phosphonic acid and sulfonic acid group attached to at least one C5-C30 hydrocarbon.
[0063]In yet an embodiment, the hydrocarbon is a saturated or unsaturated aliphatic hydrocarbon group or an aromatic hydrocarbon group or a mixture thereof.
[0064]In a further embodiment, the fatty acid comprises at least one carboxylic acid and the hydrocarbon is a saturated or unsaturated C5-C30 aliphatic hydrocarbon group.
[0065]In yet an further embodiment, the fatty acid or derivative thereof is a compound of Formula (I):
[0066]
wherein
R is a saturated or unsaturated C5-C30 aliphatic hydrocarbon group,
Z is selected from the group consisting of carbon (C), S(O), and P(OH).
[0067]In a preferred embodiment, Z is carbon (C). In another preferred embodiment the saturated or unsaturated C5-C30 aliphatic hydrocarbon group is unbranched.
[0068]In yet an embodiment, the saturated or unsaturated C5-C30 aliphatic hydrocarbon group is branched. In yet a further embodiment the saturated or unsaturated aliphatic hydrocarbon group is a C6-C30 aliphatic hydrocarbon group, such as a C7-C30, C8-C30, C9-C30, C10-C30, C10-C25, C10-C20 aliphatic hydrocarbon group.
Material
[0069]In an embodiment of the invention, the term “material” relates to a solid material or a powder of the material. It is of course to be understood that the material of the suspension is predominantly in a suspended form in the suspension. The material in the suspension is also in a form with a particle size to keep it predominantly in the suspension, such as by having a particle size in the range 1 nm-1 mm. The precise particle size may vary dependent on the material.
Metallic Material
[0070]When it comes to printing of metallic material, different metals may form part of the suspension. Thus, in an embodiment, the metallic material is selected from the group consisting of copper, zinc, aluminium, iron, silver, gold, palladium, platinum, tin, antimony, bismuth, lead, nickel, cobalt, vanadium, manganese, chromium, titanium, tantalum, tungsten, neodymium, lithium, sodium, osmium, iridium, uranium, thorium, plutonium, yttrium, zirconium, niobium, molybdenum, rhodium, cadmium, hafnium, rhenium, mercury, gallium, indium, thallium, lanthanum, cerium, praseodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, potassium, calcium, magnesium, strontium, barium, germanium, arsenic, astatine and alloys and hydrides thereof. In example 3, copper is printed, in example 6 silver is printed and in example 7 copper and steel are printed.
Printing of Ceramic Material
[0071]In the present context, “ceramic materials” are inorganic, non-metallic materials made from compounds of a metal and a non-metal. When it comes to printing of ceramic material, different ceramics may form part of the suspension. Thus, in an embodiment, the ceramic material is selected from the group consisting of TCP (tricalciumphosphate), MCP (monocalciumphosphate), DCP (dicalciumphosphate), tetracalciumphosphate, hydroxylapatite, alpha-TCP, beta-TCP, titanium oxide (titania), aluminium oxide (alumina), zirconium oxide (zirconia), yttrium oxide (yttria), yttria stabilized zirconia, indium oxide, indium tin oxide, boron nitride, silicon carbide, boron carbide, tungsten carbide, beryllium oxide, zeolite, cerium oxide (ceria), tungsten disilicide, sodium silicide, platinium silicide, zirconium nitride, tungsten nitride, vanadium nitride, tantalum nitride, niobium nitride, silicon boride, clay, earth, soil, cement, portland cement, silica, barium titanate, lead zirconate titanium, zinc oxide, potassium niobate, lithium niobate, sodium tungstate, glass, geopolymers, sodium chloride, sodium nitrate, potassium nitrate, potassium chloride, magnesium chloride, calcium chloride, calcium nitrate, magnesium nitrate, strontium oxide, strontium phosphate, calcium sulfate, barium sulfate, calcium carbonate, sodium carbonate, sodium fluoride and mixtures thereof. In examples 1 and 2, different ceramics are printed in suspensions according to the invention.
