Impact resistant 3D printable polymer blend and articles made therefrom

Abstract

A composition useful for additive manufacturing safety devices such as helmets is comprised of a melt blend of a polycarbonate and polycaprolactone and in particular a polycarbonate that is a copolymer of polysiloxane and polycarbonate, which may also be accompanied by domains of polysiloxane dispersed within the melt blend. The composition desirably is blended by melting the polycarbonate at higher temperature and then later introducing the polycaprolactone at a lower temperature under shear such as exhibited by a twin screw extruder.

Description

IMPACT RESISTANT 3D PRINTABLE POLYMER BLEND AND ARTICLES MADE THEREFROMFIELD

[0001] The invention relates to a composition of comprised of polymer blend and method to make them for use in 3D printing to made safety devices such as a helmet.BACKGROUND

[0002] Additive manufacturing of thermoplastic polymers typically requires localized melting in layered patterns that then fuses and supports subsequent layers. Fused filament fabrication (FFF), which is also commonly called plastic jetprinting has been used to form 3d parts by using thermo plastic filaments that are drawn into a nozzle heated, melted and then extruded where the extruded filaments fuse together upon cooling (see, for example, U.S. Patent Nos. 5,121,329 and 5,503,785). Polyamides have been commonly used in FFF. However, Because of rheological properties (e.g., low melt flows) and moisture sensitivity, polyamides have generally required the use of elevated temperature stages, atmosphere controlled FFF printers or chopped fibers to realize desired articles for applications such as helmets.

[0003] Accordingly, it would be desirable to provide a polymer composition to form FFF manufactured articles for safety devices avoiding one or more of the issues in the prior art such as described above.SUMMARY

[0004] It has been discovered that a polymer blend of polycarbonate and polycaprolactone may be suitable for FFF while realizing the desired properties such as impact resistance, low moisture sensitivity and sufficient z direction adhesion. In a particular embodiment, the blend may also be comprised of a polysiloxane or a polycarbonate that is a copolymer with a polysiloxane. Other useful compounds may also be included in the composition such as a plasticizer and an impact modifier.1SUBSTITUTE SHEET (RULE 26)

[0005] A first illustration of the invention is a composition comprising a melt blend of a polycarbonate, and a polycaprolactone. Desirably, the composition is also comprised of a polysiloxane.

[0006] A second illustration of the invention is a method of forming an additive manufactured article, comprising heating and extruding a filament of the composition of the first illustration and depositing the extruded filament in multilayers by a fused filament fabrication (FFF) additive manufacturing method.

[0007] A third aspect of the invention is a method of melt blending a polycarbonate, polysiloxane and polycaprolactone comprising, heating for a total time above the polycarbonate's melt temperature, the polycarbonate, and polysiloxane for an initial time to form an initial polymer melt, adding, after the initial time, the polycaprolactone and a plasticizer at an interim time later than the initial time to form a melt blend and cooling to form a melt blended composition.

[0008] A fourth aspect of this invention a safety device comprised of a fused filament fabrication manufactured article comprising a melt blend of a polycarbonate and polycaprolactone.DETAILED DESCRIPTION

[0009] The explanations and illustrations presented herein are intended to acquaint others skilled in the art with the invention, its principles, and its practical application. The specific embodiments of the present disclosure as set forth are not intended to be exhaustive or limit the scope of the disclosure.

[0010] In an embodiment, an article or composition is comprised of a polycarbonate and polycaprolactone with typically the majority of the composition being the polycarbonate (e.g., at least 50%, 60% or 70% to about 1%, 5% or 10% by weight of the polycarbonate and polycaprolactone).

[0011] The polycarbonate may be any suitable such as those known in the art. Illustratively the polycarbonate is "Polycarbonate" as used herein means a polymer or copolymer having repeating structural carbonate units of formula (1):2SUBSTITUTE SHEET (RULE 26)(1)

[0012] wherein at least 60 percent of the total number of R1groups are aromatic, or each R1contains at least one C6-30 aromatic group. Specifically, each R1can be derived from a dihydroxy compound such as an aromatic dihydroxy compound of formula (2) or a bisphenol of formula (3), as follows:

[0013] In formula (2), each Rhis independently a halogen atom, for example bromine, a Ci-io hydrocarbyl group such as a Ci-io alkyl, a halogen-substituted Ci-io alkyl, a Ce-io aryl, or a halogen-substituted Ce-io aryl, and n is 0 to 4.

