Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
• • C—CHEMISTRY; METALLURGY
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  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/08—Homopolymers or copolymers of acrylic acid esters
• • 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
  • B29C64/30—Auxiliary operations or equipment
  • B29C64/307—Handling of material to be used in additive manufacturing
  • B29C64/321—Feeding
• • 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
  • B33Y70/10—Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/08—Cellulose derivatives
  • C08L1/10—Esters of organic acids, i.e. acylates
  • C08L1/12—Cellulose acetate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
  • C08L33/12—Homopolymers or copolymers of methyl methacrylate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
• • 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
  • 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
  • B29C64/30—Auxiliary operations or equipment
  • B29C64/307—Handling of material to be used in additive manufacturing
  • B29C64/314—Preparation
• • 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
  • B29K2033/00—Use of polymers of unsaturated acids or derivatives thereof as moulding material
  • B29K2033/04—Polymers of esters
  • B29K2033/08—Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
• • 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
  • 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
  • B33Y80/00—Products made by additive manufacturing
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/24—Acids; Salts thereof
  • C08K3/26—Carbonates; Bicarbonates
  • C08K2003/265—Calcium, strontium or barium carbonate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/30—Sulfur-, selenium- or tellurium-containing compounds
  • C08K2003/3045—Sulfates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
  • C08K3/041—Carbon nanotubes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
  • C08K3/042—Graphene or derivatives, e.g. graphene oxides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
  • C08K3/346—Clay
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
  • C08K3/36—Silica
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/40—Glass
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
  • C08K7/04—Fibres or whiskers inorganic
  • C08K7/06—Elements
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
  • C08K7/04—Fibres or whiskers inorganic
  • C08K7/14—Glass
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2207/00—Properties characterising the ingredient of the composition
  • C08L2207/53—Core-shell polymer

Definitions

• the invention relates to an acrylic alloy composition that can be 3-D printed by a material extrusion additive manufacturing process, to an acrylic filament that has a very uniform diameter useful in the extrusion additive manufacturing process, to acrylic articles made from the acrylic alloy composition by a material extrusion additive process, and to a material extrusion additive manufacturing process for producing the acrylic articles.
• the acrylic alloy composition is an alloy of an acrylic polymer, and a low melt viscosity polymer, such as polylactic acid.
• the alloy may optionally be impact modified, preferably with hard core core- shell impact modifiers.
• Polylactic acid is widely used for desktop home printers as it prints well, and has very low warpage. Unfortunately it has a low use temperature, poor chemical stability and is yellowish when not colored with dyes or pigments. ABS is a more stable commonly used "engineering" thermoplastic for 3-D printing, and has a higher use temperature - but has a high warpage level, is not transparent, and has a printed elongation at break of less than 6%.
• Acrylic polymers are well known for their clarity, sparkling color, surface gloss, depth of image, and weather resistance. They have similar use temperatures to ABS. Unfortunately, the brittleness associated with acrylic polymers makes them impractical for making filaments for use in extrusion additive 3-D printing.
• an alloy of a polymethyl methacrylate -based polymer with a low viscosity polymer such as polylactic acid (PLA), and optionally having impact modifiers provides an acrylic filament that has the flexibility and flow properties to be printed, while retaining the transparency and strength of PMMA.
• PMMA polylactic acid
• composition exhibits a very low variance in diameter when extruded as a filament, and the resulting filament is capable of being coiled.
• the composition of the invention can be easily printed without the need for adhesives or a heated chamber.
• the invention relates to an acrylic alloy composition that is useful in a material extrusion additive manufacturing process.
• the acrylic alloy composition comprises:
• A. a polymer matrix blend comprising:
• one or more acrylic polymers having a weight average molecular weight of from 50,000 to 300,000, and preferably from 75,000 to 150,000 g/mol, and having less than 5% above 500,000 g/mol,
• Pa-sec preferably less than 10,000, more preferably from 50 to 1,000 Pa-sec at a temperature of 230°C, and a viscosity of 20 to 2,000 Pa-s at a shear rate of 100 sec "1 at a temperature of 230°C, as measured by a rotational viscometer according to ASTM C965.