Printing of Polymer Material
[0072]When it comes to printing of polymer material, different polymers may form part of the suspension. Thus, in an embodiment, the polymer material is selected from the group consisting of polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA), polystyrene (PS), polyethylene (PE), polypropylene (PP), polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(1,4-phenylene sulfide) (PPS), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), polyamide (PA), polybutylene terephthalate (PBT), polyetheretherketone (PEEK), polyetherketone (PEK), polyethylene terephthalate (PET), polyimide (PI), polyoxymethylene (POM), polysulfone (PSU), polyurethane (PU), polybutadiene (PB), polytetrafluoroethyelen (PTFE), polyvinylfluoride (PVF), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene-propylene (FEP), polyethylenetetrafluoroethylene (ETFE), polyethylenechlorotrifluoroethylene (ECTFE), polyethylene glycol (PEG), polyhydroxyalkanoates (PHA), polyhydroxyvalerate (PHV), polyhydroxybutyrate (PHB), liquid crystal polymer, polyacrylate, polyacetals, polyamideimide (PAI), polybutylene (PB), polyvinylchloride (PVC), acrylonitrile butadiene styrene (ABS), polyphenylsulfone (PPSU), polymethylpentane (PMP), alginate, chitin, chitosan, acrylic acid, hyaluronic acid, starch, amylose, amylopectin, pectin, dextran, pullulan, gum arabic, xanthan gum, pullulan, cellulose, elastin, collagen, gelatin, fibronectin, silk, polysaccharides, proteins, nucleic acids, rubber, silicone and co-polymers thereof.
Printing of Carbon Containing Material
[0073]When it comes to printing of carbon containing material, different molecules may form part of the suspension. Thus, in an embodiment, the carbon containing material is selected from the group consisting of: Graphite, graphene, carbon nanotubes, other allotropes of carbon, glucose, sucrose, citric acid, oxalic acid, penicillin, tetracycline, other antibiotics, analgesics, pain killers, vitamins, steroids, hormones, chemotherapy, other drugs and pharmaceutics, and mixtures thereof, as well as complex natural compositions such as bone matrix, dehydrated bone matrix and decellularized bone matrix derived from humans, animals, cell culture or any other living organism. Example 6 shows printing of graphite.
[0074]The particle size of the one or more materials may vary. Thus, in an embodiment, the particle size of the one or more materials are in the range 1 nm-1 mm, such as below 500 μm, below 354 μm, below 250 μm, below 149 μm, below 105 μm, below 74 μm, below 44 μm, below 10 μm, below 1 μm, below 500 nm, or below 100 nm, preferably below 10 μm. It is well known that the particle size may also be determined by the mesh size used to determine the upper limit of the particles. For example, a mesh 200 corresponds to a cut-off of 74 μm. In the example section materials which sizes from 0.5 micrometer up to around 44 micrometer have been tested.
[0075]Without being bound by theory it is believed that particles below 10 μm will work the best (thus a preferred embodiment). Alternatively a mixture of particles having particles in the range 1-10 micrometer and particles in the range 100 nm to 1 micrometer is preferred (another preferred embodiment). Such mixture of particles sizes gives in theory the best packinging and this may lead to a higher density of the printed material.
[0076]The amount of metallic and/or ceramic material may also be further defined. Thus, in an embodiment, the suspension comprises in the range 60-95% of the at least one metallic or ceramic material (or polymer), by weight of the total suspension (w/w), such as 60-95%, such as 70-95%, such as 77-95%, such as 80-95%, such as 85-95%, such as 90-95%, such as 80-85%, such as 80-84%, such as 80-83%, such as 80-82%, such as 81-85, such as 82-85%, or such as such as 83-85%. As shown in the example section, the optimal concentration can be determined for different materials.
[0077]Different fatty acids may form part of the present invention. Thus, in an embodiment, the one or more fatty acids are selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. In the example section different fatty acids have been verified to comply with the present invention.
[0078]Similar, the concentration of fatty acid may also be optimized. Thus, in an embodiment, the suspension comprises in the range 5-50% fatty acid by weight of the total suspension, such as in the range 4-50%, such as in the range 5-50%, such as in the range 10-50%, such as in the range 10-40%, such as 10-30% such as 12-30%, such as 15-30%, such as 15-20%, such as 15-18% or such as 15-17%.
[0079]The combination of ceramic and fatty acid may also be optimized. Thus, in an embodiment, the suspension comprises a mixture of 80-85% (w/w) ceramic material and 15-20% (w/w) (free) fatty acid, such as a mixture of 80-85% (w/w) TCP and 15-20% (w/w) oleic acid; or a mixture of 80-85% (w/w) TCP and 15-20% (w/w) linoleic acid; or a mixture of 80-85% (w/w) TCP and 15-20% (w/w) steric acid.
