WO2019139927A1 - Compositions et procédés d'impression 3d utilisant un ester de cellulose - Google Patents

Compositions et procédés d'impression 3d utilisant un ester de cellulose Download PDF

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Publication number
WO2019139927A1
WO2019139927A1 PCT/US2019/012805 US2019012805W WO2019139927A1 WO 2019139927 A1 WO2019139927 A1 WO 2019139927A1 US 2019012805 W US2019012805 W US 2019012805W WO 2019139927 A1 WO2019139927 A1 WO 2019139927A1
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WIPO (PCT)
Prior art keywords
solvent
cellulose
phosphate
printing
printing composition
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PCT/US2019/012805
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English (en)
Inventor
Michael Combs
Christopher BUNDREN
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Acetate International Llc
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Publication of WO2019139927A1 publication Critical patent/WO2019139927A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE 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
    • B29C64/00—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
    • B29C64/10—Processes of additive manufacturing
    • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE 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
    • B29C64/00—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
    • B29C64/10—Processes of additive manufacturing
    • B29C64/106—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
    • B29C64/118—Processes of additive manufacturing using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material using filamentary material being melted, e.g. fused deposition modelling [FDM]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y70/00—Materials specially adapted for additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
    • B29K2001/08—Cellulose derivatives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
    • B29K2001/08—Cellulose derivatives
    • B29K2001/12—Cellulose acetate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • 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
    • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
    • B29K2001/08—Cellulose derivatives
    • B29K2001/14—Cellulose acetate-butyrate

Definitions

  • the present invention relates generally to 3-D printing using a cellulose ester.
  • the present invention relates to compositions comprising a cellulose ester and a solvent and/or a plasticizer, as well as methods of using those compositions to produce a 3-D product using a 3-D printing device.
  • Three-dimensional (3-D) printing is an additive manufacturing technique wherein a printing composition is deposited in layers to build a 3-D component.
  • a polymer melt is extruded into layers that are then solidified, for example, by cross- linking.
  • Cellulose has been used in 3-D printing compositions as a filler for other materials or suspended in a solvent, but the melting point of cellulose is too close to its decomposition temperature for pure cellulose to be a viable 3-D printing medium.
  • Cellulose esters, such as cellulose acetate have been used in place of cellulose in numerous applications such as film forming compositions, wood fillers, molded articles, and inks.
  • the invention relates to a method of producing a 3-D product using 3-D printing, comprising: introducing a 3-D printing composition into a 3-D printing device, wherein the 3-D printing composition comprises a cellulose ester and further comprises a solvent or a plasticizer; and extruding the composition in a plurality of layers to produce a 3-D structure, wherein the method produces a 3-D product.
  • the extruding step may be carried out at a temperature from 40° C to 200° C, e.g., 40° C to 150° C, or 50° C -100° C.
  • the method may further comprise one or more of chemically treating, thermally treating, or polishing the 3-D product.
  • Chemically treating the 3-D product may comprise exposing at least a portion of the 3-D product to an acid, a base, a reducing agent, a Grignard reagent, a trans-esterification reagent, acylation, amidation, etherification, saponification, an amine, or a combination thereof.
  • Chemically treating the 3-D product may comprise exposing at least a portion of the 3-D product to a metal hydroxide, for example sodium or potassium hydroxide.
  • the 3-D printing composition may further comprise a pigment, dye, biocide, antifungal, antimicrobial, antistatic agent, flame retardant, degradation agent, conductivity modifying agent, stabilizing agent, or any combination thereof.
  • the cellulose ester may comprise cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate-propionate, cellulose acetate-butyrate, cellulose propionate-butyrate, cellulose acetate acylate, a combination thereof, or a mixture thereof.
  • the cellulose ester may comprise cellulose acetate comprising a degree of substitution of acetate from 0.05 to 3.
  • the cellulose ester may be present in an amount from 10 to 50 percent by weight of the 3-D printing composition.
  • the method further comprises evaporating the solvent.
  • the evaporating step does not comprise heating.
  • the method may comprise a plurality of alternating extruding and evaporating steps, and further wherein the solvent from an extruded layer is evaporated prior to extruding a subsequent layer.
  • the solvent may have a boiling point of less than 200° C, e.g., less than 150° C, or less than 100° C.
  • the solvent may comprise acetone, methylethyl ketone, methylene chloride, dioxane, dimethyl formamide, dimethyl succinate, dimethyl adipate, dimethyl glutarate, methanol, ethanol, glacial acetic acid, glycol ether ester, dimethyl carbonate, cyclohexanone, ethyl acetate, butyl acetate, or a mixture thereof.
  • the solvent comprises acetone.