• the composition can contain additives, including additives that provide visual special effects.
• the invention also relates to filaments for a material extrusion additive manufacturing process having a very uniform diameter when made by conventional filament extrusion equipment, in which the diameter of the filament varies by less than 5% over a 10 foot section.
• the invention further relates to a material additive extrusion process using the acrylic alloy composition, and acrylic articles formed by the process.
• Figure 1 depicts the shear related viscosity of Samples 1 and 3.
• the invention relates to an acrylic composition that can be formed by a material extrusion additive manufacturing process (also referred to in this application as 3D printing), to an acrylic filament useful in the process having a very uniform diameter, to acrylic articles made from the alloy composition of the invention, and to a process for producing the acrylic extrusion additive articles.
• a material extrusion additive manufacturing process also referred to in this application as 3D printing
• percent shall mean weight percent.
• Molecular weight is a weight average molecular weight as measured by GPC. In cases where the polymer contains some cross-linking, and GPC cannot be applied due to an insoluble polymer fraction, soluble fraction / gel fraction or soluble faction molecular weight after extraction from gel is used.
• Copolymer is used to mean a polymer having two or more different monomer units.
• Polymer is used to mean both homopolymer and copolymers. Polymers may be straight chain, branched, star, comb, block, or any other structure. The polymers may be homogeneous, heterogeneous, and may have a gradient distribution of co-monomer units.
• Low shear viscosity is a measure of the melt viscosity (ASTM D3835- 0) at a relatively low shear rate. This relates to the viscosity of the melt following printing. For purposes of this invention, the low shear rate at which viscosity is measured is at 1 sec "1 . The actual shear rate of the polymer alloy following printing is essentially zero.
• High shear viscosity as used herein is a measure of the melt viscosity at a relatively high shear rate. This relates to the viscosity of the melt as it moves through the nozzle on a 3-D printer.
• the high shear rate viscosity is measured herein as the melt viscosity at a shear of 100 sec "1 .
• the viscosity of the melt under high shear is generally lower than the viscosity of the polymer melt under low shear, due to shear thinning.
• the acrylic alloy of the invention contains at least one acrylic polymer, at least one low melt viscosity polymer that is miscible, semi-miscible or compatible with the acrylic polymer, and optionally impact modifier.
• the acrylic alloy may further contain other additives.
• Alkyl methacrylate monomer is preferably methyl methacrylate, which may make up from 50 to 100 percent of the monomer mixture. 0 to 50 percent of other acrylate and methacrylate monomers or other ethylenically unsaturated monomers, included but not limited to, styrene, alpha methyl styrene, acrylonitrile, and crosslinkers at low levels may also be present in the monomer mixture.
• methacrylate and acrylate monomers useful in the monomer mixture include, but are not limited to, methyl acrylate, ethyl acrylate and ethyl methacrylate, butyl acrylate and butyl methacrylate, iso-octyl methacrylate and acrylate, lauryl acrylate and lauryl methacrylate, stearyl acrylate and stearyl methacrylate, isobornyl acrylate and methacrylate, methoxy ethyl acrylate and methacrylate, 2-ethoxy ethyl acrylate and methacrylate,
• Alkyl (meth) acrylic acids such as methacrylic acid and acrylic acid can be useful for the monomer mixture.
• the acrylic polymer is a copolymer having 70 - 99.5 weight percent of methyl methacrylate units and from 0.5 to 30 weight percent of one or more C 1-8 straight or branched alkyl acrylate units.
• the acrylic polymer has a weight average molecular weight of from 50,000 g/mol to 300,000 g/mol, and preferably from 75,000 g/mol to 150,000 g/mol. It has been found that the use of acrylics having a lower weight average molecular weight in the range, provides an increase in the density of material extrusion additive printed articles, increases the transparency and reduces warpage.
• the acrylic polymer contains little or no very high molecular weight fraction polymer, with less than 5 weight percent of the acrylic polymer, and preferably less than 2 weight percent of the acrylic polymer having a molecular weight of greater than 500,000 g/mol.
• the acrylic polymer comprises a blend of two or more of the polymers described in the above two embodiments.