[0080]In yet an embodiment, the suspension comprises a mixture of 70-90% (w/w) ceramic material and 10-30% (w/w) (free) fatty acid, such as a mixture of 70-90% (w/w) TCP and 10-30% (w/w) oleic acid; or a mixture of 70-90% (w/w) TCP and 10-30% (w/w) linoleic acid; or a mixture of 70-90% (w/w) TCP and 10-30% (w/w) steric acid. Examples of such compositions can be found in e.g. example 2.
[0081]In yet an embodiment the suspension comprises a mixture of 70-92% (w/w) metal material and 8-30% (w/w) (free) fatty acid, such as a mixture of 70-92% (w/w) copper and 8-30% (w/w) oleic acid; or a mixture of 70-92% (w/w) copper and/or silver and 8-30% (w/w) linoleic acid; or a mixture of 70-92% (w/w) steel and 8-30% (w/w) steric acid. Examples of such compositions can be found in e.g. examples 3, 6 and 7.
[0082]In yet an embodiment the suspension comprises a mixture of 50-80% (w/w) carbon-containing material and 20-50% (w/w) (free) fatty acid, such as a mixture of 50-80% (w/w) graphite or graphene powder and 20-50% (w/w) (free) fatty acid; or a mixture of 50-80% (w/w) graphite and 20-50% (w/w) stearic acid. Examples of such compositions can be found in e.g. example 6.
[0083]Examples of preferred compositions which may find use in the processes and uses according to the present invention are listed below.
[0084]80-95% TCP with 20-5% of fatty acid that has a melting point above 37° C. Such composition may after printing (resulting material) find use as a bone or dental implant with or without prior sintering.
[0085]80-95% Hydroxyl apatite with 20-5% of fatty acid that has a melting point above 37° C. Such composition may after printing (resulting material) find use as a bone or dental implant with or without prior sintering.
[0086]80-95% biphasic TCP/hydroxylapatite with 20-5% of fatty acid that has a melting point above 37° C. Such composition may after printing (resulting material) find use as a bone or dental implant with or without prior sintering.
[0087]80-95% of a stoichiometric powder mixture of TCP and MCP with 20-5% of fatty acid that has a melting point above 37° C. Such composition may after printing (resulting material) find use as a bone or dental implant with or without prior sintering or cementing.
[0088]80-95% of a stoichiometric powder mixture of tetracalcium phosphate and dicalciumphosphate with 20-5% of fatty acid that has a melting point above 37° C. Such composition may after printing (resulting material) find use as a bone or dental implant with or without prior sintering or cementing.
[0089]In the above listed preferred embodiments one or more protein or carbohydrate extracellular matrix components or derivatives thereof, may be added to improve mechanical strength and/or cell adhesion and/or tissue formation. This could be collagen, gelatin, hyaluronic acid, elastin or fibronectin.
[0090]Further, in the above preferred embodiments one or more components, may be added to improve the binding between the calcium phosphate and the extracellular matrix component. This could be osteopontin, bone sialoprotein orbone acidic glycoprotein-75.
[0091]In an embodiment the material produced according to the invention, may be made from a suspension that dissolves in the human body and which leaves a hydrogel after dissolution and which is used as an implant for generating soft tissues such as cartilage, tendons, ligaments, vasculature, skin, adipose tissue or components of nervous tissue or of the internal organs. This could be a suspension comprising 5-30% fatty acid and 0.1%-95% of a solid particulate that may form a hydrogel, this could be an extracellular matrix component or derivative thereof e.g. collagen and gelatin. Such as suspension may also be added 1-94.9% of a carbon containing molecule to aid with dissolution, this could be carbohydrates, amino acids or other organic compounds that are solubilized in humans.
[0092]In yet an embodiment the 3D printed or extruded material is used as a non-sintered implant and an amphiphile component is added before, during or after 3D printing or extrusion to coat the material to make it more hydrophilic. This could for example be short or medium chain free fatty acids or aminoacids with hydrophobic sidechains.
[0093]In yet a further embodiment one or more drugs are added before or after 3D printing. This could for example be a natural protein such as a BMP, PDGF, HGF, IGF, NGF, BDNF, GDNF, VEGF, LIF or insulin, it could also be a plasmid DNA, viral DNA, viral RNA, small interfering RNA (siRNA), microRNA (miRNA), messenger RNA (mRNA), a CRISPR based nucleic acid editing system, a vitamin such as vitamin D, Vitamin C, Vitamin A, vitamin E or Vitamin K, a synthetic drug such as dexamethasone or H8, an anti-cancer drug such as doxorubicin, an anti-inflammatory and/or analgesic compound such as an NSAID drug or an antibiotic such as a penicillin, a tetracyclin, a quinolone, a macrolide, a cephalosporin, a carbapenem, an aminoglycoside or a glyco- or lipopeptide.