  • the plasticizer may comprise triacetin, triethyl citrate, dimethoxy-ethyl phthalate, dimethyl phthalate, diethyl phthalate, methyl phthalyl ethyl glycolate, bis(o-isopropylphenyl) phenyl phosphate, tris- chloroisopropyl phosphate, l,4-butanediol diacetate, diacetate, dipropionate ester of tri ethylene glycol, dibutyrate ester of triethylene glycol, dimethoxyethyl phthalate, triethyl citrate, triacetyl glycerin, acetyl triethyl citrate, dimethyl adipate, dimethyl succinate, propylene carbonate, dimethyl glutarate, or a combination thereof.
  • the plasticizer comprises triacetin.
  • the plasticizer may be present in an amount from 0.01% to 20% by weight of the 3-D printing composition.
  • the 3-D printing composition comprises a plasticizer and does not comprise a solvent.
  • the present invention relates to a composition for use in 3-D printing, the composition comprising cellulose acetate, triacetin, and acetone.
  • the cellulose acetate may comprise a degree of substitution of acetate from 0.05 to 3.
  • the cellulose acetate may be present in an amount from 10 to 50 percent by weight of the 3-D printing composition and the triacetin may be present in an amount from 0.01 to 20% by weight.
  • the composition may further comprise a pigment, dye, biocide, antifungal, antimicrobial, antistatic agent, flame retardant, degradation agent, conductivity modifying agent, stabilizing agent, pest repellant, or any combination thereof.
  • the present invention is directed to providing compositions and methods of 3-D printing using cellulose esters.
  • the compositions for 3-D printing comprise one or more cellulose esters and a solvent and/or a plasticizer.
  • the compositions for 3-D printing comprise one or more cellulose esters, a solvent, and optionally a plasticizer.
  • the compositions for 3-D printing comprise one or more cellulose esters and a plasticizer, but do not comprise a solvent.
  • the methods of 3-D printing comprise introducing a 3- D printing composition described herein into a 3-D printing device, extruding the composition in a plurality of layers to produce a 3-D structure, and if a solvent is present evaporating the solvent to provide a 3-D product.
  • the methods optionally include post-production treatment of the 3-D product, such as chemical treatment, thermal treatment, or mechanical polishing.
  • the present disclosure relates to a 3-D printing composition
  • a cellulose ester may be selected from organic cellulose esters including, but not limited to, cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate-propionate, cellulose acetate-butyrate, cellulose propionate-butyrate, cellulose acetate acylate, cellulose acetate acrylate, combinations thereof, and mixtures thereof.
  • a cellulose ester described herein has a degree of substitution from 0.05 to 3.0.
  • the cellulose ester is cellulose acetate.
  • Cellulose acetate refers to cellulose diacetate
  • Cellulose acetate and other cellulose esters useful in the 3-D printing compositions and methods described herein may be prepared by known processes, including those disclosed in U.S. Patent No. 2,740,776 and in U.S. Publication No. 2013/0096297, the entireties of which are incorporated by reference herein.
  • acetylated cellulose is prepared by reacting cellulose with an acetylating agent in the presence of a suitable acidic catalyst and then de-esterifying.
  • the cellulose may be from a soft wood or from a hardwood.
  • Softwood is a generic term typically used in reference to wood from conifers (i.e., needle-bearing trees from the order Pinales). Softwood-producing trees include pine, spruce, cedar, fir, larch, Douglas-fir, hemlock, cypress, redwood and yew.
  • hardwood is typically used in reference to wood from broad-leaved or angiosperm trees.
  • the terms "softwood” and "hardwood” do not necessarily describe the actual hardness of the wood.
  • hardwood While, on average, hardwood is of higher density and hardness than softwood, there is considerable variation in actual wood hardness in both groups, and some softwood trees can actually produce wood that is harder than wood from hardwood trees.
  • One feature separating hardwoods from softwoods is the presence of pores, or vessels, in hardwood trees, which are absent in softwood trees.
  • softwood On a microscopic level, softwood contains two types of cells, longitudinal wood fibers (or tracheids) and transverse ray cells. In softwood, water transport within the tree is via the tracheids rather than the pores of hardwoods.
  • a hardwood cellulose is preferred for acetylating.
  • Acylating agents can include both carboxylic acid anhydrides (or simply anhydrides) and carboxylic acid halides, particularly carboxylic acid chlorides (or simply acid chlorides).
  • Suitable acid chlorides can include, for example, acetyl chloride, propionyl chloride, butyryl chloride, benzoyl chloride and like acid chlorides.
  • Suitable anhydrides can include, for example, acetic anhydride, propionic anhydride, butyric anhydride, benzoic anhydride and like anhydrides. Mixtures of these anhydrides or other acylating agents can also be used in order to introduce differing acyl groups to the cellulose.