[0014] In formula (3), Raand Rbare each independently a halogen, C1-12 alkoxy, or Ci- 12 alkyl, and p and q are each independently integers of 0 to 4, such that when p or q is less than 4, the valence of each carbon of the ring is filled by hydrogen. In certain embodiments, p and q are each 0, or p and q are each 1, and Raand Rbare each a C1-33SUBSTITUTE SHEET (RULE 26)alkyl group, specifically methyl, disposed meta to the hydroxy group on each arylene group. Xais a bridging group connecting the two hydroxy-substituted aromatic groups, where the bridging group and the hydroxy substituent of each Cg arylene group are disposed ortho, meta, or para (specifically para) to each other on the Cg arylene group, for example, a single bond, —0—, — S— , — S(=0)— ,— $(=0)2— (e.g., bisphenol-S polycarbonate, polysulfone), — C(=0)— (e.g., polyketone), or a C1-18 organic group, which can be cyclic or acyclic, aromatic or non-aromatic, and can further comprise heteroatoms such as halogens, oxygen, nitrogen, sulfur, silicon, or phosphorous. For example, Xacan be a substituted or unsubstituted C3-18 cycloalkylidene; a Ci-25 alkylidene of the formula — C(RC)( Rd) — wherein Rcand Rdare each independently hydrogen, C1-12 alkyl, C1-12 cycloalkyl, C7-12 arylalkyl, C1-12 heteroalkyl, or cyclic C7-12 heteroarylalkyl; or a group of the formula — C(=Re)— wherein Reis a divalent C1-12 hydrocarbon group. Certain illustrative examples of dihydroxy compounds that can be used are described, for example, in WO 2013 / 175448 Al, US 2014 / 0295353, and WO 2014 / 072923.

[0015] Specific dihydroxy compounds include resorcinol, 2,2-bis(4-hydroxyphenyl) propane ("bisphenol A" or "BPA"), 3,3-bis(4-hydroxyphenyl) phthalimidine, 2-phenyl-3,3'- bis(4-hydroxyphenyl) phthalimidine (also known as N-phenyl phenolphthalein bisphenol, "PPPBP", or 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-l-one), l,l-bis(4-hydroxy-3- methylphenyl)cyclohexane, and l,l-bis(4-hydroxy-3-methylphenyl)-3,3,5- trimethylcyclohexane (isophorone bisphenol).

[0016] "Polycarbonate" as used herein also includes copolymers comprising carbonate units and ester units ("poly(ester-carbonate)s", also known as polyesterpolycarbonates). Poly(ester-carbonate)s further contain, in addition to recurring carbonate chain units of formula (1), repeating ester units of formula (4):(4)O O- C — T — C — O — J — O -4SUBSTITUTE SHEET (RULE 26)

[0017] wherein J is a divalent group derived from a dihydroxy compound (which includes a reactive derivative thereof), and can be, for example, a C2-10 alkylene, a C6-20 cycloalkylene a C6-20 arylene, or a polyoxyalkylene group in which the alkylene groups contain 2 to 6 carbon atoms, specifically, 2, 3, or4 carbon atoms; and T is a divalent group derived from a dicarboxylic acid (which includes a reactive derivative thereof), and can be, for example, a C2-20 alkylene, a C6-20 cycloalkylene, or a C6-20 arylene. Copolyesters containing a combination of different T or J groups can be used. The polyester units can be branched or linear.