[0094]In yet an further embodiment the solid particulates are pharmaceuticals and the resulting material is used as an implantable drug depot with the aim of controlling drug release kinetics. In a similar embodiment the solid particulates are pharmaceuticals where they are mixed with excipients and/or carbohydrates and/or drug delivery systems and where the resulting material is used as an implantable drug depot with the aim of controlling drug release kinetics.
[0095]In yet an embodiment the suspension is a mixture of one or more metals, one or more ceramic powders, and a fatty acid, where the aim is to create a cermet or a metal matrix composite material. Such as a mixture may be between calcium salts and/or silica and/or alumina with copper and/or a copper alloy and/or steel.
[0096]In an embodiment the suspension comprises a fatty acid and one or more electrically conductive materials such as silver, copper, graphite, graphene or carbon nanotubes. Such compositions may be used for creating an electrically conductive and/or anti-static and/or electromagnetic shielding and/or sensor and/or electrode object.
[0097]In yet an embodiment the suspension comprises an unsaturated fatty acid, where the unsaturated fatty acid's double or triple bonds are crosslinked or reacted with other components during or after 3D printing or extrusion with the aim of mechanically stabilizing the printed object.
[0098]In a more specific embodiment, the suspension consists of the metallic, and/or ceramic, and/or polymeric material and fatty acid. In another embodiment, the suspension is free from Plasticine and/or modelling clay.
[0099]In another embodiment, the suspension according to the invention, comprises at least 80% solid material and 5-20% fatty acid, preferably at least 80% solid material where the remainder is at least 50% fatty acid, such as 75% fatty acid, such as 90% fatty acid, such as, or 99% fatty acid, or the remainder is 100% fatty acid.
[0100]In certain cases, it may be preferred that the suspension is free or substantially free from water. Thus, in an embodiment, the suspension comprises less than 1% by weight water, preferably, the suspension is non-aqueous.
[0101]The suspension may also be non-newtonic. Thus, in an embodiment the suspension is non-newtonic or a Bingham plastic.
[0102]For medical equipment it is of course important that the body can tolerate the generated material. Thus, in an embodiment, the ceramic, polymer and/or metal is biocompatible. In another embodiment, the ceramic, polymer and/or metal is biodegradable. In yet an embodiment, the biodegradable material is selected from the group consisting of calcium phosphates, calcium sulfates, PCL, PLA, PGA, PHB, PHV, PHA or co-polymers thereof as well as alloys of magnesium and/or iron and/or calcium. Example 5 shows biocompability tests in mice using TCP.
[0103]To avoid evaporation, it may be beneficial that the vapour pressure of the fatty acid at room temperature (25° C.) is not too high. Thus, in an embodiment, the fatty acid has a vapour pressure at room temperature of no more than 17.5 mmHg.
[0104]It is of course to be understood that the suspension may comprise more than one solid material. Thus, in an embodiment, the suspension comprises two or more metallic materials and/or two or more ceramic materials and/or two or more polymeric materials or mixtures thereof.
[0105]The (free) fatty acid may be generated in different ways. Thus, in an embodiment, the suspension comprises completely or partially hydrolysed triglycerides and/or phospholipids, wherein the suspension may contain one or more fatty acids with or without glycerol or glycerol conjugated compounds.
[0106]The suspension may also comprise other constituents. Thus, in an embodiment, the suspension further comprises one or more of water, polymers, emulsifiers, solvents, binders, cross-linkers, surfactants, viscosity modifiers, anti-oxidants, anti-microbial compounds, dispersants, plasticizers, flocculants, polycarboxylates, polyacids, polybases, chromophores, pigments, soaps, glycerol, phospholipids, alkanes, alcohols, ethers, aldehydes, ketones, esters, amines and thiols, phosphates, sulfates, sulfonic acids and superplasticizers.
Use of Suspension
[0107]As described above and in the example section, the suspension according to the present invention, is especially suited in 3D printing processes. Thus, an aspect of the invention relates to the use of a suspension according to the invention in a 3D printing or extrusion process, preferably a 3D printing process. Phrased in another way, in yet an aspect the invention relates to the use of a suspension according to the invention, as a feedstock, an ink, a deposited material or an extruded material for a 3D printer or an extruder.