  • Mixed anhydrides such as, for example, acetic propionic anhydride, acetic butyric anhydride and the like can also be used for this purpose in some embodiments
  • the cellulose is exhaustively acetylated with the acetylating agent to produce a derivatized cellulose having a high DS value, such as from 2.5 to 3, e.g., about 3, along with some additional hydroxyl group substitution (e.g., sulfate esters) in some cases.
  • a high DS value such as from 2.5 to 3, e.g., about 3, along with some additional hydroxyl group substitution (e.g., sulfate esters) in some cases.
  • Exhaustively acetylating the cellulose refers to an acetylation reaction that is driven toward completion such that as many hydroxyl groups as possible in cellulose undergo an acetylation reaction.
  • Suitable acidic catalysts for promoting the acetylation of cellulose often contain sulfuric acid or a mixture of sulfuric acid and at least one other acid. Other acidic catalysts not containing sulfuric acid can similarly be used to promote the acetylation reaction. In the case of sulfuric acid, at least some of the hydroxyl groups in the cellulose can become initially functionalized as sulfate esters during the acetylation reaction. Once exhaustively acetylated, the cellulose is then subjected to a controlled partial de-esterification step, generally in the presence of a de- esterification agent, also referred to as a controlled partial hydrolysis step.
  • a controlled partial de-esterification step generally in the presence of a de- esterification agent, also referred to as a controlled partial hydrolysis step.
  • De-esterification refers a chemical reaction during which one or more of the ester groups of the intermediate cellulosic ester are cleaved from the cellulose acetate and replaced with a hydroxyl group, resulting in a cellulose acetate product having a (second) DS of less than 3.
  • “De-esterifying agent,” as used herein, refers to a chemical agent capable of reacting with one or more of the ester groups of the cellulose acetate to form hydroxyl groups on the intermediate cellulosic ester.
  • Suitable de-esterifying agents include low molecular weight alcohols, such as methanol, ethanol, isopropyl alcohol, pentanol, R-OH, wherein R is Ci to C20 alkyl group, and mixtures thereof. Water and a mixture of water and methanol may also be used as the de-esterifying agent. Typically, most of these sulfate esters are cleaved during the controlled partial hydrolysis used to reduce the amount of acetyl substitution.
  • the reduced degree of substitution may range from 0.05 to 3, e.g., from 0.05 to 2.8, from 1.0 to 2.8, from 2.0 to 2.8, from 2.2 to 2.8, from 2.2 to 2.6, from 2.4 to 2.6, from 2.4 to 2.8, from 2.2 to 2.8, from 2.0 to 2.8.
  • the cellulose esters described herein may be prepared as a solution and used as a 3-D printing composition for producing a solid 3-D product from dope extrusion.
  • the cellulose esters described herein may be prepared as a blend with a plasticizer and used as a 3-D printing composition for producing a solid 3-D product from melt extrusion.
  • Viscosity of a cellulose ester solution is affected by molecular weight of the cellulose, degree of substitution, and concentration. Viscosity can also be adjusted by including one or more plasticizers.
  • the 3-D printing composition comprises at least one cellulose ester and a solvent and/or a plasticizer.
  • the 3-D printing composition comprises at least one cellulose ester, a solvent, and optionally a plasticizer.
  • the compositions for 3-D printing comprise one or more cellulose esters and a plasticizer, but do not comprise a solvent. Any 3-D printing composition described herein may further comprise a processing aid.
  • Any 3-D printing composition described herein may further comprise one or more additives including, but not limited to, a pigment, a dye, an adhesive, a biocide, an antifungal, an antimicrobial, an antistatic agent, a flame retardant, a degradation agent, a conductivity modifying agent, a stabilizing agent, or any combination thereof.
  • additives including, but not limited to, a pigment, a dye, an adhesive, a biocide, an antifungal, an antimicrobial, an antistatic agent, a flame retardant, a degradation agent, a conductivity modifying agent, a stabilizing agent, or any combination thereof.
  • the 3-D printing composition comprises from 10 to 50 wt.% cellulose ester, based on the total weight of the composition, e.g., from 10 to 35 wt.%, from 10 to 25 wt.%, from 10 to 20 wt%, from 20 to 50 wt. %, from 25 to 50 wt. %, from 35 to 50 wt. %, or from 40 to 50 wt.%.
  • the 3-D printing composition may comprise any organic cellulose ester including, but not limited to, cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate-propionate, cellulose acetate-butyrate, cellulose propionate-butyrate, cellulose acetate acylate.
  • the cellulose ester has a degree of substitution from 0.05 to 3 acetyl groups per glucose unit, e.g., from 0.05 to 2.8, from 1.0 to 2.8, from 2.0 to 2.8, from 2.2 to 2.8, from 2.2 to 2.6, from 2.4 to 2.6, from 2.4 to 2.8, from 2.2 to 2.8, from 2.0 to 2.8.