[0018] Specific dihydroxy compounds include aromatic dihydroxy compounds of formula (2) (e.g., resorcinol), bisphenols of formula (3) (e.g., bisphenol A), a C1-8 aliphatic diol such as ethane diol, n-propane diol, i-propane diol, 1,4-butane diol, 1,6-cyclohexane diol, 1,6-hydroxymethylcyclohexane, or a combination comprising at least one of the foregoing dihydroxy compounds. Aliphatic dicarboxylic acids that can be used include Ce- 20 aliphatic dicarboxylic acids (which includes the terminal carboxyl groups), specifically linear Cs-i2 aliphatic dicarboxylic acid such as decanedioic acid (sebacic acid); and alpha, omega-Cu dicarboxylic acids such as dodecanedioic acid (DDDA). Aromatic dicarboxylic acids that can be used include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, 1,6-cyclohexane dicarboxylic acid, or a combination comprising at least one of the foregoing acids. A combination of isophthalic acid and terephthalic acid wherein the weight ratio of isophthalic acid to terephthalic acid is 91:9 to 2:98 can be used.

[0019] Specific ester units include ethylene terephthalate units, n-propylene terephthalate units, n-butylene terephthalate units, ester units derived from isophthalic acid, terephthalic acid, and resorcinol (ITR ester units), and ester units derived from sebacic acid and bisphenol A. The molar ratio of ester units to carbonate units in the poly(ester-carbonate)s can vary broadly, for example 1:99 to 99:1, specifically, 10:90 to 90:10, more specifically, 25:75 to 75:25, or from 2:98 to 15:85.

[0020] The polycarbonates can have an intrinsic viscosity, as determined in chloroform at 25 °C, of 0.3 to 1.5 deciliters per gram (dl / gm), specifically 0.45 to 1.0 dl / gm.5SUBSTITUTE SHEET (RULE 26)The polycarbonates can have a weight average molecular weight of 5,000 to 200,000 Daltons, specifically 15,000 to 100,000 Daltons, as measured by gel permeation chromatography (GPC), using a crosslinked styrene-divinyl benzene column and calibrated to polycarbonate references. GPC samples are prepared at a concentration of 1 mg per mL (mg / mL) and are eluted at a flow rate of 1.5 mL per minute.

[0021] The polycaprolactone may be any suitable such as those in the art. For example, the PCL may be any that realizes the composition and in particular one that realizes the desired printability (e.g., in the absence of supplemental stage heating) and properties such as impact resistance. The polycaprolactone generally has sufficient molecular weight so that it is a solid at room temperature ~20 °C. Generally the polycaprolactone has a molecular weight of at least about 10,000 or 30,000 Da to any practicable molecular weight such as 500 kDa. The high molecular weight polycaprolactones illustrative may be represented by:

[0022] where R1is hydrogen or an aromatic or a straight chain or branched aliphatic backbone, which can optionally contain one or more non-interfering substituents such as hydroxyl or amine groups, w is 1 if R1is hydrogen, and w otherwise has an average value of about 1 to about 4, M1is oxygen or — NR2— where R2 is hydrogen or a non-interfering aromatic or aliphatic group, and the product of w times x is greater than about 175. The product of w times x is preferably at least about 250 and more preferably between about 250 and about 440. Such PCLs may be produced by known methods such as those described in U.S. Pat. Nos. 2,890,208; 3,021,309; 3,021,317 and 3,919,163. The PCL may be those available under CAS Registry No. 25248-42-4 and those under the Tradenames VIATEL from Ashland and CAPA from Perstorp.

[0023] In an embodiment the composition is comprised of a polycarbonate modified with the polysiloxane (polycarbonate-polysiloxane copolymer) such as described in U.S.6SUBSTITUTE SHEET (RULE 26)Pat. Nos. 2,999,845; 4,732,949; 5,322,882; 5,455,310; 5,530,083; 5,986,019; 6,066,700 and 6,072,011, and PCT Pub. WO 2003025063, each incorporated herein by reference. Examples of these copolymers include those commercially available under the TARFLON VG from Idemitsu, Japan. In another illustration, the polycarbonate is a blend with a polysiloxane, that is desirably a high molecular weight polysiloxane (e.g., at least 500,000 or 1,000,000 daltons) that may be unreactive with the polycarbonate or partially reactive with the polycarbonate as described in Polymer 51 (2010) 1990-1999, incorporated herein by reference in which unreacted or free polysiloxane domains are distributed throughout the melt blend of polycarbonate and desirably have an average size of about 0.1 micrometer to 2 or 1 micrometer. The size may be determined by micrographic techniques well known in the art. The amount of polysiloxane blended with the polycarbonate typically is low and may range from about 0.1%, 0.5% to 20%, 15%, 10% or 5%, by weight. An illustrative example of a polycarbonate modified or melt blended with an ultrahigh molecular weight polysiloxane (e.g., polydimethylsiloxane) are those available under the tradename TRIVEX from Trivalence, Evansville IN.