• the acrylic polymer can be formed by any known means, including but not limited to bulk polymerization, emulsion polymerization, solution polymerization and suspension polymerization.
• the low melt viscosity polymer in the acrylic alloy composition must be compatible, semi-miscible, or miscible with the acrylic polymer.
• the low melt viscosity polymer and acrylic polymer should be capable of being blended in a ratio such that a single intimate mixture is generated without separation into distinct bulk phases.
• low melt viscosity polymer means polymers having a melt flow rate of greater than 10 g/10 minutes, and preferably greater than 25g/10 minutes as measured by ASTM D1238 at 230°C/10.4kg of force.
• the low melt viscosity polymer is a low molecular weight acrylic polymer or copolymer, meeting the high melt flow rate criteria.
• the low molecular weight acrylic polymer has a weight average molecular weight of less than 70,000, preferably less than 50,000, more preferably less than 45,000, and even less than 30,000 g/mol.
• Acrylic copolymers are preferred, and copolymers with a Tg of less than 100°C, and less than 90°C are preferred from increased flexibility.
• the low melt viscosity polymer of the invention is a polymer other than an acrylic polymers.
• the non-acrylic low melt viscosity polymer of this invention includes, but is not limited to, polyesters, cellulosic esters, polyethylene oxide, polypropylene glycol, polyethylene glycol, polypropylene glycol, styrene-acrylonitrile copolymers, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate copolymers, polyvinylidene fluoride and its copolymers, olefin- acrylate copolymers, olefin-acrylate-maleic anhydride copolymers, and maleic anhydride- styrene- vinyl acetate copolymers, and mixtures thereof.
• Useful polyesters include, but are not limited to: poly(butylene terephthalate), poly(ethylene terephthalate), polyethylene terephthalate glycol, polylactic acid.
• a preferred polyester is polylactic acid.
• Useful cellulosic esters include, but are not limited to: cellulose acetate, cellulose triacetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate phthalate.
• the low melt viscosity polymer has a weight average molecular weight higher than the entanglement molecular weight of that polymer, as measured by gel permeation chromatography.
• the low melt viscosity polymer of the invention makes up from 5 to 60 weight percent of the total alloy composition, preferably from 9 to 40 weight percent.
• the acrylic alloy of the invention can contain no impact modifier, in a preferred embodiment the acrylic alloy includes one or more types of impact modifiers.
• the acrylic composition contains impact modifiers at a level of from 5 to 60 weight percent, preferably 9 to 40 weight percent, and more preferably from 20 to 45 weight percent, based on the overall alloy composition.
• the impact modifiers can be any impact modifier that is compatible, miscible, or semi-miscible with the acrylic alloy composition, as known in the art.
• Useful impact modifiers include, but are not limited to linear block copolymers and both soft- core and hard-core core-shell impact modifiers.
• the impact modifiers have acrylic blocks, or acrylic shells.
• the impact modifier provides elongation, flexibility, and toughness.
• the impact modifier of the invention is a multi-stage, sequentially-produced polymer having a core/shell particle structure of at least three layers made of a hard core layer, one or more intermediate elastomeric layers, and a hard shell layer.
• the presence of a hard core layer provides a desirable balance of good impact strength, high modulus, and excellent UV resistance, not achieved with a core/shell modifier that possesses a soft-core layer.
• the hard core layer (Tg > 0°C, preferably Tg > 20 °C) is typically a single composition polymer, but can also include the combination of a small amount of a low Tg seed on which the hard core layer is formed.
• a small 5% rubber core seed that becomes dispersed into a hard core layer would be included in the invention as a hard core layer, as long as the combination behaves as a hard core layer.
• the hard core layer can be chosen from any thermoplastic meeting the Tg requirements.
• the hard core layer is composed primarily of methacrylate ester units, acrylate ester units, styrenic units, or a mixture thereof.
• Methacrylate esters units include, but are not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec- butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate and 2-methoxyethyl methacrylate.
• Acrylate ester units include, but are not limited to, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, cycloheyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate and 2-methoxyethyl acrylate.