  • the 3-D printing composition may include a combination or mixture of cellulose esters.
  • the 3-D printing composition comprises cellulose acetate or comprises a blend of cellulose acetate and another cellulose ester.
  • the cellulose acetate has a degree of substitution from 0.05 to 3 acetyl groups per glucose unit, e.g., from 0.05 to 2.8, from 1.0 to 2.8, from 2.0 to 2.8, from 2.2 to 2.8, from 2.2 to 2.6, from 2.4 to 2.6, from 2.4 to 2.8, from 2.2 to 2.8, from 2.0 to 2.8.
  • the 3-D printing composition is free of cellulose acetate.
  • the number average molecular weight of the cellulose acetate may range from 15,000 to 100,000, (e.g., from 15,000 to 75,000; from 15,000 to 50,000; from 25,000 to 100,000; from 25,000 to 75,000; from 25,000 to 50,000; from 50,000 to 100,000; from 50,000 to 75,000). All molecular weights recited herein, unless otherwise specified, are number average molecular weights. The molecular weight may be selected based on desired hardness of the final 3-D printed product. Although greater molecular weight leads to greater hardness, greater molecular weight also increases viscosity.
  • the cellulose acetate may be provided in powder or flake form.
  • blends of different molecular weight cellulose acetate flake or powder may be used.
  • cellulose acetate having greater molecular weight has greater hardness but also greater viscosity that may make extruding the composition more difficult.
  • a high molecular weight cellulose acetate e.g., a cellulose acetate having a molecular weight above 75,000
  • a low molecular weight cellulose acetate e.g., a cellulose acetate having a molecular weight below 30,000.
  • the ratio of high molecular weight cellulose acetate to low molecular weight cellulose acetate may vary but may generally range from 1 to 50; e.g., from 1 to 10.
  • the 3-D printing composition may include a combination or mixture of two or more cellulose esters. In some embodiments, the 3-D printing composition may include a combination or mixture of one or more cellulose esters and another polymer. Such combinations or blends of multiple cellulose esters or of one or more cellulose esters and other polymer may improve processing or may improve properties of the 3-D printed object. For example, blending cellulose acetate and polycaprolactone can improve processing. As another example, blending cellulose acetate and poly(2-ethyl oxazoline) can improve properties of a 3-D printed object, such as but not limited to anti-fog.
  • the solvent may be present in an amount of from 50 to 90 wt.% based on the total weight of the composition, e.g., from 65 to 90 wt.%, from 75 to 90 wt.%, from 80 to 90 wt.%, from 50 to 80 wt. %, from 50-75 wt. %, from 50 to 65 wt. %, or from 50 to 60 wt.%.
  • the solvent may be water or may be an organic solvent generally known to one skilled in the art, including but not limited to aliphatic and aromatic solvents such as alcohols, ketones, esters, acetates, glycol ethers, and the like and may be a mixture of solvents, including a mixture of water and an organic solvent.
  • organic solvent generally known to one skilled in the art, including but not limited to aliphatic and aromatic solvents such as alcohols, ketones, esters, acetates, glycol ethers, and the like and may be a mixture of solvents, including a mixture of water and an organic solvent.
  • Useful organic solvents include, but are not limited to acetone, methylethyl ketone, methylene chloride, dioxane, dimethyl formamide, dimethyl succinate, dimethyl adipate, dimethyl glutarate, methanol, ethanol, glacial acetic acid, glycol ether ester, dimethyl carbonate, cyclohexanone, ethyl acetate, butyl acetate, and mixtures thereof.
  • the 3-D printing composition comprises a solvent
  • preferred solvents, or combinations thereof may vary depending on the specific cellulose ester, the degree of substitution, and the presence (or absence) and identity of any plasticizer.
  • the solvent should dissolve the cellulose ester and provide a solution that is flowable enough for extrusion but that is viscous enough for the extruded filament to hold a desired shape until solidified.
  • a solvent or combination of solvents may be selected to minimize undesirable skin formation that can occur on the surface of the extruded 3-D structure during solvent evaporation.
  • the boiling point of the solvent or the mixture of solvents is less than 200° C, e.g. less than 150° C or less than 100° C.
  • more than one solvent e.g., a solvent and one or more co-solvents
  • the solvents are all organic solvents.
  • the solvent includes water and one or more organic solvents.
  • the solvents may be selected so that each solvent has a different boiling point. This combination of solvents selected based on boiling point may be referred to as a layered solvent system.
  • the boiling point of the second solvent may be at least 5°C greater than the boiling point of the first solvent, e.g., at least lO°C, or at least l5°C.