[0024] The composition may desirably have further components and in particular, the composition may be further comprised of a plasticizer such as those known in the plastic art. Illustratively the plasticizer may be phosphate ester such as one or more of Triphenyl Phosphate, Tricresyl Phosphate (mixture of isomers), Triethyl Phosphate, Triamyl Phosphate, Trimethyl Phosphate, Tris(2-ethylhexyl) Phosphate, Tri-o-cresyl Phosphate, Tris(2-butoxyethyl) Phosphate, Tris(2-chloroethyl) Phosphate, Tris(l,3-d ichloro-2-propyl) Phosphate, 2-Ethylhexyl Diphenyl Phosphate, Cresyl Diphenyl Phosphate (mixture of analogue). The plasticizer may be present in any useful amount and typically is from about 0.1, 0.5 or 1% to about 10%, or 5% by weight of the composition.

[0025] The composition may desirably be comprised of an impact modifier such as those known in the art. Illustratively, the impact modifier may be core shell rubber. The core shell rubber is comprised of particles having a core of elastomeric material and a shell of a protective material. Typically, the core is comprised of an elastomer having a low Tg to realize the toughening of the toughened thermoplastic polymer such as about7SUBSTITUTE SHEET (RULE 26)0 °C or less, about -25 °C or less, or about -40 °C or less. Exemplary core materials include polymers of siloxanes, silicones, ethylene, propylene, butadiene, acrylates, methacrylates and the like.

[0026] The shell is a relatively rigid polymer and may contain reactive groups that react with the polyester. Exemplary reactive groups on the surface of the shell of the core shell rubber may include glycidyl, maleic anhydride, and the like. The shell may further comprise polymer chains derived from one or more monomers that form rigid polymer chains. Any monomers which form rigid polymer chains may be utilized. The monomers may polymer-ize by free radical polymerization. The monomers may be capable of polymerizing in emulsion polymerization processes. Exemplary classes monomers are alkyl (meth) acryl-ates, styrenics, acrylonitriles, and the like. Exemplary alkyl (meth)acrylates include alkyl acrylates, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and alkyl methacrylates, such as hexyl methacrylate, 2-ethylhexyl methacrylate, n-lauryl methacrylate, n-butyl acrylate may be preferred. The shell may be prepared from alkyl (meth)acrylates, crosslinkers and graftactive monomer units. Multifunctional compounds may be used as crosslinkers. Examples include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate and 1,4-butylene glycol dimethacrylate. The following compounds individually or in mixtures may be used for inserting graft-active sites: allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, allyl methacrylate. Allyl methacrylate may also act as cross-linker. These compounds may be used in amounts of about 0.1 to about 20 percent, based on the weight of core shell rubber. The preferred graft shell includes one or more (meth)acrylic acid (Cl-C8)-alkyl esters, especially methyl methacrylate copolymerized with glycidyl(meth)acrylate.

[0027] The core may have grafting sites on its outer surface to facilitate bonding of the shell to the core. The core is a particle having a sufficient size to positively impact the impact properties and the environmental stress crack resistance of the composition of the invention. The particles size may be a median particle size (d50 value) of about 0.05 microns or greater or about 0.1 microns or greater. The particles size may be a median8SUBSTITUTE SHEET (RULE 26)particle size (d 50 value) of about 5.0 microns or less, about 2.0 microns of less or about. 1.0 micron or less. The weight ratio of the core to the shell may be any as typically used in the art such as from about 1:99 or greater, about 2:98 or greater or about 3:97 or greater. The weight ratio of the core to the shell may be about 95:5 or less, about 90:10 or less or about 80:20 or less. The impact modifier may be present in any useful amount such as from about 0.5%, 1% or 2% to about 10%, 7% or 5% of the composition by weight.