• the acrylate ester units are chosen from methyl acrylate, ethyl acrylate, n-butyl acrylate, 2- ethylhexyl acrylate and octyl acrylate.
• Styrenics units include styrene, and derivatives thereof such as, but not limited to, alpha-methyl styrene, and para methyl styrene.
• the hard-core layer is all-acrylic.
• the intermediate layer or layers are elastomeric, having a Tg of less than 0°C, and preferably less than -20°C.
• Preferred elastomers include polymers and copolymers of alkyl acrylates, dienes, styrenics, and mixtures thereof.
• the soft intermediate layer is composed mainly of acrylate ester units.
• Acrylate ester units useful in forming the soft block include, but are not limited to, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, cycloheyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2- hydroxyethyl acrylate and 2-methoxyethyl acrylate.
• the acrylate ester units are chosen from methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and octyl acrylate.
• Useful dienes include, but are not limited to isoprene and butadiene.
• Useful styrenics include, but are not limited to alpha-methyl styrene, and para methyl styrene.
• the shell layer can be made of one or more shell layers, having a Tg > 0°C, more preferably Tg > 20 °C.
• the shell layer may be the same or different composition from the hard core layer.
• the multi-stage polymer is a three stage composition wherein the stages are present in ranges of 10 to 40 percent by weight, preferably 10 to 20 percent, of the first stage (a), 40 to 70 percent, preferably 50 to 60, of the second intermediate stage (b), and 10 to 50 percent, preferably 20 to 40, of the final stage (c), all percentages based on the total weight of the three- stage polymer particle.
• the core layer is a crosslinked polymethylmethacrylate - ethylacrylate copolymer
• the middle layer is a crosslinked polybutylacrylate-styrene copolymer
• the outer shell is a polymethylmethacrylate-ethylacrylate copolymer.
• the multi-stage polymer can be produced by any known technique for preparing multiple-stage, sequentially-produced polymers, for example, by emulsion polymerizing a subsequent stage mixture of monomers in the presence of a previously formed polymeric product.
• the term "sequentially emulsion polymerized” or “sequentially emulsion produced” refers to polymers which are prepared in aqueous dispersion or emulsion and in which successive monomer charges are polymerized onto or in the presence of a preformed latex prepared by the polymerization of a prior monomer charge and stage. In this type of polymerization, the succeeding stage is attached to and intimately associated with the preceding stage.
• the refractive index of the core/shell particle matches the total refractive index of the matrix made of the acrylic polymer and the low melt viscosity polymer.
• match is meant that the refractive index of the core/shell particle should be within 0.03 units of the matrix polymer blend, and preferably within 0.02 units.
• the acrylic alloy of the invention could contain reactive functional groups, either by using a functional monomer, or by a post-treatment. Once the functional polymer is processed into a useful article, it could then be reacted or cross-linked, such as by UV radiation, or e-beam, for increased integrity.
• Cross-linking is known in the art to generally increase the tensile and flexural moduli, and reduce solubility and permeability of the cross- linked material, all of which could be advantageous physical property enhancements depending on the material's final application. Additives
• the acrylic alloy may further contain other additives typically present in acrylic formulations, including but not limited to, stabilizers, plasticizers, fillers, coloring agents, pigments, antioxidants, antistatic agents, surfactants, toner, refractive index matching additives, additives with specific light diffraction or light reflection characteristics, and dispersing aids. If fillers are added, they represent 0.01 to 50 volume percent, preferably 0.01 to 40 volume percent, and most preferably from 0.05 to 25 volume percent of the total volume of the acrylic alloy composition.
• the fillers can be in the form of powders, platelets, beads and particles. Smaller materials, with low aspect ratios are preferred, to avoid possible fouling of the nozzle, though this is less important when the acrylic alloy is used with larger nozzle sizes.
• Useful fillers include, but are not limited to, carbon fiber, carbon powder, milled carbon fiber, carbon nanotubes, glass beads, glass fibers, nano-silica, Aramid fiber, polyarylether ketone fibers, BaS0 4 , talc, CaC0 4 , graphene, nano-fibers (generally having an average fiber length of from 100 to 150 nm) and hollow glass or ceramic spheres.