  • the boiling point of the third solvent may then be at least 5°C greater than the boiling point of the second solvent, e.g., at least lO°C, or at least l5°C. This trend may continue for as many solvents as are included. For example, acetone has a boiling point of 56°C, ethyl acetate has a boiling point of 77. l°C, isopropanol has a boiling point of 82.6°C, and n-butyl acetate has a boiling point of l26°C. Generally, the first solvent is present in the greatest amount and is the most compatible with cellulose ester.
  • the advantage of such a layered solvent system is that the first solvent, such as acetone, evaporates more quickly while the less compatible but higher boiling point solvents remain for a longer duration, leading to improved clarity in the 3-D product.
  • controlled evaporation can improve fusion or isolation between extruded layers in the 3-D printed article.
  • a solvent that evaporates more slowly may function as a pseudo-plasticizer to improve appearance of the 3-D printed article by allowing a softer material between extruded layers. The solvent could eventually evaporate leaving a stable matrix or remain to leave a flexible 3-D printed article.
  • the first solvent may be present in an amount from 50 to 99 wt.% based on total weight of the solvent mixture, e.g., from 65 to 95 wt.% or from 75 to 90 wt.%; the second solvent may be present from 1 to 50 wt.% based on total weight of the solvent mixture, e.g., from 5 to 35 wt.% or from 10 to 25 wt.%. If present, additional solvents may be present from 0.1 to 10 wt.% based on total weight of the solvent mixture, e.g., from 0.5 to 7 wt.% or from 1 to 5 wt.%. In other aspects, so long as the total amount of solvents is from 50 to 90 wt.% based on total weight of the 3-D printing composition, the ratio of first solvent to second solvent and so on may vary.
  • the plasticizer may be present from 0.01 to 20 wt.%, based on the total weight of the composition, e.g., from 0.01 to 15 wt.%, from 0.05 to 10 wt.%, from 0.1 to 5 wt.%, from 1.0 to 10 wt. %, from 5-20 wt. %, from 5 to 15 wt. %, or from 5 to 20 wt.%.
  • the amount of plasticizer may be chosen to: (i) facilitate extrusion and solidification of the cellulose ester (e.g., enough plasticizer to allow extrusion and, if a solvent is present in the composition, to prevent film formation during the subsequent solvent evaporation) and (ii) maintain desirable mechanical properties of the cellulose acetate (e.g., not enough plasticizer to significantly reduce the tensile strength of a final composition).
  • Various plasticizers may be used to reduce the glass transition temperature of the cellulose ester.
  • the plasticizer may be one generally known to one of skill in the art, such as those described in U.S. Pub. No. 2015/0351311.
  • Manufacturers may choose the type and amount of plasticizer (e.g., the ratio of plasticizer to cellulose acetate) based on a number of factors including the specific cellulose ester or esters, the degree of substitution of the cellulose ester(s), the presence and identity of any solvent or solvents, compatibility with other components of a final composition, or desired properties of the 3-D product.
  • plasticizer e.g., the ratio of plasticizer to cellulose acetate
  • plasticizers are known for plasticizing cellulose esters
  • the intended end use of the 3-D product may narrow the scope of useful plasticizers.
  • some types of plasticizers may be selected because they are biodegradable, allowing for the 3-D product produced from the plasticized cellulose ester to be eco-friendly.
  • a food grade plasticizer may be preferred for certain intended end uses.
  • the term "food grade” refers to a material that has been approved for contacting (directly or indirectly) food, which may be classified as based on the material's conformity to the requirements of the United States Pharmacopeia (“USP-grade”), the National Formulary (“NF- grade”), and/or the Food Chemicals Codex (“FCC-grade”) as of April 30, 2017.
  • Food grade plasticizers include triacetin, diacetin, tripropionin, trimethyl citrate, triethyl citrate, tributyl citrate, eugenol, cinnamyl alcohol, alkyl lactones (e.g., g-valerolactone), methoxy hydroxy acetophenone
  • Useful plasticizers for the 3-D printing compositions described herein include, but are not limited to triaryl and alkyl aryl phosphates, including triphenyl phosphate, resorcinol bis(diphenyl phosphate), and o-phenyl phenyl-(bis) phenyl phosphate; alkyl phosphates, including triethyl phosphate and alkylene bis(phosphate)s; chloroalkyl phosphates, including tris- chloroisopropyl phosphate; triethyl citrate; dimethoxy-ethyl phthalate; dimethyl phthalate;
  • diethyl phthalate diethyl phthalate; methyl phthalyl ethyl glycolate; l,4-butanediol diacetate; diacetin;
  • the plasticizer is triacetin. In further embodiments, the plasticizer does not contain a phthalate (is“phthalate-free”).
  • the 3-D printing composition optionally comprises a processing aid.
  • the processing aid may be present in an amount from 0.05 to 10 wt.% based on the total weight of the 3-D printing composition, e.g., from 0.1 to 5 wt.% , or from 0.5 to 2.5 wt.%.