[0028] The composition may be comprised of further additives and can be particulate materials and include organic and inorganic materials such as fillers, flow agents, and coloring agents. Still other additional components may include, for example, toners, extenders, fillers, colorants (e.g., pigments and dyes), lubricants, anticorrosion agents, thixotropic agents, dispersing agents, antioxidants, adhesion promoters, light stabilizers, organic solvents, surfactants, flame retardants, anti-static agents, and any combination thereof. In certain embodiments, each optional component, if present at all, can be present in the composition in an amount of 0.01 wt % to 30 wt %, based on the total weight of the composition. The total amount of all optional components in the powder composition can range from greater than 0 up to 30 wt % based on the total weight of the composition.

[0029] The composition is desirably a filament useful in the FFF additive manufacturing method and typically is a filament having a diameter of about 0.5 mm to about 3 mm. To make the composition it has been discovered that the polycarbonate is first melted with any other components other than the PCL and any plasticizer. In a particular illustration, the method comprises, melt blending a polycarbonate, polysiloxane and polycaprolactone comprising, heating for a total time above the polycarbonate's melt temperature, the polycarbonate, and polysiloxane for an initial time to form an initial polymer melt, adding, after the initial time, the polycaprolactone and a plasticizer at an interim time later than the initial time to form a melt blend and cooling to form a melt blended composition. The method desirably is performed under a sufficient amount of shear to incorporate any particulate additives and sufficiently blend the PCT without degrading it to realize the desired mechanical properties useful in a9SUBSTITUTE SHEET (RULE 26)safety device. The polysiloxane may be present as a separate polymer within the blend, may be reacted with the polycarbonate to form a copolymer or combination thereof, or combination thereof.

[0030] An exemplary method comprises melt extruding through an extruder (e.g., twin rotating extruder) having a barrel with a feed on one end and a die on the other end of the length of the barrel. Desirably, the polycarbonate is fed at the feed at one end and the polycaprolactone is fed further along the barrel at a lower temperature used to melt the polycarbonate. Illustratively, the PCL may be introduced from 1 / 3 of the barrel's length from the feed to the within 1 / 8 the barrel's length to the die. Other components such as the plasticizer may also be introduced a distance from the feed.

[0031] The melt blended composition is particularly suited to form a filament useful for FFF additive manufacturing of safety devices such as those known in the art including, for example, shin guard, vest, elbow guard, shoulder pad, or helmet (e.g., bike helmet).

[0032] In an embodiment, a heated single or twin screw extruder may be employed such as those known in the art. The amount of shear may be any useful to realize the melt blended composition. The extruder may be held at one temperature or have a gradient along the length of the extruder to facilitate blending, but as described it is desirable for the initial temperature to be higher than where the PCL is introduced. For example, it may be desirable for the initial temperature to be 5%, 10% or 20% higher than where the PCL is introduced. Typical temperature for forming the composition range from about 200 °C to 300 °C. Illustratively the initial temperature or temperature prior to the introduction of the PCL maybe from about 300 °C or 290 °C to 250 °C and the interim temperature be from about 200 °C, 220 °C or 230 °C to about 250 °C. In an embodiment the feed segment may be at a lower temperature and subsequently raised prior to lowering when introducing the PCL.ILLUSTRATIVE EMBODIMENTS

[0033] Embodiment 1. A composition comprising a melt blend of: (i) a polycarbonate, and (ii) a polycaprolactone.10SUBSTITUTE SHEET (RULE 26)

[0034] Embodiment 2. The composition of Embodiment 1 further comprising an impact modifier.

[0035] Embodiment 3. The composition of either Embodiment 1 or 2, wherein the polycarbonate is comprised of one or more of a polycarbonate-polysiloxane copolymer or blend of polycarbonate and polysiloxane.

[0036] Embodiment 4. The composition of either Embodiment 1 or 2, wherein the composition is further comprised of a plasticizer.

[0037] Embodiment 5. The composition of any one of the preceding Embodiments, wherein the polycarbonate / polycaprolactone has a weight ratio of 1 to 25.

[0038] Embodiment 6. The composition of Embodiment 5, wherein the amount of polycarbonate is present in an amount of 90% to 60% by weight, the polycaprolactone is present in an amount of 10% to 30% by weight, and the impact modifier is present in an amount of 0.5% to 10% by weight of the composition.