• the filler is added to produce special visual effects.
• Useful fillers include colorants, dyes, and inorganic particles, including fluorescent dyes, metal filings, and flakes.
• Natural-looking variegated materials that have a metallic or opalescent appearance can be made to simulate natural materials, such as granite, minerals, stone, metal ore
• the metal or pearlescent material is present in the alloy at from 0.01 to 10 weight percent, and preferably 3.5 to 6.5% weight percent, based on the weight of the alloy composition.
• the alloy composition contains pearlescent compounds and no metal compound.
• the thermoplastic composite contains pearlescent compounds and metal
• thermoplastic composite contain metal
• Metal compounds useful in the invention include, but are not limited to, metal flakes, chips and filings.
• Useful metal compounds include metals, metal-containing molecules and complexes of transition metals, or lanthanide metals, and combinations thereof. Examples include aluminum, copper, silver, gold, platinum, palladium, nickel, cobalt, tin, niobium, chromium, stainless steel, and combinations or alloys thereof, including, for example, brass and bronze.
• the metal compound may also be a metal carbide, metal oxide, metal nitride, metal sulfide, and combinations thereof.
• the metal compounds can have particle sizes averaging from 1 microns to 25 micron and preferably 2 micron to 20 micron in the largest direction.
• the metal compounds may be flat flakes, or may be particles of various shapes.
• Metal flake pigments generally have a thickness in the range of from 40 to 150 nm.
• Pearlescent compounds useful in the invention are those known in the art and include, but are not limited to, platelets of mineral mica which is muscovite or potassium aluminum hydroxide fluoride, and platelets based on titanium dioxide.
• the platelets are coated with a thin layer of metal oxide selected from the group consisting of rutile titanium dioxide, ferric oxide and tin oxide and mixtures thereof.
• the pearlescent compound platelets generally have a particle size of about 2 to about 130 microns, more preferably about 10 to about 50 microns.
• the pearlescent pigments may be colored or non-colored.
• the acrylic polymer, low melt viscosity polymer, and optional impact modifier and other additives can be blended together in any order, and by any means known in the art to form the acrylic alloy composition of the invention.
• the components can be dry-blended prior to being melted, or directly melt blended together, such as in an extruder, or intimately mixed in a suitable solvent.
• the acrylic alloy composition of the invention can be defined by its low shear and high shear viscosity.
• the acrylic alloy composition of the invention has a low shear rate viscosity as measured at 1 sec "1 of less than 100,000 Pa-s. by a rotational viscometry according to ASTM C965, and preferably of less than 10,000 Pa-s, and more preferably less than 1,000 Pa-s at a temperature of 230°C.
• the low shear viscosity is greater than 50 Pa-s, and more preferably greater than 100 Pa-s. If the low shear viscosity is less than this, it is likely not to have a sufficient melt strength for the production of filament.
• this low-shear viscosity range seems to allow the printed polymer to stay where it is placed, and yet still be fluid enough for good interlayer adhesion and fusion.
• the low and high shear viscosity ranges are for the alloy composition before the addition of additives. Some additives could push the viscosity much higher.
• the acrylic alloy composition has a high shear viscosity of from 20 to 2,000 Pa-s, preferably 25 to 1,000 Pa-s, preferably 30 Pa-s to 500 Pa-s, at the temperature of deposition and 100 sec "1 .
• the key viscosity behavior is a combination of both the viscosity of the material coming out of the nozzle, and how fluid the material stays as the thermoplastic solidifies.
• a typical nozzle temperature for use in determining the high and low shear viscosity is 230°C.
• composition of the invention include:
• a compression molded plaque formed from a clear acrylic alloy composition of the invention having a 2 mm thickness has a total white light transmittance of greater than 80%, preferably greater than 90% and most preferably greater than 92%, with a haze of less than 10%, preferably less than 4%, when measured according to ASTM D1003.
• the composition of the invention has a tensile elongation, as measured by ASTM D638 of greater than 10 percent, and preferably greater than 20 percent.