  • the processing aid may be selected from the group consisting of titanium dioxide, aluminum oxide, zirconium oxide, silicon dioxide, calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate and mixtures thereof.
  • the processing aid is silica.
  • the average particle size of the processing aid may vary.
  • the processing aid may have an average particle size from 0.01 to 50 pm, e.g., from 0.02 microns to 40 microns, from, from 0.05 microns to 30 microns.
  • the particle size may be determined, for example, by sieve analysis.
  • the 3-D printing composition optionally comprises an additive selected from a pigment, dye, biocide, antifungal, antimicrobial, antistatic agent, flame retardant, degradation agent, conductivity modifying agent, stabilizing agent, or any combination thereof.
  • any additive may be present in an amount from 0.01 to 10 wt.% based on the total weight of the 3-D printing composition, e.g., from 0.01 to 5 wt.% , or from 0.5 to 2.5 wt.%.
  • pigment refers to compounds and/or particles that impart color and are incorporated throughout the 3-D printing composition and the 3-D product.
  • Suitable pigments for use in conjunction with the present invention may include, but are not limited to, titanium dioxide, silicon dioxide, tartrazine, El 02, phthalocyanine blue, phthalocyanine green, quinacridones, perylene tetracarboxylic acid di-imides, dioxazines, perinones disazo pigments, anthraquinone pigments, carbon black, metal powders, iron oxide, ultramarine, calcium carbonate, kaolin clay, aluminum hydroxide, barium sulfate, zinc oxide, aluminum oxide, or any combination thereof.
  • a pigment may be present in an amount from 0.01 to 10 wt.% based on the total weight of the 3-D printing composition, e.g., from 0.1 to 5 wt.% , or from 0.5 to 2.5 wt.%.
  • dye refers to compounds and/or particles that impart color and are a surface treatment of the 3-D product.
  • Suitable dyes may include, but are not limited to, CARTASOL® dyes (cationic dyes, available from Clariant Services) in liquid and/or granular form (e.g., CARTASOL® Brilliant Yellow K-6G liquid, CARTASOL® Yellow K-4GL liquid, CARTASOL® Yellow K-GL liquid, CARTASOL® Orange K-3GL liquid, CARTASOL® Scarlet K-2GL liquid, CARTASOL® Red K-3BN liquid, CARTASOL® Blue K-5R liquid, CARTASOL® Blue K-RL liquid, CARTASOL® Turquoise K-RL liquid/granules,
  • CARTASOL® dyes cationic dyes, available from Clariant Services
  • a dye may be present in an amount from 0.01 to 10 wt.% based on the total weight of the 3-D printing composition, e.g., from 0.1 to 5 wt.% , or from 0.5 to 2.5 wt.%.
  • Suitable antimicrobials for use in conjunction with the present invention may include, but are not limited to, anti-microbial metal ions, chlorhexidine, chlorhexidine salt, triclosan, polymoxin, tetracycline, amino glycoside (e.g., gentamicin), rifampicin, bacitracin,
  • erythromycin erythromycin, neomycin, chloramphenicol, miconazole, quinolone, penicillin, nonoxynol 9, fusidic acid, cephalosporin, mupirocin, metronidazolea secropin, protegrin, bacteriolcin, defensin, nitrofurazone, mafenide, acyclovir, vanocmycin, clindamycin, lincomycin,
  • PHMB polyhexamethylene biguanide
  • PHMB derivatives e.g., biodegradable biguanides like polyethylene hexani ethylene biguanide (PEHMB)
  • chlorhexidine gluconate chlorohexidine hydrochloride
  • EDTA ethylenediaminetetraacetic acid
  • EDTA derivatives e.g., disodium EDTA or tetrasodium EDTA
  • An antimicrobial may be present in an amount from 0.01 to 10 wt.% based on the total weight of the 3-D printing composition, e.g., from 0.1 to 5 wt.% , or from 0.5 to 2.5 wt.%.
  • Suitable antistatic agents for use in conjunction with the present invention may comprise any suitable anionic, cationic, amphoteric or nonionic antistatic agent.
  • Anionic antistatic agents may generally include, but are not limited to, alkali sulfates, alkali phosphates, phosphate esters of alcohols, phosphate esters of ethoxylated alcohols, or any combination thereof. Examples may include, but are not limited to, alkali neutralized phosphate ester (e.g., TRYFAC.RTM. 5559 or TRYFRAC.RTM. 5576, available from Henkel Corporation, Mauldin, S.C.).
  • Cationic antistatic agents may generally include, but are not limited to, quaternary ammonium salts and imidazolines which possess a positive charge.