[0039] Embodiment ?. The composition of any one of Embodiments, 2 to 6 wherein the impact modifier is a core shell rubber.

[0040] Embodiment 8. The composition of any one of the preceding Embodiments further comprising one or more of a UV stabilizer, filler, lubricant, plasticizer, pigment, flow aid, gloss modifier, and flame retardant.

[0041] Embodiment 9. The composition of Embodiment 8, wherein the composition is comprised of at least one of the UV stabilizer, gloss modifier, and flame retardant.

[0042] Embodiment 10. The composition of Embodiment 9, wherein the composition is comprised of the UV stabilizer.

[0043] Embodiment 11. The composition of any one of the preceding Embodiments, wherein the composition is a filament.

[0044] Embodiment 12. A method of forming an additive manufactured article, comprising heating and extruding the filament of Embodiment 11 and depositing the extruded filament in multilayers by a fused filament fabrication (FFF) additive manufacturing method.11SUBSTITUTE SHEET (RULE 26)

[0045] Embodiment 13. The method of Embodiment 12, wherein the FFF is performed in air without supplemental heating of the additive manufactured article during fabrication.

[0046] Embodiment 14. The method of any one of the preceding Embodiments, wherein the additive manufactured article is a protective device.

[0047] Embodiment 15. The method of Embodiment 14, wherein the protective device is a shin guard, elbow guard, shoulder pad, or helmet.

[0048] Embodiment 16. An article comprised of a composition comprising, a melt blend of a polycarbonate, a polycaprolactone, and a polysiloxane.

[0049] Embodiment 17. The article of Embodiment 16 further comprising an impact modifier.

[0050] Embodiment 18. The article of either Embodiment 16 or 17, wherein the polycarbonate and polysiloxane are at a polycarbonate / polysiloxane weight ratio of 20 to 100.

[0051] Embodiment 19. The article of Embodiment 17, wherein the amount of polycarbonate present in an amount of 90% to 60% by weight, the polycaprolactone is present in an amount of 10% to 30% by weight, the impact modifier is present in an amount of 0.5% to 10% by weight of the composition.

[0052] Embodiment 20. The article of any one of Embodiment 17 to 19, wherein the impact modifier is a core shell rubber.

[0053] Embodiment 21. The article of any one of Embodiments 16 to 20, wherein the article is a fused filament fabrication additive manufactured article.

[0054] Embodiment 22. The article of any one of Embodiment 16 to 21, wherein at least a portion of the polysiloxane is present as a polycarbonate-polysiloxane copolymer.

[0055] Embodiment 23. The article of Embodiment 22, wherein the polysiloxane is present solely as a polycarbonate-polysiloxane copolymer.12SUBSTITUTE SHEET (RULE 26)

[0056] Embodiment 24. The article of any one of Embodiment 16 to 22, wherein the polysiloxane is present as a polycarbonate-polysiloxane copolymer and free polysiloxane domains.

[0057] Embodiment 25. The article of any one of Embodiment 16 to 23, wherein the polysiloxane is present in an amount of 0.1% to 10% by weight of the polycarbonate and polysiloxane.

[0058] Embodiment 26. A method of melt blending a polycarbonate, polysiloxane and polycaprolactone comprising, heating for a total time above the polycarbonate's melt temperature, the polycarbonate, and polysiloxane for an initial time to form an initial polymer melt, adding, after the initial time, the polycaprolactone and a plasticizer at an interim time later than the initial time to form a melt blend and cooling to form a melt blended composition.

[0059] Embodiment 27. The method of Embodiment 26, further comprising adding an impact modifier.

[0060] Embodiment 28. The method of Embodiment 26 or 27, wherein the method comprising melt extruding through an extruder having a barrel, feed at one end of the barrel's length and a die at the other end.

[0061] Embodiment 29. The method of Embodiment 28, wherein the polycaprolactone and plasticizer are fed into the barrel's length 1 / 3 of the barrel's length from the feed to the within 1 / 8 the barrel's length to the die.

[0062] Embodiment 30. The method of Embodiment 28 or 29, wherein the heating is at an initial temperature at the initial time that is greater than a subsequent temperature at the interim time.