• Little or no warpage, as measured using the following warp test Various thin walls of about 1 cm in height, and from 2 cm to 20 cm in length are printed by two passes of the nozzle onto a heated glass base plate heated to the material's vicat temperature. The degree of warpage was observed qualitatively (see explanation in example 3) by viewing the printed material from the side, based on the level of detachment from the base plate. The warpage relates to the ability of a part to adhere to the base plate of a melt extrusion printer, which is necessary for successful printing.
• Yield stress The stress at yield of greater than 30 and more preferably greater than 35 MPa when measured by ASTM D638.
• Fill density articles that are extrusion additive manufactured with the acrylic alloy composition of the invention have a fill density of greater than 85 percent, preferably greater than 90 percent, and most preferably greater than 95 percent, as calculated by dividing the density of the printed part by the bulk density of the material.
• Extrusion additive manufactured articles using the acrylic alloy composition have a light transmittance of greater than 50%, preferably greater than 60%, and more preferably greater than 65% when measured on a 2.1 mm thick sample using ASTM D1003, the printed article having 10 layers and each layer having line width of 0.4 mm.
• the acrylic composition is extruded into a filament, for use in a material extrusion additive process.
• the filament can be a single strand of the acrylic composition, or can be in the form of a coextruded multi-phase filament.
• the filament has a middle layer composition of the acrylic alloy, surrounded by a sheath containing a different acrylic composition, for example containing a special effects additive, or visa versa.
• Filament formed from the acrylic composition of the invention has little shrinkage or warpage, forming a filament that is very uniform in diameter.
• the filament having the acrylic composition of the invention varies in diameter by less than +/- 5% over a ten foot length, and preferably less than 3 percent variance in diameter over ten foot of length.
• the low variance in the diameter of the filament is a key to its use in the material extrusion additive manufacturing process, as the calculations on the feed rate, and thereby the resulting density of the printed article, are based on calculations assuming a constant filament diameter.
• the acrylic alloy of the invention is used as a powder or pellets, and in a preferred embodiment is formed into a filament, generally by an extrusion process.
• the acrylic alloy composition will be 3D printed in a material extrusion (fused deposition modeling, fused filament fabrication) style 3D printer with or without filaments (any size diameter, including 1.75mm, 2.85mm or other sizes) and with any sized nozzle at any speed that can use filament, pellets, powder or other forms of the acrylic alloy composition.
• the 3-D printing of this invention is not a laser sintering process.
• the compositions could be made into filaments for such purposes. They could potentially be even sprayed-nozzled onto the surface (sprayed melted plastic) to be printed, such as by Arburg Freeformer technology.
• a general description of the printing process would involve the following steps: Feeding the acrylic alloy composition filament, pellets or powder into the 3D printer.
• the computer controls of the printer will be set to provide a set volume flow of material, and to space the printed lines at a certain spacing.
• the machine will feed the acrylic alloy composition to a heated nozzle at the set speed, the printer moving the nozzle into the proper position for depositing the set amount of acrylic alloy composition.
• the polymer has a low shear melt viscosity as described above.
• the printer would generally have a heated bed of 50 - 150 °C (preferably above 60°C).
• the 3-D printer is programmed to operate at a slight overflow of 1% to 10% overflow. This means that the volume of the acrylic alloy composition fed by the printer is higher than the calculated volume required for the 3-D article being formed.
• the overflow packs the acrylic alloy composition closer together, increasing the part density while increasing the strength, mechanical, and optical properties of the printed article.
• the overflow can be set by two different means. In the first method, the software is set to feed a higher percent of material into the nozzle than would be normally needed. In the second method, the software would be set to decrease the spacing between lines, and thus create an overlap in the lines, resulting in extra material being printed into the article.
• Process parameters of the 3-D printer can be adjusted to minimize shrinkage and warpage, and to produce 3-D printed parts having optimum strength and elongation.
• the use of selected process parameters applies to any extrusion/melt 3D printer, and preferably to filament printing.
• Sample 1 is an impact modified polymethyl methacrylate polymer blended with polylactic acid, having 35-45% impact modifier, and about 25-35% polylactic acid, and a melt flow rate at 230°C and 3.8 kg of about 3.9 g/10 min.