  • nonionics include the poly(oxyalkylene) derivatives, e.g., ethoxylated fatty acids like EMEREST.RTM. 2650 (an ethoxylated fatty acid, available from Henkel Corporation, Mauldin, S.C.), ethoxylated fatty alcohols like TRYCOL.RTM. 5964 (an ethoxylated lauryl alcohol, available from Henkel Corporation, Mauldin, S.C.), ethoxylated fatty amines like TRYMEEN.RTM.
  • An antistatic agent may be present in an amount from 0.01 to 10 wt.% based on the total weight of the 3-D printing composition, e.g., from 0.1 to 5 wt.% , or from 0.5 to 2.5 wt.%.
  • one component of the composition for use in 3-D printing can serve more than one purpose.
  • some phosphate plasticizers also provide flame retardant properties.
  • triaryl and alkyl aryl phosphate plasticizers generally provide flame retardant properties.
  • Some examples of flame-retardant plasticizers include triphenyl phosphate and resorcinol bis(diphenyl phosphate).
  • Some alkyl phosphates and chloroalkyl phosphates also provide flame retardant properties. Examples include triethyl phosphate, alkylene bis(phosphate)s and tris-chloroisopropyl phosphate.
  • the 3-D printing compositions described herein can be formed by mechanically mixing a cellulose ester with a solvent or a plasticizer to form a viscous solution.
  • the 3-D printing composition can be formed by mechanically mixing a cellulose ester, a solvent, and a plasticizer and/or other additives to form a viscous solution.
  • the 3-D printing composition can be formed by mechanically mixing a cellulose ester, a plasticizer, and optionally other additives without a solvent to form a viscous solution.
  • the 3-D printing composition is formed without including a solvent.
  • Cellulose esters, solvents, plasticizers, and other additives useful in the 3-D printing compositions include any described previously herein.
  • the cellulose ester is cellulose acetate and the solvent is acetone.
  • the cellulose ester is cellulose acetate
  • the solvent is acetone
  • the plasticizer is triacetin.
  • the cellulose acetate may be present from 10 to 50 wt. % based on the total weight of the 3-D printing composition, and the triacetin may be present from 0.01 to 20 wt. % based on the total weight of the 3-D printing composition.
  • the cellulose acetate may be added in flake or powder form.
  • a method of producing a 3-D product includes introducing a 3-D printing composition as described herein into a 3-D printing device, extruding the composition in a plurality of layers to produce a 3-D structure; and if a solvent is present evaporating the solvent to produce a 3-D product.
  • the 3-D printing composition is extruded through one or more nozzles as a filament that is deposited onto a build plate in a plurality of layers in a
  • the 3-D product is subjected to a post-production treatment.
  • the 3-D printing composition includes a solvent
  • a dope refers to a polymer solution and/or suspension from which filaments are produced.
  • a dope may comprise one or more polymers and one or more solvents.
  • a dope may comprise one or more polymers, one or more solvents, one or more plasticizers, and optionally other components as further detailed herein. Polymers, solvents, plasticizers, and other components useful in the present invention have been described herein. The polymer, solvent, and other components of the dope may be present in the dope at any concentration described herein for 3-D printing compositions.
  • the 3-D printing composition includes a plasticizer but no solvent, it is also referred to herein as a“polymer melt.”
  • a polymer melt refers to a 3-D printing composition that can be melt extruded to produce filaments, whether melted prior to or during the extrusion process, and whether melted or in solid (pre-melt-extruded form).
  • a polymer melt comprises one or more polymers and one or more plasticizers.
  • a polymer melt comprises one or more polymers, one or more plasticizers, and optionally other components as further detailed herein. Polymers, plasticizers, and other components useful in the present invention have been described herein. The polymer, plasticizer, and other components of the polymer melt may be present in the polymer melt at any concentration described herein for 3-D printing compositions.
  • the 3-D printing device comprises a reservoir for receiving a dope or a polymer melt composition (whether solid or melted) and at least one nozzle in fluid communication with the reservoir.
  • the 3-D printing device may further comprise a pump, screw extruder, or other conveying element for forcing the dope or polymer melt through the nozzle.
  • Optional other elements may include, but are not limited to, filtration elements, heating elements, heat exchangers (e.g., hot water, steam pipes), mixers, or any combination thereof.
  • the dope or polymer melt may be heated to a temperature from 40° C to 200° C, e.g. 40° C to 150° C, 40° C to 100° C, 60° C to 200 ° C, 60° C to 150° C, or 60° C to 100° C.
  • the 3-D printing device may include one nozzle or may include a plurality of nozzles. Each nozzle in the 3-D printing device may have a size of 0.04 mm to about 1 mm, e.g. 0.06 mm to 1 mm, 0.1 mm to 1 mm, 0.5 mm to 1 mm, 0.04 mm to 0.5 mm, 0.04 mm to 0.1 mm.