[0063] Embodiment 31. The method of any one of Embodiments 26 to 30, wherein the plasticizer is a phosphate ester.

[0064] Embodiment 32. The method of any one of Embodiments 26 to 31, wherein the melt blended composition is a filament.13SUBSTITUTE SHEET (RULE 26)

[0065] Embodiment 33. A safety device comprised of a fused filament fabrication manufactured article comprising a melt blend of a polycarbonate and polycaprolactone.

[0066] Embodiment 34. The safety device of Embodiment 33, wherein the melt blend is further comprised of an impact modifier.

[0067] Embodiment 35. The safety device of either Embodiment 33 or 34 further comprising a plasticizer.

[0068] Embodiment 36. The safety device of Embodiment 35, wherein the impact modifier is a core shell rubber and the plasticizer is a phosphate ester.

[0069] Embodiment 37. The safety device of any one of Embodiments 33 to 37, wherein the melt blend is further comprised of a polysiloxane.

[0070] Embodiment 38. The safety device of Embodiment 37, wherein the polysiloxane comprises one or more of a polycarbonate-polysiloxane copolymer and polysiloxane domains within the melt blend.

[0071] Embodiment 39. The safety device of Embodiment 38, where the polysiloxane is comprised of both the polycarbonate-polysiloxane copolymer and polysiloxane domains and the domains have an average size of 0.1 to 1 micrometer.EXAMPLES

[0072] The following examples are provided to illustrate the method and the polymers formed by them but are not intended to limit the scope thereof. All parts and percentages are by weight unless otherwise noted.Each of the examples and comparative examples were performed in a 27 mm twin screw extruder / compounder at 400 revolutions per minute loaded at 60 pounds per hour with the extruder having a length / diameter ratio of 40 and the temperature is between 280 °C and 240 °C along the length of the extruder from input to exit through the die (i.e., somewhat linear gradient from beginning to end). The extrusion is performed under14SUBSTITUTE SHEET (RULE 26)atmospheric pressure. The temperature profile of the segments from the feed to the die are 220 - 280 - 280 - 280 - 270 - 260 - 250 - 240 - 240 - 240 in Celsius. The polycaprolactone and plasticizer are fed about1Z way down the barrel of the extruder and all other components are fed at the feed end. The composition is fed through a die having a diameter of about 2 mm, which is then 3D printed on a commercial 3D FFF printer at the same conditions in air and without supplemental heating. The differing components used are in Table 1. The compositions of the samples are shown in Table 2. The results are shown in Table 3. Table 4 shows a comparison to a commercial polyamide 3D and composition of the example formulation 17 (PC material) 3D printed. The commercial polyamide contains ~10% by weight of chopped carbon fiber to realize the desired properties for safety devices such as a bike helmet, whereas the composition of the present invention realizes the desired properties without the need for any chopped fibers.15SUBSTITUTE SHEET (RULE 26)Table 1.16SUBSTITUTE SHEET (RULE 26)Table 2.Table 3.Table 4