• Sample 2 (comparative): an impact modified polymethyl methacrylate polymer blended with polylactic acid, having 20-30% impact modifier, and about 35-40% polylactic acid, and a melt flow rate at 230°C and 3.8 kg of about 3.9 g/10 min.
• the acrylic copolymer contains a high molecular weight polymer component.
• Sample 3 is an impact modified polymethyl methacrylate polymer blended with polylactic acid, having 25 - 35% impact modifier, and about 25-35% polylactic acid, and a melt flow rate at 230°C and 3.8 kg of about 15 g/10 min.
• Sample 4 Impact modified acrylic copolymer without a high molecular weight component, having about 35-42% impact modifier, and about 10-15% of a matting agent. The viscosities of several of the samples under differing shear rates, is shown in Figure 1.
• Filaments were made using a desktop mini extruder ( ⁇ lft screw length) Filabot extruder, by inputting dried pellets and producing filament.
• the Filabot has only one adjustable setting (extruding temp), and using that and the distance of air cooling (height from extruder to collecting box) we could tune the diameter of filament to the desired filament diameter (between 2.75 - 2.9mm). Once set, the diameter of the filament extruded would be very uniform, within +0.05 mm of the mean.
• the temperatures used in the examples were between 180 and 210°C. Lower temperatures would cause the screw of the extruder to stop turning (too high torque), and higher temperature would cause the filaments to stick to each other as the cooling time/distance became insufficient. In a more robust system with more powerful torque and a cooling line the processing range could be increased.
• Example 2 Extrusion printing The filaments were dried overnight and 3D printed on an Ultimaker® 2 desktop FDM
• FFF material extrusion
• base warpage being critical in that if a part does not adhere to the base then the part cannot be printed, and it is an indication of overall warpage though that is more difficult to quantify).
• the test involved printing thin lines/walls (of 0.8mm thick, two paths of the nozzle) of various lengths of different materials on a heated glass plate (heated to the material's vicat temp) and looking to see which materials and at what lengths the parts warped / came off the plate.
• the lengths tested were from 2cm to 20cm and a height of about 1cm.
• A No warpage
• B Occasional warpage
• C Small warpage
• Example 4 Printed parts - Mechanical and Optical Properties
• Samples 1 and 3 of the invention give significant improvements in elongation (13-20% strain at break compared to 6% for ABS and PLA) while maintaining similar or improved stress at yields compared to ABS.
• An acrylic alloy composition for use in material extrusion additive manufacturing comprising:
• A. a polymer matrix blend comprising: 1) one or more acrylic polymers having a weight average molecular weight of from
• the acrylic composition of aspect 1 or 2 wherein said composition comprises two or more different acrylic polymers.
• said polymer matrix blend comprises one acrylic polymer having a weight average molecular weight of from 50,000 to 300,000 g/mol of Al), and a second acrylic polymer is the low viscosity polymer A2).
• any of aspects 1 - 6, wherein said low viscosity polymer(s) is not an acrylic polymer, and is selected from the group consisting of polyesters, cellulosic esters, polyethylene oxide, polypropylene glycol, polyethylene glycol, polypropylene glycol, styrene - acrylonitrile copolymers, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate copolymers, olefin-acrylate copolymers, olefin-acrylate-maleic anhydride copolymers, polyvinylidene fluoride and maleic anhydride- styrene- vinyl acetate copolymers.
• said polyester is selected from the group consisting of poly(butylene terephthalate), poly(ethylene terephthalate), polyethylene
• additives selected from the group consisting of fillers, carbon fiber, milled carbon fiber, carbon powder, carbon nanotubes, glass beads, glass fibers, nano-silica, clays, nanoclays, Aramid fiber, polyaryl ether ketone fibers, BaSC , talc, CaC0 3 , graphene, milled carbon fibers, nano-fibers, and hollow spheres, dyes, colorants,
• a filament for 3-D printing comprising the composition of any of aspects 1 - 15, wherein the filament varies by less than +/- 5% in diameter over ten feet of length.
• a process for forming an extrusion additive (3D) acrylic article comprising the steps of:

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• 2017
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