  • a filament As a filament is extruded it is deposited in a plurality of layers that combine to form a 3-D structure.
  • the method comprises a plurality of alternating extruding and evaporating steps.
  • the solvent evaporates and the filament dries to a solid.
  • a first layer may be completely dry before a second layer is deposited on the first layer.
  • the solvent in the second layer may dissolve a portion of the first layer and the first and second layers adhere when the solvent dries.
  • first layer may comprise some solvent when the second layer is deposited on the first layer.
  • the solvent evaporates after extrusion without any additional heating.
  • heat can be applied to facilitate solvent evaporation.
  • removing a solvent from filaments, or from a 3-D structure, of the present invention may involve heating the filaments, or the 3-D structure, to a temperature at or above about the evaporation temperature of the solvent to assist in removal of the solvent. Heating may be in the form of direct heat, indirect heat, or any combination thereof. Further, heating may involve heaters, heated enclosures (e.g., cabinets or tunnels), heated surfaces (e.g., hot shoes), microwaves, irradiation sources that cause additives in the filaments (e.g., nanoparticles) to produce heat, or any combination thereof.
  • heated enclosures e.g., cabinets or tunnels
  • heated surfaces e.g., hot shoes
  • microwaves irradiation sources that cause additives in the filaments (e.g., nanoparticles) to produce heat, or any combination thereof.
  • evaporating the solvent from filaments, or from a 3-D structure is accomplished at ambient temperature, i.e., without additional heating.
  • Ambient temperature may be from 65° C to 85° C, e.g. from 70° C to 80° C.
  • producing a 3-D product of the present invention may involve a post-production treatment, for example, a chemical treatment, thermal treatment, or polishing.
  • the 3-D product may be treated to achieve a certain surface functionality on the product.
  • the 3-D product of the present invention may comprise a surface
  • biodegradability sites e.g., defect sites to increase surface area to enhance biodegradability
  • chemical handles e.g., carboxylic acid groups for subsequent functionalization
  • active particle binding sites e.g., sulfide sites binding gold particles or chelating groups for binding iron oxide particles
  • sulfur moieties or any combination thereof
  • Some embodiments may involve dipping, spraying, ionizing, functionalizing, acidizing, hydrolyzing, exposing to a plasma, exposing to an ionized gas, or any combination thereof to achieve surface functionalities.
  • chemically treating the 3-D product may comprise exposing the 3-D product to an acid (e.g., sulfuric acid, nitric acid, acetic acid, hydrofluoric acid, hydrochloric acid, and the like), a base (e.g., sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium tartrate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium bicarbonate, sodium sulfate, sodium bicarbonate, sodium sulfate, sodium bicarbonate, sodium sulfate, sodium bicarbonate, sodium sulfate, sodium bicarbonate, sodium sulfate, sodium s
  • a metal hydroxide such as but not limited to sodium or potassium hydroxide
  • a reducing agent e.g., LiAlH 4 , NaBH 4 , Th/Pt, and the like
  • a Grignard reagent e.g., CTbMgBr, and the like
  • a trans-esterification reagent e.g., R— NH 3 , such as CH3NH3
  • acylation amination, etherfi cation, saponification, or a combination thereof.
  • Chemically treating the 3-D product may comprise exposing at least a portion of the 3-D product to a metal hydroxide, for example sodium or potassium hydroxide.
  • a metal hydroxide for example sodium or potassium hydroxide.
  • thermally treating the 3-D printed product comprises heating the 3-D printed product, but the 3-D printed product should not be heated to or above the Tg of the polymer composition of the 3-D product.
  • the 3-D printed product is heated at or below the heat deflection temperature of the polymer composition of the 3-D product.
  • polishing the 3-D product comprises any known method of polishing an object. For example, polishing may include buffing using a rotary polisher.
  • Products that can be made by the methods described herein are not particularly limited and can include, but are not limited to, any 3-D article, such as a device, structure, prototype, or any product typically formed from cellulose acetate.
  • methods described herein can be used to make tools, toys, household products, personal hygiene products, and filtration devices.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)

Abstract

L'invention concerne une composition et des procédés d'impression 3D utilisant des esters de cellulose. Les compositions sont des compositions d'impression 3D comprenant au moins un ester de cellulose, par exemple, un acétate de cellulose, un solvant et/ou un plastifiant, et éventuellement d'autres additifs. Les procédés comprennent l'introduction des compositions 3D dans un dispositif d'impression 3D, l'extrusion de la composition dans une pluralité de couches pour produire une structure 3D, et si un solvant est présent, l'évaporation du solvant pour produire un produit 3D.
PCT/US2019/012805 2018-01-09 2019-01-09 Compositions et procédés d'impression 3d utilisant un ester de cellulose WO2019139927A1 (fr)

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