[0108]In another aspect the invention relates to the use of a suspension comprising[0109]50-95% by weight of the total suspension (w/w) of at least one ceramic material; and/or metallic material and/or polymeric material and/or carbon containing material, such as graphite; and[0110]at least 5% by weight of the total suspension (w/w) of one or more fatty acids or derivatives thereof;
in a 3D printing or extrusion process.
[0111]As also outlined above, the suspension according to the invention has several advantages in e.g. 3D printing processes. Thus, in an embodiment, the use is for avoiding precipitation and/or cementation of the feedstock/ink prior and/or during and/or after printing or extrusion. In a further embodiment, the use is for avoiding oxidation of metal material during sintering, with the proviso that the suspension comprises metal material. In another embodiment, the use is for improving the tolerance of the object, its form and shape retention and its mechanical strength prior to post-printing processing. This is achieved by printing the suspension at a temperature above the melting point of one or more of its constituent fatty acids onto a stage or object with a temperature that is lower than the melting point of one or more of its constituent fatty acids so that it freezes and stiffens after deposition. In yet an embodiment, the use is for increasing the tensile strength and/or flexural strength and/or compressive strength and/or shear strength of the 3D printed or extruded object. As shown in example 1, a particular high content of solid material can be printed with the suspension according to the invention. Such high content increases the strength of the printed material. In yet an embodiment, the suspension is for increasing the density of the 3D printed or extruded material. In yet an embodiment, the suspension is for increasing the biocompatibility of the 3D printed or extruded material.
[0112]The data provided in Example 1, indicates that the material printed with the suspension according to the present invention has a high biocompatibility. Thus, in an embodiment, the suspension is for increasing the biocompatibility of the 3D printed or extruded material.
[0113]The 3D printing process may be selected from different technologies. Thus, in an embodiment, the 3D printing process is selected from the group consisting of robocasting, direct ink writing, ink jet printing, binder jetting, selective heat sintering, selective laser sintering, selective laser melting, stereolithography, filament printing, pellet printing, material printing, freeform fabrication, rapid prototyping and deposition from a robotic arm.
Process for 3D Printing or Extruding a 3-Dimensional (3D) Object
[0114]The present invention also relates to a process for producing a 3D object using the suspension according to the invention. Thus, in an aspect the invention relates to a process for 3D printing or extruding a 3-dimensional (3D) object, the process comprising[0115]a) providing a suspension according to the invention;[0116]b) 3D printing or extruding the object using the suspension as a feedstock; and[0117]c) optionally, solidifying the printed or extruded material, e.g. by a method selected from the group consisting of sintering, hydrating, coating, melting, infiltrating, freezing, crystallizing, precipitating and/or crosslinking the 3D printed or extruded material.
[0118]In a further aspect the invention relates to a process for 3D printing or extruding a 3-dimensional (3D) object, the process comprising[0119]a) providing a suspension comprising[0120]50-95% by weight of the total suspension (w/w) of at least one ceramic material; and/or metallic material and/or polymeric material and/or carbon containing material, such as graphite; and[0121]at least 5% by weight of the total suspension (w/w) of one or more fatty acids or derivatives thereof.[0122]b) 3D printing or extruding the desired object using the suspension as a feedstock; and[0123]c) optionally, solidifying the printed or extruded material by a method selected from the group consisting of sintering, hydrating, coating, melting, infiltrating and/or crosslinking the 3D printed or extruded material. Preferably a sintering step is included.
[0124]As shown in the example 1, the 3D printed objects, formulated with fatty acid based suspensions, have superior properties compared to other 3D printed materials, such as a higher compressive strength and better biocompatibility. It is to be understood that the printed object may be a composite material comprising several (different) printed materials. Such composite material may be generated by printing simultaneously from different printing nozzles, or by a stepwise procedure, with or without an intermediate solidification step such as sintering.
[0125]The nozzle size of a printer/extruder may determine how precise an object can be generated. Thus, in an embodiment said 3D printing takes place through one or more nozzles, wherein the area of the orifice of each nozzle is in the range 10 μm2 to 2000 μm2, such as 50-2000 μm2, such as 50-1000 μm2, such as 50-500 μm2.
[0126]Sintering of a generated object may take place at different temperatures depending on the material. Thus, in yet an embodiment said sintering takes place by heating the entire object to a temperature in the range 150 to 3000° C., such as in the range 250 to 350° C., such as in the range 300 to 400° C., such as in the range 400 to 500° C., such as in the range 600 to 700° C., such as in the range 900 to 1000° C., such as in the range 1000 to 1200° C., such as in the range 1200 to 1400° C., such as in the range 1400 to 1700° C., or such as in the range 1700 to 2500° C.