Claims

CLAIMSWhat is claimed is:Claim 1. A composition comprising a melt blend of:(i) a polycarbonate, and(ii) a polycaprolactone.Claim 2. The composition of claim 1 further comprising an impact modifier.Claim 3. The composition of claim 1, wherein the polycarbonate is comprised of one or more of a polycarbonate-polysiloxane copolymer or blend of polycarbonate and polysiloxane.Claim 4. The composition of claim 1, wherein the composition is further comprised of a plasticizer.Claim 5. The composition of claim 1, wherein the polycarbonate / polycaprolactone has a weight ratio of 1 to 25.Claim 6. The composition of claim 5, wherein the amount of polycarbonate is present in an amount of 90% to 60% by weight, the polycaprolactone is present in an amount of 10% to 30% by weight, the impact modifier is present in an amount of 0.5% to 10% by weight of the composition.Claim 7. The composition of claim 2 wherein the impact modifier is a core shell rubber.Claim 8. The composition of claim 1 further comprising one or more of a UV stabilizer, filler, lubricant, plasticizer, pigment, flow aid, gloss modifier, and flame retardant.Claim 9. The composition of claim 8, wherein the composition is comprised of at least one of the UV stabilizer, gloss modifier, and flame retardant.Claim 10. The composition of claim 9, wherein the composition is comprised of the UV stabilizer.Claim 11. The composition of claim 1, wherein the composition is a filament.Claim 12. A method of forming an additive manufactured article, comprising heating and extruding the filament of claim 11 and depositing the extruded filament in multilayers by a fused filament fabrication (FFF) additive manufacturing method.Claim 13. The method of claim 12, wherein the FFF is performed in air without supplemental heating of the additive manufactured article during fabrication.Claim 14. The method of claim 12, wherein the additive manufactured article is a protective device.Claim 15. The method of claim 14, wherein the protective device is a shin guard, elbow guard, shoulder pad, or helmet.Claim 16. A 3d manufactured article comprised of a composition comprising, a melt blend of a polycarbonate, a polycaprolactone, and a polysiloxane.Claim 17. The 3d manufactured article of claim 16 further comprising an impact modifier.Claim 18. The 3d manufactured article of claim 16, wherein the polycarbonate and polysiloxane are at a polycarbonate / polysiloxane weight ratio of 20 to 100.Claim 19. The 3d manufactured article of claim 17, wherein the amount of polycarbonate present is an amount of 90% to 60% by weight, the polycaprolactone is present in an amount of 10% to 30% by weight, and the impact modifier is present in an amount of 0.5% to 10% by weight of the composition.Claim 20. The 3d manufactured article of claim 17, wherein the impact modifier is a core shell rubber.Claim 21. The 3d manufactured article of claim 20, wherein the article is a fused filament fabrication additive manufactured article.Claim 22. The 3d manufactured article of claim 16, wherein at least a portion of the polysiloxane is present as a polycarbonate-polysiloxane copolymer.Claim 23. The 3d manufactured article of claim 22, wherein the polysiloxane is present solely as a polycarbonate-polysiloxane copolymer.Claim 24. The 3d manufactured article of claim 16, wherein the polysiloxane is present as a polycarbonate-polysiloxane copolymer and free polysiloxane domains.Claim 25. The 3d manufactured article of claim 16, wherein the polysiloxane is present in an amount of 0.1% to 10% by weight of the polycarbonate and polysiloxane.Claim 26. A method of melt blending a polycarbonate, polysiloxane and polycaprolactone comprising, heating for a total time above the polycarbonate's melt temperature, the polycarbonate, and polysiloxane for an initial time to form an initial polymer melt, adding, after the initial time, the polycaprolactone and a plasticizer at an interim time later than the initial time to form a melt blend and cooling to form a melt blended composition.Claim 27. The method of claim 26, further comprising adding an impact modifier.Claim 28. The method of claim 26, wherein the method comprising melt extruding through an extruder having a barrel, feed at one end of the barrel's length and a die at the other end.Claim 29. The method of claim 28, wherein the polycaprolactone and plasticizer are fed into the barrel's length 1 / 3 of the barrel's length from the feed to the within 1 / 8 the barrel's length to the die.Claim 30. The method of claim 29, wherein the heating is at an initial temperature at the initial time that is greater than a subsequent temperature at the interim time.Claim 31. The method of claim 26, wherein the plasticizer is a phosphate ester.Claim 32. The method of claim 26, wherein the melt blended composition is a filament.Claim 33. A safety device comprised of a fused filament fabrication manufactured article comprising a melt blend of a polycarbonate and polycaprolactone.Claim 34. The safety device of claim 33, wherein the melt blend is further comprised of an impact modifier.Claim 35. The safety device of claim 34 further comprising a plasticizer.Claim 36. The safety device of claim 35, wherein the impact modifier is a core shell rubber and the plasticizer is a phosphate ester.Claim 37. The safety device of claim 33, wherein the melt blend is further comprised of a polysiloxane.Claim 38. The safety device of claim 37, wherein the polysiloxane comprises one or more of a polycarbonate-polysiloxane copolymer and polysiloxane domains within the melt blend.Claim 39. The safety device of claim 38, where the polysiloxane is comprised of both the polycarbonate-polysiloxane copolymer and polysiloxane domains and the domains have an average size of 0.1 to 1 micrometer.

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