[0127]In yet a different embodiment, the sintering process takes place in two steps, the first to carbonize the fatty acid and the second to oxidize the carbon and sinter the particles. This could e.g. be 1 hour at 400° C. and 2 hours at 1100° C. in the case of stearic acid and TCP.
[0128]In yet another embodiment, the sintering process takes place under atmospheric pressure or under partial vacuum. Ovens that operate at atmospheric pressure are simpler and cheaper, whereas ovens that operate at partial vacuum may reduce oxidation of the 3d printed object and help with the removal of fatty acids through evaporation or sublimation.
[0129]In a further embodiment, the sintering process takes place in atmospheric air. Ovens that operate with atmospheric air are simpler and cheaper.
[0130]In another embodiment, the sintering process takes place in air comprising more than 80% argon and/or nitrogen. Ovens that operate with protective gasses may reduce oxidation of the 3D printed object.
[0131]The printed objects may also have a substantial size. Thus, in a further embodiment, the 3D printed or extruded 3-dimensional object has a volume of at least 1 cm3, such as at least 10 cm3, such as in the range 1-1000 cm3 or such as 1-100 cm3.
[0132]The generated objects may be for medical purposes. Thus, in an embodiment, the object is a medical implant, such as a bone or dental implant. Example 4 describes printing of bone implants.
[0133]The printed objects comprising metal, may be particular relevant within certain industrial fields. Thus, in an embodiment, the 3D printed or extruded 3-dimensional object comprises metal and is selected from the group consisting of whole items, parts or components of medical devices, medical implants, electronics, power electronics, robots, machinery, turbines, tubes, fittings, armour, weapon systems, cars, motorcycles, bicycles, aircraft, spacecraft, ships, submarines, oil platforms, mining equipment, wind turbines, offshore installations, armoured vehicles, tanks, heterogeneous chemical catalysts, engines, tanks, containers, drilling equipment, buildings, power plants, art, jewellery, household items and toys.
[0134]The printed objects comprising ceramics, may also be particular relevant within certain industrial fields. Thus, in an embodiment the 3D printed or extruded 3-dimensional object comprises ceramics and is selected from the group consisting of whole items, parts or components of medical devices, medical implants, tooth or bone replacement materials, thermal insulation, electric insulation, acoustic insulation, armour, weapon systems, refractory materials, engines, power plants, electronics, turbines, wind turbines, heterogeneous chemical catalysts, buildings, bridges, roads, dams, infrastructure, art and pottery.
[0135]The temperature during printing may also vary. Thus, in yet an embodiment, step b) is carried out at a temperature in the range 10-30° C., such as 15-25° C., or in the range of 30-100° C., such as 40-80° C., such as 50-70° C., or such as 60-70° C.
[0136]It is to be understood that this temperature relates to the temperature of the suspension before and/or during 3d printing or extrusion and that the temperature immediately after deposition such as on the stage or platform may be lower, the same or higher.
[0137]The temperatures below 30° C. may be relevant for fatty acids (or the suspension is general) being liquid at that temperature range. On the other hand temperatures in the range 30-100° C. may be relevant if a suspension is used, which have a melting temperature in that range. If such material is printed into a cooled environment, the material will solidify after printing extrusion. Examples of fatty acids having a melting temperature in the temperature range 30-100° C. are decanoic acid (capric acid), dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), eicosanoic acid (arachidic acid), docosanoic acid (behenic acid), tetracosanoic acid (lignoceric acid).
3-Dimensional Object Obtained/Obtainable by the Process
[0138]In yet another aspect, the invention relates to a 3D printed or extruded 3-dimensional object obtained/obtainable by a process according to the invention.
Other Aspects of the Invention
[0139]The present invention may be defined by different product combination.
[0140]In a further aspect, the invention relates to a 3D printer loaded with suspension according to the present invention. It is to be understood that the 3D printer is loaded with the suspension making it possible to 3D print the suspension. Thus, the suspension is loaded as a feedstock.
[0141]In yet an aspect the invention relates to a kit comprising[0142]a 3D printer; and[0143]a suspension according to the invention.
[0144]In yet a further aspect, the invention relates to a kit comprising[0145]a 3D printer; and[0146]instructions for printing a 3D object using the suspension according to the invention as a feedstock.
[0147]In another asp